Physical Sciences and Mathematics Commons^™

Statistical Methods With A Focus On Joint Outcome Modeling And On Methods For Fire Science, Da Zhong Xi

Electronic Thesis and Dissertation Repository

Understanding the dynamics of wildfires contributes significantly to the development of fire science. Challenges in the analysis of historical fire data include defining fire dynamics within existing statistical frameworks, modeling the duration and size of fires as joint outcomes, identifying the how fires are grouped into clusters of subpopulations, and assessing the effect of environmental variables in different modeling frameworks. We develop novel statistical methods to consider outcomes related to fire science jointly. These methods address these challenges by linking univariate models for separate outcomes through shared random effects, an approach referred to as joint modeling. Comparisons with existing …

Self-Immolative Polymers As A Degradable And Triggerable Class Of Surfactants, Siamak Keshtpour

Electronic Thesis and Dissertation Repository

Self-immolative polymers (SIPs) are degradable polymers that undergo end-to-end depolymerization upon triggering. They have potential for the development of degradable surfactants addressing human and environmental toxicity concerns associated with non-degradable surfactants, but they have not yet been investigated as surfactants. Herein, polyglyoxylamide SIPs with different pendent groups and end-caps were synthesized, envisioning they could serve as depolymerizable analogues of poly(vinyl alcohol) and its derivatives. Polyglyoxylamides with pendent hydroxyls stabilized both PEA and PLA particle suspensions. They showed the potential to undergo triggered degradation, resulting in destabilization of the suspensions. However, untriggered suspensions exhibited poor long-term stability, so further structural tuning …

Cyclization Of Peptide Structures By Creating Metal Foldamers Using 99m-Tc/Re(Co)3, Dhvani D. Oza

Electronic Thesis and Dissertation Repository

Constrained peptides have been successful as therapeutics owing to the rigidity in their framework, allowing them to have enhanced pharmacological properties. Apart from covalent bond based cyclization, constraints can be induced by cyclization using metal coordination. The metals Re and ^99mTc are one of the few metals which have not been studied in great detail for their ability to cyclize linear peptides. A tri-alanine sequence was employed in the peptide backbone due to its ability to form stable helices. In addition, another tripeptide sequence RGD, which is recognized by the integrin a_vb₃, was also used. …

An Investigation Of The Adsorption Mechanism Of An Aliphatic Nitrile (Tecflote S11) On Sulphide Mineral Surfaces., Trevor Holness

Electronic Thesis and Dissertation Repository

As grades of new base metal deposits decline and environmental restrictions on their extraction, increase, the mining industry is looking for new methods of processing minerals. This thesis, investigates the manner in which an aliphatic nitrile (TECFLOTE S11) is adsorbed onto the surface of sulphide mineral surfaces, to understand how TECFLOTE S11 can improve the extraction of base metals from their ores.

Bench tests, including micro-flotation, were conducted and their products examined by Time of Flight – Secondary Ion Mass Spectrometry (ToF-SIMS) to establish where the TECFLOTE S11 was adsorbed onto the mineral surface. The tests showed that the adsorption …

Impact Of Interlayer Cation Composition And Strongly Bound Water On Smectite ẟ²H, As Determined By A Modified Tcea Method, Nadine J. Kanik

Electronic Thesis and Dissertation Repository

Interlayer cation composition and cation hydration enthalpy can potentially affect the excess hydrogen-yield and δ²H of smectitic clays. Complexities arise from condensed atmospheric water adsorbed on the clay, as it constitutes a potential additional source of hydrogen when attempting to measure the δ²H of structural OH groups. To approach this problem, the δ²H of different cation-saturated, dried forms of six Clay Minerals Society Source Clay smectites were measured. A modified sample drying and on-line High-Temperature-Conversion-Elemental-Analysis (TCEA) Continuous-Flow-Isotope-Ratio-Mass-Spectrometry protocol, facilitated isotopic measurements. A stronger interlayer cation hydration enthalpy (Ca²⁺>Na⁺>K⁺), …

Making Sense Of Online Public Health Debates With Visual Analytics Systems, Anton Ninkov

Electronic Thesis and Dissertation Repository

Online debates occur frequently and on a wide variety of topics. Particularly, online debates about various public health topics (e.g., vaccines, statins, cannabis, dieting plans) are prevalent in today’s society. These debates are important because of the real-world implications they can have on public health. Therefore, it is important for public health stakeholders (i.e., those with a vested interest in public health) and the general public to have the ability to make sense of these debates quickly and effectively. This dissertation investigates ways of enabling sense-making of these debates with the use of visual analytics systems (VASes). VASes are computational …

Raman Spectroscopy And Synchrotron X-Ray Diffraction Study Of Lunar And Terrestrial Plagioclase Feldspar At High-Pressure And High-Temperature Conditions, Tianqi Xie

Electronic Thesis and Dissertation Repository

Plagioclase feldspar is one of the abundant minerals on the surface of the Earth, the Moon and Mars, and is also commonly found in meteorites. This dissertation seeks to better understand the phase changes in plagioclase when subjected to meteorite impact and fundamental information about impact cratering process.

Shock features in plagioclase from Mistastin Lake impact structure, Canada, and Apollo samples returned from the Moon were investigated. A series of progressive optical shock features were observed, and their Raman spectra was collected systematically. Identified shock featurs include deformed twins, planar features, and partially to completely isotropic or diaplectic glass. However, …

Mid-Infrared Studies Of Galactic Sources: Probing The Relationship Between Polycyclic Aromatic Hydrocarbons And Their Physical Environment, Collin Matthew Knight

Electronic Thesis and Dissertation Repository

Over the past 50 years, prominent mid-infrared (MIR) emission features from 3--20 $\mu$m have been observed ubiquitously in the interstellar medium (ISM) of Galactic and extragalactic sources. These emission features arise from the vibrational relaxation of polycyclic aromatic hydrocarbons (PAHs) after the absorption of a far-ultraviolet (FUV) photon. PAHs are astronomically significant in that they contain up to 15\% of the cosmic carbon inventory and play an important role in the physical and chemical processes of the ISM such as, for example, the gas heating and the ionization balance. Variations in the relative strengths of the major PAH bands can …

Clay Mineral Characterization And Production In Impact Settings: A Case Study On The Chicxulub Impact Structure, Mexico, Sarah L. Simpson

Electronic Thesis and Dissertation Repository

Impact cratering is the most ubiquitous geologic process shaping the surface of solid bodies in our Solar System. Despite their deleterious effects, impacts have the potential to initiate transient hydrothermal systems, making them attractive targets in the search for water and extraterrestrial life. The relatively low temperature nature of these environments and poor preservation state of craters on Earth leads to difficulties in determining the provenance of many alteration phases, particularly clay minerals. This becomes especially problematic on other clay-rich planetary bodies (e.g., Mars) where limited geologic information can lead to ambiguous and/or inaccurate interpretations. This thesis presents a case …

The Rearrangement And Nucleophilic Addition Of Donor-Acceptor Cyclobutane: Novel Methodologies To Access Δ-Lactones And Ring-Opened Products, Donghyun Koo

Electronic Thesis and Dissertation Repository

Donor-acceptor (D-A) cyclobutanes are a well recognized building block in synthetic organic chemistry thanks to their unique reactivity. A variety of synthetic methodologies such as cycloaddition, rearrangement, and ring-opening addition of D-A cyclobutanes have been reported. Among them, the rearrangement reactions of D-A cyclobutanes have attracted less interest compared with other methodologies as they too often require extreme reaction conditions. To further explore the rearrangement reactions of D-A cyclobutanes, in this work a ring expansion rearrangement reaction of D-A cyclobutanes analogous to the Cloke–Wilson reaction of cyclopropanes was examined. By exploiting the solvent effect in a Brønsted acid system, we …

Analytical And Computational Modelling Of The Ranque-Hilsch Vortex Tube, Nolan J. Dyck

Electronic Thesis and Dissertation Repository

The Ranque-Hilsch vortex tube (RHVT) is a simple mechanical device with no moving parts capable of separating a supply of compressed fluid into hot and cold streams through a process called temperature separation. The overall aim is to develop models which can be used to assess the temperature separation mechanisms in the RHVT, leading to a better overall understanding of the underlying physics. The introductory chapter contains a thermodynamic analysis and introduction to the flow physics, alongside three miniature literature reviews and critiques identifying research gaps.

The body of the thesis contains three articles. The first article studies the flow …

Hargraves Crater Ejecta And Implications For Impact Processes, Leah E. Sacks

Electronic Thesis and Dissertation Repository

Impact craters and their ejecta deposits offer insights into the structure and composition of planet crusts. Hargraves Crater, Mars, demonstrates an unusual balance of exposure and preservation in its ejecta. Analysing its morphologic, morphometric, thermophysical, and stratigraphic characteristics, we interpret two predominant units: an underlying ballistic lithic breccia and an overlying impact melt-bearing deposit. The lower unit is a lithic breccia composed of sub-angular, unsorted clasts (~10-12 m mean diameter), while the overlying unit is a smooth, dark toned, smaller clast-bearing (~1 m diameter at image resolution) impact melt-bearing unit with polygonal fracturing. There appears to be a sharp contact …

Exploring Explicit And Implicit Feature Spaces In Natural Language Processing Using Self-Enrichment And Vector Space Analysis, Vincent Sippola

Electronic Thesis and Dissertation Repository

Machine Learning in Natural Language Processing (NLP) deals directly with distributed representations of words and sentences. Words are transformed into vectors of real values, called embeddings, and used as the inputs to machine learning models. These architectures are then used to solve NLP tasks such as Sentiment Analysis and Natural Language Inference. While solving these tasks many models will create word embeddings and sentence embeddings as outputs. We are interested in how we can transform and analyze these output embeddings and modify our models, to both improve the task result and give us an understanding of the spaces. To this …

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 …

The Electrochemical And Corrosion Study Of Copper For Nuclear Waste Containers Under Deep Geological Disposal Conditions, Mengnan Guo

Electronic Thesis and Dissertation Repository

The proposed method for the safe disposal of Swedish, Finnish, and Canadian high-level nuclear waste (HLNW) is to isolate it in iron or steel containers with an outer copper (Cu) shell or coating and bury it in a deep geological repository (DGR). Copper has been selected as the corrosion barrier due to its stability in the aqueous anoxic environments anticipated in DGR conditions. The container will initially be exposed to humid aerated conditions which will evolve to cool and anoxic as radiation fields in the fuel decay and heat production ceases. When the DGR is cool and anoxic, sulphide (SH …

A Periglacial Landsystem Analysis In The Canadian High Arctic: A Tool For Planetary Geomorphology, Chimira Nicole Andres

Electronic Thesis and Dissertation Repository

Permafrost underlies 50% of Canada’s terrain and underlies 24% of the Earth’s total land area. It is a major driving force in the generation and evolution of patterned ground landforms such as polygons, stone circles, mud boils, and stripes, etc. that are seen on both the surface of the Earth and Mars, specifically in periglacial domains. The distribution of subsurface ice in these landforms (i.e. polygonal terrain) on Earth is a key constraint on past climate and process-form relationships in high arctic and periglacial regions. These landforms also have the potential of storing ice in the subsurface meaning that the …

Chemical Reactions At Metal Surfaces: Functionalization Strategies And Spectroscopic Characterization, Sydney Legge

Electronic Thesis and Dissertation Repository

Tremendous interest in increasing the control over surface properties has led to high demand for new efficient methods for chemical surface modifications. In this work, several approaches toward surface functionalization are explored, and modified surfaces are subsequently characterized using uniquely suited spectroscopic techniques. In the first part of this thesis, strain-promoted alkyne-azide cycloaddition (SPAAC) reactions are investigated for their potential to precisely tune the surface properties of gold substrates at the monolayer level. The utility of SPAAC reactions in preparing biorecognition interfaces for cell adhesion is then examined. Polarization modulation infrared reflection-absorption spectroscopy is used to characterize adsorbed monolayers and …

Condition And Function Of Red River Valley Streams Receiving Nutrients From Human Activities In Manitoba, Canada, Kristin J. Painter

Electronic Thesis and Dissertation Repository

Small tributary streams are conduits between the landscape and larger waterbodies and provide important ecosystem services including assimilation of nutrients from human activities which may be protective of downstream waterbodies. In the Red River Valley (RRV), Manitoba, numerous nutrient sources including agricultural runoff, livestock manure, and municipal wastewater effluent, have been attributed to the eutrophication of Lake Winnipeg and thus require targeted management to prevent loss of nutrients from land to lake. However, linkages between land-based nutrient-producing human activities in the RRV and the ecological status of the tributaries remain poorly understood. Furthermore, the proportional contribution of each source of …

Development Of A Route To Functional Polymers Via Click Chemistry, Kyle Classen

Electronic Thesis and Dissertation Repository

Functional polymers are desirable due to their use in applications such as drug delivery and bioimaging. This work describes the development of a functional polymer template, expanding upon current routes to creating functional polymer libraries. The methodology utilizes a masking-unmasking strategy to protect and then reveal a strained alkyne for the introduction of functional entities via post-polymerization modification.

The synthesis and characterization by high-resolution mass spectrometry as well as ¹H NMR, UV-Vis, and FT-IR spectroscopy of a masked strained alkyne monomer is presented. First, the strained alkyne, masked by a cyclopropenone moiety, was synthesized. Next, a norbornene derivative was …

Synthesis Of Stable Organic Radical Homo- And Co-Polymers And Their Applications In Solid-State Devices, Michael Anghel

Electronic Thesis and Dissertation Repository

This thesis outlines the synthesis and characterization of a stable organic radical homopolymer incorporating nitronyl nitroxide radicals, as well as the synthesis and characterization of random and block co-polymers incorporating nitronyl nitroxide and 6-oxoverdazyl radicals.

The nitronyl nitroxide homopolymer was synthesized using ring-opening metathesis polymerization (ROMP), yielding polymers with controlled molecular weights and narrow molecular weight distributions. Studies of polymer growth as a function of time and monomer:catalyst ratio revealed the ROMP to be well-behaved. Spectroscopic analysis of the polymer showed that the radicals possessed high radical content, indicating that they are tolerated by ROMP. Conductivity studies of thin-films made …

Hybrid Density Functionals With Proper Exact Exchange, Liyuan Ye

Electronic Thesis and Dissertation Repository

Hybrid density functionals have the best overall performance among standard density func-tional approximations (DFA). According to their original design, hybrid DFAs are supposedto use the exact exchange (EXX). However, when hybrid functionals were originally intro-duced, there was no simple method to compute EXX, so all of their practical implementationsstarted using the Hartree–Fock exchange (HFX), which can be computed easily and is simi-lar to but distinct from EXX. Recent development of an efficient method for computing EXXmade it possible to implement hybrid functionals in line with their original definition. Weimplemented EXX in the PBE0 functional and compared its performance with that …

Theoretical Investigation Of Pressure-Induced Structural Transformations Of Ethylenediamine Bisborane, Rongfeng Guan

Electronic Thesis and Dissertation Repository

High-pressure experiments on hydrogen-rich compounds provide crucial data for the rational design of hydrogen storage materials. Ethylenediamine bisborane (EDAB), BH₃·NH₂CH₂CH₂NH₂·BH₃, is one of the prime candidates for this role due to its high hydrogen content (10 wt%) and good kinetic stability under ambient conditions. Previous studies of EDAB using in situ Fourier-transform infrared (IR) spectroscopy, Raman spectroscopy, and synchrotron X-ray diffraction (XRD) techniques suggested that EDAB undergoes two possible phase transitions in the pressure range of 0 to 17 GPa. However, the crystal structures of the two new …

Effects Of Oxidative Modifications On The Structure And Non-Canonical Functions Of Cytochrome C Studied By Mass Spectrometry, Victor Yin

Electronic Thesis and Dissertation Repository

The peroxidase activity of the mitochondrial protein cytochrome c (cyt c) plays a critical role in triggering programmed cell death, or apoptosis. However, the native structure of cyt c should render this activity impossible due to the lack of open iron coordination sites at its heme cofactor. Despite its key biological importance, the molecular mechanisms underlying this structure-function mismatch remain enigmatic. The work detailed in this dissertation fills this knowledge gap by using mass spectrometry (MS) to decipher the central role that protein oxidative modifications and their associated structural changes play in activating the peroxidase function of cyt c …

Analysis Of Secondary Metabolites Biosynthesized By Pathogenic And Symbiotic Fungi Using High-Resolution Tandem Lc-Ms And Spectral Molecular Networking, Natasha Desrochers

Electronic Thesis and Dissertation Repository

Fungi from Canadian crops affect many aspects of agriculture. For example, ginseng root rot caused by Ilyonectria spp. is a major issue for farmers. Ilyonectria spp. make few reported natural products and it is not known if those products are unique to virulent species. PCA and molecular networking were applied to HRMS data to establish a distinct metabolomic profile of root rot pathogens, characterized by antifungal resorcyclic acid lactones (RALs). These likely protect Ilyonectria from other soil pathogens, which gives it the opportunity to infect ginseng root.

Molecular networking was also applied to fungal endophytes from fruit crops to identify …

Understanding The Support For Municipal Green Bin Programs, Oluwatomilola Ladele

Electronic Thesis and Dissertation Repository

As food waste increases globally, many cities have implemented curbside collection of food waste (aka green bin programs) to divert food waste from landfills. However, not all municipalities in Ontario have green bin programs. A factor responsible for the adoption of green bin programs is the community support for the program. The study results are based on 407 completed surveys from randomly selected households in London, Ontario (a municipality without a green bin program) and Kitchener-Waterloo, Ontario (a municipality with a green bin program). Surveys were used to collect data to understand: i) the predictors of household green bin support …

A Generic Implementation Of Fast Fourier Transforms For The Bpas Library, Colin S. Costello

Electronic Thesis and Dissertation Repository

In this thesis we seek to realize an efficient implementation of a generic parallel fast Fourier transform (FFT). The FFT will be used in support of fast multiplication of polynomials with coefficients in a finite field. Our goal is to obtain a relatively high performing parallel implementation that will run over a variety of finite fields with different sized characteristic primes. To this end, we implement and compare two Cooley-Tukey Six-Step fast Fourier transforms and a Cooley-Tukey Four-Step variant against a high performing specialized FFT already implemented in the Basic Polynomial Algebra Subprograms (BPAS) library. We use optimization techniques found …

A Treatise Of Pd-Lgd Correlation Modelling, Wisdom S. Avusuglo Wsa

Electronic Thesis and Dissertation Repository

The provision in Paragraph 468 of Basel II Framework Document for calculating loss given default (LGD) requires that parameters used in Pillar I of Basel II capital estimations must be reflective of economic downturn conditions so that relevant risks are accounted for. This provision is based on the fact that the probability of default (PD) and LGD correlations are not captured in the proposed formula for estimating economic capital. To help quantify economic downturn LGD, the Basel Committee proposed establishing a functional relationship between long-run and downturn LGD.

To the best of our knowledge, the current proposed models that map …

Yield-Stress Fluids In Confined Geometries, Thalia Magyar

Electronic Thesis and Dissertation Repository

A yield-stress fluid is a material that has properties of both solids and conventional liquids that only begins to flow when subject to a finite stress. The behaviour of yield-stress fluids is interesting and important in many applications. It is expected that the rheological properties of a yield-stress fluid will change when confined to a region with a length scale comparable to the characteristic scale of its microstructure. The particle size and polydispersity of two yield-stress fluids, Carbopol and poly(N-isopropylacrylamide), were determined using dynamic light scattering. A rheological characterization was performed on these two yield-stress fluids. Flow of …

Framework For Kernel Based Bm3d Algorithm, Mena Abdelrahman Massoud

Electronic Thesis and Dissertation Repository

Patch-based approaches such as Block Matching and 3D collaborative Filtering (BM3D) algorithm represent the current state-of-the-art in image denoising. However, BM3D still suffers from degradation in performance in smooth areas as well as loss of image details, specifically in the presence of high noise levels.

Integrating shape adaptive methods with BM3D improves the denoising outcome including the visual quality of the denoised image; and also maintains image details. In this study, we proposed a framework that produces multiple images using various shapes. These images were aggregated at the pixel or patch levels for both stages in BM3D, and when appropriately …

Computational Methods For Predicting Protein-Protein Interactions And Binding Sites, Yiwei Li

Electronic Thesis and Dissertation Repository

Proteins are essential to organisms and participate in virtually every process within cells. Quite often, they keep the cells functioning by interacting with other proteins. This process is called protein-protein interaction (PPI). The bonding amino acid residues during the process of protein-protein interactions are called PPI binding sites. Identifying PPIs and PPI binding sites are fundamental problems in system biology.

Experimental methods for solving these two problems are slow and expensive. Therefore, great efforts are being made towards increasing the performance of computational methods.

We present DELPHI, a deep learning based program for PPI site prediction and SPRINT, an algorithmic …