Digital Commons Network^™

Untangling The Solar Wind And Magnetospheric Drivers Of The Radiation Belt Electrons, Simon Wing, Jay R. Johnson, Drew L. Turner, Aleksandr Y. Ukhorskiy, Alexander J. Boyd

Faculty Publications

Plain Language Summary

Many solar wind parameters correlate with one another, which complicates the causal-effect studies of solar wind driving of the magnetosphere. We use conditional mutual information, which is part of information theory, to untangle and isolate the effect of individual solar wind and magnetospheric drivers of the radiation belt electrons. For example, the solar wind density negatively correlates with electron phase space density (PSD) (average energy ∼1.6 MeV) with the response time lag of 15 hr. This has been attributed to the electron loss process such as magnetopause shadowing. The time lag suggests the time scale for this …

Why Capacity Market Prices Are Too High, Todd S. Aagaard, Andrew N. Kleit

Faculty Publications

The Federal Energy Regulatory Commission and regional transmission organizations have fixated on a concern that prices in electricity capacity markets are too low. In fact, however, capacity markets are significantly overpriced. The reason for this is that the administratively determined demand curves in capacity markets create conditions that procure far more electricity capacity than what is needed to meet reliability objectives. In particular, the operators of these markets systematically overestimate both the relevant peak demand for electricity and needed payments for generators to enter the market. The result is that consumer pay billions of dollars extra for excess capacity.

Aerial Radiation Detection Identification And Measurement System Detector Material Comparison Study, Benjamin C. Troxell, Kacey D. Mcgee, Christina L. Dugan

Faculty Publications

The 20th Chemical Biological Radiological Nuclear and Explosives Command (CBRNE) currently utilizes an airborne sodium iodide gamma and beta detection system to map radiation fields over large areas of interest. The 20th CBRNE explored emergent detector technologies utilizing two detection materials; thallium-activated cesium iodide and high purity germanium (HPGe). These detectors were simulated at various altitudes and compared to background measurements. The sodium iodide detector failed to provide isotopic discrimination at distance. The thallium-activated cesium iodide CsI(Tl) detector provided sufficient absolute efficiency and energy resolution to identify isotopics at distance. The HPGe detector provided the best energy resolution. However, current …

Augmenting Field Nuclear Forensics Capabilities With Handheld Atomic Spectroscopy Devices For Nuclear Debris Analysis, Ashwin P. Rao, Christopher M. Sutphin, Christina L. Dugan

Faculty Publications

The realm of technical nuclear forensics remains a critical part of joint counterproliferation capabilities. Since the passage of the Nuclear Forensics and Attribution Act (H.R.730) in 2010, the nuclear science community has undertaken steps to bolster national nuclear forensics capabilities under the National Technical Nuclear Forensics Center. Within the technical nuclear forensics umbrella, one particular area of interest involves developing capabilities for in-field analysis of nuclear material. This includes engaging in field training exercises across relevant branches of the military and investigating new technologies to conduct field nuclear forensic analyses. The integration of novel analytical technologies into real-world nuclear detection …

Pseudo-Modal Expansions For Generating Random Electromagnetic Beams, Milo W. Hyde Iv, Olga Korotkova

Faculty Publications

Excerpt: We derive two pseudo-modal expansions that provide insight into the structure of stationary electromagnetic sources and can be used for their physical realization and in computer simulations. Both expansions are derived from the vectorial version of Bochner’s theorem of functional analysis.

Obstructions To Shake Sliceness For Links, Anthony Bosman

Faculty Publications

Shake slice generalizes the notion of a slice link, naturally extending the notion of shake slice knots to links. There is also a relative version, shake concordance, that generalizes link concordance. We show that if two links are shake concordant, then their zero surgery manifolds are homology cobordant. Then we give several obstructions to a link being shake slice; for instance, the Arf invariants vanish for both the link and each component. Finally we show that a shake slice link bounds disjoint disks in a homology 4-ball and hence each component is algebraically slice.

Search For Gravitational Waves Associated With Gamma-Ray Bursts Detected By Fermi And Swift During The Ligo–Virgo Run O3b, Ligo Scientific Collaboration, Virgo Collaboration, Kagra Collaboration, Tiffany Z. Summerscales

Faculty Publications

We search for gravitational-wave signals associated with gamma-ray bursts (GRBs) detected by the Fermi and Swift satellites during the second half of the third observing run of Advanced LIGO and Advanced Virgo (2019 November 1 15:00 UTC–2020 March 27 17:00 UTC). We conduct two independent searches: a generic gravitational-wave transients search to analyze 86 GRBs and an analysis to target binary mergers with at least one neutron star as short GRB progenitors for 17 events. We find no significant evidence for gravitational-wave signals associated with any of these GRBs. A weighted binomial test of the combined results finds no evidence …

Evaluating Climatic Influences On The Technical Performance Of Built Infrastructure Assets, Sarah L. Brown, Steven J. Schuldt, Michael N. Grussing, Michael A. Johnson, Justin D. Delorit

Faculty Publications

Asset performance evaluations serve as a benchmark that can be used to make asset manufacturer selection decisions, i.e., choosing the brand of manufacturer that provides the highest performance among all brand competitors. Understanding the environmental conditions to which assets are subjected provides facility managers another data point to understand asset performance. This research builds upon a previously published performance-based manufacturer selection metric by investigating the linkage between asset performance and exposure to local climate, using chiller and air handler data from 20 United States Air Force installations. The link between environmental factors such as Heating Degree Days (HDD); Cooling Degree …

Possible Studies On Generalized Parton Distributions And Gravitational Form Factors In Neutrino Reactions, Shunzo Kumano, Roberto Petti

Faculty Publications

Spacelike and timelike generalized parton distributions (GPDs) have been investigated in charged-lepton scattering and electron-positron collisions via deeply virtual Compton scattering and two-photon processes, respectively. Furthermore, we expect that hadron-accelerator-facility measurements will be performed in future. The GPDs will play a crucial role in clarifying the origins of hadron spins and masses in terms of quarks and gluons. It is also possible to probe internal pressure within hadrons for understanding their stability. Gravitational form factors of hadrons used to be considered as a purely academic subject because gravitational interactions are too weak to be measured in microscopic systems. However, due …

Application Of Machine Learning To Predict The Performance Of An Emipg Reactor Using Data From Numerical Simulations, Owen Sedej, Eric G. Mbonimpa, Trevor Sleight, Jeremy Slagley

Faculty Publications

Microwave-driven plasma gasification technology has the potential to produce clean energy from municipal and industrial solid wastes. It can generate temperatures above 2000 K (as high as 30,000 K) in a reactor, leading to complete combustion and reduction of toxic byproducts. Characterizing complex processes inside such a system is however challenging. In previous studies, simulations using computational fluid dynamics (CFD) produced reproducible results, but the simulations are tedious and involve assumptions. In this study, we propose machine-learning models that can be used in tandem with CFD, to accelerate high-fidelity fluid simulation, improve turbulence modeling, and enhance reduced-order models. A two-dimensional …

Hiv-Related Stigma, Sexual Identity, And Depressive Symptoms Among Msm Living With Hiv: A Moderated Mediation Modeling Analysis, Tianyue Mi, Guanghua Lan, Xueying Yang Ph.D., Xiaoming Li Ph.D., Shan Qiao Ph.D., Zhiyong Shen, Yuejiao Zhou

Faculty Publications

Depression is one of the biggest health issues among men who have sex with men (MSM) living with HIV, where sexual identity might play an intricate role. Yet, findings of the relationship between sexual identity and depression were mixed and few studies explored its underlying mechanisms. This study aimed to examine the association between sexual identity and depression, and the potential mediating role of HIV-related stigma and moderating role of age. A cross-sectional survey was conducted among 203 MSM living with HIV in Guangxi, China. Participants provided information on sexual identity, depression, HIV-related stigma, and background information. Descriptive statistics, bivariate …

Developing An Optimized Policy Tree-Based Reservoir Operation Model For High Aswan Dam Reservoir, Nile River, Erfan Goharian, Mohamed Shaltout, Mahdi Erfani, Ahmed Eladawy

Faculty Publications

The impacts of climate change on the Nile River and Grand Ethiopian Renaissance Dam (GERD) along with the increased water demand downstream suggest an urgent need for more efficient management of the reservoir system that is well-informed by accurate modeling and optimization of the reservoir operation. This study provides an updated water balance model for Aswan High Dam Reservoir, which was validated using combined heterogeneous sources of information, including in situ gauge data, bias-corrected reanalyzed data, and remote sensing information. To investigate the future challenges, the spatial distribution of the annual/seasonal Aswan High Dam Reservoir surface air temperature trends over …

Developing An Optimized Policy Tree-Based Reservoir Operation Model For High Aswan Dam Reservoir, Nile River, Erfan Goharian, Mohamed Shaltout, Mahdi Erfani, Ahmed Eladawy

Faculty Publications

The impacts of climate change on the Nile River and Grand Ethiopian Renaissance Dam (GERD) along with the increased water demand downstream suggest an urgent need for more efficient management of the reservoir system that is well-informed by accurate modeling and optimization of the reservoir operation. This study provides an updated water balance model for Aswan High Dam Reservoir, which was validated using combined heterogeneous sources of information, including in situ gauge data, bias-corrected reanalyzed data, and remote sensing information. To investigate the future challenges, the spatial distribution of the annual/seasonal Aswan High Dam Reservoir surface air temperature trends over …

Image Classification Based On Sparse Representation In The Quaternion Wavelet Domain, Long H. Ngo, Nikolay Metodiev Sirakov, Marie Luong, Emmanuel Viennet

Faculty Publications

In this study, we propose a novel sparse representation learning method in the Quaternion Wavelet (QW) domain for multi-class image classification. The proposed method takes advantages from: i) the QW decomposition, which promotes sparsity and provides structural information about the image data while allowing approximate shift-invariance, to extract meaningful features from low-frequency QW subbands, ii) the dimensionality reduction method using Principal Component Analysis (PCA) for reducing the complexity of the problem, and iii) the sparse representation of the generated QW features to efficiently learn and capture the meaningful and compact information of this data. After the QW decomposition, the features …

Maintenance Cost Minimization Models For Offshore Wind Farms: A Systematic And Critical Review, Md Imran Hasan Tusar, Bhaba R. Sarker

Faculty Publications

Feasible and sustainable source of power is a burning question nowadays. The offshore wind farms can be a solution to power generation problem, but it is relatively more expensive. Its installation cost is more than twice of its similar size onshore counterpart. The cost that matters most is the operations and maintenance (O&M) cost. Expensive and sophisticated transfer vehicles as well as highly skilled technicians are needed to conduct O&M activities, which results in a remarkably higher O&M cost for an offshore wind farm project. Few researchers proposed some strategies that could resolve the problem nicely, although there is no …

Global Gnss-Ro Electron Density In The Lower Ionosphere, Dong L. Wu, Daniel J. Emmons Ii, Nimalan Swarnalingam

Faculty Publications

Lack of instrument sensitivity to low electron density (N_e) concentration makes it difficult to measure sharp N_e vertical gradients (four orders of magnitude over 30 km) in the D/E-region. A robust algorithm is developed to retrieve global D/E-region N_e from the high-rate GNSS radio occultation (RO) data, to improve spatiotemporal coverage using recent SmallSat/CubeSat constellations. The new algorithm removes F-region contributions in the RO excess phase profile by fitting a linear function to the data below the D-region. The new GNSS-RO observations reveal many interesting features in the diurnal, seasonal, solar-cycle, and magnetic-field-dependent variations in the …

Identifying Chemical Aerosol Signatures Using Optical Suborbital Observations: How Much Can Optical Properties Tell Us About Aerosol Composition, Meloe S. F. Kacenelenbogen, Qian Tan, Sharon P. Burton, Otto P. Hasekamp, Karl D. Froyd, Yohei Shinozuka, Andreas J. Beyersdorf, Luke Ziemba, Kenneth L. Thornhill, Jack E. Dibb, Taylor Shingler, Armin Sorooshian, Reed W. Espinosa, Vanderlei Martins, Jose L. Jimenez, Pedro Campuzano-Jost, Joshua P. Schwarz, Matthew S. Johnson, Jens Redemann, Gregory L. Schuster

Faculty Publications

Improvements in air quality and Earth's climate predictions require improvements of the aerosol speciation in chemical transport models, using observational constraints. Aerosol speciation (e.g., organic aerosols, black carbon, sulfate, nitrate, ammonium, dust or sea salt) is typically determined using in situ instrumentation. Continuous, routine aerosol composition measurements from ground-based networks are not uniformly widespread over the globe. Satellites, on the other hand, can provide a maximum coverage of the horizontal and vertical atmosphere but observe aerosol optical properties (and not aerosol speciation) based on remote sensing instrumentation. Combinations of satellite-derived aerosol optical properties can inform on air mass aerosol types …

Tutorial: Thermomechanical Constitutive Modeling Of Shape Memory Polymers, Cheng Yan, Guoqiang Li

Faculty Publications

Shape memory polymers (SMPs) are one of the intriguing functional materials and have been widely and intensively studied. In order to apply these new polymers to load bearing engineering structures and devices, developing physics-based thermomechanical constitutive models is mandatory. The aim of this Tutorial is to demonstrate how to establish a thermomechanical constitutive model for SMPs. It begins with classifications of SMPs, followed by a discussion on the underlying physics for different SMPs. After that, three classical SMP thermomechanical modeling frameworks are introduced, which include the visco-elasto-plastic based rheological framework, the storage strain-based phase transition framework, and the representative unit …

Television Viewing Time And All-Cause Mortality: Interactions With Bmi, Physical Activity, Smoking, And Dietary Factors, Christopher T. Swain, Julie K. Bassett, Allison M. Hodge, David W. Dunstan, Neville Owen, Yi Yang, Harindra Jayasekara, James R. Hébert Scd, Nitin Shivappa Mbbs, Mph, Ph.D., Robert J. Macinnis, Roger L. Milne, Dallas R. English, Brigid M. Lynch

Faculty Publications

Background Higher levels of time spent sitting (sedentary behavior) contribute to adverse health outcomes, including earlier death. This effect may be modified by other lifestyle factors. We examined the association of television viewing (TV), a common leisure-time sedentary behavior, with all-cause mortality, and whether this is modified by body mass index (BMI), physical activity, smoking, alcohol intake, soft drink consumption, or diet-associated inflammation. Methods Using data from participants in the Melbourne Collaborative Cohort Study, flexible parametric survival models assessed the time-dependent association of self-reported TV time (three categories: < 2 h/day, 2-3 h/day, > 3 h/day) with all-cause mortality. Interaction terms were fitted to test whether …

A Comparison Of Square-Wave Voltammetry Models To Determine The Number Of Electrons Exchanged In Metal Deposition, Ranon Fuller, Tyler Williams, Mark H. Schvaneveldt, Devin Rappleye

Faculty Publications

A comparison of square-wave voltammetry models for calculating the number of electrons exchanged in a metal deposition reaction. Experiments were conducted for silver deposition on platinum in an aqueous HNO₃ solution and for nickel and lanthanum deposition on platinum in molten LiCl. Diffusion coefficients for Ni²⁺ and La³⁺ in LiCl at 700^oC are calculated. Accuracy of soluble-soluble models versus a soluble-insoluble model is discussed. A simple method for determining the number of electrons exchanged under the constraint of well-compensated ohmic drop is proposed and evaluated.

Flood Depth Estimation During Hurricane Harvey Using Sentinel-1 And Uavsar Data, Sananda Kundu, Venkat Lakshmi, Raymond Torres

Faculty Publications

In August 2017, Hurricane Harvey was one of the most destructive storms to make landfall in the Houston area, causing loss of life and property. Temporal and spatial changes in the depth of floodwater and the extent of inundation form an essential part of flood studies. This work estimates the flood extent and depth from LiDAR DEM (light detection and ranging digital elevation model) using data from the Synthetic Aperture Radar (SAR)–Unmanned Aerial Vehicle Synthetic Aperture Radar (UAVSAR) and satellite sensor—Sentinel-1. The flood extent showed a decrease between 29–30 August and 5 September 2017. The flood depths estimated using the …

A Molecular Dynamics Study Of Monomer Melt Properties Of Cyanate Ester Monomer Melt Properties, Rebecca T. Haber, Andrea R. Browning, Bayleigh R. Graves, William P. Davis, Jeffrey S. Wiggins

Faculty Publications

The objective of this work was to computationally predict the melting temperature and melt properties of thermosetting monomers used in aerospace applications. In this study, we applied an existing voids method by Solca. to examine four cyanate ester monomers with a wide range of melting temperatures. Voids were introduced into some simulations by removal of molecules from lattice positions to lower the free-energy barrier to melting to directly simulate the transition from a stable crystal to amorphous solid and capture the melting temperature. We validated model predictions by comparing melting temperature against previously reported literature values. Additionally, the torsion and …

Connectivity And Directionality In Estuarine Channel Networks, Matthew Hiatt, Elisabeth A. Addink, Maarten G. Kleinhans

Faculty Publications

No abstract provided.

Constraints On Dark Photon Dark Matter Using Data From Ligo’S And Virgo’S Third Observing Run, Ligo Scientific Collaboration, Virgo Collaboration, Kagra Collaboration, Tiffany Z. Summerscales

Faculty Publications

We present a search for dark photon dark matter that could couple to gravitational-wave interferometers using data from Advanced LIGO and Virgo’s third observing run. To perform this analysis, we use two methods, one based on cross-correlation of the strain channels in the two nearly aligned LIGO detectors, and one that looks for excess power in the strain channels of the LIGO and Virgo detectors. The excess power method optimizes the Fourier transform coherence time as a function of frequency, to account for the expected signal width due to Doppler modulations. We do not find any evidence of dark photon …

Low Exposure Long-Baseline Neutrino Oscillation Sensitivity Of The Dune Experiment, A. Aduszkiewicz, J. Aguilar, Z. Ahmad, B. Aimard, B. Ali-Mohammadzadeh, T. Alion, K. Allison, S. Alonso Monnsalve, M. Alrashed, C. Alt, A. Alton, P. Amedo, J. Anderson, C. Andreopooulos, M. Andreotti, M. P. Andrews, F. Andrianala, S. Andringa, N. Anfimov, Roberto Petti, Sanjib R. Mishra Ph.D., Et. Al.

Faculty Publications

The Deep Underground Neutrino Experiment (DUNE) will produce world-leading neutrino oscillation measurements over the lifetime of the experiment. In this work, we explore DUNE’s sensitivity to observe charge-parity violation (CPV) in the neutrino sector, and to resolve the mass ordering, for exposures of up to 100 kiloton-megawatt-calendar years (kt-MW-CY), where calendar years include an assumption of 57% accelerator uptime based on past accelerator performance at Fermilab. The analysis includes detailed uncertainties on the flux prediction, the neutrino interaction model, and detector effects. We demonstrate that DUNE will be able to unambiguously resolve the neutrino mass ordering at a 4⁢𝜎 (5⁢𝜎) …

Measurement Of Structure Dependent Radiative K+ -> E,Sup>(+) Vy Gamma Decays Using Stopped Positive Kaons, H. Ito, A. Kobayashi, S. Bianchin, T. Cao, C. Djalali, D. H. Dongwi, T. Gautam, D. Gill, M. D. Hasinoff, K. Horie, Y. Igarashi, J. Imazato, N. Kalantarians, H. Kawai, S. Kimura, S. Kodama, M. Kohl, H. Lu, O. Mineev, Steffen Strauch, Et. Al.

Faculty Publications

The structure dependent radiative K + → e+νγ (K^SD+_e2γ) decay was investigated with stopped positive kaons. The e⁺ momentum spectra containing 574±30 K^SD+_e2γ events with a K + → μ+ν (K_μ2) background of 28 ± 19 events were measured with and without a photon in coincidence and analyzed with Monte Carlo simulations for acceptance and detector response to extract the ratio of the branching ratio of the K^SD+_e2γ decay and the K + → e+ν decay including the internal bremsstrahlung process (K_{e2(γ )}). …

Lakshadweep High Propagation And Impacts On The Somali Current And Eddies During The Southwest Monsoon, Paul A. Ernst, Bulusu Subrahmanyam, Corinne B. Trott

Faculty Publications

Climatological eddies in the Arabian Sea (AS), including the Lakshadweep High (LH) and the Great Whirl (GW), play major roles in the regional fluxes of upper ocean properties. For the first time, we apply an eddy tracking algorithm to the LH using altimetric sea surface height observations from 1993 through 2019. We additionally analyze the LH's water mass composition throughout its life cycle using the 1/12° Global eddy resolving physical ocean and sea ice reanalysis (GLORYS12). We observe that the second annual downwelling coastal Kelvin wave's (CKW) arrival during the winter monsoon is primarily responsible for generating the LH. In …

Determinants Of Covid-19 Vaccinations Among A State-Wide Year-Long Surveillance Initiative In A Conservative Southern State, Lídia Gual-Gonzalez, Maggie S.J. Mccarter, Kyndall Dye-Braumuller, Stella Self, Connor H. Ross, Chloe Rodriguez-Ramos, Virginie G. Daguise, Melissa Nolan Ph.D., Mph

Faculty Publications

By the end of 2021, the COVID-19 pandemic resulted in over 54 million cases and more than 800,000 deaths in the United States, and over 350 million cases and more than 5 million deaths worldwide. The uniqueness and gravity of this pandemic have been reflected in the public health guidelines poorly received by a growing subset of the United States population. These poorly received guidelines, including vaccine receipt, are a highly complex psychosocial issue, and have impacted the successful prevention of disease spread. Given the intricate nature of this important barrier, any single statistical analysis methodologically fails to address all …

Fast-Decaying Plant Litter Enhances Soil Carbon In Temperate Forests But Not Through Microbial Physiological Traits, Matthew E. Craig, Kevin M. Geyer, Katilyn V. Beidler, Edward R. Brzostek, Serita D. Frey, A. Stuart Grandy, Chao Liang, Richard P. Phillips

Faculty Publications

Conceptual and empirical advances in soil biogeochemistry have challenged long-held assumptions about the role of soil micro-organisms in soil organic carbon (SOC) dynamics; yet, rigorous tests of emerging concepts remain sparse. Recent hypotheses suggest that microbial necromass production links plant inputs to SOC accumulation, with high-quality (i.e., rapidly decomposing) plant litter promoting microbial carbon use efficiency, growth, and turnover leading to more mineral stabilization of necromass. We test this hypothesis experimentally and with observations across six eastern US forests, using stable isotopes to measure microbial traits and SOC dynamics. Here we show, in both studies, that microbial growth, efficiency, and …

Considerations For Radio Frequency Fingerprinting Across Multiple Frequency Channels, Jose A. Gutierrez Del Arroyo, Brett J. Borghetti, Michael A. Temple

Faculty Publications

Radio Frequency Fingerprinting (RFF) is often proposed as an authentication mechanism for wireless device security, but application of existing techniques in multi-channel scenarios is limited because prior models were created and evaluated using bursts from a single frequency channel without considering the effects of multi-channel operation. Our research evaluated the multi-channel performance of four single-channel models with increasing complexity, to include a simple discriminant analysis model and three neural networks. Performance characterization using the multi-class Matthews Correlation Coefficient (MCC) revealed that using frequency channels other than those used to train the models can lead to a deterioration in performance from …