Publications by Year: 1986

1986
Weitz, D. A. ; Lin, M. Y. Dynamic scaling of cluster-mass distributions in kinetic colloid aggregation. Physical Review Letters 1986, 57, 2037-2040. Publisher's VersionAbstract

The cluster-mass distributions produced in the kinetic aggregation of aqueous gold colloids are measured over an extended range of masses for two limiting kinetic regimes, diffusion-limited (DLA) and reaction-limited (RLA) aggregation. Markedly different distributions are found, with DLA having a peaked distribution, while RLA has a power-law distribution. In both cases the distributions are shown to exhibit dynamic scaling, as has recently been predicted. The data are interpreted with the Smoluchowski equations, and are used to determine the form of the appropriate kernel for each regime.

weitz1986.pdf
Stokes, J. P. ; Weitz, D. A. ; Gollub, J. P. ; Dougherty, A. ; Robbins, M. O. ; Chaikin, P. M. ; Lindsay, H. M. Interfacial stability of immiscible displacement in a porous-medium. Physical Review Letters 1986, 57, 1718-1721. Publisher's VersionAbstract
We study patterns formed by the viscous fingering instability in a porous medium. The wetting properties of the medium have a profound influence on the width of the individual fingers and consequently on the shape of the overall pattern. If the displaced fluid preferentially wets the medium, the finger width is comparable to the pore size, independent of other parameters. In contrast, if the displacing fluid preferentially wets the medium, the finger width is much larger than the pore size, and, when normalized by the square root of the permeability, is found to scale with the capillary number approximately as N−12Ca.
stokes1986.pdf
Dimon, P. ; Sinha, S. K. ; Weitz, D. A. ; Safinya, C. R. ; Smith, G. S. ; Varady, W. A. ; Lindsay, H. M. Structure of aggregated gold colloids. Physical Review Letters 1986, 57, 595-598. Publisher's VersionAbstract
We report a high-resolution, small-angle x-ray study of aggregated gold colloids over the range 0.0003 to 0.08 Å−1. We are able to fit our data with a simple model that correctly accounts for nonfractal short-range order with a crossover to long-range fractal correlations. This provides new information on the structure of real aggregates, and new insight into the aggregation processes which lead to their formation.
dimon1986.pdf