VictorJuiz/thesis huggingface dataset:
Exploring Extended Producer Responsibility: Waste Tyres as a Resource for Job Creation in South Africa?

Extended producer responsibility (EPR) has emerged globally as a means to shift the increasing costs of waste management of end-of-life products onto the producer. This research focused on an EPR scheme for waste tyres that was legislated by the South African government in 2012. While sharing many similarities with other EPR schemes, the South African program was unique in its focus on creating employment. More specifically, in response to the injustices of South Africa’s apartheid there was a focus on the upliftment of previously disadvantaged individuals. Based on semi-structured interviews with actors from various roles in the waste tyre system, this research investigated how the EPR affected employment and whether EPR can be used to create jobs. The EPR scheme for waste tyres in South Africa was found to have increased employment, however, potential challenges with using EPR as a tool for job creation were identified.

Keywords: Employment
Extended Producer Responsibility (EPR)
Integration of Informal Sector
South Africa
Waste Management
Waste Management Policy
Advisor: Maclaren, Virginia
Kepe, Thembela
Vacant Land to Park Transformations as a Catalyst for Neighbourhood Change and Gentrification in Toronto, Ontario

Given the lack of vacant land in the City of Toronto, the redevelopment of available land tends to be highly contested. Stakeholders may advocate for the land to be developed as a park in order to increase social, economic and environmental services provided to residents, both at the neighbourhood scale and city-wide. However, concerns have emerged related to “green gentrification,” which is the exclusion or displacement of vulnerable populations through the creation of green amenities in marginalized neighbourhoods. Using a case study approach to three vacant land to park transformations, this thesis examines how neighbourhood change and gentrification are perceived by actors engaged in the park development process. Using historical analysis, stakeholder interviews, resident surveys and quantitative data analysis, this thesis reveals how the potential for park developments to accelerate gentrification is complex and highly politicized, and perceived more strongly on the ground than it is reflected in changes in quantitative data.

Keywords: brownfields
community engagement
gentrification
neighbourhood change
parks
vacant land
Advisor: Conway, Tenley
Corrosion of Electrodeposited Nanocrystalline Nickel-Iron (Ni-Fe) Alloys in Neutral and Alkaline Sulphate Environments

Electrochemical behaviour of electrodeposited nanocrystalline nickel (Ni) and nickel-iron (Ni-Fe) alloys was assessed in comparison to their conventional polycrystalline counterparts. Alloys of similar composition (Ni, 85Ni-15Fe, 80Ni-20Fe, and 45Ni-55Fe), were investigated to better understand the relationship between grain refinement and alloying on corrosion behaviour. Potentiodynamic polarization tests were conducted in neutral (pH 7) and alkaline (pH 10) sulphate environments. Compared to their polycrystalline counterparts, significant increases in critical current density (icrit), passivation potential (Epass), and passive current densities (ipass) were observed for the nanocrystalline materials in neutral solution. These differences in corrosion behaviour were attributed to the effect of sulphur as a result of a necessary additive in the electrodeposition process more so than the effect of grain refinement. In alkaline medium, no significant effect of grain refinement on the corrosion behaviour was observed. This was attributed to the high OH- concentration, favouring passive film formation.

Keywords: Corrosion
Electrochemistry
Electrodeposition
Nanomaterials
Nickel
Nickel-Iron Alloys
Advisor: Erb, Uwe
Organic Photovoltaics Based on Solution Cast Polymers and Boron Subphthalocyanines – Hybrid Device Architectures Enabling Novel Material Combinations

Solution-cast films of crystalline electron donating poly(3,3”’-didodecylquaterthiophene) (PQT-12) were studied in pseudo-planar heterojunction (PPHJ) organic photovoltaic devices (OPVs) paired with boron subphthalocyanine (BsubPc) as the electron acceptor layer, and the effects of crystallinity domain size and layer thickness were investigated. Annealed, 10-20 nm films of intermediate-sized crystals were 40% more efficient than un-annealed PQT-12 layers and had comparable efficiency to their fullerene-based BHJ counterparts, demonstrating the ability of polymer|BsubPc PPHJ OPVs to accommodate highly crystalline polymers with a tendency to phase segregate and create devices with favorable electrical properties. These polymer|BsubPc PPHJs were further studied with the new amorphous copolymer electron donating material PBTZT-stat-BDTT-8. While optimized PPHJ devices of PBTZT-stat-BDTT-8|BsubPc had substantially lower efficiency than PBTZT-stat-BDTT-8|fullerene BHJs (which were free of morphological problems), they demonstrated comparable performance to their BHJ equivalents due to ideal morphology, presenting a pathway forward for OPV design of otherwise phase segregating polymer|BsubPc pairings.

Keywords: Clean Energy
Organic Photovoltaics
Phthalocyanine
Solar Cells
Advisor: Bender, Timothy P
Investigating Pattern Separation in the Medial Temporal Lobe through the Parametric Manipulation of Item Similarity

Pattern separation is the essential ability to create separate memory representations for overlapping events. This process is accomplished by magnifying the dissimilarity between memories. Computational models posit that the degree to which memories become separated varies as a function of the similarity between them. However, there is little human evidence to support this claim. Using fMRI, we recorded from participants as they performed an explicit memory task in which we manipulated the similarity between study and test items. Our analysis revealed that manipulating similarity did not reliably influence the degree to which memories were separated. We instead found that pattern separation was related to how confident participants were when making decisions related to memory. The implications of this finding, however, remain unclear with future studies needed to interpret them. These results suggest that trial-wise confidence ratings might be a truer measure of mnemonic “similarity” than our group-average similarity measures.

Keywords: fMRI
Medial Temporal Lobe
Pattern separation
Similarity
Advisor: Buchsbaum, Bradley
Application of the Indicator Amino Acid Oxidation Technique to Determine the Protein Quality of Indian Wheat by Studying the Metabolic Availability of Lysine in Healthy Young Adult Men

The protein quality (PQ) of wheat, limiting in Lysine (Lys), is understudied in humans. Wheat and pulse mixed diet (MD) improves PQ but data on combination ratio (CR) is lacking. We aimed to 1)determine the PQ of wheat (bread) by assessing the metabolic availability (MA) of Lys and 2)determine the effect of bread and lentil stew as a MD on PQ by using the indicator amino acid oxidation method repeated measures design in 5 healthy adult males. Based on the slope-ratio principles, L-[1-13C] phenylalanine oxidation (Pheox) to 13CO2 in response to graded Lys intakes fed as crystalline amino acid (reference protein), wheat (test protein), and wheat complemented with lentil (MD) provided the MA and MD effectiveness. Despite being of limiting concentration, the MA of Lys in yeast-leavened bread is 90%. Complementation with lentils reduced Pheox i.e. augmented MD Lys content. We recommend a CR of 2:1 bread to lentil protein.

Keywords: Amino Acid
Bioavailability
Lysine
Protein
Protein Quality
Wheat
Advisor: Courtney-Martin, Glenda
Site Logistics Planning for High Rise Building Construction on Congested Downtown Sites

Construction planning for tall buildings becomes more complex with small land parcels in urban cores, fast-paced schedules and a growing number of domains involved in decision-making. This research consists of evaluating the literature regarding construction planning techniques, decision-making models, constraints in the current construction industry and holding interviews with domain experts to summarize their implicit knowledge regarding construction site logistics planning. It was found that there is no existing tool that adequately optimizes a construction site plan as all research is carried out in isolation, only optimizing a certain piece of equipment or operation. In this research, a multi-domain decision-making tool was developed to assist project planners in site planning on complex construction projects so multiple domain decisions and impacts are simultaneously realized, and a framework for construction site planning that can be applied to the industry was introduced.

Keywords: congested buildings
construction
construction site
decision-making
logistics
Project management
Advisor: McCabe, Brenda
Modular Hip Design Failure: A Forensic Investigation of the Incidence of Liner Dissociation in the Pinnacle-Marathon Acetabular System

The DePuy Pinnacle hip replacement, with Marathon crosslinked ultra-high molecular weight polyethylene liner, was identified as a design with a higher risk of dissociation. The purpose of this study was to identify key features of dissociation failures and analyze those features for evidence of failure mechanisms. A study of 68 dissociation cases revealed such features to be: migration of the liner out of the acetabular shell, deformation of the liner rim, shearing of the locking tabs, and burnishing of the femoral head and acetabular shell. Cases of extreme deformation exhibited fracture through the rim of the liner. Scanning electron microscopy of several liners revealed evidence of fatigue. The failure mechanisms are likely fatigue wear, coupled with impingement – occurring concurrently or consequentially. The key factors which contributed to these mechanisms are component positioning and insufficiencies in the liner locking mechanisms.

Keywords: Dissociation
Failure Analysis
Forensic Investigation
Hip Arthroplasty
Ultra-High Molecular Weight PE
Advisor: Perovic, Doug D
The Development of Learning Across Levels of Abstraction

When we learn about the world around us, we not only process what makes items unique, we also notice consistencies across items. However, it is unknown how learning at these two levels of abstraction interact. Might there be a trade-off in learning? Moreover, given children’s different cognitive abilities, do they experience a similar trade-off? Finally, are irrelevant features still processed, just in a more superficial manner? We explored these questions using a categorization task followed by a surprise recognition test in adults and children. Results suggest that adults do show a trade-off in learning. However, children’s memory scores were too low to make any definitive conclusions. Lastly, both adults and children noticed consistencies in the irrelevant features, and this knowledge also traded-off with category learning in adults and moderately in children. These data point to a fundamental cognitive process in which learning comes at a cost, at least in adults.

Keywords: Abstraction
Category learning
Development
Gist
Memory
Advisor: Finn, Amy S
Effects of Aging on Concrete Containment Structures: An Investigation of Shrinkage and Leakage

While historically used for infrastructure such as buildings, bridges, dams, and roadways, concrete is also a vital component for the storage of energy – especially sources of renewable energy such as natural gas or nuclear. For these applications, the leak-tightness of concrete walls is important and is linked with effects of aging. Most research investigating the leak tightness of concrete structures is outdated and was performed without aging in mind. Additionally, while a large set of experiments have researched the effects of relative humidity on aging, very few have dealt with humidity levels below 40%. This thesis investigates the effects of very dry climates on the shrinkage of concrete and develops an experimental program for analyzing leakage of air through cracks in concrete walls that may develop due to aging processes.

Keywords: Concrete
Leakage
Shrinkage
Advisor: Bentz, Evan C
Kwon, Oh-Sung
Effect of Pegylated Interferon Add-On Therapy to Achieve Disease Remission in Patients with Chronic Hepatitis B

Despite effective vaccination, chronic hepatitis B (CHB) poses a substantial hazard to public health with limited options for finite treatment. A pooled analysis was performed to investigate whether 24-48 weeks of peg-interferon (PEG-IFN) addition could increase response 48 weeks after end-of-therapy compared to continued nucleos(t)ide analogue (NUC)-monotherapy in 234 patients from two investigator-initiated trials. PEG-IFN addition hypothetically increases off-treatment response, particularly after prolonged NUC pre-treatment due to partial immune restoration. Response was observed in 38/118 (33%) patients assigned PEG-IFN addition and 23/116 (20%) assigned NUC-monotherapy (p=0.03). The duration of NUC-monotherapy was associated with HBsAg and HBV DNA, but not directly with response. Re-treating initial non-responders with PEG-IFN add-on did not improve response. PEG-IFN naïve patients with low HBsAg and HBV-DNA levels at randomization achieved the highest response to addition therapy compared with NUC-monotherapy (70% vs. 34%; p=0.01), identifying these as the best candidates for PEG-IFN add-on therapy in clinical practice.

Keywords: Therapy
Viral hepatitis
Advisor: Janssen, Harry L
Milk volume, milk fat and childhood fracture

Background: Although cows' milk is believed to be an important dietary component for supporting bone health, limited research has addressed whether cows' milk consumption in childhood can reduce bone fracture risk. Methods: This was a prospective cohort study of healthy urban children aged 1-10 years. Modified Poisson regression was used to test the association between milk volume and milk fat consumed between 1 and 3 years of age and risk of fracture between 3 and 10 years of age. Results: Among the 2466 children, 153 sustained at least one bone fracture. Participants drank on average 1.9 cups of cows' milk daily (2.5% average milk fat). Neither milk volume or milk fat consumed in early childhood were associated with fracture risk in later childhood. Conclusion: Cows' milk consumption in early childhood was not protective against fracture in later childhood. These findings do not support increasing cows' milk consumption for fracture prevention.

Keywords: Cows' Milk
Fracture
Nutriton
Pediatrics
Prospective Studies
Advisor: Maguire, Jonathon L
The Effects of Faba Bean-Containing Pasta on Glycaemia, Satiety and Metabolic Control in Healthy Young Adult Males

The hypothesis that addition of faba bean (FB) flours and fractions into pasta reduces postprandial glycaemia and increases satiety has been tested in young adult males. Experiment 1 investigated the effects in young adult males. They consumed a serving of pasta made from (1) durum wheat semolina or substituted with 25% of flour from faba bean (2) split flour, (3) high starch fraction, (4) protein concentrate, or (5) protein isolate. Measurements included postprandial blood glucose, insulin, C-peptide, GLP-1 and PYY, and appetite and second meal food intake. Experiments 2A and 2B measured second-meal effects after an ad libitum or fixed size meal (12 kcal/kg). Addition of high protein faba bean flours reduced postprandial glycaemia, and second meal appetite, and increased PYY and C-peptide but did not affect insulin or GLP-1. Consumption of pastas with added faba bean protein can have value-added nutritional benefits compared to conventional pasta.

Keywords: appetite regulation
faba bean
glycaemic control
metabolic control
pasta
Advisor: Anderson, Gerald H.
Collective Cell Migration: Linking Interactions Between Local and Global Length Scales

Collective cell migration is important for development, tissue homeostasis, and invasion, but the underlying dynamics are still elusive. The objective of this work was to provide new insights by combining information from the local length scale (cell-cell interactions during rearrangement) with the global length scale (net dynamics of cellular streams). To analyze the local scale interactions, a Matlab GUI was developed to make the processing of movie frames possible, and additional scripts were created to convert cell pixel edges into vectorized edges, track the neighbouring cells over time. At the global scale, a hierarchal clustering method was adapted to determine if streaming cells were more likely to be paired, based on their movement signatures. We identified that cellular rearrangement is likely the rate limiting step affecting the collaborative behaviours of the cells and that cells in vitro exchange neighbours in a similar manner to that observed in vivo.

Keywords: Collective
Migration
Advisor: McGuigan, Alison
Designing for Disorder: The Mechanical Behaviour of Bioinspired, Stochastic Honeycomb Materials

In nature, structure, material and function are constantly evolving in tandem. This work employs polymer 3D printing to study new honeycomb materials inspired by disordered, hierarchical architectures in biomineralized organisms. The primary aim is to elucidate mechanical effects of structural order vs. disorder in natural cellular solids. New honeycomb materials are proposed with improved damage tolerance. A mathematical “regularity parameter” controls cell stochasticity. Uniaxial tension, compression and fracture experiments reveal significant crack path deviations and strain delocalization. These lead to enhancements in e.g. ductility and fracture toughness between 30-90% beyond periodic geometries. Optimal cell irregularities are suggested, revealing a relationship between damage tolerance and cell size. Conserving spatial density, hexagonal honeycombs composed of hierarchical micro-truss ligaments are also presented. Depending on design objective, 100% increase in compressive strength and three-fold energy absorption limits were achieved. These results comprise novel design spaces, where disorder and hierarchy are embraced as design variables.

Keywords: 3D printing
honeycomb
irregular
sandwich
stochastic
structural biology
Advisor: Hibbard, Glenn D
Hatton, Benjamin D
An Investigation of Near-Field Optical Scattering by Boron Nitride Nanotubes

A novel infrared (IR) pump-probe continuous wavelength (CW) technique based on scattering type near-field optical microscopy developed by the Walker group has demonstrated evidence of coupling between phonon modes and phonon polariton modes in boron nitride nanotubes (BNNTs). The first experiment presented in this thesis aims to replicate and extend the results obtained. This paved the way to the creation of an experiment to observe handed light scattering signals seen in the BNNTs arising from the difference in scattering by phonons of the IR laser field, oscillating between two different circularly polarized states. The second aim of this thesis is to present an introduction to an investigation of chirality in BNNTs with near-field optical scattering experiments with the ‘homemade’ scattering-type scanning near-field optical microscope (s-SNOM).

Keywords: Boron Nitride Nanotubes
Chirality
Near-field microscopy
Optical scattering signals
Pump-probe spectroscopy
s-SNOM
Advisor: Walker, Gilbert
Tools for Exploring Non-Synonymous Variation in Arabidopsis thaliana

High throughput sequencing has opened the doors for investigators to probe genetic variation present in large populations of organisms. In plants, the 1001 Genomes Project (1001genomes.org) is one such effort that sought to characterize the extant worldwide variation in Arabidopsis thaliana for future analyses to compare and draw upon. In my thesis I began the construction of a synthetic yeast pathway to test the effects of natural non-synonymous variants on the activation of the A. thaliana abscisic acid (ABA) signaling pathway in the hopes of characterizing variants that modulate pathway output. I constructed a series of expression cassettes to confirm the correct expression and localization of our ABA members and laid the groundwork for future members to continue constructing the pathway. Additionally, I created a web application called The Variant Viewer, for investigators to query the 1001 Genomes database and view variants in any A. thaliana gene.

Keywords: abscisic acid
arabidopsis
missense variant
online application
plants
synthetic biology
Advisor: Provart, Nicholas J
‘Sanctuary Toronto’: Municipal Authority, Policing Cities, and Residents with Precarious Immigration Status

On February 21, 2013, the City of Toronto became Canada’s first ‘sanctuary city.’ However, the City cannot claim to be a sanctuary city if the Toronto Police Service participates in immigration enforcement. This thesis examines the City’s jurisdiction and authority over the Police Service, and conversely, the legality of the Police Service’s practices of enforcing immigration status. Throughout this thesis, I point to an enduring tension between the City and the Police Service over their respective interpretations of jurisdiction and authority vis-à-vis non-status individuals. Drawing on academic literature, archival, policy, and legal materials, this thesis concludes that while the City’s jurisdiction and authority over the Police Service is limited, the Police Service’s legal arguments against sanctuary are inaccurate, and are thus insufficient reasons for refusing to comply with the City’s sanctuary policy.

Keywords: access without fear
immigration status
municipal authority
policing
sanctuary city
undocumented
Advisor: Flynn, Alexandra
Auto(decolonizing)ethnography of My Academic Selves and Practices

This decolonizing autoethnography hinges on Sandoval’s (2000) analysis of the metaphor of the mask by Franz Fanon (1967), to explain the different ways in which I understand and conceptualize my EFL teacher educator identity, both before coming to the University of Toronto (from 2011 to 2014) and during the coursework in the Language and Literacies Education program (from 2015 to 2016). Drawing from decolonizing and Indigenous epistemologies, an autoethnographic tapestry is woven to account for such transformations. Esta autoetnografía descolonizadora se basa en el análisis de Sandoval (2000) de la metáfora de la máscara por Franz Fanon (1967), para explicar las diferentes formas en que entiendo y conceptualizo mi identidad de formador de licenciados en inglés como lengua extranjera, antes de llegar a la Universidad de Toronto (desde 2011 a 2014) y durante los cursos tomados en el programa de Educación en Lenguaje y Literacidades (desde 2015 hasta 2016). Partiendo de epistemologías descolonizadoras e indígenas, se crea un tejido autoetnográfico para explicar tales transformaciones.

Keywords: autoethnography
Ch’ixi
decolonizing
EFL teacher educator
Fanon
haunting
Advisor: Gagné, Antoinette