Digital Commons Network^™

Navigating Mental Health During Covid-19: Considerations Of Childhood Adversity, Pandemic Stress, And Loneliness, Linnea Rose Swanson

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

The purpose of this dissertation study was twofold. First, to determine if the addition of bullying victimization to the Adverse Childhood Experiences (ACEs) Questionnaire (Felitti et al., 1998) would result in a stronger measure of childhood adversity; second to examine the interaction between ACEs, pandemic stress, loneliness, and internalizing symptoms in a sample of young adults living in the United States during the COVID-19 pandemic. ACEs are linked to negative outcomes in adulthood including mental health problems, stress, and loneliness. During the pandemic, increased levels of stress and loneliness were associated with higher rates of internalizing disorders among young adults. …

Seasonal Comparison Of Air Quality Variables And Evaluation Of Carbon Dioxide And Particulate Measurement Period In Classrooms, Daud Nosham

Durham School of Architectural Engineering and Construction: Dissertations, Theses, and Student Research

Indoor air quality and thermal environmental variables were measured in 55 classrooms in the mid-western United States spanning a full academic year. The studied air quality and environmental factors included carbon dioxide, temperature, relative humidity, particle counts, air velocity, formaldehyde, total volatile organic compounds, carbon monoxide, nitrogen dioxide, and ozone.

Carbon dioxide and Particulate matter concentrations were measured for a four-day measurement period. Then one-day, two-day, and four-day occupied time average concentrations were calculated which were then compared statistically to figure out an appropriate measurement period for these air quality variables. Kruskal Wallis test and Wilcoxon test were used to …

Design And Optimization Of A Novel Monolithic Spring For High-Frequency Press-Pack Sic Fet Modules, Bogac Canbaz

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

Silicon Carbide (SiC) Field-Effect Transistor (FET) modules lead the way in power electronics, being superior in efficiency and robustness for high-frequency applications. The shift towards SiC from traditional silicon (Si)-based devices is driven by its superior thermal conductivity, higher electric field strength, and operational efficiency at elevated temperatures. These features are critical for the development of next-generation, grid-oriented power converters aimed at enhancing the reliability and sustainability of power systems. This research focuses on high-frequency press-pack (HFPP) SiC FET modules, addressing the primary challenge of miniaturizing SiC FET dies without compromising performance, through an innovative press-contact design essential for increased …

Charge And Strain Engineering Of Ferroic And Correlated Oxides, Yifei Hao

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

This dissertation presents a comprehensive study of the charge and strain effects on the electronic and magnetic properties of epitaxial ferroic and correlated oxide thin films and heterostructures. We perform the planar Hall effect to quantify the magnetocrystalline anisotropy (MCA) in epitaxial La_1-xSr_xMnO₃ films (x = 0.2 and 0.33) deposited on SrTiO₃ substrates. The biaxial magnetic anisotropy energy of L_0.67Sr_0.33MnO₃ is about 17% larger than La_0.8Sr_0.2MnO₃. By comparing with the theoretically predicted values, we have decoupled the doping and strain effects on …

Next-Generation Crop Monitoring Technologies: Case Studies About Edge Image Processing For Crop Monitoring And Soil Water Property Modeling Via Above-Ground Sensors, Nipuna Chamara

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

Artificial Intelligence (AI) has advanced rapidly in the past two decades. Internet of Things (IoT) technology has advanced rapidly during the last decade. Merging these two technologies has immense potential in several industries, including agriculture.

We have identified several research gaps in utilizing IoT technology in agriculture. One problem was the digital divide between rural, unconnected, or limited connected areas and urban areas for utilizing images for decision-making, which has advanced with the growth of AI. Another area for improvement was the farmers' demotivation to use in-situ soil moisture sensors for irrigation decision-making due to inherited installation difficulties. As Nebraska …

Surface Chemistry Of Femtosecond Laser Processed Surfaces, Graham Kaufman

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

Micromachining and surface functionalization with femtosecond lasers is a rapidly developing technology in the field of materials and interfacial sciences due to its flexibility towards materials, tunability in surface features, and prospects for scalability. Many interfacial applications have been shown to be enhanced with femtosecond laser-induced surface texturing including two-phase heat transfer, antimicrobial properties, electrochemical systems and more. However, without ideal surface chemistry, the enhancements cannot be optimized for a given application. Surfaces functionalized by femtosecond lasers tend to have transient surface chemistries when exposed to the atmosphere, changing important interfacial properties like the interaction of the solid surfaces and …

Charging Forward: A Comparative Analysis Of Facilitators To Electric Vehicle Adoption In Three U.S. States, Abigail Schroeder

Department of Environmental Studies: Undergraduate Student Theses

Electric vehicles (EVs) are a way to reduce greenhouse gas emissions from transportation, but low consumer adoption rates present a challenge. In order to understand what factors may facilitate EV adoption, a comparative analysis of three U.S. states was performed. These states have the highest rates of EV adoption in the country. Thus, studying them provided insights into what may make EV adoption successful. California, Hawaii, and Washington are the states with the highest EV adoption rates. Based on previous research, a list of 12 characteristics that may influence EV adoption was compiled and applied to each state, focusing on …

Impact Of Pollution On Marginalized Communities: Case Study Of Omaha, Nebraska, Miqaela Davis

Department of Environmental Studies: Undergraduate Student Theses

Environmental justice has been a struggle within our country for years. The goal of Environmental justice is for the fair treatment and equal voice for every single individual regardless of race, income, gender, etc. There has been environmental injustice and racism in many cities, but this study focuses on Omaha, Nebraska. Key questions include: What are some specific pollutants that are prevalent in areas with differing racial majorities in Omaha? What are some of the health patterns in these areas and does it relate to environmental racism? How has Omaha reinforced environmental racism through city planning? Using the Climate and …

Educational Influences On Environmental Perception: A Semester Analysis Of The New Ecological Paradigm Scale In Undergraduates, Zoe Zingler

Department of Environmental Studies: Undergraduate Student Theses

This study evaluated the impact of a geography course, GEOG 181: Global Environmental Issues, at the University of Nebraska-Lincoln on students’ endorsement of the New Ecological Paradigm (NEP) using a pre-course and post-course NEP scale survey. Analyzing paired responses (n = 40) through t-tests and z-scores, only four of 15 statements had statistically significant shifts observed for the entire sample. However, a targeted analysis of students initially possessing lower endorsement of the NEP—early deniers—revealed significant paradigm shifts post-course. While women initially showed stronger NEP endorsement, men demonstrated notable changes following the course towards endorsement of the NEP. Academic majors, whether …

Sliding Markov Decision Processes For Dynamic Task Planning On Uncrewed Aerial Vehicles, Trent Wiens

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Mission and flight planning problems for uncrewed aircraft systems (UASs) are typically large and complex in space and computational requirements. With enough time and computing resources, some of these problems may be solvable offline and then executed during flight. In dynamic or uncertain environments, however, the mission may require online adaptation and replanning. In this work, we will discuss methods of creating MDPs for online applications, and a method of using a sliding resolution and receding horizon approach to build and solve Markov Decision Processes (MDPs) in practical planing applications for UASs. In this strategy, called a Sliding Markov Decision …

Development Of A Multi-Use Modular Microfluidic Platform Using 3d Printing, Carson Emeigh

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Microfluidic lab-on-a-chip (LoC) technology has driven numerous innovations due to their ability to perform laboratory-scale experiments on a single chip using microchannels. Although LoC technology has been innovative, it still suffers from limitations related to its fabrication and design flexibility. Typical LoC fabrication, with photolithography, is time consuming, expensive, and inflexible. To overcome the limitations of LoC devices, modular microfluidic platforms have been developed where multiple microfluidic modules, each with a specific function or group of functions, can be combined on a single platform. Modular microfluidics have overcome some of the limitations of LoC devices, but currently, their fabrication is …

Paying To Reduce Disparity: Financially Incentivizing Workforce Diversity And Its Effects On Managers’ Promotion Decisions And Employees’ Effort, Bret S. Sheeley

College of Business: Dissertations, Theses, and Student Research

Disparities in employee representation persist in higher-level organizational positions despite recent attention to workforce diversity and its associated benefits. In response, companies have begun integrating diversity initiatives with varying degrees of specificity (hereafter, “initiative specificity”) into their managers’ compensation packages to increase underrepresented employees’ representation in higher-level organizational positions. This study uses an experiment to examine how offering managers financial incentives to accomplish diversity initiatives (hereafter, “diversity incentives”) and initiative specificity interact to influence managers’ promotion decisions and employees’ effort choices in a promotion setting.

The results suggest that as underrepresented employees’ pre-promotion efforts increase relative to overrepresented employees’ efforts, …

Breakaway Luminaire Pole Research, Jacob Conway

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

This document reports the efforts conducted to determine critical parameters and configurations for Manual for Assessing Safety Hardware 2016 (MASH) Test Level 3 (TL-3) compliant breakaway luminaire poles supported by slip bases, including identifying pole configurations with the potential to meet MASH TL-3 as well as recommending critical configurations for full-scale crash testing. A thorough literature review was conducted which included survey results collected from Midwest Pooled Fund state departments of transportation (DOTs), standard plans from state DOT’s, and past luminaire pole testing.

Numerical LS-DYNA models were developed for luminaire poles with 4-bolt slip base utilized by the Utah Department …

The Kruger Collection Reimagined: A Case Study In 3d Scanning And Interactive Exhibit Design, Annissa Davis

Department of Anthropology: Theses and Student Research

This thesis examines the use of 3D modeling in museum exhibition to create exploratory exhibits that facilitate unique relationships between the visitors and the collection beyond what is provided by the collection’s in person counterparts. Typical use of 3D modeling in museums is currently often representative rather than exploratory. By employing a Digital Humanities lens to approach the development of a digital exhibition utilizing 3D technology and interactive elements created in a video game engine (Unity), this thesis project evaluates these potential new relationships. Using the Eloise Kruger Collection of Miniatures as a case study, the following text details the …

Bidding Strategy For A Wind Power Producer In Us Energy And Reserve Markets, Anne Stratman

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

Wind power is one of the world's fastest-growing renewable energy resources and has expanded quickly within the US electric grid. Currently, wind power producers (WPPs) may sell energy products in US markets but are not allowed to sell reserve products, due to the uncertain and intermittent nature of wind power. However, as wind’s share of the power supply grows, it may eventually be necessary for WPPs to contribute to system-wide reserves. This paper proposes a stochastic optimization model to determine the optimal offer strategy for a WPP that participates in the day-ahead and real-time energy and spinning reserve markets. The …

Vr Circuit Simulation With Advanced Visualization For Enhancing Comprehension In Electrical Engineering, Elliott Wolbach

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

As technology advances, the field of electrical and computer engineering continuously demands innovative tools and methodologies to facilitate effective learning and comprehension of fundamental concepts. Through a comprehensive literature review, it was discovered that there was a gap in the current research on using VR technology to effectively visualize and comprehend non-observable electrical characteristics of electronic circuits. This thesis explores the integration of Virtual Reality (VR) technology and real-time electronic circuit simulation with enhanced visualization of non-observable concepts such as voltage distribution and current flow within these circuits. The primary objective is to develop an immersive educational platform that makes …

An Investigation Of Information Structures In Dna, Joel Mohrmann

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

The information-containing nature of the DNA molecule has been long known and observed. One technique for quantifying the relationships existing within the information contained in DNA sequences is an entity from information theory known as the average mutual information (AMI) profile. This investigation sought to use principally the AMI profile along with a few other metrics to explore the structure of the information contained in DNA sequences.

Treating DNA sequences as an information source, several computational methods were employed to model their information structure. Maximum likelihood and maximum a posteriori estimators were used to predict missing bases in DNA sequences. …

Are Researchers Citing Their Data? A Case Study From The U.S. Geological Survey, Grace C. Donovan, Madison L. Langseth

Copyright, Fair Use, Scholarly Communication, etc.

Data citation promotes accessibility and discoverability of data through measures carried out by researchers, publishers, repositories, and the scientific community. This paper examines how a data citation workflow has been implemented by the United States Geological Survey (USGS) by evaluating publication and data linkages. Two different methods were used to identify data citations: examining publication structural metadata and examining the full text of the publication. A growing number of USGS researchers are complying with publisher data sharing policies aimed to capture data citation information in a standardized way within associated publications. However, inconsistencies in how data citation information is documented …

Kinetics-Based Inference Of Environment-Dependent Microbial Interactions And Their Dynamic Variation, Hyun-Seob Song, Na-Rae Lee, Aimee K. Kessell, Hugh C. Mccullough, Seo-Young Park, Kang Zhou, Dong-Yup Lee

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Microbial communities in nature are dynamically evolving as member species change their interactions subject to environmental variations. Accounting for such context-dependent dynamic variations in interspecies interactions is critical for predictive ecological modeling. In the absence of generalizable theoretical foundations, we lack a fundamental understanding of how microbial interactions are driven by environmental factors, significantly limiting our capability to predict and engineer community dynamics and function. To address this issue, we propose a novel theoretical framework that allows us to represent interspecies interactions as an explicit function of environmental variables (such as substrate concentrations) by combining growth kinetics and a generalized …

Linking Reactive Nitrogen Species Within The Vadose Zone With Surface Irrigation, Kaitlyn Richards

Honors Program: Senior Projects (Public)

This study investigated the relationship between irrigation methods and the mobilization of nitrogen in the vadose zone, focusing on soil properties, water dynamics, and nitrogen species distribution. Data collected from dryland and pivot-irrigated soil cores reveal distinct patterns in water content, bulk density, soil texture, pH, conductivity, and nitrogen concentrations. Results indicated that water content has a major influence in nitrogen availability and microbial activity. Nitrate-N and ammonium-N concentrations varied between dryland and pivot soils, with notable disparities observed. In dryland soils, nitrate-N concentrations varied widely across depth intervals, with notable accumulation in deeper layers, while ammonium-N concentrations exhibited a …

Overexpression Of Msdreb1c Modulates Growth And Improves Forage Quality In Tetraploid Alfalfa (Medicago Sativa L.), Yangyang Zhang, Zhen Wang, Fan Zhang, Xue Wang, Yajing Li, Ruicai Long, Mingna Li, Xianyang Li, Quanzhen Wang, Qingchuan Yang, Junmei Kang

Department of Agronomy and Horticulture: Faculty Publications

DREB has been reported to be involved in plant growth and response to environmental factors. However, the function of DREB in growth and development has not been elucidated in alfalfa (Medicago sativa L.), a perennial tetraploid forage cultivated worldwide. In this study, an ortholog of MtDREB1C was characterized from alfalfa and named MsDREB1C accordingly. MsDREB1C was significantly induced by abiotic stress. The transcription factor MsDREB1C resided in the nucleus and had self-transactivation activity. The MsDREB1C overexpression (OE) alfalfa displayed growth retardation under both long-day and short-day conditions, which was supported by decreased MsGA20ox and upregulated MsGA2ox in the OE …

Injectable And Rapidly Expandable Thrombin-Decorated Cryogels Achieve Rapid Hemostasis And High Survival Rates In A Swine Model Of Lethal Junctional Hemorrhage, Syed Muntazir Andrabi, S.M. Shatil Shahriar, Al-Murtadha Al-Gahmi, Benjamin L. Wilczewski, Mark A. Carlson, Jingwei Xie

Department of Mechanical and Materials Engineering: Faculty Publications

Effective therapies are urgently needed to stabilize patients with marginally compressible junctional hemorrhage long enough to get them to the hospital alive. Herein, we report injectable and rapidly expandable cryogels consisting of polyacrylamide and thrombin (AT cryogels) created by cryo-polymerization for the efficient management of lethal junctional hemorrhage in swine. The produced cryogels have small pore sizes and highly interconnected porous architecture with robust mechanical strength. The cryogels exhibit rapid shape memory properties and prove to be resilient against fatigue. These cryogels also show high water/blood absorption capacity, fast blood clotting effect, and enhanced adhesion of red blood cells and …

Evaluating Consistency Across Multiple Neospectra (Compact Fourier Transform Near-Infrared) Spectrometers For Estimating Common Soil Properties, Sadia M. Mitu, Colleen Smith, Jonathan Sanderman, Richard R. Ferguson, Keith Shepherd, Yufeng Ge

Department of Agronomy and Horticulture: Faculty Publications

Rapid and cost-effective techniques for soil analysis are essential to guide sustainable land management and production agriculture. This study aimed at evaluating the performance and consistency of portable handheld Fourier-transform near-infrared spectrometers and the NeoSpectra scanners in estimating 12 common soil physical and chemical properties including pH; organic carbon (OC); inorganic carbon (IC); total nitrogen (TN); cation exchange capacity (CEC); clay, silt, and sand fractions; and exchangeable potassium (K), phosphorus (P), calcium (Ca), and magnesium (Mg). A diverse set of samples (n = 600) were retrieved from a national-scale soil archive of the Kellogg Soil Survey Laboratory of USDA-NRCS …

Scalable Relational Analysis Via Relational Bound Propagation, Clay Stevens, Hamid Bagheri

School of Computing: Faculty Publications

Bounded formal analysis techniques (such as bounded model checking) are incredibly powerful tools for today’s software engineers. However, such techniques often suffer from scalability challenges when applied to large-scale, real-world systems. It can be very difficult to ensure the bounds are set properly, which can have a profound impact on the performance and scalability of any bounded formal analysis. In this paper, we propose a novel approach—relational bound propagation—which leverages the semantics of the underlying relational logic formula encoded by the specification to automatically tighten the bounds for any relational specification. Our approach applies two sets of semantic rules to …

Data-Driven Evidence-Based Syntactic Sugar Design, David Obrien, Robert Dyer, Tien N. Nguyen, Hridesh Rajan

School of Computing: Faculty Publications

Programming languages are essential tools for developers, and their evolution plays a crucial role in supporting the activities of developers. One instance of programming language evolution is the introduction of syntactic sugars, which are additional syntax elements that provide alternative, more readable code constructs. However, the process of designing and evolving a programming language has traditionally been guided by anecdotal experiences and intuition. Recent advances in tools and methodologies for mining open-source repositories have enabled developers to make datadriven software engineering decisions. In light of this, this paper proposes an approach for motivating data-driven programming evolution by applying frequent subgraph …

Controlling The Broadband Enhanced Light Chirality With L-Shaped Dielectric Metamaterials, Ufuk Kilic, Matthew Hilfiker, Shawn Wimer, Alexander Ruder, Eva Schubert, Mathias Schubert, Christos Argyropoulos

Department of Electrical and Computer Engineering: Faculty Publications

The inherently weak chiroptical responses of natural materials limit their usage for controlling and enhancing chiral light-matter interactions. Recently, several nanostructures with subwavelength scale dimensions were demonstrated, mainly due to the advent of nanofabrication technologies, as a potential alternative to efficiently enhance chirality. However, the intrinsic lossy nature of metals and the inherent narrowband response of dielectric planar thin films or metasurface structures pose severe limitations toward the practical realization of broadband and tailorable chiral systems. Here, we tackle these problems by designing all-dielectric silicon-based L-shaped optical metamaterials based on tilted nanopillars that exhibit broadband and enhanced chiroptical response in …

Five Suggestions Towards User-Centered Data Repositories In The Social Sciences, Elias Herman Kruithof, Christophe Vanroelen, Laura Van Den Borre

Copyright, Fair Use, Scholarly Communication, etc.

Data repositories for the social sciences are facing some discipline-specific challenges. This essay provides an overview of the four key challenges. In addition, five suggestions are made to strengthen domain-specific online data repositories in the social sciences, supported by good practices. Using a user-centered approach, these suggestions aim to further open up the social sciences data landscape. The essay first addresses insights regarding the sharing of quantitative and qualitative data in light of the specific needs and issues regarding these two types of data. Thereafter, we suggest (i) ‘data labs’ for novice data re-users, (ii) advocate for the repository as …

Assessment Of Satellite-Based Water Requirements For A Drip-Irrigated Apple Orchard In Mediterranean Agroclimatic Conditions, Daniel De La Fuente-Saiz, Samuel Ortega-Farias, Marcos Carrasco-Benavides, Samuel Ortega-Salazar, Fei Tian, Sufen Wang, Yi Liu

Department of Civil and Environmental Engineering: Faculty Publications

Accurate assessment of evapotranspiration (ETa) and crop coefficient (Kc) is crucial for optimizing irrigation practices in water-scarce regions. While satellite-based surface energy balance models offer a promising solution, their application to sparse canopies like apple orchards requires specific validation. This study investigated the spatial and temporal dynamics of ETa and Kc in a drip-irrigated ‘Pink Lady’ apple orchard under Mediterranean conditions over three growing seasons (2012/13, 2013/14, 2014/15). The METRIC model, incorporating calibrated sub-models for leaf area index (LAI), surface roughness (Z_om), and soil heat flux (G), was employed to estimate ETa and Kc. These estimates were validated …

Community And Regional Economic Analysis: Unveiling Economic Dynamics With The Location Quotient Method And Beyond, Daniela M. Mattos

Cornhusker Economics

In addition to the Location Quotient analysis, several other economic development analytical tools can contribute valuable insights to investment decisions, such as population-employment ratios and shift-share analysis. The use concomitant of these tools boosts the information provided by the Location Quotient analysis, offering a more holistic perspective. Recognizing that each analytical tool provides only a partial view, it is essential not to rely solely on one method when making investment decisions. Comprehensive decision-making necessitates leveraging multiple tools to gain a more nuanced and accurate understanding of local economies.

Globe-Lfmc 2.0, An Enhanced And Updated Dataset For Live Fuel Moisture Content Research, Marta Yebra, Gianluca Scortechini, Karine Adeline, Nursema Aktepe, Turkia Almoustafa, Avi Bar-Massada, María Eugenia Beget, Matthias Boer, Ross Bradstock, Tegan Brown, Francesc Xavier Castro, Rui Chen, Emilio Chuvieco, Mark Danson, Cihan Ünal Değirmenci, Ruth Delgado-Dávila, Philip Dennison, Carlos Di Bella, Oriol Domenech, Jean-Baptiste Féret, Greg Forsyth, Eva Gabriel, Zisis Gagkas, Fatma Gharbi, Elena Granda, Anne Griebel, Binbin He, Matt Jolly, Ivan Kotzur, Tineke Kraaij, Agnes Kristina, Pınar Kütküt, Jean-Marc Limousin, M. Pilar Martín, Antonio T. Monteiro, Marco Morais, Bruno Moreira, Florent Mouillot, Samukelisiwe Msweli, Rachael H. Nolan, Grazia Pellizzaro, Yi Qi, Xingwen Quan, Victor Esco De Dios, Dar Roberts, Çağatay Tavşanoğlu, Andy F. S. Taylor, Jackson Taylor, İrem Tüfekcioğlu, Andrea Ventura, Nicolas Younes Cardenas

School of Natural Resources: Faculty Publications

Globe-LFMC 2.0, an updated version of Globe-LFMC, is a comprehensive dataset of over 280,000 Live Fuel Moisture Content (LFMC) measurements. These measurements were gathered through field campaigns conducted in 15 countries spanning 47 years. In contrast to its prior version, Globe-LFMC 2.0 incorporates over 120,000 additional data entries, introduces more than 800 new sampling sites, and comprises LFMC values obtained from samples collected until the calendar year 2023. Each entry within the dataset provides essential information, including date, geographical coordinates, plant species, functional type, and, where available, topographical details. Moreover, the dataset encompasses insights into the sampling and weighing procedures, …