We consider a mathematical model which describes the frictional unilateral contact between a thermo-piezoelectric body and a rigid electrically conductive foundation. The thermo-piezoelectric constitutive law is assumed to be nonlinear and the contact is modeled with the Signorini condition, the nonlocal Coulomb friction law with slip dependent friction coefficient and the regularized electrica...

Simultaneous measurements of the curves for wear versus distance, wear rate versus distance, and coefficient of friction versus distance were performed in situ to distinguish the transition from severe running-in wear to mild wear. The effects of the initial surface roughness on the severe running-in wear volume were investigated. Disk-on-plate friction and wear tests were carried out with SUS3...

a new dynamic friction model for modeling of elliptical vibration assisted turning (evat) was developed in this research. the periodic change of the friction force direction is known to be one of the most important causes of this phenomenon. in modeling of machining processes (including the evat process), static coulomb friction model was employed by most of the researchers. because of the peri...

We suggest a “minimal model” for the 3D turbulent energy spectra in superfluids, based on their two-fluid description. We start from the Navier-Stokes equation for the normal fluid and from the coarse-grained hydrodynamic equation for the superfluid component (obtained from the Euler equation for the superfluid velocity after averaging over the vortex lines) and introduce a mutual friction coup...

Snoek relaxation in bcc crystals is the delayed strain response to an applied stress resulting from interaction of interstitial atoms with field. It responsible for peak observed internal friction measurements ferrite. However, although martensite carbon supersaturated, several authors denied possibility bct-martensite. We investigated this matter by means Monte Carlo simulations and mean-field...

Original scientific paper In this paper, the results of investigations of the temperature field distribution and tool wearing during C60 steel turning are presented. Abrasive wear resistance tests were carried out for cutters made of low-alloy high-speed steel. Steel samples were heat treated, and then were subjected to ion nitriding, TiN coating, or to complex treatment. The influence of cutti...

The solvation dynamics and local orientational friction for a series of four ionic liquids have been probed using coumarin 153 (C153) as a function of temperature. These ionic liquids are comprised of nonaromatic organic cations paired with a common anion, bis(trifluoromethylsulfonyl)imide (NTf(2)-). The specific liquids are as follows: N-methyl-tri-N-butylammonium NTf(2)- (N(1444)+/NTf(2)-), N...

A theoretical analysis is performed to study the flow and heat transfer characteristics of magnetohydrodynamic mixed convection flow of a micropolar fluid past a stretching surface with slip velocity at the surface and heat generation absorption . The transformed equations solved numerically using the Chebyshev spectral method. Numerical results for the velocity, the angular velocity, and the t...

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 ...

The effect of an asymmetric distribution of asperity heights is accounted for in a recently developed scale-dependent multiasperity model of contact and friction. A Weibull distribution of asperity heights is used which allows the skew and kurtosis to be varied, but not independently of each other. The contact and friction model used includes the effects of adhesion and of scale-dependent frict...