scholarly journals Numerical Study of Light Transport in Apple Models Based on Monte Carlo Simulations

Photonics ◽  
2015 ◽  
Vol 3 (1) ◽  
pp. 2 ◽  
Author(s):  
Mohamed Askoura ◽  
Fabrice Vaudelle ◽  
Jean-Pierre L’Huillier
1998 ◽  
Vol 376 ◽  
pp. 149-182 ◽  
Author(s):  
MICHAEL B. MACKAPLOW ◽  
ERIC S. G. SHAQFEH

The sedimentation of fibre suspensions at low Reynolds number is studied using two different, but complementary, numerical simulation methods: (1) Monte Carlo simulations, which consider interparticle hydrodynamic interactions at all orders within the slender-body theory approximation (Mackaplow & Shaqfeh 1996), and (ii) dynamic simulations, which consider point–particle interactions and are accurate for suspension concentrations of nl3=1, where n and l are the number density and characteristic half-length of the fibres, respectively. For homogeneous, isotropic suspensions, the Monte Carlo simulations show that the hindrance of the mean sedimentation speed is linear in particle concentration up to at least nl3=7. The speed is well predicted by a new dilute theory that includes the effect of two-body interactions. Our dynamic simulations of dilute suspensions, however, show that interfibre hydrodynamic interactions cause the spatial and orientational distributions to become inhomogeneous and anisotropic. Most of the fibres migrate into narrow streamers aligned in the direction of gravity. This drives a downward convective flow within the streamers which serves to increase the mean fibre sedimentation speed. A steady-state orientation distribution develops which strongly favours fibre alignment with gravity. Although the distribution reaches a steady state, individual fibres continue to rotate in a manner that can be qualitatively described as a flipping between the two orientations aligned with gravity. The simulation results are in good agreement with published experimental data.


1993 ◽  
Vol 32 (4) ◽  
pp. 426 ◽  
Author(s):  
R. Graaff ◽  
M. H. Koelink ◽  
F. F. M. de Mul ◽  
W. G. Zijlstra ◽  
A. C. M. Dassel ◽  
...  

1997 ◽  
Vol 35 (3) ◽  
pp. 287-288 ◽  
Author(s):  
V. G. Kolinko ◽  
F. F. M. de Mul ◽  
J. Greve ◽  
A. V. Priezzhev

1994 ◽  
Vol 358 ◽  
Author(s):  
L. Pavesi ◽  
H. Eduardo Roman

ABSTRACTWe present a detailed study of the time-resolved photo-luminescence of porous Silicon samples with different porosities providing clear evidence of anomalous relaxation behaviour of the luminescence, which follows stretched exponential decay for a variety of experimental conditions. In addition, a numerical study of the underlying transport behaviour in these disordered materials by means of Monte-Carlo simulations has been performed. Nanometer sized particles, characterised by a distribution of radiative and non-radiative recombination times, are randomly placed at the sites of a cubic lattice forming a single three dimensional percolation cluster. Charge carriers are allowed to hop between nearest-neighbour occupied sites. The competing effect between radiative and non-radiative transitions in a single nanometer particle, as well as the effects of geometrical constraints on transport due to the complex topology, are discussed and compared to experiments.


Author(s):  
Matthew T. Johnson ◽  
Ian M. Anderson ◽  
Jim Bentley ◽  
C. Barry Carter

Energy-dispersive X-ray spectrometry (EDS) performed at low (≤ 5 kV) accelerating voltages in the SEM has the potential for providing quantitative microanalytical information with a spatial resolution of ∼100 nm. In the present work, EDS analyses were performed on magnesium ferrite spinel [(MgxFe1−x)Fe2O4] dendrites embedded in a MgO matrix, as shown in Fig. 1. spatial resolution of X-ray microanalysis at conventional accelerating voltages is insufficient for the quantitative analysis of these dendrites, which have widths of the order of a few hundred nanometers, without deconvolution of contributions from the MgO matrix. However, Monte Carlo simulations indicate that the interaction volume for MgFe2O4 is ∼150 nm at 3 kV accelerating voltage and therefore sufficient to analyze the dendrites without matrix contributions.Single-crystal {001}-oriented MgO was reacted with hematite (Fe2O3) powder for 6 h at 1450°C in air and furnace cooled. The specimen was then cleaved to expose a clean cross-section suitable for microanalysis.


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