Digital Commons Network^™

Bone Void Filler Materials For Augmentation In Comminuted Fractures: A Comprehensive Review, S. Sina Mohammadi, Sunjeev S. Phull, B. Sonny Bal, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

Comminuted fractures, characterized by multiple bone fragments, present significant challenges in orthopedic surgery. Effective treatment often requires augmentation techniques to enhance fixation stability and promote bone regeneration. This review explores the application of bone void filler materials, including autografts, allografts, polymethyl methacrylate (PMMA), and synthetic bone substitutes such as calcium phosphate ceramics and bioactive glass, in managing comminuted fractures. Autografts are the gold standard due to their superior osteogenic potential but are limited by donor site morbidity and availability. Allografts mitigate these issues but face concerns regarding immunogenicity and reduced biological activity. PMMA, widely used for structural augmentation, provides immediate …

Local Hydrodynamics And Phase Distribution In Large-Scale Trickle Bed Reactors Using Multi-Detector Γ-Ray Densitometry, Sebastián Uribe, Ahmed Jasim, Saba A. Gheni, Nora Selem, Nouhaila Filali, Tiberiu M. Leib, Sourav Sengupta, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

This study presents a new approach of using gamma ray computed tomography (CT) in a form of arc multi-detector γ-Ray Densitometry (Arc MD-GRD) Technique where it measures the line averaged holdups of the phases which are projected on the diameter of the column to obtain their diameter profiles. This technique then was used to investigate the diameter profiles of the phases' holdups in a 12-inch diameter trickle bed reactor (TBR) using sulfur hexafluoride (SF6) as the gas phase to represent to a certain extent the industrial higher density of the used gas phase due to either the type of the …

Unlocking The Potential Of Copper Sulfide Tailings As A Secondary Source For Tellurium And Precious Metals: A Comprehensive Characterization Study, Fardis Nakhaei, Lana Alagha, Gary Wyss

Mining Engineering Faculty Research & Creative Works

This study investigated historical copper sulfide tailings as an unconventional source of tellurium (Te), gold (Au), and silver (Ag). Advanced analytical studies were conducted to determine the geochemical and mineralogical properties of the tailing samples. The results showed that tetradymite (Bi2Te2S) was the predominant Te-bearing mineral, while hessite (Ag2Te) was a minor Te carrier, both notably occurring within fine-grained (< 8 μm) inclusions in pyrite. Gold was present as native Au, electrum (Au-Ag), and within complex silver tellurides hosted primarily in chalcopyrite and pyrite. Froth flotation studies showed that the 180 to 38 μm size range was the optimum feed size that yielded recoveries of 59 %, 37 %, and 27 % for Te, Au, and Ag, respectively. These findings suggested that froth flotation is a feasible method for concentrating Te-Au-Ag-bearing phases. Given the strong association between Te, Au, Ag, and Cu, the co-extraction of these metals should significantly enhance the economic viability of tailings' processing.

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 …

Enhancing Management Of Transportation Projects: Integration Factors For Using Smart Contracts, Mariam Elazhary, Islam H. El-Adaway

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The US Department of Transportation (USDOT) delivers a wide range of infrastructure projects, backed by a fiscal year 2023 budget exceeding $100 billion. These projects face mounting pressures to meet performance, accountability, and delivery standards, driven by their dependence on public funding and their operational complexity. Transportation infrastructure presents sector-specific challenges - such as time-sensitive user disruptions, multiparty coordination, and asset intersection risks - that demand more robust, automated, and transparent project delivery mechanisms. Blockchain-enabled smart contracts have emerged as a promising solution to address these operational pain points through real-time automation, immutable data records, and decentralized transaction processing. However, …

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 …

Evaluating Crumb Rubber Modified (Crm) Asphalt As A Sustainable Binder Alternative For High-Friction Surface Treatments, Abdallah Aboelela, Alireza Roshan, Magdy Abdelrahman

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

High-friction surface treatments (HFSTs) are widely applied to improve pavement safety by enhancing long-term skid resistance. Although epoxy resins are commonly used due to their strength and durability, their high cost, susceptibility to delamination, incompatibility with substrates of flexible pavements, and adverse environmental concerns limit their long-term performance. This study presents crumb rubber modified (CRM) asphalt as a sustainable alternative binder for HFST applications. CRM binders offer high performance and compatibility with existing pavement surfaces, cost effectiveness and reduced environmental impacts as compared to epoxy binders. In addition, the binder development utilizes enhanced recycling technologies for interacting with used tire …

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, …

Advancement Of Wearable Hardware & Possible Cross-Sector Applications, Yassine Chahid, Patrick Slattery

Publications and Research

This study examines recent advances in wearable technologies including smart glasses, watches, rings, and related devices. It evaluates their applications across healthcare, manufacturing, education, and logistics. As real-time data collection, hands-free interaction, and continuous health monitoring become more prevalent, wearables are emerging as pivotal tools for both personal and professional contexts. The methodology combines a comparative analysis of current-generation devices, a review of technical specifications from manufacturer documentation, and case studies of specialized deployments, particularly in medical diagnostics, remote monitoring, and workplace efficiency. Project findings will indicate the rate at which wearable devices are moving beyond consumer fitness tracking and …

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 …

Data Center Composite Load Model Parameters’ Tuning, Mohammed Sleiman, Amirreza Sahami, Oluwatimilehin Adeosun, Nathaniel Rice, Katelyn Vance

Electrical and Computer Engineering Faculty Research & Creative Works

The vast expansion of data center campuses has created concentrated and highly dynamic electrical loads that challenge traditional transmission system planning and protection studies. This paper presents a novel approach to model the load of data centers and validate their dynamic performance in a composite-load-model (CMLD) framework.

The data center has three major modules: a static element representing the static devices and busway impedance; an electronic-based element constituting power converters such as rectifiers and inverters, associated power supplies, and a motor-based element encompassing the induction nature of chillers, fans and pumps. Each module represented equivalent algebraic and differential equations depicting …

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, …