according to the iranian code of practice for seismic resistant design of buildings, soft storey phenomenon happens in a storey when the lateral stiffness of the storey is lower than 70% of the stiffness of the upper storey, or if it is lower than 80% of the average stiffness of the three upper stories. in the combined structural systems containing moment frames and shear walls, it is possible ...

the unsteady free convection flow between two long vertical parallel plates withvariable temperature and mass diffusion in the presence of the thermal radiation hasbeen presented. the governing dimensionless coupled linear partial differentialequations on the flow are solved by using the laplace transform technique. theexact solutions have been obtained for the fluid velocity, temperature and t...

nowadays, soil reinforcement using polymer elements have been investigated by a number of researchers in order to increase the load capacity of soils. reinforcing soils using fibers is a method of soil improvement, which offers a homogenous mixture in combination with soils, regarding their tensile strength. this combination maintains pressure loading capacity and properties in mutual resistant...

in the traditional hole drilling method the in-plane stresses are studied in detail and the interlaminar stresses are not taken seriously. the interlaminar stresses on the free edge of composite materials are important and can cause matrix cracking and delamination. inserting holes in composite laminates causes free edges and it can induce interlaminar shear and normal stresses. in this researc...

A flow apparatus has been developed for the study of the metabolic response of anchorage-dependent cells to a wide range of steady and pulsatile shear stresses under well-controlled conditions. Human umbilical vein endothelial cell monolayers were subjected to steady shear stresses of up to 24 dynes/cm(2), and the production of prostacyclin was determined. The onset of flow led to a burst in pr...

A method for improving adhesion between polymer films on Si substrates is described involving mechanical interlocking. Isotropic reactive ion etching (RIE) is applied to form pits in the Si substrate which fill upon application of a polymer via spinning. After curing, interpenetrating polymer lobes form a robust bond with the Si substrate. Adhesion improvements over films on smooth substrates a...

BACKGROUND This study describes a new method for determining site-specific vascular shear stress using dynamic measures of shear rate and blood viscosity (BV) in the carotid arteries, and examines characteristics of carotid arterial shear stress among patients with lacunar infarction. METHODS Vascular shear stress measurements were conducted in 37 patients (17 lacunar infarction patients and ...

Damage to red blood cells can be induced chemically, by osmosis or mechanically. The fluid mechanical effect can be related to the device design, its surface characteristics and to the degree of flow disturbance or turbulence caused by the device. Is generally accepted that the presence of high turbulent shear stresses generated in the flow fields of artificial devices are partially responsible...

a plain strain analysis of frictional rolling contact on an elastic graded coating is presented in this paper. finite element method is applied to gain an understanding of the stresses and contact zone properties caused during rolling contact. the effects of friction, material stiffness ratio and coating thickness on stresses in contact zone and coating/substrate interface are studied. shear mo...

We present experiments involving cancer cells adhering in microchannels, subjected to increasing shear stresses (0.1Pa to 30Pa). Morphological studies are carried out at different shear stresses. Cells exhibit spreading patterns similar to the ones observed in static conditions, as long as the shear stress is not too high. At critical wall shear stresses (around 2− 5Pa), cells decrease their ce...