Physical Sciences and Mathematics Commons^™

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 …

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 …

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 …

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 …

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 …

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 …

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 …

Approximation Via Degree Reduction Of Nonlinearities With Applications To Turbulent Flows, Flame Fronts, And Magnetohydrodynamics, Matthew Enlow

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

We perform an analytical and computational investigation on the effectiveness of a locally bounded truncation function, which we call a calming function, when applied to the nonlinear terms of several dissipative partial differential equations. In particular, the 3D Navier-Stokes equations of incompressible fluid flow, the 2D Kuramoto-Sivashinsky equations of laminar flame fronts, and the 2D MHD-Boussinesq equations of magnetohydrodynamics. Each of these equations have open questions about the global existence and uniqueness of their solutions. These calming functions effectively reduce the algebraic degree of select nonlinear terms, thus one can verify global wellposedness for these "calmed systems." More specifically, in …

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 …

The Effects Of Partisanship On Legislative Support For Environmental Policies In The United States, Rachel Summers

Department of Environmental Studies: Undergraduate Student Theses

This study investigates the relationship between political partisanship and support for environmental policies at the state level in the United States from the years 2017-2022. To do this, the study focused on two policy areas, water and land, for the average proposed, enacted, and failed bills for all 50 states in the timeframe, with the states categorized as Democratic, swing, or Republican based on the 2016 and 2020 elections. While the study did find that Democratic states were more likely to introduce environmental bills than Republican states, the study also found that there was no statistical difference in the enactment …

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 …

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 …

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 …

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 …

Stress Phenotyping Analysis Leveraging Autofluorescence Image Sequences With Machine Learning, Sruti Das Choudhury, Carmela Rosaria Guadagno, Srinidhi Bashyam, Anastasios Mazis, Brent E. Ewers, Ashok Samal, Tala Awada

School of Natural Resources: Faculty Publications

Background: Autofluorescence-based imaging has the potential to nondestructively characterize the biochemical and physiological properties of plants regulated by genotypes using optical properties of the tissue. A comparative study of stress tolerant and stress susceptible genotypes of Brassica rapa with respect to newly introduced stress-based phenotypes using machine learning techniques will contribute to the significant advancement of autofluorescence-based plant phenotyping research.

Methods: Autofluorescence spectral images have been used to design a stress detection classifier with two classes, stressed and non-stressed, using machine learning algorithms. The benchmark dataset consisted of time-series image sequences from three Brassica rapa genotypes (CC …

Predicting The Potential Distribution Of Pseudococcus Longispinus (Targioni-Tozzetti) (Hemiptera: Pseudococcidae) In South Korea Using A Climex Model, Su Bin Kim, Soo-Jung Suh

Insecta Mundi

Pseudococcus longispinus (Targioni-Tozzetti) (Hemiptera: Pseudococcidae) is a widely-distributed pest that feeds on many economically important hosts, particularly tropical fruits and ornamentals. The potential distribution of this mealybug pest in South Korea remains a primary concern because of its high incidence of interceptions screened during inspection. Hence, this species prompted a modelling effort to assess its potential risk of introduction. Potential risk maps were developed for this pest with a CLIMEX model based on occurrence records under environmental data. The potential distribution of these pests in South Korea in the 2020s, 2050s and 2090s was projected based on the RCP 8.5 …

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, …

Phys 211h

Department of Physics and Astronomy: Syllabi

No abstract provided.

Phys 918

Department of Physics and Astronomy: Syllabi

No abstract provided.

Phys 926

Department of Physics and Astronomy: Syllabi

No abstract provided.

Phys 401/801

Department of Physics and Astronomy: Syllabi

No abstract provided.