Experimental Investigation Of Inverse Liquid-Solid Fluidized Bed Hydrodynamics, Saleh A. Srabet

Electronic Thesis and Dissertation Repository

Abstract

Inverse liquid-solid fluidized beds have recently received increased attention, particularly for use with wastewater treatment bioreactors (i.e., particle-supported biofilms). The flow behaviour of free-rising light particles is especially interesting because their drag coefficients deviate from the standard drag curve. For this reason, the work presented in this thesis was focussed on investigating the minimum fluidization velocity () and the steady-state bed voidage associated with four particles, with densities of 28, 122, 300, and 678 kg/m³, in a conventional inverse fluidization regime. All experimental measurements were completed using a large-scale system comprising a downer column with a diameter …

The Effect Of Humeral Short Stem Positioning, Humeral Head Contact, And Head Positioning On Bone Stress Following Total Shoulder Arthroplasty, Amir Tavakoli

Electronic Thesis and Dissertation Repository

Uncemented humeral stems cause stress shielding which result in bone resorption when used in total shoulder arthroplasty (TSA). Shorter length stems show a decrease in stress shielding, however the effect of humeral short stem positioning and humeral head contact and positioning on bone stress is currently not known, hence CT-based tools and Finite Element (FE) methods are used to quantify the effects of the mentioned variables on bone stresses after TSA.

Eight male cadaveric humeri were virtually constructed from computed tomography (CT) data, with a generic short humeral short stem as the implant.

The results of this work show that …

An Investigation On The Influences Of Radial Head Hemiarthroplasty Stem Fixation Techniques On Articular Mechanics, Jakub Szmit

Electronic Thesis and Dissertation Repository

Radial head hemiarthroplasty design has been extensively studied with a focus on utilizing the geometrical characteristics of the native radial dish as a guide of implant placement and design. Although implant design has been studied, optimal radial head implant fixation technique remains unknown. This thesis focused on the effect of stem fit on radiocapitellar contact mechanics, using both finite element and experimental bench-top approaches. Additionally, investigation into the impact of varus/valgus malalignment of the radial head in both the native state and following hemiarthroplasty was conducted. It was found that loose fitting a smooth stem axisymmetric radial head implant through …

Characterization For Spray Droplet Behaviour In Afterburner-Like Flow Conditions, Matthew D. Mahaffy

Electronic Thesis and Dissertation Repository

Fuel injection processes can contribute to combustion instability in highly energetic combustion systems. In gas turbine engine afterburners, jet-in-crossflow (JIX) injection is used. Part one of the thesis study investigates the interaction between spray droplets and turbulent flow properties of a JIX. Jet-in-counterflow (JIC) configuration was also investigated. Part two of the investigation examined the behaviour of JIX droplets around a bluff body. Droplet size and flow turbulence was characterized simultaneously using particle image velocimetry and image processing techniques. Turbulence and droplet size were correlated, particularly at momentum flux ratios ≥ 60. High speed imaging was used to identify droplet …

Evaluation Of Warpage For Composite Automotive Components, Eric J. Martin

Electronic Thesis and Dissertation Repository

Thermoplastic composite parts are manufactured using compression molding for the purposes of assembly in a car seat sub-assembly. Concerns about the dimensional accuracy of the parts prompted an investigation into the part warpage. The warpage of the parts needs to be evaluated for the purposes of determining processing conditions which are linked to part warpage, in order to reduce part warpage.

Laser line probes (LLP) are becoming a more attractive tool for the purposes of part inspection. LLPs quickly acquire point cloud data from complex surfaces and are a non-contact method of measurement; these qualities make LLPs the best tool …

Analytical And Computational Modelling Of The Ranque-Hilsch Vortex Tube, Nolan J. Dyck

Electronic Thesis and Dissertation Repository

The Ranque-Hilsch vortex tube (RHVT) is a simple mechanical device with no moving parts capable of separating a supply of compressed fluid into hot and cold streams through a process called temperature separation. The overall aim is to develop models which can be used to assess the temperature separation mechanisms in the RHVT, leading to a better overall understanding of the underlying physics. The introductory chapter contains a thermodynamic analysis and introduction to the flow physics, alongside three miniature literature reviews and critiques identifying research gaps.

The body of the thesis contains three articles. The first article studies the flow …

Sustainable Smouldering For Waste-To-Energy: Scale, Heat Losses, And Energy Efficiency, Tarek L. Rashwan

Electronic Thesis and Dissertation Repository

Applied smouldering combustion is emerging as a highly energy efficient approach towards waste-to-energy. This thesis aims to better understand this potential by addressing a critical knowledge gap between laboratory scale smouldering research and large-scale applications. Altogether, new understanding in provided on the complex and dynamic interactions between the reaction zone (smouldering front) and the cooling zone (treated inert porous media) by integrating theory, experiments, analytical modelling, and global energy balance calculations. The experiments spanned a range of reactor sizes and smouldering conditions (from weak to robust) with dry (carbon) and wet (sludge) fuels mixed in sand. This work revealed that …

Experimental Modelling Of Downburst And Downburst Line Outflows, Kyle Graat

Electronic Thesis and Dissertation Repository

The outflow velocity vector fields of simulated stationary thunderstorm downbursts and downburst lines were resolved in two plane orientations, vertical and horizontal, using a dense fluid release system and Particle Image Velocimetry. Single event releases were scaled to show agreement with past studies based on radial velocity magnitude and location and radial and vertical front propagation. The vortex trajectory of a single event using the vortex aspect ratio supported density's role in the outflow after the time and location of the maximum radial velocity. The interaction between two release events varied temporally and spatially and showed that the interaction region's …

Development Of An Optical Guide For Parabolic Dish Solar Collectors, Zane Charran

Electronic Thesis and Dissertation Repository

With the possibility of a global energy crisis on the horizon, the need for renewable energy processes is more crucial than ever before. Solar energy, specifically solar concentrated collectors can provide a green alternative to fossil fuel consumption, but several factors need to be considered to improve their efficiency and make them viable. The present research is aimed at the development of a novel “Optical Guide” to improve performance of traditional thermal receivers in Parabolic Dish Solar Collectors for use in a domestic solar water heater with PCM latent heat storage integration. Two ray trace programs, SolTrace and Tracer were …

The Effect Of Free-Stream Turbulence On Turbulent Boundary Layers And Convective Heat Transfer From Flat Plates, Ivian Carolina Alfaia De Magalhaes

Electronic Thesis and Dissertation Repository

The present work investigates the effect of free-stream turbulence (FST) on turbulent boundary layers and forced convective heat transfer from flat plates. High resolution, 2-D and 3-D, steady Reynolds-Averaged Navier-Stokes (RANS) simulations using Computational Fluid Dynamics (CFD) techniques were performed to analyze the influence of different free-stream conditions, such as turbulence intensity (TI), integral length scale (L_u) and free-stream velocity (U_o) on local and total skin friction and convective heat transfer coefficients (CHTC), as well as on turbulent boundary layer parameters (boundary layer thickness and momentum thickness). The present study shows that …

Parametric Study Of The Cutting Process And Surface Formation During Elliptical Vibration Assisted Single Point Cutting, Nikolai D. Farrus

Electronic Thesis and Dissertation Repository

Elliptical vibration cutting has enabled the fabrication of numerous functional surfaces such as optical quality surface finishes, micro/nano surface texturing, and improved cutting force reduction on ferrous and other hard‑to‑cut materials. This wide range of capabilities comes from the high‑frequency elliptical vibrations produced at the tool tip, ultimately introducing discontinuous contact between the cutting tool and workpiece. However, despite the relative use of this technology, there has been limited investigation on the overarching parametric influence that its cutting parameters have on process outcomes such as cutting forces and surface roughness formation.

The current thesis addresses this research gap with the …

Effect Of Moving Boundary On Fluid Flow, Kh Md Faisal

Electronic Thesis and Dissertation Repository

The peristaltic pumping through channels with vibrating walls has been studied. The vibrations take the form of traveling waves. The spectrally accurate algorithm used to study flow properties is based on the Fourier expansions in the flow direction, Chebyshev expansions in the transverse direction, and the immersed boundary conditions (IBC) concept to deal with the irregular form of the solution domain associated with the waves. The flow domain is immersed in a regular computational domain. The flow boundary conditions are imposed in the form of constraints. Effectiveness of peristaltic pumping is assessed by determining the variation in the flow rate …

The Study Of Bubble Growth Hydrodynamics In The Supersaturated Liquids, Raj Kumar Nayak Maloth

Electronic Thesis and Dissertation Repository

Bubble formation and dissolution have a wide range of industrial applications, from the production of beverages to foam manufacturing processes. The rate at which the bubble expands, or contracts has a significant effect on these processes. In the current work, the hydrodynamics of an isolated bubble expanding due to mass transfer in a pool of supersaturated gas-liquid solution is investigated. The complete scalar transportation equation (advection-diffusion) is solved numerically and it has been observed that the present model predicted an accurate bubble growth when compared with existing approximated models and experiments. The effect of gas-liquid solution parameters such as inertia, …

A Computational Investigation Into Acromial Fractures After Reverse Total Shoulder Arthroplasty, Jason Lockhart

Electronic Thesis and Dissertation Repository

Acromial fractures are a debilitating complication following reverse total shoulder arthroplasty (RTSA). The purpose of this work is to (1) improve the current state of FE bone stress estimates after RTSA and to investigate the effects of (2) plane of elevation, (3) hand loads, and (4) baseplate screw position on scapular spine stress. The FE method used was validated against an in-vitro strain gauge based experiment and found to be accurate in the prediction of stress increases and decreases after RTSA. The coronal plane of elevation was found to increase scapular spine stress compared to more central planes of elevation. …

Experimental Investigation Of Flow And Thermal Behavior In Channels With Pcm-Filled Thermal Energy Storage Columns For Potential Application In Photobioreactors, Kira Toxopeus

Electronic Thesis and Dissertation Repository

Microalgae has been identified as a potential source for the production of biofuels and other bio-products. The growth of microalgae is sensitive to the temperature variations inside the photobioreactor. The present research investigated an innovative approach to thermally regulate photobioreactors by introducing passive thermal energy storage using phase change material (PCM). The research was specifically focused on a novel design to integrate thermal storage in the reactor channel in the form of offset columns containing PCM. Two column shapes were considered: circular and square. The first part of the study was focused on characterizing the influence of offset column shapes …

Strategies For Ultraprecise Single Point Cutting Of V-Grooves, Delfim A C Joao

Electronic Thesis and Dissertation Repository

V-groove microstructures have found numerous functionalization applications in mechanical, electronic, photonic, biomechanical and optical components. However, despite their wide use, the manufacturing processes associated with their fabrication are limited to axial strategies with a constant depth of cut that do not allow the control of the cutting force and cutting time, and therefore leading to significant micro-burrs as well as an inability to fabricate high aspect ratio grooves. The current thesis addresses this problem with the development of three cutting strategies that make use of a single point cutting process. The study to be detailed herein includes analytical, numerical and …

Lower Stiffness Orthopaedic Implants For Hemiarthroplasty, Carolyn Berkmortel

Electronic Thesis and Dissertation Repository

One of the main drawbacks of hemiarthroplasty is that it involves the articulation of a foreign material against the native cartilage, and hence the native cartilage experiences accelerated wear. It is hypothesized that lowering the stiffness of hemiarthroplasty implants will decrease contact pressure and increase contact area, thus decrease wear. Lowering the stiffness was done using finite element analysis to lower the stiffness of the implant materials, and then to change the internal structure of the implants to increase their compliance. Structural changes produced no noticeable or favourable results, whereas material produced improved results for stiffnesses below a Young’s modulus …

Biomechanical Analysis Of Open-Skull High-Rate Traumatic Brain Injury Using Finite Element Mouse Brain Model, Lihong Lu

Electronic Thesis and Dissertation Repository

To better understand traumatic brain injury (TBI), it is necessary to correlate with injuries, which are observed from in vivo laboratory experiments, to brain mechanical responses, which can so far be best predicted by finite element (FE) models. Firstly, a previously validated FE model was improved to investigate the effect of repeated impacts and lateral movements on brain responses to ensure the accuracy and reproducibility of controlled cortical impact (CCI) across different labs. Then, a new FE mouse brain model with the detailed three-dimensional (3D), non-linear vasculature was developed to study how the vasculature affected brain response in CCI and …

Energy Modelling To Evaluate The Thermal Regulation Of Aquaculture Raceways Using Geothermal Heat Exchange, Mitchell H. Kuska

Electronic Thesis and Dissertation Repository

Raceways are used in the aquaculture industry to farm fish species that swim against an upstream current. Raceways often draw water from a large waterbody and hence, their temperature changes due to seasonal variation, which directly affect the production yield. This study investigates a novel approach to regulate the raceway water temperature in a sustainable way by utilizing geothermal energy exchange. Energy models were developed to simulate heat transfer in a geothermal borehole heat exchange system and in the raceway system. The two models were then coupled to simulate the thermal regulation of the raceway water via borehole heat exchangers. …

Numerical And Semi-Analytical Estimation Of Convective Heat Transfer Coefficient For Buildings In An Urban-Like Setting, Anwar Demsis Awol

Electronic Thesis and Dissertation Repository

Urban building arrangements such as packing density, orientation and size are known to influence the microclimate surrounding each building. Studies on the impact of urban microclimatic changes on convective heat transfer coefficient (CHTC) from a stock of buildings, however, have been rare in surveyed literature. The present study focuses on numerical and analytical investigation of CHTC from building-like models with homogeneous set of equal and unequal planar and frontal densities. Consequently, the study discusses the CHTC response in relation to broader changes in the urban surface form. Part of the process involves the development of a simplified one-dimensional semi-analytical CHTC …

Characterization And Computational Modelling For The Garnet Oxide Solid State Electrolyte Ta-Llzo, Colin A. Versnick

Electronic Thesis and Dissertation Repository

The all-solid-state-battery (ASSB) serves as a promising candidate for next generation lithium ion batteries for significant improvements in battery safety, capacity, and longevity. Of the material candidates researched to replace the conventionally used liquid electrolyte, the garnet oxide Ta-LLZO (Li_6.4La₃Zr_1.4Ta_0.6O₁₂) has received much attention thanks to its high chemical and electrochemical stability, and ionic conductivity which rivals that of liquid electrolytes. While much investigation has taken place regarding the electrochemical performance of Ta-LLZO, much less is known about the micromechanics, including microstructural characterization, stress and strain development, and material failure …

A Wearable Mechatronic Device For Hand Tremor Monitoring And Suppression: Development And Evaluation, Yue Zhou

Electronic Thesis and Dissertation Repository

Tremor, one of the most disabling symptoms of Parkinson's disease (PD), significantly affects the quality of life of the individuals who suffer from it. These people live with difficulties with fine motor tasks, such as eating and writing, and suffer from social embarrassment. Traditional medicines are often ineffective, and surgery is highly invasive and risky. The emergence of wearable technology facilitates an externally worn mechatronic tremor suppression device as a potential alternative approach for tremor management. However, no device has been developed for the suppression of finger tremor that has been validated on a human.

It has been reported in …

Airborne Topological Acoustics, Xingxing Liu

Electronic Thesis and Dissertation Repository

Advances in topological acoustics are leading to potential development for noise attenuation, ultrasonic imaging, sound manipulation, and information delivering, etc. Recently, ideas and methodologies from condensed-matter physics, such as the quantum Hall effect (QHE), the quantum spin Hall effect (QSHE), and the quantum valley Hall effect (QVHE), combined with configurations of sonic crystals and metamaterials, have been investigated in manipulating acoustic transmissions in the form of one-way edge modes and defect-immune protected acoustics. However, many related studies are still in their infancy and mostly rely on bulky, noisy, overly complicated, untunable and narrow-band-effective facilities, and so it is highly desirable …

Validation Of Rhocentralfoam For Engineering Applications Of Under-Expanded Impinging Free Jets, Peter Nielsen

Electronic Thesis and Dissertation Repository

A numerical validation study of under-expanded impinging jet is conducted using OpenFOAM, an open-source computational fluid dynamics (CFD) library. RhoCentralFoam, a density based, compressible flow solver with a two-equation shear stress transport (SST) turbulence model is used on an axisymmetric model to reduce the computation cost. Major features of the flow were compared to an experimental study by Henderson et al., with a nozzle pressure ratio (NPR) of 4.0 and nozzle to plate spacing between 1.65-4.16. Of the features measured, the Mach diamond spacing, super-sonic core, and shear layer are all accurately predicted, while the recirculation bubble in the impingement …

Understanding The Interplay Between Fluid Mechanics And Particle Size Distributions For Filtration Of Flocculated Mixtures, Brooke Remler

Electronic Thesis and Dissertation Repository

The breakdown of nutrients in biological processes in wastewater treatment require a sub- stantial amount of energy, contributing to greater greenhouse gas (GHG) emissions. Floc- culation can be used to reduce the loading on a biological process by increasing removals during primary treatment in devices such as a rotating belt filter (RBF). The relationship between shear conditions, defined by velocity gradients (G-values) and floc size is crucial. Understanding G-value magnitudes and distributions within an RBF, corresponding trans- port network, and the effects on floc size degradation are needed to maximize removals. G-values were calculated using a newly developed approach, improving …

A Heterogeneous Patient-Specific Biomechanical Model Of The Lung For Tumor Motion Compensation And Effective Lung Radiation Therapy Planning, Parya Jafari

Electronic Thesis and Dissertation Repository

Radiation therapy is a main component of treatment for many lung cancer patients. However, the respiratory motion can cause inaccuracies in radiation delivery that can lead to treatment complications. In addition, the radiation-induced damage to healthy tissue limits the effectiveness of radiation treatment. Motion management methods have been developed to increase the accuracy of radiation delivery, and functional avoidance treatment planning has emerged to help reduce the chances of radiation-induced toxicity. In this work, we have developed biomechanical model-based techniques for tumor motion estimation, as well as lung functional imaging. The proposed biomechanical model accurately estimates lung and tumor motion/deformation …

The Hydrodynamics And Heat Transfer Of Impinging Jet Flow And Circular Hydraulic Jump, Yunpeng Wang

Electronic Thesis and Dissertation Repository

The laminar axisymmetric flow and heat transfer of a circular impinging jet and hydraulic jump on a solid surface is analyzed theoretically using boundary-layer and thin-film approaches. Liquid jet impingement features many applications such as jet rinsing, jet cooling, liquid atomization and chemical reactors. The associated hydraulic jump dramatically affects the performance of the heat and mass transfer in such applications. In the current thesis, the effects of inertia, surface tension, surface rotation, gravity and heat transfer are comprehensively explored for impinging jet flow and the formation of hydraulic jump.

The boundary-layer heights and film thickness are found to diminish …

An Experimental Study On The Impact Of Pressure Drop In The Ranque-Hilsch Vortex Tube, Mark Parker

Electronic Thesis and Dissertation Repository

A vortex tube converts a single stream of compressed gas into two outlet streams; one heated, and the other cooled. This phenomenon, referred to as energy separation, is not fully understood, thereby requires further experimentation and analysis. CFD can provide insight, however, such simulations require a complete set of information of the geometric, operational, and performance parameters of particular vortex tube experiments.

An experiment is developed to provide complete information for CFD simulations. The vortex tube under consideration is established by considering reported data from past studies and selecting parameters that yield significant energy separation. An experimental apparatus is developed …

In Vitro Biomechanical Analyses Of The Pcl And Medial Ligaments Of The Human Knee, Alireza Moslemian

Electronic Thesis and Dissertation Repository

Previous studies have shown that surgical treatments of PCL injuries are not successful in all cases and there is room for improvement. The effectiveness of an isolated PCL reconstruction, in the setting of what actually is a multi-ligament injury, may be inadequate, and therefore the biomechanical contribution of other ligaments in a PCL-deficient knee need to be better understood.

A new apparatus was used to analyze the effect of medial ligaments transection on the kinematics of the PCL-deficient knee during simulated clinical tests and activities of daily living. We observed that the anterior translation of the medial side of the …

Pneumatic Hyperelastic Robotic End-Effector For Grasping Soft Curved Organic Objects, Alexandre Galley

Electronic Thesis and Dissertation Repository

Pneumatically-driven soft robotic grippers can elastically deform to grasp delicate, curved organic objects with minimal surface damage. However, common actuators have complex geometries and are fabricated with ultra-soft hyperelastic elastomers not originally intended for scientific applications. The complexity of the actuator geometry and extreme nonlinearity of their material’s stress-strain behaviour make it difficult to predict the actuator’s deformation prior to experimentation. In this work, a compact soft pneumatic gripper made with polydimethylsiloxane (PDMS) is developed for grasping delicate organic objects, analyzed through computational modelling and experimentally validated. COMSOL Multiphysics is used to simulate the impact of geometrical parameters on the …