We describe the use of a continuous-flow clinical analyzer with an immobilized coupled-enzyme nylon tube reactor and an immobilized single-enzyme nylon tube reactor for routine estimation of lactate and pyruvate in serum. These reactors are incorporated into the flow system of a modified continuous-flow analyzer (Technicon AutoAnalyzer). Results for serum lactate and pyruvate by this method are...

Application of transition flow can be found in several processes and systems. It has been revealed through findings from various researchers that the values Reynolds numbers at which occurs vary. In current work, investigations were numerically conducted by Fluent on water three assorted plain tubes fitted with miscellaneous tape insertions. They are tube crossed-axes-circle-cut insert (C-C tub...

An oxidation process is simulated for a bundle of metal tubes in a cross–flow. A fluid flow is governed by the incompressible Navier–Stokes equations. To describe the transport of oxygen, the corresponding convection–diffusion equation is applied. The key point of the model is related to the description of oxidation processes taking into account the growth of a thin oxide film in the quasi–stat...

OBJECTIVES AND METHODS Impaired blood flow of the upper end of the gastric tube is one of the major causes of anastomotic leak following esophageal reconstruction after esophagectomy for cancer. We applied an additional microvascular anastomosis procedure--the supercharging technique--to improve blood flow. We investigated blood flow improvement in 15 patients who underwent the supercharging te...

In designing of condensers, the prediction of pressure drop is as important as the prediction of heat transfer coefficient. Modeling of two phase flow, particularly liquid – vapor flow under diabatic conditions inside a horizontal tube using CFD analysis is difficult with the available two phase models in FLUENT due to continuously changing flow patterns. In the present analysis, CFD analysis o...

Numerical simulations of unsteady flow in a Hartmann resonance tube are carried out with the goal of understanding the effect of jet Mach number on the flow characteristics. The device, which consists of a convergent nozzle facing a closed end tube produces a nearly normal shock that fluctuates in the gap between the nozzle and the tube. Numerical solutions were obtained for the unsteady Reynol...

A straight tube with a smooth axisymmetric constriction is an idealised representation of a stenosed artery. We examine the three-dimensional instability of steady flow plus an oscillatory component in a tube with a smooth 75% stenosis using both linear stability analysis and direct numerical simulation. These flows become unstable through a subcritical period-doubling bifurcation involving alt...

mathematical model is developed for the time-dependent circular tube flow of compressible olymeric liquids subject to pressure-dependent slip at the wall and applied to a poly dimethyl iloxane PDMS . The parameters of pressure-dependent wall slip velocity and shear viscosity of he PDMS were determined using combinations of small-amplitude oscillatory shear, steady orsional and squeeze flows and...

BACKGROUND In vivo studies have shown that valves in veins are paired in an orthogonal configuration. The aim of this study is to characterize the flow interaction of paired valves under controlled in vitro bench conditions. METHODS A bench top in vitro experiment was set up at physiological flow conditions to simulate the flow inside a venous valve. Two bicuspid bioprosthetic valves paired i...

The paper presents the analysis of the energy performance of an air vortex cooling tube under variations of the air inlet properties, with three independent experimental tests validated through the energy balance in the device. The experimental analysis includes the following variations of the input conditions: First, the effect of the air inlet pressure to the vortex tube, focused on the analy...