Engineering Physics Commons^™

Improving Hydrid Pet/Mri Cardiovascular Imaging With Improved Hardware Design And Attenuation Correction Coefficient, Adam Helmy Farag

Electronic Thesis and Dissertation Repository

According to the World Health Organization (WHO) report in 2019, cardiovascular diseases (CVD) cause 52% of all illness-related deaths globally and are considered to be the second most common cause of death in Canada. CVD is also estimated to cost the Canadian economy about $21.2 billion in direct and indirect costs. With these figures, it is vital to develop the most effective and accurate methods and tools to diagnose accurately CVD and their causes. One of the promising tools for accurate diagnostic and therapeutic of CVD is the integrated Positron Emission Tomography (PET) and Magnetic Resonance Imaging (MRI) PET/MRI technology, …

Cfd Simulations Of Bubble Column Equipped With Bundles Of Concentric Tubes, Glen C. Dsouza

Electronic Thesis and Dissertation Repository

Bubble column reactors are multiphase contactors that have found several industrial applications owing to various attractive features including excellent thermal management, low maintenance cost due to simple construction and absence of moving parts. In order to attain desired performance for a given application, these reactors are usually equipped with internals such as vertical tube bundles to facilitate heat transfer. The column hydrodynamics and turbulence parameters are altered when the column is occluded with internals which adds to the complexity of the problem. The use of Computational Fluid Dynamics (CFD) tools for the study of multiphase flows has gained a lot …

Characterization And Computational Modelling For The Garnet Oxide Solid State Electrolyte Ta-Llzo, Colin A. Versnick

Electronic Thesis and Dissertation Repository

The all-solid-state-battery (ASSB) serves as a promising candidate for next generation lithium ion batteries for significant improvements in battery safety, capacity, and longevity. Of the material candidates researched to replace the conventionally used liquid electrolyte, the garnet oxide Ta-LLZO (Li_6.4La₃Zr_1.4Ta_0.6O₁₂) has received much attention thanks to its high chemical and electrochemical stability, and ionic conductivity which rivals that of liquid electrolytes. While much investigation has taken place regarding the electrochemical performance of Ta-LLZO, much less is known about the micromechanics, including microstructural characterization, stress and strain development, and material failure …

Design Of Radio-Frequency Arrays For Ultra-High Field Mri, Ian R O Connell

Electronic Thesis and Dissertation Repository

Magnetic Resonance Imaging (MRI) is an indispensable, non-invasive diagnostic tool for the assessment of disease and function. As an investigational device, MRI has found routine use in both basic science research and medicine for both human and non-human subjects.

Due to the potential increase in spatial resolution, signal-to-noise ratio (SNR), and the ability to exploit novel tissue contrasts, the main magnetic field strength of human MRI scanners has steadily increased since inception. Beginning in the early 1980’s, 0.15 T human MRI scanners have steadily risen in main magnetic field strength with ultra-high field (UHF) 8 T MRI systems deemed to …

Charging Level And Deposition Of Droplets In Electrostatic Painting, Husam Osman

Electronic Thesis and Dissertation Repository

The process of electrostatic painting has become a very important method of coating in a wide range of industrial applications including those used in the automobile industry. The general principle of spray coating is to deposit liquid droplets or solid powder particles on coated targets having various shapes. The electrostatic coating process consists of three main stages: droplet formation and charging, transportation and deposition. The complication of this process is caused by various factors, such as the physical properties of the material to be used, the appropriate electrical and mechanical conditions and the target surface to be coated, which affects …

Secondary Electrohydrodynamic Flow Generated By Corona And Dielectric Barrier Discharges, Mohammadreza Ghazanchaei

Electronic Thesis and Dissertation Repository

One of the main goals of applied electrostatics engineering is to discover new perspectives in a wide range of research areas. Controlling the fluid media through electrostatic forces has brought new important scientific and industrial applications. Electric field induced flows, or electrohydrodynamics (EHD), have shown promise in the field of fluid dynamics. Although numerous EHD applications have been explored and extensively studied so far, most of the works are either experimental studies, which are not capable to explain the in depth physics of the phenomena, or detailed analytical studies, which are not time effective. The focus of this study is …

Enhancing The Performance Of Organic Thin Film Transistors By Cross-Linking The Organic Gate Dielectric, Soheila Naderi Gohar

Electronic Thesis and Dissertation Repository

Amongst various surface modification techniques, hyperthermal hydrogen induced cross-linking (HHIC) has been used to modify the surface of polymeric samples. In this novel and innovative technique neutral hydrogen projectiles with appropriate kinetic energy are produced to generate carbon radicals on the impacted surface through the collision-induced C-H bond breaking. Subsequently, this phenomenon results in cross-linking hydrocarbon chains in the treated polymeric samples.

Verifying the validity of cross-linking process through experiments is the target of first part of presented dissertation. Spin-coated poly(methyl methacrylate) (PMMA) films on silicon wafer were exposed to hydrogen projectiles for different durations, while the other conditions related …

Fabricating Cost-Effective Nanostructures For Biomedical Applications, Erden Ertorer

Electronic Thesis and Dissertation Repository

In this thesis we described inexpensive alternatives to fabricate nanostructures on planar substrates and provided example applications to discuss the efficiency of fabricated nanostructures.

The first method we described is forming large area systematically changing multi-shape nanoscale structures on a chip by laser interference lithography. We analyzed the fabricated structures at different substrate positions with respect to exposure time, exposure angle and associated light intensity profile. We presented experimental details related to the fabrication of symmetric and biaxial periodic nanostructures on photoresist, silicon surfaces, and ion-milled glass substrates. Behavior of osteoblasts and osteoclasts on the nanostructures was investigated. These results …

Fast Absolute Quantification Of In Vivo Water And Fat Content With Magnetic Resonance Imaging, Yifan Cui

Electronic Thesis and Dissertation Repository

Quantitative water fat imaging offers a non-invasive method for monitoring and staging diseases associated with changes in either water or fat content in tissue. In this work absolute water and fat mass density measurement with in vivo Magnetic Resonance Imaging (MRI) is demonstrated. T₁ independent, T₂^* corrected chemical shift based water-fat separated images are acquired. By placing a phantom with known mass density in the field of view for signal intensity calibration, absolute water or fat mass density can be computed, assuming the B₁⁺ (transmit) and B₁^- (receive) fields can be measured. Phantom …

Preoperative Planning Of Robotics-Assisted Minimally Invasive Cardiac Surgery Under Uncertainty, Hamidreza Azimian

Electronic Thesis and Dissertation Repository

In this thesis, a computational framework for patient-specific preoperative planning of Robotics-Assisted Minimally Invasive Cardiac Surgery (RAMICS) is developed. It is expected that preoperative planning of RAMICS will improve the rate of success by considering robot kinematics, patient-specific thoracic anatomy, and procedure-specific intraoperative conditions. Given the significant anatomical features localized in the preoperative computed tomography images of a patient's thorax, port locations and robot orientations (with respect to the patient's body coordinate frame) are determined to optimize characteristics such as dexterity, reachability, tool approach angles and maneuverability. In this thesis, two approaches for preoperative planning of RAMICS are proposed that …

A Method To Measure The Detective Quantum Efficiency Of Radiographic Systems In Clinical Setting, Michael C. Mcdonald

Electronic Thesis and Dissertation Repository

The risks associated with exposure to radiation make it critical that digital imaging systems give the best possible images for a given dose to the patient. The DQE is the most widely accepted measure of performance and dose efficiency for digital radiography systems, however it is not commonly measured in a clinical environment as part of routine quality assurance. The primary reason for this is that the data provided to the user by clinical systems has typically undergone image processing and therefore may have a non-linear characteristic response. This is a problem because the Fourier metrics of the DQE require …