Shubhankar Bhowmick

Optimization of Esterification of Propionic Acid with Ethanol Catalyzed by Solid Acid Catalysts using Response Surface Methodology (RSM): A Kinetic Approach

Abstract The esterification of propionic acid and ethanol using waste material as catalyst is emerging and a new technology. In this section a carbon based solid acid catalyst was prepared in laboratory by sulfonating waste rice husk char using concentrated H2SO4 and was compared with a commercial catalyst Dowex 50Wx8-400. Characterization analysis of the catalyst was performed using scaning electron microscope (SEM), EDEX and FTIR. Various reaction parameters such as effect of temperature, effect of the molar ratio of ethanol to propionic acid and effect of catalyst loading were investigated. Reusability of catalyst was also performed 4 cycles for efficiency of prepared catalyst. The activation energy (Ea) of esterification was found to be 39.782 kJ mol−1 using rice husk catalyst and 65.306 kJ mol–1 for Dowex 50wx8-400 catalyst. Response surface methodology (RSM) was applied to find the optimal operating conditions in order to maximize the ethyl propionate conversion.

Performance of Functionally Graded Exponential Annular Fins of Constant Weight

The present work aims at investigating the performance of exponential annular fins of constant weight made of functionally graded materials (FGM). The work involves com‐ putation of efficiency and effectiveness of such fins and compares the fin performances for different exponential profiles and grading parameters, keeping the weight of the fin constant. The functional grading of thermal conductivity is assumed to be a power func‐ tion of radial co-ordinate which consists of parameters, namely grading parameters, vary‐ ing which different grading combinations can be investigated. Fin material density is assumed to be constant and temperature gradient exists only along the radial direction. The convective coefficient between the fin surface and the environment is also assumed to be constant. A general second-order governing differential equation has been derived for all the profiles and material grading. The efficiency and effectiveness of the annular fin of different geometry and grading combinations have been calculated and plotted and the results reveal the dependence of thermal behavior on geometry and grading parame‐ ter. The effect of variation of grading parameters on fin efficiency and effectiveness is re‐ ported. The results are provided in the form of 2-D graphs, which can be used as design monograms for further use.

Thermal comfort analysis: A case study of LIG housing in Chhattisgarh

The present work reports the evaluation of temperature distribution inside a Low Income Group (LIG) house located in the city of Raipur, Chhattisgarh, using a Agros2D which is multi-platform C++ application capable of higher-order finite element formulation with h, p and hp adaptivity for the solution of differential equations based on the Hermes library. Variation of room air temperature along the length (x) of the house is calculated at different altitudes viz. 0.5m, 1m, 1.5m, 2m, 2.5m, and 3m. 2D model is generated for all the respective altitudes which show the temperature distribution inside the building.

An approximate solution to the stress and deformation states of functionally graded rotating disks

The present work employs variational principle to investigate the stress and deformation states and estimate the limit angular speed of functionally graded high-speed rotating annular disks of constant thickness. Assuming a series approximation following Galerkin’s principle, the solution of the governing equation is obtained. In the present study, elasticity modulus and density of the disk material are taken as power function of radius with the gradient parameter ranging between 0.0 and 1.0. Results obtained from numerical solutions are validated with benchmark results and are found to be in good agreement. The results are reported in dimensional form and presented graphically. The results provide a substantial insight in understanding the behavior of FGM rotating disks with constant thickness and different gradient parameter. Furthermore, the stress and deformation state of the disk at constant angular speed and limit angular speed is investigated to explain the existence of optimum gradient parameters.