Physical Sciences and Mathematics Commons^™

Hot Rocks: Constraining The Thermal Conditions Of The Mistastin Lake Impact Melt Deposits Using Zircon Grain Microstructures, Gavin Douglas Tolometti, Timmons M. Erickson, Gordon R. Osinski, Cyril Cayron, Catherine Neish

Earth Sciences Publications

The production of superheated melt during hypervelocity impact events has been proposed to be a common occurrence on terrestrial planetary bodies. Recent direct evidence of superheated impact melt temperatures exceeding >2370°C from the Kamestastin (Mistastin Lake) impact structure, Canada, was based on a single impact glass sample. Such high superheated melt temperatures have strong implications for the evolution of crustal material, the thermal history of impact cratering events, and the rheology of impact melt. However, although widely predicted in previous studies, with the exception of the Mistastin Lake impact glass, there is little direct evidence for superheated temperatures in multiple …

Plasmonically-Active Nanomaterials For Enhanced Second-Harmonic Generation And Chemical Reactions, Denis Ab Therien

Electronic Thesis and Dissertation Repository

Upon excitation by an electromagnetic field, metallic nanomaterials will produce highly localized areas of electromagnetic enhancement, a phenomenon known as localized surface plasmon resonance (LSPR), which can be applied to a variety of techniques including second-harmonic generation (SHG) and surface chemistry. These tunable LSPRs can be modelled prior to fabrication by finite-difference time-domain (FDTD) calculations and observed experimentally by SHG microscopy (SHGM). In this thesis, two types of nanomaterials were characterized using SHGM: plasmon-active dendritic fractals (dendrimers) and transition-metal dichalcogenides (TMDs). Dendrimers with specific geometries and LSPRs were used to demonstrate how nanomaterial symmetry affects SHG as well as how …

Multi-Device Data Analysis For Fault Localization In Electrical Distribution Grids, Jacob D L Hunte

Electronic Thesis and Dissertation Repository

The work presented in this dissertation represents work which addresses some of the main challenges of fault localization methods in electrical distribution grids. The methods developed largely assume access to sophisticated data sources that may not be available and that any data sets recorded by devices are synchronized. These issues have created a barrier to the adoption of many solutions by industry. The goal of the research presented in this dissertation is to address these challenges through the development of three elements. These elements are a synchronization protocol, a fault localization technique, and a sensor placement algorithm.

The synchronization protocol …

Early Solar System Chronology And Isotopic Linkage Of Non-Carbonaceous Chondrules, Clasts And Achondrites, Philip M. Reger

Electronic Thesis and Dissertation Repository

Chondrules are ubiquitous igneous spherules, the main constituents of ordinary chondrites, and are considered to be critical building blocks of planetesimals, yet their age and formation mechanism(s) remain debated. Differences between ages determined from the long-lived Pb-Pb and the short-lived ²⁶Al-²⁶Mg chronometers have been attributed to the heterogeneous distribution of ²⁶Al in the solar nebula, a radionuclide that was responsible for early differentiation of planetesimals.

To evaluate this hypothesis, the ²⁶Al-²⁶Mg and the ²⁰⁷Pb-²⁰⁶Pb isotopic compositions were both measured by multi-collector ICP-MS in individual chondrules and igneous clasts in unequilibrated …

Foam-Based Floatovoltaics: A Potential Solution To Disappearing Terminal Natural Lakes, Koami Soulemane Hayibo, Joshua M. Pearce

Electrical and Computer Engineering Publications

Terminal lakes are disappearing worldwide because of direct and indirect human activities. Floating photovoltaics (FPV) are a synergistic system with increased energy output because of water cooling, while the FPV reduces water evaporation. This study explores how low-cost foam-based floatovoltaic systems can mitigate the disappearance of natural lakes. A case study is performed on 10%–50% FPV coverage of terminal and disappearing Walker Lake. Water conservation is investigated with a modified Penman-Monteith evapotranspiration method and energy generation is calculated with an operating temperature model experimentally determined from foam-based FPV. Results show FPV saves 52,000,000 m3/year of water and US$6,000,000 at 50% …

Testing Aftershock Forecasts Using Bayesian Methods, Elisa Dong

Electronic Thesis and Dissertation Repository

The presence of strong aftershocks can increase the seismic hazard following a large earthquake and should be considered for operational earthquake forecasting and risk management. Aftershock forecasts are generated from seismicity models during the evolution of the aftershock sequence. This work compares quantitative test results of the forecasting abilities for three competing aftershock rate models - the modified Omori law, the Epidemic Type Aftershock Sequence model, and the compound Omori law - to identify the best performing model for forecasting the largest aftershock during the early aftershock sequence. Forecasts of large aftershock probabilities are generated by either the Extreme Value …

Northern Tornadoes Project. Annual Report 2021 V2, The Northern Tornadoes Project

Project Reports

The Northern Tornado Project’s third year of detecting, assessing and documenting tornadoes and other damaging wind events across Canada saw some interesting extremes – tornadoes in parts of both the Atlantic and Pacific coasts for the first time in decades, an apparent absence of tornadoes on the Prairies over the 60 days with the highest climatological frequency, a record number of significant (EF2+) tornadoes in Ontario, and massive downbursts in NE British Columbia, NW Alberta and SW Northwest Territories associated with an historic ‘heat dome’.

On top of this, the COVID-19 pandemic was still spreading across the country in waves. …

Effect Of Nanoparticle Size On The Near-Surface Ph-Distribution In Aqueous And Carbonate Buffered Solutions, Thomas Stepan, Lisa Tété, Lila Laundry-Mottiar, Elena Romanovskaia, Yolanda S. Hedberg, Herbert Danninger, Michael Auinger

Chemistry Publications

An analytical solution for the effect of particle size on the current density and near-surface ion distribution around spherical nanoparticles is presented in this work. With the long-term aim to support predictions on corrosion reactions in the human body, the spherical diffusion equation was solved for a set of differential equations and algebraic relations for pure unbuffered and carbonate buffered solutions. It was shown that current densities increase significantly with a decrease in particle size, suggesting this will lead to an increased dissolution rate. Near-surface ion distributions show the formation of a steep pH-gradient near the nanoparticle surface (<6 μm) which is further enhanced in the presence of a carbonate buffer (<2 μm). Results suggest that nanoparticles in pure electrolytes not only dissolve faster than bigger particles but that local pH-gradients may influence interactions with the biological environment, which should be considered in future studies.

Location Of Cobalt Impurities In The Surface Oxide Of Stainless Steel 316l And Metal Release In Synthetic Biological Fluids, Xuying Wang, Jonas Hedberg, Heng-Yong Nie, Mark Biesinger, Inger Odnevall, Yolanda S. Hedberg

Chemistry Publications

Since 2021, cobalt (Co) is in Europe classified as carcinogen in quantities exceeding 0.1 wt-%. This affects nickel-rich stainless steels, which contain about 0.2 wt-% Co impurities. Previous findings show the bioaccessibility of Co in stainless steel to be primarily determined by the corrosion resistance. It has been unclear whether Co is distributed heterogeneously in the alloy and the outermost surface and whether a specific location would pose a risk for Co release under specific exposure conditions. This study aimed at locating Co in stainless steel 316L (0.2 wt-% Co) surfaces prior to and after exposure to different synthetic body …

Solid State Nmr Spectroscopic Characterization Of Metal Organic Frameworks, Vinicius Martins

Electronic Thesis and Dissertation Repository

Metal-organic frameworks are porous organic-inorganic materials that have attracted enormous attention due to their promising capabilities for several technologies, including carbon dioxide capture and storage, gas separation, and heterogeneous catalysis. The performance of MOFs for these applications is directly linked to their properties and, by extension, structures. Therefore, it is essential to understand the structure – property relationship. Solid-state NMR (SSNMR) spectroscopy is a technique that provides complementary information to X-ray diffraction-based techniques. SSNMR can provide short-range information around the NMR-active nucleus of interest. Furthermore, SSNMR can provide additional information regarding host-guest interactions and dynamics of adsorbed molecules, which play …

The Role Of Transient Vibration Of The Skull On Concussion, Rodrigo Dalvit Carvalho Da Silva

Electronic Thesis and Dissertation Repository

Concussion is a traumatic brain injury usually caused by a direct or indirect blow to the head that affects brain function. The maximum mechanical impedance of the brain tissue occurs at 450±50 Hz and may be affected by the skull resonant frequencies. After an impact to the head, vibration resonance of the skull damages the underlying cortex. The skull deforms and vibrates, like a bell for 3 to 5 milliseconds, bruising the cortex. Furthermore, the deceleration forces the frontal and temporal cortex against the skull, eliminating a layer of cerebrospinal fluid. When the skull vibrates, the force spreads directly to …

The Mathematics Of Risk: An Introduction To Guaranteed Data De-Identification, Kristi Thompson

Western Libraries Presentations

This webinar is devoted to the mathematical and theoretical underpinnings of guaranteed data anonymization. Topics covered include an overview of identifiers and quasi-identifiers, an introduction to k-anonymity, a look at some cases where k-anonymity breaks down, and anonymization hierarchies. The presenter will describe a method to assess a survey dataset for anonymization using standard statistical software and consider the question of "anonymization overkill". Much of the academic material looking at data anonymization is quite abstract and aimed at computer scientists, while material aimed at data curators does not always consider recent developments. This webinar is intended to help bridge the …

Physical Investigation Of Downburst Winds And Applicability To Full Scale Events, Federico Canepa

Electronic Thesis and Dissertation Repository

Thunderstorm winds, i.e. downbursts, are cold descending currents originating from cumulonimbus clouds which, upon the impingement on the ground, spread radially with high intensities. The downdraft phase of the storm and the subsequent radial outflow that is formed can cause major issues for aviation and immense damages to ground-mounted structures. Thunderstorm winds present characteristics completely different from the stationary Gaussian synoptic winds, which largely affect the mid-latitude areas of the globe in the form of extra-tropical cyclones. Downbursts are very localized winds in both space and time. It follows that their statistical investigation, by means of classical full scale anemometric …

Intra-Population Variation Of Hair And Fingernail Stable Hydrogen, Oxygen, Carbon And Nitrogen Isotopes In London, Ontario, Canada Residents During The Covid-19 Pandemic, Sawyer C E Rowe

Electronic Thesis and Dissertation Repository

Lockdowns and travel restrictions during the COVID-19 pandemic forced a significant fraction of London, Ontario, Canada residents to remain in one location for long enough to reach isotopic equilibrium with their primary drinking water source(s). This situation created ideal natural conditions for measuring the isotopic fractionation between the stable hydrogen and oxygen isotopes of drinking water and hair or nail tissues, and for determining the magnitude of intra-population variation in tissue δ²H and δ¹⁸O. Hair and nail of participants who reported exclusively drinking London municipal tap water spanned much larger δ²H and δ^{18 …}

Effects Of Glutamine Deamidation On The Oxygen Isotope Compositions Of Bone Collagen, Curtis W. Russell

Electronic Thesis and Dissertation Repository

The oxygen (O) isotope composition of mammalian collagen has the potential to provide information about the drinking water and hence geographic location and climate during the life of modern and ancient animals. An accurate and reproducible O-isotope analysis of collagen, however, has been elusive. Here, the O-isotope compositions of collagen from cortical bone of four megaherbivores were compared using two extraction procedures: the traditional Longin (HCl) method and the less commonly employed EDTA method. Preservation of O-isotope compositions was evaluated by measuring collagen peptide-chain masses, specifically the glutamine deamidation level (GDL). The EDTA method yielded collagen with a GDL of …

The Dynamical Evolution Of Classical Be Stars, Keegan Marr

Electronic Thesis and Dissertation Repository

This thesis focuses on the evolution of the disks of two classical B-emission (Be) stars, 66 Ophiuchi and Pleione, and on the thermal structure for disks tilted out of the star's equatorial plane.

We used a hydrodynamic code to model the disk of the Be star 66 Ophiuchi. Observations from 1957 to 2020 were compiled to follow the growth and subsequent dissipation of the disk. Our models are constrained by new and archival photometry, spectroscopy and polarization observations. Using Markov chain Monte Carlo methods, we confirm that 66 Oph is a B2Ve star. We constrain the density profile of the …

Electrochemical Estimations Of The Gold Nanoparticle Size Effect On Cysteine-Gold Oxidation,, E. Romanovskaia, P. Slovenský, M. Kalantarian, L. Laundry-Mottiar, V. Romanovski, M. Halama, M. Auinger, Yolanda S. Hedberg

Chemistry Publications

Gold nanoparticles are interesting for nanobiomedical applications, such as for drug delivery and as diagnostic imaging contrast agents. However, their stability and reactivity in-vivo are influenced by their surface properties and size. Here, we investigate the electrochemical oxidation of differently sized citrate-coated gold nanoparticles in the presence and absence of L-cysteine, a thiol-containing amino acid with high binding affinity to gold. We found that smaller sized (5, 10 nm) gold nanoparticles were significantly more susceptible to electrochemical L-cysteine interactions and/or L-cysteine-facilitated gold oxidation than larger (20, 50 nm) sized gold nanoparticles, both for the same mass and nominal surface area, …

Defining Service Level Agreements In Serverless Computing, Mohamed Elsakhawy

Electronic Thesis and Dissertation Repository

The emergence of serverless computing has brought significant advancements to the delivery of computing resources to cloud users. With the abstraction of infrastructure, ecosystem, and execution environments, users could focus on their code while relying on the cloud provider to manage the abstracted layers. In addition, desirable features such as autoscaling and high availability became a provider’s responsibility and can be adopted by the user's application at no extra overhead.

Despite such advancements, significant challenges must be overcome as applications transition from monolithic stand-alone deployments to the ephemeral and stateless microservice model of serverless computing. These challenges pertain to the …

What Uae Software Students Think About Software Testing: A Replicated Study, Luiz Fernando Capretz, Saad Harous, Ali Bou Nassif

Electrical and Computer Engineering Publications

Software testing is vital to improve software quality. However, software tester role is stigmatized, partly due to misperception and partly due to the treatment of the testing process within the software industry. The present study analyses this situation aiming to explore what might inhibit an individual from taking up a software testing career. In order to investigate this issue, we surveyed 132 senior students pursuing degrees in information systems, information and communication technology, computer science, computer engineering, software engineering, and other closely-related disciplines at three universities in the United Arab Emirates: two publicly funded and one top-notch private university. The …

Extremely Broad Ly Α Line Emission From The Molecular Intragroup Medium In Stephan's Quintet: Evidence For A Turbulent Cascade In A Highly Clumpy Multiphase Medium?, P. Guillard, P. N. Appleton, F. Boulanger, J. M. Shull, M. D. Lehnert, G. Pineau Des Forets, E. Falgarone, M. E. Cluver, C. K. Xu, Sarah C. Gallagher, P. A. Duc

Physics and Astronomy Publications

We present Hubble Space Telescope Cosmic Origin Spectrograph (COS) UV line spectroscopy and integral-field unit (IFU) observations of the intragroup medium in Stephan's Quintet (SQ). SQ hosts a 30 kpc long shocked ridge triggered by a galaxy collision at a relative velocity of 1000 km s-1, where large amounts of molecular gas coexist with a hot, X-ray-emitting, plasma. COS spectroscopy at five positions sampling the diverse environments of the SQ intragroup medium reveals very broad (≈2000 km s-1) Lyα line emission with complex line shapes. The Lyα line profiles are similar to or much broader than those of Hβ, [C …

Benzothiazole-Substituted Boron Difluoride Formazanate Dyes, Francis L. Buguis, Paul D. Boyle, Joe B. Gilroy

Chemistry Publications

The incorporation of benzothiazole heterocycles into existing molecular frameworks has resulted in the production of a wide range of multifunctional molecular materials. However, this strategy has not yet been explored for an emerging class of boron difluoride dyes, derived from formazanate ligands, which often exhibit tuneable redox and optical properties. Here, we address this gap in the literature and describe the synthesis and characterization of a series of benzothiazole-substituted BF­₂ formazanates. The incorporation of benzothiazole resulted in absorption profiles that were shifted to lower energies and reduction events that were shifted to more positive potentials when compared to those …

Understanding The Enumerated World: Making Sense Of Data As An Information Source, Kristi Thompson, Elizabeth Hill, Alexandra Cooper

Western Libraries Publications

Chapter in ACRL publication The Data Literacy Cookbook.

This recipe is a guide to preparing an instructional session aimed at postsecondary students in the social or health sciences or related disciplines on locating, evaluating, and using secondary data sources as information resources. Who collects data? Where can you access them? Why are data available on some topics and not others? Why are some statistics available at a detailed level of geography and others only nationally? What are some key limitations of official statistics, and where can information be found to fill in the gaps? This recipe uses these questions to …