VictorJuiz/thesis huggingface dataset:
Input/output harmonic free current link three-phase AC power supply

The three-phase current link AC to AC power supply, a relatively new topology for AC power supply application, has several potential advantages such as smaller number of magnetic components, lower switching frequency and more rugged operation. Despite this, it has received very little attention by the researchers, and the majority of work found in the literature is confined to the application of voltage type converters in this area. This thesis presents a comprehensive systematic approach for steady state/dynamic analysis and design of three-phase current link AC to AC power supplies. Concept of PWM methods in three-phase current type converters (CTC) is explained and the associated constraints in PWM pattern generation are addressed. Several PWM techniques are described and their performance from different aspects are compared. A steady state analysis is presented based on the Fourier representation of PWM waveforms which allows an accurate prediction of the relationships between the fundamental/harmonic components of the waveforms and other system parameters. Expressions governing various steady state characteristics of the system are derived. A dynamic model using the concept of local average of signals is established. The agreement between the dynamic behavior of switching system and derived model is illustrated. Phenomenon of multiple crossing is explained and the necessary requirement for avoiding such a phenomenon is obtained. The concept of internal model controllers is introduced and its application in the inverter control system for achieving zero steady state error is described. A detailed design procedure is presented. Root-locus method is used to design the system controllers. The applicability of different models in different design problems is discussed. All s-domain designs are verified by time-domain simulations. Experiments are conducted on a 2 KVA, 60 Hz to 50 Hz power supply. A 32 bit DSP-base high performance controller is used to implement the control system. The predicted steady state and dynamic results as well as the time-domain simulations are experimentally verified.
Development of a directional flow probe for the hypersonic regime

The hypersonic gun tunnel facilities at the University of Toronto Institute of Aerospace Studies were used to develop a probe capable of determining the velocity at a point within hypersonic flows. Investigations into the flow characteristics of the suggested probe demonstrated that the desired flow structure was established but that some unknown flow characteristics around the probe head may be present. A numerical solver was developed which uses the pressures measured by the probe to calculate the incident angles of attack and the Mach number of the flow. The nature of the system of equations makes the solution particularly sensitive to small perturbations in the relationship between the measured pressures. It was possible to successfully obtain pressure measurements that were consistent with theoretical expectations. Recommendations for further development and refinement of the probe are included.
Standing tall, an analysis of parents' evaluations of a walker for children with cerebral palsy

This thesis is derived from a larger study which evaluated the effectiveness of a new walking aid for children with cerebral palsy and other disabilities (Wright, Belbin, Jutai, Bortolussi & McKeever, 1997). Qualitative data were collected through interviews with 19 parents of children who had been using the aid for one year. These data were analyzed in two stages. First, the interviews were summarized and major themes were identified. Although improvements in walking were not dramatic, findings indicated that the children had benefitted physically, psychologically and socially from the aid. Second, a theoretical analysis was conducted using Bourdieu's concept of "habitus" or social position. Parents' descriptions of the esthetic qualities of the walker, and changes in physical comportment and behaviour, revealed their perception that the children's habitus had been altered positively as a result of using the aid. Implications for professional practice and future research are reviewed.
Validation of coupled heat and moisture flow program in unsaturated porous media

An historical overview of the developments of heat and moisture flow analyses in unsaturated media is compiled with specific reference to works by Philip and deVries, Milly, and Thomas and King. The potential/temperature based governing equations are developed independently and compared with those by other researchers. A numerical solution, TRUCHAMP, based on the integrated finite difference method, was developed to solve the equations for coupled heat and moisture flow problems. The model is verified by comparing its results against those established by other researchers. Excellent correlation is achieved for the base case defined by a set of boundary conditions and material parameters established for Leighton Buzzard medium sand. Sensitivity analyses are conducted on eight material parameters established in the governing equations and their results correlated with the base case at plus/minus twenty percent changes. This work serves as essential information for preliminary design of nuclear waste repositories.
Ischemic preconditioning of the myocardium, role of angiotensin II receptors

Adenosine A$\sb1$, $\alpha\sb1$-adrenergic and bradykinin B$\sb2$ receptors mediate ischemic preconditioning (IP) of the myocardium at least in part through a receptor-mediated protein kinase C (PKC) mechanism. Since angiotensin II (AII), which is released during ischemia, can activate PKC, it is possible that AII receptors participate in IP. To test this hypothesis, the ability of AII receptor stimulation or blockade to protect or abolish IP respectively, was assessed in isolated rabbit hearts. IP reduced infarct size significantly. Brief stimulation of AII receptors using AII (100nM) before the ischemic insult mimic the IP protection. Both non-selective inhibition of AII receptors with saralasin (1$\mu$M) and selective inhibition of AT$\sb1$ receptors with losartan (20$\mu$M) completely abolished IP. However, the IP protection was not blocked by PD-123,319 ditrifluoroacetate (10$\mu$M), a selective inhibitor of AT$\sb2$ receptors. Thus, activation of AT$\sb1$ receptors must occur for ischemic preconditioning to limit infarction.
Muslim students in public schools, education and the politics of religious identity

This study uses ethnogtaphic research methods to examine Sunni Muslim students and experiences as a religious minority in the public school system in Canada. Dominant norms and values are encoded into school policies, practices and curriculum. Many of these create areas of contention for Muslims. For Muslim students, the fundamental incompatibility between Islamic ideology and praxis and the secular public school system can create dissonance, alienation, and in many cases, a desire to conform to the cultural practices within schools and society, at the expense of an Islamic way of life. This study, however, focuses on those students who strive to maintain an Islamic identity and lifestyle and will examine how this informs their educational experiences. The focus will also be upon how education has become an arena for contemporary cultural politics, and how Muslims use their religious identities to challenge Eurocentrism in school policies practices, and curriculum.
Troubling images, reflections on photography, pedagogy and political practice

This thesis is a study in methodology. Avery Gordon has written, "In order to write within a question concerning exclusions and invisibilities... requires a methodology that is attentive to what can't be seen, but what is powerfully real; attentive to what appears dead, but is powerfully present; requires attending also to just what the subject of analysis is" (1990:493). Here, the 'subject of analysis' is a photograph of a dead woman which takes on multiple theoretical, ethical and political dimensions. I 'trouble' with this image in the attempt to lay out a framework for thinking about the relationship between reading practice, political practice--in the context of reproductive politics--and research. I am interested in how divergent readings of images can be understood and theorized within the context of particular political movements which (presumably) require investment in the articulation of a shared political agenda. Images-as-symbols of political struggle often speak to 'who' particular movements understand themselves to be. These images-as-symbols might also afford insight into how the 'subject' of political struggle is constructed--and might be continually re-(imag)ined--through particular representational strategies and practices of looking.
Synthesis of diquinanes and triquinanes via fragmentation chemistry of deltacyclanes

This thesis describes research carried out with the goal of developing synthetically useful chemistry from metal-catalyzed (2+2+2) homo Diels-Alder cycloadditions. Deltacyclane cycloadducts obtained from the Ni(0)-catalyzed homo Diels-Alder reaction of tert-butoxy norbornadiene and electron-deficient olefins are fragmented to diquinane and triquinane skeleta. Improvements in the oxymercuration of the cyclopropane moiety of deltacyclane cycloadducts, particularly hydroxymercuration, has led to efficient routes to mercury-substituted brendanols and brendanones. Reduction or functionalization of the organomercurial functionality provided demercurated brendanols and brendanones. Investigation of Baeyer-Villiger and alkoxy radical fragmentation of brendanones and brendanols respectively (with and without mercury substituents) has led to rapid, selective syntheses of functionalized diquinanes and triquinanes.
Role of citrate toxicity on cardiac excitation-contraction coupling mechanisms

It has been proposed that citrate inhibits contractile force by reducing L-type $\rm I\sb{Ca},$ independent of $\rm Ca\sp{2+}$ buffering (Hryshko & Bers, 1992). Using whole-cell techniques in rat ventricular myocytes, we found significant $\rm I\sb{Ca}$-rundown contamination in our recordings, despite attempts to minimize it. Based on perforated patch recordings, however, $\rm I\sb{Ca}$ did not change significantly with citrete $\rm(I\sb{Ca} = -5.2 \pm 1.1$ to ${-}6.1 \pm 0.7$ pA/pF; p $>$ 0.5, n = 3). Action potentials and single myocyte $\rm\lbrack Ca\sp{2+}\rbrack\sb{i}$ transients data were consistent with these findings. The mechanism of force inhibition was then studied using fura-loaded rat trabeculae, where a decrease in peak force (p $<$ 0.05, n = 4) was accompanied without changes in $\rm\lbrack Ca\sp{2+}\rbrack\sb{i}$ (p $>$ 0.1). Inhibition in force due to intracellular acidosis was ruled out. Using force-$\rm\lbrack Ca\sp{2+}\rbrack\sb{i}$ loops from CPA-treated trabeculae, citrate decreased F$\sb{\max}$ (p $<$ 0.05, n = 6) without changes in MFT Ca$\sp{2+}$ sensitivity (p $>$ 0.1). In conclusion, citrate inhibits force by reducing F$\sb\max$ without affecting cardiac $\rm I\sb{Ca},\ \lbrack Ca\sp{2+}\rbrack\sb{i}$ transients, or MFT Ca$\sp{2+}$ sensitivity.
Optimal delivery method for the fetus with meningomyelocele

Background. MMC is a congenital anomaly which leaves the spinal cord and nerve roots exposed through a bony defect in the spine, leaving infants at risk for infection, death, and paralysis. Objectives. To determine if prelabour Cesarean section (CS) is preferable to trial of labour (TOL), and if CS after TOL is preferable to vaginal birth (VB) for infants with MMC. Design. Retrospective cohort study. Methodology. Cases were identified at the birth hospital through a medical records search for infants born with the ICD-9 code 741 for spina bifida and then tracked to neurosurgical centres. Birth and neurosurgical data were collected on infants born with MMC over a 10 year period in Ontario. Results. 370 infants with MMC were identified. After exclusions (n = 89) and incomplete follow-up (n = 62), 219 remained (20 died in the birth hospital). Prelabour CS was associated with a lower risk of infection than TOL (8/46 (17.4%) vs 51/150 (34.0%), odds ratio (95% CI): 0.41 (0.18-0.94)). CS after TOL was associated with a higher mortality rate at 6 months of age than VB (10/43 (23.3%) vs 12/116 (10.3%), odds ratio (95% CI): 2.63 (1.04-6.63)). Conclusions. Although delivery by prelabour CS appears beneficial for the fetus with MMC, further analyses of the data, controlling for confounding variables, are required to confirm these findings.
Impact and freezing of molten tin droplets on a solid surface

The collision and freezing of molten tin droplets on a surface was studied. The objectives of this work were: first to examine the effect of substrate temperature, substrate material, and substrate geometry on droplet impact dynamics; second, to measure surface temperature variation during impact to estimate the thermal contact resistance at the droplet/substrate interface; and finally, to propose an analytical model to estimate solidification effect on the maximum droplet spread. Impacts on a stainless steel surface set at different temperatures showed significant effect of solidification on droplet impact; solidification restricted droplet motion, particularly in recoil. Substrate material had a less dramatic effect on droplet impact dynamics. The model of maximum spread with the effect of solidification agreed well with the experiments. Results of the images impacting on the step and incline surfaces showed complex fluid flow which can only be simulated by a numerical model.
Endothelial cell migration and cytoskeletal organization in situ

Many locomoting cells migrating on a two dimensional substratum exhibit a polarity whereby the centrosome and stress fibers are preferentially oriented at the front of the cell facing the direction of migration. Most vascular endothelial cells (ECs) at the edge of experimentally induced wounds have centrosomes oriented toward the wound in the direction of cell migration. Thus, the finding that the centrosomes in ECs of nonwounded aorta and vena cava were predominantly oriented toward the heart led to the hypothesis that ECs were migrating in this direction. To test this hypothesis, ECs in a segment of the rat abdominal aorta were labelled with a relatively non-toxic dye, 1,1$\sp\prime$-dioctadecyl-3,3,3$\sp\prime,3 \sp\prime$-tetramethylindocarbocyanine perchlorate (DiI), and the position of the labelled cells was determined 3 and 6 weeks later. The results obtained showed that the DiI labelled ECs in 72% of the abdominal aortas had migrated toward the heart and that none had migrated in the opposite direction. These results indicate that vascular ECs in the rat aorta are not stationary, as previously believed, but are migrating toward the heart. To determine whether the centrosomes and stress fibers in the migrating ECs in situ, as in ECs migrating in response to wounding, are preferentially oriented toward the heart, whole mounts of abdominal and thoracic rat aorta were double stained with sera that label centrosomes and with rhodamine phalloidin to label stress fibers. In both the thoracic and abdominal inferior vena cava and aorta of the weanling, young adult and adult rats the centrosomes in the majority of the ECs were located on the heart side of the nucleus. Moreover, most of the stress fibers in the majority of the aortic ECs, were also oriented toward the heart. The results presented in this thesis show that DiI labelled rat aortic ECs migrated toward the heart. Moreover, as in ECs migrating in response to wounding both the centrosomes and stress fibers in most of the migrating aortic ECs were preferentially oriented in the direction of migration, suggesting that they may be involved in defining the direction and providing the force for locomotion, respectively.
Parameter estimation and efficient implementation of affine transforms for digital images

The first part of the thesis presents a new decomposition scheme and a high quality interpolation algorithm for efficient affine transformation of digital images. The affine model accounts for 2-D projection of most complex 3-D motions such as translations, rotations, and scaling. Based on the proposed decomposition, the transform is completed by a sequence of 3-pass shearing and a scaling operation where each of them is one-dimensional in nature. A computationally efficient FFT-based implementation of this new algorithm is proposed. Experimental evidence shows that the proposed scheme is superior to the conventional 2-pass cubic method. The second part of the thesis presents a novel registration algorithm to estimate the six affine parameters which characterize the transformation between two digital images. The proposed estimation is area-based and it requires no feature points matching. It employs the log-polar resampling concept, together with the slice matching algorithm, and the cross-search methodology to estimate all the affine parameters. Adaptive thresholding and subpixel correction are also introduced to increase the accuracy. Simulations show that the proposed method is more effective and robust than the traditional two-slice matching algorithm.
Manufacturing optical fibre Bragg grating strain sensors with an excimer laser for high-strain, multiplexed embedded applications

Fibre optic Bragg grading sensors are ideally suited for applications where embedding the sensor directly within the structural material will enable useful measurements to be taken. The particular application envisioned is to embed the sensors within a pultruded tendon produced for the prestressed concrete industry. The sensors within a composite pultruded tendon will experience long-term high strains. Bragg gratings are written into the core of an optical fibre by ultra-violet radiation produced by an excimer laser. This process however, compromises the strength of the optical fibre and therefore severely limits the strain range and long term viability of this type of sensor in this type of application. Presented herein is the assessment of the UV-induced strength degradation and its effect on free and embedded strain gauges. A presentation of alternative methods of creating Bragg gratings without compromising the strength is also presented.
Understanding the symptoms experienced by individuals with lung cancer

A descriptive study using both qualitative and quantitative data collection methods was conducted to gain an understanding about patients' perceptions of their experience with symptoms of lung cancer. Twenty individuals with lung cancer were interviewed within 2 weeks following an initial visit at the cancer clinic, and 16 of the individuals were interviewed 2 months following the initial interview. Content analysis of the tape recorded interviews with the 16 participants who completed both interviews revealed that individuals with lung cancer experience a myriad of symptoms which change over time. Symptoms had a negative impact on their daily lives. Limited interventions were described to manage the symptoms associated with the disease, but the majority of interventions used were considered helpful. Implications for nursing practice and further research are included.
Calreticulin modulates cell adhesiveness

Calreticulin (CRT) is a mutifunctional, ubiquitously expressed Ca$\sp{2+}$ binding protein of the endoplasmic reticulin (ER). The ability of CRT to modulate cellular adhesion has created some controversy as to where, subcellularly the CRT protein functions in this capacity. I will show that the full length ER form of CRT is involved in cellular adhesion rather than a cytosolic form of CRT, as proposed by others. Overexpression of CRT results in increased cell adhesion which is visualized by increased cell spreading, actin stress fiber formation, fibronectin matrix deposition, reduced cell motility, and epithelial-like-monolayer migration. CRT overexpression coordinately increases expression of cytoskeletal proteins vinculin and $\beta$-catenin, and the cell surface protein N-cadherin, which can explain all the effects of increased adhesion. I propose that the effects of differential CRT expression are modulated by the ER localized CRT, and that this may be realized via ER-to-nuclear signal transduction.
Kitchen economics for the family, paid education leave and the Canadian Autoworkers Union

This thesis examines the Paid Education Leave (PEL) program of the Canadian Autoworkers Union (CAW), formerly the Canadian Region of the United Autoworkers Union (UAW). This four-week program takes place at the CAW Family Education Centre in Port Elgin, Ontario and potentially provides 90% of the CAW's members with class-based, union-centred, labour education. Interviews conducted with key CAW sources uncover PEL's historical roots. A chronicle of the struggle to establish PEL is detailed in relation to the International Labour Organization (ILO) Convention 140 on Paid Educational Leave. Thematic, oral-history interviews were conducted with six CAW Local 222 members, all former participants of PEL. Interviews are used to illustrate a detailed description of the program's pedagogy and curriculum. Interview respondents were General Motors (GM) of Canada workers located in Oshawa, Ontario. Several policy and programmatic suggestions are made, including increased understanding of, and elevated respect for, informal learning.
Comprehensive model of calender stacks for dynamic analysis and the prediction of offsets

In order to improve paper smoothness, newly formed paper is pressed in a calender stack before being wound. Variations in the paper thickness can occur if the stack vibrates. This vibration, known as barring, reduces the paper quality and can cause damage to the rollers if it continues for long durations. In some cases, the vibration can be minimized by reducing the feedback effect of the paper traveling from one nip to the next. This thesis provides a comprehensive model of the calender stack to determine the complex mode shapes and frequencies of vibration of a user defined system. The model uses Euler-Bernoulli beam elements to model the calender rolls and uses linear springs and proportional damping to simulate the paper. Using the vibration characteristics, the program then minimizes the vibration by varying the wrap length through offset selection. Several aspects that affect the optimization method are investigated, including the resolution of the search space, the number of mode shapes to be considered, the method of energy feedback calculation and the influence of damping.
Income-contingent loans: Implications for accessibility to post-secondary education in Ontario

This thesis will explore the implications for accessibility with the introduction of an income-contingent loan repayment program. I will examine some of the problems associated with repayment and default rates connected with the current loan programs available to Ontario students, which would be addressed by a new student aid system which takes into account a graduate's income in the establishment of repayment rates. This thesis will also explore the results of studies associated with determined and/or explaining enrollment patterns in Ontario universities, with the aim of determining the implications of future, substantial tuition increases which may accompany the implementation of a model of this new loan plan. As well, the ramifications of an income-contingent loan plan for women borrowers will also be considered.