We conducted experiments in which steel and silicon or quartz are clamped together. Even with the smallest tangential forces we could apply, we always found reproducible sliding motions on the nanometer scale. The velocities we study are thousands of times smaller than in previous investigations. The samples first slide and then lock up even when external forces hold steady. One might call the ...

Liquid water is pushed through flow channels of fuel cells, where one surface is a porous carbon electrode made up of carbon fibers. Water drops grow on the fibrous carbon surface in the gas flow channel. The drops adhere to the superficial fiber surfaces but exhibit little penetration into the voids between the fibers. The fibrous surfaces are hydrophobic, but there is a substantial threshold ...

this study was conducted to investigate some moisture-dependent engineering properties of russian olive fruit including fruit dimensions, one thousand seed mass, surface area, sphericity, bulk and true density, angle of sliding and static friction coefficient against different surfaces. the physical properties of russian olive fruit were evaluated as a function of moisture content in the range ...

One of the main factors that cause to quality loss for fresh fruit market apples is bruise damage. Amongst the factors that affect apple sensitivity to bruising, major one is drop height and area profile during the impact. In the present study, four Iranian apple varieties consisted of Atirli, Kapak, Kowse and Paiez that were selected and 100 fruits of each variety were picked up, then apples w...

The complexity of the frictional dynamics at the microscopic scale makes difficult to identify all of its controlling parameters. Indeed, experiments on sheared elastic bodies have shown that the static friction coefficient depends on loading conditions, the real area of contact along the interfaces and the confining pressure. Here we show, by means of numerical simulations of a 2D Burridge-Kno...

This contribution deals with numerical solution of shape optimization problems in frictional contact mechanics. The state problem in our case is given by 2D static Signorini problems with Tresca friction and a solution-dependent coefficient of friction. A suitable Lipschitz continuity assumption on the coefficient of friction is made, ensuring unique solvability of the discretized state problem...

One of the main factors that cause to quality loss for fresh fruit market apples is bruise damage. Amongst the factors that affect apple sensitivity to bruising, major one is drop height and area profile during the impact. In the present study, four Iranian apple varieties consisted of Atirli, Kapak, Kowse and Paiez that were selected and 100 fruits of each variety were picked up, then apples w...

Investigation of the stationary load-deflection behaviour of tyres reveals many details of the structure and the rubber to road friction properties. These characteristics are fundamental to the understanding of the behaviour of both the stationary and the rolling tyre. In connection with racing, tyre static stiffness characteristics are of interest as they reflect on the controllability of the ...