Engineering Commons^™

Laser-Based Wideband Guided Ultrasonic Wave Inspection Of Isotropic And Anisotropic Materials, Andrew Philip Campbell

Theses and Dissertations

Non-destructive evaluation (NDE) and structural health monitoring (SHM) have experienced significant growth in both capability and utility as material evaluation and damage detection methods for structural components throughout various industries over the past two decades. Evaluating a structure throughout its life cycle or on demand as needed can identify critical weaknesses that impact safe operation and may prevent failures. Various NDE/SHM methods have been shown to be effective; among them, guided ultrasonic waves (GUW), particularly Lamb wave-based methods, have been intensively studied due to their capability to interrogate internal defects and their relatively larger coverage. With the advancements in new …

Graphene Synthesis: A Reactor-Oriented Review Of Conventional And Emerging Production Methods, Paul C. Ani, Zeyad Zeitoun, Hasan J. Al-Abedi, Joseph D. Smith

Chemical and Biochemical Engineering Faculty Research & Creative Works

Graphene's unparalleled electrical, mechanical, and thermal properties have positioned it as a transformative material across diverse sectors, including electronics, energy storage, biomedicine, and environmental remediation. However, scalable, cost-effective, and high-quality production remains a critical challenge. This review presents a comprehensive, reactor-oriented analysis of both conventional and emerging graphene synthesis methods, categorized into top-down and bottom-up approaches. Special emphasis is placed on the role of reactor configurations in determining product quality, layer control, scalability, and economic viability. Key synthesis techniques explored include chemical vapor deposition (CVD), epitaxial growth, electrochemical exfoliation, ultrasonic-assisted methods, microwave reactors, combustion synthesis, and plasma-enhanced processes. By evaluating …

Analysis Of Live Load Distribution Factors In Prestressed Concrete Girder-Bridges With Asymmetric Losses In Prestressing Strands, Mohamed T. Elshazli, Mohamed Elgawady, Ahmed Ibrahim

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Asymmetric loss of prestressing strands in concrete bridge girders presents a critical yet underrecognized threat to structural integrity, particularly in exterior girders subjected to impact or localized deterioration. This form of localized and unbalanced damage leads to eccentric reductions in prestressing force, rotation of the principal axis, and diminished flexural capacity, effects not explicitly addressed in current design standards such as the AASHTO LRFD Bridge Design Specifications. This study presents a comprehensive numerical investigation into the structural implications of such asymmetric damage, focusing on its effect on live load distribution factors (LLDFs) across prestressed girder bridges. A parametric study of …

Behavioral-Centric Team Evaluation Via Consistent Rewards, Clement Kudakwashe Nyanhongo

Dartmouth College Ph.D Dissertations

Across human domains ranging from sports to business and organizational settings, complex tasks are often solved by teams rather than individuals, leveraging benefits such as interaction, mutual support, complementary skills, cohesion, and task allocation. Evaluating team effectiveness, however, is inherently challenging due to the subjectivity of many existing techniques and the limitations of outcome-driven metrics that primarily focus on performance scores while overlooking the team processes that generated the scores. To address these challenges, this dissertation proposes a behavioral-centric, end-to-end framework for team evaluation grounded in reward functions that model sequential team behavior. Reward functions offer compact and interpretable representations …

Advancement And Characterization Of Next-Generation Solid-State Photon-Counting Image Sensors For Astrophysics Applications, Nicholas R. Shade

Dartmouth College Ph.D Dissertations

Astronomers’ pursuit of detecting light from increasingly faint and distant objects in the expanse of space necessitates continuous improvement in signal-to-noise ratio of camera technology. Recent advancements in solid-state detector technologies have enabled the determination of photon-number, including single photon events, enabling observations at the fundamental limits of physics. These developments are instrumental not only for standard two-dimensional imaging but also for advanced spectroscopy, which increasingly drives future astrophysical applications. This thesis presents an evaluation of three next-generation silicon-based detectors capable of photon-counting with deep-sub-electron input-referred read noise: the electron-multiplying charge-coupled device (EMCCD), the single-photon avalanche diode (SPAD), and the …

Electromyography, Prosthetic Properties, And Running Biomechanics In Recreationally Active Persons With Lower Extremity Amputation, Paige M. Agnew

Rehabilitation Sciences Theses & Dissertations

Lower extremity loss affects nearly 150,000 individuals in the United States yearly yielding extreme health care costs annually. Typically, prosthetic devices are prescribed for 5-8 years despite known changes to an individual’s gait as time progresses. Patients can expect to undergo approximately 8-12 weeks of gait retraining to improve their comfort and efficiency. Biomechanical changes occur when running with a specific running prosthetic including considerable biomechanical and neuromuscular interlimb asymmetries and alterations in loading patterns. The purpose of this dissertation was to investigate the biomechanical demands for lower extremity prosthesis users during running. The first study synthesized peer reviewed evidence …

Microstructural And Thermal Studies Of Niobium On Copper Fabricated By Sputtering And Multicharged Ion Deposition, Md Obidul Islam

Electrical & Computer Engineering Theses & Dissertations

Niobium-coated copper (Nb/Cu) superconducting radiofrequency (SRF) cavities are a promising alternative to bulk niobium cavities for next-generation particle accelerators due to their reduced material cost and superior thermal conductivity of the copper substrate. However, cavity performance is fundamentally limited by the microstructural quality of sputtered Nb films and thermal transport across the Nb/Cu interface. Reduced thermal diffusivity in thin films and high interfacial thermal resistance contribute to localized heating and performance degradation under high RF fields. This dissertation addresses these challenges through a combined experimental and methodological investigation of thermal transport in Nb thin films, focusing on interface engineering using …

A Theoretical Framework For Recursion In Complex System Governance, Gilbert Goddin

Engineering Management & Systems Engineering Theses & Dissertations

The purpose of this research was to construct an original theoretical framework for understanding recursion in Complex System Governance (CSG), grounded in the propositions and axioms of systems theory and management cybernetics. This framework addresses a research gap for cybernetic recursion relating to the governance of complex systems. Leveraging the CSG framework (Keating & Katina, 2019; Keating, 2022), holonic principles (Koestler, 1970; Mella, 2009), management cybernetics (Beer, 1979; Beer, 1984; Beer, 1995), and metacybernetics (Yolles, 2021; Yolles & Fink, 2015c; Yolles & Frieden, 2021), recursion is theorized as a governable capability, whereby metasystemic governance anticipates emerging complexity and purposefully regulates …

Fabrication Of Flexible Laser-Induced Graphene-Based Non-Enzymatic Glucose Sensor For Diabetes Management, Reagan Aviha

Electrical & Computer Engineering Theses & Dissertations

This research focuses on developing a flexible non-enzymatic glucose sensor to address the issues of cost, stability, and limited sensitivity associated with enzymatic glucose sensors. Regular monitoring of glucose levels is required to manage the global health challenge of diabetes. The sensor is built on a cost-effective, durable, flexible, conductive, and high-surface-area substrate acting as a scaffold for modification with easily tunable and electroactive species to enhance glucose detection. The electroactive materials used are zinc oxide (ZnO), palladium (Pd) and platinum (Pt). Laser-induced graphene (LIG) is created by laser engraving. ZnO, Pd and Pt are electrochemically deposited and optimized based …

Optimizing Auv Perception For Competitive Underwater Robotics: Analyzing Performance And Simplicity Of Machine Vision Hardware, Joseph King

Honors Theses

Underwater robotics is a growing field with many practical applications, such as pipeline and offshore structure monitoring, deep sea mining, mine reconnaissance/removal, and marine environmental monitoring. USM’s Robotics Club will participate in the international RoboSub competition, where student-led teams build autonomous underwater vehicles (AUVs) that perform a variety of tasks within a pool requiring camera-based object detection. This project analyzes affordable hardware and software options for providing machine vision to USM’s future RoboSub AUV. The performance of an ESP32-CAM microcontroller, Raspberry Pi 5, and Jetson Orin Nano single-board computers running FOMO and YOLO object detection models was compared. These models …

Efficient Energy Management In Networked Microgrids Using Multi-Agent Deep Reinforcement Learning In The Presence Of Uncertainties, Ayodele Benjamin Chukwuyem

Dissertations

Microgrid technology is essential in facilitating the transition to smart energy grids in developed countries and mitigating energy poverty in developing countries, particularly in areas where grid extensions are not feasible. Recently, the concept of networked microgrids (NMGs) has garnered tremendous attention due to the plausibility of interactions among interconnected microgrids leading to power networks that are more resilient, reliable, and stable. However, because each microgrid has diverse distributed generation resources (renewables and controllable generators) and each microgrid operator (MO) has different objectives, coordinated energy management is required to satisfy local and system-wide goals under conditions with significant uncertainty. Existing …

A Low-Noise And High-Gain Integrated Photoplethysmography Sensor For Continuous Vital Signs Monitoring, Neethu Mohan

Dissertations

Photoplethysmography (PPG) sensing is an important technology used for measuring health parameters like, heart rate, respiratory rate, blood oxygen saturation, and blood pressure (BP). The PPG sensing is used for individuals who have to periodically monitor their health due to chronic health conditions. The basic requirements of a wearable PPG sensor include non-invasiveness, prolonged battery life, and being userfriendly. These type of sensors have great demand in the healthcare applications and there is a significant rise in the demand of these sensors. The basic objective of these PPG sensors is to make the continuous vital health monitoring easier without the …

A Comparative Study On Performance Of Iot-Driven Ml-Enabled Forecasting Models For Efficient Air Quality Monitoring, Bara Ksiksi

Theses

Air pollution is one of the most critical environmental challenges affecting public health globally, responsible for approximately 4.2 million premature deaths annually according to the World Health Organisation. This thesis presents a comparative study of IoT-driven machine learning forecasting models for air quality monitoring in Abu Dhabi, UAE, introducing a zonal approach combined with satellite-based spatial validation. The primary objective is to evaluate forecasting performance across three distinct activity zones using ground station data from the Environment Agency Abu Dhabi (EAD), and to incorporate a spatial validation component using satellite imagery to assess the consistency of ground-based predictions at a …

Traditional And Machine-Learning Equalization Techniques For Bandwidth-Limited Short-Reach Optical Communication Channels, Abdullah Khawatmi

Theses

This thesis investigates equalization techniques for bandwidth-limited short-reach optical communication systems, with a focus on Visible Light Communication (VLC) and Step-Index Plastic Optical Fiber (SI-POF) links. Commercial light-emitting diodes and photodiode receivers impose severe bandwidth constraints, inter-symbol interference, and noise sensitivity, which fundamentally limit achievable data rates. The work addresses these impairments through systematic evaluation of traditional digital signal processing–based equalizers and modern machine-learning-based post-equalization methods. The primary aim of this thesis is to enhance the achievable data rate and reliability of commercial short-reach optical links while maintaining practical computational complexity. Specifically, the objectives are to (i) design and experimentally …

Modeling And Autonomous Control Systems For A Delivery Drone Application, Dana Helal Alnuaimi

Theses

This thesis focuses on the development of a multi-drone navigation and control system, aiming to enhance payload capacities beyond the limits of single-drone systems. By integrating multiple drones to work collaboratively as a unit, this study addresses the challenges associated with lifting and transporting heavier payloads.

The primary objective is to design and evaluate a multi-drone system capable of working in tandem to transport larger payloads efficiently. The research aims to develop robust control algorithms, supported by system identification for dynamic modeling, and navigation strategies to enable effective coordination between drones.

The study employs a combination of simulation and real-world …

Analysis Of A Coaxial Transmission Line Filled With An Orthorhombic Dielectric-Magnetic Medium, Fathima Manikunnath Abdul Akbar

Theses

Coaxial transmission lines are fundamental means for Transverse Electromagnetic (TEM) wave propagation in RF, microwave and high-speed electronic systems. The study of transmission lines is often familiar when they are filled with isotropic materials; however modern engineered direction dependent materials reshape field distributions. In this thesis, we consider a coaxial transmission line of an inner radius and outer radius b filled with an orthorhombic dielectric-magnetic material, which is described by two anisotropy parameters αx and αy. The potential and field distributions are studied in relation to the ratio b/a as well as the anisotropy parameters αx and αy. Due to …

Efficient Fpga Implementation Of A 1 Million-Point Fft, Jwaher Abdulqader Al Tamimi

Theses

The one-million-point Fast Fourier Transform is implemented using a radix-2 single-path delay feedback pipeline architecture. To minimize the computational overhead, twiddle factors were pre-computed and stored in memory. The design uses a fixed-point representation with two integer bits and seven fractional bits, achieving a measured signal-to-noise ratio of 37.98. Given the substantial memory requirements, a memory partitioning approach was used. It mapped the delay buffers in each stage lookup table memory, block random-access memory, or ultra random-access memory, based on word width and memory depth.

The implementation operates successfully at 100 megahertz on a mid-scale field-programmable gate array. Post-implementation reported …

Breath-Based Detection Of Liver Cancer Biomarkers Using An Swcnt-Fet Nano-Biosensor: Quantumatk, Mohamed Mohieb Rashdan

Theses

Early detection of liver cancer remains limited by the slow pace and invasiveness of current testing methods. This study proposes a single-walled carbon nanotube field-effect transistor (SWCNT-FET) designed to detect hexanal—a volatile organic compound (VOC) elevated in liver cancer—directly from exhaled breath. The device is modeled in QuantumATK using a semi-empirical Extended Hückel Hamiltonian within the non-equilibrium Green's function (NEGF) framework, emphasizing realistic contact physics by employing metallic SWCNT electrodes instead of conventional metal films. Zigzag channels with (11,0) and (12,0) chiralities are examined to analyze how geometry and contact matching influence charge transport. Simulations include current–voltage (I–V) characteristics and …

Development Of A Novel Cfd Approach For Predicting Multiphase Flow Enhanced By Machine Learning, Abdulrahman Elazazi Salem

Theses

Accurate estimation of interface orientation is crucial for ensuring both the accuracy and robustness of Volume of Fluid (VOF) schemes in multiphase flow simulations, especially when using non-uniform Cartesian meshes. Conventional gradient reconstruction approaches, such as least-squares (LSQ) methods, often suffer from significant errors and strong oscillations on highly stretched grids. This work proposes a grid-transferable, learning-based methodology that predicts interface unit normal vectors directly from the local volume-fraction field on nonuniform structured Cartesian grids using a feedforward neural network. The methodology extends earlier work originally developed for uniform grids, which is first reproduced to assess how performance deteriorates in …

Study Of The Effect Of Biodiesel Derived From Jojoba Oil With Alcohols Blends On Diesel Engine Performance, Exhaust Emissions, Vibration, And Noise, Yassir Abdelrahman Elbashier

Theses

This study presents a mutual investigation on the properties of the fuels and the performance of an engine using biofuels from mixtures of jojoba oil biodiesel with alcohols. The work consists of mainly two phases, examining the properties of the jojoba biodiesel-alcohols mixtures and the performance and emission behavior in a single piston diesel engine. A base mixture of 50% jojoba biodiesel and 50% diesel produced, and this was fractionally mixed with 5, 10, and 20% methanol and with 5, 10, and 20% diethyl ether (DEE). The rheological properties namely viscosity and shear stresses of all biodiesel blend mixtures were …

A Dataset Of Precipitate-Containing Multi-Principal Element Alloys, Anshu Raj, Xin Wang, Matthew Luebbe, Haiming Wen, Kun Lu, Shuozhi Xu

Materials Science and Engineering Faculty Research & Creative Works

We report a curated dataset that brings together composition, processing conditions, microstructural details, and mechanical properties for 396 combinations of alloy composition and processing condition drawn from 100 peer-reviewed research articles on precipitate-containing multi-principal element alloys (MPEAs). The dataset was created by first utilizing a generative large language model for information extraction, followed by expert review to ensure accurate recovery of materials data. Compositional information was taken directly from tables and text, while processing routes — including homogenization, rolling, recrystallization, and aging — were converted into uniform temperature and time metrics. Microstructural descriptors, including precipitate phases and sizes, were consolidated …

Development Of A Benchmark Building Condition Index Utilizing Discrete Facility Subsets For Use In Risk Prioritization Analysis, Christopher A. May

Engineering Management & Systems Engineering Theses & Dissertations

Within the healthcare facilities management arena, key performance-based condition indices such as a calculated Building Condition Index (BCI) are currently utilized as a governing indicator of facility health and performance. However, BCI alone does not adequately support enterprise-level risk prioritization and fails to provide a validated facility-to-facility risk prioritization model. Assets within the same enterprise receiving similar sustainment funding experience different rates of degradation depending on asset type and construction age thus impairing the BCI rating scale. Statistical analysis of facility metrics indicates a strong correlation between facility degradation drivers and prediction of a subset-based benchmark BCI. The research validates …

Exploring Hemodynamic Signatures Using Event Camera, Zaid Ahmed

McKelvey School of Engineering Graduate Student Theses & Dissertations

This thesis investigates event-based sensing for hemodynamic measurements in transmission mode through the human finger. Conventional frame-based imagers are limited by exposure time, frame rate, and motion blur, which reduce sensitivity to fast optical transients. To address these bottlenecks, this thesis introduces a novel transmission-mode sensing framework using a Prophesee EVK4 HD neuromorphic sensor. By capturing asynchronous ON/OFF events generated by local intensity changes, this work presents a new approach to three tasks: intra-finger pulse transit time (PTT) and pulse wave velocity (PWV) estimation, event-based transmission mode laser speckle contrast imaging (LSCI), and Flicker Spike Arrival Time (FSAT) Delay Mapping, …

Examining Self-Efficacy And Gender In Rural Secondary Engineering Education, Laine Schrewe, Tiffany Karalis Noel

The Rural Educator

Addressing the gender gap in engineering necessitates a thorough understanding of self-efficacy, and this study specifically focused on engineering self-efficacy of adolescent girls in secondary school. It identifies patterns linking rural students’ engineering self-efficacy to other areas of their lives to unearth trends for students with high engineering self-efficacy that could be used to help overcome this gender gap. The study used a mixed-methods instrumental case study approach and clarified the relationships between high engineering self-efficacy and various aspects of life for rural students, such as academic performance, extracurricular activities, and implicit gender beliefs, thus offering critical insights for educational …

An Integrated Bayesian Network-Based Zero Trust Model To Quantify Cyber Risk In Small-Medium Businesses, Ahmed Abdelmagid

Engineering Management & Systems Engineering Theses & Dissertations

Small-medium businesses (SMBs) play a pivotal role in the worldwide economy as they constitute the most considerable portion of businesses in developed countries like the UK and the US. As such, SMBs are likely targets of cybercrimes by malicious agents because of their vulnerable IT systems. The digital infrastructure of SMBs is more likely to be hit by cyberattacks than large businesses due to many factors that facilitate hackers’ missions. These factors include a limited financial budget devoted to cybersecurity, a lack of knowledge, an underrating of how dangerous cyber threats are, and a shortage of IT expertise. The enormous …

Workforce Resilience In Public Transportation Agencies, Kristal D. Metro

Civil Engineering ETDs

A strong, resilient public workforce is necessary to keep the United States’ infrastructure system running smoothly. Across the public sector, hiring is lagging behind increasing retirement rates, leaving public agencies facing the loss of institutional knowledge at unprecedented levels. Combined with above-average retirement rates, low unemployment rates, and below-average salaries, workforce shortages are expected to become critical, putting the resilience of the public transportation workforce, and by extension, the United States public infrastructure and services at risk. The purpose of this research is to determine the best practices for recruiting and retaining employees at public transportation agencies, thereby positively influencing …

Life Cycle Costing Of Modular Timber Residential Construction, Logan Micah Hammel

Construction Management

This study examines the economic feasibility of modular residential construction using life-cycle costing (LCC) and life-cycle assessment (LCA) approaches to assess the sustainability and maintenance costs of modular construction. Using the structures and documents from the Gateway Decathlon project as the subject, we applied LCC formulas and programs to assess their economic performance. These calculations were conducted manually in Excel and modeled using the OpenLCA platform to compare traditional and software-based approaches. The study aims to identify cost drivers across building scopes, such as building materials and electrical and mechanical systems, and to evaluate how modular construction performs over its …

Sustainability In Concrete: Decision-Makers, Dismissal Points, And A Framework For Implementation, Max Dennison

Construction Management

Concrete is essential to modern infrastructure, but is also one of the largest sources of embodied carbon, with cement production alone responsible for a significant share of global CO₂ emissions. Although low-carbon and otherwise “sustainable” concrete technologies are growing, their use in everyday projects remains limited. This research investigates why sustainable concrete options are most often dismissed during the project lifecycle, who drives these decisions, and what conditions are needed to enable broader adoption. Using a combination of literature review and semi-structured interviews with professionals in contracting, life-cycle assessment, sustainability consulting, and materials production, the study maps decision points from …

An Ultrafine-Resolution Numerical Investigation Of The Influence Of Terrain On Tornado Behavior, Jiamin Dang, Jana Houser, Leigh Orf, Peng Yue, Guirong Yan

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This study investigates the effects of idealized and realistic terrain on tornado characteristics and behavior. It uses a novel simulation approach, nesting a high-fidelity, ultrafine-resolution, tornado-scale, engineering large-eddy simulation (LES) within a Cloud Model 1 (CM1) simulation of a tornadic supercell. We analyze the effects of terrain on the tornado's central pressure, horizontal and vertical velocities, vortex shape, and path. Seven idealized terrain configurations are used including 1) a control run with flat ground, 2) and 3) an idealized hill with steep and gradual slopes having the height of 25.4 m, 4) and 5) an idealized escarpment with steep and …

Instrumentation And Control Of A Novel Device To Simulate A Hypersonic Environment, Andrew Marcello

Doctoral Dissertations and Master's Theses

The hypersonic flow regime poses several challenges regarding the design of hypersonic vehicles. Among them is the massive energy and economic expense associated with ground- testing evaluation of material responses within this extreme environment. In order to provide a low-cost, rapid option for preliminary material analysis within hypersonic applications, a novel device is under production to replicate this environment on the surface of these materials. This device has been designed to work in conjunction with Argonne National Laboratory (ANL) Advanced Photo Source (APS) synchrotron, to allow for in-situ characterization of ablation and oxidation on the sample surface.

To achieve this, …