Engineering Commons^™

Computational Fluid Dynamics Based Optimization Method Applied To Hydrokinetic Turbine Devices, Stuart Glenn Fletcher

Graduate Theses and Dissertations

This thesis presents a computational investigation of optimal kinematic operating parameters governing various hydrokinetic turbines (HKT) systems for the use of power generation within river and tidal environments. Two separate studies are performed. The first study investigates optimal cycle parameters for simple and complex kinematic modes governing the motion of oscillating foil energy harvesters (OFEH). An iterative gradient-ascent optimization method is used to search for local efficiency optima based on an initial set of kinematic parameters. To search the operational space for up to eight degrees of freedom (DOF), a maximin space filling condition was implemented to efficiently compute initial …

Validation Studies Of A Dynamic Hybrid Rans-Les Turbulence Modeling Strategy For Cfd Simulation Of Gas Turbine Component Film Cooling, Cole Simmonds

Graduate Theses and Dissertations

Computational prediction of the flow physics associated with gas turbine film cooling is important for ensuring effective heat transfer design. These flow fields are highly turbulent and anisotropic, making the accuracy and efficiency of the chosen turbulence model an important aspect of performing high quality computational fluid dynamics (CFD) based analysis. Current industry standard Reynolds-averaged Navier-Stokes (RANS) turbulence models such as RANS k-ω SST, while computationally efficient, are subject to relatively high levels of uncertainty in their ability to predict these turbulent flow fields. In contrast, high fidelity methods such as Large Eddy Simulation (LES) are computationally very expensive, while …

Reverse Design Of Solid Rocket Grain Geometry, Yechan Kang

Master's Theses

The reverse design of solid rocket motors remains a challenging process due to the nonlinear relationship between the grain geometry and the internal ballistics. The reverse design process involves obtaining an optimal grain geometry given a target performance curve set by mission requirements, which is the inverse problem of the forward design. The purpose of this study is to assess the validity and implementation of neural network and simulated annealing algorithms to perform the reverse design process. A modified phase field model of the eikonal equation is derived to simulate the evolution of combustion surfaces over time, enabling burn back …

Using Scenario-Based Design Activities To Explore Sociotechnical Thinking In Engineering Professionals, James M. Whealan

Master's Theses

Sociotechnical thinking is the ability to recognize the interconnectedness of both technical and non-technical dimensions such as environmental, economic, social, cultural, and political factors. Although traditional engineering curriculum often emphasizes technical knowledge and skills, research suggests that engineering work is inherently sociotechnical. While sociotechnical thinking is a critical engineering skill, relatively little is understood about the nature of it or the different aspects comprised within it. To that end, this study addresses the following research question: What sociotechnical factors do engineering professionals consider in a collaborative scenario-based design activity? To answer this question, we conducted a qualitative study of engineering …

Time-Domain Symmetrical Components For Detection And Analysis Of Unbalanced Faults In Three-Phase Systems, Ryan Pospichal

Master's Theses

Unbalanced faults in three-phase power systems degrade performance, increase losses, and threaten equipment reliability. Traditional frequency-domain approaches using phasor analysis and symmetrical components offer valuable steady-state insights but respond too slowly for transient or rapidly changing conditions. This thesis investigates time-domain symmetrical components (ISCs) as a faster, physically interpretable method for detecting and analyzing unbalanced faults directly from instantaneous voltages and currents. Two ISC computation techniques were developed and compared: a polar-form method, applying one-third and two-thirds cycle time delays, and a rectangular-form method, which achieves equivalent phase shifts using only a quarter-cycle delay. Simulations in Microsoft Excel verified both …

Development Of A Kytc Highway Geometric Design Workshop, Jill Asher, Jeff Jasper, Travis Thompson, Chris Van Dyke

Kentucky Transportation Center Research Report

In-depth knowledge of geometric design principles is a prerequisite for delivering road projects that provide safe and efficient multimodal mobility for all users. Historically, Kentucky Transportation Cabinet (KYTC) early-career design staff arrived at the agency with little design experience. The agency has relied on a combination of short courses and mentorship provided by experienced personnel to bring early-career design staff up to speed on design best practices. However, this approach to training carries limitations. Employee turnover and imposing workloads make it challenging for early- and even mid-career design professionals to receive guidance from seasoned designers who have long tenures at …

The Importance Of Leader-Member Exchange And Psychological Contracts In Highly Qualified Researchers, Robin L. Ingerick Dba

Theses & Dissertations

This study examined the significance of the relationship between leader-member exchange (LMX) and psychological contracts in United States-based research organizations. When the organization-manager-employee relationship deteriorates, psychological contract breaches can occur, negatively affecting employee outcomes and the organization's financial success and stability. Existing knowledge highlights several factors that influence relationships, including reciprocated treatment, work behaviors and reactions, trust, professional respect, affect, mutual interaction, work autonomy, communication, job satisfaction, and fulfillment. The study sought to determine to what extent is there a predictive relationship between LMX and psychological contracts (employee obligations, employer obligations, fulfillment, and contract transitions) of highly qualified United States-based …

Data-Driven Evaluation Of Sustainable Waste-To-Energy Pathways For Intelligent Urban Systems, Izech Brian O. Edwin, King Harold A. Recto

Electronics, Computer, and Communications Engineering Faculty Publications

The handling of municipal solid waste (MSW) in swiftly urbanizing Philippine cities poses intricate energy and governance challenges. In Baguio City, reliance on landfills has reached critical levels due to diminishing capacity, rising transport costs, and opposition to trash transfers by nearby LGUs. Although shaped by unique topographical and governance constraints, Baguio’s situation reflects issues faced by other rapidly growing Philippine cities; therefore, analyzing it offers insights for national MSW decision-making. This study applies a triple bottom line (TBL) framework to assess three management scenarios: (1) Status Quo, where all MSW is landfilled with no energy recovery; (2) Landfill with …

Engineering Risk And Indigenous Resilience Toward Intelligent Decision Support For Mining In Ancestral Lands, Izech Brian O. Edwin, King Harold A. Recto

Electronics, Computer, and Communications Engineering Faculty Publications

Mining within ancestral territories reveals an ongoing conflict between technical viability and Indigenous consent. This collaborative study, conducted by an engineering scholar and a policy researcher of Indigenous heritage in Benguet among the Ibaloi and Kankanaey peoples, investigates how risk transparency and policy alignment can bridge existing divides, while formulating principles applicable to other Indigenous mining contexts. The study provides an initial evaluation of the feasibility of a proposed large-scale mining operation within a risk-informed, data-driven governance framework. Three elements of engineering risk were assessed utilizing literature-derived and proxy parameters: (1) Land degradation is indicated by a Soil Productivity Index …

Multi-Cater Pack Heat Sealer, Ivan Medina-Zepeda, Laurent Hirakata, Donovan Furtado, Cody Ngan

Mechanical Engineering

The Multi-Cater Pack Heat Sealer was developed to support Achievement House, a non-profit organization that employs adults with intellectual and physical disabilities and is facing increasing demand for sealed cater packs. Existing single-pack sealers limited both throughput and accessibility, which led to the creation of a 3D printed attachment for a 40-inch impulse heat sealer. The attachment allows nine packs to be sealed at the same time and includes a tray-style trapdoor that allows for quick unloading. The need for accessibility and usability guided the design throughout the process. Alignment guides improve placement consistency, and the ergonomic layout accommodates both …

Water Bottle Lid Co Detector, Zeke Bukovansky, Jake Siegel, Jack Wisegarver, Cody Rudman

Mechanical Engineering

This project introduces a portable carbon monoxide detector integrated into a water bottle lid to give users a simple way to stay aware of CO exposure in daily life. The design packages an electrochemical sensor, onboard electronics, and clear visual and audible alerts into a compact form that fits standard bottles. By embedding sensing into an object people already carry, the device offers a practical path toward reducing unrecognized CO risks and improving personal safety.

Investigating The Efficiency Of Ingan P-N-P-N Homojunction Solar Cells, Moath Alhejji, Mohammad Alavijeh, Jacob Kupernik, Mirsaeid Sarollahi, Abbas Jammali, Seyed Taghavi, Reem Alhelais, Md Hel Uddin Maruf, Morgan Ware

Electrical Engineering and Computer Science Faculty Publications and Presentations

This research investigates the development of a novel p-n-p-n homostructure solar cell, through semiconductor simulations using the Nextnano software. InGaN was used as a model system in order to achieve a bandgap with optimized efficiency for a p-n homojunction solar cell. By increasing the uniform doping concentration from 1.5*10(16) cm(-3) to 1.5*10(17) cm(-3), the open circuit voltage (V-oc) increased while the short-circuit current density (J(sc)) decreased, as expected in simple p-n junctions. The p-n-p-n structure achieved a peak efficiency of 32.91% at a doping level of 6.5*10(16) cm(-3), a similar to 7% improvement over a conventional p-n junction's 25.31% efficiency …

The Equity Implications Of Pecuniary Externalities On An Electric Grid, Charles Sims, Gasser G. Ali, J. Scott Holladay, Tim Roberson, Chien Fei Chen, Islam H. El-Adaway

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The adoption of rooftop photovoltaic (PV) systems can create upward pressure on retail electricity rates as utilities are forced to spread their fixed costs of generation and transmission across a smaller customer base. Since high-income households are more likely to purchase PV systems, low-income households may be disproportionately impacted by these rate increases. Using a novel combination of agent-based computational economic modeling and a choice experiment of rooftop solar adoption, we show how this pecuniary externality between low- and high-income customers increases low-income electricity bills by 10% in an area with some of the highest poverty rates in the United …

Position Sensor Offset Fault Calibration In Speed-Regulated Pmsm Drives, Ujala Anuradhi Maha Gamage

Masters Theses

Speed regulation of electro-mechanically actuated systems is common across broad application segments, including industrial and residential sectors. The increasing demand for efficient energy conversion has made permanent magnet synchronous machines (PMSM) a preferred choice in modern applications. Vector controlled PMSMs in speed regulation mode being the dominant form of control, accurate speed and position measurement is crucial. However, a misalignment in the position sensor with respect to the true rotor zero position in speed regulated PMSM drives leads to inefficient energy conversion with the possibility of unstable motor behavior. The considered position sensor offset error fault, under severe fault modes, …

Bridging The Gap Between Network Science And Network Systems To Identify And Mitigate Cyber Risk: Identify And Mitigate Backdoor Attacks On Graph Neural Networks And On Complex Systems, Sabah Ettahri

Electrical & Computer Engineering Projects for D. Eng. Degree

This doctoral project aims to bridge the gap between graph theory and network science to identify and mitigate cyber risk, represented as a CY-Triangular Network that connects different networks. The CY-Triangular Framework is a cybersecurity system that integrates graph theory and network science through an interoperable learning approach. The objective of this project is to bridge the gap between two domains: network science and network systems. Accordingly, it examines one representative network from each field, focuses on a complex system network, and explores Graph Neural Networks (GNNs). The connection between these domains lies in graph theory. This research demonstrates that …

Comparison Of The Recent Icrp Occupational Intakes Of Rradionuclides Series To Annual Limits On Intake (Ali) In The United States For Select Radionuclides, Aidan B. Barker

All Theses

Dose coefficients (DCs) and secondary limit values (such as the annual limit on intake [ALI] and derived air concentration [DAC]) are useful and convenient quantities in radiation protection (RP) for estimation of radiological dose and the practical application of dose limits. DCs link radioactivity intake to dose while secondary limit values express a dose limit in terms of the type and extent of exposure. The International Commission on Radiological Protection (ICRP), an international organization which provides guidance and recommendations for RP, calculates, tabulates, and updates DCs following new findings and updated knowledge relevant to dose determination (e.g. improved human biokinetics, …

Teachers Of Students With Visual Impairments (Tsvis) Assistive Technology (At) Competencies: An Update Study, Benjamin Kendall Lytle

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

Assistive technology (AT) is essential for supporting access, independence, and learning among students with visual impairments. Teachers of students with visual impairments (TSVIs) are expected to integrate AT into instruction and ensure their students are prepared for academic, social, and workforce demands. The original list of 111 AT competencies for preservice TSVIs, developed by Smith et al. (2009), provided an important foundation but has not been revised despite significant technological advances over the past decade. Outdated competencies risk limiting teacher preparation programs and leaving educators underprepared to address the realities of today’s classrooms. A revised and streamlined competency framework is …

A Comparative Analysis Of Complete Streets And Multimodal Transport Approaches: Implications For Sustainable Urban Mobility In Lincoln, And Global Contexts, Oliva Richard Kilyenyi

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Movement of people and goods in urban areas through different modes of transportation including walking, cycling, public transit and by autos is termed as urban mobility. Urban mobility presents significant environmental, social, and economic challenges for cities worldwide as they grapple with the impacts of conventional transportation systems, particularly in North America context where car-centric planning approaches has dominated urban developments since 1950s. Car-centric dominance is 80% in North American Metropolitan areas (Manaugh et al., 2015). The impacts of these conventional systems include greenhouse gas emission emissions contributing approximately 24% of global carbon dioxide (CO₂) emissions, air pollution …

Cattlefever: An Automated Cattle Fever Estimation System, Trong Thang Pham, Ethan Coffman, Beth Kegley, Jeremy G. Powell, Jiangchao Zhao, Ngan Le

Electrical Engineering and Computer Science Faculty Publications and Presentations

Farmers face the critical challenge of monitoring cattle well-being for both ethical and economic success, relying on signals like body temperature and facial expressions to assess their animals' health. However, these indicators have traditionally relied on human observation with manual measurement, which is time-consuming and subjective. Despite this clear need, no automated system currently exists for monitoring cattle body temperature, and available datasets remain limited in scope. To address these challenges, we make two key contributions: (i) We introduce CattleFace-RGBT, a novel RGB-Thermal (RGB-T) Cattle Facial Landmark dataset consisting of 2,300 paired RGB and thermal images (4,600 images in total), …

Enhancing Tribological Performance Of Graphite Coatings Through Spray Deposition And Adhesion-Promoting Polydopamine Underlayers, Adedoyin Ayomide Abe

Graduate Theses and Dissertations

Graphite is a widely studied solid lubricant valued for its low friction and layered structure. However, its application as a durable coating remains constrained by poor adhesion to metal substrates and limited wear resistance under sliding. This dissertation presents a systematic approach to overcoming these limitations by integrating deposition process optimization with surface chemistry modification to develop scalable, high-performance graphite coatings. Unlike many prior studies that focus on polished or idealized surfaces, this work targets steel substrates with elevated roughness levels (Sa ≥ 1 μm), aligning with conditions found in practical engineering components. The first phase of research begins by …

Rapid Construction Of Short Gap Crossings Using Indigenous Timber, Jack Everett Hamburger

Graduate Theses and Dissertations

This thesis examines multiple design options for constructing short span crossings for the military using indigenous timbers. Using indigenous timbers allows for a significant reduction in resources that must be brought into a site for construction. Construction time is minimized by optimizing the steps to convert indigenous timber into structural members for use as timbers in a short gap crossing. A major objective during this thesis study was to examine approaches for maximizing timber strength for design purposes and reduce timber weight for handling purposes. Wood strength and wood weight are highly dependent on moisture content. Decreasing moisture content addresses …

Extreme Bandgap Al0.63Ga0.37N Quasivertical Schottky Barrier Diodes With A High Baliga Figure Of Merit Of 630 Mw Cm−2, Abdullah Al Mamun Mazumder, Shahab Mollah, Kamal Hussain, Abdullah Mamun, Seongmo Hwang, Tariq Jamil, Grigory Simin, Asif Khan

Faculty Publications

"Extreme bandgap n-Al_0.63Ga_0.37N quasi-vertical Schottky barrier diodes (SBDs) with doping densities of ≈8 × 10¹⁷cm⁻³ (Sample A) and ≈2 × 10¹⁷cm⁻³ (Sample B) are grown on an AlN/sapphire substrate using metalorganic-chemical vapor deposition (MOCVD). Sample A achieves a high forward current density of ≈59.5 kA cm⁻² at 10 V with an I_ON/I_OFF ratio of ≈10⁸ (calculated from the forward current at + 3.8 V and the reverse current at −1 V) and an ideality factor of 2.8. Sample B has a forward current …

Small Laser-Textured Dimples For Improved Tribological Performance Of Cocrmo In Artificial Hip Joints, William Basore Bennett

Graduate Theses and Dissertations

Total hip replacement is a highly successful surgical intervention that restores mobility and improves quality of life for patients with severe joint degeneration. However, the long-term durability of artificial hip joints remains limited by tribological challenges, particularly wear-related failures that can lead to osteolysis and revision surgeries. In metal-on-polyethylene bearing systems, reducing friction and wear at the interface between cobalt–chromium–molybdenum (CCM) femoral heads and ultra-high molecular weight polyethylene (UHMWPE) liners is critical to extending implant lifespan. Laser surface texturing has emerged as a promising technique to improve tribological performance by introducing micro-dimples that enhance lubricant retention and reduce asperity contact. …

Multi-Criteria Decision-Making For Sustainable Design: Stakeholder Prioritization And Methodological Comparison In Solar And E-Bike Applications, Swagath Madhu Gowda

All Theses

This thesis focuses on using Multi-Criteria Decision-Making (MCDM) methods to support sustainable product design by addressing the trade-offs between environmental, economic, and social goals. The research is presented through two studies that demonstrate how both subjective and objective decision-making approaches can guide sustainability evaluations.

The first study applies the Analytic Hierarchy Process (AHP) to assess residential solar panels by incorporating stakeholder perspectives from sustainability experts, end users, and industry professionals. Using Life Cycle Sustainability Assessment (LCSA) data, this study identifies how different stakeholder groups prioritize sustainability criteria and applies Aggregation of Individual Priorities (AIP) to combine their judgments. A one-at-a-time …

Optimal Network Maintenance And Restoration: Applications And Algorithms, Nayan Chakrabarty

Graduate Theses and Dissertations

In this dissertation, we consider three types of network optimization problems. In Chapter 1, we consider a network maintenance problem which focuses on time-based redeployment of multi-class nodes for reliable wireless sensor network coverage. Whereas previous research on time-based node redeployment assumes nodes are identical with respect to time to failure, we use multiple classes of sensor nodes to represent a scenario where nodes’ times to failure are dependent on positioning in the network. We propose a partial survival signature (PSS) approach for estimating area coverage reliability under a given time-based redeployment policy, where the PSS is estimated by Monte …

Advancements In Visualization, Post-Processing And Ai-Enhanced Modeling Of Multi-Scale Micromechanics For Composite Materials, Joao Guilherme Brites Rei

Masters Theses

This study addresses some of the primary deficits of a localization/homogenization workflow for composite materials by focusing on the visualization and enhancement of models based on GMC and HFGMC, with emphasis on their implementation within the NASMAT ecosystem.

This thesis details the development of two dynamic, ParaView-based plugins that convert large hierarchical simulation outputs into interactive insights. While NASMATDiscreteElement systematizes RUC creation with transparent parametrization in a reproducible GUI, NASMATExplorerRUC enables the inspection of deeply nested datasets through accurate cell picking and synchronizes comparisons between parent and child views. Additionally, a shallow U-Net neural network is optimized on HFGMC data …

Editable 4d Gaussian Splatting: Scalable And Consistent Video Editing Via Uv-Texture Decomposition, Shuai Lyu

All Theses

Dynamic 3D videos are now widely used in VR, AR, and telepresence, where users often want to change the style or appearance of objects such as clothing over a whole sequence. However, editing such dynamic 3D content is still hard, because appearance, geometry, and motion are tightly coupled, so even a simple color change must stay consistent in all views and at all time steps. Existing editing methods based on 4D Gaussian Splatting often work in a frame-by-frame way, which is slow and makes it difficult to keep temporal and multi-view consistency.

This thesis proposes Editable-4DGS, a representation-centric framework that …

The Iron Pyramid: Expanding The Iron Triangle To Integrate Safety As A Fundamental Dimension Of Construction Success, Laura Cooley

All Theses

For more than fifty years, construction project success has been judged by staying on schedule, remaining within budget, and completing the planned scope of work—an approach commonly known as the “Iron Triangle” (Barnes, Ph.D., 2006). While these measures are important, they do not capture the full range of factors that determine whether a project truly succeeds.

This study introduces the “Iron Pyramid” (Cooley, 2025), a model that expands the traditional framework by adding a fourth dimension: safety. Safety is understood not simply as regulatory compliance or the absence of injuries, but as a holistic construct encompassing project culture, leadership practices, …

Digital Solutions For Bridging Language Barriers: Designing And Testing An App For Construction Spanish Safety Communication On Construction Jobsites, Adrian Cappella

All Theses

Language barriers between English-speaking supervisors and Spanish-speaking workers create safety risks on U.S. construction jobsites. Hispanic workers face higher injury and fatality rates, with miscommunication being a major contributing factor. Existing translation tools lack the accuracy, cultural context, and jobsite relevance needed for effective safety communication.

In this study a mobile application with construction-specific safety phrases in English and Spanish was designed and field tested. The research included a literature review, phrase collection and validation with industry experts, application development and design with a computer science collaborator, and usability testing with supervisors and workers. Surveys and field trials measured navigation, …

Advancements In Sinkhole Remediation: Field Data-Driven Sinkhole Grout Volume Prediction Model Via Machine Learning-Based Regression Analysis, Bubryur Kim, Yuvaraj Natarajan, K. R. Sri Preethaa, V. Danushkumar, Ryan Shamet, Jiannan Chen, Rui Xie, Timothy Copeland, Boo Hyun Nam, Jinwoo An

Civil Engineering Faculty Publications

Sinkhole formation poses a significant geohazard in karst regions, where unpredictable subsurface erosion often necessitates costly grouting for stabilization. Accurate estimation of grout volume remains a persistent challenge due to spatial variability, site-specific conditions, and the limitations of traditional empirical methods. This study introduces a novel machine learning-based regression model for grout volume prediction that integrates cone penetration test (CPT)-derived Sinkhole Resistance Ratio (SRR) values, spatial correlations between CPT and grouting points (GPs), and field-recorded grout volumes from six sinkhole sites in Florida. Three data transformation methods, the Proximal Allocation Method (PAM), the Equitable Distribution Method (EDM), and the Threshold-based …