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Articles 451 - 480 of 5948

Full-Text Articles in Physical Sciences and Mathematics

First Measurement Of Hard Exclusive š›‘ā»Ī”āŗāŗ Electroproduction Beam-Spin Asymmetries Off The Proton, S. Diehl, N. Trotta, K. Joo, P. Achenbach, Z. Akbar, W. R. Armstrong, H. Atac, H. Avakian, L. Baashen, N. A. Baltzell, L. Barion, M. Bashkanov, M. Battaglieri, I. Bedlinskiy, F. Benmokhtar, A. Bianconi, A. S. Biselli, F. BossĆ¹, K.-T. Brinkman, M. Zurek, Et Al., Clas Collaboration Jan 2023

First Measurement Of Hard Exclusive š›‘ā»Ī”āŗāŗ Electroproduction Beam-Spin Asymmetries Off The Proton, S. Diehl, N. Trotta, K. Joo, P. Achenbach, Z. Akbar, W. R. Armstrong, H. Atac, H. Avakian, L. Baashen, N. A. Baltzell, L. Barion, M. Bashkanov, M. Battaglieri, I. Bedlinskiy, F. Benmokhtar, A. Bianconi, A. S. Biselli, F. BossĆ¹, K.-T. Brinkman, M. Zurek, Et Al., Clas Collaboration

Physics Faculty Publications

The polarized cross-section ratio ĻƒLTā€²/Ļƒ0 from hard exclusive Ļ€āˆ’Ī”++ electroproduction off an unpolarized hydrogen target has been extracted based on beam-spin asymmetry measurements using a 10.2ā€‰ā€‰GeV/10.6ā€‰ā€‰GeV incident electron beam and the CLAS12 spectrometer at Jefferson Lab. The study, which provides the first observation of this channel in the deep-inelastic regime, focuses on very forward-pion kinematics in the valence regime, and photon virtualities ranging from 1.5ā€‰ā€‰GeV2 up to 7ā€‰ā€‰GeV2. The reaction provides a novel access to the d-quark content of the nucleon and to pā†’Ī”++ transition generalized parton ā€¦


Searching For Prompt And Long-Lived Dark Photons In Electroproduced Eāŗ Eā» Pairs With The Heavy Photon Search Experiment At Jlab, P. H. Adrian, N. A. Baltzell, M. Battaglieri, M. BondĆ­, S. Boyarinov, S. Bueltmann, P. Butti, V. D. Burkert, D. Calvo, T. Cao, M. Carpinelli, A. Celentano, G. Charles, L. Colaneri, W. Cooper, D. Crowe, C. Cuevas, A. D'Angelo, N. Dashyan, B. Wojtsekhowski, Et Al. Jan 2023

Searching For Prompt And Long-Lived Dark Photons In Electroproduced Eāŗ Eā» Pairs With The Heavy Photon Search Experiment At Jlab, P. H. Adrian, N. A. Baltzell, M. Battaglieri, M. BondĆ­, S. Boyarinov, S. Bueltmann, P. Butti, V. D. Burkert, D. Calvo, T. Cao, M. Carpinelli, A. Celentano, G. Charles, L. Colaneri, W. Cooper, D. Crowe, C. Cuevas, A. D'Angelo, N. Dashyan, B. Wojtsekhowski, Et Al.

Physics Faculty Publications

The heavy photon search experiment (HPS) at the Thomas Jefferson National Accelerator Facility searches for electroproduced dark photons. We report results from the 2016 engineering run consisting of 10ā€‰608ā€‰ā€‰nbāˆ’1 of data for both the prompt and displaced vertex searches. A search for a prompt resonance in the e+eāˆ’ invariant mass distribution between 39 and 179 MeV showed no evidence of dark photons above the large QED background, limiting the coupling of Īµ2ā‰³10āˆ’5, in agreement with previous searches. The search for displaced vertices showed no evidence of excess signal over background ā€¦


Surface Properties And Rf Performance Of Vapor Diffused Nbā‚ƒSn On Nb After Sequential Anneals Below 1000 Ā°C, Jayendrika K. Tiskumara, Jean R. Delayen, U. Pudasaini, G. Eremeev Jan 2023

Surface Properties And Rf Performance Of Vapor Diffused Nbā‚ƒSn On Nb After Sequential Anneals Below 1000 Ā°C, Jayendrika K. Tiskumara, Jean R. Delayen, U. Pudasaini, G. Eremeev

Physics Faculty Publications

Nbā‚ƒSn is a next-generation superconducting material that can be used for future superconducting radiofrequency (SRF) accelerator cavities, promising better performance, cost reduction, and higher operating temperature than Nb. The Sn vapor diffusion method is currently the most preferred and successful technique to coat niobium cavities with Nbā‚ƒSn. Among post-coating treatments to optimize the coating quality, higher temperature annealing without Sn is known to degrade Nbā‚ƒSn because of Sn loss. We have investigated Nbā‚ƒSn/Nb samples briefly annealed at 800-1000 Ā°C, for 10 and 20 minutes to potentially improve the surface to enhance the performance of Nbā‚ƒSn-coated cavities. Following the sample studies, ā€¦


Magnetic Field Mapping Of A Large-Grain 1.3 Ghz Single-Cell Cavity, Ishwari Prasad Parajuli, Jean R. Delayen, Alex V. Gurevich, Gianluigi Ciovati Jan 2023

Magnetic Field Mapping Of A Large-Grain 1.3 Ghz Single-Cell Cavity, Ishwari Prasad Parajuli, Jean R. Delayen, Alex V. Gurevich, Gianluigi Ciovati

Physics Faculty Publications

A new magnetic field mapping system for 1.3 GHz single-cell cavities was developed in order to reveal the impact of ambient magnetic field and temperature gradients during cool-down on the flux trapping phenomenon. Measurements were done at 2 K for different cool-down conditions of a large-grain cavity before and after 120 Ā°C bake. The fraction of applied magnetic field trapped in the cavity walls was ~ 50% after slow cool-down and ~ 20% after fast cool-down. The results showed a weak correlation between between trapped flux locations and hot-spots causing the high-field Q-slope. The results also showed an increase of ā€¦


Development And Performance Of Rfd Crab Cavity Prototypes For Hl-Lhc Aup, L. Listori, P. Berrutti, M. Narduzzi, A. Castilla, S. U. De Silva, J. R. Delayen, N. A. Huque, Z. Li, A. Ratti Jan 2023

Development And Performance Of Rfd Crab Cavity Prototypes For Hl-Lhc Aup, L. Listori, P. Berrutti, M. Narduzzi, A. Castilla, S. U. De Silva, J. R. Delayen, N. A. Huque, Z. Li, A. Ratti

Physics Faculty Publications

The US will be contributing to the HL-LHC upgrade at CERN with the fabrication and qualification of RFD crabbing cavities in the framework of the HL-LHC Accelerator Upgrade Project (AUP) managed by Fermilab. AUP received Critical Decision 3 (CD-3) approval by DOE in December 2020 launching the project into the production phase. The electro-magnetic design of the cavity was inherited from the LHC Accelerator Research Program (LARP) but needed to be revised to meet new project requirements and to prevent issues encountered during beam tests performed at CERN in the R&D phase. Two prototype cavities were manufactured in industry and ā€¦


Fabrication And Testing Of A Prototype Rf-Dipole Crabbing Cavity, S. U. De Silva, J. R. Delayen, H. Park Jan 2023

Fabrication And Testing Of A Prototype Rf-Dipole Crabbing Cavity, S. U. De Silva, J. R. Delayen, H. Park

Physics Faculty Publications

Crabbing cavities are essential in particle colliders to compensate the luminosity degradation due to beam collision at a crossing angle. The 952.6 MHz 2-cell rf-dipole crabbing cavity system was proposed for the Jefferson Lab Electron-Ion Collider to restore the head-on collisions of electron and proton bunches at the interaction point. A prototype cavity was designed and developed to demonstrate the performance of multi-cell rf-dipole structures. This paper presents the fabrication process and cold test results of the first 2-cell rf-dipole prototype cavity.


Measurement Of The J/š›¹ Photoproduction Cross Section Over The Full Near-Threshold Kinematic Region, S. Adhikari, F. Afzal, C.S. Akondi, M. Albrecht, M. Amaryan, V. Arroyave, A. Asaturyan, A. Austregesilo, Z. Baldwin, F. Barbosa, J. Barlow, E. Barriga, R. Barsotti, T. D. Beattie, V. V. Berdnikov, T. Black, W. Boeglin, W. J. Briscoe, T. Britton, B. Zihlmann Jan 2023

Measurement Of The J/š›¹ Photoproduction Cross Section Over The Full Near-Threshold Kinematic Region, S. Adhikari, F. Afzal, C.S. Akondi, M. Albrecht, M. Amaryan, V. Arroyave, A. Asaturyan, A. Austregesilo, Z. Baldwin, F. Barbosa, J. Barlow, E. Barriga, R. Barsotti, T. D. Beattie, V. V. Berdnikov, T. Black, W. Boeglin, W. J. Briscoe, T. Britton, B. Zihlmann

Physics Faculty Publications

We report the total and differential cross sections for J/Ļˆ photoproduction with the large acceptance GlueX spectrometer for photon beam energies from the threshold at 8.2 GeV up to 11.44 GeV and over the full kinematic range of momentum transfer squared, t. Such coverage facilitates the extrapolation of the differential cross sections to the forward (t=0) point beyond the physical region. The forward cross section is used by many theoretical models and plays an important role in understanding J/Ļˆ photoproduction and its relation to the J/Ļˆ-proton interaction. These measurements of J/Ļˆ photoproduction near threshold are also crucial inputs to theoretical ā€¦


Three-Body Scattering And Quantization Conditions From S-Matrix Unitarity, Andrew W. Jackura Jan 2023

Three-Body Scattering And Quantization Conditions From S-Matrix Unitarity, Andrew W. Jackura

Physics Faculty Publications

Two methodologies have been presented in the literature which connect relativistic three-particle scattering amplitudes with lattice QCD spectraā€”the ā€œrelativistic effective field theoryā€ approach and the ā€œfinite-volume unitarityā€ method. While both methods have been shown to be equivalent in various works, it has not been shown how to arrive at the relativistic effective field theory results directly from S-matrix unitarity. In this work, we provide a simple proof of the relativistic effective field theory form of the scattering equations directly from unitarity. Motivated by the finite-volume unitarity approach, we then postulate a set of quantization conditions which relate the finite-volume energy ā€¦


Analytic Continuation Of The Relativistic Three-Particle Scattering Amplitudes, Sebastian M. Dawid, Md Habib E. Islam, RaĆŗl A. BriceƱo Jan 2023

Analytic Continuation Of The Relativistic Three-Particle Scattering Amplitudes, Sebastian M. Dawid, Md Habib E. Islam, RaĆŗl A. BriceƱo

Physics Faculty Publications

We investigate the relativistic scattering of three identical scalar bosons interacting via pair-wise interactions. Extending techniques from the nonrelativistic three-body scattering theory, we provide a detailed and general prescription for solving and analytically continuing integral equations describing the three-body reactions. We use these techniques to study a system with zero angular momenta described by a single scattering length leading to a bound state in a two-body subchannel. We obtain bound-state-particle and three-particle amplitudes in the previously unexplored kinematical regime; in particular, for real energies below elastic thresholds and complex energies in the physical and unphysical Riemann sheets. We extract positions ā€¦


Eic 197 Mhz Crab Cavity Rf Optimization, Zenghai Li, Subashini U. De Silva, Jean R. Delayen, Robert A. Rimmer, Qiong Wu, Binping Xiao, Wencan Xu Jan 2023

Eic 197 Mhz Crab Cavity Rf Optimization, Zenghai Li, Subashini U. De Silva, Jean R. Delayen, Robert A. Rimmer, Qiong Wu, Binping Xiao, Wencan Xu

Physics Faculty Publications

Crab cavities, operating at 197 MHz and 394 MHz respectively, will be used to compensate the loss of luminosity due to a 25 mrad crossing angle at the interaction point in the Electron Ion Collider (EIC). Both crab cavities are of the RF Dipole (RFD) shape. To meet the machine design requirements, there are a few important cavity design considerations that need to be addressed. First, to achieve stable cavity operation at the design voltages, cavity geometry details must be optimized to suppress potential multipacting. Incorporating strong HOM damping in the cavity design is required for the beam stability and ā€¦


Temperature, Rf Field, And Frequency Dependence Performance Evaluation Of Superconducting Niobium Half-Wave Coaxial Cavity, N. K. Raut, G. Ciovati, S. U. De Silva, J. R. Delayen, P. Dhakal, B. D. Khanal, J. K. Tiskumara Jan 2023

Temperature, Rf Field, And Frequency Dependence Performance Evaluation Of Superconducting Niobium Half-Wave Coaxial Cavity, N. K. Raut, G. Ciovati, S. U. De Silva, J. R. Delayen, P. Dhakal, B. D. Khanal, J. K. Tiskumara

Physics Faculty Publications

Recent advancement in superconducting radio frequency cavity processing techniques, with diffusion of impurities within the RF penetration depth, resulted in high quality factor with increase in quality factor with increasing accelerating gradient. The increase in quality factor is the result of a decrease in the surface resistance as a result of nonmagnetic impurities doping and change in electronic density of states. The fundamental understanding of the dependence of surface resistance on frequency and surface preparation is still an active area of research. Here, we present the result of RF measurements of the TEM modes in a coaxial half-wave niobium cavity ā€¦


Crab Cavities For Ilc, P. A. Mcintosh, S. A. Belomestnykh, G. Burt, R. Calaga, S. U. De Silva, J. R. Delayen, I. V. Gonin, T. N. Khabiboulline, A. Lunin, T. Okugi, Y. M. Orlov, S. VerdĆŗ-AndrĆ©s, B. P. Xiao, V. P. Yakovlev, A. Yamamoto Jan 2023

Crab Cavities For Ilc, P. A. Mcintosh, S. A. Belomestnykh, G. Burt, R. Calaga, S. U. De Silva, J. R. Delayen, I. V. Gonin, T. N. Khabiboulline, A. Lunin, T. Okugi, Y. M. Orlov, S. VerdĆŗ-AndrĆ©s, B. P. Xiao, V. P. Yakovlev, A. Yamamoto

Physics Faculty Publications

For the 14 mrad crossing angle proposed, crab cavity systems are fundamentally anticipated for the viable operation of the International Linear Collider (ILC), in order to maximise its luminosity performance. Since 2021, a specialist development team have been defining optimum crab cavity technologies which can fulfil the operational requirements for ILC, both for its baseline centre-of-mass energy of 250 GeV, but also extending those requirements out to higher beam collision intensities. Five design teams have established crab cavity technology solutions, which have the capability to also operate up to 1 TeV centre-of-mass. This presentation showcases the key performance capabilities of ā€¦


Constraints On The Onset Of Color Transparency From Quasielastic Ā¹Ā²C(E, Eā€²P) Up To QĀ² = (14.2 Gev /C)Ā², D. Bhetuwal, J. Matter, H. Szumila-Vance, C. Ayerbe Gayoso, M. L. Kabir, D. Dutta, R. Ent, D. Abrams, Z. Ahmed, B. Aljawrneh, S. Alsalmi, R. Ambrose, D. Androic, W. Armstrong, A. Asaturyan, K. Assumin-Gyimah, A. Bandari, S. Basnet, V. Berdnikov, J. Zhang, Et Al., Hall C. Collaboration Jan 2023

Constraints On The Onset Of Color Transparency From Quasielastic Ā¹Ā²C(E, Eā€²P) Up To QĀ² = (14.2 Gev /C)Ā², D. Bhetuwal, J. Matter, H. Szumila-Vance, C. Ayerbe Gayoso, M. L. Kabir, D. Dutta, R. Ent, D. Abrams, Z. Ahmed, B. Aljawrneh, S. Alsalmi, R. Ambrose, D. Androic, W. Armstrong, A. Asaturyan, K. Assumin-Gyimah, A. Bandari, S. Basnet, V. Berdnikov, J. Zhang, Et Al., Hall C. Collaboration

Physics Faculty Publications

Quasielastic scattering on 12C(e,eā€²p) was measured in Hall C at Jefferson Lab for spacelike four-momentum transfer squared Q2 in the range of 8ā€“14.2(GeV/c)2 with proton momenta up to 8.3GeV/c. The experiment was carried out in the upgraded Hall C at Jefferson Lab. It used the existing high-momentum spectrometer and the new super-high-momentum spectrometer to detect the scattered electrons and protons in coincidence. The nuclear transparency was extracted as the ratio of the measured yield to the yield calculated in the plane wave impulse approximation. Additionally, the transparency of the 1s1/2 and 1p3/2 shell ā€¦


First Measurement Of The Emc Effect In Ā¹ā°B And Ā¹Ā¹B, A. Karki, D. Biswas, F. A. Gonzalez, W. Henry, C. Morean, A. Nadeeshani, A. Sun, D. Abrams, Z. Ahmed, B. Aljawrneh, S. Alsalmi, R. Ambrose, D. Androic, W. Armstrong, J. Arrington, D. Asaturyan, K. Assumin-Gyimah, C. Ayerbe Gayoso, A. Bandari, J. Zhang, Et Al., Hall C. Collaboration Jan 2023

First Measurement Of The Emc Effect In Ā¹ā°B And Ā¹Ā¹B, A. Karki, D. Biswas, F. A. Gonzalez, W. Henry, C. Morean, A. Nadeeshani, A. Sun, D. Abrams, Z. Ahmed, B. Aljawrneh, S. Alsalmi, R. Ambrose, D. Androic, W. Armstrong, J. Arrington, D. Asaturyan, K. Assumin-Gyimah, C. Ayerbe Gayoso, A. Bandari, J. Zhang, Et Al., Hall C. Collaboration

Physics Faculty Publications

The nuclear dependence of the inclusive inelastic electron scattering cross section (the EMC effect) has been measured for the first time in 10B and 11B. Previous measurements of the EMC effect in A ā‰¤ 12 nuclei showed an unexpected nuclear dependence; 10B and 11B were measured to explore the EMC effect in this region in more detail. Results are presented for 9Be, 10B, 11B, and 12C at an incident beam energy of 10.6 GeV. The EMC effect in the boron isotopes was found to be similar to ā€¦


First Use Of A Longitudinally Polarized Target With Clas12, C. D. Keith, J. Brock, C. Carlin, T. Kageya, V. Lagerquist, J. Maxwell, P. Pandey Jan 2023

First Use Of A Longitudinally Polarized Target With Clas12, C. D. Keith, J. Brock, C. Carlin, T. Kageya, V. Lagerquist, J. Maxwell, P. Pandey

Physics Faculty Publications

Run Group C comprises eight experiments utilizing the CLAS12 detector system in Hall B at Jefferson Lab to study the multidimensional partonic structure of nucleons. The experiments scatter electrons from polarized protons and neutrons in samples of solid NH3 and ND3, dynamically polarized at a temperature of 1 K in a 5 T magnetic field. After a brief description of the target system, the current status of the target and preliminary results of its performance in the experiment are presented.


Measurement Of The Helicity Asymmetry E For The š›¾p ā†’ Pš›‘ā° Reaction In The Resonance Region, C. W. Kim, N. Zachariou, M. Bashkanov, W. J. Briscoe, S. Fegan, V. L. Kashevarov, K. Nikonov, A. Sarantsev, A. Schmidt, I. I. Strakovsky, D. P. Watts, R. L. Workman, P. Achenbach, Z. Akbar, M. J. Amaryan, G. Angelini, W. R. Armstrong, H. Atac, L. Baashen, M. Zurek, Et Al., The Clas Collaboration Jan 2023

Measurement Of The Helicity Asymmetry E For The š›¾p ā†’ Pš›‘ā° Reaction In The Resonance Region, C. W. Kim, N. Zachariou, M. Bashkanov, W. J. Briscoe, S. Fegan, V. L. Kashevarov, K. Nikonov, A. Sarantsev, A. Schmidt, I. I. Strakovsky, D. P. Watts, R. L. Workman, P. Achenbach, Z. Akbar, M. J. Amaryan, G. Angelini, W. R. Armstrong, H. Atac, L. Baashen, M. Zurek, Et Al., The Clas Collaboration

Physics Faculty Publications

The double-spin-polarization observable E for š›¾ā†’ pā†’ ā†’ pš›‘ā° has been measured with the CEBAF Large Acceptance Spectrometer (CLAS) at photon beam energies Eš›¾ from 0.367 to 2.173 GeV (corresponding to center-of-mass energies from 1.240 to 2.200 GeV) for pion center-of-mass angles, cos Īøc.m.š›‘ā°, between - 0.86 and 0.82. These new CLAS measurements cover a broader energy range and have smaller uncertainties compared to previous CBELSA data and provide an important independent check on systematics. These measurements are compared to predictions as well as new global fits from The George Washington University, Mainz, and Bonn-Gatchina ā€¦


Status And Future Plans For CĀ³ R&D, Emilio A. Nanni, Martin Breidenbach, Zenghai Li, Caterina Vernieri, Faya Wang, Glen White, Mei Bai, Sergey Belomestnykh, Pushpalatha Bhat, Tim Barklow, William J. Berg, Valery Borzenets, John Byrd, Ankur Dhar, Ram C. Dhuley, Chris Doss, Joseph Duris, Auralee Edelen, Claudio Emma, Joseph Frisch, Annika Gabriel, Spenser Gessner, Carsten Hast, Chunguang Jing, Arkadiy Klebaner, Dongsung Kim, Anatoly Krasnykh, John Lewellen, Matthias Liepe, Michael Litos, Xueying Lu, Jared Maxon, David Montanari, Pietro Musumeci, Sergei Nagaitsev, Alireza Nassiri, Cho-Kuen Ng, David A. K. Othman, Marco Oriunno, Dennis Palmer, J. Ritchie Patterson, Michael E. Peskin, Thomas J. Peterson, John Power, Ji Qiang, James Rosenzweig, Vladimir Shiltsev, Muhammad Shumail, Evgenya Simakov, Emma Snively, Bruno Spataro, Sami Tantawi, Harry Van Der Graaf, Brandon Weatherford, Juhao Wu, Kent P. Wootton Jan 2023

Status And Future Plans For CĀ³ R&D, Emilio A. Nanni, Martin Breidenbach, Zenghai Li, Caterina Vernieri, Faya Wang, Glen White, Mei Bai, Sergey Belomestnykh, Pushpalatha Bhat, Tim Barklow, William J. Berg, Valery Borzenets, John Byrd, Ankur Dhar, Ram C. Dhuley, Chris Doss, Joseph Duris, Auralee Edelen, Claudio Emma, Joseph Frisch, Annika Gabriel, Spenser Gessner, Carsten Hast, Chunguang Jing, Arkadiy Klebaner, Dongsung Kim, Anatoly Krasnykh, John Lewellen, Matthias Liepe, Michael Litos, Xueying Lu, Jared Maxon, David Montanari, Pietro Musumeci, Sergei Nagaitsev, Alireza Nassiri, Cho-Kuen Ng, David A. K. Othman, Marco Oriunno, Dennis Palmer, J. Ritchie Patterson, Michael E. Peskin, Thomas J. Peterson, John Power, Ji Qiang, James Rosenzweig, Vladimir Shiltsev, Muhammad Shumail, Evgenya Simakov, Emma Snively, Bruno Spataro, Sami Tantawi, Harry Van Der Graaf, Brandon Weatherford, Juhao Wu, Kent P. Wootton

Physics Faculty Publications

C3 is an opportunity to realize an e+e- collider for the study of the Higgs boson at āˆšs = 250 GeV, with a well defined upgrade path to 550 GeV while staying on the same short facility footprint [2,3]. C3 is based on a fundamentally new approach to normal conducting linear accelerators that achieves both high gradient and high efficiency at relatively low cost. Given the advanced state of linear collider designs, the key system that requires technical maturation for C3 is the main linac. This paper presents the staged approach towards a ā€¦


Understanding The Field And Frequency Dependence Of Rf Loss In Srf Cavities, Pashupati Dhakal, G. Ciovati, Alex V. Gurevich, Bashu D. Khanal Jan 2023

Understanding The Field And Frequency Dependence Of Rf Loss In Srf Cavities, Pashupati Dhakal, G. Ciovati, Alex V. Gurevich, Bashu D. Khanal

Physics Faculty Publications

SRF cavities subjected to heat treatment below 200 Ā°C in the presence of nitrogen showed an improvement in quality factor while maintaining an accelerating gradient above 25 MV/m. Here, we report the rf performance of several single-cell superconducting radio frequency cavities with frequency ranging from 0.75 - 3.0 GHz subjected to low temperature heat treatment in nitrogen environment. The cavities were treated at temperature 120 - 175 oC for 24 - 48 hours in low partial pressure of ultra-pure nitrogen gas. The improvement in Qā‚€ with Q-rise was observed when nitrogen gas was injected ~300 Ā°C during the furnace treatment. ā€¦


Numerical Calculations Of Superheating Field In Superconductors With Nanostructured Surfaces, M.R.P. Walive Pathiranage, A. Gurevich Jan 2023

Numerical Calculations Of Superheating Field In Superconductors With Nanostructured Surfaces, M.R.P. Walive Pathiranage, A. Gurevich

Physics Faculty Publications

We reĀ­port calĀ­cuĀ­laĀ­tions of a dc suĀ­perĀ­heatĀ­ing field Hs in suĀ­perĀ­conĀ­ducĀ­tors with nanosĀ­trucĀ­tured surĀ­faces. ParĀ­ticĀ­uĀ­larly, we perĀ­formed nuĀ­merĀ­iĀ­cal simĀ­uĀ­laĀ­tions of the Ginzburg-LanĀ­dau (GL) equaĀ­tions for a suĀ­perĀ­conĀ­ducĀ­tor with an inĀ­hoĀ­moĀ­geĀ­neous proĀ­file of imĀ­puĀ­rity conĀ­cenĀ­traĀ­tion, a thin suĀ­perĀ­conĀ­ductĀ­ing layer on top of anĀ­other suĀ­perĀ­conĀ­ducĀ­tor, and S-I-S mulĀ­tiĀ­layĀ­ers. The suĀ­perĀ­heatĀ­ing field was calĀ­cuĀ­lated takĀ­ing into acĀ­count the inĀ­staĀ­bilĀ­ity of the MeissĀ­ner state at a fiĀ­nite waveĀ­length along the surĀ­face deĀ­pendĀ­ing on the value of the GL paĀ­raĀ­meĀ­ter. SimĀ­uĀ­laĀ­tions were done for the maĀ­teĀ­riĀ­als paĀ­raĀ­meĀ­ters of Nb and Nbā‚ƒSn at difĀ­ferĀ­ent valĀ­ues of the GL paĀ­raĀ­meĀ­ter and the mean free paths. We show ā€¦


Quantum Computations Of The O(3) Model Using Qumodes, R. Jha, Felix Ringer, G. Siopsis, Shane Thompson Jan 2023

Quantum Computations Of The O(3) Model Using Qumodes, R. Jha, Felix Ringer, G. Siopsis, Shane Thompson

Physics Faculty Publications

We express the discrete 1+1-dimensional O(3) non-linear sigma model (NLĻƒM) in a form well-suited for the continuous variable approach to quantum computing. Within the Schwinger boson formulation, we need two qumodes (quantum-mechanical oscillators) at each lattice site. We envision that it might be possible to reach the scaling regime of this model and observe asymptotic freedom on near-term photonic quantum devices in the coming decade.


Covid-19 Crowd Detection, Mustafa Ibrahim, Aly M. Zeineldin, Yameen Khan, Ayman Elmesalami, Soad Ibrahim Jan 2023

Covid-19 Crowd Detection, Mustafa Ibrahim, Aly M. Zeineldin, Yameen Khan, Ayman Elmesalami, Soad Ibrahim

OUR Journal: ODU Undergraduate Research Journal

Object detection was introduced by researchers for face detection. Researchers explain how the detected face is divided into minor frames to be recognized by the algorithm. Due to COVID-19 and government regulations, many people face problems going to shopping centers and shop safely. It has been very hard for both the government and the people to manage social distancing. In our study, we developed a system using Raspberry Pi-4 that will detect the distance between people along with counting the number of distance and mask violations. An error message will appear on the screen in red, showing the total number ā€¦


Analysis Of Ab Initio Protein Structure Prediction Methods, Maytha Alshammari, Jing He Jan 2023

Analysis Of Ab Initio Protein Structure Prediction Methods, Maytha Alshammari, Jing He

College of Sciences Posters

Protein structure prediction produces atomic models of three-dimensional structure of a protein from its amino acid sequence. Understanding the function mechanism of proteins requires knowledge of three-dimensional structures. When developing new enzymes and drugs, it's essential to understand the structure of the target protein. In this study, we analyze models predicted using two ab initio protein structure prediction methods, trRosetta and Quark. A set of thirty protein chains was used to evaluate the effectiveness of the methods. The thirty chains were collected from Protein Data Bank (June ā€“ November, 2020). The length and the relative position of the predicted secondary ā€¦


A Bootstrap Test For Informative Intra-Cluster Group Sizes In Clustered Data, Hasika K. Wickrama Senevirathne, Sandipan Dutta Jan 2023

A Bootstrap Test For Informative Intra-Cluster Group Sizes In Clustered Data, Hasika K. Wickrama Senevirathne, Sandipan Dutta

College of Sciences Posters

Clustered data are frequently observed in various domains of scientific and social studies. In a typical clustered data, units within a cluster are correlated while units between different clusters are independent. An example of such clustered data can be found in dental studies where individuals are treated as clusters and the teeth in an individual are the units within a cluster. While analyzing such clustered data, it has been observed that the number of units present in a cluster can be informative in terms of being associated with the outcome from that cluster. Specifically, when the aim is to compare ā€¦


Hydrodynamics And Sediment Transport In The Tidally Influenced James River, Ollie Gilchrest, Rip Hale Jan 2023

Hydrodynamics And Sediment Transport In The Tidally Influenced James River, Ollie Gilchrest, Rip Hale

The Graduate School Posters

The tidally influenced James River is an important economic, ecologic, and cultural resource for VA residents. Tidal rivers have been historically understudied, however they are critical transition zones, the dynamics of which have implications for freshwater supply and sediment trapping. Globally, estimates suggest that >30% of fluvial sediment is trapped in the tidal zone, the location and dynamics of which are actively changing due to sea level rise and saltwater encroachment. In addition, analysis of historical water levels on the James River has shown a decrease in the tidal range since 1940. The present study combines >1-yearā€™s worth of hydrographic ā€¦


Organic Matter Content And Grain Size Analysis In Seagrass Sediments, Adriana Amrhein, Rip Hale Jan 2023

Organic Matter Content And Grain Size Analysis In Seagrass Sediments, Adriana Amrhein, Rip Hale

College of Sciences Posters

Anthropogenic stresses including increased water temperatures, decreased water quality, sea level rise, ocean acidification and sediment biogeochemical processes have caused a significant loss in seagrass meadow acreage. Seagrass meadows provide coastal protection from storms and recently have been emphasized for their importance in sequestering and storing ā€œBlue Carbonā€ from the atmosphere and ocean. Seagrass meadows can trap this blue carbon in their sediment as organic carbon, and it can be stored for hundreds to thousands of years. Restoration efforts of seagrass meadows in the Virginia coast started in the 1990s and effects of increasing seagrass density can be observed in ā€¦


Dust Deposition To The Bermuda Region: A Comparison Of Estimates Using Seasonally-Resolved Measurements Of Aluminum In Water-Column, Aerosol, And Rain Samples, Tara Williams, Peter Sedwick, Bettina Sohst, Joe Resing, Kristen Buck, Salvatore Caprara, Rod Johnson, Dan Ohnemus, Ben Twining, Alessandro Tagliabue Jan 2023

Dust Deposition To The Bermuda Region: A Comparison Of Estimates Using Seasonally-Resolved Measurements Of Aluminum In Water-Column, Aerosol, And Rain Samples, Tara Williams, Peter Sedwick, Bettina Sohst, Joe Resing, Kristen Buck, Salvatore Caprara, Rod Johnson, Dan Ohnemus, Ben Twining, Alessandro Tagliabue

College of Sciences Posters

Dust deposition is a major source of bioactive trace elements to the surface ocean, yet this flux remains difficult to constrain. Previously, time-averaged dust flux has been estimated using surface ocean dissolved aluminum (DAl) concentrations, assumed values for aerosol aluminum solubility (%AlS), and the residence time of DAl in the surface mixed layer (SML). We apply this method to estimate dust deposition in the Bermuda Atlantic Time-series Study (BATS) region using water-column DAl data from cruises in 2019, which is compared with direct flux estimates from contemporaneous measurements of aluminum in aerosols and rain collected on Bermuda. Seasonal ā€¦


Acceleration Of U.S. Southeast And Gulf Coast Sea-Level Rise Amplified By Internal Climate Variability, Sƶnke Dangendorf, Noah Hendricks, Qiang Sun, John Klinck, Tal Ezer, Thomas Frederikse, Francisco M. Calafat, Thomas Wahl, Torbjƶrn E. Tƶrnqvist Jan 2023

Acceleration Of U.S. Southeast And Gulf Coast Sea-Level Rise Amplified By Internal Climate Variability, Sƶnke Dangendorf, Noah Hendricks, Qiang Sun, John Klinck, Tal Ezer, Thomas Frederikse, Francisco M. Calafat, Thomas Wahl, Torbjƶrn E. Tƶrnqvist

CCPO Publications

While there is evidence for an acceleration in global mean sea level (MSL) since the 1960s, its detection at local levels has been hampered by the considerable influence of natural variability on the rate of MSL change. Here we report a MSL acceleration in tide gauge records along the U.S. Southeast and Gulf coasts that has led to rates (>10ā€‰mmā€‰yrāˆ’1 since 2010) that are unprecedented in at least 120 years. We show that this acceleration is primarily induced by an ocean dynamic signal exceeding the externally forced response from historical climate model simulations. However, when the ā€¦


Autodesc: Facilitating Convenient Perusal Of Web Data Items For Blind Users, Yash Prakash, Mohan Sunkara, Hae-Na Lee, Sampath Jayarathna, Vikas Ashok Jan 2023

Autodesc: Facilitating Convenient Perusal Of Web Data Items For Blind Users, Yash Prakash, Mohan Sunkara, Hae-Na Lee, Sampath Jayarathna, Vikas Ashok

Computer Science Faculty Publications

Web data items such as shopping products, classifieds, and job listings are indispensable components of most e-commerce websites. The information on the data items are typically distributed over two or more webpages, e.g., a ā€˜Query-Resultsā€™ page showing the summaries of the items, and ā€˜Detailsā€™ pages containing full information about the items. While this organization of data mitigates information overload and visual cluttering for sighted users, it however increases the interaction overhead and effort for blind users, as back-and-forth navigation between webpages using screen reader assistive technology is tedious and cumbersome. Existing usability-enhancing solutions are unable to provide adequate support in ā€¦


Intergenic Transcription In In Vivo Developed Bovine Oocytes And Pre-Implantation Embryos, Saurav Ranjitkar, Mohammad Shiri, Jiangwen Sun, Xiuchun Tian Jan 2023

Intergenic Transcription In In Vivo Developed Bovine Oocytes And Pre-Implantation Embryos, Saurav Ranjitkar, Mohammad Shiri, Jiangwen Sun, Xiuchun Tian

Computer Science Faculty Publications

Background

Intergenic transcription, either failure to terminate at the transcription end site (TES), or transcription initiation at other intergenic regions, is present in cultured cells and enhanced in the presence of stressors such as viral infection. Transcription termination failure has not been characterized in natural biological samples such as pre-implantation embryos which express more than 10,000 genes and undergo drastic changes in DNA methylation.

Results

Using Automatic Readthrough Transcription Detection (ARTDeco) and data of in vivo developed bovine oocytes and embryos, we found abundant intergenic transcripts that we termed as read-outs (transcribed from 5 to 15 kb after TES) and ā€¦


Numerical Study Of Sediment Suspension Affected By Rigid Cylinders Under Unidirectional And Combined Wave-Current Flows, Sha Lou, Xiaolan Chen, Shengyu Zhou, Gangfeng Ma, Shuguang Liu, Larisa Dorzhievna Radnaeva, Elena Nikitina, Irina Viktorovna Fedorova Jan 2023

Numerical Study Of Sediment Suspension Affected By Rigid Cylinders Under Unidirectional And Combined Wave-Current Flows, Sha Lou, Xiaolan Chen, Shengyu Zhou, Gangfeng Ma, Shuguang Liu, Larisa Dorzhievna Radnaeva, Elena Nikitina, Irina Viktorovna Fedorova

Civil & Environmental Engineering Faculty Publications

Sediment transport modeling for flows with cylinders is very challenging owing to the complicated flowā€“cylinderā€“sediment interactions, especially under the combined wave-current flows. In this paper, an improved formulation for incipient sediment suspension considering the effect of cylinder density (i.e., solid volume fraction) is employed to simulate the bottom sediment flux in the flow with cylinders. The proposed model is calibrated and validated using laboratory measurements under unidirectional and combined wave-current flows in previous studies. It is proved that the effects of cylinders on sediment suspension can be accounted for through a modified critical Shields number, and the proposed model is ā€¦