THE EFFECTS OF BLOOD REHEOLOGICAL ON THE FLOW THROUGH AN AXISYMMETRIC ARTERIAL STENOSIS

The prediction of the blood flow through an axisymmetric arterial stenosis is one of the most important aspects to be considered during the Atherosclrosis. Since the blood is specified as a non-Newtonian flow, therefore the effect of fluid types and effect of rheological properties of non-Newtonian fluid on the degree of stenosis have been studied. The motion equations are written in vorticity-stream function formulation and solved numerically. A comparison is made between a Newtonian and non-Newtonian fluid for blood flow at different velocities, viscosity and Reynolds number were solved also. It is found that the properties of blood must be at a certain range to preventing atheroscirasi

Theoretical Prediction of Cavitation in Radial Inflow Turbines at Design and off-Design Conditions

A theoretical method for the prediction of cavitation in hydraulic radial turbines is developed in this work. The method combines a steady, quasi-three dimensional analyses which are based on the streamline curvature technique with an approach for the prediction of cavitation based on the definition of "available" and "required" cavitation coefficients. A radial inflow turbine is selected as a test case to investigate the capability of the present method as a cavitation prediction tool at design and offdesign conditions. The effects of various operating conditions on the cavitation inception are examined at constant values of total head and turbine suction head. It has been found that cavitation is formed near the outlet when the turbine operated at the design speed. While at off-design speeds and flow rates, cavitation covers longer distances along suction and pressure surfaces

Experimental Investigation of a Temperature Change inside Pneumatic Cylinder Chambers

The investigation of the existence of a tempera-ture change with pressure inside the pneumatic cylinder chambers during the charging and dis-charging strokes in the pneumatic cylinder is ex-perimentally demonstrated. Three different varia-bles (pressure, piston displacement and tempera-ture) were measured in this work while operating with a servo pneumatic system and a discussion of the relationship between these variables was pre-sented. The cylinder used has a piston diameter of (0.05m), piston rod diameter (0.02m) and a stroke length of (0.2m). The results show a temperature rise of 23 K above atmospheric temperature at chamber (1) while air compressing and a tempera-ture drop of 17 K below atmospheric temperature at chamber (2) while air expansion and measures other temperature changes also

Successful management of severe refractory acquired immune bleeding disorder: Prior to insisting surgery

AbstractINTRODUCTIONAcquired bleeding disorders are rare and may be missed before surgery. Additionally, they may be refractory to conventional treatments.PRESENTATION OF CASEA 50-year-old patient experienced prolonged post-operative bleeding when his bleeding disorder was missed prior to his undergoing inguinal herniorrhaphy. Post-operative investigations revealed severe acquired von Willebrand syndrome associated with a monoclonal gammopathy of undetermined significance. A few months later, he required umbilical herniorrhaphy, but he did not respond to attempts to raise his von Willebrand factor antigen and activity levels using conventional therapies, including desmopressin, cryoprecipitate, intravenous immunoglobulin, and Von Willebrand factor concentrate. A triple therapy combination of dexamethasone, intravenous immunoglobulin, and mycophenolate mofetil was administered, with a successful and sustained response, lasting about 2 months. The surgery was performed safely, without any complications.DISCUSSIONConventional acquired von Willebrand syndrome treatment is usually aimed at replacing von Willebrand factor or stimulating its secretion from storage in endothelial cells. In the present case, the alternative treatment was directed against both the humoral and cell-mediated immune mechanisms.CONCLUSIONThis case of acquired bleeding disorder showed that more attention must be given to a patient's coagulation profile, even if only very minor laboratory coagulation derangements are detected prior to surgery, to avoid missing such rare disorders. The described triple therapy demonstrated good effects and may be considered for inclusion in a controlled randomized study to determine its usefulness for other surgeries delayed due to severe acquired bleeding disorders. To the best of our knowledge, this triple combination treatment has not been previously used for the treatment of severe acquired bleeding disorders that are refractory to conventional therapies

Effect of Surface Roughness Height on the Aerodynamics Performance of Axial Compressor Cascade Blades

The performance of fluid handling mechanical parts such as compressor blades are usually significantly affected by the surface roughness, because they often operate in condition of peak output that is close to this flow condition. The influence of surface height roughness of compressor blades has been investigated experimentally under the effect of cascade stagger angle. The experimental results done by using the direct measuring technique showed that the aerodynamic coefficients of compressor cascade blades influences by presences of surface roughness and stagger angle. The lift coefficient, pitching moment coefficient and cascade blade efficiency were reduced, while the drag coefficient is increased, with the increase of height roughness. The height of roughness does eliminate the operating condition of the cascade blades, which reduce the value of the stall angle

INVESTIGATION AND MODIFICATION OF AERODYNAMIC CHARACTERISTICS OF SUPERSONIC AIRCRAFT

Increasing the aerodynamic efficiency and enhancing the supermaneuverability for the selected supersonic aircraft (F-16A) is presented. Aerodynamic characteristics, surface pressure distribution and maximum lift are are estimated for the baseline configuration for different Mach number and angles of attack in subsonic and supersonic potential flow, using a low order three- dimensional panel method supported with semi-empirical formulas of Datcom. Estimation of the total nose-up and nose-down pitching moments about the center of gravity of the completed aircraft in subsonic region depending on the flight conditions and aircraft performance limitations. A modern program was implemented by suggesting a two dimensional thrust vectoring technique (pitch vectoring up and down) controlled by the best design of advanced aerodynamic and control surface (foreplane or canard). Work results shows that the canard (as a control surface) with thrust vectoring produces enough nose-down moment and can support the stabilator at high maneuvers, while for an aerodynamic surface, a rate of (5-6%) increase was achieved in the aerodynamic efficiency (lift-to-drag ratio) of the baseline configuration in both subsonic and supersonic fligh

Study of Three Dimensional Fluid Flow inManifold-Laterals System

A three dimensional numerical simulation of fluid flow in a manifold-laterals system was carried out; several geometrical changes were made to study the effect on water flowing inside the manifold. The manifold hydraulic diameter and the length were kept constant in the study. The geometrical changes include the distance between laterals, the length of the laterals, and the laterals size. It is found that for Reynolds Number (100 and 1000), increasing the length of the laterals gives uniform flow profile at laterals outlet. Also reducing lateral size will create a similar effect. A good agreement was found between the present and FLUENT6.2 results for mass flow rate from laterals

Optimum socio-environmental flows approach for reservoir operation strategy using many-objectives evolutionary optimization algorithm

Water resource system complexity, high-dimension modelling difficulty and computational efficiency challenges often limit decision makers' strategies to combine environmental flow objectives (e.g. water quality, ecosystem) with social flow objectives (e.g. hydropower, water supply and agriculture). Hence, a novel Optimum Social-Environmental Flows (OSEF) with Auto-Adaptive Constraints (AAC) approach introduced as a river basin management decision support tool. The OSEF-AAC approach integrates Socio-Environmental (SE) objectives with convergence booster support to soften any computational challenges. Nine SE objectives and 396 decision variables modelled for Iraq's Diyala river basin. The approach's effectiveness evaluated using two non-environmental models and two inflows' scenarios. The advantage of OSEF-AAC approved, and other decision support alternatives highlighted that could enhance river basin SE sectors' revenues, as river basin economic benefits will improve as well. However, advanced land use and water exploitation policy would need adoption to secure the basin's SE sectors

An Alternative Model to Overcoming Two Phase Commit Blocking Problem

In distributed transactions, the atomicity requirement of the atomic commitment protocol should be preserved. The two phased commit protocol algorithm is widely used to ensure that transactions in distributed environment are atomic. However, a main drawback was attributed to the algorithm, which is a blocking problem. The system will get in stuck when participating sites or the coordinator itself crashes. To address this problem a number of algorithms related to 2PC protocol were proposed such as back up coordinator and a technique whereby the algorithm passes through 3PC during failure. However, both algorithms face limitations such as multiple site and backup coordinator failures. Therefore, we proposed an alternative model to overcoming the blocking problem in combined form. The algorithm was simulated using Britonix transaction manager (BTM) using Eclipse IDE and MYSQL. In this paper, we assessed the performance of the alternative model and found that this algorithm handled site and coordinator failures in distributed transactions using hybridization (combination of two algorithms) with minimal communication messages