VictorJuiz/thesis huggingface dataset:
Heat and Mass Transfer Around a Bubble on a Horizontal Surface in a Subcooled Flow
Keywords: Computational fluid dynamics
Fluid mechanics
Heat transfer with phase change
Horizontal surface
Multiphase flows
Subcooled boiling

Early state heat and mass transfer processes around a nucleated bubble in a subcooled flow boiling is studied numerically. The model uses both boiling and condensation processes, in which microlayer evaporation, thermal boundary layer conduction and kinetic theory evaporation and condensation heat and mass transfer mechanisms, are included. In addition, the model includes a microlayer thickness prediction. The model is applied on a two-dimensional and a three-dimensional computational domain at different subcooling temperatures and flow velocities in presence of gravity. The heated surface superheat and the system pressure are kept constant in all simulations. The two phase model, Volume of Fluid (VOF) in ANSYS/FLUENT is used. The results of the study show the importance of each of the heat transfer mechanisms in various stages of the bubble growth. At the early stages of the bubble growth, the microlayer heat transfer is the dominant transfer mechanism, however, as the bubble grows, the evaporation through bubble upper surface becomes significant. Furthermore, results indicate that the isothermal bubble assumption, which is used in prior models, is not valid for the whole life of bubble growth. The new bubble diameter correlation is concluded from theoretical analysis, which is the function of both √t and t with the coefficient of Ja and Pr numbers. The numerical model predicted bubble lift off diameter at p=2.5atm,〖∆T〗_sup=9℃,〖∆T〗_sub=15℃ is 0.36mm that is predicted experimentally 0.39mm at the same operating conditions. By 7% of underestimation of lift off diameter, the numerical model is validated.
The Cellular and Molecular Mechanisms of Ischemia-reperfusion induced Lung injury
Keywords: acute lung injury
cell death
ischemia reperfusion
lung transplantation

Lung transplantation is the last option to treat patients with end-stage lung diseases. One of the main problems of lung transplantation is ischemia-reperfusion-induced injury, which can cause primary graft dysfunction. Thus, it is pertinent that we better-understand the underlying mechanisms of IR-induced lung injury. In this thesis project, we investigated the cellular and molecular mechanisms of IR induced lung injury Protein kinase C (PKC) is involved in many pulmonary diseases and thus, may be a mediator of IR-induced lung injury. We found that over 500 genes related to TNF and NFκB are altered in human lung epithelial (BEAS-2B) cells after PKC activator stimulation. Furthermore, PKC activation induced apoptosis and cytokine production. Next, we investigated the role of protein kinase C delta (PKCδ), in IR-induced lung injury during lung transplantation. To study intrinsic cellular response of IR-induced lung injury, we designed a cell culture model that simulates the lung transplantation procedure. Using this model, we were able to replicate IR-induced cytokine production and necrotic cell death shown in animal/clinical studies. PKCδ inhibition by δV1-1 reduced inflammatory cytokine production and ER stress protein degradation, while changing the mode of cell death from necrosis to apoptosis. We further observed that PKCδ inhibition significantly improved lung functions in in vivo models, suggesting that PKCδ inhibition is a good therapeutic strategy to treat IR-induced lung injury. We also investigated the underlying mechanism of IR-induced necrosis. In lung transplantation procedures, necrosis is considered to be a major contributor to IR-induced lung injury. Using our simulated IR cell culture model, we found that necroptosis and calpain activation mediates IR-induced necrosis and mitochondrial dysfunctions. We also found that calpain activation promotes necrosome complex to translocate to mitochondria, suggesting that calpain activation is necessary for necroptosis signaling. Calpain also activates STAT3 phosphorylation and ER stress activation, implicating that calpain is the major player of IR-induced cell death. In this project, we found several mechanisms related to cell death and inflammatory response in IR-induced lung injury. Thus, my findings will be valuable information in the field of lung transplantation research and potentially introduce new therapeutic strategies to lung transplant settings.
Canadian Federalism, Abeyances, and Quebec Sovereignty
Keywords: Abeyances
Canada
Constitution
Federalism
Quebec

This dissertation examines the changing patterns of intergovernmental relations among political elites toward sensitive constitutional issues implicated in the Quebec sovereignty movement, in particular after the 1995 referendum on Quebec sovereignty-association. It extends David Thomas' concept of constitutional "abeyances" to suggest that areas of constitutional ambiguity over which there are strong enough disagreements to lead to a national breakup can be successfully managed given enough political will. This depends on their being enough political actors who otherwise share a common interest in national unity willing to keep abeyances from escalating into a crisis. The exposure and politicization of such abeyances in the middle of the 20th century raised the salience of constitutional disagreements in Canada nearly to the point of national disintegration. The decline in the salience of these abeyances and the waning of support for sovereignty in Quebec since the last referendum has reduced this possibility substantially. Using a mixed method approach within an historical institutionalist framework, this dissertation argues that, along with other social forces, this is partially explicable in light of the fact actors such as the courts, federalist political leaders, and their parties have been willing to avoid discussing sensitive constitutional abeyances and leave them unresolved in the interests of avoiding a constitutional crisis. This has certainly not resulted in end of the sovereignty movement in Quebec, which remains very much alive. However, along with other political and social forces the willingness to keep deep constitutional disagreements camouflaged has permitted Canadian federalism to regain a measure of stability.
Examining Child Welfare Outcomes for Asian-Canadian Children and Families: A Mixed Methods Study
Keywords: Asian
Child Protection
Child Welfare
Disparity
Disproportionality
Families

This three-paper dissertation triangulated three different data sources using mixed methods to build a comprehensive understanding of Asian-Canadian households involved in the child welfare system at the national and local levels. The first paper used a mixed method approach to build a descriptive profile of Asian-Canadian households involved in the child welfare system. The results from secondary data analysis using the 2008 Canadian Incidence Study of Reported Child Abuse and Neglect (CIS-2008) indicated substantive differences between Asian-Canadian and White-Canadian households investigated by child welfare agencies. These results were presented to focus groups consisting of child protection workers and community service providers, eliciting practice insights and improved understanding of child welfare decision-making. The second paper compared child maltreatment investigations in the CIS-2008 to Canadian Census child population data. The study found that Asian-Canadian households were under-represented in the child welfare system and had almost two times the odds of case closure after an investigation compared to White-Canadian households. Three different disparity indexes were used in the analyses: population-based, decision-based, and maltreatment-based. The results demonstrated the need for greater clarity and consistency in the definitions and methodology for examining racial disparity in child welfare research. The third paper used administrative child welfare data from the Ontario Child Abuse and Neglect Data System (OCANDS) to examine the decision to close after investigation rather than transfer to ongoing child protection services (CPS). Compared to White-Canadian households involved in the child welfare system, Asian-Canadian households received ongoing CPS for over a month longer and were almost half as likely to be re-investigated within one year after case closure. This suggests that child protection investigations involving Asian-Canadian households may not be closed prematurely, but rather, provided the necessary intervention. Together, the three papers examine the profile of Asian-Canadian households in the child welfare system as well as child welfare decision patterns and services provided to this group. The discussion section for each paper and the dissertation's conclusion summarizes the study results, limitations, and implications for social work and child welfare research, theory and practices.
A New Approach to Robot Manipulation
Keywords: Autonomous
Optimization
Reconfigurable
Robotics
Serial-Link-Manipulator

This thesis discusses a new approach to the design, development and configuration assignment of Reconfigurable Robot Manipulators. It details the engineering of a new Modular, Autonomously Reconfigurable Serial manipulator platform, termed the MARS Manipulator, as well as a systematic methodology for obtaining the optimum configuration given a user-defined task. The platform consists of i) an 18-Degree-of-Freedom (DOF) serial-link manipulator capable of locking any of its joints at any position in their continuous range, such that it can emulate lesser DOF serial manipulators with different kinematic and dynamic parameters, and ii) an integrated simulation and design environment that provides a toolset for the design, implementation and optimization of a desired manipulator configuration for a given task. The effectiveness of the MARS Manipulator to adapt its configuration to various tasks is examined by assuming two well-known configurations, SCARA and articulated, and by performing a specific task with each of them. The variation in effectiveness of the two configurations in terms of the end-effector trajectory, end-effector accuracy and power consumption is discussed. Further, these configurations are optimized with respect to their performance accuracy, and compared to their pre-optimized versions. Further, the simulation is validated against with the physical hardware prototype, running the same task. A method of determining an optimal configuration based on a user-defined task is presented, in which the joint space of the MARS Manipulator is treated as a 12-dimensional smooth configuration manifold. The manifold is discretized and ranked based on a variety of criteria, and then clustered into attractive and repellent regions. The user then specifies which regions are desired in the target configuration, and the manifold is reduced in dimension in order to maximize the number of attractive regions and minimize the number of repellent regions. Six manipulators were synthesized using this approach, and their effectiveness is compared.
Understanding your Education: Onkwehonwe and Guests Responsibilities to Peace, Friendship and Mutual Respect
Keywords: Guests
Indigenous Education
Indigenous Worldviews
Onkwehonwe

This thesis explores how Guest participants have engaged with Onkwehonwe (Original People in Mohawk) worldviews as they enrol within post-secondary courses about Onkwehonwe topics, taught by Onkwehonwe instructors/professors from Onkwehonwe perspectives. In order to acquire an understanding of what it means to be a Guest, I spoke to nine Elders and Traditional Teachers on expected Guest behaviour and actions. These teachings along with teachings of Wampum Belts were used to understand and analyze the stories of nineteen Guest participants. Grounded by Onkwehonwe worldviews, the methodology of this research project centered ceremony. The data collection method was storytelling in sharing circles. In hosting three large sharing circles and seven small ones, participants answered open ended questions. These circles were hosted in Toronto, Ontario between September 2014 and April 2015. The main findings of this thesis are 1) the primary, secondary and post-secondary education systems are not providing students with a historically accurate or relevant current education in relation to Onkwehonwe people, histories and topics; 2) when participants engaged in Onkwehonwe courses and pedagogies they all experienced a paradigm shift that lead to personal and professional growth; 3) this growth fuelled a desire to work in solidarity with Onkwehonwe peoples and a responsibility to share the learnings with other Guest people. This thesis is novel and contributes to scholarly discourse on Onkwehonwe research as it employs Onkwehonwe methodologies with Guest only participants (other than myself). It also offers the term Guest instead of using words like ‘non-Aboriginal’, or ‘settler’ and provides alternative ways of looking at Onkwehonwe/Guest relationships. In staying true to the data collection method of sharing circles, dissemination of the last question is as a sharing circle chapter. Individuals that are interested in how decolonial methodologies can have practical applications as well as those interested in Onkwehonwe/Guest relationships will find this work of interest.
Application of Gaussian Moment Closures to Three-dimensional Micro-scale Flows
Keywords: adaptive mesh refinement
computational fluid dynamics
Knudsen number
micro-scale
moment closures
Newton-Krylov

A parallel, implicit, adaptive mesh refinement (AMR), finite-volume scheme is described for the solution of the standard and regularized Gaussian moment closures on three-dimensional, multi-block, body-fitted, hexahedral meshes. The standard Gaussian closure has been shown to accurately predict non-equilibrium phenomena at moderate Knudsen numbers through an anisotropic treatment of pressure. The regularized closure builds on these advantages and includes the effects of non-equilibrium heat transfer by means of a first-order correction to the standard Gaussian closure. The combined moment closure treatment / numerical method is applied to the prediction of three-dimensional, non-equilibrium, micro-scale, gaseous flows. Unlike other regularized moment closures, the underlying closure is the standard maximum-entropy Gaussian closure which provides a fully-realizable and strictly hyperbolic description of non-equilibrium gaseous flows that is valid from the continuum limit, through the transition regime, and up to the free-molecular flow limit. The proposed finite-volume scheme uses Riemann-solver-based flux functions and limited linear reconstruction to provide accurate and monotonic solutions, even in the presence of large solution gradients and/or under-resolved solution content. A rather effective and highly scalable parallel implicit time-marching scheme based on a Jacobian-free inexact Newton-Krylov-Schwarz (NKS) approach with additive Schwarz preconditioning and domain partitioning following from the multi-block AMR mesh is used to obtain solutions to the non-linear ordinary-differential equations that result from finite-volume spatial discretization procedure. Details are given of the standard and regularized Gaussian closure, extensions for diatomic gases, and slip-flow boundary treatment. Numerical results for several canonical flow problems demonstrate the potential of the closures, that when combined with an efficient parallel solution method, provide an effective means for accurately predicting a range of fully three-dimensional non-equilibrium gaseous flow behavior.
Characteristics, Engagement and Academic Performance of First-year Nursing Students in Selected Ontario Universities
Keywords: Baccalaureate nursing program
NSSE
Nursing education
Ontario nursing
Student Engagement
student success

With an aging population nationally, nursing programs have struggled to meet the demand for nurses in our healthcare system. Student attrition remains high at 28% within the first two years of the Baccalaureate nursing programs. In order to meet healthcare system demand, nursing programs need to ensure that students persist, graduate, and are academically successful on the national examination. As a first step in student success, one needs to identify effective educational practices in first-year nursing programs that are associated with student engagement within the Canadian context. Extensive research in the U.S. has examined educational practices and student engagement. However, few national or international studies examined nursing student characteristics and engagement and student success. This study examined the extent to which first-year nursing students are engaged in effective educational practices and any relationships between student demographic, external, academic, social, and institutional variables, and student engagement. A descriptive correlational design was used to conduct a secondary analysis of pre-existing 2008 National Survey of Student Engagement (NSSE) data from nursing students in 13 Ontario Universities. Descriptive statistics were computed to examine student characteristics and the distribution of NSSE benchmark scores. Step-wise multiple regression analysis was used to identify relationships between predictor variables and student engagement and academic performance (grade point average). The results identified several significant predictors of first-year nursing student engagement including age, ethnicity, hours spent preparing for class per week, grade point average, hours per week spent participating in cocurricular activities, participating in physical fitness activities, and institutional size. Being a first-generation student and age were significant predictors of academic performance for first-year nursing students. The findings provide insight into some of the drivers of engagement in first-year nursing education and may also inform policy and practice for improving nursing student engagement and, ultimately, graduation rates.
Design of Ultra-wideband Reflectors
Keywords: antenna array
metasurface
reflectarray
wideband reflector

It is well-known that reflectarrays typically have a narrow bandwidth which is commonly attributed to the resonant nature of the antenna elements used and the narrow bandwidth of the phase shifting networks used. Typical approaches to increase the bandwidth include the use of true-time-delay (TTD) devices, coupling multiple resonances together, stacking multiple layer of scatterers or the use of numerical optimization techniques. While these approaches have been shown to improve the bandwidth of reflectarrays, the upper bound remains at approximately 40 in fractional bandwidth. This thesis investigates how ultra-wideband reflectors can be designed using novel approaches going beyond the conventional approaches listed above. Specifically, we investigate two new methods to design reflectarrays. In the first method, the reflector is designed as a Transformation Optics (TO) device and in the second method, the reflector is designed as a metasurface. The TO method amounts to manipulating of electromagnetic waves using an appropriate set of material parameters such that the wave propagation inside the material behaves in a desired manner. We use TO as a means to design an ultra-wideband reflector and draw insights into the practical considerations associated with designing such a reflector. In the second method, we design a reflectarray as a metasurface. Traditionally, reflectarrays are considered to be an array of individual antenna elements with no surface properties typically defined. A metasurface often has homogenized surface properties such as surface impedance and admittance which are realized by sub-wavelength elements that make up the reflector. A novel method to design ultra-wideband reflector using a metasurface is derived from first principles and it is shown that the designed reflector exhibits excellent characteristics over a very wide band of frequencies. The advantages and disadvantages of the reflectors designed using each of these two methods are discussed. A comparison of our metasurface is made to a state-of-the-art wideband reflectarray.
Tutoring Writing, Transmitting Culture: Investigating Tutors' and Students' Beliefs about Good Writing and a Writer's Voice in an Afterschool Literacy Program
Keywords: adolescent
literacy
tutoring
voice
writing

Using an ethnographic case study approach, this thesis investigates what multilingual adolescent writers and their adult tutors in an afterschool literacy program believe about good writing and a writerâ s voice, and how their beliefs about writing and voice both reflect particular linguistic and cultural values and shape attitudes towards language use, the writer, and writing development. Grounding the research in social constructivism (Vygotsky, 1980, 1986) and theories of language socialization (Duff, 2007a; Schieffelin Ochs, 1986), legitimate peripheral participation (Lave Wenger, 1991), and symbolic capital (Bourdieu, 1991, 2006), I addressed the following three questions: 1) What do tutors and students believe about good writing and a writer's voice? 2) How do tutors conceptualize their identities, purposes, and actions in responding to students' writing and voice in this context? and 3) In what ways do students see their tutoring sessions contributing to their overall development as writers? I observed 4 writing tutors and 5 of their students for 4 months, triangulating data that included observing and digitally recording the tutoring sessions; conducting semi-structured interviews and stimulated recalls with the participants; and collecting print-based materials produced by the participants. The findings show (a) that participants considered good writing as a moral imperative and that they saw good writing and voice both as interconnected and as something that produced writer capital; (b) that volunteers constructed an ad hoc tutoring identity marshaled from personal and professional experiences to tutor effectively; (c) that learning to write was a transformative, bidirectional undertaking with experts (tutors) being affected as much as novices (students); and (d) that students exhibited strong convictions over what makes an ideal writing tutor. These four observations suggest that writing and tutoring writing transmit cultural knowledge, language values, and principles of appropriate verbal and physical conduct.
Bisimulation-based Structural Summaries of Large Graphs
Keywords: databases
graph
multi-core
parallel
RDF
summary

With an increasing number of heterogeneous entity descriptions available as large graphs that grow to millions of nodes and billions of edges, it is a challenge to understand, explore, and query these large graphs. Bisimulation-based structural summaries have often been used as a compact representation of the dataset that can improve query performance. However, current bisimulation summary construction techniques for large graphs do not scale and do not facilitate the use of summaries within existing systems. We address these challenges with three contributions. First, we describe bisimulation summary construction techniques for large graphs that leverage a novel singleton optimization which drastically reduces construction time. Second, we show how structural summaries can be used to improve query performance within existing RDF systems. Third, we give an ontology for describing structural summaries as RDF that enables their use and verification with existing RDF tools. Our work also demonstrates that the S+EPPs system, built on top of existing RDF processors, is an efficient, scalable, and flexible approach to exploring and querying large graphs using bisimulation-based structural summaries.