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Articles 1801 - 1830 of 5954

Full-Text Articles in Physical Sciences and Mathematics

First Measurement Of Near-Threshold J/ᴪ Exclusive Photoproduction Off The Proton, M. Ali, M. Amaryan, E.G. Anassontzis, Q. Zhou, X. Zhou, B. Zihlmann, Gluex Collaboration Jan 2019

First Measurement Of Near-Threshold J/ᴪ Exclusive Photoproduction Off The Proton, M. Ali, M. Amaryan, E.G. Anassontzis, Q. Zhou, X. Zhou, B. Zihlmann, Gluex Collaboration

Physics Faculty Publications

We report on the measurement of the γp -> J/ψp cross section from Eγ = 11.8 GeV down to the threshold at 8.2 GeV using a tagged photon beam with the GlueX experiment. We find that the total cross section falls toward the threshold less steeply than expected from two-gluon exchange models. The differential cross section dσ/dt has an exponential slope of 1.67 ± 0.39 GeV-2 at 10.7 GeV average energy. The LHCb pentaquark candidates P+c can be produced in the s channel of this reaction. We see no evidence for them and set model-dependent upper …

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Finite Volume Matrix Elements Of Two-Body States, Alessandro Baroni, Raúl A. Briceño, Maxwell T. Hansen, Filipe G. Ortega-Gama Jan 2019

Finite Volume Matrix Elements Of Two-Body States, Alessandro Baroni, Raúl A. Briceño, Maxwell T. Hansen, Filipe G. Ortega-Gama

Physics Faculty Publications

In this talk, we present a framework for studying structural information of resonances and bound states coupling to two-hadron scattering states. This makes use of a recently proposed finite-volume formalism to determine a class of observables that are experimentally inaccessible but can be accessed via lattice QCD. In particular, we shown that finite-volume two-body matrix elements with one current insertion can be directly related to scattering amplitudes coupling to the external current. For two-hadron systems with resonances or bound states, one can extract the corresponding form factors of these from the energy-dependence of the amplitudes.

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Recent Results From Nb₃Sn Single Cell Cavities Coated At Jefferson Lab, U. Pudasaini, M. J. Kelley, Gianluigi Ciovati, G.V. Eremeev, M. J. Kelley, C. E. Reece, Ishwari Prasad Parajuli, Md. Nizam Sayeed Jan 2019

Recent Results From Nb₃Sn Single Cell Cavities Coated At Jefferson Lab, U. Pudasaini, M. J. Kelley, Gianluigi Ciovati, G.V. Eremeev, M. J. Kelley, C. E. Reece, Ishwari Prasad Parajuli, Md. Nizam Sayeed

Physics Faculty Publications

Because of superior superconducting properties (Tc ~ 18.3K, Hs h~ 425 mT and Δ ~ 3.1 meV) compared to niobium, Nb₃Sn promise better RF performance (Q₀ and Eacc) and/or higher operating temperature (2 K Vs 4.2 K) for SRF cavities. Nb₃Sn-coated SRF cavities are produced routinely by depositing a few micron-thick Nb₃Sn films on the interior surface of Nb cavities via tin vapor diffusion technique. Early results from Nb₃Sn cavities coated with this technique exhibited precipitous low field Q-slope, also known as Wuppertal slope. Several Nb₃Sn single cell cavities coated at JLab appeared to exhibit …

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A Multi-Layered Srf Cavity For Conduction Cooling Applications, Gianluigi Ciovati, G. Cheng, E. Daly, G. V. Eremeev, J. Henry, R. A. Rimmer, Ishwari Prasad Parajuli, U. Pudasaini Jan 2019

A Multi-Layered Srf Cavity For Conduction Cooling Applications, Gianluigi Ciovati, G. Cheng, E. Daly, G. V. Eremeev, J. Henry, R. A. Rimmer, Ishwari Prasad Parajuli, U. Pudasaini

Physics Faculty Publications

Industrial application of SRF technology would favor the use of cryocoolers to conductively cool SRF cavities for particle accelerators, operating at or above 4.3 K. In order to achieve a lower surface resistance than Nb at 4.3 K, a superconductor with higher critical temperature should be used, whereas a metal with higher thermal conductivity than Nb should be used to conduct the heat to the cryocoolers. A standard 1.5 GHz bulk Nb single-cell cavity has been coated with a ~2 µm thick layer of Nb₃Sn on the inner surface and with a 5 mm thick Cu layer on the outer …

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The Us Electron Ion Collider Accelerator Designs, A. Seryi, S.V. Benson, S.A. Bogacz, P.D. Brindza, M.W. Brucker, A. Camsonne, E. Daly, P.V. Degtiarenko, Y.S. Derbenev, M. Diefenthaler, J. Dolbeck, R. Ent, R. Fair, D. Fazenbaker, Y. Furletova, B.R. Gamage, D. Gaskell, R.L. Geng, P. Ghoshal, R.C. York, Et Al. Jan 2019

The Us Electron Ion Collider Accelerator Designs, A. Seryi, S.V. Benson, S.A. Bogacz, P.D. Brindza, M.W. Brucker, A. Camsonne, E. Daly, P.V. Degtiarenko, Y.S. Derbenev, M. Diefenthaler, J. Dolbeck, R. Ent, R. Fair, D. Fazenbaker, Y. Furletova, B.R. Gamage, D. Gaskell, R.L. Geng, P. Ghoshal, R.C. York, Et Al.

Physics Faculty Publications

With the completion of the National Academies of Sciences Assessment of a US Electron-Ion Collider, the prospects for construction of such a facility have taken a step forward. This paper provides an overview of the two site-specific EIC designs: JLEIC (Jefferson Lab) and eRHIC (BNL) as well as brief overview of ongoing EIC R&D.

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Finite Volume Matrix Elements Of Two-Body States With One Current Insertion, Alessandro Baroni, Raúl Briceño, Maxwell Hansen, Felipe Ortega Jan 2019

Finite Volume Matrix Elements Of Two-Body States With One Current Insertion, Alessandro Baroni, Raúl Briceño, Maxwell Hansen, Felipe Ortega

Physics Faculty Publications

No abstract provided.

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Analysis Of Higher Order Multipoles Of The 952.6 Mhz Rf-Dipole Crabbing Cavity For The Jefferson Lab Electron Ion Collider, Subashini U. De Silva, J. R. Delayen, V. S. Morozov, H. Park, S. Sosa Jan 2019

Analysis Of Higher Order Multipoles Of The 952.6 Mhz Rf-Dipole Crabbing Cavity For The Jefferson Lab Electron Ion Collider, Subashini U. De Silva, J. R. Delayen, V. S. Morozov, H. Park, S. Sosa

Physics Faculty Publications

The crabbing system is a key feature in the Jefferson Lab Electron-Ion Collider (JLEIC) required to increase the luminosity of the colliding bunches. A local crabbing system will be installed with superconducting rf-dipole crabbing cavities operating at 952.6 MHz. The field non-uniformity across the beam aperture in the crabbing cavities produces higher order multipole components, similar to that which are present in magnets. Knowledge of higher order mode multipole field effects is important for accurate beam dynamics study for the crabbing system. In this paper, we quantify the multipole components and analyse their effects on the beam dynamics.

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New Simulations For Ion-Production And Back-Bombardment In Gaas Photo-Guns, Josh Yoskowitz, J. Grames, J. Hansknecht, C. Hernandez-Garcia, G. Krafft, M. Poelker, R. Suleiman, G. Palacios-Seranno, S. Wijethunga, B. Van Der Geer Jan 2019

New Simulations For Ion-Production And Back-Bombardment In Gaas Photo-Guns, Josh Yoskowitz, J. Grames, J. Hansknecht, C. Hernandez-Garcia, G. Krafft, M. Poelker, R. Suleiman, G. Palacios-Seranno, S. Wijethunga, B. Van Der Geer

Physics Faculty Publications

GaAs-based DC high voltage photo-guns used at accelerators with extensive user programs must exhibit long photocathode operating lifetime. Achieving this goal represents a significant challenge for proposed high average current facilities that must operate at tens of milliamperes or more. Specifically, the operating lifetime is dominated by ion back-bombardment of the photocathode from ionized residual gas. While numerous experiments have been performed to characterize the operating lifetime under various conditions, detailed simulations of the ion back-bombardment mechanism that explains these experiments are lacking. Recently, a new user routine was implemented using the code General Particle Tracer (GPT) to simulate electron …

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Transfer Learning For Detecting Unknown Network Attacks, Juan Zhao, Sachin Shetty, Jan Wei Pan, Charles Kamhoua, Kevin Kwiat Jan 2019

Transfer Learning For Detecting Unknown Network Attacks, Juan Zhao, Sachin Shetty, Jan Wei Pan, Charles Kamhoua, Kevin Kwiat

VMASC Publications

Network attacks are serious concerns in today’s increasingly interconnected society. Recent studies have applied conventional machine learning to network attack detection by learning the patterns of the network behaviors and training a classification model. These models usually require large labeled datasets; however, the rapid pace and unpredictability of cyber attacks make this labeling impossible in real time. To address these problems, we proposed utilizing transfer learning for detecting new and unseen attacks by transferring the knowledge of the known attacks. In our previous work, we have proposed a transfer learning-enabled framework and approach, called HeTL, which can find the common …

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Dimensionality And Factorial Invariance Of Religiosity Among Christians And The Religiously Unaffiliated: A Cross-Cultural Analysis Based On The International Social Survey Programme, Carlos Miguel Lemos, Ross Joseph Gore, Ivan Puga-Gonzalez, F. Leron Shults Jan 2019

Dimensionality And Factorial Invariance Of Religiosity Among Christians And The Religiously Unaffiliated: A Cross-Cultural Analysis Based On The International Social Survey Programme, Carlos Miguel Lemos, Ross Joseph Gore, Ivan Puga-Gonzalez, F. Leron Shults

VMASC Publications

We present a study of the dimensionality and factorial invariance of religiosity for 26 countries with a Christian heritage, based on the 1998 and 2008 rounds of the International Social Survey Programme (ISSP) Religion survey, using both exploratory and multi-group confirmatory factor analyses. The results of the exploratory factor analysis showed that three factors, common to Christian and religiously unaffiliated respondents, could be extracted from our initially selected items and suggested the testing of four different three-factor models using multi-group confirmatory factor analysis. For the model with the best fit and measurement invariance properties, we labeled the three resulting factors …

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Hurricane Model Development At Gfdl: A Collaborative Success Story From A Historical Perspective, Morris A. Bender, Timothy Marchok, Robert E. Tuleya, Isaac Ginis, Vijay Tallapragada, Stephen J. Lord Jan 2019

Hurricane Model Development At Gfdl: A Collaborative Success Story From A Historical Perspective, Morris A. Bender, Timothy Marchok, Robert E. Tuleya, Isaac Ginis, Vijay Tallapragada, Stephen J. Lord

CCPO Publications

The hurricane project at the National Oceanic and Atmospheric Administration (NOAA) Geophysical Fluid Dynamics Laboratory (GFDL) was established in 1970. By the mid-1970s pioneering research had led to the development of a new hurricane model. As the reputation of the model grew, GFDL was approached in 1986 by the director of the National Meteorological Center about establishing a collaboration between the two federal organizations to transition the model into an operational modeling system. After a multiyear effort by GFDL scientists to develop a system that could support rigorous requirements of operations, and multiyear testing had demonstrated its superior performance compared …

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Modeling Ocean Eddies On Antarctica's Cold Water Continental Shelves And Their Effects On Ice Shelf Basal Melting, Stefanie L. Mack, Michael S. Dinniman, John M. Klinck, Dennis J. Mcgillicuddy, Laurence Padman Jan 2019

Modeling Ocean Eddies On Antarctica's Cold Water Continental Shelves And Their Effects On Ice Shelf Basal Melting, Stefanie L. Mack, Michael S. Dinniman, John M. Klinck, Dennis J. Mcgillicuddy, Laurence Padman

CCPO Publications

Changes in the rate of ocean‐driven basal melting of Antarctica's ice shelves can alter the rate at which the grounded ice sheet loses mass and contributes to sea level change. Melt rates depend on the inflow of ocean heat, which occurs through steady circulation and eddy fluxes. Previous studies have demonstrated the importance of eddy fluxes for ice shelves affected by relatively warm intrusions of Circumpolar Deep Water. However, ice shelves on cold water continental shelves primarily melt from dense shelf water near the grounding line and from light surface water at the ice shelf front. Eddy effects on basal …

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Delivering Sustained, Coordinated, And Integrated Observations Of The Southern Ocean For Global Impact, Louise Newman, Petra Heil, Rowan Tebilco, Katsuro Katsumata, Andrew Constable, Esmee Van Wijk, Karen Assmann, Joana Beja, Phillippa Bricher, Richard Coleman, Daniel Costa, Steve Diggs, Riccardo Farneti, Sarah Fawcett, Sarah T. Gille, Katharine R. Hendry, Sian Henly, Eileen Hofmann, Ted Maksym, Matthew Mazloff, Andrew Meijers, Michael M. Meredith, Sebastien Moreau, Burcu Ozsoy, Robin Robertson, Irene Schloss, Oscar Schofield, Jiuxin Shi, Elisabeth Sikes, Inga J. Smith, Sebastiaan Swart, Anna Wahlin, Guy Williams, Michael J. M. Williams, Laura Herraiz-Borreguero, Stefan Kern, Jan Lieser, Robert A. Massom, Jessica Melbourne-Thomas, Patricia Miloslavich, Gunnar Spreen Jan 2019

Delivering Sustained, Coordinated, And Integrated Observations Of The Southern Ocean For Global Impact, Louise Newman, Petra Heil, Rowan Tebilco, Katsuro Katsumata, Andrew Constable, Esmee Van Wijk, Karen Assmann, Joana Beja, Phillippa Bricher, Richard Coleman, Daniel Costa, Steve Diggs, Riccardo Farneti, Sarah Fawcett, Sarah T. Gille, Katharine R. Hendry, Sian Henly, Eileen Hofmann, Ted Maksym, Matthew Mazloff, Andrew Meijers, Michael M. Meredith, Sebastien Moreau, Burcu Ozsoy, Robin Robertson, Irene Schloss, Oscar Schofield, Jiuxin Shi, Elisabeth Sikes, Inga J. Smith, Sebastiaan Swart, Anna Wahlin, Guy Williams, Michael J. M. Williams, Laura Herraiz-Borreguero, Stefan Kern, Jan Lieser, Robert A. Massom, Jessica Melbourne-Thomas, Patricia Miloslavich, Gunnar Spreen

CCPO Publications

The Southern Ocean is disproportionately important in its effect on the Earth system, impacting climatic, biogeochemical, and ecological systems, which makes recent observed changes to this system cause for global concern. The enhanced understanding and improvements in predictive skill needed for understanding and projecting future states of the Southern Ocean require sustained observations. Over the last decade, the Southern Ocean Observing System (SOOS) has established networks for enhancing regional coordination and research community groups to advance development of observing system capabilities. These networks support delivery of the SOOS 20-year vision, which is to develop a circumpolar system that ensures time …

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Management Strategy Evaluation: Transdisciplinary And Transparent Natural Resource Management, Eileen Hofmann, Lisa Maddison, Ingrid Van Putten Jan 2019

Management Strategy Evaluation: Transdisciplinary And Transparent Natural Resource Management, Eileen Hofmann, Lisa Maddison, Ingrid Van Putten

CCPO Publications

Management Strategy Evaluation (MSE) is a modelling tool used to evaluate sufficiently realistic simulations of potential policy choices in complex systems. As a contribution to the Integrated Marine Biosphere Research (IMBeR) project IMBIZO V, which occurred in October 2017, a workshop was convened with the goal of developing a coherent understanding of best-practice approaches for MSEs. MSEs are becoming standard approaches to characterizing risk across fisheries management organizations globally. MSEs are important tools that aid in delineating objectives, costs, and constraints that define risk and provide a possible mechanism to meet assessment challenges. The MSE workshop considered case studies drawn …

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Odu Receives $3 Million For Resilience From Philanthropist Joan Brock, Noell Saunders Jan 2019

Odu Receives $3 Million For Resilience From Philanthropist Joan Brock, Noell Saunders

News Items

No abstract provided.

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Quantifying The Concentration And Penetration Depth Of Long-Lived Rons In Plasma Activated Water By Uv Absorption Spectroscopy, Zhijie Liu, Chunxi Zhou, Dingxin Liu, Tongtong He, Li Guo, Dehui Xu, Michael G. Kong Jan 2019

Quantifying The Concentration And Penetration Depth Of Long-Lived Rons In Plasma Activated Water By Uv Absorption Spectroscopy, Zhijie Liu, Chunxi Zhou, Dingxin Liu, Tongtong He, Li Guo, Dehui Xu, Michael G. Kong

Bioelectrics Publications

Reactive oxygen and reactive nitrogen species (RONS) are believed to play a key role in biomedical applications, which means that RONS must reach the target tissue to produce a therapeutic effect. Existing methods (electron spin spectrometry and microplate reading) to determine the RONS concentration are not suitable for experimental real-time measurements because they require adding an indicating reagent to the plasma-treated medium, which may alter the chemical composition of the medium. In this paper, we propose a method to measure the long-lived RONS concentration in plasma-activated water (PAW) by using UV absorption spectroscopy. Based on an analysis and fit of …

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Observations And Scaling Of Tidal Mass Transport Across The Lower Ganges-Brahmaputra Delta Plain: Implications For Delta Management And Sustainability, Richard Hale, Rachel Bain, Steven Goodbred Jr., Jim Best Jan 2019

Observations And Scaling Of Tidal Mass Transport Across The Lower Ganges-Brahmaputra Delta Plain: Implications For Delta Management And Sustainability, Richard Hale, Rachel Bain, Steven Goodbred Jr., Jim Best

OES Faculty Publications

The landscape of southwest Bangladesh, a region constructed primarily by fluvial processes associated with the Ganges River and Brahmaputra River, is now maintained almost exclusively by tidal processes as the fluvial system has migrated east and eliminated the most direct fluvial input. In natural areas such as the Sundarbans National Forest, year-round inundation during spring high tides delivers sufficient sediment that enables vertical accretion to keep pace with relative sea-level rise. However, recent human modification of the landscape in the form of embankment construction has terminated this pathway of sediment delivery for much of the region, resulting in a startling …

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The Mortality Response To Absolute And Relative Temperature Extremes, Scott C. Sheridan, Cameron C. Lee, Michael J. Allen Jan 2019

The Mortality Response To Absolute And Relative Temperature Extremes, Scott C. Sheridan, Cameron C. Lee, Michael J. Allen

Political Science & Geography Faculty Publications

While the impact of absolute extreme temperatures on human health has been amply studied, far less attention has been given to relative temperature extremes, that is, events that are highly unusual for the time of year but not necessarily extreme relative to a location's overall climate. In this research, we use a recently defined extreme temperature event metric to define absolute extreme heat events (EHE) and extreme cold events (ECE) using absolute thresholds, and relative extreme heat events (REHE) and relative extreme cold events (RECE) using relative thresholds. All-cause mortality outcomes using a distributed lag nonlinear model are evaluated for …

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Reimagining Medical Education In The Age Of Ai, Steven A. Wartman, C. Donald Combs Jan 2019

Reimagining Medical Education In The Age Of Ai, Steven A. Wartman, C. Donald Combs

Computational Modeling & Simulation Engineering Faculty Publications

Available medical knowledge exceeds the organizing capacity of the human mind, yet medical education remains based on information acquisition and application. Complicating this information overload crisis among learners is the fact that physicians' skill sets now must include collaborating with and managing artificial intelligence (AI) applications that aggregate big data, generate diagnostic and treatment recommendations, and assign confidence ratings to those recommendations. Thus, an overhaul of medical school curricula is due and should focus on knowledge management (rather than information acquisition), effective use of AI, improved communication, and empathy cultivation.

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Change Detection Using Landsat And Worldview Images, Chiman Kwan, Bryan Chou, Leif Hagen, Daniel Perez, Yuzhong Shen, Jiang Li, Krzysztof Koperski Jan 2019

Change Detection Using Landsat And Worldview Images, Chiman Kwan, Bryan Chou, Leif Hagen, Daniel Perez, Yuzhong Shen, Jiang Li, Krzysztof Koperski

Computational Modeling & Simulation Engineering Faculty Publications

This paper presents some preliminary results using Landsat and Worldview images for change detection. The studied area had some significant changes such as construction of buildings between May 2014 and October 2015. We investigated several simple, practical, and effective approaches to change detection. For Landsat images, we first performed pansharpening to enhance the resolution to 15 meters. We then performed a chronochrome covariance equalization between two images. The residual between the two equalized images was then analyzed using several simple algorithms such as direct subtraction and global Reed-Xiaoli (GRX) detector. Experimental results using actual Landsat images clearly demonstrated that the …

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Fusion Of Landsat And Worldview Images, Chiman Kwan, Bryan Chou, Jerry Yang, Daniel Perez, Yuzhong Shen, Jiang Li, Krzysztof Koperski Jan 2019

Fusion Of Landsat And Worldview Images, Chiman Kwan, Bryan Chou, Jerry Yang, Daniel Perez, Yuzhong Shen, Jiang Li, Krzysztof Koperski

Computational Modeling & Simulation Engineering Faculty Publications

Pansharpened Landsat images have 15 m spatial resolution with 16-day revisit periods. On the other hand, Worldview images have 0.5 m resolution after pansharpening but the revisit times are uncertain. We present some preliminary results for a challenging image fusion problem that fuses Landsat and Worldview (WV) images to yield a high temporal resolution image sequence at the same spatial resolution of WV images. Since the spatial resolution between Landsat and Worldview is 30 to 1, our preliminary results are mixed in that the objective performance metrics such as peak signal-to-noise ratio (PSNR), correlation coefficient (CC), etc. sometimes showed good …

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Emerging Roles Of Virtual Patients In The Age Of Ai, C. Donald Combs, P. Ford Combs Jan 2019

Emerging Roles Of Virtual Patients In The Age Of Ai, C. Donald Combs, P. Ford Combs

Computational Modeling & Simulation Engineering Faculty Publications

Today's web-enabled and virtual approach to medical education is different from the 20th century's Flexner-dominated approach. Now, lectures get less emphasis and more emphasis is placed on learning via early clinical exposure, standardized patients, and other simulations. This article reviews literature on virtual patients (VPs) and their underlying virtual reality technology, examines VPs' potential through the example of psychiatric intake teaching, and identifies promises and perils posed by VP use in medical education.

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Tsunamigenic Potential Of The Baiyun Slide Complex In The South China Sea, Linlin Li, Fengyan Shi, Gangfeng Ma, Qiang Qiu Jan 2019

Tsunamigenic Potential Of The Baiyun Slide Complex In The South China Sea, Linlin Li, Fengyan Shi, Gangfeng Ma, Qiang Qiu

Civil & Environmental Engineering Faculty Publications

The Baiyun slide complex contains geological evidence for some of the largest landslide ever discovered in the continental slopes of the South China Sea. High-resolution seismic data suggest that a variety of landslides with varied scales have occurred repeatedly in this area. The largest landslide reconstructed from bathymetric and seismic data has an estimated spatial coverage of ~5,500 km2 and a conservative volume of ~1,035 km3. Here, using geomorphological and geotechnical data, we construct a series of probable landslide scenarios and assess their tsunamigenic capacity. By treating the slides as deformable mudflows, we simulate the dynamics of …

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Attacker Capability Based Dynamic Deception Model For Large-Scale Networks, Md Ali Reza Al Amin, Sachhin Shetty, Laurent Njilla, Deepak K. Tosh, Charles Kamhoua Jan 2019

Attacker Capability Based Dynamic Deception Model For Large-Scale Networks, Md Ali Reza Al Amin, Sachhin Shetty, Laurent Njilla, Deepak K. Tosh, Charles Kamhoua

Computational Modeling & Simulation Engineering Faculty Publications

In modern days, cyber networks need continuous monitoring to keep the network secure and available to legitimate users. Cyber attackers use reconnaissance mission to collect critical network information and using that information, they make an advanced level cyber-attack plan. To thwart the reconnaissance mission and counterattack plan, the cyber defender needs to come up with a state-of-the-art cyber defense strategy. In this paper, we model a dynamic deception system (DDS) which will not only thwart reconnaissance mission but also steer the attacker towards fake network to achieve a fake goal state. In our model, we also capture the attacker’s capability …

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Experimental Verification Of Transparent Spin Mode In Rhic, V. S. Morozov, P. Adams, Y. S. Derbenev, Y. Filatov, H. Huang, A. M. Kondratenko, M. A. Kondratenko, F. Lin, F. Méot, V. Ptitsyn, W. B. Schmidke, Y. Zhang Jan 2019

Experimental Verification Of Transparent Spin Mode In Rhic, V. S. Morozov, P. Adams, Y. S. Derbenev, Y. Filatov, H. Huang, A. M. Kondratenko, M. A. Kondratenko, F. Lin, F. Méot, V. Ptitsyn, W. B. Schmidke, Y. Zhang

Engineering Technology Faculty Publications

High electron and ion polarizations are some of the key design requirements of a future Electron Ion Collider (EIC). The transparent spin mode, a concept inspired by the figure 8 ring design of JLEIC, is a novel technique for preservation and control of electron and ion spin polarizations in a collider or storage ring. It makes the ring lattice "invisible" to the spin and allows for polarization control by small quasi-static magnetic fields with practically no effect on the beam’s orbital characteristics. It offers unique opportunities for polarization maintenance and control in Jefferson Lab’s JLEIC and in BNL’s eRHIC. The …

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Sponges Structure Water-Column Characteristics In Shallow Tropical Coastal Ecosystems, Marla M. Valentine, Mark J. Butler Iv Jan 2019

Sponges Structure Water-Column Characteristics In Shallow Tropical Coastal Ecosystems, Marla M. Valentine, Mark J. Butler Iv

Biological Sciences Faculty Publications

Sponges can have powerful effects on ecosystem processes in shallow tropical marine ecosystems. They drive benthic-pelagic coupling by filtering dissolved and particulate organic matter from the water column, alter water chemistry in association with their symbiotic microorganisms, and increase habitat structural complexity. Anthropogenic degradation of coastal waters is widespread and can reduce the density and diversity of foundation species such as sponges, potentially diminishing their contributions to ecosystem processes. We used a novel mesocosm design that minimized artifacts associated with traditional single-species and closed-system filtration experiments to examine the effects of water turnover and sponge biomass on water-column properties. Using …

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Ebullition Of Oxygen From Seagrasses Under Supersaturated Conditions, Matthew H. Long, Kevin Sutherland, Scott D. Wankel, David J. Burdige, Richard C. Zimmerman Jan 2019

Ebullition Of Oxygen From Seagrasses Under Supersaturated Conditions, Matthew H. Long, Kevin Sutherland, Scott D. Wankel, David J. Burdige, Richard C. Zimmerman

OES Faculty Publications

Gas ebullition from aquatic systems to the atmosphere represents a potentially important fraction of primary production that goes unquantified by measurements of dissolved gas concentrations. Although gas ebullition from photosynthetic surfaces has often been observed, it is rarely quantified. The resulting underestimation of photosynthetic activity may significantly bias the determination of ecosystem trophic status and estimated rates of biogeochemical cycling from in situ measures of dissolved oxygen. Here, we quantified gas ebullition rates in Zostera marina meadows in Virginia, U.S.A. using simple funnel traps and analyzed the oxygen concentration and isotopic composition of the captured gas. Maximum hourly rates of …

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Metaproteomics Reveal That Rapid Perturbations In Organic Matter Prioritize Functional Restructuring Over Taxonomy In Western Arctic Ocean Microbiomes, Molly P. Mikan, H. Rodger Harvey, Emma Timmins-Schiffman, Michael Riffle, Damon H. May, Ian Salter, William S. Noble, Brook L. Nunn Jan 2019

Metaproteomics Reveal That Rapid Perturbations In Organic Matter Prioritize Functional Restructuring Over Taxonomy In Western Arctic Ocean Microbiomes, Molly P. Mikan, H. Rodger Harvey, Emma Timmins-Schiffman, Michael Riffle, Damon H. May, Ian Salter, William S. Noble, Brook L. Nunn

OES Faculty Publications

We examined metaproteome profiles from two Arctic microbiomes during 10-day shipboard incubations to directly track early functional and taxonomic responses to a simulated algal bloom and an oligotrophic control. Using a novel peptide-based enrichment analysis, significant changes (p-value < 0.01) in biological and molecular functions associated with carbon and nitrogen recycling were observed. Within the first day under both organic matter conditions, Bering Strait surface microbiomes increased protein synthesis, carbohydrate degradation, and cellular redox processes while decreasing C1 metabolism. Taxonomic assignments revealed that the core microbiome collectively responded to algal substrates by assimilating carbon before select taxa utilize and metabolize nitrogen intracellularly. Incubations of Chukchi Sea bottom water microbiomes showed similar, but delayed functional responses to identical treatments. Although 24 functional terms were shared between experimental treatments, the timing, and degree of the remaining responses were highly variable, showing that organic matter perturbation directs community functionality prior to alterations to the taxonomic distribution at the microbiome class level. The dynamic responses of these two oceanic microbial communities have important implications for timing and magnitude of responses to organic perturbations within the Arctic Ocean and how community-level functions may forecast biogeochemical gradients in oceans.

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Internal Waves Influence The Thermal And Nutrient Environment On A Shallow Coral Reef, Emma C. Reid, Thomas M. Decarlo, Anne L. Cohen, George T.F. Wong, Steven J. Lentz, Aryan Safaie, Austin Hall, Kristen A. Davis Jan 2019

Internal Waves Influence The Thermal And Nutrient Environment On A Shallow Coral Reef, Emma C. Reid, Thomas M. Decarlo, Anne L. Cohen, George T.F. Wong, Steven J. Lentz, Aryan Safaie, Austin Hall, Kristen A. Davis

OES Faculty Publications

Internal waves can influence water properties in coastal ecosystems through the shoreward transport and mixing of subthermocline water into the nearshore region. In June 2014, a field experiment was conducted at Dongsha Atoll in the northern South China Sea to study the impact of internal waves on a coral reef. Instrumentation included a distributed temperature sensing system, which resolved spatially and temporally continuous temperature measurements over a 4‐km cross‐reef section from the lagoon to 50‐m depth on the fore reef. Our observations show that during summer, internal waves shoaling on the shallow atoll regularly transport cold, nutrient‐rich water shoreward, altering …

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Automatic Detection And Analysis Of Rip Currents At Haeundae Beach Using X-Band Marine Radar, Chanyeong Oh, Kyungmo Ahn, Se-Hyeon Cheon Jan 2019

Automatic Detection And Analysis Of Rip Currents At Haeundae Beach Using X-Band Marine Radar, Chanyeong Oh, Kyungmo Ahn, Se-Hyeon Cheon

OES Faculty Publications

The observation system has been developed to investigate the rip currents at Haeundae beach using Xband marine radar. X-band radar system can observe shape, size, and velocity of rip currents, which is difficult to obtain through field observation by conventional device. Algorithms which automatically detect locations, shapes, and magnitudes of rip currents were developed using time averaged X-band radar sea clutter images. X-band sea clutter images are transformed through 3D FFT into 2D wave number spectrum and frequency spectrum. Rip current velocities were estimated using differences in wave-number spectra and wave frequency spectra due to Doppler shift. The algorithm was …

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