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 ...

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...

due to medical and dietary properties of the plantago major l. seed, it is necessary to know engineering properties in order to design post harvest equipments. engineering properties of plantago major l. seed was determined only at the moisture content of 7.98% dry basis, because of it produces mucilaginous components when it is soaked in water. the average of length, width, surface area, spher...

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 ...

a knowledge of physical properties of sunflower seed is essential for the design and development of such processing equipment as handling, separating, dehulling and storing. in this research, physical properties of sunflower seed, (azargol variety as a case of study, was investigated at various moisture contents (3-14% d.b) and in three categories of big, average and small sizes samples. the re...

many studies have been conducted focusing on the effects of friction coefficient or texture depth on the highway accident risk. however, combined effects of these parameters have not been still addressed. in this research the interaction between friction coefficient, texture depth and accident rate in 30 freeway sections were examined. the accident data were gathered and an apparatus was design...

We study the dependence of friction on surface roughness, sliding velocity, and temperature. Expanding on the classic treatment of Greenwood and Williamson, we show that the fractal nature of a surface has little influence on the real area of contact and the static friction coefficient. A simple scaling argument shows that the static friction exhibits a weak anomaly mu ~ A(0)(-chi/4), where A0 ...