VictorJuiz/thesis huggingface dataset:
Spatially Varying Saturation Pulse (SVSP) for Fat Suppression in Breast MRI
Keywords: breast imaging
fat suppression
MRI
spectral spatial pulse

Achieving reliable fat suppression with high water signal in a clinically acceptable scan time remains a challenge in breast Magnetic Resonance Imaging (MRI). To improve fat saturation in the presence of field inhomogeneity, a spatially-varying saturation pulse (SVSP) is proposed. This work introduces a design methodology for creating SVSPs and describes a practical implementation on a clinical whole body 1.5T MRI scanner. Both simulation experiments with a virtual breast phantom and 1.5T imaging experiments using a phantom test object containing both fat and water were used to demonstrate the feasibility of the proposed method. Initial results indicate that the proposed SVSP method can improve the reliability of fat suppression compared to Spectral Fat Saturation, while using similar pulse durations and exciting similar levels of water signal. SVSP shows promise in terms of its applicability to the clinical setting.
Intraspecific Variation in Leaf and Root Traits across Nutrient and Light Gradients in Coffee Agroforestry Systems
Keywords: agroforestry
coffee
Erythrina
functional traits
leaves
roots

Functional traits can evaluate crop responses to farm-level management practices, however there are considerable uncertainties as to the extent and drivers of trait variation. In a coffee agroforestry system I examined three shade and four nutrient treatments, in order to i) quantify intraspecific trait variation of coffee leaves and roots along soil fertility and light gradients, and ii) test if the functional biology of coffee, as described by its position along a known functional trait spectra, is best predicted by soil nutrients or light. Low light led to high intraspecific variation within plant photosynthetic rates while high light systems resulted in reduced intraspecific variation across all leaf traits. High fertilization produced lower amounts of intraspecific root variation. Finally, functional traits correlated along a resource gradient as expected. Agroforestry systems then have the potential to increase within species variation, which has important long-term consequences for the structure and function of agroecosystems.
Benefits and Challenges of Teacher Professional Learning in a Mathematics Intervention Study in the Early Years (JK-Grade 2)
Keywords: early years math
intervention study
JK-Grade 2
Ontario
professional learning
spatial reasoning

Research shows spatial reasoning and an early start to mathematics are key predictors of later school success. This thesis explores educator learning in a professional learning intervention study, focusing on spatial reasoning tasks. A team of JK-Grade 2 teachers, early childhood educators and a math coach spent time implementing a series of playful, research-developed spatial reasoning tasks in mathematics. Educator learning throughout this process was considered, with particular focus on two cases: a kindergarten teacher and a math coach. Results indicate several benefits to educator learning, including learning by observing children, through implementation of research-developed tasks, about mathematics content, and through personal reflection. The co-creation of tasks was highlighted as extremely important for educator learning. It is important for educators to co-create tasks instead of simply implementing existing ones. This intervention study also highlighted some challenges of teacher professional learning, including time, administrator support, educator perceptions and implementation of tasks.
Shear Performance of Heavily Reinforced High-strength Concrete Coupling Beams
Keywords: Coupling Beams
Reinforced Concrete
Shear
Side Cover Spalling

High-strength, heavily reinforced concrete coupling beams that have compact designs are critical to the building economics of high-rise structures. There is concern with these heavily reinforced designs that the phenomenon of concrete side cover spalling may occur as the coupling beams approach failure, causing an unintended loss of strength and stiffness. To investigate these consequences, four full-scale coupling beams with varying concrete strengths, reinforcement ratios, and side cover thicknesses were tested. It was observed that the concrete side cover spalled for all four specimens. In situations where the beam design capacity is close to the upper limits of shear capacity, a significant reduction in strength could occur as the concrete crushes before the stirrups yield. While the CSA Code had an average test-to-prediction ratio of 1.05 for the specimen peak load, the limits imposed by the ACI Code under predicted the peak load with test-to-prediction ratios as high as 1.45.
An Examination of the Role of Silicate in Sodium Transport and Salinity Tolerance in Rice (Oryza sativa)
Keywords: apoplastic bypass
rice
salinity
silicate
silicon
sodium transport

Silicate (Si)-mediated alleviation of salinity toxicity in rice is proposed to occur through a decrease in apoplastic sodium (Na+) transport. This is said to decrease shoot Na+ accumulation, a commonly proposed salt tolerance strategy. To investigate this, salt-tolerant (Pokkali) and salt-sensitive (IR29) rice cultivars were grown in 0 or 1.67 mM Si over a range of Na+ concentrations, and cultivar-specific effective concentrations of Na+ at which shoot fresh weight was decreased by 50% were determined. Within this experimental framework, salinity tolerance strategies were characterized using the radiotracer 24Na+ along with electrophysiological, photometric, and fluorescent dye measurements. Si treatment was found have no effect on transmembrane ion currents while decreasing shoot Na+ accumulation by over 50% in both cultivars. Si-treated IR29 exhibited lower apoplastic bypass and shoot Na+ flux. In Pokkali, examinations of Na+ influx, efflux, and shoot-to-root recirculation were unable to reconcile differences between shoot Na+ content and tracer-flux analyses.
Prediction of Blast-induced Ground Vibration and Rock Fragmentation by Statistical and Combined Finite-discrete Element Modelling Methods for the McGill Utility Tunnel
Keywords: Blasting
Combined finite-discrete element modelling
Ground vibration
Rock fragmentation
Tunnelling

The prediction of blast-induced ground vibration and rock fragmentation at the McGill Utility Replacement Tunnel was investigated using two techniques: empirical peak particle velocity prediction formulae and combined finite-discrete element method (FDEM) modelling. A statistical analysis of ten scaled-distance empirical formulae was performed by fitting them to 269 vibration recordings and assessing the quality of fit with seven statistical indices. In the FDEM studies, a transient blast loading function was developed for explosive product gases by idealizing explosive detonation and depressurization as the injection and expansion of gas into a borehole. With calibrated material properties and blast loading functions, stress-wave induced tensile and shear fracturing were replicated for a single blasthole. Moreover, synthetic fragmentation patterns and velocity-time histories were produced in simulations of blasting round BR-T66. The influence of free surface wave reflection and material impedance constrasts on ground motion amplification was investigated by comparing recorded and synthetic velocity-time histories.
Application of Mobile Phone-based ECG, Heart-rate and Physical Activity Monitor for Heart Failure Management
Keywords: Heart failure
Heart rate monitor
Smartphone Application
Wireless Wearable

Heart failure (HF) is the main cause of mortality in North America and it has a significant social and economic cost. As recent studies indicate, there is a relationship between heart rate at discharge time and mortality and hospitalization in patients with HF. Hence, heart rate could be monitored as another clinical indicator in HF patients transitioning from hospital to ambulatory care. Current heart rate monitors mostly have one of the following issues: 1) they are used in clinical setting and lack the user-friendly interface for a continuous monitoring system, 2) or designed to be used as wellness devices and not validated against clinical gold standard systems. This work describes the design, development and evaluation of a wearable heart rate and ECG monitoring system called BeatHR that allows patients to monitor heart rate in an ambulatory setting. BeatHR is able to capture and stream ECG signal and heart rate values in real-time via using a chest patch and a smartphone application. It also allows the user and their clinician to review the heart rate values above a pre-defined threshold, which could be defined based on the user's condition. The BeatHR system was compared to a clinically accepted gold standard, Holter monitor, and was found to generate comparable result overall with Intra-class correlation coefficients as high as 0.954.
Synthesizable FPGA Fabrics
Keywords: ASIC
FPGA
VTR

With increasing effort required for custom layout in deep-submicron technologies, we consider implementing field-programmable gate arrays (FPGAs) using standard cells. First, we extend the open-source Verilog-to-Routing (VTR) FPGA architecture evaluation framework to generate synthesizable Verilog for its architectural device model. Verilog can then be synthesized into standard cells, placed and routed using application-specific integrated circuit (ASIC) design tools. A second extension to VTR generates a configuration bitstream, used to configure the FPGA with user's circuit. The proposed framework and methodology opens the door to silicon implementation of a wide range of VTR-modelled FPGA fabrics. In an experimental study, several FPGA implementations synthesized in 65nm TSMC standard cells are compared with a 65nm Altera commercial FPGA. Finally, we consider augmenting the generic standard-cell library from TSMC with a manually designed and laid-out FPGA-specific cell. We demonstrate the utility of the custom cell in reducing the area of the synthesized FPGA fabric.
Developing a Knowledge-Based Evaluation Tool to Support User Selection of Interior Finish Materials
Keywords: End-Users
Evaluation Tool
Interior Finish
QFD
Selection
TOPSIS

Choosing the appropriate material that satisfies facility end-users and project requirements has become a difficult task. Due to their lack of knowledge on building materials and ineffective communication methods, end-users are often not involved in facility designs. This research aims to formalize a knowledge-based evaluation tool for interior finish materials used for floors, walls and ceilings which can be easily accessible by users. The evaluation tool adapts techniques of Quality Function Deployment while combining the multi-criteria decision analysis method, TOPSIS, to calculate the score of interior finish materials specific to each user. In addition, the evaluation tool becomes a database for users to gather information on common interior finish materials. Users will be able to evaluate finish materials and make their selection on which material they most prefer. The tool acts as a template for end-user education while becoming an effective communication method that can adhere to project requirements.
Gradient-doped Thermophotovoltaic Devices based on Colloidal Quantum Dots
Keywords: Colloidal quantum dot
Effective force field
Gradient-doped
Infrared
Thermophotovoltaics

Electromagnetic radiation emitted from hot objects represents a sizeable supply of energy; however, even for relatively hot bodies, its flux peaks in the short-wavelength infrared between 1 and 3 µm, standing in the way of its photovoltaic harvest using the most widely-available optoelectronic materials such as Si and CdTe. Colloidal quantum dots combine low-cost solution-processing with bandgap tunability in this spectral region, thereby offering a route to harnessing thermal power photovoltaically. Here we report thermophotovoltaic devices constructed using colloidal quantum dots that harvest infrared radiation from an 800°C blackbody source. Only by constructing a gradient-doped colloidal quantum dot thermophotovoltaic device were we able to achieve thermophotovoltaic power generation with a power conversion efficiency of 0.39%. The device showed stable operation at ambient temperatures above 100°C.
Quantifying the Effect of Sampling Gear and Effort on the Index of Biotic Integrity in two Huron-Erie Corridor Areas of Concern
Keywords: Areas of Concern
fish community assessment
Index of Biotic Integrity

The Detroit and St. Clair rivers were identified as Areas of Concern (AOC) in response to losses in critical fish and wildlife habitat. Implementation of remedial action plans required aquatic monitoring of AOCs using the Index of Biotic Integrity (IBI), a multi-metric index for biological assessment. In this study, three methods of calculating the IBI were applied to fish communities sampled using two different gears to determine the influence of scoring and sampling methods on IBI scores. IBI score variance between sites was also examined to determine the influence of sample effort. The results revealed that the IBI was not sensitive to gear type in either rivers due to varying catchability of species for each gear type. No significant difference was found between the three methods of IBI calculation. IBI score variance determined that current sampling protocols reduce the variance of mean IBI scores within a river by ~75%.
Hydrodynamic Force-transduced Cyotskeletal Remodeling Stabilizes Leukocyte Integrin-mediated Adhesions
Keywords: Actin Cytoskeleton
Cell Adhesion
Hydrodynamic Force
Inflammation
Integrins
Leukocytes

The emigration of monocytes from the blood into tissues is a fundamental component of inflammation. Monocytes roll and arrest on inflamed endothelium and stably adherent cells are subjected to a hydrodynamic force imparted by flowing blood. We used parallel plate flow chamber assays and confocal imaging to investigate actin cytoskeleton dynamics in the stabilization of integrin-mediated adhesion. The ability of U937 cells to resist detachment and flow-induced cell deformation when adhered to surfaces coated with VCAM-1 and ICAM-1 was dependent on actin polymerization. Hydrodynamic force triggered cytoskeletal remodeling, cell spreading and increased contact area with the adhesion surface. This force-induced signaling also occurredin the absence of integrin ligands. Our data suggest that hydrodynamic force induces integrin-dependent and -independent signaling that contribute to cytoskeletal remodeling, strengthening of cell adhesion and resistance to deformation whichenable U937 cells to stabilize their adhesion in the presence of hydrodynamic force.
Recovery from Concussion in a Cohort of Male High School Students
Keywords: adolescent
Concussion
management
mild traumatic brain injury
school
student

Historically, concussion research has focused on adult populations, but research on high school students is lacking. A retrospective and prospective longitudinal cohort design was used to describe recovery time from concussion and the contribution of history of learning difficulty, history of concussion and school grade of student on recovery patterns in a cohort of 116 male high school students. Significant differences were identified in recovery patterns for youth in this sample expressed as median days to medical clearance 31.5 (range= 5 - 271), as compared to the 7-10 day recovery for adults that has been previously reported in the literature. A history of learning difficulty and history of concussion were significantly associated with increased length of days to medical clearance in the study cohort. Understanding differences in recovery patterns as well as risk factors for prolonged recovery can contribute to more realistic management expectations for high school students.
Simulation of High-frequency Scaling of Silicon MOSFETs and the Golden Transistor
Keywords: Density Functional Theory
FDSOI
High frequency
METFET
MOSFET scaling
TCAD

This thesis investigates high-frequency scaling of advanced Silicon UTBB-FDSOI MOSFETs using semi-classical and ab initio NEGF simulations for the first time. Similarly, new ab initio NEGF simulations of the novel post-CMOS Au metal-channel FET are presented along side fabrication experiments towards testing simulation accuracy. Ab initio NEGF simulations predict short channel effects to be suppressed down to LG=2nm, TSi=1.2nm, with improved ION by 80% and gm by 308% to compared to 24nm UTBB-FDSOI MOSFET measurements. Semi-classical simulations predict improvements of 46% in gm and 75% in fT for scaling down to LG=9.7nm, TSi=3.1nm. The Au METFET shows no significant ION/IOFF with results being sensitive to simulation model choice. A complete METFET fabrication process flow is presented to test simulation accuracy and the smallest metal channel width ever fabricated using EBL at the University of Toronto is demonstrated at 9nm.
Wind Farm Layout Optimization Using Approximate Inference in Graphical Models
Keywords: approximate inference
probabilistic graphical models
wind farm design

Wind farm layout optimization (WFLO) determines the optimal location of wind turbines within a fixed geographical area to maximize the total power capacity of the wind farm, under stochastic wind conditions and non-linear aerodynamic interferences between turbines. This thesis develops optimization approaches to fast approximate (sub-optimal) turbine layouts to aide engineers make design decisions. Building on previous work in discrete quadratic WFLO models, we recast the program as a probabilistic graphical model incorporating spatial dependencies (i.e., aerodynamic interferences, proximity constraints, and maximum number of turbines) between the variables. Turbine layouts are estimated using message passing inference (BP, TRW-S), which exploit the problem's graph-theoretic structure using decomposition and factorization. We perform an exhaustive computational study comparing TRW-S with branch-and-cut algorithms under varying wind-regime complexity and problem resolutions. We demonstrate the broad applicability of techniques we develop by solving a suite of benchmark quadratic knapsack problems, a general class of problems that arise in many settings.
An Integrated Programmable Wide-range PLL for Switching Synchronization in Isolated DC-DC Converters
Keywords: DAB
Isolated
Photovoltaics
PLL
Programmable
Synchronization

In this thesis, two Phase-Locked-Loop (PLL) based synchronization schemes are introduced and applied to a bi-directional Dual-Active-Bridge (DAB) dc-dc converter with an input voltage up to 80 V switching in the range of 250 kHz to 1 MHz. The two schemes synchronize gating signals across an isolated boundary without the need for an isolator per transistor. The Power Transformer Sensing (PTS) method utilizes the DAB power transformer to indirectly sense switching on the secondary side of the boundary, while the Digital Isolator Sensing (DIS) method utilizes a miniature transformer for synchronization and communication at up to 100 MHz. The PLL is implemented on-chip, and is used to control an external DAB power-stage. This work will lead to lower cost, high-frequency isolated dc-dc converters needed for a wide variety of emerging low power applications where isolator cost is relatively high and there is a demand for the reduction of parts.
Effect of Remote Ischemic Conditioning on Lipopolysaccharide-induced Pulmonary Inflammation
Keywords: Inflammation
leukocytes

Remote ischemic preconditioning (RIPC), an intervention whereby an extremity undergoes brief repeated cycles of ischemia/reperfusion (I/R), has been shown to exert protective effects on distant organ I/R injury. Its potential benefit in organ injury induced by other inflammatory stimuli has not been determined. To test whether RIPC would exert protective effects on LPS-induced pulmonary inflammation, mice were subjected to hindlimb RIPC using a tourniquet prior to intratracheal LPS. RIPC significantly reduced leukocyte recruitment and protein leakage in the lungs at 4 hours after LPS. Lung ICAM-1 mRNA expression was also reduced, whereas TNF-Îą and IL-1Î˛ were upregulated, although these changes were statistically insignificant. However, the protective effect of RIPC was lost by 24 hours after LPS. Moreover, delayed conditioning and dual conditioning before and after LPS administration did not prevent lung inflammation. In conclusion, RIPC provides early protection against LPS-induced pulmonary inflammation in mice, but the effect is not sustained.
Analysis and Design of Single-point Fed Transmission Line Grid 2D Dirac Leaky-wave Antennas
Keywords: 2D Leaky-wave antennas
Broadside/Tilted radiation
Low profile antennas
Pencil beam generation
Single-point feeding
Transmission line grid

Leaky-wave antennas (LWAs) are widely used as single-point fed linear antenna arrays. The extension of LWAs to 2D means that they can be used as single-point fed 2D antenna arrays without requiring a complex feeding network. However, generating a pencil beam from 2D LWAs is not straightforward and due care has to be given to the LWA design. On the other hand, transmission line (TL) grids have demonstrated interesting behaviors, such as negative refractive index and growing of evanescent waves. In this thesis, single-point fed TL-grid 2D LWA designs are proposed that can generate pencil beams at both broadside and tilted angles. The TL-grid is analytically treated in light of the eigenmodes of the TL-grid unit cell, the scattering and impedance parameters and 2D dispersion relation. Additionally, TL-grids are shown to inherently exhibit an open bandgap in the dispersion relation and the TL-grid is perturbed to close this bandgap.
Characterization of Low Melting Temperature, Low-Ag, Bi-containing, Pb-free Solder Alloys
Keywords: Bismuth
Pb-free
Reliability
Solder

Restrictions of lead in solder lead to adoption of SAC305 in consumer products. While high reliability applications use SnPb, supply constraints are driving the adoption of a replacement. SAC305 has reliability concerns related to elevated process temperatures and the formation of Ag3Sn. Reliability performance of three low-Ag, Bi-containing, low melting temperature alloys were compared to SAC305. All three alloys under test performed as well or better for consumer applications. Drop testing and accelerated thermal cycling revealed no differences that would preclude use of these alloys in production. They allow for the use of lower Tg printed wire boards materials, which have been shown reliable. These alloys show promise for high reliability applications. In accelerated thermal cycling, all alloys outperformed the circuit boards. Bi precipitation resulted in less degradation to the bulk microstructure. Bi did not impact the IMC formation or growth, a small amount of Ag mitigated growth of Cu3Sn.
Elementary School Teachers' Attitudes Towards Teaching Mathematics and their Professional Learning Goals
Keywords: Elementary Teachers
Professional Development
Professional Learning Goals
Teacher Beliefs
Teacher Goals
Teaching Mathematics

This study examined how elementary teachers identified and set specific goals to improve their mathematics teaching using the framework of the Ten Dimensions of Mathematics Education (McDougall, 2004). This qualitative study investigates the beliefs and attitudes of four Grade 6 teachers using data collected from interviews and surveys. Based on the evidence found in this study, a relationship exists between teachers’ beliefs and attitudes towards teaching mathematics, their professional learning goals, their instructional practices and student achievement. There were three major findings: (1) teachers’ goals were linked to their weakest dimension and were student centered; (2) teachers’ beliefs on constructing knowledge are not aligned with current mathematics education thinking; and (3) professional development, collaboration, and parental involvement also influenced teachers’ goal setting process. Suggestions for teacher professional learning sessions are discussed, including additions to the teacher change model (Ross Bruce, 2007).