UWSpace

UWSpace is the University of Waterloo’s institutional repository for the free, secure, and long-term home of research produced by faculty, students, and staff.

Depositing Theses/Dissertations or Research to UWSpace

Are you a Graduate Student depositing your thesis to UWSpace? See our Thesis Deposit Help and UWSpace Thesis FAQ pages to learn more.

Are you a Faculty or Staff member depositing research to UWSpace? See our Waterloo Research Deposit Help and Self-Archiving pages to learn more.

Photo by Waterloo staff

Communities in UWSpace

Select a community to browse its collections.

Recent Submissions

  • Thumbnail Image
    Item type: Item ,
    Seeing past the clutter: what stuff really matters?
    (University of Waterloo, 2026-03-27) Robichaud, Danielle
    The stuff in our lives is inescapable. Objects, souvenirs, and the items that signal who we are to the world carry deep meaning to us making the process of figuring out what to do with it all a daunting challenge. Drawing on lived experience navigating the death of a parent, the relocation of another, and the professional training of an archivist, this talk will explore the complicated relationship we all have with stuff and the need to get comfortable with letting it go by focusing on what really matters.
  • Thumbnail Image
    Item type: Item ,
    Effects of Heat Treatment on the Temperature Coefficient of Resistivity of Laser Fabricated NiCr Flexible Sensors
    (University of Waterloo, 2026-04-15) Almomani, Hashem
    Advancements in automation, flexible electronics and embedded sensing systems has increased the demand for specifically designed and customizable sensors. This includes thin film resistive sensors with customizable electrical properties and long-term stability. Nickel chromium (NiCr) alloys are widely used in resistive sensors due to their chemical stability, high resistivity, and low temperature coefficient of resistivity (TCR); however, controlling TCR remains a challenge in novel sensor fabrication methods, such as laser ablation. Laser ablation offers a promising alternative to conventional lithography-based fabrication due to its low process complexity, rapid prototyping capabilities, and compatibility with flexible substrates. In this work, NiCr thin films were heat treated over a range of temperatures and hold times to modify their electrical and microstructural properties. Following heat treatment, the thin film samples were hot pressed between two polyimide sheets and patterned into flexible resistive sensors using UV laser ablation. The laser fabrication process was optimized through investigation of processing parameters, including laser power, number of passes, and environmental factors. The influence of these parameters on feature geometry, resistance control, and fabrication repeatability was evaluated, and laser fabricated sensors were benchmarked against commercially manufactured resistive sensors. Heat treatment was found to significantly reduce the magnitude of TCR, while improving resistance stability. Microstructural and compositional changes were characterized using scanning electron microscopy, energy dispersive x-ray spectroscopy, and x-ray photoelectron spectroscopy. The results indicate that surface compositional changes and oxidation influence electrical properties more than bulk changes in thin films. These findings demonstrate that pre-fabrication heat treatment is an effective strategy for tailoring the TCR of laser fabricating NiCr thin film sensors for flexible sensor applications.
  • Thumbnail Image
    Item type: Item ,
    Some results on hypersymplectic structures
    (University of Waterloo, 2026-04-14) Petcu, Amanda
    A conjecture of Simon Donaldson is that on a compact 4-manifold X⁴ one can flow from a hypersymplectic structure to a hyperkähler structure while remaining in the same cohomology class. To this end the hypersymplectic flow was introduced by Fine–Yao. In this thesis the notion of a positive triple on X⁴ is used to define a hypersymplectic and hyperkähler structure. Given a closed positive triple one can define either a closed G₂ structure or a coclosed G₂ structure on 𝕋³ × X⁴. The coclosed G₂ structure is evolved under the G₂ Laplacian coflow. The coflow descends to a flow of the positive triple on X⁴, which is again the Fine–Yao hypersymplectic flow. In the second part of this thesis we let X⁴ = ℝ⁴ ∖ {0} with a particular cohomogeneity one action. A hypersymplectic structure built from data invariant under this action is introduced. The Riemann and Ricci curvature tensors are computed and we verify in a particular case that this hypersymplectic structure can be transformed to a hyperkähler structure. The notion of a soliton for the hypersymplectic flow in this particular case is introduced and it is found that steady solitons give rise to hypersymplectic structures that can be transformed to hyperkähler structures. Some other soliton solutions are also discussed.
  • Thumbnail Image
    Item type: Item ,
    Evaluating the Impact of Fan Design and Air Speed on User and Nearby Occupants’ Thermal Comfort in a Shared Office
    (University of Waterloo, 2026-04-13) Bayode, Kehinde
    Personal Comfort Systems (PCS) are increasingly recognized for their potential to improve individual thermal comfort and reduce building energy demand. ASHRAE Standard 55 defines PCS as a device, under the control of the occupant, intended to heat and/or cool individual occupants without affecting the thermal environment of other occupants. Desk fans are common PCS cooling devices, but their use in shared workspaces raises questions about the differential impact on the primary user and nearby occupants. Limited empirical evidence exists on how local air speed and fan technology jointly influence thermal, airflow, and acoustic domains among occupants. To address these gaps, a human-subject experiment involving 40 participants was conducted, paired into 20 pairs: P1 as the fan primary user and P2 as a nearby occupant. Two desk fan designs (conventional-blade and bladeless) were tested at high and low-speed settings. Participants provided repeated comfort assessments at each fan speed condition. The results indicate that both fan technology and operating speed significantly affect the alignment or divergence of comfort between P1 and P2. At low speed, both fan types produced strong convergence, with both occupants reporting neutral thermal sensation, slight satisfaction, and a shared perception of air movement as “just right.” In contrast, at high speed, the bladed fan resulted in divergence: P1 perceived the airflow as “too breezy” and preferred less air movement, while P2 reported no change despite experiencing breezy conditions. Conversely, the bladeless design reduced this asymmetry. At all speeds, both P1 and P2 reported neutral thermal sensation and consistent satisfaction. For primary users, both fan types enhanced thermal comfort at both speeds. The bladed fan was effective only at low speed, as high speed produced a “too breezy” sensation, whereas both speeds were acceptable for the bladeless fan. Despite these advantages, the bladeless fan introduced acoustic disturbance to the environment. High-speed bladeless was perceived as more annoying than the bladed fan, with the P2 group reporting higher annoyance (85%) than the P1 group (65%). This suggests that the high-frequency profile of the air multiplier technology is intrusive, especially for nearby occupants in shared environments. For shared workspaces with mechanical cooling, a low-speed fan setting is recommended. This configuration minimizes acoustic annoyance for both fan technologies (0-5% annoyance) while maintaining high thermal satisfaction for primary users and minimal intrusion into the environment of nearby occupants.
  • Thumbnail Image
    Item type: Item ,
    Investigating mitochondrial microRNAs in response to metabolic disruption
    (University of Waterloo, 2026-04-13) Robichaud, Karyn
    Aquatic and terrestrial environments are dynamic due to natural and anthropogenic sources, including pollutants, thermal variability, and hypoxia. These stressors or perturbations can result in changes to energetic demands of animals resulting in metabolic stress. As a major energy transduction site within cells, mitochondria can respond to alterations in environmental conditions and metabolic stress by changing their physiology. Specifically, mitochondrial oxidative phosphorylation may change during stress, resulting in altered oxygen consumption rates and efficiency of energy transduction. These plastic responses of mitochondria can be regulated by post translational modifications to proteins; however post-transcriptional regulation of genes may also alter mitochondrial physiology. Genes can be post-transcriptionally regulated by microRNA; microRNAs are small, non-coding RNA molecules that canonically suppress mRNA expression, and thus protein expression. MicroRNAs regulate nuclear encoded genes in response to a variety of physiological stressors, however microRNA can also redistribute subcellularly into mitochondria. Mitochondria contain their own genome which encodes proteins involved in oxidative phosphorylation, therefore mitochondrial microRNAs (mitomiRs) can also regulate mitochondrial gene expression in response to stress. The overall goal of this thesis was to investigate mitomiRs in animals and predict their potential role in regulating mitochondrial function in response to metabolic stress. Most research on mitomiRs prior to this thesis was conducted in mammals, and with respect to disease. Therefore, this thesis aimed to compare mitomiRs across species, identify whether mitomiRs change in abundance with exposure to different stressors, and predict mitomiR mRNA targets. It was hypothesized that mitomiR abundances differ based on environmental changes (stressor type, stressor duration) and inherent differences (species, sex), resulting in changes to mitochondrial function during metabolic stress. Chapter 2 investigated the mitomiR profiles of zebrafish (Danio rerio) brains under control conditions and during acute exposure to two known metabolic stressors (hypoxia and elevated temperature). Exposure to each stressor resulted in distinct mitomiR profiles, where two mitomiRs were differentially abundant during hypoxia, and another mitomiR had altered abundance during thermal stress. The predicted nuclear targets of these mitomiRs were mainly involved in metabolic pathways, with many distinct predicted targets. Furthermore, brain mitochondrial respiration was only altered during thermal stress, and results indicated a potential decrease in ATP synthesis efficiency. Overall, brain mitochondrial respiration and mitomiR abundances had stressor-specific effects. Chapter 3 investigated whether venlafaxine, an antidepressant commonly found in wastewater effluent, altered zebrafish brain mitochondrial respiration and mitomiR abundances. In vitro, this study first confirmed that venlafaxine suppressed brain mitochondrial respiration. Then, an acute time-course exposure was conducted using zebrafish. In vivo, venlafaxine had minimal effects to brain mitochondrial respiration, however, three mitomiRs were differentially abundant based on exposure, sex, and time sampled. Changes to mitomiR abundance may have been due to their host gene expression, circadian rhythm, and venlafaxine exposure. Chapter 4 utilized three species of wild fish (Etheostoma spp.), to determine if they responded similarly to chronic exposure to wastewater effluent outfall in the Grand River, Waterloo, with respect to mitomiR abundances and mitochondrial function. Wild rainbow (Etheostoma caeruleum), fantail (E. flabellare), and Johnny darters (E. nigrum) were collected from up and down stream of the Waterloo wastewater treatment plant, then liver mitomiR abundances and mitochondrial cytochrome c oxidase activities were measured, and species-specific differences were detected. Results indicated that these darter species had species-specific changes to mitomiR abundances and mitochondrial enzyme activity when living downstream of the Waterloo wastewater treatment plant. Chapter 5 provided a comparative study between vertebrate taxa using a mammal that experiences drastic changes in mitochondrial respiration during torpor and interbout euthermia hibernation states. During torpor, mitochondrial respiration is suppressed and returns to summer values during interbout euthermia. This study profiled mitomiRs in thirteen-lined ground squirrels (Ictidomys tridecemlineatus) during summer and hibernation. Changes in mitomiR abundances were detected during hibernation, and mitomiRs had predicted effects that may indicate their involvement in regulating changes to mitochondrial respiration and function during hibernation. The major finding of this thesis was that mitomiRs are differentially abundant based on stressor, sex, and species, despite some conservation of mitomiRs among species studied. This thesis also predicted targets for differentially abundant mitomiRs within mitochondrial and nuclear genomes, and measured changes in mitochondrial enzyme activities and respiration in fish to provide context for how mitomiRs may aid in regulating mitochondrial function. Overall, this thesis contributed to knowledge of mitomiRs and how they show distinct abundance patterns using a variety of comparative approaches.