National Library of Energy BETA

Sample records for in-ocean observations cxs

  1. Publication in Ocean Engineering

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

    ... Current EC Partnerships How to Partner Small Business Vouchers Pilot at Sandia National Laboratories Social Twitter Google + Vimeo GovDelivery SlideShare Publication in Ocean ...

  2. Global warming and changes in ocean circulation

    SciTech Connect (OSTI)

    Duffy, P.B.; Caldeira, K.C.

    1998-02-01

    This final report provides an overview of the goals and accomplishments of this project. Modeling and observational work has raised the possibility that global warming may cause changes in the circulation of the ocean. If such changes would occur they could have important climatic consequences. The first technical goal of this project was to investigate some of these possible changes in ocean circulation in a quantitative way, using a state-of -the-art numerical model of the ocean. Another goal was to develop our ocean model, a detailed three-dimensional numerical model of the ocean circulation and ocean carbon cycles. A major non-technical goal was to establish LLNL as a center of excellence in modelling the ocean circulation and carbon cycle.

  3. Observation

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

    Velocity-Independent Electron Transport in the Reversed Field Pinch R. O'Connell, * D. J. Den Hartog, C. B. Forest, J. K. Anderson, T. M. Biewer, † B. E. Chapman, D. Craig, G. Fiksel, S. C. Prager, J. S. Sarff, and S. D. Terry ‡ Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA R.W. Harvey CompX, San Diego, California, USA (Received 16 December 2002; published 24 July 2003) Confinement of runaway electrons has been observed for the first time in a reversed

  4. mhtml:file://H:\CATX\APPROVED-CXS\EERE FOA 1201 - Rankine Cycle

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

    Eaton Corporation STATE: WI PROJECT TITLE : Affordable Rankine Cycle Waste Heat Recovery for Heavy Duty Trucks Funding Opportunity Announcement Number Procurement Instrument Number NEPA Control Number CID Number DE-FOA-0001201 DE-EE0007286 Based on my review of the information concerning the proposed action, as NEPA Compliance Officer (authorized under DOE Order 451.1A), I have made the following determination: CX, EA, EIS APPENDIX AND NUMBER: Description: B3.6 Small-scale research and

  5. FINAL TECHNICAL REPORT-THE ECOLOGY AND GENOMICS OF CO2 FIXATIION IN OCEANIC

    Office of Scientific and Technical Information (OSTI)

    RIVER PLUMES (Technical Report) | SciTech Connect Technical Report: FINAL TECHNICAL REPORT-THE ECOLOGY AND GENOMICS OF CO2 FIXATIION IN OCEANIC RIVER PLUMES Citation Details In-Document Search Title: FINAL TECHNICAL REPORT-THE ECOLOGY AND GENOMICS OF CO2 FIXATIION IN OCEANIC RIVER PLUMES Oceanic river plumes represent some of the most productive environments on Earth. As major conduits for freshwater and nutrients into the coastal ocean, their impact on water column ecosystems extend for up

  6. FINAL TECHNICAL REPORT-THE ECOLOGY AND GENOMICS OF CO2 FIXATIION IN OCEANIC

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

    RIVER PLUMES (Technical Report) | SciTech Connect Technical Report: FINAL TECHNICAL REPORT-THE ECOLOGY AND GENOMICS OF CO2 FIXATIION IN OCEANIC RIVER PLUMES Citation Details In-Document Search Title: FINAL TECHNICAL REPORT-THE ECOLOGY AND GENOMICS OF CO2 FIXATIION IN OCEANIC RIVER PLUMES Oceanic river plumes represent some of the most productive environments on Earth. As major conduits for freshwater and nutrients into the coastal ocean, their impact on water column ecosystems extend for up

  7. CX-007901: Categorical Exclusion Determination

    Broader source: Energy.gov [DOE]

    Improving Atmospheric Models for Offshore Wind Resource Mapping and Prediction Using LIDAR, Aircraft, and In-Ocean Observations CX(s) Applied: A9, A11, B3.1, B3.2 Date: 02/22/2012 Location(s): New York Offices(s): Golden Field Office

  8. CX-009575: Categorical Exclusion Determination

    Broader source: Energy.gov [DOE]

    Improving Atmospheric Models for Offshore Wind Resource Mapping and Prediction Using LIDAR, Aircraft and In-Ocean Observations CX(s) Applied: A9, B3.1, B3.2 Date: 12/12/2012 Location(s): New York Offices(s): Golden Field Office

  9. An assessment of research and development leadership in ocean energy technologies

    SciTech Connect (OSTI)

    Bruch, V.L.

    1994-04-01

    Japan is clearly the leader in ocean energy technologies. The United Kingdom also has had many ocean energy research projects, but unlike Japan, most of the British projects have not progressed from the feasibility study stage to the demonstration stage. Federally funded ocean energy research in the US was stopped because it was perceived the technologies could not compete with conventional sources of fuel. Despite the probable small market for ocean energy technologies, the short sighted viewpoint of the US government regarding funding of these technologies may be harmful to US economic competitiveness. The technologies may have important uses in other applications, such as offshore construction and oil and gas drilling. Discontinuing the research and development of these technologies may cause the US to lose knowledge and miss market opportunities. If the US wishes to maintain its knowledge base and a market presence for ocean energy technologies, it may wish to consider entering into a cooperative agreement with Japan and/or the United Kingdom. Cooperative agreements are beneficial not only for technology transfer but also for cost-sharing.

  10. Method and apparatus for efficient injection of CO2 in oceans

    DOE Patents [OSTI]

    West, Olivia R.; Tsouris, Constantinos; Liang, Liyuan

    2003-07-29

    A liquid CO.sub.2 injection system produces a negatively buoyant consolidated stream of liquid CO.sub.2, CO.sub.2 hydrate, and water that sinks upon release at ocean depths in the range of 700-1500 m. In this approach, seawater at a predetermined ocean depth is mixed with the liquid CO.sub.2 stream before release into the ocean. Because mixing is conducted at depths where pressures and temperatures are suitable for CO.sub.2 hydrate formation, the consolidated stream issuing from the injector is negatively buoyant, and comprises mixed CO.sub.2 -hydrate/CO.sub.2 -liquid/water phases. The "sinking" characteristic of the produced stream will prolong the metastability of CO.sub.2 ocean sequestration by reducing the CO.sub.2 dissolution rate into water. Furthermore, the deeper the CO.sub.2 hydrate stream sinks after injection, the more stable it becomes internally, the deeper it is dissolved, and the more dispersed is the resulting CO.sub.2 plume. These factors increase efficiency, increase the residence time of CO2 in the ocean, and decrease the cost of CO.sub.2 sequestration while reducing deleterious impacts of free CO.sub.2 gas in ocean water.

  11. Mechanisms Leading to Co-Existence of Gas Hydrate in Ocean Sediments [Part 2 of 2

    SciTech Connect (OSTI)

    Bryant, Steven; Juanes, Ruben

    2011-12-31

    In this project we have sought to explain the co-existence of gas and hydrate phases in sediments within the gas hydrate stability zone. We have focused on the gas/brine interface at the scale of individual grains in the sediment. The capillary forces associated with a gas/brine interface play a dominant role in many processes that occur in the pores of sediments and sedimentary rocks. The mechanical forces associated with the same interface can lead to fracture initiation and propagation in hydrate-bearing sediments. Thus the unifying theme of the research reported here is that pore scale phenomena are key to understanding large scale phenomena in hydrate-bearing sediments whenever a free gas phase is present. Our analysis of pore-scale phenomena in this project has delineated three regimes that govern processes in which the gas phase pressure is increasing: fracturing, capillary fingering and viscous fingering. These regimes are characterized by different morphology of the region invaded by the gas. On the other hand when the gas phase pressure is decreasing, the corresponding regimes are capillary fingering and compaction. In this project, we studied all these regimes except compaction. Many processes of interest in hydrate-bearing sediments can be better understood when placed in the context of the appropriate regime. For example, hydrate formation in sub-permafrost sediments falls in the capillary fingering regime, whereas gas invasion into ocean sediments is likely to fall into the fracturing regime. Our research provides insight into the mechanisms by which gas reservoirs are converted to hydrate as the base of the gas hydrate stability zone descends through the reservoir. If the reservoir was no longer being charged, then variation in grain size distribution within the reservoir explain hydrate saturation profiles such as that at Mt. Elbert, where sand-rich intervals containing little hydrate are interspersed between intervals containing large hydrate saturations. Large volumes (of order one pore volume) of gaseous and aqueous phases must be transported into the gas hydrate stability zone. The driver for this transport is the pressure sink induced by a reduction in occupied pore volume that accompanies the formation of hydrate from gas and water. Pore-scale imbibition models and bed-scale multiphase flow models indicate that the rate-limiting step in converting gas to hydrate is the supply of water to the hydrate stability zone. Moreover, the water supply rate is controlled by capillarity-driven flux for conditions typical of the Alaska North Slope. A meter-scale laboratory experiment confirms that significant volumes of fluid phases move into the hydrate stability zone and that capillarity is essential for the water flux. The model shows that without capillarity-driven flux, large saturations of hydrate cannot form. The observations of thick zones of large saturation at Mallik and Mt Elbert thus suggest that the primary control on these systems is the rate of transport of gaseous and aqueous phases, driven by the pressure sink at the base of the gas hydrate stability zone. A key finding of our project is the elucidation of ?capillary fracturing? as a dominant gas transport mechanism in low-permeability media. We initially investigate this phenomenon by means of grain-scale simulations in which we extended a discrete element mechanics code (PFC, by Itasca) to incorporate the dynamics of first singlephase and then multiphase flow. A reductionist model on a square lattice allows us to determine some of the fundamental dependencies of the mode of gas invasion (capillary fingering, viscous fingering, and fracturing) on the parameters of the system. We then show that the morphology of the gas-invaded region exerts a fundamental control on the fabric of methane hydrate formation, and on the overpressures caused by methane hydrate dissociation. We demonstrate the existence of the different invasion regimes by means of controlled laboratory experiments in a radial cell. We collapse the behavior in the form of a phase dia

  12. Mechanisms Leading to Co-Existence of Gas Hydrate in Ocean Sediments [Part 1 of 2

    SciTech Connect (OSTI)

    Bryant, Steven; Juanes, Ruben

    2011-12-31

    In this project we have sought to explain the co-existence of gas and hydrate phases in sediments within the gas hydrate stability zone. We have focused on the gas/brine interface at the scale of individual grains in the sediment. The capillary forces associated with a gas/brine interface play a dominant role in many processes that occur in the pores of sediments and sedimentary rocks. The mechanical forces associated with the same interface can lead to fracture initiation and propagation in hydrate-bearing sediments. Thus the unifying theme of the research reported here is that pore scale phenomena are key to understanding large scale phenomena in hydrate-bearing sediments whenever a free gas phase is present. Our analysis of pore-scale phenomena in this project has delineated three regimes that govern processes in which the gas phase pressure is increasing: fracturing, capillary fingering and viscous fingering. These regimes are characterized by different morphology of the region invaded by the gas. On the other hand when the gas phase pressure is decreasing, the corresponding regimes are capillary fingering and compaction. In this project, we studied all these regimes except compaction. Many processes of interest in hydrate-bearing sediments can be better understood when placed in the context of the appropriate regime. For example, hydrate formation in sub-permafrost sediments falls in the capillary fingering regime, whereas gas invasion into ocean sediments is likely to fall into the fracturing regime. Our research provides insight into the mechanisms by which gas reservoirs are converted to hydrate as the base of the gas hydrate stability zone descends through the reservoir. If the reservoir was no longer being charged, then variation in grain size distribution within the reservoir explain hydrate saturation profiles such as that at Mt. Elbert, where sand-rich intervals containing little hydrate are interspersed between intervals containing large hydrate saturations. Large volumes (of order one pore volume) of gaseous and aqueous phases must be transported into the gas hydrate stability zone. The driver for this transport is the pressure sink induced by a reduction in occupied pore volume that accompanies the formation of hydrate from gas and water. Pore-scale imbibition models and bed-scale multiphase flow models indicate that the rate-limiting step in converting gas to hydrate is the supply of water to the hydrate stability zone. Moreover, the water supply rate is controlled by capillarity-driven flux for conditions typical of the Alaska North Slope. A meter-scale laboratory experiment confirms that significant volumes of fluid phases move into the hydrate stability zone and that capillarity is essential for the water flux. The model shows that without capillarity-driven flux, large saturations of hydrate cannot form. The observations of thick zones of large saturation at Mallik and Mt Elbert thus suggest that the primary control on these systems is the rate of transport of gaseous and aqueous phases, driven by the pressure sink at the base of the gas hydrate stability zone. A key finding of our project is the elucidation of ?capillary fracturing? as a dominant gas transport mechanism in low-permeability media. We initially investigate this phenomenon by means of grain-scale simulations in which we extended a discrete element mechanics code (PFC, by Itasca) to incorporate the dynamics of first single-phase and then multiphase flow. A reductionist model on a square lattice allows us to determine some of the fundamental dependencies of the mode of gas invasion (capillary fingering, viscous fingering, and fracturing) on the parameters of the system. We then show that the morphology of the gas-invaded region exerts a fundamental control on the fabric of methane hydrate formation, and on the overpressures caused by methane hydrate dissociation. We demonstrate the existence of the different invasion regimes by means of controlled laboratory experiments in a radial cell. We collapse the behavior in the form of a phase di

  13. Geo-neutrino Observation

    SciTech Connect (OSTI)

    Dye, S. T.; Alderman, M.; Batygov, M.; Learned, J. G.; Matsuno, S.; Mahoney, J. M.; Pakvasa, S.; Rosen, M.; Smith, S.; Varner, G.; McDonough, W. F.

    2009-12-17

    Observations of geo-neutrinos measure radiogenic heat production within the earth, providing information on the thermal history and dynamic processes of the mantle. Two detectors currently observe geo-neutrinos from underground locations. Other detection projects in various stages of development include a deep ocean observatory. This paper presents the current status of geo-neutrino observation and describes the scientific capabilities of the deep ocean observatory, with emphasis on geology and neutrino physics.

  14. Hot Pot Field Observations

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

    Lane, Michael

    2013-06-28

    Map of field observations including depressions, springs, evidence of former springs, travertine terraces and vegetation patterns. Map also contains interpretation of possible spring alignments.

  15. Hot Pot Field Observations

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

    Lane, Michael

    Map of field observations including depressions, springs, evidence of former springs, travertine terraces and vegetation patterns. Map also contains interpretation of possible spring alignments.

  16. Safety Observations Achieve Results

    Energy Science and Technology Software Center (OSTI)

    2000-01-16

    The SOAR web application provides a multi-checklist capability where focused observations can be created to address risk-likely work environments, tasks, etc. The SOAR web application has numerous reports to sort the data by key word, multiple factors (i.e., location, team, behavior, checklist, work environment, etc.), and the highest frequency of behaviors and error-likely predecessors, etc. Other performance indicators are also provided.

  17. Earth System Observations

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

    4 Earth System Observations Research comprises Earth, ocean, and atmospheric sciences to better understand and predict climate change's impact on ecosystems and to study subsurface geological materials and their interactions. Deploying research facilities globally Forecasting forests' responses to climate change Monitoring terrestrial ecosystems Contact Us Group Leader (acting) Bob Roback Email Deputy Group Leader (acting) Jeff Heikoop Email Profile pages header Search our Profile pages

  18. Observations

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

    sulla Fusione, Corso Stati Uniti, 4 35127 Padova, Italy * 2 Istituto Nazionale di Fisica della Materia, UdR Padova, Italy 3 Department of Physics, University of ...

  19. Observation

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

    P. Martin Consorzio RFX, Associazione EURATOM-ENEA sulla Fusione, Corso Stati Uniti 4, 35127 Padova, Italy and Istituto Nazionale Fisica della Materia, INFM, Padova, Italy G. ...

  20. Observation

    Office of Scientific and Technical Information (OSTI)

    to an Orbital-Selective Mott Phase in A x Fe 2-y Se 2 (AK, Rb) Superconductors M. Yi, 1, 2 D. H. Lu, 3 R. Yu, 4 S. C. Riggs, 1, 2 J.-H. Chu, 1, 2 B. Lv, 5 Z. Liu, 1, 2 M. Lu,...

  1. Field observations and lessons learned

    SciTech Connect (OSTI)

    Nielsen, Joh B

    2010-01-01

    This presentation outlines observations and lessons learned from the Megaports program. It provides: (1) details of field and technical observations collected during LANL field activities at ports around the world and details of observations collected during radiation detections system testing at Los Alamos National Laboratory; (2) provides suggestions for improvement and efficiency; and (3) discusses possible program execution changes for more effective operations.

  2. State observer for synchronous motors

    DOE Patents [OSTI]

    Lang, Jeffrey H. (Waltham, MA)

    1994-03-22

    A state observer driven by measurements of phase voltages and currents for estimating the angular orientation of a rotor of a synchronous motor such as a variable reluctance motor (VRM). Phase voltages and currents are detected and serve as inputs to a state observer. The state observer includes a mathematical model of the electromechanical operation of the synchronous motor. The characteristics of the state observer are selected so that the observer estimates converge to the actual rotor angular orientation and velocity, winding phase flux linkages or currents.

  3. NS&T MANAGEMENT OBSERVATIONS

    SciTech Connect (OSTI)

    Gianotto, David

    2014-06-01

    The INL Management Observation Program (MOP) is designed to improve managers and supervisors understanding of work being performed by employees and the barriers impacting their success. The MOP also increases workers understanding of managements expectations as they relate to safety, security, quality, and work performance. Management observations (observations) are designed to improve the relationship and trust between employees and managers through increased engagement and interactions between managers and researchers in the field. As part of continuous improvement, NS&T management took initiative to focus on the participation and quality of observations in FY 14. This quarterly report is intended to (a) summarize the participation and quality of managements observations, (b) assess observations for commonalities or trends related to facility or process barriers impacting research, and (c) provide feedback and make recommendations for improvements NS&Ts MOP.

  4. NS&T Management Observations

    SciTech Connect (OSTI)

    Gianotto, David

    2014-09-01

    The INL Management Observation Program (MOP) is designed to improve managers and supervisors understanding of work being performed by employees and the barriers impacting their success. The MOP also increases workers understanding of managements expectations as they relate to safety, security, quality, and work performance. Management observations (observations) are designed to improve the relationship and trust between employees and managers through increased engagement and interactions between managers and researchers in the field. As part of continuous improvement, NS&T management took initiative to focus on the participation and quality of observations in FY 14. This quarterly report is intended to (a) summarize the participation and quality of managements observations, (b) assess observations for commonalities or trends related to facility or process barriers impacting research, and (c) provide feedback and make recommendations for improvements NS&Ts MOP.

  5. ARM - Surface Aerosol Observing System

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

    2009-2010 Shouxian, China, 2008 Black Forest, Germany, 2007 Niamey, Niger, 2006 Point Reyes, California, 2005 Surface Aerosol Observing System The ARM Mobile Facility (AMF) is...

  6. Distant Observer - Energy Innovation Portal

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

    Solar Thermal Solar Thermal Energy Analysis Energy Analysis Find More Like This Return to Search Distant Observer Tool Quickly Identifies Costly Flaws in Concentrating Solar Power (CSP) Fields National Renewable Energy Laboratory Contact NREL About This Technology Technology Marketing Summary As we pursue efforts to lower the capital and installation costs of parabolic trough solar collectors, it is essential to maintain high optical performance. The Distant Observer (DO) tool, developed by

  7. Biomass Burning Observation Project Specifically,

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

    Burning Observation Project Specifically, the aircraft will obtain measurements of the microphysical, chemical, hygroscopic, and optical properties of aerosols. Data captured during BBOP will help scientists better understand how aerosols combine and change at a variety of distances and burn times. Locations Pasco, Washington. From July through September, the G-1 will be based out of its home base in Washington. From this location, it can intercept and measure smoke plumes from naturally

  8. Diffuse Shortwave Intensive Observation Period

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

    1 Diffuse Shortwave Intensive Observation Period The Diffuse Shortwave IOP ran from September 23 to October 12, 2001. During this IOP, Joe Michalsky (The State University of New York-Albany) and Tom Stoffel (National Renewable Energy Laboratory) deployed approximately 15 radiometers of various designs and manufacturers on the SGP Radiometer Calibration Facility. The purpose was to compare the accuracy of the radiometers for diffuse shortwave measurements. The Scripps Institution of Oceanography

  9. Intensive Observation Period Projects Scheduled

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

    1 Intensive Observation Period Projects Scheduled Several IOP projects have been scheduled for the SGP CART site this spring. These projects either have already begun or will begin shortly. Radiosondes The RS-90 Transition IOP is currently under way. The RS-90 model radiosonde is gradually replacing the older RS-80 model. Radiosondes are instrument packages attached to and launched by weather balloons. The instruments measure atmospheric pressure, temperature, and relative humidity as the

  10. ARM - Mobile Aerosol Observing System

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

    FacilitiesMobile Aerosol Observing System AMF Information Science Architecture Baseline Instruments AMF1 AMF2 AMF3 MAOS Data Operations AMF Fact Sheet Images Contacts AMF Deployments McMurdo Station, Antarctica, 2015-2016 Pearl Harbor, Hawaii, to San Francisco, California, 2015 Hyytiälä, Finland, 2014 Manacapuru, Brazil, 2014 Oliktok Point, Alaska, 2013 Los Angeles, California, to Honolulu, Hawaii, 2012 Cape Cod, Massachusetts, 2012 Gan Island, Maldives, 2011 Ganges Valley, India, 2011

  11. Observation of Nonlinear Compton Scattering

    SciTech Connect (OSTI)

    Kotseroglou, T.

    2003-12-19

    This experiment tests Quantum Electrodynamics in the strong field regime. Nonlinear Compton scattering has been observed during the interaction of a 46.6 GeV electron beam with a 10{sup 18} W/cm{sup 2} laser beam. The strength of the field achieved was measured by the parameter {eta} = e{var_epsilon}{sub rms}/{omega}mc = 0.6. Data were collected with infrared and green laser photons and circularly polarized laser light. The timing stabilization achieved between the picosecond laser and electron pulses has {sigma}{sub rms} = 2 ps. A strong signal of electrons that absorbed up to 4 infrared photons (or up to 3 green photons) at the same point in space and time, while emitting a single gamma ray, was observed. The energy spectra of the scattered electrons and the nonlinear dependence of the electron yield on the field strength agreed with the simulation over 3 orders of magnitude. The detector could not resolve the nonlinear Compton scattering from the multiple single Compton scattering which produced rates of scattered electrons of the same order of magnitude. Nevertheless, a simulation has studied this difference and concluded that the scattered electron rates observed could not be accounted for only by multiple ordinary Compton scattering; nonlinear Compton scattering processes are dominant for n {ge} 3.

  12. Category:Observation Wells | Open Energy Information

    Open Energy Info (EERE)

    Observation Wells Jump to: navigation, search Geothermalpower.jpg Looking for the Observation Wells page? For detailed information on Observation Wells, click here....

  13. Observation of the Top Quark

    DOE R&D Accomplishments [OSTI]

    Kim, S. B.

    1995-08-01

    Top quark production is observed in{bar p}p collisions at{radical}s= 1.8 TeV at the Fermilab Tevatron. The Collider Detector at Fermilab (CDF) and D{O} observe signals consistent with t{bar t} to WWb{bar b}, but inconsistent with the background prediction by 4.8{sigma} (CDF), 4.6a (D{O}). Additional evidence for the top quark Is provided by a peak in the reconstructed mass distribution. The kinematic properties of the excess events are consistent with the top quark decay. They measure the top quark mass to be 176{plus_minus}8(stat.){plus_minus}10(sys.) GeV/c{sup 2} (CDF), 199{sub -21}{sup+19}(stat.){plus_minus}22(sys.) GeV/c{sup 2} (D{O}), and the t{bar t} production cross section to be 6.8{sub -2.4}{sup+3.6}pb (CDF), 6.4{plus_minus}2.2 pb (D{O}).

  14. Aerosol Observing System (AOS) Handbook

    SciTech Connect (OSTI)

    Jefferson, A

    2011-01-17

    The Aerosol Observing System (AOS) is a suite of in situ surface measurements of aerosol optical and cloud-forming properties. The instruments measure aerosol properties that influence the earths radiative balance. The primary optical measurements are those of the aerosol scattering and absorption coefficients as a function of particle size and radiation wavelength and cloud condensation nuclei (CCN) measurements as a function of percent supersaturation. Additional measurements include those of the particle number concentration and scattering hygroscopic growth. Aerosol optical measurements are useful for calculating parameters used in radiative forcing calculations such as the aerosol single-scattering albedo, asymmetry parameter, mass scattering efficiency, and hygroscopic growth. CCN measurements are important in cloud microphysical models to predict droplet formation.

  15. Comet tail formation: Giotto observations

    SciTech Connect (OSTI)

    Wilken, B.; Jockers, K.; Johnstone, A.; Coates, A.; Heath, J.; Formisano, V.; Amata, E.; Winningham, J.D.; Thomsen, M.; Bryant, D.A.

    1986-01-01

    The process of mass loading of the solar wind by cometary ions, which forms comet tails, has been observed throughout the coma of comet Halley. Three distinct regimes were found where the nature of the energy and momentum coupling between solar wind and cometary ions is different. Outside the bow shock, where there is little angular scattering of the freshly ionized particles, the coupling is described by the simple pickup trajectory and the energy is controlled by the angle between the flow and the magnetic field. Just inside the bow shock, there is considerable scattering accompanied by another acceleration process which raises some particle energies well above the straightforward pickup value. Finally, closer to the nucleus, the amount of scattering decreases and the coupling is once more controlled by the magnetic field direction. 4 refs., 3 figs.

  16. New photodisintegration threshold observable in

    SciTech Connect (OSTI)

    E.A. Wulf; R.S. Canon; Sally J. Gaff; J.H. Kelley; R.M. Prior; E.C. Schreiber; M. Spraker; D.R. Tilley; H.R. Weller; M. Viviani; A. Kievsky; S. Rosati; Rocco Schiavilla

    2000-02-01

    Measurements of the cross section, vector, and tensor analyzing powers, and linear gamma-ray polarization in the radiative capture reactions D(p,y){sup 3} He and p(d,y){sup 3}He at c.m. energies in the range 0-53 keV allow the determination of the reduced matrix elements (RMEs) relevant for these transitions. From these RMEs the value of the integral which determines the Gerasimov-Drell-Hearn sum rule for He is obtained in the threshold region, corresponding to two-body breakup, and compared with the results of an ab initio microscopic three-body model calculation.The theoretical predictions for the value of this integral based on a ''nucleons-only'' assumption are an order of magnitude smaller than experiment. The discrepancy is reduced to about a factor of 2 when two-body currents are taken into account. This factor of 2 is due to an almost exact cancellation between the dominant E1 RMEs in the theoretical calculation. The excess E1 strength observed experimentally could provide useful insights into the nuclear interaction at low energies.

  17. GNEP Partners and Observers | Department of Energy

    Office of Environmental Management (EM)

    GNEP Partners and Observers GNEP Partners and Observers A list of GNEP partners and observers. PDF icon GNEP Partners and Observers More Documents & Publications Microsoft PowerPoint - GNEP PARTNERS CANDIDATE PARTNERS AND OBSERVERS.PPT Senior Delegation Officials From All GNEP Participants Meeting Materials: April 21, 2008

  18. Special Emphasis Observances | Department of Energy

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

    Diversity and Inclusion » Special Emphasis Observances Special Emphasis Observances The Energy Department celebrates special emphasis observances regularly, inviting guest speakers to highlight how the agency's mission benefits from diversity and inclusion. The Energy Department celebrates special emphasis observances regularly, inviting guest speakers to highlight how the agency's mission benefits from diversity and inclusion. The Department of Energy observes special days, weeks, and months

  19. First Observation of Plasmarons in Graphene

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

    First Observation of Plasmarons in Graphene First Observation of Plasmarons in Graphene Print Wednesday, 30 June 2010 00:00 An international team of scientists performing...

  20. Dynamics of Molecular Clouds: Observations, Simulations, and...

    Office of Scientific and Technical Information (OSTI)

    Conference: Dynamics of Molecular Clouds: Observations, Simulations, and NIF Experiments Citation Details In-Document Search Title: Dynamics of Molecular Clouds: Observations,...

  1. First Observation of Plasmarons in Graphene

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

    First Observation of Plasmarons in Graphene Print An international team of scientists performing angle-resolved photoemission spectroscopy (ARPES) experiments at ALS Beamline 7.0.1...

  2. Enterprise Assessments Operational Awareness Record of Observations...

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

    Site: Waste Isolation Pilot Plant (WIPP) Subject: Observations of the design and modification progress of ... with regards to the design process and not to any state or local ...

  3. Posters Ground-Based Radiometric Observations

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

    data have also complemented other remote sensors such as K-band cloud Doppler radar and Doppler lidar. In addition, radiometric observations compose a database of ground- truth...

  4. Radioactivity in Precipitation: Methods and Observations from...

    Office of Environmental Management (EM)

    Radioactivity in Precipitation: Methods & Observations from Savannah River Site Dennis Jackson P.E. & Timothy Jannik - Savannah River National Laboratory Teresa Eddy - Savannah...

  5. Report: Human Capital Discussion and Observations

    Office of Environmental Management (EM)

    Human Capital Discussion, Observations, and Recommendations August 24, 2006 Submitted by: Mr. A. James Barnes and Mr. Dennis Ferrigno Background: During the March 23-24, 2006 EMAB...

  6. EA-1964: National Ecological Observation Network (NEON)

    Broader source: Energy.gov [DOE]

    The National Science Foundation (NSF) prepared an EA that evaluated potential environmental impacts of the proposed National Ecological Observation Network (NEON), a continental-scale network of...

  7. Aircraft S-HIS Observations during MPACE

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

    Aircraft S-HIS Observations during MPACE DeSlover, Daniel University of Wisconsin Holz, Robert University of Wisconsin, CIMMS Turner, David University of Wisconsin-Madison...

  8. Dynamics of Molecular Clouds: Observations, Simulations, and...

    Office of Scientific and Technical Information (OSTI)

    Simulations, and NIF Experiments Citation Details In-Document Search Title: Dynamics of Molecular Clouds: Observations, Simulations, and NIF Experiments Authors: Kane, J ...

  9. First Direct Observation of Spinons and Holons

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

    check on the interpretation of the data-were not available. The current observations are direct and the results are unambiguous because they were obtained from a simple material...

  10. ARM - Field Campaign - Biomass Burning Observation Project -...

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

    govCampaignsBiomass Burning Observation Project - BBOP Campaign Links BBOP Website ARM Data Discovery Browse Data Comments? We would love to hear from you Send us a note below or...

  11. First Direct Observation of Spinons and Holons

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

    structure has remained elusive. Working at the ALS, a team of researchers from Korea, Japan, and the U.S. has now observed electron spin-charge separation in a one-dimensional...

  12. Observations and simulations improve space weather models

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

    Observations improve space weather models Observations and simulations improve space weather models Researchers used data from the Van Allen Probes to improve a three-dimensional model created by Los Alamos scientists called DREAM3D. June 25, 2014 NASA's Van Allen Probes sample the Earth's magnetosphere. NASA's Van Allen Probes sample the Earth's magnetosphere. The work demonstrated that DREAM3D accurately simulated the behavior of a complex and dynamic event in the radiation belt that was

  13. Observing AAPI Heritage Month | Department of Energy

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

    Observing AAPI Heritage Month Observing AAPI Heritage Month May 1, 2012 - 4:42pm Addthis Bill Valdez Bill Valdez Director of Workforce Management What are the key facts? President Obama has also appointed a historic number of highly qualified Asian Americans and Pacific Islanders to senior positions in his Administration Throughout May,the White House Initiative on Asian Americans and Pacific Islanders will be sharing the many ways in which the Obama Administration has helped the Asian American

  14. Observations and simulations improve space weather models

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

    Observations improve space weather models Observations and simulations improve space weather models Researchers used data from the Van Allen Probes to improve a three-dimensional model created by Los Alamos scientists called DREAM3D. June 25, 2014 NASA's Van Allen Probes sample the Earth's magnetosphere. NASA's Van Allen Probes sample the Earth's magnetosphere. The work demonstrated that DREAM3D accurately simulated the behavior of a complex and dynamic event in the radiation belt that was

  15. First Direct Observation of Spinons and Holons

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

    First Direct Observation of Spinons and Holons First Direct Observation of Spinons and Holons Print Wednesday, 30 August 2006 00:00 Spin and charge are inseparable traits of an electron, but in one-dimensional solids, a 40-year-old theory predicts their separation into "collective" modes-as independent excitation quanta called spinons and holons. Angle-resolved photoemission spectroscopy (ARPES) should provide the most direct evidence of this spin-charge separation, as the single

  16. First Observation of Plasmarons in Graphene

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

    First Observation of Plasmarons in Graphene First Observation of Plasmarons in Graphene Print Wednesday, 30 June 2010 00:00 An international team of scientists performing angle-resolved photoemission spectroscopy (ARPES) experiments at ALS Beamline 7.0.1 have found that composite particles called plasmarons play a vital role in determining graphene's properties. A plasmaron consists of a charge carrier (electron or hole) coupled with a plasmon-an electron density wave. Although plasmarons were

  17. Correlation between human observer performance and model observer performance in differential phase contrast CT

    SciTech Connect (OSTI)

    Li, Ke; Garrett, John; Chen, Guang-Hong

    2013-11-15

    Purpose: With the recently expanding interest and developments in x-ray differential phase contrast CT (DPC-CT), the evaluation of its task-specific detection performance and comparison with the corresponding absorption CT under a given radiation dose constraint become increasingly important. Mathematical model observers are often used to quantify the performance of imaging systems, but their correlations with actual human observers need to be confirmed for each new imaging method. This work is an investigation of the effects of stochastic DPC-CT noise on the correlation of detection performance between model and human observers with signal-known-exactly (SKE) detection tasks.Methods: The detectabilities of different objects (five disks with different diameters and two breast lesion masses) embedded in an experimental DPC-CT noise background were assessed using both model and human observers. The detectability of the disk and lesion signals was then measured using five types of model observers including the prewhitening ideal observer, the nonprewhitening (NPW) observer, the nonprewhitening observer with eye filter and internal noise (NPWEi), the prewhitening observer with eye filter and internal noise (PWEi), and the channelized Hotelling observer (CHO). The same objects were also evaluated by four human observers using the two-alternative forced choice method. The results from the model observer experiment were quantitatively compared to the human observer results to assess the correlation between the two techniques.Results: The contrast-to-detail (CD) curve generated by the human observers for the disk-detection experiments shows that the required contrast to detect a disk is inversely proportional to the square root of the disk size. Based on the CD curves, the ideal and NPW observers tend to systematically overestimate the performance of the human observers. The NPWEi and PWEi observers did not predict human performance well either, as the slopes of their CD curves tended to be steeper. The CHO generated the best quantitative agreement with human observers with its CD curve overlapping with that of human observer. Statistical equivalence between CHO and humans can be claimed within 11% of the human observer results, including both the disk and lesion detection experiments.Conclusions: The model observer method can be used to accurately represent human observer performance with the stochastic DPC-CT noise for SKE tasks with sizes ranging from 8 to 128 pixels. The incorporation of the anatomical noise remains to be studied.

  18. Selecting Observation Platforms for Optimized Anomaly Detectability under Unreliable Partial Observations

    SciTech Connect (OSTI)

    Wen-Chiao Lin; Humberto E. Garcia; Tae-Sic Yoo

    2011-06-01

    Diagnosers for keeping track on the occurrences of special events in the framework of unreliable partially observed discrete-event dynamical systems were developed in previous work. This paper considers observation platforms consisting of sensors that provide partial and unreliable observations and of diagnosers that analyze them. Diagnosers in observation platforms typically perform better as sensors providing the observations become more costly or increase in number. This paper proposes a methodology for finding an observation platform that achieves an optimal balance between cost and performance, while satisfying given observability requirements and constraints. Since this problem is generally computational hard in the framework considered, an observation platform optimization algorithm is utilized that uses two greedy heuristics, one myopic and another based on projected performances. These heuristics are sequentially executed in order to find best observation platforms. The developed algorithm is then applied to an observation platform optimization problem for a multi-unit-operation system. Results show that improved observation platforms can be found that may significantly reduce the observation platform cost but still yield acceptable performance for correctly inferring the occurrences of special events.

  19. Singular behavior of jet substructure observables

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

    Larkoski, Andrew J.; Moult, Ian

    2016-01-20

    Jet substructure observables play a central role at the Large Hadron Collider for identifying the boosted hadronic decay products of electroweak scale resonances. The complete description of these observables requires understanding both the limit in which hard substructure is resolved, as well as the limit of a jet with a single hard core. In this paper we study in detail the perturbative structure of two prominent jet substructure observables, N-subjettiness and the energy correlation functions, as measured on background QCD jets. In particular, we focus on the distinction between the limits in which two-prong structure is resolved or unresolved. Dependingmore » on the choice of subjet axes, we demonstrate that at fixed order, N-subjettiness can manifest myriad behaviors in the unresolved region: smooth tails, end-point singularities, or singularities in the physical region. The energy correlation functions, by contrast, only have non-singular perturbative tails extending to the end point. We discuss the effect of hadronization on the various observables with Monte Carlo simulation and demonstrate that the modeling of these effects with non-perturbative shape functions is highly dependent on the N-subjettiness axes definitions. Lastly, our study illustrates those regions of phase space that must be controlled for high-precision jet substructure calculations, and emphasizes how such calculations can be facilitated by designing substructure observables with simple singular structures.« less

  20. OBSERVING CORONAL NANOFLARES IN ACTIVE REGION MOSS

    SciTech Connect (OSTI)

    Testa, Paola; DeLuca, Ed; Golub, Leon; Korreck, Kelly; Weber, Mark; De Pontieu, Bart; Martinez-Sykora, Juan; Title, Alan; Hansteen, Viggo; Cirtain, Jonathan; Winebarger, Amy; Kobayashi, Ken; Kuzin, Sergey; Walsh, Robert; DeForest, Craig

    2013-06-10

    The High-resolution Coronal Imager (Hi-C) has provided Fe XII 193A images of the upper transition region moss at an unprecedented spatial ({approx}0.''3-0.''4) and temporal (5.5 s) resolution. The Hi-C observations show in some moss regions variability on timescales down to {approx}15 s, significantly shorter than the minute-scale variability typically found in previous observations of moss, therefore challenging the conclusion of moss being heated in a mostly steady manner. These rapid variability moss regions are located at the footpoints of bright hot coronal loops observed by the Solar Dynamics Observatory/Atmospheric Imaging Assembly in the 94 A channel, and by the Hinode/X-Ray Telescope. The configuration of these loops is highly dynamic, and suggestive of slipping reconnection. We interpret these events as signatures of heating events associated with reconnection occurring in the overlying hot coronal loops, i.e., coronal nanoflares. We estimate the order of magnitude of the energy in these events to be of at least a few 10{sup 23} erg, also supporting the nanoflare scenario. These Hi-C observations suggest that future observations at comparable high spatial and temporal resolution, with more extensive temperature coverage, are required to determine the exact characteristics of the heating mechanism(s).

  1. Testing the copernican principle via cosmological observations

    SciTech Connect (OSTI)

    Bolejko, Krzysztof; Wyithe, J. Stuart B. E-mail: swyithe@unimelb.edu.au

    2009-02-15

    Observations of distances to Type-Ia supernovae can be explained by cosmological models that include either a gigaparsec-scale void, or a cosmic flow, without the need for Dark Energy. Instead of invoking dark energy, these inhomogeneous models instead violate the Copernican Principle. we show that current cosmological observations (Supernovae, Baryon Acoustic Oscillations and estimates of the Hubble parameters based on the age of the oldest stars) are not able to rule out inhomogeneous anti-Copernican models. The next generation of surveys for baryonic acoustic oscillations will be sufficiently precise to either validate the Copernican Principle or determine the existence of a local Gpc scale inhomogeneity.

  2. ARM - PI Product - Niamey Dust Observations

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

    Dust Observations ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send PI Product : Niamey Dust Observations Niamey aerosol are composed of two main components: dust due to the proximity of the Sahara Desert, and soot from local and regional biomass burning. The purpose of this data product is to identify when the local conditions are dominated by the dust component so that the properties of the dust events can be

  3. Observational constraints on Tachyon and DBI inflation

    SciTech Connect (OSTI)

    Li, Sheng; Liddle, Andrew R. E-mail: arl@roe.ac.uk

    2014-03-01

    We present a systematic method for evaluation of perturbation observables in non-canonical single-field inflation models within the slow-roll approximation, which allied with field redefinitions enables predictions to be established for a wide range of models. We use this to investigate various non-canonical inflation models, including Tachyon inflation and DBI inflation. The Lambert W function will be used extensively in our method for the evaluation of observables. In the Tachyon case, in the slow-roll approximation the model can be approximated by a canonical field with a redefined potential, which yields predictions in better agreement with observations than the canonical equivalents. For DBI inflation models we consider contributions from both the scalar potential and the warp geometry. In the case of a quartic potential, we find a formula for the observables under both non-relativistic (sound speed c{sub s}{sup 2}?1) and relativistic behaviour (c{sub s}{sup 2}||1) of the scalar DBI inflaton. For a quadratic potential we find two branches in the non-relativistic c{sub s}{sup 2}?1 case, determined by the competition of model parameters, while for the relativistic case c{sub s}{sup 2}?0, we find consistency with results already in the literature. We present a comparison to the latest Planck satellite observations. Most of the non-canonical models we investigate, including the Tachyon, are better fits to data than canonical models with the same potential, but we find that DBI models in the slow-roll regime have difficulty in matching the data.

  4. First direct observation of muon antineutrino disappearance

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

    Adamson, P.

    2011-07-05

    This letter reports the first direct observation of muon antineutrino disappearance. The MINOS experiment has taken data with an accelerator beam optimized for ν̄μ production, accumulating an exposure of 1.71 x 1020 protons on target. In the Far Detector, 97 charged current ν̄μ events are observed. The no-oscillation hypothesis predicts 156 events and is excluded at 6.3σ. The best fit to oscillation yields |Δm̄2| = (3.36-0.40 +0.46(stat.) ± 0.06(syst.)) x 10-3 eV2, sin2(2 θ̄) = 0.86-0.12+0.11 (stat.) ± 0.01(syst.). The MINOS νμ and ν̄μ measurements are consistent at the 2.0% confidence level, assuming identical underlying oscillation parameters.

  5. Observational Approach to Chromium Site Remediation - 13266

    SciTech Connect (OSTI)

    Scott Myers, R.

    2013-07-01

    Production reactors at the U.S. Department of Energy's (DOE) Hanford Site in Richland, Washington, required massive quantities of water for reactor cooling and material processing. To reduce corrosion and the build-up of scale in pipelines and cooling systems, sodium dichromate was added to the water feedstock. Spills and other releases at the makeup facilities, as well as leaks from miles of pipelines, have led to numerous areas with chromium-contaminated soil and groundwater, threatening fish populations in the nearby Columbia River. Pump-and-treat systems have been installed to remove chromium from the groundwater, but significant contamination remain in the soil column and poses a continuing threat to groundwater and the Columbia River. Washington Closure Hanford, DOE, and regulators are working on a team approach that implements the observational approach, a strategy for effectively dealing with the uncertainties inherent in subsurface conditions. Remediation of large, complex waste sites at a federal facility is a daunting effort. It is particularly difficult to perform the work in an environment of rapid response to changing field and contamination conditions. The observational approach, developed by geotechnical engineers to accommodate the inherent uncertainties in subsurface conditions, is a powerful and appropriate method for site remediation. It offers a structured means of quickly moving into full remediation and responding to the variations and changing conditions inherent in waste site cleanups. A number of significant factors, however, complicate the application of the observational approach for chromium site remediation. Conceptual models of contamination and site conditions are difficult to establish and get consensus on. Mid-stream revisions to the design of large excavations are time-consuming and costly. And regulatory constraints and contract performance incentives can be impediments to the flexible responses required under the observational approach. The WCH project team is working closely with stakeholders and taking a number of steps to meet these challenges in a continuing effort to remediate chromium contaminated soil in an efficient and cost-effective manner. (authors)

  6. LNG Observer: Second Qatargas train goes onstream

    SciTech Connect (OSTI)

    1997-01-01

    The January-February, 1997 issue of the LNG Observer is presented. The following topics are discussed: second Qatargas train goes onstream; financing for the eighth Indonesian liquefaction train; Koreans take stakes in Oman LNG; US imports and exports of LNG in 1996; A 60% increase in proved reserves on the North West Shelf; proposals for Indian LNG terminal CEDIGAZ forecasts world LNG trade by 2010; growth for North African gas production and exports; and new forecast sees strong growth for Asian gas.

  7. Self-potential observations during hydraulic fracturing

    SciTech Connect (OSTI)

    Moore, Jeffrey R.; Glaser, Steven D.

    2007-09-13

    The self-potential (SP) response during hydraulic fracturing of intact Sierra granite was investigated in the laboratory. Excellent correlation of pressure drop and SP suggests that the SP response is created primarily by electrokinetic coupling. For low pressures, the variation of SP with pressure drop is linear, indicating a constant coupling coefficient (Cc) of -200 mV/MPa. However for pressure drops >2 MPa, the magnitude of the Cc increases by 80% in an exponential trend. This increasing Cc is related to increasing permeability at high pore pressures caused by dilatancy of micro-cracks, and is explained by a decrease in the hydraulic tortuosity. Resistivity measurements reveal a decrease of 2% prior to hydraulic fracturing and a decrease of {approx}35% after fracturing. An asymmetric spatial SP response created by injectate diffusion into dilatant zones is observed prior to hydraulic fracturing, and in most cases this SP variation revealed the impending crack geometry seconds before failure. At rupture, injectate rushes into the new fracture area where the zeta potential is different than in the rock porosity, and an anomalous SP spike is observed. After fracturing, the spatial SP distribution reveals the direction of fracture propagation. Finally, during tensile cracking in a point load device with no water flow, a SP spike is observed that is caused by contact electrification. However, the time constant of this event is much less than that for transients observed during hydraulic fracturing, suggesting that SP created solely from material fracture does not contribute to the SP response during hydraulic fracturing.

  8. First Direct Observation of Spinons and Holons

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

    First Direct Observation of Spinons and Holons Print Spin and charge are inseparable traits of an electron, but in one-dimensional solids, a 40-year-old theory predicts their separation into "collective" modes-as independent excitation quanta called spinons and holons. Angle-resolved photoemission spectroscopy (ARPES) should provide the most direct evidence of this spin-charge separation, as the single quasiparticle peak splits into a spinon-holon two-peak structure. However, despite

  9. First Observation of Plasmarons in Graphene

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

    First Observation of Plasmarons in Graphene Print An international team of scientists performing angle-resolved photoemission spectroscopy (ARPES) experiments at ALS Beamline 7.0.1 have found that composite particles called plasmarons play a vital role in determining graphene's properties. A plasmaron consists of a charge carrier (electron or hole) coupled with a plasmon-an electron density wave. Although plasmarons were proposed theoretically in the late 1960s, and indirect evidence of them has

  10. First Observation of Plasmarons in Graphene

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

    First Observation of Plasmarons in Graphene Print An international team of scientists performing angle-resolved photoemission spectroscopy (ARPES) experiments at ALS Beamline 7.0.1 have found that composite particles called plasmarons play a vital role in determining graphene's properties. A plasmaron consists of a charge carrier (electron or hole) coupled with a plasmon-an electron density wave. Although plasmarons were proposed theoretically in the late 1960s, and indirect evidence of them has

  11. First Direct Observation of Spinons and Holons

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

    First Direct Observation of Spinons and Holons Print Spin and charge are inseparable traits of an electron, but in one-dimensional solids, a 40-year-old theory predicts their separation into "collective" modes-as independent excitation quanta called spinons and holons. Angle-resolved photoemission spectroscopy (ARPES) should provide the most direct evidence of this spin-charge separation, as the single quasiparticle peak splits into a spinon-holon two-peak structure. However, despite

  12. First Direct Observation of Spinons and Holons

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

    First Direct Observation of Spinons and Holons Print Spin and charge are inseparable traits of an electron, but in one-dimensional solids, a 40-year-old theory predicts their separation into "collective" modes-as independent excitation quanta called spinons and holons. Angle-resolved photoemission spectroscopy (ARPES) should provide the most direct evidence of this spin-charge separation, as the single quasiparticle peak splits into a spinon-holon two-peak structure. However, despite

  13. First Observation of Plasmarons in Graphene

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

    First Observation of Plasmarons in Graphene Print An international team of scientists performing angle-resolved photoemission spectroscopy (ARPES) experiments at ALS Beamline 7.0.1 have found that composite particles called plasmarons play a vital role in determining graphene's properties. A plasmaron consists of a charge carrier (electron or hole) coupled with a plasmon-an electron density wave. Although plasmarons were proposed theoretically in the late 1960s, and indirect evidence of them has

  14. First Observation of Plasmarons in Graphene

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

    First Observation of Plasmarons in Graphene Print An international team of scientists performing angle-resolved photoemission spectroscopy (ARPES) experiments at ALS Beamline 7.0.1 have found that composite particles called plasmarons play a vital role in determining graphene's properties. A plasmaron consists of a charge carrier (electron or hole) coupled with a plasmon-an electron density wave. Although plasmarons were proposed theoretically in the late 1960s, and indirect evidence of them has

  15. First Observation of Plasmarons in Graphene

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

    First Observation of Plasmarons in Graphene Print An international team of scientists performing angle-resolved photoemission spectroscopy (ARPES) experiments at ALS Beamline 7.0.1 have found that composite particles called plasmarons play a vital role in determining graphene's properties. A plasmaron consists of a charge carrier (electron or hole) coupled with a plasmon-an electron density wave. Although plasmarons were proposed theoretically in the late 1960s, and indirect evidence of them has

  16. First Observation of Plasmarons in Graphene

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

    First Observation of Plasmarons in Graphene Print An international team of scientists performing angle-resolved photoemission spectroscopy (ARPES) experiments at ALS Beamline 7.0.1 have found that composite particles called plasmarons play a vital role in determining graphene's properties. A plasmaron consists of a charge carrier (electron or hole) coupled with a plasmon-an electron density wave. Although plasmarons were proposed theoretically in the late 1960s, and indirect evidence of them has

  17. Program Management Review Steering Committee Observations

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

    Program Management Review Jim Dooley Forest Concepts, LLC Steering Committee Observations 2 Members Steering Committee: Member Affiliation Jim Dooley Forest Concepts, LLC Dean Dreamel ExxonMobil/University of California, Berkeley Jim Kellis DuPont Mike Lakeman Boeing and Algae Biomass Organization Valri Lightner DOE Loan Programs Office Jack McDonald Independent Shelie Miller University of Michigan Carol Werner Environmental and Energy Study Institute 3 Outline I. BETO Portfolio II. Coordination

  18. ARM - Arctic Lower Troposphere Observed Structure (ALTOS)

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

    govField CampaignsArctic Lower Troposphere Observed Structure (ALTOS) Related Links ALTOS Home ISDAC Home ARM Field Campaigns Home News Department of Energy Announces $7 Million in Funding for Climate Research Field Studies October 23, 2008 Tethered Balloon Headlines Field Campaign at North Slope of Alaska October 28, 2010 Arctic Campaign Cut Short; Spring Restart A Possibility November 3, 2010 ALTOS Backgrounder (PDF, 1.3MB) Experiment Planning Proposal Abstract Science Plan (PDF, 902KB)

  19. Direct Observation of Paramagnons in Palladium

    SciTech Connect (OSTI)

    Doubble, R.; Hayden, S M.; Dai, Pengcheng; Mook Jr, Herbert A; Thompson, James R; Frost, C.

    2010-01-01

    We report an inelastic neutron scattering study of the spin fluctuations in the nearly ferromagnetic element palladium. Dispersive over-damped collective magnetic excitations or 'paramagnons' are observed up to 128 meV. We analyze our results in terms of a Moriya-Lonzarich-type spin-fluctuation model and estimate the contribution of the spin fluctuations to the low-temperature heat capacity. In spite of the paramagnon excitations being relatively strong, their relaxation rates are large. This leads to a small contribution to the low-temperature electronic specific heat.

  20. William Herschel, the First Observational Cosmologist

    ScienceCinema (OSTI)

    Lemonick, Michael [Princeton University and Time Magazine, Princeton, New Jersey, United States

    2010-01-08

    In the late 1700s, a composer, orchestra director and soloist named William Herschel became fascinated with astronomy, and, having built his own reflecting telescope, went out in his garden in Bath, England, one night and discovered Uranus?the first planet in human history ever found by an individual. The feat earned him a lifetime pension from King George III. But Herschel considered the discovery to be relatively unimportant in comparison to his real work: understanding the composition, structure and evolution of the universe. In pursuing that work, he became the first observational cosmologist.

  1. Reported Significant Observation (RSO) studies. Revision 1

    SciTech Connect (OSTI)

    Eicher, R.W.

    1992-12-01

    The Reported Significant Observation (RSO) study used in the field of safety is an information-gathering technique where employee-participants describe situations they have personally witnessed involving good and bad practices and safe and unsafe conditions. This information is useful in the risk assessment process because it focuses on hazards and thereby facilitates their elimination. However, RSO cannot be the only component in a risk assessment program. Used by the Air Force in their aviation psychology program and further developed by John C. Flanagan, RSO is more commonly known as the ``Critical Incident Technique.`` However, the words ``Critical`` and ``Incident`` had other connotations in nuclear safety, prompting early users within the Aerojet Nuclear Company to coin the more fitting title of ``Reported Significant Observations.`` The technique spread slowly in the safety field primarily because the majority of users were researchers interested in after-the-fact data, with application to everyday problems and behavioral factors. RSO was formally recognized as a significant hazard reduction tool during the development of the Management Oversight and Risk Tree (MORT) program for the US Atomic Energy Commission. The Department of Energy (DOE) has, in turn, adopted MORT for its system safety program, and this has resulted in RSO being a modern and viable technique for DOE contractor safety programs.

  2. Boundary Layer Cloudiness Parameterizations Using ARM Observations

    SciTech Connect (OSTI)

    Bruce Albrecht

    2004-09-15

    This study used DOE ARM data and facilities to: (1) study macroscopic properties of continental stratus clouds at SGP and the factors controlling these properties, (2) develop a scientific basis for understanding the processes responsible for the formation of boundary layer clouds using ARM observations in conjunction with simple parametric models and LES, and (3) evaluate cumulus cloud characteristics retrieved from the MMCR operating at TWP-Nauru. In addition we have used high resolution 94 GHz observations of boundary layer clouds and precipitation to: (1) develop techniques for using high temporal resolution Doppler velocities to study large-eddy circulations and turbulence in boundary layer clouds and estimate the limitations of using current and past MMCR data for boundary layer cloud studies, (2) evaluate the capability and limitations of the current MMCR data for estimating reflectivity, vertical velocities, and spectral under low- signal-to-noise conditions associated with weak no n-precipitating clouds, (3) develop possible sampling modes for the new MMCR processors to allow for adequate sampling of boundary layer clouds, and (4) retrieve updraft and downdraft structures under precipitating conditions.

  3. Fermi LAT Observations of LS 5039

    SciTech Connect (OSTI)

    Abdo, A.A.; Ackermann, M.; Ajello, M.; Atwood, W.B.; Axelsson, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Baughman, B.M.; Bechtol, K.; Bellazzini, R.; Berenji, B.; Blandford, R.D.; Bloom, E.D.; Bonamente, E.; Borgland, A.W.; Bregeon, J.; Brez, A.; Brigida, M.; Bruel, P.; /more authors..

    2012-03-29

    The first results from observations of the high-mass X-ray binary LS 5039 using the Fermi Gamma-ray Space Telescope data between 2008 August and 2009 June are presented. Our results indicate variability that is consistent with the binary period, with the emission being modulated with a period of 3.903 {+-} 0.005 days; the first detection of this modulation at GeV energies. The light curve is characterized by a broad peak around superior conjunction in agreement with inverse Compton scattering models. The spectrum is represented by a power law with an exponential cutoff, yielding an overall flux (100 MeV-300 GeV) of 4.9 {+-} 0.5(stat) {+-} 1.8(syst) x 10{sup -7} photon cm{sup -2} s{sup -1}, with a cutoff at 2.1 {+-} 0.3(stat) {+-} 1.1(syst) GeV and photon index {Gamma} = 1.9 {+-} 0.1(stat) {+-} 0.3(syst). The spectrum is observed to vary with orbital phase, specifically between inferior and superior conjunction. We suggest that the presence of a cutoff in the spectrum may be indicative of magnetospheric emission similar to the emission seen in many pulsars by Fermi.

  4. Head Observation Organizer (HObO)

    SciTech Connect (OSTI)

    Steven Predmore

    2008-03-06

    The Head Observation Organizer, HObO, is a computer program that stores and manages measured ground-water levels. HObO was developed to help ground-water modelers compile, manage, and document water-level data needed to calibrate ground-water models. Well-construction and water-level data from the U.S. Geological Survey National Water Database (NWIS) easily can be imported into HObO from the NWIS web site (NWISWeb). The water-level data can be flagged to determine which data will be included in the calibration data set. The utility program HObO_NWISWeb was developed to simplify the down loading of well and water-level data from NWISWeb. An ArcGIS NWISWeb Extension was developed to retrieve site information from NWISWeb. A tutorial is presented showing the basic elements of HObO.

  5. Global Volunteer Observing Ship (VOS) Program Data

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

    CDIAC provides data management support for the Global Volunteer Observing Ship (VOS) Program. The VOS project is coordinated by the UNESCO International Ocean Carbon Coordination Project (IOCCP). The international groups from 14 countries have been outfitting research ships and commercial vessels with automated CO2 sampling equipment to analyze the carbon exchange between the ocean and atmosphere. [copied from http://cdiac.ornl.gov/oceans/genInfo.html] CDIAC provides a map interface with the shipping routes of the 14 countries involved marked in different colors. Clicking on the ship's name on that route brings up information about the vessel, the kinds of measurements collected and the timeframe, links to project pages, and, most important, the links to the data files themselves. The 14 countries are: United States, United Kingdom, Japan, France, Germany, Australia, Canada, Spain, Norway, New Zealand, China (including Taiwan), Iceland, and the Netherlands. Both archived and current, underway data can be accessed from the CDIAC VOS page.

  6. Constraint effects observed in crack initiation stretch

    SciTech Connect (OSTI)

    Lambert, D.M.; Ernst, H.A.

    1995-12-31

    The current paper characterizes constraint in fracture: J-modified resistance (Jr) curves were developed for two tough structural materials, 6061-T651 (aluminum) and IN718-STA1 (nickel-base superalloy). A wide variety of configurations was tested to consider load configurations from bending to tension including three specimen types (compact tension, center-crack tension, and single-edge notched tension), and a range of ligament lengths and thicknesses, as well as side-grooved and smooth-sided ligaments. The Jr curves exhibited an inflection point after some crack extension, and the data were excluded beyond the inflection. Qualified Jr curves for the two materials showed similar behavior, but R-curves were identical for equal ligament length-to-thickness ratio (RL), for the aluminum alloy, with increasing slope for increasing RL, while for the nickel, the resistance curves aligned for equal ligament thickness, B, and the slope increased for decreasing B. Displacements at the original crack tip (CToD) were recorded throughout the test for several specimens. CToD-versus-crack extension curves were developed, and data were excluded beyond the inflection point (as with the Jr curves). The data collapsed into two distinct curves, thought to represent the surface, plane stress effect and the central, plane strain effect. This was observed for both materials. A technique called profiling is presented for the aluminum alloy only, where the crack face displacements are recorded at the final point of the test as a function of the position throughout the crack cavity, along with an effort to extract the observations in a usable form. Displacements were consistent throughout the cross-section at and behind the original crack tip. In the region where the crack grew, this displacement was developed by a combination of stretch and crack growth. The stretch required to initiate crack extension was a function of the depth beneath the surface into the cross-section.

  7. Resolved multifrequency radio observations of GG Tau

    SciTech Connect (OSTI)

    Andrews, Sean M.; Birnstiel, T.; Rosenfeld, K. A.; Wilner, D. J.; Chandler, Claire J.; Pérez, L. M.; Isella, Andrea; Ricci, L.; Carpenter, J. M.; Calvet, N.; Corder, S. A.; Deller, A. T.; Dullemond, C. P.; Greaves, J. S.; Harris, R. J.; Henning, Th.; Linz, H.; Kwon, W.; Lazio, J.; Mundy, L. G.; and others

    2014-06-01

    We present subarcsecond resolution observations of continuum emission associated with the GG Tau quadruple star system at wavelengths of 1.3, 2.8, 7.3, and 50 mm. These data confirm that the GG Tau A binary is encircled by a circumbinary ring at a radius of 235 AU with a FWHM width of ∼60 AU. We find no clear evidence for a radial gradient in the spectral shape of the ring, suggesting that the particle size distribution is spatially homogeneous on angular scales ≳0.''1. A central point source, likely associated with the primary component (GG Tau Aa), exhibits a composite spectrum from dust and free-free emission. Faint emission at 7.3 mm is observed toward the low-mass star GG Tau Ba, although its origin remains uncertain. Using these measurements of the resolved, multifrequency emission structure of the GG Tau A system, models of the far-infrared to radio spectrum are developed to place constraints on the grain size distribution and dust mass in the circumbinary ring. The non-negligible curvature present in the ring spectrum implies a maximum particle size of 1-10 mm, although we are unable to place strong constraints on the distribution shape. The corresponding dust mass is 30-300 M {sub ⊕}, at a temperature of 20-30 K. We discuss how this significant concentration of relatively large particles in a narrow ring at a large radius might be produced in a local region of higher gas pressures (i.e., a particle 'trap') located near the inner edge of the circumbinary disk.

  8. Observational tests for ?(t)CDM cosmology

    SciTech Connect (OSTI)

    Pigozzo, C.; Carneiro, S.; Dantas, M.A.; Alcaniz, J.S. E-mail: aldinez@on.br E-mail: alcaniz@on.br

    2011-08-01

    We investigate the observational viability of a class of cosmological models in which the vacuum energy density decays linearly with the Hubble parameter, resulting in a production of cold dark matter particles at late times. Similarly to the flat ?CDM case, there is only one free parameter to be adjusted by the data in this class of ?(t)CDM scenarios, namely, the matter density parameter. To perform our analysis we use three of the most recent SNe Ia compilation sets (Union2, SDSS and Constitution) along with the current measurements of distance to the BAO peaks at z = 0.2 and z = 0.35 and the position of the first acoustic peak of the CMB power spectrum. We show that in terms of ?{sup 2} statistics both models provide good fits to the data and similar results. A quantitative analysis discussing the differences in parameter estimation due to SNe light-curve fitting methods (SALT2 and MLCS2k2) is studied using the current SDSS and Constitution SNe Ia compilations. A matter power spectrum analysis using the 2dFGRS is also performed, providing a very good concordance with the constraints from the SDSS and Constitution MLCS2k2 data.

  9. Optical monitor for observing turbulent flow

    DOE Patents [OSTI]

    Albrecht, Georg F. (Livermore, CA); Moore, Thomas R. (Rochester, NY)

    1992-01-01

    The present invention provides an apparatus and method for non-invasively monitoring turbulent fluid flows including anisotropic flows. The present invention uses an optical technique to filter out the rays travelling in a straight line, while transmitting rays with turbulence induced fluctuations in time. The output is two dimensional, and can provide data regarding the spectral intensity distribution, or a view of the turbulence in real time. The optical monitor of the present invention comprises a laser that produces a coherent output beam that is directed through a fluid flow, which phase-modulates the beam. The beam is applied to a temporal filter that filters out the rays in the beam that are straight, while substantially transmitting the fluctuating, turbulence-induced rays. The temporal filter includes a lens and a photorefractive crystal such as BaTiO.sub.3 that is positioned in the converging section of the beam near the focal plane. An imaging system is used to observe the filtered beam. The imaging system may take a photograph, or it may include a real time camera that is connected to a computer. The present invention may be used for many purposes including research and design in aeronautics, hydrodynamics, and combustion.

  10. RECONCILING THE OBSERVED STAR-FORMING SEQUENCE WITH THE OBSERVED STELLAR MASS FUNCTION

    SciTech Connect (OSTI)

    Leja, Joel; Van Dokkum, Pieter G.; Franx, Marijn; Whitaker, Katherine E.

    2015-01-10

    We examine the connection between the observed star-forming sequence (SFR ? M {sup ?}) and the observed evolution of the stellar mass function in the range 0.2 < z < 2.5. We find that the star-forming sequence cannot have a slope ? ? 0.9 at all masses and redshifts because this would result in a much higher number density at 10 < log (M/M {sub ?}) < 11 by z = 1 than is observed. We show that a transition in the slope of the star-forming sequence, such that ? = 1 at log (M/M {sub ?}) < 10.5 and ? = 0.7-0.13z (Whitaker et al.) at log (M/M {sub ?}) > 10.5, greatly improves agreement with the evolution of the stellar mass function. We then derive a star-forming sequence that reproduces the evolution of the mass function by design. This star-forming sequence is also well described by a broken power law, with a shallow slope at high masses and a steep slope at low masses. At z = 2, it is offset by ?0.3 dex from the observed star-forming sequence, consistent with the mild disagreement between the cosmic star formation rate (SFR) and recent observations of the growth of the stellar mass density. It is unclear whether this problem stems from errors in stellar mass estimates, errors in SFRs, or other effects. We show that a mass-dependent slope is also seen in other self-consistent models of galaxy evolution, including semianalytical, hydrodynamical, and abundance-matching models. As part of the analysis, we demonstrate that neither mergers nor hidden low-mass quiescent galaxies are likely to reconcile the evolution of the mass function and the star-forming sequence. These results are supported by observations from Whitaker et al.

  11. Observational Constraints on the Nature of the Dark Energy: First...

    Office of Scientific and Technical Information (OSTI)

    Observational Constraints on the Nature of the Dark Energy: First Cosmological Results From the ESSENCE Supernova Survey Citation Details In-Document Search Title: Observational...

  12. ARM - Field Campaign - The ARM Pilot Radiation Observation Experiment...

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

    from Observations in the ARM Pilot Radiation Observation Experiment Campaign Data Sets IOP Participant Data Source Description Final Data Tooman WSI Order Data Westwater ftirraob...

  13. Observation of Large Photoacoustic Signal Phase Changes During...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: Observation of Large Photoacoustic Signal Phase Changes During a Diffusion Process Citation Details In-Document Search Title: Observation of Large Photoacoustic...

  14. Aided by Simulations, Scientists Observe Atomic Collapse State

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

    Collapse State Observed Aided by Simulations, Scientists Observe Atomic Collapse State Quantum Mechanics Prediction Confirmed in Graphene Using NERSC's Hopper April 26, 2013...

  15. Observation of a Macroscopically Quantum-Entangled Insulator

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

    Observation of a Macroscopically Quantum-Entangled Insulator Observation of a Macroscopically Quantum-Entangled Insulator Print Wednesday, 27 May 2009 00:00 It has recently been...

  16. Net Zero Waste - Tools and Technical Support ...and other observations...

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

    Net Zero Waste - Tools and Technical Support ...and other observations Net Zero Waste - Tools and Technical Support ...and other observations Presentation at Waste-to-Energy using...

  17. USGS-Earth Resources Observation and Science (EROS) Center |...

    Open Energy Info (EERE)

    USGS-Earth Resources Observation and Science (EROS) Center Jump to: navigation, search Tool Summary LAUNCH TOOL Name: USGS-Earth Resources Observation and Science (EROS) Center...

  18. Common Cyber Security Vulnerabilities Observed in Control System...

    Energy Savers [EERE]

    Common Cyber Security Vulnerabilities Observed in Control System Assessments by the INL NSTB Program Common Cyber Security Vulnerabilities Observed in Control System Assessments by...

  19. Observation of Ordered Structures in Counterion Layers near Wet...

    Office of Scientific and Technical Information (OSTI)

    Observation of Ordered Structures in Counterion Layers near Wet Charged Surfaces: A Potential Mechanism for Charge Inversion Citation Details In-Document Search Title: Observation ...

  20. ARM - Field Campaign - Arctic Lower Troposphere Observed Structure...

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

    govCampaignsArctic Lower Troposphere Observed Structure (ALTOS) Campaign Links Science Plan ALTOS Website Related Campaigns Supplement to Arctic Lower Troposphere Observed...

  1. Far infrared supplement: Catalog of infrared observations, second edition

    SciTech Connect (OSTI)

    Gezari, D.Y.; Schmitz, M.; Mead, J.M.

    1988-08-01

    The Far Infrared Supplement: Catalog of Infrared Observations summarizes all infrared astronomical observations at far infrared wavelengths (5 to 1000 microns) published in the scientific literature from 1965 through 1986. The Supplement list contain 25 percent of the observations in the full Catalog of Infrared Observations (CIO), and essentially eliminates most visible stars from the listings. The Supplement is thus more compact than the main catalog, and is intended for easy reference during astronomical observations. The Far Infrared Supplement (2nd Edition) includes the Index of Infrared Source Positions and the Bibliography of Infrared Astronomy for the subset of far infrared observations listed.

  2. CX-007539: Categorical Exclusion Determination

    Office of Energy Efficiency and Renewable Energy (EERE)

    Investigating Marine Boundary Layer Parameterizations by Combining Observations with Models Via State Estimation CX(s) Applied: A9 Date: 01/18/2012 Location(s): Colorado Offices(s): Golden Field Office

  3. Observation of 690 MV m^-1 Electron Accelerating Gradient with...

    Office of Scientific and Technical Information (OSTI)

    Observation of 690 MV m-1 Electron Accelerating Gradient with a Laser-Driven Dielectric Microstructure Citation Details In-Document Search Title: Observation of 690 MV m-1...

  4. Kalman filter data assimilation: Targeting observations and parameter estimation

    SciTech Connect (OSTI)

    Bellsky, Thomas Kostelich, Eric J.; Mahalov, Alex

    2014-06-15

    This paper studies the effect of targeted observations on state and parameter estimates determined with Kalman filter data assimilation (DA) techniques. We first provide an analytical result demonstrating that targeting observations within the Kalman filter for a linear model can significantly reduce state estimation error as opposed to fixed or randomly located observations. We next conduct observing system simulation experiments for a chaotic model of meteorological interest, where we demonstrate that the local ensemble transform Kalman filter (LETKF) with targeted observations based on largest ensemble variance is skillful in providing more accurate state estimates than the LETKF with randomly located observations. Additionally, we find that a hybrid ensemble Kalman filter parameter estimation method accurately updates model parameters within the targeted observation context to further improve state estimation.

  5. NS&T Managment Observations - 1st Quarter

    SciTech Connect (OSTI)

    David Gianotto

    2014-06-01

    The INL Management Observation Program (MOP) is designed to improve managers and supervisors understanding of work being performed by employees and the barriers impacting their success. The MOP also increases workers understanding of managements expectations as they relate to safety, security, quality, and work performance. Management observations (observations) are designed to improve the relationship and trust between employees and managers through increased engagement and interactions between managers and researchers in the field. As part of continuous improvement, NS&T management took initiative to focus on the participation and quality of observations in FY 14. This quarterly report is intended to (a) summarize the participation and quality of managements observations, (b) assess observations for commonalities or trends related to facility or process barriers impacting research, and (c) provide feedback and make recommendations for improvements NS&Ts MOP.

  6. Radioactivity in Precipitation: Methods & Observations from Savannah River

    Office of Environmental Management (EM)

    Site | Department of Energy Radioactivity in Precipitation: Methods & Observations from Savannah River Site Radioactivity in Precipitation: Methods & Observations from Savannah River Site Presentation from the 33rd Tritium Focus Group Meeting held in Aiken, South Carolina on April 22-24, 2014. PDF icon Radioactivity in Precipitation: Methods & Observations from Savannah River Site More Documents & Publications DOE-HDBK-1129-2008 F-Tank Farm Performance Assessment, Rev 1

  7. Properties of tropical convection observed by ARM millimeter-radars

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

    Properties of tropical convection observed by ARM millimeter-radars Haynes, John Colorado State University Stephens, Graeme Colorado State University Category: Cloud Properties The results of an analysis of tropical cloud systems observed from a variety of vertically pointing radar systems are described. In particular, observations taken during five years of operation of the ARM millimeter wavelength radar system (MMCR) at Manus Island in the Tropical West Pacific region are characterized into

  8. Nanometer-scale temperature imaging for independent observation of Joule

    Office of Scientific and Technical Information (OSTI)

    and Peltier effects in phase change memory devices (Journal Article) | SciTech Connect Nanometer-scale temperature imaging for independent observation of Joule and Peltier effects in phase change memory devices Citation Details In-Document Search Title: Nanometer-scale temperature imaging for independent observation of Joule and Peltier effects in phase change memory devices This paper reports a technique for independent observation of nanometer-scale Joule heating and thermoelectric

  9. Direct observation of resistive heating at graphene wrinkles and grain

    Office of Scientific and Technical Information (OSTI)

    boundaries (Journal Article) | SciTech Connect Direct observation of resistive heating at graphene wrinkles and grain boundaries Citation Details In-Document Search Title: Direct observation of resistive heating at graphene wrinkles and grain boundaries We directly measure the nanometer-scale temperature rise at wrinkles and grain boundaries (GBs) in functioning graphene devices by scanning Joule expansion microscopy with 50 nm spatial and 0.2K temperature resolution. We observe a small

  10. Current and Past 48 Hours HMS Observations - Hanford Site

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

    Hanford Meteorological Station Current and Past 48 Hours HMS Observations 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 Current and Past 48 Hours HMS Observations Email Email Page | Print Print Page |Text Increase Font Size Decrease Font Size Date Ceiling (ft) Visibility (miles) Liquid

  11. ARM - Lesson Plans: Observing Wind Speed and Cloudiness

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

    Observing Wind Speed and Cloudiness Outreach Home Room News Publications Traditional Knowledge Kiosks Barrow, Alaska Tropical Western Pacific Site Tours Contacts Students Study Hall About ARM Global Warming FAQ Just for Fun Meet our Friends Cool Sites Teachers Teachers' Toolbox Lesson Plans Lesson Plans: Observing Wind Speed and Cloudiness Objective The objective is to demonstrate students' skills in observing the atmosphere, specifically in terms of wind speed and cloudiness. Materials Each

  12. Enterprise Assessments - Operational Awareness Record of the Observation of

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

    the Waste Isolation Pilot Plant Horizon-14 Exercise - January 2015 | Department of Energy - Operational Awareness Record of the Observation of the Waste Isolation Pilot Plant Horizon-14 Exercise - January 2015 Enterprise Assessments - Operational Awareness Record of the Observation of the Waste Isolation Pilot Plant Horizon-14 Exercise - January 2015 December 2014 Operational Awareness Record of the Observation of the Waste Isolation Pilot Plant Horizon-14 Exercise (EA-WIPP-2014-12-08) The

  13. Ultrafast myoglobin structural dynamics observed with an X-ray...

    Office of Scientific and Technical Information (OSTI)

    to propagate through the protein as a quake-like intramolecular motion. Here we report direct experimental evidence of such 'proteinquake' observed in myoglobin through...

  14. Observations of tropical clouds from the upgraded MMCR at Darwin...

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

    from the upgraded MMCR at Darwin and comparisons with C-Pol and satellite observations Jensen, Michael Brookhaven National Laboratory Kollias, Pavlos Brookhaven National Laboratory...

  15. Title: Radar-observed convective characteristics during TWP-ICE

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

    will describe the convective systems observed during the project by two scanning C-band Doppler radars, one of which will provide dual-polarization measurements, and ARM's...

  16. Using ARM TWP Nauru Observations to Evaluate a Simple Thermodynamic...

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

    Using ARM TWP Nauru Observations to Evaluate a Simple Thermodynamic Model of the Subcloud Layer Under Fair-Weather Cumulus Conditions Albrecht, Bruce University of Miami Kollias,...

  17. Observed Relations Between Snowfall Microphysics and Triple-Frequency...

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

    to derive important snowfall microphysical parameters like median mass diameter, fractal dimension, or particle habit. These observations further revealed that naturally occurring...

  18. Intercomparison of model simulations of mixed-phase clouds observed...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: Intercomparison of model simulations of mixed-phase clouds observed during the ARM Mixed-Phase Arctic Cloud Experiment. I: Single layer cloud Citation Details ...

  19. Observation of Ion Acceleration and Heating during Collisionless...

    Office of Scientific and Technical Information (OSTI)

    ... This unique in-plane potential is established by electron dynamics around the electron ... Furthermore, heat conduction is too large to sustain the observed ion temperature ...

  20. Nanometer-scale temperature imaging for independent observation...

    Office of Scientific and Technical Information (OSTI)

    temperature imaging for independent observation of Joule and Peltier effects in phase change memory devices Citation Details In-Document Search Title: Nanometer-scale temperature ...

  1. Observation Wells At East Brawley Area (Matlick & Jayne, 2008...

    Open Energy Info (EERE)

    Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Observation Wells At East Brawley Area (Matlick & Jayne, 2008) Exploration Activity Details...

  2. COLLOQUIUM: Initial Observations from the New Horizons Flyby...

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

    Initial Observations from the New Horizons Flyby of Pluto Dr. Andy Cheng Johns Hopkins University Applied Physics Laboratory Colloquium Committee: The Princeton Plasma...

  3. Observation Wells At Blue Mountain Area (Warpinski, Et Al., 2004...

    Open Energy Info (EERE)

    Blue Mountain Area (Warpinski, Et Al., 2004) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Observation Wells At Blue Mountain Area (Warpinski,...

  4. Observation Wells At Lightning Dock Geothermal Area (Reeder,...

    Open Energy Info (EERE)

    Geothermal Area (Reeder, 1957) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Observation Wells At Lightning Dock Geothermal Area (Reeder, 1957)...

  5. Observation Wells At Lightning Dock Area (Warpinski, Et Al.,...

    Open Energy Info (EERE)

    Area (Warpinski, Et Al., 2004) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Observation Wells At Lightning Dock Area (Warpinski, Et Al., 2004)...

  6. Observation Wells At The Needles Area (DOE GTP) | Open Energy...

    Open Energy Info (EERE)

    The Needles Area (DOE GTP) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Observation Wells At The Needles Area (DOE GTP) Exploration Activity...

  7. Observation Wells At Mccoy Geothermal Area (DOE GTP) | Open Energy...

    Open Energy Info (EERE)

    Mccoy Geothermal Area (DOE GTP) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Observation Wells At Mccoy Geothermal Area (DOE GTP) Exploration...

  8. Simultaneous observation of nascent plasma and bubble induced...

    Office of Scientific and Technical Information (OSTI)

    in water with various pulse durations Citation Details In-Document Search Title: Simultaneous observation of nascent plasma and bubble induced by laser ablation in water with ...

  9. Genetically encoded sensors enable real-time observation of metabolite...

    Office of Scientific and Technical Information (OSTI)

    8, 2016 Title: Genetically encoded sensors enable real-time observation of metabolite production Authors: Rogers, Jameson K. ; Church, George M. Publication Date: 2016-02-08 ...

  10. Direct observation of resistive heating at graphene wrinkles...

    Office of Scientific and Technical Information (OSTI)

    Direct observation of resistive heating at graphene wrinkles and grain boundaries Citation ... Sponsoring Org: SC USDOE - Office of Science (SC) Country of Publication: United ...

  11. Influence of Analysis Method on the Experimentally Observed Capacitanc...

    Office of Scientific and Technical Information (OSTI)

    of the Gold-Ionic Liquid Interface. Citation Details In-Document Search Title: Influence of Analysis Method on the Experimentally Observed Capacitance of the Gold-Ionic ...

  12. Researchers Directly Observe Oxygen Signature in the Oxygen-evolving...

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

    Researchers Directly Observe Oxygen Signature in the Oxygen-evolving Complex of Photosynthesis Arguably the most important chemical reaction on earth is the photosynthetic...

  13. How Are You Observing Energy Awareness Month? | Department of Energy

    Energy Savers [EERE]

    Observing Energy Awareness Month? How Are You Observing Energy Awareness Month? October 7, 2010 - 7:30am Addthis October is Energy Awareness Month, and we think a great way to celebrate would be to make an improvement that gets you a tax credit. But there are plenty of other ways you could observe Energy Awareness Month help spread the word about saving energy. So tell us: How are you observing Energy Awareness Month? Each Thursday, you have the chance to share your thoughts on a question about

  14. Model-Observation "Data Cubes" for the DOE Atmospheric Radiation...

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

    Model-Observation "Data Cubes" for the DOE Atmospheric Radiation Measurement Facility's ... Program through its Atmospheric Radiation Measurement Facility. 2. Data Cube ...

  15. Observing the Sparks of Life | Photosynthetic Antenna Research Center

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

    Observing the Sparks of Life December 31, 2013 Observing the Sparks of Life EFRC researchers isolate a photosynthetic complex - arguably the most important bit of organic chemistry on the planet - in its complete functioning state. http://science.energy.gov/discovery-and-innovation/stories/2013/127045/ In the News

  16. NS&T Management Observations - 3rd Quarter

    SciTech Connect (OSTI)

    David Gianotto

    2014-07-01

    The INL Management Observation Program (MOP) is designed to improve managers and supervisors understanding of work being performed by employees and the barriers impacting their success. The MOP also increases workers understanding of managements expectations as they relate to safety, security, quality, and work performance. Management observations are designed to improve the relationship and trust between employees and managers through increased engagement and interactions between managers and researchers in the field. As part of continuous improvement, NS&T management took initiative to focus on the participation and quality of observations in FY 14. This quarterly report is intended to (a) summarize the participation and quality of managements observations, (b) assess observations for commonalities or trends related to facility or process barriers impacting research, and (c) provide feedback and make recommendations for improvements NS&Ts MOP.

  17. Warm Bias and Parameterization of Boundary Upwelling in Ocean Models

    SciTech Connect (OSTI)

    Cessi, Paola; Wolfe, Christopher

    2012-11-06

    It has been demonstrated that Eastern Boundary Currents (EBC) are a baroclinic intensification of the interior circulation of the ocean due to the emergence of mesoscale eddies in response to the sharp buoyancy gradients driven by the wind-stress and the thermal surface forcing. The eddies accomplish the heat and salt transport necessary to insure that the subsurface flow is adiabatic, compensating for the heat and salt transport effected by the mean currents. The EBC thus generated occurs on a cross-shore scale of order 20-100 km, and thus this scale needs to be resolved in climate models in order to capture the meridional transport by the EBC. Our result indicate that changes in the near shore currents on the oceanic eastern boundaries are linked not just to local forcing, such as coastal changes in the winds, but depend on the basin-wide circulation as well.

  18. Current practices and new technology in ocean engineering

    SciTech Connect (OSTI)

    McGuinness, T.; Shih, H.H.

    1986-01-01

    This book presents the papers given at a conference on wave power and marine engineering. Topics considered at the conference included remote sensing, ocean current measurement, air and spaceborne instrumentation, marine dynamics, real-time measurements, telemetry systems, seafloor measurement, computer-based data acquisition, materials and devices for underwater work systems, ocean system design analysis and reliability, ocean structure fatigue life prediction, underwater life support systems, sensor design, ocean thermal energy conversion, and wave energy converters.

  19. ARM - Field Campaign - Observations and Modeling of the Green...

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

    2 ARM Data Discovery Browse Data Related Campaigns Observations and Modeling of the Green Ocean Amazon (GOAMAZON 2014) 2014.01.01, Martin, AMF Comments? We would love to hear...

  20. Press Pass - Press Release - DZero ZZ diboson observation

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

    of the ZZ diboson make its discovery an essential prelude to finding or excluding the Higgs boson at the Tevatron. The observation of the ZZ, announced at a Fermilab seminar on...

  1. Observation of the Goos-Haenchen Shift with Neutrons (Journal...

    Office of Scientific and Technical Information (OSTI)

    This phenomenon was suggested by Sir Isaac Newton, but it was not until 1947 that the effect was experimentally observed by Goos and Haenchen. We provide the first direct, ...

  2. GALEX DIFFUSE OBSERVATIONS OF THE SKY: THE DATA

    SciTech Connect (OSTI)

    Murthy, Jayant

    2014-08-01

    I present tabulations of the diffuse observations made by the GALEX spacecraft in two UV bands (FUV: 1539 and NUV: 2316 ) from the (almost) final data release of the GALEX spacecraft (GR6/GR7). This data release includes all the FUV observations and the majority of the NUV observations. I discuss overall trends in the data but the primary purpose of this paper is to make the data available to the public. The data files described in this paper are hosted by the Mikulski Archive for Space Telescopes at the Space Telescope Science Insitute from whence they may be downloaded. For ease of use, I have also created maps of the diffuse radiation in both bands over the entire observed sky at 6' resolution.

  3. Sweetspot: Near-infrared observations of 13 type Ia supernovae...

    Office of Scientific and Technical Information (OSTI)

    With only one to three points per light curve and a prior on the time of maximum from the ... These observations continue to demonstrate the improved standard brightness of SNe Ia in ...

  4. Intercomparison of model simulations of mixed-phase clouds observed...

    Office of Scientific and Technical Information (OSTI)

    Radiation Measurement (ARM) program's Mixed-Phase Arctic Cloud Experiment. The observed cloud occurred in a well-mixed boundary layer with a cloud top temperature of -15 C. The ...

  5. Direct Observation of the Oxygenated Species during Oxygen Reduction...

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

    Direct Observation of the Oxygenated Species during Oxygen Reduction on a Platinum Fuel Cell Cathode Friday, December 20, 2013 Fuel Cell Figure 1 Figure 1. In situ x-ray...

  6. Observation of a Macroscopically Quantum-Entangled Insulator

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

    Observation of a Macroscopically Quantum-Entangled Insulator Print It has recently been proposed that insulators with large band gaps and strong spin-orbit coupling can host a new...

  7. ARM - Publications: Science Team Meeting Documents: An Observational...

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

    use a simple parcel model with the nearest preceding sounding to estimate the entrainment rate (assuming constant entrainment rate with height) needed to get the observed cloud-top...

  8. Observations of flow patterns in a spray dryer

    SciTech Connect (OSTI)

    Southwell, D.B.; Langrish, T.A.G.

    2000-03-01

    Experiments have been performed on a pilot scale, cylinder-on-cone spray dryer fitted with a vaned-wheel atomizer to observe air flow patterns, with and without water spray. A combination of tufts, smoke streams and a laser light sheet, was used to provide information about regions of recirculation, flow stability, spray trajectories and wall deposition. While atomizer-induced swirl dominated the flow patterns under typical operating conditions, some instability was observed, although different in type, for situations with and without atomizer rotation. Clockwise eddies were observed to form and collapse between the wall and the strongly anti-clockwise swirling core created by anti-clockwise atomizer rotation. Without swirl, large portions of the recirculation zones at the walls were observed to have a weak tendency to change randomly between clockwise, anti-clockwise and chaotic behavior.

  9. Radiosonde observations at Pt. Reyes and cloud properties retrieved...

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

    Radiosonde observations at Pt. Reyes and cloud properties retrieved from GOES-WEST Inoue, Toshiro MRIJMA Category: Field Campaigns Low-level cloud formed off the west coast of...

  10. ARM - Field Campaign - Observations and Modeling of the Green...

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

    would love to hear from you Send us a note below or call us at 1-888-ARM-DATA. Send Campaign : Observations and Modeling of the Green Ocean Amazon: Parsivel2 2014.05.12 -...

  11. Jacob P. Fugal, Scott Spuler Earth Observing Laboratory NCAR...

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

    2 (HOLODEC 2) Jacob P. Fugal, Scott Spuler Earth Observing Laboratory NCAR, Boulder, CO USA & Raymond A. Shaw Physics Department, michigan Tech Houghton, MI USA C-130 Hercules Q...

  12. ITEP Webinar: About the Local Environmental Observer (LEO) Network

    Broader source: Energy.gov [DOE]

    Attend this Institute for Tribal Environmental Professionals (ITEP) webinar and learn how the Local Environmental Observer (LEO) Network provides a model for engaging communities; connecting with technical experts and resources; and disseminating information about specific events and the impacts, needs, and responses. This webinar will introduce LEO as a resource comprised of local experts who collect observations about unusual environmental events and serve as the eyes, ears and voice of environmental change in their communities.

  13. Observation of a Macroscopically Quantum-Entangled Insulator

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

    Observation of a Macroscopically Quantum-Entangled Insulator Observation of a Macroscopically Quantum-Entangled Insulator Print Wednesday, 27 May 2009 00:00 It has recently been proposed that insulators with large band gaps and strong spin-orbit coupling can host a new phase of quantum matter called a topological insulator that is characterized by entangled wavefunctions. The proposal has now been realized by an international collaboration led by researchers from Princeton University who studied

  14. Observation of Ordered Structures in Counterion Layers near Wet Charged

    Office of Scientific and Technical Information (OSTI)

    Surfaces: A Potential Mechanism for Charge Inversion (Journal Article) | SciTech Connect Observation of Ordered Structures in Counterion Layers near Wet Charged Surfaces: A Potential Mechanism for Charge Inversion Citation Details In-Document Search Title: Observation of Ordered Structures in Counterion Layers near Wet Charged Surfaces: A Potential Mechanism for Charge Inversion Authors: Miller, Mitchell ; Chu, Miaoqi ; Lin, Binhua ; Meron, Mati ; Dutta, Pulak [1] ; NWU) [2] + Show Author

  15. Observation of the Second Harmonic in Thomson Scattering from Relativistic

    Office of Scientific and Technical Information (OSTI)

    Electrons (Journal Article) | SciTech Connect Journal Article: Observation of the Second Harmonic in Thomson Scattering from Relativistic Electrons Citation Details In-Document Search Title: Observation of the Second Harmonic in Thomson Scattering from Relativistic Electrons A free relativistic electron in an electromagnetic field is a pure case of a light-matter interaction. In the laboratory environment, this interaction can be realized by colliding laser pulses with electron beams

  16. Genetically encoded sensors enable real-time observation of metabolite

    Office of Scientific and Technical Information (OSTI)

    production (Journal Article) | SciTech Connect Genetically encoded sensors enable real-time observation of metabolite production Citation Details In-Document Search This content will become publicly available on August 8, 2016 Title: Genetically encoded sensors enable real-time observation of metabolite production Authors: Rogers, Jameson K. ; Church, George M. Publication Date: 2016-02-08 OSTI Identifier: 1237386 Type: Published Article Journal Name: Proceedings of the National Academy of

  17. Inflation after false vacuum decay: Observational prospects after Planck

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect Inflation after false vacuum decay: Observational prospects after Planck Citation Details In-Document Search Title: Inflation after false vacuum decay: Observational prospects after Planck Authors: Bousso, Raphael ; Harlow, Daniel ; Senatore, Leonardo Publication Date: 2015-04-22 OSTI Identifier: 1181415 Grant/Contract Number: FG02-12ER41854; AC02-05CH11231 Type: Published Article Journal Name: Physical Review D Additional Journal Information: Journal

  18. Influence of Analysis Method on the Experimentally Observed Capacitance at

    Office of Scientific and Technical Information (OSTI)

    the Gold-Ionic Liquid Interface. (Journal Article) | SciTech Connect Influence of Analysis Method on the Experimentally Observed Capacitance at the Gold-Ionic Liquid Interface. Citation Details In-Document Search Title: Influence of Analysis Method on the Experimentally Observed Capacitance at the Gold-Ionic Liquid Interface. Abstract not provided. Authors: Small, Leo J ; Wheeler, David Roger Publication Date: 2014-01-01 OSTI Identifier: 1140634 Report Number(s): SAND2014-0418J Journal ID:

  19. Influence of Analysis Method on the Experimentally Observed Capacitance of

    Office of Scientific and Technical Information (OSTI)

    the Gold-Ionic Liquid Interface. (Journal Article) | SciTech Connect Influence of Analysis Method on the Experimentally Observed Capacitance of the Gold-Ionic Liquid Interface. Citation Details In-Document Search Title: Influence of Analysis Method on the Experimentally Observed Capacitance of the Gold-Ionic Liquid Interface. Abstract not provided. Authors: Small, Leo J ; Wheeler, David Roger Publication Date: 2013-12-01 OSTI Identifier: 1121907 Report Number(s): SAND2013-10317J 491314 DOE

  20. Lithium electrodeposition dynamics in aprotic electrolyte observed in situ

    Office of Scientific and Technical Information (OSTI)

    via transmission electron microscopy (Journal Article) | SciTech Connect Journal Article: Lithium electrodeposition dynamics in aprotic electrolyte observed in situ via transmission electron microscopy Citation Details In-Document Search This content will become publicly available on March 18, 2016 Title: Lithium electrodeposition dynamics in aprotic electrolyte observed in situ via transmission electron microscopy Electrodeposited metallic lithium is an ideal negative battery electrode, but

  1. DARK MATTER HALO PROFILES OF MASSIVE CLUSTERS: THEORY VERSUS OBSERVATIONS

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect DARK MATTER HALO PROFILES OF MASSIVE CLUSTERS: THEORY VERSUS OBSERVATIONS Citation Details In-Document Search Title: DARK MATTER HALO PROFILES OF MASSIVE CLUSTERS: THEORY VERSUS OBSERVATIONS Dark-matter-dominated cluster-scale halos act as an important cosmological probe and provide a key testing ground for structure formation theory. Focusing on their mass profiles, we have carried out (gravity-only) simulations of the concordance {Lambda}CDM cosmology,

  2. Dynamics of Molecular Clouds: Observations, Simulations, and NIF

    Office of Scientific and Technical Information (OSTI)

    Experiments (Conference) | SciTech Connect Conference: Dynamics of Molecular Clouds: Observations, Simulations, and NIF Experiments Citation Details In-Document Search Title: Dynamics of Molecular Clouds: Observations, Simulations, and NIF Experiments Authors: Kane, J O ; Martinez, D A ; Pound, M W ; Heeter, R F ; Casner, A ; Mancini, R C Publication Date: 2015-01-16 OSTI Identifier: 1179389 Report Number(s): LLNL-CONF-666498 DOE Contract Number: DE-AC52-07NA27344 Resource Type: Conference

  3. Experimental observation of incoherent-coherent crossover and

    Office of Scientific and Technical Information (OSTI)

    orbital-dependent band renormalization in iron chalcogenide superconductors (Journal Article) | SciTech Connect Experimental observation of incoherent-coherent crossover and orbital-dependent band renormalization in iron chalcogenide superconductors Citation Details In-Document Search This content will become publicly available on December 21, 2016 Title: Experimental observation of incoherent-coherent crossover and orbital-dependent band renormalization in iron chalcogenide superconductors

  4. Feasibility of Observing Small Differences in Friction Mean Effective

    Office of Scientific and Technical Information (OSTI)

    Pressure Between Different Lubricating Oil Formations using Small, Single-Cylinder Motored Engine Rig (Journal Article) | SciTech Connect Journal Article: Feasibility of Observing Small Differences in Friction Mean Effective Pressure Between Different Lubricating Oil Formations using Small, Single-Cylinder Motored Engine Rig Citation Details In-Document Search Title: Feasibility of Observing Small Differences in Friction Mean Effective Pressure Between Different Lubricating Oil Formations

  5. Forecasting neutrino masses from combining KATRIN and the CMB observations:

    Office of Scientific and Technical Information (OSTI)

    Frequentist and Bayesian analyses (Journal Article) | SciTech Connect SciTech Connect Search Results Journal Article: Forecasting neutrino masses from combining KATRIN and the CMB observations: Frequentist and Bayesian analyses Citation Details In-Document Search Title: Forecasting neutrino masses from combining KATRIN and the CMB observations: Frequentist and Bayesian analyses We present a showcase for deriving bounds on the neutrino masses from laboratory experiments and cosmological

  6. The seasonal cycle of satellite chlorophyll fluorescence observations and

    Office of Scientific and Technical Information (OSTI)

    its relationship to vegetation phenology and ecosystem-atmosphere carbon exchange (Journal Article) | SciTech Connect SciTech Connect Search Results Journal Article: The seasonal cycle of satellite chlorophyll fluorescence observations and its relationship to vegetation phenology and ecosystem-atmosphere carbon exchange Citation Details In-Document Search Title: The seasonal cycle of satellite chlorophyll fluorescence observations and its relationship to vegetation phenology and

  7. Augmenting system reliability analyses with observation priors (Conference)

    Office of Scientific and Technical Information (OSTI)

    | SciTech Connect Conference: Augmenting system reliability analyses with observation priors Citation Details In-Document Search Title: Augmenting system reliability analyses with observation priors Occasionally, a system may fail a test without an obvious component being at fault. Instead, experts may know that at least one of a set of components has failed, but there is uncertainty about which members in the set were the actual failures. When no further information is available, this

  8. Common Cyber Security Vulnerabilities Observed in Control System

    Energy Savers [EERE]

    Assessments by the INL NSTB Program | Department of Energy Common Cyber Security Vulnerabilities Observed in Control System Assessments by the INL NSTB Program Common Cyber Security Vulnerabilities Observed in Control System Assessments by the INL NSTB Program This document presents results from 16 control system assessments performed under the NSTB program from 2003 through 2007. Information found in individual stakeholder reports is protected from disclosure. Researchers recognized that

  9. Automated Surface Observing System: Standby Power Options | Department of

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

    Energy Automated Surface Observing System: Standby Power Options Automated Surface Observing System: Standby Power Options This presentation by Anthony Leonardo of the National Weather Service was given at the Fuel Cell Meeting in April 2007. PDF icon fuel_cell_mtng_leonardo.pdf More Documents & Publications Dominion Cove Point LNG, LP - FE Dkt. No 11-128-LNG Order 3331-A: Dominion Cove Point LNG, LP - Dk. No. 11-128-LNG Market Transformation: Fuel Cell Early Adoption (Presentation)

  10. Electronic Structure Changes in Supercapacitor Electrodes Observed In

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

    Operando Electronic Structure Changes in Supercapacitor Electrodes Observed In Operando Electronic Structure Changes in Supercapacitor Electrodes Observed In Operando Print Monday, 09 March 2015 16:58 Profound bias- and time-dependent changes in the electronic structure of graphene-based supercapacitor electrodes are demonstrated under operating conditions via a combination of in operando x-ray spectroscopy and ab initio modeling by J.R.I. Lee and co-workers. The evolution in electronic

  11. First Direct Observation of Carbon Dioxide's Increasing Greenhouse Effect

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

    at Earth's Surface First Direct Observation of Carbon Dioxide's Increasing Greenhouse Effect at Earth's Surface First Direct Observation of Carbon Dioxide's Increasing Greenhouse Effect at Earth's Surface Researchers Link Rising CO₂ Levels from Fossil Fuels to Radiative Forcing February 25, 2015 Contact: Dan Krotz, dakrotz@lbl.gov, 510-486-4019 ARM Alaska Caption: The scientists used incredibly precise spectroscopic instruments at two sites operated by the Department of Energy's

  12. Aided by Simulations, Scientists Observe Atomic Collapse State

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

    Atomic Collapse State Observed Aided by Simulations, Scientists Observe Atomic Collapse State Quantum Mechanics Prediction Confirmed in Graphene Using NERSC's Hopper April 26, 2013 Contact: Linda Vu, lvu@lbl.gov, +1 510 495 2402 Michael Crommie runs the research group that made the discovery. He holds joint appointments with Berkeley Lab and UC Berkeley. (Photo by Roy Kaltschmidt) Scientists have finally confirmed a 70 year-old prediction in quantum mechanics-that electrons in super-heavy atoms

  13. Magnetism and superconductivity observed to exist in harmony

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

    Magnetism and superconductivity exist in harmony Magnetism and superconductivity observed to exist in harmony Physicists have observed, for the first time in a single exotic phase, a situation where magnetism and superconductivity are necessary for each other's existence. August 28, 2008 Los Alamos National Laboratory sits on top of a once-remote mesa in northern New Mexico with the Jemez mountains as a backdrop to research and innovation covering multi-disciplines from bioscience, sustainable

  14. Collaboration yields 'The Right Glasses' for observing mystery behavior

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

    in electrons Observing mystery behavior In electrons Collaboration yields 'The Right Glasses' for observing mystery behavior in electrons The research may lead to a better understanding of superconductors or development of better materials for powering high-speed electronics. December 13, 2007 Los Alamos National Laboratory sits on top of a once-remote mesa in northern New Mexico with the Jemez mountains as a backdrop to research and innovation covering multi-disciplines from bioscience,

  15. Simultaneous observation of nascent plasma and bubble induced by laser

    Office of Scientific and Technical Information (OSTI)

    ablation in water with various pulse durations (Journal Article) | SciTech Connect Simultaneous observation of nascent plasma and bubble induced by laser ablation in water with various pulse durations Citation Details In-Document Search Title: Simultaneous observation of nascent plasma and bubble induced by laser ablation in water with various pulse durations We investigate the effects of pulse duration on the dynamics of the nascent plasma and bubble induced by laser ablation in water. To

  16. Ultrafast observation of shocked states in a precompressed material

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect Ultrafast observation of shocked states in a precompressed material Citation Details In-Document Search Title: Ultrafast observation of shocked states in a precompressed material Authors: Armstrong, M R ; Crowhurst, J C ; Bastea, S ; Zaug, J M Publication Date: 2010-07-08 OSTI Identifier: 1117984 Report Number(s): LLNL-JRNL-442472 DOE Contract Number: W-7405-ENG-48 Resource Type: Journal Article Resource Relation: Journal Name: Journal of Applied Physics,

  17. Enterprise Assessments Operational Awareness Record of Observations of the

    Energy Savers [EERE]

    Design and Modification Progress of the Waste Isolation Pilot Plant Underground Interim Ventilation System and Supplemental Ventilation System November 2015 | Department of Energy of Observations of the Design and Modification Progress of the Waste Isolation Pilot Plant Underground Interim Ventilation System and Supplemental Ventilation System November 2015 Enterprise Assessments Operational Awareness Record of Observations of the Design and Modification Progress of the Waste Isolation Pilot

  18. A cooperative control algorithm for camera based observational systems.

    SciTech Connect (OSTI)

    Young, Joseph G.

    2012-01-01

    Over the last several years, there has been considerable growth in camera based observation systems for a variety of safety, scientific, and recreational applications. In order to improve the effectiveness of these systems, we frequently desire the ability to increase the number of observed objects, but solving this problem is not as simple as adding more cameras. Quite often, there are economic or physical restrictions that prevent us from adding additional cameras to the system. As a result, we require methods that coordinate the tracking of objects between multiple cameras in an optimal way. In order to accomplish this goal, we present a new cooperative control algorithm for a camera based observational system. Specifically, we present a receding horizon control where we model the underlying optimal control problem as a mixed integer linear program. The benefit of this design is that we can coordinate the actions between each camera while simultaneously respecting its kinematics. In addition, we further improve the quality of our solution by coupling our algorithm with a Kalman filter. Through this integration, we not only add a predictive component to our control, but we use the uncertainty estimates provided by the filter to encourage the system to periodically observe any outliers in the observed area. This combined approach allows us to intelligently observe the entire region of interest in an effective and thorough manner.

  19. SIMULATING PROTOSTELLAR JETS SIMULTANEOUSLY AT LAUNCHING AND OBSERVATIONAL SCALES

    SciTech Connect (OSTI)

    Ramsey, Jon P.; Clarke, David A. [Institute for Computational Astrophysics, Department of Astronomy and Physics, Saint Mary's University, Halifax, Nova Scotia B3H 3C3 (Canada)

    2011-02-10

    We present the first 2.5-dimensional magnetohydrodynamic (MHD) simulations of protostellar jets that include both the region in which the jet is launched magnetocentrifugally at scale lengths <0.1 AU and where the propagating jet is observed at scale lengths >10{sup 3} AU. These simulations, performed with the new adaptive mesh refinement MHD code AZEuS, reveal interesting relationships between conditions at the disk surface, such as the magnetic field strength, and direct observables such as proper motion, jet rotation, jet radius, and mass flux. By comparing these quantities with observed values, we present direct numerical evidence that the magnetocentrifugal launching mechanism is capable, by itself, of launching realistic protostellar jets.

  20. Filtering with Marked Point Process Observations via Poisson Chaos Expansion

    SciTech Connect (OSTI)

    Sun Wei; Zeng Yong; Zhang Shu

    2013-06-15

    We study a general filtering problem with marked point process observations. The motivation comes from modeling financial ultra-high frequency data. First, we rigorously derive the unnormalized filtering equation with marked point process observations under mild assumptions, especially relaxing the bounded condition of stochastic intensity. Then, we derive the Poisson chaos expansion for the unnormalized filter. Based on the chaos expansion, we establish the uniqueness of solutions of the unnormalized filtering equation. Moreover, we derive the Poisson chaos expansion for the unnormalized filter density under additional conditions. To explore the computational advantage, we further construct a new consistent recursive numerical scheme based on the truncation of the chaos density expansion for a simple case. The new algorithm divides the computations into those containing solely system coefficients and those including the observations, and assign the former off-line.

  1. Observation of diamond turned OFHC copper using Scanning Tunneling Microscopy

    SciTech Connect (OSTI)

    Grigg, D.A.; Russell, P.E.; Dow, T.A.

    1988-12-01

    Diamond turned OFHC copper samples have been observed within the past few months using the Scanning Tunneling Microscope. Initial results have shown evidence of artifacts which may be used to better understand the diamond turning process. The STM`s high resolution capability and three dimensional data representation allows observation and study of surface features unobtainable with conventional profilometry systems. Also, the STM offers a better quantitative means by which to analyze surface structures than the SEM. This paper discusses findings on several diamond turned OFHC copper samples having different cutting conditions. Each sample has been cross referenced using STM and SEM.

  2. Observation of excited states in /sup 128/Ba

    SciTech Connect (OSTI)

    Zhao Zhi-zheng; Guo Ying-xiang; Pan Zong-you; Xiao Jian-min; Lei Xiang-guo; Liu Hong-ye; Sun Xi-jun

    1987-01-01

    Excited states in /sup 128/Ba have been investigated via the /sup 120/Sn (/sup 12/C, 4n..gamma..) /sup 128/Ba reaction by means of in-beam gamma spectroscopy. A 12/sup +/ state other than the previously reported one is observed according to the properties of the 935.0 keV ..gamma..-ray. It does not belong to the ground-state band. Two new interband transitions, 224.8 keV and 632.7 keV, are observed and assigned to sidefeeding between the negative-parity band and ground-state band.

  3. Observation concerning the process dependence of the Sivers functions

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect Observation concerning the process dependence of the Sivers functions Citation Details In-Document Search Title: Observation concerning the process dependence of the Sivers functions The k{sub perpendicular} moment of a quark's Sivers function is known to be related to the corresponding twist-three quark-gluon correlation function T{sub q,F}(x,x). The two functions have been extracted from data for single-spin asymmetries in semi-inclusive deep-inelastic

  4. Observation of Large Photoacoustic Signal Phase Changes During a Diffusion

    Office of Scientific and Technical Information (OSTI)

    Process (Journal Article) | SciTech Connect Journal Article: Observation of Large Photoacoustic Signal Phase Changes During a Diffusion Process Citation Details In-Document Search Title: Observation of Large Photoacoustic Signal Phase Changes During a Diffusion Process No abstract prepared. Authors: Stanley J. Bajic ; Roger W. Jones ; Jones F. McClelland Publication Date: 2005-09-01 OSTI Identifier: 884839 Report Number(s): IS-J 7054 Journal ID: ISSN 0003-7028; APSPA4; TRN: US200616%%59 DOE

  5. Observation of Magnetoelectric Multiferroicity in a Cubic Perovskite

    Office of Scientific and Technical Information (OSTI)

    System: LaMn 3 Cr 4 O 12 (Journal Article) | SciTech Connect Observation of Magnetoelectric Multiferroicity in a Cubic Perovskite System: LaMn 3 Cr 4 O 12 Citation Details In-Document Search This content will become publicly available on August 17, 2016 Title: Observation of Magnetoelectric Multiferroicity in a Cubic Perovskite System: LaMn 3 Cr 4 O 12 Authors: Wang, Xiao ; Chai, Yisheng ; Zhou, Long ; Cao, Huibo ; Cruz, Clarina-dela ; Yang, Junye ; Dai, Jianhong ; Yin, Yunyu ; Yuan, Zhen ;

  6. LOWER BOUNDS ON INTERGALACTIC MAGNETIC FIELDS FROM SIMULTANEOUSLY OBSERVED

    Office of Scientific and Technical Information (OSTI)

    GeV-TeV LIGHT CURVES OF THE BLAZAR Mrk 501 (Journal Article) | SciTech Connect INTERGALACTIC MAGNETIC FIELDS FROM SIMULTANEOUSLY OBSERVED GeV-TeV LIGHT CURVES OF THE BLAZAR Mrk 501 Citation Details In-Document Search Title: LOWER BOUNDS ON INTERGALACTIC MAGNETIC FIELDS FROM SIMULTANEOUSLY OBSERVED GeV-TeV LIGHT CURVES OF THE BLAZAR Mrk 501 We derive lower bounds on intergalactic magnetic fields (IGMFs) from upper limits on the pair echo emission from the blazar Mrk 501, that is, delayed GeV

  7. Basic visual observation skills training course: Appendix B. Final report

    SciTech Connect (OSTI)

    Toquam, J.L.; Morris, F.A.; Griggs, J.R.

    1995-06-01

    The purpose of the basic visual observation skills course is to help safeguards inspectors evaluate and improve their skills in making observations during inspections and in evaluating and interpreting this information. The first 12 hours of the course provide training in five skill areas: perception and recognition; attention to detail; memory; mental imaging, mapping, and modeling skills; and judgment and decision making. Following this training is an integrating exercise involving a simulated safeguards inspection. This report contains the in-class exercises in the five skill areas; pre- and post-course exercises in closure, hidden figures, map memory, and mental rotations; the final examination; a training evaluation form; and the integrating exercise.

  8. Net Zero Waste - Tools and Technical Support ...and other observations |

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

    Department of Energy Net Zero Waste - Tools and Technical Support ...and other observations Net Zero Waste - Tools and Technical Support ...and other observations Presentation at Waste-to-Energy using Fuel Cells Webinar, July 13, 2011 PDF icon wte_doe-dod_wkshp71311_usarmy.pdf More Documents & Publications DOD -DOE MOU WTE Using Fuel Cells Briefing Waste-to-Energy Technologies and Project Development Report of the DOD-DOE Workshop on Converting Waste to Energy Using Fuel Cells: Workshop

  9. Properties of solar gravity mode signals in total irradiance observations

    SciTech Connect (OSTI)

    Kroll, R.J.; Chen, J.; Hill, H.A.

    1988-01-01

    Further evidence has been found that a significant fraction of the gravity mode power density in the total irradiance observations appears in sidebands of classified eigenfrequencies. These sidebands whose amplitudes vary from year to year are interpreted as harmonics of the rotational frequencies of the nonuniform solar surface. These findings are for non axisymmetric modes and corroborate the findings of Kroll, Hill and Chen for axisymmetric modes. It is demonstrated the the generation of the sidebands lifts the usual restriction on the parity of the eigenfunctions for modes detectable in total irradiance observations. 14 refs.

  10. Observations from The EV Project in Q4 2013

    SciTech Connect (OSTI)

    John Smart

    2014-02-01

    This is a summary report for The EV Project 4th quarter 2013 reports. It describes electric vehicle driver driving and charging behavior observed in Q4. It is the same report as the previously approved/published Q3 2013 report, only the numbers have been updated. It is for public release and does not have limited distribution.

  11. Observable form of pulses emitted from relativistic collapsing objects

    SciTech Connect (OSTI)

    Frolov, Valeri P.; Lee, Hyun Kyu

    2005-02-15

    In this work, we discuss observable characteristics of the radiation emitted from a surface of a collapsing object. We study a simplified model in which a radiation of massless particles has a sharp in time profile, and it happens at the surface at the same moment of comoving time. Since the radiating surface has finite size the observed radiation will occur during some finite time. Its redshift and bending angle are affected by the strong gravitational field. We obtain a simple expression for the observed flux of the radiation as a function of time. To find an explicit expression for the flux we develop an analytical approximation for the bending angle and time delay for null rays emitted by a collapsing surface. In the case of the bending angle this approximation is an improved version of the earlier proposed Beloborodov-Leahy-approximation. For rays emitted at R>2R{sub g} the accuracy of the proposed improved approximations for the bending angle and time delay is of order (or less) than 2%-3%. By using this approximation we obtain an approximate analytical expression for the observed flux and study its properties.

  12. Observable Form of Pulses Emitted From Relativistic Collapsing Objects

    SciTech Connect (OSTI)

    Frolov, V.

    2005-01-28

    In this work, we discuss observable characteristics of the radiation emitted from a surface of a collapsing object. We study a simplified model in which a radiation of massless particles has a sharp in time profile and it happens at the surface at the same moment of comoving time. Since the radiating surface has finite size the observed radiation will occur during some finite time. Its redshift and bending angle are affected by the strong gravitational field. We obtain a simple expression for the observed flux of the radiation as a function of time. To find an explicit expression for the flux we develop an analytical approximation for the bending angle and time delay for null rays emitted by a collapsing surface. In the case of the bending angle this approximation is an improved version of the earlier proposed Beloborodov-Leahy-approximation. For rays emitted at R > 2R{sub g} the accuracy of the proposed improved approximations for the bending angle and time delay is of order (or less) than 2-3%. By using this approximation we obtain an approximate analytical expression for the observed flux and study its properties.

  13. Expanding the Discovery Potential of VERITAS via Moonlight Observations

    SciTech Connect (OSTI)

    Benbow, Wystan R. [PI

    2014-10-27

    This grant partially supported the base research efforts of the Smithsonian Astrophysical Observatory (SAO), Very-High-Energy (VHE; E > 100 GeV) gamma-ray research group from 8/1/09 to 7/31/14. During the project period, the SAO gamma-ray group carried out a wide-range of research efforts, but focused on VHE observations of extragalactic sources with VERITAS. The SAO group led or co-lead nearly all VERITAS extragalactic working groups and the observations addressed themes in Particle Physics and Fundamental Laws, Cosmology, and Black Holes. The primary topics of this research were processes in exotic galaxies, especially active galactic nuclei and starburst galaxies, which have implications for cosmology and Lorentz invariance violation, as well as indirect dark matter detection via VERITAS observations of dwarf spheroidal galaxies. In addition, the SAO group let the development of unique capabilities for VERITAS to observe during all periods of moonlight. Overall, this has increased the VERITAS data yield by 60% and these data are both scientifically useful and regularly published. This grant funded research that led to contributions towards the publication of 51 refereed journal articles during the project period, including several led by, or with significant contributions from, the SAO group.

  14. Direct observation of photoinduced bent nitrosyl excited-state complexes

    SciTech Connect (OSTI)

    Sawyer, Karma R.; Steele, Ryan P.; Glascoe, Elizabeth A.; Cahoon, James F.; Schlegel, Jacob P.; Head-Gordon, Martin; Harris, Charles B.

    2008-06-28

    Ground state structures with side-on nitrosyl ({eta}{sup 2}-NO) and isonitrosyl (ON) ligands have been observed in a variety of transition-metal complexes. In contrast, excited state structures with bent-NO ligands have been proposed for years but never directly observed. Here we use picosecond time-resolved infrared spectroscopy and density functional theory (DFT) modeling to study the photochemistry of Co(CO){sub 3}(NO), a model transition-metal-NO compound. Surprisingly, we have observed no evidence for ON and {eta}{sup 2}-NO structural isomers, but have observed two bent-NO complexes. DFT modeling of the ground and excited state potentials indicates that the bent-NO complexes correspond to triplet excited states. Photolysis of Co(CO){sub 3}(NO) with a 400-nm pump pulse leads to population of a manifold of excited states which decay to form an excited state triplet bent-NO complex within 1 ps. This structure relaxes to the ground triplet state in ca. 350 ps to form a second bent-NO structure.

  15. Observation of objects under intense plasma background illumination

    SciTech Connect (OSTI)

    Buzhinsky, R. O.; Savransky, V. V.; Zemskov, K. I.; Isaev, A. A.; Buzhinsky, O. I.

    2010-12-15

    Experiments on the observation of a brightness-amplified image of an object through a masking arc discharge are presented. The copper-vapor laser active medium was used as an image brightness amplifier. It is shown that the image quality does not worsen under plasma background illumination.

  16. Autonomous observations of the ocean biological carbon pump

    SciTech Connect (OSTI)

    Bishop, James K.B.

    2009-03-01

    Prediction of the substantial biologically mediated carbon flows in a rapidly changing and acidifying ocean requires model simulations informed by observations of key carbon cycle processes on the appropriate space and time scales. From 2000 to 2004, the National Oceanographic Partnership Program (NOPP) supported the development of the first low-cost fully-autonomous ocean profiling Carbon Explorers that demonstrated that year-round real-time observations of particulate organic carbon (POC) concentration and sedimentation could be achieved in the world's ocean. NOPP also initiated the development of a sensor for particulate inorganic carbon (PIC) suitable for operational deployment across all oceanographic platforms. As a result, PIC profile characterization that once required shipboard sample collection and shipboard or shore based laboratory analysis, is now possible to full ocean depth in real time using a 0.2W sensor operating at 24 Hz. NOPP developments further spawned US DOE support to develop the Carbon Flux Explorer, a free-vehicle capable of following hourly variations of particulate inorganic and organic carbon sedimentation from near surface to kilometer depths for seasons to years and capable of relaying contemporaneous observations via satellite. We have demonstrated the feasibility of real time - low cost carbon observations which are of fundamental value to carbon prediction and when further developed, will lead to a fully enhanced global carbon observatory capable of real time assessment of the ocean carbon sink, a needed constraint for assessment of carbon management policies on a global scale.

  17. LES ARM Symbiotic Simulation and Observation (LASSO) Implementation Strategy

    SciTech Connect (OSTI)

    Gustafson Jr., WI; Vogelmann, AM

    2015-09-01

    This document illustrates the design of the Large-Eddy Simulation (LES) ARM Symbiotic Simulation and Observation (LASSO) workflow to provide a routine, high-resolution modeling capability to augment the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility’s high-density observations. LASSO will create a powerful new capability for furthering ARM’s mission to advance understanding of cloud, radiation, aerosol, and land-surface processes. The combined observational and modeling elements will enable a new level of scientific inquiry by connecting processes and context to observations and providing needed statistics for details that cannot be measured. The result will be improved process understanding that facilitates concomitant improvements in climate model parameterizations. The initial LASSO implementation will be for ARM’s Southern Great Plains site in Oklahoma and will focus on shallow convection, which is poorly simulated by climate models due in part to clouds’ typically small spatial scale compared to model grid spacing, and because the convection involves complicated interactions of microphysical and boundary layer processes.

  18. HIGH SPATIAL RESOLUTION OBSERVATIONS OF LOOPS IN THE SOLAR CORONA

    SciTech Connect (OSTI)

    Brooks, David H.; Ugarte-Urra, Ignacio [College of Science, George Mason University, 4400 University Drive, Fairfax, VA 22030 (United States); Warren, Harry P. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); Winebarger, Amy R. [NASA Marshall Space Flight Center, ZP 13, Huntsville, AL 35812 (United States)

    2013-08-01

    Understanding how the solar corona is structured is of fundamental importance to determine how the Sun's upper atmosphere is heated to high temperatures. Recent spectroscopic studies have suggested that an instrument with a spatial resolution of 200 km or better is necessary to resolve coronal loops. The High Resolution Coronal Imager (Hi-C) achieved this performance on a rocket flight in 2012 July. We use Hi-C data to measure the Gaussian widths of 91 loops observed in the solar corona and find a distribution that peaks at about 270 km. We also use Atmospheric Imaging Assembly data for a subset of these loops and find temperature distributions that are generally very narrow. These observations provide further evidence that loops in the solar corona are often structured at a scale of several hundred kilometers, well above the spatial scale of many proposed physical mechanisms.

  19. Observational constraints on late-time {lambda}(t) cosmology

    SciTech Connect (OSTI)

    Carneiro, S.; Pigozzo, C.; Dantas, M. A.; Alcaniz, J. S.

    2008-04-15

    The cosmological constant {lambda}, i.e., the energy density stored in the true vacuum state of all existing fields in the Universe, is the simplest and the most natural possibility to describe the current cosmic acceleration. However, despite its observational successes, such a possibility exacerbates the well-known {lambda} problem, requiring a natural explanation for its small, but nonzero, value. In this paper we study cosmological consequences of a scenario driven by a varying cosmological term, in which the vacuum energy density decays linearly with the Hubble parameter, {lambda}{proportional_to}H. We test the viability of this scenario and study a possible way to distinguish it from the current standard cosmological model by using recent observations of type Ia supernova (Supernova Legacy Survey Collaboration), measurements of the baryonic acoustic oscillation from the Sloan Digital Sky Survey, and the position of the first peak of the cosmic microwave background angular spectrum from the three-year Wilkinson Microwave Anisotropy Probe.

  20. Observation of the Goos-Haenchen Shift with Neutrons

    SciTech Connect (OSTI)

    Haan, Victor-O. de; Plomp, Jeroen; Rekveldt, Theo M.; Kraan, Wicher H.; Well, Ad A. van; Dalgliesh, Robert M.; Langridge, Sean

    2010-01-08

    The Goos-Haenchen effect is a spatial shift along an interface resulting from an interference effect that occurs for total internal reflection. This phenomenon was suggested by Sir Isaac Newton, but it was not until 1947 that the effect was experimentally observed by Goos and Haenchen. We provide the first direct, absolute, experimental determination of the Goos-Haenchen shift for a particle experiencing a potential well as required by quantum mechanics: namely, wave-particle duality. Here, the particle is a spin-polarized neutron reflecting from a film of magnetized material. We detect the effect through a subtle change in polarization of the neutron. Here, we demonstrate, through experiment and theory, that neutrons do exhibit the Goos-Haenchen effect and postulate that the associated time shift should also be observable.

  1. Mass flows in a prominence spine as observed in EUV

    SciTech Connect (OSTI)

    Kucera, T. A.; Gilbert, H. R.

    2014-07-20

    We analyze a quiescent prominence observed by the Solar Dynamics Observatory's Atmospheric Imaging Assembly (AIA) with a focus on mass and energy flux in the spine, measured using Lyman continuum absorption. This is the first time this type of analysis has been applied with an emphasis on individual features and fluxes in a quiescent prominence. The prominence, observed on 2010 September 28, is detectable in most AIA wavebands in absorption and/or emission. Flows along the spine exhibit horizontal bands 5''-10'' wide and kinetic energy fluxes on the order of a few times 10{sup 5} erg s{sup 1}cm{sup 2}, consistent with quiet sun coronal heating estimates. For a discrete moving feature we estimate a mass of a few times 10{sup 11} g. We discuss the implications of our derived properties for a model of prominence dynamics, the thermal non-equilibrium model.

  2. Observation of Stueckelberg oscillations in dipole-dipole interactions

    SciTech Connect (OSTI)

    Ditzhuijzen, C. S. E. van; Tauschinsky, Atreju; Van Linden van den Heuvell, H. B.

    2009-12-15

    We have observed Stueckelberg oscillations in the dipole-dipole interaction between Rydberg atoms with an externally applied radio-frequency field. The oscillating rf field brings the interaction between cold Rydberg atoms in two separated volumes into resonance. We observe multiphoton transitions when varying the amplitude of the rf field and the static electric field offset. The angular momentum states we use show a quadratic Stark shift, which leads to a fundamentally different behavior than linearly shifting states. Both cases are studied theoretically using the Floquet approach and are compared. The amplitude of the sidebands, related to the interaction strength, is given by the Bessel function in the linearly shifting case and by the generalized Bessel function in the quadratically shifting case. The oscillatory behavior of both functions corresponds to Stueckelberg oscillations, an interference effect described by the semiclassical Landau-Zener-Stueckelberg model. The measurements prove coherent dipole-dipole interaction during at least 0.6 mus.

  3. Observation of the Decay B??Ds(*)+K?l????l

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

    del Amo Sanchez, P.; Lees, J. P.; Poireau, V.; Prencipe, E.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Martinelli, M.; Palano, A.; Pappagallo, M.; et al

    2011-07-22

    We report the observation of the decay B??Ds(*)+K?l??l based on 342fb? of data collected at the ?(4S) resonance with the BABAR detector at the PEP-II e?e? storage rings at SLAC. A simultaneous fit to three D+s decay chains is performed to extract the signal yield from measurements of the squared missing mass in the B meson decay. We observe the decay B??Ds(*)+K?l??l with a significance greater than 5 standard deviations (including systematic uncertainties) and measure its branching fraction to be B(B??Ds(*)+K?l??l)=[6.13+1.04-1.03(stat)0.43(syst)0.51(B(Ds))]10??, where the last error reflects the limited knowledge of the Ds branching fractions.

  4. Attosecond Electron Wave-Packet Interference Observed by Transient Absorption

    SciTech Connect (OSTI)

    Holler, M.; Schapper, F.; Gallmann, L.; Keller, U.

    2011-03-25

    We perform attosecond time-resolved transient absorption spectroscopy around the first ionization threshold of helium and observe rapid oscillations of the absorption of the individual harmonics as a function of time delay with respect to a superimposed, moderately strong infrared laser field. The phase relation between the absorption modulation of individual harmonics gives direct evidence for the interference of transiently bound electronic wave packets as the mechanism behind the absorption modulation.

  5. FILAMENTARY STAR FORMATION: OBSERVING THE EVOLUTION TOWARD FLATTENED ENVELOPES

    SciTech Connect (OSTI)

    Lee, Katherine; Looney, Leslie; Johnstone, Doug; Tobin, John E-mail: lwl@illinois.edu E-mail: jtobin@nrao.edu

    2012-12-20

    Filamentary structures are ubiquitous from large-scale molecular clouds (a few parsecs) to small-scale circumstellar envelopes around Class 0 sources ({approx}1000 AU to {approx}0.1 pc). In particular, recent observations with the Herschel Space Observatory emphasize the importance of large-scale filaments (a few parsecs) and star formation. The small-scale flattened envelopes around Class 0 sources are reminiscent of the large-scale filaments. We propose an observationally derived scenario for filamentary star formation that describes the evolution of filaments as part of the process for formation of cores and circumstellar envelopes. If such a scenario is correct, small-scale filamentary structures (0.1 pc in length) with higher densities embedded in starless cores should exist, although to date almost all the interferometers have failed to observe such structures. We perform synthetic observations of filaments at the prestellar stage by modeling the known Class 0 flattened envelope in L1157 using both the Combined Array for Research in Millimeter-wave Astronomy (CARMA) and the Atacama Large Millimeter/Submillimeter Array (ALMA). We show that with reasonable estimates for the column density through the flattened envelope, the CARMA D array at 3 mm wavelengths is not able to detect such filamentary structure, so previous studies would not have detected them. However, the substructures may be detected with the CARMA D+E array at 3 mm and the CARMA E array at 1 mm as a result of more appropriate resolution and sensitivity. ALMA is also capable of detecting the substructures and showing the structures in detail compared to the CARMA results with its unprecedented sensitivity. Such detection will confirm the new proposed paradigm of non-spherical star formation.

  6. Observation of a Macroscopically Quantum-Entangled Insulator

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

    Observation of a Macroscopically Quantum-Entangled Insulator Print It has recently been proposed that insulators with large band gaps and strong spin-orbit coupling can host a new phase of quantum matter called a topological insulator that is characterized by entangled wavefunctions. The proposal has now been realized by an international collaboration led by researchers from Princeton University who studied the electronic structure of insulating alloys of bismuth and antimony by means of

  7. Observation of a Macroscopically Quantum-Entangled Insulator

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

    Observation of a Macroscopically Quantum-Entangled Insulator Print It has recently been proposed that insulators with large band gaps and strong spin-orbit coupling can host a new phase of quantum matter called a topological insulator that is characterized by entangled wavefunctions. The proposal has now been realized by an international collaboration led by researchers from Princeton University who studied the electronic structure of insulating alloys of bismuth and antimony by means of

  8. Observation of a Macroscopically Quantum-Entangled Insulator

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

    Observation of a Macroscopically Quantum-Entangled Insulator Print It has recently been proposed that insulators with large band gaps and strong spin-orbit coupling can host a new phase of quantum matter called a topological insulator that is characterized by entangled wavefunctions. The proposal has now been realized by an international collaboration led by researchers from Princeton University who studied the electronic structure of insulating alloys of bismuth and antimony by means of

  9. Observation of a Macroscopically Quantum-Entangled Insulator

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

    Observation of a Macroscopically Quantum-Entangled Insulator Print It has recently been proposed that insulators with large band gaps and strong spin-orbit coupling can host a new phase of quantum matter called a topological insulator that is characterized by entangled wavefunctions. The proposal has now been realized by an international collaboration led by researchers from Princeton University who studied the electronic structure of insulating alloys of bismuth and antimony by means of

  10. Observation of a Macroscopically Quantum-Entangled Insulator

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

    Observation of a Macroscopically Quantum-Entangled Insulator Print It has recently been proposed that insulators with large band gaps and strong spin-orbit coupling can host a new phase of quantum matter called a topological insulator that is characterized by entangled wavefunctions. The proposal has now been realized by an international collaboration led by researchers from Princeton University who studied the electronic structure of insulating alloys of bismuth and antimony by means of

  11. How does pressure gravitate? Cosmological constant problem confronts observational cosmology

    SciTech Connect (OSTI)

    Narimani, Ali; Scott, Douglas; Afshordi, Niayesh E-mail: nafshordi@pitp.ca

    2014-08-01

    An important and long-standing puzzle in the history of modern physics is the gross inconsistency between theoretical expectations and cosmological observations of the vacuum energy density, by at least 60 orders of magnitude, otherwise known as the cosmological constant problem. A characteristic feature of vacuum energy is that it has a pressure with the same amplitude, but opposite sign to its energy density, while all the precision tests of General Relativity are either in vacuum, or for media with negligible pressure. Therefore, one may wonder whether an anomalous coupling to pressure might be responsible for decoupling vacuum from gravity. We test this possibility in the context of the Gravitational Aether proposal, using current cosmological observations, which probe the gravity of relativistic pressure in the radiation era. Interestingly, we find that the best fit for anomalous pressure coupling is about half-way between General Relativity (GR), and Gravitational Aether (GA), if we include Planck together with WMAP and BICEP2 polarization cosmic microwave background (CMB) observations. Taken at face value, this data combination excludes both GR and GA at around the 3? level. However, including higher resolution CMB observations (''highL'') or baryonic acoustic oscillations (BAO) pushes the best fit closer to GR, excluding the Gravitational Aether solution to the cosmological constant problem at the 4- 5? level. This constraint effectively places a limit on the anomalous coupling to pressure in the parametrized post-Newtonian (PPN) expansion, ?{sub 4}=0.1050.049 (+highL CMB), or ?{sub 4}=0.0660.039 (+BAO). These represent the most precise measurement of this parameter to date, indicating a mild tension with GR (for ?CDM including tensors, with 0?{sub 4}=), and also among different data sets.

  12. Radioactivity in Precipitation: Methods and Observations from Savannah River Site

    Office of Environmental Management (EM)

    Radioactivity in Precipitation: Methods & Observations from Savannah River Site Dennis Jackson P.E. & Timothy Jannik - Savannah River National Laboratory Teresa Eddy - Savannah River Nuclear Solutions 1 H3 Tritium 3.0160492 Presented at the Tritium Focus Group Meeting April 22 - 24, 2014 Aiken, South Carolina 2 Significant Sources of Radionuclides to Atmosphere: Anthropogenic 3 Major Atmospheric Sources in the Unites States: DOE Nuclear Sites (19) 2007 Point Source Emissions: * DOE:

  13. Observation of a Macroscopically Quantum-Entangled Insulator

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

    Observation of a Macroscopically Quantum-Entangled Insulator Print It has recently been proposed that insulators with large band gaps and strong spin-orbit coupling can host a new phase of quantum matter called a topological insulator that is characterized by entangled wavefunctions. The proposal has now been realized by an international collaboration led by researchers from Princeton University who studied the electronic structure of insulating alloys of bismuth and antimony by means of

  14. Observation of a Macroscopically Quantum-Entangled Insulator

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

    Observation of a Macroscopically Quantum-Entangled Insulator Print It has recently been proposed that insulators with large band gaps and strong spin-orbit coupling can host a new phase of quantum matter called a topological insulator that is characterized by entangled wavefunctions. The proposal has now been realized by an international collaboration led by researchers from Princeton University who studied the electronic structure of insulating alloys of bismuth and antimony by means of

  15. Observing Interactions as they happen: Ultrafast Optical Spectroscopies of

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

    Quantum Materials | Stanford Synchrotron Radiation Lightsource Observing Interactions as they happen: Ultrafast Optical Spectroscopies of Quantum Materials Wednesday, January 13, 2016 - 3:00pm SLAC, Redtail Hawk Conference Room 108A Speaker: Giacomo Coslovich, LCLS Program Description Quantum materials exhibit strong and competing interactions between their fundamental constituents, leading to exotic properties such as high-temperature superconductivity and nanoscale charge and spin

  16. NASA Award for Marginal Ice Zone Observations and Process Experiment

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

    (MIZOPEX) Award for Marginal Ice Zone Observations and Process Experiment (MIZOPEX) - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery

  17. ARM - News from the Biomass Burn Observation Project

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

    Project (BBOP)News from the Biomass Burn Observation Project Related Links BBOP Home Outreach News & Press Backgrounder (PDF, 2.1MB) Images ARM flickr site ARM Data Discovery Browse Data Deployment Operations Airborne Measurements Science Plan (PDF, 2.2MB) BBOP wiki Login Required Data Sets Experiment Planning Proposal Abstract and Related Campaigns BBOP Breakout Session, ASR Science Team Meeting, March 2014 BBOP Breakout Session, ASR Science Team Meeting, March 2013 BNL BBOP Website

  18. ARM - LES ARM Symbiotic Simulation and Observation Workflow

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

    ThemesLES ARM Symbiotic Simulation and Observation Workflow LASSO Information LASSO Home LASSO Backgrounder Pilot Phase Begins for Routine Large-Eddy Simulations Pilot Project Timeline Presentations Science LASSO Implementation Strategy Related Information ARM Decadal Vision Archive of LASSO Information e-mail list LASSO Collaboration Letter Contacts William Gustafson, Lead Principal Investigator Andrew Vogelmann, Co-Principal Investigator Hanna Goss, Media Contact LES ARM Symbiotic Simulation

  19. OBSERVATIONS OF THERMAL FLARE PLASMA WITH THE EUV VARIABILITY EXPERIMENT

    SciTech Connect (OSTI)

    Warren, Harry P.; Doschek, George A. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); Mariska, John T. [School of Physics, Astronomy, and Computational Sciences, George Mason University, 4400 University Drive, Fairfax, VA 22030 (United States)

    2013-06-20

    One of the defining characteristics of a solar flare is the impulsive formation of very high temperature plasma. The properties of the thermal emission are not well understood, however, and the analysis of solar flare observations is often predicated on the assumption that the flare plasma is isothermal. The EUV Variability Experiment (EVE) on the Solar Dynamics Observatory provides spectrally resolved observations of emission lines that span a wide range of temperatures (e.g., Fe XV-Fe XXIV) and allow for thermal flare plasma to be studied in detail. In this paper we describe a method for computing the differential emission measure distribution in a flare using EVE observations and apply it to several representative events. We find that in all phases of the flare the differential emission measure distribution is broad. Comparisons of EVE spectra with calculations based on parameters derived from the Geostationary Operational Environmental Satellites soft X-ray fluxes indicate that the isothermal approximation is generally a poor representation of the thermal structure of a flare.

  20. Solar flare impulsive phase emission observed with SDO/EVE

    SciTech Connect (OSTI)

    Kennedy, Michael B.; Milligan, Ryan O.; Mathioudakis, Mihalis; Keenan, Francis P., E-mail: mkennedy29@qub.ac.uk [Astrophysics Research Centre, School of Mathematics and Physics, Queen's University Belfast, University Road, Belfast BT7 1NN (United Kingdom)

    2013-12-10

    Differential emission measures (DEMs) during the impulsive phase of solar flares were constructed using observations from the EUV Variability Experiment (EVE) and the Markov-Chain Monte Carlo method. Emission lines from ions formed over the temperature range log T{sub e} = 5.8-7.2 allow the evolution of the DEM to be studied over a wide temperature range at 10 s cadence. The technique was applied to several M- and X-class flares, where impulsive phase EUV emission is observable in the disk-integrated EVE spectra from emission lines formed up to 3-4 MK and we use spatially unresolved EVE observations to infer the thermal structure of the emitting region. For the nine events studied, the DEMs exhibited a two-component distribution during the impulsive phase, a low-temperature component with peak temperature of 1-2 MK, and a broad high-temperature component from 7 to 30 MK. A bimodal high-temperature component is also found for several events, with peaks at 8 and 25 MK during the impulsive phase. The origin of the emission was verified using Atmospheric Imaging Assembly images to be the flare ribbons and footpoints, indicating that the constructed DEMs represent the spatially average thermal structure of the chromospheric flare emission during the impulsive phase.

  1. First observations of tracking clouds using scanning ARM cloud radars

    SciTech Connect (OSTI)

    Borque, Paloma; Giangrande, Scott; Kollias, Pavlos

    2014-12-01

    Tracking clouds using scanning cloud radars can help to document the temporal evolution of cloud properties well before large drop formation (first echo). These measurements complement cloud and precipitation tracking using geostationary satellites and weather radars. Here, two-dimensional (2-D) Along-Wind Range Height Indicator (AW-RHI) observations of a population of shallow cumuli (with and without precipitation) from the 35-GHz scanning ARM cloud radar (SACR) at the DOE Atmospheric Radiation Measurements (ARM) program Southern Great Plains (SGP) site are presented. Observations from the ARM SGP network of scanning precipitation radars are used to provide the larger scale context of the cloud field and to highlight the advantages of the SACR to detect the numerous, small, non-precipitating cloud elements. A new Cloud Identification and Tracking Algorithm (CITA) is developed to track cloud elements. In CITA, a cloud element is identified as a region having a contiguous set of pixels exceeding a preset reflectivity and size threshold. The high temporal resolution of the SACR 2-D observations (30 sec) allows for an area superposition criteria algorithm to match cloud elements at consecutive times. Following CITA, the temporal evolution of cloud element properties (number, size, and maximum reflectivity) is presented. The vast majority of the designated elements during this cumulus event were short-lived non-precipitating clouds having an apparent life cycle shorter than 15 minutes. The advantages and disadvantages of cloud tracking using an SACR are discussed.

  2. Observational constraints on holographic dark energy with varying gravitational constant

    SciTech Connect (OSTI)

    Lu, Jianbo; Xu, Lixin; Saridakis, Emmanuel N.; Setare, M.R. E-mail: msaridak@phys.uoa.gr E-mail: lxxu@dlut.edu.cn

    2010-03-01

    We use observational data from Type Ia Supernovae (SN), Baryon Acoustic Oscillations (BAO), Cosmic Microwave Background (CMB) and observational Hubble data (OHD), and the Markov Chain Monte Carlo (MCMC) method, to constrain the cosmological scenario of holographic dark energy with varying gravitational constant. We consider both flat and non-flat background geometry, and we present the corresponding constraints and contour-plots of the model parameters. We conclude that the scenario is compatible with observations. In 1? we find ?{sub ?0} = 0.72{sup +0.03}{sub ?0.03}, ?{sub k0} = ?0.0013{sup +0.0130}{sub ?0.0040}, c = 0.80{sup +0.19}{sub ?0.14} and ?{sub G}?G'/G = ?0.0025{sup +0.0080}{sub ?0.0050}, while for the present value of the dark energy equation-of-state parameter we obtain w{sub 0} = ?1.04{sup +0.15}{sub ?0.20}.

  3. Observation of the $\\Xi_b^0$ Baryon

    SciTech Connect (OSTI)

    Aaltonen, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Appel, J.A.; Apresyan, A.; Arisawa, T.; /Waseda U. /Dubna, JINR

    2011-07-01

    The observation of the bottom, strange baryon {Xi}{sup 0}{sub b} through the decay chain {Xi}{sup 0}{sub b} {yields} {Xi}{sup +}{sub c} {pi}{sup -}, where {Xi}{sup +}{sub c} {yields} {Xi}{sup -} {pi}{sup +} {pi}{sup +}, {Xi}{sup -} {yields} {Lambda} {yields} p {pi}{sup -}, is reported using data corresponding to an integrated luminosity of 4.2 ft{sup -1} from p{anti p} collisions at {radical}{ovr s} = 1.96 TeV recorded with the Collider Detector at Fermilab. A signal of 25.3{sup +5.6}{sub -5.4} candidates is observed whose probability of arising from a background fluctuation is 3.6 x 10{sup -12}, corresponding to 6.8 Gaussian standard deviations. The {Xi}{sup 0}{sub b} mass is measured to be 5787.8 {+-} 5.0(stat) {+-} 1.3(syst) MeV/c{sup 2}. In addition, the {Xi}{sup -}{sub b} is observed through the process {Xi}{sup -}{sub b} {yields} {Xi}{sup 0}{sub c} {pi}{sup -}, where {Xi}{sup 0}{sub c} {yields} {Xi}{sup -} {pi}{sup +}, {Xi}{sup -} {yields} {Lambda} {pi}{sup -}, and {Lambda} {yields} p {pi}{sup -}.

  4. Observation of the chiral magnetic effect in ZrTe₅

    SciTech Connect (OSTI)

    Li, Qiang; Kharzeev, Dmitri E.; Zhang, Cheng; Huang, Yuan; Pletikosic, I.; Fedorov, A. V.; Zhong, R. D.; Schneeloch, J. A; Gu, G. D.; Valla, T.

    2015-02-08

    The chiral magnetic effect is the generation of electric current induced by chirality imbalance in the presence of magnetic field. It is a macroscopic manifestation of the quantum anomaly in relativistic field theory of chiral fermions (massless spin 1/2 particles with a definite projection of spin on momentum) – a dramatic phenomenon arising from a collective motion of particles and antiparticles in the Dirac sea. The recent discovery of Dirac semimetals with chiral quasi-particles opens a fascinating possibility to study this phenomenon in condensed matter experiments. Here we report on the first observation of chiral magnetic effect through the measurement of magneto-transport in zirconium pentatelluride, ZrTe₅. Our angle-resolved photoemission spectroscopy experiments show that this material’s electronic structure is consistent with a 3D Dirac semimetal. We observe a large negative magnetoresistance when magnetic field is parallel with the current. The measured quadratic field dependence of the magnetoconductance is a clear indication of the chiral magnetic effect. The observed phenomenon stems from the effective transmutation of Dirac semimetal into a Weyl semimetal induced by the parallel electric and magnetic fields that represent a topologically nontrivial gauge field background.

  5. Off-center observers versus supernovae in inhomogeneous pressure universes

    SciTech Connect (OSTI)

    Balcerzak, Adam; Dabrowski, Mariusz P.; Denkiewicz, Tomasz [Institute of Physics, University of Szczecin, Wielkopolska 15, 70-451 Szczecin (Poland)

    2014-09-10

    Exact luminosity distance and apparent magnitude formulae are applied to the Union2 557 supernovae sample in order to constrain the possible position of an observer outside of the center of symmetry in spherically symmetric inhomogeneous pressure Stephani universes, which are complementary to inhomogeneous density Lematre-Tolman-Bondi (LTB) void models. Two specific models are investigated. The first allows a barotropic equation of state at the center of symmetry without the need to specify a scale factor function (model IIA). The second has no barotropic equation of state at the center, but has an explicit dust-like scale factor evolution (model IIB). It is shown that even at 3? CL, an off-center observer cannot be further than about 4.4 Gpc away from the center of symmetry, which is comparable to the reported size of a void in LTB models with the most likely value of the distance from the center at about 341 Mpc for model IIA and 68 Mpc for model IIB. The off-center observer cannot be farther away from the center than about 577 Mpc for model IIB at 3? CL. It is determined that the best-fit parameters which characterize inhomogeneity are ?{sub inh} = 0.77 (dimensionless: model IIA) and ? = 7.31 10{sup 9} (s km{sup 1}){sup 2/3} Mpc{sup 4/3} (model IIB).

  6. Multi-robot motion control for cooperative observation

    SciTech Connect (OSTI)

    Parker, L.E.

    1997-06-01

    An important issue that arises in the automation of many security, surveillance, and reconnaissance tasks is that of monitoring (or observing) the movements of targets navigating in a bounded area of interest. A key research issue in these problems is that of sensor placement--determining where sensors should be located to maintain the targets in view. In complex applications involving limited-range sensors, the use of multiple sensors dynamically moving over time is required. In this paper, the authors investigate the use of a cooperative team of autonomous sensor-based robots for the observation of multiple moving targets. They focus primarily on developing the distributed control strategies that allow the robot team to attempt to minimize the total time in which targets escape observation by some robot team member in the area of interest. This paper first formalizes the problem and discusses related work. The authors then present a distributed approximate approach to solving this problem that combines low-level multi-robot control with higher-level reasoning control based on the ALLIANCE formalism. They analyze the effectiveness of the approach by comparing it to 3 other feasible algorithms for cooperative control, showing the superiority of the approach for a large class of problems.

  7. HST/COS OBSERVATIONS OF THIRTEEN NEW He II QUASARS

    SciTech Connect (OSTI)

    Syphers, David; Anderson, Scott F.; Zheng Wei; Meiksin, Avery; Schneider, Donald P.; York, Donald G.

    2012-04-15

    The full reionization of intergalactic helium was a major event in the history of the intergalactic medium (IGM), and UV observations of the He II Gunn-Peterson trough allow us to characterize the end of this process at z {approx} 3. Due to intervening hydrogen absorption, quasars allowing such study are rare, with only 33 known in the literature, and most of those are very recent discoveries. We expand on our previous discovery work, and present 13 new He II quasars with redshifts 2.82 < z < 3.77, here selected with {approx}80% efficiency, and including several that are much brighter than the vast majority of those previously known. This is the largest sample of uniformly observed He II quasars covering such a broad redshift range, and they show evidence of IGM opacity increasing with redshift, as expected for the helium reionization epoch. No evidence of He II Ly{alpha} quasar emission is seen in individual or averaged spectra, posing a problem for standard models of the broad-line region. The current rapid advance in the study of He II quasars has been greatly facilitated by the Cosmic Origins Spectrograph on the Hubble Space Telescope, and we discuss the instrumental and other subtleties that must be taken into account in IGM He II observations.

  8. DRAMATIC CHANGE IN JUPITER'S GREAT RED SPOT FROM SPACECRAFT OBSERVATIONS

    SciTech Connect (OSTI)

    Simon, Amy A.; Wong, Michael H.; De Pater, Imke; Rogers, John H.; Orton, Glenn S.; Carlson, Robert W.; Asay-Davis, Xylar; Marcus, Philip S.

    2014-12-20

    Jupiter's Great Red Spot (GRS) is one of its most distinct and enduring features. Since the advent of modern telescopes, keen observers have noted its appearance and documented a change in shape from very oblong to oval, confirmed in measurements from spacecraft data. It currently spans the smallest latitude and longitude size ever recorded. Here we show that this change has been accompanied by an increase in cloud/haze reflectance as sensed in methane gas absorption bands, increased absorption at wavelengths shorter than 500nm, and increased spectral slope between 500 and 630nm. These changes occurred between 2012 and 2014, without a significant change in internal tangential wind speeds; the decreased size results in a 3.2day horizontal cloud circulation period, shorter than previously observed. As the GRS has narrowed in latitude, it interacts less with the jets flanking its north and south edges, perhaps allowing for less cloud mixing and longer UV irradiation of cloud and aerosol particles. Given its long life and observational record, we expect that future modeling of the GRS's changes, in concert with laboratory flow experiments, will drive our understanding of vortex evolution and stability in a confined flow field crucial for comparison with other planetary atmospheres.

  9. OBSERVATION OF MAGNETIC RECONNECTION DRIVEN BY GRANULAR SCALE ADVECTION

    SciTech Connect (OSTI)

    Zeng Zhicheng; Cao Wenda; Ji Haisheng

    2013-06-01

    We report the first evidence of magnetic reconnection driven by advection in a rapidly developing large granule using high spatial resolution observations of a small surge event (base size {approx} 4'' Multiplication-Sign 4'') with the 1.6 m aperture New Solar Telescope at the Big Bear Solar Observatory. The observations were carried out in narrowband (0.5 A) He I 10830 A and broadband (10 A) TiO 7057 A. Since He I 10830 A triplet has a very high excitation level and is optically thin, its filtergrams enable us to investigate the surge from the photosphere through the chromosphere into the lower corona. Simultaneous space data from the Atmospheric Imaging Assembly and Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory were used in the analysis. It is shown that the surge is spatio-temporally associated with magnetic flux emergence in the rapidly developing large granule. During the development of the granule, its advecting flow ({approx}2 km s{sup -1}) squeezed the magnetic flux into an intergranular lane area, where a magnetic flux concentration was formed and the neighboring flux with opposite magnetic polarity was canceled. During the cancellation, the surge was produced as absorption in He I 10830 A filtergrams while simultaneous EUV brightening occurred at its base. The observations clearly indicate evidence of a finest-scale reconnection process driven by the granule's motion.

  10. Observation of incomplete fusion reactions at l < l {sub crit}

    SciTech Connect (OSTI)

    Yadav, Abhishek Sharma, Vijay R. Singh, Devendra P. Unnati,; Singh, B. P.; Prasad, R.; Singh, Pushpendra P.; Bala, Indu; Kumar, R.; Muralithar, S.; Singh, R. P.; Sharma, M. K.

    2014-08-14

    In order to understand the presence of incomplete fusion at low energies i.e. 4-7MeV/nucleon and also to study its dependence on various entrance-channel parameters, the two type of measurements (i) excitation function for {sup 12}C+{sup 159}Tb, and (ii) forward recoil ranges for {sup 12}C+{sup 159}Tb systems have been performed. The experimentally measured excitation functions have been analyzed within the framework of compound nucleus decay using statistical model code PACE4. Analysis of data suggests the production of xn/px)n-channels via complete fusion, as these are found to be well reproduced by PACE4 predictions, while, a significant enhancement in the excitation functions of ?-emitting channels has been observed over the theoretical ones, which has been attributed due to the incomplete fusion processes. Further, the incomplete fusion events observed in case of forward recoil range measurements have been explained on the basis of the breakup fusion model, where these events may be attributed to the fusion of {sup 8}Be and/or {sup 4}He from {sup 12}C projectile to the target nucleus. In the present work, the SUMRULE model calculations are found to highly underestimate the observed incomplete fusion cross-sections which indicate that the l-values lower than l {sub crit} (limit of complete fusion) significantly contribute to the incomplete fusion reactions.

  11. Observation of the chiral magnetic effect in ZrTe₅

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

    Li, Qiang; Kharzeev, Dmitri E.; Zhang, Cheng; Huang, Yuan; Pletikosic, I.; Fedorov, A. V.; Zhong, R. D.; Schneeloch, J. A; Gu, G. D.; Valla, T.

    2015-02-08

    The chiral magnetic effect is the generation of electric current induced by chirality imbalance in the presence of magnetic field. It is a macroscopic manifestation of the quantum anomaly in relativistic field theory of chiral fermions (massless spin 1/2 particles with a definite projection of spin on momentum) – a dramatic phenomenon arising from a collective motion of particles and antiparticles in the Dirac sea. The recent discovery of Dirac semimetals with chiral quasi-particles opens a fascinating possibility to study this phenomenon in condensed matter experiments. Here we report on the first observation of chiral magnetic effect through the measurementmore » of magneto-transport in zirconium pentatelluride, ZrTe₅. Our angle-resolved photoemission spectroscopy experiments show that this material’s electronic structure is consistent with a 3D Dirac semimetal. We observe a large negative magnetoresistance when magnetic field is parallel with the current. The measured quadratic field dependence of the magnetoconductance is a clear indication of the chiral magnetic effect. The observed phenomenon stems from the effective transmutation of Dirac semimetal into a Weyl semimetal induced by the parallel electric and magnetic fields that represent a topologically nontrivial gauge field background.« less

  12. First observations of tracking clouds using scanning ARM cloud radars

    SciTech Connect (OSTI)

    Borque, Paloma; Giangrande, Scott; Kollias, Pavlos

    2014-12-01

    Tracking clouds using scanning cloud radars can help to document the temporal evolution of cloud properties well before large drop formation (‘‘first echo’’). These measurements complement cloud and precipitation tracking using geostationary satellites and weather radars. Here, two-dimensional (2-D) Along-Wind Range Height Indicator (AW-RHI) observations of a population of shallow cumuli (with and without precipitation) from the 35-GHz scanning ARM cloud radar (SACR) at the DOE Atmospheric Radiation Measurements (ARM) program Southern Great Plains (SGP) site are presented. Observations from the ARM SGP network of scanning precipitation radars are used to provide the larger scale context of the cloud field and to highlight the advantages of the SACR to detect the numerous, small, non-precipitating cloud elements. A new Cloud Identification and Tracking Algorithm (CITA) is developed to track cloud elements. In CITA, a cloud element is identified as a region having a contiguous set of pixels exceeding a preset reflectivity and size threshold. The high temporal resolution of the SACR 2-D observations (30 sec) allows for an area superposition criteria algorithm to match cloud elements at consecutive times. Following CITA, the temporal evolution of cloud element properties (number, size, and maximum reflectivity) is presented. The vast majority of the designated elements during this cumulus event were short-lived non-precipitating clouds having an apparent life cycle shorter than 15 minutes. The advantages and disadvantages of cloud tracking using an SACR are discussed.

  13. Insights from modeling and observational evaluation of a precipitating continental cumulus event observed during the MC3E field campaign

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

    Mechem, David B.; Giangrande, Scott E.; Wittman, Carly S.; Borque, Paloma; Toto, Tami; Kollias, Pavlos

    2015-03-13

    A case of shallow cumulus and precipitating cumulus congestus sampled at the Atmospheric Radiation Measurement (ARM) Program Southern Great Plains (SGP) supersite is analyzed using a multi-sensor observational approach and numerical simulation. Observations from a new radar suite surrounding the facility are used to characterize the evolving statistical behavior of the precipitating cloud system. This is accomplished using distributions of different measures of cloud geometry and precipitation properties. Large-eddy simulation (LES) with size-resolved (bin) microphysics is employed to determine the forcings most important in producing the salient aspects of the cloud system captured in the radar observations. Our emphasis ismore » on assessing the importance of time-varying vs. steady-state large-scale forcing on the model's ability to reproduce the evolutionary behavior of the cloud system. Additional consideration is given to how the characteristic spatial scale and homogeneity of the forcing imposed on the simulation influences the evolution of cloud system properties. Results indicate that several new scanning radar estimates such as distributions of cloud top are useful to differentiate the value of time-varying (or at least temporally well-matched) forcing on LES solution fidelity.« less

  14. Ulysses observations of magnetic waves due to newborn interstellar pickup ions. I. New observations and linear analysis

    SciTech Connect (OSTI)

    Cannon, Bradford E.; Smith, Charles W.; Isenberg, Philip A.; Vasquez, Bernard J.; Murphy, Neil; Nuno, Raquel G. E-mail: Charles.Smith@unh.edu E-mail: Bernie.Vasquez@unh.edu E-mail: raquel.nuno@asu.edu

    2014-04-01

    We have examined Ulysses magnetic field data using dynamic spectrogram techniques that compute wave amplitude, polarization, and direction of propagation over a broad range of frequencies and time. Events were identified that showed a strong polarization signature and an enhancement of power above the local proton gyrofrequency. We perform a statistical study of 502 wave events in an effort to determine when, where, and why they are observed. Most notably, we find that waves arising from newborn interstellar pickup ions are relatively rare and difficult to find. The quantities normally employed in theories of wave growth are neutral atom density and quantities related to their ionization and the subsequent dynamics such as wind speed, solar wind flux, and magnetic field orientation. We find the observations of waves to be largely uncorrelated to these quantities except for mean field direction where quasi-radial magnetic fields are favored and solar wind proton flux where wave observations appear to be favored by low flux conditions which runs contrary to theoretical expectations of wave generation. It would appear that an explanation based on source physics and instability growth rates alone is not adequate to account for the times when these waves are seen.

  15. Insights from modeling and observational evaluation of a precipitating continental cumulus event observed during the MC3E field campaign

    SciTech Connect (OSTI)

    Mechem, David B.; Giangrande, Scott E.; Wittman, Carly S.; Borque, Paloma; Toto, Tami; Kollias, Pavlos

    2015-03-13

    A case of shallow cumulus and precipitating cumulus congestus sampled at the Atmospheric Radiation Measurement (ARM) Program Southern Great Plains (SGP) supersite is analyzed using a multi-sensor observational approach and numerical simulation. Observations from a new radar suite surrounding the facility are used to characterize the evolving statistical behavior of the precipitating cloud system. This is accomplished using distributions of different measures of cloud geometry and precipitation properties. Large-eddy simulation (LES) with size-resolved (bin) microphysics is employed to determine the forcings most important in producing the salient aspects of the cloud system captured in the radar observations. Our emphasis is on assessing the importance of time-varying vs. steady-state large-scale forcing on the model's ability to reproduce the evolutionary behavior of the cloud system. Additional consideration is given to how the characteristic spatial scale and homogeneity of the forcing imposed on the simulation influences the evolution of cloud system properties. Results indicate that several new scanning radar estimates such as distributions of cloud top are useful to differentiate the value of time-varying (or at least temporally well-matched) forcing on LES solution fidelity.

  16. Deep z-band observations of the coolest Y dwarf

    SciTech Connect (OSTI)

    Kopytova, Taisiya G.; Crossfield, Ian J. M.; Deacon, Niall R.; Brandner, Wolfgang; Buenzli, Esther; Bayo, Amelia; Schlieder, Joshua E.; Manjavacas, Elena; Kopon, Derek; Biller, Beth A.

    2014-12-10

    WISE J085510.83-071442.5 (hereafter, WISE 0855-07) is the coolest Y dwarf known to date and is located at a distance of 2.31 0.08 pc, giving it the fourth largest parallax of any known star or brown dwarf system. We report deep z-band observations of WISE 0855-07 using FORS2 on UT1/Very Large Telescope. We do not detect any counterpart to WISE 0855-07 in our z-band images and estimate a brightness upper limit of AB mag > 24.8 (F {sub ?} < 0.45 ?Jy) at 910 65 nm with 3? confidence. We combine our z-band upper limit with previous near- and mid-infrared photometry to place constraints on the atmospheric properties of WISE 0855-07 via comparison to models which implement water clouds in the atmospheres of T {sub eff} < 300 K substellar objects. We find that none of the available models that implement water clouds can completely reproduce the observed spectral energy distribution of WISE 0855-07. Every model significantly disagrees with the (3.6 ?m/4.5 ?m) flux ratio and at least one other bandpass. Since methane is predicted to be the dominant absorber at 3-4 ?m, these mismatches might point to an incorrect or incomplete treatment of methane in current models. We conclude that (a) WISE0855-07 has T {sub eff} ? 200-250 K, (b) <80% of its surface is covered by clouds, and (c) deeper observations, and improved models of substellar evolution, atmospheres, clouds, and opacities will be necessary to better characterize this object.

  17. A comparison of observables for solid-solid phase transitions

    SciTech Connect (OSTI)

    Smilowitz, Laura B [Los Alamos National Laboratory; Henson, Bryan F [Los Alamos National Laboratory; Romero, Jerry J [Los Alamos National Laboratory

    2009-01-01

    The study of solid-solid phase transformations is hindered by the difficulty of finding a volumetric probe to use as a progress variable. Solids are typically optically opaque and heterogeneous. Over the past several years, second harmonic generation (SHG) has been used as a kinetic probe for a solid-solid phase transition in which the initial and final phases have different symmetries. Bulk generation of SHG is allowed by symmetry only in noncentrosymmetric crystallographic space groups. For the organic energetic nitramine octahydro-1,3 ,5,7 -tetranitro-1,3 ,5,7 -tatrazocine (HMX), the beta phase is centro symmetric (space group P2{sub 1}/c) and the delta phase iS noncentrosymmetric (space group P6{sub 1}22) making SHG an extremely sensitive, essentially zero background probe of the phase change progress. We have used SHG as a tool to follow the progress of the transformation from beta to delta phase during the solid-solid transformation. However, kinetic models of the transformation derived using different observables from several other groups have differed, showing later onset for the phase change and faster progression to completion. In this work, we have intercompared several techniques to understand these differences. The three techniques discussed are second harmonic generation, Raman spectroscopy, and differential scanning calorimetry (DSC). The progress of the beta to delta phase transition in HMX observed with each of these different probes will be discussed and advantages and disadvantages of each technique described. This paper compares several different observables for use in measuring the kinetics of solid-solid phase transitions. Relative advantages and disadvantages for each technique are described and a direct comparison of results is made for the beta to delta polymorphic phase transition of the energetic nitramine, octahydro-1,3,5,7-tetranitro-1,3,5,7-tatrazocine.

  18. Properties of galactic dark matter: Constraints from astronomical observations

    SciTech Connect (OSTI)

    Burch, B.; Cowsik, R.

    2013-12-10

    The distributions of normal matter and of dark matter in the Galaxy are coupled to each other as they both move in the common gravitational potential. In order to fully exploit this interplay and to derive the various properties of dark matter relevant to their direct and indirect detection, we have comprehensively reviewed the astronomical observations of the spatial and velocity distributions of the components of normal matter. We then postulate that the phase-space distribution of dark matter follows a lowered-isothermal form and self-consistently solve Poisson's equation to construct several models for the spatial and velocity distributions of dark matter. In this paper, we compute the total gravitational potential of the normal and dark matter components and investigate their consistency with current observations of the rotation curve of the Galaxy and of the spatial and velocity distributions of blue horizontal-branch and blue straggler stars. Even with this demand of consistency, a large number of models with a range of parameters characterizing the dark matter distribution remain. We find that the best choice of parameters, within the range of allowed values for the surface density of the disk 55 M {sub ?} pc{sup 2}, are the following: the dark matter density at the Galactic center ?{sub DM,} {sub c} ? 100-250 GeV cm{sup 3}, the local dark matter density ?{sub DM}(R {sub 0}) ? 0.56-0.72 GeV cm{sup 3}, and the rms speed of dark matter particles ?v{sub DM}{sup 2}(R{sub 0})?{sup 1/2}?490??550 km s{sup 1}. We also discuss possible astronomical observations that may further limit the range of the allowed models. The predictions of the allowed models for direct and indirect detection will be discussed separately in a companion paper.

  19. First observations of tracking clouds using scanning ARM cloud radars

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

    Borque, Paloma; Giangrande, Scott; Kollias, Pavlos

    2014-12-01

    Tracking clouds using scanning cloud radars can help to document the temporal evolution of cloud properties well before large drop formation (‘‘first echo’’). These measurements complement cloud and precipitation tracking using geostationary satellites and weather radars. Here, two-dimensional (2-D) Along-Wind Range Height Indicator (AW-RHI) observations of a population of shallow cumuli (with and without precipitation) from the 35-GHz scanning ARM cloud radar (SACR) at the DOE Atmospheric Radiation Measurements (ARM) program Southern Great Plains (SGP) site are presented. Observations from the ARM SGP network of scanning precipitation radars are used to provide the larger scale context of the cloud fieldmore » and to highlight the advantages of the SACR to detect the numerous, small, non-precipitating cloud elements. A new Cloud Identification and Tracking Algorithm (CITA) is developed to track cloud elements. In CITA, a cloud element is identified as a region having a contiguous set of pixels exceeding a preset reflectivity and size threshold. The high temporal resolution of the SACR 2-D observations (30 sec) allows for an area superposition criteria algorithm to match cloud elements at consecutive times. Following CITA, the temporal evolution of cloud element properties (number, size, and maximum reflectivity) is presented. The vast majority of the designated elements during this cumulus event were short-lived non-precipitating clouds having an apparent life cycle shorter than 15 minutes. The advantages and disadvantages of cloud tracking using an SACR are discussed.« less

  20. DETAILED MOLECULAR OBSERVATIONS TOWARD THE DOUBLE HELIX NEBULA

    SciTech Connect (OSTI)

    Torii, K.; Enokiya, R.; Hasegawa, K.; Kudo, N.; Fukui, Y.; Morris, M. R.

    2014-07-01

    The Double Helix Nebula (DHN), located 100 pc above Sgr A* in the Galactic center (GC), is a unique structure whose morphology suggests it is a magnetic feature. Recent molecular observations toward the DHN revealed two candidate molecular counterparts of the DHN at radial velocities of 35 km s{sup 1} and 0 km s{sup 1} and discussed the model in which the DHN has its origin at the circumnuclear disk in the GC. In this paper, new CO observations toward the DHN using the Caltech Submillimeter Observatory and Mopra telescopes are presented. The higher-resolution observations of ?1 pc scale reveal the detailed distributions and kinematics of the two CO counterparts (the 0 km s{sup 1} and 35 km s{sup 1} features) and provide new information on their physical conditions. As a result, we find that the 0 km s{sup 1} feature with a mass of 3.3 10{sup 4} M {sub ?} coincides with the infrared emission of the DHN, indicating clear association with the DHN. The association of the 35 km s{sup 1} feature, with a mass of 0.8 10{sup 4} M {sub ?}, is less clear compared with the 0 km s{sup 1} feature, but the complementary distribution between the molecular gas and the DHN and velocity variation along the DHN support its association with the DHN. The two molecular features are highly excited, as shown by the relatively high CO J = 2-1/J = 1-0 intensity ratios of ?1.0, and have kinetic temperatures of ?30 K, consistent with the typical molecular clouds in the GC.

  1. Observed hemispheric asymmetry in global sea ice changes

    SciTech Connect (OSTI)

    Cavalieri, D.J.; Gloersen, P.; Parkinson, C.L.; Comiso, J.C.; Zwally, H.J.

    1997-11-07

    From November 1978 through December 1996, the areal extent of sea ice decreased by 2.9 {+-} 0.4 percent decade in the Arctic and increased by 1.3 {+-} 0.2 percent per decade in the Antarctic. The observed hemispheric asymmetry in these trends is consistent with a modeled response to a carbon dioxide-induced climate warming. The interannual variations, which are 2.3 percent of the annual mean in the Arctic, with a predominant period of about 5 years, and 3.4 percent of the annual mean in the Antarctic, with a predominant period of about 3 years, are uncorrelated. 29 refs., 2 figs., 1 tab.

  2. The Arctic Lower Troposphere Observed Structure (ALTOS) Campaign

    SciTech Connect (OSTI)

    Verlinde, J

    2010-10-18

    The ALTOS campaign focuses on operating a tethered observing system for routine in situ sampling of low-level (< 2 km) Arctic clouds. It has been a long-term hope to fly tethered systems at Barrow, Alaska, but it is clear that the Federal Aviation Administration (FAA) will not permit in-cloud tether systems at Barrow, even if unmanned aerial vehicle (UAV) operations are allowed in the future. We have provided the scientific rationale for long-term, routine in situ measurements of cloud and aerosol properties in the Arctic. The existing restricted air space at Oliktok offers an opportunity to do so.

  3. RADIO OBSERVATIONS OF HD 80606 NEAR PLANETARY PERIASTRON

    SciTech Connect (OSTI)

    Lazio, T. Joseph W.; Farrell, W. M.; Shankland, P. D.; Blank, D. L.

    2010-12-15

    This paper reports Very Large Array observations at 325 and 1425 MHz ({lambda}90 cm and {lambda}20 cm) during and near the periastron passage of HD 80606b on HJD 2454424.86 (2007 November 20). We obtain flux density limits (3{sigma}) of 1.7 mJy and 48 {mu}Jy at 325 and 1425 MHz, respectively, equivalent to planetary luminosity limits of 2.3 x 10{sup 24} erg s{sup -1} and 2.7 x 10{sup 23} erg s{sup -1}. Unfortunately, these are several orders of magnitude above the nominal Jovian value (at 40 MHz) of 2 x 10{sup 18} erg s{sup -1}. The motivation for these observations was that the planetary magnetospheric emission is driven by a stellar wind-planetary magnetosphere interaction so that the planetary luminosity would be elevated near periastron. We estimate that, near periastron, HD 80606b might be as much as 3000 times more luminous than Jupiter. Recent transit observations of HD 80606b provide reasonably stringent constraints on the planetary mass and radius, and, because of the planet's highly eccentric orbit, its rotation period is likely to be 'pseudo-synchronized' to its orbital period, allowing a robust estimate of the former. Consequently, we are able to make relatively robust estimates of the emission frequency of the planetary magnetospheric emission and find it to be around 60-90 MHz. While this is too low for our reported observations, we compare HD 80606b to other high-eccentricity systems and assess the detection possibilities for both near-term and more distant future systems. Of the known high-eccentricity planets, only HD 80606b is likely to be detectable, as the others (HD 20782B and HD 4113) are both lower mass and longer rotational periods, which imply weaker magnetic field strengths. We find that both the forthcoming 'EVLA low band' system, which will operate as low as 65 MHz, and the Low Frequency Array may be able to improve upon our planetary luminosity limits for HD 80606b, and do so at a more optimum frequency. If the low-frequency component of the Square Kilometre Array (SKA-lo) and a future lunar radio array are able to approach their thermal noise limits, they should be able to detect an HD 80606b-like planet, unless the amount by which the planet's luminosity increases is substantially less than the factor of 3000 that we estimate; for the SKA-lo, which is to be located in the southern hemisphere, future planetary surveys will have to find southern hemisphere equivalents of HD 80606b.

  4. Report on Physics of Channelization: Theory, Experiment, and Observation

    SciTech Connect (OSTI)

    Kudrolli, Arshad

    2014-05-19

    The project involved a study of physical processes that create eroded channel and drainage networks. A particular focus was on how the shape of the channels and the network depended on the nature of the fluid flow. Our approach was to combine theoretical, experimental, and observational studies in close collaboration with Professor Daniel Rothman of the Massachusetts Institute of Technology. Laboratory -scaled experiments were developed and quantitative data on the shape of the pattern and erosion dynamics are obtained with a laser-aided topography technique and fluorescent optical imaging techniques.

  5. ILLUMINATING THE DARKEST GAMMA-RAY BURSTS WITH RADIO OBSERVATIONS

    SciTech Connect (OSTI)

    Zauderer, B. A.; Berger, E.; Margutti, R.; Fong, W.; Laskar, T.; Chornock, R.; Soderberg, A. M. [Department of Astronomy, Harvard University, Cambridge, MA 02138 (United States); Levan, A. J. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Olivares E, F.; Greiner, J. [Max-Planck-Institut fuer extraterrestrische Physik, Giessenbachstrasse, D-85748 Garching (Germany); Perley, D. A.; Horesh, A.; Carpenter, J. [Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA 91225 (United States); Updike, A. C. [Department of Chemistry and Physics, Roger Williams University, Bristol, RI 02809 (United States); Tanvir, N. R. [Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH (United Kingdom); Menten, K. M. [Max-Planck-Institut fuer Radioastronomie, D-53121 Bonn (Germany); Nakar, E. [Department of Astrophysics, Sackler School of Physics and Astronomy, Tel Aviv University, 69978 Tel Aviv (Israel); Chandra, P. [National Centre for Radio Astrophysics, Tata Institute of Fundamental Research, Pune University Campus, Ganeshkhind, Pune 411007 (India); Castro-Tirado, A. J. [Instituto de Astrofisica de Andalucia (IAA-CSIC), P.O. Box 03004, E-18080 Granada (Spain); Bremer, M. [Institut de Radioastronomie Millimetrique, 300 rue de la Piscine, F-38406 Saint Martin d'Heres (France); and others

    2013-04-20

    We present X-ray, optical, near-infrared (IR), and radio observations of gamma-ray bursts (GRBs) 110709B and 111215A, as well as optical and near-IR observations of their host galaxies. The combination of X-ray detections and deep optical/near-IR limits establish both bursts as ''dark''. Sub-arcsecond positions enabled by radio detections lead to robust host galaxy associations, with optical detections that indicate z {approx}< 4 (110709B) and z Almost-Equal-To 1.8-2.9 (111215A). We therefore conclude that both bursts are dark due to substantial rest-frame extinction. Using the radio and X-ray data for each burst we find that GRB 110709B requires A{sub V}{sup host}{approx}>5.3 mag and GRB 111215A requires A{sub V}{sup host}{approx}>8.5 mag (assuming z = 2). These are among the largest extinction values inferred for dark bursts to date. The two bursts also exhibit large neutral hydrogen column densities of N{sub H,{sub int}} {approx}> 10{sup 22} cm{sup -2} (z = 2) as inferred from their X-ray spectra, in agreement with the trend for dark GRBs. Moreover, the inferred values are in agreement with the Galactic A{sub V} -N{sub H} relation, unlike the bulk of the GRB population. Finally, we find that for both bursts the afterglow emission is best explained by a collimated outflow with a total beaming-corrected energy of E{sub {gamma}} + E{sub K} Almost-Equal-To (7-9) Multiplication-Sign 10{sup 51} erg (z = 2) expanding into a wind medium with a high density, M Almost-Equal-To (6-20) Multiplication-Sign 10{sup -5} M{sub Sun} yr{sup -1} (n Almost-Equal-To 100-350 cm{sup -3} at Almost-Equal-To 10{sup 17} cm). While the energy release is typical of long GRBs, the inferred density may be indicative of larger mass-loss rates for GRB progenitors in dusty (and hence metal rich) environments. This study establishes the critical role of radio observations in demonstrating the origin and properties of dark GRBs. Observations with the JVLA and ALMA will provide a sample with sub-arcsecond positions and robust host associations that will help to shed light on obscured star formation and the role of metallicity in GRB progenitors.

  6. Experimental Observation of Quantum Oscillation of Surface Chemical Reactivities

    SciTech Connect (OSTI)

    Ma, X.; Jiang, P.; Qi, Y.; Jia, J.; Yang, Y.; Duan, W.; Li, W. X.; Bao, X.; Zhang, S. B.

    2007-05-29

    Here we present direct observation of a quantum reactivity with respect to the amounts of O2 adsorbed and the rates of surface oxidation as a function of film thickness on ultrathin (2-6 nm) Pb mesas by scanning tunneling microscopy. Simultaneous spectroscopic measurements on the electronic structures reveal a quantum oscillation that originates from quantum well states of the mesas, as a generalization of the Fabry-P{acute e}rot modes of confined electron waves. We expect the quantum reactivity to be a general phenomenon for most ultrathin metal films with broad implications, such as nanostructure tuning of surface reactivities and rational design of heterogeneous catalysts.

  7. LOCALIZED PLASMA DENSITY ENHANCEMENTS OBSERVED IN STEREO COR1

    SciTech Connect (OSTI)

    Jones, Shaela I.; Davila, Joseph M.

    2009-08-20

    Measurements of solar wind speed in the solar corona, where it is primarily accelerated, have proven elusive. One of the more successful attempts has been the tracking of outward-moving density inhomogeneities in white-light coronagraph images. These inhomogeneities, or 'blobs', have been treated as passive tracers of the ambient solar wind. Here we report on the extension of these observations to lower altitudes using the STEREO COR1 coronagraph, and discuss the implications of these measurements for theories about the origin of these features.

  8. Confronting DGP braneworld gravity with cosmico observations after Planck data

    SciTech Connect (OSTI)

    Xu, Lixin

    2014-02-01

    The normal branch of Dvali-Gabadadze-Porrati braneworld gravity with brane tension is confronted by the currently available cosmic observations from the geometrical and dynamical perspectives. On the geometrical side, the type Ia supernova as standard candle, the baryon acoustic oscillation as standard ruler and the cosmic microwave background measurement from the first released 15.5 months data were used to fix the background evolutions. On the dynamical side, the redshift space distortion data will be used to determine the evolution of the matter perturbation. Through a Markov chain Monte Carlo analysis, we found the dimensionless crossover scale ?{sub r{sub c}} = 1/(4H{sup 2}{sub 0}r{sup 2}{sub c}) = 0.00183{sub ?0.00183}{sup +0.000338} in a spatially flat normal branch of Dvali-Gabadadze-Porrati braneworld. This result suggests that the crossover scale r{sub c} should be around 12H{sup ?1}{sub 0} which is consistent with the previous result r{sub c} > 3H{sup ?1}{sub 0} and greater. It also implies that the five-dimensional gravity effect is weak to be observed in H{sup ?1}{sub 0} scale.

  9. Small solar wind transients: Stereo-A observations in 2009

    SciTech Connect (OSTI)

    Yu, W.; Farrugia, C. J.; Galvin, A. B.; Simunac, K. D. C.; Popecki, M. A.; Lugaz, N.; Kilpua, E. K. J.; Moestl, C.; Luhmann, J. G.; Opitz, A.; Sauvaud, J.-A.

    2013-06-13

    Year 2009 was the last year of a long and pronounced solar activity minimum. In this year the solar wind in the inner heliosphere was for 90% of the time slow (< 450 km s{sup -1}) and with a weaker magnetic field strength compared to the previous solar minimum 1995-1996. We choose this year to present the results of a systematic search for small solar wind transients (STs) observed by the STEREO-Ahead (ST-A) probe. The data are from the PLASTIC and IMPACT instrument suites. By 'small' we mean a duration from {approx}1 to 12 hours. The parameters we search for to identify STs are (i) the total field strength, (ii) the rotation of the magnetic field vector, (iii) its smoothness, (iv) proton temperature, (v) proton beta, and (vi) Alfven Mach number. We find 45 examples. The STs have an average duration of {approx}4 hours. Ensemble averages of key quantities are: (i) maximum B = 7.01 nT; (ii) proton {beta}= 0.18; (iii) proton thermal speed = 20.8 km s{sup -1}; and (iv) Alfven Mach number = 6.13. No distinctive feature is found in the pitch angle distributions of suprathermal electrons. Our statistical results are compared with those of STs observed near Earth by Wind during 2009.

  10. Testing coupled dark energy with large scale structure observation

    SciTech Connect (OSTI)

    Yang, Weiqiang; Xu, Lixin, E-mail: d11102004@mail.dlut.edu.cn, E-mail: lxxu@dlut.edu.cn [Institute of Theoretical Physics, School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian, 116024 (China)

    2014-08-01

    The coupling between the dark components provides a new approach to mitigate the coincidence problem of cosmological standard model. In this paper, dark energy is treated as a fluid with a constant equation of state, whose coupling with dark matter is Q-bar =3H?{sub x}?-bar {sub x}. In the frame of dark energy, we derive the evolution equations for the density and velocity perturbations. According to the Markov Chain Monte Carlo method, we constrain the model by currently available cosmic observations which include cosmic microwave background radiation, baryon acoustic oscillation, type Ia supernovae, and f?{sub 8}(z) data points from redshift-space distortion. The results show the interaction rate in ? regions: ?{sub x}=0.00328{sub -0.00328-0.00328-0.00328}{sup +0.000736+0.00549+0.00816}, which means that the recently cosmic observations favor a small interaction rate which is up to the order of 10{sup -2}, meanwhile, the measurement of redshift-space distortion could rule out the large interaction rate in the ? region.

  11. MOCK OBSERVATIONS OF BLUE STRAGGLERS IN GLOBULAR CLUSTER MODELS

    SciTech Connect (OSTI)

    Sills, Alison; Glebbeek, Evert; Chatterjee, Sourav; Rasio, Frederic A. E-mail: e.glebbeek@astro.ru.nl E-mail: rasio@northwestern.edu

    2013-11-10

    We created artificial color-magnitude diagrams of Monte Carlo dynamical models of globular clusters and then used observational methods to determine the number of blue stragglers in those clusters. We compared these blue stragglers to various cluster properties, mimicking work that has been done for blue stragglers in Milky Way globular clusters to determine the dominant formation mechanism(s) of this unusual stellar population. We find that a mass-based prescription for selecting blue stragglers will select approximately twice as many blue stragglers than a selection criterion that was developed for observations of real clusters. However, the two numbers of blue stragglers are well-correlated, so either selection criterion can be used to characterize the blue straggler population of a cluster. We confirm previous results that the simplified prescription for the evolution of a collision or merger product in the BSE code overestimates their lifetimes. We show that our model blue stragglers follow similar trends with cluster properties (core mass, binary fraction, total mass, collision rate) as the true Milky Way blue stragglers as long as we restrict ourselves to model clusters with an initial binary fraction higher than 5%. We also show that, in contrast to earlier work, the number of blue stragglers in the cluster core does have a weak dependence on the collisional parameter ? in both our models and in Milky Way globular clusters.

  12. Difference image analysis of defocused observations with CSTAR

    SciTech Connect (OSTI)

    Oelkers, Ryan J.; Macri, Lucas M.; Wang, Lifan; Ashley, Michael C. B.; Lawrence, Jon S.; Luong-Van, Daniel; Cui, Xiangqun; Gong, Xuefei; Qiang, Liu; Yang, Huigen; Yuan, Xiangyan; Zhou, Xu; Feng, Long-Long; Zhu, Zhenxi; Pennypacker, Carl R.; York, Donald G.

    2015-02-01

    The Chinese Small Telescope ARray carried out high-cadence time-series observations of 27 square degrees centered on the South Celestial Pole during the Antarctic winter seasons of 20082010. Aperture photometry of the 2008 and 2010 i-band images resulted in the discovery of over 200 variable stars. Yearly servicing left the array defocused for the 2009 winter season, during which the system also suffered from intermittent frosting and power failures. Despite these technical issues, nearly 800,000 useful images were obtained using g, r, and clear filters. We developed a combination of difference imaging and aperture photometry to compensate for the highly crowded, blended, and defocused frames. We present details of this approach, which may be useful for the analysis of time-series data from other small-aperture telescopes regardless of their image quality. Using this approach, we were able to recover 68 previously known variables and detected variability in 37 additional objects. We also have determined the observing statistics for Dome A during the 2009 winter season; we find the extinction due to clouds to be less than 0.1 and 0.4 mag for 40% and 63% of the dark time, respectively.

  13. CASSINI VIMS OBSERVATIONS SHOW ETHANE IS PRESENT IN TITAN'S RAINFALL

    SciTech Connect (OSTI)

    Dalba, Paul A.; Buratti, Bonnie J.; Baines, Kevin H.; Sotin, Christophe; Lawrence, Kenneth J.; Brown, Robert H.; Barnes, Jason W.; Clark, Roger N.; Nicholson, Philip D.

    2012-12-20

    Observations obtained over two years by the Cassini Imaging Science Subsystem suggest that rain showers fall on the surface. Using measurements obtained by the Visual Infrared Mapping Spectrometer, we identify the main component of the rain to be ethane, with methane as an additional component. We observe five or six probable rainfall events, at least one of which follows a brief equatorial cloud appearance, suggesting that frequent rainstorms occur on Titan. The rainfall evaporates, sublimates, or infiltrates on timescales of months, and in some cases it is associated with fluvial features but not with their creation or alteration. Thus, Titan exhibits frequent 'gentle rainfall' instead of, or in addition to, more catastrophic events that cut rivers and lay down large fluvial deposits. Freezing rain may also be present, and the standing liquid may exist as puddles interspersed with patches of frost. The extensive dune deposits found in the equatorial regions of Titan imply multi-season arid conditions there, which are consistent with small, but possibly frequent, amounts of rain, in analogy to terrestrial deserts.

  14. An observational study of entrainment rate in deep convection

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

    Guo, Xiaohao; Lu, Chunsong; Zhao, Tianliang; Zhang, Guang Jun; Liu, Yangang

    2015-09-22

    This study estimates entrainment rate and investigates its relationships with cloud properties in 156 deep convective clouds based on in-situ aircraft observations during the TOGA-COARE (Tropical Ocean Global Atmosphere Coupled Ocean Atmosphere Response Experiment) field campaign over the western Pacific. To the authors’ knowledge, this is the first study on the probability density function of entrainment rate, the relationships between entrainment rate and cloud microphysics, and the effects of dry air sources on the calculated entrainment rate in deep convection from an observational perspective. Results show that the probability density function of entrainment rate can be well fitted by lognormal,more » gamma or Weibull distribution, with coefficients of determination being 0.82, 0.85 and 0.80, respectively. Entrainment tends to reduce temperature, water vapor content and moist static energy in cloud due to evaporative cooling and dilution. Inspection of the relationships between entrainment rate and microphysical properties reveals a negative correlation between volume-mean radius and entrainment rate, suggesting the potential dominance of homogeneous mechanism in the clouds examined. The entrainment rate and environmental water vapor content show similar tendencies of variation with the distance of the assumed environmental air to the cloud edges. Their variation tendencies are non-monotonic due to the relatively short distance between adjacent clouds.« less

  15. An observational study of entrainment rate in deep convection

    SciTech Connect (OSTI)

    Guo, Xiaohao; Lu, Chunsong; Zhao, Tianliang; Zhang, Guang Jun; Liu, Yangang

    2015-09-22

    This study estimates entrainment rate and investigates its relationships with cloud properties in 156 deep convective clouds based on in-situ aircraft observations during the TOGA-COARE (Tropical Ocean Global Atmosphere Coupled Ocean Atmosphere Response Experiment) field campaign over the western Pacific. To the authors knowledge, this is the first study on the probability density function of entrainment rate, the relationships between entrainment rate and cloud microphysics, and the effects of dry air sources on the calculated entrainment rate in deep convection from an observational perspective. Results show that the probability density function of entrainment rate can be well fitted by lognormal, gamma or Weibull distribution, with coefficients of determination being 0.82, 0.85 and 0.80, respectively. Entrainment tends to reduce temperature, water vapor content and moist static energy in cloud due to evaporative cooling and dilution. Inspection of the relationships between entrainment rate and microphysical properties reveals a negative correlation between volume-mean radius and entrainment rate, suggesting the potential dominance of homogeneous mechanism in the clouds examined. The entrainment rate and environmental water vapor content show similar tendencies of variation with the distance of the assumed environmental air to the cloud edges. Their variation tendencies are non-monotonic due to the relatively short distance between adjacent clouds.

  16. High-Energy Aspects of Solar Flares: Observations and Models

    SciTech Connect (OSTI)

    Liu, Wei; Guo, Fan

    2015-07-21

    The paper begins by describing the structure of the Sun, with emphasis on the corona. The Sun is a unique plasma laboratory, which can be probed by Sun-grazing comets, and is the driver of space weather. Energization and particle acceleration mechanisms in solar flares is presented; magnetic reconnection is key is understanding stochastic acceleration mechanisms. Then coupling between kinetic and fluid aspects is taken up; the next step is feedback of atmospheric response to the acceleration process – rapid quenching of acceleration. Future challenges include applications of stochastic acceleration to solar energetic particles (SEPs), Fermi γ-rays observations, fast-mode magnetosonic wave trains in a funnel-shaped wave guide associated with flare pulsations, and the new SMEX mission IRIS (Interface Region Imaging Spectrograph),

  17. Parameters of cosmological models and recent astronomical observations

    SciTech Connect (OSTI)

    Sharov, G.S.; Vorontsova, E.G., E-mail: german.sharov@mail.ru, E-mail: elenavor@inbox.ru [Tver state university, 170002, Sadovyj per. 35, Tver (Russian Federation)

    2014-10-01

    For different gravitational models we consider limitations on their parameters coming from recent observational data for type Ia supernovae, baryon acoustic oscillations, and from 34 data points for the Hubble parameter H(z) depending on redshift. We calculate parameters of 3 models describing accelerated expansion of the universe: the ?CDM model, the model with generalized Chaplygin gas (GCG) and the multidimensional model of I. Pahwa, D. Choudhury and T.R. Seshadri. In particular, for the ?CDM model 1? estimates of parameters are: H{sub 0}=70.2620.319 km {sup -1}Mp {sup -1}, ?{sub m}=0.276{sub -0.008}{sup +0.009}, ?{sub ?}=0.7690.029, ?{sub k}=-0.0450.032. The GCG model under restriction 0?? is reduced to the ?CDM model. Predictions of the multidimensional model essentially depend on 3 data points for H(z) with z?2.3.

  18. Thermodynamic properties of mesoscale convective systems observed during BAMEX

    SciTech Connect (OSTI)

    Correia, James; Arritt, R.

    2008-11-01

    Dropsonde observations from the Bow-echo and Mesoscale convective vortex EXperiment (BAMEX) are used to document the spatio-temporal variability of temperature, moisture and wind within mesoscale convective systems (MCSs). Onion type sounding structures are found throughout the stratiform region of MCSs but the temperature and moisture variability is large. Composite soundings were constructed and statistics of thermodynamic variability were generated within each sub-region of the MCS. The calculated air vertical velocity helped identify subsaturated downdrafts. We found that lapse rates within the cold pool varied markedly throughout the MCS. Layered wet bulb potential temperature profiles seem to indicate that air within the lowest several km comes from a variety of source regions. We also found that lapse rate transitions across the 0 C level were more common than isothermal, melting layers. We discuss the implications these findings have and how they can be used to validate future high resolution numerical simulations of MCSs.

  19. Observation of the sigma_b baryons at CDF

    SciTech Connect (OSTI)

    Pursley, Jennifer M.; /Johns Hopkins U.

    2007-03-01

    We present a measurement of four new bottom baryons in proton-antiproton collisions with a center of mass energy of 1.96 TeV. Using 1.1 fb{sup -1} of data collected by the CDF II detector, we observe four {Lambda}{sup 0}{sub b}{pi}{+-} resonances in the fully reconstructed decay mode {Lambda}{sup 0}{sub b} {yields} {Lambda}{sup +}{sub c}{pi}{sup -}, where {Lambda}{sup +}{sub c} {yields} pK{sup -}{pi}{sup +}. The probability for the background to produce a similar or larger signal is less than 8.3 x 10{sup -8}, corresponding to a significance of greater than 5.2 {sigma}. We interpret these baryons as the {Sigma}{sub b}{sup (*){+-}} baryons.

  20. Waveguides for performing spectroscopy with confined effective observation volumes

    DOE Patents [OSTI]

    Levene, Michael J.; Korlach, Jonas; Turner, Stephen W.; Craighead, Harold G.; Webb, Watt W.

    2006-03-14

    The present invention is directed to a method and an apparatus for analysis of an analyte. The method involves providing a zero-mode waveguide which includes a cladding surrounding a core where the cladding is configured to preclude propagation of electromagnetic energy of a frequency less than a cutoff frequency longitudinally through the core of the zero-mode waveguide. The analyte is positioned in the core of the zero-mode waveguide and is then subjected, in the core of the zero-mode waveguide, to activating electromagnetic radiation of a frequency less than the cut-off frequency under conditions effective to permit analysis of the analyte in an effective observation volume which is more compact than if the analysis were carried out in the absence of the zero-mode waveguide.

  1. Beam-beam observations in the Relativistic Heavy Ion Collider

    SciTech Connect (OSTI)

    Luo, Y.; Fischer, W.; White, S.

    2015-06-24

    The Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory has been operating since 2000. Over the past decade, thanks to the continuously increased bunch intensity and reduced β*s at the interaction points, the maximum peak luminosity in the polarized proton operation has been increased by more than two orders of magnitude. In this article, we first present the beam-beam observations in the previous RHIC polarized proton runs. Then we analyze the mechanisms for the beam loss and emittance growth in the presence of beam-beam interaction. The operational challenges and limitations imposed by beam-beam interaction and their remedies are also presented. In the end, we briefly introduce head-on beam-beam compensation with electron lenses in RHIC.

  2. Observations of underdense plasma lens focusing of relativistic electron beams

    SciTech Connect (OSTI)

    Thompson, M.C.; Badakov, H.; Rosenzweig, J.B.; Travish, G.; Fliller, R.; Kazakevich, G.M.; Piot, P.; Santucci, J.; Li, J.; Tikhoplav, R.; /Rochester U.

    2007-06-01

    Focusing of a 15 MeV, 19 nC electron bunch by an underdense plasma lens operated just beyond the threshold of the underdense condition has been demonstrated in experiments at the Fermilab NICADD Photoinjector Laboratory (FNPL). The strong 1.9 cm focal-length plasma-lens focused both transverse directions simultaneously and reduced the minimum area of the beam spot by a factor of 23. Analysis of the beam-envelope evolution observed near the beam waist shows that the spherical aberrations of this underdense lens are lower than those of an overdense plasma lens, as predicted by theory. Correlations between the beam charge and the properties of the beam focus corroborate this conclusion.

  3. OBSERVATIONAL CONSTRAINTS ON METHANOL PRODUCTION IN INTERSTELLAR AND PREPLANETARY ICES

    SciTech Connect (OSTI)

    Whittet, D. C. B.; Cook, A. M.; Herbst, Eric; Chiar, J. E.; Shenoy, S. S.

    2011-11-20

    Methanol (CH{sub 3}OH) is thought to be an important link in the chain of chemical evolution that leads from simple diatomic interstellar molecules to complex organic species in protoplanetary disks that may be delivered to the surfaces of Earthlike planets. Previous research has shown that CH{sub 3}OH forms in the interstellar medium predominantly on the surfaces of dust grains. To enhance our understanding of the conditions that lead to its efficient production, we assemble a homogenized catalog of published detections and limiting values in interstellar and preplanetary ices for both CH{sub 3}OH and the other commonly observed C- and O-bearing species, H{sub 2}O, CO, and CO{sub 2}. We use this catalog to investigate the abundance of ice-phase CH{sub 3}OH in environments ranging from dense molecular clouds to circumstellar envelopes around newly born stars of low and high mass. Results show that CH{sub 3}OH production arises during the CO freezeout phase of ice-mantle growth in the clouds, after an ice layer rich in H{sub 2}O and CO{sub 2} is already in place on the dust, in agreement with current astrochemical models. The abundance of solid-phase CH{sub 3}OH in this environment is sufficient to account for observed gas-phase abundances when the ices are subsequently desorbed in the vicinity of embedded stars. CH{sub 3}OH concentrations in the ices toward embedded stars show order-of-magnitude object-to-object variations, even in a sample restricted to stars of low mass associated with ices lacking evidence of thermal processing. We hypothesize that the efficiency of CH{sub 3}OH production in dense cores and protostellar envelopes is mediated by the degree of prior CO depletion.

  4. Observation of $t$-channel electroweak top quark production

    SciTech Connect (OSTI)

    Triplett, Nathan; /Iowa State U.

    2011-04-01

    The top quark is the heaviest known fundamental particle, with a mass of 172.0{sub -1.3}{sup +0.9}GeV. This is nearly twice the mass of the second heaviest known particle, the Z boson, and roughly the mass of a gold atom. Because of its unusually large mass, studying the top quark may provide insight into the Higgs mechanism and other beyond the standard model physics. Only two accelerators in the world are powerful enough to produce top quarks. The Tevatron, which first accelerated protons in 1983, has produced almost 400,000 top quarks, roughly half at each of its two detectors: DO and CDF. The LHC is a much newer accelerator which currently has accumulated about 0.5% as much data as the Tevatron. However, when running at full luminosity, the LHC is capable of producing a top quark about once every second and will quickly surpass the Tevatron as the leading producer of top quarks. This analysis uses data from the D0 detector at the Tevatron, which are described in chapter 3. Top quarks are produced most often in pairs of top and anti-top quarks through an interaction of the strong force. This production mode was first observed in 1995 at the Tevatron. However, top quarks can also be produced though an electroweak interaction, which produces just one top quark. This production mode was first observed at the Tevatron in 2008. Single top quark production can occur in different channels. In this analysis, a measurement of the cross section of the t-channel production mode is performed. This measurement uses 5.4 fb{sup -1} of data and uses the technique of boosted decision trees in order to separate signal from background events. The t-channel cross section is measured to be: {sigma}(p{bar p} {yields} tqb + X) = 3.03{sub -0.66}{sup +0.78}pb (0.0.1). Additional cross section measurements were also performed for the s-channel as well as the s + t-channel. The measurement of each one of these three cross sections was repeated three times using different techniques, and all three methods were combined into a 'super-method' which achieves the best performance. The details of these additional measurements are shown in appendix A.

  5. Observation of an ''ABC'' Effect in Proton-Proton Collisions

    SciTech Connect (OSTI)

    Dymov, S.; Yaschenko, S.; Hartmann, M.; Kacharava, A.; Nekipelov, M.; Ohm, H.; Rathmann, F.; Stroeher, H.; Khoukaz, A.; Mielke, M.; Komarov, V.; Kulikov, A.; Kurbatov, V.; Uzikov, Yu.; Zalikhanov, B.; Kulessa, P.; Macharashvili, G.; Merzliakov, S.; Tsirkov, D.; Mikirtychiants, S.

    2009-05-15

    The cross section for inclusive multipion production in the pp{yields}ppX reaction was measured at COSY-ANKE at four beam energies, 0.8, 1.1, 1.4, and 2.0 GeV, for low excitation energy in the final pp system, such that the diproton quasiparticle is in the {sup 1}S{sub 0} state. At the three higher energies, the missing-mass M{sub X} spectra show a strong enhancement at low M{sub X}, corresponding to an Abashian-Booth-Crowe effect that moves steadily to larger values as the energy is increased. Despite the missing-mass structure looking very different at 0.8 GeV, the variation with M{sub X} and beam energy are consistent with two-pion production being mediated through the excitation of two {delta}(1232) isobars, coupled to S and D states of the initial pp system. There is no sign of any resonancelike structure in the energy dependence of the type recently observed for the pn{yields}d{pi}{sup 0}{pi}{sup 0} total cross section.

  6. Real-time observation of epitaxial graphene domain reorientation

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

    Thuermer, Konrad; Foster, Michael E.; Bartelt, Norman Charles; Rogge, Paul C.; Lawrence Berkeley National Lab.; McCarty, Kevin F.; Dubon, Oscar D.; Lawrence Berkeley National Lab.; Bartelt, Norman C.

    2015-04-20

    Graphene films grown by vapour deposition tend to be polycrystalline due to the nucleation and growth of islands with different in-plane orientations. Here, using low-energy electron microscopy, we find that micron-sized graphene islands on Ir(111) rotate to a preferred orientation during thermal annealing. We observe three alignment mechanisms: the simultaneous growth of aligned domains and dissolution of rotated domains, that is, ‘ripening’; domain boundary motion within islands; and continuous lattice rotation of entire domains. By measuring the relative growth velocity of domains during ripening, we estimate that the driving force for alignment is on the order of 0.1 meV permore » C atom and increases with rotation angle. A simple model of the orientation-dependent energy associated with the moiré corrugation of the graphene sheet due to local variations in the graphene–substrate interaction reproduces the results. This study suggests new strategies for improving the van der Waals epitaxy of 2D materials.« less

  7. APOSTLE: 11 TRANSIT OBSERVATIONS OF TrES-3b

    SciTech Connect (OSTI)

    Kundurthy, P.; Becker, A. C.; Agol, E.; Barnes, R.; Williams, B.

    2013-02-10

    The Apache Point Survey of Transit Lightcurves of Exoplanets (APOSTLE) observed 11 transits of TrES-3b over two years in order to constrain system parameters and look for transit timing and depth variations. We describe an updated analysis protocol for APOSTLE data, including the reduction pipeline, transit model, and Markov Chain Monte Carlo analyzer. Our estimates of the system parameters for TrES-3b are consistent with previous estimates to within the 2{sigma} confidence level. We improved the errors (by 10%-30%) on system parameters such as the orbital inclination (i {sub orb}), impact parameter (b), and stellar density ({rho}{sub *}) compared to previous measurements. The near-grazing nature of the system, and incomplete sampling of some transits, limited our ability to place reliable uncertainties on individual transit depths and hence we do not report strong evidence for variability. Our analysis of the transit timing data shows no evidence for transit timing variations and our timing measurements are able to rule out super-Earth and gas giant companions in low-order mean motion resonance with TrES-3b.

  8. The observational status of Galileon gravity after Planck

    SciTech Connect (OSTI)

    Barreira, Alexandre; Li, Baojiu; Baugh, Carlton M.; Pascoli, Silvia E-mail: baojiu.li@durham.ac.uk E-mail: silvia.pascoli@durham.ac.uk

    2014-08-01

    We use the latest CMB data from Planck, together with BAO measurements, to constrain the full parameter space of Galileon gravity. We constrain separately the three main branches of the theory known as the Cubic, Quartic and Quintic models, and find that all yield a very good fit to these data. Unlike in ?CDM, the Galileon model constraints are compatible with local determinations of the Hubble parameter and predict nonzero neutrino masses at over 5? significance. We also identify that the low l part of the CMB lensing spectrum may be able to distinguish between ?CDM and Galileon models. In the Cubic model, the lensing potential deepens at late times on sub-horizon scales, which is at odds with the current observational suggestion of a positive ISW effect. Compared to ?CDM, the Quartic and Quintic models predict less ISW power in the low l region of the CMB temperature spectrum, and as such are slightly preferred by the Planck data. We illustrate that residual local modifications to gravity in the Quartic and Quintic models may render the Cubic model as the only branch of Galileon gravity that passes Solar System tests.

  9. Observational tests of non-adiabatic Chaplygin gas

    SciTech Connect (OSTI)

    Carneiro, S.; Pigozzo, C. E-mail: cpigozzo@ufba.br

    2014-10-01

    In a previous paper [1] it was shown that any dark sector model can be mapped into a non-adiabatic fluid formed by two interacting components, one with zero pressure and the other with equation-of-state parameter ?=-1. It was also shown that the latter does not cluster and, hence, the former is identified as the observed clustering matter. This guarantees that the dark matter power spectrum does not suffer from oscillations or instabilities. It applies in particular to the generalised Chaplygin gas, which was shown to be equivalent to interacting models at both background and perturbation levels. In the present paper we test the non-adiabatic Chaplygin gas against the Hubble diagram of type Ia supernovae, the position of the first acoustic peak in the anisotropy spectrum of the cosmic microwave background and the linear power spectrum of large scale structures. We consider two different compilations of SNe Ia, namely the Constitution and SDSS samples, both calibrated with the MLCS2k2 fitter, and for the power spectrum we use the 2dFGRS catalogue. The model parameters to be adjusted are the present Hubble parameter, the present matter density and the Chaplygin gas parameter ?. The joint analysis best fit gives ??-0.5, which corresponds to a constant-rate energy flux from dark energy to dark matter, with the dark energy density decaying linearly with the Hubble parameter. The ?CDM model, equivalent to ?=0, stands outside the 3? confidence interval.

  10. Far-Infrared Spectral Observations of the Galaxy by COBE

    SciTech Connect (OSTI)

    Reach, W.T.; Dwek, E.; Fixsen, D.J.; Hewagama, T.; Mather, J.C.; Shafer, R.A.; Banday, A.J.; Bennett, C.L.; Cheng, E.S.; Eplee Jr., R.E.,; Leisawi tz, D.; Lubin, P.M.; Read, S.M.; Rosen, L.P.; Shuman, F.G.D.; Smoot, G.F.; Sodroski, T.J.; Wright, E.L.

    1994-10-27

    We derive Galactic continuum spectra from 5-96 cm(-1) fromCOBE/FIRAS observations. The spectra are dominated by warm dust emission,which may be fitted with a single temperature in the range 16-21 K (fornu(2) emissivity) along each line of sight. Dust heated by the attenuatedradiation field in molecular clouds gives rise tointermediate-temperature (10-14 K) emission in the inner Galaxy only. Awidespread, very cold component (4-7 K) with optical depth that isspatially correlated with the warm component is also detected. The coldcomponent is unlikely to be due to very cold dust shielded from starlightbecause it is present at high latitude. We consider hypotheses that thecold component is due to enhanced submillimeter emissivity of the dustthat gives rise to the warm component, or that it may be due to verysmall, large, or fractal particles. Lack of substantial power above theemission from warm dust places strong constraints on the amount of coldgas in the Galaxy. The microwave sky brightness due to interstellar dustis dominated by the cold component, and its angular variation could limitour ability to discern primordial fluctuations in the cosmic microwavebackground radiation.

  11. Observation manipulator bell proves worth in Transmediterranean pipeline construction

    SciTech Connect (OSTI)

    Lewis, R.E.

    1981-10-26

    In constructing the trans-Mediterranean undersea pipeline between Tunisia and Sicily, Perry Oceanographics used a manned, tethered vehicle called an observation manipulator bell (OMB), which has proven itself in deepwater pipelaying operations. The OMB carries a crew of two inside a pressure hull with an internal diameter of 76 in. Its overall diameter is 102 in. and it weighs 17,500 lb. The vehicle has two 5-hp port- and starboard-mounted electric thrusters. Its vertical position can be controlled by either the bell operator using a clump-weight haul-down winch or the surface operator with the umbilical winch. The OMB is fitted with video cameras and voice communication. The vehicle has reached depths of 3000 ft within 30 min with only a 10-ft overshoot. The OMB's single and/or dual manipulator-arm systems can operate its onboard impact wrenches, cut-off saws, water jets, and cable cutters. In addition, the manipulator claws can operate valve wheels and levers, attach anodes, and connect of disconnect cables and hydraulic systems. The versatility of the OMB was demonstrated recently when the vehicle rescued a PC-1602 submarine that had become entangled at 1740 ft.

  12. License renewal demonstration program: NRC observations and lessons learned

    SciTech Connect (OSTI)

    Prato, R.J.; Kuo, P.T.; Newberry, S.F.

    1996-12-01

    This report summarizes the Nuclear Regulatory Commission staff`s observations and lessons learned from the five License Renewal Demonstration Program (LRDP) site visits performed by the staff from March 25, 1996, through August 16, 1996. The LRDP was a Nuclear Energy Institute (NEI) program intended to assess the effectiveness of the guidance provided by NEI 95-10, Revision 0, {open_quotes}Industry Guideline for Implementing the Requirements of 10 CFR Part 54 - The License Renewal Rule,{close_quotes} to implement the requirements of Title 10 of the Code of Federal Regulations, Part 54 (10 CFR Part 54), {open_quotes}Requirements for Renewal of Operating Licenses for Nuclear Power Plants.{close_quotes} In general, NEI 95-10 appeared to contain the basic guidance needed for scoping, screening, identifying aging effects, developing aging management programs, and performing time-limited aging analyses. However, inconsistent implementation of this guidance in some areas was an indication that clarification of existing guidance and/or the inclusion-of some new guidance may be needed for applicants to develop a license renewal program that is consistent with the intent of the rule.

  13. Biomass Burning Observation Project (BBOP) Final Campaign Report

    SciTech Connect (OSTI)

    Kleinman, LI; Sedlacek, A. J.

    2016-01-01

    The Biomass Burning Observation Project (BBOP) was conducted to obtain a better understanding of how aerosols generated from biomass fires affect the atmosphere and climate. It is estimated that 40% of carbonaceous aerosol produced originates from biomass burning—enough to affect regional and global climate. Several biomass-burning studies have focused on tropical climates; however, few campaigns have been conducted within the United States, where millions of acres are burned each year, trending to higher values and greater climate impacts because of droughts in the West. Using the Atmospheric Radiation Measurement (ARM) Aerial Facility (AAF), the BBOP deployed the Gulfstream-1 (G-1) aircraft over smoke plumes from active wildfire and agricultural burns to help identify the impact of these events and how impacts evolve with time. BBOP was one of very few studies that targeted the near-field time evolution of aerosols and aimed to obtain a process-level understanding of the large changes that occur within a few hours of atmospheric processing.

  14. Experimental Observation of Nuclear Reactions in Palladium and Uranium

    SciTech Connect (OSTI)

    J. Dufour; D. Murat; X. Dufour; J. Foos

    2001-11-12

    By submitting various metals (Pd, U) containing hydrogen (from 2000 to 700 000 atoms of hydrogen for 1 000 000 atoms of the host metal) to the combined action of electrical currents and magnetic fields, we have observed a sizeable exothermal effect (from 0.1 to 8 W for 500 mg of metal used). This effect is beyond experimental errors, the energy output being typically 130 to 250{percent} of the energy input and not of chemical origin (exothermal effect in the range of 7000 MJ/mol of metal in the case of palladium and of 60 MJ/mol in the case of uranium). New chemical species also appear in the processes metals. It has been shown by a QED calculation that resonances of long lifetime (s), nuclear dimensions (fm), and low energy of formation (eV) could exist. This concept seems to look like the 'shrunken hydrogen atoms' proposed by various authors. It is indeed very different in two ways (a) being a metastable state, it needs energy to be formed (a few eV) and reverts to normal hydrogen after a few seconds, liberating back its energy of formation (it is thus not the source of the energy observed); (b) its formation can be described as the electron spin/proton nuclear spin interaction becoming first order in the lattice environment (whereas it is third order in a normal hydrogen atom). Moreover, we consider that the hydrex cannot yield a neutron because this reaction is strongly endothermic. To explain our results, we put forward the following working hypothesis: In a metal lattice and under proper conditions, the formation of such resonances (metastable state) could be favored. We propose to call them HYDREX, and we assume that they are actually formed in cold fusion (CF) and low-energy nuclear reaction (LENR) experiments. Once formed, a number of HYDREX could gather around a nucleus of the lattice to form a cluster of nuclear size and of very long life time compared to nuclear time (10{sup -22} s). In this cluster, nuclear rearrangements could take place, yielding mainly {sup 4}He, nuclei of atomic masses smaller than that of the host metal and small amounts of {sup 3}He and tritium. Because this nuclear rearrangement is a many-body reaction, the products formed should be stable products in their ground states, most of the reaction energy being carried away as kinetic energy by the alpha particles formed. The HYDREX hypothesis describes CF and LENR as fundamentally the same phenomenon, which we propose to call NUCLEAR CATALYSIS. Depending on the conditions of a CF or LENR experiment, the products formed may look very different, but the initial step is always the synthesis of HYDREX. When this synthesis is mastered, CF and LENR experiments should become fully reproducible.

  15. Lightning and radar observations of hurricane Rita landfall

    SciTech Connect (OSTI)

    Henderson, Bradley G; Suszcynsky, David M; Hamlin, Timothy E; Jeffery, C A; Wiens, Kyle C; Orville, R E

    2009-01-01

    Los Alamos National Laboratory (LANL) owns and operates an array of Very-Low Frequency (VLF) sensors that measure the Radio-Frequency (RF) waveforms emitted by Cloud-to-Ground (CG) and InCloud (IC) lightning. This array, the Los Alamos Sferic Array (LASA), has approximately 15 sensors concentrated in the Great Plains and Florida, which detect electric field changes in a bandwidth from 200 Hz to 500 kHz (Smith et al., 2002). Recently, LANL has begun development of a new dual-band RF sensor array that includes the Very-High Frequency (VHF) band as well as the VLF. Whereas VLF lightning emissions can be used to deduce physical parameters such as lightning type and peak current, VHF emissions can be used to perform precise 3d mapping of individual radiation sources, which can number in the thousands for a typical CG flash. These new dual-band sensors will be used to monitor lightning activity in hurricanes in an effort to better predict intensification cycles. Although the new LANL dual-band array is not yet operational, we have begun initial work utilizing both VLF and VHF lightning data to monitor hurricane evolution. In this paper, we present the temporal evolution of Rita's landfall using VLF and VHF lightning data, and also WSR-88D radar. At landfall, Rita's northern eyewall experienced strong updrafts and significant lightning activity that appear to mark a transition between oceanic hurricane dynamics and continental thunderstorm dynamics. In section 2, we give a brief overview of Hurricane Rita, including its development as a hurricane and its lightning history. In the following section, we present WSR-88D data of Rita's landfall, including reflectivity images and temporal variation. In section 4, we present both VHF and VLF lightning data, overplotted on radar reflectivity images. Finally, we discuss our observations, including a comparison to previous studies and a brief conclusion.

  16. Observation of dynamic water microadsorption on Au surface

    SciTech Connect (OSTI)

    Huang, Xiaokang, E-mail: xiaokang.huang@tqs.com; Gupta, Gaurav; Gao, Weixiang; Tran, Van; Nguyen, Bang; McCormick, Eric; Cui, Yongjie; Yang, Yinbao; Hall, Craig; Isom, Harold [TriQuint Semiconductor, Inc., 500 W Renner Road, Richardson, Texas 75080 (United States)

    2014-05-15

    Experimental and theoretical research on water wettability, adsorption, and condensation on solid surfaces has been ongoing for many decades because of the availability of new materials, new detection and measurement techniques, novel applications, and different scales of dimensions. Au is a metal of special interest because it is chemically inert, has a high surface energy, is highly conductive, and has a relatively high melting point. It has wide applications in semiconductor integrated circuitry, microelectromechanical systems, microfluidics, biochips, jewelry, coinage, and even dental restoration. Therefore, its surface condition, wettability, wear resistance, lubrication, and friction attract a lot of attention from both scientists and engineers. In this paper, the authors experimentally investigated Au{sub 2}O{sub 3} growth, wettability, roughness, and adsorption utilizing atomic force microscopy, scanning electron microscopy, reflectance spectrometry, and contact angle measurement. Samples were made using a GaAs substrate. Utilizing a super-hydrophilic Au surface and the proper surface conditions of the surrounding GaAs, dynamic microadsorption of water on the Au surface was observed in a clean room environment. The Au surface area can be as small as 12??m{sup 2}. The adsorbed water was collected by the GaAs groove structure and then redistributed around the structure. A model was developed to qualitatively describe the dynamic microadsorption process. The effective adsorption rate was estimated by modeling and experimental data. Devices for moisture collection and a liquid channel can be made by properly arranging the wettabilities or contact angles of different materials. These novel devices will be very useful in microfluid applications or biochips.

  17. Electromagnetic waves near the proton cyclotron frequency: Stereo observations

    SciTech Connect (OSTI)

    Jian, L. K.; Wei, H. Y.; Russell, C. T.; Luhmann, J. G.; Klecker, B.; Omidi, N.; Isenberg, P. A.; Goldstein, M. L.; Figueroa-Vias, A.; Blanco-Cano, X.

    2014-05-10

    Transverse, near-circularly polarized, parallel-propagating electromagnetic waves around the proton cyclotron frequency were found sporadically in the solar wind throughout the inner heliosphere. They could play an important role in heating and accelerating the solar wind. These low-frequency waves (LFWs) are intermittent but often occur in prolonged bursts lasting over 10 minutes, named 'LFW storms'. Through a comprehensive survey of them from Solar Terrestrial Relations Observatory A using dynamic spectral wave analysis, we have identified 241 LFW storms in 2008, present 0.9% of the time. They are left-hand (LH) or right-hand (RH) polarized in the spacecraft frame with similar characteristics, probably due to Doppler shift of the same type of waves or waves of intrinsically different polarities. In rare cases, the opposite polarities are observed closely in time or even simultaneously. Having ruled out interplanetary coronal mass ejections, shocks, energetic particles, comets, planets, and interstellar ions as LFW sources, we discuss the remaining generation scenarios: LH ion cyclotron instability driven by greater perpendicular temperature than parallel temperature or by ring-beam distribution, and RH ion fire hose instability driven by inverse temperature anisotropy or by cool ion beams. The investigation of solar wind conditions is compromised by the bias of the one-dimensional Maxwellian fit used for plasma data calibration. However, the LFW storms are preferentially detected in rarefaction regions following fast winds and when the magnetic field is radial. This preference may be related to the ion cyclotron anisotropy instability in fast wind and the minimum in damping along the radial field.

  18. Meteorological Observations for Renewable Energy Applications at Site 300

    SciTech Connect (OSTI)

    Wharton, S; Alai, M; Myers, K

    2011-10-26

    In early October 2010, two Laser and Detection Ranging (LIDAR) units (LIDAR-96 and LIDAR-97), a 3 m tall flux tower, and a 3 m tall meteorological tower were installed in the northern section of Site 300 (Figure 1) as a first step in development of a renewable energy testbed facility. This section of the SMS project is aimed at supporting that effort with continuous maintenance of atmospheric monitoring instruments capable of measuring vertical profiles of wind speed and wind direction at heights encountered by future wind power turbines. In addition, fluxes of energy are monitored to estimate atmospheric mixing and its effects on wind flow properties at turbine rotor disk heights. Together, these measurements are critical for providing an accurate wind resource characterization and for validating LLNL atmospheric prediction codes for future renewable energy projects at Site 300. Accurate, high-resolution meteorological measurements of wind flow in the planetary boundary layer (PBL) and surface-atmosphere energy exchange are required for understanding the properties and quality of available wind power at Site 300. Wind speeds at heights found in a typical wind turbine rotor disk ({approx} 40-140 m) are driven by the synergistic impacts of atmospheric stability, orography, and land-surface characteristics on the mean wind flow in the PBL and related turbulence structures. This section of the report details the maintenance and labor required in FY11 to optimize the meteorological instruments and ensure high accuracy of their measurements. A detailed look at the observations from FY11 is also presented. This portion of the project met the following milestones: Milestone 1: successful maintenance and data collection of LIDAR and flux tower instruments; Milestone 2: successful installation of solar power for the LIDAR units; and Milestone 3: successful implementation of remote data transmission for the LIDAR units.

  19. Uncovering the single top: observation of electroweak top quark production

    SciTech Connect (OSTI)

    Benitez, Jorge Armando; /Michigan State U.

    2009-08-01

    The top quark is generally produced in quark and anti-quark pairs. However, the Standard Model also predicts the production of only one top quark which is mediated by the electroweak interaction, known as 'Single Top'. Single Top quark production is important because it provides a unique and direct way to measure the CKM matrix element V{sub tb}, and can be used to explore physics possibilities beyond the Standard Model predictions. This dissertation presents the results of the observation of Single Top using 2.3 fb{sup -1} of Data collected with the D0 detector at the Fermilab Tevatron collider. The analysis includes the Single Top muon+jets and electron+jets final states and employs Boosted Decision Tress as a method to separate the signal from the background. The resulting Single Top cross section measurement is: (1) {sigma}(p{bar p} {yields} tb + X, tqb + X) = 3.74{sub -0.74}{sup +0.95} pb, where the errors include both statistical and systematic uncertainties. The probability to measure a cross section at this value or higher in the absence of signal is p = 1.9 x 10{sup -6}. This corresponds to a standard deviation Gaussian equivalence of 4.6. When combining this result with two other analysis methods, the resulting cross section measurement is: (2) {sigma}(p{bar p} {yields} tb + X, tqb + X) = 3.94 {+-} 0.88 pb, and the corresponding measurement significance is 5.0 standard deviations.

  20. Observing Signatures of Cosmic Rays Using High-Energy Gamma-Ray...

    Office of Scientific and Technical Information (OSTI)

    Conference: Observing Signatures of Cosmic Rays Using High-Energy Gamma-Ray Telescopes Citation Details In-Document Search Title: Observing Signatures of Cosmic Rays Using...

  1. 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 sufficient to excite exciton XB. The dynamics of trion T2 formation are found to correlate with the disappearance of the bleach of XB exciton, which indicates the involvement of holes participating in the bleach dynamics of exciton XB. Static electrical-doping photoabsorption measurements confirm the presence of an induced absorption peak similar to that of T2. Since the proposed trion formation process here involves exciton dissociation through hole-trapping by defects in the 2D crystal or substrate, this discovery highlights the strong role that defects have in defining the optical and electrical properties of 2D metal chalcogenides, which is relevant to a broad spectrum of basic science and technology applications.« less

  2. 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 XBs 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 ?pump < 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 ?pump > 2.4 eV, which is just sufficient to excite exciton XB. The dynamics of trion T2 formation are found to correlate with the disappearance of the bleach of XB exciton, which indicates the involvement of holes participating in the bleach dynamics of exciton XB. Static electrical-doping photoabsorption measurements confirm the presence of an induced absorption peak similar to that of T2. Since the proposed trion formation process here involves exciton dissociation through hole-trapping by defects in the 2D crystal or substrate, this discovery highlights the strong role that defects have in defining the optical and electrical properties of 2D metal chalcogenides, which is relevant to a broad spectrum of basic science and technology applications.

  3. Round Robin Testing of Commercial Hydrogen Sensor Performance--Observations and Results: Preprint

    SciTech Connect (OSTI)

    Buttner, W.; Burgess, R.; Rivkin, C.; Post, M.; Boon-Bret, L.; Black, G.; Harskamp, F.; Moretto, P.

    2010-10-01

    This paper presented observations and results from round robin testing of commercial hydrogen sensor performance.

  4. Collaborative Research: Separating Forced and Unforced Decadal Predictability in Models and Observations

    SciTech Connect (OSTI)

    DelSole, Timothy

    2015-11-30

    Collaborative Research: Separating Forced and Unforced Decadal Predictability in Models and Observations

  5. Intensive Observation

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

    of the clouds and the overall cloud field over a triangular study area with sides roughly six miles long. The southwest corner of the triangular experiment area will be at the...

  6. Observation of Supernova Remnant IC443 with the Fermi Large Area...

    Office of Scientific and Technical Information (OSTI)

    Observation of Supernova Remnant IC443 with the Fermi Large Area Telescope Citation Details In-Document Search Title: Observation of Supernova Remnant IC443 with the Fermi Large...

  7. Ulysses observations of magnetic waves due to newborn interstellar pickup ions. II. Application of turbulence concepts to limiting wave energy and observability

    SciTech Connect (OSTI)

    Cannon, Bradford E.; Smith, Charles W.; Isenberg, Philip A.; Vasquez, Bernard J.; Joyce, Colin J.; Murphy, Neil; Nuno, Raquel G. E-mail: Charles.Smith@unh.edu E-mail: Bernie.Vasquez@unh.edu E-mail: Neil.Murphy@jpl.nasa.gov

    2014-06-01

    The low-frequency magnetic waves that arise from the isotropization of newborn interstellar pickup ions (PUIs) are reasonably well described by linear and quasi-linear kinetic theory in so far as those theories predict the wave frequency and polarization in the spacecraft frame. Those theories fail to describe the scarce observability of the waves. Quasilinear theory predicts that the wave power should accumulate over long periods of time as the relatively weak kinetic instability slowly adds power to the observed spectrum. At the same time it has been argued that the same wave energy must serve as a secondary source of thermal ion heating in the outer heliosphere once the initial turbulence is depleted. To the extent that turbulent transport of the wave energy acts against the spectrally confined accumulation of wave energy, turbulence should be a limiting factor in observability. We argue that turbulence does limit the observability of the waves and we use turbulence theory to predict the observed wave energy. We compare this prediction against a database of 502 wave observations attributed to newborn interstellar PUIs observed by the Ulysses spacecraft.

  8. ARM - Field Campaign - Observations and Modeling of the Green Ocean Amazon

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

    (GOAMAZON) Amazon (GOAMAZON) Campaign Links GOAMAZON Website ARM Manacapuru Deployment Page ARM Data Discovery Browse Data Related Campaigns Observations and Modeling of the Green Ocean Amazon - Hi-Vol Filter Sampling 2015.03.13, de Mello Dias Machado, AMF Observations and Modeling of the Green Ocean Amazon: LIDAR Comparison 2014.10.05, Barbosa, AMF Observations and Modeling of the Green Ocean Amazon: Oxidation Flow Reactor 2 2014.08.15, Palm, AMF Observations and Modeling of the Green Ocean

  9. Observable Proxies For 26 Al Enhancement (Journal Article) | SciTech

    Office of Scientific and Technical Information (OSTI)

    Connect Observable Proxies For 26 Al Enhancement Citation Details In-Document Search Title: Observable Proxies For 26 Al Enhancement We consider the cospatial production of elements in supernova explosions to find observationally detectable proxies for enhancement of {sup 26}Al in supernova ejecta and stellar systems. Using four progenitors we explore a range of 1D explosions at different energies and an asymmetric 3D explosion. We find that the most reliable indicator of the presence of

  10. Pervasive faint Fe XIX emission from a solar active region observed with

    Office of Scientific and Technical Information (OSTI)

    EUNIS-13: Evidence for nanoflare heating (Journal Article) | SciTech Connect Pervasive faint Fe XIX emission from a solar active region observed with EUNIS-13: Evidence for nanoflare heating Citation Details In-Document Search Title: Pervasive faint Fe XIX emission from a solar active region observed with EUNIS-13: Evidence for nanoflare heating We present spatially resolved EUV spectroscopic measurements of pervasive, faint Fe XIX 592.2 Å line emission in an active region observed during

  11. CHARA/MIRC observations of two M supergiants in Perseus OB1: Temperature,

    Office of Scientific and Technical Information (OSTI)

    bayesian modeling, and compressed sensing imaging (Journal Article) | SciTech Connect CHARA/MIRC observations of two M supergiants in Perseus OB1: Temperature, bayesian modeling, and compressed sensing imaging Citation Details In-Document Search Title: CHARA/MIRC observations of two M supergiants in Perseus OB1: Temperature, bayesian modeling, and compressed sensing imaging Two red supergiants (RSGs) of the Per OB1 association, RS Per and T Per, have been observed in the H band using the

  12. Stellar and gaseous nuclear disks observed in nearby (U)LIRGs (Journal

    Office of Scientific and Technical Information (OSTI)

    Article) | SciTech Connect Stellar and gaseous nuclear disks observed in nearby (U)LIRGs Citation Details In-Document Search Title: Stellar and gaseous nuclear disks observed in nearby (U)LIRGs We present near-infrared integral field spectroscopy of the central kiloparsec of 17 nearby luminous and ultra-luminous infrared galaxies undergoing major mergers. These observations were taken with OSIRIS assisted by the Keck I and II Adaptive Optics systems, providing spatial resolutions of a few

  13. OSCILLATORY BEHAVIOR IN THE QUIET SUN OBSERVED WITH THE NEW SOLAR TELESCOPE

    SciTech Connect (OSTI)

    Andic, A.; Goode, P. R.; Cao, W.; Yurchyshyn, V.; Abramenko, V.; Chae, J.; Ahn, K.

    2010-07-10

    Surface photometry of the quiet Sun has achieved an angular resolution of 0.''1 with the New Solar Telescope at Big Bear Solar Observatory, revealing that a disproportionate fraction of the oscillatory events appear above observed bright point-like structures. During the tracking of these structures, we noted that the more powerful oscillatory events are cospatial with them, indicating that observed flux tubes may be the source of many observed oscillatory events.

  14. Observation of Rayleigh-Taylor-instability evolution in a plasma with magnetic and viscous effects

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

    Adams, Colin S.; Moser, Auna L.; Hsu, Scott C.

    2015-11-06

    We present time-resolved observations of Rayleigh-Taylor-instability (RTI) evolution at the interface between an unmagnetized plasma jet colliding with a stagnated, magnetized plasma. The observed instability growth time (~10μs) is consistent with the estimated linear RTI growth rate calculated using experimentally inferred values of density (~1014cm–3) and deceleration (~109 m/s2). The observed mode wavelength (≳1 cm) nearly doubles within a linear growth time. Furthermore, theoretical estimates of magnetic and viscous stabilization and idealized magnetohydrodynamic simulations including a physical viscosity model both suggest that the observed instability evolution is subject to magnetic and/or viscous effects.

  15. Seismic observations in the geodynamic proving at the Sayano-Shushenskaya HPP

    SciTech Connect (OSTI)

    Dergachev, A. A.; Yemanov, A. F.; Toloshinov, A. V.

    2007-09-15

    Results of seismic observations of the dam indicated that its resonance vibrations do not correspond to the basic operating frequency of the generating sets.

  16. Observation of Ion-Cyclotron-Frequency Mode-Conversion Flow Drive...

    Office of Scientific and Technical Information (OSTI)

    Title: Observation of Ion-Cyclotron-Frequency Mode-Conversion Flow Drive in Tokamak Plasmas Strong toroidal flow (Vsub phi) and poloidal flow (Vsub theta) have been ...

  17. An Observed Signature of Aerosol Effect on Cloud Droplet Radii from a

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

    Decade of Observations at a Mid-Continental Site An Observed Signature of Aerosol Effect on Cloud Droplet Radii from a Decade of Observations at a Mid-Continental Site Min, Qilong State University of New York at Albany Duan, Minzheng State University of New York at Albany Harrison, Lee State University of New York Joseph, Everette Howard University Category: Aerosols Continuing observations of aerosol and cloud optical property have been made using MFRSR and MWR at the ARM SGP site since

  18. Observables can be tailored to change the entanglement of any pure state

    SciTech Connect (OSTI)

    Harshman, N. L.; Ranade, Kedar S.

    2011-07-15

    We show that, for a finite-dimensional Hilbert space, there exist observables that induce a tensor product structure such that the entanglement properties of any pure state can be tailored. In particular, we provide an explicit, finite method for constructing observables in an unstructured d-dimensional system so that an arbitrary known pure state has any Schmidt decomposition with respect to an induced bipartite tensor product structure. In effect, this article demonstrates that, in a finite-dimensional Hilbert space, entanglement properties can always be shifted from the state to the observables and all pure states are equivalent as entanglement resources in the ideal case of complete control of observables.

  19. CHARA/MIRC observations of two M supergiants in Perseus OB1:...

    Office of Scientific and Technical Information (OSTI)

    Temperature, bayesian modeling, and compressed sensing imaging Citation Details In-Document Search Title: CHARAMIRC observations of two M supergiants in Perseus OB1: Temperature, ...

  20. ASYMMETRY IN THE OBSERVED METAL-RICH EJECTA OF THE GALACTIC TYPE IA

    Office of Scientific and Technical Information (OSTI)

    SUPERNOVA REMNANT G299.2-2.9 (Journal Article) | SciTech Connect ASYMMETRY IN THE OBSERVED METAL-RICH EJECTA OF THE GALACTIC TYPE IA SUPERNOVA REMNANT G299.2-2.9 Citation Details In-Document Search Title: ASYMMETRY IN THE OBSERVED METAL-RICH EJECTA OF THE GALACTIC TYPE IA SUPERNOVA REMNANT G299.2-2.9 We have performed a deep Chandra observation of the Galactic Type Ia supernova remnant G299.2-2.9. Here we report the initial results from our imaging and spectral analysis. The observed

  1. MHK ISDB/Instruments/TRDI Ocean Observer ADCP | Open Energy Informatio...

    Open Energy Info (EERE)

    TRDI Ocean Observer ADCP < MHK ISDB Jump to: navigation, search MHK Instrumentation & Sensor Database Menu Home Search Add Instrument Add Sensor Add Company Community FAQ Help...

  2. Key Neutrino behavior observed at Daya Bay (The College of William and

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

    Mary) | Jefferson Lab www.wm.edu/news/stories/2012/key-neutrino-behavior-observed-at-daya-bay-123.php Submitted: Thursday, March 8, 2012

  3. Optical Observations of Gamma-Ray Bursts: Connections to GeV...

    Office of Scientific and Technical Information (OSTI)

    Observations of Gamma-Ray Bursts: Connections to GeVTeV Jets Vestrand, W. Thomas Los Alamos National Laboratory Astronomy & Astrophysics(79) Astronomy and Astrophysics Astronomy...

  4. CX-011436: Categorical Exclusion Determination

    Broader source: Energy.gov [DOE]

    Development of Methods to Prohibit and Remediate Loss of Annular Isolation in Shale Gas Wells CX(s) Applied: A9, A11, Specific Category: field observation of drilling operations Date: 11/21/2013 Location(s): Arkansas Offices(s): National Energy Technology Laboratory

  5. CX-100401 Categorical Exclusion Determination

    Broader source: Energy.gov [DOE]

    Assimilation of Wave Imaging Radar Observations for Real-time Wave-by-Wave Forecasting Award Number: DE- EE-0006789 CX(s) Applied: A9, B3.1 Water Power Program Date: 11/09/2015 Location(s): Oregon Office(s): Golden Field Office

  6. CX-012702: Categorical Exclusion Determination

    Broader source: Energy.gov [DOE]

    An Investigation To Establish Multiphysical Property Dataset of Nuclear Materials Based on In-Situ Observations and Measurements, NEAMS: Nuclear Energy Advanced Modeling and Simulation – Purdue University CX(s) Applied: B3.6Date: 41862 Location(s): IndianaOffices(s): Nuclear Energy

  7. CX-012686: Categorical Exclusion Determination

    Broader source: Energy.gov [DOE]

    An Investigation To Establish Multiphysical Property Dataset of Nuclear Materials Based on In- Situ Observations and Measurements, NEAMS: Nuclear Energy Advanced Modeling and Simulation – Purdue University CX(s) Applied: B3.6Date: 41862 Location(s): IndianaOffices(s): Nuclear Energy

  8. Evaluating Clouds, Aerosols, and their Interactions in Three Global Climate Models using COSP and Satellite Observations

    SciTech Connect (OSTI)

    Ban-Weiss, George; Jin, Ling; Bauer, S.; Bennartz, Ralph; Liu, Xiaohong; Zhang, Kai; Ming, Yi; Guo, Huan; Jiang, Jonathan

    2014-09-23

    Accurately representing aerosol-cloud interactions in global climate models is challenging. As parameterizations evolve, it is important to evaluate their performance with appropriate use of observations. In this work we compare aerosols, clouds, and their interactions in three climate models (AM3, CAM5, ModelE) to MODIS satellite observations. Modeled cloud properties were diagnosed using the CFMIP Observations Simulator Package (COSP). Cloud droplet number concentrations (N) were derived using the same algorithm for both satellite-simulated model values and observations. We find that aerosol optical depth tau simulated by models is similar to observations. For N, AM3 and CAM5 capture the observed spatial pattern of higher values in near-coast versus remote ocean regions, though modeled values in general are higher than observed. In contrast, ModelE simulates lower N in most near-coast versus remote regions. Aerosol- cloud interactions were computed as the sensitivity of N to tau for marine liquid clouds off the coasts of South Africa and Eastern Asia where aerosol pollution varies in time. AM3 and CAM5 are in most cases more sensitive than observations, while the sensitivity for ModelE is statistically insignificant. This widely used sensitivity could be subject to misinterpretation due to the confounding influence of meteorology on both aerosols and clouds. A simple framework for assessing the N tau sensitivity at constant meteorology illustrates that observed sensitivity can change from positive to statistically insignificant when including the confounding influence of relative humidity. Satellite simulated values of N were compared to standard model output and found to be higher with a bias of 83 cm-3.

  9. Measurement of the Kerr spin parameter by observation of a compact object's shadow

    SciTech Connect (OSTI)

    Hioki, Kenta; Maeda, Kei-ichi

    2009-07-15

    A black hole casts a shadow as an optical appearance because of its strong gravitational field. We study how to determine the spin parameter and the inclination angle by observing the apparent shape of the shadow, which is distorted mainly by those two parameters. Defining some observables characterizing the apparent shape (its radius and distortion parameter), we find that the spin parameter and inclination angle of a Kerr black hole can be determined by the observation. This technique is also extended to the case of a Kerr naked singularity.

  10. Observation of Ion-Cyclotron-Frequency Mode-Conversion Flow Drive in

    Office of Scientific and Technical Information (OSTI)

    Tokamak Plasmas (Journal Article) | SciTech Connect Observation of Ion-Cyclotron-Frequency Mode-Conversion Flow Drive in Tokamak Plasmas Citation Details In-Document Search Title: Observation of Ion-Cyclotron-Frequency Mode-Conversion Flow Drive in Tokamak Plasmas Strong toroidal flow (V{sub {phi}}) and poloidal flow (V{sub {theta}}) have been observed in D-{sup 3}He plasmas with ion cyclotron range of frequencies (ICRF) mode-conversion (MC) heating on the Alcator C-Mod tokamak. The toroidal

  11. Hubble space telescope and ground-based observations of the type Iax

    Office of Scientific and Technical Information (OSTI)

    supernovae SN 2005hk and SN 2008A (Journal Article) | SciTech Connect Hubble space telescope and ground-based observations of the type Iax supernovae SN 2005hk and SN 2008A Citation Details In-Document Search Title: Hubble space telescope and ground-based observations of the type Iax supernovae SN 2005hk and SN 2008A We present Hubble Space Telescope (HST) and ground-based optical and near-infrared observations of SN 2005hk and SN 2008A, typical members of the Type Iax class of supernovae

  12. AN OBSERVED CORRELATION BETWEEN THERMAL AND NON-THERMAL EMISSION IN

    Office of Scientific and Technical Information (OSTI)

    GAMMA-RAY BURSTS (Journal Article) | SciTech Connect AN OBSERVED CORRELATION BETWEEN THERMAL AND NON-THERMAL EMISSION IN GAMMA-RAY BURSTS Citation Details In-Document Search Title: AN OBSERVED CORRELATION BETWEEN THERMAL AND NON-THERMAL EMISSION IN GAMMA-RAY BURSTS Recent observations by the Fermi Gamma-ray Space Telescope have confirmed the existence of thermal and non-thermal components in the prompt photon spectra of some gamma-ray bursts (GRBs). Through an analysis of six bright Fermi

  13. Sweetspot: Near-infrared observations of 13 type Ia supernovae from a new

    Office of Scientific and Technical Information (OSTI)

    NOAO survey probing the nearby smooth Hubble flow (Journal Article) | SciTech Connect Sweetspot: Near-infrared observations of 13 type Ia supernovae from a new NOAO survey probing the nearby smooth Hubble flow Citation Details In-Document Search Title: Sweetspot: Near-infrared observations of 13 type Ia supernovae from a new NOAO survey probing the nearby smooth Hubble flow We present 13 Type Ia supernovae (SNe Ia) observed in the rest-frame near-infrared (NIR) from 0.02 < z < 0.09

  14. Phonon softening near the structural transition in BaFe2As2 observed...

    Office of Scientific and Technical Information (OSTI)

    Phonon softening near the structural transition in BaFe2As2 observed by inelastic x-ray scattering Citation Details In-Document Search Title: Phonon softening near the structural ...

  15. Observation of Rayleigh-Taylor-instability evolution in a plasma with magnetic and viscous effects

    SciTech Connect (OSTI)

    Adams, Colin S.; Moser, Auna L.; Hsu, Scott C.

    2015-11-06

    We present time-resolved observations of Rayleigh-Taylor-instability (RTI) evolution at the interface between an unmagnetized plasma jet colliding with a stagnated, magnetized plasma. The observed instability growth time (~10μs) is consistent with the estimated linear RTI growth rate calculated using experimentally inferred values of density (~1014cm–3) and deceleration (~109 m/s2). The observed mode wavelength (≳1 cm) nearly doubles within a linear growth time. Furthermore, theoretical estimates of magnetic and viscous stabilization and idealized magnetohydrodynamic simulations including a physical viscosity model both suggest that the observed instability evolution is subject to magnetic and/or viscous effects.

  16. CONFRONTING THREE-DIMENSIONAL TIME-DEPENDENT JET SIMULATIONS WITH HUBBLE SPACE TELESCOPE OBSERVATIONS

    SciTech Connect (OSTI)

    Staff, Jan E.; Niebergal, Brian P.; Ouyed, Rachid; Pudritz, Ralph E.; Cai, Kai

    2010-10-20

    We perform state-of-the-art, three-dimensional, time-dependent simulations of magnetized disk winds, carried out to simulation scales of 60 AU, in order to confront optical Hubble Space Telescope observations of protostellar jets. We 'observe' the optical forbidden line emission produced by shocks within our simulated jets and compare these with actual observations. Our simulations reproduce the rich structure of time-varying jets, including jet rotation far from the source, an inner (up to 400 km s{sup -1}) and outer (less than 100 km s{sup -1}) component of the jet, and jet widths of up to 20 AU in agreement with observed jets. These simulations when compared with the data are able to constrain disk wind models. In particular, models featuring a disk magnetic field with a modest radial spatial variation across the disk are favored.

  17. Pervasive faint Fe XIX emission from a solar active region observed...

    Office of Scientific and Technical Information (OSTI)

    from a solar active region observed with EUNIS-13: Evidence for nanoflare heating Citation Details In-Document Search Title: Pervasive faint Fe XIX emission from a solar active ...

  18. Observation of Temperature-Induced Crossover to an Orbital-Selective...

    Office of Scientific and Technical Information (OSTI)

    Temperature-Induced Crossover to an Orbital-Selective Mott Phase in AxFe2-ySe2 (AK, Rb) Superconductors Citation Details In-Document Search Title: Observation of Temperature-Induc...

  19. Information Content of a New Observable: The Case of the Nuclear...

    Office of Scientific and Technical Information (OSTI)

    The Case of the Nuclear Neutron Skin Citation Details In-Document Search Title: Information Content of a New Observable: The Case of the Nuclear Neutron Skin The radius ...

  20. Bringing simulation and observation together to better understand the intergalactic medium

    SciTech Connect (OSTI)

    Egan, Hilary; Smith, Britton D.; O'Shea, Brian W.; Shull, J. Michael

    2014-08-10

    The methods by which one characterizes the distribution of matter in cosmological simulations is intrinsically different from how one performs the same task observationally. In this paper, we make substantial steps toward comparing simulations and observations of the intergalactic medium (IGM) in a more sensible way. We present a pipeline that generates and fits synthetic QSO absorption spectra using sight lines cast through a cosmological simulation, and simultaneously identifies structure by directly analyzing the variations in H I and O VI number density. We compare synthetic absorption spectra with a less observationally motivated, but more straightforward density threshold-based method for finding absorbers. Our efforts focus on H I and O VI to better characterize the warm/hot IGM, a subset of the IGM that is challenging to conclusively identify observationally. We find that the two methods trace roughly the same quantities of H I and O VI above observable column density limits, but the synthetic spectra typically identify more substructure in absorbers. We use both methods to characterize H I and O VI absorber properties. We find that both integrated and differential column density distributions from both methods generally agree with observations. The distribution of Doppler parameters between the two methods are similar for Ly? and compare reasonably with observational results, but while the two methods agree with each other with O VI systems, they both are systematically different from observations. We find a strong correlation between O VI baryon fraction and O VI column density. We also discuss a possible bimodality in the temperature distribution of the gas traced by O VI.

  1. Working Group Reports Summary of Single-Column Model Intensive Observation

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

    Working Group Reports Summary of Single-Column Model Intensive Observation Period Workshop at Annual Atmospheric Radiation Measurement Science Team Meeting D. A. Randall Department of Atmospheric Science Colorado State University Fort Collins, Colorado R. T. Cederwall Lawrence Livermore National Laboratory Livermore, California * Study previous observation simulation system experiments (OSSEs) (i.e., Bill Frank, Pennsylvania State University [PSU]) and conduct OSSEs as necessary to evaluate

  2. Experimental observation of 3-D, impulsive reconnection events in a laboratory plasma

    SciTech Connect (OSTI)

    Dorfman, S.; Ji, H.; Yamada, M.; Yoo, J.; Lawrence, E.; Myers, C.; Tharp, T. D.

    2014-01-15

    Fast, impulsive reconnection is commonly observed in laboratory, space, and astrophysical plasmas. In this work, impulsive, local, 3-D reconnection is identified for the first time in a laboratory current sheet. The two-fluid, impulsive reconnection events observed on the Magnetic Reconnection Experiment (MRX) [Yamada et al., Phys Plasmas 4, 1936 (1997)] cannot be explained by 2-D models and are therefore fundamentally three-dimensional. Several signatures of flux ropes are identified with these events; 3-D high current density regions with O-point structure form during a slow buildup period that precedes a fast disruption of the reconnecting current layer. The observed drop in the reconnection current and spike in the reconnection rate during the disruption are due to ejection of these flux ropes from the layer. Underscoring the 3-D nature of the events, strong out-of-plane gradients in both the density and reconnecting magnetic field are found to play a key role in this process. Electromagnetic fluctuations in the lower hybrid frequency range are observed to peak at the disruption time; however, they are not the key physics responsible for the impulsive phenomena observed. Important features of the disruption dynamics cannot be explained by an anomalous resistivity model. An important discrepancy in the layer width and force balance between the collisionless regime of MRX and kinetic simulations is also revisited. The wider layers observed in MRX may be due to the formation of flux ropes with a wide range of sizes; consistent with this hypothesis, flux rope signatures are observed down to the smallest scales resolved by the diagnostics. Finally, a 3-D two-fluid model is proposed to explain how the observed out-of-plane variation may lead to a localized region of enhanced reconnection that spreads in the direction of the out-of-plane electron flow, ejecting flux ropes from the layer in a 3-D manner.

  3. On the observation of multiple volume reflection from different planes inside one bent crystal

    SciTech Connect (OSTI)

    Guidi, Vincenzo; Mazzolari, Andrea; Tikhomirov, Victor

    2010-06-15

    An interpretation of the first experiment on the observation of 400 GeV proton multiple volume reflection from different skew planes of one bent crystal (MVROC) is given. The possibilities of experimental observation of MVROC at lower particle energies are demonstrated. New features of the effect of particle capture into the channeling regime by bent skew planes are revealed as well as optimal choice of main crystal axis, crystal thickness, and beam orientation with respect to the crystal is discussed.

  4. Observed and modeled ecosystem isoprene fluxes from an oak-dominated

    Office of Scientific and Technical Information (OSTI)

    temperate forest and the influence of drought stress (Journal Article) | SciTech Connect Observed and modeled ecosystem isoprene fluxes from an oak-dominated temperate forest and the influence of drought stress Citation Details In-Document Search Title: Observed and modeled ecosystem isoprene fluxes from an oak-dominated temperate forest and the influence of drought stress Ecosystem fluxes of isoprene emission were measured during the majority of the 2011 growing season at the University of

  5. Intercomparison of model simulations of mixed-phase clouds observed during

    Office of Scientific and Technical Information (OSTI)

    the ARM Mixed-Phase Arctic Cloud Experiment. I: Single layer cloud (Journal Article) | SciTech Connect Journal Article: Intercomparison of model simulations of mixed-phase clouds observed during the ARM Mixed-Phase Arctic Cloud Experiment. I: Single layer cloud Citation Details In-Document Search Title: Intercomparison of model simulations of mixed-phase clouds observed during the ARM Mixed-Phase Arctic Cloud Experiment. I: Single layer cloud Results are presented from an intercomparison of

  6. Experimental observation of acoustic sub-harmonic diffraction by a grating

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect Experimental observation of acoustic sub-harmonic diffraction by a grating Citation Details In-Document Search Title: Experimental observation of acoustic sub-harmonic diffraction by a grating A diffraction grating is a spatial filter causing sound waves or optical waves to reflect in directions determined by the frequency of the waves and the period of the grating. The classical grating equation is the governing principle that has successfully described

  7. NuSTAR Observations of the Bullet Cluster: Constraints on Inverse Compton

    Office of Scientific and Technical Information (OSTI)

    Emission (Journal Article) | SciTech Connect SciTech Connect Search Results Journal Article: NuSTAR Observations of the Bullet Cluster: Constraints on Inverse Compton Emission Citation Details In-Document Search Title: NuSTAR Observations of the Bullet Cluster: Constraints on Inverse Compton Emission Authors: Wik, Daniel R. ; /NASA, Goddard /Johns Hopkins U. ; Hornstrup, A. ; /Denmark, Tech. U. ; Molendi, S. ; /IASF, Milan ; Madejski, G. ; /KIPAC, Menlo Park /SLAC ; Harrison, F. A. ;

  8. Amazon Column CO2 and CO Observations to Elucidate Tropical Ecosystem

    Office of Scientific and Technical Information (OSTI)

    Processes (Conference) | SciTech Connect Conference: Amazon Column CO2 and CO Observations to Elucidate Tropical Ecosystem Processes Citation Details In-Document Search Title: Amazon Column CO2 and CO Observations to Elucidate Tropical Ecosystem Processes Authors: Dubey, Manvendra Krishna [1] ; Parker, Harrison Alexander [1] ; Myers, Katherine Elizabeth [1] ; Wennberg, P [2] ; Wunch, D [2] ; Allen, N [3] ; Blavier, J-F [4] ; Keppel-Aleks, G [5] ; O'Dell, C [6] ; Miller, J [7] ; Michalak, A

  9. Observation of Shot Noise Suppression at Optical Wavelengths in a Relativistic Electron Beam

    SciTech Connect (OSTI)

    Ratner, Daniel; Stupakov, Gennady; /SLAC

    2012-06-19

    Control of collective properties of relativistic particles is increasingly important in modern accelerators. In particular, shot noise affects accelerator performance by driving instabilities or by competing with coherent processes. We present experimental observations of shot noise suppression in a relativistic beam at the Linac Coherent Light Source. By adjusting the dispersive strength of a chicane, we observe a decrease in the optical transition radiation emitted from a downstream foil. We show agreement between the experimental results, theoretical models, and 3D particle simulations.

  10. SPECKLE INTERFEROMETRY AT THE USNO FLAGSTAFF STATION: OBSERVATIONS OBTAINED IN 2008 AND NINE NEW ORBITS

    SciTech Connect (OSTI)

    Hartkopf, William I.; Mason, Brian D. E-mail: bdm@usno.navy.mil

    2011-08-15

    Results are presented for 299 speckle interferometric observations of double stars, obtained in 2008 at the USNO Flagstaff Station using the 1.55 m Kaj Strand Astrometric Reflector. Separations range from 0.''15 to 9.''88, with a median of 2.''22. This observing run concentrated on neglected systems, as well as systems in need of improved orbital elements; new orbital solutions have been determined for nine systems as a result.

  11. Clear Skies A Study of Longwave Radiation Codes for Climate Studies: Validation with Observations

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

    A Study of Longwave Radiation Codes for Climate Studies: Validation with Observations and Tests in General Circulation Models-an Update R. G. Ellingson and F. Baer Department of Meteorology University of Maryland College Park, MD 20742 Introduction to compare calculations from a set of models with operationally observed data. The differences we find will lead to the development of new models to be tested with new data. Similarly. our GCM studies will use existing GCMs to study the radiation

  12. Observing the Sparks of Life | U.S. DOE Office of Science (SC)

    Office of Science (SC) Website

    Observing the Sparks of Life Energy Frontier Research Centers (EFRCs) EFRCs Home Centers Research Science Highlights News & Events EFRC News EFRC Events DOE Announcements Publications History Contact BES Home 12.30.13 Observing the Sparks of Life Print Text Size: A A A Subscribe FeedbackShare Page EFRC researchers isolate a photosynthetic complex - arguably the most important bit of organic chemistry on the planet - in its complete functioning state. This work, featured in the Office of

  13. Observing System Simulation Experiments (OSSEs) for the Mid-Columbia Basin

    SciTech Connect (OSTI)

    Zack, J; Natenberg, E J; Knowe, G V; Waight, K; Manobianco, J; Hanley, D; Kamath, C

    2011-09-13

    The overall goal of this multi-phased research project known as WindSENSE is to develop an observation system deployment strategy that would improve wind power generation forecasts. The objective of the deployment strategy is to produce the maximum benefit for 1- to 6-hour ahead forecasts of wind speed at hub-height ({approx}80 m). In this phase of the project the focus is on the Mid-Columbia Basin region, which encompasses the Bonneville Power Administration (BPA) wind generation area (Figure 1) that includes the Klondike, Stateline, and Hopkins Ridge wind plants. There are two tasks in the current project effort designed to validate the Ensemble Sensitivity Analysis (ESA) observational system deployment approach in order to move closer to the overall goal: (1) Perform an Observing System Experiment (OSE) using a data denial approach. The results of this task are presented in a separate report. (2) Conduct a set of Observing System Simulation Experiments (OSSE) for the Mid-Colombia basin region. This report presents the results of the OSSE task. The specific objective is to test strategies for future deployment of observing systems in order to suggest the best and most efficient ways to improve wind forecasting at BPA wind farm locations. OSSEs have been used for many years in meteorology to evaluate the potential impact of proposed observing systems, determine tradeoffs in instrument design, and study the most effective data assimilation methodologies to incorporate the new observations into numerical weather prediction (NWP) models (Atlas 1997; Lord 1997). For this project, a series of OSSEs will allow consideration of the impact of new observing systems of various types and in various locations.

  14. Evaluation of PM-3 Chemistry Data and Possible Interpretations of 3H Observations, Revision 0

    SciTech Connect (OSTI)

    Andrews, Robert; Marutzky, Sam J.

    2015-02-01

    This report summarizes the analyses of the groundwater results from sampling of PM-3-1 (deep) and PM-3-2 (shallow), with a particular focus of evaluating the groundwater geochemistry data in comparison to the geochemistry observed in other wells in the Thirsty Canyon area as well as to evaluate the potential source of 3H observed in these piezometers from previous sampling activities, which employed depth-discrete bailers or a Bennett submersible piston pump.

  15. SPATIALLY DEPENDENT HEATING AND IONIZATION IN AN ICME OBSERVED BY BOTH ACE AND ULYSSES

    SciTech Connect (OSTI)

    Lepri, Susan T.; Laming, J. Martin; Rakowski, Cara E.; Von Steiger, Rudolf

    2012-12-01

    The 2005 January 21 interplanetary coronal mass ejection (ICME) observed by multiple spacecraft at L1 was also observed from January 21-February 4 at Ulysses (5.3 AU). Previous studies of this ICME have found evidence suggesting that the flanks of a magnetic cloud like structure associated with this ICME were observed at L1 while a more central cut through the associated magnetic cloud was observed at Ulysses. This event allows us to study spatial variation across the ICME and relate it to the eruption at the Sun. In order to examine the spatial dependence of the heating in this ICME, we present an analysis and comparison of the heavy ion composition observed during the passage of the ICME at L1 and at Ulysses. Using SWICS, we compare the heavy ion composition across the two different observation cuts through the ICME and compare it with predictions for heating during the eruption based on models of the time-dependent ionization balance throughout the event.

  16. Detection of ocean glint and ozone absorption using LCROSS Earth observations

    SciTech Connect (OSTI)

    Robinson, Tyler D.; Ennico, Kimberly; Meadows, Victoria S.; Sparks, William; Schwieterman, Edward W.; Bussey, D. Ben J.; Breiner, Jonathan

    2014-06-01

    The Lunar CRater Observation and Sensing Satellite (LCROSS) observed the distant Earth on three occasions in 2009. These data span a range of phase angles, including a rare crescent phase view. For each epoch, the satellite acquired near-infrared and mid-infrared full-disk images, and partial-disk spectra at 0.26-0.65 ?m (?/?? ? 500) and 1.17-2.48 ?m (?/?? ? 50). Spectra show strong absorption features due to water vapor and ozone, which is a biosignature gas. We perform a significant recalibration of the UV-visible spectra and provide the first comparison of high-resolution visible Earth spectra to the NASA Astrobiology Institute's Virtual Planetary Laboratory three-dimensional spectral Earth model. We find good agreement with the observations, reproducing the absolute brightness and dynamic range at all wavelengths for all observation epochs, thus validating the model to within the ?10% data calibration uncertainty. Data-model comparisons reveal a strong ocean glint signature in the crescent phase data set, which is well matched by our model predictions throughout the observed wavelength range. This provides the first observational test of a technique that could be used to determine exoplanet habitability from disk-integrated observations at visible and near-infrared wavelengths, where the glint signal is strongest. We examine the detection of the ozone 255 nm Hartley and 400-700 nm Chappuis bands. While the Hartley band is the strongest ozone feature in Earth's spectrum, false positives for its detection could exist. Finally, we discuss the implications of these findings for future exoplanet characterization missions.

  17. Observations of giant pulses from pulsar B0950+08 using LWA1

    SciTech Connect (OSTI)

    Tsai, Jr-Wei; Simonetti, John H.; Bear, Brandon; Akukwe, Bernadine; Quezada, Leandro; Kavic, Michael; Cutchin, Sean E.; Dowell, Jayce; Schinzel, Frank K.; Taylor, Gregory B.; Gough, Jonathan D.; Kanner, Jonah; Kassim, Namir E.; Shawhan, Peter; Yancey, Cregg C.

    2015-02-01

    We report the detection of giant pulse (GP) emission from PSR B0950+08 in 24 hours of observations made at 39.4 MHz, with a bandwidth of 16 MHz, using the first station of the Long Wavelength Array. We detected 119 GPs from PSR B0950+08 (at its dispersion measure (DM)), which we define as having a signal-to-noise ratio at least 10 times larger than for the mean pulse in our data set. These 119 pulses are 0.035% of the total number of pulse periods in the 24 hours of observations. The rate of GPs is about 5.0 per hour. The cumulative distribution of pulse strength S is a steep power law, N(>S)?S{sup ?4.7}, but much less steep than would be expected if we were observing the tail of a Gaussian distribution of normal pulses. We detected no other transient pulses in a DM range from 1 to 90 pc cm{sup ?3}, in the beam tracking PSR B0950+08. The GPs have a narrower temporal width than the mean pulse (17.8 ms, on average, versus 30.5 ms). The pulse widths are consistent with a previously observed weak dependence on observing frequency, which may be indicative of a deviation from a Kolmogorov spectrum of electron density irregularities along the line of sight. The rate and strength of these GPs is less than has been observed at ?100 MHz. Additionally, the mean (normal) pulse flux density we observed is less than at ?100 MHz. These results suggest this pulsar is weaker and produces less frequent GPs at 39 MHz than at 100 MHz.

  18. ANTI-PARALLEL EUV FLOWS OBSERVED ALONG ACTIVE REGION FILAMENT THREADS WITH HI-C

    SciTech Connect (OSTI)

    Alexander, Caroline E.; Walsh, Robert W.; Rgnier, Stphane; Cirtain, Jonathan; Winebarger, Amy R.; Golub, Leon; Korreck, Kelly; Weber, Mark; Kobayashi, Ken; Platt, Simon; Mitchell, Nick; DePontieu, Bart; Title, Alan; DeForest, Craig; Kuzin, Sergey

    2013-09-20

    Plasma flows within prominences/filaments have been observed for many years and hold valuable clues concerning the mass and energy balance within these structures. Previous observations of these flows primarily come from H? and cool extreme-ultraviolet (EUV) lines (e.g., 304 ) where estimates of the size of the prominence threads has been limited by the resolution of the available instrumentation. Evidence of 'counter-steaming' flows has previously been inferred from these cool plasma observations, but now, for the first time, these flows have been directly imaged along fundamental filament threads within the million degree corona (at 193 ). In this work, we present observations of an AR filament observed with the High-resolution Coronal Imager (Hi-C) that exhibits anti-parallel flows along adjacent filament threads. Complementary data from the Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA) and Helioseismic and Magnetic Imager are presented. The ultra-high spatial and temporal resolution of Hi-C allow the anti-parallel flow velocities to be measured (70-80 km s{sup 1}) and gives an indication of the resolvable thickness of the individual strands (0.''8 0.''1). The temperature of the plasma flows was estimated to be log T (K) = 5.45 0.10 using Emission Measure loci analysis. We find that SDO/AIA cannot clearly observe these anti-parallel flows or measure their velocity or thread width due to its larger pixel size. We suggest that anti-parallel/counter-streaming flows are likely commonplace within all filaments and are currently not observed in EUV due to current instrument spatial resolution.

  19. FULLY RESOLVED QUIET-SUN MAGNETIC FLUX TUBE OBSERVED WITH THE SUNRISE/IMAX INSTRUMENT

    SciTech Connect (OSTI)

    Lagg, A.; Solanki, S. K.; Riethmueller, T. L.; Schuessler, M.; Hirzberger, J.; Feller, A.; Borrero, J. M.; Barthol, P.; Gandorfer, A.; MartInez Pillet, V.; Bonet, J. A.; Del Toro Iniesta, J. C.; Domingo, V.; Knoelker, M.; Title, A. M.

    2010-11-10

    Until today, the small size of magnetic elements in quiet-Sun areas has required the application of indirect methods, such as the line-ratio technique or multi-component inversions, to infer their physical properties. A consistent match to the observed Stokes profiles could only be obtained by introducing a magnetic filling factor that specifies the fraction of the observed pixel filled with magnetic field. Here, we investigate the properties of a small magnetic patch in the quiet Sun observed with the IMaX magnetograph on board the balloon-borne telescope SUNRISE with unprecedented spatial resolution and low instrumental stray light. We apply an inversion technique based on the numerical solution of the radiative transfer equation to retrieve the temperature stratification and the field strength in the magnetic patch. The observations can be well reproduced with a one-component, fully magnetized atmosphere with a field strength exceeding 1 kG and a significantly enhanced temperature in the mid to upper photosphere with respect to its surroundings, consistent with semi-empirical flux tube models for plage regions. We therefore conclude that, within the framework of a simple atmospheric model, the IMaX measurements resolve the observed quiet-Sun flux tube.

  20. MULTI-WAVELENGTH OBSERVATIONS OF COMET C/2011 L4 (PAN-STARRS)

    SciTech Connect (OSTI)

    Yang, Bin; Keane, Jacqueline; Meech, Karen; Owen, Tobias; Wainscoat, Richard

    2014-04-01

    The dynamically new comet C/2011 L4 (Pan-STARRS) is one of the brightest comets observed since the great comet C/1995 O1 (Hale-Bopp). Here, we present our multi-wavelength observations of C/2011 L4 during its in-bound passage to the inner solar system. A strong absorption band of water ice at 2.0 ?m was detected in the near-infrared spectra, obtained with the 8m Gemini-North and 3m Infrared Telescope Facility Telescopes. The companion 1.5 ?m band of water ice, however, was not observed. Spectral modeling shows that the absence of the 1.5 ?m feature can be explained by the presence of sub-micron-sized fine ice grains. No gas lines (i.e., CN, HCN, or CO) were observed pre-perihelion in either the optical or the submillimeter. We derived 3? upper limits for the CN and CO production rates. The comet exhibited a very strong continuum in the optical and its slope seemed to become redder as the comet approached the Sun. Our observations suggest that C/2011 L4 is an unusually dust-rich comet with a dust-to-gas mass ratio >4.

  1. ALMA OBSERVATIONS OF THE OUTFLOW FROM SOURCE I IN THE ORION-KL REGION

    SciTech Connect (OSTI)

    Zapata, Luis A.; Rodriguez, Luis F.; Loinard, Laurent; Schmid-Burgk, Johannes; Menten, Karl M.; Curiel, Salvador

    2012-07-20

    In this Letter, we present sensitive millimeter SiO (J = 5-4; {nu} = 0) line observations of the outflow arising from the enigmatic object Orion Source I made with the Atacama Large Millimeter/Submillimeter Array (ALMA). The observations reveal that at scales of a few thousand AU, the outflow has a marked 'butterfly' morphology along a northeast-southwest axis. However, contrary to what is found in the SiO and H{sub 2}O maser observations at scales of tens of AU, the blueshifted radial velocities of the moving gas are found to the northwest, while the redshifted velocities are in the southeast. The ALMA observations are complemented with SiO (J = 8-7; {nu} = 0) maps (with a similar spatial resolution) obtained with the Submillimeter Array. These observations also show a similar morphology and velocity structure in this outflow. We discuss some possibilities to explain these differences at small and large scales across the flow.

  2. GROUND-BASED TRANSIT OBSERVATIONS OF THE SUPER-EARTH 55 Cnc e

    SciTech Connect (OSTI)

    De Mooij, E. J. W.; Lpez-Morales, M.; Karjalainen, R.; Hrudkova, M.; Jayawardhana, Ray

    2014-12-20

    We report the first ground-based detections of the shallow transit of the super-Earth exoplanet 55Cnce using a 2 m class telescope. Using differential spectrophotometry, we observed one transit in 2013 and another in 2014, with average spectral resolutions of ?700 and ?250, spanning the Johnson BVR photometric bands. We find a white light planet-to-star radius ratio of 0.0190{sub ?0.0027}{sup +0.0023} from the 2013 observations and 0.0200{sub ?0.0018}{sup +0.0017} from the 2014 observations. The two data sets combined result in a radius ratio of 0.0198{sub ?0.0014}{sup +0.0013}. These values are all in agreement with previous space-based results. Scintillation noise in the data prevents us from placing strong constraints on the presence of an extended hydrogen-rich atmosphere. Nevertheless, our detections of 55Cnce in transit demonstrate that moderate-sized telescopes on the ground will be capable of routine follow-up observations of super-Earth candidates discovered by the Transiting Exoplanet Survey Satellite around bright stars. We expect it also will be possible to place constraints on the atmospheric characteristics of those planets by devising observational strategies to minimize scintillation noise.

  3. OBSERVATION OF HEATING BY FLARE-ACCELERATED ELECTRONS IN A SOLAR CORONAL MASS EJECTION

    SciTech Connect (OSTI)

    Glesener, Lindsay; Bain, Hazel M.; Krucker, Sm; Lin, Robert P.

    2013-12-20

    We report a Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) observation of flare-accelerated electrons in the core of a coronal mass ejection (CME) and examine their role in heating the CME. Previous CME observations have revealed remarkably high thermal energies that can far surpass the CME's kinetic energy. A joint observation by RHESSI and the Atmospheric Imaging Assembly of a partly occulted flare on 2010 November 3 allows us to test the hypothesis that this excess energy is collisionally deposited by flare-accelerated electrons. Extreme ultraviolet (EUV) images show an ejection forming the CME core and sheath, with isothermal multifilter analysis revealing temperatures of ?11MK in the core. RHESSI images reveal a large (?100 50 arcsec{sup 2}) hard X-ray (HXR) source matching the location, shape, and evolution of the EUV plasma, indicating that the emerging CME is filled with flare-accelerated electrons. The time derivative of the EUV emission matches the HXR light curve (similar to the Neupert effect observed in soft and HXR time profiles), directly linking the CME temperature increase with the nonthermal electron energy loss, while HXR spectroscopy demonstrates that the nonthermal electrons contain enough energy to heat the CME. This is the most direct observation to date of flare-accelerated electrons heating a CME, emphasizing the close relationship of the two in solar eruptive events.

  4. Mechanisms and observations of coronal dimming for the 201 August 7 event

    SciTech Connect (OSTI)

    Mason, James Paul; Woods, T. N.; Caspi, A.; Thompson, B. J.; Hock, R. A.

    2014-07-01

    Coronal dimming of extreme ultraviolet (EUV) emission has the potential to be a useful forecaster of coronal mass ejections (CMEs). As emitting material leaves the corona, a temporary void is left behind which can be observed in spectral images and irradiance measurements. The velocity and mass of the CMEs should impact the character of those observations. However, other physical processes can confuse the observations. We describe these processes and the expected observational signature, with special emphasis placed on the differences. We then apply this understanding to a coronal dimming event with an associated CME that occurred on 2010 August 7. Data from the Solar Dynamics Observatory's Atmospheric Imaging Assembly and EUV Variability Experiment (EVE) are used for observations of the dimming, while the Solar and Heliospheric Observatory's Large Angle and Spectrometric Coronagraph and the Solar Terrestrial Relations Observatory's COR1 and COR2 are used to obtain velocity and mass estimates for the associated CME. We develop a technique for mitigating temperature effects in coronal dimming from full-disk irradiance measurements taken by EVE. We find that for this event, nearly 100% of the dimming is due to mass loss in the corona.

  5. Direct constraints on minimal supersymmetry from Fermi-LAT observations of the dwarf galaxy Segue 1

    SciTech Connect (OSTI)

    Scott, Pat; Conrad, Jan; Edsj, Joakim; Bergstrm, Lars; Akrami, Yashar; Farnier, Christian E-mail: conrad@fysik.su.se E-mail: lbe@fysik.su.se E-mail: yashar@fysik.su.se

    2010-01-01

    The dwarf galaxy Segue 1 is one of the most promising targets for the indirect detection of dark matter. Here we examine what constraints 9 months of Fermi-LAT gamma-ray observations of Segue 1 place upon the Constrained Minimal Supersymmetric Standard Model (CMSSM), with the lightest neutralino as the dark matter particle. We use nested sampling to explore the CMSSM parameter space, simultaneously fitting other relevant constraints from accelerator bounds, the relic density, electroweak precision observables, the anomalous magnetic moment of the muon and B-physics. We include spectral and spatial fits to the Fermi observations, a full treatment of the instrumental response and its related uncertainty, and detailed background models. We also perform an extrapolation to 5 years of observations, assuming no signal is observed from Segue 1 in that time. Results marginally disfavour models with low neutralino masses and high annihilation cross-sections. Virtually all of these models are however already disfavoured by existing experimental or relic density constraints.

  6. OBSERVATIONAL IMPLICATIONS OF GAMMA-RAY BURST AFTERGLOW JET SIMULATIONS AND NUMERICAL LIGHT CURVE CALCULATIONS

    SciTech Connect (OSTI)

    Van Eerten, Hendrik J.; MacFadyen, Andrew I.

    2012-06-01

    We discuss jet dynamics for narrow and wide gamma-ray burst (GRB) afterglow jets and the observational implications of numerical simulations of relativistic jets in two dimensions. We confirm earlier numerical results that sideways expansion of relativistic jets during the bulk of the afterglow emission phase is logarithmic in time and find that this also applies to narrow jets with half opening angle of 0.05 rad. As a result, afterglow jets remain highly nonspherical until after they have become nonrelativistic. Although sideways expansion steepens the afterglow light curve after the jet break, the jet edges becoming visible dominates the jet break, which means that the jet break is sensitive to the observer angle even for narrow jets. Failure to take the observer angle into account can lead to an overestimation of the jet energy by up to a factor of four. This weakens the challenge posed to the magneter energy limit by extreme events such as GRB090926A. Late-time radio calorimetry based on a spherical nonrelativistic outflow model remains relevant when the observer is approximately on-axis and where differences of a few in flux level between the model and the simulation are acceptable. However, this does not imply sphericity of the outflow and therefore does not translate to high observer angles relevant to orphan afterglows. For more accurate calorimetry and in order to model significant late-time features such as the rise of the counterjet, detailed jet simulations remain indispensable.

  7. U.S. DEPARTJl.1ENT OF ENERGY EERE PROJECT MANAGEMENT CENTER

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

    1 of2 G) .. j' .. STATE: NY PROJECT TITLE; Improving atmospheric models for offshore wind resource mapping and prediction using UDAR , aircraft, and in-ocean observations...

  8. Cosmological observables in multi-field inflation with a non-flat field space

    SciTech Connect (OSTI)

    Gao, Xin; Li, Tianjun; Shukla, Pramod E-mail: tli@itp.ac.cn

    2014-10-01

    Using δN formalism, in the context of a generic multi-field inflation driven on a non-flat field space background, we revisit the analytic expressions of the various cosmological observables such as scalar/tensor power spectra, scalar/tensor spectral tilts, non-Gaussianity parameters, tensor-to-scalar ratio, and the various runnings of these observables. In our backward formalism approach, the subsequent expressions of observables automatically include the terms beyond the leading order slow-roll expansion correcting many of the expression at subleading order. To connect our analysis properly with the earlier results, we rederive the (well) known (single field) expressions in the limiting cases of our generic formulae. Further, in the light of PLANCK results, we examine for the compatibility of the consistency relations within the slow-roll regime of a two-field roulette poly-instanton inflation realized in the context of large volume scenarios.

  9. Observation of a Griffiths-like Phase in the Magnetocaloric Compound Tb{sub

    Office of Scientific and Technical Information (OSTI)

    5}Si{sub 2}Ge{sub 2} (Journal Article) | SciTech Connect Observation of a Griffiths-like Phase in the Magnetocaloric Compound Tb{sub 5}Si{sub 2}Ge{sub 2} Citation Details In-Document Search Title: Observation of a Griffiths-like Phase in the Magnetocaloric Compound Tb{sub 5}Si{sub 2}Ge{sub 2} The onset of a Griffiths-like phase has been observed in Tb{sub 5}Si{sub 2}Ge{sub 2} (T{sub C}=110 K) by means of magnetic susceptibility and small-angle neutron scattering experiments. We show the

  10. Bright microwave pulses from PSR B0531+21 observed with a prototype transient survey receiver

    SciTech Connect (OSTI)

    O'Dea, J. Andrew; Cheng, Tsan-Huei; Buu, Chau M.; Asmar, Sami W.; Armstrong, J. W.; Jenet, F. A.; Beroiz, Martin

    2014-05-01

    Recent discoveries of transient radio events have renewed interest in time-variable astrophysical phenomena. Many radio transient events are rare, requiring long observing times for reliable statistical study. The National Aeronautics and Space Administration/Jet Propulsion Laboratory's Deep Space Network (DSN) tracks spacecraft nearly continuously with 13 large-aperture, low system temperature radio antennas. During normal spacecraft operations, the DSN processes only a small fraction of the pre-detection bandwidth available from these antennas; any information in the remaining bandwidth, e.g., from an astronomical source in the same antenna beam as the spacecraft, is currently ignored. As a firmware modification to the standard DSN tracking receiver, we built a prototype receiver that could be used for astronomical transient surveys. Here, we demonstrate the receiver's utility through observations of bright pulses from the Crab pulsar and describe attributes of potential transient survey observations piggybacking on operational DSN tracks.

  11. A DOUBLE-PEAKED OUTBURST OF A 0535+26 OBSERVED WITH INTEGRAL, RXTE, AND SUZAKU

    SciTech Connect (OSTI)

    Caballero, I.; Barragan, L.; Wilms, J.; Kreykenbohm, I.; Ferrigno, C.; Klochkov, D.; Suchy, S.; Santangelo, A.; Staubert, R.; Zurita Heras, J. A.; Kretschmar, P.; Fuerst, F.; Rothschild, R.; Finger, M. H.; Camero-Arranz, A.; Makishima, K.; Enoto, T.; Iwakiri, W.; and others

    2013-02-20

    The Be/X-ray binary A 0535+26 showed a normal (type I) outburst in 2009 August. It is the fourth in a series of normal outbursts associated with the periastron, but is unusual because it presented a double-peaked light curve. The two peaks reached a flux of {approx}450 mCrab in the 15-50 keV range. We present results of the timing and spectral analysis of INTEGRAL, RXTE, and Suzaku observations of the outburst. The energy-dependent pulse profiles and their evolution during the outburst are studied. No significant differences with respect to other normal outbursts are observed. The centroid energy of the fundamental cyclotron line shows no significant variation during the outburst. A spectral hardening with increasing luminosity is observed. We conclude that the source is accreting in the sub-critical regime. We discuss possible explanations for the double-peaked outburst.

  12. PHOTOMETRY OF VARIABLE STARS FROM DOME A, ANTARCTICA: RESULTS FROM THE 2010 OBSERVING SEASON

    SciTech Connect (OSTI)

    Wang, Lingzhi; Zhu, Zonghong; Macri, Lucas M.; Wang, Lifan; Ashley, Michael C. B.; Lawrence, Jon S.; Luong-Van, Daniel; Storey, John W. V.; Cui, Xiangqun; Feng, Long-Long; Gong, Xuefei; Liu, Qiang; Shang, Zhaohui; Yang, Huigen; Yang, Ji; Yuan, Xiangyan; Zhou, Xu; Zhu, Zhenxi; Pennypacker, Carl R.; York, Donald G.

    2013-12-01

    We present results from a season of observations with the Chinese Small Telescope ARray, obtained over 183 days of the 2010 Antarctic winter. We carried out high-cadence time-series aperture photometry of 9125 stars with i ?< 15.3 mag located in a 23 deg{sup 2} region centered on the south celestial pole. We identified 188 variable stars, including 67 new objects relative to our 2008 observations, thanks to broader synoptic coverage, a deeper magnitude limit, and a larger field of view. We used the photometric data set to derive site statistics from Dome A. Based on two years of observations, we find that extinction due to clouds at this site is less than 0.1 and 0.4 mag during 45% and 75% of the dark time, respectively.

  13. Cloud radar Doppler spectra in drizzling stratiform clouds: 2. Observations and microphysical modeling of drizzle evolution

    SciTech Connect (OSTI)

    Kollias, P.; Luke, E.; Szyrmer, W.; Rmillard, J.

    2011-07-02

    In part I, the influence of cloud microphysics and dynamics on the shape of cloud radar Doppler spectra in warm stratiform clouds was discussed. The traditional analysis of radar Doppler moments was extended to include skewness and kurtosis as additional descriptors of the Doppler spectrum. Here, a short climatology of observed Doppler spectra moments as a function of the radar reflectivity at continental and maritime ARM sites is presented. The evolution of the Doppler spectra moments is consistent with the onset and growth of drizzle particles and can be used to assist modeling studies of drizzle onset and growth. Time-height radar observations are used to exhibit the coherency of the Doppler spectra shape parameters and demonstrate their potential to improve the interpretation and use of radar observations. In addition, a simplified microphysical approach to modeling the vertical evolution of the drizzle particle size distribution in warm stratiform clouds is described and used to analyze the observations. The formation rate of embryonic drizzle droplets due to the autoconversion process is not calculated explicitly; however, accretion and evaporation processes are explicitly modeled. The microphysical model is used as input to a radar Doppler spectrum forward model, and synthetic radar Doppler spectra moments are generated. Three areas of interest are studied in detail: early drizzle growth near the cloud top, growth by accretion of the well-developed drizzle, and drizzle depletion below the cloud base due to evaporation. The modeling results are in good agreement with the continental and maritime observations. This demonstrates that steady state one-dimensional explicit microphysical models coupled with a forward model and comprehensive radar Doppler spectra observations offer a powerful method to explore the vertical evolution of the drizzle particle size distribution.

  14. Observation of the Kondo effect in a spin-3/2 hole quantum dot

    SciTech Connect (OSTI)

    Klochan, O.; Micolich, A. P.; Hamilton, A. R.; Trunov, K.; Reuter, D.; Wieck, A. D.

    2013-12-04

    We report the observation of the Kondo effect in a spin-3/2 hole quantum dot formed near pinch-off in a GaAs quantum wire. We clearly observe two distinctive hallmarks of quantum dot Kondo physics. First, the zero-bias peak in the differential conductance splits an in-plane magnetic field and the splitting is independent of gate voltage. Second, the splitting rate is twice as large as that for the lowest one-dimensional subband. We show that the Zeeman splitting of the zero-bias peak is highly anisotropic and attribute this to the strong spin-orbit interaction for holes in GaAs.

  15. CANDELS: THE CONTRIBUTION OF THE OBSERVED GALAXY POPULATION TO COSMIC REIONIZATION

    SciTech Connect (OSTI)

    Finkelstein, Steven L.; Pawlik, Andreas H.; Papovich, Casey; Ryan, Russell E.; Ferguson, Henry C.; Koekemoer, Anton M.; Grogin, Norman A.; Dickinson, Mark; Finlator, Kristian; Giavalisco, Mauro; Cooray, Asantha; Dunlop, James S.; Faber, Sandy M.; Kocevski, Dale D.

    2012-10-20

    We present measurements of the specific ultraviolet luminosity density from a sample of 483 galaxies at 6 {approx}< z {approx}< 8. These galaxies were selected from new deep near-infrared Hubble Space Telescope imaging from the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey, Hubble UltraDeep Field 2009, and Wide Field Camera 3 Early Release Science programs. We investigate the contribution to reionization from galaxies that we observe directly, thus sidestepping the uncertainties inherent in complementary studies that have invoked assumptions regarding the intrinsic shape or the faint-end cutoff of the galaxy ultraviolet (UV) luminosity function. Due to our larger survey volume, wider wavelength coverage, and updated assumptions about the clumping of gas in the intergalactic medium (IGM), we find that the observable population of galaxies can sustain a fully reionized IGM at z = 6, if the average ionizing photon escape fraction (f {sub esc}) is {approx}30%. Our result contrasts with a number of previous studies that have measured UV luminosity densities at these redshifts that vary by a factor of five, with many concluding that galaxies could not complete reionization by z = 6 unless a large population of galaxies fainter than the detection limit were invoked, or extremely high values of f {sub esc} were present. The specific UV luminosity density from our observed galaxy samples at z = 7 and 8 is not sufficient to maintain a fully reionized IGM unless f {sub esc} > 50%. We examine the contribution from galaxies in different luminosity ranges and find that the sub-L* galaxies we detect are stronger contributors to the ionizing photon budget than the L > L* population, unless f {sub esc} is luminosity dependent. Combining our observations with constraints on the emission rate of ionizing photons from Ly{alpha} forest observations at z = 6, we find that we can constrain f {sub esc} < 34% (2{sigma}) if the observed galaxies are the only contributors to reionization, or <13% (2{sigma}) if the luminosity function extends to a limiting magnitude of M {sub UV} = -13. These escape fractions are sufficient to sustain an ionized IGM by z = 6. Current constraints on the high-redshift galaxy population imply that the volume ionized fraction of the IGM, while consistent with unity at z {<=} 6, appears to drop at redshifts not much higher than 7, consistent with a number of complementary reionization probes. If faint galaxies dominated the ionizing photon budget at z = 6-7, future extremely deep observations with the James Webb Space Telescope will probe deep enough to directly observe them, providing an indirect constraint on the global ionizing photon escape fraction.

  16. Direct observation of charge mediated lattice distortions in complex oxide solid solutions

    SciTech Connect (OSTI)

    Sang, Xiahan; Grimley, Everett D.; Niu, Changning; Irving, Douglas L.; LeBeau, James M.

    2015-02-09

    Using aberration corrected scanning transmission electron microscopy combined with advanced imaging methods, we directly observe atom column specific, picometer-scale displacements induced by local chemistry in a complex oxide solid solution. Displacements predicted from density functional theory were found to correlate with the observed experimental trends. Further analysis of bonding and charge distribution was used to clarify the mechanisms responsible for the detected structural behavior. By extending the experimental electron microscopy measurements to previously inaccessible length scales, we identified correlated atomic displacements linked to bond differences within the complex oxide structure.

  17. ARM - Field Campaign - Observations and Modeling of the Green Ocean Amazon:

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

    Oxidation Flow Reactor Reactor ARM Data Discovery Browse Data Related Campaigns Observations and Modeling of the Green Ocean Amazon (GOAMAZON) 2014.01.01, Martin, AMF Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Campaign : Observations and Modeling of the Green Ocean Amazon: Oxidation Flow Reactor 2014.01.20 - 2014.03.31 Lead Scientist : Jose-Luis Jimenez For data sets, see below. Abstract An Oxidation Flow Reactor (OFR) was used to

  18. Observation of Parametric X-Rays Produced by 400-GeV/C Protons in Bent

    Office of Scientific and Technical Information (OSTI)

    Crystals (Journal Article) | SciTech Connect Parametric X-Rays Produced by 400-GeV/C Protons in Bent Crystals Citation Details In-Document Search Title: Observation of Parametric X-Rays Produced by 400-GeV/C Protons in Bent Crystals Spectral maxima of parametric X-ray radiation (PXR) produced by 400 GeV/c protons in bent silicon crystals aligned with the beam have been observed in an experiment at the H8 external beam of the CERN SPS. The total yield of PXR photons was about 10{sup -6} per

  19. Observation of parametric X-rays produced by 400 GeV/c protons in bent

    Office of Scientific and Technical Information (OSTI)

    crystals (Journal Article) | SciTech Connect parametric X-rays produced by 400 GeV/c protons in bent crystals Citation Details In-Document Search Title: Observation of parametric X-rays produced by 400 GeV/c protons in bent crystals Spectral maxima of parametric X-ray radiation (PXR) produced by 400 GeV/c protons in bent silicon crystals aligned with the beam have been observed in an experiment at the H8 external beam of the CERN SPS. The total yield of PXR photons was about 10{sup -6} per

  20. Observation of the Integer Quantum Hall Effect in Record High-Mobility

    Office of Scientific and Technical Information (OSTI)

    Uniform Wafer-Scale Epitaxial Graphene Films Grown on the Si-Face of 6H-SiC(0001). (Journal Article) | SciTech Connect Observation of the Integer Quantum Hall Effect in Record High-Mobility Uniform Wafer-Scale Epitaxial Graphene Films Grown on the Si-Face of 6H-SiC(0001). Citation Details In-Document Search Title: Observation of the Integer Quantum Hall Effect in Record High-Mobility Uniform Wafer-Scale Epitaxial Graphene Films Grown on the Si-Face of 6H-SiC(0001). Abstract not provided.

  1. Observing Signatures of Cosmic Rays Using High-Energy Gamma-Ray Telescopes

    Office of Scientific and Technical Information (OSTI)

    (Conference) | SciTech Connect Conference: Observing Signatures of Cosmic Rays Using High-Energy Gamma-Ray Telescopes Citation Details In-Document Search Title: Observing Signatures of Cosmic Rays Using High-Energy Gamma-Ray Telescopes Authors: Reimer, Olaf ; /Innsbruck U. /KIPAC, Menlo Park Publication Date: 2013-06-20 OSTI Identifier: 1084282 Report Number(s): SLAC-PUB-15629 DOE Contract Number: AC02-76SF00515 Resource Type: Conference Resource Relation: Journal Name: PoS

  2. POSSIBLE ALTERATION OF ROCKS OBSERVED BY CHEMCAM ALONG THE TRAVERSE TO

    Office of Scientific and Technical Information (OSTI)

    GLENELG IN GALE CRATER ON MARS. (Technical Report) | SciTech Connect Technical Report: POSSIBLE ALTERATION OF ROCKS OBSERVED BY CHEMCAM ALONG THE TRAVERSE TO GLENELG IN GALE CRATER ON MARS. Citation Details In-Document Search Title: POSSIBLE ALTERATION OF ROCKS OBSERVED BY CHEMCAM ALONG THE TRAVERSE TO GLENELG IN GALE CRATER ON MARS. Authors: Berger, B. [1] ; Blaney, D. [2] ; Bridges, J. [3] ; Cousin, A. [1] ; Forni, O. [1] ; Gasnault, O. [1] ; Lasue, J. [1] ; Mangold, N. [4] ; Maurice, S.

  3. Phonon softening near the structural transition in BaFe2As2 observed by

    Office of Scientific and Technical Information (OSTI)

    inelastic x-ray scattering (Journal Article) | SciTech Connect Phonon softening near the structural transition in BaFe2As2 observed by inelastic x-ray scattering Citation Details In-Document Search Title: Phonon softening near the structural transition in BaFe2As2 observed by inelastic x-ray scattering Authors: Niedziela, Jennifer L. ; Parshall, D. ; Lokshin, K. A. ; Sefat, A. S. ; Alatas, A. ; Egami, T. Publication Date: 2011-12-15 OSTI Identifier: 1098411 Type: Publisher's Accepted

  4. Gamma-Ray Observations of a Giant Flare From the Magnetar Sgr 1806-20

    Office of Scientific and Technical Information (OSTI)

    (Technical Report) | SciTech Connect Gamma-Ray Observations of a Giant Flare From the Magnetar Sgr 1806-20 Citation Details In-Document Search Title: Gamma-Ray Observations of a Giant Flare From the Magnetar Sgr 1806-20 Magnetars comprise two classes of rotating neutron stars (Soft Gamma Repeaters (SGRs) and Anomalous X-ray Pulsars), whose X-ray emission is powered by an ultrastrong magnetic field, B {approx} 10{sup 15} G. Occasionally SGRs enter into active episodes producing many short

  5. Intercomparison of model simulations of mixed-phase clouds observed during

    Office of Scientific and Technical Information (OSTI)

    the ARM Mixed-Phase Arctic Cloud Experiment. Part I: Single layer cloud (Journal Article) | SciTech Connect Part I: Single layer cloud Citation Details In-Document Search Title: Intercomparison of model simulations of mixed-phase clouds observed during the ARM Mixed-Phase Arctic Cloud Experiment. Part I: Single layer cloud Results are presented from an intercomparison of single-column and cloud-resolving model simulations of a cold-air outbreak mixed-phase stratocumulus cloud observed during

  6. Method for determining the octane rating of gasoline samples by observing corresponding acoustic resonances therein

    DOE Patents [OSTI]

    Sinha, Dipen N. (Los Alamos, NM); Anthony, Brian W. (Clearfield, PA)

    1997-01-01

    A method for determining the octane rating of gasoline samples by observing corresponding acoustic resonances therein. A direct correlation between the octane rating of gasoline and the frequency of corresponding acoustic resonances therein has been experimentally observed. Therefore, the octane rating of a gasoline sample can be directly determined through speed of sound measurements instead of by the cumbersome process of quantifying the knocking quality of the gasoline. Various receptacle geometries and construction materials may be employed. Moreover, it is anticipated that the measurements can be performed on flowing samples in pipes, thereby rendering the present method useful in refineries and distilleries.

  7. Observations on Characterization of Defects in Coiled Tubing From Magnetic-Flux-Leakage Data

    SciTech Connect (OSTI)

    Timothy R. McJunkin; Karen S. Miller; Charles R. Tolle

    2006-04-01

    This paper presents observations on the sizing of automatically detected artificial flaws in coiled tubing samples using magnetic-flux-leakage data. Sixty-six artificial flaws of various shapes and types, ranging from 0.30 mm deep pits to slots with length of 9.5 mm, in 44.45 mm outer diameter pipe were analyzed. The detection algorithm and the information automatically extracted from the data are described. Observations on the capabilities and limitations for determining the size and shape of the flaws are discussed.

  8. Understanding Cognitive and Collaborative Work: Observations in an Electric Transmission Operations Control Center

    SciTech Connect (OSTI)

    Obradovich, Jodi H.

    2011-09-30

    This paper describes research that is part of an ongoing project to design tools to assist in the integration of renewable energy into the electric grid. These tools will support control room dispatchers in real-time system operations of the electric power transmission system which serves much of the Western United States. Field observations comprise the first phase of this research in which 15 operators have been observed over various shifts and times of day for approximately 90 hours. Findings describing some of the cognitive and environmental challenges of managing the dynamically changing electric grid are presented.

  9. Optical Observations of Gamma-Ray Bursts: Connections to GeV/TeV Jets

    Office of Scientific and Technical Information (OSTI)

    (Conference) | SciTech Connect Conference: Optical Observations of Gamma-Ray Bursts: Connections to GeV/TeV Jets Citation Details In-Document Search Title: Optical Observations of Gamma-Ray Bursts: Connections to GeV/TeV Jets Authors: Vestrand, W. Thomas [1] + Show Author Affiliations Los Alamos National Laboratory Publication Date: 2013-08-21 OSTI Identifier: 1091318 Report Number(s): LA-UR-13-26624 DOE Contract Number: AC52-06NA25396 Resource Type: Conference Resource Relation: Conference:

  10. POSSIBLE ALTERATION OF ROCKS OBSERVED BY CHEMCAM ALONG THE TRAVERSE TO

    Office of Scientific and Technical Information (OSTI)

    GLENELG IN GALE CRATER ON MARS. (Technical Report) | SciTech Connect POSSIBLE ALTERATION OF ROCKS OBSERVED BY CHEMCAM ALONG THE TRAVERSE TO GLENELG IN GALE CRATER ON MARS. Citation Details In-Document Search Title: POSSIBLE ALTERATION OF ROCKS OBSERVED BY CHEMCAM ALONG THE TRAVERSE TO GLENELG IN GALE CRATER ON MARS. Authors: Berger, B. [1] ; Blaney, D. [2] ; Bridges, J. [3] ; Cousin, A. [1] ; Forni, O. [1] ; Gasnault, O. [1] ; Lasue, J. [1] ; Mangold, N. [4] ; Maurice, S. [1] ; Meslin, P. Y.

  11. Observation of Ultra-high-energy Cosmic Rays with the ANITA Balloon-borne

    Office of Scientific and Technical Information (OSTI)

    Radio Interferometer (Journal Article) | SciTech Connect Observation of Ultra-high-energy Cosmic Rays with the ANITA Balloon-borne Radio Interferometer Citation Details In-Document Search Title: Observation of Ultra-high-energy Cosmic Rays with the ANITA Balloon-borne Radio Interferometer Authors: Hoover, S. ; /UCLA ; Nam, J. ; /Ewha Women's U., Seoul ; Gorham, P.W. ; /Hawaii U. ; Grashorn, E. ; /Ohio State U. ; Allison, P. ; /Hawaii U. ; Barwick, S.W. ; /UC, Irvine ; Beatty, J.J. ; /Ohio

  12. POSSIBLE ALTERATION OF ROCKS OBSERVED BY CHEMCAM ALONG THE TRAVERSE TO

    Office of Scientific and Technical Information (OSTI)

    GLENELG IN GALE CRATER ON MARS. (Technical Report) | SciTech Connect Technical Report: POSSIBLE ALTERATION OF ROCKS OBSERVED BY CHEMCAM ALONG THE TRAVERSE TO GLENELG IN GALE CRATER ON MARS. Citation Details In-Document Search Title: POSSIBLE ALTERATION OF ROCKS OBSERVED BY CHEMCAM ALONG THE TRAVERSE TO GLENELG IN GALE CRATER ON MARS. × You are accessing a document from the Department of Energy's (DOE) SciTech Connect. This site is a product of DOE's Office of Scientific and Technical

  13. Direct Observation of the Transition from Indirect to Direct Bandgap in

    Office of Scientific and Technical Information (OSTI)

    Atomically Thin Epitaxial MoSe2 (Journal Article) | SciTech Connect Direct Observation of the Transition from Indirect to Direct Bandgap in Atomically Thin Epitaxial MoSe2 Citation Details In-Document Search Title: Direct Observation of the Transition from Indirect to Direct Bandgap in Atomically Thin Epitaxial MoSe2 Authors: Zhang, Yi ; Chang, Tay-Rong ; Zhou, Bo ; Cui, Yong-Tao ; Yan, Hao ; Liu, Zhongkai ; Schmitt, Felix ; Lee, James ; Moore, Rob ; Chen, Yulin ; Lin, Hsin ; Jeng, Horng-Tay

  14. Direct Observation of the Transition from Indirect to Direct Bandgap in

    Office of Scientific and Technical Information (OSTI)

    Atomically Thin Epitaxial MoSe2 (Journal Article) | SciTech Connect Direct Observation of the Transition from Indirect to Direct Bandgap in Atomically Thin Epitaxial MoSe2 Citation Details In-Document Search Title: Direct Observation of the Transition from Indirect to Direct Bandgap in Atomically Thin Epitaxial MoSe2 × You are accessing a document from the Department of Energy's (DOE) SciTech Connect. This site is a product of DOE's Office of Scientific and Technical Information (OSTI) and

  15. NuSTAR Observations of the Bullet Cluster: Constraints on Inverse Compton

    Office of Scientific and Technical Information (OSTI)

    Emission (Journal Article) | SciTech Connect NuSTAR Observations of the Bullet Cluster: Constraints on Inverse Compton Emission Citation Details In-Document Search Title: NuSTAR Observations of the Bullet Cluster: Constraints on Inverse Compton Emission × You are accessing a document from the Department of Energy's (DOE) SciTech Connect. This site is a product of DOE's Office of Scientific and Technical Information (OSTI) and is provided as a public service. Visit OSTI to utilize additional

  16. Determination of E and G Observables in n Photoproduction on the CLAS Frozen Spin Target (FROST)

    SciTech Connect (OSTI)

    Senderovich, Igor; Morrison, Brian T.; Dugger, Michael R.; Ritchie, Barry G.; Tucker, Ross J.

    2014-01-01

    Polarization observables are vital for disentangling overlapping resonances in the baryon spectrum. Extensive data have been collected at Jefferson Lab in Hall B with circularly and linearly polarized tagged photon beam incident on longitudinally polarized protons provided by the Frozen Spin Target (FROST). The focus of the described work is on ? photoproduction, which acts as an "isospin filter", isolating the N*(I = 1/2) resonances. Preliminary results for the double-polarization observables E and G are presented. There are currently no data on these in the world database for ? photoproduction.

  17. Anti-Alpha Particles Observed for the First Time | U.S. DOE Office of

    Office of Science (SC) Website

    Science (SC) 1 » Anti-Alpha Particles Observed for the First Time Nuclear Physics (NP) NP Home About Research Facilities Science Highlights Benefits of NP Funding Opportunities Nuclear Science Advisory Committee (NSAC) Community Resources Contact Information Nuclear Physics U.S. Department of Energy SC-26/Germantown Building 1000 Independence Ave., SW Washington, DC 20585 P: (301) 903-3613 F: (301) 903-3833 E: Email Us More Information » 04.01.11 Anti-Alpha Particles Observed for the First

  18. Fermi Observations of GRB 090510: a Short Hard Gamma-Ray Burst with an

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

    Additional, Hard Power-Law Component from 10 KeV to GeV Energies (Journal Article) | SciTech Connect Observations of GRB 090510: a Short Hard Gamma-Ray Burst with an Additional, Hard Power-Law Component from 10 KeV to GeV Energies Citation Details In-Document Search Title: Fermi Observations of GRB 090510: a Short Hard Gamma-Ray Burst with an Additional, Hard Power-Law Component from 10 KeV to GeV Energies Authors: Ackermann, M. ; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys.

  19. Observation of spin-wave dispersion in Nd-Fe-B magnets using neutron Brillouin scattering

    SciTech Connect (OSTI)

    Ono, K. Inami, N.; Saito, K.; Takeichi, Y.; Kawana, D.; Yokoo, T.; Itoh, S.; Yano, M.; Shoji, T.; Manabe, A.; Kato, A.; Kaneko, Y.

    2014-05-07

    The low-energy spin-wave dispersion in polycrystalline Nd-Fe-B magnets was observed using neutron Brillouin scattering (NBS). Low-energy spin-wave excitations for the lowest acoustic spin-wave mode were clearly observed. From the spin-wave dispersion, we were able to determine the spin-wave stiffness constant D{sub sw} (100.0??4.9?meV.{sup 2}) and the exchange stiffness constant A (6.6 0.3 pJ/m)

  20. Cirrus cloud-temperature interactions over a tropical station, Gadanki from lidar and satellite observations

    SciTech Connect (OSTI)

    S, Motty G Satyanarayana, M. Krishnakumar, V. Dhaman, Reji k.

    2014-10-15

    The cirrus clouds play an important role in the radiation budget of the earth's atmospheric system and are important to characterize their vertical structure and optical properties. LIDAR measurements are obtained from the tropical station Gadanki (13.5{sup 0} N, 79.2{sup 0} E), India, and meteorological indicators derived from Radiosonde data. Most of the cirrus clouds are observed near to the tropopause, which substantiates the strength of the tropical convective processes. The height and temperature dependencies of cloud height, optical depth, and depolarization ratio were investigated. Cirrus observations made using CALIPSO satellite are compared with lidar data for systematic statistical study of cirrus climatology.

  1. Search for Large Extra Dimensions Based on Observations of Neutron Stars

    Office of Scientific and Technical Information (OSTI)

    with the Fermi-LAT (Thesis/Dissertation) | SciTech Connect Thesis/Dissertation: Search for Large Extra Dimensions Based on Observations of Neutron Stars with the Fermi-LAT Citation Details In-Document Search Title: Search for Large Extra Dimensions Based on Observations of Neutron Stars with the Fermi-LAT Large extra dimensions (LED) have been proposed to account for the apparent weakness of gravitation. These theories also indicate that the postulated massive Kaluza-Klein (KK) gravitons may

  2. Symmetry-Breaking Orbital Anisotropy Observed for Detwinned Ba(Fe (1-X) Co

    Office of Scientific and Technical Information (OSTI)

    (X) ) (2) As (2) Above the Spin Density Wave Transition (Journal Article) | SciTech Connect Symmetry-Breaking Orbital Anisotropy Observed for Detwinned Ba(Fe (1-X) Co (X) ) (2) As (2) Above the Spin Density Wave Transition Citation Details In-Document Search Title: Symmetry-Breaking Orbital Anisotropy Observed for Detwinned Ba(Fe (1-X) Co (X) ) (2) As (2) Above the Spin Density Wave Transition Authors: Yi, M. ; Lu, D. ; Chu, J.-H. ; Analytis, J.G. ; Sorini, A.P. ; Kemper, A.F. ; Mortiz, B. ;

  3. Method for determining the octane rating of gasoline samples by observing corresponding acoustic resonances therein

    DOE Patents [OSTI]

    Sinha, D.N.; Anthony, B.W.

    1997-02-25

    A method is described for determining the octane rating of gasoline samples by observing corresponding acoustic resonances therein. A direct correlation between the octane rating of gasoline and the frequency of corresponding acoustic resonances therein has been experimentally observed. Therefore, the octane rating of a gasoline sample can be directly determined through speed of sound measurements instead of by the cumbersome process of quantifying the knocking quality of the gasoline. Various receptacle geometries and construction materials may be employed. Moreover, it is anticipated that the measurements can be performed on flowing samples in pipes, thereby rendering the present method useful in refineries and distilleries. 3 figs.

  4. X-Ray Diffraction Observations of a Charge-Density-Wave Order in

    Office of Scientific and Technical Information (OSTI)

    Superconducting Ortho-II YBa2Cu3O6.54 Single Crystals in Zero Magnetic Field (Journal Article) | SciTech Connect X-Ray Diffraction Observations of a Charge-Density-Wave Order in Superconducting Ortho-II YBa2Cu3O6.54 Single Crystals in Zero Magnetic Field Citation Details In-Document Search Title: X-Ray Diffraction Observations of a Charge-Density-Wave Order in Superconducting Ortho-II YBa2Cu3O6.54 Single Crystals in Zero Magnetic Field Authors: Blackburn, E. ; Chang, J. ; Hücker, M. ;

  5. Observation of multi-scale turbulence and non-local transport in LHD plasmas

    SciTech Connect (OSTI)

    Tokuzawa, T.; Inagaki, S.; Itoh Research Center for Plasma Turbulence, Kyushu University, Kasuga, Fukuoka 816-8580 ; Ida, K.; Itoh, K.; Itoh Research Center for Plasma Turbulence, Kyushu University, Kasuga, Fukuoka 816-8580 ; Ido, T.; Shimizu, A.; Takahashi, H.; Tamura, N.; Yoshinuma, M.; Tsuchiya, H.; Yamada, I.; Tanaka, K.; Akiyama, T.; Nagayama, Y.; Kawahata, K.; Watanabe, K. Y.; Yamada, H.; Kitajima, S.

    2014-05-15

    We have studied two types of spatio-temporal turbulence dynamics in plasmas in the Large Helical Device, based on turbulence measurements with high spatial and temporal resolution. Applying conditional ensemble-averaging to a plasma with Edge-Localized Modes (ELMs), fast radial inward propagation of a micro-scale turbulence front is observed just after ELM event, and the propagation speed is evaluated as ?100?m/s. A self-organized radial electric field structure is observed in an electrode biasing experiment, and it is found to realize a multi-valued state. The curvature of the radial electric field is found to play an important role for turbulence reduction.

  6. High-resolution in situ observations of electron precipitation-causing EMIC waves

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

    Rodger, Craig J.; Hendry, Aaron T.; Clilverd, Mark A.; Kletzing, Craig A.; Brundell, James B.; Reeves, Geoffrey D.

    2015-11-21

    Electromagnetic ion cyclotron (EMIC) waves are thought to be important drivers of energetic electron losses from the outer radiation belt through precipitation into the atmosphere. While the theoretical possibility of pitch angle scattering-driven losses from these waves has been recognized for more than four decades, there have been limited experimental precipitation observations to support this concept. We have combined satellite-based observations of the characteristics of EMIC waves, with satellite and ground-based observations of the EMIC-induced electron precipitation. In a detailed case study, supplemented by an additional four examples, we are able to constrain for the first time the location, size,more » and energy range of EMIC-induced electron precipitation inferred from coincident precipitation data and relate them to the EMIC wave frequency, wave power, and ion band of the wave as measured in situ by the Van Allen Probes. As a result, these observations will better constrain modeling into the importance of EMIC wave-particle interactions.« less

  7. Estimation of the extragalactic background light using TeV observations of BL Lac objects

    SciTech Connect (OSTI)

    Sinha, Atreyee; Acharya, B. S.; Sahayanathan, S.; Godambe, S.; Misra, R. E-mail: acharya@tifr.res.in E-mail: gsagar@barc.ernet.in

    2014-11-01

    The very high-energy (VHE) gamma-ray spectral index of high-energy peaked blazars correlates strongly with its corresponding redshift, whereas no such correlation is observed in the X-ray or GeV bands. We attribute this correlation to photon-photon absorption of TeV photons with the extragalactic background light (EBL), and utilizing this we compute the allowed flux range for the EBL, which is independent of previous estimates. The observed VHE spectrum of the sources in our sample can be well approximated by a power law, and if the de-absorbed spectrum is also assumed to be a power law, then we show that the spectral shape of EBL will be ?n(?) ? klog (?/? {sub p}). We estimate the range of values for the parameters defining the EBL spectrum, k and ? {sub p}, such that the correlation of the intrinsic VHE spectrum with redshift is nullified. The estimated EBL depends only on the observed correlation and the assumption of a power-law source spectrum. Specifically, it does not depend on the spectral modeling or radiative mechanism of the sources or on any theoretical shape of the EBL spectrum obtained through cosmological calculations. The estimated EBL spectrum is consistent with the upper and lower limits imposed by different observations. Moreover, it also agrees closely with the theoretical estimates obtained through cosmological evolution models.

  8. Improving Convection Parameterization Using ARM Observations and NCAR Community Atmosphere Model

    SciTech Connect (OSTI)

    Zhang, Guang J

    2013-07-29

    Highlight of Accomplishments: We made significant contribution to the ASR program in this funding cycle by better representing convective processes in GCMs based on knowledge gained from analysis of ARM/ASR observations. In addition, our work led to a much improved understanding of the interaction among aerosol, convection, clouds and climate in GCMs.

  9. LATE-TIME OBSERVATIONS OF GRB 080319B: JET BREAK, HOST GALAXY, AND ACCOMPANYING SUPERNOVA

    SciTech Connect (OSTI)

    Tanvir, N. R.; O'Brien, P. T.; Wiersema, K.; Starling, R. L. C.; Rol, E.; Levan, A. J.; Svensson, K.; Fruchter, A. S.; Granot, J.; Jakobsson, P.; Fynbo, J.; Hjorth, J.; Curran, P. A.; Burrows, D. N.; Genet, F.

    2010-12-10

    The Swift-discovered GRB 080319B was by far the most distant source ever observed at naked-eye brightness, reaching a peak apparent magnitude of 5.3 at a redshift of z = 0.937. We present our late-time optical (Hubble Space Telescope, Gemini, and Very Large Telescope) and X-ray (Chandra) observations, which confirm that an achromatic break occurred in the power-law afterglow light curve at {approx}11 days post-burst. This most likely indicates that the gamma-ray burst (GRB) outflow was collimated, which for a uniform jet would imply a total energy in the jet E{sub jet} {approx}> 10{sup 52} erg. Our observations also show a late-time excess of red light, which is well explained if the GRB was accompanied by a supernova (SN), similar to those seen in some other long-duration GRBs. The latest observations are dominated by light from the host and show that the GRB took place in a faint dwarf galaxy (r(AB) {approx} 27.0, rest frame M{sub B} {approx} -17.2). This galaxy is small even by the standards of other GRB hosts, which is suggestive of a low-metallicity environment. Intriguingly, the properties of this extreme event-a small host and bright SN-are entirely typical of the very low luminosity bursts such as GRB 980425 and GRB 060218.

  10. High-resolution in situ observations of electron precipitation-causing EMIC waves

    SciTech Connect (OSTI)

    Rodger, Craig J.; Hendry, Aaron T.; Clilverd, Mark A.; Kletzing, Craig A.; Brundell, James B.; Reeves, Geoffrey D.

    2015-11-21

    Electromagnetic ion cyclotron (EMIC) waves are thought to be important drivers of energetic electron losses from the outer radiation belt through precipitation into the atmosphere. While the theoretical possibility of pitch angle scattering-driven losses from these waves has been recognized for more than four decades, there have been limited experimental precipitation observations to support this concept. We have combined satellite-based observations of the characteristics of EMIC waves, with satellite and ground-based observations of the EMIC-induced electron precipitation. In a detailed case study, supplemented by an additional four examples, we are able to constrain for the first time the location, size, and energy range of EMIC-induced electron precipitation inferred from coincident precipitation data and relate them to the EMIC wave frequency, wave power, and ion band of the wave as measured in situ by the Van Allen Probes. As a result, these observations will better constrain modeling into the importance of EMIC wave-particle interactions.

  11. INTERACTIONS BETWEEN CORONAL MASS EJECTIONS VIEWED IN COORDINATED IMAGING AND IN SITU OBSERVATIONS

    SciTech Connect (OSTI)

    Liu, Ying D.; Luhmann, Janet G.; Moestl, Christian; Martinez-Oliveros, Juan C.; Bale, Stuart D.; Lin, Robert P.; Harrison, Richard A.; Temmer, Manuela; Webb, David F.; Odstrcil, Dusan

    2012-02-20

    The successive coronal mass ejections (CMEs) from 2010 July 30 to August 1 present us the first opportunity to study CME-CME interactions with unprecedented heliospheric imaging and in situ observations from multiple vantage points. We describe two cases of CME interactions: merging of two CMEs launched close in time and overtaking of a preceding CME by a shock wave. The first two CMEs on August 1 interact close to the Sun and form a merged front, which then overtakes the July 30 CME near 1 AU, as revealed by wide-angle imaging observations. Connections between imaging observations and in situ signatures at 1 AU suggest that the merged front is a shock wave, followed by two ejecta observed at Wind which seem to have already merged. In situ measurements show that the CME from July 30 is being overtaken by the shock at 1 AU and is significantly compressed, accelerated, and heated. The interaction between the preceding ejecta and shock also results in variations in the shock strength and structure on a global scale, as shown by widely separated in situ measurements from Wind and STEREO B. These results indicate important implications of CME-CME interactions for shock propagation, particle acceleration, and space weather forecasting.

  12. Charge state evolution in the solar wind. III. Model comparison with observations

    SciTech Connect (OSTI)

    Landi, E.; Oran, R.; Lepri, S. T.; Zurbuchen, T. H.; Fisk, L. A.; Van der Holst, B.

    2014-08-01

    We test three theoretical models of the fast solar wind with a set of remote sensing observations and in-situ measurements taken during the minimum of solar cycle 23. First, the model electron density and temperature are compared to SOHO/SUMER spectroscopic measurements. Second, the model electron density, temperature, and wind speed are used to predict the charge state evolution of the wind plasma from the source regions to the freeze-in point. Frozen-in charge states are compared with Ulysses/SWICS measurements at 1 AU, while charge states close to the Sun are combined with the CHIANTI spectral code to calculate the intensities of selected spectral lines, to be compared with SOHO/SUMER observations in the north polar coronal hole. We find that none of the theoretical models are able to completely reproduce all observations; namely, all of them underestimate the charge state distribution of the solar wind everywhere, although the levels of disagreement vary from model to model. We discuss possible causes of the disagreement, namely, uncertainties in the calculation of the charge state evolution and of line intensities, in the atomic data, and in the assumptions on the wind plasma conditions. Last, we discuss the scenario where the wind is accelerated from a region located in the solar corona rather than in the chromosphere as assumed in the three theoretical models, and find that a wind originating from the corona is in much closer agreement with observations.

  13. Six- and three-hourly meteorological observations from 223 USSR stations

    SciTech Connect (OSTI)

    Razuvaev, V.N.; Apasova, E.B.; Martuganov, R.A.; Kaiser, D.P.

    1995-04-01

    This document describes a database containing 6- and 3-hourly meteorological observations from a 223-station network of the former Soviet Union. These data have been made available through cooperation between the two principal climate data centers of the United States and Russia: the National Climatic Data Center (NCDC), in Asheville, North Carolina, and the All-Russian Research Institute of Hydrometeorological Information -- World Data Centre (RIHMI-WDC) in Obninsk. Station records consist of 6- and 3-hourly observations of some 24 meteorological variables including temperature, weather type, precipitation amount, cloud amount and type, sea level pressure, relative humidity, and wind direction and speed. The 6-hourly observations extend from 1936 to 1965; the 3-hourly observations extend from 1966 through the mid-1980s (1983, 1984, 1985, or 1986; depending on the station). These data have undergone extensive quality assurance checks by RIHMI-WDC, NCDC, and the Carbon Dioxide Information Analysis Center (CDIAC). The database represents a wealth of meteorological information for a large and climatologically important portion of the earth`s land area, and should prove extremely useful for a wide variety of regional climate change studies. These data are available free of charge as a numeric data package (NDP) from CDIAC. The NDP consists of this document and 40 data files that are available via the Internet or on 8mm tape. The total size of the database is {approximately}2.6 gigabytes.

  14. OBSERVATIONS OF OUTFLOWING ULTRAVIOLET ABSORBERS IN NGC 4051 WITH THE COSMIC ORIGINS SPECTROGRAPH

    SciTech Connect (OSTI)

    Kraemer, S. B. [Institute for Astrophysics and Computational Sciences, Department of Physics, Catholic University of America, Washington, DC 20064 (United States); Crenshaw, D. M.; Fischer, T. C. [Department of Physics and Astronomy, Georgia State University, Astronomy Offices, One Park Place South SE, Suite 700, Atlanta, GA 30303 (United States); Dunn, J. P. [Department of Chemistry and Physics, Augusta State University, 2500 Walton Way, Augusta, GA 30904 (United States); Turner, T. J. [Department of Physics, University of Maryland Baltimore County, Baltimore, MD 21250 (United States); Lobban, A. P.; Reeves, J. N. [Astrophysics Group, School of Physical and Geographical Sciences, Keele University, Keele, Staffordshire ST5 5BG (United Kingdom); Miller, L. [Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); Braito, V., E-mail: steven.b.kraemer@nasa.gov [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom)

    2012-06-01

    We present new Hubble Space Telescope (HST)/Cosmic Origins Spectrograph (COS) observations of the narrow-line Seyfert 1 galaxy NGC 4051. These data were obtained as part of a coordinated observing program including X-ray observations with the Chandra/High Energy Transmission Grating (HETG) spectrometer and Suzaku. We detected nine kinematic components of UV absorption, which were previously identified using the HST/Space Telescope Imaging Spectrograph (STIS). None of the absorption components showed evidence for changes in column density or profile within the {approx}10 yr between the STIS and COS observations, which we interpret as evidence of (1) saturation, for the stronger components, or (2) very low densities, i.e., n{sub H} < 1 cm{sup -3}, for the weaker components. After applying a +200 km s{sup -1} offset to the HETG spectrum, we found that the radial velocities of the UV absorbers lay within the O VII profile. Based on photoionization models, we suggest that, while UV components 2, 5, and 7 produce significant O VII absorption, the bulk of the X-ray absorption detected in the HETG analysis occurs in more highly ionized gas. Moreover, the mass-loss rate is dominated by high-ionization gas which lacks a significant UV footprint.

  15. CARMA LARGE AREA STAR FORMATION SURVEY: OBSERVATIONAL ANALYSIS OF FILAMENTS IN THE SERPENS SOUTH MOLECULAR CLOUD

    SciTech Connect (OSTI)

    Fernndez-Lpez, M.; Looney, L.; Lee, K.; Segura-Cox, D.; Arce, H. G.; Plunkett, A.; Mundy, L. G.; Storm, S.; Teuben, P. J.; Pound, M.; Isella, A.; Kauffmann, J.; Tobin, J. J.; Rosolowsky, E.; Kwon, W.; Ostriker, E.; Tassis, K.; Shirley, Y. L.

    2014-08-01

    We present the N{sub 2}H{sup +} (J = 1 ? 0) map of the Serpens South molecular cloud obtained as part of the CARMA Large Area Star Formation Survey. The observations cover 250 arcmin{sup 2} and fully sample structures from 3000 AU to 3pc with a velocity resolution of 0.16kms{sup 1}, and they can be used to constrain the origin and evolution of molecular cloud filaments. The spatial distribution of the N{sub 2}H{sup +} emission is characterized by long filaments that resemble those observed in the dust continuum emission by Herschel. However, the gas filaments are typically narrower such that, in some cases, two or three quasi-parallel N{sub 2}H{sup +} filaments comprise a single observed dust continuum filament. The difference between the dust and gas filament widths casts doubt on Herschel ability to resolve the Serpens South filaments. Some molecular filaments show velocity gradients along their major axis, and two are characterized by a steep velocity gradient in the direction perpendicular to the filament axis. The observed velocity gradient along one of these filaments was previously postulated as evidence for mass infall toward the central cluster, but these kind of gradients can be interpreted as projection of large-scale turbulence.

  16. The Radiative Properties of Small Clouds: Multi-Scale Observations and Modeling

    SciTech Connect (OSTI)

    Feingold, Graham; McComiskey, Allison

    2013-09-25

    Warm, liquid clouds and their representation in climate models continue to represent one of the most significant unknowns in climate sensitivity and climate change. Our project combines ARM observations, LES modeling, and satellite imagery to characterize shallow clouds and the role of aerosol in modifying their radiative effects.

  17. X-ray observations of complex temperature structure in the cool-core cluster A85

    SciTech Connect (OSTI)

    Schenck, David E.; Datta, Abhirup; Burns, Jack O.; Skillman, Sam

    2014-07-01

    X-ray observations were used to examine the complex temperature structure of A85, a cool-core galaxy cluster. Temperature features can provide evidence of merging events which shock heat the intracluster gas. Temperature maps were made from both Chandra and XMM-Newton observations. The combination of a new, long-exposure XMM observation and an improved temperature map binning technique produced the highest fidelity temperature maps of A85 to date. Hot regions were detected near the subclusters to the south and southwest in both the Chandra and XMM temperature maps. The presence of these structures implies A85 is not relaxed. The hot regions may indicate the presence of shocks. The Mach numbers were estimated to be ?1.9 at the locations of the hot spots. Observational effects will tend to systematically reduce temperature jumps, so the measured Mach numbers are likely underestimated. Neither temperature map showed evidence for a shock in the vicinity of the presumed radio relic near the southwest subcluster. However, the presence of a weak shock cannot be ruled out. There was tension between the temperatures measured by the two instruments.

  18. Real time synchrotron X-ray observations of solidification in hypoeutectic AlSi alloys

    SciTech Connect (OSTI)

    Nogita, Kazuhiro [Nihon Superior Centre for the Manufacture of Electronic Materials, The University of Queensland, Brisbane, QLD 4072 (Australia); School of Mechanical and Mining Engineering, The University of Queensland, Brisbane, QLD 4072 (Australia); Yasuda, Hideyuki [Department of Adaptive Machine Systems, Osaka University, Suita, Osaka, 565-0871 (Japan); Prasad, Arvind [School of Mechanical and Mining Engineering, The University of Queensland, Brisbane, QLD 4072 (Australia); McDonald, Stuart D., E-mail: s.mcdonald1@uq.edu.au [Nihon Superior Centre for the Manufacture of Electronic Materials, The University of Queensland, Brisbane, QLD 4072 (Australia); School of Mechanical and Mining Engineering, The University of Queensland, Brisbane, QLD 4072 (Australia); Nagira, Tomoya; Nakatsuka, Noriaki [Department of Adaptive Machine Systems, Osaka University, Suita, Osaka, 565-0871 (Japan); Uesugi, Kentaro [Japan Synchrotron Radiation Research Institute, SPring-8, Sayo, Hyogo, 679-5198 (Japan); StJohn, David H. [School of Mechanical and Mining Engineering, The University of Queensland, Brisbane, QLD 4072 (Australia)

    2013-11-15

    This paper demonstrates how recent advances in synchrotron technology have allowed for the real-time X-ray imaging of solidification in AlSi alloys, despite the small difference in atomic number of these elements. The experiments performed at the SPring-8 synchrotron, involved imaging the solidification of Al1wt.%Si and Al4wt.%Si alloys under a low-temperature gradient and a cooling rate of around 0.3 C/s. The nucleation and growth of the primary aluminum grains as well as the onset of eutectic solidification were clearly observed. In the alloys containing Al4wt.%Si, contrast was sufficient to characterize the nucleation rate and growth velocity of the aluminum grains. The importance of improving observation of solidification in the AlSi system by increasing the time resolution during critical events is discussed. - Highlights: A synchrotron technique was used to observe solidification of Al-Si alloys. Nucleation, coarsening, and the onset of eutectic solidification were observed. Images captured are suitable for quantitative analysis. The resolution that was obtained should be possible for most aluminum alloys.

  19. Observation of ?-vibrations and alignments built on non-ground-state configurations in ??Dy

    SciTech Connect (OSTI)

    Zhu, C. -H.; Hartley, D. J.; Riedinger, L. L.; Sharpey-Schafer, J. F.; Almond, J. M.; Beausang, C.; Carpenter, M. P.; Chiara, C. J.; Cooper, N.; Curien, D.; Gall, B. J. P.; Garrett, P. E.; Janssens, R. V. F.; Kondev, F. G.; Kulp, W. D.; Lauritsen, T.; McCutchan, E. A.; Miller, D.; Piot, J.; Redon, N.; Riley, M. A.; Simpson, J.; Stefanescu, I.; Werner, V.; Wang, X.; Wood, J. L.; Majola, S. N. T.; Zhu, S.

    2015-03-26

    The exact nature of the lowest K?=2? rotational bands in all deformed nuclei remains obscure. Traditionally they are assumed to be collective vibrations of the nuclear shape in the ? degree of freedom perpendicular to the nuclear symmetry axis. Very few such ?-bands have been traced past the usual back-bending rotational alignments of high-j nucleons. We have investigated the structure of positive-parity bands in the N=90 nucleus ??Dy, using the ??Nd(C,4n)??Dy reaction at 65 MeV, observing the resulting ?-ray transitions with the Gammasphere array. The even- and odd-spin members of the ?=2? ?-band are observed to 32? and 31? respectively. This rotational band faithfully tracks the ground-state configuration to the highest spins. The members of a possible ?-vibration built on the aligned yrast S-band are observed to spins 28? and 27?. An even-spin positive-parity band, observed to spin 24?, is a candidate for an aligned S-band built on the seniority-zero configuration of the 0?? state at 676 keV. As a result, the crossing of this band with the 0?? band is at hwc = 0.28(1) MeV and is consistent with the configuration of the 0?? band not producing any blocking of the monopole pairing.

  20. Detection of the Cosmic ?-Ray Horizon From Multiwavelength Observations of Blazars

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

    Dominguez, A.; Finke, J. D.; Prada, F.; Primack, J. R.; Kitaura, F. S.; Siana, B.; Paneque, D.

    2013-05-24

    The first statistically significant detection of the cosmic ?-ray horizon (CGRH) that is independent of any extragalactic background light (EBL) model is presented. The CGRH is a fundamental quantity in cosmology. It gives an estimate of the opacity of the Universe to very high energy (VHE) ?-ray photons due to photon-photon pair production with the EBL. The only estimations of the CGRH to date are predictions from EBL models and lower limits from ?-ray observations of cosmological blazars and ?-ray bursts. Here, we present homogeneous synchrotron/synchrotron self-Compton (SSC) models of the spectral energy distributions of 15 blazars based on (almost)moresimultaneous observations from radio up to the highest energy ?-rays taken with the Fermi satellite. These synchrotron/SSC models predict the unattenuated VHE fluxes, which are compared with the observations by imaging atmospheric Cherenkov telescopes. This comparison provides an estimate of the optical depth of the EBL, which allows a derivation of the CGRH through a maximum likelihood analysis that is EBL-model independent. We find that the observed CGRH is compatible with the current knowledge of the EBL.less

  1. Emergence of granular-sized magnetic bubbles through the solar atmosphere. I. Spectropolarimetric observations and simulations

    SciTech Connect (OSTI)

    Ortiz, Ada; Hansteen, Viggo H.; Van der Voort, Luc Rouppe [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, N-0315 Oslo (Norway); Bellot Rubio, Luis R. [Instituto de Astrofsica de Andaluca (CSIC), Apdo. 3040, E-18080 Granada (Spain); De la Cruz Rodrguez, Jaime, E-mail: ada@astro.uio.no [Department of Physics and Astronomy, Uppsala University, Box 516, SE-75120 Uppsala (Sweden)

    2014-02-01

    We study a granular-sized magnetic flux emergence event that occurred in NOAA 11024 in 2009 July. The observations were made with the CRISP spectropolarimeter at the Swedish 1 m Solar Telescope achieving a spatial resolution of 0.''14. Simultaneous full Stokes observations of the two photospheric Fe I lines at 630.2 nm and the chromospheric Ca II 854.2 nm line allow us to describe in detail the emergence process across the solar atmosphere. We report here on three-dimensional (3D) semi-spherical bubble events, where instead of simple magnetic footpoints, we observe complex semi-circular feet straddling a few granules. Several phenomena occur simultaneously, namely, abnormal granulation, separation of opposite-polarity legs, and brightenings at chromospheric heights. However, the most characteristic signature in these events is the observation of a dark bubble in filtergrams taken in the wings of the Ca II 854.2 nm line. There is a clear coincidence between the emergence of horizontal magnetic field patches and the formation of the dark bubble. We can infer how the bubble rises through the solar atmosphere as we see it progressing from the wings to the core of Ca II 854.2 nm. In the photosphere, the magnetic bubble shows mean upward Doppler velocities of 2 km s{sup 1} and expands at a horizontal speed of 4 km s{sup 1}. In about 3.5 minutes it travels some 1100 km to reach the mid chromosphere, implying an average ascent speed of 5.2 km s{sup 1}. The maximum separation attained by the magnetic legs is 6.''6. From an inversion of the observed Stokes spectra with the SIR code, we find maximum photospheric field strengths of 480 G and inclinations of nearly 90 in the magnetic bubble interior, along with temperature deficits of up to 250 K at log ? = 2 and above. To aid the interpretation of the observations, we carry out 3D numerical simulations of the evolution of a horizontal, untwisted magnetic flux sheet injected in the convection zone, using the Bifrost code. The computational domain spans from the upper convection zone to the lower corona. In the modeled chromosphere, the rising flux sheet produces a large, cool, magnetized bubble. We compare this bubble with the observed ones and find excellent agreement, including similar field strengths and velocity signals in the photosphere and chromosphere, temperature deficits, ascent speeds, expansion velocities, and lifetimes.

  2. Mapping and Simulating Systematics Due to Spatially-Varying Observing Conditions in DES Science Verification Data

    SciTech Connect (OSTI)

    Leistedt, B.

    2015-07-20

    Spatially-varying depth and characteristics of observing conditions, such as seeing, airmass, or sky background, are major sources of systematic uncertainties in modern galaxy survey analyses, in particular in deep multi-epoch surveys. We present a framework to extract and project these sources of systematics onto the sky, and apply it to the Dark Energy Survey (DES) to map the observing conditions of the Science Verification (SV) data. The resulting distributions and maps of sources of systematics are used in several analyses of DES SV to perform detailed null tests with the data, and also to incorporate systematics in survey simulations. We illustrate the complementarity of these two approaches by comparing the SV data with the BCC-UFig, a synthetic sky catalogue generated by forward-modelling of the DES SV images. We then analyse the BCC-UFig simulation to construct galaxy samples mimicking those used in SV galaxy clustering studies. We show that the spatially-varying survey depth imprinted in the observed galaxy densities and the redshift distributions of the SV data are successfully reproduced by the simulation and well-captured by the maps of observing conditions. The combined use of the maps, the SV data and the BCC-UFig simulation allows us to quantify the impact of spatial systematics on N(z), the redshift distributions inferred using photometric redshifts. We conclude that spatial systematics in the SV data are mainly due to seeing fluctuations and are under control in current clustering and weak lensing analyses. However, they will need to be carefully characterised in upcoming phases of DES in order to avoid biasing the inferred cosmological results. The framework presented is relevant to all multi-epoch surveys, and will be essential for exploiting future surveys such as the Large Synoptic Survey Telescope, which will require detailed null-tests and realistic end-to-end image simulations to correctly interpret the deep, high-cadence observations of the sky.

  3. Energetic electron precipitation associated with pulsating aurora: EISCAT and Van Allen Probe observations

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

    Miyoshi, Y.; Oyama, S.; Saito, S.; Kurita, S.; Fujiwara, H.; Kataoka, R.; Ebihara, Y.; Kletzing, C.; Reeves, G.; Santolik, O.; et al

    2015-04-21

    Pulsating auroras show quasi-periodic intensity modulations caused by the precipitation of energetic electrons of the order of tens of keV. It is expected theoretically that not only these electrons but also subrelativistic/relativistic electrons precipitate simultaneously into the ionosphere owing to whistler mode wave-particle interactions. The height-resolved electron density profile was observed with the European Incoherent Scatter (EISCAT) Tromsø VHF radar on 17 November 2012. Electron density enhancements were clearly identified at altitudes >68 km in association with the pulsating aurora, suggesting precipitation of electrons with a broadband energy range from ~10 keV up to at least 200 keV. The riometermore » and network of subionospheric radio wave observations also showed the energetic electron precipitations during this period. During this period, the footprint of the Van Allen Probe-A satellite was very close to Tromsø and the satellite observed rising tone emissions of the lower band chorus (LBC) waves near the equatorial plane. Considering the observed LBC waves and electrons, we conducted a computer simulation of the wave-particle interactions. This showed simultaneous precipitation of electrons at both tens of keV and a few hundred keV, which is consistent with the energy spectrum estimated by the inversion method using the EISCAT observations. This result revealed that electrons with a wide energy range simultaneously precipitate into the ionosphere in association with the pulsating aurora, providing the evidence that pulsating auroras are caused by whistler chorus waves. We suggest that scattering by propagating whistler simultaneously causes both the precipitations of subrelativistic electrons and the pulsating aurora.« less

  4. PARTICLE ACCELERATION AT QUASI-PARALLEL SHOCK WAVES: THEORY AND OBSERVATIONS AT 1 AU

    SciTech Connect (OSTI)

    Neergaard Parker, L.; Zank, G. P.

    2012-09-20

    In this paper, we describe a theoretical model for accelerating an arbitrary upstream particle distribution. Only those particles that exceed a prescribed injection energy, E{sub inj}, are accelerated via the diffusive shock acceleration (DSA) mechanism, also known as first-order Fermi acceleration. We identify a set of quasi-parallel shocks at 1 AU and use the observed solar wind particle distribution information to construct our upstream distribution, which is then accelerated diffusively at the shock, assuming the observed shock parameters. The injection energy for particles to be accelerated diffusively at a quasi-parallel shock is discussed theoretically. By using the observed upstream solar wind distribution function and the observed shock parameters, we can compute the injection energy that matches the observed downstream accelerated particle spectrum. Like the previous studies of van Nes et al., Lario et al., and Ho et al., this analysis focuses on the acceleration of protons only via the first-order Fermi acceleration mechanism. However, our primary focus is on quasi-parallel shocks and the injection mechanism in the context of DSA with a background thermal solar wind modeled as a Maxwellian or kappa distribution. Our approach allows for a direct test of injection at interplanetary shocks. It has been proposed that an additional seed population of energetic particles is needed to explain the accelerated particle distribution downstream of quasi-parallel shocks. This conclusion is based typically on studies that address the acceleration of heavy ions primarily and do not characterize the injection of protons alone using the DSA mechanism. Through comparisons of Maxwellian and kappa upstream distributions, we find that DSA with injection directly from a thermal Maxwellian distribution, or weak departures therefrom, for protons is responsible for energetic solar particle events associated with quasi-parallel shocks.

  5. Energetic electron precipitation associated with pulsating aurora: EISCAT and Van Allen Probe observations

    SciTech Connect (OSTI)

    Miyoshi, Y.; Oyama, S.; Saito, S.; Kurita, S.; Fujiwara, H.; Kataoka, R.; Ebihara, Y.; Kletzing, C.; Reeves, G.; Santolik, O.; Clilverd, M.; Rodger, C. J.; Turunen, E.; Tsuchiya, F.

    2015-04-21

    Pulsating auroras show quasi-periodic intensity modulations caused by the precipitation of energetic electrons of the order of tens of keV. It is expected theoretically that not only these electrons but also subrelativistic/relativistic electrons precipitate simultaneously into the ionosphere owing to whistler mode wave-particle interactions. The height-resolved electron density profile was observed with the European Incoherent Scatter (EISCAT) Troms VHF radar on 17 November 2012. Electron density enhancements were clearly identified at altitudes >68 km in association with the pulsating aurora, suggesting precipitation of electrons with a broadband energy range from ~10 keV up to at least 200 keV. The riometer and network of subionospheric radio wave observations also showed the energetic electron precipitations during this period. During this period, the footprint of the Van Allen Probe-A satellite was very close to Troms and the satellite observed rising tone emissions of the lower band chorus (LBC) waves near the equatorial plane. Considering the observed LBC waves and electrons, we conducted a computer simulation of the wave-particle interactions. This showed simultaneous precipitation of electrons at both tens of keV and a few hundred keV, which is consistent with the energy spectrum estimated by the inversion method using the EISCAT observations. This result revealed that electrons with a wide energy range simultaneously precipitate into the ionosphere in association with the pulsating aurora, providing the evidence that pulsating auroras are caused by whistler chorus waves. We suggest that scattering by propagating whistler simultaneously causes both the precipitations of subrelativistic electrons and the pulsating aurora.

  6. Understanding and Improving CRM and GCM Simulations of Cloud Systems with ARM Observations

    SciTech Connect (OSTI)

    Wu, Xiaoqing

    2014-02-25

    The works supported by this ASR project lay the solid foundation for improving the parameterization of convection and clouds in the NCAR CCSM and the climate simulations. We have made a significant use of CRM simulations and ARM observations to produce thermodynamically and dynamically consistent multi-year cloud and radiative properties; improve the GCM simulations of convection, clouds and radiative heating rate and fluxes using the ARM observations and CRM simulations; and understand the seasonal and annual variation of cloud systems and their impacts on climate mean state and variability. We conducted multi-year simulations over the ARM SGP site using the CRM with multi-year ARM forcing data. The statistics of cloud and radiative properties from the long-term CRM simulations were compared and validated with the ARM measurements and value added products (VAP). We evaluated the multi-year climate simulations produced by the GCM with the modified convection scheme. We used multi-year ARM observations and CRM simulations to validate and further improve the trigger condition and revised closure assumption in NCAR GCM simulations that demonstrate the improvement of climate mean state and variability. We combined the improved convection scheme with the mosaic treatment of subgrid cloud distributions in the radiation scheme of the GCM. The mosaic treatment of cloud distributions has been implemented in the GCM with the original convection scheme and enables the use of more realistic cloud amounts as well as cloud water contents in producing net radiative fluxes closer to observations. A physics-based latent heat (LH) retrieval algorithm was developed by parameterizing the physical linkages of observed hydrometeor profiles of cloud and precipitation to the major processes related to the phase change of atmospheric water.

  7. VLBA AND CHANDRA OBSERVATIONS OF JETS IN FRI RADIO GALAXIES: CONSTRAINTS ON JET EVOLUTION

    SciTech Connect (OSTI)

    Kharb, P.; O'Dea, C. P.; Tilak, A.; Baum, S. A.; Haynes, E.; Noel-Storr, J.; Fallon, C.; Christiansen, K.

    2012-07-20

    We present here the results from new Very Long Baseline Array (VLBA) observations at 1.6 and 5 GHz of 19 galaxies of a complete sample of 21 Uppasala General Catalog (UGC) Fanaroff-Riley type I (FRI) radio galaxies. New Chandra data of two sources, viz., UGC 00408 and UGC 08433, are combined with the Chandra archival data of 13 sources. The 5 GHz observations of 10 'core-jet' sources are polarization-sensitive, while the 1.6 GHz observations constitute second-epoch total intensity observations of nine 'core-only' sources. Polarized emission is detected in the jets of seven sources at 5 GHz, but the cores are essentially unpolarized, except in M87. Polarization is detected at the jet edges in several sources, and the inferred magnetic field is primarily aligned with the jet direction. This could be indicative of magnetic field 'shearing' due to jet-medium interaction, or the presence of helical magnetic fields. The jet peak intensity I{sub {nu}} falls with distance d from the core, following the relation, I{sub {nu}}{proportional_to}d{sup a} , where a is typically {approx} - 1.5. Assuming that adiabatic expansion losses are primarily responsible for the jet intensity 'dimming,' two limiting cases are considered: (1) the jet has a constant speed on parsec scales and is expanding gradually such that the jet radius r{proportional_to}d 0{sup .4}; this expansion is, however, unobservable in the laterally unresolved jets at 5 GHz, and (2) the jet is cylindrical and is accelerating on parsec scales. Accelerating parsec-scale jets are consistent with the phenomenon of 'magnetic driving' in Poynting-flux-dominated jets. While slow jet expansion as predicted by case (1) is indeed observed in a few sources from the literature that are resolved laterally, on scales of tens or hundreds of parsecs, case (2) cannot be ruled out in the present data, provided the jets become conical on scales larger than those probed by VLBA. Chandra observations of 15 UGC FRIs detect X-ray jets in 9 of them. The high frequency of occurrence of X-ray jets in this complete sample suggests that they are a signature of a ubiquitous process in FRI jets. It appears that the FRI jets start out relativistically on parsec scales but decelerate on kiloparsec scales, with the X-ray emission revealing the sites of bulk deceleration and particle reacceleration.

  8. Observational constraints on dark energy with a fast varying equation of state

    SciTech Connect (OSTI)

    Felice, Antonio De; Nesseris, Savvas

    2012-05-01

    We place observational constraints on models with the late-time cosmic acceleration based on a number of parametrizations allowing fast transitions for the equation of state of dark energy. In addition to the model of Linder and Huterer where the dark energy equation of state w monotonically grows or decreases in time, we propose two new parametrizations in which w has an extremum. We carry out the likelihood analysis with the three parametrizations by using the observational data of supernovae type Ia, cosmic microwave background, and baryon acoustic oscillations. Although the transient cosmic acceleration models with fast transitions can give rise to the total chi square smaller than that in the ?-Cold-Dark-Matter (?CDM) model, these models are not favored over ?CDM when one uses the Akaike information criterion which penalizes the extra degrees of freedom present in the parametrizations.

  9. Observations of the frequency tuning effect in the 14 GHz CAPRICE ion source

    SciTech Connect (OSTI)

    Celona, L.; Ciavola, G.; Consoli, F.; Gammino, S.; Maimone, F.; Mascali, D.; Spaedtke, P.; Tinschert, K.; Lang, R.; Maeder, J.; Rossbach, J.; Barbarino, S.; Catalano, R. S.

    2008-02-15

    A set of measurements with the CAPRICE ion source at the GSI test bench has been carried out to investigate its behavior in terms of intensity and shape of the extracted beam when the microwaves generating the plasma sweep in a narrow range of frequency ({+-}40 MHz) around the klystron center frequency (14.5 GHz). Remarkable variations have been observed depending on the source and the beamline operating parameters, confirming that a frequency dependent electromagnetic distribution is preserved even in the presence of plasma inside the source. Moreover, these observations confirm that the frequency tuning is a powerful method to optimize the electron cyclotron resonance ion source performances. A description of the experimental setup and of the obtained results is given in the following.

  10. Observational characteristics of coronal mass ejections without low-coronal signatures

    SciTech Connect (OSTI)

    D'Huys, E.; Seaton, D. B.; Berghmans, D.; Poedts, S.

    2014-11-01

    Solar eruptions are usually associated with a variety of phenomena occurring in the low corona before, during, and after the onset of eruption. Though easily visible in coronagraph observations, so-called stealth coronal mass ejections (CMEs) do not obviously exhibit any of these low-coronal signatures. The presence or absence of distinct low-coronal signatures can be linked to different theoretical models to establish the mechanisms by which the eruption is initiated and driven. In this study, 40 CMEs without low-coronal signatures occurring in 2012 are identified. Their observational and kinematic properties are analyzed and compared to those of regular CMEs. Solar eruptions without clear on-disk or low-coronal signatures can lead to unexpected space weather impacts, since many early warning signs for significant space weather activity are not present in these events. A better understanding of their initiation mechanism(s) will considerably improve the ability to predict such space weather events.

  11. High resolution transmission electron microscopic in-situ observations of plastic deformation of compressed nanocrystalline gold

    SciTech Connect (OSTI)

    Wang, Guoyong; Lian, Jianshe; Jiang, Qing; Sun, Sheng; Zhang, Tong-Yi

    2014-09-14

    Nanocrystalline (nc) metals possess extremely high strength, while their capability to deform plastically has been debated for decades. Low ductility has hitherto been considered an intrinsic behavior for most nc metals, due to the lack of five independent slip systems actively operating during deformation in each nanograin. Here we report in situ high resolution transmission electron microscopic (HRTEM) observations of deformation process of nc gold under compression, showing the excellent ductility of individual and aggregate nanograins. Compression causes permanent change in the profile of individual nanograins, which is mediated by dislocation slip and grain rotation. The high rate of grain boundary sliding and large extent of widely exited grain rotation may meet the boundary compatibility requirements during plastic deformation. The in situ HRTEM observations suggest that nc gold is not intrinsically brittle under compressive loading.

  12. A comparison of water vapor quantities from model short-range forecasts and ARM observations

    SciTech Connect (OSTI)

    Hnilo, J J

    2006-03-17

    Model evolution and improvement is complicated by the lack of high quality observational data. To address a major limitation of these measurements the Atmospheric Radiation Measurement (ARM) program was formed. For the second quarter ARM metric we will make use of new water vapor data that has become available, and called the 'Merged-sounding' value added product (referred to as OBS, within the text) at three sites: the North Slope of Alaska (NSA), Darwin Australia (DAR) and the Southern Great Plains (SGP) and compare these observations to model forecast data. Two time periods will be analyzed March 2000 for the SGP and October 2004 for both DAR and NSA. The merged-sounding data have been interpolated to 37 pressure levels (e.g., from 1000hPa to 100hPa at 25hPa increments) and time averaged to 3 hourly data for direct comparison to our model output.

  13. Voyager 2 observations of plasmas and flows out to 104 AU

    SciTech Connect (OSTI)

    Richardson, J. D.; Decker, R. B. E-mail: robert.decker@apljhu.edu

    2014-09-10

    Voyager 2 has crossed through 20 AU of the heliosheath; assuming the same heliosheath thickness as at Voyager 1, it is now two-thirds of the way to the heliopause. The plasma data are generally of good quality, although the increasing flow angle of the plasma makes analysis more difficult. The average plasma speed has remained constant but the flow angles have increased to almost 60 in the RT plane and to almost 30 in the RN plane. The average density and thermal speed have been constant since a density increase observed in 2011. Comparison of V2 plasma flows derived from plasma science experiment (PLS) data and Low Energy Charged Particle (LECP) proton anisotropies give good agreement except when heavy ion contributions or non-convective proton anisotropies are observed in the LECP data.

  14. Tidal disruptions in circumbinary disks. II. Observational signatures in the reverberation spectra

    SciTech Connect (OSTI)

    Brem, P.; Amaro-Seoane, P.; Cuadra, J.; Komossa, S.

    2014-09-10

    Supermassive binary black holes (SMBBHs) with sub-pc separations form in the course of galaxy mergers, if both galaxies harbor massive black holes. Clear observational evidence for them however still eludes us. We propose a novel method of identifying these systems by means of reverberation mapping their circumbinary disk after a tidal disruption event has ionized it. The tidal disruption of a star at the secondary leads to strong asymmetries in the disk response. We model the shape of the velocity-delay maps for various toy disk models and more realistic gas distributions obtained by smoothed particle hydrodynamics simulations. The emissivity of the ionized disk is calculated with Cloudy. We find peculiar asymmetries in the maps for off center ionizing sources that may help us constrain geometrical parameters of a circumbinary disk such as semimajor axis and orbital phase of the secondary, as well as help strengthen the observational evidence for sub-parsec SMBBHs as such.

  15. Observation of dust torus with poloidal rotation in direct current glow discharge plasma

    SciTech Connect (OSTI)

    Kaur, Manjit Bose, Sayak; Chattopadhyay, P. K. Sharma, Devendra; Ghosh, J.; Saxena, Y. C.

    2015-03-15

    Observation of dust cloud rotation in parallel-plate DC glow discharge plasma is reported here. The experiments are carried out at high pressures (∼130 Pa) with a metallic ring placed on the lower electrode (cathode). The dust cloud rotates poloidally in the vertical plane near the cathode surface. This structure is continuous toroidally. Absence of magnetic field rules out the possibility of E × B induced ion flow as the cause of dust rotation. The dust rotational structures exist even with water cooled cathode. Therefore, temperature gradient driven mechanisms, such as thermophoretic force, thermal creep flow, and free convection cannot be causing the observed dust rotation. Langmuir probe measurement reveals the existence of a sharp density gradient near the location of the rotating dust cloud. The gradient in the density, giving rise to a gradient in the ion drag force, has been identified as the principal cause behind the rotation of dust particles.

  16. AN OBSERVED CORRELATION BETWEEN THERMAL AND NON-THERMAL EMISSION IN GAMMA-RAY BURSTS

    SciTech Connect (OSTI)

    Michael Burgess, J.; Preece, Robert D. [Department of Space Science, University of Alabama in Huntsville, Huntsville, AL 35899 (United States); Ryde, Felix; Axelsson, Magnus [Department of Physics, Royal Institute of Technology (KTH), AlbaNova, SE-106 91 Stockholm (Sweden); Veres, Peter; Mszros, Peter [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Connaughton, Valerie; Briggs, Michael; Bhat, P. N.; Pelassa, Veronique [Center for Space Plasma and Aeronomic Research (CSPAR), University of Alabama in Huntsville, Huntsville, AL 35899 (United States); Pe'er, Asaf [Physics Department, University College Cork, Cork (Ireland); Iyyani, Shabnam [The Oskar Klein Centre for Cosmoparticle Physics, AlbaNova, SE-106 91 Stockholm (Sweden); Goldstein, Adam [Space Science Office, VP62, NASA/Marshall Space Flight Center, Huntsville, AL 35812 (United States); Baring, Matthew G. [Department of Physics and Astronomy, Rice University, MS-108, P.O. Box 1892, Houston, TX 77251 (United States); Byrne, David; Fitzpatrick, Gerard; Foley, Suzanne [University College Dublin, Belfield, Dublin 4 (Ireland); Kocevski, Daniel; Omodei, Nicola [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Paciesas, William S., E-mail: jmichaelburgess@gmail.com, E-mail: rob.preece@nasa.gov, E-mail: felix@particle.kth.se, E-mail: veres@gwu.edu, E-mail: npp@astro.psu.edu [Universities Space Research Association, Huntsville, AL 35805 (United States); and others

    2014-04-01

    Recent observations by the Fermi Gamma-ray Space Telescope have confirmed the existence of thermal and non-thermal components in the prompt photon spectra of some gamma-ray bursts (GRBs). Through an analysis of six bright Fermi GRBs, we have discovered a correlation between the observed photospheric and non-thermal ?-ray emission components of several GRBs using a physical model that has previously been shown to be a good fit to the Fermi data. From the spectral parameters of these fits we find that the characteristic energies, E {sub p} and kT, of these two components are correlated via the relation E {sub p}?T {sup ?} which varies from GRB to GRB. We present an interpretation in which the value of the index ? indicates whether the jet is dominated by kinetic or magnetic energy. To date, this jet composition parameter has been assumed in the modeling of GRB outflows rather than derived from the data.

  17. Direct observation and imaging of a spin-wave soliton with p-like symmetry

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

    Bonetti, S.; Kukreja, R.; Chen, Z.; Macià, F.; Hernàndez, J. M.; Eklund, A.; Backes, D.; Frisch, J.; Katine, J.; Malm, G.; et al

    2015-11-16

    Spin waves, the collective excitations of spins, can emerge as nonlinear solitons at the nanoscale when excited by an electrical current from a nanocontact. These solitons are expected to have essentially cylindrical symmetry (that is, s-like), but no direct experimental observation exists to confirm this picture. Using a high-sensitivity time-resolved magnetic X-ray microscopy with 50 ps temporal resolution and 35 nm spatial resolution, we are able to create a real-space spin-wave movie and observe the emergence of a localized soliton with a nodal line, that is, with p-like symmetry. Moreover, micromagnetic simulations explain the measurements and reveal that the symmetrymore » of the soliton can be controlled by magnetic fields. Our results broaden the understanding of spin-wave dynamics at the nanoscale, with implications for the design of magnetic nanodevices.« less

  18. Amplitude Variability in gamma Dor and delta Sct Stars Observed by Kepler

    SciTech Connect (OSTI)

    Guzik, Joyce Ann; Kosak, Mary Katherine; Bradley, Paul Andrew; Jackiewicz, Jason

    2015-08-17

    The NASA Kepler spacecraft data revealed a large number of new multimode nonradially pulsating gamma Dor and delta Sct variable stars. The Kepler high-precision long time-series photometry makes it possible to study amplitude variations of the frequencies, and recent literature on amplitude and frequency variations in nonradially pulsating variables is summarized. Several methods are applied to study amplitude variability in about a dozen gamma Doradus or delta Scuti candidate variable stars observed for several quarters as part of the Kepler Guest Observer program. The magnitude and timescale of the amplitude variations are discussed, along with the presence or absence of correlations between amplitude variations for different frequencies of a given star. Proposed causes of amplitude spectrum variability that will require further investigation are also discussed.

  19. Observation of the Decay B⁻→Ds(*)+K⁻l⁻ν⁻⁻l

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

    del Amo Sanchez, P.; Lees, J. P.; Poireau, V.; Prencipe, E.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Martinelli, M.; Palano, A.; Pappagallo, M.; et al

    2011-07-22

    We report the observation of the decay B⁻→Ds(*)+K⁻l⁻ν¯l based on 342fb⁻¹ of data collected at the Υ(4S) resonance with the BABAR detector at the PEP-II e⁺e⁻ storage rings at SLAC. A simultaneous fit to three D+s decay chains is performed to extract the signal yield from measurements of the squared missing mass in the B meson decay. We observe the decay B⁻→Ds(*)+K⁻l⁻ν¯l with a significance greater than 5 standard deviations (including systematic uncertainties) and measure its branching fraction to be B(B⁻→Ds(*)+K⁻l⁻ν¯l)=[6.13+1.04-1.03(stat)±0.43(syst)±0.51(B(Ds))]×10⁻⁴, where the last error reflects the limited knowledge of the Ds branching fractions.

  20. Observed galaxy number counts on the lightcone up to second order: II. Derivation

    SciTech Connect (OSTI)

    Bertacca, Daniele; Maartens, Roy; Clarkson, Chris E-mail: roy.maartens@gmail.com

    2014-11-01

    We present a detailed derivation of the observed galaxy number over-density on cosmological scales up to second order in perturbation theory. We include all relativistic effects that arise from observing on the past lightcone. The derivation is in a general gauge, and applies to all dark energy models (including interacting dark energy) and to metric theories of modified gravity. The result will be important for accurate cosmological parameter estimation, including non-Gaussianity, since all projection effects need to be taken into account. It also offers the potential for new probes of General Relativity, dark energy and modified gravity. This paper accompanies Paper I which presents the key results for the concordance model in Poisson gauge.

  1. Observation of the Decay K{sup +} yields P{sup +} v...

    SciTech Connect (OSTI)

    Diwan, M.V.

    1999-05-21

    We have observed 1 event consistent with the signature expected of the rare decay of a positive kaon to a positive pion and a neutrino anti-neutrino pair. In the examined momentum region of 211 to 230 MeV/c in the center of mass of the kaon we estimated the backgrounds to be about 0.08 0.03 events. From this observation we estimate the branching ratio to be 4.2+9.7-3.5 x 10-10. In this presentation I will explain the experiment, and the analysis techniques. I will also discuss the expected improvements in the near future from the analysis of new data sets.

  2. Fermi large area telescope observations of blazar 3C 279 occultations by the sun

    SciTech Connect (OSTI)

    Barbiellini, G.; Bastieri, D.; Buson, S.; Bechtol, K.; Blandford, R. D.; Borgland, A. W.; Buehler, R.; Cameron, R. A.; Chiang, J.; Bellazzini, R.; Bregeon, J.; Bruel, P.; Caraveo, P. A.; Cavazzuti, E.; Ciprini, S.; Cecchi, C.; Chaves, R. C. G.; Cheung, C. C. E-mail: phdmitry@stanford.edu; and others

    2014-04-01

    Observations of occultations of bright ?-ray sources by the Sun may reveal predicted pair halos around blazars and/or new physics, such as, e.g., hypothetical light dark matter particlesaxions. We use Fermi Gamma-Ray Space Telescope (Fermi) data to analyze four occultations of blazar 3C 279 by the Sun on October 8 each year from 2008 to 2011. A combined analysis of the observations of these occultations allows a point-like source at the position of 3C 279 to be detected with significance of ?3?, but does not reveal any significant excess over the flux expected from the quiescent Sun. The likelihood ratio test rules out complete transparency of the Sun to the blazar ?-ray emission at a 3? confidence level.

  3. Simultaneous effect of modified gravity and primordial non-Gaussianity in large scale structure observations

    SciTech Connect (OSTI)

    Mirzatuny, Nareg; Khosravi, Shahram; Baghram, Shant; Moshafi, Hossein E-mail: khosravi@mail.ipm.ir E-mail: hosseinmoshafi@iasbs.ac.ir

    2014-01-01

    In this work we study the simultaneous effect of primordial non-Gaussianity and the modification of the gravity in f(R) framework on large scale structure observations. We show that non-Gaussianity and modified gravity introduce a scale dependent bias and growth rate functions. The deviation from ?CDM in the case of primordial non-Gaussian models is in large scales, while the growth rate deviates from ?CDM in small scales for modified gravity theories. We show that the redshift space distortion can be used to distinguish positive and negative f{sub NL} in standard background, while in f(R) theories they are not easily distinguishable. The galaxy power spectrum is generally enhanced in presence of non-Gaussianity and modified gravity. We also obtain the scale dependence of this enhancement. Finally we define galaxy growth rate and galaxy growth rate bias as new observational parameters to constrain cosmology.

  4. Constraints on decaying dark matter from Fermi observations of nearby galaxies and clusters

    SciTech Connect (OSTI)

    Dugger, Leanna; Profumo, Stefano [Department of Astronomy and Department of Physics, University of California Berkeley, 601 Campbell Hall, Berkeley, CA (United States); Jeltema, Tesla E., E-mail: greentee01@gmail.com, E-mail: tesla@ucolick.org, E-mail: profumo@scipp.ucsc.edu [UCO/Lick Observatories, 1156 High St., Santa Cruz, CA 95064 (United States)

    2010-12-01

    We analyze the impact of Fermi gamma-ray observations (primarily non-detections) of selected nearby galaxies, including dwarf spheroidals, and of clusters of galaxies on decaying dark matter models. We show that the fact that galaxy clusters do not shine in gamma rays puts the most stringent limits available to-date on the lifetime of dark matter particles for a wide range of particle masses and decay final states. In particular, our results put strong constraints on the possibility of ascribing to decaying dark matter both the increasing positron fraction reported by PAMELA and the high-energy feature in the electron-positron spectrum measured by Fermi. Observations of nearby dwarf galaxies and of the Andromeda Galaxy (M31) do not provide as strong limits as those from galaxy clusters, while still improving on previous constraints in some cases.

  5. INTERSTELLAR NEUTRAL ATOMS AT 1 AU OBSERVED BY THE IMAGE/LENA IMAGER

    SciTech Connect (OSTI)

    Fuselier, S. A.; Ghielmetti, A. G.; Wurz, P. E-mail: gmetti@mail.spasci.com

    2009-06-20

    Observations from the Imager for Magnetopause to Aurora: Global Exploration (IMAGE) Low Energy Neutral Atom (LENA) imager from 2005 are used to investigate characteristics of interstellar neutrals in the inner solar system. The LENA imager detected an interstellar neutral signal starting in 2004 December and extending to early 2005 April. Using the orientation of the field of view of the imager and the date of the loss of the interstellar neutral signal, it is concluded that the signal is consistent with a relatively compact (several degrees wide in ecliptic latitude and longitude) source of neutral helium and/or energetic (>150 eV) hydrogen originating from the solar apex direction. Observations later in 2005 are used to distinguish the composition and conclude that the relatively compact source likely contains some energetic hydrogen (in addition to the helium)

  6. Direct observation and imaging of a spin-wave soliton with p-like symmetry

    SciTech Connect (OSTI)

    Bonetti, S.; Kukreja, R.; Chen, Z.; Macià, F.; Hernàndez, J. M.; Eklund, A.; Backes, D.; Frisch, J.; Katine, J.; Malm, G.; Urazhdin, S.; Kent, A. D.; Stöhr, J.; Ohldag, H.; Dürr, H. A.

    2015-11-16

    Spin waves, the collective excitations of spins, can emerge as nonlinear solitons at the nanoscale when excited by an electrical current from a nanocontact. These solitons are expected to have essentially cylindrical symmetry (that is, s-like), but no direct experimental observation exists to confirm this picture. Using a high-sensitivity time-resolved magnetic X-ray microscopy with 50 ps temporal resolution and 35 nm spatial resolution, we are able to create a real-space spin-wave movie and observe the emergence of a localized soliton with a nodal line, that is, with p-like symmetry. Moreover, micromagnetic simulations explain the measurements and reveal that the symmetry of the soliton can be controlled by magnetic fields. Our results broaden the understanding of spin-wave dynamics at the nanoscale, with implications for the design of magnetic nanodevices.

  7. Electron-density comparisons between radar observations and 3-D ionospheric model calculations. Master's thesis

    SciTech Connect (OSTI)

    Johnson, M.W.

    1990-01-01

    A comparison of electron densities calculated from the Utah State University First-Principals Ionospheric Model with simultaneous observations taken at Sondrestrom, Millstone, and Arecibo incoherent-scatter radars was undertaken to better understanding the response of the ionosphere at these longitudinally similar yet latitudinally separated locations. The comparison included over 50 days distributed over 3 1/2 years roughly symmetrical about the last solar-minimum in 1986. The overall trend of the comparison was that to first-order the model reproduces electron densities responding to diurnal, seasonal, geomagnetic, and solar-cycle variations for all three radars. However, some model-observation discrepancies were found. These include, failure of the model to correctly produce an evening peak at Millstone, fall-spring equinox differences at Sondrestrom, tidal structure at Arecibo, and daytime NmF2 values at Arecibo.

  8. DETERMINATION OF NON-THERMAL VELOCITY DISTRIBUTIONS FROM SERTS LINEWIDTH OBSERVATIONS

    SciTech Connect (OSTI)

    Coyner, Aaron J. [Department of Physics, Catholic University of America, 620 Michigan Avenue, Washington, DC 20064 (United States); Davila, Joseph M., E-mail: aaron.j.coyner@nasa.gov [Code 671, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2011-12-01

    Non-thermal velocities obtained from the measurement of coronal Extreme Ultraviolet (EUV) linewidths have been consistently observed in solar EUV spectral observations and have been theorized to result from many plausible scenarios including wave motions, turbulence, or magnetic reconnection. Constraining these velocities can provide a physical limit for the available energy resulting from unresolved motions in the corona. We statistically determine a series of non-thermal velocity distributions from linewidth measurements of 390 emission lines from a wide array of elements and ionization states observed during the Solar Extreme Ultraviolet Research Telescope and Spectrograph 1991-1997 flights covering the spectral range 174-418 A and a temperature range from 80,000 K to 12.6 MK. This sample includes 248 lines from active regions, 101 lines from quiet-Sun regions, and 41 lines were observed from plasma off the solar limb. We find a strongly peaked distribution corresponding to a non-thermal velocity of 19-22 km s{sup -1} in all three of the quiet-Sun, active region, and off-limb distributions. For the possibility of Alfven wave resonance heating, we find that velocities in the core of these distributions do not provide sufficient energy, given typical densities and magnetic field strengths for the coronal plasma, to overcome the estimated coronal energy losses required to maintain the corona at the typical temperatures working as the sole mechanism. We find that at perfect efficiency 50%-60% of the needed energy flux can be produced from the non-thermal velocities measured.

  9. Stratiform and Convective Precipitation Observed by Multiple Radars during the DYNAMO/AMIE Experiment

    SciTech Connect (OSTI)

    Deng, Min; Kollias, Pavlos; Feng, Zhe; Zhang, Chidong; Long, Charles N.; Kalesse, Heike; Chandra, Arunchandra; Kumar, Vickal; Protat, Alain

    2014-11-01

    The motivation for this research is to develop a precipitation classification and rain rate estimation method using cloud radar-only measurements for Atmospheric Radiation Measurement (ARM) long-term cloud observation analysis, which are crucial and unique for studying cloud lifecycle and precipitation features under different weather and climate regimes. Based on simultaneous and collocated observations of the Ka-band ARM zenith radar (KAZR), two precipitation radars (NCAR S-PolKa and Texas A&M University SMART-R), and surface precipitation during the DYNAMO/AMIE field campaign, a new cloud radar-only based precipitation classification and rain rate estimation method has been developed and evaluated. The resulting precipitation classification is equivalent to those collocated SMART-R and S-PolKa observations. Both cloud and precipitation radars detected about 5% precipitation occurrence during this period. The convective (stratiform) precipitation fraction is about 18% (82%). The 2-day collocated disdrometer observations show an increased number concentration of large raindrops in convective rain compared to dominant concentration of small raindrops in stratiform rain. The composite distributions of KAZR reflectivity and Doppler velocity also show two distinct structures for convective and stratiform rain. These indicate that the method produces physically consistent results for two types of rain. The cloud radar-only rainfall estimation is developed based on the gradient of accumulative radar reflectivity below 1 km, near-surface Ze, and collocated surface rainfall (R) measurement. The parameterization is compared with the Z-R exponential relation. The relative difference between estimated and surface measured rainfall rate shows that the two-parameter relation can improve rainfall estimation.

  10. Electron Solvation Dynamics and Reactivity in Ionic Liquids Observed by Picosecond RadiolysisTechniques

    SciTech Connect (OSTI)

    Wishart J. F.; Funston, A.M.; Szreder, T.; Cook, A.R.; Gohdo, M.

    2012-01-01

    On time scales of a nanosecond or less, radiolytically-generated excess electrons in ionic liquids undergo solvation processes and reactions that determine all subsequent chemistry and the accumulation of radiolytic damage. Using picosecond pulse radiolysis detection methods, we observed and quantified the solvation response of the electron in 1-methyl-1-butyl-pyrrolidinium bis(trifluoromethylsulfonyl)amide and used it to understand electron scavenging by a typical solute, duroquinone.

  11. Designing optimal greenhouse gas observing networks that consider performance and cost

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

    Lucas, D. D.; Yver Kwok, C.; Cameron-Smith, P.; Graven, H.; Bergmann, D.; Guilderson, T. P.; Weiss, R.; Keeling, R.

    2014-12-23

    Emission rates of greenhouse gases (GHGs) entering into the atmosphere can be inferred using mathematical inverse approaches that combine observations from a network of stations with forward atmospheric transport models. Some locations for collecting observations are better than others for constraining GHG emissions through the inversion, but the best locations for the inversion may be inaccessible or limited by economic and other non-scientific factors. We present a method to design an optimal GHG observing network in the presence of multiple objectives that may be in conflict with each other. As a demonstration, we use our method to design a prototypemore » network of six stations to monitor summertime emissions in California of the potent GHG 1,1,1,2-tetrafluoroethane (CH2FCF3, HFC-134a). We use a multiobjective genetic algorithm to evolve network configurations that seek to jointly maximize the scientific accuracy of the inferred HFC-134a emissions and minimize the associated costs of making the measurements. The genetic algorithm effectively determines a set of "optimal" observing networks for HFC-134a that satisfy both objectives (i.e., the Pareto frontier). The Pareto frontier is convex, and clearly shows the tradeoffs between performance and cost, and the diminishing returns in trading one for the other. Without difficulty, our method can be extended to design optimal networks to monitor two or more GHGs with different emissions patterns, or to incorporate other objectives and constraints that are important in the practical design of atmospheric monitoring networks.« less

  12. Designing optimal greenhouse gas observing networks that consider performance and cost

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

    Lucas, D. D.; Yver Kwok, C.; Cameron-Smith, P.; Graven, H.; Bergmann, D.; Guilderson, T. P.; Weiss, R.; Keeling, R.

    2015-06-16

    Emission rates of greenhouse gases (GHGs) entering into the atmosphere can be inferred using mathematical inverse approaches that combine observations from a network of stations with forward atmospheric transport models. Some locations for collecting observations are better than others for constraining GHG emissions through the inversion, but the best locations for the inversion may be inaccessible or limited by economic and other non-scientific factors. We present a method to design an optimal GHG observing network in the presence of multiple objectives that may be in conflict with each other. As a demonstration, we use our method to design a prototypemore » network of six stations to monitor summertime emissions in California of the potent GHG 1,1,1,2-tetrafluoroethane (CH2FCF3, HFC-134a). We use a multiobjective genetic algorithm to evolve network configurations that seek to jointly maximize the scientific accuracy of the inferred HFC-134a emissions and minimize the associated costs of making the measurements. The genetic algorithm effectively determines a set of "optimal" observing networks for HFC-134a that satisfy both objectives (i.e., the Pareto frontier). The Pareto frontier is convex, and clearly shows the tradeoffs between performance and cost, and the diminishing returns in trading one for the other. Without difficulty, our method can be extended to design optimal networks to monitor two or more GHGs with different emissions patterns, or to incorporate other objectives and constraints that are important in the practical design of atmospheric monitoring networks.« less

  13. Observation of the tune dependence of the stability threshold current in the PSR (Proton Storage Ring)

    SciTech Connect (OSTI)

    Wang, Tai Sen F.; Colton, E.; Lombardi, A.; Neuffer, D.V.; Thiessen, H.A.

    1989-01-01

    In the high-intensity unbunched-beam experiments carried out in the Proton Storage Ring at Los Alamos National Laboratory, the threshold current of vertical transverse instability showed pronounced differences when the betatron tune varied across an integer. In this paper, we shall present our experimental observations and discuss the possible relations between the threshold current and the machine impedance. The possible effects related to the distorted closed orbit are also discussed. 5 refs., 3 figs., 1 tab.

  14. OBSERVATIONAL STUDY OF THE CONTINUUM AND WATER MASER EMISSION IN THE IRAS 19217+1651 REGION

    SciTech Connect (OSTI)

    Rodriguez-Esnard, T.; Trinidad, M. A.; Migenes, V. E-mail: trinidad@astro.ugto.mx

    2012-12-20

    We report interferometric observations of the high-mass star-forming region IRAS 19217+1651. We observed the radio continuum (1.3 cm and 3.6 cm) and water maser emission using the Very Large Array (VLA-EVLA) in transition mode (configuration A). Two radio continuum sources were detected at both wavelengths, I19217-A and I19217-B. In addition, 17 maser spots were observed distributed mainly in two groups, M1 and M2, and one isolated maser. This latter could be indicating the relative position of another continuum source which we did not detect. The results indicate that I19217-A appears to be consistent with an ultracompact H II region associated with a zero-age main-sequence B0-type star. Furthermore, the 1.3 cm continuum emission of this source suggests a cometary morphology. In addition, I19217-B appears to be an H II region consisting of at least two stars, which may be contributing to its complex structure. It was also found that the H{sub 2}O masers of the group M1 are apparently associated with the continuum source I19217-A. These are tracing motions which are not gravitationally bound according to their spatial distribution and kinematics. They also seem to be describing outflows in the direction of the elongated cometary region. On the other hand, the second maser group, M2, could be tracing the base of a jet. Finally, infrared data from Spitzer, Midcourse Space Experiment, and IRIS show that IRAS 19217+1651 is embedded inside a large open bubble, like a broken ring, which possibly has affected the morphology of the cometary H II region observed at 1.3 cm.

  15. Round Robin Testing of Commercial Hydrogen Sensor Performance - Observations and Results: Preprnt

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

    Round Robin Testing of Commercial Hydrogen Sensor Performance-Observations and Results Preprint W. Buttner, R. Burgess, C. Rivkin, and M. Post National Renewable Energy Laboratory L. Boon-Brett, G. Black, F. Harskamp, and P. Moretto European Commission, DG Joint Research Centre, Institute for Energy Presented at the 2010 National Hydrogen Association Hydrogen Conference and Expo Long Beach, California May 3-6, 2010 Conference Paper NREL/CP-5600-48305 October 2010 NOTICE The submitted manuscript

  16. Putting the Spin on Graphite: Observing the Spins of Impurity Atoms Align |

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

    Stanford Synchrotron Radiation Lightsource Putting the Spin on Graphite: Observing the Spins of Impurity Atoms Align Friday, February 28, 2014 The existence of magnetism in graphite is a very intriguing subject. The possibility to exploit the magnetic properties of a lightweight and robust material based on carbon that can also be produced and manipulated on the nanoscale fascinates scientists and engineers alike. Carbon-based materials can be made e.g. in the form of thin wires (1D), single

  17. Observed Regimes of Mid-Latitude.and Tropical Cirrus Microphysical Behavior

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

    Observed Regimes of Mid-Latitude and Tropical Cirrus Microphysical Behavior A. D. Del Genio and A. B. Wolf National Aeronautics Space Administration Goddard Institute for Space Studies New York, New York G. G. Mace University of Utah Salt Lake City, Utah L. M. Miloshevich National Center for Atmospheric Research Boulder, Colorado Introduction Little is known about the climatological microphysical properties of cirrus clouds. Thus, general circulation model (GCM) cirrus parameterizations often

  18. SWIFT X-RAY OBSERVATIONS OF CLASSICAL NOVAE. II. THE SUPER SOFT SOURCE SAMPLE

    SciTech Connect (OSTI)

    Schwarz, Greg J.; Ness, Jan-Uwe; Osborne, J. P.; Page, K. L.; Evans, P. A.; Beardmore, A. P.; Walter, Frederick M.; Andrew Helton, L.; Woodward, Charles E.; Bode, Mike; Starrfield, Sumner; Drake, Jeremy J.

    2011-12-01

    The Swift gamma-ray burst satellite is an excellent facility for studying novae. Its rapid response time and sensitive X-ray detector provides an unparalleled opportunity to investigate the previously poorly sampled evolution of novae in the X-ray regime. This paper presents Swift observations of 52 Galactic/Magellanic Cloud novae. We included the X-Ray Telescope (0.3-10 keV) instrument count rates and the UltraViolet and Optical Telescope (1700-8000 A) filter photometry. Also included in the analysis are the publicly available pointed observations of 10 additional novae the X-ray archives. This is the largest X-ray sample of Galactic/Magellanic Cloud novae yet assembled and consists of 26 novae with Super Soft X-ray emission, 19 from Swift observations. The data set shows that the faster novae have an early hard X-ray phase that is usually missing in slower novae. The Super Soft X-ray phase occurs earlier and does not last as long in fast novae compared to slower novae. All the Swift novae with sufficient observations show that novae are highly variable with rapid variability and different periodicities. In the majority of cases, nuclear burning ceases less than three years after the outburst begins. Previous relationships, such as the nuclear burning duration versus t{sub 2} or the expansion velocity of the eject and nuclear burning duration versus the orbital period, are shown to be poorly correlated with the full sample indicating that additional factors beyond the white dwarf mass and binary separation play important roles in the evolution of a nova outburst. Finally, we confirm two optical phenomena that are correlated with strong, soft X-ray emission which can be used to further increase the efficiency of X-ray campaigns.

  19. Long-term optical observations of the Be/X-ray binary X Per

    SciTech Connect (OSTI)

    Li, Hui; Yan, Jingzhi; Zhou, Jianeng; Liu, Qingzhong

    2014-12-01

    We present optical spectroscopic observations of X Per from 1999 to 2013 with the 2.16 m telescope at Xinglong Station and the 2.4 m telescope at Lijiang Station, National Astronomical Observatories of China. Combining these observations with the public optical photometric data, we find certain epochs of anti-correlations between the optical brightness and the intensity of the H? and He I 6678 lines, which may be attributed to the mass ejections from the Be star; however, alternative explanations are also possible. The variability of the Fe II 6317 line in the spectra of X Per might also be caused by the shocked waves formed after the mass ejections from the Be star. The X-ray activities of the system might also be connected with the mass ejection events from the Be star. When the ejected materials were transported from the surface of the Be star to the orbit of the neutron star, an X-ray flare could be observed in its X-ray light curves. We use the neutron star as a probe to constrain the motion of the ejected material in the circumstellar disk. With the diffusion time of the ejected material from the surface of the Be star to the orbit of neutron star, the viscosity parameter ? of the circumstellar disk is estimated to be 0.39 and 0.28 for the different times, indicating that the disk around the Be star may be truncated by the neutron star at the 2:1 resonance radius and that a Type I X-ray outburst is unlikely to be observed in X Per.

  20. RHESSI AND TRACE OBSERVATIONS OF MULTIPLE FLARE ACTIVITY IN AR 10656 AND ASSOCIATED FILAMENT ERUPTION

    SciTech Connect (OSTI)

    Joshi, Bhuwan; Kushwaha, Upendra; Cho, K.-S.; Veronig, Astrid M.

    2013-07-01

    We present Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) and Transition Region and Coronal Explorer (TRACE) observations of multiple flare activity that occurred in the NOAA active region 10656 over a period of 2 hr on 2004 August 18. Out of four successive flares, three were class C events, and the final event was a major X1.8 solar eruptive flare. The activities during the pre-eruption phase, i.e., before the X1.8 flare, are characterized by three localized episodes of energy release occurring in the vicinity of a filament that produces intense heating along with non-thermal emission. A few minutes before the eruption, the filament undergoes an activation phase during which it slowly rises with a speed of {approx}12 km s{sup -1}. The filament eruption is accompanied by an X1.8 flare, during which multiple hard X-ray (HXR) bursts are observed up to 100-300 keV energies. We observe a bright and elongated coronal structure simultaneously in E(UV) and 50-100 keV HXR images underneath the expanding filament during the period of HXR bursts, which provides strong evidence for ongoing magnetic reconnection. This phase is accompanied by very high plasma temperatures of {approx}31 MK, followed by the detachment of the prominence from the solar source region. From the location, timing, strength, and spectrum of HXR emission, we conclude that the prominence eruption is driven by the distinct events of magnetic reconnection occurring in the current sheet below the erupting prominence. These multi-wavelength observations also suggest that the localized magnetic reconnections associated with different evolutionary stages of the filament in the pre-eruption phase play an important role in destabilizing the active-region filament through the tether-cutting process, leading to large-scale eruption and X-class flare.

  1. Developing Continuous SCM/CRM Forcing Using NWP Products Constrained by ARM Observations

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

    Developing Continuous SCM/CRM Forcing Using NWP Products Constrained by ARM Observations S. C. Xie, R. T. Cederwall, and J. J. Yio Lawrence Livermore National Laboratory Livermore, California M. H. Zhang State University of New York Stony Brook, New York Introduction This study examines the feasibility of using numerical weather prediction (NWP) model products to replace radiosondes to develop long-term continuous forcing, instead of just intensive operational periods (IOPs), for single-column

  2. Direct Observation of the Oxygenated Species during Oxygen Reduction on a

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

    Platinum Fuel Cell Cathode | Stanford Synchrotron Radiation Lightsource Direct Observation of the Oxygenated Species during Oxygen Reduction on a Platinum Fuel Cell Cathode Friday, December 20, 2013 Fuel Cell Figure 1 Figure 1. In situ x-ray spectroscopy identification and DFT simulations of oxygenated intermediates on a platinum fuel-cell cathode. The study shows that two types of hydroxyl intermediates (non-hydrated OH and hydrated OH) with distinct activities coexist on a fuel-cell

  3. Observation of Ti{sup 4+} ions in a high power impulse magnetron sputtering plasma

    SciTech Connect (OSTI)

    Andersson, Joakim; Anders, Andre; Ehiasarian, Arutiun P.

    2008-08-18

    Multiply charged titanium ions including Ti{sup 4+} were observed in high power impulse magnetron sputtering discharges. Mass/charge spectrometry was used to identify metal ion species. Quadruply charged titanium ions were identified by isotope-induced broadening at mass/charge 12. Due to their high potential energy, Ti{sup 4+} ions give a high yield of secondary electrons, which in turn are likely to be responsible for the generation of multiply charged states.

  4. DOE/SC-ARM-13-014 Biomass Burning Observation Project Science

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

    4 Biomass Burning Observation Project Science Plan LI Kleinman AJ Sedlacek September 2013 DISCLAIMER This report was prepared as an account of work sponsored by the U.S. Government. Neither the United States nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not

  5. Far-ultraviolet observations of comet C/2001 Q4 (NEAT) with FIMS/SPEAR

    SciTech Connect (OSTI)

    Lim, Y.-M.; Min, K.-W.; Feldman, P. D.; Han, W.; Edelstein, J.

    2014-02-01

    We present the results of far-ultraviolet observations of comet C/2001 Q4 (NEAT) that were made with the Far-Ultraviolet Imaging Spectrograph on board the Korean satellite STSAT-1. The observations were conducted in two campaigns during its perihelion approach between 2004 May 8 and 15. Based on the scanning mode observations in the wavelength band of 1400-1700 , we have constructed an image of the comet with an angular size of 55, which corresponds to the central coma region. Several important fluorescence emission lines were detected including S I multiplets at 1429 and 1479 , C I multiplets at 1561 and 1657 , and the CO A{sup 1}?-X{sup 1}?{sup +} Fourth Positive system; we have estimated the production rates of the corresponding species from the fluxes of these emission lines. The estimated production rate of CO was Q {sub CO} = (2.65 0.63) 10{sup 28} s{sup 1}, which is 6.2%-7.4% of the water production rate and is consistent with earlier predictions. The average carbon production rate was estimated to be Q{sub C} = ?1.59 10{sup 28} s{sup 1}, which is ?60% of the CO production rate. However, the observed carbon profile was steeper than that predicted using the two-component Haser model in the inner coma region, while it was consistent with the model in the outer region. The average sulfur production rate was Q{sub S} = (4.031.03) 10{sup 27} s{sup 1}, which corresponds to ?1% of the water production rate.

  6. Van Allen Probes observation and modeling of chorus excitation and propagation during weak geomagnetic activities

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

    He, Yihua; Xiao, Fuliang; Zhou, Qinghua; Yang, Chang; Liu, Si; Baker, D. N.; Kletzing, C. A.; Kurth, W. S.; Hospodarsky, G. B.; Spence, H. E.; et al

    2015-08-20

    We report correlated data on nightside chorus waves and energetic electrons during two small storm periods: 1 November 2012 (Dst ≈ –45) and 14 January 2013 (Dst ≈ –18). The Van Allen Probes simultaneously observed strong chorus waves at locations L = 5.8 – 6.3, with a lower frequency band 0.1–0.5fce and a peak spectral density ~10–4 nT2/Hz. In the same period, the fluxes and anisotropy of energetic (~10–300 keV) electrons were greatly enhanced in the interval of large negative interplanetary magnetic field Bz. Using a bi-Maxwellian distribution to model the observed electron distribution, we perform ray tracing simulations tomore » show that nightside chorus waves are indeed produced by the observed electron distribution with a peak growth for a field-aligned propagation approximately between 0.3fce and 0.4fce, at latitude <7°. Moreover, chorus waves launched with initial normal angles either θ < 90° or > 90° propagate along the field either northward or southward and then bounce back either away from Earth for a lower frequency or toward Earth for higher frequencies. The current results indicate that nightside chorus waves can be excited even during weak geomagnetic activities in cases of continuous injection associated with negative Bz. Furthermore, we examine a dayside event during a small storm C on 8 May 2014 (Dst ≈ –45) and find that the observed anisotropic energetic electron distributions potentially contribute to the generation of dayside chorus waves, but this requires more thorough studies in the future.« less

  7. In situ Observation of Sulfur in Living Mammalian Cells: Uptake of Taurine

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

    into MDCK Cells In situ Observation of Sulfur in Living Mammalian Cells: Uptake of Taurine into MDCK Cells Sulfur is essential for life. It plays important roles in the amino acids methionine and cysteine, and has a structural function in disulfide bonds. As a component of iron-sulfur clusters it takes part in electron and sulfur transfer reactions.1 Glutathione, a sulfur-containing tripeptide, is an important part of biological antioxidant systems.2 Another example for the biological

  8. Microphysical Properties of Single and Mixed-Phase Arctic Clouds Derived from AERI Observations

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

    Microphysical Properties of Single and Mixed-Phase Arctic Clouds Derived from AERI Observations D. D. Turner University of Wisconsin-Madison Madison, Wisconsin and Pacific Northwest National Laboratory Richland, Washington Abstract A novel new approach to retrieve cloud microphysical properties from mixed-phase clouds is presented. This algorithm retrieves cloud optical depth, ice fraction, and the effective size of the water and ice particles from ground-based, high-resolution infrared radiance

  9. NEW X-RAY OBSERVATIONS OF THE GEMINGA PULSAR WIND NEBULA

    SciTech Connect (OSTI)

    Pavlov, George G.; Bhattacharyya, Sudip; Zavlin, Vyacheslav E. E-mail: sudip@tifr.res.i

    2010-05-20

    Previous observations of the middle-aged pulsar Geminga with XMM-Newton and Chandra have shown an unusual pulsar wind nebula (PWN), with a 20'' long central (axial) tail directed opposite to the pulsar's proper motion and two 2' long, bent lateral (outer) tails. Here, we report on a deeper Chandra observation (78 ks exposure) and a few additional XMM-Newton observations of the Geminga PWN. The new Chandra observation has shown that the axial tail, which includes up to three brighter blobs, extends at least 50'' (i.e., 0.06d{sub 250} pc) from the pulsar (d{sub 250} is the distance scaled to 250 pc). It also allowed us to image the patchy outer tails and the emission in the immediate vicinity of the pulsar with high resolution. The PWN luminosity, L{sub 0.3-8{sub keV}} {approx} 3 x 10{sup 29} d {sup 2}{sub 250} erg s{sup -1}, is lower than the pulsar's magnetospheric luminosity by a factor of 10. The spectra of the PWN elements are rather hard (photon index {Gamma} {approx} 1). Comparing the two Chandra images, we found evidence of PWN variability, including possible motion of the blobs along the axial tail. The X-ray PWN is the synchrotron radiation from relativistic particles of the pulsar wind (PW); its morphology is connected with the supersonic motion of Geminga. We speculate that the outer tails are either a sky projection of the limb-brightened boundary of a shell formed in the region of contact discontinuity, where the wind bulk flow is decelerated by shear instability, or polar outflows from the pulsar bent by the ram pressure from the interstellar medium. In the former case, the axial tail may be a jet emanating along the pulsar's spin axis, perhaps aligned with the direction of motion. In the latter case, the axial tail may be the shocked PW collimated by ram pressure.

  10. A way forward in the study of the symmetry energy: experiment, theory, and observation

    SciTech Connect (OSTI)

    Horowitz, Charles; Brown, E F.; Kim, Y.; Lynch, W G.; Michaels, Robert; Ono, A.; Piekarewicz, Jorge; Tsang, M B.; Wolter, H H.

    2014-07-01

    The symmetry energy describes how the energy of nuclear matter rises as one goes away from equal numbers of neutrons and protons. This is very important to describe neutron rich matter in astrophysics. This article reviews our knowledge of the symmetry energy from theoretical calculations, nuclear structure measurements, heavy ion collisions, and astronomical observations. We then present a roadmap to make progress in areas of relevance to the symmetry energy that promotes collaboration between astrophysics and the nuclear physics communities.

  11. Interannual variation of the surface temperature of tropical forests from satellite observations

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

    Gao, Huilin; Zhang, Shuai; Fu, Rong; Li, Wenhong; Dickinson, Robert E.

    2016-01-01

    Land surface temperatures (LSTs) within tropical forests contribute to climate variations. However, observational data are very limited in such regions. This study used passive microwave remote sensing data from the Special Sensor Microwave/Imager (SSM/I) and the Special Sensor Microwave Imager Sounder (SSMIS), providing observations under all weather conditions, to investigate the LST over the Amazon and Congo rainforests. The SSM/I and SSMIS data were collected from 1996 to 2012. The morning and afternoon observations from passive microwave remote sensing facilitate the investigation of the interannual changes of LST anomalies on a diurnal basis. As a result of the variability ofmore » cloud cover and the corresponding reduction of solar radiation, the afternoon LST anomalies tend to vary more than the morning LST anomalies. The dominant spatial and temporal patterns for interseasonal variations of the LST anomalies over the tropical rainforest were analyzed. The impacts of droughts and El Niños on this LST were also investigated. Lastly, the differences between early morning and late afternoon LST anomalies were identified by the remote sensing product, with the morning LST anomalies controlled by humidity (according to comparisons with the National Centers for Environmental Prediction (NCEP) reanalysis data).« less

  12. MODELING SUPER-FAST MAGNETOSONIC WAVES OBSERVED BY SDO IN ACTIVE REGION FUNNELS

    SciTech Connect (OSTI)

    Ofman, L.; Liu, W.; Title, A.; Aschwanden, M.

    2011-10-20

    Recently, quasi-periodic, rapidly propagating waves have been observed in extreme ultraviolet by the Solar Dynamics Observatory/Atmospheric Imaging Assembly (AIA) instrument in about 10 flare/coronal mass ejection (CME) events thus far. A typical example is the 2010 August 1 C3.2 flare/CME event that exhibited arc-shaped wave trains propagating in an active region (AR) magnetic funnel with {approx}5% intensity variations at speeds in the range of 1000-2000 km s{sup -1}. The fast temporal cadence and high sensitivity of AIA enabled the detection of these waves. We identify them as fast magnetosonic waves driven quasi-periodically at the base of the flaring region and develop a three-dimensional MHD model of the event. For the initial state we utilize the dipole magnetic field to model the AR and include gravitationally stratified density at coronal temperature. At the coronal base of the AR, we excite the fast magnetosonic wave by periodic velocity pulsations in the photospheric plane confined to a funnel of magnetic field lines. The excited fast magnetosonic waves have similar amplitude, wavelength, and propagation speeds as the observed wave trains. Based on the simulation results, we discuss the possible excitation mechanism of the waves, their dynamical properties, and the use of the observations for coronal MHD seismology.

  13. LIMITS ON ALPHA PARTICLE TEMPERATURE ANISOTROPY AND DIFFERENTIAL FLOW FROM KINETIC INSTABILITIES: SOLAR WIND OBSERVATIONS

    SciTech Connect (OSTI)

    Bourouaine, Sofiane; Verscharen, Daniel; Chandran, Benjamin D. G.; Maruca, Bennett A.; Kasper, Justin C.

    2013-11-01

    Previous studies have shown that the observed temperature anisotropies of protons and alpha particles in the solar wind are constrained by theoretical thresholds for pressure and anisotropy driven instabilities such as the Alfvn/ion-cyclotron (A/IC) and fast-magnetosonic/whistler (FM/W) instabilities. In this Letter, we use a long period of in situ measurements provided by the Wind spacecraft's Faraday cups to investigate the combined constraint on the alpha proton differential flow velocity and the alpha particle temperature anisotropy due to A/IC and FM/W instabilities. We show that the majority of the data are constrained to lie within the region of parameter space in which A/IC and FM/W waves are either stable or have extremely low growth rates. In the minority of observed cases in which the growth rate of the A/IC (FM/W) instability is comparatively large, we find relatively higher values of T {sub ?}/T {sub p} (T {sub ??}/T {sub ?p}) when the alpha proton differential flow velocity is small, where T {sub ?} and T {sub p} (T {sub ??} and T {sub ?p}) are the perpendicular (parallel) temperatures of alpha particles and protons. We conjecture that this observed feature might arise from preferential alpha particle heating which can drive the alpha particles beyond the instability thresholds.

  14. Sensor Configuration Selection for Discrete-Event Systems under Unreliable Observations

    SciTech Connect (OSTI)

    Wen-Chiao Lin; Tae-Sic Yoo; Humberto E. Garcia

    2010-08-01

    Algorithms for counting the occurrences of special events in the framework of partially-observed discrete event dynamical systems (DEDS) were developed in previous work. Their performances typically become better as the sensors providing the observations become more costly or increase in number. This paper addresses the problem of finding a sensor configuration that achieves an optimal balance between cost and the performance of the special event counting algorithm, while satisfying given observability requirements and constraints. Since this problem is generally computational hard in the framework considered, a sensor optimization algorithm is developed using two greedy heuristics, one myopic and the other based on projected performances of candidate sensors. The two heuristics are sequentially executed in order to find best sensor configurations. The developed algorithm is then applied to a sensor optimization problem for a multiunit- operation system. Results show that improved sensor configurations can be found that may significantly reduce the sensor configuration cost but still yield acceptable performance for counting the occurrences of special events.

  15. Observing the shadow of Einstein-Maxwell-Dilaton-Axion black hole

    SciTech Connect (OSTI)

    Wei, Shao-Wen; Liu, Yu-Xiao E-mail: liuyx@lzu.edu.cn

    2013-11-01

    In this paper, the shadows cast by Einstein-Maxwell-Dilaton-Axion black hole and naked singularity are studied. The shadow of a rotating black hole is found to be a dark zone covered by a deformed circle. For a fixed value of the spin a, the size of the shadow decreases with the dilaton parameter b. The distortion of the shadow monotonically increases with b and takes its maximal when the black hole approaches to the extremal case. Due to the optical properties, the area of the black hole shadow is supposed to equal to the high-energy absorption cross section. Based on this assumption, the energy emission rate is investigated. For a naked singularity, the shadow has a dark arc and a dark spot or straight, and the corresponding observables are obtained. These results show that there is a significant effect of the spin a and dilaton parameter b on these shadows. Moreover, we examine the observables of the shadow cast by the supermassive black hole at the center of the Milky Way, which is very useful for us to probe the nature of the black hole through the astronomical observations in the near future.

  16. In Situ Observation of the Electrochemical Lithiation of a Single SnO2 Nanowire Electrode

    SciTech Connect (OSTI)

    Huang, J. Y.; Zhong, Li; Wang, Chong M.; Sullivan, John P.; Xu, Wu; Zhang, Li Q.; Mao, Scott; Hudak, N.; Liu, Xiao H.; Subramanian, Arun Kumar; Fan, Hongyou; Qi, Liang; Kushima, Akihiro; Li, Ju

    2010-11-18

    We report the first real-time transmission electron microscopy (TEM) observations of the structural evolution and phase transformation of lithium-ion battery anode during the battery charging process. A nanobattery consisting of a single SnO2 nanowire anode and an ionic liquid electrolyte was successfully constructed in a TEM. We observed that during the charging process, the SnO2 crystal was converted to Li2O glass with LixSn nanocrystalline precipitates as the reaction front propagated progressively along the nanowire. After the reaction front passed, the nanowire showed swelling, elongation, and large off-axis distortion (spiraling). Upon completion of the electrochemical charging, the nanowire showed up to 120% elongation and a 30% increase in diameter with a volume expansion of about 272%. The charging front, which separates the reacted and unreacted sections of the nanowire, contains a high density of mobile dislocations, which are continuously nucleated and annihilated at the moving reaction front. This dislocation cloud indicates large in-plane misfit stresses, and serves as structural precursor to the eventual complete solid-state amorphization. The rate of charging in our nanobatteries is found to be proportional to the inverse square root of nanowire length, indicating that a standalone nanobattery or integrated arrays of nanobatteries should have kinetic advantage over conventional battery design. The present observations also provide important mechanistic insights for the design of advanced batteries with improved performance and lifetime for broad electrical energy storage applications.

  17. Dynamical vacuum energy in the expanding Universe confronted with observations: a dedicated study

    SciTech Connect (OSTI)

    Gmez-Valent, Adri; Sol, Joan [High Energy Physics Group, Dept. ECM, and Institut de Cincies del Cosmos, Univ. de Barcelona, Av. Diagonal 647, E-08028 Barcelona, Catalonia (Spain); Basilakos, Spyros, E-mail: adriagova@ecm.ub.edu, E-mail: sola@ecm.ub.edu, E-mail: svasil@academyofathens.gr [Academy of Athens, Research Center for Astronomy and Applied Mathematics, Soranou Efesiou 4, 11527, Athens (Greece)

    2015-01-01

    Despite the many efforts, our theoretical understanding of the ultimate nature of the dark energy component of the universe still lags well behind the astounding experimental evidence achieved from the increasingly sophisticated observational tools at our disposal. While the canonical possibility is a strict cosmological constant, or rigid vacuum energy density ?{sub ?}=const., the exceeding simplicity of this possibility lies also at the root of its unconvincing theoretical status, as there is no explanation for the existence of such constant for the entire cosmic history. Herein we explore general models of the vacuum energy density slowly evolving with the Hubble function H and/or its time derivative, ?{sub ?}=?{sub ?}(H, H-dot ). Some of these models are actually well-motivated from the theoretical point of view and may provide a rich phenomenology that could be explored in future observations, whereas some others have more limitations. In this work, we put them to the test and elucidate which ones are still compatible with the present observations and which ones are already ruled out. We consider their implications on structure formation, in combination with data on type Ia supernovae, the Cosmic Microwave Background, the Baryonic Acoustic Oscillations, and the predicted redshift distribution of cluster-size collapsed structures. The relation of these vacuum models on possible evidence of dynamical dark energy recently pointed out in the literature is also briefly addressed.

  18. Observed Increase of TTL Temperature and Water Vapor in Polluted Couds over Asia

    SciTech Connect (OSTI)

    Su, Hui; Jiang, Jonathan; Liu, Xiaohong; Penner, J.; Read, William G.; Massie, Steven T.; Schoeberl, Mark R.; Colarco, Peter; Livesey, Nathaniel J.; Santee, Michelle L.

    2011-06-01

    Aerosols can affect cloud particle size and lifetime, which impacts precipitation, radiation and climate. Previous studies1-4 suggested that reduced ice cloud particle size and fall speed due to the influence of aerosols may increase evaporation of ice crystals and/or cloud radiative heating in the tropical tropopause layer (TTL), leading to higher water vapor abundance in air entering the stratosphere. Observational substantiation of such processes is still lacking. Here, we analyze new observations from multiple NASA satellites to show the imprint of pollution influence on stratospheric water vapor. We focus our analysis on the highly-polluted South and East Asia region during boreal summer. We find that "polluted" ice clouds have smaller ice effective radius than "clean" clouds. In the TTL, the polluted clouds are associated with warmer temperature and higher specific humidity than the clean clouds. The water vapor difference between the polluted and clean clouds cannot be explained by other meteorological factors, such as updraft and detrainment strength. Therefore, the observed higher water vapor entry value into the stratosphere in the polluted clouds than in the clean clouds is likely a manifestation of aerosol pollution influence on stratospheric water vapor. Given the radiative and chemical importance of stratospheric water vapor, the increasing emission of aerosols over Asia may have profound impacts on stratospheric chemistry and global energy balance and water cycle.

  19. A NEW CHEMICAL EVOLUTION MODEL FOR DWARF SPHEROIDAL GALAXIES BASED ON OBSERVED LONG STAR FORMATION HISTORIES

    SciTech Connect (OSTI)

    Homma, Hidetomo; Murayama, Takashi; Kobayashi, Masakazu A. R.; Taniguchi, Yoshiaki

    2015-02-01

    We present a new chemical evolution model for dwarf spheroidal galaxies (dSphs) in the local universe. Our main aim is to explain both their observed star formation histories and metallicity distribution functions simultaneously. Applying our new model for the four local dSphs, that is, Fornax, Sculptor, LeoII, and Sextans, we find that our new model reproduces the observed chemical properties of the dSphs consistently. Our results show that the dSphs have evolved with both a low star formation efficiency and a large gas outflow efficiency compared with the Milky Way, as suggested by previous works. Comparing the observed [?/Fe]-[Fe/H] relation of the dSphs with the model predictions, we find that our model favors a longer onset time of TypeIa supernovae (i.e., 0.5Gyr) than that suggested in previous studies (i.e., 0.1Gyr). We discuss the origin of this discrepancy in detail.

  20. He II Ly{beta} GUNN-PETERSON ABSORPTION: NEW HST OBSERVATIONS AND THEORETICAL EXPECTATIONS

    SciTech Connect (OSTI)

    Syphers, David; Pieri, Matthew; Shull, J. Michael; Anderson, Scott F.; Zheng, Wei; Kriss, Gerard A.; Smith, Britton; Meiksin, Avery; Schneider, Donald P.; York, Donald G.

    2011-12-01

    Observations of He II Ly{alpha} Gunn-Peterson troughs have proved to be a valuable probe of the epoch of helium reionization at z {approx} 3. Since this optical depth can become unmeasurably large even for modest He II fractions, various alternate techniques have been proposed to push to higher redshift, and among the more promising is looking at higher-order Lyman-series troughs. We here report four new observations of the He II Ly{beta} trough, including new data on the only sightline with a prior Ly{beta} observation. However, the effective optical depth ratio {tau}{sub eff,{beta}}/{tau}{sub eff,{alpha}} is not simply predicted by f{sub {beta}}{lambda}{sub {beta}}/f{sub {alpha}}{lambda}{sub {alpha}} = 0.16, and we analyze cosmological simulations to find that the correct ratio for helium at z {approx} 3 is {approx_equal}0.35. In one case we infer {tau}{sub eff,{alpha}} > 8.8, strong evidence that helium was not fully reionized at z = 3.2-3.5, in agreement with previous measurements suggesting a later completion of reionization.

  1. Qualities of sequential chromospheric brightenings observed in H? and UV images

    SciTech Connect (OSTI)

    Kirk, Michael S.; Balasubramaniam, K. S.; Jackiewicz, Jason; McAteer, R. T. James

    2014-12-01

    Chromospheric flare ribbons observed in H? appear well-organized when first examined: ribbons impulsively brighten, morphologically evolve, and exponentially decay back to pre-flare levels. Upon closer inspection of the H? flares, there is often a significant number of compact areas brightening in concert with the flare eruption but are spatially separated from the evolving flare ribbon. One class of these brightenings is known as sequential chromospheric brightenings (SCBs). SCBs are often observed in the immediate vicinity of erupting flares and are associated with coronal mass ejections. In the past decade there have been several previous investigations of SCBs. These studies have exclusively relied upon H? images to discover and analyze these ephemeral brightenings. This work employs the automated detection algorithm of Kirk et al. to extract the physical qualities of SCBs in observations of ground-based H? images and complementary Atmospheric Imaging Assembly images in He II, C IV, and 1700 . The metadata produced in this tracking process are then culled using complementary Doppler velocities to isolate three distinguishable types of SCBs. From a statistical analysis, we find that the SCBs at the chromospheric H? layer appear earlier and last longer than their corresponding signatures measured in AIA. From this multi-layer analysis, we infer that SCBs are spatially constrained to the mid-chromosphere. We also derive an energy budget to explain SCBs which have a postulated energy of not more than 0.01% of the total flare energy.

  2. Optimized dark matter searches in deep observations of Segue 1 with MAGIC

    SciTech Connect (OSTI)

    Aleksi?, J.; Blanch, O.; Ansoldi, S.; Antonelli, L.A.; Bonnoli, G.; Antoranz, P.; Babic, A.; Bangale, P.; De Almeida, U. Barres; Bock, R.K.; Borracci, F.; Barrio, J.A.; Bonnefoy, S.; Gonzlez, J. Becerra; Berger, K.; Bednarek, W.; Bernardini, E.; Biland, A.; Bretz, T.; Carmona, E. E-mail: jrico@ifae; and others

    2014-02-01

    We present the results of stereoscopic observations of the satellite galaxy Segue 1 with the MAGIC Telescopes, carried out between 2011 and 2013. With almost 160 hours of good-quality data, this is the deepest observational campaign on any dwarf galaxy performed so far in the very high energy range of the electromagnetic spectrum. We search this large data sample for signals of dark matter particles in the mass range between 100 GeV and 20 TeV. For this we use the full likelihood analysis method, which provides optimal sensitivity to characteristic gamma-ray spectral features, like those expected from dark matter annihilation or decay. In particular, we focus our search on gamma-rays produced from different final state Standard Model particles, annihilation with internal bremsstrahlung, monochromatic lines and box-shaped signals. Our results represent the most stringent constraints to the annihilation cross-section or decay lifetime obtained from observations of satellite galaxies, for masses above few hundred GeV. In particular, our strongest limit (95% confidence level) corresponds to a ?500 GeV dark matter particle annihilating into ?{sup +}?{sup ?}, and is of order (?{sub ann}v)? 1.2נ10{sup ?24}cm{sup 3}s{sup ?1} a factor ? 40 above the (?{sub ann}v)? thermal value.

  3. Constraints on the progenitor system and the environs of SN 2014J from deep radio observations

    SciTech Connect (OSTI)

    Prez-Torres, M. A.; Alberdi, A. [Instituto de Astrofsica de Andaluca, Glorieta de las Astronoma, s/n, E-18008 Granada (Spain); Lundqvist, P.; Bjrnsson, C. I.; Fransson, C. [Department of Astronomy, AlbaNova University Center, Stockholm University, SE-10691 Stockholm (Sweden); Beswick, R. J.; Muxlow, T. W. B.; Argo, M. K. [Jodrell Bank Centre for Astrophysics, University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom); Paragi, Z. [Joint Institute for VLBI in Europe, Postbus 2, 7990 AA Dwingeloo (Netherlands); Ryder, S. [Australian Astronomical Observatory, P.O. Box 915, North Ryde, NSW 1670 (Australia); Marcaide, J. M.; Ros, E.; Guirado, J. C. [Departamento de Astronoma i Astrofsica, Universidad de Valencia, E-46100 Burjassot, Valencia (Spain); Mart-Vidal, I. [Onsala Space Observatory, Chalmers University of Technology, SE-43992 Onsala (Sweden)

    2014-09-01

    We report deep EVN and eMERLIN observations of the Type Ia SN 2014J in the nearby galaxy M82. Our observations represent, together with JVLA observations of SNe 2011fe and 2014J, the most sensitive radio studies of Type Ia SNe ever. By combining data and a proper modeling of the radio emission, we constrain the mass-loss rate from the progenitor system of SN 2014J to M-dot ?7.010{sup ?10} M{sub ?} yr{sup ?1} (for a wind speed of 100 km s{sup 1}). If the medium around the supernova is uniform, then n {sub ISM} ? 1.3 cm{sup 3}, which is the most stringent limit for the (uniform) density around a Type Ia SN. Our deep upper limits favor a double-degenerate (DD) scenarioinvolving two WD starsfor the progenitor system of SN 2014J, as such systems have less circumstellar gas than our upper limits. By contrast, most single-degenerate (SD) scenarios, i.e., the wide family of progenitor systems where a red giant, main-sequence, or sub-giant star donates mass to an exploding WD, are ruled out by our observations. (While completing our work, we noticed that a paper by Margutti et al. was submitted to The Astrophysical Journal. From a non-detection of X-ray emission from SN 2014J, the authors obtain limits of M-dot ?1.210{sup ?9} M {sub ?} yr{sup 1} (for a wind speed of 100 km s{sup 1}) and n {sub ISM} ? 3.5 cm{sup 3}, for the ??r {sup 2} wind and constant density cases, respectively. As these limits are less constraining than ours, the findings by Margutti et al. do not alter our conclusions. The X-ray results are, however, important to rule out free-free and synchrotron self-absorption as a reason for the radio non-detections.) Our estimates on the limits on the gas density surrounding SN2011fe, using the flux density limits from Chomiuk et al., agree well with their results. Although we discuss the possibilities of an SD scenario passing observational tests, as well as uncertainties in the modeling of the radio emission, the evidence from SNe 2011fe and 2014J points in the direction of a DD scenario for both.

  4. SWIFT OBSERVATIONS OF MAXI J1659-152: A COMPACT BINARY WITH A BLACK HOLE ACCRETOR

    SciTech Connect (OSTI)

    Kennea, J. A.; Romano, P.; Mangano, V.; Beardmore, A. P.; Evans, P. A.; Curran, P. A.; Markwardt, C. B.; Yamaoka, K.

    2011-07-20

    We report on the detection and follow-up high-cadence monitoring observations of MAXI J1659-152, a bright Galactic X-ray binary transient with a likely black hole accretor, by Swift over a 27 day period after its initial outburst detection. MAXI J1659-152 was discovered almost simultaneously by Swift and the Monitor of All-sky X-ray Image on 2010 September 25, and was monitored intensively from the early stages of the outburst through the rise to a brightness of {approx}0.5 Crab by the Swift X-ray, UV/Optical, and the hard X-ray Burst Alert Telescopes. We present temporal and spectral analysis of the Swift observations. The broadband light curves show variability characteristic of black hole candidate transients. We present the evolution of thermal and non-thermal components of the 0.5-150 keV combined X-ray spectra during the outburst. MAXI J1659-152 displays accretion state changes typically associated with black hole binaries, transitioning from its initial detection in the hard state, to the steep power-law state, followed by a slow evolution toward the thermal state, signified by an increasingly dominant thermal component associated with the accretion disk, although this state change did not complete before Swift observations ended. We observe an anti-correlation between the increasing temperature and decreasing radius of the inner edge of the accretion disk, suggesting that the inner edge of the accretion disk infalls toward the black hole as the disk temperature increases. We observed significant evolution in the absorption column during the initial rise of the outburst, with the absorption almost doubling, suggestive of the presence of an evolving wind from the accretion disk. We detect quasi-periodic oscillations that evolve with the outburst, as well as irregular shaped dips that recur with a period of 2.42 {+-} 0.09 hr, strongly suggesting an orbital period that would make MAXI J1659-152 the shortest period black hole binary yet known.

  5. ALMA observations of the Antennae galaxies. I. A new window on a prototypical merger

    SciTech Connect (OSTI)

    Whitmore, Bradley C.; Brogan, Crystal; Evans, Aaron; Hibbard, John; Leroy, Adam; Remijan, Anthony; Sheth, Kartik; Chandar, Rupali; Johnson, Kelsey; Privon, George

    2014-11-10

    We present the highest spatial resolution (?0.''5) CO (3-2) observations to date of the 'overlap' region in the merging Antennae galaxies (NGC 4038/39), taken with the Atacama Large Millimeter/submillimeter Array. We report on the discovery of a long (3 kpc), thin (aspect ratio 30/1), filament of CO gas that breaks up into roughly 10 individual knots. Each individual knot has a low internal velocity dispersion (?10 km s{sup 1}); the dispersion of the ensemble of knots in the filament is also low (?10 km s{sup 1}). At the other extreme, we find that the individual clouds in the supergiant molecular cloud 2 region discussed by Wilson and collaborators have a large range of internal velocity dispersions (10 to 80 km s{sup 1}), and a large dispersion among the ensemble (?80 km s{sup 1}). Other large-scale features observed in CO emission, and their correspondence with historical counterparts using observations in other wavelengths, are also discussed. We compare the locations of small-scale CO features with a variety of multi-wavelength observations, in particular broad- (BVIJH) and narrow-band data (H{sub ?} and Pa{sub ?}) taken with the Hubble Space Telescope, and radio (3.6 cm) continuum observations taken with the Karl G. Jansky Very Large Array. This comparison leads to the development of an evolutionary classification system that provides a framework for studying the sequence of star cluster formation and evolutionfrom diffuse supergiant molecular clouds (SGMCs) to proto, embedded, emerging, young, intermediate/old clusters. The relative timescales have been assessed by determining the fractional population of sources at each evolutionary stage. The main uncertainty in this estimate is the identification of four regions as candidate protoclusters (i.e., strong compact CO emission but no clearly associated radio emission). Using the evolutionary framework, we estimate that the maximum age range of clusters in a single GMC is ?10 Myr, which suggests that the molecular gas is removed over this timescale, resulting in the cessation of star formation and the destruction of the GMC within a radius of about 200 pc.

  6. ACTIVE REGION MOSS: DOPPLER SHIFTS FROM HINODE/EXTREME-ULTRAVIOLET IMAGING SPECTROMETER OBSERVATIONS

    SciTech Connect (OSTI)

    Tripathi, Durgesh [Inter-University Centre for Astronomy and Astrophysics, Pune University Campus, Pune 411007 (India); Mason, Helen E. [Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom); Klimchuk, James A. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2012-07-01

    Studying the Doppler shifts and the temperature dependence of Doppler shifts in moss regions can help us understand the heating processes in the core of the active regions. In this paper, we have used an active region observation recorded by the Extreme-ultraviolet Imaging Spectrometer (EIS) on board Hinode on 2007 December 12 to measure the Doppler shifts in the moss regions. We have distinguished the moss regions from the rest of the active region by defining a low-density cutoff as derived by Tripathi et al. in 2010. We have carried out a very careful analysis of the EIS wavelength calibration based on the method described by Young et al. in 2012. For spectral lines having maximum sensitivity between log T = 5.85 and log T = 6.25 K, we find that the velocity distribution peaks at around 0 km s{sup -1} with an estimated error of 4-5 km s{sup -1}. The width of the distribution decreases with temperature. The mean of the distribution shows a blueshift which increases with increasing temperature and the distribution also shows asymmetries toward blueshift. Comparing these results with observables predicted from different coronal heating models, we find that these results are consistent with both steady and impulsive heating scenarios. However, the fact that there are a significant number of pixels showing velocity amplitudes that exceed the uncertainty of 5 km s{sup -1} is suggestive of impulsive heating. Clearly, further observational constraints are needed to distinguish between these two heating scenarios.

  7. A VERY DEEP CHANDRA OBSERVATION OF A1795: THE COLD FRONT AND COOLING WAKE

    SciTech Connect (OSTI)

    Ehlert, Steven; McDonald, Michael; Miller, Eric D.; Bautz, Mark W.; David, Laurence P.

    2015-02-01

    We present a new analysis of very deep Chandra observations of the galaxy cluster A1795. Utilizing nearly 750 ks of net ACIS imaging, we are able to resolve the thermodynamic structure of the intracluster medium (ICM) on length scales of ?1 kpc near the cool core. We find several previously unresolved structures, including a high pressure feature to the north of the Brightest Cluster Galaxy (BCG) that appears to arise from the bulk motion of A1795's cool core. To the south of the cool core, we find low temperature (?3 keV), diffuse ICM gas extending for distances of ?50 kpc spatially coincident with previously identified filaments of H? emission. Gas at similar temperatures is also detected in adjacent regions without any H? emission. The X-ray gas coincident with the H? filament has been measured to be cooling spectroscopically at a rate of ?1 M{sub ?} yr{sup ?1}, consistent with measurements of the star formation rate in this region as inferred from ultraviolet (UV) observations, suggesting that the star formation in this filament as inferred by its H? and UV emission can trace its origin to the rapid cooling of dense, X-ray emitting gas. The H? filament is not a unique site of cooler ICM, however, as ICM at similar temperatures and even higher metallicities not cospatial with H? emission is observed just to the west of the H? filament, suggesting that it may have been uplifted by A1795's central active galaxy. Further simulations of cool core sloshing and active galactic nucleus feedback operating in concert with one another will be necessary to understand how such a dynamic cool core region may have originated and why the H? emission is so localized with respect to the cool X-ray gas.

  8. Understanding coronal mass ejections and associated shocks in the solar corona by merging multiwavelength observations

    SciTech Connect (OSTI)

    Zucca, P.; Gallagher, P. T.; Pick, M.; Dmoulin, P.; Kerdraon, A.; Lecacheux, A.

    2014-11-01

    Using multiwavelength imaging observations, in EUV, white light and radio, and radio spectral data over a large frequency range, we analyzed the triggering and development of a complex eruptive event. This one includes two components, an eruptive jet and a coronal mass ejection (CME), which interact during more than 30 minutes, and can be considered as physically linked. This was an unusual event. The jet is generated above a typical complex magnetic configuration that has been investigated in many former studies related to the build-up of eruptive jets; this configuration includes fan-field lines originating from a corona null point above a parasitic polarity, which is embedded in one polarity region of a large active region. The initiation and development of the CME, observed first in EUV, does not show usual signatures. In this case, the eruptive jet is the main actor of this event. The CME appears first as a simple loop system that becomes destabilized by magnetic reconnection between the outer part of the jet and the ambient medium. The progression of the CME is closely associated with the occurrence of two successive type II bursts from a distinct origin. An important part of this study is the first radio type II burst for which the joint spectral and imaging observations were allowed: (1) to follow, step by step, the evolution of the spectrum and of the trajectory of the radio burst, in relationship with the CME evolution and (2) to obtain, without introducing an electronic density model, the B field and the Alfvn speed.

  9. Radio observations reveal a smooth circumstellar environment around the extraordinary type Ib supernova 2012au

    SciTech Connect (OSTI)

    Kamble, Atish; Soderberg, Alicia M.; Margutti, Raffaella; Milisavljevic, Dan; Chakraborti, Sayan; Dittmann, Jason; Drout, Maria; Sanders, Nathan; Chomiuk, Laura; Medvedev, Mikhail; Chevalier, Roger; Chugai, Nikolai; Fransson, Claes; Nakar, Ehud

    2014-12-10

    We present extensive radio and X-ray observations of SN 2012au, an energetic, radio-luminous supernova of Type Ib that exhibits multi-wavelength properties bridging subsets of hydrogen-poor superluminous supernovae, hypernovae, and normal core-collapse supernovae. The observations closely follow models of synchrotron emission from a shock-heated circumburst medium that has a wind density profile (??r {sup 2}). We infer a sub-relativistic velocity for the shock wave v ? 0.2 c and a radius of r ? 1.4 10{sup 16}cm at 25 days after the estimated date of explosion. For a wind velocity of 1000 km s{sup 1}, we determine the mass-loss rate of the progenitor to be M-dot =3.610{sup ?6} M{sub ?} yr{sup ?1}, consistent with the estimates from X-ray observations. We estimate the total internal energy of the radio-emitting material to be E ? 10{sup 47} erg, which is intermediate to SN 1998bw and SN 2002ap. The evolution of the radio light curve of SN 2012au is in agreement with its interaction with a smoothly distributed circumburst medium and the absence of stellar shells ejected from previous outbursts out to r ? 10{sup 17} cm from the supernova site. We conclude that the bright radio emission from SN 2012au was not dissimilar from other core-collapse supernovae despite its extraordinary optical properties, and that the evolution of the SN 2012au progenitor star was relatively quiet, marked with a steady mass loss, during the final years preceding explosion.

  10. Ground-based multiwavelength observations of comet 103P/Hartley 2

    SciTech Connect (OSTI)

    Gicquel, A.; Villanueva, G. L.; Cordiner, M. A.; Milam, S. N.; Charnley, S. B.; Remijan, A. J.; Coulson, I. M.; Chuang, Y.-L.; Kuan, Y.-J. E-mail: stefanie.n.milam@nasa.gov E-mail: steven.b.charnley@nasa.gov E-mail: aremijan@nrao.edu E-mail: ylchuang@std.ntnu.edu.tz

    2014-10-10

    The Jupiter-family comet 103P/Hartley 2 (103P) was the target of the NASA EPOXI mission. In support of this mission, we conducted observations from radio to submillimeter wavelengths of comet 103P in the three weeks preceding the spacecraft rendezvous on UT 2010 November 4.58. This time period included the passage at perihelion and the closest approach of the comet to the Earth. Here, we report detections of HCN, H{sub 2}CO, CS, and OH and upper limits for HNC and DCN toward 103P using the Arizona Radio Observatory Kitt Peak 12 m telescope (ARO 12 m) and submillimeter telescope (SMT), the James Clerk Maxwell Telescope (JCMT), and the Green Bank Telescope (GBT). The water production rate, Q{sub H{sub 2O}} = (0.67-1.07) 10{sup 28} s{sup 1}, was determined from the GBT OH data. From the average abundance ratios of HCN and H{sub 2}CO relative to water (0.13 0.03% and 0.14 0.03%, respectively), we conclude that H{sub 2}CO is depleted and HCN is normal with respect to typically observed cometary mixing ratios. However, the abundance ratio of HCN with water shows a large diversity with time. Using the JCMT data, we measured an upper limit for the DCN/HCN ratio <0.01. Consecutive observations of ortho-H{sub 2}CO and para-H{sub 2}CO on November 2 (from data obtained at the JCMT) allowed us to derive an ortho:para ratio (OPR) of ?2.12 0.59 (1?), corresponding to T {sub spin} > 8 K (2?).

  11. Sparkling extreme-ultraviolet bright dots observed with Hi-C

    SciTech Connect (OSTI)

    Rgnier, S.; Alexander, C. E.; Walsh, R. W.; Winebarger, A. R.; Cirtain, J.; Golub, L.; Korreck, K. E.; Weber, M.; Mitchell, N.; Platt, S.; De Pontieu, B.; Title, A.; Kobayashi, K.; Kuzin, S.; DeForest, C. E.

    2014-04-01

    Observing the Sun at high time and spatial scales is a step toward understanding the finest and fundamental scales of heating events in the solar corona. The high-resolution coronal (Hi-C) instrument has provided the highest spatial and temporal resolution images of the solar corona in the EUV wavelength range to date. Hi-C observed an active region on 2012 July 11 that exhibits several interesting features in the EUV line at 193 . One of them is the existence of short, small brightenings 'sparkling' at the edge of the active region; we call these EUV bright dots (EBDs). Individual EBDs have a characteristic duration of 25 s with a characteristic length of 680 km. These brightenings are not fully resolved by the SDO/AIA instrument at the same wavelength; however, they can be identified with respect to the Hi-C location of the EBDs. In addition, EBDs are seen in other chromospheric/coronal channels of SDO/AIA, which suggests a temperature between 0.5 and 1.5 MK. Based on their frequency in the Hi-C time series, we define four different categories of EBDs: single peak, double peak, long duration, and bursty. Based on a potential field extrapolation from an SDO/HMI magnetogram, the EBDs appear at the footpoints of large-scale, trans-equatorial coronal loops. The Hi-C observations provide the first evidence of small-scale EUV heating events at the base of these coronal loops, which have a free magnetic energy of the order of 10{sup 26} erg.

  12. X-ray observation of the shocked red supergiant wind of Cassiopeia A

    SciTech Connect (OSTI)

    Lee, Jae-Joon; Park, Sangwook; Hughes, John P.; Slane, Patrick O.

    2014-07-01

    Cas A is a Galactic supernova remnant whose supernova explosion is observed to be of Type IIb from spectroscopy of its light echo. Having its SN type known, observational constraints on the mass-loss history of Cas A's progenitor can provide crucial information on the final fate of massive stars. In this paper, we study X-ray characteristics of the shocked ambient gas in Cas A using the 1 Ms observation carried out with the Chandra X-Ray Observatory and try to constrain the mass-loss history of the progenitor star. We identify thermal emission from the shocked ambient gas along the outer boundary of the remnant. Comparison of measured radial variations of spectroscopic parameters of the shocked ambient gas to the self-similar solutions of Chevalier show that Cas A is expanding into a circumstellar wind rather than into a uniform medium. We estimate a wind density n {sub H} ? 0.9 0.3 cm{sup 3} at the current outer radius of the remnant (?3 pc), which we interpret as a dense slow wind from a red supergiant (RSG) star. Our results suggest that the progenitor star of Cas A had an initial mass around 16 M {sub ?}, and its mass before the explosion was about 5 M {sub ?}, with uncertainties of several tens of percent. Furthermore, the results suggest that, among the mass lost from the progenitor star (?11 M {sub ?}), a significant amount (more than 6 M {sub ?}) could have been via its RSG wind.

  13. Observation and modeling of geocoronal charge exchange X-ray emission during solar wind gusts

    SciTech Connect (OSTI)

    Wargelin, B. J.; Kornbleuth, M.; Juda, M.; Martin, P. L.

    2014-11-20

    Solar wind charge exchange (SWCX) X-rays are emitted when highly charged solar wind ions such as O{sup 7{sup +}} collide with neutral gas, including the Earth's tenuous outer atmosphere (exosphere or geocorona) and hydrogen and helium from the local interstellar medium drifting through the heliosphere. This geocoronal and heliospheric emission comprises a significant and varying fraction of the soft X-ray background (SXRB) and is seen in every X-ray observation, with the intensity dependent on solar wind conditions and observation geometry. Under the right conditions, geocoronal emission can increase the apparent SXRB by roughly an order of magnitude for an hour or more. In this work, we study a dozen occasions when the near-Earth solar wind flux was exceptionally high. These gusts of wind lead to abrupt changes in SWCX X-ray emission around Earth, which may or may not be seen by X-ray observatories depending on their line of sight. Using detailed three-dimensional magnetohydrodynamical simulations of the solar wind's interaction with the Earth's magnetosphere, and element abundances and ionization states measured by ACE, we model the time-dependent brightness of major geocoronal SWCX emission lines during those gusts and compare with changes in the X-ray background measured by the Chandra X-ray Observatory. We find reasonably good agreement between model and observation, with measured geocoronal line brightnesses averaged over 1 hr of up to 136 photons s{sup 1} cm{sup 2} sr{sup 1} in the O VII K? triplet around 564 eV.

  14. OPTICAL SPECTRAL OBSERVATIONS OF A FLICKERING WHITE-LIGHT KERNEL IN A C1 SOLAR FLARE

    SciTech Connect (OSTI)

    Kowalski, Adam F.; Cauzzi, Gianna; Fletcher, Lyndsay

    2015-01-10

    We analyze optical spectra of a two-ribbon, long-duration C1.1 flare that occurred on 2011 August 18 within AR 11271 (SOL2011-08-18T15:15). The impulsive phase of the flare was observed with a comprehensive set of space-borne and ground-based instruments, which provide a range of unique diagnostics of the lower flaring atmosphere. Here we report the detection of enhanced continuum emission, observed in low-resolution spectra from 3600 to 4550 acquired with the Horizontal Spectrograph at the Dunn Solar Telescope. A small, ?0.''5 (10{sup 15}cm{sup 2}) penumbral/umbral kernel brightens repeatedly in the optical continuum and chromospheric emission lines, similar to the temporal characteristics of the hard X-ray variation as detected by the Gamma-ray Burst Monitor on the Fermi spacecraft. Radiative-hydrodynamic flare models that employ a nonthermal electron beam energy flux high enough to produce the optical contrast in our flare spectra would predict a large Balmer jump in emission, indicative of hydrogen recombination radiation from the upper flare chromosphere. However, we find no evidence of such a Balmer jump in the bluemost spectral region of the continuum excess. Just redward of the expected Balmer jump, we find evidence of a ''blue continuum bump'' in the excess emission which may be indicative of the merging of the higher order Balmer lines. The large number of observational constraints provides a springboard for modeling the blue/optical emission for this particular flare with radiative-hydrodynamic codes, which are necessary to understand the opacity effects for the continuum and emission line radiation at these wavelengths.

  15. NIR SPECTROSCOPIC OBSERVATION OF MASSIVE GALAXIES IN THE PROTOCLUSTER AT z = 3.09

    SciTech Connect (OSTI)

    Kubo, Mariko; Yamada, Toru; Ichikawa, Takashi; Kajisawa, Masaru; Matsuda, Yuichi; Tanaka, Ichi

    2015-01-20

    We present the results of near-infrared spectroscopic observations of the K-band-selected candidate galaxies in the protocluster at z = 3.09 in the SSA22 field. We observed 67 candidates with K {sub AB} < 24 and confirmed redshifts of the 39 galaxies at 2.0 < z {sub spec} < 3.4. Of the 67 candidates, 24 are certainly protocluster members with 3.04 ? z {sub spec} ? 3.12, which are massive red galaxies that have been unidentified in previous optical observations of the SSA22 protocluster. Many distant red galaxies (J K {sub AB} > 1.4), hyper extremely red objects (J K {sub AB} > 2.1), Spitzer MIPS 24 ?m sources, active galactic nuclei (AGNs) as well as the counterparts of Ly? blobs and the AzTEC/ASTE 1.1 mm sources in the SSA22 field are also found to be protocluster members. The mass of the SSA22 protocluster is estimated to be ?2-5 10{sup 14} M {sub ?}, and this system is plausibly a progenitor of the most massive clusters of galaxies in the current universe. The reddest (J K {sub AB} ? 2.4) protocluster galaxies are massive galaxies with M {sub star} ? 10{sup 11} M {sub ?} showing quiescent star formation activities and plausibly dominated by old stellar populations. Most of these massive quiescent galaxies host moderately luminous AGNs detected by X-ray. There are no significant differences in the [O III] ?5007/H? emission line ratios and [O III] ?5007 line widths and spatial extents of the protocluster galaxies from those of massive galaxies at z ? 2-3 in the general field.

  16. Tonopah Test Range Air Monitoring. CY2014 Meteorological, Radiological, and Airborne Particulate Observations

    SciTech Connect (OSTI)

    Nikoloch, George; Shadel, Craig; Chapman, Jenny; Mizell, Steve A.; McCurdy, Greg; Etyemezian, Vicken; Miller, Julianne J.

    2015-10-01

    In 1963, the U.S. Department of Energy (DOE) (formerly the Atomic Energy Commission [AEC]), implemented Operation Roller Coaster on the Tonopah Test Range (TTR) and an adjacent area of the Nevada Test and Training Range (NTTR) (formerly the Nellis Air Force Range). This test resulted in radionuclide-contaminated soils at Clean Slate I, II, and III. This report documents observations made during ongoing monitoring of radiological, meteorological, and dust conditions at stations installed adjacent to Clean Slate I and Clean Slate III and at the TTR Range Operations Control center. The primary objective of the monitoring effort is to determine if winds blowing across the Clean Slate sites are transporting particles of radionuclide-contaminated soils beyond both the physical and administrative boundaries of the sites. Results for the calendar year (CY) 2014 monitoring are: (1) the gross alpha and gross beta values from the monitoring stations are approximately equivalent to the highest values observed during the CY2014 reporting at the surrounding Community Environmental Monitoring Program (CEMP) stations; (2) only naturally occurring radionuclides were identified in the gamma spectral analyses; (3) the ambient gamma radiation measurements indicate that the average annual gamma exposure is similar at all three monitoring stations and periodic intervals of increased gamma values appear to be associated with storm fronts passing through the area; and (4) the concentrations of both resuspended dust and saltated sand particles generally increase with increasing wind speed. Differences in the observed dust concentrations are likely the result of differences in the soil characteristics immediately adjacent to the monitoring stations. Neither the resuspended particulate radiological analyses nor the ambient gamma radiation measurements suggest wind transport of radionuclide-contaminated soils.

  17. Tonopah Test Range Air Monitoring: CY2013 Meteorological, Radiological, and Airborne Particulate Observations

    SciTech Connect (OSTI)

    Mizell, Steve A; Nikolich, George; Shadel, Craig; McCurdy, Greg; Etyemezian, Vicken; Miller, Julianne J

    2014-10-01

    In 1963, the U.S. Department of Energy (DOE) (formerly the Atomic Energy Commission [AEC]), implemented Operation Roller Coaster on the Tonopah Test Range (TTR) and an adjacent area of the Nevada Test and Training Range (NTTR) (formerly the Nellis Air Force Range). This test resulted in radionuclide-contaminated soils at Clean Slate I, II, and III. This report documents observations made during on-going monitoring of radiological, meteorological, and dust conditions at stations installed adjacent to Clean Slate I and Clean Slate III and at the TTR Range Operations Control center. The primary objective of the monitoring effort is to determine if winds blowing across the Clean Slate sites are transporting particles of radionuclide-contaminated soils beyond both the physical and administrative boundaries of the sites. Results for the calendar year (CY) 2013 monitoring include: (1) the gross alpha and gross beta values from the monitoring stations are approximately equivalent to the highest values observed during the CY2012 reporting at the surrounding Community Environmental Monitoring Program (CEMP) stations (this was the latest documented data available at the time of this writing); (2) only naturally occurring radionuclides were identified in the gamma spectral analyses; (3) the ambient gamma radiation measurements indicate that the average annual gamma exposure is similar at all three monitoring stations and periodic intervals of increased gamma values appear to be associated with storm fronts passing through the area; and (4) the concentrations of both resuspended dust and saltated sand particles generally increase with increasing wind speed. However, differences in the observed dust concentrations are likely due to differences in the soil characteristics immediately adjacent to the monitoring stations. Neither the resuspended particulate radiological analyses nor the ambient gamma radiation measurements suggest wind transport of radionuclide-contaminated soils.

  18. STATISTICAL STUDY OF CHROMOSPHERIC ANEMONE JETS OBSERVED WITH HINODE/SOT

    SciTech Connect (OSTI)

    Nishizuka, N.; Nakamura, T.; Kawate, T.; Singh, K. A. P.; Shibata, K.

    2011-04-10

    The Solar Optical Telescope on board Hinode has revealed numerous tiny jets in all regions of the chromosphere outside of sunspots. A typical chromospheric anemone jet has a cusp-shaped structure and bright footpoint, similar to the shape of an X-ray anemone jet observed previously with the Soft X-ray Telescope on board Yohkoh. The similarity in the shapes of chromospheric and X-ray anemone jets suggests that chromospheric anemone jets are produced as a result of the magnetic reconnection between a small bipole (perhaps a tiny emerging flux) and a pre-existing uniform magnetic field in the lower chromosphere. We examine various chromospheric anemone jets in the solar active region near the solar limb and study the typical features (e.g., length, width, lifetime, and velocity) of the chromospheric anemone jets. Statistical studies show that chromospheric anemone jets have: (1) a typical length {approx}1.0-4.0 Mm, (2) a width {approx}100-400 km, (3) a lifetime {approx}100-500 s, and (4) a velocity {approx}5-20 km s{sup -1}. The velocity of the chromospheric anemone jets is comparable to the local Alfven speed in the lower solar chromosphere ({approx}10 km s{sup -1}). The histograms of chromospheric anemone jets near the limb and near the disk center show similar averages and shapes of distributions, suggesting that the characteristic behavior of chromospheric anemone jets is independent of whether they are observed on the disk or at the limb. The observed relationship between the velocity and length of chromospheric anemone jets shows that the jets do not follow ballistic motion but are more likely accelerated by some other mechanism. This is consistent with numerical simulations of chromospheric anemone jets.

  19. Real-time characterization of partially observed epidemics using surrogate models.

    SciTech Connect (OSTI)

    Safta, Cosmin; Ray, Jaideep; Lefantzi, Sophia; Crary, David; Sargsyan, Khachik; Cheng, Karen

    2011-09-01

    We present a statistical method, predicated on the use of surrogate models, for the 'real-time' characterization of partially observed epidemics. Observations consist of counts of symptomatic patients, diagnosed with the disease, that may be available in the early epoch of an ongoing outbreak. Characterization, in this context, refers to estimation of epidemiological parameters that can be used to provide short-term forecasts of the ongoing epidemic, as well as to provide gross information on the dynamics of the etiologic agent in the affected population e.g., the time-dependent infection rate. The characterization problem is formulated as a Bayesian inverse problem, and epidemiological parameters are estimated as distributions using a Markov chain Monte Carlo (MCMC) method, thus quantifying the uncertainty in the estimates. In some cases, the inverse problem can be computationally expensive, primarily due to the epidemic simulator used inside the inversion algorithm. We present a method, based on replacing the epidemiological model with computationally inexpensive surrogates, that can reduce the computational time to minutes, without a significant loss of accuracy. The surrogates are created by projecting the output of an epidemiological model on a set of polynomial chaos bases; thereafter, computations involving the surrogate model reduce to evaluations of a polynomial. We find that the epidemic characterizations obtained with the surrogate models is very close to that obtained with the original model. We also find that the number of projections required to construct a surrogate model is O(10)-O(10{sup 2}) less than the number of samples required by the MCMC to construct a stationary posterior distribution; thus, depending upon the epidemiological models in question, it may be possible to omit the offline creation and caching of surrogate models, prior to their use in an inverse problem. The technique is demonstrated on synthetic data as well as observations from the 1918 influenza pandemic collected at Camp Custer, Michigan.

  20. ALMA OBSERVATIONS OF THE COLDEST PLACE IN THE UNIVERSE: THE BOOMERANG NEBULA

    SciTech Connect (OSTI)

    Sahai, R.; Vlemmings, W. H. T.; Huggins, P. J.; Nyman, L.-Å.; Gonidakis, I.

    2013-11-10

    The Boomerang Nebula is the coldest known object in the universe, and an extreme member of the class of pre-planetary nebulae, objects which represent a short-lived transitional phase between the asymptotic giant branch and planetary nebula evolutionary stages. Previous single-dish CO (J = 1-0) observations (with a 45'' beam) showed that the high-speed outflow in this object has cooled to a temperature significantly below the temperature of the cosmic background radiation. Here we report the first observations of the Boomerang Nebula with ALMA in the CO J = 2-1 and J = 1-0 lines to resolve the structure of this ultra-cold nebula. We find a central hourglass-shaped nebula surrounded by a patchy, but roughly round, cold high-velocity outflow. We compare the ALMA data with visible-light images obtained with the Hubble Space Telescope and confirm that the limb-brightened bipolar lobes seen in these data represent hollow cavities with dense walls of molecular gas and dust producing both the molecular-emission-line and scattered-light structures seen at millimeter and visible wavelengths. The large diffuse biconical shape of the nebula seen in the visible wavelength range is likely due to preferential illumination of the cold, high-velocity outflow. We find a compact source of millimeter-wave continuum in the nebular waist—these data, together with sensitive upper limits on the radio continuum using observations with ATCA, indicate the presence of a substantial mass of very large (millimeter-sized) grains in the waist of the nebula. Another unanticipated result is the detection of CO emission regions beyond the ultra-cold region which indicate the re-warming of the cold gas, most likely due to photoelectric grain heating.

  1. Herschel HIFI observations of O{sub 2} toward Orion: special conditions for shock enhanced emission

    SciTech Connect (OSTI)

    Chen, Jo-Hsin; Goldsmith, Paul F.; Viti, Serena; Snell, Ronald; Lis, Dariusz C.; Benz, Arnold; Bergin, Edwin; Black, John; Hjalmarson, ke; Caselli, Paola; Encrenaz, Pierre; Falgarone, Edith; Hollenbach, David; Kaufman, Michael; Melnick, Gary; Neufeld, David; Pagani, Laurent; and others

    2014-10-01

    We report observations of molecular oxygen (O{sub 2}) rotational transitions at 487 GHz, 774 GHz, and 1121 GHz toward Orion Peak A. The O{sub 2} lines at 487 GHz and 774 GHz are detected at velocities of 10-12 km s{sup 1} with line widths ?3 km s{sup 1}; however, the transition at 1121 GHz is not detected. The observed line characteristics, combined with the results of earlier observations, suggest that the region responsible for the O{sub 2} emission is ?9'' (6 10{sup 16} cm) in size, and is located close to the H {sub 2} Peak 1 position (where vibrationally excited H{sub 2} emission peaks), and not at Peak A, 23'' away. The peak O{sub 2} column density is ?1.1 10{sup 18} cm{sup 2}. The line velocity is close to that of the 621 GHz water maser emission found in this portion of the Orion Molecular Cloud, and having a shock with velocity vector lying nearly in the plane of the sky is consistent with producing maximum maser gain along the line of sight. The enhanced O{sub 2} abundance compared to that generally found in dense interstellar clouds can be explained by passage of a low-velocity C shock through a clump with preshock density 2 10{sup 4} cm{sup 3}, if a reasonable flux of UV radiation is present. The postshock O{sub 2} can explain the emission from the source if its line-of-sight dimension is ?10 times larger than its size on the plane of the sky. The special geometry and conditions required may explain why O{sub 2} emission has not been detected in the cores of other massive star-forming molecular clouds.

  2. Scanning Cloud Radar Observations at Azores: Preliminary 3D Cloud Products

    SciTech Connect (OSTI)

    Kollias, P.; Johnson, K.; Jo, I.; Tatarevic, A.; Giangrande, S.; Widener, K.; Bharadwaj, N.; Mead, J.

    2010-03-15

    The deployment of the Scanning W-Band ARM Cloud Radar (SWACR) during the AMF campaign at Azores signals the first deployment of an ARM Facility-owned scanning cloud radar and offers a prelude for the type of 3D cloud observations that ARM will have the capability to provide at all the ARM Climate Research Facility sites by the end of 2010. The primary objective of the deployment of Scanning ARM Cloud Radars (SACRs) at the ARM Facility sites is to map continuously (operationally) the 3D structure of clouds and shallow precipitation and to provide 3D microphysical and dynamical retrievals for cloud life cycle and cloud-scale process studies. This is a challenging task, never attempted before, and requires significant research and development efforts in order to understand the radar's capabilities and limitations. At the same time, we need to look beyond the radar meteorology aspects of the challenge and ensure that the hardware and software capabilities of the new systems are utilized for the development of 3D data products that address the scientific needs of the new Atmospheric System Research (ASR) program. The SWACR observations at Azores provide a first look at such observations and the challenges associated with their analysis and interpretation. The set of scan strategies applied during the SWACR deployment and their merit is discussed. The scan strategies were adjusted for the detection of marine stratocumulus and shallow cumulus that were frequently observed at the Azores deployment. Quality control procedures for the radar reflectivity and Doppler products are presented. Finally, preliminary 3D-Active Remote Sensing of Cloud Locations (3D-ARSCL) products on a regular grid will be presented, and the challenges associated with their development discussed. In addition to data from the Azores deployment, limited data from the follow-up deployment of the SWACR at the ARM SGP site will be presented. This effort provides a blueprint for the effort required for the development of 3D cloud products from all new SACRs that the program will deploy at all fixed and mobile sites by the end of 2010.

  3. Observation of narrow structures in the p-p analyzing power around 1 GeV

    SciTech Connect (OSTI)

    Hajime, Shimizu . Dept. of Physics)

    1989-01-01

    The momentum dependence of the analyzing power Ay in proton-proton elastic scattering has been measured in small steps using an internal target inserted into a polarized proton beam during acceleration from 1 to 3 GeV/c. The momentum bin size ranges from 5 to 18 MeV/c. The relative uncertainty of the analyzing power, {Delta}Ay, is typically less than 0.01 for each momentum bin. Narrow structures have been observed in the two-proton invariant mass distribution of the analyzing power. 15 refs., 5 figs., 1 tab.

  4. Observation of spectral evolution during the formation of a Ni2 kondo molecule

    SciTech Connect (OSTI)

    Madhavan, V.; Jamneala, T.; Nagaoka, K.; Chen, W.; Li, Je-Luen; Louie, Steven G.; Crommie, M.F.

    2002-04-15

    We have used atomic manipulation and scanning tunneling spectroscopy to study the evolution in electronic properties that occurs as two Ni atoms are merged into a single magnetic molecule on Au(111). We observe energetic shifting of molecular d-orbitals and a strong decrease in the molecular Kondo temperature as Ni-Ni separation is reduced to 3.4+ or -0.3Angstroms. These results are qualitatively explained by a combination of spin-1/2-s-d model and density-functional calculations.

  5. Observation of large magnetocaloric effect in HoRu{sub 2}Si{sub 2}

    SciTech Connect (OSTI)

    Paramanik, Tapas Das, Kalipada; Das, I.

    2014-02-28

    Detailed magnetic, magnetotransport, and magnetocaloric measurements on HoRu{sub 2}Si{sub 2} have been performed. In this Letter, we report presence of spin reorientation transition below paramagnetic to antiferromagnetic transition temperature (T{sub N} = 19 K). Large magnetic entropy change 9.1 J/kg K and large negative magnetoresistance ∼21% in a magnetic field of 5 T has been observed around T{sub N}, which is associated with field induced spin-flip metamagnetic transition.

  6. First observation of magnetic moment precession of channeled particles in bent crystals

    SciTech Connect (OSTI)

    Chen, D.; Albuquerque, I.F.; Baublis, V.V.; Bondar, N.F.; Carrigan, R.A. Jr.; Cooper, P.S.; Lisheng, D.; Denisov, A.S.; Dobrovolsky, A.V.; Dubbs, T.; Endler, A.M.F.; Escobar, C.O.; Foucher, M.; Golovtsov, V.L.; Goritchev, P.A.; Gottschalk, H.; Gouffon, P.; Grachev, V.T.; Khanzadeev, A.V.; Kubantsev, M.A.; Kuropatkin, N.P.; Lach, J.; Lang Pengfei; Lebedenko, V.N.; Li Chengze; Li Yunshan; Mahon, J.R.P.; McCliment, E.; Morelos, A.; Newsom, C.; Pommot Maia, M.C.; Samsonov, V.M.; Schegelsky, V.A.; Shi Huanzhang; Smith, V.J.; Sun, C.R.; Tang Fukun; Terentyev, N.K.; Timm, S.; Tkatch, I.I.; Uvarov, L.N.; Vorobyov, A.A.; Yan Jie; Zhao Wenheng; Zheng Shuchen; Zhong Yuanyuan Institute of High Energy Physics, Beijing H. H. Wills Physics Laboratory, University of Bristol Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 Fermi National Accelerator Laboratory, Batavia, Illinois 60510

    1992-12-07

    Spin precession of channeled particles in bent crystals has been observed for the first time. Polarized [Sigma][sup +] were channeled using bent Si crystals. These crystals provided an effective magnetic field of 45 T which resulted in a measured spin precession of 60[plus minus]17[degree]. This agrees with the prediction of 62[plus minus]2[degree] using the world average of [Sigma][sup +] magnetic moment measurements. This new technique gives a [Sigma][sup +] magnetic moment of (2.40[plus minus]0.46[plus minus]0.40)[mu][sub [ital N

  7. Time Resolved Collapse of a Folding Protein Observed with Small Angle X-Ray Scattering

    SciTech Connect (OSTI)

    Pollack, L.; Tate, M. W.; Finnefrock, A. C.; Kalidas, C.; Trotter, S.; Darnton, N. C.; Lurio, L.; Austin, R. H.; Batt, C. A.; Gruner, S. M. (and others)

    2001-05-21

    High-intensity, ''pink'' beam from an undulator was used in conjunction with microfabricated rapid-fluid mixing devices to monitor the early events in protein folding with time resolved small angle x-ray scattering. This Letter describes recent work on the protein bovine {beta} -lactoglobulin where collapse from an expanded to a compact set of states was directly observed on the millisecond time scale. The role of chain collapse, one of the initial stages of protein folding, is not currently understood. The characterization of transient, compact states is vital in assessing the validity of theories and models of the folding process.

  8. Observed 20th Century Desert Dust Variability: Impact on Climate and Biogeochemistry

    SciTech Connect (OSTI)

    Mahowald, Natalie; Kloster, Silvia; Engelstaedter, S.; Moore, Jefferson Keith; Mukhopadhyay, S.; McConnell, J. R.; Albani, S.; Doney, Scott C.; Bhattacharya, A.; Curran, M. A. J.; Flanner, Mark G.; Hoffman, Forrest M; Lawrence, David M.; Lindsay, Keith; Mayewski, P. A.; Neff, Jason; Rothenberg, D.; Thomas, E.; Thornton, Peter E; Zender, Charlie S.

    2010-01-01

    Desert dust perturbs climate by directly and indirectly interacting with incoming solar and outgoing long wave radiation, thereby changing precipitation and temperature, in addition to modifying ocean and land biogeochemistry. While we know that desert dust is sensitive to perturbations in climate and human land use, previous studies have been unable to determine whether humans were increasing or decreasing desert dust in the global average. Here we present observational estimates of desert dust based on paleodata proxies showing a doubling of desert dust during the 20th century over much, but not all the globe. Large uncertainties remain in estimates of desert dust variability over 20th century due to limited data. Using these observational estimates of desert dust change in combination with ocean, atmosphere and land models, we calculate the net radiative effect of these observed changes (top of atmosphere) over the 20th century to be -0.14 {+-} 0.11 W/m{sup 2} (1990-1999 vs. 1905-1914). The estimated radiative change due to dust is especially strong between the heavily loaded 1980-1989 and the less heavily loaded 1955-1964 time periods (-0.57 {+-} 0.46 W/m{sup 2}), which model simulations suggest may have reduced the rate of temperature increase between these time periods by 0.11 C. Model simulations also indicate strong regional shifts in precipitation and temperature from desert dust changes, causing 6 ppm (12 PgC) reduction in model carbon uptake by the terrestrial biosphere over the 20th century. Desert dust carries iron, an important micronutrient for ocean biogeochemistry that can modulate ocean carbon storage; here we show that dust deposition trends increase ocean productivity by an estimated 6% over the 20th century, drawing down an additional 4 ppm (8 PgC) of carbon dioxide into the oceans. Thus, perturbations to desert dust over the 20th century inferred from observations are potentially important for climate and biogeochemistry, and our understanding of these changes and their impacts should continue to be refined.

  9. Observation of a new charged charmoniumlike state inB0?J/?K-?+decays

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

    Chilikin, K.; Mizuk, R.; Adachi, I.; Aihara, H.; Al Said, S.; Arinstein, K.; Asner, D.?M.; Aulchenko, V.; Aushev, T.; Ayad, R.; et al

    2014-12-16

    We present the results of an amplitude analysis of B0?J/?K-?+ decays. A new charged charmoniumlike state Zc(4200)+ decaying to J/??+ is observed with a significance of 6.2?. The mass and width of the Zc(4200)+ are 4196+31-29+17-13 MeV/c2 and 370+70-70+70-132 MeV, respectively; the preferred assignment of the quantum numbers is JP=1+. In addition, we find evidence for Zc(4430)+?J/??+. The analysis is based on a 711 fb-1 data sample collected by the Belle detector at the asymmetric-energy e+e- collider KEKB.

  10. In operandi observation of dynamic annealing: A case study of boron in germanium nanowire devices

    SciTech Connect (OSTI)

    Kole?nik-Gray, Maria M.; Krsti?, Vojislav; Sorger, Christian; Weber, Heiko B.; Biswas, Subhajit; Holmes, Justin D.

    2015-06-08

    We report on the implantation of boron in individual, electrically contacted germanium nanowires with varying diameter and present a technique that monitors the electrical properties of a single device during implantation of ions. This method gives improved access to study the dynamic annealing ability of the nanowire at room temperature promoted by its quasi-one-dimensional confinement. Based on electrical data, we find that the dopant activation efficiency is nontrivially diameter dependent. As the diameter decreases, a transition from a pronounced dynamic-annealing to a radiation-damage dominated regime is observed.

  11. DE/SC-ARM/TR-130 Aerosol Observing System Cloud Condensation Nuclei Average

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

    DE/SC-ARM/TR-130 Aerosol Observing System Cloud Condensation Nuclei Average (AOSCCNAVG) Value-Added Product Y Shi A Jefferson C Flynn July 2013 DOE/SC-ARM/TR-130 DISCLAIMER This report was prepared as an account of work sponsored by the U.S. Government. Neither the United States nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus,

  12. Four-Dimensional Data Assimilation Boundary-Layer Observations Over the Southern

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

    Boundary-Layer Observations Over the Southern Great Plains Cloud and Radiation Testbed Site During the November Flux-Profiler Test s. P. Oncley and J. Van Baelen National Center for Atmospheric Research(8) Boulder, CO 80307-3000 Introduction Resu Its Figure 1 shows the raw data from two of the ten profile patterns flown during this experiment. Each aircraft profile consisted of a descent to the profiler site followed by 3-5 legs at increasing heights. Note that because of this flightpattern, the

  13. Strangeness suppression of qq¯ creation observed in exclusive reactions

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

    Mestayer, M. D.; Park, K.; Adhikari, K. P.; Aghasyan, M.; Pereira, S. Anefalos; Ball, J.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Biselli, A. S.; et al

    2014-10-10

    In this study, we measured the ratios of electroproduction cross sections from a proton target for three exclusive meson-baryon final states: ΛK+, pπ0, and nπ+, with the CLAS detector at Jefferson Lab. Using a simple model of quark hadronization, we extract qq¯ creation probabilities for the first time in exclusive two-body production, in which only a single qq¯ pair is created. We observe a sizable suppression of strange quark-antiquark pairs compared to nonstrange pairs, similar to that seen in high-energy production.

  14. HIPPO (HIAPER Pole-to-Pole Observations) Data from CDIAC's HIPPO Data Archive

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

    The HIPPO (HIAPER Pole-to-Pole Observations) study of the carbon cycle and greenhouse gases measured meteorology, atmospheric chemistry, and aerosol constituents along transects from approximately pole-to-pole over the Pacific Ocean. HIPPO flew hundreds of vertical profiles from the ocean/ice surface to as high as the tropopause, at five times during different seasons over a three year period from 2009-2011. HIPPO provides the first high-resolution vertically-resolved global survey of a comprehensive suite of atmospheric trace gases and aerosols pertinent to understanding the carbon cycle and challenging global climate models.

  15. Observed galaxy number counts on the lightcone up to second order: I. Main result

    SciTech Connect (OSTI)

    Bertacca, Daniele; Maartens, Roy; Clarkson, Chris E-mail: roy.maartens@gmail.com

    2014-09-01

    We present the galaxy number overdensity up to second order in redshift space on cosmological scales for a concordance model. The result contains all general relativistic effects up to second order that arise from observing on the past light cone, including all redshift effects, lensing distortions from convergence and shear, and contributions from velocities, Sachs-Wolfe, integrated SW and time-delay terms. This result will be important for accurate calculation of the bias on estimates of non-Gaussianity and on precision parameter estimates, introduced by nonlinear projection effects.

  16. Coherent beam-beam effects observation and mitigation at the RHIC collider

    SciTech Connect (OSTI)

    White S.; Fischer, W.; Luo, Y.

    2012-05-20

    In polarized proton operation in RHIC coherent beam-beam modes are routinely observed with beam transfer function measurements in the vertical plane. With the existence of coherent modes a larger space is required in the tune diagram than without them and stable conditions can be compromised for operation with high intensity beams as foreseen for future luminosity upgrades. We report on experiments and simulations carried out to understand the existence of coherent modes in the vertical plane and their absence in the horizontal plane, and investigate possible mitigation strategies.

  17. Alma observations of nearby luminous infrared galaxies with various agn energetic contributions using dense gas tracers

    SciTech Connect (OSTI)

    Imanishi, Masatoshi; Nakanishi, Kouichiro

    2014-07-01

    We present the results of our ALMA Cycle 0 observations, using HCN/HCO{sup +}/HNC J = 4-3 lines, of six nearby luminous infrared galaxies with various energetic contributions from active galactic nuclei (AGNs) estimated from previous infrared spectroscopy. These lines are very effective for probing the physical properties of high-density molecular gas around the hidden energy sources in the nuclear regions of these galaxies. We find that HCN to HCO{sup +} J = 4-3 flux ratios tend to be higher in AGN-important galaxies than in starburst-dominated regions, as was seen at the J = 1-0 transition, while there is no clear difference in the HCN-to-HNC J = 4-3 flux ratios among observed sources. A galaxy with a starburst-type infrared spectral shape and very large molecular line widths shows a high HCN-to-HCO{sup +} J = 4-3 flux ratio, which could be due to turbulence-induced heating. We propose that enhanced HCN J = 4-3 emission relative to HCO{sup +} J = 4-3 could be used to detect more energetic activity than normal starbursts, including deeply buried AGNs, in dusty galaxy populations.

  18. ATMOSPHERIC IMAGING ASSEMBLY OBSERVATIONS OF CORONAL LOOPS: CROSS-FIELD TEMPERATURE DISTRIBUTIONS

    SciTech Connect (OSTI)

    Schmelz, J. T.; Jenkins, B. S.; Pathak, S., E-mail: jschmelz@memphis.edu [Physics Department, University of Memphis, Memphis, TN 38152 (United States)

    2013-06-10

    We construct revised response functions for the Atmospheric Imaging Assembly (AIA) using the new atomic data, ionization equilibria, and coronal abundances available in CHIANTI 7.1. We then use these response functions in multithermal analysis of coronal loops, which allows us to determine a specific cross-field temperature distribution without ad hoc assumptions. Our method uses data from the six coronal filters and the Monte Carlo solutions available from our differential emission measure (DEM) analysis. The resulting temperature distributions are not consistent with isothermal plasma. Therefore, the observed loops cannot be modeled as single flux tubes and must be composed of a collection of magnetic strands. This result is now supported by observations from the High-resolution Coronal Imager, which show fine-scale braiding of coronal strands that are reconnecting and releasing energy. Multithermal analysis is one of the major scientific goals of AIA, and these results represent an important step toward the successful achievement of that goal. As AIA DEM analysis becomes more straightforward, the solar community will be able to take full advantage of the state-of-the-art spatial, temporal, and temperature resolution of the instrument.

  19. Radiative observables for linearized gravity on asymptotically flat spacetimes and their boundary induced states

    SciTech Connect (OSTI)

    Benini, Marco Dappiaggi, Claudio; Murro, Simone

    2014-08-01

    We discuss the quantization of linearized gravity on globally hyperbolic, asymptotically flat, vacuum spacetimes, and the construction of distinguished states which are both of Hadamard form and invariant under the action of all bulk isometries. The procedure, we follow, consists of looking for a realization of the observables of the theory as a sub-algebra of an auxiliary, non-dynamical algebra constructed on future null infinity ??. The applicability of this scheme is tantamount to proving that a solution of the equations of motion for linearized gravity can be extended smoothly to ??. This has been claimed to be possible provided that a suitable gauge fixing condition, first written by Geroch and Xanthopoulos [Asymptotic simplicity is stable, J. Math. Phys. 19, 714 (1978)], is imposed. We review its definition critically, showing that there exists a previously unnoticed obstruction in its implementation leading us to introducing the concept of radiative observables. These constitute an algebra for which a Hadamard state induced from null infinity and invariant under the action of all spacetime isometries exists and it is explicitly constructed.

  20. Observation of excited state charge transfer with fs/ps-CARS

    SciTech Connect (OSTI)

    Blom, Alex Jason

    2009-08-01

    Excited state charge transfer processes are studied using the fs/ps-CARS probe technique. This probe allows for multiplexed detection of Raman active vibrational modes. Systems studied include Michler's Ketone, Coumarin 120, 4-dimethylamino-4{prime}-nitrostilbene, and several others. The vibrational spectrum of the para di-substituted benzophenone Michler's Ketone in the first excited singlet state is studied for the first time. It is found that there are several vibrational modes indicative of structural changes of the excited molecule. A combined experimental and theoretical approach is used to study the simplest 7-amino-4-methylcoumarin, Coumarin 120. Vibrations observed in FTIR and spontaneous Raman spectra are assigned using density functional calculations and a continuum solvation model is used to predict how observed modes are affected upon inclusion of a solvent. The low frequency modes of the excited state charge transfer species 4-dimethylamino-4{prime}-nitrostilbene are studied in acetonitrile. Results are compared to previous work on this molecule in the fingerprint region. Finally, several partially completed projects and their implications are discussed. These include the two photon absorption of Coumarin 120, nanoconfinement in cyclodextrin cavities and sensitization of titania nanoparticles.