Digital Commons Network^™

Extraction And Separation Of Metal Cations From Synthetic Acidic Solutions Using Emulsion Liquid Membrane, Nouhaila Filali

Masters Theses

The work is organized into two main papers supported by experimental and comparative studies using Emulsion Liquid Membrane (ELM) systems. The first paper explores the individual extraction of heavy metals (Cd, Cr, As, Ni) from synthetic phosphoric acid using Alamine 336 and D2EHPA as carriers. Alamine 336 achieved the highest extraction efficiency (>90%) and stability, offering a promising route to reduce toxic impurities in fertilizer-grade acid. The second paper examines the selective separation of Ni2+ and Co2+ from various acidic solutions using the ELM configuration. Systematic variation of carriers, stripping agent and feed acidity, clarified transport mechanisms and stability, …

Testing The Life-History Dependence Of Dietary Restriction Effects On Oxidative Molecular Damage In Hornworms, Fahime Taheri

Masters Theses

DR and ambient temperature are two environmental factors widely implicated in shaping organismal maintenance and longevity through effects on metabolic rate and oxidative damage. This study tests whether DR and reduced body temperature independently or interactively reduce oxidative protein damage in the gut of tobacco hornworm larvae, a short-lived ectotherm whose life history may constrain typical DR responses. Larvae hatched from eggs were allocated to two feeding regimes (AL and DR) and to 20 °C and 30 °C. At a defined endpoint, guts dissected and homogenized, and analyzed for protein carbonyl content and total protein. Protein damage was expressed as …

Selective Surface Activation And Flotation Of Pyrite For The Recovery Of Tellurium From Sulfide Tailings, Mulenga Mutema Chibesa

Masters Theses

Copper sulfide tailings from past and present mining operations are important secondary sources of critical elements such as tellurium (Te), a key component in cadmium–telluride photovoltaic solar cells. Characterization of tailing streams from copper porphyry (CP) ore flotation revealed that Te-bearing minerals are predominantly hosted in pyrite, which is usually depressed and discarded. Enhancing pyrite recovery is therefore a critical first step toward concentrating Te minerals for downstream extraction. However, pyrite flotation is often hindered by hydrophilic surface complexes formed during prior processing. This research investigated selective flotation of Te-bearing pyrite from CP tailings using micro flotation and bench-scale flotation, …

Application Of Edge-Enhanced Phase Analysis To Active Microwave Thermographic Measurements, Douglas Blaine Fleetwood

Masters Theses

Nondestructive testing and evaluation (NDT&E) encompasses a range of inspection techniques that assess materials, components, and structures while maintaining their integrity and performance. Among these techniques, thermography is particularly attractive due to its non-contact imaging approach with easy-to-interpret results. Active Microwave Thermography (AMT) has emerged as a promising NDT&E inspection technique that utilizes electromagnetic energy to heat materials through dielectric and magnetic absorption, with subsequent infrared imaging used to detect subsurface defects. While AMT offers significant advantages including material-specific heating optimization and lower power requirements compared to conventional thermographic methods, the technique faces a persistent challenge related to the thermal …

Political Communication In A Multicultural Metropolis: Chinese Ethnic Media And The 2023 Toronto Mayoral By-Election, Dongwei Lin

Theses and Dissertations (Comprehensive)

Chinese are the second largest visible minority group in Canada and the most frequently reported ethnic or cultural origin in Toronto. Mandarin and Cantonese are, respectively, the largest and third largest non-official languages in Toronto. However, little research exists on the role of the Chinese ethnic community in Toronto municipal politics, especially the role of Chinese ethnic media in Toronto municipal elections.

The key argument of this thesis is that “Chinese ethnic media represent complementary public sphere(s) for informing and engaging Chinese Canadians in local political participation and discussion.” Through the 2023 Toronto Mayoral By-Election case study, this thesis examines …

Creativity, Fame And Power: A Critical Political Economy Of Social Media Comedy Skit In Nigeria, Idowu Badmus

Theses and Dissertations (Comprehensive)

This study explores social media comedy skits in Nigeria as a novel type of creativity that is both an economic and cultural activity with political and social implications within the context of the rapidly expanding global ecosystem of online content creation. Academic interest in social media comedy skits has grown as a result of their emergence as a popular culture within Nigeria's entertainment landscape. However, most research has focused on understanding this form of humour through its positive societal correlates. Hence, within the notion of industrialization of culture, which suggests that various methods of financing and arranging communication resources have …

Moral Identity: From Theory To Research, Jean Paul Lefebvre

Theses and Dissertations (Comprehensive)

Moral identity, often defined as the importance or centrality of moral values to a person’s sense of self, has long been understood to play an important role in moral functioning. However, critical gaps remain regarding its development, cross-context stability, and behavioural significance. This dissertation addresses these gaps in three empirical studies, providing new insights into the nature and function of moral identity across the lifespan and in daily life.

The first study (Chapter 2) explores developmental trends in moral identity, testing predictions from moral identity goal theory (Krettenauer, 2022). Using a cross-sectional sample spanning adolescence to old age, the study …

Art/Place Making In A Settler Colonial Context: A Critical Place Inquiry On The Haldimand Tract/Kitchener-Waterloo From A White Settler Perspective, Haley Sheppard

Theses and Dissertations (Comprehensive)

Although critical place scholars implicate artists in settler colonial processes of placemaking, there is little information on how white settler artists (WSAs) might use their creative practice to support practices of accountability and solidarity with Indigenous resurgence. This research responds to this gap by investigating the creative practices of WSAs located on the Haldimand Tract/in Kitchener-Waterloo (KW), and how they might approach critical, contextual practices in their creative work. A critical place inquiry was combined with ethnographic research principles and a transformative critical research paradigm. Six WSAs participated in mobile interviews, which took place in a location significant to them. …

Grief On The Margins: The Death Of A Family Member To Substance Use, Adair Shaw

Theses and Dissertations (Comprehensive)

Despite Canada's high death rates from substance use, there is limited research on the sociopsychological impact on families, who often face stigma and disenfranchised grief. This study explores how family members make meaning of a substance-related death. Through qualitative inquiry, eleven family members were interviewed on their experience of grief from substance death. The imprint of losing a family member to mental illness and substance use is fraught with intergenerational grief, ambiguity, prolonged mental-emotional distress, and relationship challenges. Substance death was also associated with stigma, social withdrawal, and shame for many participants. However, grievers reconstructed the socially prescribed negative perceptions …

Operationalizing Intersectionality Analysis For Urban Agriculture In Quito, Ecuador, Laine N. Young

Theses and Dissertations (Comprehensive)

This thesis outlines the results of a case study in Quito, Ecuador with the municipally led participatory urban agriculture project, AGRUPAR, an internationally recognized project that promotes women’s empowerment, traditional knowledge, agroecology, and livelihoods. It works to improve the lives of those experiencing high levels of poverty in Quito. This dissertation applies an intersectional analysis to urban agriculture research to enhance attention to power relations, social justice, and equity within its scholarly and practical realms. Intersectionality is an understanding that people have unique experiences of oppression based on their unique social location (what intersecting social categories they belong to) and …

Exploring Canadian Social Work Students' Aphobic Attitudes: The Role Of Knowledge About Asexuality And Asexual People, Brianna V. Azzoparde

Theses and Dissertations (Comprehensive)

Aphobic attitudes are negative biases and prejudices against asexual individuals that can contribute to aphobic discrimination. While the Canadian Social Work Code of Ethics states that social workers should not discriminate and should provide culturally responsive services to marginalized populations, individually held aphobic attitudes have the potential to diminish one’s ability to provide culturally responsive services to asexual people. This national study examined aphobic attitudes among 326 Canadian social work students, exploring the relationship between knowledge about asexuality and aphobic attitudes, including controlling for demographic factors, social contact with asexuals, and social attitudes that previous research has identified as being …

Contrasting Trajectories In Adolescent Pro-Environmentalism: Qualitative Differences Between “Engagers” And “Disengagers”, Jaida Brown

Theses and Dissertations (Comprehensive)

This qualitative study extends Krettenauer and colleagues' (2024) longitudinal research by examining how different developmental contexts shape divergent trajectories in adolescents' environmental engagement. We conducted semi-structured interviews with nineteen adolescents, focusing on two distinct groups: "Engagers" who showed remarkable increases in pro-environmental behavior from ages 13 to 17, and "Disengagers" who exhibited substantial decreases inengagement during the same period. While all participants reported meaningful childhood nature experiences, supportive family sustainability practices and access to environmental information through media, their developmental paths diverged significantly. Disengagers gradually deprioritized environmental concerns as other life goals took precedence, while Engagers actively expanded their environmental …

Inside The Circle 2025: Exploring The Ontario Cpe Supervisors' Lived Experience Of The Interpersonal Relations Group Process Portion Of Cpe, Kelly L. Collins

Theses and Dissertations (Comprehensive)

This research used a philosophical phenomenological (primarily Gadamer) methodology and asked the question, “What is the lived experience of Ontario Clinical Psychospiritual Education (CPE) Supervisors in the Interpersonal Relationships (IPR) group process portion of CPE?” It used a 90-minute, semi-structured interview format as it sought to understand the supervisor experience of safety in the group. 11 Ontario Certified Supervisors were interviewed and explored this question in relationship to participant supervisors’ experience as students and/or as educators. In the history of CPE, there has been significant harm done to students by some supervisors who were well-meaning, but unaware of their impact …

Examining Gender Differences In Heritage Language Maintenance And Loss Among South Asian First-Generation Canadians, And The Effect On Well-Being, Amreen Sangha

Theses and Dissertations (Comprehensive)

Language is prevalent in various aspects of life. Not only is it often essential for communication, but it also has deep roots within cultural contexts. Specifically, within South Asian culture knowing one’s heritage language is considered to be necessary when it comes to connecting with one's cultural group and identity. Heritage language maintenance can be seen differently within different individuals and have different implications for them. This study was designed to explore gender differences in heritage language loss as well as the role language may play in one’s well-being. Canadian-born South Asian children and young adults aged 10-25 completed an …

Examining The Impact Of Early Literacy Interventions On Teachers’ And Parents’ Learning And Perceptions Of Early Literacy Development, Abigael Mary Hogarth Todd Miss

Theses and Dissertations (Comprehensive)

Parents and teachers play a vital role in fostering early literacy development; however, many require additional training to enhance their understanding of alphabet knowledge and phonological awareness. This study examined the effectiveness of two instructional videos—one on phonological awareness and one on evaluating alphabet books—in increasing teachers’ (n = 35) and parents’ (n = 34) perceptions about these domains and the practical application of information covered in the videos. The 69 participants viewed each video, and results indicated a general decrease in confidence following exposure to these videos, likely reflecting an increased awareness of the complexity of the …

The Perceived Frequency And Effects Of Multilingual Communication In Youth And Adolescent Soccer, Simao M. Araujo

Theses and Dissertations (Comprehensive)

In professional soccer, the topic of multilingual communication has been widely researched; however, there appears to be a gap in the literature concerning how multilingual use is perceived by athletes and coaches at the youth and adolescent level of the sport. In the present study, male soccer athletes ages 10 to 18 years old and their coaches completed a questionnaire in which they rated both perceived frequency of use and perceived effects of using multilingual communication in youth and adolescent soccer. Specifically, these questionnaires elicited quantitative information regarding categories such as tactical advantages, words of encouragement, general expressions, and group …

Development Of A Stress Response Framework For Understanding Sogie Refugee Health, Arooran Saravanan Ananthavel Murugan

Theses and Dissertations (Comprehensive)

As an increasing number of individuals flee persecution on the basis of sexual orientation and gender identity expression (SOGIE), Canada has become a prominent destination for SOGIE refugees. The chronic stressors encountered by this marginalized population remain insufficiently studied, particularly in relation to physical health outcomes. This qualitative study investigates the cumulative health impacts of chronic stress among SOGIE refugees through the application of a cell-to-society framework, underpinned by Minority Stress Theory (MST). The study seeks to develop a SOGIE-specific stress response framework that theorizes the processes by which social and environmental stressors become biologically embedded, thereby contributing to elevated …

Negotiated Cultural Identity And Belonging Of Self-Identified Indo-Guyanese Immigrant Women, Neta (Goomatee) Deonarain-Gear

Theses and Dissertations (Comprehensive)

This dissertation examines how young, self-identified Indo-Guyanese women who immigrated to Southwestern Ontario in the 1970s negotiate cultural identity and belonging. Utilizing a bio-ethnographic bricolage narrative methodology, the study explores the impact of postcolonial diaspora and social displacement on these women’s experiences within the "third space" or borderlands. Grounded in relativist ontology and constructivist epistemology, storytelling serves as the primary data collection method through a critical theory lens. Interviews with 12 participants were analyzed thematically and reflexively, revealing how participants construct meaning and navigate cultural identities. The analysis, conducted through feminist, decolonial, and trauma-informed perspectives, offers insights into "psychological homelessness" …

Technology-Enhanced Professional Development For Early Literacy: A Comparative Study Of Online Teacher Learning Models In Kenya, Constanza Uribe-Banda

Theses and Dissertations (Comprehensive)

Growing recognition of early literacy as essential for lifelong learning, along with evidence that teachers’ mastery of foundational literacy instruction influences student outcomes (Darling-Hammond et al., 2017; UNESCO, 2020), has led to increased investment in teacher professional development. Despite these efforts, many educators face significant challenges in accessing high-quality training, particularly in resource-constrained settings where geographical barriers and limited institutional support persist. This is especially true in rural Kenyan communities, where teachers often work in under-resourced schools with unreliable electricity and internet connectivity yet bear responsibility for laying critical literacy foundations. The present study examines the potential to deliver effective …

Evaluating The Credibility Of Online Websites: A Digital Information Literacy Program, Emily C. Wood, Kim P. Roberts

Theses and Dissertations (Comprehensive)

The plethora of information currently available via the internet is greater than ever before. Given this, finding credible information is an exceedingly complex task for any information consumer, but especially so for children. Research shows that children have difficulty evaluating the credibility of online information and are more susceptible to believing misinformation compared to adolescents. While a growing body of research addresses children’s internet use, most research focuses on technology safety rather than the evaluation of online information. Several studies have found digital information literacy (DIL) interventions to be successful at increasing critical thinking and awareness of the criteria to …

Exploring The Experiences Of Racialized Immigrant Mothers In Contributing To Patterns Of Community Life In The Victoria Hills Neighbourhood, Carmel Tatiana Mahdi Miss

Theses and Dissertations (Comprehensive)

The experiences of racialized immigrant mothers are complex, nuanced, and beautiful. Oftentimes, their stories are described in a way that frames women as helpless victims, merely writing about their challenges in the absence of their protagonism. The stories in this thesis suggest that, against the obstacles unique to racialization, motherhood and immigration, mothers are often the primary caretakers of their families and play a significant role in the development of children, while creatively exploring and responding to questions pertinent to community development. They navigate community life in a place different from the one they grew up in – addressing questions …

Optical Detection Of Instantaneous Microwave Frequency And Displacement, Behzad Boroomandisorkhabi

Doctoral Dissertations

Research presented in this research is focused on developing and implementing novel photonic systems for instantaneous microwave frequency and displacement measurement, emphasizing cost-effectiveness, scalability, and high resolution. The research is encapsulated in three core studies: the design of all-fiber ultrafast ranging Lidar for medical motion management, the application of dispersive interferometry using picosecond laser pulses for laser ranging, and the integration of microwave photonic systems with digital signal processing (DSP) for enhanced measurement precision.

The work achieves micrometer-scale displacement accuracy and microwave frequency resolutions within ±1 MHz across wide dynamic ranges by leveraging dispersive interferometry and time-stretch techniques. The studies …

Design Of Real-Time And Energy-Efficient Driver Assist Systems Using Electroencephalogram And Neuromorphic Computing, Nathan Alan Lutes

Doctoral Dissertations

Despite the technological breakthroughs in advanced driver assist systems, distracted driving persists as a major challenge to roadway safety. This investigation advances the body of knowledge towards a solution by developing an individualized driver-state detection method using electroencephalogram (EEG) and neuromorphic computing to provide a less invasive and more energy efficient ADAS solution. It furthermore explores the changes in brain functional connectivity under distracted conditions to better understand brain state information that could be used for neuro-feedback intervention systems. The first contribution introduces the concept of using Convolutional Spiking Neural Networks (CSNNs) for recognition of patterns with movement-intention predictive power …

Synthesis And Analysis Of Materials For Quantum Devices, Mathew Pollard

Doctoral Dissertations

Quantum materials play a pivotal role in the advancement of next-generation technology. Superconducting quantum computing, dissipationless spintronics, or valleytronics offer promising ways forward beyond traditional chip miniaturization. Josephson Junctions (JJs) have already revolutionized quantum information and high precision detectors. Quantum systems, however, are either hard to control, produce, and/or maintain. This calls for a better understanding of microscopic properties and tuning of these quantum states.

In this work, we experimentally investigated growth methods to control the electric and magnetic properties of Topological Insulator (TI) Sb2Te3 through Cr-doping. Our results demonstrate the onset of a Magnetic Topological Insulator (MTI) and have …

Higher-Order Statistics And Normalized Decay Analysis For Detector Deadtime Characterization, Abdallah Wazzan

Doctoral Dissertations

Detector deadtime limits radiation measurement accuracy at high count rates, yet current methods rely on idealized paralyzable or non-paralyzable models. Real detectors exhibit hybrid behavior requiring advanced characterization approaches. This study explores deadtime characterization using two Monte Carlo simulation approaches: higher-order statistical analysis of inter-arrival times and simplified deadtime correction with hybrid models.

Using MATLAB (PULSE-WIZ), we analyzed full decay curves spanning ~4.5 half-lives of Cobalt-60 and Vanadium-52, examining coefficient of variation (CV), skewness, and kurtosis of inter-arrival times, plus normalized decay curves with Full Width at Half Maximum (FWHM) analysis. Hybrid models incorporated paralyzable and non-paralyzable components with dead …

Tailoring Selected Aerogels To Targeted Applications, Stephen Yaw Owusu

Doctoral Dissertations

Aerogels are ultra-lightweight, porous solid materials characterized by a three-dimensional nanostructured network. Owing to their exceptional physical and chemical properties, aerogels have garnered considerable attention within the materials science community and were recognized by IUPAC in 2022 as one of the top ten emerging technologies in chemistry. Although numerous aerogels have been synthesized, only a few have been effectively tailored for specific applications. Optimizing the properties of known aerogels for targeted uses remains challenging. This dissertation investigates strategies for tailoring aerogels derived from isocyanate-benzoxazine, benzodiazine, and phenolic resins to meet the requirements of various advanced applications. The approaches employed include …

Characterization And Deportment Of Anode Impurities In Copper Electrorefining, Charles Michael Campbell

Doctoral Dissertations

The objective of this research was to study the deportment of the group 15 elements, arsenic, antimony and bismuth during copper electrorefining. Samples were collected from six industrial copper anodes with different compositions. Specimens were physically characterized and electro refined to understand the differences in the behavior of selected impurities. Inclusions in the cast metal structures were characterized using automated scanning electron microscopy and energy dispersive spectroscopy to measure and correlate their size, shape and composition. Arsenic and lead were found to have a positive correlation between concentration and size of inclusions. Using wavelength dispersive spectroscopy, multiphase inclusions were examined, …

Machine Learning Models For Location Prediction, Message Routing And Path Planning For Rescue Of Underground Miners, Abhay Goyal

Doctoral Dissertations

Self-rescue during underground mine disasters is vital for miner safety. Evolving hazards and post-disaster conditions demand solutions that enable navigation under severe communication and computational constraints. Centralized systems often fail in such rugged settings, while decentralized methods—particularly Delay Tolerant Networks (DTNs), proven in battlefields and space missions—offer distinct advantages for underground applications. This research addresses five core challenges: (i) predicting miners’ next locations on low-power devices using points of interest and movement sequences; (ii) delivering timely updates on safe routes, evacuation zones, and hazardous areas; (iii) evaluating energy efficiency and comparing graph-based approaches to existing methods; (iv) enabling edge-ready frameworks, …

Process-Structure-Property Relationships In Laser Powder Bed Fusion Produced 17-4 Ph Steel, Ben Brown

Doctoral Dissertations

Laser powder bed fusion (LPBF) is a metal additive manufacturing method that produces non-traditional microstructures as a result of the rapid solidification and thermal cycling inherent to the process. When using LPBF-produced material in application, these unique microstructures challenge the applicability of well-developed mechanical property databases achieved by conventional heat treatments. For wider adoption of this technology, a more holistic understanding is necessary on how process attributes develop material structure, which dictate mechanical properties. This dissertation explores the process structure-property relationships in LPBF 17-4 PH steel through systematic evaluation of atmospheric processing and heat treatment effects on microstructure and mechanical …

Generalizations Of Finiteness Conditions And Extension Monads In Algebras With Infinitely Many Or Infinitary Operations, Danielle Christienne Bowerman

Doctoral Dissertations

In this work, we extend the results of finiteness conditions and extension monads found in Insall from finitely many finitary operations to infinitely many finitary operations, as well as touching on infinitary operations. We also examine varieties of algebras, including the notion of strong varieties introduced in Insall, and common constructions of extension monads in varieties of algebras. We see that for finite collections of algebras of the same signature, the extension monad operation on a variety of algebras commutes with the direct product operation, and all retractions from an enlargement or extension monad are trivial. We also see that …