Digital Commons Network^™

Exit Topology Effects On Low-Mach Jet Impingement, Alejandro Garcia

Theses and Dissertations

Planar PIV characterizes a low‑Mach (M = 0.05) air jet impinging normally on a plate at fixed spacing H/D = 4.0. Four nozzles of equal hydraulic diameter (D = 50.8 mm) are compared: circular, rectangular (AR 3), diamond, and elliptical (AR 2); asymmetric exits are tested in major and minor orientations. Mean velocity, azimuthal vorticity, and turbulence kinetic energy reveal that exit topology strongly modulates the stagnation footprint and shear‑layer growth. The circular jet forms the canonical toroidal wall jet and a narrow stagnation core (dₛ = 0.9D). Orienting the rectangular major axis toward the plate elongates the core to …

The Role Of Operational Context In Shaping Energy Management Portfolios: A Comparative Case Study Of Two Manufacturing Facilities, Cynthia Aranda

Theses and Dissertations

Using two facilities as illustrative examples, this research investigates how a manufacturing plant's operational and financial context may influence its investment decisions in energy-efficiency measures. This challenges the primacy of the simple payback period (SPP) as a screening tool and instead demonstrates the role of operational context in investment decision-making. To this extent, this study is anchored to a qualitative comparative case study analysis of two ITAC energy assessments for two manufacturing plants in Texas: a higher value-added aerospace MRO plant (GE Aerospace, TR0060) versus a cost-sensitive automotive stamping plant (UMP Metal Stamping, TR0061). The two cases illustrate two different …

Sub-Ghz Propagation Along Freight Trains For Wireless Onboard Communications, Dario Hinojosa

Theses and Dissertations

With the increasing length of freight trains, maintaining reliable wireless communication for onboard sensors has become increasingly challenging. Sub-GHz communication bands are a promising solution due to their long-range capability and suitability for rural railway environments. This study analyzes radio wave propagation around freight railcars to evaluate path loss and determine how antenna polarization affects wireless communication performance.

Time-domain full-wave electromagnetic simulations were performed using simplified railcar models and later validated through field testing using a vector signal generator, vector network analyzer (VNA), and spectrum analyzer. Various antenna polarization configurations were evaluated within the Sub-GHz Long Range (LoRa) frequency band …

Los Juegos De Rol Como Una Herramienta Psicoeducativa, Víctor E. Quintana Villarreal

Journal of Roleplaying Studies and STEAM

Los juegos de rol han funcionado durante mucho tiempo como un medio para compartir y crear historias en conjunto con colegas y amigos. De ellos, se desprenden también habilidades y herramientas fundamentales para la vida, por lo que un método para sistematizar estos juegos de tablero y dados a funciones educativas es necesario para potenciarlos como herramientas psicoeducativas.

La siguiente, es una propuesta planteada desde el marco constructivista para generar espacios con los juegos de rol como eje central del aprendizaje, y se relatan a través de un marco teórico, seguido de una proposición metodológica, una serie de pasos para …

Journal Of Roleplaying Studies And Steam (Jrpssteam) Vol. 5 [2026], Número 1 (Issue 1), Romano Ponce-Díaz Phd, Cristo Leon, Ivan Avila, Sarah Lynne Bowman, Kjell Hedgard Hugaas, Alexandra Schreiber Ma, Jaime Eduardo García Maya, Víctor Emmanuel Quintana Villarreal Vic Emma, Francisco Gonzalez Ing., Daniel Romero Benguigui, Antonio Roda-Martínez

Journal of Roleplaying Studies and STEAM

El presente número del Journal of Roleplaying Studies and STEAM examina la convergencia entre las prácticas lúdicas, el diseño narrativo y los procesos de mediación sociocultural en la investigación contemporánea. Las contribuciones reunidas en este número abordan el juego de rol como un dispositivo de producción de conocimiento, intervención psicoeducativa y reelaboración de representaciones culturales. Nos podemos atrever a señalar que la educación es la convergencia entre la ludología, las ciencias sociales, los estudios visuales y el análisis cultural; entendiendo a la educación como la actividad consciente e intencionada de transmitir información y conocimientos a las siguientes generaciones.

Martin Heidegger …

A Novel Approach To Creativity Assessment: Forced Pairwise Ranking With Large Language Models, Phillip R. Gregory Jr

Master's Theses

Assessing creativity at scale remains a persistent challenge in cognitive science, as human raters are costly, slow, and often inconsistent in their judgments. This thesis introduced a novel framework for automated scientific creativity assessment using forced pairwise ranking, in which fine-tuned large language models compared response pairs and determined which was more creative. Five empirical studies were conducted using Llama-2-7B and Llama-2-13B models adapted via LoRA fine-tuning and benchmarked against human scored responses from the Scientific Creative Thinking Test. A regression baseline achieved Pearson �� = .74 on the test set, matching the human inter-rater ceiling reported in the literature. …

Undergraduate Design Spine For Biological Systems Engineering And Agricultural Engineering, David Mabie, Derek M. Heeren, Deepak R. Keshwani, Heidi A. Diefes-Dux, Nicole M. Iverson, Rachel Padrnos, Greg Bashford, Taryn King, Jenna Hefley, Curtis L. Tomasevicz

Department of Agricultural and Biological Systems Engineering: Presentations and White Papers

Engineering education is undergoing a shift toward preparing graduates with demonstrated capabilities that integrate technical knowledge, durable skills, and the ability to adapt in a rapidly evolving professional landscape. This paper describes a comprehensive redesign of the undergraduate curriculum in Biological Systems Engineering (BSEN) and Agricultural Engineering (AGEN) at the University of Nebraska–Lincoln. The redesign is grounded in a “Design Spine” framework, which distributes and scaffolds design experiences across all four years of the program to support progressive development of problem solving, systems thinking, communication, and professional skills. The curriculum is organized around clearly defined capabilities and threads that connect …

Assessment Of Super Absorbent Polymer In Soybean Cultivation Under Variable Irrigation Conditions In Nebraska, Ankit Chandra, Abia Katimbo, Ronaldo Marchezan, Martha Nabaggala

Department of Agricultural and Biological Systems Engineering: Presentations and White Papers

Water limitation is a primary constraint to soybean productivity in both irrigated and rainfed systems. Soil-applied superabsorbent polymers (SAPs) have been proposed as a strategy to buffer crops against episodic drought stress; however, their physiological and agronomic performance under varying irrigation regimes remains insufficiently quantified. Here, we evaluate three biodegradable polymer formulations: broader granules (BB), original granules (OG), and powder (PWR) applied at low (17.7 lb/ac) and high (120 lb/ac) rates under full (100% ET), reduced (50% ET), and no irrigation conditions in western Nebraska. Polymer application had negligible effects under full irrigation, with yields comparable to untreated controls. Under …

2026 Spring Graduate Recognition Program, Propulsion Research Center, Robert Frederick

PRC Graduate Recognition

This program includes the graduate recognition program for spring 2026. Includes photographs, upcoming events, recent publications, and student profiles.

Introduction To The Special Issue On Computer Modeling For Future Communications And Networks, Wenbing Zhao, Pan Wang

Electrical and Computer Engineering Faculty Publications

No abstract provided.

Enhancing Reliable Performance Of Microgrids With Autonomous Control Of Distributed Energy Resources, Sahand Liasi

All Dissertations

This dissertation presents a comprehensive investigation into enhancing the reliability, efficiency, and autonomous operation of modern power networks through advanced microgrid integration and control strategies. The research addresses critical challenges across three interconnected domains: microgrid control, thermodynamic modeling of heat recovery system (HRS), and optimal distribution network reliability.

In the realm of microgrid control, this work introduces novel methodologies for grid forming inverter-based resources (IBRs). A significant contribution is the development and validation of an "Auto Frequency Change" controller, which drastically reduces microgrid synchronization time with the main grid from several minutes to approximately four seconds, with theoretical potential for …

Development And Validation Of The Ampere Scale: Measuring Adaptive And Maladaptive Perfectionism In Engineering Students, Haleh B. Brotherton

All Dissertations

Perfectionism refers to the inclination to set very high expectations for oneself, which can at times encourage personal development and at other times lead to stress and a sense of pressure. Perfectionism is widely observed among engineering students; however, instruments that distinguish adaptive striving from concern-driven tendencies in the engineering context remain limited. My study is based on the development and validation of the AMPERE (Adaptive and Maladaptive Perfectionism in Engineering) scale through a three-phase process: (I) expert review with two domain experts to establish content validity; (II) cognitive interviews with seven undergraduates to refine wording and interpretability; and (III) …

Generative Ai Of Breast Cancer Progression In Gene Expression Space, Xusheng Ai

All Dissertations

Breast cancer is one of the most common and deadly cancers in the world. Although doctors can use gene activity data to better understand different types of breast cancer, it is still difficult to identify the most important genes and to track how the disease changes over time. This is partly because gene data are very large and complex.

This dissertation develops a computer-based framework to study breast cancer using gene expression data. The work focuses on three goals: creating realistic synthetic gene data, identifying important genes linked to cancer, and modeling how breast cancer changes from normal tissue to …

Safe Control Design For Quadruped Locomotion In Unstructured Environments Using Linear Transfer Operators, Sriram Sundar Krishnamoorthy Shankara Narayanan

All Dissertations

Deploying quadruped robots in unstructured, obstacle-rich environments requires control and planning methods that remain safe and reliable despite complex terrain geometry, limited sensing, and inevitable modeling errors. This thesis develops operator-theoretic tools for safe control design of robotic systems using linear transfer operators, with a focus on quadruped locomotion in unstructured environments. The central goal is to develop a unified operator-theoretic framework for safe control design based on the Perron–Frobenius (P–F) and Koopman operators. In particular, the thesis leverages \emph{density functions} to develop safe navigation frameworks in the dual space of densities. In the operator-theoretic perspective, the P–F operator governs …

Interplay Between Phase Instability And Deformation Mechanisms In Beta Titanium Alloys In Aggressive Environments, Benjamin Elbrecht

All Dissertations

Modern designs, such as commercial jet turbines, are reliant on the high temperature performance of their constituent materials. Improvements to the strength-at-temperature of materials are critical to the continued advancement of efficiency and payload capacity in these advanced applications. This dissertation presents studies that progress towards this goal through the construction of a new experimental setup for complex temperature and force profiles that also accurately captures deformation behavior through non-contact measurements. Using this setup, studies into two specialty titanium alloys were executed: discovering the microscopic mechanisms responsible for the macroscale behavior and testing in conditions closely replicating aircraft turbine operating …

Baseline Cervical Intervertebral Disc Biomechanics And Implications For Allograft Preservation, Nathan F. Buchweitz

All Dissertations

Neck pain has become an increasingly common orthopaedic healthcare issue. Evidence shows that degeneration of cervical intervertebral discs (the cartilage between the spinal vertebrae in the neck) may be associated. While disc degeneration in the lumbar spine has been extensively studied in relation to low back pain, it has received less attention in the cervical spine. Biomechanically, the cervical (neck) and lumbar (lower back) regions of the spine differ in function. Lumbar discs resist a greater burden of body weight, whereas cervical discs are adapted for mobility to aid flexible head orientation. Despite these key differences, disc injury and degeneration …

A Machine Learning Framework For Early-Stage Cost Estimation Of Transportation Projects, Pritom Paul

Electronic Theses and Dissertations

To address the limitations of traditional planning-level cost estimating methods, such as reliance on statewide averages, heavy reliance on engineering judgment, and high levels of inaccuracy, this study developed two data-driven frameworks and corresponding tools. The first framework focused on resurfacing projects and used treatment-specific simple linear regression based on lane miles and geographic location. The second addressed a broader group of construction projects and used multiple linear regression with project length, route type, and right-of-way cost as key predictors. In both frameworks, the final estimates are computed by aggregating multiple estimates produced by county-, region-, and state-level models. The …

Decomposition And Spectral Characterization Of Unsteady Loads In Pulse-Jet Propulsion Testing, Cesar Benitez

Theses and Dissertations

Pulsed jet propulsion systems produce inherently unsteady forces whose time-resolved characterization is essential for performance assessment, yet the measured load signal conflates aerodynamic forcing with the dynamic response of the measurement balance itself. This thesis develops a load centered framework for the dynamic characterization of a pulsed jet system, treating the measured load fluctuation as the primary physical observable rather than attempting full true-thrust reconstruction. A single-degree-of-freedom balance model identified through ringdown testing provides the structural reference scale, yielding a natural frequency of 8.5 Hz and damping ratio of 18%. Power spectral density, phase-averaging, and synchronous–residual decomposition is applied uniformly …

Examining The Effects Of Lateral Loading On Railroad Tapered Roller Bearings, Abel David Sanchez Trinidad

Theses and Dissertations

The loading conditions experienced by freight railcar bearings vary as a function of vehicle operating conditions. Under static conditions, bearings are primarily subjected to radial loads transmitted through the wheelset. During operation, however, track irregularities, braking events, railcar load imbalances, and curving introduce complex impact, longitudinal, and lateral forces in addition to the normal radial loading. These lateral forces increase friction within the bearing raceways, which could accelerate wear and potentially lead to premature spall initiation and propagation. While prior research at the University Transportation Center for Railway Safety (UTCRS) has demonstrated that vibration signatures can be used to detect …

Detecting Sophisticated Cyberattacks On Public Water Infrastructure, Ayrton Purdy

Graduate Theses and Dissertations (2019 - present)

In recent years there has been an increasing number of cyberattacks on public water generation and distribution systems. Advanced persistent attackers could usurp sensors and control systems to contaminate public drinking water. In order to conceal their malicious activity, they can manipulate sensor data flows to give the appearance of normal activity. The compromised sensors would report normal chemical levels even though unsafe water is entering the distribution system. In response, this research proposes a multi-sensor, cross-comparison approach to anomaly detection. The proposed approach is designed to detect sophisticated cyberattacks which are not easily detectable using traditional cyber tools. The …

Developing A Framework For Microchip Design Recovery, Eric Diep

Graduate Theses and Dissertations (2019 - present)

Due to the increase in diverse chip production over the past decade, reverse engineering has become a difficult and daunting task. This research develops a methodology for microchip design recovery, seeking to validate and reproduce prior approaches to physical reverse engineering using low-cost tools and techniques. We used mechanical hardware abrasion tools and techniques to delayer and capture silicon integrated chip (IC) layout. We focused on the Mifare Classic EVl microchip, commonly implemented in public transit/transportation cards, to extract information for design recovery. The research explores limitations and advantages of mechanical abrasion and optical microscopy in context to modem chip …

Manufacturing Systems: Characteristics And Dynamics, Alan J. Fitzmorris

Graduate Theses and Dissertations (2019 - present)

This research answers three basic questions. First, what are the behaviors (dynamics) of a manufacturing system in the context of system performance? Are these dynamics best described as linear deterministic, periodic, nonlinear deterministic, or stochastic? Second, what are the complexity (chaotic) characteristics of a manufacturing system, namely the maximal Lyapunov exponent, correlation dimension, and Kolmogorov-Sinai entropy? Third, is there a relationship between complexity characteristics and manufacturing system performance? This research involves four high level steps: data analysis, system dynamics analysis, system complexity analysis, and correlation analysis. The data analyzed consists of concrete plant and shipbuilding shop time series performance data. …

Retrospective Analysis Of Implemented Project Management Within A Small-Scale Student Engineering Project: Beng Fountain Wars Team Case Study, Holli E. Jenkins

Biological and Agricultural Engineering Undergraduate Honors Theses

This honors thesis provides a retrospective analysis of how the 2025 inaugural University of Arkansas’s ASABE Fountain Wars Student Team could be improved through project management. Project commitment, early stakeholder influence, rich communication, and a detailed project plan are all attributes of successful projects, and the team’s strengths and weaknesses within these categories were determined through a team poll. After the poll was conducted, three methodologies, Agile, Hybrid, and Waterfall, were assessed to determine how they would effectively address the team’s weaknesses. A weighted objectives table was created to compare each methodology’s effectiveness across the management categories. The analysis revealed …

Enhancing Food Security In Stann Creek, Belize Using Meat Rabbits: Engineering Perspective, Lindsey Garretson

Biological and Agricultural Engineering Undergraduate Honors Theses

The purpose of this paper is to discuss the engineering perspective within the overall project of using meat rabbits to enhance food security and nutrition within Stann Creek, Belize. From the engineering perspective, the overarching goals were like the overarching project goals including the construction and materials required guide within the manual, designing potential upgrades to the design including a solar and battery system and an automatic watering system, and to design the system to be “practically sustainable” where possible. The constraints for this project included cost, the size of land dedicated for the rabbitry, and the operational and environmental …

A Baseline Study Of Artificial Intelligence Use Among Chemical Engineering Undergraduates At The University Of Arkansas, Natalie J. Erickson

Chemical Engineering Undergraduate Honors Theses

In recent years, artificial intelligence (AI) has shifted from a novel innovation to a tool used in daily life, particularly within higher education. While anecdotal evidence suggests high levels of student engagement with AI, empirical data regarding usage patterns remains limited. This baseline study investigates AI integration among undergraduate chemical engineering students at the University of Arkansas. Through an anonymous survey (N=68; comprising 20 freshmen, 14 sophomores, 16 juniors, and 18 seniors), researchers assessed usage frequency, student comfort levels, and their evolving relationship with AI tools. The findings reveal that 75% of respondents utilize AI for coursework at least once …

From Kernel To Carbon Footprint: Using Life Cycle Analysis To Teach Sustainability In Chemical Engineering, Neal Z. Kinney

Chemical Engineering Undergraduate Honors Theses

Many chemical engineering departments in the United States are currently lacking developed sustainability coursework, leaving many students without a developed understanding of topics such as life cycle analysis (LCA). [1] Therefore, there is a need for engaging and flexible educational tools that can be easily incorporated into course frameworks. This study develops an interactive learning module, expanding upon the work from Pollution Prevention Through Popcorn, a study developed by Rowan University. [2] The module combines experimental analysis of popcorn popping methods with life cycle assessment using OpenLCA to evaluate the environmental impacts of common types of popcorn packaging. Results of …

Surface-Functionalized Silica Nanoparticles For Enhanced Bioavailability In Ophthalmic Mucoadhesive Drug Delivery Applications, Kaylee M. Drake

Chemical Engineering Undergraduate Honors Theses

This study investigates the stimuli-responsive behavior of porcine gastric mucin (PGM) as a model for the conjunctival mucous membrane of the human eye to optimize mucoadhesive ophthalmic drug delivery. As a versatile biopolymer, PGM has a dynamic matrix structure that functions as a selectively permeable barrier, regulating transport across mucosal membranes. To improve drug bioavailability and retention in ocular treatments, silica nanoparticles (SiNPs) were modified with varying surface functional groups and incorporated into the mucin at different physiological pH levels to examine the resulting microstructural changes. Leveraging the amphiphilic and negatively charged characteristics of mucin, positively charged and hydrophobic SiNPs …

Design Of Aluminum-Air Battery Systems And Optimization Of Cetyltrimethylammonium Bromide And 8-Hydroxyquinoline Additives In Alkaline Electrolytes, Steve Chen

Chemical Engineering Undergraduate Honors Theses

The first portion of this thesis focuses on the design and component optimization of aluminum-air batteries to power a car for the Chem-E-Car competition. A range of separators, cathodes, and current collectors was evaluated to determine the optimal configuration for maximizing output. The resulting system consisted of 1000 series aluminum as the anode, cellulose separators saturated in 1 M potassium hydroxide as the electrolyte, and composite PVDF and graphite as the cathode. The improved batteries achieved a power density of 2.14 x 10^-4 W/cm² and were utilized for the Chem-E-Car competition. The second portion of the thesis investigates …

Electrochemical And Mechanical Evaluation Of Cellulose Acetate Electrolyte Films As A Function Of Polyetherimide And Polyethylene Glycol Additives For Supercapacitor Applications, Chase E. Golden

Chemical Engineering Undergraduate Honors Theses

Polymer electrolytes for supercapacitor applications require a balance between mechanical robustness and electrochemical performance. In this study, cellulose acetate (CA) films were modified with additives such as polyetherimide (PEI) and polyethylene glycol (PEG) to test how compositional changes influence mechanical performance, ionic conductivity, and electrochemical charge storage. Films were cast using phase inversion, soaked in a 1 M NaCl aqueous solution, and characterized using Fourier-transform infrared spectroscopy (FTIR), electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and tensile testing. Films were also evaluated based on fluid uptake for insight into electrolyte retention.

Characterizations show that the addition of PEI increased ionic …

Performance Of Zirconia-Based Catalysts For Cold Plasma-Assisted Dry Methane Reforming, Levi Pile

Chemical Engineering Undergraduate Honors Theses

This study investigates the performance of zirconia-based catalysts in non-thermal plasma (NTP)–assisted dry methane reforming (DMR) for synthesis gas (syngas) production. This work explores an alternative pathway for converting carbon dioxide and methane into valuable products under milder conditions than conventional thermal processes. Experiments were conducted in a radiofrequency plasma reactor to evaluate the effects of plasma power, feed flow rate, and reactant ratios on conversion efficiency. The performance of plasma-only conditions was compared with packed-bed systems using zirconia catalysts. Results show that plasma-only systems achieved modest conversion rates (~16.5% for CH₄ and ~12.0% for CO₂), while …