Mechanical Engineering Commons^™

Additive Manufacturing Of Multifunctional Materials And Composites, John Michael Pappas

Doctoral Dissertations

"This research focused on developing fundamental knowledge of process-material interactions for additive manufacturing of multifunctional materials that are highly desirable in high-tech industries for potential weight and space savings. Multifunctional materials are very sensitive to defects, which severely hinder performance. Thus, defect formation was systematically studied to develop strategies and methodologies to efficiently fabricate high-performance materials and composites. Blown-powder-based laser additive manufacturing of transparent spinel ceramics was investigated to reduce porosity and cracking, defects that hindered transparency and mechanical properties. A systematic study of processing parameters revealed that laser power and powder flow rate had the largest effects on defect …

Nano-Micro Engineering For Advanced Energy Devices, Tazdik Patwary Plateau

Doctoral Dissertations

The development of advanced materials and manufacturing techniques for energy storage devices is continuously growing. The research emphasizes micro-engineering, nano-engineering, and advanced materials science, with the goal of enhancing the performance and scalability of manufacturing methods of different materials processing with a view of achieving sustainability. In the micro-engineering domain, novel methods for fabricating thick electrodes with short diffusion paths are introduced, enabling higher mass loading and improved battery performance. Additionally, innovative strategies for optimizing the performance of carbon nanofibers (CNFs) as anode materials in LIBs are explored in the nano-engineering domain. These studies address key challenges such as inter-bonding …

A Study Exploring The Use Of Artificial Ligaments To Enhance The Human-Robot Interface Via Force Distribution Manipulation In Biomimetic Cuff Systems, Adifet Cejovic

Dissertations and Theses

Comfort is among the main priorities when designing a wearable assistive device that needs to be used for long sessions. There is a growing need for wearable systems that provide aid to patients with an injured knee. In addition, there has been an effort to incorporate cable-driven designs rather than rigid attachments. This change in design decreases the overall weight of the system and can allow the cable to adapt to a user’s change in gait patterns. This thesis investigates a cuff system centered around the knee and the design of a testing rig. This system incorporates elements from pre-existing …

Design And Lab Implementation Of An Air Source Transcritical Co2 Heat Pump, Geoffrey Turbeville

Dissertations and Theses

A laboratory-scale air-source transcritical CO2 heat pump (TCHP) was developed to evaluate the performance of low-global-warming-potential (GWP) refrigerants for cold climate applications. A custom climate chamber was also constructed to simulate winter weather conditions typical of the northeastern United States. Both the TCHP and the chamber were fully instrumented to collect temperature, pressure, and mass flow data, which were used to calculate the co- efficient of performance (COP) in accordance with ASHRAE standard refrigerant enthalpy methods. Prior to testing the CO2 system, the experimental setup was benchmarked using a commercially available R410A heat pump manufactured by LG.

The climate chamber …

Experimental And Analytical Investigation Of Particle Dynamics In Newtonian And Non-Newtonian Fluids In A Taylor-Couette Cell, Andres F. Velez Mendoza

Dissertations and Theses

This doctoral dissertation investigates heavy particle sedimentation in Newtonian and non-Newtonian fluids, aiming to understand their behavior in Drilling Fluid (DF) systems used in oil and gas industry, where such phenomenon can lead to operational issues such as lost circulation, well control problems, and even blowouts. To simulate DF dynamics under operational conditions, this study utilizes a Taylor-Couette (TC) cell, which consists of a rotating inner cylinder and a stationary outer cylinder separated by a 9.0 mm annular gap. The TC cell allows for the investigation of the sedimentation behavior of spherical particles within both Newtonian fluids (deionized water and …

Ranking Of Non-Destructive Testing Methods For Ductile Iron Castings For Industry 4.0, Michael W. Jones

College of Graduate Studies: Theses & Dissertations

Non-destructive testing techniques provide a unique solution to provide quality assurance of parts rapidly and efficiently without altering the functional properties of the workpiece. The metal casting industry requires an elevated level of quality assurance, as castings are critical components to several industries. The wrong selection of non-destructive testing methods could increase production costs, quality costs, and potentially permit non-conforming castings to enter the market. The aim of this research is to develop a ranking model for non-destructive testing techniques for ductile iron castings within the context of the fourth industrial revolution. The ranking model analyzes the effectiveness of the …

A Generalized Coherence Framework For Quantifying Input Contributions In Multi-Input Systems With Correlated Or Uncorrelated Inputs, Nolan H. Howes, Matthew S. Allen, Dario Farina, Steven Knight Charles

Faculty Publications

In multi-input systems, it is often necessary to quantify the contribution of each input to an output. Such contribution analysis is frequently performed using coherence. However, when correlation is present between inputs, existing coherence measures do not accurately quantify the contribution of individual inputs, except in special cases. Here we propose an expanded coherence framework that enables contribution analysis in any multi-input system, regardless of input correlation. We bridged the gap by defining three new coherence measures: component, excluded, and isolated coherence. Component coherence is an intermediate measure that decomposes measured output power into components attributable to inputs directly vs …

Trustworthiness And Trust: Identifying Factors That Drive Successful Human-Ai Interaction In Nuclear Power Plant Applications, Yusuke Yamani, Austin Jackson, Casey Kovesdi, Jeffrey Joe, Jeremy Mohon

Psychology Faculty Publications

Emerging technologies such as artificial intelligence (AI) and machine learning are rapidly evolving and promising tools for efficient and continued safe operations of the U.S. nuclear power plants (NPPs). Emerging AI techniques like large language models (LLMs) are one such technology that may help personnel at existing NPPs perform work more efficiently. For example, operators may query the current operational status of a power plant via a chat interface, leveraging LLMs to access plant-related information in an interactive manner rather than manually collecting various sensor data for surveillance or work order tasks. This is a fundamental shift in the way …

Design, Fabrication, & Laboratory Testing Of A Strain Gage Instrumentation System For Marine Applications, Salem C. Homrighausen

UNF Graduate Theses and Dissertations

A strain gage-based instrumentation system was designed and fabricated to measure the moment present at the base of a mock, diesel-engine snorkel for a submerged vehicle designed to operate in the surf zone. Afterwards, a lab experiment was designed and executed to determine the accuracy of the instrument and a 2-dimensional, matrix-vector equation was formulated to relate pairs of voltages, Vx and Vy, to moments, Mx and My for the experiment. Three versions of this model were built. The first model was created using traditional statics equations governing strain, stress, moment, force. The second and third models were built directly …

Continuing Development Of An Unmanned Vehicle For Conducting Scientific And Engineering Operations In The Littoral Zone, Peter S. Bohn

UNF Graduate Theses and Dissertations

The beach and near shore are among the most economically and environmentally important regions on earth, yet they remain poorly understood due to the challenges of surveying the surf zone and obtaining other important data during high-energy events. Traditional methods such as wading surveys, small watercraft, and specialized vehicles like the coastal research amphibious buggy (CRAB) are limited by safety risks, high mobilization costs, and restricted operating windows. The work conducted in this effort addresses these limitations by continuing development of a remotely operated vehicle (ROV) intended to be operational in harsh surf conditions to collect high-resolution bathymetric and hydrodynamic …

Identification Of Fiducial Points In Seismocardiographic Cycles Using Manual And Automated Annotation Methods, Jasmine-Vy T. Truong

Honors Undergraduate Theses

There is currently a need for complementary methods for non-invasive cardiac monitoring. Seismocardiography (SCG), the measurement of cardiac-induced vibrations at the chest surface, has shown potential clinical utility. Improving the reliability of detecting fiducial points of electrocardiography (ECG) and SCG, which collectively capture the electro-mechanical cardiac activities, could expand ECG/SCG utility as a low-cost, accessible tool for clinical assessment. This study identifies commonly accepted criteria for fiducial point detection in SCG and ECG through an extensive literature review and signal processing techniques. The previous criteria were evaluated to identify their strengths and weaknesses. Based on the findings, an improved set …

Mill Power Consumption And Fuel Particle Size Distribution While Co-Milling Bituminous Coal With Steam-Exploded Woody Biomass In A Conventional Bowl Mill, Brian Schoof, Rajarshi Roy, Regan Kuttler, Parker Latour, Scott Montgomery, Jacob Tuttle, Gwendolyn Bennett Bennett, Brian D. Iverson, Andrew Fry

Faculty Publications

The mill behavior of a 312 Combustion Engineering Raymond Bowl Mill was studied with five blends of Utah bituminous coal and steam-exploded woody biomass, ranging from 100 % coal to 100 % biomass. Mill power consumption increased with biomass content, peaking at 187 % of the power required for 100 % coal before the mill faulted at 100 % biomass. After repositioning the rollers, power consumption for 100 % biomass decreased by 13 % compared to 100 % coal. SEM images revealed that milled biomass particles were non-spherical, indicating some fibrous structure remained post steam-explosion. The particle size distribution (PSD) …

Drop Dynamics During Condensation On Superhydrophobic Surfaces In Vapor Shear Flow, Shaur Humayun, R. Daniel Maynes, Julie Crockett, Brian D. Iverson

Faculty Publications

Accurate models for predicting drop dynamics, such as maximum drop departure sizes, are crucial for estimating heat transfer rates during condensation on superhydrophobic (SH) surfaces. Previous studies have focused on examining the heat transfer rates for SH surfaces under the influence of gravity or vapor flowing over the surface. This study investigates the impact of surface solid fraction and texture scale on drop mobility in a condensing environment with a humid air flow. Experiments recorded condensation with varying surface feature sizes from micro- to nano scale under different flow rates. Video analysis detected the drop-size distribution and maximum drop departure …

Digital Twins For Flexible Manufacturing, Drew Brandon Sander

Theses and Dissertations

With the establishment of Digital Twins as an enabling technology for Industry 4.0, it is time to transition from the previous foundations to works that implement and highlight the capabilities Digital Twins present. The Industry 4.0 paradigm has recentered the focus on customizability, leading to reemerging goals of flexibility within manufacturing. Empowered through new cyber-physical systems, new enabling technologies are driving the revolution. To identify how Digital Twins as an enabling technology contribute to flexibility within manufacturing, a comprehensive investigation is conducted along with a detailed case study. A systematic literature review is conducted to analyze quality Digital Twin implementations …

Novel Redox Oxygen Active Materials For Solid Oxide Cells And Thermochemical Hydrogen Production, Jiaxin Lu

Theses and Dissertations

This dissertation investigates novel materials designed to significantly enhance the performance and durability of oxygen electrodes for solid oxide cells and redox active materials for thermochemical hydrogen production. The first part of this work evaluates Ta-doped BaCoO₃₋δ (BCT) and its structural analog SrCoO₃₋δ (SCT), focusing on their catalytic performance in oxygen reduction and evolution reactions. Among BCT compositions (x = 0.1, 0.3, 0.5), the BCT10 (x = 0.1) composition exhibited the highest oxygen vacancy concentration, electronic conductivity, and lowest polarization resistance. However, SCT10 surpassed BCT10 in these critical performance parameters and also demonstrated greater stability over extended operational periods. Notably, …

Advances In Battery Modeling And Management Systems: A Comprehensive Review Of Techniques, Challenges, And Future Perspectives, Seyed Saeed Madani, Yasmin Shabeer, Ananthu Shibu Nair, Michael Fowler, Satyam Panchal, Carlos Ziebert, Hicham Chaoui, Shi Xue Dou, Khay See, Saad Mekhilef, Françios Allard

Electrical & Computer Engineering Faculty Publications

Energy storage systems (ESSs) and electric vehicle (EV) batteries depend on battery management systems (BMSs) for their longevity, safety, and effectiveness. Battery modeling is crucial to the operation of BMSs, as it enhances temperature control, fault detection, and state estimation, thereby maximizing efficiency and preventing malfunctions. This paper thoroughly examines the most recent advancements in battery and BMS modeling, including data-driven, thermal, and electrochemical methods. Advanced modeling approaches are explored, including physics-based models that incorporate mechanical stress and aging effects, as well as artificial intelligence (AI)-driven state estimation. New technologies that facilitate data-driven decision-making, real-time monitoring, and simplified systems include …

Safety And Sustainability In The Domestic Ferry Sector : A Pci Framework For Esg-Aligned Maritime Governance, Mirza Zeeshan Baig

World Maritime University Ph.D. Dissertations

The domestic ferry sector is a significant component of maritime transportation. It strengthens social ties, supports economic growth and connects communities. Despites its importance, this industry faces ongoing challenges. These include fragmented governance, operational adequacies, safety risks and environmental concerns. The study deals with these issues by combining a systems-based approach with governance and change management theories. It examines the interplay between human, technical and organizational aspects. The study integrates the rule-based and rights-based maritime governance along with the Lewin’s three stage change management model (Unfreeze, Change, and Refreeze).

At the core of the study is the development of a …

Advanced Air Preheater Sealing Systems For Enhanced Efficiency And Reliability In Thermal Power Plants, Pavan Kumar Ravulaparthy

Theses and Dissertations

Global electricity generation still relies heavily on thermal power plants, which consume vast amounts of fuel and emit significant amounts of carbon dioxide. A major but often overlooked source of inefficiency in these plants lies within the rotary regenerative air preheater (RAPH), a critical heat-exchange component where air leakage can exceed 20% in aging units. This leakage increases fuel consumption, parasitic fan power, and CO₂ emissions, while degrading boiler reliability.

This research introduces advanced adaptive sealing systems designed to mitigate these losses by dynamically compensating for rotor eccentricity, thermal distortion, and wear under harsh operating conditions. Brush seals, composed of …

Implementation Of Quantized Artificial Neural Networks With Spintronic Stochastic Computing, Saadi Sabyasachi Mr.

Theses and Dissertations

Artificial intelligence or machine learning is going through a rapid expansion. It also incurs significant costs for power and device footprints. Various approaches are being explored to design energy and hardware efficient machine learning models. Stochastic computing has been proposed for efficient machine learning implementation. It requires a source of random number generation which poses some practical challenges. So spintronic solutions such as magnetic tunnel junction has been used for random number generation. Again, spintronic random number generation to implement high precision circuit is prone to device-to-device variations. Hence we designed quantized artificial neural network with spintronic stochastic computing which …

Reverse Geometric Dispersion In The Beaufort Sea: Dissecting Sound Propagation At Long Ranges In Ducted Profiles, Jessica Desrochers

Open Access Dissertations

Acoustic propagation in the Arctic is evolving as surface temperatures increase and ice melts, resulting in a changing sound propagation environment. This study investigates the acoustic arrival structure in the Canada Basin and its connection to the underlying sound speed profiles. Two Seagliders were deployed in the summer of 2016 and 2017, diving in a sawtooth pattern collecting conductivity, temperature, and depth (CTD) data as part of the Canada Basin Acoustic Glider Experiment (CABAGE). These data are used to calculate sound speed profiles used to predict and understand acoustic arrival structures.

The warming of the Pacific Summer Water and surface …

Internally Stowed, Radially Deployed Radiator Panels For Passive Cubesat Thermal Control, Josh R. Cannon, Kyle N. Havey, Noah S. Housley, Rydge B. Mulford, Brian D. Iverson

Faculty Publications

CubeSats experience significant thermal loads due to solar irradiation and the dissipation from electrical components. The high heat dissipation per unit volume can lead to mission failure if not properly managed. Deployable radiators that are externally stowed and passively actuated in response to changes in CubeSat temperature have been explored as a viable solution. This work describes a radially deployed fin array that is stowed within the CubeSat body when the required heat dissipation is low and passively deploys when the required heat dissipation is high. Internal stowage improves thermal transport to the deployable fins and minimizes heat loss when …

Actuator Disk Model For Aeropropulsive Coupling Effects In Vortex Particle Method, Eduardo Alvarez, Vineet Ahuja, Vinod Lakshminarayan, Aaron Perry, Ryan Anderson, Andrew Ning

Faculty Publications

Blown lift and distributed electric propulsion aircraft pose strong aeropropulsive coupling effects that cannot be ignored during the early stages of design. In this study, we develop an advanced actuator disk model (ADM) for aeropropulsive coupling effects of ducted fans with the vortex particle method (VPM). The advanced ADM consists of (1) an actuator disk at the rotor plane, (2) a surface vortex sheet modeling the mixing and convection of blade tip vorticity along walls, and (3) a powered wake at the exhaust. With these three components, a propulsion jet with an arbitrary velocity profile is formed and interactions with …

Comparing The Sensitivity And Specificity Of Novel Motor Assessments For Traumatic Brain Injury, Paula K. Johnson, Ariana M. Hedges-Muncy, Erin D. Bigler, Lorie Richards, Steven Knight Charles

Faculty Publications

Background: Portable technology that records movements with high accuracy provides potential for sensitive clinical movement tests for individuals who experienced a traumatic brain injury (TBI). Objective: (1)To present impairments assessed using markerless motion capture (MMC) and (2) to compare the sensitivity and specificity of the MMCmediated tests to each other and to common clinical tests. Design: Screening study, using as criterion standard the ability to classify participant with TBI versus control participant. Setting: Research laboratory. Participants: The study included 30 individuals with TBI and 101 control participants. Entry criteria included most recent head injury < 5 years old, no history of movement issues prior to injury, no movement-affecting medications, and sufficient cognitive ability to follow instructions. Interventions: Not applicable. Main Outcome Measures: Performance on MMC-mediated tests and existing clinical analogs. MMC-mediated tests included finger oscillation, simple reaction time, and visually guided movement tasks. For comparison, participants also completed the following clinical tests: Halstead–Reitan finger tapping, simple reaction time test, and Beery Visuomotor Integration test. Impairments were identified as test scores of participants with TBI that fell outside of the 95% interval of control participants’ test scores. Random forest analysis was used to calculate the sensitivity and specificity of MMC and clinical tests according to their ability to correctly classify participants with TBI and control participants. Results: MMC-mediated tests revealed impairments in more participants with TBI than clinical tests in all three TBI groups (mild, repeated, and moderate to severe). Similarly, MMC-mediated tests revealed a higher percentage of scores as impairments than clinical tests in all three groups with TBI. Furthermore, MMC-mediated tests proved more sensitive and more specific than clinical tests (70% versus 50% and 98% versus 93%, respectively). Conclusion: MMC-mediated tests are sensitive and specific (compared to traditional clinical tests) and have potential to fill a gap in clinical care of TBI.

Process To Design And Analyze Dynamic Environment Test Fixtures (Pdadye), Cora J. Taylor

Dissertations, Master's Theses and Master's Reports

Vibration qualification testing is an important requirement in many industries. In-lab testing is intended to evaluate a component’s life expectancy by exposing it to a dynamic environment similar to what it may experience in its field condition. To successfully perform these tests, it is imperative that the field boundary conditions (BCs) of the component of interest are replicated as closely as possible in the lab. One approach to achieving accurate dynamic environment testing is to design a fixture that sufficiently represents the impedance of the next-structure (field structure). The process to design and analyze dynamic environment test fixtures (PDADyE) is …

Measuring Occupant Controlled Ventilation And Cooking Frequency To Aid In Modeling Energy Performance Of Northern Michigan Homes, Jacob J. Chizek

Dissertations, Master's Theses and Master's Reports

This research investigates the real-world interplay between energy efficiency and indoor air quality. We explore how home ventilation strategies, heating systems, and weatherization levels in rural homes interact. As part of a larger study on air quality, 17 homes participated in the study. Specifically, this research shows the results and methods for monitoring cooking frequency, kitchen range hood use, and bathroom fan use over two, month-long study periods to build accurate energy and contaminant transport models of homes that were studied. Energy audits to document home characteristics were conducted, including blower door testing and detailed qualitative data regarding the homes’ …

Intelligent Systems For Synergistic Optimization Of Vehicle Dynamics And Energy Consumption In Connected And Automated Vehicles, Aman Poovalappil

Dissertations, Master's Theses and Master's Reports

This dissertation focuses on the development and validation of on-board, real-time estimation algorithms and the investigation of energy-saving strategies for modern light-duty vehicles, including connected and automated vehicles (CAVs). The accurate estimation of key vehicle parameters is critical for enhancing energy efficiency, enabling advanced driver-assistance systems (ADAS), and optimizing vehicle performance and energy efficiency. First, this research introduces a novel real-time algorithm to dynamically learn vehicle mass using readily available sensor data. Based on longitudinal vehicle dynamics, a sensitivity analysis was conducted to identify the conditions under which mass estimation is most robust. The algorithm was extensively validated through on-road …

Holistic Energy Efficiency Analysis Of Electrified Off-Highway Material Handler: From Drive Cycle Characterization To Powertrain, Hydraulic, And Thermal System Performance, Alexander Czarnecki

Dissertations, Master's Theses and Master's Reports

Three complexities surrounding the operation and testing of hybrid electric, heavy-duty nonroad machines have been addressed experimentally and using 1D simulation. Their resolutions have been intertwined with the development of a prototype machine that was proven to reduce fuel consumption in excess of 20%. A real-world drive cycle that leveraged hydraulic cylinder position was developed and utilized to ensure accurate reproduction of hydraulic work between the baseline and hybrid machines, while simultaneously maintaining less than 5% RMS error in position for main load handling functions. The newly developed, machine-specific drive cycle also contributed towards making equivalent comparisons in energy consumption …

Investigation Of Acoustic Attenuation Methods As A Noise Control Device In Hydraulics, Sophia R. Bollin

Dissertations, Master's Theses and Master's Reports

This research covers a variety of hydraulic configurations to characterize wave propagation and transmission loss. This is mathematically calculated via a transfer matrix that separates the acoustic pressure waves into upstream and downstream. Although there is a solid mathematical basis (ASTM E2611) for these calculations, a range of tests were performed to compare the accuracy of these calculations to real-time data. The main set of tests were performed on a two-part impedance tube setup with a sample section in the center. A total of 13 dynamic pressure transducers (DPT’s) are placed along the bench to record the pressure throughout testing. …

Stepper Motor Load Estimation Using A Neural Network, Soham S. Kulkarni

Dissertations, Master's Theses and Master's Reports

Bipolar stepper motors are common in scenarios that require low-cost precision including 3d printers. The ability to estimate stepper motor load provides an opportunity for health monitoring. For example, excessive load estimates may indicate a future problem in the driven system such as bearing wear. Stepper motor drivers often have built-in stall detection strategies that exploit the driver's precise knowledge of the high-frequency voltage pulses being sent to the motor. The goal of this work was to develop a retrofit approach to stepper motor load estimation using externally measured voltage, current, and speed. A stepper motor dynamometer was created to …

Study Of Two-Phase Void Fraction In A Rectangular Channel Using Capacitance Sensor, Peter Ngoc Nguyen

Dissertations, Master's Theses and Master's Reports

Two-phase liquid-gas flow has many applications in the nuclear industry, including active heat exchangers, reactor core designs, secondary steam generators, and two-phase flow loop balance of the plant. The void fraction is a crucial parameter to determine the pressure drop, flow regimes and liquid levels inside the nuclear reactor core. For the past forty years, void fraction has been studied by many researchers by different measurement techniques. Each method has positive and negative attributes. In this study, after extensive literature reviews, the author has chosen a capacitance type void fraction sensor over other void fraction measuring techniques. The principal concept …