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Full-Text Articles in Physical Sciences and Mathematics

Indigenizing Aquaculture: In Pursuit Of An Integrated Multi-Trophic Aquaculture System For Enhanced Self-Sufficiency In Akaroa Harbour, Aotearoa New Zealand, Cali R. Trainor Dec 2025

Indigenizing Aquaculture: In Pursuit Of An Integrated Multi-Trophic Aquaculture System For Enhanced Self-Sufficiency In Akaroa Harbour, Aotearoa New Zealand, Cali R. Trainor

Capstone Collection

This study assessed the feasibility of integrating two pre-existing aquaculture activities in Akaroa Harbour, Aotearoa New Zealand into an integrated multi-trophic aquaculture (IMTA) system. The cultivation of giant kelp (Macrocystis pyrifera) presents an opportunity to improve the sustainability of Chinook salmon (Oncorhynchus tshawytscha) farming by introducing alternative food sources for salmon, which can be used to produce fish feed locally, enhancing the self-sufficiency of the community and boosting the holistic efficiency of the system. Macroinvertebrates residing in giant kelp wrack were collected, identified, and quantified to determine if any of the Macrocystis-associated specimens could serve as …


Cv: Joseph Kozminski (Physics), Joseph Kozminski Dec 2025

Cv: Joseph Kozminski (Physics), Joseph Kozminski

Physics Department Faculty Curricula Vitae

No abstract provided.


Marine Heatwave Co-Occurrence Between Estuarine And Coastal Systems, Ricardo U. Nardi, Piero L. F. Mazzini, Ryan K. Walter Dec 2025

Marine Heatwave Co-Occurrence Between Estuarine And Coastal Systems, Ricardo U. Nardi, Piero L. F. Mazzini, Ryan K. Walter

Physics

Marine heatwaves (MHWs), prolonged periods of anomalously warm ocean temperatures, pose significant threats to marine ecosystems. While MHWs in coastal and estuarine systems have been studied separately, their spatial coherence remains significantly understudied. Here we analyze over 2 decades of high-frequency in situ temperature data from 54 stations across 20 U.S. estuaries and 13 coastal buoys to assess MHW co-occurrences. We find that estuarine and coastal MHWs co-occur only ∼21% of the time, a 57% decrease compared to co-occurrence within estuaries (∼49%). Maximum co-occurrence occurs at zero lag, suggesting synchronous synoptic-scale atmospheric forcing, likely via air–sea heat fluxes. Co-occurrence shows …


Is Ai Replacing Human Mental Health Professionals?, Michiko Ueda Dec 2025

Is Ai Replacing Human Mental Health Professionals?, Michiko Ueda

Population Health Research Brief Series

An increasing number of people are turning to generative artificial intelligence (AI) tools and AI-assisted chatbots to manage mental health concerns. This data slice presents findings from a national survey of U.S. adults aged 18-49 (N = 1,805) conducted in October 2025. Among respondents, 35.2% reported using AI tools more than once a week for mental health support. Among those who had ever seen a human mental health professional, 28.4% reported visiting human providers less often since beginning to use AI for the same purpose. The findings suggest that a subset of users may be using AI to replace, rather …


Regio- And Stereoselective Halogenation By An Iron(Ii)- And 2-Oxoglutarate-Dependent Halogenase In The Biosynthesis Of Halogenated Nucleosides, Philip M. Palacios, Xiaoyun Li, Simahudeen Bathir Jaber Sathik Rifayee, Haoyu Tang, Tatyana Karabencheva-Christova, Christo Christov, Wei-Chen Chang, Yisong Guo Dec 2025

Regio- And Stereoselective Halogenation By An Iron(Ii)- And 2-Oxoglutarate-Dependent Halogenase In The Biosynthesis Of Halogenated Nucleosides, Philip M. Palacios, Xiaoyun Li, Simahudeen Bathir Jaber Sathik Rifayee, Haoyu Tang, Tatyana Karabencheva-Christova, Christo Christov, Wei-Chen Chang, Yisong Guo

Michigan Tech Publications

Iron(II)- and 2-oxoglutarate-dependent (Fe/2OG) enzymes have garnered strong research interest in past decades due to their ability to catalyze regio- and stereoselective C-H functionalization via a single reactive intermediate, the oxyferryl species. In addition to the hydroxylation reaction that is commonly observed, other reaction outcomes have also been discovered in Fe/2OG enzymes. Among them, halogenation has attracted much research effort with the goal of revealing the molecular determinants to favor halogenation over hydroxylation however, a full mechanistic picture is still missing. In this study, by investigating a recently identified Fe/2OG halogenase, AdeV, from the biosynthetic pathway of Adechlorin, we show, …


Cloud-Top Entrainment Instability In Marine Stratocumulus Clouds: Observational Evidence From Collocated Microphysical, Turbulence, And Radiation Measurements, Inyeob La, Raymond Shaw, Holger Siebert, André Ehrlich, Jae Min Yeom, Seong Soo Yum Dec 2025

Cloud-Top Entrainment Instability In Marine Stratocumulus Clouds: Observational Evidence From Collocated Microphysical, Turbulence, And Radiation Measurements, Inyeob La, Raymond Shaw, Holger Siebert, André Ehrlich, Jae Min Yeom, Seong Soo Yum

Michigan Tech Publications

Marine stratocumulus clouds (MSC) strongly influence Earth's radiation budget, yet the mechanisms governing the descent of entrainment-affected (diluted) parcels, and the relative roles of cloud-top entrainment instability (CTEI) and longwave radiative cooling (RC), remain debated. Using helicopter-borne observations from the ACORES campaign that combine high-resolution in situ vertical profiling with co-located remote sensing, we examine vertical variations of microphysics, thermodynamics, and the entrainment interfacial layer (EIL). When CTEI conditions were strongly met, inhomogeneous mixing (IM) traits appeared near cloud top and transitioned to homogeneous mixing (HM) traits deeper in the cloud layer, accompanied by localized elevations of cloud base, signatures …


Predicting The Attitudes Towards Mathematical Modeling Of Primary Math Teachers: The Role Of Self-Efficacy And Motivation, Brenden Rawls Dec 2025

Predicting The Attitudes Towards Mathematical Modeling Of Primary Math Teachers: The Role Of Self-Efficacy And Motivation, Brenden Rawls

Doctoral Dissertations and Projects

The purpose of this non-experimental quantitative predictive correlational study was to investigate the extent to which efficacy for pedagogy in mathematics, efficacy for teaching mathematics content, effectance motivation in mathematics, years of experience, and access to statistics, data science, or mathematical modeling courses predict attitudes toward constructivist practices in mathematical modeling of Virginia primary school mathematics teachers. The goal of the research was to understand what affective characteristics support effective adoption Virginia's mathematics curriculum change. Higher levels of mathematics teacher self-efficacy have been associated with constructivist instructional practices and higher levels of student achievement. The sample included kindergarten through fifth-grade …


Insights From The Evolution Of Transport Technologies, 1800–2020: Energy Use, Transitions, And Efficiency, Bernardo Tostes, Matthew Kuperus Heun, Sofia T. Henriques, Paul E. Brockway, Tânia Sousa Dec 2025

Insights From The Evolution Of Transport Technologies, 1800–2020: Energy Use, Transitions, And Efficiency, Bernardo Tostes, Matthew Kuperus Heun, Sofia T. Henriques, Paul E. Brockway, Tânia Sousa

University Faculty Publications and Creative Works

The replacement of fossil fuels by electricity and other alternative fuels in transport will not be that sector’s first energy transition. Using transport history as an analogue for the future can offer helpful insights for today’s policymakers. The present work investigates the evolution of world energy use in the transport sector, identifying its energy transitions (at the final and useful stages), and evaluating the impact of past transitions on energy use over the period 1800–2020. To perform these analyses, a novel long-run dataset of energy use and efficiencies of water, rail, road, and air transport was developed. Our main findings …


Advancing Cybersecurity Practice: Explainable Machine Learning For Network Intrusion Detection, Adam Grabowski, Shengjie Xu Dec 2025

Advancing Cybersecurity Practice: Explainable Machine Learning For Network Intrusion Detection, Adam Grabowski, Shengjie Xu

Journal of Cybersecurity Education, Research and Practice

This research investigates explainable artificial intelligence (XAI) integration within machine learning (ML)-based intrusion detection systems (IDS), focusing on distinguishing malicious from benign network activities. We employed Random Forest and XGBoost models evaluated on widely recognized datasets, including NSL-KDD and UNSW-NB15, using both binary and multi-class classification tasks. The objective was to enhance cybersecurity operations through improved model transparency and interpretability. By integrating SHAP (SHapley Additive exPlanations) and LIME (Local Interpretable Model-Agnostic Explanations), the study offers comprehensive global and local insights into model decision-making processes. Results demonstrate SHAP's effectiveness in providing a broad, dataset-wide understanding of feature interactions and importance, while …


Cybercamp: An Experience Report On The Transformations Of An Intensive Cybersecurity Summer Camp For High School Students, Jose R. Ortiz Ubarri, Kariluz Dávila Diaz Ph.D., Rafael A. Arce Nazario Dec 2025

Cybercamp: An Experience Report On The Transformations Of An Intensive Cybersecurity Summer Camp For High School Students, Jose R. Ortiz Ubarri, Kariluz Dávila Diaz Ph.D., Rafael A. Arce Nazario

Journal of Cybersecurity Education, Research and Practice

The Cybercamp is a Cybersecurity summer camp for high school students that has been held for the last nine years at a Hispanic Serving Institution. Since its inception in 2016 the Cybercamp has undergone several transformations in response to budget reductions and the COVID pandemic, to finally become its current version: a rich, hands-on learning experience that we believe is easily replicable even in resource-challenged environments.

In this paper, we document the transformations of the Cybercamp and discuss the developed curriculum and materials in hopes that others will reuse, adapt, and improve upon them. In the Cybercamp, we apply active …


Clerodendrum Kelli (Lamiaceae), A New Species From Carranglan, Nueva Ecija, Philippines, And Lectotypification Of Clerodendrum Mindorense, David Justin R. Ples, Jacek Patykowski, John Charles A. Altomonte, Adriene B. Tobias, Rene Alfred Anton Bustamante Dec 2025

Clerodendrum Kelli (Lamiaceae), A New Species From Carranglan, Nueva Ecija, Philippines, And Lectotypification Of Clerodendrum Mindorense, David Justin R. Ples, Jacek Patykowski, John Charles A. Altomonte, Adriene B. Tobias, Rene Alfred Anton Bustamante

Biology Faculty Publications

Clerodendrum kelli (Lamiaceae), a new species from the montane forests of Carranglan, Nueva Ecija, Philippines, is described and illustrated. The species shares morphological features with Clerodendrum quadriloculare and C. mindorense, but differs in inflorescence structure, corolla tube length, and calyx shape and color. A lectotype for C. mindorense is also designated. Preliminary conservation assessment places C. kelli in the Critically Endangered category (CR B1ab(iii)+2ab(iii)). This study contributes to Philippine plant biodiversity knowledge and informs conservation strategies.


Assessment Of The Melt Quality Of A 30% Scrap Adc12 Aluminium Alloy Using The Inclusion And Fluidity Measurement Instrument (Ifmi) With Mullite Ceramic Filters, Gusti Ruri Ruri Lestari, Sandya Ananda Riswan, Muhammad Anis, Ahmad Ashari, Paramita Vidya Ayuningtyas, Bambang Suharno Prof, Donanta Dhaneswara Dec 2025

Assessment Of The Melt Quality Of A 30% Scrap Adc12 Aluminium Alloy Using The Inclusion And Fluidity Measurement Instrument (Ifmi) With Mullite Ceramic Filters, Gusti Ruri Ruri Lestari, Sandya Ananda Riswan, Muhammad Anis, Ahmad Ashari, Paramita Vidya Ayuningtyas, Bambang Suharno Prof, Donanta Dhaneswara

Journal of Materials Exploration and Findings

The increasing demand for sustainable practices in the metal casting industry has driven the use of recycled aluminum alloys such as ADC12. However, the addition of aluminum scrap tends to increase oxide inclusions, which reduce melt fluidity and compromise casting quality. This study utilizes the Inclusion and Fluidity Measurement Instrument (IFMI), equipped with mullite ceramic filters, to assess the melt quality of ADC12 aluminum alloy containing 30% scrap. Fluidity and inclusion characteristics were evaluated at five pouring temperatures (660°C, 680°C, 700°C, 720°C, and 740°C). The results show that fluidity increased with temperature, reaching a peak of 84.6 g·s⁻¹ at 740°C, …


Equipment Criticality Analysis To Determine Asset Integrity Management System Scheme In Supporting Production Optimization Scenarios In The Aeging Field, Donny Andryanto, Donanta Dhaneswara Dec 2025

Equipment Criticality Analysis To Determine Asset Integrity Management System Scheme In Supporting Production Optimization Scenarios In The Aeging Field, Donny Andryanto, Donanta Dhaneswara

Journal of Materials Exploration and Findings

This research investigates the production decline and cost increase in the X&Y oil and gas fields from 2022 to 2023. Production fell by 34%, while production costs per barrel rose by 79%. To address these issues, a series of optimization processes are proposed. These aim to restructure and enhance the production facilities to reduce current production costs. The optimizations include reducing pressure at the PPP Platform in 2024. Additional steps include shutting down CPP-ORF 14” pipelines and most processes at CPP 2 Platform by 2027 to convert it into an accommodation platform. Further, the plan involves optimizing the release of …


An Overview Of Biomass-Derived Graphene Oxide And Its Characteristics For Future Sustainable Applications, Afif Wardana, Ahmad Nabil Shahab, Donanta Dhaneswara, Nofrijon Sofyan Dec 2025

An Overview Of Biomass-Derived Graphene Oxide And Its Characteristics For Future Sustainable Applications, Afif Wardana, Ahmad Nabil Shahab, Donanta Dhaneswara, Nofrijon Sofyan

Journal of Materials Exploration and Findings

The production of graphene oxide (GO) from biomass presents considerable promise as a sustainable alternative substitute for traditional semiconductors. Biomass waste, abundant and often underutilized worldwide, is distinguished by its high carbon content and regenerative characteristics, rendering it an optimal resource for sustainable material production. By heating its biopolymers, lignocellulosic biomass can be used as a new material to make graphene, which forms three-dimensional turbostratic crystallites. These crystallites, composed of partially defective aromatic carbon sheets with graphite-like characteristics, make it easier to create GO with specialized functions for cutting-edge applications. Its capability underscores the revolutionary potential of biomass waste in …


Morphological Test Of Areca Nut Fiber Ceramic Membrane Using Scanning Electron Microscopy Energy Dispersive X-Ray Mapping Spectroscopy, Amelia Marzain, Siti Umi Kalsum, Marhadi Marhadi, Ahmad Nabil Shahab Dec 2025

Morphological Test Of Areca Nut Fiber Ceramic Membrane Using Scanning Electron Microscopy Energy Dispersive X-Ray Mapping Spectroscopy, Amelia Marzain, Siti Umi Kalsum, Marhadi Marhadi, Ahmad Nabil Shahab

Journal of Materials Exploration and Findings

This study investigates the potential of ceramic membranes derived from areca nut fiber as a cost-effective and environmentally sustainable material for the removal of iron (Fe) and manganese (Mn) from groundwater. Two types of membranes were fabricated: one without activation and one chemically activated using 10% sodium hydroxide (NaOH). The morphological and elemental characteristics of both membranes were analyzed using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) mapping. The concentrations of Fe and Mn before and after treatment were measured using Atomic Absorption Spectroscopy (AAS). The NaOH-activated membrane exhibited a more porous surface structure and higher oxygen content, …


Modeling Network Growth Via Generalized Isospectral Reductions, David Thomas Litster Dec 2025

Modeling Network Growth Via Generalized Isospectral Reductions, David Thomas Litster

Theses and Dissertations

Many real-world networks also exhibit a variety of symmetries. In this thesis we study equitable partitions and isospectral reductions, both of which are generalizations of symmetries. We formalize the relationship between these two types of generalized symmetry through the study of invariant subspaces. We then use recent results about the presence of equitable partitions in real-world networks to develop a network growth model that introduces similar structures, thereby introducing symmetries similar to those in real world networks.


Intrinsic Stability Of Controlled Systems Via Gershgorin-Type Estimates, David Friedbaum Dec 2025

Intrinsic Stability Of Controlled Systems Via Gershgorin-Type Estimates, David Friedbaum

Theses and Dissertations

Time delays are an inherent feature of real-world dynamical systems, arising whenever information, matter, or energy requires non-negligible time to propagate. Even small delays can destabilize systems that are otherwise well behaved, yet most standard control designs--such as PID or LQR--do not explicitly account for them and may fail when delays are present. This thesis investigates the stability of controlled dynamical systems subject to arbitrary time delays and develops new tools to determine when such systems remain stable. Our approach builds on the notion of intrinsic stability, a strong form of global stability introduced by Webb and Bunimovich, which guaranties …


Game-Theoretically Optimal Strategies In Baseball, William Michael Melville Dec 2025

Game-Theoretically Optimal Strategies In Baseball, William Michael Melville

Theses and Dissertations

Baseball players and their managers make numerous decisions that can have a significant effect on the result of the game. The effectiveness of their decision-making strategies depend on the strategies played by their opponents. For example, throwing a first-pitch fastball down the middle is a good strategy against a hitter who always takes the first pitch, but it is a risky strategy against a hitter who likes to swing at the first pitch and who is good at hitting fastballs. Additionally, any payoff a player receives from playing a strategy comes at the expense of their opponent. A batter cannot …


Play-Based Assessment Of The Cardinal Principle, Allyssa Sonnefeld Leavitt Dec 2025

Play-Based Assessment Of The Cardinal Principle, Allyssa Sonnefeld Leavitt

Theses and Dissertations

Gelman and Gallistel (1986) determined five counting principles that are essential for successful counting, including the cardinal principle where children understand that the last number counted represents the quantity of a set of objects. The traditional How many? task and the Give-n task are the most common tasks that have been used to assess whether children understand the cardinal principle. However, many researchers claim that these tasks either overestimate or underestimate children's understanding of the cardinal principle. Some researchers (Baroody & Pellegrino, 2023) suggest that embedding the traditional How many? task in a game may improve its validity. In this …


The Mechanics And Consequences Of The Löwenheim-Skolem And Compactness Theorems, Adam Murphy Dec 2025

The Mechanics And Consequences Of The Löwenheim-Skolem And Compactness Theorems, Adam Murphy

Honors Program Theses and Projects

The compactness theorem for first-order logic says that for a set of first-order sen-tences to be satisfiable, it’s enough for every finite subset to be satisfiable. We’ll see how the compactness theorem arises from two methods of model construction: first by ultraproducts, and second by Henkin’s method of constructing models from constant symbols. We’ll explore several representative applications of compactness, such as how it can be used to demonstrate that a property is not expressible, establishing limitations on first-order expressibility. The Löwenheim-Skolem theorem says that if an infinite set Γ of first-order sentences has an infinite model, then for all …


First-Principles Insights Into Binary Oxide Systems Under Extreme Pressure, Daniel Schacher Dec 2025

First-Principles Insights Into Binary Oxide Systems Under Extreme Pressure, Daniel Schacher

UNLV Theses, Dissertations, Professional Papers, and Capstones

Pressure is powerful tool by which one can manipulate the properties of materials. In this work we utilize pressure to explore binary oxide systems and characterize their structural and electronic properties. The observation of anomalous structural and electronic behavior in the rutile to CaCl2 phase transition in SnO2 led to the prediction that such behavior is inherent to all oxides experiencing such a phase transition sequence.[1] Here, the ultra-wide band gap semiconductor GeO2 is confirmed to exhibit anomalous behavior during the rutile to CaCl2 phase transition. A phase pure rutile GeO2 sample synthesized under high-pressure, high-temperature, conditions is probed using …


Ankimedbench: Evaluating Hierarchical Medical Knowledge In Language Model Embeddings, Neel Patel Dec 2025

Ankimedbench: Evaluating Hierarchical Medical Knowledge In Language Model Embeddings, Neel Patel

UNLV Theses, Dissertations, Professional Papers, and Capstones

Despite achieving over 90% accuracy on medical benchmarks, recent studies show physicians cannot effectively leverage language models to improve clinical reasoning. Current benchmarks test isolated factual recall, but clinical practice requires hierarchical navigation through diagnostic categories—starting broad and narrowing systematically from chest pain to cardiovascular pathology to myocardial infarction to specific STEMI types. Existing evaluations cannot measure whether models preserve this taxonomic structure essential for clinical reasoning.

We introduce AnkiMedBench, built from 16,512 medical flashcards used by students preparing for licensing exams. Cards are organized across six hierarchy levels spanning 16 broad medical specialties to 672 specific diseases and conditions. …


Re: Approval Letter For The Revised Draft Final Annual Operations And Maintenance (O&M) Report: Butte Treatment Lagoon (Btl) System - 2023 (Dated October 29, 2025), Emma Rott Dec 2025

Re: Approval Letter For The Revised Draft Final Annual Operations And Maintenance (O&M) Report: Butte Treatment Lagoon (Btl) System - 2023 (Dated October 29, 2025), Emma Rott

Silver Bow Creek/Butte Area Superfund Site

No abstract provided.


Stability Analysis Of Thermohaline Convection With A Time-Varying Shear Flow Using The Lyapunov Method, Kalin Kochnev Dec 2025

Stability Analysis Of Thermohaline Convection With A Time-Varying Shear Flow Using The Lyapunov Method, Kalin Kochnev

Honors Scholar Theses

This work applies the Lyapunov method to identify instabilities and compute the growth rate of a linear time-varying system. The linear system studied describes cold fresh water on top of hot salty water with a periodically time-varying background shear flow. A time-dependent weighting matrix is employed to construct a Lyapunov function candidate. The resulting linear matrix inequalities are discretized in time using the forward Euler method. As the number of temporal discretization points increases, the growth rate predicted by the Lyapunov method or Floquet theory, used for comparison, will converge to the same value obtained from numerical simulations. Furthermore, the …


Analysis Of Leakage In Nearshore Pipelines Using Fitness For Service Method To Ensure Mechanical Integrity Based On Api-579 Level 3, Elriandri Elriandri, Dedi Priadi Dec 2025

Analysis Of Leakage In Nearshore Pipelines Using Fitness For Service Method To Ensure Mechanical Integrity Based On Api-579 Level 3, Elriandri Elriandri, Dedi Priadi

Journal of Materials Exploration and Findings

The Fitness for Service (FFS) analysis is performed as a quantitative assessment to evaluate the integrity condition of a pipeline. Essentially, FFS assessment helps determine whether equipment components can operate safely despite existing deficiencies. This evaluation is carried out using the Finite Element Method (FEM). In the case of an underwater pipeline that experiences leak due to anchor pull at the flange connection, it undergoes plastic deformation and is lifted approximately 1 meter. As a mitigation step, inspection and repairs have been carried out by the company. Subsequently, modeling is performed to reconstruct the deformation process of the pipeline. Then, …


An Analysis Of Student Performance In Elementary Linear Algebra At Brigham Young University, Adrienne Irene Christensen Dec 2025

An Analysis Of Student Performance In Elementary Linear Algebra At Brigham Young University, Adrienne Irene Christensen

Theses and Dissertations

This study investigates different factors that influence performance in the Elementary Linear Algebra (ELA) course taught at Brigham Young University. These factors include student characteristics such as true freshman status and college enrollment, and content-specific factors such as how performance on essential topics affects overall performance in the course. To analyze the various research questions posed in the study, I used robust linear mixed effects models with random effects controlling for the hierarchical structure of the data. The statistically significant results from these models indicate that (i) true freshmen perform better than other students on exams and in the ELA …


Achieving More Accurate And Interpretable Fraud Detection With Double Machine Learning, Jeremy Andrew Berry Dec 2025

Achieving More Accurate And Interpretable Fraud Detection With Double Machine Learning, Jeremy Andrew Berry

Theses and Dissertations

Fraud detection remains a critical challenge across industries such as insurance, healthcare, finance, and government. Global losses from fraud and financial crime are estimated in the trillions annually, including billions in healthcare and insurance fraud alone. While effective for prediction, traditional machine learning methods often lack causal interpretability and struggle to adapt to evolving fraud tactics. This dissertation investigates the application of Double Machine Learning (DML), an emerging causal inference technique, to enhance both the accuracy and interpretability of fraud analytics. The research compares DML against established causal inference approaches, leveraging a meta-learning framework to evaluate model performance on accuracy, …


Quantifying Biocrust Evaporation In Arid Lands By Combining Thermal Imaging And Lysimeter Measurements, Rebekah C. Magness Dec 2025

Quantifying Biocrust Evaporation In Arid Lands By Combining Thermal Imaging And Lysimeter Measurements, Rebekah C. Magness

UNLV Theses, Dissertations, Professional Papers, and Capstones

Biological soil crusts (biocrusts) are miniature ecosystems of living organisms incorporated within the soil matrix and established in the topmost millimeters of the soil surface. Biocrust plays a critical role in the hydrologic processes in arid lands, yet the extent to which it increases or decreases evaporation remains unclear. To gain a better understanding of the impact of biocrust on evaporation compared to bare soil, I studied a cyanobacteria-dominated biocrust patch surrounded by bare soil atop a lysimeter in the Mojave Desert near Las Vegas, Nevada. Using high-resolution thermal imaging, and the known latent heat flux from the lysimeter, I …


Ultrafast Dynamics Of Two-Dimensional Electron Systems, Randy Michael Sterbentz Dec 2025

Ultrafast Dynamics Of Two-Dimensional Electron Systems, Randy Michael Sterbentz

UNLV Theses, Dissertations, Professional Papers, and Capstones

On-chip terahertz time-domain spectroscopy (THz-TDS) is a technique useful for measuring the ultrafast electrodynamics of two-dimensional (2D) electronic systems. Charge carrier collisions occur on the sub-picosecond time scale, and strongly correlated electron interactions (such as superconductivity) typically have energies on the order of milli-electron-volts. These phenomena fall within the terahertz bandwidth, which has historically been difficult to access. Commercial electronics operate with transistors capable of switching rates of around 100 GHz, while small band gap semiconductors (like InGaAs) can detect light down to 0.75 eV (180 THz). When combined with the difficulty of measuring 2D layered materials, with lateral sizes …


Shallow Groundwater Extraction Strategies In The Las Vegas Valley, Nevada, Teryl Stacey Dec 2025

Shallow Groundwater Extraction Strategies In The Las Vegas Valley, Nevada, Teryl Stacey

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Las Vegas Valley faces severe water scarcity due to Nevada’s limited Colorado River allocation and an arid climate. Population growth and prolonged drought have intensified these constraints, necessitating alternative resource strategies. This project evaluated a strategy to make use of brackish, shallow groundwater (from the top 30 feet below ground surface) located in the central and east-central parts of the valley. Its objective was to extract lower quality shallow groundwater for use as an alternative to fresh water currently being used for some applications that require little to no treatment. Dust suppression is among the most promising of such …