VictorJuiz/thesis huggingface dataset:
Metallic NanoPorous Materials, from Design to Degradation

From (bio)sensing to self-powered wearable electronics, nanomaterials have showed great potentials in empowering the march towards sustainability. The theory, synthesis, characterization, and degradation of metallic nanoporous materials, of particular nanoporous gold, due to its versatility and biocompatibility, and nanoporous copper, due to its extraordinary catalytic and self-sanitizing properties, are discussed. Nanoporous gold was designed and synthesized by electrochemical dealloying from lean noble alloys (silver-gold(-platinum)) with the minimum gold content theoretically sufficient for the development of a fully gold covered nanoporous morphology. Advanced characterization techniques, such as atom probe tomography, were employed to obtain a near atomic-scale resolution of the nanoporous morphology developed from Ag95Au5, the lowest gold content precursor to date. The capabilities and drawbacks of atom probe tomography in characterizing heterogeneous nanomaterials were explored. A non-destructive and inexpensive electrochemical characterization technique was developed to probe the chemistry of the entire surface of such tortuous morphology. Via sulfide selective adsorption on silver, the surface chemistry of nanoporous gold was characterized with a precision of approximately 2 atomic % silver coverage on the outermost monolayer. Mechanical integrity of nanoporous layers developed from lean noble alloys was investigated using a combination of ex situ and in situ microscopy, as well as image processing algorithms. Despite speculations in the literature, capillary stresses during drying of the nanoporous samples was found to have no correlation with crack formation within the dealloyed films. Cracking within the nanoporous layers was analyzed by obtaining crystallographic information from cross-sections of the dealloyed samples. Coarsening behavior of nanoporous gold samples developed from various noble precursors was also studied in different media for long exposure times (up to a few months). Alloying with elements with low surface diffusion coefficients (e.g., platinum) was found to decrease the post-porosity coarsening rate, as also demonstrated in several previous investigations. However, under anodic polarization, platinum containing samples exhibited almost identical coarsening behavior to that of dealloyed binary silver-gold samples. Lastly, the applications of nanoporous copper developed via (electro)chemical techniques in self-sanitizing and catalytic electroreduction of CO2 were reviewed. Additionally, investigations were performed to synthesize nanoporous copper via guided dezincification of brass, a prevalent and inexpensive copper alloy.

Keywords: coarsening
dealloying
electrocatalysis
electrochemistry
nanoporous copper
nanoporous gold
Advisor: Newman, Roger RCN
Development of Low-cost Seismic Isolation Platform (SIP) for Mass Implementation in Developing Countries

Rapid urbanization of densely populated cities in developing countries like India has exposed large areas to greater human and economic catastrophes caused by natural disasters, specifically earthquake and flooding. This highlights the global need for the development of affordable, yet robust and resilient housing against such natural disasters in these regions. This research proposes a novel system, namely the Seismic Isolation Platform (SIP), for the mass implementation of low-cost seismically resilient systems for commonly designed affordable housing in densely populated and seismically active urban regions in India. The SIP system consists of three major portions including a supporting slab, low-cost seismic isolation layer, and ground floor columns. The isolation layer within the SIP consists of flat sliding bearings which are comprised of a low-cost off-the-shelf commercially available material sliding on a flat sheet of stainless steel.Large-scale component level testing is used to identify and characterize friction properties of a number of potential low-cost sliding interfaces that have not been studied extensively as seismic isolation sliding surfaces in prior research. Based on this investigation, high density polyethylene (HDPE) in contact with polished stainless steel is selected as the most economical viable sliding system for the SIP. Using the experimental data, modifications to an existing mathematical friction model are proposed to consider the variation of the breakaway friction with initial sliding velocity and the transition between breakaway/stick-slip and dynamic friction. Two post-tensioned transfer systems are studied for the SIP supporting slab using a regular ten-storey and an irregular twenty-storey RC building that were designed as per most recent Indian standards were. Lastly, the seismic performance of the SIP with and without two proposed low-cost displacement restraining systems was numerically validated using two reference ten-storey benchmark buildings. Results of extensive nonlinear dynamic analyses showed that the proposed SIP, combined with a low-cost displacement restraining system is efficient to minimize the structural damage of a building that is designed conventionally for a lower hazard level, but located in a high seismic zone, to a point where the structure could resume its function almost immediately after a severe seismic event.

Advisor: Christopoulos, Constantin
Assessing the Validity and Reliability of using One Inertial Measurement Unit to Measure Wheelchair Kinematics on Elite Wheelchair Court Sport Athlete

The measure of wheelchair speed and rotation (kinematics), using Inertial Measurement Units (IMU) can help athletes, coaches and practitioners identify important training paradigms in wheelchair court sports. However, there are several different IMU algorithms currently used. One of these algorithms uses three IMU (3IMU), and is considered the “gold standard” for measurements in the field. It has shown high levels of validity in field testing and incorporates methods to handle common errors, but the cost of outfitting an athlete with three sensor may limit sports from using this technology. An algorithm that uses only one IMU (1IMU) placed on the wheel hub of a wheelchair, and uses the Madgwick filter to measure the orientation the sensor, has been developed to measure the speed and rotation of the chair. While some preliminary validation work on 1IMU outputs has been promising, this algorithm not been rigorously tested. However, if this algorithm proves to be reliable and valid, the cost of measuring wheelchair kinematics for a whole team becomes substantially less. The purpose of this investigation was to further assess the ability of 1IMU to accurately and reliability measure continuous and discrete kinematic data, during basic movement patterns in wheelchair court sports. Elite wheelchair basketball and wheelchair rugby players were recruited, and they performed maximal sprint and agility tests. The validity and the reliability of the 1IMU outputs were measured and compared to 3IMU as well as timing gates and video. Further, the impact on these kinematic outputs because of poor measurements in wheel sizes as a reduction in sampling rates from 200Hz to 25Hz was evaluated. It was determined that 1IMU provides good to excellent levels of agreement with 3IMU and video for most kinematic data. Further, it was determined that sampling rates of 100Hz should be used to ensure that kinematic metrics defining peak linear and rotational speeds are preserved. However, it was also determined that further investigations are required to generate more accurate data for linear speed during turns. Overall, it is recommended that 1IMU can be used in testing protocols to measure wheelchair kinematics.

Advisor: Thomas, Scott
Architecting Enterprise Capabilities using a Socio-technical Modeling Framework

Information systems and software design are at the center of enterprise strategies as organizations face rapid changes in a global environment. Information systems and digital experiences nowadays play a prominent role in enterprise competitiveness. To this end, researchers and practitioners have built on the concept of capability to analyze what a business can and should do to fulfill its strategic trajectories and design information systems. This research builds on the notion of capability to enable co-design of software and business by representing and analyzing evolution strategies while considering the organization's social and technical needs.The thesis presents research on the development, demonstration, and evaluation of a conceptual modeling framework named ArchCap. It consists of meta-models, methods, guidelines, instantiations, and analysis techniques. An agent-oriented modeling paradigm is adopted to capture social and technical aspects of decisions with the ability to analyze and cater for enterprise-specific characteristics. ArchCap includes a conceptual foundation layer including meta-models, modeling rules, and guidelines to explicate (1) why a capability is needed, (2) how it is achieved, (3) how it fits within the organizational and social setting of the enterprise, and (4) what relationships are required for its success. The analysis layer of ArchCap presents techniques to perform (1) qualitative evaluation, (2) capture different kinds of capability choices, and (3) identify flexibility needs and possible causes of inflexibilities. These components build on research and theories in strategic management and systems thinking to ensure any design can adapt to changing conditions and continuously evolving strategies. The process layer of ArchCap provides a set of repeatable instructions, guidelines, and techniques to enable requirements engineers to leverage the framework. The thesis demonstrates the framework's usability and its research artifacts through its instantiations and two empirical case studies. The success of using the concept of capability and the integrative role of the proposed modeling framework in depicting social and technical requirements were at the center of the empirical research. The analysis techniques of ArchCap were successful in evaluating a particular strategy (consisting of many capability alternatives) and informed decision-makers in these organizations.

Keywords: Conceptual Modeling
Dynamic Capability
Enterprise Modeling
Requirements Engineering
Software Architecture
Advisor: Yu, Eric
An Anti-cytokine Agent for Anhedonia: Investigating the Immune-inflammatory System as a Therapeutic Target for Dimensional Disturbances in Mood Disorders

Patients with depression are conventionally treated with the assumption that a treatment will be broadly effective across multiple dimensions. However, depression is a heterogeneous clinical syndrome that is subserved by multiple convergent and divergent disease processes. Data-driven and ecologically valid phenotypes of phenomenology are needed to parse the heterogenous etiology of depression. Moreover, mechanism-of-action studies should target domain-based pathology with mechanistically plausible treatments and aim to inform disease models.The thesis herein investigated the immune system as a putative therapeutic target for anhedonia, a transdiagnostic, yet specific, and clinically relevant symptom dimension. Anhedonia represents a disturbance in reward- and motivation-related neurobiological processes and is characterized by a diminished ability to enjoy previously enjoyable activities. Brain circuits, nodes, and networks, as well as cellular and molecular pathways (eg dopaminergic transmission, excitotoxicity, synaptic plasticity), subserving anhedonia are preferentially affected by inflammatory processes. Hitherto, no curative treatments have been identified or developed for the treatment of anhedonia. Infliximab, an anti-inflammatory agent that specifically targets tumour necrosis factor-α signalling, reduced anhedonic symptoms in a randomized, double-blinded, placebo-controlled clinical trial. Furthermore, we identified a data-driven inflammatory biotype of adults with bipolar depression who were more likely to derive anti-anhedonic benefit from infliximab. We provide a framework for conceptualizing the therapeutic and mechanistic relevance of the TNF-α signalling pathways in the treatment of anhedonia. Taken together, our findings instantiate the relevance of inflammatory processes and the immune system in the phenomenology and etiology of mood disorders and provide the impetus to develop scalable treatments targeting the immune system to mitigate transdiagnostic, dimensional disturbances (eg anhedonia). A domain-based approach to drug discovery and development, informed by an understanding of disease processes, is needed to target brain-based pathology. Future studies investigating viable anti-anhedonic treatment avenues should demonstrate target engagement in neural systems subserving reward learning and valuation (eg cognition, habit formation), as well as reward-motivated behaviours (eg seeking, consummatory).

Keywords: biomarkers
Bipolar Disorder
Depression
Machine learning
Mood Disorders
psychiatry
Advisor: McIntyre, Roger S
Gravitational Wave Echoes: Theory and Application

Black hole mimickers may compose some of what is assumed as the black hole population, and multiple groups have claimed evidence for this in the form of gravitational wave echoes. This thesis elaborates on work by the author and collaborators, detailing echo theory and discussing hints of echoes in gravitational wave data from the LIGO observatory.Echoes from a variety of exotic compact objects are compared, and the effects of spin are investigated. The most characteristic feature of echoes, a series of spectral resonances, is exploited to look for this structure in LIGO data via windowing methods. These resonances are modulated by an initial-condition-dependent source integral, and it is shown that echo features traditionally assumed to be known may be altered by generic production mechanisms. The complete modulation in all variables is calculated, and the impact on echoes is displayed. An analytical method is constructed to test asymptotic radial perturbations. Quantum quadratic gravity is a theory capable of producing echoes, and it can be made renormalizable with ultraviolet completions. It may also satisfy the optical theorem under certain conditions, and these are reviewed and further explored through two subjects: the physical particle spectrum and the complex prescription of propagators. Required conditions for unitarity are defined along with their consequences, and the consistency of the theory is tested against these. The search for echoes is then continued in a recently detected gravitational wave event, GW190521, by employing the latest developments in echo theory. Combining advancements in physical boundary conditions, numerical relativity, and complex representation of the echo spectrum, a model is built to seek for physically motivated echoes across background parameters of mass, spin, and geometry. The search is done over Monte Carlo chains distributed according to background parameter probabilities, with significance assessed by signal to noise ratios and statistical analysis. Potential echo detections in the LIGO events GW151226, GW170104, GW170608, GW170814, and GW170817 are presented with false alarm rates of 1 in 700 or less using the older windowing methods. The latest model is employed to find a false alarm rate of 1 in 50 in GW190521.

Keywords: black holes
echoes
gravity
quantum
Advisor: Holdom, Bob
Teachers' Use of Discourse to Promote Student Learning in Grade 7 and 8 Mathematics

The study investigates how teachers use math discourse in grade 7 and 8 math classrooms. Teaching strategies that use student interaction combine with the natural desire to communicate with teaching. The way teachers interact with their students can increase or decrease their students’ level of participation and engagement and eventual learning of mathematics. The study uses a multiple-case methodology and involves four participants. Data were collected from each participant using two semi structured interviews, two observation sessions, publicly maintained websites and using the researcher’s journal. Each case was analysed separately for major themes and then a cross case analysis was conducted to find similarities and commonalities among the cases. The five major findings of the study are: (1) teachers prepare their students to work in groups of three to four students by doing several activities prior to start engaging them in discourse; (2) teachers nurture a conducive classroom learning environment prior to engaging students in discourse; (3) teachers with good knowledge of mathematics, the curriculum, pedagogical practices, and with extensive teaching experience tend to have more success with using discourse to promote student learning; (4) teachers use focused questioning to help students during math lessons; and (5) teachers improve the level of students participation by using several strategies.

Keywords: adolescent teaching
classroom environment
cooperative learning
mathematical discourse
teacher education
teacher knowledge
Advisor: McDougall, Douglas
Contextualizing Medicine and its Roles in Seventeenth-century Tibet

This dissertation examines Tibetan medicine and its roles in Tibetan politics and culture throughout history with a focus on the seventeenth-century and the reign of the Fifth Dalai Lama (1617-1682) and his last regent, Desi Sanggyé Gyatso (1653-1705). It explores the role that their patronage of medical institutions, scholarship, and practice played in legitimizing the rule of their new regime and in helping to establish Lhasa as the capital of Tibet. It critically examines how modern scholars have approached the study of Tibetan medical history through a comparative approach with European medical history, arguing that applying ideas and periodizations from the latter onto the former is methodologically unsound. It suggests alternative approaches to the study of Tibetan medical history, including different ways to engage with Tibetan historiography and how we might begin to think about the roles of non-human actors, such as deities, in Tibetan history and medicine.

Keywords: History of Medicine
History of Tibetan Medicine
Tibet
Tibetan Medicine
Advisor: Garrett, Frances
Temporal Gait Asymmetry: The Relationship of Rhythm Abilities, Perception of Performance, and Responsiveness to Rhythmic Auditory Stimulation

A promising intervention to target persistent post-stroke temporal gait asymmetry (TGA) is rhythmic auditory stimulation (RAS). Response to this intervention likely depends on the influence of many patient-related factors. This thesis examined the influence of two such factors on the relationship between TGA and the immediate response to RAS: rhythm ability and perception of gait performance. This thesis is comprised of four studies that investigated perception of an induced TGA in healthy adults, the effect of rhythm ability on the response to RAS with an induced TGA and with post-stroke TGA, and the influence of RAS on TGA perception. A unilateral load induces TGA in neurotypical adults, however accurately perceiving this asymmetry may be a difficult task, as nearly half of participants incorrectly perceive the direction of their asymmetry (study 1). Conversely, people with stroke are mostly accurate at detecting the presence and direction of their TGA (study 4). Both healthy adults and individuals with stroke improve TGA regardless of rhythm ability (study 2 3). Healthy adults with strong rhythm ability demonstrate greater step synchronization to the beat than those with poor ability, though this did not affect the response to RAS (study 2). Some individuals with stroke who worsen TGA with RAS have significantly poorer rhythm ability (study 3). For both healthy adults and people with stroke, walking to a metronome reduces the ability to detect the presence of TGA (study 4). This thesis presents new evidence for the relationship between rhythm abilities, the perception of TGA, and the responsiveness of TGA to RAS. Since some individuals with poor rhythm ability worsen TGA with RAS, clinicians may consider assessing individual rhythm ability when using rhythm-based treatments. The disparate ability to accurately perceive TGA among study participants demonstrates the importance to provide augmented feedback in therapy for interventions that rely on the perception of performance. Future work should explore the influence of rhythm ability on the response of TGA to other auditory stimuli (e.g., music) or the effect of rhythm ability on the response to a RAS intervention and consider alternate approaches to assess the perception of gait performance.

Keywords: asymmetry
gait
perception
rhythm
stroke
Advisor: Patterson, Kara K
Ageing Among Off-reserve Indigenous Populations in Canada

Indigenous populations in Canada experience ageing differently than non-Indigenous populations. The intergenerational effects of colonization on Indigenous Peoples’ health combined with Indigenous populations’ holistic approach to health and ageing warrant the need for Indigenous-specific ageing research. In the past decade there has been an increased focus on Indigenous-specific ageing research. However, there remain many areas of ageing research to be explored. In this thesis, Indigenous and epidemiologic research methods were utilized in combination with a community-engaged approach to fill some of these research gaps. This is the first study to investigate both the physical and emotional health aspects of ageing for off-reserve Indigenous populations in Canada. I collaborated with a Community Advisory Board to develop research questions relevant to Indigenous Peoples, inform my data analysis plan to produce meaningful results and to use Indigenous perspectives to interpret the research findings. Data from the Canadian Community Health Survey were used to estimate the prevalence of and factors associated with frailty among off-reserve Indigenous populations ≥45 years of age. The same survey data was used to study ageing from a more holistic approach by investigating life satisfaction as a measure of successful ageing. The prevalence of frailty was approximately 18% for Indigenous men and 20% for Indigenous women. The age- and sex-adjusted prevalence estimates were higher for both Indigenous men and women compared to non-Indigenous men and women. Although the prevalence of frailty was high for Indigenous populations, 90% of Indigenous people included in this study reported high levels of life satisfaction. A strong sense of community belonging, and physical activity were associated with lower levels of frailty and higher levels of life satisfaction. Recommendations were made based on the findings for community-led policies and programs to promote healthy ageing through access to culturally appropriate health services, land-based exercise programs and facilitating connections between older Indigenous people and their community. In addition to the quantitative research findings, the unique methodology used in this thesis may serve as a guide to approach future Indigenous epidemiological studies, an area that has received little research attention to date.

Advisor: Rosella, Laura
Walker, Jennifer