left atrial (la) distension has been demonstrated to be linked with aortic stiffness in different patient populations. three-dimensional (3d) speckle-tracking echocardiography (ste) seems to be a promising tool for volumetric and functional evaluation of the la. the aim of the present study was to determine whether correlations exist between 3dste-derived la volume-based and strain parameter...

We find bounds on the effective elastic moduli of cracked materials in terms of the effective conductivity of such media. These represent the first non-trivial bounds on the effective properties of cracked media which are independent of the shapes and spatial distribution of the cracks. Different approximations for the elastic moduli of cracked media are tested against our bounds. The microgeom...

We investigate the properties of the QCD string in the Euclidean SU(N) pure gauge theory when the space-time dimensions transverse to it are periodic. We propose a generalisation of the Lüscher-Weisz effective string action for the flux-tube energy levels at finite L⊥. As the size of one transverse dimension is varied, we predict a Kosterlitz-Thouless transition of the worldsheet field theory a...

The purpose of the present work is to analyze the modulus of elasticity of graphene (Gr) sheet-reinforced metal matrix nanocomposites (MMNCs) using a homogenized model based on the Mori-Tanaka micromechanics approach. The main focus is to investigate the effects of Gr sheet agglomeration on the MMNC macroscopic elastic modulus. Also, the role of aligning Gr sheets in the mechanical performance ...

Many brittle materials, such as concrete, piezoelectricity, have a large number of preexisting microcracks, The determination of their effective material properties has been the focus of considerable research. Current research into the development of effective material properties has mostly concentrated on the Taylor's method[l], the self-consistent method[2], the differential theory[3], the Mo...

The impact of annular cracks on the effective elastic and conductive properties of a material is analysed. The compliance contribution tensor of an annular crack - the quantity that determines the increase in compliance of a solid due to introduction of such a crack - is derived analytically. The resistivity contribution tensor of an annular crack is calculated numerically. It is shown that an ...

We studied the elastic properties of bone to analyze its mechanical behavior. The basic principles of ultrasonic methods are now well established for varying isotropic media, particularly in the field of biomedical engineering. However, little progress has been made in its application to anisotropic materials. This is largely due to the complex nature of wave propagation in these media. In the ...

nanocomposites made of carbon nanotube (cnt) bundles have attracted researchers’ attention due to their unusual properties such as: light weight, flexibility and stiffness.  in this paper, the effects of straight and rope-shaped bundles on nanocomposite effective mechanical properties are investigated.  first, fea models are created consisting of cnts with different shapes of straight and rope-...

in the current paper, finite element method is employed for numerical simulations and the study of influential parameters on elastic modulus of polymer-matrix nano-composites. effects of different key parameters including particle elastic modulus, interphase elastic modulus, matrix elastic modulus, interphase thickness and particle volume fraction on total elastic modulus of nano-composite mate...

We consider elastic wave velocities in fluid-saturated porous media with pore fluids distributed in “patches” (i.e., heterogeneity much larger than the typical pore size). We model elastic properties of such materials using inclusion-based effective medium theory (IBEMT). The standard IBEMT formulation assumes insufficient time during the wave cycle for pore fluids to flow in response to wave-i...