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Characterizing the Occurrence and Fate of Micropollutants in Aqueous and Environmental Samples: A Multidimensional Approach
No full textEmerging contaminants such as pharmaceuticals and per-and polyfluoroalkyl substances (PFAS) present persistent challenges for environmental monitoring due to their chemical diversity, trace-level occurrence and limited removal in conventional wastewater treatment. This thesis presents a dual approach combining experimental two-dimensional separations with computational modelling to advance contaminant detection and mechanistic understanding. A targeted liquid chromatography-mass spectrometry (LCxDMS-MS/MS) method was developed and applied to complex pharmaceutical mixtures, revealing improved compound differentiation and class-based clustering across orthogonal retention time and compensation voltage dimensions. These trends demonstrate the potential of LCxDMS-MS/MS as a selective, high-throughput workflow for micropollutant screening in aqueous matrices. Complementary to this, quantum chemical calculations were performed on PFAS molecules, specifically perfluorosulfonic acids (PFSAs), to elucidate degradation pathways and assess the influence of molecular conformation on fragmentation energetics. Calculations identified several concerted and non-concerted reaction pathways that contribute to product selectivity. Together, these efforts establish a framework that integrates instrumentation and theory to support more informed contaminant analysis and method development
Boundary Layer Transition on Airfoils and Wings in Unsteady Low-Reynolds Number Flows
No full textLaminar separation bubbles (LSBs) often form on wings and turbine blades that operate at aerodynamically low chord Reynolds numbers. Changes in the oncoming velocity magnitude, direction, and disturbance amplitudes may cause bursting of the LSB and a severe reduction in wing or blade performance. The objective of this thesis is to understand the transient dynamics of LSBs in unsteady conditions that are relevant to practical applications of low chord Reynolds number wings and turbine blades. To this end, a series of wind tunnel experiments were performed on a set of NACA 0018 airfoil and wing models at chord Reynolds numbers ranging from 40000 to 100000. The influence of isolated ramp changes in Reynolds number, isolated ramp changes in angle of attack, and large-scale high-intensity free-stream turbulence on the LSB development and aerodynamic loading were investigated. Three-dimensional end effects on LSB development, which are present for all real wings and turbine blades, were also studied in unsteady operating conditions. Two-component particle image velocimetry measurements were performed to investigate the suction surface boundary layer development on the wing and airfoil models. Direct force measurements were employed to quantify the effects of unsteadiness on the lift coefficient.
Transient changes in free-stream velocity and angle of attack leading to LSB formation or bursting were found to produce lift coefficient hysteresis. Stronger hysteresis effects were observed for more rapid changes in operating conditions, and for two-dimensional airfoils relative to finite wings. Although the dynamics of boundary layer transition affect the conditions at which LSB bursting or formation initiates, the temporal evolution of the aerodynamic forces after the onset of LSB bursting or formation were similar across widely varying flow conditions. When undergoing an increase in angle of attack that leads to bursting, the LSB initially contracted. In contrast, the LSB continuously expanded prior to bursting during a decrease in Reynolds number. However, LSB formation was followed by a contraction of the LSB during both decreases in angle of attack and increases in Reynolds number. The frequencies of unstable disturbances that lead to transition in the separated shear layer varied continuously during the LSB formation and bursting transients. The duration of the LSB bursting and formation transients was on the order of 10 global convective timescales. On a finite span wing, end effects caused spanwise expansion of the separated flow region during bursting. Conversely, the separated flow region contracted in the spanwise direction during LSB formation on a finite wing. The gradual spanwise progression of bursting on a finite wing in unsteady conditions caused changes in aerodynamic loads that were more gradual than those experienced by a two-dimensional airfoil. In large-scale, high-intensity free-stream turbulence, fluctuations in the instantaneous effective oncoming velocity direction may lead to large variations in transition location and intermittent boundary layer separation. These findings elucidate the physical mechanisms responsible for the performance characteristics of wings and turbine blades in unsteady low chord Reynolds number flows
Toward Adaptive Planar Magnetic Levitation Systems for Variable Load Transport: Design and Estimation Strategies
No full textMagnetic levitation offers unique advantages for industrial automation—frictionless actuation, silent operation, and fully decoupled multi-degree-of-freedom (DOF) motion—but these benefits are often offset by practical challenges in real-world deployment. In particular, sensitivity due to misalignment in mover and stator magnetic fields, manufacturing tolerances, and external disturbances from variable payloads. These limitations make it difficult to deploy levitation platforms in dynamic environments where the mass and location of transported objects cannot be tightly controlled. Motivated by a growing demand for intelligent transport systems in flexible manufacturing lines and collaborative robotic workcells, this research presents the development of an adaptive control strategy for planar magnetic levitation systems capable of estimating unknown payload mass and center-of-mass location data in real time. Performance in the face of variable payloads maintains stability and preserves control performance across a wide range of operating scenarios.
An adaptive linear quadratic regulator (ALQR) framework was implemented on two planar Halbach-array-based mover units—one with a 6-pole configuration and another with a 5-pole layout. The control architecture incorporates online parameter estimation to recover payload characteristics from force and torque measurements without requiring extensive prior calibration or external measurements of the load. This enables the system to dynamically compensate for mass disturbances and maintain control accuracy across varying operating conditions.
Experimental validation shows that the 5-pole array achieves an average payload mass estimation error of less than 2% of the true value, with the payload’s center of mass localized within ±1.9cm. For the 6-pole mover array, the average mass estimation error is below 4%, and the location estimation error is within ±0.5cm. These results varied across multiple stator locations and mover configurations. A series of experiments—including sequential payload loading, off-center placement, and mid-trajectory dynamic loading—demonstrated the estimator’s robustness and its resilience to transient noise and visual occlusion artifacts. To support consistent estimator performance across the stator, a compensation method was developed to account for geometric deviations in the stator. This included a payload mass offset profile derived through iterative calibration, which enables accurate levitation and estimation throughout the workspace without relying on predefined lookup tables. When tracking motion trajectories, the adaptive controller and mass offset profile significantly reduced steady-state error in the payload mass estimation following load application—from 25% to below 3%—and improved vertical and yaw response times when compared to a fixed-parameter LQR control scheme.
Together, these contributions demonstrate a magnetic levitation platform suitable for collaborative and flexible automation tasks. The system adapts to unknown payloads in real time, estimates key inertial parameters during operation, and maintains performance without requiring redesign or calibration for each payload. These capabilities form a foundation for future research in multi-agent manipulation, intelligent load sharing, and sensorless coordination in levitated transport systems
Hydroclimatic influence of seismic line disturbances based on field measurements and modelling across Alberta, Canada
No full textGeologic exploration for petroleum has resulted in a dense network of seismic lines—linear clearings—across the boreal forest, yet their effects on hydrometeorological conditions remain understudied. With a focus on peatland ecosystems, this study used a combination of field-based measurements and hydrological modelling (CoupModel) to investigate the impact of seismic lines on wintertime hydrometeorological conditions, summertime evapotranspiration (ET), and the annual water balance for study sites in Alberta, Canada. Winter assessments revealed that photosynthetically active radiation (PAR) was 1.8 times higher on seismic lines than in the adjacent forest understory, with greater negative net radiation (i.e., high outgoing radiation for the ground surface) also observed. Wind speeds on seismic lines during the unfrozen period were significantly elevated, 8 times higher at an east-west site and 7 times higher at a north-south site, compared to the adjacent undisturbed peatlands. Soil temperatures remained above freezing for seven days longer on the lines, suggesting thermal insulation effects caused by the deeper snowpack observed on the seismic lines. Snowpack dynamics captured by time-lapse photography across upland and peatland sites showed a 5 cm higher maximum snow depth on seismic lines, and a 3 cm greater average snow depth, though the latter was not statistically significant. Snow depth declined more rapidly on seismic lines, but with maximum depth reached five days later, snow-free conditions occurred one day later despite an ablation duration five days shorter than in undisturbed areas. Actual ET (AET) from the ground layer on seismic lines in peatlands was 59% and 14% higher than adjacent areas based on lysimeter and chamber measurements, respectively. Soil temperature, PAR, and plant composition were key drivers of chamber-based AET, while lysimeter-based AET was mainly influenced by PAR and wind speed. Potential ET (PET) was 51% higher on seismic lines, raising the Priestley-Taylor coefficient (α) from 0.61 to 0.73. While not directly measured, tree transpiration estimates from the literature were applied, which revealed that seismic line AET still surpassed that of adjacent areas with an intact tree cover by 31%. Comparing 1-D simulations for on and off seismic line conditions for peatlands from a process-based hydrological model (CoupModel) supported field-based findings, indicating higher soil moisture, temperature, and shallower groundwater depths on seismic lines. The simulated AET was 6% higher on the lines, largely driven by moss evaporation, which compensated for lost canopy transpiration. Despite higher ET, increased precipitation that reaches the ground surface and lateral flow led to 5 mm more water storage on seismic lines. Model sensitivity analysis revealed that an increase in soil compaction substantially elevated runoff, drainage, soil moisture, and storage. The seismic line had a greater difference in conditions from offline areas when peatland canopy LAI was greater; the undisturbed condition with higher LAI resulted in higher transpiration, and cooler soils. Overall, the findings illustrated that seismic line clearing results in measurable local changes in hydrological conditions; future research should explore the impact of seismic lines on the catchment scale to better understand the cumulative impact of these disturbances on hydrological processes in boreal ecosystems
On Culpable Ignorance: Answering the Debate between Epistemic Vice and Internalism
No full textImagine I invite you over for tea. I ask you if you want any sugar in your tea and you say “yes, please!” So I take the sugar bowl out of my cupboard and spoon some sugar into your tea. Little do I know, someone had snuck into my house in the middle of the night and switched out the sugar in my sugar bowl with arsenic. You drink the arsenic tea and fall deathly ill. By putting what I think is sugar into your tea, I cause you to fall ill and potentially cause your death. But all along, I had no idea that the contents of my sugar bowl was arsenic, not sugar. Am I blameworthy for poisoning you?
The topic of when an agent can be held responsible, or culpable, in cases where they did not know what they were doing has gained attention in recent years. The field of culpable
ignorance aims to look at when agents are culpable for unwitting wrongful acts performed from ignorance, and what criteria must be fulfilled to judge an agent as morally responsible for her wrongdoing.
I am to defend a version of what is called the Epistemic Vice View held by William FitzPatrick, which states that normative ignorance can be culpable if it is a result of epistemic vices such as arrogance, laziness, or dismissiveness, given that the agents could have reasonably remedied their ignorance had they not exercised such epistemic vice. However, it has been met with critique. I focus on Neil Levy’s Internalist critique, which states that what an agent can reasonably know and have done is a state internal to the agent herself.
I argue that Levy is incorrect in his internalism because his theory is founded on two false assumptions. In doing so, I hope to defend FitzPatrick’s Epistemic Vice View. I argue that the Epistemic Vice View captures our intuitions about blameworthiness, while also avoiding the extremes of both excusing all ignorance and condemning all unwitting wrongdoing. My defense contributes to the broader debate by offering a nuanced standard for culpable ignorance, one that preserves the integrity of moral responsibility without requiring radical revision of our practices of blame.
In the first chapter, I introduce the topic of culpable ignorance, and delineate the main ways theorists aim to solve the issue. In the second chapter, I outline the debate between William FitzPatrick and Neil Levy. Finally, in the third chapter, I pose critiques to Levy’s internalist position
Revivifying, Repurposing, Reimagining: From Commodification to Kinship in 21st-Century De-Extinction and Xenotransplantation Narratives
No full textDe-extinction and xenotransplantation represent two key 21st-century biotechnological developments, both of which aim to use genetic engineering to address ecological and medical crises. This dissertation investigates the representation of de-extinction and xenotransplantation by scientific corporations, in the media, and in fiction. In particular, I draw on critical posthumanist theory to investigate how techno-optimistic and transhumanist rhetoric has influenced de-extinction and xenotransplantation narratives; how narratives respond to key issues in bioethics and environmental ethics; the implications that these narratives suggest for how biotechnology is shaping human and nonhuman identity; and the way that they explore possibilities for multispecies care, kinship, and entanglement. My analysis in Part I shows that de-extinction is frequently framed in terms of the biomedical and human health benefits that it can offer. While this biomedical framing is reflected in the Jurassic World films (2015, 2018, 2022) and the novels Ghost Species (2020) and The Neanderthal’s Aunt (2014), these narratives focus on the risks arising from the exploitation and commodification of genetic material. In my analysis of xenotransplantation narratives in Part II, I observed that pigs are frequently framed as an abundant supply of organs that can solve the organ shortage crisis. In contrast, the novel Pig-Heart Boy (1997) and the film We Ate the Children Last (2011) focus on the bioethical risks faced by the first patients to undergo xenotransplantation, such as their vulnerability and the risk of discrimination, while the novels Oryx and Crake (2003) and Chromosome 6 (1998) counter the frame of abundance by depicting the potential for detrimental environmental, political, and economic impacts. Lastly, my analysis in Part III of the short story “The Birdsong Fossil” (2021) and the novel Pighearted (2021) reveals that these narratives prioritize care, kinship, and entanglement, providing possibilities for reimagining the animals created by biotechnology beyond the hype of charismatic megafauna and the spare parts metaphor in de-extinction and xenotransplantation discourse. By drawing on multispecies environmental ethics and posthumanist bioethics, I conclude that these narratives can allow us to envision more ethical applications of biotechnology, which can thereby shape the future of de-extinction and xenotransplantation
Understanding International Graduate Students' Housing Experiences.
No full textThe global rise in international graduate student mobility has intensified housing pressures in host cities, exposing gaps in institutional support and affordable housing provision. In Canada, particularly in Kitchener/Waterloo, Ontario, international graduate students experience growing difficulty securing adequate and affordable accommodation. Despite their financial and academic contributions, this group remains underrepresented in housing policy and planning research. The main problem addressed in this study is the mismatch between increasing international graduate enrolments and the inadequate housing infrastructure and policies designed to meet their needs. Existing research focuses largely on undergraduate student housing or general urban affordability, leaving a significant research gap concerning the lived experiences of international graduate students and the structural factors shaping these outcomes.
The study draws on Housing Pathway Theory (Clapham, 2002, 2005) as its primary theoretical framework, emphasizing housing as a dynamic, non-linear process shaped by the interaction between individual agency and structural constraints. To enhance explanatory depth, the study integrates Bourdieu’s conceptual triad of habitus, capita, and field (1984,1986). This combined framework highlights how different forms of capital, economic, cultural, and social interact within the housing field to influence students’ pathways, constraints, and adaptive strategies. Together, these theories explain how international graduate students navigate the tension between structural housing limitations and their personal resources, revealing how inequalities in capital shape distinct housing trajectories.
The research employed a mixed-methods, cross-sectional and case study design. Primary data were collected through an anonymous online survey and follow-up interviews to international graduate students who opted to be interviewed. Purposive and snowball sampling yielded 125 valid responses from an initial 136. Quantitative data were analyzed descriptively using SPSS (Version 28) to identify patterns of affordability, accessibility, and housing satisfaction, while qualitative responses underwent thematic analysis using NVivo 15 to interpret lived experiences and coping strategies.
The major findings reveal that international graduate students face acute housing precarity, with affordability, discrimination, and limited information networks as central challenges. High rents and the dominance of PBSA developments have marginalized students with limited financial capital. Cultural and social capital strongly influenced housing outcomes: those with local networks or prior Canadian experience navigated markets more effectively. Many respondents reported overcrowded, temporary, or substandard conditions that negatively affected their well-being and academic performance. The findings also expose structural inequalities embedded in municipal housing markets and institutional policies, which privilege domestic or undergraduate cohorts.
Policy implication highlights the need for universities, municipal authorities, and provincial housing agencies to develop integrated housing strategies that recognize international graduate students as a distinct and vulnerable demographic. Recommendations include expanding affordable housing supply through university–municipal partnerships, improving access to tenant education and legal resources, and ensuring that institutional housing policies reflect the diversity of students’ economic and cultural needs. By centering international graduate students lived experiences, this study contributes to academic discourse on housing inequality and provides actionable insights for designing inclusive and sustainable student housing frameworks
Hormonal regulation and plasma volume during 60-days of head-down bed rest with exercise during artificial gravity
No full textReductions in plasma volume (PV), a hallmark of spaceflight and its analog head-down-bed rest (HDBR), trigger compensatory releases of renin and aldosterone to promote fluid retention. Artificial gravity (AG) and exercise have been proposed to counteract PV reductions during HDBR, but optimal protocols remain undefined. We investigated how simultaneous exercise and AG affects volume-regulating hormones and PV during HDBR compared to exercise or sedentary control groups. We hypothesized that exercise+AG would protect PV and maintain volume-regulating hormones at pre-HDBR levels, outperforming exercise and sedentary control groups. Twenty-four healthy males (29±6 yr) underwent 60 days of 6° HDBR and were assigned to sedentary control (n=8), exercise (n=8), or exercise+AG (n=8) groups. Exercise group participants performed near daily 30-minute supine moderate-to-high-intensity interval cycling throughout HDBR, while exercise+AG participants performed the same exercise during 30 minutes of short-arm centrifugation with head-to-foot gravitational profiles based on resting G tolerance tests. Changes in PV, fluid-regulating hormones, and erythropoietin were assessed using carbon monoxide rebreathing and biochemical assays. HDBR reduced PV (p<0.001), blood volume (p<0.001), and hemoglobin mass (p<0.001) in all groups, and reductions were inversely correlated with an increase in active renin (all p<0.05; rrm=-0.615, rrm=-0.553, rrm=-0.426, respectively). Erythropoietin was reduced at HDBR day 3 (p<0.001) irrespective of group. Exercise+AG responses did not differ from the exercise or control groups, with countermeasures failing to maintain PV or blunt fluid-regulating hormone release. These results contrast work showing benefit of gravity-like exposure after exercise on PV and suggests that AG should not be applied exclusively during exercise
Restless Legacies and Troubled Memories: The Historical Realities of the Organization of Ukrainian Nationalists
No full textThe turbulence of Ukraine’s contemporary political climate has resulted in a resurged admiration for the Organization of Ukrainian Nationalists (OUN) whose legacy is marred with accusations of ethnic cleansing, including participation in the Holocaust, subscription to fascist ideology, extended use of political violence, and alignment with Nazi Germany. Apologists for the OUN seek to deny these controversies, deeming them false and de-contextualized Soviet, Polish, and Jewish narratives. Critics of the OUN point to the extensive evidence against the OUN and argue that the opening of the Soviet archives before their subsequent closure only added evidence to their arguments. This thesis seeks to examine the major points of contention and test the validity of these interpretations
Immersion, Roleplaying, Narrative Design: Concepts for Understanding Videogame Narrative
No full textSingle-player videogames have been at the forefront of public and academic conversations about the supposed novelty of digital, interactive narratives for the past 30 years. This perceived novelty, together with the digital medium’s capacity for remediating the aesthetics of prior popular media such as novels, film, performance, and of course games, has spurred conflicting discussions about its ontological and teleological nature. Whether one listens to game scholars, developers, or players, there is no single answer that encapsulates the wide range of disciplinary perspectives and personal fixations that make videogames interesting and meaningful. This project therefore synthesizes a range of research across disciplines to address a longstanding yet still insufficiently explored area of videogame inquiry: their historical creation, function, and consumption as a form of narrative.
This dissertation examines how narrative meaning in single-player videogames emerges in the interaction between the material, rhetorical, and formal properties of the game as well as the imaginative engagement and individual experience of a given player. In other words, it delves into how narrative has been conceived and discussed around games, how players cultivate and interpret their gameplay as a narrative experience, and how developers leverage the multimodal potential of videogames towards narrative-driven expression.
It does so through a synthesis of research around three interrelated key terms: immersion, role-playing, and narrative design. The terms immersion and roleplaying help explore how a player’s involvement in the role of a digital avatar—established through the identity and affordances presented by the game’s design and the player’s creative engagement with those fixed elements—can offer a means for subject formation, self-reflection, and critical interpretation. This involves exploring these concepts’ relations between narrative (Murray), digital technology (Coleman), and the self (Gee). The project then examines how this critical engagement textually stems from the player’s experience of a game’s narrative design: a game design concept and development practice related to the coherent integration of a game’s processes, its representational content, and the thematic and subjective meanings players uncover through the narrative event of gameplay (Berger). This framework can help develop greater literacy of the unique ways in which a videogame’s textual meaning is co-constructed between a game’s procedurality, representations, creators, and players.
These topics are supported by case studies of games—predominantly role-playing games, or RPGs—that leverage the expressiveness of the medium towards innovations in digital, interactive storytelling. By situating these discussions of videogame narrative with texts that tackle videogames’ unique media aesthetics (Calleja), indebtedness to prior media (Saler), black-boxed creation process (Švelch), genre in cross-cultural creative contexts (Hutchinson and Pelletier-Gagnon), historical marginalization and entanglements with queer (Ruberg) and femme (Chess) folks, and other relevant topics, this dissertation analyzes the ways that single-player videogames can offer narrative experiences that combine the aesthetic and technical in ways that recontextualize the self’s involvement in fictional engagement