bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural vibrations and internal ballistic modelling of a star-grain solid rocket motor
Authors: Loncaric Sonny
Published: May 2021

A numerical model is developed to solve the governing equations for the structural dynamics and internal ballistics of a solid rocket motor (SRM). An explicit finite element method is used to solve for the structural response, and an explicit finite volume method is used to solve for the internal ballistic flow. Together, these two numerical solutions are coupled to model the nonsteady behaviour of axial combustion instability in sleeved cylindrical- and star-grain SRMs.

The simulation model is used to predict the axial instability in star-grain SRMs. A parametric analysis is made to record the effects of various parameters on the simulation model. These parameters include the numerical dissipation constant, damping ratio and pulsing strength. It is found that both the numerical dissipation constant and damping ratio can, both artificially and physically, affect the finite element structural response of the motor. The pulsing strength affects only the rate at which the do pressure rises as well as how quickly the limiting wave amplitude is reached.

A numerical model is developed to solve the governing equations for the structural dynamics and internal ballistics of a solid rocket motor (SRM). An explicit finite element method is used to solve for the structural response, and an explicit finite volume method is used to solve for the internal ballistic flow. Together, these two numerical solutions are coupled to model the nonsteady behaviour of axial combustion instability in sleeved cylindrical- and star-grain SRMs.The simulation model is used to predict the axial instability in star-grain SRMs. A parametric analysis is made to record the effects of various parameters on the simulation model. These parameters include the numerical dissipation constant, damping ratio and pulsing strength. It is found that both the numerical dissipation constant and damping ratio can, both artificially and physically, affect the finite element structural response of the motor. The pulsing strength affects only the rate at which the do pressure rises as well as how quickly the limiting wave amplitude is reached.The detailed analysis of simulated star-grain SRM axial instability reveals the effect of structural vibrations on burning rate augmentation and wave development in nonsteady operation. The variation in oscillation frequencies about a given grain section periphery, and along the grain with different levels of burnback, influences the means by which the local acceleration drives the combustion and flow behavior. The amount of damping also plays a role in influencing the predicted instability symptoms of the motor.
Microstructural characterization and mechanical properties of spot welded dissimilar advanced high strength steels
Authors: Khan Muhammad Sohaib
Published: May 2021

Increased use of advanced high strength steels (AHSS) in resistance spot welding is necessary for manufacturing safe and affordable vehicles. A significant body of work has been completed to document the resistance spot weldability of AHSS. However, In automotive applications, the dissimilar material combinations are very common In automotive construction. There is no literature regarding the resistance spot welding of dissimilar materials DP600 and HSLA350 steels. The objective of this study was to investigate the weldability and mechanical properties of resistance spot welds between HSLA350 and DP600 steels. The dissimilar material spot weld performance was different than the similar material spot welds in each of the HSLA350 and DP600 steels and exhibited different heat affected zone hardness. The DP600 weld properties played a dominating role on the microstructure and mechanical properties of the dissimilar material spot welds. However, the fatigue performance of the dissimilar welds was similar to that of the HSLA welds. Fatigue tests on the dissimilar materials spot welds showed that at a given stress amplitude the 5.5 mm diameter nugget exhibited higher fatigue strength than the 7. 5 mm diameter nugget.
Examining the representations of social actors in FASD prevention campaigns
Authors: Yandt Riki
Published: May 2021

Through an exploration of public health campaigns targeting the prevention of FASD, I identified and challenged the concepts of mother blame and stigma found within the discursive practices of the medical system. Framed by feminist theory and critical discourse analysis (CDA), I used van Leeuwan’s approach to social actors to name and explore the representations of people depicted within the campaigns. The discussion focuses on how the current discourse on FASD informs the way that people are perceived and explores possible avenues to challenge and shift the way that substance use is discussed in relation to women and pregnancy.
Shaping Toronto: female economy and agency in the corset industry, 1871-1914
Authors: McKnight Alanna M. M.
Published: May 2021

In amplifying the contours of the body, the corset is an historical site that fashions femininity even as it constricts women’s bodies. This study sits at the intersection of three histories: of commodity consumption, of labour, and of embodiment and subjectivity, arguing that women were active participants in the making, selling, purchasing and wearing of corsets in Toronto, a city that has largely been ignored in fashion history. Between 1871 and 1914 many women worked in large urban factories, and in small, independent manufacturing shops. Toronto’s corset manufacturers were instrumental in the urbanization of Canadian industry, and created employment in which women earned a wage. The women who bought their wares were consumers making informed purchases, enacting agency in consumption and aesthetics; by choosing the style or size of a corset, female consumers were able to control to varying degrees, the shape of their bodies. As a staple in the wardrobe of most nineteenth-century women, the corset complicates the study of conspicuous consumption, as it was a garment that was not meant to be seen, but created a highly visible shape, blurring the lines between private and public viewing of the female body. Marxist analysis of the commodity fetish informs this study, and by acknowledging the ways in which the corset became a fetishized object itself, both signaling the shapeliness of femininity while in fact augmenting and diminishing female bodies. This study will address critical theory regarding the gaze and subjectivity, fashion, and modernity, exploring the relationship women had with corsets through media and advertising. A material culture analysis of extant corsets helps understand how corsets were constructed in Toronto, how the women of Toronto wore them, and to what extent they actually shaped their bodies. Ultimately, it is the aim of this dissertation to eschew common misconceptions about the practice of corsetry and showcase the hidden manner in which women produced goods, labour, and their own bodies in the nineteenth century, within the Canadian context.
"Black Men Have to Work Much Harder": An Exploratory Study on the Gendered-Racialized Experiences and HIV Vulnerabilities of Heterosexual Young Black Men
Authors: Bryce Kimberly M.
Published: May 2021

Research literature on the HIV vulnerabilities of heterosexual young Black men tend to focus on individual risky behaviours, without acknowledging the structural conditions that put them at risk. The aim of this study was to explore the gendered and racialized experiences of heterosexual young Black men, their HIV vulnerabilities, and conditions that promote their collective resilience. Using a narrative approach, I conducted two focus groups and five individual interviews (N=15). I also applied the lenses of Critical Race Theory (CRT) and intersectionality to critically analyze the participants’ narratives. The study results showed that social vulnerabilities, produced through anti-Black racism and White hegemonic masculine expectations, shaped the racialized and gendered identities of the participants and increased their HIV vulnerabilities. Participants identified social support, mentorship, access to equitable opportunities and safe space for critical dialogue as conditions that promote their resilience. Thus, effective HIV prevention responses must be underpinned by social justice.
Novel Anti-Islanding Detection Method and Maximum Power Tracking Algorithm for Grid Connected Photovoltaic Systems with Interleaved DC/DC Converters
Authors: Yafaoui Ahmad
Published: May 2021

Photovoltaic (PV) energy, which has proven to be environmentally friendly and sustainable compared to traditional energy sources, has gained widespread attention in recent years. The grid-tied PV energy conversion system has become a preferred choice for renewable power generation since it does not need energy storage devices. In this dissertation, an advanced stateof-the-art PV energy system is developed. This includes a high-efficiency zero-voltage zerocurrent switching DC/DC converter with active voltage clamping for power loss minimization, a multiphase interleaved power conversion system with cascade control for power rating expansion, a modified maximum power point tracking (MPPT) scheme with improved accuracy and dynamic response, a novel active frequency drift anti-islanding detection met hod with grid code compliances, and a laboratory prototype PV energy system for performance evaluation and verification.

Various soft switched DC/DC converters for PV applications are investigated. A new gating scheme for the converter with active voltage clamping that results in zero-voltage and zerocurrent switching (ZVZCS) is proposed. The operating principles of the proposed converter are presented and its performance is investigated.

To increase the power rating of the PV converters, a multi-channel DC/DC converter system, consisting of multiple units of parallel converters and operating in an interleaved mode, is developed. A new cascade control method is proposed, where the PV array voltage is controlled by a master converter and the active current sharing is implemented by the remaining slave converters. The performance of the new control method under varying temperature and irradiance levels are analyzed and verified by simulation in the Matlab/Simulink platform.

Various MPPT algorithms are investigated and their performance with rapid changes in irradiance and temperature are compared. A detailed simulation of the algorithms is carried out, and an experimental setup is developed.

The islanding phenomenon in renewable energy systems is examined, and an improved active anti-islanding detection method that can detect islanding with less total harmonic distortion compared to the conventional methods is proposed. The rms value and the Fourier series coefficients of the current waveform of the proposed method are obtained and used to derive the operational characteristics of the method.
A Simulation Algorithm Capable Of Modelling Spatial Impact Points From The Neutralization Of An Improvised Explosive Device
Authors: Chan Christopher
Published: May 2021

An improvised explosive device (IED) is a bomb constructed from unknown materials, often concealed, such as inside an innocuous container, and deployed in unconventional ways resulting in a potentially deadly weapon. Public safety personnel such as Explosive Disposal Units (EDUs), are trained in the safe handling of explosives and the threats posed by IEDs. One method of neutralizing a suspect IED is to use water fired from a high-powered dispersion weapon
commonly known as a disrupter cannon. Our research proposes an algorithm for developing an IED neutralization simulation that can emulate real-world physical effects of the successful neutralization of an IED without danger to the public or first responders.
This algorithm includes 6 methodologies with the goal of providing EDU with additional information on the potential physical dispersion of the components of an IED and any major points of impact (splatter) and possible actionable intelligence on the pose and direction of a disrupter cannon for a successful neutralization of an IED. We have developed a prototype simulation based on this algorithm and evaluated the simulation with an appropriate real-world disrupter and compared the real-world splatter to our simulation’s splatter.
We argue systems developed with our algorithm may provide relevant information directly from the simulation and can be accurately used to analyze particle dispersion for the purposes of augmenting EDU IED neutralization processes.
Optimization and Modeling of an Emulsion Polymerization Reactor
Authors: Ghadi Narges
Published: May 2021

A mathematical model was developed to simulate emulsion polymerization in batch, semi-batch and continuous reactors for monomers with high water solubility and significant desorption such as vinyl acetate. The effects of operating conditions such as initiator and emulsifier concentration as well as reactor temperature have been studied. The simulation results revealed the sensitivity of polymer properties and monomer conversion to variation of these operating conditions. Furthermore, the impact of monomer soluble impurities on reduction of monomer conversion has been investigated. In order to control polymer molecular weight, application of chain transfer agents such as t-nonyl mercaptan was suggested. Generally, the simulation results fitted well [with] experimental data from the literature. Several optimizing policies were considered to enhance the reaction operation for better product quality. During continuous polymerization, the reactor demonstrates oscillatory behavior throughout the operation. A new reactor train configuration was consistent with the aim of damping the oscillations and producing high-quality latex.
A Nonlinear Model for the Optimal Capacity Placement in Self-Healing ATM Networks Based on Link Restoration Strategy
Authors: Alam ABM B.
Published: May 2021

Network Survivability is a critical issue in telecommunications network due to increasing dependence of the society on communication systems. Fast restoration from a network failure is an important challenge that deserves attention. This thesis addresses an optimal link capacity design problem for survivable asynchronous transfer mode (ATM) network based on the link restoration strategy. Given a projected traffic demands and the network topology, capacity and flow assignment are jointly optimized to yield the optimal capacity placement. The problem is formulated as large-scale nonlinear programming and is solved using a specific type of Lagrange method (so called Separable Augmented Lagrangian Algorithm or SALA for short). Several networks with diverse topological characteristics are used in the experiments to validate our proposed novel model, using capacity installation cost, routing cost, total network cost, used capacity and required CPU time, as performance metrics. Link restoration strategy is compared against global reconfiguration strategy using these performance metrics.
Conquering Media Coverage : The use of battle metaphors in hospital foundation communications and its impact on news coverage
Authors: Hoffman Sara
Published: May 2021

Battle terminology such as “fight,” “conquer,” and “hero” and imagery that compares doctors and patients to superheroes, soldiers and athletes have become increasingly prevalent in hospital foundation communications. The use of these metaphors has been highly controversial. While some audiences have praised foundation campaigns that use this type of messaging for emphasizing the strength of patients and hospital staff, encouraging patient families, and motivating patients to be resilient, others argue that these campaigns marginalize those who are unable to overcome their health conditions, positioning them as failures or losers. While the use of battle metaphors in hospital communications has been a heated topic in online discussion, little is known about the impact of this language on the media coverage and financial support that they generate for hospitals. This paper presents a multimodal discourse analysis of the communications of six hospital foundations in Toronto, Canada followed by a quantitative and sentiment analysis of the media coverage each foundation has received within the last fiscal year. The aim of this paper is to determine if there is a relationship between the use of battle metaphors in hospital foundation communications and the amount and sentiment of media coverage. According to agenda setting theory, media coverage has a palpable impact on public action. Therefore, the findings of this research may assist hospital foundations in developing useful communications practices they can employ to increase media exposure and, consequently, attract more donations to support their institutions.
Worlds apart: Marx, Marcuse and creative engagement
Authors: van der Post Rebecca
Published: May 2021

Marx’s early account of socialism as the simultaneous liberation of mankind and nature holds creativity to be mankind’s defining and trans-historical characteristic and the locus of human freedom. Yet, as I argue, Marx’s creativity is predicated upon subject-object relations of domination that engender a pathological relationship between humans and
nature, thereby militating against true freedom. This paper will explore Marcuse’s attempt to rehabilitate Marx’s account and will find that Marcuse fails to resolve the crucial tension between subject and object, while his model of freedom contains the possibility for an escalation in the very violations of nature that his account seeks to overcome. Finally, I argue that creative processes and creative engagement suggest a way to resolve the tension in Marx’s account of human nature, while offering us a vantage point from which to critique and subvert the brutality of our own historical moment.
Life Cycle Assessment of Municipal Solid Wastes: Development of Wasted Software
Authors: Diaz Rodrigo
Published: May 2021

This thesis introduces WASTED (Waste Analysis Software Tool for Enironmental Decisions). It is a computer-based model that uses life-cycle assessment (LCA) methodology to estimate material flows and environmental impacts of solid waste management. The model consists of a number of separate submodels that describe a typical waste management process. These models are combined to represent a complete waste management system. Based on LCA methodologies, WASTED uses compensatory systems in order to account for the avoided impacts derived from energy recovery and material recycling. In this manner, a comprehensive "cradle-to-grave" analysis of waste management is possible. The purpose of this project is to provide waste managers, environmental researchers and decision makers with a tool that helps them to evaluate waste management plans and to improve the environmental performance of waste management strategies.
Three-dimensional modeling of SiGe by the traveling solvent method in the presence of magnetic field and rotating crucible
Authors: Jaber Tawfiq J
Published: May 2021

A three-dimensional numerical simulation study was carried out for crystal growth of SiGe by the traveling solvent method (TSM). The Effects of magnetic field intensity and sample rotation on the transport structures (fluid flow, heat and mass transfer and concentraion) in the solvent were investigated in detail. The full stead-state Navier-Stokes equations, as well as the energy, mass transport and continuity equations were solved numerically using the finite element method. An external axial magnetic field is applied to suppress convection in the solvent. It was found that the intensity of the flow at the centre of the crucible decreases at a faster rate compared to the flow near the walls when increasing the magnetic field intensity. This behaviour creates a stable and uniform silicon distribution in the horizontal plane near the growth interface. The application of crucible rotation in the presence of the axial magnetic field is an attempt to control the buoyancy induced convection throughtout the solvent region. It was observed that in the application of rotation, there is no significant change to suppress the flow intensity. It was found that the rotating magnetic field (RMF) has a marked effect on the silicon concentration, changing it from convex to nearly flat when the magnetic field intensity increases. An alternative method for removing buoyancy convection from the melt is growing the crystal in a gravity-free environment. The microgravity (10-4g) is numerically situated and compared with the ground base condition.
The impact of window-related thermal bridging on energy use in MURB retrofits using 2-d heat transfer modelling for full window thermal bridge analysis
Authors: Coburn Jessica
Published: May 2021

There is significant in the GTA for GHG emissions reduction through energy retrofit measures of the more than 2000 post-war multi-unit residential buildings. Overcladding is an effective energy reduction strategy; however, it is crucial to properly detail window installation to avoid thermal bridging in a retrofit situation, as there may be excessive heat loss and condensation at this junction. This paper examines the thermal bridging potential at the window-wall interface in an EIFS overcladding retrofit scenario for a typical MURB retrofit. The research used the software THERM to compare influence of three typical window-wall interface on the energy performance of the window and wall. The analysis examined the position of the window within the frame, insulation placement around the window perimeter. It was found that window placement within the wall section and detailing at the opening do significantly affect the wall’s overall thermal performance, determining that design improvement should be considered and quantified in retrofit energy reduction strategies.
Developing human factors metrics and tools to support design and management of production
Authors: Greig Michael
Published: May 2021

This dissertation takes an exploratory look at the role of human factors (HF) metrics within an electronics manufacturing organization by focussing on three objectives: 1) determining company stakeholder views of HF metrics, metrics development and HF application, 2) developing a workstation level HF assessment tool for light assembly work, and 3) creating a tool that reports the level of HF integration and maturity in an organization. Mixed methods were used in an action research framework. Research at the case organization was predominantly qualitative and included field notes, audio recordings, and company documents. Identified gaps between engineering and HF metrics were due to HF metrics focussed more on health and safety measures and activities being completed, gaps in the understanding of HF contributions, and the need for new HF tools to generate reporting measures. Five identified themes affecting HF metrics development included 1) knowledge of engineer processes and of HF principles, 2) connection of metrics to the organization, 3) support of the organization and of
the information to the organization, 4) resource availability and limitations, and 5) communication format of metrics information. Collaborative user-centered development of a workstation efficiency evaluator tool helped determine data of interest and effective communication of output variables for users. Design stage inputs create outputs that include HF and system information. The tool performed well in a comparison to an observation-based analysis and also demonstrated tolerance to input errors on workstation outcomes. The developed Human Factors Integration Tool assesses HF maturity across organizational functions. Face and content validity of the tool were tested in field testing and workshops. Participants communicated a need for the tool and its contents. Industry stakeholders found the consensus-based tool helped to establish the status of HF in the organization, plan projects to further develop HF capabilities, and initiate discussions on HF for performance and well-being. The created tools demonstrated approaches to the development of future HF tools. These dissertation findings illustrate the need for more HF metric work, including developing HF measures that contribute to organization metrics, and that the development of HF measures and processes need HF considerations in their development.
Quantifying air leakage through party walls in Toronto semidetached and row-home dwellings
Authors: Todd Austin
Published: May 2021

This study contributes to the development of quantifying and understanding building air tightness as it relates to Toronto semi-detached and row homes, particularly party walls. While infiltration characteristics of single family detached homes have been widely developed and understood, the isolation of semi-detached and row home single family dwelling units is relatively unexplored. When quantifying air leakage in a building attached to an adjacent dwelling unit, air is drawn
through the exterior envelope as well as the party wall (i.e. shared common wall). The purpose of the proposed testing method, guarded blower door testing, is to isolate air leakage through the party wall from the envelope. Currently the party wall is considered a fire-rated assembly but is not part of the air barrier system. Issues associated with party wall air leakage include spread of fire, indoor air quality, transfer of tobacco smoke between dwellings, and heat loss through the
party to attic detail. Data collected on buildings constructed between 1890 and 1920 (Century buildings) has been compared to the data collected on buildings constructed between 2012 to 2017 (new buildings). Air leakage has been collected on twenty-six of Century semi-detached homes with solid masonry construction and twenty-one new semi-detached/row homes of lightweight wood frame construction. Each unit was tested independently and simultaneously, or “guarded”, with the adjacent unit, to pressure neutralize allowing for quantification of envelope and party wall air leakage. Party wall leakage was found to be similar to leakage through the exterior walls. The leakage accounted for 22% of the total infiltration in Century old buildings and 38% in Modern dwellings.
Personalised ranking with single source implicit information for recommendation tasks a similarity based Monte Carlo Bayesian Personalised Ranking
Authors: Parisa Lak
Published: May 2021

Background: A recommender algorithm’s main goal is to learn user preferences from the user-system interactions and provide a list of relevant items to the user. In information retrieval literature this problem is formulated as learning to rank
(LtR) problem. Bayesian Personalized Ranking (BPR) [1] is one of the popular LtR approaches based on pair-wise comparison using single source implicit information.
Aim: In this work, we aim to design a recommender system algorithm that generates accurate recommendations. The system should only use a single source implicit user preference information. This is possible through a good approximation of the posterior probability in BPR optimization function.
Method: We proposed a Similarity based Monte Carlo approximate solution for the posterior probability in BPR. We used four datasets from different recommendation application domains to evaluate the performance of our proposed algorithm.
The input data was pre-processed to match with the requirements of the algorithm.
Result: The result of the analysis shows a significant improvement in terms of mean average precision (MAP) for our proposed algorithm compared with the BPR and another alternative extension to BPR.
Conclusion: We conclude that the proposed approximate solution is successful in providing the most informative samples to approximate BPR posterior probability. This is confirmed by the significant improvement of the accuracy of the provided ranked list of items for the users.
i
Space, place, and perceived illegality: the unsanctioned Parkdale Overdose Prevention Site
Authors: Dupuis Erika
Published: May 2021

In August 2018 the Ontario provincial government ordered the halt of several overdose prevention sites across the province. This paper will focus on an unsanctioned site that opened out of response to resist said closures. This study aims to explore how front-line volunteers navigated opening, maintaining, and closing an unsanctioned overdose prevention site amidst a neoliberal government, and whether it had any impact on service provision. The writer interviewed volunteers who frequently worked at the unsanctioned site, discussing their community, activism, and the ongoing efforts to support people who use drugs. The findings of this research suggest that the perception of illegality had impacts on funding, burnout, and community mobilization.

Keywords: governmentality, harm reduction, people who use drugs, unsanctioned overdose prevention sites
Adaptive embedded technologies: hardware acceleration
Authors: Meghdies-Vardeh Ryan
Published: May 2021

This thesis establishes the benefits of multi-architecture systems by using reconfigurable modules in conjunction with a case integration strategy to improve system performance. The modules and strategies discussed in this thesis provide
opportunities to the improve system performance of processing units designed for the consumer market.
The primary objective for this work is to improve the performance of consumer processors using programmable logic, while ensuring the changes are abstracted from operating systems and software applications. This thesis accomplishes this using specified integration strategies, protocols and through optimization of device drivers.
ACQuISITION PROPOSAL FOR CONTEMPORARY BRAZILIAN PHOTOGRAPHS FOR THE GEORGE EAST.MAN HOUSE COLLECTION
Authors: Fernandes Marilia Palhares
Published: May 2021

The present Professional Practice Project is intended as an essay on Brazilian photography. From its history to the naming of selected contemporary artists, this proposal is an overview of photography in Brazil. This paper aims to be a tool for those proposing the acquisition of something unknown to an institution such as George Eastman House, and to prove that it is important to look for images beyond the range of familiar knowledge.
This essay includes an acquisition proposal, with a short biography on each artist included, as well as a section on the history of photography in Brazil. There is also a segment on the acquisitions policies of the institution for which this proposal has been written, with the story of how the major collections within it came to be there.
Substrate Dependent Regulation of the Human Equilibrative Nucleoside Transporter 1 (hENT1) in HEK293 Cells
Authors: Zafar Maliha
Published: May 2021

Nucleosides and nucleoside analog drugs enter cells through nucleoside transporters, such as the human equilibrative nucleoside transporter 1 (hENT1). The regulation of nucleoside transporters is poorly understood. In this study, through fluorescence-activated cell sorting (FACS) analyses, confocal microscopy and radio-ligand binding assays, I show a decrease in hENT1 abundance at the plasma membrane (PM) in HEK cells treated in the presence of a bolus amount of cytidine (40μM) for 6 hours. Kinetic and transport assays indicate that the remaining hENT1 population at the PM has a higher Vmax and Km but there is no change in overall substrate uptake compared to untreated cells. I also show that cytidine pre-treatment leads to an increased cytotoxicity from gemcitabine (a nucleoside analog drug). These are the first data that show direct substrate dependent regulation of a nucleoside transporter by a mechanism that may involve increased recycling/internalization of the transporter.
Three Dimensional Effect of Axial Magnetic Field to Suppress Convection in the Solvent of Ge0.98Si0.02 Grown By the Traveling Solvent Method
Authors: Abidi Leily
Published: May 2021

A three dimensional numerical simulation of the effect of an axial magnetic field on the fluid flow, heat and mass transfer within the solvent of GE0.98Si0.02 grown by the travelling solvent method is presented. The full steady state Navier-Stokes equations, as well as the energy, continuity and the mass transport equations, were solved numerically using the finite element technique. It is found that a strong convective flow exists in the solvent, which is known to be undesirable to achieve a uniform crystal. An external axial magnetic field is applied to suppress this convection. By increasing the magnetic induction, it is observed that the intensity of the flow at the centre of the crucible reduces at a faster rate than near the wall. This phenomenon creates a stable and flat growth interface and the silicon distribution in the horizontal plane becomes relatively homocentric. The maximum velocity is found to obey a power law with respect to the Hartmann number Umax Ha⁻⁷/⁴
Modeling of Bimolecular Nitroxide Mediated Radical Polymerization of Styrene in Batch Reactor and Steady State Analysis of CSTR Reactor
Authors: Matti Basma
Published: May 2021

Controlled radical polymerization (CRP) is a rapidly developing area in polymer science. Its versatility and ability to produce novel polymer structures are the main reasons which attract both academic and industrial interests. In particular, Nitroxide mediated Radical Polymerization (NMRP) is currently one of the three popular approaches in CRP. Polymeric materials synthesized by NMRP can be utilized for coatings, adhesives, lubricants, gels, thermoplastic and also for biomedical applications.

Open literature shows an academic controversy over the kinetic mechanisms of NMRP and also over the kinetic reaction rate parameters. In this study, a kinetic mechanism describing the bimolecular NMRP was thoroughly discussed, reviewed and improved. In fact, two side reactions have been added to the most updated NMRP reaction scheme. Therefore, a kinetic model for a NMRP polymer reactor operating in batch and CSTR modes was developed based on a detailed reaction mechanism for thermal polymerization of styrene and also for bimolecular NMRP of styrene using benzoyl peroxide (BPO) as initiator and 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) as a radical controller. The kinetic model, consisting of a set of ordinary differential equations, was numerically integrated and validated with a set of experimental data obtained at temperature 120°C and [TEMPO]/[BPO] molar ratio 1.1. This model validation was done by means of a parameter estimation scheme to determine the "best" kinetic parameters. The model predictions were compared with data at 120 and 130°C for [TEMPO]/[BPO] molar ratios of 0.9, 1.1, 1.2, and 1.3. A good to very good agreement was obtained between the prediction and data.

The non-linear behavior of the CSTR polymerization reactor was also analyzed using Matlab continuation program Matcont package. Typical hysteresis behavior, input and output multiplicities, as well as disjoint bifurcations were determined for this reactor. The bifurcation parameters selected are the coolant flow rate, feed stream temperature, residence time, initiator feed stream concentration and controller feed stream concentration. Bifurcation analyses reveal the stable and unstable operating regions of the reaction. Thus, the results obtained can be employed as a guide to develop a process control strategy for a better and safer operation of the NMRP polymerization reactors. Finally, a steady state optimization for the CSTR reactor was carried out in order to identify the optimal operating conditions of the NMRP process.
Fiber loop ring-down spectroscopy with a long-period grating cavity
Authors: Pu Xiaojun (Sean)
Published: May 2021

Cavity Ring-down spectroscopy is an absorption detection technique that makes the[sic]use of an optical cavity to realize a long effective optical path length through a sample and to render the measurement independent of intensity. These two features give the ring-down spectroscopy many advantages over traditional absorption techniques and allow it to measure chemicals present in trace amount.

This thesis presents my study of fiber loop ring-down spectroscopy with a long-period grating (LPG) cavity as the sensing section. There are several advantages in this design: 1) It provides a relatively larger sensing area for the evanescent wave to interact with the environment when compared with a fiber taper and a D-shaped fiber; 2) The LPG cavity has a much lower insertion loss than the micro-cell; and 3) The tensile strength of the fiber is well preserved.

Many issues such as the LPG mode order, LPG cavity loss, sample cell design, ring-down pulse detection and analysis have been studied. As an example, the technique was applied to measure the spectral absorption of 1-octyne in decane solution and a detection limit of 0.62% 1-octyne was determined with the exist[ing] experimental setup, which is a fact or 2 better than the result using fiber taper.
Spatial and temporal patterns of biophysical variables and their influence on CO2 flux in a high arctic wetland
Authors: Luce Sarah
Published: May 2021

Arctic wetlands have been globally important carbon reservoirs throughout the past but climate change is threatening to shift their status to carbon sources. Increasing Arctic temperatures are depleting perennial snowpacks these wetlands depend upon as their hydrological inputs which is altering their environmental conditions and carbon cycles. The objective of this study is to investigate how the physical conditions of Arctic wetlands will be altered by climate change and what influence these changes will have on CO2 exchange. High spatial and temporal resolution biophysical data from a high Arctic wetland, collected over the growing season of 2015, was used for this analysis. The results from this study indicate that the wetland is at risk of thawing and drying out under a warmer climate regime. CO2 emissions were found to increase most significantly with increased air temperatures, while CO2 uptake increased with increases in solar radiation and soil moisture. Combined, these results suggest that CO2 production in the soil will increase while CO2 uptake will decrease in Arctic wetlands as climate change continues.
Older patient-physician communication: an examination of the tensions of the patient-centred model within a biotechnological context.
Authors: Jenkins Catherine Anne May
Published: May 2021

Drawing on existing theoretical work, as well as field research, this dissertation examines the impact of medical imaging technologies on communication between physicians and older patients when diagnostics often privilege disembodied data over the patient voice. Current diagnostic trends are contextualized within the history of medicine, from Ancient Greece to the present, including the development of imaging. Since the 1970s, advanced medical imaging technologies (e.g., ultrasound, computed tomography, magnetic resonance imaging) have become the diagnostic norm in Western medicine. The rapidity of this shift, which renders the human body as flattened data, can outstrip considerations of the implications of applying such technologies to living patients.

Focusing on older patients, who may be less technologically savvy than younger patients or medical professionals, the field research begins with semi-structured interviews of patients over age sixty-five, exploring their encounters with medical imaging equipment and professionals. This data is interrogated qualitatively using Foucauldian discourse analysis drawing on Andrea Doucet’s model of slow scholarship, and informed by Arthur Frank’s notion of letting stories breathe; themes were allowed to surface from the patients’ narratives, rather than imposed by the researcher. Information emerging from the data considers patients’ emotions, unexpected physical sensations, communicative strategies and rationalizations, as well as Foucauldian allusions to power. Observational research was also conducted during encounters between physicians and simulated patients in the presence of medical images; these encounters were followed by reflective exit interviews.

Research indicates that although physicians are increasingly trained in patient-centred communication, it is not always optimally practised. Physicians are sometimes more comfortable with the medical discourse of disease than with the emotional, metaphoric language of the patient’s illness experience. Since the development of modern Western medicine in Europe of the late 1700s, physicians have been trained to seek pathology, with the increasing aid of medical technologies, rather than listening to their patients. For older patients, who may experience
multiple co-morbidities, the lack of communication around advanced medical technologies can increase their sense of vulnerability and anxiety. The dissertation concludes with recommendations for both patients and practitioners to improve communication in the medical
context.
Racism, the environment, and persecution : environmental refugees in Tuvalu
Authors: Mann Natasha
Published: May 2021

This paper explores the concept of environmental refugees through a literature review and discourse analysis of media coverage on Tuvalu. Tuvalu is predicted to be the first nation lost to sea level rise and its government has been active in attempting to secure a place of asylum for its citizens. Although the term 'environmental refugee' is not an official one, it is widely used. Therefore, a case study is used to illustrate how environmental refugees are constructed in the public eye. Using political economy and political ecology approach, the power dynamics that lead to disproportionate environmental destruction in poor, racialized areas as well as unequal access to migration are questioned. Looking at two major newspapers each from Canada, the US, Australia, and New Zealand, and one from Tuvalu, the discourse surrounding environmental refugees reveals how the term is constructed and used for varying agendas, from environmentalism to racial exclusion.
An Assessment of Municipal Capacity for Human-Wildlife Conflict Management in Selected Urban Areas of Southern Ontario
Authors: Kalt Stephanie Anee
Published: May 2021

Recently many Canadian municipalities have begun to experiment with urban naturalization programs. Consequently, many urban environments are now inhabited by a much larger wildlife population than they were several decades ago. The more species present in the city, the greater the potential for human-wildlife interaction and/or conflict. Current municipal capacity for human-wildlife conflict management is generally insufficient to deal with growing problems. New solutions for human-wildlife conflict are needed. Using selected municipalities in southern Ontario as an example, this thesis research explores the development and application of principles for wildlife-human conflict management in urban areas. A literature review, media analysis and interviews with key municipal stakeholders were used to identify best management practices. Recommendations for the development of integrated nuisance management (INM) systems are proposed based on study findings.
Implementation of Preisach-Krasnoselskii Hysteresis Model with the Use of Artificial Neural Networks
Authors: Wang Zhao
Published: May 2021

Accurate modeling of hysteresis is essential for both the design and performance evaluation of electromagnetic devices. This project proposes the use of feedforward meural networks to implement an accurate magnetic hysteresis model based on the mathematical difinition provided by the Preisach-Krasnoselskii (P-K) model. Feedforward neural networks are a linear association networks that relate the ouput patterns to input patterns. By introducing the multi-layer feedforward neural networks make the hysteresis modeling accurate without estimation of double integrals. Simulation results provide the detailed illustrations. The comparisons with the experiments show that the proposed approach is able to satisfactorily reproduce many features of obsereved hysteresis phenomena an in turn can be used for many applications of interest.
Teach them to be expressive: an application of communication accommodation theory to vocal pedagogy
Authors: McKibbon Meghan
Published: May 2021

There is a large amount of overlap between the disciplines of singing and communication, particularly in the area of expression. Recent science based pedagogy written by Richard Miller is considered foundational knowledge in the vocal community, however, there are concerns that this anatomically focused pedagogy prevents the development of creative and expressive singers. A thematic analysis of two of Miller’s pedagogical texts was used to collect excerpts focused on the topic of expression. A second phase intention analysis revealed that the discussion of expression was largely uninstructive, providing teachers with minimal methodology. There is evidence that Miller addresses the importance of expression in vocal performance, however, his style of pedagogy does not allow for an in depth exploration of the tactics necessary for its instruction. Applying concepts from communication accommodation theory to the pedagogy will allow for the expansion of existing techniques such as modeling, convergence and divergence into the area of expression aiding vocal instructors in teaching the art of musical expression.
Interrogating psychocentrism and the role of a white researcher
Authors: Rovet Jordana
Published: May 2021

This work represents a culmination of experiences of individuals who have been subjected to adolescent psychiatrization and particularly, the influences of psychocentrism. This work builds upon the notion of psychocentrism as a social justice issue by exploring how its’ embeddedness within dominant mental health discourse functions to disregard the systemic, historical and cultural factors contributing to individual experiences of emotional distress. Through this analysis, the tensions of a white researcher with social justice aims is problematized and explored in tandem with the findings of this research.
The Effects Of Cell Cycle Synchronization On The Growth Potential Of Primary Articular Chondrocytes
Authors: Subedar Omar Dawood
Published: May 2021

Rapid production of cartilaginous extracellular matrix (ECM) is required for scale up of any articular cartilage tissue engineering approach. Although several different methods have been investigated to increase the rate of cartilaginous ECM synthesis (e.g. growth factor stimulation, mechanical loading, etc.), there is evidence to suggest that cell cycle synchronization increases rate of ECM deposition. The issue with primary articular chondrocytes (PACs) is that routine methods to synchronize cells within a particular phase of the cell cycle rely on the use of monolayer culture, which is known to elicit cellular de-differentiation. This required development of a novel method of synchronizing cells within the S phase of the cell cycle during cell isolation. The objective of this study was to test whether synchronizing PACs would improve deposition of cartilaginous ECM in a three-dimensional culture model. Findings suggested that cell cycle synchronization was a viable method of improving the rate of matrix deposition in PACs.