Physical Sciences and Mathematics Commons^™

Dynamics Of Discs In A Nematic Liquid Crystal, Alena Antipova

Electronic Thesis and Dissertation Repository

In this thesis, a new way of simulating a two-way coupling between a liquid crystal and an immersed object is proposed. It can be used for objects of various geometries and can be expanded to be used for an object of any geometry. Additionally, a simple yet effective model was suggested for calculations of transmitted light through a nematic liquid crystal sample. This model allowed us to clarify the behavior of a ferromagnetic disc in a nematic liquid crystal observed in experiments and incorrectly interpreted at that time.

Our simulations have demonstrated the following: in the absence of external forces …

Inter- And Intra-Annual C And N Isotopic Variability Of C3 And C4 Grasses In A Temperate-Humid Dune Environment, Roshni R. Patel

Electronic Thesis and Dissertation Repository

Seasonal and annual variations in foliar δ¹³C and δ¹⁵N of a C₃ grass Ammophila breviligulata and a C₄ grass Calamovilfa longifolia from the sand dunes of Pinery Provincial Park in southern Ontario, Canada were investigated to assess isotopic variability at a single site within a temperate-humid climatic zone. This work quantifies seasonal δ¹³C and δ¹⁵N variation, tests for correlation of δ¹³C and δ¹⁵N with weather parameters, and evaluates the isotopic responses of these grasses to location within the dune system. Throughout the 2014 growing season, there …

An Exercise And Sports Equipment Recognition System, Siddarth Kalra

Electronic Thesis and Dissertation Repository

Most mobile health management applications today require manual input or use sensors like the accelerometer or GPS to record user data. The onboard camera remains underused. We propose an Exercise and Sports Equipment Recognition System (ESRS) that can recognize physical activity equipment from raw image data. This system can be integrated with mobile phones to allow the camera to become a primary input device for recording physical activity. We employ a deep convolutional neural network to train models capable of recognizing 14 different equipment categories. Furthermore, we propose a preprocessing scheme that uses color normalization and denoising techniques to improve …

Ground-Motion Prediction Equations For Central And Eastern North America, With Emphasis On Site Effects, Behzad Hassani

Electronic Thesis and Dissertation Repository

The works presented in this thesis are aimed at understanding and modeling earthquake ground motions in central and eastern North America (CENA), with an emphasis on the modeling of site effects. A number of approaches are taken, beginning with analysing of the observed ground-motion amplitudes with respect to a ground-motion prediction equation model (GMPE) of a well recorded region (California) (referenced empirical approach). In this work, we show that the ground-motion amplitudes of CENA earthquakes are very similar to the equivalent California values of Boore et al. (2014; BSSA14) at close distances, at low to moderate frequencies. At regional distances …

A Link Between Paediatric Asthma And Obesity: Are They Caused By The Same Environmental Conditions?, Phylicia Gonsalves

Electronic Thesis and Dissertation Repository

The highly associated paediatric conditions of asthma and overweight have seen dramatic increases over the past few decades. This thesis explored air pollution exposure as a potential underlying mechanism of co-morbid asthma and overweight among adolescents aged 12 to 18 years. Data from the Canadian Community Health Survey were merged with a database containing estimates of air pollution as assessed by particulate matter ≤ 2.5 microns (PM_2.5) concentrations at the postal code centroid in southwestern Ontario. Logistic regression was used to conduct the analysis. Adolescents were more likely to be overweight as PM_2.5 concentrations increased. There was …

The Inner Gaseous Disks Of Herbig Be Stars, Parshati Patel

Electronic Thesis and Dissertation Repository

Herbig Ae/Be stars are intermediate mass (~2 to 20M_sun) pre-main sequence stars that inherit a circumstellar disk of dust and gas from their formation phase. The region of this disk closest to the star is entirely gaseous because dust evaporates at the high temperatures there, and this gaseous region is currently poorly understood. Using non-LTE circumstellar disk codes to model the optical and near-infrared spectra of five, early-type (B0Ve to B2Ve) Herbig Be stars obtained with the Canada-France-Hawaii telescope ESPaDOnS instrument, the density structure of each inner gaseous disks was determined and estimates of the disk masses and …

Simulation Of Heterogeneous Colloidal Particles Immersed In Liquid Crystals, Setarehalsadat Changizrezaei

Electronic Thesis and Dissertation Repository

This thesis describes an investigation of interactions between colloidal particles immersed in a liquid crystal. The presence of colloidal particles in the liquid crystal distorts the director field distorted from its uniform orientation. These elastic distortions produce topological defects around the particles, which induce anisotropic interactions between them, and these anisotropic interactions can be used to manufacture non-closed packed colloidal crystals, such as diamond lattices, which are interesting in photonic applications. First, different types of liquid crystals, the mathematical tools to describe the anisotropic nature of liquid crystals, the Landau-de Gennes free-energy model to investigate the particle’s interaction, and different …

Total Synthesis Of (+)-Nemorensic Acid: En Route To (-)-Callosine, Matthew R. Vriesen

Electronic Thesis and Dissertation Repository

An intramolecular oxime ether cyclopropane annulation developed in 2008 by Kerr has been shown to form 2,5-trans and 2,5-cis pyrrolidines in a stereodivergent fashion. When the oxime ether is functionalized with an enantioenhanced α-hydroxy substitutent and a leaving group, the pyrrolizidine core of (-)-callosine can be accessed in short order. Callosine is a structurally unique pyrrolizidine alkaloid isolated from Mexican flowering plant Senecio callosus. In an effort to complete the total synthesis, the total synthesis of (+)-nemorensic acid, the necic acid component of the callosine, has been established. Attempts at appending the ansa bridge via esterification and macrolactonization are discussed.

Modelling The Impact Of Climate Change On The Polar Bear Population In Western Hudson Bay, Nicole Bastow

Electronic Thesis and Dissertation Repository

The aim of this thesis is to model the impact of climate change on polar bear populations. The first model is a discrete matrix model with time-dependent parameters, which are influenced by temperature increases. Sensitivity analysis is done on the model. Numerical simulations predict there exist several scenarios that result in polar bear extinction. When the impact of climate warming is low the population is predicted to die out in 300 years and for higher levels of impact the population can be extinct within 6. The second model is a system of continuous delay differential equations with time-dependent parameters, also …

Advanced Driving Assistance Prediction Systems, Maedeh Hesabgar

Electronic Thesis and Dissertation Repository

Future automobiles are going to experience a fundamental evolution by installing semiotic predictor driver assistance equipment. To meet these equipment, Continuous driving-behavioral data have to be observed and processed to construct powerful predictive driving assistants. In this thesis, we focus on raw driving-behavioral data and present a prediction method which is able to prognosticate the next driving-behavioral state. This method has been constructed based on the unsupervised double articulation analyzer method (DAA) which is able to segment meaningless continuous driving-behavioral data into a meaningful sequence of driving situations. Thereafter, our novel model by mining the sequences of driving situations can …

Optical Characterization Of Anisotropic Interfaces, Renjie Hou

Electronic Thesis and Dissertation Repository

The understanding of optical properties of surfaces and interfaces are critical for the development of new technologies ranging from photonics to molecular electronics. Knowing for example the orientation of molecules functionalized onto a surface yields valuable information about the macroscopic properties of the resulting surface. The optical properties can be tuned using various strategies such as molecular functionalization or patterning of meta-structures that ultimately interact with light in a rational way. Advanced optical and spectroscopy methods allowing one to probe such surfaces are therefore key to correlate properties and surface functionalization.

In this thesis, multiple approaches have been taken to …

Doped Tio2 Nanowires For Applications In Dye Sensitized Solar Cells And Sacrifical Hydrogen Production, Qasem Alsharari

Electronic Thesis and Dissertation Repository

This thesis explores the synthesis of metal oxide 1-D nanowires using a sol-gel method in supercritical carbon dioxide (sc-CO₂), as an environmental friendly enabling solvent. Porous nanowires were synthesized and their performance was tested in dye sensitized solar cell and sacrifical hydrogen production. Titanium isopropoxide (TIP) was used as a precursor for titania synthesis while copper, bismuth and indium were examined as dopants, respectively. The sol-gel reactions were catalyzed by acetic acid in CO₂ at a temperature of 60 °C and pressure of 5000 psi. It was observed that acetic acid/monomer ratio > 4 produced nanowires while a …

Synthesis And Electrochemiluminescence Of Thiophene Substituted Benzosiloles, Tyler J. B. Day

Electronic Thesis and Dissertation Repository

There has been increasing interest in the synthesis of siloles over the past 20 years due to their applications as chemoselective sensors and light emitting diodes. The standard synthesis of siloles involves a one-pot reductive cyclization followed by Negishi cross-coupling, which was modified by the Pagenkopf group to allow the synthesis of dissymmetric siloles. This modified synthesis allows siloles to be tuned to improve their fluorescent properties via varying substituents on the silole. This culminated in the synthesis of a series of 2,5-bis(thiophene)siloles with bulky silyl substituents that displayed excellent electrochemiluminescent properties.

In the past decade there has been a …

Data Smoothing Techniques: Historical And Modern, Lori L. Murray

Electronic Thesis and Dissertation Repository

Some elementary data smoothing techniques emerged during the eighteenth century. At that time, smoothing techniques consisted of simple interpolation of the data and eventually evolved into more complex modern methods. Some of the significant milestones of smoothing or graduation of population data will be described including the smoothing methods of W.F. Sheppard in the early twentieth century. Sheppard's statistical interests focused on data smoothing, the construction of mathematical tables and education. Throughout his career, Sheppard consulted Karl Pearson for advice pertaining to his statistical research. An examination of his correspondence to Pearson will be presented and his smoothing methods will …

Insights From Unsupervised Clustering And Composite Spectral Analysis Into The Physical Properties Driving Emission And Absorption In Quasar Uv/Optical Spectra, Aycha Tammour

Electronic Thesis and Dissertation Repository

Although quasar spectra appear remarkably similar, subtle systematic differences are well- known and are linked to the physical conditions in the emitting regions. This thesis char- acterizes the properties of quasar optical and UV spectral features and reveals some of their underlying physical causes by analyzing large spectroscopic datasets from the Sloan Digital Sky Survey.

We first examine the narrow-line region using four optical emission lines with a range of ionization potentials (IPs) using a sample of 16,027 quasars with redshift z ≤ 0.75. We bin the sample using the continuum luminosity and the Hβ width to constrain the accretion …

Machine Learning Of Lifestyle Data For Diabetes, Yan Luo

Electronic Thesis and Dissertation Repository

Self-Monitoring of Blood Glucose (SMBG) for Type-2 Diabetes (T2D) remains highly challenging for both patients and doctors due to the complexities of diabetic lifestyle data logging and insufficient short-term and personalized recommendations/advice. The recent mobile diabetes management systems have been proved clinically effective to facilitate self-management. However, most such systems have poor usability and are limited in data analytic functionalities. These two challenges are connected and affected by each other. The ease of data recording brings better data for applicable data analytic algorithms. On the other hand, the irrelevant or inaccurate data input will certainly commit errors and noises. The …

The Influence Of Capacity And Attitudes In The Use Of Water Quality Citizen Science And Volunteer Benthic Monitoring In The Freshwater Management Activities Of Ontario’S Conservation Authorities, Sonja Teichert

Electronic Thesis and Dissertation Repository

The contribution of non-experts to environmental management has been significant and continues to flourish through their participation in citizen science. Despite its growth as an interdisciplinary field of enquiry, there are many gaps in our understanding of the role that citizen science may play in the future of environmental management. In Ontario, Canada, due to funding cuts and infrastructural changes over the past two decades, the provincial government’s ability to monitor changes in freshwater resources had been severely limited. This has resulted in downloading water monitoring to municipalities through their conservation authorities (CAs) which are watershed-based, quasi-governmental water management agencies. …

Universal Scaling Properties After Quantum Quenches, Damian Andres Galante

Electronic Thesis and Dissertation Repository

In this Thesis, the problem of a quantum quench in quantum field theories is analyzed. This involves studying the real time evolution of observables in a theory that undergoes a change in one of its couplings. These quenches are then characterized by two parameters: $\delta \lambda$, the magnitude of the quench and most importantly, $\delta t$, the quench duration. In contrast to previous studies of abrupt quenches in the condensed matter theory community, we will be interested in smooth quenches with a finite $\delta t$.

Motivated by existing results in holographic theories, we studied the problem of a fast smooth …

Gold Mineralisation At The Fat Deposit, Courageous Lake Greenstone Belt, Northwest Territories, Canada, Marcus A. Adam

Electronic Thesis and Dissertation Repository

The Courageous Lake Greenstone Belt (CLGB) is hosted in the Yellowknife Supergroup of the Central Slave Province, NWT, Canada: a fertile gold district that includes the former Giant, Con and Lupin orogenic gold mines. The largest deposit in the CLGB is the FAT deposit, which has a proven and probable reserve of 91MT at 2.20gpt gold owned by Seabridge Gold Inc. The FAT deposit differs from other gold deposits in the Yellowknife Supergroup in that deformation and shear textures are intermittent, and where present, deformation does not correlate spatially with mineralisation. The CLGB formed as a volcanic succession that was …

Click And Bioorthogonal Chemistry For The Chemical Modification Of Nanomaterials, Pierangelo Gobbo

Electronic Thesis and Dissertation Repository

The goal of this Ph.D. thesis work is the development of novel reactive nanomaterial templates that can be chemically modified in a facile and robust (i.e., formation of covalent bonds) way for the further modification of the nanomaterial’s physical-chemical properties by the reaction partner molecular system. This type of technology was employed to further expand the application of nanomaterials in nanomedicine, chemical biology and materials science.

In order to reach this goal, as a proof of concept, small (d = 3nm) gold nanoparticles (AuNPs) and carbon nanotubes (CNT) were used as the nanomaterial substrates. Innovative synthetic strategies …

Probability Models For Health Care Operations With Application To Emergency Medicine, Azaz Bin Sharif

Electronic Thesis and Dissertation Repository

This thesis consists of four contributing chapters; two of which are inspired by practical problems related to emergency department (ED) operations management and the remaining two are motivated by the theoretical problem related to the time-dependent priority queue. Unlike classical priority queue, priorities in the time-dependent priority queue depends on the amount of time an arrival waits for service in addition to the priority class they belong. The mismatch between the demand for ED services and the available resources have direct and indirect negative consequences. Moreover, ED physician pay in some jurisdictions reflects pay-for-performance contracts based on operational benchmarks. To …

The Design And Synthesis Of Ghrelin Analogues As Non‐Invasive Ghs‐R1a Imaging Probes, Carlie L. Charlton

Electronic Thesis and Dissertation Repository

The field of molecular imaging is constantly growing and evolving in order to provide the best possible healthcare for patients in various stages of disease and therapy. Molecular imaging aims to locate specific markers of disease by selectively targeting the markers of interest with high selectivity and visualizing the accumulation using external detection. The growth hormone secretagogue receptor-1a (GHS-R1a) has been shown to be involved in various important biological functions such as energy homeostasis and cardiac contractility. GHS-R1a has shown involvement in proliferation, migration and cell invasion of specific cancer subtypes. Therefore, targeting GHS-R1a is an important marker of different …

Reframing The Mammoth Steppe: Examining Mammoth Steppe Ecology Using Carbon And Nitrogen Isotopic Compositions Of Megafauna Collagen, Rachel E. Schwartz-Narbonne

Electronic Thesis and Dissertation Repository

The Pleistocene mammoth steppe was a vast biome that stretched from northwestern Europe to central Canada. A diverse set of megaherbivore and megacarnivore species lived within this biome and there was significant ecosystem faunal and floral homogeneity. At the end of the Pleistocene, this biome disappeared, with the extinction or extirpation of many of the megafaunal species that inhabited it. This thesis reconstructs the ecology of the mammoth steppe using the isotopic compositions of carbon and nitrogen from megafaunal collagen. The reconstruction is done at a variety of ecological scales, beginning with individual animal- and season-specific isotopic studies of antlers, …

Stable Isotope Paleolimnology Of Barry Lake, Ontario, Canada Since Ad - 1268, Zijun Liu

Electronic Thesis and Dissertation Repository

The paleolimnology of Barry Lake, SE Ontario, Canada is described using mineralogy, magnetic susceptibility, carbon:nitrogen ratio, mass accumulation rates, grain-size, δ¹⁸O and δ¹³C of authigenic calcite and mollusc aragonite, δ¹³C and δ¹⁵N of organic matter, and archival records. These sediments span the Medieval Warm Period (MWP), Little Ice Age (LIA), and human settlement. Interval I proxies (AD 1268-1350, MWP) indicate warmer and drier conditions and elevated lacustrine production. Interval II (AD 1350-1615) was cooler and wetter, with lower lacustrine production and low-oxygen conditions causing loss of shelly fauna. Interval III (AD 1615-1850, …

Aerobic Oxidations Mediated By Allylnickel(N-Heterocyclic Carbene)Chloride Complexes: Investigating The Role Of A Pendent Amine Group, Richard J. Hazlehurst

Electronic Thesis and Dissertation Repository

Molecular oxygen (O₂) represents the most ideal "green" oxidant for the large-scale oxidation of organic compounds, due to its inexpensive and environmentally benign characteristics. However, a number of challenges remain for its use in the fine chemical and pharmaceutical industry, including the development of highly selective catalytic transformations. NiCl(allyl)(NHC) complexes have been shown to react with O₂ to promote the oxidation of the allylic ligand, however non-catalytically.

This report details the synthesis and characterization of novel NiCl(cinnamyl/allyl)(NHC) complexes, containing a pendent 2° amine arm on the NHC ligand to act as a hydrogen-bond donor group. The complexes …

Dissolved Organic Matter In Subarctic Streams And Rivers: Direct And Proxy Measures Of Quantity, Quality, And Mercury, Tara M. Despault

Electronic Thesis and Dissertation Repository

The drainage network of the Hudson Bay Lowlands (HBL) peatland complex regulates the transport of freshwater and solutes, including dissolved organic matter (DOM) and mercury, to Hudson Bay. Due to the remoteness and areal extent of the HBL, traditional, campaign-based sampling programs are unable to fully elucidate the region’s hydrology and biogeochemistry. This study investigated seasonal variability of DOM quantity and quality in two distinct stream orders to explore DOM sources to surface waters in the region, and assessed optical measurements as proxies for riverine DOM and mercury. In-stream primary production and enhanced microbial processing influenced DOM characteristics during base …

The Study Of Nano-Optics In Hybrid Systems, Marek J. Brzozowski

Electronic Thesis and Dissertation Repository

In this thesis, we study the quantum light-matter interaction in polaritonic heterostructures. These systems are made by combining various nanocomponents, such as quantum dots, graphene films, metallic nanoparticles and metamaterials. These heterostructures are used to develop new optoelectronic devices due to the interaction between nanocomposites.

Photoluminescence quenching and absorption spectrum are determined and an explanatory theory is developed for these polaritonic heterostructures. Photoluminescence quenching is evaluated for a graphene, metallic nanoparticle and quantum dot system. It is shown that average distance between nanocomposites or concentration of nanocomposites affect the output these system produced. Photoluminescence quenching was also evaluated for a …

Feature Encoding Strategies For Multi-View Image Classification, Kyle Doerr

Electronic Thesis and Dissertation Repository

Machine vision systems can vary greatly in size and complexity depending on the task at hand. However, the purpose of inspection, quality and reliability remains the same. This work sets out to bridge the gap between traditional machine vision and computer vision. By applying powerful computer vision techniques, we are able to achieve more robust solutions in manufacturing settings. This thesis presents a framework for applying powerful new image classification techniques used for image retrieval in the Bag of Words (BoW) framework. In addition, an exhaustive evaluation of commonly used feature pooling approaches is conducted with results showing that spatial …

Study Of Infectious Diseases By Mathematical Models: Predictions And Controls, Sm Ashrafur Rahman

Electronic Thesis and Dissertation Repository

The aim of this thesis is to understand the spread, persistence and prevention mechanisms of infectious diseases by mathematical models. Microorganisms that rapidly evolve pose a constant threat to public health. Proper understanding of the transmission machinery of these existing and new pathogens may facilitate devising prevention tools. Prevention tools against transmissions, including vaccines and drugs, are evolving at a similar pace. Efficient implementation of these new tools is a fundamental issue of public health. We primarily focus on this issue and explore some theoretical frameworks.

Pre-exposure prophylaxis (PrEP) is considered one of the promising interventions against HIV infection as …

Lagoon Wastewater Effluent Impacts Stream Metabolism In Red River Tributaries, Chris T. Chesworth

Electronic Thesis and Dissertation Repository

Lagoons are the most common form of sewage treatment for rural Canadian communities and may therefore be a major source of pollution to local waterways. However, the environmental effects of pulse releases of lagoon effluent are largely unknown. This study reports on changes in physicochemical conditions and stream metabolism occurring as result of summer lagoon effluent releases into Red River tributaries, Manitoba, Canada. We calculated metrics of stream metabolism using the single-station, open water method. We found that an effluent release results in a significant short-term increase in physicochemical (i.e., water nutrients, stream discharge) conditions which had a subsidy effect …