Physical Sciences and Mathematics Commons^™

Assessing The Impact Of Parallel Burnout Fires On Flank Rate Of Spread, Erik Borke

Graduate Student Theses, Dissertations, & Professional Papers

The effects of flank-parallel suppression fires on the local rate of spread (ROS) of freely burning headfires through fully cured homogeneous grass fuels are assessed. Data sets include: one thermal image stack of a prescribed burn recorded by drone, and a suite of simulation experiments carried out in Wildland Urban Interface Fire Dynamics Simulator (WFDS). A new approach to computing ROS, curvature proxy driven normals to convex polylines, was developed to carry out this analysis. ROS time series depicting flank acceleration of the prescribed burn and simulation experiments, observable under coarse and fine directional classification schemes respectively, are the primary …

Displacement, Place Attachment, And Other Characteristics Of Anglers On The Yellowstone River, Zachary L. Jones

Graduate Student Theses, Dissertations, & Professional Papers

Yellowstone River has seen increasing recreational use as Montana has grown and out of state visitation has increased, leading to some locals voicing concerns of crowding. River recreation, as with many outdoor recreational activities, has participants that may be considered to be sensitive to crowded conditions and place a high value on solitude. Considering these perceptions, there is reason to believe that these participants may change their river use patterns if or when the perceived level of crowding exceeds their tolerance thresholds. Further, monitoring efforts conducted at river access sites often do not fully capture users that are already displaced …

Investigating Elastic Deformation Induced By Surface Loads On Planetary Bodies, Ashlesha Khatiwada, Hilary Martens, Donald F. Argus

Graduate Student Theses, Dissertations, & Professional Papers

Planetary bodies, including the Earth, deform when there is a redistribution of surface load. In this thesis, I conduct three independent projects related to surface loading, two of which investigate methods related to the modeling of surface loading and one which seeks to catalog the displacement responses of other planetary bodies to a surface load.

The first project aims to compare four methods for modeling the elastic loading response of the Earth: a homogeneous, non-gravitating, half-space method; a homogeneous, gravitating, spherical method; a homogeneous, non-gravitating spherical method; and a radially stratified gravitating spherical method. Many studies have focused on computing …

Climatological, Hydrological, And Economic Analysis Of Agriculture In Montana And The Western U.S.A., Zachary H. Lauffenburger

Graduate Student Theses, Dissertations, & Professional Papers

Many studies have addressed the impact of climate on agriculture; however, fewer studies addressed how farmers adapt to climate change, to what extent implementation of adaptation strategies mitigates economic losses or alters the hydrologic system. Analyses of how historical climate affected not only farmer decision making, but also the economic and hydrological consequences of farmers’ adaptations to climate variations, and projections of the spatiotemporal climatic regimes at finer regional scales are critical for aiding in actionable climate change adaptations. This dissertation helps fill knowledge gaps on the impacts of climate change in rural regions of the agricultural western U.S.A. and …

Evaluating The Sensitivity Of Crustal Deformation To Bedrock Hydrology In A Mountain Watershed, Brett J. Oliver

Graduate Student Theses, Dissertations, & Professional Papers

We evaluate the sensitivity of Earth's elastic deformation to groundwater hydraulic diffusivity using coupled groundwater and elastic deformation models. Seasonal changes in terrestrial water storage cause deformation to the Earth’s crust and deeper interior that is within the observational capacity of GPS instruments. We couple finite difference groundwater simulations with geodetic forward models of crustal displacement to investigate the ability of geodetic deformation to constrain bedrock hydrologic properties. We use MODFLOW-2005 to simulate seasonal changes in groundwater flow and storage, and then use the LoadDef elastic deformation model to forward model surface displacement caused by the change in terrestrial water …

N-Cylindrical Fuzzy Neutrosophic Topological Spaces, Sarannya Kumari R, Sunny Joseph Kalayathankal, Mathews George, Florentin Smarandache

Branch Mathematics and Statistics Faculty and Staff Publications

The objective of this study is to incorporate topological space into the realm of n-Cylindrical Fuzzy Neutrosophic Sets (n-CyFNS), which are the most novel type of fuzzy neutrosophic sets. In this paper, we introduce n-Cylindrical Fuzzy Neutrosophic Topological Spaces (n-CyFNTS), n-Cylindrical Fuzzy Neutrosophic (n-CyFN) open sets, and n-CyFN closed sets. We also defined the n-CyFN base, n-CyFN subbase, and some related theorems here.

Special Subset Linguistic Topological Spaces, Florentin Smarandache

Branch Mathematics and Statistics Faculty and Staff Publications

In this book, authors, for the first time, introduce the new notion of special subset linguistic topological spaces using linguistic square matrices. This book is organized into three chapters. Chapter One supplies the reader with the concept of ling set, ling variable, ling continuum, etc. Specific basic linguistic algebraic structures, like linguistic semigroup linguistic monoid, are introduced. Also, algebraic structures to linguistic square matrices are defined and described with examples. For the first time, non-commutative linguistic topological spaces are introduced. The notion of a linguistic special subset of doubly non-commutative topological spaces of linguistic topological spaces is introduced in this …

Interactions Of Bioactive Trace Metals In Shipboard Southern Ocean Incubation Experiments, Shannon M. Burns, Randelle M. Bundy, William Abbott, Zuzanna Abdala, Alexa R. Sterling, P. Dreux Chappell, Bethany D. Jenkins, Kristen N. Buck

OES Faculty Publications

In the Southern Ocean, it is well‐known that iron (Fe) limits phytoplankton growth. Yet, other trace metals can also affect phytoplankton physiology. This study investigated feedbacks between phytoplankton growth and dissolved Fe, manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), and cadmium (Cd) concentrations in Southern Ocean shipboard incubations. Three experiments were conducted in September–October 2016 near the West Antarctic Peninsula: Incubations 1 and 3 offshore in the Antarctic Circumpolar Current, and Incubation 2 inshore in Bransfield Strait. Additions of Fe and/or vitamin B₁₂ to inshore and offshore waters were employed and allowed assessment of metal (M) …

The Importance Of Winter Dinoflagellate Blooms In Chesapeake Bay— A Missing Link In Bay Productivity, Nicole C. Millette, Sophie Clayton, Margaret R. Mulholland, Leah Gibala-Smith, Michael Lane

OES Faculty Publications

It is widely assumed that phytoplankton abundance and productivity decline during temperate winters because of low irradiance and temperatures. However, winter phytoplankton blooms commonly occur in temperate estuaries, but they are often undocumented because of reduced water quality monitoring in winter. The small body of in situ work that has been done on winter blooms suggests they can be of enormous consequence to ecosystems. However, because monitoring is often reduced or stopped altogether during winter, it is unclear how widespread these blooms are or how long they can last. We analyzed an over 30-year record of monthly phytoplankton monitoring samples …

Atmospheric Input And Seasonal Inventory Of Dissolved Iron In The Sargasso Sea: Implications For Iron Dynamics In Surface Waters Of The Subtropical Ocean, Peter N. Sedwick, Bettina M. Sohst, K. N. Buck, S. Caprara, R. J. Johnson, D. C. Ohnemus, L. E. Sofen, A. Tagliabue, B. S. Twining, Tara E. Williams

OES Faculty Publications

Constraining the role of dust deposition in regulating the concentration of the essential micronutrient iron in surface ocean waters requires knowledge of the flux of seawater-soluble iron in aerosols and the replacement time of dissolved iron (DFe) in the euphotic zone. Here we estimate these quantities using seasonally resolved DFe data from the Bermuda Atlantic Time-series Study region and weekly-scale measurements of iron in aerosols and rain from Bermuda during 2019. In response to seasonal changes in vertical mixing, primary production and dust deposition, surface DFe concentrations vary from ∼0.2 nM in early spring to >1 nM in late summer, …

Sediment Delivery To Sustain The Ganges-Brahmaputra Delta Under Climate Change And Anthropogenic Impacts, Jessica L. Raff, Steven L. Goodbred Jr., Jennifer L. Pickering, Ryan S. Sincavage, John C. Ayers, Md. Saddam Hossain, Carol A. Wilson, Chris Paola, Michael S. Steckler, Dhiman R. Mondal, Jean-Louis Grimaud, Celine Jo Grall, Kimberly G. Rogers, Kazi Matin Ahmed, Syed Jo Grall, Kimberly G. Rogers, Kazi Matin Ahmed, Syed Humayun Akhter, Brandee N. Carlson, Elizabeth L. Chamberlain, Meagan Dejter, Jonathan M. Gilligan, Richard P. Hale, Mahfuzur R. Khan, Md. Golam Muktadir, Md. Munsur Rahman, Lauren A. Williams

OES Faculty Publications

The principal nature-based solution for offsetting relative sea-level rise in the Ganges-Brahmaputra delta is the unabated delivery, dispersal, and deposition of the rivers’ ~1 billion-tonne annual sediment load. Recent hydrological transport modeling suggests that strengthening monsoon precipitation in the 21st century could increase this sediment delivery 34-60%; yet other studies demonstrate that sediment could decline 15-80% if planned dams and river diversions are fully implemented. We validate these modeled ranges by developing a comprehensive field-based sediment budget that quantifies the supply of Ganges-Brahmaputra river sediment under varying Holocene climate conditions. Our data reveal natural responses in sediment supply comparable to …

Isotopic Evidence For Sources Of Dissolved Carbon And The Role Of Organic Matter Respiration In The Fraser River Basin, Canada, Britta M. Voss, Timothy I. Eglinton, Bernhard Peucker-Ehrenbrink, Valier Galy, Susan Q. Lang, Cameron Mcintyre, Robert G.M. Spencer, Ekaterina Bulygina, Zhaohui Aleck Wang, Katherine A. Guay

OES Faculty Publications

Sources of dissolved and particulate carbon to the Fraser River system vary significantly in space and time. Tributaries in the northern interior of the basin consistently deliver higher concentrations of dissolved organic carbon (DOC) to the main stem than other tributaries. Based on samples collected near the Fraser River mouth throughout 2013, the radiocarbon age of DOC exported from the Fraser River does not change significantly across seasons despite a spike in DOC concentration during the freshet, suggesting modulation of heterogeneous upstream chemical and isotopic signals during transit through the river basin. Dissolved inorganic carbon (DIC) concentrations are highest in …

Impact Of Atmospheric Correction On Classification And Quantification Of Seagrass Density From Worldview-2 Imagery, Victoria J. Hill, Richard C. Zimmerman, Paul Bissett, David Kohler, Blake Schaeffer, Megan Coffer, Jiang Li, Kazi Aminul Islam

OES Faculty Publications

Mapping the seagrass distribution and density in the underwater landscape can improve global Blue Carbon estimates. However, atmospheric absorption and scattering introduce errors in space-based sensors’ retrieval of sea surface reflectance, affecting seagrass presence, density, and above-ground carbon (AGC_seagrass) estimates. This study assessed atmospheric correction’s impact on mapping seagrass using WorldView-2 satellite imagery from Saint Joseph Bay, Saint George Sound, and Keaton Beach in Florida, USA. Coincident in situ measurements of water-leaving radiance (L_w), optical properties, and seagrass leaf area index (LAI) were collected. Seagrass classification and the retrieval of LAI were compared after empirical line …

Five Years Measuring The Muck: Evaluating Interannual Variability Of Nutrient Loads From Tidal Flooding, Alfonso Macías-Tapia, Margaret R. Mulholland, Corday R. Selden, J. Derek Loftis, Peter W. Bernhardt

OES Faculty Publications

Due to sea level rise, tidal flooding is now common in low-lying coastal systems around the world. Yet, the contribution of tidal flooding to non-point source nutrient loads and their impact on the quality of adjacent waters remains poorly constrained. Here, we quantified dissolved nutrient loading and Enterococcus abundance during annual autumnal king tides (i.e., perigean spring tides), between 2017 and 2021, in a sub-watershed of the lower Chesapeake Bay. To calculate nutrient loading from tidal flooding, we used geospatial inundation depths from a street-level hydrodynamic model to estimate floodwater volumes during each of the five sampling events and the …

Opioid Use Disorder Prediction Using Machine Learning Of Fmri Data, A. Temtam, Liangsuo Ma, F. Gerard Moeller, M. S. Sadique, K. M. Iftekharuddin, Khan M. Iftekharuddin (Ed.), Weijie Chen (Ed.)

Electrical & Computer Engineering Faculty Publications

According to the Centers for Disease Control and Prevention (CDC) more than 932,000 people in the US have died since 1999 from a drug overdose. Just about 75% of drug overdose deaths in 2020 involved Opioid, which suggests that the US is in an Opioid overdose epidemic. Identifying individuals likely to develop Opioid use disorder (OUD) can help public health in planning effective prevention, intervention, drug overdose and recovery policies. Further, a better understanding of prediction of overdose leading to the neurobiology of OUD may lead to new therapeutics. In recent years, very limited work has been done using statistical …

Systemic Analyses Of Radiocarbon Ages Of Coexisting Planktonic Foraminifera, Jörg Lippold, Julia Gottschalk, Jean Lynch-Stieglitz, Matthew W. Schmidt, Sönke Szidat, Andre Bahr

OES Faculty Publications

We compare radiocarbon (¹⁴C) ages of coexisting planktonic foraminifera species from sediment cores VM12-107 and KNR166-2-26JPC from the Equatorial Atlantic Ocean for three time periods (Holocene, Heinrich Stadial 1, last glacial maximum). We find a maximum inter-species difference of 1200 ¹⁴C yr. On average, the ¹⁴C ages deviate by ∼300 yr between Globigerinoides ruber and other species. In most cases, this exceeds the analytical uncertainty range of the measurements and thus renders the choice of species for generating age models as important as sample weight. While modern stratified water-column profiles imply an increase in ¹⁴C …

Sea Ice Formation, Glacial Melt And The Solubility Pump Boundary Conditions In The Ross Sea, Brice Loose, Sharon Stammerjohn, Peter Sedwick, Stephen Ackley

OES Faculty Publications

Seasonal formation of Dense Shelf Water (DSW) in the Ross Sea is a direct precursor to Antarctic Bottom Water, which fills the deep ocean with atmospheric gases in what composes the southern limb of the solubility pump. Measurements of seawater noble gas concentrations during katabatic wind events in two Ross Sea polynyas reveal the physical processes that determine the boundary value properties for DSW. This decomposition reveals 5–6 g kg⁻¹ of glacial meltwater in DSW and sea-ice production rates of up to 14 m yr⁻¹ within the Terra Nova Bay polynya. Despite winds upwards of 35 m s …

An Update On The Influence Of Natural Climate Variability And Anthropogenic Climate Change On Tropical Cyclones, Suzana J. Camargo, Hiroyuki Murakami, Nadia Bloemendaal, Savin S. Chand, Medha S. Deshpande, Christian Dominguez-Sarmiento, Juan Jesús González-Alemán, Thomas R. Knutson, I. I. Lin, Il- Ju Moon, Christina M. Patricola, Kevin A. Reed, Malcolm J. Roberts, Enrico Scoccimarro, Chi Yung Tam, Elizabeth J. Wallace, Liguang Wu, Yohei Yamada, Wei Zhang, Haikun Zhao

OES Faculty Publications

A substantial number of studies have been published since the Ninth International Workshop on Tropical Cyclones (IWTC-9) in 2018, improving our understanding of the effect of climate change on tropical cyclones (TCs) and associated hazards and risks. These studies have reinforced the robustness of increases in TC intensity and associated TC hazards and risks due to anthropogenic climate change. New modeling and observational studies suggested the potential influence of anthropogenic climate forcings, including greenhouse gases and aerosols, on global and regional TC activity at the decadal and century time scales. However, there are still substantial uncertainties owing to model uncertainty …

Acidification Of Northeastern Usa Lakes From Rising Anthropogenic-Sourced Atmospheric Carbon Dioxide And Its Effects On Aluminum Speciation, Karen H. Johannesson, Jaxon Dii Horne, Anant Misra, Catherine Aliperta, Orpheus V. Meletis, Robert C. Santore, Christopher D. White, Georgia Mavrommati, David J. Burdige

OES Faculty Publications

The impact of rising atmospheric CO₂ (pCO₂^atm) from anthropogenic activities on pH, dissolved inorganic carbon, carbonate mineral saturation, and aluminum (Al) speciation is evaluated for 18 northeastern USA lakes using polythermal, sliding activity reaction path models. pCO₂^atm was forced using two scenarios from the IPCC's Sixth Assessment Report in which pCO₂^atm attains either 600 or 1,100 ppm in 2,100. Results suggest pH will decrease 0.15 and 0.32 pH units, _aCO^2-₃ will decrease 24% and 49%, and Ω_aragonite will decrease 21% and 45%, respectively. These changes are of the same …

Evaluating Human Eye Features For Objective Measure Of Working Memory Capacity, Yasasi Abeysinghe, Enkelejda Kasneci (Ed.), Frederick Shic (Ed.), Mohamed Khamis (Ed.)

Computer Science Faculty Publications

Eye tracking measures can provide means to understand the underlying development of human working memory. In this study, we propose to develop machine learning algorithms to find an objective relationship between human eye movements via oculomotor plant and their working memory capacity, which determines subjective cognitive load. Here we evaluate oculomotor plant features extracted from saccadic eye movements, traditional positional gaze metrics, and advanced eye metrics such as ambient/focal coefficient , gaze transition entropy, low/high index of pupillary activity (LHIPA), and real-time index of pupillary activity (RIPA). This paper outlines the proposed approach of evaluating eye movements for obtaining an …

Hashes Are Not Suitable To Verify Fixity Of The Public Archived Web, Mohamed Aturban, Martin Klein, Herbert Van De Sompel, Sawood Alam, Michael L. Nelson, Michele C. Weigle

Computer Science Faculty Publications

Web archives, such as the Internet Archive, preserve the web and allow access to prior states of web pages. We implicitly trust their versions of archived pages, but as their role moves from preserving curios of the past to facilitating present day adjudication, we are concerned with verifying the fixity of archived web pages, or mementos, to ensure they have always remained unaltered. A widely used technique in digital preservation to verify the fixity of an archived resource is to periodically compute a cryptographic hash value on a resource and then compare it with a previous hash value. If the …

Cellbrf: A Feature Selection Method For Single-Cell Clustering Using Cell Balance And Random Forest, Yunpei Xu, Hong-Dong Li, Cui-Xiang Lin, Ruiqing Zheng, Yaohang Li, Jinhui Xu, Jianxin Wang

Computer Science Faculty Publications

Motivation

Single-cell RNA sequencing (scRNA-seq) offers a powerful tool to dissect the complexity of biological tissues through cell sub-population identification in combination with clustering approaches. Feature selection is a critical step for improving the accuracy and interpretability of single-cell clustering. Existing feature selection methods underutilize the discriminatory potential of genes across distinct cell types. We hypothesize that incorporating such information could further boost the performance of single cell clustering. Results

We develop CellBRF, a feature selection method that considers genes’ relevance to cell types for single-cell clustering. The key idea is to identify genes that are most important for discriminating …

Efficient Gpu Implementation Of Automatic Differentiation For Computational Fluid Dynamics, Mohammad Zubair, Desh Ranjan, Aaron Walden, Gabriel Nastac, Eric Nielsen, Boris Diskin, Marc Paterno, Samuel Jung, Joshua Hoke Davis

Computer Science Faculty Publications

Many scientific and engineering applications require repeated calculations of derivatives of output functions with respect to input parameters. Automatic Differentiation (AD) is a method that automates derivative calculations and can significantly speed up code development. In Computational Fluid Dynamics (CFD), derivatives of flux functions with respect to state variables (Jacobian) are needed for efficient solutions of the nonlinear governing equations. AD of flux functions on graphics processing units (GPUs) is challenging as flux computations involve many intermediate variables that create high register pressure and require significant memory traffic because of the need to store the derivatives. This paper presents a …

Enabling Customization Of Discussion Forums For Blind Users, Mohan Sunkara, Yash Prakash, Hae-Na Lee, Sampath Jayarathna, Vikas Ashok

Computer Science Faculty Publications

Online discussion forums have become an integral component of news, entertainment, information, and video-streaming websites, where people all over the world actively engage in discussions on a wide range of topics including politics, sports, music, business, health, and world affairs. Yet, little is known about their usability for blind users, who aurally interact with the forum conversations using screen reader assistive technology. In an interview study, blind users stated that they often had an arduous and frustrating interaction experience while consuming conversation threads, mainly due to the highly redundant content and the absence of customization options to selectively view portions …

Synthesis And Application Of Redox-Active Covalent Organic Frameworks In Rechargeable Batteries, Mohammad K. Shehab

Theses and Dissertations

Synthesis and Application of Redox-Active Covalent Organic Frameworks in Rechargeable Batteries

Mohammad K. Shehab

Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, United States

Abstract

In recent years, lithium-ion batteries (LIBs) have been considered the dominant energy storage devices for portable electronics and electric vehicles due to their high energy density, low self-discharge rate, and long cycle life. In LIBs, the traditional positive electrodes employed are mainly derived from metal-containing inorganic compounds composed of cobalt, iron, nickel, or manganese (LiCoO₂, LiMn₂O₄, and LiFePO₄) coupled with graphite as the negative electrode. Despite …

Characterizing Molecular Environments In Acrylic Paint Via Single-Sided Nmr, Lyndi Kiple

Dissertations, Theses, and Masters Projects

Acrylic paint is a modern artistic material made of colored pigment and polymeric binder. Acrylic binder requires fundamental study at the molecular level to understand its physical properties for purposes of art conservation and general polymer chemistry. The research presented in this thesis uses single-sided nuclear magnetic resonance (NMR) as a non-invasive and non-destructive way to measure relaxation and self-diffusion, which provide insight to molecular mobility and physical properties of proton-containing samples. Specifically, this study relies on T2 relaxation to gain insight to regions within acrylic paint with different molecular mobilities. In both dry and wet paint, relaxometry data revealed …

Biotic And Abiotic Factors Associated With Temporal And Spatial Variability Of Constitutive Mixotroph Abundance And Proportion, Marcella Dobbertin Da Costa

Dissertations, Theses, and Masters Projects

Mixotrophic protists, which combine the use of photosynthesis and prey ingestion to obtain nutrients for growth, comprise a substantial portion of the plankton community. However, there is a major gap in our understanding of how mixotroph prevalence varies spatially and temporally and under what conditions they dominate. I utilized a recently developed molecular technique to experimentally identify active mixotrophs (taxa identified to be grazing when samples were collected) and combined this with microscopy data to estimate active mixotroph abundance and proportion at two locations in a temperate estuary over a year. Active mixotroph abundance was compared to potential mixotroph (taxa …

Learning-Based Ubiquitous Sensing For Solving Real-World Problems, Woosub Jung

Dissertations, Theses, and Masters Projects

Recently, as the Internet of Things (IoT) technology has become smaller and cheaper, ubiquitous sensing ability within these devices has become increasingly accessible. Learning methods have also become more complex in the field of computer science ac- cordingly. However, there remains a gap between these learning approaches and many problems in other disciplinary fields. In this dissertation, I investigate four different learning-based studies via ubiquitous sensing for solving real-world problems, such as in IoT security, athletics, and healthcare. First, I designed an online intrusion detection system for IoT devices via power auditing. To realize the real-time system, I created a …

Climate Impacts On Spatiotemporal Habitat Usage Of Mid-Atlantic Fishes, Adena Jade Schonfeld

Dissertations, Theses, and Masters Projects

Climate change has altered marine environments, most notably by increasing water temperatures and reducing dissolved oxygen concentrations. These persistent changes have impacted the phenology and spatiotemporal habitat usage of mobile species, often through distributional shifts poleward or to deeper water. Climate-driven distributional shifts have been documented for numerous species inhabiting the Atlantic Ocean along the US East Coast, a region disproportionately affected by climate change. Adjacent estuaries are experiencing similar alterations to their physical environments and biotic community composition. Many estuarine species are seasonal residents and changes to environmental conditions within an estuary can result in altered usage and residence …

Development Of 3d And 360 Gis-Based Models To Visualize Projected Sea Level Rise In Coastal Virginia, Candice M. Vinson

Dissertations, Theses, and Masters Projects

Science communication is a skill that can be strengthened with practice. Like any skill, it helps to know what you need to practice in order to get better at it. When presenting information to an audience, the skill of science communication comes into play as early as the first draft of a presentation. As you think about how you will tell your story to the audience, you likely consider including text on slides, images, graphs, maps, or even videos. However, it is crucial to remember that accessibility barriers are something we must often consciously work to rid our presentations of, …