Physical Sciences and Mathematics Commons^™

Hemithioindigo-Based Photoswitchable Self- Complementary Hydrogen Bond Arrays, Suendues Noori

Electronic Thesis and Dissertation Repository

Hydrogen bonded materials are slowly conquering grounds in the literature because of their dynamic features which stem from their reversible interactions. Incorporating the ability for light to chemically modify these interactions provides a unique template for innovative, efficient and self-healing materials. This thesis explores the design, synthesis, and characterization of nine derivatives of a well-known organic compound – hemithioindigo – with dual function; as a photoswitch and a novel self-complementary hydrogen bond array. The supramolecular complexes formed moderate to strong associations (63 M^-1 to 1100 M^-1) with spontaneous Gibbs free energy values (-10.3 kJ/mol to -17.3 kJ/mol) …

Automatically Classifying Non-Functional Requirements With Feature Extraction And Supervised Machine Learning Techniques, Mahtab Ezzatikarami

Electronic Thesis and Dissertation Repository

Abstract. Context and Motivation: Non-functional requirements (NFRs) of a system need to be classified into different types such as usability, performance, etc. This would enable stakeholders to ensure the completeness of their work by extracting specific NFRs related to their expertise. Question/Problem: Because of the size and complexity of requirement specification documents, the manual classification of NFRs is time-consuming, labour-intensive, and error-prone. We thus need an automated solution that can provide a highly accurate and efficient categorization of NFRs. Principal ideas/results: In this investigation, using natural language processing and supervised machine learning (SML) techniques, we investigate with feature extraction techniques …

The Effect Of The Initial Structure On The System Relaxation Time In Langevin Dynamics, Omid Mozafar

Electronic Thesis and Dissertation Repository

In recent decades, computer experiments have allowed an accurate and fundamental understanding of molecular mechanisms at the microscopic level, such as the process of relaxation at a stable physical state. However, computer simulations may sometimes produce non-physical results or relations due to the incompleteness of mathematical models describing physical systems. In this thesis, we have investigated whether the initial structure in a computer simulation affects the system relaxation time, which is denoted by τ_sys, in the Langevin NVT ensemble. We found that for an initial structure, which is inhomogeneous in the number density of atoms, the system relaxation …

One-Pot Synthesis Of Bicyclic Piperidines From Donor Acceptor Cyclopropanes, David G. Stephens

Electronic Thesis and Dissertation Repository

The efficient synthesis of heterocyclic compounds is of great importance to organic chemistry. One method for achieving efficiency is through the use and development of one-pot reactions. This thesis describes the planning and development of an extension to the tandem cyclopropane opening Conia-ene reactivity previously reported. A search for a substrate capable of undergoing the reaction was undertaken and the reaction was optimized. The highest yielding conditions tested used catalytic Sc(OTf)₃ and superstoichiometric ZnBr₂, but other catalyst systems also worked. The optimized reaction conditions tolerated 6-membered rings well in addition to 7-membered rings in some rotationally restricted …

Regional Integration: Physician Perceptions On Electronic Medical Record Use And Impact In South West Ontario, Sadiq Raji

Electronic Thesis and Dissertation Repository

Regional initiatives in the health care context in Canada are typically organized and administered along geographic boundaries or operational units. Regional integration of Electronic Medical Records (EMR) has been continuing across Canadian provinces in recent years, yet the use and impact of regionally integrated EMRs are not routinely assessed and questions remain about their impact on and use in physicians’ practices. Are stated goals of simplifying connections and sharing of electronic health information collected and managed by many health services providers being met? What are physicians’ perspectives on the use and impact of regionally integrated EMR? In this thesis, I …

Applying Front End Compiler Process To Parse Polynomials In Parallel, Amha W. Tsegaye

Electronic Thesis and Dissertation Repository

Parsing large expressions, in particular large polynomial expressions, is an important task for computer algebra systems. Despite of the apparent simplicity of the problem, its efficient software implementation brings various challenges. Among them is the fact that this is a memory bound application for which a multi-threaded implementation is necessarily limited by the characteristics of the memory organization of supporting hardware.

In this thesis, we design, implement and experiment with a multi-threaded parser for large polynomial expressions. We extract parallelism by splitting the input character string, into meaningful sub-strings that can be parsed concurrently before being merged into a single …

Hydrothermal Alteration Footprint Of The Monument Bay Project, Manitoba, Canada, Juliana Casali

Electronic Thesis and Dissertation Repository

The Monument Bay (MB) project is a greenstone hosted gold deposit, located in NE Manitoba. Previous studies show significant gold grades in the area. This research aims to characterize and delineate the mineralogical and geochemical characteristics of the hydrothermal footprint and mineralization of MB. Combined synchrotron X-ray fluorescence, synchrotron X-ray diffraction, petrography, and electron microprobe techniques were used to support this study. Results indicate sericite and carbonate are the main hydrothermal alteration minerals with homogeneity in their mineralogical, textural, and geochemical characteristics across the deposit. Also, a strong relationship between Au, sericite alteration, and arsenopyrite grains is observed associating the …

Development Of Multi-Functional Molecular Systems For Applications On Nanomaterial Surfaces, Jun Hyeong Park

Electronic Thesis and Dissertation Repository

The glutathione-mediated, retro Michael-type addition reaction is demonstrated to take place at the interface of water-soluble, maleimide-functionalized gold nanoparticles (Maleimide-AuNP). The retro Michael-type addition can be blocked by hydrolyzing the Michael addition thioether adduct at the nanoparticle’s interface. This procedure “locks” the molecule of interest onto the Maleimide-AuNP template, ensuring no loss of the molecular cargo from the nanocarrier. On the other hand, the glutathione-mediated retro Michael-type addition reaction can be exploited for delivering a molecular payload. The Michael donor, 4-mercaptophenylacetic acid was modified with a terminal azide, allowing for addition of cargo through strain-promoted alkyne azide cycloadditions with various …

Geometallurgy And Gold Mineralization Of The Monument Bay Project, Stull Lake Greenstone Belt, Manitoba, Canada, Chunyi Hao

Electronic Thesis and Dissertation Repository

The Monument Bay Project is located in the Archean Stull Lake Greenstone Belt, in Northern Manitoba, Canada. This thesis focuses on the geometallurgy and gold mineralization of the Monument Bay Deposit in order to better understand the multiple gold mineralizing events and provide a pathfinder to gold mineralization. Traditional microscopy is used in combination with geochemical and mineralogical analytical techniques (Electron Probe Microanalysis (EPMA) and Energy-dispersive X-ray Spectroscopy (EDS)/(WDS) element map) and synchrotron geochemical techniques (synchrotron X-ray Diffraction (SR-XRD), synchrotron micro X-ray fluorescence (SR-µXRF) mapping, X-ray Absorption Near-edge Structure (XANES) Spectroscopy). Metallic gold (Au⁰) exists as free gold …

Electrochemiluminescence Of A Di-Boron Complex, Perovskite And Carbon Quantum Dots, Jonathan M. Wong

Electronic Thesis and Dissertation Repository

The electrochemiluminescence (ECL) of three novel materials was explored in this thesis. A di-boron complex exhibiting crystallization-induced blue shift emission was detected utilizing photoluminescence. This phenomenon was successfully observed in the annihilation pathway, resulting in crystallization-induced blue shift ECL. The effects of coreactant and crystallization-induced enhancements were distinguished utilizing two testing systems. Undoped and Mn-doped CsPbCl₃ perovskites were investigated, as the latter exhibits a dual emissive photoluminescence pathway due to host and dopant emission mechanics. It was discovered that the electrochemiluminescence of Mn-doped CsPbCl₃ proceeds through a triplet-triplet annihilation pathway. Furthermore, the relaxation of the electrochemically generated Mn-doped …

Fabricating Cu2znsns4, Cu2znsn(S,Se)4 And Cuin(S,Se)2 Light-Absorbing Thin Films For Low-Cost Solar Devices., Vaishnavi Raja

Electronic Thesis and Dissertation Repository

In this thesis, Cu₂ZnSnS₄ (CZTS), Cu₂ZnSn(S,Se)₄ (CZTSSe) and CuIn(S,Se)₂ (CISSe) thin-films have been optimized to use as the key light-absorbing and conversion layer for solar cells. CZTS nanocrystals (NCs) were solvothermally synthesized, etched with acetic acid and structurally analyzed using synchrotron spectroscopy. Electrodeposited CZTSSe films showed a non-ideal increase in sulfur with lower selenization temperature and post-process etching. Compositional studies of electrodeposited CISSe films confirmed the decrease in selenium after the acetic acid etching. Through PECMs and other conventional characterization techniques, it was determined that non-etched CZTSSe and CISSe solar devices performed better …

Reconstructing Carbon Dynamics Of Alpine And Temperate Zone Lakes Using Stable Isotopic Analysis, Rebecca M. Doyle

Electronic Thesis and Dissertation Repository

Lake sediments integrate signals from the catchment, atmosphere and water column, offering a unique window through which to view changes in the carbon cycle. Carbon dynamics in lakes are changing due to nitrogen loading and anthropogenic climate warming (ACW), threatening the water quality of lakes. This thesis identifies how the carbon dynamics of lakes have responded to anthropogenically-driven forcings by comparing pre- and post- AD 1850 records preserved in lake sediments. First, the carbon dynamics of Barry Lake (Ontario, Canada), a low-elevation temperate lake, are investigated. Effective moisture (the net of water inputs and evaporation) is reconstructed using the carbon …

Longitudinal Partitioning Waveform Relaxation Methods For The Analysis Of Transmission Line Circuits, Tarik Menkad

Electronic Thesis and Dissertation Repository

Three research projects are presented in this manuscript. Projects one and two describe two waveform relaxation algorithms (WR) with longitudinal partitioning for the time-domain analysis of transmission line circuits. Project three presents theoretical results about the convergence of WR for chains of general circuits.

The first WR algorithm uses a assignment-partition procedure that relies on inserting external series combinations of positive and negative resistances into the circuit to control the speed of convergence of the algorithm. The convergence of the subsequent WR method is examined, and fast convergence is cast as a generic optimization problem in the frequency-domain. An automatic …

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, …

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 …