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Faculty Publications

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Full-Text Articles in Physical Sciences and Mathematics

Incorporating Oxygen Isotopes Of Oxidized Reactive Nitrogen In The Regional Atmospheric Chemistry Mechanism, Version 2 (Icoin-Racm2), Wendell W. Walter, Masayuki Takeuchi, Nga L. Ng, Meredith G. Hastings Jun 2024

Incorporating Oxygen Isotopes Of Oxidized Reactive Nitrogen In The Regional Atmospheric Chemistry Mechanism, Version 2 (Icoin-Racm2), Wendell W. Walter, Masayuki Takeuchi, Nga L. Ng, Meredith G. Hastings

Faculty Publications

The oxygen isotope anomaly (Δ17O = δ17O − 0.52 × δ18O > 0) has proven to be a robust tool for probing photochemical cycling and atmospheric formation pathways of oxidized reactive nitrogen (NOy). Several studies have developed modeling techniques to implicitly model Δ17O of NOy molecules based on numerous assumptions that may not always be valid. Thus, these models may be oversimplified and limit our ability to compare model Δ17O values of NOy with observations. In this work, we introduce a novel method for explicitly tracking Δ …


Flying Base Station Channel Capacity Limits: Dependent On Stationary Base Station And Independent Of Positioning, Sang-Yoon Chang, Kyungmin Park, Jonghyun Kim, Jinoh Kim Jun 2024

Flying Base Station Channel Capacity Limits: Dependent On Stationary Base Station And Independent Of Positioning, Sang-Yoon Chang, Kyungmin Park, Jonghyun Kim, Jinoh Kim

Faculty Publications

Flying base stations, also known as aerial base stations, provide wireless connectivity to the user and utilize their aerial mobility to improve communication performance. Flying base stations depend on traditional stationary terrestrial base stations for connectivity, as stationary base stations act as the gateway to the backhaul/cloud via a wired connection. We introduce the flying base station channel capacity to build on the Shannon channel capacity, which quantifies the upper-bound limit of the rate at which information can be reliably transmitted using the communication channel regardless of the modulation and coding techniques used. The flying base station’s channel capacity assumes …


Phase Error Scaling Law In Two-Wavelength Adaptive Optics, Milo W. Hyde Iv, Matthew Kalensky, Michael J. Spencer Jun 2024

Phase Error Scaling Law In Two-Wavelength Adaptive Optics, Milo W. Hyde Iv, Matthew Kalensky, Michael J. Spencer

Faculty Publications

We derive a simple, physical, closed-form expression for the optical-path difference (OPD) of a two-wavelength adaptive-optics (AO) system. Starting from Hogge and Butts’ classic OPD variance integral expression, we apply Mellin transform techniques to obtain series and asymptotic solutions to the integral. For realistic two-wavelength AO systems, the former converges slowly and has limited utility. The latter, on the other hand, is a simple formula in terms of the separation between the AO sensing (i.e., the beacon) and compensation (or observation) wavelengths. We validate this formula by comparing it to the OPD variances obtained from the aforementioned series and direct …


Heterogeneous Mantle Effects On The Behaviour Of Smks Waves And Outermost Core Imaging, Daniel A. Frost, Edward J. Garnero, Neala Creasy, Jonathan Wolf, Ebru Bozdağ, Maureen D. Long, Adeolu Aderoju, Reynaldo Vite Jun 2024

Heterogeneous Mantle Effects On The Behaviour Of Smks Waves And Outermost Core Imaging, Daniel A. Frost, Edward J. Garnero, Neala Creasy, Jonathan Wolf, Ebru Bozdağ, Maureen D. Long, Adeolu Aderoju, Reynaldo Vite

Faculty Publications

Seismic traveltime anomalies of waves that traverse the uppermost 100–200 km of the outer core have been interpreted as evidence of reduced seismic velocities(relative to radial reference models) just below the core–mantle boundary (CMB). These studies typically investigate differential traveltimes of SmKS waves, which propagate as P waves through the shallowest outer core and reflect from the underside of the CMB m times. The use of SmKS and S(m-1)KS differential traveltimes for core imaging are often assumed to suppress contributions from earthquake location errors and unknown and unmodelled seismic velocity heterogeneity in the mantle. The goal of this study is …


Advancing Objective Mobile Device Use Measurement Inchildren Ages 6–11 Through Built-In Device Sensors: A Proof-Of-Concept Study, Olivia L. Finnegan, Robert Glenn Weaver Med, Phd, Hongpeng Yang, James W. White, Srihari Nelakuditi, Zifei Zhong, Rahul Ghosal Ph.D., Yan Tong, Aliye B. Cepni, Elizabeth L. Adams, Sarah Burkart Mph, Ph.D., Michael W. Beets Med, Mph, Phd, Bridget Armstrong Ph.D. May 2024

Advancing Objective Mobile Device Use Measurement Inchildren Ages 6–11 Through Built-In Device Sensors: A Proof-Of-Concept Study, Olivia L. Finnegan, Robert Glenn Weaver Med, Phd, Hongpeng Yang, James W. White, Srihari Nelakuditi, Zifei Zhong, Rahul Ghosal Ph.D., Yan Tong, Aliye B. Cepni, Elizabeth L. Adams, Sarah Burkart Mph, Ph.D., Michael W. Beets Med, Mph, Phd, Bridget Armstrong Ph.D.

Faculty Publications

Mobile devices (e.g., tablets and smartphones) have been rapidly integrated into the lives of children and have impacted howchildren engage with digital media. The portability of these devices allows for sporadic, on-demand interaction, reducing theaccuracy of self-report estimates of mobile device use. Passive sensing applications objectively monitor time spent on a givendevice but are unable to identify who is using the device, a significant limitation in child screen time research. Behavioralbiometric authentication, using embedded mobile device sensors to continuously authenticate users, could be applied toaddress this limitation. This study examined the preliminary accuracy of machine learning models trained on iPad …


Perspective—Surface-Display Techniques In Electrochemical Biosensor Designs For Health Monitoring, Courtney J. Weber, Megan D. Whisonant, Olivia M. Clay, Olja Simoska May 2024

Perspective—Surface-Display Techniques In Electrochemical Biosensor Designs For Health Monitoring, Courtney J. Weber, Megan D. Whisonant, Olivia M. Clay, Olja Simoska

Faculty Publications

Enzymatic and microbial electrochemical biosensors integrate enzymes and microorganisms as biological recognition elements into the sensor design and functionality. Enzyme-based sensors offer high sensitivity and selectivity for target analyte detection. However, these have limited stability necessary for continuous analyte monitoring. Contrarily, microbe-based electrochemical sensors provide a means for continuous analyte sensing but are associated with challenges related to analyte selectivity in complex samples. To address these limitations, surface-display methods, which bind enzymes to microbial surfaces, enhance biosensor selectivity and sensitivity. This perspective outlines the application of surface-display techniques, offering a promising avenue for health monitoring.


Employing Digital Pcr For Enhanced Detection Of Perinatal Toxoplasma Gondii Infection: A Cross-Sectional Surveillance And Maternal-Infant Outcomes Study In El Salvador, Mary K. Lynn, Marvin Stanley Rodriguez Aquino, Pamela Michelle Cornejo Rivas, Xiomara Miranda, David F. Torres-Romero, Hanson Cowan, Madeleine M. Meyer, Willber D. Castro-Godoy, Mufaro Kanyangarara Ph.D., Stella Coker Watson Self Ph.D., Ms, Berry A. Campbell, Melissa Nolan Ph.D., Mph May 2024

Employing Digital Pcr For Enhanced Detection Of Perinatal Toxoplasma Gondii Infection: A Cross-Sectional Surveillance And Maternal-Infant Outcomes Study In El Salvador, Mary K. Lynn, Marvin Stanley Rodriguez Aquino, Pamela Michelle Cornejo Rivas, Xiomara Miranda, David F. Torres-Romero, Hanson Cowan, Madeleine M. Meyer, Willber D. Castro-Godoy, Mufaro Kanyangarara Ph.D., Stella Coker Watson Self Ph.D., Ms, Berry A. Campbell, Melissa Nolan Ph.D., Mph

Faculty Publications

Toxoplasma gondii is a parasitic infection that can be transmitted in utero, resulting in fetal chorioretinitis and other long-term neurological outcomes. If diagnosed early, pregnancy-safe chemotherapeutics can prevent vertical transmission. Unfortunately, diagnosis of acute, primary infection among pregnant women remains neglected, particularly in low-and-middle-income countries. Clinically actionable diagnosis is complex due to the commonality of infection during childhood and early adulthood which spawn long-last antibody titers and historically unreliable direct molecular diagnostics. The current study employed a cross-sectional T. gondii perinatal surveillance study using digital PCR, a next generation molecular diagnostic platform, and a maternal-fetal outcomes survey to ascertain …


Improving 2–5 Qubit Quantum Phase Estimation Circuits Using Machine Learning, Charles Woodrum, Torrey J. Wagner, David E. Weeks May 2024

Improving 2–5 Qubit Quantum Phase Estimation Circuits Using Machine Learning, Charles Woodrum, Torrey J. Wagner, David E. Weeks

Faculty Publications

Quantum computing has the potential to solve problems that are currently intractable to classical computers with algorithms like Quantum Phase Estimation (QPE); however, noise significantly hinders the performance of today’s quantum computers. Machine learning has the potential to improve the performance of QPE algorithms, especially in the presence of noise. In this work, QPE circuits were simulated with varying levels of depolarizing noise to generate datasets of QPE output. In each case, the phase being estimated was generated with a phase gate, and each circuit modeled was defined by a randomly selected phase. The model accuracy, prediction speed, overfitting level …


Development Of An Experimentally Validated Computational Fluid Dynamics Model For A Pbi Membrane-Based Anhydrous Hcl Electrolyzer, Kris Likit-Anurak, Hunter R. Teel, Ishwor Karki, Ben I. Howard, Brian C. Benicewicz, Sirivatch Shimpalee, Benjamin H. Meekins May 2024

Development Of An Experimentally Validated Computational Fluid Dynamics Model For A Pbi Membrane-Based Anhydrous Hcl Electrolyzer, Kris Likit-Anurak, Hunter R. Teel, Ishwor Karki, Ben I. Howard, Brian C. Benicewicz, Sirivatch Shimpalee, Benjamin H. Meekins

Faculty Publications

We report the development of an experimentally-validated computational fluid dynamics (CFD) model for simulation of an anhydrous HCl electrolyzer. The experimental data from 3 membrane variants was used to provide kinetic and membrane parameters for the model. The model not only accurately simulates overall electrolyzer performance, but it also provides key insights into the transport phenomena within the electrolyzer. The model allows simulation of experimental parameters like high HCl flowrates and increased cell pressure that pose a high safety risk to researchers. The model shows hotspots in the temperature distribution that will need to be addressed by flow field modification …


Analysis Of Modeled 3d Solar Magnetic Field During 30 X/M-Class Solar Flares, Seth H. Garland, Vasyl B. Yurchyshyn, Robert D. Loper, Benjamin F. Akers, Daniel J. Emmons Ii May 2024

Analysis Of Modeled 3d Solar Magnetic Field During 30 X/M-Class Solar Flares, Seth H. Garland, Vasyl B. Yurchyshyn, Robert D. Loper, Benjamin F. Akers, Daniel J. Emmons Ii

Faculty Publications

Using non-linear force free field (NLFFF) extrapolation, 3D magnetic fields were modeled from the 12-min cadence Solar Dynamics Observatory Helioseismic and Magnetic Imager (HMI) photospheric vector magnetograms, spanning a time period of 1 hour before through 1 hour after the start of 18 X-class and 12 M-class solar flares. Several magnetic field parameters were calculated from the modeled fields directly, as well as from the power spectrum of surface maps generated by summing the fields along the vertical axis, for two different regions: areas with photospheric |Bz|≥ 300 G (active region—AR) and areas above the photosphere with the …


Quantification Of Surface Layer Turbulence Using Sensible Heat Values From Energy Balance Versus Aerodynamic Methods, Steven T. Fiorino, Yogendra Raut, Jaclyn Schmidt, Laura Slabaugh, Blaine Fourman, Jack E. Mccrae, Benjamin C. Wilson, Santasri R. Bose-Pillai May 2024

Quantification Of Surface Layer Turbulence Using Sensible Heat Values From Energy Balance Versus Aerodynamic Methods, Steven T. Fiorino, Yogendra Raut, Jaclyn Schmidt, Laura Slabaugh, Blaine Fourman, Jack E. Mccrae, Benjamin C. Wilson, Santasri R. Bose-Pillai

Faculty Publications

Surface layer optical turbulence values in the form of the refractive index structure function C_n^2 are often calculated from surface layer temperature, moisture, and wind characteristics and compared to measurements from sonic anemometers, differential temperature sensors, and imaging systems. A key derived component needed in the surface layer turbulence calculations is the sensible heat value. Typically, the sensible heat is calculated using the bulk aerodynamic method that assumes a certain surface roughness and a friction velocity that approximates the turbulence drag on temperature and moisture mixing from the change in the average surface layer vertical wind velocity. These assumptions/approximations generally …


Incorporating Solvent Effects In Dft: Insights From Cation Exchange In Faujasites, An T. Ta, Ayoub Daouli, R. Seaton Ullberg, Eric Fonseca, Vanessa Proust, Agnès Grandjean, Richard G. Hennig, Hans Conrad Zur Loye, Michael Badawi, Simon R. Phillpot May 2024

Incorporating Solvent Effects In Dft: Insights From Cation Exchange In Faujasites, An T. Ta, Ayoub Daouli, R. Seaton Ullberg, Eric Fonseca, Vanessa Proust, Agnès Grandjean, Richard G. Hennig, Hans Conrad Zur Loye, Michael Badawi, Simon R. Phillpot

Faculty Publications

Zeolites are versatile materials renowned for their extra-framework cation exchange capabilities, with applications spanning diverse fields, including nuclear waste treatment. While detailed experimental characterization offers valuable insight, density functional theory (DFT) proves particularly adept at investigating ion exchange in zeolites, owing to its atomic and electronic resolution. However, the prevalent occurrence of zeolitic ion exchange in aqueous environments poses a challenge to conventional DFT modeling, traditionally conducted in a vacuum. This study seeks to enhance zeolite modeling by systematically evaluating predictive differences across varying degrees of aqueous solvent inclusion. Specifically focusing on monovalent cation exchange in Na-X zeolites, we explore …


Employing Digital Pcr For Enhanced Detection Of Perinatal Toxoplasma Gondii Infection: A Cross-Sectional Surveillance And Maternalinfant Outcomes Study In El Salvador, Mary K. Lynn, Marvin Stanley Rodriguez Aquino, Pamela Michelle Cornejo Rivas, Xiomara Miranda, David F. Torres-Romero, Hanson Cowan, Madeleine M. Meyer, Willber D. Castro-Godoy, Mufaro Kanyangarara Ph.D., Stella C.W. Self Ph.D., Ms, Berry A. Campbell, Melissa S. Nolan Ph.D., Mph May 2024

Employing Digital Pcr For Enhanced Detection Of Perinatal Toxoplasma Gondii Infection: A Cross-Sectional Surveillance And Maternalinfant Outcomes Study In El Salvador, Mary K. Lynn, Marvin Stanley Rodriguez Aquino, Pamela Michelle Cornejo Rivas, Xiomara Miranda, David F. Torres-Romero, Hanson Cowan, Madeleine M. Meyer, Willber D. Castro-Godoy, Mufaro Kanyangarara Ph.D., Stella C.W. Self Ph.D., Ms, Berry A. Campbell, Melissa S. Nolan Ph.D., Mph

Faculty Publications

Toxoplasma gondii is a parasitic infection that can be transmitted in utero, resulting in fetal chorioretinitis and other long-term neurological outcomes. If diagnosed early, pregnancysafe chemotherapeutics can prevent vertical transmission. Unfortunately, diagnosis of acute, primary infection among pregnant women remains neglected, particularly in low-andmiddle-income countries. Clinically actionable diagnosis is complex due to the commonality of infection during childhood and early adulthood which spawn long-last antibody titers and historically unreliable direct molecular diagnostics. The current study employed a cross-sectional T. gondii perinatal surveillance study using digital PCR, a next generation molecular diagnostic platform, and a maternal-fetal outcomes survey to ascertain the …


Deterministic Global 3d Fractal Cloud Model For Synthetic Scene Generation, Aaron M. Schinder, Shannon R. Young, Bryan J. Steward, Michael L. Dexter, Andrew Kondrath, Stephen Hinton, Ricardo Davila May 2024

Deterministic Global 3d Fractal Cloud Model For Synthetic Scene Generation, Aaron M. Schinder, Shannon R. Young, Bryan J. Steward, Michael L. Dexter, Andrew Kondrath, Stephen Hinton, Ricardo Davila

Faculty Publications

This paper describes the creation of a fast, deterministic, 3D fractal cloud renderer for the AFIT Sensor and Scene Emulation Tool (ASSET). The renderer generates 3D clouds by ray marching through a volume and sampling the level-set of a fractal function. The fractal function is distorted by a displacement map, which is generated using horizontal wind data from a Global Forecast System (GFS) weather file. The vertical windspeed and relative humidity are used to mask the creation of clouds to match realistic large-scale weather patterns over the Earth. Small-scale detail is provided by the fractal functions which are tuned to …


Investigating Turbulence Distribution In The Lower Atmosphere Using Time-Lapse Imagery From A Camera Bank, Benjamin C. Wilson, Santasri R. Bose-Pillai, Jack E. Mccrae, Steven T. Fiorino, Robert P. Freeman, Laura R. Slabaugh Apr 2024

Investigating Turbulence Distribution In The Lower Atmosphere Using Time-Lapse Imagery From A Camera Bank, Benjamin C. Wilson, Santasri R. Bose-Pillai, Jack E. Mccrae, Steven T. Fiorino, Robert P. Freeman, Laura R. Slabaugh

Faculty Publications

The atmosphere’s surface layer (first 50–100 m above the ground) is extremely dynamic and is influenced by surface radiative properties, roughness, and atmospheric stability. Understanding the distribution of turbulence in the surface layer is critical to many applications, such as directed energy and free space optical communications. Several measurement campaigns in the past have relied on weather balloons or sonic detection and ranging (SODAR) to measure turbulence up to the atmospheric boundary layer. However, these campaigns had limited measurements near the surface. We have developed a time-lapse imaging technique to profile atmospheric turbulence from turbulence-induced differential motion or tilts between …


Maternal Care Utilization And Provision During The Covid-19 Pandemic: Voices From Minoritized Pregnant And Postpartum Women And Maternal Care Providers In Deep South, Ran Zhang, Tiffany Byrd, Shan Qiao Ph.D., Myriam E. Torres Phd, Msph, Xiaoming Li Ph.D., Jihong Liu Sc.D. Apr 2024

Maternal Care Utilization And Provision During The Covid-19 Pandemic: Voices From Minoritized Pregnant And Postpartum Women And Maternal Care Providers In Deep South, Ran Zhang, Tiffany Byrd, Shan Qiao Ph.D., Myriam E. Torres Phd, Msph, Xiaoming Li Ph.D., Jihong Liu Sc.D.

Faculty Publications

Background

The COVID-19 pandemic has significantly affected maternal care services especially for minoritized individuals, creating challenges for both service users (i.e., African American and Hispanic pregnant/postpartum women) and maternal care providers (MCPs). Guided by a socioecological framework, this study aims to investigate the experiences of African American and Hispanic pregnant and postpartum women, as well as MCPs, in accessing and providing maternal care services during the COVID-19 pandemic in the Deep South.

Methods


We conducted semi-structured interviews with 19 African American women, 20 Hispanic women, and 9 MCPs between January and August 2022. Participants were recruited from Obstetrics and Gynecology …


Structural Homology Of Mite Profilins To Plant Profilins Is Not Indicative Of Allergic Cross-Reactivity, Andrea O'Malley, Sahana Sankaran, Avery Carriuolo, Kriti Khatri, Krzysztof Kowal, Maksymilian Chruszcz Ph.D. Apr 2024

Structural Homology Of Mite Profilins To Plant Profilins Is Not Indicative Of Allergic Cross-Reactivity, Andrea O'Malley, Sahana Sankaran, Avery Carriuolo, Kriti Khatri, Krzysztof Kowal, Maksymilian Chruszcz Ph.D.

Faculty Publications

Structural and allergenic characterization of mite profilins has not been previously pursued to a similar extent as plant profilins. Here, we describe structures of profilins originating from Tyrophagus putrescentiae (registered allergen Tyr p 36.0101) and Dermatophagoides pteronyssinus (here termed Der p profilin), which are the first structures of profilins from Arachnida. Additionally, the thermal stabilities of mite and plant profilins are compared, suggesting that the high number of cysteine residues in mite profilins may play a role in their increased stability. We also examine the cross-reactivity of plant and mite profilins as well as investigate the relevance of these profilins …


Deep Selenium Donors In Zngep2 Crystals: An Electron Paramagnetic Resonance Study Of A Nonlinear Optical Material, Timothy D. Gustafson, Larry E. Halliburton, Nancy C. Giles, Peter G. Schunemann, Kevin T. Zawilski, J. Jesenovec, Kent L. Averett, Jonathan E. Slagle [*] Apr 2024

Deep Selenium Donors In Zngep2 Crystals: An Electron Paramagnetic Resonance Study Of A Nonlinear Optical Material, Timothy D. Gustafson, Larry E. Halliburton, Nancy C. Giles, Peter G. Schunemann, Kevin T. Zawilski, J. Jesenovec, Kent L. Averett, Jonathan E. Slagle [*]

Faculty Publications

Zinc germanium diphosphide (ZnGeP2) is a ternary semiconductor best known for its nonlinear optical properties. A primary application is optical parametric oscillators operating in the mid-infrared region. Controlled donor doping provides a method to minimize the acceptor-related absorption bands that limit the output power of these devices. In the present study, a ZnGeP2 crystal is doped with selenium during growth. Selenium substitutes for phosphorus and serves as a deep donor. Significant concentrations of native defects (zinc vacancies, germanium-on-zinc antisites, and phosphorous vacancies) are also present in the crystal. Electron paramagnetic resonance (EPR) is used to establish the …


Identifying Multilevel Predictors Of Behavioral Outcomes Like Park Use: A Comparison Of Conditional And Marginal Modeling Approaches, Marilyn E. Wende, S. Morgan Hughey, Alexander C. Mclain, Shirelle Hallum, J. Aaron Hipp, Jasper Schipperijn, Ellen W. Stowe, Andrew T. Kaczynski Ph.D. Apr 2024

Identifying Multilevel Predictors Of Behavioral Outcomes Like Park Use: A Comparison Of Conditional And Marginal Modeling Approaches, Marilyn E. Wende, S. Morgan Hughey, Alexander C. Mclain, Shirelle Hallum, J. Aaron Hipp, Jasper Schipperijn, Ellen W. Stowe, Andrew T. Kaczynski Ph.D.

Faculty Publications

This study compared marginal and conditional modeling approaches for identifying individual, park and neighborhood park use predictors. Data were derived from the ParkIndex study, which occurred in 128 block groups in Brooklyn (New York), Seattle (Washington), Raleigh (North Carolina), and Greenville (South Carolina). Survey respondents (n = 320) indicated parks within one half-mile of their block group used within the past month. Parks (n = 263) were audited using the Community Park Audit Tool. Measures were collected at the individual (park visitation, physical activity, sociodemographic characteristics), park (distance, quality, size), and block group (park count, population density, age structure, racial …


Identifying A Group Of Factors Predicting Cognitive Impairment Among Older Adults, Longgang Zhao, Yuan Wang, Eric Mishio Bawa, Zichun Meng, Jingkai Wei, Sarah Newman-Norlund, Tushar Trivedi, Hatice Hasturk, Roger Newman-Norlund, Julius Fridriksson Ph.D., Anwar T. Nerchant Apr 2024

Identifying A Group Of Factors Predicting Cognitive Impairment Among Older Adults, Longgang Zhao, Yuan Wang, Eric Mishio Bawa, Zichun Meng, Jingkai Wei, Sarah Newman-Norlund, Tushar Trivedi, Hatice Hasturk, Roger Newman-Norlund, Julius Fridriksson Ph.D., Anwar T. Nerchant

Faculty Publications

Background

Cognitive impairment has multiple risk factors spanning several domains, but few studies have evaluated risk factor clusters. We aimed to identify naturally occurring clusters of risk factors of poor cognition among middle-aged and older adults and evaluate associations between measures of cognition and these risk factor clusters.

Methods

We used data from the National Health and Nutrition Examination Survey (NHANES) III (training dataset, n = 4074) and the NHANES 2011–2014 (validation dataset, n = 2510). Risk factors were selected based on the literature. We used both traditional logistic models and support vector machine methods to construct a composite score …


Broad-Spectrum Lignin-Based Adhesives Using Thiol–Silyl Ether Crosslinkers, Yishayah Bension, Siteng Zhang, Tristan Menninger, Ting Ge, Chuanbing Tang Apr 2024

Broad-Spectrum Lignin-Based Adhesives Using Thiol–Silyl Ether Crosslinkers, Yishayah Bension, Siteng Zhang, Tristan Menninger, Ting Ge, Chuanbing Tang

Faculty Publications

Lignin is a renewable feedstock that is abundant and inexpensive but still presents challenges for its valorization. In this work, we converted functionalized lignin into broad-spectrum adhesives using thiol–silyl ether crosslinkers. The curing behavior of adhesives was investigated via rheology of their resin forms. These materials exhibit good adhesion on diverse substrates, including wood, glass, steel, aluminium, carbon fiber, and different plastics, with the most adhesion strength in the range of 1–3 MPa. These adhesives were also explored for applications, ranging from wet conditions to different mechanically responsive materials. The mechanism of adhesion was further examined to understand the bonding …


Associations Between Sleep Duration, Sleep Disturbance And Cardiovascular Disease Biomarkers Among Adults In The United States, Prince Nii Ossah Addo, Paddington T. Mundagowa, Longgang Zhao, Mufaro Kanyangarara, Monique J. Brown Ph.D., Mph, Jihong Liu Sc.D. Apr 2024

Associations Between Sleep Duration, Sleep Disturbance And Cardiovascular Disease Biomarkers Among Adults In The United States, Prince Nii Ossah Addo, Paddington T. Mundagowa, Longgang Zhao, Mufaro Kanyangarara, Monique J. Brown Ph.D., Mph, Jihong Liu Sc.D.

Faculty Publications

Background

Sleep problems are associated with abnormal cardiovascular biomarkers and an increased risk of cardiovascular diseases (CVDs). However, studies investigating associations between sleep problems and CVD biomarkers have reported conflicting findings. This study examined the associations between sleep problems and CVD biomarkers in the United States.

Methods

Data were from the National Health and Nutrition Examination Survey (NHANES) (2007–2018) and analyses were restricted to adults ≥ 20 years (n = 23,749). CVD biomarkers [C-reactive Protein (CRP), low-density lipoproteins, high-density lipoproteins (HDL), triglycerides, insulin, glycosylated hemoglobin (HbA1c), and fasting blood glucose] were categorized as abnormal or normal using standardized cut-off …


Exploring Quaternion Neural Network Loss Surfaces, Jeremiah Bill, Bruce A. Cox Apr 2024

Exploring Quaternion Neural Network Loss Surfaces, Jeremiah Bill, Bruce A. Cox

Faculty Publications

This paper explores the superior performance of quaternion multi-layer perceptron (QMLP) neural networks over real-valued multi-layer perceptron (MLP) neural networks, a phenomenon that has been empirically observed but not thoroughly investigated. The study utilizes loss surface visualization and projection techniques to examine quaternion-based optimization loss surfaces for the first time. The primary contribution of this research is the statistical evidence that QMLP models yield smoother loss surfaces than real-valued neural networks, which are measured and compared using a robust quantitative measure of loss surface “goodness” based on estimates of surface curvature. Extensive computational testing validates the effectiveness of these surface …


Creation Of Bound Half-Fermion Pairs By Solitons, Sapan Karki, Brett Altschul Apr 2024

Creation Of Bound Half-Fermion Pairs By Solitons, Sapan Karki, Brett Altschul

Faculty Publications

In the presence of topologically nontrivial bosonic field configurations, the fermion number operator may take on fractional eigenvalues, because of the existence of zero-energy fermion modes. The simplest examples of this occur in 1+1 dimensions, with zero modes attached to kink-type solitons. In the presence of a kink-antikink pair, the two associated zero modes bifurcate into positive and negative energy levels with energies ±ge-gΔ, in terms of the Yukawa coupling g≪1 and the distance Δ between the kink and antikink centers. When the kink and antikink are moving, it seems that there could be Landau–Zener-like transitions between these …


Pulsed-Power Neutron Production With Deuterated Polymer Accelerator Targets, Anthony O. Hagey, Juan J. Manfredi, Whitman T. Dailey, S. L. Jackson, E. R. Kaiser, J. W. Schumer Apr 2024

Pulsed-Power Neutron Production With Deuterated Polymer Accelerator Targets, Anthony O. Hagey, Juan J. Manfredi, Whitman T. Dailey, S. L. Jackson, E. R. Kaiser, J. W. Schumer

Faculty Publications

This document presents an investigation of the effect of deuterated accelerator targets on the neutron fluence from a local mass injection dense plasma focus (LMIDPF) driven by the United States Naval Research Laboratory's (NRL) Hawk pulsed-power generator. Deuterated targets were made using two methods: a well-established thin-film casting technique for flat targets and a more novel additive manufacturing technique that allowed targets to be three-dimensional (3D) printed in both flat and conical geometries. These targets were then tested during neutron-producing experiments conducted using Hawk, and theneutron fluences measured for the various target types were compared. Additive manufacturing was used as …


Comparison Of Raw Accelerometry Data From Actigraph, Apple Watch, Garmin, And Fitbit Using A Mechanical Shaker Table, James W. White Iii, Olivia L. Finnegan, Nick Tindall, Srihari Nelakuditi, David E. Brown Iii, Russell R. Pate Ph.D., Gregory J. Welk, Massimiliano De Zambotti, Rahul Ghosal, Yuan Wang, Sarah Burkart, Elizabeth L. Adams, Mvs Chandrashekhar, Bridget Armstrong, Michael W. Beets, Robert Weaver Med, Phd Mar 2024

Comparison Of Raw Accelerometry Data From Actigraph, Apple Watch, Garmin, And Fitbit Using A Mechanical Shaker Table, James W. White Iii, Olivia L. Finnegan, Nick Tindall, Srihari Nelakuditi, David E. Brown Iii, Russell R. Pate Ph.D., Gregory J. Welk, Massimiliano De Zambotti, Rahul Ghosal, Yuan Wang, Sarah Burkart, Elizabeth L. Adams, Mvs Chandrashekhar, Bridget Armstrong, Michael W. Beets, Robert Weaver Med, Phd

Faculty Publications

The purpose of this study was to evaluate the reliability and validity of the raw accelerometry output from research-grade and consumer wearable devices compared to accelerations produced by a mechanical shaker table. Raw accelerometry data from a total of 40 devices (i.e., n = 10 ActiGraph wGT3X-BT, n = 10 Apple Watch Series 7, n = 10 Garmin Vivoactive 4S, and n = 10 Fitbit Sense) were compared to reference accelerations produced by an orbital shaker table at speeds ranging from 0.6 Hz (4.4 milligravity-mg) to 3.2 Hz (124.7mg). Two-way random effects absolute intraclass correlation coefficients (ICC) tested inter-device reliability. …


Effect Of Fabrication Parameters On The Ferroelectricity Of Hafnium Zirconium Oxide Films: A Statistical Study, Guillermo A. Salcedo, Ahmad E. Islam, Elizabeth Reichley, Michael Dietz, Christine M. Schubert Kabban, Kevin D. Leedy, Tyson C. Back, Weison Wang, Andrew Green, Timothy S. Wolfe, James M. Sattler Mar 2024

Effect Of Fabrication Parameters On The Ferroelectricity Of Hafnium Zirconium Oxide Films: A Statistical Study, Guillermo A. Salcedo, Ahmad E. Islam, Elizabeth Reichley, Michael Dietz, Christine M. Schubert Kabban, Kevin D. Leedy, Tyson C. Back, Weison Wang, Andrew Green, Timothy S. Wolfe, James M. Sattler

Faculty Publications

Ferroelectricity in hafnium zirconium oxide (Hf1−xZrxO2) and the factors that impact it have been a popular research topic since its discovery in 2011. Although the general trends are known, the interactions between fabrication parameters and their effect on the ferroelectricity of Hf1−xZrxO2 require further investigation. In this paper, we present a statistical study and a model that relates Zr concentration (x), film thickness (tf), and annealing temperature (Ta) with the remanent polarization (Pr) in tungsten (W)-capped Hf1−xZrxO2. …


Size Limits And Fission Channels Of Doubly Charged Noble Gas Clusters, Ianessa Stromberg, Stefan Bergmeister, Lisa Ganner, Fabio Zappa, Paul Scheier, Olof Echt, Elisabeth Gruber Mar 2024

Size Limits And Fission Channels Of Doubly Charged Noble Gas Clusters, Ianessa Stromberg, Stefan Bergmeister, Lisa Ganner, Fabio Zappa, Paul Scheier, Olof Echt, Elisabeth Gruber

Faculty Publications

Small, highly charged liquid droplets are unstable with respect to spontaneous charge separation when their size drops below the Rayleigh limit or, in other words, their fissility parameter X exceeds the value 1. The absence of small doubly charged atomic cluster ions in mass spectra below an element-specific appearance size na has sometimes been attributed to the onset of barrierless fission at X = 1. However, more realistic models suggest that na marks the size below which the rate of fission surpasses that of competing dissociative channels, and the Rayleigh limit of doubly charged van der Waals clusters …


Scriptblock Smuggling: Uncovering Stealthy Evasion Techniques In Powershell And .Net Environments, Anthony J. Rose, Scott R. Graham, Christine M. Schubert, Jacob Krasnov, Wayne C. Henry Mar 2024

Scriptblock Smuggling: Uncovering Stealthy Evasion Techniques In Powershell And .Net Environments, Anthony J. Rose, Scott R. Graham, Christine M. Schubert, Jacob Krasnov, Wayne C. Henry

Faculty Publications

The Antimalware Scan Interface (AMSI) plays a crucial role in detecting malware within Windows operating systems. This paper presents ScriptBlock Smuggling, a novel evasion and log spoofing technique exploiting PowerShell and .NET environments to circumvent the AMSI. By focusing on the manipulation of ScriptBlocks within the Abstract Syntax Tree (AST), this method creates dual AST representations, one for compiler execution and another for antivirus and log analysis, enabling the evasion of AMSI detection and challenging traditional memory patching bypass methods. This research provides a detailed analysis of PowerShell’s ScriptBlock creation and its inherent security features and pinpoints critical limitations in …


Data Supporting Research On Personalized Learning Paths, Sean Mochocki, Mark Reith Mar 2024

Data Supporting Research On Personalized Learning Paths, Sean Mochocki, Mark Reith

Faculty Publications

Personalized Learning Paths (PLPs) are a key application of Artificial Intelligence in E-Learning. In contrast to regular Learning Paths, they return a unique sequence of learning materials identified as meeting the individual needs of the students. In the literature, PLPs are often created from knowledge graphs, which assist with ordering topics and their associated learning materials. Knowledge graphs are typically directed and acyclic, to capture prerequisite relationships between topics, though they can also have bidirectional edges when these prerequisite relationships are not necessary. This data package provides a primarily un-directed knowledge graph, with associated repository of open-source learning materials that …