Physical Sciences and Mathematics Commons^™

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

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

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

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

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, …

Mapping Climatic And Environmental Determinants Of Parasitic Helminth Prevalence In Southeast Asia, Angelica Avisado

UNLV Theses, Dissertations, Professional Papers, and Capstones

Climate change is reshaping environmental conditions across Southeast Asia (SEA) through rising temperatures, altered precipitation patterns, and increased droughts. These changes alter transmission dynamics of neglected tropical diseases (NTDs) by shifting spatial distribution, increasing larval development rates, faster pathogen growth development, and increasing transmission rates. NTDs are a group of preventable and treatable infections that disproportionately affect more than 1 billion people globally, specifically in tropical and subtropical regions. A subgroup of NTDs, parasitic helminth infections (PHIs) - particularly schistosomiasis, soil-transmitted helminths, and lymphatic filariasis remains a public health concern in the Southeast Asian region. PHIs and their ecological responses …

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 …

Geometric And Proximity Based Substrate Targeting By Cullin-Ring Ligases, Jerry Li

UNLV Theses, Dissertations, Professional Papers, and Capstones

Homeostasis, the process of maintaining stable biochemical and biophysical conditions, is a fundamental facet of cellular viability. Biochemical homeostasis is critical to support the biological functions that sustain living organisms. Protein ubiquitylation is one of the primary cellular pathways that regulate protein homeostasis and turnover. Ubiquitylation is initiated through the conjugation of a small globular protein known as ubiquitin, onto a given substrate. There exists a myriad of cellular fates that ubiquitylated proteins may undergo, but the most widely studied pathway is protein degradation, whereby a ubiquitylated protein substrate is shunted to a large macromolecular protease known as the proteasome, …

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 …

Characterization Of The Electronic Structure Of Metal–Organic Framework Mil-125 And Its Derivatives Using Soft X-Ray Spectroscopies, Jennifer Alexia Napoles

UNLV Theses, Dissertations, Professional Papers, and Capstones

Metal–organic frameworks (MOFs) are highly porous, three-dimensional networks composed of coordinated metal clusters and organic ligand subunits. While tens of thousands of MOFs have been synthesized, the Ti(IV)-based MOF MIL-125 has garnered scientific interest due to the observed changes to its optical and photocatalytic properties upon chemical modification. For example, upon UV irradiation in the presence of an alcohol, MIL-125 undergoes a photochromic color change to a photodoped state that has been associated with the storage of charge in the form of Ti(III) sites. Another example is exemplified by the amine group functionalization of the 1,4-benzenedicarboxylate (BDC) linker of MIL-125 …

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 …

Modeling The Mojave: A Multiphase, Mixed Methods Phenomenological Investigation Of Novice Understanding Of A Complex Ecological System, Nicole Juliana Thomas

UNLV Theses, Dissertations, Professional Papers, and Capstones

This research explores early college science majors’ conceptions of the Mojave Desert ecosystem as a complex system. A multi-level, explanatory sequential mixed methods design was employed to study college science majors’ understanding of the Mojave Desert ecosystem to better inform science pedagogy. The first level, the quantitative phase of the study, consisted of developing a mathematical representation of twelve ecosystem variables present within the Mojave Desert. The second level, the qualitative phase of the study, consisted of phenomenological semi-structured interviews with 23 early college science majors. The findings of this research suggest that the Mojave Desert operates as a complex, …

Enviromental Dna (Edna) Tools For Invasive Mosquitofish (Gambusia Affinis) Surveillance At The Shoshone Pupfish (Cyprinidon Nevadensis Shoshone) Refugium, Yusuf Olamilekan Umar

UNLV Theses, Dissertations, Professional Papers, and Capstones

Spring-fed aquatic ecosystems of the North American Southwest and U.S. Great Basin hosts a plethora of endemic fish species due to the effects of hydrologic fragmentation that resulted from Pleistocene aridification. Threats to endemic fishes worldwide include human intentional or unintentional release of exotic species into their habitats. Early detection of invasive species, while corrective actions are still possible, is critical for management, yet traditional survey methods are often disruptive to sensitive ecosystems, costly, and limited in sensitivity. The recent development of environmental DNA (eDNA) approaches offers powerful alternatives for invasive species monitoring in aquatic systems. In this study, a …

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

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, …

Towards Spatial Inversion Of Aerial Gamma-Ray Survey Data For Measurement Of Naturally Occurring Radioactivity, Daniel A. Haber

UNLV Theses, Dissertations, Professional Papers, and Capstones

Aerial gamma-ray surveying (AGRS) is used in geologic and environmental contexts to provide data on the surface spatial distribution of naturally occurring radioactive material (NORM) or other gamma-ray-emitting isotopes. The standard data reduction workflow for AGRS data involves a process whereby pointwise gamma-ray spectral data are denoised, corrected for numerous sources of background radiation and aircraft height, and are finally converted to physical values by empirical conversion factors. The reduced pointwise data are then typically spatially interpolated to form a continuous surface map.

This dissertation introduces and explores a novel spatial inversion method for reduced AGRS data that considers aircraft …

Integrating Post-Quantum Cryptography Into A Cdn-Style Pki: Tls And Quic Performance Across Pqc Suites, Katrina Mary Parsom

UNLV Theses, Dissertations, Professional Papers, and Capstones

Post-quantum cryptography (PQC) adds larger certificates and extra workload to the Transport Layer Security (TLS) handshake. In order to analyze the effect of that change on content delivery, a controlled testbed with conditions replicating a Content Delivery Network (CDN) is used. The system uses a standard X.509 certificate chain over TLS 1.3. It compares RSA with classical key exchange, RSA with hybrid key encapsulation mechanism (KEM), and Module Lattice-based Digital Signature Algorithm (ML-DSA) with hybrid KEM. The test harness generates and provides certificates and establishes TLS parameters. The test harness also supports mixed web workloads and records key metrics, including …

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. …

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 …

Gpu-Accelerated Effective Hamiltonian Calculator, Abhishek Chakraborty, Taylor L. Patti, Brucek Khailany, Andrew N. Jordan, Anima Anandkumar

Mathematics, Physics, and Computer Science Faculty Articles and Research

Effective Hamiltonian calculations for large quantum systems can be both analytically intractable and numerically expensive using standard techniques. In this manuscript, we present numerical techniques inspired by Nonperturbative Analytical Diagonalization (NPAD) and the Magnus expansion for the efficient calculation of effective Hamiltonians. While these tools are appropriate for a wide array of applications, we here demonstrate their utility for models that can be realized in circuit-QED settings. Our numerical techniques are available as an opensource Python package, qCHeff, which is available on GitHub (https://github.com/ NVlabs/qCHeff) and PyPI (https://pypi.org/ project/qcheff/). We use the CuPy library for GPU-acceleration …

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 …

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.

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

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 …

Fault Structure, Deformation Mechanisms, And Why Fault Zones Matter To Society, Elizabeth S. Petrie, David A. Ferrill, Kelly K. Bradbury, James P. Evans

Geosciences Faculty Publications

Faults are widespread geologic structures that form in sediment and all rock types, occur in all tectonic regimes, and can be a blessing or a curse to society. Faults and fault zones act as conduits for underground movement of water and as plumbing systems for aquifers and springs essential for human habitation in many semi-arid and arid regions worldwide. Faults also provide pathways for natural oil and gas migration and high-permeability zones in hydrocarbon reservoirs, as well as barriers contributing to trapping and reservoir compartmentalization. By enhancing permeability in many geothermal energy systems, faults can be essential for fluid circulation …

A Bump Hunting Approach To Finding Interpretable Data Pockets, Tushar Ojha

Electrical and Computer Engineering ETDs

This dissertation approaches the problem of extracting simple interpretations from local regions of data. This is sometimes called bump hunting because the local regions of interest have a high concentration of a particular output value. This work develops a bump hunting method for discrete-valued tabular data where each bump is modeled by a rectangular region of the input data space so its rule-based description admits a simple logical interpretation that can inform decisions. This method is designed for labeled data where each input feature has a distinct meaning that may or may not be related to the output, and the …

Kakeya Sets Over The Heisenberg Group, Gabriel Jacob Gress

Mathematics & Statistics ETDs

The Hausdorff dimension of Kakeya sets is an interesting problem where the two-dimensional case can be proven directly, but even obtaining bounds on the higher dimension analogues can require highly technical machinery. The difficulty of the general case has inspired analysts to look at Kakeya sets from non-Euclidean viewpoints.

In this paper, we explore a construction of the Kakeya set in the first Heisenberg group H^1. By utilizing the sub-Riemannian manifold of H^1 we can apply tools in geometric measure theory which at this time cannot be applied in R^3. We restate and provide a detailed proof for a sharp …

Dense Temporary Array Investigation Of Jemez Uplift Seismicity, Jillian D. Podmore

Earth and Planetary Sciences ETDs

A protracted multi-stage tectonic and magmatic evolution combined with low regional crustal strain rates make it challenging to characterize active structure that may host earthquakes in the Jemez Mountains of New Mexico. Here, we leverage temporary 1-month deployments of nodal seismometers to gain new insights into seismicity of the Jemez Mountains, which only have continuous seismic monitoring on their eastern flank as a result of the Los Alamos Seismic Network. Our catalog is built using 4 steps: phase picking in continuous seismic data, association of picks to detect unique events, event magnitude estimation, and absolute hypocenter estimation. We detect and …

Seismological Investigations Of Magmatic Systems Using Dense Nodal Arrays, Wenkai Song

Earth and Planetary Sciences ETDs

Understanding the internal architecture of magmatic systems is crucial for volcanology, yet conventional geophysical techniques often lack the resolution to image their fine-scale structures. This dissertation leverages unique datasets from dense nodal arrays to investigate the upper crustal magmatic systems beneath Yellowstone Caldera, Valles Caldera, and Mount St. Helens. At Yellowstone, I processed vibroseis data to delineate the top of the modern magma reservoir and evaluate the thermal connection between the magmatic and the overlying hydrothermal systems. At Valles, 3D radial seismic anisotropy imaging reveals strong positive radial anisotropy within the reservoir, indicating an organized structure of horizontally sill-like melt …

Assessment Of Fish Community Dynamics, Movement, And Morphology In Relation To Stream Barriers In The Upper Illinois Bayou Watershed, Risa Mccollough

ATU Theses and Dissertations 2021 - Present

Intermittent streams are increasingly recognized as vital components of river networks by supporting dynamic fish communities shaped by variable hydrology and habitat connectivity. They are becoming increasingly vulnerable to fragmentation by anthropogenic activities, namely road crossings, dams, and climate shifts that intensify seasonal drying. In response, I conducted two studies in the Illinois Bayou watershed in Arkansas to assess the effects of fragmentation on fish community dynamics and morphology in intermittent streams.

In the first study, I examined temporal fish community dynamics across two barriers: a natural waterfall in Dare Creek and a low-water crossing in Dry Creek. Simultaneously, I …