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A LEGACY OF RENEWABLE ENERGY USING MINING AREAS AS AN ENERGY HUB: CASE STUDY “LA JAGUA MINE” (COLOMBIA)
No full textIt is widely acknowledged that variable renewable energy sources (VRES), such as solar and wind, are not dispatchable sources that can offer the global energy system the affordability, stability, and reliability that is currently required. The variable nature of solar and wind energy sources presents a significant challenge to the global energy system in achieving its net-zero emissions reduction goals for CO2. A variety of technologies have been developed with the objective of addressing this issue by storing energy for when solar irradiance and wind speeds are insufficient to supply the need. Pumped hydro energy storage (PHES) is regarded as one of the most cost-effective and environmentally benign forms of energy storage. This research investigates the potential for a second life for mining areas enabled by renewable energy generation in conjunction with PHES technology. It considers the potential for PHES to provide a positive legacy for regions hosting intensive mining operations as compensation through the provision of affordable electricity. The feasibility of utilizing renewable energy in brownfield and greenfield sites was evaluated, identifying a significant prospect for sustainable development in mining regions. However, the creation of regulatory frameworks, development strategies and rules are necessary to fully leverage this energy potential. Furthermore, there is a dearth of knowledge and consensus among stakeholders regarding the repurposing of mines with hydro energy storage technology.It is widely acknowledged that variable renewable energy sources (VRES), such as solar and wind, are not dispatchable sources that can offer the global energy system the affordability, stability, and reliability that is currently required. The variable nature of solar and wind energy sources presents a significant challenge to the global energy system in achieving its net-zero emissions reduction goals for CO2. A variety of technologies have been developed with the objective of addressing this issue by storing energy for when solar irradiance and wind speeds are insufficient to supply the need. Pumped hydro energy storage (PHES) is regarded as one of the most cost-effective and environmentally benign forms of energy storage. This research investigates the potential for a second life for mining areas enabled by renewable energy generation in conjunction with PHES technology. It considers the potential for PHES to provide a positive legacy for regions hosting intensive mining operations as compensation through the provision of affordable electricity. The feasibility of utilizing renewable energy in brownfield and greenfield sites was evaluated, identifying a significant prospect for sustainable development in mining regions. However, the creation of regulatory frameworks, development strategies and rules are necessary to fully leverage this energy potential. Furthermore, there is a dearth of knowledge and consensus among stakeholders regarding the repurposing of mines with hydro energy storage technology
Invisible groundwater threats to coastal urban infrastructure
No full textGroundwater-associated hazards in coastal cities can be as acute as surface flood hazards, but are often overlooked, more persistent, and harder to identify. Here we discuss how climate change is causing flooding and corrosion of coastal infrastructure by driving groundwater rise and salinization
Reasons for music listening, preferred musical attributes, and choice of song lyrics vary by listener anxiety sensitivity levels
No full textThis research explored how anxiety sensitivity—the tendency to fear sensations associated with anxiety—shapes the way people use music and their musical preferences. The results suggested individuals higher (versus lower) in anxiety sensitivity differ in their reasons for listening, the acoustic features they prefer, and the lyrical content they select. These findings point to the potential for personalized, music-based strategies to help support emotional well-being.Across three studies, this work charted how anxiety sensitivity (AS)—fear of arousal‐related sensations—relates to music engagement at motivational, perceptual, and semantic levels. Study 1 used exploratory factor analysis to identify core reasons for music listening among 788 undergraduates (77.7% women; Mage = 19.20, SDage = 2.46) and explored associations with AS via hierarchical regression. Higher AS predicted relief‐oriented Coping, Conformity, and Connection motives but did not influence reward‐focused Revitalization, Social Enhancement, and Sensory–Motor functions. Study 2 presented 1040 participants (75.3% women; Mage = 19.31, SDage = 3.27) with vignettes designed to prime AS physical, cognitive, or social concerns. Contextual listening endorsement rates were probed via logistic regression and preferred acoustic properties of participant‐nominated tracks were investigated using generalized linear models. Higher AS cognitive and social concerns were associated with greater endorsement of listening but only in a low‐mood context. Higher AS physical concerns were linked to quieter music choices across all scenarios, and higher AS cognitive concerns to faster tempos under low‐mood conditions. Musical mode (i.e., choice of major versus minor key) was not related to AS but the probability of choosing minor key music was lowest in a low-mood context, higher in a social context, and highest in context of physical exercise. Across all scenarios, males were more likely than females to select minor key music. Using LIWC-22 software, Study 3 (also N = 1040; 75.3% women; Mage = 19.31, SDage = 3.27) examined associations between AS and the lyrical content of participant-nominated songs. As predicted, negative binomial regression modeling showed higher AS concerns that matched those primed by a vignette were associated with lyrics containing fewer fear‐relevant words. In contexts incongruent with AS concerns, however, listeners appeared to sometimes avoid, but also (or alternatively) seemed to gravitate toward emotionally charged lyrics, possibly reflecting efforts at exposure or cognitive reappraisal. Together, these findings paint a nuanced portrait of connections between AS and why people listen to music, and which acoustic and lyrical features they choose. Music‐based interventions tailored to individual AS profiles may offer an accessible and effective means of preventing and treating AS‐related emotional disorders
The Development and Evaluation of Nature Matters: an Evidence-Informed Program for Increasing Nature-Focused Behaviours and Nature Connection in Undergraduate Students
No full textMental health difficulties and stressors are prevalent amongst undergraduate students, whereas resources to support students’ mental health are limited. The well-documented benefits of exposure to, and connection with, nature include various aspects of mental, physical, and cognitive health, yet many people are unaware of these benefits and do not engage with nature as a health behaviour. This dissertation describes the development and evaluation of Nature Matters, an online evidence-informed wellness program that integrates the behavior change wheel framework with evidence-based learning strategies to raise undergraduate students’ awareness of the benefits of exposure to nature and encourage behavior change. In Study 1 (N = 108), I assessed the usability and acceptability of Nature Matters using a mixed-methods design. Both quantitative and qualitative results indicated that the program was well-received by undergraduate students, with positive ratings attained for all user-experience domains (1. Perspicuity or clarity/ ease of understanding, 2. Stimulation, 3. Usefulness, 4. Attractiveness, 5. Visual Aesthetics, 6. Trustworthiness of Content, and 7. Quality of Content). In Study 2, I examined if completing Nature Matters 1) enhanced connectedness to nature, 2) increased frequency of exposure to nature; and 3) increased frequency of noticing nature. As hypothesized, participants who completed the program (n = 45) reported greater connectedness to nature and a higher frequency of exposure to nature compared to control participants (n = 46), after accounting for baseline scores. Results for noticing nature were not significant. Exploratory regression analyses revealed that lower baseline levels of nature connectedness, noticing nature, and exposure to nature were all associated with a larger change in post-program outcome scores. Overall, the findings demonstrate the acceptability and effectiveness of Nature Matters for an undergraduate population, suggesting that this program has potential as an intervention for increasing exposure to and connection with nature. Building upon this evidence will advance the utilization of the human-nature connection for improving well-being and pave the way for the development of similar wellness programs
Model Predictive Control for Autonomous Sailboat with Sail Angle Optimization and Trajectory Planning Under Stochastic Winds
No full textThis thesis investigates the development and implementation of model predictive control (MPC) frameworks for autonomous sailboat control under different wind conditions. The research is motivated by the need for robust, constraint-aware control strategies for sailboats, that can effectively handle the nonlinear dynamics and environmental uncertainties.
The study begins with a comprehensive modelling of sailboat dynamics, incorporating sailboat kinematic and kinetics and wave disturbances. Two simulation-based studies both using MPC are then conducted. The first study focuses on sail angle optimization and trajectory tracking, where the control objective is to maximize sailing speed with safety considerations and then achieve accurate trajectory tracking. The second study addresses stochastic wind sailing, where an NMPC-based path planning and tracking controller is designed and evaluated. This controller integrates the controllability analysis to improve performance under both deterministic and stochastic wind conditions. Comparative simulations highlight the advantages of the proposed approach. Then, an experimental platform is instrumented on a small-scale physical autonomous sailboat. This platform integrates the ArduPilot control stack, hardware components and supporting software infrastructure. System identification techniques are applied to extract sailboat’s dynamic model, and experimental trials are conducted to assess the controller performance in real-world conditions.
The results demonstrate that MPC offers a viable and effective solution for autonomous sailboat control, capable of addressing both operational constraints and environmental variability
Victorian Racial Science: Manifestations in Judicial and Legislative Procedures in British India
No full textWorking Tidal: Making Peace with the Avon River
No full textThis thesis explores the role of architecture in mediating ecological restoration and social reconciliation along the Avon River in Windsor, Nova Scotia. In response to the contested legacy of the Windsor Causeway, the project proposes a tidal amphitheatre, a pedestrian bridge, and an indoor theatre, each designed to respond to the Bay of Fundy’s tidal rhythms. Drawing from fluvial geomorphology, Indigenous treaty rights, and climate adaptation, the design frames water as a collaborator rather than an obstacle. The architecture responds to the movement of the River, turning parts of the site into spaces where people can witness the tide’s return. Through sensory engagement and ecological integration, the project reimagines public infrastructure as both a learning space and a tool for participation. Rather than offering fixed solutions, the architecture embraces change, acting as a medium that communities can witness, respond to, and begin to repair the ecological and cultural divide of a fragmented river system
Strengthening and homogenizing strategies for PH13-8 Mo (CX) stainless steel manufactured via additive manufacturing
No full textPrecipitation-hardening stainless steels (PHSSs) offer a unique balance of high strength, corrosion resistance, and moderate toughness, making them well-suited for critical applications in aerospace, tooling, and injection molding. This thesis focuses on processing PH13-8Mo stainless steel using two AM techniques: Wire Arc Additive Manufacturing (WAAM) and Laser Powder Bed Fusion (LPBF) with the aim of enhancing densification, controlling microstructure, and improving mechanical and tribological performance through the incorporation of ceramic particles and post-processing heat treatments.
In the first phase, WAAM was used to fabricate PH13-8Mo components. The as-printed parts exhibited a columnar structure along with δ-ferrite and retained austenite, leading to anisotropic wear behavior. Post-processing heat treatments including solutionizing at 1050 °C and aging at 400–600 °C were applied. Aging at 500 °C yielded a fully martensitic microstructure and nanoscale β-NiAl precipitates. These transformations significantly enhanced hardness and wear resistance while minimizing friction and eliminating anisotropic wear response.
The second phase examined the addition of TiC and TiB₂ nanoparticles during WAAM to refine grains and improve wear performance without relying solely on heat treatment. Both nanoparticles refined the grain structure and increased retained austenite content, while TiC provided the best wear resistance due to its excellent balance of hardness and fracture resistance as well as its ability to promote strain-induced martensitic transformation during sliding contact
The third phase of this work focused on the LPBF processing of TiC reinforced PH13-8Mo SS powder (CX SS). A central composite design approach was adopted to evaluate the influence of laser power, scan speed, hatch spacing, and layer thickness on densification behavior across samples reinforced with 0–2 wt.% TiC. The TiC-reinforced alloys showed a broader process window and improved densification, achieving up to 100% relative density compared to 99.4% in the unreinforced counterpart.
In the final phase, the mechanical behavior of LPBF-processed PH13-8Mo with TiC reinforcement was investigated. The addition of TiC simultaneously enhanced strength and ductility. The 1 wt.% TiC composition exhibited great combination of ultimate tensile strength (~1232 MPa) and elongation (~35.7%), attributed to grain refinement, retained austenite stabilization, and uniform particle distribution. Strengthening mechanisms included grain boundary strengthening, dislocation hardening, transformation-induced plasticity (TRIP), Orowan looping, and load transfer. Following heat treatment, particularly solution-aging, the 2 wt.% TiC sample achieved the highest strength (~1990 MPa) due to the combined effects of nano-precipitated β-NiAl and refined grain structure.
Overall, this work advances the understanding and application of WAAM and LPBF for PHSSs. It offers practical strategies for microstructure control, mechanical and wear performance enhancement using ceramic reinforcement and targeted thermal treatments
BOWHEAD WHALE BODY CONDITION IN A CHANGING ARCTIC ECOSYSTEM
No full textClimate-induced changes, particularly ocean warming and sea ice loss, may alter primary and secondary productivity in the Arctic Ocean, with cascading bottom-up effects for higher consumers. However, it is unknown how shifts in prey quality and quantity will impact the foraging success of bowhead whales (Balaena mysticetus) from the Eastern Canada-West Greenland (EC-WG) population. To assess the foraging success of the EC-WG bowhead whale population, I calculated body area index (BAI) as a metric of body condition using photogrammetric measurements obtained from 463 individuals. Aerial drone imagery (images and/or videos) were collected during summer over eight years (2016-2023) from Cumberland Sound (a foraging area), Nunavut. My objectives were to 1) compare the BAI of different age-sex groups to determine which EC-WG population segments were vulnerable, and 2) examine whether interannual variability in BAI was correlated with any environmental variables (e.g., sea ice conditions, major climate indices) over time. When length-based age-class data was pooled, I found that the Cumberland Sound habitat favoured a larger proportion of immature whales (juveniles and subadults), with younger (or shorter) age-classes (calves, yearlings, juveniles) in better body condition than older age-classes (subadults and adults). By combining measurements with biopsy (sex and epigenetic aging) results, I also confirmed that there was a skew towards male (44:22) and sexually immature (1+ to 23 years of age) whales. While the annual mean BAI varied within a small range of value (~31-33), fluctuations corresponded with changes in oceanographic conditions. Using generalized linear models, I found that improvements in body condition were positively correlated with lagged (1 to 3 years) environmental variables, including sea ice phenology (freeze-up and sea ice duration) and a positive summer North Atlantic Oscillation index, with the latter linked to increases in secondary productivity. Year was negatively correlated with BAI, suggesting a potential decline over the short timeseries consistent with a reversal in NAO phase. Overall, my findings provide insight about the body condition of the recovering EC-WG bowhead whale population, including previously under-represented age-classes, and how changes in health may occur on delayed timescales following episodic events