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5-Year Strategic Direction, 2024–2028: Institute Of Agriculture And Natural Resources, University Of Nebraska–Lincoln, Institute Of Agriculture And Natural Resources University Of Nebraska-Lincoln

Institute of Agriculture and Natural Resources: Institute Publications

IANR: Integrating Learning, Discovery, and Engagement for an Even Better Nebraska

Includes an introduction, description of the components of the Institute of Agriculture and Natural Resources at the University of Nebraska–Lincoln, the IANR pillars, stratgeic aims for 2024–2028, and a section on implementation.

Public Horticulture: Process And Design Of The Lincoln Botanical Garden, Brad Kindler

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Beginning in 2012, the local non-profit, The Lincoln Botanical Garden, began organizing the conceptual design and creation of a glass conservatory within a botanical garden in Lincoln, Nebraska. These proposed urban enhancements seek to fill a gap in garden amenities in the city by providing year-round access to public horticulture programming and education.

This project, Public Horticulture: Process and Design of the Lincoln Botanical Garden, documents these efforts and makes design recommendations for a themed Glacial Erratic Garden that could be constructed within the botanical garden.

Advisors: Ellen Paparozzi and Sam Wortman

Understanding The Zonal Variability In Cmip6 Projections Of Sahelian Precipitation, Emmanuel Ogwuche Audu

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

The uncertainty in model projections of future precipitation across the Sahel has persisted across many generations of Earth System Models (ESMs), with some models predicting drying and others moistening across this region. These discrepancies in future projections pose a challenge for stakeholders and decision makers. Many projections of Sahel precipitation found in the ESMs participating in the sixth phase of Coupled Model Intercomparison Project (CMIP6) show a zonal dipole in precipitation trend, with moistening across the Central and Eastern Sahel and drying projected for the Western Sahel. Previous studies have connected precipitation variability across the Sahel to changes in various …

Polarimetric Radar Signatures In Significant Severe Left-Moving Supercells, Raychel Nelson

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Left-moving (LM) supercells, though rarer than right-moving (RM) supercells, may produce significant severe weather. However, there are very few existing studies on LM supercells, particularly polarimetric radar analyses. The upgrade of the nationwide Weather Surveillance Radar-1988 Doppler (WSR-88D) network to polarimetric capability and subsequent studies vastly improved understanding of RM supercells, but similar efforts have largely not been made for LM supercells. This study employs an automated polarimetric radar signature detection algorithm to examine a dataset of significant severe (hail ≥ 2.00”, wind ≥ 65 kts) LM supercells to quantify their polarimetric signatures. Comparisons are made with RM supercells to …

A Dual-Polarimetric Analysis Of A Large Sample Of Left-Moving Supercells, Ben Schweigert

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Supercells have been researched extensively since they were first described over 50 years ago. They are prolific severe weather producers, responsible for the most severe hail, severe wind gusts, and tornadoes. These rotating thunderstorms require attention from forecasters to protect life and property from their threats, most effectively done with Doppler radars. While extensive amounts of radar-based investigations have been completed, they focused almost exclusively on right-moving (RM) supercells, resulting in a knowledge gap surrounding their counter-rotating (left-moving, LM) partners. This study works to fill the void by developing a dataset of LM supercells and analyzing the dual-polarimetric features observed …

Spatial Hearing In Simulated Reverberant Classroom Environments, Gabriel Seth Evan Weeldreyer

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

Spatial hearing provides access to auditory spatial cues that promote speech perception in noisy listening situations. However, reverberation degrades auditory spatial cues and limits listeners’ ability to utilize these cues for segregating target speech from competing babble. Hence, spatial unmasking—an intelligibility benefit from a spatial separation between a target and masker—is reduced in reverberant environments as compared to free field. This work tests the hypothesis that interaural decorrelation, the result of increasing reverberation, will broaden the perceived auditory source width with a cascading effect of reduced auditory spatial acuity and subsequently poorer spatial unmasking. To understand the perceptual consequences of …

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 …

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 …

First-Principles Studies Of Spin Transport And Spin-Orbit Torques, Giovanni Gabriel Báez Flores

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

This dissertation presents first-principles studies focusing on the effects of interfacial spin relaxation in metallic interfaces, interfacial intermixing on spin-orbit torques, and the effects of alloying on the transport properties of Fe|MgO|Fe magnetic tunnel junctions. Spin transport and spin-orbit torques are at the heart of phenomena in magnetic memory devices, such as tunnel magnetoresistance and magnetization switching. This work explores spin transport, spin-orbit coupling, spin-orbit torques, and tunneling magnetoresistance in a variety of materials and interfaces.

First discussed is the role of spin-orbit coupling at metallic interfaces by establishing a generalized magnetoelectronic circuit theory for normal metal (NM) interfaces, (NM|NM), …

Vibratory Noise Impacts The Sensory Ecology Of A Funnel-Weaving Spider, Brandi June Pessman

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

Animals experience their world through diverse sensory systems, leveraging information from prey, predators, and potential mates to inform behavioral decisions. Environmental noise disrupts information via spectral or amplitude masking, degradation, or distortion, potentially leading to costly errors in responses. Critically, urbanization has accelerated the proliferation of novel noise sources, triggering significant shifts in communication, foraging, and predator-prey dynamics among urban wildlife. While vertebrate studies have illuminated urban animals’ flexibility to anthropogenic acoustic noise, a comprehensive understanding requires broader investigations across diverse animal taxa and sensory modalities. To address these gaps, my dissertation explored the impacts of anthropogenic substrate-borne (vibratory) noise …

Genome-Scale Metabolic Modeling Of Chitin-Degrading Microbial Systems, Aimee Kristin Kessell

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

As a major component of fungal cell walls and exoskeletons of invertebrates, chitin is widespread in soils, constituting the second most abundant biopolymer in nature. Composed of N-acetyl-D-glucosamine chains, it serves as a vital source of nutrients, including both carbon and nitrogen, for the growth of microorganisms. A solid understanding of the microbial degradation of chitin is critical for predicting their impacts on biogeochemical cycling in soil ecosystems. Organisms that degrade biopolymers (degraders) produce energetically expensive extracellular enzymes to break down complex organic carbons into simpler labile forms that are sharable with other species, including those that do not contribute …

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 …

Effect Of Biomass Water Dynamics In Cosmic-Ray Neutron Sensor Observations: A Long-Term Analysis Of Maize–Soybean Rotation In Nebraska, Tanessa Morris

School of Natural Resources: Dissertations, Theses, and Student Research

The precise measurement of soil water content (SWC) is crucial for effective water resource management. This study utilizes the Cosmic Ray Neutron Sensor (CRNS) for area-averaged SWC measurements, emphasizing the need to consider all hydrogen sources, including the time-variable ones like plant biomass and water content. Chapter 1 presents a background on soil moisture estimation, CRNS technology, and an overview of the study. It discusses various soil moisture measurement techniques, highlights the gap in knowledge addressed by CRNS technology, explains CRNS functionality and advancements, and outlines the study's motivations and methods.

Chapter 2 reports a study conducted near Mead, Nebraska, …

A Compilation, Analysis, And Categorization Of 403 Atmospheric And Climate Science Misconceptions, Haeli Leighty

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

The National Association of Geoscience Teachers (NAGT) has listed the inaccessibility of research related to misconceptions in atmospheric and climate science as a Geoscience Education Research Grand Challenge (Cervato et al. 2018). This project was a direct response to this call for research and consisted of three distinct steps: 1) data gathering, which included reviewing the literature for relevant misconception data, 2) a qualitative analysis, which included compiling, organizing, and categorizing the data collected, and 3) a quantitative analysis, which included determining the prevalence of each misconception across topic categories, demographic categories, and over time. A total of 403 misconceptions …

Curriculum For All: An Introduction To Calculus, Maggie Scott

Honors Program: Senior Projects (Public)

Math is one of the only subjects that builds upon itself throughout a student’s educational career. Progressing through each course, students are taught concepts that build upon each other year after year. The content is engaged with itself, yet, it’s historically taught in a non-engaging way. Through my research of math education and my experience as a math teacher, it’s apparent that the most successful math classrooms are the ones that elicit student thinking and allow for self-discovery. (Azad)

Most people have very polarized views of math. Some love it, and some hate it, but almost all students can remember …

An Interdisciplinary Lesson Plan Of Social Studies And English Language Arts For Third Graders, Sidney L. Yant

Honors Program: Senior Projects (Public)

My name is Sidney Yant and I am a current senior honors student at the University of Nebraska-Lincoln. I am majoring in Elementary Education. For my honors senior project, I have created a four-week-long unit lesson plan that focuses on English Language Arts and Social Studies. This unit starts off with two weeks of separate lesson plans for English Language Arts and Social Studies and then the last two weeks the lessons are completely integrated together into one plan.

Evaluating Oer Resources As An Inclusive Teaching Practice, Hannah Ray

Honors Program: Senior Projects (Public)

Open Educational Resources (OER) have become a popular alternative to traditional textbooks for university students throughout the U.S. due to their affordability and positive educational outcomes. To better determine the outcomes of OER usage, this study evaluates the implementation of OER at an individual course level and across courses at the University of Nebraska-Lincoln (UNL). Student success was measured by the DFW rates, which refers to the number of students who received a grade letter of D, failed, or withdrew from the course, before and after the implementation of OER resources in various courses. At the individual course level, students’ …

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. …

Mathematical And Computational Analysis Of Certain Regularizations For The 3d Navier-Stokes Equations And Nonlocal Peridynamic Conservation Laws, Isabel Safarik

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

Voigt regularization is a technique used to model turbulent flows, offering advantages such as sharing steady states with the Navier-Stokes equations and requiring no modification of boundary conditions. We explore a modification to the Voigt regularization technique by introducing fractional dissipation into the system, specifically incorporating a fractional power, r. In this work, the proofs are in the context of periodic boundary conditions. The resulting fractional Navier-Stokes-Voigt (fNSV) and fractional Euler-Voigt (fEV) equations are studied for global well-posedness in three dimensions. It is shown that global well-posedness holds in the 3D case for fEV when the fractional power r …

Ecological Dynamics Of Cenozoic North American Mammals, Alexandria Brandis Shupinski

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

Understanding how community structure is affected by various ecological, climatic, and environmental changes is a long-standing goal in ecology. However, disentangling human impacts from these other variables is difficult when using short modern timescales and anthropogenically altered communities. The fossil record provides a means to investigate community structure dynamics across critical intervals, excluding humans as a variable. Here, in three studies, I assess changes in North American mammal paleocommunity structure across the last 66 million years (Ma) at multiple temporal and spatial scales. In Chapter 1, I identify changes in mammal functional diversity (FD) locally and continentally, using three independent …

Lockheed Martin Strategic Audit, Trevor Deboer, Gunnar Lombard, Sam Nelson, Tj Taylor, Paul Wynegar

Honors Program: Senior Projects (Public)

Abstract

This case study explores Lockheed Martin, a global leader in defense contracting. Our team performed a strategic audit using the theories of strategic management. Our research was pulled from various sources, including Lockheed Martin’s website, SEC filings, related news articles, and relevant industry analysis. The goals of this case study revolved around collecting data and performing analysis to evaluate Lockheed Martin’s potential for competitive advantage in the airplane and parts manufacturing industry.

Some of the various analyses performed on Lockheed Martin include firm analysis, industry analysis, internal analysis, external analysis, competitive dynamics, business-level strategy, corporate-level strategy, and exploring their …

Drag Reduction In Channel Flow Configurations For Laminar And Turbulent Flow Past Superhydrophobic Surfaces, Henry Louis Ems

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

In this work, we present friction drag reduction in minichannel laminar flow past superhydrophobic metallic surfaces. Femtosecond laser surface processing (FLSP), a one-step scalable method, was used to create permanent microscale and nanoscale structures on 316 stainless steel plates. The resulting superhydrophilic plates were covered by tall (215 μm) or short (27 μm) structures. The FLSP plates were then transitioned to superhydrophobic by evaporative deposition of a fluorinated silane, a low surface energy coating. Using purified water, the friction factor was obtained by measuring pressure drop along a minichannel with a rectangular cross section for flow rates corresponding …

Aggregate Games: Computations And Applications, Jared Soundy

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

Existing computational game theory studies consider compact representations of games that capture agent interaction in real-world environments and examine computation aspects of computing equilibrium concepts to analyze or predict agent behavior.

One of the most well-studied representations that capture many commonly studied real-world environments is aggregate games. Aggregate games, first systematically studied by Nobel laureate Reinhard Selten, have various applications in modeling the decision-making interdependence of agents, where each agent’s utility function depends on their own actions and the aggregations or summarizations of the actions of all agents. These applications include Cournot oligopoly competition, public good contribution, and voting, where …

Strong First Order Electroweak Phase Transitions In The Standard Model With A Real Scalar Singlet Extension, Anthony James Hooper

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

The large matter-antimatter asymmetry of the universe and whether the electroweak sector has always been broken are currently unanswered by the standard model (SM). One solution that addresses both these concerns is to impose a strong first order electroweak phase transition (SFOEWPT) and ensure electroweak baryogenesis occurs. Models that undergo a SFOEWPT in the early universe create bubbles of the true vacuum that expand until the universe reaches the vacuum expectation value measured today. If the phase transition is strong enough, then these bubbles may generate a detectable stochastic gravitational wave (GW).

However, the SM by itself can only perform …

Concepts In Animal Parasitology: Master Bibliography, Sue Ann Gardner

Concepts in Animal Parasitology

Master bibliography for the open educational resource/open access textbook Concepts in Animal Parasitology, Scott L. Gardner and Sue Ann Gardner, editors, published by Zea Books, Lincoln, Nebraska, United States, 2024. This includes the references from literature cited and suggested supplemental reading.

Consequences Of The Megafauna Extinction: Changes In Food Web Networks On The Edwards Plateau Across The Pleistocene–Holocene Transition, Quentin A. Smith Jr.

School of Biological Sciences: Dissertations, Theses, and Student Research

We are experiencing biodiversity loss due to climate change and human impacts, which is not only harmful to the environment but can also alter the composition of communities and interactions among species. The late Pleistocene experienced a loss of large-bodied mammals which resulted in significant changes in community structure due to changes in body size, diet, and species associations. The impact of these changes on species interactions and community structure across the Pleistocene-Holocene transition remains poorly understood. Using a robust data set of species composition, stable isotopes, body size, and climate variables, we constructed and compared ecological networks of mammal …

Adding Parasite Resistance To A Hair Sheep Breeding Objective, Robert M. Forbes

Department of Animal Science: Dissertations, Theses, and Student Research

The United States Hair Sheep Index was designed to increase total weight of lamb weaned per ewe lambing (TW) using estimated breeding values (EBV) for direct (DWWT) and maternal (MWWT) weaning weight, and number of lambs born (NLB) and weaned (NLW), as selection criteria. Producers are interested in adding post-weaning fecal egg count EBV (PFEC), an indicator of parasite resistance, to the index to achieve genetic change in both TW and PFEC.

First, the effects of adding PFEC alongside TW to the breeding objective of indexes that used either phenotypes or EBV as selection criteria were studied. Since MWWT …

Nonlocal Frameworks For Differential Equations--Analysis And Numerical Investigations, Layla Montemayor

Honors Program: Senior Projects (Public)

Systems of differential equations have been employed successfully in nearly every scientific field, including natural phenomena, finance, A.I. and machine learning. In a classical set up, a differentiable equation will be associated with a number of initial conditions that will help determine a unique solution to the system. The setting of classical differential equations requires assumptions on the regularity or smoothness of the input functions. Thus, we cannot produce with classical differential equations solutions which are irregular or even have discontinuities.

To overcome some of these challenges brought up by investigations of irregular or singular behavior, different formulations of nonlocal …

Detection Of Deficiencies And Data Analysis Of Bridge Members With Deep Convolutional Neural Networks, Bennett Jackson

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

Concrete cracks and structural steel corrosion are two of the most common defects in bridges. Quantifying and classifying these defects provide bridge inspectors and engineers with valuable data for assessing deterioration levels. However, the bridge inspection process is typically a subjective, time intensive, and tedious task, as defects can be overlooked or in locations not easily accessible. Previous studies have investigated deep learning-based inspection methods, implementing popular models such as Mask R-CNN and U-Net. The architectures of these models offer certain advantages depending on the required task. This thesis aims to evaluate and compare Mask R-CNN and U-Net regarding their …