Most plant and mammalian tissue lipids contain fatty acids with a carbon chain longer than 14 atoms. However, milk lipids from several species like ruminants and rodents (Jenness, 1974), seed lipids from certain plants like coconuts (Child, 1974) and Cuphea (Graham & Kleiman, 1985) and lipids from several insects (AddaeMensah & Cameron, 1978) and from some bird glands (Downing, 1976; Jacob, 197...

Rarefied gas flows in thin film slider bearings are studied in a wide range of Knudsen numbers (Kn) at low Mach number (Ma) with the objective of developing simple physics-based semi-analytical models. A recently developed modified slip boundary condition for steady plane Couette flows and a generalized high-order velocity slip boundary condition, developed and validated earlier for pressure-dr...

In this work, for better understanding of drug delivery systems, blood flow over a ceramic nanoparticle is investigated through microvessels. Drug is considered as a nanoparticle coated with the rigid ceramic. Due to the low characteristic size in the microvessel, the fluid flow is not continuum and the no-slip boundary condition cannot be applied. To solve this problem lattice Boltzmann method...

The approximate solution of the Boltzmann transport equation via Galerkin-type series expansion methods leads to a system of first order differential equations in space and time for the expansion coefficients. This system is extremely stiff close to the fluid dynamical regime (for small Knudsen numbers), and exhibits a mildly dispersive behavior, due to the acceleration of waves by the external...

We investigate the constant-wall-temperature convective heat-transfer characteristics of a model gaseous flow in two-dimensional micro and nano-channels under hydrodynamically and thermally fully developed conditions. Our investigation covers both the slip-flow regime 0<Kn<0.1, and most of the transition regime 0.1,Kn<10, where Kn, the Knudsen number, is defined as the ratio between the molecul...

We derive the continuum equations and boundary conditions governing phonon-mediated heat transfer in the limit of a small but finite mean-free path from the asymptotic solution of the linearized Boltzmann equation in the relaxation time approximation. Our approach uses the ratio of the mean-free path to the characteristic system length scale, also known as the Knudsen number, as the expansion p...

1. Introduction Gas diffusion in mesoporous media is often in the Knudsen regime, cross sections of the pores being considerably smaller than the intrinsic molecular mean free path. Coppens [1] predicted the effect of fractal wall roughness on Knudsen self-diffusivity K D in a channel. A " trapping " process was identified as the cause of reduction of

This paper describes the evaluation of four types of porous ceramics for use as thermal transpiration materials in Knudsen pumps that operate at atmospheric pressure. Knudsen pumps are motionless gas pumps that utilize thermal transpiration along a channel or a set of channels; the channels must have a temperature gradient and must constrain the flow to remain within the free molecular or trans...

Traditionally, acoustics is concerned with the treatment of the fluid as a continuum using macroscopic quantities such as velocity and pressure as dependent variables. However, the continuum model breaks down for Knudsen numbers (Kn) greater than roughly 0.05, where Kn is defined as the ratio of mean free path to wavelength. Particle methods are necessary for, but not limited to, problems with ...

Laser induced thermal desorption of Xe atoms into vacuum from a metal surface following the nano-second pulsed laser heating was investigated by the time-of-flight (TOF) measurement. The desorption flow was studied at a wide range of desorption flux by varying the initially prepared Xe coverage Θ (1 ML = 4.5 × 10(18) atoms/m(2)). At Θ = 0.3 ML, the TOF of Xe was well represented by a Maxwell-Bo...