Table of Contents - Volume 20 Number 1

Experimental fabrication of functionally graded Aluminum Silicon-carbon nanotubes (AlSi-MWCNT) reinforcement is significantly less, despite substantial theoretical interest. Many studies focused on axially layered functionally graded material because of ease of fabrication. Full advantage of AlSi-MWCNT functionally graded material only is taken when designed to the various shapes. In this research work, functionally graded cylinders were produced with 2wt% MWCNT at the outer surface to provide a complex and wear-resistant surface. The interior surface is soft with AlSi to provide elasticity. FGM1 sample indicates 112% and 11% increase in maximum tensile strength compared to AlSi and AlSi-MWCNT1wt%. FGM1 sample shows a 37% increase in elongation percentage compared to the AlSi-MWCNT1wt% composite. Test samples showing the typical nature of barrelling. FGM1 sample exhibits compressive strength of 237MPa, exceeding by 245% that of AlSi and by 3.5% that of AlSi-MWCNT1wt%. Three samples consider for each test. Hardness value ranges from 65HV at the core to 115HV at the outer surface. Hardness value Exceeds 56% in the outer layer compared to an inner region of FGM2.There is a proper bond between the layers, and the same demonstrate with properties of tensile, compressive, and hardness. OM with porosity, SEM with EDX evaluates to predict structural gradation in FGM cylinder.

Hide Abstract

In order to explore the heat storage properties of phase change paraffin, a calculation model for melting heat storage of phase change paraffin was established based on the equivalent heat capacity method. A finite element software (COMSOL) was used to study the influence of different inclination angles on heat storage properties of phase change paraffin. The results show that the melting process of phase change paraffin is determined by heat conduction and natural convection heat transfer, natural convection heat transfer plays a significant role in the process of heat storage in phase change paraffin. Phase change paraffin exhibits distinct melting heat storage efficiency under different inclination angles. When  changes from -90° to 90°, the melting time of paraffin decreases gradually. When , the melting time of paraffin is the slowest, when , the melting time of paraffin is the fastest, and the melting speed of paraffin is increased by about 8.6 times.

Hide Abstract

Perovskite-silicon tandem solar cells have attracted much attention to photovoltaic community because of their high efficiency via easy fabrication methods and availability of precursor material abundant in nature. The properties of both perovskite and silicon meet ideal solar cell standards such as high light absorption potential, long carrier diffusion length and fast charge separation process. Semi-transparent solar cell with widely tunable band gap of perovskite material is compatible with silicon solar cell for tandem structures. A perovskite-silicon tandem solar cell four terminal configuration optimization was performed through numerical simulation. The optimized four terminal perovskite-silicon tandem solar cell performances was investigated by varying the thickness of top and bottom solar cell absorber layers, defect density of the absorber layer, and temperature. Perovskite-silicon tandem solar cell showed better photovoltaic performance under constant illumination condition. A high performance mechanically attached four terminal (4-T) perovskite-silicon tandem solar cell has total power conversion efficiency (PCE) of 34.88% by optimized parameters through simulation. It has shown 37% efficiency with matched current of 23.71mA/cm². These numerical simulation results are provided the parameter values for further experimental assignment.

Hide Abstract

Many studies have been conducted on Spinel, Garnet, and Hexa-ferrites in single and multi-doped concentrations. This article is an attempt to review the researcher's work on Ca, Ba, and Sr hexaferrite by substituting a variety of various ions such as Al, La, Sn, Zr, Co, Cr, and Ir. This review paper investigates M-type (Ca, Sr, Ba) Hexa-ferrites with a space group of P63/mmc that were synthesized using various techniques and characterized by XRD for crystallographic information, SEM and TEM for surface morphology, VSM for magnetic behaviour, and Vector Network Analyzer (VNA) for microwave absorption properties. Changes in a material's chemical composition affect features such as coercivity, saturation magnetization, and Curie temperature, as well as managing these properties and utilizing these compounds in the field of microwave absorption properties and magnetic field industry.

Hide Abstract

Composite materials, in simple terms, are materials that have a multi-phase system composed of reinforcing materials and matrix materials. Composite materials are divided into two types, namely synthetic composite materials and natural composite materials. Wood is a natural composite material consisting of a reinforcement and a matrix. The wood of the matoa tree (Pometia vinnata) is known for its good mechanical strength. The comparison of compressive mechanical strength in this study was conducted on matoa wood and ironwood tree wood (eusideroxylon zwageri). This was performed as supporting data in the discussion of natural composite materials of matoa tree wood as the foundation for environmentally friendly house piles. FEM (Finite Element Method) is a numerical method that analyzes the compressive strength of retaining walls. In this study, the 2D analysis used to determine the compressive strength of the natural composite material of Matoa tree wood. In this study, Matoa wood and ironwood were analyzed for compressive strength using FEM. In this research, three different finite element numbers are based on the software. The Ansys software is used to simulate compressive strength. The results obtained were matoa wood and ironwood, respectively A1 = 6.07e^(-07) MPa, A2 = 1.11e^(-06) MPa, and A3 = 2.09e^(-06) MPa and B1 = 1.17e ^(-06) MPa, B2 = 2.13e^(-06) MPa, and B3 = 4.02e^(-06) MPa. These results indicated that the resistance to mechanical compression test of ironwood tree was greater than matoa tree. However, when it was seen based on the perspective of the impact on the environment, Matoa tree has environmentally friendly properties that are effective and efficient. This is supported by the nature of the matoa tree which is easy to cultivate and its roots do not damage other plants.

Hide Abstract

Adsorption is considered one of the best methods for the removal of heavy metal ions from an aqueous solution. However, the synthesis of adsorbents with desired selectivity and performance remains a key challenge in the battle of water decontamination. Recently, carbon-based and metal-oxide based nanomaterials have emerged as promising candidates for the adsorption of heavy metals due to their high specific surface area, high aspect ratio, and concentrated pore size distribution. Here, in this work five adsorbents ie. Graphene Oxide (GO), Magnetic Graphene Oxide (MGO), Titanium Dioxide (TiO₂), and their composites GO-TiO₂ and MGO-TiO₂ were synthesized. The prepared samples were characterized via high-resolution imaging, BET-N₂ adsorption-desorption analysis, and spectroscopic techniques. TEM results revealed the nanoscale structures of the synthesized nanomaterials. The approximate sizes of MGO and TiO₂ nanoparticles found under TEM studies were about 24.58 and 35.51 nm respectively. The presence of desired functional groups was very well deciphered by FT-IR spectroscopy. Results of N₂ adsorption-desorption studies revealed that the prepared GO was macro-porous while all other samples were mesoporous. MGO was found to have the highest BET surface area of about 108.375 m²/g. These results indicate that the prepared nanomaterials may serve the purpose of effectively adsorbing the heavy metal ions from an aqueous solution.

Hide Abstract

The optimization of machining parameters in the turning operation of metal matrix composite (MMC) is a crucial aspect in the manufacturing process. In this research work, Taguchi Method of optimization is used to optimize the cutting parameters, which include cutting speed, feed rate, and depth of cut. The experiments are carried out according to Taguchi L9 algorithm. The optimization is based on minimizing the surface roughness. The results show that the cutting speed has the most significant effect on the responses, followed by feed rate and depth of cut. It is observed a good agreement between the predicted and actual results, indicating the effectiveness of the Taguchi method  in optimizing the cutting parameters.

Hide Abstract