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Illustrative Application Of The Nth-Order Comprehensive Adjoint Sensitivity Analysis Methodology For Nonlinear Systems To The Nordheim–Fuchs Reactor Dynamics/Safety Model, Dan Gabriel Cacuci Jun 2022

Illustrative Application Of The Nth-Order Comprehensive Adjoint Sensitivity Analysis Methodology For Nonlinear Systems To The Nordheim–Fuchs Reactor Dynamics/Safety Model, Dan Gabriel Cacuci

Faculty Publications

The application of the recently developed “nth-order comprehensive sensitivity analysis methodology for nonlinear systems” (abbreviated as “nth-CASAM-N”) has been previously illustrated on paradigm nonlinear space-dependent problems. To complement these illustrative applications, this work illustrates the application of the nth-CASAM-N to a paradigm nonlinear time-dependent model chosen from the field of reactor dynamics/safety, namely the well-known Nordheim–Fuchs model. This phenomenological model describes a short-time self-limiting power transient in a nuclear reactor system having a negative temperature coefficient in which a large amount of reactivity is suddenly inserted, either intentionally or by accident. This model is sufficiently complex to demonstrate all the …

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The NTh-Order Comprehensive Adjoint Sensitivity Analysis Methodology For Nonlinear Systems (Nth-Casam-N): Mathematical Framework, Dan Gabriel Cacuci Jun 2022

The NTh-Order Comprehensive Adjoint Sensitivity Analysis Methodology For Nonlinear Systems (Nth-Casam-N): Mathematical Framework, Dan Gabriel Cacuci

Faculty Publications

This work presents the nth-Order Comprehensive Adjoint Sensitivity Analysis Methodology for Nonlinear Systems (nth-CASAM-N), which enables the most efficient computation of exactly determined expressions of arbitrarily high-order sensitivities of generic nonlinear system responses with respect to model parameters, uncertain boundaries, and internal interfaces in the model’s phase space. The mathematical framework underlying the nth-CASAM-N is proven to be correct by using mathematical induction. The nth-CASAM-N is formulated in linearly increasing higher-dimensional Hilbert spaces—as opposed to exponentially increasing parameter-dimensional spaces—thus overcoming the curse of dimensionality in sensitivity analysis of nonlinear systems.

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Microbiome Assembly In Thawing Permafrost And Its Feedbacks To Climate, Jessica G. Ernakovich, Robyn A. Barbato, Virginia I. Ritch, Christina Schadel, Rebecca E. Hewitt, Stacey J. Doherty, Emily D. Whalen, Benjamin Abbott, Jiri Barta, Christina Biasi, Chris L. Chabot, Jenni Hultman, Christian Knoblauch, Maggie C. Y. Lau Vetter, Mary-Cathrine Leewis, Susanne Liebner, Rachel Mackelprang, Tullis C. Onstott, Andreas Richter, Ursel M. E. Schutte, Henri M. P. Siljanen, Neslihan Tas, Ina Timling, Tatiana A. Vishnivetskaya, Mark P. Waldrop, Matthias Winkel Jun 2022

Microbiome Assembly In Thawing Permafrost And Its Feedbacks To Climate, Jessica G. Ernakovich, Robyn A. Barbato, Virginia I. Ritch, Christina Schadel, Rebecca E. Hewitt, Stacey J. Doherty, Emily D. Whalen, Benjamin Abbott, Jiri Barta, Christina Biasi, Chris L. Chabot, Jenni Hultman, Christian Knoblauch, Maggie C. Y. Lau Vetter, Mary-Cathrine Leewis, Susanne Liebner, Rachel Mackelprang, Tullis C. Onstott, Andreas Richter, Ursel M. E. Schutte, Henri M. P. Siljanen, Neslihan Tas, Ina Timling, Tatiana A. Vishnivetskaya, Mark P. Waldrop, Matthias Winkel

Faculty Publications

The physical and chemical changes that accompany permafrost thaw directly influence the microbial communities that mediate the decomposition of formerly frozen organic matter, leading to uncertainty in permafrost–climate feedbacks. Although changes to microbial metabolism and community structure are documented following thaw, the generality of post-thaw assembly patterns across permafrost soils of the world remains uncertain, limiting our ability to predict biogeochemistry and microbial community responses to climate change. Based on our review of the Arctic microbiome, permafrost microbiology, and community ecology, we propose that Assembly Theory provides a framework to better understand thaw-mediated microbiome changes and the implications for community …

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Ocean-Atmosphere Variability In The Northwest Atlantic Ocean During Active Marine Heatwave Years, Lydia D. Sims, Bulusu Subrahmanyam, Corinne B. Trott Jun 2022

Ocean-Atmosphere Variability In The Northwest Atlantic Ocean During Active Marine Heatwave Years, Lydia D. Sims, Bulusu Subrahmanyam, Corinne B. Trott

Faculty Publications

The Northwest (NW) Atlantic has experienced extreme ecological impacts from Marine Heatwaves (MHWs) within the past decade. This paper focuses on four MHW active years (2012, 2016, 2017, and 2020) and the relationship between Sea Surface Temperature anomalies (SSTA), Sea Surface Salinity anomalies (SSSA), North Atlantic Oscillation (NAO), Geopotential Height anomalies (ZA), and anomalous Jet Stream positions (JSPA). Multichannel singular spectrum analysis (MSSA) reveals the strongest temporal covariances between SSSA and SSTA, and JSPA and SSTA for all years, particularly for 2020 (SSSA–SSTA: 50%, JSPA–SSTA: 51%) indicating that this active MHW year was more atmospherically driven, followed by 2012, which …

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Luminescence And Scintillation In The Niobium Doped Oxyfluoride Rb4Ge5O9F6:Nb, Darren Carone, Vladislav V. Klepov, Scott T. Misture, Joseph C. Schaeperkoetter, Luiz G. Jacobsohn, Mina Aziziha, Juliano Schorne-Pinto, Stuart A. J. Thomson, Adrian T. Hines, Theodore M. Besmann, Hans Conrad Zur Loye Jun 2022

Luminescence And Scintillation In The Niobium Doped Oxyfluoride Rb4Ge5O9F6:Nb, Darren Carone, Vladislav V. Klepov, Scott T. Misture, Joseph C. Schaeperkoetter, Luiz G. Jacobsohn, Mina Aziziha, Juliano Schorne-Pinto, Stuart A. J. Thomson, Adrian T. Hines, Theodore M. Besmann, Hans Conrad Zur Loye

Faculty Publications

A new niobium-doped inorganic scintillating oxyfluoride, Rb4Ge5O9F6:Nb, was synthesized in single crystal form by high-temperature flux growth. The host structure, Rb4Ge5O9F6, crystallizes in the orthorhombic space group Pbcn with lattice parameters a = 6.98430(10) Å, b = 11.7265(2) Å, and c = 19.2732(3) Å, consisting of germanium oxyfluoride layers made up of Ge3O9 units connected by GeO3F3 octahedra. In its pure form, Rb4Ge5O9F6 shows neither luminescence nor scintillation but when doped …

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The Inequalities Of Innovation, Colleen Chien Jun 2022

The Inequalities Of Innovation, Colleen Chien

Faculty Publications

Over the last few decades, the United States has become more innovative, but the gains have been distributed unequally. In 2020, over 50% of new U.S. patents went to the top 1% of patentees, and more than 50% of all patents of U.S. origin were generated by just five states, all coastal. Less than 13% of inventors were women. The economic, geographic, and demographic concentration of innovation highlight how the intersections between two traditionally discrete topics—innovation and inequality—have become increasingly relevant. But rather than any single inequality, this Article argues, multiple inequalities—of income, opportunity, and access—have relevance to innovation. Examining …

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Machine Learning Prediction Of Glass Transition Temperature Of Conjugated Polymers From Chemical Structure, Amirhadi Alesadi, Zhiqiang Cao, Zhaofan Li, Song Zhang, Haoyu Zhao, Xiaodan Gu, Wenjie Xia Jun 2022

Machine Learning Prediction Of Glass Transition Temperature Of Conjugated Polymers From Chemical Structure, Amirhadi Alesadi, Zhiqiang Cao, Zhaofan Li, Song Zhang, Haoyu Zhao, Xiaodan Gu, Wenjie Xia

Faculty Publications

Predicting the glass transition temperature (Tg) is of critical importance as it governs the thermomechanical performance of conjugated polymers (CPs). Here, we report a predictive modeling framework to predict Tg of CPs through the integration of machine learning (ML), molecular dynamics (MD) simulations, and experiments. With 154 Tg data collected, an ML model is developed by taking simplified “geometry” of six chemical building blocks as molecular features, where side-chain fraction, isolated rings, fused rings, and bridged rings features are identified as the dominant ones for Tg. MD simulations further unravel the fundamental roles …

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A Westerly Wind Dominated Puna Plateau During Deposition Of Upper Pleistocene Loessic Sediments In The Subtropical Andes, South America, Alex Pullen, David L. Barbeau Jr, Andrew Leier, Madison Ward, Austin Bruner, Mary Kate Fidler Jun 2022

A Westerly Wind Dominated Puna Plateau During Deposition Of Upper Pleistocene Loessic Sediments In The Subtropical Andes, South America, Alex Pullen, David L. Barbeau Jr, Andrew Leier, Madison Ward, Austin Bruner, Mary Kate Fidler

Faculty Publications

The Tafí del Valle depression (~27° S) in the eastern Andes of Argentina provides a record of late Pleistocene dust deposition in the subtropics of South America. We present large-n U-Pb geochronology data for detrital zircons from upper Pleistocene loess-paleosol deposits. When compared to regional data, the age spectra from the Tafí del Valle samples are most like the southern Puna Plateau, supporting derivation largely from the west and northwest. This runs counter to hypotheses suggesting these loessic sediments were derived from the low elevation plains to the east or extra-Andean Patagonia. Mapping of linear wind erosion features on …

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Factors Associated With Covid-19 Vaccine Intentions Among South Carolina Residents, Mufaro Kanyangarara, Lauren Mcabee, Virginie G. Daguise, Melissa Nolan Ph.D., Mph Jun 2022

Factors Associated With Covid-19 Vaccine Intentions Among South Carolina Residents, Mufaro Kanyangarara, Lauren Mcabee, Virginie G. Daguise, Melissa Nolan Ph.D., Mph

Faculty Publications

Despite evidence of vaccine safety and efficacy, vaccine hesitancy remains a major global health threat. The COVID-19 vaccine has presented unique vaccine hesitancy concerns compared to parental vaccine hesitancy towards childhood vaccines. South Carolina (SC) is home to a largely conservative population and historically has some of the lowest vaccination coverage rates in the United States of America. The goal of the current study was to identify factors associated with COVID-19 vaccine intentions among SC residents. From November 2020 to September 2021, 300,000 invitations to participate in community testing and complete an online survey were mailed to randomly selected SC …

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Expected Sensitivity To 128Te Neutrinoless Double Beta Decay With The Cuore Teo2 Cryogenic Bolometers, V. Dompé, D. Q. Adams, C. Alduino, K. Alfonso, Frank Avignone Iii Jun 2022

Expected Sensitivity To 128Te Neutrinoless Double Beta Decay With The Cuore Teo2 Cryogenic Bolometers, V. Dompé, D. Q. Adams, C. Alduino, K. Alfonso, Frank Avignone Iii

Faculty Publications

The CUORE experiment is a ton-scale array of TeO2 cryogenic bolometers located at the underground Laboratori Nazionali del Gran Sasso of Istituto Nazionale di Fisica Nucleare (INFN), in Italy. The CUORE detector consists of 988 crystals operated as source and detector at a base temperature of ∼ 10 mK. Such cryogenic temperature is reached and maintained by means of a custom built cryogen-free dilution cryostat, designed with the aim of minimizing the vibrational noise and the environmental radioactivity. The primary goal of CUORE is the search for neutrinoless double beta decay of 130Te, but thanks to its …

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Maternal Lineage And Habitat Use Patterns Explain Variation In The Fecundity Of A Critically Endangered Baleen Whale, Ana L. Bishop, Leah M. Crowe, Philip K. Hamilton, Erin L. Meyer-Gutbrod Jun 2022

Maternal Lineage And Habitat Use Patterns Explain Variation In The Fecundity Of A Critically Endangered Baleen Whale, Ana L. Bishop, Leah M. Crowe, Philip K. Hamilton, Erin L. Meyer-Gutbrod

Faculty Publications

The critically endangered North Atlantic right whale population (Eubalaena glacialis) has experienced multiple periods of decreased reproduction within its observable history, which have played a role in the overall decline of the species. In addition to this synchronized variation in reproduction across the population, there exists considerable individual variation in fecundity. To determine the impacts of family history and habitat use behavior on these individual variations in fecundity, photo identification data collected during four decades of visual monitoring were used to create a calving index for sexually mature females that could be used to evaluate matrilineal influence on …

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Historic Wooden Shipwrecks Influence Dispersal Of Deep-Sea Biofilms, Rachel D. Moseley, Justyna J. Hampel, Rachel L. Mugge, Leila J. Hamdan Jun 2022

Historic Wooden Shipwrecks Influence Dispersal Of Deep-Sea Biofilms, Rachel D. Moseley, Justyna J. Hampel, Rachel L. Mugge, Leila J. Hamdan

Faculty Publications

Wood arrives on the seabed from natural and anthropogenic sources (e.g., wood falls and wooden shipwrecks, respectively) and creates seafloor habitats for macro-, meio- and microbiota. The way these habitats shape microbial communities and their biogeographic patterns in the deep sea requires study. The objective of this work was to investigate how historic wooden-hulled shipwrecks impact the dispersal of wood-colonizing microbial biofilms. The study addressed how proximity to wooden shipwrecks shapes diversity, richness, and community composition in the surrounding environment. Study sites included two historic shipwrecks in the northern Gulf of Mexico identified as wooden-hulled sailing vessels dating to the …

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Improving On Atmospheric Turbulence Profiles Derived From Dual Beacon Hartmann Turbulence Sensor Measurements, Alexander S. Boeckenstedt, Jack E. Mccrae, Santasri Bose-Pillai, Benjamin Wilson Jun 2022

Improving On Atmospheric Turbulence Profiles Derived From Dual Beacon Hartmann Turbulence Sensor Measurements, Alexander S. Boeckenstedt, Jack E. Mccrae, Santasri Bose-Pillai, Benjamin Wilson

Faculty Publications

Atmospheric turbulence is an inevitable source of wavefront distortion in all fields of long range laser propagation and sensing. However, the distorting effects of turbulence can be corrected using wavefront sensors contained in adaptive optics systems. Such systems also provide deeper insight into surface layer turbulence, which is not well understood. A unique method of profile generation by a dual source Hartmann Turbulence Sensor (HTS) technique is introduced here. Measurements of optical turbulence along a horizontal path were taken to create C2n profiles. Two helium-neon laser beams were directed over an inhomogeneous horizontal path and captured by the HTS. The …

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A Preliminary Study Of Proinflammatory Cytokines And Depression Following West Nile Virus Infection, Allison Lino, Timothy A. Erickson, Melissa Nolan Ph.D., Mph, Kristy O. Murray, Shannon E. Ronca Jun 2022

A Preliminary Study Of Proinflammatory Cytokines And Depression Following West Nile Virus Infection, Allison Lino, Timothy A. Erickson, Melissa Nolan Ph.D., Mph, Kristy O. Murray, Shannon E. Ronca

Faculty Publications

West Nile virus (WNV) is a neurotropic flavivirus that can cause acute febrile illness leading to neuroinvasive disease. Depression is a well-described outcome following infection, but the underlying pathogenic mechanisms are unknown. Proinflammatory cytokines play important roles in WNV infection, but their role in depression post-WNV remains unstudied. This research aimed to retrospectively evaluate associations between proinflammatory cytokines and new onset depression in a WNV cohort. Participants with asymptomatic WNV infection were significantly less likely to report new onset depression when compared to those with symptomatic disease. Participants with encephalitis and obesity were significantly more likely to report new onset …

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Climate Change Reshuffles Northern Species Within Their Niches, Laura H. Antao, Benjamin Weigel, Giovanni Strona, Maria Hallfors, Elina Kaarlejarvi, Tad Dallas, Oystein H. Opedal, Janne Heliola, Heikki Henttonen, Otso Huitu, Erkki Korpimaki, Mikko Kuussaari, Aleksi Lehikoinen, Reima Leinonen, Andreas Lindén, Paivi Merila, Hannu Pietianinen, Juha Poyry, Maija Salemaa, Tiina Tonteri, Kristiina Vuorio, Otso Ovaskainen, Marjo Saastamoinen, Jarno Vanhatalo, Tomas Roslin, Anna-Liisa Laine Jun 2022

Climate Change Reshuffles Northern Species Within Their Niches, Laura H. Antao, Benjamin Weigel, Giovanni Strona, Maria Hallfors, Elina Kaarlejarvi, Tad Dallas, Oystein H. Opedal, Janne Heliola, Heikki Henttonen, Otso Huitu, Erkki Korpimaki, Mikko Kuussaari, Aleksi Lehikoinen, Reima Leinonen, Andreas Lindén, Paivi Merila, Hannu Pietianinen, Juha Poyry, Maija Salemaa, Tiina Tonteri, Kristiina Vuorio, Otso Ovaskainen, Marjo Saastamoinen, Jarno Vanhatalo, Tomas Roslin, Anna-Liisa Laine

Faculty Publications

Climate change is a pervasive threat to biodiversity. While range shifts are a known consequence of climate warming contributing to regional community change, less is known about how species’ positions shift within their climatic niches. Furthermore, whether the relative importance of different climatic variables prompting such shifts varies with changing climate remains unclear. Here we analysed four decades of data for 1,478 species of birds, mammals, butterflies, moths, plants and phytoplankton along a 1,200 km high latitudinal gradient. The relative importance of climatic drivers varied non-uniformly with progressing climate change. While species turnover among decades was limited, the relative position …

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Computational Methods To Simulate Molten Salt Thermophysical Properties, Talmage Porter, Michael M. Vaka, Parker Steenblik, Dennis Della Corte Jun 2022

Computational Methods To Simulate Molten Salt Thermophysical Properties, Talmage Porter, Michael M. Vaka, Parker Steenblik, Dennis Della Corte

Faculty Publications

Molten salts are important thermal conductors used in molten salt reactors and solar applications. To use molten salts safely, accurate knowledge of their thermophysical properties is necessary. However, it is experimentally challenging to measure these properties and a comprehensive evaluation of the full chemical space is unfeasible. Computational methods provide an alternative route to access these properties. Here, we summarize the developments in methods over the last 70 years and cluster them into three relevant eras. We review the main advances and limitations of each era and conclude with an optimistic perspective for the next decade, which will likely be …

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Victims As Instruments, Rachel J. Wechsler Jun 2022

Victims As Instruments, Rachel J. Wechsler

Faculty Publications

Crime victims are often instrumentalized within the criminal legal process in furtherance of state prosecutorial interests. This is a particularly salient issue concerning victims of gender-based violence (GBV) because victim testimony is typically considered essential for successful prosecution of these types of crimes. Since the U.S. Supreme Court's 2004 decision in Crawford v. Washington, courts require declarants to be available for cross-examination on "testimonial" hearsay evidence. Consequently, criminal legal actors are further incentivized to employ highly coercive practices aimed at securing GBV victims' participation in the criminal legal process as evidentiary tools. These practices include arresting and incarcerating victims through …

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Influence Of Weather On Gobbling Activity Of Male Wild Turkeys, Patrick H. Wightman, James A. Martin, John C. Kilgo, Emily Rushton, Bret A. Collier, Michael J. Chamberlain Jun 2022

Influence Of Weather On Gobbling Activity Of Male Wild Turkeys, Patrick H. Wightman, James A. Martin, John C. Kilgo, Emily Rushton, Bret A. Collier, Michael J. Chamberlain

Faculty Publications

Gobbling activity of Eastern wild turkeys (Meleagris gallopavo silvestris; hereafter, turkeys) has been widely studied, focusing on drivers of daily variation. Weather variables are widely believed to influence gobbling activity, but results across studies are contradictory and often equivocal, leading to uncertainty in the relative contribution of weather variables to daily fluctuations in gobbling activity. Previous works relied on road-based auditory surveys to collect gobbling data, which limits data consistency, duration, and quantity due to logistical difficulties associated with human observers and restricted sampling frames. Development of new methods using autonomous recording units (ARUs) allows researchers to collect continuous data …

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Feedback Stabilization And Robustness Analysis Using Bounds On Fundamental Matrices, Frederic Mazenc, Michael Malisoff Jun 2022

Feedback Stabilization And Robustness Analysis Using Bounds On Fundamental Matrices, Frederic Mazenc, Michael Malisoff

Faculty Publications

We prove a new robust stabilization theorem for time-varying systems that have sampled measurements and time-varying disturbances, and we provide new observer designs, using novel bounds for fundamental matrices for systems with disturbances. Our main tools use properties of Metzler matrices and positive systems.

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In Search Of Short Gamma-Ray Burst Optical Counterparts With The Zwicky Transient Facility, Tomás Ahumada, Shreya Anand, Michael W. Coughlin, Igor Andreoni, Erik C. Kool, Harsh Kumar, Simeon Reusch, Ana Sagués-Carracedo, Robert Stein, S. Bradley Cenko, Mansi M. Kasliwal, Leo P. Singer, Rachel Dunwoody, Joseph Mangan, Varun Bhalerao, Mattia Bulla, Eric Burns, Matthew J. Graham, David L. Kaplan, Daniel Perley, Mouza Almualla, Joshua S. Bloom, Virginia Cunningham, Kishalay De, Pradip Gatkine, Anna Y.Q. Ho, Viraj Karambelkar, Albert K.H. Kong, Yuhan Yao, G. C. Anupama, Sudhanshu Barway, Shaon Ghosh, Ryosuke Itoh Jun 2022

In Search Of Short Gamma-Ray Burst Optical Counterparts With The Zwicky Transient Facility, Tomás Ahumada, Shreya Anand, Michael W. Coughlin, Igor Andreoni, Erik C. Kool, Harsh Kumar, Simeon Reusch, Ana Sagués-Carracedo, Robert Stein, S. Bradley Cenko, Mansi M. Kasliwal, Leo P. Singer, Rachel Dunwoody, Joseph Mangan, Varun Bhalerao, Mattia Bulla, Eric Burns, Matthew J. Graham, David L. Kaplan, Daniel Perley, Mouza Almualla, Joshua S. Bloom, Virginia Cunningham, Kishalay De, Pradip Gatkine, Anna Y.Q. Ho, Viraj Karambelkar, Albert K.H. Kong, Yuhan Yao, G. C. Anupama, Sudhanshu Barway, Shaon Ghosh, Ryosuke Itoh

Faculty Publications

The Fermi Gamma-ray Burst Monitor (GBM) triggers on-board in response to ∼40 short gamma-ray bursts (SGRBs) per year; however, their large localization regions have made the search for optical counterparts a challenging endeavour. We have developed and executed an extensive program with the wide field of view of the Zwicky Transient Facility (ZTF) camera, mounted on the Palomar 48 inch Oschin telescope (P48), to perform target-of-opportunity (ToO) observations on 10 Fermi-GBM SGRBs during 2018 and 2020-2021. Bridging the large sky areas with small field-of-view optical telescopes in order to track the evolution of potential candidates, we look for the elusive …

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Highly Swellable Hydrogels Prepared From Extensively Oxidized Lignin, Jihyeon Hwang, Daniella V. Martinez, Estevan J. Martinez, Gift Metavarayuth, Dustin Goodlett, Qi Wang, Mitra Ganewatta, Michael S. Kent, Chuanbing Tang Jun 2022

Highly Swellable Hydrogels Prepared From Extensively Oxidized Lignin, Jihyeon Hwang, Daniella V. Martinez, Estevan J. Martinez, Gift Metavarayuth, Dustin Goodlett, Qi Wang, Mitra Ganewatta, Michael S. Kent, Chuanbing Tang

Faculty Publications

Biopolymers such as lignin are gaining renewed appeal due to the need for sustainable materials. Herein, we used chelator-mediated Fenton (CMF) chemistry to oxidize Kraft lignin to develop sustainable super absorbent materials. The CMF chemistry adds oxygen, opens aromatic rings and increases COOH content, producing hydrophilic lignin without depolymerization. UV absorption, molecular weight, elemental analysis, and titration were used to study the chemical compositions of CMF-processed lignin. Then the chemically modified hydrophilic lignin was used to produce lignin-based hydrogels utilizing an aqueous polymerization and cross-linking reaction that enabled tunable properties. The resulting lignin hydrogels absorbed water up to 96% and …

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Understanding Rapid Intercalation Materials One Parameter At A Time, Wessel Van Den Bergh, Morgan Stefik Jun 2022

Understanding Rapid Intercalation Materials One Parameter At A Time, Wessel Van Den Bergh, Morgan Stefik

Faculty Publications

Demand for fast, energy-dense storage drives the research into nanoscale intercalation materials. Nanomaterials accelerate kinetics and can modify reaction path thermodynamics, intercalant solubility, and reversibility. The discovery of intercalation pseudocapacitance has opened questions about their fundamental operating principles. For example, are their capacitor-like current responses caused by storing energy in special near-surface regions or rather is this response due to normal intercalation limited by a slower faradaic surface-reaction? This review highlights emerging methods combining tailored nanomaterials with the process of elimination to disambiguate cause-and-effect at the nanoscale. This method is applied to multiple intercalation pseudocapacitive materials showing that the timescales …

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The Price Of Decentralization In Cooperative Coverage Problems With Energy-Constrained Agents, Xiangyu Meng, Christos G. Cassandras, Xinmiao Sun, Kaiyuan Xu Jun 2022

The Price Of Decentralization In Cooperative Coverage Problems With Energy-Constrained Agents, Xiangyu Meng, Christos G. Cassandras, Xinmiao Sun, Kaiyuan Xu

Faculty Publications

A multiagent coverage problem is considered with energy-constrained agents, where a charging station is used to replenish an agent's energy as it becomes depleted while performing the coverage task. The objective of this article is to compare the coverage performance between centralized and decentralized approaches. To this end, a centralized coverage control method is developed to switch agents between an optimal coverage formation and an optimal charging formation. We design a controller for agent trajectories that include dwell times at the optimal coverage locations, and charging times at the charging station to maximize a coverage metric over a finite time …

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New Efficient Approach To Solve Big Data Systems Using Parallel Gauss–Seidel Algorithms, Shih Yu Chang, Hsiao Chun Wu, Yifan Wang Jun 2022

New Efficient Approach To Solve Big Data Systems Using Parallel Gauss–Seidel Algorithms, Shih Yu Chang, Hsiao Chun Wu, Yifan Wang

Faculty Publications

In order to perform big-data analytics, regression involving large matrices is often necessary. In particular, large scale regression problems are encountered when one wishes to extract semantic patterns for knowledge discovery and data mining. When a large matrix can be processed in its factorized form, advantages arise in terms of computation, implementation, and data-compression. In this work, we propose two new parallel iterative algorithms as extensions of the Gauss–Seidel algorithm (GSA) to solve regression problems involving many variables. The convergence study in terms of error-bounds of the proposed iterative algorithms is also performed, and the required computation resources, namely time-and …

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Co2 Zonal Injection Rate Allocation And Plume Extent Evaluation Through Wellbore Temperature Analysis, Refaat G. Hashish, Mehdi Zeidouni Jun 2022

Co2 Zonal Injection Rate Allocation And Plume Extent Evaluation Through Wellbore Temperature Analysis, Refaat G. Hashish, Mehdi Zeidouni

Faculty Publications

Temperature analysis during a pause in injection operations, known as warmback analysis, has been used in the petroleum industry for evaluating the injection conformance and estimating the location of the flooded front in applications, such as waterflooding oil reservoirs. In this work, methods are introduced to extend the application of temperature warmback analysis to estimate the zonal CO2 injection rate and zonal CO2 plume extent during geologic CO2 storage in a saline aquifer. First, novel analytical solutions are developed to model transient temperature in the aquifer during the injection and subsequent shut-in periods considering two-phase flow (gaseous CO2 and aqueous …

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Covid-19 And Transition To Distance Learning: Perspectives Of Postsecondary Teachers In Kenya, James Ogechi Kereri, Grace Moraa Kennedy, Dovison Kereri Jun 2022

Covid-19 And Transition To Distance Learning: Perspectives Of Postsecondary Teachers In Kenya, James Ogechi Kereri, Grace Moraa Kennedy, Dovison Kereri

Faculty Publications

Several countries have transitioned to online and/or virtual learning to minimize the impact of Covid-19 on education. In Kenya, schools were closed for the better part of 2020 and reopened back on relying on an online mode and/or virtual learning. However, very little is known about the impact of such transition on postsecondary educators. Therefore, this research aims to bridge this gap by investigating the impact of online and/or virtual learning transition on postsecondary educators based on age, gender, location, and academic rank. Using a nationally distributed web-based survey, the study utilized data from 117 educators across Kenya who participated …

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Unrestricted Factor Analysis: A Powerful Alternative To Confirmatory Factor Analysis, Jan-Benedict E.M. Steenkamp, Alberto Maydeu-Olivares Jun 2022

Unrestricted Factor Analysis: A Powerful Alternative To Confirmatory Factor Analysis, Jan-Benedict E.M. Steenkamp, Alberto Maydeu-Olivares

Faculty Publications

The gold standard for modeling multiple indicator measurement data is confirmatory factor analysis (CFA), which has many statistical advantages over traditional exploratory factor analysis (EFA). In most CFA applications, items are assumed to be pure indicators of the construct they intend to measure. However, despite our best efforts, this is often not the case. Cross-loadings incorrectly set to zero can only be expressed through the correlations between the factors, leading to biased factor correlations and to biased structural (regression) parameter estimates. This article introduces a third approach, which has emerged in the psychometric literature, viz., unrestricted factor analysis (UFA). UFA …

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Are Pregnant Women With Disability Prescribed Opioids More And At Higher Dosages Than Those Without Disability?: A Retrospective Cohort Study Of South Carolina Medicaid Beneficiaries, Chelsea L. Richard Phd, Msph, Bryan L. Love Pharm.D., Nansi Boghossian, James Hardin Ph.D., Suzanne Mcdermott Jun 2022

Are Pregnant Women With Disability Prescribed Opioids More And At Higher Dosages Than Those Without Disability?: A Retrospective Cohort Study Of South Carolina Medicaid Beneficiaries, Chelsea L. Richard Phd, Msph, Bryan L. Love Pharm.D., Nansi Boghossian, James Hardin Ph.D., Suzanne Mcdermott

Faculty Publications

Background: Nationally, individuals with disability have higher rates of opioid use and misuse and are prescribed higher doses than those without disability. Opioid prescriptions during pregnancy are associated with adverse birth outcomes. Objective: To understand the difference in opioid prescribing during pregnancy over time by disability status among Medicaid beneficiaries who gave birth from 2008 to 2017 in South Carolina. Methods: Data from hospital discharges, vital records, and pharmacy were linked to determine the mother's disability status, opioid prescriptions filled during pregnancy, and other maternal characteristics. Disability status was characterized into physical disability, inflammatory conditions, intellectual and developmental disabilities (IDD), …

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In Their Own Words: Perspectives On Collection Weeding From Library Employees And Teaching Faculty, Dan Broadbent, Megan Frost, Gregory M. Nelson, David Pixton Jun 2022

In Their Own Words: Perspectives On Collection Weeding From Library Employees And Teaching Faculty, Dan Broadbent, Megan Frost, Gregory M. Nelson, David Pixton

Faculty Publications

Following a Science and Engineering collection weeding project of over 350,000 print items, our research team conducted interviews with 20 library employees and 19 teaching faculty involved in the project. The purpose of the interviews was to assess the interviewees’ perspectives and feelings relating to the time required to complete the project, inter- and intra- library communication, the decision-making processes, and their personal assessment of the costs and benefits of the project. The interviewees also offered their views of the overall project’s successes and areas for improvement. Drawing from a qualitative analysis of the interviews, we provide guidance for other …

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A Unified View Of A Human Digital Twin, Michael Miller, Emily Spatz Jun 2022

A Unified View Of A Human Digital Twin, Michael Miller, Emily Spatz

Faculty Publications

The term human digital twin has recently been applied in many domains, including medical and manufacturing. This term extends the digital twin concept, which has been illustrated to provide enhanced system performance as it combines system models and analyses with real-time measurements for an individual system to improve system maintenance. Human digital twins have the potential to change the practice of human system integration as these systems employ real-time sensing and feedback to tightly couple measurements of human performance, behavior, and environmental influences throughout a product’s life cycle to human models to improve system design and performance. However, as this …

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