Engineering Commons^™

Flex-Fuel Mixing-Controlled Combustion Enabled By Prechamber Ignition (Pc-Mcc), Jared J. Zeman

Dissertations (1934 -)

There is an imminent need to displace fossil diesel fuel with cleaner burning, domestically produced, renewable fuels for use in heavy-duty engines. Bioethanol is a prime candidate as it widely adopted in the U.S. as a gasoline additive ranging in volume percentage from 10% (E10) up to 85% (E85). Direct substitution of market available ethanol-gasoline blends for diesel fuel is not plausible as the stark reactivity differences would not constitute the same ignition quality nor achieve auto-ignition at all. This work focuses on the development of prechamber enabled mixing-controlled combustion (PC-MCC) as an advanced ignition strategy to facilitate reliable ignition …

A Sysml V2 Implementation Of A Traceability And Verification Metamodel For “-Ilities”, Pacifique Munezero

Engineering Management & Systems Engineering Theses & Dissertations

Multidisciplinary knowledge and exchange of information are two of the most important aspects of complex system design within the Model-Based Systems Engineering (MBSE) domain. The next generation of systems modeling language, SysML v2, is being developed to improve the precision, expressiveness, interoperability, consistency, integration of the language concepts relative to SysML v1, and the implementation and maturation of MBSE approaches. This research focuses on using SysML v2 to model structured notations for -ilities, referred to as non-functional requirements (NFRs), to address how they can be treated with the same rigor as functional requirements and mapped directly and explicitly from the …

A Theoretical Framework For Examination Of Context In Complex System Governance, Meggan M. Schoenberg

Engineering Management & Systems Engineering Theses & Dissertations

“A complex system’s identity and viability are directly related and affected by its context. It is important to identify, monitor, and manage (or mitigate risk) system contextual elements” (Keating C. B. et al., 2022, p. 209). Despite this importance, there is very limited research and literature on complex systems context. This research seeks to expand our understanding of complex system context and improve our ability to govern complex technology development programs effectively. The ability to analyze complex systems and their problems is necessary for this improvement.

A “clear understanding of the specific complex system context is fundamental to the process …

Development Of Highly Sensitive & Selective Sensor, Megha Shinde

Biomedical Engineering Theses & Dissertations

This work presents the development of innovative electrochemical sensors for selective and sensitive dopamine (DA) detection using flexible laser-induced graphene (LIG) electrodes modified with advanced nanocomposites. An LIG electrode synthesized from pyralux film was functionalized with Nb₄C₃Tx MXene and silver nanoparticles (AgNPs), significantly enhancing its electrochemical performance. The modified electrode exhibited a peak anodic current increase from 150 μA to 330.4 μA and demonstrated a wide linear detection range (100 nM to 10 μM) with a low detection limit of 1 nM and high sensitivity (160.96 μA/nM cm ^-2). It also displayed excellent selectivity against …

Identifying Contributing Factors Of Black American Females’ Long-Term Persistence In Stem Education: A Qualitative Phenomenological Study, Chandra T. Oaks-Garcia

STEMPS Theses & Dissertations

The purpose of this study was to gain insights into contributing factors that have shaped the experiences of eight Black American females who pursued STEM education as they persisted from the secondary education setting to their collegiate setting in a STEM major. This qualitative phenomenological study collected data through in-depth semi-structured interviews with Black American female juniors and seniors studying at four different four-year institutions, all pursuing degrees in STEM-related fields. Demographic surveys and memo writing were incorporated to enhance the data analysis. To explore the lived experiences of Black American females in STEM education and identify factors that contributed …

Development Of Laser-Induced Graphene-Based Bioanode Incorporating Thylakoid For Harvesting Energy, Amit Sarode

Biomedical Engineering Theses & Dissertations

Thylakoid-Based Biofuel Cells (TBFCs) present significant potential as renewable power sources; however, their development is impeded by challenges including delicate thylakoid membranes, limited electron transport efficiency, stability and dependence on expensive mediators. This study aimed to address these challenges by fabricating a novel photo-driven bioanode through the integration of Laser-Induced Graphene (LIG), Nb₄C₃T_x MXene, and thylakoid membranes. The fabrication process involved laser engraving to generate porous LIG electrodes, followed by MXene drop casting and thylakoid immobilization to enhance electrochemical performance and surface area. Morphological characterization supported that MXene incorporation increased active sites and surface roughness, …

Development Of Flexible Lactate-Specific Molecularly Imprinted Polymers Based On Laser-Induced Graphene Electrochemical Biosensors For Disease Diagnosis, Christopher Animashaun

Biomedical Engineering Theses & Dissertations

Lactate is a critical biomarker linked to conditions such as sepsis, ischemia, cancer, and heart failure. Current lactate detection methods remain invasive, costly, and unsuitable for real-time, continuous monitoring. This study presents the development of a flexible, non-enzymatic electrochemical biosensor based on laser-induced graphene (LIG) electrodes modified with gold nanoparticles (AuNPs) and molecularly imprinted polymers (MIPs) for highly selective and sensitive lactate measurement. The integration of AuNPs enhanced surface conductivity and provided nanoscale heterogeneity, facilitating superior signal amplification. The optimized LIG/AuNP/MIP sensor achieved an extensive dynamic detection range from 0.1 μM to 1000 μM, with an outstanding detection limit of …

Wind Tunnel Testing Of A Novel Quadrotor Design, Oliver Marius Tobisch

Mechanical & Aerospace Engineering Theses & Dissertations

This study presents the test development and aerodynamic evaluation of the Quadfoil UAV, a novel quadrotor configuration featuring a central lifting body in the form of an airfoil to enhance forward-flight efficiency. Flight tests conducted by Virginia Tech demonstrated a 25% increase in endurance and a 32% improvement in range compared to conventional quadcopters, validating the aerodynamic benefits of this design. To further investigate its performance, a dynamically adjustable angle of attack model support system was developed for wind tunnel testing, enabling precise replication of in-flight conditions. The support system, controlled via LabVIEW, adjusts angle of attack based on real-time …

Modeling The Impacts Of Disruptive Events On Driving Behaviors, Transportation Safety, And Equity: Advanced Statistical Insights From The Covid-19 Pandemic, Xiaomeng Dong

Civil & Environmental Engineering Theses & Dissertations

This dissertation aims to understand how disruptive events —particularly the COVID-19 pandemic—affect driving behaviors, transportation safety and equity by leveraging advanced statistical modeling techniques and data from Virginia. This research pursues three overarching objectives. First, it employs multigroup structural equation modeling (SEM) to uncover the complex interrelationships among risky driving behaviors, injury severity, and pandemic-related factors, delineating the mechanisms through which COVID-19 has impacted crash outcomes via changing risky driving behaviors. Second, it leverages hidden Markov models to trace shifts in safety states over the pre-, during-, and post-pandemic periods, determining whether and when safety conditions return to pre-pandemic norms. …

Investigating The Discrepancies Between Acoustic And Radar Measurements Of Water Level Using Data Analysis And Computational Modeling, Ohiedul Haque Mohammad Asad

Civil & Environmental Engineering Theses & Dissertations

Observations indicate that there is a discrepancy between water level measurements from NOAA’s acoustic gauges and radar gauges. NOAA’s acoustic gauges use a downward-looking acoustic sensor that measures the instantaneous distance from the sensor to the water level. To create a calm water surface for measurements, the sensor is placed in a PVC tube that penetrates the water surface to a certain depth. This tube is called the stilling well. In this thesis, discrepancies in water level measurements from acoustic and radar sensors were explored through data analysis and computational modeling. Specifically, the correlations between the error, which is defined …

Characterization Of Cure And Temperature Dependent Properties Of Filament Wound Composite Structures, Aaron Riley Sinkler

Mechanical & Aerospace Engineering Theses & Dissertations

Residual stress development in filament wound composites presents a critical challenge for the fabrication of thick composite structures exposed to elevated temperatures during operation. This study focused on determining temperature and cure dependent material properties to aid in understanding the residual stress build-up during the cure. Material characterization of a filament wound composite materials was performed by investigating thermo-chemical shrinkages in resin, lamina, and bi-lamina configurations. The coefficient of thermal expansion (CTE) of both the neat resin and the fiber was measured, and the gel point and chemical shrinkage of the neat resin were investigated. A filament wound unidirectional laminate …

From Image Enhancement To Model Protection Integrating Generative Ai And Secure Learning In Computer Vision, Mohammad Shahab Uddin

Electrical & Computer Engineering Theses & Dissertations

This dissertation aims to address critical challenges in the field of computer vision and machine learning, focusing on three key areas: image translation, denoising, and model security. The research encompasses novel methodologies and models that significantly advance existing techniques. This dissertation will not only provide valuable contributions to the academic community but also hold significant potential for practical applications in domains ranging from surveillance to autonomous systems.

Consequently, this dissertation proposes three goals. First, we present new approaches for converting optical videos to infrared videos using deep learning. To apply powerful deep learning based algorithms for object detection and classification …

Nanosecond Pulsed Electric Field And Plasma Jets For Cancer Therapy, Edwin Ayobami Oshin

Biomedical Engineering Theses & Dissertations

Nanosecond pulsed electric field (nsPEF) employs nanosecond-duration, high voltage pulses to induce oxidative stress, leading to temporary or permanent damage to cells or tissue (also known as reversible and irreversible electroporation), and has been considered a promising approach for cancer therapy. In parallel to this, nanosecond pulsed atmospheric pressure plasma jets (ns-APPJs) have also shown to be effective in inactivating cancer cells or increasing sensitivity of cells to electric fields. ns-APPJs are known to generate reactive chemical agents, including reactive oxygen and nitrogen species (RONS) which induces oxidative stress resulting in cell proliferation, apoptosis, and necrosis. In this dissertation, a …

Mechanochemical Reaction Kinetics—A Theoretical Modeling And Experimental Study, Maria Dolores Masso Ramirez

Mechanical & Aerospace Engineering Theses & Dissertations

Mechanochemical reactions represent a class of chemical processes triggered by mechanical energy, widely recognized for their efficiency, solvent-free nature, and environmental benefits. They are increasingly applied in synthetic chemistry, a branch of science focused on creating new chemical compounds through controlled laboratory reactions. However, the mechanisms underlying mechanical activation remain poorly understood, primarily due to the difficulty in quantifying energy transfer during milling, where solid reactants are ground together using a ball mill. This thesis aims to bridge the gap in understanding the relationship between mechanical parameters and reaction kinetics by developing and validating a theoretical framework based on dimensional …

Multiphase Iterative Algorithm For Mixed-Integer Optimal Control, Chaoying Pei, Sixiong You, Yu Di, Ran Dai

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Mixed-integer optimal control problems (MIOCPs) frequently arise in the domain of optimal control problems (OCPs) when decisions including integer variables are involved. However, existing state-of-the-art approaches for solving MIOCPs are often plagued by drawbacks such as high computational costs, low precision, and compromised optimality. In this study, we propose a novel multiphase scheme coupled with an iterative second-order cone programming (SOCP) algorithm to efficiently and effectively address these challenges in MIOCPs. In the first phase, we relax the discrete decision constraints and account for the terminal state constraints and certain path constraints by introducing them as penalty terms in the …

The Effects Of Snow Cover On The Dynamic Pressure Of Nuclear Detonation Blast Waves, Adam Card, Andrew W. Decker

Faculty Publications

Blast pressure is the primary military targeting metric for nuclear weapons. Any local conditions that affect blast pressure have the potential for altering nuclear plans, both from defensive and offensive standpoints. Understanding the impact of snow to the blast wave, therefore, provides a benefit both to military planners and to warfighters on the ground, for any operation occurring in arctic environments. No existing data provides a quantitative description of how snow on the ground affects a nuclear detonation blast wave passing over it. Similar blast waves passing over dust have experimentally proven to enhance blast pressure in a localized region.1 …

Women Overcoming Barriers In Stem: How Mentors, Allies, And Sponsors Assist Career Trajectories In Higher Education, Leila Marie Romeo

Electronic Theses and Dissertations

This study focused on the personal narratives of women in STEM in both public and private higher education institutions within various roles. Specifically, the researcher aimed to determine the following: (a) if mentors/allies influence the career trajectories of women in STEM in higher education institutions and (b) if mentors/allies aid in the support of women in STEM in higher education institutions. The researcher used semistructured interviews with a narrative analysis to determine areas of struggle for the sample within their careers and how mentors, allies, and sponsors were present throughout their careers to help the women overcome these challenges. Data …

Peerproxy: A Webrtc Proxy For Http, Nathan Li-En Lee

Master's Theses

Advances in networking technologies have empowered individuals to easily self-host digital services such as websites and smart home systems. However, accessing these services externally often requires port forwarding, which requires manual router configuration, technical expertise in networking, and is sometimes restricted by internet service providers. Proxy-based services such as Ngrok and Cloudflare Tunnels simplify external access by using publicly hosted proxy servers, but introduce increased infrastructure costs and privacy concerns due to reliance on third-party servers that can inspect or store traffic.

This thesis presents PeerProxy, a novel framework that simplifies access to self-hosted web services without manual network configuration, …

Hybrid Machine Learning And Comparison Error Minimization For Frequency Domain-Based Rapid State Estimation In Structures Subjected To High-Rate Boundary Change, James Scheppegrell

Theses and Dissertations

Dynamic forces and evolving structural boundary conditions pose challenges for various structural systems such as aircraft, orbital infrastructure, and energy harvesting devices. The design, evaluation, and functionality, of such systems can be aided through the collection and analysis of data. However, real-time decision-making for systems experiencing high-rate changes can pose unique challenges, if assessments are to be made accurately and rapidly enough to be relevant. In cases where the systems are well-defined and thoroughly understood, monitoring the frequency response can be instrumental in determining the state of structures subjected to high-rate structural boundary condition changes. This study focuses on investigating …

Investigation Of Shear Modulus And Material Damping Of A Lightly Cemented Silty Sand Representing Offshore Soil, Joshua Jeanjaquet

Theses and Dissertations

Offshore structures remain highly relevant, making the dynamic characterization of offshore soils critical. Since many offshore soils are cemented, understanding their response to dynamic loads is essential for developing accurate models that improve the reliability and cost-effectiveness of offshore structure designs. This study examines the impact of cement content on shear modulus, shear modulus reduction, shear wave velocity, and material damping of lightly cemented fine silty sand. A series of Resonant Column and Torsional Shear tests were conducted. The results were analyzed and compared to existing literature. The modified hyperbolic model was proposed to characterize the shear modulus and damping …

Assessing The Feasibility Of Transportable Nuclear Reactors: A Radiological Risk Case Study, Robert John Demuth

Theses and Dissertations

The feasibility of a truly transportable nuclear reactor presents significant radiological challenges that must be addressed to ensure compliance with regulatory limits and operational safety. This study evaluates the radiological constraints associated with the transportability of the Transportable Helium-cooled One-megawatt Reactor (THOR), focusing on neutron activation, shielding performance, and external radiation exposure. Using advanced radiation transport and activation modeling within the SCALE framework, a comprehensive analysis was conducted to quantify dose rates during operation, post-shutdown, and transport. A key aspect of this work involved assessing activation products in core materials, auxiliary components, and surrounding environments to determine their contribution to …

Understanding Water Washing Needs Of Hydrochar Generated From The Hydrothermal Carbonization Of Food Wastes To Establish Minimum Post-Processing Needs For Soil Amendment Application, Neve Renee Steger

Theses and Dissertations

Hydrothermal carbonization (HTC) is an advantageous and potentially environmentally beneficial approach for the conversion of wet biomass and waste streams into a value-added solid product referred to as hydrochar. Although hydrochar composition and properties generated from the carbonization of a variety of feedstocks have been well studied, there is a need for understanding whether hydrochar requires further refinement and/or treatment prior to being used in environmental applications, particularly when using the hydrochar as a soil amendment. Understanding the need for and extent of hydrochar post-treatment is critical in identifying environmentally beneficial and economically attractive strategies for hydrochar use. In this …

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 …

Control Of Industrial Robots Based On Artificial Intelligence, Bryan Lara Medrano

Open Access Theses & Dissertations

Industrial robots are vital in developing smart factories, creating the need for more efficient and modern control systems. As a result, investigators and scholars are dedicating great effort to advancing this field et al. [27]. Literature showcases significant progress in various areas, including the control of articulated arms and advancements in human-robot interfaces, self-decision-making, object recognition, decision-making, and routing planning. This manuscript describes a novel technique for predicting the movement of a robotic arm based on artificial neural networks. We have implemented an artificial intelligence method based on artificial neural networks to analyze the possible routing of a robotic arm …

Turbulence Numerical Simulation Of Flow Characteristics Of Laval Nozzle Top Blow Jet, Ai Liang Chen, Yao Liu, Zi Biao Wang, Huan Wu Zhan, Xue Xian Jiang, Feng Long Sun, Jiann Yang Hwang, Xi Jun Zhang

Michigan Tech Publications

The turbulent characteristics of the top-blown Laval nozzle and the influence of pressure and Mach number were studied through numerical simulation. With 2.72% error between the results and the empirical formula, the results are reliable. Nozzle fluid is influenced by pipe structure, causing pressure and density to drop as speed increases. Differences in pressure and velocity between the jet and surrounding gas lead to jet velocity attenuation, flow expansion, deflection, and eddy currents. The optimal top blowing pressure is 0.6 MPa, and the center velocity and width of the jet are 345 m/s and 0.124 m, respectively, at 20De (De …

Aimr-Brainstorm: Ai-Enhanced Interactive Mixed Reality For Collaborative Ideation, Yuchuan Ma

Dartmouth College Master’s Theses

This study investigates the potential of an AI-enhanced Mixed Reality (MR) brainstorming system, named AIMR-Brainstorm, in comparison to traditional sticky notes for creative ideation. By integrating real-time idea extraction through ChatGPT with immersive, physics-based visualizations, the system aims to transform analog brainstorming workflows into dynamic, interactive digital experiences. Using a within-subject experimental design, 30 participants engaged in paired brainstorming sessions with both AIMR and sticky notes. Quantitative measures of efficiency, engagement, creativity, and user satisfaction were collected through between-session and post-study surveys, while qualitative feedback provided additional insights into user experiences. Conclusively, while traditional sticky notes were generally preferred for …

Underlying Mechanisms Of The Effect Of Microfines Of Manufactured Sand On Non-Linear Structural Build-Up Of Cement Paste, Jiang Zhu, Jiaping Liu, Kamal H. Khayat, Xin Cheng, Wei Zhao, Zhen Li, Xin Shu, Yongbo Huang

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The rheological properties of cement-based materials made with manufactured sand vary with the content and physio-chemical properties of microfines in the sand. However, the evaluation of rheological properties regarding the structural build-up at early-age hydration remains challenging for the cementitious materials prepared with different manufactured sands, due to complicated underlying structuration mechanisms. This paper studies the effect of disparate microfines of different manufactured sands on the non-linear growth of static yield stress of cement pastes at rest. The paste mixtures were prepared with 0.40 and 0.275 water-to-cement mass ratio (W/C) and had a fixed mini-slump flow of 240 ± 5 …

Ai, Blockchain, And Autonomous Innovation : Charting The Future Of Intelligent Enterprises, Shubham Gupta

Harrisburg University Other Works

In today’s digital economy, artificial intelligence (AI) and blockchain are twin forces driving transformative change. AI and blockchain each rose to prominence on their own, but together they hold the promise of revolutionizing how businesses operate and create value. AI systems can analyze massive datasets, automate complex decisions, and even mimic human learning and reasoning. Blockchain technology, on the other hand, enables secure and tamper-proof transactions by distributing records across a network, ensuring transparency and trust without relying on a central authority. The convergence of these technologies is ushering in new possibilities for automation, smarter decision-making, and secure digital transactions …

Rookies To Aces: Investigating The Intuitiveness Of Pilot Interaction For Operating Evtol Aircraft, Shivani J. Patel

Doctoral Dissertations and Master's Theses

Electric Vertical Take-Off and Landing (eVTOL) aircraft introduce unique movement dimensions beyond traditional fixed-wing and rotor-wing aircraft, requiring novel control interfaces for pilot operation. This study examines the compatibility of gesture-based control movements across participants with varying flight experience levels. This study included a total of 60 participants across four groups; novices (no real or virtual flight experience, n=30), flight simulator gamers (n=10), fixed-wing pilots (n=10), and rotor-wing pilots (n=10). Participants viewed eighteen simulated first-person eVTOL aircraft movements (e.g. pitch, roll, yaw, heave, translations) assessing their intuitive gesture inputs for the different aircraft motions. Additionally, they were asked to sketch …

Framework For Integrating Industry Knowledge Into A Large Language Model To Assist Construction Cost Estimation, Prashnna Ghimire

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

The construction industry generates a large amount of data across projects produced by digital devices, tools, and methods, and this volume is rapidly increasing. However, the industry lags behind in adopting data-driven technologies. On the other hand, the rapid advancement of generative AI (GenAI) in recent years, especially state-of-the-art large language models (LLMs), shows great potential and has been increasingly adopted in many industries; however, the construction industry is behind in adoption. While academic studies have proposed various machine learning applications for construction, industry implementation has lagged due to a disconnect between these proof-of-concept developments and practical industry needs. Also, …