In this article, we examine the elastic properties of boron-nitride nanotubes, which are embedded in amorphous silicon-boron-nitride ceramics. We employ molecular dynamics simulations using the Parrinello-Rahman approach. To this end, all systems are modeled with a reactive many-body bond order potential due to Tersoff, which is able to describe covalent bonding accurately. We apply external st...

BACKGROUND Decreased arterial elasticity is a risk factor for several cardiovascular outcomes. Longitudinal data on the effect of physical activity in youth on adult arterial elasticity are limited. The aim of this study was to determine the long-term effects of physical activity in children and young adults on carotid artery elasticity after 21 years of follow-up. METHODS AND RESULTS Partici...

in this work we use density functional theory based on the ultra-soft pseudo-potential to calculate thestructural, mechanical and thermal properties of narrow single walled bn, aln and gan nanotubes.the electron-electron interactions were expressed within the local density approximation (lda). wehave also obtained the phonon dispersion and elastic constants of these nanotubes using the densityf...

We obtain a formula for the modulus of metric regularity of a mapping defined by a semi-infinite system of equalities and inequalities. Based on this formula, we prove a theorem of Eckart-Young type for such set-valued infinite-dimensional mappings: given a metrically regular mapping F of this kind, the infimum of the norm of a linear function g such that F + g is not metrically regular is equa...

The water flow through the poly(acrylamide) gel under a constant water pressure is measured by newly designed apparatus. The Young modulus and Poisson's ratio of the rod shape gels are measured by the uni-axial elongation experiments, which determine the longitudinal modulus independently from the water flow experiments. The time evolution of the water flow in the dilute gel is calculated based...

Elasticity measurements of bilayer lipid membranes (BLM) based on registration of the third harmonic of the membrane current during the application of a periodic tension to the membrane was used to study the effects of lipid peroxidation (LPO) and phospholipase A on BLM. LPO resulted in decreased values of the Young modulus for BLM, while some products of LPO and phospholipid hydrolysis (linole...

Lattice constant, density, total energy, cohesive energy, bulk modulus, microhardness, Young modulus, speed of sound, energy of acoustic phonons, plasmon energy and vibrational energy, for diamond, silicon, germanium, and gray tin, all have been calculated and studied when compression stress is exerted. It is found that most of them increase with pressure except the lattice constant which decre...

Recent experiments have demonstrated that electron irradiation of bundles of single-walled carbon nanotubes resulted in dramatic increase of the bundle bending modulus at moderate irradiation doses, followed by a decrease in mechanical properties at higher doses. To understand such a behavior, we employ molecular dynamics simulations with empirical potentials and analytical approximations to ca...

Polymer blends composites were prepared according to the formula [84%LLDPE:15%((100-X)%PP:X%PVP):1%B.P] with weight ratios selected for X values (0,4,8,12,16 %), as strips by double screw extruder and use press process the strips to prepare the samples according ASTM specification, the mechanical properties were studied for all theprepared samples which are (tensile, flexural, compression, impa...

Tendons primarily function as contractile force transmitters, but their mechanical properties may change dependent upon their level of mechanical usage. Using an ultrasound-based technique we have assessed tendon mechanical properties in vivo in a number of conditions representing different levels of mechanical usage. Ageing alters tendon mechanical properties; stiffness and modulus were lower ...