National Library of Energy BETA

Sample records for negative daily imbalances

  1. Operating a redox flow battery with a negative electrolyte imbalance

    DOE Patents [OSTI]

    Pham, Quoc; Chang, On; Durairaj, Sumitha

    2015-03-31

    Loss of flow battery electrode catalyst layers during self-discharge or charge reversal may be prevented by establishing and maintaining a negative electrolyte imbalance during at least parts of a flow battery's operation. Negative imbalance may be established and/or maintained actively, passively or both. Actively establishing a negative imbalance may involve detecting an imbalance that is less negative than a desired threshold, and processing one or both electrolytes until the imbalance reaches a desired negative level. Negative imbalance may be effectively established and maintained passively within a cell by constructing a cell with a negative electrode chamber that is larger than the cell's positive electrode chamber, thereby providing a larger quantity of negative electrolyte for reaction with positive electrolyte.

  2. CHARGE IMBALANCE

    SciTech Connect (OSTI)

    Clarke, John

    1980-09-01

    The purpose of this article is to review the theory of charge imbalance, and to discuss its relevance to a number of experimental situations. We introduce the concepts of quasiparticle charge and charge imbalance, and discuss the generation and detection of charge imbalance by tunneling. We describe the relaxation of the injected charge imbalance by inelastic scattering processes, and show how the Boltzmann equation can be solved to obtain the steady state quasiparticle distribution and the charge relaxation rate. Details are given of experiments to measure charge imbalance and the charge relaxation rate when inelastic scattering is the predominant relaxation mechanism. Experiments on and theories of other charge relaxation mechanisms are discussed, namely relaxation via elastic scattering in the presence of energy gap anisotropy, or in the presence of a pair breaking mechanism such as magnetic impurities or an applied supercurrent or magnetic field. We describe three other situations in which charge imbalance occurs, namely the resistance of the NS interface, phase slip centers, and the flow of a supercurrent in the presence of a temperature gradient.

  3. Dijet imbalance in hadronic collisions

    SciTech Connect (OSTI)

    Boer, Danieel; Mulders, Piet J.; Pisano, Cristian

    2009-11-01

    The imbalance of dijets produced in hadronic collisions has been used to extract the average transverse momentum of partons inside the hadrons. In this paper we discuss new contributions to the dijet imbalance that could complicate or even hamper this extraction. They are due to polarization of initial state partons inside unpolarized hadrons that can arise in the presence of nonzero parton transverse momentum. Transversely polarized quarks and linearly polarized gluons produce specific azimuthal dependences of the two jets that in principle are not suppressed. Their effects cannot be isolated just by looking at the angular deviation from the back-to-back situation; rather they enter jet broadening observables. In this way they directly affect the extraction of the average transverse momentum of unpolarized partons that is thought to be extracted. We discuss appropriately weighted cross sections to isolate the additional contributions.

  4. NREL: Transmission Grid Integration - Energy Imbalance Markets

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the Northwest Power Pool is currently ... operating reserves. Flexibility Reserve Reductions From an Energy Imbalance Market With High Levels of Wind Energy ...

  5. Energy Imbalance Markets (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2012-09-01

    The anticipated increase in variable renewable generation, such as wind and solar power, over the next several years has raised concerns about how system operators will maintain balance between electricity production and demand in the Western Interconnection, especially in its smaller balancing authority areas (BAAs). Given renewable portfolio standards in the West, it is possible that more than 50 gigawatts of wind capacity will be installed by 2020. Significant quantities of solar generation are likely to be added as well. Meanwhile, uncertainties about future load growth and challenges siting new transmission and generation resources may add additional stresses on the Western Interconnection of the future. One proposed method of addressing these challenges is an energy imbalance market (EIM). An EIM is a means of supplying and dispatching electricity to balance fluctuations in generation and load. It aggregates the variability of generation and load over multiple balancing areas (BAs).

  6. Frequency dependence of charge imbalance relaxation

    SciTech Connect (OSTI)

    Entin-Wohlman, O.; Orbach, R.

    1980-06-01

    A frequency-dependent charge imbalance relaxation rate near T/sub c/ is calculated in the presence of magnetic impurities in the gap regime (..delta.. >> GAMMA, where GAMMA is the pair-breaking rate) and in the gapless regime (..delta.. << GAMMA). In the former regime without magnetic impurities the results reduce to those of Artemenko, Volkov, and Zaitsev, and of Kadin. We show that their result can conveniently be derived from a Boltzmann equation for the quasiparticles.

  7. Operating Reserve Reductions From a Proposed Energy Imbalance...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Reserve Reductions From a Proposed Energy Imbalance Market With Wind and Solar Generation in the Western Interconnection J. King and B. Kirby Consultants M. Milligan National ...

  8. Western Interconnection Energy Imbalance Market Status and Prospects (Presentation)

    SciTech Connect (OSTI)

    Milligan, M.; Kirby, B.; King, J.; Beuning, S.

    2011-10-01

    This presentation describes how a new wholesale electricity market for energy imbalance ancillary services could be implemented and operated. Some conclusions of this presentation are: (1) Method for calculating additional reserve requirements due to wind and solar production; (2) EIM results in substantial reduction in reserves requirements and ramping demand; (3) Reduced participation reduces benefits for all but reduces the benefits to non-participants the most; (4) Full participation leads to maximum benefit across the Western Interconnection, up to 42% of total reserve requirement; and (5) Regional EIM implementations have smaller but substantial benefits.

  9. Backstage at the Daily Show

    Broader source: Energy.gov [DOE]

    Backstage footage from Secretary Chu's appearance on the Daily Show where he discuses the green room candy dish and possible lighting considerations.

  10. BPA Daily Notice (pbl/products)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Products > Products Daily Notice (surplus power) Transmission Losses Power Products Catalog Wind Smoothing and Intertie Service (Pilot) Firstgov BPA'S DAILY NOTICE Daily Notice...

  11. Natural Gas Weekly Update, Printer-Friendly Version

    Gasoline and Diesel Fuel Update (EIA)

    a 25 percent tolerance for negative daily imbalances. The restraint means that shippers must stay within the set percentage of daily scheduled volumes. Short-Term Energy Outlook...

  12. Natural Gas Weekly Update

    Gasoline and Diesel Fuel Update (EIA)

    Wednesday, August 23, with a 25 percent tolerance for negative daily imbalances. The restraint means that shippers must stay within the set percentage of daily scheduled volumes....

  13. Examination of Potential Benefits of an Energy Imbalance Market in the Western Interconnection

    SciTech Connect (OSTI)

    Milligan, M.; Clark, K.; King, J.; Kirby, B.; Guo, T.; Liu, G.

    2013-03-01

    In the Western Interconnection, there is significant interest in improving approaches to wide-area coordinated operations of the bulk electric power system, in part because of the increasing penetration of variable generation. One proposed solution is an energy imbalance market. This study focused on that approach alone, with the goal of identifying the potential benefits of an energy imbalance market in the year 2020.

  14. WAPA Daily Energy Accounting Activities

    Energy Science and Technology Software Center (OSTI)

    1990-10-01

    ISA (Interchange, Scheduling, & Accounting) is the interchange scheduling system used by the DOE Western Area Power Administration to perform energy accounting functions associated with the daily activities of the Watertown Operations Office (WOO). The system's primary role is to provide accounting functions for scheduled energy which is exchanged with other power companies and power operating organizations. The system has a secondary role of providing a historical record of all scheduled interchange transactions. The followingmore » major functions are performed by ISA: scheduled energy accounting for received and delivered energy; generation scheduling accounting for both fossil and hydro-electric power plants; metered energy accounting for received and delivered totals; energy accounting for Direct Current (D.C.) Ties; regulation accounting; automatic generation control set calculations; accounting summaries for Basin, Heartland Consumers Power District, and the Missouri Basin Municipal Power Agency; calculation of estimated generation for the Laramie River Station plant; daily and monthly reports; and dual control areas.« less

  15. Energy Assurance Daily | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Energy Assurance Daily Energy Assurance Daily Energy Assurance Daily provides a summary of public information concerning current energy issues. Published Monday through Friday to inform stakeholders of developments affecting energy systems, flows, and markets, it provides highlights of energy issues rather than a comprehensive coverage. Energy Assurance Daily covers: Major energy developments Electricity, petroleum, and natural gas industries Other relevant news Energy prices The Infrastructure

  16. Using Electric Vehicles to Mitigate Imbalance Requirements Associated with an Increased Penetration of Wind Generation

    SciTech Connect (OSTI)

    Tuffner, Francis K.; Kintner-Meyer, Michael CW

    2011-10-10

    The integration of variable renewable generation sources continues to be a significant area of focus for power system planning. Renewable portfolio standards and initiatives to reduce the dependency on foreign energy sources drive much of the deployment. Unfortunately, renewable energy generation sources like wind and solar tend to be highly variable in nature. To counter the energy imbalance caused by this variability, wind generation often requires additional balancing resources to compensate for the variability in the electricity production. With the expected electrification of transportation, electric vehicles may offer a new load resource for meeting all, or part, of the imbalance created by the renewable generation. This paper investigates a regulation-services-based battery charging method on a population of plug-in hybrid electric vehicles to meet the power imbalance requirements associated with the introduction of 11 GW of additional wind generation into the Northwest Power Pool. It quantifies the number of vehicles required to meet the imbalance requirements under various charging assumptions.

  17. Negative ion generator

    DOE Patents [OSTI]

    Stinnett, Regan W. (Albuquerque, NM)

    1984-01-01

    A negative ion generator is formed from a magnetically insulated transmission line having a coating of graphite on the cathode for producing negative ions and a plurality of apertures on the opposed anode for the release of negative ions. Magnetic insulation keeps electrons from flowing from the cathode to the anode. A transverse magnetic field removes electrons which do escape through the apertures from the trajectory of the negative ions.

  18. Negative ion generator

    DOE Patents [OSTI]

    Stinnett, R.W.

    1984-05-08

    A negative ion generator is formed from a magnetically insulated transmission line having a coating of graphite on the cathode for producing negative ions and a plurality of apertures on the opposed anode for the release of negative ions. Magnetic insulation keeps electrons from flowing from the cathode to the anode. A transverse magnetic field removes electrons which do escape through the apertures from the trajectory of the negative ions. 8 figs.

  19. Generation of charge imbalance in a superconductor by a temperature gradient

    SciTech Connect (OSTI)

    Entin-Wohlman, O.; Orbach, R.

    1980-11-01

    The charge-imbalance voltage in a superconductor carrying a current in the presence of a temperature gradient is calculated from the Boltzmann equation in the clean limit. We demonstrate why the Green's-function approach in the dirty limit, first performed by Schmid and Schoem, generates the same Boltzmann-like equation for the distribution function. In addition, the charge-imbalance voltage in the absence of an impressed current is calculated. It is shown to depend on del/sup 2/T+(delT)/sup 2//T, and not solely on (delT)/sup 2/. The calculations are limited to the temperature regime near T/sub c/, such that ..delta..<

  20. TWP-ICE Daily Synoptic Overview

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Daily Synoptic Overview 16 January - 14 February 2006 Lori Chappel Bureau of Meteorology Weather Overview * 13 January - 2 February 2006 Monsoon across north Australia; - 13-25...

  1. Energy Assurance Daily (EAD): June 2012

    Broader source: Energy.gov [DOE]

    Energy Assurance Daily provides a summary of public information concerning current energy issues. Published Monday through Friday to inform stakeholders of developments affecting energy systems,...

  2. Energy Assurance Daily (EAD): January- March 2012

    Office of Energy Efficiency and Renewable Energy (EERE)

    Energy Assurance Daily provides a summary of public information concerning current energy issues. Published Monday through Friday to inform stakeholders of developments affecting energy systems,...

  3. Energy Assurance Daily (EAD): April 2012

    Broader source: Energy.gov [DOE]

    Energy Assurance Daily provides a summary of public information concerning current energy issues. Published Monday through Friday to inform stakeholders of developments affecting energy systems,...

  4. Energy Assurance Daily (EAD): May 2012

    Office of Energy Efficiency and Renewable Energy (EERE)

    Energy Assurance Daily provides a summary of public information concerning current energy issues. Published Monday through Friday to inform stakeholders of developments affecting energy systems,...

  5. Energy Assurance Daily (EAD): July 2012

    Broader source: Energy.gov [DOE]

    Energy Assurance Daily provides a summary of public information concerning current energy issues. Published Monday through Friday to inform stakeholders of developments affecting energy systems,...

  6. Effects of inelastic electron-electron scattering on branch imbalance relaxation

    SciTech Connect (OSTI)

    Entin-Wohlman, O.; Orbach, R.

    1981-08-01

    The rate for branch-imbalance relaxation in a superconductor associated with inelastic electron-electron (Coulomb) scattering is derived, valid at arbitrary temperatures. The calculation is performed for clean superconductors, and shown to extend to cases where impurity scattering is important, using a technique of Schmid. As expected, for temperatures in the vicinity of T/sub c/ the form for the relaxation rate is identical with that arising from inelastic electron-phonon processes, if one replaces the inelastic electron-phonon scattering time with the inelastic electron-electron scattering time.

  7. THERMOELECTRIC GENERATION OF CHARGE IMBALANCE AT A SUPERCONDUCTOR-NORMAL METAL INTERFACE

    SciTech Connect (OSTI)

    Van Harlingen, D. J.

    1981-01-01

    The thermoelectric voltage produced across a superconductor-normal metal-superconductor (SNS) sandwich by an applied heat current has been measured in Pb-Cu-PbBi and In-Al-Sn as a function of temperature. The observed divergence of the thermoelectric voltage near T{sub c} is attributed to a charge imbalance region decaying into the superconductor from the NS interface over the quasiparticle diffusion length {lambda}{sub Q*}. The charge imbalance is generated by thermoelectrically driven quasiparticle currents in the superconductor. It contributes a voltage per unit heat power given by V{sub s}/P = {lambda}{sub Q*}S/{kappa}A, where A is the sample cross-sectional area, and S and {kappa} are the thermopower and the thermal conductivity of quasiparticles in the superconductor. For Pb and In, we find the measured thermopower in the superconducting state to be slowly-varying with temperature near T{sub c} and consistent in magnitude with normal state values. This result is in agreement with theoretical predictions of thermoelectric effects in superconductors but contrary to previous experimental results obtained by other methods.

  8. Negative electrode composition

    DOE Patents [OSTI]

    Kaun, Thomas D.; Chilenskas, Albert A.

    1982-01-01

    A secondary electrochemical cell and a negative electrode composition for use therewith comprising a positive electrode containing an active material of a chalcogen or a transiton metal chalcogenide, a negative electrode containing a lithium-aluminum alloy and an amount of a ternary alloy sufficient to provide at least about 5 percent overcharge capacity relative to a negative electrode solely of the lithium-aluminum alloy, the ternary alloy comprising lithium, aluminum, and iron or cobalt, and an electrolyte containing lithium ions in contact with both of the positive and the negative electrodes. The ternary alloy is present in the electrode in the range of from about 5 percent to about 50 percent by weight of the electrode composition and may include lithium-aluminum-nickel alloy in combination with either the ternary iron or cobalt alloys. A plurality of series connected cells having overcharge capacity can be equalized on the discharge side without expensive electrical equipment.

  9. Alternative Approaches to Calculate Benefits of an Energy Imbalance Market With Wind and Solar Energy: Preprint

    SciTech Connect (OSTI)

    Kirby, B.; King, J.; Milligan, M.

    2012-06-01

    The anticipated increase in variable generation in the Western Interconnection over the next several years has raised concerns about how to maintain system balance, especially in smaller Balancing Authority Areas (BAAs). Given renewable portfolio standards in the West, it is possible that more than 50 gigawatts of wind capacity will be installed by 2020. Significant quantities of solar generation are likely to be added as well. The consequent increase in variability and uncertainty that must be managed by the conventional generation fleet and responsive loads has resulted in a proposal for an Energy Imbalance Market (EIM). This paper extends prior work to estimate the reserve requirements for regulation, spinning, and non-spinning reserves with and without the EIM. We also discuss alternative approaches to allocating reserve requirements and show that some apparently attractive allocation methods have undesired consequences.

  10. Daylighter Daily Solar Roof Light | Open Energy Information

    Open Energy Info (EERE)

    Daylighter Daily Solar Roof Light Jump to: navigation, search Name: Daylighter Daily Solar Roof Light Address: 1991 Crocker Road, Suite 600 Place: Cleveland, Ohio Zip: 44145...

  11. Property:DailyOpWaterUseConsumed | Open Energy Information

    Open Energy Info (EERE)

    Property Name DailyOpWaterUseConsumed Property Type Number Description Daily Operation Water Use (afday) Consumed. Retrieved from "http:en.openei.orgwindex.php?titleProper...

  12. Property:DailyOpWaterUseGross | Open Energy Information

    Open Energy Info (EERE)

    Property Name DailyOpWaterUseGross Property Type Number Description Daily Operation Water Use (afday) Gross. Retrieved from "http:en.openei.orgwindex.php?titleProperty:...

  13. Spectroscopy of the soliton lattice formation in quasi-one-dimensional fermionic superfluids with population imbalance

    SciTech Connect (OSTI)

    Lutchyn, Roman M.; Dzero, Maxim; Yakovenko, Victor M.

    2011-09-15

    Motivated by recent experiments in low-dimensional trapped fermionic superfluids, we study a quasi-one-dimensional (quasi-1D) superfluid with a population imbalance between two hyperfine states using an exact mean-field solution for the order parameter. When an effective 'magnetic field' exceeds a critical value, the superfluid order parameter develops spatial inhomogeneity in the form of a soliton lattice. The soliton lattice generates a band of quasiparticle states inside the energy gap, which originate from the Andreev bound states localized at the solitons. Emergence of the soliton lattice is accompanied by formation of a spin-density wave, with the majority fermions residing at the points in space where the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) order parameter vanishes. We discuss possibilities for experimental detection of the quasi-1D FFLO state using elastic and inelastic optical Bragg scattering and radiofrequency spectroscopy. We show that these measurements can provide necessary information for unambiguous identification of the spatially inhomogeneous quasi-1D FFLO state and the soliton lattice formation.

  14. Negative ion source

    DOE Patents [OSTI]

    Leung, K.N.; Ehlers, K.W.

    1982-08-06

    An ionization vessel is divided into an ionizing zone and an extraction zone by a magnetic filter. The magnetic filter prevents high-energy electrons from crossing from the ionizing zone to the extraction zone. A small positive voltage impressed on a plasma grid, located adjacent an extraction grid, positively biases the plasma in the extraction zone to thereby prevent positive ions from migrating from the ionizing zone to the extraction zone. Low-energy electrons, which would ordinarily be dragged by the positive ions into the extraction zone, are thereby prevented from being present in the extraction zone and being extracted along with negative ions by the extraction grid. Additional electrons are suppressed from the output flux using ExB drift provided by permanent magnets and the extractor grid electrical field.

  15. Negative ion source

    DOE Patents [OSTI]

    Leung, K.N.; Ehlers, K.W.

    1984-12-04

    An ionization vessel is divided into an ionizing zone and an extraction zone by a magnetic filter. The magnetic filter prevents high-energy electrons from crossing from the ionizing zone to the extraction zone. A small positive voltage impressed on a plasma grid, located adjacent an extraction grid, positively biases the plasma in the extraction zone to thereby prevent positive ions from migrating from the ionizing zone to the extraction zone. Low-energy electrons, which would ordinarily be dragged by the positive ions into the extraction zone, are thereby prevented from being present in the extraction zone and being extracted along with negative ions by the extraction grid. Additional electrons are suppressed from the output flux using ExB drift provided by permanent magnets and the extractor grid electrical field. 14 figs.

  16. Negative ion source

    DOE Patents [OSTI]

    Leung, Ka-Ngo; Ehlers, Kenneth W.

    1984-01-01

    An ionization vessel is divided into an ionizing zone and an extraction zone by a magnetic filter. The magnetic filter prevents high-energy electrons from crossing from the ionizing zone to the extraction zone. A small positive voltage impressed on a plasma grid, located adjacent an extraction grid, positively biases the plasma in the extraction zone to thereby prevent positive ions from migrating from the ionizing zone to the extraction zone. Low-energy electrons, which would ordinarily be dragged by the positive ions into the extraction zone, are thereby prevented from being present in the extraction zone and being extracted along with negative ions by the extraction grid. Additional electrons are suppressed from the output flux using ExB drift provided by permanent magnets and the extractor grid electrical field.

  17. Analysis of Benefits of an Energy Imbalance Market in the NWPP

    SciTech Connect (OSTI)

    Samaan, Nader A.; Bayless, Rich; Symonds, Mark; Nguyen, Tony B.; Jin, Chunlian; Wu, Di; Diao, Ruisheng; Makarov, Yuri V.; Kannberg, Landis D.; Guo, Tao; Dennison-Leonard , Sarah; Goodenough, Mike; Schellberg, Ron; Conger, Sid; Harris, Kevin; Rarity, Matt; Wallace, Steven; Austin, Jamie; Noteboom, Rod; Van Blaricom , Tim; McRunnel, Kim; Apperson, John; Empey, Marshall; Etingov, Pavel V.; Warady, Debra; Brush, Ray; Newkirk, Joshua; Williams, Peter; Landauer, Marv; Owen, Hugh; Morter, Wayne; Haraguchi, Keli; Portouw, Jim; Downey, kathryn; Sorey, Steve; Williams, Stan; Gossa, Teyent; Kalich, Clint; Damiano, Patrick; Macarthur, Clay; Martin, Tom; Hoerner, Joe; Knudsen, Steve; Johnson, Anders; Link, Rick; Holcomb, Dennis

    2013-10-18

    The Northwest Power Pool (NWPP) Market Assessment Committee (MC) Initiative, which was officially launched on March 19, 2012, set out to explore a range of alternatives that could help the Balancing Authorities and scheduling utilities in the NWPP area address growing operational and commercial challenges affecting the regional power system. The MC formed an Analytical Team with technical representatives from each of the member Balancing Areas in the NWPP and with staff of Pacific Northwest National Laboratory (PNNL). This Analytical Team was instructed to conduct extensive studies of intra-hour operation of the NWPP system in the year 2020 and of the NWPP region with 14,671 MW of wind penetration. The effort utilized a sub-hourly production cost model (the PLEXOS® computer model) that inputs data from the Western Electricity Coordinating Council (WECC)-wide Production Cost Model (PCM) to evaluate potential production cost savings. The Analytical Team was given two general options to evaluate: •Energy Imbalance Market (EIM): establishment of an automated, organized NWPP area market for economically supplying energy imbalance within the hour. •Enhanced Market-Operational Tools (EMT) that might augment or replace an EIM. The Analytical The Analytical Team built on the WECC-wide PCM data from prior work done in the WECC and carried forward the evolution of the original WECC Transmission Expansion Planning Policy Committee (TEPPC) 2020 PC0 data base. A large number of modifications and improvements were made to this case and the data were subjected to extensive review by the team members to improve the model representation of the Northwest (NW). MC meetings that were open to the public were held for interested parties to review and provide input to the study. Results for the test, base, and sensitivity case studies performed by the MC Initiative Analytical Team indicate that there are a wide range of benefits that could be obtained from the operation of an EIM in

  18. Negative ion source

    DOE Patents [OSTI]

    Delmore, James E.

    1987-01-01

    A method and apparatus for providing a negative ion source accelerates electrons away from a hot filament electron emitter into a region of crossed electric and magnetic fields arranged in a magnetron configuration. During a portion of the resulting cycloidal path, the electron velocity is reduced below its initial value. The electron accelerates as it leaves the surface at a rate of only slightly less than if there were no magnetic field, thereby preventing a charge buildup at the surface of the emitter. As the electron traverses the cycloid, it is decelerated during the second, third, and fourth quadrants, then reeccelerated as it approaches the end of the fourth quadrant to regain its original velocity. The minimum velocity occurs during the fourth quadrant, and corresponds to an electron temperature of 200.degree. to 500.degree. for the electric and magnetic fields commonly encountered in the ion sources of magnetic sector mass spectrometers. An ion source using the above-described thermalized electrons is also disclosed.

  19. Improved negative ion source

    DOE Patents [OSTI]

    Delmore, J.E.

    1984-05-01

    A method and apparatus for providing a negative ion source accelerates electrons away from a hot filament electron emitter into a region of crossed electric and magnetic fields arranged in a magnetron configuration. During a portion of the resulting cycloidal path, the electron velocity is reduced below its initial value. The electron accelerates as it leaves the surface at a rate of only slightly less than if there were no magnetic field, thereby preventing a charge buildup at the surface of the emitter. As the electron traverses the cycloid, it is decelerated during the second, third, and fourth quadrants, then reaccelerated as it approaches the end of the fourth quadrant to regain its original velocity. The minimum velocity occurs during the fourth quadrant, and corresponds to an electron temperature of 200 to 500/sup 0/C for the electric and magnetic fields commonly encountered in the ion sources of magnetic sector mass spectrometers. An ion source using the above-described thermalized electrons is also disclosed.

  20. Daily HMS Extremes in Met Data - Hanford Site

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Hanford Meteorological Station Daily HMS Extremes in Met Data Hanford Meteorological Station Real Time Met Data from Around the Site Current and Past 48 Hours HMS Observations Daily HMS Extremes in Met Data Met and Climate Data Summary Products Contacts / Hours Current NWS Forecast for the Tri-Cities NWS Windchill Chart Daily HMS Extremes in Met Data Email Email Page | Print Print Page | Text Increase Font Size Decrease Font Size This table shows the daily extremes at each of the remote stations

  1. TRENDS IN ESTIMATED MIXING DEPTH DAILY MAXIMUMS

    SciTech Connect (OSTI)

    Buckley, R; Amy DuPont, A; Robert Kurzeja, R; Matt Parker, M

    2007-11-12

    Mixing depth is an important quantity in the determination of air pollution concentrations. Fireweather forecasts depend strongly on estimates of the mixing depth as a means of determining the altitude and dilution (ventilation rates) of smoke plumes. The Savannah River United States Forest Service (USFS) routinely conducts prescribed fires at the Savannah River Site (SRS), a heavily wooded Department of Energy (DOE) facility located in southwest South Carolina. For many years, the Savannah River National Laboratory (SRNL) has provided forecasts of weather conditions in support of the fire program, including an estimated mixing depth using potential temperature and turbulence change with height at a given location. This paper examines trends in the average estimated mixing depth daily maximum at the SRS over an extended period of time (4.75 years) derived from numerical atmospheric simulations using two versions of the Regional Atmospheric Modeling System (RAMS). This allows for differences to be seen between the model versions, as well as trends on a multi-year time frame. In addition, comparisons of predicted mixing depth for individual days in which special balloon soundings were released are also discussed.

  2. Negative hydrogen ion production mechanisms

    SciTech Connect (OSTI)

    Bacal, M.; Wada, M.

    2015-06-15

    Negative hydrogen/deuterium ions can be formed by processes occurring in the plasma volume and on surfaces facing the plasma. The principal mechanisms leading to the formation of these negative ions are dissociative electron attachment to ro-vibrationally excited hydrogen/deuterium molecules when the reaction takes place in the plasma volume, and the direct electron transfer from the low work function metal surface to the hydrogen/deuterium atoms when formation occurs on the surface. The existing theoretical models and reported experimental results on these two mechanisms are summarized. Performance of the negative hydrogen/deuterium ion sources that emerged from studies of these mechanisms is reviewed. Contemporary negative ion sources do not have negative ion production electrodes of original surface type sources but are operated with caesium with their structures nearly identical to volume production type sources. Reasons for enhanced negative ion current due to caesium addition to these sources are discussed.

  3. Three chamber negative ion source

    DOE Patents [OSTI]

    Leung, K.N.; Ehlers, K.W.; Hiskes, J.R.

    1983-11-10

    It is an object of this invention provide a negative ion source which efficiently provides a large flux of negatively ionized particles. This invention provides a volume source of negative ions which has a current density sufficient for magnetic fusion applications and has electrons suppressed from the output. It is still another object of this invention to provide a volume source of negative ions which can be electrostatically accelerated to high energies and subsequently neutralized to form a high energy neutral beam for use with a magnetically confined plasma.

  4. Operating Reserve Reductions from a Proposed Energy Imbalance Market with Wind and Solar Generation in the Western Interconnection

    SciTech Connect (OSTI)

    King, J.; Kirby, B.; Milligan, M.; Beuning, S.

    2012-05-01

    This paper considers several alternative forms of an energy imbalance market (EIM) proposed in the nonmarket areas of the Western Interconnection. The proposed EIM includes two changes in operating practices that independently reduce variability and increase access to responsive resources: balancing authority cooperation and sub-hourly dispatch. As the penetration of variable generation increases on the power system, additional interest in coordination would likely occur. Several alternative approaches could be used, but consideration of any form of coordinated unit commitment is beyond the scope of this analysis. This report examines the benefits of several possible EIM implementations--both separately and in concert.

  5. New director of Jefferson Lab named (Daily Press) | Jefferson...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    https:www.jlab.orgnewsarticlesnew-director-jefferson-lab-named-daily-press New director of Jefferson Lab named Hugh Montgomery Hugh Montgomery has been named president of...

  6. Montana Total Maximum Daily Load Development Projects Wiki |...

    Open Energy Info (EERE)

    Wiki Jump to: navigation, search OpenEI Reference LibraryAdd to library Web Site: Montana Total Maximum Daily Load Development Projects Wiki Abstract Provides information on...

  7. Question of the Week: What Is Your Daily Commute Like?

    Broader source: Energy.gov [DOE]

    In data collected from 2005 through 2007, The U.S. Census Bureau found that 76% of workers drove alone to work. Tell us about your daily commute?

  8. Three chamber negative ion source

    DOE Patents [OSTI]

    Leung, Ka-Ngo; Ehlers, Kenneth W.; Hiskes, John R.

    1985-01-01

    A negative ion vessel is divided into an excitation chamber, a negative ionization chamber and an extraction chamber by two magnetic filters. Input means introduces neutral molecules into a first chamber where a first electron discharge means vibrationally excites the molecules which migrate to a second chamber. In the second chamber a second electron discharge means ionizes the molecules, producing negative ions which are extracted into or by a third chamber. A first magnetic filter prevents high energy electrons from entering the negative ionization chamber from the excitation chamber. A second magnetic filter prevents high energy electrons from entering the extraction chamber from the negative ionizing chamber. An extraction grid at the end of the negative ion vessel attracts negative ions into the third chamber and accelerates them. Another grid, located adjacent to the extraction grid, carries a small positive voltage in order to inhibit positive ions from migrating into the extraction chamber and contour the plasma potential. Additional electrons can be suppressed from the output flux using ExB forces provided by magnetic field means and the extractor grid electric potential.

  9. Operating Reserve Implication of Alternative Implementations of an Energy Imbalance Service on Wind Integration in the Western Interconnection: Preprint

    SciTech Connect (OSTI)

    Milligan, M.; Kirby, B.; King, J.; Beuning, S.

    2011-07-01

    During the past few years, there has been significant interest in alternative ways to manage power systems over a larger effective electrical footprint. Large regional transmission organizations in the Eastern Interconnection have effectively consolidated balancing areas, achieving significant economies of scale that result in a reduction in required reserves. Conversely, in the Western Interconnection there are many balancing areas, which will result in challenges if there is significant wind and solar energy development in the region. A recent proposal to the Western Electricity Coordinating Council suggests a regional energy imbalance service (EIS). To evaluate this EIS, a number of analyses are in process or are planned. This paper describes one part of an analysis of the EIS's implication on operating reserves under several alternative scenarios of the market footprint and participation. We improve on the operating reserves method utilized in the Eastern Wind Integration and Transmission Study and apply this modified approach to data from the Western Wind and Solar Integration Study.

  10. Their best defense is good fiscal sense (Daily Press) | Jefferson...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    https:www.jlab.orgnewsarticlestheir-best-defense-good-fiscal-sense-daily-press Their best defense is good fiscal sense Top Guard Security finds it can be a good idea to say,...

  11. Jefferson Lab: Laser gun to eventually shoot down missiles (Daily...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Jefferson Lab: Laser gun to eventually shoot down missiles (Daily Press) External Link: http:articles.dailypress.com2011-02-21newsdp-nws-jefferson-lab-201102211j... By ...

  12. JLab's economic footprint expands (Daily Press) | Jefferson Lab

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    JLab's economic footprint expands (Daily Press) External Link: http://articles.dailypress.com/2011-01-20/news/dp-nws-jlab-economy-20110120_1_je... By jlab_admin on Thu, 2011-01-2

  13. Italian Physicist Named Deputy Associate Director at JLab (Daily Press) |

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Jefferson Lab Italian Physicist Named Deputy Associate Director at JLab (Daily Press) External Link: http://www.dailypress.com/news/science/dead-rise-blog/dp-italian-physicist-named... By jlab_admin on Tue, 2012-02-1

  14. Invisible Science: Lab Breakthroughs in Our Daily Lives | Department of

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Energy Invisible Science: Lab Breakthroughs in Our Daily Lives Invisible Science: Lab Breakthroughs in Our Daily Lives April 24, 2012 - 2:30pm Addthis The Lab Breakthroughs video series focuses on the array of technological advancements and discoveries that stem from research performed in the National Labs, including improvements in industrial processes, discoveries in fundamental scientific research, and innovative medicines. <a href="http://energy.gov/lab-breakthroughs">See

  15. Spectroscopic Evidence for Negative Electronic Compressibility...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Spectroscopic Evidence for Negative Electronic Compressibility in a Quasi-three-dimensional Spin-orbit Correlated Metal Tuesday, June 30, 2015 Negative compressibility is a sign of...

  16. Flexibility Reserve Reductions from an Energy Imbalance Market with High Levels of Wind Energy in the Western Interconnection

    SciTech Connect (OSTI)

    King, J.; Kirby, B.; Milligan, M.; S. Beuning

    2011-10-01

    The anticipated increase in variable generation in the Western Interconnection (WI) over the next several years has raised concerns about how to maintain system balance, especially in smaller Balancing Areas (BAs). Given renewable portfolio standards in the West, it is possible that more than 50 gigawatts (GW) of wind capacity will be installed by 2020. Significant quantities of solar generation are likely to be added as well. The consequent increase in variability and uncertainty that must be managed by the conventional generation fleet and responsive load make it attractive to consider ways in which Balancing Area Authorities (BAAs) can pool their variability and response resources, thus taking advantage of geographic and temporal diversity to increase overall operational efficiency. Our analysis considers several alternative forms of an Energy Imbalance Market (EIM) that have been proposed in the non-market areas of the WI. The proposed EIM includes two changes in operating practices that independently reduce variability and increase access to responsive resources: BAA cooperation and sub-hourly dispatch. As proposed, the EIM does not consider any form of coordinated unit commitment; however, over time it is possible that BAAs would develop formal or informal coordination plans. This report examines the benefits of several possible EIM implementations, both separately and in concert.

  17. Negative mass solitons in gravity

    SciTech Connect (OSTI)

    Cebeci, Hakan; Sarioglu, Oezguer; Tekin, Bayram

    2006-03-15

    We first reconstruct the conserved (Abbott-Deser) charges in the spin-connection formalism of gravity for asymptotically (Anti)-de Sitter spaces, and then compute the masses of the AdS soliton and the recently found Eguchi-Hanson solitons in generic odd dimensions, unlike the previous result obtained for only five dimensions. These solutions have negative masses compared to the global AdS or AdS/Z{sub p} spacetimes. As a separate note, we also compute the masses of the recent even dimensional Taub-NUT-Reissner-Nordstroem metrics.

  18. Entanglement negativity in the multiverse

    SciTech Connect (OSTI)

    Kanno, Sugumi; Shock, Jonathan P.; Soda, Jiro

    2015-03-10

    We explore quantum entanglement between two causally disconnected regions in the multiverse. We first consider a free massive scalar field, and compute the entanglement negativity between two causally separated open charts in de Sitter space. The qualitative feature of it turns out to be in agreement with that of the entanglement entropy. We then introduce two observers who determine the entanglement between two causally disconnected de Sitter spaces. When one of the observers remains constrained to a region of the open chart in a de Sitter space, we find that the scale dependence enters into the entanglement. We show that a state which is initially maximally entangled becomes more entangled or less entangled on large scales depending on the mass of the scalar field and recovers the initial entanglement in the small scale limit. We argue that quantum entanglement may provide some evidence for the existence of the multiverse.

  19. Once-Daily Radiation Therapy for Inflammatory Breast Cancer

    SciTech Connect (OSTI)

    Brown, Lindsay; Harmsen, William; Blanchard, Miran; Goetz, Matthew; Jakub, James; Mutter, Robert; Petersen, Ivy; Rooney, Jessica; Stauder, Michael; Yan, Elizabeth; Laack, Nadia

    2014-08-01

    Purpose: Inflammatory breast cancer (IBC) is a rare and aggressive breast cancer variant treated with multimodality therapy. A variety of approaches intended to escalate the intensity and efficacy of radiation therapy have been reported, including twice-daily radiation therapy, dose escalation, and aggressive use of bolus. Herein, we examine our outcomes for patients treated with once-daily radiation therapy with aggressive bolus utilization, focusing on treatment technique. Methods and Materials: A retrospective review of patients with nonmetastatic IBC treated from January 1, 2000, through December 31, 2010, was performed. Locoregional control (LRC), disease-free survival (DFS), overall survival (OS) and predictors thereof were assessed. Results: Fifty-two women with IBC were identified, 49 (94%) of whom were treated with neoadjuvant chemotherapy. All underwent mastectomy followed by adjuvant radiation therapy. Radiation was delivered in once-daily fractions of 1.8 to 2.25 Gy (median, 2 Gy). Patients were typically treated with daily 1-cm bolus throughout treatment, and 33 (63%) received a subsequent boost to the mastectomy scar. Five-year Kaplan Meier survival estimates for LRC, DFS, and OS were 81%, 56%, and 64%, respectively. Locoregional recurrence was associated with poorer OS (P<.001; hazard ratio [HR], 4.1). Extracapsular extension was associated with worse LRC (P=.02), DFS (P=.007), and OS (P=.002). Age greater than 50 years was associated with better DFS (P=.03). Pathologic complete response was associated with a trend toward improved LRC (P=.06). Conclusions: Once-daily radiation therapy with aggressive use of bolus for IBC results in outcomes consistent with previous reports using various intensified radiation therapy regimens. LRC remains a challenge despite modern systemic therapy. Extracapsular extension, age ≤50 years, and lack of complete response to chemotherapy appear to be associated with worse outcomes. Novel strategies are needed in IBC

  20. Automatic voltage imbalance detector

    DOE Patents [OSTI]

    Bobbett, Ronald E.; McCormick, J. Byron; Kerwin, William J.

    1984-01-01

    A device for indicating and preventing damage to voltage cells such as galvanic cells and fuel cells connected in series by detecting sequential voltages and comparing these voltages to adjacent voltage cells. The device is implemented by using operational amplifiers and switching circuitry is provided by transistors. The device can be utilized in battery powered electric vehicles to prevent galvanic cell damage and also in series connected fuel cells to prevent fuel cell damage.

  1. Energy Imbalance Market Update

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    in CAISO Market Jim Price, Senior Advisor, Market Development & Analysis California ISO CAISO Public Market minimizes bid costs, while accounting for multiple transmission...

  2. CHARGE-IMBALANCE RELAXATION IN THE PRESENCE OF A PAIR-BREAKING INTERACTION IN SUPERCONDUCTING AlEr FILMS

    SciTech Connect (OSTI)

    Lemberger, T.R.; Clarke, J.

    1980-07-01

    The charge-imbalance relaxation rate, 1/F*{sub T{sub Q*}}, has been measured in dirty superconducting AlEr films in which Er is a pair-breaking magnetic impurity that induces charge relaxation through elastic exchange scattering. Measurements were made in the range 0.1 {approx}< {Delta}(T)/k{sub B}T{sub c} {approx}< 1.4 for Er concentrations varying from 21 to 1660 at. ppm that produced estimated exchange scattering rates, {tau}{sub S}{sup -1}, from about 10{sup 9} sec{sup -1} to 5 x 10{sup 10} sec{sup -1}. Measured values of 1/F*{sub T{sub Q*}} were in good agreement with the Schmid-Schoen expression, 1/F*{sub T{sub Q*}}=({pi}{Delta}/4k{sub B}T{sub c}{tau}{sub E}) x (1+2{tau}{sub E}/{tau}{sub S}){sup 1/2}, for {Delta}/k{sub B}T{sub c} {approx}< 0.8, where {tau}{sub E}{sup -1} is the electron-phonon scattering rate estimated from the measured transition temperature. For larger values of {Delta}/k{sub B}T{sub c}, the relaxation rate increased less rapidly with {Delta}. The appropriate Boltzmann equation was solved on a computer to obtain values for 1/F*{sub T{sub Q*}} in the range 0.5 {approx}< T/T{sub c} {approx}< 0.999999. The computed values of 1/F*{sub T{sub Q*}} agreed with several analytic expressions valid for {Delta}/k{sub B}T{sub c} << 1, but not with the experimental data: The computed curves increased more rapidly than linearly with {Delta}/k{sub B}T{sub c} near T{sub c}, and the shape of the 1/F*{sub T{sub Q*}} vs {Delta}/k{sub B}T{sub c} curves was qualitatively different. This discrepancy suggests that either the generally accepted expression for exchange charge relaxation is incorrect, or that the Boltzmann equation is inappropriate for these calculations.

  3. Daily temperature and precipitation data for 223 USSR Stations

    SciTech Connect (OSTI)

    Razuvaev, V.N.; Apasova, E.G.; Martuganov, R.A.; Vose, R.S.; Steurer, P.M.

    1993-11-01

    On- May 23, 1972, the United States and the USSR established a bilateral initiative known as the Agreement on Protection of the Environment. Given recent interest in possible greenhouse gas-induced climate change, Working Group VIII (Influence of Environmental Changes on Climate) has become particularly useful to the scientific communities of both nations. Among its many achievements, Working Group VIII has been instrumental in the exchange of climatological information between the principal climate data centers of each country [i.e., the National Climatic Data Center (NCDC) in Asheville, North Carolina, and the Research Institute of Hydrometeorological Information in Obninsk, Russia]. Considering the relative lack of climate records previously available for the USSR, data obtained via this bilateral exchange are particularly valuable to researchers outside the former Soviet Union. To expedite the dissemination of these data, NOAA`s Climate and Global Change Program funded the Carbon Dioxide Information Analysis Center (CDIAC) and NCDC to distribute one of the more useful archives acquired through this exchange: a 223-station daily data set covering the period 1881-1989. This data set contains: (1) daily mean, minimum, and maximum temperature data; (2) daily precipitation data; (3) station inventory information (WMO No., name, coordinates, and elevation); (4) station history information (station relocation and rain gauge replacement dates); and (5) quality assurance information (i.e., flag codes that were assigned as a result of various data checks). The data set is available, free of charge, as a Numeric Data Package (NDP) from CDIAC. The NDP consists of 18 data files and a printed document which describes both the data files and the 223-station network in detail.

  4. Electrochemical cell and negative electrode therefor

    DOE Patents [OSTI]

    Kaun, Thomas D.

    1982-01-01

    A secondary electrochemical cell with the positive and negative electrodes separated by a molten salt electrolyte with the negative electrode comprising a particulate mixture of lithium-aluminum alloy and electrolyte and an additive selected from graphitized carbon, Raney iron or mixtures thereof. The lithium-aluminum alloy is present in the range of from about 45 to about 80 percent by volume of the negative electrode, and the electrolyte is present in an amount not less than about 10 percent by volume of the negative electrode. The additive of graphitized carbon is present in the range of from about 1 to about 10 percent by volume of the negative electrode, and the Raney iron additive is present in the range of from about 3 to about 10 percent by volume of the negative electrode.

  5. Effect of defect imbalance on void swelling distributions produced in pure iron irradiated with 3.5 MeV self-ions

    SciTech Connect (OSTI)

    Lin Shao; C.-C. Wei; J. Gigax; A. Aitkaliyeva; D. Chen; B.H. Sencer; F.A. Garner

    2014-10-01

    Ion irradiation has been widely used to simulate neutron-induced radiation damage. There are a number of features of ion-induced damage that differ from neutron-induced damage, however, and these differences require investigation before ion data can be confidently used to predict behavior arising from neutron bombardment. In this study 3.5 MeV self-ion irradiation of pure iron was used to study the influence on void swelling of the depth-dependent defect imbalance between vacancies and interstitials that arises from various surface effects, forward scattering of displaced atoms, and especially the injected interstitial effect. It was observed that the depth dependence of void swelling does not follow the behavior anticipated from the depth dependence of the damage rate. Void nucleation and growth develop first in the lower-dose, near-surface region, and then moves to progressively deeper and higher-damage depths during continued irradiation. This indicates a strong initial suppression of void nucleation in the peak damage region that is eventually overcome with continued irradiation. Using the Boltzmann transport equation method, this phenomenon is shown to be due to depth-dependent defect imbalances created under ion irradiation. These findings demonstrate that void swelling does not depend solely on the local dose level and that this sensitivity of swelling to depth must be considered in extraction and interpretation of ion-induced swelling data. 2014 El

  6. Effect of defect imbalance on void swelling distributions produced in pure iron irradiated with 3.5MeV self-ions

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Shao, Lin; Wei, C. -C.; Gigax, J.; Aitkaliyeva, A.; Chen, D.; Sencer, B. H.; Garner, F. A.

    2014-06-10

    Ion irradiation has been widely used to simulate neutron-induced radiation damage. There are a number of features of ion-induced damage that differ from neutron-induced damage, however, and these differences require investigation before ion data can be confidently used to predict behavior arising from neutron bombardment. In this study 3.5 MeV self-ion irradiation of pure iron was used to study the influence on void swelling of the depth-dependent defect imbalance between vacancies and interstitials that arises from various surface effects, forward scattering of displaced atoms, and especially the injected interstitial effect. It was observed that the depth dependence of void swellingmoredoes not follow the behavior anticipated from the depth dependence of the damage rate. Void nucleation and growth develop first in the lower-dose, near-surface region, and then moves to progressively deeper and higher-damage depths during continued irradiation. This indicates a strong initial suppression of void nucleation in the peak damage region that is eventually overcome with continued irradiation. Using the Boltzmann transport equation method, this phenomenon is shown to be due to depth-dependent defect imbalances created under ion irradiation. As a result, these findings demonstrate that void swelling does not depend solely on the local dose level and that this sensitivity of swelling to depth must be considered in extraction and interpretation of ion-induced swelling data.less

  7. Effect of defect imbalance on void swelling distributions produced in pure iron irradiated with 3.5 MeV self-ions

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Shao, Lin; Wei, C. -C.; Gigax, J.; Aitkaliyeva, A.; Chen, D.; Sencer, B. H.; Garner, F. A.

    2014-06-10

    Ion irradiation has been widely used to simulate radiation damage induced by neutrons. However, there are a number of features of ion-induced damage that differ from neutron-induced damage, and these differences require investigation before behavior arising from neutron bombardment can be confidently predicted from ion data. In this study 3.5 MeV self-ion irradiation of pure iron was used to study the influence on void swelling of the depth-dependent defect imbalance between vacancies and interstitials that arises from various surface effects, forward scattering of displaced atoms, and especially the injected interstitial effect. The depth dependence of void swelling was observed notmore » to follow the behavior anticipated from the depth dependence of the damage rate. Void nucleation and growth develop first in the lower-dose, near-surface region, and then, during continued irradiation, move to progressively deeper and higher-damage depths. This indicates a strong initial suppression of void nucleation in the peak damage region that continued irradiation eventually overcomes. This phenomenon is shown by the Boltzmann transport equation method to be due to depth-dependent defect imbalances created under ion irradiation. These findings thus demonstrate that void swelling does not depend solely on the local dose level and that this sensitivity of swelling to depth must be considered in extracting and interpreting ion-induced swelling data.« less

  8. Effect of defect imbalance on void swelling distributions produced in pure iron irradiated with 3.5 MeV self-ions

    SciTech Connect (OSTI)

    Shao, Lin; Wei, C. -C.; Gigax, J.; Aitkaliyeva, A.; Chen, D.; Sencer, B. H.; Garner, F. A.

    2014-06-10

    Ion irradiation has been widely used to simulate radiation damage induced by neutrons. However, there are a number of features of ion-induced damage that differ from neutron-induced damage, and these differences require investigation before behavior arising from neutron bombardment can be confidently predicted from ion data. In this study 3.5 MeV self-ion irradiation of pure iron was used to study the influence on void swelling of the depth-dependent defect imbalance between vacancies and interstitials that arises from various surface effects, forward scattering of displaced atoms, and especially the injected interstitial effect. The depth dependence of void swelling was observed not to follow the behavior anticipated from the depth dependence of the damage rate. Void nucleation and growth develop first in the lower-dose, near-surface region, and then, during continued irradiation, move to progressively deeper and higher-damage depths. This indicates a strong initial suppression of void nucleation in the peak damage region that continued irradiation eventually overcomes. This phenomenon is shown by the Boltzmann transport equation method to be due to depth-dependent defect imbalances created under ion irradiation. These findings thus demonstrate that void swelling does not depend solely on the local dose level and that this sensitivity of swelling to depth must be considered in extracting and interpreting ion-induced swelling data.

  9. Negative resistance in an organic thin film

    SciTech Connect (OSTI)

    Ehara, S. ); Takagi, T. ); Yoshida, T.; Inaba, H.; Naito, H.; Okuda, M. )

    1992-08-20

    This paper reports that the negative resistance of the tunneling currents was observed in a semiconducting organic thin film on a graphite substrate by an STM (Scanning Tunneling Microscopy). This negative resistance may be understood by the theory of a molecular resonance tunneling effect.

  10. Superconductive microstrip exhibiting negative differential resistivity

    DOE Patents [OSTI]

    Huebener, R.P.; Gallus, D.E.

    1975-10-28

    A device capable of exhibiting negative differential electrical resistivity over a range of values of current and voltage is formed by vapor- depositing a thin layer of a material capable of exhibiting superconductivity on an insulating substrate, establishing electrical connections at opposite ends of the deposited strip, and cooling the alloy into its superconducting range. The device will exhibit negative differential resistivity when biased in the current- induced resistive state.

  11. Carrier heating and negative photoconductivity in graphene

    SciTech Connect (OSTI)

    Heyman, J. N.; Stein, J. D.; Kaminski, Z. S.; Banman, A. R.; Massari, A. M.; Robinson, J. T.

    2015-01-07

    We investigated negative photoconductivity in graphene using ultrafast terahertz techniques. Infrared transmission was used to determine the Fermi energy, carrier density, and mobility of p-type chemical vapor deposition graphene samples. Time-resolved terahertz photoconductivity measurements using a tunable mid-infrared pump probed these samples at photon energies between 0.35 eV and 1.55 eV, approximately one-half to three times the Fermi energy of the samples. Although interband optical transitions in graphene are blocked for pump photon energies less than twice the Fermi energy, we observe negative photoconductivity at all pump photon energies investigated, indicating that interband excitation is not required to observe this effect. Our results are consistent with a thermalized free-carrier population that cools by electron-phonon scattering, but are inconsistent with models of negative photoconductivity based on population inversion.

  12. Negative electrodes for lithium cells and batteries

    DOE Patents [OSTI]

    Vaughey, John T.; Fransson, Linda M.; Thackeray, Michael M.

    2005-02-15

    A negative electrode is disclosed for a non-aqueous electrochemical cell. The electrode has an intermetallic compound as its basic structural unit with the formula M.sub.2 M' in which M and M' are selected from two or more metal elements including Si, and the M.sub.2 M' structure is a Cu.sub.2 Sb-type structure. Preferably M is Cu, Mn and/or Li, and M' is Sb. Also disclosed is a non-aqueous electrochemical cell having a negative electrode of the type described, an electrolyte and a positive electrode. A plurality of cells may be arranged to form a battery.

  13. Today in Energy - Daily Prices - Prices - U.S. Energy Information

    Gasoline and Diesel Fuel Update (EIA)

    Administration (EIA) September 2, 2016Daily Prices Daily wholesale and retail prices for various energy products are shown below, including spot prices and select futures prices at national or regional levels. Prices are updated each weekday (excluding federal holidays), typically between 7:30 and 8:30 a.m. This page is meant to provide a snapshot of selected daily prices only. Prices are republished by EIA with permission as follows: Wholesale Spot Petroleum Prices from Thomson Reuters,

  14. Characterizing Sub-Daily Flow Regimes: Implications of Hydrologic Resolution on Ecohydrology Studies

    SciTech Connect (OSTI)

    Bevelhimer, Mark S.; McManamay, Ryan A.; O'Connor, B.

    2014-05-26

    Natural variability in flow is a primary factor controlling geomorphic and ecological processes in riverine ecosystems. Within the hydropower industry, there is growing pressure from environmental groups and natural resource managers to change reservoir releases from daily peaking to run-of-river operations on the basis of the assumption that downstream biological communities will improve under a more natural flow regime. In this paper, we discuss the importance of assessing sub-daily flows for understanding the physical and ecological dynamics within river systems. We present a variety of metrics for characterizing sub-daily flow variation and use these metrics to evaluate general trends among streams affected by peaking hydroelectric projects, run-of-river projects and streams that are largely unaffected by flow altering activities. Univariate and multivariate techniques were used to assess similarity among different stream types on the basis of these sub-daily metrics. For comparison, similar analyses were performed using analogous metrics calculated with mean daily flow values. Our results confirm that sub-daily flow metrics reveal variation among and within streams that are not captured by daily flow statistics. Using sub-daily flow statistics, we were able to quantify the degree of difference between unaltered and peaking streams and the amount of similarity between unaltered and run-of-river streams. The sub-daily statistics were largely uncorrelated with daily statistics of similar scope. Furthermore, on short temporal scales, sub-daily statistics reveal the relatively constant nature of unaltered streamreaches and the highly variable nature of hydropower-affected streams, whereas daily statistics show just the opposite over longer temporal scales.

  15. Characterizing Sub-Daily Flow Regimes: Implications of Hydrologic Resolution on Ecohydrology Studies

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Bevelhimer, Mark S.; McManamay, Ryan A.; O'Connor, B.

    2014-05-26

    Natural variability in flow is a primary factor controlling geomorphic and ecological processes in riverine ecosystems. Within the hydropower industry, there is growing pressure from environmental groups and natural resource managers to change reservoir releases from daily peaking to run-of-river operations on the basis of the assumption that downstream biological communities will improve under a more natural flow regime. In this paper, we discuss the importance of assessing sub-daily flows for understanding the physical and ecological dynamics within river systems. We present a variety of metrics for characterizing sub-daily flow variation and use these metrics to evaluate general trends amongmore » streams affected by peaking hydroelectric projects, run-of-river projects and streams that are largely unaffected by flow altering activities. Univariate and multivariate techniques were used to assess similarity among different stream types on the basis of these sub-daily metrics. For comparison, similar analyses were performed using analogous metrics calculated with mean daily flow values. Our results confirm that sub-daily flow metrics reveal variation among and within streams that are not captured by daily flow statistics. Using sub-daily flow statistics, we were able to quantify the degree of difference between unaltered and peaking streams and the amount of similarity between unaltered and run-of-river streams. The sub-daily statistics were largely uncorrelated with daily statistics of similar scope. Furthermore, on short temporal scales, sub-daily statistics reveal the relatively constant nature of unaltered streamreaches and the highly variable nature of hydropower-affected streams, whereas daily statistics show just the opposite over longer temporal scales.« less

  16. MO-G-BRE-04: Automatic Verification of Daily Treatment Deliveries and Generation of Daily Treatment Reports for a MR Image-Guided Treatment Machine

    SciTech Connect (OSTI)

    Yang, D; Li, X; Li, H; Wooten, H; Green, O; Rodriguez, V; Mutic, S

    2014-06-15

    Purpose: Two aims of this work were to develop a method to automatically verify treatment delivery accuracy immediately after patient treatment and to develop a comprehensive daily treatment report to provide all required information for daily MR-IGRT review. Methods: After systematically analyzing the requirements for treatment delivery verification and understanding the available information from a novel MR-IGRT treatment machine, we designed a method to use 1) treatment plan files, 2) delivery log files, and 3) dosimetric calibration information to verify the accuracy and completeness of daily treatment deliveries. The method verifies the correctness of delivered treatment plans and beams, beam segments, and for each segment, the beam-on time and MLC leaf positions. Composite primary fluence maps are calculated from the MLC leaf positions and the beam-on time. Error statistics are calculated on the fluence difference maps between the plan and the delivery. We also designed the daily treatment delivery report by including all required information for MR-IGRT and physics weekly review - the plan and treatment fraction information, dose verification information, daily patient setup screen captures, and the treatment delivery verification results. Results: The parameters in the log files (e.g. MLC positions) were independently verified and deemed accurate and trustable. A computer program was developed to implement the automatic delivery verification and daily report generation. The program was tested and clinically commissioned with sufficient IMRT and 3D treatment delivery data. The final version has been integrated into a commercial MR-IGRT treatment delivery system. Conclusion: A method was developed to automatically verify MR-IGRT treatment deliveries and generate daily treatment reports. Already in clinical use since December 2013, the system is able to facilitate delivery error detection, and expedite physician daily IGRT review and physicist weekly chart

  17. Fact #917: March 21, 2016 Work Truck Daily Idle Time by Industry |

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Department of Energy 7: March 21, 2016 Work Truck Daily Idle Time by Industry Fact #917: March 21, 2016 Work Truck Daily Idle Time by Industry SUBSCRIBE to the Fact of the Week Results of the 2015 Work Truck Electrification and Idle Management Study showed the daily idle time for work truck fleets. Daily idle times by industry show that the truck fleets in the utility/telecommunications industry had the longest idle times. Thirty-nine percent of respondents indicated that their fleets idled

  18. McGinness Hills Well 27A-10 Daily Drilling Report Data

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Knudsen, Steven

    This data should be used with the daily drilling record and other data which can be obtained from the contact listed below

  19. McGinness Hills Well 27A-10 Daily Drilling Report Data

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Knudsen, Steven

    2014-03-25

    This data should be used with the daily drilling record and other data which can be obtained from the contact listed below

  20. Negative Electrode For An Alkaline Cell

    DOE Patents [OSTI]

    Coco, Isabelle; Cocciantelli, Jean-Michel; Villenave, Jean-Jacques

    1998-07-14

    The present invention concerns a negative electrode for an alkaline cell, comprising a current collector supporting a paste containing an electrochemically active material and a binder, characterized in that said binder is a polymer containing hydrophilic and hydrophobic groups, said polymer being selected from an acrylic homopolymer, copolymer and terpolymer, an unsaturated organic acid copolymer and an unsaturated acid anhydride copolymer.

  1. Is the negative glow plasma of a direct current glow discharge negatively charged?

    SciTech Connect (OSTI)

    Bogdanov, E. A.; Saifutdinov, A. I.; Demidov, V. I.; Kudryavtsev, A. A.

    2015-02-15

    A classic problem in gas discharge physics is discussed: what is the sign of charge density in the negative glow region of a glow discharge? It is shown that traditional interpretations in text-books on gas discharge physics that states a negative charge of the negative glow plasma are based on analogies with a simple one-dimensional model of discharge. Because the real glow discharges with a positive column are always two-dimensional, the transversal (radial) term in divergence with the electric field can provide a non-monotonic axial profile of charge density in the plasma, while maintaining a positive sign. The numerical calculation of glow discharge is presented, showing a positive space charge in the negative glow under conditions, where a one-dimensional model of the discharge would predict a negative space charge.

  2. Cesium injection system for negative ion duoplasmatrons

    DOE Patents [OSTI]

    Kobayashi, Maasaki (Oho, JA); Prelec, Krsto (Setauket, NY); Sluyters, Theodorus J (East Patchogue, NY)

    1978-01-01

    Longitudinally extending, foraminous cartridge means having a cylindrical side wall forming one flat, circular, tip end surface and an opposite end; an open-ended cavity, and uniformly spaced orifices for venting the cavity through the side wall in the annulus of a plasma ring for uniformly ejecting cesium for coating the flat, circular, surface. To this end, the cavity is filled with a cesium containing substance and attached to a heater in a hollow-discharge duoplasmatron. By coating the flat circular surface with a uniform monolayer of cesium and locating it in an electrical potential well at the end of a hollow-discharge, ion duoplasmatron source of an annular hydrogen plasma ring, the negative hydrogen production from the duoplasmatron is increased. The negative hydrogen is produced on the flat surface of the cartridge and extracted by the electrical potential well along a trajectory coaxial with the axis of the plasma ring.

  3. Structures with negative index of refraction

    DOE Patents [OSTI]

    Soukoulis, Costas M.; Zhou, Jiangfeng; Koschny, Thomas; Zhang, Lei; Tuttle, Gary

    2011-11-08

    The invention provides simplified negative index materials (NIMs) using wire-pair structures, 4-gap single ring split-ring resonator (SRR), fishnet structures and overleaf capacitor SRR. In the wire-pair arrangement, a pair of short parallel wires and continuous wires are used. In the 4-gap single-ring SRR, the SRRs are centered on the faces of a cubic unit cell combined with a continuous wire type resonator. Combining both elements creates a frequency band where the metamaterial is transparent with simultaneously negative .di-elect cons. and .mu.. In the fishnet structure, a metallic mesh on both sides of the dielectric spacer is used. The overleaf capacitor SRR changes the gap capacities to small plate capacitors by making the sections of the SRR ring overlap at the gaps separated by a thin dielectric film. This technique is applicable to conventional SRR gaps but it best deploys for the 4-gap single-ring structures.

  4. Positive and Negative Electrodes: Novel and Optimized Materials...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Positive and Negative Electrodes: Novel and Optimized Materials Positive and Negative Electrodes: Novel and Optimized Materials 2010 DOE Vehicle Technologies and Hydrogen Programs...

  5. California Policy Stimulates Carbon Negative CNG for Heavy Duty...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    California Policy Stimulates Carbon Negative CNG for Heavy Duty Trucks California Policy Stimulates Carbon Negative CNG for Heavy Duty Trucks Describes system for fueling truck ...

  6. Negative Effective Gravity in Water Waves by Periodic Resonator...

    Office of Scientific and Technical Information (OSTI)

    Negative Effective Gravity in Water Waves by Periodic Resonator Arrays Prev Next Title: Negative Effective Gravity in Water Waves by Periodic Resonator Arrays Authors: Hu,...

  7. Single-resonator double-negative metamaterial

    DOE Patents [OSTI]

    Warne, Larry K.; Basilio, Lorena I.; Langston, William L.; Johnson, William A.; Ihlefeld, Jon; Ginn, III, James C.; Clem, Paul G.; Sinclair, Michael B.

    2016-06-21

    Resonances can be tuned in dielectric resonators in order to construct single-resonator, negative-index metamaterials. For example, high-contrast inclusions in the form of metallic dipoles can be used to shift the first electric resonance down (in frequency) to the first magnetic resonance, or alternatively, air splits can be used to shift the first magnetic resonance up (in frequency) near the first electric resonance. Degenerate dielectric designs become especially useful in infrared- or visible-frequency applications where the resonator sizes associated with the lack of high-permittivity materials can become of sufficient size to enable propagation of higher-order lattice modes in the resulting medium.

  8. The production and destruction of negative ions

    SciTech Connect (OSTI)

    Pegg, D.J.

    1993-01-01

    Single photon absorption-single electron detachment from few-electron atomic negative ions was studied. A crossed beam apparatus is being used to perform energy- and angle-resolved photoelectron spectroscopic measurements following photodetachment. Forward-directed electrons were collected and energy analyzed. The kinetic energies and yields of the photoelectrons were obtained by fitting the spectral peaks to Gaussian functions. Electron affinities, asymmetry parameters and cross sections are determined from these measurements. A ratio method in which the cross section for the ion of interest is measured relative to that of a reference ion was used. The study of the photodetachment of Li[sup [minus

  9. Fact #917: March 21, 2016 Work Truck Daily Idle Time by Industry - Dataset

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    | Department of Energy 7: March 21, 2016 Work Truck Daily Idle Time by Industry - Dataset Fact #917: March 21, 2016 Work Truck Daily Idle Time by Industry - Dataset Excel file and dataset for Work Truck Daily Idle Time by Industry fotw#917_web.xlsx (15.85 KB) More Documents & Publications Fact #916: March 14, 2016 Fuel Savings/Emissions Reduction was the Top Reason Cited by Truck Fleet Management for Adopting Idle Reduction Technologies - Dataset Fact #833: August 11, 2014 Fuel Economy

  10. Development of versatile multiaperture negative ion sources

    SciTech Connect (OSTI)

    Cavenago, M.; Minarello, A.; Sattin, M.; Serianni, G.; Antoni, V.; Bigi, M.; Pasqualotto, R.; Recchia, M.; Veltri, P.; Agostinetti, P.; Barbisan, M.; Baseggio, L.; Cervaro, V.; Degli Agostini, F.; Franchin, L.; Laterza, B.; Ravarotto, D.; Rossetto, F.; Zaniol, B.; Zucchetti, S.; and others

    2015-04-08

    Enhancement of negative ion sources for production of large ion beams is a very active research field nowadays, driven from demand of plasma heating in nuclear fusion devices and accelerator applications. As a versatile test bench, the ion source NIO1 (Negative Ion Optimization 1) is being commissioned by Consorzio RFX and INFN. The nominal beam current of 135?mA at ?60?kV is divided into 9 beamlets, with multiaperture extraction electrodes. The plasma is sustained by a 2?MHz radiofrequency power supply, with a standard matching box. A High Voltage Deck (HVD) placed inside the lead shielding surrounding NIO1 contains the radiofrequency generator, the gas control, electronics and power supplies for the ion source. An autonomous closed circuit water cooling system was installed for the whole system, with a branch towards the HVD, using carefully optimized helical tubing. Insulation transformer is installed in a nearby box. Tests of several magnetic configurations can be performed. Status of experiments, measured spectra and plasma luminosity are described. Upgrades of magnetic filter, beam calorimeter and extraction grid and related theoretical issues are reviewed.

  11. Negative ion extraction from hydrogen plasma bulk

    SciTech Connect (OSTI)

    Oudini, N.; Taccogna, F.; Minelli, P.

    2013-10-15

    A two-dimensional particle-in-cell/Monte Carlo collision model has been developed and used to study low electronegative magnetized hydrogen plasma. A configuration characterized by four electrodes is used: the left electrode is biased at V{sub l} = −100 V, the right electrode is grounded, while the upper and lower transversal electrodes are biased at an intermediate voltage V{sub ud} between 0 and −100 V. A constant and homogeneous magnetic field is applied parallel to the lateral (left/right) electrodes. It is shown that in the magnetized case, the bulk plasma potential is close to the transversal electrodes bias inducing then a reversed sheath in front of the right electrode. The potential drop within the reversed sheath is controlled by the transversal electrodes bias allowing extraction of negative ions with a significant reduction of co-extracted electron current. Furthermore, introducing plasma electrodes, between the transversal electrodes and the right electrode, biased with a voltage just above the plasma bulk potential, increases the negative ion extracted current and decreases significantly the co-extracted electron current. The physical mechanism on basis of this phenomenon has been discussed.

  12. Negative hydrogen ion yields at plasma grid surface in a negative hydrogen ion source

    SciTech Connect (OSTI)

    Wada, M.; Kenmotsu, T.; Sasao, M.

    2015-04-08

    Negative hydrogen (H{sup ?}) ion yield from the plasma grid due to incident hydrogen ions and neutrals has been evaluated with the surface collision cascade model, ACAT (Atomic Collision in Amorphous Target) coupled to a negative surface ionization models. Dependence of negative ion fractions upon the velocity component normal to the surface largely affect the calculation results of the final energy and angular distributions of the H{sup ?} ions. The influence is particularly large for H{sup ?} ions desorbed from the surface due to less than several eV hydrogen particle implact. The present calculation predicts that H{sup ?} ion yield can be maximized by setting the incident angle of hydrogen ions and neutrals to be 65 degree. The Cs thickness on the plasma grid should also affect the yields and mean energies of surface produced H{sup ?} ions by back scattering and ion induced desorption processes.

  13. Study of global daily solar radiation and its relation to sunshine duration in Bahrain

    SciTech Connect (OSTI)

    Al-Sadah, F.H.; Ragab, F.M. )

    1991-01-01

    The regression coefficients a and b of Angstrom type correlation for the monthly daily average global solar radiation have been determined. The two constants a and b have been derived for different months during the period 1983-1987. The clearness index (H/H{sub 0}) based on predicted and measured values of global daily solar radiation is presented for different seasons of the year. The study depicts the various astronomical and meteorological parameters affecting the global radiation in Bahrain.

  14. Production of intense negative hydrogen beams with polarized nuclei by selective neutralization of cold negative ions

    DOE Patents [OSTI]

    Hershcovitch, A.

    1984-02-13

    A process for selectively neutralizing H/sup -/ ions in a magnetic field to produce an intense negative hydrogen ion beam with spin polarized protons. Characteristic features of the process include providing a multi-ampere beam of H/sup -/ ions that are

  15. Negative ion source with external RF antenna

    DOE Patents [OSTI]

    Leung, Ka-Ngo; Hahto, Sami K.; Hahto, Sari T.

    2007-02-13

    A radio frequency (RF) driven plasma ion source has an external RF antenna, i.e. the RF antenna is positioned outside the plasma generating chamber rather than inside. The RF antenna is typically formed of a small diameter metal tube coated with an insulator. An external RF antenna assembly is used to mount the external RF antenna to the ion source. The RF antenna tubing is wound around the external RF antenna assembly to form a coil. The external RF antenna assembly is formed of a material, e.g. quartz, which is essentially transparent to the RF waves. The external RF antenna assembly is attached to and forms a part of the plasma source chamber so that the RF waves emitted by the RF antenna enter into the inside of the plasma chamber and ionize a gas contained therein. The plasma ion source is typically a multi-cusp ion source. A converter can be included in the ion source to produce negative ions.

  16. Threshold photodetachment spectroscopy of negative ions

    SciTech Connect (OSTI)

    Kitsopoulos, T.N.

    1991-12-01

    This thesis is concerned with the development and application of high resolution threshold photodetachment spectroscopy of negative ions. Chapter I deals with the principles of our photodetachment technique, and in chapter II a detailed description of the apparatus is presented. The threshold photodetachment spectra of I{sup {minus}}, and SH{sup {minus}}, presented in the last sections of chapter II, indicated that a resolution of 3 cm{sup {minus}1} can be achieved using our technique. In chapter III the threshold photodetachment spectroscopy study of the transition state region of I + HI and I + Di reactions is discussed. Our technique probes the transition state region directly, and the results of our study are the first unambiguous observations of reactive resonances in a chemical reaction. Chapters IV, V and VI are concerned with the spectroscopy of small silicon and carbon clusters. From our spectra we were able to assign electronic state energies and vibrational frequencies for the low lying electronics states of Si{sub n} (n=2,3,4), C{sub 5} and their corresponding anions.

  17. Negative Electrodes Improve Safety in Lithium Cells and Batteries | Argonne

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    National Laboratory Negative Electrodes Improve Safety in Lithium Cells and Batteries Technology available for licensing: Enhanced stability at a lower cost Lowers cost for enhanced stability capability. A new class of intermetallic material for the negative electrode that offers a significantly higher volumetric and gravimetric capacity and improves battery stability and safety. PDF icon negative_electrodes

  18. Application of Markov chain model to daily maximum temperature for thermal comfort in Malaysia

    SciTech Connect (OSTI)

    Nordin, Muhamad Asyraf bin Che; Hassan, Husna

    2015-10-22

    The Markov chain’s first order principle has been widely used to model various meteorological fields, for prediction purposes. In this study, a 14-year (2000-2013) data of daily maximum temperatures in Bayan Lepas were used. Earlier studies showed that the outdoor thermal comfort range based on physiologically equivalent temperature (PET) index in Malaysia is less than 34°C, thus the data obtained were classified into two state: normal state (within thermal comfort range) and hot state (above thermal comfort range). The long-run results show the probability of daily temperature exceed TCR will be only 2.2%. On the other hand, the probability daily temperature within TCR will be 97.8%.

  19. EIA - Daily Report 9/12/05 - Hurricane Katrina's Impact on U.S. Oil &

    U.S. Energy Information Administration (EIA) Indexed Site

    Natural Gas Energy Markets 2, 5:00 pm According to the Minerals Management Service (MMS), as of 11:30 September 12, Gulf of Mexico oil production was reduced by 860,636 barrels per day as a result of Hurricane Katrina, equivalent to 57.38 percent of daily Gulf of Mexico oil production (which is 1.5 million barrels per day). The MMS also reported that 3.784 billion cubic feet per day of natural gas production was shut in, equivalent to 37.84 percent of daily Gulf of Mexico natural gas

  20. EIA - Daily Report 9/13/05 - Hurricane Katrina's Impact on U.S. Oil &

    U.S. Energy Information Administration (EIA) Indexed Site

    Natural Gas Energy Markets Tuesday, September 13, 4:00 pm According to the Minerals Management Service (MMS), as of 11:30 September 12, Gulf of Mexico oil production was reduced by 846,720 barrels per day as a result of Hurricane Katrina, equivalent to 56.45 percent of daily Gulf of Mexico oil production (which had been1.5 million barrels per day). The MMS also reported that 3.720 billion cubic feet per day of natural gas production was shut in, equivalent to 37.20 percent of daily Gulf of

  1. EIA - Daily Report 9/14/05 - Hurricane Katrina's Impact on U.S. Oil &

    U.S. Energy Information Administration (EIA) Indexed Site

    Natural Gas Energy Markets Wednesday, September 14, 4:00 pm According to the Minerals Management Service (MMS), as of 11:30 September 14, Gulf of Mexico oil production was reduced by 843,725 barrels per day as a result of Hurricane Katrina, equivalent to 56.25 percent of daily Gulf of Mexico oil production (which had been 1.5 million barrels per day). The MMS also reported that 3.518 billion cubic feet per day of natural gas production was shut in, equivalent to 35.18 percent of daily Gulf

  2. EIA - Daily Report 9/15/05 - Hurricane Katrina's Impact on U.S. Oil &

    U.S. Energy Information Administration (EIA) Indexed Site

    Natural Gas Energy Markets Thursday, September 15, 3:00 pm According to the Minerals Management Service (MMS), as of 11:30 September 15, Gulf of Mexico oil production was reduced by 842,091 barrels per day as a result of Hurricane Katrina, equivalent to 56.14 percent of daily Gulf of Mexico oil production (which had been 1.5 million barrels per day). The MMS also reported that 3.411 billion cubic feet per day of natural gas production was shut in, equivalent to 34.11 percent of daily Gulf of

  3. EIA - Daily Report 9/7/05 - Hurricane Katrina's Impact on U.S. Oil &

    U.S. Energy Information Administration (EIA) Indexed Site

    Natural Gas Energy Markets 7, 3:00 pm According to the Minerals Management Service (MMS), as of 11:30 September 7, Gulf of Mexico oil production was reduced by 861,000 barrels per day as a result of Hurricane Katrina, equivalent to 57.37 percent of daily Gulf of Mexico oil production (which is 1.5 million barrels per day). The MMS also reported that 4.0360 billion cubic feet per day of natural gas production was shut in, equivalent to 40.36 percent of daily Gulf of Mexico natural gas

  4. Pool daily fuel scheduling. Volume 1: technical manual. Final Report, February 1981

    SciTech Connect (OSTI)

    Pang, C.K.; Mikolinnas, T.A.; Reppen, N.D.; Ringlee, R.J.; Wollenberg, B.F.

    1981-02-01

    The results and efforts of research and development of methods for daily fuel scheduling performed under EPRI Project RP 1048-5 by Power Technologies, Inc. (PTI) are reported in three volumes: Technical Manual, Programming Manual, and Program Listings. Daily fuel scheduling involves the scheduling and dispatching of generating facilities to meet all system loads and operating requirements for periods ranging from a day to a week. Daily fuel scheduling and computer requirements are defined. The scheduling problem is formulated as a mixed-integer linear programming (MILP) optimization problem in which the total system operating cost is minimized. A potentially practical scheduling procedure, based on a combination of search and MILP approaches, was proposed; these two approaches were investigated, coded in FORTRAN and tested individually. This volume of the report (Volume 1) is the Technical Manual and contains the main body of the report, which includes descriptions and results for two approaches to the daily fuel scheduling problem: Search Approach and Mixed Integer Linear Programming (MILP) Approach. Prototype computer programs on these approaches have been coded in FORTRAN for testing and evaluation purposes using PTI in-house PRIME time-sharing computer.

  5. Virginia Senate Approves Budget Deal to Include Money for FEL (Daily Press)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    | Jefferson Lab Virginia Senate Approves Budget Deal to Include Money for FEL (Daily Press) External Link: http://articles.dailypress.com/2012-04-18/news/dp-nws-general-assembly-budget-da... By jlab_admin on Wed, 2012-04-18

  6. Newport News School Board Member Hosting Town Hall Thursday (Daily Press) |

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Jefferson Lab Newport News School Board Member Hosting Town Hall Thursday (Daily Press) External Link: http://articles.dailypress.com/2012-03-05/news/dp-nws-ednotebook-0305-20120304_1... By jlab_admin on Tue, 2012-03-06

  7. Daily snow depth measurements from 195 stations in the United States

    SciTech Connect (OSTI)

    Allison, L.J.; Easterling, D.R.; Jamason, P.; Bowman, D.P.; Hughes, P.Y.; Mason, E.H.

    1997-02-01

    This document describes a database containing daily measurements of snow depth at 195 National Weather Service (NWS) first-order climatological stations in the United States. The data have been assembled and made available by the National Climatic Data Center (NCDC) in Asheville, North Carolina. The 195 stations encompass 388 unique sampling locations in 48 of the 50 states; no observations from Delaware or Hawaii are included in the database. Station selection criteria emphasized the quality and length of station records while seeking to provide a network with good geographic coverage. Snow depth at the 388 locations was measured once per day on ground open to the sky. The daily snow depth is the total depth of the snow on the ground at measurement time. The time period covered by the database is 1893--1992; however, not all station records encompass the complete period. While a station record ideally should contain daily data for at least the seven winter months (January through April and October through December), not all stations have complete records. Each logical record in the snow depth database contains one station`s daily data values for a period of one month, including data source, measurement, and quality flags.

  8. Jefferson Lab: Laser gun to eventually shoot down missiles (Daily Press) |

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Jefferson Lab Jefferson Lab: Laser gun to eventually shoot down missiles (Daily Press) External Link: http://articles.dailypress.com/2011-02-21/news/dp-nws-jefferson-lab-20110221_1_j... By jlab_admin on Mon, 2011-02-21

  9. Daily air pollution effects on children's respiratory symptoms and peak expiratory flow

    SciTech Connect (OSTI)

    Vedal, S.; Schenker, M.B.; Munoz, A.; Samet, J.M.; Batterman, S.; Speizer, F.E.

    1987-06-01

    To identify acute respiratory health effects associated with air pollution due to coal combustion, a subgroup of elementary school-aged children was selected from a large cross-sectional study and followed daily for eight months. Children were selected to obtain three equal-sized groups: one without respiratory symptoms, one with symptoms of persistent wheeze, and one with cough or phlegm production but without persistent wheeze. Parents completed a daily diary of symptoms from which illness constellations of upper respiratory illness (URI) and lower respiratory illness (LRI) and the symptom of wheeze were derived. Peak expiratory flow rate (PEFR) was measured daily for nine consecutive weeks during the eight-month study period. Maximum hourly concentrations of sulfur dioxide, nitrogen dioxide, ozone, and coefficient of haze for each 24-hour period, as well as minimum hourly temperature, were correlated with daily URI, LRI, wheeze, and PEFR using multiple regression models adjusting for illness occurrence or level of PEFR on the immediately preceding day. Respiratory illness on the preceding day was the most important predictor of current illness. A drop in temperature was associated with increased URI and LRI but not with increased wheeze or with a decrease in level of PEFR. No air pollutant was strongly associated with respiratory illness or with level of PEFR, either in the group of children as a whole, or in either of the symptomatic subgroups; the pollutant concentrations observed, however, were uniformly lower than current ambient air quality standards.

  10. JLab Nanotube Research Leads To Newport News Start-Up (Daily Press) |

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Jefferson Lab Nanotube Research Leads To Newport News Start-Up (Daily Press) External Link: http://articles.dailypress.com/2012-08-03/news/dp-nws-cp-jefferson-lab-spinoff-2... By jlab_admin on Fri, 2012-08-03

  11. JLab's Walt Akers: from Fife and Drum to Windmill (Daily Press) | Jefferson

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Lab Walt Akers: from Fife and Drum to Windmill (Daily Press) External Link: http://articles.dailypress.com/2012-03-08/news/dp-tsq-ypq-five-questions-0308-20... By jlab_admin on Thu, 2012-03-08

  12. United States Historical Climatology Network Daily Temperature and Precipitation Data (1871-1997)

    SciTech Connect (OSTI)

    Easterling, D.R.

    2002-10-28

    This document describes a database containing daily observations of maximum and minimum temperature, precipitation amount, snowfall amount, and snow depth from 1062 observing stations across the contiguous US. This database is an expansion and update of the original 138-station database previously released by the Carbon Dioxide Information Analysis Center (CDIAC) as CDIAC numeric data package NDP-042. These 1062 stations are a subset of the 1221-station US Historical Climatology Network (HCN), a monthly database compiled by the National Climatic Data Center (Asheville, North Carolina) that has been widely used in analyzing US climate. Data from 1050 of these daily records extend into the 1990s, while 990 of these extend through 1997. Most station records are essentially complete for at least 40 years; the latest beginning year of record is 1948. Records from 158 stations begin prior to 1900, with that of Charleston, South Carolina beginning the earliest (1871). The daily resolution of these data makes them extremely valuable for studies attempting to detect and monitor long-term climatic changes on a regional scale. Studies using daily data may be able to detect changes in regional climate that would not be apparent from analysis of monthly temperature and precipitation data. Such studies may include analyses of trends in maximum and minimum temperatures, temperature extremes, daily temperature range, precipitation ''event size'' frequency, and the magnitude and duration of wet and dry periods. The data are also valuable in areas such as regional climate model validation and climate change impact assessment. This database is available free of charge from CDIAC as a numeric data package (NDP).

  13. Negative ion source with hollow cathode discharge plasma

    DOE Patents [OSTI]

    Hershcovitch, A.; Prelec, K.

    1980-12-12

    A negative ion source of the type where negative ions are formed by bombarding a low-work-function surface with positive ions and neutral particles from a plasma, wherein a highly ionized plasma is injected into an anode space containing the low-work-function surface is described. The plasma is formed by hollow cathode discharge and injected into the anode space along the magnetic field lines. Preferably, the negative ion source is of the magnetron type.

  14. Negative ion source with hollow cathode discharge plasma

    DOE Patents [OSTI]

    Hershcovitch, Ady; Prelec, Krsto

    1983-01-01

    A negative ion source of the type where negative ions are formed by bombarding a low-work-function surface with positive ions and neutral particles from a plasma, wherein a highly ionized plasma is injected into an anode space containing the low-work-function surface. The plasma is formed by hollow cathode discharge and injected into the anode space along the magnetic field lines. Preferably, the negative ion source is of the magnetron type.

  15. Production of negative hydrogen ions on metal grids

    SciTech Connect (OSTI)

    Oohara, W.; Maetani, Y.; Takeda, Takashi; Takeda, Toshiaki; Yokoyama, H.; Kawata, K.

    2015-03-15

    Negative hydrogen ions are produced on a nickel grid with positive-ion irradiation. In order to investigate the production mechanism, a copper grid without the chemisorption of hydrogen atoms and positive helium ions without negative ionization are used for comparison. Positive hydrogen ions reflected on the metal surface obtain two electrons from the surface and become negatively ionized. It is found that the production yield of negative ions by desorption ionization of chemisorbed hydrogen atoms seems to be small, and the production is a minor mechanism.

  16. Structures with Negative Refractive Index for Applications in...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    This Return to Search Structures with Negative Refractive Index for Applications in Optics and Nanophotonics Ames Laboratory Contact AMES About This Technology Technology...

  17. Recovery Efficiency, False Negative Rate, and Limit of Detection...

    Office of Scientific and Technical Information (OSTI)

    Recovery Efficiency, False Negative Rate, and Limit of Detection Performance of a Validated Macrofoam-Swab Sampling Method with Low Surface Concentrations of Two Bacillus anthracis...

  18. Negative ion production and beam extraction processes in a large...

    Office of Scientific and Technical Information (OSTI)

    Spatial density and flow distributions of negative hydrogen ions (Hsup -) and positive hydrogen ions together with those of electrons are investigated with a 4-pin probe and a ...

  19. Negative Electrodes Improve Safety in Lithium Cells and Batteries...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Negative Electrodes Improve Safety in Lithium Cells and Batteries Technology available for licensing: Enhanced stability at a lower cost Lowers cost for enhanced stability ...

  20. Daymet: Daily Surface Weather Data on a 1-km Grid for North America, Version 2.

    SciTech Connect (OSTI)

    Thornton, Peter E; Thornton, Michele M; Mayer, Benjamin W; Wilhelmi, Nate; Wei, Yaxing; Devarakonda, Ranjeet; Cook, Robert B

    2014-01-01

    More information: http://daymet.ornl.gov Presenter: Ranjeet Devarakonda Environmental Sciences Division Oak Ridge National Laboratory (ORNL) Daymet: Daily Surface Weather Data and Climatological Summaries provides gridded estimates of daily weather parameters for North America, including daily continuous surfaces of minimum and maximum temperature, precipitation occurrence and amount, humidity, shortwave radiation, snow water equivalent, and day length. The current data product (Version 2) covers the period January 1, 1980 to December 31, 2013 [1]. The prior product (Version 1) only covered from 1980-2008. Data are available on a daily time step at a 1-km x 1-km spatial resolution in Lambert Conformal Conic projection with a spatial extent that covers the conterminous United States, Mexico, and Southern Canada as meteorological station density allows. Daymet data can be downloaded from 1) the ORNL Distributed Active Archive Center (DAAC) search and order tools (http://daac.ornl.gov/cgi-bin/cart/add2cart.pl?add=1219) or directly from the DAAC FTP site (http://daac.ornl.gov/cgi-bin/dsviewer.pl?ds_id=1219) and 2) the Single Pixel Tool [2] and THREDDS (Thematic Real-time Environmental Data Services) Data Server [3]. The Single Pixel Data Extraction Tool allows users to enter a single geographic point by latitude and longitude in decimal degrees. A routine is executed that translates the (lon, lat) coordinates into projected Daymet (x,y) coordinates. These coordinates are used to access the Daymet database of daily-interpolated surface weather variables. Daily data from the nearest 1 km x 1 km Daymet grid cell are extracted from the database and formatted as a table with one column for each Daymet variable and one row for each day. All daily data for selected years are returned as a single (long) table, formatted for display in the browser window. At the top of this table is a link to the same data in a simple comma-separated text format, suitable for import into a

  1. Pool daily fuel scheduling. Volume 2: programming manual. Final report, February 1981

    SciTech Connect (OSTI)

    Pang, C.K.; Mikolinnas, T.A.

    1981-02-01

    The results and efforts of research and development of methods for daily fuel scheduling performed under EPRI Project RP 1048-5 by Power Technologies, Inc. (PTI) are reported in three volumes: Technical Manual; Programming Manual and Program Listings. Daily fuel scheduling involves the scheduling and dispatching of generating facilities to meet all system loads and operating requirements for periods ranging from a day to a week. Daily fuel scheduling and computer requirements are defined. The scheduling problem is formulated as a mixed-integer linear programming (MILP) optimization problem in which the total system operating cost is minimized. A potentially practical scheduling procedure, based on a combination of search and MILP approaches, was proposed; these two approaches were investigated, coded in FORTRAN and tested individually. Tests using the New York Power Pool system show that the search approach may produce potential savings for fuel scheduling approaches. Additional efforts are needed to make the MILP approach practical. Finally, a number of special scheduling problems have been identified and recommended for future work. This volume of the report (Volume 2) is the Programming Manual which describes the organization and structure of the programs. Layout and function of data files, sample outputs and test data are also presented. Program organization and data for the search and MILP approaches are given. Preliminary test results, system data descriptions and sample outputs for the search approach are included in the appendices.

  2. SU-E-J-153: MRI Based, Daily Adaptive Radiotherapy for Rectal Cancer: Contour Adaptation

    SciTech Connect (OSTI)

    Kleijnen, J; Burbach, M; Verbraeken, T; Weggers, R; Zoetelief, A; Reerink, O; Lagendijk, J; Raaymakers, B; Asselen, B

    2014-06-01

    Purpose: A major hurdle in adaptive radiotherapy is the adaptation of the planning MRI's delineations to the daily anatomy. We therefore investigate the accuracy and time needed for online clinical target volume (CTV) adaptation by radiation therapists (RTT), to be used in MRI-guided adaptive treatments on a MRI-Linac (MRL). Methods: Sixteen patients, diagnosed with early stage rectal cancer, underwent a T2-weighted MRI prior to each fraction of short-course radiotherapy, resulting in 4–5 scans per patient. On these scans, the CTV was delineated according to guidelines by an experienced radiation oncologist (RO) and considered to be the gold standard. For each patient, the first MRI was considered as the planning MRI and matched on bony anatomy to the 3–4 daily MRIs. The planning MRI's CTV delineation was rigidly propagated to the daily MRI scans as a proposal for adaptation. Three RTTs in training started the adaptation of the CTV conform guidelines, after a two hour training lecture and a two patient (n=7) training set. To assess the inter-therapist variation, all three RTTs altered delineations of 3 patients (n=12). One RTT altered the CTV delineations (n=53) of the remaining 11 patients. Time needed for adaptation of the CTV to guidelines was registered.As a measure of agreement, the conformity index (CI) was determined between the RTTs' delineations as a group. Dice similarity coefficients were determined between delineations of the RTT and the RO. Results: We found good agreement between RTTs' and RO's delineations (average Dice=0.91, SD=0.03). Furthermore, the inter-observer agreement between the RTTs was high (average CI=0.94, SD=0.02). Adaptation time reduced from 10:33 min (SD= 3:46) to 2:56 min (SD=1:06) between the first and last ten delineations, respectively. Conclusion: Daily CTV adaptation by RTTs, seems a feasible and safe way to introduce daily, online MRI-based plan adaptation for a MRL.

  3. Production of intense negative hydrogen beams with polarized nuclei by selective neutralization of negative ions

    DOE Patents [OSTI]

    Hershcovitch, Ady

    1987-01-01

    A process for selectively neutralizing H.sup.- ions in a magnetic field to produce an intense negative hydrogen ion beam with spin polarized protons. Characteristic features of the process include providing a multi-ampere beam of H.sup.- ions that are intersected by a beam of laser light. Photodetachment is effected in a uniform magnetic field that is provided around the beam of H.sup.- ions to spin polarize the H.sup.- ions and produce first and second populations or groups of ions, having their respective proton spin aligned either with the magnetic field or opposite to it. The intersecting beam of laser light is directed to selectively neutralize a majority of the ions in only one population, or given spin polarized group of H.sup.- ions, without neutralizing the ions in the other group thereby forming a population of H.sup.- ions each of which has its proton spin down, and a second group or population of H.sup.o atoms having proton spin up. Finally, the two groups of ions are separated from each other by magnetically bending the group of H.sup.- ions away from the group of neutralized ions, thereby to form an intense H.sup.- ion beam that is directed toward a predetermined objective.

  4. Negative particle planar and axial channeling and channeling collimation

    SciTech Connect (OSTI)

    Carrigan, Richard A., Jr.; /Fermilab

    2009-12-01

    While information exists on high energy negative particle channeling there has been little study of the challenges of negative particle bending and channeling collimation. Partly this is because negative dechanneling lengths are relatively much shorter. Electrons are not particularly useful for investigating negative particle channeling effects because their material interactions are dominated by channeling radiation. Another important factor is that the current central challenge in channeling collimation is the proton-proton Large Hadron Collider (LHC) where both beams are positive. On the other hand in the future the collimation question might reemerge for electon-positron or muon colliders. Dechanneling lengths increase at higher energies so that part of the negative particle experimental challenge diminishes. In the article different approaches to determining negative dechanneling lengths are reviewed. The more complicated case for axial channeling is also discussed. Muon channeling as a tool to investigate dechanneling is also discussed. While it is now possible to study muon channeling it will probably not illuminate the study of negative dechanneling.

  5. Noise reduction in negative-ion quadrupole mass spectrometry

    DOE Patents [OSTI]

    Chastagner, Philippe

    1993-01-01

    A quadrupole mass spectrometer (QMS) system having an ion source, quadrupole mass filter, and ion collector/recorder system. A weak, transverse magnetic field and an electron collector are disposed between the quadrupole and ion collector. When operated in negative ion mode, the ion source produces a beam of primarily negatively-charged particles from a sample, including electrons as well as ions. The beam passes through the quadrupole and enters the magnetic field, where the electrons are deflected away from the beam path to the electron collector. The negative ions pass undeflected to the ion collector where they are detected and recorded as a mass spectrum.

  6. Noise reduction in negative-ion quadrupole mass spectrometry

    DOE Patents [OSTI]

    Chastagner, P.

    1993-04-20

    A quadrupole mass spectrometer (QMS) system is described having an ion source, quadrupole mass filter, and ion collector/recorder system. A weak, transverse magnetic field and an electron collector are disposed between the quadrupole and ion collector. When operated in negative ion mode, the ion source produces a beam of primarily negatively-charged particles from a sample, including electrons as well as ions. The beam passes through the quadrupole and enters the magnetic field, where the electrons are deflected away from the beam path to the electron collector. The negative ions pass undeflected to the ion collector where they are detected and recorded as a mass spectrum.

  7. California Policy Stimulates Carbon Negative CNG for Heavy Duty Trucks |

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Department of Energy California Policy Stimulates Carbon Negative CNG for Heavy Duty Trucks California Policy Stimulates Carbon Negative CNG for Heavy Duty Trucks Describes system for fueling truck fleet with biomethane generated from anaerobic digestion of organic waste it collects p-10_edgar.pdf (364.34 KB) More Documents & Publications Advanced Natural Gas Engine Technology for Heavy Duty Vehicles Technical Workshop: Annual Merit Review Lessons Learned on Alternative Transportation

  8. Negative ion source with low temperature transverse divergence optical system

    DOE Patents [OSTI]

    Whealton, John H.; Stirling, William L.

    1986-01-01

    A negative ion source is provided which has extremely low transverse divergence as a result of a unique ion focusing system in which the focal line of an ion beam emanating from an elongated, concave converter surface is outside of the ion exit slit of the source and the path of the exiting ions. The beam source operates with a minimum ion temperature which makes possible a sharply focused (extremely low transverse divergence) ribbon like negative ion beam.

  9. Negative ion source with low temperature transverse divergence optical system

    DOE Patents [OSTI]

    Whealton, J.H.; Stirling, W.L.

    1985-03-04

    A negative ion source is provided which has extremely low transverse divergence as a result of a unique ion focusing system in which the focal line of an ion beam emanating from an elongated, concave converter surface is outside of the ion exit slit of the source and the path of the exiting ions. The beam source operates with a minimum ion temperature which makes possible a sharply focused (extremely low transverse divergence) ribbon like negative ion beam.

  10. EIA - Daily Report 9/16/05 - Hurricane Katrina's Impact on U.S. Oil &

    U.S. Energy Information Administration (EIA) Indexed Site

    Natural Gas Energy Markets 16, 4:00 pm Hurricane Katrina in Perspective (see figures below) While the peak crude oil production loss from Hurricane Katrina was similar to Hurricane Ivan last year and even less than Hurricane Dennis earlier this year, the pace of restoration is expected to be much more similar to Hurricane Ivan than any of the other recent hurricanes. For example, while the peak daily loss in crude oil production during Hurricane Dennis was slightly more than suffered

  11. EIA - Daily Report 9/19/05 - Hurricane Katrina's Impact on U.S. Oil &

    U.S. Energy Information Administration (EIA) Indexed Site

    Natural Gas Energy Markets Monday, September 19, 5:00 pm Hurricane Katrina in Perspective (see figures below). While the peak crude oil production loss from Hurricane Katrina was similar to 2004's Hurricane Ivan and even less than Hurricane Dennis earlier this year, the pace of restoration is expected to be much more similar to Hurricane Ivan than any of the other recent hurricanes. For example, while the peak daily loss in crude oil production during Hurricane Dennis was slightly more than

  12. Daily diaries of respiratory symptoms and air pollution: Methodological issues and results

    SciTech Connect (OSTI)

    Schwartz, J. ); Wypij, D.; Dockery D.; Ware, J.; Spengler, J.; Ferris, B. Jr. ); Zeger, S. )

    1991-01-01

    Daily diaries of respiratory symptoms are a powerful technique for detecting acute effects of air pollution exposure. While conceptually simple, these diary studies can be difficult to analyze. The daily symptom rates are highly correlated, even after adjustment for covariates, and this lack of independence must be considered in the analysis. Possible approaches include the use of incidence instead of prevalence rates and autoregressive models. Heterogeneity among subjects also induces dependencies in the data. These can be addressed by stratification and by two-stage models such as those developed by Korn and Whittemore. These approaches have been applied to two data sets: a cohort of school children participating in the Harvard Six Cities Study and a cohort of student nurses in Los Angeles. Both data sets provide evidence of autocorrelation and heterogeneity. Controlling for autocorrelation corrects the precision estimates, and because diary data are usually positively autocorrelated, this leads to larger variance estimates. Controlling for heterogeneity among subjects appears to increase the effect sizes for air pollution exposure. Preliminary results indicate associations between sulfur dioxide and cough incidence in children and between nitrogen dioxide and phlegm incidence in student nurses.

  13. Daily movements of female white-tailed deer relative to parturition and breeding.

    SciTech Connect (OSTI)

    Gino J. D'Angelo; Christopher E. Comer; John C. Kilgo; Cory D. Drennan; David A. Osborn; Karl V. Miller

    2005-10-01

    Abstract: To assess how white-tailed deer (Odocoileus virginianus) herd demographics influence reproductive behaviors, we examined 24-h diel movements of female whitetailed deer relative to parturition and breeding in a low-density population with a near even sex ratio at the Savannah River Site (SRS), South Carolina. We conducted a series of intensive, 24-h radio-tracking periods of 13 females during spring and fall 2002. We compared daily range (ha), rate of travel (m/h), and distance between extreme daily locations (m), among the periods of pre-parturition and post-parturition and pre-, peak-, and post-rut. From pre-parturition to post-parturition, we observed decreases in diel range size (?¢????38.2%), distance between extreme diel locations (?¢????17.0%), and diel rate of travel (?¢????18.2%). Diel range size, distance between extreme diel locations, and diel rate of travel during the pre-rut and rut exceeded those observed during post-rut. We further identified substantial increases in mobility during 12 24-h diel periods for eight females during our fall monitoring. Our data suggest that female white-tailed deer reduce mobility post-fawning following exaggerated movements during pre-parturition. Furthermore, despite a near equal sex ratio, estrous does may be required to actively seek potential mates due to low population density.

  14. Markov chain decomposition of monthly rainfall into daily rainfall: Evaluation of climate change impact

    SciTech Connect (OSTI)

    Yoo, Chulsang; Lee, Jinwook; Ro, Yonghun

    2016-01-01

    This paper evaluates the effect of climate change on daily rainfall, especially on the mean number of wet days and the mean rainfall intensity. Assuming that the mechanism of daily rainfall occurrences follows the first-order Markov chain model, the possible changes in the transition probabilities are estimated by considering the climate change scenarios. Also, the change of the stationary probabilities of wet and dry day occurrences and finally the change in the number of wet days are derived for the comparison of current (1x CO2) and 2x CO2conditions. As a result of this study, the increase or decrease in the mean number of wet days was found to be not enough to explain all of the change in monthly rainfall amounts, so rainfall intensity should also be modified. The application to the Seoul weather station in Korea shows that about 30% of the total change in monthly rainfall amount can be explained by the change in the number of wet days and the remaining 70% by the change in the rainfall intensity. That is, as an effect of climate change, the increase in the rainfall intensity could be more significant than the increase in the wet days and, thus, the risk of flood will be much highly increased.

  15. Markov chain decomposition of monthly rainfall into daily rainfall: Evaluation of climate change impact

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Yoo, Chulsang; Lee, Jinwook; Ro, Yonghun

    2016-01-01

    This paper evaluates the effect of climate change on daily rainfall, especially on the mean number of wet days and the mean rainfall intensity. Assuming that the mechanism of daily rainfall occurrences follows the first-order Markov chain model, the possible changes in the transition probabilities are estimated by considering the climate change scenarios. Also, the change of the stationary probabilities of wet and dry day occurrences and finally the change in the number of wet days are derived for the comparison of current (1x CO2) and 2x CO2conditions. As a result of this study, the increase or decrease in themore » mean number of wet days was found to be not enough to explain all of the change in monthly rainfall amounts, so rainfall intensity should also be modified. The application to the Seoul weather station in Korea shows that about 30% of the total change in monthly rainfall amount can be explained by the change in the number of wet days and the remaining 70% by the change in the rainfall intensity. That is, as an effect of climate change, the increase in the rainfall intensity could be more significant than the increase in the wet days and, thus, the risk of flood will be much highly increased.« less

  16. Magnetic Response and Negative Refractive Index of Metamaterials

    SciTech Connect (OSTI)

    Koschny, Th.; Zhou, J.; Soukoulis, C.M.

    2007-05-04

    We study the scaling of negative magnetic response of the SRR from microwave to upper THz frequencies. We show, that the linear scaling breaks down for SRR sizes below the order of 1 {micro}m. This breakdown is due to the contribution of the finite electron mass to the inductance of the effective LC oscillator. While at microwave frequencies metals can be treated as near-perfect conductors, close to optical frequencies they rather constitute lossy negative dielectrics. We also study the scaling of the losses in SRR as well as the higher order excitations or plasmon modes and their magnetic response. We discuss the non-resonant diamagnetic response of the SRR and the corresponding corrections to the shape of the frequency dependent effective permeability of the metamaterial. We discuss the connection of recently suggested alternative negative index metamaterial designs in a unified picture.

  17. Evaluation of negative ion distribution changes by image processing diagnostic

    SciTech Connect (OSTI)

    Ikeda, K. Nakano, H.; Tsumori, K.; Kisaki, M.; Nagaoka, K.; Tokuzawa, T.; Osakabe, M.; Takeiri, Y.; Kaneko, O.; Geng, S.

    2015-04-08

    Distributions of hydrogen Balmer-α (H{sub α}) intensity and its reduction behavior close to a plasma grid (PG) surface have been observed by a spectrally selective imaging system in an arc discharge type negative hydrogen ion source in National Institute for Fusion Science. H{sub α} reduction indicates a reduction of negative hydrogen ions because the mutual neutralization process between H{sup +} and H{sup −} ions causes the dominant excitation process for H{sub α} emission in the rich H{sup −} condition such as in ionic plasma. We observed a significant change in H{sub α} reduction distribution due to change in the bias voltage, which is used to suppress the electron influx. Small H{sub α} reduction in higher bias is likely because the production of negative ions is suppressed by the potential difference between the plasma and PG surface.

  18. Device for translating negative film image to a line scan

    DOE Patents [OSTI]

    Dutton, G. Wayne

    1998-05-19

    A negative film reader records high-resolution optical density changes across negative film radiographic images to allow precise image dimensions to be determined. A laser light source capable of high-resolution focusing is passed through an intensity control filter, focused by a lens, and reflected off a mirror to focus in the plane of the negative film. The light transmitted through the film is collected by a second lens and directed to a photo diode detector which senses the transmitted intensity. The output of the photo diode signal amplifier is sent to the Y-axis input of an X-Y recorder. The film sample is transported in a plane perpendicular to the beam axis by means of a slide. The film position is monitored, with the signal amplified and recorded as the X-axis on the X-Y recorder. The linear dimensions and positions of image components can be determined by direct measurement of the amplified recording.

  19. Electron energy recovery system for negative ion sources

    DOE Patents [OSTI]

    Dagenhart, W.K.; Stirling, W.L.

    1979-10-25

    An electron energy recovery system for negative ion sources is provided. The system, employing crossed electric and magnetic fields, separates the electrons from the ions as they are extracted from the ion source plasma generator and before the ions are accelerated to their full energy. With the electric and magnetic fields oriented 90/sup 0/ to each other, the electrons remain at approximately the electrical potential at which they were generated. The electromagnetic forces cause the ions to be accelerated to the full accelerating supply voltage energy while being deflected through an angle of less than 90/sup 0/. The electrons precess out of the accelerating field region into an electron recovery region where they are collected at a small fraction of the full accelerating supply energy. It is possible, by this method, to collect > 90% of the electrons extracted along with the negative ions from a negative ion source beam at < 4% of full energy.

  20. Bimolecular reaction dynamics from photoelectron spectroscopy of negative ions

    SciTech Connect (OSTI)

    Bradforth, S.E.

    1992-11-01

    The transition state region of a neutral bimolecular reaction may be experimentally investigated by photoelectron spectroscopy of an appropriate negative ion. The photoelectron spectrum provides information on the spectroscopy and dynamics of the short lived transition state and may be used to develop model potential energy surfaces that are semi-quantitative in this important region. The principles of bound [yields] bound negative ion photoelectron spectroscopy are illustrated by way of an example: a full analysis of the photoelectron bands of CN[sup [minus

  1. Photodetachment of hydrogen negative ions with screened Coulomb interaction

    SciTech Connect (OSTI)

    Zhang, Song Bin; Chen, Xiang Jun; Wang, Jian Guo; Janev, R. K.; Qu, Yi Zhi

    2010-06-15

    The effects of Coulomb interaction screening on photodetachment cross sections of hydrogen negative ions below the n =2 excitation threshold is investigated by using the R-matrix method with pseudostates. The contributions of Feshbach and shape resonances to H{sup -} photodetachment cross section are presented when screening length (D) varies from D = {infinity} to D = 4.6 a.u. It is found that the interaction screening has dramatic effects on the photodetachment cross sections of hydrogen negative ions in the photoelectron energy region around the n = 2 excitation threshold by strongly affecting the evolution of near-threshold resonances.

  2. Electrostatic plasma lens for focusing negatively charged particle beams

    SciTech Connect (OSTI)

    Goncharov, A. A.; Dobrovolskiy, A. M.; Dunets, S. M.; Litovko, I. V.; Gushenets, V. I.; Oks, E. M.

    2012-02-15

    We describe the current status of ongoing research and development of the electrostatic plasma lens for focusing and manipulating intense negatively charged particle beams, electrons, and negative ions. The physical principle of this kind of plasma lens is based on magnetic isolation electrons providing creation of a dynamical positive space charge cloud in shortly restricted volume propagating beam. Here, the new results of experimental investigations and computer simulations of wide-aperture, intense electron beam focusing by plasma lens with positive space charge cloud produced due to the cylindrical anode layer accelerator creating a positive ion stream towards an axis system is presented.

  3. Daily treatment with {alpha}-naphthoflavone enhances follicular growth and ovulation rate in the rat

    SciTech Connect (OSTI)

    Barreiro, Karina A.; Di Yorio, Maria P.; Artillo-Guida, Romina D.; Paz, Dante A.; Faletti, Alicia G.

    2011-04-01

    The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor and the first protein involved in a variety of physiological and toxicological processes, including those of xenobiotic metabolizing enzymes. AhR has been found in the ovary of many species and seems to mediate the ovarian toxicity of many environmental contaminants, which are AhR ligands. However, the role of AhR in the ovarian function is unknown. Therefore, the aim of this work was to study the action of {alpha}-naphthoflavone ({alpha}NF), known to be an AhR antagonist, on both follicular growth and ovulation. Immature Sprague-Dawley rats were daily injected intraperitoneally with {alpha}NF (0.1-80 mg/kg) or vehicle for 12 days, and primed with gonadotrophins (eCG/hCG) to induce follicular growth and ovulation. Ovaries were obtained 20 h after hCG administration. By means of immunohistochemistry, we found that the numbers of primordial, primary and antral follicles were increased in rats treated with 80 mg/kg {alpha}NF and that there were no differences with other doses. Likewise, the ovarian weight and the ovulation rate, measured by both number of oocytes within oviducts and corpora lutea in ovarian sections, were increased when the rats received either 1 or 10 mg/kg daily. Although further studies are necessary to know the mechanism of action of {alpha}NF, it is possible that the different ovarian processes can be differentially responsive to the presence of different levels of {alpha}NF, and that the same or different endogenous AhR ligands can be involved in these ovarian processes in a cell type-dependent manner.

  4. SU-D-BRF-04: Digital Tomosynthesis for Improved Daily Setup in Treatment of Liver Lesions

    SciTech Connect (OSTI)

    Armstrong, H; Jones, B; Miften, M

    2014-06-01

    Purpose: Daily localization of liver lesions with cone-beam CT (CBCT) is difficult due to poor image quality caused by scatter, respiratory motion, and the lack of radiographic contrast between the liver parenchyma and the lesion(s). Digital tomosynthesis (DTS) is investigated as a modality to improve liver visualization and lesion/parenchyma contrast for daily setup. Methods: An in-house tool was developed to generate DTS images using a point-by-point filtered back-projection method from on-board CBCT projection data. DTS image planes are generated in a user defined orientation to visualize the anatomy at various depths. Reference DTS images are obtained from forward projection of the planning CT dataset at each projection angle. The CBCT DTS image set can then be registered to the reference DTS image set as a means for localization. Contour data from the planning CT's associate RT Structure file and forward projected similarly to the planning CT data. DTS images are created for each contoured structure, which can then be overlaid onto the DTS images for organ volume visualization. Results: High resolution DTS images generated from CBCT projections show fine anatomical detail, including small blood vessels, within the patient. However, the reference DTS images generated from forward projection of the planning CT lacks this level of detail due to the low resolution of the CT voxels as compared to the pixel size in the projection images; typically 1mm-by-1mm-by-3mm (lat, vrt, lng) for the planning CT vs. 0.4mm-by-0.4mm for CBCT projections. Overlaying of the contours onto the DTS image allows for visualization of structures of interest. Conclusion: The ability to generate DTS images over a limited range of projection angles allows for reduction in the amount of respiratory motion within each acquisition. DTS may provide improved visualization of structures and lesions as compared to CBCT for highly mobile tumors.

  5. STOCHASTIC DESCRIPTION OF THE HIGH-FREQUENCY CONTENT OF DAILY SUNSPOTS AND EVIDENCE FOR REGIME CHANGES

    SciTech Connect (OSTI)

    Shapoval, A.; Le Mouël, J.-L.; Courtillot, V.; Shnirman, M.

    2015-01-20

    The irregularity index λ is applied to the high-frequency content of daily sunspot numbers ISSN. This λ is a modification of the standard maximal Lyapunov exponent. It is computed here as a function of embedding dimension m, within four-year time windows centered at the maxima of Schwabe cycles. The λ(m) curves form separate clusters (pre-1923 and post-1933). This supports a regime transition and narrows its occurrence to cycle 16, preceding the growth of activity leading to the Modern Maximum. The two regimes are reproduced by a simple autoregressive process AR(1), with the mean of Poisson noise undergoing 11 yr modulation. The autocorrelation a of the process (linked to sunspot lifetime) is a ≈ 0.8 for 1850-1923 and ≈0.95 for 1933-2013. The AR(1) model suggests that groups of spots appear with a Poisson rate and disappear at a constant rate. We further applied the irregularity index to the daily sunspot group number series for the northern and southern hemispheres, provided by the Greenwich Royal Observatory (RGO), in order to study a possible desynchronization. Correlations between the north and south λ(m) curves vary quite strongly with time and indeed show desynchronization. This may reflect a slow change in the dimension of an underlying dynamical system. The ISSN and RGO series of group numbers do not imply an identical mechanism, but both uncover a regime change at a similar time. Computation of the irregularity index near the maximum of cycle 24 will help in checking whether yet another regime change is under way.

  6. Cesium Delivery System for Negative Ion Source at IPR

    SciTech Connect (OSTI)

    Bansal, G.; Pandya, K.; Soni, J.; Gahlaut, A.; Parmar, K. G. [Institute for Plasma Research, Bhat, Gandhinagar, Gujarat, 382 428 (India); Bandyopadhyay, M.; Chakraborty, A.; Singh, M. J. [ITER- India, Institute for Plasma Research, A-29, Sector 25, GIDC, Gandhinagar, Gujarat (India)

    2011-09-26

    The technique of surface production of negative ions using cesium, Cs, has been efficiently exploited over the years for producing negative ion beams with increased current densities from negative ion sources used on neutral beam lines. Deposition of Cs on the source walls and the plasma grid lowers the work function and therefore enables a higher yield of H{sup -}, when hydrogen particles (H and/or H{sub x}{sup +}) strike these surfaces.A single driver RF based (100 kW, 1 MHz) negative ion source test bed, ROBIN, is being set up at IPR under a technical collaboration between IPR and IPP, Germany. The optimization of the Cs oven design to be used on this facility as well as multidriver sources is underway. The characterization experiments of such a Cs delivery system with a 1 g Cs inventory have been carried out using surface ionization technique. The experiments have been carried by delivering Cs into a vacuum chamber without plasma. The linear motion of the surface ionization detector, SID, attached with a linear motion feedthrough allows measuring the angular distribution of the Cs coming out of the oven. Based on the experimental results, a Cs oven for ROBIN has been proposed. The Cs oven design and experimental results of the prototype Cs oven are reported and discussed in the paper.

  7. Negative hydrogen ion production in a helicon plasma source

    SciTech Connect (OSTI)

    Santoso, J. Corr, C. S.; Manoharan, R.; O'Byrne, S.

    2015-09-15

    In order to develop very high energy (>1 MeV) neutral beam injection systems for applications, such as plasma heating in fusion devices, it is necessary first to develop high throughput negative ion sources. For the ITER reference source, this will be realised using caesiated inductively coupled plasma devices, containing either hydrogen or deuterium discharges, operated with high rf input powers (up to 90 kW per driver). It has been suggested that due to their high power coupling efficiency, helicon devices may be able to reduce power requirements and potentially obviate the need for caesiation due to the high plasma densities achievable. Here, we present measurements of negative ion densities in a hydrogen discharge produced by a helicon device, with externally applied DC magnetic fields ranging from 0 to 8.5 mT at 5 and 10 mTorr fill pressures. These measurements were taken in the magnetised plasma interaction experiment at the Australian National University and were performed using the probe-based laser photodetachment technique, modified for the use in the afterglow of the plasma discharge. A peak in the electron density is observed at ∼3 mT and is correlated with changes in the rf power transfer efficiency. With increasing magnetic field, an increase in the negative ion fraction from 0.04 to 0.10 and negative ion densities from 8 × 10{sup 14 }m{sup −3} to 7 × 10{sup 15 }m{sup −3} is observed. It is also shown that the negative ion densities can be increased by a factor of 8 with the application of an external DC magnetic field.

  8. Experimental analysis of thermal performance of flat plate and evacuated tube solar collectors in stationary standard and daily conditions

    SciTech Connect (OSTI)

    Zambolin, E.; Del Col, D.

    2010-08-15

    New comparative tests on two different types of solar collectors are presented in this paper. A standard glazed flat plate collector and an evacuated tube collector are installed in parallel and tested at the same working conditions; the evacuated collector is a direct flow through type with external compound parabolic concentrator (CPC) reflectors. Efficiency in steady-state and quasi-dynamic conditions is measured following the standard and it is compared with the input/output curves measured for the whole day. The first purpose of the present work is the comparison of results in steady-state and quasi-dynamic test methods both for flat plate and evacuated tube collectors. Besides this, the objective is to characterize and to compare the daily energy performance of these two types of collectors. An effective mean for describing and analyzing the daily performance is the so called input/output diagram, in which the collected solar energy is plotted against the daily incident solar radiation. Test runs have been performed in several conditions to reproduce different conventional uses (hot water, space heating, solar cooling). Results are also presented in terms of daily efficiency versus daily average reduced temperature difference: this allows to represent the comparative characteristics of the two collectors when operating under variable conditions, especially with wide range of incidence angles. (author)

  9. Assessing Energy Impact of Plug-In Hybrid Electric Vehicles: Significance of Daily Distance Variation over Time and Among Drivers

    SciTech Connect (OSTI)

    Lin, Zhenhong [ORNL; Greene, David L [ORNL

    2012-01-01

    Accurate assessment of the impact of plug-in hybrid electric vehicles (PHEVs) on petroleum and electricity consumption is a necessary step toward effective policies. Variations in daily vehicle miles traveled (VMT) over time and among drivers affect PHEV energy impact, but the significance is not well understood. This paper uses a graphical illustration, a mathematical derivation, and an empirical study to examine the cause and significance of such an effect. The first two methods reveal that ignoring daily variation in VMT always causes underestimation of petroleum consumption and overestimation of electricity consumption by PHEVs; both biases increase as the assumed PHEV charge-depleting (CD) range moves closer to the average daily VMT. The empirical analysis based on national travel survey data shows that the assumption of uniform daily VMT over time and among drivers causes nearly 68% underestimation of expected petroleum use and nearly 48% overestimation of expected electricity use by PHEVs with a 40-mi CD range (PHEV40s). Also for PHEV40s, consideration of daily variation in VMT over time but not among drivers similar to the way the utility factor curve is derived in SAE Standard SAE J2841 causes underestimation of expected petroleum use by more than 24% and overestimation of expected electricity use by about 17%. Underestimation of petroleum use and overestimation of electricity use increase with larger-battery PHEVs.

  10. Reducing Open Cell Landfill Methane Emissions with a Bioactive Alternative Daily

    SciTech Connect (OSTI)

    Helene Hilger; James Oliver; Jean Bogner; David Jones

    2009-03-31

    Methane and carbon dioxide are formed in landfills as wastes degrade. Molecule-for-molecule, methane is about 20 times more potent than carbon dioxide at trapping heat in the earth's atmosphere, and thus, it is the methane emissions from landfills that are scrutinized. For example, if emissions composed of 60% methane and 40% carbon dioxide were changed to a mix that was 40% methane and 60% carbon dioxide, a 30% reduction in the landfill's global warming potential would result. A 10% methane, 90% carbon dioxide ratio will result in a 75% reduction in global warming potential compared to the baseline. Gas collection from a closed landfill can reduce emissions, and it is sometimes combined with a biocover, an engineered system where methane oxidizing bacteria living in a medium such as compost, convert landfill methane to carbon dioxide and water. Although methane oxidizing bacteria merely convert one greenhouse gas (methane) to another (carbon dioxide), this conversion can offer significant reductions in the overall greenhouse gas contribution, or global warming potential, associated with the landfill. What has not been addressed to date is the fact that methane can also escape from a landfill when the active cell is being filled with waste. Federal regulations require that newly deposited solid waste to be covered daily with a 6 in layer of soil or an alternative daily cover (ADC), such as a canvas tarp. The aim of this study was to assess the feasibility of immobilizing methane oxidizing bacteria into a tarp-like matrix that could be used for alternative daily cover at open landfill cells to prevent methane emissions. A unique method of isolating methanotrophs from landfill cover soil was used to create a liquid culture of mixed methanotrophs. A variety of prospective immobilization techniques were used to affix the bacteria in a tarp-like matrix. Both gel encapsulation of methanotrophs and gels with liquid cores containing methanotrophs were readily made but

  11. Online updating of context-aware landmark detectors for prostate localization in daily treatment CT images

    SciTech Connect (OSTI)

    Dai, Xiubin; Gao, Yaozong; Shen, Dinggang

    2015-05-15

    Purpose: In image guided radiation therapy, it is crucial to fast and accurately localize the prostate in the daily treatment images. To this end, the authors propose an online update scheme for landmark-guided prostate segmentation, which can fully exploit valuable patient-specific information contained in the previous treatment images and can achieve improved performance in landmark detection and prostate segmentation. Methods: To localize the prostate in the daily treatment images, the authors first automatically detect six anatomical landmarks on the prostate boundary by adopting a context-aware landmark detection method. Specifically, in this method, a two-layer regression forest is trained as a detector for each target landmark. Once all the newly detected landmarks from new treatment images are reviewed or adjusted (if necessary) by clinicians, they are further included into the training pool as new patient-specific information to update all the two-layer regression forests for the next treatment day. As more and more treatment images of the current patient are acquired, the two-layer regression forests can be continually updated by incorporating the patient-specific information into the training procedure. After all target landmarks are detected, a multiatlas random sample consensus (multiatlas RANSAC) method is used to segment the entire prostate by fusing multiple previously segmented prostates of the current patient after they are aligned to the current treatment image. Subsequently, the segmented prostate of the current treatment image is again reviewed (or even adjusted if needed) by clinicians before including it as a new shape example into the prostate shape dataset for helping localize the entire prostate in the next treatment image. Results: The experimental results on 330 images of 24 patients show the effectiveness of the authors’ proposed online update scheme in improving the accuracies of both landmark detection and prostate segmentation

  12. The sheath structure around a negatively charged rocket payload

    SciTech Connect (OSTI)

    Neubert, T.; Gilchrist, B.E.; Banks, P.M.; Williamson, P.R. ); Mandell, M.J.; Katz, I. ); Sasaki, S.; Oyama, K.I. ); Raitt, W.J.; Meyers, N.B. )

    1990-05-01

    The sheath structure around a rocket payload charged up to 460 V negative relative to the ambient ionospheric plasma is investigated experimentally and by computer simulations. In one of the experimental modes, the voltage between the payloads was increased linearly from 0 to 460 V in 2.5 s. In this case the tethered mother/daughter functioned as a double probe, the negative probe (mother) reaching large negative potentials, while the positive probe (daughter) stayed close to the ambient plasma potential. A floating probe array was mounted on the mother with probes located, 25, 50, 75, and 100 cm from the rocket surface. The internal impedance of the array was smaller than the probe/plasma impedance, which influenced the potential measurements. However, the measurements contain signatures, which the authors interpret as resulting from the outward expansion of the ion sheath with increasing negative mother potential. This conclusion is substantiated by NASCAP/LEO computer simulations of space charge limited flow. At high potentials, the observed ion current flowing to the mother increased more strongly with bias potential than found from the simulations. It is suggested that the enhancement of the current is generated by secondary electrons emitted by the ions bombarding the payload skin. The effects of the motion of the mother (540-580 m/s) and of the ambient magnetic field have been assessed by the code. It was estimated that the ion current to the mother was increased by 20% relative to a stationary payload, while the incorporation of a magnetic field had no practical influence on the simulation results.

  13. Effects of discharge chamber length on the negative ion generation in volume-produced negative hydrogen ion source

    SciTech Connect (OSTI)

    Chung, Kyoung-Jae; Jung, Bong-Ki; An, YoungHwa; Dang, Jeong-Jeung; Hwang, Y. S.

    2014-02-15

    In a volume-produced negative hydrogen ion source, control of electron temperature is essential due to its close correlation with the generation of highly vibrationally excited hydrogen molecules in the heating region as well as the generation of negative hydrogen ions by dissociative attachment in the extraction region. In this study, geometric effects of the cylindrical discharge chamber on negative ion generation via electron temperature changes are investigated in two discharge chambers with different lengths of 7.5 cm and 11 cm. Measurements with a radio-frequency-compensated Langmuir probe show that the electron temperature in the heating region is significantly increased by reducing the length of the discharge chamber due to the reduced effective plasma size. A particle balance model which is modified to consider the effects of discharge chamber configuration on the plasma parameters explains the variation of the electron temperature with the chamber geometry and gas pressure quite well. Accordingly, H{sup −} ion density measurement with laser photo-detachment in the short chamber shows a few times increase compared to the longer one at the same heating power depending on gas pressure. However, the increase drops significantly as operating gas pressure decreases, indicating increased electron temperatures in the extraction region degrade dissociative attachment significantly especially in the low pressure regime. It is concluded that the increase of electron temperature by adjusting the discharge chamber geometry is efficient to increase H{sup −} ion production as long as low electron temperatures are maintained in the extraction region in volume-produced negative hydrogen ion sources.

  14. Studies of transition states and radicals by negative ion photodetachment

    SciTech Connect (OSTI)

    Metz, R.B.

    1991-12-01

    Negative ion photodetachment is a versatile tool for the production and study of transient neutral species such as reaction intermediates and free radicals. Photodetachment of the stable XHY{sup {minus}} anion provides a direct spectroscopic probe of the transition state region of the potential energy surface for the neutral hydrogen transfer reaction X + HY {yields} XH + Y, where X and Y are halogen atoms. The technique is especially sensitive to resonances, which occur at a specific energy, but the spectra also show features due to direct scattering. We have used collinear adiabatic simulations of the photoelectron spectra to evaluate trail potential energy surfaces for the biomolecular reactions and have extended the adiabatic approach to three dimensions and used it to evaluate empirical potential energy surfaces for the I + Hl and Br + HI reactions. In addition, we have derived an empirical, collinear potential energy surface for the Br + HBr reaction that reproduces our experimental results and have extended this surface to three dimensions. Photodetachment of a negative ion can be also used to study neutral free radicals. We have studied the vibrational and electronic spectroscopy of CH{sub 2}NO{sub 2} by photoelectron spectroscopy of CH{sub 2}NO{sub 2}{sup {minus}}, determining the electron affinity of CH{sub 2}NO{sub 2}, gaining insight on the bonding of the {sup 2}B{sub 1} ground state and observing the {sup 2}A{sub 2} excited state for the first time. Negative ion photodetachment also provides a novel and versatile source of mass-selected, jet-cooled free radicals. We have studied the photodissociation of CH{sub 2}NO{sub 2} at 270, 235, and 208 nm, obtaining information on the dissociation products by measuring the kinetic energy release in the photodissociation.

  15. Lithium aluminum/iron sulfide battery having lithium aluminum and silicon as negative electrode

    DOE Patents [OSTI]

    Gilbert, M.; Kaun, T.

    1984-01-20

    A method of making a negative electrode, the electrode made thereby and a secondary electrochemical c

  16. Electron energy recovery system for negative ion sources

    DOE Patents [OSTI]

    Dagenhart, William K.; Stirling, William L.

    1982-01-01

    An electron energy recovery system for negative ion sources is provided. The system, employs crossed electric and magnetic fields to separate the electrons from ions as they are extracted from a negative ion source plasma generator and before the ions are accelerated to their full kinetic energy. With the electric and magnetic fields oriented 90.degree. to each other, the electrons are separated from the plasma and remain at approximately the electrical potential of the generator in which they were generated. The electrons migrate from the ion beam path in a precessing motion out of the ion accelerating field region into an electron recovery region provided by a specially designed electron collector electrode. The electron collector electrode is uniformly spaced from a surface of the ion generator which is transverse to the direction of migration of the electrons and the two surfaces are contoured in a matching relationship which departs from a planar configuration to provide an electric field component in the recovery region which is parallel to the magnetic field thereby forcing the electrons to be directed into and collected by the electron collector electrode. The collector electrode is maintained at a potential slightly positive with respect to the ion generator so that the electrons are collected at a small fraction of the full accelerating supply voltage energy.

  17. It`s material strength, not a negative Grueneisen gamma

    SciTech Connect (OSTI)

    Sinz, K.H.P.H.; Moss, W.C.

    1993-02-01

    Hydrocode simulations of CORRTEX data (shock position as a function of time) require a model for the material properties of the medium in which the explosion occurs. Prior to the BULLION underground nuclear test, Furnish performed gun experiments on core samples that were taken from a satellite hole near the working point. The authors have analyzed some of these data and constructed a constitutive model that is consistent with the gun data. The model consists of a Mie-Grueneisen equation of state that is parameterized using the Hugoniot, a Grueneisen gamma that is only volume dependent, and a pressure dependent strength model. Previous analyses of these particular experiments have ignored material strength, because of its lack of influence on numerical simulations of the CORRTEX data. However, if strength is excluded, negative gammas are required to fit Furnish`s data, but these negative gammas give an extremely poor fit to the CORRTEX field data. The simple model, which includes strength, has a positive volume dependent gamma. The model fits Furnish`s laboratory data and the measured experimental CORRTEX data. What is remarkable about the model is that all of the parameters in it can be obtained from the gun data, indicating that laboratory experiments of this type (and perhaps others) on core samples are potentially more useful than believed previously.

  18. Bimolecular reaction dynamics from photoelectron spectroscopy of negative ions

    SciTech Connect (OSTI)

    Bradforth, S.E.

    1992-11-01

    The transition state region of a neutral bimolecular reaction may be experimentally investigated by photoelectron spectroscopy of an appropriate negative ion. The photoelectron spectrum provides information on the spectroscopy and dynamics of the short lived transition state and may be used to develop model potential energy surfaces that are semi-quantitative in this important region. The principles of bound {yields} bound negative ion photoelectron spectroscopy are illustrated by way of an example: a full analysis of the photoelectron bands of CN{sup {minus}}, NCO{sup {minus}} and NCS{sup {minus}}. Transition state photoelectron spectra are presented for the following systems Br + HI, Cl + HI, F + HI, F + CH{sub 3}0H,F + C{sub 2}H{sub 5}OH,F + OH and F + H{sub 2}. A time dependent framework for the simulation and interpretation of the bound {yields} free transition state photoelectron spectra is subsequently developed and applied to the hydrogen transfer reactions Br + HI, F + OH {yields} O({sup 3}P, {sup 1}D) + HF and F + H{sub 2}. The theoretical approach for the simulations is a fully quantum-mechanical wave packet propagation on a collinear model reaction potential surface. The connection between the wavepacket time evolution and the photoelectron spectrum is given by the time autocorrelation function. For the benchmark F + H{sub 2} system, comparisons with three-dimensional quantum calculations are made.

  19. Phonon anharmonicity and negative thermal expansion in SnSe

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Bansal, Dipanshu; Hong, Jiawang; Li, Chen W.; May, Andrew F.; Porter, Wallace; Hu, Michael Y.; Abernathy, Douglas L.; Delaire, Olivier

    2016-08-09

    In this paper, the anharmonic phonon properties of SnSe in the Pnma phase were investigated with a combination of experiments and first-principles simulations. Using inelastic neutron scattering (INS) and nuclear resonant inelastic X-ray scattering (NRIXS), we have measured the phonon dispersions and density of states (DOS) and their temperature dependence, which revealed a strong, inhomogeneous shift and broadening of the spectrum on warming. First-principles simulations were performed to rationalize these measurements, and to explain the previously reported anisotropic thermal expansion, in particular the negative thermal expansion within the Sn-Se bilayers. Including the anisotropic strain dependence of the phonon free energy,more » in addition to the electronic ground state energy, is essential to reproduce the negative thermal expansion. From the phonon DOS obtained with INS and additional calorimetry measurements, we quantify the harmonic, dilational, and anharmonic components of the phonon entropy, heat capacity, and free energy. Finally, the origin of the anharmonic phonon thermodynamics is linked to the electronic structure.« less

  20. Alignment Focus of Daily Image Guidance for Concurrent Treatment of Prostate and Pelvic Lymph Nodes

    SciTech Connect (OSTI)

    Ferjani, Samah; Huang, Guangshun; Shang, Qingyang; Stephans, Kevin L.; Zhong, Yahua; Qi, Peng; Tendulkar, Rahul D.; Xia, Ping, E-mail: xiap@ccf.org

    2013-10-01

    Purpose: To determine the dosimetric impact of daily imaging alignment focus on the prostate soft tissue versus the pelvic bones for the concurrent treatment of the prostate and pelvic lymph nodes (PLN) and to assess whether multileaf collimator (MLC) tracking or adaptive planning (ART) is necessary with the current clinical planning margins of 8 mm/6 mm posterior to the prostate and 5 mm to the PLN. Methods and Materials: A total of 124 kilovoltage cone-beam computed tomography (kV-CBCT) images from 6 patients were studied. For each KV-CBCT, 4 plans were retrospectively created using an isocenter shifting method with 2 different alignment focuses (prostate, PLN), an MLC shifting method, and the ART method. The selected dosimetric endpoints were compared among these plans. Results: For the isoshift contour, isoshift bone, MLC shift, and ART plans, D99 of the prostate was ?97% of the prescription dose in 97.6%, 73.4%, 98.4%, and 96.8% of 124 fractions, respectively. Accordingly, D99 of the PLN was ?97% of the prescription dose in 98.4%, 98.4%, 98.4%, and 100% of 124 fractions, respectively. For the rectum, D5 exceeded 105% of the planned D5 (and D5 of ART plans) in 11% (4%), 10% (2%), and 13% (5%) of 124 fractions, respectively. For the bladder, D5 exceeded 105% of the planned D5 (and D5 of ART) plans in 0% (2%), 0% (2%), and 0% (1%) of 124 fractions, respectively. Conclusion: For concurrent treatment of the prostate and PLN, with a planning margin to the prostate of 8 mm/6 mm posterior and a planning margin of 5 mm to the PLN, aligning to the prostate soft tissue can achieve adequate dose coverage to the both target volumes; aligning to the pelvic bone would result in underdosing to the prostate in one-third of fractions. With these planning margins, MLC tracking and ART methods have no dosimetric advantages.

  1. A Bivariate Mixed Distribution with a Heavy-tailed Component and its Application to Single-site Daily Rainfall Simulation

    SciTech Connect (OSTI)

    Li, Chao .; Singh, Vijay P.; Mishra, Ashok K.

    2013-02-06

    This paper presents an improved brivariate mixed distribution, which is capable of modeling the dependence of daily rainfall from two distinct sources (e.g., rainfall from two stations, two consecutive days, or two instruments such as satellite and rain gauge). The distribution couples an existing framework for building a bivariate mixed distribution, the theory of copulae and a hybrid marginal distribution. Contributions of the improved distribution are twofold. One is the appropriate selection of the bivariate dependence structure from a wider admissible choice (10 candidate copula families). The other is the introduction of a marginal distribution capable of better representing low to moderate values as well as extremes of daily rainfall. Among several applications of the improved distribution, particularly presented here is its utility for single-site daily rainfall simulation. Rather than simulating rainfall occurrences and amounts separately, the developed generator unifies the two processes by generalizing daily rainfall as a Markov process with autocorrelation described by the improved bivariate mixed distribution. The generator is first tested on a sample station in Texas. Results reveal that the simulated and observed sequences are in good agreement with respect to essential characteristics. Then, extensive simulation experiments are carried out to compare the developed generator with three other alternative models: the conventional two-state Markov chain generator, the transition probability matrix model and the semi-parametric Markov chain model with kernel density estimation for rainfall amounts. Analyses establish that overall the developed generator is capable of reproducing characteristics of historical extreme rainfall events and is apt at extrapolating rare values beyond the upper range of available observed data. Moreover, it automatically captures the persistence of rainfall amounts on consecutive wet days in a relatively natural and easy way

  2. Trapping and aerogelation of nanoparticles in negative gravity hydrocarbon flames

    SciTech Connect (OSTI)

    Chakrabarty, Rajan K.; Novosselov, Igor V.; Beres, Nicholas D.; Moosmller, Hans; Sorensen, Christopher M.; Stipe, Christopher B.

    2014-06-16

    We report the experimental realization of continuous carbon aerogel production using a flame aerosol reactor by operating it in negative gravity (?g; up-side-down configuration). Buoyancy opposes the fuel and air flow forces in ?g, which eliminates convectional outflow of nanoparticles from the flame and traps them in a distinctive non-tipping, flicker-free, cylindrical flame body, where they grow to millimeter-size aerogel particles and gravitationally fall out. Computational fluid dynamics simulations show that a closed-loop recirculation zone is set up in ?g flames, which reduces the time to gel for nanoparticles by ?10{sup 6}?s, compared to positive gravity (upward rising) flames. Our results open up new possibilities of one-step gas-phase synthesis of a wide variety of aerogels on an industrial scale.

  3. Models of radiofrequency coupling for negative ion sources

    SciTech Connect (OSTI)

    Cavenago, M.; Petrenko, S.

    2012-02-15

    Radiofrequency heating for ICP (inductively coupled plasma) ion sources depends on the source operating pressure, the presence or absence of a Faraday shield, the driver coil geometry, the frequency used, and the magnetic field configuration: in negative ion source a magnetic filter seems necessary for H{sup -} survival. The result of single particle simulations showing the possibility of electron acceleration in the preglow regime and for reasonable driver chamber radius (15 cm) is reported, also as a function of the static external magnetic field. An effective plasma conductivity, depending not only from electron density, temperature, and rf field but also on static magnetic field is here presented and compared to previous models. Use of this conductivity and of multiphysics tools for a plasma transport and heating model is shown and discussed for a small source.

  4. Multiple delivery cesium oven system for negative ion sources

    SciTech Connect (OSTI)

    Bansal, G.; Bhartiya, S.; Pandya, K.; Bandyopadhyay, M.; Singh, M. J.; Soni, J.; Gahlaut, A.; Parmar, K. G.; Chakraborty, A. [Institute for Plasma Research, Bhat, Gandhinagar, Gujarat 382428 (India)

    2012-02-15

    Distribution of cesium in large negative ion beam sources to be operational in ITER, is presently based on the use of three or more cesium ovens, which operate simultaneously and are controlled remotely. However, use of multiple Cs ovens simultaneously is likely to pose difficulties in operation and maintenance of the ovens. An alternate method of Cs delivery, based on a single oven distribution system is proposed as one which could reduce the need of simultaneous operation of many ovens. A proof of principle experiment verifying the concept of a multinozzle distributor based Cs oven has been carried out at Institute for Plasma Research. It is also observed that the Cs flux is not controlled by Cs reservoir temperature after few hours of operation but by the temperature of the distributor which starts behaving as a Cs reservoir.

  5. RF-Plasma Source Commissioning in Indian Negative Ion Facility

    SciTech Connect (OSTI)

    Singh, M. J.; Bandyopadhyay, M.; Yadava, Ratnakar; Chakraborty, A. K.; Bansal, G.; Gahlaut, A.; Soni, J.; Kumar, Sunil; Pandya, K.; Parmar, K. G.; Sonara, J.; Kraus, W.; Heinemann, B.; Riedl, R.; Obermayer, S.; Martens, C.; Franzen, P.; Fantz, U.

    2011-09-26

    The Indian program of the RF based negative ion source has started off with the commissioning of ROBIN, the inductively coupled RF based negative ion source facility under establishment at Institute for Plasma research (IPR), India. The facility is being developed under a technology transfer agreement with IPP Garching. It consists of a single RF driver based beam source (BATMAN replica) coupled to a 100 kW, 1 MHz RF generator with a self excited oscillator, through a matching network, for plasma production and ion extraction and acceleration. The delivery of the RF generator and the RF plasma source without the accelerator, has enabled initiation of plasma production experiments. The recent experimental campaign has established the matching circuit parameters that result in plasma production with density in the range of 0.5-1x10{sup 18}/m{sup 3}, at operational gas pressures ranging between 0.4-1 Pa. Various configurations of the matching network have been experimented upon to obtain a stable operation of the set up for RF powers ranging between 25-85 kW and pulse lengths ranging between 4-20 s. It has been observed that the range of the parameters of the matching circuit, over which the frequency of the power supply is stable, is narrow and further experiments with increased number of turns in the coil are in the pipeline to see if the range can be widened. In this paper, the description of the experimental system and the commissioning data related to the optimisation of the various parameters of the matching network, to obtain stable plasma of required density, are presented and discussed.

  6. Pool daily fuel scheduling. Volume 3: Program listings. Final report, February 1981. [START; MASTER; THCC; HYDR; PSTO; NFLA; LMTF

    SciTech Connect (OSTI)

    Pang, C.K.; Mikolinnas, T.A.

    1981-02-01

    The results and efforts of research and development of methods for daily fuel scheduling performed under EPRI Project RP 1048-5 by Power Technologies, Inc. (PTI) are reported in three volumes: Technical Manual; Programming Manual and Program Listing. Daily fuel scheduling involves the scheduling and dispatching of generating facilities to meet all system loads and operating requirements for periods ranging from a day to a week. Daily fuel scheduling and computer requirements are defined. The scheduling problem is formulated as a mixed-integer linear programming (MILP) optimization problem in which the total system operating cost is minimized. A potentially practical scheduling procedure, based on a combination of search and MILP approaches, was proposed; these two approaches were investigated, coded in FORTRAN and tested individually. Tests using the New York Power Pool system show that the search approach may produce potential savings for fuel scheduling approaches. Additional efforts are needed to make the MILP approach practical. Finally, a number of special scheduling problems have been identified and recommended for future work. This volume of the report (Volume 3) gives the FORTRAN listings of the programs, which had been developed during the course of this project. In the programs, there may be certain statements and functions which could be specific to the PRIME computer system. Comments on them are provided.

  7. Robust activation method for negative electron affinity photocathodes

    SciTech Connect (OSTI)

    Mulhollan, Gregory A.; Bierman, John C.

    2011-09-13

    A method by which photocathodes(201), single crystal, amorphous, or otherwise ordered, can be surface modified to a robust state of lowered and in best cases negative, electron affinity has been discovered. Conventional methods employ the use of Cs(203) and an oxidizing agent(207), typically carried by diatomic oxygen or by more complex molecules, for example nitrogen trifluoride, to achieve a lowered electron affinity(404). In the improved activation method, a second alkali, other than Cs(205), is introduced onto the surface during the activation process, either by co-deposition, yo-yo, or sporadic or intermittent application. Best effect for GaAs photocathodes has been found through the use of Li(402) as the second alkali, though nearly the same effect can be found by employing Na(406). Suitable photocathodes are those which are grown, cut from boules, implanted, rolled, deposited or otherwise fabricated in a fashion and shape desired for test or manufacture independently supported or atop a support structure or within a framework or otherwise affixed or suspended in the place and position required for use.

  8. Negative terahertz conductivity in disordered graphene bilayers with population inversion

    SciTech Connect (OSTI)

    Svintsov, D.; Otsuji, T.; Ryzhii, V.; Mitin, V.; Shur, M. S.

    2015-03-16

    The gapless energy band spectra make the structures based on graphene and graphene bilayer with the population inversion to be promising media for the interband terahertz (THz) lasing. However, a strong intraband absorption at THz frequencies still poses a challenge for efficient THz lasing. In this paper, we show that in the pumped graphene bilayer, the indirect interband radiative transitions accompanied by scattering of carriers by disorder can provide a substantial negative contribution to the THz conductivity (together with the direct interband transitions). In the graphene bilayer on high-? substrates with point charged defects, these transitions substantially compensate the losses due to the intraband (Drude) absorption. We also demonstrate that the indirect interband contribution to the THz conductivity in a graphene bilayer with the extended defects (such as the charged impurity clusters) can surpass by several times the fundamental limit associated with the direct interband transitions, and the Drude conductivity as well. These predictions can affect the strategy of the graphene-based THz laser implementation.

  9. Observation of two distinct negative trions in tungsten disulfide monolayers

    SciTech Connect (OSTI)

    Boulesbaa, Abdelaziz; Huang, Bing; Wang, Kai; Lin, Ming-Wei; Mahjouri-Samani, Masoud; Rouleau, Christopher M.; Xiao, Kai; Yoon, Mina; Sumpter, Bobby G.; Puretzky, Alexander A.; Geohegan, David B.

    2015-09-25

    We report on the observation of two distinct photogenerated negative trion states TA and TB in two-dimensional tungsten disulfide (2D-WS2) monolayers. These trions are postulated to emerge from their parent excitons XA and XB, which originate from spin-orbit-split (SOS) levels in the conduction band (CB) and valence band (VB). Time-resolved spectroscopy measurements suggests that Pauli blocking controls a competition process between TA and TB photoformation, following dissociation of XA and XB through hole trapping at internal or substrate defect sites. While TA arises directly from its parent XA, TB emerges through a different transition accessible only after XB dissociates through a hole trapping channel. This discovery of additional optically-active band-edge transitions in atomically-thin metal dichalcogenides may revolutionize optoelectronic applications and fundamental research opportunities for many-body interaction physics. Ultrafast pump-probe spectroscopy of two-dimensional tungsten disulfide monolayers (2D-WS2) grown on sapphire substrates revealed two transient absorption spectral peaks that are attributed to distinct negative trions at ~2.02 eV (T1) and ~1.98 eV (T2). The dynamics measurements indicate that trion formation by the probe is enabled by photodoped electrons that remain after trapping of holes from excitons or free electron-hole pairs at defect sites in the crystal or on the substrate. Dynamics of the excitons XA and XB’s characteristic absorption bands, at ~2.03 and ~2.40 eV, respectively, were separately monitored and compared with the photoinduced absorption features. Selective excitation of the lowest exciton level XA using λpump < 2.4 eV forms only trion T1, which implies that the electron that remains

  10. Observation of two distinct negative trions in tungsten disulfide monolayers

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Boulesbaa, Abdelaziz; Huang, Bing; Wang, Kai; Lin, Ming-Wei; Mahjouri-Samani, Masoud; Rouleau, Christopher M.; Xiao, Kai; Yoon, Mina; Sumpter, Bobby G.; Puretzky, Alexander A.; et al

    2015-09-25

    We report on the observation of two distinct photogenerated negative trion states TA and TB in two-dimensional tungsten disulfide (2D-WS2) monolayers. These trions are postulated to emerge from their parent excitons XA and XB, which originate from spin-orbit-split (SOS) levels in the conduction band (CB) and valence band (VB). Time-resolved spectroscopy measurements suggests that Pauli blocking controls a competition process between TA and TB photoformation, following dissociation of XA and XB through hole trapping at internal or substrate defect sites. While TA arises directly from its parent XA, TB emerges through a different transition accessible only after XB dissociates throughmore » a hole trapping channel. This discovery of additional optically-active band-edge transitions in atomically-thin metal dichalcogenides may revolutionize optoelectronic applications and fundamental research opportunities for many-body interaction physics. Ultrafast pump-probe spectroscopy of two-dimensional tungsten disulfide monolayers (2D-WS2) grown on sapphire substrates revealed two transient absorption spectral peaks that are attributed to distinct negative trions at ~2.02 eV (T1) and ~1.98 eV (T2). The dynamics measurements indicate that trion formation by the probe is enabled by photodoped electrons that remain after trapping of holes from excitons or free electron-hole pairs at defect sites in the crystal or on the substrate. Dynamics of the excitons XA and XB’s characteristic absorption bands, at ~2.03 and ~2.40 eV, respectively, were separately monitored and compared with the photoinduced absorption features. Selective excitation of the lowest exciton level XA using λpump < 2.4 eV forms only trion T1, which implies that the electron that remains from the dissociation of exciton XA is involved in the creation of this trion with a binding energy ~ 10 meV with respect to XA. The absorption peak that corresponds to trion T2 appears when λpump > 2.4 eV, which is just

  11. Radiative lifetimes of metastable states of negative ions

    SciTech Connect (OSTI)

    Andersson, Pontus; Fritioff, Karin; Sandstroem, Joakim; Collins, Gerard; Hanstorp, Dag; Ellmann, Anna; Schef, Peter; Lundin, Peter; Mannervik, Sven; Royen, Peder; Froese Fischer, K. Charlotte; Oesterdahl, Fabian; Rostohar, Danijela; Pegg, David J.; Gibson, N. D.; Danared, Haakan; Kaellberg, Anders

    2006-03-15

    We present a technique for measuring the radiative lifetimes of metastable states of negative ions that involves the use of a heavy-ion storage ring. The method has been applied to investigate the radiative decay of the np{sup 3} {sup 2}P{sub 1/2} levels of Te{sup -}(n=5) and Se{sup -}(n=4) and the 3p{sup 3} {sup 2}D state of Si{sup -} for which the J=3/2 and 5/2 levels were unresolved. All of these states are metastable and decay primarily by emission of E2 and M1 radiation. Multi Configuration Dirac-Hartree-Fock calculations of rates for the transitions in Te{sup -} and Se{sup -} yielded lifetimes of 0.45 s and 4.7 s, respectively. The measured values agree well with these predicted values. In the case of the {sup 2}D state of Si{sup -}, however, our measurement was only able to set a lower limit on the lifetime. The upper limit of the lifetime that can be measured with our apparatus is set by how long the ions can be stored in the ring, a limit determined by the rate of collisional detachment. Our lower limit of 1 min for the lifetime of the {sup 2}D state is consistent with both the calculated lifetimes of 162 s for the {sup 2}D{sub 3/2} level and 27.3 h for the {sup 2}D{sub 5/2} level reported by O'Malley and Beck and 14.5 h and 12.5 h, respectively, from our Breit-Pauli calculations.

  12. Negative Valve Overlap Reforming Chemistry in Low-Oxygen Environments

    SciTech Connect (OSTI)

    Szybist, James P; Steeper, Richard R.; Splitter, Derek A; Kalaskar, Vickey B; Pihl, Josh A; Daw, C Stuart

    2014-01-01

    Fuel injection into the negative valve overlap (NVO) period is a common method for controlling combustion phasing in homogeneous charge compression ignition (HCCI) and other forms of advanced combustion. When fuel is injected into O2-deficient NVO conditions, a portion of the fuel can be converted to products containing significant levels of H2 and CO. Additionally, other short chain hydrocarbons are produced by means of thermal cracking, water-gas shift, and partial oxidation reactions. The present study experimentally investigates the fuel reforming chemistry that occurs during NVO. To this end, two very different experimental facilities are utilized and their results are compared. One facility is located at Oak Ridge National Laboratory, which uses a custom research engine cycle developed to isolate the NVO event from main combustion, allowing a steady stream of NVO reformate to be exhausted from the engine and chemically analyzed. The other experimental facility, located at Sandia National Laboratories, uses a dump valve to capture the exhaust from a single NVO event for analysis. Results from the two experiments are in excellent trend-wise agreement and indicate that the reforming process under low-O2 conditions produces substantial concentrations of H2, CO, methane, and other short-chain hydrocarbon species. The concentration of these species is found to be strongly dependent on fuel injection timing and injected fuel type, with weaker dependencies on NVO duration and initial temperature, indicating that NVO reforming is kinetically slow. Further, NVO reforming does not require a large energy input from the engine, meaning that it is not thermodynamically expensive. The implications of these results on HCCI and other forms of combustion are discussed in detail.

  13. Study of the negative ion extraction mechanism from a double-ion plasma in negative ion sources

    SciTech Connect (OSTI)

    Goto, I.; Nishioka, S.; Hatayama, A.; Miyamoto, K.

    2015-04-08

    We have developed a 2D3V-PIC model of the extraction region, aiming to clarify the basic extraction mechanism of H{sup −} ions from the double-ion plasma in H{sup −} negative ion sources. The result shows the same tendency of the H{sup −} ion density n{sub H{sup −}} as that observed in the experiments, i.e.,n{sub H{sup −}} in the upstream region away from the plasma meniscus (H{sup −} emitting surface) has been reduced by applying the extraction voltage. At the same time, relatively slow temporal oscillation of the electric potential compared with the electron plasma frequency has been observed in the extraction region. Results of the systematic study using a 1D3V-PIC model with the uniform magnetic field confirm the result that the electrostatic oscillation is identified to be lower hybrid wave. The effect of this oscillation on the H{sup −} transport will be studied in the future.

  14. Acceleration of 500 keV Negative Ion Beams By Tuning Vacuum Insulation Distance On JT-60 Negative Ion Source

    SciTech Connect (OSTI)

    Kojima, A.; Hanada, M.; Tanaka, Y.; Taniguchi, M.; Kashiwagi, M.; Inoue, T.; Umeda, N.; Watanabe, K.; Tobari, H.; Kobayashi, S.; Yamano, Y.; Grisham, L. R.

    2011-09-26

    Acceleration of a 500 keV beam up to 2.8 A has been achieved on a JT-60U negative ion source with a three-stage accelerator by overcoming low voltage holding which is one of the critical issues for realization of the JT-60SA ion source. In order to improve the voltage holding, preliminary voltage holding tests with small-size grids with uniform and locally intense electric fields were carried out, and suggested that the voltage holding was degraded by both the size and local electric field effects. Therefore, the local electric field was reduced by tuning gap lengths between the large size grids and grid support structures of the accelerator. Moreover, a beam radiation shield which limited extension of the minimum gap length was also optimized so as to reduce the local electric field while maintaining the shielding effect. These modifications were based on the experiment results, and significantly increased the voltage holding from <150 kV/stage for the original configuration to 200 kV/stage. These techniques for improvement of voltage holding should also be applicable to other large ion sources accelerators such as those for ITER.

  15. Size scaling of negative hydrogen ion sources for fusion

    SciTech Connect (OSTI)

    Fantz, U. Franzen, P.; Kraus, W.; Schiesko, L.; Wimmer, C.; Wünderlich, D.

    2015-04-08

    The RF-driven negative hydrogen ion source (H{sup −}, D{sup −}) for the international fusion experiment ITER has a width of 0.9 m and a height of 1.9 m and is based on a ⅛ scale prototype source being in operation at the IPP test facilities BATMAN and MANITU for many years. Among the challenges to meet the required parameters in a caesiated source at a source pressure of 0.3 Pa or less is the challenge in size scaling of a factor of eight. As an intermediate step a ½ scale ITER source went into operation at the IPP test facility ELISE with the first plasma in February 2013. The experience and results gained so far at ELISE allowed a size scaling study from the prototype source towards the ITER relevant size at ELISE, in which operational issues, physical aspects and the source performance is addressed, highlighting differences as well as similarities. The most ITER relevant results are: low pressure operation down to 0.2 Pa is possible without problems; the magnetic filter field created by a current in the plasma grid is sufficient to reduce the electron temperature below the target value of 1 eV and to reduce together with the bias applied between the differently shaped bias plate and the plasma grid the amount of co-extracted electrons. An asymmetry of the co-extracted electron currents in the two grid segments is measured, varying strongly with filter field and bias. Contrary to the prototype source, a dedicated plasma drift in vertical direction is not observed. As in the prototype source, the performance in deuterium is limited by the amount of co-extracted electrons in short as well as in long pulse operation. Caesium conditioning is much harder in deuterium than in hydrogen for which fast and reproducible conditioning is achieved. First estimates reveal a caesium consumption comparable to the one in the prototype source despite the large size.

  16. Positive and negative ion beam merging system for neutral beam production

    DOE Patents [OSTI]

    Leung, Ka-Ngo; Reijonen, Jani

    2005-12-13

    The positive and negative ion beam merging system extracts positive and negative ions of the same species and of the same energy from two separate ion sources. The positive and negative ions from both sources pass through a bending magnetic field region between the pole faces of an electromagnet. Since the positive and negative ions come from mirror image positions on opposite sides of a beam axis, and the positive and negative ions are identical, the trajectories will be symmetrical and the positive and negative ion beams will merge into a single neutral beam as they leave the pole face of the electromagnet. The ion sources are preferably multicusp plasma ion sources. The ion sources may include a multi-aperture extraction system for increasing ion current from the sources.

  17. SU-E-T-86: Comparison of Two Commercially Available Programs for the Evaluation of Delivered Daily Dose Using Cone Beam CT (CBCT)

    SciTech Connect (OSTI)

    Tuohy, R; Bosse, C; Mavroidis, P; Shi, Z; Crownover, R; Papanikolaou, N; Stathakis, S

    2014-06-01

    Purpose: In this study, two commercially available programs were compared for the evaluation of delivered daily dose using cone beam CT (CBCT). Methods: Thirty (n=30) patients previously treated in our clinic (10 prostate, 10 SBRT lung and 10 abdomen) were used in this study. The patients' plans were optimized and calculated using the Pinnacle treatment planning system. The daily CBCT scans were imported into Velocity and RayStation along with the corresponding planning CTs, structure sets and 3D dose distributions for each patient. The organs at risk (OAR) were contoured on each CBCT by the prescribing physician and were included in the evaluation of the daily delivered dose. Each CBCT was registered to the planning CT, once with rigid registration and then again, separately, with deformable registration. After registering each CBCT, the dose distribution from the planning CT was overlaid and the dose volume histograms (DVH) for the OAR and the planning target volumes (PTV) were calculated. Results: For prostate patients, we observed daily volume changes for the OARs. The DVH analysis for those patients showed variation in the sparing of the OARs while PTV coverage remained virtually unchanged using both Velocity and RayStation systems. Similar results were observed for abdominal patients. In contrast, for SBRT lung patients, the DVH for the OARs and target were comparable to those from the initial treatment plan. Differences in organ volume and organ doses were also observed when comparing the daily fractions using deformable and rigid registrations. Conclusion: By using daily CBCT dose reconstruction, we proved PTV coverage for prostate and abdominal targets is adequate. However, there is significant dosimetric change for the OARs. For lung SBRT patients, the delivered daily dose for both PTV and OAR is comparable to the planned dose with no significant differences.

  18. Characteristics of ion acoustic solitary waves in a negative ion plasma with superthermal electrons

    SciTech Connect (OSTI)

    Rouhani, M. R.; Ebne Abbasi, Z.

    2012-11-15

    The behavior of ion acoustic solitons in a plasma including positive and negative ions and kappa distributed electrons is studied, using both small amplitude and arbitrary amplitude approaches. The existence regions of compressive and rarefactive solitons will depend on negative to positive ion density ratio ({nu}) and kappa parameter as well as positive to negative ion mass ratio (Q). The numerical analysis of Sagdeev potential shows that for a chosen plasma with fixed Q, the existence regime of compressive solitons is decreased (increased) by increasing density ratio (kappa parameter), while for rarefactive solitons these conditions are quite opposite. Additionally, the possibility of propagation of both compressive and rarefactive subsonic solitons is investigated. It is found that by increasing negative ions, the existence domains of subsonic solitons are decreased, so that in excess of negative ions subsonic solitons will not propagate even at the presence of superthermal electrons. Indeed, there is a critical negative ion density ratio for all values of kappa, above that only supersonic solitons are observed. Furthermore, in addition to the previous results based on Cairns-distributed electrons [R. A. Cairns et al., Geophys. Res. Lett. 22, 2709 (1995)], which predicted that both compressive and rarefactive solitons can coexist simultaneously, we have also found the regions of {nu} and {kappa} in which either positive or negative potentials are permitted (i.e., not together). This research will be helpful in understanding the properties of space and laboratory plasmas containing negative ions with energetic electrons.

  19. NIAMEY DAILY RAINFALL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2006 -2 -1 0 1 +2 +3 Average Normalized Departure () Time series (1941-2006) of normalized April-October rainfall departures () for Niamey (2.1666 o E, 13.4833 o N) in Niger...

  20. ARM - Daily Report Archive

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ... We are back in full operation, just in time for possible ... The new Seasoar steering wing and rudder received its first ... the desiccant indicator is red confirming that the inside ...

  1. Experimental evidence on removing copper and light-induced degradation from silicon by negative charge

    SciTech Connect (OSTI)

    Boulfrad, Yacine Lindroos, Jeanette; Yli-Koski, Marko; Savin, Hele; Wagner, Matthias; Wolny, Franziska

    2014-11-03

    In addition to boron and oxygen, copper is also known to cause light-induced degradation (LID) in silicon. We have demonstrated previously that LID can be prevented by depositing negative corona charge onto the wafer surfaces. Positively charged interstitial copper ions are proposed to diffuse to the negatively charged surface and consequently empty the bulk of copper. In this study, copper out-diffusion was confirmed by chemical analysis of the near surface region of negatively/positively charged silicon wafer. Furthermore, LID was permanently removed by etching the copper-rich surface layer after negative charge deposition. These results demonstrate that (i) copper can be effectively removed from the bulk by negative charge, (ii) under illumination copper forms a recombination active defect in the bulk of the wafer causing severe light induced degradation.

  2. SU-E-T-453: A Novel Daily QA System for Robotic Image Guided Radiosurgery with Variable Aperture Collimator

    SciTech Connect (OSTI)

    Wang, L; Nelson, B

    2014-06-01

    Purpose: A novel end-to-end system using a CCD camera and a scintillator based phantom that is capable of measuring the beam-by-beam delivery accuracy of Robotic Radiosurgery has been developed and reported in our previous work. This work investigates its application to end-to-end type daily QA for Robotic Radiosurgery (Cyberknife) with Variable Aperture Collimator (Iris). Methods: The phantom was first scanned with a CT scanner at 0.625 slice thickness and exported to the Cyberknife Muliplan (v4.6) treatment planning system. An isocentric treatment plan was created consisting of ten beams of 25 Monitor Units each using Iris apertures of 7.5, 10, 15, 20, and 25 mm. The plan was delivered six times in two days on the Cyberknife G4 system with fiducial tracking on the four metal fiducials embedded in phantom with re-positioning between the measurements. The beam vectors (X, Y, Z) are measured and compared with the plan from the machine delivery file (XML file). The Iris apertures (FWHM) were measured from the beam flux map and compared with the commissioning data. Results: The average beam positioning accuracies of the six deliveries are 0.71 0.40 mm, 0.72 0.44 mm, 0.74 0.42 mm, 0.70 0.40 mm, 0.79 0.44 mm and 0.69 0.41 mm respectively. Radiation beam width (FWHM) variations are within 0.05 mm, and they agree with the commissioning data within 0.22 mm. The delivery time for the plan is about 7 minutes and the results are given instantly. Conclusion: The experimental results agree with stated sub-millimeter delivery accuracy of Cyberknife system. Beam FWHM variations comply with the 0.2 mm accuracy of the Iris collimator at SAD. The XRV-100 system has proven to be a powerful tool in performing end-to-end type tests for Robotic Image Guided Radiosurgery Daily QA.

  3. Semi volatile organic compounds in ambient PM2.5. Seasonal trends and daily resolved source contributions

    SciTech Connect (OSTI)

    Juergen Schnelle-Kreis; Martin Sklorz; Juergen Orasche; Matthias Stoelzel; Annette Peters; Ralf Zimmermann

    2007-06-01

    Concentrations of ambient semivolatile organic compounds (SVOC) in the PM2.5 fraction of Augsburg, Germany, have been monitored on a daily basis from January 2003 through December 2004. Samples were taken in a large garden in the city center. Quantitative analysis of n-alkanes, alkanones, alkanoic acid methylesters, long chain linear alkyl benzenes and toluenes, hopanes, polycyclic aromatic hydrocarbons (PAH) and oxidized PAH, and some abietan type diterpenes was done. All compounds showed distinct seasonal variations in concentration. Most compounds showed highest concentrations during the cold seasons, but some n-alkanones and 6,10,14-trimethylpentadecanone showed maximum concentration during summer. Changes in patterns between and within compound classes were obvious, e.g., the hopane pattern exhibited a strong seasonal variation. The main source related contributions to changes observed were discussed. Using positive matrix factorization (PMF) for the statistical investigation of the data set, five factors have been separated. These factors are dominated by the pattern of single sources or groups of similar sources: factor 1, lubricating oil; factor 2, emissions of unburned diesel and heating oil consumption; factor 3, wood combustion; factor 4, brown coal combustion; and factor 5, biogenic emissions and transport components. Like the SVOC, the factors showed strong seasonality with highest values in winter for factors 1-4 and in summer for factor 5. 56 refs., 3 figs., 1 tab.

  4. Relative Accuracy of 1-Minute and Daily Total Solar Radiation Data for 12 Global and 4 Direct Beam Solar Radiometers

    SciTech Connect (OSTI)

    Myers, D.; Wilcox, S. M.

    2009-01-01

    We evaluated the relative performance of 12 global and four direct beam solar radiometers deployed at a single site over a 12-month period. Test radiometer irradiances were compared with a reference irradiance consisting of either an absolute cavity radiometer (during calibrations) or a low uncertainty thermopile pyrheliometer (during the evaluation period) for pyrheliometers; and for pyranometers a reference global irradiance computed from the reference pyrheliometer and diffuse irradiance from a shaded pyranometer. One minute averages of 3-second data for 12 months from the test instrument measurements were compared with the computed reference data set. Combined uncertainty in the computed reference irradiance is 1.8% {+-} 0.5%. Total uncertainty in the pyranometer comparisons is {+-}2.5%. We show mean percent difference between reference global irradiance and test pyranometer 1 minute data as a function of zenith angle, and percent differences between daily totals for the reference and test irradiances as a function of day number. We offer no explicit conclusion about the performance of instrument models, as a general array of applications with a wide range of instrumentation and accuracy requirements could be addressed with any of the radiometers.

  5. Permeability barrier of Gram-negative cell envelopes and approaches to bypass it

    SciTech Connect (OSTI)

    Zgurskaya, Helen I.; López, Cesar A.; Gnanakaran, Sandrasegaram

    2015-09-18

    Gram-negative bacteria are intrinsically resistant to many antibiotics. Species that have acquired multidrug resistance and cause infections that are effectively untreatable present a serious threat to public health. The problem is broadly recognized and tackled at both the fundamental and applied levels. This article summarizes current advances in understanding the molecular bases of the low permeability barrier of Gram-negative pathogens, which is the major obstacle in discovery and development of antibiotics effective against such pathogens. Gaps in knowledge and specific strategies to break this barrier and to achieve potent activities against difficult Gram-negative bacteria are also discussed.

  6. Negative differential resistance in GaN tunneling hot electron transistors

    SciTech Connect (OSTI)

    Yang, Zhichao; Nath, Digbijoy; Rajan, Siddharth

    2014-11-17

    Room temperature negative differential resistance is demonstrated in a unipolar GaN-based tunneling hot electron transistor. Such a device employs tunnel-injected electrons to vary the electron energy and change the fraction of reflected electrons, and shows repeatable negative differential resistance with a peak to valley current ratio of 7.2. The device was stable when biased in the negative resistance regime and tunable by changing collector bias. Good repeatability and double-sweep characteristics at room temperature show the potential of such device for high frequency oscillators based on quasi-ballistic transport.

  7. Intermetallic negative electrodes for non-aqueous lithium cells and batteries

    DOE Patents [OSTI]

    Thackeray, Michael M.; Vaughey, John T.; Johnson, Christopher S.; Fransson, Linda M.; Edstrom, Ester Kristina; Henriksen, Gary

    2004-05-04

    A method of operating an electrochemical cell is disclosed. The cell has an intermetallic negative electrode of Cu.sub.6-x M.sub.x Sn.sub.5, wherein x is .ltoreq.3 and M is one or more metals including Si and a positive electrode containing Li in which Li is shuttled between the positive electrode and the negative electrode during charge and discharge to form a lithiated intermetallic negative electrode during charge. The voltage of the electrochemical cell is controlled during the charge portion of the charge-discharge cycles so that the potential of the lithiated intermetallic negative electrode in the fully charged electrochemical cell is less than 0.2 V but greater than 0 V versus metallic lithium.

  8. Study of negative hydrogen ion beam optics using the 3D3V PIC model

    SciTech Connect (OSTI)

    Miyamoto, K.; Nishioka, S.; Goto, I.; Hatayama, A.; Hanada, M.; Kojima, A.

    2015-04-08

    The mechanism of negative ion extraction under real conditions with the complex magnetic field is studied by using the 3D PIC simulation code. The extraction region of the negative ion source for the negative ion based neutral beam injection system in fusion reactors is modelled. It is shown that the E x B drift of electrons is caused by the magnetic filter and the electron suppression magnetic field, and the resultant asymmetry of the plasma meniscus. Furthermore, it is indicated that that the asymmetry of the plasma meniscus results in the asymmetry of negative ion beam profile including the beam halo. It could be demonstrated theoretically that the E x B drift is not significantly weakened by the elastic collisions of the electrons with neutral particles.

  9. Effect of nickel grid parameters on production of negative hydrogen ions

    SciTech Connect (OSTI)

    Oohara, W.; Yokoyama, H.; Takeda, Toshiaki; Maetani, Y.; Takeda, Takashi; Kawata, K.

    2014-06-15

    Negative hydrogen ions are produced by plasma-assisted catalytic ionization using a nickel grid. When positive ions passing through the grid are decelerated by an electric field, the extraction current density of passing positive ions is sharply reduced by neutralization and negative ionization of the ions. This phenomenon is found to depend on the specific surface area of the grid and the current density.

  10. Research progress on ionic plasmas generated in an intense hydrogen negative ion source

    SciTech Connect (OSTI)

    Takeiri, Y. Tsumori, K.; Nagaoka, K.; Kaneko, O.; Ikeda, K.; Nakano, H.; Kisaki, M.; Tokuzawa, T.; Osakabe, M.; Kondo, T.; Sato, M.; Shibuya, M.; Komada, S.; Sekiguchi, H.; Geng, S.

    2015-04-08

    Characteristics of ionic plasmas, observed in a high-density hydrogen negative ion source, are investigated with a multi-diagnostics system. The ionic plasma, which consists of hydrogen positive- and negative-ions with a significantly low-density of electrons, is generated in the ion extraction region, from which the negative ions are extracted through the plasma grid. The negative ion density, i.e., the ionic plasma density, as high as the order of 110{sup 17}m{sup ?3}, is measured with cavity ring-down spectroscopy, while the electron density is lower than 110{sup 16}m{sup ?3}, which is confirmed with millimeter-wave interferometer. Reduction of the negative ion density is observed at the negative ion extraction, and at that time the electron flow into the ionic plasma region is observed to conserve the charge neutrality. Distribution of the plasma potential is measured in the extraction region in the direction normal to the plasma grid surface with a Langmuir probe, and the results suggest that the sheath is formed at the plasma boundary to the plasma grid to which the bias voltage is applied. The beam extraction should drive the negative ion transport in the ionic plasma across the sheath formed on the extraction surface. Larger reduction of the negative ions at the beam extraction is observed in a region above the extraction aperture on the plasma grid, which is confirmed with 2D image measurement of the H? emission and cavity ring-down spectroscopy. The electron distribution is also measured near the plasma grid surface. These various properties observed in the ionic plasma are discussed.

  11. Daily growth increments in otoliths of juvenile black rockfish, Sebastes melanops: an evaluation of autoradiography as a new method of validation

    SciTech Connect (OSTI)

    Not Available

    1988-10-01

    This study evaluates the commonly used oxytetracycline hydrochloride (OTC) and an alternate chemical, the radioisotope calcium-45, in terms of their success as time-markers to validate daily growth increment formation in the otoliths of juvenile black rockfish, Sebastes melanops.

  12. Time-fractional Gardner equation for ion-acoustic waves in negative-ion-beam plasma with negative ions and nonthermal nonextensive electrons

    SciTech Connect (OSTI)

    Guo, Shimin Mei, Liquan; Zhang, Zhengqiang

    2015-05-15

    Nonlinear propagation of ion-acoustic waves is investigated in a one-dimensional, unmagnetized plasma consisting of positive ions, negative ions, and nonthermal electrons featuring Tsallis distribution that is penetrated by a negative-ion-beam. The classical Gardner equation is derived to describe nonlinear behavior of ion-acoustic waves in the considered plasma system via reductive perturbation technique. We convert the classical Gardner equation into the time-fractional Gardner equation by Agrawal's method, where the time-fractional term is under the sense of Riesz fractional derivative. Employing variational iteration method, we construct solitary wave solutions of the time-fractional Gardner equation with initial condition which depends on the nonlinear and dispersion coefficients. The effect of the plasma parameters on the compressive and rarefactive ion-acoustic solitary waves is also discussed in detail.

  13. Negative running of the spectral index, hemispherical asymmetry and the consistency of Planck with large r

    SciTech Connect (OSTI)

    McDonald, John

    2014-11-01

    Planck favours a negative running of the spectral index, with the likelihood being dominated by low multipoles l?<50 and no preference for running at higher l. A negative spectral index is also necessary for the 2- Planck upper bound on the tensor-to-scalar ratio r to be consistent with values significantly larger than 0.1. Planck has also observed a hemispherical asymmetry of the CMB power spectrum, again mostly at low multipoles. Here we consider whether the physics responsible for the hemispherical asymmetry could also account for the negative running of the spectral index and the consistency of Planck with a large value of r. A negative running of the spectral index can be generated if the hemispherical asymmetry is due to a scale- and space-dependent modulation which suppresses the CMB power spectrum at low multipoles. We show that the observed hemispherical asymmetry at low l can be generated while satisfying constraints on the asymmetry at higher l and generating a negative spectral index of the right magnitude to account for the Planck observation and to allow Planck to be consistent with a large value of r.

  14. Physically consistent simulation of mesoscale chemical kinetics: The non-negative FIS-{alpha} method

    SciTech Connect (OSTI)

    Dana, Saswati, E-mail: saswatid@rishi.serc.iisc.ernet.in [Supercomputer Education and Research Centre, Indian Institute of Science, Bangalore 560012 (India); Raha, Soumyendu, E-mail: raha@serc.iisc.ernet.in [Supercomputer Education and Research Centre, Indian Institute of Science, Bangalore 560012 (India)

    2011-10-01

    Biochemical pathways involving chemical kinetics in medium concentrations (i.e., at mesoscale) of the reacting molecules can be approximated as chemical Langevin equations (CLE) systems. We address the physically consistent non-negative simulation of the CLE sample paths as well as the issue of non-Lipschitz diffusion coefficients when a species approaches depletion and any stiffness due to faster reactions. The non-negative Fully Implicit Stochastic {alpha} (FIS {alpha}) method in which stopped reaction channels due to depleted reactants are deleted until a reactant concentration rises again, for non-negativity preservation and in which a positive definite Jacobian is maintained to deal with possible stiffness, is proposed and analysed. The method is illustrated with the computation of active Protein Kinase C response in the Protein Kinase C pathway.

  15. Laser photodetachment diagnostics of a 1/3-size negative hydrogen ion source for NBI

    SciTech Connect (OSTI)

    Geng, S.; Tsumori, K.; Nakano, H.; Kisaki, M.; Ikeda, K.; Takeiri, Y.; Osakabe, M.; Nagaoka, K.; Kaneko, O.

    2015-04-08

    To investigate the flows of charged particles in front of the plasma grid (PG) in a negative hydrogen ion source, the information of the local densities of electrons and negative hydrogen ions (H-) are necessary. For this purpose, the laser photodetachment is applied for pure hydrogen plasmas and Cs-seeded plasma in a 1/3-size negative hydrogen ion source in NIFS-NBI test stand. The H- density obtained by photodetachment is calibrated by the results from cavity ring-down (CRD). The pressure dependence and PG bias dependence of the local H- density are presented and discussed. The results show that H- density increases significantly by seeding Cs into the plasma. In Cs-seeded plasma, relativity exists between the H- ion density and plasma potential.

  16. Photodissociation and charge transfer dynamics of negative ions studied with femtosecond photoelectron spectroscopy

    SciTech Connect (OSTI)

    Zanni, Martin T.

    1999-12-17

    This dissertation presents studies aimed at understanding the potential energy surfaces and dynamics of isolated negative ions, and the effects of solvent on each. Although negative ions play important roles in atmospheric and solution phase chemistry, to a large extent the ground and excited state potential energy surfaces of gas phase negative ions are poorly characterized, and solvent effects even less well understood. In an effort to fill this gap, the author's coworkers and the author have developed a new technique, anion femtosecond photoelectron spectroscopy, and applied it to gas phase photodissociation and charge transfer processes. Studies are presented that (1) characterize the ground and excited states of isolated and clustered anions, (2) monitor the photodissociation dynamics of isolated and clustered anions, and (3) explore the charge-transfer-to-solvent states of atomic iodide clustered with polar and non-polar solvents.

  17. Roles of a plasma grid in a negative hydrogen ion source

    SciTech Connect (OSTI)

    Bacal, M.; Sasao, M.; Wada, M.; McAdams, R.

    2015-04-08

    The plasma grid is electrically biased with respect to other parts of source chamber wall in both volume sources and sources seeded with alkali metals. The roles of the plasma grid in these two kinds of sources will be described. The main functions of the plasma grid in volume sources are: optimizing the extracted negative ion current, reducing the co-extracted electron current, controlling the axial plasma potential profile, recycling the hydrogen atoms to molecules, concentrating the negative ions near its surface and, when biased positive, depleting the electron population near its surface. These functions are maintained in the sources seeded with alkali metals. However an additional function appears in the Cs seeded sources, namely direct emission of negative ions under positive ion and neutral hydrogen bombardment.

  18. Negative plasma potential in a multidipole chamber with a dielectric coated plasma boundary

    SciTech Connect (OSTI)

    Sheehan, J. P.; Hershkowitz, Noah

    2012-05-15

    Negative plasma potentials with respect to a grounded wall that was coated with a dielectric have been achieved in an electropositive plasma confined by a multidipole device. A Langmuir probe was used to measure the density and temperatures of the bi-Maxwellian distribution electrons and an emissive probe was used to measure the plasma potential profile near the plasma boundary. For many discharge parameters, the potential profile was that of a typical electropositive sheath, but it was shifted negative due to negative charge accumulated on the plasma-surface boundary. A virtual cathode was observed near the boundary when the neutral pressure, primary electron energy, and/or discharge current were low ({approx}2 x 10{sup -4} Torr, {approx}60 eV, and 80 mA, respectively). The behavior of the sheath potential was shown to be consistent with that predicted by particle balance and a qualitative mechanism for wall charging is presented.

  19. Method for resurrecting negative electron affinity photocathodes after exposure to an oxidizing gas

    DOE Patents [OSTI]

    Mulhollan, Gregory A; Bierman, John C

    2012-10-30

    A method by which negative electron affinity photocathodes (201), single crystal, amorphous, or otherwise ordered, can be made to recover their quantum yield following exposure to an oxidizing gas has been discovered. Conventional recovery methods employ the use of cesium as a positive acting agent (104). In the improved recovery method, an electron beam (205), sufficiently energetic to generate a secondary electron cloud (207), is applied to the photocathode in need of recovery. The energetic beam, through the high secondary electron yield of the negative electron affinity surface (203), creates sufficient numbers of low energy electrons which act on the reduced-yield surface so as to negate the effects of absorbed oxidizing atoms thereby recovering the quantum yield to a pre-decay value.

  20. Negative pressures and spallation in water drops subjected to nanosecond shock waves

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Stan, Claudiu A.; Willmott, Philip R.; Stone, Howard A.; Koglin, Jason E.; Liang, Mengning; Aquila, Andrew L.; Robinson, Joseph S.; Gumerlock, Karl L.; Blaj, Gabriel; Sierra, Raymond G.; et al

    2016-05-16

    Most experimental studies of cavitation in liquid water at negative pressures reported cavitation at tensions significantly smaller than those expected for homogeneous nucleation, suggesting that achievable tensions are limited by heterogeneous cavitation. We generated tension pulses with nanosecond rise times in water by reflecting cylindrical shock waves, produced by X-ray laser pulses, at the internal surface of drops of water. Depending on the X-ray pulse energy, a range of cavitation phenomena occurred, including the rupture and detachment, or spallation, of thin liquid layers at the surface of the drop. When spallation occurred, we evaluated that negative pressures below –100 MPamore » were reached in the drops. As a result, we model the negative pressures from shock reflection experiments using a nucleation-and-growth model that explains how rapid decompression could outrun heterogeneous cavitation in water, and enable the study of stretched water close to homogeneous cavitation pressures.« less

  1. Twenty Five Years of Vibrational Kinetics and Negative Ion Production in H2 Plasmas: Modelling Aspects

    SciTech Connect (OSTI)

    Capitelli, M.; De Pascale, O.; Diomede, P.; Gorse, C.; Longo, S.; Pagano, D.; Gicquel, A.; Hassouni, K.

    2005-04-06

    Different approaches to study vibrational kinetics coupled to electron one for modeling different kinds of negative ion sources are presented. In particular two types of sources are investigated. The first one is a classical negative ion source in which the plasma is generated by thermoemitted electrons; in the second one, electrons already present in the mixture are accelerated by an RF field to sufficiently high energy to ionize the gas molecules. For the first kind of ion source a new computational scheme is presented to couple heavy particle and electron kinetics. Moreover models developed for an RF inductive discharge and for a parallel plate discharge are described.

  2. Negative ion beam injection apparatus with magnetic shield and electron removal means

    DOE Patents [OSTI]

    Anderson, Oscar A.; Chan, Chun F.; Leung, Ka-Ngo

    1994-01-01

    A negative ion source is constructed to produce H.sup.- ions without using Cesium. A high percentage of secondary electrons that typically accompany the extracted H.sup.- are trapped and eliminated from the beam by permanent magnets in the initial stage of acceleration. Penetration of the magnetic field from the permanent magnets into the ion source is minimized. This reduces the destructive effect the magnetic field could have on negative ion production and extraction from the source. A beam expansion section in the extractor results in a strongly converged final beam.

  3. Modeling of a negative ion source. I. Gas kinetics and dynamics in the expansion region

    SciTech Connect (OSTI)

    Taccogna, F.; Schneider, R.; Longo, S.; Capitelli, M.

    2007-07-15

    The vibrational population distribution of the electronic ground state of H{sub 2} in the expansion region of a negative ion source is investigated using a kinetic Monte Carlo model. Operative conditions are referred to the inductively coupled plasma radio frequency negative ion source developed at IPP-Garching. The different excitation and relaxation processes are discussed, both bulk and surface contributions. In particular, due to the relatively high plasma density, the relevant role of direct low energy electron-impact excitation, surface Auger neutralization, and vibration-translation deactivation are recovered. Results of the present model will be used as input data for the neutral source model in the extraction region.

  4. Prospective Trial of High-Dose Reirradiation Using Daily Image Guidance With Intensity-Modulated Radiotherapy for Recurrent and Second Primary Head-and-Neck Cancer

    SciTech Connect (OSTI)

    Chen, Allen M.; Farwell, D. Gregory; Luu, Quang; Cheng, Suzan; Donald, Paul J.; Purdy, James A.

    2011-07-01

    Purpose: To report a single-institutional experience using intensity-modulated radiotherapy with daily image-guided radiotherapy for the reirradiation of recurrent and second cancers of the head and neck. Methods and Materials: Twenty-one consecutive patients were prospectively treated with intensity-modulated radiotherapy from February 2006 to March 2009 to a median dose of 66 Gy (range, 60-70 Gy). None of these patients received concurrent chemotherapy. Daily helical megavoltage CT scans were obtained before each fraction as part of an image-guided radiotherapy registration protocol for patient alignment. Results: The 1- and 2-year estimates of in-field control were 72% and 65%, respectively. A total of 651 daily megavoltage CT scans were obtained. The mean systematic shift to account for interfraction motion was 1.38 {+-} 1.25 mm, 1.79 {+-} 1.45 mm, and 1.98 {+-} 1.75 mm for the medial-lateral, superior-inferior, and anterior-posterior directions, respectively. Pretreatment shifts of >3 mm occurred in 19% of setups in the medial-lateral, 27% in the superior-inferior, and 33% in the anterior-posterior directions, respectively. There were no treatment-related fatalities or hospitalizations. Complications included skin desquamation, odynophagia, otitis externa, keratitis, naso-lacrimal duct stenosis, and brachial plexopathy. Conclusions: Intensity-modulated radiotherapy with daily image guidance results in effective disease control with relatively low morbidity and should be considered for selected patients with recurrent and second primary cancers of the head and neck.

  5. Unprotected daily sun exposure is differently associated with central adiposity and beta-cell dysfunction by gender: The Korean national health and nutrition examination survey (KNHANES) V

    SciTech Connect (OSTI)

    Ohn, Jung Hun; Kwon, In Ho; Park, Juri; Ryu, Ohk Hyun; Lee, Seong Jin; Kim, Doo-Man; Ihm, Sung-Hee; Choi, Moon-Gi; Yoo, Hyung Joon; Hong, Eun-Gyoung

    2014-08-15

    Background: Ultraviolet irradiation by sun exposure has been associated with both harms and benefits to metabolic health. Objective: The objective of this study was to determine whether unprotected daily sun exposure is associated with the prevalence of diabetes and explore the underlying mechanism. Methods: We analyzed the Korean National Health and Nutrition Survey V from 2010 to 2011. Participants 19–60 years of age were asked about the average amount of time they had been exposed to direct sunlight per day since the age of 19. We categorized participants into three groups with different levels of lifetime daily sun exposure and explored the association of sun exposure with the prevalence of diabetes. Results: The risk of diabetes was higher in subjects with more than 5 h of unprotected sun exposure per day, with an odds ratio of 2.39 (95% CI 1.75–3.25), compared to those with less than 2 h of sun exposure, and the association remained significant after adjusting for diabetes risk factors. Long-term sun exposure was associated with increased central obesity and the possibility of an increase in visceral adiposity, especially among women, and with decrease in beta cell function and peripheral adiposity or percent body fat in men. Conclusions: Our study provides a cutoff for upper limit of sun exposure and suggests unprotected daily sun exposure for more than 5 h should be avoided to prevent diabetes. Increased central adiposity and decreased beta cell function were observed in women and men, respectively, who had long-term unprotected daily sun exposure. - Highlights: • Sun exposure for more than 5 h per day is associated with diabetes risk. • Insulin resistance associated with visceral adiposity may play a role in women. • Insulin secretory defect may explain diabetes risk in men.

  6. Negative space charge effects in photon-enhanced thermionic emission solar converters

    SciTech Connect (OSTI)

    Segev, G.; Weisman, D.; Rosenwaks, Y.; Kribus, A.

    2015-07-06

    In thermionic energy converters, electrons in the gap between electrodes form a negative space charge and inhibit the emission of additional electrons, causing a significant reduction in conversion efficiency. However, in Photon Enhanced Thermionic Emission (PETE) solar energy converters, electrons that are reflected by the electric field in the gap return to the cathode with energy above the conduction band minimum. These electrons first occupy the conduction band from which they can be reemitted. This form of electron recycling makes PETE converters less susceptible to negative space charge loss. While the negative space charge effect was studied extensively in thermionic converters, modeling its effect in PETE converters does not account for important issues such as this form of electron recycling, nor the cathode thermal energy balance. Here, we investigate the space charge effect in PETE solar converters accounting for electron recycling, with full coupling of the cathode and gap models, and addressing conservation of both electric and thermal energy. The analysis shows that the negative space charge loss is lower than previously reported, allowing somewhat larger gaps compared to previous predictions. For a converter with a specific gap, there is an optimal solar flux concentration. The optimal solar flux concentration, the cathode temperature, and the efficiency all increase with smaller gaps. For example, for a gap of 3 μm the maximum efficiency is 38% and the optimal flux concentration is 628, while for a gap of 5 μm the maximum efficiency is 31% and optimal flux concentration is 163.

  7. Negative-mass mitigation of Coulomb repulsion for terahertz undulator radiation of electron bunches

    SciTech Connect (OSTI)

    Balal, N.; Magory, E.; Bandurkin, I. V.; Bratman, V. L.; Savilov, A. V.

    2015-10-19

    It is proposed to utilize the effect of negative mass for stabilization of the effective axial size of very dense and short electron bunches produced by photo-injector guns by using combined undulator and strong uniform magnetic fields. It has been shown that in the “abnormal” regime, an increase in the electron energy leads to a decrease in the axial velocity of the electron; due to the negative-mass effect, the Coulomb repulsion of electrons leads to their attraction and formation of a fairly stable and compact bunch “nucleus.” An undulator with a strong uniform magnetic field providing the negative-mass effect is designed for an experimental source of terahertz radiation. The use of the negative-mass regime in this experiment should result in a long-pulse coherent spontaneous undulator emission from a short dense moderately relativistic (5.5 MeV) photo-injector electron bunch with a high (up to 20%) efficiency and a narrow frequency spectrum.

  8. Lithium aluminum/iron sulfide battery having lithium aluminum and silicon as negative electrode

    DOE Patents [OSTI]

    Gilbert, Marian; Kaun, Thomas D.

    1984-01-01

    A method of making a negative electrode, the electrode made thereby and a secondary electrochemical cell using the electrode. Silicon powder is mixed with powdered electroactive material, such as the lithium-aluminum eutectic, to provide an improved electrode and cell.

  9. Method of preparing a negative electrode including lithium alloy for use within a secondary electrochemical cell

    DOE Patents [OSTI]

    Tomczuk, Zygmunt; Olszanski, Theodore W.; Battles, James E.

    1977-03-08

    A negative electrode that includes a lithium alloy as active material is prepared by briefly submerging a porous, electrically conductive substrate within a melt of the alloy. Prior to solidification, excess melt can be removed by vibrating or otherwise manipulating the filled substrate to expose interstitial surfaces. Electrodes of such as solid lithium-aluminum filled within a substrate of metal foam are provided.

  10. Comparison of measured and modelled negative hydrogen ion densities at the ECR-discharge HOMER

    SciTech Connect (OSTI)

    Rauner, D.; Kurutz, U.; Fantz, U.

    2015-04-08

    As the negative hydrogen ion density n{sub H{sup −}} is a key parameter for the investigation of negative ion sources, its diagnostic quantification is essential in source development and operation as well as for fundamental research. By utilizing the photodetachment process of negative ions, generally two different diagnostic methods can be applied: via laser photodetachment, the density of negative ions is measured locally, but only relatively to the electron density. To obtain absolute densities, the electron density has to be measured additionally, which induces further uncertainties. Via cavity ring-down spectroscopy (CRDS), the absolute density of H{sup −} is measured directly, however LOS-averaged over the plasma length. At the ECR-discharge HOMER, where H{sup −} is produced in the plasma volume, laser photodetachment is applied as the standard method to measure n{sub H{sup −}}. The additional application of CRDS provides the possibility to directly obtain absolute values of n{sub H{sup −}}, thereby successfully bench-marking the laser photodetachment system as both diagnostics are in good agreement. In the investigated pressure range from 0.3 to 3 Pa, the measured negative hydrogen ion density shows a maximum at 1 to 1.5 Pa and an approximately linear response to increasing input microwave powers from 200 up to 500 W. Additionally, the volume production of negative ions is 0-dimensionally modelled by balancing H{sup −} production and destruction processes. The modelled densities are adapted to the absolute measurements of n{sub H{sup −}} via CRDS, allowing to identify collisions of H{sup −} with hydrogen atoms (associative and non-associative detachment) to be the dominant loss process of H{sup −} in the plasma volume at HOMER. Furthermore, the characteristic peak of n{sub H{sup −}} observed at 1 to 1.5 Pa is identified to be caused by a comparable behaviour of the electron density with varying pressure, as n{sub e} determines

  11. Potential formation in a collisionless plasma produced in an open magnetic field in presence of volume negative ion source

    SciTech Connect (OSTI)

    Phukan, Ananya, E-mail: ananya.phukan26@gmail.com; Goswami, K. S.; Bhuyan, P. J. [Centre of Plasma Physics, Institute for Plasma Research Sonapur, Kamrup (M), Assam 782402 (India)

    2014-08-15

    The electric potential near a wall for a multi-species plasma with volume produced negative ions in presence of axially varying magnetic field is studied following an analytical-numerical approach. A constant negative ion source is assumed throughout the plasma volume, along with finite temperature positive ions and Boltzmann electrons. The particles are assumed to be guided by an open magnetic field that has its maximum at the centre, and field strength decreasing towards the walls. The one dimensional (1D) Poisson equation is derived using an analytical approach, and then solved numerically to study the potential profiles. Effect of (a) negative ion production rate, (b) magnetic field profile, and (c) negative ion temperature on the potential profile has been investigated. A potential peak appears near the wall when the negative ion temperature and density are sufficiently high. Also, the presence of negative ions further decreases the potential in the plasma region for a finite Debye Length (?{sub D})

  12. Negative hydrogen ion beam extraction from an AC heated cathode driven Bernas-type ion source

    SciTech Connect (OSTI)

    Okano, Y.; Miyamoto, N.; Kasuya, T.; Wada, M.

    2015-04-08

    A plasma grid structure was installed to a Bernas-type ion source used for ion implantation equipment. A negative hydrogen (H{sup −}) ion beam was extracted by an AC driven ion source by adjusting the bias to the plasma grid. The extracted electron current was reduced by positively biasing the plasma grid, while an optimum plasma grid bias voltage for negative ion beam extraction was found to be positive 3 V with respect to the arc chamber. Source operations with AC cathode heating show extraction characteristics almost identical to that with DC cathode heating, except a minute increase in H{sup −} current at higher frequency of cathode heating current.

  13. Roughening and removal of surface contamination from beryllium using negative transferred-arc cleaning

    SciTech Connect (OSTI)

    Castro, R.G.; Hollis, K.J.; Elliott, K.E.

    1997-12-01

    Negative transferred-arc (TA) cleaning has been used extensively in the aerospace industry to clean and prepare surfaces prior to plasma spraying of thermal barrier coatings. This non-line of sight process can improve the bond strength of plasma sprayed coatings to the substrate material by cleaning and macroscopically roughening the surface. A variation of this cleaning methodology is also used in gas tungsten arc (GTA) welding to cathodically clean the surfaces of aluminum and magnesium prior to welding. Investigations are currently being performed to quantify the degree in which the negative transferred-arc process can clean and roughen metal surfaces. Preliminary information will be reported on the influence of processing conditions on roughening and the removal of carbon and other contaminates from the surface of beryllium. Optical, spectral and electrical methods to quantify cleaning of the surface will also be discussed. Applications for this technology include chemical-free precision cleaning of beryllium components.

  14. Government Decision to Abandon Yucca Mountain Negatively Impacts Central Savannah River Area

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    For Immediate Release Contact: Rick McLeod Monday, November 9, 2009 803.593.9954 x1411 Government Decision to Abandon Yucca Mountain Negatively Impacts Central Savannah River Area AIKEN, SC - The Federal Government's failure to complete construction of its only option for long-term nuclear waste storage at Yucca Mountain in the Nevada desert will result in the Savannah River Site becoming the permanent home to tons of high- level nuclear waste, a local community group says. The SRS Community

  15. Observation of negative differential capacitance (NDC) in Ti Schottky diodes on SiGe islands

    SciTech Connect (OSTI)

    Rangel-Kuoppa, Victor-Tapio; Jantsch, Wolfgang; Tonkikh, Alexander; Zakharov, Nikolay; Werner, Peter

    2013-12-04

    The Negative Differential Capacitance (NDC) effect on Ti Schottky diodes formed on n-type Silicon samples with embedded Germanium Quantum Dots (QDs) is observed and reported. The NDC-effect is detected using capacitance-voltage (CV) method at temperatures below 200 K. It is explained by the capture of electrons in Germanium QDs. Our measurements reveal that each Ge QD captures in average eight electrons.

  16. Structure of the Dominant Negative S17N Mutant of Ras

    SciTech Connect (OSTI)

    Nassar, N.; Singh, K; Garcia-Diaz, M

    2010-01-01

    The use of the dominant negative mutant of Ras has been crucial in elucidating the cellular signaling of Ras in response to the activation of various membrane-bound receptors. Although several point mutants of Ras exhibit a dominant negative effect, the asparagine to serine mutation at position 17 (S17N) remains the most popular and the most effective at inhibiting the activation of endogenous Ras. It is now widely accepted that the dominant negative effect is due to the ability of the mutant to sequester upstream activators and its inability to activate downstream effectors. Here, we present the crystal structure of RasS17N in the GDP-bound form. In the three molecules that populate the asymmetric unit, the Mg{sup 2+} ion that normally coordinates the {beta}-phosphate is absent because of steric hindrance from the Asn17 side chain. Instead, a Ca{sup 2+} ion is coordinating the {alpha}-phosphate. Also absent from one molecule is electron density for Phe28, a conserved residue that normally stabilizes the nucleotide's guanine base. Except for Phe28, the nucleotide makes conserved interactions with Ras. Combined, the inability of Phe28 to stabilize the guanine base and the absence of a Mg{sup 2+} ion to neutralize the negative charges on the phosphates explain the weaker affinity of GDP for Ras. Our data suggest that the absence of the Mg{sup 2+} should also dramatically affect GTP binding to Ras and the proper positioning of Thr35 necessary for the activation of switch 1 and the binding to downstream effectors, a prerequisite for the triggering of signaling pathways.

  17. Method of preparing a negative electrode including lithium alloy for use within a secondary electrochemical cell

    DOE Patents [OSTI]

    Tomczuk, Z.; Olszanski, W.; Battles, J.E.

    1975-12-09

    A negative electrode that includes a lithium alloy as active material is prepared by briefly submerging a porous, electrically conductive substrate within a melt of the alloy. Prior to solidification, excess melt can be removed by vibrating or otherwise manipulating the filled substrate to expose interstitial surfaces. Electrodes of such a solid lithium--aluminum filled within a substrate of metal foam are provided. 1 figure, 1 table.

  18. Low energy milling method, low crystallinity alloy, and negative electrode composition

    DOE Patents [OSTI]

    Le, Dihn B; Obrovac, Mark N; Kube, Robert Y; Landucci, James R

    2012-10-16

    A method of making nanostructured alloy particles includes milling a millbase in a pebble mill containing milling media. The millbase comprises: (i) silicon, and (ii) at least one of carbon or a transition metal, and wherein the nanostructured alloy particles are substantially free of crystalline domains greater than 50 nanometers in size. A method of making a negative electrode composition for a lithium ion battery including the nanostructured alloy particles is also disclosed.

  19. Hydridable material for the negative electrode in a nickel-metal hydride storage battery

    DOE Patents [OSTI]

    Knosp, Bernard; Bouet, Jacques; Jordy, Christian; Mimoun, Michel; Gicquel, Daniel

    1997-01-01

    A monophase hydridable material for the negative electrode of a nickel-metal hydride storage battery with a "Lave's phase" structure of hexagonal C14 type (MgZn.sub.2) has the general formula: Zr.sub.1-x Ti.sub.x Ni.sub.a Mn.sub.b Al.sub.c Co.sub.d V.sub.e where ##EQU1##

  20. Volume generation of negative ions in high density hydrogen discharges. Revision 1

    SciTech Connect (OSTI)

    Hiskes, J.R.; Karo, A.M.

    1983-11-11

    An optimized tandem two-chamber negative-ion source system is discussed. In the first chamber high energy (E > 20 eV) electron collisions provide for H/sub 2/ vibrational excitation, while in the second chamber negative ions are formed by dissociative attachment. The gas density, electron density, and system scale length are varied as independent parameters. The extracted negative ion current density passes through a maximum as electron and gas densities are varied. This maximum scales inversely with system scale length, R. The optimum extracted current densities occur for electron densities near nR = 10/sup 13/ electrons cm/sup -2/ and for gas densities, N/sub 2/R, in the range 10/sup 14/ to 10/sup 15/ molecules cm/sup -2/. The extracted current densities are sensitive to the atomic concentration in the discharge. The atomic concentration is parametrized by the wall recombination coefficient, ..gamma.., and scale length, R. As ..gamma.. ranges from 0.1 to 1.0 and for system scale lengths of one centimeter, extracted current densities range from 8.0 to 80. mA cm/sup -2/.

  1. Application Of The Phase Shifting Diffraction Interferometer For Measuring Convex Mirrors And Negative Lenses

    DOE Patents [OSTI]

    Sommargren, Gary E.; Campbell, Eugene W.

    2005-06-21

    To measure a convex mirror, a reference beam and a measurement beam are both provided through a single optical fiber. A positive auxiliary lens is placed in the system to give a converging wavefront onto the convex mirror under test. A measurement is taken that includes the aberrations of the convex mirror as well as the errors due to two transmissions through the positive auxiliary lens. A second measurement provides the information to eliminate this error. A negative lens can also be measured in a similar way. Again, there are two measurement set-ups. A reference beam is provided from a first optical fiber and a measurement beam is provided from a second optical fiber. A positive auxiliary lens is placed in the system to provide a converging wavefront from the reference beam onto the negative lens under test. The measurement beam is combined with the reference wavefront and is analyzed by standard methods. This measurement includes the aberrations of the negative lens, as well as the errors due to a single transmission through the positive auxiliary lens. A second measurement provides the information to eliminate this error.

  2. Evaluation of Negative-Ion-Beam Driver Concepts for Heavy Ion Fusion

    SciTech Connect (OSTI)

    Grisham, Larry R.

    2003-03-15

    The feasibility of producing and using atomically neutral heavy ion beams produced from negative ions as drivers for an inertial confinement fusion reactor is evaluated. Bromine and iodine appear to be the most attractive elements for the driver beams. Fluorine and chlorine appear to be the most appropriate feedstocks for initial tests of extractable negative-ion current densities. With regard to ion sources, photodetachment neutralizers, and vacuum requirements for accelerators and beam transport, this approach appears feasible within existing technology, and the vacuum requirements are essentially identical to those for positive-ion drivers except in the target chamber. The principal constraint is that this approach requires harder vacuums in the target chamber than do space-charge-neutralized positive-ion drivers. With realistic (but perhaps pessimistic) estimates of the total ionization cross section, limiting the ionization of a neutral beam to <5% while traversing a 3-m path would require a chamber pressure of no more than 1.3 x 10{sup -5} torr. However, it appears that substantial improvements in the beam spot size on target might be achieved at pressures a factor of 10 or more higher than this. Alternatively, even at still higher chamber pressures that would strongly ionize atomically neutral beams, the negative-ion approach may still have significant appeal, since it precludes the possibly challenging problem of electron contamination of a positive-ion beam during acceleration, drift compression, and focusing.

  3. Evaluation of Negative-Ion-Beam Driver Concepts for Heavy Ion Fusion

    SciTech Connect (OSTI)

    Larry R. Grisham

    2002-01-14

    We evaluate the feasibility of producing and using atomically neutral heavy ion beams produced from negative ions as drivers for an inertial confinement fusion reactor. Bromine and iodine appear to be the most attractive elements for the driver beams. Fluorine and chlorine appear to be the most appropriate feedstocks for initial tests of extractable negative ion current densities. With regards to ion sources, photodetachment neutralizers, and vacuum requirements for accelerators and beam transport, this approach appears feasible within existing technology, and the vacuum requirements are essentially identical to those for positive ion drivers except in the target chamber. The principal constraint is that this approach requires harder vacuums in the target chamber than do space-charge-neutralized positive ion drivers. With realistic (but perhaps pessimistic) estimates of the total ionization cross section, limiting the ionization of a neutral beam to less than 5% while traversing a four -meter path would require a chamber pressure of no more than 5 x 10{sup -5} torr. Alternatively, even at chamber pressures that are too high to allow propagation of atomically neutral beams, the negative ion approach may still have appeal, since it precludes the possibly serious problem of electron contamination of a positive ion beam during acceleration, drift compression, and focusing.

  4. Landau damping effects on dust-acoustic solitary waves in a dusty negative-ion plasma

    SciTech Connect (OSTI)

    Barman, Arnab; Misra, A. P. E-mail: apmisra@gmail.com

    2014-07-15

    The nonlinear theory of dust-acoustic waves (DAWs) with Landau damping is studied in an unmagnetized dusty negative-ion plasma in the extreme conditions when the free electrons are absent. The cold massive charged dusts are described by fluid equations, whereas the two-species of ions (positive and negative) are described by the kinetic Vlasov equations. A Korteweg-de Vries (KdV) equation with Landau damping, governing the dynamics of weakly nonlinear and weakly dispersive DAWs, is derived following Ott and Sudan [Phys. Fluids 12, 2388 (1969)]. It is shown that for some typical laboratory and space plasmas, the Landau damping (and the nonlinear) effects are more pronounced than the finite Debye length (dispersive) effects for which the KdV soliton theory is not applicable to DAWs in dusty pair-ion plasmas. The properties of the linear phase velocity, solitary wave amplitudes (in presence and absence of the Landau damping) as well as the Landau damping rate are studied with the effects of the positive ion to dust density ratio (?{sub pd}) as well as the ratios of positive to negative ion temperatures (?) and masses (m)

  5. Multi-dipolar microwave plasmas and their application to negative ion production

    SciTech Connect (OSTI)

    Bchu, S.; Bs, A.; Lacoste, A.; Aleiferis, S.; Ivanov, A. A. Jr.; Bacal, M.

    2013-10-15

    During the past decade multi-dipolar plasmas have been employed for various purposes such as surface treatments in biomedicine, physical and chemical vapour deposition for hydrogen storage, and applications in mechanical engineering. On the other hand, due to the design and operational mode of these plasma sources (i.e., strong permanent magnets for the electron cyclotron resonance coupling, low working pressure, and high electron density achieved) they are suitable for studying fundamental mechanisms involved in negative ion sources used in magnetically confined fusion and particle accelerators. Thus, this study presents an overview of fundamental results obtained with: (i) a single dipolar source, (ii) a network of seven dipolar plasma sources inserted into a magnetic multipolar chamber (Camembert III), and (iii) four dipolar sources housed in a smaller metallic cylinder (ROSAE III). Investigations with Langmuir probes of electron energy probability functions revealed the variation of the plasma properties versus the radial distance from the axis of a dipolar source in its mid plane and allowed the determination of the proportion between hot and cold electron populations in both chambers. These results are compared with the density of hydrogen negative ions, measured using the photodetachment technique. Electron energy probability functions obtained in these different configurations show the possibility of both hot and cold electron production. The former is a prerequisite for increasing the vibrational level of molecules and the dissociation degree and the latter for producing negative ions via dissociative attachment of the cold electrons or via surface production induced by H atoms.

  6. Application of the phase shifting diffraction interferometer for measuring convex mirrors and negative lenses

    DOE Patents [OSTI]

    Sommargren, Gary E.; Campbell, Eugene W.

    2004-03-09

    To measure a convex mirror, a reference beam and a measurement beam are both provided through a single optical fiber. A positive auxiliary lens is placed in the system to give a converging wavefront onto the convex mirror under test. A measurement is taken that includes the aberrations of the convex mirror as well as the errors due to two transmissions through the positive auxiliary lens. A second, measurement provides the information to eliminate this error. A negative lens can also be measured in a similar way. Again, there are two measurement set-ups. A reference beam is provided from a first optical fiber and a measurement beam is provided from a second optical fiber. A positive auxiliary lens is placed in the system to provide a converging wavefront from the reference beam onto the negative lens under test. The measurement beam is combined with the reference wavefront and is analyzed by standard methods. This measurement includes the aberrations of the negative lens, as well as the errors due to a single transmission through the positive auxiliary lens. A second measurement provides the information to eliminate this error.

  7. The development of the radio frequency driven negative ion source for neutral beam injectors (invited)

    SciTech Connect (OSTI)

    Kraus, W.; Fantz, U.; Franzen, P.; Froeschle, M.; Heinemann, B.; Riedl, R.; Wuenderlich, D.

    2012-02-15

    Large and powerful negative hydrogen ion sources are required for the neutral beam injection (NBI) systems of future fusion devices. Simplicity and maintenance-free operation favors RF sources, which are developed intensively at the Max-Planck-Institut fuer Plasmaphysik (IPP) since many years. The negative hydrogen ions are generated by caesium-enhanced surface conversion of atoms and positive ions on the plasma grid surface. With a small scale prototype the required high ion current density and the low fraction of co-extracted electrons at low pressure as well as stable pulses up to 1 h could be demonstrated. The modular design allows extension to large source dimensions. This has led to the decision to choose RF sources for the NBI of the international fusion reactor, ITER. As an intermediate step towards the full size ITER source at IPP, the development will be continued with a half-size source on the new ELISE testbed. This will enable to gain experience for the first time with negative hydrogen ion beams from RF sources of these dimensions.

  8. Aerodynamic Sensitivity Analysis of Rotor Imbalance and Shear...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Health Prognostics Management of Wind Turbine Blades Noah J. Myrent 1 and Douglas E. ... and how these changes manifest themselves in the operational response of a full turbine. ...

  9. Network for minimizing current imbalances in a faradaic battery

    DOE Patents [OSTI]

    Wozniak, Walter; Haskins, Harold J.

    1994-01-01

    A circuit for connecting a faradaic battery with circuitry for monitoring the condition of the battery includes a plurality of voltage divider networks providing battery voltage monitoring nodes and includes compensating resistors connected with the networks to maintain uniform discharge currents through the cells of the battery. The circuit also provides a reduced common mode voltage requirement for the monitoring circuitry by referencing the divider networks to one-half the battery voltage.

  10. Flexibility Reserve Reductions from an Energy Imbalance Market...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ... 300- 620 Load Following or Fast Energy Markets Similar to regulation but slower. Bridges between the regulation service and the hourly energy markets. 10 min 10 min to hours ...

  11. Effect of Divalent Cation Removal on the Structure of Gram-Negative Bacterial Outer Membrane Models

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Clifton, Luke A.; Skoda, Maximilian W. A.; Le Brun, Anton P.; Ciesielski, Filip; Kuzmenko, Ivan; Holt, Stephen A.; Lakey, Jeremy H.

    2014-12-09

    The Gram-negative bacterial outer membrane (GNB-OM) is asymmetric in its lipid composition with a phospholipid-rich inner leaflet and an outer leaflet predominantly composed of lipopolysaccharides (LPS). LPS are polyanionic molecules, with numerous phosphate groups present in the lipid A and core oligosaccharide regions. The repulsive forces due to accumulation of the negative charges are screened and bridged by the divalent cations (Mg2+ and Ca2+) that are known to be crucial for the integrity of the bacterial OM. Indeed, chelation of divalent cations is a well-established method to permeabilize Gram-negative bacteria such as Escherichia coli. Here, we use X-ray and neutronmore » reflectivity (XRR and NR, respectively) techniques to examine the role of calcium ions in the stability of a model GNB-OM. Using XRR we show that Ca2+ binds to the core region of the rough mutant LPS (RaLPS) films, producing more ordered structures in comparison to divalent cation free monolayers. Using recently developed solid-supported models of the GNB-OM, we study the effect of calcium removal on the asymmetry of DPPC:RaLPS bilayers. We show that without the charge screening effect of divalent cations, the LPS is forced to overcome the thermodynamically unfavorable energy barrier and flip across the hydrophobic bilayer to minimize the repulsive electrostatic forces, resulting in about 20% mixing of LPS and DPPC between the inner and outer bilayer leaflets. These results reveal for the first time the molecular details behind the well-known mechanism of outer membrane stabilization by divalent cations. This confirms the relevance of the asymmetric models for future studies of outer membrane stability and antibiotic penetration.« less

  12. Effect of Divalent Cation Removal on the Structure of Gram-Negative Bacterial Outer Membrane Models

    SciTech Connect (OSTI)

    Clifton, Luke A.; Skoda, Maximilian W. A.; Le Brun, Anton P.; Ciesielski, Filip; Kuzmenko, Ivan; Holt, Stephen A.; Lakey, Jeremy H.

    2014-12-09

    The Gram-negative bacterial outer membrane (GNB-OM) is asymmetric in its lipid composition with a phospholipid-rich inner leaflet and an outer leaflet predominantly composed of lipopolysaccharides (LPS). LPS are polyanionic molecules, with numerous phosphate groups present in the lipid A and core oligosaccharide regions. The repulsive forces due to accumulation of the negative charges are screened and bridged by the divalent cations (Mg2+ and Ca2+) that are known to be crucial for the integrity of the bacterial OM. Indeed, chelation of divalent cations is a well-established method to permeabilize Gram-negative bacteria such as Escherichia coli. Here, we use X-ray and neutron reflectivity (XRR and NR, respectively) techniques to examine the role of calcium ions in the stability of a model GNB-OM. Using XRR we show that Ca2+ binds to the core region of the rough mutant LPS (RaLPS) films, producing more ordered structures in comparison to divalent cation free monolayers. Using recently developed solid-supported models of the GNB-OM, we study the effect of calcium removal on the asymmetry of DPPC:RaLPS bilayers. We show that without the charge screening effect of divalent cations, the LPS is forced to overcome the thermodynamically unfavorable energy barrier and flip across the hydrophobic bilayer to minimize the repulsive electrostatic forces, resulting in about 20% mixing of LPS and DPPC between the inner and outer bilayer leaflets. These results reveal for the first time the molecular details behind the well-known mechanism of outer membrane stabilization by divalent cations. This confirms the relevance of the asymmetric models for future studies of outer membrane stability and antibiotic penetration.

  13. PKC{eta} is a negative regulator of AKT inhibiting the IGF-I induced proliferation

    SciTech Connect (OSTI)

    Shahaf, Galit; Rotem-Dai, Noa; Koifman, Gabriela; Raveh-Amit, Hadas; Frost, Sigal A.; Livneh, Etta

    2012-04-15

    The PI3K-AKT pathway is frequently activated in human cancers, including breast cancer, and its activation appears to be critical for tumor maintenance. Some malignant cells are dependent on activated AKT for their survival; tumors exhibiting elevated AKT activity show sensitivity to its inhibition, providing an Achilles heel for their treatment. Here we show that the PKC{eta} isoform is a negative regulator of the AKT signaling pathway. The IGF-I induced phosphorylation on Ser473 of AKT was inhibited by the PKC{eta}-induced expression in MCF-7 breast adenocarcinoma cancer cells. This was further confirmed in shRNA PKC{eta}-knocked-down MCF-7 cells, demonstrating elevated phosphorylation on AKT Ser473. While PKC{eta} exhibited negative regulation on AKT phosphorylation it did not alter the IGF-I induced ERK phosphorylation. However, it enhanced ERK phosphorylation when stimulated by PDGF. Moreover, its effects on IGF-I/AKT and PDGF/ERK pathways were in correlation with cell proliferation. We further show that both PKC{eta} and IGF-I confer protection against UV-induced apoptosis and cell death having additive effects. Although the protective effect of IGF-I involved activation of AKT, it was not affected by PKC{eta} expression, suggesting that PKC{eta} acts through a different route to increase cell survival. Hence, our studies show that PKC{eta} provides negative control on AKT pathway leading to reduced cell proliferation, and further suggest that its presence/absence in breast cancer cells will affect cell death, which could be of therapeutic value.

  14. Design of the new extraction grid for the NIO1 negative ion source

    SciTech Connect (OSTI)

    Veltri, P. Baltador, C.; Cavenago, M.

    2015-04-08

    NIO1 is a compact source of negative ions jointly developed by RFX and INFN, to study the physics of production and acceleration of H{sup −} beams. Negative ions, up to 120 mA of current, are extracted from a radiofrequency driven plasma, by means of a gridded electrode (plasma grid, PG) featuring 9 apertures arranged in a 3x3 square lattice. The same aperture pattern is replicated in the following electrodes, allowing ion acceleration up to 60 keV. All electrodes are realized in copper, by electro-deposition technique, leaving empty slots in the metal to place magnets and to flow water for the grid cooling. The first set of electrodes was completed, installed in the source and tested. At the same time, an upgrade of the extraction system was carried out, in order to optimize the beam optics and to explore alternative electrostatic configurations. In particular, the accelerator will be modified by completely replacing the EG grid, exploiting the modularity of NIO1. The new electrode will feature other slots in between apertures, to place additional magnets. This allows testing different magnetic configurations, to optimize electron filtering and residual ion deflection. The present paper describes the theoretical activities driving the design of these new extractors, carried out with most updated numerical codes, and exploiting the synergy with the refined modeling of the 40 A ITER negative ion sources, under development at Consorzio RFX. Beam simulations are performed both with tracing codes (SLACCAD and OPERA) and with particle in cell codes (ACCPIC)

  15. Recent Progress in the Negative-Ion-Based Neutral Beam Injectors in Large Helical Device

    SciTech Connect (OSTI)

    Takeiri, Y.; Tsumori, K.; Ikeda, K.; Osakabe, M.; Nagaoka, K.; Oka, Y.; Asano, E.; Kondo, T.; Sato, M.; Shibuya, M.; Komada, S.; Kaneko, O.

    2009-03-12

    Negative-ion-based neutral beam injection (negative-NBI) system has been operated for 10 years in Large Helical Device (LHD). The injection power has been increased year by year, according to the improvement of the negative ion sources. Up to now, every injector achieves the designed injection energy and power of 180 keV-5 MW with hydrogen beams, and the total injection power exceeds 16 MW with three injectors. In the multi-round aperture grounded grid (GG), the diameter of a round aperture has been enlarged for higher GG transparency. Then, the GG heat load is reduced, as well as in the multi-slotted GG, and the voltage holding ability in the beam acceleration was improved. As a result, the beam energy is raised and the injection power is increased. To improve the anisotropic property of the beamlet convergence condition between the perpendicular and the parallel directions to the slots in the multi-slotted GG, a round-shape aperture of the steering grid (SG) has been changed to a racetrack shape. As a result, the difference of the beamlet conversion condition is much mitigated, and the injection efficiency (port-transmission efficiency) is improved, leading to 188 keV-6.4 MW injection. The Cs consumption is observed to be proportional to the tungsten evaporation from filaments. The Cs behavior is investigated with optical emission spectroscopy. During the beam extraction, the Cs recycling is dominated by Cs on the backplate, which is evaporated into the plasma by the backstreaming positive ions, and the wall surfaces should be loss regions for the supplied Cs.

  16. Three-Body Recombination of {sup 6}Li Atoms with Large Negative Scattering Lengths

    SciTech Connect (OSTI)

    Braaten, Eric; Kang, Daekyoung; Platter, Lucas; Hammer, H.-W.

    2009-08-14

    The three-body recombination rate at threshold for distinguishable atoms with large negative pair scattering lengths is calculated in the zero-range approximation. The only parameters in this limit are the 3 scattering lengths and the Efimov parameter, which can be complex-valued. We provide semianalytic expressions for the cases of 2 or 3 equal scattering lengths, and we obtain numerical results for the general case of 3 different scattering lengths. Our general result is applied to the three lowest hyperfine states of {sup 6}Li atoms. Comparisons with recent experiments provide indications of loss features associated with Efimov trimers near the 3-atom threshold.

  17. Triangular lattice of carbon nanotube arrays for negative index of refraction and subwavelength lensing effect

    SciTech Connect (OSTI)

    Wang, Y.; Wang, X.; Rybczynski, J.; Wang, D.Z.; Kempa, K.; Ren, Z.F.

    2005-04-11

    Self-assembly of polystyrene microspheres has been utilized in a two-step masking technique to prepare triangular lattices of catalytic nanodots at low cost. Subsequent triangular lattices of aligned carbon nanotubes on a silicon substrate are achieved by plasma-enhanced chemical vapor deposition. Nickel is used both in the nanodots and in the secondary mask. The triangular lattices of carbon nanotube arrays as two-dimensional photonic crystals show higher geometrical symmetry than the hexagonal lattices previously reported, enabling broader applications including negative index of refraction and subwavelength lensing effect.

  18. Experimental evidence of negative linear compressibility in the MIL-53 metal–organic framework family

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Serra-Crespo, Pablo; Dikhtiarenko, Alla; Stavitski, Eli; Juan-Alcañiz, Jana; Kapteijn, Freek; Coudert, François-Xavier; Gascon, Jorge

    2014-03-24

    Here we report a series of powder X-ray diffraction experiments performed on the soft porous crystals MIL-53(Al) and NH2-MIL-53(Al) in a diamond anvil cell under different pressurization media. Systematic refinements of the obtained powder patterns demonstrate that these materials expand along a specific direction while undergoing total volume reduction under an increasing hydrostatic pressure. The results confirm for the first time the negative linear compressibility behaviour of this family of materials, recently predicted from quantum chemical calculations.

  19. Partial Decay Widths of Negative Parity Baryons in the 1/N{sub c} Expansion

    SciTech Connect (OSTI)

    Gonzalez de Urreta, Emiliano; Scoccola, Norberto; Jayalath, Chandala; Goity, Jose

    2013-04-01

    The partial decay widths of lowest lying negative parity baryons belonging to the 70-plet of SU(6) are analyzed in the framework of the 1/N{sub c} expansion. The channels considered are those with single pseudoscalar meson emission. The analysis is carried out to sub-leading order in 1/N{sub c} and to first order in SU(3) symmetry breaking. Conclusions about the magnitude of SU(3) breaking effects along with predictions for some unknown or poorly determined partial decay widths of known resonances are given.

  20. Experimental Evidence of Negative Linear Compressibility in the MIL-53 Metal-Organic Framework Family

    SciTech Connect (OSTI)

    Serra-Crespo, Pablo; Dikhtiarenko, Alla; Stavitski, Eli; Juan-Alcaniz, Jana; Kapeteijn, Freek; Coudert, Francois-Xavier; Gascon, Jorge

    2014-03-24

    Here, we report a series of powder X-ray diffraction experiments performed on the soft porous crystals MIL-53(Al) and NH2-MIL-53(Al) in a diamond anvil cell under different pressurization media. Systematic refinements of the obtained powder patterns demonstrate that these materials expand along a specific direction while undergoing total volume reduction under an increasing hydrostatic pressure. Our results confirm for the first time the negative linear compressibility behaviour of this family of materials, recently predicted from quantum chemical calculations.

  1. Experimental Evidence of Negative Linear Compressibility in the MIL-53 Metal-organic Framework Family

    SciTech Connect (OSTI)

    Serra-Crespo, Pablo; Dikhtiarenko, Alla; Stavitski, Eli; Juan-Alcaniz, Jana; Kapteijn, Freek; Coudert, Francois-Xavier; Gascon, Jorge

    2014-03-24

    Here we report a series of powder X-ray diffraction experiments performed on the soft porous crystals MIL-53(Al) and NH2-MIL-53(Al) in a diamond anvil cell under different pressurization media. Systematic refinements of the obtained powder patterns demonstrate that these materials expand along a specific direction while undergoing total volume reduction under an increasing hydrostatic pressure. Our results confirm for the first time the negative linear compressibility behaviour of this family of materials, recently predicted from quantum chemical calculations.

  2. Method and apparatus for efficient photodetachment and purification of negative ion beams

    DOE Patents [OSTI]

    Beene, James R.; Liu, Yuan; Havener, Charles C.

    2008-02-26

    Methods and apparatus are described for efficient photodetachment and purification of negative ion beams. A method of purifying an ion beam includes: inputting the ion beam into a gas-filled multipole ion guide, the ion beam including a plurality of ions; increasing a laser-ion interaction time by collisional cooling the plurality of ions using the gas-filled multipole ion guide, the plurality of ions including at least one contaminant; and suppressing the at least one contaminant by selectively removing the at least one contaminant from the ion beam by electron photodetaching at least a portion of the at least one contaminant using a laser beam.

  3. Partial decay widths of negative parity baryons in the 1/N{sub c} expansion

    SciTech Connect (OSTI)

    Gonzalez de Urreta, E. J.; Scoccola, N. N.; Jayalath, C. P.; Goity, J. L.

    2013-03-25

    The partial decay widths of lowest lying negative parity baryons belonging to the 70-plet of SU(6) are analyzed in the framework of the 1/N{sub c} expansion. The channels considered are those with single pseudoscalar meson emission. The analysis is carried out to sub-leading order in 1/N{sub c} and to first order in SU(3) symmetry breaking. Conclusions about the magnitude of SU(3) breaking effects along with predictions for some unknown or poorly determined partial decay widths of known resonances are given.

  4. Negative parity baryon decays in the 1/N{sub c} expansion

    SciTech Connect (OSTI)

    Jayalath, C.; Goity, J. L.; Gonzalez de Urreta, E.; Scoccola, N. N.

    2011-10-01

    The partial decay widths of lowest lying negative parity baryons belonging to the 70-plet of SU(6) are analyzed in the framework of the 1/N{sub c} expansion. The channels considered are those with single pseudoscalar meson emission. The analysis is carried out to sub-leading order in 1/N{sub c} and to first order in SU(3) symmetry breaking. Conclusions about the magnitude of SU(3) breaking effects along with predictions for some unknown or poorly determined partial decay widths of known resonances are obtained.

  5. Arc plasma generator of atomic driver for steady-state negative ion source

    SciTech Connect (OSTI)

    Ivanov, A. A.; Belchenko, Yu. I.; Davydenko, V. I.; Novosibirsk State University, Novosibirsk ; Ivanov, I. A.; Kolmogorov, V. V.; Listopad, A. A. Mishagin, V. V.; Shulzhenko, G. I.; Putvinsky, S. V.; Smirnov, A.

    2014-02-15

    The paper reviews the results of development of steady-state arc-discharge plasma generator with directly heated LaB{sub 6} cathode. This arc-discharge plasma generator produces a plasma jet which is to be converted into an atomic one after recombination on a metallic plate. The plate is electrically biased relative to the plasma in order to control the atom energies. Such an intensive jet of hydrogen atoms can be used in negative ion sources for effective production of negative ions on a cesiated surface of plasma grid. All elements of the plasma generator have an augmented water cooling to operate in long pulse mode or in steady state. The thermo-mechanical stresses and deformations of the most critical elements of the plasma generator were determined by simulations. Magnetic field inside the discharge chamber was optimized to reduce the local power loads. The first tests of the steady-state arc plasma generator prototype have performed in long-pulse mode.

  6. Negative thermal expansion and anomalies of heat capacity of LuB50 at low temperatures

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Novikov, V. V.; Zhemoedov, N. A.; Matovnikov, A. V.; Mitroshenkov, N. V.; Kuznetsov, S. V.; Bud'ko, S. L.

    2015-07-20

    Heat capacity and thermal expansion of LuB50 boride were experimentally studied in the 2–300 K temperature range. The data reveal an anomalous contribution to the heat capacity at low temperatures. The value of this contribution is proportional to the first degree of temperature. It was identified that this anomaly in heat capacity is caused by the effect of disorder in the LuB50 crystalline structure and it can be described in the soft atomic potential model (SAP). The parameters of the approximation were determined. The temperature dependence of LuB50 heat capacity in the whole temperature range was approximated by the summore » of SAP contribution, Debye and two Einstein components. The parameters of SAP contribution for LuB50 were compared to the corresponding values for LuB66, which was studied earlier. Negative thermal expansion at low temperatures was experimentally observed for LuB50. The analysis of the experimental temperature dependence for the Gruneisen parameter of LuB50 suggested that the low-frequency oscillations, described in SAP mode, are responsible for the negative thermal expansion. As a result, the glasslike character of the behavior of LuB50 thermal characteristics at low temperatures was confirmed.« less

  7. An adaptive grid refinement strategy for the simulation of negative streamers

    SciTech Connect (OSTI)

    Montijn, C. . E-mail: carolynne.montijn@cwi.nl; Hundsdorfer, W. . E-mail: willem.hundsdorfer@cwi.nl; Ebert, U. . E-mail: ute.ebert@cwi.nl

    2006-12-10

    The evolution of negative streamers during electric breakdown of a non-attaching gas can be described by a two-fluid model for electrons and positive ions. It consists of continuity equations for the charged particles including drift, diffusion and reaction in the local electric field, coupled to the Poisson equation for the electric potential. The model generates field enhancement and steep propagating ionization fronts at the tip of growing ionized filaments. An adaptive grid refinement method for the simulation of these structures is presented. It uses finite volume spatial discretizations and explicit time stepping, which allows the decoupling of the grids for the continuity equations from those for the Poisson equation. Standard refinement methods in which the refinement criterion is based on local error monitors fail due to the pulled character of the streamer front that propagates into a linearly unstable state. We present a refinement method which deals with all these features. Tests on one-dimensional streamer fronts as well as on three-dimensional streamers with cylindrical symmetry (hence effectively 2D for numerical purposes) are carried out successfully. Results on fine grids are presented, they show that such an adaptive grid method is needed to capture the streamer characteristics well. This refinement strategy enables us to adequately compute negative streamers in pure gases in the parameter regime where a physical instability appears: branching streamers.

  8. Ion-acoustic solitons in negative ion plasma with two-electron temperature distributions

    SciTech Connect (OSTI)

    Mishra, M. K.; Tiwari, R. S.; Chawla, J. K.

    2012-06-15

    Ion-acoustic solitons in a warm positive and negative ion species with different masses, concentrations, and charge states with two electron temperature distributions are studied. Using reductive perturbation method, Korteweg de-Vries (KdV) and modified-KdV (m-KdV) equations are derived for the system. The soliton solution of the KdV and m-KdV equations is discussed in detail. It is found that if the ions have finite temperatures, then there exist two types of modes, namely slow and fast ion-acoustic modes. It is also investigated that the parameter determining the nature of soliton (i.e., whether the system will support compressive or rarefactive solitons) is different for slow and fast modes. For the slow mode, the parameter is the relative temperature of the two ion species; whereas for the fast mode, it is the relative concentration of the two ion species. At a critical concentration of negative ions, both compressive and rarefactive solitons coexist. The amplitude and width of the solitons are discussed in detail at critical concentration for m-KdV solitons. The effect of the relative temperature of the two-electron and cold-electron concentration on the characteristics of the solitons are also discussed.

  9. Negative thermal expansion and anomalies of heat capacity of LuB 50 at low temperatures

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Novikov, V. V.; Zhemoedov, N. A.; Matovnikov, A. V.; Mitroshenkov, N. V.; Kuznetsov, S. V.; Bud'ko, S. L.

    2015-07-20

    Heat capacity and thermal expansion of LuB50 boride were experimentally studied in the 2300 K temperature range. The data reveal an anomalous contribution to the heat capacity at low temperatures. The value of this contribution is proportional to the first degree of temperature. It was identified that this anomaly in heat capacity is caused by the effect of disorder in the LuB50crystalline structure and it can be described in the soft atomic potential model (SAP). The parameters of the approximation were determined. The temperature dependence of LuB50 heat capacity in the whole temperature range was approximated by the sum ofmoreSAP contribution, Debye and two Einstein components. The parameters of SAP contribution for LuB50 were compared to the corresponding values for LuB66, which was studied earlier. Negative thermal expansion at low temperatures was experimentally observed for LuB50. The analysis of the experimental temperature dependence for the Gruneisen parameter of LuB50 suggested that the low-frequency oscillations, described in SAP mode, are responsible for the negative thermal expansion. Thus, the glasslike character of the behavior of LuB50 thermal characteristics at low temperatures was confirmed.less

  10. A rapid compression machine study of the oxidation of propane in the negative temperature coefficient regime

    SciTech Connect (OSTI)

    Gallagher, S.M.; Curran, H.J.; Metcalfe, W.K.; Healy, D.; Simmie, J.M.; Bourque, G.

    2008-04-15

    The oxidation of propane has been studied in the temperature range 680-970 K at compressed gas pressures of 21, 27, and 37 atm and at varying equivalence ratios of 0.5, 1.0, and 2.0. These data are consistent with other experiments presented in the literature for alkane fuels in that, when ignition delay times are plotted as a function of temperature, a characteristic negative coefficient behavior is observed. In addition, these data were simulated using a detailed chemical kinetic model. It was found that qualitatively the model correctly simulated the effect of change in equivalence ratio and pressure, predicting that fuel-rich, high-pressure mixtures ignite fastest, while fuel-lean, low-pressure mixtures ignite slowest. Moreover, reactivity as a function of temperature is well captured, with the model predicting negative temperature coefficient behavior similar to the experiments. Quantitatively the model is faster than experiment for all mixtures at the lowest temperatures (650-750 K) and is also faster than experiment throughout the entire temperature range for fuel-lean mixtures. (author)