Showing papers by "Government College published in 1994"

Anisotropic spheres with variable energy density in general relativity

Abstract: Interior solutions of Einstein field equations for anisotropic spheres with variable energy density are obtained. The solutions for uniform energy density [10] and for radial pressure equal to zero [11] are particular cases of the present solution. With this solution we are also able to discuss an anisotropic gas sphere. Physically it explains larger red-shifts of different quasi-stellar objects. The results of the model have been used to explain the behaviour of a neutron stars and conclude that the maximum mass of a neutron star does not exceed two solar masses, which confirms the Chandrasekhar limit.

Viscosity of nonelectrolyte liquid mixtures. III Binary mixtures of methyl methacrylate with hydrocarbons, haloalkanes, and alkylamines

Abstract: Measurements of the viscosityη and the densityϱ are reported for 14 binary mixtures of methyl methacrylate (MMA) with hydrocarbons, haloalkanes, and alkylamines at 303.15 K. The viscosity data have been correlated with equations of Grunberg and Nissan, of McAllister, and of Auslaender. Furthermore, excess viscosityΔ Inη and excess Gibbs energy of activationΔG* E of viscous flow have been calculated and have been used to predict molecular interactions occurring in present binary mixtures. The results show the existence of specific interactions in MMA + aromatic hydrocarbons, MMA + haloalkanes, and MMA + primary amines.

Limiting wave growth for electron cyclotron waves

Abstract: Quasilinear weak diffusion theory presented by Kennel and Petschek (1966) and advanced by Schulz and Davidson (1988) is further extended to put an upper limit on the growth of electron cyclotron waves. It is shown that the power gain of whistler mode electron cyclotron wave (other than plasmaspheric hiss) can not exceed 40 dB. Inside the outer radiation belt, the upper limit of temporal wave growth is ≈350 rad s−1 and normalised wave growth is 0.017. The limits are independent of the kind of the electron diffusion and are applicable for on the equator/off the equator locations of wave-particle interactions.

Regimes of contradiction in the study of strong diffusion

Abstract: Various aspects of Etchetoet al.'s theory are studied in detail. It is shown that the inequalitya

A quantitative analysis of binding affinities of ligands active at adenosine receptors.

Abstract: Binding affinities, pKi's, of 1,3-dipropyl-8-phenylxanthines and 8-substituted xanthines as selective antagonists at A(1)- and A(2)- adenosine receptors, were quantitatively analysed in terms of hydrophobic parameter, pi, and van der Waals volume, Vw. For ligands of the first series, the hydrophobicity of para-substituents and the bulk of meta-substituents are shown to be the deciding factors. Similarly, for the other series, the binary substitutions at X-, Y- and R-positions, highlighted by respective dummy variables, and the bulk rendered by groups at R(1)-position, are found to be significantly correlated with A(1)- and A(2)-receptor affinities. Additionally, the Free-Wilson study of this series resulting into individual substituent contribution, provides similar inferences to these, but in a more exact manner. This study also hints at the possibility of a different accommodation site at the receptor for the R(1)-substituents of the congeners on account of conformational dissimilarity of A(1)- and A(2)-receptors.

Tourism and Corals in the Bay of Bengal Islands

Abstract: T coral reefs of the Bay islands which lie in IndoPacific waters and stretch over 1,962 km in the Bay of Bengal, harbour about 200 species of corals and comprise a great tourist attraction. North Andaman, North Reef, Ritchie's Archipelago, the Labyrinth group of islands in South Andaman, Little Andaman, Non Cowry, Kamorta, Tillanchang, Little Nicobar, and Great Nicobar, are islands or groups that should be mentioned. The dominant reefbuilding massive corals are species of Favia, Favites, Platygyra, Symphallia, Coniastrea, Diplostrea, and Porites; the branching corals include species of Pacillapora, Stylopora, Seriotopora, Acropora, and Montipora, while the soft corals are species of Helipora, Millepora, Tubipora, Alcynaria, and Gorgonia. The reefs are of the fringing type, with series of patchreefs along shores, especially in bays and inlets. A 320-kmlong barrier reef exists along the west coast of the Andamans, with a 4-m-deep lagoon. Channel reefs are found in Ritchie's Archipelago and South Andaman. Knoll (round hillode of hump-line structure) occurs in channels adjoining the fringing reef of the adjacent islands. In the Andamans the reef-flat extends up to 500 m from the shore, while in the Nicobars it may do so to 1,000 m.