BITS Faculty Publications

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Start date: 1984End date: 1989

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    Density functional calculation of Compton profiles of metals using phase-space approach
    (Elsevier, 1987-12) Mishra, Rashmi Ranjan
    Spherically averaged electron momentum densities (EMD) in Al, V and Cu metals have been calculated by using density functional theory in the phase-space approach. Compton profiles, J(q) and expectation values 〈pn〉 have been computed. These theoretical results show satisfactory agreement with the experimental data for Al, V and Cu.
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    Transformation from metallic electron charge density to electron momentum
    (Elsevier, 1986-12) Mishra, Rashmi Ranjan
    Electron momentum densities (EMD) in Al, V, Cr and Cu metals have been estimated from the metallic electron charge densities by applying the procedure of Burkhardt, Konya and Coulson and March. The procedure has provided spherically averaged EMD from which corresponding Compton profiles, J(q) and 〈pn〉 expectation values have been computed. These theoretical results show satisfactory agreement with the experimental data for Al, V, Cr and Cu.
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    Modal Characteristics of a doubly clad step- index optical fiber- general analytical approach
    (Canadian Science Publishing, 1988) Chaubey, V.K.
    Using a fairly rigorous approach, a general characteristic equation for a doubly clad step-index fibre has been derived under the assumption that the refractive-index difference between the inner and outer cladding is small. Two different profiles, i.e., the W profile and the staircase profile, have been treated together and a discussion of their common characteristics has been made. Cutoff conditions for low-order modes have been obtained. For a certain range of values of the transverse-phase parameter ratio, the singly-clad fibre has greater mode cutoff V numbers than those of a doubly clad fibre. The analysis anticipates the possibility of obtaining greater cutoff V numbers for W-profile fibres.
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    Information arrivals, stock price variability and market efficiency in Indian stock market
    (ISAE, 1984) Giri, Arun Kumar
    NB-Figures in brackets indicate percentages across the categories. cultivators owning land within the deep tubewell command area belonged only to the marginal and small size-group of farmers. The presence of the medium and large size-group of farmers was not observed. The medium and large category of farmers although existed a few years back, have now been reduced to marginal and small farmers. Out of 150 owner farmers, 77 per cent belonged to the marginal category cultivating 53.29 acres, constituting 59 per cent of the total area of 90.83 acres under the deep tubewell. The small farmers constituted only 23 per cent and cultivated 41 per cent of the land. The average size of owned land of the marginal and the small farmers within the deep tubewell command area was 046 acre and 1.10 acre respectively.
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    Magnetic resonance lineshapes in powdered and amorphous systems
    (IAS, 1986-04) Sivasubramanian, S.C.
    A survey is made of the theory and applications ofEPR andNMR absorption lineshapes observed in powdered and amorphous materials. The ‘spin Hamiltonian’ and ‘resonance condition’ formalisms are reviewed, andepr andnmr lineshapes are discussed which typify the singularity characteristics in powdered materials. In the amorphous or ‘glassy’ state, the measurable spin resonance parameters often have to be viewed as being ‘randomly distributed’ according to a probability density function. Several recent probability-theory based approaches to lineshape computation for modelling the amorphous state are discussed.
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    Heavy metal Uptake in the Cynobacterium Nostoc calcicola.
    (IBS, 1988) Verma, Sanjay Kumar
    The literature on the inhibitory effect of copper on growth (Les &Walker, 1984), photosynthesis (Shiol et al, 1978) and nitrogen fixation (Rai & Raizada, 1985) in algae and higher plants is impressive. Heavy metals inhibit the uptake and assimilation of nutrients (Singh & Yadava, 1983, 1984). Mechanisms governing the metal uptake process in microorganisms (Bhattacharjee, 1986) and in cyanobacteria (Singh & Yadava, 1985) are investigated. The possibility of involvement of carrier (s) and energy in the metal transport across the cell membranes has been suggested (Veltrup, 1977). The toxicity of heavy metal to algae (Hargreaves & Whitton, 1976 a,b; Singh & were diluted to S hli with triple glass distilled water. A furher Pandey 1981) is influenced by environmental factors like pH, light and complexans. However, there have been only a few studies on the effect of environmental factors on copper uptake in cyanobacteria. The present investigation reports on the copper uptake kinetics and the role of various factors on Nostoc calcicola.
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    Copper uptake by free and immobilized cyanobacterium
    (OUP, 1989) Verma, Sanjay Kumar
    Copper uptake in free and immobilized cells of the cyanobacterium Nostoc calcicola has been examined. The immobilized cells invariably maintained a higher profile of Cu intake rate (12.7 nmol mg−1 protein min−1) over the free cells (6.0 nmol mg−1 protein min−1). The total Cu uptake in immobilized cells was almost two and a half-times more than their free cell counterpart under identical experimental conditions. Also, the immobilized cells showed a stronger positive correlation between Cu adsorption and uptake. The results have been discussed in terms of improved metabolic efficiency of immobilized cells.