We studied adjustments of digit forces to changes in the friction. The subjects held a handle statically in a three-digit grasp. The friction under each digit was either high or low, resulting in eight three-element friction sets (such grasps were coined the grasps with complex friction pattern). The total load was also manipulated. It was found that digit forces were adjusted not only to the s...

This paper deals with the full discretization of quasistatic 3D Signorini problems with local Coulomb friction and a coefficient of friction which may depend on the solution. After a time discretization we obtain a system of static contact problems with Coulomb friction. Each of these problems is solved by the T-FETI domain decomposition method used in auxiliary contact problems with Tresca fri...

We demonstrate measurement and control of single-asperity friction by using cantilever probes featuring an in situ solid-state heater. The heater temperature was varied between 25 and 650 °C (tip temperatures from 25 ± 2 to 120 ± 20 °C). Heating caused friction to increase by a factor of 4 in air at ∼ 30% relative humidity, but in dry nitrogen friction decreased by ∼ 40%. Higher velocity reduce...

Metal-on-ultra-high molecular weight polyethylene (UHMWPE) total hip replacements have been the most popular and clinically successful implants to date. However, it is well documented that the wear debris from these prostheses contributes to osteolysis and ultimate failure of the prosthesis, hence alternative materials have been sought. A range of 28 mm diameter bearings were investigated using...

this paper presents a three-dimensional numerical investigation carried out in turbulent forced convection in a tube with helical ribs. enhancement of heat transfer using helically corrugated tubes has beenstudied experimentally by many researchers but there exist a few published numerical analyses results. the paper also introduces the results of heat transfer and friction factor data for inco...

We study the rise dynamics of a large particle in a granular bed under vertical vibration using molecular dynamics simulations. Systematic variation of the particle properties and external wall friction in the simulations shows that the large particle rising is very sensitive to external wall friction. The dynamical response of the granular bed with wall friction is shown to include an expansio...

We investigate the effect of a density gradient on Chandrasekhar’s dynamical friction formula based on the method of 2-body encounters in the local approximation. We apply these generalizations to the orbit evolution of satellite galaxies in Dark Matter haloes. We find from the analysis that the main influence occurs through a position-dependent maximum impact parameter in the Coulomb logarithm...

In this study, the three-dimensional magnetohydrodynamic (MHD) boundary layer of stagnation-point flow in a nanofluid was investigated. The Navier–Stokes equations were reduced to a set of nonlinear ordinary differential equations using a similarity transform. The similarity equations were solved for three types of nanoparticles: copper, alumina and titania with water as the base fluid, to inve...

A three-dimensional numerical simulation of flow through serpentine microchannels with designed roughness in form of obstructions placed along the channels walls is conducted here. CFD-ACE+ is used for the numerical simulations. The effect of the roughness height (surface roughness), geometry, Reynolds number on the friction factor is investigated. It is found that the friction factor increases...

In order to increase the efficiency of the conveyance of the granular solids, a new experimental set-up is designed. The test rig has longitudinal trapezoidal slots in its conveying pipes. Through experimentation, a correlation for friction factor in terms of solid mass flow rate, fluid flow rate and Froude number is presented. It is shown that the mixture friction factor for pipes with inn...