Ashis Mallick

Inverse Prediction and Application of Homotopy Perturbation Method for Efficient Design of an Annular Fin with Variable Thermal Conductivity and Heat Generation

AbstractIn the present work, various thermal parameters of an annular fin subjected to thermal loading are inversely estimated using differential evolution (DE) method. In order to obtain the temperature field, the second order nonlinear differential equation for heat transfer with variable thermal conductivity and internal heat generation is solved using Homotopy Perturbation Method (HPM). Classical thermo-elasticity approach coupled with an HPM solution for temperature field is employed for the forward solution of thermal stresses. It is interesting that the internal heat generation does not affect the radial stresses, while the temperature field and the tangential stresses are influenced by the heat generation parameters. As the tangential stresses are mainly responsible for mechanical failure due to thermal loading in an annular fin, the unknown thermal parameters are inversely estimated from a prescribed tangential stress field. The reconstructed stress fields obtained from the inverse parameters are...

Strength of Mg–3%Al alloy in presence of graphene nano-platelets as reinforcement

ABSTRACT Bulk Mg–3%Al alloy-based nanocomposites containing graphene nano-platelets (GNPs) were synthesised using the powder metallurgy technique incorporating energy efficient hybrid microwave sintering and hot extrusion. GNPs in amounts of 0.1, 0.3 and 0.5 wt-% were investigated as reinforcements. Microstructural characterisation accomplished using optical, scanning and transmission electron microscopy revealed the presence of minimal porosity (<1%), a uniform distribution of GNPs in the matrix and a reduced grain size as a result of the presence of GNPs. The results of mechanical property characterisation revealed an overall improvement in micro-hardness and compressive response, due to the presence of GNPs, with best results exhibited by the Mg–3Al/0.3% GNPs composite. The ductility under compressive loading for composite samples remained higher than 20%.

Processing of PMMA nanocomposites containing biocompatible GO and TiO2 nanoparticles

ABSTRACT The present study addresses the synthesis and characterization of polymethyl methacrylate (PMMA)/graphene oxide (GO) and PMMA/GO + TiO2 nanocomposites for potential application as dental materials. PMMA/0.0025 wt% GO and PMMA/0.0025 wt%GO + 1 wt% TiO2 were processed using twin-screw extrusion including melt compounding. The mechanical, thermal, and microstructural behaviors of nanocomposites were determined and compared with pure PMMA. The results of this work revealed that PMMA nanocomposites are potential candidates as dental materials.

Stresses in radiative annular fin under thermal loading and its inverse modeling using sine cosine algorithm (SCA)

Abstract This work presents a novel mathematical model for the analysis of thermal stresses in a radiative annular fin with temperature-dependent thermal conductivity and radiative parameter. An approximate analytical solution for thermal stresses is derived using a homotopy perturbation method (HPM)-based closed-form solution of steady-state nonlinear heat transfer equation, coupled with classical elasticity theory. The effect of thermal parameters on the temperature field and the thermal stress fields are discussed. The various thermal parameters, such as a parameter describing the temperature-dependent thermal conductivity, coefficient of thermal expansion, coefficient of radiative parameter, and the variable radiative parameter, are inversely estimated for a given stress field. For inverse modeling, a population-based sine cosine algorithm (SCA) was employed to estimate the thermal parameters. The inverse modeling is verified by using the estimated thermal parameters in the closed-form solution of stress field. The reconstructed stress fields obtained from the inversely estimated parameters are then compared with the reference stress field. Results show a very good agreement between the reference stress field and the inversely estimated stress fields.

Inverse estimation of variable thermal parameters in a functionally graded annular fin using dragon fly optimization

ABSTRACT This paper presents an inverse study of heat transfer of a conductive, convective and radiative annular fin made of a functionally graded material. Three major parameters such as conductive–convective parameter, conductive–radiative parameter and the parameter describing the variation of thermal conductivity are inversely estimated from a specified temperature field. The forward solution of temperature field is obtained from the closed form solution of nonlinear heat transfer equation using Homotopy perturbation method (HPM). A dragonfly algorithm that simulates the swarming behaviour of dragonflies, as analogous, is employed in finding out the inverse parameters. The temperature values of the forward solution are used as input data for the inverse analysis. The inverse parameters are then estimated iteratively by minimizing the objective function until the guessed temperature field approximately satisfies the preassigned temperature field of the forward solution. The inverse simulation following HPM-based forward solution converges faster than ordinary differential equation-based forward solution. The reconstructed temperature fields obtained from the various combination of inverse parameters give good agreement (∼1% error) with the desired temperature field. Thus, the presented inverse model provides an opportunity to the fin designer for selecting the several feasible combinations of thermal parameters suggesting the material design that result in a prescribed temperature field.

Current scenario of biodiesel development in India: prospects and challenges

ABSTRACT For a developing nation like India, the current energy portfolio is dominated by fossil fuels such as oil, coal, and petroleum products. Due to the rapid depletion and limited available resources, the price of fossil fuel increases. Also, fossil fuel induces climate change, environmental pollution, and rising global temperature. There is urgent need to shift from conventional energy to renewable energy source for sustainable and economic growth and to enhance a country’s energy security. Biofuel offers an attractive source of energy for the substitution of fossil fuels, and looking at the huge demand for diesel in all sectors of the economy, the biodiesel is being viewed as the best substitute for diesel. The other advantage for biofuel promotion in India is climate change mitigation through reduced greenhouse gas (GHG) emission. This article provides the current status of biodiesel development in India and discusses the role played by the centre and state government in promoting second-generation feedstock (nonedible seeds) and third-generation feedstock (algae) for biodiesel production.

Ultrasonic-assisted production of biodiesel from Manilkara Zapota (L.) seed oil

ABSTRACT This paper investigates a novel method for the intensification of biodiesel production via alkali-catalyzed transesterification of an underutilized feedstock, Manilkara zapota (L.) seed oil (MZO) using ultrasonic energy. The effects of the oil to methanol molar ratio (1:5–1:7), catalyst concentration (0.5–1.5 wt%), and reaction temperature (30–50°C) have been investigated using an ultrasonic frequency of 20 kHz and an ultrasonic power of 50 Watt. Optimal conversion of 97% was achieved in 20 min in an ultrasonic cavitation reactor with 1:6 molar ratio of oil to methanol, 1 wt% of catalyst, and 50°C of reaction temperature. The transesterification process is repeated with a conventional (mechanical stirring) method at optimum conditions (1:6 molar ratio, 1 wt% catalyst concentration, and 50°C reaction temperature). Biodiesel obtained from the ultrasonic method and the conventional method was then compared for their percentage yield and physicochemical properties. Ultrasonic transesterification process gave a maximum yield of 97% by weight of M. zapota biodiesel along with enhanced physiochemical characteristics. Therefore, it is concluded that ultrasonic process is the most effective method for converting MZO into biodiesel. The major properties of M. zapota oil methyl ester (MZME) met the requirements of EN 14214 biodiesel standard and therefore M. zapota (L.) seed oil can be a possible substitute to petro diesel.