Engineering Commons^™

Laparoscopic Image Recovery And Stereo Matching, Wenyao Xia

Electronic Thesis and Dissertation Repository

Laparoscopic imaging can play a significant role in the minimally invasive surgical procedure. However, laparoscopic images often suffer from insufficient and irregular light sources, specular highlight surfaces, and a lack of depth information. These problems can negatively influence the surgeons during surgery, and lead to erroneous visual tracking and potential surgical risks. Thus, developing effective image-processing algorithms for laparoscopic vision recovery and stereo matching is of significant importance. Most related algorithms are effective on nature images, but less effective on laparoscopic images.

The first purpose of this thesis is to restore low-light laparoscopic vision, where an effective image enhancement method …

Effect Of Ion Implantation On Mechanical Properties And Kinetic Deformation Mechanisms In Inconel X-750, Loabat Shojaei-Kavan

Electronic Thesis and Dissertation Repository

The recent mechanical tests on the ex-service Inconel X-750 spacers have indicated significant embrittlement and reduced load carrying capacity compared to as installed condition. This is an immense safety concern to the nuclear industry, as in-service spacer examination and their replacement within fuel channels are very costly and impractical. The primary degradation mechanism is complex, and thus provides the focus of the current investigation. Despite few previous reports about hardness of non-irradiated and irradiated Inconel X-750, thermally-activated time-dependent deformation conditions have not been studied. This dissertation has attempted to overcome this scarcity of data by providing a series of fundamental …

A Partial-Turbulence Approach To Estimate Peak Wind Loads On Low-Rise Building Roofs, Yitian Guo

Electronic Thesis and Dissertation Repository

Quasi-steady (QS) theory is a commonly-used tool in wind engineering for the assessment of wind loads on structures induced by large-scale gusts. However, the QS-based approach tends to underestimate peak loads significantly since it fails to capture the effects of small-scale and body-generated turbulence. The objective of this thesis is to develop a method to estimate peak wind loads on low-rise roofs based on a partial-turbulence approach, i.e., using the QS vector model for loads induced by large-scale fluctuations from the incident flow, and a separate statistical model to account for the effects due to body-generated turbulence.

Wind tunnel tests …

Study Of Recyclable And Repairable Dynamic Covalent Polymers For Sustainable 3d Printing Development, Mingyue Zheng

Electronic Thesis and Dissertation Repository

3D printing technology with valuable features, including cost-saving, easy access, and unlimited structure design, has attracted significant attention and been employed for production use. This technology has also been considered as a sustainable manufacturing method and quickly developed in recent years. However, the development of sustainable 3D printing is still facing challenges, especially in waste management. Thanks to the flexibility of 3D printing and diversified printing mechanisms, the big step forward can be approachable by the transformation from materials. This dissertation presents a variety of strategies designed for sustainable 3D printing development based on the combination of dynamic covalent chemistry …

Full-Scale Field Study Of A Geogrid-Reinforced Unpaved Road System, Abdalla El Tawati

Electronic Thesis and Dissertation Repository

Geogrids are widely used to improve the performance of unpaved roads constructed over weak subgrade. However, the behavior of geogrids under traffic loads and their reinforcing mechanisms, as well as the resulting benefits to the roadway performance are not well understood. A full-scale field study was conducted to quantify the effectiveness of geogrids in unpaved roads, evaluate their reinforcing mechanism, and identify which geogrid properties are most directly related to performance improvement. Ten full-scale unpaved road test sections were constructed with varying relevant parameters including geogrid aperture shape, geogrid tensile modulus, and thickness of the base course layer. Five of …

Motion Intention Estimation Using Semg-Acc Sensor Fusion, Jose Alejandro Lopez

Electronic Thesis and Dissertation Repository

Musculoskeletal injuries can severely impact the ability to produce and control body motion. In order to regain function, rehabilitation is often required. Wearable smart devices are currently under development to provide therapy and assistance for people with impaired arm function. Electromyography (EMG) signals are used as an input to pattern recognition systems to determine intended movements.

However, there is a gap between the accuracy of pattern recognition systems in constrained laboratory settings, and usability when used for detecting dynamic unconstrained movements. Motion factors such as limb position, interaction force, and velocity, are known to have a negative impact on the …

Towards Multiclass Damage Detection And Localization Using Limited Vibration Measurements, Sandeep Sony

Electronic Thesis and Dissertation Repository

Traditional vibration-based damage detection methods provide structural health information based on their measured data (i.e., acceleration and displacement response). Over the last few decades, various model-based and time-frequency methods have shown great promises for damage identification and localization. However, the existing methods are unable to perform satisfactorily in many situations, including the presence of limited sensor measurements and training data, detection of minor and progressive damage, and identification of multiclass damage, creating constraints to make them free of user-intervention and implemented using the modern sensors. The main objective of this thesis is to develop algorithms capable of damage identification and …

Metallization Process For 3d Printed Electronics: From I3dp Ii To 3d Co-Printing Technology, Junfeng Xiao

Electronic Thesis and Dissertation Repository

3D printing has emerged as a powerful additive manufacturing technique and becomes as a viable alternative to conventional manufacturing processes in an increasing number of applications. Thus, the development of printable materials also continues to expand, while polymers are still the most utilized materials in 3D printing. There is a great advance for developing polymers with versatile mechanical and chemical properties. However, the end-use products are demanding various functions. It is imperative to develop functional 3D printed polymeric materials to achieve enhanced functionalities.

Usually, one polymer can meet one specific application. This has considerably limited the capability of 3D printing …

Experimental Simulation Of A Density-Driven Downburst Translating Within A Turbulent Boundary Layer, Shivani Ashitkumar Jariwala

Electronic Thesis and Dissertation Repository

Downburst outflows emerging from thunderstorm producing clouds are contained within the atmosphere where the outflow interacts with the preexisting atmospheric boundary layer (ABL). This novel study employs a realistic approach for experimental simulation of downbursts by translating the downburst source within a scaled ABL within a hydraulic flume system that produces open channel flow. The density-driven model approach is used, involving an iris operated cylinder release mechanism translating inside the ABL generated over a restrictive fetch using passive turbulence generating devices at model scales of 1:5500 and 1:10,000. The velocity vector fields across a vertical plane revealed asymmetrical outflows generated …

Finite Element Analysis Of Assembly For Warped Composite Automotive Components, Theogenes De Oliveira Maia

Electronic Thesis and Dissertation Repository

One of the most used processes in the automotive industry is the moulding of parts made of thermoplastics filled with glass fibres. This research focused on a specific material: long fibre thermoplastics (LFT). On the one hand, the performance gain, in terms of lightweight and the strength of final components, justifies its wide use. On the other hand, due to the intrinsic characteristics of part manufacturing, warpage is evident and can influence or even compromise subsequent stages of production.

This research has three main objectives: recreate in the most faithfully way, in Abaqus^TM environment, the conditions that precede the …

Finite Element Analysis Of Buckling Capacity Of Conical Steel Tanks Considering Field-Measured Initiation Imperfections – A Case Study, Haoyi Zhang

Electronic Thesis and Dissertation Repository

The geometric imperfection in elevated steel conical water tanks is a key factor that influences the buckling capacity of the tank. Current considerations of imperfections in the design of conical tanks are based on theoretical analysis, whereby the imperfection shapes and locations are assumed to have the most critical impact on the capacity. This thesis investigates the initial imperfections of an actual stiffened liquid-filled steel conical tank (LFCT) based on high-resolution laser scan measurement data of the tank geometry.

In the first part of this study, detailed analyses of the laser scan data were carried out to extract the global …

Impact Of Artisanal And Small-Scale Mining On Water Bodies And Treatment: The Case Of Birim River Basin In Ghana, Adwoa Boadua Yirenkyi Fianko

Electronic Thesis and Dissertation Repository

Water bodies, the source of drinking water for many rural households in mining areas are at risk of contamination due to artisanal and small-scale mining (ASM) activities. Water quality, therefore, remains a topical issue for policymakers and researchers.

This research sought to achieve three objectives: firstly, to evaluate the effectiveness of existing policies and regulations about ASM in protecting waterbodies. Secondly, to determine the impact of ASM on waterbodies, health and livelihood of inhabitants in mining communities and thirdly, to remove heavy metals from water using locally available bio-adsorbents such as moringa seeds, coconut and corn husks.

A survey of …

Cluster Acceleration And Stabilization In Downflow Catalytic Reactors: Experimental And Cpfd Simulation Studies, Cesar Alejandro Medina Pedraza

Electronic Thesis and Dissertation Repository

Particle cluster dynamics in downflow reactors are of great importance for the implementation of large scale, environmentally friendly catalytic processes. Studies should address particle cluster velocities, solids holdups, and individual cluster sizes to establish reliable models for the unit scale up.

In this PhD dissertation, the individual characteristics of particle clusters, such as cluster size, velocity, and particle volume fraction, were measured in the feeding, intermediate, and fully developed flow sections of a cold-flow model unit using CREC-GS-Optiprobes. The downer unit employed in this research had a 0.051 m ID and a 2 m high acrylic column. The feeding section …

Development Of A Recombinant Brewing Yeast To Produce Beer From Hemp Extract (Cannabis Sativa L.), Mehmet Ugur Gulmen

Electronic Thesis and Dissertation Repository

The Cannabis industry is a rapidly-growing market in Canada. With the legalization of edible products in 2019, many cannabis-derived candies, baked goods, beverages appeared on shelves. Cannabis beer can be brewed by replacing barley with pretreated cannabis plant. However, using a traditional brewing yeast to brew cannabis beer will result in incomplete fermentation which will affect the beer’s composition and flavour because traditional brewing yeasts are not able to utilize xylose which is an abundant carbohydrate in lignocellulosic extracts. Using a recombinant strain of a brewing yeast and a xylose-fermenting yeast can overcome this issue. The work presented in this …

Enhanced Primary Sludge Fermentation And Anaerobic Digestion For Integrated Carbon Upgrade And Resource Recovery, Gholamreza Bahreini

Electronic Thesis and Dissertation Repository

The emerging paradigm shift towards renewable resource recovery, and energy minimization in municipal wastewater treatment plants (WWTPs) coupled with increased concern over nutrients-related eutrophication accelerated the development of biosolids treatment technologies for simultaneous waste minimization, resource recovery, and carbon upgrade. Biological nutrient removal (BNR) processes, often need excess carbon source to meet stringent quality standards. Despite successful use of sludge fermentation liquid to enhance the BNR, different techniques, are applied to improve the low conversion yield of fermentation and optimize resource recovery. In this context, insights on the impact of two commonly used primary treatment techniques (i.e. conventional primary clarifier …

Experimental Study Of Tornado-Induced Pressures, Aya Kassab

Electronic Thesis and Dissertation Repository

The increased devastation associated with tornadic flow-fields in terms of human lives or destruction of properties and their subsequent economic losses highlights the significance of understanding the tornado vortex structure, particularly near the ground where the majority of this destruction happens. While the body of research in this area is increasing there is a lack of resolution associated with physical near-surface measurements in tornado-like vortices (TLVs) and the effects of translation, surface roughness, and surface vortex dynamics are not yet well understood.

In order to address these gaps, high spatial and temporal surface pressure measurements were carried out at WindEEE …

In Vitro Analyses Of The Contributions Of The Hip Capsule To Joint Biomechanics, Emma Donnelly

Electronic Thesis and Dissertation Repository

Optimal management of the hip capsule during arthroscopic surgery has not been established. The impact of incisions made to the capsule during minimally invasive procedures on joint biomechanics, and whether repair provides any benefit, continue to be debated. The effectiveness of capsular repair to restore native kinematics may be insufficient. Therefore, a better understanding of joint behavior during various capsule conditions is needed. A new robotic system was used to analyze the effect of progressive capsulotomy incision and repairs on the behavior of a normal hip within range of motion (ROM) limits with respect to the intact joint. Complete repairs …

New Experimental Methods For Modelling Canopy Problems, Marilena Enus

Electronic Thesis and Dissertation Repository

The challenge in large scale experimental fluid dynamics comes from the demand to develop simple methods that can measure and model movement of flexible objects and wind flow over large three-dimensional volumes with readily available equipment. Representing and modelling the flow around trees is challenging mainly because of the complexity and variability of trees. In this research different methods were tested in the novel Wind Engineering Energy and Environment (WindEEE) Dome facility at Western University, Canada to capture displacements of a moving single tree and flow velocities over a model forest edge in a three-dimensional form. The tested measuring methods …

Immobilized Jagged1 For Notch3-Specific Differentiation And Phenotype Control Of Vascular Smooth Muscle Cells, Kathleen E. Zohorsky

Electronic Thesis and Dissertation Repository

Notch signaling plays a critical role in regulating vascular morphogenesis. In vascular interventions, the endothelial cells (ECs) are often damaged, and EC-SMC contact is compromised. The objective of this study was to investigate if immobilized Jagged1 can act as an EC-surrogate material to direct and control vascular smooth muscle cell (VSMC) behavior via Notch signaling. It was shown that immobilized Jagged1 induced vascular differentiation of iPSC-derived mesenchymal stem cells and mouse embryonic multipotent cells. Immobilized Jagged1 was insufficient to induce mature contractile markers in coronary artery SMCs; therefore, serum starvation and TGFβ1 treatment were investigated. Although Notch signaling is mechanosensitive …

Design, Development, And Evaluation Of Customized Electronics For Controlling A 5-Dof Magneto-Rheological Actuator Collaborative Robot, Ziqi Yang

Electronic Thesis and Dissertation Repository

In recent years, Magneto-Rheological (MR) fluids has been used in various fields such as robotics, automotive, aerospace, etc. The most common use of the MR fluids is within a clutch-like mechanism, namely an MR clutch. When mechanical input is coupled to the input part of the MR clutch, the MR clutch provides a means of delivering this mechanical input to its output, through the MR fluids. The combination of the mechanical input device and the MR clutch is called an MR actuator. The MR actuator features inherently compliance owing to the characteristic of the MR fluids while also offering higher …