title: SWELLING AND PERMEABILITY OF COMPACTED BENTONITE WHEN HYDRATED WITH A MULTICOMPONENT HYPERSALINE PORE FLUID

contributor:
Rowe, Kerry
Brachman, Richard
Civil Engineering

subject:
Bentonite,
Bentonite sand mixture
Swell pressure
Permeability

abstract: The swelling properties and permeability of compacted bentonite when hydrated to a multicomponent, hypersaline fluid (332 g/L total dissolved solids; 6.6 mol/L ionic strength) were quantified with laboratory experiments. The model water was designed to mimic the constituents and concentrations of Cobourg limestone of the Michigan Basin to investigate its effects on the engineering properties of compacted bentonite that are relevant for the buffer and seal components in nuclear waste disposal facility. Swell pressure decreased while the permeability increased when hydrated with the model water. Swell pressure under conditions of zero volume increase showed a rapid increase to a peak swell pressure within 10 hours from the onset of hydration with the model water, followed by a continual decrease over time from further chemical interactions. Peak swell pressure when hydrated with the model water was 45% of that with deionized water, decreasing to only 10% after 1 year at a dry density of 1.6 Mg/m3. Swell pressure increased with increasing dry density of the bentonite and reducing ionic strength of the model water. The hydraulic conductivity with respect to model water was at least 110 times greater than that for deionized water (at 1.6 Mg/m3), but low hydraulic conductivity was still attained with an average of 3x10-11 m/s after 1.7 years. There was no evidence of mineralogical change of the bentonite, but cation exchange of potassium and magnesium from the model water with the natural sodium from bentonite was the dominant reason for change in properties. Flow values, local density and macropore scale imaging showed that the bentonite was able to swell to eliminate an initial radial gap corresponding to 10% of total volume, despite being hydrated and exposed to the model water for more than a year (at 1.65 and 1.8 Mg/m3). While the permeability increased relative to samples with the same initial dry density having no initial gap, good hydraulic performance was still attained for the highest initial dry density tested as its permeability increased by only 13% of that for the samples with the same final dry density but without an initial gap.

abstract: PhD


title: Traditional Ecological Knowledge and Polar Bear Co-Management in a Changing Arctic

contributor:
Pearce, Tristan
Whitelaw, Graham
Environmental Studies

rights: Queen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canada

rights: ProQuest PhD and Master's Theses International Dissemination Agreement

rights: Intellectual Property Guidelines at Queen's University

rights: This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.

subject:
Polar bear
Arctic
Climate change
Co-management
Wildlife management
Arctic climate change
Traditional Ecological Knowledge
TEK
Indigenous
Inuit
Inuit Nunangat
Canadian Arctic
Knowledge generation and transmission
Ursus maritimus
Polar bear co-management
Scoping review
Event ethnography
Environmental studies
Arctic research
Polar bear co-management

abstract: This thesis examines polar bear (Ursus maritimus) co-management in the Canadian Arctic, with a particular focus on the contributions of Inuit traditional ecological knowledge (TEK) to published literature about polar bear. A mixed methods approach was used including a scoping review of literature about Inuit TEK of polar bear and an event ethnography of an Inuit initiative to support the generation and transmission of TEK. The results of the scoping review show that published Inuit TEK about polar bear has contributed to an understanding of polar bear ecology and management for some polar bear subpopulations in the Canadian Arctic, but less is known about polar bear TEK for longer-term monitoring purposes and in relation to Inuit cultural values and beliefs. The findings of the event ethnography are that community-governed cultural programs can contribute to the partial generation and transmission of TEK among Inuit, notably for those who may not have the opportunity to do so in their daily lives. These findings are intended to inform future research about polar bear TEK by identifying knowledge gaps, and contribute to a better understanding of the role that cultural programming can play in TEK generation and transmission.

abstract: M.E.S.


title: Investigation of the Corrosion and Electrochemical Behaviour of Nickel Electrodes in Alkaline Medium and Preparation of Nickel-based Electrocatalysts for Efficient Alkaline Water Electrolysis

contributor:
Jerkiewicz, Gregory
Chemistry

subject:
electrochemistry
nickel
electrocatalysis
water electrolysis
fuel cells
nanomaterials

abstract: Nickel (Ni) and Ni-based materials are of great interest to the development of renewable energy technologies, including fuel cells and water electrolysers, due to their good stability and catalytic activity, and lower cost when compared to currently used materials (e.g platinum).  To increase the utilisation of Ni in such technologies, it is crucial to (i) expand our knowledge on interfacial Ni electrochemistry and (ii) prepare and characterize new efficient and durable Ni electrocatalysts.  This work attempts to face both challenges in a systematic manner.  The corrosion and electrochemical behaviour of polycrystalline Ni in alkaline media saturated with either N2(g), H2(g) or O2(g) was investigated using cyclic voltammetry (CV) and potentiodynamic polarization (PDP) measurements.  The CV measurements were performed using different potential windows and potential scan rates (s) (5.00 – 100 mV s–1), while the PDP measurements were performed in both the anodic and cathodic directions using s = 0.10 mV s–1.  The effect of the state of the electrode (metallic or oxidized) was also investigated in the PDP measurements.  The CV and PDP results show that the nature of the dissolved gas and the state of the electrode’s surface can significantly affect the corrosion and electrochemical behaviour of polycrystalline Ni.  The electrochemical reduction of surface Ni hydroxide species was investigated by means of CV and linear sweep voltammetry measurements.  The results indicate that, contrary to popular belief, surface β-Ni(OH)2 layers may be reduced electrochemically under specific experimental conditions.  Finally, this work presents a novel procedure for the preparation of Ni, NiCo and NiFe electrocatalysts for renewable technologies.  Nickel-based (NiX) layered double hydroxide nanoparticles (LDHNPs) were prepared by a one-step hydrothermal method using Tris-NH2 to control particle growth.  The NiX LDHNPs were mixed with a solution of a polymer template (Pluronic F127) to prepare mesoporous mixed metal oxides (MMOs) after a thermal treatment.  Both NiX LDHNPs and MMOs were characterized using standard materials science and electrochemical techniques.  All samples showed excellent catalytic activity and long-term cycling stability.  The synthesis procedure reported herein can be easily scaled-up or tailored to different reactions, highlighting the importance of this work.

abstract: PhD


title: Interrogating Resilience: Governing Disasters in Metro Manila Post-Typhoon Ondoy

contributor:
Soederberg, Susanne
Global Development Studies

subject: Resilient disaster recovery projects

subject: Urban resilience

subject: Urban poor

subject: Typhoon Ondoy

subject: Dual disaster

subject: Disaster Risk Reduction and Management (DRRM)

subject: Flooding

subject: Governance

subject: Myth-making

subject: Makati

subject: Manila

subject: Metro Manila

subject: Shadow(s) of resilience

subject: Risk redistribution

abstract:
By studying the disproportionate catastrophic effects on Manila City and Makati City caused by flooding associated with Typhoon Ondoy (international name: Ketsana) in 2009 this thesis examines how resilient disaster recovery projects in Metro Manila support state myth-making activities pursued at various scales of governance to justify the expansion of territorial control. Political authorities in Metro Manila rely on resilience discourses to legitimize resilience interventions in the aftermath of a disaster, and these interventions are often to the detriment of those most socio-environmentally vulnerable. Drawing on the dual disaster framework and perspectives from urban political ecology, this thesis concentrates on the variegated power of global urban resilience discourses and how these, in turn, impact resilient disaster recovery projects on the ground in Metro Manila.

While national government officials argue it is an obligation of the state to make the city resilient, specifically by improving and building vital infrastructure; disasters, such as typhoon flooding cannot be neatly contained within jurisdictional boundaries and tend to spill over into neighbouring regions where there are overlapping areas of authority and competing interests – as demonstrated in the cases of Manila and Makati. As such, this thesis proposes two new theoretical concepts – shadow(s) of resilience and risk redistribution - in order to provide a contextualized understanding of urban spaces prior to change and account for the complex ways in which the socio-spatial realities of urban residents are altered due to the overlapping of natural and human-made disasters. Ultimately, resilient disaster recovery projects in Metro Manila contribute to an unequal redistribution of risks and resiliencies along axes of class, obscuring the role of state actors in creating these divides.

abstract: M.A.


title: ISOTOPE GEOCHEMISTRY OF COPPER AND ZINC IN THE GEOSPHERE AND BIOSPHERE

contributor: Geological Sciences and Geological Engineering

rights: Attribution-NonCommercial-NoDerivs 3.0 United States

subject:
Mass Spectrometry
MC-ICP-MS
Chromatography
Breast cancer
Metallomics
Copper
Zinc
Isotope geochemistry
Reference materials
Human serum

abstract:
Zinc homeostasis is disrupted during the formation of breast tumours. Malignant tumours contain elevated levels of Zn (mean = 14.93 ± 11.05 μg/g) and isotopically light d66Zn values (mean = -0.40 ± 0.15 ‰) compared to histologically normal tissue adjacent to malignant tumours (pvalue = 3.4 x 10-5 and pvalue = 0.04, respectively), indicating that the processes that govern Zn accumulation in malignant tumours are fundamentally different from those that control homeostasis in healthy cells and benign tumour cells. No statistically significant difference in bulk serum Zn concentration or d66Zn value was observed between healthy controls and patients.

Serum zinc concentrations have been reported to fall by between about 10 and 25% three hours postprandial (i.e. after eating). I investigated whether this well-documented effect is accompanied by a zinc isotopic shift, with implications for study design and sampling protocols. No postprandial change in stable Zn isotope composition (mean Δ66Zn180-minute – Baseline = 0.01 ± 0.09‰, 2SD) was observed. I proposed that hemodilution and the rapid, efficient postprandial transfer of albumin-bound Zn from serum to the liver and pancreas is responsible for the lack of postprandial serum Zn isotopic response. These results indicate that studies examining solely the distribution of Zn isotopes in serum may obtain samples without considering timing of the most recent meal. However, future studies seeking to compare serum Zn concentrations with d66Zn values should draw blood samples in the morning after overnight fasting.

With the goal of expanding the number and variety of geological and biological materials that can be precisely and accurately measured, I characterized the copper isotopic compositions of ten reference materials by multiple collector inductively coupled plasma mass spectrometry using a combined standard-sample bracketing and internal normalisation mass bias correction using agallium internal standard. The reference materials measured in this thesis possess complex and ii
varied matrices with copper concentrations ranging from 1.2 μg g-1 to 497 μg g-1, and δ65Cu values ranging from -0.20‰ to 0.52‰ with an average expanded uncertainty of ± 0.07‰ (U, k = 2), covering much of the natural copper isotope variability observed in the environment.

abstract: PhD


title: Molecular-level study of N-heterocyclic carbenes: Binding modes and self-assembly on Au(111)

contributor: Physics, Engineering Physics and Astronomy

subject:
NHC
STM
Carbene
Microscopy
Self-assembly
SAM
Nanotechnology
Molecular Deposition
Intermolecular forces
UHV
Cryogenic
LabVIEW
Monte Carlo
Scanning probe microscopy
DFT

abstract:
Self-assembled monolayers (SAMs) of organic molecules are extensively used to functionalize surfaces for a wide range of applications from medicine to nanophotonics. However, creating a SAM that is sufficiently stable has been a persistent problem. Although thiols have been the gold-standard for thirty years, N-heterocyclic carbenes (NHCs) have recently been used to create SAMs that are more thermally and chemically stable. For example, NHCs based on diisopropyl benzimidazolylidene (NHCiPr) have been integrated into biosensors. The field of NHC-based material science is very new and the self-assembly mechanisms are still not well understood.

To provide a molecular-level perspective, density functional theory was combined with scanning tunneling microscopy to study the self-assembly of NHCiPr on Au(111). The isopropyl wing-tip groups of NHCiPr play an important role in the self-assembly process. They are responsible for steric interactions with the surface and for stabilizing an ordered zig-zag lattice via intermolecular CH-pi non-covalent interactions. These NHCs are bound to adatoms extracted from terraces. However, unlike other systems that have been reported, they have a relatively low diffusion rate at 77 K, and their surface transport mechanism is largely dominated by a second phase. Thermal annealing induces an irreversible conversion of the zig-zag lattice into flat-lying (NHCiPr)2Au complexes. These complexes interact weakly with the surface and diffuse with a high hopping frequency, yet they self-assemble into an ordered lattice when spatially constrained. Below a critical coverage, NHCiPr self-assembles into: an ordered phase bound directly to surface atoms, and an exotic mixed phase of surface-bound NHCiPr and (NHCiPr)2Au complexes.

The self-assembly of five other NHCs, with structurally different wing-tip groups, have also been studied in contrast to NHCiPr. In general, NHCs with sterically bulky wing-tip groups prefer to bind upright to adatoms, whereas NHCs with smaller wingtip groups prefer to form flat-lying complexes.

Through careful control of molecular coverage and surface temperature, NHCiPr forms an upright zig-zag phase, which can be readily functionalized and used in biosensors. The results presented herein provide a major step forward in understanding the mechanism for self-assembly of NHCs, a process which for thiols has taken thirty years to understand.

abstract: PhD


title: (In)visible Systemic Injustice: A Qualitative Inquiry into Women’s Experiences of Gender Discrimination in the Canadian Military

contributor:
Burfoot, Annette
Sociology

subject: Gender, Masculinity, Femininity, Inappropriate Behaviour, Sexual Misconduct, Military

abstract:
Government bodies housed in Canada are not void of their own systemic issues. The Canadian Armed Forces (CAF) is not any different possessing a traditionally gendered patriarchal white dominant culture that is resistant to the integration and inclusivity of women (Davis 2013; 2009; 2006; Deschamps 2015; Vining 2012; Gouliquer 2011). Kovitz (2018) suggests that the Canadian military is “sexualized and misogynistic” (1) and also referred to it as a “conflict zone for women” (Kovitz 2000:2). Recently, the Canadian military has been faced with several class action law suits surrounding issues regarding experiences with gender and sexual misconduct.
This qualitative, exploratory research study inductively investigates military culture highlighting the view that women in the Canadian military space continue to experience systemic issues relating to the gender power differential and systemic discrimination, lack of integration, and sexually inappropriate behaviour from members within the Canadian military. A total of 55 interviews were conducted with women who once served in the Canadian military to gain insight on these highly sensitive, yet timely systemic issues surrounding gender. These women give voice to the systemic (in)visible injustices t they faced while serving in the CAF. A Theoretical explanation, such as Social Constructionism, is superimposed on the data to help navigate a better understanding of the gendered spaces within the military and explore how issues of equality, equity and social justice are understood. Finally, recommendations and insight into policy are discussed.

abstract: PhD


title: THE MAKING OF MINORITY POLICIES IN NATIONALIZING STATES: A COMPARATIVE ANALYSIS OF ESTONIA AND ISRAEL

contributor:
Haklai, Oded
Political Studies

subject:
Ethnic Minorities
Israel
Estonia
Nationalizing States
Comparative Politics

abstract:
Why do nationalizing states, committed to preferential treatment of the dominant nation
within the state, vary in their treatment of ethnic minorities? Why do some nationalizing states
choose to simultaneously provide a certain degree of accommodation to their ethnic minorities in
some realms while excluding them from others? Under which conditions will these states decide
to shift their policy, and why? The fact that ethnic minorities experience inconsistent state
treatment across time and policy issues warrants a theoretical explanation. Presently, we know
comparatively little about the drivers of policy change in nationalizing states, and the reasons
behind the adoption of inconsistent policies, especially where they are detrimental to the
objectives of the nationalizing political elites.
This dissertation develops a theoretical framework to explain diachronic and across
policy variation toward minorities in states committed to a nationalizing agenda. The main
argument of this dissertation is that fragmentation of political authority can lead to varying
policy outcomes toward ethnic minorities in nationalizing states. At high levels of political
authority that is concentrated in the executive branch, elected officials adopt policies in
accordance with their political preferences and have the oversight capacity to determine adequate
policy outcomes. In this case, nationalist governments are likely to adopt exclusionary policies,
and minority-friendly ones, more accommodating policies. When political authority is
fragmented, additional actors become endowed with policymaking authority. Fragmentation
resulting from delegation of authority to the bureaucracy creates opportunities for entrepreneurial
and savvy bureaucrats to initiate policy diversion from the status quo policy on minority issues.
The extent to which bureaucrats are entrepreneurial and the particular characteristics of their
policymaking behaviour explain why nationalizing states, at times, employ incoherent and
inconsistent policies in relation to their minorities, especially in the absence of alternation of the
governing incumbents.
A process-tracing analysis of the policy process in Israel and Estonia toward the
Palestinian Arab and Russian-speaking minorities, respectively, is used to develop the theoretical
framework of this dissertation.

abstract: PhD


title: POST-OPERATIVE LIVER DECOMPENSATION EVENTS FOLLOWING PARTIAL HEPATECTOMY AMONG PATIENTS WITH CIRRHOSIS AND HEPATOCELLULAR CARCINOMA

contributor:
Groome, Patti
Public Health Sciences

subject:
Cancer
Epidemiology
Surgery
Hepatocellular carcinoma
Liver
Outcomes

abstract:
Background:

Partial hepatectomy, or liver resection, is a potentially-curative therapy for patients diagnosed with hepatocellular carcinoma (HCC). Because the majority of patients with HCC have pre-existing cirrhosis, pre-operative decision-making must consider severity of liver dysfunction to mitigate adverse liver-related post-operative outcomes.

Objectives:

The goals of this thesis were: 1) to critically appraise currently available prognostic models for predicting the risk of post-operative liver decompensation events (POLDEs), and 2) to identify patient-level, pre-operative predictors of POLDEs among individuals with cirrhosis and HCC undergoing liver resection.

Methods:

A systematic review of the literature was performed to identify multivariable prognostic models predicting the risk of POLDEs following liver resection. Study details regarding patients, outcomes, predictors, methodology, statistical analyses were abstracted. Studies were qualitatively assessed for risk of bias. A population-based retrospective cohort study was also conducted, of patients with cirrhosis and incident HCC diagnosed between 2007-2017 in the province of Ontario. Cox proportional hazards regression was used to identify independent predictors of POLDE-free survival, and cause-specific hazards for POLDEs and death.

Results:

In total, 36 multivariable prognostic modelling studies were identified; 25 focused on model development, 3 performed development and external validation, and 8 validated pre- existing models. Commonly used predictors in these models were serum bilirubin, platelet count, and indocyanine green retention rate at 15 minutes (ICGR15). Due to statistical and methodologic concerns, all studies were assessed a high risk of bias. In the population study, the cohort comprised 611 patients with cirrhosis and incident HCC, who subsequently underwent liver resection. Of these, 160 (26.2%) experienced at least 1 POLDE within 2 years of resection and 189 (30.9%) died in the same timeframe. Independent predictors of inferior POLDE-free survival were presence of diabetes, major liver resection, and previous non-malignant decompensation. In contrast, hepatitis B cirrhosis etiology appeared to be protective. In cause-specific analysis, the same risk factors were associated with POLDEs, except for planned extent of liver resection. Age (per year) and history of previous non-malignant decompensation were cause-specific predictors of death.

Conclusions:

Currently available multivariable prognostic models for predicting the risk of post- operative liver decompensation events following liver resection have limited validity and applicability for routine clinical use. We have identified patient and disease-related factors associated with POLDE-free survival and POLDEs, which can be used for improved patient selection and to develop prognostic tools, with the aim of improving post-operative outcomes among patients with cirrhosis and HCC.

abstract: M.Sc.


title: PROGRAMMED DEATH LIGAND 1 (PD-L1) IMMUNE CHECKPOINT-MEDIATED STIMULATION OF MALIGNANT PHENOTYPES IN TUMOUR CELLS

contributor:
Graham, Charles
Siemens, D. Robert
Biomedical and Molecular Sciences

subject:
PD-L1
Immune Escape
Drug Resistance
Autophagy
Oncogenic Signaling
Reverse Signaling
PD-1
Immune Checkpoints
Invasion
Metastasis
Breast Cancer

abstract: Most studies on the Programmed Death 1 (PD-1)/Programmed Death Ligand 1 (PD-L1) immune checkpoint have focused on elucidating the signaling mechanisms leading to inactivation of immune effectors. We, along with others, have shown that signaling by the PD-1/PD-L1 immune checkpoint may be bidirectional. Hence, we hypothesized that PD-1/PD-L1 signaling promotes malignant phenotypes in cancer cells, such as increased drug resistance as well as invasion and metastasis through the activation of oncogenic signaling pathways. This thesis aimed to (a) identify potential oncogenic signaling pathways downstream of PD-L1; (b) determine and characterise the mechanism of PD-1/PD-L1-induced drug resistance; and (c) examine the role of PD-1/PD-L1 signaling on cancer cell invasion and metastasis. Analysis of the TCGA-BRCA dataset indicated a correlation between PD-L1 expression and expression of various genes involved in oncogenic signaling and autophagy. Furthermore, Nanostring analysis of MDA-MB-231 cells treated with recombinant PD-1 (rPD-1) revealed a potential role for NOTCH1, WNT, MAPK and TGF-/SMAD signaling downstream of PD-L1. Since autophagy is a well-established mechanism of chemoresistance in cancer cells, we examined the contribution of this cellular process to PD-1/PD-L1-induced drug resistance. Findings revealed that exposure of human MDA-MB-231 breast cancer cells, but not DU-145 prostate cancer cells, to rPD-1 resulted in increased expression of key mediators of autophagy, including microtubule-associated protein 1A/1B-light chain 3 (LC3)-II, and Beclin-1, as well as increased autophagosome formation. Using autophagy inhibitors, we showed that drug resistance induced by reverse PD-1/PD-L1 signaling is causally linked to increased autophagy. In addition, results of our studies demonstrated a role for extracellular signal-related kinase (ERK) signaling in PD-1/PD-L1 induced malignant phenotypes. Blocking the ERK signaling pathway with U0126, a MEK inhibitor, inhibited rPD-1 induced LC3-II expression. Tumours from rPD-1 treated-4T1 mammary carcinoma-bearing mice also showed increased LC3-II expression. Our studies also show that MDA-MB-231 and DU-145 cells treated with rPD-1 demonstrate increased invasion, but not migration in vitro. Results of in vivo experiments did not support a role for PD-1/PD-L1 signaling in driving chemoresistance or metastasis. These studies reveal potential signaling pathways downstream of PD-L1 and provide a rationale for the use of PD-1/PD-L1 immune checkpoint blockers and autophagy inhibitors.

abstract: PhD


title: ON THE APPLICATION OF THE THEORY OF ISLAND BIOGEOGRAPHY AND ITS MODERN EXTENSIONS TO SUBMARINE BANK COMMUNITIES

contributor:
Leggett, William
Frank, Kenneth
Biology

subject:
island biogeography
ecology
theoretical ecology
marine ecology
marine biogeography
Scotian Shelf
fish
invertebrates

abstract:
This thesis explores the application of a traditionally terrestrial-based ecological theory, the Theory of
Island Biogeography (TIB), to a large marine ecosystem. Decades of testing of this theory have led to
various extensions acknowledging that the slope of the Species-Area Relationship (SAR) reflects species
traits related to dispersal capacity, and species’ competitive and predatory interactions. Until recently, it
was largely believed that marine ecosystems were too large and interconnected for this body of theory to
apply. My research indicates that this is not true. I tested the applicability of TIB and its derivatives to the
structure and dynamics of fish and macroinvertebrate communities inhabiting ten highly productive
offshore banks (ranging 500 to 10’500 km2) located on the Scotian Shelf, NW Atlantic Ocean. In Chapter
2, I found support for the TIB: there was a positive SAR for the fish species of the offshore banks. I also
found support for predictions of the Trophic TIB concerning the role of predators in controlling the SAR
of lower trophic levels: prey and mesopredator SAR slopes increased following the collapse of largebodied
predatory groundfish populations due to overfishing. In Chapter 3, I tested for a positive SAR
across the macroinvertebrate assemblages of the banks. I found a significant SAR slope only for the least
dispersive taxon, supporting early predictions of a negative relation between dispersal capacity and SAR
slope. I also found that oceanographic processes play an important role in connecting these assemblages,
most-so for highly dispersive taxa. In Chapter 4, across the fish assemblages of the banks, I found support
for the original predictions of TIB that, on average over the long-term, bank-specific colonization and
extinction events are at equilibrium. However, I also found a dramatic increase in interannual turnover of
prey fish species following predator collapse, particularly on the coldest, largest banks, suggesting an
extension of the Trophic TIB linking increased SAR slopes to reduced temporal stability may be
warranted. My research supports the continued application of TIB and its modern derivatives in large
marine ecosystems to elucidate variation of insularity and temporal stability among species assemblages
under different disturbance regimes.

abstract: PhD


title: Modelling Stock Market Manipulation in Online Forums

contributor:
Skillicorn, David
Computing

subject:
Market Manipulation
Machine Learning
Online Forums

abstract: Over the past several decades, advances in technology have significantly impacted all aspects of the financial system. While it has led to numerous benefits, it has also increased the methods for manipulating the market. A frequent platform used to perform these market manipulation schemes has been through social media. In particular, online forums have become a tool for manipulators to disseminate false or misleading information so that they can profit from other investors. As a result, my research provides investors with valuable insights and the tools necessary for detecting pump-and-dump schemes. To achieve this, posts and comments within financial forums were first collected. Then, financial data was added to associate the texts with resulting market behaviours. By using statistical methods, the records were then initially labelled depending on whether they exhibited a known market pattern that commonly occurs when investors act upon deceptive content. To further improve upon the labelling method, comments of deceptive posts were then relabelled based on their level of agreement to fraudulent information. With the described agreement model, results showed that predictions among the tested classification techniques (XGBoost, Random Forest, SVM, MLP, CNN, BiLSTM) were improved. Additionally, by comparing the performance of the classifiers, CNNs were found to be the best performing model among those that were tested.

abstract: M.Sc.


title: The Sources of Solidarity: Negotiating the Horizons of Indigenous-State Relations between Moderate and Radical Views

contributor:
Sypnowich, Christine
Philosophy

subject:
Charles Taylor
Dale Turner
Glen Coulthard
Eve Tuck
K. Wayne Yang
Pablo Gilabert
Decolonization
Social Justice
Dignitarian Approach
Indigenous
Canada

abstract: The following thesis is concerned with articulating the ways to reconcile moderate and radical views of Indigenous-state relations and finding compatible sources of solidaristic support between those endeavours. Moderate top-down statism (the moderate view) is represented by Charles Taylor and Dale Turner, and it holds that relations between Indigenous peoples and the state be maintained and fostered through careful dialogue. The state acts as the main top-down thoroughfare which policy and social change concerning Indigenous peoples happen. Radical bottom-up anti-capitalist solidarity (the radical view) is represented by Glen Coulthard, Eve Tuck, and K. Wayne Yang. It maintains that continued state relations only perpetuate the colonial and capitalist relationship between Indigenous peoples and the state, so it is necessary for Indigenous peoples to turn away from the state in an act of self-recognition, affirmation, and Indigenous resurgence, causing social change and solidarity to happen from the bottom up. Yet the radical view holds that the sources of solidarity for decolonization are incommensurable with frameworks of social justice, severely limiting legitimate forms of solidarity towards decolonial ends. Pablo Gilabert’s dignitarian approach and its concepts of solidaristic empowerment and the basis of dignity will be used to attempt to reconcile the moderate and radical views, both of which can be framed under dignitarian concerns. The argumentative conclusions of this thesis are (1) a pluralistic notion of solidarity is needed, (2) notions of justice which aim to expand the general population’s imagination can come from varied sources to (3) make the challenging demands of decolonization more receptive and (4) indicate what “social justice” can become. This happens along a temporal arc of social transformation and a Gadamerian fusion of horizons, expanding the imagination and the sources of solidaristic support.

abstract: M.A.


title: Generalized Loss Functions for Generative Adversarial Networks

contributor:
Alajaji, Fady
Gharesifard, Bahman
Mathematics and Statistics

subject:
Unsupervised learning
Generative models
Machine learning
Artificial intelligence
Optimization
Information theory

abstract:
This thesis investigates the use of parameterized families of information-theoretic measures to generalize the loss functions of generative adversarial networks (GANs) under the objective of improving performance. A new generator loss function, called least kth-order GAN (LkGAN), is introduced, generalizing the least squares GANs (LSGANs) by using a kth order absolute error distortion measure with k greater than or equal to 1 (which recovers the LSGAN loss function when k=2). It is shown that minimizing this generalized loss function under an (unconstrained) optimal discriminator is equivalent to minimizing the kth-order Pearson-Vajda divergence.

A novel loss function for the original GANs using Renyi information measures with parameter alpha is next presented. The GAN's generator loss function is generalized in terms of Renyi cross-entropy functionals. For any alpha > 0, this generalized loss function is shown to preserve the equilibrium point satisfied by the original GAN loss based on the Jensen-Renyi divergence, a natural extension of the Jensen-Shannon divergence. It is also proved that the Renyi-centric loss function reduces to the original GANs loss function as alpha approaches 1.

Experimental results implemented on the MNIST and CelebA datasets under both DCGANs and StyleGANs architectures, indicate that the proposed LkGAN and RenyiGAN systems confer performance benefits by virtue of the extra degrees of freedom provided by the parameters k and alpha, respectively. More specifically, experiments show improvements with regard to the quality of the generated images as measured by the Frechet Inception Distance (FID) score and demonstrated by training stability and extensive simulations.

abstract: M.A.Sc.


title: Temperature Dependent Emission of Acrylic Relative to Tetrapheynl Butadiene (TPB)

subject:
dark matter
particle physics
astroparticle physics
pmma

abstract:
After decades of astronomical observation and study, the majority of mass in the universe is known to be composed of dark matter, an unknown substance which is strictly non-luminous unlike the more familiar baryonic matter. Efforts to detect the elusive dark matter include low background particle detectors, which use the natural environment and precise technologies to try and observe interactions of a Standard Model particle with a dark matter particle. These are able to set limits on characteristics of dark matter particles based on their specific experiment.
For these sensitive searches, materials that are not traditionally considered to have background contributions can produce nuisance signals. Poly(methyl methacrylate) (PMMA), or acrylic, is one such material. In other fields, acrylic is known to have low level fluorescence emissions, produced by microscopic impurities from surface handling or manufacturing additives.
This work aims to characterize the magnitude of fluorescence emissions from acrylic from 300.0K to 4.0K, relative to 1,1,4,4-tetraphenyl-1,3-butadiene (TPB), a wavelength shifter commonly used in rare event detectors. Since the fluores- cence is expected to be produced by impurities, this work studies a specific batch of acrylic produced by Reynold’s Polymer Technologies (RPT) for the DEAP-3600 experiment acrylic vessel. Limits on any amount of fluorescence from the acrylic can allow the DEAP-3600 collaboration to more accurately model the overall detector response, which in turn maximizes sensitivity. The samples studied consist of one blank RPT sample with sanded sides, and an identically shaped RPT sample coated with (1.040 ± 0.052)μm of TPB on one side. They were exposed to 280.0nm UV light, which was chosen to better simulate the effect Cherenkov radiation may have on acrylic.
Emissions from the blank sample were found to be (0.5 ± 0.1)% relative to the emissions from the TPB coated sample, under the same conditions, integrated over a 50.0ns window. This value was consistent with the one measured at the boiling temperature of liquid argon (87.0K). Photons from the blank sample were emitted in the lower visible regime, rising around 375.0nm, consistent for all temperatures. Each sample showed a trend of increasing emissions at decreasing temperatures.

abstract: M.Sc.


title: Examining the Impact of the Transformational Coaching Workshop on Factors that Influence Behaviour Change

contributor:
Côté, Jean
Kinesiology and Health Studies

subject:
coaching
coach development
behaviour change
transformational coaching workshop
COM-B model

abstract:
Coach development programs (CDPs) provide an avenue for coaches to learn about the valuable knowledge and skills necessary to facilitate positive athlete outcomes through their behaviours. However, existing evidence-informed, interpersonal-focused CDPs lack in their incorporation of behaviour change theory (Allan et al., 2017). One program that exists that addresses the aforementioned limitation is the Transformational Coaching Workshop (TCW; Turnnidge & Côté, 2017). A recent evaluation of the TCW yielded promising findings in regard to the workshop’s ability to change the observable leadership behaviours of coaches (Lawrason et al., 2019); however, the TCW has not been examined for its ability to change the way coaches perceive their use of transformational coaching behaviours. Thus, the purpose of this study was to use behaviour change theory to examine the TCW’s ability to target the perceptual elements that influence behaviour change in coaches.
	Sixty-three youth sport coaches from across Ontario participated in the study. Thirty-one coaches participated in the TCW and served as the intervention group while the remaining 32 coaches served as a comparison group and did not receive any training. All coaches were asked to complete a capability-opportunity-motivation-behaviour (COM-B; Michie et al., 2011) questionnaire at two separate time points to assess their perceptions of factors that contribute to their use of transformational coaching behaviours. A combination of dependent- and independent- samples t-tests were run to examine pre- and post-test differences within the intervention group and between the intervention and comparison groups at post-test.
 	Results of the study unveiled that while the TCW increased the mean scores of coaches’ perceived capability (p = .02), opportunity  (p = .03), and motivation (p = .34) to use transformational coaching behaviours after participation in the workshop, non-significant p values after a Bonferroni adjustment (i.e., p = .01) suggest the need for a larger sample to be included in future studies of the TCW to achieve statistical significance. However, medium to large effect sizes observed for both perceived capability (d = .53) and opportunity (d = .51) offer a pragmatic understanding of the workshop’s implications on coaches who participated. Additionally, there were no significant differences between the intervention and comparison group at post-test for perceived capability, opportunity, or motivation. Nonetheless, the TCW did yield promising results for increasing the ways coaches perceive their use of transformational coaching behaviours and thus, is considered a valuable resource for youth sport coaches looking to increase the interpersonal side of their coaching.

abstract: M.Sc.


title: Generalization of a Constraint Based Intrusion Detection System

contributor:
Dean, Dr. Thomas R.
Electrical and Computer Engineering

subject:
IDS
DSL
TXL
Generalization
Constraint Based

abstract:
In a world rampant with cyber crime, Intrusion Detection System(IDS) provides an effective way to grapple with cyber attacks. An IDS is used to monitor the network traffic and generate alerts for any malicious activities detected. In the IDS designed by our research group, we provide the network constraints as a pattern that defines the network packet sequence and network behavior under an attack-free environment. Any deviation to this pattern is detected by the IDS and a network alert is generated.

This specification of constraints is done using a Domain Specific Language(DSL). The DSL that was earlier used as part of our IDS framework was a prototype designed by Hasan et al. Though effective, it had shortcomings. For instance, it worked on limited constraint specific patterns only. Secondly, it did not support use of domain information not available in the packets. Furthermore, it was limited to specifying the constraints only at the network level.

Thus due to the limitations of the previous DSL, we have extended the DSL so that it could work against a wide variety of patterns. The new DSL is designed to be more readable and easy to use for specifying constraints. It has also been effective increasing the operator support for the purpose of evaluation of the constraints and provides an easy look-up mechanism for domain information stored by the system. This newly designed DSL can be used to specify constraints at the application data level along with the network level, thus providing the option to specify constraints to read-write network data to a file. The source transformation language TXL, has been used to generate C code as the output of the extended DSL. The constraint engine of the IDS framework runs this C code to detect any anomaly within the network packets. We have devised a two-step mechanism to ensure that the C code generated is accurate. In this process we run the code against, first the packet capture(pcap) file representing a normal scenario with no violations to the specified constraint and then we run it against the pcap file with anomalous packet data. Correct count of failed packets, generated by the constraint engine code for the latter pcap file conforms to its accuracy.

abstract: M.A.Sc.


title: SOLID-STATE 17O NMR STUDIES OF GLUCOSE AND DEVELOPMENT OF 17O NMR AS A NEW PROBE OF GLUCOSE METABOLISM IN HELA CANCER CELLS

contributor:
WU, GANG
Chemistry

subject: 17O NMR, SSNMR

abstract: This thesis reports on synthesis of site-specifically 17O-labeled glucose and related molecules and their solid-state 17O NMR characterization. The thesis also describes the development of 17O NMR as a new probe of glucose metabolism in HeLa cancer cells. In particular, a total of seven 17O-labeled glucose compounds were made via chemical synthesis: [1-17O]-D-glucose, [2-17O]-D-glucose, [3-17O]-D-glucose, [4-17O]-D-glucose, [5-17O]-D-glucose, [6-17O]-D-glucose, and [6-17O]-2-deoxy-D-glucose. In addition, [6-17O]-D-glucose-6-phosphate and [1,1,5-17O3]-glutamine were prepared through enzymatic reactions. Solid-state 17O NMR experiments were performed to determine 17O quadrupole coupling and chemical shift tensors in all seven glucose compounds. This is the first time that any carbohydrate molecule has been completely characterized by solid-state 17O NMR. This thesis demonstrates that [6-17O]-D-glucose and [1,1,5-17O3]-glutamine can be used as new tracers for monitoring glucose/glutamine metabolism in live cells. Effects of insulin, oxygen concentration, and glutamine concentration on the glycolysis process in live HeLa cancer cells were monitored by 17O NMR in real time. Finally, some preliminary results of 17O NMR studies of hexokinase-glucose complex are reported.

abstract: PhD


title: Search For Invisible Nucleon Decay in SNO+ With Improved Sensitivity

subject:
SNO+
nucleon decay

abstract: The water phase of the SNO+ (Sudbury Neutrino Observatory) experiment has completed after the collection of ~305 days of total livetime worth of data, divided into two main sets. The effective concentration of U-238 and Th-232 in the water was determined using in situ analysis to be, for the second set of data, gU/gH2O: (3.64 +/- 0.74_(stat) + 1.28_(syst) - 0.99_(syst) x 10^-15 and gTh/gH2O: (3.08 +/- 3.22_(stat) + 1.60_(syst) - 5.00_(syst) ) x 10^-16. The water data can also been used to search for ``invisible" modes of nucleon decay, and a previous SNO+ publication set world-leading limits on relevant nucleon and dinucleon decay modes except neutron and dineutron decay. This thesis presents a re-analysis of the ``invisible" neutron decay mode of that first set of data, which reoptimizes the fiducial volume and develops an improved treatment of the dominant energy systematic uncertainties. This leads to a world-leading lower limit on the ``invisible" neutron decay lifetime of 6.91 x 10^29 years. A sensitivity analysis shows that including the second set of data that has lower backgrounds is expected to yield a lower limit on the neutron decay lifetime of 1.57 x 10^30 years, further improving the result.

abstract: PhD


title: A Mesh Independent Approach for Multi-Joint Topology Optimization

contributor:
Kim, Il Yong
Mechanical and Materials Engineering

subject:
Topology Optimization
Design Optimization
Structural Optimization
Assembly Design
Multi-Material Design

abstract:
Topology optimization (TO) has been identified as a leading method to reduce weight in both component and assembly level design. Optimum loadpaths within a designable region are determined, providing non-intuitive designs that can result in significant weight savings while adhering to structural performance criteria. Multi-material topology optimization (MMTO) is a subset of TO, which extends the problem to consider material selection and material existence simultaneously. Multi-material solutions, therefore, represent an assembly where each section of dissimilar material is a different component. Conventional MMTO, however, assumes perfect joining between dissimilar materials, omitting joining. Therefore, a manual solution interpretation process is required to add joints to these solutions. Once joints are added, performance metrics (i.e. compliance and mass) are subject to change. Multi-joint topology optimization (MJTO) directly addresses this issue, adding joining within the optimization problem. Interfaces between dissimilar materials are modeled as joints, which can impact the substrate loadpath and material selection. Previously presented MJTO methodologies are restricted to uniform meshes, limiting the scope of problems which the method can be applied.

In this work, a novel interface detection methodology is presented, expanding the MJTO methodology to irregular, non-uniform mesh types. A revision to the previously presented analytical sensitivities is presented to consider the coupling between adjacent elements resulting from the convolution operation in the interface detection procedure. The revised MJTO methodology is demonstrated with a series of case studies employing both academic and industry level models. A comparison between multi-material solutions when considering joining is presented, displaying the benefit of using MJTO when generating advanced multi-material designs.

abstract: M.A.Sc.


title: Microaggression and the Consumption of Poverty: A community's resistance to invasive walking tours in Vancouver's Downtown Eastside

contributor:
Godlewska, Anne
Geography and Planning

subject:
Downtown Eastside
walking tours
microaggression
everyday resistance
microresistance

abstract: From 2014 to 2016, Jenn Potter ran a walking tour called Tours by Locals, leading hundreds of people through the poorest neighbourhood in Canada, Vancouver’s Downtown Eastside (DTES). This tour focused on what she described as social enterprises in the community and cost $185 per person. Though Potter ran this walking tour with the hope that it would lead to more understanding and compassion towards the neighbourhood and its residents, residents of the community and activists did not see it this way. In response to this tour, anti-gentrification activists held their own 'Yuppie Gazing Tour' down the streets of Vancouver yelling 'The Downtown Eastside isn't a safari, drive away in your Ferrari!' Though protests around Potter's walking tour led to its end, there are still an estimated 25 to 30 walking tours in the DTES today. Guides justify their presence in the DTES in various ways and treat tours as benign sources of education and entertainment for tour participants. Based on interviews with 13 walking tour guides and attendance in 13 walking tours in the DTES, this research argues that walking tours in the DTES are not benign and are, in fact, invasive poverty tours. Walking tours in the DTES contribute to a narrative that erases its residents' rights- based histories and continues a politics of dispossession and displacement. Poverty in the neighbourhood is both made a spectacle of and obscured during walking tours creating microaggressions against the DTES community. DTES residents are epistemically backgrounded– "both targeted and 'sub-merged,' both identifiable and indefensible...hidden in plain sight" (Dotson, 2017, p. 420). Community members are not bystanders or backdrops in this process. Through acts of microresistance and everyday resistance against walking tours, DTES residents make claims about their rights to the city. These forms of resistance presented against walking tours both nuance and challenge traditional understandings of how resistance is legitimized and preformed.

abstract: M.A.


title: “NÃO ÀS REMOÇÕES: PELO DIREITO À MORADIA”: EXAMINING THE FANTASMA(S) DE REMOÇÃO/GHOSTS OF EVICTION AND THE INSURGENCE OF NETWORKED FAVELA HOUSING ACTIVISM IN RIO DE JANEIRO

contributor:
Masuda, Jeffrey
Kinesiology and Health Studies

subject:
housing rights
Rio de Janeiro
favelas
grassroots activism
dispossession

abstract: Since the turn of the 21st century, favela communities have faced new and unprecedented challenges in the light of renewed eviction threats and displacement connected to real estate development and speculation. The right to remain has become ever more complex as favela communities wrestle with and against dispossession and the political contexts which underpin its making. Yet, favela grassroots resistance has also grown in complexity and capacity. This dissertation focuses on the various motivations, processes, and spatio-political dynamics through which grassroots housing resistance have been mobilized in response to the threat of dispossession. Through participant observation, informal conversations, and interviews, I utilize an ethnographic approach to advance three inter-related arguments. First, I argue while dispossession operates as a technique of subjection for the preservation of differentiated treatment towards favela residents, it simultaneously motivates residents to exercise unique forms of agency that reflect the situated politics of their impending dispossession. In the nexus of subjection and agency, dispossession is not only opposed and negotiated, but it is also embodied and performed as a form of resistance unto itself. Second, I argue that such acts of agency have taken flight through the coming together of wider network relationships between favela residents and differently-scaled supporters to address both on-the-ground, localized struggles and to advance a broader politics of insurgency around favela housing rights in the city. Third, I argue that a broader politics of insurgent mobilization has been made possible through the enrollment of grassroots favela resistance into the digital. Digital mobilizations serve not only as the basis for physical actualizations of on-the-ground resistance, but it is also a means to foster broader imaginations of alternative ways to remain in the city. Collectively, this dissertation highlights the diverse spatiopolitical dynamics of dispossession and the ways it serves to underpin the dynamic and creative formation of subaltern, grassroots housing resistance in Rio de Janeiro.

abstract: PhD


title: Bazin-Brecht-Straub

contributor: Film and Media (Screen Cultures and Curatorial Studies)

subject:
Marxism
Bertolt Brecht
Andre Bazin
film theory
Jean-Marie Straub

abstract: In the wake of the ‘post-political’ turn and the foreclosure of politics as a productive space of “contestation and agonistic engagement” (Wilson and Swynegedouw 6) in the neoliberal age, this project seeks to return to and refurbish the contributions of the German playwright and theorist Bertolt Brecht (1898-1956) to film theory, particularly as they were engaged with and put into practice by the critics of the Cahiers du Cinema and Screen in the aftermath of the events of May 1968. Resisting the “Brecht-fatigue” which accompanied the larger global “Marxism-fatigue” (qtd. in Kleber 8) in the postmodern period, I argue for the enduring relevance of maintaining fidelity to a ‘politics of form’ as advocated by these thinkers while also acknowledging the theoretical excesses of the period as they have been identified by Sylvia Harvey and Dana Polan, namely, the conflation of Brechtianism with a deconstruction of film language and an impenetrable and self-cannibalizing modernism which was at risk of losing its political relevance. However, in order to redeem the remarkable films of Jean-Marie Straub and Daniele Huillet at the core of this project, arguably the exemplars of ‘Brechtian cinema’ who are most often singled out as embodying this excess, I attempt to initiate a hermenutical shift in the reception of their films by examining their underexplored ‘Bazinian dimension’ and the profound influence of Andre Bazin’s thought on Straub. Focusing on his 2014 film, Kommunisten, I argue that the political dimension of its style resides in its taking a particular attitude towards reality and articulates, through the power of the image, certain facts about the contingency of our situation today to demonstrate that these conditions are neither natural nor eternal, but can be infinitely transformed.

abstract: M.A.


title: THE COVID CARNIVAL, ANIMAL CROSSING, AND THE POWER OF VIRTUAL INSTALLATIONS

rights: Attribution-NonCommercial-ShareAlike 3.0 United States

subject:
Animal Crossing
Virtual Installation
Coronavirus
COVID
COVID-19
Interactive Media
Video Game Studies
Pandemic Studies
Curatorial Studies
Cultural Studies
Installation Art
Digital Art
Digital Games
Art

abstract: The pandemic has casted shadows upon us all, but fortunately, there is the healing power of art. The COVID Carnival and its subcomponent screencap-illustrated story “The Monster of Nian” are the memorabilia of my own struggles under the pandemic, and also an experimental installation aiming to try out the innovative medium of social video game Animal Crossing. It is an exploration of virtual interactions of the mind, and a combative prescription against the isolating effects of the COVID-19 pandemic. The project embeds multi-layered metaphors in its expressions and reflections, as the symbolisms of a carnival, a temple fair, a night market, the Lunar New Year, and a fable story visually autocorrected by adorable anthropomorphic animal characters. Together, I welcome you to my virtual island, my COVID Carnival.

abstract: M.A.


title: Exploring Engineering Students' Interpretations of Success

contributor:
Strong, David S.
Mechanical and Materials Engineering

subject:
Success
Student Success
Engineering Education
Research Study

abstract:
This study used quantitative methods to explore Canadian undergraduate engineering students’ interpretations of their success. The amorphous term “student success” is used by students, educators, academics, engineering professionals, and institutions to represent a wide variety of outcomes. Educators, academics, and institutions commonly define student success in terms of academic achievement and retention rate. This definition of student success was not developed with input from students, nor does it necessarily represent the diversity of the Canadian undergraduate engineering population. The purpose of this study was to explore how students define their success, investigate differences between groups of students, and identify changes students could make to best reach their future goals. A 60-question survey instrument was designed and tested in a mixed-method pilot study with a sample of graduate engineering students. Based on analysis and feedback from the pilot study, the research methodology and questions were improved and validated, and then the revised study was offered to the undergraduate engineering students at Queen’s University with n = 266 responses, a response rate of 8%.
The results from the research suggest that students define their success in nuanced ways. Academic achievement and retention are commonly used by students to measure their success, but the importance of these criteria is low relative to vocational outcomes and personal happiness. The results of this study suggest an updated definition of “student success” for use in the academic environment: academic achievement; attainment of learning objectives; acquisition of desired skills, competencies, and practical experiences; wellbeing; persistence; and post-graduation performance. Demographic differences did not tend to have a large effect on the way students defined their success, which challenged previous findings in the literature. Students commonly suggested seeking additional practical experience as the best way to attain their future career goals.
This updated definition of student success better represents the interests of all stakeholders in the academic environment, including students, and provides valuable insight to the engineering education community. Educators can use the results of this research study as a resource and inspiration in teaching and mentoring students to achieve their own personal version of success.

abstract: M.A.Sc.


title: Determination of Fluorine Using Electrothermal Vaporization Coupled to Inductively Coupled Plasma Optical Emission Spectrometry

contributor:
Beauchemin, Diane
Chemistry

subject:
chemistry
fluorine
analytical chemistry
ETV
ICP

abstract:
Fluorine (F) can be found in many consumer products because of its diverse beneficial properties and high efficacy as a functional group or additive. With excessive chronic exposure, it can yield negative effects on an organism and thus must be monitored carefully. Due to its high ionization potential, F is considered as a difficult analyte to monitor and improvements for its detection are of interest. The work conducted in this thesis explored solid sampling electrothermal vaporization (ETV) coupled to inductively coupled plasma optical emission spectrometry (ICPOES) for the determination of F in plant-based materials.
 A method was developed for ETV-ICPOES to determine F in solid samples, where atomic emission of F was monitored. This technique eliminated time-consuming sample preparation procedures, like acid digestion, which would typically precede analysis for traditional methods. To extend the capability of ETV-ICPOES for F detection, standard solutions were explored for external calibration to eliminate the need for matrix-matched reference materials. This method allowed quick screening of F in both solid samples and standard solutions using ETV-ICPOES.
To improve the detection of F using ETV-ICPOES, an Ar-H2 mixed-gas ICP was investigated, where H2 was mixed with the Ar carrier gas through the ETV furnace. Comparing the method with and without H2, the addition of H2 degraded the sensitivity of F in solid samples. Despite a degradation in sensitivity, the detection limits were improved in solid samples, allowing more accurate detection of F with a mixed gas ICP. This method was not applicable to standard solutions, as it degraded both sensitivity and detection limits following H2 addition. Utilizing ETV-ICPOES, methods for the detection of F were investigated and developed, allowing for rapid determination in a variety of solid and liquid samples.

abstract: M.Sc.


title: Time Series Clustering Using Coherence

contributor:
Takahara, Glen
Burr, Wesley
Franczak, Brian
Mathematics and Statistics

subject:
Time series clustering
Spectral analysis
Spectrum
MSC

abstract: Time series clustering has drawn increasing attention with the rising popularity of machine learning and artificial intelligence. In this thesis, a new technique for clustering time series based on the coherence between time series in the frequency domain is proposed. Several comparisons between the proposed techniques and some classic clustering algorithms are performed using both simulated and real world data sets. To evaluate the cluster assignment accuracy, the  Adjusted Rand Index is used as the performance evaluation criterion. We find that under certain restrictive conditions, namely the classic ``signal in noise'' case, the proposed method performs very well compared to the classic $k$-means clustering algorithm and a variation that focuses on clustering extracted features of the data. Through extensive simulation studies, we  also present cases where the proposed methods perform poorly. The thesis concludes with a discussion of some ideas for future work in this area.

abstract: M.Sc.


title: Colder Now: Surveillance as Contemporary Colonialism in Canada

contributor:
Murakami Wood, David
Cahill, Susan
Cultural Studies

subject: surveillance; colonialism; settler; whiteness; research-creation; art; policing; performance

abstract: Canada is a settler state built on systemic racism, and is maintained by systems of contemporary colonialism. Systems of contemporary colonization such as internal colonialism (Tuck and Yang, 2012) take the form of the surveillance and policing of Black, Indigenous, and People of Colour. Through a white settler artist-scholar lens, this research exposes instances of surveillance and policing in Canada, by analyzing policies such as the “Anti-terrorism Act, 2015” (Bill C-51) and its effect on non-white citizens. This portfolio of essays and visual work draws knowledges from my experience as a white settler artist-scholar. I use research-creation as a methodology for situating myself in this narrative, while complicating my identity through self-reflexivity. I critically engage with and attempt to disrupt the systems that continue to privilege me because of my white settler identity. More importantly, I see my creative practice as a method of decolonizing surveillance studies, while also rethinking and unsettling surveillance as not only a practice or system, but a political identity tied to whiteness and white settlerhood. Surveillance and policing is more than a way of governing and controlling citizens, but of creating citizens. Through an analysis of function creep, public policy, and law, I theorize surveillance as a political identity and a producer of knowledge in its own right, through visual and performative means.

abstract: PhD


title: A DATA BASED STUDY OF ASPECTS OF THE GEOMETRY AND MECHANICS OF MEANDERING STREAMS

contributor:
da Silva, Ana Maria
Civil Engineering

subject: meander wavelength, resistance to flow, cross-circulatory motion, convergence-divergence zones

abstract:
The present study explores aspects of the geometry and mechanics of meandering streams based on a significant dataset consisting of laboratory and field observations.
The work focuses on three main issues that, despite systematic research on the topic, remain poorly understood. The first aspect examined is the relationship between meander wavelength and the flow width B. A dimensional analysis of the phenomenon indicates that there is a proportionality factor in this relationship which is a function of h/D and B/h. On this basis, a new empirical equation introduced.
The second issue studied was the performance of different methods to quantify the effect of bends on the resistance to flow in real meandering. The analysis conducted in this work included the methods by Rozovskii (1957), the Soil Conservation Service (SCS) (1963), Chang (1983), the linearized SCS (LSCS) by James and Wark (1992), James and Wark (1992), and Ervine and Ellis (1987). The main difficulty in evaluating the methods was the uncertainty on the selection of the original value of the resistance factor (n, c, f). In this work, this was selected by the author so as to produce the best overall results. The methods by Rozovskii (1957) and Chang (1983), which have a theoretical foundation, were found to best capture the additional losses due to bends. However, due to the uncertainty on the selection of the original value of n, it is not possible to assert how close, or how far, they are from reality.
The third issue addressed in this work relates to the cross-circulatory motion in meandering rivers and its intensity depending on the values of width-to depth ratio B/h. Four laboratory tests involving the tracking of the paths of particles transported as bed load as well as flow velocity measurements, were conducted to gain insight into the threshold value of B/h beyond which cross-circulatory motion becomes of secondary importance where the bed deformation is concerned. It was demonstrated the decrease of the intensity of the cross-circulation with the increase of B/h, Factual evidence that bed material is transported downstream without crossing from the outer to the inner bank.

abstract: PhD


title: Characterization of Molecular Partners of the Programmed Death (PD)-1/Programmed Death Ligand (PD-L)1 Immune Checkpoint

contributor:
Graham, Charles
Biomedical and Molecular Sciences

subject: PD-1

subject: PD-L1

subject: CD274

subject: BioID

subject: BirA*

subject: interacting partners

subject: cytoplasmic interacting partners

subject: cytoplasmic interacting partners of PD-L1

subject: intracellular

subject: PD-L1 interacting partners

subject: PD-L1 binding partners

subject: Immune checkpoint

subject: PD-1/PD-L1

subject: PD-1/PD-L1 immune checkpoint

subject: reverse signalling

subject: reverse signaling

subject: PD-L1 reverse signalling

subject: PD-L1 reverse signaling

subject: cancer

subject: tumour

subject: tumor

subject: bi-directional

abstract: Since its discovery, the Programmed Death (PD)-1/Programmed Death-Ligand (PD-L)1 immune checkpoint has been an area of interest in cancer research due to its role in conferring immune escape to tumour cells. Most research on the PD-1/PD-L1 receptor signalling axis in tumour progression is centered around inactivation of immune effector phenotypes. However, we have recently demonstrated bi-directionality of PD-1/PD-L1 signalling resulting in acquisition of drug resistance and metastasis-promoting phenotypes in tumour cells. Thus, we hypothesized that PD-1-induced PD-L1 signalling in tumour cells results in cytoplasmic PD-L1-protein interactions which are linked to the acquisition of malignant properties. To uncover interacting partners of the cytoplasmic tail of PD-L1, an in vivo biotinylation technique called BioID wherein BirA* (R118G), a promiscuous form of the prokaryotic biotin ligase (BirA), ligated to the cytoplasmic region of PD-L1 was used. Cells were treated with recombinant PD-1 to activate BirA*-PD-L1 and incubated with biotin. Controls consisted of cells incubated in the absence of PD-1, as well as of cells transfected with the BirA* construct without PD-L1. Biotinylated proteins were isolated via streptavidin binding affinity. Nanostring® Analysis was also performed to provide exploratory information on differential mRNA expression. We provide evidence that our BirA*-PD-L1 transgene product is functional and found that PD-L1-cytoplasmic protein interactions occurred more often upon PD-L1 stimulation with recombinant PD-1. This supports our hypothesis that cytoplasmic interacting proteins facilitate PD-L1 intratumoural signalling. Results of this research may help lead to the identification of druggable targets as alternatives or adjuvants to immune checkpoint blockers as novel anti-cancer therapeutics.

abstract: M.Sc.


title: Optimization of Luminescent Metal-Organic Compounds for Oxygen Sensing Applications

contributor:
Wang, Suning
Kozin, Igor
Stamplecoskie, Kevin
Chemistry

subject:
oxygen sensing
luminescent materials

abstract: Oxygen sensing devices are valuable to several fields for medical, environmental, and pressure-sensing applications. Recent developments to optic fiber and waveguide technology have made luminescence-based molecular sensors more competitive than traditional sensing methods due to their easy modes of detection and portability. Several transition metal complexes have been investigated for their use as luminescent probes for the detection of molecular oxygen. Through studies that investigated their effectiveness in several different polymer matrices including polydimethylsiloxane (PDMS) and poly-(1-trimethylsilyl)-propyne (PTMSP), it was determined that compounds immobilized in PDMS were more stable while compounds immobilized in PTMSP were more sensitive. A more homogeneous dispersion was found to be achieved in PDMS compared to PTMSP, paving a path for potential sensing applications. This work provides the basis of a promising design of more robust oxygen sensors based on the incorporation of a more rigid ligand frame to stabilize metal complexes.

abstract: M.Sc.


title: DNA Polymerization in Microgravity and the Future of Human Space Travel

contributor:
Virginia, Walker
Biology

subject:
Microgravity
DNA repair
DNA polymerases
DNA Sequencing
Space
Radiation
Parabolic flight
Polymerase fidelity
Synthetic biology
Biosensors
Biostasis

abstract:
The coming decades will represent a quantum leap in the field of crewed space travel, with planned missions back to the Moon, forward to Mars, and possibly beyond. The substantial biological threats of long-term space exploration are still key barriers to enacting these goals. Microgravity and radiation encountered in space are cellular stressors that could severely compromise the health of future astronauts leaving earth’s orbit. Of specific concern is the impact of these stresses on DNA. The Polymerase Error Rate in Space (PolERIS) experiment was devised to identify whether DNA polymerase enzymes, essential for both replication and repair of the genome, are more prone to errors in microgravity. This research necessitated the development of both novel genetics and engineering-based approaches to conduct experiments in microgravityaboard a parabolic flight plane. It was determined that Klenow fragment (exo+), an E. coli DNA polymerase I derivative with a 3’→5’ exonuclease proofreading domain, was 1.1-fold more prone to both substitution (p = 0.02) and deletion (p = 1.51E-7) errors in microgravity when compared to earth-like gravity. This effect was more pronounced in Klenow fragment (exo-), which does not posess proofreading capability, where substitutions and deletions respectively occurred 2.6-fold (p = 1.98E-11) and 1.5-fold (p = 8.74E-13 ) more frequently in microgravity than earthlike gravity.
In addition to ensuring genomic protection in space, the ability for cells to remain viable on long-term space missions may require innovative solutions, such as inducing cellular biostasis for both preservation of cellular isolates and possibly humans in the far future. The Biostasis project of the Defense Advanced Research Projects Agency, USA requires a comprehensive set of assays to quantify various modes of DNA damage potentially incurred during cellular stasis. A research exchange program facilitated early-stage efforts  to develop DNA repair pathway-specific cell-based fluorescent biosensors. Thus, together with the PolERIS experiment, this thesis contributes to our current understanding of how polymerases exhibit altered functionality in microgravity, and strategies to detect specific modes of DNA damage with novel cell-based biosensors.

abstract: M.Sc.


title: Impact of Chest Wall Restriction on Cardiac Output and Exercising Muscle Oxygenation

contributor:
Tschakovsky, Michael E
Kinesiology and Health Studies

subject:
chest wall restriction
cardiac output
sympathetic vasoconstriction
muscle oxygenation
mean arterial pressure regulation
blood flow

abstract: Restrictive pulmonary diseases (RPD) encompass diseases whereby the lungs are prevented from being able to fully expand. One way that these diseases can manifest is through increased chest wall stiffness. A common symptom that presents in individuals with RPD is reduced exercise capacity. This is commonly thought to be due to reduced ventilation and increased sensations of breathlessness. Chest wall restriction (CWR) is a strategy that mimics RPD by constricting the chest wall. A subsequent result of CWR is that it decreases the amount of blood that is pumped by the heart (cardiac output, CO). When CO is limited, it is possible that the amount of blood being delivered to the exercising muscles may also be reduced, which would have an adverse effect on exercise tolerance. Whether exercising muscle blood flow is affected by a limitation to CO in submaximal exercise is unclear, and therefore the effects of CWR on muscle oxygenation are unknown. As CWR mimics RPD, the CO response to exercise may also be blunted in these individuals. This could lower blood flow to the exercising muscle and be an additional mechanism by which exercise capacity is lowered in RPD. Therefore, we tested whether exercising muscle oxygenation is lowered by a CWR-mediated blunting of CO. Twelve individuals completed exercise cycling tests under normal and CWR conditions. When CWR was applied, exercising CO was lower than what was seen under normal conditions. When CWR was removed during exercise, CO was restored to control levels. In addition, the removal of CWR resulted in an improvement to exercising muscle oxygenation, while no change was seen under control conditions. We interpreted these findings to be consistent with lowered muscle oxygenation with CWR due to a reduced CO, indicating that blood flow to the muscle was reduced. Furthermore, there is potential for this mechanism to exist in individuals with RPD, contributing to their experienced exercise intolerance. However, this remains to be tested.

abstract: M.Sc.


title: HYBRID ENERGY STORAGE SYSTEMS FOR ENERGY EFFICIENT ELECTRIC DRIVE VEHICLES: CONVENTIONAL APPROACHES AND MUTLI-SOURCE TOPOLOGIES

contributor:
Hashtrudi Zaad, Keyvan
Bakhshai, Alireza
Praveen, Jain
Electrical and Computer Engineering

subject: Batteries, SuperCapacitors, Multi Source Inverters, Hybrid Energy Storage systems,

abstract: With the increasing global awareness and call for reduced dependence on fossil fuels and their polluting byproducts, energy efficient electric vehicles are gaining more attention for replacing internal combustion engine vehicles. Current battery technologies such as the Li-ion batteries, as the main source of energy in the electrified vehicles offer good energy density features, which fulfills the energy requirements for covering long mileages. However, other performance metrics for batteries such as power density, thermal operating range, and cyclic life span is not sufficiently high. In this regard, electric vehicle manufacturers have been overdesigning the battery packs in their products to offer adequate degree of confidence to the market for more appeal towards the electrified vehicles. This has led to an increase in the weight, volume, and the price of the battery packs. As an attempt to address the aforementioned challenges, hybridization of the battery packs with super-capacitors has been suggested. Super-capacitors offer complementary characteristics to the battery packs such as high-power density, wide thermal operating range, and high number of cyclic life span. Nevertheless, hybridization of the battery packs as the energy source and the super capacitors banks as the power source to take the advantages of both sources introduces new challenges. The need for electrical converters for compliance of these sources, and the requirement for the control system to share the power demand between these two sources based on their inherent features are among the concerns to be addressed.  This thesis introduces new electronic hardware structure for incorporative utilization of battery packs and super-capacitor banks, moderated by supervisory control systems for power sharing purposes between the energy and the power sources in electric vehicle applications.

abstract: PhD


title: Hydrological and Hydrochemical Responses From Thawing Permafrost in the Canadian Arctic

contributor:
Lafrenière, Melissa
Lamoureux, Scott
Geography and Planning

subject:
Arctic
permafrost
climate change
hydrology

abstract:
The objectives of this research are to better understand: (1) how Arctic watersheds respond in terms of hydrological processes to deepening active layers, (2) what the short and long-term changes are to surface water chemistry in watersheds impacted by thermal and physical permafrost disturbances, (3) which key factors control permafrost chemistry and runoff solute loads, and (4) where in the Canadian Arctic are changes to surface water chemistry expected to be the most pronounced with continued climate warming.

During exceptionally warm and wet summers, deep ground thaw enhances the infiltration and storage of rainfall and has the potential to solubilize inorganic ions previously stored at depth in the transient layer. Subsequent mid to late- summer rainfalls act as a hydrological flushing mechanism, mobilizing solutes from the subsurface thus substantially increasing ion concentrations in surface runoff. Exposure and mobilization of soluble ions in near surface soil because of physical permafrost disturbance is shown to be a key control over dissolved ion concentrations. Runoff in a disturbed catchment showed increased total dissolved solute (TDS) concentrations and seasonal TDS fluxes, and changes to the relative composition of individual ions in an undisturbed catchment. Impacts in the disturbed watershed persisted for the seven years after disturbance, consistent thaw of the solute-rich transient layer and upper permafrost. Thermal perturbation increased TDS concentrations and seasonal fluxes in runoff for up to two years as ions released from ground thaw were available for flushing in subsequent summers. Bulk ion concentrations in near-surface ground ice differ across the Canadian Arctic by several orders of magnitude. Regional differences in bulk ionic concentrations in transient layer and near-surface permafrost ground ice are controlled by geomorphic factors such as elevation, surficial geology and landscape history. Highly localized factors that control drainage (e.g., ground ice content and soil texture) appear to influence the solute storage patterns in ground ice. Low elevation coastal areas may be more at risk to water quality impacts from permafrost degradation compared to higher elevation, inland areas. Contributions from this research are critical for anticipating changes to water quality, aquatic systems, community water supplies and land-ocean transfers in the Canadian Arctic.

abstract: PhD


title: THE ANALYSIS OF SAMPLES WITH COMPLEX MATRICES FOR ELEMENTAL CONCENTRATION

subject:
ETV
Nutraceutical
Sea Cucumbers
Solid Sampling Analysis
Platinum
ICP
Chemistry
Analytical Chemistry

abstract: Exposing organisms to elements can lead to varied effects. In the foodstuff and pharmaceutical industry, elemental exposures are often present in the form of contamination and must be monitored for public safety due to the potential toxic effects they can have upon consumers. The following work shows a method to rapidly analyze foodstuffs and medications for elements of interest through the use of an electrothermal vaporization (ETV) introduction system paired with inductively coupled plasma (ICP) optical emission spectrometry (OES). This technique circumvents many of the traditional problems associated with measuring certain elements such as length and complexity of analysis along with the requirement that solid samples must be dissolved pre-analysis. This technique also allows for the direct analysis of solids, liquids and slurries, and enables the selective determination of these elements and their subsequent measurements in a variety of matrices. Another avenue where elemental concentration is a field of interest is in biological systems and food webs. Through exposure to varied anthropogenic sources, many animals are at risk of elemental contamination and the resulting toxicity. Marine species are particularly vulnerable to this phenomenon due to the propensity of accumulation of many elements in waterways and bodies of water. This research extracts the element of interest, As, from sea cucumbers (SC) through a sequential extraction in order to determine its concentration via ICPMS (mass spectrometry). A high-performance liquid chromatography system was also paired with ICPMS to allow for speciation of the various As species present within the SCs. In the field of medicine, elements are used as functional groups or centers in molecules based on their respective reactivity or propensity to accomplish particular effects on an organism. In chemotherapy, researchers have effectively used Pt containing compounds to treat cancerous growths. To monitor the absorption of Pt in human cells, this research utilizes ETV-ICPOES to directly analyze these cells without the need for acid digestion or cell pre-treatment. Through utilizing unconventional sample introduction techniques and sample pre-treatment, many problems that plague traditional measurement of these elements in varying matrices can be circumvented.

abstract: M.Sc.


title: Vision-aided Inertial System for Near-real-time Positioning and Navigation of Unmanned Ground Survey Vehicles in GNSS-denied Environments

contributor: Geological Sciences and Geological Engineering

subject:
Inertial Navigation
Visual Odometry
GNSS-denied Navigation
Indirect Kalman Filter
Sensor Fusion

abstract: Positioning and navigation of unmanned ground vehicles (UGVs) in GNSS-denied environments is crucial to geological surveys required for subterranean and extraterrestrial exploration and mapping. While GNSS is the most accurate and reliable source of positioning service when operating in open sky environments, many field sites of geological interest for exploration and mining cannot receive GNSS signals. The use of robotic platforms helped improve data resolution and data collection speed compared to previous survey methods. The technological advances and the low cost of micro-electro-mechanical system (MEMS)-based inertial sensors (accelerometers and gyroscopes) enabled their use in positioning and navigation for many years. However, during prolonged surveys, the inertial-based positioning solution may become prone to rapid drift resulting in substantial position errors. This research explores integrating MEMS-based inertial sensors with a vision-based navigation system. The work completed in this thesis proposes a new method for aiding the inertial-based navigation solution with the vision-based navigation solution. Each of the subsystems is modified in order to optimize the navigation solution. The vision-based navigation relies on a visual odometry pipeline modified to replace the feature matching step with Lucas-Kanade optical flow. Simultaneously, the inertial-based subsystem is derived from the three-dimensional reduced inertial sensor system (3D-RISS), modified for a body-centred update. A unique body-centred approach relying on projecting position increments through time is used to minimize the errors previously occurring due to the correlation of position increment and heading angle. The fusion of both systems is based on a Kalman filter to estimate the position, heading and inertial sensor errors. The developed method was tested using a Husky A200 UGV. The field tests utilized the Robotic Operating System (ROS) for recording data from sensors and synchronization. The test trajectories were performed indoors at the Royal Military College of Canada in Kingston, Ontario and in the Brockville Railway Tunnel in Brockville, Ontario. This thesis presents illuminating findings of aiding a body-centred inertial system with only reliable vision updates, resulting in a reliable positioning and navigation solution operating for an extended duration in GNSS-denied environments.

abstract: M.A.Sc.


title: Investigating bacterial adhesion proteins as tools for controlling bacteria-surface interactions

contributor:
Davies, Peter
Biomedical and Molecular Sciences

subject:
RTX Adhesin
Bacteria-surface interactions

abstract:
Adhesins are cell-surface proteins that initiate target binding and surface colonization by bacteria on the
path to infection and biofilm formation. A deeper understanding of the interactions between adhesins and
their ligands may lead to the development of strategies for controlling infection and biofilm formation.
Using two ligand-binding domains from a model Repeats-in-toxin (RTX) adhesin in the Gram-negative
marine bacterium Marinomonas primoryensis, I was able to prevent their binding to a photosynthetic
diatom with which the bacteria form symbiotic biofilms underneath sea ice. The sugar-binding domain
was optimally blocked with the monosaccharide fucose, and the peptide-binding domain was efficiently
blocked with a peptide that ended in -Tyr-Thr-Asp. Homologs of these two ligand-binding domains are
widespread in Gram-negative bacteria, including many pathogens. The same approach was employed to
block the highly similar peptide-binding domain of FrhA adhesin of the pathogenic bacterium Vibrio
cholerae from binding to the diatoms.
Two adhesin engineering systems were explored as ways of altering the targeting of bacterial
colonization. In one, redesigned and shortened versions of the M. primoryensis ice- and diatom-binding
adhesin were tested for expression in Escherichia coli. In particular, the number of extender domains was
reduced from 120 in the wild type to 15 or fewer. Although there was no evidence of ice-binding domain
expression, antibodies to the extender domain and the diatom-binding domains detected these proteins on
the outside of intact cells. A set of novel adhesins based on the beta-intimin system were designed using
protein engineering techniques. In this series, a bacterial cellulose-binding module, and the peptide-binding domain of the M. primoryensis ice- and diatom-binding adhesin were separately fused to the end
of the beta-intimin adhesin. In neither case was there any sign of external presentation of the binding
domain. I suggest that these domains might have folded prior to passage through the adhesin pore, thus
blocking export.

abstract: M.Sc.


title: Laying Foundations for a Nanophotonics Research Centre and an Emergency Communications Network

contributor: Physics, Engineering Physics and Astronomy

subject:
Photonics
Telecommunications
Nanophotonics
Laboratory Design

abstract:
An interdisciplinary collaboration at Queen's is aiming to advance the frontiers of nanophotonics through shared equipment that will be introduced to the new Nanophotonics Research Centre (NanoRC), enabling picometer- and picosecond-scale observations with light intensities as low as a single photon. Notwithstanding, this requires instruments with high powers (over megawatts of peak optical power) and large footprints (up to multiple square meters). The designs described here interface light sources, spectroscopy, and metrology equipment for this facility. Physical constraints require that equipment be deployed (1) in stations sometimes separated by >50 m and (2) in a flexible manner, so that multiple users sharing some equipment can run dissimilar experiments in parallel.

Though my original intention was to design, integrate, and complete the first experiments with components specific to the NanoRC, the pandemic shutdown shifted my research direction: I led the launch of timing electronics in the facility, and, with James Godfrey, performed experiments to lay preliminary steps for progress in quantum optics at the NanoRC. At the time of writing, however, important components like single-photon detectors, light sources, and a triple grating spectrometer are on order or are awaiting purchase.  Nevertheless, this facility under construction involves many experimental research questions that need consideration. This thesis explores these design questions with an eye to supporting the overall research effort and providing a reference for future experiments.

Some of these experiments will involve materials and infrastructure intended for future telecommunications networks. To understand this field, I pursued an internship at Telecom Metric, a local startup, where I aimed to understand the broader context in which these materials would be used. I provided some design options for telecommunications networks to be used to efficiently and accurately route emergency calls to the closest responders. While this work did not reconcile quantum optics with telecommunications, it provided a glimpse into the very `applied' world of telecommunications, where secure single-photon communication and rapid switches based on novel materials have promising futures.

abstract: M.A.Sc.


title: Numerical Modelling of Wind-driven Hydrodynamics in Shallow Wastewater Ponds and Coastal Estuaries

contributor:
Mulligan, Ryan
Filion, Yves
da Silva, Ana Maria
Civil Engineering

subject:
Wastewater Stabilization Ponds
Delft3D
Numerical modelling
Field observations
Wind-induced mixing
Baffles
Temperature stratification
Coastal oceanography
Tropical Cyclones
Surface waves
Storm surge
Coastal Forecasting

abstract:
Throughout the world, shallow water (<5 m) environments, including ponds and estuaries, provide vital contributions to regional economies and environments. Despite their prevalence and importance, questions remain about the complex hydrodynamic processes that occur in these environments. In this thesis, two field sites, characterized by shallow depths and generally bounded by shorelines, are studied using observations and numerical modelling to improve understanding of hydrodynamics that occur in: a waste stabilization pond (WSP) in Ontario, Canada, and a back-barrier estuary in North Carolina, USA.

WSPs are applied for wastewater treatment throughout the world. Typically, they are designed using simplified equations that may not incorporate complex hydrodynamics, and existing numerical models have lacked validation. To address this, field monitoring of water levels, current, and temperatures was used to validate a high-resolution three-dimensional Delft3D model. Hydrodynamics were primarily wind-driven, with smaller contributions from outflows, and circulation patterns were classified into four hydraulic regimes. Vertical temperature differences of up to 8.0°C over the 1.7 m depth between the surface and bed were observed during an 8-month monitoring period, inhibiting mixing through thermal stratification. Using a simulated tracer, the hydraulic retention time was ~22% shorter than predicted by design equations. A dimensionless empirical equation was developed relating the longitudinal current to wind speed, direction, and outflows, which represents an important step toward incorporating hydraulic complexity into design.

During extreme storms, wind-driven changes in water levels and intense precipitation can contribute to flooding, particularly on low-lying coastal plains. To investigate the roles of rainfall and wind-driven storm surge on coastal flooding, two major 2016 storms, Tropical Storm Hermine and Hurricane Matthew were simulated using a coupled flow-wave model (Delft3D-SWAN). Results showed that different wind field inputs produced variations in coastal conditions, and that precipitation on the water surface inundated a larger area. This model was extended into a real-time forecast system, which provided generally accurate 36-hour forecasts during Hurricane Dorian, a major storm event that impacted coastal North Carolina in 2019. Collectively, these results emphasize the contributions of different processes to circulation and water levels, and provide guidance on atmospheric forcing impacts in back-barrier environments.

abstract: PhD


title: Three Essays in Corporate Finance

contributor:
Purda, Lynnette
Business

rights: Attribution-ShareAlike 3.0 United States

subject: Corporate finance, cost of equity, bonds, innovation

abstract: In this thesis I present three essays on Corporate Finance. Chapter 1 provides an introduction to the thesis, Chapter 2 presents “Cash Flow Volatility, The Opportunity Cost of Missed Investments, and the Financial Crisis.” This paper examines how firms changed their cash holdings in response to the 2008 financial crisis. I find that firms that would be expected to lose more borrowing capacity, and those that have more to lose from missed investment opportunities increased their cash holdings the most. Chapter 3 presents “The Role of Equity Risk in Determining Share Price around Covenant Violations”, which examines the effect of covenant violations on equity risk. I find that firms see a significant increase in estimated cost of equity in the year leading up to a covenant violation, and a significant decrease in the estimated cost of equity in the year following a covenant violation, and that this change in equity risk contributes significantly to well-documented changes in share price around a covenant violation. Chapter 4 presents “Classifying Innovation: The Influence of Process vs Product Patents on Firm Profitability”, which proposes a new textual analysis method of classifying pharmaceutical patents as process or product innovations, and uses the time series data this technique generates to demonstrate the novel result that the effects of current innovative activity on firm profitability is heavily mediated by a firm’s past innovation choices. Chapter 5 concludes the thesis.

abstract: PhD


title: Assessing the uncertainties of Radar and LiDAR derived digital elevation information over static and dynamic terrain

subject:
SAR
LiDAR
DEM
POCS
sand dunes
DSM
elevation
elevation change

abstract: The satellite era brought the advantages of obtaining fast, reliable, and repeated measurements over time on a global scale. Digital Elevation Information is a necessity for any scientific and engineering project that involves terrain, urban planning, and monitoring of natural hazards. The accuracy of Digital Elevation Information is influenced by systematic errors which may be caused by the instruments, the effects of climate on some sensors and regional dynamic processes. The repeatability of measurements collected by satellite sensors introduces time as a new dimension and a new source of uncertainty. In this study, the uncertainties of Synthetic Aperture Radar and Light Detection And Ranging derived products are assessed in static and dynamic terrain cases. A synthetic aperture radar derived digital elevation model is validated over an urban area using airborne LiDAR, for which the side-looking nature of synthetic aperture radar and the variations in wavelength depending on penetration depth are observed as the principal factors influencing uncertainty over built and vegetated environments. Sand dune migration is studied using satellite laser altimetry. By using the phase of the elevation profiles and applying a cross-correlation between overlapping profiles, we estimate migration vectors resulting in a database that can be correlated with the region’s wind patterns to locate the effects of extreme events such as sand or dust storms. Cloud cover, among other factors, interferes with the altimetry signal causing data losses. To fill these gaps, Projection onto Convex Sets is employed to interpolate between known elevation locations using the known properties of the elevation profiles in the region. Understanding these dynamic processes from satellite observations allows us to address long-term and short-term sand dune migration hazards and develop mitigation strategies.

abstract: M.A.Sc.


title: MONITORING GROUNDWATER DYNAMICS WITH TIME-LAPSE GRAVITY GRADIOMETRY

subject: Geophysics, Time-Lapse Gravity Gradiometry, Forward modelling, Inversion modelling

abstract:
This thesis presents the feasibility of monitoring the depletion and recharge of ground and surface water reservoirs using gravimetry. This is an important exercise because many industrial processes are water-intensive, and therefore the use of sustainable and proximate water resources is preferred.

Gravity and gravity gradient signals are forward modeled to estimate signal strength, as well as the spatio-temporal distribution of water reservoir dynamics. The required sensitivity of the gravimeters, the time intervals between measurements, and the number and density of gravity stations are evaluated. Time-lapse gravimetry for small-scale reservoirs poses two discernible obstacles: i) a microgal sensitivity requirement, and ii) noise from environmental or anthropogenic sources in the vicinity of the reservoir. In principle, the use of two gravimeters in tandem could compensate for environmental noise and improve the gravity gradient measurements. The examples of reservoir models presented in this thesis display the resolvability of groundwater dynamics from surface gravity gradiometry.

Inversion modelling is used to incorporate gravity and gravity signals. Inversion modelling poses an optimization problem, known as non-uniqueness, where there are many potential solutions that could fit the observations. The gravity signals constrain the inversion and are able to map out higher and lower density regions. The results of inversion modelling indicate that inversion modelling can provide useful information about the drawdown caused by water extraction or injection processes.

The resolvability of drawdown variability across a reservoir using gravity gradiometry is tested varying two main parameters: survey grid sampling and well pair separation as a proxy for spatial resolution. The results of altering these two parameters indicate that survey grid sampling and well pair separation have an impact on the resolvability, but do not pose significant challenges for the survey design.

abstract: M.A.Sc.