نتایج جستجو برای: diffusion reaction equation
تعداد نتایج: 771388 فیلتر نتایج به سال:
The classical wave-of-advance model of the neolithic transition (i.e., the shift from hunter-gatherer to agricultural economies) is based on Fisher’s reaction-diffusion equation. Here we present an extension of Einstein’s approach to Fickian diffusion, incorporating reaction terms. On this basis we show that second-order terms in the reaction-diffusion equation, which have been neglected up to ...
the release of fe from soil solid phases into soil solution is a dynamic process that regulates the continuous supply of this element to growing plants. to ascertain the pattern of fe release, the kinetics of fe release from six soils by diethylenetriaminepentaacetic acid (dtpa) solution were investigated using soil samples taken from two different agroclimatic regions of iran. all soils were c...
Birth-jump models are designed to describe population models for which growth and spatial spread cannot be decoupled. A birth-jump model is a nonlinear integro-differential equation. We present two different derivations of this equation, one based on a random walk approach and the other based on a two-compartmental reaction-diffusion model. In the case that the redistribution kernels are highly...
The problem of wave-front propagation for the n-dimensional reaction-diffusion system involving Kolmogorov-Petrovskii-Piskunov kinetics and the diffusion transport with a finite velocity has been considered. By using a scaling procedure we have given an asymptotic derivation of the equation governing the evolution of a reaction front in the long-time large-distance limit. It has been found that...
The fast reaction limit of a volume-surface reaction-diffusion system is rigorously investigated. We show that as the reaction rate constant goes to infinity, the original system converges to a heat equation with dynamical boundary condition. As a consequence, a dynamical boundary condition can be interpreted as a fast reaction limit of a volume-surface reaction-diffusion system.
We perform a thorough study of the blow up profiles associated to following second order reaction-diffusion equation with non-homogeneous reaction:?tu=?xx(um)+|x|?up, in range exponents 10. classify solutions self-similar form, that are likely represent typical patterns for general solutions. thus show coefficient |x|? has strong influence on qualitative aspects related finite time u...
The propagating chemical fronts found in cubic autocatalytic reactiondiffusion processes are studied. Simulations of the reaction-diffusion equation near to and far from the onset of the front instability are performed and the structure and dynamics of chemical fronts are studied. Qualitatively different front dynamics are observed in these two regimes. Close to onset the front dynamics can be ...
A number of nonlinear phenomena in many branches of sciences such as physical [6], chemical, economical [20] and biological processes [15,14] are described by the interplay of reaction and diffusion or by the interaction between convection and diffusion. One of the well-known partial differential equations (PDEs) which governs a wide variety of them is Burgers equation, which provides the simpl...
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