<title>Monte Carlo and diffusion calculations of photon migration in noninfinite highly scattering media</title>

The Monte Carlo code MCML (Monte Carlo modeling of light transport in multi-layered tissue) has been the gold standard for simulations of light transport in multi-layer tissue, but it is ineffective in the presence of three-dimensional (3D) heterogeneity. New techniques have been attempted to resolve this problem, such as MCLS, which is derived from MCML, and tMCimg, which draws upon image datasets. Nevertheless, these approaches are insufficient because of their low precision or simplistic modeling. We report on the development of a novel model for photon migration in voxelized media (MCVM) with 3D heterogeneity. Voxel crossing detection and refractive-index-unmatched boundaries were considered to improve the precision and eliminate dependence on refractive-index-matched tissue. Using a semi-infinite homogeneous medium, steady-state and time-resolved simulations of MCVM agreed well with MCML, with high precision (~100%) for the total diffuse reflectance and total fractional absorption compared to those of tMCimg (< 70%). Based on a refractive-index-matched heterogeneous skin model, the results of MCVM were found to coincide with those of MCLS. Finally, MCVM was applied to a two-layered sphere with multi-inclusions, which is an example of a 3D heterogeneous media with refractive-index-unmatched boundaries. MCVM provided a reliable model for simulation of photon migration in voxelized 3D heterogeneous media, and it was developed to be a flexible and simple software tool that delivers high-precision results.

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Vacancy-Mediated Diffusion and Diffusion-Controlled Processes in Ordered Binary Intermetallics by Kinetic Monte Carlo Simulations

Diffusion Foundations ◽

10.4028/www.scientific.net/df.29.95 ◽

2021 ◽

Vol 29 ◽

pp. 95-115

Author(s):

Rafal Kozubski ◽

Graeme E. Murch ◽

Irina V. Belova

Keyword(s):

Monte Carlo ◽

Kinetic Monte Carlo ◽

Simulation Studies ◽

Self Diffusion ◽

Monte Carlo Techniques ◽

Diffusion Controlled ◽

Kinetic Monte Carlo Simulations ◽

Kinetic Effects ◽

Kinetics Of ◽

And Diffusion

We review the results of our Monte Carlo simulation studies carried out within the past two decades in the area of atomic-migration-controlled phenomena in intermetallic compounds. The review aims at showing the high potential of Monte Carlo methods in modelling both the equilibrium states of the systems and the kinetics of the running processes. We focus on three particular problems: (i) the atomistic origin of the complexity of the ‘order-order’ relaxations in γ’-Ni3Al; (ii) surface-induced ordering phenomena in γ-FePt and (iii) ‘order—order’ kinetics and self-diffusion in the ‘triple-defect’ β-NiAl. The latter investigation demonstrated how diverse Monte Carlo techniques may be used to model the phenomena where equilibrium thermodynamics interplays and competes with kinetic effects.

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Handling of Collimated Irradiation on a Plane-Parallel Participating Medium

10.1115/imece2000-1370 ◽

2000 ◽

Author(s):

Christian Proulx ◽

Daniel R. Rousse ◽

Rodolphe Vaillon ◽

Jean-François Sacadura

Keyword(s):

Heat Flux ◽

Monte Carlo ◽

Monte Carlo Method ◽

Radiative Heat ◽

Radiative Heat Flux ◽

Scattering Media ◽

One Dimensional ◽

Plane Parallel ◽

Collimated Beam ◽

Good Agreement

Abstract This article presents selected results of a study comparing two procedures for the treatment of collimated irradiation impinging on one boundary of a participating one-dimensional plane-parallel medium. These procedures are implemented in a CVFEM used to calculate the radiative heat flux and source. Both isotropically and anisotropically scattering media are considered. The results presented show that both procedures provide results in good agreement with those obtained using a Monte Carlo method, when the collimated beam impinges normally.

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Research on the Near-Infrared (NIR) Photon Migration in the Knee

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.760-762.388 ◽

2013 ◽

Vol 760-762 ◽

pp. 388-391

Author(s):

Yan Ping Chen ◽

Xiong Ma ◽

Chun Bin Li ◽

Song Qing Chen

Keyword(s):

Monte Carlo ◽

Muscle Tissue ◽

Layered Structure ◽

Near Infrared ◽

Propagation Model ◽

Osteoarthritis Of The Knee ◽

Photon Migration ◽

Photon Propagation ◽

Non Invasive ◽

Distribution Rule

To study the phenomena of photon migration in the knee joint is very important in the field of non-invasive near-infrared optical early diagnosis of osteoarthritis of the knee (KOA). In this paper, a photon propagation model of the knee layered structure based on Monte Carlo method is proposed. The migration trace and distribution rule of the photons in knee layered structure are simulated by the Monte Carlo modeling. The proportion of photons which collide with bone tissue then migrate out of the muscle tissue and photons directly migrate out of muscle tissue is calculated and analyzed. The conclusion is that the MC method provided in this study is useful to analyze the photon migration in knee layered structure and to place the detector in a suitable position.

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