Temperature dependent viscosity and thermal conductivity effects on combined heat and mass transfer in MHD three-dimensional flow over a stretching surface with Ohmic heating

An analysis has been carried out to obtain the flow, heat and mass transfer characteristics of a viscous electrically conducting fluid having temperature dependent viscosity and thermal conductivity past a continuously stretching surface, taking into account the effect of Ohmic heating. The flow is subjected to a uniform transverse magnetic field normal to the plate. The resulting governing three-dimensional equations are transformed using suitable three-dimensional transformations and then solved numerically by using fifth order Runge–Kutta–Fehlberg scheme with a modified version of the Newton–Raphson shooting method. Favorable comparisons with previously published work are obtained. The effects of the various parameters such as magnetic parameter M, the viscosity/temperature parameter θ _r , the thermal conductivity parameter S and the Eckert number Ec on the velocity, temperature, and concentration profiles, as well as the local skin-friction coefficient, local Nusselt number, and the local Sherwood number are presented graphically and in tabulated form.     

Quasi-isochoric ion beam heating using dynamic confinement in spherical geometry for X-ray scattering experiments in WDM regime

Extreme states of matter such as Warm Dense Matter “WDM” and Dense Strongly Coupled Plasmas “DSCP” play a key role in many high energy density experiments, however, creating WDM and DSCP in a manner that can be quantified is not readily feasible. In this paper, isochoric heating of matter by intense heavy ion beams in spherical symmetry is investigated for WDM and DSCP research: the heating times are long (100 ns), the samples are macroscopically large (millimeter-size) and the symmetry is advantageous for diagnostic purposes. A dynamic confinement scheme in spherical symmetry is proposed which allows even ion beam heating times that are long on the hydrodynamic time scale of the target response. A particular selection of low-Z target tamper and X-ray probe radiation parameters allows to identify the X-ray scattering from the target material and use it for independent charge state measurements Z* of the material under study.     

Scaling group transformation for MHD boundary layer flow over permeable stretching sheet in presence of slip flow with Newtonian heating effects

Taking into account the slip flow effects, Newtonian heating, and thermal radiation, two-dimensional magnetohydrodynamic （MHD） flows and heat transfer past a permeable stretching sheet are investigated numerically. We use one parameter group transformation to develop similarity transformation. By using the similarity transformation, we transform the governing boundary layer equations along with the boundary conditions into ordinary differential equations with relevant boundary conditions. The obtained ordinary differential equations are solved with the fourth-fifth order Runge-Kutta- Fehlberg method using MAPLE 13. The present paper is compared with a published one. Good agreement is obtained. Numerical results for dimensionless velocity, temperature distributions, skin friction factor, and heat transfer rates are discussed for various values of controlling parameters.     

Dynamic shear-strain localization and inclusion effects in lath martensitic steels subjected to high pressure loads

A three-dimensional multiple-slip dislocation-density based crystalline formulation, specialized finite-element formulations, and specialized Voronoi tessellations adapted to martensitic orientations, were used to investigate shear-strain localization, and dislocation-density evolution in martensitic microstructures under dynamic compressive loading conditions. The formulation is based on accounting for variant morphologies and orientations, secondary-phase structures, and initial dislocations-densities that are uniquely inherent to martensitic microstructures. The effects of strain rate and inclusions on the evolution of shear-strain localization were investigated. The analysis indicates that variant morphology and orientations have a direct consequence on dislocation-density accumulation and inelastic localization in martensitic microstructures, and that lath directions, orientations, and arrangements are critical characteristics of high-strength martensitic dynamic behavior. It is shown that tensile hydrostatic pressure due to the unloading of the plastic waves at the free boundary and extensive shear-strain accumulation occurs at certain triple junctions. Furthermore, plastic shear-slip accumulation between inclusions and the surrounding martensitic matrix results in shear-strain localization and increases in the tensile hydrostatic pressure at critical locations, such as trip junctions.