The principle objectives of this study were to investigate deposition around test objects of a more complex geometry than bodies of revolution, using ultrasound, whilst over coming some of the problems previously encountered with ultrasonic imaging. Development of a new deaeration system reduced the number of bubbles (which attenuate ultrasound) in the milk flow to a satisfactory level, subsequently improving the quality of the ultrasound images. Further changes included the selection of a new rennet due to the unavailability of the original rennet used in the milk studies. Several rennets were investigated basing the final selection upon the similarity in behaviour, of the new and the original rennets, in response to agitation. A new test chamber was designed which allowed ultrasonic observation of the progressive development of clot structures and rate of deposition around various test objects, namely monoleaflet mechanical heart valves and monoleaflet valve models, during steady flow. Deposition resulting from pulsatile flow was too thin to be detected by ultrasound. It was seen from ultrasonic and visual observation that deposition thickness in regions of highest shear was thinner than in lower shear regions. Several mechanisms of deposition structure development were observed ultrasonically during steady flow, including a previously unreported mechanism.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:649045 |
| Date | January 2001 |
| Creators | Curtis, Corinna Briony Anne |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/13535 |
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