Engineering Commons^™

Changes In Balance With Brain Inflammation: Sensitivity In Dual Motor Mechanisms, Hannah Mcdade

Electronic Theses and Dissertations

Concussion assessment in athletes has gained prominence due to potential long-term consequences of traumatic brain injuries. Evaluating balance alterations is crucial for understanding post-injury motor control strategies. This study introduces a novel approach to understanding center of pressure (COP) dynamics during quiet stance tasks for assessing balance impairments in athletes recovering from concussion. Concussed athletes often experience impaired motor function and cognitive deficits, increasing the risk of orthopedic injury. Traditional balance assessments focus on total COP (COPt), overlooking nuanced hip and ankle mechanisms. This research investigates COP variations between constant loading (COPc) and variable loading (COPv) signals in concussed athletes …

Quantitative, Photocurrent Multidimensional Coherent Spectroscopy, Adam Halaoui

Electronic Theses and Dissertations

Multidimensional coherent spectroscopy (MDCS) is a quickly growing field that has a lot of advantages over more conventional forms of spectroscopy. These advantages all come from the fact that MDCS allows us to get time resolved correlated emission and absorption spectra using very precisely chosen interactions between the density matrix and the excitation laser. MDCS spectra gives the researcher a lot of information that can be extracted purely through qualitative analysis. This is possible because state couplings are entirely separated on the spectra, and once we know how to read the data, we can see how carriers transport in the …

Kinematic Analysis Of Gait And Deep Knee Flexion For Pre- And Post-Operative Total Knee Arthroplasty, Samantha Collins

Electronic Theses and Dissertations

Osteoarthritis (OA) is a form of arthritis that develops in the joint due to overuse and aging causing pain, discomfort, and disability. Total Knee Arthroplasty (TKA) is a surgical procedure performed when OA symptoms are severe with an estimated 600,000 patients in the United States currently receiving TKA. Studies have reported dissatisfaction of the knee for 14-39% of patients. This study collected knee kinematics before and after surgery using stereo radiography for precise measurement of gait and deep knee flexion activities. Results showed healthy knee kinematics were not restored and no significant changes could be seen from OA kinematics in …

Computational Methodology For Generating Patient-Specific Soft Tissue Representations, Ahilan Anantha Krishnan

Electronic Theses and Dissertations

This dissertation focused on modeling specimen-specific soft tissue structures in the context of joint replacement surgery. The research addressed four key aspects. The first study involved developing a workflow for creating finite element models of the hip capsule to replicate its torque-rotational response. Experimental data from ten cadaveric hips were used to calibrate the models, resulting in improved accuracy and relevance for surgical planning and implant design. The second study tackled the challenge of expediting the calibration of mechanical properties of the hip capsule to match patient-specific laxities. A statistical shape function model was proposed to generate patient-specific finite element …

Digital Twins Of The Living Knee: From Measurements To Model, Thor Erik Andreassen

Electronic Theses and Dissertations

Modern medicine has dramatically improved the lives of many. In orthopaedics, robotic surgery has given clinicians superior accuracy when performing interventions over conventional methods. Nevertheless, while these and many other methods are available to ensure treatments are performed successfully, far fewer methods exist to predict the proper treatment option for a given person. Clinicians are forced to categorize individuals, choosing the best treatment on “average.” However, many individuals differ significantly from the “average” person, for which many of these treatments are designed. Going forward, a method of testing, evaluating, and predicting different treatment options' short- and long-term effects on an …

Exploration Of Motion Capture System To Investigate Human Shoulder Kinematics, Ola Alsaadi

Electronic Theses and Dissertations

The glenohumeral joint (GH) is commonly conceptualized as a ball-and-socket joint [1], and its center of rotation (COR) is presumed to coincide with the geometric center of the medial-superior region of the humeral head [2]. Recent research has endorsed improvements in COR estimation through invasive and noninvasive techniques, including cadaver studies, stereophotogrammetry, and motion capture (MOCAP) systems. Despite increased interest in wearable technology within human movement analysis, the problem of COR estimation employing MOCAP systems and its validation against bi-planar fluoroscopy remains relatively unexplored.

This study employed a marker-based MOCAP system to compare the accuracy, error, and precision of three …

Anisotropic Mechanical Material Investigation On Moisture And Strain Rate Sensitivity Of Direct Compounded Compression Moulded Glass/Pa6 Lfts, Pouya Mohammadkhani

Electronic Theses and Dissertations

In this study the tensile properties at different loading rates as well as shear properties of a direct-compounded compression-moulded Polyamide6 (PA6)/glass long fibre thermoplastic (LFT-D) material with a fibre weight content of 30% were investigated. The effects of moisture on the anisotropic mechanical and material properties of Glass/PA6 LFT materials were examined by testing at four different material directions of 0°, +45°, ˗45°, and 90°. In order to study the effect of tensile loading rate on this material, different nominal strain rates ranging from 0.0001 1/s to 150 1/s were examined. Under quasi-static loading, at a 2% moisture content, the …

Enhancing Breast Cancer Detection Through Combination Of Contrastive Learning And Adversarial Domain Adaptation, Mahnoosh Torabi

Electronic Theses and Dissertations

The most common cancer diagnosed worldwide is breast cancer and early detection is essential for reducing mortality. The best standard for early detection of breast cancer is digital mammography, which can aid physicians in treating the illness when it is still curable. However, inaccurate mammography diagnoses are frequent and can cause patients to undergo unnecessary examinations and therapies. This study aims to explore deep-learning techniques that can be utilized to implement and train a model to identify breast cancer cases in mammograms. Current deep learning-based diagnostic techniques are hindered by two fundamental issues: the expensive and time-consuming task of data …

Residual Stress In Metal Additive Manufacturing Of Thin-Walled Components: Investigation And Development Of Prediction Models With Respect To Path Planning, Bita Mohajernia

Electronic Theses and Dissertations

This dissertation focuses on the investigation of residual stress in metal additive manufacturing of thin-walled components. Residual stress is a critical issue in additive manufacturing processes as it can lead to structural deformations, reduced mechanical properties, and potential failure of the manufactured parts. The objective of this research is to develop a fast and accurate prediction model for residual stress using numerical and machine learning techniques, with a specific focus on path planning. To achieve the research objectives, the dissertation employs numerical simulations to understand the underlying physics and mechanics of residual stress formation in the additive manufacturing process. These …

Variability Of Noise Exposure Forecast Outputs Due To The Selection Of Input Parameters, Junxian Zhao

Electronic Theses and Dissertations

The growth of civil aviation and the resulting aircraft noise exposure and noise annoyance have become a serious environmental issue for residents living around airports. Land use planning and management is one method to mitigate noise and annoyance. It is one of four components of the Balanced Approach to Aircraft Noise Management adopted by International Civil Aviation Organization (ICAO). Effective land use and planning tries to remove conflicts between noise and residential communities by keeping noise sensitive functions away from levels of predicted high noise exposure. Authorities typically use noise contours to determine noise exposure around airports. Noise thresholds are …

Digital Realization Of Spiking Neural Network, Mahsasadat Seyedbarhagh

Electronic Theses and Dissertations

Spiking Neural Network which is known as the third generation of artificial neural networks can imitate the same biological patterns of human brain. Neuromorphic Computing is a multidisciplinary research topic which employs digital and analog platforms to implement bio-inspired systems and is able to operate parallelly with low-power consumption. This research study presents the digital design for several bio-inspired systems such as biophysical spiking neuron, calcium signaling astrocyte, and a neuron-astrocyte interaction models using various approximation methodologies. Astrocytes have an essential impact within the neural network and their role is to maintain support for neuron, control the ion hemostasis and …

A Reinforcement Learning Algorithm For Training A Spiking Neural Network Agent, Seyede Narjes Zamani

Electronic Theses and Dissertations

Over the past two decades, Spiking Neural Networks (SNNs), as the third generation of Artificial Neural Networks, have gained widespread use due to their ability to closely mimic human brain neuron behavior. Being spike-based and resembling biological neurons, SNNs have demonstrated superior energy efficiency compared to conventional counterparts. However, to fully harness their potential, effective training methods are essential. Despite significant progress in the field of biological implementation of SNNs, there remains a need for research to identify the most optimal learning approach. To address this, we employed Policy-based stochastic reinforcement learning to train a spiking neural network using Izhikevich …

New Memristive Architecture For Digital Circuits Design, Farzad Mozafari

Electronic Theses and Dissertations

Before 1971, all the electronics were based on three basic circuit elements. Until a professor from UC Berkeley reasoned that another basic circuit element exists, which he called memristor; characterized by the relationship between the charge and the flux-linkage. A memristor is essentially a resistor with memory. The resistance of a memristor (Memristance) depends on the amount of current that is passing through the device. In 2008, a research group at HP Labs succeeded to build an actual physical memristor. HP's memristor was a nanometer scale titanium dioxide thin film, composed of two doped and undoped regions, sandwiched between two …

Mitigation Of Asymmetrical Currents In Permanent Magnet Synchronous Machine With Unbalanced Stator Winding Impedance For Electric Vehicle Application, Khagendra Thapa

Electronic Theses and Dissertations

The electric drive system of a permanent magnet synchronous machine (PMSM) with stator winding impedance asymmetry draws unbalanced three-phase stator currents if the conventional current control scheme is employed. Due to these asymmetrical stator currents, some issues such as uneven heating of the inverter phases and switches, additional losses in the motor due to skin and proximity effects, vibration and noise, uneven heating of the motor phases, and torque ripple appear in the PMSM drive. These effects reduce the reliability, efficiency, and lifespan of the machine. The conventional proportional-integral (PI) current controller in a PMSM drive is unable to mitigate …

Prediction And Management Of Aircraft Noise Annoyance Around Canadian Airports, Julia Georgieva Jovanovic

Electronic Theses and Dissertations

Noise pollution is a serious environmental problem affecting millions of people world-wide. Aircraft are one source of transportation noise that impacts residents in communities surrounding airports and flight paths. Noise is the biggest nuisance of airport operations and has resulted in complaints, protests, and even legal action. The burden of noise is likely to increase in the coming decades as quieter aircraft technologies lag traffic growth projections, and rapid urbanization narrows the buffer between airports and residential areas. Numerous physical and psychological effects of aircraft noise exposure have been studied, the most common of which is annoyance. Noise annoyance has …

Microstructure, Mechanical Properties And Electrical Conductivities Of As-Cast Al-0.3mn Alloy, Wutian Shen

Electronic Theses and Dissertations

Al-0.3Mn was prepared by permanent steel mold casting (PMSC) with three different section thicknesses of 6, 10, 20 mm, and also by squeeze casting (SC) with a cross-sectional thickness of 20 mm under an applied pressure of 90 MPa. The first group of samples was employed to investigate the difference in mechanical and electrical properties between the PSMC Al-0.3Mn Alloy and high-purity (HP) Al (99.9%). The results of tensile testing indicated that the ultimate tensile strength (UTS), yield strength (YS) of the cast HP Al significantly increased to 72.3 and 20.4 MPa from 59.2 and 14.0 MPa. However, the elongation …

Exploring The Use Of Audible Sound In Bone Density Diagnostic Devices, Evan J. Bess

Electronic Theses and Dissertations

Osteoporosis is a medical condition in which there is a progressive degradation of bone tissue that correlates with a characteristic decrease in bone density (BD). It is estimated that osteoporosis affects over 200 million people globally and is responsible for 8.9 million fractures annually. Populations at risk for developing osteoporosis include post-menopausal women, diabetic patients, and the elderly, representing a large population within the state of Maine. Current densitometric and sonometric devices used to monitor BD include quantitative computed tomography (QCT), dual-energy x-ray absorption (DXA), and ultrasound (QUS). All methods are expensive and, in the cases of QCT and DXA, …

Wave Attenuation Through Submerged Oyster Aquaculture Cages, Liam T. Hanley

Electronic Theses and Dissertations

Coastal erosion presents a growing issue to shorelines around the world and is especially harmful to Maine, a region where sea-level rise is higher than the global average. Green and hybrid coastal defense strategies are being implemented around the country to provide sustainable, habitat-friendly solutions to erosion control. Maine is a hotspot for commercial aquaculture, with an estimated $13.6 million economic impact. This study looks to bridge the gap between Maine aquaculture and the living shorelines initiative, by determining the wave attenuating properties of submerged oyster cages. The project will be able to inform local oyster farmers, resource planners, and …

Characterization Of Mammographic Dense Tissue Sub-Types Using Classification Algorithms On Metric Space Technique Output Functions, Madison Raza

Electronic Theses and Dissertations

In recent years breast cancer has become the leading cause of global cancer incidence. One of the most common forms of screening is through the use of digital x-ray screening mammography. Risk assessment models which help predict a patient’s risk of developing breast cancer rely mainly on patient history and qualitative breast density assessment from screening. The 2D wavelet transform maxima modulus (2D WTMM) method uses a sliding window approach to quantify the spatial organization of underlying mammographic tissue according to Hurst- exponent ranges (H) as fatty (H ≤ 0.45), healthy dense (H ≥ 0.55) and …

Impact Of Solar Generation On Ieee 9-Bus System, Tasnim Ikra Rahman

Electronic Theses and Dissertations

There has been an increasing interest in renewable energies due to public awareness of the negative effects of fossil fuel-fired electricity generation on the environment, and policies have been enacted requiring progressive reduction of such generation. Due to some favorable characteristics of solar over other renewables, solar power has grown considerably. Integration of solar generation into the existing power grids poses significant challenges. Solar generators' limited reactive power capability can cause several problems, such as significant voltage drops or rises in the system. Therefore, voltage stability is a major concern. This thesis presents an investigation of the voltage characteristics of …

Development And Characterization Of Shear Thinning Cnf-Tempo Hydrogels For Use In Aquaculture Vaccines, Jacob A. Holbrook

Electronic Theses and Dissertations

Aquaculture has shown significant growth within the past few decades and is expected to continue expanding rapidly as the global demand for fish consumption continues to increase. A significant loss within the aquaculture industry is due to pathogen transmission within the farm systems. These pathogens are mitigated through various methods that are not cost effective or have limited protection. The most common method of pathogen mitigation is through oil-based injection vaccines as they provide even protection across vaccinated fish and provides the longest protection compared to other vaccination methods. These oil-based injection vaccines are not without their flaws as they …

Accessible Autonomy: Exploring Inclusive Autonomous Vehicle Design And Interaction For People Who Are Blind And Visually Impaired, Paul D. S. Fink

Electronic Theses and Dissertations

Autonomous vehicles are poised to revolutionize independent travel for millions of people experiencing transportation-limiting visual impairments worldwide. However, the current trajectory of automotive technology is rife with roadblocks to accessible interaction and inclusion for this demographic. Inaccessible (visually dependent) interfaces and lack of information access throughout the trip are surmountable, yet nevertheless critical barriers to this potentially lifechanging technology. To address these challenges, the programmatic dissertation research presented here includes ten studies, three published papers, and three submitted papers in high impact outlets that together address accessibility across the complete trip of transportation. The first paper began with a thorough …

Investigating The Effect Of Bead Geometry On Fiber Orientation And Thermomechanical Properties For Large-Format Extrusion-Based Additive Manufacturing, Joanna F. Keaton

Electronic Theses and Dissertations

In large-format extrusion-based additive manufacturing of polymer composites, the relationship between material properties and processing parameters requires further investigation. This thesis focuses on the relationship between fiber orientation and thermomechanical properties for short fiber-filled thermoplastic polymer systems manufactured by extrusion-based additive manufacturing. Fiber orientation is particularly important in determining the thermomechanical properties of the composite material as properties in the direction of deposition are expected to be higher for highly aligned fibers than randomly aligned fibers. Fiber orientation distribution, which is related to processing parameters and deposition conditions, can be efficiently represented by the orientation tensor. The orientation tensor can …

Longitudinal Case-Control Study Of Mammographic Breast Tissue Subtypes, Kendra Batchelder

Electronic Theses and Dissertations

Breast density is a known risk factor for breast cancer. However, there has been limited research on potential subtypes of mammographic dense breast tissue to identify areas of active dense tissue that is structurally reorganizing and links to cancer dynamics, versus areas of passive dense tissue which remains organized. We hypothesize that the amounts of subtypes of mammographic dense tissue and the associated rate of change through time could provide insights into breast cancer risk. A retrospective study was conducted to investigate breast cancer using longitudinal screening mammograms and accompanying pathology reports collected in 2015. Patients were matched by age …

Measuring Of Thermal Conductivity And Heat Capacity Of Different Papers And Heat-Sealing Process Of Papers With A Polymer Layer, Amenah Khalaf

Electronic Theses and Dissertations

Packaging is an important and safe way to protect our food and other things through transportation, but the use of plastic based packaging is causing issues with plastic pollution. To replace plastic packaging with a paper-based option that has a barrier coating, good heat sealing will be needed to be a drop-in replacement. While much as been studied on the heat sealing of polymer layers, little has been reported around the heat sealing of paper that has a polymeric barrier coating.

Experiments were conducted to characterize the thermal conductivity and heat capacity of paper as a function of press pressure …

The Performance Analysis And Optimization Of Wave Energy Converters From Modeling To Basin Testing, Lauren Dickson

Electronic Theses and Dissertations

The successful development and optimization of wave energy converters (WECs) are pivotal to the pursuit of sustainable and renewable energy sources. This thesis explores the elements in a workflow that develops and demonstrates the protocols for the optimization of WECs using a rapid design\build\test procedure. This thesis establishes the characterization of scaled ocean test sites, develops the performance metrics, generates the performance modeling techniques to predict the optimum design geometries which will be produced for final testing, and finally, establishes the basin test plan which will be used to conduct the testing on the optimum design. The findings of this …

Mechanical Characterization Of Automated Fiber Placement And Additive Manufacturing Hybrid Composites, Lucan Haviland

Electronic Theses and Dissertations

This thesis presents the optimization of processing parameters based on the mechanical properties of Continuous Fiber-Reinforced Thermoplastic (CFRTP) Unidirectional (UD) consolidated tapes. The UD tapes were consolidated using an AFP head and a thermoforming press for comparison. The adhesive strength of hybrid parts consisting of CFRTP UD tape bonded to a 3D-printed substrate with the same matrix system were investigated. Large Area Additive Manufacturing (LAAM) was utilized for the 3D-printed parts. Different types of thermoplastic composite materials were explored, including Glass Fiber reinforced Polyethylene Terephthalate Glycol (GF/PETG), Carbon Fiber reinforced Polyethylene Terephthalate Glycol (CF/PETG), Carbon Fiber reinforced Polycarbonate (CF/PC), and …

Use Of Photo Isomers To Enhance The Removal Of Lignin From Woody Biomass Hydrolysate, Dipesh J. Karki

Electronic Theses and Dissertations

In this investigation we propose a novel method to enable precipitation of desired solutes using photo-isomers in the extraction solvent. This photo-switchable solvent would enable dissolution or precipitation of desired components using alternating UV or visible light to modify the solubility of the compounds of interest. Three photo-isomers namely native azobenzene, diethoxy azobenzene and diethylamino azobenzene were studied in three different organic solvents: medium chain length alcohol, ethanol and acetone. It was found that among the different combinations of solvent and photo-isomer, acetone and the 4,4’-diethoxy azobenzene solution was most efficient at precipitating dissolved lignin in response to UV light …

Designing And Modeling A Fail-Safe Mechanism To Be Used In Attachment Of A Transcutaneous Femoral Implant To A Prosthetic Device, Emma Sperry

Electronic Theses and Dissertations

Amputations are quite common and even modern prosthetic devices are plagued by problems. There are approximately 2 million people living with limb loss in the U.S. and on average 185,000 amputations occur yearly. Common attachment mechanisms for external prosthetic components to a residual limb, that is, sockets, pose numerous challenges. Issues include skin irritation, discomfort, socket fit issues, and immobility. Issues include skin irritation, discomfort, socket fit issues, and immobility. Transcutaneous implants have great potential as a connection method for external prosthetic components to a residual limb but because the implants are typically solid, they correlate to extremely high infection …

Nanocellulose Based Foams For Low-Cost Disposable Medical Applications, Dominic Kugell

Electronic Theses and Dissertations

Polyurethane foams have been a staple material for their use in medical positioners, such as post-surgery elevation pillows as well as specific tailored positioners for their use during surgery. Polyurethane foams are preferred because of their lower cost compared to other petroleum derived foams, their versatility, and suitable mechanical properties. However, the environmental impact, including both cost and perception, of these foams is immense. Therefore, alternatives are being explored with biopolymers emerging as a promising class of materials. Cellulose is one such polymer that has recently demonstrated desirable properties. In this study, cellulose nanofibrils (CNF), a household foaming agent, and …