Department of Mechanical and Materials Engineering Graduate Theses

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    Advancing Industrial Smokeless Flaring: Experimental and Computational Studies into Swirl Air-Assist Burners
    (2024-07-11) Hou, Jianfeng; Mechanical and Materials Engineering; Birk, A. Michael
    The flame thermal radiation characteristics of two prototype swirl air-assist burner designs, associated with industrial smokeless flaring, were experimentally and computationally studied. The work was driven by two main interests: first, to explore the potential of swirling air-assist flare tips in reducing thermal radiation levels, decreasing soot emission, and stabilizing flames in cross-wind; second, to develop an affordable Reynolds Averaged Navier-Stokes (RANS) based computational fluid dynamics (CFD) methodology validated with these specific flames to facilitate further burner designs. The experimental investigation involved two burner configurations. The first burner, named the accelerating swirl burner, was evaluated using two-phase propane at rates of 3 kg/min and 6 kg/min. Compared to an open flare and the burner setting without assist air, the burner with a moderate active assist air supply effectively reduced the visible flame area and emissive power, while also enhanced flame stability in cross-wind. The second burner, called the diffusing swirl burner, equipped with two powerful centrifugal fans, was tested under assist-air to fuel ratio (AAFR) ranged from low, moderate, high to maximum. An increase in AAFR introduced recirculation regions near the burner outlet, led to reductions in visible flame area, emissive power, and radiative heat flux. CFD simulations of both swirl burners in ANSYS Fluent captured the general trends observed in experiments, such as decrease in flame size and emissive power. For the diffusing swirl burner, however, the flame shape responsiveness to AAFR changes in CFD lagged behind that in experimental observations, with flame area discrepancies ranging from 11%-42% compared to the flame contours observed at 800 K. Predictions of emissive power deviated from the experimental values by 3%-67%. Regarding soot production, the model predicted a maximum 84% reduction in soot volume fraction, closely aligning with the observed transition from slightly sooty to smokeless flames in experiments.
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    Wearable Sensor-Based Estimation of Spinal Loading in the Sagittal Plane during Fluoroscopic Procedures
    (2024-06-25) Brost, Samuel; Mechanical and Materials Engineering; Li, Qingguo
    Back injuries are one of the most common injuries and lead to significant amounts of lost work and years spent living with disability. It is essential to understand back-related work injuries by understanding the loading that exists within the spine. Unfortunately, within the healthcare sectors where there are high rates of back injury, there is no method to measure the loading. In fluoroscopic procedures, which require the use of X-rays, healthcare workers wear heavy protective equipment for long periods, while often in poor postures. The objective of this thesis was the design and development of a system capable of measuring sagittal plane spinal kinematics using inertial measurement units and modelling the spine based on the kinematics and limited individual-specific inputs to estimate cumulative spinal loading of healthcare staff performing fluoroscopic procedures. We first developed a wearable inertial measurement unit-based sagittal plane kinematic model that uses four inertial measurement units placed on the spine. We then developed a cervical spine model based on a thoracolumbar spine equivalent beam model. After developing the cervical model, the thoracolumbar model was modified to allow for the two sections to be combined. To verify the performance of the model in the desired environment, we performed, to our knowledge, the first estimations of cumulative spinal loading during fluoroscopic interventional and operative procedures. Ten healthcare workers from cardiology and orthopaedics were recorded performing fluoroscopic procedures. They were found to have quasi-static peak compression loading less than the 3400 N limit set by the National Institute for Occupational Safety and Health. A modified Mainz-Dortmund Dose model [1] was applied to calculate the daily cumulative load dose and found that eight participants exceeded recommended sex-based limits for daily loading at the L4/L5 intervertebrae region. The primary contribution of this work is the development of a sagittal plane spinal loading model capable of estimating cumulative loads through the entire spine from L5 to C1 using inertial measurement units and a spine equivalent beam method. This model allowed for the first investigation of cumulative loading of healthcare workers during live fluoroscopic procedures.
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    Access to Augmentative and Alternative Communication (AAC) Technology in Canada: Evaluation of Current System
    (2024-06-03) Henderson, Jillian; Mechanical and Materials Engineering; Davies, Claire
    Alternative and augmentative communication (AAC) systems enable persons to communicate, yet access to these devices is limited. In 2019, the Government of Canada introduced “The Accessible Canada Act”, an act to ensure a barrier-free Canada. However, its primary source for data collection on persons with disabilities (Canadian Survey on Disability) does not include communication disabilities in its list of disabilities, neglecting people with complex communication needs. This research sought to determine the barriers to accessing AAC technology in Canada. A scoping review was conducted to understand the identified barriers in literature that occur in Canada. Barriers are present in accessing services, funding, technology, and even about baseline knowledge required to access and use the system itself. Identification of associations to enable access included 43 government programs and charitable organizations. While the websites for charitable organizations were objectively easier to navigate than the government websites, both provided insufficient information to confirm AAC eligibility and often had outdated or unreliable links. Many websites do not conform to the World Content Accessibility Guidelines, applications are too difficult to read, and crucial program information is dispersed across multiple web pages, documents, and websites. There are numerous opportunities for information and documents to be misinterpreted, unnoticed, or forgotten. To gain access to AAC in Canada, there are different procedures based on the location in which one lives (rural, urban, province, territory), access to clinicians, and the ability to navigate websites and application procedures. As AAC device selection is limited through government programs and charitable organizations, the process of application to these programs must be clear and barrier-free. Optimization of services would greatly improve AAC access and improve the possibility of reaching a barrier-free Canada by 2040, the goal of the Accessible Canada Act.
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    Engineers’ Environmental Responsibility and Professional Engineering Codes of Ethics in Canada
    (2024-05-28) Randall, Emma Jane; Mechanical and Materials Engineering; Strong, David
    Engineers Canada states that engineers must, “Hold paramount the safety, health and welfare of the public and the protection of the environment and promote health and safety within the workplace” [1]. This is frequently the only guideline directly related to the environment included in Canadian provincial and territorial Professional Engineering Codes of Ethics (PECoE) which are a primary resource for teaching engineering ethics [1]; notably, Ontario’s PECoE currently does not explicitly mention the environment [2]. Minimal formal ethical guidelines indicate interpretations of engineers’ professional responsibility with respect to the environment may vary in both industry and engineering education. With the growing focus on sustainable development alongside escalating environmental crises, a thorough investigation of engineers’ professional ethical responsibility to the environment is time-sensitive and necessary [3]. The purpose of this study is to improve understanding of how engineers and engineering students view and interpret their professional ethical responsibility to the environment and PECoE in a Canadian context. Key conclusions from this research are that there was 100% consensus from participants that engineers do have a professional ethical responsibility regarding the environment, that there is significant variance by engineering discipline with respect exposure to engineering ethics education and the inclusion of environment, that case studies with relevant content are valuable modes of encouraging critical thinking with respect to engineering ethics, and that there is a need to explicitly include reference to the environment in the Ontario PECoE. The ultimate goal of this research is to aid the development of engineering ethics and sustainability curricula, as well as Professional Engineering Codes of Ethics.
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    Mechanical Testing and Characterization of Proposed Copper Materials for the Disposal of Used Nuclear Fuel Waste
    (2024-05-23) Poles, Taegen Michelle; Mechanical and Materials Engineering; Daymond, Mark
    For permanent and safe storage of Canada’s used nuclear fuel, it is proposed to contain and emplace the used fuel bundles in a deep underground repository where they will remain for long term storage. The used fuel containers (UFCs), made of copper-plated steel, must be designed and manufactured to be robust under diverse environmental conditions, including applied loads. In the analysis of proposed copper coatings of UFCs reported here, five types of material manufacturing and processing methods for the copper were examined within two main categories: electrodeposited (ED) or cold-sprayed (CS). Testing included scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD) imaging, tensile tests, and micro-computed tomography (MicroCT). The findings presented in this thesis highlight the significant impact of heat treatment on the mechanical properties of CS material, markedly reducing porosity and internal defects compared to the as-sprayed (AS) state. While electrodeposition yields a minimally porous copper structure, the composition of the electrodeposition bath influences mechanical behavior during straining. EBSD analysis of CS-AS material was constrained by high grain boundary proportions and heavily deformed grains, with annealing enhancing grain size uniformity. The material retained a mix of brittle and ductile fracture characteristics post-heat treatment at either 350 or 600°C. Porosity distribution was heterogeneous across CS samples, with annealing notably reducing identifiable porosity. SEM imaging revealed sub-micrometer pores on fracture surfaces, particularly at pore-particle interfaces. In uniaxial tensile tests on an interfacial sample, no delamination or significant localized strain occurred along the interface, demonstrating uniform behavior with necking observed through SEM imaging. This suggests the ductility of copper enables it to deform to match the steel under uniaxial strain, reducing delamination risk and maintaining protection during deformation. Moreover, the study highlights the influence of hydrogen content on material elongation tolerance, with ED-Acid samples exhibiting earlier failure compared to ED-Pyrophosphate tests. Fracture surface analysis revealed small-scale porosity in all failed samples, with digital image correlation mapping providing valuable insights into bulk behavior and fracture localization.