%0 Book Section %1 statphys23_0984 %A Taitelbaum, H. %B Abstract Book of the XXIII IUPAP International Conference on Statistical Physics %C Genova, Italy %D 2007 %E Pietronero, Luciano %E Loreto, Vittorio %E Zapperi, Stefano %K front mean-field membrane percolation reaction-diffusion statphys23 topic-4 %T Reaction-Diffusion Front Anomalies due to Spatial Restrictions %U http://st23.statphys23.org/webservices/abstract/preview_pop.php?ID_PAPER=984 %X We study the front characteristics in the A+B $\rightarrow$ C reaction-diffusion system with initially-separated reactants, in two realistic cases of spatial restrictions: a) Disordered media, exemplified by two-dimensional (2D) percolation 1. We investigate the front characteristics as a function of the disorder degree in the system, in particular close to criticality. We show that the front width exponent is larger than the mean-field (MF) exponent of 1/6, and at criticality it approaches 1/4 , which is the one-dimensional (1D) exponent. The results are discussed in the context of other systems with attenuated transport, where the front width exponent is smaller than the MF exponent. We also study the short-time behavior of the front width exponent, and discuss the validity of the scaling relations between the relevant exponents. b) Initial separation between the reactants by a finite-sized, semi-permeable wall, which allows only one reactant to diffuse through 2. Theoretically, the ratio of the diffusive fluxes of the two species has been defined before as a control parameter and was predicted to give rise to a localization - delocalization transition of the reaction front. We show an experimental realization of a dynamical localization - delocalization transition, in a system consisting of the reactants Ca2+ and Calcium Green-1 dextran, separated by a finite-sized cellulose membrane. The dynamical transition results from the continuous change in time of the flux of the penetrating species at the reaction boundary. The dynamical transition is exemplified by the kinetic behavior of the front which exhibits several time regimes, with crossover times that depend on the membrane thickness. 1) Reaction-Diffusion Front Width Anomalies in Disordered Media, I. Hecht, Y. Moran and H. Taitelbaum, Phys. Rev. E, 73, 051109 (2006). \\ 2) Dynamical Localization-Delocalization Transition of the Reaction-Diffusion Front at a Semi-Permeable Cellulose Membrane, S.H. Park, H. Peng, R. Kopelman and H. Taitelbaum, Phys. Rev. E, 75, 026107 (2007).

@incollection{statphys23_0984, abstract = {We study the front characteristics in the A+B $\rightarrow$ C reaction-diffusion system with initially-separated reactants, in two realistic cases of spatial restrictions: a) Disordered media, exemplified by two-dimensional (2D) percolation [1]. We investigate the front characteristics as a function of the disorder degree in the system, in particular close to criticality. We show that the front width exponent is {\it larger} than the mean-field (MF) exponent of 1/6, and at criticality it approaches 1/4 , which is the one-dimensional (1D) exponent. The results are discussed in the context of other systems with attenuated transport, where the front width exponent is {\it smaller} than the MF exponent. We also study the short-time behavior of the front width exponent, and discuss the validity of the scaling relations between the relevant exponents. b) Initial separation between the reactants by a finite-sized, semi-permeable wall, which allows only one reactant to diffuse through [2]. Theoretically, the ratio of the diffusive fluxes of the two species has been defined before as a control parameter and was predicted to give rise to a localization - delocalization transition of the reaction front. We show an experimental realization of a {\it dynamical} localization - delocalization transition, in a system consisting of the reactants Ca2+ and Calcium Green-1 dextran, separated by a finite-sized cellulose membrane. The dynamical transition results from the continuous change in time of the flux of the penetrating species at the reaction boundary. The dynamical transition is exemplified by the kinetic behavior of the front which exhibits several time regimes, with crossover times that depend on the membrane thickness. 1) {\it Reaction-Diffusion Front Width Anomalies in Disordered Media}, I. Hecht, Y. Moran and H. Taitelbaum, Phys. Rev. E, 73, 051109 (2006). \\ 2) {\it Dynamical Localization-Delocalization Transition of the Reaction-Diffusion Front at a Semi-Permeable Cellulose Membrane}, S.H. Park, H. Peng, R. Kopelman and H. Taitelbaum, Phys. Rev. E, 75, 026107 (2007).}, added-at = {2007-06-20T10:16:09.000+0200}, address = {Genova, Italy}, author = {Taitelbaum, H.}, biburl = {https://www.bibsonomy.org/bibtex/26026ac2fc97203ea92c13e5d4cab642a/statphys23}, booktitle = {Abstract Book of the XXIII IUPAP International Conference on Statistical Physics}, editor = {Pietronero, Luciano and Loreto, Vittorio and Zapperi, Stefano}, interhash = {17b87975f35154e6986a399306fba848}, intrahash = {6026ac2fc97203ea92c13e5d4cab642a}, keywords = {front mean-field membrane percolation reaction-diffusion statphys23 topic-4}, month = {9-13 July}, timestamp = {2007-06-20T10:16:36.000+0200}, title = {Reaction-Diffusion Front Anomalies due to Spatial Restrictions}, url = {http://st23.statphys23.org/webservices/abstract/preview_pop.php?ID_PAPER=984}, year = 2007 }