Diffusion Phenomena: Cases and Studies


Book Description

This authoritative test introduces the basic aspects of diffusion phenomena and their methods of solution through physical examples. It emphasizes modeling and methodology, bridging the gap between physico chemical statements of certain kinetic processes and their reduction to diffusion problems. Author Richard Ghez draws upon his experience in the areas of metallurgy and semiconductor technology to present physically significant examples that will prove of interest to a wide range of scientists — physicists, chemists, biologists, and applied mathematicians. Prerequisites include a rigorous year of calculus and a semester of thermodynamics. The opening chapter on the diffusion equation is succeeded by chapters on steady-state examples, diffusion under external forces, and simple time-dependent examples. An introduction to similarity is followed by explorations of surface rate limitations and segregation, a user's guide to the Laplace transform, and further time-dependent examples.




Growth and Diffusion Phenomena


Book Description

Diffusion and growth phenomena abound in the real world surrounding us. Someexamples: growth of the world's population, growth rates of humans, public interest in news events, growth and decline of central city populations, pollution of rivers, adoption of agricultural innovations, and spreading of epidemics and migration of insects. These and numerous other phenomena are illustrations of typical growth and diffusion problems confronted in many branches of the physical, biological and social sciences as well as in various areas of agriculture, business, education, engineering medicine and public health. The book presents a large number of mathematical models to provide frameworks forthe analysis and display of many of these. The models developed and utilizedcommence with relatively simple exponential, logistic and normal distribution functions. Considerable attention is given to time dependent growth coefficients and carrying capacities. The topics of discrete and distributed time delays, spatial-temporal diffusion and diffusion with reaction are examined. Throughout the book there are a great many numerical examples. In addition and most importantly, there are more than 50 in-depth "illustrations" of the application of a particular framework ormodel based on real world problems. These examples provide the reader with an appreciation of the intrinsic nature of the phenomena involved. They address mainly readers from the physical, biological, and social sciences, as the only mathematical background assumed is elementary calculus. Methods are developed as required, and the reader can thus acquire useful tools for planning, analyzing, designing,and evaluating studies of growth transfer and diffusion phenomena. The book draws on the author's own hands-on experience in problems of environmental diffusion and dispersion, as well as in technology transfer and innovation diffusion.




Numerical Methods for Diffusion Phenomena in Building Physics


Book Description

This book is the second edition of Numerical methods for diffusion phenomena in building physics: a practical introduction originally published by PUCPRESS (2016). It intends to stimulate research in simulation of diffusion problems in building physics, by providing an overview of mathematical models and numerical techniques such as the finite difference and finite-element methods traditionally used in building simulation tools. Nonconventional methods such as reduced order models, boundary integral approaches and spectral methods are presented, which might be considered in the next generation of building-energy-simulation tools. In this reviewed edition, an innovative way to simulate energy and hydrothermal performance are presented, bringing some light on innovative approaches in the field.




Modern Aspects of Diffusion-Controlled Reactions


Book Description

This monograph deals with the effects of reactant spatial correlations arising in the course of basic bimolecular reactions describing defect recombination, energy transfer and exciton annihilation in condensed matter. These effects lead to the kinetics considered abnormal from the standard chemical kinetics point of view. Numerous bimolecular reaction regimes and conditions are analysed in detail. Special attention is paid to the development and numerous applications of a novel, many-point density (MPD) formalism, which is based on Kirkwood's superposition approximation used for decoupling three-particle correlation functions.The book demonstrates that incorporation of the reaction-induced spatial correlations of similar reactants (e.g., vacancy-vacancy) leads to the development of an essentially non-Poisson spectrum of reactant density fluctuations. This can completely change the kinetics at longer times since it no longer obeys the law of mass action. The language of the correlation lengths and critical exponents similar to physics of critical phenomena is used instead. A relation between MPD theory and synergistics is discussed. The validity of the theorem giving a critical complexity for the two-step reactions exhibiting self-organization phenomena is questioned. Theoretical results are illustrated by numerous experimental data.




An Introduction to Anomalous Diffusion and Relaxation


Book Description

This book provides a contemporary treatment of the problems related to anomalous diffusion and anomalous relaxation. It collects and promotes unprecedented applications dealing with diffusion problems and surface effects, adsorption-desorption phenomena, memory effects, reaction-diffusion equations, and relaxation in constrained structures of classical and quantum processes. The topics covered by the book are of current interest and comprehensive range, including concepts in diffusion and stochastic physics, random walks, and elements of fractional calculus. They are accompanied by a detailed exposition of the mathematical techniques intended to serve the reader as a tool to handle modern boundary value problems. This self-contained text can be used as a reference source for graduates and researchers working in applied mathematics, physics of complex systems and fluids, condensed matter physics, statistical physics, chemistry, chemical and electrical engineering, biology, and many others.




Spatial Diffusion


Book Description

In this concise, clear introduction, the authors describe the theory of spatial diffusion, its method of measurement and many of its applications. The seminal work of Torsten Hagerstrand, who introduced the original spatial model of diffusion, is outlined. The authors then summarise the developments that have been made to Hagerstrand's formulation, and make suggestions for future research.




Diffusion of Technologies and Social Behavior


Book Description

Wee felt it before in sense; but now wee know it by science. Edward Misselden (1623) The collective effort reported in this volume is the outcome of the diffusion of the idea of diffusion as a fundamental process in society. The considerable number of disciplines represented here indicates the weight of the problem area. The editors are to be congratulated for their initiative in drawing together present thinking at a vivid meeting, now also in print. An old timer in the business has not much to add. But maybe some things, bearing in mind that a Preface is a celebration and not a review. As always with ideas it is hard to identify those who first gave shape to the idea of diffusion. In a general sense it is probably an observation as old as human self-reflection that groups of populations exchange ideas and copy habits and implements from each other. Sometimes it has even been recommended, as a Chinese proverb suggested millenia ago, "If you want to become a good farmer, look at your neighbor" .




Diffusion in Solids


Book Description

This book describes the central aspects of diffusion in solids, and goes on to provide easy access to important information about diffusion in metals, alloys, semiconductors, ion-conducting materials, glasses and nanomaterials. Coverage includes diffusion-controlled phenomena including ionic conduction, grain-boundary and dislocation pipe diffusion. This book will benefit graduate students in such disciplines as solid-state physics, physical metallurgy, materials science, and geophysics, as well as scientists in academic and industrial research laboratories.




Diffusion Fundamentals


Book Description




Adsorption and Diffusion


Book Description

"Molecular Sieves - Science and Technology" covers, in a comprehensive manner, the science and technology of zeolites and all related microporous and mesoporous materials. The contributions are grouped together topically in such a way that each volume deals with a specific sub-field. Volume 7 treats fundamentals and analyses of adsorption and diffusion in zeolites including single-file diffusion. Various methods of measuring adsorption and diffusion are described and discussed.