Engineering Commons^™

Measurement Of Groundwater And Contaminant Fluxes In Fractures Using A Combined System Of Passive Flux Meter And Multiport Sampler, Qasim Raza Khan

Dissertations

Groundwater and contaminant movement in fractured rock aquifers is highly variable. Its dependence on fracture apertures and orientation as well as fracture network interconnectivity is not well understood. This poses a challenge to the measurement of groundwater and contaminant fluxes, especially when using open-hole techniques, which significantly alter natural flow conditions by connecting different fractures along an open borehole or a well. Hence, downhole techniques to directly measure groundwater fluxes and map fractures' locations, orientations, and apertures are considered valuable tools. In this work, the use of Fractured Rock Passive Flux Meter (FRPFM) with invisible tracer and visible dye component …

Techniques For Enabling Advanced Adas Features: Operation In Inclement Weather And Use Of Infrastructure Information, Parth Kadav

Dissertations

Modern vehicles have undergone a transformation with the widespread integration of Advanced Driver Assistance Systems (ADAS) technology becoming the new standard and are set to be mandated by the by the National Highway Traffic Safety Administration (NHTSA) for all passenger vehicles and light trucks. ADAS features have proven to prevent or mitigate crashes by either alerting or assisting the driver. ADAS typically utilizes a forward-facing camera, which comes standard in modern vehicles to provide limited automation features such as Lane Keeping Assist (LKA), and Lane Centering Assist (LCA) to improve driver safety. These systems rely on the assumption that vehicle …

Emission Behavior At The Single Emitter Scale From A Porous Media Ionic Liquid Ion Source, Thomas Victor Kerber

Dissertations

Ionic liquid ion sources (ILIS) are being developed as one solution to fill a technology gap in low power, high efficiency, high specific impulse space propulsion systems. With a sufficiently intense electric field applied between an emitter electrode and an extractor electrode, charged particles are extracted from the fluid surface and accelerated out of the thruster. In this work, three experimental campaigns examine emission behavior of a single emitter ILIS made of porous material that allows passive propellant feed via capillary action of the ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate (EMI-BF₄).

Repeated measurements of the emitter and extractor current as …

Data-Driven Decision Making For Quality Control In Foundry Applications, Ronit Shetty

Dissertations

In the transformative landscape of Industry 4.0, advanced quality control in manufacturing demands innovative methods for processing and analyzing datasets. This dissertation presents a comprehensive study on leveraging high volume data and machine learning to enhance decision making in the foundry industry. The research explores three crucial challenges in the foundry industry: predicting surface roughness, monitoring refractory coating thicknesses, and comparing feature extraction techniques for surface quality classification. The findings underscore the transformative potential of integrating advanced feature engineering techniques and machine learning into manufacturing quality control.

The first of the three challenges introduces a framework that integrates digital images …

Turbulence And Energetic Ion Production In The Partially Magnetized Hollow Cathode Plume, Margaret Mary Mooney

Dissertations

Hall effect thrusters (HETs) are the most widely used electric propulsion (EP) device for in-space satellite propulsion. EP devices provide high efficiencies for extended mission lifetimes and low thrust for precision maneuvers. The hollow cathode is a critical HET component and undergoes extensive lifetime testing in addition to the lifetime testing of the full HET. Significant density gradients, non-Maxwellian electron behavior, and magnetic fields sufficiently strong enough to magnetize electrons in hollow cathode plumes create favorable conditions for the formation of plasma instabilities, which have an impact on cathode lifetime. Cathode qualification testing is typically conducted independently and includes a …

Navigating Big Data In Cyber Archaeology: An Updated Four-Field Approach Applied To San Miceli, Jared Wilson

Dissertations

Problem

This dissertation examines the evolving role of digital technologies in archaeological research, focusing on the management and interpretation of extensive digital datasets generated by modern excavations. Drawing on six years of comprehensive fieldwork at San Miceli, Sicily, this study critically evaluates and updates the established four-field methodology proposed by Levy et al. (2012), encompassing acquisition, analysis, dissemination, and curation. While traditional archaeological documentation methods rely heavily on analog techniques, these approaches increasingly fall short due to the rapid expansion and complexity of digital data.

Method

To address this gap, the dissertation refines and expands the current methodological framework by …

First-Principles Study Of Ferroelectric Properties And Co2 Reduction Reaction Capabilities In Two-Dimensional Monolayers And Heterostructures, Mo Li

Dissertations

Two-dimensional (2D) materials hold significant potential for CO₂ reduction reactions (CO₂RR) due to their high surface-to-volume ratio. However, achieving high selectivity for desired products and overcoming limitations posed by scaling relationships remain challenging. Recent studies suggest that ferroelectric (FE) materials with switchable out-of-plane polarization (OOP) can effectively tune the adsorption behavior, thermodynamics, and kinetics of CO₂RR, offering promising solutions to these challenges. Using density functional theory (DFT) and the Berry phase approach, this work expands the family of 2D ferroelectrics by theoretically identifying Y₂CO₂, Y₂CS₂, and Sc …

Determination Of Electrochemical Parameters For Predicting Reaction Mechanism And Algorithmic Approaches To Pain Assessment, Huize Xue

Dissertations

This dissertation introduces novel advancements in electrochemical kinetics and pain assessment, structured into two main parts. The first part focuses on the comprehensive analysis of the kinetic and mechanistic aspects of electrochemical reactions, utilizing a combination of experimental techniques and simulation methods. A new software tool, Envismetrics, was developed using Python to facilitate the analysis of complex electrochemical data, including cyclic voltammetry (CV), chronoamperometry (CA), and hydrodynamic voltammetry (HDV). The software was rigorously tested and validated with well-characterized redox systems such as the ferricyanide/ferrocyanide couple, dimethylamine borane (DMAB), and Per- and Polyfluoroalkyl Substances (PFAS). It was successfully used to determine …

Gas-Generating Reactive Materials: Design, Evaluation And Effect Of Morphology On Their Ignition And Combustion, Purvam Mehulkumar Gandhi

Dissertations

This work investigates optimizing gas-generating reactive materials, focusing on particle morphology's effect on ignition and combustion behavior. Metal-based gas-generating energetic materials (EMs) are promising alternatives to replace traditional CHNO compounds. Design of advanced metal-based EMs requires consistent ways of evaluating how their characteristics affect their ignition and combustion. Many relevant evaluation approaches exist; however, the results may be difficult to compare directly across different studies. Commonly, experimentalists ignite metal-based EMs in enclosed chambers and report pressures, P. However, direct comparison of these pressures is hindered by variations in the chamber volume, V, and the EM mass, m. To standardize the …

Decomposition Of Diisopropyl Methylphosphonate (Dimp) Exposed To Elevated Temperatures And Combustion Products Of Reactive Materials, Elif Irem Senyurt

Dissertations

The safe and efficient destruction of chemical weapon agents (CWAs) stockpiles remains a critical global challenge. Understanding the thermophysical properties, decomposition mechanisms, and interactions of CWAs with their environment is crucial for developing effective strategies to mitigate their threats. Diisopropyl methylphosphonate (DIMP) and Dimethyl methylphosphonate are commonly used nerve agent surrogates. This dissertation focuses on DIMP and DMMP, investigates their properties and behavior under conditions relevant to prompt defeat scenarios.

The thermophysical properties of DIMP and DMMP were experimentally characterized, including vapor-liquid surface tension (3-60 °C) and viscosities of neat and aqueous solutions. Results revealed significant non-ideal behavior in aqueous …

Faulty Perception Correction Of Autonomous Vehicles In Real-Life Driving Scenarios, Mark Omwansa

Dissertations

Driving is one of the most popular modes of transportation in the world. The United States Department of Transportation’s (USDOT) Federal Highway Administration (FHWA) reported 2.8 trillion vehicle-miles traveled (VMT) in 2020, and the National Highway Traffic Association (NHTSA) recorded 3.2 trillion VMT in 2019. Also recorded in the NHTSA report were 39,096 fatalities and 2.7 million injuries due to traffic accidents, costing the economy an estimated $242 billion. Most of these recorded accidents can be attributed to human error or misjudgment. It is for this reason that governments and the automotive industry are looking at autonomous vehicle (AV) technologies …

Influence Of Glycopolymer Structure On Amphiphilic, Hybrid, Linear Branched Block Copolymer Properties For Use In Biomedical Applications, Kevin Green

Dissertations

The focus of this dissertation is evaluating and adding fundamental knowledge regarding the structure-property relations of glycopolymers used in the design of hybrid block copolymers (HBC) that are cable of self-assembling into delivery vehicles for biomedical applications. A shift to the utilization of natural materials in the design and fabrication of drug-delivery vehicles has garnered significant attention. Understanding the effects of linear glycopolymers content and composition on the resulting HBCs properties can provide valuable insight into how these materials may be tailored for use in targeted biological applications.

The first chapter introduces current literature on the need for improvement in …

Synthesis, Characterization And Testing Of Graphene-Based Materials For Proton-Exchange Membrane Fuel Cell Catalysts, Hassan Shirzadi Jahromi

Dissertations

The requirement for low cost and efficient catalysts for fuel cells motivated the proposed research on Nitrogen-doped reduced graphene oxide (N-rGO) integrated with transition metal zeolitic imidazolate frameworks (ZIFs). Synthesis, characterization and performance evaluation of the newly synthesized nitrogen-doped graphene oxide-based catalysts for Proton Exchange Membrane Fuel Cells (PEMFCs) constitutes the main objective of this thesis.

The synthesis of N-rGO combined with cobalt, nickel, or iron ZIFs was carried out using wet chemical methods followed by one step pyrolysis at 900°C, resulting in catalysts with highly porous structures and uniform metal nanoparticle distribution. These were characterized for structure, microstructure, composition …

Structural Behavior Of Corroded Reinforced Concrete Beam Elements Repaired With Fabric-Reinforced Matrix Composites, Youssef Ibrahim Elmezayen

Dissertations

Advanced methods for rehabilitation of reinforced concrete (RC) beams with corroded reinforcement were designed and implemented in this research. The nonlinear flexural and shear behaviors of RC beams with corroded reinforcement repaired with fabric-reinforced matrix (FRM) composites were investigated. Numerical simulation models were developed to predict the flexural response of flexure-deficient continuous RC beams before and after repair with FRM composites. A novel sustainable repair solution that involves the use of cement-free geopolymeric matrix reinforced with nonmetallic fabrics was also introduced for rehabilitation of shear-critical RC beams with corroded stirrups. Simplified and easy-to-use analytical approaches were adopted to estimate the …

Performance Of Pervious Geopolymer Concrete Made With Locally Available Recycled Concrete Aggregates In An Arid Environment, Faizu Habibu Anwar

Dissertations

This dissertation aims to develop sustainable pavement materials to address environmental challenges in arid environments, specifically in the United Arab Emirates (UAE). These challenges include the depletion of natural resources, excessive cement production, industrial waste accumulation, and stormwater runoff flooding. Cement-free pervious concrete made with geopolymer and recycled concrete aggregates (RCA) are presented as sustainable solutions to these issues. The porous nature of pervious concrete reduces stormwater runoff while using RCA and geopolymer reduces dependence on limited natural resources and mitigates the environmental impact of cement production by incorporating industrial waste materials. In this thesis, the use of pervious geopolymer …

Use Of Cement-Free Geopolymer Composites In Different Construction Applications, Joud Mohamad Hewalla

Dissertations

The demand for sustainable and eco-friendly construction materials has driven significant interest in the development of cement-free Geopolymer (GP) composites. A comprehensive scientometric analysis was conducted, highlighting a steady increase in research on geopolymer materials since 2013, with fire resistance, corrosion protection, and repair being the most studied applications. However, gaps remain in areas like 3D printing, heavy metals absorption, rehabilitation and repair, screed flooring, and shotcrete. The review emphasized the need for further investigation into lifecycle assessments and the potential use of diverse alumina- and silica-rich binders to enhance the environmental and mechanical properties of geopolymers. Accordingly, this thesis …

Investigating The Neurovascular Correlates Of Cognitive Function In Individuals With Spinal Cord Injury Using Functional Near-Infrared Spectroscopy, Donna Yali Chen

Dissertations

Individuals with spinal cord injury (SCI) have a 13 times greater risk of cognitive impairment than able-bodied individuals and commonly report symptoms of depression and anxiety. The reports of cognitive impairment in individuals with SCI are independent of concomitant brain injury. Although the direct cause of cognitive impairment in individuals with SCI is unknown, key contributors may include comorbid depression, chronic pain, anxiety, fatigue, brain injury, or cardiovascular dysfunction. Previous studies have focused on SCI at the level of the spinal cord but have under-investigated the supraspinal levels. Due to the lack of neuroimaging studies on SCI rehabilitation, it is …

A Micromagnetic Study Of Skyrmions In Thin-Film Multilayered Ferromagnetic Materials, Nicholas J. Dubicki

Dissertations

Magnetic skyrmions are topologically protected, localized, nanoscale spin textures in non-centrosymmetric thin ferromagnetic materials and heterostructures. At present they are of great interest to physicists for potential applications in information technology due to their particle-like properties and stability. In a system of multiple thin ferromagnetic layers, the stray field interaction was typically treated with various simplifications and approximations. It is shown that extensive analysis of the micromagnetic equations leads to an exact representation of the stray field interaction energy in the form of layer interaction kernels, a so-called 'finite thickness' representation. This formulation reveals the competition between perpendicular magnetic anisotropy …

Federated Learning Systems For Mobile Sensing Data, Xiaopeng Jiang

Dissertations

Federated Learning (FL) has emerged as a new distributed Deep Learning (DL) paradigm that enables privacy-aware training and inference on mobile devices with help from the cloud. This dissertation presents a comprehensive exploration of FL with mobile sensing data, covering systems, applications, and optimizations.

First, a mobile-cloud FL system, FLSys, is designed to balance model performance with resource consumption, tolerate communication failures, and achieve scalability. In FLSys, different DL models with different FL aggregation methods can be trained and accessed concurrently by different apps. In addition, FLSys provides advanced privacy-preserving mechanisms and a common API for third-party app developers to …

Data Driven Decision Making For Sustainable Planning And Operations Of Large Scale Networks, Bahareh Kargar

Dissertations

This dissertation explores data-driven decision-making networks, focusing on sustainable planning and operations for large-scale systems such as healthcare supply chains and power systems. One significant application in healthcare is the optimization of vaccine supply chains. An agent-based simulation-optimization modeling framework is developed to enhance the efficiency and sustainability of vaccine distribution. First, an agent-based epidemiological model of COVID-19 is extended to capture disease transmission dynamics and forecast the number of susceptible individuals and infections. Then, a sustainable vaccine supply chain considering the impacts of greenhouse gases is developed and integrated with the simulation model to minimize total costs and environmental …

Electrified Membrane For Water Treatment And Resource Recovery: Advancing Multiscale Strategies In Gas-Involving Reactions, Jianan Gao

Dissertations

Multifunctional, modular, and scalable water treatment technologies that operate without chemical additives are crucial for addressing global water pollution challenges. While traditional membrane-based separation processes are crucial for ensuring clean water supplies, they primarily focus on pollutant removal rather than on the upcycling of pollutants into valuable resources. Electrified membrane filtration presents a robust alternative, utilizing minimal or no chemical additives and harnessing electrical power to directly reduce contaminants or produce reactive oxidants or reductants on-site.

This dissertation is dedicated to the development of innovative electrochemically reactive membranes designed to address three major challenges: (1) the engineering of electrocatalysts with …

Microwave Catalysis-Enabled Membrane Processes For Microbial Inactivation, Fangzhou Liu

Dissertations

The COVID-19 pandemic has highlighted the urgent need for advanced technologies to combat virus transmission. Traditional membrane filtration technologies primarily serve as physical barriers, capturing pollutants but failing to inactivate microbial agents such as bacteria and viruses. These membranes typically target larger particles but are ineffective against sub-micrometer viral particles. Thus, there's a critical demand for membrane filtration processes that combine robust filtration with antifouling and reaction -enabled functions for efficient pathogen disinfection. This research explores a novel microwave-assisted membrane filtration process incorporating catalytic reactions to enhance microbial disinfection and prevent membrane fouling, offering a groundbreaking solution to global challenges …

Estimation Of Spo2 Levels And Heart Rate From Ppg Signals In The Presence Of Motion Artifacts, Chizhong Wang

Dissertations

In the rapidly advancing world of health technology, wearable devices are at the forefront, fundamentally changing how individuals monitor their health. The key to this transformation is photoplethysmography (PPG), a non-invasive optical method that measures blood flow variations through the skin by detecting changes in light absorption with each heartbeat. This capability makes PPG essential for monitoring vital signs such as heart rate and blood oxygen saturation(SpO₂). Furthermore, the utility of PPG signals has been extended beyond traditional health metrics to include human activity classification, offering a holistic perspective on an individual's physical health and activity levels, in …

Order-Picking Strategies And Efficiency Models For The Fulfillment Of Multi-Line E-Commerce Grocery Orders, Zijia Wang

Dissertations

The fulfillment process for Buy Online Pickup from Store grocery orders (BOPS-Grocery) is particularly challenging, given the large item count per order and the low-profit margins. This research investigates the BOPS-Grocery model and pursues the following objectives: (i) Defining and specifying the BOPS-Grocery fulfillment process. Differentiating the process from classical warehouse order picking., identifying performance objectives, and characterizing design options and facility layout. (ii) Modelling and developing order picking algorithms specific to the straight aisle section. Formulated as an order hatching problem with picker movement minimization. No order splitting, and (iii) modeling and developing order picking algorithms specific to the …

Collision Dynamics Of Compound Droplets In Microchannels: A Combined Numerical And Data-Driven Study, S M Abdullah Al Mamun

Dissertations

Understanding and predicting the hydrodynamic interactions of micron-scale droplets is crucial in a wide range of industrial and real-life applications, including microfluidics, pharmaceutics, drug delivery, food science, and enhanced oil recovery. These multi-phase and multi-scale phenomena are further complicated by the presence of core droplets of an immiscible fluid within shell droplets, known as compound droplets. The collisions and interactions of droplets in emulsions are influenced by various physical and geometric parameters, leading to distinct rheological and dynamic responses. This research employs numerical methods for a systematic parametric study of both simple and compound droplet pair collisions under confined shear …

Development And Structural Origin Of Stretchable Semiconducting Polymers And Composites, Yunfei Wang

Dissertations

Stretchable semiconductors are pivotal in advancing wearable and implantable electronics, with those boasting both high stretchability and self-healing capabilities being especially significant for a myriad of wearable applications. In this dissertation, we developed an extremely soft, highly stretchable, and self-healing elastomer based on H-bonding crosslinked amide-functionalized polyisobutylene (PIB-amide). When blended with a high-performance conjugated diketopyrrolopyrrole (DPP-T) polymer, the composite exhibits unprecedented stretchability, exceptionally low elastic modulus, and an innate ability to self-heal at room temperature.

The morphology of conjugated polymer/elastomer semiconducting composites have significant impacts on electrical and mechanical properties Further investigations focused on manipulating the phase separation size in …

Localized Hermite Method Of Approximate Particular Solutions, Kwesi Acheampong

Dissertations

A localized Hermite method of approximate particular solutions (LHMAPS) is presented in this dissertation. This method is designed to improve the accuracy of the localized method of approximate particular solutions (LMAPS) for solving partial differential equations. LMAPS is a strong-form method that defines local radial basis function approximations to the solution values at a group of collocation points before applying the differential operator to this approximation function. Based on the LMAPS's local scheme, LHMAPS seeks Hermite-type local approximations based on both function values and derivatives. Numerical experiments validate the superior accuracy of the proposed method to the LMAPS by solving …

Medical Imaging Dataset Management Leveraging Deep Learning Frameworks In Breast Cancer Screening, Inchan Hwang

Dissertations

In the domain of Computer-Aided Diagnosis (CADx) for breast cancer diagnosis through mammography, prevailing models have traditionally been trained and validated using old film-based mammography. However, contemporary U.S. hospital practices involve the utilization of Full Field Digital Mammography (FFDM), offering more detailed images captured at various angles than old film-scanned mammography. Despite this shift, the existing body of research predominantly focuses on old-film based datasets, the implications of FFDM for CADx systems have not been understood. This dissertation addresses the issues emerged from FFDM such as data augmentation between old film-based set and new FFDM whether they are more effective …

Poly(Thioether) Thermosets With Gated Photodegradation, Surabhi Jha

Dissertations

Photodegradable polymer networks are attractive due to the precise spatiotemporal control and large-area applicability of light. Chemical linkages that enable these polymer networks to be photo-responsive, also hinder their applicability in ambient light. Photostable and photodegradable networks have recently been reported to overcome this challenge by combining other stimuli with light for degradation. We report the design of a network that responds to a simultaneous, dual stimulus for photodegradation. We design poly(thioether acetal) networks with benzylidene acetal moieties that are known to undergo β-scission in the presence of free thiols. By blocking these free thiols with a thermally labile protecting …

Remote Vibration Based Monitoring Of Bridge Scour, Alan Kazemian

Dissertations

The gradual erosion of the sediment around a bridge foundation is called Scour. This erosion is caused by water flow and increases during times of high-water flow such as flooding. The scour leaves the bridges structurally unsound over time and jeopardizes the safety of the structure. Approximately 60 percent of bridge failures in the United States are caused by scour. A variety of types of devices have been used to detect scour. Most of these devices only observe the scour and not the structural integrity of the bridge. The typical approach has relied on visual inspections of the bridges after …