VictorJuiz/thesis huggingface dataset:
Vortex-induced Vibration and Forced Oscillation Motion of a Circular Cylinder Fitted with a Single Spanwise Tripwire

This experimental study consisted of two main parts. The first part investigated the control induced by a spanwise tripwire on a circular cylinder undergoing one-degree-of-freedom vortex-induced vibration (VIV). The cylinder vibrates in the cross-stream direction as a result of the fluid forcing in a recirculating water tunnel. Changing mass and damping ratios in the test rig allowed the investigation at different VIV response branches. The tripwire diameter was 6.25% of the cylinder diameter. Experimental research was conducted by attaching the large-scale tripwire along the span of the cylinder at various angular positions ranging from 0° to 180° (with respect to the most upstream point of the cylinder). Along with measuring the trajectory of the cylinder motion, the instantaneous velocity field in the near wake of the cylinder was obtained simultaneously at a fixed Reynolds number of 10,000 (based on the cylinder diameter) using a Particle Image Velocimetry (PIV) system. Various vortex-formation modes induced by the tripwire were observed. It was shown that the oscillation pattern, frequency, and amplitude of the cylinder can be altered significantly depending on the angular position of the tripwire and the VIV response branch. For specific tripwire positions, increases of up to 52 times and decreases of up to 98% were identified in the oscillation amplitude of the tripped cylinder compared to the amplitude of the clean cylinder.The second part of the study investigated the effects of the tripwire on the flow structure behind a circular cylinder forced to oscillate harmonically at prescribed amplitudes and frequencies in the cross-stream direction. Oscillation amplitudes are 0.05, 0.3 and 0.6 times the cylinder diameter, and oscillation frequencies are 0.61, 0.8, and 1 times the vortex shedding frequency of the stationary clean cylinder counterpart. For a fixed oscillation amplitude and frequency, the tripwire can either induce intermittent switching between various vortex shedding modes or cause a wake mode to be dominant during the entire observed oscillation motion by altering the vortex shedding mechanism. The wake of the tripped cylinder undergoing the lowest amplitude forced oscillation motion showed resemblance to the wake of the stationary tripped cylinder.

Keywords: Cylindrical structure
Flow–structure interactions
Forced oscillation motion
Tripwire
Vortex-induced vibration
Advisor: Ekmekci, Alis
Design and Applications of Printed-circuit-board Huygens' Metasurfaces

As applications involving electromagnetic waves as carriers of energy and information have become common in society, the ability to tailor and control electromagnetic fields has become proportionally more demanding. In recent years, with the emergence of the Huygens' metasurface, applications and functionalities previously thought to be unachievable have been demonstrated. Due to their intimate and complete control over incident electromagnetic waves, Huygens' metasurfaces theoretically allow the arbitrary manipulation of the involved electromagnetic fields. In this thesis, demonstrations of designs and applications of these remarkable devices are presented. Applications including beam collimation, angle doubling, and perfect refraction are investigated. Additionally, realization of printed-circuit-board prototypes are detailed with designs utilizing stacked-layer and wire-loop structures. Throughout the different applications, both transverse-electric and transverse-magnetic designs are shown. Furthermore, to demonstrate the versatility of Huygens' metasurfaces, the operational frequency of the prototypes ranges from K-band to V-band. Details regarding theoretical and fabrication trade-offs are also considered for all presented designs. Theoretical aspects such as zero loss, passivity, reciprocity, impedance equalization, and local power conservation are studied in detail. Moreover, design and fabrication considerations are also investigated thoroughly. By analysing the designs via fullwave simulation tools and experimental measurements, the functionalities of the presented metasurfaces are validated. Additionally, the frequency responses of the designs were also presented and discussed. Lastly, future opportunities and design considerations were also outlined. Although the designs presented in this thesis only serve as early examples of Huygens' metasurfaces, the achieved results demonstrate the capability and versatility of these devices for achieving various applications. Due to these remarkable abilities, the Huygens' metasurface will undoubtedly become an indispensable tool for solving increasingly challenging electromagnetic problems in the near future.

Keywords: Antenna
Electromagnetic
Metasurface
Refraction
RF
Wave
Advisor: Eleftheriades, George V
In-between Places: A Narrative, Arts-informed Exploration of the Knowledge, Values, and Beliefs of English Language Instructors

This research study, written as a narrative, arts-informed multiple case study, provides a model of reflective practice for TESOL professionals. Based on a foundation of holistic education, this study is an in-depth exploration of the teacher-self, centred on the hearts, minds, and behaviours of four English as an Additional Language (EAL) instructors of adults at mid-career. The central question of this study was, In what ways do English as an Additional Language (EAL) instructors of adult learners describe transformations in their knowledge, values, and beliefs about teaching and learning over the course of time? Engaged in an 8-month long Professional Learning Community (PLC) using Kolb’s Experiential Learning Cycle as the framework for reflection and growth, participants completed creative and reflective writing tasks and participated in group discussions in order to investigate their knowledge, values, and beliefs and how these shaped their perspectives, impacted their decision-making, and influenced their behaviours both inside and outside the classroom. Through actively investigating and constructing meaning from their lived experiences, participants imagined and created new ways of being and teaching. Participants were interviewed 4 years and 13 years after their participation in the PLC in order to identify the most significant changes in their knowledge, values, and beliefs. Findings showed that peer-based, continued professional development (CPD) involving writing and dialogic reflection are powerful methods and means for mid- to late- career EAL instructors to uncover hidden assumptions, develop alternate perspectives on experiences, build upon their diverse knowledge, and develop and share their expertise. Findings also showed an impact on the participants’ knowledge, values, and beliefs as they each progressed through various life stages and career transitions. While certain values remained the same over time, others changed as a result of the participants’ personal and professional growth. Implications of this study address research and practice at three levels. First, at the individual level, focusing on educators and students, second, at the level of professional development practices, and third, at the policy level related to professional learning and development within the community college context.

Keywords: arts-informed
mid-career EAL instructors
multiple case study
narrative
professional development
professional learning community
Advisor: Gagne, Antoinetté
Quantifying Sources of Nitrogen Oxides in Remote Environments: From Biosphere-Atmosphere Exchange to Renoxification

Nitrogen oxides (NOx = NO + NO2) are an important constituent to the global atmosphere due to their strong connection to ozone (O3) and hydroxyl radical (OH). Anthropogenic NOx emissions have been regulated worldwide, leading to a decreasing trend over the past 15 years in North America and Europe, which makes biogenic sources and recycling pathways more important, especially in remote regions that are less influenced by human activities.A two-channel chemiluminescence instrument with high precision and time resolution was used to quantify NOx in the field and the laboratory. In the field, direct measurements of biosphere-atmosphere exchange of NOx were made above a temperate broadleaf forest using the eddy covariance flux method. Near-zero NOx fluxes suggest that the soil NO emissions barely escape the canopy, and an air mass back trajectory analysis indicates that the morning NOx maximum is mainly associated with long-range transport of pollution. Flux divergence observed at this site is a consequence of fast chemical processes and different light intensity above and below the canopy. In the laboratory, NOx and other products from the photolysis of suspended inorganic particulate nitrate were measured in chamber experiments as a function of wavelength, relative humidity, and presence of photosensitizers. The photolysis rate constants of particulate nitrate measured are within an order of magnitude of that of gas-phase HNO3. This finding is in contrast with several studies showing a larger enhancement factor (EF) of renoxification of particle nitrate relative to HNO3. Different values of EF were applied to monitoring data from Environment and Climate Change Canada, to estimate NOx production from the photolysis of particulate nitrate and HNO3. Results were then compared with soil NOx emissions from a global model, showing that renoxification could potentially compete with biogenic NOx in remote environments and needs further investigation.

Advisor: Murphy, Jennifer
Long-term Analysis of Toronto-Area Atmospheric Composition

This thesis examines total columns of C2H2, C2H6, CH4, CH3OH, CO, H2CO, HCl, HCN, HCOOH, HF, HNO3, N2O, NH3, and O3 measured using Fourier transform infrared (FTIR) spectroscopy to study Toronto-area atmospheric composition. The thesis has three scientific objectives: to quantify trends in the time series of trace gas concentrations, to determine how emissions from biomass burning events affect air quality over Toronto and whether observations in Toronto can be used to quantify wildfire emissions, and to examine the spatial representativeness and temporal variability of the FTIR NH3 columns over Toronto.Trends and enhancement events were determined by fitting trended Fourier series to the total columns, and bootstrapping was used to identify the statistical significance. Trends from 2002 to 2019 were examined, and the GEOS-Chem chemical transport model was used to identify major sources of CO and CH4 over Toronto, which were CH4 oxidation and wetland emissions, respectively. Transport of wildfire plumes over the site results in enhanced columns of biomass burning species. Several simultaneous enhancements of CO, HCN, and C2H6 were observed, and the measured columns were used to derive emission ratios and emission factors for HCN and C2H6 for fire events in 2012, 2015, and 2017. For the 2015 and 2017 events, simultaneous enhancements of HCOOH and CH3OH were observed, and their emission ratios and emission factors were also examined. Atmospheric NH3 is a pollutant, and a major source of fine particulate matter. In this study, three NH3 datasets were used: TAO FTIR total columns, three years of surface in situ measurements, and ten years of total column measurements from the Infrared Atmospheric Sounding Interferometer (IASI). The datasets were used to quantify NH3 temporal variability over Toronto, Canada. All three time series showed positive trends in NH3 over Toronto: 3.56 ± 0.85 %/year from 2002 to 2019 in the FTIR columns, 8.88 ± 5.08 %/year from 2013 to 2017 in the surface in situ data, and 8.38 ± 1.54 %/year from 2008 to 2018 in the IASI columns. The multiscale datasets were also compared to assess the representativeness of the FTIR measurements.

Keywords: Atmosphere
FTIR
TAO
Trends
Advisor: Strong, Kimberly
“Play your broken music to my broken song?” Contemporary Implications of Performing Schubert Lieder in English Translation

This study uses the songs of Franz Schubert as a foundational example to consider the contemporary implications of performing Lieder in English translation. Over the last 150 years such translations have been written, published, performed, and rationalized in a variety of ways. However, their “validity” is now broadly dismissed in both pedagogical and performance contexts. This begs the question: how did performance in the original language become an essential aspect of Lieder performance across the English-speaking world? In probing this question, my objective is to reimagine the possible role of such a translational approach in mediating, or even repairing something that is currently “broken” in Anglophone encounters with Lieder. To fulfil this objective, an initial discussion of ontologies of Lieder attempts to examine singing translations alongside other approaches that extend, transform or otherwise challenge the traditional boundaries of the genre, and the ways that these approaches aim to satisfy less dominant notions of “authenticity”. This is followed by an examination of the historical and contemporary debate and attempts to establish adequate translational methodologies amongst a range of aesthetic, nationalistic, and theoretical issues. In addition to this engagement with public documents (including translations, paratextual materials, articles and reviews), I have solicited the views of a range of contemporary stakeholders on the implications of the practice and assembled a collection of thirty-three distinct singing translations of “Der Leiermann”, the final song of Schubert’s 1828 song cycle, Winterreise (D911, op. 89). This collection serves to demonstrate a plurality of translational approaches, the inevitable subjectivity of the translational role, the impossibility of a “definitive” translation, and new avenues of expression engendered by that lack of definition. In considering “the English Lied”, this study has two aims: to provide insight into the complicated relationship we have with language and meaning in this repertoire, and to prompt a reconsideration of singing in translation: one that does not limit itself to concepts of fidelity and failure, but rather opens itself to the creative possibilities of interacting with the repertoire in this way.

Keywords: English
Leiermann
Lieder
Schubert
Singable
Translation
Advisor: Packman, Jeff
Evangelicals, the Liberal State, and Canada’s Family Values Debates: The Struggle to Shape Selves

One of the most pervasive challenges for liberal democracies is the ongoing tension between religious conservatives and the liberal state. Using as my central case study, the highly-charged debates over “family values” in Canada circa 1985-2015, I argue that despite claims that liberal democracy enables religious freedom, its values and extensive reach prove challenging to conservative religiosity. Heightening the stakes is that the rival worldviews I examine – liberalism and evangelicalism – are ambitious, struggling not merely over matters such as same-sex weddings but ultimately for the ability to shape selves. My research focuses on certain central nodes of family values politics, namely three conservative evangelical lobbies – the Evangelical Fellowship of Canada, Focus on the Family Canada, and the Canada Family Action Coalition – as they enter political debates, confront state bodies and legislation, and try to gain a hearing in the country where liberal pluralism has achieved a cultural power perhaps unmatched anywhere else. This study examines the lobbies’ discursive output in order to: trace the ideological drivers of evangelicals’ family values focus; question liberal democratic theory’s emphasis on reason and freedom at the expense of affect and compulsion; and contribute to a rethinking of a central question in secularization theory, by suggesting that persistent disputes over American versus European exceptionalism overlook the most important factor – that Western societies’ ability to resist secularization has rested chiefly on the relative strength of its evangelical community. In short, America’s relative religiosity has depended primarily on the strongly held commitments that foster evangelical exceptionalism.

Keywords: Affect Theory
Canada
Evangelicalism
Liberalism
Politics
Secularism
Advisor: Coleman, Simon
Bryant, Joseph
Metal 2-Adamantyl Complexes: Synthesis and Characterization

This thesis describes the synthesis and characterization of several new 2-adamantyl metal complexes via transmetallation. Chapter 2 – Synthesis of 2-Adamantyl Anions for use in Transmetallation outlines new procedures for generation of 2-adamantyl transmetallating agents, including [(2-Ad)2Zn], [(2-Ad)MgBr], and [(2-Ad)2Mg(THF)2]. Chapter 3 – Synthesis of 2-Adamantyl Metal Complexes is focused on the utility of the newly developed transmetallating agents. The synthesis of several complexes, including those of gold, iridium, platinum, and tantalum using [(2-Ad)ZnBr] (a commercially available precursor), [(2-Ad)2Zn], and [(2-Ad)MgBr] is explored. The efficacy and ease of use of [(2-Ad)2Zn] was instrumental in development of isolable and fully characterizable complexes of both gold 2-adamantyls, and platinum 2-adamantyls. Owing to the well-developed chemistry of platinum alkyls, Chapter 4 – The Chemistry of Platinum(II) 2-Adamantyls focuses on the nature of the 2-adamantyl ligand compared to well-known platinum(II) alkyl complexes of methyl, phenyl, neopentyl, and cyclohexyl. The expansion of synthetic procedures for further modification of platinum(II) 2-adamantyls, as well as assessment of the trans influence of the 2-adamantyl ligand is discussed. Chapter 5 – The Synthesis and Chemistry of Pt(IV) 2-Adamantyls expands on the robust platinum(II) chemistry, allowing for synthesis and characterization of 2-adamantyl platinum(IV) complexes. Future work towards the use of the resulting organometallic species, and applications to C-H activation of the 2-adamantyl γ-CH2 offers a promising pathway towards new adamantyl chemistry. As such, Chapter 6 – Considerations for γ-C-H activation of 2-adamantyl discusses the potential for metal-mediated activation and functionalization of the 2-adamantyl γ-CH2 position, with the goal of generating a facially tri-substituted 2-adamantyl compound. Such a compound is currently inaccessible using organic methods, and only one successful fluorination leading to a facially tri-substituted adamantyl was reported in 2020. Development of 2-adamantyl metal complexes provides promising new developments for both catalysis and organic synthesis.

Keywords: Adamantane
C-H activation
Crystallography
DFT
Organometallics
Advisor: Fekl, Ulrich W
Deep Learning on Graphs: Theory, Models, Algorithms and Applications

Structures or graphs are pervasive in our lives. Although deep learning has achieved tremendous success in many engineering fields, it is still limited in handling various structured data. More importantly, humans have the remarkable ability to learn discrete structures from data to facilitate explainability and generalization, which current deep learning systems can not parallel. In this thesis, I present our work, which revolves around how to improve deep learning for graphs from aspects of theory, models, algorithms, and applications.We first provide a theoretical investigation on graph neural networks (GNNs), an increasingly popular class of deep neural networks that are promising in learning with graphs. We establish PAC-Bayes generalization bounds for common GNNs and show the connection to the results for regular neural networks. In the second part, we look at the limitations of current GNNs and introduce novel models that effectively capture multi-scale dependences in graph convolutions and efficiently propagate messages using asynchronous schedules. Moreover, we study the graph generation problem and introduce a new deep auto-regressive GNN that can generate high-quality graphs in a scalable and fast manner. In the third part, we revisit an implicit gradient based learning algorithm and propose new variants that are effective in training message-passing GNNs. At last, we demonstrate our efforts of customizing GNNs to achieve impressive performances in many practical application domains, including computer vision, reinforcement learning, and probabilistic inference. I summarize the thesis and discuss promising future directions in the final chapter.

Advisor: Zemel, Richard
Urtasun, Raquel
ENERGY MODELS FOR PRUNING NEURAL NETWORKS

Deep neural networks (DNNs) have achieved significant performance improvement in image classification tasks.A DNN utilizes an enormous number of trainable parameters and non-linear functions to learn a mapping from a set of input images to a set of target classes. However, the increasing number of parameters, called the overparameterization problem, can create major challenges in implementation of these models on resource limited devices and can encourage overfitting of the model. Pruning less important trainable parameters in DNNs is one of the major established methods to defeat the above challenges. Pruning methods are also applicable on small models by design to further reduce their size. This thesis proposes the concept of energy models for pruning convolutional filters and hidden units with corresponding incoming and outgoing connections and bias terms for image classification tasks. Specifically, two energy models, namely EPruning and IPruning, are proposed. The first approach uses the Hamiltonian of a given DNN to form an energy loss minimization problem. The loss function is defined based on the difference between the energy of target class and the closest energy of the competitive classes. The second approach uses entropy of feature maps, Kullback–Leibler (KL) divergence between convolution filters in a layer, and activation level of hidden units to form an Ising energy-based minimization problem for detecting less important and redundant parameters in the network. Despite most pruning methods, which are based on defining a pruning threshold per layer, the proposed methods are data-driven and perform a network-wise pruning of the trainable parameters. We define pruning as searching for a sub-network of a given DNN, which has the lowest energy loss value based on a defined energy loss function. Since this is an NP-hard combinatorial optimization problem, a population-based global optimization framework is proposed to minimize the pruning objective functions. The proposed framework is evaluated on different flavors of DNNs (e.g. ResNets, AlexNet, and SqueezeNet) and datasets (e.g. CIFAR-10, CIFAR-100, and ImageNet) for image classification tasks.

Keywords: Deep learning
Dropout
Energy models
Ising model
Pruning
Advisor: Valaee, Shahrokh