Dinhata College

Koch Bihār, India

Dinhata College

Koch Bihār, India
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Ghosh M.K.,North Bengal University | Haldar P.K.,Dinhata College | Manna S.K.,Dinhata College | Mukhopadhyay A.,North Bengal University | Singh G.,State University of New York at Fredonia
Nuclear Physics A | Year: 2011

We have investigated the presence of ring and/or jet-like structures in the angular emission of secondary charged mesons (shower tracks) coming out of 16O-Ag/Br and 32S-Ag/Br interactions, each at an incident momentum of 200 AGeV/c. Nuclear photographic emulsion technique has been used to collect the experimental data. The experimental results have been compared with the results simulated by Monte Carlo method. The analysis indicates presence of ring and jet-like structures in the experimental data beyond statistical noise. This kind of jet structure is expected to give rise to a strong two-dimensional (2d) intermittency. The self-affine behaviour of 2d scaled factorial moments (SFM) has therefore been investigated and the strength of 2d intermittency has been determined. For each set of data the 2d results have been compared with the respective one-dimensional (1d) intermittency results. © 2010 Elsevier B.V.


Biswas O.,University of Calcutta | Ghosh R.,University of Lucknow | Paruya D.K.,University of Calcutta | Mukherjee B.,University of Calcutta | And 2 more authors.
Quaternary Science Reviews | Year: 2016

While documenting the vegetation response to climatic changes in mountains, the use of grass phytolith data relies on the ability of phytolith assemblages or indices to differentiate the elevationally stratified vegetation zones. To infer the potential and limitations of grass phytolith assemblages and indices to reconstruct vegetation vis-à-vis climate in the Himalayan mountain regions, we analyzed phytolith assemblages from 66 dominant grasses and 153 surface soils from four different forest types along the c. 130-4000 m a.s.l. elevation gradients in the Darjeeling and Arunachal Himalayas. Grass short cell phytolith assemblages from modern grasses show significant variability with rising elevation. To test the reliability of the above observation, phytoliths from the soil samples were subjected to linear discriminant analysis (DA). DA classified 85.3% and 92.3% of the sites to their correct forest zones in the Darjeeling and Arunachal Himalayas respectively. Relative abundance of bilobate, cross, short saddle, plateau saddle, rondel and trapeziform types allow discrimination of the phytolith assemblage along the elevation gradient. Canonical correspondence analysis (CCA) on the soil phytolith data further revealed their relationships with the climatic variables. Temperature and evapotranspiration were found to be the most influential for differential distribution of grass phytolith assemblages with rising elevation in the eastern Himalayas. We also tested the reliability of phytolith indices (Ic, Iph and Fs) for tracing the dominance of different grass subfamilies in the eastern Himalayas. Ic proved to be most reliable in discriminating C3/C4 grass along the elevation gradient while Iph and Fs proved to be less reliable. We observed that in the monsoon dominated eastern Himalayas, a little adjustment in Ic index may enhance the accuracy of interpretations. In future studies more precise identification of phytolith sub-types from additional sites in the eastern Himalayas may further improve our interpretations related to past climate condition. © 2016 Elsevier Ltd.


Haldar P.K.,Jadavpur University | Manna S.K.,Jadavpur University | Saha P.,Jadavpur University | Ghosh D.,Dinhata College
Indian Journal of Pure and Applied Physics | Year: 2012

The angular sub-structures of particle produced within dense and dilute groups along the rapidity axis in 24Mg induced interaction of Ag/Br nuclei in an emulsion detector at 4.5 A GeV/c have been investigated. The experimental results have been compared with the results simulated by Monte Carlo method. Non-statistical jet-like sub-structures have been found in the data. However, when the parameter S 2 is used in the analysis there seems to be definite jet-structure for the dilute groups which cannot be accounted for independent emission model (MC). The average behaviour of the S parameters strongly favours the presence of jet-like sub-structures.


Das D.,Dinhata College | Messaadi A.,Tunis el Manar University | Dhouibi N.,Tunis el Manar University | Ouerfelli N.,Tunis el Manar University | Hamzaoui A.H.,Center National des Recherche en science des Materiaux
Physics and Chemistry of Liquids | Year: 2013

Calculation of excess properties in N,N-dimethylacetamide + water binary mixtures at (298.15, 308.15 and 318.15) K from experimental density, viscosity and sound velocity values were presented in previous work. Applications of these experimental values to test different correlation equations as well as their corresponding relative functions were also reported. Considering the quasi-equality between the Arrhenius activation energy Ea and the enthalpy of activation of viscous flow ΔH*, here we can define partial molar activation energy Ea 1 and Ea 2 for N,N-dimethylacetamide and water respectively along with their individual contribution separately. Correlation between the two Arrhenius parameters of viscosity in all the domains of composition shows the existence of two main distinct behaviours separated by a stabilised structure in a short range of mole fraction in N,N-dimethylacetamide from 0.2 to 0.3. We add that correlation reveals interesting Arrhenius temperature which is closely related to the vapourisation temperature in the liquid vapour equilibrium. © 2013 Taylor and Francis Group, LLC.


Das D.,Dinhata College | Barhoumi Z.,Tunis el Manar University | Dhouibi N.,Tunis el Manar University | Sanhoury M.A.M.K.,CNRS Coordination Chemistry | Ouerfelli N.,Tunis el Manar University
Physics and Chemistry of Liquids | Year: 2012

Excess molar volumes and viscosity deviations in N,N-dimethylacetamide + dimethylformamide binary mixtures at 298.15, 308.15 and 318.15 K were calculated from experimental density and viscosity data presented in the previous work. Here these experimental values were used to test the applicability of the correlative reduced Redlich-Kister equation and the recently proposed Herráez equation. Their correlation ability at different temperatures, and the use of different number of parameters, is discussed for the case of limited experimental data. These relative functions are important to reduce the effect of temperature and, consequently, to reveal the effects of different types of interactions. Limiting excess partial molar volumes at infinite dilution were deduced from different methods, parameters of molar Gibbs energy of activation of viscous flow against compositions were investigated. The results of these observations have been interpreted in terms of structural effects of the solvents. 1H-NMR studies of these mixtures are also reported. © 2012 Copyright Taylor and Francis Group, LLC.


Das D.,Dinhata College | Barhoumi Z.,Tunis el Manar University | Ouerfelli N.,Tunis el Manar University
Physics and Chemistry of Liquids | Year: 2012

Knowledge and prediction of physicochemical properties of binary mixtures is of great importance for understanding intermolecular interactions. The literature shows that most such systems exhibit non-linear behaviour. Excess molar volumes, viscosity deviations and isentropic compressibility changes in N,N-dimethylacetamide + 2-methoxyethanol binary mixtures at 298.15, 308.15 and 318.15 K were calculated from experimental density, viscosity and sound velocity data presented in previous work. Here these experimental values were used to test the applicability of the correlative reduced Redlich-Kister equation and the recently proposed Herráez equation as well as their corresponding relative functions. Their correlation ability at different temperatures, and the use of different numbers of parameters, is discussed for the case of limited experimental data. These relative functions are important to reduce the effect of temperature and, consequently, to reveal the effects of different types of interactions. Limiting excess partial molar volume at infinite dilution were deduced from different methods, activation parameters and partial molar Gibbs energy of activation of viscous flow against compositions were investigated. The results of these observations have been interpreted in terms of structural effects of the solvents. In this frame, a correlating equation is recently proposed by Belda and in order to assess the validity of the proposed equation, it has also been applied to the present system for molar volume properties. © 2012 Copyright Taylor and Francis Group, LLC.


Das D.,Dinhata College | Messaadi A.,Campus University | Barhoumi Z.,Campus University | Ouerfelli N.,Campus University | Ouerfelli N.,Tunis el Manar University
Journal of Solution Chemistry | Year: 2012

Excess molar volumes, viscosity deviations, and isentropic compressibility changes in N,N-dimethylacetamide + water binary mixtures at (298.15, 308.15 and 318.15) K were calculated from experimental density, viscosity and sound velocity results presented in previous work. Here these experimental values were used to test the applicability of the correlative reduced Redlich-Kister equation and the recently proposed Herráez equation, as well as their corresponding relative functions. Their correlation ability at different temperatures, and the use of different numbers of parameters, are discussed for the case of limited experimental data. The relative functions are important to reduce the effect of temperature and, consequently, to reveal the effects of different types of interactions. Values of the limiting excess partial molar volume at infinite dilution were deduced using different methods. Also, the activation parameters and partial molar Gibbs energy of activation of viscous flow were analyzed as functions of composition. Correlation between the two Arrhenius parameters of viscosity in all composition domains show the existence of two distinct behaviors, separated by a stabilized structure over a short range of mole fractions from (0.2 to 0.3) in N,N-dimethylacetamide. In this regard, a correlation equation recently proposed by Belda has also been applied to the present system for deriving molar volume properties, in order to assess the validity of the proposed equation,. © Springer Science+Business Media, LLC 2012.


Excess molar volumes and viscosity deviations in binary mixtures of N,N-dimethylacetamide with formamide at (298.15, 308.15 and 318.15) K were calculated from experimental density and viscosity data presented in previous work. The density and viscosity data as well as their corresponding derived functions were used to test the applicability of two correlative equations: the reduced Redlich-Kister equation and the recently proposed Herráez equation. Their correlation abilities at different temperatures, and the use of different numbers of parameters, are discussed for the case of limiting experimental data. These relative functions are important to reduce the effect of temperature and, consequently, to reveal the effects of different types of interactions. Correlation between the two Arrhenius parameters of viscosity over the composition domains shows the existence of two distinct behaviors. © Springer Science+Business Media, LLC 2012.


Haldar P.K.,Dinhata College | Manna S.K.,Dinhata College
Canadian Journal of Physics | Year: 2011

The analysis of ring-like and jet-like events in 16O-Ag/Br interactions at 60 A GeV is performed using the methods of factorial correlators and oscillatory multiplicity moments. The investigation reveals that the correlators increase with a decrease of the size of bin separation interval, following the power law, and suggest the presence of the intermittent nature of the dynamical fluctuations measured. The analysis shows the signal of the intermittency to be stronger in the ring-like events. However, both the ring-like and jet-like events are found to be consistent with the α-model predictions. The oscillatory moments are found to follow a different behavior in ring-like events and jet-like events. In most cases, the simulation fails to reproduce the measurements. © 2011 Published by NRC Research Press.


Das D.,Dinhata College
Journal of the Indian Chemical Society | Year: 2011

Apparent molar volumes (V φ) and apparent molar adiabatic compressibilities (φ K) have been determined for solutions of some lithium salts (LiCl, LiBr, LiClO 4 and LiBF 4) in tetrahydrofuran at 298.15 K from density and sound velocity measurements. v φ 0 and φ K 0 of the salts have been obtained from V φ - √C and φ K - √C data. The data have been quantitatively explained in terms of ion-solvent and ion-ion interactions.

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