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Articles 481 - 510 of 6056

Full-Text Articles in Physical Sciences and Mathematics

Long-Range Interactions For Hydrogen Atoms In Excited D States, Chandra M. Adhikari, Ulrich D. Jentschura Mar 2022

Long-Range Interactions For Hydrogen Atoms In Excited D States, Chandra M. Adhikari, Ulrich D. Jentschura

Physics Faculty Research & Creative Works

Pressure shifts inside an atomic beam are among the more theoretically challenging effects in high-precision measurements of atomic transitions. A crucial element in their theoretical analysis is the understanding of long-range interatomic interactions inside the beam. For excited reference states, the presence of quasi-degenerate states leads to additional challenges, due to the necessity to diagonalize large matrices in the quasi-degenerate hyperfine manifolds. Here, we focus on the interactions of hydrogen atoms in reference states composed of an excited nD state (atom A), and in the metastable 2S state (atom B). We devote special attention to the cases n = 3 …

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Magic Wavelengths For 1s-Ns And 2s-Ns Transitions In Hydrogenlike Systems, Chandra M. Adhikari, Jonathan C. Canales, Thusitha P.W. Arthanayaka, Ulrich D. Jentschura Mar 2022

Magic Wavelengths For 1s-Ns And 2s-Ns Transitions In Hydrogenlike Systems, Chandra M. Adhikari, Jonathan C. Canales, Thusitha P.W. Arthanayaka, Ulrich D. Jentschura

Physics Faculty Research & Creative Works

We study the magic wavelength for two-photon 1S-nS transitions in a hydrogen and deuterium atom, as well as 2S-nS transitions, where the lower level is the metastable 2S state. At the magic wavelength, the dynamic Stark shifts of the ground and the excited state of the transition coincide, so that the transition frequency is independent of the intensity of the trapping laser field. Experimentally feasible magic wavelengths of transitions with small slopes in the atomic polarizabilities are determined; these are the most stable magic wavelengths against variations of the laser frequency. We provide data for the magic wavelengths for the …

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Fully Differential Investigation Of Two-Center Interference In Dissociative Capture In P+ H2 Collisions, S. Bastola, M. Dhital, B. Lamichhane, A. Silvus, R. Lomsadze, J. Davis, A.(Ahmad) Hasan, A. Igarashi, Michael Schulz Mar 2022

Fully Differential Investigation Of Two-Center Interference In Dissociative Capture In P+ H2 Collisions, S. Bastola, M. Dhital, B. Lamichhane, A. Silvus, R. Lomsadze, J. Davis, A.(Ahmad) Hasan, A. Igarashi, Michael Schulz

Physics Faculty Research & Creative Works

We Have Measured and Calculated Fully Differential Cross Sections for Vibrational Dissociation Following Capture in 75-KeV P+H2 Collisions. for a Molecular Orientation Perpendicular to the Projectile Beam Axis and Parallel to the Transverse Momentum Transfer We Observe a Pronounced Interference Structure. the Positions of the Interference Extrema Suggest that the Interference Term is Afflicted with a Phase Shift Which Depends on the Projectile Scattering Angle. However, No Significant Dependence on the Kinetic-Energy Release Was Observed. Considerable Discrepancies between Our Calculations and Experimental Data Were Found.

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Computational Study On The Microscopic Adsorption Characteristics Of Linear Alkylbenzene Sulfonates With Different Chain Lengths On Anthracite Surface, Xuanlai Chen, Guochao Yan, Guang Xu, Xianglin Yang, Jinfa Dong, Zidong Liang, Shuai Wei Feb 2022

Computational Study On The Microscopic Adsorption Characteristics Of Linear Alkylbenzene Sulfonates With Different Chain Lengths On Anthracite Surface, Xuanlai Chen, Guochao Yan, Guang Xu, Xianglin Yang, Jinfa Dong, Zidong Liang, Shuai Wei

Mining Engineering Faculty Research & Creative Works

In order to explore the influence of different lengths of hydrophobic carbon chains on the diffusion characteristics of surfactants on the surface of anthracite, six linear alkyl benzene sulfonates with different hydrophobic carbon chain lengths were selected (mC, m = 8, 10, 12, 14, 16, 18; m represents the numbers of carbon atoms in the hydrophobic carbon chain), and molecular dynamics (MD) simulations were adopted. Models of surfactant-anthracite, surfactant-graphite layer, and water-surfactant-anthracite were constructed. After analyzing a series of properties such as adsorption energy, diffusion coefficient, radial distribution function (RDF), and hydrophobic tail order parameters, it was found that 12C …

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Prediction Of Soil Water Content And Electrical Conductivity Using Random Forest Methods With Uav Multispectral And Ground-Coupled Geophysical Data, Yunyi Guan, Katherine R. Grote, Joel Schott, Kelsi Leverett Feb 2022

Prediction Of Soil Water Content And Electrical Conductivity Using Random Forest Methods With Uav Multispectral And Ground-Coupled Geophysical Data, Yunyi Guan, Katherine R. Grote, Joel Schott, Kelsi Leverett

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The volumetric water content (VWC) of soil is a critical parameter in agriculture, as VWC strongly influences crop yield, provides nutrients to plants, and maintains the microbes that are needed for the biological health of the soil. Measuring VWC is difficult, as it is spatially and tempo-rally heterogeneous, and most agricultural producers use point measurements that cannot fully capture this parameter. Electrical conductivity (EC) is another soil parameter that is useful in agricul-ture, since it can be used to indicate soil salinity, soil texture, and plant nutrient availability. Soil EC is also very heterogeneous; measuring EC using conventional soil sampling …

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Effect Of Interfacial Atomic Mixing On The Thermal Conductivity Of Multi-Layered Stacking Structure, Yingguang Liu, Xinqiang Xue, Guoliang Ren, Aleksandr V. Chernatynskiy Feb 2022

Effect Of Interfacial Atomic Mixing On The Thermal Conductivity Of Multi-Layered Stacking Structure, Yingguang Liu, Xinqiang Xue, Guoliang Ren, Aleksandr V. Chernatynskiy

Physics Faculty Research & Creative Works

Multi-layered stacking structures and atomic mixing interfaces were constructed. The effects of various factors on the thermal conductivity of different lattice structures were studied by non-equilibrium molecular dynamics simulations, including the number of atomic mixing layers, temperature, total length of the system, and period length. The results showed that the mixing of two and four layers of atoms can improve the thermal conductivities of the multi-layer structure with a small total length due to a phonon "bridge" mechanism. When the total length of the system is large, the thermal conductivity of the multi-layer structure with atomic mixing interfaces decreases significantly …

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Noninvasive Detection, Tracking, And Characterization Of Aerogel Implants Using Diagnostic Ultrasound, Sagar Ghimire, Martina Rodriguez Sala, Swetha Chandrasekaran, Grigorios Raptopoulos, Marcus Worsley, Patrina Paraskevopoulou, Nicholas Leventis, Firouzeh Sabri Feb 2022

Noninvasive Detection, Tracking, And Characterization Of Aerogel Implants Using Diagnostic Ultrasound, Sagar Ghimire, Martina Rodriguez Sala, Swetha Chandrasekaran, Grigorios Raptopoulos, Marcus Worsley, Patrina Paraskevopoulou, Nicholas Leventis, Firouzeh Sabri

Chemistry Faculty Research & Creative Works

Medical implants are routinely tracked and monitored using different techniques, such as MRI, X‐ray, and ultrasound. Due to the need for ionizing radiation, the two former methods pose a significant risk to tissue. Ultrasound imaging, however, is non‐invasive and presents no known risk to human tissue. Aerogels are an emerging material with great potential in biomedical implants. While qualitative observation of ultrasound images by experts can already provide a lot of infor-mation about the implants and the surrounding structures, this paper describes the development and study of two simple B‐Mode image analysis techniques based on attenuation measurements and echogenicity comparisons, …

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Multi-Walled Carbon Nanotube Supported Manganese Selenide As A Highly Active Bifunctional Oer And Orr Electrocatalyst, Harish Singh, Mckenzie Marley-Hines, Shatadru Chakravarty, Manashi Nath Feb 2022

Multi-Walled Carbon Nanotube Supported Manganese Selenide As A Highly Active Bifunctional Oer And Orr Electrocatalyst, Harish Singh, Mckenzie Marley-Hines, Shatadru Chakravarty, Manashi Nath

Chemistry Faculty Research & Creative Works

Transition metal selenides have attracted intensive interest as cost-effective electrocatalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) because of the continuous thrust in sustainable energy conversion. In this article a Mn-based bifunctional electrocatalyst, MnSe, has been identified which shows efficient OER and ORR activity in alkaline medium. The catalytic activity could be further enhanced by using multiwalled carbon nanotubes (MWCNTs) which increases the charge transfer and electronic conductivity of the catalyst composite. This MnSe@MWCNT catalyst composite exhibits a very low overpotential of 290 mV at 10 mA cm−2, which outperforms state-of-the-art RuO2 as …

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Epitaxial Electrodeposition Of Hole Transport Cuscn Nanorods On Au(111) At The Wafer Scale And Lift-Off To Produce Flexible And Transparent Foils, Bin Luo, Avishek Banik, Eric W. Bohannan, Jay A. Switzer Feb 2022

Epitaxial Electrodeposition Of Hole Transport Cuscn Nanorods On Au(111) At The Wafer Scale And Lift-Off To Produce Flexible And Transparent Foils, Bin Luo, Avishek Banik, Eric W. Bohannan, Jay A. Switzer

Chemistry Faculty Research & Creative Works

The wide bandgap p-type metal pseudohalide semiconductor copper(I) thiocyanate (CuSCN) can serve as a transparent hole transport layer in various opto-electronic applications such as perovsksite and organic solar cells and light-emitting diodes. The material deposits as one-dimensional CuSCN nanorod arrays, which are advantageous due to their high surface area and good charge transport properties. However, the growth of high-quality epitaxial CuSCN nanorods has remained a challenge. Here, we introduce a low cost and highly scalable room temperature procedure for producing epitaxial CuSCN nanorods on Au(111) by an electrochemical method. Epitaxial CuSCN grows on Au(111) with a high degree of in-plane …

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Periodicity On Isolated Time Scales, Martin Bohner, Jaqueline Mesquita, Sabrina Streipert Feb 2022

Periodicity On Isolated Time Scales, Martin Bohner, Jaqueline Mesquita, Sabrina Streipert

Mathematics and Statistics Faculty Research & Creative Works

In this work, we formulate the definition of periodicity for functions defined on isolated time scales. The introduced definition is consistent with the known formulations in the discrete and quantum calculus settings. Using the definition of periodicity, we discuss the existence and uniqueness of periodic solutions to a family of linear dynamic equations on isolated time scales. Examples in quantum calculus and for mixed isolated time scales are presented.

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On Inclusions With Monotone-Type Mappings In Nonreflexive Banach Spaces, Vy Khoi Le Feb 2022

On Inclusions With Monotone-Type Mappings In Nonreflexive Banach Spaces, Vy Khoi Le

Mathematics and Statistics Faculty Research & Creative Works

We are concerned in this article with the existence of solutions to inclusions containing generalized pseudomonotone perturbations of maximal monotone mappings in general Banach spaces. Our approach is based on a truncation–regularization technique and an extension of the Moreau–Yosida–Brezis–Crandall–Pazy regularization for maximal monotone mappings in general Banach spaces. We also consider some applications to multivalued variational inequalities containing elliptic operators with rapidly growing coefficients in Orlicz–Sobolev spaces.

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On-Demand Generation Of Dark-Bright Soliton Trains In Bose-Einstein Condensates, A. Romero-Ros, Garyfallia C. Katsimiga, P. G. Kevrekidis, B. Prinari, G. Biondini, P. Schmelcher Feb 2022

On-Demand Generation Of Dark-Bright Soliton Trains In Bose-Einstein Condensates, A. Romero-Ros, Garyfallia C. Katsimiga, P. G. Kevrekidis, B. Prinari, G. Biondini, P. Schmelcher

Physics Faculty Research & Creative Works

The controlled creation of dark-bright (DB) soliton trains in multicomponent Bose-Einstein condensates (BECs) is a topic of ongoing interest. In this work we generalize earlier findings on the creation of dark soliton trains in single-component BECs [A. Romero-Ros, Phys. Rev. A 103, 023329 (2021)2469-992610.1103/PhysRevA.103.023329] to two-component BECs. By choosing suitable filled box-type initial configurations (FBTCs) and solving the direct scattering problem for the defocusing vector nonlinear Schrödinger equation with nonzero boundary conditions we obtain analytical expressions for the DB soliton solutions produced by a general FBTC. It is found that the size of the initial box and the amount of …

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Special Issue: Microbiota-Gut-Brain Axis, Mark Obrenovich, Prakash Reddy Feb 2022

Special Issue: Microbiota-Gut-Brain Axis, Mark Obrenovich, Prakash Reddy

Chemistry Faculty Research & Creative Works

No abstract provided.

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Collisional Excitation And Non-Lte Modeling Of Interstellar Chiral Propylene Oxide, Karlis Dzenis, Alexandre Faure, B. A. Mcguire, A. J. Remijan, P. J. Dagdigian, C. Rist, Richard Dawes, Ernesto Quintas-Sánchez, F. Lique, M. Hochlaf Feb 2022

Collisional Excitation And Non-Lte Modeling Of Interstellar Chiral Propylene Oxide, Karlis Dzenis, Alexandre Faure, B. A. Mcguire, A. J. Remijan, P. J. Dagdigian, C. Rist, Richard Dawes, Ernesto Quintas-Sánchez, F. Lique, M. Hochlaf

Chemistry Faculty Research & Creative Works

The first set of theoretical rotational cross sections for propylene oxide (CH3CHCH2O) colliding with cold He atoms has been obtained at the full quantum level using a high-accuracy potential energy surface. By scaling the collision reduced mass, rotational rate coefficients for collisions with para-H2 are deduced in the temperature range 5-30 K. These collisional coefficients are combined with radiative data in a non-LTE radiative transfer model in order to reproduce observations of propylene oxide made toward the Sagittarius B2(N) molecular cloud with the Green Bank and Parkes radio telescopes. The three detected absorption lines are …

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A Novel Branched Polymer Gel System With Delayed Gelation Property For Conformance Control, Tao Song, Qi Feng, Thomas P. Schuman, Jie Cao, Baojun Bai Feb 2022

A Novel Branched Polymer Gel System With Delayed Gelation Property For Conformance Control, Tao Song, Qi Feng, Thomas P. Schuman, Jie Cao, Baojun Bai

Chemistry Faculty Research & Creative Works

Excessive water production from oil reservoirs not only affects the economical production of oil, but it also results in serious environmental concerns. Polymer gels have been widely applied to decrease water production and thus improve oil production. However, traditional polymer gels such as partially hydrolyzed polyacrylamide (HPAM)/chromium (III) gel systems usually have a short gelation time and cannot meet the requirement of some conformance control projects. This paper introduces a novel polymer gel system of which crosslinking time can be significantly delayed. A branched polymer grafted from arginine by the surface initiation method is synthesized as the backbone, chromium acetate …

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Collisional Excitation And Non-Lte Modeling Of Interstellar Chiral Propylene Oxide, Karlis Dzenis, Alexandre Faure, B. A. Mcguire, A. J. Remijan, P. J. Dagdigian, C. Rist, Richard Dawes, Ernesto Quintas-Sánchez, F. Lique, M. Hochlaf Feb 2022

Collisional Excitation And Non-Lte Modeling Of Interstellar Chiral Propylene Oxide, Karlis Dzenis, Alexandre Faure, B. A. Mcguire, A. J. Remijan, P. J. Dagdigian, C. Rist, Richard Dawes, Ernesto Quintas-Sánchez, F. Lique, M. Hochlaf

Chemistry Faculty Research & Creative Works

The first set of theoretical rotational cross sections for propylene oxide (CH3CHCH2O) colliding with cold He atoms has been obtained at the full quantum level using a high-accuracy potential energy surface. By scaling the collision reduced mass, rotational rate coefficients for collisions with para-H2 are deduced in the temperature range 5-30 K. These collisional coefficients are combined with radiative data in a non-LTE radiative transfer model in order to reproduce observations of propylene oxide made toward the Sagittarius B2(N) molecular cloud with the Green Bank and Parkes radio telescopes. The three detected absorption lines are found …

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Noninvasive Detection, Tracking, And Characterization Of Aerogel Implants Using Diagnostic Ultrasound, Sagar Ghimire, Martina Rodriguez Sala, Swetha Chandrasekaran, Grigorios Raptopoulos, Marcus Worsley, Patrina Paraskevopoulou, Nicholas Leventis, Firouzeh Sabri Feb 2022

Noninvasive Detection, Tracking, And Characterization Of Aerogel Implants Using Diagnostic Ultrasound, Sagar Ghimire, Martina Rodriguez Sala, Swetha Chandrasekaran, Grigorios Raptopoulos, Marcus Worsley, Patrina Paraskevopoulou, Nicholas Leventis, Firouzeh Sabri

Chemistry Faculty Research & Creative Works

Medical implants are routinely tracked and monitored using different techniques, such as MRI, X‐ray, and ultrasound. Due to the need for ionizing radiation, the two former methods pose a significant risk to tissue. Ultrasound imaging, however, is non‐invasive and presents no known risk to human tissue. Aerogels are an emerging material with great potential in biomedical implants. While qualitative observation of ultrasound images by experts can already provide a lot of infor-mation about the implants and the surrounding structures, this paper describes the development and study of two simple B‐Mode image analysis techniques based on attenuation measurements and echogenicity comparisons, …

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High Harmonic Generation In Mixed Xuv And Nir Fields At A Free-Electron Laser, Jan Troß, Shashank Pathak, Adam Summers, Dimitrios Rompotis, Benjamin Erk, Christopher Passow, Bastian Manschwetus, Rebecca Boll, Patrik Grychtol, Sadia Bari, Vinod Kumarappan, Anh(Anh-Thu) Thu Le, Cheng Jin, Carlos Trallero Feb 2022

High Harmonic Generation In Mixed Xuv And Nir Fields At A Free-Electron Laser, Jan Troß, Shashank Pathak, Adam Summers, Dimitrios Rompotis, Benjamin Erk, Christopher Passow, Bastian Manschwetus, Rebecca Boll, Patrik Grychtol, Sadia Bari, Vinod Kumarappan, Anh(Anh-Thu) Thu Le, Cheng Jin, Carlos Trallero

Physics Faculty Research & Creative Works

We Present the Results of an Experiment Investigating the Generation of High-Order Harmonics by a Femtosecond Near-Infrared (NIR) Laser Pulse in the Presence of an Extreme Ultraviolet (XUV) Field Provided by a Free-Electron Laser (FEL), a Process Referred to as XUV-Assisted High-Order Harmonic Generation (HHG). Our Experimental Findings Show that the XUV Field Can Lead to a Small Enhancement in the Harmonic Yield When the XUV and NIR Pulses overlap in Time, while a Strong Decrease of the HHG Yield and a Red Shift of the HHG Spectrum is Observed When the XUV Precedes the NIR Pulse. the Latter Observations …

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Speeding Up Routing Schedules On Aisle Graphs With Single Access, Francesco Betti Sorbelli, Stefano Carpin, Federico Coro, Sajal K. Das, Alfredo Navarra, Cristina M. Pinotti Feb 2022

Speeding Up Routing Schedules On Aisle Graphs With Single Access, Francesco Betti Sorbelli, Stefano Carpin, Federico Coro, Sajal K. Das, Alfredo Navarra, Cristina M. Pinotti

Computer Science Faculty Research & Creative Works

In this article, we study the orienteering aisle-graph single-access problem (OASP), a variant of the orienteering problem for a robot moving in a so-called single-access aisle graph, i.e., a graph consisting of a set of rows that can be accessed from one side only. Aisle graphs model, among others, vineyards or warehouses. Each aisle-graph vertex is associated with a reward that a robot obtains when it visits the vertex itself. As the energy of the robot is limited, only a subset of vertices can be visited with a fully charged battery. The objective is to maximize the total reward collected …

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Comprehensive Evaluation Of A High-Temperature Resistant Re-Crosslinkable Preformed Particle Gel For Water Management, Bowen Yu, Shuda Zhao, Yifu Long, Baojun Bai, Thomas P. Schuman Feb 2022

Comprehensive Evaluation Of A High-Temperature Resistant Re-Crosslinkable Preformed Particle Gel For Water Management, Bowen Yu, Shuda Zhao, Yifu Long, Baojun Bai, Thomas P. Schuman

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Gel treatment has been widely applied to control conformance for improving oil recovery and control water production in mature oil fields. However, most of the hydrogel systems are limited when being applied in the harsh environments of high temperatures. A systematic evaluation was conducted in this study to evaluate a modified PPG product, the high temperature resistant re-crosslinkable preformed particle gel (HT-RPPG) which can re-crosslink to form a bulky material and keep thermostable in the large-opening features after placement. This material was developed to overcome the limitations of conventional PPGs in the reservoirs with large- opening features such as open …

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A Multigrid Multilevel Monte Carlo Method For Stokes–Darcy Model With Random Hydraulic Conductivity And Beavers–Joseph Condition, Zhipeng Yang, Ju Ming, Changxin Qiu, Maojun Li, Xiaoming He Feb 2022

A Multigrid Multilevel Monte Carlo Method For Stokes–Darcy Model With Random Hydraulic Conductivity And Beavers–Joseph Condition, Zhipeng Yang, Ju Ming, Changxin Qiu, Maojun Li, Xiaoming He

Mathematics and Statistics Faculty Research & Creative Works

A multigrid multilevel Monte Carlo (MGMLMC) method is developed for the stochastic Stokes–Darcy interface model with random hydraulic conductivity both in the porous media domain and on the interface. Three interface conditions with randomness are considered on the interface between Stokes and Darcy equations, especially the Beavers–Joesph interface condition with random hydraulic conductivity. Because the randomness through the interface affects the flow in the Stokes domain, we investigate the coupled stochastic Stokes–Darcy model to improve the fidelity. Under suitable assumptions on the random coefficient, we prove the existence and uniqueness of the weak solution of the variational form. To construct …

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Metallic Networks And Hydrogen Compensation In Highly Nonstoichiometric Amorphous In₂O₃₋ₓ, Julia E. Medvedeva, E. Caputa-Hatley, I. Zhuravlev Feb 2022

Metallic Networks And Hydrogen Compensation In Highly Nonstoichiometric Amorphous In₂O₃₋ₓ, Julia E. Medvedeva, E. Caputa-Hatley, I. Zhuravlev

Physics Faculty Research & Creative Works

The unique response of amorphous ionic oxides to changes in oxygen stoichiometry is investigated using computationally intensive ab initio molecular dynamics simulations, comprehensive structural analysis, and hybrid density-functional calculations for the oxygen defect formation energy and electronic properties of amorphous In2O3-x with x = 0-0.185. In marked contrast to nonstoichiometric crystalline nanocomposites with clusters of metallic inclusions inside an insulating matrix, the lack of oxygen in amorphous indium oxide is distributed between a large fraction of undercoordinated In atoms, leading to an extended shallow state for x < 0.037, a variety of weakly and strongly localized states for 0.074 < x < 0.148, and a percolation-like network of single-atom chains of metallic In-In bonds for x > 0.185. The calculated carrier concentration increases from 3.3 x 10 …

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The Shepherd Mountain Iron Ore Deposit In Southeast Missouri, Usa -- An Extension Of The Pilot Knob Magmatic-Hydrothermal Ore System: Evidence From Iron Oxide Chemistry, Bolorchimeg N. Tunnell, Marek Locmelis, Cheryl Seeger, Marilena Moroni, Sarah Dare, Ryan Mathur, Brandon Sullivan Feb 2022

The Shepherd Mountain Iron Ore Deposit In Southeast Missouri, Usa -- An Extension Of The Pilot Knob Magmatic-Hydrothermal Ore System: Evidence From Iron Oxide Chemistry, Bolorchimeg N. Tunnell, Marek Locmelis, Cheryl Seeger, Marilena Moroni, Sarah Dare, Ryan Mathur, Brandon Sullivan

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The Southeast Missouri Iron Metallogenic Province in the Midcontinent USA contains seven major and several minor IOA/IOCG-type deposits and a series of shallow vein-type deposits/prospects, all of which are spatially and temporally associated with early Mesoproterozoic (1500–1440 Ma) magmatism in the St. Francois Mountains terrane. One of the vein-type deposits is the Shepherd Mountain deposit, which consists of two northeast-trending ore veins dominated by magnetite and lesser amounts of hematite. Here we report the findings of a study that investigates the origin of the Shepherd Mountain deposit and a possible genetic link to the nearby (i.e., < 5 km away) magmatic to magmatic-hydrothermal Pilot Knob ore system that comprises the massive-to-disseminated Pilot Knob Magnetite deposit and the overlying bedded and brecciated Pilot Knob Hematite deposit. Petrographic observations, whole-rock data and the trace element and Fe isotope composition of magnetite and hematite show that the Shepherd Mountain deposit formed from at least five pulses of magmatic-hydrothermal fluids with different compositions and physicochemical parameters. Integration of the data for the Shepherd Mountain deposit with new and published data from the Pilot Knob Magnetite and Pilot Knob Hematite deposits shows that the three deposits are genetically linked through two local faults. The Ironton and Pilot Knob faults provided fluid pathways that connected the Pilot Knob Magnetite deposit to the shallower Shepherd Mountain and Pilot Knob Hematite deposits. Consequently, we argue that the Shepherd Mountain and Pilot Knob Hematite deposits are near-surface extensions of the same magmatic to hydrothermal plumbing system that formed the Pilot Knob Magnetite deposit at depth.

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Special Issue: Microbiota–Gut–Brain Axis, Mark Obrenovich, V. (Prakash) Reddy Feb 2022

Special Issue: Microbiota–Gut–Brain Axis, Mark Obrenovich, V. (Prakash) Reddy

Chemistry Faculty Research & Creative Works

No abstract provided.

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Metallic Networks And Hydrogen Compensation In Highly Nonstoichiometric Amorphous In2 O3-X, Julia E. Medvedeva, E. Caputa-Hatley, I. Zhuravlev Feb 2022

Metallic Networks And Hydrogen Compensation In Highly Nonstoichiometric Amorphous In2 O3-X, Julia E. Medvedeva, E. Caputa-Hatley, I. Zhuravlev

Physics Faculty Research & Creative Works

The unique response of amorphous ionic oxides to changes in oxygen stoichiometry is investigated using computationally intensive ab initio molecular dynamics simulations, comprehensive structural analysis, and hybrid density-functional calculations for the oxygen defect formation energy and electronic properties of amorphous In2O3-x with x=0-0.185. In marked contrast to nonstoichiometric crystalline nanocomposites with clusters of metallic inclusions inside an insulating matrix, the lack of oxygen in amorphous indium oxide is distributed between a large fraction of undercoordinated In atoms, leading to an extended shallow state for x0.185. The calculated carrier concentration increases from 3.3x1020cm-3 at x=0.037 to 6.6x1020cm-3 at x=0.074 and decreases …

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Fedvcp: A Federated-Learning-Based Cooperative Positioning Scheme For Social Internet Of Vehicles, Xiangjie Kong, Haoran Gao, Guojiang Shen, Gaohui Duan, Sajal K. Das Feb 2022

Fedvcp: A Federated-Learning-Based Cooperative Positioning Scheme For Social Internet Of Vehicles, Xiangjie Kong, Haoran Gao, Guojiang Shen, Gaohui Duan, Sajal K. Das

Computer Science Faculty Research & Creative Works

Intelligent vehicle applications, such as autonomous driving and collision avoidance, put forward a higher demand for precise positioning of vehicles. The current widely used global navigation satellite systems (GNSS) cannot meet the precision requirements of the submeter level. Due to the development of sensing techniques and vehicle-to-infrastructure (V2I) communications, some vehicles can interact with surrounding landmarks to achieve precise positioning. Existing work aims to realize the positioning correction of common vehicles by sharing the positioning data of sensor-rich vehicles. However, the privacy of trajectory data makes it difficult to collect and train data centrally. Moreover, uploading vehicle location data wastes …

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The Molecular Structure And Curious Motions In 1,1-Difluorosilacyclopent-3-Ene And Silacyclopent-3-Ene As Determined By Microwave Spectroscopy And Quantum Chemical Calculations, Thomas M.C. Mcfadden, Nicole Moon, Frank E. Marshall, Amanda J. Duerden, Esther J. Ocola, Jaan Laane, Gamil A. Guirgis, Garry S. Grubbs Jan 2022

The Molecular Structure And Curious Motions In 1,1-Difluorosilacyclopent-3-Ene And Silacyclopent-3-Ene As Determined By Microwave Spectroscopy And Quantum Chemical Calculations, Thomas M.C. Mcfadden, Nicole Moon, Frank E. Marshall, Amanda J. Duerden, Esther J. Ocola, Jaan Laane, Gamil A. Guirgis, Garry S. Grubbs

Chemistry Faculty Research & Creative Works

The molecules 1,1-difluorosilacyclopent-3-ene (3SiCPF2) and silacyclopent-3-ene (3SiCP) have been synthesized and studied using chirped pulse, Fourier transform microwave (CP-FTMW) spectroscopy. For 3SiCP this is the first ever microwave study of the molecule and, for 3SiCPF2, the spectra reported in this work have been combined with that of previous work in a global fit. The spectra of each contain splitting which has been fit using a Hamiltonian consisting of semirigid and Coriolis coupling parameters. A refit of the original 3SiCPF2 work was also carried out. All fits and approaches are reported. Analyses of the spectra provide evidence that the molecule is …

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Characterization Of Single-Shot Attosecond Pulses With Angular Streaking Photoelectron Spectra, Xi Zhao, Siqi Li, Taran Driver, Van Hung Hoang, Anh-Thu Le, James P. Cryan, Agostino Marinelli, C. D. Lin Jan 2022

Characterization Of Single-Shot Attosecond Pulses With Angular Streaking Photoelectron Spectra, Xi Zhao, Siqi Li, Taran Driver, Van Hung Hoang, Anh-Thu Le, James P. Cryan, Agostino Marinelli, C. D. Lin

Physics Faculty Research & Creative Works

Most of the traditional attosecond pulse retrieval algorithms are based on a so-called attosecond streak camera technique, in which the momentum of the electron is shifted by an amount depending on the relative time delay between the attosecond pulse and the streaking infrared pulse. Thus, temporal information of the attosecond pulse is encoded in the amount of momentum shift in the streaked photoelectron momentum spectrogram S(p, τ), where p is the momentum of the electron along the polarization direction and τ is the time delay. An iterative algorithm is then employed to reconstruct the attosecond pulse from the streaking spectrogram. …

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Search For Continuous Gravitational Waves From 20 Accreting Millisecond X-Ray Pulsars In O3 Ligo Data, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, Marco Cavaglia, For Full List Of Authors, See Publisher's Website. Jan 2022

Search For Continuous Gravitational Waves From 20 Accreting Millisecond X-Ray Pulsars In O3 Ligo Data, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

Results are presented of searches for continuous gravitational waves from 20 accreting millisecond x-ray pulsars with accurately measured spin frequencies and orbital parameters, using data from the third observing run of the Advanced LIGO and Advanced Virgo detectors. The search algorithm uses a hidden Markov model, where the transition probabilities allow the frequency to wander according to an unbiased random walk, while the J-statistic maximum-likelihood matched filter tracks the binary orbital phase. Three narrow subbands are searched for each target, centered on harmonics of the measured spin frequency. The search yields 16 candidates, consistent with a false alarm probability of …

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Stripe Order, Impurities, And Symmetry Breaking In A Diluted Frustrated Magnet, Xuecheng Ye, Rajesh Narayanan, Thomas Vojta Jan 2022

Stripe Order, Impurities, And Symmetry Breaking In A Diluted Frustrated Magnet, Xuecheng Ye, Rajesh Narayanan, Thomas Vojta

Physics Faculty Research & Creative Works

We investigate the behavior of the frustrated J1-J2 Ising model on a square lattice under the influence of random dilution and spatial anisotropies. Spinless impurities generate a random-field type disorder for the spin-density wave (stripe) order parameter. These random fields destroy the long-range stripe order in the case of spatially isotropic interactions. Combining symmetry arguments, percolation theory, and large-scale Monte Carlo simulations, we demonstrate that arbitrarily weak spatial interaction anisotropies restore the stripe phase. More specifically, the transition temperature Tc into the stripe phase depends on the interaction anisotropy ΔJ via Tc∼1/|ln(ΔJ)| for small …

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