Physical Sciences and Mathematics Commons^™

Spectral Phase Pulse Shaping Alters Photoionization Time, James Aygun, Dany Yaacoub, Allison L. Harris

Faculty publications – Physics

Photoionization is a key step in many attosecond processes. Accurately determining the photoionization time delay is critical to understanding electron dynamics during and after ionization and can guide future efforts to manipulate electron motion. Prior studies have shown that the photoionization time delay is non-zero and that pulse shaping through alteration of the spectral phase may change the number and timing of ionization events. In order to assess whether and how the spectral phase modifies the photoionization time delay, we use attosecond streaking simulations to extract the streaking time delay for ionizing pulses with identical power spectra, but different spectral …

Climate Change Effects On Biomass And Greenhouse Gas Emissions Are Ameliorated By Nontoxic Endophytes In Southeastern Usa Transition Zone Tall Fescue Pastures, Rebecca Kay Mcgrail, Jonathan D. Moore, A. Elizabeth Carlisle, Jim A. Nelson, Rebecca L. Mcculley

Plant and Soil Sciences Faculty Publications

Background: The plant–microbe interaction between tall fescue and its endophyte Epichloë coenophiala can affect ecosystem responses to changing rainfall patterns and increasing temperatures. Endophyte-infected (E+) stands often exhibit improved stress tolerance and differing soil greenhouse gas (GHG) emissions compared to endophyte-free (E−) stands. However, it is unknown if mammalian nontoxic endophyte (NTE) strains introduced into some tall fescue cultivars confer differing stress tolerances or reduce soil GHG emissions.

Methods: We quantified the impact of fescue-NTE symbioses in Jesup and Texoma on biomass and GHG emissions in response to increased temperature (+3°C) and altered precipitation (50% lengthened interval between events) using …

A Global Synthesis Of Fragipan Silicon Concentrations And Relationships With Soil Physicochemical Properties As A Function Of Soil Parent Materials, Christopher Shepard

Plant and Soil Sciences Faculty Publications

Fragipans are dense, brittle subsurface horizons that restrict root growth and limit water-holding capacity. A common factor in these soils is a binding agent, potentially either phyllosilicate clay bridging, amorphous aluminosilicate/silica, or silica sorbed to Fe oxides. Others have suggested that no binding agent is present within these soil horizons and that the arrangement of individual particles is solely responsible for these horizons. In this article, a secondary data synthesis was utilized to demonstrate that silicon (Si) accumulation is a key pedogenic process in loess-derived fragipan horizons, but not in all fragipans. The average dithionite-extractable Si (Si_d) content …

Monitoring Long-Term Water Quality Benefits Of Urban Stream Restoration, Kira Burnett

2026 Research Poster Competition

Urbanization without conscious environmental planning can result in the degradation of stream ecosystems. This tends to result in urban stream syndrome, which is often characterized by increased sediment and nutrient concentrations, decreased biodiversity, more frequent flash flooding, and overall water quality degradation. As such, stream restoration practices are often implemented to address urban stream syndrome. Commonly used restoration practices include applying natural channel design to stabilize eroding stream banks and establishing diverse streamside vegetation to filter pollutant inputs. However, the benefits of restoration are not often quantified due to a lack of post-restoration monitoring, making it challenging to determine what …

Developing Bioassays For Detection Of Residual Herbicides In Compost, Esther Moore

2026 Research Poster Competition

Developing Bioassays for Detection of Residual Herbicides in Compost, the use of synthetic herbicides has dominated the field of agricultural production for over a century. While synthetic herbicide use has resulted in an undeniable boost in agricultural productivity, risks such as environmental degradation and reduced yield of non-target plant species must be considered. Key among these risks is compost contamination, especially from persistent herbicides. After these herbicides are applied, they are absorbed by growing vegetation, consumed by herbivores, passed through the digestive tract, and reintroduced into soil manure based compost. Even after this process, chemicals in such herbicides can remain …

Modeling The Development Of Keyhole Passage Morphology, Charlotte Boehme

2026 Research Poster Competition

Cave passage morphology is an important indicator of the hydrological conditions under which a cave passage was formed. Keyhole passages are a commonly occurring type of passage morphology that consists of a round, wide top with a smaller canyon incised in the bottom of the passage. These passages typically indicate a shift from fully water-filled to partially water-filled conditions. There are multiple mechanisms by which such a transition can occur, and little is understood about which of these mechanisms is most common, or whether aspects of keyhole passage morphology may indicate the primary formation mechanism. CaveCHAMP is a physically based …

Optimizing Microscale Tesla Valve Design For Enhanced Efficiency For Filtering And Sorting Bacteria, Brian Ewalt

2026 Research Poster Competition

Invented by Nikola Tesla in 1920, a Tesla valve is a passive check valve with no moving parts but showing diodicity for fluids (i.e., allowing fluids to flow easily in one direction but not in the other). Tesla valves have demonstrated remarkable versatility across a range of scientific fields. Recently, a study conducted at the University of Arkansas showed that these conduits exhibited diodicity for bacteria in the absence of fluid flows (Rogers et al. 2023), serving as proof of concept for applying microscale Tesla valves for filtering and sorting bacteria and microorganisms in biomedical settings. However, the design of …

Chronostratigraphy Using Stable Carbon Isotopes Of The Elliot Formation, South Africa, Aidan Del Pino

2026 Research Poster Competition

The Elliot Formation in South Africa preserves a fossil-bearing record spanning the Late Triassic–Early Jurassic, a time marked by significant environmental changes related to the Central Atlantic Magmatic Province (CAMP) and the end-Triassic extinction event. Despite its importance, the Elliot Formation remains poorly constrained due to limited chronostratigraphic markers. Chronostratigraphy is the branch of geology that correlates and dates rock units in time, allowing researchers to arrange these rock units into a chronological sequence. Globally, the Triassic–Jurassic boundary is characterized by a pronounced negative carbon isotope excursion linked to CAMP volcanism and the end Triassic extinction event. This C-isotope excursion …

Temporal Variational Graph Autoencoder For Influenza Evolution, Soumya Chauhan

2026 Research Poster Competition

Frequent mutations in influenza virus surface proteins can increase infectivity while evading human and vaccine immunity, causing seasonal epidemics. The CDC annually evaluates thousands of virus strains to predict mutated sequences likely to be dominant in the next season, which creates a need for methods that better capture how viral mutations evolve over time. In this study, we represent influenza protein sequences as a network-like graph, creating connections if sequences are collected a week apart and only differ by one mutation. This method explicitly considers time information as part of the evolution, while other existing methods analyze mutated sequences without …

Uav-Based Sensor Integration For In-Situ Lake Water Quality Monitoring, Alec Campbell

2026 Research Poster Competition

Current water quality assessment methods rely heavily on manual sampling and laboratory analysis, which are time-consuming and difficult to perform in remote or hazardous environments. In surface water monitoring, spatial and temporal resolution is often constrained by labor, access, and logistical limitations of manual sampling programs. This research aims to develop a drone-based system for real-time, in situ lake water quality monitoring. To address these challenges, the project focuses on integrating multiple water quality sensors, including oxidation-reduction potential (ORP), pH, electrical conductivity (EC), turbidity, and a multispectral spectrometer, into a compact, UAV-compatible design capable of collecting spatially referenced data. Methods: …

Flair- Flow-Level Anomaly Intrustion Recognition, Joseph Dumond

2026 Research Poster Competition

Industrial control systems (ICS) and industrial Internet of Things (IIoT) networks support critical infrastructure such as power generation, water treatment, and manufacturing. As these systems become more connected, they are increasingly exposed to cyber threats. However, many existing intrusion detection approaches rely on detailed packet inspection or supervised machine learning techniques that require labeled attack data and extensive tuning, making them difficult to deploy in real industrial environments.ICS networks typically generate highly regular and predictable communication patterns due to periodic control logic and deterministic device behavior. Because of this structure, abnormal or malicious activity often appears as a disruption to …

When Relevant Isn’T Readable: Evaluating Cognitive Accessibility In Search, Kaija Frierson

2026 Research Poster Competition

According to the World Health Organization, more than one billion people worldwide experience some form of disability. Many of them may affect cognitive processing and reading comprehension rather than vision or mobility, which creates barriers when accessing written information online. Web search is a critical modern literacy skill used for learning, decision-making, and everyday problem solving, yet most search systems are designed with the assumption that all users can process complex written language equally. As a result, people with dyslexia, other cognitive disabilities, low literacy levels, or who are English language learners may struggle to access relevant information even when …

P4 Driven Data Plane Analytics For Industrial Control Network Security, Haden Fowler

2026 Research Poster Competition

Industrial control systems manage critical infrastructure such as power grids, water treatment plants, and manufacturing facilities. These systems rely on specialized network protocols to send measurements and commands between sensors, controllers, and operator workstations. Protecting these networks from cyberattacks is essential because a successful intrusion could disrupt services that millions of people depend on daily. Most current security monitoring approaches analyze copies of network traffic after it has already passed through the system. This delay means that malicious commands may reach their targets before any alarm is raised. More importantly, when alerts do occur, operators often lack the evidence needed …

Solidfit: A Decentralized Mobile Health-Tracking App Using Personal Online Data Stores (Pods), Evan Meyers

2026 Research Poster Competition

Personal fitness data is increasingly collected through mobile applications, yet most current systems store this information in centralized platforms that limit user control, long-term ownership, and data portability. This project addresses the question of whether a decentralized data model can be used to support everyday fitness tracking while preserving user autonomy and privacy. As individuals become more aware of how their health data is collected and shared, there is a growing need for systems that allow users to retain ownership of their personal information without sacrificing usability or functionality.This research presents SolidFit, an Android-based fitness tracking application designed around the …

A Bayesian Late-Fusion Supportability Framework For Rare-Disease Severity Prediction In Glut1 Deficiency Syndrome, Jordan M. Rodriguez

Mathematics Dissertations

Glucose transporter type 1 deficiency syndrome (GLUT1-DS) is a rare neurometabolic disorder with heterogeneous neurological and developmental severity. Because patient-level severity is not observed as a single validated outcome, this dissertation develops a Bayesian late-fusion supportability framework for constructing and predicting an ordered latent severity phenotype from clinical, genetic, and EEG-derived evidence. The primary target was constructed in a larger clinical cohort using age-5 symptom burden and learning cognition, then assigned to an aligned multimodal prediction cohort. Target-defining variables were excluded from supervised predictors, and models were evaluated using patient-exclusive cross-validation with training-fold preprocessing and fold-wise EEG PCA.

The primary …

Comparative Evaluation Of Hplc And Capillary Electrophoresis In Intestinal Permeability Of Oseltamivir Phosphate Via Single-Pass Intestinal Perfusion (Spip) Method, Senem Şanli, Gülpembe Halay, Mustafa Sinan Kaynak, Nurullah Şanlı

Arts & Sciences Faculty Publications

Introduction: Oseltamivir phosphate (OP), a widely used antiviral prodrug for influenza, requires accurate Biopharmaceutics Classification System (BCS) classification to inform formulation and bioequivalence decisions. Despite its high solubility, the permeability characteristics of OP remain inadequately defined. Methods: This study evaluated the intestinal permeability of OP using the in situ Single-Pass Intestinal Perfusion (SPIP) model in male Sprague Dawley rats. Two validated analytical methods - High-Performance Liquid Chromatography (HPLC) and Capillary Zone Electrophoresis (CZE) were developed and compared. Metoprolol tartrate served as the high-permeability reference standard, and phenol red was used to monitor water flux. Permeability coefficients (Peff) were calculated after …

Propensity Score Matching Accounting For Longitudinal Trends Before Baseline With Group-Based Trajectory Modeling, Dustin R. Bastaich

Theses and Dissertations

Propensity score matching is used in observational studies to balance baseline attributes between a treatment of interest and a control group. Propensity score matching typically relies on baseline variables, but longitudinal trends in patient characteristics can also influence treatment decisions and subsequent health outcomes. This dissertation extends standard approaches by explicitly incorporating longitudinal trajectories of key variables into the propensity score estimation process.

Trends in a longitudinal variable prior to baseline were characterized using group-based trajectory modeling. A two-step modeling approach was implemented where trajectory groups of a key variable were first estimated and then included as covariates in the …

Identifying Mobility Hub Suitability In The Mid-Sized United States Urban Area Using Weighted Overlay And Percentile Based Local Peak Analysis, Eric Asplund

Theses and Dissertations

IDENTIFYING MOBILITY HUB SUITABILITY IN THE MID-SIZED UNITED STATES URBAN AREA USING WEIGHTED OVERLAY AND PERCENTILE‑BASED LOCAL PEAK ANALYSIS

By Eric Asplund

A thesis submitted in partial fulfillment of the requirements for the degree of Master of Urban and Regional Planning at Virginia Commonwealth University.

Virginia Commonwealth University, 2026.

Major Director: Dr. Ivan Suen, Ph. D., Associate Professor, Faculty of Urban and Regional Studies and Planning

Shared mobility hubs are increasingly posited in transportation planning as interventions supporting multimodality, sustainability, and equitable access, but guidance on evaluation of potential hub locations remains uneven, particularly in mid-sized United States cities where …

Environmental Monitoring In Shallow Lakes: Public Health Threats In Urban Waters, Kyleigh E. Johnson

Theses and Dissertations

Lakes are an integral part of urban and suburban communities, providing ecological, recreational, and public health benefits. Many of these lakes are located in densely populated areas and are subject to urban influences on water quality. Algal toxins and Escherichia coli are two common recreational concerns. Algal toxins come from harmful algal blooms that are influenced by nutrient availability and temperature, while bacteria are often introduced through run-off and animal waste. Sampling every 3-4 weeks from May-October 2025 allowed for the assessment of seasonal patterns and site-specific differences across nine lakes in the Richmond area. The highest bacterial concentrations appeared …

Evaluating Willow Establishment With Biochar For Remediation Of Mine Waste Soils: Amendment Ph Determines Plant Biomass And Metal Mobility, Madeline R. Webb

Dissertations, Master's Theses and Master's Reports

Heavy metal contaminated mine tailings (“stamp sands”) from historic copper mining inhibit plant establishment and contribute to ongoing metal contamination. Biochar amendments may enhance plant growth and reduce metal mobility in highly permeable mine waste soils, but the efficacies of different application methods or biochar sources and composition are uncertain. We evaluated different biochar sources (neutral or alkaline pH) and application methods (either mixed or layered) for planted willow growth, moisture retention, and metal mobility. A 10-week growth chamber experiment assessed plant performance, heavy metal content and heavy metal mobility in soil leachates and plant tissues. Biochar pH was the …

Origin Of The World-Class Eagle, Eagle East, And Tamarack Ni-Cu-Pge Deposits And Comparative Analysis With Other Midcontinent Rift- And Siberian Trap-Related Intrusions, Robert M. Nowak

Dissertations, Master's Theses and Master's Reports

The 1.1 Ga Mesoproterozoic Midcontinent rift hosts the Eagle, Eagle East, and Tamarack Ni-Cu-PGE deposits and Embayment Prospect. These deposits are hosted by ultramafic igneous rocks and have some of the highest Ni-Cu grades on Earth. We use new bulk-rock data and published datasets (bulk-rock, mineral chemistry, and isotopic analyses) to examine major, minor, and trace element trends of both Midcontinent rift-related alkaline and tholeiitic intrusions. In addition, we compare the geochemical data to local kimberlite-hosted lower-crustal xenoliths and local igneous (Archean) and sedimentary (Paleoproterozoic) country rocks. We found the peridotite magma compositions dominantly consist of primitive mantle compositions with …

Artificial Elections: How Artificial Intelligence Can Affect Elections And Decide Our Future, Ryan D. Granger

Honors Undergraduate Theses

This thesis examines the growing role of artificial intelligence (AI) in democratic elections, highlighting both its transformative potential and its associated risks. Drawing on a qualitative analysis of existing literature, the study explores how AI is increasingly integrated into political campaigns, election administration, and voter engagement. Key benefits include enhanced data analysis, personalized political messaging, and improved efficiency in campaign operations. AI also supports real-time fact-checking and more accurate vote tabulation, which can strengthen transparency and trust in electoral processes. However, the thesis emphasizes that these advantages are accompanied by significant challenges. AI technologies enable the rapid creation and dissemination …

Hybrid Patchtst And Physics-Based Framework For Predicting Lithium-Ion Battery State Of Health, Pavan Ravuri

Honors Undergraduate Theses

Accurately forecasting the state of health of lithium-ion batteries is critical for improving performance, reliability and lifetime in energy storage applications. Battery capacity degrades into a nonlinear pattern over cycling due to electrochemical processes where neither purely data driven nor physics-based models can capture alone. This study looks at a hybrid framework combining that PatchTST patch-based transformer architecture with physics-based features derived from the solid electrolyte interphase and pseudo two-dimensional models. Physics inspired proxy features were computed from cycling data and concatenated with electrochemical measurements as added input channels before patch segmentation. There are five model configurations that were evaluated …

Lie-Galois Theory, Giovanni Reed

Honors Undergraduate Theses

Differential equations are a much-studied topic in the field of mathematics, as well as other sciences, such as engineering, economics, and biology. While much is known concerning these, there is still a large gap in our knowledge about such equations. It is important therefore, both to mathematics and other sciences, that we gain a more complete knowledge of differential equations, in particular the nature of their solutions. In this research, we investigate the solution space of linear ordinary differential equations (ODEs) from the standpoint of differential algebra. Differential algebra allows an ODE to be treated similarly to a polynomial, allowing …

Dominating Hadwiger's Conjecture For 2k2-Free Graphs, Thomas Tibbetts

Honors Undergraduate Theses

A dominating K_t minor in a graph �� is a sequence (��₁,…,��_t) of pairwise disjoint non-empty connected subgraphs of ��, such that for 1≤��< ��≤��, every vertex in ��_j has a neighbor in ��_i. Replacing “every vertex in ��_j” by “some vertex in ��_j” retrieves the standard definition of a ��_t minor. The strengthened notion was introduced by Illingworth and Wood in 2024, who asked whether every graph with chromatic number �� contains a dominating ��_t minor. This is a substantial strengthening of the celebrated Hadwiger’s Conjecture, which asserts that every …

Balancing Evidence Recovery: Hexane’S Effect On Biological And Non-Biological Traces In Sexual Assault Kits, Maya Richards

Honors Undergraduate Theses

This study investigated the effectiveness of solvent – based extraction methods for the recovery of lubricant residues from simulated sexual assault swabs, with emphasis on balancing chemical evidence recovery. Sequential extraction using ultra – pure water followed by organic solvents, hexane, dichloromethane (DCM), and ethyl acetate (EA), was evaluated across water – based, silicone – based, oil – based, and hygiene product matrices. Analysis was performed using Direct Analysis in Real Time – High Resolution Mass Spectrometry (DART – HRMS), and extraction efficiency was assessed through spectral correlation with neat reference samples. Results demonstrated that solvent performance was highly dependent …

From Lap To Map: How Musical Scale, Place, And Play Drive The Interconnected Mario Kart World, Cameron Cummins

Honors Undergraduate Theses

With their deserts, castles, and ghost houses, the environments of Super Mario games are colorful, whimsical, and charming, but why are they so compelling, and what happens when our analysis of these environments extends beyond individual levels to expansive game worlds? Drawing on Cresswell’s theory of place (2014) and recent work on musical place-building in Mario Kart 8 (Heazlewood-Dale, 2024), I propose a spectrum between localized and globalized scale in games. As game environments become increasingly globalized, the music may be similarly altered to account for this shift in scale. Consequently, players may then encounter a broader, less musically congruent …

Evaluating The Comparison Of Different Body Locations For Data Collection Using Galvanic Skin Response Of Forensic Chemistry Students When In Lecture And Laboratory Environments, Elisa Guerrero

Honors Undergraduate Theses

Anxiety is the response that humans can have when exposed to a stimulus. It can be caused by a multitude of factors, such as psychological, biological, or physiological stimuli. Anxiety can be presented as a state or as a trait in a person. Trait anxiety is typically seen as a more stable personality trait, whereas state anxiety is a more intense temporary emotional state. In our study, anxiety was regarded as a more state-like characteristic. A galvanic skin response (GSR) Shimmer3+ device can measure skin electro-conductance changes following stimulation. In a situation where a participant is experiencing anxiety, levels of …

Ai-Assisted Hybrid Ga–Pso Channel Allocation Under 3gpp Tr 38.901 Uma For Efficient 5g Radio Resource Management, Sharada Narsingrao Ohatkar

ASEAN Journal on Science and Technology for Development

The increased traffic and heterogeneity in the 5G/B5G network require efficient radio resource management (RRM). However, the existing methods, such as GA and PSO, have poor convergence speed and require proper initial conditions. Additionally, learning-based methods have high computational complexity. Hence, in this paper, a novel AI-assisted Hybrid Channel Allocation (AI–HCA) framework is proposed by using a support vector regression (SVR)-based predictive initialization method and GA-PSO optimization. Simulation results using the 3GPP UMa channel model show that the proposed method has a 28% reduction in call blocking probability (CBP), a 15-25% enhancement in spectral efficiency (SE), and a 18-25% enhancement …

Sustainable Conductive Rpla-Carbon Black Filament For Additive Manufacturing Via Single-Screw Extrusion, Zaidan Faraby Zulkarnain, Shakina Hawapi, Aini Zuhra Abdul Kadir, Muhd Ikmal Isyraf Mohd Maulana, Nor Akmal Fadil, Najlaa Nazihah Mas’Ood, Mohd Rizal Alkahari, Saidin Wahab

ASEAN Journal on Science and Technology for Development

The growing demand for low-cost, sustainable conductive filaments for additive manufacturing motivates the exploration of recycled polymer feedstocks as alternatives to virgin materials. However, the effects of prior thermal reprocessing on both the electrical performance and morphological integrity of recycled PLA (rPLA)–carbon black (CB) composite filaments remain insufficiently characterised, particularly under single-screw extrusion conditions. This study fabricates and characterises conductive filaments from virgin PLA and rPLA, each loaded with CB at 0.2, 0.6, and 1.0 wt%, using a low-cost desktop single-screw extruder. Melt blending was found to be essential for achieving continuous filament extrusion, as ball milling produced insufficient filler …