1 Introduction to the gas simulation methods The Navier-Stokes equations commonly encountered in fluid mechanics applications builds on the continuum approximation. When the ratio of the mean free path λ to the macroscopic length scale L, formalised by the non-dimensional Knudsen number Kn = λ/L, becomes large this approximation breaks down. The macroscopic length scale should be based on the l...

In this work we present a hybrid particle-grid Monte Carlo method for the Boltzmann equation, which is characterized by a significant reduction of the stochastic noise in the kinetic regime. The hybrid method is based on a first order splitting in time to separate the transport from the relaxation step. The transport step is solved by a deterministic scheme, while a hybrid DSMC-based method is ...

Planar spin transport in disordered ultrathin magnetic bilayers comprising a ferromagnet and a normal metal (typically used for spin pumping, spin Seebeck and spin-orbit torque experiments) is investigated theoretically. Using a tight-binding model that puts the extrinsic spin Hall effect and spin swapping on equal footing, we show that the nature of spin-orbit coupled transport dramatically de...

We investigate through molecular dynamics the transition from Knudsen to molecular diffusion transport towards two-dimensional absorbing interfaces with irregular geometry. Our results indicate that the length of the active zone decreases continuously with density from the Knudsen to the molecular diffusion regime. In the limit where molecular diffusion dominates, we find that this length appro...

In the framework of collection and identification of bolete fungi of Iran, one specimen from the genus Strobilomyces was collected and identified as Strobilomyces strobilaceus (Scop.) Berk., based on Knudsen & Vesterholt (2008).

The time evolution of the flow parameters in a system where gas is expanded from a high pressure chamber through a tube toward a low pressure chamber is investigated. During the process, the pressure in the two chambers is changing in the opposite direction, while the flow rate is reduced until the system reaches its equilibrium state. Rarefied conditions may be present. Based on the observatio...