FGS - Electronic Theses and Practica
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This collection contains University of Manitoba electronic theses and practica.
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- ItemOpen AccessDesign and development of a multimodal nonlinear optical microscope for applications in biosciences(2024-12-16) Montero Collado, Vladimir; Sherif, Sherif (Electrical and Computer Engineering); Lin, Francis (Physics and Astronomy); Major, ArkadyNonlinear optical microscopy is an expanding field in the area of optical microscopy applied to biosciences. Methods such as Two-Photon Excited Fluorescence (2PEF or TPEF), Second Harmonic Generation (SHG), Third Harmonic Generation (THG), and Coherent Anti-Stokes Raman Scattering (CARS) constitute an improvement over classical (single-photon) fluorescence microscopy. With them, the need for the use of exogenous labelling agents disappears together with issues such as phototoxicity and photobleaching. These techniques can provide detailed structural images and chemical information from unstained samples. The laser wavelengths used in these methods penetrate deeper into the biological tissues and allow us to obtain images with sub-micron lateral and axial resolution. In the present work, a multimodal nonlinear optical microscope was designed and developed. In the instrument, the following nonlinear methods were implemented: 2PEF, SHG, THG with CARS being added in the near future. A compact, reliable, and cost-efficient Yb:KGW laser was used as a light source. The low energy (12 nJ) per pulse decreases the amount of damage to the surrounding sample areas. The ultrashort laser pulses provide us with a broad spectrum that makes it easier to find lines that coincide with the absorption spectra of different biological materials. The software for controlling the instrument was also developed in two versions (single-tile and multi-tile). The multi-tile version allows the scanning of larger sample areas by joining several tiles. Finally, conditions were created for future implementation of CARS using the Yb:KGW radiation to provide the Stokes beam and a Photonic Crystal Fiber to generate the pump beam.
- ItemOpen AccessDirect numerical simulation of turbulent flow and heat transfer within a wavy-channel(2024-12-19) Opperman, Taylor C.; Tachie, Mark F. (Mechanical Engineering); Jian, Fuji (Biosystems Engineering); Wang, Bing-ChenIn this thesis, the effects of varying amplitude-to-period ratio (A/P=0.15, 0.2 and 0.4) on turbulent flow and heat transfer in a wavy-channel at a fixed nominal Reynolds number Reb,nom=5600 have been studied by means of direct numerical simulation (DNS). The results of these flows are further compared with those of a plane-channel flow at a similar Reynolds number. The impact of the wavy wall on the turbulent transport of momentum and thermal energy has been thoroughly investigated through the analyses of the first- through fourth-order statistical moments of the velocity and temperature fields, joint probability density function (JPDF) of the velocity and temperature fluctuations, budget balance of both the turbulence kinetic energy (TKE) and turbulence scalar energy (TSE) transport equations, swirling strength iso-surfaces, 2-D spatial two-point cross- and auto-correlation coefficients of the velocity and temperature fluctuations, and pre-multiplied energy spectra of the velocity fluctuations. A separation region is observed in the wave troughs, resulting in a mean flow recirculation bubble where the convective heat transfer is greatly impacted. It is also observed that the wavy wall induces a strong shear layer at the wave peak that envelope the recirculation bubble and further enhances the transport of turbulence kinetic and scalar energy between the high-momentum hot outer flow and low-momentum cold near-wall flow. Furthermore, it is interesting to observe that as the wave steepness increases, the characteristic length scales of turbulence structures become increasingly shortened in the streamwise direction while aligning more prominently in the vertical direction. Analysis of key performance parameters such as the Nusselt number and total drag coefficient reveal that the thermohydraulic efficiency decreases as the value of A/P increases.
- ItemOpen AccessIncidence of gasoline taxes in Canada: an event study approach to estimating pass-through(2024-12-11) Vortia, Pooja; Shartaj, Mostafa (Agribusiness and Agricultural Economics); Mann, Janelle (Economics); Lawley, ChadThis study investigates the city-level pass-through rates of provincial and carbon tax changes on wholesale and retail gasoline prices in Canada from 1998 to 2024. Focusing on tax increases and decreases, the analysis measures pass-through rates to explore the impact of tax policies on gasoline prices across Canada. This study also analyses the tax incidence of medium/small cities and large cities separately to examine regional pass-through rates. Data is collected from Kent Marketing Ltd and Statistics Canada to create panel datasets for an event-based difference-in-difference model. Event plots show an immediate response in retail gasoline prices following tax changes; however, retail prices begin to adjust even before the implementation of tax policies. The estimated pass-through rate of gasoline tax increases on retail prices is 100% in the 9-week window and 88% in the 17-week window. For tax decreases, the pass-through rates are even higher, at 120% in the 9-week window and 140% in the 17-week window. The analysis also reveals the significant impact of tax changes on retail prices in medium/small cities and large cities. However, the study finds that the impact of gasoline tax changes on wholesale prices is statistically insignificant for both the 9-week and 17-week windows. Additionally, results from the 9-week window gasoline tax analysis without fixed effects and covariates are insignificant, underscoring the importance of accounting for these factors. In conclusion, the findings of this study emphasize the crucial role of provincial and carbon tax policies in shaping retail gasoline prices, while highlighting the limited impact on wholesale prices in Canada.
- ItemOpen AccessLinear and nonlinear characterization of particulate composites using microstructure-free finite element modeling(2024-12-17) Oli, Sebak; Liang, Xihui (Mechanical Engineering); Zhu, Guo-zhen (Mechanical Engineering); Luo, YunhuaParticulate reinforced composite materials, particularly metal-matrix based alloys, represent a group of materials widely used across various industrial and engineering sectors due to their unique advantages, such as isotropic properties and ease of manufacturing. The effective properties of particulate composites are primarily determined by the properties and volume fractions of the constituent phases. Effective properties refer to the macroscopic properties of composites resulting from the interaction of their phases. Characterizing these effective properties is a crucial step in designing high-performance particulate composites. However, existing methods face fundamental limitations, especially in the nonlinear characterization regime. In this thesis, the recently developed microstructure-free finite element modeling (MF-FEM) approach is extended to characterize the linear properties of three-phase particulate composites and the nonlinear properties of two-phase particulate composites. The main advantages of MF-FEM include: cost-effectiveness compared to experimental methods; greater reliability than analytical models; and circumventing the complexity of modeling intricate microstructures required in traditional finite element methods. MF-FEM predictions of effective properties closely align with experimental results, particularly in cases where phase materials exhibit significantly mismatched properties. This study demonstrates that MF-FEM is a reliable and cost-effective tool for designing particulate composites.
- ItemOpen AccessThe agential torrent: an a/r/tographic exploration of face-to-face classroom encounters(2024-12-18) Clark, Tony; Irwin, Rita (Curriculum and Pedagogy, University of British Columbia); De Oliveira Jayme, Bruno (Curriculum, Teaching and Learning); Black, JoannaAfter two years (2019-2021) of frustrating online crisis teaching in response to COVID-19, I came to a new appreciation of what I had previously taken for granted in my classroom teaching experiences. Provoked by a tangible feeling of loss, this thesis investigates the abiding question of how to better understand and describe the experience of bodies participating in an educational setting. Using a/r/tography and self-study research methodologies, and by applying the onto-epistemology of agential realism and an embodied cognition framework, this paper and graphic novel examines the agential and embodied nature of face-to-face classroom interactions (both human and non-human). The paper attempts to describe the intensely interconnected, multifaceted, and overwhelmingly complicated relations (involving actants) continually forming and reforming - a torrent of agency. Three a/r/tographic renderings are employed in the graphic novel: (1) intra-actions between agential classroom bodies are comprised of waves; (2) the nature of these multi-layered and interweaving intra-actions is entangled; and (3) the ongoing and discursive nature of these intra-actions results in emergence. This resplendent maelstrom of classroom phenomena is contrasted with the diminutive and capitalistic neoliberal educational narrative. The research was provoked by the imposed juxtaposition of these two paradigms during the onset of COVID-19 and subsequent moves to sustain society and the education system through online crisis learning. The paper concludes with discussion questions as prompted in the graphic novel to further the reader’s collaborative study of face-to-face learning.