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Full-Text Articles in Mechanical Engineering
Numerical Investigation Of Subglottal Stenosis Effects On Human Voice Production, Dariush Bodaghi
Numerical Investigation Of Subglottal Stenosis Effects On Human Voice Production, Dariush Bodaghi
Electronic Theses and Dissertations
This dissertation aimed to advance knowledge of how subglottal stenosis impacts voice production physiology. An in-house fluid-structure-acoustic interaction approach based on the hydrodynamic/acoustic splitting technique was employed. This technique was rigorously verified for simulating phonation by matching the acoustic behavior to a compressible flow solver for phonation-relevant geometries. Simulations of an idealized 2D vocal tract model demonstrated the effects of supraglottal acoustic resonance on vocal fold kinematics and glottal flow waveform. Results showed that the acoustic coupling between higher harmonics and formats generated pressure oscillations, modifying vocal fold dynamics and glottal flow rate.
A major novelty was the incorporation and …
Structural And Hemodynamic Analysis Of Transcatheter Aortic Valves, Dong Qiu
Structural And Hemodynamic Analysis Of Transcatheter Aortic Valves, Dong Qiu
Electronic Theses and Dissertations
The transcatheter aortic valve replacement (TAVR) procedure has become a well-established procedure for high, intermediate-risk, and low-risk patients. However, there is limited clinical data on the TAV's long-term durability, unlike SAV devices. Computational simulations can be an alternative way to evaluate the TAV devices. This dissertation aims to conduct structural and hemodynamic analyses on the TAV devices under different conditions using computational simulation approaches.
Initially, the impact of the bicuspid aortic valve on the TAV devices was evaluated. The result indicated that the CoreValve-like supra-annular self-expandable device was likely to have increased stress and strain on the leaflet when it …
Validation Of A Two-Dimensional Clinostat Design To Provide Functional Weightlessness To Custom Gas Exchange Vessels, Collin R. Topolski
Validation Of A Two-Dimensional Clinostat Design To Provide Functional Weightlessness To Custom Gas Exchange Vessels, Collin R. Topolski
Doctoral Dissertations and Master's Theses
Understanding the impacts of microgravity on bacteria is vital for successful long duration space missions. In this environment, bacteria have been shown to become more virulent, more resistant to antibiotics and form more biofilms. To learn more about these phenomena, many experiments must be sent to the International Space Station, which is cost- and time prohibitive. Instead, the use of ground-based analogs is advantageous to define preliminary results that can later be verified with a space-based experiment. This research explored the development of an innovative 2D clinostat for simulating microgravity using bacteria. Computational fluid dynamics, standards established by previous literature …
Computational Analysis And Design Optimization Of Convective Pcr Devices, Jung Il Shu
Computational Analysis And Design Optimization Of Convective Pcr Devices, Jung Il Shu
Mechanical & Aerospace Engineering Theses & Dissertations
Polymerase Chain Reaction (PCR) is a relatively novel technique to amplify a few copies of DNA to a detectable level. PCR has already become common in biomedical research, criminal forensics, molecular archaeology, and so on. Many have attempted to develop PCR devices in numerous types for the purpose of the lab-on-chip (LOC) or point-of-care (POC). To use PCR devices for POC lab testing, the price must be lower, and the performance should be comparable to the lab devices. For current practices with the existing methods, the price is pushed up higher partially due to too much dependence on numerous developmental …
Cfd Simulation Of The Thermal Performance Of A Parallel Counter-Parallel Flow Heat Exchanger For The Treatment Of Hypothermia, Alex Heller
UNLV Theses, Dissertations, Professional Papers, and Capstones
Hypothermia is a life-threatening condition. Currently, active warming methods are the most effective treatment for dysthermic patients. The aim of this study is to investigate the use of computational fluid dynamics (CFD) in evaluating the thermal performance of a parallel/counter-parallel flow heat exchanger used as part of a fluid warmer to treat Hypothermia. The 3D model of the heat exchanger is divided into three regions; Infusate (fluid to be heated), Hot Water (heating fluid), and a Solid Region (wall). At the end of the heat exchanger, an elbow section is used to create the counter-parallel flow arrangement specific to this …