this paper presents a numerical study of local mass transfer coefficients in a 90° bend using the rng version of k–e model to include the influence of curvature on the turbulent transport. simulations were performed for flow through a 90°, 3-d bend for reynolds numbers of 13500, 90000, and 390000, schmidt numbers of 2.53 and 700 and curvature ratios of 1.5, 2, and 2.5. the differences between t...

previous studies have shown that electrical stimulation (es) increases blood flow, but the exact mechanisms are not clear. the present study was designed to clarify some of the underlying mechanisms involved in this phenomenon. white adult rabbits lt.-6 months old were used. animals were anesthetized by sodium pentobarbital (40 mg/kg, iv) and skin blood flow in the thoracic back was recorded us...

in this work, a bench-scale process was developed using mineral-processing methods to recover iron from a placer deposit located in bardaskan, khorasan-e-razavi, iran. the mineralogical studies were performed by x-ray diffraction (xrd), x-ray fluorescence (xrf), electron probe micro-analyzer (epma), and an optical microscope. these studies indicated that titanomagnetite, magnetite, and hematite...

background programmed cell death (apoptosis) is a physiological process needed to remove unwanted or damaged cells. it has been hypothesized that any failure of programmed cell death leads to the development of neoplasm. identifying new agents which induce apoptosis in tumor cells is of great significance in treatment of neo­plasms. numerous studies suggest that exposure of tumor cells to stati...

background sulfur oxides released from the burning of oil causes severe environmental pollution. the sulfur can be removed via the 4s pathway in biodesulfurization (bds). immobilization approaches have been developed to prevent cell contamination of oil during the bds process. objectives the encapsulation of rhodococcus erythropolis r1 in calcium alginate beads was studied in order to enhance c...

Flow separation at water intake is the main cause of head loss and flow discharge reduction. &#10As a result, study of shape and size of separation is very essential when designing an optimum water intake. Water intake is normally built with a 90 degree angle to the main channel flow direction. However, the flow structure in this type of water intake consists of large separation size along wit...

Flow visualization techniques using tracer markers such as die, smoke, hydrogen bubbles, etc., have been widely used in experimental investigations of large scale structures of a variety of flow fields. They have played an important role in understanding the physics of the coherent structures formation and evolution in the transitional as well as the turbulent regions of the flow fields. Howeve...

The single-phase flow and thermal performance of a double pipe heat exchanger are examined by experimental methods. The working fluid is water at atmospheric pressure. Temperature measurements at the inlet and outlet of the two streams and also at an intermediate point half way between the inlet and outlet is made, using copper-constantan thermocouple wires. Mass flow rates for each stream are ...

The objective of current paper is 3D simulation of turbulent, developing flow and unsteady within a circular duct in presence of the body force vector persuaded by Dielectric barrier discharge (DBD) plasma actuator inside the surface of geometry for the first time. This article aims at investigating of applying plasma actuator to control separation with special arrangement of electrodes. For th...

Flow separation at water intake is the main cause of head loss and flow discharge reduction. As a result, study of shape and size of separation is very essential when designing an optimum water intake. Water intake is normally built with a 90 degree angle to the main channel flow direction. However, the flow structure in this type of water intake consists of large separation size along with ...