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Search Results: 1 - 10 of 145468 matches for " Abhijit K. Das "
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Synthesis, Characterization and Performance Evaluation of an Advanced Solid Electrolyte and Air Cathode for Rechargeable Lithium-Air Batteries  [PDF]
Susanta K. Das, Jianfang Chai, Salma Rahman, Abhijit Sarkar
Journal of Materials Science and Chemical Engineering (MSCE) , 2016, DOI: 10.4236/msce.2016.41012
Abstract:

Synthesis and characterization of a tri-layered solid electrolyte and oxygen permeable solid air cathode for lithium-air battery cells were carried out in this investigation. Detailed fabrication procedures for solid electrolyte, air cathode and real-world lithium-air battery cell are described. Materials characterizations were performed through FTIR and TGA measurement. Based on the experimental four-probe conductivity measurement, it was found that the tri-layered solid electrolyte has a very high conductivity at room temperature, 23C, and it can be reached up to 6 times higher at 100C. Fabrication of real-world lithium-air button cells was performed using the synthesized tri-layered solid electrolyte, an oxygen permeable air cathode, and a metallic lithium anode. The lithium-air button cells were tested under dry air with 0.1 mA - 0.2 mA discharge/ charge current at elevated temperatures. Experimental results showed that the lithium-air cell performance is very sensitive to the oxygen concentration in the air cathode. The experimental results also revealed that the cell resistance was very large at room temperature but decreased rapidly with increasing temperatures. It was found that the cell resistance was the prime cause to show any significant discharge capacity at room temperature. Experimental results suggested that the lack of robust interfacial contact among solid electrolyte, air cathode and lithium metal anode were the primary factors for the cell’s high internal resistances. It was also found that once the cell internal resistance issues were resolved, the discharge curve of the battery cell was much smoother and the cell was able to discharge at above 2.0 V for up to 40 hours. It indicated that in order to have better performing lithium-air battery cell, interfacial contact resistances issue must have to be resolved very efficiently.

Anoxybacillus suryakundensis sp. nov, a Moderately Thermophilic, Alkalitolerant Bacterium Isolated from Hot Spring at Jharkhand, India
Kamal Deep, Abhijit Poddar, Subrata K. Das
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0085493
Abstract: Four closely related facultative anaerobe, moderately thermophilic, Gram positive rods (JS1T, JS5, JS11, and JS15) were isolated from sediment samples from a hot spring at Suryakund, Jharkhand, India. Colonies were pale yellow, rough surface with uneven edges on TSA after 72 h incubation. Heterotrophic growth was observed at 40-60°C and pH 5.5-11.5; optimum growth occurred at 55°C and pH 7.5. 16S rRNA gene sequence analysis revealed the strains belong to genus Anoxybacillus. DNA-DNA homology values among strains were above 70% and showed distinct ERIC and REP PCR profile. On the basis of morphology and biochemical characteristics, strain JS1T was studied further. Strain JS1T showed 99.30% sequence similarity with A. flavithermus subsp. yunnanensis, 99.23% with A. mongoliensis, 99.16% with A. eryuanensis, 98.74% with A. flavithermus subsp. flavithermus, 98.54% with A. tengchongensis, 98.51% with A. pushchinoensis, 97.91% with A. thermarum, 97.82% with A. kaynarcensis, 97.77% with A. ayderensis and A. kamchatkensis, 97.63% with A. salavatliensis, 97.55% with A. kestanbolensis, 97.48% with A. contaminans, 97.27% with A. gonensis and 97.17% with A. voinovskiensis. In 16S rRNA secondary structure based phylogenetic comparison, strain JS1T was clustered with Anoxybacillus eryuanensis, A. mongoliensis, and A. flavithermus subsp. yunnanensis and showed 15 species specific base substitutions with maximum variability in helix 6. Moreover, DNA-DNA relatedness between JS1T and the closely related type strains were well below 70%. The DNA G+C content was 42.1 mol%. The major fatty acids were C15:0 iso, C16:0 iso and C17:0iso. The polar lipids were a phosphatidylgylycerol, a diphosphatidylglycerol, a phosphatidylethnolamine, a phosphatidylcholine, a phosphatidyl monomethylethanolamine and four unknown lipids. Based on polyphasic approach, strain JS1T represent a novel species of the genus Anoxybacillus for which Anoxybacillus suryakundensis sp. nov. is proposed. The type strain is JS1T (= DSM 27374T = LMG 27616T =JCM19211T).
Millimeterwave Spectral Studies of Propynal (HCCCHO) Produced by DC Glow Discharge and Ab Initio DFT Calculation
A. I. Jaman,Rangana Bhattacharya,Debasish Mandal,Abhijit K. Das
Journal of Atomic, Molecular, and Optical Physics , 2011, DOI: 10.1155/2011/439019
Abstract: The ground-state (=0) millimeterwave rotational spectrum of propynal (HCCCHO) produced by a DC glow discharge through a low-pressure (~10–20 mTorr) flow of propargyl alcohol (HCCCH2OH) vapor has been observed in the frequency region: 36.0–94.0 GHz. Measured rotational transition frequencies along with the previously reported microwave and millimeterwave transitions were fitted to a standard asymmetric-top Hamiltonian to determine an improved set of rotational and centrifugal distortion constant. Detailed DFT calculations were also carried out with various functional and basis sets to evaluate the spectroscopic constants, dipole moment, and various structural parameters of propynal and compared with the corresponding experimental values.
Millimeterwave Spectral Studies of Propynal (HCCCHO) Produced by DC Glow Discharge and Ab Initio DFT Calculation
A. I. Jaman,Rangana Bhattacharya,Debasish Mandal,Abhijit K. Das
Journal of Atomic and Molecular Physics , 2011, DOI: 10.1155/2011/439019
Abstract: The ground-state ( ) millimeterwave rotational spectrum of propynal (HCCCHO) produced by a DC glow discharge through a low-pressure (~10–20?mTorr) flow of propargyl alcohol (HCCCH2OH) vapor has been observed in the frequency region: 36.0–94.0?GHz. Measured rotational transition frequencies along with the previously reported microwave and millimeterwave transitions were fitted to a standard asymmetric-top Hamiltonian to determine an improved set of rotational and centrifugal distortion constant. Detailed DFT calculations were also carried out with various functional and basis sets to evaluate the spectroscopic constants, dipole moment, and various structural parameters of propynal and compared with the corresponding experimental values. 1. Introduction Propynal (HCCCHO) also known as propiolic aldehyde has been found in interstellar molecular clouds TMC-1 and Sgr B2(N-LMH) [1–3]. In 1955 Howe and Goldstein [4] reported the and microwave transitions of the most abundant isotopic species of propynal. They have determined the dipole moment of the molecule to be D. Later on, Costain and Morton [5] determined the rotational constants , , and ( ) for the parent as well as various isotopic species and were able to determine an accurate substitution structure. Winnewisser [6] has extended the analysis of the ground state of propynal to the millimeterwave region (95.0–200.0?GHz) which has yielded a set of ground state rotational and centrifugal distortion constants. Reference [6] includes a set of predicted -type R-branch frequencies from 37.0 to 94.0?GHz covering to transitions which are of prime importance to radio astronomers for conducting search for this molecule in the interstellar space. Infrared-microwave double-resonance spectroscopic study of propynal using a Zeeman tuned He-Xe laser as the infrared source was conducted by Takami and Shimoda [7] to determine the rotational constants of the excited vibrational state. Later on, Jones [8] has reported the rotational constants of propynal in the ground as well as several excited state combination and hot bands using a CO2 laser as the infrared source. In all the previous works propynal was either procured commercially or prepared chemically. Production of new molecules, molecular ions, and radicals by applying a DC glow discharge through a low-pressure flow of gas or a mixture of gases inside an absorption cell has proved to be an efficient and useful technique [9]. Recently, Jaman [10] has reported an analysis of the millimeterwave rotational spectra of propyne (CH3CCH) produced by a DC glow discharge
Fluctuations and correlations of conserved charges in an excluded volume hadron resonance gas model
Abhijit Bhattacharyya,Supriya Das,Sanjay K. Ghosh,Rajarshi Ray,Subhasis Samanta
Physics , 2013, DOI: 10.1103/PhysRevC.90.034909
Abstract: We present temperature ($T$) and baryonic chemical potential ($\mu_B$) dependence of higher order fluctuations and correlation between conserved charges in Excluded Volume Hadron Resonance Gas (EVHRG) model. Products of moments, such as ratio of variance to mean ($\sigma^2/M)$, product of skewness and standard deviation ($S\sigma$), product of kurtosis and variance ($\kappa\sigma^2$), for net-proton, net-kaon and net-charge have been evaluated on the phenomenologically determined freeze-out curve. Further, products of moments for net-proton and net-charge have been compared with the experimental data measured by STAR experiment. The dependence of the model result on the hadronic radius parameter has also been discussed.
Net Charge Fluctuations as a signal of QGP from Polyakov-Nambu-Jona-Lasinio model
Abhijit Bhattacharyya,Supriya Das,Sanjay K. Ghosh,Sibaji Raha,Rajarshi Ray,Kinkar Saha,Sudipa Upadhaya
Physics , 2012,
Abstract: We report the first model study of the net charge fluctuations in terms of D-measure within the framework of the Polyakov-Nambu-Jona-Lasinio model. Net charge fluctuation is estimated from the charge susceptibility evaluated using PNJL model. A parameterization of the freeze-out curve has been used to obtain D as a function of sqrt(s). We have discussed our results vis-a-vis recent experimental findings from ALICE collaboration.
An augmented space recursion study of the electronic structure of rough epitaxial overlayers
Biplab Sanyal,Parthapratim Biswas,Abhijit Mookerjee,Hemant G. Salunke,G. P. Das,A. K. Bhattacharya
Physics , 1999, DOI: 10.1088/0953-8984/10/26/005
Abstract: In this communication we propose the use of the Augmented Space Recursion as an ideal methodology for the study of electronic and magnetic structures of rough surfaces, interfaces and overlayers. The method can take into account roughness, short-ranged clustering effects, surface dilatation and interdiffusion. We illustrate our method by an application of Fe overlayer on Ag (100) surface.
Identification of Preferable Distributed Generators Locations for Congestion Relief in Multi-Bus Power Network  [PDF]
Barnali K. Sarkar, Abhijit Chakrabarti, Abhinandan De
Energy and Power Engineering (EPE) , 2014, DOI: 10.4236/epe.2014.67015
Abstract: Installation of Distributed Generator (DG) is a well accepted method to improve power system operation from the point of reducing congestion and improving voltage profiles. For best results, Distributed Generators should be placed at strategic locations to exploit maximum benefits out of them. The (N-1) contingency criterion has been taken into account in this work. Most congested lines of the grids are ranked by congestion Index and considered to study the impact of DG penetration on congestion. The present paper proposes contribution factors of Distributed Generators for the placement of DG to keep the line flow within the capacity of each transmission line of the network. The results obtained from IEEE 30-bus test system indicate that the proposed methods are capable of identifying desirable DG location and its maximum allowable size. The influence of DG on bus voltage profile has also been demonstrated in this paper.
Relationship of glucose-6-phosphate dehydrogenase with structural development and growth of human fetal cornea
Sen Abhijit,Mukherjee K
Indian Journal of Ophthalmology , 1983,
Abstract:
Relationship of glucose-6-phosphate dehydrogenase with structural development and growth of human foetal cornea
Sen Abhijit,Mukherjee K
Indian Journal of Ophthalmology , 1984,
Abstract:
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