oily wastewaters from oil refineries and oil distribution centers are one of the most important environmental concerns in recent decades; therefore, it is critical to treat these types of wastewaters. in this study, the performance of different polyethersulfone hollow fiber membranes in oily wastewaters treatment was investigated and the effects of operating conditions such as transmembrane pre...

conclusions results suggest that these methods cannot be interchanged, and vvi showed significantly lower lv peak twist, peak twisting rate and peak untwisting rate. however, when lv twist and lv twisting rates were normalized to lv length, values were comparable for both imaging techniques. results twist degree was significantly lower in the vvi group than in the tdi group (p = 0.008, r = 0.56...

in this paper the effects of non-linearity of suspension on dynamic behavior of a railway wheelset has been studied. this wheelset has four degrees of freedom that with two constraints it has reduced to two degrees of freedom. vermeulen-johnson theory has been used to calculate contact forces between wheel and rail. in this study the creep coefficients have considered constant. any linearizatio...

Soil detachment is known as an important process in soil erosion and its quantification is necessary to establish a basic understanding of erosion. This study was carried out to find the best flow erosivity indicator(s) for predicting detachment rate at low slopes. For this purpose, 12 experiments including 6 flow discharges (75, 100, 125, 150, 175 and 200 ml/s) and 2 slope gradients (1.5 and 2...

This paper investigates the parametric excitation of a micro-pipe conveying fluid suspended between two symmetric electrodes. Electrostatically actuated micro-pipes may become unstable when the exciting voltage is greater than the pull-in value. It is demonstrated that the parametric excitation of a micro-pipe by periodic (ac) voltages may have a stabilizing effect and permit an increase of the...

BACKGROUND Doppler-tipped coronary guide-wires (FW) are well-established tools in interventional cardiology to quantitatively analyze coronary blood flow. Doppler wires are used to measure the coronary flow velocity reserve (CFVR). The CFVR remains reduced in some patients despite anatomically successful coronary angioplasty. It was the aim of our study to test the influence of changes in flow ...

in the present work, the effect of fluid’s elasticity was investigated on the hydrodynamic instability of blasius flow. to determine the critical reynolds number as a function of the elasticity number, a two-dimensional linear temporal stability analysis was invoked. the viscoelastic fluid is assumed to obey the walters’ b fluid model for which base flow velocity profiles were fortunately avail...