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Saha S.S.,Government College of Engineering and Textile Technology , Berhampore
International Journal of Hydrogen Energy | Year: 2011

The dc voltage generated from fuel cell is low in magnitude, unregulated and load dependent. Hence, it is required to be regulated and boosted by high performance dc-dc converter. In this paper, a fully soft-switched pulse-width-modulated dc-dc boost converter has been proposed for fuel cell applications. The proposed converter operates at high switching frequency with high efficiency and large power to volume ratio. A laboratory prototype model of the proposed converter has been designed and fabricated for charging a battery bank at 110 V from a fuel cell stack SR-12 of Avista Lab. The experimental results were found in close agreement with the predicted behavior. © 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved. Source


Mukherjee P.K.,Government College of Engineering and Textile Technology , Berhampore
Journal of Molecular Liquids | Year: 2014

The present review represents an attempt towards a unified picture of the direct transition from the isotropic to smectic-A phase. The isotropic to smectic-A phase transition is described in detail, including structure and nature revealed by experiments, molecular models and Landau-de Gennes theory. The wide variety of phenomena including effects of nonmesogenic impurities and electric field, hydrodynamics, fluctuations, and elastic theory of liquid crystalline elastomers is discussed. A brief review on the general information about the isotropic to lamellar phase transition in lyotropic liquid crystals has been given. The various predictions are compared with the available experimental results. Open questions and possible approaches to finding answers are discussed. © 2013 Elsevier B.V. Source


Mukherjee P.K.,Government College of Engineering and Textile Technology , Berhampore
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2013

We use a phenomenological model to find theoretically the temperature dependence of the static dielectric permittivity at the isotropic to smectic-A phase transition. The temperature dependence of the static dielectric permittivity is presented for the isotropic and smectic-A phases of the transition. Eventually, a comparison is made with experimental data available in the isotropic phase above the isotropic to smectic-A phase transition. We finally conclude that the model provides a good description of all known features of the static dielectric permittivity in the isotropic phase above the phase transition. © 2013 Elsevier B.V. Source


Roy Choudhury A.K.,Government College of Engineering and Textile Technology , Berhampore
Textile Progress | Year: 2013

In contrast to non-sustainable, non-renewable fossil-fuel-based conventional chemical processes, so-called green reactions are sustainable, highly-efficient (fewer steps, fewer resources, less waste) and stable under ambient conditions and much more eco-friendly (achieved by the use of non-hazardous solvents and less-hazardous, minimized waste). Theyare assessed by 12 principles established by Anastas and Warner [Green Chemistry: Theory and Practice, Oxford University Press, New York, 1998]. Recently steps have been taken to make textile materials and processing more environmentally friendly (or 'greener'), including fibre production, dyes and auxiliaries, solvents, optimized and efficient processing with recycling of water and chemicals, bio-processing, the elimination of hazardous chemicals and the recycling of textile materials, and whilst it is acknowledged that mechanical aspects of textile processing also contribute to achievement of sustainability, this review focuses on the chemistry deployed. © 2013 The Textile Institute. Source


Mukherjee P.K.,Government College of Engineering and Textile Technology , Berhampore
RSC Advances | Year: 2013

A phenomenological theory is presented to describe the isotropic micellar to lamellar (I-LD) phase transition in lyotropic liquid crystals. The model free energy is written in terms of the coupled order parameters including the micellar concentration. The conditions for the I-LD phase transition and the stability conditions of the lamellar phase are calculated. On the basis of this model, it is argued that the I-LD phase transition is always first order. The theoretical predictions are found to be in good qualitative agreement with available experimental results. © The Royal Society of Chemistry 2013. Source

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