4 research outputs found
Front formation in a ballistic annihilation model
We study a simple one-dimensional model of ballisticaly-controlled
annihilation in which the two annihilating species are initially spatially
separated. The time dependent properties of the annihilation front are exactly
derived. It is shown that the front wanders in a brownian fashion around its
average value.Comment: Typeset using Latex, with Elsevier macros (elsart); 17 pages with one
Latex figure and two Encapsulated Postscript figures (need epsf
Band Formation during Gaseous Diffusion in Aerogels
We study experimentally how gaseous HCl and NH_3 diffuse from opposite sides
of and react in silica aerogel rods with porosity of 92 % and average pore size
of about 50 nm. The reaction leads to solid NH_4Cl, which is deposited in thin
sheet-like structures. We present a numerical study of the phenomenon. Due to
the difference in boundary conditions between this system and those usually
studied, we find the sheet-like structures in the aerogel to differ
significantly from older studies. The influence of random nucleation centers
and inhomogeneities in the aerogel is studied numerically.Comment: 7 pages RevTex and 8 figures. Figs. 4-8 in Postscript, Figs. 1-3 on
request from author