We consider overdamped Brownian dynamics in a periodic potential with temporally oscillating amplitude. We analyze the transport which shows effective diffusion enhanced by the oscillations and derive approximate expressions for the diffusion coefficient. Furthermore we analyze the effect of the oscillating potential on the transport if additionally a constant force is applied. We show the exis...

By analytical methods we study the large time properties of the solution of a simple one-dimensional model of stochastic Stokes’ drift. Semi-explicit formulae allow us to characterize the behaviour of the solutions and compute global quantities such as the asymptotic speed of the center of mass or the effective diffusion coefficient. Using an equivalent tilted ratchet model, we observe that the...

We present the dynamic scaling behavior for the specific viscosity and diffusion coefficient of a single membrane and membranes with nonzero concentration in solution. Starting from the membrane free energies, we derive their Langevin equations. The corresponding Kirkwood diffusion equation, describing the time evolution in configuration space, contains two kinds of time scales that are separat...

This paper presents the experimental results of utilizing a flexible thin-film membrane as a passive barrier to radon gas diffusion. Nine commercially available membranes of various compositions and thicknesses were evaluated as retardant to radon gas diffusion. The radon gas concentration ratios across the thin-film membranes alone and in combination with an adjacent concrete sample (effective...

This document provides definitions of terms and processes which are used in describing the migration of host and foreign species through solid materials. Both the phenomenological theory of diffusion and the detailed atomistic mechanisms by which atom transport occurs are treated. Also included are the various types of gradients such as electrical, chemical, thermal and mechanical, which provid...

In many cell-signaling pathways, information is transmitted by the diffusion of messenger molecules. Diffusion coefficients characterize the messenger's spatial range and the characteristic times of signal propagation. Inside cells, particles usually diffuse in the presence of immobile binding sites (or traps). It is well known that binding to traps results in an effective diffusion coefficient...

Traditional error diffusion algorithm has been generally proved as an effective method for digital image halftoning, but it cannot generate a visually pleasing output on asymmetric-resolution output planes where vertical and horizontal resolution is not equal. In this sketch, we designed an optimization process to search for the diffusion coefficients for such output planes. Integrated within t...