We present an ab initio study of the electronic structure of SnO. Density functional theory in the local density approximation (DFT-LDA) is used in conjunction with carefully tested smooth pseudopotentials. Total energies and charge densities are calculated and analysed as a function of the atomic geometry, with a particular emphasis on the importance of low-chargedensity contributions to the i...

Friction welding is a type of solid state where the process carried out in phase to combine various types ferrous and non-ferrous metals that cannot be welded by fusion method but for different results are less than optimal due cracks on surface differences mechanical properties cause result brittle, therefore an interlayer used. In this study, observations were made joint friction using dissim...

Continued exploration of the Moon and Mars will call for mobile robots that are increasingly capable in regolith; not only traversing it without getting stuck, but also manipulating and shaping it to suit mission needs. This work distinguishes issues governing performance of regolith operations, based on tasks motivated by preparatory site work for lunar outposts. Payload ratio (pound-forpound ...

b = a length L c = the cohesion intercept M L T Ip = the plasticity index P = a force M L T u = the pore fluid pressure ML T θ = an angle Angle μ1 = shear strength reduction factor related to time effects μ2 = shear strength reduction factor related to fissuring σ = the normal stress on a plane M L T τ = the shearing stress on a plane M L T φ = the angle of internal friction Angle ψ = an angle ...

the friction properties of granular materials play an important role in the determination of specifications for designing hoppers, transporting passages, dryers, silos and machines through which grain flows. in this study, the angle of repose and internal friction coefficient were determined for three common wheat varieties (sardary, gaspard and saysoter) at four moisture contents (12, 15, 18, ...

This paper presents the results of modeling tests of the Effect of Confinement Pressure on footing bearing capacity of two kinds of square and strip footing. Footings bearing capacity depends upon many factors including soil kind, depth, form and kind of loading. Soil behavior is variable regarding the kind of loading and the kind of deformations in that can have great importance in the amount ...

Frictional properties of soft elastomers have been in question for over half of a century. Early studies on natural rubber originated for the sole purpose of tabulating properties for bulk consumer applications, such as viscoelastic adhesives, tires, and windshield wipers, to name a few. Empirical tabulation of frictional properties persisted until the early 1950’s, when Roth et al. and Thirion...

We describe interlayer force measurements during prolonged, cyclic telescoping motion of a multiwalled carbon nanotube. The force acting between the core and the outer casing is modulated by the presence of stable defects and generally exhibits ultralow friction, below the measurement limit of 1.4 x 10(-15) N/atom and total dissipation per cycle lower than 0.4 meV/atom. Defects intentionally in...