摘要:

A new approach to the problem of reduced description for Boltzmann-type systems is developed. It involves a direct solution of two main problems: thermodynamicity and dynamic invariance of reduced description. A universal construction is introduced, which gives a thermodynamic parameterization of an almost arbitrary approximation. Newton-type procedures of successive approximations are developed which correct dynamic noninvariance. The method is applied to obtain corrections to the local Maxwell manifold using parametrics expansions instead of Taylor series into powers of Knudsen number. In particular, the high frequency acoustic spectra is obtained.

ISSN:0041-1450    

DOI:10.1080/00411459408204345

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

This paper is concerned with the large-time asymptotic behaviour of the solution to transport Cauchy problems in slab geometry withgeneral boundary operatorsHrelating the incoming and outgoing fluxes. It is composed of two parts. First, we consider the transport Cauchy problems with a general class of dissipative or conservative boundary conditions (∥H∥ ≤ 1). In the second part, we treat the case of an arbitrary compact boundary operatorHwith no restriction on its norm. Our approach relies on the inverse Laplace transform and applies to dissipative as well as multiplying boundary conditions.

ISSN:0041-1450    

DOI:10.1080/00411459408204346

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The problem of optimal planting and cutting of industrial wood is considered. The criterion for optimization is to maximize the capture of solar energy by a plant stand. The optimization algorithm is based on variation of solar radiation in tree crowns caused by variations in tree density (planting and cutting of trees) and size (tree growth). An equation for optimal value of tree density is derived. Numerical results are presented to illustrate the influence of canopy parameters on the input coefficients of the derived equation.

ISSN:0041-1450    

DOI:10.1080/00411459408204347

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A method is developed for P1synthetic acceleration of outer iterations. The method is consistent with the weighted diamond differencing discrete ordinates multigroup equation, and suitable for a negative flux fixup algorithm being used in transport calculations. The scattering anisotropy is considered in the most general form by means of the scattering matrix. Being applied to the slab geometry, heterogeneous, anisotropic scattering neutron thermalization problems, the method gives a gain by a factor of 3 to 5 in running time relative to an ordinary source iteration calculation. It is also shown, that a convergence rate of the method depends slightly on the spatial mesh.

ISSN:0041-1450    

DOI:10.1080/00411459408204348

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

In proving existence of solutions to the Wigner-Poisson (WP) system1,2,3and, indeed, to many systems of partial differential equations, conservation laws are often used to prove that a local solution does not blow up in a finite time interval, and hence is a global-in-time solution. For the (WP) system, one proves1,2a relevant conservation principle referred to as “energy conservation” which takes the form1,2,3

ISSN:0041-1450    

DOI:10.1080/00411459408204349

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor