Physical Sciences and Mathematics Commons^™

Winter-Time Cover Crop Identification: A Remote Sensing-Based Methodological Framework For New And Rapid Data Generation, Zobaer Ahmed, Lawton L. Nalley, Kristofor R. Brye University Of Arkansas, V. Steven Green, Michael P. Popp, Aaron Michael Shew, Lawson Connor

Environmental Dynamics Faculty Publications and Presentations

Accurately identifying and systematically mapping winter-time cover crops and their phenological characteristics offer significant benefits to agricultural producers and policymakers, as cover crops are one of several potential solutions to climate change mitigation. We present a methodological framework for identifying and mapping the presence of winter-time cover crops at the field level and aggregated to county scales from 2013 to 2019 by using the Google Earth Engine (GEE), a random forest classifier with time series data from Landsat 8, and yearly cover crop training data from the United States Department of Agriculture (USDA)-Natural Resources Conservation Service (NRCS). The methodology was …

Detection Of Dsrab Operon Expression In Desulfotalea Psychrophila Cells Subjected To Simulated Martian Conditions Of Temperature And Regolith's Sulphate Minerals Composition, Sergio Mosquera, Mack Ivey, Vincent F. Chevrier

Biological Sciences Faculty Publications and Presentations

Discoveries of transient liquid water in the Martian polar caps and the presence of liquid lakes and subsurface oceans in icy satellites have increased the interest of scientists in the capabilities of terrestrial extremophiles to grow and remain metabolically active in these extreme environments. The principal goal of this research is to understand the metabolic capacity of the anaerobic psychrophile, Desulfotalea psychrophila, cultured at subfreezing temperatures in media containing various concentrations of sulphate minerals. In this regard, our experiments focused on the detection of D. psychrophila survival and active metabolism, employing a biochamber that can recreate Martian temperatures. Using …

Nanoparticles And The Environment: Biopolymer Grafted Cellulose And Screen-Printed Carbon Nanotube Composites, Dominique Henry Porcincula

Master's Theses

A host of environmental issues will define the state of the environment in the 21^st century, with plastic pollution and water shortages among them. While solutions to these problems require large-scale, multipronged solutions, one way we can address them is through material innovation and the use of nanoparticles.

In the first project, we address the issue of plastic pollution by creating nanocomposites of biodegradable polymers (PLA and PCL) with cellulose nanofibrils. Here, PLA and PCL are grafted from the surface of cellulose nanofibrils via ring-opening polymerization of cyclic ester monomers. Polymer-grafted cellulose (PGC) is characterized with structural analysis, solubility …

Aurora Borealis — Not Bore-Alis! The Northern Lights’ Ancient Legends And Scientific Wonders, Anadi Purewal-Legha

The Synapse: Intercollegiate science magazine

No abstract provided.

Save The Wasps: Conservation Struggles In Protecting An Animal With A Bad Reputation, Megan Tiffany

The Synapse: Intercollegiate science magazine

No abstract provided.

The Neural Manifold: Unfolding The Matrix Of Our Brain, James Lee

The Synapse: Intercollegiate science magazine

No abstract provided.

Using Remote Sensing To Determine Riparian Resilience In Beaver Dammed Versus Un-Dammed Corridors Following Whiplash Weather, Sophie Charlotte Valérie Aubry

Master of Science in Environmental Sciences and Management Projects

Beaver complexes slow and store water allowing for riparian growth which in turn fosters biodiversity, retains carbon, and enhances resistance to fires and drought. Given the benefits associated with beaver complexes and the potential they have for climate mitigation, California hopes to reintroduce beavers and restore their habitat throughout the state. However, the impact of high peak flow events on beaver complexes and their adjacent riparian corridors is less understood and requires more documentation at various spatial scales. To better understand the potential beavers may have as climate change mitigators it is important to understand beaver complex resiliency following a …

Enhanced Privacy-Enabled Face Recognition Using Κ-Identity Optimization, Ryan Karl

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

Facial recognition is becoming more and more prevalent in the daily lives of the common person. Law enforcement utilizes facial recognition to find and track suspects. The newest smartphones have the ability to unlock using the user's face. Some door locks utilize facial recognition to allow correct users to enter restricted spaces. The list of applications that use facial recognition will only increase as hardware becomes more cost-effective and more computationally powerful. As this technology becomes more prevalent in our lives, it is important to understand and protect the data provided to these companies. Any data transmitted should be encrypted …

Co2 Storage Capacity And Injectivity Of Stacked Carbonates Of The Pennsylvanian And Permian In Western Nebraska, Lateef Lawal

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

Geological carbon storage (GCS) is a critical aspect of carbon capture and storage (CCS) in which captured CO₂ from power plants and industrial processes is injected and stored securely underground. Potential subsurface rock formations include saline aquifers, depleted oil and gas reservoirs, unmineable coal seams and volcanic rocks. GCS technology has been proven in the United States and many other parts of the world as a net-zero carbon emission strategy to mitigate the current climate crisis of our planet. Unlike other states such as Wyoming, GCS projects are still in the early phases in Nebraska. The goal of this …

The Discovery Of Diverse Picophytoplankton Populations In The Columbia And Willamette Rivers Using Flow Cytometry, Kylee M. Lamberson

Chemistry Undergraduate Departmental Honors Theses

As important primary producers, picophytoplankton determine the flow of carbon and energy in aquatic ecosystems. Picocyanobacteria are one picophytoplankton group known to be dominant in oceans and lakes, but they are still poorly understood in river systems. This project examined picophytoplankton communities in two distinct river systems: the Columbia and Willamette Rivers in Portland, Oregon. I aimed to characterize and quantify the picophytoplankton populations in the context of the environmental conditions of the two rivers. I used flow cytometry to detect cells based on their relative size and pigment fluorescence. I sampled nearly weekly for ten months to capture population …

Bayesian Strategies For Propensity Score Estimation In Causal Inference., Uthpala I. Wanigasekara

Electronic Theses and Dissertations

Causal inference is a method used in various fields to draw causal conclusions based on data. It involves using assumptions, study designs, and estimation strategies to minimize the impact of confounding variables. Propensity scores are used to estimate outcome effects, through matching methods, stratification, weighting methods, and the Covariate Balancing Propensity Score method. However, they can be sensitive to estimation techniques and can lead to unstable findings. Researchers have proposed integrating weighing with regression adjustment in parametric models to improve causal inference validity. The first project focuses on Bayesian joint and two-stage methods for propensity score analysis. Propensity score modeling …

Homln-Sd: Substructure Discovery In Homogeneous Multilayer Networks, Arshdeep Singh

Computer Science and Engineering Theses

Substructure discovery is a process in data analysis and data mining that involves identifying and extracting meaningful patterns, structures, or components within a larger dataset. These substructures can be of various types, such as frequent patterns, motifs, or any other relevant features within the data. The growth of the internet and the proliferation of mobile devices have led to the generation of enormous amounts of data. Companies like Facebook and Twitter can generate large datasets from user interactions on their websites, such as connections between users and user generated content. Moreover, advances in processing power and storage capacity have made …

Design Of Single Precision Floating Point Unit (32-Bit Numbers) According To Ieee 754 Standard Using Verilog, And Creation Of An Education Model For Advanced Digital Logic And Design Courses, Kartikey Sharan

Computer Science and Engineering Theses

In today’s day and age of arithmetic, Floating Point Arithmetic is by far the most industry sanctioned way of approximating real number arithmetic for making numerical calculations on all computers used by industries on an everyday basis. In the year 1985, IEEE 754 standard was established that defined a single universal standard for all different arithmetic formats [1]. Before this, for a long period each computer had a different arithmetic format and size for bases, significand, and exponents. This format allowed industries all around the world to compute floating point arithmetic in a universal way and facilitated open communication between …

Easemarks: Using Secondary Sketch Marks To Author And Communicate Motion Interpolation, Hadrien Nguyen

Computer Science and Engineering Theses

Motion interpolation is a process where an animator transforms jerky frame transitions into rich motions that communicate anticipation, urgency, hysteresis, and even calmness. Animators leverage mathematical functions known as easing curves to modify the rate at which in-betweens are added to keyframes. While effective, easing curves are tedious to tune since they fundamentally lack the ability to encode spatial information. Inspired by timing charts and other standards from traditional cel animation, we introduce a motion animation technique where secondary marks, which we term EaseMark (e.g., hatches, loops), are used to denote motion interpolation decisions. We synthesize an EaseMark Sketching Language …

Constructing Large Open-Source Corpora And Leveraging Language Models For Simulink Toolchain Testing And Analysis, Sohil Lal Shrestha

Computer Science and Engineering Dissertations

In several safety-critical industries such as automotive, aerospace, healthcare, and industrial automation, MATLAB/Simulink has emerged as the de-facto standard tool for system modeling and analysis, model compilation into executable code, and code deployment onto embedded hardware. Within the context of cyber-physical system (CPS) development, it is imperative to both rigorously test the development tools, such as MathWorks’ Simulink, and understand modeling practices and model evolution. The existing body of work faces limitations primarily stemming from two factors: (1) contemporary testing methodologies often prove inefficient in identifying critical toolchain bugs due to a paucity of explicit toolchain specifications and (2) there …

Hemln-Sd: Substructure Discovery In Heterogeneous Multilayer Networks, Kiran Bolaj

Computer Science and Engineering Theses

Graph mining analyzes the real-world graphs for finding core substructures in chemical compounds (e.g., Benzene), identify the structure that occurs frequently in a given graph or forest. These identified structures are important as they reveal an inherent feature or property in the given graph or forest. Substructures represent interesting and repeating patterns found within an application, offering insights into hidden regularities. Therefore, the process of finding these interesting and frequent patterns in an unsupervised manner is known as substructure discovery. SUBDUE was the first main-memory algorithm developed for substructure discovery. Since then, for scalability, the algorithm has been extended to …

Feasibility Study Of Off-The-Shelf Components On A Split-Cycle Motor And Esc Testbed, Hayden C. Lotspeich

Computer Science and Engineering Theses

This project aims to create a testbed for split-cycle flapping wing systems that allows for testing of different motors and ESC protocols to find a suitable set for a flapping wing system. In order for a flapping-wing drone to be able to maneuver, it has to be able to flap its wings at different speeds when flapping forward and flapping backwards. The arching back-and-forth motion is what the output wing would be connected to, so this system is used to calculate the maximum split-cycle time ratio that can be achieved when set up with different motors and ESC protocols.

Enhancing The Classification Of Autism Spectrum Disorder From Rs-Fmri Functional Connectivity Data Using Temporal Information, Mihir Yashwant Ingole

Computer Science and Engineering Theses

Autism Spectrum Disorder (ASD) affects the patient’s cognitive development which leads to difficulties in social functioning, daily tasks, and independent living. This necessitates intervention at an early age to take preventive measures and provide vital care. Manual diagnosis methods like Autism Diagnostic Observation Schedule (ADOS) assessment adopts symptom-based criteria which typically manifest at a later age. To automate this process, correlations computed from BOLD (Blood Oxygen-level dependent) signals obtained through resting state functional magnetic resonance imaging (rs-fMRI) data of patients across sparse brain regions has been used recently as a measure of functional connectivity. The goal of this study is …

Electrodeposition Studies Of Gold Nanoparticles And Alginate Hydrogel Films., Harikrishnan Nambiathan Nambiar

Electronic Theses and Dissertations

This dissertation investigates the electrochemical deposition (ECD) and electrophoretic deposition (EPD) processes involving citrate (cit)-stabilized Au nanoparticles (NPs) and calcium alginate (Ca-Alg-Au NP) hydrogel films. The first part of the dissertation investigates the influence of NP size, surface area (SA) coverage, and ligand stabilizers on the electrochemical growth of Au on Au NPs, aiming to enhance our understanding of the growth process during the nucleation and growth of metal NPs. The growth kinetics depend on Au NP size (4 nm > 15 nm > 50 nm) for a constant SA coverage, as determined by the overpotentials for ECD. The growth rate increases …

Effects Of A Protection Zone In A Reaction-Diffusion Model With Strong Allee Effect., Isaac Johnson

Electronic Theses and Dissertations

A protection zone model represents a patchy environment with positive growth over the protection zone and strong Allee effect growth outside the protection zone. Generally, these models are considered through the corresponding eigenvalue problem, but that has certain limitations. In this thesis, a general protection zone model is considered. This model makes no assumption on the direction of the traveling wave solution over the Strong Allee effect patch. We use phase portrait analysis of this protection zone model to draw conclusions about the existence of equilibrium solutions. We establish the existence of three types of equilibrium solutions and the necessary …

Scalable Solution Processing Of Niox Nanoparticles., Peter James Armstrong

Electronic Theses and Dissertations

Perovskite solar cells (PSCs) are a promising alternative to silicon-based photovoltaics. However, PSCs face several challenges due to shortcomings in their stability, module efficiency, and scaled production. Although PSCs is still a young field of research, significant attention has been given to demonstrating power conversion efficiencies that are on par with traditional silicon. With that target reached, converting the laboratory demonstration into practical materials to increase access and abundance of solar energy are among the next large targets for the field. This comes with material challenges for perovskite and their companion charge transport layers (CTLs). Among the charge transport materials …

Causal Inference For The Effect Of Continuous Treatment On Time-To-Event Outcomes And Mediation Analysis On Health Disparities In Observational Studies., Triparna Poddar

Electronic Theses and Dissertations

The dissertation comprises two projects related to causal inference based on observational data. In healthcare research, where abundant observational data such as claims data and electronic records are available, researchers often aim to study the treatment effect and the pathway of that effect. However, estimating treatment effects in observational data presents challenges due to confounding factors. The first project focuses on estimating continuous treatment effects for survival outcomes, while the second concentrates on mediation analysis, allowing the exploration of the pathway of the causal effect. Both projects involve addressing confounding variables. In the first project, I investigate estimation of the …

Computational Investigations Of Bond Breaking Processes Using Dft And Td-Dft Approaches., Saurav Parmar

Electronic Theses and Dissertations

The efficient application of DFT and TD-DFT has been harnessed to study bond-breaking processes in some molecules which play a prominent role in enzymatic reactions. The first application includes Radical S-adenosyl methionine (SAM) enzymes which are fundamentally important sources of organic radicals to initiate diverse radical reactions. Recently a bio-organometallic intermediate (Ω) that contains an Fe‒C bond has been characterized and shown to be a common feature of radical SAM enzymes. The strength of Fe‒C bond in Ω has been computed using broken-symmetry density functional theory (BS‒DFT). Additionally, Fe‒C bond dissociation energy (BDE) in Ω has been compared to that …

Thermal Energy Storage Using High Temperature Borehole Heat Exchangers In Unconsolidated Materials, Kayla Bicknell

All Theses

Thermal energy storage is a potential method for storing excess energy produced when supply is greater than demand. The use of the subsurface for storing thermal energy has become more recognized as a viable alternative to conventional methods of energy storage. However, high temperature borehole thermal energy storage has yet to be researched in-depth. Therefore, the goal of this project is to determine the feasibility of using the subsurface to store thermal energy at relatively high temperatures.

The focus of this work is to determine what design elements would make a borehole thermal energy storage system most effective and produce …

Atomistic And Mesoscale Modeling Of Microstructure Development During Solid-State Sintering, Omar Hussein

All Dissertations

Interfaces are ubiquitous in materials systems, and they influence the processing and properties of nearly all engineering and functional materials. Examples include grain boundaries (GBs) in polycrystalline materials, free surfaces in nanoparticles, and phase boundaries in multiphase materials. Therefore, understanding and controlling interfacial processes is a key aspect of materials design and discovery efforts.

Recent developments in advanced manufacturing and synthesis techniques have enabled the fabrication of materials architectures with intricate nanoscale features. Of particular interest is solid-state sintering, known for creating complex and high-precision geometries with controlled microstructures. While sintering science has been the subject of active research, very …

Towards The Quantification Of Estrone And 17Β-Estradiol Conjugates In Dairy Cattle Urine Sorptive Stir Bar Extraction And Gas Chromatography-Mass Spectometry, S.M. Istiak Ahmed

Masters Theses & Specialist Projects

The global concern regarding the presence of compounds with estrogenic properties in the environment has grown significantly. Endocrine-disrupting compounds (EDCs) are environmental pollutants that disrupt the endocrine systems of both wildlife and humans. Estrogens, with their potent estrogenic effects, are particularly noteworthy among the various substances with endocrine-disrupting properties. They are of concern due to their prevalence in the environment, especially due to dairy waste contamination. These lipophilic compounds can accumulate in livestock fat tissues, potentially entering the human food chain. Sulfated forms of estrone and β- estriol, which exhibit a higher degree of saturation than their non-conjugated counterparts, have …

Adaptable Object And Animation System For Game Development, Isaiah Turner

Masters Theses & Specialist Projects

In contemporary times, video games have swiftly evolved into a prominent medium, excelling in both entertainment and narrative delivery, positioning themselves as significant rivals to traditional forms such as film and theater. The burgeoning popularity of gaming has led to a surge in aspiring game developers seeking to craft their own creations, driven by both commercial aspirations and personal passion. However, a common challenge faced by these individuals involves the considerable time investment required to acquire essential skills and establish a foundational framework for their projects. Accessible game development engines that offer a diverse range of fundamental features play a …

Characterization Of Interlayer Laser Shock Peening During Fused Filament Fabrication Of Polylactic Acid (Pla), Fabien Denise

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

The field of additive manufacturing (AM) has gained a significant amount of popularity due to the increasing need for more sustainable manufacturing techniques and the adaptive development of complex product geometries. The problem is that AM parts routinely exhibit flaws or weaknesses that affect functionality or performance. Over the years, surface treatments have been developed to compensate certain flaws or weaknesses in manufactured products. Combining surface treatments with the modularity of additive manufacturing could lead to more adaptable and creative improvements of product functions in the future. The current work evaluates the feasibility of pursuing a new research axis in …

The Self-Consistent Field Energy Landscape And Its Application To Describing Electron Correlation., Xinju (Spancer) Dong

Electronic Theses and Dissertations

Global elucidation of SCF (self-consistent-field) solutions is an extension of global optimization in which the goal is the identification of all solutions, which can be defined as a NP (nonpolynomial)-hard problem. The value of identifying multiple SCF solutions is to use as reference wavefunctions, such as NOCI (nonorthogonal configuration interactions), NOMCSCF (nonorthogonal multiconfigurational SCF), etc. However, the high-dimensional space over which to search and the relatively high cost of local optimization in Hartree-Fock (HF) models cause difficulty in efficiently searching over the full SCF space. In order to address the technical issues of high-dimensionality and nonlinearity, a Lie algebraic description …

Designing And Studying Redox-Active Molecules For Energy Storage And Desalination, Wenda Wu

All Graduate Theses and Dissertations, Fall 2023 to Present

Since the fast growth of the global population, energy scarcity has become a new threat to modern society. Those commonly seen resources like fossil, coal, and natural gas are nonrenewable energies, which cannot be replenished by human-scale time. In contrast, wind, solar, and hydropower are the three main renewable green energies under development with great efforts around the world. However, the intermittent character of these powers raises a new question: how to store them properly on large scales? By 2021, more than 90% of the electricity storage was taken by Lithium-ion batteries (LIBs). The usage of lithium brings concerns about …