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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Development of a dynamic rubber prosthesis for voice restoration following laryngectomy

Khoueir, Raja. January 2009 (has links)
Loss of speech is one important factor which contributes to a decrease of life quality for patients who undergo larynx removal following for example advanced laryngeal cancer. Several devices such as the electrolarynx and the tracheo-esophageal valve prosthesis (without oscillation) have been commercialized in order to restore speech. However, such voice restoration prosthesis are still limited for certain patients. The development of a new device using a valve of variable resistance entrained by a linear electromechanical transducer was investigated as a way to produce speech for patients with total laryngectomy (ablation of vocal folds). The concept was to undertake the design of a varying air flow resistance valve, built around existing Blom-Singer valves. The oscillating valve features a spherical head making it possible to block the opening in the wall between the trachea and the esophagus in a sinusoidal periodic fashion. A physical model of the vocal tract was built and used for preliminary in-vitro verification studies. The relationship between pressure and flow rate through the valve was determined from pressure measurements. The orifice discharge coefficient of the orifice was then calculated and the parameters of a variable resistor model were identified. Radiated sound pressure produced from the change in flow rate at the valve orifice was then compared to the original voice output to assess the accuracy of the design prototype. Results showed that the forced oscillating valve prosthesis model has lower power efficiency but can produce better sound quality than the electrolarynx.
92

Effect of disc angulation on the fluid dynamics of a tilting disc mitral valve prosthesis

Mumpower, Edward Lee 05 1900 (has links)
No description available.
93

MECHANICAL ANALYSIS OF OSSEOINTEGRATED TRANSFEMORAL IMPLANT SYSTEMS

THOMPSON, MELANIE 06 April 2010 (has links)
Osseointegrated transfemoral implants have been introduced as an alternative to conventional, socket-based prostheses for above knee amputees. This method is showing great promise; however, the frequency of device failure is of concern. As a means to understand some of these failures, this study investigates the mechanical behaviour of three osseointegrated transfemoral implant systems; an in-house prototype design and two assemblies comprised of implant-grade parts provided by Integrum AB, Sweden. A series of mechanical tests were administered to evaluate the effects of tightening specifications and connection geometry on the material response, and mechanical behaviour of the assemblies. The tests included torque-elongation measurements, torque to failure tests, and strain analyses during loading. This research was carried out in an attempt to better understand the behaviour of components under loading, in order to optimize the assembly specifications and improve the useful life of the system. The results obtained confirm that the Integrum assemblies exhibit improved performance when tightened to a level beyond the current specified tightening torque of 12 Nm. Increased tightening torque provides an improved connection between components, leading to increased torque retention, decreased peak tensile strain values and a more gradual, primarily compressive distribution of strains throughout the assembly. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2009-09-29 12:14:18.438
94

Characterization of the shear stress on the aortic valve leaflet surface and its effects on cellular biosynthetic activity

Weston, Matthew W. 12 1900 (has links)
No description available.
95

Numerical simulation of steady turbulent flow through aortic trileaflet heart valves

Stevenson, Dana Marie 05 1900 (has links)
No description available.
96

Effects of matrix and phenotype on human dermal fibroblast attachment under laminar shear stress : implications for the development of tissue-engineered heart valves

Jouret, Chantal 12 1900 (has links)
No description available.
97

The effects of geometry on the flow fields in the pulmonary bifurcation : an in vitro study

Lynch, Patricia G. 12 1900 (has links)
No description available.
98

In vitro hemodynamics of valved cardiac conduits

Faughnan, Patrick Doris 05 1900 (has links)
No description available.
99

Stentless mitral valve fixation : impact on hemodynamic performance

Jensen, Morten Ølgaard Jegstrup 05 1900 (has links)
No description available.
100

A biomorphic integrated-circuit implementation of muscular contraction

Hudson, Tina Ann 08 1900 (has links)
No description available.

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