Mechanical Engineering Commons^™

Modeling Thermosyphon And Heat Pipe Performance For Mold Cooling Applications, Dwaipayan Sarkar

Electronic Thesis and Dissertation Repository

Thermosyphons are enhanced heat transfer devices that can continuously transfer very large amounts of heat rapidly over long distances with small temperature differences. The high heat transfer rate is achieved through simultaneous boiling and condensation of the working fluid and the continuous heat transfer is achieved through recirculation of the working fluid in its liquid and vapor phase. A potentially important application of the thermosyphons has been towards reducing the cycle times of the mold cooling processes which would provide economic incentives to the automotive industry.

Different operational and geometrical parameters such as the input heating power, fill ratio (FR), …

Analyses For Assessing The Centreline Translation, Asymmetrical Wind-Field, And Velocity Fluctuations Of Tornado Vortices, Niall C. Bannigan

Electronic Thesis and Dissertation Repository

Tornadoes present an ever-increasing threat to communities worldwide, especially those with geographic conditions that place them in the path of several tornadoes annually. These conditions are likely to be exacerbated by ongoing trends in the climate. As such, it is necessary to move towards experimental and numerical tornado-like vortex studies that allow for more advanced simulation methods. Novel techniques for tracking and analysing tornado vortices simulated at high spatial and temporal resolution are presented herein. Significant wandering of the tornado's position and large peaks in the velocity field can be captured, demonstrating tangential gusting at more than 1.5 times the …

Investigation Of Thermofluid Processes In A Pcm Based Thermal Storage Module, Luca M. Crnjac

Electronic Thesis and Dissertation Repository

Latent heat thermal energy storage systems can capture and store solar thermal energy, enhancing the reliability of solar energy by facilitating a continuous and consistent energy supply. However, phase change materials used in these systems suffer from low thermal conductivities making it difficult to achieve suitable charging and discharging rates. The present research investigated this issue using computational and experimental approaches to improve the design of a thermal storage module through heat transfer enhancement. Various heat transfer enhancements including a finned honeycomb structure, and metal wool were incorporated into a thermal storage module to analyze their effect on charging and …

Characterizing Tkr Biomechanics Using A Novel Muscle-Driven Joint Motion Simulator, Alexandre Galley

Electronic Thesis and Dissertation Repository

Total knee replacement (TKR) is the end-stage treatment for severe cases of knee osteoarthritis (OA). Despite its success in alleviating pain and restoring mobility to the knee, patient satisfaction rates post-TKR are still lower than other common joint replacement surgeries. Knee kinematics and stability, key determinants of successful TKR, are assessed intraoperatively and tracked post-operatively in in vivo clinical studies. However, the persistently low satisfaction rates suggest that more sophisticated pre-clinical testing methods are needed to better understand the biomechanics of these implants early in their development. During pre-clinical testing of TKR implants, different joint motion simulators are used for …

Study Of Multi-Dimensional Transfer Effects In Applied Smouldering Systems, Seyed Ziaedin Miry Mr

Electronic Thesis and Dissertation Repository

Smouldering is a flameless form of combustion that is driven by oxygen directly diffusing into the surface of condensed phase fuel (liquid or solid) and involves a complex interplay between heat and mass transfer through porous media, chemical reactions, and multiphase flow. Applied smouldering systems have been gaining popularity for a variety of applications including (i) energy and resource recovery, (ii) waste-to-energy, (iii) pyrolysis and gasification, and (iv) applied smouldering of organic liquids/solids for environmental benefits. In all contexts, smouldering is a complicated oxygen-limited phenomenon where multi-dimensional transfer effects (i.e., non-uniformities in …

Understanding Real-World And Laboratory Traumatic Brain Injury (Tbi) Using The Computational Model With Brain Functional Regions, Kewei Bian

Electronic Thesis and Dissertation Repository

Traumatic brain injury (TBI), including mild traumatic brain injury (mTBI) or concussion, is a severe health concern. Many symptoms, such as headache, dizziness, and working memory deficits, are reported to be related to the dysfunction of brain functional regions, but the underlying mechanism remains unknown. Hence, further developing tools and analyses to understand brain dysfunction for better TBI prevention are important. Additionally, such analyses should be conducted for both real-world TBI cases and laboratory studies, as TBI data can only be collected from the real world, and prevention measures, such as helmets, are developed and evaluated in the lab. Accordingly, …

Performance Recovery Of Scale Reduced Cyclone Particle Separators Using A Rotating Classifier, Mark J. Parker

Electronic Thesis and Dissertation Repository

Cyclone particle separators are often used to collect particles that are of value or environmental concern. These devices achieve high Total Collection Efficiency (TCE) with steady pressure drop. Increasing the height of the cyclone improves both TCE and pressure drop. However, due to the height of the cyclone, these devices are often forced to be placed outside, which can lead to decreased performance over time. The research examines the outcome of scale reducing a cyclone. This is achieved by (i) how the scale reduction changes the flow field, (ii) identifying what flow aspects contribute to the reduction in TCE and …

An Investigation Into Computational Modelling Of Melting And Solidification Of Phase Change Materials, Maryam Hemmat

Electronic Thesis and Dissertation Repository

This thesis evaluates the effectiveness of the enthalpy-porosity approach in simulating melting and solidification of phase change materials within latent heat thermal energy storage systems. It systematically investigates the sensitivity of the computational model to four adjustable parameters: mushy zone coefficient, thermal expansion coefficient, solidus/liquidus temperatures, and latent heat. The study includes individual and combined analyses of these factors in simulations of the melting process by comparing outcomes with extensive experimental data, resulting in a calibrated melting model. The calibrated model is validated across various heating conditions in the cylindrical cavity, and then in a rectangular cavity, confirming its reliability …

Patterned Heating Induced Propulsion, Saajid A. Aman

Electronic Thesis and Dissertation Repository

This study explores propulsion effects generated by patterned heating acting on smooth and corrugated surfaces. The model problem assumes that the upper plate moves freely, and the lower plate is stationary, equipped with grooves, and exposed to spatially distributed heating. Our findings identify two distinct propulsion effects: thermal streaming and thermal drift. Thermal streaming occurs when given sufficient heating intensity with net flow in the left or right direction characterized by a pitchfork bifurcation. The efficiency of this technique can be controlled using the wavelength of heating. Thermal drift represents a pattern interaction effect. Its strength depends on the relative …

Head Impact Effects In Small Remotely Piloted Aircraft System (Srpas) Collisions: Gender Specific Risks And Vulnerable Population Protection, Md Farhan Hoque Sagar

Electronic Thesis and Dissertation Repository

This study focuses on supporting the development of safety regulations for vulnerable populations during drone to head impacts. First, the small female head and neck model was compared to cadaveric data. Then, combined with lab’s previous work, gender-based disparities in head impact responses were highlighted, with small females experiencing higher injury risk metrics, despite lower skull von Mises stress. Beyond small females, children of various ages and their head responses during impacts were also analyzed. In addition to the previously developed quadcopter drone model, a new Mavic Pro drone model was developed, and this model was integrated with human head …

Impinging Jet Flow And Hydraulic Jump Of Newtonian And Viscoplastic Liquids, Wenxi Wang

Electronic Thesis and Dissertation Repository

The steady laminar incompressible flow of an axisymmetric impinging jet of either a Newtonian fluid or a viscoplastic fluid of the Heschel-Bulkley type and the hydraulic jump of either a circular or polygonal shape on a solid disk is analyzed. The polygonal jump is induced by azimuthal dependence edge conditions: a non-circular disk or a circular disk with a variable edge film thickness. The thin-film and Kármán–Pohlhausen approaches are utilized as theoretical tools.

To cross the jump smoothly, a composite mean-field thin-film approach is proposed. The stress singularity for a film freely draining at the disk edge is found to …

Evaluating Eeg–Emg Fusion-Based Classification As A Method For Improving Control Of Wearable Robotic Devices For Upper-Limb Rehabilitation, Jacob G. Tryon

Electronic Thesis and Dissertation Repository

Musculoskeletal disorders are the biggest cause of disability worldwide, and wearable mechatronic rehabilitation devices have been proposed for treatment. However, before widespread adoption, improvements in user control and system adaptability are required. User intention should be detected intuitively, and user-induced changes in system dynamics should be unobtrusively identified and corrected. Developments often focus on model-dependent nonlinear control theory, which is challenging to implement for wearable devices.

One alternative is to incorporate bioelectrical signal-based machine learning into the system, allowing for simpler controller designs to be augmented by supplemental brain (electroencephalography/EEG) and muscle (electromyography/EMG) information. To extract user intention better, sensor …

Numerical Modeling And Simulation On Deformation And Failure Behaviors Of Polymeric Materials, Heng Feng

Electronic Thesis and Dissertation Repository

Featured by biocompatibility, high compliance and capacity in sustaining large deformation, dielectric elastomers (DEs) and hydrogels have gained extensive research popularity for their potential applications in the fields of soft robots, biomimetics, tissue engineering, drug delivery, and energy harvesting. The design of such soft and smart material-based devices and structures requires deep understanding and accurate simulation of their constitutive behaviors, which is challenged by their nonlinear material properties due to unique microstructures and multi-physics coupling. Meanwhile, in different application contexts, those structures are also susceptible to different failure modes, imposing further challenges in simulating and predicting their performance. To fulfill …

Experimental Investigation Of The Phase Change Process Within Circular Geometries, Kyle Teather

Electronic Thesis and Dissertation Repository

Latent heat thermal energy storage systems have many advantages over sensible-heat-based thermal storage systems, such as an increased energy density with a narrower range of operating temperatures. The main barrier to implementing latent heat storage systems is the low thermal conductivity of typical storage materials, called phase change materials (PCMs). Furthermore, the heat transfer mode in the liquid phase is natural convection, which is influenced by the geometry and orientation of the heat source and sink, thus impacting the phase change pattern and heat transfer. It is critical to have a good understanding of the underlying fundamental physics over the …

Mechanical Response Of The Craniofacial Skeleton To Subfracture Impacts In The Time And Frequency Domains, Paige Merko

Electronic Thesis and Dissertation Repository

Resonant frequencies have been suggested as a mechanism of brain injury since these vibrations can transfer energy into the brain. Study of the vibrational response of the craniofacial skeleton to impact is limited in literature. In this research, four cadaver specimens were impacted at five locations on the craniofacial skeleton. The mechanical response to each impact was compared in the time and frequency domains. Impacts to the maxilla and its associated soft tissues tended to be attenuated, while impacts to the cranial vault, specifically to the occipital, produced the most severe response. Results suggest that the facial skeleton and its …

Using Statistics, Computational Modelling And Artificial Intelligence Methods To Study And Strengthen The Link Between Kinematic Impacts And Mtbis, Andrew Luke Mcconnell Patterson

Electronic Thesis and Dissertation Repository

Mild traumatic brain injuries (mTBIs) are frequently occurring, yet poorly understood, injuries in sports (e.g., ice hockey) and other physical recreation activities where head impacts occur. Helmets are essential pieces of equipment used to protect participants’ heads from mTBIs. Evaluating the performance of helmets to prevent mTBIs using simulations on anatomically accurate computational head finite element models is critically important for advancing the development of safer helmets. Advancing the level of detail in, and access to, such models, and their continued validation through state-of-the-art brain imaging methods and traditional head injury assessment procedures, is also essential to improve safety. The …

Development Of A Computationally Efficient Method For Modelling Thermal Energy Storage In Packed Beds Of Spherically Encapsulated Phase Change Material, Colin Jaffray

Electronic Thesis and Dissertation Repository

A novel computationally efficient method for modelling melting and solidification processes in packed beds of PCM encapsulated spheres is introduced. The proposed method involves the full discretization of only one centrally located sphere to fully simulate the phase change process, while treating all other spheres in the packed bed as voids with boundary conditions derived from the simulated sphere. At each time step, the computed heat transfer parameters on the exterior surface of the simulated sphere undergoing the phase change process are extracted, and imposed as boundary conditions on surrounding spheres. The proposed method results in a significant reduction in …

Diffusion-Dependent Electrodes For All-Solid-State Lithium-Ion Batteries, Peiman Mardani

Electronic Thesis and Dissertation Repository

Electrode design, which is closely related to electronic and ionic transport, has a significant impact on all-solid-state batteries' performance. Typically, a combination of the active material and solid electrolyte serves as the electrode for all-solid-state batteries. An effective scaling technique to spatially organize the two components is essential for high-performance all-solid-state batteries. Here, an electrode design for all-solid-state batteries is given with a higher energy density than the typical composite-type electrode. The first section of the thesis presents a simple electrode design that primarily consists of blended active materials of graphite and phosphorus to meet the demands of all-solid-state batteries …

Quantification Of Flows Emerging From Small Pores In Plane Walls, Matia Peter Edwards

Electronic Thesis and Dissertation Repository

Current membrane separation processes are limited in high production and high purity settings due to a trade-off between selectivity and permeance. Methods of creating nanoscale geometries in 2D materials are emerging and present an opportunity for fast, size selective mass transport that can be tailored to a wide array of applications. This thesis develops a method for quantifying flow through small pores in plane walls based on the behaviour of a solute dispersed in a downstream reservoir. This method is validated for a range of micropore diameters, for which flow rates can be calculated with confidence, and is shown to …

Pressure Drop And Heat Transfer In Flow Over An Array Of Blocks Of Varying Heights: A Statistical And Ai Analysis On The Effect Of Block Height Variation, Ali Navidi

Electronic Thesis and Dissertation Repository

The presence of a stiff obstruction in the path of fluid causes the creation of a boundary layer over and around the obstruction. The flow over an idealized, two-dimensional series of blocks is numerically investigated to determine how statistical blocks height variation, such as standard deviation, mean, and skewness, influence pressure drop and heat flux. These data sets serve as a foundation for developing models for estimating the heat transfer coefficient of each block using machine learning (ML) methods. The results show that the pressure drop increased by 60% when the standard deviation of heights of blocks increased from 0.1 …

A Numerical Method For Studying The Effectiveness Of Polyurethane Foam As Personal Protective Equipment Material, Lamia Tahsin Aroni

Electronic Thesis and Dissertation Repository

This thesis documents the characterization of flexible polyurethane foam (FPF) to be used as a personal protective equipment material. Polyurethane samples were tested experimentally to calculate the physical properties which were later re-created using a numerical model. A discrete element modeling software was used to generate the geometry to mimic the physical properties of FPF. The pore level numerical model was used to calculate the possible rate of particle penetration for a range (0.2 -200) µm of particle sizes. A parametric study was done using the polyurethane foam parameters to understand the breathing dynamics under steady conditions. The possible particle …

A Framework For Stable Robot-Environment Interaction Based On The Generalized Scattering Transformation, Kanstantsin Pachkouski

Electronic Thesis and Dissertation Repository

This thesis deals with development and experimental evaluation of control algorithms for stabilization of robot-environment interaction based on the conic systems formalism and scattering transformation techniques. A framework for stable robot-environment interaction is presented and evaluated on a real physical system. The proposed algorithm fundamentally generalizes the conventional passivity-based approaches to the coupled stability problem. In particular, it allows for stabilization of not necessarily passive robot-environment interaction. The framework is based on the recently developed non-planar conic systems formalism and generalized scattering-based stabilization methods. A comprehensive theoretical background on the scattering transformation techniques, planar and non-planar conic systems is presented. …

Development Of A Two-Axis Cyclic Loading Device For Mechanical Testing Of Glenoid Component Fixation, Cintya Tavares

Electronic Thesis and Dissertation Repository

The fundamental mechanism of aseptic glenoid component loosening, the rocking horse phenomenon, is a reaction to glenohumeral articular forces that are not centered on the component. While glenoid component loosening remains a problem, the underlying mechanisms that lead to fixation failure at the bone-component contact remain controversial. Several studies employing the ASTM F2028 technique have successfully recreated the rocking horse effect. However, no obvious strategy to decrease component loosening has been presented. This thesis investigates the behavior of forces that lead to component loosening on cyclically loaded components using three different protocols and testing apparatuses—a Stewart Platform, a cyclic loading …

Numerical Investigation Of Flow And Thermal Behavior In Channels With Pcm-Filled Thermal Energy Storage Columns For Potential Application In Photobioreactors, Sameed Akber

Electronic Thesis and Dissertation Repository

Microalgae has been identified as a potential source in the production of biofuel. Photobioreactors, which are used for microalgae production, normally experience temperature variations over the diurnal cycle due to changes in ambient conditions. The thermal regulation of photobioreactors to minimize temperature variations will result in a higher yield of microalgae, which are sensitive to such variations. The present research is aimed to investigate a novel approach to thermally regulate photobioreactors using phase change materials (PCM) where the latent heat of the material is exploited as the energy storage. The present research uses a numerical approach to study the flow …

The Design And Evaluation Of A Subacromial Implant In Restoring Normal Glenohumeral Joint Stability In The Presence Of A Massive Irreparable Rotator Cuff Tear, Cole T. Fleet

Electronic Thesis and Dissertation Repository

Massive irreparable rotator cuff tears are a common cause of pain and disability. Several different treatment options are available for this pathology; however, these treatments have been associated with poor clinical outcomes when used to treat younger (<65 years), more active patients. The purpose of this thesis was to design and evaluate a subacromial implant in its ability to restore normal glenohumeral stability and range of motion. The implant was created as a modular device, which captured different implant thicknesses (5mm and 8mm) and constraints (high and low) within its design. In-vitro testing compared the ability of these implants to restore normal shoulder biomechanics. The results indicated the 5mm high constraint implant to be the most effective in restoring normal joint position. Furthermore, range of motion increased when the implant was paired with a tuberoplasty procedure. These results suggest this implant may be advantageous in treating younger patients.

Numerical Analysis Of Internal Hydraulic Jump In Complex Topography, Dylan Macriner

Electronic Thesis and Dissertation Repository

Topographic effects on internal hydraulic jumps in stratified flow over complex geometry are studied. The simulations are motivated by flow conditions present in a channel in Hood Canal, Washington with continuous density profiles and constant inlet velocities.

Results show that mixing in the domain is typically increased by topographic variation, where isolated expansions saw an increase in mixing, but the associated velocity decrease in expansions had contrasting effects on mixing. Likewise, a contraction with an increased velocity caused more mixing, seeing geometry change and velocity acting as compounding factors. 2D results including along channel topographic variation modelled after Hood Canal's …

Comparison Of Layered Nickel Cobalt Manganese Oxide Cathodes With Different Compositions And Morphologies In Lithium-Ion Batteries, Fanny Poon

Electronic Thesis and Dissertation Repository

The revolutionary rechargeable lithium-ion battery paves the way for environmentally-friendly applications such as electric vehicles. Nevertheless, further improvements are required to match or exceed the performance of conventional internal combustion engine vehicles, such as higher energy density, faster charging speed, longer lifetime, better safety and lower cost. Lithium layered nickel cobalt manganese oxides (NCM) are a popular choice of cathode material, but they still suffer from problems such as cation mixing, volume changes, microcracking, surface side reactions, high temperature performance issues and structural reconstruction. This thesis compares various NCM materials to figure out what guidelines should be followed to improve …

Motion And Crosslinked Polyethylene Wear In Reverse Total Shoulder Arthroplasty, Christopher Millward

Electronic Thesis and Dissertation Repository

The reverse total shoulder arthroplasty (RTSA) has quickly grown to become the most commonly used shoulder arthroplasty design; however, reports have shown evidence of RTSA failures related to polyethylene wear and damage. Therefore, the present work investigated the wear of crosslinked polyethylene (XLPE) in environments similar to that of an in vivo RTSA. Additionally, a computational model was developed based on a previous study of the shoulder motions obtained from a selection of typical patients with RTSA. This model quantified the amount of glenohumeral motion that an RTSA may be subjected to in vivo and provided an approximate value for …

To Develop A Clinically Friendly Multi-Segment Kinematic And Kinetic Foot Model And Test It On Pre-/Post-Hto Patients With Medial Knee Osteoarthritis And Knee Varus, Songlin Zhu

Electronic Thesis and Dissertation Repository

This study aims to develop a clinically useful multi-segment foot model that will enable the analysis of foot kinematics and kinetics in an optical motion capture laboratory setting. This study will also test the new multi-segment foot model on patients with knee osteoarthritis and varus knee alignment that is corrected by high tibial osteotomy (HTO). The multi-segment foot model divides the foot into four functional segments: the hindfoot, midfoot, forefoot and hallux. An X-Z-Y-Cardan angle rotation convention was used to determine intersegmental dorsi/plantar flexion, inversion/eversion, and internal/external rotation. Joint moments, joint powers and medio-longitudinal arch (MLA) height/length ratio were also …

Computational Modelling Of Resin Infiltration And Curing In High Pressure Resin Transfer Molding, Anthony Paul Rexford Sherratt

Electronic Thesis and Dissertation Repository

Increased pressure on automotive manufactures to reduce overall greenhouse gas emissions from their vehicles has driven research into replacing conventional steel components with carbon fiber reinforced plastics (CFRP). This is due to their high weight specific properties and design freedom. High pressure resin transfer molding (HP-RTM), a derivative of resin transfer molding, is a manufacturing process for CFRP’s that offers high automation potential and low cycle times; critical properties of a manufacturing process for the automotive sector.

The goal of the present work is to increase the accuracy and reduce the computational overhead of current RTM infiltration and curing models. …