The distribution of neutron population in nuclear reactor is described by using transport equations. One of possible approximations of neutron transport equation is given by the neutron diffusion equation. The paper presents numerical solution method of one group neutron diffusion equation with one group of delayed neutrons.

In the present contribution, we derive from kinetic theory a unified fluid model for multicomponent plasmas by accounting for the electromagnetic field influence. We deal with a possible thermal nonequilibrium of the translational energy of the particles, neglecting their internal energy and the reactive collisions. Given the strong disparity of mass between the electrons and heavy particles, s...

The assessment of groundwater conditions within an unconfined aquifer with a periodic boundary condition is of interest in many hydrological and environmental problems. A two-dimensional numerical model for density dependent variably saturated groundwater flow, SUTRA (Voss, C.I., 1984. SUTRA: a finite element simulation model for saturated–unsaturated, fluiddensity dependent ground-water flow w...

ABSTRACT-Application of models for simulation of solute and pollutants transport in soil can reduce time and costs for remediation process. HYDRUS-1D model was developed to simulate the one–dimensional flow of soil water, heat, solute and viruses in variably saturated–unsaturated porous media. The objective of this investigation is to determine the solute transport parameters in disturbed soil ...

accurate prediction of pollution control and environmental protection need a good understanding of pollutant dynamics. numerical model techniques are important apparatus in this research area. so a 2500 line fortran 95 version code was conducted in which using approximate riemann solver, couples the shallow water and pollution transport agents in two dimensions by the aid of unstructured meshes...

Field-scale solute transport is typically difficult to model due to the complexity and heterogeneity of flow and transport in natural soils. The stream tube model attempts to stochastically describe transport across the field for relatively short travel distances by viewing the field as a series of independent vertical soil columns. This study investigates the stream tube model with the chemica...

Contaminant transport by liquid ow in a porous medium is modeled by the addition of a stochastic term to Darcy's ow equation. The resulting stochastic diierential equation is studied using results from the theory of diiusions as embodied in the Dynkin formula. The resulting integral equation for the probability distribution of uid elements is solved for the case of a spatially homogeneous mediu...

We present a quantum-kinetic equation which describes the transport phenomena in nanoelectronic devices. The equation can be regarded as a generalization of the Boltzmann equation, which describes the operation of the conventional microelectronic devices. The presented equation treats the coherent part of the transport imposed by the nanostructure potential on a rigorous quantum level, utilizin...