We report measurements of nonequilibrium noise in a diffusive normal metal-superconductor (N-S) junction in the presence of both dc bias and high-frequency ac excitation. We find that the shot noise of a diffusive N-S junction is doubled compared to a normal diffusive conductor. Under ac excitation of frequency nu the shot noise develops features at bias voltages |V| = hnu/(2e), which bear all ...

Diffusive-ballistic heat conduction of finite-length single-walled carbon nanotubes has been studied by means of non-equilibrium molecular dynamics simulations. The length-dependence of thermal conductivity is quantified for a range of nanotube-lengths up to a micrometer at room temperature. A gradual transition from nearly pure ballistic to diffusive-ballistic heat conduction was identified fr...

In this paper we construct numerical schemes to approximate linear transport equations with slab geometry by diffusion equations. We treat both the case of pure diffusive scaling and the case where kinetic and diffusive scalings coexist. The diffusion equations and their data are derived from asymptotic and layer analysis which allows general scattering kernels and general data. We apply the ha...

A common approach for parameterising eddy transport of passive tracers by mesoscale eddies in the ocean is invoking a tensor. The symmetric part this tensor, diffusion quantifies diffusive tracer transport. Recent studies have diagnosed opposite-signed eigenvalues (diffusivities) tensor from eddy-resolving simulations, while all current parameterisations implement only positive diffusivities. F...

a simple mathematical model of steady state  oxygen distribution subject to diffusive transport and non- linear uptake in a retinal cylinder has been developed. the approximate analytical solution to a reaction- diffusion equation are obtained by using series expansions. the computational results for the scaled variables are presented through graphs. the effect of the important parameters (1) d...

A sequence of two- and three-dimensional simulations are conducted for the double-diffusive convection (DDC) flows in diffusive regime subjected to an imposed shear. For a wide range control parameters, sufficiently strong perturbation conductive initial state, staircase-like structures spontaneously develop, with relatively well-mixed layers separated by sharp interfaces enhanced scalar gradie...

It is well known that on long time scales the behaviour of tracer particles diffusing in a cellular flow is effectively that of a Brownian motion. This paper studies the behaviour on “intermediate” time scales before diffusion sets in. Various heuristics suggest that an anomalous diffusive behaviour should be observed. We prove that the variance on intermediate time scales grows like O( √ t). H...

In this paper we further explore and apply our recent anti-diffusive flux corrected high order finite difference WENO schemes for conservation laws [18] to compute the Saint-Venant system of shallow water equations with pollutant propagation, which is described by a transport equation. The motivation is that the high order anti-diffusive WENO scheme for conservation laws produces sharp resoluti...

In this paper we construct numerical schemes to approximate linear transport equations with slab geometry by one-dimensional diffusion equations. We treat both the case of pure diffusive scaling and the case where kinetic and diffusive scalings coexist. The diffusion equations and their data are derived from asymptotic and layer analysis which allows general scattering kernels and general data....

Angular momentum transport must have occurred in the Sun’s radiative zone to explain its current solid body rotation. We survey the stability of the early Sun’s radiative zone with respect to diffusive rotational instabilities, for a variety of plausible past configurations. We find that the (faster rotating) early Sun was prone to rotational instabilities even if only weak levels of radial dif...