Physical Sciences and Mathematics Commons^™

Semi-Inclusive Πº Target And Beam-Target Asymmetries From 6 Gev Electron Scattering With Clas, S. Koirala, S E. Kuhn, D. Adikaram, M. J. Amaryan, S. Bültmann, G. Charles, Gail Dodge, N. Guler, M. Khachatryan, A. Klein, Y. Prok, L. B. Weinstein, Z. W. Zhao

Physics Faculty Publications

We present precision measurements of the target and beam-target spin asymmetries from neutral pion electroproduction in deep-inelastic scattering (DIS) using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. We scattered 6-GeV, longitudinally polarized electrons off longitudinally polarized protons in a cryogenic ¹⁴NH₃ target, and extracted double and single target spin asymmetries for ep → e′π⁰X in multidimensional bins in four-momentum transfer (1.0 < Q² < 3.2 GeV²), Bjorken-x (0.12 < x < 0.48), hadron energy fraction (0.4 < z < 0.7), transverse pion momentum (0 < P_T < 1.0 GeV), and azimuthal angle ϕ_h between the lepton scattering and hadron production planes. We extracted asymmetries as a function of both x and P_T, which provide access to transverse-momentum …

First Measurement Of The Ar (E,E')X Cross Section At Jefferson Laboratory, H. Dai, M. Murphy, V. Pandey, D. Abrams, D. Nguyen, B. Aljawrneh, F. Hauenstein, D. W. Higinbotham, Charles Hyde, The Jefferson Lab Hall A Collaboration

Physics Faculty Publications

The success of the ambitious programs of both long- and short-baseline neutrino-oscillation experiments employing liquid-argon time-projection chambers will greatly rely on the precision with which the weak response of the argon nucleus can be estimated. In the E12-14-012 experiment at Jefferson Lab Hall A, we studied the properties of the argon nucleus by scattering a high-quality electron beam off a high-pressure gaseous argon target. Here, we present the measured ⁴⁰Ar(e,e') double differential cross section at incident electron energy E=2.222 GeV and scattering angle Θ = 15.54°. The data cover a broad range of energy transfers, where quasielastic scattering and …

Comparison Between The Water Activation Effects By Pulsed And Sinusoidal Helium Plasma Jets, Han Xu, Dingxin Liu, Wenjie Xia, Chen Chen, Weitao Wang, Zhijie Liu, Xiaohua Wang, Michael G. Kong

Bioelectrics Publications

Comparisons between pulsed and sinusoidal plasma jets have been extensively reported for the discharge characteristics and gaseous reactive species, but rarely for the aqueous reactive species in water solutions treated by the two types of plasma jets. This motivates us to compare the concentrations of aqueous reactive species induced by a pulsed and a sinusoidal plasma jet, since it is widely reported that these aqueous reactive species play a crucial role in various plasma biomedical applications. Experimental results show that the aqueous H₂O₂, OH/O₂⁻, and O₂⁻/ONOO⁻ induced by the …

Production And Correlation Of Reactive Oxygen And Nitrogen Species In Gas- And Liquid-Phase Generated By Helium Plasma Jets Under Different Pulse Widths, Zhijie Liu, Chunxi Zhou, Dingxin Liu, Dehui Xu, Wenjie Xia, Qingjie Cui, Bingchuan Wang, Michael G. Kong

Bioelectrics Publications

In this paper, we present the effects of the pulse width (PW) on the plasma jet's discharge characteristics, particularly focusing on the production and correlation of the reactive oxygen and nitrogen species (RONS) in gas- and liquid-phase. It is found that the length of plasma jet plume first increases before the PW of 10 μs, then gradually decreases and finally almost remains unchanged beyond 150 μs. The plasma bullet disappears after the falling edge of the voltage pulse at low PW, while it terminates far ahead of the falling edge of voltage pulse at high PW. This is …

Cryogenic Test Results Of The Sps Prototype Rf-Dipole Crabbing Cavity With Higher Order Mode Couplers, Subashini De Silva, H. Park, Jean R. Delayen, Z. Li

Physics Faculty Publications

The rf-dipole crabbing cavity planned for the LHC High Luminosity Upgrade is designed to deliver a transverse kick of 3.34 MV; crabbing the proton beam in the horizontal plane. The proton beams of the LHC machine operating at 7 TeV each sets high impedance thresholds on the crabbing cavity systems. The rf-dipole crabbing cavity is designed with a two higher order mode couplers to suppress those HOMs. The first prototype of the HOM couplers are fabricated at Jefferson Lab. This paper reports the cryogenic test results of the HOM couplers with the SPS prototype rf-dipole cavity.

Investigation Of The Surface Resistance Of Niobium Between 325 Mhz And 1300 Mhz Using A Coaxial Half-Wave Cavity, Hyekyoung Park, Jean R. Delayen, Subashini De Silva

Physics Faculty Publications

The Center for Accelerator Science at Old Dominion University has built a half-wave coaxial cavity (*) to measure the surface resistance of niobium as a function of frequency, temperature, rf field, preparation techniques, over a wide range of frequencies of interest for particle accelerators. The characteristics of the half-wave coaxial cavity provide these information on a same surface. The preliminary results showed clearly the frequency dependence of residual surface resistance (**). After establishing baseline, we have conducted a study of low temperature baking effect on the surface resistance under controlled environment. This paper will describe the details of the test …

Mobile Free-Electron Laser For Remote Atmospheric Survey, S. Johnson, Balša Terzić, Geoffrey A. Krafft

Physics Faculty Publications

Reliable atmospheric surveys for carbon distributions will be essential to building an understanding of the Earth's carbon cycle and the role it plays in climate change. One of the core needs of NASA 's Active Sensing of CO2 Over Nights, Days and Seasons (ASCENDS) Mission is to advance the range and precision of current remote atmospheric survey techniques. The feasibility of using accelerator-based sources of infrared light to improve current airborne lidar systems has been explored. A literary review has been conducted to asses the needs of ASCENDS versus the current capabilities of modern atmospheric survey technology, and the parameters …

Dynamic Output Feedback Invariants Of Full Relative Degree Nonlinear Siso Systems, W. Steven Gray, Luis A. Duffaut Espinosa

Electrical & Computer Engineering Faculty Publications

The goal of this paper is to explicitly describe invariants of a plant described by a Chen--Fliess series under a class of dynamic output feedback laws using earlier work by the authors on feedback transformation groups. The main result requires the rather strong assumption that the plant has a generating series with both finite Lie rank and full relative degree. In which case, there is no loss of generality in working with state space realizations of the plant. An additional genericness assumption regarding the normal form of the plant is also required, but as shown by the examples, this condition …

Client-Assisted Memento Aggregation Using The Prefer Header, Mat Kelly, Sawood Alam, Michael L. Nelson, Michele C. Weigle

Computer Science Faculty Publications

[First paragraph] Preservation of the Web ensures that future generations have a picture of how the web was. Web archives like Internet Archive's Wayback Machine, WebCite, and archive.is allow individuals to submit URIs to be archived, but the captures they preserve then reside at the archives. Traversing these captures in time as preserved by multiple archive sources (using Memento [8]) provides a more comprehensive picture of the past Web than relying on a single archive. Some content on the Web, such as content behind authentication, may be unsuitable or inaccessible for preservation by these organizations. Furthermore, this content may be …

Fliess Operator Representations Of Markov Jump Nonlinear Systems And Their Parallel Interconnections, Luis A. Duffaut Espinosa, W. Steven Gray

Electrical & Computer Engineering Faculty Publications

This paper provides a Fliess operator representation for a class of continuous-time Markov jump nonlinear systems. This representation allows one to describe the parallel sum and product interconnections of such systems. The paper concludes by showing that all parallel interconnections preserves rationality when the component operators have rational generating series.

Life In Hampton Roads Survey Press Release #6: Sea Level Rise And Flooding, Social Science Research Center, Old Dominion University

Life in Hampton Roads Survey Report

[Introductory paragraph]

This report examines regional measures of environmental risk perceptions from the 2018 Life In Hampton Roads survey (LIHR 2018) conducted by the Old Dominion University Social Science Research Center. Data from prior years is also provided when available to show comparisons in responses over time. Responses were weighted by city population, race, age, gender, and phone usage (cell versus land-line) to be representative of the Hampton Roads region. For additional information on survey methodology, and analyses of other issues, please see the SSRC website at www.odu.edu/ssrc. The 2018 Life in Hampton Roads survey included a series of …

Urban Areas In Coastal Zones, Richard C. Dawson, M. Shah Alam Khan, Vivien Gornitz, Maria Fernanda Lemos, Larry Atkinson, Julie Pullen, Juan Camilo Osorio, Lindsay Usher, Cynthia Rosenzweig (Ed.), William Solecki (Ed.), Patricia Romero-Lankao (Ed.), Shagun Mehrotra (Ed.), Shobhakar Dhakal (Ed.), Somayya Ali Ibrahim (Ed.)

CCPO Publications

[First Paragraph] Coastal cities have been subjected to extreme weather events since the onset of urbanization. Climatic change, in particular sea level rise, coupled with rapid urban development are amplifying the challenge of managing risks to coastal cities. Moreover, urban expansion and changes and intensification in land use further pressure sensitive coastal environments through pollution and habitat loss.

Isoscalar Ππ; Kk; Ηη Scattering And The Σ; F0; F2 Mesons From Qcd, Raul A. Briceño, Jozef J. Dudek, Robert G. Edwards, David J. Wilson

Physics Faculty Publications

We present the first lattice QCD study of coupled isoscalar ππ;K ¯K; ηη S- and D-wave scattering extracted from discrete finite-volume spectra computed on lattices which have a value of the light quark mass corresponding to m_π ∼ 391 MeV. In the J^P = 0⁺ sector we find analogues of the experimental σ and f₀ (980) states, where the σ appears as a stable bound-state below ππ threshold, and, similar to what is seen in experiment, the f₀ (980) manifests itself as a dip in the ππ cross section in the vicinity of the …

Dynamic Control Of Particle Separation In Deterministic Lateral Displacement Separator With Viscoelastic Fluids, Yuke Li, Hongna Zhang, Yongyao Li, Xiaobin Li, Jian Wu, Shizhi Qian, Fengchen Li

Mechanical & Aerospace Engineering Faculty Publications

We proposed an innovative method to achieve dynamic control of particle separation by employing viscoelastic fluids in deterministic lateral displacement (DLD) arrays. The effects of shear-thinning and elasticity of working fluids on the critical separation size in DLD arrays are investigated. It is observed that each effect can lead to the variation of the critical separation size by approximately 40%. Since the elasticity strength of the fluid is related to the shear rate, the dynamic control can for the first time be easily realized through tuning the flow rate in microchannels.

New Dimensions For A Challenging Security Environment: Growing Exposure To Critical Space Infrastructure Disruption Risk, Adrian V. Gheorghe, Alexandru Georgescu, Olga Bucovetchi, Marilena Lazăr, Cezar Scarlat

Engineering Management & Systems Engineering Faculty Publications

Space systems have become a key enabler for a wide variety of applications that are vital to the functioning of advanced societies. The trend is one of quantitative and qualitative increase of this dependence, so much so that space systems have been described as a new example of critical infrastructure. This article argues that the existence of critical space infrastructures implies the emergence of a new category of disasters related to disruption risks. We inventory those risks and make policy recommendations for what is, ultimately, a resilience governance issue.

Economics-Based Risk Management Of Distributed Denial Of Service Attacks: A Distance Learning Case Study, Omer Keskin, Unal Tatar, Omer Poyraz, Ariel Pinto, Adrian Gheorghe

Engineering Management & Systems Engineering Faculty Publications

Managing risk of cyber systems is still on the top of the agendas of Chief Information Security Officers (CISO). Investment in cybersecurity is continuously rising. Efficiency and effectiveness of cybersecurity investments are under scrutiny by boards of the companies. The primary method of decision making on cybersecurity adopts a risk-informed approach. Qualitative methods bring a notion of risk. However, particularly for strategic level decisions, more quantitative methods that can calculate the risk and impact in monetary values are required. In this study, a model is built to calculate the economic value of business interruption during a Distributed Denial-of-Service (DDoS) attack …

An Attribute Agreement Method For Hfacs Inter-Rater Reliability Assessment, Teddy Steven Cotter, Veysel Yesilbas

Engineering Management & Systems Engineering Faculty Publications

Inter-rater reliability can be regarded as the degree of agreement among raters on a given item or a circumstance. Multiple approaches have been taken to estimate and improve inter-rater reliability of the United States Department of Defense Human Factors Analysis and Classification System used by trained accident investigators. In this study, three trained instructor pilots used the DoD-HFACS to classify 347 U.S. Air Force Accident Investigation Board (AIB) Class-A reports between the years of 2000 and 2013. The overall method consisted of four steps: (1) train on HFACS definitions, (2) verify rating reliability, (3) rate HFACS reports, and (4) random …

A Proposed Taxonomy For The Systems Statistical Engineering Body Of Knowledge, Teddy Steven Cotter

Engineering Management & Systems Engineering Faculty Publications

In the ASEM-IAC 2012, Cotter (2012) identified the gaps in knowledge that statistical engineering needs to address, explored additional gaps in knowledge not addressed in the prior works, and set forth a working definition of and body of knowledge for statistical engineering. In the ASEM-IAC 2015, Cotter (2015) proposed a systemic causal Bayesian hierarchical model that addressed the knowledge gap needed to integrate deterministic mathematical engineering causal models within a stochastic framework. Missing, however, is the framework for specifying the hierarchical qualitative systems structures necessary and sufficient for specifying systemic causal Bayesian hierarchical models. In the ASEM-IAC 2016, Cotter (2016) …

Research Agenda In Developing Core Reference Ontology For Human Intelligence/Machine-Intelligence Electronic Medical Records System, Ziniya Zahedi, Teddy Steven Cotter

Engineering Management & Systems Engineering Faculty Publications

Beginning around 1990, efforts were initiated in the medical profession by the U.S. government to transition from paper based medical records to electronic medical records (EMR). By the late 1990s, EMR implementation had already encountered multiple barriers and failures. Then President Bush set forth the goal of implementing electronic health records (EHRs), nationwide within ten years. Again, progress toward EMR implementation was not realized. President Obama put new emphasis on promoting EMR and health care technology. The renewed emphasis did not overcome many of the original problems and induced new failures. Retrospective analyses suggest that failures were induced because programmers …

Swimming In A Sea Of Javascript Or: How I Learned To Stop Worrying And Love High-Fidelity Replay, John A. Berlin, Michael L. Nelson, Michele C. Weigle

Computer Science Faculty Publications

[First paragraph] Preserving and replaying modern web pages in high-fidelity has become an increasingly difficult task due to the increased usage of JavaScript. Reliance on server-side rewriting alone results in live-leakage and or the inability to replay a page due to the preserved JavaScript performing an action not permissible from the archive. The current state-of-the-art high fidelity archival preservation and replay solutions rely on handcrafted client-side URL rewriting libraries specifically tailored for the archive, namely Webrecoder's and Pywb's wombat.js [12]. Web archives not utilizing client-side rewriting rely on server-side rewriting that misses URLs used in a manner not accounted for …

It Is Hard To Compute Fixity On Archived Web Pages, Mohamed Aturban, Michael L. Nelson, Michele C. Weigle

Computer Science Faculty Publications

[Introduction] Checking fixity in web archives is performed to ensure archived resources, or mementos (denoted by URI-M) have remained unaltered since when they were captured. The final report of the PREMIS Working Group [2] defines information used for fixity as "information used to verify whether an object has been altered in an undocumented or unauthorized way." The common technique for checking fixity is to generate a current hash value (i.e., a message digest or a checksum) for a file using a cryptographic hash function (e.g., SHA-256) and compare it to the hash value generated originally. If they have different hash …

Evidence For Ephemeral Middle Eocene To Early Oligocene Greenland Glacial Ice And Pan-Arctic Sea Ice, Aradhna Tripati, Dennis Darby

OES Faculty Publications

Earth's modern climate is defined by the presence of ice at both poles, but that ice is now disappearing. Therefore understanding the origin and causes of polar ice stability is more critical than ever. Here we provide novel geochemical data that constrain past dynamics of glacial ice on Greenland and Arctic sea ice. Based on accurate source determinations of individual ice-rafted Fe-oxide grains, we find evidence for episodic glaciation of distinct source regions on Greenland as far-ranging as ~68°N and ~80°N synchronous with ice-rafting from circum-Arctic sources, beginning in the middle Eocene. Glacial intervals broadly coincide with reduced CO_{2 …}

The Biogeochemical Cycling Of Iron, Copper, Nickel, Cadmium, Manganese, Cobalt, Lead, And Scandium In A California Current Experimental Study, Travis Mellett, Matthew T. Brown, P. Dreux Chappell, Carolyn Duckham, Jessica N. Fitzsimmons, Claire P. Till, Robert M. Sherrell, Maria T. Maldonado, Kristen N. Buck

OES Faculty Publications

A 3-day shipboard incubation experiment was conducted in the California Current System in July 2014 to investigate the cycling of iron (Fe), copper (Cu), nickel (Ni), cadmium (Cd), manganese (Mn), cobalt (Co), lead (Pb), and scandium (Sc) under a range of light and particle conditions. Filtered (< 0.2 μm) and unfiltered treatments were incubated under the following light conditions: Dark, light (“UV”), and light without the ultraviolet (UV) wavelengths (“noUV”). The experiment was sampled for carbon and Fe uptake rates, dissolved trace metal concentrations (Fe, Cu, Ni, Cd, Mn, Co, Pb, Sc), Fe and Cu speciation, size-fractionated concentrations of Cd and Fe, and diatom community composition from DNA sequencing. Exposure to UV light increased phytoplankton Fe uptake in the first 24 h of the incubation relative to the noUV treatment, suggesting that a fraction of the ambient ligand-bound Fe was photoreactive. Fe-binding organic ligand production was observed in the unfiltered light treatments in association with increasing chlorophyll a, and evidence for Cu-binding ligand production in these treatments was also observed. Biological uptake of Cd and Co was observed along with scavenging of dissolved Pb. Manganese appeared to be rapidly oxidized by Mn-oxidizing bacteria with concomitant drawdown of dissolved Ni. Scandium displayed similar trends to Fe, reinforcing the limited observations …

A Survey Of Archival Replay Banners, Sawood Alam, Mat Kelly, Michele C. Weigle, Michael L. Nelson

Computer Science Faculty Publications

We surveyed various archival systems to compare and contrast different techniques used to implement an archival replay banner. We found that inline plain HTML injection is the most common approach, but prone to style conflicts. Iframe-based banners are also very common and while they do not have style conflicts, they suffer from screen real estate wastage and limited design choices. Custom Elements-based banners are promising, but due to being a new web standard, these are not yet widely deployed.

205.3 The Many Shapes Of Archive-It, Shawn Jones, Michael L. Nelson, Alexander Nwala, Michele C. Weigle

Computer Science Faculty Publications

Web archives, a key area of digital preservation, meet the needs of journalists, social scientists, historians, and government organizations. The use cases for these groups often require that they guide the archiving process themselves, selecting their own original resources, or seeds, and creating their own web archive collections. We focus on the collections within Archive-It, a subscription service started by the Internet Archive in 2005 for the purpose of allowing organizations to create their own collections of archived web pages, or mementos. Understanding these collections could be done via their user-supplied metadata or via text analysis, but the metadata is …

An Investigation Of Atomic Structures Derived From X-Ray Crystallography And Cryo-Electron Microscopy Using Distal Blocks Of Side-Chains, Lin Chen, Jing He, Salim Sazzed, Rayshawn Walker

Computer Science Faculty Publications

Cryo-electron microscopy (cryo-EM) is a structure determination method for large molecular complexes. As more and more atomic structures are determined using this technique, it is becoming possible to perform statistical characterization of side-chain conformations. Two data sets were involved to characterize block lengths for each of the 18 types of amino acids. One set contains 9131 structures resolved using X-ray crystallography from density maps with better than or equal to 1.5 Å resolutions, and the other contains 237 protein structures derived from cryo-EM density maps with 2-4 Å resolutions. The results show that the normalized probability density function of block …

Efficient Randomized Algorithms For The Fixed Precision Low Rank Matrix Approximation, Wenjian Yu, Yu Gu, Yaohang Li

Computer Science Faculty Publications

Randomized algorithms for low-rank matrix approximation are investigated, with the emphasis on the fixed-precision problem and computational efficiency for handling large matrices. The algorithms are based on the so-called QB factorization, where Q is an orthonormal matrix. First, a mechanism for calculating the approximation error in the Frobenius norm is proposed, which enables efficient adaptive rank determination for a large and/or sparse matrix. It can be combined with any QB-form factorization algorithm in which B's rows are incrementally generated. Based on the blocked randQB algorithm by Martinsson and Voronin, this results in an algorithm called randQB_EI. Then, we further revise …

Composition Of Dissolved Organic Matter In Pore Waters Of Anoxic Marine Sediments Analyzed By 1h Nuclear Magnetic Resonance Spectroscopy, Christina A. Fox, Hussain A. Abdulla, David J. Burdige, James P. Lewicki, Tomoko Komada

OES Faculty Publications

Marine sediments are globally significant sources of dissolved organic matter (DOM) to the oceans, but the biogeochemical role of pore-water DOM in the benthic and marine carbon cycles remains unclear due to a lack of understanding about the molecular composition of DOM. To help fill this knowledge gap, we used 1H nuclear magnetic resonance (NMR) spectroscopy to examine depth variability in the composition of pore-water DOM in anoxic sediments of Santa Barbara Basin, California Borderland. Proton detected spectra were acquired on whole samples without pre-concentration to avoid preclusion of any DOM components from the analytical window. Broad unresolved resonance (operationally …

Expected Limits On The Ocean Acidification Buffering Potential Of A Temperate Seagrass Meadow, David A. Koweek, R. C. Zimmerman, Kathryn M. Hewett, Brian Gaylord, Sarah N. Giddings, Kerry J. Nickols, Jennifer L. Ruesink, John J. Stachowicz, Yuichiro Takeshita, Ken Caldeira

OES Faculty Publications

Ocean acidification threatens many marine organisms, especially marine calcifiers. The only global‐scale solution to ocean acidification remains rapid reduction in CO₂ emissions. Nevertheless, interest in localized mitigation strategies has grown rapidly because of the recognized threat ocean acidification imposes on natural communities, including ones important to humans. Protection of seagrass meadows has been considered as a possible approach for localized mitigation of ocean acidification due to their large standing stocks of organic carbon and high productivity. Yet much work remains to constrain the magnitudes and timescales of potential buffering effects from seagrasses. We developed a biogeochemical box model to …

Blooms Of Dinoflagellate Mixotrophs In A Lower Chesapeake Bay Tributary: Carbon And Nitrogen Uptake Over Diurnal, Seasonal, And Interannual Timescales, Margaret R. Mulholland, Ryan Morse, Todd Egerton, Peter W. Bernhardt, K. C. Filippino

OES Faculty Publications

A multi-year study was conducted in the eutrophic Lafayette River, a sub-tributary of the lower Chesapeake Bay during which uptake of inorganic and organic nitrogen (N) and C compounds was measured during multiple seasons and years when different dinoflagellate species were dominant. Seasonal dinoflagellate blooms included a variety of mixotrophic dinoflagellates including Heterocapsa triquetra in the late winter, Prorocentrum minimum in the spring, Akashiwo sanguinea in the early summer, and Scrippsiella trochoidea and Cochlodinium polykrikoides in late summer and fall. Results showed that no single N source fueled algal growth, rather rates of N and C uptake varied on seasonal …