SPAST Abstracts https://spast.org/techrep <p><strong>SPAST Abstracts </strong>publishes the extended abstracts of the papers presented in the First International Conference on Technologies for Smart Green Connected Society 2021</p> <p><strong>SPAST Abstracts </strong>are open access and provide the audience with the insights into the latest research trends in the field.</p> <p><strong>SPAST Abstracts </strong>is the part of the SPAST Open Access Research series and is google scholar indexed.</p> <p> </p> en-US office@spast.org (Office-SPAST) info@spast.org (Support) Sun, 18 Jul 2021 00:00:00 +0000 OJS 3.2.1.0 http://blogs.law.harvard.edu/tech/rss 60 Investigation on Thermal Stress Analysis of Brake Disc Using ANSYS simulation https://spast.org/techrep/article/view/2393 <p>The brake system is a basic and one of the most important systems of an automobile vehicle. Brake rotors of disc brakes rotate with the wheels, and brake pads, which are fitted to the brake calipers, clamp on these rotors to stop or decelerate the wheels. They convert the vehicles kinetic energy into heat, vibration &amp; sound energies, so that the vehicle can be brought to a halt. This change in energy occurs between the brake pads &amp; the rotors or disc in a disc brake system. In this study we focus on the high thermal stresses endured by the disc during this energy conversion. Due to these stresses, the material used for the discs becomes a very important factor as we have to choose the right material which can make these discs efficient and more durable. In this research work, the Formula Student Vehicle disc has been chosen and simulation of the thermal stresses and fatigue analysis with different materials of stainless steels (SS) grades like SS 304, SS 410, SS 321, and SS 310 has carried. These materials were chosen as these are readily available and the cost of manufacturing of these discs will reduce. By the use of Solidworks software, the disc is designed and then with the help of Ansys workbench, the simulation of the thermal stress analysis &amp; fatigue of the discs has been done. The brake disc designed is topologically optimized to reduce the weight in areas of more stress concentration due to the forces from the calipers. From this research output, the stainless steels grade SS 410 has better results than the SS 304, SS 410, SS 321 and SS 310 in various thermal properties and hence it is great replacement in the disc brakes in near future.</p> Pranav Joshi Copyright (c) 2021 Pranav Joshi https://spast.org/techrep/article/view/2393 Wed, 13 Oct 2021 00:00:00 +0000 Design and optimization of FGVM acoustic linings for deep-water applications https://spast.org/techrep/article/view/2952 <p>Underwater acoustic linings are designed to obtain the acoustic performance as per the requirement. While for a submarine, stealth is of utmost importance, for others like seabed mapping, remote sensing, etc., accuracy in positioning, improving the communication capability, etc. might be necessary. These linings are vital for maritime applications in reducing the underwater radiated noise. The acoustic performance of a lining can be quantified by two parameters: Echo reduction (ER) to measure the efficiency of the linings in avoiding the reflections, and Transmission Loss (TL) to effectively circumvent the transmission of acoustic waves. The design of such a lining necessarily encapsulates scatterers distributed inside a viscoelastic material. The first design and analysis of such a lining can be dated back to 1957 when Obesrt [1]and Meyer [2] developed a lumped model to represent a cylindrical cell. Later, Gaunard [3] and Lane [4] developed a one-dimensional analytical model for investigation of viscoelastic materials containing cylindrical cavities, and presented the various modes of resonances for the geometrical properties of the cavity. Stifors and Gaunard [5] analysed a bilaminar structure and highlighted the importance of a rigid structure behind the coating. Meng [6] presented a simplified two-dimensional analytical model to predict the acoustic performance of such underwater linings and found that for lower frequencies, the first axisymmetric wavenumber corresponding to the first propagation mode should be considered owing to its lower attenuation.<br>However, the suitability of functionally graded viscoelastic materials (FGVM) to such applications has not been fully exploited. The present paper focuses on development of an optimized acoustic lining made up of FGVMs (fig.1) for various applications. A transfer matrix based analytical model has been formulated and has been validated numerically, followed by optimization of the material properties using genetic algorithm and a novel optimization tool based on weight functions. Results show that such materials are effective in obtaining the desired acoustic characteristics. Further they are found to be retaining their performance under hydrostatic pressures. The effect of thickness of various layers and configurations have been discussed. The case of oblique incidence has been considered through the numerically developed model.</p> SHOBHIT MISHRA, Dr. Copyright (c) 2021 SHOBHIT MISHRA, Dr. https://spast.org/techrep/article/view/2952 Fri, 05 Nov 2021 00:00:00 +0000 Experimental Stress Analysis and Stress concentration Factor – A Review https://spast.org/techrep/article/view/840 <p>Machine components goes through various stress conditions and it is essential for a designer to analyze the stresses generated in the component accurately. Experimental stress analysis plays a vital role in designing a component.</p> Ramit Chugh, Dr. Shubhrata Nagpal Copyright (c) 2021 Ramit Chugh, Dr. Shubhrata Nagpal https://spast.org/techrep/article/view/840 Sat, 18 Sep 2021 00:00:00 +0000 Towards Applicability of Machine Learning In Quality Control – A Review https://spast.org/techrep/article/view/2357 <p>With the Growing advent of technology, there is a need to adapt to Machine Learning. This technology will help us in reducing human effort and increasing the Quality of Products.Quality Control is one of the tasks involved in the industry that needs reform in technological field. As an ever-growing technology Machine Learning can provide a suitable solution for fast, accurate and reliable information for quality determination to improve the efficiency of the machining operations. With Machine Learning we have a lot to gain and none to lose. With the coming of new providers of the Internet of Things and Machine Learning technologies, there has been a move from classical approaches of Data acquisition to machine learning-based Data Acquisition methods. In the context of this, there has been a need to critically evaluate classical approaches of Quality Determination for their relevance and substituting them with the new ones. This Review Paper will check into the effectiveness of the Machine Learningbased Quality Determination and its implementation in the industries.</p> Hrishikesh Deshmukh Copyright (c) 2021 Hrishikesh Deshmukh https://spast.org/techrep/article/view/2357 Fri, 08 Oct 2021 00:00:00 +0000 Entropy analysis on pulsatile flow of couple stress nanofluid in a vertical channel: Buongiorno nanofluid model https://spast.org/techrep/article/view/2518 <p>The present work discloses the pulsating flow of couple stress nanofluid in a vertical channel in the presence of applied magnetic field. The Buongiorno nanofluid model is employed in the current study with the analysis of entropy generation. The impressions of viscous dissipation, Joule heating, thermophoresis, thermal radiation, heat source/sink, and Brownian motion are taken into the account. The governing partial differential equations are transformed into the system of ordinary differential equations by employing the perturbation method and then solved by utilizing the Runge-Kutta fourth order scheme with the support of shooting technique. The current concept is noteworthy in the field of energy conservation, dynamics of physiological fluids, and biomedicines. The influences of emerging parameters concerned with the current model on flow variables like velocity, temperature, and concentration are discussed in detail and interpreted graphically.</p> <p>Nanofluids have interesting uses in science and engineering, including as drug delivery, solar absorption, crystal formation, carcinogenic treatment, food biophysics, and biomedicine. Choi and Eastman [1] reported that, the suspension of nanoparticles in a base fluid, improved the heat transfer rate of working fluid. The idea of Brownian motion and thermophoresis effects came into being after Buongiorno [2] came up with a generalized non-homogenous paradigm for transport in nanofluids. Heat and mass transfer caused by non-Newtonian fluid flow are seen as ways to improve research and manufacturing. Non-Newtonian fluid models that are especially useful in industries and engineering include the couple stress fluid model which is useful for synthesized fluids, polymeric materials, biological fluids, solvents, and fluid crystals. As a pioneer in magnetohydrodynamic channel flows, Stokes [3] proposed the concept of coupled stress fluids. In the light of various applications in science and engineering, like dynamics of biological fluids, artificial kidney, pulse jet engines, and identification of water reserves there is a lot to discuss about pulsatile flow. Kumar et al. [4] endeavoured to study the pulsatile flow of a non-Newtonian fluid on the penetrable channel under the influences of Ohmic heating, radiative heat, and applied magnetic field by using the Buongiorno model.</p> RAJAMANI S, Subramanyam Reddy Anala, Srinivas S, Jagadeshkumar K Copyright (c) 2021 RAJAMANI S, Subramanyam Reddy Anala, Srinivas S, Jagadeshkumar K https://spast.org/techrep/article/view/2518 Sun, 17 Oct 2021 00:00:00 +0000 A survey on the Effect of Ventilation on Air Quality in Vehicle Cabin https://spast.org/techrep/article/view/1919 <div> <p>Vehicles have been an essential part of society to go from one place to another place easily. A key component of owning a vehicle is having a system that is able to provide its occupants with a safe and comfortable condition in the cabin. The existence of current heating, ventilation, and air conditioning (HVAC) vehicle systems provide occupants with a comfortable temperature, humidity level, roadway noise and reduce particulate pollutants in the cabin from the pollution. There are two types of ventilation mode in vehicle, recirculation (RC) mode and outside air (OSA) mode. RC mode is a great way to reduce particle pollution while also improving air conditioner cooling performance. However, the prolonged use of recirculation air within a vehicle might create high carbon dioxide (CO<sub>2</sub>) levels due to human exhalation and the lack of fresh air. If using OSA mode, it exposes occupants to roadway contaminants since outside air enters into the vehicle cabin. The driver’s decision impacts the rate of air pollution inside the cabin of the car. In this matter, the car is not a vacuum system so it does not fully protect the outside air from entering inside the cabin even switching RC mode. This is because, the outside air still can enter the cabin through uncontrolled leakages like windows, door seams or hinges. When a car becomes older, the gaps in the body seem to enlarge, resulting in an uptick in uncontrolled leaks. A major source of exposure to multiple air contaminants has been established in-cabin microenvironments, such as particulate matter (PM), the total volatile organic compound (TVOC) and carbon dioxide (CO<sub>2</sub>) concentration [1][2][3]. In this case, human awareness of car cabin air quality is still very poor. The objective of this work is to acknowledge the present pattern of behaviour among driver in Malaysia in utilizing the HVAC system in the car. A questionnaire was used in this study to gather information about the cars, their usage, and the driver's understanding of outside and in-cabin air quality, which was then collected to display the percentage distribution of various responses. It may be an efficient way to measure the behaviour, attitudes, preferences, opinions and intentions of many respondents. This survey has been narrowed down to driver who own a car only in order to get accurate and precise data. A similar sequence of questions is asked to all responders. This makes it easy to reproduce a questionnaire to assess for reliability. The survey was conducted from 26 February 2021 to 24 May 2021. From the survey results, the majority of respondents were not aware that CO<sub>2</sub> levels can be high under prolonged RC mode. In addition, most of the respondents do not know that switching on the RC mode for too long is dangerous for their health. Most of the respondents were spending around 1 hour to 2 hours in a car on average days and they preferred to use RC mode. This demonstrates that most of the respondents like to spend long periods in the car while switching on RC mode. This survey revealed that society may not have a greater understanding of the importance of healthy vehicle indoor air quality.</p> </div> Muhammad Khairul Adha Mohamad Zali, Shaharin Anwar Sulaiman, Badrul Rezza Hakim Burham Copyright (c) 2021 Muhammad Khairul Adha Mohamad Zali, Shaharin Anwar Sulaiman, Badrul Rezza Hakim Burham https://spast.org/techrep/article/view/1919 Sat, 09 Oct 2021 00:00:00 +0000 Aerodynamic Analysis and Optimization of Wings for the Jain University Sailplane using XFLR5 https://spast.org/techrep/article/view/532 <p>There is ever growing interest in the design of high-performance sailplanes since the start of the last century [1-3]. Sailplanes or gliders form an example of sustainable engineering in aeronautics. Sailplanes are testbeds for aerodynamics research in the educational community as there is little to no practically carbon footprint. The design of a sailplane’s wing is of much concern to aerodynamicists as it has to generate sustained lift at a fixed altitude. The students of aerospace engineering at IIAEM, Jain University are tasked with the problem of designing a wing for “Jain Sailplane”, a sailplane that can achieve steady, level flight at 7000 feet altitude (Reynolds number (Re) of 1.46 million). Two teams namely, Airfoil Design sub-group and Aerodynamics and Geometry group [4] comprising thirteen members were tasked with the design of wing. The use of XFLR5, a code based on Vortex Lattice Method, Panel method and Lifting Line Theory is adopted. In the first step, five different low Re airfoils namely CH10, Eppler 420, Wortman FX61-140, S1223 and SM701 are chosen for detailed aerodynamic investigations. The analysis of airfoils showed that the lift variation with angle of attack (<em>ɑ</em>) for SM701 is more linear compared to that of other airfoils as seen in Fig.1. Compared to FX61-140, progression to stall is delayed further and relatively more lift is available at higher <em>ɑ</em> for SM701. Lift curves from other airfoils showed non-linearity which may cause stability issues. The drag for SM701 is lowest among all airfoils, which is particularly noticeable at higher <em>ɑ </em>(Fig.2).&nbsp; The only adverse issue noticed is of negative lift at lower <em>ɑ</em> of ≤5°. The <em>C<sub>l</sub>/C<sub>d</sub></em> curve showed that only some lift is available at <em>ɑ</em> of -5°. Lower than that limit, the glider will experience negative lift. The parasite or profile drag trend of SM701 showed considerable favourability towards selection of this airfoil. The moment for this airfoil is the lowest among the airfoils analysed. A thorough investigation on negative lift of this airfoil was found to be necessary. Hence, in the second step, a 3D wing body with SM701 airfoil cross-sections is analysed for lift and drag characteristics. Preliminary weight estimate of the sailplane [4] was found to be 500 kg. A rectangular planform is selected due to the following reasons: (a) Stall of wing for rectangular planform starts at the root than at the tip (where ailerons are present), (b) lower cost of manufacturability [5]. Six wings namely, Wing-1, Wing-2, Wing-11, Wing-12, Wing-13 and Wing-14 of chord lengths 1m, 0.5m, 1.05 m, 1.1m, 1.15m and 1.2 m respectively with constant span of 20m are analysed. Based on the results of the analysis, Wing-1 is selected on the basis that lift is generated at reasonable ɑ of 3.2⁰ maintained along the span. Wing-2 is disregarded as it requires an <em>α</em> of 14.3⁰. For Wing-11, Wing-12, Wing-13 and Wing-14, the local <em>ɑ</em> requirements are 2.7⁰, 2.4⁰, 2.1⁰ and 1.8⁰ respectively. These values are slightly lower than that of Wing-1, yet, the selection of Wing-1 will be beneficial from structural point of view. It was further proposed Wing-1 design can be further optimized for various local angles of attack throughout the span by incorporating twist. Two twisted wings, Wing-18 (Tw-1) and Wing-19 (Tw-2), based on the Culver twist formula are analyzed and compared with Wing-1. Wing-18’s root <em>α</em> is maintained at 4.11⁰ whereas Wing-19’s root <em>α</em> is 8.22⁰. The results showed that twist induces earlier stall of the wing as seen in Fig.2. Wing-18’s stall angle is reduced to 16.3⁰ from 18.3⁰. The incorporation of twist reduces the design lift coefficient <em>ɑ</em> to be maintained. Both wings’ tip α is 0⁰. Wing-18’s design lift coefficient <em>α</em> of 1.6⁰ requires maintaining a wing with an angle of incidence of 1.6⁰ above the root <em>α</em> which is not an ideal design. Wing-19 on the other hand requires maintaining a lower of incidence of nearly 0⁰ which is ideal. The lift produced by Wing-19 is higher than Wing-1 and Wing-18. Although the induced drag, viscous drag and total drag of Wing-19 is higher among the three wings, at most positive angles of attack, the lift increase is significantly higher for Wing-19. Earlier stall allows reduction in maximum angle of attack attainable, however this factor does not preclude the fact that the wing’s lift capability is higher. The untwisted Wing-1 has the best aerodynamic efficiency (<em>C<sub>L</sub>/C<sub>D</sub></em>) among the three wings for most positive <em>α</em>. Negative <em>α</em> is usually encountered during glide. Hence the efficiency during this flight phase is also important. During this phase, the efficiency of Wing-19 is the highest whereas it is lowest for Wing-1. Wing-1, a rectangular wing has uniform chord along the span is finally selected in a high wing configuration. From this research, it is found that a wing with rectangular planform, chord of 1m and span of 20m is the best design. The results of this investigation will be presented in this paper.</p> Dr. Aravind Seeni Copyright (c) 2021 Dr. Aravind Seeni https://spast.org/techrep/article/view/532 Thu, 16 Sep 2021 00:00:00 +0000 Investigation on Thermal Analysis of Battery in an Electric Car using ANSYS Simulation https://spast.org/techrep/article/view/2445 <p>Electric vehicle performance is depending on the temperature management of the battery packs, which determines the life expectancy and efficiency of the battery system. Optimum temperature is between 20℃ and 30℃ to achieve the better functioning of the system. However, in physical climatic conditions it’s not possible to maintain these optimal temperatures (i.e. extreme temperature conditions like -3℃ to 40℃). So to optimize this problem of temperature gradient, the different boundary conditions such as heat/cold conditions, the coolant Ethelene glycol have to apply. With the aid of chiller (which is used to control the temperature when it’s higher more than 30℃) and heater (which is used to raise the temperature when there is lowering in temperature that is less than 20℃) i.e. for heating or cooling, the driving fluids plays a major role for maintaining optimized temperature. In the present research work, the CAD model of the battery pack is made with a capacity 200KW by using the solid works software. Like most common battery in usage we are going to do analysis with lithium-ion battery With the help of Ansys R19.3. workbench the Finite Element Analysis is carried out by considering both heat/cold boundary conditions to optimize for better functioning of the battery in extreme temperature conditions. From this research output, the Ethelene glycol coolant shows better results in extreme temperature conditions in various thermal properties and hence the results will support better for the battery manufacturer in near future.</p> Gokul S, G Siddartha Naidu, V. Sreenivas Reddy, S. Senthur Prabu Copyright (c) 2021 Gokul S, G Siddartha Naidu, V. Sreenivas Reddy, S. Senthur Prabu https://spast.org/techrep/article/view/2445 Fri, 15 Oct 2021 00:00:00 +0000 Prediction of Performance, Emissions and combustion with Artificial Neural Networks in a single cylinder SI engine using Catalytic Coating https://spast.org/techrep/article/view/1415 <p>In the present study, the effect of copper, nickel and chromium coating on the spark ignition engine performance, emission and combustion characteristics were estimated using the Artificial Neural Network. It was observed that the maximum brake thermal efficiency for copper coated engine is 5% higher than standard engine with full load and about 4% higher than the standard engine at 2800 rpm. The Nitrogen oxides emission for catalytic coated engine is 7% to 20% higher than standard engine with full load. Also from the study we observed that the carbon monoxide and carbon dioxide emissions of standard engine were higher than catalytic coated engines at all loads. Copper coated engine has the lowest hydro carbon emission. Catalytic coated engines have 6% to 12% higher cylinder pressure when compared to the standard engine. The crank angle of heat release values and combustion parameters indicate that a faster heat release occurred for catalyst coated engines. Similarly combustion duration of standard engine is higher than that of catalytic coated engines. Catalytic coatings increase the pre-flame reactions which lead to better and faster combustion. The test data generated from the unused part of the training was measured by comparing the performance using ANN model. According to the data acquired, Artificial Neural Network (ANN) model predicts the exhaust emissions and engine performance with a regression coefficient (R2) at a maximum 8 interval ranges from 0.964–0.987. Also we found that the mean relative error (MRE) values ranged from 0.51% to 4.8%. These results show that the ANN model is able to use for prediction and estimating SI engine characteristics.</p> <p>&nbsp;</p> <p>The fluid oil fills are a constrained and the interest is colossally expanding. The expense of fuel is ever expanding. So as to agree to progressively stringent discharges benchmarks and meet drivability necessities, current vehicle motors are outfitted with an expanding number of subsystems and controlling components. The outcome has been increment in the alignment exertion required to discover the parameter settings that offer the best worldwide intensity. Lessening contamination outflows is an imperative and a constant test for the car business [2]. New advances are being examined, regularly with the point of at the same time improving execution, efficiency, and discharge qualities. Along these lines for acquiring motor fuel utilization and emanation as far as alignment parameters, a motor model is required. On account of exceptionally mind boggling and nonlinear nature of inside burning motors models used to examine are as discovery models.</p> <p>A ground-breaking strategy among discovery displaying methods is the artificial neural system demonstrating which has been generally utilized in different parts of engineering lately. This strategy intends to fundamentally diminish dynamometer test prerequisites by creating scientific models of the motor yields utilizing a littler subset of dynamometer tests [7].&nbsp; When the scientific models have been built up, the adjustment maps can be advanced utilizing systems, for example, slope techniques. Different methodologies have been proposed for utilizing ANN to advance demonstrating and adjustment of motors. The capacity of Artificial Neural Network as a framework ID device is utilized to show non-direct conduct of motor tasks. Numerous analysts utilized ANN for foreseeing torque, power, explicit fuel utilization, and residue development with speed and infusion pressure found the ANN gives exactness and straightforwardness in the investigation of the motor execution. ANN to display for deciding the working parameters of the inward burning motor, for example, pressure in chambers or the air-fuel proportion [4].</p> <p>Be that as it may, in neural system plan determination of system topology, the trigger capacity, learning rule and the criteria or admissible blunder for halting the preparation stage is essential and done by the planner/engineer. Along these lines, it is hard to predefine the size of the system as there is no fixed technique to do it. In spite of this issue, neural systems based arrangement is extremely productive regarding improvement, time and assets. By experience and chipping away at various design, size, and models we can give genuine arrangements. Along these lines, we directed itemized study utilizing various calculations and picked the one that gives the best outcomes to given arrangement of information of motor parameters. ANN demonstrating investigates the exhibition and discharge of vehicle motor. In light of gathered trial information, ANN connects motor working parameters with the presentation parameters and discharge attributes [3].</p> <p>Accordingly, ongoing activity and mapping of complex, non-direct and dynamic examples in motor tasks are difficulties to be met in the present motor advancement. Neural systems designs, mixes of systems, and various calculations assume a significant job on the exhibition [1]. There is a need to utilize ANN as an exhibition basic instrument that spares cost and time in growing new models and approaches for generally motor administration. Further it will help in getting to which calculation is best reasonable for a specific circumstances.</p> <p>The ability of ANN to understand and properly classify a problem of highly non-linear relationship has been established and the significant consideration is that once trained effectively ANN can classify new data much faster than it would be possible with analytical model. A neural network is an enormously equal dispersed processor that has a characteristic affinity for putting away trial information and making it accessible for use [5]. It looks like the cerebrum in two regards [6]: 1. Information is obtained by the system through a learning procedure. 2. Between neuron association qualities known as synaptic loads are utilized to store the information. Our information sources parameters are Fuel Injection Angle (degree BTDC), Fuel Injection Pressure (kgf/cm2), Load (kW), TFUEL (Sec)(For 50 CC), Speed (RPM) and yields are different emanations parameters CO (%Vol), CO2 (%Vol), NOX (ppm), HC, SMOKE (%opacity), and proficiency parameters BTE (%), BSFC (kg/kWh).</p> LOKESHKUMAR R RAMASAMY, PONNUSAMY P, JOTHI K R Copyright (c) 2021 LOKESHKUMAR R RAMASAMY, PONNUSAMY P, JOTHI K R https://spast.org/techrep/article/view/1415 Thu, 07 Oct 2021 00:00:00 +0000 Mathematical Modelling, Design and Optimization of Airfoils and Aircrafts operating at specific Reynolds Number https://spast.org/techrep/article/view/1186 <p>Airfoil design and optimization have become vital aspects of aircraft design in recent years. It still attracts growing interest in the aeronautics community in the search for the most optimum airfoil design of high lift and low drag for a specific operating condition (Reynolds number).&nbsp;</p> <p>Elizarov et al. [1] presented the theory to design an airfoil with C<sub>lmax</sub> ≥ 1.5 with a high aerodynamic ratio (K) ≈ 150, under airfoil thickness constraint of 0.17 ≤&nbsp;t&nbsp;≤ 0.19. The airfoil design process was done by defining the class of velocity distributions and solving them through the inverse method. Separation free high lift airfoil was designed for viscous compressible flow using an iterative method to account for compressibility and viscous distribution. Computational codes coupled with mathematical optimization techniques constitute a powerful tool for developing new airfoil designs for specific requirements. The viscous theory is used for low-speed calculations as well as for sophisticated transonic flow until separation occurs. Navier stokes equations are used in airfoil shape optimization for very low Reynolds number (Re) and laminar flow separation [2]. Potential flow theory and Euler equations are also utilized for airfoil design purposes. In recent times, the viscous inviscid method is also proven remarkable CFD method for airfoil design [3].&nbsp;The parameterization method provides completeness and controllability to produce a broader variety of airfoil shapes. Various parametric methods have been developed like Bezier (Bernstein polynomial) or parametric curve, PARSEC, Hicks-Henne, Nash equilibrium genetic algorithm and Basis-spline curve method [3]. Genetic algorithm is utilized to find more precise, optimum and considerable solutions for aerodynamic optimization design problems. This design technique is specifically concerned with the wing of aircraft. The gradient-based method is mostly preferred for high-speed applications whereas heuristic algorithms are suitable for low-speed applications. In the CFD method, the Re plays an important role. For high Re, where viscous effects are negligible, compressible Euler equations are used. Otherwise, compressible and incompressible RANS equations are used for airfoil design and optimization. Two equation models, eddy viscosity and Spalart–Allmaras single and multi-equation turbulence model are commonly used for these purposes. CFD based on the laminar to turbulent conversion model is used for computing stream variables [3].&nbsp;For airfoil design and optimization, two basic approaches are considered. They are inverse design method based on gradient optimization and direct search algorithm based on numerical optimization. The inverse design method is used when the design is concerned with fluid dynamics parameters such as pressure distribution whereas direct numerical optimization is adopted if geometry having an aerodynamic shape depends on various constraints [2]. In recent years, automated designs methods are used to produce airfoil shapes with definite features but it first requires the consideration of pressure distribution. It necessitates an inner-outer iteration system [3]. Through Joukowsky transformation investigations on airfoils, it is known that the airfoil profile can be expressed through conformal mapping and analytical function of finite series of Fourier expansions. This integrated design method is proven to be more accurate than the traditional inverse design method. XFOIL is based on solving viscous integral boundary layer equation and inviscid Euler equation for airfoil flow predictions [4].&nbsp;</p> <p>In this research, the use of both physical and mathematical modelling along with optimization algorithms to generate new optimum airfoil designs for high lift and low drag for specific operational conditions will be performed. The experimental analysis will also be done by implementing these new airfoils on 3D printed small-scale aircraft models and testing them in the subsonic wind tunnel to correlate with numerical results. This research will focus on addressing several important research questions such as:</p> <ol> <li>How can novel mathematical modelling techniques be used for designing new airfoils?</li> <li>What parameters (camber, thickness etc.) affect the design of an airfoil for various Re conditions?&nbsp;</li> <li>Can currently available numerical codes (i.e. commercial/open source) be used to obtain high-fidelity results in aircraft design at the initial design stages?</li> <li>Can one improve the level of fidelity of results obtained from the conceptual design stage itself through the implementation of advanced design techniques in aircraft design?&nbsp;</li> </ol> <p>This research has the following objectives:</p> <ol> <li>Develop a new design framework in airfoil and aircraft design</li> <li>Testing of new airfoils generated though computational methodology in XFOIL and CFD for different Re</li> <li>Include the new airfoils in opensource conceptual aircraft design code called CEASIOM and test them on wing and other control surfaces in order to find better performance aircraft designs</li> <li>Generate new aircraft designs designed with novel airfoils generated in Step 1.</li> <li>Implement new airfoils on 3D printed small-scale aircraft models and testing in IIAEM's subsonic wind-tunnel to correlate with numerical results.</li> </ol> <p>In this research, the problem of finding the optimum design for high lift and low drag for the specific operational condition will be performed based on initial mathematical modelling and subsequent physics-based analysis. The use of modern technology like CFD and high-fidelity modelling and analysis will be used to achieve the goals.&nbsp;</p> Sayali Kakade, Dr. Aravind Seeni Copyright (c) 2021 Sayali Kakade, Dr. Aravind Seeni https://spast.org/techrep/article/view/1186 Fri, 24 Sep 2021 00:00:00 +0000 A Study on Performance Analysis of Solar Air Heater with Aerofoil Shaped Rib Roughness Using CFD https://spast.org/techrep/article/view/2832 <p>The aim of the present study is to investigate the heat transfer, friction factor and fluid flow characteristics of fully developed turbulent flow in a rectangular duct of solar air heater provided with repeated aerofoil shaped rib-roughness on one broad wall (absorber plate). The commercial CFD software ANSYS FLUENT shall be used to simulate turbulent airflow through an artificially roughened solar air heater. The Reynolds averaged Navier-Stokes equations and the energy equations shall be solved with the Realizable k–ε turbulence model. The roughened wall shall be uniformly heated with constant heat flux, while the remaining three walls shall be kept insulated. Reynolds number, relative roughness height, roughness pitch, aspect ratio and arc length shall be systematically varied. Twelve different configurations of aerofoil shaped rib shall be formulated and investigated based on ranges of parameters. The effects of relative roughness height and roughness pitch of rib on Nusselt number and friction factor shall be investigated and the results shall be compared with that for smooth duct under similar flow conditions. In this research work, the CAD model of the aerofoil shaped fins is made by using the solid works software. A comparative study has been made on the performance evaluation of the conventional fins and aerofoil shaped fins with the help of Ansys workbench and CFD by considering the thermal analysis in solar air heater ducts. From this research output, the aerofoil shaped fins show better results in various thermal properties on different working conditions. Hence it is a great replacement for conventional fins with aerofoil shaped fins in the solar air heater ducts. Therefore the results will support better for the solar air heater ducts manufacturer in near future.</p> Arin Mishra, Aman Mehrotra, S. Senthur Prabhu Copyright (c) 2021 Arin Mishra, Aman Mehrotra, S. Senthur Prabhu https://spast.org/techrep/article/view/2832 Sun, 17 Oct 2021 00:00:00 +0000 Comparative study on thermal properties of 3D printed and conventional fins https://spast.org/techrep/article/view/2602 <p>Fins are a type of heat exchanger that is attached to a part of the product and is mainly used to enhance the heat transfer rates. Fins of different shapes and sizes exist and are used for numerous thermal applications. Fins are generally manufactured using conventional methods such as extrusion, die casting, and forging. But nowadays, there are more efficient ways of manufacturing fins and one of them being Additive Manufacturing (AM). AM is a modern manufacturing technique that is one of the emerging methods to manufacture metallic components such as fins. Some of the advantages of using AM is that it is much more cost-efficient, reduces a lot of material wastage than conventional methods of manufacturing as well as being more time-efficient, which is very important now as we live in a fast-moving world. Another main advantage of AM technique is that it is numerically controlled using computers which can yield much more accurate and better results. The AM process which will be used for the manufacture of fins is either Directed Energy Deposition (DED) or Powder Bed Fusion (PBF). The main reason is that many different alloys can be used like titanium grade 5, Inconel as well as many other highly heat resistant materials. Hence it can even be used in applications that require components to operate at very high temperatures. In this research paper, the effect on heat transfer rates of the fins manufactured using different AM techniques is shown. Furthermore, an analysis of the thermal properties and heat transfer rates of multiple 3D printable materials will be conducted using the Ansys Workbench Mechanical 2018 software. These will then be compared with fins manufactured with conventional manufacturing techniques. The expected research outcomes are that the fins manufacturing using AM techniques will show better thermal properties than the conventional method and hence AM will be a great replacement for conventional manufacturing techniques given the introduction of more 3D printable materials in near future.</p> vaishnav madhavadas, Dibyarup Das, Kaustubh anand mohta, Nevan Nicholas Johnson, S. Senthur Prabu Copyright (c) 2021 vaishnav madhavadas, Dibyarup Das, Kaustubh anand mohta, Nevan Nicholas Johnson, S. Senthur Prabu https://spast.org/techrep/article/view/2602 Sun, 17 Oct 2021 00:00:00 +0000 A review on advanced monitoring and identifying the status of grinding machine using machine learning algorithms https://spast.org/techrep/article/view/493 <p>Recently, the development of the grinding process is improved by including automatic sensors, actuators, control systems, artificial intelligence, and industrial internet of things in the grinding machine. Already existing contact type techniques are replaced with the automatic sensor system to incorporate artificial intelligence in the normal grinding process. Therefore, optical and laser technology is emerging as a smart device to observe the surface topography of the grinding wheel, surface finish of the ground surface, and automatic dressing process. Moreover, artificial intelligence consists of machine learning which teaches the grinding machine based on the existing data available to improve the quality and the production rate of the grinding process. This can be achieved by controlling the process parameter, monitoring the machine's health, and attaining optimum conditions. The present review paper addresses the existing problems associated with the contact type and non-contact type measurement. The study also emphasizes the importance of machine learning algorithms to predict the failure of the grinding wheel and the surface roughness of workpiece material in the grinding process.</p> Suya Prem Anand P, Sivakumar R, Prabadevi B Copyright (c) 2021 Suya Prem Anand P, Sivakumar R, Prabadevi B https://spast.org/techrep/article/view/493 Fri, 17 Sep 2021 00:00:00 +0000 Investigating the Effect of Different Car Coolants on an Automobile Radiator using ANSYS Simulation https://spast.org/techrep/article/view/2645 <p>Every automobile engine generates heat energy when it is runs,&nbsp;the excess heat energy produced but not converted into work is required to be extracted out from the engine for proper working of the engine. So the Radiators are used for this function. Radiator is part of the cooling system of an automobiles which transfers engine heat to the environment through conduction and convection process. In a combustion engine only a small part of total energy generated is used for driving rest is wasted in the form of heat, so it’s vital to remove heat energy from the engine. If heat is not taken out of the engine then it would cause overheating of the engine, due to which breakdown of viscosity of lubricating oil, breakdown of engine parts can take place. Also the amount of heat energy generated varies as the automobile travels at various speeds so power the engine is generating also changes. So the cooling process needs to be sufficient to remove the highest amount of heat energy generated during the whole ride. The main purpose of the radiator is to maintain the optimum temperature of the engine for maximum output from it. The radiator is part of the cooling system for the engine. The radiator's function is to extract heat from fluid flowing through it. The cooling system starts with water pump It contains water mixed with antifreeze, the mixture is called a coolant. Coolant is pumped into the engine through the water pump, it extracts dissipated heat or waste heat from engine parts and when its temperature is increased above threshold temperature it passes through passage around the cylinders in the engine to above part where thermostat valve is present which opens after coolant temperature is increased above a threshold temperature. Now coolant enters into the radiator through the inlet hose or upper hose.</p> <p>In radiator coolant flows through many tubes mounted in parallel arrangement from top to bottom. The fins conduct the heat from tubes and transfer it to the air flowing through a radiator by convection and a fan is also present behind the radiator for efficient suction of air. Pressure cap is present on top of radiator to regulate pressure of the fluid. Tubes can have a type of fin inserted in it called a turbulator, the function of a fin or turbulator is to increase turbulence of fluid flowing through it, thereby all of the fluid mixes and heat from all of the fluid is extracted efficiently. Then fluid goes to the lower hose after cooling down and from there it enters into the water pump and this cycle goes on to maintain the optimum temperature of the engine to protect its part from deformation due to excess dissipated heat.</p> <p>The thermal simulation are carried out using ANSYS Fluent software and the model will be made in Solidworks. By applying boundary conditions based on other papers we are going to validate the results. Further which we will be adding new coolants such as</p> <ol> <li>Ethylene Glycol</li> <li>Diethylene Glycol</li> <li>Triethylene Glycol</li> <li>Propylene Glycol</li> <li>Methyl Ether</li> </ol> <p>From this research output, the Ethelene glycol coolant shows better results compared to other coolants in extreme temperature conditions in various thermal properties and hence the results will support better for the radiator manufacturer in near future.</p> Hem Joiser, Akshay Badagabettu, Sai Sravan Yarlagadda, Fenish Sinojiya, Hardik Shukla, Senthur Prabu S Copyright (c) 2021 Hem Joiser, Akshay Badagabettu, Sai Sravan Yarlagadda, Fenish Sinojiya, Hardik Shukla, Senthur Prabu S https://spast.org/techrep/article/view/2645 Sun, 17 Oct 2021 00:00:00 +0000 COMPUTATIONAL STUDY ON THE EFFECT OF AFD-BODY ATTACHMENT ON BASE DRAG USING LOCKED VORTEX METHOD https://spast.org/techrep/article/view/1168 <p>Мinimization of drag has always been a concern to achieve high efficiency and performance. Drag reduction techniques can be used to minimize vortex shedding and make, this method can be used for building launch vehicles and missiles. Vortex shedding can be observed when there for over blufſ body, which creates drag. Design modification like the attachment of splitter plates to the base of the body helps to trap the vertices and suppress vortex shedding. It also helps in recovering the pressure at the base of the body. This can be considered as the most effective passive control technique. The paper mainly focuses about the computational study on the effect of aft-body attachment on base drag using locked vortex flow management technique which prove to be an efficient method in reducing drag.</p> Judy Rabaa, ASHOK KUPPUSAMY Copyright (c) 2021 Judy Rabaa, ASHOK KUPPUSAMY https://spast.org/techrep/article/view/1168 Fri, 24 Sep 2021 00:00:00 +0000 Sustainability enhancement in machining of DTC titanium alloy through integrated impact assessment of various lubrication strategies https://spast.org/techrep/article/view/2793 <p>Machining difficult-to-cut materials like Ti-6AL-4V by conventional methods is characterized by various negative environmental and social impacts, leaving a burden on the environment. Researchers are investigating several potential solutions to this problem; however, due to stringent environmental conditions imposed by the government, it is vital to develop a sustainable machining solution. The word "sustainability" refers to the unit process, which is long-term viable from an economic, environmental, social, and quality point of view. Furthermore, because production and operations managers need to know how the machining process contributes to sustainability, the necessity to measure the sustainability of machining activities has been recognized. As a result, this study presents a novel paradigm for evaluating the impact of machining operations from an economic, environmental, and product perspective, which measures the Machining operation's sustainability. The milling process is the focus of this study due to its frequent application in complex industrial jobs. The novel MQL cutting oil is a newly developed vegetable-based, chlorine-free, high viscosity, no-smoke cutting oil used for machining.</p> <p>The goal of this work is to compare dry machining, flood cooling and MQL for sustainability. A compressive impact assessment of each of the lubrication strategy has been done, and a methodology based on Heron's formula [1] is proposed in the study to assess the impact of a Machining Operation. The face milling operation is considered, and the machining parameters speed 1000rpm, feed 0.06mm/ tooth and depth of cut 0.8mm was kept constant for all the lubrication strategies. The experimental setup is shown in fig 1. Various responses were measure corresponding to different lubrication strategies and given in table 1. For measurement of response, all the equipment used was calibrated before measurement.</p> <p>Considering experimental results, the impact scores for each lubrication strategy and each impact category were assigned with lower is better criteria on 10 point scale where ‘0’ representing best and ‘10’ representing worst performance. The various impact factors selected for the study are shown in fig 2. The scores are assigned with reference to [8]. The scoring values based on various criteria are given in table 2. An extensive survey of [2-10] has been done to arrive at the scoring criteria and calculation methodology.&nbsp; This research is unique because it proposes a methodology for an impact assessment that otherwise a major challenge in quantifying the Impact Indicators. As the lower is better criteria is used, the MQL is found sustainable with a low overall impact score of 27.6 compared to the dry and flood cooling strategy. Dry machining is characterized with an impact score of 77.37, and flood cooling, which is performed worst compared to the other two, is characterized with a high impact score of 118.80.</p> <p>It was found that dry machining is environment friendly, but it is characterized by high tool wear, high surface roughness, increased machining temperature, and high energy consumption. Therefore, it performs worst from an economic and product point of view. Flood cooling, on the other hand, has the highest negative impact on the environment as well as it is a costly process and characterized by moderate values of tool wear and roughness; therefore, the Minimum Quantity Lubrication(MQL) has emerged to be sustainable and environmental friendly without compromising product quality as it uses very small quantity(150ml/hr) of cutting oil which is sprayed in cutting zone with high-pressure air results in low machining temperature, roughness, tool wear and energy consumption.</p> <p><strong>Fig.1.</strong> Experimental Setup for Dry cutting, flood cooling and MQL Strategy.</p> <p><strong>Fig.2.</strong> Various Impact factors considered for study.</p> <p>&nbsp;</p> <p>Table 1. Measured response (output) values for different lubrication Strategies.</p> <table> <tbody> <tr> <td width="120"> <p><strong>Strategy</strong></p> </td> <td width="120"> <p><strong>Ra</strong><strong>(μ)</strong></p> </td> <td width="120"> <p><strong>Tool Wear(mm)</strong></p> </td> <td width="120"> <p><strong>Machining Temperature(</strong><strong>◦</strong><strong>K)</strong></p> </td> <td width="120"> <p><strong>Specific Energy Consumption(J/mm<sup>3</sup>)</strong></p> </td> </tr> <tr> <td width="120"> <p><strong>Dry</strong></p> </td> <td width="120"> <p>0.510</p> </td> <td width="120"> <p>0.3932</p> </td> <td width="120"> <p>493</p> </td> <td width="120"> <p>420.12</p> </td> </tr> <tr> <td width="120"> <p><strong>Flood Cooling</strong></p> </td> <td width="120"> <p>0.473</p> </td> <td width="120"> <p>0.1734</p> </td> <td width="120"> <p>462.6</p> </td> <td width="120"> <p>265.34</p> </td> </tr> <tr> <td width="120"> <p><strong>MQL</strong></p> </td> <td width="120"> <p>0.238</p> </td> <td width="120"> <p>0.0796</p> </td> <td width="120"> <p>429.2</p> </td> <td width="120"> <p>185.74</p> </td> </tr> </tbody> </table> <p>&nbsp;</p> <p>Table 2. Scoring for various Impact factors.</p> <p>&nbsp;</p> <table> <tbody> <tr> <td colspan="2" width="208"> <p><strong>Impact Category/ Strategy</strong></p> </td> <td width="50"> <p><strong>Dry</strong></p> </td> <td width="71"> <p><strong>Flood</strong></p> </td> <td width="115"> <p><strong>MQL</strong></p> </td> </tr> <tr> <td rowspan="3" width="104"> <p><strong>Product</strong></p> </td> <td width="104"> <p>Ra(SRI)</p> </td> <td width="50"> <p>8</p> </td> <td width="71"> <p>4</p> </td> <td width="115"> <p>2</p> </td> </tr> <tr> <td width="104"> <p>EMI</p> </td> <td width="50"> <p>5</p> </td> <td width="71"> <p>7</p> </td> <td width="115"> <p>3</p> </td> </tr> <tr> <td width="104"> <p>PPI</p> </td> <td width="50"> <p>8</p> </td> <td width="71"> <p>6</p> </td> <td width="115"> <p>3</p> </td> </tr> <tr> <td rowspan="3" width="104"> <p><strong>Environment</strong></p> </td> <td width="104"> <p>EI</p> </td> <td width="50"> <p>2</p> </td> <td width="71"> <p>8</p> </td> <td width="115"> <p>4</p> </td> </tr> <tr> <td width="104"> <p>OHI</p> </td> <td width="50"> <p>2</p> </td> <td width="71"> <p>8</p> </td> <td width="115"> <p>3</p> </td> </tr> <tr> <td width="104"> <p>CRDI</p> </td> <td width="50"> <p>2</p> </td> <td width="71"> <p>9</p> </td> <td width="115"> <p>4</p> </td> </tr> <tr> <td rowspan="3" width="104"> <p><strong>Economic</strong></p> </td> <td width="104"> <p>TCI</p> </td> <td width="50"> <p>7</p> </td> <td width="71"> <p>5</p> </td> <td width="115"> <p>3</p> </td> </tr> <tr> <td width="104"> <p>CSII</p> </td> <td width="50"> <p>2</p> </td> <td width="71"> <p>8</p> </td> <td width="115"> <p>4</p> </td> </tr> <tr> <td width="104"> <p>ECI</p> </td> <td width="50"> <p>9</p> </td> <td width="71"> <p>5</p> </td> <td width="115"> <p>3</p> </td> </tr> </tbody> </table> Prasad Jadhav, R Deivanathan Copyright (c) 2021 Prasad Jadhav, R Deivanathan https://spast.org/techrep/article/view/2793 Sun, 17 Oct 2021 00:00:00 +0000 LINEAR STATIC STRESS ANALYSIS ON A NOSE LANDING GEAR https://spast.org/techrep/article/view/1314 <p>One of a city's important – and damaging – obligations to search out determine street illumination: On average large towns throughout the planet, ignition can account for 10%–38% of the total generated power bill (NYCGP 2009). Because of allure clever relevance for business-related and friendly stability, the path upon which travel occurs ignition may happen a specifically urgent matter for public officials fashionable underdeveloped countries. Every year, inefficient ignition wastes a many of money, and distressing making light creates an unpredictable state of affairs in one's life for the brightest star. Energy-efficient electronics and design can considerably lower the cost of street ignition; these provisions for the future can remove or humiliate the need for new production plants, providing funds for strength mixture of liquid and another substance for people reside aloof places. These cost savings concede possibility, in addition, to enable society to extend path upon which travel occurs lighting to a new region, by that improving ignition chance in depressed money earned by work or investments and additional underserved areas. Furthermore, changes in fashionable ignition quality and the incident of help can help to improve the protection from harm of two together vehicles and person traveling on foot. A well-created strength-efficient path upon which travel occurs illumination system endure admitting users to often over water without knowledge accompanying good visibility, protection from harm, and indulgence while lowering person's spirit and vigor use and expense and improving the surroundings’ characteristic. Poorly designed illumination method, in another way, can cause poor perceptibility, light dirtiness, or both. Street illuminations happen frequently poorly build and assert (like, there exist many consumed-out lamps) and uses outdated ignition electronics, consuming very large amounts of strength and financial resources while repeatedly failing to transfer superior natural lighting. According to the Bureau of Energy Efficiency, India's gross strength custom for public lighting fashionable 2007-2008 happen 6,131 million kWh, based on Central Electricity Authority enumeration.</p> Shaik Khajayasif, ASHOK KUPPUSAMY Copyright (c) 2021 Shaik Khajayasif, ASHOK KUPPUSAMY https://spast.org/techrep/article/view/1314 Wed, 06 Oct 2021 00:00:00 +0000 Comparative Study on Performance Evaluation and Thermal Analysis of Automotive Radiator using CFD Analysis https://spast.org/techrep/article/view/2622 <p aria-level="2"><span data-contrast="auto">A radiator is a type of heat exchanger that is used to transfer&nbsp;the&nbsp;heat energy&nbsp;between two mediums.&nbsp;In an automobile radiator, the coolant is circulated&nbsp;through the&nbsp;water&nbsp;jackets&nbsp;around the engine&nbsp;to&nbsp;absorb&nbsp;the excess&nbsp;heat.&nbsp;It is designed to transfer heat from the hot coolant that flows through it to the air blown through it by the fan.&nbsp;The radiator provides a high surface area for better dissipation of heat from the coolant.&nbsp;Most modern cars use&nbsp;aluminium&nbsp;radiators.&nbsp;In the present research work,&nbsp;a comparative&nbsp;study on performance and the thermal analysis of the automotive radiator&nbsp;(Aluminum&nbsp;alloy 6061)&nbsp;has been&nbsp;analysed&nbsp;by two methods, one is finite difference method and the other is&nbsp;thermal resistance concept.&nbsp;Alongside the&nbsp;numerical parametric studies also&nbsp;been&nbsp;carried.&nbsp;In the&nbsp;first step,&nbsp;i.e.&nbsp;the&nbsp;performance evaluation, the radiator is installed into a test-setup and the various parameters including mas flow rate of coolant, inlet coolant temperature&nbsp;are&nbsp;varied&nbsp;and&nbsp;annalysed. Also, a comparative analysis between the coolants is also evaluated. One of the coolants used is water and the other is a mixture of water and propylene glycol (C3H8O2) where it is mixed in a ratio of 2:3 (40:60) for use. In&nbsp;the second step,&nbsp;i.e.&nbsp;the&nbsp;thermal&nbsp;analysis, the&nbsp;CFD analysis on a radiator&nbsp;is carried out at different mass flow rates as well as&nbsp;with and without&nbsp;louvered fins&nbsp;to&nbsp;analyze&nbsp;the heat transfer rate.&nbsp;From this research output, the automobile radiator&nbsp;shows the&nbsp;better results in various thermal properties&nbsp;while using the water as coolant compared to&nbsp;propylene glycol&nbsp;on different working temperatures.</span><span data-ccp-props="{&quot;201341983&quot;:0,&quot;335551550&quot;:6,&quot;335551620&quot;:6,&quot;335559731&quot;:720,&quot;335559738&quot;:40,&quot;335559739&quot;:0,&quot;335559740&quot;:276}">&nbsp;</span></p> <p aria-level="2"><span data-contrast="auto">Keywords</span><span data-contrast="none">:&nbsp;</span><span data-contrast="auto">Thermal Analysis;&nbsp;Automobile&nbsp;Radiators;&nbsp;CFD analysis;&nbsp;Heat&nbsp;Exchanger;&nbsp; Coolant</span><span data-ccp-props="{&quot;201341983&quot;:0,&quot;335559738&quot;:40,&quot;335559739&quot;:0,&quot;335559740&quot;:259}">&nbsp;</span></p> JAYASHANKAR K V, G. ADITHYA SANKAR , KISHAN. V, SENTHUR PRABU.S Copyright (c) 2021 JAYASHANKAR K V, G. ADITHYA SANKAR , KISHAN. V, SENTHUR PRABU.S https://spast.org/techrep/article/view/2622 Sun, 17 Oct 2021 00:00:00 +0000 CFD ANALYSIS OF THERMAL BARRIER COATED TURBINE BLADE https://spast.org/techrep/article/view/1184 <p>Daily produce, effective power gridiron preparation, part maintenance, evaluate part assurance, and secure facility movement all benefit from temporary load forecasts. There exist other methods to predict temporary load, but it bear been found that the point succession approach exists the most within the realm of possibility and hands over the ultimate accurate forecast. The Autoregressive (AR) approach of your temporal length of event or entity's existence order reasoning for brief-term load forecast for Tamilnadu (India) load data exist talk over with another fashionable our research report. For forecasting 4 to 6 hours in front or advance of, the event Autoregressive yields better results.</p> <p><strong>&nbsp;</strong></p> Owen Donald , ASHOK KUPPUSAMY, Freeman Ndossi Copyright (c) 2021 Owen Donald , ASHOK KUPPUSAMY, Freeman Ndossi https://spast.org/techrep/article/view/1184 Fri, 24 Sep 2021 00:00:00 +0000 CRACK PROPAGATION ANALYSIS OF AN AIRCRAFT STRUCTURE https://spast.org/techrep/article/view/2370 <p>The life of an aircraft depends mainly on the specific usage of the aircraft. The manufacturer defines a lifetime for the general usage of the aircraft. But with the specific usage of the aircraft, the aircraft structure may fail prematurely or sometimes may have a lifetime exceeding the manufacturer specified limit. Fatigue plays a significant role in crack growth in aircraft structures. Besides, the Structures may also suffer from corrosion damage and wear defects. The proper maintenance and scheduled test intervals can avoid sudden failure. Therefore, the inspection interval has to become shortened. Several models are identified for the purpose of analyzing fatigue crack propagation and the NASGRO model is selected as the most suitable model for this purpose. The most critical structural components of the aircraft structure are identified and analyzed using this model. A mathematical relationship is developed to predict the flight cycles to the failure of these structures. Then the structural integrity of the aircraft is revalidated based on this calculation.</p> Aneena Praveen N, ASHOK KUPPUSAMY Copyright (c) 2021 Aneena Praveen N, ASHOK KUPPUSAMY https://spast.org/techrep/article/view/2370 Fri, 08 Oct 2021 00:00:00 +0000 Comparative study on Thermal and Structural Analysis of Perimetric Disc Brake using ANSYS https://spast.org/techrep/article/view/2679 <p>In current times, the focus of the automotive industry has not only been innovation in terms of speed and efficiency but also greatly on passenger and vehicle safety. This present study comprises a comparative Thermo-Structural coupled analysis of a perimetric type brake rotor with different materials and cut patterns. Both parameters of the material and cut pattern greatly affect the braking performance of the brake. The braking system of a vehicle is of paramount importance since it is responsible for absorbing the kinetic energy of the vehicle and thus bringing it to rest. A brake disc is needed to generate sufficient frictional torque with the help of frictional force produced due to the brake pads. The frictional torque transmitted to the wheels via the hub should be equal to the torque generated by the traction force to lock the wheels. The rotors were subjected to a temperature load, and the temperature distribution was analysed using cooling parameters. The steady-state temperature of the brake rotor will be greatly affected by the different material and cut patterns, which would further affect the deformation and stresses induced in the disc due to the forces applied on it. The materials selected for the analysis are chosen by applying the concepts of material selection by Ashby Chart. On the perimetric rotor designs, static structural and thermal stress analyses were performed in ANSYS to analyze and compare the stress and deformation pattern of the rotors under extreme loads. For both static structural and thermal stress analysis, finite element analysis is used. In the derivation of the heat equations and force calculations on the brake rotor, parameters such as mass, velocity, tire dimension of the vehicle have been taken into account and CAD models are prepared in SolidWorks. There is also an attempt to recommend the ideal combination of material and cut pattern for disc brake rotors that result in low-temperature variation across the rotor, less deformation, and minimal von mises stress.</p> Satvik Kandregula, Prateek Yash, Gautam Batra, Anirudh C.V.S, Suhail Khan M N, S. Senthur Prabu Copyright (c) 2021 Satvik Kandregula, Prateek Yash, Gautam Batra, Anirudh C.V.S, Suhail Khan M N, S. Senthur Prabu https://spast.org/techrep/article/view/2679 Fri, 22 Oct 2021 00:00:00 +0000 GPS ORBIT DETERMINATION FOR GLACIER HEIGHT MONITORING SATELLITE https://spast.org/techrep/article/view/1312 <p>Glacier height is determined from the range and orbit height of the satellite. The Range (R) is measured between the satellite and the surface of glacier using a space-borne altimeter. And the satellite orbit height (H) is measured from the reference ellipsoid using Global Positioning System (GPS). The difference of orbital height and the altimeter range (H-R) is termed as the glacier height 'h'. Accuracy of the glacier height depends on the precise measurement of both orbital height and altimeter range. The orbital height measured using GPS is accurate compared to all the other tracking systems available. The optimal estimate of the satellite position is obtained using the ODTK tool by setting the mathematical model of the equation of Low Earth Orbit (LEO) satellite and the GPS measurements by applying Kalman filtering.</p> Vinay Pattanashetti , ASHOK KUPPUSAMY, Nishesh Bista Copyright (c) 2021 Vinay Pattanashetti , ASHOK KUPPUSAMY, Nishesh Bista https://spast.org/techrep/article/view/1312 Wed, 06 Oct 2021 00:00:00 +0000 Pre-Tensioned CFRP tubes for improved energy absorption https://spast.org/techrep/article/view/1725 <p>Use of materials like CFRP has shot into prominence to achieve light weight design without compromising on the structural integrity. &nbsp;Circular thin tubes are often employed in passenger cars as energy absorbers to absorb the impact energy during an accident. When such tubes are made of materials like CFRP, it contributes to weight reduction besides leading to reduced fuel consumption. Also due to their lower weight, such tubes shall be capable of absorbing more energy per unit mass compared to metallic designs, which is defined as specific energy absorption capacity (SEA). Pre-Stressing techniques are widely used by Civil engineers across the globe to impart more stress/energy bearing capacity for the structures. Based n pre-stressing principles, Introduction of pre-tension during the fabrication stage for thin CFRP tubular structures has been experimentally studied to validate the applicability of pre-stress concepts for more SEA. The study investigates experimentally the additional advantage prestressing can bring for a CFRP tube in terms of SEA improvement.</p> Venkateswarlu Gattineni Copyright (c) 2021 Venkateswarlu Gattineni https://spast.org/techrep/article/view/1725 Fri, 08 Oct 2021 00:00:00 +0000 Effect of Nano Reinforcement on Aluminium Metal Matrix Composites: A Review https://spast.org/techrep/article/view/449 <p>The developing prerequisite for the item having ease alongside amazing quality has encouraged work towards composites of materials lately. Which are having particular stages and qualities just as better than the parent materials. Metal Matrix composites (MMCs) are continually advancing because of inventive and energizing advances and are broadly utilized just as perceived as a possible material for some mechanical applications in different industry. This examination represents Applications of Aluminum compound primary parts are numerous in vehicles, airplanes and other military components because of their improved properties and solidarity to weight proportions. New class of AMMC are in consideration wide cluster of utilizations in ventures due to great mechanical attributes, ease and light weight. Aluminum Metal Matrix composites likewise can be made through an assortment of methods. By various strategy for the manufacture cycle and by adding the diverse support material, distinctive trademark profile got. Objective of this investigation is to study about of creation measure and different components, which are affecting of Nano Reinforcement on Aluminum Metal Matrix composites.</p> Yashesh Darji Copyright (c) 2021 Yashesh Darji https://spast.org/techrep/article/view/449 Fri, 17 Sep 2021 00:00:00 +0000 Traction Performance Estimation of a Lunar/Planetary Rover Wheel using Finite Element Modelling https://spast.org/techrep/article/view/735 <p>Exploration of outer space such as lunar and mars surface is currently performed using rover vehicles. Sustainable exploration of extra-terrestrial surfaces requires non-destructive exploitation of space resources as well as implementing planetary protection measures to prevent contamination of the other planetary body. Scientific investigations are performed autonomously or semi-autonomously by imparting mobility through mobile rovers which uses motorized wheels for locomotion. This is evident from the missions of various space agencies around the world as from NASA’s Pathfinder mission, Sojourner rover [1], Mars Exploration Rovers, Spirit and Opportunity [2], Mars Science Laboratory, Curiosity rover [3], Mars 2020 mission, Perseverance rover [4]. The wheels for the rovers are designed under severe constraints of mass and volume that is imposed by the requirement of accommodating the rover inside the compact descent/lander module [5]. It should also withstand harsh lunar conditions that includes large temperature range, UV and cosmic radiation, and high abrasion thus influencing material selection of wheels. One of the main design requirements is that the wheels should produce high tractive performance while traversing over different soil (compact, loose, granular etc.), rocks, slopes characteristic of lunar and mars terrain. Previous works on investigating the tractive performance of off-road vehicles can be found in Bekker and Wong [6-7]. In this research, the objective is to estimate the tractive performance of a simple rover wheel using a Finite Element Model (FEM). Other methods or techniques proposed by researchers in the past such as Multibody Dynamics also exist. The FEM method is chosen due to wide-availability of well-known commercial software for Finite Element Analysis (FEA). In the present work, ABAQUS 2020 is chosen as the code for FEA. The wheel is modelled as a rigid body. The soil is modelled with a set of parameters that represent pressure-dependant elasto-plastic cap hardening. The Drucker-Prager/Cap plastic law is followed. The cap is added to the Drucker-Prager model to capture the non-linear compressibility property of the soil. The properties chosen for Drucker-Prager model for the present research are shown in Table 1.</p> <p>{Table 1}</p> <p>First results obtained from FEM simulations will be presented in this paper. The results of von-Mises stress variation of wheel moving over soil is shown in Fig.1.</p> <p>{Fig.1.}</p> <p>This proposed modelling approach helps to determine how quickly the wheel can accelerate without significant slippage. The division of the model into domains is constrained by model definition i.e., all the elements involved in a particular contact interaction must be on same domain. The areas in soil on which wheel has been rolling remembers previous reached stress in the form of pre-consolidation pressure. It contours for the compaction and cap hardening. The pre-consolidation pressure is lower at surface and higher at depth because of soil weight as it leads to higher pressure in depth. A dynamic analysis was used to provide a time history of the interaction and the dynamic behaviour.</p> <p>It was shown from this research it is possible to investigate the effect of changes in soil properties on tractive performance including gravity effects, slip using FEM. It is possible to obtain better results through further mesh refinement. It is possible to predict drawbar pull and obtain input torque versus slippage trends. The obtained FEM results will be finally validated with experimental results obtained from single-wheel testbed [5].</p> <p><strong>References</strong></p> <ul> <li>NASA, “Mars Pathfinder”, Webpage: <a href="https://mars.nasa.gov/mars-exploration/missions/pathfinder/">https://mars.nasa.gov/mars-exploration/missions/pathfinder/</a>, accessed 15-09-2021.</li> <li>NASA, “Mars Exploration Rovers”, Webpage: <a href="https://mars.nasa.gov/mer/">https://mars.nasa.gov/mer/</a>, accessed 15-09-2021.</li> <li>NASA, “Mars Curiosity Rover”, Webpage: <a href="https://mars.nasa.gov/msl/home/">https://mars.nasa.gov/msl/home/</a>, accessed 15-09-2021.</li> <li>NASA, “Mars 2020 Mission Perseverance Rover”, Webpage: <a href="https://mars.nasa.gov/mars2020/">https://mars.nasa.gov/mars2020/</a>, accessed 15-09-2021.</li> <li>P. Pruiksma, J.A.M. Teunissen, G.A.M. Kruse, M. Van Winnendael, “Tractive performance modelling of the ExoMars Rover wheel design on loosely packed soil using the Coupled Eulerian Lagrangian Finite Element Technique”, In Proceedings of ASTRA 2011, ESA/ESTEC, 13 April 2011. Webpage: <a href="http://robotics.estec.esa.int/ASTRA/Astra2011/Papers/02A/FCXNL-11A06-2138699-2-2138699pruiksma.pdf">http://robotics.estec.esa.int/ASTRA/Astra2011/Papers/02A/FCXNL-11A06-2138699-2-2138699pruiksma.pdf</a>, accessed 20-08-2021.</li> <li>G. Bekker, “Theory of Land Locomotion: The Mechanics of Vehicle Mobility”, The University of Michigan Press, Ann Arbor, USA, 1956.</li> <li>Y. Wong, “Theory of Ground Vehicles”, 4<sup>th</sup> edition, John Wiley and Sons, Inc., 2001.</li> <li>Shoop S.A., “Finite Element Modeling of Tire–Terrain Interaction”, US Army Corps of Engineers, Engineer Research and Development Center, Report ERDC/CRREL TR-01-16, 2001. Webpage: <a href="https://apps.dtic.mil/sti/pdfs/ADA398076.pdf">https://apps.dtic.mil/sti/pdfs/ADA398076.pdf</a>, accessed 15-09-2021.</li> </ul> Aashish Gyawali, Darshan Prajapati, Dawit Solomon, Dhruv Dineshkumar Mehta, Rohan Dharmendrakumar Patel, Dr. Aravind Seeni Copyright (c) 2021 Aashish Gyawali, Darshan Prajapati, Dawit Solomon, Dhruv Dineshkumar Mehta, Rohan Dharmendrakumar Patel, Dr. Aravind Seeni https://spast.org/techrep/article/view/735 Wed, 15 Sep 2021 00:00:00 +0000 DESIGN FOR ASSEMBLY (DFA) OF HAND TROLLEY https://spast.org/techrep/article/view/2551 <p>The use of Hand Trolleys plays an important role in all construction and manufacturing industries. Hand Trolleys are designed and manufactured according to various governing features like load capacity, materials and ergonomic design. The fundamental objective of a hand trolley is to provide a hassle-free mode of transporting heavy objects from one location to another.</p> <p>It is a well-known fact that the demand for consumer products increases day by day and the technological advancements and development in the industries contribute to the increase in the demand for products in the market. To meet this demand, production facilities must be expanded and the speed of manufacturing and assembly must be increased. The hand trolleys that exist today are not well optimized for assembly. Therefore, the assembly times are huge and hence this drives up the cost of production drastically.</p> <p>The focus of this work will be to redesign a hand trolley to fully optimized it with respect to manual assembly by following all the DFA guidelines. This should help reduce assembly costs and improve production rate of the hand trolley. This will in turn decrease the overall production cost per product as factory workers will spend less time assembling one hand trolley and hence productivity will increase.</p> <p>Design for Assembly (DFA) evaluation is an accurate and systematic methodology to evaluate how well a product is designed from an assembly point of view. Each component must be conceptualized and designed in such a way that it aligns and mates efficiently and easily. This includes the design and processing of the component in a specific manner with respect to shape, size, tolerances, and surface finish. A component designed for assembly leads to a significant decrease in assembly time as well as in the total cost to assemble the product.</p> <p>A hand trolley often is an assembly of several individual parts. Every individual part has to be planned, designed, and manufactured separately. Generally, the Assembly of the overall finished product is a function of design parameters that incorporate both intensive (material properties) and extensive (physical attributes) properties. Examples of such design parameters include size, shape, flexibility, material compatibility, thermal conductivity, etc. It is easy to see that, when individual components are designed and manufactured with ease of assembly in mind, the result is a significant reduction in assembly time. This results in savings of resources and capital.</p> <p>The redesigning of the hand trolley is done following the specifications and goals set forth, which are to reduce assembly time, trim down the total weight of the assembly, reduce the number of parts used and simplify user operation while still maintaining a high level of safety, comfort and efficiency. The redesigned hand trolley employs new designs not seen or used on hand trolleys today, while still successfully achieving all its objectives.<br>The authors will be designing the hand trolley using Solidworks 2020 software and the DFA evaluation for manual assembly will be conducted using the Boothroyd-Dewhurst DFA method.</p> <p>The expected outcome of our work is a whole new redesigned hand trolley that is as good as or much better than the conventional hand trolley with respect to its primary function of lifting and transporting heavy loads from one location to another. Furthermore, the new redesigned hand trolley will be designed with assembly in mind and by following and employing all DFA guidelines for manual assembly, it will definitely be much easier and quicker to assemble. It is expected that with the increase in the design efficiency of the new design, it will be much easier and simpler to assemble. Hence, the new design of the hand trolley will be much cheaper to produce and therefore driving the overall cost of production per product down.</p> Nevan Nicholas Johnson, Swapnil Sanket Copyright (c) 2021 Nevan Nicholas Johnson, Swapnil Sanket https://spast.org/techrep/article/view/2551 Sun, 17 Oct 2021 00:00:00 +0000 The DEVELOPMENT OF REAL TOUCH VIRTUAL WORLD INTERACTIVE GLOVES https://spast.org/techrep/article/view/2214 <p><strong>Abstract </strong></p> <p>This virtual reality is an interactive computer generated experience taking place within a simulated environment. A person using virtual reality equipment is able to look around the artificial world, move round it. The visual manifestation of the real world is not sufficient to truly immense oneself in the virtual world. He must be able to connect with the environment, feel its differences and react to the changes around himself and a device that produces this magic touch is real touch. We created a virtual environment in unity and we learned to implement our design in unity software using c+. Virtual reality experience is achieved using the trinus software meshed over the unity. Our dynamic hand moments are captured by a leap motion control sensor which consists of two cameras and three infrared LEDs. These track infrared light with a wavelength of 850 nanometers, which is outside the visible light spectrum. The coverage area of the sensor which we chose is 2 feet above the controller, by two feet wide on each side (150-degree angle), by two feet depth on each side (120-degree angle). Also we 3D printed the sensor mount, which is mounted over the headset in order to obtain a better coverage of the sensing area. Finally, Coin vibrator is used over the fingertips which aids for the achieving cutaneous sensation of touch. The mechanism of the glove will achieve both kinesthetic and cutaneous sensation thus reproducing the feeling of touch in the virtual world.</p> <p>Keywords: Virtual reality, Real touch, Unity software, 3D printing, Coin vibrator and Glove.</p> PRABU D Copyright (c) 2021 PRABU D https://spast.org/techrep/article/view/2214 Sun, 03 Oct 2021 00:00:00 +0000 Design Optimization of 3-DOF Hybrid Manipulator https://spast.org/techrep/article/view/1292 <p>Studies related to reachable workspace, inverse kinematics, and best dimensions of 3-DoF (Degrees of Freedom) Hybrid Manipulator (HM) are presented in this paper. This mechanism possesses both serial and parallel links. A third revolute joint is added in the five-linkage structure having two actuated revolute joints. The third revolute joint is added in such a way that its axis should pass through the axes of the two actuated revolute joints. This produces a structure called a hybrid mechanism consisting of parallel and serial links.<br>A Hybrid mechanism consists of both serial and parallel links. Serial mechanisms are arranged as cantilever type of kinematic arrangement due to this arrangement serial mechanism suffers from lack of stiffness and positioning errors on the other hand parallel mechanisms have higher stiffness but possess less workspace. These drawbacks can be overcome by the hybrid manipulator. The accuracy and stiffness of the hybrid manipulator are found to be better than serial manipulators. X.Z. Zhang [1] introduced a parallel mechanism based on two kinds of 3-UPU hybrid serial-parallel manipulators. Each of the 3-UPU constitutes one base, one platform, and three limbs. Tian chunxu et al., [2] developed a spatial mechanism. The end-effector of this mechanism possesses two rotations and two translations, and the development of this novel hybrid mechanism helps to develop a more complicated mechanism. Hamid Rakhodaei [3] in his Ph. D work, discussed the design of a new configuration of a hybrid parallel robot with 9-DoF.<br>Fig.1 shows a five-bar, revolute (R)-coupled linkage, closed-chain type hybrid parallel manipulator. The θ1 and θ2 are the actuated joint variables, and the x, y coordinates of the revolute center P are the Cartesian variables. One more degree of freedom is imparted to the manipulator of Fig. 1 by adding one revolute joint to the above five bar closed chain manipulator. The fixed link AB of the above manipulator is coupled to the base of a new manipulator with the help of a revolute joint. This arrangement allows the two-DoF manipulator to rotate about line AB. Thus three-DoF hybrid manipulator is obtained as shown in Fig. 2</p> <p>The inverse kinematics analysis is implemented for obtaining the joint positions of the hybrid manipulator. The reachable workspace of the manipulator is found using inverse kinematic equations and finally considering Global Conditioning Index (GCI) [4, 5] as the objective for optimization of the Hybrid Manipulator using Genetic Algorithms (GA’s)[6, 7].</p> <p>Results and Discussion</p> <p>For L0 = 0.6m, L1 = 0.8m and L2 = 0.5m the workspace of the Hybrid manipulator having 3-DoF is shown in Fig. 3.For the above Workspace (Fig. 3) the mean value of GCI is 0.69, whereas for the maximum value of GCI = 0.51 which is free from singularities and the minimum value of GCI is 1.2225e-04 which is closer to singularities.<br>The optimal dimensions of the 3-DoF Hybrid Manipulator are obtained using GA. In these, the design variables are L1 and L2 and the objective function is Maximum GCI. The GA is converged for 79 number of iterations and the obtained optimal dimensions are L1 = 0.494, L2 = 0.939 and GCImax = 0.6034. The solution convergence of GA is shown in Fig.4.</p> <p><br>Conclusions<br>In this paper, the joint angles of the manipulator are obtained with the help of inverse kinematic analysis of the 3-DoF hybrid manipulator. The hybrid manipulator’s workspace is found by rotating the link AB about Y-axis to 180o. The mean GCI for the said workspace is 0.69, whereas the maximum value of GCI = 0.51 which is free from singularities, and the minimum value of GCI is 1.2225e-04 which is closer to singularities. Optimal dimensions of 3-DOF hybrid manipulator are found using GA by considering GCI as objective. The obtained optimal dimensions are L1 = 0.494 m, L2 = 0.939 m and the maximum value of objective function is GCI = 0.6034.<br><br></p> <p><img src="https://spast.org/public/site/images/sanjay_darvekar/mceclip0.png"><img src="https://spast.org/public/site/images/sanjay_darvekar/mceclip1.png"></p> <p>Fig.1. A 2 DoF Manipulator&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Fig.2. Schematic diagram of 3-DoF Hybrid Manipulator</p> <p><img src="https://spast.org/public/site/images/sanjay_darvekar/mceclip2.png">&nbsp; &nbsp; &nbsp; <img src="https://spast.org/public/site/images/sanjay_darvekar/mceclip5.png"></p> <p>Fig.3. Workspace of 3-DOF Hybrid&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Fig.4. Convergence of GA</p> Sanjay Darvekar Copyright (c) 2021 Sanjay Darvekar https://spast.org/techrep/article/view/1292 Thu, 30 Sep 2021 00:00:00 +0000 Design and Analysis of Lunar Rover Wheels using Finite Element Modelling https://spast.org/techrep/article/view/1091 <p>The initiative to explore the moon has always been a necessity for humans to promote seep space exploration. Exploration requires surface mobility, and whether on Earth or on Moon, sensible tires are required for locomotion and traversing the surface. Exploring an unknown extra-terrestrial surface is a demanding task. This paper presents a survey on the lunar environment, the design requirements for a lunar rover wheel. Three different rover wheel designs illustrated in Fig.1. are analyzed using Finite Element Modelling (FEM). They are the Lunar Roving Vehicle’s (LRV) wheel used in the manned Apollo-17 mission [1], the Lunokhod-1 wheel used in the robotic Luna-17 mission [2], and a new design called the Tweel design to be used for future NASA missions [3]. The challenges in each of the following designs have been identified and a review on what small changes can be made in existing designs have been composed.</p> <p>Tires making contact with the surface of the moon must be able to withstand the moon’s harsh environment such as extreme temperature fluctuations, low gravity, absence of atmosphere, lunar dust, thick regolith, exposure to the cosmic and solar radiation, etc [4]. The wheel is also required to have as much terrainability as possible on the lunar surface which includes soft regolith and slopes to boulders/steps and craters to achieve robust teleoperation.</p> <p>The LRV’s wheel used four massive 81.8 cm diameter, 23 cm wide tire comprised of zinc coated steel strands attached to an aluminium hub with titanium chevrons fixed to the contact area to provide traction. Though upon inspection these wheels showed intensive wearing at the wire connection because of the abrasive lunar soil. The wire mesh was the best choice for its application back in time but it may be insufficient in achieving future lunar missions. The Lunokhod-1 wheel configuration consisted of 8 rigid rim wire mesh wheels with bicycle-kind spokes and steel cleats for traction. The wheel diameter was 51 cm and the width was 20 cm. It operated on slopes as much as 32 degrees. Being the first rover to ever discover floor out of earth it had little drawbacks and proved greater than expected. The Michelin lunar wheel or Tweel maintains flexibility and constant ground pressure, permitting the vehicle to manoeuvre through loose soil and craters. Tweel consists of a composite reinforced tread band, connected to a flexible (deformable) wheel via rectangular, polymer spokes. The resulting mechanical structure provides weight-carrying ability, shock absorption, ride comfort, rolling resistance and mass just like gas tires while adding suspension-like characteristics that greatly improve handling. But several enhancements to the current wheel have to be made, some of that are reducing the noise vibration and so forth.</p> <p>The analysis of the different wheel models is performed through Finite Element Modelling. It is done to provide information on how they perform in the lunar soil.</p> <p><strong>References</strong></p> <ul> <li>David A. Kring, “Lunar Mobility Review”, 2006. Webpage: <a href="https://www.lpi.usra.edu/science/kring/lunar_exploration/briefings/lunar_mobility_review.pdf">https://www.lpi.usra.edu/science/kring/lunar_exploration/briefings/lunar_mobility_review.pdf</a>, accessed 20-09-2021.</li> <li>Vivake Asnani, Damon Delap, and Colin Creager, “The Development of Wheels for the Lunar Roving Vehicle”, Glenn Research Center, Cleveland, Ohio. Webpage: <a href="https://core.ac.uk/download/pdf/10551874.pdf">https://core.ac.uk/download/pdf/10551874.pdf</a>, accessed 20-09-2021.</li> <li>Marisa Orr, Development of A Finite Element Model to Predict the Behavior of a Prototype Wheel on Lunar Soil, PhD Thesis, Clemson University. Webpage: <a href="https://core.ac.uk/download/pdf/268633524.pdf">https://core.ac.uk/download/pdf/268633524.pdf</a>, accessed 21-09-2021.</li> <li>Grant H. Heiken, David T. Vaniman, Bevan M. French, “Lunar Source Book – A User’s Guide to the Moon”, Cambridge University Press, 1991.</li> </ul> Brinda Bhattarai, Chetasvani Dutta, Shri Lakshmi K.M., Deeptha A.S., Kavya Nair, Dr. Aravind Seeni Copyright (c) 2021 Brinda Bhattarai, Chetasvani Dutta, Shri Lakshmi K.M., Deeptha A.S., Kavya Nair, Dr. Aravind Seeni https://spast.org/techrep/article/view/1091 Tue, 21 Sep 2021 00:00:00 +0000 Experimental study on flow past stepped cylinder with different step configuration https://spast.org/techrep/article/view/1127 <p>The flow of fluid behind a blunt body such as an automobile is difficult to compute due to the unsteady flows. The wake behind such a body consists of unordered eddies of all sizes that create a large drag on the body. In contrast, the turbulence in the thin boundary layers next to the streamlined bodies of aircraft and fish creates only weak disturbances of flow. The flow past a two-dimensional cylinder is one of the most studied aerodynamics. It is relevant to many engineering applications. Flow past a stationary vertical circular cylinder is carried important analyses in a wind tunnel test setup which contributes to aerodynamics, construction of multi-storage buildings, multi feet towers, bridges, marine and ocean engineering research for better design. In the present study, a number of stepped cylinders are considered for finding drag and lift of the cylindrical surface with the help of a pitot-static tube and U-tube manometer sensors with water as manometric fluid. The manometers are connected to the circumferential of the stepped cylinder to found the pressure profile and wake created along with the cylinder. The cylinders design with different configurations of steps along with their vertical distance. The stepped cylinders will be considered for the experimental study with Reynolds numbers ranging from 10000 to 100,000. The predicted results are drag and lift coefficients, centre of pressure, pressure profile along with the cylinder and intensity of the wake in the opposite side of the stepped cylinders with the variation of flow and geometrical parameters like shape and position of the stepped, diameter, and height. The estimated result will be compared with the existing literature database which will show a good agreement.&nbsp;</p> Santosh Panda Copyright (c) 2021 Santosh Panda https://spast.org/techrep/article/view/1127 Fri, 24 Sep 2021 00:00:00 +0000 A literature Review on Orifice as a flow measuring device https://spast.org/techrep/article/view/1161 <p>Flow measurement is an important parameter for experimental analysis as well as to control the processes in the industry. To measure the flow rate there are various traditional flow measuring devices are used i.e. nozzle, venturimeter, Pitot Tubes, Turbine Meters, Vortex Shedding Meters, Coriolis Meters, Magnetic Resonance Meters and orifice meter. An orifice meter is one of the flow measuring devices that is more popular among all the instruments because of its simple design, less cost and easy manufacturing, less skill for fit in a flow passage to pressure drop and determine the discharge in single and multi-phase flow. The flow measurement carries an important role in a research laboratory, petroleum, energy, nuclear, mining, chemical processing, and food industries to regulate the flow. In a multiphase flow problem such as oil and gas industry, chemical and processing industry wellhead chokes are used to control the production of oil and control, but due to significant error in the flow measurement orifice is used as an alternative device. The present work provides a brief idea about single hole orifice consider for various applications which will helpful for the betterment of orifice design and analysis. The review paper will be studying different types of an orifice such as round hole orifice, square hole edge, elliptical, sector, perforated, two-stage orifice, Eccentric, Segmental, Quadrant, Conic, etc. The orifice is also classified as the thin and thick orifice as per the plate thickness. The review papers also give basic information of the numerical, visualization and experimental studies for different applications on orifice to determine the pressure drop, flow profile, and determination of coefficient of discharge on the variation of geometrical and flow parameters.</p> Santosh Panda Copyright (c) 2021 Santosh Panda https://spast.org/techrep/article/view/1161 Fri, 24 Sep 2021 00:00:00 +0000 Slip effects on unsteady MHD free convective flow of Rivlin- Ericksen fluid in the presence of heat source/sink https://spast.org/techrep/article/view/1576 <p>In the present work, an investigation on MHD flow of viscoelastic fluid of Rivlin Ericksen type across a semi-infinite plate in the presence of heat source/sink under free convection is conducted. The plate is moving with constant velocity subjected to periodic suction along with slip conditions. Further, the free stream velocity is taken of oscillatory in nature. The transport equations governing the flow are solved using perturbation analysis. The solutions obtained for the required fields viz. velocity, temperature and concentration which characterizes the flow are discussed graphically for varying situational parameters appeared in the flow. The presence of heat source/sink in the vicinity of considered fluid has significant effect on the velocity near the plate. Further, the drag at the plate, Nusselt and Sherwood number are evaluated for varying situational parameters which are compiled in the tabular format.</p> <p>So, to study the above problem the literature is reviewed where many researchers have contributed towards different behaviour of Rivlin Ericksen fluid model under various imposed conditions. The MHD flow of Maxwell’s or Oldroyd’s fluid model of viscoelastic fluids across an infinite plate under various effects has been investigated by numerous researchers due to their relative importance in different areas of engineering and industry. These applications involve the geothermal extraction process, paper manufacturing, petroleum drilling, MHD accelerators, irrigation processes, food processing and many more. But another class of viscoelastic fluids which is represented by the Rivlin Ericksen fluid model is also explored by some researchers due to its relevant implications in the chemical industry and geophysical fluid dynamics. On considering the Rivlin Ericksen fluid model, many problems of viscoelastic fluids have been modelled under various imposable conditions which carries their remarkable importance in the fields of science, technology and industry. Jordana and Purib [1] presented the exact solutions and some limiting and special cases for Stokes' first problem for a Rivlin-Ericksen fluid of second grade in a porous half-space taking into account the isothermal conditions using Laplace transform techniques. Noushima et al. [2] investigated the unsteady behaviour of Rivlin Ericksen viscoelastic flow of electrically conducting fluid across an infinite vertical plate of porous nature subjected to the constant suction and variable permeability. Varshney et al. [3] explored the rotatory Rivlin Ericksen visco elastic flow of electrically conducting fluid past a moving infinite surface given exponential acceleration and constant suction while considering the constant heat and mass flux in the flow. Uwanta and Hussain [4] discussed the variable suction effect on the hydromagnetic flow of Rivlin – Erickson fluid past a vertical infinite porous plate due to free convection. Banyal and Sharma [5] presented their analysis using linearized stability theory and normal mode analysis to the Rivlin Ericksen viscoelastic fluid subjected to the uniform vertical rotation. Ravi Kumar et al. [6] inspected the effects of heat transfer on an electrically conducting Rivlin Ericksen viscoelastic fluid across a semi-infinite vertical porous plate moving with a constant velocity while taking into account the time-dependent suction and free stream velocity. Mishra [7] inspected the heat and mass transfer effects on MHD fluctuating flow of viscoelastic Rivlin Ericksen fluid across a porous plate and studied the impact of magnetic number, viscoelastic parameter and porosity parameter on velocity and temperature profiles. Reddy et al. [8] investigated the Soret and Dufour effects on MHD flow of Rivlin- Ericksen fluid past a semi-infinite vertical plate under free convection while taking constant mass flux using numerical analysis. Malleswari [9] inspected numerically the influence of magnetic field applied transversely on laminar flow of viscoelastic Rivlin Ericksen fluid past a semi-infinite vertical plate in the porous medium due to free convection and diffusion.</p> <p>Numerous research problems on slip flow effects for different flow types have been attempted by researchers in recent years.&nbsp; The use of slip flow phenomenon can be seen in the filtration processes using nanofibers and high-speed flights. Pande and Goudas [10] investigated the Rayleigh problem for hydromagnetic flow across a porous wall subjected to time-dependent suction in slip flow regime and discussed the velocity and drag behaviour at the wall through graphs. Further, the participation of Morques [11], Hayat et al. [12], Singh and Devi [13], Mishra et al. [14], Sahoo [15], Garg et al. [16] can be seen in the literature towards the study of slip effects on various flow types across some geometrical bodies under different imposing conditions. Recently, Hussaini [17] investigated the steady profiles of rotatory Rivlin Ericksen flow across an infinite plate in a porous medium with slip behaviour at the bounding plate.</p> <p>Heat generation/ absorption in the presence of heat source/sink has another phenomenal aspect in heat transfer problems of several flows. So, under the consideration of the heat source/sink effects in various flows, Chamkha and Khaled [18] investigated numerically the heat generation or absorption phenomenon for hydromagnetic flow past an inclined plate using similarity methods. Later, Chamkha [19] presented his studies on the unsteady behaviour of MHD flow across a permeable plate due to heat source/sink. Das and Panda [20] examined the heat source effect on MHD stratified fluid across a moving plate of a porous kind under slip conditions. Further, Das et al. [21] investigated the heat source effect on MHD flow across a porous plate of oscillating behaviour due to free convection with slip flow effects. However, Osman et al. [22] inspected analytically the MHD flow along with an inclined porous plate under chemical reaction and radiation effects with heat source/sink using the Laplace transformation method. Under motivation of the above studies, the present investigation is performed on the unsteady free convective flow of Rivlin Ericksen fluid model which is passing across a flat plate subjected to periodic suction having slip conditions in the presence of heat source/sink.</p> <p>&nbsp;</p> Deepti . Copyright (c) 2021 Deepti . https://spast.org/techrep/article/view/1576 Fri, 08 Oct 2021 00:00:00 +0000 FUEL SYSYTEM DESIGN AND VALIDATION FOR UAV https://spast.org/techrep/article/view/1307 <p>The main goal is to develop a simple fuel system for a UAV (Unmanned Aerial Vehicle), as well as to check and validate whether the simulation and theoretical values are within an acceptable range. The Fuel system of Lakshya is studied as a baseline reference model. Lakshya is a remotely piloted high-speed target drone system which is used to perform discreet aerial reconnaissance of battlefield and target acquisition. Flowmaster is a 1-Dimensional (1-D) Computational Fluid Dynamics (CFD) tool which is used for modeling and analyzing fluid mechanics in simple and complex piping structures as well and duct components of any scale. The fuel system of Lakshya is modeled in Flowmaster software with some modifications. The losses across each component are calculated theoretically and recorded. The losses are simulated on Flowmaster and the results are analyzed. The benefits of using Flowmaster simulation software are highlighted.</p> Aneena Praveen N , ASHOK KUPPUSAMY Copyright (c) 2021 Aneena Praveen N , ASHOK KUPPUSAMY https://spast.org/techrep/article/view/1307 Fri, 01 Oct 2021 00:00:00 +0000 Different Swirl Angle On Nox Generation Of 2d Swirl Burner CFD Analysis https://spast.org/techrep/article/view/1795 <p>The strategy for presenting little scope disturbance in the fuel utilizing a swirler in gas turbine combustors are ongoing patterns. In this study, a numerical 2D model has been created to simulate the stream and burning in a gas turbine combustor. The qualities of the model are; consistent, violent, two dimensional and twirling stream. Stream examples, blending and temperature in a whirl burner with changing geometry have been examined. The Primary objective is to locate the best whirl plot for least NOx outflows for the burning applications. The standard k–ε model of choppiness has been utilized to anticipate the low and medium whirl streams. It is discovered that standard k–ε model of choppiness predicts the low whirls very well yet at higher swirl streams results are poor. The recreations indicated that the NOx decrease is less due to swirler with a fixed vane point of 45º. The attributes of swirl streams are assessed by methods for size of the distribution which may help better blending of fuel and air for complete burning. In this segment, we introduce results and we contrast them and the test information. In this review, we examine forecasts of the mass part of all species. At last, we break down the expectations of mean temperature. The affectability of the expectations to the decision of k-ε demonstrate (Cε3 = 0.79), substance active system and the EDC display for turbulence-science cooperation is examined. The lessened system of was already approved on the premise of non-premixed flares.[7]</p> <p>At that point, the system executed into the CFD code Fluent, utilizing the technique for coordinated connection chart and Quasi Steady State Assumption. The instrument was joined into the Fluent by the method for a client characterized work that uses the subroutine (Define-Net-Reaction-Rates) to figure the species response rates, which are bolstered into the turbulence-ignition display. The FORTRAN subroutine is connected to Fluent through the (DNRR) contention large scale. This full scale is known as the EDC model and used to process the shut turbulent species response rates. The EDC utilizes the FORTRAN responses rates as a contribution to the turbulent response rates.[1, 2]</p> <p>This subroutine, which is good with FLUENT, is indicated in the client characterized capacity and returns the molar creation rates of the species given the weight, temperature, and mass portions. The Under-unwinding components are diverse for various factors, shifting from 0.3 to 0.9. The vitality condition is extremely hard to unite, so the component is taken as 0.4. The gulf turbulent detail strategy is 'power and length scale'. Turbulence force is 10% and turbulence length scales are 0.008 m for fuel and 0.0175 m for air. We start by contrasting the computational cost of Hyer component and the worldwide instrument display [8], as far as the normal CPU (execution) time per time step. In this segment, we introduce results and we contrast them and the test information. In this review, we examine forecasts of the mass part of all species. At last, we break down the expectations of mean temperature. The affectability of the expectations to the decision of k-ε demonstrate (Cε3 = 0.79), substance active system and the EDC display for turbulence-science cooperation is examined. The lessened system of was already approved on the premise of non-premixed flares.</p> <p>At that point, the system executed into the CFD code Fluent, utilizing the technique for coordinated connection chart and Quasi Steady State Assumption. The instrument was joined into the Fluent by the method for a client characterized work that uses the subroutine (Define-Net-Reaction-Rates) to figure the species response rates, which are bolstered into the turbulence-ignition display. The FORTRAN subroutine is connected to Fluent through the (DNRR) contention large scale. This full scale is known as the EDC model and used to process the shut turbulent species response rates. The EDC utilizes the FORTRAN responses rates as a contribution to the turbulent response rates.</p> <p>This subroutine, which is good with FLUENT, is indicated in the client characterized capacity and returns the molar creation rates of the species given the weight, temperature, and mass portions. The Under-unwinding components are diverse for various factors, shifting from 0.3 to 0.9. The vitality condition is extremely hard to unite, so the component is taken as 0.4. The gulf turbulent detail strategy is 'power and length scale'. Turbulence force is 10% and turbulence length scales are 0.008 m for fuel and 0.0175 m for air. We start by contrasting the computational cost of component and the worldwide instrument display [9], as far as the normal CPU (execution) time per time step.</p> ASHISH SHRIVASTAVA Copyright (c) 2021 ASHISH SHRIVASTAVA https://spast.org/techrep/article/view/1795 Fri, 08 Oct 2021 00:00:00 +0000 Investigation on the Mechanical Properties of Epoxy Polymer Reinforced with Various Nano materials https://spast.org/techrep/article/view/771 <p>S-Glass fiber composite has steady and regular epoxy resin substance with SiO2Nano particles and high grating element. This composite is layered unidirectional S-Glass fiber (0˚/90˚/0˚/90˚) stacked up into a composite at 1:1 ratio of Fiber and Matrix volumes and 0% wt. of Nano, 0.5% wt. of Nano and 1% wt. of Nano SiO<sub>2</sub>, Si-C, Graphene Particles added to the Epoxy.&nbsp; The investigational characterization of S-Glass Fiber/Epoxy with SiO<sub>2</sub>, Si-C, Graphene, Nano-particles composite material and its conduct is essentially important for time of mechanical properties data for examination, plan and production of supplementary parts. Also, the experimental information can be adequately implied sharpen and have imperative repercussions for ideal blueprint of composites.</p> NAGAKALYAN SOMESULA, M RAMALINGA REDDY, M RAMALINGA REDDY Copyright (c) 2021 NAGAKALYAN SOMESULA, M RAMALINGA REDDY, M RAMALINGA REDDY https://spast.org/techrep/article/view/771 Sat, 18 Sep 2021 00:00:00 +0000 DESIGN AND ANALYSIS OF MEDIUM UTILITY AIRCRAFT LANDING GEAR https://spast.org/techrep/article/view/114 <p>The landing gear is one of the critical components in aircraft and it is known that the<br>majority of aircraft accidents happen due to failure of landing gear and also it is a complex<br>dynamic system of several degrees of freedom.Accordingly for safety reasons the root<br>causes of these failures must be well identified in order to avoid future accidents. Stress<br>analysis is one of the important work in finding structural safety and integrity of a structure. In<br>this work, initially the main landing gear strength calculation based on ultimate loads is<br>carried out analytically. The stress failure exist in the intermediate zone between the support<br>bearing of the wheels and the clamping of the axle to the nose of the aircraft. with the aim of<br>determining the causes of the failure, a material analysis was performed The margin of<br>safety for both major components such as axle, piston, cylinder, yoke as well as minor<br>components such as toggle link, toggle fork, stub fork, bolts is determined. In FEA analysis<br>the geometric model of MLG designed in CATIA is imported into Hyper Mesh. The model is<br>meshed using tetrahedron element in Hyper Mesh. Also the line model is created from<br>geometrical model and meshed in Hyper Mesh using 3D beam elements as mentioned in<br>Fig.1. The stress analysis is carried out in Abacus. The displacement analysis done under<br>different loading conditions as in table 1 to 3. Both analytical and FEA results for stresses<br>are compared and it is find out that the factor by which the FEA and analytical results are<br>varying. The margin of safety calculated by analytical work based on ultimate loads gives<br>positive values as expected. The landing gear strength calculations by both analytical and<br>FEA shows the maximum stress for different load conditions based on ultimate loads are<br>well within the ultimate strength of that material mentioned in fig.2. It may encounter various<br>vibration modes due to design features or frictional characteristics of brake.</p> R Karthikeyan R; R Sridhar; Panneer Selvam; R Jiniraj Copyright (c) 2021 R Karthikeyan R; R Sridhar; Panneer Selvam; R Jiniraj https://spast.org/techrep/article/view/114 Mon, 23 Aug 2021 00:00:00 +0000 CFD investigation of solar air heater provided with an artificial roughness of a boot shape, reversed boot shape and their combination in a rectangular duct https://spast.org/techrep/article/view/1871 <p>Solar air heater has less Heat transfer enhancement. The Prandtl number and Reynolds numbers is a major subject of research over the years also. It is the explain of the thermal hydraulic performance of the Artificial roughness of boot shape, reversed boot shape. It has already known that boot shape, reversed boot shape inserted in the smooth rectangular channel to improve the heat transfer rate as well as thermal efficiency. This enhancement is, however, accompanied by a considerable increase in the friction factor. Thermal performance of a solaria airy heater concerns with the heat transfer process within the collector. The result of smooth duct operated under same condition to discuss the enhancement in heat transfer on account of artificial roughness. In the present investigation of the project heat transfer enhancement in three dimensional rectangular duct for combination of boot shape and reversed boot shaped have been completed using ANSYS WORKBENCH 14.0. The solar air heater is used in, distillation, air conditioning, water heating, space cooling and heating, cooking, industrial drying and agriculture, and air conditioning, refrigeration, power generation etc. &nbsp;In the present work roughness in the form of boot shape and reversed boot shape rib duct of a solar air heater on the absorber plate. The Nusselt number and Friction factor for the same was find and the corresponding values are compared. The Reynolds number in the range of&nbsp;&nbsp; 2000-18000 and relative roughness pitch 7-12. CFD software completes the working of the solar rectangular channel. CFD (Computational Fluid Dynamics) is use in the optimization of roughness of solar air heater and analysis software.</p> GAURAV Copyright (c) 2021 GAURAV https://spast.org/techrep/article/view/1871 Fri, 08 Oct 2021 00:00:00 +0000 Formulation of alcohol based microemulsion fuel and its utilization in compression ignition engine https://spast.org/techrep/article/view/2064 <p>Emulsion fuel is progressively gaining world attraction due to its eco-friendly nature by promoting reduced emission levels.&nbsp; In view of the concern over automobile emission increasing at an alarming rate, a new light to an alternate green fuel capable of reducing emission at reasonable cost is most essential. In this context used cooking oil (UCO) emulsion fuel is looked into as a possible alternative. UCO emulsion fuels are prepared by blending UCO with polar low molecular weight alcohols. Surface tension between polar phase (alcohol) and non-polar phase (oil) is reduced by adding surfactant. Conversion of waste to energy helps us to maintain a cleaner environment and reduces the dependence on conventional fuel. Emulsions are highly temperature sensitive and their stability need to be monitored critically[1]. Along with the addition of surfactant mechanical agitation and ultra sonification process are being used for better mixing at molecular level and thereby an increase in the stability of the emulsion is being achieved[2]. But microemulsion is found to be thermodynamically stable and is formed spontaneously without the application of external agitation mechanisms[3]. The absence of complicated chemical reactions and the easiness of formation makes emulsification a potential alternative to transesterification process. The process requires optimum use of surfactant for a particular mixture[4].</p> <p>In this study a microemulsion fuel containing diesel, used cooking oil(UCO) and ethanol surfactant mixture(E/S) has been formulated. Fuel characteristics of three stable mixture ratios MF(ES-10) (70% diesel, 20% UCO, 10% E/S), MF(ES-15) (60% diesel, 25% UCO, 15% E/S), MF(ES-20) (50% diesel, 30% UCO, 20% E/S) were evaluated. In comparison to the studies that have been conducted on microemulsion emulsion fuels, here we utilize a&nbsp; short chain alcohol as a surfactant to stabilize the emulsion. Engine test was conducted at constant speed of 600rpm for different loads. Diesel fuel is used as reference for comparison. The ethanol content in the fuel results in a reduction in the in cylinder temperature. This contributes towards a decrease in nitrogen oxide emission. The presence of alcohol also may promote secondary atomization process which will improve the combustion efficiency. On the other hand&nbsp; with an increase in percentage of alcohol content the calorific value of fuel will decrease which tends to reduce the engine output. The break specific fuel consumption of emulsion fuels will be more compared to corresponding biofuels and diesel.</p> <p>Calorific value of microemulsion fuel is less compared to diesel fuel. Kinematic viscosity of emulsion fuel is within the limit prescribed by biodiesel standards. Microemulsion fuel have a lower flash point due to the presence of E/S mixture. The acid number of emulsion fuel is slightly above the limit specified by biodiesel standards ASTM D 6571. Engine test results shows an increase in brake thermal efficiency and specific fuel consumption using microemulsion fuel. 3.5% increase in specific fuel consumption and 2.9% increase in brake thermal efficiency is obtained. Significant reduction in exhaust emissions is observed. NOx emission decreased by 22.3% and smoke emission decreased by 15.2%. Microemulsion fuels can be used as an alternative fuel in diesel engine without engine modification But addition of higher amount of waste cooking oil and E/S increases viscosity, fuel consumption, Acid number and decreases flash point.</p> Deepak B, Mohamed Ibrahim Copyright (c) 2021 Deepak B, Mohamed Ibrahim https://spast.org/techrep/article/view/2064 Fri, 08 Oct 2021 00:00:00 +0000 Design, Fabrication and performance Evaluation of Modified Electric Three Wheeler Vehicle https://spast.org/techrep/article/view/503 <p><span class="fontstyle0">In recent times, electric vehicles (EV) are gaining popularity, and the reasons behind this<br>are many. The most eminent one is their contribution in reducing greenhouse gas (GHG)<br>emissions. , the transportation sector emitted 25% of the GHGs produced by energy related<br>sectors. EVs, with enough penetration in the transportation sector, are expected to reduce that<br>figure, but this is not the only reason bringing this century old and once dead concept back to life,<br>this time as a commercially viable and available product. As a vehicle, an EV is quiet, easy to<br>operate, and does not have the fuel cost associate with conventional vehicles. The statics of the<br>vehicle population and pollution by vehicles, need of alternative option for IC engine vehicles is<br>stated. Number of two wheelers and four wheeler are most in compare to all other categories of<br>the vehicles in India and especially in BHOPAL City which has been chosen as an area of study<br>leads to find replacement option for fuel powered two-wheeler vehicles. Electrical energy usage<br>for vehicle is been selected as it is non-polluted energy source for vehicle. Whereas other fuels<br>are fully or partially pollution generated vehicles .The main motive of the work is (1) Study of<br>existing electrical three wheeler vehicle. (2) Examining, Drawback &amp; shortcomings of battery<br>three wheeler vehicle. (3) Propose new modified design. (4) Fabrication of the three wheeler<br>electric vehicle and its performance testing. (5) Designing customized modifications as per the<br>service need</span> </p> rajendra ahirwar Copyright (c) 2021 rajendra ahirwar https://spast.org/techrep/article/view/503 Sun, 19 Sep 2021 00:00:00 +0000 Investigation of Anodized Aluminium Heat Sink using ANSYS Simulation https://spast.org/techrep/article/view/2655 <p>A heat sink is a heat exchanger that transfers heat from an electrical or mechanical</p> <p>component to a fluid by providing an efficient path for heat to be transferred and dissipated.</p> <p>In this research paper, the model of the heat sink (6060 Aluminum Alloy) is made by using</p> <p>Auto Desk Fusion 360 software to build the components. With the help of Ansys software the</p> <p>thermal analysis of the heat sink (Heat transfer simulation to visualize the whole heat</p> <p>exchanging process)</p> <p>is carried out by considering the alloy 6060 Aluminum with and without</p> <p>anodized. The main</p> <p>reason we chose the Aluminum alloy is due to its lower cost, good</p> <p>thermal conductivity,</p> <p>lightweight and the fact it can easily be extruded. From this research</p> <p>output, the anodized</p> <p>heat sink has showed improved results in various thermal properties</p> <p>compared to the non-anodized heat sink. Not only limited to that but it also improves the</p> <p>corrosion resistance, wear resistance and electrical isolation of the heat sink. Therefore the</p> <p>results will support better for the heat sink manufacturer using the anodized 6060 Aluminum</p> <p>alloy in near future.</p> Ashwanthram Gokule Rajendran, Saubhagya Sooradas, Prakhar Chandrakar, Senthur Prabu Copyright (c) 2021 Ashwanthram Gokule Rajendran, Saubhagya Sooradas, Prakhar Chandrakar, Senthur Prabu https://spast.org/techrep/article/view/2655 Mon, 18 Oct 2021 00:00:00 +0000 Wheat straw natural fiber used as Brake pad Reinforcement Polymer composite as asbestos free brake friction material https://spast.org/techrep/article/view/2253 <p>The awareness towards the eco-friendly materials has increased the demand of natural fibers. The natural fibers have many advantages over the other materials like short growing time, easy availability, cheap, eco-friendly with good mechanical properties. W.H.O. has announced that trending material have many sides effect to environment and to human being. Asbestos has been already proven cause of many cancers. In this research Wheat straw natural fiber has used in brake pad as a brake friction material. The different percentage of Wheat straw 5-20% was used to develop new brake pad samples. The results of physio-mechanical properties reveal that tensile Modulus, ultimate compressive strength, impact energy, flexural strength showing good performance at 5 % polymer composites matrix, and ultimate tensile strength, shear strength and proof showing good performance at 10% fibers contents in brake pad composites. Thermal stability for Wheat straw fibers composites increase with increases the fiber contents.</p> sushil kumar, Naresh Kumar; Kamal Kashyap Copyright (c) 2021 sushil kumar, Naresh Kumar; Kamal Kashyap https://spast.org/techrep/article/view/2253 Thu, 07 Oct 2021 00:00:00 +0000 Solid State Fabrication Methods for Aluminum Metal Matrix Composite- A Review https://spast.org/techrep/article/view/1290 <p class="Els-Abstract-text" style="tab-stops: center 233.85pt;">The application of metal matrix composites(MMCs) in automobile, aerospace, construction, marine and defense sector grown exponentially in recent years. Aluminum metal based matrix composite (AMMC) components has low density, high strength to weight ratio and excellent wear resistance properties as compared to monolithic materials. The versatility of these types of composite is their mechanical properties customize by matrix material and reinforcement agent. Research is required to develop cost effective production process for Aluminum Metal Matrix Composites based on specific requirement by the industry. The emphasis of this article is to study various production methods currently used for AMMCs.</p> Yashesh Darji Copyright (c) 2021 Yashesh Darji https://spast.org/techrep/article/view/1290 Thu, 30 Sep 2021 00:00:00 +0000 Analyses of Rear Landing gear of Unmanned Aerial Vehicles using Carbon Fibre Composites https://spast.org/techrep/article/view/2634 <p>Unmanned aerial vehicles (UAVs) are being used for numerous applications. To name a few, mapping and surveying, payload delivery, weather monitoring&nbsp;and&nbsp;aerial photography are some of the applications of UAVs. A suitable landing gear is required in an UAV to support the weight of aircraft and to dissipate the impact energy during landing of the aircraft. The landing gear should have a high strength to weight ratio.</p> <p>In this research article the main focus is on structural design and thermal analysis of the back landing gear of UAVs by using different materials (Carbon Fibre Composites) which is having higher strength, good stiffness, anti-corrosion as well as anti-fatigue properties and resistance to environment &amp; wear. Alongside it also meeting the need for low cost to weight ratio which can used as a substitute to conventional used material Al 6061-T6 for the manufacturing of landing gear. This study illustrates the design, composite prepost, followed by the numerical analysis of the landing gear. 3D modelling of the landing gear is done by using SOLIDWORKS followed by stacking the layers in the required orientation and thickness using ACP Prepost. Finite element analysis using ANSYS is then done to analyse stresses developed during landing of the aircraft and to compute the total deformation.</p> <p>From this research output, Composite materials have a Young’s Modulus approximately two times to that of aluminium alloys with having half the weight of it.&nbsp;Pre impregnated carbon fibre (prepreg) was used over wet layups as it uses 15% less resin (epoxy) which decreases the manufacturing costs and also has uniform distribution of resin unlike wet layups. Also the excess resin in the wet layup causes brittleness and reduces the overall properties of the carbon fibre.&nbsp;Both Unidirectional (UD) and Woven carbon fibres are analysed.</p> <p>The preliminary analysis for an impact speed of 5m/s shows that the all the substitute materials considered are providing better results than Al 6061-T6 in terms of total deformation and equivalent Von-Mises Stress.</p> <table> <tbody> <tr> <td width="106"> <p>S.No</p> </td> <td width="397"> <p>Material</p> </td> <td width="141"> <p>Total Deformation (mm)</p> </td> <td width="124"> <p>Von Mises Stress (MPa)</p> </td> </tr> <tr> <td width="106"> <p>1</p> </td> <td width="397"> <p>Al 6061-T6&nbsp;(Conventional Material)</p> </td> <td width="141"> <p>14.502</p> </td> <td width="124"> <p>141.03</p> </td> </tr> <tr> <td width="106"> <p>2</p> </td> <td width="397"> <p>Ti-6Al-4V</p> </td> <td width="141"> <p>8.59</p> </td> <td width="124"> <p>140.87</p> </td> </tr> <tr> <td width="106"> <p>3</p> </td> <td width="397"> <p>Epoxy Carbon Fibre UD 395GPa - Prepreg - (0-90° stacking)</p> </td> <td width="141"> <p>9.816</p> </td> <td width="124"> <p>268.34</p> </td> </tr> <tr> <td width="106"> <p>4</p> </td> <td width="397"> <p>Epoxy Carbon Fibre UD 395GPa - Prepreg - (0-&nbsp;45°-90°-135° stacking)</p> </td> <td width="141"> <p>14.65</p> </td> <td width="124"> <p>107.69</p> </td> </tr> <tr> <td width="106"> <p>5</p> </td> <td width="397"> <p>Epoxy Carbon Fibre Woven 395GPa - Prepreg - (0-90° stacking)</p> </td> <td width="141"> <p>11.501</p> </td> <td width="124"> <p>148.88</p> </td> </tr> </tbody> </table> Hardik Shukla, Sai Sravan Yarlagadda, Akshay Badagabettu, Sai Santosh Thatikonda, Senthur Prabu S Copyright (c) 2021 Hardik Shukla, Sai Sravan Yarlagadda, Akshay Badagabettu, Sai Santosh Thatikonda, Senthur Prabu S https://spast.org/techrep/article/view/2634 Sun, 17 Oct 2021 00:00:00 +0000 Study on Measurements of Flame Geometry by Schlieren and Direct Light Photography https://spast.org/techrep/article/view/2309 <p>As schlieren imaging continues to be used around the globe, many studies have also been done to modify the classic technique into something simpler yet reliable for research purposes. Despite its success throughout the centuries, the schlieren imaging has many limitations with one of them being its intricacy when setting it up, making it rather time consuming. Other limitations include the cost, portability, and field-of-view [1-2]. For years, researchers have come up with various new methods deriving from the classic schlieren to overcome those limitations. These modified setups are then called as “synthetic schlieren” as they stem and are altered from the classic setup, but their purpose does not deviate from the original, which is to visualize flows that are impossible for the human eyes to see [3]. Unfortunately, most of the past works revolved around overcoming the general problems of the classic technique and not enough experiment has been performed to assess the chance of substituting schlieren imaging with direct light imaging for the purpose of measuring flame geometry. In this study, the experiment focuses on direct light imaging – a simple setup that uses modern cameras. With how simple it is, it is hoped that the setup will be able to lift certain burdens that are faced by many researchers who uses the classic setup, if the experiment is deemed to be a success. The objective of this study is to compare the effectiveness of direct light imaging in capturing the propagation of flame as compared to schlieren imaging. Both the schlieren and direct light method are experimented to accomplish the objective of comparing the performance of direct light imaging to schlieren imaging. With how much cameras have advanced over the years, it is anticipated that flame images captured using direct light imaging will be decent enough for geometry analysis. Furthermore, the focus of this study is on the geometry of the flame, which is visible to cameras. Thus, this further increases the possibility of a positive outcome from the experiment. For direct light imaging, the setup is as simple as using a camera and a black screen. The setup is done in two settings – dark room and bright room – for the comparison of clarity in the images captured. For schlieren imaging, the setup is only done in one setting as the brightness of the room will not affect the clarity of the images due to the light source used in the setup. The type of flames that are focused on in this study are candle, stove, lighter, and flame ignited with hand sanitizer. Each flame type is fuelled by different fuel to observe the influence it has on the flame. The results between the setups are compared and it is shown that the direct light setup is as competent as the schlieren imaging in its ability to capture high-quality flame images. The results continue to show that flame analysis with direct light imaging is possible, and this could be the beginning of modern camera in the field of flame geometry research.</p> Olive Uyang David Ngau, Shaharin Anwar Sulaiman Copyright (c) 2021 Olive Uyang David Ngau, Shaharin Anwar Sulaiman https://spast.org/techrep/article/view/2309 Thu, 07 Oct 2021 00:00:00 +0000 A review on recent developments in the fabrication of superhydrophobic surfaces for sustainable industrial applications https://spast.org/techrep/article/view/2433 <p>Wettability of solid surface is regarded as one of the most significant properties, owing to the wide range of applications that rely on this property. The contact angle (CA) of a water droplet on a surface is a simple way to describe the wettability of a surface. Superhydrophobic surfaces (SHS) are those with very high-water contact angles, often more than 150<sup>0</sup>. Special attention should be paid to these surfaces, because of characteristics such as anti-sticking and anti-contamination [1] and self-cleaning [2]. These characteristics are advantageous in a variety of industrial and biological applications, because of their highly non-wetting characteristic including self-cleaning, drag reduction, oil-water separation, anti-corrosion, anti-reflective clear coatings, and anti-soiling architectural coatings. The wettability of a solid surface is usually understood to be a consequence of two main factors: surface roughness and surface chemistry. The surface energy is determined by the chemical composition of the surface, which has a significant impact on its wettability. However, altering the surface chemistry alone will not determine the superhydrophobic state; both conditions must be present at the same time.</p> <p>&nbsp;</p> <p>The superhydrophobic character of the surface is also influenced by the surface topology. Surface roughening enhances the superhydrophobic condition by increasing the solid-liquid interface. Various techniques for fabricating SHS have been discovered by manipulating these two characteristics, including Chemical etching [3], electrospinning [4], Sol-gel [5], electrochemical deposition [6], Template deposition [7], Spray coating [8] methods, etc.</p> <p>&nbsp;</p> <p>Many natural species, such as lotus leaves [9], water strider's legs [10], cicada orni’s wings [11], and others, have a water contact angle greater than 150<sup>o </sup>and sliding angle that are less than 10<sup>o</sup>. These surfaces are water repellent because water droplets roll off at a modest tilt angle (slide angle), eliminating contaminants from the surface (self-cleaning). As shown in the literature, a significant amount of study has recently been dedicated to the production and theoretical modelling of superhydrophobic surfaces [12-13]. &nbsp;The main goal of this review is: (a) to discuss about the superhydrophobic effect and how it works as a self-cleaning mechanism; (b) to provide the most current advancements in preparing techniques in a methodical manner; (c) to investigate the possible use of superhydrophobic coatings, and (d) to review theoretical models to provide insights for superhydrophobic surface preparation. Here, we will concentrate on the most recent advances in superhydrophobic surface research (the past four years).</p> <p>&nbsp;</p> <p>This review is divided into five parts. The first part provides an overview of the superhydrophobic effect. The second part covers the fundamental principles for superhydrophobic surface preparation as well as the properties of natural superhydrophobic surfaces. The third part gives a thorough review of superhydrophobic surface preparation methods, with an emphasis on the manufacturing process, materials, and structures. The fourth part covers recent advances in theoretical modelling, while the fifth section provides an overview of superhydrophobic surface possible sustainable industrial applications. Finally, a personal viewpoint on the fundamentals of superhydrophobic surface manufacturing is presented.</p> Kashif Azmi Copyright (c) 2021 Kashif Azmi https://spast.org/techrep/article/view/2433 Tue, 12 Oct 2021 00:00:00 +0000 Mr Integrated fuzzy AHP and fuzzy GRA approach for multi objective optimization of directionally rolled multi stage deep drawn micro cups https://spast.org/techrep/article/view/349 <p>In the present work, the working of an multi stage multi cup deep drawing process by micro cups with four factors, Clearance, Die Radius, and Coefficient of Friction, were considered to be the controllable parameters, each at three levels, for monitoring the maximum thinning rate of three responses, namely Resultant Tool Force (N), Spring back (µm), Forming limit Curve (%), Max thinning rate. An eight-stage micro deep drawing system was designed and developed to manufacture a micro cup. The copper strip blank was rolled with 250 % deformation with the Strain rate of XXX, the initial thickness from 6 to 0.18mm to obtain different grain sizes by uni directionally rolled strips in such a way to study the grain size effect on the deformation behavior and thickness variation of the quality micro part. &nbsp;Response surface methodology using Central composite design, Quadratic model, Randomized, 20 runs has been utilized to determine the optimum level of process parameters so that they are least affected by noise factors for obtaining a robust design of the parameters. The process was simulated using Altair INSPIRE form, an explicit Finite Element with actual material test data.</p> <p>&nbsp;Acknowledging the limitation this proposed method can determine optimal setting of controllable parameters for one output or response at a time, integrated fuzzy AHP for determining the weights and fuzzy GRA methods for determining the rank were used in the scheme of multi-response parametric optimization. The rank 1 simulation trial were confirmed with the validation by experiment.</p> Sundar Sivam Copyright (c) 2021 Sundar Sivam https://spast.org/techrep/article/view/349 Fri, 17 Sep 2021 00:00:00 +0000 NoaH treated Banana natural fiber used as Reinforcement Polymer composite: as asbestos free brake friction material https://spast.org/techrep/article/view/1405 <p>The focus of researchers is on eco-friendly materials these days. Natural fibers are in trending because of its eco-friendly nature, moreover that these materials have also good mechanical properties. Natural fibers are using these days in much application due to its good mechanical properties. In this research banana fiber natural fiber has been used in brake pad as a brake friction material. The different percentage of banana fiber 5-20% was used to develop new samples. It has been investigated in the current study that the 10% banana fiber composites showing better results in mechanical properties like proof stress, shear strength and tensile strength than that of others banana fiber composites while flexural strength, impact energy and compressive strength showing improved results for 10% banana fiber-based composites. 5% banana fiber composites have showed lowest value of wear [1.50g]. Thermal stability for Banana fiber-based composites was found to be increased with increases percentage of banana fiber in composite matrix. 20% banana fiber composite has showed highest value [5.84] of oxidation index.</p> sushil kumar, Naresh Kumar; Kamal Kashyap Copyright (c) 2021 sushil kumar, Naresh Kumar; Kamal Kashyap https://spast.org/techrep/article/view/1405 Wed, 06 Oct 2021 00:00:00 +0000 The Numerical Investigations of Heat Transfer in a Double Pipe U-Tube Heat Exchanger Equipped with Twisted Tape and Cut Twisted Tape Inserts https://spast.org/techrep/article/view/424 <p>With rising demand for natural resources, an 'energy crisis' is imminent in the foreseeable future. Yet our ability to move to renewable and novel sources of energy relies on it. Energy consumption as an area of critical interest has gained a lot of momentum over the last few decades. Innovations in heating or cooling in industrial processes have resulted in improved energy efficiencies, and extended lifespan of process equipment, while at the same time making economic sense in general. Heat exchangers have found their prominence in many industrial applications such as chemical and petrochemical processing, food manufacturing, power generation, heat recovery systems, and nuclear plants, to name just a few [1–4]. Heat exchangers are applied to facilitate heat transfer between hot fluid and cold fluid streams. The walls of the heat exchanger tubes facilitate the conduction and convection mechanism to transfer thermal energy from hot fluid to cold fluid. Over a long span, considerable progress has been made in the improvement of heat transfer times and thermal efficiencies in a heat exchanger. The methods that are employed to increase convective heat transfer coefficients are classified as active and passive techniques [5–7]. The former technique requires the use of an external energy source to enhance heat transfer efficiency. The latter, however, is dependent on the modification of geometry by the addition of various types of innards which induces turbulence within the system – thereby increasing the efficacy of heat transfer. Turbulence is further propagated due to the presence of swirling, vortical, and secondary flows which are a consequence of geometry modification [8]. To date, a variety of tube inserts have been employed in a number of studies, some of which include twisted tapes, coiled wires, helical screws and conical screws.</p> <p>In their work, Chang et al. (2007) [9], have experimentally investigated the effect of broken twist tape inserts with various twist ratios on the heat transfer characteristics of a heat exchanger. Nusselt number increased by 1.28–2.4 times and 6.3–9.5 times for the broken twist tape inserts as compared to the continuous twist tape and bare tube without inserts, respectively. A higher swirling motion was reportedly induced in the presence of broken twist tape as compared to the continuous twist tape inserts. Similarly, the Fanning friction factor ratios were higher for the broken twist tape as compared to the continuous twist tape inserts. Rahimi et al. (2009) [10] have investigated the effects of classic and modified twisted tape inserts on heat transfer characteristics using experimental analysis and Computational Fluid Dynamics (CFD) simulations. It was reported that for a wide range of Reynolds number, higher Nusselt number and thermal-hydraulic performance was noticed with the modified inserts - these parameters increased by 31% and 22% respectively as compared to the classic internals. Numerical simulations revealed an increase in the turbulent intensities close to the wall in the presence of modified internals as compared to the classic type. In another numerical study, Tusar et al. (2019) [11] have investigated the effect of the insert’s twist ratio on heat transfer and fluid hydrodynamics. Twist tapes with two twist ratios of 3.46 and 7.6 were analyzed. As expected, the Nusselt number and friction factor augmented with increasing Reynolds number. As compared to the bare tube, the addition of inserts with twist ratio of 3.46 and 7.6 increased the Nusselt number by 20–62% and 10–30%, respectively. Similarly, as compared to the bare tube, friction factor values enhanced in the range of 185–245% and 128–183% with the addition of inserts of twist ratios, 3.46 and 7.6, respectively. Thermal performance factor for twist ratios 3.46 and 7.6 was 0.9–1.2 and 0.95–1.02, respectively.</p> <p>In the current work, CFD modelling is applied to investigate the effect of the addition of inserts in a double pipe heat exchanger. The influence of twisted tape and modified twisted tape inserts on heat transfer characteristics are studied. For the twisted tape and cut twisted tape, an h/d ratio of 3 and a depth of 1 mm cut is considered. Physical parameters such as heat transfer rate, heat transfer coefficient, and pressure drop determined for a range of Reynolds numbers with water as working fluid. The numerical results are validated against experimental results.</p> Raj Kumar Maloth Nayak, Glen DSouza, Swarna M Patra Copyright (c) 2021 Raj Kumar Maloth Nayak, Glen DSouza, Swarna M Patra https://spast.org/techrep/article/view/424 Wed, 15 Sep 2021 00:00:00 +0000 Investigating the air drag energy regenerative system in an electric vehicle using CFD analysis https://spast.org/techrep/article/view/2361 <p>In the current scenario of automobile industry, it is evident that electric vehicles transition occupies a major part in automobile sector. Many automobile giants like BMW, Audi, TATA Motors, etc., are spending millions of dollars into research and development of electric vehicles every year and many of them are planning to go fully electric as early as possible in order to maintain their dominance over the world market. Even with the current technological advancements, many companies still find several challenges of going fully electric. One of the main reasons for this is the range of the electric cars. The current average range of an electric vehicle is around 180 miles and it takes approximately 8 to 10 hours for a car to get fully charged while using standard voltage chargers. This makes EV’s an unfavourable alternative for travelling longer distances. So, this research is to employ a kinetic energy recovery system which uses air drag to recharge the car battery during the vehicle drive. This design concept of the electric car uses the air drag created during the motion of the vehicle to generate electricity through a turbine generator arrangement which is further used to charge the battery. The outer surface of the designed car body contains three air intake vents, which are placed in such a way that they do not affect the aerodynamics of the vehicle. As the vehicle starts moving, air enters the pipeline network through provided vents. This air rotates the twin turbine system which is connected to a generator that converts the mechanical energy into electrical energy, thereby producing the electricity.</p> <p>CFD Air drag velocity analysis, is performed to the designed car model, using Ansys Software in order to test the design efficiency of the vehicle. Streamline surface air flow analysis was conducted over a wide range of air velocities (up to 100km/s) to ensure the validation of the model under extreme conditions. The results obtained were not only promising but also gives a considerable advantage in overcoming the problem of travel range in electric vehicles if implemented practically.</p> M.S.Kiran Karthik, T Aryan Sai Aneesh, Senthur Prabhu Copyright (c) 2021 M.S.Kiran Karthik https://spast.org/techrep/article/view/2361 Fri, 08 Oct 2021 00:00:00 +0000 Investigation of Thermal Behaviour of Cylindrical Lithium-ion Batteries for Electric Vehicle https://spast.org/techrep/article/view/707 <p>With growing concerns over climate change due to automotive emissions, fossil fuel<br>depletion and the increasing price of crude oil, electric vehicles have gained more interest as<br>a mode of transportation. Various electric vehicles have been developed in recent years,<br>including pure electric vehicles (EVs), hybrid electric vehicles (HEVs), and plug-in hybrid<br>electric vehicles (PHEVs). EVs have the capability to reduce the severe threats of energy crisis<br>and environmental pollution. One of the keen focus area in the ongoing development of EVs<br>is their energy storage systems. Mostly lithium-ion batteries of different chemistry and shape<br>factors are being used to make a required capacity of battery pack depending on the<br>applications. Various complicated reaction occurs during charging/discharging of batteries and<br>the thermal behaviour of the batteries are coupled to these reactions. Electrochemical<br>reactions affect the heat generation rate, and higher temperatures further increase the speed<br>of the electrochemical reactions. Adverse operating temperatures can impact battery<br>performance, degradation, and safety. Hence it is become very important to investigate the<br>thermal behaviour of the lithium-ion batteries for different charging/discharging rate and<br>various atmospheric conditions which can further help for designing the better thermal<br>management system in order to achieve the maximum performance of battery pack. Thermal<br>investigation of cylindrical lithium-ion batteries of different chemistry and shape factor is<br>conducted for different charging/discharging rate and atmospheric conditions using numerical<br>technique. The numerical technique includes the determination of surface temperature of<br>battery by solving the energy balance equation using suitable numerical method. The accuracy<br>of numerical techniques is validated using the experimental and simulation techniques.<br>Thermal investigation conducted in this research can help in deciding the operating strategies<br>of battery management system and further in designing the proper thermal management<br>system.</p> RAVINDRA KUMAR Copyright (c) 2021 RAVINDRA KUMAR https://spast.org/techrep/article/view/707 Sat, 18 Sep 2021 00:00:00 +0000 Review on Evolution of robotic arm and its types https://spast.org/techrep/article/view/2489 <p class="Default">In this paper we will see the evolution of robotic arms and how the types were introduced to the world. Due to this there was drastic change in the industry, it brought revolution in the medical field also. Now a days there are many changes in types for surgical system also and they potential towards it. There is a definite change in robotic arms. Robotic arms are used in many applications like household, industry etc. It was first invented in the year 1954 by Geroge Devol.</p> Shanmukh Behere Copyright (c) 2021 Shanmukh Behere https://spast.org/techrep/article/view/2489 Sun, 17 Oct 2021 00:00:00 +0000 Pulsating hydromagnetic flow of Oldroyd-B nanofluid in a vertical channel with entropy generation https://spast.org/techrep/article/view/2523 <p>The magnetohydrodynamic pulsating flow of Oldroyd-B nanofluid in a vertical channel with the thermal radiation, viscous dissipation and Joule heating with entropy generation is investigated in the present study. The influence of Brownian motion and thermophoresis are taken into account. In this investigation, the Buongiorno model is used. The governing coupled partial differential equations are reduced into Ordinary differential equations by help of the perturbation method and numerically solved by using Runge-Kutta fourth order scheme along with shooting method. The impacts of different emerging parameters for velocity, temperature, nanoparticles concentration, heat and mass transfer rate are analysed in detail.</p> <p>The term “nanofluid” refers to a substance in which nonometer-sized rigid particles are suspended in base fluids. Choi [1] was the first propose the development of nanofluid in 1995. The convective heat transfer in nanofluid was investigated by Buongiorno [2]. The author made a two-component, non-homogeneous four-equation equilibrium model in nanofluid. Radhakrishnamacharya and Maiti [3] explored pulsating flow of a viscous fluid in a porous channel with the heat transfer action. Non-Newtonian impacts in steady motion of some idealized elastic-viscous fluids were studied by Oldroyd [4]. Kumar et al. [5] used the Runge-Kutta fourth order technique along with shooting approach to investigate hydromagnetic pulsatile flow of non-Newtonian nanofluid in a vertical channel with porous medium.</p> VENKATESAN G, Subramanyam Reddy A, Srinivas S, Jagadeshkumar K Copyright (c) 2021 VENKATESAN G, Subramanyam Reddy A, Srinivas S, Jagadeshkumar K https://spast.org/techrep/article/view/2523 Sun, 17 Oct 2021 00:00:00 +0000 Biomechanical Analysis of Multi-Material Hip Implant Assembly https://spast.org/techrep/article/view/1156 <p>In present work, a three-dimensional multi-material Charnley’s femoral stem with standard geometry model i.e., 28 mm diameter femoral head and 2 mm thick liner has been developed and analysed for mechanical behaviour like stress, strain and deformation. An axial load of 2.3 kN has been used to analyse for twelve multi-material combinations of CoCr and Ti materials for stem, with three femoral head ceramics materials (alumina, zirconia and ZTA) and UHMWPE for liner. These mechanical parameters are also well validated with previous literature and have been evaluated for investigating the functionality and suitability of biomaterials. Changing the femoral head does not make any significant impact on the mechanical parameters. The preliminary simulation result demonstrates that CoCrMo with Zirconia and UHMWPE demonstrates the most minimum deformation and maximum stress generation. However, CoCrMo leads to modulus mismatch due to its very high modulus. So, implant with less deformation and moderate stress i.e., Ti-6Al-7Nb is preferred over CoCrMo.</p> Tanuj Joshi, Mr. Ravikant Shrama, Dr. Vinod Kumar Mittal, Dr. Vikas Gupta Copyright (c) 2021 Tanuj Joshi, Mr. Ravikant Shrama, Dr. Vinod Kumar Mittal, Dr. Vikas Gupta https://spast.org/techrep/article/view/1156 Fri, 24 Sep 2021 00:00:00 +0000 THE LIQUID COOLED MICROCHANNEL HEAT SINK BASED PELTIER SOLAR ATMOSPHERIC WATER GENERATOR https://spast.org/techrep/article/view/1652 <p>Problems</p> <p>Efficiently of Peltier Is not at Its best, It Is not portable, durability of the body Is still an issue and a forced convection technique Is not viable for smaller heat sinks as there is simply not enough space.</p> <p>How to increase efficiency</p> <p>Maintain the high RH value near dry air vent, Increase the efficiency of Peltier with proper ventilation, that is to make the heat escape easily, to provide more surface area for heat sink to cool down the air more effectively.</p> <p>Advantages</p> <p>Mass of the body is reduced and durability is improved. RH value is maintained with help of dry air vent. A liquid cooled microchannel heat sink can be advantageous as it requires a much smaller space, is suitable for high flux heat dissipation, and offers a higher heat capacity and thermal conductivity when compared to generic convection methods. Use 12V DC battery as an alternative power source.</p> <p>Special features</p> <p>We have chosen aluminium 6061 alloy to build the body. Changed the design of the body (changed angles and shapes to give better result) that is to increase durability. Liquid cooled microchannel heat sink is used without reacting with the body frame. It is also portable with help of 12V DC solar 10W with some restrictions. PWM is used to control fan speed and change voltage for Peltier module.</p> <p>Applications</p> <p>This proposed alternative system will help to solve the water problem in rural areas, especially in the humid climate area like India. We can especially use it in hill stations as the humid conditions is the best. It can be placed in national highways nest mini at toll plaza for free water to the travellers. Can be used them in temples near humid areas.</p> <p>Disadvantages</p> <p>Less uniform flow distribution of the microchannel not only decreases the heat sink’s efficiency by raising local Thermal stress, but also generates high pressure losses between the inlet and the outlet requiring greater pumping Power consumption for operation. It looks too complex to convert 230V 50Hz AC to 12V DC. Risk of short circuit will Increase. Even though portable, it is slight heavy.</p> Mr.Suriya Devalan AR, Dr. E. Vijayaragavan Copyright (c) 2021 Mr.Suriya Devalan AR, Dr. E. Vijayaragavan https://spast.org/techrep/article/view/1652 Fri, 08 Oct 2021 00:00:00 +0000 A review on recent developments in tribology of copper based composite reinforced by 2D material https://spast.org/techrep/article/view/726 <p>Copper based materials find their usage in bearing, ship, aeronautical, medical, electrical and<br>thermal applications. The properties like high ductility, corrosion resistance, thermal and<br>electrical conductivity makes it suitable for wide range of applications. While 2D material like<br>graphene, MoS2, MoSe2, h BN, WS2, etc. are well known solid lubricants which increases the<br>ease of sliding and decreases the wear in turn. This paper highlights the results of different<br>investigations pertaining to the dry sliding wear behavior of copper-based composites<br>containing 2D materials, published in the last decade. In addition, different wear mechanisms<br>and tribo-chemical reactions responsible for decrease or increase in friction are also discussed<br>in detail. The role of microstructural features, tribo-film, transfer-layer, physiochemical<br>reactions, oxidation, electronic work function and temperature in frictional and wear behavior<br>of copper-based composites containing 2D material has not been discussed inclusively<br>elsewhere. This review contains the current trends of research and qualitative facts on layered<br>material reinforced copper-based materials.</p> Hemant Nautiyal Nautiyal Copyright (c) 2021 Hemant Nautiyal Nautiyal https://spast.org/techrep/article/view/726 Wed, 15 Sep 2021 00:00:00 +0000 SOLAR ENERGY IN NIGERIA -STATUS, UTILITY AND PROCUREMENT https://spast.org/techrep/article/view/1366 <p>Africa is full of natural resources but is lacking to fulfil the energy needs of continent due to lack of technology. Nigeria as it seems is situated in the of Africa. with over 210 million population and 768 km2 area Nigeria is still struggling to fulfil the electricity requirement of the country, as the data shows 46% of overall nation public is still non linked to the grid and most of the electricity generation is being done by non-renewable energy resources which is responsible for pollution in the country. being as a developing nation Nigeria must find out new possibilities to fulfil the electricity requirement and what is a better way than utilising the resource the entire Africa is known for i.e., sun. solar radiation level of Africa is far more than of the other continents. the research paper consists of the study of six zones of Nigeria and its potential to generate green energy in the country.</p> sushil kumar, Kamal Kashyap Copyright (c) 2021 sushil kumar, Kamal Kashyap https://spast.org/techrep/article/view/1366 Wed, 06 Oct 2021 00:00:00 +0000 A Review on Neem oil biodiesel in Compression Ignition engines https://spast.org/techrep/article/view/347 <p>Depletion of fossil fuels urges human world to investigate on alternate fuels derived from edible as well as non-edible oils. Vast research is being carried out for various types of alternate fuels. This paper presents the review of one such fuel namely Neem oil. Usage of edible products in production of biodiesel may lead to food crisis in world market. Hence products which are not commercial and less used by humans were selected for biodiesel production. The review of neem oil mixed with lower viscous oil such as winter green oil was given in terms of its characteristics and performance. Emission characters for various blends of Neem biodiesel were pictorially by comparing with conventional petro diesel.</p> SWATHI BOOSALA, Srikanth Satish Kumar Darapu Copyright (c) 2021 SWATHI BOOSALA, Srikanth Satish Kumar Darapu https://spast.org/techrep/article/view/347 Tue, 14 Sep 2021 00:00:00 +0000 AIRFOIL DESIGN OPTIMIZATION USING MULTI FIDELITY AT LOW REYNOLDS NUMBER FOR FIXED WING UAV https://spast.org/techrep/article/view/1104 <p>A methodology is given to choose an airfoil for a fixed wing UAV, and evaluate based on the mission constraints, and to efficiently optimize the airfoil by using multi-fidelity software such as XFLR5 and ANSYS FLUENT. The analysis solvers are validated for the wind tunnel test data of E387 and CAL2463m airfoil. Then, twenty low speed airfoils for conventional fixed wing UAV are constructed by using the multi-fidelity solvers. The weighting score method is used to select the appropriate airfoil for the given design requirements. The selected airfoil is used as a baseline for the inverse airfoil design optimization step to refine and obtain the optimal airfoil configuration. The effectiveness and feasibility of the proposed method is demonstrated by applying to the design of a conventional wing UAV airfoil.</p> Preety Kumari, ASHOK KUPPUSAMY, Arnob Das Rudra Copyright (c) 2021 Preety Kumari, ASHOK KUPPUSAMY, Arnob Das Rudra https://spast.org/techrep/article/view/1104 Tue, 21 Sep 2021 00:00:00 +0000 DESIGN AND GEOMETRICAL OPTIMIZATION OF NOZZLE TO REDUCE NOISE FOR JET ENGINE https://spast.org/techrep/article/view/1138 <p><em>A scientific payload is used for deep space observations. It consists of several components which are used to observe and detect the objects and its details. Such payloads are used to collect data for tin-filer research and understanding about the universe and to know its hidden mysteries. This research is conducted using several observatory instruments like, X-ray spectroscope, hyper spectral image camera, laser ranging instruments, etc., In this project. a mechanical configuration of X-ray spectroscope is designed considering all the design parameters and constraints. Boeing recently tested a scaled variable area jet nozzle capable of a 20% area change Shape Memory Alloy actuators were used to position 12 interlocking panels at the nozzle exit. A closed loop control system was used to maintain a range of constant diameters with varying flow conditions and to vary the diameter under constant flow conditions. Acoustic data by sideline microphones and flow field measurements at several cross-sections using PIV was collected at each condition. In this paper the variable area nozzle's design is described. The effect of the nozzle's diameter on acoustic performance is presented Flow field data is shown including the effects of the joints between the interlocking panels.</em></p> ASHOK KUPPUSAMY Copyright (c) 2021 ASHOK KUPPUSAMY https://spast.org/techrep/article/view/1138 Wed, 22 Sep 2021 00:00:00 +0000 Investigation on Thermal Analysis of Spacecraft radiators https://spast.org/techrep/article/view/2520 <p>Spacecraft are the vehicle designed to fly in outer space. It mainly consists of 3 major<br>components: the orbiter (the outermost part of spacecraft that enters the orbit), a fuel tank,<br>and two rocket boosters. All spacecraft components have a range of allowable temperatures<br>that must be maintained in order to meet survival and operational (function/performance)<br>requirements during all mission phases. Various temperatures of the spacecraft are<br>regulated through thermal control system which constitutes one of the main systems in a<br>spacecraft. Spacecraft radiators are designed to eject excess heat from spacecraft hardware<br>and also a part of controlling system temperatures as they experience the extreme<br>temperature fluctuations in space. In this research project, the main focus is by comparing<br>between the rectangular and honeycomb structures of space radiators in spacecraft. The<br>thermal analysis on the faces of the spacecraft radiators is analysed on the temperature<br>gradients acting over the radiator panel by applying varying heat loads. From this research<br>output, the honeycomb structures of spacecraft radiator have better results than the<br>rectangular structure of spacecraft radiator in various thermal properties and hence it is great<br>replacement in near future.</p> Venapusa Sravan, HIMANI, DHANRAJ JITENDRA , Senthur Prabu Copyright (c) 2021 Venapusa Sravan, HIMANI, DHANRAJ JITENDRA , Senthur Prabu https://spast.org/techrep/article/view/2520 Sun, 17 Oct 2021 00:00:00 +0000 Optimization of Laser Beam Cutting Machining Parameters using ANOVA and Regression models https://spast.org/techrep/article/view/1962 <p>The Laser Beam Cutting machining (LBM) process is most extensively used for the generation of reliable and complex geometrical shapes on various metals like ferrous, non-ferrous, stones, plastic, and ceramics components. Laser beam cutting gives higher dimensional accuracy and can also be carried out in submerged conditions. The factors or parameters like cutting speed, laser power, gas power, pulse energy, temperature line spacing, scanning speed, etc., will affect the process. Also, the three levels for each factor to be considered to get optimum parameters for the machining process so that we found the percentage of the effect of parameters by considering cutting speed, laser power, and gas power are the factors through using ANOVA and regression in Minitab. And Response optimization is also done by considering the Surface roughness reading for factors. The result of the main effect and optimization plots shows that cutting speed plays a prominent role in finding the surface roughness. The most noteworthy parameters like cutting speed and laser power affecting the surface roughness majorly compared to gas pressure. The optimal parameters and levels are determined using Taguchi methods.</p> Sunil Bellad, Basavaraj G L, Prakash R, Sridevi K Copyright (c) 2021 Sunil Bellad, Basavaraj G L, Prakash R, Sridevi K https://spast.org/techrep/article/view/1962 Fri, 08 Oct 2021 00:00:00 +0000 Design & Experimental Investigation of XY Compliant Mechanism for Precision Applications https://spast.org/techrep/article/view/344 <p>A XY compliant mechanism is designed for the precision application with higher range, precision and accuracy. In earlier work many researchers have used different methods to design compliant mechanism. In this paper XY positioning stage is designed using blocks method. However, the model is monolithic in nature to avoid joints. By using wire EDM the XY model is manufactured. Voice Coil actuators are used for the displacement which give larger range. Analytical modeling is carried out and is validated with MATLAB results. Finally, experimentation is done for performance analysis. The XY model gives ±6mm with motion direction. XY model evaluates both static and dynamic performances.</p> Shrishail Sollapur Copyright (c) 2021 Shrishail Sollapur https://spast.org/techrep/article/view/344 Tue, 14 Sep 2021 00:00:00 +0000 DEVELOPMENT OF AIRFRAME FOR UNMANNED VTOL FLYING PLATFORM https://spast.org/techrep/article/view/1171 <p>A challenging issue associated with fixed-wing Unmanned Aerial Vehicles (UAVs) is that these vehicles are often not appropriate for operating effectively in limited airspace. This problem emerges especially in an urban environment where the usage of a runway is not possible, and UAVs usually have to fly at a relatively low speed and altitude. The development of a vertical take-off and landing (VTOL) fixed-wing plane is a promising trend that hopefully will solve this issue. This project aims to address difficulties relating to reconnaissance and surveillance for military and civilian applications. The design concept simplifies tilt-rotor systems by using only the control fins to shift from horizontal to vertical flight and vice-versa, allowing the motor/rotor elements to be fixed. All the basic maneuvering of the aircraft is handled by the control surfaces of the airframe. The system consists of one wing with two motors and two elevons creating a tractor configuration airframe. The active flow over the surfaces assists in VTOL and allows the aircraft to seamlessly carry out vertical flight such as hovering and offer maneuverability at slow speeds during horizontal flight.</p> Sundar M, ASHOK KUPPUSAMY, Kugharaja V Copyright (c) 2021 Sundar M, ASHOK KUPPUSAMY, Kugharaja V https://spast.org/techrep/article/view/1171 Fri, 24 Sep 2021 00:00:00 +0000 The Design and Development of Advanced Braking System with microcontroller https://spast.org/techrep/article/view/2288 <p>The abrupt evolution of an obstacle while driving is one of the most frequent sources of automobile accidents. Driving responses range from individual to individual in a panic scenario, as does the stopping distance. Some motorists are involved in an accident, while others are not but have experienced severe reactions. A project has been undertaken, which helps reduce the reaction time by supporting the driver to avoid a collision with another vehicle. It is possible to determine the distance between a vehicle or moving vehicle and obstruction using ultrasonic sensor technology. Intelligent mechatronics is used in autonomous braking techniques, which constitute an Ultrasonic wave emitter mounted on the frontal part of an automobile and accomplished of provoking and emitting Ultrasonic waves. An Ultrasonic receiver installed on the frontal part of the vehicle can accept a reflecting Ultrasonic wave signal while the automobile is in motion. A system has been built that allows cars to interact to detect the distance between vehicles, i.e., approaching vehicles from the front or the rear. Additional instructions may be added to assist the driver while on the road. The distance between the obstacle and the vehicle is detected by the reflected wave (detected pulse) that is identified. Then, depending on the detecting pulse information, a microcontroller is appropriated to regulate the vehicle's speed, leading the driver to press the brake pedal and apply tremendous force to the vehicle's brakes for safety reasons.&nbsp; When it comes to enhancing vehicle safety and behavior, the utilization of computers, also known as ECUs (electronic control units), is a powerful stride forward in a particular path. This paper outlines the importance of all the elements of the braking system. The design is made on analytical computations. This paper also illustrates the possible issues and the potentiality for an intelligent braking system in the future.</p> Gurpreet Matharou, Vansh Pradhan, Chirag Gupta, Tushar Ahlawat Copyright (c) 2021 Gurpreet Matharou, Vansh Pradhan, Chirag Gupta, Tushar Ahlawat https://spast.org/techrep/article/view/2288 Thu, 07 Oct 2021 00:00:00 +0000 Comparative study on Thermal Analysis of Disc Brake Using ANSYS simulation https://spast.org/techrep/article/view/2485 <p>The brake system is one of the most important systems of an automobile vehicle. A disc brake is a type of brake that creates friction by forcing stationary pads against a revolving disc using calipers. Pressure is applied to the disc and caliper system mounted to the wheel or axle to slow the vehicle down. The kinetic energy of the vehicle is transformed to thermal energy, which is ultimately discharged into the environment as heat. As a result, some deformations in the disc brakes occur. They are subjected to wear and tear, which might have an impact on their performance. So our main aim is to find a suitable material for disc brakes that can dissipate heat very fast to the environment than others. If it manages to dissipate heat properly it can avoid the distortion which will be produced in the disc which leads to thermal cracking of the disc leading to disc failure. To eliminate such flaws, we need to develop a disc brake material that can endure a specific level of heat and friction while maintaining its efficiency over time. The main goal of this research work is to analyze the thermal stress on the brake disc by ansys simulation and also examine numerous other criteria in order to locate a suitable material for disc brakes. In this work, 3 different disc brake materials namely Al356, cast iron, and SS420 are chosen for thermal analysis by using ansys simulations and the results will be compared among. The simulation findings will help us figure out the temperature, pressure, and heat that can be withstand at its maximum. All of the inputs for the boundary conditions will come from open source data. From this research output, the stainless steels grade SS420 has better results than the Al356, cast iron in various thermal properties and hence it is great replacement in the disc brakes in near future.</p> Vedant Chavan, Guruvasanth A S, Amay Rana , Senthur Prabhu Copyright (c) 2021 Vedant Chavan, Guruvasanth A S https://spast.org/techrep/article/view/2485 Wed, 13 Oct 2021 00:00:00 +0000 Fault Diagnosis of Rolling Element Bearing: A Review https://spast.org/techrep/article/view/513 <p><strong>Abstract</strong></p> <p>The bearing is a highly critical part of every rotating machine which is used to give support to the elements helping in the rotation of the shaft on a fixed structure of the rotating machine. More than 90% of machines are using rolling element bearings and their failure may lead machine failure. According to the research, 90% of the rotatory machines fail due to bearing failure, and 30% of the failure occurs on outer and inner race [1]. Bearing failure may cause severe damage to machines, might endanger the lives of people and may lead to financial losses. The fault diagnosis method will help to diagnose any sudden failure of machines which increases the life of machines and thereby contributing to save the people's life.</p> <p>This article represents a short review on recent trends of the methods used for fault diagnosis in rolling elements bearing. This review article especially emphasises on highlighting the advantages of novel techniques over conventional. Conventionally, the most common methods for detection of fault in rolling elements bearing involves; traditional method (CFD Model, Graph isomorphism network (GIN), Weight horizontal visibility graph, etc.) and Machine learning techniques ( Convolutional neural network (CNN), Artificial Neural Network (ANN), Deep learning diagnosis Techniques, Recurrent Neural Network (RNN) etc.)[2-6]. These methods are used to detect common types of faults viz., fatigue, vibrations, wear, poor lubrication, plastic deformation, incorrect design, corrosion, brinelling, and faulty installation.</p> <p>With recent advancements and advent of industry 4.0 model, industries are transforming the traditional methods to intelligent and digitization techniques, which create high demand for scientific and effective health management of mechanical equipment [5]. Over a last few decades, deep learning techniques are been used to improve the accuracy of fault diagnosis [7].</p> <p>The aim of this paper is to do a comparative study of different fault diagnosis techniques in rolling elements bearing. It will also help to better understand the process and approaches of all types of fault detection techniques, which will give new insights for the research leading to further improvement in the performance of rolling elements bearing. Early and accurate identification of the fault is of paramount importance, as it can help to further prevent the wear and tear of the machine. Identifying suitable technique which can provide high degree of precision and accuracy in early diagnosis will lead to drastic enhancement of the machine performance.</p> <p>This article showcases the method which can detect fault at very high accuracy and improve the life of the bearing under different working conditions and to preserve the rolling machine work in a healthy atmospheric state.</p> <p>&nbsp;</p> <p><strong>Key words</strong>: Rolling Element Bearing, fault diagnosis techniques, convolutional neural network (CNN), deep learning, Bearing, Defect, Recurrent Neural Network (RNN), Graph isomorphism network (GIN), CFD Model, Weight horizontal visibility graph.</p> DEVENDRA SAHU Copyright (c) 2021 DEVENDRA SAHU https://spast.org/techrep/article/view/513 Sun, 19 Sep 2021 00:00:00 +0000 An Investigation of Ti-6Al-4V Brake Disc using Ansys simulation https://spast.org/techrep/article/view/1226 <h2>The objective of this research is to investigate the disc brake performance by comparing two different types of materials like Ti6Al4V (An alloy of Titanium, Aluminium, and Vanadium) and convectional grey cast iron. The comparison of disc brake material is done on the basis of thermal and structural analysis, using Ansys simulation software which will help in the computational dynamics of disk brake in terms of Total heat Flux, Temperature variation, Total deformation and Equivalent (Von Mises Stress). Brake rotors of disc brakes rotate with the wheels, and brake pads, which are fitted to the brake callipers, clamp on these rotors to stop or decelerate the wheels. The brake pads pushing against the rotors generate friction, which transforms kinetic energy into a thermal energy. This thermal energy generates heat, but since the main components are exposed to the atmosphere, this heat can be diffused efficiently. This heat-dissipating property reduces brake fade, which is the phenomenon where braking performance is influenced by the heat that’s why Thermal analysis is being carried out to dissipate the heat efficiently and hence increase the life span of the disk brake. From the simulation results, the change in geometry affects the thermal properties significantly. By performing Topology Optimization in disc brake and by comparing between conventional grey cast iron with Ti-6Al-4V materials in disc brake.</h2> <h2>As mentioned, the whole analysis is run by using Ansys software. By the use of operations such as static structural and Thermal analysis we were able to determine the above mentioned parameters. With the help of thermal analysis, we were able to find out the working and the maximum temperature at which the brake disc may sustain hereby helping vehicles to work properly without the brakes failing even though we continuously drive the vehicle for a long periods of time.</h2> <p>Calculations for the analysis were done from some basic moment and theory concepts from which we could calculate the force which might act on the brake disc and the moment acting on the same brake disc. Updating these values in the ansys software as boundary conditions we were able to acquire required data which tells that Ti6Al4V can withstand</p> <ol> <li>Twice more Deformation than grey cast iron</li> <li>9 times more temperature than grey cast iron</li> <li>10 times more stress than grey cast iron</li> </ol> <p>With all this data we were able to come to a conclusion on the material used for brake disc</p> <p>Also, Titanium alloys have more better features which are</p> <ol> <li>It has high mechanical properties like lightweight, plasticity and strength</li> <li>It has varied design possibilities for development of the product</li> <li>It is a Bio-compatible non-allergic material</li> <li>It has Unique accosting properties</li> </ol> <p>Where the disc brake is crucial part in functioning of the vehicles and from the analysis done it is perfect that Ti-6Al-4V material has better results than grey cast iron in various thermal properties. Hence the Ti-6Al-4v is great replacement of conventional grey cast iron material in the disc brake in near future.</p> Neel Agarwal, Sai Sravan Yarlagadda, Sai Santosh Thatikonda, Senthur Prabu Copyright (c) 2021 Neel Agarwal, Sai Sravan Yarlagadda, Sai Santosh Thatikonda, Senthur Prabu https://spast.org/techrep/article/view/1226 Tue, 28 Sep 2021 00:00:00 +0000 Compatibility of Improvised Archimedes Screw Turbine for Generating Green Energy in the Western Himalayan State of Himachal Pradesh- An experimental study https://spast.org/techrep/article/view/1299 <p>Pollution is now becoming an issue all across the globe. Researchers are struggling to finding out the ways to generate electricity by implementing green energy. Archimedes screw turbine is a traditional technique being implemented from centuries to harness green energy by water. The similar technology is being used now to generate green energy at low head sites. The paper reflects the results that has been attained by changing the number of blades ranges from 1 to 4 at variable flow rate (1 to 4 litres), load (0.5 to 0.9 kg), tilt angle (20 to 25 degree) [1-2] and head (0.56 to 1.25 m). The result analysis reflects the maximum efficiency of over 78% was recorded for a four bladed Archimedes screw turbine runner at flow rate 1 l/s, load 0.9 kg, head 0.56m and at tilt angle 22 degree. The study further reflects the compatibility of such turbines to be installed at small Peniel streams for the western Himalayan state of Himachal Pradesh and can generate over 200 MW of electricity.</p> sushil kumar, Kamal Kashyap Copyright (c) 2021 sushil kumar, Kamal Kashyap https://spast.org/techrep/article/view/1299 Thu, 30 Sep 2021 00:00:00 +0000 Electricity Generation in High-Rise Buildings from Discharged Sewage Water https://spast.org/techrep/article/view/662 <div class="page" title="Page 1"> <div class="layoutArea"> <div class="column"> <p>Nowadays due to rapid urbanization in India and the world, many high-rise buildings have come up for both commercial (office spaces) and residential housing purposes. Plenty of waste, both solid and liquid is generated in such buildings. The modern high-rise complexes have systems to segregate and recycle liquid/solid waste onsite and then use it for watering the plants, in flush tanks, compost preparation etc., whereas in older complexes such systems are absent, and this liquid waste along with the solid waste (from the restrooms) is generally sent to the sewage treatment centres via the city sewer lines. Some studies have been conducted in the design and development of pico-hydro production system for energy generation and storage utilizing the fresh water supplied to residences, with appropriate turbines for the needed head pressure [1-2]. It would be of value if the energy of the liquid wastewater could be harnessed efficiently and power some electrical equipment in the building complex such as lighting the streets, corridors, stairways, parking cellars etc. The motivation behind this study is to bring out the “best out of waste” and use flowing sewagewater [3], a form of renewable energy wisely to generate electricity with maximum efficiency. An innovative electricity generation method from sewage water pipelines is proposed that can recover some of the pumping energy required for pumping water to the overhead tanks. This system draws inspiration from the well-known Hydropower, which is an efficient and cost-competitive renewable energy source that is contributing to more than 16% (4327.8 TWh) of electricity generation worldwide and about 45% of global renewable electricity [4]. Similar to a hydroelectric power station, this system integrates equipment such as wastewater storage tank, turbine and generator. However, as the supply of wastewater is not continuous, the power generated is stored in a battery bank, which is then used for powering various electrical equipment when needed.</p> <p>Wastewater is generated by various activities such as washing, cleaning, water purification etc. The amount of wastewater generated depends on several factors – such as the type of the building (commercial or residential), its occupancy, its height etc. A generalized system design and layout considering several factors, to generate electricity economically with maximum efficiency shall be presented. A separate sewage pipeline network design for collection of liquid wastewater as shown in fig.1 and the design of the liquid waste collection tank is proposed and discussed. This liquid waste collection tank collects all the liquid waste generated from the high-rise buildings (along with the excess rain water available during rainy season) that allows it to flow through the turbine for continuous generation of electricity without any noticeable fluctuations. Techno-economic calculations would be performed [5], the electricity generation potential, the return of investment (ROI) of such a system as shown in fig.2 would be estimated in different scenarios. A methodology for sizing the system viz. the storage tank dimensions, turbine type [6], battery bank specifications etc. shall also be discussed in the paper.</p> <p>The proposed system explores the feasibility of generating electricity from sewage water discharged by high-rise buildings, sustainably, economically, and efficiently. This being a renewable energy source, it not only helps in reduction of greenhouse gas emissions but <br>also indirectly helps in the growth of green industry.<img src="https://spast.org/public/site/images/aditya_15/img-1.png" alt="Sewage pipeline system" width="942" height="1576"></p> </div> </div> </div> Mohan Aditya Pabolu, Mudireddy Raviteja Reddy, Vinod Ram, Kaithepalli Praveen, Ankam Chaitanya Krishna, Venkata N. Nori Copyright (c) 2021 Mohan Aditya Pabolu, Mudireddy Raviteja Reddy, Vinod Ram, Kaithepalli Praveen, Ankam Chaitanya Krishna, Venkata N. Nori https://spast.org/techrep/article/view/662 Thu, 16 Sep 2021 00:00:00 +0000 Digital Twin Technology a New Art of Manufacturing https://spast.org/techrep/article/view/1898 <p>As the industry is stepping into industry 4.0 Digital Twin Technology is been seen as the path for <br>implementation of virtual manufacturing for betterment of industry to produce more efficient and <br>reliable product with minimal modification requirement further as per need of the hour for making <br>product more suitable in market. Being a rapidly growing technology there are many research work <br>going on it at current stage in different form of industry by utilizing multiple domain of Iota, Data <br>acquisition, cloud computing, model and empirical based design process etc. This review article <br>will enlighten on the research work done particularly on Digital Twin Technology previously and <br>identify gaps in the research by Characterizing the technology on state of concept, Terminology <br>and Process associated with it as well as giving a brief idea about how Digital Twin Technology <br>is beneficial to manufacturing.</p> Anand Khandare Copyright (c) 2021 Anand Khandare https://spast.org/techrep/article/view/1898 Fri, 08 Oct 2021 00:00:00 +0000 Rectification of defects occurring in the gate valve manufacturing process by implementing Six Sigma methodology https://spast.org/techrep/article/view/2603 <p>Six Sigma is a methodology containing various tools and techniques for improvement of a process. The purpose of this research is to reduce the defects, maximise the profit and make small scale industries more efficient. This Six Sigma Project was conducted at a valve manufacturing industry located in Maharashtra. While testing of the gate valves, leakage was observed in few valves manufactured in the industry. It was found that the leakage was occurring due to the following defects in the valves – gap between valve and pipe joint, cracks, drill hole misalignment, improper threading, gap between bonnet and body, improper wedge alignment and gasket not fitted properly. After applying Six Sigma tools it was found that if the gap between valve and pipe joint, cracks and drill hole misalignment are rectified then 81.67% defects will be reduced in the industry. Thus, the team decided to overcome these three problems. The above mentioned problems were solved using the analysis and statistical tools of the DMAIC Methodology. The cause-and-effect diagram [1] was used to do the hypothesis. The team had a brainstorming session and listed all the possible reasons that came to mind for the problems. The cause-and-effect diagram has five categories (5M) – Method, Material, Measurement, Machine and Man-power. The hypothesis under Method column contains Inspection - not done properly, SOP not followed and Casting defects. Similarly for Materials column, Raw Material Adulteration and Poor Grade are listed. The Measurement column has observational error, gross error, improper calibration and wrong calculation. While the Machine column contains worn out tool, service not done periodically, improper lubrication, over-run of machines and power cut. The column Manpower contains fatigue, overtime, lack of concentration of workers and their improper training. Now all these hypotheses were used to convert into meaningful solutions using various Six Sigma tools and data provided by the industry. The vision of this work is to make the business more profitable for the industry in the long run. The solutions that will be provided in this research paper can used in other types of valves that are manufactured by this industry. The solutions were implemented and studied for one week during which 50 gate valves were manufactured. The DPMO was 60,000 and the newly achieved Sigma Level was 3.5 but it is predicted that if the solutions are continuously applied for 6 months, then the industry can achieve till Sigma Level 4.0. A control plan was also provided to the industry which will help them to keep implementing the solutions for a longer period of time. The main objectives of this work are as follows – 1. To reduce the occurrence of leaks and cracks in the gate valve while manufacturing. 2. To improve the process and reduce the process time. 3. To estimate and reduce the cost of poor quality. The defective products in the testing phase are usually re-machined and re-assembled if possible or else they are turned into scrap. To do these re-machining and re-assembly, energy wastage takes place. Again, to melt the scrap for new casts energy wastage occurs. Whereas, if the defects can be prevented in the first place, then a lot of energy will be saved in the long run which will be a huge benefit for the environment. The industry was previously operating at 3 Sigma Level. After implementing the DMAIC methodology the Sigma Level increased to 3.5.</p> Susobhan Biswas, Dr. Vijayaragavan E., Faizan Danish Nachan, Sohail Ahamed Copyright (c) 2021 Susobhan Biswas, Dr. Vijayaragavan E., Faizan Danish Nachan, Sohail Ahamed https://spast.org/techrep/article/view/2603 Sun, 17 Oct 2021 00:00:00 +0000 Investigations of Turbulence in the IIAEM Wind-tunnel using Computational Fluid Dynamics https://spast.org/techrep/article/view/530 <p>In aeronautical engineering, the use wind tunnel occupies an important role in driving research for the development of green, sustainable technologies. For instance, the design of powered, low carbon emitting sailplane called the Jain sailplane is one of the recent developments witnessed in this direction. We at IIAEM are concerned with designing an open-circuit, low-speed wind tunnel that is devoid of turbulence. The aim is to modify the existing 0.6m x 0.6m wind tunnel and provide a platform for testing green, environmentally friendly aerospace components in the future. Several methods like active and passive flow control techniques are available that alter the fluid flow and produces a turbulence free test section. In order to solve this problem of turbulence, as a first step, Computational Fluid Dynamics (CFD) simulations are performed to identify sources of turbulence. A review of literature showed that previous studies have used CFD to study the flow quality inside different closed or open-loop wind tunnels at different sections but not that of test section [1-5]. The study of turbulence existing inside the test section using CFD have not been previously attempted according to the authors’ knowledge. The simulations in this research are conducted in the commercial CFD code ANSYS Fluent. As part of the modelling process, geometrical data available from manufacturer is obtained from existing literature and transferred to ANSYS <em>DesignModeler</em>. An inlet velocity of 2 m/s is assumed. In order to verify the CFD simulations, grids of uniformly increasing mesh resolutions are designed using the <em>Mesh tool</em> available in ANSYS to perform grid independence study. In the next step, four turbulence models namely Spalart-Allamaras, standard k-ω, Shear Stress Transport (SST) k-ω and realizable k-ε are used to perform a detailed analysis of turbulence intensity and vorticity in the contraction, test section and diffuser sections of the wind tunnel. Furthermore, detailed investigations on turbulence intensity are carried out at the centre of test section (Location 1), 0.1 m (Location 2), 0.2 m (Location 3) and 0.25 m (Location 4) radially from the centre. The empirically designed eddy-viscosity turbulence models - standard k-ω, Shear Stress Transport (SST) k-ω and realizable k-ε predicted varied profiles of turbulence intensity in the various locations (S-A model, not included). At the centre (Location 1), the standard k-ω and SST k-ω showed that the turbulence intensity increases linearly in the axial direction. The realizable k-ε showed that the turbulence intensity increases for certain distance and then decreases. For Location 2, all turbulence models predicted linearly increasing turbulence intensities. For Location 3, the standard k-ω and realizable k-ε predicted linear increment while SST k-ω provided a non-linear variation. At Location 4, the three turbulence models predicted non-linear variation in the turbulence intensity. Besides analysing the test sections, the turbulence models are used to study the whole tunnel sections. The results are shown in Fig.1. The validation of the CFD results is performed by comparing with analytical formula for velocity at test section inlet. The results showed that the CFD results compare reasonably well within error limits. The obtained results form the first step in the development of sustainable, green technologies and aerospace components in the foreseeable future.</p> Samuel Luis, Pooja More, Sridutta Satuluri, Dr. Aravind Seeni Copyright (c) 2021 Samuel Luis, Pooja More, Sridutta Satuluri, Dr. Aravind Seeni https://spast.org/techrep/article/view/530 Thu, 16 Sep 2021 00:00:00 +0000 Conceptual Design of Jain University Sailplane based on Concurrent Engineering within Aerospace Engineering Curriculum https://spast.org/techrep/article/view/740 <p>There is ever growing interest in the design of high-performance sailplanes since the start of</p> <p>the last century [1-3]. Sailplanes or gliders form an example of sustainable engineering in aeronautics as there is practically little to no carbon footprint. The students of aerospace engineering at IIAEM, Jain University are designing a sailplane that can reach a maximum altitude of 7000 feet. The maximum weight of sailplane is 500 Kg. This paper reports ongoing progress made within the sailplane project management. Concurrent Engineering (CE) as a design methodology is adopted and implemented for the conceptual design phase of this project. CE involves simultaneous sharing of data within various teams thereby increasing productivity and reducing time for product design. According to the author’s knowledge, there have been no prior reports on the application of CE in aircraft design within educational curriculum and this is the first known instance of applying the principles of CE in sailplane design. Six main groups and eight sub-groups as shown in Fig.1. are formed based on Raymer’s Conceptual Design Methodology [4]. The total team composition consists of 102 student members and a professor, specialist in aerodynamics. Every group and sub-group is allocated with a group leader. These group leaders collectively fall under the supervision of the Professor and a student project manager.</p> <p>As the project involves extensive data sharing and periodic design iterations, it was imperative that interrelationships between the different groups are handled properly through the implementation of flowcharts even before the start of the project. Fishbone Diagram has been applied for the project by categorizing the different tasks throughout the design procedure. The design requirements and deliverables from each group and sub-group are initially laid out. As the tasks get completed, team meetings are conducted for project updates. The advancements by each group are regularly put forward and the next plan of action discussed. Knowledge sharing within groups are enabled through online demo of software tools. For instance, the design of airfoils and wings can be performed through a variety software codes available. Based on careful planning, trade-offs on software tools for specific applications are performed by the Professor and the students prepare for sharing the expertise on those specific tools to the whole team through an online session. This allows knowledge sharing and drives innovation during the design process. An online repository is maintained to share important literature on sailplane design and software. So far, the ADS sub-group, AGG main group and WES sub-group have completed the design of airfoil and wing for the sailplane. So far, the team has been successful in generation of ideas and implementing in a project-based learning method efficiently. The interactions between the groups are investigated and a flowchart based on CE principles is drawn. This is provided in illustrated form in Fig.2. Efficient methods of sailplane design based on CE methodology within an education curriculum have been applied. So far, the method has yielded successful results. The results of this work be presented in this paper.</p> Sridutta Satuluri , Dr. Aravind Seeni Copyright (c) 2021 Sridutta Satuluri , Dr. Aravind Seeni https://spast.org/techrep/article/view/740 Wed, 15 Sep 2021 00:00:00 +0000 CFD Simulation and Parametric Optimization of Y-type Hydrogen Carburettor https://spast.org/techrep/article/view/437 <p>Energy demand is increasing rapidly due to population growth day by day. The finite potential of petrol and diesel was made to look for an alternative fuels. The usage of hydrogen internal combustion engines reduces the consumption of non-renewable energy resources and exhaust emissions [1]. Hydrogen plays a vital role in clean energy sector and it paves a way for better sustainability in different areas [2]. Many studies were carried out related to the engine performance, fuel economy and exhaust emissions by using hydrogen as an alternative fuel. Usage of hydrogen in hybrid vehicles yields positive results; more studies were carried out for alternative fuels for hybrid vehicles [3]. Further studies were carried out to determine the effect of hydrogen on exhaust emissions [4,5]. It was found that the usage of hydrogen reduces exhaust emissions and increases the thermal efficiency of engine [6]. Some of the studies were carried out to look at the negative impact of using hydrogen on engine performance [7].</p> <p>In computational study, several researchers performed CFD analysis to determine flow characteristics of air and fuel mixture in carburettors. A flow characteristic study was carried for producer gas and air mixture in a carburettor which is specially designed for producer gas [8,9]. Further, a CFD analysis was performed to determine the flow characteristics of air &amp; fuel mixture for a carburettor design with different valve positions [10]. With this literature review, extensive research work can be carried out with the present Gaseous Fuel Carburettor’s and further much more development and modifications can be done for the commercial utilization of alternative gaseous fuels as a major fuel for I.C. Engines and thereby reducing the load on the conventional fossil fuels i.e. Gasoline and Diesel. These type of parametric optimization studies shall pave a way in overcoming multiple hardware building and testing and might allow to get enhanced performance of the prototyping model that could lead to blend suitably for the engine applications specified. These aspects of literature were considered to provide a design alternative in bridging the technology gap in the area of low energy fuel based engine applications for the coming years. This paper aims at optimizing the uniformity in air-fuel mixture &amp; equivalence ratio in Y-type carburettor for hydrogen fuel by varying angle between air &amp; fuel inlet along with length of outlet.</p> <p>The current CFD study aims to provide insight into various parameters to be considered in order to achieve a balanced air-fuel ratio. In this study, a simple Y-pipe carburettor design is studied with the varying angle between air and fuel pipe and the length of the exit tube to achieve a better air-fuel ratio and uniformity. This CFD study was performed using Altair Hypermesh and ANSYS FLUENT packages. From the CFD results, it was concluded that uniformity in fuel mixture varies with the angle between air, fuel inlet &amp; length of mixture outlet. The uniformity index varies from 0.6 to 0.8 for different geometries whereas the equivalence ratio varies from 0.5 to 0.8. Although 90-degree geometry with 100mm extrusion at outlet yields better uniformity in the fuel mixture, it falls behind the 90-degree geometry in equivalence ratio. Geometry with a 90-degree inlet angle showed better results with 0.82 &amp; 0.72 for equivalence ratio and uniformity index respectively.</p> Bharatish A Copyright (c) 2021 Bharatish A https://spast.org/techrep/article/view/437 Wed, 15 Sep 2021 00:00:00 +0000 Comparative analysis of Measurement Uncertainty in cubic concrete Compression testing https://spast.org/techrep/article/view/1526 <p>Concrete blocks are one of the important and vital engineering material in the field of construction. To enhance the quality of the block testing is an essential process. There are several tastings are available, in this paper the uniaxial compression testing is done for the sample concrete blocks. For the testing concrete cubic specimen with the phase length of 100 mm is taken. The testing is done physically and the compression strength is studied extensively with the theoretical values. And further the uncertainty measurement analysis done to the test of uniaxial compression test. The achieved uncertainty values are subjected to comparison of existed values of measurement uncertainty.&nbsp;</p> <p>&nbsp;</p> shankar Amalaraj Copyright (c) 2021 shankar Amalaraj https://spast.org/techrep/article/view/1526 Thu, 07 Oct 2021 00:00:00 +0000 Numerical Investigation of Boiling Flow in Oval Tube with Different Ellipticity https://spast.org/techrep/article/view/1223 <p>The enhancement of the heat transfer is crucial in handling heat energy released from equipment, which is having increasing demand as more energy is utilized to ease our daily livings. With that stated, oval tube is having considerable attention in thermofluidic application because of less pressure drop while having higher heat transfer coefficient compared to conventional circular pipe [1]. This is because elliptical cross sectional tube has higher surface to cross sectional flow area ratio [2], which also beneficial for the compact design of heat exchanger. Moreover, the heat transfer and pressure drop at the exterior of the pipe is also having potential to be improved [3]. The oval tube is being used in many fields related to energy conversion and transfer, such as heat exchangers, air-conditioning, refrigeration and heat pump, solar collector, automotive radiators, cooling of electronic equipment fuel cell engine and so on. Recently boiling heat transfer has gained traction as an enhancement method over the single phase flow in pipe as it offer higher heat transfer performance. This is attributed to the heat required to change the liquid phase to gas phase in the heat transfer fluid, on top of the conventional single phase heat up process [4]. In boiling process, pipe orientation is dictating factor. Horizontal boiling is found having huge difference compared to vertical orientation because of the buoyancy effect that come from gravity [5]. The vapor phase which has very low density will stay at the upper part of the tube. In addition, the higher temperature particles will tend to move to the upper side of the tube, while the pressure at the upper side will be slightly lower which may affect the nucleation of bubbles when the heat flux of the tube is constant. These phenomena cause the horizontal boiling flow to become not axisymmetric.</p> <p>Through literature review, it is found that most of the researches done for boiling are mainly being conducted experimentally, while for numerical study, the research on elliptical cross-sectional pipe in boiling flow is very limited. One of the possible reasons is that the non-axisymmetric of the horizontal flow increases the complexity in solving the numerical equations when it is studied through computational research. On the contrary, experimental research can be dangerous when handling high heat flux and the vaporization of the liquid. Furthermore, the cost for setting up an experiment is relatively high compared to numerical simulations especially when there is need to vary the pipe geometry in order to get comprehensive overview. Numerical study stands to be a better choice in handling various variables as the geometrical models can be alter easily and the boundary conditions can be setup accurately, hence giving results with better insight, which is difficult to obtain through experiments. Thus, it is of interest to study the effect of different ellipticity of horizontal oval tube towards the heat transfer performance.</p> <p>In this research, the enhancement of the heat transfer performance resulting from boiling flow in horizontal oval tube will be conducted numerically. The performance is accounted from overall heat transfer and pressure drop. A three-dimensional computational model will be generated to cater the tubes with different ellipticity. The example of geometry with ellipticity of 0.5 is shown in fig. 1. With the model governed by the conservation of mass, momentum, and energy equations, the RPI wall boiling model will be adopted to capture the heat transfer at the wall with the assumption that the maximum temperature difference for the vapor phase is lower than 10 K. Renormalization Group (RNG) k-epsilon turbulence model will be applied to handle the turbulence within the pipe. The operating pressure, mass flux, heat flux, length of the tube and cross section perimeter will be maintained constant to create a fair comparison on different ellipticity.</p> <p>At the end of the numerical research, it is expected to find out the optimal ellipticity for the best heat transfer performance, as more heat transfer always accompany with higher pressure drop. It is predicted that ellipticity at 0.5 will provide best heat transfer performance with the consideration of high heat transfer and acceptable pressure drop. The research findings will give insight on numerical study of horizontal boiling heat transfer and provide clearer view in utilizing oval tube in heat exchanger.</p> Kim Leong Liaw, Dr. Jundika Kurnia Copyright (c) 2021 Kim Leong Liaw, Dr. Jundika Kurnia https://spast.org/techrep/article/view/1223 Tue, 28 Sep 2021 00:00:00 +0000 Evaluation of different slip mechanisms in relation to various nanofluid consideration factors https://spast.org/techrep/article/view/869 <p>The improved heat transfer capabilities of nanofluids have enticed researchers to use these fluids in a variety of applications. Nanofluids are engineered colloids consisting of a base fluid with nanoparticles ranging in size from 1 to 100 nm that have enhanced thermophysical characteristics over base fluid. Many studies have been done in the subject of nanofluids, mainly focusing on their thermophysical characteristics and applications in thermal engineering domains. There is relatively little known about the behaviour of nanoparticles in base fluids. How various forces (slip mechanism) act on nanoparticles and how this may affect heat transport characteristics. According to researchers [1], the major explanation for the increased thermal characteristics is related to the Brownian motion of the suspended nanoparticles (Eqn 1). But, in doing so, are we ignoring the effect of other slip mechanisms? Will they not affect the thermal properties and flow behaviour of nanofluids? These are the questions that we have attempted to answer in this study.</p> <p>The main objective of this study is to do scaling analysis on nanofluids while taking into account many factors such as the shape and type of nanoparticles in nanofluids (Fig .1), the kind of base fluid, and the concentration of nanoparticles in nanofluids flowing through a microchannel (Fig. 2). A circular microchannel with uniform heat flux is used for the study. In flow heat transfer, the resulting velocity of nanoparticles is given by different forces ((drag force, rotational force, gravity force, thermophoresis force Brownian force, Saffman’s lift force, Magnus force)) acting on the nanofluids and is represented in Eqn. 2 which is iteratively solved in MATLAB. The numerical analysis is carried out using a combined Euler and Lagrange technique. In this analysis, the relative speed between the base fluid and the particle was revealed to be very small (10<sup>-13</sup>-10<sup>-18</sup>), but this value significantly affect the different slip mechanisms mainly the generated Drag force.</p> <p>In this paper, this technique is utilised to model the flow and migration of nanoparticles in a single channel. These values are used to examine the impact of various forces (Eqn 3) on the heat transfer enhancement process. Based on these findings, we may deduce the two-phase flow nature of nanoparticle suspensions and their implications for nanofluid convective heat transfer [2-3].</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; (2)</p> <p>&nbsp;</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; (3)</p> <p>Based on this scaling study, it is discovered that all of the slip mechanisms used are more dominant for cylindrical particles than for other shape particles such as spherical and sheet particles. The final results of all of this analysis are deemed optimum conditional parameters for analysing thermal fluid performance for various types of microchannels in future investigations.</p> <p>&nbsp;</p> <p><strong>Fig.1.</strong> Nanofluids parameters in contributed velocity results.</p> <p>&nbsp;</p> <p><strong>Fig.2.</strong> Circular microchannel.</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> Devansh Srivastava, Dhanshyam Raj, Manish Kumar, Abhishek Kumar, Devendra Yadav Copyright (c) 2021 Devansh Srivastava, Dhanshyam Raj, Manish Kumar, Abhishek Kumar, Devendra Yadav https://spast.org/techrep/article/view/869 Thu, 16 Sep 2021 00:00:00 +0000 Numerical simulation on drawing process parameters optimization for better quality of formed cups by using Taguchi based ELimination and Choice Expressing REality Ranking Approach https://spast.org/techrep/article/view/1011 <p>Drawing problems are inherently complex because they involve shape, size, boundary, and material properties. The drawing part contains many parameters, such as draw force, draw radius, punch velocity and its trajectories etc. Therefore, designing a local drawing tool involves trial and error. In order to reduce expensive experimental error steps, the finite element method can be used to simulate the process. This research is related to the development of cost-effective components, short lead times in the design, development, testing, and testing phases, and large amounts of regular production and supply. In this work, the importance of the three important parameters of the deep drawing process is velocity (5, 10, 15 mm/s), Co efficient of friction (0.15, 0.2, 0.2) and punch radius (1.5t, 2t, 2.5t). The drawing scale (1.5, 2, and 2.5) on the drawing properties. Differences in thickness and spring back of formed parts may cause stress concentration and accelerate damage. Taguchi experimental design and analysis of variance are used to analyze the process parameters that affect the depth drawing of the cylindrical cup assembly. Using finite element analysis, the orthogonal Taguchi matrix L9 is used to simulate the parameters of deep drawing. Then get the best path from Taguchi's experimental design. Virtualization is performed on the Inspire Form FEA software and CRCA material for deep drawing.</p> Sundar Sivam Copyright (c) 2021 Sundar Sivam https://spast.org/techrep/article/view/1011 Mon, 20 Sep 2021 00:00:00 +0000 Static and Total Pressure Analysis of Three-Way Catalytic Convertor using CFD https://spast.org/techrep/article/view/1841 <p>Air pollution from automobiles both commercial and passenger vehicles push the research to make changes in catalytic convertor. Most of the commercial vehicles like coal transport and mineral transport trucks relay on diesel fuel.&nbsp; Hence, we consider the emission of carbon monoxide, unburned hydrocarbons and nitrogen oxides. The incomplete combustion of fuels causes the emission of partial oxidation products such as alcohols, aldehydes. The whole process of this project is done with the help of CFD approach because it will reduce the material waste and we can optimize according to our desired results. In this research work, a numerical analysis has been carried out on the catalytic converter by varying the coating materials. Magnesium Oxide (MgO) and Platinum with Palladium was selected as coating materials. For comparison purpose, normal catalytic converter without coating was analyzed using CFD software. Different output characteristics of the exhaust gases’ static pressure and total pressure in the catalytic convertor are compared with each other. Outcomes of the numerical analysis shows that the catalytic converter which is coated with Platinum and Palladium particles yields the better static and total pressure than that of normal and magnesium oxide (MgO) particles coated catalytic converter.</p> Mayakannan Selvaraju, Girimurugan R, Logesh Kumar M A, Manikandan B; Shilaja.C Copyright (c) 2021 Mayakannan Selvaraju, Girimurugan R, Logesh Kumar M A, Manikandan B; Shilaja.C https://spast.org/techrep/article/view/1841 Fri, 08 Oct 2021 00:00:00 +0000 Design optimization of H-CSTR reactor to minimize Stagnation Zone for Bio-hydrogen production https://spast.org/techrep/article/view/832 <p>Energy is a vital part of human society which enables better and prosperous future, yet dependency on fossil fuels results in climate change, environmental degradation and health issues [1]. Hydrogen holds great potential to be a clean and renewable form of energy. There are lots of ways by which hydrogen can be produced such as electrolysis of water, thermo-catalytic reformation of hydrogen-rich organic compounds, and biological processes [2](Younesi et al., 2008). Here, we are focusing on hydrogen production using biological process.</p> <p>The anaerobic fermentation is one of the promising biological processes by which hydrogen can be produced from carbohydrate rich raw materials such as wastewater, food waste and agricultural waste [3](Ri et al., 2017). Research has been conducted on various kinds of reactor system for hydrogen production using anaerobic fermentation and the continuous reactor system is the one which is most widely used reactor system [3](Ri et al., 2017).</p> <p>&nbsp;</p> <p>There has been little work done on the horizontal continuous stirred-tank reactor [4](Brindhadevi et al., 2021). This research focuses to optimize the design of a lab-scale horizontal continuous stirred-tank reactor (HCSTR) in order to make the effective working volume relatively large as compared to scale Vertical continuous stirred-tank reactor (VCSTR).&nbsp;</p> <p>Using Computational Fluid Dynamics (CFD) simulation with a multi-phase 2D and 3D flow process, we will determine the minimum agitating speed range to minimize stagnation zone by analysing the generated flow pattern.</p> <p>&nbsp;</p> <p>The main objective of this paper is to minimize the stagnation zone in the proposed design at a minimum possible agitation speed as compared to the existing reactor under the same condition and with a more effective working volume.&nbsp;</p> <p>Our other objective includes optimisation of the impeller design, so as to achieve the said result. We are planning to optimise the impeller design with the help of parametric analysis in ANSYS workbench using RSM – Response surface modelling.</p> <p>The outcome of this study is expected to provide an optimised design of a H-CSTR for Bio-hydrogen production.</p> <p>Initial simulations were done for proving the proof of concept as well as the viability of the model using a 2D multi-phase fluid flow analysis using the MRF (Multiple reference frame method) to simulate the rotation of the impeller. The simulations were done with an impeller rotation rate of 30 rpm and 70 rpm.</p> Deerajkumar Parthipan, Sagar, Sagar Copyright (c) 2021 Deerajkumar Parthipan, Sagar, Sagar https://spast.org/techrep/article/view/832 Sat, 09 Oct 2021 00:00:00 +0000 The Multi Body Dynamic Analysis of An All-Terrain Vehicle. https://spast.org/techrep/article/view/638 <p>When the roads vanish, the suspension system comes into the picture majorly. Designing an ATV suitable for most off-road conditions is still a target for most existing companies. Most off-road terrains are difficult to maneuver, causing high reaction forces onto the driver. A considerably less off-road terrain causes an ATV to roll as the vehicle is not designed for that purpose. An ATV, or rather a customizable ride quality ATV is what we intend to design by the end of the project. The main objective of this work is to cause minimum roll, reduce steering effort, allow end-user customizability, and thereby provide better stability. Hence the outcome of this work is to increase roll camber gain, reduce scrub and weight, minimize toe on the front, and keep the roll center dynamically as close as possible to the center of gravity. This work aims to design and analyze the suspension geometry of an ATV, both at the front end and the rear end, using the Multi-body dynamics method on LOTUS Shark Suspension Analysis software. The main outcomes of this work are to cause minimum roll, reduce steering effort, allow end-user customizability, and thereby provide better stability. Hence the outcome of this work is to increase roll camber gain, reduce scrub and weight, minimize toe on the front, and keep the roll center dynamically as close as possible to the center of gravity. When the roads vanish, the suspension system comes into the picture majorly. Designing an ATV suitable for most off-road conditions is still a target for most existing companies. Most off-road terrains are difficult to maneuver, causing high reaction forces onto the driver. A considerably less off-road terrain causes an ATV to roll as the vehicle is not designed for that purpose. An ATV, or rather a customizable ride quality ATV is what we intend to design by the end of the project. The front suspension geometry is chosen to be independent Double Wishbone type, and the Rear wishbone is chosen to be H Arm type double-wishbone with no Control link and thereby zero toes. The main objective of this work is to cause minimum roll, reduce steering effort and thereby provide better stability. Hence the objectives of this work remain to increase roll camber gain, reduce scrub and weight, minimize toe on the front, and keep the roll center dynamically as close as possible to the center of gravity. The hardpoints are thereby chosen to meet these objectives by successive iterations on LOTUS Shark Suspension Analysis. The design and analysis of the individual components and the complete vehicle will be carried out on SOLIDWORKS and Ansys. Each component of the suspension geometry is taken under analysis for fatigue and different load operations. The subsequent materials and their properties are iterated accordingly concerning the safety factor, thereby obtained and their utility. The damping and the spring calculations are done to the vehicle roll rate, ride rate, natural frequencies, load distributions, wheel and spring travel- motion ratio, springs progression, and other characteristics.</p> Srikar Dhulipalla Copyright (c) 2021 Srikar Dhulipalla https://spast.org/techrep/article/view/638 Thu, 16 Sep 2021 00:00:00 +0000 A Numerical Process parameter optimization of Multi stage deep drawing based on hybrid models RSM-FEM- RBNN-CSO and Validation by experimental https://spast.org/techrep/article/view/394 <p>This study proposes a full and efficient optimization approach, starting with modelling by RSM (Response Surface Methodology) and concluding with optimal process parameter identification. Based on this, an optimal neural network was developed to improve cylindrical cup deep drawing. Three characteristics are used to fabricate the cups: clearance, punch radius, and coefficient of friction. This parameter demonstrates the resultant tool force, spring back, maximum forming limiting curve and maximum thinning rate of cylinder cups. Initially, the three inputs are varied to measure the outcome by simulation software by Altair inspire form. Then, using the quadratic based linear model fitting, the equations for each output are designed. The generated objective function is then used to establish the ideal process parameters for the cylindrical cups. The proposed method is compared to real-time physical experiments.</p> Sundar Sivam Copyright (c) 2021 Sundar Sivam https://spast.org/techrep/article/view/394 Thu, 16 Sep 2021 00:00:00 +0000 A Study on Performance Evaluation of solar PV air conditioning System Using Simulatio https://spast.org/techrep/article/view/2693 <p>Now a day, the demand for air conditioning is increasing rapidly in almost around the world, <br>especially in tropical climates. This in turn is responsible for the rapid increase in air <br>conditioning. In subtropical cities, air conditioning is a standard requirement for building. Air <br>conditioners and refrigerators are the only devices that consume the most electricity, upto 70% <br>of household items. This results in a rapid increase in demand for electricity on summer days, <br>causing increase in the use of fossil fuels and nuclear power, primarily responsible for global <br>warming and pollution of the air. In this research work, an attempt has been made between the <br>conventional air conditioning and a solar PV air conditioning system. The CAD model of the air <br>conditioning system is made by using the solid works software. A comparative study has been <br>made on the performance evaluation of the conventional and a solar PV air conditioning system<br>with the help of Ansys workbench by considering the thermal analysis in terms of a quantitative <br>analysis and qualitative estimation of a single room equipped with air conditioning. From this <br>research output, the solar PV air conditioning system shows the better results in various <br>thermal properties on different working conditions and thereby the electricity consumption is <br>reduce by introducing solar thermal energy.</p> Mohammed Rayyan Khan, Digvijay Singh Choudhary, Senthur Prabu Copyright (c) 2021 Mohammed Rayyan Khan, Digvijay Singh Choudhary, Senthur Prabu https://spast.org/techrep/article/view/2693 Thu, 21 Oct 2021 00:00:00 +0000 Design And Fabrication Of Industrial Robotic Trolley with Automatic Control System https://spast.org/techrep/article/view/2297 <p>A<strong>bstract: </strong>-&nbsp; Scrap metal consists of recyclable materials that remain from the production and consumption of materials such as automotive parts, building materials and unused materials. Unlike waste, scrap metal has economic value, especially recovered metals, and non-metallic materials are often recovered for recycling. The goal of the project is to develop scrap metal collection robots. Because it's not a good way to achieve full automation, you can create something that's powered by a remote control, which may or may not be wireless. With four wheels and one hand, The robot&nbsp; can collect waste. He can utilise his feet to conquer little barriers. Although the project may sometimes appear simple, it takes a lot of work to create a working model. It is currently equipped with a manual and time consuming scrap collector. The cost will be exorbitant and you will find it very difficult to buy when you go into automated production. The project offers a completely different sample and operates on machine components, which are significantly cheaper than other entire scrap collectors. The project is a complete project. One of the attractions of this scrap collector is that it runs on solar energy. It is a renewable energy source.</p> silkson John Copyright (c) 2021 silkson John https://spast.org/techrep/article/view/2297 Thu, 07 Oct 2021 00:00:00 +0000 Investigation on Performance Evaluation, Thermal and Structural Analysis of Steam Turbine Blades https://spast.org/techrep/article/view/2730 <h2>The main objective of this research paper is to investigate the thermal efficiency of the steam turbine blades made up of Inconel 718 compare to the conventional stainless steel 12cr grade. Alongside, the effect of differential expansion of the turbine blades due to temperature gradient inside the steam turbine is also carried out to prevent damage. Turbine blades are subjected to extreme temperature circumstances inside a steam turbine during operation. They come across extremely high stresses as well as potentially higher vibration. These can lead to blade failures, potentially deteriorate the turbine, therefore turbine blades must be designed to resist these conditions. Inconel alloys are well known as oxidation and corrosion resistant materials at elevated temperatures and are well suited for extreme in-service environments where it is subjected to high mechanical loads. Inconel's high-temperature strength is developed by solid solution strengthening or precipitation hardening, depending on the alloy. Inconel retains strength over a wide temperature range, attractive for high-temperature applications where aluminium and steel would succumb to creep as a result of thermally induced crystal vacancies. In the present research work, the CAD model of the steam turbine blades is made by using the solid works software. A study has been made on the performance evaluation of the steam turbine blades and also with the help of Ansys workbench, the thermal and static structural analysis is carried out by considering the both heat boundary conditions to optimize for better functioning of the steam turbine blades in extreme temperature conditions. From this research output, the steam turbine blades show the better results in various thermal properties on different working temperatures. Hence it is great replacement of conventional stainless steel 12cr grade with Inconel 718 in the steam turbine blades. Therefore the results will support better for the steam turbine blades manufacturer in near future.</h2> Arkadeep Mukherjee, Naman, Parth, Varun, Senthur Copyright (c) 2021 Arkadeep Mukherjee, Naman, Parth, Varun, Senthur https://spast.org/techrep/article/view/2730 Thu, 21 Oct 2021 00:00:00 +0000 Effects of nitro-paraffin based fuel additive on performance and emission characteristics of motorcycle gasoline engines https://spast.org/techrep/article/view/1005 <p>In Vietnam, following the socio-economic development, the number of transport means equipped with internal combustion engine increases very fast, in which the number of in-use motorcycles has reached to about 60 units by the end of 2020. This has caused the growing concern on fuel depletion and environmental air pollution from toxic exhaust gas. Therefore, researches on effective use of fuel in engine and emissions reduction are significantly important.</p> <p>Many technological solutions have been studied&nbsp;to lessen engine tailpipe emissions and reduce fossil fuel consumption, including the improvement of petroleum originated fuel quality, installation of three way catalytic converters (TWCs) on cars [1] and using alternative fuel,&nbsp;such as biodiesels, methanol and ethanol [2-4]. The studies on using alternative fuels showed that emissions of CO, HC and smock decreased significantly but NO<sub>x</sub> and fuel consumption tended to increase. Other drawbacks were high production cost, limited amount, required engine modification for using high ratio of alternative fuel in blending with the fossil fuels.</p> <p>For motorcycles, TWCs are normally not installed because they will increase the price of these transport means; furthermore, TWCs will operate inefficiently when transient driving (stop and go) occurs more often due to congested traffic conditions in crowded developing cities. &nbsp;As a result, using fuel additives is of interest of many researchers for improvement of fuel combustion to reduce fuel consumption and exhaust emissions [5-10]. The most commonly used additives for gasoline fuel are oxygenates such as methanol, ethanol, methyl tertiary butyl ether (MTBE), acetone [8-10], which increase oxygen concentration and octane rating of the blended fuel. However, these substances have some drawbacks. They need to be blended with the fuel at high dosage and hence dilutes the energy content of the fuel blend and do not perform substantially better than straight-run gasoline and increase the cost of the fuel. &nbsp;</p> <p>This paper studies the use of the nitro-paraffin based fuel additive for gasoline-ethanol fuel blend. The additive substance is referred as Maz-Nitro, supplied by Maz Energy Pte Ltd. The additive employs a unique combination of nitroparaffins (NO<sub>2</sub> integrated with paraffin C1-C3) and ester oil. The objective of the study is to investigate effects of this additive on engine performance and emissions characteristics.</p> <p>The study was conducted experimentally on a Super Dream motorcycle on the chassis-dyno in the Laboratory &nbsp;and on some popular motorcycles in the road test. The fuel used in this study is the popular commercial bio-gasoline E5 in Vietnam, which is a blend of 95% gasoline RON-92 and 5% ethanol. The additive blend consists of CH<sub>3</sub>NO<sub>2</sub> = 18.18%; C<sub>2</sub>H<sub>5</sub>NO<sub>2</sub> = 18.18%; C<sub>3</sub>H<sub>7</sub>NO<sub>2</sub> = 52.73%, C<sub>7</sub>H<sub>8</sub> = 9.09%; Ester = 1.82% by volume. For laboratory test, the additive was blended with the fuel at dosage of 0, &nbsp;500 ppm, 750 ppm and 1000 ppm. The road tests was conducted with additive dosage that give best engine performance and emissions compared with other dosage.</p> <p>Laboratory test results with different Maz dosage at full load are indicated in figures 1 to figure 5.&nbsp; The results showed that the additive dosage of &nbsp;750 ppm gives a good improvement of engine operation in fuel saving and emissions reduction. The fuel saving and power increase are up to 4%,&nbsp; reductions of&nbsp; CO, HC, and NOx emissions are up to 10.3 %, 16 %, and 12 % respectively.</p> <p>Road tests were conducted with additive dosage of 750ppm to evaluate the effect of Maz additive on fuel consumption of the test motorbikes under the real running conditions. The motorbikes are run under real conditions without any constraint with speed. The measured fuel consumption here reflects the average data collected in each 100 km of voyage. Results showed that treating the fuel with Maz nitro can save the fuel consumption from 2.8% to 8.9%.</p> <table> <tbody> <tr> <td width="0">&nbsp;</td> <td width="260">&nbsp;</td> <td width="317">&nbsp;</td> <td width="248">&nbsp;</td> </tr> <tr> <td>&nbsp;</td> <td rowspan="2">&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> </tr> <tr> <td>&nbsp;</td> </tr> </tbody> </table> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>In brief, the nitroparaffin based fuel additive can save fuel and reduce exhaust emissions significantly. This additive will be an effective and potential solution for cutting down green house gas and toxic emissions of engine exhaust.</p> <p>&nbsp;</p> Dinh Long HOANG Copyright (c) 2021 Dinh Long HOANG https://spast.org/techrep/article/view/1005 Sat, 18 Sep 2021 00:00:00 +0000 Higher-fidelity CFD Tools for Conceptual Design of Supersonic Business Jets https://spast.org/techrep/article/view/1199 <p>Business jets operating in the supersonic regime is the driving force for the next generation civil transport industry. The conceptual design study of supersonic business jets, so far has been largely performed through development of low-fidelity computational tools. Examples of low-fidelity tools implemented in recent studies are multi-disciplinary optimization frameworks by Sun and Smith [1] and Sun and Smith [2]. The problem with such tools is that they provide only low-fidelity results.</p> <p>A novel approach proposed is the use of Computational Fluid Dynamics earlier in mission study phases to provide more robust approach to conceptual design. Such a methodology can be successfully realized through the utilization of advancement in technology such as automated CFD meshing, increased computational resource and speeds.</p> <p>This research aims to develop new technology and new design framework to realize more robust approaches to supersonic jet design earlier in the conceptual design stages through the implementation of CFD. The idea is to develop highly efficient design concepts with the introduction of new, advanced geometries. There is potential to investigate low drag, low heat transfer solutions in aerospike design. Supersonic business jets have so far been developed with aerospikes that introduces an oblique shock in front of the blunt nose typical of all modern supersonic aircrafts. The presence of an aerospike reduces the aerodynamic and heat loads on the nose cone thereby reduces the chance of damage to the electronics in the nose cone. The geometry of spike can be altered such that more efficient designs can be introduced.</p> <p>In the proposed research, the extensive geometric space consisting of spike length, thickness, fineness ratio which has not been dealt in earlier studies will be fully explored. The influence of aerodisk shapes and the cause of unsteadiness which have not been fully understood will be investigated. The following are the research questions of this research.</p> <ol> <li>What is the effect of spike length on the aerodynamic drag at high Mach numbers?</li> <li>What is the effect of spike geometry on the aerodynamic drag/heat transfer at high Mach numbers?</li> <li>What is the effect of Reynolds number variation on aerodynamic drag?</li> <li>What is the effect of angle of attack of aircraft on drag and heat transfer?</li> </ol> <p>The proposed approach is the reduction of pressures behind shocks through the modifications in geometry of aerospikes. A generic model of a supersonic business jet will be created or assumed from existing designs. This generic model aircraft could be created using CAD and fitted with an aerospike in front of the nose cone. The aerospike could be in the shape as illustrated in Fig. 1.</p> <p>A spike of proper length creates a conical region of separated flow ahead of the body shielding it from the high-speed flow. The pressures and enthalpy behind the oblique shock created by the spike is lower than that of a normal shock. Use of modified spike geometries such as an aerodisk allows a fixed length spike to be effective over a wide range of velocities. The net effect is reduction in drag as well as temperature in front of the nose. However, the flow field is complex with presence of expansion, separation and reattachment shocks. Moreover, unsteadiness can occur due to the change in spike length, and shape. For non-zero angles of attack, unsteady vortices could be formed which may result in structural fatigue. As the angle of attack increases, the drag increases drastically resulting in reduction in effectiveness of spike. First results from 2D simulations are provided in Fig. 2 and Fig. 3.</p> <p>In the proposed research, the extensive geometric space consisting of spike length, thickness, fineness ratio which has not been dealt in earlier studies will be fully explored. The influence of aerodisk shapes and the cause of unsteadiness which have not been fully understood will be studied. The effect of following parameters on the unsteady flow of aerospike will be studied - spike length, spike head geometry, Reynolds number and angle of attack. The contributions and expected output of this research are:</p> <ul> <li>Development of new technology in aerospike design that significantly reduces drag and heat loads as compared to present designs.</li> <li>A new design framework that provides high fidelity design solutions at relatively lower computational cost</li> </ul> <p>A novel approach that aims to use CFD early in mission study phases to provide more robust approach to conceptual design is thus proposed which helps to develop new technology and new design framework to realize more robust approaches to supersonic jet design.</p> Nivedha Govindarajan, Abhinav Jayaswal, Katari Gaurav, Dr. Aravind Seeni Copyright (c) 2021 Nivedha Govindarajan, Abhinav Jayaswal, Katari Gaurav, Dr. Aravind Seeni https://spast.org/techrep/article/view/1199 Fri, 24 Sep 2021 00:00:00 +0000 Study of on-board hydrogen-rich gas generation for gasoline engine by gasoline steam reforming with exhaust gas recovery https://spast.org/techrep/article/view/809 <p><strong>Abstract </strong></p> <p>The increase in number of vehicles and propulsion equipment equipped with traditional internal combustion (IC) engines has been causing fast depletion of fossil fuel resources and increasing environmental pollution. These have pushed researchers to investigate clean alternative fuels for IC engines to overcome the problems. Among of such fuels, hydrogen has been known as a prominent one, but since hydrogen has a very low energy density on volume basis compared with gasoline and diesel fuel, hydrogen engines produce a lower power output than gasoline engines [1]. Therefore, researchers are more interested in use of hydrogen as an additional fuel to improve primary fuel combustion process. In case of gasoline engine, hydrogen addition has been proved reducing not only the fuel consumption, but also toxic emissions [2, 3]. However, the storage, distribution and delivery of hydrogen to vehicle engines meet many difficulties because hydrogen is a very light gas [1]. As a result, on-board hydrogen-rich gas generation by liquid fuel steam reforming is very necessary. For gasoline engine application, gasoline would be the most suitable fuel for reforming as its energy density is high and there is no need to use another fuel tank [4].</p> <p>On-board fuel reforming with exhaust energy recovery is significantly important since it increases the thermochemical energy of reformate by recovering the thermal energy of hot exhaust stream via endothermic catalytic reforming reaction. Taking advantage of exhaust gas energy for reformer heating may generate H<sub>2</sub> with high process efficiency since the exhaust gas energy normally represents 15%-25% of the total heat energy released from engine fuel combustion. However, what hydrogen yield that can be achieved is very important and should be studied to add to the engine for improvement of its performance and emissions.</p> <p>The objective of this study is to investigate the potential for hydrogen-rich gas generation for gasoline engine by on-board gasoline steam reforming via exhaust heat recovery. The study was experimentally conducted on-board of a motorcycle gasoline engine in a laboratory combined with modelling. Modelling study is to determine the optimum feedstock condition for high hydrogen yield while experiment is to confirm the solution of the study.</p> <p>Figure 1 shows the schematic layout of experimental set-up, in which the test engine is mounted on a hydraulic engine testbed named Didacta T101D. It is a Honda Wave Alpha motorcycle engine with swept volume of 100 cm<sup>3</sup>, power output of 6.5 kW at 7500 rpm. &nbsp;It is also equipped with a reformer whose design characteristics are shown in Figure 2. It is a fix bed catalyst with total catalyst volume of 140 cm<sup>3</sup> divided into 7 tube of 8cm length of each. The reformer is loaded with Nickel catalyst. The mixer volume of the reformer is loaded with alumina particle to improve the evaporation and mixing of fuel and water vapour. Other devices for metering fuel and water into the reformer and measuring temperature, flowrate and concentration of gas before and after the reformer are also shown in the figure.</p> <p>In modelling study, heat transfer in the exhaust pipe and the reformer as well as kinetic chemical reactions of gasoline steam reforming were addressed to determine the effect of feedstock to the reformer (water flowrate and fuel flowrate) and engine operating conditions on reformate gas product, especially on hydrogen yield, and determine the optimum conditions for highest hydrogen yield. Because gasoline is a mixture of many hydrocarbons and it has similar properties compared with isooctane C<sub>8</sub>H<sub>18</sub>, in this study, isooctane was used in place of gasoline for mathematical models to simplify the study.</p> <p>The reforming models were developed based on the reaction schemes and kinetic mechanisms proposed by Manuel Pacheco et al [4]. The models were coded using Fortran language to solve for temperature and reformate product concentration. The result indicated that the highest fuel conversion efficiency and highest hydrogen yield were achieved at engine full load at 7500rpm, with fuel supply to the reformer at the flowrate of 110g/h, mass water to gasoline ratio of 3.5. Under these conditions, the fuel conversion efficiency reaches 80% as shown in Fig. 3 while hydrogen&nbsp; yield reaches 0.14 mol/g gasoline as shown in Fig. 4 equivalent to 30.8 g/h.</p> <table> <tbody> <tr> <td width="22">&nbsp;</td> <td width="342">&nbsp;</td> <td width="5">&nbsp;</td> <td width="314">&nbsp;</td> <td width="38">&nbsp;</td> </tr> <tr> <td>&nbsp;</td> <td rowspan="3">&nbsp;</td> </tr> <tr> <td>&nbsp;</td> <td colspan="2">&nbsp;</td> <td>&nbsp;</td> </tr> <tr> <td>&nbsp;</td> </tr> <tr> <td>&nbsp;</td> </tr> <tr> <td>&nbsp;</td> <td colspan="2">&nbsp;</td> </tr> </tbody> </table> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>Figure 5 compares the predicted and measured component concentration of reformate gas product at engine full load at 7500rpm, with fuel supply to the reformer at the flowrate of 110g/h, mass water to gasoline ratio of 3.5. It can be seen that the predicted results were quite agree with the measured data; the hydrogen concentration nearly reaches 50%.</p> <p>In brieft, it can be concluded that on-board hydrogen-rich gas generation for gasoline engine by on-board gasoline steam reforming has been studied based on modelling and experiment. The optimum conditions for high fuel conversion and high hydrogen yield at engine full load are with W/F of 3.5:1 in mass basis under fuel supply at flowrate of 110 g/h. Under these conditions, gasoline conversion of up to 80% and H<sub>2</sub> concentration of up to 46% are achieved and 1 gram of gasoline can produce 0.14 moles of hydrogen, equivalent to 30.8g/h. The study confirms that on-board gasoline steam reforming taking advantage of engine exhaust gas energy is a convenient and effective method to produce hydrogen-rich gas for engine application.</p> Dinh Long HOANG Copyright (c) 2021 Dinh Long HOANG https://spast.org/techrep/article/view/809 Thu, 16 Sep 2021 00:00:00 +0000 Study on the Effect of Ventilation on Air Quality in Vehicle Cabin https://spast.org/techrep/article/view/1908 <p>Recirculation of air within a vehicle is an excellent approach to limit particle pollution and enhance air conditioner cooling efficiency. Nevertheless, the prolonged use of recirculation air within a vehicle might create high carbon dioxide (CO<sub>2</sub>) levels due to human exhalation and the lack of fresh air. However, using outside air (OSA) mode exposes occupants to roadway contaminants since outside air enters into the vehicle cabin. The occupants' comfort level can be influenced by the quality of air in the vehicle cabin. A major source of exposure to multiple air contaminants has been established in-cabin microenvironments, such as particulate matter (PM), the total volatile organic compound (TVOC) and carbon dioxide (CO<sub>2</sub>) concentration [1][2][3]. Hence, increased levels of air quality can cause a health risk. This is already one of road safety's most serious concerns. Although the adverse effects of outdoor pollutants have been given significant attention, there has been a dearth of understanding on the impact on the car occupants from indoor air pollution and quality. This study aims to provide information for drivers or passengers on the air quality in-cabin as there are insufficient data on air quality in-cabin private cars in Malaysia. The objectives of this work are (1) to investigate the concentration of the accumulated CO<sub>2</sub> levels in the vehicle cabin continuously while the heating, ventilation, and air conditioning (HVAC) system is set to different ventilation modes with the different number of occupants, car speeds and car cabin size, (2) to identify air quality in terms of the volatile organic compound (VOC) and particulate matter (PM) in the cabin with different conditions, and (3) to analyse the CO<sub>2</sub> concentration decay of a parked vehicle with the engine and the HVAC system switched off. The strategies proposed to experiment are by using two modes of ventilation, recirculation (RC) mode and outside air (OSA) mode as shown in Fig. 1.</p> <p>Fig. 1. Types of ventilation in vehicle</p> <p>This research work-study is focused on examining the air quality observed under the HVAC system with the RC mode compared to other ventilation options such as OSA mode. A few scopes of the study were introduced, (1) the study is limited to sites in Malaysia at close to sea level, (2) two different sizes of vehicles are used; small and mid-size cars (3) the number of vehicle occupants is set for 1 person, 2 persons and 4 persons. No history of smoking, no cardiopulmonary disorders such as coronary heart disease, hypertension, diabetes, obesity and other serious diseases were the selection criterion for the car occupants. The occupants are limited to Malaysian who are typically Asian, and (4) the research is conducted by experimental procedure only and not a simulation. The results of the experiment show that the magnitudes of peak CO<sub>2</sub> cabin concentrations are greater at the stationary car than at car speeds of 50 km/h. The higher the number the occupants in a vehicle, the shorter the time taken to reach an acceptable 1200 ppm level of CO<sub>2</sub>. The data also shows that the bigger the cabin area, the slower the accumulation of CO<sub>2</sub>. Besides that, the PM in the congested road is higher than in the non-congested road. Then, the increase of temperature in-car cabin can affect the concentrations of VOCs. Lastly, when cars are parked for an extended period, the CO<sub>2</sub> concentration steadily decreases and eventually returns to an acceptable level.</p> Muhammad Khairul Adha Mohamad Zali, Shaharin Anwar Sulaiman, Badrul Rezza Hakim Burham Copyright (c) 2021 Muhammad Khairul Adha Mohamad Zali, Shaharin Anwar Sulaiman, Badrul Rezza Hakim Burham https://spast.org/techrep/article/view/1908 Sat, 09 Oct 2021 00:00:00 +0000 Design of a triple band slotted Microstrip Patch Antenna for both C-band and X-band Applications https://spast.org/techrep/article/view/2103 <p>The modern wireless communication systems stand in need of elevated gain, wide bandwidth, broadband range applications, and compact antennas having the intention of imparting the execution enhancement above a wide range of frequencies. In spite of microstrip patch antennas have multifarious benefits, they do have some significant disbenefit. Several main obstructions with patch antennas are their innately single band, low gain, less directivity performance as a consequence of its resonant nature in the low range [1]. A wide range of Applications of antenna configuration is the success of any research work. &nbsp;C band is used in satellite communication, WiMAX, WLAN, Wi-Fi applications. X-band is the frequency band in the microwave frequency region of the radio spectrum. The X-band finds its applications in different fields like radar engineering, satellite communication, space-crafts, wireless computer networks, etc. The frequency range of the X-band is 7.0 GHz to 11.2 GHz in radar engineering, radars that operate in this range are generally used as police radars for measuring the speed of the vehicles, for military applications, for navigation purposes, and in determining the weather forecast. IEEE specified frequency range of X-band is 8.0 GHz to 12.0 GHz [2-5]. One of the great challenges in the antenna is to achieving the application in C-band and X-band range at the same antenna configuration at 2.4 GHz working frequency. These are some challenges to attain an efficient antenna. In order to achieve the above-said goal, in this research paper, a slotted microstrip patch antenna is proposed. On account of this essential, a triple-band rectangular microstrip antenna with six equal-length rectangular slots is offered. A specific investigation is carried out to review the outcomes of rectangular slots that get on multi resonant frequencies which cover C-band and X-band, enhanced directivity and gain are bestowed. In this analysis, two phases of microstrip antenna designs are enclosed. The first is the evaluation of the antenna without utilized slot cutting techniques and the second phase is the investigation and design of an antenna used six equal rectangular slot cuts on the patch that works at the central frequency of 2.4 GHz. The attributes of antenna such as directivity, gain, S parameter, VSWR has been examined and related between without and with the slots cutting microstrip antenna via high-frequency structure simulator (HFSS). The considered antenna attained single band without slot at 11.36 GHz with a return loss of -14.7663, VSWR of 3, gain of 5.2278 dB, directivity of 8.7891 dB while the antenna achieved triple-band frequency ranges with slots and also it exhibits the enhanced directivities of 4.6843 dB, 9.0304 dB, 7.8466 dB, boosted gains of 1.9649 dB, 1.9649 dB, 3.5968 dB, 5.4552 dB at 7.16 GHz, 9.82 GHz, 12.9 GHz frequencies respectively also the VSWR is 1. The novelty of this work is a small size antenna that resonates at three bands that covers C-band and X-Band. It is reported that the slot cutting technique is the best tactic to tune the characteristics of antenna such as the enhancement of directivity, gain, VSWR also it causes to yield multi resonant frequencies</p> P. Mercy Copyright (c) 2021 P. Mercy https://spast.org/techrep/article/view/2103 Fri, 08 Oct 2021 00:00:00 +0000 PEDESTRIAN HEAD IMPACT ANALYSIS ON A VEHICLE AND MEASURES TO REDUCE HIC VALUE https://spast.org/techrep/article/view/2175 <p>Many pedestrians suffer fatal injuries in traffic accidents with vehicles in India and all over the world, methods of evaluating pedestrian protection are being investigated along with various technologies for improving the energy-absorbing characteristics of the vehicle body[1-2]. The major fatalities are because of the severe injuries on the Human head. So the need for decreasing injuries on the Head is of prime importance. Human body Kinematics plays a very important role in the severity of the injury and the kinematics need to be controlled for injury reduction [3] . This paper worked out on the analysis of pedestrian head impact behavior on a vehicle and technique to reduce HIC (Head Impact Criteria) value. It also describes two future pedestrian protection technologies that have less influence on vehicle design. One is a “rear-rising hood” that increases the energy-absorbing space at the time of a vehicle-pedestrian collision. The other is an “airbag system for controlling pedestrian collision kinematics” that can help reduce the head impact velocity against the vehicle by helping to control the kinematics of a pedestrian following a collision with a vehicle.</p> SANTOSH KUMAR TRIPATHY Copyright (c) 2021 SANTOSH KUMAR TRIPATHY https://spast.org/techrep/article/view/2175 Fri, 05 Nov 2021 00:00:00 +0000 DESIGN MECHANISISM AND WORKING OF A SWASHPLATE https://spast.org/techrep/article/view/2365 <p>The complexity of the mechanism of the swashplate in a helicopter is the base for the eagerness and interest that attracts the people to know about it. The design itself has its complexity and the manufacturing and assembling of the parts onto the helicopter is quite challenging for people. We have designed a swashplate with conventional methods and have tried to analyze the working of each part and have come up with a model to demonstrate the same. Using conventional RC controls we will be demonstrating the working and mechanism of the swashplate.</p> Judy Rabaa, ASHOK KUPPUSAMY Copyright (c) 2021 Judy Rabaa, ASHOK KUPPUSAMY https://spast.org/techrep/article/view/2365 Fri, 08 Oct 2021 00:00:00 +0000 A vehicle has an engine as its Investigation on Thermal Analysis of Circular Fins Using ANSYS simulation https://spast.org/techrep/article/view/2310 <p>A vehicle has an engine as its most significant part, which is subject to high temperature assortments and heat transfer. At the point, when fuel is singed in a an engine, heat is delivered and fins are essentially used to chill off the part, so that the temperature maintained within the designed temperature. Fins are generally made on the external circumference of the engine cylinder which is employed to extend the speedy removal of hotness from the surface by fins through a combination of conduction and convection mode of heat transfer. Thermal analysis/examination on the engine cylinder is one of the valuable techniques to know the hotness spread inside the cylinder. Finite element analysis (FEA) can moreover be useful in choosing the execution, especially conductivity inclinations. The fundamental point of the present research paper is to examine the thermal nature by changing geometry profile of cylinder blades/fins by employing Ansys workbench. The 3D model of the calculations is made utilizing fusion 360 and along its thermal analysis is examined by employing Ansys simulation. The variety of temperature dispersion after some time is of interest in numerous applications, especially in cooling. The materials employed for assembling cylinder body is Aluminum (Al) alloy, by comparing between AA 6061 and alloy 61S in this research work whose thermal conductivity is 160 – 170 W/mK. From this research output, the AA 6061 or alloy 61S has better results than the conventional aluminium in various thermal properties and hence it is great replacement of conventional aluminium material with AA 6061 or alloy 61S in the circular fins in near future. Data we have gathered for AA 6061 Aluminium alloy.<br />Aluminium alloy is used as a fin material because of its light weight, economical and better heat dissipation capabilities.<br />AA 6061 systems offer superior combination of properties in such a manner that today no existing monolithic material can rival.</p> <p>Also, aluminium alloys have more better features which are has excellent resistance to corrosion<br />The thermal conductivity of aluminium is about three times greater than that of steel</p> Abhay Patel Copyright (c) 2021 Abhay Patel https://spast.org/techrep/article/view/2310 Thu, 07 Oct 2021 00:00:00 +0000 Comparative study on Thermal Analysis of Extended Surface Using ANSYS simulation https://spast.org/techrep/article/view/2547 <p>Extended surface are heat exchangers generally made on the external circumference of <br>an object that are mainly used to enhance the heat transfer rates through a combination of <br>conduction and convection mode of heat transfer. In general, extended surface are made up of <br>the materials whose thermal conductivity is maximum to facilitate more amount of heat transfer<br>to or from the environment and also available in different profiles with respect to the <br>applications of the components. Among the different types, the most commonly used are <br>longitudinal type of fins i.e. when the direction of flow of the fluid is parallel to the axis. In this <br>research work, an attempt has been made to compare three different profiles like rectangular, <br>trapezoidal and concave parabolic fins using ANSYS simulation software. Thermal analysis using <br>ANSYS simulation is one of the important techniques to analysis the efficiency of the fin with <br>different profiles. The model of the fin profiles is made by fusion 360 and the comparative study <br>on thermal analysis is carried by employing Ansys simulation. From this research output, the <br>trapezoidal profile of the extended surface has better results than the conventional rectangular<br>as well as concave parabolic in various thermal properties and hence it is great replacement of <br>in near future.</p> HRISHIKESH RAJESH KUMAR, Arun Antony M T , Shyam S Warrier , S. Senthur Prabu Copyright (c) 2021 HRISHIKESH RAJESH KUMAR, Arun Antony M T , Shyam S Warrier , S. Senthur Prabu https://spast.org/techrep/article/view/2547 Sun, 17 Oct 2021 00:00:00 +0000 TREADMILL ON WHEELS MODERN WAY OF TRAVELLING AND EXERCISE https://spast.org/techrep/article/view/2362 <p>Treadmill on wheels is new method for travelling/exercising. Treadmills are basically used for running or walking on the same place. Using the same principal, the device is brought in the motion. In this device when the user runs/walks on the treadmill the walking belt moves backward which cause in the activation of the motor which rotates the shaft of the rare wheel which is connected by the chain drive and the battery. The user’s efforts affect the motion of the bicycle so it’s known as the treadmill on wheels. The combination of the electric components and gears increases the speed of the device. Users may use this device for short distance travelling which will reduce their time and helps in the exercise and will help in reducing the pollution by reducing the use of the conventional fuel vehicles. The speed of the device may be controlled using the breaks. The rubber walking belt helps to avoid the sliding of the user from the walking platform. The moto behind this device is quicker walking and easier bicycle riding.</p> Pranavvswami Copyright (c) 2021 Pranavvswami https://spast.org/techrep/article/view/2362 Fri, 08 Oct 2021 00:00:00 +0000 MHD Pulsating flow and entropy analysis of micropolar nanofluid in a vertical channel with thermal radiation https://spast.org/techrep/article/view/2524 <p>In this paper, we explore the pulsating flow magneto-hydrodynamic (MHD) unsteady flow of a micropolar nanofluid in a vertical channel by applying Buongiorno’s nanofluid model with entropy analysis. The effects of Brownian motion, thermophoresis, and Joule heating (Ohmic heating) are taken into account. The considered model is important in the study of biological fluid modeling, polymer engineering, sediments in rivers, and nano-drug delivery. A perturbation approach is used to convert the partial differential equations (PDEs) into ordinary differential equations (ODEs), and are subsequently solved by adopting the shooting technique with the help of the Runge-Kutta fourth-order method. The flow variables like velocity, microrotation, temperature and nanoparticle concentration are graphically depicted and discussed in detail for different values of physical parameters.</p> <p>Nowadays, the scientific research of nanofluids is a highly recommended area in various domains such as mechanical systems, transformer cooling in vehicles, applications in biomedical, coolant systems, and so on. Nanofluids are a comparatively current category of heat transfer have fascinated much observation of researchers from previous generations around the globe. The section of nanofluids was first established by Choi [1]. To characterize a fluid including solid nanoparticles with a size typically of (1-100 nm) suspended in a fluid. Buongiorno [2] initialized the impacts of Brownian motion and thermophoresis diffusion are a major fact for the improvement of heat and mass transfer. Kumar et al. [3] examined the hydromagnetic pulsative flow of Casson nanofluid in a channel by using the Buongiorno model. The non-Newtonian fluid is observed as blood and it is classified as the micropolar fluid. The concept of the micropolar fluid model was primarily pioneered by Eringen in (1966) [4] and later extended into a thermo-micropolar fluid to explicate the properties of polymeric fluids, liquid crystals, colloidal suspensions, animal and human blood. In such fluid is characterized by microstructures, rigid and arbitrarily focused particles on microrotation of fluid components. Eringen [5,6] formulated a much complex structure for simulating effective micro-rheological properties and areas of applications in various industrial and engineering fields like chemical engineering, synovial fluid, biofluids, semi-circular canal fluids, gastric liquids, and slurry technologies.</p> RAJKUMAR D, Subramanyam Reddy Anala, Srinivas S, Jagadeshkumar K Copyright (c) 2021 RAJKUMAR D, Subramanyam Reddy Anala, Srinivas S, Jagadeshkumar K https://spast.org/techrep/article/view/2524 Sun, 17 Oct 2021 00:00:00 +0000 A comprehensive review on Involvement of drones in covid 19 pandemics https://spast.org/techrep/article/view/1042 <p>The core idea of the paper is to create a multi-purpose drone/unmanned aerial vehicle which are used to counter challenges faced by COVID-19. Our work is structured to give insights into our theory method with a constructive form of qualitative research. This work's main contribution lies in the comparative study of many research articles based on the use of drone in different fields specially in sanitization of a large area in a stipulated period&nbsp; , Thermal screening of people and storing their temperature recorded data in cloud, AI implementation in order to detect abnormal pattern of coughing, heart rate etc and delivery of medicines and necessary essential to quarantined people and migrants this will cause a large-scale implementation of drone delivery may drastically change the business, substituting hundreds of workers, fossil-fuel-powered delivery vehicles, traffic congestion, and centralised distribution centres of drone which performs point A to point B parcel delivery. The challenges faced by drone and its operators during active mission are studied. This study will help others who are new to drones in the covid and medical field.</p> <p>Keywords: Unmanned Arial vehicle, screening, artificial intelligence, UAS</p> Ruby Mishra, Santosh, Somesh Copyright (c) 2021 Ruby Mishra, Santosh, Somesh https://spast.org/techrep/article/view/1042 Mon, 20 Sep 2021 00:00:00 +0000 Experimental Study of Three Stream Coaxial Jets https://spast.org/techrep/article/view/1157 <p>A core Mach 2 jet from the convergent-divergent nozzle in the presence of two coaxial sonic streams from convergent nozzles was investigated experimentally at different nozzle pressure ratios. The jet field was visualized using shadowgraph for nozzle pressure ratio (NPR) 3 to 6. For a fixed core jet NPR, NPRs of coflow jets were varied from 3 to 6 (insteps of 1) and shadowgraph images were captured. From the visualization results, it was observed that the core length of Mach 2 jet for NPRs 3 to 6 increased with increasing coflow NPRs, indicating reduced mixing of controlled Mach 2 jet as compared to uncontrolled Mach 2 jet (without coflows). From the present study, it was clear that the use of two sonic coflows on Mach 2 jet would result in core elongation for all the NPRs thus acting as a mixing inhibitor, but the sonic coflows were found to weaken the waves in Mach 2 jet, which is advantageous from the aeroacoustic point of view.</p> Rajkumar Sundaram Copyright (c) 2021 Rajkumar Sundaram https://spast.org/techrep/article/view/1157 Fri, 24 Sep 2021 00:00:00 +0000 Study on Measurements of Flame Geometry by Schlieren and Direct Light Photography https://spast.org/techrep/article/view/2308 <p>As schlieren imaging continues to be used around the globe, many studies have also been done to modify the classic technique into something simpler yet reliable for research purposes. Despite its success throughout the centuries, the schlieren imaging has many limitations with one of them being its intricacy when setting it up, making it rather time consuming. Other limitations include the cost, portability, and field-of-view [1-2]. For years, researchers have come up with various new methods deriving from the classic schlieren to overcome those limitations. These modified setups are then called as “synthetic schlieren” as they stem and are altered from the classic setup, but their purpose does not deviate from the original, which is to visualize flows that are impossible for the human eyes to see [3]. Unfortunately, most of the past works revolved around overcoming the general problems of the classic technique and not enough experiment has been performed to assess the chance of substituting schlieren imaging with direct light imaging for the purpose of measuring flame geometry. In this study, the experiment focuses on direct light imaging – a simple setup that uses modern cameras. With how simple it is, it is hoped that the setup will be able to lift certain burdens that are faced by many researchers who uses the classic setup, if the experiment is deemed to be a success. The objective of this study is to compare the effectiveness of direct light imaging in capturing the propagation of flame as compared to schlieren imaging. Both the schlieren and direct light method are experimented to accomplish the objective of comparing the performance of direct light imaging to schlieren imaging. With how much cameras have advanced over the years, it is anticipated that flame images captured using direct light imaging will be decent enough for geometry analysis. Furthermore, the focus of this study is on the geometry of the flame, which is visible to cameras. Thus, this further increases the possibility of a positive outcome from the experiment. For direct light imaging, the setup is as simple as using a camera and a black screen. The setup is done in two settings – dark room and bright room – for the comparison of clarity in the images captured. For schlieren imaging, the setup is only done in one setting as the brightness of the room will not affect the clarity of the images due to the light source used in the setup. The type of flames that are focused on in this study are candle, stove, lighter, and flame ignited with hand sanitizer. Each flame type is fuelled by different fuel to observe the influence it has on the flame. The results between the setups are compared and it is shown that the direct light setup is as competent as the schlieren imaging in its ability to capture high-quality flame images. The results continue to show that flame analysis with direct light imaging is possible, and this could be the beginning of modern camera in the field of flame geometry research.</p> Olive Uyang David Ngau Copyright (c) 2021 Olive Uyang David Ngau https://spast.org/techrep/article/view/2308 Thu, 07 Oct 2021 00:00:00 +0000 Folding mechanism for wheelchair https://spast.org/techrep/article/view/1267 <p>In India, many people are suffering of temporary or permanent disabilities due to various reasons like illnesses or accidents. Due to which they are having difficulty or impossible in walking. That is why the use of a wheelchair is becoming essential. There are lots of wheelchairs are available which satisfying for most of the low and medium level disability situation. Specially now a days foldable wheelchairs are in demand due to its advantages like, easy to transport, less space need etc. However, available foldable wheelchairs having fixed mechanisms hence, it is difficult to change the mechanism in several conditions. For this It is proposed to a design of folding mechanism that can attach on the standard size wheelchair and can be replaced if any break down.</p> <p>The proposed design full fill with features light weight, portable and the Mechanism is compact and hence can operate by less effort. It can be used in institutions, offices, industries and at some homes. According to the tests conducted, the Mechanism can be mounted on wheelchair has a capacity of carrying a load of 100kg on flat surface.</p> Yashodhan, Dr. E. Vijayaragavan Copyright (c) 2021 Yashodhan, Dr. E. Vijayaragavan https://spast.org/techrep/article/view/1267 Thu, 30 Sep 2021 00:00:00 +0000 A Novel Approach of Multiphysics Modelling and Optimization of Gas Flow Characteristics of a Flowmetric based Gas Sensing Chamber https://spast.org/techrep/article/view/2840 <p>Gas sensing is a very vital and commonly adapted process in various industries and service sectors. The gas sensing can be as mundane as a pressure leak in an automotive tyre to as critical as a flammable, hazardous, or even toxic gas in environments where they find a huge requirement such as industries or in hospitals. It is highly crucial to detect the leakage of gases in these environments to maintain the operability of some systems or prevent catastrophic incidents in others. A variety of gas sensors have been developed to sense these gases present either individually or as a mixture with other gases. The reliability of a gas sensor is highly dependent on the gas sensor calibrating or testing chamber. The credibility of the gas sensing chamber would dictate the gas sensor's performance. A gas sensor needs to be observed or characterized for its characteristic such as sensitivity, selectivity, temperature-dependent response variation, sensing accuracy and precision, repeatability, response towards the exposed gas, response time, etc. These characteristics can be accurately studied only when the behavioural characteristics or the gas chamber is predetermined and well characterized. The paper intends to propose a flow metric-based gas sensing chamber as against the conventional volumetric chamber and presents the gas flow nature in the chamber [1]. The chamber is designed with a single inlet port and single exhaust vent or outlet port. The inlet port can be extended to handle multiple gas inlets. The gas inlet port angling also helps the input gases to mix before entering the chamber. The outlet port is positioned slightly elevated at the rear end of the chamber to facilitate the gas exhaust. Both the inlet and outlet ports are positioned in the direction of flow of the gas as shown in fig 1. A pair of baffle plates are provided at the entrance of the chamber, following the inlet ports. These baffle structures act as passive gas mixtures. The angle and number of baffle plates were again optimized to enhance the gas mixing. The turbulent flow from the baffle zone needs to be transformed into a laminar flow to improve the sensing by the sensor placed over the substrate [2]. The placement of the substrate holder with respect to the chamber dimensions, flow characteristics in the chamber has been optimized to provide a laminar flow over the substrate which would result in higher sensing ability of the gas sensor. The paper also deals with the boundary layer suppression, as shown in fig 2, to provide maximal gas flow over the substrate, thereby enhancing the chance of sensing by the gas sensor [3]. An integrated heater is also provided below the substrate holder which would be required since some gas sensors operate at high temperatures for their optimal performance [4]. Study on heat propagation from the heater onto the substrate holder is also involved. The flow characteristics of the entire chamber were analysed especially at the inlet port, over the substrate, and at the outlet port. Modelling, simulation and analysis of the gas sensing chamber was carried out in COMSOL Multiphysics software. The paper focuses on complete modelling of gas sensing chamber, fluid dynamic studies of the gas flow inside the chamber, optimal placement of substrate, optimal angling of the substrate facing the gas flow, and the heat propagation from the heater onto the substrate holder.</p> K Govardhan, S Muthuraja, A Nirmala Grace Copyright (c) 2021 K Govardhan, S Muthuraja, A Nirmala Grace https://spast.org/techrep/article/view/2840 Tue, 19 Oct 2021 00:00:00 +0000 Wire ECM Process: A brief review of the Process & Recent Advancements https://spast.org/techrep/article/view/1833 <p>Electrochemical machining has gained the attention of various researchers in the last few decades. This process finds its application in various industries like, biomedical industry, electronic industry, marine industry, aerospace industry, etc.&nbsp; Zero tool wear, absence of HAZ, are some of the advantages of ECM process. Since the metal is removed ion by ion, so workpiece’s hardness does not put any restriction on the machining.&nbsp; Wire Electrochemical process, variant of ECM process has also gained popularity in the recent years. The wire as tool in ECM process helps in cutting of intricate shapes in a quite easy manner.&nbsp; The following study is focused on the overall recent advancements in Wire ECM process. This review article also focuses on the modern trend and achievements that has been made in the Wire ECM field.&nbsp; Apart from discussing literature survey of Wire ECM process, this article also gives an overall in depth critical review of the science behind the process. Various technological advancements reported in the field of Wire ECM process and state of the art industrial application are reviewed in the article, which will help the researchers around the globe to use the process to its full potential.</p> <p><em>Keywords</em>: WECM, Passivation layer, Electrochemical dissolution, Multi-wire ECM, Side gap.</p> AAKASH TYAGI Copyright (c) 2021 AAKASH TYAGI https://spast.org/techrep/article/view/1833 Sat, 09 Oct 2021 00:00:00 +0000 Investigation of Diesel Engine Combustion Characteristics for Varying Nozzle Depth at Different Spray Angles https://spast.org/techrep/article/view/1440 <p>The demand for petroleum-derived fuels is increasing every day despite their speculations about the exhaustion of petroleum fuel. Petroleum-derived fuels are classified as a suspect element for humans due to their known primary adverse effects on the environment. The concern is that the demand for petroleum fuel will rise along with the market price. Researchers around the world focus on reducing the harmful effects of petroleum fuel or finding some other substitute for petroleum fuels. This research focuses on the reduction of harmful gases from the exhaust gases of a diesel engine. This research included a detailed analysis of combustion parameters. A Kirloskar single cylinder diesel engine (model TV-1) was selected for simulation using commercially available AVL FIRE software. The published articles indicate the operating conditions and limitations of the single cylinder diesel engine. The geometry of the hemispherical cup piston is generated and networked in software, then the search is processed by selecting three different spray angles, such as 120<sup> o</sup>, 140<sup> o</sup> and 160<sup> o</sup>. The standard spray angle is 120 degrees. In addition, four nozzle depths are included in the search to analyze the effect of nozzle depth on combustion parameters. The nozzles are available in four depths: 0.5 mm, 1 mm, 1.5 mm and 2 mm. while the nozzle depth is 1mm standard nozzle depth. Four nozzle depths with spray angles of 120 °, 140 ° and 160 ° are examined. The results returned the combustion parameter and depend on the spray angle and the depth of the nozzle. To obtain an adequate combustion result from the above scenario, some trade-offs in terms of combustion parameters need to be considered.</p> Dr. Rahul Kumar Singh Copyright (c) 2021 Dr. Rahul Kumar Singh https://spast.org/techrep/article/view/1440 Thu, 07 Oct 2021 00:00:00 +0000 A Study on Performance Evaluation and Thermal Analysis of an Automobile Radiator https://spast.org/techrep/article/view/2609 <p>A car is one of the best feats of mechanical engineering and design. A car is run by a power source that provides necessary and required energy to translate or move and the power source is an engine. The engine is a mechanical marvel that converts chemical energy to mechanical movement. During this process, there is generation as well as the exchange of heat that happens continuously to keep the car running. Over time the engine heats up, i.e. most of this chemical energy is lost to the environment as heat which reduces the efficiency of the engine significantly. Here the radiator is an important component that makes sure that the heat transfer process should be more efficient. A radiator is a type of heat exchanger that is used to transfer heat energy from one medium to the other. In a car, the radiator functions to monitor and regulate the engine temperature to prevent it from overheating thus improving the efficiency of the engine. As the engine runs it gets heated up, the coolant is circulated around the engine in the cooling water jackets which absorbs heat. This coolant further flows through the tubes of the radiator where it is cooled by the fan and exits the radiator to a lower temperature than entered. The radiator provides a high surface area for better dissipation of heat from the coolant. Here three types of heat transfer occur and they are conduction between the fins of the radiator and the tube that carries the coolant, convection through the coolant and convection of the heat dissipated by the coolant through the air. In the present research work, the CAD model of the automobile radiator is made by using the SolidWorks software. A study has been made on the performance evaluation of the radiator and with the help of Ansys workbench the thermal analysis is carried out by considering the both heat/cold boundary conditions to optimize for better functioning of the radiator in extreme temperature conditions. From this research output, the automobile radiator shows the better results in various thermal properties on different working temperatures.</p> Atharva Gurjar, Mohammed Moinuddin Shaikh, Siddhesh Ambilduke, S. Senthur Prabu Copyright (c) 2021 Atharva Gurjar, Mohammed Moinuddin Shaikh, Siddhesh Ambilduke, S. Senthur Prabu https://spast.org/techrep/article/view/2609 Sun, 17 Oct 2021 00:00:00 +0000 Development and Trend of Condition Monitoring and Fault Diagnosis https://spast.org/techrep/article/view/2246 <p>Machines are widely used in various industrial applications. During operation all machines are subjected to fatigue, wear, deformation, etc. Due to these effects there is an increase in the clearance between mating parts, unbalance in rotor, misalignment in shafts-all leading to an increase in the level of vibration. Increase in vibration level leading ultimately to the failure or breakdown of the machine. The performance and quality of the machine directly affects on its life and reliability. Machine condition monitoring and fault diagnosis are techniques which are commonly employed by processing and manufacturing facilities to monitor the reliability, availability, and performance of machines. Fault diagnosis by monitoring machine vibration is proven to be the most effective method for machinery condition monitoring. Fault diagnosis provides the condition for fault tolerance, reliability or security, which constitute fundamental design features in complex engineering systems. This paper provides an overview of developments and progress in condition monitoring, diagnostics and failure detection philosophy and concepts. It is important to have an effective bearing condition monitoring and fault diagnosis system in place so that emerging bearing faults can be analysed and correctly detected on time to prevent them from breakdown further to cause damage to a machine. Vibration analysis &nbsp;provide a good basis for condition monitoring, as elevated signal levels are detected in fault cases. This paper provide a review on the most recent progress in condition monitoring methods and fault detection techniques.</p> Nandini Pratap Chavan Copyright (c) 2021 Nandini Pratap Chavan https://spast.org/techrep/article/view/2246 Thu, 07 Oct 2021 00:00:00 +0000 Smart manufacturing a revolution technique towards application of industry 4.0 approach https://spast.org/techrep/article/view/2360 <p><strong>Keywords:</strong></p> <p><strong>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</strong>Learning factory, lean automation, Industrial revolution, lean tech.</p> Sumit Pawar Copyright (c) 2021 Sumit Pawar https://spast.org/techrep/article/view/2360 Fri, 08 Oct 2021 00:00:00 +0000 The A REVIEW OF CARBON FIBER MATERIAL https://spast.org/techrep/article/view/2857 <p>In present scenario, light weighting becomes a main issue for energy efficiency in automotive industry. The emission of gases and fuel efficiency of vehicles are two important issues. The best way to improve the fuel efficiency is to decrease the weight of vehicle parts. Research and development played an important role in lightweight materials for decreasing cost, increasing ability to be recycled, enabling their integration into vehicles, and maximizing their fuel economy efficacy. There arises a need for developing a novel generation of materials that will combine both weight reduction and safety issues. The application of carbon fibre reinforced plastic material offers the best lightweight potential to realize lightweight concepts. Carbon fibre reinforced plastic has outstanding specific stiffness, specific strength, and fatigue properties compared to commonly used metals. In automotive industry, the advantages of carbon fiber reinforced plastic are reduction in weight, part integration and reduction, crashworthiness, durability, toughness, and aesthetic appealing. Carbon fiber reinforced plastic is a composite material that has been used extensively in various applications such as aerospace industry, sports equipment, oil and gas industry, and automotive industry. Keeping in view the aforementioned advantages of carbon fiber reinforced plastic, the authors have presented a brief review on carbon fibre for automotive industrial applications.</p> <p><u>KEY WORDS:</u></p> <p>&nbsp;</p> <p>To overcome the problem of energy efficiency. Lightweight, higher strength.</p> Arun Dadasaheb Wakekar Arun Dadasaheb Wakekar Copyright (c) 2021 Arun Dadasaheb Wakekar Arun Dadasaheb Wakekar https://spast.org/techrep/article/view/2857 Tue, 19 Oct 2021 00:00:00 +0000 An Investigation on Pulse Current Nickel Plating on Copper Substrate https://spast.org/techrep/article/view/784 <p>The synthesis of micro and nano sized nickel crystals by electrodeposition has been studied for more than a decade now. A lot of attention is being spent on controlling the process parameters, adjusting the bath composition and developing new additives for the developing a good quality coat. In this paper bulk nanocrystalline nickel was developed on copper substrate using pulsating current supply. Pulse current was applied at a cycle time of 240 sec, 50% duty cycle and 0.00417 Hz frequency. Surface morphologies, grain sizes, textures and hardness were studied for different pulses with varying peak current. Energy Dispersive Spectroscopy (EDS) results represents a good layer of nickel coating developed on copper substrate. Coating weight and thickness is observed to increase with rise in peak current. Microstructure captured by Field Emission Scanning Electron Microscopy (FESEM) technique represented a uniform coating developed comprising of primary (fine) and secondary (coarse) granules of nickel. The hard primary and secondary granules deposited on the surface of the copper substrate tends to increase the hardness. From the results it is observed that there is about 8% increase in hardness of nickel pulse plated sample compared to copper substrate. Nickel coating on copper is largely used for copper mould applications in continuous casting process.</p> Canute Sherwin, Suma Bhat Copyright (c) 2021 Canute Sherwin, Suma Bhat https://spast.org/techrep/article/view/784 Sat, 18 Sep 2021 00:00:00 +0000 Studies on Bending Properties of AA 6061-T6 Aluminium alloy joined by Friction Stir Welding https://spast.org/techrep/article/view/2563 <p>Nowadays for various engineering applications AA6061-T6 aluminium-magnesium (AL-Mg)<br>alloys are widely used, which is due to its light weight and superior properties as compared to other<br>aluminium alloys. Ferrous and non-ferrous metal joining process is most complex and tedious process<br>in various precision industries like automobile, aerospace, railway and marine industries [1-2]. This is<br>due to rigid tolerances and the prerequisite of different product assembly. The Friction Stir<br>Welding (FSW) of AA6061-T6 aluminium-magnesium alloy grade has influenced substantial scientific<br>and industrial importance, because it has a potential to transform the welded product with a good<br>quality joint. The joining of Al-Mg alloy (AA6061-T6) is a challenging task by conventional fusion<br>welding process. This is mainly due to its various mechanical and metallurgical properties. Therefore,<br>in the present work it has been considered to join aluminium-magnesium alloys using FSW [3-4].<br>Particularly observation has been made about material flow behaviour and effect of process<br>parameters on various mechanical properties and associated defects during FSW. Experimental<br>results are presented for weld property comparison. It can be concluded that FSW can be effectively<br>used to produce defect free welds, which are having better bending properties as compared to the<br>welds produced by other conventional welding process [5-7].</p> Yogeesha C, Suresha C N Copyright (c) 2021 Yogeesha C, Suresha C N https://spast.org/techrep/article/view/2563 Sun, 17 Oct 2021 00:00:00 +0000 Empirical Evidences of Solar Desalination Methodologies https://spast.org/techrep/article/view/925 <p>Desalination technology has played a significant role in solving the water scarcity in the region<br>leading to sustainable development. As shortage develops and with propels in desalination<br>innovation and decreases underway cost, strategy producers all throughout the planet of world<br>are properly inquiring regardless of whether desalination should have an influence in shutting<br>the gap among organic market in future years. Although a large portion of the stock-request<br>gap arrangements will, in any case come from the customary organic market side<br>administration choices. This study covers and explains different solar desalination<br>technologies in dealing with water problems and the best suitable methods. A technoeconomic<br>evaluation and review of the costing aspects and the main parameters influencing<br>the total water cost produced by different desalination technologies are herein presented in<br>detail. Some recent developments, such as the increase of unit capacity, improvements in<br>process design and materials, and the use of hybrid systems have contributed to cost<br>reduction as well as reduction in energy consumption. The development of new and emerging<br>low-energy desalination technologies, such as adsorption desalination, will have an impact on<br>cost variation estimation in the future.</p> Sahil Naghate Copyright (c) 2021 Sahil Naghate https://spast.org/techrep/article/view/925 Thu, 16 Sep 2021 00:00:00 +0000 Experimental and Thermal Analysis of Desktop FDM 3D Printer "Ender 3" and "CR-10S" Hot ends. https://spast.org/techrep/article/view/2631 <p><span style="font-weight: 400;">Nowadays, the desktop 3D printers are inevitable in computer applications and widely used in multiple applications like in homes, offices, and in several additive manufacturing business sectors, etc. A wide variety of filaments like PLA+, ABS, PETG, TPU, etc, are now being used. These filaments require different temperatures to print.&nbsp; The hot end of a printer plays a crucial role in the extrusion of these filaments for printing. It is the part where the filament is brought to a semi-solid state, to extrude and deposit the filament in layers. In this research study, the hot end of "Ender 3" and "CR-10S" will be modelled using fusion 360 solid workspace to build the components and with the help of Ansys software the thermal analysis is carried out by considering the extreme temperature conditions by simulation workspace. So to optimize this problem of temperature gradient, the different boundary conditions such as heat/cold conditions, will be considered during analysis. Alongside, the simulation result also compared with manual experimental readings. From this research output, the simulation result shows better results in extreme temperature conditions in various thermal properties and hence the results will support better for the 3D printer manufacturer in near future.</span></p> Havish Karanam, M.S.Kiran Karthik Copyright (c) 2021 Havish Karanam, M.S.Kiran Karthik https://spast.org/techrep/article/view/2631 Sun, 17 Oct 2021 00:00:00 +0000 Experimental Study of Three Stream Coaxial Jets https://spast.org/techrep/article/view/1155 <p><strong>Abstract</strong></p> <p>A core Mach 2 jet from the convergent-divergent nozzle in the presence of two coaxial sonic streams from convergent nozzles was investigated experimentally at different nozzle pressure ratios. The jet field was visualized using shadowgraph for nozzle pressure ratio (NPR) 3 to 6. For a fixed core jet NPR, NPRs of coflow jets were varied from 3 to 6 (insteps of 1) and shadowgraph images were captured. From the visualization results, it was observed that the core length of Mach 2 jet for NPRs 3 to 6 increased with increasing coflow NPRs, indicating reduced mixing of controlled Mach 2 jet as compared to uncontrolled Mach 2 jet (without coflows). From the present study, it was clear that the use of two sonic coflows on Mach 2 jet would result in core elongation for all the NPRs thus acting as a mixing inhibitor, but the sonic coflows were found to weaken the waves in Mach 2 jet, which is advantageous from the aeroacoustic point of view.</p> Rajkumar Sundaram Copyright (c) 2021 Rajkumar Sundaram https://spast.org/techrep/article/view/1155 Fri, 24 Sep 2021 00:00:00 +0000 Gadolinium nitrate decorated reduced graphene oxide structure and morphological studies for battery applications https://spast.org/techrep/article/view/1751 <p>Graphene-based materials and their compounds have found promising for extensive applications such as membranes [1], solar cells [2], sensors [3], super capacitors [4], energy storage materials [5] and battery electrodes [6]. &nbsp;Batteries are the most suitable preference for electrical energy storage, which permits the energy storage and release flexibly on demand to sustain daily activities. The extreme benefit of composite materials in batteries is flexibility, strength and stiffness.&nbsp; rGO-based composites in general possesses various applications among them it contains specific applications exclusively for batteries. By N doping, graphene discloses exceptional performance as LIB anodes.&nbsp;&nbsp; Incorporation of nitrogen with graphene forms three types of structures, namely graphitic, pyridinic, and pyrrolic structure. According to density functional theory (DFT), the graphitic structure illustrates n-type semiconductor and the left over two unveil p-type semiconductor [7]. rGO is an attractive low dimensional especially, 2D-dimensional carbon material owing to its intrinsic properties superior electronic conductivity, high theoretical surface area (2600 m<sup>2 </sup>g<sup>-1</sup>), high surface-to-volume ratio and remarkable chemical stability. Consequently, these outstanding properties, graphene plays a significant role in fabricating composites. During the past decades, transition metal-based electrocatalysts with metal–nitrogen–carbon (M–N–C, M = Fe, Co, Cu, Ni) were evidenced as capable and cost-effective non-noble electrocatalysts to promote the ORR and OER with a high electroactivity and good stability, and were intensively investigated [8]. One of the favorable applications of the rGO nanocomposites is used as anode material in batteries.</p> <p>Graphene decorated with various nanoparticles based nanocomposites are good candidates for membranes, electrochemistry and batteries. Here, a facile eco-friendly chemical and thermal reduction route was utilized to synthesis of a new nanocomposites by Gd aggregates anchored on reduced graphene oxide (rGO) is reported. Gadolinium nitrate is highly conductivity, enriched surface area, active edges, and thermal stability, added to rGO to make rGO-GdN composite. Binary composite composed of gadolinium nitrate crystalline aggregates (GdN) and reduced graphene oxide (rGO) based on Modified Hummers Method were synthesized followed by chemical and thermal reduction process. During the synthesis, graphene oxide (GO) was reduced to rGO by using H<sub>2</sub>N.NH<sub>2</sub>.H<sub>2</sub>O and uniformly decorated by GdN. Gd incorporation in rGO matrix enhanced to form composite. The electrodes made of rGO-GdN&nbsp;nanocomposite synthesized by hydrazine hydrate as reduction aid showed a high. The best electrochemical performance of hydrazine hydrate reducing in rGO-GdN&nbsp;nanocomposite is basically attributed to the effect of Gd&nbsp;nanoparticles in preventing the restacking of rGO sheets. The results revealed that GdN particles squeezed on the surface of the graphene Nano sheets. The composition and morphological formation were characterized by using XRD, FTIR, Raman, AFM, SEM and HRTEM analyses. From X-ray diffraction (XRD), rGO-GdN composite was Nano crystalline structure. samples were investigated by powder XRD which is used to analyze crystal structure, lattice parameters and inter planar spacing. The inter planar spacing (<em>d</em>) is calculated by Bragg’s law. For rGO-GdN at 22.6<sup>o</sup> having (201) plane having <em>d</em>- spacing 3.88 A<sup>o</sup>. The average crystallite size of the rGO/GdN was calculated from XRD by using Scherrer equation found to be 0.43 nm and lattice strain was 0.39. Later, from Fourier Transform Infrared spectroscopy (FTIR) lead to attached with different functional groups. FTIR spectra shown oxygen containing functional groups with vibrational bands of hydroxyl (OH), carbonyl (C-O), ketone (C=C), epoxy (O-C-O) group and amine (C=N) groups. Raman analysis appearance of small peaks <em>D</em>, <em>G</em> and 2<em>D </em>bands at 1325, 1572 and 2660 cm<sup>-1 </sup>respectively. The ratio of <em>I<sub>D</sub>/I<sub>G</sub></em> and <em>I<sub>2D</sub>/I<sub>G</sub></em> were calculated as 0.84 and 0.17. these ratios proved rGO-GdN has multi layered structure. SEM, HR-TEM results indicated that GdN with particles are well anchored on graphene sheets. Moreover, AFM studies for thickness of rGO/GdN was estimated as thickness 72 nm with average Roughness and Root Mean Square are 24.56 and 40.45 nm respectively. The advantage of nitrogen and magnetic moments of gadolinium makes rGO/GdN as a prospective composite for battery electrode applications.&nbsp; </p> Ravi Nirlakalla, Surekha Gajula Copyright (c) 2021 Ravi Nirlakalla, Surekha Gajula https://spast.org/techrep/article/view/1751 Sat, 09 Oct 2021 00:00:00 +0000 Facile synthesis of high aspect ratio gold coated magnetic nanowires https://spast.org/techrep/article/view/724 <p>Magnetic nanoparticles are of immense importance in various biological applications such as<br>bio-imaging techniques, drug delivery, hematologic disease detection, biomolecules separation<br>(Figure 1). However, one of the limitations faced while using magnetic nanoparticles is to<br>synthesize small size, high surface to volume ratio particles via simple approach. Magnetic<br>nanoparticles in general are synthesized using hydrothermal method, template based method<br>or electrochemical methods. These conventional synthesis approaches are not only complex to<br>carry out but are also time consuming. Herein, we report a wet chemical method to synthesize<br>high aspect ratio magnetite (Fe3O4) nanowires. The benefit of this method is facile, rapid and<br>cost-effective process. The method involves a chemical reduction of ferrous sulphate and ferric<br>chloride. The resultant product was obtained in two portions – the precipitate and the<br>supernatant. Physical appearance of both the precipitate and supernatant was observed as<br>brown in colour. These synthesized magnetic nanoparticles in supernatant were light in weight<br>and completely dispersible in water for more than 6h. Surface morphology analysis of these<br>nanoparticles demonstrated that the precipitate was aggregate of nanoparticles whereas the<br>particles present in the supernatant were observed to be thin nanowires of dimension<br>approximately ranged from 200 to 275nm with calculated aspect ratio of approximately eleven<br>(Figure 2). Magnetic property was observed in these nanowires using a simple bar magnet.<br>Further, to enhance its biocompatibility, a thin gold coating was carried out on its surface. A<br>reaction was performed by citrate capping followed by reduction using sodium borohydride in<br>presence of chloroauric acid[1]. Gold coating was confirmed by a UV-vis absorbance spectrum<br>that showed a distinct plasmonic peak at 540 nm (Figure 3). The prospective application<br>planned in this study is for efficient separation of exosomes from bodily fluids. Conventionally<br>exosome isolation is challenging in terms of process complexity, cost and accuracy[2]. Gold<br>coated magnetic nanowires will allow direct attachment of a large number of exosomes by<br>affinity interactions which can significantly enhance the capture efficiency. The magnetic<br>activity allows magnetic nanowire based mixing, separation and purification via magnetic<br>isolation and purification steps[3]. Alongside the light weight and dispersible nature of these<br>nanowires prevents their agglomeration in the cell suspension allowing easy separation after<br>exosome attachment using the external magnetic field. Overall these as synthesized high aspect<br>ratio magnetic nanowires can be used as highly efficient nanocarriers for direct isolation of<br>bulk exosomes from bodily fluids via magnetic separation method and thus can avoid the use<br>of expensive commercial kit based multi-step pre-extraction procedures.</p> Pankhi Singh Copyright (c) 2021 Pankhi Singh https://spast.org/techrep/article/view/724 Wed, 15 Sep 2021 00:00:00 +0000 Effective of Tensile Strain on Thermal Transport of BaTe https://spast.org/techrep/article/view/2582 <p class="western" align="justify"><span style="font-family: Arial, serif;">Low lattice thermal conductivity (k</span><sub><span style="font-family: Arial, serif;">L</span></sub><span style="font-family: Arial, serif;">) materials are critically important as they find potential applications in thermal energy management applications such as thermoelectrics </span><span style="font-family: Arial, serif;">[1]</span><span style="font-family: Arial, serif;">, thermal insulation and thermal barrier coatings. In the present work, we have investigated the lattice dynamics and thermal transport in simple binary, BaTe. </span><span style="color: #000000;"><span style="font-family: Arial, serif;">The stability of BaTe at room temperature is established from the computed phonon dispersion curves and </span></span><span style="font-family: Arial, serif;">the lattice thermal conductivity for BaTe is found to be 9.84 and 3.92 W/m-K at 300 and 800 K, respectively</span><span style="color: #000000;"><span style="font-family: Arial, serif;">. We also studied the effect of tensile strain on </span></span><span style="font-family: Arial, serif;">k</span><sub><span style="font-family: Arial, serif;">L</span></sub><span style="color: #000000;"><span style="font-family: Arial, serif;"> and found that further reduction of </span></span><span style="font-family: Arial, serif;">k</span><sub><span style="font-family: Arial, serif;">L </span></sub><span style="font-family: Arial, serif;">is observed with strain due to softening of the lattice. </span><span style="color: #000000;"><span style="font-family: Arial, serif;">The low </span></span><span style="font-family: Arial, serif;">k</span><sub><span style="font-family: Arial, serif;">L</span></sub><span style="color: #000000;"><span style="font-family: Arial, serif;"> of BaTe is attributed to the short phonon life times and high scattering rates. The present study provides insights to achieve (ultra)low </span></span><span style="font-family: Arial, serif;">k</span><sub><span style="font-family: Arial, serif;">L</span></sub><span style="color: #000000;"><span style="font-family: Arial, serif;"> in simple crystal systems, which is essential for the development of energy conversion devices</span></span></p> S Chand Rakesh Roshan, Yedukondalu, T Venkatappa Rao, R Rakesh Kumar Copyright (c) 2021 S Chand Rakesh Roshan, Yedukondalu, T Venkatappa Rao, R Rakesh Kumar https://spast.org/techrep/article/view/2582 Sun, 17 Oct 2021 00:00:00 +0000 Growth, structural and electrical properties of spin coated LaNiO3 conducting oxide https://spast.org/techrep/article/view/1942 <p>Homogenous growth, structural and electrical properties of LaNiO<sub>3</sub> (LNO) perovskite thin film nanostructures using spin coating technique on quartz substrate has been studied. LNO has been widely used as a conducting bottom electrode for many perovskite oxide based device, such as, ferroelectric memory and micro sensor devices [1]. The advantages of perovskite materials over the simple Pt-based metal bottom electrodes are that, it has improved polarization fatigue, low leakage currents, aging characteristics and crystallographic compatibility with oxides based ferroelectric and recently reported perovskite resistive random-access memory (RRAM) materials [2,3]. Furthermore, oxide based bottom electrodes offers improved non-volatile memory characteristics such as endurance, low voltage consumption, retention cycle [4] etc. Sol gel spin coating technique was used due to its low cost with no requirement of high vacuum chamber, precision and control in the material composition. Commonly, perovskite LNO has been synthesised using organic solvents such as 2-mithoxyethanol with ethanolamine [5,6], acetic acid with deionized water [7] etc. However, LNO synthesized at higher annealing temperatures helps in attaining phase purity and these solvents showcases limitations such as porous film morphology, large pinhole density, higher surface roughness, etc. [1]. Hence, a modified method is employed in chemical deposition process for growth of LNO on quartz substrates. Poly-vinyl alcohol (PVA) being water soluble has excellent adhesion and thus, PVA has been used in the synthesis process. It also helps in the formation of uniform surface films along with the reduction of cracking density while drying [8]. Furthermore, PVA decomposes at 250 and hence there’s no possibility of any remnants left in the final product, as the samples have been annealed at a much higher temperature. The nanostructured growth of LaNiO<sub>3</sub> studied using X-ray diffraction confirmed its standard structural property of phase pure cubic perovskite symmetry. Surface morphological measurements were carried out at different spots to understand the uniformity of the sample, along with monodispersed grain distribution by using atomic force microscope (AFM). The RMS roughness of LNO was found to be 7.08 nm as shown in table 1, which incorporates that it can act as an excellent conducting bottom electrode providing brilliant seeding or buffer layer with enhanced nucleation sites [9]. This low surface roughness is an essential quality for the device formation as it influences smooth and crack free texture for the interface between the active layer and the electrode [1]. The presence of poly-vinyl alcohol used as stabilizing agent in the precursor solution may have influenced in the homogenous, smooth and crack free surface morphology of the film. As shown in fig.1, <em>I-V </em>characteristics of LNO demonstrates a small shift in current with the application of low perpendicular magnetic field of 0.58T. Voltage bias in the sequence of 0V → +Vmax → 0V → -Vmax → 0V was applied for the range of -5Vmax to +5Vmax. The variation in the resistance with the application of external magnetic field gives rise to magnetoresistance (MR) in the sample, which was found to be 48.26%. Henceforth, LNO may assist in forming the succeeding ferroelectric or ferromagnetic multilayer cascade, to enhance the <em>I-V </em>curve and further form a device heterostructure. &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</p> Nisha Thankachen, Poornima Sengunthar, Shivangi Patel, Utpal Joshi Copyright (c) 2021 Nisha Thankachen, Poornima Sengunthar, Shivangi Patel, Utpal Joshi https://spast.org/techrep/article/view/1942 Fri, 08 Oct 2021 00:00:00 +0000 Polymer bioconjugates as advanced drug delivery system in dental pulp regenerative therapy https://spast.org/techrep/article/view/2131 <p>Over the last few decades, various biologic medicines utilised in dentistry clinical practise has risen dramatically. Developments in the utilisation of proteins as healing agents have ushered in a slew of new benefits, including selective and definite action, low toxicity, and the ability to cure illnesses linked to genetic abnormalities(1). On the other side biologics are difficult to develop and manufacture, and they present a number of problems in terms of stability, formulation, delivery method, appropriate final dose form, and immunogenicity. These difficulties are connected to proteins' a complex structure, which is the primary source of their physical instability, as well as amino acid chemical breakdown profiles. Protein-polymer conjugation is described as a combination of peptide/protein segments with constant chain lengths and predefined monomer sequences with a predetermined number of synthetic polymer chains(2). Finding a balance between numerous Polymer factors is thus required when formulating a stable protein, and each protein's stable formulation is created in its own unique method. The notion that proteins are delicate molecules whose integrity might be jeopardised by chemical changes was a logical premise that worked against efforts to conjugate proteins to polymers for distribution. It's worth remembering, though, that by attaching chemical groups to proteins, nature has supplied the tools for post-translational changes to change their activity, stability, and pharmacokinetics. Various scholars have initiated work to modify proteins with the help of polymers. This research unlocked the way for polymers proteins conjugation, a method that has enhanced the efficacy of biologics by incapacitating key flaws including instability, short half-lives, and immunogenicity, that have hampered their clinical practise usage(3).</p> <p>Despite the potential of these bioconjugates for drug administration, protein polymer conjugates pose difficulties. Protein’s pleat and gather into particular three-dimensional structures. The shape and orientation of the enzyme active site, which is a direct result of the specific folding configuration, is important for proper protein activity. Typical polymer synthesis reaction conditions, on the other hand, might be severe and damage a protein's structure, resulting in decreased enzymatic activity(4). Biodegradable polymers are a key component of these materials, particularly for bone regeneration and periodontal surgery. Some naturally occurring polymers have proved to be useful in the design of Drug delivery system because of their excellent biocompatibility, biodegradability and low cost. The use of this family of polymers has some drawbacks, namely the strong immunogenic response, possibility of disease transmission, non-uniformity in properties from batch-to-batch and difficulties in their purification(5). Only a few biodegradable polymers, however, have been tested in therapeutic settings. Up until tissue repair and regeneration, biodegradable materials would be developed to encourage cell proliferation and differentiation. They should then be excreted from the body to avoid long-standing foreign compound storage via parenteral administration. Many synthetic materials consisting of metals, ceramics, and polymers satisfy these criteria, making them potentially useful for periodontal or bone regeneration. Polyglycolide, poly-(lactide-co-glycolide) acids and polycaprolactone are among these polymers, which were first developed for suture applications in the 1960s. These polymers degrade due to water penetration into their structure, which results in polymer hydrolysis and, in certain cases, local reactions due to hazardous acid release. Many studies have recently focused on the use of proteins in conjunction with various biodegradable polymers or composites as a technique for dental tissue engineering. Although the list of biomaterials offered is extensive use, some of the findings are worth discussing.</p> <p><strong>&nbsp;</strong></p> Manasa B L Copyright (c) 2021 Manasa B L https://spast.org/techrep/article/view/2131 Fri, 08 Oct 2021 00:00:00 +0000 Preparation of CuS thin films by SELD technique for applications as absorber layer in solar cell structure https://spast.org/techrep/article/view/2289 <p>The last few decades transition metal chalcogenides have been widely studied due to their excellent physical and chemical properties. Among them, copper sulphide environmentally friendly and low cost semiconductor is an important p type material which has great interest due to their importance in basic scientific research and potential application for solid state solar cells[1], electro conductive coatings, lithium ion batteries, electrodes and chemical sensor [2-3]. As it is made up of earth abundant elements of copper and sulphur, the efficient use of these materials can be useful in replacing many toxic and expensive semiconductors. The challenging task in this work is to deposit uniform sulphur film on the copper is very difficult and controlling sulphur rate during deposition is another challenges. One of the major problems encountered is wide difference in the deposition parameters of Cu and S, which results in a non-uniform composition and also show some secondary phases. The new thing in present case in this work is raw copper and sulphur element evaporates to form CuS compound on annealing by stacked elemental layer deposition (MSELD) technique. The CuS films were obtained on annealing of 200 nm and 600 nm on Cu/S stacks deposited on corning glass substrate. The multi stacked elemental layer deposition (MSELD) technique was used for the deposition of the films of Cu and S layers. Thermal evaporation of Cu and S elements was performed under vacuum pressure&nbsp;&nbsp; ̴ 2X 10<sup>6</sup> mbar in a vacuum coating unit (VCU) at room temperature. Annealing of the samples was carried out at a base vacuum pressure &nbsp;&nbsp;̴ 1 x 10<sup>3</sup> mbar in a tubular furnace. The affect of annealing temperature and film thickness on structural, optical transport phenomena, morphology and composition of as-deposited and annealed films have been studied. The structural properties of films were characterized by X-ray diffraction XRD and optical by UV-Viz spectrophotometer. The structural properties were analysed using X-ray diffractometer data collected in the 2θ range 10<sup>0</sup>-70<sup>0</sup>. The XRD results indicate as deposited and annealed films show polycrystalline nature. It is observed that obtained films present dominating CuS phase along with minor phase of sulphur. As the annealing temperature changing from 373 K to 473 K the intensity of CuS peak improved. On further increase in annealing temperature 523 K and above CuS phase is completely change to Cu<sub>2</sub>S phase in both thickness. However at 473 K film thickness 600 nm is better than lower thickness in term of improvement in intensity, decrease in FWHM and enhancement in crystallite size. The crystallite size increase from 7 nm- 18.5 nm &nbsp;that from XRD analysis and the CuS thin films have tetragonal structural with preferred orientation along (103) plane. The evolution of phase is confirmed by XRD result which is well corroborated by optical result also. The optical properties have been studied in the range of wavelength 300- 800 nm. Optical constants such as band gap, refractive index, extinction coefficient and were determined from UV-Visible absorption spectrum. The transmittance value is decrease with increase in film thickness and optical study provided good absorption in the visible region. The band gap of the films was calculated from transmittance&nbsp;data bandgap energy was decreased and found close to optimum values (2.24 -2.00 eV) with increases in films thickness and absorption coefficient(α) of the films in both thickness was found to be &gt;10<sup>4</sup>cm<sup>-1 </sup>for all annealing temperature.</p> NARESH PADHA Copyright (c) 2021 NARESH PADHA https://spast.org/techrep/article/view/2289 Thu, 07 Oct 2021 00:00:00 +0000 Study of structural, electronic and thermoelectric properties of ZrP2 monolayer https://spast.org/techrep/article/view/1245 <p>The industrial demand for energy is increasing at a very high rate with the advancement in technology. To fulfill this demand, fossil fuels and non-renewable resources are used. The over utilization or massive consumption of natural resources led to the deficiency of these resources for the future generations. An enormous amount of energy is wasted in the form of heat and poisonous gases which have very hazardous effects on the surroundings [1]. Thermoelectricity is the best phenomena in which there is a direct conversion of heat into electricity [2]. The efficiency of thermoelectric material is denoted by a dimensionless figure of merit (ZT) parameter which depends on the Seebeck coefficient (S), electrical conductivity ( σ ) and thermal conductivity of the materials [3]. The materials having high values of Seebeck coefficient, electrical conductivity and low thermal conductivity are considered as good thermoelectric materials.<br>After the discovery of graphene in 2004 [4], the large number of two dimensional (2D) materials such as transition metal dichalcogenide (TMDC) monolayers like MoS<sub>2</sub> , MoSe<sub>2</sub> etc., group III and IV monochalcogenides like SnSe, GaS, GeSe, phosphorene arsenene etc. have been investigated theoretically and synthesised experimentally [5-7]. These materials are widely used in the fabrication of thermoelectric devices. Recently, the various investigations proposed that the HfN<sub>2</sub> monolayer is dynamically, thermally and mechanically stable. It has been shown that HfN<sub>2</sub> monolayer is a suitable candidate for the fabrication of memory devices, thermoelectric devices and photocatalysts etc. [8-10]. Yang et al. theoretically investigated the thermoelectric performance of XP 3 (X= Al, Ga and In) monolayers and found that these monolayers have superior value of ZT parameter [11]. Somaiya et al. investigated that hexagonal SiX (X= N, P, As, Sb and Bi) monolayers are suitable materials for low temperature thermoelectric devices [12]. The ZrBrCl monolayer is found to be dynamically, mechanically stable and can be used as a photocatalyst in water splitting application [13]. Xinyu Liu and co authors investigated the thermoelectric performance of MNBr &nbsp;&nbsp; (M = Zr, Hf) monolayers and found that these monolayers have interesting thermoelectric properties [14].<br>Motivated by these recent investigations, we study the structural, electronic and thermoelectric properties of ZrP<sub>2</sub> monolayer. We perform Density functional theory based first principles calculation with the use of Quantum Espresso simulation package. The ZrP<sub>2 </sub>monolayer consists of three atomic layers, in which Zr atom is sandwiched in the layers of P atoms. It has hexagonal lattice structure having lattice constant 3.04 Angstrom. The Thermo_pw package is used for calculating elastic constants . It has only two independent elastic constants C<sub>11</sub> = C<sub>22</sub> and C<sub>12</sub> which satisfies the Born criteria of mechanical stability i.e.<br>C<sub>11</sub> , C<sub>66</sub> = (C<sub>11</sub> − C<sub>12</sub> ) ∕ 2 &gt; 0. The calculated value of cohesive energy shows that this monolayer is energetically stable. The absence of imaginary curves in the phonon dispersion shows that ZrP<sub>2</sub> monolayer is dynamically stable. The calculated lattice constant, bond length , elastic constants and cohesive energy are shown in table 1. The electronic band structure, density of states (DOS) and projected density of states (PDOS) are shown in fig. 1. The electronic band structure shows that ZrP<sub>2</sub> is a direct band gap semiconductor having magnitude of 0.78 eV. From the PDOS profile, we found that the ‘d’ orbital of the Zr atom and ‘p’ orbital of the P atom mainly contributes in the formation of conduction and valence bands. The electronic transport coefficients are calculated using Boltztrap code. The evaluated electrical conductivity and electronic thermal conductivity depends on the relaxation time of charge carriers (i.e. electrons and holes). We calculate the relaxation time of charge carriers by using Deformation potential theory. The lattice thermal conductivity is calculated by solving Slack's equation. The ZT parameter is obtained by using the above evaluated values for both n-type and p-type ZrP 2 monolayer. The variation of ZT w.r.t. carrier concentration for n-type and p-type monolayer is shown in fig. 2. The maximised values of obtained ZT parameters are shown in table 2. From the evaluated results, we conclude that ZrP<sub>2</sub> monolayer is a suitable candidate to be used in the manufacturing of thermoelectric devices.</p> Gurpal Singh Khosa, Shuchi Gupta, Ranjan Kumar Copyright (c) 2021 Gurpal Singh Khosa, Shuchi Gupta, Ranjan Kumar https://spast.org/techrep/article/view/1245 Thu, 30 Sep 2021 00:00:00 +0000 Design of Ionic liquid functionalized chitosan with optimized hydrophilic/hydrophobic structural balance as catalyst for CO2 fixation https://spast.org/techrep/article/view/613 <p>“Recycling CO<sub>2</sub> with chitosan”. An increase in the anthropogenic carbon dioxide level in the earth’s atmosphere over the last few centuries is the primary reason for global warming. The increasing growth of population and associated urbanization demand a continuous supply of energy for day-to-day activities making it quite challenge to reduce CO<sub>2 </sub>concentration in the atmosphere. The use of CO<sub>2</sub> as a C1 carbon source to synthesize value-added chemicals is one of the sustainable approach to reduce the CO<sub>2</sub> level from the atmosphere. However, the reactions involving CO<sub>2</sub> are highly energy-intensive because of its chemical inertness and extremely high C=O bond energy of 806 kJ/mol [1]. Therefore, activation of CO<sub>2</sub> at mild conditions is a determining factor in CO<sub>2</sub> utilization reaction. Among various CO<sub>2</sub> utilization processes, the atom economic and non-redox CO<sub>2</sub> fixation into epoxides to synthesize cyclic carbonates is a promising scheme that can be applied on an industrial scale at ambient conditions. The resulting product cyclic carbonates have potential applications in industries such as solvent in a lithium-ion battery, fuel additive, polar aprotic high boiling solvent, precursor for polycarbonate and polyurethanes, intermediates in the drug industry, and many more [2]. Among different catalysts, biopolymers based catalytic systems are of particular interest because they fall under green chemistry criteria due to their biocompatible, biodegradable and non-toxic in nature. Chitosan (CS) is the second most abundant natural polymer after cellulose and has attracted huge research attention owing to its easy structural tunability due to the presence of several hydroxyl and amine groups [3]. Examples of chitosan-based catalytic systems for epoxide to cyclic carbonate conversion include quaternary phosphonium IL grafted chitosan [4], imidazolium IL grafted chitosan [5], dicationic IL grafted chitosan [6], carboxylic acid and quaternary ammonium moieties functionalized chitosan [7], zeolite-chitosan composite/TBAI [8], metal-organic hybrid (MOH) [9]<em> etc</em>. However, most of the above reported catalysts required extreme reaction conditions like high pressure and high temperature. It is also found that smaller epoxides like epichlorohydrin gets converted to respective cyclic carbonate easily at 1 atm CO<sub>2</sub> pressure whereas large and non-polar epoxide like tert butyl glycidyl ether requires higher CO<sub>2</sub> (30 atm) pressure for the reaction to occur [9]. Our objective is to develop metal free chitosan-based catalyst that can perform solvent-free, CO<sub>2</sub> cycloaddition reaction with epoxide at atmospheric pressure and in the absence of any co-catalyst.</p> <p>&nbsp;We have synthesized series of ionic liquid grafted chitosan catalysts with range of hydrophobicity by changing the ionic liquid and hydrocarbon chain part. Catalyst with pyridinium IL and octyl group attached to it displayed best catalytic activity for various epoxide. The resulting good activity is expected due to the better attractive interaction between epoxides side chain and long carbon chain attached to the catalyst. Furthermore, on the basis of comparison study and wettability study a molecular interaction between substrate and active site of the catalyst is proposed which helps to understand the selectivity of the different catalysts towards various epoxides. Additionally, throughout this study no harmful chemicals were utilised and all the catalysis reactions were performed in solvent-free medium. ­­This study provide a new insight in catalyst designing methodology to tune its hydrophobic/hydrophilic structural balance on the basis of expected molecular interaction during reactants activation step.</p> khushboo paliwal, Tanmoy Biswas, Antarip Mitra, Gouri Tudu, Venkataramanan Mahalingam Copyright (c) 2021 khushboo paliwal, Tanmoy Biswas, Antarip Mitra, Gouri Tudu, Venkataramanan Mahalingam https://spast.org/techrep/article/view/613 Thu, 16 Sep 2021 00:00:00 +0000 Recent advances in template assisted growth engineering of inorganic nanocrystals https://spast.org/techrep/article/view/1766 <p>Nanoparticles (NPs) of controlled size, shape, and composition have attracted significant attention due to their applicability in future generation device. The interaction of particles with interfaces varies with the change in their morphology. The anisotropic nanostructures are of considerable attention for scientific and technological application as they are expected to exhibit substantial advantages over their isotropic counterparts in several fields such as enhanced energy harvesting, improved charge transport properties, nonlinear optical responses, enhanced optical gain and polarized light absorption and emission [1-2]. Nanocrystals can be synthesized by two different strategies: the “top-down” approach, which employs physical methods, and the “bottom-up” approach, which applies solution-phase colloidal chemistry. Utilizing the top-down approach, a vast quantity of nanocrystals can be produced, however, controlling of size and shape of nanocrystals through this “top-down” approach is difficult. On the contrary, “bottom-up” approach allows the utilization of colloidal chemical methods to synthesize size and shape tuned nanocrystals with the help of chemical nucleation and growth process in bulk solution. It is noteworthy to mention that the crystallization from a solution governs the growth process which subsequently determines the shape of the particle [3]. The anisotropic growth of nanomaterials is majorly controlled by their crystallographic structure, surface free energy as well as impact of using various templates such as surfactants. &nbsp;Classically, atom-by-atom or monomer-by-monomer addition to an inorganic or organic template or by dissolution of unstable phases and re-precipitation of the more stable phase are responsible for crystal growth. A clear understanding of the methodology and parameters controlling the precipitation helps in the growth engineering of size and shape modulated nanoparticles. Several competing factors, such as preferential attachment to different crystal facets, surfactant-mediated directional growth, and the utilization of surface coordinating ligands induce the morphologies of anisotropic particles. A number of fascinating anisotropic nanostructures including nanorods [4], wires [5], tetrapods [6], multipods [7], dumbbells [8] and platelets [9] have been synthesized employing solution chemistry. However, still there is a quest of low cost and easily scalable synthesis strategies to systematically develop size and shape modulated nanoparticles. &nbsp;&nbsp;</p> <p>In this review, the state-of-the-art in the area of the synthesis techniques for the exploration of size and shape control of a variety of inorganic nanomaterials is overviewed. The crystal growth mechanisms both intrinsically and in the presence of templates are discussed.&nbsp; Finally, we conclude with the recent development in the research progress in this topic as well as our perspectives on the challenges and opportunities.</p> Dr Sudeshna Ray Copyright (c) 2021 Dr Sudeshna Ray https://spast.org/techrep/article/view/1766 Sat, 09 Oct 2021 00:00:00 +0000 A Review on Utilization of Secondary Construction Material https://spast.org/techrep/article/view/80 <p>The secondary construction materials market has been around for a long time. However, it has largely been ad-hoc. Considering the supply chain, consistent raw material supply cannot be guaranteed, which can be attributed to poor C&amp;D waste management practice. If the infrastructure was sufficient, there would be a problem with the distribution of secondary materials and products due to a lack of sufficient demand, which is a primary cause of many recycling failures. In short, the secondary construction materials market is currently not selfsustaining. By virtue of its nature, the secondary construction materials market has not been able to explore or demonstrate its full potential. According to studies, around 20-30% of the material generated in tile production factories ends up as trash. Ceramic tile trash is generated not only during the destruction of constructions, but also in the production process of ceramic tiles. To cope with the limited supply of natural aggregate and decrease building waste, this waste material can be reused. As a substitute for coarse and fine aggregates, crushed waste ceramic tiles and crushed waste ceramic tile powder are utilised. The ceramic waste crushed tiles were partially substituted in place of coarse aggregates, fine aggregates and binder by 10%, 20%, 25%, 30%, 40%, 50% and 100%. It has been discovered that replacing aggregates with ceramic aggregate enhances the strength of concrete blocks by up to 50% for fine aggregate replacement, by up to 40% for coarse aggregates replacement, and by up to 30% for replacing the binder. The world is experiencing population growth, rapid urbanization, and industrial output expansion. These developments have resulted in a multifaceted increase in demand for natural resources, in particular for materials. There is growing concern about the depletion of resources, harm to the environment and climate change. Large CO2 emissions are involved in the manufacture of building materials such as cement, bricks and mortars, and their disposal often affects the environment, it is essential to minimize the environmental footprint of these materials as much as possible. If solid wastes, like demolished concrete and red clay ceramics, can be converted into useful products by exploiting their chemical reactivity, it would increase resource efficiency and reduce environmental damage[1]. Construction is not an environmentally friendly activity. The materials employed provoke an intense demand for natural resources, which has given rise to enormous environmental pressure. Among those, the so-called clay-based materials are one of the most used (facades, roofs, partitions, floors, etc.). Albeit, ceramics are based on some of the most abundant raw materials in the Earth’s crust, the pressure of their manufacture has begun to take its toll on our surroundings[2]. In recent days construction and demolition waste represents a large amount of residues, among which the ceramic materials (mainly, bricks and tiles) are an important part as, in many countries [3]. The main objective of this work is to develop low cost and sustainable alternate building products like bricks. The research conducted on the use of ceramic as a substitute for fine aggregate, coarse aggregate and cement can be utilized for the production of concrete blocks especially where low-cost housing is concerned and leading to more ecofriendly building products.</p> Nandan Gowda T, Anand Kumar B G Copyright (c) 2021 Nandan Gowda T, Anand Kumar B G https://spast.org/techrep/article/view/80 Sat, 07 Aug 2021 00:00:00 +0000 Quantum chemical studies on the copper corrosion inhibition efficiency of benzenethiol derivatives https://spast.org/techrep/article/view/2447 <p>The corrosion inhibition activities of series of benzenethiol (BT) derivatives were studied by DFT based electronic structure calculations. The effect of electron donating (i.e., -CH<sub>3</sub>, -CHCH<sub>2</sub>, -CH<sub>2</sub>CH<sub>3</sub> -OCH<sub>3</sub>, -NH<sub>2</sub>, -NHCH<sub>3</sub>, NCH<sub>3</sub>CH<sub>3, </sub>NHCOCH<sub>3 </sub>and -COOCH<sub>3</sub>) and electron withdrawing functional groups (i.e., -F, -Br, -NO<sub>2</sub>, -COOH, -CONH<sub>2</sub>, -COCH<sub>3 </sub>and -CHO) in BT derivatives were incorporated to understand the corrosion inhibition activity of the molecules. These functional groups significantly affect the corrosion resistance of the material. It is found from our calculation that, the electron donating derivative of NH<sub>2</sub>-BT act as better corrosion inhibiting ability when compared to other selected molecules. In most cases it was found that a substitution on the benzene ring of BT directly influences the corrosion inhibiting property. The efficiency of inhibition depends greatly on the structure and position of the substituents on BT. The nature of the substituent functional groups affects the extent of bonding between the inhibitor and the copper (Cu) surface. The local reactivity descriptors (Fukui functions), molecular electrostatic potential (MEP) and frontier molecular orbitals (FMO) analysis can provide valuable information to identify the suitable inhibitor molecules for better corrosion resistance of Cu surface.</p> RAJAPANDIAN VARATHARAJ Copyright (c) 2021 RAJAPANDIAN VARATHARAJ https://spast.org/techrep/article/view/2447 Tue, 12 Oct 2021 00:00:00 +0000 Synthesis and characterization of V2O5 supported on TiO2 selective catalytic reduction (SCR) catalyst for De-NOX https://spast.org/techrep/article/view/126 <p>The most efficient after-treatment technology for reducing harmful NO<sub>x</sub> emissions from mobile and stationary sources of Power plants is the selective catalytic reduction (SCR) of NO<sub>x</sub> with ammonia (NH<sub>3</sub>). V<sub>2</sub>O<sub>5</sub>-WO<sub>3</sub>based SCR catalysts reduce NO<sub>x</sub> selectively between ca. 200 and 500°C. Pure and (NH<sub>4</sub>VO<sub>3</sub>:WO<sub>3</sub>:TiO<sub>2</sub>) vanadium (V<sup>5+</sup>) and WO<sub>3</sub> doped TiO<sub>2 </sub>have been synthesized by Sol-gel method, using different sources of carrier materials. Synthesized materials have been characterized by Brunauer-Emmett-Teller (BET) and De-NO<sub>x </sub>techniques. Specific surface area and the mean pore diameter of the catalysts were determined by BET. BET study shows the catalyst prepared by TiO<sub>2</sub>/ V<sub>2</sub>O<sub>5</sub>-WO<sub>3 </sub>from titanium oxy sulphate with 87:10:03 ratio of TiO<sub>2</sub>:Tungsten:Vanadia has highest surface area of 150.32m<sup>2</sup>/g. Percentage of NO<sub>X</sub> conversion is found out by De-NOx test. Highest NO<sub>x</sub> conversion was observed for catalyst prepared by titanium, NO<sub>x</sub> conversion reduces with increase in calcination time and increases with decrease in space velocity. At 2000hr<sup>-1</sup> space velocity the catalyst synthesized from titanium oxysulphate with 85:10:05 ratio of TiO<sub>2</sub>:Tungsten:Vanadia gives highest NO<sub>x</sub> conversion of 36.74% at 440<sup>o</sup>C &amp; TiO<sub>2</sub> in 2-Propanol with 87:10:03 ratio of TiO<sub>2</sub>:Tungsten:Vanadia gives highest NO<sub>x </sub>conversion of 25.8% at 325<sup>o</sup>C.</p> Prakash Binnal Copyright (c) 2021 Prakash Binnal https://spast.org/techrep/article/view/126 Wed, 08 Sep 2021 00:00:00 +0000 Graphene and Germanane materials for energy applications-A review https://spast.org/techrep/article/view/440 <p>Research on 2D materials is a hot topic in academia and industry to explore novel materials like graphene and its analogues, silicene, germanane. Graphene's success has shown not only that it is possible to create stable, single-atom-thick sheets from a crystalline solid but that these materials have fundamentally different properties than the parent material. Graphene is a potential 2D material suitable for advanced applications especially when it is used in the form of graphane. This is because, graphane is found to have electronically stable compared to parent material due to van der Waals interactions. Germanane is a germanium graphane analogue, an advanced 2D material and it is better than graphene because, they do not form flat planar structure like as in graphene. Germanane can be a hydrogenated form of germanium network with hydrogen atoms are distributed equally above and below the Ge layer. Therefore, surface modification of Germanane is one of the hot topic of research. In this review, we elaborate on applications of graphene and germanane in sensing, supercapacitors and optoelectronic devices. Overall, this work demonstrates, electrochemical analysis of graphene for optoelectronic, supercapacitor and sensing applications. Light emitting diode (LED) can be prepared by stacking metallic graphene with various semiconducting monolayers. These, heterostructured material is expected to grow further on increasing the number of available 2D crystals and improving their electronic quality. Graphene-based nano-inks can be used to manufacture supercapacitors in the form of flexible and printable electronics. Another promising application of graphene will be in energy storage devices due to these novel properties like highly tunable surface area, outstanding electrical conductivity, good chemical stability and excellent mechanical behavior. Also, this paper summaries analysis of synthesis, structural modifications, thermal stability and enhanced optoelectronic properties of germanane in detail. A novel electrochemical sensor which had crucial properties such as being reproducible, repeatable, and stable was developed for phenol detection by using, the complex materials like methyl germanane and chemically activated pencil graphite electrodes. Germanane field effect transistors fabricated from multilayer single crystal flakes enhance the conductivity. Germanane, exhibits viable pathway towards the replacement of graphene applications [1].</p> Rohini, RAMACHANDRA NAIK, revathi Copyright (c) 2021 Rohini, RAMACHANDRA NAIK, revathi https://spast.org/techrep/article/view/440 Wed, 15 Sep 2021 00:00:00 +0000 SYNTHESIS AND CHARACTERIZATION OF FULLERENE (C60) DOPED CH3NH3PbI3 PEROVSKITE THIN FILMS: DFT CALCULATIONS https://spast.org/techrep/article/view/1153 <p>In this research work, pure and Fullerene (C<sub>60</sub>)-doped perovskite thin films were prepared on glass substrates by spin coating method with different concentrations of fullerene (C<sub>60</sub>). The structural, morphological, and optical characteristics of the as deposited thin films were analyzed using XRD, FE-SEM with EDAX and optical spectroscopic measurement respectively. &nbsp;The X-ray diffraction confirms that all deposited perovskite thin films have tetragonal structure and are highly oriented along the (110) plane.&nbsp; The pack morphology of the perovskite films was investigated by field emission scanning electron microscope (FE-SEM). The elemental composition of perovskite thin films was confirmed by energy-dispersive X-ray of analysis (EDAX). With the aid of Full Prof software (FPS), the Rietveld refinements for all XRD patterns were justified by taking up the tetragonal phase of all produced perovskite thin film samples. The addition of Fullerene (C<sub>60</sub>) resulted in increased gains and a more compact surface development of the perovskite thin film, with fewer flaws. The optical band gap of as deposited thin films of Fullerene (C<sub>60</sub>) doped CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub> perovskite thin films was studied using absorption spectroscopy. Geometrical properties, Electronic properties, and Optical properties were also studied by using the computational methodology. Optical properties have been experimentally and theoretically related by density functional theory (DFT). Optical properties have been calculated using density functional perturbation theory implemented in VASP. All of these films have direct band gap and band gap values are in the range of 1.58 eV -1.55 eV, allowing them to be utilized in solar cell applications.</p> VIRENDRA KUMAR BEER PAL SINGH Copyright (c) 2021 VIRENDRA KUMAR BEER PAL SINGH https://spast.org/techrep/article/view/1153 Thu, 23 Sep 2021 00:00:00 +0000 Synthesis of carbon-based ultrafine copper nanoparticles to promote nitrate electroreduction to produce ammonia https://spast.org/techrep/article/view/591 <p><strong>Abstract</strong>:</p> <p>Ammonia is an important industrial chemical used in the manufacture of fertilizers, nutrients, medicines and the future of high energy density solar fuel.[1] The global supply of ammonia is largely dependent on the Haber-Bosch process, which uses iron-based catalysts to catalyze the reaction of nitrogen and hydrogen at high temperatures and pressures. [2] However, as high energy inputs and high carbon dioxide emissions lead to global climate change, there is an urgent need to develop sustainable alternatives to the Haber-Bosch process. What's more, the increasing accumulation of nitrates in the environment has caused health problems for organisms. Early goals of wastewater denitrification focused on the conversion of nitrates and nitrites into unwanted nitrogen. [3] Nitrate electrochemical reduction (NO<sub>3</sub>RR) is becoming a promising method because of its fragility, low cost and high efficiency. [1, 4, 5]</p> <p>&nbsp;</p> <p>The different oxidation states of nitrogen add to the complexity of NO<sub>3</sub>RR. The reaction of NO<sub>3</sub>RR to ammonia involves multiple electron transfer processes, which requires that the electrocatalyst has good activity, selectivity and stability. [6, 7] In recent years, several strategies to improve NO<sub>3</sub>RR performance to achieve high ammonia yield have been studied, including surface engineering, [8,9] surface oxygen vacancy engineering, [10-12] bimetallic nanostructures, monatomic catalysts, etc. [6, 13] Few single catalysts can be optimized for all of these criteria. In order to achieve efficient electrolytic conversion of nitric acid or nitrite ions, catalysts are usually composed of multiple components, each of which can fully play its role. Among these active catalysts, nano-copper has high activity and selectivity to NO<sub>3</sub>RR and ammonia, and is a highly efficient catalyst with great potential. [4, 7] However, efficient copper-based catalysts have been challenged due to the lack of easy synthesis methods. Therefore, the development of a simple method for the preparation of nano-structured copper electrocatalyst has practical application significance for the production of ammonia by NO<sub>3</sub>RR.</p> <p>&nbsp;</p> <p>Unlike the metal-based electrocatalysts mentioned above, the metal-free carbon is also very efficient for NO<sub>3</sub>RR electrostatic ammonia production. [14-16] The advantage of carbon electrocatalysts lies not only in the enhancement of NO<sub>3</sub>RR activity, but also in the high inhibition of competitive hydrogen evolution reaction (HER). Apart from the well-known synthesis of graphene, carbon nanotubes and fullerenes, which can be achieved by specific methods, other nanostructured carbons are usually obtained under extreme conditions, such as hydrothermal and high-temperature pyrolysis. For example, various porous carbons are prepared by combining soft or hard template methods and pyrolysis at high temperatures in an inert atmosphere. [17-20]</p> <p>&nbsp;</p> <p>In order to solve the difficulty that NO<sub>3</sub>RR is easy to obtain nanostructured Cu and carbon electrocatalyst, a feasible synthesis method is needed. In this study, ultrafine copper nanoparticles with banded carbon nanostructure were prepared by one pot solution method. The prepared sample can effectively catalyze the formation of ammonia from NO<sub>3</sub>RR. At 0.4 vs. RHE (reversible hydrogen electrode), the ammonia yield is 220.79 μg h<sup>-1</sup> mg<sup>-1</sup>, and the Faraday efficiency can reach 62.3%. This study provides a new method for electrocatalytic nitrate conversion of carbon nanoparticles.</p> <p>&nbsp;</p> <p>&nbsp;</p> Zhe Wang Copyright (c) 2021 Zhe Wang https://spast.org/techrep/article/view/591 Sun, 19 Sep 2021 00:00:00 +0000 Hydroxyapatite-graphitic carbon nitride based composites: Synthesis, characterization and evaluation of bioactivity https://spast.org/techrep/article/view/2779 <p>Hydroxyapatite (HAP) has received considerable attention for biomedical application due to its sublime properties such as biocompatibility, bioactivity and non-toxicity. Graphitic carbon nitride (GCN) is biocompatible and exhibit antibacterial activity. It is used for fluorescent imaging and therapeutic applications [1-3]. It is believed that a combination of HAP and GCN as a composite material could widen the window of opportunity for biomedical application. In this perspective, the present study aims to synthesize hydroxyapatite/graphitic carbon nitride (HAP-GCN) and lithium doped hydroxyapatite/graphitic carbon nitride (Li-HAP/GCN) composites by in situ chemical precipitation method. The dopant (Li) ratio was chosen as 0.01 M, 0.05 M, 0.10 M and 0.50 M. The HAP/GCN and Li-HAP/GCN composites were characterized for their morphological and structural characteristics by scanning electron microscopy and X-ray diffraction measurement. Fourier transform infrared spectroscopy was used to identify the nature of functional groups while their chemical nature was ascertained by X-ray photoelectron spectroscopy. The <em>in vitro</em> bioactivity of the HAP/GCN and Li-HAP/GCN composites was determined by immersing them in simulated body fluid (SBF) at 37 ± 1 °C for 240 h. The FTIR spectra of pure HAP, HAP/GCN and Li-HAP/GCN composites are presented in&nbsp; fig. 1. The FT-IR spectrum of HAP reveals a band at 3572 cm<sup>-1</sup> which can be correlated to the stretching vibration of the hydroxyl group. The band at 1652 cm<sup>-1</sup> is due to H-O-H bending vibration of H<sub>2</sub>O. The peak at around 963 cm<sup>-1</sup> can be related to the non-degenerated n<sub>1</sub> symmetric stretching mode of the P-O bond of the phosphate group while the bands at 1030 and 1098 cm<sup>-1</sup> can be ascribed to the triply degenerated n<sub>3</sub> asymmetric stretching mode of P-O bond of the phosphate group. The IR bands at 565 and 603 cm<sup>-1</sup> correspond to the triply degenerated n<sub>4</sub> bending modes of O-P-O bond of the phosphate group. The presence of IR bands pertaining to the PO<sub>4</sub><sup>3-</sup> and -OH groups suggest the formation of HAP. The FT-IR spectrum of HAP/GCN composite reveals the presence of several bands pertaining to the PO<sub>4</sub><sup>3-</sup> group and those pertaining to GCN suggesting the successful formation of HAP/GCN composite. A comparison of the FT-IR spectra of pure HAP, GCN and HAP/GCN composite in the frequency range of 2000 to 400 cm-1 is shown in inset A of Fig. 1. It is evident that when compared to pure HAP, the intensity of the peaks pertaining to the phosphate group is considerably reduced for HAP/GCN composites, suggesting a decrease in crystalinity. The IR bands at 806 and 889 cm<sup>-1</sup> can be correlated to the tris-triazine units of the GCN and deformation mode of N-H bond, respectively. The bands located between 1100 and 1700 cm<sup>−1</sup> can be assigned for the typical stretching vibrations of C-N heterocycles. The IR bands at 1597, 1506, 1434 and 1364 cm<sup>-1</sup> can be assigned to the stretching vibrations of the heptazine unit of GCN. The broad band at &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;3300 cm<sup>−1</sup> can be related to the N-H stretching vibration. The study reveals that HAP/GCN and Li-HAP/GCN composites possessed abundant surface hydroxyl, phosphate and–NH<sub>2</sub>/–NH–/=N groups. Upon immersion in SBF, the HAP/GCN and Li-HAP/GCN composites degrade by a hydrolytic mechanism, promoting the formation of apatite on their surface [4]. The study concludes that the HAP/GCN and Li-HAP/GCN exhibit excellent bioactivity and can be explored for biomedical applications.</p> <p>&nbsp;</p> <p><img src="https://spast.org/public/site/images/ravistudent/fig.-1-vishwapriya.png" alt="" width="1231" height="1047"></p> <p><strong>References</strong></p> <p>[1] J. Zhang, Y. Kan, L. Gu, C. Wang, Y. Zhang, <em>Chemistry - An Asian Journal</em>, 16, 2003-2013, 2021.</p> <p><u>doi.org/10.1002/asia.202100499</u></p> <p>[2] G. Liao, F. He, Q. Li,, L. Zhong, R. Zhao, H. Che, H. Gao, B. Fang, <em>Progress in Materials Science</em> 112, 100666, 2020. <a href="https://doi.org/10.1016/j.pmatsci.2020.100666">https://doi.org/10.1016/j.pmatsci.2020.100666</a></p> <p>[3] A.O. Idris, E.O. Oseghe, T.A.M. Msagati, A.T. Kuvarega, U. Feleni, B. Mamba, <em>Sensors</em>, 20, 5743, 2020.<u>doi:10.3390/s20205743</u></p> <p>[4] Y. Wang, X. Yang, Z. Gu , H. Qin, L. Li , J. Liu, X. Yu, <em>Materials Science and Engineering C, </em>66, 185–192, 2016. <u>http://dx.doi.org/10.1016/j.msec.2016.04.065</u></p> <p>&nbsp;</p> <p>&nbsp;</p> Vishwapriya U. Copyright (c) 2021 Vishwapriya U. https://spast.org/techrep/article/view/2779 Tue, 19 Oct 2021 00:00:00 +0000 Compressive Behavior of Tamarind Shell Powder and Fine Granite Particles Reinforced Epoxy Matrix Based Hybrid Bio-Composites https://spast.org/techrep/article/view/1828 <p>Nowadays, hybrid bio-composites are being developed by combining different natural resources as reinforcement and filler components, and this has raised their necessary qualities dramatically. An epoxy resin matrix for compressive qualities was tested experimentally with the inclusion of fine granite powder and tamarind shell powder particles. As reinforcement materials, fine granite powder and tamarind shell powder are employed. Specimens of hybrid bio-composite were created by altering the reinforcement material weight % while maintaining the epoxy resin weight percentage the same. Utilizing a compression moulding process, composite boards made of hybrid biomaterials were created. Water jet machining is used to remove hybrid bio-composite specimens for compression tests in accordance with ASTM standards from the hybrid bio-composite boards. When fine granite and tamarind shell powder particles are added to the epoxy resin matrix, experimental results show that the compressive characteristics of the hybrid bio-composites are greatly improved.</p> Mayakannan Selvaraju, R. Girimurugan, Ganesh Babu Loganathan, G. Sivaraman, C. Shilaja Copyright (c) 2021 Mayakannan Selvaraju, R. Girimurugan, Ganesh Babu Loganathan, G. Sivaraman, C. Shilaja https://spast.org/techrep/article/view/1828 Sat, 09 Oct 2021 00:00:00 +0000 Development of hydroxyapatite coating on Titanium alloy for orthopedic applications https://spast.org/techrep/article/view/2947 <p>Biomaterials are synthetic materials that are utilized to restore or replace damaged or diseased human body parts, allowing them to regain their original form and function to improve the quality and longevity of human life. Titanium and its alloys have long been employed in biomedical applications due to its remarkable features, such as good biocompatibility, resistance to bodily fluid effects, tremendous tensile strength, flexibility, and high corrosion resistance. Titanium and its alloys have a unique combination of strength and biocompatibility that makes them suitable for medical or recreational purposes. If these materials are used as bio-implant, it releases toxic ions like aluminium and vanadium in the body fluid environment after implantation. [1-3]. To overcome the problem, Ti6Al4V alloy was coated with hydroxyapatite (HAp) which provides better bioactivity, osteocompatibility, and antibacterial activity. This layer prevents the further passing of ions from the biomaterial and improves the tissue growth on the bone. The present work is to synthesize HAp from snail shells using a simple wet precipitation method.[4]. The waste material of snail shells can be utilized for the development of the HAp which was non-toxic, eco-friendly, and also to improve bioactivity and biocompatibility of the biomaterials. The prepared HAp was coated on the Ti6Al4V alloy by using the electro-deposition method.[5]. The coated alloy was characterized by various techniques such as FTIR, XRD, FESEM, EDAX, and AFM. The corrosion resistivity of the coated and uncoated samples was tested by immersing them in SBF solution at 370 C using the cyclic voltammetric method. The corrosion resistance property was increased from pristine sample to coated sample. The two different bacterial strains like Staphylococcus aureus and Escherichia coli were used for testing the antibacterial activity of the sample. It is concluded that HAp coated Ti6Al4V alloy may be considered a better material for orthopedic applications.</p> <p>&nbsp;</p> <p>&nbsp;</p> NAGALAKSHMI R, Ms.M.Kalpana Copyright (c) 2021 NAGALAKSHMI R, Ms.M.Kalpana https://spast.org/techrep/article/view/2947 Fri, 05 Nov 2021 00:00:00 +0000 Stable synthesis of Borophene as catalyst for hydrogen evolution reaction https://spast.org/techrep/article/view/939 <p>To overcome the shortage of fossil fuels, environmental pollution, and global energy demand,<br>there is a need for efficient, relatively cheap, earth-abundant, and clean energy sources which<br>can replace the traditional depleting energy resources. Hydrogen (H2) is a prime candidate<br>among all chemical fuels which has been in focus as an alternative to traditional fossil fuels<br>owing to its clean, environment-friendly, and zero-emission. Electrochemical water splitting is<br>the most efficient and cost-effective method to produce high purity hydrogen (H2) than other<br>existing methods. In hydrogen evolution reaction (HER), catalyst plays a major role. Currently,<br>precious metals such as Pt, Pd, etc., are being used as catalyst which are expensive, less<br>durable and can’t be produced in large scale. Extensive research is being carried out for the<br>low cost, and non-metal based catalysts such as transition metal oxides, chalcogenides,<br>phosphides, nitrides, metal alloys, and carbides.<br>1 Among the various materials, twodimensional (2D) materials have important advantages that can be used as catalysts, they<br>have a high specific surface area which is beneficial for sufficient exposure of active sites, the<br>catalytic enhancement properties of 2D materials can be tuned by doping with transition<br>metals or functionalizing the surface with other suitable derivatives</p> Mohammed Abzal shaik Copyright (c) 2021 Mohammed Abzal shaik https://spast.org/techrep/article/view/939 Thu, 16 Sep 2021 00:00:00 +0000 Biogenesis of MnO2 nanoparticles using Momordica charantia leaf extract https://spast.org/techrep/article/view/306 <p>In this present study, an easy, eco-friendly and efficient method for the biogenesis of manganese dioxide nanoparticles (MnO<sub>2</sub> NPs) using <em>Momordica charantia</em> leaf extract is discussed. The MnO<sub>2</sub> NPs were synthesised by reduction of potassium permanganate using <em>Momordica charantia</em> leaf extract as a reducing agent. Fourier-transform infrared spectra exposed the contribution of the biomolecules in the <em>Momordica charantia</em> leaf extract for the formation of MnO<sub>2</sub> NPs [1]. The UV–visible spectrum of the biosynthesized MnO<sub>2</sub> NPs displayed absorption peaks at 371 nm, which was the absorption maximum of MnO<sub>2</sub> NPs [2, 3]. Crystal phase and crystalline size of the biosynthesized MnO<sub>2</sub> NPs was characterised by X-ray diffraction analysis [4]. The X-ray diffraction pattern indicated that the average size of MnO<sub>2</sub> NPs was about 36.01 nm. The field emission scanning electron microscopy analysis revealed that the biosynthesized MnO<sub>2 </sub>NPs have irregularly spherical shape with 16 – 63nm in size. EDAX confirmed the presence of Mn and O in the MnO<sub>2</sub> NPs.&nbsp; The antibacterial activities of MnO<sub>2</sub> NPs were evaluated against <em>Bacillus amyloliquefaciens, Bacillus subtilis</em> and <em>Bacillus cereus.</em> The total antioxidant capacity was evaluated by phosphomolybdenum method. The biosynthesized MnO<sub>2</sub> NPs have significant antibacterial activity and antioxidant activity.</p> Alwin David S, Ramkumar P Copyright (c) 2021 Alwin David S, Ramkumar P https://spast.org/techrep/article/view/306 Tue, 14 Sep 2021 00:00:00 +0000 An overview of cutting-edge self-healing materials https://spast.org/techrep/article/view/2165 <p><strong>Abstract</strong></p> <p>&nbsp;</p> <p>There is an adage that states “a small crack breaks a big dam” and in this context, it is important to mention that high-rise buildings and long bridges are susceptible to accidents and disasters every hour of every day, which strongly justifies the research in the area of materials which can auto-repair by themselves. A small imperfection or microcracks of the materials may result into premature failure if it is not detected or repaired in time. Some of these microcracks are formed within the material structures, which are invisible, difficult to repair manually, and lead to catastrophic failure before the service life of the products [1]. Self-repairing strategies inspired by nature, have been investigated in biomimetic engineering in order to automatically detect and restore the damaged materials. These bio-inspired engineered materials, i.e., materials that “self-heal” after external damage, have been explored since the early 1990s [<a href="https://www.mdpi.com/2073-4360/13/14/2297/htm#B2-polymers-13-02297">2</a>]. The damage can mostly be repaired by the systematic transport and the polymerization of healing materials in the damaged area. It is important to mention that the majority of early studies on self-healing materials were conducted utilizing polymer materials [<a href="https://www.mdpi.com/2073-4360/13/14/2297/htm#B2-polymers-13-02297">3</a>]. Polymeric materials were found to be more useful when encapsulated in microcapsules, prepared as nanofibers, or used in a reversible form, such as a thermoplastic or supramolecular material; additionally, these materials were viable and did not require external stimulation to initiate the healing process [<a href="https://www.mdpi.com/2073-4360/13/14/2297/htm#B4-polymers-13-02297">4</a>]. However, from the mechanical strength perspective, polymer based materials are inevitably soft and weak. To date, several self-healing materials have been explored; however, the mechanical properties of those materials limit their practical applications.</p> <p>Therefore, the next target is the development of self-healing materials is to engineer materials with sufficient mechanical strength for use as structural materials. As for example, the walls of a nuclear power plant or an airplane frame must exhibit adequate strength under extreme conditions. For this reason, healing materials for use in these applications are also required to be sufficiently strong, reflecting that the traditional polymer-based materials are inherently not applicable. Till date, many cutting-edge materials have been investigated to repair hard materials, such as concrete composites, carbon fiber-reinforced plastic (CFRP) composites [5], steel, and aluminum. In this state-of-the-art review, novel fabrication techniques of self-healing materials with considerably high mechanical strength are elucidated. We also outline the challenges associated with these materials as well as their structural modification strategy for better performance.</p> Dr. Jyoti Rawat Copyright (c) 2021 Dr. Jyoti Rawat https://spast.org/techrep/article/view/2165 Fri, 08 Oct 2021 00:00:00 +0000 Substrate dependent analysis of MIM Capacitors for Resistive random-access memory Applications https://spast.org/techrep/article/view/496 <p>Simple construction, great CMOS compatibility, low operation current/voltage, high density, and super rapid switching rates (10ns), has made resistive random-access memory (RRAM) one of the most desirable new Non-volatile Memory [1-4]. Transition-Metal-Oxides have been demonstrated to be excellent RRAM materials [3]. Also due to the generation of oxygen vacancies, ion irradiation has been found to improve RRAM properties [4]. Because of its fab-friendly properties and dielectric constant (k=10), ZnO is one of the most promising materials among them.</p> <p>The present study focusses on the fabrication of Metal/MOx/Metal for RRAM application. The conduction behaviours which is responsible for switching behaviours in the Low resistance state (LRS) and High resistance state (HRS) non-volatile switching has been analysed in detail. A ZnO thin film with a thickness of 120-140 nm was grown on Au deposited Si and ITO coated glass substrate as shown in Fig. 1. The stoichiometry of metal oxide film has been measured by Resonant Rutherford back Scattering (RRBS) of ZnO coated Au deposited Silicon available at IUAC, Delhi as shown in Fig 2.</p> <p>X-ray diffraction (XRD) analysis was used to characterize the crystalline structures of Au-deposited ZnO on ITO samples. The X-ray diffraction data for a typical ITO/ZnO/Au heterostructure is shown in the Fig 3 below. It was observed that the desired (002)-oriented ZnO wurtzite phase exists. With the use of pressure contact, we have investigated I-V characteristics and determined that ZnO with ITO coated substrate provides the best switching behaviour. The identical model was designed using COMSOL Multiphysics [5-6] software was used for validation, and the metal rich characteristics enhancement is studied as shown in Fig 4</p> SHIKHA KAUSHIK, SUJATA PANDEY, RAHUL SINGHAL Copyright (c) 2021 SHIKHA KAUSHIK, SUJATA PANDEY, RAHUL SINGHAL https://spast.org/techrep/article/view/496 Wed, 15 Sep 2021 00:00:00 +0000 Systematic Investigation on the Plasmonic Properties of Au NPs/ITO with Varying Annealing Process and Film Thickness https://spast.org/techrep/article/view/1170 <p>Noble metal nanoparticles are the topic of profound interest on account of their exceptional physical properties contrary to their bulk counterparts [1]. We report here the fabrication of sputter-deposited Au nanoparticles on ITO (Sn doped Indium Oxide) coated glass substrate. The effect of varying annealing parameters viz. time and temperature in conjunction with varying thickness parameters have been thoroughly investigated. Prepared thin films were characterized using FE-SEM (Field emission scanning electron microscope), RBS (Rutherford backscattering) measurement, and optical absorbance spectroscopy. The role of annealing temperature and duration on the evolution of Au nanoparticles is discussed. At low temperature, film dewetting has been observed while high temperature and longer duration of annealing leading to particle dissolution for the greater thickness of 5 nm and 8 nm for Au thin films. According to the study, 5 nm thickness Au thin film which was annealed at 500<sup>o</sup>C for 90 min exhibited maximum SPR (surface plasmon resonance) effect.&nbsp;&nbsp;&nbsp;&nbsp;</p> Anuradha Verma Copyright (c) 2021 Anuradha Verma https://spast.org/techrep/article/view/1170 Fri, 24 Sep 2021 00:00:00 +0000 EFFECTIVE DEPTH OF BC SOIL AND ITS VARIATION WHEN MODIFIED WITH COIR FIBRE https://spast.org/techrep/article/view/1668 <p>The main objective of the manuscript is to investigate the basic qualities of BC Soil (BCS) and <br>coir fibre, as well as to reduce construction costs by utilizing naturally occurring coir fibres and <br>industrial waste products. To determine the strength of BCS, different sizes of model footings <br>of 0.05m are reinforcing to Treated Coir Fibre (TCF) resting on loose stratum. A comparison <br>is made between TCF-reinforced BCS and unreinforced BCS under static load conditions. <br>Blending with TCF in various proportions for different densities and experimenting with new <br>chemicals or compounds that make coir fibre more water repellent can also be done. The full <br>results of this study are concluded as for distinct settlements of footings carried by RDCFs <br>based on the laboratory experiments results and observation gained owing to the addition of <br>TCF to BCS. B-footing depths of 0.2B, 0.4B, 0.6B, 0.8B, 1B, 1.2B, 1.4B, 1.6B, 1.8B, and 2B <br>are the reinforcing depths for reinforced soils. The earth is impacted to a depth of 2 to 2.5 <br>times the breadth of the footing, indicating that the size of the footing is growing.</p> Shashank S T Copyright (c) 2021 Shashank S T https://spast.org/techrep/article/view/1668 Fri, 08 Oct 2021 00:00:00 +0000 Chitosan/PVA Incorporated with Nickel Oxide Nanoparticles for Wound Dressing Applications https://spast.org/techrep/article/view/2355 <p>The skin is the largest and the outermost organ of the human body, and it plays a vital role as the protective barrier against external damage and pathogens. It has various functions, such as controlling body temperature, regulating water loss, protecting blood vessels and nerves, and sensing [1]. The aforementioned action will not operate properly if the skin is damaged. Any injury to the skin makes a gateway for microorganisms to penetrate into our body and proliferate and cause harmful infection. Wound healing is a natural healing process in the human body. The wound healing mechanism comprises four extensive, overlapping phases, hemostasis, inflammation, proliferation and tissue remodeling. Furthermore, the properties of biopolymer and synthetic polymers were modified by blending them with nanoparticles, so that these materials can be used as a wound dressing application [2,3].</p> <p>In this current work, a polymeric blend based on chitosan (CS)/poly(vinyl alcohol) (PVA) containing different concentrations of nickel oxide nanoparticles (NiO NPs) (0.5, 1.5, 3, and 5wt%)were prepared by solution casting technique as shown in Fig.1. A [4]. Nickel oxide nanoparticles were prepared by a sol-gel method and characterized spectroscopic techniques like X-ray Diffraction (XRD), scanning Electron Microscope (SEM), High Resolution Transmission Electron Microscopy (HRTEM) and Energy Dispersive X-Ray Analysis (EDX) were used to analysis the physico-chemical properties of the sample. The synthesised NiO nanoparticles are verified with XRD patterns which clearly shows that diffraction peaks of the (111), (200), (220), (311), and (222) crystal planes, which corresponds to the face-centred-cubic (fcc) structure of the NiO NPs. Using the Debye-Scherrer equation and by considering each diffraction peak broadening, the crystallite size was obtained to be 28.7 nm. Furthermore, the obtained films were characterized using XRD, SEM and thermogravimetric analysis (TGA). The XRD patterns of the prepared samples reveal miscibility between the amorphous components of the CS/PVA/NiO NPs blend. The XRD pattern of chitosan/PVA film shows only one diffraction peak at 2θ = 19.3˚, whereas the other diffraction peaks of both PVA and chitosan are disappeared. For the XRD patterns of chitosan/PVA sensitized with a different weight percentage of NiO NPs, there is a shift toward a higher theta degree with an increasing weight percentage of NiO NPs and its broadening is decreased compared to pure chitosan/PVA film. In addition, increasing NiO NPs percent in polymer matrix up to 5 wt%, resulting in the appearance of additional peaks at 2θ = 37.4<sup>◦</sup>, 43.4<sup>◦</sup>, 62.6<sup>◦</sup>, 75.1<sup>◦</sup> and 79.4<sup>◦</sup>, which are attributed to NiO NPs as shown in Fig.1. B. The obtained results were proved the incorporation of NiO NPs into the nanocomposite films. The presence of -NH<sub>2</sub> group in chitosan and -OH group in PVA, CS/PVA/NiO NPs nanocomposite films was confirmed by FT-IR analysis. The formation of CS/PVA/NiO NPs nanocomposite films was formed uniformly blended, clearly noticeable in SEM. The prepared nanocomposite films were characterized the following properties such as swelling, degradation, tensile strength, and in-vitro wound healing. CS/PVA/NiO NPs nanocomposite films demonstrated significant antibacterial activity against wound pathogens and improved wound healing, which will confirmed by MTT assay and migration assays. <em>In vitro</em> analysis will ensure that CS/PVA/NiO NPs nanocomposite films have potential capability to use as a wound dressing material.</p> GOBI R, Ravi Shanker Babu Copyright (c) 2021 GOBI R, Ravi Shanker Babu https://spast.org/techrep/article/view/2355 Fri, 08 Oct 2021 00:00:00 +0000 Synthesis of Ni0.5Co0.5Fe2O4 ferrite and effect of annealing temperature on the structural, morphological and dielectric analysis. https://spast.org/techrep/article/view/680 <p>In the last decade, research on the synthesis and characterization of nanosized ferrites have highly increased, and a wide range of new applications for these materials have been identified. The ability to tailor the structure, chemical, optical, magnetic, and electrical properties of ferrites, by selecting the synthesis parameters further enhanced their widespread potential technological applications. Ferrites having their specialized characteristics like low electrical properties and losses etc, variation at low to high frequencies creates distinguished industrial employment with advanced technology[1].The nano-ferrites being confined to microwave device applications (phase shifters, circulators, isolators) due to their considerable low electrical conductivity and dielectric losses at gigahertz frequency range [2,3], has now become challenging as well as trending task to control the electrical conductivity at high frequencies. But nevertheless, the efforts have been going on to achieve the required properties, based on desired applications.</p> <p>Among various ferrites, CoFe<sub>2</sub>O<sub>4</sub>, MnFe<sub>2</sub>O<sub>4</sub>, ZnFe<sub>2</sub>O<sub>4</sub>, NiFe<sub>2</sub>O<sub>4</sub>, and CuFe<sub>2</sub>O<sub>4</sub> have attracted considerable attention due to numerous applications, as mentioned above. CoFe<sub>2</sub>O<sub>4</sub> and NiFe<sub>2</sub>O<sub>4</sub> grow in spinel-type crystal structures, which can be represented by (Fe<sup>3+</sup>) [Co<sup>2+</sup>Fe<sup>3+</sup>] O<sub>4</sub> and (Fe<sup>3+</sup>) [Ni<sup>2+</sup>Fe<sup>3+</sup>]O<sub>4</sub>, respectively[4]. Recently, nanoparticles of Cobalt ferrites (CF)-based materials have gained remarkable interest due to their important conducting and insulating properties. Due to higher values of magnetostriction cobalt ferrites can be used for strain sensor and actuator applications [5]. Similarly, cobalt ferrite, nickel ferrite is also one of the suitable candidates for applications in the family of spinel ferrite. Nickel ferrite possesses high electrical resistivity, high saturation magnetization, high Curie temperature, low eddy current and dielectric losses [6,7]. The investigation of the reports suggests that, mixed ferrite possesses better properties and stability depending on the stoichiometry and nature of cations in the final compositions. Electrical and dielectric properties, along with magnetic properties of nanocrystalline mixed Ni-Co ferrites have been reported in the literature survey [8-10]. Gangatharan Sathishkumar, et al. [11] investigated the structural and dielectric properties of nano-particles of Co<sub>(0.5-x)</sub>Ni<sub>x</sub>Zn<sub>0.5</sub>Fe<sub>2</sub>O<sub>4 </sub>(x=0 to 0.3) prepared by co-precipitation method. Mangala U. Sawal, et.al [12] proposed research work which manifests the comparison of nanosized ‘as prepared’ Ni<sub>0.5</sub>Co<sub>0.5</sub>Fe<sub>2</sub>O<sub>4</sub> ferrite with their ‘sintered’ counterpart concerning their effect on the structural and magnetic properties.</p> <p>Likewise, various researchers have reported their work on the specific stoichiometric Ni<sub>0.5</sub>Co<sub>0.5</sub>Fe<sub>2</sub>O<sub>4</sub> nanoparticles using various dry and wet chemical synthesis methods, along with the temperature variation concerning for various sintered samples. But, reports on the fabrication of stoichiometric Ni<sub>0.5</sub>Co<sub>0.5</sub>Fe<sub>2</sub>O<sub>4</sub> NPs in pure spinel phase system, along with the effect of high annealing temperature on the structural, morphological and dielectric properties have been scarce in the literature.</p> <p>The present study revolves around the main objective to synthesize Ni<sub>0.5</sub>Co<sub>0.5</sub>Fe<sub>2</sub>O<sub>4</sub> ferrite via combining the sol-gel auto-combustion methods that results in a simple and inexpensive preparation method for high purity, homogenous nano powders. The nanoparticles were further sintered at three different temperatures (850<sup>o</sup>C, 1050<sup>o</sup>C, 1150<sup>o</sup>C). Ferrite as single-phase system was obtained at temperature above 1000<sup>o</sup>C. The fundamental aim of the work is to obtain different size of NPs and study their effect, on the dielectric properties for the storage device applications. On the contrary, there is also considerable interest in understanding new materials where effect of magnetic field on dielectric properties have gained rich flavour of physics for materials, such as Magneto-dielectrics. The NPs were further characterized using XRD, FTIR, XPS, FESEM, EDX, and IS impedance spectroscopy, was performed for investigating the structural, morphological, and dielectric properties of the ferrite nanoparticles.</p> simrandeep kour, Rupam Mukherjee, Nitish Kumar Copyright (c) 2021 simrandeep kour https://spast.org/techrep/article/view/680 Sat, 18 Sep 2021 00:00:00 +0000 Two-Dimensional Nanomaterials and Their Derivatives as Effective Antimicrobials https://spast.org/techrep/article/view/170 <p>Millions of people die all around the world due to microbial infection-related diseases every year [<a href="#_ENREF_1">1</a>]. The atrocious situation occurred due to the abusive use of antibiotics, especially in developing countries. Increasing instances of antibiotic resistance due to the emergence of superbugs have led to burgeoning research interest in the development of new generation antibacterial. Hence, to sustain a prosperous society critical approach must be taken in the development of novel bactericidal weapons. Reports have revealed the considerable disinfecting ability and biocompatibility of two-dimension nanomaterials (2D-NMs) [<a href="#_ENREF_2">2</a>]. Recently, new 2D-NMs beyond graphene, such as MXenes, Transition Metal Dichalcogenides (TMDs), Black phosphorous (BP), Layered Double Hydroxides (LDHs), graphitic carbon nitride (g-C<sub>3</sub>N<sub>4</sub>), have been tremendously explored for their application as antimicrobials against different strains of bacteria [<a href="#_ENREF_3">3</a>]. The 2D-NMs due to their interesting ultrathin structure and intriguing physiochemical properties such as optical, magnetic, and electronic properties can be recognized as suitable candidates for sterilization [<a href="#_ENREF_4">4</a>]. The key property that controls the optical and electrical properties is the bandgap. In particular, 2D-NMs exhibits a highly tunable bandgap that may be achieved by controlling the number of layers, hetero structuring, strain engineering, chemical doping, alloying, intercalation, substrate engineering as well as external electric field [<a href="#_ENREF_5">5</a>]. Graphene with zero bandgaps behaves as metal [<a href="#_ENREF_6">6</a>], whereas the TMDs family is composed of semiconductors (MoS<sub>2</sub>, MoSe<sub>2</sub>), metals (NbTe<sub>2</sub>, TaTe<sub>2</sub>), and superconductors (NbS<sub>2</sub>, NbSe<sub>2</sub>) corresponding to different band gaps [<a href="#_ENREF_7">7</a>]. The antibacterial mechanism of 2D-NMs is attributed mainly to the direct physical interaction, reactive oxygen species (ROS) generation, light-mediated photothermal therapy, metal ion incursion, piezoelectric effect, photocatalytic ablation, and Polysulfane release [<a href="#_ENREF_8">8-11</a>]. Following these multiple biological pathways, the 2D-NMs in comparison to antibiotics are less resistible. The interplay between nanosheets and bacteria leads to deleterious degradation of cellular components, proteins, lipids, and nucleic acids and ultimately leads to bacterial cell death [<a href="#_ENREF_12">12</a>]. The antibacterial performance of these 2D-NMs can be tuned by changing shape, size, and orientation of the nanosheet [<a href="#_ENREF_13">13</a>, <a href="#_ENREF_14">14</a>], by functionalizing with different functional groups such as NH<sub>2</sub>, SH, COOH [<a href="#_ENREF_15">15</a>], etc., by incorporation of metal nanoparticles (NPs), metal oxide NPs [<a href="#_ENREF_16">16</a>], halogens, polymers or quaternary ammonium/phosphonium salts [<a href="#_ENREF_17">17</a>] into the 2D-NMs nanosheets. On modification, these nanohybrids exhibit enhanced antibacterial activity against most common bacterial strains such as <em>E. coli, B. sublitis, S. aureus, P. aeruginosa &nbsp;</em>[<a href="#_ENREF_18">18</a>, <a href="#_ENREF_19">19</a>], etc. The bactericidal efficiency of different nanohybrids can be determined by the agar disk diffusion method, direct contact test, fluorescence-based-bioassay test, and flow cytofluorometric method [<a href="#_ENREF_20">20</a>].</p> <p>Based on the previous reports, more studies need to be conducted to further unveil the antibacterial mechanism for bacterial ablation and explore their practical applications in clinical trials. Construction of 2D-NMs based materials for efficient and non-invasive antimicrobial applications is still an imperative matter. Additionally, some other novel antibacterial strategies like Z-scheme heterojunction and photoelectrochemical sterilization, are still under construction and are worth advances in this field [<a href="#_ENREF_21">21</a>, <a href="#_ENREF_22">22</a>].</p> <p>Through an online poster presentation, in this webinar, I am presenting the antimicrobial efficacy and potential of different 2D NMs and will also highlight the importance of these materials towards future medicine and technologies. Finally, the implications of these materials over traditional antimicrobials including antibiotics, antiseptics, antimicrobial peptides will also be presented. Eventually, we will address the challenges and future development trends of 2D-NMs as antibacterial.</p> Shruti Copyright (c) 2021 Shruti https://spast.org/techrep/article/view/170 Thu, 02 Sep 2021 00:00:00 +0000 Temperature-Induced Phase Transitions in Fe-Ga Alloys for Sensors https://spast.org/techrep/article/view/1880 <p>Over the last few years, Fe-Ga magnetostrictive alloys (also referred to as Galfenol), which are among the most important functional magnetic materials, have found their way into sonar systems and sensors such as displacement and force sensors,&nbsp; acoustic , tactile and torque sensors [1]. It has already been found that the addition of Ga increases the magnetostriction of bcc Fe by a significant amount. At room temperature, the magnetostriction of Fe–Ga alloys can be ten times greater than that of bcc Fe. Additional advantages of these alloys are their low associated cost, high ductility, high mechanical strength, and ability to withstand high imposed stress levels have drawn considerable attention [2]. Golovin et al. [3] demonstrated that after casting, alloys&nbsp;with &nbsp;Ga&nbsp;27 at. percent possess the D0<sub>3</sub> structure and that the first-order L1<sub>2</sub> to D0<sub>19</sub> transition occurs at 893 K. Additionally, for the first time, it was observed that the phase transition from one ordered phase to another ordered phase involves disordered states. When temperature transformation processes, most notably cooling from A2 to high temperature phase&nbsp;occur, the phase diagrams of Fe-Ga alloys undergo ordering and disordering structure changes. A faster cooling rate indicates that the alloys prepared at room temperature are a mixture of A2, L1<sub>2</sub>, and D0<sub>3</sub> phases [4]. The magnetostrictive, structural, thermal, and magnetic properties of galfenol alloys with various compositions were investigated after they were arc melted and heat treated followed by furnace cooling. The X-Ray Diffraction analysis confirms the body-centered cubic structure of the alloys and the presence of the A2 and D0<sub>3</sub> phases. Additionally, optical microscopy confirmed the presence of equiaxed A2 phase grains which are responsible for the larger grain boundaries [5]. Crystallite size and grain size increment also indicates that phase transition happens in the alloys. &nbsp;The differential scanning calorimetry confirms the presence of the A2, B2, D0<sub>3</sub>, and L1<sub>2</sub> phases. Fig. 1 shows the crystal structures of phases present in the Fe-Ga alloys and sequence of phase transition. The process of transition&nbsp;from one ordered phase to another is characterised by disordering processes. Recorded phase transition sequence is &nbsp;&nbsp;The decrement in magnetization in particular temperature are due to change in magnetic properties in D0<sub>3</sub>, that does not corresponds to phase transitions [6]. A vibrating sample magnetometer was used to determine the saturation and remanent magnetization. When it comes to saturation magnetization, grain size is inversely proportional to it. Particularly, the magnetic properties of Fe-Ga alloys are significantly influenced by the structural ordering and microstructure of the alloys. This demonstrates that our Fe-Ga alloy has been optimised for use as a sensor and actuator applications.</p> Vijayanarayanan V, Himalay Basumatary, M. Manivel Raja, V. Aravindan, M. Mahendran Copyright (c) 2021 Vijayanarayanan V, Himalay Basumatary, M. Manivel Raja, V. Aravindan, M. Mahendran https://spast.org/techrep/article/view/1880 Fri, 08 Oct 2021 00:00:00 +0000 Feasibility of Development of Fibre Reinforced Aluminium Composites using Friction Stir Processing - A Review https://spast.org/techrep/article/view/1916 <p>There is a constant demand for high performance materials in the structural applications for the fields of aerospace and automobile engineering. In this direction, several advancements in the material processing technologies have yielded novel materials for the purpose. One such category of materials is the Fibre reinforced Aluminium Composites. These composites offer unique properties for the design of structural components in aerospace and automobile industries, in that, they are both lightweight and strong. Several researches have been carried out in the regard, and the literature is available for the different methods used to add these reinforcements, with appropriate tooling and process parameters.<br>Friction Stir Welding (FSW) is a solid-state joining technique invented at The Welding Institute (TWI) (Cambridge, United Kingdom) in 1991. The basic concept of FSW is remarkably simple [1-2]. A non-consumable rotating tool with a specially designed pin and shoulder is inserted into the abutting edges of plates, to be joined and then traversed along the line of joint when the shoulder touches the plates. The tool heats the workpieces and moves the material to produce the joint. The heating is achieved by the friction between the tool and workpieces and by the plastic deformation of the material. Localized heating softens the material around the pin and the combination of tool rotation and translation results in the movement of material from the front to the back of the pin. Thus, a welded joint is produced in solid state. Friction Stir processing (FSP), developed based on the basic principles of friction stir welding (FSW), is a solid-state joining process originally developed for aluminium alloys, is an emerging metalworking technique that can provide localized modification and control of microstructures in near-surface layers of processed metallic components. Friction Stir Processing (FSP), is one of the emergent methods that can be used to produce Aluminium Surface Composites, suitable for aerospace and automobile applications. The FSP causes intense plastic deformation, material mixing, and thermal exposure, resulting in significant microstructural refinement, densification, and homogeneity of the processed zone. The FSP technique has been successfully used for producing the fine-grained structure and surface composite, modifying the microstructure of materials, and synthesizing the composite and intermetallic compound in situ [3]. However, the application of this method to form Fibre reinforced Aluminium Composites remains less explored. It is important to explore this possibility as these materials can potentially replace aluminium laminates presently being used in aerospace applications, in that they lack the strength in lateral direction of bonding. Also, these materials can prove to be of great use in ballistic applications for military and defence fields. With this vision, this review paper aims to present the current status of research on the fabrication of aluminium fibre reinforced composites [4-5]. The review also aims to shed light on the favourable aspects of FSP for the development of fibre reinforced aluminium composites and it also points out the potential improvements FSP can bring to the material being formed, in contrast to the other fabrication processes presently being used for the purposes.</p> Nagappa Pattanashetti, Suresha C N Copyright (c) 2021 Nagappa Pattanashetti, Suresha C N https://spast.org/techrep/article/view/1916 Sat, 09 Oct 2021 00:00:00 +0000 The correlation of anisotropic silver nanoparticle shape and optical properties https://spast.org/techrep/article/view/1997 <p>This article reports the shape-dependent optical properties of anisotropic silver nanoparticles. Anisotropic silver nanoparticles with controlled shapes have been synthesized by solvothermal process. The process involves the reduction of silver nitrate in dimethyl formamide with the help of surface regulating polymer (polyvinylpyrrolidone). The shape of the nanoparticles has been controlled by varying the reaction time. TEM studies show that the synthesized nanoparticles have different shape and size for different reaction times. The absorption spectra of the synthesized nanoparticles show three distinct bands that can be attributed to the in-plane dipole, out-of-plane dipole, and out-of-plane quadrupole resonance. The peak positions of the absorption bands and intensities shift with the change in shape and size of the nanoparticles. The slight change of shape like edge truction changes the absorption spectra significantly. The correlation between the absorption spectra and shape of anisotropic nanoparticles has been established.</p> Dr. Divya Jindal, Dr. Rajesh Kumar Copyright (c) 2021 Dr. Divya Jindal, Dr. Rajesh Kumar https://spast.org/techrep/article/view/1997 Fri, 08 Oct 2021 00:00:00 +0000 Synthesis of silicon dioxide nanoparticles by sol-gel method for application in geopolymer composites https://spast.org/techrep/article/view/2626 <p>The advent of nanotechnology has revolutionized the majority of the sectors of science and technology [1]. Nanotechnology was introduced by Richard P Feynman in 1959 through a lecture on “There is plenty of room at the bottom”. It is the re-engineering of materials and devices by monitoring matter at an atomic scale [2].&nbsp; Synthesis of pure and nano-sized particles is still a challenge despite many pre-established processes. The size of the nanoparticle is of prime importance as the finer nanoparticles exhibit quicker reactions due to increased surface area. A pure material is essential to produce a good end product without any impurities. Specific properties of nanoparticles can be monitored at the nanoscale and it is influenced by the synthesis procedure. Nanoparticles are synthesized by various methods such as gas condensation, vacuum deposition &amp; vaporization, chemical vapor deposition &amp; condensation, mechanical attrition, chemical precipitation, sol-gel synthesis, and electrodeposition [3]. The sol-gel method of synthesis can control the size and morphology of nanoparticles. It is one of the simplest ways to produce nano-sized particles in the pure form via a bottom-up approach. The sol-gel method of synthesis has added advantages over other methods because of its versatility, homogeneity, and modification of particle properties by modifying the parameters of synthesis [4].</p> <p>Nano silica has gained importance because of its low density, mechanical and chemical stability. The use of nano-silica in cement/geopolymer composites would enhance the workability, strength, density, and durability. It also reduces setting time and porosity [5]. In this study, silica nanoparticles were synthesized by the sol-gel method. Sodium Silicate was used as precursor with ethanol as solvent. CTAB and Ammonia were used as surfactant and reducing agent respectively. It was characterized using Scanning Electron Microscope (SEM), X-ray Diffraction (XRD), Energy dispersive X-ray analysis (EDAX), and Particle size distribution (PSD). The SEM and EDAX data are shown in figure 1.</p> <p>The silica nanoparticles obtained were mostly spherical with an average particle size distribution of 26nm and 99% purity. The synthesized silica nanoparticles were incorporated in geopolymer composites to study the impact of nanoparticles on the properties of the composites.</p> Ujwal Shreenag Meda, Sachin K C, Radhakrishna Copyright (c) 2021 Ujwal Shreenag Meda, Sachin K C, Radhakrishna https://spast.org/techrep/article/view/2626 Sun, 17 Oct 2021 00:00:00 +0000 Assessment of Anticorrosive Coatings with Multicore Microcapsules and Polyaniline Nanoparticles: A Novel Synergistic Approach https://spast.org/techrep/article/view/1565 <p>Corrosion of metallic material followed by steady degradation in performance in their service life is a common natural fate world faced. It leads to premature failure in various technical fields causes tremendous economical losses cause slow down of economical growth [1]. Therefore is important to select the effective and affordable mode of decrease the deteriorating effect of corrosion of structures. There are different methods to reduce the such effect but most common and cost effective method is organic coatings, which increase the corrosion resistance and as result long life durability of steel material [2]. However, these coatings suffer from the distraction due to mechanical or chemical action in their service time to form micro cracks, which further propagate to form cracks and expose the coated material to moisture and oxygen to damage. These micro crack are difficult to detect and nearly impossible to repair by conventional methods [3-4].To overcome this issue firstly there was attempt to introduce self healing material in 2001. White S. R. and co-worker encapsulated endo-dicyclopentadine as a healing agent in microcapsule and embedded in epoxy resin matrix along with Grubb’s catalyst [5]. Self healing material is new type material to design for polymeric material to investigate the cracks in early stage and repair damage without external intervention.Whenever the micro crack generate in coating matrix, it breaks the embedded microcapsule as a result release of healing active agent in cracks by capillary action in damage surface. The released healing agents polymerized by react with catalyst present in matrix or react with oxygen to repair the damage [6]. But these catalysts are rare and costly.</p> <p>Nowadays, various self healing mechanisms have been developed. The intrinsic conducting polymers like polyaniline can be used in internal sacrificial electrode formation, which gives the protection to the coated material from corrosion. But polyaniline is not dissolving in common organic solvent hence its nanoparticles are incorporated in the coating matrix [3]. Therefore researchers are attracted toward the new approach of self healing anticorrosion by encapsulation method.</p> <p>In microencapsulation the poly urea-formaldehyde shell material is extensively used though there are different types of shell materials have been investigated along with the core material healing agent for epoxy resins like dicyclopentadine [7], various drying oils such as linseed oil, Tung oil and alkyd resins,Soyabeen oil [8]. Drying oils are triglyceride of long chain unsaturated fatty acids used as auto-oxidative healing agent in microencapsulation. The auto-oxidative reaction occurs in aerial oxygen in atmosphere without any catalyst [9].However, release of oil takes place only once whenever the crack generated. It is attempt combine both approaches together for enhances and restores the anticorrosive properties of metallic structure.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; In the present investigation the microcapsules of blended Dehydrated Castor oil and Tung oil in epoxy coating matrix along with Polyaniline nanoprticles have been studied. The addition of PANI into the epoxy coating was studied to observe improving effect of PANI on the epoxy coating matrix [10]. Also it has been already reported that incorporation of microcapsules with healing agent in epoxy coatings has enhances the corrosion protection performance in coating. So, in continuation of the work on corrosion protective coating and considering the literature reports we intended to prepare and investigate self-healable epoxy/PANI nanoparticle/vegetable oil microcapsules composites. It is expected that such type of self healing coating work as good corrosion protective coating.</p> <p>This investigation reports, the successful encapsulation of blend of Tung oil and Dehydrated Castor oil (20 wt. % and 30 wt. % DCO) as self-healing agent. It also explains the preparation of polyaniline (PANI) nanoparticles as corrosion inhibitor. The surface morphology of prepared microcapsules were analyzed initially by digital optical microscope and then with SEM. Whereas, the particle size of synthesized microcapsules and PANI nanoparticles were determined by particle size analyzer and TEM respectively. The core content of the microcapsules was determined by extraction process using soxhlet apparatus. The self-healing properties as well as anticorrosive performance of encapsulated microcapsules in combination with PANI nanoparticles were studied by incorporating them into epoxy coating matrix. Corrosion protection of coated panels were analyzed by immersion in 3.5% NaCl and 0.5 M HCl solution and studied in comparison with pristine epoxy coated panels.</p> U.B. Gawai, P. S . Shisode, P. P. Mahulikar, C. B. Patil Copyright (c) 2021 U.B. Gawai, P. S . Shisode, P. P. Mahulikar, C. B. Patil https://spast.org/techrep/article/view/1565 Sat, 09 Oct 2021 00:00:00 +0000 Development of Heterogeneous catalysts for CO2 fixation under atmospheric pressure in cocatalyst free conditions https://spast.org/techrep/article/view/626 <p>The development of newer pathways to develop cyclic carbonates are gaining importance owing to its widespread applications. Cyclic carbonates are used as high boiling solvents, electrolytes in lithium-ion battery and as the precursors of value-added chemicals like diols, dialkyl carbonates and polyurethane etc [1]. Conventional pathways involve the use of phosgene to prepare cyclic carbonates but the toxic nature of phosgene inspired the chemists to develop greener and eco-friendly methods for the synthesis of cyclic carbonates. In this context the cycloaddition of CO<sub>2</sub> with epoxides to develop cyclic carbonates have gained much attention. The atom economic perspective and the use of CO<sub>2</sub> as the C1 feedstock are the major advantages of this methodology [2]. However, the high thermodynamic stability and kinetic inertness of CO<sub>2</sub> molecule resulted it to have very high activation energy. This is the crucial bottleneck of this reaction which confined CO<sub>2</sub> fixation in high pressure reactors with a combination of both pressure and temperature. Homogeneous catalysts have been developed that has given satisfactory yields in milder conditions but the solubility of these catalysts in reaction mixture hinders their post catalytic separation and further recyclability [3]. Recently much attention has been given for the development of heterogeneous catalysts which can be reused and used for multiple cycle of catalysis thus making them commercially more viable. However, the major setback of the heterogeneous catalysis involves the use of homogenous cocatalysts like ammonium salts to get satisfactory conversions under milder conditions [4]. Hence it is still a major challenge to develop heterogenous catalysts to carryout CO<sub>2</sub> fixation in cocatalyst free conditions under atmospheric pressure.</p> <p>Here heterogeneous catalyst has been developed in which iron is coordinated to ligands possessing triaminoguanidine and catechol units. The catalyst is synthesized through a solvothermal method of the ligand and ferric salts. Iron is the fourth most abundant element on earth crust, non-toxic to environment and relatively very cheap. The reason for choosing nitrogen rich moieties like triaminoguanidine is due to their efficiency in increasing the polarity within the framework. <sup>&nbsp;</sup>The enhanced polarity by the nitrogen rich units is expected to impart stronger interactions with CO<sub>2</sub> molecules for better selective adsorption. The characterization concluded the material to be an water stable amorphous coordination polymer developed through Fe-O bonds through catechol units of the ligand with Fe(III) ions. The as-prepared material was found to be very efficient to convert a of variety of epoxides into their corresponding cyclic carbonates under atmospheric pressure of CO<sub>2</sub>. The reactions were carried out in solvent-free and cocatalyst free conditions. Interestingly, the CO<sub>2 </sub>cycloaddition into epoxide was achieved without the formation of any side products that certified the high selectivity of the catalyst. The deliberate role of Lewis acid site and counter anion was investigated by performing various control experiments by changing the metal centre and counter halide ions. The developed catalyst retained its catalytic activity for six reaction cycles. The study clearly points that the polymeric catalyst developed by combining triaminoguanidium and catechol moieties with Fe is a potential candidate for achieving valuable chemicals from CO<sub>2</sub> at ambient conditions.</p> ANTARIP MITRA Copyright (c) 2021 ANTARIP MITRA https://spast.org/techrep/article/view/626 Thu, 16 Sep 2021 00:00:00 +0000 Microwave Synthesis of Cu-Viologen-MOFs and Their Electrochemical Redox Capabilities https://spast.org/techrep/article/view/1730 <ol> <li><strong> Introduction</strong></li> </ol> <p>Metal-Organic Frameworks (MOFs) are porous hybrid materials consisting of jungle-gym-like assemblies of metals (called connectors) and organic molecules (called linkers). Owing to t their regularly porous structure, their properties can be tuned by post-synthetic modifications, as they are expected to be functionalized for gas adsorption / separation, catalysis, and batteries.[1]</p> <p>Although majority of MOFs are redox inactive due to high ionicity of the metal-organic bonds, there have been a few examples to claim reversible redox reactions by employing redox active constituents such as transition metal nodes and aromatic organic linkers. It certainly deserves to seek for electrochemically active MOFs and understand the rules to make them useful for electrochemical applications.</p> <p>In this study, we synthesized novel MOFs by combination of redox active Cu and viologens. While reversible redox of Cu in a MOF structure has been reported [2], viologens are also well known for their reversible redox reactions. For their connection, Lewis basic carboxylates were introduced as N, N'-bis(2-carboxymethyl)-4,4'-bipyridinium dibromide (CM<sub>2</sub>V) and N, N'-bis(2-carboxyethyl)-4,4'-bipyridinium dichloride (CE<sub>2</sub>V) (Fig. 1). Microwave solvolysis has been employed as a method of synthesis of their MOFs, which were characterized for their redox capabilities.</p> <p>&nbsp;</p> <ol start="2"> <li><strong> Experiment </strong></li> </ol> <p>Copper nitrate trihydrate (600 mg), the bromide salt of CM<sub>2</sub>V, or 100 mg of the chloride salt of CE<sub>2</sub>V were dissolved in 20 ml of methanol and heated by subjecting microwave to obtain the precipitate at 100°C for 30 min. To eliminate unreacted organic ligands, an excess amount of copper source was added. The obtained precipitate was washed several times with methanol and separated in a centrifuge at 3500 rpm, 20 min.</p> <p>After that, the samples were vacuum dried at 70°C for 12 hours to obtain yellow and pale blue powder samples, respectively. The crystal structure and composition of each sample were identified by XRD, TG-DTA, FT-IR, UV-vis, and BET measurements. The redox function was evaluated by electrochemical measurements of the electrodes coated on the FTO substrate with DMF solution dispersed with MOF and PVDF binder.</p> <p>&nbsp;</p> <ol start="3"> <li><strong> Results and discussion </strong></li> </ol> <p>Two types of samples (Cu-CM<sub>2</sub>V-MOF and Cu-CE<sub>2</sub>V-MOF) were isolated from the precursor solution of dissolved copper and various linkers. XRD and SEM showed that Cu-CM<sub>2</sub>V-MOF and Cu-CE<sub>2</sub>V-MOF were crystalline samples with a particle size of about 5 µm and a shape of spherical or plate-like Cu crosslinked by each molecule. From the XRD profile, all the peaks of the prepared samples were different from both copper nitrate and each viologen, and a diffraction peak was observed on the low angle around 10°, which suggests that a compound with a wide interlayer spacing was formed.</p> <p>Furthermore, TG-DTA measurements of each sample showed combustion peaks originating from each organic molecule with 54% and 58% weight loss at around 375°C for Cu-CM<sub>2</sub>V-MOF and 230°C for Cu-CE<sub>2</sub>V-MOF, respectively, indicating that the obtained sample was a composite material consisting of copper and viologen organic ligand.</p> <p>XRD patterns of the sample after calcination of Cu-CM<sub>2</sub>V-mof under air showed the formation of copper (II) bromide, and the weight loss of TG-DTA indicated that the ratio of copper to viologen in the fabricated sample was 1:2.</p> <p>The UV-vis spectra of each samples showed absorption at 279 nm and 273 nm from viologen in Cu-CM<sub>2</sub>V-MOF and Cu-CE<sub>2</sub>V-MOF, respectively, and broad absorption from 600 nm to 800 nm corresponded with the d-d transition of copper, which supports the above results.</p> <p>On the other hand, FT-IR measurements of the CM<sub>2</sub>V and CE<sub>2</sub>V monomers revealed carboxylic acid-derived stretching vibration peaks at 1742 cm<sup>-1</sup> and 1719 cm<sup>-1</sup>, respectively, while these peaks were not observed in the prepared samples. The carbonyl <em>ν</em><sub>as coo-</sub> peaks were observed at 1610 cm<sup>-1</sup> and 1630 cm<sup>-1</sup>, and <em>ν</em><sub>s coo-</sub> peaks at 1414 cm<sup>-1</sup> and 1401 cm<sup>-1</sup>, suggesting that the samples were synthesized by bridging copper atoms with viologen.</p> <p>The BET surface areas of Cu-CM<sub>2</sub>V-MOF and Cu-CE<sub>2</sub>V-MOF were measured to be 24.46 and 11.12 (m<sup>2</sup>/g), respectively, while the crystal sizes were micro-ordered, suggesting that the samples were porous MOFs.</p> <p>When the prepared MOF electrodes were immersed in 0.5 M KCl solution, the Cu-CE<sub>2</sub>V-MOF electrode faded and dissolved, while the Cu-CM<sub>2</sub>V-MOF electrode did not dissolve. &nbsp;Therefore, we focused on the Cu-CM<sub>2</sub>V-MOF electrode to evaluate its redox function by cyclic voltammetry (Fig. 2).</p> <p>The potential range of -0.85 V ~ +0.5 V (vs. Ag/AgCl) was measured for 300 cycles at a sweep rate of 50 mV/s. The redox behaviour assumed as the first reduced species of CM2V described as CM2V ⇄ CM2V- + e-(E1/2 = -0.61 V vs. Ag/AgCl) was observed up to 150 cycles. The redox behaviours expected as Cu0 ⇄Cu+ +e- (E1/2 = -0.21 V vs. Ag/AgCl) and Cu+ ⇄Cu2+ +e- (E1/2 = +0.23 V vs. Ag/AgCl) were appeared gradually, and the redox currents decreased from around 250 to 300 cycles. At the 150th cycle, when the peak currents of viologen and copper reached their maximum, the reversibility ratio derived from the ratio of the total reduction current to oxidation current was estimated to be more than 90%. The redox activity ratio, which is the ratio of the theoretical active amount of MOFs on the electrode to the amount of chemical species involved in the actual oxidation reaction, was estimated to be 1.3% at the maximum (150 cycles). It is clear that only the MOF particles grounded on the FTO electrode surface could reversibly redox.</p> <p>These results indicate that the redox of viologen MOFs originating from the connector and linker, respectively, can occur within the same structure. Although there is still a lot of issues for improvement in the electrical connection of the dead MOFs on the electrode, we believe that elucidating the details of the redox mechanism will lead to the development of batteries.</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> YUJI HIRAI, Hiroto Yamaguchi, Erika Saito, Satoshi Chubachi, Tensho Nakamura, Tsukasa Yoshida Copyright (c) 2021 YUJI HIRAI, Hiroto Yamaguchi, Erika Saito, Satoshi Chubachi, Tensho Nakamura, Tsukasa Yoshida https://spast.org/techrep/article/view/1730 Sat, 09 Oct 2021 00:00:00 +0000 Effect of annealing temperature on the structural and optical properties of the 2D-layers of Sn-Se alloy https://spast.org/techrep/article/view/2815 <p>Thin film solar cells have drawn researchers’ attention due to their low manufacturing cost, ease of manufacturing and less material consumption in comparison to the conventional silicon solar cells [1]. Tin-based binary chalcogenide compounds Sn-X (X; = S, Se, Se<sub>2</sub>, Te) have gathered global attention due to their abundance, low environmental impact besides their potential applications in the electronic, optical, optoelectronic devices and flexible systems [2]. Tin diselenide (SnSe<sub>2</sub>) and Tin monoselenide (SnSe) belongs to the A<sup>IV </sup>B2<sup>VI</sup> family. SnSe has a distorted rock-like structure, whereas SnSe<sub>2 </sub>is a 2D-layered material having 'Sn' sandwiched between 'Se' and occupies a CdI<sub>2</sub> type structure. SnSe<sub>2 </sub>possesses narrow bandgap energy, high absorption coefficient and provide brilliant application prospects as optoelectronic devices, thermoelectric refrigerators, super-capacitors, holographic recording systems, thin film photovoltaic devices and solar cells. Moreover, in case of 2D layers of Sn-Se alloy, only two phases (SnSe/SnSe<sub>2</sub>) were found present thereby avoiding the formation of more phases in Sn-Se alloy as compared to the CISe, CIGSe, and CZTSe compounds [3]. Also lower transmission and higher absorption values have been obtained for thin films consisting of SnSe and SnSe<sub>2</sub> phases as compared with pure SnSe<sub>2</sub> layers [4]. In the present case, powder of Sn-Se alloy was prepared by directly fusing highly pure ‘Sn’ and ‘Se’ (1:2 ratio) elements in an evacuated quartz ampule at 1127<sup>o</sup>C and the ingot so obtained after cooling, was crushed and sieved to obtain Sn-Se alloy powder. The powder so obtained was used as a source material to prepare 250 nm Sn-Se alloy 2D-layers on ultrasonically cleaned corning glass substrate at base pressure of 2x10<sup>-6 </sup>mbar in the vacuum coating unit at 473 K, followed by annealing of the samples in a tubular furnace at the vacuum ~1 x 10<sup>-3</sup> mbar for one hour (h) in each case at temperatures ranging from 473 - 623 K. SnSe<sub>2</sub> phase was identified on the basis of its significant peaks at ‘2θ’values of 14.41(1)<sup>o</sup>, 44.29(1)<sup>o</sup>, and 60.35(2)<sup>o</sup> corresponding to (001), (003),and (004) diffraction planes and as-deposited films show two prominent peaks of SnSe<sub>2</sub> at ‘2θ’ values of 14.37(8)<sup>o</sup> and 30.76(9)<sup>o</sup> corresponding to (001) and&nbsp; (101) diffraction planes of hexagonal crystal system with space group P3m1(164)&nbsp; (JCPDS card No. 23-0602) along with the presence of SnSe phase as shown in Fig 1. The transmission and absorbance spectra of the as-deposited and annealed 2D layers were measured in the wavelength (λ) range 300-1500 nm at room temperature and optical absorption co-efficient (α) of the order of ≥ 1x10<sup>5</sup>cm<sup>-1</sup> has been obtained in all the annealed 2D layers. The direct bandgap (Eg) values found to liebetween 1.34 – 1.60 eV. The morphology of the films was obtained by scanning electron microscopy, while the elemental composition was determined by energy dispersive x-ray analysis (EDAX) are conducted <em>in situ</em> with the SEM. The grain size found to vary between 11.80 - 24.19 nm. The vibrational properties and crystal structure of the films were obtained from Raman spectra of the 2D-layers. The peaks obtained at 76 cm<sup>-1</sup>and 151 cm<sup>-1 </sup>show the modes of SnSe whereas, the peaks obtained at 107 cm<sup>-1</sup>and 187 cm<sup>-1</sup>corresponding to the E<sub>g </sub>mode (in plane vibration) and A<sub>1g </sub>mode (out of plane vibration) respectively confirms the presence of SnSe<sub>2</sub> phase as shown in Fig 2[5].The diffraction pattern suggests that annealed films are the mixture of SnSe and SnSe<sub>2</sub> but dominated by the SnSe<sub>2</sub> phase with preferred orientation along (001) and (101) oriented planes. Improved absorption response has been obtained with crystallite size enhancement after annealing, indicating the use in photoconverters and solar cell applications.</p> NARESH PADHA Copyright (c) 2021 NARESH PADHA https://spast.org/techrep/article/view/2815 Sun, 17 Oct 2021 00:00:00 +0000 An Understanding material chemistry of mobile handset for recycling feasibility analysis https://spast.org/techrep/article/view/718 <p>The last two decades have seen significant change in efficiency and effectiveness at which communication happens. Mobile phones and the smartness associated with them can be attributed to as the single most important factor for such transformation. With volume of mobile handsets sold seeing an increasing trend, emphasis on recycling and waste policy has increased by multifold. Schematic of metal components constituting production of a typical handset and each of the segmented parts has been showcased along with data of waste generation from various states of India. Literature review provides insights on willingness of public to donate the e-waste and frameworks which utilizes multiple stakeholders. This paper discusses the economic viability of metal extraction considering factors such as metal process time, relative effort and general requirement which identifies high extraction efficiency of metal. Comparison chart has been tabulated for each of the metals with regard to expenditure, revenue generated, processing methods and processing difficulty. The results obtained provide satisfactory evidence to further improve the process to enhance the metal extraction</p> Shruthi MN Copyright (c) 2021 Shruthi MN https://spast.org/techrep/article/view/718 Wed, 15 Sep 2021 00:00:00 +0000 Pressure Induced High Conductivity in Mn Doped ZnTiO3 Composite System https://spast.org/techrep/article/view/1897 <p>Among different complex oxides, Zn<sub>2</sub>TiO<sub>4</sub> having an inverse spinel structure is a promising material for its wide range of applications as sensors, and optoelectronic devices [1–3]. On the other hand, the ZnTiO<sub>3</sub> ilmenite structure possesses an indirect bandgap which limits its application in the field of optoelectronics [4]. Many works are reported in these materials on the applicability as dielectric, gas sensors, optoelectronic, and microwave telecommunication devices [2,5,6]. This work emphasizes the possibility of the current generation due to the induced pressure on the Mn-doped ZnTiO<sub>3</sub> systems. This work reports the conversion of ZnTiO<sub>3</sub> structure to Zn<sub>2</sub>TiO<sub>4</sub> using Mn doping at Ti site having Mn percentage of 0%, 12.5%, 25%, and 50% (denoted as S0, S1, S2, and S3 respectively) using modified sol-gel synthesis route. This work gives a detailed understanding of both the ilmenite and inverse spinel structures and their implications on the phonon modes, and optical bandgap. For the first time, the theoretical investigation of the phonon modes of the ilmenite ZnTiO<sub>3</sub> is done using density functional theory (DFT) to understand the phonon dynamics by correlating it with the bond lengths and bond angles. The phonon modes associated with the cationic disorder of the Zn<sub>2</sub>TiO<sub>4</sub> structure are found to be related to the Urbach energy (E<sub>U</sub>) from the optical band gap study. The optical band gap transformed from indirect bandgap to direct bandgap with an increase in the Mn doping percentage. The phase of the prepared samples was confirmed using the Rietveld refinement. The ZnTiO<sub>3</sub> is in the rhombohedral phase having an <em>R-3</em> space group and the Zn<sub>2</sub>TiO<sub>4</sub> is in the cubic phase having an <em>Fd-3m</em> space group. The cell volume of the rhombohedral and cubic structure continuously increased from S0 to S2 due to the presence of a single phase in the prepared samples. But, for the S3 sample, the cell volume was observed to be contracted due to the presence of only a cubic phase [Table 1]. The applicability of the prepared materials was studied using a pressure-dependent I-V characteristics study. A homemade setup was used for the measurement [Fig 1]. At different constant voltages, the current value was recorded by varying the applied pressure on the materials. At a constant voltage of 10 V, the current value increased with an increase in the Mn doping at different applied pressure. This behavior was due to the transformation of phase as well as the optical bandgap in respective materials due to the Mn incorporation. This shows the applicability of the material as pressure sensors. This work achieved a drastic change in a low current value for undoped case (S0) to nearly 40µA with 50% Mn doping (S3) [Fig 1].</p> KOYA SUMAN SAMANTARAY, Prashant Mishra, Mahesh Kumar, E.G RINI, SOMADITYA SEN Copyright (c) 2021 KOYA SUMAN SAMANTARAY, Prashant Mishra, Mahesh Kumar, E.G RINI, SOMADITYA SEN https://spast.org/techrep/article/view/1897 Fri, 08 Oct 2021 00:00:00 +0000 Fabrication strategies for three-dimensional graphene architectures from graphene oxide https://spast.org/techrep/article/view/227 <p>Carbon materials and their allotropes have been involved significantly in our daily lives. 0D C60, one-dimensional (1D) carbon materials, and two-dimensional (2D) graphene materials have distinctive properties and thus received immense attention from the early 2000s [1, 2]. To meet the growing demand for these materials in applications like energy storage, electrochemical catalysis, environmental remediation, etc, the special category i.e. three-dimensional (3D) structures assembled from graphene sheets have been developed. Graphene oxide is a chemically altered graphene, the desired building block for 3D graphene matter (i.e. 3D graphene macrostructures). A simple synthesis route and pore morphologies make 3D reduced-graphene oxide (rGO) a major candidate for the 3D graphene group. To obtain target-specific 3D rGO, its synthesis mechanism plays an important role [3, 4]. Hence, in this article, we will discuss the general mechanism for 3D rGO synthesis, vital procedures for fabricating advanced 3D rGO, and important aspects controlling the growth of 3D rGO.</p> Rasmeet Singh . Copyright (c) 2021 Rasmeet Singh . https://spast.org/techrep/article/view/227 Thu, 09 Sep 2021 00:00:00 +0000 Abstract An Innovative Synergy of Vegetable Oil-based Self-Healing Anticorrosive Coatings: A Collaborative Approach https://spast.org/techrep/article/view/1977 <h1>An Innovative Synergy of Vegetable Oil-based Self-Healing Anticorrosive Coatings: A Collaborative Approach &nbsp;</h1> <p><strong><sup>b</sup></strong><strong>P. S. Shisode; <sup>b</sup>C. B. Patil and P. P. Mahulikar<sup>a</sup></strong>*</p> <p><strong><sup>a </sup></strong>* School of Chemical Sciences, Kavayitri Bahinabai Chaudhari North Maharashtra University, Jalgaon, (M.S), India.</p> <p><sup>b </sup>Department of Chemistry, S. S. V. P. Sanstha’s L. K. P. R. Ghogrey Science College, Deopur, Dhule, (M.S), India.</p> <p>E-mail: *<a href="mailto:mahulikarpp@rediffmail.com">mahulikarpp@rediffmail.com</a>, <a href="mailto:p_shisode@yahoo.co.in">p_shisode@yahoo.co.in</a> and <a href="mailto:cbpatil82@rediffmail.com">cbpatil82@rediffmail.com</a></p> <p><strong>Abstract</strong></p> <p>Corrosion, a natural but adverse electrochemical phenomenon which occurs when metal comes in contact with environment, creates a huge problem as it reduces performance and durability of the metal component and ultimately leads to premature failure, thus, accountable for certain financial losses and technological delays [1-4]. The economic losses can cost about 3-4 % of global gross domestic product (GDP) yearly [5-10].</p> <p>An excellent, easy, fast and cheap way of corrosion protection is the application of barrier coatings. But, coating during its service life is susceptible to damage/ imperfections in coating either by hostile environment or by mechanical stress. Consequently, the corrosion of the metallic substrate will be initiated and accelerated by aggressive species through the deteriorated coating. Conventional techniques for repair of such coatings are patching and welding which are actually limited to visible damages. As these methods are not autonomic, it was essential to find a better tactic to repair the micro cracks [7]. Though, it is impossible to create a perfect coating which would never break, but a novel method of autonomic repair of damage has been achieved through the use of self-healing coatings [9, 10].</p> <p>Through the development of these smart self-healing materials, Suryanarayana <em>et al </em>[15] have developed self-healing coating with microencapsulated linseed oil (drying oil). The drying oil like linseed oil has film forming ability by atmospheric oxidation, Thus, microcrack is get healed autonomically. To perform self-healing function better the vegetable oil or drying oil (healing agent) in the microcapsule should meet the following properties…</p> <ol> <li>It should have high percentage of unsaturation so as to get auto oxidized i.e., should have high iodine value.</li> <li>It should have optimum viscosity so as to flow fast to fill the complete crack.</li> </ol> <p>Among various vegetable oils, the castor oil is the cheap source of triglyceride fatty acid and secondary hydroxyl group with 92-95 % ricinoleic acid [14]. Castor oil is non-drying oil but the dehydrated castor oil can be used as drying oil even better than linseed oil as it is having high gloss, good adhesion and non-yellowing property. But, the kinematic viscosity of dehydrated castor oil is 156-160 centipoises which is actually responsible for reducing its fluidity. In turn Dehydrated Castor Oil is unable to heal the micro-crack completely within fraction of seconds that affects its self-healing ability. In order to avoid such creeping effect of more viscous Dehydrated Castor Oil, it is better to add creep resistant low viscous Soybean Oil [12]. The low viscosity liquid has excellent fluidity that lends them to be a good self-healing agent [6].</p> <p>Relaying on these facts [11-16], herein, a new strategy for smart coatings is presented with enhanced mobility of active ingredient. The self-healing efficiency of more viscous Dehydrated Castor Oil filled microcapsules was improved with addition of less viscous Soybean oil when blended in various combinations. Microcapsules were prepared by in situ polymerization of UF resin to form shell over blended oil droplets. A set of characterization method for synthesised microcapsules was used to confirm their morphology and chemical composition. Thermogravimetric Analyser (TGA) was used to investigate their thermal property. These microcapsules basically exhibit good storage stability at room temperature, and they are chemically stable before the heating up to 200 <sup>0</sup>C approximately. The microcapsules embedded self-healing coatings were fabricated by dispersing the prepared UF microcapsule into epoxy coatings matrix as a topcoat. The self-healing anticorrosion function of these coatings system were evaluated through immersion studies of damaged and healed microcapsules coated steel panels in 5 % NaCl solution.</p> <p>&nbsp;</p> Dr., Professor, Dr. Copyright (c) 2021 Dr., Professor, Dr. https://spast.org/techrep/article/view/1977 Fri, 08 Oct 2021 00:00:00 +0000 Composition assisted bandgap tuning of honey green synthesized Mg-Zn spinel nanoferrite https://spast.org/techrep/article/view/2053 <p>Spinel nanoferrites are represented by AB<sub>2</sub>O<sub>4</sub>, A - divalent metal ions, B–, trivalent metal ions, display face-cantered cubic (fcc) structure with tetrahedrally coordinated A site, octahedrally coordinated B site. They exhibit very interesting magnetic properties as compared to their bulk counterparts, and hence are useful in wide range of applications such as data storage, magnetically guided drug delivery, ferrofluids etc [1]. Green synthesis of ferrites is shown to be an eco-friendly as compared to other popular chemical, and physical methods [2], expected to exhibit lesser toxicity, has potential application in hyperthermia for cancer treatment [3]. Sol gel auto-combustion method, utilizing non-toxic and/or less toxic natural, economical precursors e. g. - honey, aloe vera plant extract, etc., can be efficiently employed to synthesize ferrite nano-particles at relatively low temperatures (~ 200 <sup>o</sup>C), consumes less energy, and thus is more cost effective, and ensures spinel phase formation in dry gel form, where no heat treatment is needed. Spinel nanoferrites with bandgap ~2 eV, have strong absorption in visible-region (~50% of solar-radiation) is advantageous, and would show improved efficiency in photocatalytic applications [4], can be magnetically recovered for re-use, and has shown significant efficiency towards the degradation of organic, inorganic pollutants [5]. Literature [6] reports composition assisted tuning of bandgap, and thus a spinel ferrite having appropriate bandgap can be more effective in photo-catalytic, solar energy related applications. Thus, in this work we report honey green synthesis of Mg<sub>x</sub>Zn<sub>1-x</sub>Fe<sub>2</sub>O<sub>4</sub> (x = 0.0 &nbsp;- 1.0) by sol gel auto-combustion protocol, and impact of successive Mg addition on tuning energy bandgap, probed by x-ray diffraction (XRD), ultraviolet–visible (Uv–Vis) spectroscopy). Samples were prepared by utilizing Nitrate-Acetate pre-cursors, as described in [6], and honey as chetaling agent, fuel, keeping pH 7. Formed dry gel samples were used for characterization without any post-preparation thermal treatment. XRD, Uv-Vis data analysis yields structural parameters, cationic distribution, Néel magnetic moment n<sub>N</sub>, energy bndgap. XRD (fig. 1a) validates the formation of spinel nano ferrite (grain diameter: 28.1 - 38.5 nm). Presence of a-Fe<sub>2</sub>O<sub>3</sub>, is ascribed to absence of thermal annealing. Linear decrease of lattice parameter (fig. 1a inset) is attributed to the addition of Mg<sup>2+</sup> ion with slightly lower ionic radius (0.72 nm) as compared to Zn<sup>2+</sup> ion (0.074 nm). Linear decrease of a<sub>exp.</sub>, described by equation: a<sub>exp.</sub> = 0.84 – 0.005&nbsp; [Mg-content], shows strong correlation between Mg-content and a<sub>exp.</sub> Addition of Mg<sup>2+</sup> ion shows transition from&nbsp; normal to inverse ferrite (fig. 1b), and leads to modification of oxygen parameter ‘<em>u</em>’ (fig. 1b) revealing increase of disorder, and also shows linear decrease of n<sub>N</sub>. Fig. 1(c) reveal weakening of B–O–B super-exchange interaction with simultaneous strengthening of A–O–A, A–O–B interaction, affecting <em>n<sub>N</sub></em>, (see fig. 1 c). With increasing Mg-content, Fe<sup>3+</sup> ion occupation on B-site decreases (affects <em>n<sub>N</sub></em>&nbsp; as seen in inset of fig. 1d ) , with corresponding increase on A-site. Mg<sup>2+</sup>, Zn<sup>2+</sup> ions remains more populated respectively on B-, A-site. Presence&nbsp; &nbsp;of Mg<sup>2+</sup> ions on A, B site &nbsp;&nbsp;shows&nbsp; &nbsp;non- equilibrium &nbsp;&nbsp;cationic distribution as also&nbsp;reported in [7]. Fig 1e shows Mg-content dependent fine–tuning of band gap (between 1.63 V– 1.97 eV), is a collective result of variation of lattice parameter, grain diameter, and cationic distribution as is also seen in [6]. Fig. 1e(inset) shows dependence of bandgap on lattice parameter, showing strong correlation between structural properties, and bandgap. It is of value to note that, compositional dependent tunability of bandgap is valuable in enhancing photocatalytic efficiency. Current study noticeably shows strong relationship between structural properties, cationic distribution, and bandgap.</p> Shashank KANE, Priyanka Copyright (c) 2021 Shashank KANE, Priyanka https://spast.org/techrep/article/view/2053 Fri, 08 Oct 2021 00:00:00 +0000 Cost Optimization and Emission control of a Grid connected Hybrid PV-Wind system for a Health Care Centre in India https://spast.org/techrep/article/view/1398 <p>Due attention is needed for energy demand in health care centers as energy requirement for average Energy Use Intensity (EUI) is huge. It is to be noted that EUI is the energy per square foot per year. The technology advancement result in sophisticated and inevitable equipment, increases the energy consumption of the health care centers. The maintenance of these equipment and increase in the patient to doctor ratio are also one of the main reason which affects the energy consumption. India is found to be the fourth largest greenhouse gasses emitter. As a result, India is much affected by the change in climatic conditions. Therefore the obligatory situation is arised in India to reduce the global warming which can be possible with the penetration of renewable energy based electricity generation. Our major objective is to produce the electrical energy with the optimized PV- wind system and to avoid the global warming with the optimized energy generation technology.</p> <p>The novelty in the work is to generate the electricity with Hybrid pv-wind system for a health care centre in India, and to payback the excess energy produced to the electricity board through grid system.&nbsp;&nbsp;</p> <p>A health care center which uses 160kWh/day of electrical load and deferrable load of 10kWh/d is taken for analysis. 200 kW of PV and 100 kW of wind generation capacity are proposed for generating power. The monthly average wind speed profile and solar profile is downloaded from NASA Prediction of Worldwide Energy Resource database. 300kW converter is used, with the mean output of 38.8W capacity is used in the proposed system for power conversion.An idealized battery storage system of 48V is introduced with the capacity of 139kWh and round trip efficiency of 64%.</p> <p>Homerpro 3.11.2 is used to obtain and analyse the optimization result. The analysis gives best solution for cost summary, economic comparison in using various resources. This microgrid requires 1938 kWh/day and has a peak of 305 kW. In the proposed system, the energy demand, energy selling and cost analysis is done. The energy demand of the health care system is estimated and the remaining energy produced is sold back to the grid. Grid power is connected to the system with simple rates of grid power rate and sell back rates.</p> <p>From the Homer Analysis, the Net Present Value, total Annualized Cost, simple payback, Return on Investment (ROI), the Internal Rate of Return (IRR) and annual savings are estimated for the proposed system. It is estimated that our investment has a payback of 1.33 years and an IRR of 75.3%. The annual energy purchased from the grid is 6,639 kWh and the annual energy sold to the grid is 643,549 kWh.</p> <p>Along with the cost analysis,&nbsp; the emission of gases like carbon dioxide, carbon monoxide, unburned hydrocarbons, particulate matter, sulfur dioxide and nitrogen oxides are also calculated for the proposed system. The analysed result gives null result for the emission of green house gases and the proposed system becomes environmental friendly system in reducing the global warming. Also cost analysis of the proposed system proves the annual savings in regards with the energy consumption.</p> Abitha Memala W Copyright (c) 2021 Abitha Memala W https://spast.org/techrep/article/view/1398 Thu, 07 Oct 2021 00:00:00 +0000 Mineral-inspired approach mediated design, solution synthesis, characterization and luminescence study of blue emitting phosphor BaSc2Si3O10:Eu2+ https://spast.org/techrep/article/view/1432 <p><strong>Abstract </strong></p> <p><strong>&nbsp;</strong>A series of new silicate based luminescence materials, Ba<sub>1-x</sub>Eu<sub>x</sub>Sc<sub>2</sub>Si<sub>3</sub>O<sub>10</sub> (BSS:Eu<sup>2+</sup>) (x = 0.005, 0.01, 0.02, 0.05, 0.07), which can be efficiently excited by UV light and generates a broadband bright blue emission, with ‘Internal Quantum Efficiency’ 45% have been developed from a water-soluble propylene glycol modified silane (PGMS) based silicon precursor by a systematic solution based bottom up approach. The concept as well as the methodology of using a ‘Mineral Inspired Approach’ emerges as a new blueprint for the strategic design of novel phosphors for phosphor converted white light emitting diode (pc-WLEDs) [1-4]. The detailed crystal structure of monoclinic BSS:Eu<sup>2+</sup> was determined from the XRD profile. Steady state photoluminescence measurement as well as the thermal quenching properties of the phosphor has been investigated in detail. The high quantum efficiency of the phosphor owes to the uniform distribution of activator ions into the host matrix which is attributed to the adopted synthesis approach named amorphous metal based complex (AMC) method. It is noteworthy to mention that ‘AMC’ method has several advantages such as the complexation of the cation by citric acid enhancing the stability of the initial solution against hydrolysis or precipitation. The hydrolysis or precipitation results in the increases of the local activator concentration detrimental to the emission intensity of the synthesized phosphor, which is arrested by AMC method resulting in the high quantum efficiency of the phosphor. The optimum concentration of Eu<sup>2+ </sup>in this matrix was found to be 2% and the ‘Concentration Quenching’ mechanism was verified to be the dipole-dipole interaction and the critical distance was calculated to be 25.01 Å. A highly efficient broadband blue emission centred at λ<sub>max</sub> ~ 446 nm shows very low thermal quenching; 71.2% at 150 <sup>o</sup>C with respect to that measured at room temperature. The remarkable thermal stability of the phosphor was attributed to the rigid structural network of the host and weak electron–phonon coupling strength [5-8]. The interesting photoluminescence properties and robust thermal performance reflect the potential application of this phosphor for UV- LED driven solid state lighting.</p> Dr Sudeshna Ray Copyright (c) 2021 Dr Sudeshna Ray https://spast.org/techrep/article/view/1432 Thu, 07 Oct 2021 00:00:00 +0000 Scandium and Niobium incorporated Lithium Titanate as the anode for Li-ion batteries https://spast.org/techrep/article/view/2127 <p>The present study is focused on the modification of lithium titanate (LTO) ceramics by incorporating double dopant Scandium and Niobium to improve the specific capacity and better cycling performance of the electrode of the Li-ion battery. The correlation between the microstructure and the properties of the electrode has also been discussed. &nbsp;and Scandium and Niobium doped Lithium Titanate are prepared by a sol-gel technique based on the formula&nbsp; Li<sub>4-x </sub>Sc<sub>x </sub>Ti<sub>5-y </sub>Nb<sub>y </sub>O<sub>12</sub>, where x = y = 0.0 &amp; 0.3. It has been observed that the Sc and Nb incorporated LTO showing tangible improved properties. The specific capacity of Sc and Nb incorporated LTO has been observed as 170.4 mAhg<sup>-2 </sup>&nbsp;at 1 c, while this value has shown a decrease in the value of specific capacity of the electrode i.e. 114.8 mAhg<sup>-2 </sup>&nbsp;at 5 c even after many test cycles. Thus the Sc and Nb incorporated PTO may be used as high rate anode material. It has also been observed that Nb doping is suitable for the reversible cycle of the battery system and for the better &nbsp;extraction of Li<sup>+</sup>. An attempt to correlate the microstructure and the properties of Sc and Nb-doped LTO &nbsp;has also been done. All the findings indicate that Li4<sub>-x </sub>Sc<sub>x </sub>Ti<sub>5-y </sub>Nb<sub>y </sub>O<sub>12&nbsp; </sub>&nbsp;nanoelectrodes may be a competent anode for a lithium-ion battery. &nbsp;&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> Rohit Kumar Sinha, Shradha Kishore, Amit Kumar Sinha, Sanjay Kumar Sinha Copyright (c) 2021 Rohit Kumar Sinha, Shradha Kishore, Amit Kumar Sinha, Sanjay Kumar Sinha https://spast.org/techrep/article/view/2127 Fri, 08 Oct 2021 00:00:00 +0000 a Intrinsic Strength Behaviour of RAC subjected Elevated Temperature https://spast.org/techrep/article/view/2199 <p>Increased construction and development activities have contributed to the economical growth of the nation increasing the GDP value [1]. This increased constructional activity has boomed the requirement construction materials and also increase in&nbsp; construction and demolition of waste (C &amp; D) materials. Managing the requirement of useful resources and overcoming the hurdle of increased quantum of C &amp; D waste is the biggest challenge faced by the today’s society. In this study an effort is made to consider C &amp; D waste as a partial replacement of coarse aggregate to arrive at recycled aggregate concrete and emphasize on their strength properties. From the studies that has been carried out on concrete made by using C &amp; D waste it is suggested that recycled coarse aggregates (RCA) needs to be studied carefully and study its characteristic which provides the inference about <br>specific gravity, water absorption and their strength. Hence characterization of RCA is an important aspect that provides dimension to the study carried out on RAC. Studies were carried to emphasize on using RAC as structural concrete to maximize the benefits of using RCA and reducing the burden of requirement of natural resources. While RCA are being used as structural concrete, there is a possibility of concrete being exposed to elevated temperature, due to which concrete gets disintegrated. Hence through understanding needs to be arrived at strength behaviour of RAC and then observe its strength properties at <br>elevated temperature. Strength properties of RAC are affected by amount of adhered mortar that are attached to the RCA [2], that can be beneficial to RAC when subjected to elevated temperature. Aggregates that are siliceous in nature exhibits loss in strength at 300̊C and undergo crystallization at 575̊C with sufficient increase in volume causing deterioration of concrete [3].Carbonate aggregates like lime stone and dolomite exhibit thermal stability up to 700̊C. Hence the deterioration of concrete is strongly&nbsp; attributed to the miss match in the thermal expansion properties of aggregate and cement paste resulting in thermally induced <br>stresses in the interface transition zone (ITZ) between the aggregate and cement paste. If the tensile stresses exceeds the tensile strength of cement paste, then radial cracks originates at the adjacent transition zones [4]. Hence choice of aggregates is the prime factor while concrete are considered at elevated temperature. Hence after careful investigation of RCA, RAC are prepared by considering RCA as partial replacement of natural coarse aggregates and study the behaviour at elevated temperature. In this study an effort is made to understand the behaviour of recycled aggregate concrete (RAC) by considering replacement ratio of 0%, 50% and 100% and w/b ratio of 0.27 and 0.36 for compressive strength, split tensile strength and its flexural strength. Behaviour of RAC is studied for elevated temperature; TGA analysis and FTIR are conducted on the RAC that is <br>arrived by conducting optimization. From the results of the study conducted we can predicted the behaviour of RAC subjected to elevated temperature and from the TGA and FTIR analysis the beneficiated RAC can be proposed as a structural concrete at elevated temperature.</p> B.Suguna Rao Copyright (c) 2021 B.Suguna Rao https://spast.org/techrep/article/view/2199 Thu, 07 Oct 2021 00:00:00 +0000 Portable lateral flow assay for sensitive detection of tetracycline based on metal enhanced fluorescence https://spast.org/techrep/article/view/608 <p>&nbsp;Lateral flow assays (LFAs) have found comprehensive applications especially in disease diagnosis, environmental detection, and food safety. The accumulation of tetracycline (TET) in water has raised serious concerns on the health of human beings. The sensitive detection of TET in drinking water is urgent. The present detection of TET mainly relies on high performance liquid chromatography (HPLC), microbiological methods, chemiluminescence, capillary electrophoresis (CE), electroanalysis, colorimetric analysis, which has obvious disadvantages of low sensitivity and selectivity, high cost, complex operation and nonportable for offsite use. In this study, a sensitive and portable near infrared LFA has been developed based on plasmonic resonance enhanced fluorescence for the detection of TET. By optimizing the sample volume, the incubation time, the volume of buffer solution and the concentration of tween20 in the buffer solution etc., a low detection of limit (LOD) of 0.1 ng mL<sup>−1</sup> is achieved with fast and portable readout. The improved sensitivity is originated from the plasmonic resonance of gold nanostar core which can significantly enhance the fluorescence of the dye molecules through an ultrathin SiO<sub>2</sub> shell. The near infrared fluorescence features with deep penetration and low background noise, which also contribute to the high sensitivity. The present LFA shows great potential applications in environmental protection by quantitative detection of an</p> Xiuyun Niu Copyright (c) 2021 Xiuyun Niu https://spast.org/techrep/article/view/608 Thu, 16 Sep 2021 00:00:00 +0000 Dr MOHD TAAZEEM ANSARI Modification of structural and electron transport properties of zigzag nano graphene transistor for myriad electronic applications https://spast.org/techrep/article/view/1708 <p>Electron transport has been studied theoretically through a modeled device comprising of a smallest <br>(4-atoms wide) zigzag graphene nanoribbon (ZGNR) as channel coupled to symmetric (8-atoms wide) <br>ZGNR as electrodes within the limelight of nonequilibrium green’s function formalism (NEGF) conjoined <br>with density functional theory (DFT) incorporated into a set of phyton-based computational codes <br>termed as ATK VNL. The doped device in forward and reverse bias mode shows multiple striking NDR <br>feature within the applied bias 0.0-2.0 V, starting with the appearance of first sharp NDR at very low <br>voltage range 0.0-0.7 V. Doping of the pristine device with nitrogen/boron atoms results in n-type/p-type <br>form acting as a root for pouring the device with several useful striking features such as logic, memory, <br>oscillations, switching, amplification, rectification, etc. The repercussion of Doping is switching from the <br>symmetric current trend to asymmetric which sets the stage for the device to act as rectifier evident by <br>sorting the maximum magnitude of rectification ratio (R) and peak to valley ratio (PVR) which is <br>approximately 38 and 5 respectively. Negative differential resistance (NDR), an important feature <br>of interest in the nano-electronic devices is the prime focus of this study. The appearance of NDR is <br>essential for the implication of the present device in electronic based applications such as switching, <br>rectification, logic and. The modelled structure of boron (B) doped (p-type), nitrogen (N) doped (n-type) <br>and simultaneously B/N doped device alongside with their I-V characteristic are delineated in this study.<br>However, for the sole purpose of short description, only p-type doped device shown and discussed here<br>due to generation of fascinating properties among the three. The considered boron doped device shown <br>in Fig. 1(a) is only 3.5 nm long with transmission channel being 1/5th of it. Thus, rendering it to be a <br>smallest nanodevice that can be fabricated for consumer electronics. Consequently, the I-V <br>characteristics confirms promising instant switching for the device in Fig. 1(a’) with zero delay in the <br>forward and reverse bias mode (possibly due to negligible charge carrier storage time). Thus, it can be <br>considered as miniaturized fast switch faster than tunnel diode due to ceased ballistic mode of transport <br>at nano scale as quantum mechanical effects comes into play</p> MOHD TAAZEEM ANSARI Copyright (c) 2021 MOHD TAAZEEM ANSARI https://spast.org/techrep/article/view/1708 Fri, 08 Oct 2021 00:00:00 +0000 Facile synthesis of high aspect ratio gold coated magnetic nanowires https://spast.org/techrep/article/view/739 <p>Magnetic nanoparticles are of immense importance in various biological applications such as bio-imaging techniques, drug delivery, hematologic disease detection, biomolecules separation (Figure 1). However, one of the limitations faced while using magnetic nanoparticles is to synthesize small size, high surface to volume ratio particles via simple approach. Magnetic nanoparticles in general are synthesized using hydrothermal method, template based method or electrochemical methods. These conventional synthesis approaches are not only complex to carry out but are also time consuming. Herein, we report a wet chemical method to synthesize high aspect ratio magnetite (Fe<sub>3</sub>O<sub>4</sub>) nanowires. The benefit of this method is facile, rapid and cost-effective process. The method involves a chemical reduction of ferrous sulphate and ferric chloride. The resultant product was obtained in two portions – the precipitate and the supernatant. Physical appearance of both the precipitate and supernatant was observed as brown in colour. These synthesized magnetic nanoparticles in supernatant were light in weight and completely dispersible in water for more than 6h. Surface morphology analysis of these nanoparticles demonstrated that the precipitate was aggregate of nanoparticles whereas the particles present in the supernatant were observed to be thin nanowires of dimension approximately ranged from 200 to 275nm with calculated aspect ratio of approximately eleven (Figure 2). Magnetic property was observed in these nanowires using a simple bar magnet. &nbsp;Further, to enhance its biocompatibility, a thin gold coating was carried out on its surface. A reaction was performed by citrate capping followed by reduction using sodium borohydride in presence of chloroauric acid[1]. Gold coating was confirmed by a UV-vis absorbance spectrum that showed a distinct plasmonic peak at 540 nm (Figure 3). The prospective application planned in this study is for efficient separation of exosomes from bodily fluids. Conventionally exosome isolation is challenging in terms of process complexity, cost and accuracy[2]. Gold coated magnetic nanowires will allow direct attachment of a large number of exosomes by affinity interactions which can significantly enhance the capture efficiency. The magnetic activity allows magnetic nanowire based mixing, separation and purification via magnetic isolation and purification steps[3]. Alongside the light weight and dispersible nature of these nanowires prevents their agglomeration in the cell suspension allowing easy separation after exosome attachment using the external magnetic field. Overall these as synthesized high aspect ratio magnetic nanowires can be used as highly efficient nanocarriers for direct isolation of bulk exosomes from bodily fluids via magnetic separation method and thus can avoid the use of expensive commercial kit based multi-step pre-extraction procedures.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <img src="https://spast.org/public/site/images/pankhi/mceclip0.png"></p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Figure 1. Applications of magnetic nanoparticles</p> <p>&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <img src="https://spast.org/public/site/images/pankhi/mceclip1.png">&nbsp; &nbsp; &nbsp; &nbsp; <img src="https://spast.org/public/site/images/pankhi/mceclip2.png">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</p> <p>Figure 2. SEM image of nanowires&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Figure 3. Absorption spectra of gold coated nanowires</p> Pankhi Singh, Sourav Kumar Kajli, Somnath C Roy, Sudeep Bose, Ranu Nayak Copyright (c) 2021 Pankhi Singh, Sourav Kumar Kajli, Somnath C Roy, Sudeep Bose, Ranu Nayak https://spast.org/techrep/article/view/739 Wed, 15 Sep 2021 00:00:00 +0000 Fabrication of SnS & SnS2 two-dimensional (2D) heterojunctions and its device applications https://spast.org/techrep/article/view/955 <p>Cost effective synthesis of future generation energy storage &amp; optoelectronic devices with nature friendly materials is a challenge. Hence, we come up with some non-conventional fabrication techniques of highly crystalline 2D tin (Sn) chalcogenides namely (SnS &amp; SnS<sub>2</sub>). These Sn based 2D materials with their Earth abundancy, nontoxicity &amp; environmentally friendly nature are suitable for some sustainable electronic applications.</p> <p>SnS<sub>2</sub>, a Sn based 2D material isoelectronic with graphene[1] belongs to a class of 2D Layered metal dichalcogenides (LMDs). Unlike other LMDs like WS<sub>2 </sub>&amp; MoS<sub>2,</sub> both the bulk &amp; single layer SnS<sub>2</sub> possess indirect band gap[2],[3].&nbsp; It is a n-type semiconducting material&nbsp;with an indirect band-gap of 2.2 - 2.35 eV. SnS<sub>2 </sub>with hexagonal crystal structure has unique characteristics including high carrier mobility[4], fast photo response[5], good photo catalytical activities &amp; high optical absorption[6]. Lateral or vertical heterostructure of SnS<sub>2</sub> with graphene[7],[8] or other 2D materials has many potential applications such as high charge storage capacity, stability, electrodes with long life for ion batteries. Whereas SnS which is one of the polytype of SnS<sub>2</sub> is a p-type semiconductor with an orthorhombic crystal structure. SnS is also an indirect bandgap semiconductor with a band gap of 1.08 -1.74 eV. SnS can be considered as a good candidate for solar cell applications as its band gap is near to an optimum value of 1.5 eV for maximum solar radiation absorption. SnS<sub>2</sub> is a promising candidate for lithium/sodium ion batteries, solar cells, sensors, photodetector, field effect transistor applications[9],[10]. Despite its unique optoelectronic applications, SnS<sub>2 </sub>has been rarely studied.</p> <p>Here our main objective is to fabricate SnS<sub>2 </sub>using various deposition techniques like physical vapor deposition (PVD), chemical vapor deposition (CVD) and device fabrication with hetero stacking of other 2D materials. We co-evaporate Sn with S in CVD which is a bottom-up approach, schematic is shown in figure (1a). Hetero stacking can be done in CVD by choosing the required precursors &amp; by monitoring the growth parameters. We also take different 2D materials as substrates to grow SnS<sub>2</sub> thin films directly onto them, which is hetero stacking of layers. Among more than 70 polytypes of SnS<sub>2</sub> here we aim at obtaining SnS &amp; 2H-SnS<sub>2 </sub>with Suitable growth conditions in CVD. A p-n junction is made by the lateral or vertical hetero stacking of SnS, SnS<sub>2</sub>. Here we use Sn thin film instead of bulk Sn by thermally evaporating bulk Sn into few layers Sn film using thermal evaporation unit which is a PVD technique, as shown in figure (1b). The physical as well as chemical properties of the formed SnS<sub>2</sub> layers were studied with multiple characterization techniques. The techniques including X-ray diffraction (XRD), Glancing incidence X-ray diffraction GIXRD, Transmission electron microscopy (TEM), Scanning electron microscopy (SEM), Atomic force microscopy (AFM), X-Ray photoelectron spectroscopy (XPS), Photoluminescence (PL) &amp; Raman spectroscopy are used to characterize film structure, orientation, morphology, composition, optical bandgap of SnS<sub>2</sub> film. Our synthesis methods &amp; experimental findings may lead to future directions &amp; opportunities for the optoelectronic &amp; energy storage device applications of 2D materials family.</p> Sai Lakshmi Janga Copyright (c) 2021 Sai Lakshmi Janga https://spast.org/techrep/article/view/955 Sat, 18 Sep 2021 00:00:00 +0000 Chemistry and Applications of Organosilanes – An Overview https://spast.org/techrep/article/view/1451 <p>Organofunctional silanes are hybrid materials of silanes and have attracted greater attention in recent times owing to its versatile properties and wider range of applications. Organosilanes (R<sub>n</sub>SiX<sub>4-n</sub>) usually have two reactive groups, viz. organofunctional groups like methacryloxy, epoxy ,amino or sulfo group (-R<sub>n</sub>) and hydrolysable alkoxy such as methoxy/ethoxy/acetoxy groups (-X<sub>4-n</sub>) (<strong>Table.1</strong>) [1]. Hydrolysis and condensation are the two main reactions carried out by the molecules of organofunctional trialkoxy silanes. In hydrolysis, hydrolysable alkoxy groups are hydrolysed to silanols (Si-OH) and condensation takes place among silanols to form Si-O-Si (siloxane) structure. Ref. [2] has extensively dealt with silane coupling agents (SCA) used in reinforced polymeric composites (RPC). In general, inorganic fillers particles are used in RPC, in which case, the organic polymer and inorganic filler are two dissimilar materials and hence not compatible with each other leading to substrate adherence issues in coating applications. This problem can be solved by using a third material, i.e. SCA which can connect between organic polymer and inorganic filler by means of the different functional groups present in its structure. Ref. [3] deals with the reaction kinetics of silanes to address the drawback that sometimes, silanes are synthesized without comprehending the reaction kinetics mechanism. The authors in that paper have discussed the alkoxysilanes polymerization kinetics, which is controlled by primary (water/silane ratio, pH and organo-functional groups) and secondary (temperature, solvent, leaving group and silane concentration) factors, and their influence on the reaction rates. In the past few decades, significant advances were witnessed in the development of various organofunctional silanes which were used in a wide range of research areas based on its bifunctional characteristics. In this mini-review, we have summarized the unique chemistry of organosilanes and highlighted their innumerable applications (<strong>Fig.1</strong>) including coupling agents, adhesion promoters, cross linkers, fillers,&nbsp; modifying agents, sensors, nanoparticles and catalysts [3-5]. This work was supported by CSIR, Government of India under CSIR-EMR-II scheme (03(1450)18/EMR-II dt.05-06-2018). A.A.P also thank VIT for providing ‘VIT SEED GRANT’ for carrying out this research work.</p> <p><img src="https://spast.org/public/site/images/indu2019/fig.-1a-uploaded-image.jpg" alt="" width="992" height="221"></p> B.INDUMATHY, Gunasekhar R, Sathiyanathan P, Anand Prabu Arun Copyright (c) 2021 B.INDUMATHY, Gunasekhar R, Sathiyanathan P, Anand Prabu Arun https://spast.org/techrep/article/view/1451 Thu, 07 Oct 2021 00:00:00 +0000 A study on effect of laser texturing on wear and hardness of Nickel aluminum bronze https://spast.org/techrep/article/view/509 <p>Laser surface texturing was carried out on Nickel aluminum bronze material with dimple pattern using nanosecond laser to investigate the effect of laser parameters like Power, scanning speed, Hatch spacing, Frequency on Quality Characteristics of the texture such as Depth of the texture, Average roughness (Ra), Root mean square (Rq) and Maximum height of the profile (Rt). Experimental layout was designed using Taguchi L8 array to understand the influence of parameters on Depth, Ra, Rq, Rt of the texture. ANOVA was performed to find out the influencing weightage factor for depth, Ra, Rq and Rt of the texture. From wear analysis it was found that volume loss, deformation of the pin was lower for textured compared to untextured specimen. The enhanced wear performance in textured specimen is &nbsp;because texturing offers a lower contact area between pin and disc, also texturing&nbsp; improves the hardness of the surface when compared with untextured surface.</p> Keshav M, Rajkumar G R, Bharatish A, Pavan G Copyright (c) 2021 Keshav M, Rajkumar G R, Bharatish A, Pavan G https://spast.org/techrep/article/view/509 Wed, 15 Sep 2021 00:00:00 +0000 Dielectric and piezoelectric properties of hybrid microwave low temperature sintered KBT for LTCC applications https://spast.org/techrep/article/view/2733 <p>Piezoelectric ceramics are essential components of the electronic industry as actuators, phase shifters, sensors etc. Lead-free potassium bismuth titanate K<sub>0.5</sub>Bi<sub>0.5</sub>TiO<sub>3</sub> (KBT) ceramic is synthesized by the solid-state double sintering method. The hybrid microwave sintering (HMS) technique is used to sinter the ceramics at a low sintering temperature of 920<sup>o</sup>C. Because of the technological challenges in manufacturing this chemical composition, the number of papers on KBT is relatively limited. The high volatility of the potassium and bismuth components at high sintering temperatures is thought to be the primary cause of poor sinterability and secondary-phase development during KBT in conventional synthesis, but in the HMS have no chance of volatility of the potassium and bismuth due to rapid firing and low sintering temperature compared to conventional sintering. An attempt is made to synthesize KBT at low sintering temperature by hybrid microwave sintering to be employed in low temperature ceramic cofiring (LTCC) technique. The effect of hybrid microwave sintering on KBT samples is investigated from different characterizations. Low sintering temperature attributes to small grains, good morphology which enhances the ferroelectric, piezoelectric and dielectric properties of the ceramics. The dielectric studies confirm the high dielectric constant, and low losses compare to conventional sintering. The XRD studies confirm the tetragonal crystal structure. From the ferroelectric hysteresis studies, the present work reports a soft ferroelectric material that can be easily polarized and depolarized at low fields. Similarly, KBT sintered at 920<sup>o</sup>C resulted in a high transition temperature of nearly 400<sup>o</sup>C compare to the barium titanate family. The large transition temperature is essential in view of device fabrication.</p> <p>&nbsp;</p> <p>&nbsp;<em>Keywords</em>:&nbsp; Hybrid microwave sintering; piezoelectric ceramic; low temperature ceramic co-firing (LTCC); Ferroelectric hysteresis;</p> Madhuri Wullupuri Copyright (c) 2021 Madhuri Wullupuri https://spast.org/techrep/article/view/2733 Thu, 21 Oct 2021 00:00:00 +0000 A compresensive Review on Bioinspired Body Armor Materials https://spast.org/techrep/article/view/2830 <p>Body armor is the clothing worn by army and police personnel to protect against gunfire. Considering its importance, scientists and engineers are working towards the development of body armor materials. There are several countries including India which have increased their military budget and invested a lot in armor-related research. Earlier leather, wood, etc were used as armor materials. With technological advancement metals, ceramics, and composites based body armors are being developed [1]. As one of the key functions of armor is to prevent penetrating threats and internal damage to bodies, materials that exhibit the distinct ballistic energy absorption property are selected. Those materials should also be lightweight so that they cannot hinder the mobility of a person. Drawbacks associated with armors made up of metals and their alloy-based materials are of high density which makes them heavy and offers less protection. In this paper, we will elucidate about the appositeness of bioinspired materials for armor which after experimentation has proven to be more reliable than the present armor materials. &nbsp;&nbsp;</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;One such bioinspired material is Nacre, also known as the mother of pearl. The armor made from this material has the potential to resist the penetration and provide ballistic properties because of having a two-layer of ceramic which is a part of the zig-zag formation of multi-layer polygonal tablets [2-3]. This zig-zag formation mitigates the damage through the crack bridging effect. This bridge act as a reinforcement which leads to an increase in the stiffness and the strength of the nacre. Conch, fish scales, crustancean, cortical bone, etc are also some of the bioinspired structures which are well suited for military armor systems [3]. To control the catastrophic damage and the crack propagation, at the macroscopic level in the conch shell, three layers are seen to be assembled from plywood-like planks [3]. The outermost layer channelizes the crack and the second layer deflects at &nbsp;and the third shows the elastic behavior which absorbs the energy leading to an increase in the toughness of the system. Another extraordinary bioinspired materials are fish scales which have a two-layer flexible configuration, one is embedded and also elastic to absorb the energy and the other one is exposed with the bony layer to prevent the perforation [3]. In this review, the study the energy absorbing mechanism, material properties and reoccurring structural design elements and how they behave under different loading conditions such as tension, bending, compression, shear and indentation will be discussed. There are many artificial techniques like additive manufacturing and 3D printing to develop the general hierarchal and specific design elements present such as a sandwich, tubule, layered, structured and gradient [4]. In nature, there are some biological structures present in materials that have their unique architecture to combat the impacts generated during collisions. So accordingly, the design of armor can be modified optimally as per the requirement. For example, sandwich and tubular structures absorb a significant amount of energy and transfer the energy through elastic deformation, get collapsed and then rebound to their original shapes [4].</p> Prakhar Sharma Copyright (c) 2021 Prakhar Sharma https://spast.org/techrep/article/view/2830 Sun, 17 Oct 2021 00:00:00 +0000 Wide band-gap and piezo-based power electronics for a sustainable future: A brief review https://spast.org/techrep/article/view/760 <p>Sources of the renewable energy system and transportation electrification are proven to be the panacea of supporting sustainable development and countering the issues of climate change. Power electronics equipment, being the integrated part of any renewable energy system or any electrified transport systems (ETS), such as Electric Vehicles, are of prime importance as the overall system efficiency can be improved by focusing on the efficiency of power electronics equipment [1]. With time, new features are being added in ETS and loads are also increasing in renewable energy systems, making the electrical burden increase continuously. Silicon (Si), after ruling in the power electronics market for decades, has reached a saturation level [2]. And to fulfill the requirements of a higher power level, silicon is not a befitting candidate. In such a perspective, wide band-gap (WBG) devices have emerged as an alternate player which has drawn the attention of the power electronics market. As the name suggests, WBG devices (such as Gallium Nitride (GaN) and Silicon carbide (SiC)) have wide band-gap energy and high breakdown voltage, which make them suitable for high power application. Moreover, these devices have lower on-state resistance, better thermal performance, lower output capacitance, and higher frequency than Si-based devices [3]. Because of such special features of WBG devices, these can be used to make the power electronics equipment more efficient, of higher power density, and smaller size.</p> <p>Another such material that helps the power electronics converters to be of higher efficiency, higher power density, lighter weight, and smaller volume is a piezoelectric material. Conventional magnetic energy storage components are the main hindrance to miniaturize power electronics [4]. In this context, piezoelectric-based energy storage techniques (such as piezoelectric transformers) give an alternative to power converters for energy storage. Piezo-based converters are promising for lightweight and miniature power electronics, which can be used in sectors like healthcare and information technology. Additionally, this also gives an option for soft switching and we don’t require other energy store components in such converters.</p> <p>In this article, both the WBG devices and piezoelectric for power electronics applications have been investigated and reviewed based on their various characteristics, advantages, and challenges. This review also serves as an article to find out the research gap in this field.</p> Mohit Bhardwaj, param; Dr. Samina Copyright (c) 2021 Mohit Bhardwaj, param; Dr. Samina https://spast.org/techrep/article/view/760 Wed, 15 Sep 2021 00:00:00 +0000 Dispersive Soil Stabilization using Biopolymers, Bioenzymes, Additives as a Subgrade Material https://spast.org/techrep/article/view/2497 <p>The overall performance of pavement is dependent on the subgrade soil type and its properties. Soil stabilization has always been a substantial concern in construction of</p> <p>highways. In situ soil remoulding is an essential criterion to enhance the fundamental</p> <p>engineering properties of subgrade and to meet the standards of road construction. Various</p> <p>stabilization techniques are utilized to annihilate the inadequate properties of sub-grade soils.</p> <p>Principally, traditionally used soil stabilizers like lime, cement, bitumen etc. and</p> <p>combinations of these have been utilized widely to enhance the properties of problematic soil.</p> <p>These traditionally soil stabilizers are uneconomical and use of gravel or sand to enrich soil</p> <p>properties are depleting. This scenario has led to lots of researches in order to identify and</p> <p>introduce cost efficient and eco-friendly materials, in particular, different types of inorganic</p> <p>to organic stabilizers have been experimented at laboratory level and also in field level in</p> <p>order to scrutinize their suitability as soil stabilizer. This paper elaborates the various research</p> <p>conducted on enhancing sub-grade of the road by stabilizing dispersive soil with</p> <p>biopolymers, bioenzymes and additives. These stabilizers are environmentally friendly and</p> <p>cost-effective alternative to traditionally soil stabilizers.</p> Mallikarjun H Copyright (c) 2021 Mallikarjun H https://spast.org/techrep/article/view/2497 Sun, 17 Oct 2021 00:00:00 +0000 Analysis of Foundation Using GEO 5 Software https://spast.org/techrep/article/view/1895 <p>The foundation of a structure is the component that connects it to the ground and transfers load from the structure to the earth. Foundations are classified as shallow and deep. In this analysis, Shallow foundation is considered. The analysis is to estimate and calculate the factor of safety using GEO5 student version Software. GEO5 Software is a geotechnical program that is used to construct and verify spread footing foundations using input parameters. A vertical and horizontal bearing capacity analysis is performed by the program. Design of Foundation includes four types of foundation. They are Centric Spread Footing, Eccentric Spread Footing, Circular Spread Footing, Strip Footing. Analysis of foundation include different cases like with and without earthquake, with and without surcharge. Main objective of analysis is to design and calculate the dimensions and stability of spread footing foundation and to find the value of factor of safety using GEO5 program. The present analysis looks into how four different types of foundations might increase their bearing capability. In comparison to other types of footing, the results demonstrate that bearing capacity increases greatly in the circular spread footing and decreases in the strip footing.</p> NAYAN M R, Vinod B R, Shobha R, Srushti S, Sneha V P, Panduranga M K Copyright (c) 2021 NAYAN M R, Vinod B R, Shobha R, Srushti S, Sneha V P, Panduranga M K https://spast.org/techrep/article/view/1895 Fri, 08 Oct 2021 00:00:00 +0000 HPMC BASED GASTRO RETENTIVE DRUG DELIVERY SYSTEM OF EFFERVESCENT GUIFENESINE TABLET FOR DRY COUGH https://spast.org/techrep/article/view/1166 <p>Recent advances in Novel Drug Delivery System is aim to enhance safety and efficacy of drug molecule by formulating a convenient dosage form for administration and to achieve better patient compliance. The controlled release drug delivery systems (CDDS) owning the Capacity to be engaged in the stomach remain entitled as Gastro Retentive Drug Delivery Systems (GRDDSs) [1]. One of the novel approaches for better patient compliance is floating drug delivery [2]. Number of gastroretentive dosage forms has been designed to prolong gastric residence time. They enable oral therapy by drugs with a narrow absorption window in the upper part of the gastrointestinal tract or drugs with a poor stability in the colon. Furthermore, the drug can act locally within the stomach and prolonged intimate contact with the absorbing membrane increases efficacy. Challenges for this work are increased variability among dosage units, toxicity due to dose dumping/local irritation, and more rapid development of tolerance. Need for additional patient education and counseling. We are trying to overcome less gastric retention time and trying to reduce the dosing frequency. Gastroretentive systems can remain in the gastric region for several hours and hence significantly prolong the gastric residence time of drugs [3]. Present study involves preperation of floating tablet of Guifenesine with HPMC K10 and K15M floating tablet were designed to achieve the extended release or retention in GIT which may result enhance in absorbtion and leads to increase in Bioavaibility. Enhanced floatability and its retention time in GIT directly enhance Bioavaibility of drug and decrease the frequency of administration of drug [3-4]. The aim of present work is to develop safe, effective Floating drug delivery system for Guaifenesin and an investigation of floating drug delivery systems with an extended release profile. Very first time we are going to formulate floating Guifenesine tablet for dry cough. Guaiphenesin may be commonly used as an expectorant in both productive and non-productive coughs it is especially useful in the treatment of dry, Non-productive coughs which tend to injure the respiratory mucous membranes and bigger picture of this work is frequency of dosing is reduced by formulating controlled release Guifenesine tablet[9]. The main objective of proposed work is to formulate the dosage form that will remain in vicinity of the absorption site for a prolonged period of time and to improve bioavailability of drugs [7]. Following objectives can also be accomplished with present investigation. Release of drug in specific targeted site at specific pH, to avoid the dose dumping, to reduce the frequency of dosing, to achieve improved economy of product [8, 10]. It enhances patient compliance so beneficial for society. The present work showed that promising controlled-release floating matrix tablets of Guaiphenesin were successfully formulated by effervescent technique</p> SUCHITA G. WAGHMARE Copyright (c) 2021 SUCHITA G. WAGHMARE https://spast.org/techrep/article/view/1166 Fri, 24 Sep 2021 00:00:00 +0000 Design, Solution Synthesis, Characterization and Photoluminescence study of a Near-ultraviolet Converting Cyan Emitting NaBaScSi2O7:Eu2+ Phosphor for White LEDs https://spast.org/techrep/article/view/1580 <p>The advent of 21st century has been coined as the age of solid-state photonics because compact and rugged solid-state lamps based on light emitting diodes (LEDs) are replacing conventional fluorescent lamps [1]. This replacement promises an enormous decrease in power consumption, with vast economic and ecological consequences. White light LEDs (WLEDs) represent a promising next-generation illumination source, because of their merits of a long operation lifetime, energy saving capabilities and high material stability [2]. The phosphor converted light emitting diode (pc-LEDs) combine a GaN -based LED with down converting phosphor and emits light in the visible spectral&nbsp;&nbsp; region [3]. The combination of luminescence from the phosphor excited by LED and emission from the LED generate white light [4]. One strategy to make LEDs by coating a near-ultraviolet (n-UV) emitting LED chip (380–420 nm) with a mixture of blue, green and red emitting phosphors, which exhibits smoother spectral distribution over the whole visible range and therefore can obtain high quality white light [5]. Undoubtedly, phosphors play a crucial role for governing the color characteristics of white LEDs including color rendering in the lighting and color reproduction in the backlight. The eventual performance of white LED-based devices strongly depends on the luminescence properties of the phosphors used, as a consequence, research on new phosphors excitable by blue or n-UV light is rapidly increasing and has become one of the most fascinating research topics in the phosphor community [6] To facilitate the next generation of White Light Emitting Diodes (WLEDs) with higher color rendering and warm lighting, the development of inorganic phosphor for efficient conversion of photons from blue/ n-UV light to other visible wavelengths is essential. In this regard, we demonstrate a systematic, cost effective, solution-processable, easily scalable and fully controllable synthesis a new cyan emitting scandium silicate based phosphor NaBaScSi<sub>2</sub>O<sub>7</sub>:Eu<sup>2+</sup> with 86% internal quantum efficiency under <em>n</em>-UV excitation. The concept as well as the methodology of using a “Mineral Inspired Approach” emerges as a new blueprint for the rational design of novel phosphor for phosphor converted WLEDs. Impact of synthesis methodology on the optimization of photoluminescence emission intensity of NaBaScSi<sub>2</sub>O<sub>7</sub>:Eu<sup>2+</sup> phosphor has also been studied and reported. The results evidence the importance of the synthesized phosphor for phosphor converted WLEDs industry.</p> Dr. Prachi Tadge, Dr. Sudeshna Ray Copyright (c) 2021 Dr. Prachi Tadge, Dr. Sudeshna Ray https://spast.org/techrep/article/view/1580 Fri, 08 Oct 2021 00:00:00 +0000 Molecular scale lamellar structure control in comb-shaped random copolymers https://spast.org/techrep/article/view/1622 <p>Block copolymers, which consist of two homopolymers with different chemical properties tethered together formed unique self-assembled structure such as lamellae, cylinder, sphere etc. by microphase separation between each block. It has been experimentally and theoretically revealed that the phase behavior of diblock copolymers depended of χ×<em>N</em> and φ, where χ is the Flory–Huggins segmental interaction parameter, <em>N</em> the degree of polymerization and φ<em><sub>1</sub></em> the volume fraction of one block.<sup>1-4</sup> On the other hand, recently, we and other groups reported that homopolymers and random copolymers also formed a self-assembled structure by phase separation. We have reported that homo and random copolymers of poly(alkyl acrylamide) and poly(alkyl acrylate) formed a highly oriented lamellar structure by annealing under humid condition. It has been concluded that segregation between water adsorbed main chain and alkyl side chains (nanophase separation) is the driving force for the lamellar structure formation. Terashima et al. reported that random copolymer of octadecyl acrylate with oligo ethylene glycol formed a lamellar structure by phase separation between crystalized octadecyl chains and oligo ethylene glycol chains. Furthermore, Nagno et al., has reported order of mesogen in side chain liquid crystal polymer increase with addition of non-mesogenic comonomer. They concluded that segregation between the mesogenic and non-messogenic groups Indeed, we have reported addition of hydrophilic comonomer to the alkyl acrylamide . These reported works indicate that self-assembled structure can be formed even in random copolymers by segregation between main chain and side chain and/or comonomers. The main chain of random copolymer formed the lamellar plane whereas the side chains orient perpendicularly to the lamellar plane. Thus, two types of lamellar structure; alkyl side chains oriented both direction to the main chain (homo lamellar) or that orient one direction and other comonomer orient to the other (hetero lamellar). In this paper, we reported that the homo and hetero lamellar depended on the ratio of comonomer. Moreover, order to order transition; hetero to homo lamellar was demonstrated by changing the annealing condition. The present result suggested that self-assembled structure of random copolymer also depended on φ of comonomer. &nbsp;&nbsp;In this lamellar structure two types of lamellar structure can be formed from random copolymer; homo and hetero segregated lamellar.</p> <p><img src="https://spast.org/public/site/images/kyokyomaro117/mceclip0.png"></p> Mao Kikuchi, Jun Matsui, Nozomi Saito, Shusaku Nagano Copyright (c) 2021 Mao Kikuchi, Jun Matsui, Nozomi Saito, Shusaku Nagano https://spast.org/techrep/article/view/1622 Fri, 08 Oct 2021 00:00:00 +0000 A comparative analysis of structural, optical and electrical properties of polyaniline/ferrite (Co, Ni, Cu, Zn) composites https://spast.org/techrep/article/view/1800 <p>&nbsp;&nbsp;&nbsp; &nbsp;Conducting polymers nanocomposites are proving to be useful materials as they are flexible as well as conducting with large surface to volume ratio[1,2]. Ferrites have supplementary properties with respect to polymers such as they are robust and magnetic in nature. Among the conducting polymers, Polyaniline commonly called PANI, is one of the most widely studied material hence its composite with &nbsp;ferrites will result in a new class of smart material [3]. In this study, PANI, PANI/Cobalt ferrite, PANI/Nickel ferrite, PANI/Copper ferrite and PANI/Zinc ferrite composites were studied. Polyaniline and their composites with ferrites (Co, Ni, Cu, Zn) were prepared via chemical oxidation polymerization method (Fig 1.). Ferrites were synthesized through co-precipitation method by using oleic acid to keep their size in nanometre range. The structural, optical and electric properties of fabricated materials have probed in detail. Structural properties were investigated using X-Ray diffraction spectroscopy (XRD) and Fourier Transform Infrared spectroscopy (FTIR) respectively. Pure ferrites were found to be of crystalline nature, whereas composites are found to be semi crystalline in nature [4]. Scanning electron microscope (SEM) analysis confirmed the formation of all the synthesized composites. The optical band gap of ferrites was calculated by UV-Vis spectroscopy (UV-Vis), is minimum for cobalt ferrite (1.1 eV) and increases for Ni (1.4 eV), Cu (1.3 eV) and Zn (1.9 eV) ferrites. The optical band gap of composites is reducing as compared to Pure PANI (1.7 eV), which is in agreement with already reported work [5]. The inclusions of ferrites particles have caused an enhancement in electrical conductivity of pure PANI [6]. Conduction mechanism observed from Nyquist plots of composites is found to involve both grain as well as grain boundaries. Among all the fabricated materials, different morphology of PANI/Cobalt ferrite composite is attributed in better conduction. The transition metal spinel ferrites have enhanced the optical and electric properties of PANI to a great extent, making them promising materials for different applications.</p> <p><img src="https://spast.org/public/site/images/swati_sehrawat/chemical-oxidation.jpg" alt="Synthesis of PANI/Ferrite composites via chemical oxidation polymerization" width="802" height="526"></p> <p><strong>Fig.1. </strong>Synthesis of Pani/Ferrite composites via chemical oxidation polymerization.</p> Swati Copyright (c) 2021 Swati https://spast.org/techrep/article/view/1800 Sat, 09 Oct 2021 00:00:00 +0000 A Synthesis of Molybdenum Trioxide and their applications. https://spast.org/techrep/article/view/952 <p>After the introduction of graphene, two-dimensional (2D) materials turned into very interesting topics for research because of their excellent electronic, chemical, and mechanical properties [1]. Like other two-dimensional (2D) materials, Transition-metal oxides (TMOs) can be stacked as heterostructures for 2D electronics [2]. Transition metal oxides contain a massive family of materials that performance a variety of extraordinary properties that are attractive for many applications [3]. Transition metal oxides (TMOs) such as MoO<sub>3</sub> have been researched for so many years due to their stunning applications in electronics, gas sensors, Light-emitting diode&nbsp; (LEDs), photo, electrochromic materials, and so on. In this work, we have carried out two types of synthesis on nanostructures of molybdenum trioxides. Molybdenum trioxide (MoO<sub>3</sub>) can be appeared in varied crystal structures like orthorhombic (α-MoO<sub>3</sub>), monoclinic (β- MoO<sub>3</sub>) and hexagonal (h- MoO<sub>3</sub>). When compared with other phases, Orthorhombic (α-MoO<sub>3</sub>) is more stable thermodynamically also maintains a unique layered structure and in each of its layers, the octahedra MoO<sub>6</sub> consists of two sub-layers interconnected in (101) direction [4]. β- MoO<sub>3</sub> is the metastable phase that is transformed into the α-phase by heating above 673K. The unit cell parameters of α- MoO<sub>3</sub> a=0.37 nm, b=0.36 nm, c=1.229 nm (α=β=δ=90<sup>0</sup>) and for β-MoO<sub>3</sub> is a=0.77 nm, b=0.74 nm, c=1.09 nm (α=β= 90<sup>0</sup>, δ=120<sup>0</sup>) [5]. We can use a hot plate and chemical vapor deposition. This method will give multilayers of MoO<sub>3</sub> on graphene/SiO<sub>2</sub> and graphene/glass as a substrate with temperature variations. Hot plate and Chemical vapor deposition (CVD) can be done in ambient conditions.</p> <p>&nbsp;</p> <p>The chemical vapor deposition (CARBOLITE GERO 30-3000<sup>0</sup>C) was utilized to grow α-MoO<sub>3</sub>. The deposited Mo thin films on Sputtering are used as a source and place graphene/SiO<sub>2</sub> as a substrate upside down to source in Quartz tube. The detailed information of tube is 1m length and inner diameter 5.5 cm and outer diameter 5.9 cm containing 0.2 cm thickness of tube in the furnace. We have three zones in CVD, in that three zones, the middle zone has gas flow parameters of Argon (Ar), Oxygen (O<sub>2</sub>), Carbon dioxide (CO<sub>2</sub>), Nitrogen (N<sub>2</sub>). First, MoO<sub>3</sub> form on the source and become like α-MoO<sub>3</sub>. Later α-MoO<sub>3</sub> will be evaporated from temp 650<sup>0</sup>C. Fig.1 shows the arrangement of the source and substrate in a quartz tube, and how it forms on the substrate in CVD. Argon and Oxygen gases pursuing with 1L/min and 2L/min held for 30mins at 650<sup>0</sup>C. We get α-MoO<sub>3</sub> nanosheets on Substrate.</p> <p>&nbsp;</p> <p>An alternate method to grow α-MoO<sub>3</sub> is a hotplate. (iStir HP 550<sup>0</sup>C) was utilized to grow α-MoO<sub>3</sub>. In this case, also, we have used the sputter-deposited Mo film as the source of Molybdenum. It was observed that the Hotplate method produced a large area and faster growth compared to CVD-grown samples.</p> <p>&nbsp;</p> <p>The characterization of α-MoO<sub>3</sub> was studied in X-ray diffraction (XRD), Glancing incidence &nbsp;X-ray diffraction (GIXRD), UV-VIS bandgap, Raman spectroscopy, Impedance spectroscopy, Transmission electron microscopy (TEM), Scanning electron microscopy (SEM), Atomic force microscopy (AFM), X-Ray photoelectron spectroscopy (XPS), may give the information of crystal structure, impedance, orientation, surface morphology, bandgap and optical images of α-MoO<sub>3</sub>. Our synthesis method can also be generalized to other transition metal oxides (WO<sub>3</sub>) for future flexible electronic devices.</p> kalyan kurapati Copyright (c) 2021 kalyan kurapati https://spast.org/techrep/article/view/952 Sat, 18 Sep 2021 00:00:00 +0000 Influence of mixers on dry dispersion of nanoparticles in the cementitious composites https://spast.org/techrep/article/view/319 <p>Nanomaterials are gaining prominence in industries such as construction and medicine. Several parameters like durability and early strength development can be enhanced through the incorporation of nanomaterials into cementitious composites. The major challenge is to achieve uniform dispersion of nanomaterials within the composite’s matrix. Research on the dry dispersion of nanomaterials is in the nascent stage and hence a comparison does not exist between colloidal/wet dispersion and dry dispersion of nanomaterials. Often it is quite difficult to carry out dispersion experiments as it involves different types of expensive mixers and nanomaterials. Also, under experimental conditions, it is very difficult to assess the behavior of the particles during the dispersion process and is considered a research gap. Recently the use of high-performance computing to simulate the mixing of cohesive/non-cohesive materials using the discrete element method (DEM) has opened up as a new field of research in particulate technology. Fan et.al [1] have proved that the DEM can be successfully adopted to simulate particle mixing. This paper concentrates on the interdisciplinary research work that combines concrete technology, nanotechnology, and particulate technology to achieve uniform dispersion of nano-silica (NS) in cement that forms a binary mixture. The nanopowder acts as the active ingredient and the cement acts as the medium of dispersion.</p> <p>In this research work, DEM-based software EDEM was used to simulate the dry mixing of NS with cement in a Conical Mixer and a Mortar Mixer. The main objective of this simulation is to study the impact of the type of mixer on content uniformity. To be more specific, the influence of mixing patterns, dead zones, and the blade of the mixer on achieving content uniformity is studied. Segregation Index (SI) is used to determine content uniformity. SI is a function of time and ratio of particle number in a binary particulate system for different particle sizes [13].</p> <p>The content uniformity depends on many factors such as transferring of the material into the mixer, the actual mixing, discharge of the mix from the mixer, transportation of the materials, storage of the mix, etc. along with the type of the mixer. The various stages of mixing the two types of mixers are depicted in figures 1 and 2. The interaction-less area between the circumference of the bottom of the mixer and blade is known as dead zone and similar zones were observed at many places in the mixer depending on the type of the mixer by Krenzer et al. [2,3] in the study of the behavior of wet mixing of concrete in the Mortar Mixer. Due to the presence of such zones, the uniformity of the mix and degree of mixing is poor as shown in Fig. 2 (c).</p> <p>&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</p> <p>Unlike mortar mixers, the efficiency of mixing is mainly attributed to the influence of helical shaped screw in the Conical Mixer which results in the repeated cyclic flow pattern and three-dimensional particle flow in the mixer. As a result, there are no dead zones in the Conical Mixer. The type of mixer plays a predominant role and thus optimization of the mixing process in achieving content uniformity.</p> Ujwal Shreenag Meda, Bhavana B, Radhakrishna Copyright (c) 2021 Ujwal Shreenag Meda, Bhavana B, Radhakrishna https://spast.org/techrep/article/view/319 Tue, 14 Sep 2021 00:00:00 +0000 Properties of Geopolymer Concrete with Fly Ash and GGBS as Source Material: Effect of Mixture Composition https://spast.org/techrep/article/view/2031 <p>The worldwide utilization of cement is second just to water. As the interest and demand for concrete as a building material increments, so additionally the attention for the OPC. Concrete production is estimated to have increased by 1.5 billion. From 1995 to 2.2 billion. In 2010 (with an increase of 3% per annum). One ton of cement production emits one ton of CO2 into the air. Among the harmful effects of ozone, CO2 contributes 65% to global warming, which contributes to climate change. In addition, cement is the strongest material for construction. It has been accounted that durability of OPC is under assessment as many structures particularly those inherent destructive conditions begin to fall apart following 20 to 30 years, despite the fact that they have intented for over 50 years of service life.</p> <p>Efforts are needed to develop environmentally friendly building materials to reduce greenhouse gas emissions. Geopolymer concrete is a new material with Portland cement as a binder, fly ash, GGBFS enriched with silicon and aluminum, and an alkaline liquid binder. Rigorous testing and error handling have been used to develop fly ash geopolymer concrete technology. The study is aimed at Characterization of Geopolymer concrete by SEM, XRD and FTR. determining the key parameters such as compressive strength, split tensile strength, flexural strength and study the performance qualities from durability consideration including NDT testing such as RCPT, Acid resistance, Rebound hammer, UPV and corrosion analyzer</p> Prashant Sunagar Copyright (c) 2021 Prashant Sunagar https://spast.org/techrep/article/view/2031 Sat, 09 Oct 2021 00:00:00 +0000 The Graphitic Carbon Nitride (g-C3N4): A promising material for photocatalytic CO2 reduction https://spast.org/techrep/article/view/2069 <p>The documented worldwide CO<sub>2 </sub>level in 2019 is 409.8 ± 0.1 ppm and reached 414 ppm in 2020. The CO<sub>2</sub> emission has reached over 35 billion tons per year with 15% hike in the last era only [1-3]. The global consumption of CO<sub>2</sub> is predicted to escalate momentarily which is 0.3 to 0.7 GT per year. To reduce the CO<sub>2</sub> concentrations to recommended safe level (350 ppm), a number of novel techniques have been proposed for arrest of CO<sub>2</sub>, conversion, and storage. Among different state-of-art CO<sub>2</sub> reduction techniques, the green energy forces like photo, electric, bio derived energy are prominent [4-6]. Artificial photocatalytic CO<sub>2</sub> reduction is a fascinating system to harness clean, renewable and safe solar energy to convert into chemical energy. To synthesize a suitable catalyst for photocatalytic reduction of CO<sub>2</sub> is challenging to entire scientific fraternity [7]. Among the catalytic materials selected for photocatalytic reduction, semiconductors based on graphenic materials and graphitic carbon nitride (g-C<sub>3</sub>N<sub>4</sub>) is emerged as the promising semiconductor for photocatalytic applications. These are mainly made up of tris-s-triazine (s-heptazine, C<sub>6</sub>N<sub>7</sub>) units linked with nitrogen atoms to produce a 2D graphitic structure [8-10]. These materials have acquired substantial attention due to its fascinating optical, electrical, physical and chemical characteristics. The constant recurrence of heptazine units facilitates band gap of 2.7 eV along with E<sub>CB</sub> = -1.1 eV and E<sub>VB</sub>= +1.6 eV and reduces it capability of arresting CO<sub>2 </sub>with the aid of sunlight. Till date g-C<sub>3</sub>N<sub>4</sub> has explored its path on the photocatalytic reduction of CO<sub>2</sub>. Mao et al. used g-C<sub>3</sub>N<sub>4 </sub>for reduction of CO<sub>2</sub> to CH<sub>3</sub>OH and C<sub>2</sub>H<sub>5</sub>OH in 2013 using photocatalysis route [19]. They have tested with two precursors: one with urea and the second one is melamine. g-C<sub>3</sub>N<sub>4</sub> prepared through urea showed the best result on alteration of CO<sub>2</sub> to CH<sub>3</sub>OH (6.28 µmol g<sup>-1</sup> h<sup>-1</sup>) and C<sub>2</sub>H<sub>5</sub>OH (4.51 µmol g<sup>-1</sup> h<sup>-1</sup>). Porous nitrogen rich g-C<sub>3</sub>N<sub>4</sub> nanotube was fabricated by Zhao and his group for photocatalytic reduction of CO<sub>2</sub> to CO. Increased surface area and Lewis basicity of porous g-C<sub>3</sub>N<sub>4</sub> increases the adsorption cite for CO<sub>2</sub> and consequently augments the photocatalytic reduction efficiency of CO<sub>2</sub> to 103 µmol g<sup>-1</sup>h<sup>-1</sup>in comparisom to bulk g-C<sub>3</sub>N<sub>4</sub> [11]. A schematic representation of removal of CO<sub>2</sub> through g-C<sub>3</sub>N<sub>4</sub> is given below. Last but not least, this review article summarizes invigorative perspective on the challenges and future direction towards the development of sustainability without environmental detriment.</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> Manasranjan Pradhan, Binita Nanda Copyright (c) 2021 Manasranjan Pradhan, Binita Nanda https://spast.org/techrep/article/view/2069 Fri, 08 Oct 2021 00:00:00 +0000 Biocompatible Gelucire mediated Heterometallic nanohybrids for augmented plasmon-coupled fluorescence emission with graphene oxide https://spast.org/techrep/article/view/434 <p>While the nanoparticles (NPs) sustain localized surface plasmon resonance (LSPR) metal thin films sustain propagating surface plasmons known as surface plasmon polaritons (SPPs) (here polariton is the coupled oscillation of the incident radiation and the surface plasmon) [1]. Coupling of excited fluorophores with the SPPs sustained in metal the thin film aids in the realization of sharply directional and highly polarized (p-polarized) emission known as surface plasmon-coupled emission (SPCE) [1]. Lackowicz and co-workers in their pioneering approach synergistically combined both metal-enhanced fluorescence (MEF) and SPCE into a single platform to realize 60-fold fluorescence enhancements [2]. Further, in recent times different nanohybrids with silver (Ag) as the primary plasmonic material has been explored in SPCE [3]. Gold (Au) NPs have not been extensively explored despite their multifunctional properties such as top-notch stability, excellent biocompatibility and exceptional ease in biochemical functionalization and tunable optoelectronic performance in visible &amp; NIR optical regions. The central cause for this is the huge inter-band Ohmic losses consequential in quenching of the fluorescence emission. The coupling of luminescent moieties to higher-order plasmonic modes give rise to inefficient non-radiative pathways [4], leading to quenching.</p> <p>Different approaches for dequenching the signal in the presence of AuNPs have been experimentally and theoretically demonstrated in the recent times. Some of them include use of: (i) core-shell metal structures, (ii) anisotropic NPs sustaining pointed tips, (iii) AuNP decorated on dielectric NPs, (iv) nanogaps in assemblies harboring gap-based nano-antennas sustaining intense hotspots [4]. Despite various approaches that have been undertaken hitherto, the SPCE enhancements obtained through these strategies remain &lt; 200-fold [4,5]. Thus the need for nanoarchitectures that sustain intense three-dimensional hotspots have gained prominence recently for the realization of not only dequenched, but also augmented SPCE enhancements. In our previous report [4], we observed that the heterometallic nanohybrids synthesized <em>via</em> novel routes provided an important edge over the utility of their individual counter-parts. Conventionally, achieving sharp nanostructures for MEF is possible using toxic reducing and capping agents that are hazardous for the environment and the ecosystem as a whole. In this background, the call for sustainable research is the need of the hour [6]. Therefore, the focus has been shifted towards green nanotechnology which emphasizes developing methodology that promotes the use of sustainable and eco-friendly materials for obtaining nanomaterials [6,7]. Taking this factor into consideration, there is compelling need to reconsider the exploration of plasmonic sensor development from an eco-friendly, biocompatible and sustainable point of view.</p> <p>Gelucire® has a wide variety of application in oral and topical formulations for drugs such as meloxicam (used for treatment of arthritis), clotrimazole (used for treatment of antifungal infections) and so on. Gelucire® finds extensive application, in enhancing the solubility and bioavailability of drugs. It aids in sustained drug release as well as in stabilization of tropical formulations, consequently helping in the superior penetration of the drug through skin. Though extensively used as a solubility enhancer in the field of pharmaceuticals by virtue of its biocompatibility, this work is the first of its kind wherein gelucire® has been used in AgNPs, AuNPs, AgAu nanohybrid synthesis, more so for plasmonic application. Using a frugal one-pot synthesis methodology involving UV exposure, nanohybrids with tunable optoelectronic properties have been synthesized. Interesting structural morphology such as pointed anisotropic geometries were obtained which resulted in electromagnetic hotspots, thereby dequenching of emission in the presence of AuNPs. The synthesized nanohybrids have been studied in SPCE platform with additional graphene oxide monolayer to realize &gt; 1400-fold highly p-polarized and directional emission enhancements, pushing the sensitivity limits of biosensing frameworks to much lower concentrations. The sensing study was performed using a cost-effective smartphone-based setup. This technique significantly simplifies the conventional sensing techniques and make it amiable for resource-limited settings. On account of the biocompatibility of the synthesized NPs we believe that this methodology would find widespread applications in different research fields. Especially in the point-of-care diagnostics it could prove to be helpful for rapid detection of various biomarkers for numerous diseases.</p> Aayush Rai, Seemesh Bhaskar, Kalathur Mohan Ganesh, Sai Sathish Ramamurthy Copyright (c) 2021 Aayush Rai, Seemesh Bhaskar, Kalathur Mohan Ganesh, Sai Sathish Ramamurthy https://spast.org/techrep/article/view/434 Wed, 15 Sep 2021 00:00:00 +0000 A State-of-the-art review on Antimicrobial Textiles for Military Applications https://spast.org/techrep/article/view/2143 <p>Biological warfare&nbsp;is the deliberate use of disease-causing&nbsp;biological agents, the so called ‘bio-weapons’ such as bacteria, virus and fungi, or their toxins, to kill or incapacitate humans, animals, or plants as an act of war [1]. Coatings of natural antimicrobial agents on the textiles are being used since ancient times, when the Egyptians used spices and herbal coatings on cloths to fabricate the mummy wrap. Traditionally, bamboo fibers, which contained an antimicrobial compound called ‘Bamboo-kun’ for housing structure, were used by ancient Chinese people. The research on bamboo fibers have also been carried out owing to their natural antibacterial and antifungal properties, which are mediated by 2–6-dimethoxy-p-benzoquinone and dendrocin [2]. In order to protect the fabric from microbial colonization and enhancing their durability, military fabrics were treated with antimony salts, copper and a mixture of chlorinated waxes, which not only stiffened the fabrics but also gave them a distinct odor. Antimicrobial Textile (AMT) is the best option for military personnel to combat the bio-weapons. AMT have inherent property for killing bacteria and virus.</p> <p>AMT can be prepared by using antimicrobial technologies integrated with textiles by either encapsulation or by impregnating it in woven fibers [3]. These antimicrobials agents are metal nanoparticles or metals salts such as Silver [4], copper [5], polyhexamethylene biguanide (PHMB) [6]. These metal salts are found to be much effective compared to iodine based antimicrobial agents since the metal-based antimicrobials leads to absolute bacterial inhabitation whereas in the iodine based formulations, there is possibility of bacterial regrowth. Silver is pretty suitable for socks fiber of military as it completely inhibits odor and stop <em>E. coli</em> which is quite prone to develop in foot. The strong antimicrobial impact of silver essentially increases its pote[ntial to be used in antimicrobial fabric. The green boot socks issued to Soldiers from the SCIE Defense Logistics Agency (DLA) are one of the known currently fielded items to incorporate antimicrobial properties into the textiles, using 99.9% Ag<sup>+</sup>-lining in the nylon. It is important to mention here that health hazard analysis (HHA) was also carried out by the Army’s Public Health Command (PHC) in 2008 before the product was distributed, which ensured that there was no safety concern. On the other hand, Triclosan is a compound that is active against bacteria, molds, and yeast by blocking the synthesis of lipids and it can be applied directly to textiles as a surface coating or by encapsulation. PHMB is another broad-spectrum biocide active against bacteria and fungi and due to its versatility, PHMB is commonly used in wound dressings and for infection control and potentially be used as a finish on cotton, wool, and cotton/wool blends to make the fabric antimicrobial in nature. Copper oxide impregnated fibers found to exhibit substantial antimicrobial properties [7].</p> <p>In this comprehensive review, we elucidate the state-of-the-art review of the antimicrobial fabric to combat bio-weapons. We also discuss the challenges and the future prospects of these fibers for biological warfare.</p> Dr Sudeshna Ray Copyright (c) 2021 Dr Sudeshna Ray https://spast.org/techrep/article/view/2143 Fri, 08 Oct 2021 00:00:00 +0000 Synthesis of Aromatic Hyperbranched Polymer based on Diphenolic Acid and Pentaerythritol: Reaction Kinetics using FTIR technique https://spast.org/techrep/article/view/2731 <p>Hyper branched polymers (HBPs) are an important class of materials which have generated much interest among researchers owing to their unique properties such as highly-branched architecture, diverse functionalities and easier synthetic processes with applications ranging from biomaterials, nanocomposites, optoelectronics, polymer coatings, to name a few [1,2]. However, the challenge is to synthesis the HBPs with well-defined architecture using readily available monomers. In general, HBPs can be polymerized by one-pot process from AB<sub>n</sub> type monomers, A<sub>2</sub> + B<sub>n</sub> (n ≥ 3) type monomer pairs, and so on [1]. In this study, we report the sequential melt-polycondensation method synthesis of aromatic HBP. <strong>Fig. 1(a)</strong> shows the aromatic HBP based on diphenolic acid as monomer (AB<sub>2</sub> type) and pentaerythritol (A<sub>4</sub> type) as core molecule using para-toluene sulphonic acid as the catalyst in the presence of DMSO solvent. <strong>Fig. 1(b)</strong> shows the reaction kinetics of the HBP-Gen 1 synthesis using FTIR analysis of samples withdrawn at regular intervals of time. The shift in FTIR peak corresponding to acid from 1684 cm<sup>-1</sup> to ester peak at 1720 cm<sup>-1</sup> confirms the formation of HBP and it could be observed that maximum conversion was achieved at around &nbsp;8 h reaction time<strong>. </strong><strong>Acknowledgement:</strong> This work was supported by CSIR, Government of India under CSIR-EMR-II scheme (03(1450)18/EMR-II dt.05-06-2018).</p> <p><img src="https://spast.org/public/site/images/gunasekhar8383/mceclip0.png" width="828" height="402"></p> R. Gunasekhar, Dr., Dr., Anand Prabu Arun Copyright (c) 2021 R. Gunasekhar, Dr., Dr., Anand Prabu Arun https://spast.org/techrep/article/view/2731 Thu, 21 Oct 2021 00:00:00 +0000 Mechanical and characterization behavior of light weight aggregate concrete using sintered fly ash aggregates and synthetic fibres https://spast.org/techrep/article/view/139 <p>This study focuses on the usage of sintered fly ash aggregate in the production of lightweight concrete. To minimize the environmental impacts, would alleviate the waste disposal issues related to fly ash and contribute to the decrease of environmental pollution. Construction materials are in high need in the domestic sector, which is growing increasingly rare day by day. In India, the power sector is currently reliant on thermal power plants, which generate a massive amount of fly ash, estimated to be roughly 200 million tonnes each year. Fly ash is a waste product produced by thermal power stations when pulverized coal is burned. The use of industrial waste as a building material is a significant step toward long-term sustainability. In addition, the mechanical characteristics of sintered fly ash aggregates were discussed. According to the results, the specific gravity of these aggregates is 16–46% lower than that of regular weight aggregates, and they have higher water absorption. The 28-day compressive strengths of sintered fly ash aggregate concrete range from 27 to 74 MPa, with densities ranging from 1651 to 2017 kg/m<sup>3</sup>. According to the study, sintered fly ash aggregate concrete is also one of the materials that might be used to develop structural concrete. Sintered fly ash aggregate was used to replace natural aggregate (12%). The compressive, tensile, and flexural strengths of concrete produced with natural aggregate and sintered fly ash aggregate were compared. Also, Concretes were conducted to a microstructure test and an SEM analysis. This shows that concrete incorporating sintered fly ash aggregate can be produced with properties equivalent to natural aggregate concrete.</p> ramasubramani r Copyright (c) 2021 ramasubramani r https://spast.org/techrep/article/view/139 Thu, 02 Sep 2021 00:00:00 +0000 Light weight body armour using coconut fibre composite material https://spast.org/techrep/article/view/899 <p>This research work focuses on indigenous raw material and technology to partly solve the<br>soldiers’ problems in the warfront. Efficient low-cost material and more durable might be a<br>relevant economical advantage.[1] Coconut fibre also acts as an insulator protecting the<br>soldiers from extreme climatic conditions Analysis is done to assess its suitability for the<br>armour for the soldiers. The composite material contains of coconut fibre along with oil for<br>impregnation. The complete set of body armour of a soldier weighs 15 Kgs and along with all<br>the sophisticated equipment it becomes a cumbersome job for any soldier to sustain military<br>operations for a longer period of time. When the insurgency is at the rise, soldiers must be<br>well equipped, and the kit weighs slightly less at almost 12.5 kg along with at least 22.5 kg in<br>additional gear– which might be acceptable for a cargo truck driver but certainly not for an<br>infantryman patrolling on foot in the extreme heat of middle east battle fields or guarding the<br>borders of India in sub-freezing temperatures. There is actual evidence to support decrements<br>in performance and survivability due to the increasing load our soldiers have to carry, because<br>as much as they need protection from bullets and impoverished explosive devices, they also<br>need to be able to manoeuvre the battlefield quickly. Sacrificing speed and agility for protection<br>is the major trade-off of our modern armour systems. It would be certainly better if a soldier<br>has the same level of protection with 1/3rd the amount of load with lesser cost and more<br>durability [2]. And that’s where this solution comes handy. Coconut fibre is available in<br>enormous quantity in India. This fibre along with a few other materials when used as a part of<br>light weight body armour helps in solving two critical issues namely safety of the soldiers and<br>enhanced income to the farmers. Natural fibres composites have recently been investigated<br>as possible alternatives for Kevlar.</p> Vincent Wilson Copyright (c) 2021 Vincent Wilson https://spast.org/techrep/article/view/899 Sun, 17 Oct 2021 00:00:00 +0000 Experimental Study of Bearing Capacity Bridge Foundation Determination https://spast.org/techrep/article/view/1200 <p>Ethiopia is almost mountainous and hilly in topography, with many rivers flowing from the cities' centres. To facilitate transportation, a bridge across the Berbere Wonze River must be built. The bearing capacity of foundation soil is important for foundation design because it can carry heavy loads from the superstructure. The primary goal of this experimental geotechnical investigation is to determine the bearing capacity of foundation soil for the design of bridge foundation at Berbere Wonze River in Amahara Region South Wollo, Kombolcha, Ethiopia. The foundation investigation work includes a dynamic cone penetration (DCP) test, a standard penetration test (SPT), visual identification, groundwater monitoring, soil sampling, and subsequent laboratory tests on representative samples to determine the physical and engineering properties of the subsurface formations and soil underlying the proposed bridge sites. These are to provide safe and cost-effective foundations based on a combination of field data and laboratory test results.</p> VIJAYKUMAR NAGAPPA Copyright (c) 2021 VIJAYKUMAR NAGAPPA https://spast.org/techrep/article/view/1200 Fri, 24 Sep 2021 00:00:00 +0000 The effect of BP during the ECAP process demonstrated in FEM models and experiments for AZ31 https://spast.org/techrep/article/view/2276 <p>In this study, the equal channel angular pressing (ECAP) process was performed on the engineering magienium alloy (AZ31) with different Back Press (BP). The effect of BP on the strain condition and flow paths may differ as the statically deformed portion of the sample passes through the strain zone. Quantitative evaluation of the flow model is performed from the flownet of DEFORM tools for magienium alloy (AZ31). The BP application of 25, 50 and 100 MPa results in the forward rotation of typical shear structural coponents in the transverse direction.&nbsp; The complex (20 x 20 x 200) mm ECAP engine is used with movable outer walls and specially designed sliding bottoms for low friction (moving die). The flow model is made by a cubic flownet of the Deform tool on the workpiece. Structural features and initial micro- hardness measurements made on the X and Y planes of the workpiece also received a special attention. Since BP leads to increased density leading to the improved in micro-hardness can be attributed to the change in texture.</p> Quang Pham Copyright (c) 2021 Quang Pham https://spast.org/techrep/article/view/2276 Thu, 07 Oct 2021 00:00:00 +0000 Structural, Morphological, Magnetic and Optical Properties of Mn and Fe doped ZnO Nanoparticles https://spast.org/techrep/article/view/1275 <p>In this article, Pristine ZnO and its dopants with Mn and Fe i.e. (Zn)0.985(Mn).015O<br>(abbreviated as ZMnO)and(Zn)0.985(Fe).015O (abbreviated as ZFeO) were amalgamated by solid state<br>reaction method. The structural, morphological, optical and magnetic properties of the prepared<br>samples were studied. XRD established the crystalline, hexagonal wurtzite phase of pristine ZnO and<br>its doped variants. SEM images reveal that pure ZnO doped with Mn and Fe were in the nano scale<br>range having size of 20-100nm.UV study of the samples confirmed that energy band gap (Eg)<br>decreased from 2.92eVto 2.72eV with Mn doped ZnO While It is also decreased from 2.92eV to<br>2.73eV with Fe doped ZnO. The decrease in energy band gap may be due to the domination of dopant<br>ions. The diamagnetic ZnO exhibit paramagnetic behavior after doping with Mn and super<br>paramagnetic nature after doping with Fe.</p> sanjay kumar Copyright (c) 2021 sanjay kumar https://spast.org/techrep/article/view/1275 Fri, 15 Oct 2021 00:00:00 +0000 Microhardness study of binary blend of Polysulfone and Polyvinyledene Fluoride https://spast.org/techrep/article/view/637 <p>SPAST Abstracts Author Name(s), IGCSTS-1, 2021<br>Shabnam Qureshi1<br>, Swarnim Patel2<br>, Purvee Bhardwaj1<br>, Neetu Paliwal1 <br>1 Rabindranath Tagore University, Raisen, Bhopal (M.P.) <br>2 Govt. Polytechnic College, Katni (M.P.) <br>Email ID: swarnimpatel17@gmail.com <br>Abstract: The variety and combination of materials built from macromolecules of varying <br>complexities is limitless and still continue to grow as scientific endeavour and technological <br>application broaden and frequently merge. Blending may improve resin or product performance by: <br>Producing materials having a full set of the desired properties at lowest cost [1]. <br>Polymers exhibit a diverse range of physical properties, but it is the mechanical properties <br>which are usually of prime interest. Mechanical property depends on the state of the polymer and <br>involves the deformation of the material under the influence of applied force. The mechanical <br>properties of the polymers are one of the features that distinguish them from small molecules. During <br>the development of polymer science and engineering the search for structure property relationship has <br>occupied a central role for the control and prediction of the mechanical behavior of polymer and <br>blends [2]. <br>In the present investigation micro hardness study has been carried out by using Vickers <br>microhardness technique to study the effect of load on pure and blend samples. The emphasis has <br>been given on the study to investigate the saturation value of hardness number at which specimen is <br>expected to fully strain hardened. <br>Polysulfone (PSF) has a glass transition temperature of about 175°C. Polysulfone is <br>completely amorphous and transparent in their natural state [3]. Polyvinyledene fluoride (PVDF) is a <br>semi-crystalline polymer with Tg = -56 to -35°C, 50 % crystallinity, and melting temperature 160-<br>180°C. PVDF is also known for its piezo -and pyro- electric activities. It exhibits at least five phases <br>known as α, β, γ, δ and ε, α- form is non polar while β- form is polar and is responsible for all its <br>useful electro-active properties [4]. <br>The commercial PSF (Pallets) and PVDF (Powder) used for the present study were obtained <br>from Sigma-Aldrich Chemicals Private Limited (India). The samples in the present investigation were <br>prepared by the solution cast technique [3]. The solution of particular concentration was prepared by <br>dissolving the two polymers PSF and PVDF in different weight ratios in their common solvent N, N, <br>Dimethyl formamide (DMF) at 80°C. This solution was then poured on clean optically plain glass <br>plates kept on a mercury pool in a dust free oven at a constant temperature, T = 80°C, for 5 hr to yield <br>blend films which was then peeled off from the glass plates. For measuring the Vickers microhardness <br>number (Hv), the blend samples were indented by the mhp 160 microhardness tester with a Vickers <br>diamond pyramidal indenter having a square based pyramid with 136° angle, between them opposite <br>faces, attached to a Carl-Zeiss NU2 Universal research microscope. The load was varied from 10 to <br>80 g. The diagonals of the indentations were measured using a micrometer eyepiece. The value of Hv <br>was calculated from the relation:</p> <p>SPAST Abstracts Author Name(s), IGCSTS-1, 2021<br>?௩ = 1.854 ∗<br>?<br>?<br>ଶ<br>൬<br>??<br>??ଶ<br>൰<br>where L is load (kg) and d is the length (mm) of diagonals indentation (mm) at room temperature. For <br>each test, the duration of the indentation was kept at 30 s. For the same load, at least five indentations <br>were made at different points of the sample and the average hardness number was computed [5]. As <br>the load increases, the value of Hv becomes load-independent due to hardening up to the extent of <br>saturation. Also, the value of Hv tends to increase with increasing PVDF content. The increasing <br>content of PVDF in a blend causes an increase in stiffness in the blend samples.</p> Shabnam Copyright (c) 2021 Shabnam https://spast.org/techrep/article/view/637 Sun, 19 Sep 2021 00:00:00 +0000 Improving the bioactivity of hydroxyapatite through strontium substitution and forming a composite with graphitic carbon nitride https://spast.org/techrep/article/view/2788 <p>Bioceramics can be defined as biocompatible, biodegradable, bioactive and non-toxic ceramic materials that are used for the repair and reconstruction of diseased or damaged parts of tissues. Hydroxyapatite (HAP), [Ca<sub>10</sub>(PO<sub>4</sub>)<sub>6</sub>OH<sub>2</sub>] is one of the most common forms of calcium phosphate. It is a biocompatible and bioactive bioceramic which exhibits excellent osteogenic, osteoconductive, osteoinductive properties [1]. However, poor mechanical strength is a major limitation of HAP. Recently, graphitic carbon nitride (GCN) is emerging as a useful 2-dimensional material for biomedical applications. GCN is nontoxic, low density and has electron-rich properties GCN can be used for diagnostic imaging and therapeutic applications [2]. The characteristic properties of HAP and GCN suggest that HAP/GCN composites could help to overcome some of the major limitations of HAP such as low mechanical strength, inappropriate degradation rate (failure to complement <em>in vivo </em>bone regeneration) and most importantly, comparatively poor biological properties with respect to bone apatite. The brittle nature of HAP has been shown to improve by substituting a certain amount of strontium (Sr). Research has demonstrated that Sr can advance bone recovery and development by empowering osseous separation while lessening bone ingestion, by restraining osteoclasts arrangement [3]. Imparting better bioactivity is one of the prime requisite of materials used for biomedical application. In this perspective, the present study aims to synthesize HAP/GCN and Sr-HAP/GCN composites. The combination of strontium substitution and formation of a composite with GCN is hypothesized to impart a better bioactivity. The HAP/GCN and Sr-HAP/GCN composites are synthesized using 1.00 M solution of the calcium and strontium precursors and 0.67 M solution of the phosphate precursor solution. The pH of these solutions was maintained at 11.00. The reaction mixture was subjected to hydrothermal treatment at 150 °C for 2 h. The resultant powder was subsequently subjected to thermal treatment at 550 °C for 3 h. The schematic of the synthesis is depicted in fig. 1. The characteristic properties of these composites were evaluated using scanning electron microscopy, X-ray diffraction measurement, Fourier transform infrared spectroscopy and, X-ray photoelectron spectroscopy. The bioactivity of HAP/GCN and Sr-HAP/GCN composites was evaluated after immersing them in simulated body fluid (SBF) at 37 ± 1 °C for 21 days.&nbsp; Pure HAP was prepared using the calcium and phosphate precursors. Pure HAP powder is white in colour whereas the HAP/GCN and Sr-HAP/GCN composites are yellow in colour. The X-ray diffraction patterns of HAP, HAP/GCN and Sr-HAP/GCN composites are shown in fig. 2. The XRD pattern of pure HAP match well with the standard JCPDS file card 09-0432, thus confirming the formation of HAP. The XRD pattern of HAP/GCN composite shows the characteristic peak of GCN at 27.4° 2θ, which matches well with the JCPDS file card 87-1526 as well as the characteristic peaks of HAP, thus confirming the formation of HAP/GCN composite. Substitution of Sr leads to a change in diffraction patterns particularly at increased level of substitution. When compared to pure HAP, both HAP/GCN and Sr-HAP/GCN composites exhibit better bioactivity. The study concludes that the bioactivity of HAP can be improved by substituting strontium in place of calcium and by forming a composite with graphitic carbon nitride. The HAP/GCN and Sr-HAP/GCN can be explored for biomedical applications. &nbsp;&nbsp;</p> <p><img src="https://spast.org/public/site/images/saranya2021/fig.-1-saranya.png" alt=""></p> <p><img src="https://spast.org/public/site/images/saranya2021/fig.-2-saranya.png" alt=""></p> <p>&nbsp;</p> Saranya A., Vishwapriya U., Varun Prasad P., Sankara Narayanan T.S.N., Ravichandran K. Copyright (c) 2021 Saranya A., Vishwapriya U., Varun Prasad P., Sankara Narayanan T.S.N., Ravichandran K. https://spast.org/techrep/article/view/2788 Tue, 19 Oct 2021 00:00:00 +0000 INSILICO ANALYSIS OF THE BINDING AFFINITY OF 1-DNJ COMPOUND FROM MULBERRY PLANT AGAINST CARIES CAUSING ENZYME https://spast.org/techrep/article/view/2919 <p>The human mouth with its diverse niche and environmental changes, may lead to<br>formation of natural microbial biofilms [1] and Streptococcus mutans is a major contributor to<br>biofilm formation [2]. Traditionally, mulberry (Morus alba) is chewed in case of toothache to avoid<br>further cavitation. It is known for its anti-oxidation and anti-diabetic effect [3]. Biofilm formation is<br>mediated by glucans, and it is shown that mulberry extract can reduce polysaccharide-mediated<br>adherence of bacteria [4].</p> <p>To determine the binding affinity of 1-DNJ and Quercetin compounds of mulberry plants<br>against caries causing enzymes using molecular docking.</p> <p>The known caries causing enzymes which served as the target proteins namely, 3AIE<br>(Glucan sucrose),3BBA (Cystein Protease), 6TZ6 ( Calcineurin A), 6LOI(Undecarprenyl pyrophosphate<br>synthase), 4TQX (Soratse A) were downloaded from the library. The molecular docking study was<br>carried out using AutoDock software which uses Monte Carlo simulated annealing and LGA<br>(Lamarckian Genetic Algorithm) to create a set of probable conformations. The compounds 1-DNJ<br>and Quercetin were assessed against the target proteins and Ciprofloxacin was used as a standard<br>test compound</p> <p>Among the test compounds, 1-DNJ showed a better affinity against SoratseA enzyme<br>which is responsible for the adherence of S.mutans to the tooth surface. The results showed, the<br>compound 1-DNJ is a promising agent for further formulations for the prevention of dental caries.</p> Dhananjaya G Copyright (c) 2021 Dhananjaya G https://spast.org/techrep/article/view/2919 Fri, 22 Oct 2021 00:00:00 +0000 Bimetallic Co-Al layered oxide for augmenting the performance of capacitive deionization https://spast.org/techrep/article/view/2029 <p><span style="font-weight: 400;">Water is an important natural resource and is necessary for all plants and animals to survive. The available freshwater quantity is 2.5%, which also comprises glacier water, polluted water etc. By 2025, around 1.8 billion people are predicted to suffer from a freshwater shortage.</span></p> <p><span style="font-weight: 400;">Wastewater management and desalination of salted water are two major aspects to be in consideration to avoid the water shortage. Various technologies have been implanted to desalinate water like reverse osmosis, thermal desalination and electrodialysis etc.&nbsp; But cleaning water with high electrosorption capacity is still not achieved. To explore carbon-based nanomaterials for capacitive deionization. To synthesize materials with high surface area for higher efficiency. Desalination is a process that takes away mineral components from saline water. Desalination is used on many seagoing ships and submarines. Most of the modern interest in desalination is focused on cost-effective provision of fresh water for human use and irrigation. The capacitive deionization technique is an effective process for treating salinized ions of polluted water. The technology is based on employing an electrode material with a high specific surface area and porosity[1]. Advantages of CDI being that it</span> <span style="font-weight: 400;">enables salt removal at low pressures and room temperature and equires small cell voltage ( ~ 1V ). Capacitive deionization is a cost-effective approach to remove the salinity and getting clean water, A mechanism of Capacitive deionization (CDI) follows the deionization of water by applying an electrical potential difference over two symmetric/asymmetric electrodes, which are often made of porous carbon or battery type materials, with the feed flow directed through the electrodes themselves and parallel to the applied electric field direction. Negatively charged anions are removed from the water and are stored in the positively polarized electrode. Likewise, cations are stored in the cathode, which is the negatively polarized electrode [2]. The electrode for capacitive deionization requires high specific surface area and porosity.&nbsp; However, developing highly efficient materials with surface modification through nanostructures is important for enhancing capacitive deionization performances. Most specifically, transition metal oxides yield high specific performances and have emerged as potential materials as compared to conventionally used carbon in the field of capacitive deionization. They provide good ionic conductivity with uniform pore size and great nano-architecture. Here, we report a Co-Al mixed metal oxide as an electrode material for capacitive deionization. The work demonstrates a simple and effective strategy to prepare mixed metallic oxide over stainless steel (SS) mesh substrate for removing salt ions through capacitive deionization. One-step synthesis is utilized for the preparation of bimetallic oxide.&nbsp; Here a one-step method is used to form a metal oxide at 4000C temperature. The prepared material was characterized with cyclic voltammetry(CV), electrochemical impedance spectroscopy (EIS) and electrosorption isotherm to analyze the electrochemical and CDI performance of the material. Co-Al-LDO material has exhibited a high electrosorption capacity of 409.2mg/g at 1.2V of potential, which is much higher than the reported materials. Our study demonstrates the great potential of mixed metal oxides as novel materials for high-performance capacitive deionization of salted water.</span></p> Prajwal Gorle Copyright (c) 2021 Prajwal Gorle https://spast.org/techrep/article/view/2029 Sat, 09 Oct 2021 00:00:00 +0000 Development of Self Compacting Geo -Polymer Hybrid Fiber Reinforced Concrete with inclusion of Sustainable Materials. https://spast.org/techrep/article/view/2105 <p><strong>Abstract:</strong><br>The Self-Compacting Geo Polymer Hybrid Fiber Reinforced Concrete (SCGPHFC) is widely<br>developing concrete in the construction industry which is eco-friendly and sustainable concrete. In this<br>concrete, the materials involved are Fly ash (FA), Ground Granulated Blast Furnace Slag (GGBS) and<br>Metakaolin (MK) which acts as a building material. These materials act as binders and reduce the<br>emission of CO2 from the construction industry. Fly Ash is a by-product obtained from thermal power<br>plant which has more alumina-silicate content, where fly ash is completely replaced by cement which<br>is alternative binder to the concrete. The fly ash is replaced by 10% with GGBS and Metakaolin which<br>enhances the pozzolanic reaction and form geo-polymerization. The addition of SCGPC with the hybrid<br>fiber i.e., combination of two fibers, the total amount of fibers is 1.5% of the powder content which<br>represents the Self-Compacting Geo Polymer Hybrid Fiber Reinforced Concrete (SCGPHFC). A slump<br>cone, L-Box test and V-Funnel test are conducted to evaluate the fresh properties of the concrete.<br>Compressive Strength, Split Tensile Strength and Flexural Strength are conducted to evaluate the<br>hardened properties of the concrete. For the durability properties acid attack, rapid chloride ion<br>permeability test (RCPT) and Resistance to Concrete. The mix SCGPHFC5 i.e., 0.75% of steel &amp; PVA<br>fiber showed the greatest improvement in all the tests conducted among all the mixes. As the dosage of<br>fiber is constant the chloride ion penetration was reduced. The results for the concrete mix SCGPHFC<br>5 shows have attained high strength values compared to the other mixes of SCGPHFC.</p> Kaushik Chundury, Avinash, Rakesh Jangiti, Narendra Copyright (c) 2021 Kaushik Chundury, Avinash, Rakesh Jangiti, Narendra https://spast.org/techrep/article/view/2105 Fri, 01 Oct 2021 00:00:00 +0000 Porous Polymer Monoliths as Adsorptive Host Template for CeO2-CaO Nanocomposite Dispersion for Visible Light Heterogeneous Photocatalysis https://spast.org/techrep/article/view/544 <p>In this work, we report on the synthesis of CaO doped CeO<sub>2</sub> nanocomposites (NCs) prepared by a sonochemical-assisted temperature-controlled hydrothermal method. Considering the toxicity and recovery issues associated with nano-particles/composites, a novel approach has been attempted through the uniform dispersion of the CeO<sub>2</sub>-CaO NCs across a macro-/meso-porous polymer monolith template <strong>[1]</strong>. The structural and morphological properties of the synthesized photocatalyst materials have been monitored by p-XRD, FE-SEM-EDAX, HR-TEM-SAED, XPS, FT-IR, UV-Vis-DRS, PLS, and BET analysis. The visible-light photocatalytic performance is monitored using varying stoichiometric ratios of CeO<sub>2</sub>-CaO NCs with best results achieved using, 20 wt.% CaO doped CeO<sub>2</sub> NCs that are homogeneously dispersed on a 3D network of the porous polymer monolithic network. The CeO<sub>2</sub>-CaO NCs dispersed polymer monolith reveals superior photocatalytic activity in comparison to CaO doped CeO<sub>2</sub> NCs that are likely to agglomerate in aqueous solutions that eventually reduce their process efficiency. The CeO<sub>2</sub>/CaO NCs dispersed polymer monolith exhibit excellent porosity and surface area, for the ultra-fast dissipation of organic molecules, apart from being durable and reusable. For photocatalysis studies, we have chosen an antimicrobial drug namely moxifloxacin, for the visible-light-induced dissipation, to counter the problems associated with the emergence of resistant bacteria. We hereby state that the prepared monolithic NCs are easy to synthesize, cost-effective, and reusable, thus making them an ideal heterogeneous photocatalyst for pollutant dissipation.</p> <p><img src="https://spast.org/public/site/images/satyaprasadasu/mceclip0.png"></p> <p><strong>Scheme 1.</strong> Graphical representation of the proposed photocatalytic work.</p> SATYA PRASAD A, NAVEEN KUMAR S, AKHILA MAHESWARI M, PRABHAKARAN D Copyright (c) 2021 SATYA PRASAD A, NAVEEN KUMAR S, AKHILA MAHESWARI M, PRABHAKARAN D https://spast.org/techrep/article/view/544 Thu, 16 Sep 2021 00:00:00 +0000 Band-gap tuning of MoX2ZnO(X:S,Se) heterostructure by applying electric field https://spast.org/techrep/article/view/1638 <p>A new technique to tune the electronic properties,including bandgap and band alignment type of two dimensional heterostructure, is by applying electric fields [1,2].Tuning of the electronic properties of two dimensional Vander-Waals heterostructure of MX2(M:Mo,X:S,Se) and graphene like ZnO has been investigated as a function of external electric field using first principle calculations. For the first time. The effect of electric field is measured as change in the electronic energy bandgap proper- ties. The MoS2-ZnO heterostructure is a type-II band alignment with indirect bandgap of 1.61eV and a large built-in electric field (or a large potential drop of 7.42eV ) with a valence band offset of 1.22eV across the interface as shown in figure1. However MoSe2-ZnO is a type-I heterostructure with direct bandgap of 1.80eV and a built-in electric field 3.64eV with a band-offset of 0.31eV. The charge density is localised on MoS2 in VBM and ZnO in CBM but in MoSe2 for both VBM and CBM. A perpendicular electric field is applied to tune the bandgap value and the band alignment type (type-II®type-I) of the heterostructure. There is a cross-over in the bandgap type in MoS2-ZnO(MoSe2-ZnO )indirect®direct (direct®indirect) after a critical value Ef=0.75V/A (Ef=0.75V/A) of electric field. The tuning of charge transfer is explained on the application of electric field. Our work opens a way to engineer electronic and optoelectronic devices with the application of electric field which could be useful in photodetectors.</p> Neha kapila Sharma, Dr. Hitesh Sharma Copyright (c) 2021 Neha kapila Sharma, Dr. Hitesh Sharma https://spast.org/techrep/article/view/1638 Fri, 08 Oct 2021 00:00:00 +0000 Advances in incorporation of nanomaterials onto fabrics https://spast.org/techrep/article/view/1252 <p>Textile is a necessary commodity and is of paramount importance in a variety of areas. Textiles are frequently used for protection against heat, cold, rain, etc. among various other purposes. The properties of textiles can be further enhanced and the horizon of their applications can be broadened by the incorporation of nanoparticles using nanotechnology.&nbsp; Nanotechnology is currently a top priority in research across the world due to its enormous potential [1]. Nanoproducts ranging from nanofibers, nanocomposite fibers, and intelligent polymeric nanocoatings are frequently incorporated in conventional textiles to provide improved performance and new functionality [2]. Nanocoatings offer numerous specific properties like antimicrobial, regulated hydrophilicity/hydrophobicity, antistatic, wrinkle resistance, shrink-proof, and protection against UV radiations. These properties lead to a variety of textile applications including protective garments, medicinal textiles, and sportswear [3]. In the COVID-19 pandemic situation, nanotechnology has paved the way for need-based customization such as antiviral masks, PPE kits, etc.</p> <p>There's no doubt that nanotechnology will have a major impact on the textile industry soon. Innovations in nanotechnology have led researchers to incorporate nanosensors in clothing that can quickly adapt to climatic changes and customized apparel which monitor the vital signs of the individual. The need for nanocoated fabrics in the medical industry is immense. The use of Intelligent fabrics for table cloths, carpets, towels, seat fabrics, interiors, etc. for reducing the risk of cross-infection can be an area of research in the future [4].</p> <p>This paper provides an overview of the nanomaterials suitable for the textile industry, enhancement in the properties of fabrics due to incorporation of nanomaterials, advantages, disadvantages, and a few applications.</p> Ujwal Shreenag Meda, Samhita M Kiran, Shravan S Ranga Copyright (c) 2021 Ujwal Shreenag Meda, Samhita M Kiran, Shravan S Ranga https://spast.org/techrep/article/view/1252 Thu, 30 Sep 2021 00:00:00 +0000 Development of Mathematical Models for Estimation of 28 days Compressive Strength of Concrete with Fly Ash as one of the Ingredient https://spast.org/techrep/article/view/1328 <p>Last decade and half of the Twentieth century has witnessed phenomenal development in cements, with<br>the availability of high early strength cements and Portland Pozzolana cement. With the increase in<br>usage of fly ash in cement and concrete, strength characteristics of concrete have significantly been<br>enhanced. The known Abram’s Law based on water – cement ratio linking 28 days compressive strength<br>may need modification resulting in alternative to this law. The Authors have developed prediction<br>models for 28 days compressive strength based on water to cementitious material ratio using compiled<br>data from various references along with own data and developed alternative mathematical models. The<br>fineness of fly ash is known to have significant effect on the compressive strength development in<br>concrete has also been incorporated in the development of one prediction model. Presentation of these<br>models and their validation can certainly attribute towards development of modified Abram’s Law.<br>They can be judiciously used in estimation of compressive strength of concrete with fly ash as one of<br>the ingredients.</p> Vilas Meshram Copyright (c) 2021 Vilas Meshram https://spast.org/techrep/article/view/1328 Fri, 15 Oct 2021 00:00:00 +0000 The Effect of Coir Fibre Inclusion on Engineering Properties of Cement Stabilized Expansive Soil https://spast.org/techrep/article/view/2863 <p>The expansive soil has substantial volume changes due to the presence of the highly reactive clay mineral montmorillonite (it swells when it comes in contact with water and shrinks when water evaporates). Because of their limited bearing capacity and fast volume changes, expansive soils are one of the most difficult to work with. Due to this periodic change in volume, the structure is subjected to significant upheaval stresses, which can be harmful for low-rise structures.</p> <p>Adopting soil stabilization as a solution to deal with expansive soil is a very viable option. Soil stabilization refers to the process of enhancing the engineering and strength characteristics of expansive. It's a tried-and-true technique for dealing with low-capacity soils.</p> <p>First, expansive soil was stabilized with cement [1], [2], then waste coir fibre was added to the specimen of expansive soil and cement to offer strength to the soil[3]– [5]. As per Indian standard codes, various experiments were carried out to examine the engineering properties of soil and mix specimens, such as consistency limits, standard proctor test, CBR test, and UCS test[6]– [11].</p> <p>Initially cement was added in the soil in following proportions 0%,1%,2%,3%,4%, and 5%. The optimum results were obtained at 5% cement. Further coir fibre was introduced with the mixture of expansive soil and 5% cement, to provide the reinforcement. The coir fibre was added in the following proportions 0.5%, 1%, 1.5%, 2%, 2.5% and 3%. The optimum results were recorded at the dose of 2% coir fibre.</p> Ajay Pratap Singh Rathor, Harshil Bhatt Copyright (c) 2021 Ajay Pratap Singh Rathor, Harshil Bhatt https://spast.org/techrep/article/view/2863 Tue, 19 Oct 2021 00:00:00 +0000 Effect of preparation techniques and nanoparticles content on the morphological and mechanical properties of polylactic acid nanocomposites https://spast.org/techrep/article/view/2010 <p>The formation of the micro-voids is the most common manufacturing defect observed in various casting processes due to the presence of air in the polymer matrix, which deteriorates prepared nanocomposite’s mechanical properties [1-2]. The authors suggested a new preparation technique to minimize the formation of micro-voids in PLA nanocomposites. The nanocomposites preparation by new technique involved melt mixing assisted with ultrasonic vibration and casting under the vacuum chamber. The nanocomposite samples were also prepared by the conventional compression moulding and solvent casting techniques, to analyse the effect of processing techniques on the properties of PLA. Calcium phosphate (CaP) and Magnesium phosphate (MgP) nanoparticles were incorporated with different wt% to study the effect of nanoparticles on the properties of the PLA. The reason behind selecting PLA for the study in the present work is its predominant use in various biomedical and packaging industries for new items [3-4]. The scanning electron microscope (SEM) was used to study the morphological property of the PLA nanocomposites. The result shows that several microvoids were found on the surface of the nanocomposites only in the melt mixed and compression-moulded sample and were absent in ultrasonic assisted melt mixing and vacuum casting, and solvent casting methods. The nanoparticles start agglomeration even at lower nanofiller concentration in the case of compression-moulded samples. The tensile strength of the PLA nanocomposites increases up to 15 wt% CaP and 2 wt% MgP nanoparticles content. In compression-moulded samples, the tensile strength is not likely to be enhanced at lower filler content, due to void formation. Based on the results, ultrasonic assisted melt mixing and vacuum casting technique is found as the best technique.</p> Govind Sahu Copyright (c) 2021 Govind Sahu https://spast.org/techrep/article/view/2010 Sat, 09 Oct 2021 00:00:00 +0000 An Organic Solvent-Assisted Intercalation and Collection (OAIC) for Ti3C2Tx MXene with Controllable Sizes and Improved Yield https://spast.org/techrep/article/view/601 <p>Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> (MXene), a family of cutting-edge two-dimensional (2D) nanomaterials [1, 2], has a wide range of potential applications, including electromagnetic interference shielding [3], electrochemical energy storage [4, 5], catalysis [6], sensors [7], biomedicine [8], etc. As the building block of these important applications, more attention has currently been put on synthetic methods that can deliver the largescale demand of materials for real industrial applications. A good synthetic method of nanomaterials requires good controllability, high yield, low cost, green processes, and safety, which are the main factors in deciding that a synthetic method can leave laboratory demonstrations and go to mass production. Similarly, the continuous development of novel synthetic methods is present throughout the whole road-map of MXene materials [9]. Initially, Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> flakes were prepared by two steps including etching the Ti<sub>3</sub>AlC<sub>2</sub> (MAX phase) by concentrated hydrofluoric acid (HF) and then intercalating multilayered sheets with organic molecules, e.g., hydrazine, urea, and dimethyl sulfoxide (DMSO) (Route I in Fig. 1) [10]. However, the utilization of hazardous and toxic HF not only makes the operations risky, but the low yield ( 20%) [11] further suggests it could not possibly use in mass production. Later, a more moderate etching system was reported using the fluoride salt, LiF, mixed with HCl. In this system, HF is formed in situ with lithium ions intercalated during the etching process, resulting in Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> clay. After sonication in water, single Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> flakes with submicron lateral-size could be isolated (Route II in Fig. 1) [12]. The pros and cons are the avoidance of having to use HF, and the small size of Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> flakes with low yield, respectively. Recently, some further modifications have been developed to improve the yield and/or increase the size of Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> flakes [13-17].&nbsp;However, a method with a perfect trade-off that meets all the aforementioned requirements, inc., good controllability, high yield, low cost, green process, and safety, has to been achieved and remains challenging.</p> <p>In this work, a modified approach, organic solventassisted intercalation and collection (OAIC) is reported. The OAIC approach (Route III) is a modified method which combines a part of Route I and Route II, of which features include but not limited in the following ways.&nbsp;First, the LiF/HCl etching process is the same as Route II, which meets the moderate etching process.&nbsp;Second, intercalation is reinforced by DMSO, which is similar as most intercalating chemicals in Route I. Third, the well-known similia similibus solventur principle is adopted to remove the residual DMSO by DCM because the magnitude of solvent solvent interactions is much larger than solvent-nanoflakes interactions [18].&nbsp;In addition, the low boiling point of DCM (39.75 C at 760 mmHg) is what help DCM to volatilize by vacuum drying.&nbsp;Most significantly, inspired from the fabrication of graphene and Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> macro-fibers [19, 20], DCM washing efficiently restrain large weight loss in Route I which is caused by the step of water adding for removing DMSO because of the strong interactions between water and Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> flakes.&nbsp;After adding DI water, Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> flakes can be brought down from the supernatant by centrifugation (3500 rpm).&nbsp;The sediment can have DMSO added to further intercalate the residues, in which more Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> flakes can be extracted after DCM washing and centrifugation in water to enhance the yield.&nbsp;This step can be cycled at least 6 times;&nbsp;each cycle accumulates more Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> flakes with increased size in gradients, which is the fourth feature of OAIC approach and the first reported feature among all other approaches. The OAIC approach is reported to prepare Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> flakes in gram-level with enhanced yield (46.3%) and improved quality (area reaches ca. 4.60 μm<sup>2</sup>) through a facile approach featuring sonication-free and high-speed centrifugation-free (&lt;&nbsp;4000 rpm) methods. More importantly, the Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> flakes of different sizes can be obtained in different production cycles instead of gradient centrifugation.&nbsp;The Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> flakes with median size show the outstanding capacitive and rate performance.&nbsp;To our best knowledge, the OAIC approach that simultaneously meets aforementioned features of a good synthetic method is a novel procedure, which could shed new light on the mass production of other MXene materials in the future.</p> Danyao Qu Copyright (c) 2021 Danyao Qu https://spast.org/techrep/article/view/601 Thu, 16 Sep 2021 00:00:00 +0000 A Review on chemical bath deposition mediated synthesis of Binary/ Ternary Photoconductive Metal Sulfide Thin Films https://spast.org/techrep/article/view/1657 <p>Photoconductors are normally composed of semiconductors which show an enhancement in the electrical conductivity due to the absorption of photons.&nbsp; The first photoconductivity effect was observed in 1873 as scientists found a decrease in the resistivity of selenium upon radiation shining on it. When the photons of energy greater than that of the band gap of the material are incident upon a photoconductive material, the electrons and holes are created in the conduction and valence bands respectively, which in turn increase the conductivity of the sample. Photoconductivity arises when photons of energy greater than that of the band gap of the semiconductors materials are incident on the material, as a result of which, electrons and holes are created resulting in the enhancement of electrical conductivity. This phenomenon is called intrinsic photoconductivity. It is also possible to observe photoconductivity when the energy of the incident photon is less than that of the band gap. However, when the energy of the incident photon is less than the band gap of the material, but the energy of the photon matches the ionization energy of the impurity atoms, and upon shinning of photon they are ionized, creating extra carriers and consequently an increase in conductivity is observed. This phenomenon is called extrinsic photoconductivity. The II-VI and III-V groups’ compound semiconductors are of significant importance due to their technological applications. Zinc Sulphide (ZnS) is the II-VI group semiconductor with a direct band gap of 3.50-3.70 eV. On the other hand, cadmium sulfide (CdS) is also the II-VI group semiconductor with a band gap of 2.42 eV. It is a low resistivity semiconductor and can be utilized as a high transparent conducting sulphide in the visible range. Among the binary compounds PbS, ZnS and CdS are the most typical inorganic semiconductor materials owing to their band structure. Various technological applications require new and alternative materials with advanced properties. The properties of Zn<sub>1-x</sub>Cd<sub>x</sub>S thin films lie in between the properties of ZnS and CdS. Doping of Cd with ZnS can be tuned the band gap i.e., Zn<sub>1-x</sub>Cd<sub>x</sub>S changes the band structure and the Zn<sub>1-x</sub>Cd<sub>x</sub>S thin films have been widely used as a wide band gap window material in heterojunction photovoltaic solar cells and in photoconductive device.</p> <p>Moreover, PbS is photosensitive in the 800-3000 nm range (mid-infrared) at room temperature and is largely used in many applications, from the military domain to domestic life. CdS is photosensitive in the 400-600 nm range (visible) and is also used in manufacturing devices for various applications, including solar cells. Some ternary compounds based on CdS and PbS has been formed such as PbS with some percentage of Cd(Cd<sub>x</sub>Pb<sub>1-X</sub>S) and it has been observed by optical measurement that that the band gap value of this ternary compounds varies with x. In this review paper, we will emphasis the fabrication of thin film of binary and ternary metal-sulphide compounds by chemical bath deposition method.</p> <p>Chemical bath deposition technique has many advantages such as the deposition technique is simple, inexpensive and convenient for large area deposition at low temperature as highlighted by many researchers. In this present review, we will also report the chemical bath deposition mediated production of binary, ternary, and quaternary thin films. The influence of deposition parameters on the physical properties of films will also be reported in the present work.</p> <p>&nbsp;</p> Chandra Shekhar Verma Copyright (c) 2021 Chandra Shekhar Verma https://spast.org/techrep/article/view/1657 Fri, 08 Oct 2021 00:00:00 +0000 PHOTOENHANCED DEGRADATION OF CATIONIC DYE (METHYLENE BLUE) USING BIOGENIC TITANIA FROM MALUS DOMESTICA EXRACT https://spast.org/techrep/article/view/2344 <p>This work presents the Titania (TiO<sub>2</sub>) nanoparticles synthesized through green route using Malus Domestica for cationic dye removal. During Titania green synthesis, Malus Domestica extracts was utilized as stabilizing and bio-reducing agent due to its phytochemicals such as quercetin and chlorogenic acid. The Scanning electron microscopy micrographs show dense spherical shaped Titania nanoparticles arranged haphazardly. The anatase phase of Titania with a crystalline size of 13 nm was confirmed through the X-ray Diffraction pattern. The Titania formation bond of Ti-O-Ti confirms by the Fourier transform infrared spectroscopy. The UV–Visible spectroscopy also represents an optical active region in the visible spectrum at 390 nm of Titania. All the results obtained have revealed the complete formation of Titania through green synthesis using Malus Domestica. The photodegradation of MB (methylene blue) was evaluated using green Titania. The result shows maximum degradation of 98% acquired in 120 minutes of irradiation. Via the photodegradation study of biosynthesized Titania showed an excellent degradation efficiency compared to commercially synthesized Titania nanoparticles. Hence degradation efficiency indicates that the prepared green Titania nanoparticles are potential material for photocatalytic degradation application.</p> Aqsa Shaikh Copyright (c) 2021 Aqsa Shaikh https://spast.org/techrep/article/view/2344 Thu, 07 Oct 2021 00:00:00 +0000 Synthesis and Characterization of Silver Sulfide Nanoparticles for Photocatalytic Dye Degradation Applications https://spast.org/techrep/article/view/1836 <p>The untreated dye discharged wastewater is an alarming threat to the well-being of life on earth. Therefore, the researchers are opting for various methodologies to find and resolve the harmful effects of the discharge for the sustainability of the environment [1]. Moreover, dye degradation became challenging and inevitable due to increased wastewater, resulting in water scarcity. The nanotechnology research explores different semiconductor materials for the dye degradation application to overcome the same. Silver sulphide (Ag<sub>2</sub>S) is a direct bandgap semiconductor material [2]. It is known to depict outstanding photocatalytic performance due to its high capability of absorbing a broad solar spectrum in the field of environmental pollution protection through usage in wastewater treatment and energy conversion [2-4]. Ag<sub>2</sub>S nanoparticles have been explored in recent years due to their promising applications in microelectronics due to their specific optic, electronics and catalytic properties. Though there are different methods, some have disadvantages like high cost, generation of secondary pollutants, and low efficiency [5]. In this work, Ag<sub>2</sub>S nanoparticles are synthesised through a facile chemical route known as the co-precipitation method. Extensive attention was given to preparation and determining structural, optical and morphological properties of pure nanocrystalline Ag<sub>2</sub>S, emphasising synthesis conditions. The size and shape of the particle are influenced by different annealing temperatures. The samples were characterised by X-ray diffraction (XRD), Fourier transforms infrared spectra (FTIR), Scanning electron microscope (SEM), Energy Dispersive X-ray Analysis (EDAX), Ultraviolet-visible absorption measurements (UV-vis), and Photoluminescence (PL) along with Photo-dye degradation analysis. XRD analysis revealed that the synthesised Ag<sub>2</sub>S nanoparticles had no trace of impurities, signifying that the phase of annealed Ag<sub>2</sub>S does not undergo any phase change and shown high crystalline nature is depicted in fig. 1. The average crystallite size obtained was found to be 11.59 nm. The synthesised Ag<sub>2</sub>S nanoparticles have a monoclinic (space group P21/c), crystal structure. The lattice parameters, crystallite size, dislocation density, microstrain, unit cell volume is determined and tabulated in Table.1. &nbsp;FT-IR spectra confirmed the presence of the Ag-S band in the synthesised samples and confirmed the essential bonds. SEM analysis showed the surface morphology of the synthesized nanoparticles and confirmed the formation of the porous nanostructures in the shape of rods. Furthermore, the SEM analysis revealed the size of the obtained nanoparticles is in the range of 10 - 20 nm.&nbsp; EDAX and elemental mapping evidenced the presence of elements with appropriate composition and uniform distribution. The bandgap value of the sample was calculated by the Tauc plot method and is obtained as 1.0 eV, and it diminished due to the enhancement in carrier concentration with the increase in temperature. The inter-planar distances determined for the silver sulphide nanoparticles correspond to Photoluminescence measurements revealed the efficient separation of photogenerated charges in the Ag<sub>2</sub>S sample. The visible and NIR light photocatalytic activities were assessed by the degradation potential of chemically synthesised silver sulphide nanoparticles.&nbsp; The photocatalytic activities of Ag<sub>2</sub>S have been performed by photocatalytic degradation of Rhodamine B (RhB) and Methylene Blue (MB) in the presence of UV radiation. The decomposition of RhB efficiency and decay time had been calculated at the time of irradiation. The properties obtained from structural, optical, morphological and dye degradation analysis was apt for the wastewater treatment application.</p> <p>Table 1. Variations in the Crystallite Size, dislocation density, microstrain, unit cell volume of prepared Ag<sub>2</sub>S nanoparticles.</p> <table width="640"> <tbody> <tr> <td width="119"> <p><strong>Sample Code</strong></p> </td> <td width="86"> <p><strong>Crystallite Size (nm)</strong></p> </td> <td width="161"> <p><strong>Dislocation Density (lines/m<sup>2</sup>) x 10<sup>15</sup></strong></p> </td> <td width="132"> <p><strong>Micro strain (lines<sup>-2</sup>/m<sup>4</sup>) x 10<sup>-3</sup></strong></p> </td> <td width="142"> <p><strong>Unit Cell Volume (Å)<sup>3</sup></strong></p> </td> </tr> <tr> <td width="119"> <p>Ag<sub>2</sub>S</p> </td> <td width="86"> <p>10.36</p> </td> <td width="161"> <p>9.31</p> </td> <td width="132"> <p>6.20</p> </td> <td width="142"> <p>121.34</p> </td> </tr> <tr> <td width="119"> <p>Ag<sub>2</sub>S – 200℃</p> </td> <td width="86"> <p>13</p> </td> <td width="161"> <p>5.63</p> </td> <td width="132"> <p>6.20</p> </td> <td width="142"> <p>120.75</p> </td> </tr> <tr> <td width="119"> <p>Ag<sub>2</sub>S – 300℃</p> </td> <td width="86"> <p>12</p> </td> <td width="161"> <p>6.74</p> </td> <td width="132"> <p>6.20</p> </td> <td width="142"> <p>120.75</p> </td> </tr> <tr> <td width="119"> <p>Ag<sub>2</sub>S – 400℃</p> </td> <td width="86"> <p>11</p> </td> <td width="161"> <p>8.06</p> </td> <td width="132"> <p>6.14</p> </td> <td width="142"> <p>120.83</p> </td> </tr> </tbody> </table> Vijayan Karthikeyan, Vijayachamundeeswari S.P Copyright (c) 2021 Vijayan Karthikeyan, Vijayachamundeeswari S.P https://spast.org/techrep/article/view/1836 Sat, 09 Oct 2021 00:00:00 +0000 Vibrational spectroscopic and Optical absorption studies of Co2+ doped Lithium ion conducting Borophosphate Glasses https://spast.org/techrep/article/view/845 <p>A large number of Li+ ion conducting solid electrolytes, because of their property of being light in weight and having better electrochemical potential, are being developed for high energy density batteries [1, 2]. The composition, phase and microstructure of these solid electrolytes can be engineered in order to improve the various factors contributing to the conduction properties. For glassy electrolytes, its high ionic conductivity has been attributed to easier ionic motion in the disordered network of the glass, along with many advantages such as; absence of grain boundaries, isotropic properties, wide range of compositional and structural possibilities etc [3]. Although, Li+ ion conducting phosphate glasses exhibits low melting temperature, strong glass forming nature and high ionic conductivity, these glasses tends to be hygroscopic and has comparatively less chemical durability. However in the presence of the additional glass former (oxides) such as PbO, Al2O3, TiO2, GeO2 and B2O3, these phosphate glasses shows considerable improvements in physical and chemical properties. The enhancement in properties is attributed to “mixed former effect” [4–6]. In the current study, a second glass former B2O3 to mol% 50Li2O:50P2O5 system is being added for electrical and structural investigations in borophosphate glass.<br>Hence, mol% 50Li2O: (50−x)P2O5:xB2O3 (0&lt;x&lt;25) system was chosen, in which the total charge carrier concentration was kept constant while varying the concentrations of mixed former constituents. The current investigation is focused on how the mobility of Li+ ions is affected by the influence of mixed former effect, and also on how the structural modification of the phosphate glass network, in the presence of additional B2O3 glass former, influence the ion migration. The motivation behind the current investigation is to accentuate the under-used experimental technique of optical absorption spectroscopy, complimented with Raman studies. The Optical absorption and Raman spectroscopy studies are effective techniques in order to investigate the interaction of the modifier/dopant salt with glass former as well as local atomic arrangements and motion/ vibration of ions about their average sites in fast ion conducting glasses [7-9].<br>For the current chosen glass system, transition metal ion (Co2+) has been doped in Li2O:P2O5:B2O3 glasses for the optical absorption and raman spectroscopy studies in order to probe the local environment associated with Li+ ions and structural modification by introducing a second glass former.<br>Preliminary studies of optical spectra reported for sodium phosphate glasses shows that transition metal ions occupied the octahedral site symmetry in the host composition, mol% 50Na2O:50P2O5 [10]. Also, depending on the composition of the host lattice, the transition metal ions (Co2+ and Cu2+) occupy tetrahedral and octahedral site symmetries within sodium phosphate glasses [11].</p> <p>Figure 1(a) shows the variation in absorption spectra as second glass former is introduced in LiPO3 glass system. For all the three compositions, peaks are observed between 400 nm – 750 nm. And variations in the peak’s positions and intensities are clearly evident, with the change in glass composition. On deconvoluting, four peaks are observed, corresponding to the octahedral (400 nm – 600 nm) and tetrahedral (600 nm – 750 nm) co-ordination of Co2+ ions in the glass matrix. Mol% 50Li2O:50P2O5, exhibits both octahedral and tetrahedral coordination of Co2+ in its glass matrix. However, addition of B2O3 drastically modifies the<br>local structure as it can be seen that the intensity and area under the peaks corresponding to tetrahedral coordination increases for mol% 50Li2O:30P2O5:20B2O3. The deconvoluted peaks’ corresponding to tetrahedral co-ordination is more prominent in borate glass, mol% 50Li2O:50B2O3. Thus, the optical absorption spectra of Co2+ doped glasses indicate that the local environment of Li+ undergoes transition between octa- and tetrahedral coordination of O2- ion as the second glass former B2O3 replaces P2O5. In order to substantiate the findings of optical spectroscopy studies, Raman studies were carried out for the same glass compositions. Figure 1(b) shows the Raman spectra of the glass compositions which illustrate the effect of progressive substitution of phosphorous with boron in the glass system. it is evident from the Raman spectra that presence of B2O3 shortens the phosphate chains and new borophosphate (BPO4) structural units are formed, along with the formation of BO4 tetrahedral units in the glasses. The results obtained from optical absorption and Raman spectroscopic studies have together indicated shortening and disordering of (PO3)n n- chains and the bonding of borates to PO4 tetrahedral chain. There is an indication of the formation of borophosphate (BPO4) units, which enhances the thermal and chemical stability of the glass matrix.</p> MOHAN B N, Benson K Money, Vivek K. S. Copyright (c) 2021 MOHAN B N, Benson K Money, Vivek K. S. https://spast.org/techrep/article/view/845 Sat, 18 Sep 2021 00:00:00 +0000 Hydrogen based compounds as energetic catalysts for liquid rocket engines: Implications and Applications https://spast.org/techrep/article/view/351 <p>In the current scenario of space propulsion, liquid propellants have significantly proved useful in the upper stage rocket engines. Over the past couple decades, the world had inclined positively towards cryogenic fuel(s) viz., liquid oxygen and liquid hydrogen due to their high specific impulse. A higher specific impulse implies lower duration to achieve design cruise velocity for a given rocket initial and instantaneous mass. Liquid hydrogen and liquid oxygen as fuel and oxidiser can generate one of the highest&nbsp;<a href="https://en.wikipedia.org/wiki/Enthalpy">enthalpy</a>&nbsp;release in&nbsp;<a href="https://en.wikipedia.org/wiki/Combustion">combustion</a>, producing a&nbsp;<a href="https://en.wikipedia.org/wiki/Specific_impulse">specific impulse</a>&nbsp;of upto 450&nbsp;seconds at an&nbsp;<a href="https://en.wikipedia.org/wiki/Effective_exhaust_velocity">effective exhaust velocity</a>&nbsp;of 4.4 kilometres per second. Whereas, selected disadvantages are encountered in the form of storage and production. This indicates overdependence on cryogenic propellants and have necessitated the active research effort for better alternatives. As an interesting alternative, the combination of Dinitrogen Tetroxide (N<sub>2</sub>O<sub>4</sub>) and Monomethyl Hydrazine (MMH) have been used for many space applications owing to an extreme storage stability and hypergolic nature. Present study aims to express the effect of hydrogen-based compounds on the rocket performance. Four distinctive compounds from two groups of hydrogen-based compounds are tested with the varying oxidizer and fuel proportions to obtain a new, cost-effective and user-friendly composition that can be prepared at room temperature. The investigation attempt and explains the effect of hydrogen based energetic propellants using N<sub>2</sub>O<sub>4</sub> and MMH as the base composition for upper stage performance. The work is motivated by the need of efficient space operations with attractive propulsive alternatives to minimize over-dependence on cryogenics, which will ultimately result in cost effectiveness. Various energetic materials were tested with the base composition by using standard NASA-CEA complex chemical equilibrium model. The performance was evaluated in terms of variation in specific impulse and characteristic velocity both of which are significant parameters. To, validate the practical utility, the role of chamber pressure, supersonic area ratio and optimal Oxidizer to fuel ratio (O/F) was determined. The work led to two interesting findings, a composition of beryllium hydride with base composition for high performance of rockets and the negative impact of hydrogen on liquid propellants.</p> Triparna Ray Copyright (c) 2021 Triparna Ray https://spast.org/techrep/article/view/351 Tue, 14 Sep 2021 00:00:00 +0000 Graphene Reinforced Portland Pozzolana Cement Composite with Improved Strength for Reduced Carbon Emission https://spast.org/techrep/article/view/1407 <p>Worldwide increase in greenhouse gas emissions resulting in global<br />warming and is causing an adverse effect on the land and aquatic<br />species. One of the major components of greenhouse gases in carbon<br />dioxide (55%) which is released in the atmosphere by different sources.<br />Cement is the key ingredient of construction materials. Its production<br />contributes about 3.2% of CO2 emissions. The present work elaborates<br />the constituents, major sectors responsible for greenhouse emission,<br />various techniques to reduce CO2 emission, synthesis of graphene and<br />fly ash reinforced Portland Pozzolana cement (PPC) composite with<br />different days of curation. The proposed work also reports the study of<br />compressive strength of synthesized composites and its dependence on<br />the curation time. The results revealed that graphene and fly ash induce<br />cement was found to be more robust, durable, efficient, and helps<br />significantly in reducing CO2 emission.</p> Meena Laad Copyright (c) 2021 Meena Laad https://spast.org/techrep/article/view/1407 Thu, 07 Oct 2021 00:00:00 +0000 Periodic surface defects on ultrathin Cu nanodisks for nitrate electroreduction to produce ammonia efficiently https://spast.org/techrep/article/view/426 <p>Ammonia has wide applications in agriculture and chemistry industry, it is also seeing important use in the future as a carbon-free energy carrier to decarbonize the global economy.[1] While presently, most ammonia is manufactured by the Habor-Bosch process which uses ultrapure nitrogen and hydrogen gas as the feedstock. Both gases are produced with high cost, especially the hydrogen production that emits a large amount of greenhouse gas and inputs high energy. [2] With the effort made by researchers, ammonia can be synthesized via many clean and feasible routes, with the electrochemical nitrate reduction (ENR) more interesting that transforms the toxic nitrate ions to value-added ammonia rather than useless N<sub>2</sub>. Efficient ENR with high ammonia yield depends on catalysts. Recent studies have shown that some metal oxides like TiO<sub>2</sub>, and metals like Pd, Cu are active to the ENR to produce ammonia. [3-5] Among them, Cu shows great potential due to high intrinsic activity, selectivity, and low cost. However, the development of nanostructured Cu has been challenged, especially for those with well-defined crystalline faces. [6] Cu triangle sheets have been reported to catalyse CO<sub>2</sub> to hydrocarbons, while the dimension of the Cu triangles lie in the microscale. Uniform and stable Cu nanodisks with the size down to 100 nm is still not available.</p> <p>Here we develop a facile method for the synthesis of stable and uniform freestanding Cu(111) nanodisks with the size less than 80 nm. The thickness of the Cu(111) nanodisks is 7 nm. The as-synthesized Cu nanodisks electrocatalytically transform nitrates to ammonia with the Faradaic efficiency as high as 78.9%. The highest ammonia yield rate reaches 2161 μg mg<sup>-1</sup><sub>cat</sub> . The stability is ascribed to the ultrathin oxidized surface. The high activity originates from the reconstructed periodic Cu atoms after the removal of surface oxygen, demonstrated by theoretical calculations.</p> Congcong Sun, Keming Wu, Zhenhuan Zhao, Xiaoxia Ba Copyright (c) 2021 Congcong Sun, Keming Wu, Zhenhuan Zhao, Xiaoxia Ba https://spast.org/techrep/article/view/426 Thu, 16 Sep 2021 00:00:00 +0000 A comprehensive review on the tape casting of ceramic nanocomposite https://spast.org/techrep/article/view/1518 <p>The tape casting is a low-cost technique which is used for the processing of ceramics, ceramic composites to make thick films for various applications such as capacitors, resistors, multilayer varistors, inductors. The green tapes are prepared by casting aqueous or organic solvent-based slip (powdered raw material suspended in a liquid) containing the ceramic powders, solvents, binders, plasticizers, surfactants, dispersants etc. to form the thick films/ tapes [1, 2]. In this paper, slurry preparations with different solvents (aqueous and non-aqueous) to make thick films of ceramic materials are elucidated. Preparation of slurry is pretty complex, therefore understanding the slurry physical properties like Zeta potential, rheology, viscosity as well as solid loading of slurry is important to achieve good quality films/tapes [1, 3-7]. The tape is very sensitive to some parameters during drying like humidity, drying rate, thickness of the film, compositions so on and so forth. Aqueous system has a number of advantages like non-toxicity, incombustibility and low cost over organic solvent-based system. However, an aqueous suspension has some disadvantages of high evaporation latent heat and inferior drying characteristics, and problems associated with the quality of the tape also arises [1-4]. The quality of the film is dependent upon the ratio of the additives (like binder, plasticizer), amount of solvent and particle size and size distributions of the materials. Understanding of all these parameters are required which helped in better design of experiments in order to improve the properties of the devices [2, 8, 9, 10]. In this review, we also cover the recent development of processing of various materials by tape casting and critically comments on industrial practises for diverse applications.</p> abhishek giri, Kaliyan Hembram, Kaliyan Hembram, Prachi Tadge, Sudeshna Ray Copyright (c) 2021 abhishek giri, Kaliyan Hembram, Kaliyan Hembram, Prachi Tadge, Sudeshna Ray https://spast.org/techrep/article/view/1518 Thu, 07 Oct 2021 00:00:00 +0000 Numerical Studies on Stability of Sand Slopes https://spast.org/techrep/article/view/2726 <p>Stability analysis of slopes is generally performed to assess the safe design of man-made or natural slopes (e.g. embankments, road cuts, open-pit mining, excavations and landfills etc.) Successful design of the slope requires geological conditions and properties of soil at site, geometry of slope, water table effect and seismic action etc. Choice of analysis method depends on both site conditions and the probable mode of failure, with consideration being given to the varying strengths and limitations involved in each method. Wide variety of slope stability software using limit equilibrium concept is available including search of critical slip surface provides the lowest factor of safety of model slope [1, 2, 3, 4, 5, 6, 7]. Numerical techniques provide an approximate solution to field problems which otherwise cannot be solved by conventional methods due to complexity in geometry, anisotropic material, non-linear behaviour and in situ stresses. Many studies are available to understand stability of soil slopes with and without inclusion of reinforcement in slope and minimum studies are available to check stability of sand slopes. An attempt is made to check stability of sand slopes with and without reinforcement. Present study presents results of stability of unreinforced and reinforced model slopes using GEOSTUDIO 2020 and stability calculations were performed using SLOPE/W module and factor of safety of slope is computed by considering various methods for both unreinforced and reinforced soil slopes. Soil is modeled as a Mohr-Coulomb material in the analysis. As the factor of safety of slope increased from unstable to stable condition in terms of factor of safety, seismic slope deformation analysis was also carried out on unreinforced and reinforced slopes using QUAKE. The soil properties obtained from laboratory investigation was given as input parameters and analysis was carried out for different types of model slopes. From the deformation analysis, it is observed that slope deformations are observed to be decreased with inclusion of reinforcement in sand slopes. From the results, it is also observed that there is tremendous decrease in deformations with increase in number of reinforcement layers in the sand slopes. The results from numerical studies in terms of factor of safety and reduction of deformations will be presented and discussed in detail.</p> Srilatha N, ksheeraja A L Copyright (c) 2021 Srilatha N, ksheeraja A L https://spast.org/techrep/article/view/2726 Thu, 21 Oct 2021 00:00:00 +0000 Effective Depth of BC Soil and Its Variation When Modified With Coir Fibres https://spast.org/techrep/article/view/1675 <p>The main objective of the manuscript is to investigate the basic qualities of BC Soil (BCS) and <br>coir fibre, as well as to reduce construction costs by utilizing naturally occurring coir fibres and <br>industrial waste products. To determine the strength of BCS, different sizes of model footings <br>of 0.05m are reinforcing to Treated Coir Fibre (TCF) resting on loose stratum. A comparison <br>is made between TCF-reinforced BCS and unreinforced BCS under static load conditions. <br>Blending with TCF in various proportions for different densities and experimenting with new <br>chemicals or compounds that make coir fibre more water repellent can also be done. The full <br>results of this study are concluded as for distinct settlements of footings carried by RDCFs <br>based on the laboratory experiments results and observation gained owing to the addition of <br>TCF to BCS. B-footing depths of 0.2B, 0.4B, 0.6B, 0.8B, 1B, 1.2B, 1.4B, 1.6B, 1.8B, and 2B <br>are the reinforcing depths for reinforced soils. The earth is impacted to a depth of 2 to 2.5 <br>times the breadth of the footing, indicating that the size of the footing is growing.</p> Shashank S T, Divya Shree H M, vinod B R, Syed Nizamudeen S, Dasharath D Kotian Copyright (c) 2021 Shashank S T, Divya Shree H M, vinod B R, Syed Nizamudeen S, Dasharath D Kotian https://spast.org/techrep/article/view/1675 Thu, 30 Sep 2021 00:00:00 +0000 Transformerless Inverters and Loss Analysis with Si, SiC and GaN Switches https://spast.org/techrep/article/view/1721 <p>Grid-connected solar inverters are popular in recent years due to the development of renewable energy sources. The development of transformerless inverters is dominant due to their low cost, size, and high efficiency. The critical issue in transformerless inverters is leakage current generation, which is hazardous to humans and equipment. Also, the leakage current distorts the grid current [1]. This paper presents a new family of pseudo-DC link-based high gain transformerless inverters, which use the AC decoupling method [2] to mitigate the leakage current according to the German standard VDE0126-1-1 [3-4]. As these inverters can boost the voltage more than nine times, the inverters can inject power to the grid even with less input voltage. As these inverters belong to pseudo-DC link type, the DC link capacitor and its charging diode are not needed. Thus these inverters reduce the size and loss, also improve the boosting capability compared to conventional two-stage PV inverters. The high gain capability avoids frequent interruption of grid integration, which usually happens in traditional transformerless inverters under poor irradiation conditions. The proposed inverter topologies are simulated in MATLAB Simulink to validate their operation. The thermal behavior of semiconductor switches in the inverters, made of three different materials (Silicon, Silicon Carbide, and Gallium Nitride), are analysed using the PLECS software [5-6]. The thermal behaviour proves that the proposed inverters can work with nominal heat sink itself. The conduction, switching, and reverse recovery losses of the semiconductor switches made of three different materials are analysed. The scaled-down experimental laboratory prototype made of silicon switches is developed to validate the simulated results.</p> Sahaya Ponrekha A Copyright (c) 2021 Sahaya Ponrekha A https://spast.org/techrep/article/view/1721 Fri, 08 Oct 2021 00:00:00 +0000 Eco - friendly synthesis of Pt nanoparticles by plant extract https://spast.org/techrep/article/view/2415 <p>Eco-friendly synthesis is a strategy to reduce the formation of harmful chemical products by using environment conscious synthesis procedures. One of the green methods for avoiding pollution is plant-mediated synthesis. In plant-mediated synthesis of nanoparticles, plant parts like leaf, bark, fruit, gum, and tuber are utilized as the reducing and stabilizing agent for the conversion of metal precursor to nano sized particles. Terpenoids, flavonoids, alkaloids, tannins, and phenols are identified in almost all part of a plant, including flowers, leaves, fruits, and roots, and can act as both reducing and stabilising agents. Plants such as<em> Anacardium occidentale </em>[1], <em>Antigonon leptopus</em>[2], <em>Azadirichta indica</em> [3],<em> Cacumen platycaldi </em>[4], <em>Camellia sinensis </em>[5], <em>B. prioitis </em>[6], <em>Fumariae herba </em>[7], <em>Gloriosa superb </em>[8], <em>Doipyros kaki</em> [9], <em>Pinus resinosa </em>[10], <em>Phoenix dactylifera </em>[11], <em>Lantana camara </em>[12],<em> Terminalia chebula </em>[13], <em>Prunus xyedoensis </em>[14], <em>Punica granatum </em>[15] have been reported as reducing agent and stabilizing agent for the synthesis of Pt NPs. Size of the plant based synthesized Pt NPs were in the range of 0.83 to 190nm with spherical, irregular rods, circular, hexagonal, monodispersed and spherical shapes. Biosynthesized PtNPs from B. prioitis were found to have significant cytotoxic effects on the MCF7 breast cancer cell line [6]. Phoenix dactylifera PtNPs were found to have antibacterial activity against B. subtilis and E. coli. The production of circular-shaped PtNPs with an average size of 10–50 nm from <em>Pinus yedoensis</em> tree gum extract was found to have effective antifungal activity [14].</p> Alwin David S, Subramanian P, Karuppuraja M, Amala Jothi Grace G Copyright (c) 2021 Alwin David S, Subramanian P, Karuppuraja M, Amala Jothi Grace G https://spast.org/techrep/article/view/2415 Mon, 11 Oct 2021 00:00:00 +0000 Design and Development of a Low Cost, Less Weight, and Lead-free Composite Materials for Radiation Shielding https://spast.org/techrep/article/view/368 <p>The paper analyses the performance of various composite materials in the lead-free apron for radiation shielding in biomedical applications. The challenging task is to extend the duration of wearing an apron, reduce the weight, and increase the comfort level for physicians. The lead-free composite materials used an alternative to lead in an apron due to their excellent properties such as mass attenuation coefficients, effectiveness against gamma radiation, flexibility and light-weight, and absorption. The present study discusses different simulation software used to assess the properties of the shielding material against the radiation effects. At the end of the paper, the promising directions are presented for future research</p> <p>Exposure to radiation for a longer period leads to hazardous effects on the human body [1,2]. Therefore radiation shielding aprons are essential for the people who are exposed to radiation in medical applications. In photon shielding, a medium that has a relatively high mass density is considered to have the potential to attenuate or block the intensity of these photons by a number of different methods including photoemission and scattering. [3,4]. Radiation shielding aprons commonly use lead material due to its excellent properties, which have been around for a longer period [5]. In advance, the method called Monte-Carlo simulation (MCNP) has been widely followed in the studies that comprise of the designing and testing of new materials for radiation shielding as shown in Figure 1 [6].</p> Sivakumar Rajagopal, Suya Prem Anand Copyright (c) 2021 Sivakumar Rajagopal, Suya Prem Anand https://spast.org/techrep/article/view/368 Tue, 14 Sep 2021 00:00:00 +0000 Sputter Deposited CuO Thin Films for Photovoltaic Application https://spast.org/techrep/article/view/1125 <p>In this present research work, we have synthesised CuO thin films on different substrate using DC reactive magnetron sputtering technique. The electrical properties of the sputter deposited CuO thin films were determined using I-V measurement. The structural characterization of sputter deposited CuO thin films was done by using X-ray diffraction (XRD) and Raman spectroscopy. XRD results confirm the monoclinic phase of the CuO thin films and the particle size was estimated by scherrer formula for as deposited CuO thin films at different substrate. The Raman analysis confirms the formation of high purity CuO thin films. Surface morphology and elemental composition of CuO thin films were studied by Scanning Electron Microscopy (SEM) and Energy dispersive X-ray (EDAX) respectively. SEM study shows the smooth surface and high porosity CuO thin films and the EDAX study confirms the &nbsp;presence and percentage of Cu and O in the sputter deposited CuO thin films. The optical properties like refractive index, extension coefficient and band gap were investigated by using ellipsometry and photoluminescence (PL) in the spectral range of 200 nm to 900 nm. CuO attract great interest for their industrial purpose use such as solar cells, photovoltaic, gas sensor and lithium batteries. These results show that, the electrical, structural, optical and morphological properties of as deposited CuO thin films vary with nature of substrate and may be suited for photovoltaic application.</p> Prashant Yadav Beer Pal Singh Copyright (c) 2021 Prashant Yadav Beer Pal Singh https://spast.org/techrep/article/view/1125 Thu, 23 Sep 2021 00:00:00 +0000 Effects of fabrication dynamics on the current transport behaviour of Ag/p-SnTexSe1-x Schottky diodes https://spast.org/techrep/article/view/2248 <p>The current research is focused on the engineering of materials which usually are binary of ternary compound semiconductors. These materials are joined in multi-layered formations to fabricate devices useful in photovoltaic, optoelectronic, and sensor applications.&nbsp; The present work has been undertaken on the Ag/p-SnTe<sub>x</sub>Se<sub>1-x</sub> circular-shaped Schottky barrier diodes (SBDs) formed on FTO-coated glass and ITO-coated polymer substrates. The schematic diagram of these Schottky diodes is shown in Fig 1a; the images of corresponding SBDs appear in figures 1b-c. The conducting channel representation of the vertical SBDs showing current spreading is shown in Fig 1d. The SnTe<sub>x</sub>Se<sub>1-x</sub> alloy undertaken for investigation is a mixture of orthorhombic SnSe and hexagonal Te phases, which showed either Te-rich or SnSe-rich compositions depending on the substrate temperature. The forward current-voltage ( I-V) characteristics of the Ag/p-SnTe<sub>x</sub>Se<sub>1-x</sub> formed on both the substrates exhibit 'a double threshold' behaviour. This behaviour may be due to surface defects and the patches of low barrier heights at the metal-semiconductor (MS) interface. Moreover, the Ag/p-SnTe<sub>x</sub>Se<sub>1-x</sub>/FTO SBDs provide superior current transport behaviour than the SBDs fabricated over the ITO polymer. These SBDs provide more good contacts of the 2D layers of&nbsp; SnTe<sub>x</sub>Se<sub>1-x</sub> semiconductors with FTO glass [1]. The values of ideality factor (η) and series resistance (R<sub>s</sub>) of Ag/p-SnTe<sub>x</sub>Se<sub>1-x</sub>/FTO SBDs increase; zero-bias barrier height (ϕ<sub>bo</sub>)&nbsp; decreases with increase in the area of the metal-semiconductor (MS) interface. The increase in the patches of low BHs and surface roughness are responsible for these changes in diode parameters. The variations in the hysteresis loop formation of the current-voltage (I-V) characteristics and the change in frequency on the capacitance of Ag/p-SnTe<sub>x</sub>Se<sub>1-x</sub>/FTO SBDs were analysed. The formation of the hysteresis loop is attributed to the deep levels of high density and high activation energy values of the SnTe<sub>x</sub>Se<sub>1-x</sub> alloy films. The experimental results show that the value of capacitance (C) increases with a decrease in frequency. The higher values of C at low frequencies are attributed to the high dielectric values.&nbsp; Such a variation of capacitance values, especially at low frequencies, is attributed to higher surface states (N<sub>ss</sub>) and relaxation time (τ)[2].&nbsp; The value of N<sub>A</sub> decreases, ϕ<sub>b,c-v</sub> increases with the increase in frequency. This behaviour of N<sub>A</sub> and ϕ<sub>b,c-v </sub>is attributed to the density distribution of N<sub>SS</sub> and the interfacial layer. The films deposited at different substrate temperatures&nbsp;&nbsp; ( 353 K, 403 K and 453 K ) were used in the Schottky diode formations. As the substrate temperature on which these diodes are fabricated rises, the diode parameters viz. ideality factors and series resistance decrease and the barrier height increases. The changes in the behaviour of p-SnTe<sub>x</sub>Se<sub>1-x</sub> 2D-layers on change of substrate temperature are attributed to a reduction of the 'Te' constituent&nbsp;in the alloy, which changes the lattices strains and unit cell parameters of&nbsp; 'Te' and 'SnSe'. The deviations in the structural parameters bring changes in the photo converter and optoelectronic behaviour of these films and affect the SBD <em>parameters. </em></p> <p><em>&nbsp; </em></p> NARESH PADHA Copyright (c) 2021 NARESH PADHA https://spast.org/techrep/article/view/2248 Thu, 07 Oct 2021 00:00:00 +0000 Green synthesis of Cr2O3 nanoparticles using microbes https://spast.org/techrep/article/view/1248 <p>Amid metal oxides, chromic oxide nanoparticles are more perceptible due to hardness, antiferromagnetic property, stability, chemical resistance, anticancer propery, antibacterial activity, antileshmanial activity. Bacterial strains like <em>Erwinia amylovora </em>[1]<em>, Shewanell oneidensis MR-1 </em>[2]<em>, Aspargillus niger </em>[3]<em>, Bacillus subtilis </em>[4]<em> and Bacillus cereus </em>[5] were used for the synthesis of Cr<sub>2</sub>O<sub>3</sub> NPs from the chromium salt precursors. Bacterial strains were used as both reducing agent and capping agent. The obtained nanoparticles were characterized by UV–vis, XRD, SEM, TEM, EDS and TGA. UV–vis spectrophotometric analysis of the Cr<sub>2</sub>O<sub>3</sub> NPs confirmed the formation of NPs, which showed the surface plasmon resonance SPR in the range of 250–450 nm. X-ray diffraction revealed crystallite sizes of Cr<sub>2</sub>O<sub>3</sub> NPs which was calculated using Scherrer’s equation. It was reported that the size of the Cr<sub>2</sub>O<sub>3</sub> NPs is in the range of 4 -78 nm. The green synthesized Cr<sub>2</sub>O<sub>3</sub> NPs were in hexagonal, circular and spherical in shape. Antibacterial and cytotoxicity were studied for Cr<sub>2</sub>O<sub>3</sub> NPs which exhibited superior antibacterial activity and cytotoxicity.</p> Alwin David S, Ramkumar P Copyright (c) 2021 Alwin David S, Ramkumar P https://spast.org/techrep/article/view/1248 Thu, 30 Sep 2021 00:00:00 +0000 Structure and properties of coatings obtained electroslag surfacing of Si3N4 + FeSi2 + Si alloy, alloyed low alloy steel * https://spast.org/techrep/article/view/1673 <p>The paper presents the results of studies of the influence of alloying on the structure,<br>hardness and abrasive wear resistance of layers deposited on the surface of low-alloy<br>structural steel of the 13Mn6 type (?????? 0,12 % ?; 0,5 − 0,8 % ??; 1,3 −<br>1,7% ??; ?????? 0,04 % ?; ?????? 0,035 % ?) by electroslag surfacing. For modification, we<br>used mixtures of Si3 N4 + FeSi2 + Si powders obtained by the method of self-propagating hightemperature synthesis, as well as powder compositions based on TiC. From low-alloy steel<br>type St-37 (0,14 − 0,22 % ?; 0,15 − 0,3 % ??; 0,4 −<br>0,65 % ??; ?????? 0,05 % ?; ?????? 0,04 % ?), a meltable electrode was made, on which, in<br>the first case, the modifying composition Si3N4 + FeSi2 + Si was poured on top, and, in the<br>second case, the modifying composition Si3N4 + FeSi2 + Si was placed below (under the<br>electrode). The structure was determined by the methods of optical metallography and X-ray<br>microanalysis and the analysis of the composition of the deposited layers, the heat-affected<br>zone and the base metal was carried out. Based on this, assumptions were made about the<br>effect of the structure on the properties of coatings - hardness and wear resistance. The<br>positive effect of modification of coatings with alloying materials " Si3N4 + FeSi2 + Si on St-37",<br>"TiC on St-37" has been established. A large number of new crystallization centers in the form<br>of dispersed TiC particles are generated in the molten layer. Dispersed TiC particles with a<br>high melting point (3180 ° C) are the first to fall out of the melt and serve as both crystallization<br>centers and prevent grain growth, which ensures the formation of a dispersed structure. The<br>coatings contain particles of TiC carbide, as well as inclusions of other phases. In this case,<br>an increase in the hardness of the deposited layer containing inclusions of titanium carbide is<br>observed in the direction of the interface with the base. The wear resistance of the layer<br>increases with the formation of a TiC-based coating.</p> Alexander Nepomnyashiy, Yuri Saraev, Vyacheslav Semenchuk Copyright (c) 2021 Alexander Nepomnyashiy, Yuri Saraev, Vyacheslav Semenchuk https://spast.org/techrep/article/view/1673 Fri, 08 Oct 2021 00:00:00 +0000 Base-activated Sodium bentonite clay: Mutated characteristics and industrial slant https://spast.org/techrep/article/view/2450 <p>The industry approach for natural montmorillonite clay has been reported. Modified clays have enhanced physicochemical properties with good acceptance characteristics for different types of industries such as cement, pharmaceutical, paper, rubber, wood, and waste recycling processes. This innovative work deals with the promising behavior of mutated sodium bentonite concerning the elemental, thermal, structural, and morphological study. In this research, commercial sodium bentonite clay has been activated with 4M of sodium hydroxide. Characterization techniques of SEM/EDAX, FT-IR, XRD, TGA, and DTA/DSC have been reported to investigate mutated characteristics after the base activation. Both the samples have been reported with CO<sub>2</sub> compounds. The spectrum of silicon monoxide compounds of medium sharp Si-O-Si stretching frequencies 470.79 cm<sup>-1</sup> and 459.37 cm<sup>-1</sup> have been listed respectively for SB and BTSB. Strong broad Si-O Stretching of peak 539.26 cm<sup>-1</sup> has been assigned for alkyl halides in SB. Absorbed water and alkyl halide compounds have been removed after base treatment. The low presence of hydroxyl, benzene and alkynes derivatives has been traced in the BTSB sample. A sharp fall in weight has been found within the temperature ranges from 20º C to 400º C due to the hydration of water. Removal of octahedral Al ions has been initiated. Continuous loss of hydroxyl compounds is caused by the major weight loss within the glass transition range from 0º C to 110º C. The maximum value of FWHM for BTSB has been reported as 0.491 for 2.098 of d- value at the absorption peak of 43.08º. The maximum values of crystallite sizes have been listed by Scherer’s equation as 77.71 nm and 203.3 nm for SB and BTSB at the absorptions peaks of 86.02º and 6.56º respectively. It has been observed that broad peaks pinpoint the decreased crystallite size. Maximum d-values 14.198 and 13.463 have minimum crystallite size 04.45 nm and maximum crystallite size 203.3 nm for SB and BTSB respectively. At atmospheric conditions, samples refluxed and calcined at 105º C and 500º C respectively for three hours. Anhydride, carboxylic acid, and alkyl halides have been removed after base treatment. The XRD data reveals that the crystallite size (average) is more than three times the parental after mutation. The atomic and weight percentage of silicates have been improved respectively from 45.4 % to 53.02 % and 41.87 % to 62.85 %. Morphology shows an untreated sample has an unsymmetrical bed type layer that has been improved and a bunch of similar structure molecules has been found similar to the fibers. It has been found that silicates have been increased by 118.65 % by weight % after base treatment. A vital increment has been noticed for aluminates as 316.12 % of weight %. Impurities like Ti and wallastonite have been removed and the modified base activated sodium bentonite sample has enhanced characteristics for industrial applications. Fewer amounts of iron particles have been traced and a high percentage of albite is noted. A sharp and smooth fall has been recorded due to perennial loss of hydroxyl groups and hydration water at 100º C. The modified structure of the commercial sodium bentonite has a prominent behavior relevant to the different industrial aspects. The thermal analysis also satisfies that the different and useful microstructure is developed after base activation.</p> <table> <tbody> <tr> <td width="209">&nbsp;</td> </tr> <tr> <td>&nbsp;</td> <td>&nbsp;</td> </tr> </tbody> </table> <p><br><br></p> AWINASH KUMAR, Pradip Lingfa Pradip Lingfa Copyright (c) 2021 AWINASH KUMAR, Pradip Lingfa Pradip Lingfa https://spast.org/techrep/article/view/2450 Wed, 13 Oct 2021 00:00:00 +0000 Improvement on Tensile Properties of Epoxy Resin Matrix Sugarcane Fiber and Tamarind Seed Powder Reinforced Hybrid Bio-Composites https://spast.org/techrep/article/view/1811 <p>Nowadays, hybrid bio-composites are being developed by combining different natural resources as reinforcement and filler components, and this has raised their necessary qualities dramatically. Sugarcane fibre and tamarind seed powder particles added to an epoxy resin matrix to test the material's tensile strength were the focus of this study. A reinforcing material is sugarcane fibre, while filler components include tamarind seed powder particles. Different reinforcement and filler materials were used to make hybrid bio-composite specimens while the epoxy resin weight percentage was maintained constant. Utilizing the hot press compression moulding technology, hybrid bio-composite boards were manufactured from start to finish. Water jet machining is used to remove hybrid bio-composite specimens for compression tests in accordance with ASTM standards from the hybrid bio-composite boards. It has been shown in experiments, for example, that adding tamarind seed powder particles to a sugarcane fiber/epoxy resin matrix considerably increases the hybrid bio-composites' tensile characteristics.</p> Mayakannan Selvaraju, Jayaraman.R, Girimurugan.R, Suresh.V, Shilaja.C Copyright (c) 2021 Mayakannan Selvaraju, Jayaraman.R, Girimurugan.R, Suresh.V, Shilaja.C https://spast.org/techrep/article/view/1811 Sat, 09 Oct 2021 00:00:00 +0000 A Comparative Study of Experimental and Theoretical Structural Analysis of Lithium Doped Nickel Oxide Nanoparticles https://spast.org/techrep/article/view/1851 <p>Li<sub>(x)</sub>Ni<sub>(1-x)</sub>O (x = 0.01, 0.02 and 0.03) samples were synthesized via sol-gel process. Experimental techniques such as X-ray diffraction (XRD) and Transmission Electron Microscope (TEM) were used for structural study of the fabricated materials. Theoretical structural analysis of samples also has been done using various models like Williamson Hall Plot-Uniform Deformation (WH-UDM) Model, Size-Strain (SSP) Plot and Halder-Wagner (H-W) Plot. Different physical and micro-structural parameters such as crystallite size and lattice strain of Li<sub>(x)</sub>Ni<sub>(1-x)</sub>O particles have determined by both experimental and theoretical models [Table 1]. A significant comparative study of calculated parameters has shown in this paper. The mean crystallite size using Scherrer’s Method has been found to be 21.66 nm, 20.09 nm and 19.25 nm for Li<sub>(x)</sub>Ni<sub>(1-x)</sub>O (0.01, 0.02 and 0.03) respectively. These calculated crystallite sizes are in agreement with the TEM results and theoretical models of W-H UDM plot, H-W plot, and W-H plot respectively [Fig.1]. The crystallite size of samples decreases (Li<sub>0.01</sub>Ni<sub>0.99</sub>O &gt; Li<sub>0.02</sub>Ni<sub>0.98</sub>O &gt; Li<sub>0.03</sub>Ni<sub>0.97</sub>O) with increase in lithium contents. Further, the strain values by SSP and H-W Plot are comparable with result obtained from TEM analysis. From the results analysis, calculation of crystallite size from W-H UDM plot and strain from SSP plot is more reliable among all the other methods as data points are comparatively nearby the slope. The estimated crystallite size from all the described method has been found in nano particle ranges, which is accurately confirming the formation of synthesized materials. The calculation of the crystallite size and induced strain of doped metal oxides is quite challenging due to limited reported research work [1-4]. The&nbsp; experimental and theoretical structural study of lithium doped nickel oxide nanoparticles is noteworthy, since structural confirmation enhances the use of these materials for applications in various fields like supercapacitor, batteries, shielding, sensor, electrochromic device and catalyst etc [5-8].</p> <p><img src="https://spast.org/public/site/images/anupama_bhankhar/ictsgs-pic.jpg" alt="Fig.1. Comparison of calculated crystallite size of synthesized samples using different XRD analysis by various methods" width="375" height="311"></p> <p><strong>Fig.1. </strong>Comparison of calculated crystallite size of synthesized samples using different XRD analysis by various methods</p> <p><strong>Table 1: </strong>Estimated physical parameters of synthesized samples by different methods</p> <table width="936"> <tbody> <tr> <td rowspan="2" width="143"> <p><strong>Series </strong></p> <p><strong>Ni<sub>(1-x)</sub>Li<sub>(x)</sub>O </strong></p> <p><strong>(x = 0.01, 0.02 and 0.03)</strong></p> </td> <td colspan="2" width="152"> <p><strong>Scherrer’s Method</strong></p> </td> <td colspan="2" width="144"> <p><strong>Modified Scherrer’s Method</strong></p> </td> <td colspan="2" width="115"> <p><strong>W-H Plot</strong></p> <p><strong>(UDM)</strong></p> </td> <td colspan="4" width="158"> <p><strong>SSP</strong></p> </td> <td colspan="2" width="144"> <p><strong>H-W Plot</strong></p> </td> <td width="72"> <p><strong>TEM</strong></p> </td> <td width="7"> <p>&nbsp;</p> </td> </tr> <tr> <td width="76"> <p><em>D</em></p> <p><em>(nm)</em></p> </td> <td width="76"> <p><em>ε x10<sup>-3</sup></em></p> </td> <td width="117"> <p><em>D</em></p> <p><em>(nm)</em></p> </td> <td colspan="2" width="76"> <p><em>D</em></p> <p><em>(nm)</em></p> </td> <td colspan="2" width="72"> <p><em>ε x10<sup>-3</sup></em></p> </td> <td width="76"> <p><em>D</em></p> <p><em>(nm)</em></p> </td> <td width="72"> <p><em>ε x10<sup>-3</sup></em></p> </td> <td colspan="2" width="76"> <p><em>D</em></p> <p><em>(nm)</em></p> </td> <td width="72"> <p><em>ε x10<sup>-3</sup></em></p> </td> <td colspan="2" width="79"> <p><em>D</em></p> <p><em>(nm)</em></p> </td> </tr> <tr> <td width="143"> <p><strong>Ni<sub>0.99</sub>Li<sub>0.01</sub>O</strong></p> </td> <td width="76"> <p>20.42</p> </td> <td width="76"> <p>4.14</p> </td> <td width="117"> <p>18.86</p> </td> <td colspan="2" width="76"> <p>40.52</p> </td> <td colspan="2" width="72"> <p>1.53</p> </td> <td width="76"> <p>47.09</p> </td> <td width="72"> <p>10.79</p> </td> <td colspan="2" width="76"> <p>42.88</p> </td> <td width="72"> <p>10.08</p> </td> <td colspan="2" width="79"> <p>45.33</p> </td> </tr> <tr> <td width="143"> <p><strong>Ni<sub>0.98</sub>Li<sub>0.02</sub>O</strong></p> </td> <td width="76"> <p>18.03</p> </td> <td width="76"> <p>2.00</p> </td> <td width="117"> <p>16.57</p> </td> <td colspan="2" width="76"> <p>34.09</p> </td> <td colspan="2" width="72"> <p>2.08</p> </td> <td width="76"> <p>40.38</p> </td> <td width="72"> <p>13.65</p> </td> <td colspan="2" width="76"> <p>30.07</p> </td> <td width="72"> <p>9.28</p> </td> <td colspan="2" width="79"> <p>35.66</p> </td> </tr> <tr> <td width="143"> <p><strong>Ni<sub>0.97</sub>Li<sub>0.03</sub>O</strong></p> </td> <td width="76"> <p>18.57</p> </td> <td width="76"> <p>4.55</p> </td> <td width="117"> <p>16.75</p> </td> <td colspan="2" width="76"> <p>30.22</p> </td> <td colspan="2" width="72"> <p>2.04</p> </td> <td width="76"> <p>36.07</p> </td> <td width="72"> <p>12.99</p> </td> <td colspan="2" width="76"> <p>29.79</p> </td> <td width="72"> <p>11.04</p> </td> <td colspan="2" width="79"> <p>31.45</p> </td> </tr> </tbody> </table> <p>&nbsp;</p> Anupama, Monika Saini, Swati, Rajni Shukla Copyright (c) 2021 Anupama, Monika Saini, Swati, Rajni Shukla https://spast.org/techrep/article/view/1851 Fri, 08 Oct 2021 00:00:00 +0000 A Comparative Study of Experimental and Theoretical Structural Analysis of Lithium Doped Nickel Oxide Nanoparticles https://spast.org/techrep/article/view/1694 <p>Li<sub>(x)</sub>Ni<sub>(1-x)</sub>O (x = 0.01, 0.02 and 0.03) samples were synthesized via sol-gel process. Experimental techniques such as X-ray diffraction (XRD) and Transmission Electron Microscope (TEM) were used for structural study of the fabricated materials. Theoretical structural analysis of samples also has been done using various models like Williamson Hall Plot-Uniform Deformation (WH-UDM) Model, Size-Strain (SSP) Plot and Halder-Wagner (H-W) Plot. Different physical and micro-structural parameters such as crystallite size and lattice strain of Li<sub>(x)</sub>Ni<sub>(1-x)</sub>O particles have determined by both experimental and theoretical models [Table 1]. A significant comparative study of calculated parameters has shown in this paper. The mean crystallite size using Scherrer’s Method has been found to be 21.66 nm, 20.09 nm and 19.25 nm for Li<sub>(x)</sub>Ni<sub>(1-x)</sub>O (0.01, 0.02 and 0.03) respectively. These calculated crystallite sizes are in agreement with the TEM results and theoretical models of W-H UDM plot, H-W plot, and W-H plot respectively [Fig.1]. The crystallite size of samples decreases (Li<sub>0.01</sub>Ni<sub>0.99</sub>O &gt; Li<sub>0.02</sub>Ni<sub>0.98</sub>O &gt; Li<sub>0.03</sub>Ni<sub>0.97</sub>O) with increase in lithium contents. Further, the strain values by SSP and H-W Plot are comparable with result obtained from TEM analysis. From the results analysis, calculation of crystallite size from W-H UDM plot and strain from SSP plot is more reliable among all the other methods as data points are comparatively nearby the slope. The estimated crystallite size from all the described method has been found in nano particle ranges, which is accurately confirming the formation of synthesized materials. The calculation of the crystallite size and induced strain of doped metal oxides is quite challenging due to limited reported research work [1-4]. The&nbsp; experimental and theoretical structural study of lithium doped nickel oxide nanoparticles is noteworthy, since structural confirmation enhances the use of these materials for applications in various fields like supercapacitor, batteries, shielding, sensor, electrochromic device and catalyst etc [5-8].</p> Anupama Copyright (c) 2021 Anupama https://spast.org/techrep/article/view/1694 Fri, 08 Oct 2021 00:00:00 +0000 A plant-mediated synthesis and antibacterial activity of hydroxyapatite from cuttlefish bone for bone related applications https://spast.org/techrep/article/view/2953 <p>The green synthesis of hydroxyapatite nanoparticles (HAp) via biogenic sources has received<br>great attention towards biomedical applications in recent years. The regents used for the<br>synthesis of HAp through the conventional method are not eco-friendly, very costly, and the<br>structure does not resemble natural bone. To avoid the problem caused by the conventional<br>method, the plant-mediated synthesis of HAp from biogenic sources is considered more<br>attractive by researchers because of its superior properties such as non-toxic, cost-effective,<br>and resemblance to natural bone, which improves longevity and life span of humans. In<br>the present study, the hydroxyapatite was prepared by green synthesis from the precursor of<br>calcium oxide obtained from the cuttlefish bone using three different plant extracts like<br>Azadirachta Indica, Eucalyptus Globulus, and Cissus Quadrangularis [1]. The synthesized<br>hydroxyapatite was characterized by various techniques such as X-ray powder diffraction<br>(XRD), Fourier transform infrared spectroscopy (FT-IR). The FTIR study confirms the<br>various functional groups present in HAp. The XRD analysis confirms the hexagonal<br>structure of the HAp. Titanium alloy is emerging as the most promising material in the<br>biomedical field [2]. The synthesized HAp nanoparticle was coated on the Ti6Al4V alloy<br>using an electrodeposition method. Electrochemical analysis was carried out for the coated<br>and pristine sample using SBF solution at the temperature of 370C using the cyclic<br>voltammetric method [3]. The surface morphology of the coated sample was characterized by<br>FESEM, EDAX, and AFM. The corrosion resistivity of the sample was improved from<br>pristine to different HAp coated samples. The antibacterial property of the sample was tested<br>against two different pathogenic bacterial strains, Staphylococcus aureus, and Escherichia<br>coli. The HAp coated Ti6Al4V alloy was exhibiting more attractive properties than the<br>pristine sample and this may be used as a better candidate for bone-related applications.</p> M. KALPANA, NAGALAKSHMI R Copyright (c) 2021 M. KALPANA, NAGALAKSHMI R https://spast.org/techrep/article/view/2953 Fri, 05 Nov 2021 00:00:00 +0000 Bio-polyurethane foam for fire retardant applications https://spast.org/techrep/article/view/875 <p>Polyurethane (PU) is a material that finds applications in numerous sectors such as construction, automotive, furniture, additives, and so on. It has been forecasted that the global market for PUF will reach around 12.7 million tons by the year 2024, thus implying its high demand. Conventional polyurethane is synthesized using a mixture of polyols originating from fossil fuels and isocyanate. Wastes from Polyurethane Foam (PUF) are classified as white pollution, and they will have an impact on the living environment. At the same time, since the density of PUF is low, stockpiling will also take up a lot of space [1]. The pliable nature of PUF stems from a wide array of attributes that can be attained by tweaking the composition while manufacturing PUF. To control the quality of the foam, it is necessary to change the type and content of the isocyanate, polyol, catalyst, surfactant, blowing agent, and additive(s). In recent times the demand for green, sustainable, and non-toxic materials is rising due to environmental awareness and stricter policies. This resulted in the birth of Bio-PUF. In addition, the use of a fire-retardant additive can adversely affect the mechanical properties of the PUF. This necessitates the need for incorporating certain components into the rigid backbone of the PUF to counteract the adverse effects. Recent advances in this study include incorporating a phosphorus moiety to enhance the fire-retardant nature of Bio-PUF.</p> <p>Broadly, the Bio-PUF production process can be segregated into three classes based on the reagents used. These reagents are vegetable oil, lignin, and non-isocyanate-based.&nbsp; Vegetable oils possess a high degree of unsaturation, which makes them suitable for synthesizing polyols. Lignin, an abundant biopolymer exhibit attributes including UV protection, flame retardancy, and hydrophobicity [2].&nbsp; Non-iso-cyanate-based methods lead to the most environmentally friendly PUFs. Recent studies have depicted the use of dispersion technology [3] and carbon allotropes to increase the mechanical strength of Bio-PUF [4].</p> <p>This review consolidates the research in the field of bio PUFs as depicted in figure 1 and identifies the gaps/challenges in the synthesis of Bio-PUFs. Also, the recent technologies, different applications, and environmental impact of Bio-PUF in comparison with the standard PUF are discussed.</p> Ujwal Shreenag Meda, Haritha R, Harshitha N, Sripriya U Copyright (c) 2021 Ujwal Shreenag Meda, Haritha R, Harshitha N, Sripriya U https://spast.org/techrep/article/view/875 Thu, 16 Sep 2021 00:00:00 +0000 Porous Polymer Monoliths as Adsorptive Host Template for CeO2-CaO Nanocomposite Dispersion for Visible Light Heterogeneous Photocatalysis https://spast.org/techrep/article/view/234 <p>In this work, we report on the synthesis of CaO doped CeO<sub>2</sub> nanocomposites (NCs) prepared by a sonochemical-assisted temperature-controlled hydrothermal method. Considering the toxicity and recovery issues associated with nano-particles/composites, a novel approach has been attempted through the uniform dispersion of the CeO<sub>2</sub>-CaO NCs across a macro-/meso-porous polymer monolith template <strong>[1]</strong>. The structural and morphological properties of the synthesized photocatalyst materials have been monitored by p-XRD, FE-SEM-EDAX, HR-TEM-SAED, XPS, FT-IR, UV-Vis-DRS, PLS, and BET analysis. The visible-light photocatalytic performance is monitored using varying stoichiometric ratios of CeO<sub>2</sub>-CaO NCs with best results achieved using, 20 wt.% CaO doped CeO<sub>2</sub> NCs that are homogeneously dispersed on a 3D network of the porous polymer monolithic network. The CeO<sub>2</sub>-CaO NCs dispersed polymer monolith reveals superior photocatalytic activity in comparison to CaO doped CeO<sub>2</sub> NCs that are likely to agglomerate in aqueous solutions that eventually reduce their process efficiency. The CeO<sub>2</sub>/CaO NCs dispersed polymer monolith exhibit excellent porosity and surface area, for the ultra-fast dissipation of organic molecules, apart from being durable and reusable. For photocatalysis studies, we have chosen an antimicrobial drug namely moxifloxacin, for the visible-light-induced dissipation, to counter the problems associated with the emergence of resistant bacteria. We hereby state that the prepared monolithic NCs are easy to synthesize, cost-effective, and reusable, thus making them an ideal heterogeneous photocatalyst for pollutant dissipation.</p> Satya Prasad A Copyright (c) 2021 Satya Prasad A https://spast.org/techrep/article/view/234 Thu, 09 Sep 2021 00:00:00 +0000 Advanced Hybrid solid propellant for futuristic missile technology https://spast.org/techrep/article/view/1982 <p>In Today’s time the rocket engines for the missiles generally depend on the cryogenic and liquid propellants because of their high Specific Impulses (ISP ~ 450s) and control. The cryogenics have a major issue of storage and handling. Over the past few years, the dependence on the cryogenic propellants {i.e., fuel-&gt; Liquid Hydrogen(H)(L) and oxidizer- &gt;Liquid Oxygen (O<sub>2</sub>)(L)} is increasing at a very high pace.</p> <p>Hybrid Solid propellants provide a good alternative to these. This project, is aimed to enhance the performance of rocket engine by increasing the ISP of the propellants by using various energetic materials {that are readily available}, and varying proportions of fuel &amp; oxidizer to obtain a new composition that can be prepared in a room temperature to create a Hybrid Solid Propellant.</p> <p>Current work is driven by the need to reduce the overdependency on liquid and cryogenic propellants, and find an alternative to these propellants. The performance is evaluated in terms of Specific impulses (I<sub>SP</sub>) and Characteristic velocity (c*) both of which are significant parameters.</p> <p>NASA Cea software will be used extensively to find out the I<sub>sp</sub> and characteristic velocity for the different proportions of energetic catalyst. Then the graphs will be plotted for all the values. Characteristic velocity is a design parameter which will be used to validate the data and I<sub>sp</sub> values.</p> <p>The combinations which both increase and lower the I<sub>sp</sub> to very high levels are useful. The combinations with higher I<sub>sp</sub> will increase the thrust to high levels which will make the missile faster and harder to intercept. Combinations which reduce the I<sub>sp</sub> drastically to very low levels will help to make missiles reusable as after injecting the specific catalyst they can be guided slowly back to the surface instead of carrying out the self-destruct procedure.</p> <p>Solid propellants currently in use or available easily do not have such high I<sub>sp</sub> which will make them suitable for the missiles of the future. Those missiles will need high energy propellants to be effective. Due to this fact existing solution is liquid or cryogenic propulsion. This research work will help discover a new propellant which can replace this high performance but expensive types of fuels. Additional to the cost is the problem of storing the chemicals especially cryogenic fuels which need very low temperatures to keep them fit for use. Solid propellants can be stored at relatively higher temperatures and are easier and safer to handle and transport.</p> <p>Thus, this research work will help reduce the cost which goes in the development of storage facilities and transportation arrangements of the propellants for missiles. Although the scope of the research is aimed at making missile technology more attractive and viable it is not limited to missiles. The advantages mentioned above hold true even for rocket technology as missiles are a part of rocket family because both use rocket engines.</p> Abhijoy Ganguly, Apoorv Kumar Copyright (c) 2021 Abhijoy Ganguly, Apoorv Kumar https://spast.org/techrep/article/view/1982 Sat, 09 Oct 2021 00:00:00 +0000 Corrosion Inhibition effect of Zinc Oxide nanoparticles coated on mild steel by Flame techniques https://spast.org/techrep/article/view/2098 <p>Unlike spray pyrolysis and combustion methods an alternate method of nano coating called flame coating technique has been proposed, which forms a stable and an adherent coating on the metal substrates. On introducing the zinc sulphate incorporated Polyvinyl Alcohol (PVA) polymer film into the flame, nano zinc oxide gets coated over the mild steel substrate. The ZnO nanocoating (anodic to steel) suppresses the corrosion nature of steel thereby shifting the corrosion potential (Ecorr) towards positive side. Electrochemical polarisation results taken for the ZnO coated steel (Ecorr = -0.5462V Vs Ag/AgCl) is positive than uncoated steel specimen&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; (Ecorr = -0. 558V). Corrosion resistant behaviour of ZnO coated steel has also been substantiated from the weight loss studies and electrochemical impedance spectroscopy analysis. Morphology of the ZnO coated mild steel specimens were examined using SEM and the coatings thus obtained were uniform in nature and highly adherent to the mild steel substrate. The characteristics of as deposited ZnO were analyzed from its XRD pattern and FTIR spectra.</p> Pandiyarasan Veluswamy Copyright (c) 2021 Pandiyarasan Veluswamy https://spast.org/techrep/article/view/2098 Fri, 08 Oct 2021 00:00:00 +0000 Current Concepts and Use of Human Cord Blood Platelet Rich Plasma Therapy in Regenerative Endodontic Treatment https://spast.org/techrep/article/view/2132 <p>Platelet-rich plasma (PRP) containing growth factors has gained popularity as a biomaterial for regenerative medicine in the past few years. PRP, which is a physiological biomaterial that comprises a variety of platelet-derived growth factors, is predicted to act on numerous growth factors that are necessary for histogenesis (1) without the artificial activation of a single growth factor. PRP promotes tissue regeneration through a combination of activities mediated by several types of growth factors produced by concentrated platelets(2). PRP has been researched as a method of delivering growth factors to a wound healing site in order to enhance tissue regeneration(3). Different concentrations of PRP samples produced from umbilical cord blood PRP contained considerably greater amounts of PDGF-AB/BB and FGF-2, both of which have well-documented implications on mesenchymal stem cell proliferation(4). The important growth factors in Umbilical Cord Blood-PRP are: 1) platelet-derived growth factorBB (PDGF-BB)dan MSC proliferation accelerator; 2) transforming growth factor b1 (TGF-b1) of TGF-b superfamily that is similar in structure to BMP-an extracellular matrix production accelerator; and 3) vascular endothelial growth factor (VEGF)-an angiogenesis accelerator(5) various studies have reported that these molecules produced from PRP comprise biomolecules and growth factors that are found in tears and are crucial for corneal healing. On a human epithelial corneal cell line, they stimulate cell migration and proliferation while having no cytotoxic effects. Moreover, they also inhibit the activation of NK and CD8+ T cells in vitro(6). Umbilical Cord Blood has been demonstrated to be substantially more effective in promoting IL-10 (anti-inflammatory cytokine) protein synthesis while inhibiting IL-12 (a pro-inflammatory cytokine) protein synthesis than peripheral blood PRP(7). PRP is known to include growth factors such as PDGF and TGF, which are crucial in hard and soft tissue regeneration, plastic surgery, and sports injuries to regenerate vascular tissue and serve as a scaffold during post-operative repair and regeneration.</p> <p>PRP has been proposed to play a beneficial effect in tissue regeneration. PRP has been researched in the dentistry industry as a possible way to provide growth factors to a wound healing site to enhance tissue regeneration. Moreover, the use of PRP prepared from a patient’s own blood will likely reduce harmful immune responses. If adult PRP is not available, umbilical cord blood PRP can even be adopted instead, with the expectation of similar effects on cell proliferation and migration in the regeneration of tissues. Significant increases in MSC proliferation and migration were observed using umbilical cord PRP as compared to adult PRP, likely due in part to greater amounts of PDGF and FGF between the blood sources. PRP generated from umbilical cord blood also contained greater amounts of VEGF, a key molecule in the promotion of angiogenesis and neovascularization. In contrast, PRP derived from adult peripheral blood contained more SDF-1, a chemokine demonstrated in multiple previous reports to stimulate chemotaxis of mesenchymal stem cells(8).</p> <p>Apexification treatments employing calcium hydroxide to stimulate apical hard tissue barrier generation or apical MTA plugs before root canal filling are routinely used to treat immature permanent teeth with necrotic pulp/apical periodontitis. Apexification offers the little potential of restoring the viability of injured tissue in the canal space or promoting root maturation (thinner root canal walls and/or apical closure) in immature permanent teeth with necrotic pulp. The American Association of Endodontics counsels using regenerative endodontic therapy in immature teeth with necrotic pulp(9). In the canal space, regenerative endodontics uses the trio of tissue engineering, stem cells, biomimetic scaffold, and bioactive growth factors to repair pulp tissue that has been destroyed by infection, trauma, or developmental abnormalities. Platelet-rich plasma was proven to be effective in promoting apical closure and root development in immature permanent teeth when used in regenerative endodontic treatment. Proliferation, migration, and mineralization were all preferred in dental pulp stem cells grown with a specific concentration of PRP. Stem cells from Human Exfoliated Deciduous teeth cultured with PRP displayed a high concentration of odontogenic markers such as dentin matrix protein 1 and dentin sialo phosphoprotein(10). Platelets comprise mitogenic growth factors and chemicals that stimulate tissue healing and angiogenesis, according to research. As a result, in the instance where adult PRP is unavailable, Umbilical Cord Blood PRP might be administered with the expectation of getting similar effects on cell proliferation and migration, which are required for wound healing and tissue regeneration. Proliferation and osteogenic differentiation of stem cells from human exfoliated deciduous teeth, dental pulp stem cells, and periodontal ligament stem cells may be enhanced by Umbilical Cord Blood-PRP(11). Since the literature have shown that umbilical cord blood-PRP has an inductive effect in the regenerative cells in dental tissue, it can be used as an alternative biomaterial in regenerative endodontics especially in the pediatric population and in individuals with blood dyscrasias.</p> Serene Joy Copyright (c) 2021 Serene Joy https://spast.org/techrep/article/view/2132 Fri, 08 Oct 2021 00:00:00 +0000 A Review on recent advancement in Radar Absorbing Materials for Stealth Technology https://spast.org/techrep/article/view/1588 <p>Radar absorbing materials are designed to absorb radar waves and to minimize or eliminate reflection. The absorbed energy by the materials is then converted to heat. As these radar waves are not returned, a radar absorbing material (RAM) provides a reduced signature for detection and finds a potential application in Stealth Technology. Not only in defence but also stealth technology is used in defence as well as in commercial applications. Stealth is a technology that makes the object less visible. Now, the key question arises here is how this stealth technology helps in reducing the visibility. In this review, we will be discussing stealth technology, what are radar absorbing materials (RAM) and also elucidate the mechanism of ‘radar absorbing’ by RAM. RAM is used as coatings on aircraft, missiles, etc. and as it is used in aircraft applications it should be lighter in weight and should also possess good thermal and mechanical strength. To obtain such properties, porous ceramics are developed using the barium titanate and it has found to be suitable owing to its a high dielectric constant [1]. The result shows porous barium titanate is one of the best coating materials that can be used as RAM. Composites are also seen as one of the most promising materials for radar absorption. As composites are made by using two or more materials, so materials are selected in such a way that they overcome the deficiency of the other material, and after synthesizing they become the good absorbent of waves. One such composite is made using milled carbon fibres, discontinuous aluminosilicate fibres, and silicon resin as a matrix [2]. As carbon fibres &nbsp;are high-strength materials, they are used for the reinforcement. Aluminosilicate having low thermal conductivity with heat resistance up to 1000 &nbsp;and silicon resin matrix exhibiting good thermal and chemical stability are used for the fabrication of RAM. There are many more materials that are used as radar absorbing material like porous ceramic with carbon, Fe<sub>3</sub>O<sub>4 &nbsp;</sub>polymer, cellulose-chitosan/PANI aerogel, etc. Magnetite polymer combined with epoxy resin also constitutes RAM [3]. Magnetite has a high magnetizing property which results in high absorption of radar waves. Cellulose with a three-dimensional (3D) structure was synthesized with polyaniline (PANI) conducting polymer cladding on its surface which has good electromagnetic waves absorbing property as well as good thermal insulation application [4].</p> Prakhar Sharma Copyright (c) 2021 Prakhar Sharma https://spast.org/techrep/article/view/1588 Fri, 01 Oct 2021 00:00:00 +0000 Optimization of growth parameters of thermal chemical vapour deposition method for 2D MoS2 synthesis https://spast.org/techrep/article/view/574 <p>Two dimensional layered materials have fascinated scientist after successful exfoliation of graphene. Transition metal dichalcogenides are considered to be perfect successor of graphene as they overcome shortcomings of graphene like zero bandgap and control over the number of layers [1-3]. MoS<sub>2</sub> has been extensively explored among transition metal dichalcogenides due to its unique chemical and physical properties [4]. Still, it is quite challenging to obtain high quality MoS<sub>2 </sub>films using a controlled synthesis technique. Out of all the available methods like hydrothermal synthesis, mechanical exfoliation, thermal CVD, liquid exfoliation etc. chemical vapour deposition has proven to be a reliable technique to produce MoS<sub>2</sub> thin films [5]. Depending on various conditions, monolayer to few-layer to multilayer MoS<sub>2</sub> can be synthesized using this method. The CVD growth process is sensitive to variety of parameters involved in the process such as temperature, gas flow, pressure, precursor concentration, position of substrate, nature of substrate etc. It is so sensitive that even if we change one parameter by a little amount the results vary drastically. In the present work, we report the effect of pressure, temperature, gas flow, position of substrate on the growth of MoS<sub>2</sub> films [6]. After several failures, the technique is optimized to synthesize high quality MoS<sub>2 </sub>films on quartz substrate. The block diagram for cvd process optimization is represented in fig.1.</p> <p>The films are characterized using XRD, UV-Vis spectroscopy, photoluminescence spectroscopy and raman spectroscopy. Main objective of this work is to device a method that produces MoS<sub>2 </sub>films using thermal CVD process by optimizing various parameters so that further research on applications of MoS<sub>2</sub> can be carried out rather than focusing on finding best synthesis method for particular application. It finds application in electronics particularly in sensors like biosensors, optical sensors, electrochemical biosensors that can help in detecting deadly diseases like cancer and Alzheimer [7]. MoS<sub>2</sub> has an extensive range of applications in energy resources like microwave, solar cells and batteries applications. It has potential to be used in magnetoresistance and spintronics [8]. The thin films obtained using this method can be explored for further applications in various field and it will help in boosting the research in many fields.</p> <p><strong><img src="https://spast.org/public/site/images/aroraanmol/graphical.jpg" alt="" width="960" height="720"></strong></p> <p><strong>Fig.1.</strong> Block diagram of optimization process</p> Anmol Arora, Kriti Sharma, S.K. Tripathi Copyright (c) 2021 Anmol Arora, Kriti Sharma, S.K. Tripathi https://spast.org/techrep/article/view/574 Sun, 19 Sep 2021 00:00:00 +0000 Growth of ZnO 2D layers by Atomic Layer Deposition (ALD) and study of its physical properties for photovoltaic and photoconvertor device applications https://spast.org/techrep/article/view/2290 <p>Zinc oxide (ZnO) is direct bandgap semiconductor material. It has a wide bandgap of 3.37eV at room temperature. ZnO belongs to the II-VI semiconductor group. It possesses properties like high electron mobility, good transparency and luminescence at room temperature. At ambient temperature conditions, it is thermodynamically stable in the wurtzite hexagonal structure. ZnO has very interesting electrical and optical properties which make it a suitable contender among various semiconductor materials for various electronic and optoelectronic devices. ZnO is widely used for fabricating solar cells, LEDs, UV photodetectors, gas sensors, transparent conductors, varistors, piezo-electric transducers and many other such applications. ZnO is intrinsically n-type semiconductor which is considered due to zinc interstitials or oxygen vacancies. Reliable p-type doping of ZnO is difficult to achieve therefore fabricating ZnO based homojunctions is difficult. Heterojuctions structures of ZnO with various p-type substrates are fabricated such as SiC, GaN, NiO, AlGaN, Si etc but these structures come down with low efficiencies. ZnO is an n-type semiconductor with numerous intrinsic defect levels responsible &nbsp;for the electrical and optical behaviors but the origin of those defects is a controversial subject among researchers. ZnO thin films can be deposited by different methods viz. thermal evaporation &nbsp;and sol-gel methods[1]. The problem with these methods is that sometimes crystallites don’t have any preferred orientation <strong>[1]</strong>. Moreover, ZnO thin films deposited by sol-gel method need to be preheated and annealed at high temperatures to have favorable growth orientation <strong>[2]</strong>. All these methods either need high temperature deposition or post deposition annealing to facilitate the formation of thermodynamically stable wurtzite structure of ZnO in films. In the present work, 2D layers of ZnO &nbsp;of three different thicknesses were deposited by atomic layer deposition (ALD) technique. These These layers were deposited on corning glass substrates. ALD is a novel deposition technique suitable for nanotechnology engineering generally for low temperature deposition. ALD is a thin film deposition technique based on the sequential use of gas phase chemical process. This provides unique features such as precise control of ZnO 2D layer thickness with atomic resolution, high uniformity, good conformity and high aspect ratio. Using this technique ZnO thin films were deposited with precision under optimized conditions using diethyl zinc (DEZ) as the precursor for zinc and ozone gas (O<sub>3</sub>) as oxygen source. Nitrogen (N<sub>2</sub>) was used as purging gas in deposition procedure. A schematic of an ALD cycle is shown in <strong>Fig.1</strong>. By repeating the number of cycles, ZnO films of three different thicknesses were deposited. In order to study the quality of the deposited ZnO 2D layers, the physical, electrical and optical properties were investigated by different material characterization techniques. The optical properties of ZnO 2D layers were investigated by UV-Visible Spectroscopy and Photoluminescence Spectroscopy (PL). The structural and morphological properties were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM) and Raman Spectroscopy. The electrical characterization was performed using hall effect measurement. The ZnO thin films were deposited at 150 <sup>o</sup>C substrate temperature. The ZnO films deposited by ALD method at low temperature showed preferred orientation in XRD plots. The intensity of (002) peak increased considerably with increasing thickness of ZnO 2D layers as shown in <strong>Fig 2</strong>. The films were oxygen rich in nature having high O/Zn ratio. The films showed improved crystallite size and uniformity with increasing thickness. The films were transparent in nature with bandgap values higher than bulk value 3.37 eV. Thus, this study contributes in understanding the fundamentals involved in deposition of ZnO 2D -layers by ALD deposition technique and discovering the potential use of these films for fabricating solar cells, gas sensors and many other such applications.<img src="https://spast.org/public/site/images/nareshpadha123/fig-2-zno.jpg" alt="" width="1163" height="1646"></p> NARESH PADHA Copyright (c) 2021 NARESH PADHA https://spast.org/techrep/article/view/2290 Thu, 07 Oct 2021 00:00:00 +0000 A Novel Electrospun PU@CuS Hybrid Nanofiber Composite: Synthesis and Morphology Characterization https://spast.org/techrep/article/view/81 <p>Till date, materials researchers are facing the major challenge for effective processing of nanocomposites with polymeric matrix with satisfactory dispersion of the nanometric phase, as well as a suitable interface between the polymer phase and the nanoparticle. Polyurthane (PU), being most commercialized polymer finding its place in various engineering application such as mechanical, electronic, and biomedical&nbsp; field&nbsp; and found to be more useful in combination with inorganic nanoparticles.&nbsp; In this study we report the development and characterization of nano CuS embedded polyurethane fiber composite. The PU nanofibers were electrospun by optimizing the parameters namely, applied electric potential, concentration, flow rate. Scanning electron microscope (SEM) images of the PU nanofibres electrospun at 13kV, 1ml/h and 10wt% showed appearance of uniform mat having a fiber diameter of 175 nm. CuS nanoparticles were synthesized by hydrothermal method employing three types of surfactants. The effect of polar and non polar solvent on particle size and morphology has also been investigated. Further, the CuS embedded PU/CuS nanofiber composite was developed by electrospinning.</p> MANJUNATHA C, Sudeep M, Sham Aan M P, Ujwal Shreenag Meda Copyright (c) 2021 MANJUNATHA C, Sudeep M, Sham Aan M P, Ujwal Shreenag Meda https://spast.org/techrep/article/view/81 Mon, 23 Aug 2021 00:00:00 +0000 Effect of trisodium citrate as an intermediate at metal nanoparticle/aminoglycoside antibiotic interface https://spast.org/techrep/article/view/127 <p>For the efficient drug delivery/carrier system, silver and gold nanoparticles have been considered to be highly useful platform due to their well-studied synthesis, easy surface modification and biocompatibility and low toxicity [1]. These metal-antibiotic conjugates were reported to have encouraging applications against both Gram-positive and Gram-negative class of bacteria [2]. The spherical silver and gold nanoparticles (AgNPs/AuNPs) have been synthesized by chemical reduction method in the presence of trisodium citrate. The citrate anions stabilize metal nanoparticles through electrostatic mechanism [3, 4]. For the synthesis of AgNPs and AuNPs, trisodium citrate in the presence of reducing agent (NaBH<sub>4</sub>), were mixed with silver nitrate (AgNO<sub>3</sub>) and gold chloride (AuCl<sub>3</sub>), respectively. 10 mM (2 mL) of trisodium citrate was added to 1 mM of AgNO<sub>3</sub>&nbsp;and AuCl<sub>3</sub>. The solutions were left for 2 hours at room temperature under vigorous stirring for complete synthesis of citrate-AgNPs and citrate-AuNPs. &nbsp;Further, surfactant coated AgNPs and AuNPs have been functionalized with amikacin. antibiotic bound nanoparticles were prepared by stirring different concentrations (0.2 mM and 0.4 mM) of amikacin solution to constant volume of synthesized AgNPs/AuNPs (5 mL)) for 30 min followed by incubation for overnight at room temperature. Then, the resulting amikacin functionalized silver and gold nanoparticles (Amk@citrate-AgNPs/Amk@citrate-AuNPs) stored at low temperature in the dark. The role of trisodium citrate as a binder between drug and nanoparticle has been analyzed by using different analytical techniques such as UV-Visible absorption spectroscopy, and X-ray diffraction, DLS and FTIR. It has been observed that in case of AgNPs, citrate is not a good linker for amikacin to bind with nanoparticle surface as silver lost its SPR after the addition of amikacin. The reason is the formation of unstable compounds with AgNPs as citrate could not able to stabilize AgNPs completely (Fig.1(a)). However, Tween 20-AgNPs and PVP-AgNPs could be used as linker for amikacin due to their better stabilizing property than citrate. In case of AuNPs, citrate could be used as a linker between drug and nanoparticle surface. The XRD pattern has been recorded for bare and drug coated nanoparticles which also depicts the loading of amikacin on AuNPs with slight change in reflection lines (Fig. 1(b)). The measured Z-average size from dynamic light scattering before and after drug conjugation is another parameter that hints the binding of drug to gold nanoparticles surface. Fourier infrared transform spectroscopy results also infer the presence of hydrogen bond through secondary amide or amine group of amikacin and gold nanoparticles.</p> <p>&nbsp;</p> <p>&nbsp;</p> Amritpal Kaur Copyright (c) 2021 Amritpal Kaur https://spast.org/techrep/article/view/127 Tue, 24 Aug 2021 00:00:00 +0000 A comparative analysis of structural, optical and electrical properties of polyaniline/ferrite (Co, Ni, Cu, Zn) composites https://spast.org/techrep/article/view/1849 <p>&nbsp;&nbsp;&nbsp; &nbsp;Conducting polymers nanocomposites are proving to be useful materials as they are flexible as well as conducting with large surface to volume ratio[1,2]. Ferrites have supplementary properties with respect to polymers such as they are robust and magnetic in nature. Among the conducting polymers, Polyaniline commonly called PANI, is one of the most widely studied material hence its composite with&nbsp; ferrites will result in a new class of smart material [3]. In this study, PANI, PANI/Cobalt ferrite, PANI/Nickel ferrite, PANI/Copper ferrite and PANI/Zinc ferrite composites were studied. Polyaniline and their composites with ferrites (Co, Ni, Cu, Zn) were prepared via chemical oxidation polymerization method (Fig 1.). Ferrites were synthesized through co-precipitation method by using oleic acid to keep their size in nanometre range. The structural, optical and electric properties of fabricated materials have probed in detail. Structural properties were investigated using X-Ray diffraction spectroscopy (XRD) and Fourier Transform Infrared spectroscopy (FTIR) respectively. Pure ferrites were found to be of crystalline nature, whereas composites are found to be semi crystalline in nature [4]. Scanning electron microscope (SEM) analysis confirmed the formation of all the synthesized composites. The optical band gap of ferrites was calculated by UV-Vis spectroscopy (UV-Vis), is minimum for cobalt ferrite (1.1 eV) and increases for Ni (1.4 eV), Cu (1.3 eV) and Zn (1.9 eV) ferrites. The optical band gap of composites is reducing as compared to Pure PANI (1.7 eV), which is in agreement with already reported work [5]. The inclusions of ferrites particles have caused an enhancement in electrical conductivity of pure PANI [6]. Conduction mechanism observed from Nyquist plots of composites is found to involve both grain as well as grain boundaries. Among all the fabricated materials, different morphology of PANI/Cobalt ferrite composite is attributed in better conduction. The transition metal spinel ferrites have enhanced the optical and electric properties of PANI to a great extent, making them promising materials for different applications.</p> <p><img src="https://spast.org/public/site/images/swati_sehrawat/chemical-oxidation.jpg" alt=" Synthesis of Pani/Ferrite composites via chemical oxidation polymerization." width="802" height="526"></p> <p><strong>Fig.1. </strong>Synthesis of PANI/Ferrite composites via chemical oxidation polymerization.</p> Swati, Monika Saini, Anupama, Rajni Shukla Copyright (c) 2021 Swati, Monika Saini, Anupama, Rajni Shukla https://spast.org/techrep/article/view/1849 Fri, 08 Oct 2021 00:00:00 +0000 A Novel Manufacturing Process for Nanosilica carbide Reinforced Al2024 Matrix Composites https://spast.org/techrep/article/view/2928 <p>The flake powder metallurgy technique described in this paper is used to fabricate Al2024 matrix composites reinforced with SiC nanoparticles that are nearly net-shaped. These composites were tested to see what effect particle size had on the flake Al2024 matrix powders and how much SiC nanoparticles there were distributed throughout the particle distribution, microstructure, relative density, and hardness. Ball milling was used to combine the flake Al2024 matrix powders with three different sizes of as-received Al2024 powders. For example, the Al2024 matrix powders had a flake-like microstructure with dispersed SiC nanoparticles and grain boundaries that contained enough area for the reinforcement particles to be seen during microstructural characterization. There was an increase in hot-pressed density with decreasing matrix size due to frictional forces between the fine flake particles. Hardness increased as Al2024 matrix powder size decreased in Al2024/SiC nanocomposites.</p> N. Mohan Rajhu, C. Jayabalan, M. Siva, B. Ramesh Copyright (c) 2021 N. Mohan Rajhu, C. Jayabalan, M. Siva, B. Ramesh https://spast.org/techrep/article/view/2928 Sat, 23 Oct 2021 00:00:00 +0000 Wide band-gap and piezo-based power electronics for a sustainable future: A brief review https://spast.org/techrep/article/view/403 <p>Sources of the renewable energy system and transportation electrification are proven to be<br>the panacea of supporting sustainable development and countering the issues of climate<br>change. Power electronics equipment, being the integrated part of any renewable energy<br>system or any electrified transport systems (ETS), such as Electric Vehicles, are of prime<br>importance as the overall system efficiency can be improved by focusing on the efficiency of<br>power electronics equipment [1]. With time, new features are being added in ETS and loads<br>are also increasing in renewable energy systems, making the electrical burden increase<br>continuously. Silicon (Si), after ruling in the power electronics market for decades, has reached<br>a saturation level [2]. And to fulfill the requirements of a higher power level, silicon is not a<br>befitting candidate. In such a perspective, wide band-gap (WBG) devices have emerged as<br>an alternate player which has drawn the attention of the power electronics market. As the<br>name suggests, WBG devices (such as Gallium Nitride (GaN) and Silicon carbide (SiC)) have<br>wide band-gap energy and high breakdown voltage, which make them suitable for high power<br>application. Moreover, these devices have lower on-state resistance, better thermal<br>performance, lower output capacitance, and higher frequency than Si-based devices [3].<br>Because of such special features of WBG devices, these can be used to make the power<br>electronics equipment more efficient, of higher power density, and smaller size.<br>Another such material that helps the power electronics converters to be of higher efficiency,<br>higher power density, lighter weight, and smaller volume is a piezoelectric material.<br>Conventional magnetic energy storage components are the main hindrance to miniaturize<br>power electronics [4]. In this context, piezoelectric-based energy storage techniques (such as<br>piezoelectric transformers) give an alternative to power converters for energy storage. Piezobased<br>converters are promising for lightweight and miniature power electronics, which can be<br>used in sectors like healthcare and information technology. Additionally, this also gives an<br>option for soft switching and we don’t require other energy store components in such<br>converters.<br>In this article, both the WBG devices and piezoelectric for power electronics applications have<br>been investigated and reviewed based on their various characteristics, advantages, and<br>challenges. This review also serves as an article to find out the research gap in this field.</p> Mohit Bhardwaj, Param Copyright (c) 2021 Mohit Bhardwaj, Param https://spast.org/techrep/article/view/403 Thu, 16 Sep 2021 00:00:00 +0000 Short term Deflection of Three sides Fixed And One Side Simply Supported two way Slabs https://spast.org/techrep/article/view/2114 <p>Deflection is one of the serviceability limit states to be satisfied in the limit state design of structures. The computation of deflection of two way slabs at all load levels is complicated due to live loads, type of loading, span, modulus of elasticity of concrete, percentage of reinforcement in section, yield strength of steel, flexural strength of concrete, boundary condition, shrinkage, creep of concrete and non linear properties of the material. As a convinent way of controlling deflections, some codes of practice specify limiting span/depth ratio this is conservative because the effect of all factors affecting deflections is included in a single parameter i.e. depth. Clark et all [1] have compared the code clauses of different countries releated to deflection of concrete members.The ACI [2] manual of concrete practice recommend the procedure developed by branson based on beam test results for the computation of slab deflections.Desayi and Kulkarni [3] proposed methods for predicting load-deflection curves for restrained, partially restrained and simply supported rectangular two way slabs. Desayi and prabhakara [4] proposed a method for predicting load deflection curve for restrained skew slabs. Sarkar and Devdas Menon [5] estimated short-term deflections in two-way RC slabs using deflection coefficients .IS 456-2000 [6] only gives span-depth ratios of two way slabs for a span up to 3.5m, but doesn't clearly spell anything on the boundary conditions. EN1992 also gives span-depth ratio for UDL on slabs with various end. Deflection coefficients are available to predict the deflections of idealized boundary condition viz all sides simply supported, all sides fixed and certain mixed boundary conditions. However for three edges fully restrained and one long edge simply supported, closed form solutions are not come across. Hence an attempt has been made to apply the numerical technique which is a finite difference method for three edges fully restrained and one long edge simply supported case. This paper gives the results of an analytical method proposed to calculate short term deflection of High strength traditionally vibrated concrete (HSTVC) and high strength alkali activated concrete (HSAAC) slabs. A comparison has been made between the results of proposed method with various codes and experimental results. The result shows that the proposed method is able to predict the short term deflection satisfactorily with experimental results.</p> Shivaraj G Nayak shivu Copyright (c) 2021 Shivaraj G Nayak shivu https://spast.org/techrep/article/view/2114 Fri, 08 Oct 2021 00:00:00 +0000 Electrodeposition synthesis of cobalt-selenide as electrocatalyst for hydrogen evolution reaction https://spast.org/techrep/article/view/515 <p>The greenhouse effect and air pollution are mainly caused by carbon dioxide which is produced from fossil fuel, coal and natural gas consumption that was used in energy production [1]. Hydrogen energy is one of the alternative energies that has been considered as ideal clean energy and it is also a renewable source [2]. There are many methods to produce hydrogen energy. Among the methods, hydrogen production base on hydrogen evolution reaction (HER) in the electrochemical water splitting is well known as one of the most efficient systems [3]. The significant challenge for water splitting is to develop an active electrocatalyst, that can exhibit high stability, high current density and cost-effective for hydrogen evolution reaction. Generally, platinum is commonly most used as catalyst for the reduction reaction [4, 5]. However, their widespread applications are limited because their scarcity and excessive cost hinder their large-scale commercial applications.</p> <p>Transition metal chalcogenides (TMCs) are the most promising materials for electrocatalyst due to their adsorption property [2, 6]. However, the TMC catalysts are mostly in powder form. So, the catalyst powders need to be coated on the electrode for its application. This process usually uses binder polymer to attach TMCs on electrode surface but binder polymers such as polytetrafluoroethylene are insulating and electrochemical inert [7]. One possible way to improve the performance of the catalyst is directly growth on the supported electrode.</p> <p>Herein, the shaggy porous cobalt-selenide (Co-Se) (fig.1(A)) was used instead of platinum, the costly active electrocatalyst. The cobalt-selenide catalyst was directly grown on the synthesized carbon-based porous membrane via the optimized electrodeposition method. The as-prepared shaggy porous cobalt-selenide on carbon porous membrane was directly used as a binder free electrocatalyst for hydrogen evolution reaction. In this work, the porous membrane was first fabricated from cryogenic polymerization of gelatin and glutaraldehyde. Graphene oxide was also doped in the porous membrane to improve its conductive property [8]. After carbonization process, the conductive porous carbon membrane was obtained, and it was directly used as the template for electrodeposition of cobalt-selenide catalyst. The parameters for cyclic voltammetry and chronoamperometry electrodeposition methods were optimized for cobalt selenide synthesis. The concentration of plating solution was optimized for three ratios between Cobalt(II) and selenium(IV). The result showed that 1:1 ratio between Cobalt(II) and selenium(IV) provided the best catalytic efficiency.</p> <p>The electrochemical properties of electrocatalyst investigation were performed in three electrodes configuration electrolytic cell, including synthesized electrocatalyst, Ag/AgCl in 3.0M KCl, and platinum wire as working electrode, reference electrode, and counter electrode respectively (fig. 1 (B). The performance of hydrogen evolution reaction was performed in acidic (Ar-saturated 0.5 M H<sub>2</sub>SO<sub>4</sub>) aqueous electrolytes and linear sweep voltammetry technique was applied. The high electrochemical surface area was observed from the chemical double-layer capacitance (C<sub>dl</sub>) with cyclic voltammetry under non-faradaic region. The resistivity of synthesized electrocatalyst are measured from electrochemical impedance spectroscopy technique and it was found that the resistance of Co-Se electrocatalyst from chronoamperometry, cyclic voltammetry and bare electrode equal to 5.99 Ω, 83.36 Ω, 174.32 Ω, respectively. In this project, cobalt selenide electrocatalyst from the optimum condition exhibit overpotentials 116 mV and Tafel slope of 80.1 mV/dec for HER testing. The duration stability of catalysis was performed with chronoamperometry and the results provide no decreasing of cathodic current over 24 hours testing period.<img src="https://spast.org/public/site/images/aum_sittipong/fig.1-sem-and-her-electrolytic-cell.png" alt="Fig.1. SEM figure of Co-Se electrode (A) and HER electrolytic cell set up (B)." width="780" height="277"></p> <p>&nbsp;</p> <p>&nbsp;</p> Sittipong Kaewmorakot, Sujittra Poorahong Copyright (c) 2021 Sittipong Kaewmorakot, Sujittra Poorahong https://spast.org/techrep/article/view/515 Thu, 16 Sep 2021 00:00:00 +0000 Influence of Industrial By-Product Materials on Bituminous Concrete Mixes https://spast.org/techrep/article/view/2668 <p>In this research work, the purpose of the laboratory studies is to use industrial by-products<br>Copper slag and Foundry sand as Mineral Fillers (MF) and Fine Aggregate (FA) in<br>bituminous concrete mixtures in place of natural mineral fillers and fine aggregate materials<br>will help create sustainable roadways. The aggregate gradation corresponding to the<br>bituminous Concrete mid-limit grading-2 mixture was chosen as per section 500 Table<br>No.500-18 of MORT&amp;H 4th revision specifications and the VG-30 bitumen is utilized as the<br>binder for the preparation of bituminous concrete grade-2 mixtures. The research study is<br>done in two stages. In the first phase, the research study of the bituminous concrete grading-2<br>mixture replacing conventional mineral fillers with 0, 25, 50, 75 and 100 percent of industrial<br>by-products using Copper slag mineral filler(CSMF) and foundry sand mineral filler (FSMF)<br>was done and similarly in the second phase, studied on the bituminous concrete mixtures<br>replacing conventional mineral fillers and fine aggregate with 0, 25, 50, 75 and 100 percent<br>of industrial by-products utilizing copper slag fine aggregate mineral filler (CSFAMF) and<br>foundry sand fine aggregate mineral filler (FSFAMF). The morphology and elemental<br>composition study carried at Jyothi Institute of Technology (Centre for Incubation,<br>Innovation, Research and Consultancy (CIIRC), Bangalore) on CS-FA (Copper slag fine<br>aggregate), FS-FA (Foundry sand fine aggregate), CS-MF (Copper slag mineral fillers) and<br>FS-MF (Foundry sand mineral fillers) are analyzed through Scanning electron microscope<br>(SEM) and Energy dispersive X-ray analyzer (EDXA) techniques respectively. Marshall<br>mixture design method is used to design the bituminous concrete mid limit grading-2 mixtures (BC2) with replacement 0, 25, 50, 75 and 100 percentages of IBP-MF (Industrial<br>by-products as mineral fillers) and IBP-FAMF (Industrial by-products as fine aggregate and<br>mineral fillers) respectively. The Static Split Tensile strength of the bituminous concrete<br>grading-2 mixtures replacing conventional materials with 0, 25, 50, 75 and 100 percent of<br>industrial by-products using CSMF, FSMF, CSFAMF, and FSFAMF are evaluated in<br>accordance with AASHTO T283. The loss of adhesion of the aggregates with binder is<br>studied by measuring the split tensile strength ratio (STSR) of bituminous concrete grading-2<br>mixtures (BC2). Split tensile strength (STS) of the mixture is determined before and after<br>conditioning of Marshall cylindrical specimens. The Marshall Stability of the bituminous<br>concrete mixtures increased with increasing CSMF, FSMF and CSFAMF content. While<br>increase of FSFAMF content in the bituminous concrete mixtures has decreased the Marshall<br>Stability value compare to CSMF, FSMF, CSFAMF, and conventional material added<br>bituminous concrete mixtures. From ITS test results, split tensile strength of the mixtures is<br>increased with copper slag (CS-FAMF and CS-MF) and foundry sand (FS-MF) contents.<br>However, the poor interlocking property of foundry sand fine aggregate particles (FS-FAMF)<br>reduces its strength. The conditioned split tensile strength value of the CS-FAMF bituminous<br>concrete mixture was found to be the highest of all mixers. Water resistance testing of<br>bituminous concrete mixtures measured at 25, 45 and 65 degrees Celsius, the split tensile<br>strength ratio of all mixtures meets the prerequisite minimum requirement. Thus, the research<br>study has indicated that the utilization of VG30 and Bituminous concrete grading-2 mixtures<br>permits use of copper slag (CSMF and CSFAMF) and Foundry sand (FSMF) materials in the<br>mixture. Furthermore, the application of copper slag and foundry sand would minimise the<br>quantity of traditional aggregate required in highway construction, benefiting the<br>environment at the same time.&nbsp;</p> Chavan Ravishankar, MS Nagakumar Copyright (c) 2021 Chavan Ravishankar, MS Nagakumar https://spast.org/techrep/article/view/2668 Thu, 21 Oct 2021 00:00:00 +0000 Miscibility study of amorphous Poly(vinyl chloride) and semicrystalline Poly (vinylidenefuoride-co-Hexafluoropropylene) blends https://spast.org/techrep/article/view/592 <p>&nbsp;It has been recognized that the useful physical properties of polymers depend not only on the chemical structure but also on their supermolecular organization [1-2]. Polymers are characterized by a large number of intermediate stages of ordered arrangement of chains i.e. the existence of various levels of supermolecular organization which intervene between the crystalline and completely amorphous phases, the kind of observed morphology depends on the chemistry of the chain, these molecular architectures can result in new morphologies in dense state of these molecules like phase or microphase separated structures, especially in case of polymeric blends. Studies on polymeric blends, is therefore, important from the point of view of understanding morphology- property relationship or properties in relation to the crystalline and amorphous content of the polymer. <br>The amorphous polymer in general, brittle in nature and require blending more frequently. Blending of semicrystalline polymer into an amorphous polymer can improve toughening, solvent and chemical resistance. Poly (vinyl chloride) (PVC) is the example of homogeneous linear polar polymers, which are optically transparent, chemical resistance, high Tg, low dielectric loss and high <br>break down strength but on the other hand, cannot be used in specific end applications due to brittle nature of fracture [3]. This drawback can be eliminated by incorporation Poly (vinylidene fuoride-co-hexafluoropropylene) (PVDF-HFP) which is soft in nature and significant dielectric constant with low Tg. PVDF is semicrystalline polymer which has drawn both scientific and technological attention because of the useful piezo- and pyroelectric properties. It is also one of the rare polymer that exhibits diverse crystalline forms, having atleast five phases known as α, β, γ, δ and ε [4]. <br>The commercial Poly (vinyl chloride) PVC (powder) and Poly (vinylidene fuoride-co-hexafluoropropylene) PVDF-HFP (pallets) used in the present study were obtained from Sigma-Aldrich Chemicals Private Limited (India). Polymers and the chemicals were used as supplied without any further purification. The samples for the present investigation were prepared by the solution cast <br>technique [5]. The solution of particular concentration was prepared by dissolving the two polymers PVC and PVDF HFP in different weight ratios in their common solvent N, N, Dimethyl formamide (DMF) at various temperatures i.e. 50, 60, 90 and 100°C. Blend samples of size 6 cm2, with thickness approximately 20±5 μm and of wt% compositions PVC: PVDF:: 100:0; to 0:100, were prepared. The prepared films were characterized by FTIR, XRD and DSC techniques for structural, morphological and miscibility studies, respectively. FTIR and XRD analysis confirms the molecular interaction between the two polymers and also the dominating presence of α and β-phase PVDF-HFP depends on film preparing conditions [6]. Studies also suggested that the crystallinity occurs in blend samples with increase of PVDF-HFP wt%. Experimental and theoretical DSC analysis exhibited single Tg and position of Tg decreases with increasing wt% of PVDF-HFP in blend sample upto certain limit. Different characterization in present investigation indicates that low wt % of PVDF-HFP act as a plasticizer in blends, prepared blends are miscible/ or compatible in various composition range and strongly depends on dissolving/ and evaporating temperature conditions. <br><br></p> Shivangi Shukla Copyright (c) 2021 Shivangi Shukla https://spast.org/techrep/article/view/592 Sun, 19 Sep 2021 00:00:00 +0000 Formation of Air Stable Fe88Co12 Alloy Nanoparticle Prepared by High Energy Ball Milling https://spast.org/techrep/article/view/1650 <p>The mechanical alloying procedure used to manufacture nanostructured materials &nbsp;has been a major focus in recent years [1]. Fe<sub>88</sub>Co<sub>12</sub> alloys are useful in a variety of fields, including magnetic storage and composite permanent magnets. Because of their unique magnetic properties, such as high permeability and higher saturation magnetization per volume than any other material, Fe<sub>88</sub>Co<sub>12 </sub>alloys are an important soft magnetic material [2]. However, its nanostructures such as grain size, internal strain and crystal structure has a complicated effect on the magnetic parameters of nanostructured materials. For a considerable improvement in magnetic characteristics experiments on synthesis of nanostructured materials are therefore necessary with controlled nanostructure [3]. Different methods were utilised to make nanostructured alloy powders including rapid solidification, inert gas condensation, electrodeposition, and mechanical alloying. In these techniques, Mechanical ball milling remains the most popular and efficient technology for its manufacturing, especially given the vast industrial scale of the applications. Mechanical alloy (MA) is an advantageous approach for easy operation, producing high volumes of nanostructured powders in short periods [4].</p> <p>Nanostructured Fe<sub>88</sub>Co<sub>12</sub> powders were prepared by high-energy ball milling. The schematic diagram of the Ball Milling technique used for preparing (Fe<sub>88</sub>Co<sub>12</sub>) nanoparticles is shown in Fig. 1. The ball milling was undertaken using tungsten carbide balls with a diameter of 20mm, at 300 r.p.m., and with a ball-to-powder ratio of 10:1. It is vital to emphasise that the mechanosynthesis has been performed in the air and the handling of the samples has always been done outdoors. Data sheet of both the materials used for the synthesis of Fe<sub>88</sub>Co<sub>11</sub> are given in Table 1, with their chemical formula, company from which they were purchased, grade and purity. Thermal studies such as thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were performed on the synthesized samples, in order to know the thermal stability and the phase formation temperature. Phase identification of prepared powders was done by X-ray diffraction (XRD) analysis. Microstructural characteristics such as morphology, particle size and crystal structure were analyzed by scanning electron microscope (SEM) and transmission electron micro- scope (TEM). Study on the chemical composition and the oxidative states of the synthesized samples were analysed using x-ray photoelectron spectroscopy (XPS). The magnetic property of the powders was estimated using a vibrating sample magnetometer (VSM) with an applied magnetic field at room temperature.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; All published results on the subject until now use ball milling in the argon environment and glove boxes in many cases for handling the materials [5,6]. The impact of performing FeCo alloy synthesis in air rather than the conventional argon atmosphere is investigated with the goal of developing cost-effective processes. The usage of argon atmospheres, desiccators, and glove boxes can all be eliminated from the process without harming the magnetic characteristics, according to the findings. We also discuss the effect on magnetic characteristics of the microstructure like the crystal structure and the grain size of Fe-Co alloys.</p> <p><strong>Table 1.</strong> Data sheet for the precursor materials used and their respective chemical formula, company, grade and purity percentage.</p> <table> <tbody> <tr> <td width="150"> <p><strong>Material</strong></p> </td> <td width="150"> <p><strong>Chemical formula</strong></p> </td> <td width="150"> <p><strong>Supplier &amp; Grade</strong></p> </td> <td width="150"> <p><strong>Purity</strong></p> </td> </tr> <tr> <td width="150"> <p><strong>Iron</strong></p> <p><strong>&nbsp;</strong></p> <p><strong>Cobalt</strong></p> </td> <td width="150"> <p>Fe</p> <p>&nbsp;</p> <p>Co</p> </td> <td width="150"> <p>SRL</p> <p>&nbsp;</p> <p>HPLC</p> </td> <td width="150"> <p>99.5%</p> <p>&nbsp;</p> <p>99.5%</p> </td> </tr> </tbody> </table> Saraswathi Palani, Madeswaran Saminathan Copyright (c) 2021 Saraswathi Palani, Madeswaran Saminathan https://spast.org/techrep/article/view/1650 Fri, 08 Oct 2021 00:00:00 +0000 A Ag ion implantation induced phase transformation in Cupric Oxide thin films https://spast.org/techrep/article/view/723 <p>The present study focuses on the effect of 30 keV Ag ion implantations on the Cupric Oxide thin films deposited on Silicon by the thermal evaporation technique. These thin films were implanted with varying Ag ion fluences 1E14, 5E14, 1E15, 5E15 and 1E16 ions/cm2 at low energy ion beam facility of Inter University Accelerator Centre, New Delhi and characterized by X-ray diffraction (XRD), Raman Spectroscopy, Atomic force microscopy and Fourier transform infrared techniques. The XRD reveals the formation of pure CuO thin films in as-deposited films, and also in the Ag ion implanted films with the ion fluences of 1E15 and 5E15 ions/cm2.&nbsp; With higher ion fluence of 1E16 ions/cm2, the XRD pattern shows the presence of Cu­2O phase.[1] FTIR results show the presence of functional groups both in pure and implanted CuO thin films. Results from the AFM reveal that the roughness and grain size increase with the ion fluences.[2] Raman results confirm the phase change consistent with XRD results. These results show that Ag ion implantation induces the formation Cu2O phase.</p> Rekha Yadav Rekha Yadav Copyright (c) 2021 Rekha Yadav Rekha Yadav https://spast.org/techrep/article/view/723 Wed, 15 Sep 2021 00:00:00 +0000 Synthesis, characterization and photocatalytic activities of Co3O4 - MnO2 - ZnO ternary nanoparticles https://spast.org/techrep/article/view/839 <p>Co<sub>3</sub>O<sub>4</sub> - MnO<sub>2</sub> - ZnO NPs were synthesized by making use of the equimolar solutions of cobalt chloride, manganese(II) sulfate and zinc sulfate in aqueous sodium hydroxide and refluxed at elevated temperature. The synthesized mixed nano oxides were characterized by FT-IR, XRD, UV - Vis DRS, TEM, SAED, SEM, EDAX, AFM, TG/DTG and DSC.&nbsp; The FTIR spectra confirm the presence of M-O bonds (M = Co, Mn, Zn). The size of the Co<sub>3</sub>O<sub>4</sub> - MnO<sub>2</sub> - ZnO NPs are found to be 10.13 - 25.65nm through XRD studies. The XRD patterns also expose that the particle size is significantly increased with increasing concentration of the precursors. From UV-Vis diffuse reflectance spectra (DRS), band gap energies of the (0.1 – 0.5M) Co<sub>3</sub>O<sub>4</sub> - MnO<sub>2</sub> - ZnO NPs are found to be in the range of 2.23 – 2.42Ev [1]. The TEM, SEM and AFM micrographs of 0.1M Co<sub>3</sub>O<sub>4</sub> - MnO<sub>2</sub> - ZnO NPs show roughly spherical shape with size ranging from 10 - 30nm. SAED pattern confirms the crystalline nature of these nanoparticles. EDAX analysis confirms the presence of Co, Mn, Zn and O. From TG-DTG and DSC studies, it is found that Co<sub>3</sub>O<sub>4 </sub>- ZnO - ZrO<sub>2 </sub>NPs are thermally stable [2]. The photocatalytic activity of Co<sub>3</sub>O<sub>4</sub> - MnO<sub>2</sub> - ZnO NPs was determined for degradation of methylene blue (MB) under sunlight. Among the samples, 0.1M Co<sub>3</sub>O<sub>4</sub> - MnO<sub>2</sub> - ZnO NPs exhibits the best performance (91.98%) for the degradation of MB in 90 min of irradiation time under sunlight [3,4]. The factors influencing the photocatalytic activity are pH of dye solution, photocatalyst particle size, photocatalyst dosage and dye concentration.</p> Alwin David S Copyright (c) 2021 Alwin David S https://spast.org/techrep/article/view/839 Sat, 18 Sep 2021 00:00:00 +0000 A review on impact resistance of fiber reinforced - self compacting concrete https://spast.org/techrep/article/view/2540 <p>This paper gives the review on the impact resistance of fibre-reinforced self-compacting concrete (FR-SCC) with various fibers (i.e., steel, glass, polypropylene, natural and hybrid fibers). Several kinds of test methods on impact test which are currently available are addressed through extensive literature study. In this study, responses of materials obtained through impact tests such as drop weight impact test, split Hopkinson pressure bar test, projectile impact test, drop weight hammer machine and fiber pull out test are classified and briefly addressed here. The geometric of fibers and volume fraction of fibers influence the fresh concrete properties and play an important role when they are exposed to impact and high-velocity loading. After summarizing the impact properties of FR-SCC the fiber that gives better results against the impact resistance is discussed here. The effect of supplementary cementitious materials (SCMs) on the impact resistance of FR-SCC is voiced here. To enhance the impact resistance, some combination of SCM and fiber types are suggested.&nbsp;&nbsp;</p> Kesavamoorthi R Copyright (c) 2021 Kesavamoorthi R https://spast.org/techrep/article/view/2540 Sun, 17 Oct 2021 00:00:00 +0000 Biomarkers of Pulpal Regeneration: Overview on Immunohistochemistry analysis https://spast.org/techrep/article/view/2684 <p>Management of inflammation is crucial when considering success for therapy aiming to preserve, maintain, or restore dental pulp in a healthy state namely “vital pulp therapies” (VPT). The removal of the pulp has a number of drawbacks. Teeth may become fragile, susceptible to fractures, and infected. The removal of the pulp also stops the natural healing and alarm signals from taking place. As a result, the goal of such therapies is to reduce tissue damage after an injury while also controlling the inflammatory immune response in order to promote a return to homeostasis and pulp healing. To enhance pulp healing, repair, or regeneration, various strategies have been, are being, and will be proposed(1). Stem cells must first develop into odontoblasts before they may produce new dentin. Human exfoliated deciduous teeth stem cells were able to develop into odontoblast-like cells that lined against the existing dentin surface as researched&nbsp;in vivo investigations. These findings imply that the presence of dentin in the canal space is sufficient to direct stem cells into odontoblast-like cells. This capacity seems to be unaffected by dentin chemical treatment(2).</p> <p>The most prevalent sources of endodontic diagnosis are the patient's medical history, radiography, and vitality tests. Radiographs help the doctor diagnose the lesion during intra- or inter-operative operations, as well as during post-operative assessment after root canal therapy. The radiographic technique can only show the position and size of a periapical lesion, not the pathology's specific type(3). The importance of submitting the material for histological investigation stems from the truth that interpreting the cystic formation properly based on the appearances of the radiograph is difficult. It gives a fantastic chance to learn everything there is to know about the pathology and microbiology of the lesion(4). The introduction of monoclonal and polyclonal antibodies that recognise epitopes in a range of extracellular matrix components of the dentition is a useful tool for studying the structure and biology of dental tissues in health and illness. Immunolocalization of whole compound structures as well as specific regions of molecules has the potential to provide details on tooth development, ageing effects, variations in tooth structure throughout the initiation and progression of the caries process, as well as the tooth's reaction to restorative treatment.</p> <p>For more than 50 years, scientists have known that antibodies may be employed in cytochemistry if they are properly labelled. Immunocytochemistry is the process of identifying a tissue component in situ using unique antibody-antigen interactions in which the antibody has been specifically&nbsp;labelled. In development, health, and disease, immunohistochemistry allows for the identification and localization of well-known cellular structures and extracellular matrix components, as well as information on the temporo-spatial distribution of newly described proteins and carbohydrates(5).</p> <p>IHC is a technique for determining the tissue distribution of an antigen of interest in health and illness using monoclonal and polyclonal antibodies. Because particular tumour antigens are expressed de novo or up-regulated in certain malignancies, it is frequently utilised for cancer detection. In pathology, IHC is particularly significant in the subspecialties of oncologic pathology, neuropathology, and hematopathology. Although there are few research on the diagnostic usefulness of IHC in surgical pathology, some writers have done so(6). Immunohistochemistry was used to examine the reparative process of mechanically exposed rat molar pulps capped with MTA. The location of cells expressing nestin (an intermediate filament expressed in differentiated odontoblasts) was investigated using a cell proliferation test with 5-bromo-2-deoxyuridine (BrdU) labelling. Osteopontin (a noncollagenous protein involved in matrix mineralization, cell-matrix interaction, and cytodifferentiation) immunolocalization was also performed(7).</p> <p>Immunohistochemistry can thus be utilized in Endodontics as a diagnostic aid as well as a possible marker for odontogenic tissues. Periapical lesions have an ambiguous radiographic diagnosis. Although histopathologic analysis of periapical lesions provides the real nature of the lesions, immunohistochemistry markers can be used to further refine the nature of specific lesions.</p> Serene Joy Copyright (c) 2021 Serene Joy https://spast.org/techrep/article/view/2684 Thu, 21 Oct 2021 00:00:00 +0000 First principles study of pressure-induced structural phase transitions in BaO https://spast.org/techrep/article/view/2627 <p class="western" align="justify"><span style="color: #222222;"><span style="font-family: Arial, serif;">Barium oxide (BaO) is one of the most important binary alkaline-earth metal oxide being a possible component of Earth’s lower mantle </span></span><span style="color: #222222;"><span style="font-family: Arial, serif;">[1]</span></span><span style="color: #222222;"><span style="font-family: Arial, serif;">. Exploring the phase diagram at high pressure and temperature of alkaline-earth metal oxides provide insights on compositions of lower mantle. In the present work, we have investigated pressure-induced structural phase transitions in BaO using first principles calculations within the frame work of density functional theory. We found series of structural phase transitions B1 </span></span><span style="color: #222222;"><span style="font-family: Wingdings, serif;">--</span></span><span style="color: #222222;"><span style="font-family: Wingdings, serif;">&gt;</span></span><span style="color: #222222;"><span style="font-family: Arial, serif;"> B8 </span></span><span style="color: #222222;"><span style="font-family: Wingdings, serif;">--</span></span><span style="color: #222222;"><span style="font-family: Wingdings, serif;">&gt;</span></span><span style="color: #222222;"><span style="font-family: Arial, serif;"> distorted B2 (D-B2) </span></span><span style="color: #222222;"><span style="font-family: Wingdings, serif;">--</span></span><span style="color: #222222;"><span style="font-family: Wingdings, serif;">&gt;</span></span><span style="color: #222222;"><span style="font-family: Arial, serif;"> B2 below 100 GPa and the transition sequence is in excellent agreement with high pressure X-ray diffraction measurements </span></span><span style="color: #222222;"><span style="font-family: Arial, serif;">[2-3]</span></span><span style="color: #222222;"><span style="font-family: Arial, serif;"> and with previous theoretical calculations </span></span><span style="color: #222222;"><span style="font-family: Arial, serif;">[4-5]</span></span><span style="color: #222222;"><span style="font-family: Arial, serif;">. B33 phase is found to be meta-stable for BaO. We have calculated electronic structure with Tran-Blaha modified Becke-Johnson potential (TB-mBJ) potential and the obtained band gaps are improved over standard PBE-GGA functional. BaO is found to be a direct band gap insulator at ambient pressure and no metallization is observed until 100 GPa. </span></span></p> Kunduru Lavanya, N Yedukondalu, Suresh Sripada, Sainath Manikonda, Sainath Manikonda Copyright (c) 2021 Kunduru Lavanya, N Yedukondalu, Suresh Sripada, Sainath Manikonda, Sainath Manikonda https://spast.org/techrep/article/view/2627 Sun, 17 Oct 2021 00:00:00 +0000 Influence of Silicate Content on Properties of Paste Phase of Alkali Activated Composites https://spast.org/techrep/article/view/1731 <p>Ordinary Portland cement (OPC) is the most important binding material used in the construction industry for various infrastructure applications.OPC is suitably identified for its performance since years by its well known chemistry. Every year construction industry yields around 1.6 billion of OPC, proportionally; it’s far- famed to own several drawbacks namely, greenhouse gas emission, consumption of huge resources and requirement of enormous energy for its production [1-3].Further, it can be noticed that OPC experiences deterioration process, when exposed to the elevated temperature, due to the alterations in physical and chemical properties. [4,5].</p> <p>Keeping in view of the hazardous effects during the production of OPC, it has become truly essential to find alternative binding materials that can effectively replace OPC. One such attempt led to the invention of Alkali Activated Composites (AAC), which involves either full replacement or partial replacement of OPC by Alkali activated materials. AAC are found to be inorganic alternative binder for OPC due to their better properties at high temperature with eco friendly nature.</p> <p>Various research works have been carried out on alkali activated materials by utilizing different base materials namely Fly Ash, Ground Granular Blast Furnace Slag (GGBS), Alumina Refinery Residue (ARR), Rice Husk Ash and also by combining of these materials. ARR and GGBS are the two major alternative source materials used in the present study</p> <p>ARR is the waste generated during extraction of aluminum from bauxite ore through multiple Bayer's process. Nearly 4 million tons of red mud is produced every year across the world. Disposal of red mud directly into land or pond can contaminate ground water; pollute soil due to its high alkaline property. GGBS is by-product in iron and steel making. Ground-granulated blast furnace slag is highly cementitious and high in CSH (calcium silicate hydrates) which is a strength enhancing compound which improves the properties of Composites. In most of the research sodium silicate, sodium hydroxide is used as an alkaline activation agent. Present experimental study involves usage of plagioclase based activator such as sodium feldspar as alkaline activator along with sodium hydroxide in order to initiate the polymerization reaction to produce the resultant Alkali activated composites.</p> <p>The effect of silica content of the alkaline activator solution on the mechanical, physical and micro structural properties of paste phase of alkali activated composites has been studied. The ratios of SiO<sub>2</sub>/Na<sub>2</sub>O were varied from 0.2 to 1.2 and further the test specimens were subjected to water curing at room temperature condition. The compressive strength was determined for the curing period of 3, 7, 14 and 28 days. It has been observed that the compressive strength of the test specimens increases with increase in ratio of SiO<sub>2</sub>/Na<sub>2</sub>O to 0.8.The optimum compressive strength was found to be 43.54MPa for 28 day curing period. It could be noticed that the ratio of SiO<sub>2</sub>/Na<sub>2</sub>O (silicate ratio) has a major influence on water absorption and porosity. The microstructure and mineralogical characterization of paste phase of AAC were studied using SEM/EDAX and XRD. Whereas, porosity, pore size distribution and total volume of pores were studied by using MIP (Mercury intrusion porosimetry)</p> Nagashree B, Mourougane R Copyright (c) 2021 Nagashree B, Mourougane R https://spast.org/techrep/article/view/1731 Fri, 08 Oct 2021 00:00:00 +0000 Evolution of Bi2Te3 nanoflowers through imperfect orient attachment growth https://spast.org/techrep/article/view/763 <p>Thermoelectricity offers a green technology through interconversion of heat and electrical energies by employing thermoelectric generators and coolers [1]. Thermoelectric generators provide an attractive source of non-conventional energy due to its multi advantages like long life, less maintenance and silent operation. They can be used for improving the overall efficiency of system by waste heat recovery. The thermoelectric conversion efficiency of a thermoelectric material can be evaluated in terms of its dimensionless figure of merit, , where S, σ and κ stands for the Seebeck coefficient, electrical conductivity and thermal conductivity of the material [2]. Extensive studies were focussed on improving the conversion efficiency of thermoelectric materials and to boost its value above unity.</p> <p>Nano structuring of a material is found to be effective in attaining simultaneous improvement in S and reduction in thermal conductivity, leading to improved ZT [3]. A factorial improvement in S can be achieved through enhanced density of states near fermi level. The reduced dimensions of the material will offer more grain boundaries to scatter phonon effectively compared to charge carriers, resulting in suppressed thermal conductivity.</p> <p>Bi<sub>2</sub>Te<sub>3 </sub>is a well-established material suitable for small scale waste heat recovery and thermoelectric&nbsp; cooling [4]. The size, shape and properties of Bi<sub>2</sub>Te<sub>3 </sub>nanostructures can be tailored to meet the challenges involved in improving ZT. Extensive studies were conducted in the field of preparation of Bi<sub>2</sub>Te<sub>3 </sub>nanostructures with tuned morphology [5,6]. Recently special attention was focussed towards growing anisotropic crystals including nanoflowers, nanoribbons, nanotubes and other hierarchial structures [7-9]. A precise control over the size and shape of nanostructures made the hydrothermal procedures a promising one. The well-understood Ostwald ripening process cannot explain all phenomena behind the morphological evolution of nanostructures [10].</p> <p>In this work, Bi<sub>2</sub>Te<sub>3</sub> nanoflowers were successfully synthesized through hydrothermal method. The effect of reaction time on crystal growth and the morphological evolution of these nanoflowers were studied in detail. The obtained nanopowders were characterized by employing XRD, FESEM, EDAX, HRTEM and Raman studies. The XRD results shows that rhombohedral Bi<sub>2</sub>Te<sub>3</sub> is obtained, without any impurities, at a reaction time of 8, 24 and 36 hours. But along with Bi<sub>2</sub>Te<sub>3</sub>, elemental Te is obtained at a reaction time of 4 hours. A growth mechanism for the evolution of nanoflowers from primary nanoplates is proposed, based on the experimental results. The HRTEM images shows that an imperfect orient attachment of primary nano plates &nbsp;leads to the twisting and bending of nanoplates, resulting in well-formed nanoflowers.</p> Shyni P., Prof. Copyright (c) 2021 Shyni P., Prof. https://spast.org/techrep/article/view/763 Wed, 15 Sep 2021 00:00:00 +0000 Flexible, Stretchable strain sensor on PANI-MWCNT/PU polymer nanocomposite for Biomedical Applications https://spast.org/techrep/article/view/1827 <p>With the increase in the number of several movement-based diseases like Parkinson’s disease, Ataxia etc, there has been an increase in the biomechanical applications in the field to wearable devices which can help the patients to mobilize their movements in a better manner. The demand for these biomechanical sensors is very high these days hence there is a need to adopt a stretch sensor that is biocompatible, has good stability, has managerial temperature and pressure-bearing conditions. The use of Intrinsically conducting polymers (ICPs) has played a significant role in various technological advancements like rechargeable batteries, EMI shielding, Gas sensors, and optical devices [1]. The growth of these Intrinsically conducting polymers has led us to develop some applications in the field of medical sciences and biomedical advancements. Several MedTech industries are currently in need of strategies for developing stretch sensors that are biocompatible which can be helpful to analyze the gait pattern of patients and analyze the mobility, have few adverse effects, and are stable [2]. The polyaniline-based nanocomposite can be used in several manners in the development and implementation of stretch sensors which can be further use in the applications of wearable devices [3-4]. The preparation of PANI-MWCNT/PU based Nanocomposite is the most important and vital task in the formation of the stretch sensor. Although, the synthetic methods to produce polyaniline are quite simple, the mechanism of polymerization is probably complex. Oxidative Polymerization takes place. Here the Carbon nanotubes play a vital role in enabling as a reinforcing agent to increase the strength and stability of the polymer by having a strong bond reinforced in them. CNTS are promising effect on tunnelling to bridge gap particle to particle , this makes increase in overall conductivity of nanocomposite.</p> <p><img src="https://spast.org/public/site/images/niranjandb/mceclip1.png"></p> <p>Fig.1: (a) shows the synthesized PANI powder and (b) FTIR peaks of PANI powder &nbsp;</p> <p>Preparation of PANI powder includes following process [5], Aniline was mixed with 0.1M HCl (20ml) with the help of a magnetic stirrer at 700 rpm. The mixing took place for around 30 minutes on a magnetic stirrer. In another beaker Ammonium Persulphate (APS) was added and 10 ml of de-mineralized water was put into it. It was mixed thoroughly for 20 minutes, and a greyish kind of solution was obtained. The beaker containing the solution of Aniline with HCl was put on an ice bath to maintain 10˚C. After it attained a temperature of 10˚C, the solution of Ammonium persulphate with de-mineralized water was put inside a dropper. During this time the solution which was inside the dropper was put inside the solution of Aniline and HCl drop by drop. This process continued for 1hr to put the whole greyish solution inside it. The mixing continued the stirrer for about 3 hours with the maintained temperature of 10˚C until a greenish-black colour is obtained. After nearly 3-4 hours it was showing greenish-black colour which was showing conductivity. The conductivity was measured with the help of a multimeter, and the results were analyzed for further study.</p> <p><img src="https://spast.org/public/site/images/niranjandb/mceclip2.png"></p> <p>Fig.2: (a) shows the PANI-MWCNT/PU nanocomposite and (b) Fabricated Stretch sensor &nbsp;&nbsp;</p> <p>PANI and MWCNTs are stabilized in DMF solvent. PU added to PANI-MWCNT solution stir for 24h for uniform distribution of particles in PU. Then it dried in electric oven under 50<sup>o</sup>C for 6 h to make nanocomposite as shown in Fig 2 (a). Obtained thin film fabricated to required shape then added copper strip at both ends with aid of silver paste, again it insulated with PU, As shown in fig.2 (b). To examine the electrical resistance of PANI-MWCNT/PU nanocomposite FLUKE 17B+ Digital multimeter used. The macroscopic electrical resistance of composite increases as strech percentage increases.</p> <p>The PANI-MWCNT/PU based nanocomposite was created by combining multiple distinct compounds and treating them with various solvents to create a perfect combination, and then applying the same to matrix-based materials such as polyurethane and others to give the compound a matrix-like structure. The change resistance indicates that it is most suited for use in a stretch sensor, which can then be further tuned utilizing microcontrollers to meet the needs of the individual.</p> <p>To summarize the work, PANI-MWCNT/PU based nanocomposite is suitable for development of stretch sensors that may be used to help monitor patients gait signals suffering from movement-related disorders. These stretch sensors aid in the early detection and continuous monitoring of movement disorders through gait analysis, allowing us to determine the appropriate treatment.</p> <p>&nbsp;</p> Niranjan D B, Dr Pramod K, Shibashish S Copyright (c) 2021 Niranjan D B, Dr Pramod K, Shibashish S https://spast.org/techrep/article/view/1827 Sat, 09 Oct 2021 00:00:00 +0000 Utilization of Agricultural Waste materials in Building Industry – An overview https://spast.org/techrep/article/view/305 <p>Agricultural wastes have become an increasing concern in recent years due to the increasing population. A large amount of agricultural wastes is produced while harvesting, and processing products. This is degrading surrounding ecosystems. In many developing countries large quantities of these wastes are generated and not properly managed because of their potential risks. Agricultural solid wastes are dumped or burned in public locations indiscriminately in many parts of the world, resulting in air pollution, soil contamination, hazardous gas, smoke. The residue may be channelled into a water source, contaminating the water and aquatic ecosystem.</p> <p>&nbsp;Agricultural waste materials are crushed and made into fine and coarse aggregates or burnt into ash, which are used in concrete production. The present paper explores the various structural components prepared by using Agricultural Waste materials, such as bio-bricks, Natural fibre components, Lightweight concrete, Green concrete, concrete roofing, tile components. Agricultural solid waste is a lightweight aggregate used in the production of masonry blocks [1]. &nbsp;The utilization of rice husk, groundnut shell, maize stalk in the preparation of bio-composite materials. This will be strengthening the thermal insulation, sound absorption, water stability, fire resistance, and mechanical characteristics of green concrete [2]. Bamboo, Banana, coir, Cotton, Jute, and Sisal plant fibrous materials are used for producing fire-resisting fibreboards, roofing sheets, flooring tiles, masonry blocks, door shutters. [3-6]</p> <p>Oil Palm Shell (OPS) is a solid waste originating from the palm oil industry and is available in large quantities in the tropical regions and has been found that OPS can be used as coarse aggregate for the manufacture of structural lightweight concrete [7].</p> <p>Coconut shell (CS) is an agricultural waste and is available in throughout tropical countries worldwide. In many countries, coconut shell is subjected to open burning which contributes significantly to CO<sub>2</sub> and methane emissions, besides that, coconut shell is development of new composite material (fine or coarse) in concrete mix design because of their high strength and modulus properties. [8]</p> <p>&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;</p> <p>Fig.1. A. Coconut Shell Aggregates&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; B. Coconut husk bricks</p> <p>Different types of agricultural waste materials such as periwinkle shell, date seed, corn cob, pistachio shell, giant reed fibres and giant reed ash have been used as partial or full replacement for natural aggregate (fine or coarse) concrete and their properties have compared with conventional concrete. The use of agricultural waste in sustainable construction materials compensates for the deficiency of natural resources and solves the waste disposal problem</p> <p>This review is an attempt to collect global data with references for agricultural waste application also increasing the economic value of agricultural waste by converting it into valuable construction products. The application of agro-waste for sustainable construction materials provides a solution which offers reduction in natural resource use as well as energy.</p> Anitha K Copyright (c) 2021 Anitha K https://spast.org/techrep/article/view/305 Fri, 17 Sep 2021 00:00:00 +0000 Electron Transport across Phycobiliproteins Films and its’ Optoelectronic Properties https://spast.org/techrep/article/view/1352 <p>Biomolecules, especially proteins are promising candidates for nano-electronic circuit development due to their binding selectivity to conducting substrates and persistence of chemo-mechanical, electro-mechanical, optomechanical, and optoelectronic processes at dry, solid-state film condition. Electron transfer (ET) reactions are principal to an extensive range of biological processes, notably for energy conservation such as the respiratory and photosynthetic chains where proteins help electron to shuttle from one electron mediator to another mediator by electrochemical redox processes.[1] ET through proteins, a fundamental element of many biochemical reactions, is studied intensively in aqueous solutions. &nbsp;Knowledge of electrical transport properties across biofilms is beneficial to implement in preparing biocompatible electronic devices such as protein-based Field Effect Transistors (FET), Biosensors. There have been attempts to explore the electronic conductance of various single proteins or its’ monolayer in both wet (electrochemical STM) and solid-state configurations (self-assembled monolayer).[2] The understanding of single-molecule electron dynamics and fabrication of single-layer molecule device will enable a robust single-molecule sensor that is precise to the sensed, analytic and have boosted sensitivity of current conductance-based biosensors.[3] Exploration of transport properties across proteins, which demonstrate its structural modification with external stimuli, such as light, electric field, chemical environments, establishes that electronic transport across biomolecule can be modulated with external stimuli. Here, we report electronic transport modulation across Phycobiliproteins protein films with light as external stimuli. Phycobiliproteins (PBPs) are the main component of light-harvesting complexes in cyanobacteria and red algae where they organize supramolecular antenna complexes called phycobilisomes.[4] These complexes are responsible for harvesting a high-energy spectrum band of visible light. PBPs efficiently capture and transmit light energy in deep-water areas, in particular, the blue-green light that can penetrate deep water. The low light adoption (light intensity of 30–50 µmol photons m<sup>-2</sup>s<sup>-1</sup>) properties of PBPs make them an ideal candidate for sensitive optoelectronic detectors at the visible spectrum and low light intensity level.</p> <p>Aiming to develop low light intensity, sensitive detector here we have explored the optoelectronic transport across photoactive Phycobiliprotein, by integrating the protein films between two metal electrodes. To understand the ET in phycobiliproteins, we have explored photochemical properties and electrical transport efficiency across phycobiliproteins (PBPs) films by depositing it on clean FTO substrate as bottom electrode and liquid metal eutectic-GaIn as top electrode. We observed that PBPs were less stable under white light exposure when it was present in buffer solution, whereas PBPs maintain their photochemical properties in the dry solid-state films, even with 48 hours white light exposure. To obtain better electrical conductance, we have optimized film thickness by varying protein concentration in solution. We report the enhancement in the electrical conductivity across the PBPs films when illuminated with low-intensity white light. The conductance enhancement is attributed to the isomerization of chromophores present in the protein and alteration of the electrostatic environment due to the isomerization process. The electron transport through the PBP films is dispersive and the activation energy could be obtained from a temperature-dependent transport study, currently ongoing at our laboratory. Our observations depict that the photoconduction property of PBPs film will be suitable for low-intensity light detectors, and optogenetics applications.&nbsp;</p> Ashwini Nawade Copyright (c) 2021 Ashwini Nawade https://spast.org/techrep/article/view/1352 Wed, 06 Oct 2021 00:00:00 +0000 Optimization of anode electrode resistance using synthesised graphene oxide for DSSC applications https://spast.org/techrep/article/view/976 <p>The graphene oxide is synthesized by modified hummer’s method.&nbsp; The purification process is done by electrochemical and physical methods. The resulting synthesized material is characterized by UV Visible, FT-IR, and Raman Spectroscopy. The surface morphology of wrinkle paper shape is found by SEM and the size of the particles is determined by HR-TEM techniques. The layer distance of the starting material and the final product is been calculated by XRD analysis. Through TGA analysis it is found that the developed material is more stable at higher temperatures and subsequently it tends to be utilized in DSSC applications. The developed GO is coated on a glass plate using the spin coating technique with annealing in order to convert the normal glass into the conductive glass. And that conductive glass is used as a counter electrode for DSSC. The optimization of electrode resistance is done with the same annealing process by varying temperatures and the number of coatings.</p> shankar Amalaraj Copyright (c) 2021 shankar Amalaraj https://spast.org/techrep/article/view/976 Sat, 18 Sep 2021 00:00:00 +0000 Stable synthesis of Borophene as catalyst for hydrogen evolution reaction https://spast.org/techrep/article/view/956 <p>To overcome the shortage of fossil fuels, environmental pollution, and global energy demand,<br>there is a need for efficient, relatively cheap, earth-abundant, and clean energy sources which<br>can replace the traditional depleting energy resources. Hydrogen (H2) is a prime candidate<br>among all chemical fuels which has been in focus as an alternative to traditional fossil fuels<br>owing to its clean, environment-friendly, and zero-emission. Electrochemical water splitting is<br>the most efficient and cost-effective method to produce high purity hydrogen (H2) than other<br>existing methods. In hydrogen evolution reaction (HER), catalyst plays a major role. Currently,<br>precious metals such as Pt, Pd, etc., are being used as catalyst which are expensive, less<br>durable and can’t be produced in large scale. Extensive research is being carried out for the<br>low cost, and non-metal based catalysts such as transition metal oxides, chalcogenides,<br>phosphides, nitrides, metal alloys, and carbides.1 Among the various materials, twodimensional (2D) materials have important advantages that can be used as catalysts, they have a high specific surface area which is beneficial for sufficient exposure of active sites, the catalytic enhancement properties of 2D materials can be tuned by doping with transition metals or functionalizing the surface with other suitable derivatives.<br>Borophene is a single layer of Boron atoms, a recent member in the family of 2D materials.<br>Borophene is the lightest and thinnest elemental 2D material with a highly anisotropic surface<br>structure, which has gathered considerable interest since its discovery. 2 The α-Borophene and β-Borophene are found as the most stable. 3 The unique structure and bonding of borophene are responsible for its interesting properties. borophene could be an appealing electrocatalyst with high catalytic activity&nbsp; for hydrogen evolution reaction (HER), whose performances are compared with those of commercial Pt and MoS2. Several polymorphs of Borophene were<br>predicted by theory4, but there are only a few experimental realizations till date. We have synthesized the Borophene by using APCVD (Atmospheric pressure Chemical vapor deposition) and LPCVD (Low-pressure Chemical vapor deposition) by using boron trioxide,<br>MgB2, as a precursor material with Hydrogen and Argon as carrier gases. The reaction was<br>carried out at 1100 °C, grown on a different type of substrates like copper, Silicon, Aluminium,<br>etc., We have synthesized thicker Boron sheets on Silicon substrate to check the X-ray<br>diffraction pattern [Fig. 1] and observed the peaks of Boron phases.</p> <p>The structural and texture properties are characterized by using Glancing angle incidence Xray diffraction (GIXRD), Scanning electron microscopy (SEM), High-resolution transmission<br>electron microscopy (HR TEM), Raman spectroscopy, and atomic force microscopy (AFM).<br>The Current-Voltage measurements were done by using the Source measurement unit (SMU).<br>The elemental compositions of borophene were analyzed by using X-Ray photoelectron<br>spectroscopy (XPS). Our experimental findings will open up an alternative path for large scale<br>production of Borophene based 2D Layers for new energy devices.</p> Mohammed Abzal shaik Copyright (c) 2021 Mohammed Abzal shaik https://spast.org/techrep/article/view/956 Sat, 18 Sep 2021 00:00:00 +0000 A review on Exploration of red phosphors for the fabrication of phosphor-converted LEDs for Indoor Farming https://spast.org/techrep/article/view/1117 <p>The World Population Prospects 2019: ‘Highlights’, ‘published by the Population Division’ of the ‘UN Department of Economic and Social Affairs’, reports that the world population could reach its peak around the end of the current century, at a level of nearly 11 billion. This increase will need to be accompanied by increases in food production, and that too in a world where arable land is becoming an increasingly scarce resource. To address this problem, a relatively new agricultural practice known as Vertical Indoor Farming (VIF), which relies on height, rather than width, to generate agricultural production has emerged as a form of ‘sustainable cultivation of plants’. Harnessing this VIF technology, Indoor Farms are attracting significant attention in various countries. Light provides the energy for suitable ambient temperature and photosynthesis processes for plant growth, is considered to be one of the indispensable environmental parameters for plant growth and development [1]. Light is not only the essential energy source for photosynthesis in plants, but also affects several developmental processes, including seed germination, flowering, fruiting and other morphogenesis in plants. To supply the energy needed for plant growth, light emitting diodes (LEDs) have become primary artificial light sources with the advantages of high brightness, good reliability, excellent adjustability, low power consumption and long lifetime compared to traditional forms of artificial lighting such as metal halide lamps, fluorescent lamps, incandescent lamps, as well as high pressure sodium lamps. Fig. 1(a) shows the optical absorption spectra of chlorophyll a and chlorophyll b. From this figure it is evident that chlorophyll a and chlorophyll b absorb red light ranging from 600 nm to 700 nm wavelength. On the other hand, red emission from AlGaInP red LED chip is comprised of rather narrow emission spectra from 625 nm – 640 nm as displayed in Fig. 1(b) [2]. In Phosphor-converted red LED, red emission from 600 nm to 700 nm can be obtained by changing the composition of the phosphor. In this review, we elucidate a series of transition metal (Cr<sup>3+</sup>/Mn<sup>4+</sup>) / rare-earth (Eu<sup>2+</sup>) doped silicate and aluminate phosphors emitting in the red region (600 nm – 700 nm) exhibiting high luminescence efficiency for the fabrication of phosphor-converted red LED, which can be mounted on blue LED chip. Consequently the red LED, which will be fabricated by using these red emitting phosphors mounted on blue LED chip will provide the red light in 600 nm to 700 nm region, which can be absorbed by Chlorophyll a and Chlorophyll b. Solution synthesis mediated approaches will be discussed for the synthesis of these high efficiency phosphors.</p> Dr. Jyoti Rawat Copyright (c) 2021 Dr. Jyoti Rawat https://spast.org/techrep/article/view/1117 Tue, 21 Sep 2021 00:00:00 +0000 Structure and dielectric studies of Lanthanum oxide activated niobium-barium titanate for energy storage applications https://spast.org/techrep/article/view/1603 <p>High energy storage density and efficacy of dielectric capacitors are engaged to satisfy the requirements of advanced electronic and electrical systems for reduction. In general, three classes of ceramic materials alongside linear dielectrics, antiferroelectrics (AFEs), and ferroelectrics (FEs) are realistic in dielectric capacitor field [1].</p> <p>Ferroelectric behaviour with a perovskite structure barium titanate (BT) is a prominent material in the field of electronic industry. The properties that are exhibited by these materials are based on their ferroelectric phase transition. A small concentration substitution for Ba<sup>2+</sup> ions and Ti<sup>4+</sup> ions with equivalent to their radius could drive to the structure and morphology which influence further the properties of dielectric and then ferroelectric. The magnitude of diffuseness of the transition could demonstration the regular change from classical ferroelectric to diffuse ferroelectric or to relaxor, depending on the type of dopant incorporated in the BT lattice [2]. The substitution of Ba<sup>2+</sup> ions by the smaller ionic radius of lanthanum (La<sup>3+</sup>) cation ions on the A-site and the existence of B-site vacancies result in a rapid decrease in Curie temperature (<em>T<sub>c</sub></em>) [3]. lanthanum-doped dielectric materials usually fabricated in the oxygen environment. These materials electrical insulating property and curie temperature <em>T</em><sub>c</sub> is decreased with the increase of La concentration and are produced in white colour. Comprehensive electrical-property measurements described which demonstrate a smooth variation in dielectric properties from classic, first-order ferroelectric to paraelectric phase transitions for x &lt; 0.10 to diffuse phase transitions and relaxor-type behaviour for x &gt; 0.10 [4].</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; In the present work, structural, morphological and electrical properties of 10 mol% of La<sub>2</sub>O<sub>3</sub> activated niobium barium titanate Ba<sub>50</sub>Ti<sub>30</sub>O<sub>3</sub>Nb<sub>10</sub>La<sub>10</sub> (BTNb<sub>10</sub>La<sub>10</sub>) have been prepared by solid state reaction procedure with calcination and sintering temperatures of 1100 <sup>o</sup>C for 8 h and 1300 <sup>o</sup>C for 6 h, respectively. A 0.5 wt% of paraffin was added to these calcined powders as a binder medium at room temperature to fabricate few fine cylindrical discs by steel dies upon the application of a 10 MPa of hydraulic pressure. Polished discs were coated with conductive silver used for electrical studies.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; X-ray diffraction (XRD) pattern of BTNb<sub>10</sub>La<sub>10</sub> confirmed in the diffraction pattern for the angle between 42<sup>o</sup>–46<sup>o</sup> with indices (002) and (200) suggests tetragonal crystal symmetry at room temperature. Addition of La<sup>3+</sup> ions have made a band at 795 cm<sup>-1</sup> towards lower energy region in BTNb<sub>10</sub>La<sub>10</sub>. In the Fourier transform infrared (FTIR) spectrum, Ba-O-Ti/Nb/La bonds were revealed below 600 cm<sup>-1</sup>. The Raman bands revealed in the Raman spectrum around 758 cm<sup>−1</sup> and 311 cm<sup>−1</sup> shown in Fig.1 (a) are specific to the tetragonal phase of the BTNb<sub>10</sub>La<sub>10 </sub>material are associated to{<em>E</em>(LO), A<sub>1</sub>(LO)} {B<sub>1</sub>, <em>E</em>(TO+LO)} phonon mode. Average crystallite size of the BTNb<sub>10</sub>La<sub>10</sub> dielectric is 155 nm was estimated using scanning electron microscope (SEM) by Image-J software. Rod like morphological structure was revealed in the SEM images due to the formation of BT nanorods. In the dielectric constant vs frequency plot, at lower frequency, all types of polarization can exists owing to sufficient time of dipole moment, however, as the frequency is increased various polarizations will filter out. The reason behind this is accredited to the decrease of e<sub>r</sub> with frequency. Nyquist plot of BTNb<sub>10</sub>La<sub>10 </sub>does not contain any semicircles are as the frequency increased. Typically, the promising high energy density materials are relaxor-ferroelectric and antiferroelectric materials owing to their high <em>P</em><sub>max</sub> and low <em>P</em><sub>r</sub>. Recoverable energy storage density (<em>W</em><sub>rec</sub>) of BTNb<sub>10</sub>La<sub>10 </sub>ferroelectric is estimated as 0.06728J/cm<sup>3</sup> and energy loss (<em>W</em><sub>rec</sub>) 0.0035J/cm<sup>3</sup>. Owing to large <em>W</em><sub>rec</sub> of BTNb<sub>10</sub>La<sub>10</sub> dielectric material shown in Fig.1 (b). will be a superior material for energy storage applications.</p> Ravi Nirlakalla Copyright (c) 2021 Ravi Nirlakalla https://spast.org/techrep/article/view/1603 Fri, 08 Oct 2021 00:00:00 +0000 Effect of RBI Grade 81 on strength characteristics of Expansive soil https://spast.org/techrep/article/view/1825 <p>Expansive soils which are generally termed as problematic soils cause swelling and shrinkage resulting in significant damage to the structures constructed on them. In this study an attempt is made to know the effect of Road Building International Grade 81 (RBI Grade 81) on strength characteristics of expansive soil. RBI Grade 81 has a wide range of response spectrum. Response spectrum is the range of soils for which a particular stabilizer can be used. A wide range of tests such as Atterberg limits, Compaction, Unconfined compressive strength and California bearing ratio were conducted on expansive soil and&nbsp; expansive soil treated with various percentages of RBI Grade 81. The results indicate that RBI Grade 81 is effective in improving engineering properties of expansive soil.</p> VENUGOPAL G Copyright (c) 2021 VENUGOPAL G https://spast.org/techrep/article/view/1825 Sat, 09 Oct 2021 00:00:00 +0000 An Investigation on high energy ion irradiation induced modifications in one-dimensional nanostructure https://spast.org/techrep/article/view/2052 <p>Tuning of material properties remains of great research interest as a promising way to achieve maximum efficiency out of a device. Crystalline structure, morphology and electronic structure are the key factors that determine the physicochemical properties of a material. Therefore, the material performance can be tuned by modifying the structures and morphology. In this context, various techniques such as doping, heterojunction formation, functionalization, dye sensitization, etc. have widely been explored. However, searching for a unique modification technique to selectively tune the properties of the material remains of great interest to researchers.&nbsp; High energy (in MeV) ion irradiation is a unique technique, which transfers an enormous amount of energy (~keV/nm) by an inelastic interaction while passing through a material that causes intense electronic excitations in a cylindrical zone around its trajectory. When the energy transferred from the ion leads to an increment of the lattice temperature that exceeds the melting point, the material melts as a result of a localized thermal spike in the surrounded region of the ion trajectory. A re-solidification by rapid quenching of the molten state within picoseconds leads to a distortion in the crystalline structure of the material inside the cylindrical zone. The region is about a few nanometres in diameter around the ion trajectory, known as ion track. Further, the extent of structural modification by high-energy ion irradiation depends on the type and energy of the irradiating ion, the fluence (ions/cm<sup>2</sup>) and the target material. Hence, this technique enables to controllably alter the material properties in a localized manner.</p> <p>Titanium dioxide (TiO<sub>2</sub>) is a widely used semiconducting material in various applications such as solar energy harvesting, biomaterials, cosmetics and dyes and pigments. In recent decades, one-dimensional nanostructures such as nanotube, nanorod, nanowire gained much attention because of their unidirectional charge transport property and high surface to volume ratio. SHI irradiation-induced structural changes and phase transformations [1‒6] are reported on TiO<sub>2</sub> films. A few studies are also reported on SHI-induced nano or microlithography, ion track formation in single-crystalline rutile TiO<sub>2</sub> with certain orientations [7-11]. However, studies on one-dimensional TiO<sub>2</sub> nanostructures under the influence of SHI irradiation remain unexplored. Therefore, it is interesting to investigate the effect of SHI irradiation-induced localized modification in TiO<sub>2</sub> nanostructures.</p> <p>Here, we propose an investigation on high-energy ion irradiation on TiO<sub>2</sub> nanostructures. Our plan is to use localized thermal spike induced by high energy ion irradiation to controllably alter the physicochemical properties of TiO<sub>2</sub> nanostructures. Therefore, we have chosen a certain type of ion with a certain energy that leads the localized temperature of the material to rise above its melting point. Further, a long-range of the energetic ion passes through the nanostructure thickness without being implanted/ doped into the region of interest. The range of the energetic ion inside the target material is calculated using the SRIM code [12]. The resultant modification is expected to reveal some unique changes in the material properties of the TiO<sub>2</sub> nanostructures as the small lateral dimension (few tens of nanometer) of the nanostructure provides limited space for thermal energy transfer and atomic displacement in the radial direction.</p> Sutapa Dey Copyright (c) 2021 Sutapa Dey https://spast.org/techrep/article/view/2052 Sat, 09 Oct 2021 00:00:00 +0000 Effect of Sintering Temperature on structural, morphological and magnetic properties of Mn0.3Co0.2Zn0.5Fe2O4 Ferrite https://spast.org/techrep/article/view/416 <p>In the course of recent years, our society is dealing with extreme issues related to energy storage in small dimensions. However, the development of energy storage systems is lingering behind the fast progression in electrical-powered industries. Convenient electronic gadgets like cell phones, PCs, smartwatches, and so forth request the utilization of energy storage components which has lightweight, flexible, cost-effective, and environmentally friendly in nature [1]. The conventional capacitor and battery have been broadly utilized as energy storage devices inferable from the minimal expense and better execution [2]. Considering the genuine energy demands of recent portable electronic devices, hybrid vehicles, and consumer electronics, an energy storage device such as conventional capacitors and batteries can't satisfy the demands completely. In addition, the conventional capacitors and battery both have their astounding benefits and negative marks. Compared with the batteries, the conventional capacitors have relatively high power densities and low energy density. On the other hand, a battery has a higher energy density and lower power density than a conventional capacitor [3]. With the quick development in the advancement of portable electronics devices, there has been a continually expanding interest for alternative energy storage devices which can bridge the gap between conventional capacitors and battery, and have a high energy density, power density, long cycle life, and fast charge-discharge rates than conventional capacitor and battery. The supercapacitor is a potential alternative means that have higher energy density than a conventional capacitor, higher power density than a battery, fast charge-discharge rates, long cycle, and shelf life [4]. By and by, rather than a battery and conventional capacitors, supercapacitors have been broadly used as portable electronic devices, memory backup systems, hybrid vehicles, and consumer electronics [5]. The electrochemical performance of supercapacitors exceptionally relies upon the active material, substrate, and electrolyte utilized in it.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Ruthenium oxide (RuO<sub>2</sub>) is one of the best-known electrode materials (active material) which yields a high value of specific capacitance, high electrical conductivity, and reversible charge-discharge properties but there arise some difficulties in the use of ruthenium oxide as an electrode material because it is highly toxic and too much expensive [6]. These above difficulties can be developed by the use of the potential candidate spinel ferrite (MFe<sub>2</sub>O<sub>4</sub>, M = Fe, Co, Ni, Cu, Mn, Zn, etc.) material/doped spinel ferrite (active material) for superior electrochemical activity as compared to single metal oxide because of the large scale production, low cost, flexibility in the structure and morphology, and eco-friendly nature. However, increasing supercapacitor performance is very much challenging.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; As compared with the literature in this field, there is no result on the synthesis and effect of sintering temperature on the structural, morphological, magnetic, and electrochemical properties of Mn<sub>0.3</sub>Co<sub>0.2</sub>Zn<sub>0.5</sub>Fe<sub>2</sub>O<sub>4</sub> ferrite nanoparticles.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; In the present study, our main objective is to synthesize Mn<sub>0.3</sub>Co<sub>0.2</sub>Zn<sub>0.5</sub>Fe<sub>2</sub>O<sub>4</sub> ferrite nanoparticles at different sintering temperatures (750, 950, and 1150 <sup>O</sup>C) with a simple sol-gel technique Fig. 1 involving less energy and low-cost metallic salt as raw materials. Various characterization techniques viz. XRD, FTIR, FESEM, EDX, and VSM were performed for investigating the structural, morphological, and magnetic properties of the ferrite nanoparticles. Taking in view of these above results the electrochemical properties can be further studied for energy storage applications.</p> <p>&nbsp;<strong>Fig. 1.</strong> Sol-gel auto combustion method for synthesis of Mn<sub>0.3</sub>Co<sub>0.2</sub>Zn<sub>0.5</sub>Fe<sub>2</sub>O<sub>4</sub> ferrite nanoparticles at different sintering temperatures (750, 950, and 1150 <sup>O</sup>C).</p> <p>&nbsp;</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; From all the synthesized samples the single-phase spinel structure with cubic symmetry (Fd-3m space group) was observed for the sample sintered at 1150 <sup>O</sup>C which was assured by the XRD studies as shown in Fig. 2. The crystallite sizes estimated utilizing Scherrer's formula affirms the nanocrystalline nature of the incorporated samples as reported in Table 1.</p> <p><strong>Fig. 2. </strong>X-ray diffraction pattern of Mn<sub>0.3</sub>Co<sub>0.2</sub>Zn<sub>0.5</sub>Fe<sub>2</sub>O<sub>4 </sub>samples.</p> <p><strong>Table 1. </strong>The interlayer spacing (d), lattice constant (a<sub>0</sub>), unit cell volume (V), and crystallite size (D) of Mn<sub>0.3</sub>Co<sub>0.2</sub>Zn<sub>0.5</sub>Fe<sub>2</sub>O<sub>4 </sub>samples.</p> <table width="785"> <tbody> <tr> <td width="157"> <p><strong>Sintering</strong></p> <p><strong>Temperature</strong></p> <p><strong>( <sup>O</sup>C )</strong></p> </td> <td width="157"> <p><strong>d </strong><strong>(</strong><strong>Å</strong><strong>)</strong></p> </td> <td width="157"> <p><strong>a<sub>0</sub>&nbsp; (</strong><strong>Å</strong><strong>)</strong></p> </td> <td width="157"> <p><strong>V (</strong><strong>Å</strong><strong>)<sup>3</sup></strong></p> </td> <td width="157"> <p><strong>D (nm)</strong></p> </td> </tr> <tr> <td width="157"> <p><strong>750</strong></p> </td> <td width="157"> <p>2.544</p> </td> <td width="157"> <p>8.437</p> </td> <td width="157"> <p>600.70</p> </td> <td width="157"> <p>18.1</p> </td> </tr> <tr> <td width="157"> <p><strong>950</strong></p> </td> <td width="157"> <p>2.545</p> </td> <td width="157"> <p>8.440</p> </td> <td width="157"> <p>601.25</p> </td> <td width="157"> <p>29.3</p> </td> </tr> <tr> <td width="157"> <p><strong>1050</strong></p> </td> <td width="157"> <p>2.549</p> </td> <td width="157"> <p>8.454</p> </td> <td width="157"> <p>604.23</p> </td> <td width="157"> <p>50.2</p> </td> </tr> </tbody> </table> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; FTIR spectra shown in Fig. 3 affirm the formation of spinel structure at 1150 <sup>0</sup>C by the appearance of characteristic vibrational bands near 400 and 600 cm<sup>-1 </sup>which corresponds to the octahedral or B-site and tetrahedral or A-site respectively [7].</p> <p><strong>Fig. 3.</strong> FTIR spectra of Mn<sub>0.3</sub>Co<sub>0.2</sub>Zn<sub>0.5</sub>Fe<sub>2</sub>O<sub>4 </sub>samples.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; FESEM micrograph measures particle size (average) in the nanoscale range by using ImageJ software and reveals the presence of grains that were agglomerated and having porous morphology as presented in Fig. 4.</p> <p><strong>Fig. 4.</strong> FESEM micrograph and particle size histogram of Mn<sub>0.3</sub>Co<sub>0.2</sub>Zn<sub>0.5</sub>Fe<sub>2</sub>O<sub>4 </sub>sample.</p> <p>&nbsp;</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; The stoichiometric proportions of the synthesized sample were confirmed by the EDX spectra as shown by Fig. 5.</p> <p><strong>Fig. 5. </strong>EDX spectra of Mn<sub>0.3</sub>Co<sub>0.2</sub>Zn<sub>0.5</sub>Fe<sub>2</sub>O<sub>4 </sub>sample at 1150 <sup>O</sup>C.</p> <p>&nbsp;</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; The M-H curve of the incorporated sample (Fig. 6) shows an S-shaped hysteresis curve which reveals characteristics similar to that of the ferromagnetic material [8]. VSM study reveals the increment in the saturation magnetization with the increase in the sintering temperature. The magnetic soft nature of the incorporated samples due to the low coercivity makes them suitable for electromagnetic radiation material [9] and power application [10]. The squareness ratio for all the synthesized samples was found to be less than 0.5 which reveals the interaction of nanoparticles by magnetostatic interactions [11].</p> <p><strong>Fig. 6. </strong>M-H curve of Mn<sub>0.3</sub>Co<sub>0.2</sub>Zn<sub>0.5</sub>Fe<sub>2</sub>O<sub>4 </sub>sample.</p> Hamnesh Mahajan, Amarjeet Kaur, Ajeet Kumar Srivastava Copyright (c) 2021 Hamnesh Mahajan, Amarjeet Kaur, Ajeet Kumar Srivastava https://spast.org/techrep/article/view/416 Wed, 15 Sep 2021 00:00:00 +0000 Effect of Throughflow on Marangoni Convection in Ferromagnetic Liquids with Variable Viscosity https://spast.org/techrep/article/view/1097 <p>The effect of surface tension and vertical throughflow in magnetic field and temperature sensitive liquid of Newtonian ferromagnetic type is examined. Combining shooting and Galerkin techniques the stationary critical eigenvalues are computed. On the ferroconvection onset, M<sub>3</sub>, non-buoyancy magnetic parameter and Pr (&gt;1), Prandtl number have no influence. For upward or downward directions dual effect of destabilizing or stabilizing the system is observed in the presence of vertical throughflow. Throughflow effect studied through Pe, Peclet number delays ferroconvection onset and is observed to be independent to flow direction. M<sub>1</sub>, the magnetic buoyancy number, and V, the variable viscosity parameters have destabilizing influences on the system. Ferrofluids being fascinating materials are used as constant agents for magnetic resonance imaging (MRI). The great variety of magnetic nanofluids prepared may be tailored for technological, biological, medical and material science applications.</p> <p>&nbsp;</p> Prakash R, Jayalatha G, G N Sekhar Copyright (c) 2021 Prakash R, Jayalatha G, G N Sekhar https://spast.org/techrep/article/view/1097 Tue, 21 Sep 2021 00:00:00 +0000 SCIENTOMETRIC ANALYSIS ON UTILIZATION OF AGRICULTURAL WASTE FOR BOARD AND PANEL PREPARATION https://spast.org/techrep/article/view/2281 <p>Agricultural wastes are common in the environment, posing a health and environmental risk. Natural insulating materials are becoming increasingly popular due to their environmental and health benefits. The objective of this study is to establish a precise technique for assessing science and technology development trends in panel and board building utilizing agricultural waste, with sustainability as the most significant element. A bibliographic technique based on the Scopus database was used to collect articles. Scientometric analysis to investigate the trends of these publications, such as keywords, journals, nations, and authors. The utilization of waste in energy-efficient structures has been an emerging study. The filter is done based on the panel and board as a keyword of the paper, and the observed properties are described in the study. The research is being carried out to gain a practical understanding of the various materials that have been used in the preparation of boards and panels, as well as the tests that will be carried out, such as modulus of rupture, modulus of elasticity, thermal conductivity, energy analysis, small hot box test, and life cycle assessment to assess energy usage and CO<sub>2</sub> emissions. The future scope has also been added in the conclusion.</p> Prerna Sharma Copyright (c) 2021 Prerna Sharma https://spast.org/techrep/article/view/2281 Thu, 07 Oct 2021 00:00:00 +0000 An Organic Solvent-Assisted Intercalation and Collection (OAIC) for Ti3C2Tx MXene with Controllable Sizes and Improved Yield https://spast.org/techrep/article/view/607 <p>Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> (MXene), a family of cutting-edge two-dimensional (2D) nanomaterials [1, 2], has a wide range of potential applications, including electromagnetic interference shielding [3], electrochemical energy storage [4, 5], catalysis [6], sensors [7], biomedicine [8], etc. As the building block of these important applications, more attention has currently been put on synthetic methods that can deliver the largescale demand of materials for real industrial applications. A good synthetic method of nanomaterials requires good controllability, high yield, low cost, green processes, and safety, which are the main factors in deciding that a synthetic method can leave laboratory demonstrations and go to mass production. Similarly, the continuous development of novel synthetic methods is present throughout the whole road-map of MXene materials [9]. Initially, Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> flakes were prepared by two steps including etching the Ti<sub>3</sub>AlC<sub>2</sub> (MAX phase) by concentrated hydrofluoric acid (HF) and then intercalating multilayered sheets with organic molecules, e.g., hydrazine, urea, and dimethyl sulfoxide (DMSO) (Route I in Fig. 1) [10]. However, the utilization of hazardous and toxic HF not only makes the operations risky, but the low yield ( 20%) [11] further suggests it could not possibly use in mass production. Later, a more moderate etching system was reported using the fluoride salt, LiF, mixed with HCl. In this system, HF is formed in situ with lithium ions intercalated during the etching process, resulting in Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> clay. After sonication in water, single Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> flakes with submicron lateral-size could be isolated (Route II in Fig. 1) [12]. The pros and cons are the avoidance of having to use HF, and the small size of Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> flakes with low yield, respectively. Recently, some further modifications have been developed to improve the yield and/or increase the size of Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> flakes [13-17].&nbsp;However, a method with a perfect trade-off that meets all the aforementioned requirements, inc., good controllability, high yield, low cost, green process, and safety, has to been achieved and remains challenging.</p> <p>In this work, a modified approach, organic solventassisted intercalation and collection (OAIC) is reported. The OAIC approach (Route III) is a modified method which combines a part of Route I and Route II, of which features include but not limited in the following ways.&nbsp;First, the LiF/HCl etching process is the same as Route II, which meets the moderate etching process.&nbsp;Second, intercalation is reinforced by DMSO, which is similar as most intercalating chemicals in Route I. Third, the well-known similia similibus solventur principle is adopted to remove the residual DMSO by DCM because the magnitude of solvent solvent interactions is much larger than solvent-nanoflakes interactions [18].&nbsp;In addition, the low boiling point of DCM (39.75 C at 760 mmHg) is what help DCM to volatilize by vacuum drying.&nbsp;Most significantly, inspired from the fabrication of graphene and Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> macro-fibers [19, 20], DCM washing efficiently restrain large weight loss in Route I which is caused by the step of water adding for removing DMSO because of the strong interactions between water and Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> flakes.&nbsp;After adding DI water, Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> flakes can be brought down from the supernatant by centrifugation (3500 rpm).&nbsp;The sediment can have DMSO added to further intercalate the residues, in which more Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> flakes can be extracted after DCM washing and centrifugation in water to enhance the yield.&nbsp;This step can be cycled at least 6 times;&nbsp;each cycle accumulates more Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> flakes with increased size in gradients, which is the fourth feature of OAIC approach and the first reported feature among all other approaches. The OAIC approach is reported to prepare Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> flakes in gram-level with enhanced yield (46.3%) and improved quality (area reaches ca. 4.60 μm<sup>2</sup>) through a facile approach featuring sonication-free and high-speed centrifugation-free (&lt;&nbsp;4000 rpm) methods. More importantly, the Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> flakes of different sizes can be obtained in different production cycles instead of gradient centrifugation.&nbsp;The Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> flakes with median size show the outstanding capacitive and rate performance.&nbsp;To our best knowledge, the OAIC approach that simultaneously meets aforementioned features of a good synthetic method is a novel procedure, which could shed new light on the mass production of other MXene materials in the future.</p> Danyao Qu Copyright (c) 2021 Danyao Qu https://spast.org/techrep/article/view/607 Sun, 19 Sep 2021 00:00:00 +0000 The Studies on Partial Replacement of Cement by Eucalyptus Ash in Concrete https://spast.org/techrep/article/view/2792 <p>Cement composites have become an inevitable part of the construction industry. Concrete is the most utilized material on earth next to the water. With the advent of urbanization and increase in infrastructure activities, consumption of cement concrete has escalated. The production process of one ton of cement emits about 0.7 tons of carbon-dioxide into the atmosphere. The emitted carbon dioxide will lead to the greenhouse effect causing global warming[1]. This in turn affects the rainfall pattern, melting of ice caps, and rise in sea levels. Hence there is a need to mitigate the use of cement and make the development sustainable.</p> <p>Eucalyptus trees were grown across the Karnataka state in India as a part of afforestation in the recent past. However, it was recently proved that eucalyptus trees would suppress the groundwater table as it needs about 90 liters of water per day. Thus its cultivation was restricted by law and the same is being used for firewood and burning of bricks. Still, these are available in abundance and hence it has become an economical fuel source at the countryside. It acts as a source of bio-mass and curtails the use of non-renewable sources of energy[2]. The ash produced by the burning activity is either dumped in landfills which creates soil and air pollution in the neighborhood.&nbsp; This ash contains cementitious property and it can be used along with cement[3]. Confining its movement in the concrete would reduce the usage of cement, air pollution, and exploitation of natural resources[4].</p> <p>In this research, a concrete mix of M20 grade was designed according to IS: 10262-2000 for moderate exposure conditions. 53 grade ordinary Portland cement (OPC), river sand, and 20mm down size crushed stone coarse aggregates were used to prepare the concrete. 1:1.71:2.78 mix proportion was finalized for the workability of 75-100mm slump with 0.5 water-cement ratios.&nbsp; To make the concrete eco-friendly, cement was partially replaced by eucalyptus ash at 20, 40, 60, and 80%. The fresh concrete property was determined by the slump cone test, which depicts that workability reduces with an increase in replacement levels of eucalyptus ash. Mechanical properties of concrete were determined by compression, split tensile, and flexural strength tests at 3, 7, 28, and 56 days. Mechanical properties proved that eucalyptus ash can be used as a supplement to cement up to 20%. At 20% replacement, concrete exhibited maximum compressive strength of 31.39 MPa on the 28<sup>th</sup> day. After 20% replacement, the strength of concrete decreased gradually and it didn’t reach the target mean strength. Split tensile strength and flexural strength were almost proportional to compressive strength. It was noted that the density of concrete reduced with an increase in replacement levels due to the low specific gravity of eucalyptus ash. Water absorption increased with the increase in ash replacement levels. Microstructure analysis also proved that, by replacing eucalyptus ash up to 20%, concrete can be made sustainable when compared to conventional concrete. Thus, eucalyptus ash acts as a reliable source of supplement for OPC, and by the use of the same, OPC composites will be eco-friendly and boost sustainable development.</p> SACHIN K C Copyright (c) 2021 SACHIN K C https://spast.org/techrep/article/view/2792 Sun, 17 Oct 2021 00:00:00 +0000 A Review Banana Fibre as Reinforcement in Green Composites https://spast.org/techrep/article/view/2405 <p class="p1">Composite materials have become increasingly popular in a variety of applications in recent years. It is not surprising that natural fibre-reinforced composites are attracting the attention of academics all over the world due to their advantages over glass fibre composites, which include low density, environmental friendliness, cost savings, and the ability to be used in a variety of applications. The goal of this review paper is to provide a complete overview of banana fibre-reinforced composites as well as their diverse applications. It also goes into the factors that influence the properties of Banana Fibres, such as fibre configuration, length, orientation, surface treatments done to the fibres, temperature, and moisture content. This review should aid aspirant researchers working on the subject of Natural Fibres in comprehending many aspects of Banana Fibre processing and its various properties. Composites are materials made up of two or more chemically distinct constituents on a macroscopic scale, separated by an interface. To form a composite, one or more discontinuous phases are embedded in a continuous phase. The discontinuous phase is usually tougher and stronger than the continuous phase and is called the reinforcement, whereas, the continuous phase is termed as the matrix [1–3]. The matrix material can be metallic, polymeric or ceramic. When the matrix is a polymer, the composite is called polymer matrix composite (PMC). The reinforcing phase may be fibrous or non-fibrous (particulates) in nature, and natural-fibres are fibres that are produced from plants or other living organisms. Fibre reinforced polymers (FRPs) are made up of high-strength, high-modulus fibres<span class="Apple-converted-space">&nbsp; </span>bonded to a matrix with a distinct interface and Both fibres and matrix maintain their physical and chemical identities in this state. The matrix holds Fibres that are the primary load-carrying members at the optimal location and orientation, serves as a load transfer medium between them, and protects them from environmental damage [4–7]. While polymeric composites have numerous advantages, the lack of adequate degradation of these materials remains a significant challenge. Furthermore, the manufacturing of artificial polymers (such as polypropylene (PP), polyethylene, and others) requires a large amount of oil-based resources, the majority of which are nonrenewable. Thus, in order to limit the use of nonrenewable and diminishing oil reserves, scientists are investigating sustainable and environmentally friendly alternatives. According to the Energy Information Administration, oil production is expected to decline by 4% per year after 2010.As a result, several attempts are made to find environmentally sustainable alternatives in order to address the requirements. [8]. The idea of "green composites" evolved to develop newer eco-friendly materials with engineering and commercial applications as well as a variety of techno-economic benefits. Composites reinforced with natural fibres are attracting more research attention because of their ease of use, recyclability, light weight, and low cost [9].As a result, natural fibres are becoming more common as people become more environmentally conscious. Not only can bio-composites help with environmental concerns, but they can also help with packaging industry problems if they are reinforced with different grades of polymers to improve their numerous properties and used for sustainable constructions in the automobile industry[10]. Natural fibres such as banana, coir, hemp, sisal, kenaf, and flax are better components for fibre-based polymer composites because they are biodegradable, reusable, and readily available.<span class="Apple-converted-space">&nbsp;</span></p> <p class="p1">Banana (Musa Sapientum) is a well-known fruit crop that is grown in many tropical areas around the world. After harvesting the fruits, a large amount of biomass is wasted.These wastes can provide additional income to cultivators because the fibres harvested from them can be used, thereby helping to improve the country's rural economy. Banana fibre is ideal for use as a reinforcement material because of its high cellulose content (64 wt%) and low micro-fibrillar angle (11°) [11].The tensile strength, precise flexural strength, and rotting resistance of banana fibre are comparable to those of glass fibres [12].All of these factors contribute to make Banana Fibres one of the most extensively reviewed Natural Fibres for “Sustainable Composites.”</p> Shresth Singh Copyright (c) 2021 Shresth Singh https://spast.org/techrep/article/view/2405 Mon, 11 Oct 2021 00:00:00 +0000 Phase Transition in PVDF-TrFE/Hyperbranched Polyester (90/10) Blend Thin Film during Heating-Cooling Cycle using FTIR Spectroscopy https://spast.org/techrep/article/view/283 <p>Ferroelectric polymers such as polyvinylidene fluoride (PVDF) and its copolymer with trifluoroethylene (TrFE) have been widely used as energy-harvesting nanogenerator and non-volatile memory device [1-3] because of their flexible film forming nature as well as piezoelectric [4] and ferroelectric [5] characteristics, respectively. Compared to neat PVDF, the PVDF-TrFE copolymer is expensive but considered as superior to PVDF in terms of higher crystallinity, remnant polarization and piezoelectric response. PVDF-TrFE exhibits β-crystalline phase spontaneously, whereas PVDF requires either mechanical drawing of the α-phase, casting from high polar solvents, electrical poling or crystallization from melt for exhibiting higher β-crystalline phase. Hence, the focus of researchers working in this field is to study the crystalline phase transition in PVDF-TrFE and the ways to enhance the ferroelectric β-crystalline phase in PVDF-TrFE suitable for flexible electronic applications. Many research groups have used additives such as metal oxides [6], CNT [7], nanoparticles [8], etc. in PVDF-TrFE to improve its ferroelectric crystalline phase, to study the polymorphic changes and to reduce its cost of usage in electronic applications. Considering the aforementioned characteristics, in the present work, we have studied the crystalline phase transition changes in spun-cast PVDF-TrFE/hyperbranched polyester (HBP) (90/10 wt.%) blend film deposited on KBr substrate (designated as Blend-AC sample) and annealed at 130 oC (designated as Blend-AN sample). Our first objective is to study the phase transition behavior of the blend sample by subjecting the blend AC and AN thin film samples to heating-cooling (30→120→30 oC) cycle by FTIR-Transmission Spectroscopy (TS). From FTIR data, it was found that the absorption intensity of A1 band at 1289.5 cm-1 for AC and 1292 cm-1 for AN is decreased gradually during heating for both the samples. However, it is increased for 30C condition for AC sample whereas it comes to the initial intensity for AN sample for 30C condition. Fig. 1 shows the relative amount of ferroelectric crystalline phase for both AC and AN blend thin film samples as a function of heating-cooling cycle. The Blend-AC and Blend-AN thin film samples exhibit irreversible and reversible phase transitions, respectively. Our second objective is to apply Factor analysis of FTIR-TS heating-cooling data. It was found that the AN sample exhibited reversible phase transition (70%↔70%) while the AC sample displayed irreversible transition (50%↔70%).</p> <p><img src="https://spast.org/public/site/images/manand2021/picture1.jpg" alt="Fig.1. FTIR-TS: Relative amount of ferroelectric β-crystalline phase in PVDF-TrFE/HBP (90/10) blend thin film sample (a) AC and (b) AN as a function of heating-cooling cycle." width="681" height="256"></p> <p>Fig.1. FTIR-TS: Relative amount of ferroelectric β-crystalline phase in PVDF-TrFE/HBP (90/10) blend thin film sample (a) AC and (b) AN as a function of heating-cooling cycle.</p> <p>Acknowledgement: This work was supported by the Industrial Strategic Technology Development Program (Grant No. 10047976) funded by the Ministry of Trade, Industry &amp; Energy (MOTIE, KOREA). One of the authors (A.A.P) also wish to thank CSIR, Government of India for supporting this study under CSIR-EMR-II scheme (03(1450)18/EMR-II dt.05-06-2018).</p> Manjula Dhevi Dhevagoti, Sathiyanathan Ponnan, Anand Prabu Arun, Hongdoo Kim Copyright (c) 2021 Manjula Dhevi Dhevagoti, Sathiyanathan Ponnan, Anand Prabu Arun, Hongdoo Kim https://spast.org/techrep/article/view/283 Sat, 11 Sep 2021 00:00:00 +0000 GEOSYNTHETIC ENCASED CONCRETE DEBRIS STONE COLUMNS https://spast.org/techrep/article/view/397 <p>Rapid urbanization and growth of infrastructure in the present days has resulted in dramatically increased demand for land space. This has compelled building industry to improve the soft soil grounds which otherwise are unsuitable for construction activities. Ground improvement is the modification of foundation soils or project earth structures to provide better performance under operational loading conditions. Structures constructed on soft soil experience several problems like excessive settlements, large lateral flow of soft soil beneath the structures and loss of global or local stability. The various techniques used to improve the engineering properties of soil are densification technique, Reinforcement technique, Stabilization technique, miscellaneous methods amongst these various ground improvement techniques used, stone columns and geo synthetic reinforcement are probably the most popular ones. This is primarily due to their simplicity, ease of construction and overall economy that finds favor with the practicing engineers.</p> <p>The growing quantities and types of waste materials, shortage of landfill spaces, and lack of natural earth materials highlight the urgency of finding innovative ways of recycling and reusing waste material additionally; recycling and subsequent reuse of waste materials can reduce the demand for natural resources, which can ultimately lead to a more sustainable environment. The resources such as coarse aggregates, sands and cements will be at a disadvantaged position, as these resources are not able to cope with the high demand in the construction industry. Therefore, utilizing the recycled aggregate may be one of the significant efforts in achieving a sustainable construction. Keeping this in mind, tests are conducted on crushed concrete debris so that natural aggregate are replaced by crushed concrete debris.</p> <p>The aim of this experiment is to use crushed concrete debris (CCD) in soil stabilization. A series of experiments are to be carried out to develop an understanding on the performance of soft clay foundation beds reinforced using geo synthetic encased stone – concrete debris column. Model tests will be conducted on clay reinforced with encased vertical columns filled with both CCD and aggregates and a comparative study is to be done as shown in table 1 and an assessment of ultimate bearing capacity of the composite ground is to be done. The column failure mechanism in the both the cases are to be carefully studied.Table 1. Modal Tests and later Numerical analysis is done in PLAXIS 2D is used for analysing the behaviour of geo synthetic encased stone column stabilised clay bed numerically.Analyses were carried out using Mohr-Coulomb’s criterion considering elastoplastic behaviour for soft clay, stones, and sand. An undrained behaviour is assumed for all the materials. Lab conditions were simulated in plaxis for accurate comparison for same model tests shown in Table 1</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>Table 1.: Model Tests</p> <table width="609"> <tbody> <tr> <td width="83"> <p>Model test</p> </td> <td width="139"> <p>Column type</p> </td> <td width="117"> <p>Material used</p> </td> <td width="51"> <p>L/D</p> </td> <td width="111"> <p>Loading type</p> </td> <td width="107"> <p>Encasement</p> </td> </tr> <tr> <td width="83"> <p>1</p> </td> <td width="139"> <p>End bearing</p> </td> <td width="117"> <p>CCD</p> </td> <td width="51"> <p>7</p> </td> <td width="111"> <p>Full area</p> </td> <td width="107"> <p>60%</p> </td> </tr> <tr> <td width="83"> <p>2</p> </td> <td width="139"> <p>End bearing</p> </td> <td width="117"> <p>CCD</p> </td> <td width="51"> <p>7</p> </td> <td width="111"> <p>Full area</p> </td> <td width="107"> <p>100%</p> </td> </tr> <tr> <td width="83"> <p>3</p> </td> <td width="139"> <p>End bearing</p> </td> <td width="117"> <p>CCD</p> </td> <td width="51"> <p>5</p> </td> <td width="111"> <p>Only column</p> </td> <td width="107"> <p>100%</p> </td> </tr> <tr> <td width="83"> <p>4</p> </td> <td width="139"> <p>End bearing</p> </td> <td width="117"> <p>Aggregates</p> </td> <td width="51"> <p>5</p> </td> <td width="111"> <p>Full area</p> </td> <td width="107"> <p>100%</p> </td> </tr> <tr> <td width="83"> <p>5</p> </td> <td width="139"> <p>Floating</p> </td> <td width="117"> <p>CCD</p> </td> <td width="51"> <p>5</p> </td> <td width="111"> <p>Full area</p> </td> <td width="107"> <p>60%</p> </td> </tr> <tr> <td width="83"> <p>6</p> </td> <td width="139"> <p>Floating</p> </td> <td width="117"> <p>CCD</p> </td> <td width="51"> <p>5</p> </td> <td width="111"> <p>Full area</p> </td> <td width="107"> <p>100%</p> </td> </tr> <tr> <td width="83"> <p>7</p> </td> <td width="139"> <p>Floating</p> </td> <td width="117"> <p>CCD</p> </td> <td width="51"> <p>7</p> </td> <td width="111"> <p>Full area</p> </td> <td width="107"> <p>60%</p> </td> </tr> <tr> <td width="83"> <p>8</p> </td> <td width="139"> <p>Floating</p> </td> <td width="117"> <p>CCD</p> </td> <td width="51"> <p>7</p> </td> <td width="111"> <p>Full area</p> </td> <td width="107"> <p>100%</p> </td> </tr> <tr> <td width="83"> <p>9</p> </td> <td width="139"> <p>End bearing</p> </td> <td width="117"> <p>CCD</p> </td> <td width="51"> <p>5</p> </td> <td width="111"> <p>Full area</p> </td> <td width="107"> <p>60%</p> </td> </tr> <tr> <td width="83"> <p>10</p> </td> <td width="139"> <p>End bearing</p> </td> <td width="117"> <p>CCD</p> </td> <td width="51"> <p>5</p> </td> <td width="111"> <p>Full area</p> </td> <td width="107"> <p>100%</p> </td> </tr> <tr> <td width="83"> <p>11</p> </td> <td width="139"> <p>No column</p> </td> <td width="117"> <p>-</p> </td> <td width="51"> <p>-</p> </td> <td width="111"> <p>Full area</p> </td> <td width="107"> <p>-</p> </td> </tr> </tbody> </table> prathyusha tenepalli Copyright (c) 2021 prathyusha tenepalli https://spast.org/techrep/article/view/397 Fri, 17 Sep 2021 00:00:00 +0000 Electrochemical corrosion behaviour of nickel and nickel-reduced graphene oxide coatings on mild steel in 3.5% NaCl solution https://spast.org/techrep/article/view/1449 <p>Nickel-based electrodeposits are extensively used to protect mild steel. The graphene-based materials as corrosion resistive coatings for metallic substrates have been attracted researchers due to their ability to prevent the metal surface.&nbsp;Herein, nickel and nickel reduced graphene oxide (Ni-rGO) composite coatings have been electrodeposited on mild steel using sulphate bath solution. The Ni-rGO coating was prepared in presence of reduced graphene oxide sheets. The rGO nanosheets were co-deposited along with the nickel on the mild steel surface. &nbsp;The morphological results reveal that the Ni-rGO coatings exhibited a smaller grain size with less surface defects. It was observed from the scanning electron micrographs images that composite coating’s are porous free. The anti-corrosion properties of coatings were further examined by salt spray test.</p> <table> <tbody> <tr> <td width="68">&nbsp;</td> </tr> <tr> <td>&nbsp;</td> <td>&nbsp;</td> </tr> </tbody> </table> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p><strong>&nbsp;</strong></p> <p><strong>&nbsp;</strong></p> <p><strong>&nbsp;</strong></p> <p>&nbsp;</p> <p><strong>Fig.1.</strong> <strong>XRD patterns of&nbsp; GO and rGO (a), SEM images for GO (b) and rGO (c).</strong></p> <p>&nbsp;</p> <p>&nbsp;</p> <p>Electrochemical anodic polarization behavior was performed for the nickel and Ni-rGO coatings. Fig. 2 represents anodic polarization curves for the nickel and Ni-rGO coatings in an aqueous 3.5% NaCl solution.</p> <p><strong>&nbsp;</strong></p> <p><strong>&nbsp;</strong></p> <p><strong>&nbsp;</strong></p> <p><strong>&nbsp;</strong></p> <p><strong>&nbsp;</strong></p> <p><strong>&nbsp;</strong></p> <p><strong>Figure 2. Anodic polarization curves for pure nickel and Ni-rGO coatings in 3.5% NaCl solution.</strong></p> <p>The electrochemical polarization and impedance measurements revealed that Ni-rGO coating can enhances the corrosion resistance of mild steel. Electrochemical measurements revealed that the insertion of a few-layered rGO to the Ni matrix increases the corrosion resistance properties of the Ni-rGO coatings. Ni-rGO coatings provide a physical barrier to the corrosion medium by rGO filling in the active micro-sites on the mild steel surface and hence it reduces metal dissolution. Also, the results have shown that rGO play important role in the formation of Ni-rGO coatings by controlling the deposition of nickel metal on mild steel.</p> DHARANENDRA R A, M Shet Prakash, S. Shivakumara, K V Jagannath Copyright (c) 2021 DHARANENDRA R A, M Shet Prakash, S. Shivakumara, K V Jagannath https://spast.org/techrep/article/view/1449 Thu, 07 Oct 2021 00:00:00 +0000 High oxide ion conductivity in Na0.5Bi0.5TiO3-BiFeO3-BaTiO3 based ferroelectric materials https://spast.org/techrep/article/view/1485 <p>An electrochemical device such as solid oxide fuel cells (SOFC) converts chemical energy to electrical energy by oxidizing a fuel such as hydrogen, hydrocarbons, or ammonia. SOFCs use an oxide material, primarily yttria-stabilized zirconia (Y0.16Zr0.84O1.92), as an electrolyte and operate at a temperature higher than 800 °C. This is due to the fact that most electrolyte candidates such as yttria-stabilized zirconia (Y0.16Zr0.84O1.92), gadolinium doped ceria (Gd0.1Ce0.9O1.95), Sr and Mg-doped lanthanum gallates (La0.8Sr0.2Ga0.8Mg0.2O3) show high oxide ion conductivity of ~ 0.01 S.cm<sup>-1</sup> only at higher temperatures (&gt; 800 °C) [1-3]. Lowering the operating temperature of SOFCs below 650 °C remains a key challenge to the scientific community [4]. Therefore, there is a need to explore materials with new structures that can meet the criteria such as high-oxide ion conductivity, stability over the operating temperature range, etc. Recently, ferroelectric materials such as perovskite Na0.5Bi0.5TiO3 (NBT) and Aurivillius phase of Bi4Ti3O12 show high oxide ion conductivity of 0.01 S.cm<sup>-1</sup> at lower temperatures (~ 600 °C) and are promising [5,6]. In this context, we have explored the Na0.5Bi0.5TiO3-BaTiO3-BiFeO3 ferroelectric system (fig.1). The materials design route using the ternary phase diagram provides us access to the required structure by tuning the composition, and various doping strategies and understanding structure-property relation. We have synthesized a series of compositions using the solid-state route as shown in the diagram (fig. 1a). We find that composition A (Bi0.44Na0.31Ba0.25Fe0.13Ti0.87O3) and composition B (Bi0.255Na0.125Ba0.62Fe0.13Ti0.87O3) forms with perovskite structure (fig. 1b and 1c). Impedance studies using a custom-built set-up show a bulk/grain conductivity of ~10<sup>-5</sup> S.cm<sup>-1</sup> and 10<sup>-3</sup> S.cm<sup>-1</sup> respectively for composition A and composition B respectively. The observed conductivity in composition B is higher than that of the parent compound Na0.5Bi0.5TiO3 (fig. 1d). We further employed various doping strategies to control oxygen vacancy and study their effect on conductivity. To introduce oxygen vacancy, we doped Mg, Sr, Nb at the A and B- sites of the perovskite and varied the Na/Bi, Na/Ba ratio. Further, we plan to employ powder neutron and X-ray diffraction to solve the average structure and correlate their average structures with the defect chemistry to explain their conductivity behavior. We believe the understanding from the present study will be helpful to identify the structure, dopants <em>e.g.</em>, donor vs acceptor at various sites, and design a new class of oxide ion conductors.</p> TULASIRAO PATNAYAKUNI Copyright (c) 2021 TULASIRAO PATNAYAKUNI https://spast.org/techrep/article/view/1485 Thu, 07 Oct 2021 00:00:00 +0000 Role of Nano-Cellulose in CO2 separation from biogas through facilitated transport membranes- A review https://spast.org/techrep/article/view/2621 <p>Nanocellulose (NC) have taken the limelight in the field of material science in the recent times because of the eco-friendliness and the high utility it offers[1]. Its application in membrane technology for multiple applications like gas separation, water purification etc are highly anticipated in the near future. This is because of the stricter restrictions which policy makers are putting in place to protect the environment. Thus, NC based composites has become a promising gas separation approach for CO<sub>2</sub> separation from biogas. Vast applications in gas separation are possible due to NC based composites working on facilitated transport mechanism (FTM) (see Fig 1). NC based membranes add great advantages like high specific surface area, surface modification possibility, environmental friendliness and excellent mechanical properties. The biodegradability, less toxicity, low density and strength property adds to the advantages to NC. However, NC based membranes for CO<sub>2</sub> separation are far less established due to the less exploration in this area. Due to this, the thoroughness of basic issues on NC based membranes is still not clear, and is presently an area of rigorous investigation. In this paper, a systematic review on the recent works conducted on NC based FTMs for CO<sub>2</sub> separation is done.</p> <p>The complete review is classified into three parts: (1): Converting biogas into biofuel- Here, the main areas covered includes the various biogas upgradation technologies –the focus is on the different types of technologies available in the market right now and the possible technologies coming up in the near future. It is classified on the basis of the energy needs, CH<sub>4</sub> purity and recovery they offer, the operational cost for each type etc. It is shown that absorption and adsorption techniques are having high (with a near 99%) CH<sub>4</sub> purity and recovery. The energy demands are shown to have more when compared to membrane technology [2]. The carbon footprint created by using membrane technology is also very less. The Investment cost for membrane technology is only 0.12 euro/Nm<sup>3</sup> which is very less compared to others. (2) The materials used in membrane technology are discussed with impetus given on polymers, inorganic membranes (metals, ceramic, zeolites) and mixed matrix membranes. Out of this, polymeric membranes are having less hazards, low energy consumption and green but less permeability and selectivity. The impartation of FT mechanism by the addition of carriers for the significant improvement of the outcomes in polymeric membranes is also discussed along with the type of carriers and classification of FTM [3]. Apart from that, the impact of nanofillers in polymeric membranes is also given weightage. The applications of 0D,1D,2D and 3D nanofillers (see Fig 2) are given in detail[4]. &nbsp;The types of membrane manufacturing methods suitable for each membrane materials, the classification of processes is also detailed. Dip coating is preferred for thin coating of nanocomposite over membranes. The importance of NC as a material, to be used for CO<sub>2</sub> separation, in the composite and the impact of the hydroxyl groups on the reactive surface of nanocellulose is highlighted here. The classification of nanocellulose and the comparison between these is also mentioned. (3) External variables affecting permeance and selectivity are detailed with the findings from the recent studies based on NC based FTMs. It is shown from the studies that RH being a major parameter helped in increase of CO<sub>2</sub> permeance in all the studies. A preferred RH of 90% is most mentioned considering the impact it has in selectivity also. Another parameter discussed is temperature effect[5]. Permeance increased for CO<sub>2</sub> because of the loosening of the membrane at high temperatures but it is shown that the selectivity decreased. Atmospheric temperature is suggested in some studies, as the optimum to opt for.</p> <p>Even though explored less, the impact of increasing pH by adding sodium hydroxide is also mentioned which was conducted in one study. Even though it is argued in the study that increasing pH is the reason for increase in the outcomes, it can be argued that the reason for improving permeance and selectivity due to increase in pH is due to the presence of hydroxyl groups in NaOH[6]. Feed pressure is another factor defined where its increase drastically reduced the outcomes. This trend is visible more in the high-pressure regions from 5 bar onwards[7]. The internal parameters of the membrane material are presented here. From the studies, thicker the membrane, lesser is the permeance of the membrane but selectivity of CO<sub>2</sub> increased[8]. Other parameters like NC concentration, Moisture uptake capacity and membrane strength are also briefed[9] [10]. Crystallinity restricted the CO<sub>2</sub> permeation through it, because of the high density they offer to the membrane. with the effects of different external and internal variables is presented.</p> <p>The effect of different compositions with NC based membranes in the recently conducted studies and the future scope in the areas of improvement is also chalked out.</p> SANDEEP AHANKARI Copyright (c) 2021 SANDEEP AHANKARI https://spast.org/techrep/article/view/2621 Sun, 17 Oct 2021 00:00:00 +0000 Experimentation of switched reluctance motor with prototyping composite core blanks https://spast.org/techrep/article/view/2732 <p>Abstract: Soft Magnetic Composite (SMC) materials and their constituent electromagnetic apparatuses have undergone a significant change in the last decade. The basis for soft magnetic composites is bonded iron powder which is coated, pressed into a solid material using a die. However, it has the drawback that the properties will be different from those obtained from compaction and machining process. To investigate “Pre-fabricated or Pre-form SMC blanks” products, this paper presents the analysis of a Switched Reluctance Motor (SRM) with pre-fabricated SMC blanks of low mass density. The fast and low cost approach is to machine the component from a pre-form or prototyping blanks. Finite Element Analysis (FEA) study has been deployed to determine key motor parameters, and performance predictions are validated through experimental results on a prototype model.<br>Introduction: (SMC) materials are nothing but iron powder particle material where in a continuous oxide layer insulates the surface of every particle. Along with a lubricant and a binder at a high pressure the iron powder particles are compacted to result a bulk material [1]-[3]. The lubricant facilitates the compaction and ejection while the binder invigorates the SMC material by strengthening it. The insulation between the particles is imparted by the lubricant and the binder material. The internal stress generated during compaction can be relieved through curing – a heat treatment process. The major drawback of SMC compared to lamination material is the smaller permeability (maximum 800 vs. &gt;3000). It has higher iron losses at practical frequencies [2]. SMC material has the following advantages: 1) improved overall thermal loading of the motor, 2) reduced vibration and allied acoustic noise due to the cushioning nature of insulation binder between the iron powder particles of the material. The iron powder Somaloy 1000 3P with the lubricating binder 0.3% 3P lube is considered since it could be more easily machined with better physical properties compared to the SMC using the lubricant 0.5% Kenolube (Somaloy 500), although at the expense of a better maximum permeability (850 vs. 500) and higher hysteresis losses [1]-[2]. Fig. 1 compares the B-H curves of M-19, and the SMC materials Somaloy 500 and Somaloy1000. An approximate value of the resistivity is 75 μΏm, which is equivalent to 0.16 μΏm for electrical steel. Due to their magnetic isotropy, higher transverse rupture strength (140 MPa vs. 50 MPa) and higher resistivity, SMC is amenable to construct electrical machines with 3-dimensional magnetic field paths, resulting increased design flexibility and hence increased specific output [2], [4]. Prototyping blanks of the soft magnetic composite material and experimental setup is shown in fig. 1.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</p> <p><strong>Conclusion and discussion:</strong> The prototype although crude provided a stable output on a full operating range, even though the problems of large magnetizing current and inferior magnetizing curve with lower µr value of 850. The dynamic performances are completely dependent on the nature of the stator core and losses of the machine. The initial current drawn by the SMC machine is higher owing to the requirement of higher level of magnetization energy in bulk material than in laminates for a cycle of the source frequency. The comparative analysis of measured temperature rise values of the SMC prototype machine and thermal FEA simulation results indicated that the SMC machine temperature rise is lesser than conventional machine. Also this may lead to more efficient electromagnetic coupling and more efficient heat transfers ability and cooling capability. The comparison of measured vibration frequencies of the SMC prototype machine and FEA results of natural mode shape frequencies of stator and rotor showed reduced tendency for vibration of SMC machine. This is due to the cushioning nature of the insulation binder which has a very good viscous-elasticity property. Moreover iron powder cores present a higher damping factor in the radial and circumferential directions headed to a cut in the radiation of noise. Hitherto SMC material find application in complex geometry machines such as Claw pole and Transverse flux machines. Perusal of research literature indicates that none attempted to make use of SMC material in the fabrication of Switched Reluctance Machine (SRM) as SRM is a simple geometry machine. The inherent vibration and noise problems in SRM are addressed by various means as can be seen from published literature. The innovation lies in its maiden attempt to use SMC material to address vibration and noise issues. Owing to limitations of indigenous technology where this work has been carried out the results out of crude prototype may not be perfect but it insinuated the application possibility of SMC material in SRM to mitigate the noise and vibration issues. If the research can be continued with further funding and use of SMC powder material instead of pre-fabricated SMC blanks in the fabrication will result in more accurate results owing to perfection in the machine geometry.</p> <p><strong>&nbsp;</strong></p> <p>&nbsp;</p> vijayakumar, J. Mohanambigai, G. premsunder, P. saravanan Copyright (c) 2021 vijayakumar, J. Mohanambigai, G. premsunder, P. saravanan https://spast.org/techrep/article/view/2732 Thu, 21 Oct 2021 00:00:00 +0000 Experimental Investigation on Production and Strength of Self- Compacting Geo-Polymer Concrete https://spast.org/techrep/article/view/1743 <p>The economic strength of a country is reflected by the growth rate of infrastructure and highlighted by production rate of concrete. Concrete is majorly used product in construction industry from many years. It has been widely used due to the availability of raw materials for manufacture of cement, low relative cost, its versatility and adaptability to various structural shapes. However massive production of concrete and the associated manufacture of cement have negative impact on environment. The production of cement not only depletes significant amount of natural resources, but also liberates a considerable amount of carbon dioxide (CO<sub>2</sub>) and other greenhouse gases into the atmosphere as a result of de-carbonation of limestone and the combustion of fossil fuels. In addition, cement is among the most energy intensive construction materials next to aluminium and steel. It is also estimated that the world wide cement industry contributes around 1.65 billion tons of the greenhouse gas emissions annually. High consumption of natural resources, environmental concern$$of CO<sub>2</sub> emission due to cement production$$$and improvement on concreteperformance has become a driving force behind the search for alternative materials.</p> <p>Geopolymer Technology is one of the efforts in this regard. Now a day’s geopolymer technology has become a promising technology that provides a mature and cost effective solution to many problems. Geopolymer technology improves both environmental and engineering performance of concrete compared to traditional technologies. Also, materials used to produce geopolymer concrete are environmentally friendly and requires moderate energy to produce.</p> <p>All concretes essentially relay on being fully compacted to attain its designed strength. In large and complicated structures it is difficult to ensure full compaction, despite the good mix design. One of the solutions to overcome this difficulty is the employment of self-compacting concrete.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; By knowing the geopolymer technology and keeping in view the increasing trend towards SCC, an innovative type of concrete that can achieve the combined advantages of both the concretes is attempted in this study. Self-compacting geo polymer concrete is relatively a new concept and can be regarded as the most revolutionary development in the field of concrete technology. Self-compacting geo-polymer is an innovative type of concrete that does not require vibration for placing it and can be produced by complete elimination of Ordinary Portland cement[2].</p> <p>In this research an attempt has been made study on mix design and mechanical properties of Self compacting Geo-Polymer concrete. Fly-Ash, suitable coarse aggregate, fine aggregate, sodium hydroxide, sodium silicate, super-plasticizer and extra water has been used in producing self-compacting geo-polymer concrete. A suitable mix design accounting for M40 grade of concrete as per B V Rangan method [1] has been adopted and by trial and error methods optimum mix design values are evaluated and same is used for further study. Mechanical properties such as compressive strength split tensile strength and flexural strength of self-compacting geo-polymer concrete is studied by casting cubes, cylinder and prisms. The results are found satisfactory according to EN codes. Hence it is recommended to use self-compacting geopolymer concrete in place conventional concrete as it provides various benefits over it.</p> LAXMIPUTRA S WALI, Mourougane R, Shridevi Chikkur Copyright (c) 2021 LAXMIPUTRA S WALI, Mourougane R, Shridevi Chikkur https://spast.org/techrep/article/view/1743 Sat, 09 Oct 2021 00:00:00 +0000 Structural Characteristics of Agricultural Waste Incorporated as Replacements in Concrete – A Comparative Analysis https://spast.org/techrep/article/view/2866 <p>The construction industry is one of the major contributors to environmental pollution starting from the production of raw ingredients to recycling, demolition, and reconstruction. These are so far addressed by the addition of mineral admixes with pozzolanic properties leading to the inception of pozzolanic reactions during the processing of the concrete. The admixes include industrial by-products viz. fly ash, quarry dust, marble dust, and many more. Recent advancements in this direction also include the incorporation of by-products of plastic waste and the agricultural industry as well. Coconut and palm shells are one of these which are reported in various studies and concrete properties are investigated. In India recently there has been great concern raised towards atmospheric pollution and the culprit is the burning of leftover straw in the rice cultivation process leading to an increase in particulate matter in the atmosphere and consequently decreasing the quality of breathing air. The incorporation of rice husk, rice straw ash, and fiber in concrete production has been explored to some extent to address the effect of agricultural waste and by-products on the properties of concrete. The current paper elucidates a thorough investigation of the use of agricultural by-products as admixes in concrete production with specific attention to paddy straw in comparison with various other alternatives. Attention is also provided in the direction of the role of different parameters and microconstituents affecting the properties of concrete by incorporation of rice straw in the form of fibre and ash as well as different forms of alternative agricultural admixes. A comparative observation on the replacement of rice straw in concrete with other agricultural admixes has also been illustrated in context to strength, microstructural, and cost-effectiveness.</p> Sunita Sarangi, Sairam V Copyright (c) 2021 Sunita Sarangi, Sairam V https://spast.org/techrep/article/view/2866 Tue, 19 Oct 2021 00:00:00 +0000 Green synthesis of RGO based nanoparticles and composites for photocatalytic applications: A review https://spast.org/techrep/article/view/2902 <p>Water treatment systems that are both sustainable and capable of increasing water quality have been extensively researched. Photocatalytic technology, in particular, has shown viable method for the degradation of dangerous organic contaminants in contaminated water.&nbsp; And significant promise in recent years as a low-cost, ecologically beneficial, and long-term solution[1]. However, developing an optimal photocatalyst interms of physicochemical and optical properties that has high photocatalytic activity, excellent adsorption of pollutants from aqueous solutions, &nbsp;a large specific surface area, solar light harvesting tendencies, high photocharge separation efficiency, excellent stability and is recyclable is a major issue in the industrial development of photocatalyst technology. As a result, RGO and based composites may exhibit higher photocatalytic activity for photodegradation of a wide spectrum of organic contaminants [2]. The importance of green synthesis of RGO based nanoparticles and composites within the last decade has been increased and their environmental remediation is a significant reason to cater novel synthesis routes. As a result, green chemistry propositions, waste avoidance, energy efficacy, cleaner solvents and benign precursor materials have become critical factors in the synthesis process of these materials, spawning susbstantial research in this area. This review paper ”Green synthesis of rgo based nanoparticles and composites for photocatalytic application” diclosed all conceivable greener methods for the synthesis and properties of RGO based nanoparticles and nanocomposites Various plant sources, microbes and bicompaticle green reagents were used for the synthesis of rgo based nanopaticles and composites reported in the last decade are compiled. Although promising results have been reported, significant research void have been diagnosed, as well as their recyclability and applications in photocatalytic degradation of organic pollutants In this paper, the advantages of RGO based nanocomposites in a variety of environmental applications are thoroughly examined[3].</p> Puneetha J, Nagaraju Kottam, Rathna A Copyright (c) 2021 Puneetha J, Nagaraju Kottam, Rathna A https://spast.org/techrep/article/view/2902 Thu, 21 Oct 2021 00:00:00 +0000 Study of quantum capacitance of pure and functionalized Nb2C and Ti2C MXenes for supercapacitor applications https://spast.org/techrep/article/view/1347 <p><strong>Abstract </strong>&nbsp;</p> <p>The need of high capacity energy storage systems is increasing day by day with the rising energy demand for vehicles, electronic and communication devices. For centuries the batteries are used as energy storage devices. But due their limited life cycles, poor performance and environmental hazards, it has become utmost important to find energy storage devices that fulfil the energy requirements yet environment friendly. Supercapacitors (SC) are one of such energy storage devices. With advancements in the electrode materials of SC [1], they have become a viable and sustainable. But still SCs lag behind batteries in their energy density. Increase in their energy density can be achieved by increasing the capacitance of SC electrodes. Therefore scientists are in search of suitable new electrode materials with high capacitance values. One of the materials that have potential use as electrode are MXenes [2-5]. These are novel 2D materials with formula M<sub>m+1</sub>X<sub>m</sub> (m = 1, 2 or 3), where “M” is any transition metal “X” is N or/and C [6]. Their high specific surface area make them suitable candidate for supercapacitor electrodes. The capacitance of SC electrode material is strongly affected by its quantum capacitance that is the inherent property of the material used [7-8]. The equivalent capacitance C of the SC is actually a series combination of the double layer capacitance (Cd) and QC as below.</p> <p>The large QC values of materials for electrode are thus highly desirable. So, the computation of QC for a given material is necessary to explore its potential for supercapacitor applications. In present work, density of states, band structure and quantum capacitance of bare and functionalized niobium carbide and titanium carbide MXenes are studied using DFT. The calculations are performed using methodology as reported earlier by the authors [9-11]. Structures as given in fig.1 are designed using Synopsys ATK package’s crystal builder. The exchange correlation energy is approximated using generalized gradient approximation (GGA). Plane-wave PW energy cut off was 540 eV, with k-point &nbsp;meshes 12 X 12 X 1. The Band structures for both MXenes show zero band gaps which establish their metallic nature. Both MXenes Nb<sub>2</sub>C and Ti<sub>2</sub>C show good quantum capacitance values of 324.1 and 246.2 µF/cm<sup>2 </sup>respectively at Fermi level as shown in fig. 2.</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p><img src="https://spast.org/public/site/images/bharti/fig1-2.jpg" alt="Fig 1 &amp; 2" width="1625" height="857"></p> <p>Out of pristine structures of these, Nb<sub>2</sub>C shows higher value for quantum capacitance in comparison to Ti<sub>2</sub>C for both positive as well as negative electrodes. These calculations are also performed for functionalized MXenes. The results suggest that functionalization has significant impact on quantum capacitance of Nb<sub>2</sub>C and Ti<sub>2</sub>C MXenes as reported by other authors [4,12]. The QC values of bare and functionalized MXenes are more than that of graphene [13] at Fermi level, thus indicating that these MXenes are suitable electrode materials that can be a better substitute than graphene for electrode material.</p> Bharti, Yogesh, Meenal, shatendra Copyright (c) 2021 Bharti, Yogesh, Meenal, shatendra https://spast.org/techrep/article/view/1347 Wed, 06 Oct 2021 00:00:00 +0000 Study of Structural, Optical and Morphological behaviour of Perovskite Materials (RAlO3, R=La, Sm, Gd) prepared by Solution Combustion https://spast.org/techrep/article/view/1395 <p>Lanthanide aluminum perovskite (La to Lu) is a promising material for optical, electronic and structural applications. Among these, we have successfully synthesized some representative materials of this family like Lanthanum aluminum oxide (LaAlO<sub>3</sub>-LAO), Samarium aluminum oxide (SmAlO<sub>3</sub>-SAO) and Gadolinium aluminum oxide (GdAlO<sub>3</sub>-GAO) from metal (La, Sm, Gd) nitrates and aluminum nitrates by the solution combustion process, combusted at 500±20 ⁰C in 15 mins with urea as a fuel [1]. The solution combustion is the propagation of self-sustained exothermic reactions and the possibility of synthesizing perovskite oxides is in fast heating rates, short time, formation of high-purity products and cost-effective compare to other conventional methods like solid-state method, hydrothermal and co-prepetition method [2]. The obtained lanthanum aluminates (RAlO<sub>3</sub>; R= La, Sm, Gd) were characterized by thermal analysis (TGA-DTA), powder X-ray diffraction (XRD), Fourier Transform infrared spectroscopy (FT-IR), UV- Vis analysis, transmission electron spectroscopy (TEM), field emission-scanning electron spectroscopy (FE-SEM) accompany with energy-dispersive X-ray spectroscopy (EDX) and surface area analysis (BET).</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; The crystalline temperature of the LAO, SAO and GAO are 865 ⁰C, 887 ⁰C and 892 ⁰C, which is confirmed by TGA-DTA analysis, respectively. This crystalline temperature is indicating the phase transition from the amorphous phase to the crystalline phase. The XRD pattern of LAO, SAO and GAO powder calcinated in air at 1100 ⁰C for 2 hours are shown in the figure 1. They are crystallized as a single phase with a well-pronounced perovskite crystal structure and comparable to that of the reported patterns [3]. The average crystallite size of the RAlO<sub>3</sub> are calculated from Debye Scherrer’s equation and their value are listed in the table 1. The FTIR spectra shows the strong and sharp vibrational bands from 650 cm<sup>-1</sup> to 660 cm<sup>-1</sup> in RAlO<sub>3</sub>, which can be ascribed to the R-O (R= La, Sm, Gd) bonding in the oxide [4]. The week bands are observed at 425 cm<sup>-1</sup> which are assigned to AlO<sub>6</sub> octahedra in RAlO<sub>3</sub> [3]. This corroborates the XRD and thermal analysis results that the combustion is complete and no considerable organic matter presented in the sample. The optical bandgap of the LAO, SAO and GAO were investigated from tau’s plot using UV-vis DRS spectra and obtained results are 4.94 eV, 4.62 eV and 4.50 eV respectively.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; The surface morphology of the RAlO<sub>3</sub> is verified by FE-SEM analysis. The FE-SEM image shows the presence of agglomeration with a relatively dense structure, small pores and irregular shapes. Additionally, the corresponding EDX spectra indicated the existence of proposed elements La, Al, and O in LAO, while Sm, Al and O in SAO and Gd, Al, O in GAO without any other impurity. The TEM images revealed that the average size particle of the LAO, SAO and GAO between ~80-120 nm and its average pore size between ~ 15-25nm. The particle has seen as the faceted polyhedral shape and also appeared to be aggregate. The TEM images, in which the distinct lattice fringes with an interplanar spacing of ~3.24 Å, ~ 3.04 Å and ~ 3.34 Å, corresponding to the crystal plane of LAO (110), SAO (112) and GAO (112) were observed. We have also done the BET analysis to find the surface area, pores diameter and volume. The detailed result will be discussed.</p> <p>&nbsp;</p> <table width="347"> <tbody> <tr> <td width="104"> <p><strong>RAlO<sub>3</sub></strong></p> </td> <td width="153"> <p><strong>Avg. Crystallite Size</strong></p> </td> <td width="90"> <p><strong>Band Gap</strong></p> </td> </tr> <tr> <td width="104"> <p>LaAlO<sub>3</sub></p> </td> <td width="153"> <p>28.5 nm</p> </td> <td width="90"> <p>4.94 eV</p> </td> </tr> <tr> <td width="104"> <p>SmAlO<sub>3</sub></p> </td> <td width="153"> <p>30 nm</p> </td> <td width="90"> <p>4.62 eV</p> </td> </tr> <tr> <td width="104"> <p>GdAlO<sub>3</sub></p> </td> <td width="153"> <p>36 nm</p> </td> <td width="90"> <p>4.50 eV</p> </td> </tr> </tbody> </table> <p><strong>Table 1:</strong> Average crystallite size and bandgap of the RAlO3</p> <p>&nbsp;</p> VINOTH V, Madeswaran S, Murali R Copyright (c) 2021 VINOTH V, Madeswaran S, Murali R https://spast.org/techrep/article/view/1395 Fri, 01 Oct 2021 00:00:00 +0000 Effect of preparation techniques and nanoparticles content on the morphological and mechanical properties of polylactic acid nanocomposites https://spast.org/techrep/article/view/2090 <p>The formation of the micro-voids is the most common manufacturing defect observed in various casting processes due to the presence of air in the polymer matrix, which deteriorates prepared nanocomposite’s mechanical properties [1-2]. The authors suggested a new preparation technique to minimize the formation of micro-voids in PLA nanocomposites. The nanocomposites preparation by new technique involved melt mixing assisted with ultrasonic vibration and casting under the vacuum chamber. The nanocomposite samples were also prepared by the conventional compression moulding and solvent casting techniques, to analyse the effect of processing techniques on the properties of PLA. Calcium phosphate (CaP) and Magnesium phosphate (MgP) nanoparticles were incorporated with different wt% to study the effect of nanoparticles on the properties of the PLA. The reason behind selecting PLA for the study in the present work is its predominant use in various biomedical and packaging industries for new items [3-4]. The scanning electron microscope (SEM) was used to study the morphological property of the PLA nanocomposites. The result shows that several microvoids were found on the surface of the nanocomposites only in the melt mixed and compression-moulded sample and were absent in ultrasonic assisted melt mixing and vacuum casting, and solvent casting methods. The nanoparticles start agglomeration even at lower nanofiller concentration in the case of compression-moulded samples. The tensile strength of the PLA nanocomposites increases up to 15 wt% CaP and 2 wt% MgP nanoparticles content. In compression-moulded samples, the tensile strength is not likely to be enhanced at lower filler content, due to void formation. Based on the results, ultrasonic assisted melt mixing and vacuum casting technique is found as the best technique.</p> Govind Sahu Copyright (c) 2021 Govind Sahu https://spast.org/techrep/article/view/2090 Fri, 08 Oct 2021 00:00:00 +0000 A Rapid Synthesis Of SiO2 Nanoparticles For Fabrication Of Rewritable Superhydrophobic Surface Coatings https://spast.org/techrep/article/view/2124 <p>Superhydrophobic surfaces are being widely analysed, engineered, and employed for a variety of engineering applications ever since last decade because of some exceptional self-cleaning characteristics and anti-wetting behaviour. Herein we state the fabrication of poly vinyl alcohol (PVA) based rewritable superhydrophobic surface coating, through synthesized SiO<sub>2</sub> nanoparticles obtained using Sol-Gel technique. Liquid sodium silicate solution being utilized as precursor for the reaction. Surface functionalization of obtained SiO<sub>2</sub> nanoparticles is accomplished through trimethylchlorosilane (TMCS) treatment at ambient temperature. Surface functionalized SiO<sub>2</sub> nanoparticles were added and mixed at 03 wt.% into stock solution of PVA at 70 ⁰c. Solution was coated with spray gun over glass and metallic surfaces uniformly. A prominent contact angle was attained between surfaces and water droplet that averaged about 154º for metallic surface, and 151º for glass surfaces.</p> Abdul Khalique, Dr. M. Wasim Akhtar, Aqsa Shaikh, Muddassir Ali Memon Copyright (c) 2021 Abdul Khalique, Dr. M. Wasim Akhtar, Aqsa Shaikh, Muddassir Ali Memon https://spast.org/techrep/article/view/2124 Fri, 08 Oct 2021 00:00:00 +0000 Analysis of Foundation Using GEO 5 Software https://spast.org/techrep/article/view/1663 <p>The foundation of a structure is the component that connects it to the ground and transfers load from the structure to the earth. Foundations are classified as shallow and deep. In this analysis, Shallow foundation is considered. The analysis is to estimate and calculate the factor of safety using GEO5 student version Software. GEO5 Software is a geotechnical program that is used to construct and verify spread footing foundations using input parameters. A vertical and horizontal bearing capacity analysis is performed by the program. Design of Foundation includes four types of foundation. They are Centric Spread Footing, Eccentric Spread Footing, Circular Spread Footing, Strip Footing. Analysis of foundation include different cases like with and without earthquake, with and without surcharge. Main objective of analysis is to design and calculate the dimensions and stability of spread footing foundation and to find the value of factor of safety using GEO5 program. The present analysis looks into how four different types of foundations might increase their bearing capability. In comparison to other types of footing, the results demonstrate that bearing capacity increases greatly in the circular spread footing and decreases in the strip footing.</p> NAYAN M R Copyright (c) 2021 NAYAN M R https://spast.org/techrep/article/view/1663 Fri, 08 Oct 2021 00:00:00 +0000 Tuning of Morphological, Crystallographic and Optoelectronic Properties in Electrodeposition of CuSCN for Device Applications https://spast.org/techrep/article/view/693 <p>Copper(I) thiocyanate (CuSCN) is known as a wide bandgap p-type semiconductor and recently demonstrated its high ability as a hole-transporting material in solar cells and light emitting diodes. Its thin film is usually fabricated by simple solution coating and drying [1]. In fact, little is known for physical properties of CuSCN, such as bandgap, band positions, optical transparency, carrier density and mobility.<br>We have established methods to electrodeposit well-crystallized CuSCN thin films in various forms. Although the electrochemistry is fairly simple as limited by diffusion of 1 : 1 complex between Cu<sup>2+</sup> and SCN<sup>-</sup> ions ([Cu(SCN)]<sup>+</sup>), the [Cu<sup>2+</sup>] : [SCN<sup>-</sup>] ratio, its absolute concentration and solvent can significantly alter the morphology and crystal orientation of resulting CuSCN [2].<br>Hybridization with various cationic organic dyes has also been achieved to furnish nanostructures and even promote transition from rhombohedral β to orthorhombic α form [3]. These unique features of the electrodeposition technique let us anticipate possibilities to tailor-tune physical properties of CuSCN to match the demands for device applications. Moreover, electrodeposited CuSCN doesn’t hinder its use in flexible electronics unlike many other inorganic materials, since the process is done at room temperature.<br>In this study, we have carried out electrodeposition of CuSCN to vary its morphology and crystal orientation by tuning the bath composition and studied their band structure to explore the room for tuning its physical properties for diodes and hybrid electroluminescence devices. <br>Morphologies of CuSCN thin films electrodeposited from stoichiometric (REF), Cu-rich and SCN-rich baths are shown in Figs. 1 a-c. While the REF sample has an open structure made of relatively large bulky particles, the Cu-rich sample is dense, made of tiny grains to expose their hexagonally shaped top. XRD patterns have found almost random crystal orientation for the former and a high degree of preference of the latter to orient the c-axis of β-CuSCN perpendicular to the substrate. On the other hand, the one from the SCN-rich bath show rectangular sides of the grains (Fig. 1 a) and strongly oriented to lay down the c-axis in parallel with the substrate.<br>The Cu-rich film is highly transparent, whereas the others are opaque due to light scattering. Although all these films indicate nearly the same energy gap of about 3.6 eV estimated by Tauc plot, significant difference was found for their work function (WF) measured by photoelectron yield spectroscopy (PYS) (Fig. 2). The threshold energy moved downwards from 5.23 to 5.66 eV vs. VAC from Cu-rich to SCN-rich film. The result indicates a high level of p-type doping in the presence of excess SCN-, probably due to increased concentration of Cu2+ as stabilized by SCN- bound to it.<br>Simple devices as ITO/ electrodeposited CuSCN / Aluminium were fabricated to examine their diode behaviour. While all of the devices employing the electrodeposited CuSCN thin films showed good rectifications of the J-V curves, the onset voltage at 5 mA/cm<sup>2</sup> current moved from 1.21 to 2.57 V (ITO being positive) from Cu-rich to SCN-rich samples to confirm tunability of the device property by conditions of electrodeposition. Successful operation of organic light emitting diode was also achieved by employing the electrodeposited CuSCN as a hole-injection layer. Combination of photoelectron spectroscopies (XPS, UPS and IPES) is under way to examine the change of the band structure of CuSCN.</p> Kyota Uda, Yuki Tsuda, Tensyo Nakamura, Lina Sun, Yoshiyuki Suzuri, Takehiko Nagai, Tsukasa Yoshida Copyright (c) 2021 Kyota Uda, Yuki Tsuda, Tensyo Nakamura, Lina Sun, Yoshiyuki Suzuri, Takehiko Nagai, Tsukasa Yoshida https://spast.org/techrep/article/view/693 Mon, 20 Sep 2021 00:00:00 +0000 Magnetization graded magnetoelectric composites synthesized by electro-deposition https://spast.org/techrep/article/view/2402 <p>Multiferroic magnetoelectric (ME) composites are prepared by combining ferromagnetic (FM) and ferroelectric (FE) materials [1]. These ME composites have been attracting significant scientific interest due to their technological applications in magnetic field sensors and high frequency devices such as resonators and filters [2-8]. They exhibit a direct magnetoelectric effect via strain mediated coupling between the FM and FE materials. This results in generation of electrical response in the ferroelectric phase on subjecting the composite to a magnetic field. A converse magnetoelectric effect is observed when magnetic response in the FM phase is generated on application of electric field to the composite. The interaction between the two phases is called magentoelectric coupling which determines the extent of the ME effect [1-2]. Some single phase materials such as BiFeO<sub>3</sub> also exhibit weak ME effect at room temperature. The reason for the absence of single phase materials with strong ME coupling at room temperature in single phase materials is non- existence or scarcity of the presence of both FE and FM orders simultaneously [3]. On the other hand, ME composites do not have such issues. The choice of FE and FM materials and the way they are combined decide the strength of ME coupling. Generally, a ferromagnetic material having large magnetostrictive coefficient and a ferroelectric material with large piezoelectric coefficient are the desired choices if fabrication or synthesis processes are not complex or complicated. A number of FM materials, ferromagnetic metals such as Fe, Co, Ni, spinel ferrites e.g. CoFe<sub>2</sub>O<sub>4</sub>, NiFe<sub>2</sub>O<sub>4</sub>, garnets and also some alloys such as Permendur, Terfenol-D can be employed in ME composites. Likewise, FE materials, such as BaTiO<sub>3</sub>, PZT, PMN-PT are good choice for ME composites [5].</p> <p>ME composites can be formed in various phase connectivity schemes such as 0-3 type particulate composites [1, 9-10], 1-3 type, nano pillars of one phase in matrix of other phase [11] and 2-2 type laminate composites [12]. Among these, 2-2 type laminate composites are found to have much stronger ME coupling. In the last few years, a variety of layered ME composites have been investigated. Laletin <em>et</em> <em>al.</em> reported on the ME interactions in layered transition metal/PZT samples synthesized by bonding platelets of PZT and Fe, Co or Ni [12]. The 2-2 type laminate composites consist of magnetic and piezoelectric layers bonded together by epoxy adhesives. But use of adhesive epoxy to bond magnetic and piezoelectric layers influences the magnetoelectric coupling due to its possible fatigue effect and thereby weakens the ME effect. In order to eliminate the superfluous epoxy binders, electro-deposition [13] or magnetron sputtering [14] techniques have been employed to deposit the magnetic layers directly onto the piezoelectric material. Using electro-deposition of Ni, Pan <em>et al.</em> synthesized Ni–PZT–Ni tri-layered composites with a cylindrical form and obtained a maximum ME coefficient of 350 mV/cm Oe at 160 Oe and 1 kHz of H<sub>ac</sub> [13].</p> <p>In our work, we have studied low frequency ME effects in composites of PZT and functionally graded ferromagnetic layer of Ni and Co. Nickel and cobalt were electrodeposited on PZT (APC-851, American Piezo Ceramics) to prepare graded magnetization magnetoelectric composites of PZT-Ni-Co and PZT-Co-Ni. The effect of varying thickness fraction of Ni and Co on ME voltage coefficient was studied. Magnetic force microscopy (MFM) was used to observe the domain patterns in electrodeposited cobalt and nickel.&nbsp; Magnetostriction measurements of PZT-Ni and PZT-Co samples were carried out using a strain indicator. Fig. 1(a) shows the variation of in magnetolectric voltage coefficient (MEVC) with deposition time fractions of Co and Ni. Fig. 1(b) and (c) show the variation in ME coercivity and remanence with increase in deposit time and eventually thickness of Co layer.</p> <p>These ME composites may be useful in harvesting energy from omnipresent stray magnetic field and vibrations.</p> <p><sub>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </sub></p> <p><strong>Fig.1</strong><strong>.</strong> (a) MEVC vs Deposition time fraction of Ni and Co (b) Variation in coercivity with cobalt deposition time fraction (c) Variation in remanence with cobalt deposition time fraction</p> Tarun Garg, Gollapudi Sreenivasulu, G. Srinivasan Copyright (c) 2021 Tarun Garg, Gollapudi Sreenivasulu, G. Srinivasan https://spast.org/techrep/article/view/2402 Sun, 17 Oct 2021 00:00:00 +0000 Study on the Behavior of Axially Loaded Coconut Shell Concrete Column Using M-Sand in its Place of R-Sand https://spast.org/techrep/article/view/118 <div class="page" title="Page 1"> <div class="layoutArea"> <div class="column"> <p>In Current Construction Industry many developments are happening towards green concept, where the waste materials are reused to avoid the accumulation of Waste and reducing the conception or destroying the environment. In Line with the same green concept this study is done such that Manufacture Sand called as M Sand has been used as the replacement for Fine Aggregate. Coconut Shell has been used as replacement for Coarse Aggregate. The Replacement of M Sand as Fine Aggregate has helped in reducing the exploitation of riverbeds. Manufactured Sand are produced by crushing the rocks that are obtained from hills and mountains. The Coconut shell has been used as the aggregates for producing lightweight concrete. As the Coconut shell has the properties of storing water this helps in internal curing of the Concrete. In this research have done the analysis of short column and long column with normal concrete and coconut shell concrete using M-sand in its place of R-sand. 12 Columns with different reinforcements have casted and tested. 6 columns for Short Columns and 6 for long columns. In the short columns both normal concrete and coconut shell concrete are casted with 3 different types of reinforcements. The same different types of reinforcements are done for long column too. These columns are casted and cured using gunny bags for 28 days.</p> </div> </div> </div> ramasubramani r Copyright (c) 2021 ramasubramani r https://spast.org/techrep/article/view/118 Mon, 23 Aug 2021 00:00:00 +0000 The Compressive Strength of Brick Masonry Confined with Glass Fibre Reinforced Polymer https://spast.org/techrep/article/view/2552 <p>Compressive strength is one of the basic properties influencing behavior of brick masonry. Various traditional techniques are used to strengthen unreinforced brick masonry. However, addition of considerable mass and thickness to the original structure affects both aesthetics and economy. Improvement in shear and flexural strength of unreinforced masonry walls confined with GFRP multi layered tendons or strips have been reported by many researchers [1-3]. Significant enhancement in compressive strength and deformability has been reported for short masonry columns wrapped with 5 layered GFRP strips as jacket [3]. Hence, in this study, behaviour of brick masonry prisms confined with single layer glass fibre reinforced polymer (GFRP) is investigated. English bonded prisms have been constructed with various patterns of wrapping techniques using fibre and resins. Basic tests on constituent materials have been conducted as per standard code of specifications.</p> <p>The test results indicated enhancement in the compressive strength of prisms wrapped with single layer of glass fibre by 15% to 36%. Also, Prism compressive strength of epoxy resin based wrapping has been 1.14 times and 1.37 times higher as compared to polyester resin based wrapping and control specimens respectively. Strain capacity of GFRP confined brick masonry prism has increased by 2 – 3 times as compared to unconfined prisms. It is interesting to note that application of Epoxy coat enhances the compressive strength and strain capacity of a specimen, but increases the cost of construction by 48% as that of coating with polyester.</p> <p>&nbsp;</p> Somanath M Basutkar Copyright (c) 2021 Somanath M Basutkar https://spast.org/techrep/article/view/2552 Sun, 17 Oct 2021 00:00:00 +0000 A Highly uniform resistive switching achieved in Pt/SrTiO3/Pt memristive devices through engineering bottom interface https://spast.org/techrep/article/view/241 <p>SrTiO<sub>3</sub> (STO) is a model switching material for valence change memristive cells; there exists general consensus that the resistive switching can be attributed to the migration of oxygen vacancies between metal electrodes and STO. However, most of STO-based devices are fabricated on Nb-doped STO substrates, which is not compatible with the current CMOS technology. Herein, by using pulsed laser deposition (PLD) technique and engineering the bottom interface through pre-annealing of the Pt electrode in O<sub>2</sub> atmosphere, high-quality single-crystal STO films are successfully deposited on Si wafers. Moreover, destructive electroforming process is avoided, which results in volatile analog resistive switching behavior with device yield &gt; 98%. Moreover, tunable synaptic functions, such as the short-term plasticity and the paired-pulse facilitation, are achieved in the devices.</p> Jamal Shaibo Copyright (c) 2021 Jamal Shaibo https://spast.org/techrep/article/view/241 Sat, 11 Sep 2021 00:00:00 +0000 An Overview on Smart Polymers as the Backbone to Hard Tissue Formation https://spast.org/techrep/article/view/2142 <p>Bone and tooth (dentin, enamel, and cementum) are living, mineralized tissues with a high degree of hardness. After a fracture or defect, bones have a moderate capacity to self-heal, however osteoporosis can increase the risk of bone fractures owing to population ageing. Dental caries is another common human illness .secondary caries causes caries therapy to fail over time. Hard tissue regeneration comes at a high cost to society, which is likely to rise substantially as the population ages.As a result, developing appropriate biomaterials for hard tissue repair and regeneration is a critical job, particularly in countries with a significant senior population.</p> <p>Smart materials, also known as responsive materials, are synthetic materials that can have one or more characteristics that can be modified by external stimuli. Polymeric smart materials are most often utilised in the biomedical area because they combine natural polymers' high biocompatibility with synthetic polymers' adjustable and functional characteristics. Temperature, redox reactions, humidity, electric or magnetic fields, pH variations, and light intensity are only a few sources of potential stimuli for smart materials .Biosensors, controlled drug delivery, tissue repairing, local injection, cancer cell separators, minimally invasive surgery, and 3D bioprinting, among other biomedical uses, have all employed materials with distinct triggering mechanisms. Smart polymeric materials' adjustable characteristics and environmental reactions enable the creation of customised biomedical products. This review will focus on the use of smart polymers in the regeneration of hard tissue.</p> <p>Despite significant advancements in microsurgical methods over the last few decades, bone tissue remains a difficult area to restore functionally and structurally after injury. Tissue engineering techniques address an urgent clinical demand for therapeutic alternatives to bone autografts by creating substitute materials that match the physical and biological characteristics of healthy tissue. Polymers play a key role in the creation of biodegradable matrices that hold cells in place and support the development of new tissue until they are integrated into the transplanted region due to their structural flexibility (i.e., scaffolds).An external stimulus, such as temperature change, an electric or magnetic field, or light, can cause shape-memory polymers (SMPs) to revert to their original shape. Because of their uses in tissue engineering, they've gotten a lot of attention. The shape memory behaviour of the scaffolds allows them to be predesigned, distorted for easy insertion into bone defects via minimally invasive surgery, and then extended to conform to an uneven bone defect. The first implant is modest in size and may be implanted in the body utilising minimally invasive techniques that cause the least amount of harm to the host tissues. The implant takes on a bigger shape once it is implanted.</p> <p>Nanostructured biopolymers, such as scaffolds, hydrogels, nanofibers, dendrimers, films and nanostructured bioceramics, such as hydroxyapatite, bioactive glass ceramic/bioglass, etc., in the form of nanoparticles, nanocrystals, nanorods, paste, and so on, are being used to regenerate both hard and soft tissues of the human body at the same time. These various forms closely resemble the natural components and structure of dental tissues, particularly enamel, dentin, and periodontium, in the dental area.</p> <p>The technique of remineralization of dentin lesions using polymer-induced liquid precursors has now been used. A partly demineralized human dentin (140 m deep artificial caries lesions) was remineralized for 7–28 days at 37 °C utilising the Polymer-induced liquid precursor’s method. With time, the degree of remineralization increased, and about half of the lesion depth was restored to normal elastic modulus values.</p> Siddique Sha Copyright (c) 2021 Siddique Sha https://spast.org/techrep/article/view/2142 Fri, 08 Oct 2021 00:00:00 +0000 A Carbon nanotubes: A Futuristic nanomaterial for Drug Delivery and Biomedical Applications https://spast.org/techrep/article/view/1181 <p>Nanotechnology has been evolved to be feasible and elegant in various fields particularly in biomedical domain. A carbon nanotube is one of the most eminent nanomaterials used in diverse applications of nanotechnology. Carbon nanotubes (CNTs) are rolled up sheet of graphene with chemical bonding of sp<sup>2 </sup>hybridized bonds. CNTs have remarkable properties such as magnificent strength and higher surface area, which makes it more attractive for employment in drug delivery system. CNTs could be used to deliver drugs with great accuracy and reduced adverse consequences. In this view, many scientific studies in drug delivery system demonstrated with the utilization of either single-walled carbon nanotube (SWCNT) or multi-walled carbon nanotube (MWCNT) for controlled release of drugs and showed optimistic characteristics in specific targeted delivery. However, carbon nanotubes toxicity level, agglomeration and deposition of CNTs in tissues are the main limitations to be examined consciously. The revelation of biosafety aspects of carbon nanotubes to human is still apprehensive. Hence, more investigations are needed to overcome the challenges associated with carbon nanotubes to effectively accomplish in developing nano based novel drugs formulation. The aim of this review is to discuss about the significant features and outcomes of carbon nanotubes in drug delivery for various therapeutic applications. The synthesis techniques and desire attribute of carbon nanotubes in pharmacological effect are also reviewed. The toxic level of carbon nanotubes and their role in biomedical activities are highlighted. The limitations, safety aspects, challenges and scope for future research are also projected in the article. &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</p> Ponnusamy Palanisamy, Venkataramanan Srinivasan Copyright (c) 2021 Ponnusamy Palanisamy, Venkataramanan Srinivasan https://spast.org/techrep/article/view/1181 Fri, 24 Sep 2021 00:00:00 +0000 MSELD SnSe thin films obtained on thermal annealing of Sn/Se stack for use in PV technologies https://spast.org/techrep/article/view/2258 <p>Recently, attention has been paid in search of new compound semiconducting materials which offer wide range of optical properties suitable for various applications as solar selective absorbers, thermoelectric devices, sensors in the field of photonic sciences. Among these, tin chalcogenides of SnE (where E = S, Se or Te) type found to exhibit considerable attention due to their excellent photonic characteristics in the form of high absorption across the EM spectrum ranging from NIR to UV region due to its property of having narrow bandgap. SnSe materials possess many advantages having direct bandgap of 1.0 to 1.3 eV close to the optimum value for solar photovoltaic conversion with absorption coefficient ~10<sup>5</sup> cm<sup>-1</sup> near fundamental absorption edge. Thus, demonstrate complete absorption of solar radiation from this fundamental absorption edge to Vis. and NIR region. The motivational aspect for undertaking such material is being relatively earth abundant, non-toxic and exhibit theoretical efficiency (SQ limit) of 32 %. Till date, the reported experimental efficiency of SnSe based solar cells ~1.4 %. Such low solar conversions in comparison to the SQ limit are attributed to the less exploration, presence of defect interface, trap states, secondary phases and unfavourable heterojunction band discontinuity.</p> <p>In the present work, Sn and Se constituents were used as a source material for deposition of thin films using multisource sequential element layer deposition (MSELD) technique. The obtained films were annealed at temperatures varying from 473 K to 673 K to transform the MSEL deposited layers into SnSe through interlayer diffusion of Sn and Se atoms. The technique is similar to selenization with a difference from present study is ‘Se’ being deposited in the form of layer without disturbing the vacuum, thus, presents controlled use of ‘Se’ content during the process.</p> <p>Sn/Se stack showed increased ‘Se’ concentration with increase in annealing temperature from 473 K to 673 K and exhibits enhanced reaction between the deposited constituents. Thus, the MSELD deposited films present increased insertion of ‘Se’ atoms in ‘Sn’ lattice on increasing the annealing temperature. The films showed a consistent increase in 'Se' content with the corresponding decrease in ‘Sn’ concentration. This increase in ‘Se’ concentration with increase in annealing temperature exhibits changes in their structural, optical, morphology and electrical characteristics of the films.</p> <p>The films annealed at 473 K found to possess dominant peaks of ‘Sn’ phase with the presence of minor peaks corresponding to SnSe phase. The emergences of these minor peaks corresponding to SnSe phase are attributed to the solid-state reaction of ‘Se’ atoms with ‘Sn’ lattice at the interface of the layers. Thus, the formation of SnSe phase attributed to the solid phase reaction kinematics of ‘Sn’ and ‘Se’ layer and allows interlayer diffusion at the interface.&nbsp; This SnSe presence has been confirmed through the peaks at 2θ values of 29.825<sup>0</sup> and 25.325<sup>0</sup> along (201) and (011) plane as per the JCPDS card no 48-1224. Optical measurements showed bandgap tuning from 1.24 eV to 1.78 eV with changed annealing temperature. Therefore, the work presents composition variation of the deposited films enabling bandgap tuning from NIR to visible region of the EM spectrum due to interlayer diffusion as a function of annealing. Thus, exhibit its application in the field of sensors whose fundamental absorption edge varied from visible to NIR region demonstrating absorption over wide range of solar spectrum for its use in various photonic applications. The films annealed at different temperatures exhibit p-type conductivity for its use as an absorber layer in the spectral selective solar absorbers. The films annealed at 473 K showed bulk resistivity of 3.41x10<sup>-3 </sup>Ωcm which increases with increased annealing temperature to 125 Ωcm for the films annealed at 673 K. such variation in electrical parameters are attributed to conversion of metal (Sn) into metal chalcogenide (SnSe) compound semiconductor.</p> <p>&nbsp;</p> <p>SnSe phase formation through ‘Se’ diffusion into ‘Sn’ layer has been achieved using facile MSELD technique on annealing with lower selenium loss in comparison to selenization technique. The films showed suitable electrical characteristics with the presence of different alloy phases due to interlayer diffusion of chalcogen anion (Se<sup>2-</sup>) in metal (Sn<sup>2+</sup>) forming metal chalcogenide (SnSe). Thus, the present investigations show transformations of ‘Sn’ lattice into SnSe on the basis of structural, optical, compositional, morphology and electrical results. A single SnSe phase has been achieved on annealing at 523 K using facile evaporation method for large scale production having suitable Eg value (1.24 eV), absorption coefficient (&gt; 10<sup>5</sup> cm<sup>-1</sup>), electrical resistivity and carrier concentration for its use as solar absorber. The films also exhibit tuning of solar spectrum from NIR to visible region due to compositional changes achieved on variation of annealing temperature. In summary, the films demonstrate its utility as solar selective absorbers and various other photonic applications by tuning its bandgap from NIR to visible region with high absorption and suitable electrical characteristics.</p> <p>&nbsp;</p> Arun Banotra, Naresh Padha Copyright (c) 2021 Arun Banotra, Naresh Padha https://spast.org/techrep/article/view/2258 Thu, 07 Oct 2021 00:00:00 +0000 Nanocoatings in the textile industry: Present and Future https://spast.org/techrep/article/view/1253 <p>The concept of textile coatings dates back to ancient times where waterproof fabrics were obtained by smearing animal fat onto their surface. Since then, a variety of materials are coated on textiles for different applications [1]. The objective of coating, in any case, is to either reinforce already existing properties of the given material or to introduce completely novel properties and hence producing a new finished product [2]. A coating is termed nanocoating if it is made of nanomaterials. A few nanomaterials used in textiles may include TiO<sub>2</sub>, SiO<sub>2</sub>, Fe<sub>2</sub>O<sub>3,</sub> and so on. The addition of nanomaterials leads to high opacity, increase in strength and durability. Nanocoatings also have many advantages over conventional coatings like increased indentation resistance, high elasticity, fast-drying, no shrinkage, high water vapor permeability, etc. Impregnation, cross-linking, and plasma surface activation are some of the methods through which nanomaterials can be incorporated into textiles. Also, the feasibility of such incorporation methods on an industrial scale plays an important role. The stage at which the nanomaterials are incorporated plays an important role in enhancing the properties of the fabric and also has an impact on its price [3]. Hydrophobic/water-repelling and stain-free fabrics are a few examples of textiles with nano-coatings. Nano-coatings also make fabrics antifungal and antibacterial. Few nanomaterials bring antimicrobial/antiviral properties to the fabrics and have gained importance due to the COVID-19 pandemic.</p> <p>The future of Nanocoatings in textiles is massive and very interesting. Few ideas include smart textiles which can be used in AI, robotics, medicine, and even in the dispersion of medicine onto the skin. Intelligent textiles are another class that allows textiles to act according to the surrounding environment. The temperature of the textiles changes according to the requirement to keep the person cool/warm.</p> <p>There is a need to evaluate the environmental impact of these special classes of fabrics during washing, handling and disposal as the nanomaterials may have adverse effects on the ecosystem when it gets into the soil and aquatic bodies [4].</p> <p>This paper provides an overview of the present status of nanotechnology in the textile industry and its future. Methods of incorporation of nanomaterials onto fabrics, stages at which the nanomaterials should be incorporated, the feasibility of the methods of incorporation on an industrial scale, economic evaluation, and smart textiles are some of the aspects discussed in this paper.</p> Ujwal Shreenag Meda, Shravan S Ranga, Samhita M Kiran Copyright (c) 2021 Ujwal Shreenag Meda, Shravan S Ranga, Samhita M Kiran https://spast.org/techrep/article/view/1253 Thu, 30 Sep 2021 00:00:00 +0000 Influence of GGBS and Alkaline Ratio on Compression Strength of Geopolymer Concrete https://spast.org/techrep/article/view/2900 <p>The cement production process tends to be a major source of greenhouse gas emissions in construction projects all over the world that rely on cement for concrete purposes in massive amounts. According to [1], during the cement manufacturing process, the same amount of carbon emission is released into the atmosphere for one ton of cement. This is due to the decarbonization of limestone in kilns during cement production and the combustion of fossil fuels. [2] During cement production, it emits 0.53 tons of carbon dioxide, and if the cement is produced using carbon fuel, a total of 0.98 tons of carbon dioxide is released into the atmosphere, resulting in global warming and emissions. Thus, in the construction project, replacing cement with geopolymer material reduces pollution in two ways: reduction of CO<sub>2</sub> emissions into the air by lowering cement consumption; and usage of fly ash, which is a by-product of thermal power plants. Industries that produce cement are responsible for removing waste and repurposing it as a viable alternative to cement [3]. The processing of fly ash contributes 80 to 90% fewer greenhouse gases into the atmosphere [4]. The materials used are mostly determined by variables such as cost, availability, and the type of application, among others. Geopolymer concrete employs sustainable construction materials as binders. The locally available industry by-products are used as a binder instead of cement. Due to its use of abundant wastes and low greenhouse gas emissions, GPC is both economical and eco-friendly [5]. This research aims to study the effects of source materials and different concentrations of NaOH on the strength characteristics of GPC. In fly ash-based geopolymers, alkaline activators cause the silica and alumina in the source material to form a gel to enhance bonding between aggregates with any unreacted components.[6] stated that geopolymer concrete requires thermal curing at 40-70 degrees Celsius to faster the hydration process, therefore the specimens are cured between 24 and 48 hours in the oven. [7] studied characteristics of geopolymer concrete with different replacements of GGBS to flyash and found the increase of GGBS content improved strength and decreased workability. This research examines the compressive strength of specimens for two different binders 360 and 400 kg/m<sup>3</sup> (replacing flyash with GGBS with 70-30, 60-40, and 50-50) with different A/B ratios (0.45 &amp; 0.5) in line with an alkaline solution made of NaOH and Na<sub>2</sub>Sio<sub>2</sub> and specimens were cured for 7 and 28 days (outdoor curing and oven curing at 60°C for 24 hours). Overall, 144 cubes were cast to determine compressive strength, in line with the workability of GPC. The findings have shown that GPC with appropriate strength may be produced by utilizing fly ash and GGBS combination in the outdoors, without the need for oven curing. However, there is less work conducted by various researchers on geopolymer concrete to determine mechanical properties with various replacements of GGBS and different molarities. This work would set a benchmark for future researchers in the field of geopolymer. It would provide a pathway for further studies of this material when a geopolymer concrete that was cured outdoors had a reasonable compressive strength.</p> KIRAN KUMAR POLOJU, Dr. K. Srinivasu Copyright (c) 2021 KIRAN KUMAR POLOJU, Dr. K. Srinivasu https://spast.org/techrep/article/view/2900 Thu, 21 Oct 2021 00:00:00 +0000 The effect of cell thickness for tuning electro-optical properties of ferroelectric liquid crystals for display applications https://spast.org/techrep/article/view/2494 <p><strong>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;The effect of cell thickness for tuning electro-optical properties of ferroelectric liquid crystals for display applications</strong></p> <p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;T K Abhilash<sup>1,2</sup>, Michał Czerwiński<sup>3</sup> and Achu Chandran<sup>1,2*</sup></p> <p><sup>&nbsp;&nbsp;</sup></p> <p><sup>1</sup>Materials Science and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (NIIST), Thiruvananthapuram-695019, India&nbsp; <sup>2</sup>Academy of Scientific and Innovative Research (AcSIR), Ghaziabad- 201002, India</p> <p><sup>3</sup>Faculty of Advanced Technologies and Chemistry, Military University of Technology, Warsaw, Poland</p> <p>&nbsp;</p> <p>Email ID: atkphysics@gmail.com, <a href="mailto:achuchandran@niist.res.in">achuchandran@niist.res.in</a></p> <p>&nbsp;</p> <p><strong>Abstract </strong></p> <p>Ferroelectric Liquid Crystals (FLC) are a special class of liquid crystals (LC) characterized by their unique properties such as high switching speed, low threshold voltage, high optical contrast, and memory effect [1]. LCs are widely used in display applications for more than four decades, but still needs improvement in electro-optical characteristics for use in next-generation advanced display applications. Also, the presence of ionic impurities degrades the performance of mesogens in display applications. The material parameters such as permittivity, spontaneous polarization, and switching time significantly impact the fabrication of improved and efficient LC display devices. The principal way to enhance material parameters is by changing the molecular structure of mesogens or introducing dopant materials. But LC cell thickness has a remarkable influence on tuning the electro-optical parameters and molecular relaxation processes due to the interaction of mesogens with the device surfaces [2]. This study investigates the effect of cell thickness in the electro-optical properties of FLCs with fluorinated chiral dopants. The FLC materials used in this study are pristine W301 and its fluorinated chiral derivatives, W453 and W457 [3]. The pristine sample W301 is an FLC mixture consisting of pyrimidine compounds and chiral terphenyl dopants[4]. In W453, the chiral dopant has an ester linkage group with two oppositely oriented fluorine atoms. In W457, an ethereal linkage is used as the linkage group in the chiral dopant with four fluorine atoms on the same side of the molecular core of the chiral dopant structure [3]. The samples are filled into LC cells with thicknesses 3.2 µm, 4.5 µm, 7 µm respectively, above the isotropic temperature through capillary action. Further the dielectric and electro-optical properties of the FLC samples are measured.</p> <p>&nbsp;</p> <p>The optical micrographs using a polarizing optical microscope in crossed polarized positions show that mesogens' alignment got affected with varying cell thickness. The variation of permittivity with different cell thicknesses is presented in Table 1. The decline in dielectric strength with a decrease in cell thickness is observed for W301 and W453 samples. The reduction in dielectric strength with a decrease in cell thickness indicates that the molecular motion responsible for the dielectric response in the thin cell is not free compared to thick cells [5]. A reverse trend in the permittivity value with the thickness is observed for the sample W457 characterized with an ethereal linkage group. It shows that the mesogenic structure and linkage group has a significant impact on tuning the permittivity along with the boundary conditions. The behaviour of dielectric permittivity can be explained at the expense of polarization using equation [5]–[7] (1)</p> <p><img src="https://spast.org/public/site/images/atkphysics/eq.jpg" alt="" width="152" height="49">………………………………………………..(1)</p> <p>Where K<sub>3</sub> is the twist elastic constant, q is the wave vector of the helix,&nbsp;is the tilt angle. It is clear from equation (1) that P<sub>s</sub> is proportional to the dielectric strength which in turn proportion to the magnitude of&nbsp; &nbsp;permittivity . The increase in the magnitude of permittivity is due to an increase in the value of P<sub>s</sub>. There is an increase in spontaneous polarization is observed for W457 with a decrease in thickness. The enhancement in polarization in turn tunes its permittivity according to equation (1).</p> <p><strong>Table 1</strong>. The variation of permittivity with cell thickness for the samples at room temperature.</p> <table> <tbody> <tr> <td rowspan="2" width="150"> <p>Name of the sample</p> </td> <td colspan="3" width="451"> <p>Value of Permittivity at 100 Hz (Room temperature)</p> </td> </tr> <tr> <td width="150"> <p>7</p> </td> <td width="150"> <p>4.5</p> </td> <td width="150"> <p>3.2</p> </td> </tr> <tr> <td width="150"> <p>W301</p> </td> <td width="150"> <p>35.53</p> <p>&nbsp;</p> </td> <td width="150"> <p>25.33</p> <p>&nbsp;</p> </td> <td width="150"> <p>16.5</p> <p>&nbsp;</p> </td> </tr> <tr> <td width="150"> <p>W453</p> </td> <td width="150"> <p>30.13</p> <p>&nbsp;</p> </td> <td width="150"> <p>20.54</p> <p>&nbsp;</p> </td> <td width="150"> <p>11.36</p> <p>&nbsp;</p> </td> </tr> <tr> <td width="150"> <p>W457</p> </td> <td width="150"> <p>5.88</p> <p>&nbsp;</p> </td> <td width="150"> <p>6.74</p> <p>&nbsp;</p> </td> <td width="150"> <p>7.07</p> <p>&nbsp;</p> </td> </tr> </tbody> </table> <p>&nbsp;</p> <p>The influence of cell thickness on the material parameters such as polarization, switching time, and rotational viscosity is shown in fig 1. The polarization of two samples W301 and W453, increased with increase in cell thickness, and it follows theoretical predictions [8], [9] while W457 shows the opposite trend. The surface anchoring energy and the cell gap influence the response time of the mesogens [10]. It is observed that the response time of the sample shows a significant decrease with a decrease in thickness of the cell. &nbsp;The response time of all the samples is consistent with the theoretical predictions. The rotational viscosity is derived from the experimental values of polarization and switching time. Hence the variation in rotational viscosity is contributed by the corresponding changes in polarization and switching time of the samples.</p> <p><img src="https://spast.org/public/site/images/atkphysics/electro-optic.png" alt="" width="1519" height="940"></p> <p><strong>Fig.1.</strong> Variation of polarization (a),(b),(c) ; switching time (d),(e),(f) ; rotational viscosity (g),(h),(i) with the applied field of FLC samples filled in LC cells with 7, 4.5 and 3.2 µm thick cells respectively at room temperature.</p> <p>This study provides an avenue for tailoring the dielectric and electro-optical properties of FLC materials with fine-tuning the chiral dopant structure along with LC cell thickness for device applications</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p><strong>&nbsp;</strong></p> Abhilash, Dr.Achu Chandran, Michał Czerwiński Copyright (c) 2021 Abhilash, Dr.Achu Chandran, Michał Czerwiński https://spast.org/techrep/article/view/2494 Fri, 15 Oct 2021 00:00:00 +0000 Ruthenium nanoparticle based recyclable heterogeneous catalyst for one-pot synthesis of benzoxazole derivatives in aqueous medium https://spast.org/techrep/article/view/1972 <p>Novel heterogeneous catalysts for benzoxazole synthesis using Ru and Fe metal centres were studied. The synthesized nanoparticles allowing their magnetic recovery, a complete characterization of nanoparticles based on the composition, morphology and structure related catalytic property by using powder Xray diffraction technique(XRD), Xray photoelectron spectroscopy(XPS), energy dispersive Xray spectroscopic technique (EDX) and scanning electron microscopy technique (SEM). The synthesized bimetallic nanoparticle(BNP) has been used as a heterogeneous catalyst for the organic transformation reaction between 2-aminophenol and different aldehydes to reap corresponding imines, which is followed by a catalytic cyclization from good to excellent yield. The catalyst was recovered magnetically and reused up to fifth catalytic cycle without substantial loss of catalytic activity.</p> Sachin Bhat Copyright (c) 2021 Sachin Bhat https://spast.org/techrep/article/view/1972 Sat, 09 Oct 2021 00:00:00 +0000 A Comprehensive Review on the Current Status of Virucidal / Bactericidal Surface Coating to Prevent Surface Contamination https://spast.org/techrep/article/view/1577 <p>COVID-19 is currently a global pandemic impacting over <strong>200 countries and territories</strong>&nbsp;around the world and has already claimed the lives of more than 4.7 million individuals worldwide with total confirmed cases of around 220 million. The causative virus, Coronaviruses (CoV) belong to a large family of viruses that are responsible to cause illnesses ranging from the common cold to more severe conditions [1]. A new strain, previously unidentified in humans, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is capable of human-to-human transmission has caused a health catastrophe of the decade, by infecting millions with COVID-19, globally and it was first identified in Wuhan, China, in December 2019, and was declared to be a Public Health Emergency of International Concern on 30 January 2020 and finally being announced as a pandemic by the World Health Organization on 11 March 2020.</p> <p>Understanding the different transmission routes of SARS-CoV-2 is crucial in planning effective interventions to break the chain of transmission. COVID-19 can be transmitted from an infected person through exhalation or emission of body fluids or aerosol particles containing the virus, which then attach to the surfaces and subsequently touched by receiver person. Therefore, viral contamination of the air and surfaces could have serious implications for outbreak control strategies. The ability of Corona viruses to sustain on various surfaces for a longer time has become a major reason for its fast spread apart from human-to-human transmissions [2]. This finding has created a general ‘surface phobia’, characterized by a fear of doorknobs, elevator buttons, handrails, switches etc. as hand contact with virus-contaminated surfaces is now regarded as one of the most common routes in promoting the transmission of COVID-19. In order to prevent the transmission of this virus through surface contamination, it is required to maintain their sterility, particularly in places with a high number of people, such as hospitals or clinics. Sterilization of such surfaces is although effective, but it does not serve to provide a permanent solution, therefore, a surface coating that not only kills but also avoids the attachment of virus particles is the need of the hour. Many biocidal surface coatings have already been reported to be either anti-microbial or anti-adhesives or they leach out nanoparticles and become incompetent overtime. In this aspect, development of coating materials which renders the virus activity as well as restricts its attachment will be ideal in controlling the hidden transmission of the virus. In the present review, we summarize several synthetic surface coatings with biocidal properties, including metals, polymers and superhydrophobic coating. We also mention the physico-chemical properties of surfaces that can influence virus/bacteria attachment on those surfaces. Biocidal activity based on ‘microbe-repelling’ and ‘release killing of biocide’ of the anti-adhesive biocidal coating with respect to SARS-CoV-2 will also be discussed in this review article. We specially emphasize on the dual functional biocidal surface coating materials comprising of metal nanoparticles embedded either in polymer or decorated in superhydrophobic matrix, their synthesis methodology, coating process as well as durability of the coatings.</p> <p>&nbsp;</p> Dr Sudeshna Ray, Dr. Prachi Tadge Copyright (c) 2021 Dr Sudeshna Ray, Dr. Prachi Tadge https://spast.org/techrep/article/view/1577 Fri, 08 Oct 2021 00:00:00 +0000 Influence of deposition conditions on properties of Ta2O5 films deposited by Ion Beam Sputtering Deposition Technique https://spast.org/techrep/article/view/2383 <p>Investigation of deposition conditions on structural, optical, and surface properties of Tantalum pentaoxide (Ta<sub>2</sub>O<sub>5</sub>) thin films deposited without assisted ion beam (Single Ion Beam Sputtering Technique, SIBS) and with assisted ion beam (Dual Ion Beam Sputtering technique, DIBS) is carried out. For both SIBS and DIBS identical coating process conditions are applied for deposition of Ta<sub>2</sub>O<sub>5</sub> films onto highly polished and clean, fused silica substrates. Estimation of deposition rates of Ta<sub>2</sub>O<sub>5</sub> with identical beam energies and coating chamber conditions is done. Benefits of O<sub>2</sub> assist beam on the behavior of structural, optical, and surface properties of thin films deposited are studied. The films are characterized with ellipsometer, optical profilometer, XRD, FE-SEM and XPS techniques to bring the merits films coated of Ion Beam Sputtering deposition with and without assist Ion Beam. Configuration of ion sources and targets in the coating chamber for dual ion beam sputtering of oxide targets is carried out in the present work are useful for multi-layer coatings for high reflectivity mirrors for electro-optical instruments like ring laser based rotation sensors.</p> laxminarayana gangalakurti, Professor, Dr. Copyright (c) 2021 laxminarayana gangalakurti, Professor, Dr. https://spast.org/techrep/article/view/2383 Sun, 10 Oct 2021 00:00:00 +0000 Internal friction studies of microwave sintered multiferroic BiFeO3 nanoparticles https://spast.org/techrep/article/view/1989 <p>Bismuth ferrite (BiFeO<sub>3</sub>) is a well-known multiferroic ceramic rigorously studied for its magnetic and ferroelectric properties at room temperature [1, 2]. Bismuth ferrite (BF) can be a replacement for lead-based ferroelectrics and piezoelectric components in electronic devices [3].&nbsp; Nanoparticles of bismuth ferrite are synthesized by Hydrothermal, Sol-Gel and Ball milling method followed by microwave sintering. To confirm the perovskite formation, BiFeO<sub>3</sub> (BF) samples are characterized by X-ray diffraction analysis, thermo-gravimetric analysis (TGA/DSC/DTA), Fourier transform infrared spectroscopy (FT-IR) and UV-Vis spectroscopy for structural, metal-oxygen bond lengths and optical behaviour of BiFe<sub>2</sub>O<sub>3</sub>. Variation in the morphology of BF due to different synthesis techniques is studied using scanning electron microscopy. The dielectric behaviour of the samples is investigated as a function temperature and frequency in the range of room temperature to 400<sup>o</sup>C and 100 Hz to 5 MHz to evaluate the ferroelectric behaviour of the samples. Magnetic behaviour and mechanical constants are evaluated and discussed in light of the multiferroic behaviour of the ferrites. To study the interaction of acoustic waves with the lattice of BF, the synthesized BF compositions are investigated for their internal friction using the composite piezoelectric oscillator method. The internal friction behaviour of bismuth ferrite is studied in the temperature range of 30<sup>o</sup>C to 400<sup>o</sup>C. Thus, the studies are focused to explore the multiferroic nature and probable applications as an acoustic transducer and delay line.</p> <p>&nbsp;</p> <p>&nbsp;</p> ISHA KAPTE Copyright (c) 2021 ISHA KAPTE https://spast.org/techrep/article/view/1989 Sat, 09 Oct 2021 00:00:00 +0000 Non-antibacterial carbon particles and its fluorescence properties https://spast.org/techrep/article/view/949 <p>Owing to the distinctive morphologies, physiochemical characteristics and wide range of promising applications, carbon materials have become a hot topic in the history of modern nanoscience. Especially, researches in the field of biological applications involving carbon based materials raised a great attention due to its biocompatible physiognomies, chemical stability, high therapeutic outputs and optical absorptivity [1-3]. Carbon, being the most important structural element in human body is also referred to as a carbon-based life form. Henceforth, the utilization of carbon particles in clinical diagnostic and biological assays, can be a safer and simpler alternative for those cytotoxic, carcinogenic and costly synthetic dyes [4-5]. Here in this work, carbon particles are synthesized via a green chemistry approach using corn starch as the precursor. An environmental friendly hydrothermal technique was employed for the preparation of carbon particles (CP) without expending for any tedious purification processes. Also, a simultaneous reduction and functionalization of carbon particles are achieved using lime juice as a catalyst for hydrothermal carbonization. The structural and functional group modifications induced by the catalyst is studied via XRD, FTIR and SEM techniques. The obtained carbon nanoparticles (CP and CP-catalyst) revealed a broad diffraction peak in the range of 15-35° due to the (002) graphitic plane, indicating the occurrence of hydrothermal carbonization. A reduction in the oxygen functional group and Potassium functionalization of CP-catalyst was confirmed through FTIR analysis. SEM images illustrated that the particles are spherical in shape, but the catalyst treated CP exhibited well dispersability. The photoluminescence (PL) behaviour of both the samples was investigated and found an excellent luminescence with excitation independent and dependant properties. The PL lifetime analysis demonstrated that the CP-catalyst possess an enhanced emission decay time that aroused from the accelerated charge transfer process due to the potassium functionalization. As a prerequisite for the understanding of biocompatibility, the antibacterial activity of carbon particles against four bacteria <em>Staphylococcus aureus, Bacillus subtilis, </em>(Gram-positive)<em> and Pseudomonas fluorescence, E. coli </em>(Gram-negative) was further investigated using well-diffusion assay. As shown in Fig. 1 and Table 1, in either of the samples, biocidal activity against tested bacteria was not observed. Thus, the as-synthesized CP with excellent luminescence, good water solubility, high colloidal stability and non-antibacterial properties would be best suited for cell biological applications.</p> <p>&nbsp;</p> <p><img src="https://spast.org/public/site/images/conference21/mceclip0.png"></p> <p><strong>Fig 1</strong>: Antimicrobial activity of the test sample on Microorganisms A-<em>Pseudomonas fluorescence; </em>B- <em>Staphylococcus aureus C-Bacillus subtilis</em>; D- <em>E. coli.</em></p> <p><strong>Table1:</strong> Antimicrobial Activity of S1 and SL1 on Microorganisms</p> <table width="422"> <tbody> <tr> <td width="71"> <p>&nbsp;</p> </td> <td width="114"> <p><em>Staphylococcus aureus</em></p> <p><em>&nbsp;</em></p> </td> <td width="75"> <p><em>Bacillus subtilis</em></p> <p><em>&nbsp;</em></p> </td> <td width="103"> <p><em>Pseudomonas fluorescense</em></p> </td> <td width="59"> <p><em>E. coli</em></p> <p><em>&nbsp;</em></p> </td> </tr> <tr> <td width="71"> <p>S1</p> </td> <td width="114"> <p>0</p> </td> <td width="75"> <p>0</p> </td> <td width="103"> <p>0</p> </td> <td width="59"> <p>0</p> </td> </tr> <tr> <td width="71"> <p>SL1</p> </td> <td width="114"> <p>0</p> </td> <td width="75"> <p>0</p> </td> <td width="103"> <p>0</p> </td> <td width="59"> <p>0</p> </td> </tr> <tr> <td width="71"> <p>DMSO</p> </td> <td width="114"> <p>0</p> </td> <td width="75"> <p>0</p> </td> <td width="103"> <p>0</p> </td> <td width="59"> <p>0</p> </td> </tr> </tbody> </table> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> Annpriya Johnson, Devika Santhosh, Riya Thomas, Elcey C , Manoj B Copyright (c) 2021 Annpriya Johnson, Devika Santhosh, Riya Thomas, Elcey C , Manoj B https://spast.org/techrep/article/view/949 Sat, 18 Sep 2021 00:00:00 +0000 Si9+ ion-irradiation induced modification of structural and magnetic properties of Zn-nanoferrite https://spast.org/techrep/article/view/2065 <p>Swift heavy ion (SHI) irradiation is an important tool to understand ion matter interaction, and to study variation in structural, magnetic, properties. Ion irradiation affects the matter, present in their path by elastic, inelastic collisions and respectively exhibit nuclear energy losses (S<sub>n</sub>) and electronic energy losses (S<sub>e</sub>). Simulation authenticates that in MeV range, S<sub>e</sub> dominates over S<sub>n</sub> in SHI. Effect of irradiation on matter depends on ion species, ion energy and flounce. Spinel ferrites has cubic structure with fcc lattice comprising of two inter-penetrating sub-lattices: sub-lattice A (tetrahedral), sub-lattice B (octahedral) with ~75% empty interstitial sites, therefore energy imparted by ionic irradiation causes cation movement among A and B sites which affects structure and magnetic properties [1, 2] . Spinel structure has shown resistance for SHI as reported in [2].&nbsp; As reported earlier [2], SHI irradiation is also known to alter cationic distribution in ferrites, would reflect change in magnetic properties. Focus of literature available on ZnFe<sub>2</sub>O<sub>4</sub> [2], and references therein, is on exploring structural, magnetic properties. However, literature infrequently reports correlation between magnetic properties, cation distribution, role of ion irradiation to tailor magnetic properties. Therefore, in this work we use x-ray diffraction (XRD); scanning electron microscopy, energy dispersive x-ray spectroscopy (SEMEDS), ); magnetic studies to probe the effect of 120 MeV <sup>28</sup>Si<sup>9+</sup> ion irradiation of ZnFe<sub>2</sub>O<sub>4</sub> by monitoring structural changes, cation distribution, magnetic properties and correlation among them. ZnFe<sub>2</sub>O<sub>4</sub> (ZNF) samples were prepared utilizing Nitrate-Citrate pre-cursors, as described in [2]. Formed dry gel samples were annealed at 450 <sup>o</sup>C/3h, and were used for characterization. SRIM (The Stopping and Range of ions in matter calculation code) is used to calculate penetration depth of ion (R<sub>P</sub>) in ZNF. The R<sub>P</sub> dependence of S<sub>e</sub> ,S<sub>n</sub> (electronic, nuclear energy loss) for ZnF can be seen in figure 1(a). For 120 MeV <sup>28</sup>Si<sup>9+</sup> ion irradiation on ZnF theoretical S<sup>e</sup> is 446 eV/Å and S<sub>n</sub> is 0.3374 eV/Å with R<sub>P</sub> 22.76 µm. To avoid ion implantation sample thickness was selected such that it is less than R<sub>P</sub>. <sup>28</sup>Si<sup>9+</sup> ion irradiation (using 15 UD pelletron accelerator at Inter University Accelerator Center, New Delhi) was done with ion flounce value of 1×10<sup>12</sup>, 1×10<sup>13</sup>, 1×10<sup>14</sup> ions/cm<sup>2</sup>. XRD, SEM-EDS, magnetic data was analysed to get structural parameters, cationic distribution, particle size distribution, and magnetic parameters. XRD (fig. 1b) confirms the formation of spinel nano ferrite (grain diameter: 14.47 nm - 14.84 nm), for pristine, irradiated samples). Fig. 1b (inset) shows XRD of pristine sample, dependence of a<sub>exp.</sub> on irradiation dose, shows linear decrease, described by equation: a<sub>exp.</sub> = 0.84 – 5.6 x10<sup>-4</sup> [Irradiation Dose], showing strong correlation between irradiation dose and a<sub>exp.</sub>. Reduction of a<sub>exp.</sub>, shows irradiation induced shrinkage of spinel unit cell, and is consistent with obtained dislocation density values (range between 0.79 X 1015 - 1.16 X10<sup>15</sup> lines/m<sup>2</sup>). Irradiation shows: i) increase of Oxygen parameter, which is a</p> <p>measure of disorder in the sample (range between 0.3830 – 0.3837), ii) increase of degree of inversion (range between 0.25 – 0.38), ascribed to changes in cationic distribution, iii) reduction of Fe<sup>3+</sup> ions on B-site, with concurrent increase on A-site, while Zn<sup>2+</sup> ions remain more populated on A-site than on B-site, iv) modification of A–O–B, B–O–B, A–O–A super-exchange interaction, which will have effect on magnetic properties, v) increase of coercivity (range between 1452.3 Oe – 2605.4 Oe), is consistent with obtained anisotropy value (range between 0.411´10<sup>3</sup> erg/cc - 1.22 ´10<sup>3</sup> erg/cc), while saturation magnetization range between 4.1 Am<sup>2</sup>/kg - 8.02 Am<sup>2</sup>/kg, ascribable to irradiation induced modification of disorder in the specimen. EDX confirms the uniform allocation of elements, creation of the preferred ferrite phase. Fig. 1(d, e) shows particle size distribution (inset: SEM image) for pristine, irradiated (1´10<sup>14</sup> ions/cm<sup>2</sup>). Sample mean particle size (14.21 nm, 22.58 nm), distribution width (10.36 nm, 25.19 nm) of pristine, irradiated samples shows irradiation induced changes. It is worth noting that, distribution width is an important indicator, as it provides the basis to assess the particle homogeneity, and their lower values correspond to less scattered particle size, and volume. SEM images show particle agglomeration with different shapes, non-uniform particle size dispersal due to magnetic nature of ferrites. Present results clearly show strong correlation between structural properties, cationic distribution, and magnetic properties.<img src="https://spast.org/public/site/images/kane_sn/fig1-cp-kane.png" alt="" width="829" height="545"></p> Chetna, Roshni, Fred, Shashank KANE Copyright (c) 2021 Chetna, Roshni, Fred, Shashank KANE https://spast.org/techrep/article/view/2065 Fri, 08 Oct 2021 00:00:00 +0000 Title Economical Concrete Cube Prepared Using Different Types of Nano- Material for Sustainable Construction https://spast.org/techrep/article/view/1444 <p>In this research work concrete cube has been prepared by doing partial replacement for cement using Nano Materials like Multi-walled Carbon Nano Tubes (MWCNTs), Titanium Di Oxide (TiO<sub>2</sub>) and Copper Oxide (CuO) at different percentages like 0.1, 0.25 and 0.5%. Basic test has been done for materials and fresh concrete followed by Compressive strength test for Concrete Cubes has been conducted. MWCNT gives more Compressive Strength Result compare to TiO<sub>2</sub> and CuO. Just to reduce cement usage Fly Ash has been used as a filler material by keeping the compressive strength and the amount of Nano Materials as constant up to 35% of MWCNTs, TiO<sub>2</sub> and CuO with Fly Ash can be replaced for cement to obtain the Normal Strength. Cost Analysis has been done to find out the economic efficiency of Nano Material Concrete Cube due to which TiO<sub>2</sub> with Fly Ash cost 14.45Rs to prepare single cube as MWCNTs &amp; CuO with Fly Ash cost 726.4 &amp; 17.64Rs to prepare single concrete cube. Almost TiO2 cube preparation took 10% reduction for the preparation of concrete cube compare to Normal Concrete cube has taken 15.96Rs. So we concluded that TiO<sub>2</sub> with Fly Ash Nano Material concrete is the Economical Efficient Concrete compare to MWCNTs and CuO with Fly Ash.</p> RAGHAVENDRA PRASAD H D Copyright (c) 2021 RAGHAVENDRA PRASAD H D https://spast.org/techrep/article/view/1444 Thu, 07 Oct 2021 00:00:00 +0000 First Principles Study of Janus ZrClBr Monolayer under Biaxial Strain https://spast.org/techrep/article/view/2140 <p><span style="font-weight: 400;">After graphene, two-dimensional (2D) materials have emerged as potential candidates to fulfil the demands of new generation optoelectronic, waste heat harvesting, flexible energy storage, and hydrogen production devices [1]. 2D transition-metal dichalcogenides have a chemical formula of MX</span><sub><span style="font-weight: 400;">2</span></sub><span style="font-weight: 400;"> (M = transition metal atom; X = S, Se, or Te), where one layer of M atoms is sandwiched in between of two X atomic layers and can be used in transistors, and electrocatalysts for hydrogen production due to their unique physical and chemical properties [2]. In literature, It is reported that MoS­Se/WSSe/PtSSe monolayers have suitable band gaps for significant absorption efficiency in the visible light range, in turn they can be used as the potential water-splitting photocatalyst [3-5]. Huang </span><em><span style="font-weight: 400;">et. al.</span></em><span style="font-weight: 400;"> theoretically explored the existence of the 2D zirconium dihalide ZrX</span><sub><span style="font-weight: 400;">2</span></sub><span style="font-weight: 400;"> (X = Cl, Br, and I) using first-principles calculations [6]. They reported that ZrX</span><sub><span style="font-weight: 400;">2</span></sub><span style="font-weight: 400;"> shows the dynamic, thermodynamic, and mechanical stability and it can be obtained from its bulk phase through simple mechanical exfoliation.&nbsp; In the recent years,&nbsp; these 2-D materials such as group III, IV and transition metal dichalcogenide (TMDs) monolayers etc. have been found to be emerging materials to be used in thermoelectric,&nbsp; electronic, photo catalytic and &nbsp; optoelectronic applications [7, 8]. Liu et al explored the thermoelectric performance of MNBr (M = Zr, Hf) monolayers and reported that these monolayers as promising candidates to harvest waste heat [9]. It has been investigated&nbsp; that efficiency of these 2-D materials can be tuned by introducing defects, doping, strain and forming heterostructures [10-12]. 2D materials attract the researchers and industry due to their adjustable band gap with the uniaxial or biaxial strain [13]. Recently, Xiong </span><em><span style="font-weight: 400;">et. al. </span></em><span style="font-weight: 400;">[14] investigated the electronic structure and optical properties of the Janus ZrBrCl monolayer.&nbsp;</span></p> <p><span style="font-weight: 400;">In present work, we have studied the effect of biaxial strain on ZrClBr monolayer by first principles calculations based on density functional theory. We have applied compressive and tensile strain ranging from -2 to +2 percent. The structural properties, electronic band structure and density of states have been reported using open-source Quantum ESPRESSO code [15]. Fig. 1 shows the structure of the ZrClBr monolayer used in the present work. Table. 1 shows the calculated lattice parameter, bond length, and band gap for ZrClBr monolayer with and without strain. The calculated lattice parameters of ZrClBr are found in agreement to the already reported results [14]. The dynamical and mechanical stability of monolayers under strain have been checked and found that this monolayer is stable under strain. Fig. 2-4 presents the change in the electronic band structure, total and orbital projected density of states under the applied strain. The electron band structure shows that the ZrClBr monolayer is semiconductor in nature having a band gap of 0.96 eV. It is seen that the band gap increases with the tensile strain and has a value of 1.05 eV at +2% strain, while decreases with the compressive strain and has a value of 0.86 eV at -2% strain.&nbsp;</span></p> <p><span style="font-weight: 400;">Furthermore, the thermoelectric properties of ZrClBr have been calculated using BoltzTrap2 code based on the Boltzmann theory within the semi-classical Boltzmann theory under the constant relaxation time approximation [16]. The Seebeck coefficient and electrical conductivity can be tuned with the application of applied strain, as the transport coefficient depends upon&nbsp; the degeneracy and shape of the bands. From the calculated Seebeck&nbsp; coefficient (S)&nbsp; and electrical conductivity (σ), the power factor (S</span><sup><span style="font-weight: 400;">2</span></sup><span style="font-weight: 400;">σ) has been evaluated at the different carrier concentrations of electrons and holes. Fig. 5. shows that the value of power factor for n-type&nbsp; (p-type) ZrClBr monolayer increases under tensile (compressive) strain. The results show that the thermoelectric properties can be tuned with the application of strain.</span></p> Janpreet Singh Sidhu, Gurinder Singh, Surya Kant Tripathi Copyright (c) 2021 Janpreet Singh Sidhu, Gurinder Singh, Surya Kant Tripathi https://spast.org/techrep/article/view/2140 Fri, 08 Oct 2021 00:00:00 +0000 Starch Based Biodegradable Polymer Nanocomposite for Packaging Application https://spast.org/techrep/article/view/2691 <p>Petroleum based packaging materials are widely used for packaging application so far which are one of the major concerns for environmental pollution. The use of biodegradable polymers for packaging is one of the currently growing research areas [1,2]. In this investigation biodegradable starch-based polymers are prepared by blending with polyvinyl alcohol (PVA) for packaging applications. In-order to improve mechanical properties of blends, crystalline nanocellulose (CNC) is incorporated to form nanocomposite [3,4]. Starch-based nanocomposite films were prepared by solution casting technique. &nbsp;Additives such as glycerol and citric acid are added to improve flexibility and processability of starch based polymers. Polymer blends were characterised for mechanical properties (tensile strength) and structure (X-ray diffraction). Improvement in tensile strength is observed for starch-PVA nanocomposite. The photograph of the transparent film casted using flat sheet casting machine is seen in Fig. 1(a). The&nbsp; 50/50&nbsp; (wt/wt)&nbsp; starch/PVA&nbsp; blend&nbsp; composition&nbsp; gives&nbsp; good&nbsp; set&nbsp; of&nbsp; tensile&nbsp; strength&nbsp; and elongation properties. Thus nanocomposite films were prepared with 1 wt% and 3 wt% CNC using&nbsp; 50/50&nbsp; (wt/wt)&nbsp; starch/PVA&nbsp; blend.&nbsp; An&nbsp; increase&nbsp; in&nbsp; tensile&nbsp; strength&nbsp; of&nbsp; 11.25 MPa&nbsp; is exhibited&nbsp; by&nbsp; nanocomposite&nbsp; film&nbsp; at&nbsp; 3&nbsp; wt%&nbsp; CNC as shown in Fig. 1.</p> <p>&nbsp;</p> <p><strong>Figure 1.</strong> (a) Photograph of casted starch/PVA nanocomposite film and (b) Force vs extension plot of starch/PVA blend and nanocomposite films</p> <p>Polymers&nbsp; used&nbsp; in&nbsp; this&nbsp; investigation&nbsp; were&nbsp; thermoplastic&nbsp; starch&nbsp; and&nbsp; polyvinyl&nbsp; alcohol&nbsp; (PVA). Plasticiser&nbsp; such&nbsp; as&nbsp; glycerol&nbsp; and&nbsp; citric&nbsp; acid&nbsp; are&nbsp; added&nbsp; to&nbsp; to improve the flexibility of starch.&nbsp; Crystalline&nbsp; nanocellulose (CNC)&nbsp; is utilised as nanofiller&nbsp; in this&nbsp; investigation. The films of uniform thickness were fabricated using flat sheet film casting machine using doctor blades. Table 1 gives the composition of&nbsp; blend, plasticizers and CNC.</p> <p>Table 1: composition chart</p> <table width="106%"> <tbody> <tr> <td width="20%"> <p><strong>Sample Code</strong></p> </td> <td width="11%"> <p><strong>Starch</strong></p> <p><strong>(wt%)</strong></p> </td> <td width="11%"> <p><strong>PVA</strong></p> <p><strong>(wt%)</strong></p> </td> <td width="14%"> <p><strong>Glycerol</strong></p> <p><strong>(wt% of starch)</strong></p> </td> <td width="14%"> <p><strong>Citric Acid</strong></p> <p><strong>(wt% of starch)</strong></p> </td> <td width="12%"> <p><strong>CNC</strong></p> <p><strong>(wt% of starch)</strong></p> </td> <td width="15%"> <p><strong>Avg. Thickness</strong></p> <p><strong>mm</strong></p> </td> </tr> <tr> <td width="20%"> <p>&nbsp;</p> <p>ST-PVA 50-50</p> </td> <td width="11%"> <p>&nbsp;</p> </td> <td width="11%"> <p>&nbsp;</p> </td> <td width="14%"> <p>&nbsp;</p> <p>25</p> </td> <td width="14%"> <p>&nbsp;</p> </td> <td width="12%"> <p>&nbsp;</p> </td> <td width="15%"> <p>&nbsp;</p> <p>0.106</p> </td> </tr> <tr> <td width="20%"> <p>ST-PVA 1%</p> </td> <td width="11%">&nbsp;</td> <td width="11%">&nbsp;</td> <td width="14%"> <p>25</p> </td> <td width="14%">&nbsp;</td> <td width="12%">&nbsp;</td> <td width="15%"> <p>0.080</p> </td> </tr> <tr> <td width="20%"> <p>ST-PVA 3%</p> </td> <td width="11%">&nbsp;</td> <td width="11%">&nbsp;</td> <td width="14%"> <p>25</p> </td> <td width="14%">&nbsp;</td> <td width="12%">&nbsp;</td> <td width="15%"> <p>0.105</p> </td> </tr> </tbody> </table> <p>&nbsp;</p> <p>Starch/PVA blends and CNC nanocomposite were successfully prepared by solution casting technique. Blends of 50/50 (wt/wt) starch/PVA were utilised for nanocomposite due to good set of tensile strength and elongation values. An increase in tensile strength of 59% (11.25 MPa) is observes for 3wt% CNC nanocomposite. Thus Strach/PVA based CNC nanocomposite can be utilised for packaging application.</p> Vishesh Iyengar Copyright (c) 2021 Vishesh Iyengar https://spast.org/techrep/article/view/2691 Thu, 21 Oct 2021 00:00:00 +0000 Fast Fluoride Ion Transport in Mechanochemically Synthesized MSn2F5 (M: Na, K and NH4) Solid Electrolytes on Fluoride Ion Battery Applications https://spast.org/techrep/article/view/1291 <p>Investigations on fast fluoride ion conducting solid electrolytes are gaining much scientific attention recently for the development of all-solid-state fluoride ion batteries (FIBs) as an alternative to Li-ion batteries [1]. SnF<sub>2 </sub>based solid electrolytes often exhibit good ionic conductivity at room temperature [2]. Unlike MSnF<sub>4</sub> (M: Pb and Ba) systems, the reports on MSn<sub>2</sub>F<sub>5</sub> solid electrolytes are limited in the literature. Earlier studies show the synthesis of solid fluoride materials either by solid state reaction or coprecipitation methods. However, mechanical milling technique is recently found to be a promising synthesis route for fluoride-based materials [3].</p> <p>In the present work, the superionic MSn<sub>2</sub>F<sub>5</sub> (M: Na, K and NH<sub>4</sub>) materials are prepared by mechanical milling technique. The X-Ray Diffraction studies confirm the successful formation of the materials showing single phase without any trace of secondary phases. Differential Scanning Calorimetry (DSC) results confirm the absence of phase transition in NaSn<sub>2</sub>F<sub>5</sub> and the presence of superionic phase transition in KSn<sub>2</sub>F<sub>5</sub> (430 K) and NH<sub>4</sub>Sn<sub>2</sub>F<sub>5</sub> (340 K). Ionic conductivity measurements are carried out at different temperatures and frequencies using impedance spectroscopy. Unlike NaSn<sub>2</sub>F<sub>5</sub>, a change in conductivity is observed in the temperature dependent conductivity plots for both KSn<sub>2</sub>F<sub>5</sub> and NH<sub>4</sub>Sn<sub>2</sub>F<sub>5</sub> corresponding respectively to their superionic transition temperature as observed in DSC [<strong>Fig. 1</strong>]. Among the investigated materials, NaSn<sub>2</sub>F<sub>5 </sub>exhibits lower ionic conductivity due to its rigid crystal structure arising from the strong polarization of fluoride ions by the sodium ions, where as NH<sub>4</sub>Sn<sub>2</sub>F<sub>5 </sub>exhibits the highest ionic conductivity.&nbsp; The differences in their transport results are explained with respect to their respective crystal structures and ionic radii of cations. The present results show the strong potential of KSn<sub>2</sub>F<sub>5</sub> and NH<sub>4</sub>Sn<sub>2</sub>F<sub>5</sub> materials as promising solid electrolytes for all solid-state FIBs.</p> K Ramakrushna Achary Copyright (c) 2021 K Ramakrushna Achary https://spast.org/techrep/article/view/1291 Fri, 01 Oct 2021 00:00:00 +0000 Multimodal emission in Tb3+/Yb3+ co-doped Y2O3 phosphor: Down-conversion, Downshifting and Quantum cutting https://spast.org/techrep/article/view/2823 <p>In designing, a Tb<sup>3+</sup>–Yb<sup>3+</sup> co-doped down conversion luminescent convertor for crystalline Si solar cells, a better sensitizer of Tb<sup>3+</sup> should be found so that energy cannot be transferred to Yb<sup>3+</sup> ions and the concentration quenching effect of Yb<sup>3+</sup> should be reduced to enhance Yb<sup>3+</sup> emission [1]. Co-operative energy transfer (CET) has been ascribed as the possible mechanism for QC; as a result of which a UV/blue photon absorbed by a Tb<sup>3+ </sup>ion splits into two near infrared photons(wavelength range 950–1000 nm) emitted by a Yb<sup>3+</sup> ion pair. This process can diminish the energy loss related to the thermalization of hot charge carriers after the absorption of a high-energy photon. By cutting one high energy photon into two low-energy photons, this can both be absorbed by the solar cell, current doubling is obtained in the upper region of the solar spectrum, which consists of photons with energies exceeding 2 eV. We have explored the possibilities of efficient down-conversion of a single visible or ultraviolet photon into two near-infrared (NIR) photons using lanthanide ions [2- 4]. The unique and rich energy-level structure of these ions allows for efficient spectral conversion, including up- and down-conversion processes mediated by resonant energy transfer between neighbouring lanthanide ions. Considering the energy levels of all lanthanides, depicted in the so-called Dieke energy level diagram [5-6].</p> <p>A Quantum Cutting phosphor, Y<sub>2</sub>O<sub>3 </sub>co-doped Tb<sup>3+</sup>/Yb<sup>3+</sup> prepared by a solution based approach. The phase analysis by powder XRD, measurement of SEM images, Steady State and Time Resolved Photoluminescence study has been investigated in detail. A cubic of Y<sub>2</sub>O<sub>3</sub>:Tb<sup>3+</sup>, Yb<sup>3+</sup> phosphor show a pure phase by X-Ray diffraction and Photoluminescence emission (PL) spectra reveals the efficient emission in the green region which corresponds to <sup>5</sup>D<sub>4</sub>→<sup>7</sup>F<sub>6 </sub>transition of Tb<sup>3+</sup> ion. The down conversion phosphor of Tb<sup>3+</sup>, Yb<sup>3+</sup> co-doped Y<sub>2</sub>O<sub>3</sub>, energy transfer mechanisms of Tb<sup>3+</sup>→Yb<sup>3+</sup> in the UV/blue region were investigate. Tb<sup>3+ </sup>ions can be effectively excite due to its <sup>4</sup><em>f</em><sub>7, </sub><sup>5</sup>d<sub>1</sub> state and relaxed down to the <sup>5</sup>D<sub>4</sub> level, from which the energy is transferred cooperatively to two neighbouring Yb<sup>3+. </sup>&nbsp;The addition of Yb<sup>3+</sup> in the Tb<sup>3+ </sup>doped Y<sub>2</sub>O<sub>3 </sub>samples the emission intensity of Tb<sup>3+</sup> continuously reduce in the visible region as well as in the NIR region while the intensity of the Yb<sup>3+</sup> first increases 5 mol % and then decreases, this reflects the energy transfer from Tb<sup>3+</sup> to Yb<sup>3+</sup> ions and concentration quenching. The decay curve of different samples reveals an efficient cooperative energy transfer from Tb<sup>3+ </sup>to Yb<sup>3+ </sup>ions due to <sup>5</sup>D<sub>4</sub> – <sup>7</sup>F<sub>5</sub> transition. It is monitored 1000 nm at λ<sub>ex= </sub>488 nm for Tb<sup>3+</sup> emission. Furthermore we have measured Yb<sup>3+</sup> and Tb<sup>3+</sup> monitored 1000 nm and 550 nm at λ<sub>ex</sub> = 920 and 488 nm. The energy transfer from Tb<sup>3+ </sup>to Yb<sup>3+</sup> in Y<sub>2</sub>O<sub>3</sub>:Tb<sup>3+</sup>(5 mol %), Yb<sup>3+</sup>(5 mol %) sample has been calculated to be 75.01 % and the corresponding Quantum Cutting Efficiency was calculated to be 175.01%. From the life time measurement, Energy Transfer Efficiency and the rate of Energy Transfer with respect to Yb<sup>3+</sup> concentration have been investigated. The possible mechanisms involved in different transitions and energy transfer processes can be understood using a schematic energy level diagram The Yb<sup>3+</sup>concentration dependent ET efficiency and QC efficiency has also been evaluated.</p> <p>&nbsp;</p> Dr. Prachi Tadge Copyright (c) 2021 Dr. Prachi Tadge https://spast.org/techrep/article/view/2823 Sun, 17 Oct 2021 00:00:00 +0000 Numerical analysis of residual stresses in additively manufactured materials https://spast.org/techrep/article/view/2454 <p>For more than two decades powder bed fusion Additive Manufacturing (AM) techniques have been employed for aerospace, biomedical and automotive applications. In the AM process, material is joining usually layer upon layer to make object from a 3D model. &nbsp;As new layers of material are deposited, heat is conducted away from the recently solidified material, through the previously melted layer and surrounding powder, inducing thermal cycles. These thermal cycles can influence the microstructure, crystallographic texture, phase transformation kinetics and residual stress state [1].</p> <p>A tensor field of residual stresses is present in an AM part when it is free of any external load. This is caused mainly by the existence of non-constant distribution of thermal strain where corresponding stresses induce a heterogeneous plastic response in the material. The residual stresses can be classified into</p> <ul> <li>macro residual stresses, which are developed in several grains.</li> <li>micro residual stresses, which are developed in one grain (for example caused by martensitic transformation).</li> <li>sub micro residual stresses, which are developed within several atomic distances of the grain (caused by crystalline defects such as dislocations and vacancies)</li> </ul> <p>Since the thermal history of the material in the deposited part is different from point to point and depends on the deposition parameters and build-up strategy, the finished part may present complex distributions of microstructures and properties [2-4].</p> <p>Our group conducted numerical analysis of the thermal field and heat flux vector during the multi-layer deposition of Ti6Al4V alloy [1]. In the current work, we present structural analysis with numerical determination of residual stress in AM parts. A three-dimensional model, considering multi layers and various interlayer time intervals was developed. Each layer was created by adding elements on the base of the laser trajectories. The trajectories in the odd layers were rotated by 90°. The Newton Raphson method (Fig.1) was used to solve the system of nonlinear equations. Fig. 2 show results of the calculated residual equivalent Von Misses stress field distributions considering 12s interlayer time interval. A good agreement between numerical and experimentally determined data was found.</p> <p>Our work revealed that short-time interlayer intervals cause reduction of residual stress in AM parts. The results of the numerical modelling can be used for process optimisation.</p> Ladislav Novotný, Miloslav Béreš, Bruno Carpentieri, Hamilton Ferreira Gomes Abreu Copyright (c) 2021 Ladislav Novotnyý, Miloslav Béreš, Bruno Carpentieri, Hamilton Ferreira Gomes Abreu https://spast.org/techrep/article/view/2454 Wed, 13 Oct 2021 00:00:00 +0000 Fire retardant nanocoatings for wooden structures https://spast.org/techrep/article/view/332 <p>Wood is one of the natural resources that is used as a construction material since time immemorial. Most of the buildings in Western/European countries are completely constructed with wood [1]. Wooden constructions are cost-effective, lightweight, easy to construct, and can withstand natural calamities [2]. These constructions catch and transfer fire rapidly. It can also generate a considerable quantity of smoke and poisonous fumes when burned. In the year 2018-2019 American fire department reported more than 1.3 million cases of fire which caused 3,655 damages, 15,199 injuries, and around USD 25.6 billion property loss [5]. Existing fireproof coatings are toxic and release harmful gases when burnt leading to environmental pollution [4]. Hence the development of eco-friendly fire retardant nanocoatings is gaining importance.</p> <p>Nanocoatings are the thin layer coatings that are used to preserve the outer layer of different building materials such as wood/timber and other materials. It also prevents corrosion and provides resistance to climatic changes. Nanomaterials such as silicon dioxide, carbon nanotubes, and aluminum oxide are commonly employed as fire-retardant materials on the surfaces such as wood, textiles, plastic, metal, and cement [1].</p> <p>This review article brings out the application of nanotechnology for the fire safety of buildings. The use of fireproof nano-coated textiles/fabrics as depicted in figure 1, &nbsp;and paints consisting of fireproof nanomaterials make the wood/timber fireproof. The nanomaterials that bring in the fire retardant property, development of coatings using such materials, technologies such as HefCel as shown in figure 2 and in-situ polymerization, the use of materials such as carbon nanotubes, nano-silica, nano clay, etc to bring the fire retardant properties to wood, are discussed in detail.</p> Ujwal Shreenag Meda, Deekshasushmith S, Manjunatha C Copyright (c) 2021 Ujwal Shreenag Meda, Deekshasushmith S, Manjunatha C https://spast.org/techrep/article/view/332 Tue, 14 Sep 2021 00:00:00 +0000 Synthesis of fluorescent carbon dots doped graphitic carbon nitride and its application as Fe3+ sensors https://spast.org/techrep/article/view/2083 <p>Carbon dots (C-dots) have better water solubility, biocompatibility, environmental friendliness, and non-blinking fluorescence than any other materials [1]. Due to the numerous advantages of carbon quantum dots (CQDs) over semiconductor quantum dots, studies on synthesis and fluorescence-based sensing in biocompatible carbon quantum dots (CQDs) have recently become a frequently discussed field of research.&nbsp; In this work, photoluminescent small sized Carbon dots doped graphitic carbon nitride have been synthesised through hydrothermal method as well as their potential application in sensing of Fe<sup>3+</sup> selectively [4]. Water-soluble carbon quantum dots (CQDs) are synthesized via citric acid and urea, graphitic carbon nitride is simply synthesised through melamine. The photoluminescence properties of Carbon Dot, graphitic carbon nitride (g-C<sub>3</sub>N<sub>4</sub>), Carbon dots doped (g-C<sub>3</sub>N<sub>4</sub>), have been studied, and the results show that they have a strong blue luminescence with excitation wavelength independent, pH sensitive, and ionic strength dependent luminescence features. The as-prepared CQDs generated a vivid blue fluorescence with a strong emission at 450nm and a 335 nm excitation. The fluorescent carbon dots and composite not only&nbsp;exhibit good photoluminescence capabilities and water solubility, but they also demonstrated an extraordinary multifunctional fluorescence sensor for pH probing and&nbsp;(Fe3+) ion&nbsp;detecting applications. Various spectroscopic techniques were used to analyse the morphological structure, optical characteristics, and chemical compositions of Carbon dots, graphitic carbon nitride and carbon dots doped graphitic carbon nitride composites, including fluorescence spectrometer, X-ray diffraction (XRD), Scanning electron microscope (SEM), Fourier transform infrared spectrometer (FTIR). &nbsp;Metal ion pollution has become a pressing concern in the environmental field due to the grave harm they pose to our natural environment and human health. iron is one of the hazardous metal ions, and its stability causes significant damage to our environment and health. A wide range of analytical methods, including atomic absorption and emission spectroscopy (AAS, AES) [3], inductively coupled plasma mass spectrometry, have been developed in recent years for the detection of with excellent sensitivity and precision. In comparison to other methods, fluorescence spectroscopy is preferred because of its great sensitivity, superior selectivity, ease of operation, and low cost.</p> <p>&nbsp;</p> <p>The obtained CQDs have higher photoluminescence of quantum yield (QY = 54.8%, quinine sulphate as standard).&nbsp; At room temperature, the fluorescence of C-dots doped graphitic carbon nitride could selectively quenched by Fe<sup>3+</sup> within seconds than the graphitic carbon nitride alone. Only the addition of Fe <sup>3+ </sup>caused the fluorescence quenching by destroying the surface imperfections of C-dots. Surface flaws are unaffected by the presence of other common interfering metal ions documented in earlier research like Ag<sup>+</sup>, Cu<sup>2+</sup> etc. The detection mechanism is based on the inner filter effect (IFE) and it shows excellent linear static quenching [2]. By the addition of ascorbic acid as a reducing agent, the reversible switching in the fluorescence was examined, and a very good recovery in fluorescence was observed for up to three consecutive cycles.[3]. Carbon dots showing higher fluorescence is already reported in several papers, but carbon dots doped graphitic carbon nitride showing fluorescence is the first time studying. Carbon dots doped graphitic carbon nitride showing slightly higher fluorescence intensity than graphitic carbon nitride.</p> Silpa Sunil Erattu Copyright (c) 2021 Silpa Sunil Erattu https://spast.org/techrep/article/view/2083 Wed, 17 Nov 2021 00:00:00 +0000 Rapid photocatalytic toxic dye degradation and ORR study of NiFe codoped CuO https://spast.org/techrep/article/view/2156 <p>NiFe&nbsp; co-doped CuO was synthesized using the sol-gel method [1]. The structural, optical band gap and light-sensing [2] (UV and RGB (red, green, and blue)) performance of Cu<sub>1-<em>x</em></sub>(Ni<sub>0.5</sub>Fe<sub>0.5 </sub>)<em><sub>x</sub></em>O with x=0.0078, 0.0156, 0.0234, 0.0312 ) were investigated in detail. In this study samples hereafter named as: <em>CuO, NiFe-0.0078, NiFe-0.0156, NiFe-0.0234, and NiFe-0.0312</em>. Agglomerated (NPs) and elongated nanowire and nano sphere have been synthesized using the sol-gel technique[3]. The crystalline structure of the NPs has been studied by using X-ray diffraction (XRD) analysis [4]. Raman spectra of samples confirm the present phonon modes support the XRD results. NiFe co-doping was found to modify the lattice parameters <em>(a ≠ b ≠c),</em> bond-lengths, bond-angles, and % lattice strain of the CuO NPs. With doping of it was observed tha<em>t</em> there is constant shrinkage in the Unit lattice. The bond length and the lattice parameters&nbsp;decrease when the doping concentration is increased.&nbsp; This is possible because of less ionic radii of both Ni and Fe then that of Cu. As a result the lattice contracts and the volume of the unit cell decreases continuously. The bandgap has shown the decreasing trend from lower doping to the higher one. Though the change was nominal, it decreased for NiFe-0.0078 and then nominally increased for the higher doping and at the end decreased for NiFe-0.0312.&nbsp; The defect was also observed to be higher for the lowest doping which then nominally decreased as the doping is increased. This might be possible because of Ni influence in the lower doping and there is possibility of Fe to be in +2 states. This results in the V<sub>O </sub>in the system and thereby reducing the bandgap. But in going towards the higher doped sample the Fe tries to dominate and hence it is possible it is trying to maintain its charge state of +3[5]. Therefore the O<sub>i</sub> increases in the system and hence the conductivity is increased as we go towards the higher doping. The conductivity is slightly reduced for the higher doping of 0.03125. This might be due to both types of defects trying to influence the system resulting in reduced conductivity then 0.0234.</p> <p>The photocatalytic activities of NiFe samples were investigated from the absorption (%) data using a Research India UV-vis spectrophotometer, on Methylene Blue, Methylene Orange and Rhodamine in presence of an 11W UV lamp with a wavelength ~290 nm. Approximately ~20mg of all samples were added as a catalyst into 20 ppm dye aqueous solution under constant stirring at room temperature. The adsorption/desorption of solutions was obtained by stirring at 30 min. The photocatalytic degradation of samples was tested in an interval of 10min for 90 min. A 2ml solution was extracted from the entire photo-reacted solution at every 10 min interval for 90 min. The absorption spectra of these activated samples were tested in the absorption range of dye. The changes in dye concentration due to UV photo-irradiation were evaluated from the difference in the absorption spectra.&nbsp;It has been reported that the catalytic removal of in the presence of H<sub>2</sub>O<sub>2 </sub>follows a radical oxidation pathway. This pathway may be taken due to hydrogen peroxide being a source of OH<sup>-</sup> and O<sub>2</sub>• radicals when decomposed in the presence of a catalyst.</p> <p>The oxygen reduction reaction (ORR) is one of the key reactions in various clean energy technology devices such as fuel cells, metal-air batteries, and water electrolyser [6]. In this context, Copper has been less explored owing to its low catalytic activity and stability [R5]. However, recently, different composites of copper and carbon materials, copper based enzymes, Cu centered metal organic framework have been explored as ORR electrocatalyst [7]. For instance, Yu et al. designed a hybrid of CuO/graphene electrocatalyst with significant catalytic activity towards ORR. Copper complex of 5-nitro phenanthroline sandwiched between polyvinyl imidazole layers enclosed with the carbon nanotube showed ORR catalytic activity on a par with Pt in alkaline solution [8]. Ania et al. reported Cu/GO hybrid catalysts with excellent oxygen reduction activity in terms of high methanol tolerance and long term stability. Bimetallic Ag-Cu alloy with enhanced ORR and OER catalytic activity than their counterparts was reported by Ashok et al. Here, this study aims to investigate the electro catalytic activity of pure and doped CuO towards ORR. The electrocatalytic activity of the undoped and doped samples was evaluated by cyclic voltammetry method [9].To understand ORR kinetics, the RDE polarization curve of the samples was recorded in O<sub>2</sub> saturated 0.1 M KOH solution at 1600 rpm. As shown in Figure 1b CuO-NiFe-0.0078 displayed enhanced ORR activity than that of other samples in terms of onset potential (-0.18) and a positive shift of 10 mV in the half-wave potential. The improved ORR activity of CuO-NiFe-0.0078 was attributed to its decrease in band gap and presence of higher amount of defects.</p> Prashant Mishra, Rachit Dobhal, Swarna Prava Mantry, Varadwaj K.S.K., Somaditya Sen Copyright (c) 2021 Prashant Mishra, Rachit Dobhal, Swarna Prava Mantry, Varadwaj K.S.K., Somaditya Sen https://spast.org/techrep/article/view/2156 Fri, 08 Oct 2021 00:00:00 +0000 Extraction of Cellulose Nanofibers from Agricultural Waste as Future Nanomaterials https://spast.org/techrep/article/view/1160 <p>Natural materials are experiencing a renaissance of sorts, as people around the world seek safe, environmentally friendly and renewable alternatives to plastics and other oil-based products. The use of eco-friendly and bio-based materials is a green concept in material science research. Nanocellulose is the most promising sustainable solution for several future challenges in modern society [1]. Toxic nanofillers would effectively be replaced with nanocellulose and this extend their application in biomedical area. Cellulose nanofiber (CNF), which can be derived from plant, is one of the most abundant green resources on Earth. Several plant parts are used to extract cellulose nanofibers. Herein, we have adopted an eco-friendly method to extract cellulose nanofibers by making use of wealth from waste concept. In the current research, cellulose nanofibers were successfully extracted from onion skin and garlic straw, which are popular agricultural waste from food processing industry via. a simple and economic method. There are five steps involved in the extraction process (<strong>Fig.1</strong>). The alkali treated fibers are bleached with 10% NaOH and 15% hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>). Later on acid hydrolysis stage, the bleached fibers were treated with oxalic acid in an autoclave. Finally, the obtained fibers are homogenized in a homogenizer until the fibers are uniformly and further making it into nanoscale dimension. The extracted cellulose nanofibers are characterized using Scanning Electron Microscopy (SEM), Dynamic light scattering (DLS) and <sup>13</sup>C&nbsp;<em>NMR spectroscopy</em> techniques. The prepared nanofibers are of high purity, nanoscale dimension and high aspect ratio, which would have potential application in a variety of fields including filter material, high gas barrier packaging material, electronic devices, foods, medicine, cosmetics, photonic materials and health care [2]. Due to the renewable and sustainable nature of cellulose nanofibers, it creates low environmental impact in its production and disposal.</p> Poornima Vijayan P, Arsha M R, Asha Bhanu A V, Vijayalekshmi V, Midhun Dominic C. D Copyright (c) 2021 Poornima Vijayan P, Arsha M R, Arsha M R, Asha Bhanu A V, Vijayalekshmi V, Midhun Dominic C. D https://spast.org/techrep/article/view/1160 Fri, 24 Sep 2021 00:00:00 +0000 Freestanding N-Mo-S hybrid films for efficient oxygen evolution reaction https://spast.org/techrep/article/view/600 <p>The rapid development of the global economy promotes the increasing use of fossil fuels accompanied by serious environmental pollutions. [1] It is vital to develop sustainable and clean energy resources such as solar light, wind, and hydropower. These resources, however, are intermittent and have limited utilization due to the local conditions and geology. As an alternative method, electricity from the above energy resources can be efficient stored in hydrogen through water electrolysis. Hydrogen is a clean energy resource and has high energy density. It has important applications in fuel cells in the transportation tools world widely. Electrocatalytic water splitting for the sustainable hydrogen production is moving to practical application and contributing to global decarbonization. While the slow kinetics in oxygen evolution reaction (OER) has limited the overall performance of water splitting. [2] Therefore, it is important to develop active OER catalysts with low-cost and high efficiency.</p> <p>&nbsp;</p> <p>Transition metal elements are abundant on earth and can be manipulated to prepare highly active OER electrocatalysts by the incorporation of non-metal elements like N, S, P and C. Graphitic-N is a kind of n-doping and can enhance the absorption of O atom. [3] And it also improves the catalysts' electrical conductivity, creating abundant active sites. [4] Recent studies have shown that S-vacancies of MoS<sub>2</sub> films could also act as active sites and contribute to the catalytic activity.</p> <p>&nbsp;</p> <p>Mo-based catalysts are always used to HER, a few apply to OER. Recently, some researchers found that Mo-based catalysts also have a good performance in OER. Zhang and co-worker recently reported an MoS<sub>2</sub>/Ni<sub>3</sub>S<sub>2 </sub>heterostructures with abundant interfaces for complete water splitting. [5] For OER, it has a low overpotential of 218 mV at 10 mA/cm<sup>2</sup>. Amiinu and co-worker reported a Mo–N/C@MoS<sub>2</sub> with an overpotential of 390 mV to achieve the current density of 10 mA/cm<sup>2</sup>. [6]</p> <p>In this study, an efficient OER catalyst of nitrogen doped MoS<sub>2</sub> hybrid nanosheets on stainless steel mesh is developed and employed as a freestanding electrode. At optimal doping levels, the as-prepared electrode exhibits a low overpotential of 257 mV at 10 mA cm<sup>-2</sup> and high stability toward OER in alkaline electrolyte. The high activity is originated from the nitridation treatment which not only increases the number of active sites, but also lowers the interfacial energy barriers to boost the surface kinetics. The present study has provided a useful method to prepare high performance OER electrocatalyst for practical application</p> Zhe Wang Copyright (c) 2021 Zhe Wang https://spast.org/techrep/article/view/600 Sun, 19 Sep 2021 00:00:00 +0000 Nitrogen Phosphorous co-doped carbon quantum dots scaffolded on TiO2 nanoparticles towards efficient photocatalyst for hydrogen production https://spast.org/techrep/article/view/1755 <p>Now a days depleting the non-renewable energy resources, increase in the energy efficient and cost-effective energy materials in field of nano materials. Environmental and energy concerns have attracted significant attention to develop new kind of energy materials for our future energy needs[1]. In this situation hydrogen is emerged as most promising candidate for fulfilment future energy consumption applications [2]. The production of hydrogen by splitting of water is most challenge in recent years, among several hydrogen production methods, Hydrogen production using photocatalyst has been widely explored as a promising technology for our future to elucidate the worldwide energy crisis and environmental pollutions [3]. However, its use is still limited by the lack of efficiency and stability of the Photocatalyst. To date, researchers are searching for an efficient, stable, and earth abundant solar spectra driven photocatalyst material which is able harvest solar energy. Numerous metal-based semiconductor materials were developed as a photocatalyst to harvest solar energy because of their long-lasting lifetime and very good energy-conversion efficiency [4], like Sr-TiO<sub>3</sub>, TiO<sub>2</sub>,&nbsp; ZnO, and nanocomposites of those semiconductors are reported. However, these semiconductor materials suffer from some common limitations like, wide bandgap, energy position of conduction band lower than the reduction potential of protons, instability, and high cost. Many of the disadvantages of the preceding ideas can be overcome by introducing CQDs and, nitrogen, phosphorus co-doped CQDs on TiO<sub>2</sub>. Herein, we developed a facile synthesis of Nitrogen phosphorous co doped carbon quantum dots scaffolded on TiO<sub>2</sub> nanocomposites as efficient photocatalyst for hydrogen production. The developed NPCQD-TiO<sub>2</sub> photocatalysts shows improved visible light photocatalytic hydrogen production of 533mmolh<sup>-1</sup>g<sup>-1</sup> which is 11times higher as compared to bare TiO<sub>2</sub>. It has been found that optimising the NPCQD on TiO<sub>2</sub> successfully tunes the bandgap and up conversion capabilities of the heterostructures, enabling unique photon harvest, Ultraviolet photoluminescence spectroscopic results reveal that decrease in the work function of NPCQD-TiO<sub>2</sub> due to new energy levels created by NPCQDs above the valance band of TiO<sub>2.</sub> which is validated by first principles Density Functional Theory (DFT) calculations. Mott-Schottky plots. Time resolved photoluminescence spectroscopy results shows increase in carrier lifetime of photo generated electron hole pairs are responsible for improved Photocatalytic hydrogen production of NPCQD-TiO<sub>2</sub> photocatalysts.</p> YASHWANTH H J, hareesh.K Copyright (c) 2021 YASHWANTH H J, hareesh.K https://spast.org/techrep/article/view/1755 Sat, 09 Oct 2021 00:00:00 +0000 Experimental Investigations on Durability Characteristics of Bamboo Fiber Reinforced Self Compacting Concrete with GGBS & Allcofine https://spast.org/techrep/article/view/1406 <p>As cement being costly and producing lot of CO<sub>2</sub> while manufacturing and mixing in the concrete. Alternative materials are required to produce the same strength as cement and which is eco material saves the environment also. For that best chosen material GGBS. It’s a waste material which replaced is added to produce high strength concrete along with optimized percentage of alccofine. The objective of the current investigations is evaluate the strength and durability performance of the self-compacting concrete with GGBS, alccofine and inclusion of 1 % bamboo fibers which produce less CO2 emissions. Durability performance is evaluated based on the impact of chemical immersion period of 30,60,90 days on weight of concrete and compressive strength. The comparative assessment with BFRSCC and NSCC was done by observing the significant increase in resistance to loss in compressive strength and weight against sulphate and acid attack up to 90 days with 5% H2SO4 and Na2SO4 solution, later it started degrading on the surface. The compressive strength of NSCC and BFRSCC with GGBS and alccofine before and after exposing to the acid for 90 days duration was observed as 9% reduction. The weight loss index for NSCC is 1.02 and BFRSCC&nbsp;is 1.0. It creates the impression that in the Sulphuric acid attack, the early disintegration of calcium hydroxide and resulting development of layer measure of gypsum are ascribed to the dynamic weakening joined by the scaling and softening of the matrix. The compressive strength of NSCC and BFRSCC before and after exposing to the Alkaline&nbsp; for 90 days duration was observed as 10% reduction. Alkaline resistance of BFRSCC Increase as the rate of weight reduction,diminishes as the number of submersion days increments which means that indication of durability. The weight reduction index for BFRSCC&nbsp;is 1 and NSCC is 0.52. The durability performance&nbsp; BFRSCC was good due to the utilization of GGBS and alccofine.Micro fine minerals&nbsp;which will be acting as pore filler the concrete becomes denser and thus won’t allow water to penetrate but increase the strength. Since the bamboo fibers degrade under moist condition the best solution is using GGBS and alccofine which finally increases durability resulted in Sustainable fiber reinforced concrete.</p> Dr.S.Kavitha Copyright (c) 2021 Dr.S.Kavitha https://spast.org/techrep/article/view/1406 Sat, 09 Oct 2021 00:00:00 +0000 State of the Art Report on Light Gauge Steel-Concrete Composite Columns Infilled with Self Compacting Concrete https://spast.org/techrep/article/view/390 <p>This paper presents an extensive critical review of the light gauge steel-concrete composite<br>column section infilled with Self Compacting Concrete (SCC). The development of Self<br>Compacting Concrete was initiated by Japan, an innovative type of high-performance concrete<br>used in the construction industry. It is also referred to as self-consolidating concrete or<br>rheodynamic concrete or flowing concrete. It has the ability to flow and consolidate under its<br>own weight without any mechanical vibration and even fills the congested reinforcement [1].<br>The potential benefits associated with SCC are passing ability, flowing ability, and segregation<br>resistance. In recent years many research has been carried out with the usage of Self<br>Compacting Concrete as an alternative material for normal concrete [Fig.1].</p> <p>Fig.1. Self Compacting Concrete (SCC)<br>Modern construction widely uses Concrete filled Steel Tubes (CFST) a composite section that<br>enhances the structural capacity of the section and improved stiffness. Traditional concrete<br>filled steel column employed hot rolled sections due to its superior structural performance and<br>ease of construction. Nowadays use of light gauge steel sections is trending extensively<br>because of its easier fabrication, less energy consumption and reduced carbon footprint<br>compared to hot rolled sections[2-4].Nevertheless few attempts have been made on the<br>various cross section dimensions of CFST as shown in [Fig.2] and pinpointed that circular<br>sections are preferred as it marks superior in strength, ductility and post yielding capacity as<br>comparable to rectangular or square sections [5-7,10].<br>State of the Art Report on Light Gauge Steel-Concrete Composite<br>Columns Infilled with Self Compacting Concrete<br>SPAST Abstracts Ganga V,Senthil Selvan S, IGCSTS-1, 2021<br>Fig.2. Cross section of concrete infilled steel columns (CFST)<br>The confinement in the concrete is provided by steel and the concrete in turn delays the local<br>buckling of steel tube resulting in the improved load carrying capacity [6] and represented with<br>failure modes. [Fig. 3]<br>Fig 3. Schematic failure modes of steel, concrete and CFST columns<br>This paper outlines the research work carried on the structural behaviour of composite<br>columns with infills subjected to various loadings and analyzed experimentally and<br>numerically. The ultimate carrying capacity of square and circular columns remains same for<br>normal concrete infilled CFST and SCC infilled CFST [22]. Codes for designing differ<br>according to their philosophies and approaches. This review highlights on the specification<br>and material limits for the use of steel and concrete given in the codes for CFST column<br>design. And focusses on prediction of ultimate strength capacity with reference to codal<br>provisions [19,20]. Comparisons are made to predict the ultimate strength of CFST sections<br>using various codes such as American concrete Institute (ACI)[18], Architectural Institute for<br>Japan (AIJ)[21], Eurocode 4[13] and Chinese code (DBJ)[17].<br>Many researchers has made study on CFST stub columns. An attempt was made to study the<br>behaviour of stub columns with the consideration of various parameters such as section types,<br>local compression area ratio and thickness of end plate and concluded that for higher<br>compression area ratio, strength increases with increase in top plate thickness [10]. The<br>slenderness ratio λ is given by 4L/D and 2√3L/D for column with circular and square section<br>respectively. The predicted load carrying capacity of CFST columns infilled high strength SCC<br>with various codes are compared with test results and revealed that Euro code EC4 gives a<br>good agreement with circular section whilst DBJ code [17] and AISC codes are applicable for<br>columns with square shapes. The failure mode of latter columns shown local buckling and<br>former with a shear failure mode [11].<br>Since SCC are liable to shrinkage stresses and efforts have been made by several<br>res