We want to investigate the stochastic parameters, drift and diffusion, in Fényes’ and Nelson’s approach of stochastic mechanics. In contrast to the postulate of a constant diffusion parameter, we consider coordinate dependent alternatives. Therefore, we assume that the trajectory of a particle can be described by a continuous stochastic process with spaceand/or time-dependent diffusion. For an ...

We investigate the ensemble and time averaged mean squared displacements for particle diffusion in a simple model for disordered media by assuming that the local diffusivity is both fluctuating in time and has a deterministic average growth or decay in time. In this study we compare computer simulations of the stochastic Langevin equation for this random diffusion process with analytical result...

The solution of the non-linear diffusive shock acceleration problem, where the pressure of the non-thermal population is sufficient to modify the shock hydrodynamics, is widely recognized as a key to understanding particle acceleration in a variety of astrophysical environments. We have developed a Monte Carlo technique for self-consistently calculating the hydrodynamic structure of oblique, st...

Particle-based Brownian dynamics simulations offer the opportunity to not only simulate diffusion of particles but also the reactions between them. They therefore provide an opportunity to integrate varied biological data into spatially explicit models of biological processes, such as signal transduction or mitosis. However, particle based reaction-diffusion methods often are hampered by the re...

A wide-field localized surface plasmon resonance (LSPR) imaging method using a liquid crystal tunable filter is used to measure the scattering spectra of multiple Ag nanoparticles in parallel. This method provides the ability to characterize moving Ag nanoparticles by measuring the scattering spectra of the particles while simultaneously tracking their motion. Consequently, single-particle diff...

Diffusion in a comb-like structure, formed by a main cylindrical tube with identical periodic dead ends of cylindrical shape, occurs slower than that in the same system without dead ends. The reason is that the particle, entering a dead end, interrupts its propagation along the tube axis. The slowdown becomes stronger and stronger as the dead end length increases, since the particle spends more...

The properties of one-particle and particle-pair diffusion in rotating and stratified turbulence are studied by applying the Rapid Distortion Theory to a Kinematic Simulation of the Boussinesq equation with a Coriolis term. Scalings for oneand two-particle horizontal and vertical diffusions in purely rotating turbulence are proposed for small Rossby numbers. Particular attention is given to the...

Segregation of granular materials composed of different-sized particles has important repercussions in various industrial processes and natural phenomena, but predicting size segregation remains a challenging problem. To address this problem, we have developed a theoretical model that captures the interplay between advection, segregation, and diffusion in size bidisperse granular materials. The...

An expression for the single-particle thermal diffusion coefficient of a charged colloidal sphere is derived on the basis of force balance on the Brownian time scale in combination with thermodynamics. It is shown that the single-particle thermal diffusion coefficient is related to the temperature dependence of the reversible work necessary to build the colloidal particle, including the core, t...

Concentrated suspensions may shear thin when the suspended particles form planar sheets that slide over one another with less friction than if the particles are randomly distributed. In a naive model the suspension is described by a mean effective viscosity and particles that collide with each other redistribute the mean density in the shearing direction. This leads to a diffusion equation for ...