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 ...

In this work, the Z-average, effective, apparent diffusion coefficients and their poly-dispersity indexes were investigated for dilute poly-disperse homogeneous spherical particles in dispersion where the Rayleigh-Gans-Debye approximation is valid. The results reveal that the values of the apparent and effective diffusion coefficients at a scattering angle investigated are consistent and the di...

This paper presents an updated empirical assessment of the relative effectiveness of intra-platform and inter-platform competition in terms of broadband diffusion in Europe between 2003 and 2010. It relies on an econometric analysis of 18 European countries. To approximate two forms of competition within a same platform, we distinguish between service-based access and facility-based access. The...

This work explores different particle-based approaches to the simulation of one-dimensional fractional sub-diffusion equations in unbounded domains. We rely on smooth particle approximations, and consider four methods for estimating the fractional diffusion term. The first method is based on a direct differentiation of the particle representation; it follows the Riesz definition of the fraction...

The salivary glands of the dipteran Chironomus tentans provide an elegant model system for the analysis of specific messenger ribonucleoprotein particles, the Balbiani Ring (BR) mRNP. BR mRNP particles contain long RNA transcripts of roughly 35-40 kb in size which possess a highly repetitive sequence. The diameter of the granular BR mRNP particles is around 50 nm and their geometry was meanwhil...

Multiple particle tracking (MPT) methodology was used to dissect the impact of nanoparticle surface charge and size upon particle diffusion through freshly harvested porcine jejunum mucus. The mucus was characterised rheologically and by atomic force microscopy. To vary nanoparticle surface charge we used a series of self-assembly polyelectrolyte particles composed of varying ratios of the nega...