803,353 research outputs found

    Correlation between bulk and surface properties in Cd–X (X=Hg, Mg) liquid alloys

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    A theoretical investigation of the energetics and its effect on the alloying behaviour of Cd–Hg and Cd–Mg liquid alloys have been carried out with the aim of correlating their bulk and surface phenomena. Using the Quasi-chemical approximation for regular solution model, our results indicate that Cd–Hg and Cd–Mg are weakly heterocoordinated both in the bulk and on the surface. We observed that the degree of chemical order in Cd–Mg liquid alloy is more than that of Cd–Hg liquid alloy

    Momentum Space Integral Equations for Three Charged Particles: Diagonal Kernels

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    It has been a long-standing question whether momentum space integral equations of the Faddeev type are applicable to reactions of three charged particles, in particular above the three-body threshold. For, the presence of long-range Coulomb forces has been thought to give rise to such severe singularities in their kernels that the latter may lack the compactness property known to exist in the case of purely short-range interactions. Employing the rigorously equivalent formulation in terms of an effective-two-body theory we have proved in a preceding paper [Phys. Rev. C {\bf 61}, 064006 (2000)] that, for all energies, the nondiagonal kernels occurring in the integral equations which determine the transition amplitudes for all binary collision processes, possess on and off the energy shell only integrable singularities, provided all three particles have charges of the same sign, i.e., all Coulomb interactions are repulsive. In the present paper we prove that, for particles with charges of equal sign, the diagonal kernels, in contrast, possess one, but only one, nonintegrable singularity. The latter can, however, be isolated explicitly and dealt with in a well-defined manner. Taken together these results imply that modified integral equations can be formulated, with kernels that become compact after a few iterations. This concludes the proof that standard solution methods can be used for the calculation of all binary (i.e., (in-)elastic and rearrangement) amplitudes by means of momentum space integral equations of the effective-two-body type.Comment: 36 pages, 2 figures, accepted for publication in Phys. Rev.

    Proton-Deuteron Elastic Scattering from 2.5 to 22.5 MeV

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    We present the results of a calculation of differential cross sections and polarization observables for proton-deuteron elastic scattering, for proton laboratory energies from 2.5 to 22.5 MeV. The Paris potential parametrisation of the nuclear force is used. As solution method for the charged-composite particle equations the 'screening and renormalisation approach' is adopted which allows to correctly take into account the Coulomb repulsion between the two protons. Comparison is made with the precise experimental data of Sagara et al. [Phys. Rev. C 50, 576 (1994)] and of Sperison et al. [Nucl. Phys. A422, 81 (1984)].Comment: 24 pages, 8 eps figures, uses REVTe

    Magnetic polarizabilities of light mesons in SU(3)SU(3) lattice gauge theory

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    We investigate the masses (ground state energies) of neutral pseudoscalar and vector meson in SU(3)SU(3) lattice gauge theory in strong abelian magnetic field. The energy of ρ0\rho^0 meson with zero spin projection sz=0s_z=0 on the axis of the external magnetic field decreases, while the energies with non-zero spins sz=1s_z=-1 and +1+1 increase with the field. The energy of π0\pi^0 meson decrease as a function of the magnetic field. We calculated the magnetic polarizabilities of pseudoscalar and vector mesons for lattice volume 18418^4. For ρ0\rho^0 with spin sz=1|s_z|=1 and π0\pi^0 meson the extrapolations to zero lattice spacing have been done. We do not observe any evidence in favour of tachyonic mode existence.Comment: 9 pages, 13 figure

    Evaluation of the effectiveness of business-processes in international e-commerce system

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    A comparative study of Zinc (II) ions removal by a locally produced Granular activated carbon

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    Physiochemical properties of wastewater effluent from the plants of a brewery in Lagos, Nigeria were analyzed. The adsorption capacity of Granular activated carbon from animal horns when compared with the available commercial Granulated Activated Carbon (GAC) has been presented. Kinetics of adsorption was also investigated. The adsorption isotherms could be well defined with Freundlich model instead of Langmuir model for both GAC studied. The experimental data, when applied to the first and second-order kinetic models, followed the first-order with r² = 0.931 for GAC from animal horns while commercial GAC followed the second-order with r² = 0.936. The results illustrated how animal horns, a solid waste disposal menace from the abattoir at the Oshodi market in Lagos metropolis, was used as an effective biosorbent for the removal of Zn 2+ ions; offering a cheap option for primary treatment of the wastewater effluent
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