Radiative Properties of Dense Fibrous Medium Containing Fibers in the Geometric Limit

2006 ◽  
Vol 128 (10) ◽  
pp. 1022-1030 ◽  
Author(s):  
R. Coquard ◽  
D. Baillis
Keyword(s):  
Monte Carlo ◽  
Extinction Coefficient ◽  
Phase Function ◽  
Fibrous Material ◽  
Radiative Properties ◽  
Circular Cylinders ◽  
Fibrous Materials ◽  
Geometric Optics ◽  
Shadowing Effect ◽  
Radiative Characteristics

The aim of this paper is to investigate the dependent regime in dense fibrous materials with size parameters ranging in the geometric optics limit. We use a method based on a Monte Carlo procedure which permits one to identify the radiative properties of dispersed media. This method is applied to materials made of opaque or semitransparent randomly oriented long circular cylinders representing the fibers. The results permit us to investigate the limit of validity of independent scattering hypothesis and to analyze the evolution of the extinction coefficient, scattering albedo and phase function of the fibrous material with the porosity and the reflecting properties of the particles when the shadowing effect due to geometric sized objects is not negligible. We also propose a correlation to estimate the radiative properties in dependent regime from the results of the independent scattering hypothesis. Thereafter, the radiative characteristics obtained are compared to those predicted by previous authors.

Comment on ‘The use of the Henyey–Greenstein phase function in Monte Carlo simulations in biomedical optics’

2006 ◽  
Vol 51 (22) ◽  
pp. L39-L41 ◽  
Author(s):  
T Binzoni ◽  
T S Leung ◽  
A H Gandjbakhche ◽  
D Rüfenacht ◽  
D T Delpy
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Phase Function ◽  
Biomedical Optics

Reduction of Computing Time and Improvement of Convergence Stability of the Monte Carlo Method Applied to Radiative Heat Transfer With Variable Properties

1989 ◽  
Vol 111 (1) ◽  
pp. 135-140 ◽  
Author(s):  
M. Kobiyama
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Computing Time ◽  
Energy Difference ◽  
Radiative Properties ◽  
Radiative Energy ◽  
Control Element ◽  
The Monte Carlo Method ◽  
The Difference ◽  
Convergence Stability

A modified Monte Carlo method is suggested to reduce the computing time and improve the convergence stability of iterative calculations without losing other excellent features of the conventional Monte Carlo method. In this method, two kinds of radiative bundle are used: energy correcting bundles and property correcting bundles. The energy correcting bundles are used for correcting the radiative energy difference between two successive iterative cycles, and the property correcting bundles are used for correcting the radiative properties. The number of radiative energy bundles emitted from each control element is proportional to the difference in emissive energy between two successive iterative cycles.

scholarly journals The 3D structure of fibrous material is fully restorable from its X-ray diffraction pattern

IUCrJ ◽  
2021 ◽  
Vol 8 (4) ◽  
Author(s):  
Hiroyuki Iwamoto
Keyword(s):  
Diffraction Pattern ◽  
Fibrous Material ◽  
3D Structure ◽  
Wide Field ◽  
Fibrous Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Fiber Diffraction ◽  
Puzzle Solving ◽  
Diffraction Patterns

X-ray fiber diffraction is potentially a powerful technique to study the structure of fibrous materials, such as DNA and synthetic polymers. However, only rotationally averaged diffraction patterns can be recorded and it is difficult to correctly interpret them without the knowledge of esoteric diffraction theories. Here we demonstrate that, in principle, the non-rotationally averaged 3D structure of a fibrous material can be restored from its fiber diffraction pattern. The method is a simple puzzle-solving process and in ideal cases it does not require any prior knowledge about the structure, such as helical symmetry. We believe that the proposed method has a potential to transform the fiber diffraction to a 3D imaging technique, and will be useful for a wide field of life and materials sciences.

scholarly journals Symbolic Monte Carlo method applied to the identification of radiative properties of a heterogeneous material

2020 ◽  
Vol 249 ◽  
pp. 107019
Author(s):  
Yassine Maanane ◽  
Maxime Roger ◽  
Agnès Delmas ◽  
Mathieu Galtier ◽  
Frédéric André
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Heterogeneous Material ◽  
Radiative Properties

Investigating the Effects of Fibrous Material Compression on the Acoustical Behavior of Absorption and Barrier Materials

2006 ◽  
Vol 129 (2) ◽  
pp. 133-140 ◽  
Author(s):  
A. R. Ohadi ◽  
M. Moghaddami
Keyword(s):  
Absorption Coefficient ◽  
Fibrous Material ◽  
Transmission Loss ◽  
Element Model ◽  
Physical Parameters ◽  
Fibrous Materials ◽  
Barrier Materials ◽  
Rigid Frame ◽  
Absorbing Materials ◽  
The Galerkin Method

This paper discusses the effects of compression on acoustical performance of fibrous materials. A finite element model is used to predict the absorption coefficient and transmission loss of absorbing and barrier materials. This model is developed based on the Galerkin method and includes the equation of wave propagation in rigid frame porous material. The compression of fibrous material is entered to the model with relations that explain modifications of physical properties used in the wave equation. Acoustical behavior of absorption and barrier materials with and without compression is studied. It is shown that compression of the material leads to reduction of the transmission loss of the barrier materials and absorption coefficient of absorbing materials. In this regard, “thickness reduction” and “variations of physical parameters” due to compression are investigated.

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