Sumit Sharma; Pramod Kumar; Ajay Kumar Diwakar
Abstract
Nowadays there is a requirement of material that has high thermal conductivity as well as suitable electric insulating properties. Such materials are required in industries where thermal management is desirable but electrical conductivity is not required, such as substrates for electronic components ...
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Nowadays there is a requirement of material that has high thermal conductivity as well as suitable electric insulating properties. Such materials are required in industries where thermal management is desirable but electrical conductivity is not required, such as substrates for electronic components and solar panels. In this study, the multi-scale modeling of epoxy (bisphenol-A) reinforced alumina composite has been performed using BIOVIA Materials Studio and Abaqus. Modeling has been done for varying volume fraction (Vf) of alumina. The properties predicted are the thermal conductivity and Young’s modulus. Heat transfer analysis has been done using Abaqus/Explicit. It was found that the thermal conductivity first increased till Vf = 20% and then decreased. When the concentration of alumina was increased further after Vf = 20%, the orientation of alumina particles changed from being in-plane to random, resulting in a fall in the values of thermal conductivity. In the silicon/insulator plate system, there was found to be an accumulation of heat resulting in a decrease in temperature on the bottom surface of the insulator plate. Thus, more time was taken for the heat to conduct through this system. Whereas, when the heat was transferred through the system of silicon/composite plate, no accumulation of heat in the system was observed.
Himani Uppal; Nijhuma Kayal; Sneha Chawla; S. Swarupa Tripathy; Sonali Gupta; Rajni Singh; Bharti Sharma; Nahar Singh
Abstract
A new hydrothermal approach has been investigated for synthesis of alumina which has been utilized for decontamination of trivalent and hexavalent chromium (Cr) as well as microbes from water. The heat treatment of aluminum nitrate and sucrose forms single phase g-alumina compact of 318 m 2 /g surface ...
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A new hydrothermal approach has been investigated for synthesis of alumina which has been utilized for decontamination of trivalent and hexavalent chromium (Cr) as well as microbes from water. The heat treatment of aluminum nitrate and sucrose forms single phase g-alumina compact of 318 m 2 /g surface area at 1100 °C. The carbon particles present in aluminum nitrate- sucrose system get oxidized as carbon dioxide. The removal efficiency of synthesized alumina has been compared with commercial alumina and studied as a function of pH, time and adsorbent dose. Interestingly, synthesized alumina have better removal efficiency than commercial one. The adsorption data was best fitted to Langmuir isotherm suggesting monolayer adsorption. The adsorption capacity of the proposed material was found to be 11.76 mg g -1 and 11.9 mg g -1 for Cr (III and VI) respectively, which is better than several inorganic materials reported. The proposed alumina also inhibits growth of several bacteria like Bacillus cereus, Bacillus subtilis, Bacillus licheniformis, Staphylococcus aureus, Streptococcus pyogene, Pseudomonas aeruginosa, Klebsiella pneumoniae, Serratia marcescens, Salmonella typhimurium and Proteus hauseri upto 98%. The adsorption experiments were carried out in triplicate to get reproducible results. All experimental data for Cr removal has been reported with 95% confidence level (K=2).
Jitendra Gangwar; Kajal Kumar Dey; Surya Kant Tripathi; Avanish Kumar Srivastava
Abstract
We report the synthesis of nano-scaled alumina of varied dimensions through a novel optimized processing of aluminum nitrate. The X-ray diffractometry confirmed the formation of X- and γ- phases of alumina particles in the nano region, depending on the annealing conditions during processing. Subsequently, ...
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We report the synthesis of nano-scaled alumina of varied dimensions through a novel optimized processing of aluminum nitrate. The X-ray diffractometry confirmed the formation of X- and γ- phases of alumina particles in the nano region, depending on the annealing conditions during processing. Subsequently, a detailed microscopic investigation revealed the morphological alterations and crystallographic information even at lattice scale. The presence of different bonds and band energies were investigated by employing infra-red and photoluminescence spectrometry, respectively. The evolution of fascinating microstructure, phase formations and optical bands has been presented and discussed to elucidate the systematic evolution of different crystalline phases (α and γ) from an amorphous alumina with increased annealing temperature.
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