The use of short pulse laser for minimally invasive detection scheme has become an indispensable tool in the technological arsenal of modern medicine and biomedical engineering. In this work, a time-resolved technique has been used to detect tumors/inhomogeneities in tissues by measuring transmitted and reflected scattered temporal optical signals when a short pulse laser source is incident on ...

Several preconditioners based on multigroup diffusion are developed for application to multiplying fixed-source transport problems using the discrete ordinates method. By starting from standard, one-group, diffusion synthetic acceleration (DSA), a multigroup diffusion preconditioner is constructed that shares the same fine mesh as the transport problem. As a cheaper but effective alternative, a...

The passage of a photon density wave through random media has been investigated extensively for medical imaging based on the diffusion approximation. In this paper, the photon density wave is studied based on the exact time-dependent vector radiative transfer theory. Both continuous and pulse photon density waves are analysed in a plane parallel medium using Mie scattering and the discrete ordi...

The convection-radiation effects in thermal fluid flows are studied based on the Lattice Boltzmann method. Nine-velocity flow and temperature distributions are used to obtain the mass, momentum and energy equations in thermal incompressible flows by studying equivalent moment systems. The radiative heat flux in the energy equation is obtained using the discrete-ordinates solution of the radiati...

The ADO (analytical discrete ordinates) method is used to establish a concise and accurate solution for a multi-layer radiative-transfer problem with Fresnel boundary and interface conditions. A finite plane-parallel medium composed of a number (K) of sub-strata with different material properties is considered to be illuminated by isotropically incident radiation. While a general result is obta...

An analytical version of the discrete-ordinates method is used to establish a concise and particularly accurate solution to the problem of plane Couette flow for a binary gas mixture described by the McCormack kinetic model. The solution yields, for the general sspecular-diffused case of Maxwell boundary conditions for each of the two species, the velocity, heat-flow, and shear-stress profiles ...

An analytical version of the discrete-ordinates method is used to solve the classical problems of Poiseuille +ow and thermal-creep +ow in a plane channel. The kinetic theory for the rare4ed-gas +ow is based on the S model (a generalization of the BGK model), and in addition to the use of the di9use–specular re+ection model (based on a single accommodation coe:cient) for describing particle scat...

The cessation of nuclear testing in the United States during the 1990’s created an increased need for improvements in other tools used to maintain the stockpile. The Accelerated Strategic Computing Initiative (ASCI) was created to address a broad range of computational challenges at the U.S. weapons laboratories, encompassing both hardware and software. Algorithmic improvements were sought in a...

The liquid rocket propellant burns inadequately in the combustion chamber; therefore, exhaust gas reacts with oxygen and heat that was generated, which turn affects thermal environment. By using finite-rate chemical kinetics discrete ordinates method, calculation model for four-engine flowfield is established, numerically investigates afterburning effect on environment of engine plume under dif...

ABSTRACT We introduce the radiative transfer code Sweep for cosmological simulation suite arepo. is a discrete ordinates method in which equation solved under infinite speed of light, steady state assumption by transport sweep across entire computational grid. Since arepo based on an adaptive, unstructured grid, dependency graph induced dependencies grid cells non-trivial. In order to solve top...