VictorJuiz/thesis huggingface dataset:
Control and Automation of Fluid Flow, Mass Transfer and Chemical Reactions in Microscale Segmented Flow
Keywords: Carbon Dioxide
Gas-Liquid Solubility
Microfluidics
Quantum Dots
Segmented Flow
Switchable Water

Flowing trains of uniformly sized bubbles/droplets (i.e., segmented flows) and the associated mass transfer enhancement over their single-phase counterparts have been studied extensively during the past fifty years. Although the scaling behaviour of segmented flow formation is increasingly well understood, the predictive adjustment of the desired flow characteristics that influence the mixing and residence times, remains a challenge. Currently, a time consuming, slow and often inconsistent manual manipulation of experimental conditions is required to address this task. In my thesis, I have overcome the above-mentioned challenges and developed an experimental strategy that for the first time provided predictive control over segmented flows in a hands-off manner. A computer-controlled platform that consisted of a real-time image processing module within an integral controller, a silicon-based microreactor and automated fluid delivery technique was designed, implemented and validated. In a first part of my thesis I utilized this approach for the automated screening of physical mass transfer and solubility characteristics of carbon dioxide (CO2) in a physical solvent at a well-defined temperature and pressure and a throughput of 12 conditions per hour. Second, by applying the segmented flow approach to a recently discovered CO2 chemical absorbent, frustrated Lewis pairs (FLPs), I determined the thermodynamic characteristics of the CO2-FLP reaction. Finally, the segmented flow approach was employed for characterization and investigation of CO2-governed liquid-liquid phase separation process.The second part of my thesis utilized the segmented flow platform for the preparation and shape control of high quality colloidal nanomaterials (e.g., CdSe/CdS) via the automated control of residence times up to approximately 5 minutes. By introducing a novel oscillatory segmented flow concept, I was able to further extend the residence time limitation to 24 hours. A case study of a slow candidate reaction, the etching of gold nanorods during up to five hours, served to illustrate the utility of oscillatory segmented flows in assessing the shape evolution of colloidal nanomaterials on-chip via continuous optical interrogation at only one sensing location. The developed cruise control strategy will enable plug'n play operation of segmented flows in applications that include flow chemistry, material synthesis and in-flow analysis and screening.
The Role of Local Strains from Prior Cold Work on Stress Corrosion
Keywords: Alloy 600
Brass
Cold Work
Electron Backscatter Diffraction
Polychromatic X-ray Microdiffraction
Stress Corrosion Cracking

Several studies have recently reported that cold working exacerbates stress corrosion cracking (SCC) of materials in various environments, including those in which they were previously thought to be immune. While these studies usually consider cold work as a homogeneous effect, the presence of grain boundaries results in local strain concentrations that are inhomogeneously distributed within the microstructure. In order to understand the underlying mechanisms by which the local strains generated by cold work influences SCC, α-brass and Alloy 600 were used in this study. The microscopic changes in the local strains caused by cold work and by SCC were measured using electron backscatter diffraction (EBSD) and polychromatic X-ray microdiffraction (PXM). While the plastic strains were qualitatively expressed through the local misorientation calculated from the orientation data measured by both EBSD and PXM, the elastic strains were determined from the Laue patterns measured by PXM. The interaction between the local strains, and the crack initiation and propagation during SCC was studied by comparing the strain distribution from the same area measured before cold work, after cold work, and again after SCC. In this way, apart from obtaining insights on the interaction, the relative importance of pre-existing strain concentrations and those created by crack propagation can be identified. Additionally, statistical analysis of the EBSD data from uncracked and cracked grain boundaries in Alloy 600 showed the susceptibility of the boundaries to increase when they were surrounded by high local strain concentrations and when the grains sharing the boundary had similar deformation tendency, but to be independent of the grain boundary angle. Finally, one of the contributors for the changes in the strain distribution during SCC can be the corrosion process itself which was examined by intermittently measuring the changes in local strains caused by intergranular corrosion on an unstressed sample.
Essays in Volatility Modeling and Option Pricing
Keywords: Factor Structure
Option pricing
Variance Risk Premium
Volatility Modeling

The common thread that runs through my research is the implication of volatility dynamics for option pricing. In the first chapter of this thesis, my co-authors and I study the presence of a factor structure in equity options. A principal component analysis of equity options reveals a strong factor structure. Guided by this finding, we develop an equity option valuation model that captures this factor structure. The model allows for stochastic volatility in the market return and also in the idiosyncratic component of equity returns. The model has a series of predictions relating individual firm's beta to patterns in implied volatilities. The equity option data support the cross-sectional implications of the estimated model. In the second chapter, I focus on the impact of intermediaries' risk sharing capacity on index options. I examine how inventory risk and market-maker wealth jointly determine the value of index options through their effects on the variance risk premium. My analysis shows that part of the variance risk premium compensates option market-makers for their exposure to market variance. Based on these findings, I develop a theoretical model in which market variance is stochastic and the representative market-maker accumulates inventory over time by absorbing end-users' net demand for index options. Starting from the market-maker's optimal trading strategy, I derive an explicit formula linking the variance risk premium to inventory risk and market-maker wealth. The model predicts that the variance risk premium is influenced by the ratio of inventory risk to the market-maker's wealth. Estimating the model on S 500 index returns and options, I find that it performs well.
Promisingness Judgments as Facilitators of Knowledge Building in Elementary Science
Keywords: competencies
design
innovation
knowledge building
knowledge creation
learning technologies

Recognizing promising ideas is an important component of expertise and creativity (Bereiter Scardamalia, 1993; Csikszentmihalyi, 2009; Gardner, 1994). The goal of this research is to explore students' intuitive understanding of promisingness and to build and test pedagogical and technological supports to enhance promisingness judgments. Toward this end, a "Promising Ideas" tool was developed and continually revised following a design-based research approach involving three cycles of design experiments. The earliest pilot showed students at upper elementary grade levels tended to judge as promising "important facts" as opposed to "ideas with knowledge building potential" in their selections of promising ideas in peer-generated online discourse. A later exploratory study found meaningful socio-cognitive configurations conducive to effective promisingness judgments. With this understanding, in the second design cycle, pedagogical supports were designed around the Promising Ideas tool and subsequently tested in a grade 3 class where students selected promising ideas from their own written online discourse, knowing in advance that selections would influence the direction of their work. After making selections they discussed top highlights across all classmate selections and narrowed their choice to the most promising ideas to serve as the basis for their next knowledge building efforts. In this study, they completed two cycles of this selection process. Qualitative and quantitative results suggest that students as young as 8 years of age made promisingness judgments that led to greater knowledge advances than same-age students, same topic, more experienced teacher, but without use of the promisingness tool and related discussion. These grade 3 students were able to direct their work in fruitful directions and additionally engage in productive collective decision making. In addition, individual differences among students were revealed and prompted me to explore the linkage of personal epistemic beliefs and promisingness judgments in the third design cycle. With further refined tool and pedagogical supports, the third design cycle engaged a grade 6 class in a similar process of promisingness judgments. Besides confirming knowledge advances in knowledge building work, students' epistemic beliefs were found co-developing with their knowledge of promisingness and conceptual change. In summary, the thesis explores theoretical isasues and implications for future pedagogical and technological developments to facilitate promisingness judgments through collaborative knowledge building.
Black Males' Perceptions of and Experiences with the Police in Toronto
Keywords: Black Males
Critical Race Theory
Mixed Methods
Policing
Race
Youth

Canada is commonly depicted as a diverse and tolerant immigrant-receiving nation, accepting of individuals of various racial, ethnic, and religious backgrounds. Nevertheless, Canadian institutions have not been immune to allegations of racial bias and discrimination. For the past several decades, Toronto's Black communities have directed allegations of racial discrimination at the police services operating within the city. Using a mixed-methods approach, this thesis examines Black males' perceptions of and experiences with the police in the Greater Toronto Area. In order to provide a comprehensive examination of this issue, this thesis is comprised of three studies with three distinct groups of Black males. The first of these three studies utilizes data from a representative sample of Black, Chinese, and White adults from the Greater Toronto area to examine racial and gender differences in perceptions of and experiences with the police. The second study draws on data from a sample of young Black men recruited from four of Toronto's most disadvantaged and high crime neighbourhoods to examine the views and experiences of those most targeted by the police. The final study involves interviews with Black male police officers in order to draw on the perspectives of those entrusted with enforcing the law. In line with a mixed-model hypothesis, the findings suggest that Black males' tenuous relationship with the police is a product of their increased involvement in crime, as well as racism on the part of police officers and police services. Using insights drawn from Critical Race Theory, I suggest that both the increased levels of crime and the current manifestations of racism have a common origin in Canada's colonial past.
Conserved Molecular Factors: Role of the Snail Family of Transcription Factors and the Fat Family of Atypical Cadherins in Cortical Development
Keywords: Apoptosis
Cell cycle
Cortical precursors
Fat atypical cadherin
Neural stem cells
Snail transcription fact

Recent research is beginning to show that the molecular factors that regulate stem cells in lower organisms are conserved in mammals, where they play similar, and equally important roles during development. We have asked whether the role of the Snail family of transcription factors, and the Fat family of atypical cadherins is conserved during neural precursor development from invertebrates to mammals. Specifically, we have shown that the Snail transcription factor is able to promote both cortical precursor and newborn neuron survival in the developing embryonic cortex in a p53-dependent fashion, while it is also able to regulate the proliferation of radial glial precursors through a Cdc25b-dependent mechanism. Loss of Snail led to a robust decrease in intermediate progenitors, which could also be rescued by Cdc25b overexpression. These perturbations in embryonic cortical development persisted throughout the life of the brain, with aberrant post-natal and adult neural precursor cell maitenance. These results clearly illustrate a conserved role for Snail in neural precursor cells throughout mammalian life. Next, we asked whether the atypical cadherins Fat1 and Fat4 have a conserved role in mammalian cortical precursors. We show that Fat1 and Fat4 control radial precursor cell maintenance in a cell autonomous manner, which is enhanced upon coincident loss of these two Fat family members, and this genetic interaction is likely explained by the physical interaction of Fat1 and Fat4 with one another that we have shown. Lastly, we show that loss of Fat1 and Fat4 leads to altered neuronal polarity. Taken all together, our work shows that Snail and the atypical cadherins Fat1 and Fat4 are conserved and play a functional role in neural precursors from invertebrates to mammals.
Selenophene-Thiophene Copolymers
Keywords: Block copolymers
Conjugated polymers
Organic electronics
Phase separation
Selenophene

The research described in this thesis involves the synthesis and characterization of selenophene-thiophene block copolymers.Chapter 1 serves as a general introduction. It describes the synthesis of poly(3-alkylthiophene)s (P3ATs), including early synthesis of P3ATs and the development of the Kumada catalyst transfer polymerization (KCTP) method. It then describes the fabrication and characterization of organic photovoltaic (OPV) devices and parameters that can be controlled by polymer design. Finally, it serves as a brief review of selenophene-based materials.Chapter 2 describes the first synthesis of poly(3-hexylselenophene)-block-poly(3-hexylthiophene) (P3HS-b-P3HT) by KCTP and describes the optoelectronic character of the copolymer. It demonstrates the phase separation of the copolymer in thin films - the first example of a π-conjugated block copolymer which undergoes phase separation based on the identity of the heteroatom in the heterocycle. Phase separation is confirmed by a combination of thin film absorption, atomic force microscopy, and energy dispersive X-ray spectroscopy.Chapter 3 describes further investigation into P3HS-b-P3HT block copolymers. The variation of molecular weight and selenophene content is investigated. The polymers are characterized by optical absorption spectroscopy, differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD), and cyclic voltammetry. Solution-phase self-assembly is also investigated and correlated to both molecular weight and selenophene content. Chapter 4 discusses modifying the morphology of selenophene-thiophene block copolymers through side chain engineering. The 2-ethylhexyl side chain is introduced to decrease rod-rod interactions, and resulting optoelectronic and physical properties are investigated. Variation of side chains results in different morphologies, which are imaged by electron microscopy. Poly(3-hexylthiophene)-b-poly(3-(2-ethylhexyl)selenophene) is demonstrated as one of the few known block copolymers to form a lamellar morphology with long-range (micrometer) order.Chapter 5 features statistical copolymers of 3-heptylselenophene and 3-hexylthiophene synthesized by KCTP. Optoelectronic properties are investigated and the copolymer crystallinity is demonstrated by WAXD and DSC. 3-Heptylselenophene is shown to be more compatible than 3-hexylselenophene with 3-hexylthiophene due to a more similar interlayer spacing dictated by the alkyl side chain. OPV device performance is presented, and the copolymer is shown to act as an average of both homopolymers, harvesting a broader range of photons.Chapter 6 summarizes the work described in this thesis, highlights advantages of selenophene-thiophene copolymers, and discusses further research that can be carried out on these copolymer systems.
Health, Risk, and Justice
Keywords: Bioethics
Distributive Justice
Equality
Health Care
Political Philosophy

While citizens in a liberal democracy are generally expected to see to their basic needs out of their own income, health needs are an exception. Most rich liberal democracies provide their citizens with health care or health care insurance in kind. Many people find this special treatment for health care appealing, but political philosophers and bioethicists have struggled to justify it. Most theorists hold that it is justified by the moral importance of health, but this approach has many flaws, not least of which is the fact that access to personal health care services is in fact a relatively inconsequential determinant of population health. This dissertation offers a new justification for health care entitlements. Health needs are not more important than other basic needs, morally speaking, but they are more unpredictable. I argue that health care entitlements are best justified in terms of risk management rather than health equalization or health promotion. Citizens ought to have insurance against health risks to provide stability in their future expectations and thus to protect their capacities to form, revise, and pursue a rational plan of life. The failure of private markets to deliver adequate access to health care insurance provides a rationale for state involvement in the delivery of health care. This approach provides tidy answers to some pressing problems in macro-level bioethics, but it has implications for political philosophy as well. One of the most important functions of the modern state is to provide citizens with security against various risks, including health risks, and yet this function is conspicuously absent from John Rawls's influential theory of justice. My dissertation begins the work of integrating security from risk into a liberal-egalitarian theory of justice.
Forbidden Access? Exploring the Nature of and Access to Culturally Pertinent Psychotherapy for Indigenous Latino Border-gender Youth Living in Toronto
Keywords: community counselling
Latinos in Canada
LGBTQ
psychotherapy
social psychology
trans-youth

Indigenous Latino border-gender youth form the fastest growing refugee seeker population in Canada. Indigenous Latino border-gender residents in Canada between the ages of 16 and 29 have a higher prevalence of mental health problems than their non-Indigenous trans-youth counterparts. Furthermore, there is a gap in culturally specific mental health services for Latino border-gender youth who do not access or remain in mainstream counselling services, despite this high prevalence of mental health problems. Currently, very little is known about their experiences of mental health services, and even less is known about how their identities as Indigenous affects these experiences. This study aimed to answer the following question: What are the intersections of cultural identity and counselling experiences for Indigenous Latino border-gender youth as they relate to mental health access? The study employed a qualitative narrative inquiry methodology, in which six Latino border-gender youth were interviewed and the data analyzed using a narrative story map tool. Overall results include metathemes of spirituality; trust and leadership; and, gender transition and the immigration process. The results will be used to inform counselling programs and services for Indigenous Latino border-gender youth and reduce the gap in service for this population.
The Nature of Selection on Flowering Time: Integrating Fitness Contributions through Male and Female Function
Keywords: Flowering time
Natural selection
Paternity analysis
Phenology
Within-plant variation

A central goal of evolutionary biology is to identify traits under selection and the causal mechanisms linking these traits to fitness. Most work towards this goal in plant systems has addressed the female component of fitness only. This thesis investigates the nature of selection on the timing of flowering onset - a trait of practical and theoretical importance - with equal emphasis on female and male function. The potential male fitness effects are many. First, flowering time may directly (or indirectly through correlation with another trait) influence ability to sire seed (e.g. by affecting pollen quantity). Second, because plants tend to mate assortatively by flowering time, an individual's flowering time might covary with the quality of dam it pollinates. Third, because flowering time partly determines the specific date range over which an individual reproduces, it may covary with exposure to pollinators, herbivores, abiotic stress, and other environmental characteristics that could affect fitness. I investigated these hypotheses through numerical modeling and experiments with the annual plant
Understanding the Human Side of School Leadership: Improving Teacher Morale, Efiicacy, Motivation and Commitment
Keywords: school leadership
teacher burnout
teacher commitment
teacher morale
teacher performance

Finding a clear connection between principal actions and student achievement has proved remarkably difficult for educational researchers. Recently, a strong base of evidence has emerged suggesting that principals working indirectly through their teaching faculties can lead to improved student achievement. What constitutes the most effective sort of humanistic and supportive leadership - how exactly principals might lead more effectively through others - has become the research agenda. Recent empirical work illustrates that principals who lead through humanistic approaches can have a positive impact on student achievement in their schools. But what is not clearly known is exactly what `leading with teacher emotions in mind' might actually look like; how can leaders ensure that faculty are emotionally well-served, possessed of a sense of efficacy, and committed to classroom success? The purpose of this qualitative research study was to understand the effects principals have on teacher emotions. What do teachers themselves report leaders do that improves teacher morale, commitment, and efficacy? To the extent that these questions retrace some of the emerging work of the field, they are confirmatory; to the extent that they elicit new responses, they are exploratory.The research was based on interviews of 20 teachers working in secondary schools in Southern Ontario, Canada. Teachers reported that principal behaviours were central to their emotions, and often shaped their morale, efficacy, stress, commitment, and motivation. Key principal behaviours include: showing professional respect for teachers; encouraging and acknowledging teacher effort and results; providing appropriate protection; being seen; allowing teacher voice; and communicating principal vision. The thesis concluded that these behaviours suggest a natural path for school principals to work through the teachers in their school, and represent a meaningful indirect impact of leadership. Further research was recommended to establish the effect size of these principal behaviours, and determine if they apply across jurisdictions, school settings, and different age panels.