Digital Commons Network^™

Aquatic Habitat Representation For Robust Water Resources Management And Fish Conservation Decision-Making, Gregory C. Goodrum

All Graduate Theses and Dissertations, Fall 2023 to Present

We rely on rivers to provide water supply, flood control, and hydroelectricity for people and to sustain aquatic ecosystems. The development of dams and reservoirs to provide water for people did not consider environmental impacts to rivers, leading to widespread decline of freshwater species and habitat. Improving environmental outcomes of water management is needed to protect and restore aquatic ecosystems. However, rivers are complex and variable, making them difficult to represent as objectives for water management. This dissertation explores approaches to improve aquatic habitat representation and environmental objectives for water resources management and river conservation and restoration.

Chapter 2 uses …

Groundwater-Dependent Ecosystems In Southeastern Utah: An Integrated Analysis Of Hydrology, Ecology, And Landscape Change, Colten Lay

All Graduate Reports and Creative Projects, Fall 2023 to Present

In Southeastern Utah, springs play a critical role in sustaining groundwater-dependent ecosystems (GDEs) in a semi-arid environment. However, they remain understudied and face growing threats from climate change, land use modifications, and hydrologic alterations. This study addresses knowledge gaps in spring occurrence, hydrologic function, and ecological condition by integrating field surveys, remote sensing, and geospatial analysis across multiple spatial scales. It provides a comprehensive assessment of spring hydrology, water quality, and ecological conditions using field surveys, remote sensing, and GIS analysis to establish a foundational baseline of GDE resources in the region. I applied a multi-scale monitoring approach across the …

Onair: Applications Of The Nasa On-Board Artificial Intelligence Research Platform, Evana Gizzi, Conner Firth, Caleb Adams, James Berck, P. Timothy Chase Jr., Christian Cassamajor-Paul, Rachael Chertok, Lily Cloug, Jonathan Davis, Melissa De La Cruz, Matthew Dosberg, Alan Gibson, Jonathan Hammer, Ibrahim Haroon, Michael A. Johnson, Brian Kempa, James Marshall, Patrick Maynard, Brett Mckinney, Leyton Mckinney, Michael Monaghan, Robin Onsay, Hayley Owens, Sam Pedrotty, Daniel Rogers, Mahmooda Sultana, Jivko Sinapov, Bethany Theiling, Aaron Woodard, Caroline Zouloumian

Computer Science: Student Work

Infusing artificial intelligence algorithms into production aerospace systems can
be challenging due to costs, timelines, and a risk-averse industry. We introduce
the Onboard Artificial Intelligence Research (OnAIR) platform, an open-source
software pipeline and cognitive architecture tool that enables full life cycle AI
research for on-board intelligent systems. We begin with a description and user
walk-through of the OnAIR tool. Next, we describe four use cases of OnAIR for
both research and deployed onboard applications, detailing their use of OnAIR
and the benefits it provided to the development and function of each respective scenario. Lastly, we describe two upcoming planned deployments …

A Simple Guide For Describing Soils, 2nd Edition, Angela Stuart-Street, Nicolyn Short Dr, Paul Galloway, Noel R. Schoknecht

Natural resources published reports

Soils are enormously diverse and can be very confusing to understand and talk about. This simple guide for describing soils helps to identify the most important parts of a soil profile and provide an easy way to understand and explain what you see. It gives you a step-by-step guide of what soil properties to describe and how to describe them, along with the tools to make basic soil classifications. The soil descriptors help you to identify the soil type and aid in assigning a simple and standardised name to the soil. While this guide is designed to link with a …

Detection Of Activity Cliffs Produced By Anti-Cancer Drugs And An Algorithm For Reliable Predictions In Affected Areas, Sarah Josephine Aurit

Department of Statistics: Dissertations, Theses, and Student Research

An activity cliff (AC) occurs when drugs close in chemical space produce dissimilar biological results. We focus on developing an inferential procedure to detect the presence of ACs in a chemical landscape. If detected, we provide a distance-based procedure that can be used to identify regions of stability in the chemical landscape of interest and generate prediction with higher precision in those areas of stability. We conceptualize the chemical landscape as a spatial random field and use spatial models for prediction of efficacy for new drugs based on “distance” in chemical space. We argue that an AC manifests itself by …

Decoding Anisotropic Porous Medium: A Synergy Of Lattice Boltzmann Modelling And Operator Learning To Predict Permeability As A Function Of Orientation, Soumya Shouvik Bhattacharjee

Open Access Theses & Dissertations

Understanding the directional properties of porous media is essential for accurately predicting flow behavior, reactive transport, and fluid-solid interactions in systems ranging from geothermal reservoirs to energy storage devices and biological tissues. Directional variations in permeability - reflecting a medium's response to flow at different angular orientations - are particularly important for complex, inherently anisotropic geometries. In this study, we employ a Lattice Boltzmann (LBM) model to calculate directional permeabilities from porous media images subjected to varying flow inlet angles. Three classes of porous media were investigated: (1) synthetic media with circular grains, serving as isotropic baselines; (2) synthetic media …

Temporal Partitioning And Coexistence Among Four Sympatric Felid Species In The Northern Jaguar Reserve, Kylie Marie Rezendes

Open Access Theses & Dissertations

Coexistence among sympatric carnivores is shaped by behavioral strategies that mediate competition and mortality risk in heterogeneous landscapes. Understanding how sympatric carnivores, such as felids, use space and time in relation to one another requires models that account for both spatial and temporal overlap across landscapes. Models incorporating time-to-event probabilities provide a powerful framework for detecting behavioral dynamics across shared landscapes. This study evaluated the spatiotemporal responses of two apex predators â?? the jaguar (Panthera onca) and mountain lion (Puma concolor) - and two mesopredators - bobcat (Lynx rufus) and ocelot (Leopardus pardalis) - across five years of camera trap …

Experimental Investigation Of Photovoltaic Soiling Losses And Aerosol Absorption And Scattering Related To Dust In The Chihuahuan Desert Region, German Rodriguez Ortiz

Open Access Theses & Dissertations

This dissertation explores the interaction between mineral dust and solar radiation in the Chihuahuan Desert, one of the dustiest areas in North America. I focused on two main aspects: (1) the characterization of atmospheric aerosol optical properties during dust events, and (2) the effects of dust deposition (soiling) on the performance of photovoltaic (PV) modules. I characterized the intrinsic optical properties of aerosols in El Paso, Texas during the peak of the 2021 dust season. Ground-level, high-resolution optical and meteorological data were collected at the Black and Brown Carbon (BC^2) study site, whereas particulate matter and additional meteorological parameters were …

Laser Scan Path Design For Controlled Microstructure In Additive Manufacturing With Integrated Reduced-Order Phase-Field Modeling And Deep Reinforcement Learning, Augustine Twumasi

Open Access Theses & Dissertations

Laser Powder Bed Fusion (L-PBF) is a well-established additive manufacturing technique for fabricating intricate metal components with exceptional precision. A significant challenge in L-PBF is the formation of complex microstructures that influence final material properties. We propose a physics-guided, machine learning-aided approach to optimize scan paths for desired microstructure outcomes, such as equiaxed grains. We employed a phase-field method (PFM) to model the evolution of the crystalline grain structure. To reduce computational costs, we trained a surrogate machine learning model, a 3D U-Net convolutional neural network, using single-track phase-field simulations with varying laser powers to predict crystalline grain orientations based …

Optimal Hypergraph Connectivity With Cut Queries, Hang Liao

Dartmouth College Ph.D Dissertations

Finding connected components in undirected hypergraphs—hypergraph connectivity—is a fundamental problem in computer science. It can be framed as a special case of Symmetric Submodular Function Minimization (SSFM), where the objective is to determine if the non-trivial minimizer is zero. This thesis develops an optimal algorithm for hypergraph connectivity within the $\CUT$ query model, where an algorithm probes a subset of vertices to learn the weight of the hyperedges ``cut" by that partition.

Our approach is constructive, culminating in an optimal algorithm for the general problem by first developing the necessary tools for two foundational subproblems. The main contributions of this …

Arginine Vasotocin And Corticosterone In Nesting And Non-Nesting Loggerhead Sea Turtles In X’Cacel-X’Cacelito Sanctuary, Krista Blair Reed

Theses and Dissertations

Sea turtles exhibit distinct behaviors before and after egg laying, however, not all individuals successfully oviposit. Some females display disruptions in their typical nesting behavior, returning to the water without laying eggs, which is referred to as a non-nesting emergence (NNE). NNEs can be due to external disturbances on the beach, but why they occur is often unclear. Arginine vasotocin (AVT) is a neuropeptide involved in various physiological processes, including stimulating smooth muscle contraction of the oviduct to facilitate egg deposition in nesting sea turtles. On the other hand, corticosterone is the primary stress hormone in sea turtles and is …

Machine Learning Applications For Evaporation Predictions From Small Reservoirs: Potential Water Savings For Lower Rio Grande Valley, Texas, Syed Muhammad Fahad Abdullah

Theses and Dissertations

Local-scale reservoirs are important to regional water balance, but these are often overlooked. This study presents a robust machine learning (ML) approach leveraging reanalysis datasets to estimate daily evaporation for local-scale reservoirs in semi-arid South Texas. Selected models were trained with daily lake evaporation model (DLEM) estimates and used climatic and reservoir-specific properties as feature input variables. The multi-reservoirs training approach ensured applicable model generalization. Results show promising predictive performance with R² values ranging from 0.55–0.67 (testing) and 0.64–0.78 (validation), NSE values ranged from 0.54 0.67 (testing) and 0.64–0.78 (validation), and RMSE values ranged between 1.52–1.80 mm/day (testing) and 1.22–1.58 …

Oyster Shell Recycling Efforts In Horry County, Corabella Dieguez

Goal 14: Life Below Water

No abstract provided.

Reducing Single-Use Plastic In Georgetown County, Alex Gaspar

Goal 12: Responsible Consumption and Production

No abstract provided.

Sccosmix: A Mixed-Effects Framework For Differential Coexpression And Transcriptional Interactions Modeling In Single-Cell Rna-Seq, Anderson Bussing, Giampiero Marra, Daping Fan, Russell Shinohara, Danni Tu, Yen-Yi Ho

Faculty Publications

Advancements in single-cell RNA-sequencing (scRNA-seq) technologies generate a wealth of gene expression data that provide exciting opportunities for studying gene-gene interactions systematically at individual cell resolution. Genetic interactions within a cell are tightly regulated and often highly dynamic in response to internal cellular signals and external stimuli. Evidence of these dynamic interactions can often be observed in scRNA-seq data by examining conditional co-expression changes. Existing approaches for studying these dynamic interaction changes in scRNA-seq data do not address the multi-subject hierarchical design commonly considered in single-cell experiments. In this paper, we propose a Mixed-effects framework for differential Coexpression and transcriptional …

Mixture Effects On Metal Accumulation In The Asian Clam, Corbicula Fluminea, Mark A. Huff

Electronic Theses and Dissertations

Field collected Corbicula fluminea were exposed to trace level copper, lead, and zinc with the aim of examining the preferential accumulation between the soft tissue and shell. Metal levels were based on those in a permitted industrial effluent. At 1X effluent and 2X effluent exposure levels, copper was found to preferentially accumulate in the clam soft tissue, lead was found to preferentially accumulate in the clam shell, and zinc was found to excrete back into the diluent after preferentially accumulating in the clam soft tissue. When exposed as a mixture at 1X effluent levels, copper and lead were found to …

Training Robot Swarms For Adaptive Foraging In Environments With Obstacles, Pigar Biteng, Tameem Uz Zaman, Qi Lu

Computer Science Faculty Publications

In this work, we train adaptive and efficient foraging strategies for robot swarms in a large, unmapped search space with multiple randomly distributed box obstacles using the penalty-reward based NeuroEvolution of Augmented Topologies (NEAT), P-NeatFA. This model enables efficient multi-robot foraging behavior and obstacle avoidance by rewarding effective actions and penalizing inefficient ones, thereby minimizing redundant exploration and outperforming traditional stochastic foraging algorithms. We optimize foraging strategies and search patterns in robot swarms by training models that maximize cumulative rewards in three types of resource distribution environments. The evaluation focuses on the number of resources collected within a fixed time …

Insights Into The Radiation Chemistry Of Flash Radiation Therapy, Alan E. Lopez Hernandez

Dissertations and Theses (Open Access)

Purpose: FLASH radiation therapy (FLASH-RT) is an emerging modality that delivers radiation at ultra-high dose rates (UHDR) and has shown consistent normal tissue sparing while preserving tumor control compared to conventional RT—a phenomenon termed the FLASH effect. Despite promising results, the mechanisms behind the FLASH effect remain unclear. Many hypotheses point to radiolytic interactions, but experimental validation is limited. This work aims to develop a robust experimental platform to evaluate the relationship between radiolytic species production and physical beam parameters relevant to FLASH-RT, alongside dosimetry tools for reliable UHDR beam characterization.

Methods: A beam collector (BC) Faraday cup detector was …

Facilitating The Clinical Translation Of Flash Radiotherapy Through Dosimetry Development And Beam Parameter Optimization, Kevin Liu

Dissertations and Theses (Open Access)

Advisory Professor: Emil Schüler, PhD

Radiation therapy (RT) is a crucial component of curative cancer therapy, with a majority of cancer patients in the United States receiving RT as part of treatment. The goal of RT is to maximize the therapeutic index in curing disease while minimizing any associated normal-tissue complications¹. Recently, ultra-high dose-rate (UHDR) RT (mean dose rates ≥40 Gy/s for a total duration of ≤200 ms) has been reported to selectively spare normal tissues and organs while maintaining an isoeffective tumoricidal effect compared to conventional (CONV) dose rate RT in a variety of in vivo preclinical …

Drug Delivery, Disulfide Crosslinked Hydrogel Coating For Polydimethylsiloxane (Pdms) Implant Materials, Paul A. Contos, Paul Anthony Contos

Master's Theses

Though polydimethylsiloxane (PDMS) is often used in medical devices due to its desirable mechanical properties and biocompatibility, its surface is often prone to bacterial adhesion. This is especially a problem for catheters, where bacteria can adhere and form biofilms that can in turn result in Urinary Tract Infections (UTI). In order to deter the presence of UTI causing bacteria on PDMS catheters, methods were developed to formulate a disulfide crosslinked hydrogel coating and create a methodology to allow adhesion to a PDMS substrate. The hydrogel coating discussed in this paper will be synthesized by chemically crosslinking stimuli-responsive vesicles, that carry …

Influence Of Experience And Risk With Natural Hazards On Geoscience Interest And Career Expectations, Shannon Conner

All Dissertations

Understanding student interest in geoscience is important, as it has the potential to inform departmental decisions such as the selection of classroom examples and marketing strategies to attract new geoscience majors. Recruitment to geoscience is critical to address future social and environmental challenges. Our work may also provide insight into how to approach persistent recruitment problems within departments, such as student enrollment and the lack of diversity within the geosciences. This work involves developing a geoscience interest scale, integrating geospatial and educational data sets related to hazard risk and interest, and an exploring career motivations as related to natural hazard …

Melts To Solutions: Structure, Dynamics, And Response Of Polyelectrolytes, Shalika Meedin

All Dissertations

The current research elucidates the changes in the structure and motion of polyelectrolytes as they are perturbed by solvents and shear flows. Polyelectrolytes are macromolecules whose backbone consists of long, predominantly hydrocarbon chains, substituted by ionizable groups, which tend to dissociate into ions in polar solvents. Their properties result from a delicate balance of elastic energy that arises from the polymeric backbone and electrostatic forces, which stem from the ionizable groups. Though polyelectrolytes have an immense potential to propel numerous technologies, from clean energy to drug delivery systems, understanding the delicate balance between the properties of the polymer backbone and …

Crystal Structures Of Escherichia Coli Glucokinase And Insights Into Phosphate Binding, Joseph Andrews, Joshua Sakon, Chenguang Fan

Chemistry & Biochemistry Faculty Publications and Presentations

Here, we report the crystal structure of Escherichia coli glucokinase (GLK), which has phosphate bound in the cleft between the alpha and beta domains adjacent to the active site. A ternary complex consisting of GLK, glucose and phosphate is also reported in this work. Diffraction data were collected at 2.63 angstrom resolution for the phospate-bound form (R-work/R-free = 0.191/0.230) and at 2.54 angstrom resolution for the ternary complex (R-work/R-free = 0.202/0.258), both at 297 K. A B-factor analysis of the phosphate-bound GLK structure revealed consistently lower values for phosphate-interacting basic residues in the alpha 4, alpha 5 and alpha 9 …

Yizhi Sun: Profile Of The Newest Chbc Faculty Member., Danna Jaimes-Fajardo, Jeremy J. Smith, Lutishoor Salisbury

University Libraries Faculty Publications and Presentations

Presents the research profile of Yizhi Sun, Assistant Professor, Chemistry and Biochemistry department. It highlights his research interests, education, and impact of his research.

Roles Of Three Conserved Active Site Residues Of Cytochrome C Nitrite Reductases During The Early Steps Of Nitrite Reduction, Shahama Alam, Bradley J. Dimock, Brian Bennett, Steven J. Reinhardt, Shahid Shahid, A. Andrew Pacheco, Jarett Wilcoxen

Physics Faculty Research and Publications

Cytochrome c nitrite reductases (ccNiRs) catalyze reduction of nitrite to ammonium in a six-electron, eight-proton process. This report explores how the behavior of three active site ccNiR variants differs from that of the wild type enzyme (ccNiR_wt) in the presence of nitrite and a variety of electron donors. While the nitrite-loaded active site of Shewanella oneidensis ccNiR_wt could be 2-electron reduced within seconds to yield a 6-coordinate ferrous nitrosyl ({Fe(L)NO}⁷) at high applied potentials, quantitative reduction of the nitrite-loaded variants R103Q, H257Q, or Y206F required substantially stronger reductants and yielded a different product over several …

Enhancing The Value Of Satellite Earth Observations For Coastal Management: Tools For Collaboration And Co-Development, Nicole Dejeet Bartlett

Graduate Doctoral Dissertations

Despite unprecedented satellite Earth observation (EO) capabilities and free data availability, widespread adoption in coastal management remains limited due to persistent communication barriers between satellite experts and coastal practitioners. This dissertation addresses the fundamental challenge of translating satellite EO technical capabilities into management-relevant applications. Through synthesis of literature, stakeholder interviews, and two multi-year co-development case studies in Virginia's Middle Peninsula and Cape Cod, Massachusetts, this research identifies systematic barriers to satellite EO adoption and develops innovative frameworks for overcoming them.

The work argues for a common language between satellite product developers and coastal managers, identifying communication barriers spanning technical, institutional, …

Characterization Of Search Spaces And Effects On Machine Learning, Leo Ghelarducci

Doctoral Dissertations and Master's Theses

The present status of the field of Machine Learning (ML) focuses on optimization of popular models. Rarely are the effects of the problem characteristics upon the solution algorithm studied. There exists no standard for knowing when to apply ML algorithms to a given problem or how to estimate the effectiveness of results. Focusing on the search space of problems, a rigorous study was conducted to generate an in-depth understanding of the impact of search space characteristics to the performance of a ML algorithm, specifically a Genetic Algorithm (GA). The effects of specific problem characteristics, represented via solution space characteristics, on …

Drift Dynamics Of Early Life-Stage Invasive Carps, Saurav Karki

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

Asian carp species pose significant ecological threats to North American freshwater systems due to their invasive nature and prolific reproduction. Their semi buoyant eggs develop while drifting downstream with the river current. Understanding early life-stage transport is therefore critical for predicting recruitment potential and guiding management efforts. Existing fluvial egg drift models, including those relying on 1-D hydraulics and fully 3-D CFD-based models, are either inadequate for complex braided rivers or too computationally demanding for large-scale application. The Platte River in Nebraska, characterized by wide, shallow, multi-threaded channels, is dominated by two-dimensional flow conditions, making a depth-averaged 2-D modeling approach …

Authentication And Message Integrity Verification For Emerging Wireless Networks, Ebuka Philip Oguchi

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

This dissertation presents a comprehensive body of research on authentication and message integrity verification for emerging wireless networks, focusing on secret-free and physical layer security techniques across diverse, challenging, and unconventional environments.

It comprises four first-author contributions that span underground wireless systems, over-the-air (OTA) channels, vehicular communications, and nanoscale molecular networks.

The first contribution, Soil-Assisted Trust Establishment for Underground Wireless Networks (STUN), introduces a physical-layer trust bootstrapping protocol that achieves authentication and message integrity without pre-shared secrets. Leveraging underground-to-air propagation laws and trusted relay nodes, STUN resists active signal injection attacks and demonstrates security comparable to the unbalanced oil and …

Rhetorics Of Encounter: Toward A Biocentric Theory Of Discourse, Matthew D. Whitaker

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

Encounters with more-than-human identities are transformative moments that stand to affect dispositional and bodily change in individuals. From close brushes with wild animals in National Parks to everyday interactions with local ecologies, encounters invite us to feel and think differently about the nature of our realities. In Rhetorics of Encounter: Toward a Biocentric Theory of Discourse, I draw from interdisciplinary perspectives to disrupt the idea of rhetoric as a representational medium, arguing that rhetoric occurs not just through textual exchanges of words and symbols, but through embodied moments of contact with other responsive beings. Invoking George Kennedy’s theory …