Numerical research of double‐diffusive natural convection in elliptical cylinders: Effect of thermal Rayleigh number

This paper is the first part of a two‐part study, and it presented numerical research of double‐diffusive natural convection within an annulus area, situated in two horizontal confocal elliptic solids charged by a Newtonian fluid. The elliptical coordinates were used to transform the physical domain into a rectangular one. To resolve the governing equations and the boundary layer conditions, a calculator code based on the finite volume approach was developed. The details of the influences of thermal Rayleigh number on heat and mass transfer were investigated. Results obtained were compared with those existing in other reasearch works.     

Analysis of the Dynamic Behavior of Magnetorheological Elastomer Composite: Elaboration and Identification of Rheological Properties

Silicon - The present work is devoted to experimental analysis of the magnetorheological elastomer composite behavior under dynamic loading. The elastomer is charged to 40% of ferromagnetic...     

Forced transverse vibration of composite sandwich beam with magnetorheological elastomer core

We studied, experimentally and numerically, the vibrational response of a magnetorheological elastomer sandwich beam, clampedfree, delimited by two skins aluminum 7075T6, first subjected to a variable magnetic field perpendicular to the skin of the beam, and second to a harmonic excitation by magnetic force applied at the free end. Our main objective was to predict the effect of the intensity of the current flowing through a coil on several dynamic factors. The maximum amplitude of resonance and the variation of the loss factor as a function of structural stiffness are adjusted simultaneously by the application of different magnetic fields. The results of both methods are compared.     

First-Principle Investigations of Structural,Electronic, and Half-Metallic Ferromagnetic Properties in In1−xTM x P (TM = Cr,Mn)

First-principle calculations within the framework of density functional theory are employed to study the structural, electronic, and half-metallic ferromagnetic properties of In_1?x (TM) _x P (TM = Cr, Mn) at concentrations (x = 0.0625, 0.125, 0.25)of transition metal in zinc blende phase. The investigations of electronic and magnetic properties indicate that In_1?xTM _x P (TM = Cr, Mn) at x = 0.0625, 0.125, and 0.25 are half-metallic ferromagnets with 100 % magnetic spin polarization. On the one hand, the total magnetization is an integer Bohr magneton of 3 μ _B and 4 μ _B for In_1?xCr _x P and In_1?xMn _x P, respectively, which confirms the half-metallic feature of In_1?xTM _x P compounds. On the other hand, the densities of states of majority-spin states show that the large hybridization between 3p (P) and 3d (TM) partially filled states dominates the gap, which stabilizes the ferromagnetic state configuration associated with double-exchange mechanism. The band structures depict that half-metallic gap at x = 0.0625 is 0.404 eV for In_1?xCr _x P which is higher than 0.125 eV for In_1?xMn _x P. Therefore, the largest half-metallic gap in In_1?xCr _x P at low concentration x = 0.0625 reveals that Cr-doped InP seem to be a more potential candidate than that Mn-doped InP for spin injection applications in the field of spintronic devices.     

First-Principles Investigation of Half-metallic Ferromagnetism in V-doped BeS, BeSe, and BeTe

We have investigated the electronic structure and half-metallic ferromagnetism in zinc blende phase of Be_1?x V _x M (M=S, Se, Te) at concentration x=0.125 by employing a first-principles calculations within the framework of density functional theory (DFT) based on the linearized augmented plane wave method (FP-LAPW), as implanted in the WIEN2k code with generalized gradient approximation functional proposed by Wu and Cohen (WC-GGA). The electronic properties exhibit half-metallic behavior. So the density of states shows the hybridization between the p (S, Se, Te) and 3d (V) states that creates the antibonding states in the gap, which stabilizes the ferromagnetic ground state associated with the double-exchange mechanism, whereas the spin polarized band structures depict half-metallic gap that increases from Be_0.875V_0.125S to Be_0.875V_0.125Se to Be_0.875V_0.125Te. These compounds are robust half-metallic ferromagnets with spin polarization of 100 % and predicted to be potential candidates for spin injection applications in spintronic devices. Therefore, our predictions require an experimental confirmation in the future.     

Large Eddy Simulation of a Turbulent Flow in a Differentially Heated Cavity with Rayleigh Numbers up to 1011： Part I,Numerical Methods

Large Eddy Simulations of the anisothermal turbulent flows has been used in the context of interaction problems thermal fluid, structure. In this context, the aim of this work lies not only in identifying the various elements that may underestimate the temperature fluctuations at the interface fluid-solid but also the introduction of the models capable of reproducing the physical setting Thurs. At first, the choice of convection scheme 〈optimizing〉 the scalar transport has led to the adoption of an upwind scheme of theorem 2 order. The use of models with conventional walls showed weaknesses in the estimation of temperature fluctuations bet stalls in the case of boundary layers attached. This work presents a numerical validation of LES-WALE model using the results of the K-epsilon model, this study is based on 3D numerical simulation using FLUENT code calculates to determine the longitudinal velocity, the thermal fields for the configuration the and speed vectors （U, V, W） for configuration in the plane of the recirculation zones for the case of different values of flow Rayleigh. Therefore, the results have good agreement with those of k-epsilon model, as they show the difference between the cases of flows.     

First-principles investigations of structural, elastic, electronic and magnetic properties of Ga1−x Mn x P and In1−x Mn x P

We employ the full-potential linearized augmented plane wave plus local orbital (FP L/APW + lo) method based on the density functional theory (DFT) in order to investigate the structural, elastic, electronic, and magnetic properties of ordered dilute ferromagnetic semiconductors Ga_1?x Mn _x P and In_1?x Mn _x P at (x = 0.25) in the zinc blende phase, using generalized gradient approximation, GGA (PBE). To our knowledge the elastic constants of these compounds have not yet been measured or calculated, hence our results serve as a first quantitative theoretical prediction for future study. Results of calculated electronic structures and magnetic properties reveal that both Ga_0.75Mn_0.25P and In_0.75Mn_0.25P have stable ferromagnetic ground state, and they are ideal half-metallic (HM) ferromagnetic at their equilibrium lattice constants. Also we show the nature of the bonding from the charge spin-densities calculations. The calculated total magnetic moments are 4.0 μ_B per unit cell for both Ga_0.75Mn_0.25P and In_0.75Mn_0.25P, which agree with the Slater–Pauling rule quite well, and we observe that p–d hybridization reduces the local magnetic moment of Mn from its free space charge value and produces smaller local magnetic moments on the nonmagnetic Ga, In and P sites. The values of N ₀α and N ₀β exchange constants confirm the magnetic nature of these compounds. From the robust half-metallicity of Ga_0.75Mn_0.25P and In_0.75Mn_0.25P as a function of lattice constant is also investigated.