The dynamics of charged Coulomb grains in a plasma is numerically and analytically investigated. Analogous to recent experiments, it is assumed that the grains are trapped in an external parabolic field. Our simulations are based on a Langevin model, where the grain-plasma interaction is realized by a velocity-dependent friction coefficient and a velocity-independent diffusion coefficient. In a...

1 IMETUM und Physik Department, TUM, Boltzmannstrasse 11, 85748 Garching. 2 Ernst-Berl Institut für Makromolekulare Chemie, TU Darmstadt, Petersenstrasse 22, 64287 Darmstadt, Germany. Fig. 1: Observed nanoscale friction mechanisms. A single polymer molecule at a solidliquid interface can respond in different ways to a lateral external force, here exerted by an AFM cantilever tip (depicted in ye...

The energy dissipation in the contact regions between solids in sliding contact can result in high local temperatures which may strongly effect friction and wear. This is the case for rubber sliding on road surfaces at speeds above 1 mm s(-1). We derive equations which describe the frictional heating for solids with arbitrary thermal properties. The theory is applied to rubber friction on road ...

objective: to investigate the friction of rabbit’s knee joint with designed pendulum friction tester to diagnose and evaluate different pathological and therapeutic conditions following haemarthrosis, osteoarthritis, and other joint disorders. materials and methods: friction coefficient of 10 adult male albino rabbit’s joint (5 right and 5 left knees) weighted 1.59 ± 0.27 kg, after designing a...

Because of properties such as heat stability and good lubrication, silicones can provide a reduction of the dynamic coefficient of friction, reducing the risk of fiber melting and breakage during production. Low viscosity polydimethylsiloxane (PDMS) is generally used in combination with solid particles (e.g., those made of magnesium stearate), as this also reduces the static coefficient of fric...

OBJECTIVE The objective of this study is to examine ground kinetics early in stance while walking on a contaminated surface and assess the potential of kinetics to quantify risk of slipping. BACKGROUND Prior studies of slipping have dismissed early ground kinetic data,and therefore no prior literature has been able to assess the viability of using these data to quantify slip potential. METH...

In many sliding systems consisting of solid object on a solid substrate under dry condition, the friction force does not depend on the apparent contact area and is proportional to the loading force. This behaviour is called Amontons' law and indicates that the friction coefficient, or the ratio of the friction force to the loading force, is constant. Here, however, using numerical and analytica...

In this investigation three effects are included in a recently developed scale-dependent multi-asperity model of elastic contact and friction. First, a Weibull distribution of asperity heights is used, which allows the skew and kurtosis to be varied, but not independently of each other. Second, the effect of non-constant radii of curvature of the asperity summits, with the curvature varying wit...

We have characterized the frictional properties of nanostructured carbon films grown by supersonic cluster beam deposition via an atomic force-friction force microscope (AFM-FFM). The experimental data are discussed on the basis of a modified Amonton's law for friction, stating a linear dependence of friction on load plus an adhesive offset accounting for a finite friction force in the limit of...

the course of consecutive experiments in this report aimed to a research or introductory identification about mechanical and acoustical properties of maple (acer velutinum) wood. studied factors were included quality factor (due to internal friction), acoustic coefficient, acoustical conversion efficiency as well as the modulus of elasticity (young’s modulus) which they were all accomplished us...