Physical Sciences and Mathematics Commons^™

Simulation Of Driven Elastic Spheres In A Newtonian Fluid, Shikhar M. Dwivedi

Electronic Thesis and Dissertation Repository

Simulations help us test various restrictions/assumptions placed on physical systems that would otherwise be difficult to efficiently explore experimentally. For example, the Scallop Theorem, first stated in 1977, places limitations on the propulsion mechanisms available to microscopic objects in fluids. In particular, the theorem states that when the viscous forces in a fluid dominate the inertial forces associated with a physical body, such a physical body cannot generate propulsion by means of reciprocal motion. The focus of this thesis is to firstly, explore an adaptive Multiple-timestep(MTS) scheme for faster molecular dynamics(MD) simulations, and secondly, use hybrid MD-LBM(Lattice-Boltzman Method) to test …

On Honey Bee Colony Dynamics And Disease Transmission, Matthew I. Betti

Electronic Thesis and Dissertation Repository

The work herein falls under the umbrella of mathematical modeling of disease transmission. The majority of this document focuses on the extent to which infection undermines the strength of a honey bee colony. These studies extend from simple mass-action ordinary differential equations models, to continuous age-structured partial differential equation models and finally a detailed agent-based model which accounts for vector transmission of infection between bees as well as a host of other influences and stressors on honey bee colony dynamics. These models offer a series of predictions relevant to the fate of honey bee colonies in the presence of disease …

Properties Of K-Isotropic Functions, Tianpei Jiang

Electronic Thesis and Dissertation Repository

The focus of this work is a family of maps from the space of $n \times n$ symmetric matrices, $S^n$, into the space $S^{{n \choose k}}$ for any $k=1,\ldots, n$, invariant under the conjugate action of the orthogonal group $O^n$. This family, called generated $k$-isotropic functions, generalizes known types of maps with similar invariance property, such as the spectral, primary matrix, isotropic functions, multiplicative compound, and additive compound matrices on $S^n$. The notion of operator monotonicity dates back to a work by L\"owner in 1934. A map $F :S^n \to S^m$ is called {\it operator monotone}, if $A \succeq B …

Classification With Large Sparse Datasets: Convergence Analysis And Scalable Algorithms, Xiang Li

Electronic Thesis and Dissertation Repository

Large and sparse datasets, such as user ratings over a large collection of items, are common in the big data era. Many applications need to classify the users or items based on the high-dimensional and sparse data vectors, e.g., to predict the profitability of a product or the age group of a user, etc. Linear classifiers are popular choices for classifying such datasets because of their efficiency. In order to classify the large sparse data more effectively, the following important questions need to be answered.

1. Sparse data and convergence behavior. How different properties of a dataset, such as …

Using Bolide Airwaves To Estimate Meteoroid Source Characteristics And Window Damage Potential, Nayeob Gi

Electronic Thesis and Dissertation Repository

We examined the far-field infrasonic signals produced by 78 bolides simultaneously detected by U.S. government sensors to determine the mechanisms responsible for interstation spreads in infrasound signal period. These signal period spreads lead to large variances in source energy estimates. Our analysis suggests that while acoustic source height contributes to some extent to the variance in signal periods, the range from the source to the station and in particular station noise plays a more significant role.

By simulating the near-field weak shocks from a suite of well-observed energetic fireballs, we have empirically estimated how often fireball shocks produce overpressure ( …

Enstatite Achondrites As Indicators Of Processes And Environments In The Early Solar System, Diego David Uribe

Electronic Thesis and Dissertation Repository

This thesis investigates the processes and environments of formation of the anomalous enstatite achondrites NWA 4301, Zakłodzie, and NWA 8173 to determine how they relate to other enstatite meteorites (chondrites, impact melt rocks, aubrites, and so-called “primitive enstatite achondrites”). Observations of Zakłodzie and NWA 4301 showed both meteorites may share a common parent body, but experienced different metamorphic conditions. Different zonation patterns in plagioclase, silica polymorphs and associations, and sulfide assemblages indicate Zakłodzie experienced higher metamorphic temperatures and cooled faster than NWA 4301, therefore NWA 4301 was buried deeper in the parent body relative to Zakłodzie. In NWA 8173, mineral …

Investigating Brown Dwarf Atmospheres: Gravity, Dust Content, Cloud Structure And Metallicity, Kendra Kellogg

Electronic Thesis and Dissertation Repository

Brown dwarfs are the lowest mass products of star formation. Their low masses don't allow them to sustain, or sometimes even begin, the thermonuclear processes that provide stars with internal energy and the thermal pressure necessary to maintain hydrostatic equilibrium. Thus, their radii and effective temperatures decrease as they age, continually changing their spectral classification. However, it is now a well-known fact that the spectral appearance of ultra-cool dwarfs is governed by more than just temperature. Factors such as gravity, metallicity and cloud distribution play an important role in the structure and composition of ultra-cool dwarf atmospheres and ultimately their …

Methylmercury Production In Two Northern Fen Peatlands, Mikhail J. Mack

Electronic Thesis and Dissertation Repository

Northern peatlands provide conditions favourable for sulphate reducing bacteria, microorganisms responsible for producing methylmercury, an aquatic pollutant. An expected climate driven shift from moss- to sedge-dominance may alter mercury biogeochemistry. Observations from a moss-dominated poor fen and sedge-dominated intermediate fen were used to compare methylmercury to assess if contrasting plant communities, nutrients status and/or hydrologic regime control production. Chapter 2 compared porewater methylmercury and ancillary chemistry across two Northern Ontario fens. The lower water table, greater dissolved organic carbon, and lower pH in the poor fen resulted in 3.1 times greater methylmercury. Chapter 3, riparian zones in intermediate fen were …

Signet: A Neural Network Architecture For Predicting Protein-Protein Interactions, Muhammad S. Ahmed

Electronic Thesis and Dissertation Repository

The study of protein-protein interactions (PPI) is critically important within the field of Molecular Biology, as proteins facilitate key organismal functions including the maintenance of both cellular structure and function. Current experimental methods for elucidating PPIs are greatly hindered by large operating costs, lengthy wait times, as well as low accuracy. The recent development of computational PPI predicting techniques has worked to address many of these issues. Despite this, many of these methods utilize over-engineered features and naive learning algorithms. With the recent advances in Machine Learning and Artificial Intelligence, we attempt to view this problem through a novel, deep …

Temporal Variability In The Daytime Green Roof Energy Balance During Drying Periods, Dimuth C. Kurukulaarachchi

Electronic Thesis and Dissertation Repository

Green roofs are a building design element intended to increase evaporative cooling in cities during the summer, which helps alleviate the daytime impacts of heat on human health and energy consumption, and supports mitigation and adaptation to the local effects of climate change. Time varying energy balances were measured on a 0.15 m deep, ~ 60 m² modular green roof with Sedum spurium in London, Ontario for the summer of 2014. A lysimetry approach was used to measure latent heat Q_E. Net radiation Q^* and ground heat flux Q_G were also measured, with sensible heat …

Resource Bound Guarantees Via Programming Languages, Michael J. Burrell

Electronic Thesis and Dissertation Repository

We present a programming language in which every well-typed program halts in time polynomial with respect to its input and, more importantly, in which upper bounds on resource requirements can be inferred with certainty. Ensuring that software meets its resource constraints is important in a number of domains, most prominently in hard real-time systems and safety critical systems where failing to meet its time constraints can result in catastrophic failure. The use of test- ing in ensuring resource constraints is of limited use since the testing of every input or environment is impossible in general. Static analysis, whether via the …

Using Fluid-Mobile Elements To Decipher An Aqueous History Preserved In The Sedimentary Rocks Of Gale Crater, Mars, Jeff A. Berger

Electronic Thesis and Dissertation Repository

Fluid-mobile elements preserve a record of the aqueous history of Mars in the sedimentary rocks of Gale Crater, and they are traceable with the rover Curiosity’s Alpha Particle X-ray Spectrometer (APXS). This is the fundamental principle behind the scientific questions addressed in the four main chapters of this dissertation. First, we conducted a field study at Hawai’i, an established Mars analogue, to investigate sedimentary processes and alteration in rocks comparable to those in Gale Crater. We conclude that open system, circumneutral weathering is very limited in Gale rocks; acid sulfate alteration and sedimentary mixing of diverse rocks is likely. Second, …

Structural Modification, Polymerization And Applications Of Boron Difluoride Formazanates, Stephanie M. Barbon

Electronic Thesis and Dissertation Repository

This thesis describes the synthesis and characterization of a new family of fluorescent and redox-active BF₂ complexes of formazanate [R¹-N-N=C(R³)-N=N-R⁵]⁻ ligands. The complexes were easily synthesized in two high-yielding steps, from inexpensive starting materials and readily purified by conventional methods. The properties of the resulting complexes can be tuned through structural variation – for example, appending electron donating or withdrawing substituents, or extending π conjugation. These methods of structural variation can bathochromically or hypsochromically shift the maximum absorption and emission wavelengths, vary the quantum yields, and allow for tuning of the reduction …

Molecular And Polymeric Materials Based On Asymmetrically Substituted Bf2 3-Cyanoformazanates, Samantha Novoa

Electronic Thesis and Dissertation Repository

This thesis outlines the synthesis and characterization of asymmetric and symmetric 3-cyanoformazanate BF₂ complexes and their incorporation into polymers. CuAAC chemistry was used to synthesize two additional asymmetric BF₂ complexes and a side product that was identified as a symmetric dimer. Spectroscopic and electrochemical properties of these compounds are described.

Incorporation of an asymmetric 3-cyanoformazante BF₂ complex into polymers was done by ROMP. This reaction was used to make homo, block, and random copolymers, where the comonomer was an organic norbornene derivative. Spectroscopic studies of these polymers revealed that, as the mole fraction of BF₂ (ƒ …

Evolution Of Cu2o Morphology During Copper Corrosion In The Presence Of Gamma-Radiation, Arielle M. Jean

Electronic Thesis and Dissertation Repository

In this work, experiments were carried out in order to develop a mechanistic understanding of the corrosion of copper metal in limited water volumes under gamma-radiation. When exposed to gamma-radiation, water decomposes into chemically reactive oxidizing and reducing species. Under a continuous radiation flux, the concentrations of the radiolytically produced oxidants eventually reach a pseudo-steady state that can influence the corrosion kinetics of metallic surfaces.

The evolution of the surface morphology during water droplet corrosion of copper in the presence of gamma-radiation was investigated as a function of irradiation time and pH. The oxide growth kinetics were studied by measuring …

A Chlorine-Free Protocol For Processing Silicon, Germanium, And Tin, Michael J. Krause

Electronic Thesis and Dissertation Repository

Replacing molecular chlorine and hydrochloric acid with less energy- and risk-intensive reagents would dramatically improve the environmental impact of metal manufacturing at a time when demand for metals is rapidly increasing. Germanium and tin are classified as “critical” elements based on growing demand for these elements in technological applications, lack of suitable substitutes, and, for germanium, high dispersion in the environment making extraction of the element process-intensive. This thesis describes a recyclable quinone / catechol redox platform that provides an innovative replacement for elemental chlorine and hydrochloric acid in the conversion of germanium metal or tin metal to element tetrachloride …

A Method For Hemispherical Ground Based Remote Sensing Of Urban Surface Temperatures, Michael A. Allen

Electronic Thesis and Dissertation Repository

This thesis presents a method for deriving time-continuous urban surface temperature and heat island assessments from hemispherical ground-based measurements of upwelling thermal radiation. The method, developed to overcome geometric and temporal biases inherent in traditional thermal remote sensing of urban surface climates, uses a sensor view model in conjunction with a radiative transfer code to derive atmospherically corrected, hemispherical radiometric urban surface temperatures. These are used to derive two long-term climatologies of surface urban heat island (sUHI) magnitudes for Basel, Switzerland and Vancouver, Canada. sUHI development shows significant variation based on time-of-day, season, and ambient and synoptic conditions. Results also …

Doubly Bonded Derivatives Of Si And Ge: Cycloaddition Reactions And Polymer Chemistry, Bahareh Farhadpour

Electronic Thesis and Dissertation Repository

(Di)tetrelenes are a fundamental class of unsaturated Group 14 compounds and play a central role in the synthesis of functional Group 14 compounds. The objective of this research was to investigate the various aspects of group 14 (di)tetrelenes (R₂M=ER₂, M = Si, Ge, and E = C, Si, Ge) reactivity.

The addition of a series of nitrone and nitro compounds to the group 14 (di)tetrelenes 
Mes₂Si=SiMes₂, Mes₂Ge=GeMes₂ and Mes₂Ge=CH(CH₂-t-Bu), was examined. In general, the addition of the 1,3-dipolar nitrogen oxides to the (di)tetrelene …

Quality Assessment Of The Canadian Openstreetmap Road Networks, Hongyu Zhang

Electronic Thesis and Dissertation Repository

Volunteered geographic information (VGI) has been applied in many fields such as participatory planning, humanitarian relief and crisis management because of its cost-effectiveness. However, coverage and accuracy of VGI cannot be guaranteed. OpenStreetMap (OSM) is a popular VGI platform that allows users to create or edit maps using GPS-enabled devices or aerial imageries. The issue of geospatial data quality in OSM has become a trending research topic because of the large size of the dataset and the multiple channels of data access. The objective of this study is to examine the overall reliability of the Canadian OSM data. A systematic …

Computing Limit Points Of Quasi-Components Of Regular Chains And Its Applications, Parisa Alvandi

Electronic Thesis and Dissertation Repository

Computing limit is a fundamental task in mathematics and different mathematical concepts are defined in terms of limit computations. Among these mathematical concepts, we are interested in three different types of limit computations: first, computing the limit points of solutions of polynomial systems represented by regular chains, second, computing tangent cones of space curves at their singular points which can be viewed as computing limit of secant lines, and third, computing the limit of real multivariate rational functions.

For computing the limit of solutions of polynomial systems represented by regular chains, we present two different methods based on Puiseux series …

Mining Of Primary Healthcare Patient Data With Selective Multimorbid Diseases, Annette Megerdichian Azad

Electronic Thesis and Dissertation Repository

Despite a large volume of research on the prognosis, diagnosis and overall burden of multimorbidity, very little is known about socio-demographic characteristics of multimorbid patients. This thesis aims to analyze the socio-demographic characteristics of patients with multiple chronic conditions (multimorbidity), focusing on patient groups sharing the same combination of diseases. Several methods were explored to analyze the co-occurrence of multiple chronic diseases as well as the associations between socio-demographics and chronic conditions. These methods include disease pair distributions over gender, age groups and income level quintiles, Multimorbidity Coefficients for measuring the concurrence of disease pairs and triples, and k-modes clustering …

Solving Capacitated Data Storage Placement Problems In Sensor Networks, Zhenfei Wu

Electronic Thesis and Dissertation Repository

Data storage is an important issue in sensor networks as the large amount of data collected by the sensors in such networks needs to be archived for future processing. In this thesis we consider sensor networks in which the information produced by the sensors needs to be collected by storage nodes where the information is compressed and then sent to a central storage node called the sink. We study the problem of selecting k sensors to be used as storage nodes so as to minimize the total cost of sending information from the sensors to the storage nodes and from …

Developing And Testing A Model Of Site Amplification For Southern Ontario, Sebastian Braganza

Electronic Thesis and Dissertation Repository

Commonly-applied methods to estimate ground-motion amplification for earthquake hazard applications in southern Ontario are highly generalized. Site amplification effects have typically been estimated by a parameter that is not well-known in the region, the time-averaged shear-wave velocity in the top 30 metres of soil; V_S30. Moreover, V_S30 is not well correlated with site amplification in this region. This study develops a model that can better estimate ground motions and shaking intensities in southern Ontario based on readily-available information. The model is based on a site’s peak response frequency (f_peak), which can be estimated from depth-to-bedrock. …

Machs: Mitigating The Achilles Heel Of The Cloud Through High Availability And Performance-Aware Solutions, Manar Jammal

Electronic Thesis and Dissertation Repository

Cloud computing is continuously growing as a business model for hosting information and communication technology applications. However, many concerns arise regarding the quality of service (QoS) offered by the cloud. One major challenge is the high availability (HA) of cloud-based applications. The key to achieving availability requirements is to develop an approach that is immune to cloud failures while minimizing the service level agreement (SLA) violations. To this end, this thesis addresses the HA of cloud-based applications from different perspectives. First, the thesis proposes a component’s HA-ware scheduler (CHASE) to manage the deployments of carrier-grade cloud applications while maximizing their …

Practical Attacks On Cryptographically End-To-End Verifiable Internet Voting Systems, Nicholas Chang-Fong

Electronic Thesis and Dissertation Repository

Cryptographic end-to-end verifiable voting technologies concern themselves with the provision of a more trustworthy, transparent, and robust elections. To provide voting systems with more transparency and accountability throughout the process while preserving privacy which allows voters to express their true intent.

Helios Voting is one of these systems---an online platform where anyone can easily host their own cryptographically end-to-end verifiable election, aiming to bring verifiable voting to the masses. Helios does this by providing explicit cryptographic checks that an election was counted correctly, checks that any member of the public can independently verify. All of this while still protecting one …

Methods For Improved Estimation Of Low Blood Velocities Using Vector Doppler Ultrasound, Bushra Hussain

Electronic Thesis and Dissertation Repository

Accurate estimation of low 3D blood velocities, such as near the wall in recirculation or disturbed flow regions, is important for accurate mapping of velocities to improve estimations of wall shear stress and turbulence, which are associated risk factors for vascular disease and stroke. Doppler ultrasound non-invasively measures blood-velocities but suffers from two major limitations addressed in this thesis. These are angle dependence of the measurements, which requires the knowledge of beam-to-flow angle, and the wall-filter. The high-pass wall filter that is applied to attenuate the high-intensity low-frequency signal from tissue and slowly moving vessel wall also attenuates any low …

Metalation And Structural Properties Of Apo-Metallothioneins, Gordon W. Irvine

Electronic Thesis and Dissertation Repository

Metals are required by a quarter of all proteins to achieve their biological function, whether in an active site involved in catalytic chemistry or in a structural capacity. Metals are tightly regulated at the cellular level due to their propensity to cause unwanted side reactions and to be scavenged for use by pathogens. One of the proteins involved in this regulation of metal homeostasis is metallothionein (MT) which is a small, cysteine rich protein primarily involved in the regulation of zinc and copper homeostasis and heavy metal detoxification. MT is unique in its high cysteine content (~30% of the residues), …

The Study Of Plasmonics In Nanohole Metallic Metamaterials, Kieffer J. Davieau

Electronic Thesis and Dissertation Repository

Plasmonics is the study of light-matter interaction. The interaction of incident light (photons) with surface plasmons present in metamaterials results in unique optical properties. Nanohole arrays are a metamaterial consisting of an array of sub-wavelength holes perforated in an optically thin metallic film which resides upon a dielectric material. The interaction of light with the surface plasmons present in the nanohole array leads to extraordinary optical transmission which produces resonance peaks with a higher intensity than the incident light. By changing the physical parameters of the nanohole array, such as hole size and periodicity, the resonance peaks can be tuned …

Linear And Nonlinear Dynamics Of Spin Waves In Ferromagnetic Nanowires, Zahra Haghshenasfard

Electronic Thesis and Dissertation Repository

Motivated by recent experimental developments, we present a theoretical study of some linear and nonlinear properties of spin waves in ferromagnetic nanostructures under conditions of microwave pumping. A microscopic (or Hamiltonian-based) approach is followed including terms for both the short-range exchange and the long-range dipole-dipole interactions, as well as the effects of an external magnetic field, single-ion anisotropy, biquadratic exchange and the Ruderman-KittelKasuya-Yosida interactions, as appropriate. In ultrathin films and nanowires with thickness or lateral dimensions less than about 100 nm, the discreteness of the quantized spin waves (or magnons) and their spatial distributions become modified, making it appropriate to …

Improving Long Term Stock Market Prediction With Text Analysis, Tanner A. Bohn

Electronic Thesis and Dissertation Repository

The task of forecasting stock performance is well studied with clear monetary motivations for those wishing to invest. A large amount of research in the area of stock performance prediction has already been done, and multiple existing results have shown that data derived from textual sources related to the stock market can be successfully used towards forecasting. These existing approaches have mostly focused on short term forecasting, used relatively simple sentiment analysis techniques, or had little data available. In this thesis, we prepare over ten years worth of stock data and propose a solution which combines features from textual yearly …