Mechanical & Materials Engineering, Department of


Date of this Version

Spring 4-11-2011


A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of the Requirements For the Degree of Master of Science, Major: Mechanical Engineering, Under the Supervision of Professor Linxia Gu. Lincoln, Nebraska: May, 2011

Copyright 2011 Eric L. Cutler


Gas emboli are a clinical issue often encountered in the space exploration, marine construction, and medical fields. Individuals involved with these disciplines will often have asympomatic gas emboli circulating throughout their bodies on a regular basis. A study into the impact of chronic asymptomatic gas emboli on the risk of atherosclerosis in humans is thus presented. This research utilized a custom built cardiovascular flow simulator and accompanying data acquisition system to experimentally determine the influence of gas emboli under varied circumstances on the mean wall shear stress of a tube in-vitro. A directly inverse relationship between gas embolus presence in the blood stream and mean wall shear stress, particularly at low vascular flow and pulse rates was subsequently found. While the study was unable to support or refute any significant effect of gas emboli on the onset of atherosclerosis it did establish a positive causal link between bubbles in the bloodstream and diminished mean wall shear stress.