The grain size effects on the bremsstrahlung emission spectrum due to nonrelativisitc electrondust grain collisions are investigated in dusty plasmas. Using the Born approximation for the initial and final states of the projectile electron, the bremsstranhlung radiation cross section is obtained as a function of the grain size, dust charge, Debye radius, collision energy, and radiation photon e...

large areas of iran are under the influence of wind erosion thus it is important that we recognize three zones ofremoval, transportation and deposition. the deposition zone is very important due to more damages and tangibleeffects. in this study we try to obtain a comprehensive idea to persian desert with use of laboratory facilities, remotesensing, gis and field surveying. we survey 28 ergs in...

When load is applied to fcc nanograins, leading partial dislocations nucleate at grain boundary steps and propagate into the grain, leaving stacking faults behind. The extent to which these faults expand before a trailing partial is emitted generally does not equal the equilibrium separation distance of the corresponding full dislocation. Here we use a density functional theory – phase field di...

An inverse Hall–Petch effect has been observed for nanocrystalline materials by a large number of researchers. This effect implies that nanocrystalline materials get softer as grain size is reduced below a critical value. Postulated explanations for this behavior include dislocation-based models, diffusion-based models, grain-boundary-shearing models and two-phase-based models. In this paper, w...

Abstract Solute accumulation/depletion in the liquid around a growing solid particle during solidification of metallic melts creates constitutionally supercooled (CS) zone that has significant effect on final solidified grain structure. In this paper, we introduce two mechanisms related to CS affect size: one is initiation free (GIFZ) describes inability nucleant particles located for and other...

the effect of grain size, tailwater depth and grain froude number on local scour caused by submerged horizontal jets issuing below a sluice gate was investigated. noncohesive sediments with two gradations downstream of a horizontal apron were used in the experiments. the experiments were carried out at different inflow froude numbers and a range of tailwater depth from low to high submergence. ...