In this paper we present ab initio many-body calculations on the strain energy of W silica, taken as a model system for edge-sharing tetrahedral SiO(2) systems with respect to corner-sharing ones as in alpha quartz. The mean-field results were obtained using the restricted Hartree-Fock approach, while the many-body effects were taken into account by the second-order Møller-Plesset perturbation ...

  Background: The main purpose of this study was to determine the relationship between serum vitamin D and the status of bone mineral density in patients with low-energy hip and distal radius fracture. Methods: This retrospective case-control study was performed between January 2013 and January 2014. Participants aged 55 years or older were divided to case group including 85 patients with lo...

Strain-dependent structural and electronic properties of MoS2 materials are investigated using first principles calculations. The structural and electronic band structures of the MoS2 with relaxed unit cells are optimized and calculated by the dispersion-corrected density functional theory (DFT-D2). Calculations within the local density approximation (LDA) and GGA using PAW potentials were also...

in this article, zno and zno:mn nanoparticles prepared by reverse micelle method. the various crystalline properties of these nanoparticles such as size, d-spacing, strain, stress, dislocation density and texture coefficient have been calculated with the help of xrd spectrum. the xrd results indicated that the synthesized zno and zno:mn nanoparticles have a pure wurtzite (hexagonal phase) struc...

Ti-6Al-4V bridges were additively fabricated by selective laser melting (SLM) under different scanning speed conditions, to compare the effect of process energy density on the residual stress state. Subsurface lattice strain characterization was conducted by means of synchrotron diffraction in energy dispersive mode. High tensile strain gradients were found at the frontal surface for samples in...

Accumulative roll bonding (ARB) imposes severe plastic strain on materials without changing the specimen dimensions. ARB process is mostly appropriate for practical applications because it can be performed readily by the conventional rolling process. An Al-2wt%Cu alloy was subjected to ARB process up to a strain of 4.8. Stacking of materials and conventional roll-bonding are repeated in the pro...

The applicability of several fatigue damage models for polyether ether ketone (PEEK) under mean strain and variable amplitude multi-block loadings is evaluated. The models utilized in this study are assessed against experimental data for PEEK under various cyclic loading conditions, including (1) constant amplitude loading with non-zero mean strains, (2) two-block loading with zero and non-zero...

Nomenclature A Aperture area of the antenna (square meters) D Diameter of antenna aperture (meters) Ef Gravitational potential energy due to film (Joules) Ep Hydrostatic pressure potential energy (Joules) ET Total energy of the inflatable reflector system (Joules) F Focal length of antenna (meters) G Effective antenna gain GI Ideal antenna gain g Acceleration due to gravity (meters per square s...

The problem of several finite moving cracks in a functionally graded material is solved by dislocation technique under the condition of anti-plane deformation. By using the Fourier transform the stress fields are obtained for a functionally graded strip containing a screw dislocation. The stress components reveal the familiar Cauchy singularity at the location of dislocation. The solution is em...