The hot gases produced by the internal combustion engines passes through the exhaust valve and causes high temperatures in the exhaust valve and its seat. To avoid damaging the exhaust valve, heat must be transferred from the valve to its seat during the contact they make at the opening and closing cycle. Heat transfer rate from the exhaust valve to its seat is a function of many factors. One o...

a modified model has been analytically developed to describe the induction time of an elliptic air bubble in contact with an elliptic hydrophobic oil droplet. the role of hydrophobicity was revealed in the slippage of liquid over the surfaces of bubble and droplet. in this condition, the analytical relationships for pressure distribution and consequently hydrodynamic resistance force through th...

Since, sports activities are likely to be changes in various parameters of plantar pressure distribution during walking to create, This study compared patterns of plantar pressure distribution between right and left feet and their relationship with anthropometric parameters. 10 elite wrestler with the average and standard deviation of age: 23.6±3.33 yrs, height: 173.5±7.67 cm and mass: 83.3±21....

coeffcient of  friction  (cof)  for  rubber parts  is one of  the key parameters in their interaction with solid rough surfaces (micrometer to millimeter scales),  such  as  tire-road  interactions. cof  of  rubber  depends  on  viscoelastic properties of rubber, roughness characteristics of the counter-part surface, and process variables such as contact nominal pressure and sliding speed. due ...

A new model is developed that considers the effect of roughness on the elastic contact of spherical bodies. A general pressure distribution is proposed that encompasses the contact of rough spheres and yields the Hertzian theory for ideally smooth surfaces. A new parameter, nondimensional maximum contact pressure, is introduced and it is shown that this is the key parameter that controls the co...