A flow injection system for the determination of selenium by electrochemical hydride generation and quartz tube atomic absorption spectrometry is described. The generator consists of an electrolytic flow-through cell with a concentric arrangement and a packed cathode made of particulated lead. The influences of sample flow rate, carrier gas flow rate and electrolysis current on the hydrogen sel...

In pipeline-riser systems, pressure fluctuations which result from the formation of large liquid slugs and gas surges due to operational changes or low mass flow rate from production wells and the profile of pipeline-riser systems often lead to trips at the inlet of the separator; and thereby, the problem causes a a loss of the production.In this study, on a sample deep-water oil field off the ...

variability of tidal volume and respiratory rate in normally breathing man has long been demonstrated [1]. however because of lack of knowledge and technology primary ventilators could only deliver a fixed tidal volume in a fixed rate the so called volume controlled ventilation (vcv). vcv was volume preset time triggered and cycled and there was no synchronization with patient’s breaths. at tha...

Symptom-limited supine bicycle exercise with radionuclide angiography was performed on 11 patients with severe mitral regurgitation (who were not receiving vasodilators), to assess changes in left ventricular volume, regurgitant fraction, forward flow and regurgitant flow during exercise. All patients were in normal sinus rhythm with a normal resting ejection fraction (greater than 0.50). Durin...

We describe a standard set of quantity names and symbols related to the estimation of kinetic parameters from dynamic contrast-enhanced T(1)-weighted magnetic resonance imaging data, using diffusable agents such as gadopentetate dimeglumine (Gd-DTPA). These include a) the volume transfer constant K(trans) (min(-1)); b) the volume of extravascular extracellular space (EES) per unit volume of tis...

This article considers transient flows for planar contractions and Oldroyd-B fluids, with increasing flow-rate boundary conditions. We employ a novel hybrid finite volume/element time-dependent algorithm. The hybrid scheme consists of a TaylorGalerkin finite element discretisation, and a cell-vertex fluctuation-distribution finite volume approach. These two approaches are coupled at each time-s...

changes of hydrodynamic parameters in microchannel branches affect the suspended biological samples in blood. to prevent denaturation and hemolysis, we have numerically investigated the effect of divergence angle on shear rate and velocity at branch entrance (discharge rate), under electroosmotic flow. in such flow, hydrodynamic properties are also affected by zeta potential at the microchannel...

Processes utilizing various spraying cooling are widely used in many gas treatment applications. Effective spray cooling system design optimization often depends on the approach used to investigate such gas cooling problems. The mass transfer efficiency of spray cooling problems depends on the ability of the liquid to atomize and disperse into the gas by interacting in a controlled manner. Expe...

The velocity profile and pressure gradient of an unsteady state unidirectional MHD flow of Voigt fluids moving between two parallel surfaces under magnetic field effects are solved by the Laplace transform method. The flow motion between parallel surfaces is induced by a prescribed inlet volume flow rate that varies with time. Four cases of different inlet volume flow rates are considered in th...