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Microwave drying of minerals : experimental and numerical modeling
No full textThis thesis evaluates the application of microwave systems for mineral drying through laboratory
experiments and numerical modeling. Four types of minerals were procured from a mining partner,
with moisture contents up to 25%. Their material properties – including thermal conductivity, heat
capacity, density, initial moisture content, and dielectric loss factor – were characterized. Drying
tests were conducted in a commercial microwave oven, with samples exposed to microwave
irradiation to reduce moisture content to below 1%, while ensuring temperature control below a
specified threshold. Materials were incrementally heated, with mass loss and surface temperature
measured until target mass losses were achieved. Results revealed a two-stage drying regime: a
constant-rate period up to a critical moisture content, followed by a falling-rate regime.
A numerical replica of the commercial microwave oven was developed, including key components
such as three rotating stirrers, a ceramic plate, and three separate magnetrons. Parameters such as
air inflow, stirrer rotation speed, microwave generator ramp-up time, and forward power were
measured and incorporated into the numerical model. The characterized material properties were
integrated into a coupled electromagnetic and heat transfer finite element model implemented in
COMSOL Multiphysics to investigate drying rates and temperature profiles. Predicted mass loss
and temperature changes under experimental microwave heating conditions were compared with
experimental results.
Results indicated that microwave energy was predominantly consumed by water evaporation. For
the studied material M2, which contained sulfur and required maintaining temperatures below
125 °C, the numerical model was particularly useful in determining internal temperatures that were
experimentally inaccessible. The model predicted maximum material temperatures well below 100 °C during 60 s microwave exposures, sustaining an average drying rate of 2 g/s. These findings
demonstrate that microwave heating offers a highly effective alternative for drying applications in
mining, particularly where temperature sensitivity is a key operational requirement.Applied Science, Faculty ofMining Engineering, Keevil Institute ofGraduat
Teaching and learning together : a multiple-case study of D/deaf and hearing teaching partnerships in South Africa
No full textThis qualitative multiple-case study investigates the dynamics of D/deaf-hearing teaching partnerships and their role in supporting emergent South African Sign Language (SASL) literacy in a school for the D/deaf in South Africa. While research in the Global North has highlighted the benefits of D/deaf-hearing co-teaching, particularly in multilingual education contexts, there remains a significant gap regarding how these partnerships function in the Global South, where histories of apartheid, systemic inequalities, and sociolinguistic diversity shape education in complex ways.
South African D/deaf education faces ongoing challenges, including language deprivation, limited access to fluent SASL role models, and a shortage of trained D/deaf teachers; issues compounded by cultural, racial, and linguistic barriers. Although the recent recognition of SASL as an official language marks progress, educational access remains uneven, especially for D/deaf children born to hearing parents, who constitute the majority of the D/deaf population. In this context, some schools rely on co-teaching partnerships where hearing teachers and D/deaf teaching assistants collaborate to promote linguistic and cultural development.
This study explores two such D/deaf-hearing dyads, examining their experiences, perceptions, and pedagogical approaches to supporting early SASL learning. The research draws on semi-structured interviews, classroom observations, WhatsApp conversations, and reflective discussions, framed by an expanded social constructivist perspective incorporating Vygotsky’s deaf pedagogy, plurilingualism (García & Kleifgen, 2010), and insights on practitioner collaboration (Swanwick et al., 2012). A critical, reflexive lens acknowledges the researcher’s position as a hearing-signing, Global South insider-outsider with longstanding ties to the Deaf community in South Africa.
Findings reveal how co-teaching partnerships both challenge and reinforce existing hierarchies, shaped by uneven SASL fluency, shifting role boundaries, and intersecting cultural identities. The study offers new insights into how collaborative, contextually grounded teaching models can promote more equitable SASL literacy development for young D/deaf students in South Africa.Education, Faculty ofLanguage and Literacy Education (LLED), Department ofGraduat
Forest Economics : Revised and Expanded Edition : [supplementary figures]
No full textA firm grounding in economics is integral to sound forestry management, investment, policies, and practices. Forest Economics, Revised and Expanded Edition, offers a full revision of the widely used 2011 text. It covers the basic economic concepts, principles, and constructs and shows how these are applied in private and public forestry decision-making. The goal is to lead readers to understand how to use land, labour, and capital to produce goods and services from forests in ways that will best meet the needs of people. This comprehensive edition – which systematically covers modern forest management, timberland investment, and policy issues – contains new data, examples, and applications of economic principles throughout, along with updated references and study questions. Additional content is provided in several significant new areas: Forest finance and forestland investment/ownership, including financial economic models; Simple interest rate and risk measurements; Market distortion; Consumer theory; Priced non-timber values and payment for ecosystem services; Land rent theory; The economics of forest management planning and forest health/wildfire economics; An international comparison of forest taxes and fees; Property rights beyond the private/public ownership binary; The measurement of competitiveness in international trade; A new theory of foreign direct investment. The advanced empirical presentation and ongoing close attention to new developments in the field reflect the authors’ decades of teaching experience and dedication to smart forest management in the United States and Canada. Forest Economics is quite simply indispensable. This is an integral book for undergraduate and graduate students of forest economics and resource management and policy, as well as for practitioners and investors in timberland and forest industry.Forestry, Faculty ofNon UBCForest Resources Management, Department ofUnreviewedFacult
The independent and interactive effects of dissolved organic carbon (DOC), major salt ions (Na⁺, Ca²⁺) or Cu and pH on osmoregulatory processes of the fish gill
No full textThe ecological roles of dissolved organic carbon (DOC) in aquatic ecosystems are widespread although not yet fully understood, but DOC is likely to impact physiological processes in fish. Generally, DOC is supportive to ionoregulation in freshwater fish, especially in acidic or metal contaminated waters, although the exact protective mechanisms and the influence of water chemistry remain unknown. DOCs can be characterized by optical and chemical indices
but the effect of pH and their inter-relationships are not well understood. I showed that the
indices used to characterize DOC should consider pH and be interpreted carefully as some
changes reflect alterations in conformation (i.e. spatial arrangement of the molecule) while others
reflect changes in composition (i.e. chemical makeup of the molecule) resulting from proton
binding. I also investigated the independent and interactive effects of DOC and pH, major ion
concentrations (Na⁺, Ca²⁺) and/or a potential metal pollutant (copper, Cu) on fish. To explore the
physiological effects of these environmentally relevant DOC-water quality interactions, fish
native to specific habitats with different ionoregulatory strategies were utilized: rainbow trout,
Pacific sanddab and rock sole, and the Amazonian dwarf cichlid. There were independent effects
of major ions (Na⁺ and Ca²⁺), and Cu as well as interactive effects with DOCs which were
altered by a change in pH. Generally, DOC was supportive to ionoregulation against
physiological disturbances caused by ambient pH, major ions or copper. The pH-dependent
physiological responses to DOC may be due to conformation changes in DOC such as
condensation or the titration of the negative net charge on both DOC and the gill leading to more
interaction. Natural DOC sources spanning a wide variety of characteristics, together with model
compounds of known chemistry representing key chemical moieties of natural DOCs, were used.
I demonstrated that specific chemical groups of the DOC molecules (e.g. carboxylic rings,
aliphatic chains, and amino acids (i.e. peptides)) likely play a role in the physiological responses
to natural DOCs. This thesis highlights that the variability in DOC structure and function is
reflected in the physiochemistry of the DOC and in the physiological response of fishes, both of
which are pH-dependent.Science, Faculty ofZoology, Department ofGraduat
Advancing genetic engineering of platelets towards compatibility with common blood banking practices
No full textUncontrolled hemorrhage secondary to trauma is the leading cause of death amongst people from ages 1-46. Platelet transfusions along with whole blood and plasma are the gold-standard for maintaining hemostasis as they detect sites of damage in vasculature and form a clot to stop bleeding. However, in cases of severe bleeding, transfused platelets have limited coagulability making transfusions ineffective, which highlights a critical need for improved platelet products. A promising strategy to overcome current platelet product limitation is to enhance the innate function of platelets by using lipid nanoparticles (LNP) to deliver exogenous cargo.
Optimized LNP loaded with mRNA (mRNA-LNP) are able to engineer platelets to express reporter proteins when suspended in a non-clinical crystalloid solution. The modified platelets retained in vitro physiology, and exogenous protein expression was not correlated with activation, and accumulated in sites of damage when tested in a hemorrhagic model in rats. However, for genetically engineered platelets to be established as a viable cell therapy, this technology would have to be developed with clinical compatibility in mind.
Platelets are currently stored in plasma or in plasma supplemented with platelet additive solution (PAS) at supraphysiological concentrations at room temperature or at 4 ºC, depending on the indications they will be used for. PAS has been developed to support platelet viability during storage, reduce transfusion related adverse reactions, and standardize storage conditions. This thesis describes mRNA-LNP optimized for transfecting platelets directly in plasma or plasma supplemented with PAS and demonstrates scalability to both physiological and supraphysiological platelet concentrations. The process of transfecting platelets with mRNA-LNP in clinical solutions does not affect in vitro physiology, morphology, and their ability to be stored. Aligning the compatibility of this transfection system could enable future mRNA-LNP-based platelet products and other cellular therapies.Medicine, Faculty ofPathology and Laboratory Medicine, Department ofGraduat
Predictive models for personalized support using interaction data in open learning environments
No full textPersonalization during student learning can improve learners' experience by responding to learners in real-time. Various learner signals can be leveraged for personalization during learning such as student's affective states or students' predicted future learning performance. The work in this PhD focuses on building robust predictive models that can drive personalization using real-time sequential interaction data in various open-ended learning environments (OELEs).
First, we look at predicting co-occurring emotions using eye-tracking and interface interaction data in an OELE. Our work combines two datasets with different eye-trackers. We test the effect that combining datasets has on predictions using interaction and eye-tracking data, in isolation and in combination with each other. We conduct a statistical analysis of classifier performance that provides insights into the effectiveness of the different data modalities in terms of predicting emotion pairs. Our analysis shows that combining data from different eye-trackers is feasible, and can be utilised for real-world affect detection.
Second, we look at predicting student learning performance using interface interaction data in a game-based OELE. Our work builds a data-informed intelligent pedagogical agent (IPA) leveraging interaction data in online classrooms and including expert insights that predicts students' future learning performance during self-directed interaction. Our work tests the effectiveness of these predictions to trigger help interventions for struggling students. To the best of our knowledge, we are the first to build and evaluate an IPA for in-the-wild interaction with OELEs. In this regard, our study provided empirical evidence for research in OELEs that adaptive scaffolding can improve student learning performance.
Last, we systematically evaluated various predictive classifiers across multiple open-learning datasets. Our analysis provides insights into the strengths and weaknesses of different classifiers along with a discussion about the tradeoff between inherent interpretability and accuracy. These findings aim to contribute to the development of more effective adaptive support systems and scaffold research on building personalized systems in learning.Science, Faculty ofComputer Science, Department ofGraduat
Decoding presenilin 1 mutations in Alzheimer’s disease : molecular, cellular, and behavioural signatures
No full textThe full abstract for this thesis is available in the body of the thesis, and will be available when the embargo expires.Medicine, Faculty ofGraduat
Designing for inclusive mental health : interactive technologies for storytelling, connection, and support
No full textMental health is an increasing concern on university campuses, but many students face significant barriers to seeking support, especially international students and those from minority backgrounds. Stigma, unfamiliar care models rooted in Western norms, and difficulty expressing distress often lead them to underutilize available campus services, reinforcing a broader culture of silence around mental health and contributing to worsening outcomes. In response, digital mental health technologies have been promoted as scalable and accessible alternatives, but many overlook the personal, cultural, and relational factors that shape how university students seek and experience mental health care.
This dissertation explores how the design of interactive systems can improve inclusivity, accessibility, and emotional engagement in mental health support for university students. Guided by a human-centered approach and the Design Thinking model, I explore these challenges across four studies. The first two studies use interviews and co-design with international and East Asian students to identify barriers to accessing support and to surface design opportunities that highlight self-help, social support, and professional guidance. These studies highlight storytelling as a promising approach to promoting mental well-being: by sharing and engaging with personal experiences, storytelling can dispel negative attitudes and foster a sense of community. The third study builds on this by introducing Digital Human Library, a storytelling platform that supports help-seeking self-efficacy through curated peer and professional narratives. The final study exploratively compares two writing assistant tools powered by large language models (LLMs), one that is emotionally expressive and one that is creatively structured, and analyzes how these two different types of artificial intelligence (AI) support can scaffold the writing of mental health stories intended for sharing. Chiefly, we look at therapeutic reflection, emotional engagement, and perceptions of authenticity from the perspectives of both writers and readers.
These studies contribute practical design strategies and theoretical insights for building inclusive mental health technologies. The dissertation also raises critical questions about the role of AI in therapeutic contexts, highlighting tensions around guidance, voice, and vulnerability in digitally mediated care.Science, Faculty ofComputer Science, Department ofGraduat
Growing plant love : park user perceptions of invasive plants in two parks of Kelowna, BC
No full textMany current discourses of invasive plant species as malicious promote campaigns of eradication (Lidström et al., 2016; Subramaniam, 2001). However, in the context of climate change and colonialism, native ranges of plants and other species have changed dramatically and will continue to do so; interdisciplinary research is urgently needed to rethink human interactions with local ecosystems, as all species (humans, plants, and others) will have to adapt to these changes together (Grenz, 2024). Using the framework of environmental humanities, this study investigated park user interactions with introduced/invasive plant species in two parks in Kelowna, BC, on unceded syilx territory. My master’s thesis asks: what perceptions do community members have of invasive plants and how can community-engaged methods offer local perspectives that might challenge, complement, or extend notions of invasive plants in conservation biology and related fields? Importantly, the goal of this thesis is not to comprehensively present or critique scientific perspectives on invasive plants. Rather, it trials methods for engaging local park users and presents their perspectives on these issues, in recognition that the success of plant management actions will be strengthened with local user input and engagement.
The study was split into three phases investigating Woodhaven and Mission Ridge parks spanning Jan. – Dec. 2024. Phase I: multispecies ethnographic observation using sketching, multimedia recording, notetaking and thick description methods. Phase II: community-engaged walking interviews with 8 participants in the two parks. Phase III: two community arts-based workshops (collaborative zine-making) to facilitate deeper, participatory, and collective exploration of these views. Arts-based methods allowed for building community trust and exploring latent perspectives. This thesis begins with an introduction to research on invasive species and critiques from Indigenous and environmental humanities scholars. The second chapter introduces the place this research was conducted (Kiʔláwnaʔ, on unceded syilx territory). Each body chapter takes its name from one plant encountered in this research – dandelion, Oregon grape, baby’s breath, great mullein, and tree of heaven – and explores issues that arose in relation to these species. I finish with a coda on future possibilities for how we could relate to introduced plants.Arts and Social Sciences, Irving K. Barber Faculty of (Okanagan)Graduat
Lasting pain in dairy calves
No full textPain during and immediately after routine husbandry procedures has been widely studied, and mitigation strategies have been developed. However, pain experienced during the healing period—lasting pain—remains poorly understood and under-assessed. The aim of this thesis was to develop methods for assessing lasting pain and, using these methods, evaluate strategies to mitigate it. Chapter 1 reviewed existing pain assessment techniques and evaluated their potential for detecting lasting pain. It also explored factors that may influence pain during the healing period. Chapter 2 investigated a memory test paradigm as a tool for assessing lasting pain following hot-iron disbudding. No differences in memory performance were found between disbudded and control calves, suggesting that this method may not reflect lasting pain. Chapter 3 explored behavioural indicators—short-term lying bouts and half-lying bouts—and memory improvement as potential markers of lasting pain following castration. Short-term lying bouts were more sensitive to acute pain than general lying behaviour, but no reliable indicators of lasting pain were identified. Chapter 4 shifted focus to pain mitigation strategies that do not rely on pain assessment. Specifically, it examined how hot-iron application time and tip size affect wound characteristics and healing. Larger tips produced larger wounds with longer healing times, while longer application times resulted in deeper and larger wounds but did not affect healing duration. I conclude that the memory test did not prove effective for assessing lasting pain, but that refining procedural factors—such as iron tip size and application time—can reduce healing time and potentially mitigate any resulting pain. This thesis highlights the need for more sensitive and reliable indicators of lasting pain and suggests that procedural refinement may offer a practical path forward.Land and Food Systems, Faculty ofGraduat