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Associate Professor of Electrical Engineering Department
Electrical Engineering Department Netaji Subhash Engineering College, Technocity Garia, Kolkata – 700 152
Subrata Biswas (SM’12) was born in Kolkata, India in 1978. He received the B.E. degree from Burdwan University, Burdwan, India in 2002 and the M.E.E and PhD (Engineering) degree from Jadavpur University, Kolkata, India in 2006 and 2017 respectively. Currently, he is an Associate Professor in the Electrical Engineering Department, Netaji Subhash Engineering College, Kolkata, India.He has published more than 10 research papers. His research includes the data acquisition and advanced signal processing technique in power system & high voltage Engineering and Partial discharge diagnostics.
Data acquisition and advanced signal processing technique in power system & high voltage Engineering and Partial discharge diagnostics.
This project primarily involves the measurement of partial discharge signals from test object and pattern recognition of those signals so as to determine the type of defect and the condition of the insulation. These days dry type systems are taking over most of the high voltage systems including power sectors. The most important aspect related to dry type system is the problem of partial discharge, as it degrades and reduces the insulation life.
D.K. Chattoraj, P.K. Mahapatra, and S.C. Biswas
Colloids and Surfaces A: Physicochemical and Engineering Aspects, ISSN: 09277757, Volume: 149, Issue: 1-3, Pages: 65-80, Published: 15 April 1999 Elsevier BV
D.K. Chattoraj, S.C. Biswas, P.K. Mahapatra, and Shampa Chatterjee
Biophysical Chemistry, ISSN: 03014622, Pages: 9-25, Published: 8 March 1999 Elsevier BV
Journal of Surface Science and Technology, ISSN: 09701893, Issue: 1--4, Pages: 78-92, Published: 1998
S.C. Biswas and D.K. Chattoraj
Journal of Colloid and Interface Science, ISSN: 00219797, Volume: 205, Pages: 12-20, Published: 1 September 1998 Elsevier BV
The kinetics of adsorption of cationic surfactants (CTAB, MTAB and DTAB) at silica surface has been studied at various values of bulk surfactant concentration (Ct<INF POS="STACK">2), pH, ionic strength, and temperature and in presence of different electrolytes and urea. The adsorption process has been found to follow a two-step first-order kinetic rate equation with two different rate constants k1 and k2. From the variation of k1 and k2 with temperature, values of energies of activation Ea1 and Ea2 for both the kinetic steps have been evaluated. The corresponding values of enthalpies of activation (DeltaH<INF POS="STACK">1# and DeltaH<INF POS="STACK">2#), entropies of activation (DeltaS<INF POS="STACK">1# and DeltaS<INF POS="STACK">2#) have been evaluated using Eyring's equation for absolute reaction rate. It has been found that for both the kinetic steps, DeltaH<INF POS="STACK">1# < TavDeltaS<INF POS="STACK">1# and DeltaH<INF POS="STACK">2# < TavDeltaS<INF POS="STACK">2#, which means that activation reaction is largely entropy controlled. Again, for both kinetic steps, DeltaH# varies linearly with TavDeltaS#, and DeltaG<INF POS="STACK">1# and DeltaG<INF POS="STACK">2# vary between 70 and 88 kJ/mole of surfactant, respectively. Thus there is a entropy-enthalpy compensation effect in the adsorption process. Copyright 1998 Academic Press.
Journal of Surface Science and Technology, ISSN: 09701893, Issue: 2--4, Pages: 1-14, Published: 1997
S. C. Biswas and D. K Chattoraj
Langmuir, ISSN: 07437463, Pages: 4512-4519, Published: 20 August 1997 American Chemical Society (ACS)
By use of the equilibrium dialysis technique, the extent of binding (Γ21) of cationic surfactants cetyltrimethylammonium bromide (CTAB), myristyltrimethylammonium bromide (MTAB), and dodecyltrimethylammonium bromide (DTAB) with dextrin and carboxymethyl cellulose (CMC) respectively have been measured as a function of surfactant concentration (C2), pH, ionic strength, and temperature. Γ21 increases with increase of C2 until it reaches a maximum value, Γ2m. On further increase of C2, Γ21 in all cases sharply decreases linearly with C2 until its value becomes zero at the azeotropic state when surfactant concentration is considerably higher than the bulk critical micelle concentration (cmc). With further increase of C2, Γ21 becomes negative and its magnitude increases with further increase of C2 without reaching a limiting value. Using the concept of the Gibbs surface excess, it has been shown that binding of both surfactant and water to polysaccharide is responsible for the observed overall shape of the bind...
S. C. Biswas and D. K. Chattoraj
Langmuir, ISSN: 07437463, Pages: 4505-4511, Published: 20 August 1997 American Chemical Society (ACS)
The extent of adsorption (Γ21) of cetyltrimethylammonium bromide (CTAB), myristyltrimethylammonium bromide (MTAB), and dodecyltrimethylammonium bromide (DTAB) from aqueous solution onto a cellulose−water interface has been measured analytically in a wide range of surfactant concentrations below and above the critical micelle concentration (cmc) at different physicochemical conditions and in the presence of different electrolytes and urea. Γ21 is found to increase with increase of bulk surfactant concentration C2 until it reaches a maximum value Γ2m when C2 reaches a critical value, C2m. With further increase of C2 beyond C2m, Γ21 decreases from Γ2m and becomes zero with attainment of surface azeotropic state at a surfactant concentration C2azeo. For C2 > C2azeo, values of Γ21 are negative due to the excess hydration of cellulose fibril and desorption of surfactant micelles from the surface to the bulk phase. The value of Γ2m depends upon the different physicochemical conditions and presence of different e...