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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.


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.


Mukherjee P.K.,Government College of Engineering and Textile Technology , Berhampore
Journal of Molecular Liquids | Year: 2013

A phenomenological Landau-like theory is presented, which describes the isotropic to chiral smectic-C (I-SmC*) phase transition in chiral smectic-C (SmC*) elastomers and polymers. The coupling between elastic strain, SmC* order parameters and polarization is examined and piezoelectric and ferroelectric effects are predicted. While this phase transition is first order in low-molecular-weight SmC* materials, we show here that the order of this transition does not change in SmC* elastomers. The effect of the electric field in SmC* elastomers is examined. The temperature dependence of the anomalous heat capacity and the nonlinear dielectric effect in the isotropic phase above the I-SmC* phase transition in SmC* elastomers are calculated. © 2013 Elsevier B.V.


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.


Halder T.,Government College of Engineering and Textile Technology , Berhampore
Proceedings of 2013 International Conference on Power, Energy and Control, ICPEC 2013 | Year: 2013

The paper advocates a comparative study of HVDC and HVAC power system. The High voltage direct current (HVDC) is preferred technology for sending a chunk of power across long distances with fewer losses. HVDC results in higher efficiency, excellent voltage profile, regulation, economical, lesser conductor, no reactive power compensation, healthy stability and reliability than an equivalently-sized high voltage alternating current (HVAC) system transmitting the same amount of power © 2013 IEEE.


Mukherjee P.K.,Government College of Engineering and Textile Technology , Berhampore
RSC Advances | Year: 2015

Recent experimental studies have shown that the liquid crystal substance plays an important role in determining the structures and the phase transitions of the different rotator phases in binary mixtures of n-alkane and liquid crystals. The mixtures exhibit crystal and four different rotator phases RI, RII, RIII and RV, although the RIII phase is absent in pure alkane. We described these experimental observations within phenomenological theory. The influence of the liquid crystal solute on the rotator phase transitions and the transition temperatures was discussed by varying the coupling between the concentration variable and the order parameters. The theoretical predictions were found to be in good qualitative agreement with the experimental results. This journal is © The Royal Society of Chemistry.


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.


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

We present a mean-field analysis of the phase transitions of ferronematic in lyotropic liquid crystals. The model free energy is written in terms of the orientational order parameter, magnetization and micellar concentration. We find four different phases: (i) isotropic ferrofluid, (ii) isotropic micellar ferrofluid, (iii) lyotropic paranematic and (iv) lyotropic ferronematic. We put special emphasis on the phase transition from isotropic micellar ferrofluid to ferronematic phase. It was observed from the theoretical calculations that the transition from the isotropic micellar ferrofluid to lyotropic ferronematic phase is weakly first order. The temperature and concentration dependence of the magnetic birefringence and Cotton-Mouton constant are calculated. © 2014 Elsevier B.V.


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.


Mukherjee P.K.,Government College of Engineering and Textile Technology , Berhampore
Physics Reports | Year: 2015

Although the rotator phases of the normal alkanes have been studied for the greater part of the century, it is only in the last two decades that the experimental and theoretical investigations of the structures and phase transitions of these systems have been advanced. This review article presents a comprehensive overview until this date of the theoretical developments and experimental studies in this subject. This article discusses the unified picture of the symmetry, structure and types of rotator phases of normal alkanes. This is followed by a discussion of the order parameters involved in the phase transitions. The application of the various theories to the description of the rotator phase transitions are reviewed comprehensively. The basic ideas of Landau theory and renormalization group theory and its applications to study these transitions are discussed. The current status of the study of the rotator phase transitions in the binary mixtures of alkanes including the nanoparticles and liquid crystal is outlined. A survey is given of existing computer simulation studies of the rotator phase transitions of the normal alkanes. A critical assessment of the experimental and theoretical investigations concerning the elastic properties of the rotator phases is made. © 2015 Elsevier B.V.

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