Pandey V.,Bsa College |
Gupta S.,Agra College |
Tomar D.S.,Rbs College |
Goyal S.C.,P.A. College
Physica B: Condensed Matter | Year: 2010
The Anderson-Grneisen parameter (δ) is of considerable importance to Earth scientists because it sets limitations on the thermo-elastic properties of the lower mantle and core. However, there are several formulations on the Grneisen parameter, which are in frequent use and predict varying dependence of δ as a function of temperature. In this paper, the expressions for thermal expansion, thermal expansion coefficients and bulk modulus are obtained considering the anharmonic dependence on temperature and are applied to study these constants to alkaline earth oxides. Using the derived expressions, we have shown that different parameters on which the AndersonGrneisen parameter (δ) depends are temperature dependent, but above all the AndersonGrneisen parameter (δ) is independent of temperature. The results obtained have been found to be comparable to experimentaldata. © 2010 Elsevier B.V. All rights reserved.
Agarwal M.,Bsa College |
Chauhan S.,Academy of Life science
Medicinal Plants | Year: 2015
In the present study antibacterial activity of aqueous and alcoholic extracts of stem bark and leaves of Dolichandwne falcata (Wall, ex DC.) Seem (Bignoniaceae) was tested against MDR isolates DKU-156 and JAL-1236 of M. tuberculosis, reference susceptible strain M. tuberculosis H37Rv as well as fast growing mycobacterial pathogen M. fortuitum (TMC-1529). The leaves and bark collected between spring and summer season were dried and extracts was prepared using three portions of the dried powdered bark and leaves. It was soaked separately in 500 ml of distilled water and ethanol (98%) for 72 h and refluxed and filtrates were concentrated under vacuum at 40° C to obtain the dry extracts. Reference drug susceptible strain M. tuberculosis H37Rv as control, multi-drug resistant isolates DKU-156, JAL-1236 and fast growing mycobacterial pathogen M. fortuitum (TMC-1529) were used during the present investigation. Antimicrobial assays were performed in Lowenstein Jensen (L-J) medium and Middlebrook 7H9 broth in BacT/ALERT 3D system (Sigma-Aldrich, St. Louis, USA). The aqueous and alcoholic extracts of stem bark and leaves were incorporated in the media. Susceptibility testing of MDR isolates was also performed against streptomycin in the same batch of media for comparison of cfu on drug free controls. The results of the present investigation clearly showed that the aqueous extracts of stem bark were more effective as compared to aqueous and leaf extracts and alcoholic stem bark and leaf extracts. © 2015, IndianJournals.com. All rights reserved.
Kumar A.,Institute of Engineering and Technology |
Kaanodiya K.K.,BSA |
Pachauri R.R.,Bsa College
International Journal of Industrial Engineering Computations | Year: 2011
This study presents optimal ordering policies for retailer when supplier offers cash discount and two progressive payment schemes for paying of purchasing cost. If the retailer pays the outstanding amount before or at first trade credit period M, the supplier provides ^cash discount and does not charge any interest. If the retailer pays after M but before or at the second trade period N offered by the supplier, the supplier provides r2 cash discount and charges 31 May 2011 interest on unpaid balance at the rate lc1. If retailer pays the balance after N, (N > M) then the supplier does not provide any cash discount but charges interest on unpaid balance at the rate lc2. The primary objective of this paper is to minimize the total cost of inventory system. This paper develops an algebraic approach to determine the optimal cycle time, optimal order quantity and optimal relevant cost. Numerical example are also presented to illustrate the result of propose model and solution procedure developed. © 2011 Growing Science Ltd. All rights reserved.
Pandey V.,Bsa College |
Pandey V.,Agra College |
Gupta S.,Bsa College |
Gupta S.,Agra College |
And 4 more authors.
Phase Transitions | Year: 2010
In this article, we have investigated the high-pressure structural phase transition of alkaline earth oxides using the three-body potential (TBP) model. Phase transition pressures are associated with elastic constants. An effective inter-ionic interaction potential (TBP) with long-range Coulomb interactions and the Hafemeister-Flygare type short-range overlap repulsion and the vdWl interaction is developed. The present calculations have revealed reasonably good agreement with the available experimental data on structural transition (B1-B2 structure). The phase transition pressures Pt of MgO, CaO, SrO, and BaO occur at 220, 45, 40, and 100 GPa, respectively. Further, the variations of the second-order elastic constants with pressure have followed a systematic trend, which are almost identical to those exhibited by the observed data measured for other semiconducting compounds with rocksalt (B1)-type crystal structure. It is found that TBP promises that we would be able to predict phase transition pressure and elastic constants for other chalcogenides as well. The results may be useful for geophysical study. © 2010 Taylor & Francis.
Sarkar B.K.,Vellore Institute of Technology |
Verma A.S.,Panjab University |
Gupta R.C.,Bsa College |
Singh K.,Bsa College
International Journal of Thermophysics | Year: 2010
Using photoacoustic spectroscopy, the composition-dependent absorption coefficient (a), thermal diffusivity (φ), and optical bandgap (E g) of Zn 1-xMn xTe diluted magnetic semiconductor have been measured. For higher Mn compositions, the absorption spectrum of the Zn-Mn-Te system consists of three regions, viz., the high absorption region, the exponential region, and the weak absorption tail. The band- gap follows a nonlinear variation with composition, showing a downward bowing with a minimum around x = 0.31 as a consequence of the electro-negativity difference between the substituted atoms. The composition-dependent band-edge effective mass of the carriers does not show the bowing behavior indicating that the momentum matrix is not the same for all the Zn 1-xMn xTe alloys due to different lattice constants. The absorption spectra show that the transition is allowed and direct. © US Government 2010.