title: Virtutello: Balancing Physical and Digital Interaction in a  Mixed Reality Sculpting Tool

contributor:
Graham, Nicholas
Computing

subject:
Mixed reality
Digital sculpting
Human Computer Interaction

abstract:
Sculpture is an art form dating back over millennia. More recently, 3D digital sculptures are used in video games, movies, and manufacturing. Traditionally, sculptors have used their hands and tools to shape wood, clay, stone or metal into an art piece. Currently, digital sculpting is accomplished using two dimensional flat screens, mice and keyboards. In this thesis, our goal is to understand how best to combine traditional and digital sculpting interaction techniques. We developed a mixed reality sculpting tool, Virtutello, which allows us to explore this question.  Virtutello allows the user to use their hands to point and sculpt within a mixed virtual digital environment. As well, the user can physically move around the sculpture to see it from different perspectives. In an observational study of 20 participants, we found that users could be trained within thirty minutes and had a moderate degree of success in completing basic sculpting tasks.
We focused our investigation on three main research questions. First, a core of sculpting is the ability to touch and select areas of a sculpture. We investigate the success of two pointing techniques, the novel open-hand pointing and the traditional finger pointing. We found there is an advantage using open hand pointing while sculpting in a mixed reality application. Participants completed tasks faster and with a higher degree of success when using open-hand pointing. Participants also expressed they felt more in control and had less of a challenge while completing tasks using open-hand pointing. Second, operating in a virtual world allows the user to physically move around the sculpture. We investigate whether there is a cost to sculpting while standing versus sitting, finding there is no cost to accuracy and task completion time. Third, we investigated user’s behavior when given this freedom to physically move around the sculpture.
We found that participants preferred to remain stationary while sculpting, regardless of whether they were sitting or standing. Instead of moving around to change their perspective, participants preferred to rotate the sculpture digitally in front of them.

abstract: M.Sc.


title: Nonlinear Adaptive Droop Control Method for the Battery Storage Systems Operating in DC Microgrids

contributor:
Bakhshai, Alireza
Eren, Suzan
Electrical and Computer Engineering

rights: Queen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canada

rights: ProQuest PhD and Master's Theses International Dissemination Agreement

rights: Intellectual Property Guidelines at Queen's University

rights: This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.

subject:
Power Electronics
DC/DC Converters
DC Microgrids
Battery Storage Systems
Droop Control system

abstract: Conventional sources of energy like coal, gas, and oil are being depleted and renewable sources of energy are needed to meet ever-increasing energy demands. Renewable Energy Sources (RESs) like solar and wind can be potentially harnessed, however, high penetration of the RESs will introduce new challenges for the safe operation and control of future grids. To solve this problem, microgrids (MG) can be used to coordinate distributed energy resources in a decentralized fashion in order to ensure the reliability and efficiency of the local distribution network. Recently, there has been a great increase in the number of DC sources and loads leading to a need to develop DC MGs, which are more efficient and less costly. Despite the benefits of DC MGs, there are some challenges that need to be addressed in order to take full advantage of DC MGs and ensure the safe operation of the system under all operating conditions. This thesis proposes a decentralized control solution for energy storage systems (ESSs) in islanded DC MGs, namely a nonlinear adaptive droop controller. In the islanded mode of operation, the tight regulation of the DC-bus voltage is very challenging. The proposed decentralized control technique utilizes a nonlinear adaptive droop profile with adaptive parameters, which are able to regulate the DC-bus voltage tightly during various changes in loads/sources within a DC MG. The proposed controller does not need to identify between the charge and discharge operation modes. The adaptive control parameters can be determined by using three different strategies. In the first strategy, only one of two adaptive parameters in each mode of operation (charge and discharge modes) is unknown, which is determined from a look-up table. In the second strategy, a nonlinear Sequential Quadratic Programming (SQP) optimization technique is employed to derive the adaptive parameters. The proposed technique adaptively regulates the controller parameters according to the battery’s SoC and the DC MG voltage. In the third strategy, the fast charge and discharge voltages are assumed to be known. In this approach another droop controller, which is called the speed-droop controller derives the unknown parameters. The stability of the proposed control schemes is proven in this thesis, and the validity of the proposed schemes is proven through simulation and experimental results.

abstract: M.Sc.


title: Coping with Thermal Challenges: Reaction Norms of Life History Traits of a Burying Beetles with Biparental Care

contributor:
Bonier, Frances
Biology

rights: Attribution-NonCommercial-NoDerivs 3.0 United States

subject:
Thermal Ecology
Phenotypic Plasticity
Life History
Reaction Norms
Burying Beetles
Parental Care

abstract: To succeed and thrive in different environments, individuals can express plastic phenotypes, including life history traits, to ensure some level of fitness across conditions. As such, the plasticity of traits is central to understanding how individuals cope with the challenges associated with variable environmental conditions. Previous work has described how several traits relevant to fitness respond to different temperatures, but much of this work has focused on only one or a few traits and overlooked interactions between traits. Few have considered the effects of temperature on parental care – a highly flexible trait that can have important effects on fitness and might buffer offspring from environmental challenges. Here, we investigated the plasticity of life history traits, including parental care, in the burying beetle Nicrophorus orbicollis, which exbibits biparental care. We took an integrative approach to study how organisms cope with temperature variation. We conducted a captive experiment to characterize the family-level reaction norms of several life history traits across temperatures. We found that life history traits showed varying levels of plasticity, and some traits exhibited family-level variation in reaction norms, which might reflect underlying heritable variation in plasticity. We also found that parental care buffered some but not all effects of temperature on fitness in N. orbicollis. Contrary to expectations, offspring size did not change across temperatures. Our findings suggest that N. orbicollis cope with challenging warmer temperatures by reducing brood size to provide higher levels of care per larva such that offspring eclose at a similar size regardless of temperature. Taken together, our results show that life history responses to different temperatures reflect the incorporation of several reaction norms, which vary among families and have important fitness consequences.

abstract: M.Sc.


title: Monocouches auto-assemblées et nanostructures de métaux nobles : préparation et application au photovoltaïque

contributor:
Nunzi, Jean-Michel
Patrone, Lionel
Chemistry

subject: argent

subject: ATR-FTIR

subject: humidité relative (RH)

subject: monocouche auto-assemblée (SAM)

subject: nanostructure

subject: Pentacène

subject: photovoltaïque organique (OPV)

subject: PTCDI-C5

subject: Raman

abstract: Au cours de ce travail, dans une première approche descendante, nous avons étudié la réalisation de cellules solaires multicouches évaporées à base de matériaux organiques : le pentacène et le PTCDI-C5. Nous nous somme servis de cela pour bâtir des cellules simple jonction bicouches et les caractériser. Ces cellules ont servi de modèle de référence à notre étude et démontrent des capacités en accord avec la littérature. Nous avons ensuite produit et caractérisé des cellules multijonctions en bicouches. Une rapide étude sur le comportement d’une couche d’argent d’épaisseur nanométrique a servi à déposer la couche de recombinaison de ces cellules. Nous nous sommes ensuite attelés à la réalisation de monocouches auto-assemblées sur silicium dans le but de développer des couches actives donneur-accepteur et de pouvoir les empiler par l’approche ascendante. Après avoir étudié les groupements d’accroche silanes et acide phosphoniques, nous avons investigué la réalisation de SAM de  (3-Triméthoxysilylpropyl) diéthylènetriamine (DETAS) sur silicium en tant que d’accroche pour les molécules actives. Nous avons mis en évidence la présence de liaisons hydrogènes aidant à l’organisation de la SAM grâce à des analyse ATR-FTIR. Nous nous sommes servis de cette SAM comme couche d’accroche pour la greffe une molécule photo-active le pérylène tétracarboxylique dianhydride (PTCDA). Les techniques de caractérisation par AFM, ellipsométrie et spectroscopie Raman nous ont servi à caractériser notre surface après la greffe de PTCDA.

abstract: PhD


title: Recruitment Algorithms for Vehicular Crowdsensing Networks

contributor:
Choudhury, Salimur
Salomaa, Kai
Akl, Selim
Computing

subject:
Crowdsensing
Public sensing

abstract: Vehicular crowdsensing aims to utilize the plethora of onboard sensors and resources on smart vehicles to gather sensing data in a large coverage area. Due to vehicles’ predictable mobility, roadside service providers can use vehicles’ announced trajectories to recruit vehicles to provide sensing data for a coverage area. Existing works have utilized optimization models to obtain optimal solutions. Heuristic recruitment algorithms aim to obtain an approximate solution which runs in polynomial time. In this thesis, we propose several heuristic recruitment algorithms for a variety of vehicular crowdsensing problem formulations. We first explore the temporal vehicle recruitment problem where we recruit vehicles all travelling in the same direction on one road over time. We propose a heuristic recruitment algorithm to compare to an existing optimal framework and heuristic, and achieve better coverage at lower recruitment costs than the existing heuristic. We also prove that the existing heuristic can be arbitrarily bad in the worst case. We then consider the spatiotemporal vehicular recruitment problem where we recruit from vehicles moving freely in a two dimensional space. We propose a new optimal framework for obtaining optimal solutions, as well as a heuristic which we compare to an existing heuristic. Our performance evaluations show that we outperform the existing heuristic in terms of recruiter utility as well as recruitment cost. We also propose a new variation of the vehicular recruitment problem that considers a two dimensional coverage area with certain subsets of area having increased priority. We propose both an optimal model as well as a heuristic for obtaining approximate solutions, which in our performance evaluations on small numbers of vehicles, achieves coverage near optimal at only slightly more expensive recruitment costs. Finally, we consider the heterogeneous or multi sensor vehicular recruitment problem, where vehicles have multiple sensor types and areas of coverage require a certain sensor type to be covered. We propose an optimal model and heuristic for this problem, and again show in performance evaluations that the heuristic returns solutions close to optimal in scenarios with small numbers of vehicles.

abstract: M.Sc.


title: Characterizing the Role of the RET Receptor Tyrosine Kinase in Colorectal Cancer

contributor:
Mulligan, Lois
Pathology and Molecular Medicine

subject:
Cancer
Cell Signaling
Colorectal

abstract: RET is a receptor tyrosine kinase (RTK) that plays important roles in both normal development and cancer. RET has well-established oncogenic roles in thyroid cancer and growing evidence implicates RET activity in the development and progression of other tumor types, including pancreatic and breast cancer. RET is activated by interacting with its ligand, a member of the GDNF family, and a co-receptor, a member of the GFRα family. This tri-molecular complex activates RET-mediated downstream signaling pathways which promote a variety of cellular processes, including proliferation, migration, and survival. RTK-mediated activation of these pathways is an established method of colorectal cancer (CRC) development and progression to a metastatic phenotype. RET expression has been identified in CRC, however its role in this disease remains unclear. Here, we investigated the effects of RET activity in CRC. We first developed a novel in vitro method for generating and using 3D cell spheroids as a more physiologically representative assessment of cell behaviour compared to traditional 2D methodologies. We subsequently used this model in our study of RET-mediated CRC progression. We showed that RET activity in CRC cells promotes a more mesenchymal-like phenotype, and enhances cell proliferation, migration, and 3D invasion. We also assessed RET expression in two CRC patient cohorts. RET expression was correlated with malignancy and poor patient prognosis. Together, our data suggest an oncogenic role for RET in CRC which may be of future interest as a potential therapeutic target.

abstract: M.Sc.


contributor:
Miller, James
Cultural Studies

subject:
New Materialism
Affect Theory
Chinese Buddhism
Religious Studies
Incense
Shanghai

abstract: Incense has been an integral part of Chinese culture since before the introduction of Buddhism in the third century B.C.E. A rise in the popularity of Buddhist practice marked an increase in the importation, production, and use of incense in China. Incense was used for everything from acting as an aid in the most mundane activities, like telling time, to accomplishing the most extraordinary activities, like helping Buddhist practitioners achieve instant enlightenment. Yet, despite incense being a seemingly integral part of Chinese history and culture the government has created a policy limiting the use of incense in Buddhist temples. “Tracing Incense: The Affective Power of Objects” asks the question: what can be gained by introducing new materialism and affect theory to religious studies research? Specifically, how can embodied, sensory observations of incense in four Buddhist temples in Shanghai enrich our understanding of contemporary Chinese Buddhism? There is scholarship discussing the role of material objects in religion, as well as scholarship introducing affect theory to religious studies but there is little to no writing that brings religious studies into conversation with both new materialism and affect theory to investigate what each theoretical model lends to the other and to the greater study of religion. To illustrate how material and affect based research can be helpful in developing the field of religious studies, I will share my observations of incense in four Buddhist temples in Shanghai that I gathered while conducting sound and smellwalks. I will analyze my data using concepts from new materialism and affect theory. I will move past my observations to think about the socio-political entanglements that incense, and Chinese Buddhism are enmeshed in. I will argue that the limitation of the use of incense in Buddhist temples in an effort to control, monitor, and reduce religious practices. “Tracing Incense: The Affective Power of Objects” will conclude by arguing that introducing new materialism and affect theory to religious studies offers new and exciting ways of learning about the complexities of lived traditions.

abstract: M.A.


title: Investigating Subsurface Flow Delivery to a Small High Arctic River

subject:
Subsurface Flow
Permafrost
Hydrology
Preferential Flow Pathways

abstract:
Preferential flow pathways and hydraulic gradients along the hillslope-floodplain-channel continuum are dominant controls on the delivery of baseflow, stormflow and solutes to channels in temperate systems. Arctic systems are increasingly being shown to possess similar delivery mechanisms, however the topic is understudied, acutely so in the High Arctic. This work assesses the nature of delivery mechanisms in the High Arctic over the thaw season and in response to rainfall at the Cape Bounty Arctic Watershed Observatory (CBAWO). Two locations of persistent preferential subsurface inputs were observed over a 200 m section the study reach, one at the outlet of a previously active channel through the floodplain, and another at the outlet of a channelized sub-catchment. During baseflow, these inputs provided solute-rich, relatively cold water to streamflow. During stormflow, subsurface inputs remain active and in the case of the sub-catchment, there was evidence for increased flux of pre-event soil water. Over the 320 m study reach, heterogeneity in the nature of hydraulic gradients, in how gradients developed over the season, and in how gradients responded to rainfall was observed. Two monitored hydraulic gradients exhibited reversal of inferred flow direction; one due to rainfall and the other as the thaw season progressed.

Economic feasibility of hydrological investigations concerning total dissolved solids and electrical conductivity (EC) becomes an issue when spatial and temporal scales increase, especially when the objective is to capture the variability inherent within aquatic systems. Chapin et al. (2014) presented a modified version of the Onset HOBO Pendant waterproof temperature and light logger with the ability to assess relative EC, however it was not dimensional EC (i.e. µS/cm). This work demonstrates these economical loggers can be calibrated and applied to quantify EC in the field with accuracies comparable to commercial loggers.

abstract: M.Sc.


title: Disengaged and Disenchanted Adolescents: An Arts-Based Case Study

contributor:
Eyers, Kimberly
Education

subject:
Adolescents
Secondary School
Arts-Based
Poetry
Visual Art
Drop Out
At-Risk

abstract: The pursuit of creating valuable learning experiences for adolescents is a complex challenge. The purpose of this study is to explore the experiences of a group of disengaged and disenchanted adolescents. I identified a gap in the literature; youth are often only quoted for comments affirming that interventions have been beneficial. The present study seeks to fill this gap by representing as directly as possible the experiences of participants that relate to their motivation and engagement. To investigate the processes at work that contribute to the general decline in motivation that occurs in early adolescence (Gottfried, Flemming & Gottfried, 2001; Harter, 1981; Whitlock, 2006), and that for some result in definitive disengagement with formal education, I used art elicitation to facilitate the communication of various experiences of school by one group of urban self-identified disengaged and disenchanted adolescents. The data were analyzed using traditional qualitative methods, as well as poetic inquiry, which offers aesthetic representations of reflexive research methods and meditations on significant themes and topics in the data. The visual and written data provide rich information about contemporary experiences of secondary school for the disengaged and disenchanted adolescent participants and inform a discussion of recommendations and personal discoveries.

abstract: M.Ed.


title: Damage Threshold of Near-Cross-Ply and Angle-Ply Tubes Used in Concrete Filled FRP Tubes Loaded in Flexure

contributor:
Fam, Amir
Civil Engineering

subject:
concrete-filled
FRP tube
damage
cut
section loss
flexure

abstract: Concrete-filled fibre-reinforced polymer (FRP) tubes (CFFTs) have been studied extensively, but a lingering question remains regarding the vulnerability of the exposed tube to accidental damage or vandalism.  In this thesis, the effect of damage induced in the tubes on the flexural strength of CFFTs is studied. Two commonly available types of tubes are explored, one with near-cross-ply having nearly orthogonal fibre arrangements, and one with large (±55°) angle-ply fibre arrangements. Eighteen CFFTs using the former tube and twelve CFFTs using the latter tube were tested in four-point bending, including undamaged control specimens to establish their full nominal strength (Mno). Full wall thickness cuts were introduced in the glass-FRP tubes in the circumferential and longitudinal directions, on both the tension and compression sides.  The cuts also varied in length, as a ratio of the outer perimeter πD, and their proximity to neutral axis was varied for one type of tubes.  It is shown that the most critical cut for both tubes is the circumferential one on extreme tension side. The reduced-to-control ultimate moment ratio (Mn/Mno) of the angle-ply CFFTs reduces almost linearly from 1.0 to 0.36 as the cut length increases from zero to 20% (πD). This is much less critical than in near-cross-ply CFFTs, where (Mn/Mno) drops sharply from 1.0 to 0.55 at a 2% (πD) cut, then gradually to 0.25 at a 20% (πD) cut. The maximum difference between angle-ply and near-cross-ply CFFTs seems to occur around the 10% (πD) cut, where (Mn/Mno) ratio of the near-cross-ply CFFT is only half that of angle-ply CFFT. As the location of a 3% (πD) circumferential cut shifted from extreme tension to an 80° angular location from the bottom of a near-cross-ply CFFT, (Mn/Mno) increased from 0.52 to 1.0. Longitudinal tension cuts caused (Mn/Mno) to drop linearly from 1.0 to 0.47 at a 22% (πD) cut length, which was similar for both tubes.  Compression side longitudinal and circumferential cuts were less critical with (Mn/Mno) being 0.8 to 0.9. For practical design purposes, a case study based on ultimate static strength showed that CFFTs similar to the ones tested in this study can tolerate a circumferential tension cut up to 30% (πD), for both tube types, before they have to be taken out of service or repaired.

abstract: M.A.Sc.


title: Design of Nanostructured Nickel Hydroxide-based Materials for Renewable, Electrochemical Energy Applications

contributor:
Jerkiewicz, Gregory
Chemistry

subject:
Chemistry
Electrochemistry
Nanomaterials
Energy
Nickel Hydroxide
Layered Double Hydroxide
Mesoporous Metal Oxide
Nickel

abstract: This contribution investigates the synthesis and characterization of nickel and nickel hydroxide-based materials with intended applications as electrode materials and electrocatalysts in clean, renewable energy technologies. A diverse range of nickel-based nanostructures are studied to identify candidates with high surface area and significant electrocatalytic activities towards the relevant hydrogen and oxygen redox reactions. The structures studied in this work include nickel hydroxide nanocages, nickel-based layered double hydroxide (LDH) nanoparticles, and nickel-based mesoporous metal oxides (MMO). To evaluate these materials, a complete characterization of the synthesized nanostructures is presented, comprising a combination of thermal analyses, surface science techniques and electrochemical analyses to gain a fundamental understanding of their chemical composition and structural features. Based on these results, we propose a tunable methodology for the preparation of nickel-based LDH nanoparticles including various historically relevant, hybrid nickel materials (i.e. Ni-Al, Ni-Zn, Ni-Fe, etc.). Tripodal ligands are applied in this technique to act as particle growth control agents, resulting in the successful isolation of nanoparticles as small as 30 nm and 15 nm (diameter), in the cases of Ni and Ni-Fe, respectively. Assembly of these nanoparticles into larger mesoporous structures was also performed using a soft polymer-templating method, and a comprehensive overview of this technique is presented. Successful conversion of hybrid nickel hydroxide nanoparticles to the corresponding mesoporous nickel oxide was confirmed by electron microscopy and electrochemical measurements. The foundation for further exploration of a vast series of nickel hydroxide and nickel oxide functional nanomaterials is established based on the novel research presented in this work.

abstract: M.Sc.


title: Communicating Places, Ideas, and Canadian Identity In A Changing World: A Social Biography of Thomas Clarence Cummings, 1904-1996.

contributor:
Osborne, Brian
Schwartz, Joan
Geography and Planning

subject:
Thomas Clarence Cummings
TC Cummings
Modernity
Canadian Identity

abstract: Other than at his birthplace in Pittsburgh Township, Ontario, and his lived-in community of North Bay, Ontario, Thomas Clarence Cummings (T.C.) is a relatively unknown presence in the collectivity of those who have contributed to the representation of Canadian identity at the community, regional, and national levels. Cummings left us a prolific number of statements in several media communicating how he perceived who we were as Canadians in the twentieth century. These are examined through an analysis of several stages in T.C.’s “life-path”: as a youngster on a farm in Pittsburgh Township and as a student in a one-room schoolhouse on Woodburn Road; as a young man in North Bay pursuing a career in education and the initiation of a life-long commitment to international travel; as a volunteer in World War II serving in Atlantic Canada; on his return to teach in North Bay and the resumption of his travels worldwide; as a retired teacher, an active artist, and social critic producing reflexive commentaries on society in a modern and post-modern world. In particular, Cummings’ journals, poems, and artwork are connected to his travels and his commentaries about our evolving Canadian identity and our relationship with a global society. His later allegorical paintings, poetry, and writings expressed his assessment of how Canadian society was being affected by modernity and globalization during his life-time. This thesis examines Cummings’ various messages to demonstrate his appreciation of the complexity of the social landscape in his time, and concludes with an assessment of the significance of his contributions in the context of current priorities and concerns in Canadian society today.

abstract: PhD


title: Computer-Integrated Methods for Breast Cancer Surgery and Brachytherapy Guidance

contributor:
Fichtinger, Gabor
Computing

subject:
breast conserving surgery
breast conserving therapy
breast cancer
lumpectomy
brachytherapy
breast brachytherapy
navigated lumpectomy
navigated brachytherapy
computer assisted surgery
tracking

abstract:
Breast cancer is a leading cause of cancer-related death in women in Canada. Lumpectomy and brachytherapy are treatments of choice for early stage breast cancer, but the soft nature of the breast makes it difficult to deliver accurate treatment to the intended sites. Navigation systems offer improved accuracy, reduced cost, and reduced time requirement. Unfortunately navigation systems are still limited because anatomy can move relative to the body. This thesis makes three contributions to this area.

In navigated lumpectomy, the tumour is tracked rigidly relative to a tracked needle. However, no rigid relationship exists and the needle can spin in place around the tumour, resulting in erroneous tracking. I propose a method to isolate different types of change in position and orientation, then apply it to computationally compensate for lack of a physical rotation constraint. A phantom study shows that this method improved tumour tracking by 15\% of its volume over the existing method. Fewer degrees of freedom are required, enabling smaller and more affordable hardware to be used.

Navigated lumpectomy can rely on a technician's presence. This contributes to cost and crowding in the operating room. I propose to reduce reliance on the technician by delegating display-related tasks to a computer. Two methods are discussed - one to allow the surgeon to point an instrument to create their desired view, and one to automatically center the view on the target. Experiments show these methods eliminate over 100 manual interactions required by the technician in navigated lumpectomy.

Beast brachytherapy is a technically-demanding soft tissue intervention that requires precise catheter placement. I propose an electromagnetic navigation system that consists of a tracked needle guide and a small sensor for catheter reconstruction. Phantom experiments show that needles can be placed more accurately when using the tracked needle guide compared to ultrasound guidance. Catheter reconstruction is shown to be accurate within 0.6 mm relative to computed tomography.

In conclusion, I have made synergistic contributions toward navigation in soft tissue surgery and brachytherapy. These contributions have been demonstrated in various experiments for two different procedures.

abstract: PhD


title: Access to Primary Health Care Services for Persons with Physical Disabilities in Rural Ghana

contributor:
Aldersey, Heather
Rehabilitation Science

subject:
Ghana
Primary Health Care
Access to Health Care
Rural Health
Persons with Physical Disabilities
Disability

abstract: Background: A growing body of evidence has shown that persons with physical disabilities experience substantial barriers in accessing primary health care (PHC) services in rural areas. Negative attitudes from health care providers and inaccessible health care facilities and equipment are common experiences that negatively affect access to quality health care for persons with physical disabilities. However, there is limited research that explores this issue in rural Ghana. Objective: I carried out this dissertation in three chapters to address this research gap. Chapter 3 synthesized published literature to understand the factors affecting access to PHC for persons with disabilities (PWDs) in rural areas globally. Chapter 4 explored the experiences of persons with physical disabilities in accessing PHC services in rural Ghana. Chapter 5 highlighted the perspectives of health care providers in delivering PHC services to persons with physical disabilities in rural Ghana. Method:  I employed framework synthesis and used framework analyses to analyze existing literature (chapter 3). I also used a qualitative descriptive design to conduct semi-structured interviews with 18 persons with physical disabilities (chapter 4) and 15 health care providers (chapter 5).  I used thematic analysis to guide the analysis of the interviews. Results: In chapter 3, I found that PWDs were unable to access PHC due to obstacles including the interplay of four major factors; availability, acceptability, geography and affordability. Chapter 4 revealed that participants shared their experiences under two overarching themes: limited facilities and lack of providers. Chapter 5 uncovered three major themes: challenges in providing health care; strategies in navigating the challenges; and positive experiences in providing health care. Implications: The information provided in this dissertation is potentially important to policy makers and PHC providers as it presents evidence on the barriers and facilitators to PHC access in rural settings. In particular, understanding this topic from multiple sources (existing literature, PWDs and providers) will be critical for policy design and client-centered service delivery in rural Ghana and potentially other low- and middle-income countries.

abstract: PhD


title: A Comprehensive Multi-Level Control System for Micro-Grids Operating in Islanded Mode

contributor:
Bakhshai, Alireza
Jain, Praveen
Pahlevani, Majid
Electrical and Computer Engineering

subject:
Micro_Grids
Power Electronics Converters
two-stage Converter
Droop Controller
Harmonic Compensation
Adaptive Controller

abstract:
This thesis presents a new control architecture tailored for single-phase Microgrids (MGs) operating in the islanded mode. The main feature of the proposed control architecture is its capability to improve the transient performance of the MG components, to have autonomous operation, to compensate for harmonics, and to offer a tight regulation of the voltage across the load. The presented control architecture includes a converter-level controller as well as a supervisory-level controller. The proposed converter-level controller is able to significantly improve the transient performance.
The converter-level control includes new power estimator, which can accurately estimate the active and reactive power values very fast. Thus, the transient performance is significantly improved. In addition, the converter-level controller includes
a new harmonic compensation system in order to deal with harmonics. The harmonic compensation system includes a hybrid load observer. The hybrid load observer is able to estimate both the harmonics component and the linear components of the load. Thus, the hybrid load observer allows the harmonic compensation system to detect, estimate, and compensate for various load harmonics and disturbances caused by nonlinear loads in MGs (e.g. synchronous and asynchronous harmonics, and DC components). The proposed harmonic compensation system can substantially increase the reliability of MGs in the islanded mode of operation where nonlinear/linear loads produce asynchronous/synchronous harmonics. The other main contribution of this thesis is a novel supervisory-level controller for power converters in MGs. The proposed supervisory-level control scheme further enhances the reliability and transient performance of MGs by providing predictive features to control systems. This predictive feature is produced by a new dynamic controller block, which sets the parameters for the grid-side controller and the ones for the source-side controller. The supervisory-level controller effectively harmonizes the source-side controller and the load-side controller in order to improve the transient performance and stability of MGs. The converter-level controller along with the supervisory-controller provide a very
reliable solution for MGs in order to deal with nonlinear loads and perform precise power flow control. Mathematical analysis, simulation and experimental results verify the feasibility of the proposed control techniques and demonstrate their superior performance.

abstract: PhD


title: ‘To recover a sense of the sacred in ourselves and in everything around us’: Exploring the place of spirituality in Canadian health promotion

contributor:
Power, Elaine
Kinesiology and Health Studies

subject:
spirituality
spiritual health
health promotion
ways of knowing

abstract: The field of health promotion advocates a socioecological approach to health which addresses a wide variety of physical, social, environmental, political and cultural factors. Encouraging a holistic approach, health promotion examines many aspects of health and well-being, including physical, mental, sexual, community, social and ecological health. Despite this holism, there is a noticeable absence of discussion surrounding spirituality and spiritual health in the discipline of health promotion. For this thesis project, I was interested in exploring how leading scholars in the field of health promotion, in Canada, understand the place of spirituality in health promotion. Using the fourth edition of Health Promotion in Canada (Rootman et al., 2017) as my sampling frame of recognized leaders in the field, I conducted thirteen semi-structured qualitative interviews with authors from the book. Situated within a critical health promotion approach which utilizes methodologies aiming for social justice, equity and ecological sustainability, I intend to open up possibilities for centering spiritual epistemologies and other ways of knowing that have been marginalized, such as Indigenous understandings of health and wellbeing. I argue that by avoiding spirituality within health promotion frameworks and education, the secularism of health promotion and its underlying values of Eurocentric knowledge production and science remain invisible and rarely critiqued. The absence of spirituality in health promotion signifies the ongoing colonialism of the field. This must be addressed if health promotion is to respond effectively to the calls to action from the Truth & Reconciliation Commission (2015), and if health promotion is to fulfill its promise of being inclusive, relevant and effective.

abstract: M.A.


title: Novel Methods of Factor VIII Tolerance Induction in Hemophilia A Mouse Models

contributor:
Lillicrap, David
Pathology and Molecular Medicine

subject: Hemophilia A, Factor VIII, inhibitors

abstract:
The most serious complication of factor VIII (FVIII) replacement therapy in hemophilia A (HA) patients remains the development of anti-FVIII antibodies (inhibitors). At this time, there are no methods to prevent inhibitor development and immune tolerance induction (ITI) therapy is difficult and expensive to administer. As such, novel approaches to establish FVIII tolerance are of great interest.
The presence of pro-inflammatory signals during early FVIII exposure has been identified as a risk factor for inhibitor development. Here we demonstrate that in HA mice, administration of a corticosteroid to pharmacologically suppress such signals during initial exposure to FVIII leads to antigen-specific tolerance durable for a minimum of 18 weeks. This was associated with a short-term increase in the proportion of thymic regulatory T cells and changes in thymic genes responsible for immune regulation.
Failure to establish central FVIII tolerance is also thought to contribute towards inhibitor development in HA patients. This process begins in the fetal period and therefore requires in utero exposure to the protein via transplacental transfer. Our data suggest that FVIIIFc, a novel fusion protein composed of FVIII and the Fc region of immunoglobulin G1, can undergo transplacental transfer in HA mice. However, the resultant in utero exposure offered minimal protection from inhibitor development later in life, and did so only in the context of HA mice that also lacked VWF.
FVIIIFc has also been associated with decreased immunogenicity and improved ITI performance when compared to conventional FVIII. We provide a potential molecular basis for this observation by showing the ability of FVIIIFc to engage the inhibitory FcγRIIB receptor of FVIII-exposed murine B cells. The protein was also able to induce suppressive downstream signaling such as increased SHIP phosphorylation, decreased ERK phosphorylation and decreased calcium flux in FVIII-exposed but not naïve murine B cells.
The work presented here provides preclinical evidence of three novel approaches to FVIII tolerance induction and increases our understanding of FVIII immunology.

abstract: PhD


title: Modification of Polysaccharides and their Use as Pickering Emulsifiers in Oil/Water Emulsions, Miniemulsion, and Microsuspension Polymerization

contributor:
Cunningham, Michael Dr.
Chemical Engineering

subject:
Pickering emulsion
Cellulose Nanocrystals
Miniemulsion Polymerization
Suspension Polymerization

abstract:
Emulsion and suspension systems are the basis for the formulation of a wide variety of products including pharmaceuticals, consumables such as food, personal care or cosmetics and commodity materials such as adhesives, paints or synthetic rubbers. These systems require surface active agents (surfactants) or emulsifiers to prevent phase separation. Conventional emulsifiers are derived from petroleum and can entail disadvantages such as ecotoxicity, skin irritation issues or formulation foaming problems, so the design of new emulsifiers that are biodegradable, non-toxic and, at the same time superior in performance, is worthwhile. Pickering emulsifiers (PE) obtained from polysaccharides are a promising new type of emulsion stabilizer and are the focus of this work.
First, the hydrophobization of polysaccharide-based materials was investigated. Cellulose nanocrystals (CNC) were grafted with CO2-responsive polymers prepared by and grafted via reversible-deactivation radical polymerization (RDRP). The effect of the graft molecular weight on the graft density was investigated in detail and was shown to have a direct influence on the dispersion behavior of the grafted CNC. The results suggested that a particular pKaH, minimum graft density and graft length are required to effectively switch the CNC from a hydrophilic to a hydrophobic state. Graft molecular weights of ~5-10 kg/mol and graft densities between 2-6 x 10-2 chains/nm2 yielded CO2-switchable CNC which shuttled reversibly into the organic phase under N2 and into the aqueous phase under CO2. The modified polysaccharides were then employed to stabilize oil- water emulsions and in subsequent polymerizations. The surface and interfacial properties of the PE, the shelf life stability and droplet sizes of the miniemulsions were studied in detail. The chain length of the grafted polymer, the graft densities, the degree of substitution and the concentration of PE were correlated to the properties of the final Pickering emulsions. The type of initiator and type of PE was shown to directly affect the miniemulsion and microsuspension polymerization kinetics, polymer particle size, and molecular weight distribution. It was found that very small amounts of PE are required to give stable emulsions, which, along with the sustainability aspect, could make these materials highly attractive for industrial applications.

abstract: PhD


title: An Examination of Personal Financial Literacy Teaching and Learning in Ontario High Schools

subject: youth financial literacy

subject: financial literacy curriculum and learning

subject: high school financial literacy teaching

abstract: The purpose of the study was to examine the experiences of current high school students, teachers, and high school graduates in Ontario regarding their experiences with personal financial curriculum and teaching at the secondary level, and to identify the ways in which this important educational experience may have helped prepare students to become financially literate. I sought to examine how helpful and productive financial literacy teaching and curriculum were at preparing students to confidently address personal financial issues they would inevitably face. I considered this overarching issue using a transdisciplinary lens from the perspective of the three stakeholder groups. Using a case study research design, the first of its kind in Ontario or Canada on this topic, I utilized interviews, artifacts, and surveys to uncover student and teacher experiential data across three high schools and two institutions of higher learning in southeastern Ontario. For the interviews and artifacts, there were 12 students and 12 teachers from three high schools. For the high school graduate surveys, there were 344 participants, drawn from one college and one university. Inductive thematic analysis was used for the interviews and artifacts; descriptive and inferential statistical analyses were used for the surveys, with some significance testing. The major findings were that current students and high school graduates perceived curriculum and teaching experiences as seriously lacking in effectively preparing them to be financially literate, and that a fundamental reorientation around transdisciplinary, student-led learning was key to transforming such learning into a more meaningful and valuable educational experience. The central finding from the teacher perspective was that such instruction should be mandated, properly supported and largely student-led; reaffirming the view that greater student learning, meaning and value were achievable with suitable enactment. Accordingly, the three stakeholder groups shared the view that curriculum and teaching in the area of personal financial literacy was largely absent and/or ineffective at meeting student interests and needs. With mandatory, properly supported, student-oriented (transdisciplinary) instruction, the potential exists for more effective and valuable learning, resulting in better equipped high school students that were properly prepared to successfully navigate financial issues and the path ahead.

abstract: PhD


title: Screening Assessments for Aquatic Invasive Species Using Species Distribution Models

contributor:
Arnott, Shelley
Johnson, Tim
Biology

subject:
Environmental niche model
Species distribution model
Fish
Invasive species
Risk assessment

abstract: Invasive species are a major cause of biodiversity loss in North American freshwaters. Once established, aquatic invasive species (AIS) can restructure food webs and change the abiotic or physical conditions of a water body. The ability of species distribution models (SDMs) to predict habitat suitability for AIS is of interest because they can be used to identify what species are likely to establish if introduced. Habitat suitability from SDMs could be used as a screening risk assessment to identify which species require more detailed risk assessments. However, SDM performance in areas that are spatially disjunct from their training has been understudied, specifically for aquatic species. I conducted two studies to assess the applicability of habitat suitability predictions created by SDMs to identify potentially invasive fish for further risk assessments. First, I compared the performance of three different SDM techniques (BIOCLIM, DOMAIN and, MaxEnt) for five different freshwater fishes (common carp Cyprinus carpio,burbot Lota lota, northern pike Esox lucius, lake trout Salvelinus namaycush, and brown trout Salmo trutta) when models were trained east of the Atlantic Ocean and evaluated in North America. DOMAIN models were best able to predict the potential distribution of fishes, but still broadly overpredicted the realized distribution of fishes. In areas with habitat conditions that were novel compared to training habitat conditions, predictions of habitat suitability were unreliable for all models.  Based on the information from my first study, I applied the DOMAIN SDM technique to 44 fishes considered an invasion risk to the Laurentian Great Lakes to determine if habitat suitability could be used to identify fishes that are unlikely to invade. No fishes could be removed from consideration as potential invaders based solely on habitat suitability because of large areas of novel habitat conditions. Using habitat suitability as a screening measure to select fishes for further assessment is a questionable process due to uncertainties when predicting in novel habitat conditions and broad overpredictions of fishes’ realized distributions. Instead, trends in habitat suitability should be used to help identify where pathways intersect high habitat suitability for many species.

abstract: M.Sc.


title: PDMS-Containing Polyurethane Forumulation for Anti-Smudge Coatings and Superhydrophobic Textiles

contributor:
Liu, Guojun
Chemistry

subject:
Polyurethanes
Superhydrophobic fabric
Anti-smudge
Water-based coatings

abstract:
Durable and transparent anti-smudge coatings that repel both water- and oil-borne contaminants have many potential applications.  Perfluorinated moieties were commonly used in the past to prepare water- and oil-repellant coatings, however these species are expensive and of significant environmental concern.   Further, organic solvents have been traditionally used to formulate such coatings, however such solvent-based coating formulations emit volatile organic compounds and are a safety hazard.
First reported in this thesis is the development of transparent and durable water-borne anti-smudge polyurethane coatings.  These coatings are obtained by casting micellar solutions of a blocked polyisocyanate dispersed in water using a graft copolymer, polyol-g-PDMS, where the polyol backbone is water soluble and PDMS denotes poly(dimethyl siloxane).  On these coatings, small 5-µL droplets of various liquids such as cooking and engine oils have no problem to glide cleanly off at substrate tilting angles < 5 °.  Artificial fingerprint liquids, inks, and paints readily shrink into tiny droplets after application on them and their residues after solvent evaporation are readily wiped off with a tissue.  Such waterborne coating formulations were also used to coat textile fibers, where they imparted superhydrophobic properties to the textiles.  For both systems, the challenges associated with switching from a solvent-based to a water-based formulation for the targeted coatings will be discussed.  The greenness of the coating formation process will also be highlighted for its practical value.
In the future work, poorer water sliding behavior of NP-GLIDE coating (coatings bear nano-pools of grafted lubricating ingredient for dewetting enablement) will be improved with in-situ formation of free photo-cleavage PDMS chains.  Also, the effect of chain length of PDMS to anti-smudge properties will be systematically investigated.  Further, the robustness of these coatings will be tested.

abstract: PhD


title: The Design and Personalization of Aim Assistance Algorithms

contributor:
Graham, Nicholas
Computing

subject:
Aiming
Aim Assistance
Game Design

abstract:
Aiming is the act of directing an action toward a target object, location, or direction. Many activities in games require aiming. In order for players to perform these activities successfully, they must be able to aim accurately. When an action is too challenging, the player can become frustrated. Players that are not able to aim accurately enough to perform an action well can be helped through in game systems called aim assistance algorithms. However, it can be challenging to identify how to appropriately assist players. Additionally, it can be difficult to determine how much assistance is required for individual players.
We have developed a novel taxonomy to classify aimed actions in games. The taxonomy classifies an aimed action based on its immediacy, target interaction, and embodiment. The classification can be used to inform the design of appropriate aim assistance algorithms.
We used this taxonomy to classify aimed actions in three games. Then, based on this classification we designed aim assistance algorithms for each game. We ran two experiments to evaluate these aim assistance algorithms by simulating players of varying skill levels. Our first experiment established a linear relationship between the level of assistance given to a player and their performance of an aimed action. This linear relationship allowed us to personalize our aim assistance algorithms for different skill levels.
The second experiment compared the effectiveness of personalized aim assistance algorithms to giving all players the same level of assistance. Personalizing the aim assistance algorithms resulted in players finishing rounds of games with closer scores.
This thesis highlights the importance understanding aiming so that players with different abilities can receive personalized support. Additionally, it also shows that personalizing assistance algorithms can result in more balanced game difficulty.

abstract: M.Sc.


title: Diagnostic and Prognostic Biomarkers for Early Prostate Cancer

contributor:
Berman, David
Pathology and Molecular Medicine

subject:
Prostate cancer diagnosis and prognosis
Biomarker discovery and validation
DNA methylation
Cancer epigenetics
Tumor suppressors
PTEN Immunohistochemistry

abstract:
Prostate cancer is diagnosed and treated primarily on the basis of histopathological assessment of biopsies and cancer extent. Unfortunately, this assessment, performed by pathologists on very small amounts of biopsy tissue, misrepresents patient’s true risk of having life-threatening cancer grade by as much as 50%. Hence there is an urgent need for robust diagnostic and prognostic biomarkers that can accurately identify patients with prostate cancer and stratify them according to the risk of developing aggressive disease state. We addressed this issue by focusing on DNA methylation, and PTEN and ERG protein markers in a large biomarker study.

During this study we overcame several technical challenges associated with a typical biomarker discovery/validation approach such as cohort development and sample collection, and recovery of high-quality nucleic acids from archival tissues for proper testing of selected molecular features in downstream analysis. There is emerging evidence supporting a role of DNA methylation in initiation and progression of prostate cancer. We assessed DNA methylation levels at 15 loci using methylation-specific PCR and measured differences in their abundance levels in benign and cancer tissue samples. Several DNA methylation alterations were found to be highly cancer-specific, and a subset of them were significantly associated with prostate cancer grade group and biochemical recurrence.

Loss of the PTEN tumor suppressor is a powerful prognostic biomarker in prostate cancer. However, the significance of tumour heterogeneity and partial PTEN loss are not clearly defined, nor are interactions between PTEN loss and the TMPRSS2-ERG fusions, the most common genetic aberration found in prostate cancer.  We investigated their prognostic utility using immunohistochemistry. PTEN loss, but not ERG fusion, was significantly associated with biochemical recurrence. In addition, quantitative assessment of PTEN protein loss showed more prognostic relevance than conventional binary assessment. By conducting thorough assessment of DNA methylation alterations, and genetic mutations involving PTEN and ERG, we provide necessary evidence needed to demonstrate the prognostic utility of these markers.

abstract: PhD


title: Exploring Different Approaches to Improve the Analytical Performance of Inductively Coupled Plasma Optical Emission Spectrometry with Pneumatic Nebulization or Electrothermal Vaporization

contributor:
Beauchemin, Diane
Chemistry

subject: inductively coupled plasma optical emission spectrometry,

subject: pre-evaporation

subject: electrothermal vaporization

abstract:
This thesis is aimed at exploring new diverse approaches for improving the analytical performance of inductively coupled plasma (ICP) optical emission spectrometry (OES) with pneumatic nebulization (PN) or electrothermal vaporization (ETV).
      First, a new infrared (IR)-heated PN system was developed to enhance sample transport efficiency and concurrently improve sensitivity, detection limit and plasma robustness of ICPOES. A cyclonic spray chamber was modified so as to insert an IR lamp heater inside it. The modified cyclonic (MC) spray chamber was heated up to 150 °C. Using a pre-evaporation tube (PET) between the MC spray chamber and the plasma torch was also investigated. Under optimum operating conditions, a 2-5 fold improvement in sensitivity and 2-7 fold improvement in detection limit were achieved for 26 elements compared to conventional PN at room temperature.
      Second, the analytical performance of ICPOES was improved by IR heating of commercially available spray chambers using different types of IR heaters, namely ceramic block and ceramic beaded IR heaters. For 29 elements, the detection limit improved by, on average, 2-3 fold with the rope heater and 5-10 fold with the block heater. All IR-heated systems enabled the accurate analysis of a certified reference material (CRM) of waste water.
      Third, the effect of IR heating of the top surface of a cyclonic spray chamber on the analytical performance of ICPOES was investigated. Upon IR heating (up to 150 °C), sensitivity and detection limit improved  by 3-5 fold and 4-12 fold, respectively compared to those with the same system at room temperature. The IR-heated system allowed the accurate multi-elemental analysis of two CRMs.
      Finally, addition of H2, N2 or water vapour to the central gas flow of the plasma was assessed to enhance the analytical performance of solid sampling (SS) ETV-ICPOES. Sensitivity and detection limit were significantly improved upon sheathing the sample aerosol with H2, N2 or water vapour for 11 elements compared to those with conventional SS-ETV-ICPOES. To the best of the author’s knowledge, this is the first published study of the effect of adding N2 to the central gas flow of the plasma on the analytical performance of SS-ETV-ICPOES.

abstract: PhD


title: Radical Copolymerization of Hydroxy-Functional Monomers

contributor:
Hutchinson, Robin A
Chemical Engineering

subject:
Coatings
Pulsed Laser Polymerization
Modeling
Reactivity Ratio
Propagation Kinetics
HEMA
HEA
BMA
Semi-Batch
ESI-MS
Solvent Effects
Copolymerization

abstract:
Solvent-borne acrylic resins are commonly used in automotive coatings formulations due to the superior characteristics they provide to the final products. Hydroxyl-functionality, incorporated by selection of 2-hydroxyethyl methacrylate (HEMA) or 2-hydroxyethyl acrylate (HEA) as monomers, is required to ensure that the low molecular weight chains produced by free radical copolymerization participate in the cross-linking reactions to form the final coating product. Hence, the knowledge of their copolymerization kinetic coefficients is vital for both process and recipe improvements.
In the first part of this work, the pulsed laser polymerization (PLP) technique is paired with size exclusion chromatography (SEC) and nuclear magnetic resonance (NMR) to provide kinetic coefficients for the copolymerization of HEMA with butyl methacrylate (BMA) in various solvents. These experiments provide insights into the influence of solvent type on the copolymerization reactivity ratios and composition-averaged propagation rate coefficients.
In the second part of the study, small scale semi-batch reactions were conducted to investigate the influence of temperature, monomer composition and initiator content on the copolymerization of HEA with BMA. The effect of HEA content and copolymer molecular weight (MW) on resin performance was investigated by determining the amount and MWs of non-functional polymer that could be extracted after forming crosslinked films from the resins. Characterization of the extractable material by NMR, SEC, and by electrospray ionization mass spectrometry (ESI-MS) confirmed that the polymer extracted contained negligible levels of HEA. The experimental results were compared to Predici® and Monte Carlo simulations of the system

abstract: M.A.Sc.


title: Frictional Markets, Asset Liquidity and Business Cycles

contributor:
Sun, Amy Hongfei
Lloyd-Ellis, Huw
Economics

subject:
Search Frictions
Asset liquidity
Business Cycles

abstract:
This thesis consists of three essays that use dynamic stochastic general equilibrium (DSGE) models to study the interactions between the goods sector and the financial sector of the economy in the presence of search frictions in the asset market.
In Chapter 2, I construct a real business cycle model with search frictions in the asset market to endogenize asset liquidity. In the model, asset liquidity depends on the probability of matching a seller with an appropriate buyer. In this way, an exogenous shock in the real sector can cause asset liquidity to fluctuate by changing the tightness of the asset market. In this chapter, I demonstrate the existence of steady states, and examine the properties of the equilibria.
In Chapter 3, I used the model discussed in Chapter 2, together with productivity and liquidity  hocks estimated using a structural vector autoregression (SVAR) on U.S. data to investigate how asset liquidity and asset prices fluctuate in response to productivity and liquidity shocks, and how, in turn, these fluctuations magnify the impact of productivity shocks on economic activity. In addition, I compare the business cycle properties generated by the baseline model to models without search frictions in the asset market in order to assess the importance of search frictions. I find that productivity and liquidity shocks are equally important in explaining business cycles. The model also shows that productivity shocks generate pro-cyclical movements of hours worked and asset prices, which is not the case for liquidity shock.
In Chapter 4, I compare two models with search frictions in the asset market that differ in terms of their assumptions regarding the supply and the demand sides of the market. Two factors discussed in the paper are adjustment costs and government bonds.  After calibrating the models, I find that the model with both adjustment costs and government bonds generates pro cyclical movements in asset prices. In addition, the inclusions of adjustment costs significantly enlarge the volatility of asset prices because the adjustment costs prevent the asset price from immediately regressing to the steady state.

abstract: PhD


title: Confidence intervals and measures of significant change for KINARM Standard Tests

contributor:
Scott, Stephen
Neuroscience Studies

subject: KINARM

abstract:
Neurological assessment plays a pivotal role in the overall diagnostic and prognostic process of patient care. The effectiveness of the various examinations and methods of neurological assessment are based on the accuracy and precision of the measure. In other words, a good assessment tool should properly reflect the participant’s abilities in any tested domain, while also providing the same score of those abilities over repeat assessments. Traditional neurological assessment tools are faced with many challenges when attempting to meet this criteria. This is primarily the result of many tools relying on the subjective decisions and rely on coarse rating scales in order for clinician’s in order that clinicians can maintain similar scores. A potential alternative is robotic technologies for neurological assessment. Overall, these robotic tools can provide a more objective and reproducible measure of participant performance, when compared to traditional tools.

The purpose of this thesis was to assess participants on the KINARM standard tests with the goal of quantifying performance variability across repeat evaluations. Utilizing the KINARM exoskeleton robot, control participants were assessed twice with the maximum time between evaluations set at 1 week. The tasks are divided into 4 categories, motor tasks, motor-cognitive tasks, cognitive tasks, and one sensory task.

The results of this thesis revealed confidence intervals smaller than the population interval in 99% of task parameters. Significant learning effects were more prevalent in cognitive and motor-cognitive tasks when compared to sensory and motor tasks. Confidence intervals for TaskScores, the global performance measure, ranged from 0.74 to 1.68 for all KINARM standard tests. Moreover, significant change cut-off values ranged from 1.03 to 2.36 with 55% of tasks shown to have significant learning effects over repeat assessment.

These metrics will improve the interpretation of participant performance with respect to individual parameter scores. They also provide a solid framework for many future KINARM studies, most notably the emerging problem of reducing overall assessment time.

abstract: M.Sc.


title: Assessing long-term environmental trends in Ontario lakes that support Lake Trout (Salvelinus namaycush)

contributor:
Smol, John
Biology

subject:
paleolimnology
diatoms
lake trout
dissolved oxygen
limnology

abstract: Oxygenated habitats for Lake Trout (Salvelinus namaycush) are projected to deteriorate with climate warming. However, a paucity of long-term limnological monitoring data impedes the ability to determine if concentrations of end-of-summer volume weighted hypolimnetic oxygen (VWHO), a management-relevant metric of deepwater oxygen conditions, have changed and if so, what environmental variables are driving these changes. This research uses limnological and paleolimnological records to investigate long-term trends in VWHO and variables that influence VWHO in Ontario Lake Trout lakes across multiple spatial and temporal scales. An investigation of ~40 years of biweekly temperature-oxygen profiles collected from six lakes in south-central Ontario tracked recent (post-2010) increases in end-of-summer VWHO and in the amount of optimal Lake Trout habitat. These changes were driven by increases in both hypolimnetic volume and hypolimnetic oxygen concentrations. Using paleolimnology, the temporal scope of this thesis was extended to analyze environmental conditions in three Lake Trout lakes over the past 100–150 years. These data suggested primary production has increased independent of lake nutrient concentrations – a significant finding as current management strategies primarily rely on limiting phosphorus loading to prevent hypolimnetic oxygen depletion. To expand the spatial scope, sediment cores from four additional study lakes (seven lakes in total) were investigated. This included an analysis of sedimentary records from two basins within the same lake, which demonstrated the individual sensitivities of unique basins to localized stressors. Paleolimnological inferences from all seven study lakes indicated that most lakes have increased with respect to thermal stability, lakewater total organic carbon (TOC) concentrations, and whole-lake primary production over the past century. Meanwhile, only two of the study lakes appear to have undergone nutrient enrichment. These findings are significant as they emphasize the need to incorporate the combined influence of warming and rising TOC concentrations (in addition to limiting nutrient loading) into management strategies for coldwater fish habitat. Collectively, this research provides insight on temporal and spatial trends of environmental variables that can impact oxygenated habitat for Lake Trout. The observed VWHO increases (in both limnological and paleolimnological data) emphasize the complex influence of multiple environmental drivers on coldwater fish habitat.

abstract: PhD


title: Robert Lowth's Hebraic Sublime and the "Ample Field of Poetry"

contributor:
Pierce, John
English Language and Literature

subject:
romanticism
sublime
eighteenth century
aesthetics
poetry
bible
robert lowth
christopher smart
william blake
criticism
prophecy

abstract: This dissertation is a study of Robert Lowth’s theorizing of the Hebraic sublime and its posterity in the second half of the eighteenth century. I begin with an exploration of Lowth’s description of the sublime across Lectures XIV-XVII, showing how, counter to his own claims about copying Longinus, the principle that underlies his sublime rhetoric— figurative dissimilarity—is the opposite of the principle that Longinus repeats several times in the Peri Hypsous. Whereas Longinus argues that figures and tropes should be used inconspicuously, Lowth argues from the Hebrew Scriptures that the conspicuity of the rhetorical construction is key to the excitation of the passions that follows the sublime encounter. Seeking to contextualize Lowth’s theorizing within intersecting critical, social and literary discourses, I investigate Lowth’s differing opinions of the concept of enthusiasm. Though he preached against it as a bishop in 1767, his earlier, positive images of enthusiasm in the Lectures reflect the influence of John Dennis’s Grounds of Criticism. Having contextualized Lowth’s theorizing, I turn to explore his influence on Christopher Smart and William Blake. Both poets, bearing a strong individual poetic vision, find in Lowth’s Lectures a sublime rhetorical toolkit as well as a model of prophetic authority. Their relation to Lowth can be traced on a trajectory: while Smart shares Lowth’s commitment to the church as an institution without his conservative theology, Blake uses biblical language and imagery but rejects both orthodoxy and the church as an organization. This trajectory ends with Percy Bysshe Shelley, who affirms the prophetic authority enabled by Lowth’s Hebraic sublime, but without the rhetoric he described nor the Christianity that motivated his study.

abstract: PhD


title: Suppression of the Efficiency Roll-Off Characteristics in Solution-Processed Lanthanide-based Organic Light-Emitting Diodes

contributor: Physics, Engineering Physics and Astronomy

subject:
Organic Light-Emitting Diodes
Lanthanide Complex
Efficiency Roll-Off
Near Infrared Electroluminescence

abstract:
Organic light-emitting diodes (OLEDs) have gained a tremendous amount of interest, due to their applications in display and solid-state lighting technologies. This interest mainly arises from the easy and inexpensive manufacturing processes for the fabrication of lightweight, transparent, flexible, and large-area devices. While OLEDs have now reached the stage of commercialization, there are still some serious issues associated with exciton-exciton and exciton-polaron annihilation mechanisms, which reduce their efficiency particularly under the high current densities required to achieve a high level of brightness. This phenomenon is known as efficiency roll-off. On the other hand, since most luminescent organic semiconductors are in principle four-level lasing systems, color-tunable and easy-to-manufacture optically pumped organic solid-sate lasers (OSLs) have attracted a lot of attention, due to their applications in biological sensing, spectroscopy, and data communication. However, highly demanded portable electrically driven continuous-wave (CW) OSLs (organic diode lasers) have not been realized to date. This is mainly because of the above-mentioned efficiency roll-off issue under the high current densities required to achieve lasing threshold in OLEDs.
Visible-emitting trivalent lanthanide ions (Ln3+) are promising emitters for OLED applications. They are also known for their excellent lasing properties, owing to their long excited-state lifetimes, favoring population inversion in optically pumped plastic lasers and amplifiers. Furthermore, near infrared (NIR)-emitting trivalent lanthanide ions are important emitters in telecommunication applications in the 900-1600 nm spectral range. Despite the fact that lanthanide-based emitters have been studied in the NIR-emitting OLEDs, their efficiency is still much lower than in their visible-emitting counterparts. Moreover, like other types of OLED, lanthanide-based devices suffer from the aforementioned efficiency roll-off mechanisms. In the present thesis, we show enhanced efficiency from solution-processed NIR-emitting lanthanide-based OLEDs. We also demonstrate unprecedented low efficiency roll-off characteristics in both visible and NIR-emitting lanthanide-based devices.

abstract: PhD


title: Inequalities in Educational Choice and Outcomes

contributor:
Ferrall, Christopher
Economics

subject:
Indigenous education
credit constraints
educational attainment

abstract:
This thesis examines several topics relating to family background and educational achievement. Chapter 2 examines the influence of credit constraints and government policy on college choice and educational attainment in the United States. We propose a discrete dynamic programming model of human capital accumulation where agents make schooling, borrowing, saving, and work decisions. Structural parameters of the model are estimated using from the 1997 cohort of the National Longitudinal Survey of Youth (NLSY97) and Generalized Method of Moments (GMM). The fitted model underpredicts on a number of key dimensions, but provides a preliminary framework to explore counterfactual policies. These policy experiments indicate that college choice and completion are not influenced by changes to tuition levels, interest rates or grants. We find that the non-pecuniary benefits of attending private schools plays an important role in individual college choice.

Chapters 3 and 4 analyze the test gap between ethnic minorities and white students in Canada with a focus on the Indigenous-white test score gap. In Chapter 3, we use data from the National Longitudinal Survey of Children and Youth to show that after controlling for a rich set of observables, students who self-identify as Indigenous perform 0.31 standard deviations lower on a standardized math test compared to their white counterparts. Counterfactual distributions from the decomposition method of Lemiuex (2002) suggest that the test gap between low performing students is more than eliminated after accounting for the differences in the returns to and levels of observable characteristics; however, a sizeable gap remains among high performing students. Chapter 4 further explores the timing of the emergence of the test gap between Indigenous and non-Indigenous youth. We find that the test score gap emerges at 12 years of age, and, despite renewed attention to Indigenous education, the test score gap has not improved between 1994 and 2009.

abstract: PhD


title: Optical Visualization of Two Phase Flow in PEM Electrolyzers

contributor:
Pharoah, Jon
Mechanical and Materials Engineering

subject:
PEM electrolyzer
Two-phase flow
Bubble formation
Optical visualization

abstract:
Polymer electrolyte membrane (PEM) electrolyzers are ideally suited to pairing with renewable energy sources given the capability to operate at high current densities and transition between different potential loading.  To become commercially competitive however PEM electrolyzers require improvements in performance and cost reduction.  Much of the technology for PEM electrolysis has comes from PEM fuel cells, leaving room for improvement.  The slower reaction kinetics and highly corrosive environment at the anode due to the oxygen evolution reaction (OER) in particular requires research and development to increase efficiency.  This study focuses on the behavior of two-phase flow of oxygen in water as it relates to cell performance.  Optical visualization with a high speed camera was used to observe oxygen bubbles at the anode during PEM electrolysis.

Images of oxygen bubbles in two-phase flow were successfully recorded using three experimental setups: a sample holder submerged in a water filled tank, a modified channel-less PEM electrolyzer cell and a modified PEM electrolyzer cell with optically accessible channels.  Image processing pathways were successfully developed using MATLAB and Fiji to study individual bubbles in all setups.  The channel-less electrolyzer setup operated at a much lower performance than standard PEM electrolyzer cells.  It is suspected that contact resistance reduces the electrochemical performance either as a result of the in-plane conductivity for the PTL being very high or large ohmic contact losses where the PTL contacts the current distributor.  The optically accessible channel design was able to operate at performances comparable to an unmodified cell and bubble images were captured in-situ to observe bubbly to annular flow regimes over a range of current densities.  This investigation showed that flow field channel aspect ratio is an important determinant to cell performance.

abstract: M.A.Sc.


title: Electrochemical Water Oxidation by Heterogenized Iridium-NHC Precatalyst

contributor:
Crudden, Cathleen
Chemistry

subject: Heterogenized Water Oxidation

abstract: Hydrogen production from water splitting provides a potential source for clean energy storage. However, this process requires catalysts that can oxidize water to provide a source of electrons for proton reduction. Various molecular catalysts have been investigated based on their high activity and tunability, but their solubility and limited stability restrict their use in practical applications. Here, we reported a heterogenized iridium-NHC catalyst that can drive water oxidation reaction by electricity directly. The catalyst was prepared by two steps: first the NHC was immobilized on a gold surface, followed by reacting with [IrCp*Cl2]2. This strategy provides a convenient way to systematically evaluate catalysts under optimized conditions, potentially leading to new insights into electrochemical water oxidation processes and water oxidation catalyst design.

abstract: M.Sc.


title: Advances in 5-(Hydroxymethyl)Furfural Production From Cellulose Via CO2-Catalysis

contributor:
Jessop, Philip
Champagne, Pascale
Chemistry

subject:
chemistry
biofuel
carbon dioxide
HMF
hydroxymethyl furfural

abstract: The global economy must make a radical shift to lower carbon emissions to avert large-scale impacts from climate change. Fuels derived from widely available biomass such as macroalgae, have the potential to limit the CO2 impact of transportation by reducing the reliance on fossil fuels. 5-(Hydroxymethyl)furfural (HMF) is a jet fuel precursor that can be produced from carbohydrates such as those available in macroalgal biomass. However, researchers pursuing the production of HMF from inexpensive carbohydrates have struggled to achieve high yields under economically sustainable conditions due to low yields and the formation of side-products such as organic acids and humic oligomers. Current methods for HMF preparation typically utilize reagents, reaction conditions and purification protocols that are not suitable for commercial biofuel production. In 2010, high-pressure CO2 was identified as a potential catalyst for HMF production. This thesis describes work done to improve the understanding of CO2-catalyzed HMF production. An initial study examined the effect of temperature, pressure and salt selection on CO2-catalyzed HMF production from glucose. It was found that an initial concentration of 1% glucose (in pentanol containing 10 mL of 10% CaCl2 solution) reacted at 200 oC under a pressure of 7 MPa of CO2 could produce HMF in a 64% yield. These same conditions were then applied to starch, xylan, and cellulose, and yields of 55%, 51%, and 22%, respectively, were obtained. Efforts were then made to improve HMF yield from cellulose by improving the reaction conditions and it was found that application of a temperature of 200 oC over 4 hours of reaction time gave the best yields (43% total furans), although the relationship between CO2 pressure and HMF production appears to be weaker than initially anticipated. Exploratory work was also done assessing the use of novel 5-HMF production methods, such as recycle-experiments and simultaneous production of the acetone adduct. Overall, this thesis work offers evidence that CO2-catalyzed production of 5-HMF and furfural from cellulose is possible, and assists in determining the best conditions for preforming this conversion.

abstract: M.Sc.


title: Mechanisms of Social Cognition in Early Episode Psychosis

contributor:
Bowie, Christopher R.
Psychology

subject:
psychosis
social cognition
jumping to conclusions
motivation

abstract: The mental abilities required to identify, understand, and respond to social information are broadly referred to as social cognition, and individuals with schizophrenia spectrum disorders display significant impairments in these abilities. Social cognition has been identified as a primary contributor to functional outcomes in psychosis, and represents a critical target for treatment and recovery. Although previous research has extensively examined the magnitude of social cognitive impairments across phases of psychosis using a variety of measures, the factors that contribute to social cognition are still relatively unknown, but may hold the key to improve our understanding of why these impairments arise and persist over time. Because traditional measures of social cognition place demands on neurocognitive and motivational resources, it was hypothesized these illness-related factors would be implicated in the social cognitive performance of individuals in the early stages of a psychotic disorder. In two studies, tasks of social cognition were experimentally manipulated to assess for the influence of cognitive biases and amotivation on performance in a sample of early psychosis patients (n = 35) and demographically-matched community controls (n = 35). Results from these studies demonstrated that jumping to conclusions, a cognitive bias common to psychosis, and extrinsic motivators during testing were directly associated with outcomes on tasks of social cognition, and that these factors were particularly relevant to the performance of the early psychosis group. These studies add to the existing literature on social cognition in psychosis by emphasizing the role of jumping to conclusions and amotivation, which may be informative for refining the theoretical model of social cognition and enhancing interventions designed to remediate these impairments. Moreover, the functional relevance of social cognition highlights the importance of ongoing research efforts using experimental designs to better understand the illness-related factors most strongly associated with social cognition in psychosis.

abstract: PhD


title: Revisiting the Nature of Transformational Leadership: How Followers' Affect Matters

contributor:
Barling, Julian
Business

subject: leadership followership emotion

abstract: The seven studies within this dissertation investigate the nature of transformational leadership. I consider whether transformational leadership is affective, whether it is multidimensional, and whether people perceive differences in the magnitude of transformational leadership. The first study tests the idea that the dimensions of transformational leadership have unique emotional valences. Studies 2, 3, 4, and 5 propose that followers’ ability to recognize emotion will affect their perceptions of transformational leadership; and examines whether individuals higher in emotion recognition are better able to identify and differentiate between the dimensions of transformational leadership. In Study 6, I manipulate the magnitude of transformational leadership to assess whether followers are able to perceive differences between small, medium, and large displays of transformational leadership. This study also tests whether follower emotion recognition and positive mood influence the identification of magnitude. Finally, Study 7 uses confirmatory factor analysis to test the validity of the multidimensionality of transformational leadership by examining its factor structure with followers’ emotion recognition and liking of their leader included in the model.

abstract: PhD


title: Second Place at the Polish Pow Wow

contributor:
Beeman, Chris
Education

subject: Métis cultural rediscovery

abstract:
Abstract
This paper begins with an Indigenous buffalo teaching. It is followed by aspects of my own story of Métis cultural rediscovery. My hope is this will provide insight into why I am undertaking this writing, as well as provide a means to share information. The hypothesis of this thesis indicates that there exists a gap in knowledge and approach in education which can lead to reduced participation and success from Métis learners. A core premise indicates reclaiming a healthy and prideful identity is beneficial for learning success for Métis, both in formal educational settings, as well as informal and lifelong learning endeavors. This thesis was designed to provide some understanding of the meaningfulness of reclaiming a Métis identity.
The questions informing this study are: How does story provide insight on Métis learning? Considering Métis history, what are ways to strengthen Métis positive identity in formal education settings?
What emerges from the author’s story that may broaden understanding of Métis learning and transformative mindset?
Several themes were identified and discussed related to these questions. This thesis is organized around several chapters, each containing stories that weave in and out of the points I want to make about Métis identity, features lost and reclaimed, and education for Métis people.

abstract: M.Ed.


title: Assessing the Geographic and Socioeconomic Determinants of Private Well Water Testing Practices in Southern Ontario

contributor:
Richardson, Harriet
Hynds, Paul
Majury, Anna
Public Health Sciences

subject:
Public Health
SES
Well Water
Southern Ontario
Well Testing Practices
Socioenvironmental research
Repeat Well Testing

abstract:
Purpose: An estimated 4.3 million Canadians use private wells for daily water consumption, however well testing rates are declining, potentially resulting in an increased risk of exposure to groundwater contaminants associated with acute gastrointestinal infections (AGIs). Regular testing of well water is recommended to reduce the risk of consuming contaminated groundwater.
Methods: This study used a large dataset composed of well testing and well construction data maintained by the government of Ontario. All tests conducted in southern Ontario between 2012 and 2016 were included. Log-binomial regression was used to investigate the association between SES and well water testing practices, with season and index test status included as covariates. Rurality, based on population density, was assessed as an effect modifier of this relationship.
Results: The dataset contained information for 417,406 individual wells, 114,820 (27.51%) of which were tested during the study period, with two thirds (66.72%) of these sampled more than once. In urban (>400 people/km2) and peri-urban regions (>150 and <400 people/km2), wells located in low socioeconomic status (SES) areas were 14% and 15% less likely to be tested compared to high SES areas (RR: 0.86 (0.78, 0.95) and RR: 0.85 (0.76, 0.94), respectively). In rural regions (<150 people/km2), wells located in low SES areas were 13% more likely to be tested compared to high SES areas (RR: 1.13 (1.11, 1.15)). SES was not significantly associated with repeat testing in urban/peri-urban regions and was weakly associated in rural regions (RR = 1.06 (1.04, 1.07)).  Positive index tests were associated with a 17% increased likelihood of repeat testing when compared to negative index tests, while accounting for the effect of season and SES (RR = 1.17 (1.16, 1.18))
Conclusion: Rurality and SES are important predictors of the decision to test a well, with index test status the most influential predictor of repeated well testing. Further research is required to assess the influence of SES at an individual level. These findings provide important information for public health agencies in the context of strategic and targeted water testing promotion.

abstract: M.Sc.


title: Investigating Selenium Usage Challenges and Reducing the Performance Overhead of Selenium-based Load Tests

contributor:
Hassan, Ahmed
Computing

subject:
Load testing
Empirical study
Selenium
Stack Overflow

abstract: Selenium automates the testing of web applications. Quality Assurance (QA) engineers usually write Selenium scripts to test the content that is rendered in a browser and simulate user interactions with the web content for web applications. Apart from test automation, Selenium is also used to perform load testing and web scraping tasks. Selenium has gained a great amount of attention from users as observed from the trend of Selenium-tagged questions on StackOverflow. In this thesis, we first explore the Selenium-related questions on StackOverflow to understand users' questions about Selenium, programming-language specific issues, browser-specific concerns and the difficult aspects of Selenium. Some of the notable findings from our empirical study are:  Questions about Python have become the most frequent and the fastest growing programming language related questions in Selenium, while questions on Java have become stable in recent years. We also find that Chrome tag is the most frequently used browser tag among other browser related tags associated with Selenium. Several users discuss performance issues in Selenium tests on StackOverflow. Prior work on Selenium also points out that Selenium tests are resource intensive. As Selenium needs to launch a browser for each instance (e.g., a client) of a test, it is usually very resource consuming to run a load test using Selenium as one would need to run thousands of user instances. We propose an approach to reduce the performance overhead of Selenium-based load tests. Our approach shares browser instances between user instances, thereby reducing the performance overhead that is introduced by launching many browser instances. The main contribution of this thesis is that our approach can significantly increase the number of user instances that can be tested on a test driver machine without overloading the machine. We improve the testing efficiency of Selenium-based load tests by at least 20%. The insights that we share in this work can help the developers of Selenium understand how Selenium is used in practice and how they can offer better support for Selenium. Further, software practitioners can benefit from our approach to reduce the performance overhead of Selenium-based load tests.

abstract: M.Sc.


title: Differential Contributions of RET-isoforms to Tumour Invasion

contributor:
Mulligan, Lois
Pathology and Molecular Medicine

subject:
RET
Receptor tyrosine kinase
Cancer
Thyroid
Pancreas
Invasion
Migration
GDNF
Isoform

abstract: RET is a receptor tyrosine kinase (RTK) which is normally activated at the cell surface by glial cell line-derived neurotrophic factors and plays critical roles during embryogenesis. RET is expressed as two protein isoforms, RET9 and RET51, named for the lengths of their isoform-specific tail sequences. RET also acts as an oncogenic driver in several cancers, and its expression has recently been linked to aggressiveness in multiple tumour types. However, the specific contributions of RET to tumourigenesis are not yet well described. Here we demonstrate that expression of constitutively activated RET in thyroid carcinoma cells contributes to growth, survival, motility and invasiveness, and that loss of RET expression coincides with reduced mesenchymal gene expression with gain of epithelial markers. We showed that activation of wildtype RET in pancreatic adenocarcinomas enhanced directional motility and invasion, suggesting that expression of RET may contribute to invasion towards sources of ligand, such as peripheral nerves. We further showed that RET activation induced invadopodia formation, and that RET interacted with TKS5, an adaptor protein critical for invadopodia formation and function. We observed functional differences between RET isoforms, and demonstrated in both thyroid carcinoma and pancreatic adenocarcinoma cells, that RET51 is more potent than RET9 in enhancing expression of mesenchymal genes, promoting invadopodia formation, cell polarization, cell motility and invasion. Together, our work suggests RET expression, particularly that of RET51, may be useful as a marker for tumour invasiveness in a number of clinically challenging cancers, and that RET may be a potential therapeutic target for treatment of these diseases.

abstract: PhD


title: Investigation of Hydroisomerization Catalysts and Reaction Conditions to produce Branched-Chain Fatty Acids

contributor:
Peppley, Brant
Chemical Engineering

subject:
Biolubricants
Fatty Acids
iso-stearic acid
Zeolite
Catalysis

abstract: Fatty acids (FAs) from vegetable oils can be used as feed to produce renewable hydrocarbons and bio-lubricants. Naturally occurring FAs are, however, susceptible to oxidative attack and have operating temperature limitations due to poor cold flow properties. Converting FAs into saturated branch-chain isomers would alleviate these restrictions. Combining the hydrogenation and skeletal isomerization of C=C double bonds in FAs required to form saturated branch-chain FAs into one single hydroisomerization reactor would significantly reduce the complexity and costs of production of these renewable hydrocarbons. This project thus investigated possibility of hydroisomerization of oleic acid to produce saturated branched-chain FA isomers in a single reactor by developing and testing hydroisomerization catalysts. In this process, acidic solid surfaces promote isomerization reactions, while hydrogenation is catalyzed by active metals. Bifunctional Pt on H+-Beta zeolite catalysts were synthesized through incipient wetness impregnation and tested in a batch reactor. Hydroisomerization was unsuccessful as hydrogenation of double bonds was favoured over the competing skeletal isomerization reaction, resulting in a saturated straight-chain FA. The melting point of products increased from 13 °C to 62 °C. Due to these findings, preliminary exploration of effects on skeletal isomerization of oleic acid to form bc-isomers was instead investigated by omitting platinum. Reactions were conducted in the presence of N2 or H2 gas at varying pressures. Triphenylphosphine was added to some experiments to block the external acid sites of the zeolite, and deionized water was added as a co-catalyst. Four zeolites of interest, 12.5 silica-alumina ratio H+-Beta, 19 silica-alumina ratio H+-beta, SAPO-11 and MCM-41, were also tested. These zeolites represented varying pore sizes and acidity (Silica to Alumina ratio). It was shown that the pore size has a greater effect on catalytic activity than acidity. A maximum bc-isomer yield of 63 wt% was achieved with 5 wt% H+-Beta zeolite in oleic acid under a H2 pressure of 15 bar and reactor set-point of 280 ºC, stirred for 6 h in a batch reactor. Product analysis indicated that trans-isomers and lactones were also produced as by-products of the skeletal isomerization.

abstract: M.A.Sc.


title: An evaluation of hyaluronic acid and poly-L-lysine polyelectrolyte layers on alginate microspheres for use in protein-triggered drug release

contributor:
Wells, Laura
Chemical Engineering

subject:
polymer microspheres
drug delivery

abstract:
Age-related macular degeneration (AMD) is the leading cause of vision loss in developed countries in those 50 years of age and older. Increased expression of the protein vascular endothelial growth factor (VEGF) plays a large role in the onset and progression of the advanced, wet form of AMD. To deliver drugs to the posterior chamber of the eye to treat diseases such as AMD, intravitreal injections are performed. Due to the side effects associated with intravitreal injections, such as retinal detachment and hemorrhage, it is advantageous to reduce the frequency of injections required for treatment. This thesis investigates sustaining the release of drug through encapsulation in polymer microspheres coated with polyelectrolyte layers of poly-L-lysine (PLL) and hyaluronic acid (HA) with the potential for protein-triggered release using aptamers.
	In this research, the feasibility of crosslinking HA with aptamer-containing DNA oligomers for protein-triggered release (for example, in response to VEGF in AMD) was evaluated and the crosslinking of HA layers by methods of click chemistry and through a carbodiimide reaction were compared. The lysozyme aptamer (used for proof-of-concept) in the DNA crosslinker retained its affinity for lysozyme, although lower binding occurred when incubated in phosphate buffered saline (PBS). The lysozyme aptamer showed moderate specificity when incubated with bovine serum albumin (BSA) or chymotrypsin as the aptamer did not bind BSA, however there was slight binding when incubated with chymotrypsin.
	The properties of the PLL/HA layers on calcium alginate microspheres affected the in vitro release of encapsulated model drug FITC-dextran (MW 10 kDa) into PBS. Coating microspheres with 3 polyelectrolyte layers consisting of PLL, HA crosslinked with poly(ethylene glycol) diamine at a 1:5 molar ratio of amine groups to HA carboxyl groups, and a final layer of PLL did not change the release profile of FITC-dextran in comparison to release from microspheres coated with un-crosslinked layers. Increasing the number of layers on the microspheres from 3 to 5 layers significantly decreased the amount of encapsulated FITC-dextran released. However, increasing the number of layers to 7 layers did not further sustain the release of FITC-dextran.

abstract: M.A.Sc.


title: Mode I Fracture Testing on Zirconium Foils Under Plane-stress Condition

contributor:
Daymond, Mark
Mechanical and Materials Engineering

subject: Fracture Zirconium DIC GND crack

abstract:
Zirconium alloys are commonly used in nuclear reactor in-core components due to their good mechanical properties and low neutron-absorption cross-section. Especially for CANada Deuterium Uranium (CANDU) reactors, zirconium alloys serve as the main structural material for fuel channels. In order to ensure such Zr components operate safely, fracture analysis of Zr alloys has been widely studied. Considering the high cost and difficulties associated with using neutron-irradiated Zr specimens for fracture analysis, proton irradiated testing has been proposed to reduce the cost and maintain a good control of experimental conditions during irradiation. However, limited by the proton penetration depth, fracture testing on proton-irradiated samples needs to be conducted on thin foils which brings increased plastic deformation due to the low constraint.  This dissertation mainly focuses on conducting fracture testing with Zr foils. Combined with finite element modeling, scanning electron microscopy analysis, and digital image correlation analysis, the fracture behavior at a crack tip from both macroscopic strain analysis and microscopic dislocation motion analysis was achieved.
The current study is comprised of three manuscript chapters. The Mode I fracture testing of Zr foils under plane-stress conditions is discussed in Chapter 3. Using conventional fracture testing combined with digital image correlation analysis, the J-integral, J-resistance curves and the singular strain field in front of a crack were all obtained. In Chapter 4, the dislocation evolution at the crack-tip field was analyzed during the crack initiation and propagation stages from a microscopic perspective. Both fracture toughness J-integral analysis and geometrically necessary dislocation determination indicate a single J-integral characterized crack-tip field may exist in Zr foils regardless of the large scale yielding condition. The crack propagation behavior was investigated from a crystallographic view in Chapter 5. Schmid factor analysis were compared with the geometrically necessary dislocation determination and relatively good agreement was observed. It was found that the crack is more likely to propagate along grains with c-axis close to the loading axis. A general discussion is given in Chapter 6, followed by a summary in Chapter 7.

abstract: PhD