Physical Sciences and Mathematics Commons^™

A Personalized And Adaptive Distribution Classification Of Actigraphy Segments Into Sleep-Wake States, Austin G. Vandegriffe, V. A. Samaranayake, Matthew S. Thimgan

Research Data

Wearable actimeters have the potential to greatly improve our understanding sleep in natural environments and in long-term experiments. Current technologies have served the sleep community well, but they have known weaknesses that introduce errors that can compromise reliable and relevant clinical and research sleep and wakefulness profiles from these data. Newer data collection technologies, such as microelectromechanical systems (MEMS), offer opportunities to gather movement data in different forms and at higher frequencies, making new analytical methods possible and potentially advantageous.

We have developed a novel statistical algorithm, called the Wasserstein Algorithm for Classifying Sleep and Wakefulness (WACSAW), that is based …

Analytical Dispatch Strategies For Pumped Storage Hydro: A Conditional Dynamic Programming Approach To Discontinuous Multi-Period Optimization Problems, Jian Liu, Jianwen Zhang, Zaiwu Gong, Donald C. Wunsch, Rui Bo

Electrical and Computer Engineering Faculty Research & Creative Works

The increasing integration of renewable energy sources like wind and solar poses significant challenges to secure and stable grid operation. Energy storage systems, particularly pumped storage hydro (PSH), play a crucial role in balancing power supply and demand. Traditional analytical studies of PSH economic dispatch problems often assume zero lower bounds for generating and pumping rates to simplify analysis and derive analytical solutions for multi-period optimization problems. However, the inherent mechanical design constraints of PSH require non-zero minimum flow rates for efficient operation. We analyze two scenarios, merchants having PSH only and merchants having both PSH and wind farms. In …

Generic Transverse Stability Of Kink Structures In Atomic And Optical Nonlinear Media With Competing Attractive And Repulsive Interactions, S. I. Mistakidis, G. Bougas, G. C. Katsimiga, P. G. Kevrekidis

Physics Faculty Research & Creative Works

We demonstrate the existence and stability of one-dimensional (1D) topological kink configurations immersed in higher-dimensional bosonic gases and nonlinear optical setups. Our analysis pertains, in particular, to the two- and three-dimensional extended Gross-Pitaevskii models with quantum fluctuations describing droplet-bearing environments but also to the two-dimensional cubic-quintic nonlinear Schrödinger equation containing higher-order corrections to the nonlinear refractive index. Contrary to the generic dark soliton transverse instability, the kink structures are generically robust under the interplay of low-amplitude attractive and high-amplitude repulsive interactions. A quasi-1D effective potential picture dictates the existence of these defects, while their stability is obtained numerically and analytically …

Synergy In Materials: Leveraging Phosphosilicate Waste Forms For Electrochemical Salt Waste, Jonathan S. Evarts, Brian J. Riley, Charmayne E. Lonergan, Michaella S. Harris, Jincheng Bai, Eric W. Bohannan, Iheanyichukwu Ajoku, Saehwa Chong, John S. Mccloy

Materials Science and Engineering Faculty Research & Creative Works

Waste forms containing glassy and crystalline phosphate and silicate phases were produced to immobilize salt waste simulants from pyro processing and characterized by using Raman spectroscopy, Mössbauer spectroscopy, X-ray diffraction, scanning electron microscopy, heat capacity, and chemical durability measurements. In this work, a phosphosilicate waste form is presented to leverage the benefits of both borosilicate glasses and iron phosphate glasses. To improve waste loading, prior to immobilization, salt simulants were successfully dechlorinated using ammonium dihydrogen phosphate, mixed with a borosilicate frit (5–30 wt. %) and Fe2O3, and vitrified. Additions of 2.5–15 wt. % borosilicate glass (NBS3) improved normalized release rates …

Per- And Polyfluoroalkyl Substance (Pfas) Degradation In Water And Soil Using Cold Atmospheric Plasma (Cap): A Review, Victor Somtochukwu Mbanugo, Boluwatife Stephen Ojo, Ta Chun Lin, Yue-Wern Huang, Marek Locmelis, Daoru Han

Biological Sciences Faculty Research & Creative Works

Per- and polyfluoroalkyl substances (PFASs) are persistent organic chemicals found in numerous industrial applications and everyday products. The excessive amounts of PFASs in water and soil, together with their link to severe health issues, have prompted substantial public concerns, making their removal from the environment a necessity. Existing degradation techniques are frequently lacking due to their low efficiency, cost-effectiveness, and potential for secondary contamination. Cold Atmospheric Plasma (CAP) technology has emerged as a promising alternative, utilizing energized reactive species to break down PFASs under ambient conditions. Therefore, this review examines the efficacy and effectiveness of CAP in degrading PFASs by …

Local Structure Of Zinc-Indium-Tin Oxide Films Via Grazing-Incidence X-Ray Pair-Distribution Functions And Theoretical Methods, G. B. González, C. J. Benmore, Julia E. Medvedeva, J. S. Okasinski, C. Riegger, O. Medina, M. M. Stulajter, T. Bsaibes, G. Cardenas, S. Cone, K. Edlund, M. Osorio, T. Holmes, I. Zhuravlev

Physics Faculty Research & Creative Works

A detailed experimental and theoretical study on the local (r ≤ 4.5 Å) atomic structure of amorphous and crystalline zinc-indium-tin oxide (ZITO) thin films using grazing-incidence x-ray Pair-Distribution Functions (PDFs), ab initio Molecular Dynamics (MD), and Empirical Potential Structure Refinement (EPSR) Monte Carlo simulations is presented. High-energy synchrotron x rays, a two-dimensional detector, and different incident angles were used to probe the depth uniformity of five (ZnO)0.15 (In2O3)0.70 (SnO2)0.15 films that were deposited via pulsed-laser deposition at growth temperatures (TG) ranging from 25 to 300 °C. Films deposited at TG ≤ 150 °C were amorphous. The partially crystalline (TG = …

Coupled Oscillators And Dielectric Function, T. Das, C. A. Ullrich, Ulrich D. Jentschura

Physics Faculty Research & Creative Works

A generalized Sellmeier model, also referred to as the Lorentz-Dirac model, has been used for the description of the dielectric function of a number of technologically important materials in the literature. This model represents the frequency-dependent dielectric function as a sum over Green functions of classical damped harmonic oscillators, much in analogy with the functional form used for the dynamic polarizability of an atom, but with one important addition, namely, a complex-valued oscillator strength in the numerator. Here, we show that this generalized functional form can be justified based on the response function of coupled damped oscillators. The encountered analogies …

Refugium Amidst Ruins: Unearthing The Lost Flora That Escaped The End-Permian Mass Extinction, Huiping Peng, Wan Yang, Mingli Wan, Jun Liu, Feng Liu

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Searching for land refugia becomes imperative for human survival during the hypothetical sixth mass extinction. Studying past comparable crises can offer insights, but there is no fossil evidence of diverse megafloral ecosystems surviving the largest Phanerozoic biodiversity crisis. Here, we investigated palynomorphs, plant, and tetrapod fossils from the Permian-Triassic South Taodonggou Section in Xinjiang, China. Our fossil records, calibrated by a high-resolution age model, reveal the presence of vibrant regional gymnospermous forests and fern fields, while marine organisms experienced mass extinction. This refugial vegetation was crucial for nourishing the substantial influx of surviving animals, thereby establishing a diverse terrestrial ecosystem …

Mineralogic Control On The Calcium And Magnesium Stable Isotopic Compositions Of Modern Microbial Carbonates, Elizabeth M. Griffith, Matthew S. Fantle, Brittan V. Wogsland, Zijian Li, Majie Fan, David J. Wronkiewicz

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Modern microbialites grow in a variety of environments including the hypersaline, turbid, low alkalinity, high magnesium (Mg) and calcium (Ca) concentrations (and Mg/Ca ∼ 4.5 mol/mol), shallow (less than 2 m deep) Storr's Lake on San Salvador Island, The Bahamas. Rather than growing via the trapping and binding of sediments, these largely micritic microbialites form via microbial processes creating crusts and mounds with laminated to clotted structures comprised of both high-Mg calcite and aragonite. The primary objective of this study was to determine whether the mineralogy of representative microbialite mounds dictates their pre-burial metal isotopic compositions. The Mg and Ca …

Irreducible Three-Loop Vacuum-Polarization Correction In Muonic Bound Systems, Gregory S. Adkins, Ulrich D. Jentschura

Physics Faculty Research & Creative Works

Three-loop electronic vacuum-polarization corrections due to irreducible diagrams are evaluated for two-body muonic ions with nuclear charge numbers 1≤Z≤6. The corrections are of order α3(Zα)2mr, where α is the fine-structure constant and mr is the reduced mass. Numerically, the energy corrections are found to be of the same order of magnitude as the largest of the order α2(Zα)6mr corrections, and are thus phenomenologically interesting. Our method of calculation eliminates numerical uncertainty encountered in other approaches.

Phases And Phase Transitions Of The Disordered Quantum Clock Model, Pulloor Kuttanikkad Vishnu, Gaurav Khairnar, Rajesh Narayanan, Thomas Vojta

Physics Faculty Research & Creative Works

We study the phases and phase transitions of a disordered one-dimensional quantum q-state clock Hamiltonian using large-scale Monte Carlo simulations. Making contact with earlier results, we confirm that the clean, translational invariant version of the model, for q=6, hosts an intermediate emergent quasi-long-range ordered (QLRO) phase between the symmetry-broken true long-range ordered (TLRO) phase and the disordered (paramagnetic) phase. With increasing disorder strength, the quasi-long-range ordered phase shrinks and finally vanishes at a multicritical point, beyond which there is a direct transition from the TLRO phase to the paramagnetic phase. After establishing the phase diagram, we characterize the critical behaviors …

A Comprehensive Survey Of Data-Driven Solutions For Lorawan: Challenges And Future Directions, Poonam Maurya, Abhishek Hazra, Preti Kumari, Troels Bundgaard Sørensen, Sajal K. Das

Computer Science Faculty Research & Creative Works

Long-range Wide-area Network (LoRaWAN) is an innovative and prominent communication protocol in the domain of Low-power Wide-area Networks (LPWAN), known for its ability to provide long-range communication with low energy consumption. However, the practical implementation of the LoRaWAN protocol, operating at the Medium Access Control layer and specially built to work upon the LoRa physical layer, presents numerous research challenges, including network congestion, interference, optimal resource allocation, collisions, scalability, and security. To mitigate these challenges effectively, the adoption of cutting-edge data-driven technologies such as Deep Learning (DL) and Machine Learning (ML) emerges as a promising approach. Interestingly, very few existing …

Terminator: A Software Package For Fast And Local Optimization Of His-Tag Placement For Protein Affinity Purification, Rokas Gerulskis, Shelley D. Minteer

Chemistry Faculty Research & Creative Works

Although the use of affinity tags can greatly improve purification of expressed enzymes, the placement of affinity tags can significantly impact the expression, solubility, and function of recombinant proteins. To facilitate the optimal design of 6xHis-tagged constructs for protein purification, we developed Terminator, a Python-based software package, which takes a UniProt ID or existing protein sequence as input, identifies related sequences, maps sequence conservation retrieved from ConSurf onto protein 3D structures retrieved from the PDB and SWISS-MODEL, and analyzes proximity to cavities and functional sites to recommend the N- or C-terminus for placement of 6xHis fusion tags 86-100% accuracy in …

Few-Shot Transfer Learning For Individualized Braking Intent Detection On Neuromorphic Hardware, Nathan A. Lutes, V. Sriram Siddhardth Nedendla, K. Krishnamurthy

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This work explores use of a few-shot transfer learning method to train and implement a convolutional spiking neural network (CSNN) on a Brain Chip Akida AKD1000 neuromorphic system-on-chip for developing individual-level, instead of traditionally used group-level, models using electroencephalographic data. The efficacy of the method is studied on an advanced driver assist system related task of predicting braking intention. Approach. Data are collected from participants operating an NVIDIA JetBot on a testbed simulating urban streets for three different scenarios. Participants receive a braking indicator in the form of: (1) an audio countdown in a nominal baseline, stress-free environment; (2) an …

Absence Of Tev Halos Around Millisecond Pulsars, A. U. Abeysekara, R. Alfaro, C. Alvarez, J. C. Arteaga-Velázquez, D. Avila Rojas, H. A. Ayala Solares, R. Babu, E. Belmont-Moreno, A. Bernal, K. S. Caballero-Mora, T. Capistrán, A. Carramiñana, S. Casanova, U. Cotti, J. Cotzomi, S. Coutiño De León, E. De La Fuente, D. Depaoli, P. Desiati, N. Di Lalla, R. Diaz Hernandez, M. A. Duvernois, J. C. Diaz-Velez, K. Engel, T. Ergin, K. L. Fan, K. Fang, N. Fraija, S. Fraija, J. A. Garcia-Gonzalez, F. Garfias, M. M. Gonzalez, J. A. Goodman, J. P. Harding, S. Hernandez-Cadena, D. Huang, F. Hueyotl-Zahuantitla, A. Iriarte, S. Kaufmann, D. Kieda, A. Lara, J. Lee, H. Leon Vargas, J. T. Linnemann, A. L. Longinotti, G. Luis-Raya, K. Malone, O. Martinez, J. Martinez-Castro, J. A. Matthews, P. Miranda-Romagnoli, J. A. Morales-Soto, E. Moreno, M. Mostafa, M. Najafi, L. Nellen, M. Newbold, M. U. Nisa, R. Noriega-Papaqui, N. Omodei, Y. Perez Araujo, E. G. Perez-Perez, C. D. Rho, D. Rosa-Gonzalez, E. Ruiz-Velasco, M. A. Roth, H. Salazar, A. Sandoval, J. Serna-Franco, Y. Son, R. W. Springer, O. Tibolla, K. Tollefson, I. Torres, R. Torres-Escobedo, R. Turner, F. Urena-Mena, E. Varela, L. Villasenor, Xiaojie Wang, Z. Wang, I. J. Watson, H. Wu, S. Yu

Physics Faculty Research & Creative Works

TeV halos are extended very-high-energy (VHE; 0.1-100 TeV) gamma-ray emission around middle-aged pulsars. So far, they have only been found around isolated pulsars, but it has been suggested that they may also be powered by millisecond pulsars (MSPs). We searched for VHE gamma-ray emission from MSPs reported by radio and GeV gamma-ray observatories in 2565 days of data from the High-Altitude Water Cherenkov (HAWC) Observatory. We found no significant emission from individual pulsars. By combining the likelihood profiles of all MSPs accessible to HAWC, our analysis suggests that the excess emission around the MSP population is consistent with a background. …

Study Of Long-Term Spectral Evolution And X-Ray And Γ-Ray Correlation Of Blazars Seen By Hawc, R. Alfaro, C. Alvarez, A. Andrés, J. C. Arteaga-Velázquez, D. Avila Rojas, H. A.Ayala Solares, R. Babu, E. Belmont-Moreno, A. Bernal, K. S. Caballero-Mora, T. Capistrán, A. Carramiñana, F. Carreón, S. Casanova, U. Cotti, J. Cotzomi, S. Coutiño De León, E. De La Fuente, D. Depaoli, N. Di Lalla, R. Diaz Hernandez, B. L. Dingus, M. A. Duvernois, M. Durocher, J. C. Diaz-Velez, K. Engel, C. Espinoza, K. L. Fan, N. Fraija, S. Fraija, J. A. Garcia-Gonzalez, F. Garfias, A. Gonzalez Munoz, M. M. Gonzalez, J. A. Goodman, S. Groetsch, J. P. Harding, S. Hernandez-Cadena, I. Herzog, D. Huang, F. Hueyotl-Zahuantitla, A. Iriarte, V. Joshi, S. Kaufman, D. Kieda, A. Lara, W. H. Lee, J. Lee, H. Leon Vargas, J. T. Linnemann, A. L. Longinotti, G. Luis-Raya, K. Malone, O. Martinez, I. Martinez-Castellanos, J. Martinez-Castro, J. A. Matthews, P. Miranda-Romagnoli, J. A. Montes, E. Moreno, M. Mostafa, A. Nayerhoda, L. Nellen, M. U. Nisa, R. Noriega-Papaqui, N. Omodei, M. Osorio, Y. Perez Araujo, E. G. Perez-Perez, C. D. Rho, D. Rosa-Gonzalez, E. Ruiz-Velasco, H. Salazar, D. Salazar-Gallegos, A. Sandoval, M. Schneider, M. Serna-Franco, A. J. Smith, Y. Son, R. W. Springer, O. Tibolla, K. Tollefson, I. Torres, R. Torres-Escobedo, R. Turner, F. Urena-Mena, E. Varela, L. Villasenor, Xiaojie Wang, I. J. Watson, K. Whitaker, E. Willox, S. Yun-Carcamo, H. Zhou

Physics Faculty Research & Creative Works

The HAWC Observatory collected 6 yr of extensive data, providing an ideal platform for long-term monitoring of blazars in the very high energy (VHE) band, without bias toward specific flux states. HAWC continuously monitors blazar activity at TeV energies, focusing on sources with a redshift of z ≤ 0.3, based on the Third Fermi-LAT Catalog of High-Energy sources. We specifically focused our analysis on Mrk 421 and Mrk 501, as they are the brightest blazars observed by the HAWC Observatory. With a data set of 2143 days, this work significantly extends the monitoring previously published, which was based on 511 …

Electro-Oxidative Deoxyfluorination Of Arenes With Net3·3hf, En Chih Liu, Sabrina M. Reich, Mayank Tanwar, Matthew Neurock, Long Luo, Melanie S. Sanford

Chemistry Faculty Research & Creative Works

This report describes the design, development, and optimization of an electrochemical deoxyfluorination of arenes using a tetrafluoropyridine-derived leaving group. NEt₃·3HF serves as the fluoride source, and the reactions are conducted using either constant potential or constant current electrolysis in an undivided electrochemical cell. Mechanistic studies support a net oxidative pathway, in which initial single-electron oxidation generates a radical cation intermediate that is trapped by fluoride. The resulting radical undergoes a second oxidation reaction, followed by the loss of the leaving group to yield the fluoroarene product.

Fourier Series For Singular Measures In Higher Dimensions, Chad Berner, John E. Herr, Palle E.T. Jorgensen, Eric S. Weber

Mathematics and Statistics Faculty Research & Creative Works

For multi-variable finite measure spaces, we present in this paper a new framework for non-orthogonal L2 Fourier expansions. Our results hold for probability measures μ with finite support in Rd that satisfy a certain disintegration condition that we refer to as "slice-singular". In this general framework, we present explicit L2(μ)-Fourier expansions, with Fourier exponentials having positive Fourier frequencies in each of the d coordinates. Our Fourier representations apply to every f∈L2(μ), are based on an extended Kaczmarz algorithm, and use a new recursive μ Rokhlin disintegration representation. In detail, our Fourier series expansion for f is in terms of the …

Unconditionally Optimal Convergent Zero-Energy-Contribution Scheme For Two Phase Mhd Model, Jinjin Yang, Shipeng Mao, Xiaoming He

Mathematics and Statistics Faculty Research & Creative Works

This paper focuses on the unconditionally optimal error estimates of a fully discrete decoupled scheme for two-phase magnetohydrodynamic (MHD) model with different viscosities and electric conductivities, by using the zero-energy-contribution (ZEC) method for the temporal discretization and mixed finite elements for the spatial discretization. Based on the ZEC property of the nonlinear and coupled terms of the model, an ordinary differential equation is designed to introduce a nonlocal scalar auxiliary variable which will play a key role in the design and the energy stability of the decoupled scheme. Combining fully explicit treatment on the nonlinear and coupled terms with the …

Application Of Convolutional Neural Network For Seismic Event Classification: Impact Of Dataset Quality, Distribution, And Human-In-The-Loop Feedback, Yanwei Zhang, Stephen S. Gao, Xiaoyi Fan, Shaohui Zhou, Junhao Qu

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Convolutional neural networks (CNNs) have gained popularity in geophysical research due to their exceptional performance in various areas. However, achieving reliable results with CNNs typically requires a significant amount of high-quality data for training. In this study, we develop a CNN to classify natural earthquakes, mine collapses, and explosions using seismic waveforms from 287 stations in Shandong Province, China. The dataset comprises 1035 earthquakes, 159 mine collapses, and 586 explosions. To address the impact of unreliable measurements, we employ cross validation to screen, manually correct, or discard measurements with inconsistent labels assigned by human experts and CNN. By refining the …

Controlling Structural Phases Of Sn Through Lattice Engineering, Chandima Kasun Edirisinghe, Anjali Rathore, Taegeon Lee, Daekwon Lee, An Hsi Chen, Garrett Baucom, Eitan Hershkovitz, Anuradha Wijesinghe, Pradip Adhikari, Sinchul Yeom, Hong Seok Lee, Hyung Kook Choi, Hyunsoo Kim, Mina Yoon

Physics Faculty Research & Creative Works

Topology and superconductivity, two distinct phenomena, offer unique insight into quantum properties and their applications in quantum technologies, spintronics, and sustainable energy technologies. Tin (Sn) plays a pivotal role here as an element because of its two structural phases, α-Sn exhibiting topological characteristics and β-Sn showing superconductivity. Here, we demonstrate precise control of these phases in Sn thin films using molecular beam epitaxy with systematically varied lattice parameters of the buffer layer. The Sn films exhibit either β-Sn or α-Sn phases as the buffer layer's lattice constant varies from 6.10Å to 6.48Å, spanning the range from GaSb (like InAs) to …

Helicity Modulus And Chiral Symmetry Breaking For Boundary Conditions With Finite Twist, Gaurav Khairnar, Thomas Vojta

Physics Faculty Research & Creative Works

We study the response of a two-dimensional classical XY model to a finite (noninfinitesimal) twist of the boundary conditions. We use Monte Carlo simulations to evaluate the free energy difference between periodic and twisted-periodic boundary conditions and find deviations from the expected quadratic dependence on the twist angle. Consequently, the helicity modulus (spin stiffness) shows a nontrivial dependence on the twist angle. We show that the deviation from the expected behavior arises because of the mixing of states with opposite chirality which leads to an additional entropy contribution in the quasi-long-range ordered phase. We give an improved prescription for the …

Anderson Transition For Light In A Three-Dimensional Random Medium, Alexey Yamilov, Hui Cao, Sergey E. Skipetrov

Physics Faculty Research & Creative Works

We study Anderson transition for light in three dimensions by performing large-scale simulations of electromagnetic wave transport in disordered ensembles of perfect-electric-conducting spatially overlapping spheres. A mobility edge that separates diffusive transport and Anderson localization is identified, revealing a sharp transition from diffusion to localization for light. Critical behavior in the vicinity of the mobility edge is well described by a single parameter scaling law. The critical exponent is found to be consistent with the value known for the Anderson transition of the orthogonal universality class. Statistical distribution of total transmission at the mobility edge is described without any fit …

Electronic Component Authenticity Identification System And Related Methods, Yunghsiao Chung, Feng Yu, Stephen Edward Saddow, Junjie Xiong

Computer Science Faculty Research & Creative Works

A method and a system for identifying authenticity of an electronic component is disclosed. The method may include obtaining chip data of an electronic component; extracting feature information of the chip data for reducing noise of the chip data; providing the feature information of the chip data to a trained deep learning model; and providing a user with an authenticity indication for the electronic component based on an output of the deep learning model. Other aspects, embodiments, and features are also claimed and described.

Reinforcing Polymer Flooding System With Dendritic Mesoporous Silica Nanoparticles For Improved Oil Recovery, Di Li, Yanling Wang, Baojun Bai, Ning Xu, Wenjing Shi, Yu Zhang, Wenhui Ding, Peixu Ma, Zan Gao

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Dendritic mesoporous silica nanoparticles (DMSNs), characterized by a high specific surface area and abundant hydroxyl groups, offer a promising approach to enhancing the performance of amphiphilic polymers in challenging enhanced oil recovery (EOR) conditions. In this study, DMSNs were successfully synthesized, and systematically evaluated for their impact on the solution properties of a betaine amphiphilic polymer (PADC). The unique "flower-like" mesoporous structure of DMSNs provided approximately 7-fold higher surface area than conventional SiO2, facilitating enhanced polymer-nanoparticle interactions. The DMSN/PADC composite system exhibited significantly improved viscosity, salt resistance, thermal tolerance, and shear resistance compared to PADC and SiO2/PADC systems. Quantum chemical …

Development And Evaluation Of Butyl Norbornene Based Cross-Linked Anion Exchange Membranes For Enhanced Nonaqueous Redox Flow Battery Efficiency, M. Motiur Mazumder, Hazel Gerber, Paul A. Kohl, Shelley D. Minteer

Chemistry Faculty Research & Creative Works

Nonaqueous redox flow batteries (NARFBs) have been plagued by the lack of appropriate separators to prevent crossover. In this article, the synthesis and characterization of poly(norbornene) (PNB) anion-exchange membranes (AEMs) were studied. PNB is a copolymer of butyl norbornene (BuNB) and bromobutyl norbornene (BrBuNB) with varying amounts of tetramethyl hexadiamine cross-linker. The performance of the AEMs was investigated in nonaqueous redox flow batteries under ideal conditions. Performance evaluation encompassed several key factors, including durability in a nonaqueous solvent, charge-carrying ions permeability, electric cell resistance, crossover of redox-active molecules, and mechanical properties. The BuNB-based AEMs outperformed the commercial Fumasep membrane in …

Detection Of Extended X-Ray Emission Around The Pevatron Microquasar V4641 Sgr With Xrism, Hiromasa Suzuki, Naomi Tsuji, Yoshiaki Kanemaru, Megumi Shidatsu, Laura Olivera-Nieto, Samar Safi-Harb, Shigeo S. Kimura, Eduardo De La Fuente, Sabrina Casanova, Kaya Mori, Xiaojie Wang, Sei Kato, Dai Tateishi, Hideki Uchiyama, Takaaki Tanaka, Hiroyuki Uchida, Shun Inoue, Dezhi Huang

Physics Faculty Research & Creative Works

A recent report on the detection of very-high-energy gamma rays from V4641 Sagittarii (V4641 Sgr) up to ≈0.8 PeV has made it the second confirmed "PeVatron" microquasar. Here we report on the observation of V4641 Sgr with X-Ray Imaging and Spectroscopy Mission (XRISM) in 2024 September. Thanks to the large field of view and low background, the CCD imager Xtend successfully detected for the first time X-ray extended emission around V4641 Sgr with a significance of ≳4.5σ and >10σ based on our imaging and spectral analysis, respectively. The spatial extent is estimated to have a radius of 7′ ± 3′ …

Collision-Free Exploration By Mobile Agents Using Pebbles, Sajal K. Das, Amit Kumar Dhar, Barun Gorain, Madhuri Mahawar

Computer Science Faculty Research & Creative Works

In this paper, we study collision-free graph exploration in an anonymous network. The network is modeled as a graph G = (V, E) where the nodes of the graph are unlabeled, and each edge incident to a node v has a unique label, called the port number, in {0, 1, ⋯, d - 1}, where d is the degree of the node v. Two identical mobile agents, starting from different nodes in G have to explore the nodes of G in such a way that for every node v in G, at least one mobile agent visits v and no …

Smevca: Stable Matching-Based Ev Charging Assignment In Subscription-Based Models, Arindam Khanda, Anurag Satpathy, Anusha Vangala, Sajal K. Das

Computer Science Faculty Research & Creative Works

The rapid shift from internal combustion engine vehicles to battery-powered electric vehicles (EVs) presents considerable challenges, such as limited charging points (CPs), unpredictable wait times for charging, and difficulty in selecting appropriate CPs for EVs. To address these challenges, we propose a novel end-to-end framework, called Stable Matching based EV Charging Assignment (SMEVCA) that efficiently assigns charge-seeking EVs to CPs with the assistance of roadside units (RSUs). The proposed framework operates within a subscription-based model, ensuring that the subscribed EVs complete their charging within a predefined time limit enforced by a service level agreement (SLA). The framework SMEVCA employs a …

Adaptive Workload Management For Enhanced Function Performance In Serverless Computing, Priyanka Ashok Birajdar, V. Harsha, Anurag Satpathy, Sourav Kanti Addya

Computer Science Faculty Research & Creative Works

Serverless computing streamlines application deployment by removing the need for infrastructure management, but fluctuating workloads make resource allocation challenging. To solve this, we propose an adaptive workload manager that intelligently balances workloads, optimizes resource use, and adapts to changes with auto-scaling, ensuring efficient and reliable serverless performance. Preliminary experiments demonstrate an ≈ 0.6X% and 2X% improvement in execution time and resource utilization compared to the First-Come-First Serve (FCFS) scheduling algorithm.