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A continuous slowing down theory for test particles interacting wit ha statistical system in the presence of an external field
No full textNumerical solutions to the Boltzmann equation for rarefied gases via a local Green's function technique
No full textThe distribution function continuity method: a local Green's function technique for the numerical solution of the Boltzmann equation
No full textOn a quasilinear parabolic system modelling the diffusion of radioactive isotopes
Get PDFWe consider a model for the diffusion of N species
of isotopes of the same element in a medium, consisting in a
parabolic quasilinear system, with Dirichlet boundary condition,
in the general hypothesis that the diffusion coefficients possibly
are all different. We prove existence and uniqueness of classical solution in the physically relevant assumption that the total
concentration of the element is positive and bounded
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
On a model for the propagation of isotopic disequilibrium by diffusion
No full textWe consider a model for the distribution of radionuclides in the ground water around a deep repository for used nuclear fuel, based on the assumption that different isotopes of the same chemical element A contribute jointly to the chemical potential of A. In this hypothesis, the total flux of a particular isotope has two components, one due to the interaction with the solvent molecules B, the other with the kin isotopes. We study some qualitative properties of the solution in the physically relevant assumption that the first of these components is negligible. In this assumption the problem reduces to a parabolic equation for the total concentration of the element A, coupled with hyperbolic equations for the concentrations of the single isotopes
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