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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal align=center style='text-align:center'><b><span style='font-size:18.0pt;line-height:115%'>UNIVERSITY OF HOUSTON<o:p></o:p></span></b></p><p class=MsoNormal align=center style='text-align:center;line-height:normal'><b><span style='font-size:12.0pt'>Cullen College of Engineering </span></b><span style='font-size:12.0pt'>4800 Calhoun Rd.<o:p></o:p></span></p><p class=MsoNormal align=center style='text-align:center;line-height:normal'><span style='font-size:12.0pt'>Department of Mechanical Engineering Houston, TX 77024-4005<o:p></o:p></span></p><p class=MsoNormal align=center style='text-align:center'><span style='font-size:14.0pt;line-height:115%'>Thesis Defense<o:p></o:p></span></p><p class=MsoNormal style='line-height:150%'>Hip arthroplasty, one of the most commonly performed surgeries in the world, faces several serious problems during its lifetime, especially lubrication degradation and/or impingement. Left untreated, this can lead to more serious problems such as chronic pain, necrosis, and ultimately, the failure of the prosthesis. Therefore, to help protect patients against such negative outcomes, a detection system is developed to help patients and physicians instantly diagnose the current structural health of hip implants and lubrication conditions. The detection system uses strategically placed Lead Zirconate Titanate (PZT) sensors on both parts of the implant for passive and active sensing of the prosthesis. The active sensing enables the system to detect the energy loss of the transmitted signal, which helps measure the thickness of the lubricant within the implant surfaces under both static and dynamic conditions. The method is validated by comparing to the lambda ratio and the Stribeck curve. The passive sensing detects <a name="_GoBack"></a>characteristic vibration and sound signature for a series of important phenomena. An ambulatory simulator is designed and built to be able to apply cyclic loading that simulates lubrication degradation and impingement. The results indicate that the sensing system is able to approximately detect the thickness of the lubricant and determine the lubrication regimes. <o:p></o:p></p><p class=MsoNormal style='line-height:normal'><b><span style='font-size:10.0pt'>Presenter: </span></b><span style='font-size:10.0pt'>Yue Yu<o:p></o:p></span></p><p class=MsoNormal style='line-height:normal'><b><span style='font-size:10.0pt'>Committee Chair: </span></b><span style='font-size:10.0pt'>Dr. Gangbing Song<o:p></o:p></span></p><p class=MsoNormal style='line-height:normal'><b><span style='font-size:10.0pt'>Committee Members: </span></b><span style='font-size:10.0pt'>Dr. Philip Noble.<o:p></o:p></span></p><p class=MsoNormal style='line-height:normal'><span style='font-size:10.0pt'> Dr. Li Sun<o:p></o:p></span></p><p class=MsoNormal style='line-height:normal'><span style='font-size:10.0pt'> Dr. Haichang Gu<o:p></o:p></span></p><p class=MsoNormal style='line-height:normal'><b><span style='font-size:10.0pt'>Venue: </span></b><span style='font-size:10.0pt'> MECE Small Conference Room<o:p></o:p></span></p><p class=MsoNormal style='line-height:normal'><b><span style='font-size:10.0pt'>Data: </span></b><span style='font-size:10.0pt'>July 29, 2011<o:p></o:p></span></p><p class=MsoNormal style='line-height:normal'><b><span style='font-size:10.0pt'>Time: </span></b><span style='font-size:10.0pt'>2:00 P.M.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;line-height:115%'><o:p> </o:p></span></p><p class=MsoNormal><o:p> </o:p></p></div></body></html>