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Stochastic Perturbation (stochastic + perturbation)

Distribution by Scientific Domains
Physics and Astronomy50%

Selected Abstracts

On generalized stochastic perturbation-based finite element method

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 1 2006
Marcin Kami
Abstract Generalized nth order stochastic perturbation technique, that can be applied to solve some boundary value or boundary initial problems in computational physics and/or engineering with random parameters is proposed here. This technique is demonstrated in conjunction with the finite element method (FEM) to model 1D linear elastostatics problem with a single random variable. The symbolic computer program is employed to perform computational studies on convergence of the first two probabilistic moments for simple unidirectional tension of a bar. These numerical studies verify the influence of coefficient of variation of the random input and, at the same time, of the perturbation parameter on the first two probabilistic moments of the final solution vector. Copyright © 2005 John Wiley & Sons, Ltd. [source]

On the elastic contribution to crystal growth in complex environments

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 3 2005
A. Gadomski
Abstract Based on a number of experimental studies, we propose to consider how elastic interactions between a crystal and its surroundings change crystal growing conditions. To aim to do this, we analyze the influence of some nonequilibrium modification of the Gibbs,Thomson thermodynamic condition, prescribed at the crystal boundary, on some properties of a kinetic model of protein crystal growth in a mass-convection regime. Next, to draw the physical picture more realistically, we study the influence of a certain stochastic perturbation on the crystal growth rate. To fulfill the task we apply the description of crystal growth in terms of nonequilibrium thermodynamics at a mesoscopic level. The proposed model offers a quite comprehensive picture of the formation of modern organic crystalline materials such as non-Kossel crystals. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Decoherence of quantum tunneling by coherent phonon modes in symmetric double-well system

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 11 2004
Akira Igarashi
Abstract We investigate effect of the decoherence in quantum tunneling in one-dimensional symmetric double-well potential with coherent or stochastic perturbation. A coupling with some vibrational modes can cause the decoherence in the wavepacket dynamics. Furthermore, we discuss the controllability of the quantum tunneling by external field based on optimal control theory. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

A stochastic flow model for a tubular solution polymerization reactor

POLYMER ENGINEERING & SCIENCE, Issue 11 2007
Ardson dos S. Vianna Jr.
Residence time distributions were evaluated experimentally for three tubular solution polymerization reactors to analyze aspects of the fluid-dynamic behavior of these reactors. The analysis of the available experimental data indicates that the flow characteristics of these reactors may be subject to stochastic perturbations. A stochastic flow model is then proposed by assuming that a viscous polymer layer is formed in the proximities of the reactor walls and that plugs of polymer material are released at random during the operations. This model is able to represent the available experimental data fairly well for three tubular reactors with different configurations. POLYM. ENG. SCI., 47:1839,1846, 2007. © 2007 Society of Plastics Engineers [source]