Physics Commons^™

Effects Of Impurities On Calcium Oxalate Crystallization As Measured By Atomic Force Microscopy, Himasha Wijesekara

Electronic Thesis and Dissertation Repository

Calcium oxalate crystals are found in kidney stones as either calcium oxalate monohydrate (COM) or calcium oxalate dihydrate (COD). COM crystals are the most abundant form as they are thermodynamically more stable than COD crystals under physiological conditions. Certain aspartic acid-rich molecules such as osteopontin (OPN) are known to affect stone formation by inhibiting COM and COD growth. We have studied COM {010} and COD {100} faces in the presence of OPN, poly-aspartic acid (poly-ASP) and synthetic peptides derived from OPN to investigate the inhibitor mechanism.

We observed that poly-ASP preferentially inhibits one particular direction of {010} faces on COM …

Numerical And Semi-Analytical Estimation Of Convective Heat Transfer Coefficient For Buildings In An Urban-Like Setting, Anwar Demsis Awol

Electronic Thesis and Dissertation Repository

Urban building arrangements such as packing density, orientation and size are known to influence the microclimate surrounding each building. Studies on the impact of urban microclimatic changes on convective heat transfer coefficient (CHTC) from a stock of buildings, however, have been rare in surveyed literature. The present study focuses on numerical and analytical investigation of CHTC from building-like models with homogeneous set of equal and unequal planar and frontal densities. Consequently, the study discusses the CHTC response in relation to broader changes in the urban surface form. Part of the process involves the development of a simplified one-dimensional semi-analytical CHTC …

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 …

Numerical Simulations Of Complex Crater Formation In Layered And Mixed Targets, Ryan Hopkins

Electronic Thesis and Dissertation Repository

Numerical simulations of hypervelocity impact events provide a unique method of analyzing the mechanics that govern impact crater formation. This thesis describes modifications that were made to the impact Simplified Arbitrary Lagrangian Eulerian (iSALE) shock-physics code in order to more accurately simulate meteorite impacts into layered target sequences and details several applications that were investigated using this improved strength model.

Meteorite impacts occur frequently in layered targets but resolving thin layers in the target sequence is computationally expensive and therefore not often considered in numerical simulations. To address this limitation iSALE was modified to include an anisotropic yield criterion and …

Methodologies For Metal Functionalization Of Phosphorus Based Photopolymer Networks, Vanessa Béland

Electronic Thesis and Dissertation Repository

Photopolymer networks with phosphonium cation, alkyl phosphine and olefin functionality were designed, synthesized and functionalized with metals by metathesis, coordination and hydrometallation reactions, respectively. The materials were strategically designed so that the metal functionalization step could be monitored and quantified. In some cases, this involved characterization by IR, NMR, or X-ray spectroscopic techniques, or by comparison to molecular analogues. It was found that by using a bi-functional photopolymer network, the material could be bi-metallized by orthogonal mechanisms. All metallized polymer networks were tested for their suitability as precursors to metal-containing ceramics. The polymers were pyrolyzed, and on analysis it was …

The Effect Of Spatial Averaging On Db/Dt Exposure Values For Implanted Medical Devices, Christopher Ap Brown

Electronic Thesis and Dissertation Repository

Magnetic resonance imaging (MRI) is a medical imaging modality that has seen continuous growth in the decades since its introduction. In conjunction with this increase in the use of MRI, there has also been a growth in the number of patients having implanted medical devices, such as pacemakers. These devices can have undesirable interactions with the MR system. The safety of these interactions must be guaranteed while ensuring that safety limits are not so conservative that they would preclude too many patients from benefiting from MRI. One factor that could make limits less restrictive is spatial averaging of the fields …

Porous Membranes From 2d Materials And Their Integration Into Chemiresistive Sensors For In-Line Detection Of Cadmium In Water Filtration Devices, Sheldon Van Middelkoop

Electronic Thesis and Dissertation Repository

As the global population increases, the need for drinking water is an ever-present concern. Water contamination from cadmium needs to be avoided due to the damaging effects of Cd dications to the human health. The Environmental Protection Agency (EPA) has set an extremely low permissible limit for Cd²⁺ in water, at 5 parts-per-billion (PPB), which poses extreme challenges towards Cd²⁺ detection and retention in specific water purification devices. This has led to a rush in the development of low-cost and scalable devices with in-line Cd²⁺sensing capabilities, with the ability to simultaneously purify water and monitor its …

Development Of A 1-Dimensional Data Assimilation To Determine Temperature And Relative Humidity Combining Raman Lidar Backscatter Measurements And A Reanalysis Model, Shayamila N. Mahagammulla Gamage

Electronic Thesis and Dissertation Repository

Water vapor is the most dominant greenhouse gas in Earth's atmosphere. It is highly variable and its variations strongly depend on changes in temperature. Atmospheric water vapor can be expressed as relative humidity (RH), the ratio of the partial pressure of water vapor in the mixture to the equilibrium vapor pressure of water over a flat surface of pure water at a given temperature. Liquid water can exist as super-cooled water for temperatures between 0C to -38C. Thus, RH can be measured either relative to water (RHw) or to ice (RHi). RHi measurements are important in the upper tropospheric region, …

Calculating The Dimensionality Of The Brain, And Other Applications Of An Optimized Generalized Ising Model In Predicting Brain's Spontaneous Functions, Pubuditha M. Abeyasinghe

Electronic Thesis and Dissertation Repository

Understanding a system as complex as the human brain is a very demanding task. Directly working with structural and functional neuroimaging data has led to most of the understanding we have gained about the human brain. However, performing only the direct statistical comparisons on the empirical function and the structure does not fully explain the observed long-range functional correlations. Therefore, implementations of mathematical models to gain further understanding of the relationship between the structure and function of the brain is critical. Additionally, spontaneous functions of the brain can only be predicted using computer simulated models; which will be pivotal for …