title: Distributed Sensing for Monitoring Cast Iron Pipe Behaviour

contributor:
Hoult, Neil
Moore, Ian
Civil Engineering

subject:
Cast Iron
Pipe
Distributed Sensing
Fibre Optics
Differential Ground Movement
Frost Heave
Four-Point Bending
Parallel Plate Loading

abstract:
The objectives of this thesis were to investigate the material performance and field behaviour of small diameter cast iron water pipes. Exhumed pipes were provided by the Cities of Kingston, Hamilton, and Toronto in Canada. Four of these 150 mm diameter pipe specimens, with a length of 2.2 m, were instrumented with distributed fibre optic sensors (three circumferential fibres around midspan and five longitudinal fibres along the crown, springlines, and invert) and tested in four-point bending to identify the circumferential and longitudinal strain distributions before failure. Additionally, 48 parallel plate loading tests were conducted on 25- and 100-mm ring samples to identify the variation in behaviour over the length of a pipe specimen. Samples from both tests exhibited linear strain patterns up to 50% of ultimate load, after which the strains increased non-linearly with load. In parallel-plate loading, the ring specimens generally sustained more load when the wall thickness at the failure location was larger. In bending, peak tensile hoop strains at midspan occurred at the crown while compressive strains occurred below the springlines down to the invert due to Poisson’s effects. The pipes under four-point bending did not fail at locations of observed peak tensile strain, indicating that cast iron pipes can fail at locations without physical signs of deterioration or damage.
A field study of two sites in Kingston, Ontario was conducted to investigate the relationship between pipe leakage and differential ground movements. Seasonal ground movements were monitored using total station and Light Detection and Ranging (LiDAR) surveying equipment. Ground movements of 23 to 30 mm were detected from a roadway repair required to fix a water main break, suggesting that both technologies are capable of detecting ground movement of this magnitude. Additionally, the LiDAR results indicated ground movements of 25 to 30 mm around a confirmed leak, however it was difficult to distinguish this area versus noise in the data set. The total station data was able to confirm the profile of the ground movement but not the magnitude (due to conflicting signs) around the confirmed leak.

abstract: M.A.Sc.


title: Mean Squared Error For Optimal Designs in the Polynomial and Spline Regression

contributor:
Levit, Boris
Mathematics and Statistics

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:
Optimal Design
Statistics
Nonparametric Regression

abstract:
This thesis aims to further expand the existing optimal design theory for polynomial and spline regression models. We will show that the classical minimax design in polynomial regression models leads to the recently introduced stronger notion of R-optimality.
Furthermore, we aim to clarify the notion of optimal design theory for spline regression models. We will describe various types of cardinal splines and discuss related to them various theorems within the context of optimal design.

abstract: M.Sc.


title: Development and Influence of Erosion Voids at Rigid Pipe Joints

contributor:
Moore, Ian D.
Hoult, Neil A.
Civil Engineering

subject:
Rigid Pipes
Buried Pipes
Reinforced Concrete Pipes
Erosion
Erosion Voids
Deep Burial Facility
Distributed Fibre Optics

abstract: An experiment was designed and conducted to study the effect that erosion voids forming at leaky reinforced concrete pipe joints have on the pipe response to surface loading. The experiment consisted of a jointed system of two 825 mm inner diameter reinforced concrete pipes, buried in a uniform sand. A section of the pipe joint was left unsealed to allow infiltration once the water table was raised to the ground surface. Circumferential strain profiles on the inner and outer wall of the pipe were measured using nylon fibre optics. The strains were then used to calculate the moment and thrust response of the pipe during service load testing. Each stage of the erosion void growth experiment had an initial surge of sand ingress, which then slowed to a low energy flow that carried little to no eroded soil into the pipe. The total dry mass of eroded soil collected through the erosion void growth was approximately 33 kg, which had a volume of around 20 L. The final void geometry was thin, with a thickness ranging from 5 to 20 mm, and widely spread along the pipe system, with maximum vertical and horizontal extents of 0.95 m and 1.12 m, respectively. Gel-encased fibre optics along the outer pipe wall along with a heat source were used to attempt to track the extent of the void contact along the pipe during erosion, but results were inconclusive. Similar to prior analyses and testing conducted with artificial erosion voids, an increase in moment occurred due to the soil support lost in the location of the erosion void. When the service loads were applied over the joint of the pipe system, higher responses to load were recorded in the bell pipe than the spigot pipe. This may be a function of the relative stiffness of the bell compared to the spigot, as well as additional lost bedding support lowering soil pressure on the spigot pipe. More tensile thrusts were also measured in the spigot pipe during post-erosion void load testing. Polymer filler injected into the void was not observed to affect pipe response.

abstract: M.A.Sc.


title: Force-free Plasma Equilibria and Differential Operators Connecting Certain Equations

contributor:
Bogoyavlenskij, Oleg
Mathematics and Statistics

subject:
Grad--Shafranov equation
Klein--Gordon equation
Helmholtz equation
Differential Operators
Exact Solutions

abstract: Differential operators connecting a linear case of the Grad--Shafranov equation and the axisymmetric Klein--Gordon equation are found. Differential operators linking another linear case of the Grad--Shafranov equation and the axisymmetric Helmholtz equation are also given. Infinite families of exact solutions to the Grad--Shafranov equation of both types and their corresponding force-free plasma equilibria are derived. General constructions of transforms among differential equations are presented.

abstract: M.Sc.


title: Multitaper Statistical Tests for the Detection of Frequency-Modulated Signals

contributor:
Takahara, Glen
Burr, Wesley
Mathematics and Statistics

subject:
Multitaper
Frequency Modulation
Hypothesis Testing
Polynomials

abstract:
Detection of periodic signals in noise is an important problem in many scientific fields and there exist tools in the multitaper spectrum estimation and harmonic analysis framework for doing so, for example, the Harmonic F statistic. However, the Harmonic F statistic can lose effectiveness under certain types of frequency modulation, when the signal to noise ratio is low, and when the background spectrum is highly coloured. In his 2009 paper, "Polynomial Phase Demodulation in Multitaper Analysis," Thomson proposed methods for dealing with time series data (specifically, solar data) where these problems are present. In this thesis we propose an extension of this work to deal with the detection of frequency modulated signals. The method uses the Slepian sequences as projection filters to reconstruct the series based on a 2W band around a given carrier frequency and then tests the
instantaneous frequency series for a low-degree polynomial form in that band using the Slepians combined with an associated family of polynomials in a variance ratio test statistic. Under the null hypothesis that there are no sinusoidal signals with polynomial frequency modulation at the given carrier frequency, these test statistics are approximately distributed according to an F distribution with degrees of freedom depending on the number of tapers used and the degree of the polynomial being tested. We compare several such test statistics via simulation studies and apply them
to a solar time series from the GOLF SoHO instrument.

abstract: M.Sc.


title: A Story of Storytelling: Listening to Narratives of Belonging within the Indigenous Art Centre

contributor:
Vorano, Norman
Cultural Studies

subject:
Indigenous Art
Decolonial Praxis
Arts Management
Institutional Ethnography

abstract:
The Indigenous Art Centre (IAC) is an Indigenous-led federal program that supports “the creation, preservation and promotion of contemporary art produced by Indigenous peoples in Canada.”  Presently, the Indigenous Art Collection, around which the Centre is based, encompasses upwards of 4300 artworks produced by First Nations, Metis and Inuit artists dating from the 1950s to the present. Maintained by the Canadian federal department of Crown-Indigenous Relations and Northern Affairs Canada (CIRNAC), the Centre is acknowledged by members of the Indigenous arts community as one of the most comprehensive overviews of the contemporary Indigenous art movement in Canada.   The Collection is concomitantly endorsed by the federal government as an historically and culturally significant national heritage collection.
The study explores the operational significance of the federal program, in the wake of Canada’s ratification of the United National Declaration on the Rights of Indigenous Peoples (UNDRIP) in 2016, the release of the Truth and Reconciliation Commission of Canada (TRC) Calls to Action in 2015 precipitating in federal policy shifts and the creation of social infrastructure supports. Through personal accounts from facilitators/receivers of the Centre’s programming, the Indigenous-led management of the Collection is explored. The investigation navigates the institutional processes via individual experiences. Imperatives of ethical responsibility and reciprocal engagement are used as guiding markers. The study generates conversation within and recognition for the unique model of collaborative arts management practiced within the Centre.

abstract: M.A.


title: Examinations of the Labour Market Outcomes and Housing of Ontario Social Assistance Recipients

contributor:
Cotton, Christopher
Economics

subject:
Labour
Economics
Social Assistance
Immigrant
Homelessness
Labour Market Program
Poverty
Welfare
Public Policy
Unemployment
Residential Mobility

abstract: This thesis showcases a series of research examining various aspects of social assistance programs and their recipients using a set of administrative microdata following beneficiaries of the social assistance programs in Ontario, Canada. In Chapter 2, an analysis is carried out examining the disparities between various labour market outcomes for immigrant and non-immigrant social assistance recipients. After controlling for education level and other characteristics, survival analysis shows that likelihood of immigrant recipients exiting social assistance in any given period is statistically significantly lower than that of non-immigrant recipients by around 16%. However, further analysis reveals that immigrant recipients are less likely than non-immigrant recipients to return to social assistance after leaving. This discrepancy between the likelihood of finding employment and the implicit likelihood of retaining employment may be evidence of discrimination faced by immigrants in the Ontario labour market. Within the immigrant portion of the sample, higher age at their time of arrival to Canada leads to lower likelihood of finding employment, but lower likelihood of returning to social assistance, which could point to issues of cultural assimilation or discrimination against immigrants in the hiring process, or the undervaluation of human capital attained outside of Canada. Chapter 3 focuses on active labour market programs to which Ontario Works social assistance beneficiaries are assigned, intended to help them find and keep employment. After controlling for endogenous enrollment and omitted variable bias using an instrumental variable approach, significant differential impacts are found on unemployment spell duration, return rates to social assistance, and future time spent on social assistance across programs.  Additionally, the effects of programs when assigned simultaneously are found to be detrimental. Chapter 4 provides a descriptive analysis of the housing situations and levels of residential mobility among recipients of Ontario Works, as well as the Ontario Disability Support Program. Additionally, an examination of those experiencing homelessness while on social assistance is carried out to examine prevalence of homelessness among different subpopulations. Overall, this research aims to shed light on both the living situations and labour market experiences facing those who are the most economically vulnerable in our society.

abstract: PhD


title: Investigating the Neural Basis of Pain Sensitivity in Fibromyalgia Using Functional Magnetic Resonance Imaging

contributor:
Stroman, Patrick
Neuroscience Studies

subject: fMRI Pain Fibromyalgia Human

abstract:
Fibromyalgia (FM) is a chronic pain condition that is estimated to affect 2-5% of the global population. The cause of FM is currently unknown, although most evidence suggests it involves central sensitization. To determine the underlying neurological mechanism of this central sensitization, researchers have started to study pain processing in people with FM using functional magnetic resonance imaging (fMRI). The results from these studies have been inconsistent and appear to be related to the fMRI analysis method that is used. Model-driven analysis methods have consistently identified little to no differences in neurophysiological activity associated with pain processing between healthy and FM study groups. On the other hand, data-driven methods have consistently identified differences between the two study groups. The overall aim of this thesis was to determine if data-driven analysis methods provide information about pain processing that model-driven methods do not, and to use a data-driven method to improve our understanding of the possible mechanisms underlying central sensitization in FM.
For the first objective, a model-driven and a data-driven analysis method were compared by analyzing datasets from two separate fMRI pain studies involving healthy controls and participants with FM. The results from this comparison were consistent with what has already been reported—that is, the model-driven analyses did not identify differences in pain processing between the two study groups, and the data-driven analyses did. To improve our understanding of the neural basis of pain sensitivity in FM, healthy controls and participants with FM were subjected to an identical ‘threat/safety’ fMRI paradigm, and the results were analyzed with the same data-driven method. Differences in brain activity between the two study groups were identified. Furthermore, the FM-specific brain activity suggests that central sensitization in FM is likely associated with dysfunctions in brain regions involved in the motivational-affective aspects of pain processing. These results emphasize the importance of data-driven analyses when studying pain processing and highlight aspects of pain processing specific to FM that deserve further investigation.

abstract: M.Sc.


title: Phase Shift, Duty Cycle and variable Frequency Control of a Full-Bridge DC-DC Converter for Two Solar PV Panels

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

subject:
Power Electronics
DC-DC Converter
Solar PV Applications
Phase Shift and Duty Cycle Control
Full-Bridge Converter
Soft-switching

abstract:
Renewable energy resources are becoming the future of power generation with a particular focus on harvesting the solar energy found in abundance on earth’s surface. Different power converter topologies are used for energy conversion that allow PV’s to connect in different configurations for the transfer of power. Differential power processing (DPP) has the advantage of high efficiency, but the limitation of such architectures exist in the complexity of operation with the increasing number of PV panels.

This thesis presents a novel DC-DC converter topology for multiple PV panels. The proposed topology provides an individual maximum power point tracking (MPPT) of the series connected PV panels by a differential current path introduced by an auxiliary inductor. The MPPT of the PV panels is achieved by controlling the three converter parameters: phase shift control to regulate the panel PV1 voltage, duty cycle to control the differential current through the auxiliary inductor, and lastly the control of converter’s switching frequency for increased efficiency under light mismatch condition of the PV panels. Controlling the differential current of the auxiliary inductor, also helps in achieving ZVS for the entire load
range and eliminates the need for any additional active switches to achieve MPPT for the PV panels. Thus, the simple structure and the ability to achieve ZVS of the proposed topology make it an excellent and cost-effective solution for high frequency solar applications.

abstract: M.A.Sc.


title: Rethinking Extraction: A Lefebvrian Critique of Sustainable Mining Discourse

contributor:
Smith, Michael
Environmental Studies

subject:
Henri Lefebvre
Sustainability
Mining
Extraction
Space
Extractivism
Unliveable Space
Space of Death
Alternative Spaces

abstract: The idea of Sustainable Mining (SM) has gained increasing traction in the past two decades as an industry-based response to concerns over operational pollution, the (mis)treatment of local/Indigenous communities, and a growing awareness of diminishing and finite mineral stocks. Corporate Social Responsibility (CSR) is currently the theory of choice for thinking about and implementing change at the industrial level, however, this thesis argues that Henri Lefebvre’s theory of the production of space illuminates the serious limitations of such approaches. Lefebvre challenges the dominant modern understanding of space as a neutral, passive, empty container arguing that it is a socially produced realization of particular modes of spatial production. Every society produces its own space, which facilitates and constrains different forms of life. CSR remains mired in that abstract and reductive spatialization exemplified by extractive processes that have made, and continue to make, spaces unliveable for thousands of communities around the world. I suggest Lefebvre’s work offers a quite different way of thinking about sustainability itself, not as an abstract balancing act between three distinct pillars – economy, society, environment, but in terms of how these are, in actuality, always already combined together in and through different modes of spatial production. The focus of sustainability then becomes one of producing and reproducing continually livable spaces, rather than ensuring economic growth.

abstract: M.E.S.


title: Challenges of Black and Other Minority Students Around Equity and Inclusion in a Postsecondary Institution in Ontario, Canada

contributor:
Butler, Alana
Education

subject: Black and minority students, challenges, diversity, equity, inclusion, relationships, support, identity

abstract: In Canada statistics show that visible minorities represent 23.3% of the total Canadian population. The vast majority (94.8%) of the foreign-born population lives in Ontario (53.3%), British Columbia, Quebec, and Alberta. Also, in 2016 Africa ranks second as a source of newcomers in Canada representing 13.4% of the share between 2011 and 2016. This study investigates the challenges of this minority population around equity and inclusion at a post secondary institution in Ontario, Canada. Minority students are constituted of Black (African and Caribbean), Middle Eastern, Mixed, Latin, South Asian, Chinese, and Indigenous communities. Stratified sampling was used to distinguish Black students from other minority students. Black students were further stratified into Caribbean and African with the final level of stratification being the ancestral country of origin. This research used a mix method to collect quantitative and qualitative data. The survey was conducted on 132 participants coming from a post secondary institution in Ontario. Among these students, 7 accepted to take part in the interview for this study and referred 3 other minority students. In total 10 minority students (7 undergraduate and 3 graduates; 5 domestic and 5 international) participated to the interview of this study. Black students faced more challenges than other minority students around equity and inclusion. Minority students faced socio-economic challenges due to high tuition fees (international students), racial discrimination, and racial micro-aggressions. Homophily with subtle segregation was the type of relationships prevalent between Black, non-White, and White students. Systemic racism prevailed characterised by a macroaggression policy that took 100 years to grant an apology to afflicted Black students without accompanying measures. This study recommends for better inclusion of minority students developing a culture of integration (both homophily and propinquity relationships), supporting apology for macroaggression policy with a special scholarship for Black students. This study also recommends the enhancement of equity by providing more opportunity to the White population to learn about multiculturalism, the increase in number of Black students, teachers and staff who are far less represented within the minority population and the introduction and promotion of more extracurricular opportunities that facilitate integration of minority students.

abstract: M.Ed.


title: Force-Based Control of UGVs by Using Physical Human-Robot Interaction

contributor:
Marshall, Joshua
Surgenor, Brian
Mechanical and Materials Engineering

subject:
Human-robot interaction
Unmanned ground vehicles
Admittance control
Force sensors
Force-based control

abstract:
Humans apply directional forces to move wheeled objects in various everyday applications such as maneuvering a loaded cart, a lawnmower, or moving a stretcher. The heavier the object, the higher the magnitude of force required by the human to move it. This thesis proposes to use similar interactions on mobile robots to move bigger and heavier vehicles at the command of a human operator that physically pushes the vehicle. At the same time, the objective is to have the human operator perceive the vehicle as being much lighter to extend his/her ability when working with heavy loads.

A Husky A200 mobile robot, a differential drive robot by Clearpath Robotics, and Ibex, a custom-built land robot with four individually articulated tracks, were used to test the control system for such an interaction. A cantilever beam equipped with strain gauges and four FSRs were used to measure the forces applied by a human operator. For a natural motion, an admittance control model was used to generate velocity commands for the vehicle by using the measured forces as inputs. The preliminary design used a  fixed admittance model. After running experiments and analyzing the results, an adaptive admittance model was developed using Probabilistic Neural Networks to adaptively change the admittance parameters in response to a change in the operating surface environment.

abstract: M.A.Sc.


title: Robotic Assessment to Detect Neurological Impairments Associated with Transient Ischemic Attack

subject: cerebrovascular disease, stroke, robotics, cognition, sensorimotor, motor, motor system

abstract:
Transient ischemic attacks (TIA) are a substantial risk factor for ischemic stroke, but have been widely regarded as minor perturbations to the function of the central nervous system that leave little to no lasting impact on their own. However, in the last 20 years there has been a growing acceptance, that independent of increased risk of stroke, TIA can lead to neurological consequences that far outlast the previously prescribed symptom resolution window of 24 hours. The understanding of these deficits has been accelerated by the application of various technological approaches. Robotic assessment systems have been widely used to characterize neurological deficits arising from multiple sclerosis, Parkinson’s disease, and stroke. Their ability to measure motor behaviour precisely and reliably makes them ideal candidates to understand how TIA affects behaviour, and differs from other clinical conditions. In this thesis, the Kinarm robotic assessment system is used to characterize neurological deficits in people who have been diagnosed with TIA, and to understand how neurological deficits associated with TIA evolve over time.
The objectives of this thesis were to: 1) characterize neurological deficits associated with TIA, and 2) describe change over time in impairments associated with TIA. It was demonstrated that approximately one third of individuals diagnosed with TIA displayed unexpected deficits in tests of motor ability, and up to half displayed impairments on tests of cognitive-motor integration. One-class, machine learning was then used for detecting abnormal behavioural patterns, and the performance of this approach was compared to our approach of statistically aggregating Kinarm task variables. The one-class approach led to fair detection of abnormal behavioural patterns, with the best model performance shown in tasks testing cognitive-motor integration (area under the receiver operating characteristic ~ 0.65), similar to the previous approach. In order to lay the groundwork for characterizing change over time, a statistical framework was provided for capturing changes in Kinarm robotic assessment performance after repeat tests. Finally, it was demonstrated that in people diagnosed with TIA the evolution of behavioural ability displays varying patterns; approximately 1/10 had perseveration of motor- and cognitive impairments for up to 1 year beyond symptom resolution. Together, these findings suggest that TIA is associated with lasting neurological impairments. The approaches outlined in this thesis may help pave the way for the identification of sensitive and specific behavioural biomarkers that could assist with the detection of TIA in clinically relevant settings.

abstract: PhD


title: A PILOT STUDY: AN OPEN-LABEL BIOMARKER DEVELOPMENT OF KETAMINE FOR UNIPOLAR REFRACTORY DEPRESSION

contributor:
Vazquez, Gustavo
Neuroscience Studies

subject:
depression
ketamine
treatment-resistant depression
biomarker
BDNF

abstract: Objective: The primary objective of this study is to evaluate the antidepressant efficacy of an acute intravenous subanesthetic ketamine treatment (0.5 mg/kg) for patients with unipolar treatment-resistant depression (TRD). The secondary objective of this study is to identify peripheral blood-based biomarkers associated with response to treatment. Method: Fifteen adults diagnosed with TRD completed an open-label study of repeated infusions of low dose ketamine (0.5 mg/kg) over the course of four weeks. Blood was collected from eleven patients at three time points throughout the acute treatment to analyze peripheral biomarkers including irisin, IL-6, IL-10, TNF-α, and BDNF. Results: Repeated ketamine infusions produced a significant decrease in total average MADRS scores in fifteen patients with unipolar TRD [F(1, 14) = 49.06, p<0.01] at all timepoints. Improvements in depressive symptoms were significant at one-week [t(14)=9.32, p<0.01], and continued to significantly decrease until two-weeks [t(14)=2.27, p<0.05]. The antidepressant effect was maintained for the entire duration of treatment. Psychiatric symptoms measured by the BPRS significantly decreased throughout treatment, which correlated to the decrease in MADRS scores (r=0.99, p<0.01). Ketamine was generally well-tolerated, and we observed improvements in functional impairment and anhedonia with no increases in manic symptoms. Levels of BDNF throughout treatment significantly correlated to decreases in MADRS scores (r=-0.66, p<0.05), and baseline BDNF levels predicted mood response at one- [F(1, 10) = 12.23, p<0.01] and four-weeks [F(1, 10) = 9.55, p<0.05]. Conclusion: Repeated subanesthetic doses of ketamine infusions significantly improve depressive symptoms and produce sustained antidepressant effects over four weeks of treatment. Ketamine may be an efficacious and safe pharmacological option for the acute treatment of patients suffering from severe treatment-resistant depression, and BDNF has the potential to function as a prognostic biomarker for predicting response to ketamine treatments.

abstract: M.Sc.


title: A Bootstrapped Approach for Abusive Intent Detection in Social Media Content

contributor:
Skillicorn, David
Computing

subject:
natural language processing
intent detection
deep learning

abstract: The proliferation of Internet connected devices continues to result in the creation of massive collections of human generated content from websites such as social media. Unfortunately, some of these sites are used by criminal or terrorist organizations for recruitment or to spread rhetoric. By analyzing this content, it is possible to gain insights into the future actions of the writers. This information can support organizations in taking proactive measures to modify or stop said actions from taking place. The textual feature of interest is the expression of abusive intent, which can be thought of as a plan to carry out a malicious action. The proposed approach independently detects abuse and intent in documents, then computes a joint prediction for the document. Abusive language detection is a well-studied problem, which enabled a model to be trained using supervised learning. The intent detection model requires a semi-supervised technique since no labelled datasets exist. To do this, an initial collection of labels was generated using a linguistic model. These labels were then used to co-train a statistical and deep learning model. Using crowd-sourced labels, the abuse and intent models were found to have accuracies of 95% and 80%, respectively. The joint predictions were then used to prioritize documents for manual assessment.

abstract: M.Sc.


title: Exploring the Role Transition from Registered Nurse to Clinical Instructor: A Narrative Inquiry

contributor:
Luctkar-Flude, Marian
Nursing

subject:
narrative
narrative inquiry
clinical instructor
nursing education
clinical education

abstract: Administrators of nursing undergraduate degree programs are hiring adjunct faculty into clinical instructor roles to sustain clinical education in the midst of persistent nursing faculty shortages.  Despite being paramount to clinical education, limited literature exists from the perspective of clinical instructors.  The purpose of this narrative inquiry was to gain a deeper and richer understanding of the experience of transitioning into the clinical instructor role.  The study includes the individual stories of two clinical instructors who teach undergraduate nursing students in southern Ontario.  Data was collected through repeat interviews and interpretation was guided by the three dimensions of narrative inquiry space: time, social interaction, and place.  The data is presented in the form of retold narratives organized into individual chapters respective of each participant.  In attending to the individual accounts, common threads emerged across the two narratives.  The metaphor of learning to swim is used to describe the narrative threads of: 1) testing the water – I’m a nurse first; 2) thrown in the deep end – in way over my head; 3) coordinating strokes – all the other pieces that come along with it; and, 4) staying close to shore – clinical instruct on the side.  The narrative inquiry explores the role transition experience of nursing clinical instructors while preserving each individual story.

abstract: MNSc.


title: The Role of Muscarinic M2 and M3 Receptor Subtypes in Cardiopulmonary Responsiveness: Insights from In Vivo Murine Models

contributor:
Fisher, John T
Biomedical and Molecular Sciences

subject:
Murine Models
Airway Hyperresponsiveness
M3Dq DREADD
M3 Muscarininc Antagonists
Muscarinic Receptors

abstract: Muscarinic receptors play an important role in cholinergic transmission and physiologic events. However, the study of the mechanisms by which muscarinic receptors mediate cardiopulmonary responses have been hampered by the homology of the five muscarinic receptor subtypes. We pursued three distinct methodologic approaches using murine models to dissect the fundamental roles and mechanisms of muscarinic receptor subtypes M2 (M2R) and M3 (M3R) within integrative physiology. Firstly, the role of M2R and M3R was evaluated in the development of airway hyperresponsiveness (AHR) in ovalbumin sensitized murine models lacking functional M2Rs and M3Rs. We provide novel evidence that the M3R, but not M2R, was critical for allergen-induced AHR, based on respiratory mechanics during airway challenge. The lack of the M3R also resulted in an unexpected bronchoconstrictor hyperresponsive phenotype independent of OVA sensitization and inflammation. Next, we examined the cardiopulmonary impact of skeletal M3R (activation of Gq G-protein pathway) on thermoregulation and cardiopulmonary function in a muscarinic (M3Dq) Designer Receptor Exclusively Activated by Designer Drug (DREADD) model. Based on telemetry from freely behaving mice, skeletal M3Dq expression had no impact on the daily cardiopulmonary phenotype, whereas, activation of skeletal M3Dq by Clozapine N-Oxide elicited a phenotype characterized by reduced ventilation, heart rate and body temperature, consistent with a presumptive reduction in metabolism. Lastly, we tested the ability of two novel structure-based designed muscarinic antagonists, ABH 423 and JHH 378, to inhibit differentially, the M3R over the M2R in a C57BL/6 murine model. Both compounds demonstrated a 4,000 x or greater -fold in vivo selectivity (p<0.001) of the M3R over the M2R, which was reflected in the inhibition of methacholine-induced bronchoconstriction and preservation of methacholine-induced bradycardia. Our findings revealed: 1. the key role of muscarinic M3 receptors in the development of airway responsiveness, 2. the integrated cardiopulmonary response due to skeletal muscle M3Dq pathway activation, possibly linked to torpor and, 3. the first pre-clinical data for structure-based highly selective M3R antagonists with therapeutic potential for obstructive lung disease.

abstract: M.Sc.


title: Changes in climate and catchment processes over the middle and late Holocene in the boreal region of northeastern Ontario, Canada

contributor:
Cumming, Brian F.
Biology

rights: Attribution-NonCommercial-NoDerivs 3.0 United States

subject:
Paleolimnology
Holocene
boreal forest
climate change
pollen
diatoms
sedimentary pigments
eutrophication
light attenuation
XRF
dissolved organic carbon
terrestrial input
elemental geochemistry
generalized additive models
lake

abstract:
The climate of North America has varied substantially over the Holocene. Holocene Thermal Maximum (HTM) warmth occurred earlier in the west with associated aridity, compared to the east which was humid. Specific regions of North America, however, are underrepresented in continental reconstructions of Holocene climate including boreal northeastern Ontario (Canada). This thesis examines pollen, pigments, diatoms, and elemental geochemistry from three sediment cores retrieved from two small, headwater, boreal lakes in elevated watersheds to examine changes in climate, lake-production, lake-level, redox status, and terrestrial input over the middle and late Holocene of the region. Analysis of proxies suggest warm and wet climate conditions that were accompanied by high lake-production, low hypolimnetic oxygen concentrations, reducing sediment-water interface conditions, and a high degree of input from the watershed from ~6000–4000 cal yr BP. Lake-level may have been lower during this time as high rates of evapotranspiration likely counteracted high amounts of precipitation. These conditions were reversed past ~4000 cal yr BP due to declines in both temperature and precipitation. Cohesion among proxies within and between lake systems suggest trends are tied to regional changes in climate and that this region experienced a delayed and humid HTM compared to northwest Ontario. Intra-lake discrepancies in pigments and geochemistry, however, suggest basin-specific deposition of inorganic catchment material due to morphometry and sediment focusing. These discrepancies suggest that researchers should exercise caution when interpreting regional signals from single core studies.
This thesis also examines the role of light attenuation in structuring modern diatom assemblages within lakes. Diatoms collected from surface sediments in depth-gradient transects suggest that light attenuation is a strong driver of benthic-planktonic (B:P) assemblage separation compared to other variables (e.g., the thermocline). Comparisons with previously studied boreal lakes suggest that DOC concentration can act as a predictor of B:P boundary depth. As new techniques are attempting to reconstruct DOC concentrations through time, past changes in light regime may soon be included in common paleolimnological interpretations. This thesis warns that ongoing anthropogenic warmth may result in eutrophication and alterations to light regimes within presently clear, oligo- and mesotrophic lakes in boreal northeastern Ontario.

abstract: PhD


title: Direct and indirect effects of host food quality on host life history, host susceptibility to parasitism, and parasitoid life history

contributor:
Nelson, William A.
Lougheed, Stephen C.
Biology

subject:
Tri-trophic Interactions
Consumer life histories
Resource-Host-Parasitoid Interactions
Insect Ecology

abstract: Ecological communities are complex, comprising species and environmental factors that are so entangled in their effects on one another that ecologists and evolutionary biologists will forever be mystified by how they are assembled and function. Against such complexity, we have come to understand that autotrophic resources can have large cascading impacts on higher trophic levels via direct interactions (the effect of one species or environmental factor on another). However, because of indirect interactions (between species or environmental factors that are mediated through direct interactions with other species or factors), the relationships and dynamics we expect in natural communities are often not observed. In this thesis, I investigate how food resources directly impact consumer life histories and how this direct interaction indirectly impacts tertiary consumers in an experimental resource-host-parasitoid community. First, I refine an artificial resource system, and develop a technique to transfer seed beetle (host) eggs laid on natural legume seeds to artificial seeds which set the stage for the two highly replicated experimental life history assays in this thesis. In the first study, I ask whether variation in host life history traits in response to food quality is consistent within and across stages of host development. Using a cross-sectional experimental approach combined with a stage-structured population model to estimate instar specific host vital rates, I show that food quality effects on host vital rates, growth and development are not consistent throughout ontogeny, suggesting host food quality may cascade to impact host susceptibility to parasitism and parasitoid life histories. In the second study, I ask whether host food quality indirectly cascades to impact host susceptibility to parasitism and parasitoid life histories. Using a similar cross-sectional approach, I show host food quality indirectly impacts host susceptibility to parasitism but has little to no effect on parasitoid life histories. Overall, my research shows that, despite large effects on host life histories, host food quality effects are markedly reduced in parasitoids in this system, emphasizing the need to consider specific species life histories when characterizing resource-host-parasitoid community relationships and dynamics, and whether or not resources cascade to impact higher trophic consumers.

abstract: PhD


title: Transposing Resonance: Towards an Embodied Poetics of Music

relation: Canada Graduate Scholarship - Master's (CGS-M)

subject:
poetics
writing
music
musicology
musical experience
listening
embodied listening
language
transposition
writing about music
resonance

abstract: My project seeks to reenergize the capacity of the written word to relay differentially embodied musical experiences. I theorize writing of, and writing for, music as a processual act of transposition, working through the intuited shortfall and transposing resonance into language that both preserves melodic identity and amends through personal narrative. With the approaches of musicology and popular music studies in mind, as well as pursuing other artistic and interpersonal tools within and beyond academia, I argue that this writing practice can expand the emotional lexes of readers/listeners, adding to the multilayered experience of music, leaving embodied indentations and incantations to follow— nothing t(oo)uneful(l) to remain untraced. This preliminary literature review provides an overview of how writers in various fields have approached the topic of musical discourse. These texts equip me with the philosophies, intentions, and language to analyze exemplary writing on music, compiling methods that I will eventually try to replicate and redevelop in my own writing practice.


title: Toll-like receptor mediated responses to adsorbed damage-associated molecular patterns on biomaterial surfaces

contributor:
Fitzpatrick, Lindsay
Woodhouse, Kimberly
Chemical Engineering

subject:
Macrophage
Toll-like receptor
Foreign body reaction
Protein adsorption
Polymeric biomaterials
Damage-associated molecular patterns
Insulin infusion cannulas
Inflammatory response
Immunology

abstract:
The foreign body reaction is a chronic inflammatory response to an implanted biomaterial that ultimately leads to fibrous encapsulation of the implant. It is widely accepted that the host response to implanted biomaterials is largely dependent on the species and conformations of proteins adsorbed onto the material surface, due to the adsorbate’s role in mediating cellular interactions with the implanted material. While the cellular response to adsorbed serum-derived proteins has been studied extensively, the presence of endogenous, matrix- and cell-derived mediators of inflammation within the adsorbed protein layer and their impact on cell-material interactions is not well understood. Damage-associated molecular patterns (DAMPs) are endogenous ligands released by stressed or damaged tissues to stimulate sterile inflammatory responses via Toll-like receptors (TLRs) and other pattern recognition receptors. The work in this thesis explored the contribution of cellular damage molecules in cell lysate and TLR signalling in macrophage responses to a range of non-resorbable polymers, including insulin infusion cannulas.
The in vitro data showed that adsorbed DAMPs on polymeric surfaces, both alone and in the presence of blood proteins, strongly induced NF-B/AP-1 transcription factor activity and pro-inflammatory cytokine secretion in reporter macrophages, compared to serum- and plasma-adsorbed surfaces. Lysate-dependent NF-B/AP-1 activation and cytokine production was strongly attenuated by TLR2 neutralizing antibodies. Work with primary bone marrow-derived macrophages confirmed the similar contribution of TLR2- and MyD88-dependent signalling in pro-inflammatory, anti-inflammatory, and angiogenic cytokine gene expression and production in response to model cannula surfaces with adsorbed DAMPs and plasma. Trends in the results from short term cannula implants in wildtype (WT) and TLR-knockout mice demonstrated that, while WT mice had an increase in inflammation over the 7 days, TLR2-/- and MyD88-/- mice had a decreasing trend. Furthermore, TLR2-/- and MyD88-/- mice had similar inflammatory cell layer thicknesses after 7 days, which were thinner than in WT mice. The results of the work presented here demonstrate that TLR2- and MyD88-dependent signalling are promising targets to modulate the acute inflammatory response, and merit further investigation.

abstract: PhD


title: The Role of Sociability in Political Philosophy

contributor:
Kymlicka, Will
Philosophy

subject:
Political Philosophy
Human Sociability
Political Authority
Anarchism
David Hume
Peter Kropotkin
Thomas Hobbes
Max Stirner
Steven Pinker
Evolutionary Psychology

abstract: This dissertation identifies, and argues in support of, the fundamentally important role that accounts of sociability play in the project of political philosophy. I will show that assumptions about the nature of human sociability implicitly or explicitly underlie all theories of political governance.  When theorists explain why a state is required (or in the case of anarchists, why a state is not required), they inevitably invoke claims about (i) the nature of humans’ pro-social and anti-social traits, (ii) whether the balance of these traits is such that individuals are able to freely and successfully interact without state intervention; and (iii) whether and how the state can help address any imbalances of these traits that would undermine successful social interaction. While this general schema – what I call the “generic account of sociability” - is found in both early modern and contemporary political theories, early modern theorists were much more self-conscious and explicit about the role that sociability plays in their theories, whereas with many contemporary political theorists, this role has become hidden or obscured.  I will argue that these assumptions must be made more explicit, and must be assessed more systematically both for their internal consistency and for their compatibility with contemporary scientific findings about human sociability. There are in fact a number of unresolved tensions and ambiguities within both early modern and contemporary political theories about how exactly assumptions of sociability underpin a justification of the state’s existence. In this dissertation, I try to identify some of these key tensions and ambiguities, and offer some methodological suggestions for how political philosophy can make progress on this fundamentally important issue.

abstract: PhD


title: Unsupervised Multi-Modal Representation Learning using Convolutional Autoencoders for Affective Computing with Wearable Data

contributor:
Etemad, Ali
Hungler, Paul
Electrical and Computer Engineering

subject:
Affective Computing
Machine Learning
Arousal
Electrocardiogram
Electrodermal Activity
Autoencoder
Unsupervised Learning

abstract: With recent developments in smart technologies, there has been a growing focus on the use of artificial intelligence and machine learning for affective computing to further enhance the user experience through emotion recognition. Typically, machine learning models used for affective computing are trained using manually extracted features from biological signals. Such features may not generalize well for large datasets and may be sub-optimal in capturing the information available in the raw input data. One approach to address this issue is to use fully supervised deep learning methods to learn latent representations of the biosignals. However, this method requires human supervision to label the data, which may be unavailable or difficult to obtain. In this work we propose an unsupervised solution for representation learning to reduce the reliance on human supervision. The proposed framework utilizes two stacked convolutional autoencoders to learn latent representations from wearable electrocardiogram (ECG) and electrodermal activity (EDA) signals. These representations are then utilized by a random forest model to classify arousal into high and low classes. This approach reduces human supervision and enables the aggregation of datasets allowing for higher generalizability. To validate this framework, a multi-corpus dataset comprised of 4 separate datasets, namely AMIGOS, ASCERTAIN, CLEAS, and MAHNOB-HCI, is created. The results of our proposed method are compared with a number of other methods including convolutional neural networks, as well as methods that employ manual extraction of hand-crafted features. The methodology used for fusing the two data modalities (ECG and EDA) is also investigated. Lastly, we show that our method outperforms other works that have performed multi-modal arousal detection on the same datasets, achieving new state-of-the-art results for all the datasets used. The results show the wide-spread applicability for stacked convolutional autoencoders to be used with machine learning for affective computing.

abstract: M.A.Sc.


title: Repeats-In-Toxin Adhesion Proteins: What Makes Them Stick?

contributor:
Davies, Peter
Biomedical and Molecular Sciences

subject:
Biochemistry
X-ray Crystallography
RTX Adhesin

abstract:
Bacteria use adhesion proteins (adhesins) to bind substrates on biotic and abiotic surfaces to initiate biofilm formation. These bacterial communities can be detrimental to a host when, for example, they cause teeth plaques, chronic infections, and the contamination of food products. On the other hand, they can also promote plant growth and the degradation of oils, depending on the organism. Characterizing adhesin interactions may present opportunities to inhibit destructive biofilms and reinforce the advantageous ones.

A subgroup of these proteins called Repeats-In-Toxin adhesins are exported by a type 1 secretion system and are retained on the outer membrane of some Gram-negative bacteria. This thesis examined C-terminal ligand-binding domains from three different adhesins: 1) The large adhesion protein from the oil- degrading bacterium Marinobacter hydrocarbonoclasticus, contains a PA14 domain with the ability to bind specific carbohydrates. This 20-kDa domain was tested as a dextran-affinity tag for purification of recombinant proteins on dextran-based size-exclusion resins. The tag bound to Superdex, Sephadex, and Sephacryl, and proved to be superior to nickel-affinity chromatography. 2) A medium adhesion protein from Pseudomonas fluorescens, which contributes to biofilm formation on plant root surfaces, contains a von Willebrand Factor A domain in the C-terminal region that was characterized by X-ray crystallography. While human integrin contains a homologue of this domain to bind extracellular matrix proteins, including collagen, the binding partner for Pseudomonas fluorescens is still unknown. Lastly, 3) the flagellum-regulated hemagglutinin A, which binds to epithelial cells and erythrocytes in the pathogenic lifecycle of Vibrio cholerae, does so through a peptide-binding domain. This protein was produced with its neighboring domain and co-crystallized with nanomolar-affinity pentapeptide ligands. These peptides successfully inhibited attachment of V. cholerae to erythrocytes and could potentially be used for anti-adhesion therapy against cholera.

abstract: M.Sc.


title: A Deep Learning Network for Validation of 3D Point Cloud Surface Registration

contributor:
Greenspan, Michael
Electrical and Computer Engineering

rights: Attribution-NonCommercial 3.0 United States

subject:
Surface Registration
3D Object Recognition
Validation
Shared mlp Network
Point Cloud

abstract: This thesis proposes a novel deep learning architecture called ValidNet to automatically validate the correctness of a 3D surface registration outcome. The performance of many tasks such as object detection mainly depends on the applied registration algorithms, which themselves are susceptible to local minima. Revealing this tendency and verifying the success of registration algorithms is a difficult task. We treat this as a classification problem, and propose a two-class classifier to distinguish clearly between true positive and false positive registration outcomes. Our proposed ValidNet system deploys a shared multilayer perceptron architecture which works on the raw and unordered  point cloud data of scene and model points. This network is able to perform the two fundamental tasks of feature extraction and similarity matching using the powerful capability of a deep neural network. Experiments on a large synthetic dataset show that the proposed method can effectively be used in automatic validation of 3D surface registration.

abstract: M.A.Sc.


title: On Optimal Codes for Additive Noise Channels

contributor:
Wehlau, David
Alajaji, Fady
Mathematics and Statistics

subject:
Communications
Coding Theory

abstract:
One of the fundamental goals of coding theory is to find optimal codes, in terms of achieving the largest probability of correct decoding. Most of the foundational works on optimal codes use three assumptions. First, optimality is defined relative to a code’s rate and minimum Hamming distance, and not its probability of correct decoding. The problem is that the former conditions are not always good indicators for the latter. Second, for practicality only optimal codes with some kind of algebraic structure are considered, the most common being linearity. While linear codes have practical advantages, it is known that often the best codes are not linear. Thirdly, codes are usually proven optimal only for memoryless channels. However, there are many real-life channels which exhibit memory. Attempts to extend these results often make use of interleaving. This technique renders some of these channels with memory equivalent to a memoryless one with respect to the decoder. However, this comes with two disadvantages namely: we fail to exploit the channel’s memory and we add latency to the communication system.
In this thesis, we seek optimal codes which require milder conditions than those aforementioned. Specifically, we describe a class of optimal q-ary block codes over additive noise channels, which are a generalization of a class of optimal codes from Hamada. We prove these codes are optimal using our novel method of analyzing the probability of correct decoding of block codes based on so-called error indexed decoder regions. Our method allows us to prove that these codes must be either a linear code or a coset of one.

abstract: M.Sc.


title: Re-imagining Canada’s Child Welfare Paradigm: A Collective Ethnographic Case Study of Canadian and Finnish Child Welfare Systems

contributor:
Burfoot, Annette
Sociology

subject:
Sociology
Social Policy
Aboriginal Mothering
Risk
Intensive Mothering
Child Welfare
Finland
Situational Vulnerability

abstract: This dissertation analyzes state-family relations in Canada, and collectively alongside Finland, as they relate to mothering and child welfare. In response to calls from the Canadian Federal Ministry of Child and Youth Services (2015) to increase access to preventative services and family support, this research project endeavours to contribute to the conversation of child welfare reform. With the application of a sociological lens, and situated within the disciplinary framework of Sociology of the Family, this research employs a collective ethnographic case study that facilitates an integrated analysis of theory, policy, practice, and lived experiences to explore the entanglement of gender, race, situational vulnerability, intensive mothering, and social constructs of risk. The whole of this dissertation adopts a manuscript-style format. Together, the three manuscripts that compile the body of this research, knit together to produce a meaningful analysis that confirms, as well as offers insight, into the necessity of doing child welfare differently in Canada. The goal to re-imagine Canada’s current child welfare paradigm is explored in this space. The research here argues that the vision, which accompanies calls for greater access to proactive resources as a branch of Canada’s child welfare paradigm, requires a shift in state-family relations. This shift must not only strive to understand past relations involved in the delivery of Canadian child welfare, but situate the current paradigm, and look towards practical reform with insight derived from other nations.  Part of this reform analysis is based on a collective analysis with Finland’s approach to child welfare. Although Finland is not without its own social problems, Finland’s recognition as one of the best countries in the world to be a mother invites global attention in the quest to re-imagine how child welfare can be done differently.

abstract: PhD


title: MACHINE LEARNING ENHANCEMENTS FOR KNOWLEDGE DISCOVERY IN MINERAL EXPLORATION AND IMPROVED MINERAL RESOURCE CLASSIFICATION

contributor:
Ortiz, Julian M
Olivo, Gema R
Mining Engineering

subject: Machine learning in mineral exploration

subject: Machine learning in mineral resource classification

abstract:
Contemporary issues of the mining industry, such as declining grades, increasing depth of deposits, cost per discoveries and demand for the raw materials are driving the mining industry to develop and adopt improved technologies. The main objective is to achieve success in exploring deeper parts of the earth and improve mining and processing technologies. These emerging technologies generate enormous amounts of data, therefore utilizing all the available data efficiently has become one of the biggest challenges for geoscientists and engineers.
Machine learning (ML) algorithms are being deployed to handle the abundance of data in many traditional fields (e.g., computer vision, natural language processing and genetics) due to their fast processing capability. Despite its potential benefits, ML has not been fully adopted by the mineral exploration and resources sector yet. This thesis demonstrates that ML can assist in improving mineral exploration strategies and mining procedures by enhancing the understanding of processes from high dimensional data and by automating operations. An overview of state-of-the-art applications of different ML approaches and their relevance to the mineral exploration and resources sectors is presented by means of two original case studies. Furthermore, a generic workflow for ML application in geoscience is proposed to highlight good practices in their implementation.
The first case study encompasses an example of a multivariate analysis applied to a lithogeochemical dataset from the Vazante-Paracatu District, Brazil, in order to provide insights about processes related to the base metal mineralizing system. The complex relationships between the data and the mineral occurrences are revealed to assist in finding new targets for zinc exploration.
The second case study is an example of ML applied to resource classification, which normally relies on expert assessment of a qualified person to determine if the blocks of a 3D mineral resource model are classified as measured, indicated, or inferred. This study reveals that ML can assist to increase time efficiency of the task and improve consistency by automating the process.
These applications demonstrate the relevance of ML methods in supporting knowledge discovery in geosciences and engineering and automating processes for improved consistency in the results.

abstract: M.A.Sc.


title: Sessile Droplet Microfluidic Platforms for Improvements in Mass Spectrometry Sample Preparation

contributor:
Oleschuk, Richard
Chemistry

subject:
mass spectrometry
microfluidics
droplet

abstract: Sessile droplet microfluidic devices (SDMF) allow for small, uniform liquid volumes to be arrayed, addressed, and manipulated independently. SDMF platforms diverge from typical flow-based lab-on-a-chip (LOC) devices while maintaining their advantages (low sample consumption, high throughput, and easy automation and portability). Previous work by Bachus et al. has shown that SDMF arrays can be made rapidly and reproducibly by applying a hydrophobic coating to a glass surface, then milling surface energy traps (SETs) into the surface using picosecond laser micromachining. Resulting SETs serve as anchor points to hold liquid droplets and can be filled spontaneously by discontinuous dewetting (DDW). By modifying the SET shape, evaporation dynamics of droplets can be controlled so that solute particles inside droplets are confined to a certain location, thus achieving droplet preconcentration with no further steps. The means to preconcentrate sessile droplets on open surfaces serves as an attractive option to improve the sample preparation and detection sensitivity for various mass spectrometry-based analytical techniques. Preliminary results show a significant increase (18-fold) in colourimetric detection sensitivity of cadmium-dye complexed droplets on SETs. SET designs were then modified to improve suitability of the platform for analysis in matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). Microscopy and MALDI imaging mass spectrometry (IMS) were used to assess analyte localization and matrix application methods. MALDI sample spot reduction using evaporative preconcentration was shown to increase detection sensitivities two-fold. Finally, arrays of miniaturized SETs (“microspots”) were explored as an open surface platform for single cell isolation and analysis. Using silica particle suspensions, microspot fabrication was optimized for single particle occupancy and average particles per microspot.

abstract: M.Sc.


title: Fluid-Structure Interaction of Large Viscoelastic Vessels Under Pulsatile Conditions

contributor:
Rival, David E.
Bisleri, Gianluigi
Mechanical and Materials Engineering

subject:
Aorta mechanics
Ultrasound
Constitutive laws
Cylindrical loading
Elastic properties
Viscoelastic behaviour

abstract: The current threshold diameter for aortic aneurysm repair is based on Laplace's law. However, aneurysms below this threshold have undergone dissection, while some larger aneurysms remain stable. An accurate understanding of how the dynamics of the aorta - particularly the fluid-structure interaction - relate to aneurysm progression is fundamental to streamlining clinical decisions. This thesis encompasses an experimental investigation into the response of compliant vessels to pulsatile flow for the purposes of properly characterizing the vessel-wall material properties. The structural deformation of, and flow field within, the compliant vessel were recorded using ultrasound imaging. The ultrasound data were then used to estimate the instantaneous elasticity of the vessel wall through a novel, dynamic model developed from a force analysis of a compliant vessel under two-dimensional (2D) stress. First, the instantaneous elasticity of a purely elastic, synthetic vessel with known properties was extracted using the 2D stress model and compared to Laplace's law. The 2D stress model was found to better predict the trend and magnitude of elasticity than the results from Laplace's law. Second, the instantaneous elasticity and dynamic viscoelastic properties of a porcine ascending aorta were calculated and compared to results from dynamic uniaxial testing. The instantaneous elasticity of the intact aorta matched well with uniaxial results, while the viscoelastic properties differed significantly between the cylindrical and uniaxial stress states.

abstract: M.A.Sc.


title: PROSPECTIVE BINDER SYNTHESIS AND STRUCTURAL STUDIES OF GUANINE QUADRUPLEXES

contributor:
Petitjean, Anne
Chemistry

subject:
Nucleic Acids
Quadruplexes
Carbamate Synthesis
Nuclear Magnetic Resonance Spectroscopy

abstract:
Guanine Quadruplex (G4) architectures have been a hot research topic for decades, claiming
much of their fame due to their demonstrated potential for regulating various diseases, such as cancer,
infections, and neurological disorders, at both the level of DNA and RNA. As a result of their
demonstrated importance and relevance to medicine and future treatment options for patients, the
development of a series of binders that can achieve selective stabilization of these architectures is highly
sought after. The objective of this MSc dissertation is to synthesize a series of binders for future
assessment of their interactions with higher order G4 architectures.
First, synthetic routes for developing carbamate-functionalized naphthyridine derivatives were
considered in accordance with literature procedures to assess how naphthyridine-based molecules would
interact with G4 architectures, more specifically, whether they would disrupt or provide enhanced
stability for G4s. Two methods for introducing carbamates into the binders’ design were considered, and
one determined to be optimal.
Second, a synthetic route for developing a binder for stabilizing the G4 formed in the promoter
region of the Rearranged After Transfection (RET) gene is discussed. A family of platinum-based binders
inspired by previous work in the Petitjean lab is described, and their synthetic route presented.
Lastly, an introduction to the use of Nuclear Magnetic Resonance Spectroscopic methods in the
elucidation of quadruplex structures is described. This study investigates the very first monomolecular
RNA G4 architecture that is formed by the B-Cell Lymphoma/Leukemia 2 (BCL-2) proto-oncogene,
reporting the structural assignment of all guanine nucleobases within this architecture.
The body of work described herein, namely the synthetic methodologies described and the
elucidation of an RNA G4 architecture, lays the foundation for the future development of selective G4
binders. As a result of the regulatory roles of G4s in diseases such as cancer, the binders discussed will
inspire the creation of more effective treatment options for future patients.

abstract: M.Sc.


title: Ruling Islamists’ Approaches to Minorities in Sudan and Turkey

contributor:
Haklai, Oded
Political Studies

subject:
Islamists
Ethnic Minorities
Turkey
Sudan
Kurds
Darfuris
South Sudanese

abstract:
Ruling Islamists’ interactions with ethnic minorities have been largely understudied and undertheorized. This research study examines ruling Islamists’ treatment of minorities, asking two questions. The first question is how do ruling Islamists treat minorities? And the second is what explains their treatments? To the extent that extant literature addresses these questions, it offers cultural-based explanations that stress the role of religious affiliation, suggesting that Islamists are more likely to accommodate co-Muslim ethnic minorities, and exclude, or perhaps repress, non-Muslim others.
This dissertation sets to address its questions through investigating Islamists’ approaches to the animist and Christian South Sudanese and Muslim Darfuri minorities in Sudan, as well as the Muslim Kurdish minority in Turkey. In contrast to what the ideational-centric literature expects, this research study has found that in both Sudan and Turkey Islamists lacked a coherent approach toward minorities. Rather, their strategies changed across time toward the groups examined between accommodative and repressive or vice versa. In addition to the presence of within-group diachronic variations, the case of Sudan also demonstrated across-group co-temporal variations in the treatment of minorities.
Since governing Islamists shifted their approaches toward all minority groups, despite differences in the groups’ religious affiliations, this study refutes the ideational-centric analysis. Instead, this research has found political strategic calculus to have had a considerable influence in shaping Islamists’ policies toward their respective minorities. This strategic calculus was shaped by two factors. The first was the necessity of building domestic alliances, which was largely an outcome of the strategic interactions between actors, including intra-Islamists’ interactions, and the varying formal and informal structures in place. The second factor involved the regional and international dynamics that influenced the minority groups’ participation in domestic alliances through affecting their strategic capacity. While domestic actors’ strategic interactions affected the need for alliance-building, regional and international dynamics affected the configuration of such alliances by influencing the desire of potential minority groups to participate as allies.

abstract: PhD


title: Performance of Geosynthetics for Remediation of Hydrocarbons and Emerging Contaminants

contributor:
Rowe, R. Kerry
Civil Engineering

subject:
geomembrane
geosynthetic clay liner
TCE
PCE
BTEX
vapour intrusion
diffusion
Antarctica
PFOA
PFOS
EVOH

abstract:
Diffusion of volatile organic contaminants through a thin (0.508 mm) seven-layer geomembrane including EVOH was evaluated using laboratory diffusion tests and compared to traditional polyethylene geomembranes. Using the laboratory tests, diffusion (Dg), partitioning (Sgf) and permeation (Pg) coefficients were developed for the EVOH layer and the complete liner. The seven-layer membrane resulted in a decrease in steady-state flux by a factor of 19.2-64.4 compared to 1.5 mm HDPE.
Transport of TCE and PCE through geomembranes, including two geomembranes coextruded with EVOH, was assessed through laboratory testing. Dg, Sgf, and Pg values were developed for the individual materials, and single layer Dg, Sgf, and Pg values were developed for the coextruded geomembranes using the harmonic mean of the Pg values and the weighted average of Sgf values in relation to the layer thicknesses. Vapour intrusion models were used to compare the vapour intrusion of TCE and PCE into a warehouse with a constant source of contaminant. Modelled concentrations were significantly reduced where coextruded geoemembranes are present by more than a factor of 10, compared to single material geomembranes of similar thicknesses.
Laboratory testing of PFOA and PFOS diffusion through four geomembranes at multiple temperatures was examined. Laboratory testing of 0.1 mm LLDPE and LLDPE coextruded with EVOH showed extremely low (<8 μg/L) concentrations of PFOA and PFOS after over 400 days of testing. Elevated temperature testing of 0.75 mm LLDPE and LLDPE coextruded with EVOH showed similarly low receptor concentrations after over 350 days. Estimated permeation coefficients for PFOA and PFOS through LLDPE are less than 5.2x10-15 m2/s.
Laboratory testing of exhumed GCLs from an Antarctic site examined performance properties of GCLs post-exposure. Small changes in hydraulic conductivity and swell index were observed, however these values were not significantly different than virgin values. A field scale hydration test plot was constructed to assess the impact of subgrade on GCL performance. GCLs overlying sieved soils (<50 mm) had more consistent hydration throughout the field season and smaller indentations, indicating better long-term performance. Inclusion of a geotextile in the subgrade resulted in lower hydration due to the geotextile acting as a capillary break

abstract: PhD


title: The Compositional associations of time spent in sleep, sedentary behaviour and physical activity with all-cause mortality

contributor:
Janssen, Ian
Public Health Sciences

subject:
Compositional Data Analysis
sleep
sedentary behaviour
physical activity
24-hour movement behaviours
public health

abstract:
INTRODUCTION: Daily time spent in sleep, sedentary behaviour (SED), light intensity physical activity (LIPA), and moderate-to-vigorous intensity physical activity (MVPA) are compositional, co-dependent variables. The objective of this study was to use compositional data analysis (CoDA) to examine the relationship between the movement behaviour composition (daily time spent in sleep, SED, LIPA, and MVPA) and all-cause mortality risk.
METHODS: 2,838 adult participants from the 2005-2006 cycle of the U.S. National Health and Nutrition Examination Survey were studied. Daily time spent in SED, LIPA, and MVPA were objectively determined by accelerometer. Time spent sleeping per night was self-reported. Survey data were linked with mortality data through to the end of December 2015. CoDA was used to investigate relationships between the movement behaviour composition and mortality.
RESULTS: The movement behaviour composition was significantly associated with mortality risk. Time spent in MVPA relative to other movement behaviours was negatively associated with mortality risk (HR=.74; 95% CI [.67, .83]) while relative time spent in SED was positively associated with mortality risk (HR=1.75; 95% CI [1.10, 2.79]). Time displacement estimates revealed that the greatest changes in mortality risk occurred when time spent in MVPA was decreased and replaced with sleep, SED, LIPA, or a combination of these behaviours (HRs of 1.76 to 1.80 for 15 minute/day displacements).
CONCLUSION: The daily movement behaviour composition was related to survival. Replacing MVPA or SED with any other movement behaviour was associated with an increase and decrease in mortality risk, respectively.

abstract: M.Sc.


title: Topology Optimization and Additive Manufacturing-based Parts Consolidation of an Aircraft Avionics Pedestal

contributor:
Kim, Il Yong
Mechanical and Materials Engineering

subject:
Design for Additive Manufacturing
Topology Optimization
Parts Consolidation
Aerospace Design
Lattice Optimization

abstract: An avionics pedestal is the structure located in the center of the cockpit that houses the flight controls and critical electronics for the operation of the aircraft. This thesis presents a parts consolidation design approach, incorporating topology optimization-based design for additive manufacturing, applied to the center avionics pedestal for a Bombardier business jet with the objective of reducing the component count, joint count, assembly time and total unit cost. The current pedestal design is limited by the use of traditional manufacturing methods and materials, making it a great candidate for this redesign process. The redesign process began by simplifying the model of the original pedestal to create a design space that accounted for assembly and maintenance constraints, as well as the spacing required for the electronics and controls. Topology optimization was performed to aid the parts consolidation and additive-manufacturing based re-design process by providing the most efficient material layout to generate initial designs, based on the pilot effort limit loads and emergency loads applied to the structure. Next, the preliminary designs were carried through a design refinement stage where additional design optimizations of free-size and lattice optimization were performed to achieve mass reductions. These structures were then verified using a linear-static stress analysis against the certification loads. The final redesigned pedestal consisted of an outer sheet metal enclosure, and two polymer additively-manufactured components comprising the interior of the pedestal to support the avionics themselves. The two additively-manufactured parts replaced a large number of previously machined metallic components, resulting in a 72% reduction in part count and a 44% reduction in joint count. The reduction in part count and joint count resulted in a cost reduction for the redesigned pedestal, meeting the main objectives of the project and highlighting the benefits of using this approach for future aircraft design.

abstract: M.A.Sc.


title: Neural Correlates of Sexual Response: An ERP Investigation of Responses to De-Contextualized Sexual Cues

contributor:
Chivers, Meredith L.
Psychology

subject:
sexual response
neural response
event-related potential
electroencephalography
gender

abstract: Sexual response relies on the perceptual and cognitive processing of sexual stimuli. With its high temporal resolution, the event-related potential (ERP) technique offers an ideal tool for studying early processes involved in sexual response. Previous research on ERP responses to sexual stimuli has used visually complex stimuli (e.g., couples, full nude bodies). Interpretations are limited because ERPs heightened to these stimuli include processing of both sexual and nonsexual cues that differ from controls. In this dissertation, I present ERP data from three studies aimed at elucidating neural responses involved in processing sexual cues. In Study 1, opposite-gender attracted undergraduate women (N = 40) viewed images of sexual and nonsexual body parts varying in activity state (flaccid or erect penises; relaxed arms or flexed biceps). In Study 2, opposite-gender attracted undergraduate women (n = 27) and men (n = 28) viewed images of sexually-preferred and non-preferred body parts varying in readiness for sexual activity (flaccid or erect penises; pubic triangles or exposed vulvas). Study 3 replicated Study 2 methods in a community sample (n = 25 women, n = 22 men). All studies used high- density 128-channel EEG nets and modern whole-head analysis. In Study 1, undergraduate women had widespread centro-parieto-occipital activation to sexual cues beginning as early as 100ms. Effects were replicated in Study 2 and extended to men, with limited differences based on sexual relevance/reward value of stimuli. Results replicated in a community sample (Study 3), where some ERPs in men’s early and later processing were sensitive to sexually-rewarding cues. Across studies, I link a novel ERP with sexual processing that may involve inferring the intentions or emotions of others. Results offer new insights into sexual processing on the neural level while revealing multiple areas for future investigation into early stages of sexual response.

abstract: PhD


title: Exploring First-Year University Students’ Barriers and Facilitators to Meeting the Recommendations of the Canadian 24-Hour Movement Guidelines for Adult

contributor:
Tomasone, Jennifer
Kinesiology and Health Studies

subject: 24-Hour Movement Guidelines

subject: Physical Activity

subject: Sedentary Behaviour

subject: Sleep

subject: University Students

subject: Barriers

subject: Facilitators

subject: Knowledge Translation

abstract: The majority of university students do not meet the recommended amounts of physical activity (PA), sedentary behaviour (SB) and sleep, which can impact academic success. The forthcoming Canadian 24-Hour Movement Guidelines for Adults (24HMG) are a tool created using a Knowledge Translation (KT) approach, which will provide recommendations for optimal levels of PA, SB, and sleep. In order to address the gap of university students falling short of meeting 24HMG recommendations, the development of an implementation intervention is needed. To inform intervention development, understanding the barriers and facilitators university students face to meeting the recommendations of the 24HMG are necessary. The Consolidated Framework for Implementation Research (CFIR) can be used to assess barriers and facilitators to intervention implementation across five different levels. The purpose of this study is to examine the multilevel factors that allow and/or restrict first-year university students to meet the PA, SB, and sleep recommendations featured in the 24HMG. This study took place at Queen’s University (QU) and the University of British Columbia (UBC). Focus groups consisting of first-year students were conducted at QU and UBC. Inductive thematic analysis identified three themes and 13 subthemes, which were then deductively mapped onto the CFIR domains. The challenges faced by students directly relate to the individual and the value placed on meeting 24HMG recommendations (i.e., characteristics of individuals involved), as well as indirectly through the social and physical environments (i.e., both at the inner setting and outer setting). When developing an intervention to improve students’ movement behaviours on university campuses, the majority of components should remain consistent across campuses, and some components should be tailored specific to the institution. Findings provide a foundation that will contribute to the development of an optimal and evidence-based implementation intervention aimed to optimize movement behaviours among first- year university students.

abstract: M.Sc.


title: BDSM and Women’s Gendered Embodiment: Other-Than-Sex Pleasure, Pain, and Power

contributor:
Dickey Young, Pam
Cultural Studies

subject:
sexuality studies
BDSM
gender
power
pain
pleasure
consent

abstract: Bondage/Discipline/Dominance/submission/Sadism/Masochism (BDSM) is most frequently conceptualized as only non-normative, ‘kinky’ sex. In this dissertation, I combine feminist ethnographic accounts of women’s experiences as BDSM practitioners alongside theoretical frameworks of gendered embodiment to propose a reading of some BDSM practices as other-than-sex. Rather than narrowing the definition of sex, I instead take up Foucault’s expression of the possibilities of bodies and pleasures to explore how alternative relationality is formed between practitioners with some types of BDSM play with pain and power. In doing so, there is an expanded potential for women’s queer pleasure and a real possibility of disrupting patriarchal social structure with practitioners’ altered being-in-the-world. This analysis is centred on accounts from eighteen women participants in Toronto and Ottawa, Ontario, Canada, who were active BDSM practitioners. Participants in this project challenged traditional understandings of pain and masochism to produce new understandings of both. They accounted for safety and risk considerations in practices that help formulate a more robust consideration of the complications of consent in other-than-sex practices than is typically allowed for in either mainstream or BDSM-specific frameworks of consent. Lastly, they expressed conceptions of the strategic eroticization of power that accounted for it in play without eliminating the social power that some bodies exercise more flexibly than others. The alternative relationality that is fostered by other-than-sex BDSM practices is powerfully intimate and based on the radical vulnerability and bodily access between practitioners.

abstract: PhD


title: Feature Engineering and End-to-End Deep Learning in Tool Wear Monitoring

contributor:
Mechefske, Chris
Mechanical and Materials Engineering

rights: Attribution-ShareAlike 3.0 United States

subject:
machine learning
deep learning
machinery health monitoring
variational autoencoder
anomaly detection
tool wear
tool condition monitoring
self-supervised learning
manufacturing
feature engineering

abstract:
Machinery health monitoring is an important tool for improving the productivity of today's manufacturers. Two data-driven techniques are prominent in machinery health monitoring: feature engineering and end-to-end deep learning. The research presented here explores these two data-driven techniques in the context of tool wear monitoring during metal machining. Feature engineering was used as a practical approach to predict when CNC machine tools were worn. A robust data-pipeline was developed, and multiple features and models were tested. The best model achieved a precision-recall area-under-curve (PR-AUC) of 0.349, an acceptable result for the imbalanced data set.

For the first known time in tool wear monitoring, and as a demonstration of end-to-end deep learning, self-supervised learning with a disentangled-variational-autoencoder was used. An anomaly detection technique was employed to make predictions in both the input and latent spaces. The method achieved a top PR-AUC score of 0.45 on a common milling data set. However, the approach generalized poorly across the combination of parts on the industrial CNC data set, but a top score of 0.41 was achieved for certain parts. Further data collection will enhance the results for all approaches. Overall, the work highlights the abundance of opportunities at the intersection between machine learning and machinery health monitoring.

abstract: M.A.Sc.


title: Essays on US Business Dynamics

contributor:
Head, Allen
Cozzi, Marco
Lloyd-Ellis, Huw
Economics

subject:
Economics
Innovation
Business Dynamism
The Firm Life Cycle
Firm Dynamics

abstract:
This dissertation investigates the life cycle dynamics of US firms.  In Chapter 2, I summarize a set of recent trends which I refer to as the ``Decline in US Business Dynamism".  I then build and calibrate a model of firm dynamics which includes each of these measures of business dynamism as endogenous outcomes.  I use this model to examine several potential causes for the trends in question.  In particular, I examine demographic changes, increases in firm market power and changes in fixed, entry and adjustment costs.  I argue that none of the proposed explanations can account for the entire set of facts in on their own.

Chapter 3 of the dissertation introduces a dataset of publicly listed American firms.  I use these data to explore relationships between firm age,  firm growth, R&D spending and patenting.  I find that, conditional on firm size, mature firms conduct less R&D and take out more patents.  However, the patents that mature firms take out are less valuable where the value of a patent is measured both by citations and changes in the market value of the firm.  I then introduce a simple model of firm dynamics and R&D spending to frame the results

Lastly, in Chapter 4 I use a production function estimation approach to analyze the relationship between productivity, firm age and \rd intensity.  These estimates can be used in a wide variety of quantitative applications.  This is because the empirical method that I develop relies on a minimal set of assumptions.  I find that revenue productivity, is positively related to firm size and age.  I also find evidence of a non-linear relationship between R&D intensity and productivity.  The marginal effect of R&D intensity on productivity is higher for more productive firms.  Another emphasis of this chapter is on the uncertainty of the R&D process.  I find that realizations of the volatility of future productivity are positively related to \rd intensity and negatively related to firm age since listing.

abstract: PhD


title: Miniaturized GNSS Antenna Feeding Networks Using Multi-Layer LTCC Technology

contributor:
Freundorfer, Alois
Antar, Yahia
Electrical and Computer Engineering

subject:
GNSS
LTCC
Antenna
Feeding Network
180 Degree Coupler
90 Degree Coupler
Dual-Band Power Splitter

abstract:
Circularly Polarized (CP) antennas are crucial elements in wireless communications, and for geospatial applications such as Global Navigational Satellite Systems (GNSS), their Right-Hand Circular Polarization (RHCP) is an essential property. External feeding networks are responsible for the CP of many antennas, whose function is to excite two orthogonal modes (specific to that antenna) in quadrature phase – but the method at which this is achieved ultimately depends on the type of antenna. Two examples of specific feeding networks are: a) 4-port antennas (i.e. Dielectric Resonator Antennas (DRAs) and Printed Quadrifilar Helical Antennas (PQHAs)) that require an incremental 90° phase delay fed to each port, and b) intrinsically Linearly Polarized (LP) antennas arrays that are fed in relative quadrature phase to their single ports (i.e. 2x2 array of sequentially rotated microstrip patch antennas).
This thesis explores the use of Low Temperature Co-fired Ceramics (LTCC) to highly miniaturize the aforementioned antenna feeding networks into System-on-Package (SoP) solutions with Surface-Mount Technology (SMT) and full 3-D shield features for GNSS frequencies. LTCC technology offers the advantages of reimagining common lumped-element circuits based on passive Surface-Mount Devices (SMDs) as extremely compact multi-layer structures.
Quadrature phase and signal division respective to each feeding network is realized as the combination of various multi-layer lumped-element power splitters and 90°/180° hybrid couplers. In addition, stand-alone chips or dies of each circuit are presented, complementing this thesis as commercially viable products suitable for wideband or dual-band applications over the GNSS spectrum. All circuits were fabricated using 14-layers of FerroA6M LTCC substrate with an 𝜀𝑟= 5.7, tan𝛿=0.001, (from 1-2GHz) and a homogenous layer thickness of 90μm.
Simulations were conducted with ANSYS’ High Frequency Structure Simulator (HFSS®) and Keysight’s Advanced Design System (ADS®) which are in good agreement with measurements.

abstract: M.A.Sc.


title: Energy Recovery from High Salinity Biomass

contributor:
Zeman, Frank
Chemical Engineering

subject:
Phragmite Australis
Biofuel
CKD landfill
biomass
biomass pretreatment

abstract: Phytoremediation is a biological remediation technique where plants take contaminants from the soil into their biological structure. This technique removes pollutants from the ground leaving the grown biomass requiring disposal or additional treatment. Ideally, the biomass is converted to a valuable product. The aim of this study is to recover a solid biomass fuel from plants used for phytoremediation on high salinity soils. This will entail the application of pretreatments on Phragmites Australis, the plant type used, in order to render it suitable for combustion in a cement kiln. Presently, the combustion of the biomass is considered as a sustainable pathway to low carbon fuels in cement manufacturing industry. The investigation characterized Phragmites Australis by energy content (16.29 MJ/kg raw) and salt content (3.81%) using conductivity measurements. In order to lower the salt content, a series of washing experiments were performed followed by analytical testing to determine the suitability of the fuel produced. Further analysis consists of thermal analysis by TGA and calorimetry as well as conductivity measurements Best results observed were 88% chloride removal and 56% ash content decrease. Subsequent dewatering steps were performed to reach a 15% moisture content in final product. The results were used to a preliminary process design for the treatment of biomass produced via phytoremediation of high salinity soils.

abstract: M.A.Sc.


title: SYSTEMATIC STUDY OF MAGNESIUM THIOSULFATE GOLD LEACHING PROCESS

contributor:
Ghahreman, Ahmad
Mining Engineering

subject:
Thiosulfate
Leaching
gold
hydrometallurgy
cyanidation
magnesium
Design of experiments
Response surface methodology

abstract:
Thiosulfate gold leaching is an attractive alternative gold leaching method, especially when it comes to preg-robbing gold ores. The Goldstrike operation of Barrick Gold Corp, Nevada, USA is currently the only calcium-thiosulphate (Ca-TS) leaching operation in the world to leach pregrobbing gold ores. However, recovery with this thiosulfate leaching process is lower than expected. A new thiosulfate technology has been identified for the recovery of various gold ores. Ammonium thiosulfate has been used as the lixiviant along with magnesium hydroxide in the presence of copper as an oxidizing agent. The potential for substantial reduction in thiosulfate consumption while achieving high gold recovery, gives it a cutting-edge advantage over Ca-TS and other thiosulfate gold leaching processes mentioned in the literature. The aim of the study is to evaluate the effect of selected process parameters on gold extraction from the magnesium thiosulfate gold leaching process. These parameters included pH, temperature, concentration of lixiviant (S2O32-), oxidizing agents (Cu), magnesium as magnesium hydroxide as well as air (oxygen source). When pH is increased from 9.00 to the optimum 9.80 using calcium hydroxide, gold recovery drastically improves from 28.4% to 54.3%, showing significantly beneficial impact of pH on MgTS process. Further increasing the copper concentration from 1 mM to 2 mM at constant pH 10 spiked the final recovery (24 h) to be 74.4%, due to increase in the availability of the primary oxidant of copper(II)tetraamine complex while making up for any precipitated copper in the presence of Ca(OH)2.
Further, response surface methodology has been deployed to the critical factors to statistically model, analysis, and optimize the Mg-TS system.  Maximum gold recovery obtained under the range of conditions studied in DOE study gave 74.7% recovery. Given the optimization guidelines, optimal conditions were determined as: thiosulfate concentration of 0.14 M, cupric concentration of 2.00 mM, magnesium of 0.04 g/g and pH 11.00 giving 70.4% gold recovery. Under these conditions, the percentage of gold leaching was slightly compromised (about 4%) in an effort to reduce thiosulfate concentration from 0.19 M to 0.14 M, which amounts to a substantial reduction in reagent cost in practical application of the process.

abstract: M.A.Sc.


title: Predicting the Last Mile: Route-Free Prediction of Parcel Delivery Time with Deep Learning for Smart-City Applications

contributor:
Etemad, Ali
Electrical and Computer Engineering

subject:
last-mile
parcel delivery
origin-destination
predictive modeling
deep learning

abstract: The massive acquisition of parcel data motivates postal operators to foster the development of predictive systems for better customer service. Predicting delivery after the parcels are sent out of the final depot, referred to as \textit{last-mile} prediction, deals with complicating factors such as traffic, drivers' behaviors, and weather conditions. Our work provides an end-to-end neural pipeline that leverages parcel and weather data to accurately predict delivery durations. We present our solution under the IoT paradigm and discuss its feasibility on a cloud-based architecture as a smart city application. We utilize a route-free origin-destination (OD) formulation, only relying on the delivery start and end points. We use a large-scale real-world dataset provided by Canada Post, containing last-mile information of parcels delivered in the Greater Toronto Area in the first half of 2017. We investigate different types of convolutional neural networks and demonstrate how our models outperform several baselines, from classical machine learning models to referenced solutions. Specifically, we show that a ResNet network with 8 residual blocks displays the best performance-complexity trade-off. We provide a thorough error analysis and visualize the features learned to better understand the model behavior, with remarks on data predictability. Our system has the potential to improve the user experience by better modeling their anticipation and to aid last-mile postal logistics as a whole.

abstract: M.Sc.


title: EXPLORING INORGANIC MATERIALS: FROM MOLECULAR SOLAR THERMAL (MOST) ENERGY SYSTEMS TO SOLID-STATE SEMICONDUCTORS

contributor:
Wang, Peng
Wang, Suning
Chemistry

subject: Energy semiconductors ICPMS impurities

abstract:
The rapid growth in the field of N,C-chelate organoborate photochemistry over the past ten years has inspired for research in energy storage. N, C- chelate photochromic organoborates were investigated as potential molecular solar thermal (MOST) energy conversion systems. Nine photochromic boron compounds were selected as the target compounds and converted to their respective photoisomers (“dark” isomers). The catalytic conversion of these high energy photoisomers back to the low energy starting materials using electron acceptors/oxidants was investigated. Trityl tetrakis(pentafluorophenyl)borate was successful at converting the respective “dark” isomers of ppyB(Mes)(3,5-bistrifluorophenyl), (2-ph-py)BMes2 and (5-BMes2-2-ph-py)BMes2 to their respective parent isomers. PpyB(Mes)(3,5-bistrifluorophenyl) was fully recovered when using tris(pentafluorophenyl)borane. Catalytic amounts of trityl fully recovered (2-ph-py)BMes2 in C6D6 but 5 mol% trityl was not enough to recover (5-BMes2-2-ph-py)BMes2. The stability of this photoisomer and the relatively low cost of CD2Cl2 favors this system for energy harvesting.

           Room temperature semiconductor detectors are an important class of gamma-ray sensors because they can generate high-resolution spectra at ambient operating temperatures. This work focuses on the development of high performance, low cost γ-ray detector material, CsPbBr3 at room temperature. Polycrystalline CsPbBr3 was produced (97% yield) from Cs2CO3 and Pb(NO3)2 via solution chemistry routes and its powder X-ray Diffraction (XRD) patterns indicated that they were of the room temperature orthorhombic phase. Despite, the lack of a reference material for CsPbBr3, we establish a method validation of inductively coupled plasma mass spectrometry (ICP-MS) for impurity detection and quantification. The validation includes the performance parameters linearity, range, repeatability (single laboratory precision), instrument limit of detection, limit of quantification. Apart from Cr and Se, a linear increase of detected concentration was observed amongst these elements only. Using method of standard addition, only Tl, In and Sb recovered concentrations comparable to their original values. The segregation of impurities was investigated in three sections cut from an ingot purified by zone refining. The total impurity levels of the zone-refined samples range from 15.7 ± 1.3 to 54.6 ± 1.2 μg/g and depends on the position of the samples within the ingot. ICP-MS also proved that zone refining is effective in producing detector materials.

abstract: M.Sc.