background and objectives: kefiran (kef) is a water-soluble polysaccharide that can form transparent film however, it is brittle. therefore, in order to improve the mechanical properties of kefiran film, a mixture with other polymers can be offered. the expansion of mixed systems can propose kefiran and polyvinyl alcohol (pvoh) as a new composite film. materials and methods: solutions of 20 gra...

A hallmark of tissue ageing is the irreversible oxidative modification of its proteins. We show that single proteins, kept unfolded and extended by a mechanical force, undergo accelerated ageing in times scales of minutes to days. A protein forced to be continuously unfolded completely loses its ability to contract by folding, becoming a labile polymer. Ageing rates vary among different protein...

In any metal forming process, both the strain rate and deformation rate depend on the die profile. The die profile also, is responsible for the non-uniformity of the deformation along the cross-section. These affect the quality and mechanical properties of the product. Therefore, if a die is designed, in which the affecting variables can be controlled spontaneously it is hoped to obtain a produ...

Recently, bulk nano-structured materials produced by severe plastic deformation (SPD) have attracted scientists attention.  Materials produced by SPD are of great importance because of (1) non-porous structure, (2) great mechanical properties such as high strength and toughness and (3) proper dimension for mechanical and physical testing.  Several methods have been introduced for imposing the s...

Under mechanical loading, most living cells show a viscoelastic deformation that follows a power law in time. After removal of the mechanical load, the cell shape recovers only incompletely to its original undeformed configuration. Here, we show that incomplete shape recovery is due to an additive plastic deformation that displays the same power-law dynamics as the fully reversible viscoelastic...

fabrication of ultrafine grained materials by imposing severe plastic deformation for improvement of mechanical and physical properties of metals has been the focus of many researches over the past few years. in this process, a sheet is subjected to repetitive shear deformation conditions by utilizing asymmetrically grooved and flat dies through alternate pressing. in this study, a 2mm thick co...

in this work, dynamic mechanical properties of three high-manganese steels with trip/twip or fully twip characteristics are studied. high strain rate experiments in the range of true strain rates between ~500 and 1800 /s are conducted using a dynamic torsional testing setup. all the three steels show a positive strain rate sensitivity in the intermediate range of strain rates (up to 500 /s). bu...

external and internal changes in fruits during storage time are affected by the various factors that some of them can by studied by measuring the qualitative parameters (physical and mechanical). the effects of storage time on some physical and mechanical properties of valencia orange were investigated. the experiment was performed as factorial based on completely randomized design. analysis of...

Vertically aligned carbon nanotube (VACNT) arrays or “forests” represent a promising class of mechanically strong and resilient lightweight materials, capable of supporting large reversible deformation and absorbing mechanical energy. The mechanical response of VACNT forests to uniaxial compression is defined by various factors, including the material microstructure, its density, height, rate o...