Engineering Commons^™

Bayesian Alloy Design With Additive Synthesis, Michael R. Sulwer

Dissertations, Master's Theses and Master's Reports

To reduce carbon emissions and increase power out, steam powerplants need to increase the operating temperatures and pressures of steam turbines to improve efficiency. This necessitates the development of high temperature alloys with superior strength and stability. This research aims to design a class of solid solution High Entropy Alloys (HEAs) to exceed the high temperature performance of commercial alloys like Haynes 230 while maintaining comparable costs for Advanced Ultra Supercritical (A-USC) steam cycles. This project integrates Bayesian optimization and Calculation of Phase Diagrams (CALPHAD) within an Integrated Computational Materials Engineering (ICME) framework to predict and optimize key material properties: …

Leveraging Product And Process Characteristics Across The Concrete Pavement Life Cycle To Integrate Global Warming Potential Into Project Procurement Processes, Michelle Annette Cooper

Dissertations, Master's Theses and Master's Reports

The objective of this research is to support sustainable procurement of concrete pavements by linking materials-level global warming potential (GWP) to the project-level. Infrastructure owners require reliable environmental product declarations (EPDs) and methodologies for integrating GWP into the procurement process to ensure equitable decision-making. This work provides insights into current EPD reliability by assessing the sensitivity of concrete GWP to materials-level contributors to recommend a level of supply chain specificity needed to effectively communicate GWP. A benchmarking methodology was developed and implemented to establish reference values for procuring sustainable products. Having provided evidence towards EPD reliability, this work presents a …

Biomedical Applications Of Reactive Oxygen Species From Catechol Oxidation, Zhongtian Zhang

Dissertations, Master's Theses and Master's Reports

Catechol, a key functional moiety found in mussel adhesive proteins, undergoes oxidation to generate reactive oxygen species (ROS), which can be leveraged for biomedical and environmental applications. By modifying catechol-based polymers, ROS generation can be controlled and applied toward organic compound degradation, antimicrobial treatments, and polymer crosslinking. This dissertation focuses on the design and application of catechol-based materials that leverage ROS generation for biomedical and environmental applications.

Ansi Z97 Impact Testing Of Thin Glass, Justin P. Anthony

Dissertations, Master's Theses and Master's Reports

To determine whether thin glass constructions can pass Z97 impact test to qualify as safety glass an extensive protocol was performed. Constructions including monolithic, chemically strengthened, filmed, laminated, and triple pane insulated glass units comprised of thin glass ranging in thickness between 0.50 mm and 1.6mm were evaluated. Test results indicate annealed specimens, and laminated specimens performed similar to constructions with 3 mm and 6 mm glass. Specimens with 0.2 mm film consistently performed as safety glass for thicknesses between 0.7 mm and 1.6 mm and similar performance for specimens with 0.1 mm film with thickness of 1.1 mm and …

Life Cycle Assessment And Techno-Economic Analysis Of Mine Tailings As A Sustainable Raw Material For Mineral Carbonation And Recovery Of Critical Minerals, Vida Amankwaa

Dissertations, Master's Theses and Master's Reports

This study assesses the feasibility of using mine tailings for mineral carbonation and nickel recovery through a comprehensive Life Cycle Assessment (LCA) and Techno-Economic Analysis (TEA). The LCA quantifies greenhouse gas emissions, energy use, and resource consumption, while the TEA evaluates capital investment, operational costs, and process efficiency. The conventional beneficiation process at Eagle Mine serves as a baseline, highlighting its environmental footprint and operational costs. Results indicate that tailings reprocessing incurs higher costs ($34.76 per tonne of tailings processed) compared to conventional ore processing ($25.90 per tonne) due to increased energy consumption and material handling requirements. Additionally, several mineral …

Life Cycle Assessment Of Renewable Hydrocarbon Fuels Produced By The New Cool Gas To Liquid (Cool Gtl) Process, Elochukwu Okoye

Dissertations, Master's Theses and Master's Reports

The Cool Gas-to-Liquid (Cool GTL) process converts biogas and captured CO₂ into renewable hydrocarbon fuels, contributing to GHG emissions reduction in transportation. This report explains a Life Cycle Assessment (LCA) study that was completed to evaluate the environmental impact of different feedstocks, hydrogen sources, and electricity inputs. The analysis considers biogas from food waste, manure, and landfill sources, as well as biogenic, fossil, and direct air capture (DAC) CO₂ feedstocks. Results show that biogas pathways provide the greatest GHG reductions, with the best case (food and manure biogas + solar hydrogen + solar electricity) achieving a net-negative GWP …

Life Cycle Assessment And Life Cycle Cost Assessment Of A Floating Treatment Wetland In A Wastewater Lagoon Located In Copper Harbor, Michigan, Erin Browne

Dissertations, Master's Theses and Master's Reports

A full-scale floating treatment wetland was implemented in a wastewater treatment lagoon in Copper Harbor, Michigan. Copper Harbor is a small, rural community located in a cold climate. Many studies have focused on the performance of floating treatment wetlands in mesocosm studies in warmer climates, but there is not a lot of research conducted on the feasibility and performance of full-scale floating treatment wetlands in wastewater lagoons, specifically in cold climates. The 2024 treatment season was the first season with the floating treatment wetland implemented in the wastewater lagoon. A preliminary assessment of the cost and environmental impacts of a …

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 …

Microbial Inactivation And Spray Drying For The Recovery Of Single-Cell Protein From Chemically Deconstructed Polyethylene Terephthalate, Reeba Elizabeth Reji

Dissertations, Master's Theses and Master's Reports

Polyethylene terephthalate (PET) is one of the most widely used polymers in plastics packaging. However, the increasing demand for PET has created challenges in waste disposal. Previous research has shown that PET can be deconstructed using ammonium hydroxide (CDPET). Microorganisms capable of utilizing the product as a sole carbon source can be converted to single-cell protein (SCP). A custom microbial inactivation unit was developed to ensure the safety and stability of generated SCP. Our study evaluated the effect of exposure time (45–60 minutes) at 140 °C with the goal of maximizing microbial inactivation. Our findings suggest that microbial inactivation can …

Developing Inexpensive Sensors That Can Detect Roof Collapse From Snow Loads, Edward Sandy

Dissertations, Master's Theses and Master's Reports

In cold regions in the United States, residential timber structures are susceptible to roof collapses due to heavy snow accumulation. The recent updates in ASCE 7-22 have introduced reliability-targeted ground snow loads, leading to significant increases in design snow loads for certain areas. Despite this development, existing buildings in these regions designed under historical code requirements may be under-designed for snow load. This fact provides motivation to owners of these structures to pursue effective monitoring and mitigation strategies to prevent structural failures. This research focuses on the development of an early warning system utilizing cost-effective slope monitoring sensors to estimate …

Development And Validation Of Novel Force Reconstruction Algorithm For Traction Force Microscopy, Samuel E. Haarman

Dissertations, Master's Theses and Master's Reports

Traction Force Microscopy (TFM) is a powerful technique for quantifying cellular traction forces, yet its accuracy is dependent on the force reconstruction algorithm used to recover traction forces from the input substrate deformations. As such, the use cases of TFM are dependent on the types of reconstruction algorithms available. To expand the usability of TFM onto micropatterned substrates, we introduce gFEM, a novel force reconstruction method that incorporates the specific grooved topography of the user’s experimental substrate into the solution process. Unlike other traditionally used models, which assume a flat and continuous substrate, gFEM aims to improve the fidelity of …

Community Diversity And Makeup Affect The Capacity For Bioconversion Of Chemically Deconstructed Pet Plastic Waste Into Biomass, Hunter Stoddard

Dissertations, Master's Theses and Master's Reports

Plastic waste management is an issue worldwide, particularly for locations with challenging logistics, such as remote locations, those impacted by natural disasters, and regions with armed conflict. These locations also struggle with food logistics and malnutrition. It is possible to tackle both issues by combining chemical deconstruction to depolymerize plastic waste with microbial conversion of the liquid product into biomass that can be used as an edible protein powder. The focus of this work is on the bioconversion of products from the chemical deconstruction of polyethylene terephthalate (PET) using ammonium hydroxide. Microbial communities have previously been shown to utilize the …

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 …

Direct Methane Capture Via Aerobic Methanotrophs, Waaseyaaban Landgren

Dissertations, Master's Theses and Master's Reports

Methane, a greenhouse gas with global warming potential 80 times greater than carbon dioxide, heavily contributes to global warming. Removing 1 Gt of atmospheric methane by 2050 would limit global temperature increase from reaching 1.5°C. Currently, biotrickling filter systems for removing atmospheric methane via methanotrophs exist, but not for very low methane concentrations (< 1 v%). Current research work at the University of Washington isolated and engineered a microbe strain which thrives at 500 ppmv methane, solving one obstacle in making this technology feasible. In this thesis, techno-economic analysis and environmental life cycle assessment conducted on this process have assessed its economic feasibility, greenhouse gas reduction potential, and possible areas of improvement. Study results show that at 500 ppmv methane, this process could remove atmospheric methane at a cost of $3,992-5,224 per tCH₄. The ideal case also produces annual net reduction in warming potential by 276-311 tCO₂e per process unit deployed.

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. …

Generalizing Medical Image Segmentation Task With Efficient Deep Learning Models, Abel A. Reyes-Angulo

Dissertations, Master's Theses and Master's Reports

Medical Image Segmentation is a critical task in the field of medical imaging, playing a crucial role in diagnostics, treatment planning, and disease monitoring. The emergence of Deep Learning (DL) has ushered in a new era in Artificial Intelligence (AI), propelling remarkable advancements in key domains like language translation, object recognition, and recommendation systems. This evolution has been accompanied by continuous enhancements in computational efficiency and improvements in predictive accuracy. The introduction of sophisticated algorithms, such as convolutional neural networks (CNNs) and transformers, exemplifies these advancements. DL algorithms have demonstrated exceptional efficacy in medical image segmentation tasks, showcasing the potential …

Estimating Unconfined Compressive Strength (Ucs) Of Rocks From Measurement While Drilling (Mwd) Data, Can Erdem

Dissertations, Master's Theses and Master's Reports

Measurement-while-drilling (MWD) technology enables the real-time monitoring of drilling parameters during the drilling process. MWD data can provide valuable insight into the mechanical behavior of intact rocks and rock masses, which is essential for geotechnical applications such as foundation design and underground construction. The aim of this study is to correlate real-time drilling parameters, recorded using a laboratory-developed MWD system, with the unconfined compressive strength (UCS) of rocks. A custom laboratory MWD system was designed to simultaneously record four key drilling parameters: thrust (axial force, crowd), torque, penetration rate, and rotational speed. The custom-built MWD system was used to continuously …

Design And Control Of Reversible Adhesion: Switchable Adhesive Molecules And Electrochemical Approaches, Kan Wang

Dissertations, Master's Theses and Master's Reports

Smart adhesives are materials that can reversibly gain or lose adhesion in response to external stimuli such as temperature, pH, electric fields, or light. Their switchable and temporary adhesion makes them highly promising for applications in wound healing, manufacturing, and robotic locomotion. Among them, catechol-based polymers have been widely studied for pH- and electro-responsive adhesion, due to their reversible non-covalent crosslinking. However, their performance is limited by irreversible covalent crosslinking reactions and the need for conductive surfaces in electrochemical systems. While boronic acid has been used to protect catechol, its reversibility remains limited. Therefore, new adhesive molecules and system designs …

Performance And Environmental Impact Of Waste Glass Asphalt In Cold Regions, Kai Xin

Dissertations, Master's Theses and Master's Reports

The reuse of waste glass in asphalt mixtures has significant potential in sustainable pavement engineering, yet its performance under cold, freeze–thaw conditions remain underexplored. This dissertation presents a first-of-its-kind comprehensive evaluation of glass asphalt for cold regions, simultaneously assessing its low-temperature cracking resistance, moisture susceptibility, field performance, and life-cycle environmental impacts. A series of laboratory tests were performed on asphalt mixtures incorporating various proportions of crushed waste glass aggregate, including Disk-Shaped Compact Tension (DCT) and Indirect Tensile (IDT) tests for low-temperature fracture resistance, and Tensile Strength Ratio (TSR) and Hamburg Wheel Tracking (HWTT) tests for moisture damage and rutting susceptibility. …

Triboelectrostatic Separation Of Lunar Regolith, Hannah Peterson

Dissertations, Master's Theses and Master's Reports

Lunar regolith as a source of raw materials for a long-term human presence on the moon would need to be separated into single mineral fractions. To do this, triboelectric properties can be utilized to separate minerals without needing to add a working fluid, such as air and water, or expensive, consumable chemicals. A lightweight machine can be created to do this, one that also requires minimal electricity. A series of three prototypes for this machine were created and tested to determine if this concept would work, and what properties the machine would need. A mixture of magnetite and silica were …

Dam It All: A Multi-Scalar Investigation Into The Ecological Role And Function Of Beaver Dams, Kenneth Larsen

Dissertations, Master's Theses and Master's Reports

The central theme of this dissertation is ecological scaling, which examines how small, localized features, such as beaver ponds, contribute to large-scale watershed processes and how different modeling approaches at various scales reveal distinct insights. Through a combination of probabilistic modeling and high-resolution empirical research, this work demonstrates that small ponded systems, particularly those created by beavers (Castor canadensis), serve as critical biogeochemical control points, whose contributions to sediment and nutrient dynamics have been historically underestimated.

In Chapter 1, I contextualize this research within the broader fields of freshwater ecology, watershed modeling, and ecological restoration. I introduce the …

Ultrasound Shear Wave Elastography: Development Of Tissue Models And Investigation Of Shear Wave Variability, Emily J. Miller

Dissertations, Master's Theses and Master's Reports

Ultrasound shear wave elastography (USWE) is an evolving and promising clinical tool for noninvasively measuring in vivo soft tissue biomechanical properties. Assumptions incorporated into the clinical workflow and technical limitations have created gaps between theoretical and clinically derived solutions. The heterogeneity of the fibrotic liver tissue, composition of the background, such as the presence of fatty liver tissue, and the preferred local orientation of the scarred fibrotic liver tissues embedded into the liver parenchyma, may contribute to the uncertainty in USWE measurements. This study aims to systematically investigate four cofounding factors (i.e., size, volume fraction, orientation of the fibrotic inclusions, …

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 …

Linking Molecular Structure Evolution To Mechanical Degradation During Environmental Aging In Conventional And Recyclable Epoxy Systems, Ben T. Jewell

Dissertations, Master's Theses and Master's Reports

The long-term performance of polymeric materials in extreme environments is governed by complex chemical and physical aging processes that alter their molecular structure and mechanical integrity. Conventional thermoset epoxies, while widely used in structural applications, are particularly susceptible to oxidative degradation at elevated temperatures, leading to embrittlement and loss of structural integrity. In the first part of this work, diffusion-limited oxidation (DLO) in a bulk structural epoxy was systematically investigated to establish the link between heterogeneous microstructural evolution and macroscopic mechanical degradation. High-temperature oxidation experiments were conducted in a controlled environmental chamber, and the resulting chemical, thermal, and mechanical changes …

Iron Ore Tailings Reprocessing By Electrostatic Separation Plus Two Stages Froth Flotation, Vincent Bailey Arohunmolase

Dissertations, Master's Theses and Master's Reports

The reprocessing of tailings is crucial for recovering valuable iron and reducing the environmental impact associated with tailings disposal. This study investigates the practicality of reprocessing tailings to enhance iron oxide content, combining electrostatic separation with a two-stage froth flotation process using oleic acid (direct flotation) and amine (reverse flotation). The primary goal is to efficiently recover valuable iron from tailings, thereby reducing waste and promoting sustainable resource utilization. The process aims to upgrade the iron oxide content to around 93-99% Fe₂O₃, making the recovered material suitable for the production of direct-reduced iron.

Electrostatic separation was …

Degradation Of Polymers And Polymer Composites In Extreme Environments, Ben T. Jewell

Dissertations, Master's Theses and Master's Reports

Polymeric materials are widely used in engineering applications due to their high strength-to-weight ratio, easy manufacturability, and cost-effectiveness. When incorporated into composites, they provide further performance enhancements, enabling use in demanding structural applications. However, long-term exposure to harsh environments including elevated temperatures, UV radiation, harsh chemicals, and radiation, can drive degradation processes that alter the material’s network structure, and in turn, degrade its mechanical performance. Exposure to thermo-oxidative conditions is one of the most common environments driving polymer degradation, leading to chain scission and crosslinking events, with the resulting oxidative products causing discoloration, reduced ductility, and changes in glass transition …

Optical Methods For Time-Resolved Dosimetry And Oximetry Of Ultra-High Dose Rate Radiation Therapy, Megan A. Clark

Dartmouth College Ph.D Dissertations

Radiotherapy (RT) is a cornerstone method used to treat over 50% of the 2 million new cancer diagnoses each year in the United States. The success of RT directly relies on an optimal balance between maximizing the dose to the tumor while minimizing dose to surrounding normal tissues. Achieving this balance is often challenging due to underlying radiation transport and the presence of anatomical constraints that limit the beam delivery geometry. In turn, minimizing healthy tissue toxicity prevents use of a more aggressive tumor killing approach, and even in curative cases may decrease the patient’s quality of life due to …

Old, Flat, And Slow: Interior Greenland Snow And Ice Dynamics Revealed With Gnss, Derek James Pickell

Dartmouth College Ph.D Dissertations

The interior dry snow zone region of the Greenland Ice Sheet can no longer be confidently considered a reliably melt-free region, yet our ability to investigate and quantify the dynamic nature of this landscape is hindered by its remoteness. To overcome this challenge, this work describes a novel, low-cost, low-power GNSS (positioning) instrument that enables simultaneous measurements of (1) ice accumulation/ablation changes and (2) 3D ice flow. Deployed in a dense array, these GNSS instruments achieve similar performance to scientific-grade, commercial options (cm- to mm- precision), yet operate at < 60% of the power and < 34% of the hardware cost. Over a three year campaign, we analyze spatial and temporal patterns of accumulation in this region, using a technique called GNSS interferometric reflectometry (GNSS-IR). Observations with this technique show low bias and high precision relative to a validation study (-2.1 ± 2.9 cm), while we also demonstrate for the first time how GNSS-IR can reveal cm- to m- scale surface roughness, a critical yet often neglected measurement due to longstanding observational challenges. Patterns of accumulation show a spatial dependence linked to surface slope (~+0.7 mm w.e. km^-1 westward away from the divide) while surface roughness has a temporal dependence likely driven by wintertime high winds. Next, we combine GNSS-IR surface heights with the geodetic position time series of the antenna to derive surface elevation changes, which are compared to coincident ICESat-2 laser altimetry elevations. Observations of the surface show a millimeter-level relative bias and cm-level precision (-0.9 ± 3.8 cm) compared with the satellite altimeter, demonstrating for the first time that this technique is a viable ground-truthing method, while ICESat-2 performance has continued to exceed mission performance requirements. Finally, we examine station positioning through time to show a sensitivity to dynamic ice thinning and firn densification, two parameters than cannot be finely observed with space-based methods in this region. Together, these results provide the first ground‑based, high‑resolution picture of interior ice‑sheet change—capturing accumulation, roughness, surface elevation, and strain in one unified dataset. Our approach dramatically lowers logistical barriers, opening the interior of Greenland (and other remote regions) to sustained, quantitative monitoring at unprecedented spatiotemporal resolution.