A numerical analysis of hemodynamics for arterial medical procedures

The present research consisted of two investigations using computational fluid dynamics (CFD) to simulate the hemodynamics of arterial systems. In the first investigation, numerical simulations of flow in an intracranial side-wall aneurysm were performed. The resulting velocity vectors and vorticity contours compared very favorably with data from microPIV experiments on an equivalently-sized aneurysm geometry. However, there was evidence to suggest that the elastic walls in the microPIV experiments (which were not modeled in the numerical simulations) played a role in sustaining primary vortex development within the aneurysm, particularly during pulse phases of high velocity. Successful reproduction of the experimental velocity field allowed the simulations to be used to quantify other important variables, such as wall shear and pressure, within the aneurysm. A region of high wall shear stress oscillation and large pressure gradients were found near the distal aneurysm neck. In the second investigation, stent reconstruction of an aorta-iliac bifurcation was simulated using CFD. The effects of stent presence, alignment, and permeability were investigated. Stent presence lowered wall shear stress along stented artery walls and elevated streamwise vorticity near the stent inlets and outlets. When reconstruction featured two mis-aligned stents, wall shear stress decreased and streamwise vorticity increased, proportional to the degree of mis-alignment. Low permeability stents magnified the flow abnormalities seen in the stent presence simulations. The modeling technique, representing stents by a porous jump boundary condition, is novel and its results agree well with the cited literature on experimental and numerical stent research

The Travel Act : A New Statutory Approach to Organized Crime in the United States

The role that the Federal Government should play in the control of crime in a federal system continues to be one of the most perplexing problems confronting all persons concerned with the administration of justice in this country. Under our system of government, it is both essential and desirable that the detection of crime and prosecution of criminals be primarily state and local functions. But an increasing crime rate, documented over the years by the statistical reports of the Federal Bureau of Investigation, has suggested that local authorities need help from the Federal Government in the performance of their law enforcement responsibilities

Analyzing Photo-Electric Smoke Detector Response Based On Aspirated Smoke Detector Obscuration

Accurate obscuration levels at the response time of photo-electric smoke detectors are needed for proper detection modeling and analysis. In recent works, obscuration meters were used to measure the obscuration level at photo-electric detector response. In this study, aspirated smoke detectors (VESDA) were used to measure this same obscuration level. These detailed measurements were used to reduce the ambient light and the technology difference error associated with the obscuration meters. The use of aspirated smoke detection (VESDA) instead of light obscuration meters displayed increased accuracy for a majority of the experiments conducted in the 2008 report titled "Validation of a Smoke Detection Performance Prediction Methodology" involving flaming and non-flaming incipient fire sources at 3 different ventilation conditions