VictorJuiz/thesis huggingface dataset:
Design and Optimization of Buoyant Photocatalysts for Passive Degradation of Trace Organic Pollutants in Drinking and Industrial Process-affected Water

The 1.6•10^12 L of oil sands process-affected water (OSPW) in sedimentation ponds in northern Alberta contains 20-120 mg L-1 of naphthenic acids (NAs), a class of molecules acutely toxic to aquatic life [1]. Photocatalytic degradation of NAs in OSPW has been demonstrated by TiO2 containing buoyant photocatalysts [2], [3]. Composed of a buoyant hollow glass microsphere, TiO2, and a silica binder, the buoyant photocatalyst degrades the NAs in a passive advanced oxidation process. However, nucleophilic attack on the silica binder by hydroxide ions of the alkaline OSPW reduce the durability of the buoyant photocatalyst. Formulation changes to the buoyant photocatalyst resulted in the adoption of alumina hydrosol as a more durable binder over the previously used silica. In a second study, the improved buoyant photocatalyst was then used to detoxify water containing trace amounts of 1,4-dioxane, an emerging and recalcitrant pollutant found in drinking water.

Keywords: 1
4-dioxane
Detoxification
OSPW
Remediation
TiO2
Advisor: Gu, Frank X
Liesegang Ring Formation from Periodic Precipitation of Molecules and Nanoparticles

Reaction-diffusion is a universal process that results in hierarchically organized structures, such as Liesegang rings. This process offers a strategy to develop materials with ordered morphologies. The generation of periodic precipitate patterns resulting from the synergy of transport and reactions of chemical components is limited to multicomponent systems of species on the same size scale, such as molecules or nanoparticles. Here, upon the evaporation of an aqueous suspension, chiral cellulose nanocrystals (CNCs) and L-(+)-tartaric acid (TA) resulted in periodically ordered rings of alternating CNCs and TA widths. The CNCs self-assembled with cholesteric order and showed characteristic circular dichroism properties, and TA packed in radially aligned bundles. The alternating bands propagated with a finite, constant velocity, and their widths could be controlled by film composition and ambient relative humidity. A kinetic model reproduced the experimental results. These results will have implications on the design strategies of optically active, highly ordered materials.

Advisor: Batey, Robery A
Measuring Gradients in Gaseous Elemental Mercury Using a Passive Air Sampler

Mercury (Hg) monitoring is necessary to constrain the global Hg cycle and to develop policies for reducing Hg emissions. Passive air samplers (PAS) are an accessible method for monitoring gaseous elemental mercury (GEM). I tested the suitability of PAS for recording GEM gradients at widely varying scales. Vertical gradients on the scale of centimeters to tens of meters measured over soil and within a forest allowed for the observation of GEM uptake in growing vegetation, the determination of the air-surface exchange direction, and the estimation of evaporative fluxes from contaminated soil. When PAS were deployed above a field with known soil contamination, slightly different spatial contamination patterns suggest horizontal GEM advection. on a continental scale, the PAS were also used to map annually averaged GEM levels across South and Central America. Accounting for the effect of wind speed on the PAS sampling rate is necessary to distinguish small concentration differences.

Keywords: Mercury
Passive air sampler
Sampling rate
Spatial gradients
Advisor: Wania, Frank
Clearing Up The Smoke: Clinical and Radiographic Characterization of a North American Cohort of Childhood Moyamoya

Moyamoya (MMA) is a progressive cerebral steno-occlusive angiopathy which can lead to strokes. Its natural history derives from adult East Asian cohorts with idiopathic disease. Clinical differences in pediatric, non-Asian and syndromic patients are reported but understudied. This study aimed to: 1) characterize clinical and radiographic features of a North American cohort of childhood moyamoya; 2) identify risk factors of ischemic event recurrence (IEC) and poor outcome; and 3) design an IEC predictive model. Idiopathic MMA presents with transient ischemic attacks (TIA) and bilateral disease and have a higher risk of IEC while the neurofibromatosis type 1-related syndromic form tends to be unilateral and indolent. A young age, infarcts, bilateral and advanced disease predict poor outcome. Significant angiographic posterior deep collaterals and lack of leptomeningeal collaterals predict poor outcome, but good revascularization response. Asian ancestry, TIA, ophthalmo-ethmoidal, leptomeningeal, and middle meningeal collaterals and steal phenomenon on functional MRI predict IEC.

Keywords: children
moyamoya
neuroimaging
stroke
Advisor: Dlamini, Nomazulu
A Deep Generative Model for Missing Data Imputation

Machine learning relies on data. However, real-world datasets are far from perfect. One of the biggest challenges in working with these datasets is missing data. In this work, we present a novel deep generative model for missing data imputation. What makes our method unique is the focus it puts on classification accuracy while it imputes missing data. This makes our model particularly useful for classification problems. We formulate our proposal as a sequential game and show that it learns the true data distribution. Furthermore, we propose a new algorithm for optimizing our objective. Our proposal is able to learn the feature importance and impute critical features more accurately. Experimental results show our method outperforms existing methods in terms of classification accuracy.

Keywords: Computer Networks
Deep Learning
GANs
Generative Models
Machine Learning
Missing Data
Advisor: Liang, Ben Prof
Probabilistic Methods for Crowd-sourced Indoor Localization

Despite its shortcomings, fingerprinting \textit{Received Signal Strength} (RSS) localization is still one of the most widely used methodologies for indoor localization. One of its shortcomings is due to its limited accuracy (around 3 meters). Based on empirical data, it is known that its limited accuracy is because of the data quality. This empirical data is however not justified by the currenct model of the RSS data. In this thesis a model is proposed for RSS signals which is in a better agreement with observations from the real data. By means of this model a lower bound is provided for localization error which explains the fact that this localization method can not attain sub-meter accuracies in practise. Aside from its limited localization accuracy, fingerprinting RSS localization has some practical challenges as well. A main challenge of RSS localization is its dependence on a high quality radio map. This makes RSS localization a labour intensive task as it requires technicians to collect RSS data on a regular basis to update the fingerprint database. In this thesis algorithms are proposed to reduce the sensitivity of localization algorithms to noisy data in radio map, making the use of crowd provided RSS, which are usually of less quality, feasible.

Keywords: Indoor Localization
Machine Learning
Noise Sensitive Regression
Advisor: Valaee, Shahrokh
Showing Off: Relocating Performance, Reclaiming Shame

By tracking my year of struggle and discovery as a theatre practitioner in the world of theatre scholars, this autoethnographic thesis investigates how my own theory of performance has come to be, and how early childhood trauma has fueled my practice. As a 58-year-old theatre practitioner, I have taken intellectual refuge in the Academy, which has emotional doors - the first and most significant being into a space of shame. Scholarship initiated this journey, beginning with Fred Moten and Stefano Harney's The Undercommons (2013), then finding its way into performance theology with Claire Maria Chambers Performance Apophatics (2017), and then finally queer theory with Maggie Nelson’s The Argonauts (2015) and the work of Eve Kosofsky Sedgwick. The thesis itself is a kind of performance that weaves through knowing into feeling by investigating my own work, my queerness, my journey through faith, and finally, my shame: its roots and its affect.

Keywords: Acting
Autoethnography
Memoir
Performance Studies
Queer Theory
Theatre
Advisor: Cesare Schotzko, Nikki
Preparation of Polyferrocenylsilane-b-Poly(oligo(ethylene glycol) methyl ether methacrylate) Rod-like Micelles for Biomedical Applications

Polyferrocenylsilane (PFS) diblock copolymers can form rod-like micelles by undergoing crystallization driven self-assembly (CDSA), enabled by the crystallization of the PFS core. For future studies in biomedical applications would require control over various physical aspects such as micelle length, morphology, and corona height. The formation of different micelles through CDSA is highly sensitive to initial conditions such as solvent concentration, aging temperature, unimer concentration, and polymer purity. In this pursuit, I investigated the synthesis and CDSA of polyferrocenylsilane-b-poly(oligo(ethylene glycol) methyl ether methacrylate) in different initial self-assembly conditions. I found that self-assembly with PFS30-b-POEGMA65 in 2-proponal with a 20 mg/mL unimer solution aged at room temperature performed the best compared to the alternatives explored.

Keywords: Drug delivery
Nanoparticle
Polymer
Synthesis
Advisor: Winnik, Mitchell A
PIV Study of Control by Synthetic Jets to Delay Flow Separation over an Airfoil

The effects of flow control by a synthetic-jet actuator with a high-aspect ratio slot on the low-speed flow around a NACA 0025 airfoil was investigated using Particle Image Velocimetry (PIV). Analysis was performed on phase-averaged PIV data of flow over the entire airfoil surface to visualize the role of jet structures in the delay of flow separation. When exciting the shear-layer instabilities of the flow, jet structures persisted near the boundary layer to 90% of the chord length while maintaining flow attachment. PIV experiments performed in a wind tunnel showed the creation and evolution of structures in the near-field of the synthetic jet. The structures induced by the synthetic jet advect as roller vortices for∼20 jet widths before instabilities cause transition to three-dimensional structures. Separation delay was achieved for control introduced behind the separation point. To improve the accuracy and resolution of PIV, the open-source program OpenPIV was modified.

Keywords: Aerodynamics
Flow Control
Flow Separation
Flow Visualization
Particle Image Velocimetry
Synthetic Jet Actuators
Advisor: Sullivan, Pierre E
The Effect of Food Access Interventions on Diabetes Outcomes: a Realist Review

People without secure access to food are more likely to have diabetes and diabetes is more prevalent among those with food insecurity. Studies of food access interventions aimed to improve diabetes outcomes have reported mixed results. We conducted a realist review to learn how different types of food access interventions operate in their given contexts to produce the observed diabetes outcomes. We developed candidate theories using information about the contexts, mechanisms, and outcomes of food access interventions collected from systematic reviews and tested and refined these theories with evidence from our systematic search of Ovid Medline, Embase and Cochrane CENTRAL. We found that both, interventions that provided food vouchers, and those that provided nutritionally appropriate food and diabetes education, reported reductions in participants’ hemoglobin A1c (HbA1c) levels, a common measure of blood sugar levels. The provision of medically tailored meals did not change HbA1c levels.

Advisor: Persaud, Nav
Mortality and Morbidity in Out-of-Hospital Deep Sedation and General Anaesthesia for Dentistry in British Columbia

The objective of this study was to determine the number of anaesthesia-related mortality and serious (permanent) morbidity events for dental treatment under deep sedation (DS) or general anaesthesia (GA) at out-of-hospital facilities in British Columbia. Mortality and serious morbidity events were identified by retrospectively searching the Chief Coroner of British Columbia database, College of Dental Surgeons of British Columbia database, and grey literature (Google News, Yahoo!, Bing) from 1984 to 2019. A survey of out-of-hospital DS/GA providers was conducted and used to estimate the number of DS/GA provided. No cases of anaesthesia- related serious morbidity were identified. Over the period of observation, 3 mortality events were identified. The estimated mortality rate was 2.94 per one million anaesthetics. This study suggests that the provision of out-of-hospital DS/GA for dental treatment in British Columbia has a low risk of mortality or serious morbidity.

Keywords: Ambulatory
Deep Sedation
Dentistry
General Anesthesia
Morbidity
Mortality
Advisor: Yarascavitch, Carilynne
Secure Aggregation in Federated Learning using Multiparty Homomorphic Encryption

We develop a method based on multiparty homomorphic encryption (MPHE) that enables the central node to compute the aggregate, while receiving only encrypted version of each individual gradients. We extend classical MPHE methods so that the decryption of the aggregate vector can be successful when only a subset of client nodes is available. This is accomplished by introducing a secret-sharing step during the setup phase. We develop conditions on the parameters of the MPHE scheme that guarantee correctness of decryption and (computational) security. We explain how our method can be extended to accommodate client nodes that do not participate during the setup phase. We also propose a compression scheme for gradient vectors at each client node that can be readily combined with our MPHE scheme and perform the associated convergence analysis. We discuss the advantages of our proposed scheme with other approaches based on secure multi-party computation.

Keywords: Federated Learning
Homomorphic Encryption
Secure Aggregation
Advisor: Khisti, Ashish
Divestment in Times of Change: The Loss of Major Donors in Art Galleries

The Sackler family is a billionaire American clan known for its major philanthropic contributions to the arts and culture sector around the world. Today they are perhaps best known for how they gained their fortune: primarily through the ownership of Purdue Pharma. Over the past decade, Purdue Pharma has come under fire for its production of OxyContin and allegations that it concealed data about the addictiveness of the drug. As a result, there have been protests against institutions that have accepted gifts from the Sackler family. Through discourse analysis of official institutional publications, media responses, and professional literature, this thesis tells the story of the tensions embedded in major gift philanthropy between an untouchable family and the institutions that walked away from them, and explores how an organization can best react when a donor’s money is found to be problematic.

Keywords: Fundraising
Management
Media
Philanthropy
Policy
Advisor: Luka, MaryElizabeth
Stanbridge, Alan
Inferring Dynamics of Short-term Synaptic Plasticity During Deep Brain Stimulation from Recorded Postsynaptic Responses

Parkinson’s disease (PD) is a debilitating neurological disorder that affects more than 6.2 million people globally. Although there is no proven stage-modifying treatment, several methods, including Deep Brain Stimulation (DBS), have been developed to control the symptoms of PD by delivering electrical stimulations into the subcortical regions. Despite successful outcomes of DBS, its underlying mechanism remained unknown. Recent experimental studies showed that DBS can induce short-term synaptic plasticity (STP) at the stimulation targets. However, to fully decipher the role of STP in the underlying mechanism of DBS, it is required to infer the dynamics of DBS-induced STP. In this thesis, I developed a new computational framework to study and an inference algorithm for the synaptic dynamics during DBS from intra- and extracellular recordings of the brain activities during DBS.

Keywords: Deep Brian Stimulation
Parkinson's Disease
Short-term synaptic plasticity
Advisor: Popovic, Milos MRP
Lankarany, Milad ML
A TX Clock Frequency Modulated Side-channel and a Time-modulated Phase Interpolator for High-speed Wireline Systems

This thesis focuses on two ideas in clocking systems that contribute to the reduction of power in high-speed wireline communication. The first project implements a side-channel to facilitate low-speed data transmission for transmitter-receiver co-optimization. The proposed side-channel modulates a transmitter clock’s frequency and uses the corresponding receiver's clock and data recovery to demodulate its clock-embedded data. A prototype side-channel was tested on a 7 nm 56 Gb/s PAM-4 transceiver with a 50 ppm frequency offset, and no visible impact on the high-speed link was observed. In the second project, a 14 GHz injection locked ring oscillator phase interpolator (PI) was designed using 16 nm FinFET technology. This PI time-modulates between four different injection points within a ring oscillator to generate 96 fine phase settings. Based on post-layout simulations, the proposed PI occupies an area of 0.0033 mm2, consumes 24.1 mW of power, and has a rms jitter of 592 fs.

Keywords: Clock and Data Recovery
Clocking Architectures
Frequency Modulation
Injection Locking
Phase Interpolator
Wireline Communications
Advisor: Chan Carusone, Anthony
Career Self-determination Theory and the Professional Immigrant Experience

Despite established international academic credentials and vocational experience, professional immigrants often face difficulty establishing careers in Canada. Immigration entails a myriad of psychological and financial stressors, including under- and unemployment. Career self-determination theory (CSDT) is an emerging metatheory that proposes considerations to enhance career development and vocational wellbeing. The purpose of the study is to develop a better understanding of the lived career experiences of professional immigrants to Canada while contributing to the development of CSDT. This exploration utilizes constructivist grounded theory in analyzing qualitative interviews with professional immigrants. Results reveal that the essential needs posed by CSDT, including career autonomy, career competence, and career relatedness, are reflected in the participant narratives. Participants demonstrated innate tendencies towards fulfillment of the essential needs, with fulfillment corresponding to greater vocational satisfaction. Theoretical and practical implications are discussed.

Keywords: Career Psychology
Career Self-Determination Theory
Career Transitions
Immigration
Retraining
Advisor: Chen, Charles P
Memory for Category Learning Experiences that Deviate From Established Knowledge

The formation and maintenance of conceptual knowledge allows people to organize their experiences and make predictions in novel situations. However, the ways in which people represent concepts internally is unclear. Inspired by a computational model, we asked whether specific category learning experiences are encoded in memory with more precision depending on how much they deviate from existing knowledge. Adults (N = 120) completed a category learning task followed by memory tests on events from learning. The results suggest memory is consistently precise for individual event elements but somewhat better for the associative links between higher deviation items and accompanying episodic details. In this thesis, I discuss possible explanations for these results, as well as avenues for future investigation. Broadly, these findings work towards validating a prominent computational model of category learning and in doing so, answering larger questions about how people build conceptual knowledge.

Keywords: Category Learning
Memory
Advisor: Schlichting, Meg
Cavity-nesting Bee and Wasp Diversity and Foraging Trip Duration in Urban Residential Gardens

Urbanization drives changes to biological communities; however, land cover heterogeneity may mitigate these impacts by providing a mosaic of resources. In my thesis, I evaluate patterns in solitary cavity-nesting bee and wasp communities in relation to land cover to determine how urbanization impacts diversity and resource foraging trip duration. Using nest boxes, cavity-nesting bees and wasps were sampled at 104 urban residential gardens. Bee and wasp richness, abundance, and diversity were analysed in response to land cover heterogeneity, proportion of green space and urban land cover. Bee and wasp diversity was negatively correlated with urban land cover, and for wasps, positively correlated with forest cover. Land cover heterogeneity was positively correlated with both bee and wasp abundance and richness. We further determined that cavity-nester foraging trips for nesting materials were significantly shorter than those for food provisions, but further work is needed to disentangle the effects of urbanization and heterogeneity.

Keywords: Cavity-nesting hymenoptera
Citizen science
Foraging efficiency
Land cover heterogeneity
Urbanization
Advisor: MacIvor, J. Scott
Incorporation of Fiber Bragg Grating Sensors in Additive Manufactured Acrylonitrile butadiene styrene for Strain Monitoring during Fatigue Loading

This study investigates the characteristics of Fiber Braggs Grating (FBG) sensors with respect to their feasibility for use in additive manufactured materials under fatigue loading. This was done through tensile fatigue testing of both standard Acrylonitrile butadiene styrene (ABS) specimens and ABS specimens containing FBG sensors. These sensors were incorporated into the material using two different techniques: inserting and embedding. Comparing fatigue test results between the specimen types showed that incorporating the FBGs into the material affected fatigue life differently depending on the load level, while also increasing the variation in fatigue life between specimens. The strain measurements of the embedded FBGs were seen to more closely resemble results from finite element simulations than were the measurements of the inserted FBGs, thus proving embedding to be the superior technique.

Keywords: 3D printing
Acrylonitrile butadiene styrene
additive manufacturing
Fatigue loading
Fiber Bragg Grating
strain monitoring
Advisor: Behdinan, Kamran
Microplastic Removal from Drinking Water Using Point-of-Use Devices

The occurrence of microplastics in drinking water systems has drawn increasing attention due to their ubiquity and unresolved implications regarding human health. Despite achieving high reduction efficiencies (70 to >90%) at conventional drinking water treatment plants (DWTPs), some microplastics remain (WHO, 2019). Since human consumption represents a small portion of total household water use, point‐of‐use (POU) water treatment devices may provide additional removal of microplastics (MPs) prior to consumption. The primary objective of this study was to evaluate the performance of commonly used pour-through POU devices, including those which utilize combinations of granular activated carbon (GAC), ion exchange (IX), and microfiltration (MF), with respect to MP removal. Treated drinking water was spiked with MPs typically reported in the literature (PET and PVC fragments, along with nylon fibers) at a concentration of 40±2.3 particles/L and representing a range of particle sizes (10-400 µm). Samples were collected from each POU device following 25, 50, 75, 100 and 125% of the manufacturer’s rated treatment capacity and subsequently analyzed to determine removal efficiency. The three POU devices examined effectively removed MP particles >10 µm, with mean removal efficiencies ranging from 71% to 100% upon attaining 125% of rated treatment capacity. Across two of the POU devices, removal was observed to improve over time which was hypothesized to be associated with a reduction in pore space. This study provides useful insight regarding the selection and operation of POU devices for consumers that seek this approach to reduce potential MP consumption.

Keywords: Drinking Water
Microplastics
Point-of-use devices
Water filtration
Water treatment
Advisor: Andrews, Robert C.