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Sample records for billion electron volts

  1. Feasibility study for mega-electron-volt electron beam tomography

    SciTech Connect

    Hampel, U.; Baertling, Y.; Hoppe, D.; Kuksanov, N.; Fadeev, S.; Salimov, R.

    2012-09-15

    Electron beam tomography is a promising imaging modality for the study of fast technical processes. But for many technical objects of interest x rays of several hundreds of keV energy are required to achieve sufficient material penetration. In this article we report on a feasibility study for fast electron beam computed tomography with a 1 MeV electron beam. The experimental setup comprises an electrostatic accelerator with beam optics, transmission target, and a single x-ray detector. We employed an inverse fan-beam tomography approach with radiographic projections being generated from the linearly moving x-ray source. Angular projections were obtained by rotating the object.

  2. Feasibility study for mega-electron-volt electron beam tomography.

    PubMed

    Hampel, U; Bärtling, Y; Hoppe, D; Kuksanov, N; Fadeev, S; Salimov, R

    2012-09-01

    Electron beam tomography is a promising imaging modality for the study of fast technical processes. But for many technical objects of interest x rays of several hundreds of keV energy are required to achieve sufficient material penetration. In this article we report on a feasibility study for fast electron beam computed tomography with a 1 MeV electron beam. The experimental setup comprises an electrostatic accelerator with beam optics, transmission target, and a single x-ray detector. We employed an inverse fan-beam tomography approach with radiographic projections being generated from the linearly moving x-ray source. Angular projections were obtained by rotating the object.

  3. Mega-electron-volt ultrafast electron diffraction at SLAC National Accelerator Laboratory.

    PubMed

    Weathersby, S P; Brown, G; Centurion, M; Chase, T F; Coffee, R; Corbett, J; Eichner, J P; Frisch, J C; Fry, A R; Gühr, M; Hartmann, N; Hast, C; Hettel, R; Jobe, R K; Jongewaard, E N; Lewandowski, J R; Li, R K; Lindenberg, A M; Makasyuk, I; May, J E; McCormick, D; Nguyen, M N; Reid, A H; Shen, X; Sokolowski-Tinten, K; Vecchione, T; Vetter, S L; Wu, J; Yang, J; Dürr, H A; Wang, X J

    2015-07-01

    Ultrafast electron probes are powerful tools, complementary to x-ray free-electron lasers, used to study structural dynamics in material, chemical, and biological sciences. High brightness, relativistic electron beams with femtosecond pulse duration can resolve details of the dynamic processes on atomic time and length scales. SLAC National Accelerator Laboratory recently launched the Ultrafast Electron Diffraction (UED) and microscopy Initiative aiming at developing the next generation ultrafast electron scattering instruments. As the first stage of the Initiative, a mega-electron-volt (MeV) UED system has been constructed and commissioned to serve ultrafast science experiments and instrumentation development. The system operates at 120-Hz repetition rate with outstanding performance. In this paper, we report on the SLAC MeV UED system and its performance, including the reciprocal space resolution, temporal resolution, and machine stability.

  4. Mega-electron-volt ultrafast electron diffraction at SLAC National Accelerator Laboratory

    SciTech Connect

    Weathersby, S. P.; Brown, G.; Chase, T. F.; Coffee, R.; Corbett, J.; Eichner, J. P.; Frisch, J. C.; Fry, A. R.; Gühr, M.; Hartmann, N.; Hast, C.; Hettel, R.; Jobe, R. K.; Jongewaard, E. N.; Lewandowski, J. R.; Li, R. K. Lindenberg, A. M.; Makasyuk, I.; May, J. E.; McCormick, D.; and others

    2015-07-15

    Ultrafast electron probes are powerful tools, complementary to x-ray free-electron lasers, used to study structural dynamics in material, chemical, and biological sciences. High brightness, relativistic electron beams with femtosecond pulse duration can resolve details of the dynamic processes on atomic time and length scales. SLAC National Accelerator Laboratory recently launched the Ultrafast Electron Diffraction (UED) and microscopy Initiative aiming at developing the next generation ultrafast electron scattering instruments. As the first stage of the Initiative, a mega-electron-volt (MeV) UED system has been constructed and commissioned to serve ultrafast science experiments and instrumentation development. The system operates at 120-Hz repetition rate with outstanding performance. In this paper, we report on the SLAC MeV UED system and its performance, including the reciprocal space resolution, temporal resolution, and machine stability.

  5. Mega-electron-volt ultrafast electron diffraction at SLAC National Accelerator Laboratory

    SciTech Connect

    Weathersby, S. P.; Brown, G.; Centurion, M.; Chase, T. F.; Coffee, R.; Corbett, J.; Eichner, J. P.; Frisch, J. C.; Fry, A. R.; Gühr, M.; Hartmann, N.; Hast, C.; Hettel, R.; Jobe, R. K.; Jongewaard, E. N.; Lewandowski, J. R.; Li, R. K.; Lindenberg, A. M.; Makasyuk, I.; May, J. E.; McCormick, D.; Nguyen, M. N.; Reid, A. H.; Shen, X.; Sokolowski-Tinten, K.; Vecchione, T.; Vetter, S. L.; Wu, J.; Yang, J.; Dürr, H. A.; Wang, X. J.

    2015-07-01

    Ultrafast electron probes are powerful tools, complementary to x-ray free-electron lasers, used to study structural dynamics in material, chemical, and biological sciences. High brightness, relativistic electron beams with femtosecond pulse duration can resolve details of the dynamic processes on atomic time and length scales. SLAC National Accelerator Laboratory recently launched the Ultrafast Electron Diffraction (UED) and microscopy Initiative aiming at developing the next generation ultrafast electron scattering instruments. As the first stage of the Initiative, a mega-electron-volt (MeV) UED system has been constructed and commissioned to serve ultrafast science experiments and instrumentation development. The system operates at 120-Hz repetition rate with outstanding performance. In this paper, we report on the SLAC MeV UED system and its performance, including the reciprocal space resolution, temporal resolution, and machine stability.

  6. Ultrafast laser-driven microlens to focus and energy-select mega-electron volt protons.

    PubMed

    Toncian, Toma; Borghesi, Marco; Fuchs, Julien; d'Humières, Emmanuel; Antici, Patrizio; Audebert, Patrick; Brambrink, Erik; Cecchetti, Carlo Alberto; Pipahl, Ariane; Romagnani, Lorenzo; Willi, Oswald

    2006-04-21

    We present a technique for simultaneous focusing and energy selection of high-current, mega-electron volt proton beams with the use of radial, transient electric fields (10(7) to 10(10) volts per meter) triggered on the inner walls of a hollow microcylinder by an intense subpicosecond laser pulse. Because of the transient nature of the focusing fields, the proposed method allows selection of a desired range out of the spectrum of the polyenergetic proton beam. This technique addresses current drawbacks of laser-accelerated proton beams, such as their broad spectrum and divergence at the source.

  7. Ultralow Energy Electron Attachment at Sub-Millielectron Volt Resolution

    NASA Technical Reports Server (NTRS)

    Chutjian, A.; Kortyna, A.; Darrach, M. R.; Howe, P. -T.

    1999-01-01

    The technique of rare-gas photoionization has been extended by use of direct laser ionization to electron energies epsilon in the range 0-100 meV, with a resolution Delta(epsilon) of 0.4-0.5 meV (FWHM). Tunable UV light at (Lambda)276 nm is produced using a pulsed Nd:YAG laser and nonlinear mixing techniques. The beam is frequency tripled in a pulsed jet of xenon. The VUV radiation, tunable at (Lambda)92 nm, is then used to photoionize Xe at its 2P(sub 1/2) threshold (single-photon ionization). The photoelectrons produced interact with admixed target gas to generate negative ions through the s-wave capture process. Recent results in electron attachment to SF(sub 6) will be reported which show resonance structure at the opening of the ground-state vibrational channels. This structure corresponds to the process of vibrational excitation + attachment, which is superimposed on the underlying s-wave (direct) capture process. It should be a general phenomenon, present in a wide variety of zero-energy electron attaching molecules.

  8. Fast variability of tera-electron volt gamma rays from the radio galaxy M87.

    PubMed

    Aharonian, F; Akhperjanian, A G; Bazer-Bachi, A R; Beilicke, M; Benbow, W; Berge, D; Bernlöhr, K; Boisson, C; Bolz, O; Borrel, V; Braun, I; Brown, A M; Bühler, R; Büsching, I; Carrigan, S; Chadwick, P M; Chounet, L-M; Coignet, G; Cornils, R; Costamante, L; Degrange, B; Dickinson, H J; Djannati-Ataï, A; Drury, L O'c; Dubus, G; Egberts, K; Emmanoulopoulos, D; Espigat, P; Feinstein, F; Ferrero, E; Fiasson, A; Fontaine, G; Funk, Seb; Funk, S; Füssling, M; Gallant, Y A; Giebels, B; Glicenstein, J F; Goret, P; Hadjichristidis, C; Hauser, D; Hauser, M; Heinzelmann, G; Henri, G; Hermann, G; Hinton, J A; Hoffmann, A; Hofmann, W; Holleran, M; Hoppe, S; Horns, D; Jacholkowska, A; de Jager, O C; Kendziorra, E; Kerschhaggl, M; Khélifi, B; Komin, Nu; Konopelko, A; Kosack, K; Lamanna, G; Latham, I J; Le Gallou, R; Lemière, A; Lemoine-Goumard, M; Lenain, J-P; Lohse, T; Martin, J M; Martineau-Huynh, O; Marcowith, A; Masterson, C; Maurin, G; McComb, T J L; Moulin, E; de Naurois, M; Nedbal, D; Nolan, S J; Noutsos, A; Orford, K J; Osborne, J L; Ouchrif, M; Panter, M; Pelletier, G; Pita, S; Pühlhofer, G; Punch, M; Ranchon, S; Raubenheimer, B C; Raue, M; Rayner, S M; Reimer, A; Ripken, J; Rob, L; Rolland, L; Rosier-Lees, S; Rowell, G; Sahakian, V; Santangelo, A; Saugé, L; Schlenker, S; Schlickeiser, R; Schröder, R; Schwanke, U; Schwarzburg, S; Schwemmer, S; Shalchi, A; Sol, H; Spangler, D; Spanier, F; Steenkamp, R; Stegmann, C; Superina, G; Tam, P H; Tavernet, J-P; Terrier, R; Tluczykont, M; van Eldik, C; Vasileiadis, G; Venter, C; Vialle, J P; Vincent, P; Völk, H J; Wagner, S J; Ward, M

    2006-12-01

    The detection of fast variations of the tera-electron volt (TeV) (10(12) eV) gamma-ray flux, on time scales of days, from the nearby radio galaxy M87 is reported. These variations are about 10 times as fast as those observed in any other wave band and imply a very compact emission region with a dimension similar to the Schwarzschild radius of the central black hole. We thus can exclude several other sites and processes of the gamma-ray production. The observations confirm that TeV gamma rays are emitted by extragalactic sources other than blazars, where jets are not relativistically beamed toward the observer.

  9. Direct observation of radiation-belt electron acceleration from electron-volt energies to megavolts by nonlinear whistlers.

    PubMed

    Mozer, F S; Agapitov, O; Krasnoselskikh, V; Lejosne, S; Reeves, G D; Roth, I

    2014-07-18

    The mechanisms for accelerating electrons from thermal to relativistic energies in the terrestrial magnetosphere, on the sun, and in many astrophysical environments have never been verified. We present the first direct observation of two processes that, in a chain, cause this acceleration in Earth's outer radiation belt. The two processes are parallel acceleration from electron-volt to kilovolt energies by parallel electric fields in time-domain structures (TDS), after which the parallel electron velocity becomes sufficiently large for Doppler-shifted upper band whistler frequencies to be in resonance with the electron gyration frequency, even though the electron energies are kilovolts and not hundreds of kilovolts. The electrons are then accelerated by the whistler perpendicular electric field to relativistic energies in several resonant interactions. TDS are packets of electric field spikes, each spike having duration of a few hundred microseconds and containing a local parallel electric field. The TDS of interest resulted from nonlinearity of the parallel electric field component in oblique whistlers and consisted of ∼ 0.1 msec pulses superposed on the whistler waveform with each such spike containing a net parallel potential the order of 50 V. Local magnetic field compression from remote activity provided the free energy to drive the two processes. The expected temporal correlations between the compressed magnetic field, the nonlinear whistlers with their parallel electric field spikes, the electron flux and the electron pitch angle distributions were all observed.

  10. Laser acceleration of electrons to giga-electron-volt energies using highly charged ions.

    PubMed

    Hu, S X; Starace, Anthony F

    2006-06-01

    The recent proposal to use highly charged ions as sources of electrons for laser acceleration [S. X. Hu and A. F. Starace, Phys. Rev. Lett. 88, 245003 (2002)] is investigated here in detail by means of three-dimensional, relativistic Monte Carlo simulations for a variety of system parameters, such as laser pulse duration, ionic charge state, and laser focusing spot size. Realistic laser focusing effects--e.g., the existence of longitudinal laser field components-are taken into account. Results of spatial averaging over the laser focus are also presented. These numerical simulations show that the proposed scheme for laser acceleration of electrons from highly charged ions is feasible with current or near-future experimental conditions and that electrons with GeV energies can be obtained in such experiments.

  11. Image plate characterization and absolute calibration to low kilo-electron-volt electrons

    NASA Astrophysics Data System (ADS)

    Busold, S.; Philipp, K.; Otten, A.; Roth, M.

    2014-11-01

    We report on the characterization of an image plate and its absolute calibration to electrons in the low keV energy range (1-30 keV). In our case, an Agfa MD4.0 without protection layer was used in combination with a Fuji FLA7000 scanner. The calibration data are compared to other published data and a consistent picture of the sensitivity of image plates to electrons is obtained, which suggests a validity of the obtained calibration up to 100 keV.

  12. Image plate characterization and absolute calibration to low kilo-electron-volt electrons.

    PubMed

    Busold, S; Philipp, K; Otten, A; Roth, M

    2014-11-01

    We report on the characterization of an image plate and its absolute calibration to electrons in the low keV energy range (1-30 keV). In our case, an Agfa MD4.0 without protection layer was used in combination with a Fuji FLA7000 scanner. The calibration data are compared to other published data and a consistent picture of the sensitivity of image plates to electrons is obtained, which suggests a validity of the obtained calibration up to 100 keV.

  13. Image plate characterization and absolute calibration to low kilo-electron-volt electrons

    SciTech Connect

    Busold, S.; Philipp, K.; Otten, A.; Roth, M.

    2014-11-15

    We report on the characterization of an image plate and its absolute calibration to electrons in the low keV energy range (1–30 keV). In our case, an Agfa MD4.0 without protection layer was used in combination with a Fuji FLA7000 scanner. The calibration data are compared to other published data and a consistent picture of the sensitivity of image plates to electrons is obtained, which suggests a validity of the obtained calibration up to 100 keV.

  14. FOREWORD: VI Workshop in Electron Volt Neutron Spectroscopy: Frontiers and Horizons

    NASA Astrophysics Data System (ADS)

    Seel, A. G.; Senesi, R.; Fernandez-Alonso, F.

    2014-12-01

    January 2014 saw the congregation in Abingdon (UK) of scientists from across the world, to discuss the current state and future of spectroscopy using epithermal neutrons. This meeting was the sixth in a series of workshops held in collaboration between the Science and Technology Facilities Council (UK) and the Consiglio Nazionale delle Ricerche (Italy), aimed at bringing together researchers with an interest in the use of electron-volt neutrons in spectroscopic studies [1]. This technique is termed Deep Inelastic Neutron Scattering (DINS), and also Neutron Compton Scattering (NCS) in reference to the analogy with Compton scattering of X-rays from electrons. In particular, this meeting centred jointly around experimentalists and theoreticians, formulating animated discussions as to the current overview of DINS and future horizons facing the field. The use of electron Volt neutrons for spectroscopic measurements dates back to the advent of proton-driven spallation neutron sources in the 1970s and 1980s. Following an initial scientific meeting in Los Alamos (USA) [2], the first two meetings in this series were held in Abingdon (UK) in 1995 and 1998, with subsequent meetings held in Santa Fe (USA) in 2005 [3], Oak Ridge National Laboratory (USA) in 2006 [4], and Rome, Italy; in 2010 [5]. The flagship instrument serving a continual user-programme for DINS measurements, and the main focus of this meeting, has been the VESUVIO spectrometer at ISIS [6, 7]. Subsequent instruments like SEQUOIA in the USA [8, 9] and a newer spectrometer in the Bariloche LINAC in Argentina [10, 11] have also been commissioned and began serving a growing user community. The availability of DINS measurements has extended the range of possible spectroscopic techniques that utilise neutrons into the kinematic region of high energy and momentum transfers, shown schematically in Figure 1. Spectroscopic instrument suites such as that of ISIS are thus able to probe processes on timescales across nine

  15. Coherent kilo-electron-volt backscattering from plasma-wave boosted relativistic electron mirrors

    SciTech Connect

    Li, F. Y.; Chen, M. Liu, Y.; Zhang, J.; Sheng, Z. M. E-mail: zmsheng@sjtu.edu.cn; Wu, H. C.; Meyer-ter-Vehn, J.; Mori, W. B.

    2014-10-20

    A different parameter regime of laser wakefield acceleration driven by sub-petawatt femtosecond lasers is proposed, which enables the generation of relativistic electron mirrors further accelerated by the plasma wave. Integrated particle-in-cell simulation, including both the mirror formation and Thomson scattering, demonstrates that efficient coherent backscattering up to keV photon energy can be obtained with moderate driving laser intensities and high density gas targets.

  16. Absolute differential cross sections for electron capture and loss by kilo-electron-volt hydrogen atoms

    NASA Technical Reports Server (NTRS)

    Smith, G. J.; Johnson, L. K.; Gao, R. S.; Smith, K. A.; Stebbings, R. F.

    1991-01-01

    This paper reports measurements of absolute differential cross sections for electron capture and loss for fast hydrogen atoms incident on H2, N2, O2, Ar, and He. Cross sections have been determined in the 2.0- to 5.0-keV energy range over the laboratory angular range 0.02-2 deg, with an angular, resolution of 0.02 deg. The high angular resolution allows observation of the structure at small angles in some of the cross sections. Comparison of the present results with those of other authors generally shows very good agreement.

  17. Backscattering and electron microscopy study of mega-electron volt gold implantation into silicon

    NASA Astrophysics Data System (ADS)

    Alford, T. L.; Theodore, N. David

    1994-12-01

    Rutherford backscattering spectrometry and cross-section transmission electron microscopy have been used to study implantation of MeV Au(+) ions into silicon. Measured range (Rp) and straggle (Delta Rp) values for MeV Au(+) implanted silicon are found to be consistently larger than values predicted by TRIM simulations. The magnitude of the discrepancies are such that the differences cannot be attributed to implantation effects alone. We conclude that the TRIM computer program does not accurately predict Rp and Delta Rp values for MeV Au(+) implantation into crystalline Si. Experimental results show that for low-current low-energy implants a single Gaussian Au profile is achieved. Low-power implants produce a single band of damage consisting of simple point defects. High-current high-energy implants lead to the creation of more complex defect structures such as dislocation networks; these arise as a result of dynamic beam recrystallization. Multiple layers of precipitation are observed in silicon implanted with MeV Au(+) ions in those samples where dynamic recrystallization occurred. Precipitation occurs as a result of the local Au concentration exceeding the solid-solubility during beam-induced recrystallization. Different mechanisms operate in conjunction to cause anomalous Au motion which results in formation of multiple precipitate layers. A first mechanism has the implanted Au segregating into a densely defected region; when the concentration exceeds the local solid solubility Au precipitates out of the matrix. A second mechanism has motion of Au along dislocations in a network; the diffusing Au reaches a dislocation-node where it exceeds the local threshold for precipitation and the Au therefore precipitates. Enhanced Au diffusion is dependent upon the magnitude of dynamic recrystallization occurring during the implantation.

  18. Detection of atomic and molecular mega-electron-volt projectiles using an x-ray charged coupled device camera.

    PubMed

    Chabot, M; Martinet, G; Béroff, K; Pino, T; Bouneau, S; Genolini, B; Grave, X; Nguyen, K; le Gailliard, C; Rosier, P; Féraud, G; Friha, H; Villier, B

    2011-10-01

    We show that an x-ray charge coupled device (CCD) may be used as a particle detector for atomic and molecular mega-electron-volt (MeV) projectiles of around a few hundred keV per atomic mass unit. For atomic species, spectroscopic properties in kinetic energy measurements (i.e., linearity and energy resolution) are found to be close to those currently obtained with implanted or surface barrier silicon particle detectors. For molecular species, in order to increase the maximum kinetic energy detection limit, we propose to put a thin foil in front of the CCD. This foil breaks up the molecules into atoms and spreads the charges over many CCD pixels and therefore avoiding saturation effects. This opens new perspectives in high velocity molecular dissociation studies with accelerator facilities.

  19. Detection of atomic and molecular mega-electron-volt projectiles using an x-ray charged coupled device camera

    SciTech Connect

    Chabot, M.; Martinet, G.; Bouneau, S.; Genolini, B.; Grave, X.; Nguyen, K.; Le Gailliard, C.; Rosier, P.; Beroff, K.; Pino, T.; Feraud, G.; Friha, H.; Villier, B.

    2011-10-15

    We show that an x-ray charge coupled device (CCD) may be used as a particle detector for atomic and molecular mega-electron-volt (MeV) projectiles of around a few hundred keV per atomic mass unit. For atomic species, spectroscopic properties in kinetic energy measurements (i.e., linearity and energy resolution) are found to be close to those currently obtained with implanted or surface barrier silicon particle detectors. For molecular species, in order to increase the maximum kinetic energy detection limit, we propose to put a thin foil in front of the CCD. This foil breaks up the molecules into atoms and spreads the charges over many CCD pixels and therefore avoiding saturation effects. This opens new perspectives in high velocity molecular dissociation studies with accelerator facilities.

  20. Electron-atom superelastic scattering in magnesium at millielectron volt energies.

    PubMed

    Baynard, T; Reber, A C; Niedziela, R F; Darveau, S A; Prutzman, B; Berry, R S

    2007-12-13

    The energy dependence of superelastic scattering is measured for electrons on Mg(3(1)P) from threshold to 270 meV with a novel technique. The method uses photoelectrons produced by a narrow bandwidth laser as an approximately monoenergetic incident electron source to collide with excited atoms. Measurements are made at energies as low as 1.5 meV with a resolution of 1 meV near threshold. An efficient magnetic-bottle time-of-flight electron spectrometer allows for the simultaneous measurement of multiple scattering channels. Above-threshold ionization is also observed. The measured energy dependence for transitions from the 3(1)P state to both the 3(3)P and 3(1)S are found to be inversely proportional to the energy from 10 to 270 meV. Below 10 meV, the dependencies are different, with the 3(3)P transition having an E(-1/2) dependence and the 3(1)S channel retaining an E(-1) dependence.

  1. Characterisation of kilo electron volt neutron fluence standard with the 45Sc(p,n)45Ti reaction at NMIJ.

    PubMed

    Matsumoto, T; Harano, H; Shimoyama, T; Kudo, K; Uritani, A

    2007-01-01

    We are developing a national standard of a monoenergetic kilo electron volt neutron field with the (45)Sc(p,n)(45)Ti resonance reaction. A wide resonance yields 27.4 keV neutrons at 0 degrees with respect to the proton beam. The proton energy was precisely determined in the measurement of the relative neutron yield as a function of the proton energy from the threshold energy to 2.942 MeV. Absolute measurement of the monoenergetic neutron fluence was performed using a (3)He proportional counter. Relative measurement was also carried out using a Bonner sphere calibrated at our 144 keV standard neutron field. Calibration factors were obtained between the count of a neutron monitor and the neutron fluence. A silicon-surface barrier detector with a (6)LiF foil converter was also being developed for the neutron fluence measurement. Successful results were obtained in the tests in the 144 keV standard neutron field.

  2. Planar optical waveguide in Cu-doped potassium sodium strontium barium niobate crystal formed by mega-electron-volt He-ion implantation.

    PubMed

    Lu, F; Meng, M Q; Wang, K M; Liu, X D; Chen, H C; Shen, D Y

    1997-02-01

    The first planar optical waveguide to the authors' knowledge has been formed in Cu-doped potassium sodium strontium barium niobate crystal by mega-electron-volt He(+) implantation. Both TE and TM modes are observed. The profiles of the ordinary and the extraordinary refractive indices are deduced from dark-line mode spectroscopy. The results show that the mega-electron-volt He implantation results in a decrease in refractive index in barriers for both n(o) and n(e), but for n(e) there is an obvious increase in the waveguide region. From an experiment in photorefractive two-wave mixing, it is found that the erasure time for two-wave mixing is prolonged by ion implantation.

  3. Image acquisition with immersion objective lenses using electrons emitted with several tenths of an electron volt energies: towards high spatial resolution ESCA analysis.

    PubMed

    Bernheim, M

    2006-03-01

    This study aims to evaluate the spatial resolution achievable with photoelectrons in order to perform localised UPS or XPS analyses on various heterogeneous samples. This investigation is intentionally restricted to direct image acquisition by immersion objective lenses, involving electrons ejected with initial energies of several tenths of an electron-volt. In order to characterise the contribution of all optical elements, analytical investigations were associated to numerical simulations based on SIMION 7 software. The acquisition of high-quality images implies a simultaneous reduction in spherical and chromatic aberrations by a narrow aperture stop placed at the output pupil of the objective. With such limitations in useful emission angles, it is shown that monochromatic electron beams build images with a resolution of about 1 nm, especially for the acceleration bias mode where the focussing electrode is biased at a positive high voltage. Even energy dispersed electron beams, limited by a 4 eV band pass spectrometer, can produce images convenient for highly localised ESCA analyses (resolution 3 nm), where the objective lens is associated with an aperture stop of 30 microm in diameter without using acceleration voltages above 5000 V.

  4. Missing billions.

    PubMed

    Conly, S

    1997-01-01

    This article discusses funding of population programs that support the Cairo International Conference on Population and Development's Plan of Action. The Plan of Action calls for a quadrupling of annual financial commitments for population programs to $17 billion by the year 2000 and $22 billion by 2015. The increased expenditures would cover the increased demand for services from unmet need and population growth. Donor countries are expected to increase their share from the current 25% to about 33%, or $5.7 billion by the year 2000. The estimates are in 1993 constant dollars. $17 billion is less than the $40 billion that is spent worldwide on playing golf. During 1993-94, general donor support increased to $1.2 billion. Denmark, Germany, Japan, the Netherlands, the United Kingdom, and the United States increased their support. The United States doubled its support for population programs during 1992-95 to $583 million. During 1996-97 the US Congress cut funding back to the 1995 level. France, Italy, Spain, Belgium, and Austria have lagged in support for population programs in the present and the past. Equal burden sharing would require the US to increase funding to $1.9 billion. Developed country assistance declined to the lowest share of combined gross national product since 1970. This shifts the burden to multilateral sources. The European Union is committed to increasing its funding, and the World Bank increased funding for population and reproductive health to about $600 million in 1996 from $424 million in 1994. Bangladesh, China, India, Indonesia, Mexico, South Africa, and Turkey spent 85% of all government expenditures on family planning in developing countries. External donors in Africa are the main support of family planning. Private consumers in Latin America pay most of the costs of family planning. External assistance will be needed for some time.

  5. High quality single shot diffraction patterns using ultrashort megaelectron volt electron beams from a radio frequency photoinjector.

    PubMed

    Musumeci, P; Moody, J T; Scoby, C M; Gutierrez, M S; Bender, H A; Wilcox, N S

    2010-01-01

    Single shot diffraction patterns using a 250-fs-long electron beam have been obtained at the UCLA Pegasus laboratory. High quality images with spatial resolution sufficient to distinguish closely spaced peaks in the Debye-Scherrer ring pattern have been recorded by scattering the 1.6 pC 3.5 MeV electron beam generated in the rf photoinjector off a 100-nm-thick Au foil. Dark current and high emittance particles are removed from the beam before sending it onto the diffraction target using a 1 mm diameter collimating hole. These results open the door to the study of irreversible phase transformations by single shot MeV electron diffraction.

  6. High quality single shot diffraction patterns using ultrashort megaelectron volt electron beams from a radio frequency photoinjector

    SciTech Connect

    Musumeci, P.; Moody, J. T.; Scoby, C. M.; Gutierrez, M. S.; Bender, H. A.; Wilcox, N. S.

    2010-01-15

    Single shot diffraction patterns using a 250-fs-long electron beam have been obtained at the UCLA Pegasus laboratory. High quality images with spatial resolution sufficient to distinguish closely spaced peaks in the Debye-Scherrer ring pattern have been recorded by scattering the 1.6 pC 3.5 MeV electron beam generated in the rf photoinjector off a 100-nm-thick Au foil. Dark current and high emittance particles are removed from the beam before sending it onto the diffraction target using a 1 mm diameter collimating hole. These results open the door to the study of irreversible phase transformations by single shot MeV electron diffraction.

  7. High Quality Single Shot Diffraction Patterns Using Ultrashort Megaelectron Volt Electron Beams from a Radio Frequency Photoinjector

    SciTech Connect

    P. Musumeci, J. T. Moody, C. M. Scoby, M. S. Gutierrez, H. A. Bender, N. S. Wilcox

    2010-01-01

    Single shot diffraction patterns using a 250 fs long electron beam have been obtained at the UCLA Pegasus laboratory. High quality images with spatial resolution sufficient to distinguish closely spaced peaks in the Debye-Scherrer ring pattern have been recorded by scattering the 1.6 pC 3.5 MeV electron beam generated in the RF photoinjector off a 100 nm thick Au foil. Dark current and high emittance particles are removed from the beam before sending it onto the diffraction target using a 1 mm diameter collimating hole. These results open the door to the study of irreversible phase transformations by single shot MeV electron diffraction

  8. Generation of high-quality mega-electron volt proton beams with intense-laser-driven nanotube accelerator

    SciTech Connect

    Murakami, M.; Tanaka, M.

    2013-04-22

    An ion acceleration scheme using carbon nanotubes (CNTs) is proposed, in which embedded fragments of low-Z materials are irradiated by an ultrashort intense laser to eject substantial numbers of electrons. Due to the resultant characteristic electrostatic field, the nanotube and embedded materials play the roles of the barrel and bullets of a gun, respectively, to produce highly collimated and quasimonoenergetic ion beams. Three-dimensional particle simulations, that take all the two-body Coulomb interactions into account, demonstrate generation of quasimonoenergetic MeV-order proton beams using nanometer-size CNT under a super-intense electrostatic field {approx}10{sup 14} V m{sup -1}.

  9. Constraint on a varying proton-electron mass ratio 1.5 billion years after the big bang.

    PubMed

    Bagdonaite, J; Ubachs, W; Murphy, M T; Whitmore, J B

    2015-02-20

    A molecular hydrogen absorber at a lookback time of 12.4 billion years, corresponding to 10% of the age of the Universe today, is analyzed to put a constraint on a varying proton-electron mass ratio, μ. A high resolution spectrum of the J1443+2724 quasar, which was observed with the Very Large Telescope, is used to create an accurate model of 89 Lyman and Werner band transitions whose relative frequencies are sensitive to μ, yielding a limit on the relative deviation from the current laboratory value of Δμ/μ=(-9.5 ± 5.4(stat)± 5.3(syst))×10(-6).

  10. Hard x-ray monochromator with milli-electron volt bandwidth for high-resolution diffraction studies of diamond crystals

    SciTech Connect

    Stoupin, Stanislav; Shvyd'ko, Yuri; Shu Deming; Khachatryan, Ruben; Xiao, Xianghui; DeCarlo, Francesco; Goetze, Kurt; Roberts, Timothy; Roehrig, Christian; Deriy, Alexey

    2012-02-15

    We report on design and performance of a high-resolution x-ray monochromator with a spectral bandwidth of {Delta}E{sub X}{approx_equal} 1.5 meV, which operates at x-ray energies in the vicinity of the backscattering (Bragg) energy E{sub H} = 13.903 keV of the (008) reflection in diamond. The monochromator is utilized for high-energy-resolution diffraction characterization of diamond crystals as elements of advanced x-ray crystal optics for synchrotrons and x-ray free-electron lasers. The monochromator and the related controls are made portable such that they can be installed and operated at any appropriate synchrotron beamline equipped with a pre-monochromator.

  11. Hard x-ray monochromator with milli-electron volt bandwidth for high-resolution diffraction studies of diamond crystals.

    PubMed

    Stoupin, Stanislav; Shvyd'ko, Yuri; Shu, Deming; Khachatryan, Ruben; Xiao, Xianghui; DeCarlo, Francesco; Goetze, Kurt; Roberts, Timothy; Roehrig, Christian; Deriy, Alexey

    2012-02-01

    We report on design and performance of a high-resolution x-ray monochromator with a spectral bandwidth of ΔE(X) ≃ 1.5 meV, which operates at x-ray energies in the vicinity of the backscattering (Bragg) energy E(H) = 13.903 keV of the (008) reflection in diamond. The monochromator is utilized for high-energy-resolution diffraction characterization of diamond crystals as elements of advanced x-ray crystal optics for synchrotrons and x-ray free-electron lasers. The monochromator and the related controls are made portable such that they can be installed and operated at any appropriate synchrotron beamline equipped with a pre-monochromator.

  12. Hard x-ray monochromator with milli-electron volt bandwidth for high-resolution diffraction studies of diamond crystals.

    SciTech Connect

    Stoupin, S.; Shvydko, Y.; Shu, D.; Khachatryan, R.; Xiao, X.

    2012-01-01

    We report on design and performance of a high-resolution x-ray monochromator with a spectral bandwidth of {Delta}E{sub x} {approx_equal} 1.5 meV, which operates at x-ray energies in the vicinity of the backscattering (Bragg) energy E{sub H} = 13.903 keV of the (008) reflection in diamond. The monochromator is utilized for high-energy-resolution diffraction characterization of diamond crystals as elements of advanced x-ray crystal optics for synchrotrons and x-ray free-electron lasers. The monochromator and the related controls are made portable such that they can be installed and operated at any appropriate synchrotron beamline equipped with a pre-monochromator.

  13. Ion explosion and multi-mega-electron-volt ion generation from an underdense plasma layer irradiated by a relativistically intense short-pulse laser.

    PubMed

    Yamagiwa, M; Koga, J; Tsintsadze, L N; Ueshima, Y; Kishimoto, Y

    1999-11-01

    Ion acceleration and expansion in the interaction of a relativistically intense short-pulse laser with an underdense plasma layer are investigated. Ion and electron dynamics are studied by a two-dimensional particle-in-cell simulation with the real mass ratio. It is shown that the longitudinal electric field induced by electron evacuation due to a large ponderomotive force or light pressure can accelerate ions to several MeV in the direction of the laser propagation. It is after the laser completely passes through the plasma layer that the ion explosion starts to be significant.

  14. The ExaVolt Antenna

    NASA Astrophysics Data System (ADS)

    Dailey, Brian

    2014-03-01

    There are strong motivations for a flux of ultra-high energy (UHE) neutrinos that is observable on earth, yet they remain undetected. The proposed ExaVolt Antenna (EVA) uses a novel approach to increase the expected rate of neutrinos in a balloon-borne experiment such as ANITA by 100-fold by turning a 100m-diameter, long-duration, super pressure NASA balloon into an antenna reflector with receivers deployed in the interior of the balloon. EVA would be the world's largest airborne telescope with ~ 1000 m2 of collection area. I will present preliminary results from a 1:20 scale EVA prototype test conducted in early 2014 in a hangar at NASA's Wallops Flight Facility. I will conclude with the expected sensitivity of the full EVA experiment to UHE neutrino fluxes.

  15. Development of the VOLT-A Shuttle experiment. [Volt Operating Limit Tests

    NASA Technical Reports Server (NTRS)

    Bifano, William J.; Bozek, John M.; Ferguson, Dale C.

    1985-01-01

    The NASA Lewis Research Center (LeRC) is investigating potential problems associated with the operation of high voltage solar cell arrays in the space plasma environment. At high voltages, interactions between the solar array and the space plasma could result in unacceptable levels of electrical discharge (arcing) and/or parasitic losses (current drains from the array to the plasma). The objective of the Voltage Operating Limit Tests (VOLT-A) Shuttle bay experiment is to characterize space plasma/solar cell panel interactions in low earth orbit. VOLT-A consists of an experiment plate subassembly which contains four solar panels, an electronics subassembly and a Langmuir probe subassembly mounted on an MPESS carrier. During a given 8.25 hour data taking period (5-1/2 continuous orbits), the solar panels, which represent state-of-the-art solar cell technologies, will be sequentially subjected to bias voltages in steps ranging from minus 626 V to plus 313 V. Appropriate measurements will be made at each voltage to characterize arcing and parasitic losses. Corresponding measurements of the plasma environment (plasma density, electron temperature and neutral density) will also be made. Data will be recorded on an on-board tape recorder for subsequent data reduction and analysis.

  16. Nine billion or bust?

    NASA Astrophysics Data System (ADS)

    nerd, nerd; Pepperday, Mike; Szautner, a. a. z.

    2014-02-01

    In reply to a review of Tony Ryan and Steve McKevitt's book Project Sunshine, which explores ways in which the Earth could support a future population of nine billion people (Letting the sunshine in, November 2013 pp50-51, http://ow.ly/r0FTM).

  17. Steady State Load Characterization Fact Sheet: 2012 Chevy Volt

    SciTech Connect

    Scoffield, Don

    2015-03-01

    This fact sheet characterizes the steady state charging behavior of a 2012 Chevy Volt. Both level 1 charging (120 volt) and level 2 charging (208 volts) is investigated. This fact sheet contains plots of efficiency, power factor, and current harmonics as vehicle charging is curtailed. Prominent current harmonics are also displayed in a histogram for various charge rates.

  18. Development of the VOLT-A shuttle experiment

    NASA Technical Reports Server (NTRS)

    Bifano, W. J.; Bozek, J. M.; Ferguson, D. C.

    1985-01-01

    The NASA Lewis Research Center (LeRC) is investigating potential problems associated with the operation of high voltage solar cell arrays in the space plasma environment. At high voltages, interactions between the solar array and the space plasma could result in unacceptable levels of electrical discharge (arcing) and/or parasitic losses (current drains from the array to the plasma). The objective of the Voltage Operating Limit Tests (VOLT-A) Shuttle bay experiment is to characterize space plasma/solar cell panel interactions in low earth orbit. VOLT-A consists of an experiment plate subassembly which contains four solar panels, an electronics subassembly and a Langmuir probe subassembly mounted on an MPESS carrier. During a given 8.25 hour data taking period (5-1/2 continuous orbits), the solar panels, which represent state-of-the-art solar cell technologies, will be sequentially subjected to bias voltages in steps ranging from minus 626 V to plus 313 V. Appropriate measurements will be made at each voltage to characterize arcing and parasitic losses. Corresponding measurements of the plasma environment (plasma density, electron temperature and neutral density) will also be made. Data will be recorded on an on-board tape recorder for subsequent data reduction and analysis.

  19. 137. POWER PANEL A (208 VOLTS) AND POWER PANEL B ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    137. POWER PANEL A (208 VOLTS) AND POWER PANEL B (480 VOLTS) ON EAST WALL OF TRANSFORMER ROOM (212), LSB (BLDG. 751) - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  20. World population beyond six billion.

    PubMed

    Gelbard, A; Haub, C; Kent, M M

    1999-03-01

    This world report reviews population growth pre-1900, population change during 1900-50 and 1950-2000, causes and effects of population change and projections to 2050. World population grew from 2 billion in 1900 to almost 6 billion in 2000. Population showed more rapid growth in the 17th and 18th centuries. Better hygiene and public sanitation in the 19th century led to expanded life expectancies and quicker growth, primarily in developed countries. Demographic transition in the 19th and 20th centuries was the result of shifts from high to low mortality and fertility. The pace of change varies with culture, level of economic development, and other factors. Not all countries follow the same path of change. The reproductive revolution in the mid-20th century and modern contraception led to greater individual control of fertility and the potential for rapid fertility decline. Political and cultural barriers that limit access affect the pace of decline. Population change is also affected by migration. Migration has the largest effect on the distribution of population. Bongaarts explains differences in fertility by the proportion in unions, contraceptive prevalence, infertility, and abortion. Educational status has a strong impact on adoption of family planning. Poverty is associated with multiple risks. In 2050, population could reach 10.7 billion or remain low at 7.3 billion.

  1. FRONTAL VIEW OF #3 GENERATOR, 6600 VOLT OIL CIRCUIT BREAKER, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    FRONTAL VIEW OF #3 GENERATOR, 6600 VOLT OIL CIRCUIT BREAKER, LOCATED BEHIND SLATE SWITCHBOARD. PHOTO BY JET LOWE, HAER, 1995. - Elwha River Hydroelectric System, Elwha Hydroelectric Dam & Plant, Port Angeles, Clallam County, WA

  2. Chandra Examines a Quadrillion-Volt Pulsar

    NASA Astrophysics Data System (ADS)

    2001-09-01

    The high-voltage environment of one of the most energetic and strongly magnetized pulsars known has been surveyed by NASA's Chandra X-ray Observatory. A team of astronomers found a powerful jet of high-energy particles extending over a distance of 20 light years and bright arcs believed to be due to particles of matter and anti-matter generated by the pulsar. The team of US, Canadian, and Japanese scientists pointed Chandra at the rapidly spinning neutron star B1509-58, located 19,000 light years away in the constellation of Circinus, for over five hours. These results were announced at the "Two Years of Science with Chandra" symposium in Washington, DC. "Jets and arcs on this vast scale have never been seen in any other pulsar," said Bryan Gaensler of the Smithsonian Astrophysical Observatory. "The spectacular images we have obtained of this source are letting us test theories as to how pulsars unleash so much energy." The features seen with Chandra give the scientists insight into the process by which voltages of more than 7000 trillion volts are created around rotating neutron stars (the dense remnants of supernova explosions) and how these extreme voltages affect their environment. B1509-58 is of particular interest because it has a much stronger magnetic field than the Crab Nebula pulsar, which exhibits similar features on a much smaller scale. The general picture emerging from these results is that high-energy particles of matter and antimatter are streaming away from the neutron star along its poles and near its equator. The particles leaving the poles produce the jets; astronomers speculate that only one side of the jet is apparent in B1509-58, indicating that this one side is beamed in our direction, while the other is rushing away. "Until this observation, no one knew for sure whether such tremendous voltages and energy outputs were a trademark of all pulsars, or if the Crab was an oddball," said Vicky Kaspi of McGill University in Montreal. "Now thanks

  3. A Method for Evaluating Volt-VAR Optimization Field Demonstrations

    SciTech Connect

    Schneider, Kevin P.; Weaver, T. F.

    2014-08-31

    In a regulated business environment a utility must be able to validate that deployed technologies provide quantifiable benefits to the end-use customers. For traditional technologies there are well established procedures for determining what benefits will be derived from the deployment. But for many emerging technologies procedures for determining benefits are less clear and completely absent in some cases. Volt-VAR Optimization is a technology that is being deployed across the nation, but there are still numerous discussions about potential benefits and how they are achieved. This paper will present a method for the evaluation, and quantification of benefits, for field deployments of Volt-VAR Optimization technologies. In addition to the basic methodology, the paper will present a summary of results, and observations, from two separate Volt-VAR Optimization field evaluations using the proposed method.

  4. Life: the first two billion years.

    PubMed

    Knoll, Andrew H; Bergmann, Kristin D; Strauss, Justin V

    2016-11-05

    Microfossils, stromatolites, preserved lipids and biologically informative isotopic ratios provide a substantial record of bacterial diversity and biogeochemical cycles in Proterozoic (2500-541 Ma) oceans that can be interpreted, at least broadly, in terms of present-day organisms and metabolic processes. Archean (more than 2500 Ma) sedimentary rocks add at least a billion years to the recorded history of life, with sedimentological and biogeochemical evidence for life at 3500 Ma, and possibly earlier; phylogenetic and functional details, however, are limited. Geochemistry provides a major constraint on early evolution, indicating that the first bacteria were shaped by anoxic environments, with distinct patterns of major and micronutrient availability. Archean rocks appear to record the Earth's first iron age, with reduced Fe as the principal electron donor for photosynthesis, oxidized Fe the most abundant terminal electron acceptor for respiration, and Fe a key cofactor in proteins. With the permanent oxygenation of the atmosphere and surface ocean ca 2400 Ma, photic zone O2 limited the access of photosynthetic bacteria to electron donors other than water, while expanding the inventory of oxidants available for respiration and chemoautotrophy. Thus, halfway through Earth history, the microbial underpinnings of modern marine ecosystems began to take shape.This article is part of the themed issue 'The new bacteriology'.

  5. 5.5 billion -- and growing.

    PubMed

    Robey, B

    1992-07-17

    On World Population Day in 1992 the total world population reached 5.5 billion, 100 million more than on July 11, 1991, and it is expected to pass the 6 billion figure by 2000. In developed countries the average number of children is 2/family, while in developing countries the norm is 4 children, a substantial drop from 6 children in the 1960s. The 2 billion level was reached in 1930, the world population doubled from 1 billion in 100 years. The billion mark in 1960 took only 30 years, the 4 billion figure was reached in 1975 in only 15 years, and to grow to 5 billion in 1987 took only 12 years. A 20-year delay to reach replacement level adds another 1 billion to the population size. If the 2-children-per family size had been reached in 1990, the total would still have increased to 8 billion by 2100. Provided the present trend of 3.4 children/couple continues, there will be 102 billion people in 2100. Some claim that the resources of the Earth are already overtaxed with ever-worsening environmental pollution. Family planning information and services have to me made available to those millions who want to avoid pregnancy and ensure a better future for fewer children.

  6. Life with Four Billion Atoms

    SciTech Connect

    Knight, Thomas

    2013-04-10

    Today it is commonplace to design and construct single silicon chips with billions of transistors. These are complex systems, difficult (but possible) to design, test, and fabricate. Remarkably, simple living systems can be assembled from a similar number of atoms, most of them in water molecules. In this talk I will present the current status of our attempts at full understanding and complexity reduction of one of the simplest living systems, the free-living bacterial species Mesoplasma florum. This 400 nm diameter cell thrives and replicates every 40 minutes with a genome of only 800 kilobases. Our recent experiments using transposon gene knockouts identified 354 of 683 annotated genes as inessential in laboratory culture when inactivated individually. While a functional redesigned genome will certainly not remove all of those genes, this suggests that roughly half the genome can be removed in an intentional redesign. I will discuss our recent knockout results and methodology, and our future plans for Genome re-engineering using targeted knock-in/knock-out double recombination; whole cell metabolic models; comprehensive whole cell metabolite measurement techniques; creation of plug-and-play metabolic modules for the simplified organism; inherent and engineered biosafety control mechanisms. This redesign is part of a comprehensive plan to lay the foundations for a new discipline of engineering biology. Engineering biological systems requires a fundamentally different viewpoint from that taken by the science of biology. Key engineering principles of modularity, simplicity, separation of concerns, abstraction, flexibility, hierarchical design, isolation, and standardization are of critical importance. The essence of engineering is the ability to imagine, design, model, build, and characterize novel systems to achieve specific goals. Current tools and components for these tasks are primitive. Our approach is to create and distribute standard biological parts

  7. Plant Generator driven by a small Delco 32 volt DC ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Plant Generator driven by a small Delco 32 volt DC steam engine with a maximum output of 17.6 kilowatts - East Broad Top Railroad & Coal Company, Machine Shop, State Route 994, West of U.S. Route 522, Rockhill Furnace, Huntingdon County, PA

  8. 14. BREAKER 7 GENERATOR 20: A 7000 VOLT 1200 AMPERES ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. BREAKER 7 GENERATOR 20: A 7000 VOLT 1200 AMPERES BREAKER. IT WEIGHS 1630 POUNDS. (GENERATOR 20 IS LOCATED AT NEWHALEM POWERHOUSE BUT IS REMOTE CONTROLLED FROM GORGE POWERHOUSE.) 1989. - Skagit Power Development, Gorge Powerhouse, On Skagit River, 0.4 mile upstream from Newhalem, Newhalem, Whatcom County, WA

  9. Zero Volt Paper Spray Ionization and Its Mechanism.

    PubMed

    Wleklinski, Michael; Li, Yafeng; Bag, Soumabha; Sarkar, Depanjan; Narayanan, Rahul; Pradeep, T; Cooks, R Graham

    2015-07-07

    The analytical performance and a suggested mechanism for zero volt paper spray using chromatography paper are presented. A spray is generated by the action of the pneumatic force of the mass spectrometer (MS) vacuum at the inlet. Positive and negative ion signals are observed, and comparisons are made with standard kV paper spray (PS) ionization and nanoelectrospray ionization (nESI). While the range of analytes to which zero volt PS is applicable is very similar to kV PS and nESI, differences in the mass spectra of mixtures are interpreted in terms of the more significant effects of analyte surface activity in the gentler zero volt experiment than in the other methods due to the significantly lower charge. The signal intensity of zero volt PS is also lower than in the other methods. A Monte Carlo simulation based on statistical fluctuation of positive and negative ions in solution has been implemented to explain the production of ions from initially uncharged droplets. Uncharged droplets first break up due to aerodynamics forces until they are in the 2-4 μm size range and then undergo Coulombic fission. A model involving statistical charge fluctuations in both phases predicts detection limits similar to those observed experimentally and explains the effects of binary mixture components on relative ionization efficiencies. The proposed mechanism may also play a role in ionization by other voltage-free methods.

  10. 50. PARTIAL FLOOR PLAN SHOWING INDOOR 750 VOLT SWITCHRACK AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    50. PARTIAL FLOOR PLAN SHOWING INDOOR 750 VOLT SWITCHRACK AND MISC. EQUIPMENT, SANTA ANA RIVER NO. 2, DEC. 11, 1951; REVISIONS, DEC. 14, 1951. SCE drawing no. 534985-1. - Santa Ana River Hydroelectric System, SAR-2 Powerhouse, Redlands, San Bernardino County, CA

  11. 59. View of high voltage (4160 volts alternating current) electric ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    59. View of high voltage (4160 volts alternating current) electric load center and motor control center at mezzanine level in transmitter building no. 102. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

  12. One-volt operation of high-current vertical channel polymer semiconductor field-effect transistors.

    PubMed

    Johnston, Danvers E; Yager, Kevin G; Nam, Chang-Yong; Ocko, Benjamin M; Black, Charles T

    2012-08-08

    We realize a vertical channel polymer semiconductor field effect transistor architecture by confining the organic material within gratings of interdigitated trenches. The geometric space savings of a perpendicular channel orientation results in devices sourcing areal current densities in excess of 40 mA/cm(2), using a one-volt supply voltage, and maintaining near-ideal device operating characteristics. Vertical channel transistors have a similar electronic mobility to that of planar devices using the same polymer semiconductor, consistent with a molecular reorientation within confining trenches we understand through X-ray scattering measurements.

  13. Countdown to Six Billion Teaching Kit.

    ERIC Educational Resources Information Center

    Zero Population Growth, Inc., Washington, DC.

    This teaching kit features six activities focused on helping students understand the significance of the world population reaching six billion for our society and our environment. Featured activities include: (1) History of the World: Part Six Billion; (2) A Woman's Place; (3) Baby-O-Matic; (4) Earth: The Apple of Our Eye; (5) Needs vs. Wants; and…

  14. Spend Billions and They Will Come

    ERIC Educational Resources Information Center

    Fox, Bette-Lee

    2004-01-01

    People look at one billion dollars in one of two ways: if it is the result of the long, hard effort of years of fundraising, they rejoice; if it signifies an astronomical budget deficit, they cringe. How, then, should people respond as a community to reaching the $1 billion mark ($1,242,436,438, to be exact) in this year's spending for public…

  15. 33 CFR 183.430 - Conductors in circuits of less than 50 volts.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... than 50 volts. 183.430 Section 183.430 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF... Requirements § 183.430 Conductors in circuits of less than 50 volts. (a) Each conductor in a circuit that has a nominal voltage of less than 50 volts must: (1) Meet the requirements of § 183.435; or (2) Meet: (i)...

  16. 33 CFR 183.430 - Conductors in circuits of less than 50 volts.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... than 50 volts. 183.430 Section 183.430 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF... Requirements § 183.430 Conductors in circuits of less than 50 volts. (a) Each conductor in a circuit that has a nominal voltage of less than 50 volts must: (1) Meet the requirements of § 183.435; or (2) Meet: (i)...

  17. 33 CFR 183.430 - Conductors in circuits of less than 50 volts.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... than 50 volts. 183.430 Section 183.430 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF... Requirements § 183.430 Conductors in circuits of less than 50 volts. (a) Each conductor in a circuit that has a nominal voltage of less than 50 volts must: (1) Meet the requirements of § 183.435; or (2) Meet: (i)...

  18. 33 CFR 183.435 - Conductors in circuits of 50 volts or more.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... volts or more. 183.435 Section 183.435 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF... Requirements § 183.435 Conductors in circuits of 50 volts or more. (a) Each conductor in a circuit that has a nominal voltage of 50 volts or more must be: (1) A conductor that has insulation listed and...

  19. 75 FR 76040 - Weyerhaeuser Company Corporate Headquarters Including On-Site Leased Workers From Volt Services...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-07

    ... Workers From Volt Services, Adecco, Manpower and Express Personnel Federal Way, Washington; Amended... Weyerhaeuser Company, Corporate Headquarters, including on-site leased workers from Volt Services, Adecco, and... Volt Services, Adecco, Manpower, and Express Personnel, Federal Way, Washington, who became totally...

  20. 33 CFR 183.430 - Conductors in circuits of less than 50 volts.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... than 50 volts. 183.430 Section 183.430 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF... Requirements § 183.430 Conductors in circuits of less than 50 volts. (a) Each conductor in a circuit that has a nominal voltage of less than 50 volts must: (1) Meet the requirements of § 183.435; or (2) Meet: (i)...

  1. Americans Are Spending Billions Nipping and Tucking

    MedlinePlus

    ... Tucking New report details costs of most popular plastic surgery procedures To use the sharing features on ... A new report from the American Society of Plastic Surgeons (ASPS) found that Americans spent $16 billion ...

  2. Saturation and negative differential resistance in volt-ampere characteristics of the photocurrent in CdSe films

    SciTech Connect

    Smyntyna, V.A.

    1987-01-01

    The manifestation of the saturation- and negative-differential-resistance-parts in the volt-ampere characteristics of cadmium selenide films is due to the formation of chemisorbed, electrical domains, stimulated by Joule heating of the films. Increase in the sample temperature on account of external heating leads to decrease in the power given off in the sample, at which the chemisorption process is activated. An investigation of the volt-ampere characteristics at different temperatures and at different wavelengths of the primary illumination showed that the domains, mentioned above, are formed on the surface of the samples investigated as a result of the trapping of electrons from the conduction band at the chemisorbed oxygen level.

  3. Atmospheric oxygenation three billion years ago.

    PubMed

    Crowe, Sean A; Døssing, Lasse N; Beukes, Nicolas J; Bau, Michael; Kruger, Stephanus J; Frei, Robert; Canfield, Donald E

    2013-09-26

    It is widely assumed that atmospheric oxygen concentrations remained persistently low (less than 10(-5) times present levels) for about the first 2 billion years of Earth's history. The first long-term oxygenation of the atmosphere is thought to have taken place around 2.3 billion years ago, during the Great Oxidation Event. Geochemical indications of transient atmospheric oxygenation, however, date back to 2.6-2.7 billion years ago. Here we examine the distribution of chromium isotopes and redox-sensitive metals in the approximately 3-billion-year-old Nsuze palaeosol and in the near-contemporaneous Ijzermyn iron formation from the Pongola Supergroup, South Africa. We find extensive mobilization of redox-sensitive elements through oxidative weathering. Furthermore, using our data we compute a best minimum estimate for atmospheric oxygen concentrations at that time of 3 × 10(-4) times present levels. Overall, our findings suggest that there were appreciable levels of atmospheric oxygen about 3 billion years ago, more than 600 million years before the Great Oxidation Event and some 300-400 million years earlier than previous indications for Earth surface oxygenation.

  4. Particle physicist's dreams about PetaelectronVolt laser plasma accelerators

    SciTech Connect

    Vesztergombi, G.

    2012-07-09

    Present day accelerators are working well in the multi TeV energy scale and one is expecting exciting results in the coming years. Conventional technologies, however, can offer only incremental (factor 2 or 3) increase in beam energies which does not follow the usual speed of progress in the frontiers of high energy physics. Laser plasma accelerators theoretically provide unique possibilities to achieve orders of magnitude increases entering the PetaelectronVolt (PeV) energy range. It will be discussed what kind of new perspectives could be opened for the physics at this new energy scale. What type of accelerators would be required?.

  5. Matter-antimatter gigaelectron volt gamma ray laser rocket propulsion

    NASA Astrophysics Data System (ADS)

    Winterberg, F.

    2012-12-01

    It is shown that the idea of a photon rocket through the complete annihilation of matter with antimatter, first proposed by Sänger, is not a utopian scheme as it is widely believed. Its feasibility appears to be possible by the radiative collapse of a relativistic high current pinch discharge in a hydrogen-antihydrogen ambiplasma down to a radius determined by Heisenberg's uncertainty principle. Through this collapse to ultrahigh densities the proton-antiproton pairs in the center of the pinch can become the upper gigaelectron volt laser level for the transition into a coherent gamma ray beam by proton-antiproton annihilation, with the magnetic field of the collapsed pinch discharge absorbing the recoil momentum of the beam and transmitting it by the Moessbauer effect to the spacecraft. The gamma ray laser beam is launched as a photon avalanche from one end of the pinch discharge channel. Because of the enormous technical problems to produce and store large amounts of anti-matter, such a propulsion concept may find its first realization in small unmanned space probes to explore nearby solar systems. The laboratory demonstration of a gigaelectron volt gamma ray laser by comparison requiring small amounts of anti-matter may be much closer.

  6. Field emission electron source

    DOEpatents

    Zettl, Alexander Karlwalter; Cohen, Marvin Lou

    2000-01-01

    A novel field emitter material, field emission electron source, and commercially feasible fabrication method is described. The inventive field emission electron source produces reliable electron currents of up to 400 mA/cm.sup.2 at 200 volts. The emitter is robust and the current it produces is not sensitive to variability of vacuum or the distance between the emitter tip and the cathode. The novel emitter has a sharp turn-on near 100 volts.

  7. Four billion people facing severe water scarcity

    PubMed Central

    Mekonnen, Mesfin M.; Hoekstra, Arjen Y.

    2016-01-01

    Freshwater scarcity is increasingly perceived as a global systemic risk. Previous global water scarcity assessments, measuring water scarcity annually, have underestimated experienced water scarcity by failing to capture the seasonal fluctuations in water consumption and availability. We assess blue water scarcity globally at a high spatial resolution on a monthly basis. We find that two-thirds of the global population (4.0 billion people) live under conditions of severe water scarcity at least 1 month of the year. Nearly half of those people live in India and China. Half a billion people in the world face severe water scarcity all year round. Putting caps to water consumption by river basin, increasing water-use efficiencies, and better sharing of the limited freshwater resources will be key in reducing the threat posed by water scarcity on biodiversity and human welfare. PMID:26933676

  8. Four billion people facing severe water scarcity.

    PubMed

    Mekonnen, Mesfin M; Hoekstra, Arjen Y

    2016-02-01

    Freshwater scarcity is increasingly perceived as a global systemic risk. Previous global water scarcity assessments, measuring water scarcity annually, have underestimated experienced water scarcity by failing to capture the seasonal fluctuations in water consumption and availability. We assess blue water scarcity globally at a high spatial resolution on a monthly basis. We find that two-thirds of the global population (4.0 billion people) live under conditions of severe water scarcity at least 1 month of the year. Nearly half of those people live in India and China. Half a billion people in the world face severe water scarcity all year round. Putting caps to water consumption by river basin, increasing water-use efficiencies, and better sharing of the limited freshwater resources will be key in reducing the threat posed by water scarcity on biodiversity and human welfare.

  9. Great Plains makes 100 billion cubic feet

    SciTech Connect

    Not Available

    1987-03-01

    The Great Plains coal gasification plant on January 18, 1987 produced its 100 billionth cubic foot of gas since start-up July 28, 1984. Owned by the Department of Energy and operated by ANG Coal Gasification Company, the plant uses the Lurgi process to produce about 50 billion cubic feet per year of gas from five million tons per year of lignite. The plant has been performing at well above design capacity.

  10. Teledesic pushes $9-billion, 900-satellite system

    NASA Astrophysics Data System (ADS)

    1994-03-01

    Teledesic Corp. is seeking FCC approval to deploy a communication satellite system, costing $9 billion and using more than 900 satellites in low Earth orbit. This system would provide telephone and broadband data service to remote areas and developing countries. The two major stockholders in Teledesic are William Gates (of Microsoft Corp.) and Craig McCaw (of McCaw Cellular Communications). Each satellite would act as a node in a packet-switching network. The satellites would provide continuous global coverage.

  11. What kind of charging infrastructure do Chevrolet Volts Drivers in The EV Project use?

    SciTech Connect

    John Smart

    2013-09-01

    This report summarizes key conclusions from analysis of data collected from Chevrolet Volts participating in The EV Project. Topics include how much Volt drivers charge at level 1 vs. level 2 rates and how much they charge at home vs. away from home.

  12. 33 CFR 183.435 - Conductors in circuits of 50 volts or more.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Conductors in circuits of 50... Requirements § 183.435 Conductors in circuits of 50 volts or more. (a) Each conductor in a circuit that has a nominal voltage of 50 volts or more must be: (1) A conductor that has insulation listed and...

  13. Observation of acceleration and deceleration in gigaelectron-volt-per-metre gradient dielectric wakefield accelerators

    PubMed Central

    O'Shea, B. D.; Andonian, G.; Barber, S. K.; Fitzmorris, K. L.; Hakimi, S.; Harrison, J.; Hoang, P. D.; Hogan, M. J.; Naranjo, B.; Williams, O. B.; Yakimenko, V.; Rosenzweig, J. B.

    2016-01-01

    There is urgent need to develop new acceleration techniques capable of exceeding gigaelectron-volt-per-metre (GeV m−1) gradients in order to enable future generations of both light sources and high-energy physics experiments. To address this need, short wavelength accelerators based on wakefields, where an intense relativistic electron beam radiates the demanded fields directly into the accelerator structure or medium, are currently under intense investigation. One such wakefield based accelerator, the dielectric wakefield accelerator, uses a dielectric lined-waveguide to support a wakefield used for acceleration. Here we show gradients of 1.347±0.020 GeV m−1 using a dielectric wakefield accelerator of 15 cm length, with sub-millimetre transverse aperture, by measuring changes of the kinetic state of relativistic electron beams. We follow this measurement by demonstrating accelerating gradients of 320±17 MeV m−1. Both measurements improve on previous measurements by and order of magnitude and show promise for dielectric wakefield accelerators as sources of high-energy electrons. PMID:27624348

  14. Observation of acceleration and deceleration in gigaelectron-volt-per-metre gradient dielectric wakefield accelerators.

    PubMed

    O'Shea, B D; Andonian, G; Barber, S K; Fitzmorris, K L; Hakimi, S; Harrison, J; Hoang, P D; Hogan, M J; Naranjo, B; Williams, O B; Yakimenko, V; Rosenzweig, J B

    2016-09-14

    There is urgent need to develop new acceleration techniques capable of exceeding gigaelectron-volt-per-metre (GeV m(-1)) gradients in order to enable future generations of both light sources and high-energy physics experiments. To address this need, short wavelength accelerators based on wakefields, where an intense relativistic electron beam radiates the demanded fields directly into the accelerator structure or medium, are currently under intense investigation. One such wakefield based accelerator, the dielectric wakefield accelerator, uses a dielectric lined-waveguide to support a wakefield used for acceleration. Here we show gradients of 1.347±0.020 GeV m(-1) using a dielectric wakefield accelerator of 15 cm length, with sub-millimetre transverse aperture, by measuring changes of the kinetic state of relativistic electron beams. We follow this measurement by demonstrating accelerating gradients of 320±17 MeV m(-1). Both measurements improve on previous measurements by and order of magnitude and show promise for dielectric wakefield accelerators as sources of high-energy electrons.

  15. Observation of acceleration and deceleration in gigaelectron-volt-per-metre gradient dielectric wakefield accelerators

    DOE PAGES

    O’Shea, B. D.; Andonian, G.; Barber, S. K.; ...

    2016-09-14

    There is urgent need to develop new acceleration techniques capable of exceeding gigaelectron-volt-per-metre (GeV m–1) gradients in order to enable future generations of both light sources and high-energy physics experiments. To address this need, short wavelength accelerators based on wakefields, where an intense relativistic electron beam radiates the demanded fields directly into the accelerator structure or medium, are currently under intense investigation. One such wakefield based accelerator, the dielectric wakefield accelerator, uses a dielectric lined-waveguide to support a wakefield used for acceleration. Here we show gradients of 1.347±0.020 GeV m–1 using a dielectric wakefield accelerator of 15 cm length, withmore » sub-millimetre transverse aperture, by measuring changes of the kinetic state of relativistic electron beams. We follow this measurement by demonstrating accelerating gradients of 320±17 MeV m–1. As a result, both measurements improve on previous measurements by and order of magnitude and show promise for dielectric wakefield accelerators as sources of high-energy electrons.« less

  16. Observation of acceleration and deceleration in gigaelectron-volt-per-metre gradient dielectric wakefield accelerators

    SciTech Connect

    O’Shea, B. D.; Andonian, G.; Barber, S. K.; Fitzmorris, K. L.; Hakimi, S.; Harrison, J.; Hoang, P. D.; Hogan, M. J.; Naranjo, B.; Williams, O. B.; Yakimenko, V.; Rosenzweig, J. B.

    2016-09-14

    There is urgent need to develop new acceleration techniques capable of exceeding gigaelectron-volt-per-metre (GeV m–1) gradients in order to enable future generations of both light sources and high-energy physics experiments. To address this need, short wavelength accelerators based on wakefields, where an intense relativistic electron beam radiates the demanded fields directly into the accelerator structure or medium, are currently under intense investigation. One such wakefield based accelerator, the dielectric wakefield accelerator, uses a dielectric lined-waveguide to support a wakefield used for acceleration. Here we show gradients of 1.347±0.020 GeV m–1 using a dielectric wakefield accelerator of 15 cm length, with sub-millimetre transverse aperture, by measuring changes of the kinetic state of relativistic electron beams. We follow this measurement by demonstrating accelerating gradients of 320±17 MeV m–1. As a result, both measurements improve on previous measurements by and order of magnitude and show promise for dielectric wakefield accelerators as sources of high-energy electrons.

  17. The updated billion-ton resource assessment

    SciTech Connect

    Turhollow, Anthony; Perlack, Robert; Eaton, Laurence; Langholtz, Matthew; Brandt, Craig; Downing, Mark; Wright, Lynn; Skog, Kenneth; Hellwinckel, Chad; Stokes, Bryce; Lebow, Patricia

    2014-10-03

    This paper summarizes the results of an update to a resource assessment, published in 2005, commonly referred to as the billion-ton study (BTS). The updated results are consistent with the 2005 BTS in terms of overall magnitude. However, in looking at the major categories of feedstocks the forest residue biomass potential was determined to be less owing to tighter restrictions on forest residue supply including restrictions due to limited projected increase in traditional harvest for pulpwood and sawlogs. The crop residue potential was also determined to be less because of the consideration of soil carbon and not allowing residue removal from conventionally tilled corn acres. The energy crop potential was estimated to be much greater largely because of land availability and modeling of competition among various competing uses of the land. Generally, the scenario assumptions in the updated assessment are much more plausible to show a billion-ton resource, which would be sufficient to displace 30% or more of the country s present petroleum consumption.

  18. The updated billion-ton resource assessment

    DOE PAGES

    Turhollow, Anthony; Perlack, Robert; Eaton, Laurence; ...

    2014-10-03

    This paper summarizes the results of an update to a resource assessment, published in 2005, commonly referred to as the billion-ton study (BTS). The updated results are consistent with the 2005 BTS in terms of overall magnitude. However, in looking at the major categories of feedstocks the forest residue biomass potential was determined to be less owing to tighter restrictions on forest residue supply including restrictions due to limited projected increase in traditional harvest for pulpwood and sawlogs. The crop residue potential was also determined to be less because of the consideration of soil carbon and not allowing residue removalmore » from conventionally tilled corn acres. The energy crop potential was estimated to be much greater largely because of land availability and modeling of competition among various competing uses of the land. Generally, the scenario assumptions in the updated assessment are much more plausible to show a billion-ton resource, which would be sufficient to displace 30% or more of the country s present petroleum consumption.« less

  19. The ExaVolt Antenna: Concept and Development Updates

    NASA Astrophysics Data System (ADS)

    Pfendner, Carl

    2017-03-01

    A flux of ultrahigh energy neutrinos is expected both directly from sources and from interactions between ultrahigh energy cosmic rays and the cosmic microwave background. Using the cost-effective radio Cherenkov technique to search for these neutrinos, the ExaVolt Antenna (EVA) is a mission concept that aims to build on the capabilities of earlier radio-based balloon-borne neutrino detectors and increase the sensitivity to lower energies and fluxes. The novel EVA design exploits the surface of the balloon to provide a focusing reflector that aims to provide a signal gain of 30 dBi (compared to 10 dBi on ANITA). This increase in gain when combined with a large instantaneous viewing angle will yield a 10-fold increase in sensitivity and will allow this balloon-borne experiment to probe the expected low neutrino fluxes even at energies greater than 1019 eV. This contribution will present an overview of the mission concept, recent technology developments, and the results of a hang test of a 1:20-scale model which demonstrates the effectiveness of the design.

  20. Simulating Billion-Task Parallel Programs

    SciTech Connect

    Perumalla, Kalyan S; Park, Alfred J

    2014-01-01

    In simulating large parallel systems, bottom-up approaches exercise detailed hardware models with effects from simplified software models or traces, whereas top-down approaches evaluate the timing and functionality of detailed software models over coarse hardware models. Here, we focus on the top-down approach and significantly advance the scale of the simulated parallel programs. Via the direct execution technique combined with parallel discrete event simulation, we stretch the limits of the top-down approach by simulating message passing interface (MPI) programs with millions of tasks. Using a timing-validated benchmark application, a proof-of-concept scaling level is achieved to over 0.22 billion virtual MPI processes on 216,000 cores of a Cray XT5 supercomputer, representing one of the largest direct execution simulations to date, combined with a multiplexing ratio of 1024 simulated tasks per real task.

  1. 76 FR 19467 - Weyerhaeuser Company, Corporate Headquarters Including On-Site Leased Workers From Volt Services...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-07

    ... Employment and Training Administration Weyerhaeuser Company, Corporate Headquarters Including On-Site Leased... to workers of Weyerhaeuser Company, Corporate Headquarters, including on-site leased workers from Volt Services, Adecco, and Manpower, Federal Way, Washington. The workers supply corporate...

  2. Eight billion asteroids in the Oort cloud

    NASA Astrophysics Data System (ADS)

    Shannon, Andrew; Jackson, Alan P.; Veras, Dimitri; Wyatt, Mark

    2015-01-01

    The Oort cloud is usually thought of as a collection of icy comets inhabiting the outer reaches of the Solar system, but this picture is incomplete. We use simulations of the formation of the Oort cloud to show that ˜4 per cent of the small bodies in the Oort cloud should have formed within 2.5 au of the Sun, and hence be ice-free rock-iron bodies. If we assume that these Oort cloud asteroids have the same size distribution as their cometary counterparts, the Large Synoptic Survey Telescope should find roughly a dozen Oort cloud asteroids during 10 years of operations. Measurement of the asteroid fraction within the Oort cloud can serve as an excellent test of the Solar system's formation and dynamical history. Oort cloud asteroids could be of particular concern as impact hazards as their high mass density, high impact velocity, and low visibility make them both hard to detect and hard to divert or destroy. However, they should be a rare class of object, and we estimate globally catastrophic collisions should only occur about once per billion years.

  3. Uranium in Canada: A billion dollar industry

    SciTech Connect

    Ruzicka, V. )

    1989-12-01

    In 1988, Canada maintained its position as the world's leading producer of uranium with an output of more than 12,400 MT of uranium in concentrates, worth $1.1 billion Canadian. As domestic requirements represent only 15% of current Canadian production, most of the output was exported. With current implementation of the Canada/US Free Trade Agreement, the US has become Canada's major uranium export customer. With a large share of the world's known uranium resources, Canada remains the focus of international uranium exploration activity. In 1988, the uranium exploration expenditures in Canada exceeded $58 million Canadian. The principal exploration targets were deposits associated with Proterozoic unconformities in Saskatchewan and Northwest Territories, particularly those in the Athabasca and Thelon basin regions of the Canadian Shield. Major attention was also paid to polymetallic deposits in which uranium is associated with precious metals, such as gold and platinum group elements. Conceptual genetic models for these deposit types represent useful tools to guide exploration.

  4. Agroecohydrology: Key to Feeding 9 Billion?

    NASA Astrophysics Data System (ADS)

    Herrick, J.

    2011-12-01

    Agricultural production necessary to feed 9 billion people in 2050 depends on increased production on existing croplands, and expanding onto 'marginal' lands. A high proportion of these lands are marginal because they are too steep or too dry to reliably support crop production. These same characteristics increase their susceptibility to accelerated erosion, leading (for most soil profiles) to further reductions in plant available water as infiltration and soil profile water holding capacity decline. Sustaining production on these marginal lands will require careful land use planning. In this paper, we present a land use planning framework that integrates 4 elements: (1) potential production (based on soil profile characteristics), (2) edaphic, topographic and climatic limitations to production, (3) soil resistance to degradation, and (4) resilience. This framework expands existing land capability classification systems through the integration of biophysical feedbacks and thresholds. State and transition models, similar to those currently applied to rangelands in the United States and other countries, are used to organize and communicate knowledge about the sustainability of different land use changes and management actions at field to regional scales. This framework emphasizes hydrologic characteristics of soil profiles and landscapes over fertility because fertility declines are more easily addressed through increased inputs. The presentation will conclude with a discussion of how research in ecohydrology can be more effectively focused to support sustainable food production in the context of increasingly rapid social and economic changes throughout the world.

  5. Observations of the nighttime electron volt range electron fluxes in the equatorial region

    NASA Technical Reports Server (NTRS)

    Rao, B. C. N.; Singh, R.; Maier, E. J.

    1974-01-01

    The importance of some of the features observed among the nighttime equatorial data of Explorer 31 is discussed with respect to the nighttime thermal structure of the topside ionosphere. The very short-lived photoelectrons being absent, the nighttime measurements represent the background flux due to magnetospheric particles.

  6. Sneak Peek to the 2016 Billion-Ton Report

    SciTech Connect

    2016-06-01

    The 2005 Billion-Ton Study became a landmark resource for bioenergy stakeholders, detailing for the first time the potential to produce at least one billion dry tons of biomass annually in a sustainable manner from U.S. agriculture and forest resources. The 2011 U.S. Billion-Ton Update expanded and updated the analysis, and in 2016, the U.S. Department of Energy’s Bioenergy Technologies Office plans to release the 2016 Billion-Ton Report: Advancing Domestic Resources for a Thriving Bioeconomy.

  7. Automation of Coordinated Planning Between Observatories: The Visual Observation Layout Tool (VOLT)

    NASA Technical Reports Server (NTRS)

    Maks, Lori; Koratkar, Anuradha; Kerbel, Uri; Pell, Vince

    2002-01-01

    Fulfilling the promise of the era of great observatories, NASA now has more than three space-based astronomical telescopes operating in different wavebands. This situation provides astronomers with the unique opportunity of simultaneously observing a target in multiple wavebands with these observatories. Currently scheduling multiple observatories simultaneously, for coordinated observations, is highly inefficient. Coordinated observations require painstaking manual collaboration among the observatory staff at each observatory. Because they are time-consuming and expensive to schedule, observatories often limit the number of coordinated observations that can be conducted. In order to exploit new paradigms for observatory operation, the Advanced Architectures and Automation Branch of NASA's Goddard Space Flight Center has developed a tool called the Visual Observation Layout Tool (VOLT). The main objective of VOLT is to provide a visual tool to automate the planning of coordinated observations by multiple astronomical observatories. Four of NASA's space-based astronomical observatories - the Hubble Space Telescope (HST), Far Ultraviolet Spectroscopic Explorer (FUSE), Rossi X-ray Timing Explorer (RXTE) and Chandra - are enthusiastically pursuing the use of VOLT. This paper will focus on the purpose for developing VOLT, as well as the lessons learned during the infusion of VOLT into the planning and scheduling operations of these observatories.

  8. [Effect of the mobility of gate charges on volt-ampere characteristics of excitable membranes].

    PubMed

    Radchenko, A N

    1996-01-01

    An assumption on nature of the gate charges and known data on gate changes mobility allow to deduce the volt-ampere characteristics of ionic channels and the same for membrane. Model research shows that the volt-ampere curve shape depends on gate charges mobility. Its reduction and the followed gate charges immobilization during membrane excitation process are expressed as the changes of volt-ampere curves. These changes might be to specify as the fast components of the inactivation process. A number critical values of the gate charges mobility are calculated which are important for the functions of memory (hysteresis) and excitation (negative resistance). The coincidence of values of biased charge in model and experiment is noted. The formulae that are drown are compared with Hodgkin-Huxley approximations.

  9. Volt-VAR Optimization on American Electric Power Feeders in Northeast Columbus

    SciTech Connect

    Schneider, Kevin P.; Weaver, T. F.

    2012-05-10

    In 2007 American Electric Power launched the gridSMART® initiative with the goals of increasing efficiency of the electricity delivery system and improving service to the end-use customers. As part of the initiative, a coordinated Volt-VAR system was deployed on eleven distribution feeders at five substations in the Northeast Columbus Ohio Area. The goal of the coordinated Volt-VAR system was to decrease the amount of energy necessary to provide end-use customers with the same quality of service. The evaluation of the Volt-VAR system performance was conducted in two stages. The first stage was composed of simulation, analysis, and estimation, while the second stage was composed of analyzing collected field data. This panel paper will examine the analysis conducted in both stages and present the estimated improvements in system efficiency.

  10. Modelling pesticide volatilization after soil application using the mechanistic model Volt'Air

    NASA Astrophysics Data System (ADS)

    Bedos, Carole; Génermont, Sophie; Le Cadre, Edith; Garcia, Lucas; Barriuso, Enrique; Cellier, Pierre

    Volatilization of pesticides participates in atmospheric contamination and affects environmental ecosystems including human welfare. Modelling at relevant time and spatial scales is needed to better understand the complex processes involved in pesticide volatilization. Volt'Air-Pesticides has been developed following a two-step procedure to study pesticide volatilization at the field scale and at a quarter time step. Firstly, Volt'Air-NH 3 was adapted by extending the initial transfer of solutes to pesticides and by adding specific calculations for physico-chemical equilibriums as well as for the degradation of pesticides in soil. Secondly, the model was evaluated in terms of 3 pesticides applied on bare soil (atrazine, alachlor, and trifluralin) which display a wide range of volatilization rates. A sensitivity analysis confirmed the relevance of tuning to K h. Then, using Volt'Air-Pesticides, environmental conditions and emission fluxes of the pesticides were compared to fluxes measured under 2 environmental conditions. The model fairly well described water temporal dynamics, soil surface temperature, and energy budget. Overall, Volt'Air-Pesticides estimates of the order of magnitude of the volatilization flux of all three compounds were in good agreement with the field measurements. The model also satisfactorily simulated the decrease in the volatilization rate of the three pesticides during night-time as well as the decrease in the soil surface residue of trifluralin before and after incorporation. However, the timing of the maximum flux rate during the day was not correctly described, thought to be linked to an increased adsorption under dry soil conditions. Thanks to Volt'Air's capacity to deal with pedo-climatic conditions, several existing parameterizations describing adsorption as a function of soil water content could be tested. However, this point requires further investigation. Practically speaking, Volt'Air-Pesticides can be a useful tool to make

  11. Experimental evaluation of a volts-per-hertz reference circuit for the isotope Brayton system

    NASA Technical Reports Server (NTRS)

    Wimmer, H. L.

    1972-01-01

    In Brayton-cycle power systems, the speed decreases rapidly with overload. If the voltage decreases linearly with speed (frequency), the power decreases as the square of the voltage. This makes the system more tolerant of overloads. A volts-per-hertz reference circuit, consisting of a volts-per-hertz sensor and a voltage limiter, was designed and fabricated. This reference circuit was incorporated in an existing voltage regulator to control a turbine-driven alternator. Test results show that the control does function to reduce voltage at speeds below the rated speed and that it performed successfully during transients.

  12. Performance Evaluation of a 22.5/30 KW 270 Volts Direct Current Generator System

    DTIC Science & Technology

    1993-12-01

    AD-A275 106 WL-TR-93-2025 PERFORMANCE EVALUATION OF A 22.5/30 KW 270 VOLTS DIRECT CURRENT GENERATOR SYSTEM John G. Nairus, David A. Criminski Power...the addressee is no longer employed by your organization please notify WL/POOC , WPAFB, OH 45433- 7251 to help us maintain a current mailing list...30 kW 270 Volts Direct Program Element No. Current Generator System 62203F 6. AUTHOR(S) Work Unit No. 31452939 John G. Nairus, David A. Criminski 7

  13. Actual Versus Estimated Utility Factor of a Large Set of Privately Owned Chevrolet Volts

    SciTech Connect

    John Smart; Thomas Bradley; Stephen Schey

    2014-04-01

    In order to determine the overall fuel economy of a plug-in hybrid electric vehicle (PHEV), the amount of operation in charge depleting (CD) versus charge sustaining modes must be determined. Mode of operation is predominantly dependent on customer usage of the vehicle and is therefore highly variable. The utility factor (UF) concept was developed to quantify the distance a group of vehicles has traveled or may travel in CD mode. SAE J2841 presents a UF calculation method based on data collected from travel surveys of conventional vehicles. UF estimates have been used in a variety of areas, including the calculation of window sticker fuel economy, policy decisions, and vehicle design determination. The EV Project, a plug-in electric vehicle charging infrastructure demonstration being conducted across the United States, provides the opportunity to determine the real-world UF of a large group of privately owned Chevrolet Volt extended range electric vehicles. Using data collected from Volts enrolled in The EV Project, this paper compares the real-world UF of two groups of Chevrolet Volts to estimated UF's based on J2841. The actual observed fleet utility factors (FUF) for the MY2011/2012 and MY2013 Volt groups studied were observed to be 72% and 74%, respectively. Using the EPA CD ranges, the method prescribed by J2841 estimates a FUF of 65% and 68% for the MY2011/2012 and MY2013 Volt groups, respectively. Volt drivers achieved higher percentages of distance traveled in EV mode for two reasons. First, they had fewer long-distance travel days than drivers in the national travel survey referenced by J2841. Second, they charged more frequently than the J2841 assumption of once per day - drivers of Volts in this study averaged over 1.4 charging events per day. Although actual CD range varied widely as driving conditions varied, the average CD ranges for the two Volt groups studied matched the EPA CD range estimates, so CD range variation did not affect FUF results.

  14. Battery Test Manual For 12 Volt Start/Stop Hybrid Electric Vehicles

    SciTech Connect

    Belt, Jeffrey R.

    2015-05-01

    This manual was prepared by and for the United Stated Advanced Battery Consortium (USABC) Electrochemical Energy Storage Team. It is based on the targets established for 12 Volt Start/Stop energy storage development and is similar (with some important changes) to an earlier manual for the former FreedomCAR program. The specific procedures were developed primarily to characterize the performance of energy storage devices relative to the USABC requirements. However, it is anticipated that these procedures will have some utility for characterizing 12 Volt Start/Stop hybrid energy storage device behavior in general.

  15. 75 FR 11920 - Agilent Technologies, Eesof Division, Including On-Site Leased Workers From Volt and Managed...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-12

    ... Technologies, EEsof Division, including on-site leased workers from Volt and Managed Business Solutions (MBS... Employment and Training Administration Agilent Technologies, Eesof Division, Including On-Site Leased Workers From Volt and Managed Business Solutions (MBS), Westlake Village, CA, Santa Rosa, CA, Santa Clara,...

  16. How much are Chevrolet Volts in The EV Project driven in EV Mode?

    SciTech Connect

    John Smart

    2013-08-01

    This report summarizes key conclusions from analysis of data collected from Chevrolet Volts participating in The EV Project. Topics include how many miles are driven in EV mode, how far vehicles are driven between charging events, and how much energy is charged from the electric grid per charging event.

  17. View of 500,000 volt spreading yard that transfers power from ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of 500,000 volt spreading yard that transfers power from underground cable, from Third Powerhouse, to overhead line; the towers are pipe-type transformer towers. Looking west. - Columbia Basin Project, Grand Coulee Dam Powerplant Complex, Grand Coulee, Grant County, WA

  18. 5. Photocopy of photograph, c. 1904. VIEW OF 12,000 VOLT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. Photocopy of photograph, c. 1904. VIEW OF 12,000 VOLT TRANSMISSION LINE BETWEEN THE ORIGINAL POWER HOUSE AT DAM NO. 5 AND MARTINSBURG. (From the collection of Mr. Charles Morrison, Hagerstown, MD) - Dam No. 5 Hydroelectric Plant, On Potomac River, Hedgesville, Berkeley County, WV

  19. 136. View of former high tension (55,000 volt) bus room ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    136. View of former high tension (55,000 volt) bus room on the third floor, looking south. Photo by Jet Lowe, HAER, 1989. - Puget Sound Power & Light Company, White River Hydroelectric Project, 600 North River Avenue, Dieringer, Pierce County, WA

  20. 42. Photocopy of photograph, c. 1930. DETAIL OF 33,000 VOLT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    42. Photocopy of photograph, c. 1930. DETAIL OF 33,000 VOLT HIGH TENSION SUBSTATION AND STEP UP TRANSFORMERS. (From the collection of the files of Mr. Tony Robucci, Supervisor for Minor Stations, Potomac Edison Company, Hagerstown, MD) - Dam No. 5 Hydroelectric Plant, On Potomac River, Hedgesville, Berkeley County, WV

  1. 29. INDUCTION MOTOR (6600 VOLTS, 5750 H.P.) DRIVES THE 21INCH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    29. INDUCTION MOTOR (6600 VOLTS, 5750 H.P.) DRIVES THE 21-INCH AND 18-INCH BILLET MILLS. MOTOR WAS MANUFACTURED BY THE GENERAL ELECTRIC COMPANY, SCHENECTADY, NEW YORK. - Corrigan, McKinney Steel Company, 3100 East Forty-fifth Street, Cleveland, Cuyahoga County, OH

  2. Advanced Vehicle Testing Activity Cold Weather On-road Testing of the Chevrolet Volt

    SciTech Connect

    Smart, John

    2015-03-01

    This report details cold weather on-road testing of a Chevrolet Volt. It quantifies changes in efficiency and electric range as ambient temperature changes. It will be published to INL's AVTA website as an INL technical report and will be accessible to the general public.

  3. How many electric miles do Nissan Leafs and Chevrolet Volts in The EV Project travel?

    SciTech Connect

    John Smart

    2014-05-01

    This paper presents travel statistics and metrics describing the driving behavior of Nissan Leaf and Chevrolet Volt drivers in the EV Project. It specifically quantifies the distance each group of vehicles drives each month. This paper will be published to INL's external website and will be accessible by the general public.

  4. 39. NORTH WALL OF MST AT STATION 124. 480VOLT MASTER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    39. NORTH WALL OF MST AT STATION 124. 480-VOLT MASTER POWER SHUTOFF AND CIRCUIT BREAKERS FOR CRANE NORTH DOORS/CRANE SOUTH DOORS ON LEFT; FOR BRIDGE CRANE AND DUCT HEATER 122 ON RIGHT. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  5. An optimization approach for online identification of harmonic resonance due to pending Volt/VAr operation

    NASA Astrophysics Data System (ADS)

    McBee, Kerry D.

    The emphasis on creating a more efficient distribution system has led many utility companies to employ dynamic voltage and VAr compensation (Volt/VAr) applications that reduce energy demand, generation, and losses associated with the transmission and distribution of energy. To achieve these benefits, Volt/VAr applications rely upon algorithms to control voltage support equipment, such as transformer load tap changers, voltage regulators, and capacitor banks. The majority of these algorithms utilize metaheuristic programming methods to determine the Volt/VAr scheme that produces the most energy efficient operating conditions. It has been well documented that the interaction between capacitor bank reactance and the inductive reactance of a distribution system can produce parallel harmonic resonance that can damage utility and customer equipment. The Volt/VAr controlling algorithms that account for harmonics do so in an indirect manner that can mask harmonic resonance conditions. Unlike previous research endeavors, the primary focus of the method described within this dissertation is to identify Volt/VAr schemes that prevent harmonic resonance due to capacitor bank operation. Instead of a metaheuristic approach, the harmonic resonance identification algorithm relies upon constrained mixed integer nonlinear programming (MINLP), which is more suited for analyzing impedance characteristics created by the energized states of a system of capacitor banks. Utilizing a numerical approach improves the accuracy of identifying harmonic resonance conditions, while also reducing the complexity of the process by exclusively relying upon the system's admittance characteristics. The novel harmonic resonance identification method is applicable to distribution systems that are dynamically reconfigured, which can result in a number of unknown harmonic resonance producing conditions, a feature unavailable with existing controlling algorithms. The ability to identify all harmonic

  6. EPA Survey Shows $271 Billion Needed for Nations Wastewater Infrastructure

    EPA Pesticide Factsheets

    WASHINGTON - The U.S. Environmental Protection Agency (EPA) today released a survey showing that $271 billion is needed to maintain and improve the nation's wastewater infrastructure, including the pipes that carry wastewater to treatment plants, th

  7. Harnessing Energy from the Sun for Six Billion People

    ScienceCinema

    Daniel Nocera

    2016-07-12

    Daniel Nocera, a Massachusetts Institute of Technology professor whose recent research focuses on solar-powered fuels, presents a Brookhaven Science Associates Distinguished Lecture, titled "Harnessing Energy from the Sun for Six Billion People -- One at a Time."

  8. NASA Now Minute: Earth and Space Science: 100 Billion Planets

    NASA Video Gallery

    Stephen Kane, co-author of the article, “Study Shows Our Galaxy has 100Billion Planets” reveals details about this incredible study explainsjust how common planets are in our Milky Way galaxy...

  9. Academic Pork Barrel Tops $2-Billion for the First Time.

    ERIC Educational Resources Information Center

    Brainard, Jeffrey; Borrego, Anne Marie

    2003-01-01

    Describes how, despite the growing budget deficit, Congress directed a record $2 billion to college projects in 2003, many of them dealing with security and bioterrorism. Includes data tables on the earmarks. (EV)

  10. Summary and Comparison of the 2016 Billion-Ton Report with the 2011 U.S. Billion-Ton Update

    SciTech Connect

    2016-06-01

    In terms of the magnitude of the resource potential, the results of the 2016 Billion-Ton Report (BT16) are consistent with the original 2005 Billion-Ton Study (BTS) and the 2011 report, U.S. Billion-Ton Update: Biomass Supply for a Bioenergy and Bioproducts Industry (BT2. An effort was made to reevaluate the potential forestland, agricultural, and waste resources at the roadside, then extend the analysis by adding transportation costs to a biorefinery under specified logistics assumptions to major resource fractions.

  11. White Nail Radio Transmitter: Billion Dollar Savings through Energy Efficiency

    DTIC Science & Technology

    2011-05-10

    energy consumption ashore by 50 percent CNO, Navy Energy Vision, P 10 White Nail Vision Your Cell Phone Cell ...Greenhouse Gas Power 4 1 Energy Navy Use 7.3 Billion kWh White Nail Cell Phone Savings 11 Billion kWh One and a half times!!! Saves the output of four of...Estimated Total Number of transmitters 3,000,000 Estimated total power saved Watt 1,250,000,000 Cell Phone Transmitter Efficiency 1.25 Gigawatts

  12. NREL Collaboration Breaks 1-Volt Barrier in CdTe Solar Technology

    SciTech Connect

    2016-05-01

    NREL scientists have worked with Washington State University and the University of Tennessee to improve the maximum voltage available from CdTe solar cells. Changes in dopants, stoichiometry, interface design, and defect chemistry improved the CdTe conductivity and carrier lifetime by orders of magnitude, thus enabling CdTe solar cells with open-circuit voltages exceeding 1 volt for the first time. Values of current density and fill factor for CdTe solar cells are already at high levels, but sub-par voltages has been a barrier to improved efficiencies. With voltages pushed beyond 1 volt, CdTe cells have a path to produce electricity at costs less than fossil fuels.

  13. Evaluation of Multiple Inverter Volt-VAR Control Interactions with Realistic Grid Impedances

    SciTech Connect

    Chakraborty, Sudipta; Hoke, Anderson; Lundstrom, Blake

    2015-07-03

    Integration of large numbers of distributed photovoltaic (PV) systems in electric distribution circuits often requires advanced functions (e.g. volt-VAR, frequency-Watt etc.). However, significant concerns have been raised about potential for PV inverters with such controls to interact with one another in a way that could cause grid instability. The lack of standardized inverter models makes it hard to simulate such transient interactions in software. Similarly it is very hard to test these dynamic inverter interactions in the laboratory. In this paper, unique Power Hardware-in-the-Loop (PHIL) techniques are presented to experimentally test for interactions of multiple PV inverters connected to multiple points-of-common-coupling (PCCs) with grid impedances between them. Sample test results are provided from simulation-only scenarios and PHIL testing. Though simulation results indicated possible harmful interactions between inverters' volt-VAR controllers; no such interactions were found in the limited hardware testing.

  14. 134. View of former high tension (55,000 volt) bus room ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    134. View of former high tension (55,000 volt) bus room on the third floor, looking north. This room now contains shelves and boxes for storing company records (to the left along the wall). Insulators through which the live line ran remains in place. Photo by Jet Lowe, HAER, 1989. - Puget Sound Power & Light Company, White River Hydroelectric Project, 600 North River Avenue, Dieringer, Pierce County, WA

  15. A 600 VOLT MULTI-STAGE, HIGH REPETITION RATE GAN FET SWITCH

    SciTech Connect

    Frolov, D.; Pfeffer, H.; Saewert, G.

    2016-10-05

    Using recently available GaN FETs, a 600 Volt three- stage, multi-FET switch has been developed having 2 nanosecond rise time driving a 200 Ohm load with the potential of approaching 30 MHz average switching rates. Possible applications include driving particle beam choppers kicking bunch-by-bunch and beam deflectors where the rise time needs to be custom tailored. This paper reports on the engineering issues addressed, the design approach taken and some performance results of this switch.

  16. Low (Sub-1-volt) halfwave voltage polymeric electro-optic modulators achieved by controlling chromophore shape

    PubMed

    Shi; Zhang; Zhang; Bechtel; Dalton; Robinson; Steier

    2000-04-07

    Electro-optic (EO) modulators encode electrical signals onto fiber optic transmissions. High drive voltages limit gain and noise levels. Typical polymeric and lithium niobate modulators operate with halfwave voltages of 5 volts. Sterically modified organic chromophores have been used to reduce the attenuation of electric field poling-induced electro-optic activity caused by strong intermolecular electrostatic interactions. Such modified chromophores, incorporated into polymer hosts, were used to fabricate EO modulators with halfwave voltages of 0.8 volts (at a telecommunications wavelength of 1318 nanometers) and to achieve a halfwave voltage-interaction length product of 2.2 volt-centimeters. Optical push-pull poling and driving were also used to reduce halfwave voltage. This study, together with recent demonstrations of exceptional bandwidths (more than 110 gigahertz) and ease of integration (with very large scale integration semiconductor circuitry and ultra-low-loss passive optical circuitry) demonstrates the potential of polymeric materials for next generation telecommunications, information processing, and radio frequency distribution.

  17. Winglets Save Billions of Dollars in Fuel Costs

    NASA Technical Reports Server (NTRS)

    2010-01-01

    The upturned ends now featured on many airplane wings are saving airlines billions of dollars in fuel costs. Called winglets, the drag-reducing technology was advanced through the research of Langley Research Center engineer Richard Whitcomb and through flight tests conducted at Dryden Flight Research Center. Seattle-based Aviation Partners Boeing -- a partnership between Aviation Partners Inc., of Seattle, and The Boeing Company, of Chicago -- manufactures Blended Winglets, a unique design featured on Boeing aircraft around the world. These winglets have saved more than 2 billion gallons of jet fuel to date, representing a cost savings of more than $4 billion and a reduction of almost 21.5 million tons in carbon dioxide emissions.

  18. X-ray laser resonator for the kilo-electron-volt range

    SciTech Connect

    Chen, Jie; Tomov, Ivan V.; Er, Ali O.; Rentzepis, Peter M.

    2013-04-29

    We have designed, constructed, and tested an x-ray laser resonator operating in the hard x-ray, keV energy region. This ring x-ray laser cavity is formed by four highly oriented pyrolytic graphite crystals. The crystals are set at the Bragg angles that allow for the complete 360 Degree-Sign round trip of the 2.37 A, 5.23 keV L{sub {alpha}} line of neodymium. In addition, we also present experimental data of a similar ring laser resonator that utilizes the Cr K{sub {alpha}}, 5.41 keV, x-ray line to propagate through the four mirrors of the cavity. The specific properties of these x-ray laser resonator mirrors, including reflection losses and cavity arrangement, are presented.

  19. Charge Transfer Between Ground-State Si(3+) and He at Electron-Volt Energies

    NASA Technical Reports Server (NTRS)

    Fang, Z.; Kwong, Victor H. S.

    1997-01-01

    The charge-transfer rate coefficient for the reaction Si(3+)(3s(sup 2)S) + He yields products is measured by means of a combined technique of laser ablation and ion storage. A cylindrical radio-frequency ion trap was used to store Si(3+) ions produced by laser ablation of solid silicon targets. The rate coefficient of the reaction was derived from the decay rate of the ion signal. The measured rate coefficient is 6.27(exp +0.68)(sub -0.52) x 10(exp -10)cu cm/s at T(sub equiv) = 3.9 x 10(exp 3)K. This value is about 30% higher than the Landau-Zener calculation of Butler and Dalgarno and is larger by about a factor of 3 than the recent full quantal calculation of Honvault et al.

  20. Assessing the ability of mechanistic volatilization models to simulate soil surface conditions: a study with the Volt'Air model.

    PubMed

    Garcia, L; Bedos, C; Génermont, S; Braud, I; Cellier, P

    2011-09-01

    Ammonia and pesticide volatilization in the field is a surface phenomenon involving physical and chemical processes that depend on the soil surface temperature and water content. The water transfer, heat transfer and energy budget sub models of volatilization models are adapted from the most commonly accepted formalisms and parameterizations. They are less detailed than the dedicated models describing water and heat transfers and surface status. The aim of this work was to assess the ability of one of the available mechanistic volatilization models, Volt'Air, to accurately describe the pedo-climatic conditions of a soil surface at the required time and space resolution. The assessment involves: (i) a sensitivity analysis, (ii) an evaluation of Volt'Air outputs in the light of outputs from a reference Soil-Vegetation-Atmosphere Transfer model (SiSPAT) and three experimental datasets, and (iii) the study of three tests based on modifications of SiSPAT to establish the potential impact of the simplifying assumptions used in Volt'Air. The analysis confirmed that a 5 mm surface layer was well suited, and that Volt'Air surface temperature correlated well with the experimental measurements as well as with SiSPAT outputs. In terms of liquid water transfers, Volt'Air was overall consistent with SiSPAT, with discrepancies only during major rainfall events and dry weather conditions. The tests enabled us to identify the main source of the discrepancies between Volt'Air and SiSPAT: the lack of gaseous water transfer description in Volt'Air. They also helped to explain why neither Volt'Air nor SiSPAT was able to represent lower values of surface water content: current classical water retention and hydraulic conductivity models are not yet adapted to cases of very dry conditions. Given the outcomes of this study, we discuss to what extent the volatilization models can be improved and the questions they pose for current research in water transfer modeling and parameterization.

  1. Projecting a world of 10.4 billion.

    PubMed

    Yanagishita, M

    1988-01-01

    Summary data are presented from the World Bank's "World Population 1987-88: Short and Long-Term Estimates by Age and Sex with Related Demographic Statistics." The projections do not differ much from those in the World Bank's 1985 projection except for large upward revisions for South Asian and West Asian countries and especially large upward revisions for Kenya, Ethiopia, Burkina Faso, Nigeria, and Egypt. World population is expected to reach 10.4 billion in 2100 and to stabilize at 10 billion around year 2070. Intermediate figures are given for year 2000 (6.2 billion) and year 2050 (9.5 billion). The fifteen most populous countries in 2100 will be (in millions) China (1683), India (1678), Nigeria (529), Pakistan (395), USSR (385), Indonesia (363), Brazil (292), US (279), Ethiopia (204), Mexico (197), Iran (157), Philippines (137), Egypt (132), Japan (124), and Tanzania (123). The world's annual growth rate (currently 1.7%) will decrease to .9% in 2025 and .07% in 2100 due to decreasing birth rates, especially in Africa. Nevertheless, the population of Sub-Saharan Africa will be 5 times its present size. The slowest annual growth will be for Europe, North America, and China; and the highest for Sri Lanka, Pakistan, and Bangladesh.

  2. Bill and Melinda Gates Pledge $1-Billion for Minority Scholarships.

    ERIC Educational Resources Information Center

    Monaghan, Peter; Lederman, Douglas; van der Werf, Martin; Pulley, John

    1999-01-01

    Reports on a $1 billion dollar grant from Bill and Melinda Gates to send 20,000 low-income minority students to college. The Gates Millenium Scholars Program will require students to demonstrate financial need and maintain a 3.0 grade point average in college. A list of the largest private gifts to higher education since 1967 is also provided. (DB)

  3. Colleges' Billion-Dollar Campaigns Feel the Economy's Sting

    ERIC Educational Resources Information Center

    Masterson, Kathryn

    2009-01-01

    The economy's collapse has caught up with the billion-dollar campaign. In the past 12 months, the amount of money raised by a dozen of the colleges engaged in higher education's biggest fund-raising campaigns fell 32 percent from the year before. The decline, which started before the worst of the recession, has forced colleges to postpone…

  4. Skeptics Say Billions for Education Won't Stimulate Economy

    ERIC Educational Resources Information Center

    Field, Kelly

    2009-01-01

    Skeptics question whether infusion of billions of dollars for education in the economic-stimulus bill before Congress would actually give a healthy jolt to the economy. The bill would help thousands of students pay for college and could give colleges money to fix crumbling buildings. Some members of Congress are calling for the removal of…

  5. Four laser companies to exceed $1 billion revenue in 2016

    NASA Astrophysics Data System (ADS)

    Thoss, Andreas F.

    2017-02-01

    It seems very likely that for first time four companies will exceed the revenue of 1 billion in 2016. This comes along with substantial changes in the market for lasers and laser systems. The article analyzes some of the changes and looks at the individual success strategies of the major players in these markets.

  6. Connectivity-Enhanced Route Selection and Adaptive Control for the Chevrolet Volt: Preprint

    SciTech Connect

    Gonder, J.; Wood, E.; Rajagopalan, S.

    2014-09-01

    The National Renewable Energy Laboratory and General Motors evaluated connectivity-enabled efficiency enhancements for the Chevrolet Volt. A high-level model was developed to predict vehicle fuel and electricity consumption based on driving characteristics and vehicle state inputs. These techniques were leveraged to optimize energy efficiency via green routing and intelligent control mode scheduling, which were evaluated using prospective driving routes between tens of thousands of real-world origin/destination pairs. The overall energy savings potential of green routing and intelligent mode scheduling was estimated at 5% and 3% respectively. These represent substantial opportunities considering that they only require software adjustments to implement.

  7. Operational benefits from optimal volt/var scheduling in the south-east Australian transmission network

    SciTech Connect

    Bauer, E.; Eichler, R.; Lyons, M.

    1995-12-31

    The Victorian power system supplies the Australian federal state of Victoria (population: 4.5 million; capital city: Melbourne) with electricity. Over the last three years an extensive EMS computer system has been installed at the System Control Centre in Melbourne. It includes among other functions a complete set of Optimal Power Flow (OPF) applications. This paper reports on the results gained during the first year of daily application of the Optimal Volt/Var Scheduling (VVS) function and ends with an outlook on planned future extensions.

  8. 14,000 volt electrical injury to bilateral upper extremities: a case report.

    PubMed

    Lee, J; Sinno, H; Perkins, A; Tahiri, Y; Luc, M

    2011-06-01

    Electrical burns are among the most devastating of burn injuries. High voltage electrical injuries result in extensive deep tissue damage and are associated with multiple complications, long term morbidity, and a high mortality rate. We describe the case of a 47 year-old electric company linesman who suffered a high voltage electrical injury (HVEI) of 14,000 volts to bilateral hands and wrists managed by the Division of Plastic and Reconstructive Surgery at the McGill University Health Center in Montreal, Quebec, Canada. His management included multiple operative procedures, including escharotomies, fasciotomies, serial debridements, and bilateral pedicle groin flaps, and amputation of his left hand.

  9. 14,000 Volt Electrical Injury to Bilateral Upper Extremities: A Case Report

    PubMed Central

    Lee, J.; Sinno, H.; Perkins, A.; Tahiri, Y.; Luc, M.

    2011-01-01

    Electrical burns are among the most devastating of burn injuries. High voltage electrical injuries result in extensive deep tissue damage and are associated with multiple complications, long term morbidity, and a high mortality rate. We describe the case of a 47 year-old electric company linesman who suffered a high voltage electrical injury (HVEI) of 14,000 volts to bilateral hands and wrists managed by the Division of Plastic and Reconstructive Surgery at the McGill University Health Center in Montreal, Quebec, Canada. His management included multiple operative procedures, including escharotomies, fasciotomies, serial debridements, and bilateral pedicle groin flaps, and amputation of his left hand. PMID:22399869

  10. Connectivity-enhanced route selection and adaptive control for the Chevrolet Volt

    DOE PAGES

    Gonder, Jeffrey; Wood, Eric; Rajagopalan, Sai

    2016-01-01

    The National Renewable Energy Laboratory and General Motors evaluated connectivity-enabled efficiency enhancements for the Chevrolet Volt. A high-level model was developed to predict vehicle fuel and electricity consumption based on driving characteristics and vehicle state inputs. These techniques were leveraged to optimize energy efficiency via green routing and intelligent control mode scheduling, which were evaluated using prospective driving routes between tens of thousands of real-world origin/destination pairs. The overall energy savings potential of green routing and intelligent mode scheduling was estimated at 5% and 3%, respectively. Furthermore, these represent substantial opportunities considering that they only require software adjustments to implement.

  11. Conservation of protein structure over four billion years

    PubMed Central

    Ingles-Prieto, Alvaro; Ibarra-Molero, Beatriz; Delgado-Delgado, Asuncion; Perez-Jimenez, Raul; Fernandez, Julio M.; Gaucher, Eric A.; Sanchez-Ruiz, Jose M.; Gavira, Jose A.

    2013-01-01

    SUMMARY Little is known with certainty about the evolution of protein structures in general and the degree of protein structure conservation over planetary time scales in particular. Here we report the X-ray crystal structures of seven laboratory resurrections of Precambrian thioredoxins dating back up to ~4 billion years before present. Despite considerable sequence differences compared with extant enzymes, the ancestral proteins display the canonical thioredoxin fold while only small structural changes have occurred over 4 billion years. This remarkable degree of structure conservation since a time near the last common ancestor of life supports a punctuated-equilibrium model of structure evolution in which the generation of new folds occurs over comparatively short periods of time and is followed by long periods of structural stasis. PMID:23932589

  12. Conservation of protein structure over four billion years.

    PubMed

    Ingles-Prieto, Alvaro; Ibarra-Molero, Beatriz; Delgado-Delgado, Asuncion; Perez-Jimenez, Raul; Fernandez, Julio M; Gaucher, Eric A; Sanchez-Ruiz, Jose M; Gavira, Jose A

    2013-09-03

    Little is known about the evolution of protein structures and the degree of protein structure conservation over planetary time scales. Here, we report the X-ray crystal structures of seven laboratory resurrections of Precambrian thioredoxins dating up to approximately four billion years ago. Despite considerable sequence differences compared with extant enzymes, the ancestral proteins display the canonical thioredoxin fold, whereas only small structural changes have occurred over four billion years. This remarkable degree of structure conservation since a time near the last common ancestor of life supports a punctuated-equilibrium model of structure evolution in which the generation of new folds occurs over comparatively short periods and is followed by long periods of structural stasis.

  13. Ubiquitous Supercritical Wing Design Cuts Billions in Fuel Costs

    NASA Technical Reports Server (NTRS)

    2015-01-01

    A Langley Research Center engineer’s work in the 1960s and ’70s to develop a wing with better performance near the speed of sound resulted in a significant increase in subsonic efficiency. The design was shared with industry. Today, Renton, Washington-based Boeing Commercial Airplanes, as well as most other plane manufacturers, apply it to all their aircraft, saving the airline industry billions of dollars in fuel every year.

  14. Oncology pharma costs to exceed $150 billion by 2020.

    PubMed

    2016-10-01

    Worldwide costs of oncology drugs will rise above $150 billion by 2020, according to a report by the IMS Institute for Healthcare Informatics. Many factors are in play, according to IMS, including the new wave of expensive immunotherapies. Pembrolizumab (Keytruda), priced at $150,000 per year per patient, and nivolumab (Opdivo), priced at $165,000, may be harbingers of the market for cancer immunotherapies.

  15. Emergence of modern continental crust about 3 billion years ago

    NASA Astrophysics Data System (ADS)

    Dhuime, Bruno; Wuestefeld, Andreas; Hawkesworth, Chris J.

    2015-07-01

    The continental crust is the principal record of conditions on the Earth during the past 4.4 billion years. However, how the continental crust formed and evolved through time remains highly controversial. In particular, the composition and thickness of juvenile continental crust are unknown. Here we show that Rb/Sr ratios can be used as a proxy for both the silica content and the thickness of the continental crust. We calculate Rb/Sr ratios of the juvenile crust for over 13,000 samples, with Nd model ages ranging from the Hadean to Phanerozoic. The ratios were calculated based on the evolution of Sr isotopes in the period between the TDM Nd model age and the crystallization of the samples analysed. We find that the juvenile crust had a low silica content and was largely mafic in composition during the first 1.5 billion years of Earth’s evolution, consistent with magmatism on a pre-plate tectonics planet. About 3 billion years ago, the Rb/Sr ratios of the juvenile continental crust increased, indicating that the newly formed crust became more silica-rich and probably thicker. This transition is in turn linked to the onset of plate tectonics and an increase of continental detritus into the oceans.

  16. President Carter signs $227 billion excise tax measure

    SciTech Connect

    Miller, C.J.; McAfee, J.; Dibona, C.J.; Carter, J.

    1980-04-07

    According to President J. Carter, who signed into law a $227 billion excise tax (windfall profits tax) on revenue from decontrolled U.S. crude oil production, the new tax program will provide the U.S. with the incentive and the means to produce and conserve domestic oil and replace more oil with alternative sources of energy. According to C. DiBona (API), the new tax will discourage the increased amount of domestic production required to compensate, by the mid-to-late 1980's, for a 1.7 million bbl/day shortfall, which will have to be made up with imports from foreign producers. According to J. McAfee of Gulf Oil Corp., only a token amount, about $34 billion of the $227 billion which will be raised by the new tax over the next decade, will be devoted to energy development and mass transit. According to C. J. Miller of the Independent Petroleum Association of America, the tax's complex and sometimes conflicting regulations will pose harsh problems for smaller producers.

  17. Performance criteria guideline for three explosion protection methods of electrical equipment rated up to 15,000 volts AC

    NASA Technical Reports Server (NTRS)

    Linley, L. J.; Luper, A. B.; Dunn, J. H.

    1982-01-01

    The Bureau of Mines, U.S. Department of the Interior, is reviewing explosion protection methods for use in gassy coal mines. This performance criteria guideline is an evaluation of three explosion protection methods of machines electrically powered with voltages up to 15,000 volts ac. A sufficient amount of basic research has been accomplished to verify that the explosion proof and pressurized enclosure methods can provide adequate explosion protection with the present state of the art up to 15,000 volts ac. This routine application of the potted enclosure as a stand alone protection method requires further investigation or development in order to clarify performance criteria and verification certification requirements. An extensive literature search, a series of high voltage tests, and a design evaluation of the three explosion protection methods indicate that the explosion proof, pressurized, and potted enclosures can all be used to enclose up to 15,000 volts ac.

  18. Scalable in-memory RDFS closure on billions of triples.

    SciTech Connect

    Goodman, Eric L.; Mizell, David

    2010-06-01

    We present an RDFS closure algorithm, specifically designed and implemented on the Cray XMT supercomputer, that obtains inference rates of 13 million inferences per second on the largest system configuration we used. The Cray XMT, with its large global memory (4TB for our experiments), permits the construction of a conceptually straightforward algorithm, fundamentally a series of operations on a shared hash table. Each thread is given a partition of triple data to process, a dedicated copy of the ontology to apply to the data, and a reference to the hash table into which it inserts inferred triples. The global nature of the hash table allows the algorithm to avoid a common obstacle for distributed memory machines: the creation of duplicate triples. On LUBM data sets ranging between 1.3 billion and 5.3 billion triples, we obtain nearly linear speedup except for two portions: file I/O, which can be ameliorated with the additional service nodes, and data structure initialization, which requires nearly constant time for runs involving 32 processors or more.

  19. Extensive facial damage caused by a blast injury arising from a 6 volt lead accumulator.

    PubMed

    Singh, S K; Jain, P; Sinha, J K

    1999-03-01

    Low-voltage electrical injuries are relatively uncommon. Injury caused by flow of heavy current due to short-circuiting a low-voltage battery has not been described in the English literature. A 9-year-old boy connected two thin household electrical wires to the two terminals of a 6 volt (lead accumulator) battery and pressed the other two ends between his teeth. This resulted in a blast causing a compound comminuted fracture of the mandible and extensive tissue damage in the oral cavity. The low internal resistance of a lead accumulator (approximately 0.03 ohms) permits the flow of a heavy current (approximately 200 amps) when short-circuited. This instantaneously vaporises a minuscule portion of wire at approximately 2000 K resulting in a sudden rise of intraoral pressure to 30 kg cm-2 leading to tissue damage.

  20. 2011 Chevrolet Volt VIN 0815 Plug-In Hybrid Electric Vehicle Battery Test Results

    SciTech Connect

    Tyler Gray; Matthew Shirk; Jeffrey Wishart

    2013-07-01

    The U.S. Department of Energy (DOE) Advanced Vehicle Testing Activity (AVTA) program consists of vehicle, battery, and infrastructure testing on advanced technology related to transportation. The activity includes tests on plug-in hybrid electric vehicles (PHEVs), including testing the PHEV batteries when both the vehicles and batteries are new and at the conclusion of 12,000 miles of on-road fleet testing. This report documents battery testing performed for the 2011 Chevrolet Volt PHEV (VIN 1G1RD6E48BU100815). The battery testing was performed by the Electric Transportation Engineering Corporation (eTec) dba ECOtality North America. The Idaho National Laboratory and ECOtality North America collaborate on the AVTA for the Vehicle Technologies Program of the DOE.

  1. A Volt Second Source for Calibration of Integrator in a Pulsed Field Magnetometer

    NASA Astrophysics Data System (ADS)

    Lin, An-Li; He, Jian; Zhang, Yue; John, Dudding; Michael, Hall

    2007-11-01

    A volt-second (Vs) source intended for absolutely calibrating the integrator in a pulsed field magnetometer (PFM) is designed and proven to be with accurate rising and falling edges and reasonable lower uncertainty. A comparison experiment shows that the difference between the magnetic fluxes generated respectively by the Vs source and the mutual inductor is within ±0.04%. The PFM is then calibrated in an absolute way of the Vs source. The calibrated PFM gives the measured results in good agreement with a static BH tracer supplied by National Institute of Metrology of China and provides a convenient way of studying the effect of mathematic process on the dynamic measuring curve of PFMs.

  2. Laboratory testing of chloride 3ET205 6 volt traction battery

    SciTech Connect

    Hardin, J.E.

    1989-10-01

    The purpose of this report is to describe the testing performed on the Chloride 3ET205 6 volt traction batery by the INEL Battery Laboratory, to present the results and conclusions of this testing, and to make appropriate recommendations. The Chloride 3ET205 is a tubular plate lead-acid battery made in England by the Chloride Battery Company and imported into the US. The traction battery division of Chloride has been sold, although Chloride assured its customers that the 3ET205 would continue to be available for their consumption. The new owners of the factory are Tudor and Fulman of France. The joint venture company name is C. E. Ac. It is our understanding that all orders are to be sent to the factory at Salford Rd., Bolton, Lancashire, England BL5 1DD. 5 refs., 13 figs., 4 tabs.

  3. Electric shock and the human body - or 'Is it amps or volts that kill you, sir?'

    NASA Astrophysics Data System (ADS)

    Brown, Colin

    1986-11-01

    One of the experiences that children seem to find most exciting in the school science laboratory is the hair raising one of being charged up using a van de Graaf generator and receiving small electric shocks. Children are quite rightly concerned about when electricity might hurt them and what its effects are. They are motivated by science directly concerned with the human body, with obvious impact on their lives. This is particularly important for girls, who often seem to find other aspects of electricity amongst the least interesting topics in science. Here is an opportunity for the teacher to build on immediate and genuine curiosity. Pupils are already well aware that mains electricity at 240 V can be lethal, yet the teacher seems strangely happy to expose them here to what he claims is tens of thousands of volts! They ask questions such as 'Is it amps of volts that kill you?' with a genuine desire to try and resolve the paradox. When young pupils see an oscilloscope for the first time, they often immediately associate it with the heart monitor seen on a TV hospital drama. ('He's dead sir!' they say, as you show them the timebase operating in the absence of an input signal). They use a microphone to try and detect an ECG signal without success. The real heart monitor works in a totally different way, and that it is in fact quite closely related to the action of electric shocks. The article is a summary of the reading the author undertook to try and cure his ignorance of the interaction between electricity and the human body, so that he could make something of this spontaneous interest on the part of the pupils. It also provides background material for A-level potential medical students, who often study physics without seeing its direct relevance to medicine.

  4. What Kind of Charging Infrastructure Do Chevrolet Volt Drivers in The EV Project Use and When Do They Use It?

    SciTech Connect

    Salisbury, Shawn

    2014-09-01

    This document will present information describing the charging behavior of Chevrolet Volts that were enrolled in the EV Project. It will included aggregated data from more than 1,800 vehicles regarding locations, power levels, and time-of-day of charging events performed by those vehicles. This document will be published to the INL AVTA website.

  5. 75 FR 65515 - NRC Corporation, USPS Help Desk of Customer Care Center, Including On-Site Leased Workers of Volt...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-25

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF LABOR Employment and Training Administration NRC Corporation, USPS Help Desk of Customer Care Center, Including On-Site Leased Workers of Volt Consulting, West Columbia, SC; Notice of Affirmative...

  6. 75 FR 21353 - Intel Corporation, Fab 20 Division, Including On-Site Leased Workers From Volt Technical...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-23

    ... From Volt Technical Resources, Staff Finders Technical, Kelly Services, Retronix International... Services, Hillsboro, Oregon. The notice will be published soon in the Federal Register. At the request of... the Hillsboro, Oregon location of Intel Corporation, Fab 20 Division. The Department has...

  7. Well servicing boom pushes costs over $3 billion

    SciTech Connect

    Not Available

    1981-07-01

    Results of the Annual Petroleum Engineer Well Servicing Survey are presented. The most significant change in well servicing trends was reduced abandonments - the number of abandoned wells dropped from 9011 in 1979 to 3021 in 1980. For the second year in a row, producers will spend more than $3 billion for well services. Well servicing operators performed nearly 568,000 servicing and repair jobs on 734,728 operating wells in the US during 1980. In addition, 71,000 wells were completed or recompleted in 1980. Tables of data are summarized for completion, workover, and servicing activities and for servicing operations for 11 individual US regions, including Appalachia, California on shore/off shore, Four Corners, Great Lakes, Gulf of Mexico, Louisiana (on shore), mid-continent, Rocky-Williston, Texas (on shore, includes SE New Mexico), and the southeast. The US total data exclude wells in Alaska.

  8. Ultrarelativistic heavy ion collisions: the first billion seconds

    NASA Astrophysics Data System (ADS)

    Baym, Gordon

    2016-12-01

    I first review the early history of the ultrarelativistic heavy ion program, starting with the 1974 Bear Mountain Workshop, and the 1983 Aurora meeting of the U.S. Nuclear Science Committtee, just one billion seconds ago, which laid out the initial science goals of an ultrarelativistic collider. The primary goal, to discover the properties of nuclear matter at the highest energy densities, included finding new states of matter - the quark-gluon plasma primarily - and to use collisions to open a new window on related problems of matter in cosmology, neutron stars, supernovae, and elsewhere. To bring out how the study of heavy ions and hot, dense matter in QCD has been fulfilling these goals, I concentrate on a few topics, the phase diagram of matter in QCD, and connections of heavy ion physics to cold atoms, cosmology, and neutron stars.

  9. Fast scalable visualization techniques for interactive billion-particle walkthrough

    NASA Astrophysics Data System (ADS)

    Liu, Xinlian

    This research develops a comprehensive framework for interactive walkthrough involving one billion particles in an immersive virtual environment to enable interrogative visualization of large atomistic simulation data. As a mixture of scientific and engineering approaches, the framework is based on four key techniques: adaptive data compression based on space-filling curves, octree-based visibility and occlusion culling, predictive caching based on machine learning, and scalable data reduction based on parallel and distributed processing. In terms of parallel rendering, this system combines functional parallelism, data parallelism, and temporal parallelism to improve interactivity. The visualization framework will be applicable not only to material simulation, but also to computational biology, applied mathematics, mechanical engineering, and nanotechnology, etc.

  10. Bigger, Better Catalog Unveils Half a Billion Celestial Objects

    NASA Technical Reports Server (NTRS)

    2002-01-01

    These frames are samples from the photographic sky surveys, which have been digitized by a technical team at the Space Telescope Science Institute to support the Hubble Space Telescope operations. The team processed these images to create a new astronomical catalog, called the Guide Star Catalog II. This project was undertaken by the Space Telescope Science Institute as an upgrade to an earlier sky survey and catalog (DSS-I and GSC-I), initially done to provide guide stars for pointing the Hubble Space Telescope. By virtue of its sheer size, the DSS-II and GSC-II have many research applications for both professional and amateur astronomers. [Top] An example from the DSS-II shows the Rosette Nebula, (originally photographed by the Palomar Observatory) as digitized in the DSS-I (left) and DSS-II (right). The DSS-II includes views of the sky at both red and blue wavelengths, providing invaluable color information on about one billion deep-sky objects. [Bottom] This blow-up of the inset box in the raw DSS-I scan shows examples of the GSC-I and the improved GSC-II catalogs. Astronomers extracted the stars from the scanned plate of the Rosette and listed them in the catalogs. The new GSC-II catalog provides the colors, positions, and luminosities of nearly half a billion stars -- over 20 times as many as the original GSC-I. The GSC-II contains information on stars as dim as the 19th magnitude. Credit: NASA, the DSS-II and GSC-II Consortia (with images from the Palomar Observatory-STScI Digital Sky Survey of the northern sky, based on scans of the Second Palomar Sky Survey are copyright c 1993-1999 by the California Institute of Technology)

  11. $75 Billion in Formula Grants Failed to Drive Reform. Can $5 Billion in Competitive Grants Do the Job? Education Stimulus Watch. Special Report 2

    ERIC Educational Resources Information Center

    Smarick, Andy

    2009-01-01

    In early 2009, Congress passed and President Barack Obama signed into law the American Recovery and Reinvestment Act (ARRA), the federal government's nearly $800 billion stimulus legislation. According to key members of Congress and the Obama administration, the education portions of the law, totaling about $100 billion, were designed both to…

  12. Orbital forcing of climate 1.4 billion years ago.

    PubMed

    Zhang, Shuichang; Wang, Xiaomei; Hammarlund, Emma U; Wang, Huajian; Costa, M Mafalda; Bjerrum, Christian J; Connelly, James N; Zhang, Baomin; Bian, Lizeng; Canfield, Donald E

    2015-03-24

    Fluctuating climate is a hallmark of Earth. As one transcends deep into Earth time, however, both the evidence for and the causes of climate change become difficult to establish. We report geochemical and sedimentological evidence for repeated, short-term climate fluctuations from the exceptionally well-preserved ∼1.4-billion-year-old Xiamaling Formation of the North China Craton. We observe two patterns of climate fluctuations: On long time scales, over what amounts to tens of millions of years, sediments of the Xiamaling Formation record changes in geochemistry consistent with long-term changes in the location of the Xiamaling relative to the position of the Intertropical Convergence Zone. On shorter time scales, and within a precisely calibrated stratigraphic framework, cyclicity in sediment geochemical dynamics is consistent with orbital control. In particular, sediment geochemical fluctuations reflect what appear to be orbitally forced changes in wind patterns and ocean circulation as they influenced rates of organic carbon flux, trace metal accumulation, and the source of detrital particles to the sediment.

  13. Nine Billion Years: Past and Future of the Solar System

    NASA Astrophysics Data System (ADS)

    Leubner, I. H.

    2013-05-01

    As the Sun is losing mass and thus gravity by radiation and solar wind, solar-planetary energy balances diminish. Since the planets are only weakly bound to the Sun, the planets have been moving away from the Sun, causing increases of orbits and orbital periods. This is modeled for selected planets from Mercury to Sedna and from the formation of the Solar system at -4.5 to +4.5 billion years (Byr/Ma). Planets were initially significantly closer to the Sun, suggesting that modeling of the formation of the solar system needs to be revisited. By +4.5Byr planets beyond Saturn will have separated from the Solar System. The presently outermost solar object, Sedna, is in the process of separation. Climate changes of Mars and Earth are modeled as a function of time. The prediction of the transition of Mars from water to ice at -3.6 Byr is in agreement with observations (-2.9 to -3.7 Byr). This provides for the first time answers to the why and when of water to ice transition on Mars. Earth temperatures are predicted to decrease by of 38, 24, and 20C between -4.5 Byr to +4.5 Byr for present temperatures of +50, 0, and -50 C, respectively. Mars: Water - Ice Transition

  14. Fuel efficient stoves for the poorest two billion

    NASA Astrophysics Data System (ADS)

    Gadgil, Ashok

    2012-03-01

    About 2 billion people cook their daily meals on generally inefficient, polluting, biomass cookstoves. The fuels include twigs and leaves, agricultural waste, animal dung, firewood, and charcoal. Exposure to resulting smoke leads to acute respiratory illness, and cancers, particularly among women cooks, and their infant children near them. Resulting annual mortality estimate is almost 2 million deaths, higher than that from malaria or tuberculosis. There is a large diversity of cooking methods (baking, boiling, long simmers, brazing and roasting), and a diversity of pot shapes and sizes in which the cooking is undertaken. Fuel-efficiency and emissions depend on the tending of the fire (and thermal power), type of fuel, stove characteristics, and fit of the pot to the stove. Thus, no one perfect fuel-efficient low-emitting stove can suit all users. Affordability imposes a further severe constraint on the stove design. For various economic strata within the users, a variety of stove designs may be appropriate and affordable. In some regions, biomass is harvested non-renewably for cooking fuel. There is also increasing evidence that black carbon emitted from stoves is a significant contributor to atmospheric forcing. Thus improved biomass stoves can also help mitigate global climate change. The speaker will describe specific work undertaken to design, develop, test, and disseminate affordable fuel-efficient stoves for internally displaced persons (IDPs) of Darfur, Sudan, where the IDPs face hardship, humiliation, hunger, and risk of sexual assault owing to their dependence on local biomass for cooking their meals.

  15. Orbital forcing of climate 1.4 billion years ago

    PubMed Central

    Zhang, Shuichang; Wang, Xiaomei; Hammarlund, Emma U.; Wang, Huajian; Costa, M. Mafalda; Bjerrum, Christian J.; Connelly, James N.; Zhang, Baomin; Bian, Lizeng; Canfield, Donald E.

    2015-01-01

    Fluctuating climate is a hallmark of Earth. As one transcends deep into Earth time, however, both the evidence for and the causes of climate change become difficult to establish. We report geochemical and sedimentological evidence for repeated, short-term climate fluctuations from the exceptionally well-preserved ∼1.4-billion-year-old Xiamaling Formation of the North China Craton. We observe two patterns of climate fluctuations: On long time scales, over what amounts to tens of millions of years, sediments of the Xiamaling Formation record changes in geochemistry consistent with long-term changes in the location of the Xiamaling relative to the position of the Intertropical Convergence Zone. On shorter time scales, and within a precisely calibrated stratigraphic framework, cyclicity in sediment geochemical dynamics is consistent with orbital control. In particular, sediment geochemical fluctuations reflect what appear to be orbitally forced changes in wind patterns and ocean circulation as they influenced rates of organic carbon flux, trace metal accumulation, and the source of detrital particles to the sediment. PMID:25775605

  16. ZnO Nanowire-Based Corona Discharge Devices Operated Under Hundreds of Volts

    NASA Astrophysics Data System (ADS)

    Yang, Wenming; Zhu, Rong; Zong, Xianli

    2016-02-01

    Minimizing the voltage of corona discharges, especially when using nanomaterials, has been of great interest in the past decade or so. In this paper, we report a new corona discharge device by using ZnO nanowires operated in atmospheric air to realize continuous corona discharge excited by hundreds of volts. ZnO nanowires were synthesized on microelectrodes using electric-field-assisted wet chemical method, and a thin tungsten film was deposited on the microchip to enhance discharging performance. The testing results showed that the corona inception voltages were minimized greatly by using nanowires compared to conventional dischargers as a result of the local field enhancement of nanowires. The corona could be continuously generated and self-sustaining. It was proved that the law of corona inception voltage obeyed the conventional Peek's breakdown criterion. An optimal thickness of tungsten film coated over ZnO nanowires was figured out to obtain the lowest corona inception voltage. The ion concentration of the nanowire-based discharger attained 1017/m3 orders of magnitude, which is practicable for most discharging applications.

  17. ZnO Nanowire-Based Corona Discharge Devices Operated Under Hundreds of Volts.

    PubMed

    Yang, Wenming; Zhu, Rong; Zong, Xianli

    2016-12-01

    Minimizing the voltage of corona discharges, especially when using nanomaterials, has been of great interest in the past decade or so. In this paper, we report a new corona discharge device by using ZnO nanowires operated in atmospheric air to realize continuous corona discharge excited by hundreds of volts. ZnO nanowires were synthesized on microelectrodes using electric-field-assisted wet chemical method, and a thin tungsten film was deposited on the microchip to enhance discharging performance. The testing results showed that the corona inception voltages were minimized greatly by using nanowires compared to conventional dischargers as a result of the local field enhancement of nanowires. The corona could be continuously generated and self-sustaining. It was proved that the law of corona inception voltage obeyed the conventional Peek's breakdown criterion. An optimal thickness of tungsten film coated over ZnO nanowires was figured out to obtain the lowest corona inception voltage. The ion concentration of the nanowire-based discharger attained 10(17)/m(3) orders of magnitude, which is practicable for most discharging applications.

  18. A remarkable case of rhabdomyolysis associated with ingestion of energy drink 'neon volt'.

    PubMed

    Iyer, Praneet S; Yelisetti, Rishitha; Miriyala, Varun; Siddiqui, Waqas; Kaji, Anand

    2016-01-01

    Rhabdomyolysis is defined as a syndrome characterized by muscle necrosis and the release of intracellular muscle constituents into the circulation. We present a case of a 35-year-old male who exercised for 2 h after ingesting energy drink and subsequently presented with rhabdomyolysis. After excluding common and uncommon causes of rhabdomyolysis, we reached the conclusion that the likely cause was the ingestion of energy drink 'NEON VOLT' in a setting of mild dehydration. Increasing physical activity and intense exercise is becoming a trend in many countries, due to its many health-related benefits such as prevention of obesity. This renewed focus toward optimal fitness has spawned many supplements that aid in improvement of the performance, muscle growth, and recovery. Energy drinks predominantly contain caffeine that is often combined with other supplements to form what manufacturers have termed an 'energy blend'. Studies have shown that excessive caffeine intake from energy drinks can cause arrhythmias, hypertension, dehydration, sleeplessness, nervousness, and in rare instances, rhabdomyolysis. As per Drug Abuse Warning Network report, there is a sharp increase in the number of emergency department visits involving energy drinks from 1,128 visits in 2005 to 16,053 and 13,114 visits in 2008 and 2009, respectively. Due to emergence of energy drink abuse as a national health problem, Food and Drug Administration has launched a dietary supplement adverse event reporting system for surveillance of any adverse events linked to these agents.

  19. 3.5 billion years of reshaped Moho, southern Africa

    NASA Astrophysics Data System (ADS)

    Stankiewicz, Jacek; de Wit, Maarten

    2013-12-01

    According to some previous studies, Archean continental crust is, on global average, apparently thinner than Proterozoic crust. Subsequently, the validity of this statement has been questioned. To provide an additional perspective on this issue, we present analyses of Moho signatures derived from recent seismic data along swaths 2000 km in length across southern Africa and its flanking ocean. The imaged crust has a near continuous age range between ca. 0.1 and 3.7 billion years, and the seismic data allow direct comparison of Moho depths between adjacent Archean, Proterozoic and Phanerozoic crust. We find no simple secular change in depth to Moho over this time period. In contrast, there is significant variation in depth to Moho beneath both Archean and Proterozoic crust; Archean crust of southern Africa displays as much crustal diversity in thickness as the adjacent Proterozoic crust. The Moho beneath all crustal provinces that we have analysed has been severely altered by tectono-metamorphic and igneous processes, in many cases more than once, and cannot provide unequivocal data for geodynamic models dealing with secular changes in continental crust formation. These results and conclusions are similar to those documented along ca. 2000 km swaths across the Canadian Shield recorded by Lithoprobe. Tying the age and character of the Precambrian crust of southern Africa to their depth diversities is clearly related to manifold processes of tectono-thermal ‘surgery’ subsequent to their origin, the details of which are still to be resolved, as they are in most Precambrian terranes. Reconstructing pristine Moho of the early Earth therefore remains a formidable challenge. In South Africa, better knowledge of ‘fossilised’ Archean crustal sections ‘turned-on-edge’, such as at the Vredefort impact crater (for the continental crust), and from the Barberton greenstone belt (for oceanic crust) is needed to characterize potential pristine Archean Moho transitions.

  20. Vizualization Challenges of a Subduction Simulation Using One Billion Markers

    NASA Astrophysics Data System (ADS)

    Rudolph, M. L.; Gerya, T. V.; Yuen, D. A.

    2004-12-01

    Recent advances in supercomputing technology have permitted us to study the multiscale, multicomponent fluid dynamics of subduction zones at unprecedented resolutions down to about the length of a football field. We have performed numerical simulations using one billion tracers over a grid of about 80 thousand points in two dimensions. These runs have been performed using a thermal-chemical simulation that accounts for hydration and partial melting in the thermal, mechanical, petrological, and rheological domains. From these runs, we have observed several geophysically interesting phenomena including the development of plumes with unmixed mantle composition as well as plumes with mixed mantle/crust components. Unmixed plumes form at depths greater than 100km (5-10 km above the upper interface of subducting slab) and consist of partially molten wet peridotite. Mixed plumes form at lesser depth directly from the subducting slab and contain partially molten hydrated oceanic crust and sediments. These high resolution simulations have also spurred the development of new visualization methods. We have created a new web-based interface to data from our subduction simulation and other high-resolution 2D data that uses an hierarchical data format to achieve response times of less than one second when accessing data files on the order of 3GB. This interface, WEB-IS4, uses a Javascript and HTML frontend coupled with a C and PHP backend and allows the user to perform region of interest zooming, real-time colormap selection, and can return relevant statistics relating to the data in the region of interest.

  1. Milk production, water consumption, and somatic cell count responses of cows subject to one to two volts of alternating current.

    PubMed

    Southwick, L H; Wilson, D J; Sears, P M

    1992-08-01

    A dairy farm located in central New York was visited because of complaints of electrical shock in the farmhouse shower and the milk house sink. As much as 2 volts AC of potential difference was measured between the waterline and the cow platform (cow-contact voltage). Voltage was coming from the primary neutral wire. The farm's electrical service was modified so that the farmstead could be connected or disconnected from the primary neutral wire at 2-week intervals for 12 weeks. When connected to the primary neutral wire, voltage between waterline and floor ranged between 0 and 1.8 volts, producing estimated current flow through cows of 3.6 to 4.9 mA; when disconnected from primary neutral wire, voltage between waterline and floor was less than 0.1 volt. There was no difference in mean milk production, bulk tank milk somatic cell count, or water consumption among periods when cows were exposed or unexposed to voltage. Despite statistical nonsignificance, the values for somatic cell count were lower and water consumption was higher when cows were exposed to voltage than when they were not.

  2. Searching for Organics Preserved in 4.5 Billion Year Old Salt

    NASA Technical Reports Server (NTRS)

    Zolensky, Michael E.; Fries, M.; Steele, A.; Bodnar, R.

    2012-01-01

    Our understanding of early solar system fluids took a dramatic turn a decade ago with the discovery of fluid inclusion-bearing halite (NaCl) crystals in the matrix of two freshly fallen brecciated H chondrite falls, Monahans and Zag. Both meteorites are regolith breccias, and contain xenolithic halite (and minor admixed sylvite -- KCl, crystals in their regolith lithologies. The halites are purple to dark blue, due to the presence of color centers (electrons in anion vacancies) which slowly accumulated as 40K (in sylvite) decayed over billions of years. The halites were dated by K-Ar, Rb-Sr and I-Xe systematics to be 4.5 billion years old. The "blue" halites were a fantastic discovery for the following reasons: (1) Halite+sylvite can be dated (K is in sylvite and will substitute for Na in halite, Rb substitutes in halite for Na, and I substitutes for Cl). (2) The blue color is lost if the halite dissolves on Earth and reprecipitates (because the newly-formed halite has no color centers), so the color serves as a "freshness" or pristinity indicator. (3) Halite frequently contains aqueous fluid inclusions. (4) Halite contains no structural oxygen, carbon or hydrogen, making them ideal materials to measure these isotopic systems in any fluid inclusions. (5) It is possible to directly measure fluid inclusion formation temperatures, and thus directly measure the temperature of the mineralizing aqueous fluid. In addition to these two ordinary chondrites halite grains have been reliably reported in several ureilites, an additional ordinary chondrite (Jilin), and in the carbonaceous chondrite (Murchison), although these reports were unfortunately not taken seriously. We have lately found additional fluid inclusions in carbonates in several additional carbonaceous chondrites. Meteoritic aqueous fluid inclusions are apparently relatively widespread in meteorites, though very small and thus difficult to analyze.

  3. Development of an Enhanced GenVARR™ (Generator Volt Ampere Reactive Reserve) System

    SciTech Connect

    Schatz, Joe E.

    2009-03-12

    Transmission system operators require near real time knowledge of reactive power capability to reliably operate large electric power transmission systems. Reactive power produced by, or capable of being produced by, a power generator is often estimated based on a series of mega volt amperes (MVA) capability curves for the generator. These curves indicate the ability of the generator to produce real and reactive power under a variety of conditions. In transmission planning and operating studies, it is often assumed, based on estimates for these capability curves, that the generator can provide its rated MVA capability output when needed for system stability However, generators may not always operate at levels depicted by the maximum MVA capability curve due to present constraints. Transmission system operators utilizing the generators’ capability curves for operation decisions regarding transmission system stability or for planning horizons may overestimate the capability of the generators to supply reactive power when required. Southern Company has enhanced GenVARR(TM), the system of plant data query, retrieval, and analysis and calculates the actual – not estimated -- remaining reactive power output capability. The remaining reactive output is considered spinning reserve and is displayed graphically to transmission control center and generating plant operators to identify real time VAR limits. GenVARR is capable of aggregating generators from a defined region, or other user selectable combinations, to represent the available reserves that the operators are specifically interested in. GenVARR(TM) has been put into live production operation and is expected to significantly improve the overall visibility of the reactive reserve capability of the system. This new version of GenVARR(TM) significantly enhances the products structure and performance, and enables links to other key transmission system operation tools.

  4. Design and fabrication of six-volt vertically-stacked GaAs photovoltaic power converter.

    PubMed

    Zhao, Yongming; Sun, Yurun; He, Yang; Yu, Shuzhen; Dong, Jianrong

    2016-11-30

    A six-volt vertically-stacked, high current GaAs photovoltaic power converter (PPC) has been designed and fabricated to produce output power over 1 W under monochromatic illumination. An N(++)-GaAs/P(++)-AlGaAs tunnel junctions (TJs) structure has been used for connecting each sub-cell in this vertically-stacked PPC device. The thickness of the each GaAs sub-cell has been derived based on the calculation of absorption depth of photons with a wavelength of 808 nm using absorption coefficient obtained from ellipsometry measurements. The devices were characterized under non-uniform CW laser illumination at 808 nm with incident power up to 4.1 W. A maximum conversion efficiency of 50.2% was achieved at 0.3 W under non-uniform (coupled in optical fiber) monochromatic illumination, dropping to 42.5% at 4.1 W. The operating voltage at the maximum power point is 5.5-6.0 V, depending on the incident laser power, and an output electrical power output of 1.3 W can be extracted at a laser power of 2.9 W and the maximum electrical power output amounts to 1.72 W. The external quantum efficiency (EQE) measurement indicates that the performance of PPC can be further improved by refining the design of the thickness of sub-cells and improving TJs.

  5. Effects of sensory-level high-volt pulsed electrical current ondelayed-onset muscle soreness.

    PubMed

    Tourville, Timothy W; Connolly, Declan A J; Reed, Brian V

    2006-09-01

    Ten healthy males and ten healthy females aged 21.5 +/- 3.2 years (mean +/- s) participated in the study, which was designed to evaluate the effectiveness of sensory level-high volt pulsed electrical current (HVPC) on delayed-onset muscle soreness (DOMS). Arm discomfort, elbow extension range of motion and isometric elbow flexion strength were obtained as baseline measurements. Delayed-onset muscle soreness was induced in the participants' dominant or non-dominant arm using two sets of 20 maximal eccentric elbow flexion contractions. After the induction of DOMS, the participants were randomly divided into an experimental condition (HVPC) or a placebo condition. The experimental condition consisted of 20 min of HVPC immediately after the induction of DOMS, and 20 min every 24 h for three consecutive days thereafter. The participants in the placebo condition received an intervention similar in design; however, no electrical current was administered. Baseline measurements were reevaluated at 24, 48, 72 and 96 h after the induction of DOMS. Three weeks later, the participants returned and the protocol was repeated on the contralateral limb, using the opposite intervention (HVPC or placebo). Repeated-measures analysis of variance revealed a significant increase in overall arm discomfort, decrease in elbow extension and decrease in isometric strength for both conditions over time. No significant main effect of treatment, or time-by-treatment interaction, was found for the HVPC condition when compared with the placebo condition for any variable. Sensory-level HVPC, as utilized in our application, was ineffective in reducing the measured variables associated with DOMS.

  6. Design and fabrication of six-volt vertically-stacked GaAs photovoltaic power converter

    PubMed Central

    Zhao, Yongming; Sun, Yurun; He, Yang; Yu, Shuzhen; Dong, Jianrong

    2016-01-01

    A six-volt vertically-stacked, high current GaAs photovoltaic power converter (PPC) has been designed and fabricated to produce output power over 1 W under monochromatic illumination. An N++-GaAs/P++-AlGaAs tunnel junctions (TJs) structure has been used for connecting each sub-cell in this vertically-stacked PPC device. The thickness of the each GaAs sub-cell has been derived based on the calculation of absorption depth of photons with a wavelength of 808 nm using absorption coefficient obtained from ellipsometry measurements. The devices were characterized under non-uniform CW laser illumination at 808 nm with incident power up to 4.1 W. A maximum conversion efficiency of 50.2% was achieved at 0.3 W under non-uniform (coupled in optical fiber) monochromatic illumination, dropping to 42.5% at 4.1 W. The operating voltage at the maximum power point is 5.5–6.0 V, depending on the incident laser power, and an output electrical power output of 1.3 W can be extracted at a laser power of 2.9 W and the maximum electrical power output amounts to 1.72 W. The external quantum efficiency (EQE) measurement indicates that the performance of PPC can be further improved by refining the design of the thickness of sub-cells and improving TJs. PMID:27901079

  7. Design and fabrication of six-volt vertically-stacked GaAs photovoltaic power converter

    NASA Astrophysics Data System (ADS)

    Zhao, Yongming; Sun, Yurun; He, Yang; Yu, Shuzhen; Dong, Jianrong

    2016-11-01

    A six-volt vertically-stacked, high current GaAs photovoltaic power converter (PPC) has been designed and fabricated to produce output power over 1 W under monochromatic illumination. An N++-GaAs/P++-AlGaAs tunnel junctions (TJs) structure has been used for connecting each sub-cell in this vertically-stacked PPC device. The thickness of the each GaAs sub-cell has been derived based on the calculation of absorption depth of photons with a wavelength of 808 nm using absorption coefficient obtained from ellipsometry measurements. The devices were characterized under non-uniform CW laser illumination at 808 nm with incident power up to 4.1 W. A maximum conversion efficiency of 50.2% was achieved at 0.3 W under non-uniform (coupled in optical fiber) monochromatic illumination, dropping to 42.5% at 4.1 W. The operating voltage at the maximum power point is 5.5–6.0 V, depending on the incident laser power, and an output electrical power output of 1.3 W can be extracted at a laser power of 2.9 W and the maximum electrical power output amounts to 1.72 W. The external quantum efficiency (EQE) measurement indicates that the performance of PPC can be further improved by refining the design of the thickness of sub-cells and improving TJs.

  8. The Effects of High-Volt Pulsed Current Electrical Stimulation on Delayed-Onset Muscle Soreness

    PubMed Central

    Butterfield, David Lynn; Draper, David O.; Ricard, Mark D.; Myrer, J. William; Schulthies, Shane S.; Durrant, Earlene

    1997-01-01

    Objective: We investigated three 30-minute high-volt pulsed current electrical stimulation (HVPC) treatments of 125 pps to reduce pain, restore range of motion (ROM), and recover strength loss associated with delayed-onset muscle soreness (DOMS). Design and Setting: Randomized, masked comparison of three 30-minute treatment and sham HVPC regimens over a 48-hour period. Subjects: Twenty-eight college students. Measurements: Subjects performed concentric and eccentric knee extensions with the right leg to induce muscle soreness. Assessments were made before and after the exercise bout and each treatment at 24, 48, and 72 hours postexercise. Results: Three separate 2 × 3 × 2 ANOVAs were used to determine significant differences (p < .05) between days, treatments, and pre-post treatment effects and significant interaction among these variables. Scheffe post hoc tests showed no significant reduction in pain perception or improvement in loss of function at 24, 48, and 72 hours postexercise. Mean pain perception assessments (0 = no pain, 10 = severe pain) for the HVPC group were 2.9, 4.5, and 3.5 and for the sham group 3.8, 4.8, and 3.5). Mean ROM losses for the HVPC group were 9.0°, 22.3°, and 26.2°, and for the sham group were 9.5°, 23.1°, and 23.0°. Mean strength losses (1RM) for the HVPC group were 25.9, 25.7, and 20.8 lbs and for the sham group were 22.3, 22.3, and 13.8 lbs. Conclusions: HVPC as we studied it was ineffective in providing lasting pain reduction and at reducing ROM and strength losses associated with DOMS. PMID:16558426

  9. Optimization of Solar Cell Design for Use with GreenVolts CPV System: Cooperative Research and Development Final Report, CRADA Number CRD-08-00281

    SciTech Connect

    Ward, S.

    2011-05-01

    GreenVolts, a Bay area start-up, was developing a CPV system that was based on a unique reflective optical design. They were interested in adapting the inverted GaInP/GaAs/GaInAs cell structure designed at NREL for use in their system. The purpose of this project was to optimize the inverted GaInP/GaAs/GaInAs cell for operation in the GreenVolts optical system.

  10. Electronic timer for sounding rocket payload use

    NASA Technical Reports Server (NTRS)

    Williams, C. P.

    1986-01-01

    An electronic timer has been developed for sounding rocket use. The timer uses CMOS technology for low power consumption and has a battery back-up to keep the timing circuit active in case of a dropout on the payload power bus. Time-event decoding is done by programming EPROM's which enable a +28 volt dc sourcing output. There are 32 discrete outputs which can provide +28 volt dc into a minimum load impedance of 150 ohms. Inputs are designed to operate on standard CMOS voltage levels, but they can withstand +28 volts dc without damage. The timer can be started by either 'G' or lift-off switch closure or umbilical release at lift-off.

  11. A SWIRE Picture is Worth Billions of Years

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Figure 1: SWIRE View of Distant Galaxies [figure removed for brevity, see original site] [figure removed for brevity, see original site] [figure removed for brevity, see original site] Figure 2Figure 3 Figure 4

    These spectacular images, taken by the Spitzer Wide-area Infrared Extragalactic (SWIRE) Legacy project, encapsulate one of the primary objectives of the Spitzer mission: to connect the evolution of galaxies from the distant, or early, universe to the nearby, or present day, universe.

    The Tadpole galaxy (main image) is the result of a recent galactic interaction in the local universe. Although these galactic mergers are rare in the universe's recent history, astronomers believe that they were much more common in the early universe. Thus, SWIRE team members will use this detailed image of the Tadpole galaxy to help understand the nature of the 'faint red-orange specks' of the early universe.

    The larger picture (figure 2) depicts one-sixteenth of the SWIRE survey field called ELAIS-N1. In this image, the bright blue sources are hot stars in our own Milky Way, which range anywhere from 3 to 60 times the mass of our Sun. The fainter green spots are cooler stars and galaxies beyond the Milky Way whose light is dominated by older stellar populations. The red dots are dusty galaxies that are undergoing intense star formation. The faintest specks of red-orange are galaxies billions of light-years away in the distant universe.

    Figure 3 features an unusual ring-like galaxy called CGCG 275-022. The red spiral arms indicate that this galaxy is very dusty and perhaps undergoing intense star formation. The star-forming activity could have been initiated by a near head-on collision with another galaxy.

    The most distant galaxies that SWIRE is able to detect are revealed in a zoom of deep space (figure 4). The colors in this feature represent the same objects as those in the larger field image of ELAIS

  12. Stimulus Plan Aids Education: House Bill Could Provide $100 Billion to K-12 Schools

    ERIC Educational Resources Information Center

    Klein, Alyson

    2009-01-01

    Cash-strapped school districts could see an unprecedented $100 billion infusion of federal aid under a massive economic-stimulus package unveiled by House Democrats this week. The overall measure, put forth January 15 by the House Appropriations Committee, is aimed at providing a $825 billion jolt to the stumbling U.S. economy, and to help avert…

  13. Photovoltaic Impact Assessment of Smart Inverter Volt-VAR Control on Distribution System Conservation Voltage Reduction and Power Quality

    SciTech Connect

    Ding, Fei; Nagarajan, Adarsh; Chakraborty, Sudipta; Baggu, Murali; Nguyen, Andu; Walinga, Sarah; McCarty, Michael; Bell, Frances

    2016-12-01

    This report presents an impact assessment study of distributed photovoltaic (PV) with smart inverter Volt-VAR control on conservation voltage reduction (CVR) energy savings and distribution system power quality. CVR is a methodology of flattening and lowering a distribution system voltage profile in order to conserve energy. Traditional CVR relies on operating utility voltage regulators and switched capacitors. However, with the increased penetration of distributed PV systems, smart inverters provide the new opportunity to control local voltage and power factor by regulating the reactive power output, leading to a potential increase in CVR energy savings. This report proposes a methodology to implement CVR scheme by operating voltage regulators, capacitors, and autonomous smart inverter Volt-VAR control in order to achieve increased CVR benefit. Power quality is an important consideration when operating a distribution system, especially when implementing CVR. It is easy to measure the individual components that make up power quality, but a comprehensive method to incorporate all of these values into a single score has yet to be undertaken. As a result, this report proposes a power quality scoring mechanism to measure the relative power quality of distribution systems using a single number, which is aptly named the 'power quality score' (PQS). Both the CVR and PQS methodologies were applied to two distribution system models, one obtained from the Hawaiian Electric Company (HECO) and another obtained from Pacific Gas and Electric (PG&E). These two models were converted to the OpenDSS platform using previous model conversion tools that were developed by NREL. Multiple scenarios including various PV penetration levels and smart inverter densities were simulated to analyze the impact of smart inverter Volt-VAR support on CVR energy savings and feeder power quality. In order to analyze the CVR benefit and PQS, an annual simulation was conducted for each scenario.

  14. Investigating fusion plasma instabilities in the Mega Amp Spherical Tokamak using mega electron volt proton emissions (invited)

    SciTech Connect

    Perez, R. V. Boeglin, W. U.; Angulo, A.; Avila, P.; Leon, O.; Lopez, C.; Darrow, D. S.; Cecconello, M.; Klimek, I.; Allan, S. Y.; Akers, R. J.; Keeling, D. L.; McClements, K. G.; Scannell, R.; Conway, N. J.; Turnyanskiy, M.; Jones, O. M.; Michael, C. A.

    2014-11-15

    The proton detector (PD) measures 3 MeV proton yield distributions from deuterium-deuterium fusion reactions within the Mega Amp Spherical Tokamak (MAST). The PD’s compact four-channel system of collimated and individually oriented silicon detectors probes different regions of the plasma, detecting protons (with gyro radii large enough to be unconfined) leaving the plasma on curved trajectories during neutral beam injection. From first PD data obtained during plasma operation in 2013, proton production rates (up to several hundred kHz and 1 ms time resolution) during sawtooth events were compared to the corresponding MAST neutron camera data. Fitted proton emission profiles in the poloidal plane demonstrate the capabilities of this new system.

  15. Investigating fusion plasma instabilities in the Mega Amp Spherical Tokamak using mega electron volt proton emissions (invited).

    PubMed

    Perez, R V; Boeglin, W U; Darrow, D S; Cecconello, M; Klimek, I; Allan, S Y; Akers, R J; Keeling, D L; McClements, K G; Scannell, R; Turnyanskiy, M; Angulo, A; Avila, P; Leon, O; Lopez, C; Jones, O M; Conway, N J; Michael, C A

    2014-11-01

    The proton detector (PD) measures 3 MeV proton yield distributions from deuterium-deuterium fusion reactions within the Mega Amp Spherical Tokamak (MAST). The PD's compact four-channel system of collimated and individually oriented silicon detectors probes different regions of the plasma, detecting protons (with gyro radii large enough to be unconfined) leaving the plasma on curved trajectories during neutral beam injection. From first PD data obtained during plasma operation in 2013, proton production rates (up to several hundred kHz and 1 ms time resolution) during sawtooth events were compared to the corresponding MAST neutron camera data. Fitted proton emission profiles in the poloidal plane demonstrate the capabilities of this new system.

  16. Mega-electron-volt proton irradiation on supported and suspended graphene: A Raman spectroscopic layer dependent study

    SciTech Connect

    Mathew, S.; Thong, John T. L.; Chan, T. K.; Breese, M. B. H.; Zhan, D.; Shen, Z. X.; Gopinadhan, K.; Dhar, S.; Venkatesan, T.; Roy Barman, A.

    2011-10-15

    Graphene samples with 1, 2, and 4 layers and 1 + 1 folded bi-layers and graphite have been irradiated with 2 MeV protons at fluences ranging from 1 x 10{sup 15} to 6 x 10{sup 18} ions/cm{sup 2}. The samples were characterized using visible and UV Raman spectroscopy and Raman microscopy. The ion-induced defects were found to decrease with increasing number of layers. Graphene samples suspended over etched holes in SiO{sub 2} have been fabricated and used to investigate the influence of the substrate SiO{sub 2} for defect creation in graphene. While Raman vibrational modes at 1460 cm{sup -1} and 1555 cm{sup -1} have been observed in the visible Raman spectra of substantially damaged graphene samples, these modes were absent in the irradiated-suspended monolayer graphene.

  17. Measurement of Charge Transfer Rate Coefficient Between Ground-State N(2+) Ion and He at Electron-Volt Energies

    NASA Technical Reports Server (NTRS)

    Fang, Z.; Kwong, Victor H. S.

    1997-01-01

    The charge transfer rate coefficient for the reaction N(2+)(2p(sup 2)P(sup 0)) + He yields products is measured by recording the time dependence of the N(2+) ions stored in an ion trap. A cylindrical radio-frequency ion trap was used to store N(2+) ions produced by laser ablation of a solid titanium nitride target. The decay of the ion signals was analyzed by single exponential least-squares fits to the data. The measured rate coefficient is 8.67(0.76) x 10(exp -11)sq cm/s. The N(2+) ions were at a mean energy of 2.7 eV while He gas was at room temperature, corresponding to an equivalent temperature of 3.9 x 10(exp 3) K. The measured value is in good agreement with a recent calculation.

  18. Charge Transfer Between Ground-State N(2+) and H2, N2, and CO at Electron-Volt Energies

    NASA Technical Reports Server (NTRS)

    Fang, Z.; Kwong, Victor H. S.

    1997-01-01

    The charge-transfer rate coefficients for reactions of N(2+)(2 S(sup 2)2p(sup 2)P(sup 0)) with H2, N2, and CO are measured using ion storage. A cylindrical rf ion trap was used to store N(2+) ions produced by laser ablation of a solid titanium nitride target. The rate coefficients were derived from the decay rate of the ion signal. The rate coefficients for the above three reactions are 3.38(0.35) x 10(exp -11)sq sm/s at T(sub equiv.)=2.9 x 10(exp 3) K, 2.10(0.18) x 10(exp -9)sq sm/s at T(sub equiv.) = 1.3 x 10(exp 4) K, and 3.37(0.29) x 10(exp -9)sq cm/s at T(sub equiv.) = 1.3 x 10(exp 4) K, respectively. No theoretical or other experimental values are available at this energy range.

  19. Super-Radiant Free Electron Laser Measurement and Detection

    DTIC Science & Technology

    2013-09-01

    mrad Milli-Radian mV Milli-Volt mW Milli-Watt µm Micro-Meter µV Micro-Volt OAP Off-Axis Parabolic pC Pico-Coulomb ps Picosecond QCL...A picture of a three spoke cavity is seen in Figure 1. Figure 1. Cutaway of three spoke cavity. From [1] The spoke cavity shown has four sections...where the electron beam can be accelerated by the RF fields. In between the four sections are three spoke sections that shield the electron bunches

  20. A large neutral fraction of cosmic hydrogen a billion years after the Big Bang.

    PubMed

    Wyithe, J Stuart B; Loeb, Abraham

    2004-02-26

    The fraction of ionized hydrogen left over from the Big Bang provides evidence for the time of formation of the first stars and quasar black holes in the early Universe; such objects provide the high-energy photons necessary to ionize hydrogen. Spectra of the two most distant known quasars show nearly complete absorption of photons with wavelengths shorter than the Lyman alpha transition of neutral hydrogen, indicating that hydrogen in the intergalactic medium (IGM) had not been completely ionized at a redshift of z approximately 6.3, about one billion years after the Big Bang. Here we show that the IGM surrounding these quasars had a neutral hydrogen fraction of tens of per cent before the quasar activity started, much higher than the previous lower limits of approximately 0.1 per cent. Our results, when combined with the recent inference of a large cumulative optical depth to electron scattering after cosmological recombination therefore suggest the presence of a second peak in the mean ionization history of the Universe.

  1. Billion here, a billion there - a review and analysis of synthetic-fuels development under Title I of the Energy Security Act

    SciTech Connect

    Contratto, D.C.

    1980-01-01

    Title I of the Energy Security Act launched a synthetic fuels program that could produce 2 billion barrels of fuel per day by 1992 and could cost $88 billion. A review of the Act's statutory language to see how implementation will take place and to identify potential problems and opportunities concludes that there is room for creative use of the money in the institutional structure. It will be up to those in charge of implementing the Act to seek out and develop these opportunities. 271 references.

  2. Amorphous-diamond electron emitter

    DOEpatents

    Falabella, Steven

    2001-01-01

    An electron emitter comprising a textured silicon wafer overcoated with a thin (200 .ANG.) layer of nitrogen-doped, amorphous-diamond (a:D-N), which lowers the field below 20 volts/micrometer have been demonstrated using this emitter compared to uncoated or diamond coated emitters wherein the emission is at fields of nearly 60 volts/micrometer. The silicon/nitrogen-doped, amorphous-diamond (Si/a:D-N) emitter may be produced by overcoating a textured silicon wafer with amorphous-diamond (a:D) in a nitrogen atmosphere using a filtered cathodic-arc system. The enhanced performance of the Si/a:D-N emitter lowers the voltages required to the point where field-emission displays are practical. Thus, this emitter can be used, for example, in flat-panel emission displays (FEDs), and cold-cathode vacuum electronics.

  3. Causal Analysis of the Inadvertent Contact with an Uncontrolled Electrical Hazardous Energy Source (120 Volts AC)

    SciTech Connect

    David E. James; Dennis E. Raunig; Sean S. Cunningham

    2014-10-01

    On September 25, 2013, a Health Physics Technician (HPT) was performing preparations to support a pneumatic transfer from the HFEF Decon Cell to the Room 130 Glovebox in HFEF, per HFEF OI 3165 section 3.5, Field Preparations. This activity involves an HPT setting up and climbing a portable ladder to remove the 14-C meter probe from above ball valve HBV-7. The HPT source checks the meter and probe and then replaces the probe above HBV-7, which is located above Hood ID# 130 HP. At approximately 13:20, while reaching past the HBV-7 valve position indicator switches in an attempt to place the 14-C meter probe in the desired location, the HPT’s left forearm came in contact with one of the three sets of exposed terminals on the valve position indication switches for HBV 7. This resulted in the HPT receiving an electrical shock from a 120 Volt AC source. Upon moving the arm, following the electrical shock, the HPT noticed two exposed electrical connections on a switch. The HPT then notified the HFEF HPT Supervisor, who in turn notified the MFC Radiological Controls Manager and HFEF Operations Manager of the situation. Work was stopped in the area and the hazard was roped off and posted to prevent access to the hazard. The HPT was escorted by the HPT Supervisor to the MFC Dispensary and then preceded to CFA medical for further evaluation. The individual was evaluated and released without any medical restrictions. Causal Factor (Root Cause) A3B3C01/A5B2C08: - Knowledge based error/Attention was given to wrong issues - Written Communication content LTA, Incomplete/situation not covered The Causal Factor (root cause) was attention being given to the wrong issues during the creation, reviews, verifications, and actual performance of HFEF OI-3165, which covers the need to perform the weekly source check and ensure placement of the probe prior to performing a “rabbit” transfer. This resulted in the hazard not being identified and mitigated in the procedure. Work activities

  4. Monochromatic electron photoemission from diamondoid monolayers

    SciTech Connect

    Yang, Wanli; Yang, Wanli L.; Fabbri, J.D.; Willey, T.M.; Lee, J.R.I.; Dahl, J.E.; Carlson, R.M.K.; Schreiner, P.R.; Fokin, A.A.; Tkachenko, B.A.; Fokina, N.A.; Meevasana, W.; Mannella, N.; Tanaka, K.; Zhou, X.J.; van Buuren, T.; Kelly, M.A.; Hussain, Z.; Melosh, N.A.; Shen, Z.-X.

    2007-02-27

    We found monochromatic electron photoemission from large-area self-assembled monolayers of a functionalized diamondoid, [121]tetramantane-6-thiol. Photoelectron spectra of the diamondoid monolayers exhibited a peak at the low-kinetic energy threshold; up to 68percent of all emitted electrons were emitted within this single energy peak. The intensity of the emission peak is indicative of diamondoids being negative electron affinity materials. With an energy distribution width of less than 0.5 electron volts, this source of monochromatic electrons may find application in technologies such as electron microscopy, electron beam lithography, and field-emission flatpanel displays.

  5. Monochromatic Electron Photoemission from DiamondoidMonolayers

    SciTech Connect

    Yang, W.L.

    2010-04-15

    We found monochromatic electron photoemission from large-area self-assembled monolayers of a functionalized diamondoid, [121]tetramantane-6-thiol. Photoelectron spectra of the diamondoid monolayers exhibited a peak at the low-kinetic energy threshold; up to 68% of all emitted electrons were emitted within this single energy peak. The intensity of the emission peak is indicative of diamondoids being negative electron affinity materials. With an energy distribution width of less than 0.5 electron volts, this source of monochromatic electrons may find application in technologies such as electron microscopy, electron beam lithography, and field-emission flat-panel displays.

  6. Reliability, performance characteristics, construct validity, and an initial clinical application of a visual object learning test (VOLT).

    PubMed

    Glahn, D C; Gur, R C; Ragland, J D; Censits, D M; Gur, R E

    1997-10-01

    Whereas verbal learning has received considerable attention by cognitive neuropsychology, spatial object learning has been more resistant to study. The paucity of visual learning data has hampered attempts to clarify if visual learning has unique features with specialized neural substrates. In schizophrenia, severe verbal learning impairment has been established, but lack of comparable visual learning measures has thwarted the dissociation of verbal and visual abilities. The Visual Object Learning Test (VOLT) was developed to examine aspects of visual-spatial learning and memory in a manner analogous to available verbal tests. Studies were performed to establish normative performance characteristics, convergent and divergent validity, and the sensitivity of the VOLT to detection of individual differences in normal (through sex and age) and pathologic variability (through persons with schizophrenia). The results indicated excellent internal consistency, convergent and divergent validity, and sensitivity to the effects of aging and pathology. Persons with schizophrenia were impaired in both learning and retention. The authors conclude that memory impairment in schizophrenia may not be specific to verbal learning.

  7. Rules Set for $4 Billion Race to Top Contest: Final Rules Give States Detailed Map in Quest for $4 Billion in Education Stimulus Aid

    ERIC Educational Resources Information Center

    McNeil, Michele

    2009-01-01

    For a good shot at $4 billion in grants from the federal Race to the Top Fund, states will need to make a persuasive case for their education reform agendas, demonstrate significant buy-in from local school districts, and devise plans to evaluate teachers and principals based on student performance, according to final regulations released last…

  8. Lewin estimates 2 billion barrels of US tar sand recoverable at mid $20/bbl

    SciTech Connect

    Not Available

    1986-12-01

    In 1983, Lewin and Associates prepared a report which established that the US tar sands resource amounts to over 60 billion barrels of bitumen in-place. However, no estimate was made of the technically or economically recoverable portion of this resource. More recent work carried out by Lewin for the US Department of Energy presents an appraisal of technically and economically recoverable tar sands. The paper describes the tar sand resource in-place, tar sand recovery models used in the study, engineering cost models, the economics of the steam soak prospect, and the economics of a surface mining prospect. The results of the Lewin study show that 5.7 billion barrels of domestic tar sand are technically recoverable, using cyclic steam injection and surface extractive mining. Of this, 4.9 billion barrels are technically recoverable from surface mining methods, with 0.8 billion recoverable from steam soak applications. 1 figure, 3 tables.

  9. Change in operating parameters of the Continuous Electron Beam Accelerator Facility and Free Electron Laser, Thomas Jefferson National Accelerator Facility, Newport News, Virginia

    SciTech Connect

    1997-10-01

    In this environmental assessment (EA), the US Department of Energy (DOE) reports the results of an analysis of the potential environmental impacts from a proposed change in operating parameters of the Continuous Electron Beam Accelerator Facility (CEBAF), and operation of the Free Electron Laser (FEL) facility beyond the initial demonstration period. With this proposal, DOE intends to increase CEBAF operating range from its current operating maximum beam energy of 4.0 GeV [giga-(billion) electron volts] to 8.0 GeV at a beam power of no greater than 1,000 kW [1 megawatt (MW)], its maximum attainable level, based on current technology and knowledge, without significant, costly equipment modifications. DOE has prepared an EA for this action to determine the potential for adverse impacts from operation of CEBAF and the FEL at the proposed levels. Changing the operating parameters of CEBAF would require no new major construction and minor modifications to the accelerator, its support systems, the FEL, and onsite utility systems. Modifications and performance improvements would be made to (1) the accelerator housed in the underground tunnels, (2) its support systems located in the above ground service buildings, and (3) the water and equipment cooling systems both in the tunnel and at the ground surface. All work would be performed on previously disturbed land and in, on, or adjacent to existing buildings, structures, and equipment. With the proposed action, the recently constructed FEL facility at the Jefferson Lab would operate in concert with CEBAF beyond its demonstration period and up to its maximum effective electron beam power level of 210 kW. In this EA, DOE evaluates the impacts of the no-action alternative and the proposed action alternative. Alternatives considered, but dismissed from further evaluation, were the use of another accelerator facility and the use of another technology.

  10. 33 CFR 183.430 - Conductors in circuits of less than 50 volts.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... insulating material temperature rating requirements of SAE Standard J378; and (ii) SAE Standard J1127, or SAE Standard 1128. (b) This section does not apply to communication systems; electronic navigation...

  11. Expert fears doom if world population hits 12-15 billion.

    PubMed

    1994-02-22

    Earth's land, water and cropland are disappearing so rapidly that the world population must be slashed to 2 billion or less by 2100 to provide prosperity for all in that year, says a study released yesterday. The alternative, if current trends continue, is a population of 12 billion to 15 billion people and an apocalyptic worldwide scene of "absolute misery, poverty, disease and starvation," said the study's author, David Pimentel, an ecologist at Cornell University. In the US, the population would climb to 500 million and the standard of living would decline to slightly better than in present-day China. Mr. Pimentel said at the annual meeting of the American Association for the Advancement of Science. Even now, the world population of 6 billion is at least 3 times what the Earth's battered natural resources and depleted energy reserves would be able to comfortably support in 2100, Mr. Pimentel said. Mr. Pimentel defines "comfortably support" as providing something close to the current American standard of living, but with wiser use of energy and natural resources. Although a decline to 1 billion or 2 billion people over the next century sounds nearly impossible, it could be done by limiting families around the world to an average of 1.5 children, Mr. Pimentel said. Currently, US women have an average of 2.1 children, while the average in Rwanda is 8.5.

  12. Effect of gigaelectron volt Au-ion irradiation on the characteristics of ultrananocrystalline diamond films

    SciTech Connect

    Chen, Huang-Chin; Teng, Kuang-Yau; Tang, Chen-Yau; Lin, I-Nan; Sundaravel, Balakrishnan; Amirthapandian, Sankarakumar

    2010-12-15

    The effect of 2.245 GeV Au-ion irradiation/postannealing processes on the electron field emission (EFE) properties of ultrananocrystalline diamond (UNCD) films was investigated. Au-ion irradiation with a fluence of around 8.4x10{sup 13} ions/cm{sup 2} is required to induce a large improvement in the EFE properties of the UNCD films. Postannealing the Au-ion irradiated films at 1000 deg. C for 1 h slightly degraded the EFE properties of the films but the resulting EFE behavior was still markedly superior to that of pristine UNCD films. Transmission electron microscopy examinations revealed that the EFE properties of the UNCD films are primarily improved by Au-ion irradiation/postannealing processes because of the formation of nanographites along the trajectory of the irradiating ions, which results in an interconnected path for electron transport. In contrast, the induction of grain growth process due to Au-ion irradiation in UNCD films is presumed to insignificantly degrade the EFE properties for the films as the aggregates are scarcely distributed and do not block the electron conducting path.

  13. Acceleration of uranium at the Bevalac

    SciTech Connect

    Alonso, J.R.; Avery, R.T.; Elioff, T.; Force, R.J.; Grunder, H.A.; Lancaster, H.D.; Lofgren, E.J.; Meneghetti, J.R.; Selph, F.B.; Stevenson, R.R.

    1982-09-17

    Recent upgrading projects have extended the mass range of particles that can be accelerated at the Bevalac to include any element of the periodic table to energies above 1 billion electron volts per atomic mass unit. This capability was verified on 11 May 1982 with the production of a uranium beam at 147.7 million electron volts per atomic mass unit.

  14. Regional Feedstock Partnership Summary Report: Enabling the Billion-Ton Vision

    SciTech Connect

    Owens, Vance N.; Karlen, Douglas L.; Lacey, Jeffrey A.

    2016-07-12

    The U.S. Department of Energy (DOE) and the Sun Grant Initiative established the Regional Feedstock Partnership (referred to as the Partnership) to address information gaps associated with enabling the vision of a sustainable, reliable, billion-ton U.S. bioenergy industry by the year 2030 (i.e., the Billion-Ton Vision). Over the past 7 years (2008–2014), the Partnership has been successful at advancing the biomass feedstock production industry in the United States, with notable accomplishments. The Billion-Ton Study identifies the technical potential to expand domestic biomass production to offset up to 30% of U.S. petroleum consumption, while continuing to meet demands for food, feed, fiber, and export. This study verifies for the biofuels and chemical industries that a real and substantial resource base could justify the significant investment needed to develop robust conversion technologies and commercial-scale facilities. DOE and the Sun Grant Initiative established the Partnership to demonstrate and validate the underlying assumptions underpinning the Billion-Ton Vision to supply a sustainable and reliable source of lignocellulosic feedstock to a large-scale bioenergy industry. This report discusses the accomplishments of the Partnership, with references to accompanying scientific publications. These accomplishments include advances in sustainable feedstock production, feedstock yield, yield stability and stand persistence, energy crop commercialization readiness, information transfer, assessment of the economic impacts of achieving the Billion-Ton Vision, and the impact of feedstock species and environment conditions on feedstock quality characteristics.

  15. Inventory Control. Easily Made Electronic Device for Conductivity Experiments.

    ERIC Educational Resources Information Center

    Gadek, Frank J.

    1987-01-01

    Describes how to construct an electronic device to be used in conductivity experiments using a 35 millimeter film canister, nine volt battery replacement snaps, a 200-300 ohm resistor, and a light-emitting diode. Provides a diagram and photographs of the device. (TW)

  16. Birth of the Kaapvaal tectosphere 3.08 billion years ago.

    PubMed

    Moser, D E; Flowers, R M; Hart, R J

    2001-01-19

    The crustal remnants of Earth's Archean continents have been shielded from mantle convection by thick roots of ancient mantle lithosphere. The precise time of crust-root coupling (tectosphere birth) is poorly known but is needed to test competing theories of continental plate genesis. Our mapping and geochronology of an impact-generated section through the Mesoarchean crust of the Kaapvaal craton indicates tectosphere birth at 3.08 +/- 0.01 billion years ago, roughly 0.12 billion years after crust assembly. Growth of the southern African mantle root by subduction processes occurred within about 0.2 billion years. The assembly of crust before mantle may be common to the tectosphere.

  17. 3.4-Billion-year-old biogenic pyrites from Barberton, South Africa: sulfur isotope evidence.

    PubMed

    Ohmoto, H; Kakegawa, T; Lowe, D R

    1993-10-22

    Laser ablation mass spectroscopy analyses of sulfur isotopic compositions of microscopic-sized grains of pyrite that formed about 3.4 billion years ago in the Barberton Greenstone Belt, South Africa, show that the pyrite formed by bacterial reduction of seawater sulfate. These data imply that by about 3.4 billion years ago sulfate-reducing bacteria had become active, the oceans were rich in sulfate, and the atmosphere contained appreciable amounts (>10(-13) of the present atmospheric level) of free oxygen.

  18. 3.4-Billion-year-old biogenic pyrites from Barberton, South Africa: sulfur isotope evidence

    NASA Technical Reports Server (NTRS)

    Ohmoto, H.; Kakegawa, T.; Lowe, D. R.

    1993-01-01

    Laser ablation mass spectroscopy analyses of sulfur isotopic compositions of microscopic-sized grains of pyrite that formed about 3.4 billion years ago in the Barberton Greenstone Belt, South Africa, show that the pyrite formed by bacterial reduction of seawater sulfate. These data imply that by about 3.4 billion years ago sulfate-reducing bacteria had become active, the oceans were rich in sulfate, and the atmosphere contained appreciable amounts (>>10(-13) of the present atmospheric level) of free oxygen.

  19. Billions for biodefense: federal agency biodefense funding, FY2001-FY2005.

    PubMed

    Schuler, Ari

    2004-01-01

    Over the past several years, the United States government has spent substantial resources on preparing the nation against a bioterrorist attack. This article analyzes the civilian biodefense funding by the federal government from fiscal years 2001 through 2005, specifically analyzing the budgets and allocations for biodefense at the Department of Health and Human Services, the Department of Homeland Security, the Department of Defense, the Department of Agriculture, the Environmental Protection Agency, the National Science Foundation, and the Department of State. In total, approximately $14.5 billion has been funded for civilian biodefense through FY2004, with an additional $7.6 billion in the President's budget request for FY2005.

  20. An instrument for the direct measurement of electron temperature in the ionosphere

    NASA Astrophysics Data System (ADS)

    Markov, V.; Genov, V.; Bliznakov, K.

    An instrument based on a modified Langmuir-probe method is described which is used to measure ratios of the electron currents of two identical probes in the electron-deceleration region of the volt-ampere characteristics. The instrument makes it possible to perform precise measurements of temperature with a relatively simple processing method. A block diagram of the instrument is presented.

  1. Negative-ion formation in the explosives RDX, PETN, and TNT using the Reversal Electron Attachment Detection (READ) technique

    NASA Technical Reports Server (NTRS)

    Chutijian, Ara; Boumsellek, S.; Alajajian, S. H.

    1992-01-01

    In the search for high sensitivity and direct atmospheric sampling of trace species, techniques have been developed such as atmospheric-sampling, glow-discharge ionization (ASGDI), corona discharge, atmospheric pressure ionization (API), electron-capture detection (ECD), and negative-ion chemical ionization (NICI) that are capable of detecting parts-per-billion to parts-per-trillion concentrations of trace species. These techniques are based on positive- or negative-ion formation via charge-transfer to the target, or electron capture under multiple-collision conditions in a Maxwellian distribution of electron energies at the source temperature. One drawback of the high-pressure, corona- or glow-discharge devices is that they are susceptible to interferences either through indistinguishable product masses, or through undesired ion-molecule reactions. The ASGDI technique is relatively immune from such interferences, since at target concentrations of less than 1 ppm the majority of negative ions arises via electron capture rather than through ion-molecule chemistry. A drawback of the conventional ECD, and possibly of the ASGDI, is that they exhibit vanishingly small densities of electrons with energies in the range 0-10 millielectron volts (meV), as can be seen from a typical Maxwellian electron energy distribution function at T = 300 K. Slowing the electrons to these subthermal (less than 10 meV) energies is crucial, since the cross section for attachment of several large classes of molecules is known to increase to values larger than 10(exp -12) sq cm at near-zero electron energies. In the limit of zero energy these cross sections are predicted to diverge as epsilon(exp -1/2), where epsilon is the electron energy. In order to provide a better 'match' between the electron energy distribution function and attachment cross section, a new concept of attachment in an electrostatic mirror was developed. In this scheme, electrons are brought to a momentary halt by

  2. Multi-Billion Shot, High-Fluence Exposure of Cr(4+): YAG Passive Q-Switch

    NASA Technical Reports Server (NTRS)

    Stephen, Mark A.; Dallas, Joseph L.; Afzal, Robert S.

    1997-01-01

    NASA's Goddard Space Flight Center is developing the Geoscience Laser Altimeter System (GLAS) employing a diode pumped, Q-Switched, ND:YAG laser operating at 40 Hz repetition rate. To meet the five-year mission lifetime goal, a single transmitter would accumulate over 6.3 billion shots. Cr(4+):YAG is a promising candidate material for passively Q-switching the laser. Historically, the performance of saturable absorbers has degraded over long-duration usage. To measure the multi-billion shot performance of Cr(4+):YAG, a passively Q-switched GLAS-like oscillator was tested at an accelerated repetition rate of 500 Hz. The intracavity fluence was calculated to be approximately 2.5 J/cm(exp 2). The laser was monitored autonomously for 165 days. There was no evidence of change in the material optical properties during the 7.2 billion shot test.. All observed changes in laser operation could be attributed to pump laser diode aging. This is the first demonstration of multi-billion shot exposure testing of Cr(4+):YAG in this pulse energy regime

  3. Two Billion Cars: What it Means for Climate and Energy Policy

    ScienceCinema

    Daniel Sperling

    2016-07-12

    April 13, 2009: Daniel Sperling, director of the Institute of Transportation Studies at UC Davis, presents the next installment of Berkeley Lab's Environmental Energy Technologies Divisions Distinguished Lecture series. He discusses Two Billion Cars and What it Means for Climate and Energy Policy.

  4. 2016 Billion-Ton Report: Advancing Domestic Resources for a Thriving Bioeconomy

    SciTech Connect

    Langholtz, M. H.; Stokes, B. J.; Eaton, L. M.

    2016-07-06

    This product builds on previous efforts, namely the 2005 Billion-Ton Study (BTS) and the 2011 U.S. Billion-Ton Update (BT2).With each report, greater perspective is gained on the potential of biomass resources to contribute to a national energy strategy. Similarly, each successive report introduces new questions regarding commercialization challenges. BTS quantified the broad biophysical potential of biomass nationally, and BT2 elucidated the potential economic availability of these resources. These reports clearly established the potential availability of up to one billion tons of biomass resources nationally. However, many questions remain, including but not limited to crop yields, climate change impacts, logistical operations, and systems integration across production, harvest, and conversion. The present report aims to address many of these questions through empirically modeled energy crop yields, scenario analysis of resources delivered to biorefineries, and the addition of new feedstocks. Volume 2 of the 2016 Billion-Ton Report is expected to be released by the end of 2016. It seeks to evaluate environmental sustainability indicators of select scenarios from volume 1 and potential climate change impacts on future supplies.

  5. The uncertain timing of reaching 8 billion, peak world population, and other demographic milestones.

    PubMed

    Scherbov, Sergei; Lutz, Wolfgang Lutz; Sanderson, Warren C

    2011-01-01

    We present new probabilistic forecasts of the timing of the world's population reaching 8 billion, the world's peak population, and the date at which one-third or more of the world's population would be 60+ years old. The timing of these milestones, as well as the timing of the Day of 7 Billion, is uncertain. We compute that the 60 percent prediction interval for the Day of 8 Billion is between 2024 and 2033. Our figures show that there is around a 60 percent chance that one-third of the world's population would be 60+ years old in 2100. In the UN 2010 medium variant, that proportion never reaches one-third. As in our past forecasts (Lutz et al. 2001, 2008), we find the chance that the world's population will peak in this century to be around 84 percent and the timing of that peak to be highly uncertain. Focal days, like the Day of 7 Billion, play a role in raising public awareness of population issues, but they give a false sense of the certainty of our knowledge. The uncertainty of the timing of demographic milestones is not a constant of nature. Understanding the true extent of our demographic uncertainty can help motivate governments and other agencies to make the investments necessary to reduce it.

  6. High-Stakes Hustle: Public Schools and the New Billion Dollar Accountability

    ERIC Educational Resources Information Center

    Baines, Lawrence A.; Stanley, Gregory Kent

    2004-01-01

    High-stakes testing costs up to $50 billion per annum, has no impact on student achievement, and has changed the focus of American public schools. This article analyzes the benefits and costs of the accountability movement, as well as discusses its roots in the eugenics movements of the early 20th century.

  7. Conservation in a World of Six Billion: A Grassroots Action Guide.

    ERIC Educational Resources Information Center

    Hren, Benedict J.

    This grassroots action guide features a conservation initiative working to bring the impacts of human population growth, economic development, and natural resource consumption into balance with the limits of nature for the benefit of current and future generations. Contents include information sheets entitled "Six Billion People and Growing,""The…

  8. U.S. Health Care Costs from Birth Defects Total Almost $23 Billion a Year

    MedlinePlus

    ... https://medlineplus.gov/news/fullstory_163141.html U.S. Health Care Costs From Birth Defects Total Almost $23 Billion ... U.S. newborns have a serious birth defect, and health care costs tied to these difficulties total almost $23 ...

  9. Universities Report $1.8-Billion in Earnings on Inventions in 2011

    ERIC Educational Resources Information Center

    Blumenstyk, Goldie

    2012-01-01

    Universities and their inventors earned more than $1.8-billion from commercializing their academic research in the 2011 fiscal year, collecting royalties from new breeds of wheat, from a new drug for the treatment of HIV, and from longstanding arrangements over enduring products like Gatorade. Northwestern University earned the most of any…

  10. Mass spectrometry at and below 0.1 parts per billion

    SciTech Connect

    Bradley, M.; Palmer, F.; Pritchard, D.E.

    1994-12-31

    The single ion Penning trap mass spectrometer at M.I.T. can compare masses to within 0.1 parts per billion. We have created a short table of fundamental atomic masses and made measurements useful for calibrating the X-ray standard, and determining Avogadro`s number, the molar Plank constant, and the fine structure constant.

  11. Two Billion Cars: What it Means for Climate and Energy Policy

    SciTech Connect

    Daniel Sperling

    2009-04-15

    April 13, 2009: Daniel Sperling, director of the Institute of Transportation Studies at UC Davis, presents the next installment of Berkeley Lab's Environmental Energy Technologies Divisions Distinguished Lecture series. He discusses Two Billion Cars and What it Means for Climate and Energy Policy.

  12. Measurement of volt/meter vertical electric fields in the middle atmosphere

    NASA Technical Reports Server (NTRS)

    Maynard, N. C.; Croskey, C. L.; Mitchell, J. D.; Hale, L. C.

    1981-01-01

    A test flight for a series of middle atmosphere electrodynamics rockets was launched from Wallops Island, Virginia, at 7:18 EST on July 31, 1980. The mother-daughter configuration contained a three axis symmetric double probe electric field instrument and a blunt probe on the daughter payload, and a Gerdien condenser and a single axis (vertical) asymmetric double probe electric field instrument on the mother payload. The payloads reached an apogee of 111 km, and data were gathered from all instruments on the downleg. A downward vertical electric field with a maximum amplitude of about 4 V/m was observed in a layer between about 57 and 67 km. The integrated potential across this layer was approximately 20 kV. Conductivity measurements indicated that free electrons were absent from the region of large electric fields; however, the decrease in conductivity was insufficient to maintain vertical current continuity through the layer. These results establish the existence of large mesospheric electric fields, supporting previous results from single axis measurements.

  13. Impacts of Varying Penetration of Distributed Resources with & without Volt/Var Control: Case Study of Varying Load Types

    SciTech Connect

    Rizy, D Tom; Li, Huijuan; Li, Fangxing; Xu, Yan; Adhikari, Sarina; Irminger, Philip

    2011-01-01

    This paper provides a follow-up to an earlier one on impacts of distributed energy resources (DR) on distribution feeders. As DR penetration level on the feeder increases, there can be impacts to distribution system/feeder capacity, line losses, and voltage regulation. These can vary as the penetration level reaches the capacity of the distribution feeder/system or loading. The question is how high of a DR level can be accommodated without any major changes to system operation, system design and protection. Our objective for this work was to address the question of how the DR impacts vary in regards to both DR voltage regulation capability and load mix. A dynamic analysis was used to focus on the impacts of DR with and without volt/var control with different load composition on the distribution feeder. The study considered an example 10MVA distribution feeder in which two inverter-based DRs were used to provide voltage regulation. The results due to DR without voltage regulation capability are compared with DR capable of providing local (at its bus) voltage regulation. The analysis was repeated for four different feeder load compositions consisting of (1) constant power, (2) constant impedance, (3) constant current and (4) ZIP (equal combination of previous three).

  14. The ExaVolt Antenna: A large-aperture, balloon-embedded antenna for ultra-high energy particle detection

    NASA Astrophysics Data System (ADS)

    Gorham, P. W.; Baginski, F. E.; Allison, P.; Liewer, K. M.; Miki, C.; Hill, B.; Varner, G. S.

    2011-12-01

    We describe the scientific motivation, experimental basis, design methodology, and simulated performance of the ExaVolt Antenna (EVA) mission, and planned ultra-high energy (UHE) particle observatory under development for NASA's suborbital super-pressure balloon program in Antarctica. EVA will improve over ANITA's integrated totals - the current state-of-the-art in UHE suborbital payloads - by 1-2 orders of magnitude in a single flight. The design is based on a novel application of toroidal reflector optics which utilizes a super-pressure balloon surface, along with a feed-array mounted on an inner membrane, to create an ultra-large radio antenna system with a synoptic view of the Antarctic ice sheet below it. Radio impulses arise via the Askaryan effect when UHE neutrinos interact within the ice, or via geosynchrotron emission when UHE cosmic rays interact in the atmosphere above the continent. EVA's instantaneous antenna aperture is estimated to be several hundred m 2 for detection of these events within a 150-600 MHz band. For standard cosmogenic UHE neutrino models, EVA should detect of order 30 events per flight in the EeV energy regime. For UHE cosmic rays, of order 15,000 geosynchrotron events would be detected in total, several hundred above 10 EeV, and of order 60 above the GZK cutoff energy.

  15. Lithium rich cathode/graphite anode combination for lithium ion cells with high tolerance to near zero volt storage

    NASA Astrophysics Data System (ADS)

    Crompton, K. R.; Staub, J. W.; Hladky, M. P.; Landi, B. J.

    2017-03-01

    Management of reversible lithium is an advantageous approach to design lithium ion cells that are tolerant to near zero volt (NZV) storage under fixed resistive load towards highly controllable, enhanced user-inactive safety. Presently, the first cycle loss from a high energy density Li-rich HE5050 cathode is used to provide excess reversible lithium when paired with an appropriately capacity matched mesocarbon microbead (MCMB) anode. Cells utilizing 1.2 M LiPF6 3:7 v/v ethylene carbonate:ethyl methyl carbonate electrolyte and a lithium reference were used for 3-electrode testing. After conditioning, a fixed resistive load was applied to 3-electrode cells for 72 or 168-h during which the anode potential and electrode asymptotic potential (EAP) remained less than the copper dissolution potential. After multiple storage cycles (room temperature or 40 °C), the NZV coulombic efficiency (cell reversibility) exceeded 97% and the discharge capacity retention was >98%. Conventional 2-electrode HE5050/MCMB pouch cells stored at NZV or open circuit for 3 days had nearly identical rate capability (up to 5C) and discharge performance stability (for 500 cycles under a 30% depth of discharge low-earth-orbit regime). Thus, lithium ion cells with appropriately capacity matched HE5050/MCMB electrodes have excellent tolerance to prolonged NZV storage, which can lead to enhanced user-inactive safety.

  16. Formation of electrostatic structures by wakefield acceleration in ultrarelativistic plasma flows: Electron acceleration to cosmic ray energies

    SciTech Connect

    Dieckmann, M.E.; Shukla, P.K.; Eliasson, B.

    2006-06-15

    The ever increasing performance of supercomputers is now enabling kinetic simulations of extreme astrophysical and laser produced plasmas. Three-dimensional particle-in-cell (PIC) simulations of relativistic shocks have revealed highly filamented spatial structures and their ability to accelerate particles to ultrarelativistic speeds. However, these PIC simulations have not yet revealed mechanisms that could produce particles with tera-electron volt energies and beyond. In this work, PIC simulations in one dimension (1D) of the foreshock region of an internal shock in a gamma ray burst are performed to address this issue. The large spatiotemporal range accessible to a 1D simulation enables the self-consistent evolution of proton phase space structures that can accelerate particles to giga-electron volt energies in the jet frame of reference, and to tens of tera-electron volt in the Earth's frame of reference. One potential source of ultrahigh energy cosmic rays may thus be the thermalization of relativistically moving plasma.

  17. Power Hardware-in-the-Loop Testing of Multiple Photovoltaic Inverters' Volt-Var Control with Real-Time Grid Model

    SciTech Connect

    Chakraborty, Sudipta; Nelson, Austin; Hoke, Anderson

    2016-12-12

    Traditional testing methods fall short in evaluating interactions between multiple smart inverters providing advanced grid support functions due to the fact that such interactions largely depend on their placements on the electric distribution systems with impedances between them. Even though significant concerns have been raised by the utilities on the effects of such interactions, little effort has been made to evaluate them. In this paper, power hardware-in-the-loop (PHIL) based testing was utilized to evaluate autonomous volt-var operations of multiple smart photovoltaic (PV) inverters connected to a simple distribution feeder model. The results provided in this paper show that depending on volt-var control (VVC) parameters and grid parameters, interaction between inverters and between the inverter and the grid is possible in some extreme cases with very high VVC slopes, fast response times and large VVC response delays.

  18. Auroral electrons of energy less than 1 keV observed at rocket altitudes.

    NASA Technical Reports Server (NTRS)

    Arnoldy, R. L.; Choy, L. W.

    1973-01-01

    Measurements of electrons of energy less than 1 keV in the auroral precipitation with detectors aboard three rocket flights are discussed. Detectors simultaneously measured the flux of electrons moving up and down the magnetic field lines. Electrons of energy less than a few hundred electron volts show directional intensities ranging from isotropic over the upper hemisphere, to field aligned into the atmosphere, to a net streaming out of the atmosphere. Cases of reflection coefficients greater than 1 for the few hundred electron volts and lower-energy electrons occur when measurements were made north of auroral forms. These electrons might represent the high-energy tail of the return Birkeland currents. The origin of the low-energy electrons is itself in question.

  19. Two billion years of magmatism recorded from a single Mars meteorite ejection site.

    PubMed

    Lapen, Thomas J; Righter, Minako; Andreasen, Rasmus; Irving, Anthony J; Satkoski, Aaron M; Beard, Brian L; Nishiizumi, Kunihiko; Jull, A J Timothy; Caffee, Marc W

    2017-02-01

    The timing and nature of igneous activity recorded at a single Mars ejection site can be determined from the isotope analyses of Martian meteorites. Northwest Africa (NWA) 7635 has an Sm-Nd crystallization age of 2.403 ± 0.140 billion years, and isotope data indicate that it is derived from an incompatible trace element-depleted mantle source similar to that which produced a geochemically distinct group of 327- to 574-million-year-old "depleted" shergottites. Cosmogenic nuclide data demonstrate that NWA 7635 was ejected from Mars 1.1 million years ago (Ma), as were at least 10 other depleted shergottites. The shared ejection age is consistent with a common ejection site for these meteorites. The spatial association of 327- to 2403-Ma depleted shergottites indicates >2 billion years of magmatism from a long-lived and geochemically distinct volcanic center near the ejection site.

  20. Two billion years of magmatism recorded from a single Mars meteorite ejection site

    PubMed Central

    Lapen, Thomas J.; Righter, Minako; Andreasen, Rasmus; Irving, Anthony J.; Satkoski, Aaron M.; Beard, Brian L.; Nishiizumi, Kunihiko; Jull, A. J. Timothy; Caffee, Marc W.

    2017-01-01

    The timing and nature of igneous activity recorded at a single Mars ejection site can be determined from the isotope analyses of Martian meteorites. Northwest Africa (NWA) 7635 has an Sm-Nd crystallization age of 2.403 ± 0.140 billion years, and isotope data indicate that it is derived from an incompatible trace element–depleted mantle source similar to that which produced a geochemically distinct group of 327- to 574-million-year-old “depleted” shergottites. Cosmogenic nuclide data demonstrate that NWA 7635 was ejected from Mars 1.1 million years ago (Ma), as were at least 10 other depleted shergottites. The shared ejection age is consistent with a common ejection site for these meteorites. The spatial association of 327- to 2403-Ma depleted shergottites indicates >2 billion years of magmatism from a long-lived and geochemically distinct volcanic center near the ejection site. PMID:28164153

  1. Billions for biodefense: federal agency biodefense funding, FY2009-FY2010.

    PubMed

    Franco, Crystal

    2009-09-01

    Since 2001, the United States government has spent substantial resources on preparing the nation against a bioterrorist attack. Earlier articles in this series analyzed civilian biodefense funding by the federal government for fiscal years (FY) 2001 through 2009. This article updates those figures with budgeted amounts for FY2010, specifically analyzing the budgets and allocations for biodefense at the Departments of Health and Human Services, Defense, Homeland Security, Agriculture, and State; the Environmental Protection Agency; and the National Science Foundation. This year's article also provides an assessment of the proportion of the biodefense budget that serves multiple programmatic goals and benefits, including research into infectious disease pathogenesis and immunology, public health planning and preparedness, and disaster response efforts. The FY2010 federal budget for civilian biodefense totals $6.05 billion. Of that total, $4.96 billion is budgeted for programs that serve multiple goals and provide manifold benefits.

  2. How to Bring Solar Energy to Seven Billion People (LBNL Science at the Theater)

    ScienceCinema

    Wadia, Cyrus

    2016-07-12

    By exploiting the powers of nanotechnology and taking advantage of non-toxic, Earth-abundant materials, Berkeley Lab's Cyrus Wadia has fabricated new solar cell devices that have the potential to be several orders of magnitude less expensive than conventional solar cells. And by mastering the chemistry of these materials-and the economics of solar energy-he envisions bringing electricity to the 1.2 billion people now living without it.

  3. Medicare, Medicaid fraud a billion-dollar art form in the US

    PubMed Central

    Korcok, M

    1997-01-01

    Medicare and Medicaid fraud costs billions of dollars each year in the US. Investigators have shown that fraud is found in all segments of the health care system. Even though the Canadian system has stricter regulations and tighter controls, can regulators here afford to be complacent about believing that such abuse would not happen here? One province has established an antifraud unit to monitor its health insurance scheme; it already has 1 prosecution under its belt. PMID:9141996

  4. A 17-billion-solar-mass black hole in a group galaxy with a diffuse core.

    PubMed

    Thomas, Jens; Ma, Chung-Pei; McConnell, Nicholas J; Greene, Jenny E; Blakeslee, John P; Janish, Ryan

    2016-04-21

    Quasars are associated with and powered by the accretion of material onto massive black holes; the detection of highly luminous quasars with redshifts greater than z = 6 suggests that black holes of up to ten billion solar masses already existed 13 billion years ago. Two possible present-day 'dormant' descendants of this population of 'active' black holes have been found in the galaxies NGC 3842 and NGC 4889 at the centres of the Leo and Coma galaxy clusters, which together form the central region of the Great Wall--the largest local structure of galaxies. The most luminous quasars, however, are not confined to such high-density regions of the early Universe; yet dormant black holes of this high mass have not yet been found outside of modern-day rich clusters. Here we report observations of the stellar velocity distribution in the galaxy NGC 1600--a relatively isolated elliptical galaxy near the centre of a galaxy group at a distance of 64 megaparsecs from Earth. We use orbit superposition models to determine that the black hole at the centre of NGC 1600 has a mass of 17 billion solar masses. The spatial distribution of stars near the centre of NGC 1600 is rather diffuse. We find that the region of depleted stellar density in the cores of massive elliptical galaxies extends over the same radius as the gravitational sphere of influence of the central black holes, and interpret this as the dynamical imprint of the black holes.

  5. Two ten-billion-solar-mass black holes at the centres of giant elliptical galaxies.

    PubMed

    McConnell, Nicholas J; Ma, Chung-Pei; Gebhardt, Karl; Wright, Shelley A; Murphy, Jeremy D; Lauer, Tod R; Graham, James R; Richstone, Douglas O

    2011-12-08

    Observational work conducted over the past few decades indicates that all massive galaxies have supermassive black holes at their centres. Although the luminosities and brightness fluctuations of quasars in the early Universe suggest that some were powered by black holes with masses greater than 10 billion solar masses, the remnants of these objects have not been found in the nearby Universe. The giant elliptical galaxy Messier 87 hosts the hitherto most massive known black hole, which has a mass of 6.3 billion solar masses. Here we report that NGC 3842, the brightest galaxy in a cluster at a distance from Earth of 98 megaparsecs, has a central black hole with a mass of 9.7 billion solar masses, and that a black hole of comparable or greater mass is present in NGC 4889, the brightest galaxy in the Coma cluster (at a distance of 103 megaparsecs). These two black holes are significantly more massive than predicted by linearly extrapolating the widely used correlations between black-hole mass and the stellar velocity dispersion or bulge luminosity of the host galaxy. Although these correlations remain useful for predicting black-hole masses in less massive elliptical galaxies, our measurements suggest that different evolutionary processes influence the growth of the largest galaxies and their black holes.

  6. Planet Earth 2025. A look into a future world of 8 billion humans.

    PubMed

    Hinrichsen, D; Rowley, J

    1999-01-01

    Population projections for the next quarter century are reasonably predictable, and related resource challenges are quite visible. The world's population is expected to grow to around 8 billion by 2025. According to the International Food Policy Research Institute, if current levels of investments in agriculture and social welfare continue, food grain production will increase by about 1.5% and livestock production by 2.7% a year over the next 2 decades. These levels are much lower now compared to previous decades, and population could outstrip supply unless there is a big increase in developing country imports. The continued destruction of the earth's forest mantle as a result of human activities is another desperate concern. By 2025, some 3 billion people will live in land-short countries and another 2 billion will be living in urban areas with high levels of air pollution. In addition, coastal ecosystems, which are already exposed to unbridled coastal development and mounting pollution loads, will experience more pressures as the number of people living near them increases in the next 25 years. One final challenge is the unprecedented rate of habitat loss and species extinction. Ecosystem destruction is so severe that as many as 60,000 plant species could be lost by the year 2025.

  7. MMap: Fast Billion-Scale Graph Computation on a PC via Memory Mapping

    PubMed Central

    Lin, Zhiyuan; Kahng, Minsuk; Sabrin, Kaeser Md.; Chau, Duen Horng (Polo); Lee, Ho; Kang, U

    2015-01-01

    Graph computation approaches such as GraphChi and TurboGraph recently demonstrated that a single PC can perform efficient computation on billion-node graphs. To achieve high speed and scalability, they often need sophisticated data structures and memory management strategies. We propose a minimalist approach that forgoes such requirements, by leveraging the fundamental memory mapping (MMap) capability found on operating systems. We contribute: (1) a new insight that MMap is a viable technique for creating fast and scalable graph algorithms that surpasses some of the best techniques; (2) the design and implementation of popular graph algorithms for billion-scale graphs with little code, thanks to memory mapping; (3) extensive experiments on real graphs, including the 6.6 billion edge YahooWeb graph, and show that this new approach is significantly faster or comparable to the highly-optimized methods (e.g., 9.5× faster than GraphChi for computing PageRank on 1.47B edge Twitter graph). We believe our work provides a new direction in the design and development of scalable algorithms. Our packaged code is available at http://poloclub.gatech.edu/mmap/. PMID:25866846

  8. Severe Obesity In Adults Cost State Medicaid Programs Nearly $8 Billion In 2013.

    PubMed

    Wang, Y Claire; Pamplin, John; Long, Michael W; Ward, Zachary J; Gortmaker, Steven L; Andreyeva, Tatiana

    2015-11-01

    Efforts to expand Medicaid while controlling spending must be informed by a deeper understanding of the extent to which the high medical costs associated with severe obesity (having a body mass index of [Formula: see text] or higher) determine spending at the state level. Our analysis of population-representative data indicates that in 2013, severe obesity cost the nation approximately $69 billion, which accounted for 60 percent of total obesity-related costs. Approximately 11 percent of the cost of severe obesity was paid for by Medicaid, 30 percent by Medicare and other federal health programs, 27 percent by private health plans, and 30 percent out of pocket. Overall, severe obesity cost state Medicaid programs almost $8 billion a year, ranging from $5 million in Wyoming to $1.3 billion in California. These costs are likely to increase following Medicaid expansion and enhanced coverage of weight loss therapies in the form of nutrition consultation, drug therapy, and bariatric surgery. Ensuring and expanding Medicaid-eligible populations' access to cost-effective treatment for severe obesity should be part of each state's strategy to mitigate rising obesity-related health care costs.

  9. LLNL's Big Science Capabilities Help Spur Over $796 Billion in U.S. Economic Activity Sequencing the Human Genome

    SciTech Connect

    Stewart, Jeffrey S.

    2015-07-28

    LLNL’s successful history of taking on big science projects spans beyond national security and has helped create billions of dollars per year in new economic activity. One example is LLNL’s role in helping sequence the human genome. Over $796 billion in new economic activity in over half a dozen fields has been documented since LLNL successfully completed this Grand Challenge.

  10. Braking formula for electrons of relativistic speed

    NASA Astrophysics Data System (ADS)

    Bethe, H.; Bartschat, Klaus

    2014-12-01

    The current translation is by Klaus Bartschat, Department of Physics and Astronomy, Drake University, Des Moines, Iowa 50311, USA. An attempt has been made to preserve Bethe's writing style as much as possible, including his use of "Volt" instead of "electron volt". Even though the term "stopping power" is quite common in present scientific English, we generally use "braking [capability]" rather than "stopping [power]", in order to emphasize the act [and ability] of slowing down the particle rather than the ultimate result of bringing it to a complete halt. Also, a few typographical errors were kept in the English translation to ensure the translation replicates the original paper. Please, see Section 3 of the annotation to Bethe's article [Fontes, C.J., Bostock, C.J. and Bartschat, K. 2014. Eur. Phys. J. H, 39: 517-536] for a list. The references were converted to EPJH style, and the footnotes are numbered consecutively.

  11. Mobile hydrocarbon microspheres from >2-billion-year-old carbon-bearing seams in the South African deep subsurface.

    PubMed

    Wanger, G; Moser, D; Hay, M; Myneni, S; Onstott, T C; Southam, G

    2012-11-01

    By ~2.9 Ga, the time of the deposition of the Witwatersrand Supergroup, life is believed to have been well established on Earth. Carbon remnants of the microbial biosphere from this time period are evident in sediments from around the world. In the Witwatersrand Supergroup, the carbonaceous material is often concentrated in seams, closely associated with the gold deposits and may have been a mobile phase 2 billion years ago. Whereas today the carbon in the Witwatersrand Supergroup is presumed to be immobile, hollow hydrocarbon spheres ranging in size from <1 μm to >50 μm were discovered emanating from a borehole drilled through the carbon-bearing seams suggesting that a portion of the carbon may still be mobile in the deep subsurface. ToF-SIMS and STXM analyses revealed that these spheres contain a suite of alkane, alkenes, and aromatic compounds consistent with the described organic-rich carbon seams within the Witwatersrand Supergroup's auriferous reef horizons. Analysis by electron microscopy and ToF-SIMS, however, revealed that these spheres, although most likely composed of biogenic carbon and resembling biological organisms, do not retain any true structural, that is, fossil, information and were formed by an abiogenic process.

  12. A 17-billion-solar-mass black hole in a group galaxy with a diffuse core

    NASA Astrophysics Data System (ADS)

    Thomas, Jens; Ma, Chung-Pei; McConnell, Nicholas J.; Greene, Jenny E.; Blakeslee, John P.; Janish, Ryan

    2016-04-01

    Quasars are associated with and powered by the accretion of material onto massive black holes; the detection of highly luminous quasars with redshifts greater than z = 6 suggests that black holes of up to ten billion solar masses already existed 13 billion years ago. Two possible present-day ‘dormant’ descendants of this population of ‘active’ black holes have been found in the galaxies NGC 3842 and NGC 4889 at the centres of the Leo and Coma galaxy clusters, which together form the central region of the Great Wall—the largest local structure of galaxies. The most luminous quasars, however, are not confined to such high-density regions of the early Universe; yet dormant black holes of this high mass have not yet been found outside of modern-day rich clusters. Here we report observations of the stellar velocity distribution in the galaxy NGC 1600—a relatively isolated elliptical galaxy near the centre of a galaxy group at a distance of 64 megaparsecs from Earth. We use orbit superposition models to determine that the black hole at the centre of NGC 1600 has a mass of 17 billion solar masses. The spatial distribution of stars near the centre of NGC 1600 is rather diffuse. We find that the region of depleted stellar density in the cores of massive elliptical galaxies extends over the same radius as the gravitational sphere of influence of the central black holes, and interpret this as the dynamical imprint of the black holes.

  13. The First Billion Years: The Growth of Galaxies in the Reionization Epoch

    NASA Astrophysics Data System (ADS)

    Illingworth, Garth

    2015-08-01

    Detection and measurement of the earliest galaxies in the first billion years only became possible after the Hubble Space Telescope was updated in 2009 with the infrared WFC3/IR camera during Shuttle servicing mission SM4. The first billion years is a fascinating epoch, not just because of the earliest galaxies known from about 450 Myr after the Big Bang, but also because it encompasses the reionization epoch that peaked around z~9, as Planck has recently shown, and ended around redshift z~6 at 900 Myr. Before 2009 just a handful of galaxies were known in the reionization epoch at z>6. But within the last 5 years, with the first HUDF09 survey, the HUDF12, CANDELS and numerous other surveys on the GOODS and CANDELS fields, as well as detections from the cluster lensing programs like CLASH and the Frontier Fields, the number of galaxies at redshifts 7-10 has exploded, with some 700 galaxies being found and characterized. The first billion years was a period of extraordinary growth in the galaxy population with rapid growth in the star formation rate density and global mass density in galaxies. Spitzer observations in the infrared of these Hubble fields are establishing masses as well as giving insights into the nature and timescales of star formation from the very powerful emission lines being revealed by the Spitzer IRAC data. I will discuss what we understand about the growth of galaxies in this epoch from the insights gained from remarkable deep fields like the XDF, as well as the wide-area GOODS/CANDELS fields, the detection of unexpectedly luminous galaxies at redshifts 8-10, the impact of early galaxies on reionization, confirmation of a number of galaxies at z~7-8 from ground-based spectroscopic measurements, and the indications of a change in the growth of the star formation rate around 500 Myr. The first billion years was a time of dramatic growth and change in the early galaxy population.

  14. The $1. 5 billion question: Can the US Global Change Research Program deliver on its promises

    SciTech Connect

    Monastersky, R.

    1993-09-04

    President Clinton has continued the funding for scientific investigations of global climatic change, increasing funds to a total of $1.5 billion spread amoung 11 different agencies. However, a growing number of critics warn that the program appears heading toward failure. The main issue is relevancy. Almost every agrees that the research effort will support important scientific work over the next decade, but it will not necessarily provide the information policymakers need to address the threat of climatic change, ozone depletion, deforestation, desertification, and similiar issues. This article summarizes the concerns and comments of critics, and the gap between the climate scientists and governmental policymakers.

  15. Exploring for Galaxies in the First Billion Years with Hubble and Spitzer - Pathfinding for JWST

    NASA Astrophysics Data System (ADS)

    Illingworth, Garth D.

    2017-01-01

    Hubble has revolutionized the field of distant galaxies through its deep imaging surveys, starting with the Hubble Deep Field (HDF) in 1995. That first deep survey revealed galaxies at redshift z~1-3 that provided insights into the development of the Hubble sequence. Each new HST instrument has explored new regimes, through the peak of star formation at z~2-3, just 2-3 billion years after the Big Bang, to our first datasets at a billion years at z~6, and then earlier to z~11. HST's survey capabilities were enhanced by 40X with ACS, and then similarly with the WFC3/IR, which opened up the first billion years to an unforeseen degree. I will discuss what we have learned from the remarkable HST and Spitzer imaging surveys (HUDF, GOODS, HUDF09/12 and CANDELS), as well as surveys of clusters like the Hubble Frontier Fields (HFF). Lensing clusters provide extraordinary opportunities for characterizing the faintest earliest galaxies, but also present extraordinary challenges. Together these surveys have resulted in the measurement of the volume density of galaxies in the first billion years down to astonishingly faint levels. The role of faint galaxies in reionizing the universe is still much-discussed, but there is no doubt that such galaxies contribute greatly to the UV ionizing flux, as shown by deep luminosity function studies. Together Hubble and Spitzer have also established the stellar-mass buildup over 97% of cosmic history. Yet some of the greatest surprises have come from the discovery of very luminous galaxies at z~8-11, around 400-650 million years after the Big Bang. Spectroscopic followup by Keck of some of these very rare, bright galaxies has confirmed redshifts from z~7 to z~9, and revealed, surprisingly, strong Lyα emission near the peak of reionization when the HI fraction in the IGM is high. The recent confirmation of a z=11.1 galaxy, just 400 million years after the Big Bang, by a combination of Hubble and Spitzer data, moved Hubble into JWST territory

  16. Dynamics of chemical bonding mapped by energy-resolved 4D electron microscopy.

    PubMed

    Carbone, Fabrizio; Kwon, Oh-Hoon; Zewail, Ahmed H

    2009-07-10

    Chemical bonding dynamics are fundamental to the understanding of properties and behavior of materials and molecules. Here, we demonstrate the potential of time-resolved, femtosecond electron energy loss spectroscopy (EELS) for mapping electronic structural changes in the course of nuclear motions. For graphite, it is found that changes of milli-electron volts in the energy range of up to 50 electron volts reveal the compression and expansion of layers on the subpicometer scale (for surface and bulk atoms). These nonequilibrium structural features are correlated with the direction of change from sp2 [two-dimensional (2D) graphene] to sp3 (3D-diamond) electronic hybridization, and the results are compared with theoretical charge-density calculations. The reported femtosecond time resolution of four-dimensional (4D) electron microscopy represents an advance of 10 orders of magnitude over that of conventional EELS methods.

  17. A massive galaxy in its core formation phase three billion years after the Big Bang.

    PubMed

    Nelson, Erica; van Dokkum, Pieter; Franx, Marijn; Brammer, Gabriel; Momcheva, Ivelina; Schreiber, Natascha Förster; da Cunha, Elisabete; Tacconi, Linda; Bezanson, Rachel; Kirkpatrick, Allison; Leja, Joel; Rix, Hans-Walter; Skelton, Rosalind; van der Wel, Arjen; Whitaker, Katherine; Wuyts, Stijn

    2014-09-18

    Most massive galaxies are thought to have formed their dense stellar cores in early cosmic epochs. Previous studies have found galaxies with high gas velocity dispersions or small apparent sizes, but so far no objects have been identified with both the stellar structure and the gas dynamics of a forming core. Here we report a candidate core in the process of formation 11 billion years ago, at redshift z = 2.3. This galaxy, GOODS-N-774, has a stellar mass of 100 billion solar masses, a half-light radius of 1.0 kiloparsecs and a star formation rate of solar masses per year. The star-forming gas has a velocity dispersion of 317 ± 30 kilometres per second. This is similar to the stellar velocity dispersions of the putative descendants of GOODS-N-774, which are compact quiescent galaxies at z ≈ 2 (refs 8-11) and giant elliptical galaxies in the nearby Universe. Galaxies such as GOODS-N-774 seem to be rare; however, from the star formation rate and size of this galaxy we infer that many star-forming cores may be heavily obscured, and could be missed in optical and near-infrared surveys.

  18. Greenhouse gas implications of a 32 billion gallon bioenergy landscape in the US

    NASA Astrophysics Data System (ADS)

    DeLucia, E. H.; Hudiburg, T. W.; Wang, W.; Khanna, M.; Long, S.; Dwivedi, P.; Parton, W. J.; Hartman, M. D.

    2015-12-01

    Sustainable bioenergy for transportation fuel and greenhouse gas (GHGs) reductions may require considerable changes in land use. Perennial grasses have been proposed because of their potential to yield substantial biomass on marginal lands without displacing food and reduce GHG emissions by storing soil carbon. Here, we implemented an integrated approach to planning bioenergy landscapes by combining spatially-explicit ecosystem and economic models to predict a least-cost land allocation for a 32 billion gallon (121 billion liter) renewable fuel mandate in the US. We find that 2022 GHG transportation emissions are decreased by 7% when 3.9 million hectares of eastern US land are converted to perennial grasses supplemented with corn residue to meet cellulosic ethanol requirements, largely because of gasoline displacement and soil carbon storage. If renewable fuel production is accompanied by a cellulosic biofuel tax credit, CO2 equivalent emissions could be reduced by 12%, because it induces more cellulosic biofuel and land under perennial grasses (10 million hectares) than under the mandate alone. While GHG reducing bioenergy landscapes that meet RFS requirements and do not displace food are possible, the reductions in GHG emissions are 50% less compared to previous estimates that did not account for economically feasible land allocation.

  19. On the constancy of the lunar cratering flux over the past 3.3 billion yr

    NASA Technical Reports Server (NTRS)

    Guinness, E. A.; Arvidson, R. E.

    1977-01-01

    Utilizing a method that minimizes random fluctuations in sampling crater populations, it can be shown that the ejecta deposit of Tycho, the floor of Copernicus, and the region surrounding the Apollo 12 landing site have incremental crater size-frequency distributions that can be expressed as log-log linear functions over the diameter range from 0.1 to 1 km. Slopes are indistinguishable for the three populations, probably indicating that the surfaces are dominated by primary craters. Treating the crater populations of Tycho, the floor of Copernicus, and Apollo 12 as primary crater populations contaminated, but not overwhelmed, with secondaries, allows an attempt at calibration of the post-heavy bombardment cratering flux. Using the age of Tycho as 109 m.y., Copernicus as 800 m.y., and Apollo 12 as 3.26 billion yr, there is no basis for assuming that the flux has changed over the past 3.3 billion yr. This result can be used for dating intermediate aged surfaces by crater density.

  20. Energy tax price tag for CPI: $1. 2 billion, jobs, and production

    SciTech Connect

    Begley, R.

    1993-03-03

    If President Clinton's proposed energy tax had been fully in place last year, it would have cost the US chemical industry an additional $1.2 billion and 9,900 jobs, according to Chemical Manufacturers Association (CMA; Washington) estimates. It also would have driven output down 3% and prices up 5%, CMA says. Allen Lenz, CMA director/trade and economics, says the increase in production costs that would accompany the tax will not be shared by foreign competitors, cannot be neutralized with higher border taxes because of existing trade agreements, and provides another reason to move production offshore. Worse, the US chemical industry's generally impressive trade surplus declined by $2.5 billion last year, and a further drop is projected for this year. The margin of error gets thinner all the time as competition increases, Lenz says. We're not concerned only with the chemical industry, but the rest of US-based manufacturing because they taken half our output, he adds. One problem is the energy intensiveness of the chemical process industries-a CMA report says that 55% of the cost of producing ethylene glycol is energy related. And double taxation of such things as coproducts returned for credit to oil refineries could add up to $115 million/year, the report says.

  1. The Value Of The Nonprofit Hospital Tax Exemption Was $24.6 Billion In 2011.

    PubMed

    Rosenbaum, Sara; Kindig, David A; Bao, Jie; Byrnes, Maureen K; O'Laughlin, Colin

    2015-07-01

    The federal government encourages public support for charitable activities by allowing people to deduct donations to tax-exempt organizations on their income tax returns. Tax-exempt hospitals are major beneficiaries of this policy because it encourages donations to the hospitals while shielding them from federal and state tax liability. In exchange, these hospitals must engage in community benefit activities, such as providing care to indigent patients and participating in Medicaid. The congressional Joint Committee on Taxation estimated the value of the nonprofit hospital tax exemption at $12.6 billion in 2002--a number that included forgone taxes, public contributions, and the value of tax-exempt bond financing. In this article we estimate that the size of the exemption reached $24.6 billion in 2011. The Affordable Care Act (ACA) brings a new focus on community benefit activities by requiring tax-exempt hospitals to engage in communitywide planning efforts to improve community health. The magnitude of the tax exemption, coupled with ACA reforms, underscores the public's interest not only in community benefit spending generally but also in the extent to which nonprofit hospitals allocate funds for community benefit expenditures that improve the overall health of their communities.

  2. Increased subaerial volcanism and the rise of atmospheric oxygen 2.5 billion years ago.

    PubMed

    Kump, Lee R; Barley, Mark E

    2007-08-30

    The hypothesis that the establishment of a permanently oxygenated atmosphere at the Archaean-Proterozoic transition (approximately 2.5 billion years ago) occurred when oxygen-producing cyanobacteria evolved is contradicted by biomarker evidence for their presence in rocks 200 million years older. To sustain vanishingly low oxygen levels despite near-modern rates of oxygen production from approximately 2.7-2.5 billion years ago thus requires that oxygen sinks must have been much larger than they are now. Here we propose that the rise of atmospheric oxygen occurred because the predominant sink for oxygen in the Archaean era-enhanced submarine volcanism-was abruptly and permanently diminished during the Archaean-Proterozoic transition. Observations are consistent with the corollary that subaerial volcanism only became widespread after a major tectonic episode of continental stabilization at the beginning of the Proterozoic. Submarine volcanoes are more reducing than subaerial volcanoes, so a shift from predominantly submarine to a mix of subaerial and submarine volcanism more similar to that observed today would have reduced the overall sink for oxygen and led to the rise of atmospheric oxygen.

  3. The evolution in the stellar mass of brightest cluster galaxies over the past 10 billion years

    NASA Astrophysics Data System (ADS)

    Bellstedt, Sabine; Lidman, Chris; Muzzin, Adam; Franx, Marijn; Guatelli, Susanna; Hill, Allison R.; Hoekstra, Henk; Kurinsky, Noah; Labbe, Ivo; Marchesini, Danilo; Marsan, Z. Cemile; Safavi-Naeini, Mitra; Sifón, Cristóbal; Stefanon, Mauro; van de Sande, Jesse; van Dokkum, Pieter; Weigel, Catherine

    2016-08-01

    Using a sample of 98 galaxy clusters recently imaged in the near-infrared with the European Southern Observatory (ESO) New Technology Telescope, WIYN telescope and William Herschel Telescope, supplemented with 33 clusters from the ESO archive, we measure how the stellar mass of the most massive galaxies in the universe, namely brightest cluster galaxies (BCGs), increases with time. Most of the BCGs in this new sample lie in the redshift range 0.2 < z < 0.6, which has been noted in recent works to mark an epoch over which the growth in the stellar mass of BCGs stalls. From this sample of 132 clusters, we create a subsample of 102 systems that includes only those clusters that have estimates of the cluster mass. We combine the BCGs in this subsample with BCGs from the literature, and find that the growth in stellar mass of BCGs from 10 billion years ago to the present epoch is broadly consistent with recent semi-analytic and semi-empirical models. As in other recent studies, tentative evidence indicates that the stellar mass growth rate of BCGs may be slowing in the past 3.5 billion years. Further work in collecting larger samples, and in better comparing observations with theory using mock images, is required if a more detailed comparison between the models and the data is to be made.

  4. Parametrization and Classification of 20 Billion LSST Objects: Lessons from SDSS

    SciTech Connect

    Ivezic, Z.; Axelrod, T.; Becker, A.C.; Becla, J.; Borne, K.; Burke, David L.; Claver, C.F.; Cook, K.H.; Connolly, A.; Gilmore, D.K.; Jones, R.L.; Juric, M.; Kahn, Steven M.; Lim, K-T.; Lupton, R.H.; Monet, D.G.; Pinto, P.A.; Sesar, B.; Stubbs, Christopher W.; Tyson, J.Anthony; /UC, Davis

    2011-11-10

    The Large Synoptic Survey Telescope (LSST) will be a large, wide-field ground-based system designed to obtain, starting in 2015, multiple images of the sky that is visible from Cerro Pachon in Northern Chile. About 90% of the observing time will be devoted to a deep-wide-fast survey mode which will observe a 20,000 deg{sup 2} region about 1000 times during the anticipated 10 years of operations (distributed over six bands, ugrizy). Each 30-second long visit will deliver 5{sigma} depth for point sources of r {approx} 24.5 on average. The co-added map will be about 3 magnitudes deeper, and will include 10 billion galaxies and a similar number of stars. We discuss various measurements that will be automatically performed for these 20 billion sources, and how they can be used for classification and determination of source physical and other properties. We provide a few classification examples based on SDSS data, such as color classification of stars, color-spatial proximity search for wide-angle binary stars, orbital-color classification of asteroid families, and the recognition of main Galaxy components based on the distribution of stars in the position-metallicity-kinematics space. Guided by these examples, we anticipate that two grand classification challenges for LSST will be (1) rapid and robust classification of sources detected in difference images, and (2) simultaneous treatment of diverse astrometric and photometric time series measurements for an unprecedentedly large number of objects.

  5. A stimulating conversation. Healthcare organizations praise the economic stimulus law, start considering ways to use the $150 billion in relief.

    PubMed

    Lubell, Jennifer

    2009-02-23

    The industry eagerly awaits its $150 billion under the stimulus package, but not everyone will win, experts say. Still, "The initial stimulus package was a very solid start," said system exec Conway Collis, left.

  6. SESAM: exploring the frontiers of electron microscopy.

    PubMed

    Koch, Christoph T; Sigle, Wilfried; Höschen, Rainer; Rühle, Manfred; Essers, Erik; Benner, Gerd; Matijevic, Marko

    2006-12-01

    We report on the sub-electron-volt-sub-angstrom microscope (SESAM), a high-resolution 200-kV FEG-TEM equipped with a monochromator and an in-column MANDOLINE filter. We report on recent results obtained with this instrument, demonstrating its performance (e.g., 87-meV energy resolution at 10-s exposure time, or a transmissivity of the energy filter of T1 ev = 11,000 nm2). New opportunities to do unique experiments that may advance the frontiers of microscopy in areas such as energy-filtered TEM, spectroscopy, energy-filtered electron diffraction and spectroscopic profiling are also discussed.

  7. Evidence for Early Life in ˜3.5 Billion-Year-Old Pillow Lavas

    NASA Astrophysics Data System (ADS)

    Banerjee, N. R.; Furnes, H.; Muehlenbachs, K.; Staudigel, H.; de Wit, M.

    2004-12-01

    Recently discovered biosignatures in the formerly glassy rims of ˜3.5 billion-year-old pillow lavas from the Barberton Greenstone Belt (BGB) in South Africa suggest they were colonized by microbes early in Earth's history. These subaqueous volcanic rocks represent a new geological setting in the search for early life on Earth. This is not entirely surprising since microbial alteration of basaltic glass in pillow lavas and volcaniclastic rocks has been well documented from recent oceanic crust and well-preserved ophiolites. The BGB magmatic sequence contains exceptionally well-preserved mafic to ultramafic pillow lavas, sheet flows, and intrusions interpreted to represent 3.48 to 3.22 billion-year-old oceanic crust and island arc assemblages. We observed micron-sized tubular structures mineralized by titanite in the formerly glassy rims of the BGB pillow lavas. Based on their similarity to textures observed in recent glassy pillow basalts we interpret these structures to represent ancient traces of microbial activity formed during biogenic etching of the originally glassy pillow rims as microbes colonized the glass surface. Petrographic observations coupled with overlapping metamorphic and magmatic dates indicate this process occurred soon after eruption of the pillow lavas. Subsequent greenschist facies seafloor hydrothermal alteration caused the structures to be mineralized by titanite; a process also observed in ophiolitic pillow lavas of much younger age. X-ray mapping reveals the presence of carbon along the margins of the tubular structures interpreted as residual organic material. Disseminated carbonates within the microbially-altered BGB pillow rims have low carbon isotope values consistent with microbial oxidation of organic matter. In contrast, disseminated carbonate in the crystalline pillow interiors have carbon isotope values bracketed between Archean marine carbonate and mantle carbon dioxide. It remains to be seen how deep into the Archean oceanic

  8. Electron deposition in water vapor, with atmospheric applications.

    NASA Technical Reports Server (NTRS)

    Olivero, J. J.; Stagat, R. W.; Green, A. E. S.

    1972-01-01

    Examination of the consequences of electron impact on water vapor in terms of the microscopic details of excitation, dissociation, ionization, and combinations of these processes. Basic electron-impact cross-section data are assembled in many forms and are incorporated into semianalytic functions suitable for analysis with digital computers. Energy deposition in water vapor is discussed, and the energy loss function is presented, along with the 'electron volts per ion pair' and the efficiencies of energy loss in various processes. Several applications of electron and water-vapor interactions in the atmospheric sciences are considered, in particular, H2O comets, aurora and airglow, and lightning.

  9. The VIRMOS-VLT Deep Survey: the Last 10 Billion Years of Evolution of Galaxy Clustering

    NASA Astrophysics Data System (ADS)

    Pollo, A.; Guzzo, L.; Le Fèvre, O.; Meneux, B.; Cappi, A.; McCracken, H. J.; Iovino, A.; Marinoni, C.; Bottini, D.; Garilli, B.; Le Brun, V. L.; Maccagni, D.; Picat, J. P.; Scaramella, R.; Scodeggio, M.; Tresse, L.; Vettolani, G.; Zanichelli, A.; Adami, C.; Arnouts, S.; Bardelli, S.; Bolzonella, M.; Charlot, S.; Ciliegi, P.; Contini, T.; Foucaud, S.; Franzetti, P.; Gavignaud, I.; Ilbert, O.; Marano, B.; Mazure, A.; Merighi, R.; Paltani, S.; Pellò, R.; Pozzetti, L.; Radovich, M.; Zamorani, G.; Zucca, E.; Bondi, M.; Bongiorno, A.; Brinchmann, J.; Cucciati, O.; de la Torre, S.; Lamareille, F.; Mellier, Y.; Merluzzi, P.; Temporin, S.; Vergani, D.; Walcher, C. J.

    2007-12-01

    We discuss the evolution of clustering of galaxies in the Universe from the present epoch back to z ˜ 2, using the first-epoch data from the VIMOS-VLT Deep Survey (VVDS). We present the evolution of the projected two-point correlation function of galaxies for the global galaxy population, as well as its dependence on galaxy intrinsic luminosities and spectral types. While we do not find strong variations of the correlation function parameters with redshift for the global galaxy population, the clustering of objects with different intrinsic luminosities evolved significantly during last 8-10 billion years. Our findings indicate that bright galaxies in the past traced higher density peaks than they do now and that the shape of the correlation function of most luminous galaxies is different from observed for their local counterparts, which is a supporting evidence of a non-trivial evolution of the galaxy vs. dark matter bias.

  10. Collision-free spatial hash functions for structural analysis of billion-vertex chemical bond networks

    NASA Astrophysics Data System (ADS)

    Zhang, Cheng; Bansal, Bhupesh; Branicio, Paulo S.; Kalia, Rajiv K.; Nakano, Aiichiro; Sharma, Ashish; Vashishta, Priya

    2006-09-01

    State-of-the-art molecular dynamics (MD) simulations generate massive datasets involving billion-vertex chemical bond networks, which makes data mining based on graph algorithms such as K-ring analysis a challenge. This paper proposes an algorithm to improve the efficiency of ring analysis of large graphs, exploiting properties of K-rings and spatial correlations of vertices in the graph. The algorithm uses dual-tree expansion (DTE) and spatial hash-function tagging (SHAFT) to optimize computation and memory access. Numerical tests show nearly perfect linear scaling of the algorithm. Also a parallel implementation of the DTE + SHAFT algorithm achieves high scalability. The algorithm has been successfully employed to analyze large MD simulations involving up to 500 million atoms.

  11. Enumeration of 166 billion organic small molecules in the chemical universe database GDB-17.

    PubMed

    Ruddigkeit, Lars; van Deursen, Ruud; Blum, Lorenz C; Reymond, Jean-Louis

    2012-11-26

    Drug molecules consist of a few tens of atoms connected by covalent bonds. How many such molecules are possible in total and what is their structure? This question is of pressing interest in medicinal chemistry to help solve the problems of drug potency, selectivity, and toxicity and reduce attrition rates by pointing to new molecular series. To better define the unknown chemical space, we have enumerated 166.4 billion molecules of up to 17 atoms of C, N, O, S, and halogens forming the chemical universe database GDB-17, covering a size range containing many drugs and typical for lead compounds. GDB-17 contains millions of isomers of known drugs, including analogs with high shape similarity to the parent drug. Compared to known molecules in PubChem, GDB-17 molecules are much richer in nonaromatic heterocycles, quaternary centers, and stereoisomers, densely populate the third dimension in shape space, and represent many more scaffold types.

  12. Geodynamo, solar wind, and magnetopause 3.4 to 3.45 billion years ago.

    PubMed

    Tarduno, John A; Cottrell, Rory D; Watkeys, Michael K; Hofmann, Axel; Doubrovine, Pavel V; Mamajek, Eric E; Liu, Dunji; Sibeck, David G; Neukirch, Levi P; Usui, Yoichi

    2010-03-05

    Stellar wind standoff by a planetary magnetic field prevents atmospheric erosion and water loss. Although the early Earth retained its water and atmosphere, and thus evolved as a habitable planet, little is known about Earth's magnetic field strength during that time. We report paleointensity results from single silicate crystals bearing magnetic inclusions that record a geodynamo 3.4 to 3.45 billion years ago. The measured field strength is approximately 50 to 70% that of the present-day field. When combined with a greater Paleoarchean solar wind pressure, the paleofield strength data suggest steady-state magnetopause standoff distances of < or = 5 Earth radii, similar to values observed during recent coronal mass ejection events. The data also suggest lower-latitude aurora and increases in polar cap area, as well as heating, expansion, and volatile loss from the exosphere that would have affected long-term atmospheric composition.

  13. Early formation of the Moon 4.51 billion years ago

    PubMed Central

    Barboni, Melanie; Boehnke, Patrick; Keller, Brenhin; Kohl, Issaku E.; Schoene, Blair; Young, Edward D.; McKeegan, Kevin D.

    2017-01-01

    Establishing the age of the Moon is critical to understanding solar system evolution and the formation of rocky planets, including Earth. However, despite its importance, the age of the Moon has never been accurately determined. We present uranium-lead dating of Apollo 14 zircon fragments that yield highly precise, concordant ages, demonstrating that they are robust against postcrystallization isotopic disturbances. Hafnium isotopic analyses of the same fragments show extremely low initial 176Hf/177Hf ratios corrected for cosmic ray exposure that are near the solar system initial value. Our data indicate differentiation of the lunar crust by 4.51 billion years, indicating the formation of the Moon within the first ~60 million years after the birth of the solar system. PMID:28097222

  14. Investigation of Radar Propagation in Buildings: A 10 Billion Element Cartesian-Mesh FETD Simulation

    SciTech Connect

    Stowell, M L; Fasenfest, B J; White, D A

    2008-01-14

    In this paper large scale full-wave simulations are performed to investigate radar wave propagation inside buildings. In principle, a radar system combined with sophisticated numerical methods for inverse problems can be used to determine the internal structure of a building. The composition of the walls (cinder block, re-bar) may effect the propagation of the radar waves in a complicated manner. In order to provide a benchmark solution of radar propagation in buildings, including the effects of typical cinder block and re-bar, we performed large scale full wave simulations using a Finite Element Time Domain (FETD) method. This particular FETD implementation is tuned for the special case of an orthogonal Cartesian mesh and hence resembles FDTD in accuracy and efficiency. The method was implemented on a general-purpose massively parallel computer. In this paper we briefly describe the radar propagation problem, the FETD implementation, and we present results of simulations that used over 10 billion elements.

  15. Billion-atom synchronous parallel kinetic Monte Carlo simulations of critical 3D Ising systems

    SciTech Connect

    Martinez, E.; Monasterio, P.R.; Marian, J.

    2011-02-20

    An extension of the synchronous parallel kinetic Monte Carlo (spkMC) algorithm developed by Martinez et al. [J. Comp. Phys. 227 (2008) 3804] to discrete lattices is presented. The method solves the master equation synchronously by recourse to null events that keep all processors' time clocks current in a global sense. Boundary conflicts are resolved by adopting a chessboard decomposition into non-interacting sublattices. We find that the bias introduced by the spatial correlations attendant to the sublattice decomposition is within the standard deviation of serial calculations, which confirms the statistical validity of our algorithm. We have analyzed the parallel efficiency of spkMC and find that it scales consistently with problem size and sublattice partition. We apply the method to the calculation of scale-dependent critical exponents in billion-atom 3D Ising systems, with very good agreement with state-of-the-art multispin simulations.

  16. Extraterrestrial demise of banded iron formations 1.85 billion years ago

    USGS Publications Warehouse

    Slack, J.F.; Cannon, W.F.

    2009-01-01

    In the Lake Superior region of North America, deposition of most banded iron formations (BIFs) ended abruptly 1.85 Ga ago, coincident with the oceanic impact of the giant Sudbury extraterrestrial bolide. We propose a new model in which this impact produced global mixing of shallow oxic and deep anoxic waters of the Paleoproterozoic ocean, creating a suboxic redox state for deep seawater. This suboxic state, characterized by only small concentrations of dissolved O2 (???1 ??M), prevented transport of hydrothermally derived Fe(II) from the deep ocean to continental-margin settings, ending an ???1.1 billion-year-long period of episodic BIF mineralization. The model is supported by the nature of Precambrian deep-water exhalative chemical sediments, which changed from predominantly sulfide facies prior to ca. 1.85 Ga to mainly oxide facies thereafter. ?? 2009 Geological Society of America.

  17. Barium fluoride whispering-gallery-mode disk-resonator with one billion quality-factor.

    PubMed

    Lin, Guoping; Diallo, Souleymane; Henriet, Rémi; Jacquot, Maxime; Chembo, Yanne K

    2014-10-15

    We demonstrate a monolithic optical whispering-gallery-mode resonator fabricated with barium fluoride (BaF₂) with an ultra-high quality (Q) factor above 10⁹ at 1550 nm, and measured with both the linewidth and cavity-ring-down methods. Vertical scanning optical profilometry shows that the root mean square surface roughness of 2 nm is achieved for our mm-size disk. To the best of our knowledge, we show for the first time that one billion Q-factor is achievable by precision polishing in relatively soft crystals with mohs hardness of 3. We show that complex thermo-optical dynamics can take place in these resonators. Beside usual applications in nonlinear optics and microwave photonics, high-energy particle scintillation detection utilizing monolithic BaF₂ resonators potentially becomes feasible.

  18. Star Formation in Galaxy Clusters Over the Past 10 Billion Years

    NASA Astrophysics Data System (ADS)

    Tran, Kim-Vy

    2012-01-01

    Galaxy clusters are the largest gravitationally bound systems in the universe and include the most massive galaxies in the universe; this makes galaxy clusters ideal laboratories for disentangling the nature versus nurture aspect of how galaxies evolve. Understanding how galaxies form and evolve in clusters continues to be a fundamental question in astronomy. The ages and assembly histories of galaxies in rich clusters test both stellar population models and hierarchical formation scenarios. Is star formation in cluster galaxies simply accelerated relative to their counterparts in the lower density field, or do cluster galaxies assemble their stars in a fundamentally different manner? To answer this question, I review multi-wavelength results on star formation in galaxy clusters from Coma to the most distant clusters yet discovered at look-back times of 10 billion years (z 2).

  19. Atmospheric carbon dioxide: a driver of photosynthetic eukaryote evolution for over a billion years?

    PubMed

    Beerling, David J

    2012-02-19

    Exciting evidence from diverse fields, including physiology, evolutionary biology, palaeontology, geosciences and molecular genetics, is providing an increasingly secure basis for robustly formulating and evaluating hypotheses concerning the role of atmospheric carbon dioxide (CO(2)) in the evolution of photosynthetic eukaryotes. Such studies span over a billion years of evolutionary change, from the origins of eukaryotic algae through to the evolution of our present-day terrestrial floras, and have relevance for plant and ecosystem responses to future global CO(2) increases. The papers in this issue reflect the breadth and depth of approaches being adopted to address this issue. They reveal new discoveries pointing to deep evidence for the role of CO(2) in shaping evolutionary changes in plants and ecosystems, and establish an exciting cross-disciplinary research agenda for uncovering new insights into feedbacks between biology and the Earth system.

  20. Constraining the last 7 billion years of galaxy evolution in semi-analytic models

    NASA Astrophysics Data System (ADS)

    Mutch, Simon J.; Poole, Gregory B.; Croton, Darren J.

    2013-01-01

    We investigate the ability of the Croton et al. semi-analytic model to reproduce the evolution of observed galaxies across the final 7 billion years of cosmic history. Using Monte Carlo Markov Chain techniques we explore the available parameter space to produce a model which attempts to achieve a statistically accurate fit to the observed stellar mass function at z = 0 and z ≈ 0.8, as well as the local black hole-bulge relation. We find that in order to be successful we are required to push supernova feedback efficiencies to extreme limits which are, in some cases, unjustified by current observations. This leads us to the conclusion that the current model may be incomplete. Using the posterior probability distributions provided by our fitting, as well as the qualitative details of our produced stellar mass functions, we suggest that any future model improvements must act to preferentially bolster star formation efficiency in the most massive haloes at high redshift.

  1. Atmospheric carbon dioxide: a driver of photosynthetic eukaryote evolution for over a billion years?

    PubMed Central

    Beerling, David J.

    2012-01-01

    Exciting evidence from diverse fields, including physiology, evolutionary biology, palaeontology, geosciences and molecular genetics, is providing an increasingly secure basis for robustly formulating and evaluating hypotheses concerning the role of atmospheric carbon dioxide (CO2) in the evolution of photosynthetic eukaryotes. Such studies span over a billion years of evolutionary change, from the origins of eukaryotic algae through to the evolution of our present-day terrestrial floras, and have relevance for plant and ecosystem responses to future global CO2 increases. The papers in this issue reflect the breadth and depth of approaches being adopted to address this issue. They reveal new discoveries pointing to deep evidence for the role of CO2 in shaping evolutionary changes in plants and ecosystems, and establish an exciting cross-disciplinary research agenda for uncovering new insights into feedbacks between biology and the Earth system. PMID:22232760

  2. Dust production 0.7-1.5 billion years after the Big Bang

    NASA Astrophysics Data System (ADS)

    Michałowski, Michał J.

    2016-06-01

    Cosmic dust is an important component of the Universe, and its origin, especially at high redshifts, is still unknown. I present a simple but powerful method of assessing whether dust observed in a given galaxy could in principle have been formed by asymptotic giant branch (AGB) stars or supernovae (SNe). Using this method I show that for most of the galaxies with detected dust emission between z=4 and z=7.5 (1.5-0.7 billion years after the Big Bang) AGB stars are not numerous and efficient enough to be responsible for the measured dust masses. Supernovae could account for most of the dust, but only if all of them had efficiencies close to the maximal theoretically allowed value. This suggests that a different mechanism is responsible for dust production at high redshifts, and the most likely possibility is the grain growth in the interstellar medium.

  3. U.S. Billion-Ton Update: Biomass Supply for a Bioenergy and Bioproducts Industry

    SciTech Connect

    Downing, Mark; Eaton, Laurence M; Graham, Robin Lambert; Langholtz, Matthew H; Perlack, Robert D; Turhollow Jr, Anthony F; Stokes, Bryce; Brandt, Craig C

    2011-08-01

    The report, Biomass as Feedstock for a Bioenergy and Bioproducts Industry: The Technical Feasibility of a Billion-Ton Annual Supply (generally referred to as the Billion-Ton Study or 2005 BTS), was an estimate of 'potential' biomass based on numerous assumptions about current and future inventory, production capacity, availability, and technology. The analysis was made to determine if conterminous U.S. agriculture and forestry resources had the capability to produce at least one billion dry tons of sustainable biomass annually to displace 30% or more of the nation's present petroleum consumption. An effort was made to use conservative estimates to assure confidence in having sufficient supply to reach the goal. The potential biomass was projected to be reasonably available around mid-century when large-scale biorefineries are likely to exist. The study emphasized primary sources of forest- and agriculture-derived biomass, such as logging residues, fuel treatment thinnings, crop residues, and perennially grown grasses and trees. These primary sources have the greatest potential to supply large, reliable, and sustainable quantities of biomass. While the primary sources were emphasized, estimates of secondary residue and tertiary waste resources of biomass were also provided. The original Billion-Ton Resource Assessment, published in 2005, was divided into two parts-forest-derived resources and agriculture-derived resources. The forest resources included residues produced during the harvesting of merchantable timber, forest residues, and small-diameter trees that could become available through initiatives to reduce fire hazards and improve forest health; forest residues from land conversion; fuelwood extracted from forests; residues generated at primary forest product processing mills; and urban wood wastes, municipal solid wastes (MSW), and construction and demolition (C&D) debris. For these forest resources, only residues, wastes, and small-diameter trees were

  4. Cooling and exhumation of continents at billion-year time scales

    NASA Astrophysics Data System (ADS)

    Blackburn, T.; Bowring, S. A.; Perron, T.; Mahan, K. H.; Dudas, F. O.

    2011-12-01

    The oldest rocks on Earth are preserved within the continental lithosphere, where assembled fragments of ancient orogenic belts have survived erosion and destruction by plate tectonic and surface processes for billions of years. Though the rate of orogenic exhumation and erosion has been measured for segments of an orogenic history, it remains unclear how these exhumation rates have changed over the lifetime of any terrane. Because the exhumation of the lithospheric surface has a direct effect on the rate of heat loss within the lithosphere, a continuous record of lithosphere exhumation can be reconstructed through the use of thermochronology. Thermochronologic studies have typically employed systems sensitive to cooling at temperatures <300 °C, such as the (U-Th)/He and 40Ar/39Ar systems. This largely restricts their application to measuring cooling in rocks from the outer 10 km of the Earth's crust, resulting in a thermal history that is controlled by either upper crustal flexure and faulting and/or isotherm inflections related to surface topography. Combining these biases with the uplift, erosion and recycling of these shallow rocks results in a poor preservation potential of any long-term record. Here, an ancient and long-term record of lithosphere exhumation is constructed using U-Pb thermochronology, a geochronologic system sensitive to cooling at temperatures found at 20-50 km depth (400-650 °C). Lower crustal xenoliths provide material that resided at these depths for billions of years or more, recording a thermal history that is buried deep enough to remain insensitive to upper crustal deformation and instead is dominated by the vertical motions of the continents. We show how this temperature-sensitive system can produce a long-term integrated measure of continental exhumation and erosion. Preserved beneath Phanerozoic sedimentary rocks within Montana, USA, the Great Falls Tectonic Zone formed when two Archean cratons, the Wyoming Province and Medicine

  5. A redox-stratified ocean 3.2 billion years ago

    NASA Astrophysics Data System (ADS)

    Satkoski, Aaron M.; Beukes, Nicolas J.; Li, Weiqiang; Beard, Brian L.; Johnson, Clark M.

    2015-11-01

    Before the Great Oxidation Event (GOE) 2.4-2.2 billion years ago it has been traditionally thought that oceanic water columns were uniformly anoxic due to a lack of oxygen-producing microorganisms. Recently, however, it has been proposed that transient oxygenation of shallow seawater occurred between 2.8 and 3.0 billion years ago. Here, we present a novel combination of stable Fe and radiogenic U-Th-Pb isotope data that demonstrate significant oxygen contents in the shallow oceans at 3.2 Ga, based on analysis of the Manzimnyama Banded Iron Formation (BIF), Fig Tree Group, South Africa. This unit is exceptional in that proximal, shallow-water and distal, deep-water facies are preserved. When compared to the distal, deep-water facies, the proximal samples show elevated U concentrations and moderately positive δ56Fe values, indicating vertical stratification in dissolved oxygen contents. Confirmation of oxidizing conditions using U abundances is robustly constrained using samples that have been closed to U and Pb mobility using U-Th-Pb geochronology. Although redox-sensitive elements have been commonly used in ancient rocks to infer redox conditions, post-depositional element mobility has been rarely tested, and U-Th-Pb geochronology can constrain open- or closed-system behavior. The U abundances and δ56Fe values of the Manzimnyama BIF suggest the proximal, shallow-water samples record precipitation under stronger oxidizing conditions compared to the distal deeper-water facies, which in turn indicates the existence of a discrete redox boundary between deep and shallow ocean waters at this time; this work, therefore, documents the oldest known preserved marine redox gradient in the rock record. The relative enrichment of O2 in the upper water column is likely due to the existence of oxygen-producing microorganisms such as cyanobacteria. These results provide a new approach for identifying free oxygen in Earth's ancient oceans, including confirming the age of redox

  6. Iapetus: 4.5 Billion Years of Contamination by Phoebe Dust

    NASA Astrophysics Data System (ADS)

    Hamilton, Douglas P.

    1997-07-01

    One of the strangest satellites in the Solar System is Saturn's tidally-locked Iapetus which has a bright white trailing hemisphere and a jet-black leading face. It has long been suspected that dark dusty debris, originating from Saturn's outermost satellite Phoebe and brought inward by Poynting-Robertson drag, is responsible for Iapetus' striking albedo asymmetry. The Phoebe-dust model is very compelling because it naturally explains why the leading face of Iapetus, the side that is receiving dust from Phoebe, is dark. The model has not gained universal acceptance, however, primarily due to the following dynamical problems: i) the distribution of dark material on Iapetus does not precisely match predicted contours of constant dust flux from Phoebe, ii) there are dark-floored craters in Iapetus' high-albedo hemisphere, and iii) Iapetus' North pole is brighter than parts of the trailing hemisphere. These problems are greatly reduced with the realization that Iapetus took nearly a billion years to become tidally locked to Saturn. I suggest the following scenario for the origin of the black/while dichotomy on Iapetus. Phoebe was probably captured early in the Solar System's history, well before Iapetus' spin slowed to its present synchronous rate. While Iapetus was spinning rapidly, dust from Phoebe accumulated at all longitudes on Iapetus uniformly. The accumulation was greatest near Iapetus' equator and decreased with roughly a cosine dependence toward the poles where the dust flux was lowest. After Iapetus became tidally locked, its trailing side was shielded from Phoebe dust, and volatile ice accumulated there burying the dark Phoebe material. Large impacts on the trailing side have dredged up some ancient Phoebe debris, creating the dark-floored craters. In addition, impacts have mixed dark debris with icy material, thereby lowering the albedo of the trailing side. Iapetus' poles are the brightest parts of the satellite simply because little Phoebe dust ever

  7. Galaxy evolution. Evidence for mature bulges and an inside-out quenching phase 3 billion years after the Big Bang.

    PubMed

    Tacchella, S; Carollo, C M; Renzini, A; Förster Schreiber, N M; Lang, P; Wuyts, S; Cresci, G; Dekel, A; Genzel, R; Lilly, S J; Mancini, C; Newman, S; Onodera, M; Shapley, A; Tacconi, L; Woo, J; Zamorani, G

    2015-04-17

    Most present-day galaxies with stellar masses ≥10(11) solar masses show no ongoing star formation and are dense spheroids. Ten billion years ago, similarly massive galaxies were typically forming stars at rates of hundreds solar masses per year. It is debated how star formation ceased, on which time scales, and how this "quenching" relates to the emergence of dense spheroids. We measured stellar mass and star-formation rate surface density distributions in star-forming galaxies at redshift 2.2 with ~1-kiloparsec resolution. We find that, in the most massive galaxies, star formation is quenched from the inside out, on time scales less than 1 billion years in the inner regions, up to a few billion years in the outer disks. These galaxies sustain high star-formation activity at large radii, while hosting fully grown and already quenched bulges in their cores.

  8. Switching To Less-Expensive Blindness Drug Could Save Medicare Part B $18 Billion Over A Ten-Year Period

    PubMed Central

    Hutton, DW; Newman-Casey, PA; Tavag, M; Zacks, DN; Stein, JD

    2014-01-01

    The biologic drugs bevacizumab and ranibizumab have revolutionized treatment of diabetic macular edema and macular degeneration, leading causes of blindness. Ophthalmologic use of these drugs has increased, now accounting for roughly one-sixth of the Medicare Part B drug budget. Ranibizumab and bevacizumab have similar efficacy and potentially minor differences in adverse event rates, but at $2,023 per dose, ranibizumab costs forty times more than bevacizumab. Using modeling methods, we predict ten-year (2010–2020) population-level costs and health benefits of using bevacizumab and ranibizumab. Our results show that if all patients were treated with the less-expensive bevacizumab instead of current usage patterns, Medicare Part B, patients, and the health care system would save $18 billion, $4.6 billion, and $29 billion, respectively. Altering patterns of use with these therapies by encouraging bevacizumab use and hastening approval of biosimilar therapies would dramatically reduce spending without substantially affecting patient outcomes. PMID:24889941

  9. Development and testing of a 180-volt dc electronic circuit breaker with a 335-ampere carry and 1200-ampere interrupt rating

    NASA Technical Reports Server (NTRS)

    Brush, A. S.; Phillips, R. L.

    1991-01-01

    NASA Lewis Research Center and associated contractors have conducted a program to assess the potential requirements for a high-current switch to conceptually design a switch using the best existing technology, and to build and demonstrate a breadboard which meets the requirements. The result is the high current remote bus isolator (HRBI). The HRBI is rated at 180 V dc, 335 A continuous with a 1200 A interrupt rating. It also incorporates remote-control and protective features called for by the Space Station Freedom PMAD dc test bed design. Two breadboard 335 A circuit breakers were built and tested that demonstrate a promising concept of paralleled current-limiting modules. The units incorporated all control and protective features required by advanced aerospace power systems. Component stresses in each unit were determined by design, and are consistent with a life of many thousands of fault operations.

  10. Formation of a planar optical waveguide by mega-electron-volt He+ and P+ ions implanted in a BiB(3)O(6) crystal.

    PubMed

    Chen, F; Hu, H; Wang, K M; Teng, B; Wang, J Y; Lu, Q M; Shen, D Y

    2001-12-15

    What is believed to be the first planar optical waveguide was formed in BiB(3)O(6) (BIBO) crystal by 2.8-MeV He(+)-ion implantation with a dose of 2x10(16)ions/cm (2) and 2.8-MeV P(+)-ion implantation with a dose of 1x10(14)ions/cm (2) at room temperature. We observed 21 darks modes for the He(+)-ion-implanted BIBO waveguides and four dark modes for the P(+)-ion-implanted waveguides. The refractive-index profile of the He(+)-implanted BIBO waveguide was analyzed. The data also suggest that the BIBO waveguides formed by MeV He(+)-ion and P(+)-ion implantation differ in their developing mechanisms.

  11. Submicron mass spectrometry imaging of single cells by combined use of mega electron volt time-of-flight secondary ion mass spectrometry and scanning transmission ion microscopy

    SciTech Connect

    Siketić, Zdravko; Bogdanović Radović, Ivančica; Jakšić, Milko; Popović Hadžija, Marijana; Hadžija, Mirko

    2015-08-31

    In order to better understand biochemical processes inside an individual cell, it is important to measure the molecular composition at the submicron level. One of the promising mass spectrometry imaging techniques that may be used to accomplish this is Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS), using MeV energy heavy ions for excitation. MeV ions have the ability to desorb large intact molecules with a yield that is several orders of magnitude higher than conventional SIMS using keV ions. In order to increase the spatial resolution of the MeV TOF-SIMS system, we propose an independent TOF trigger using a STIM (scanning transmission ion microscopy) detector that is placed just behind the thin transmission target. This arrangement is suitable for biological samples in which the STIM detector simultaneously measures the mass distribution in scanned samples. The capability of the MeV TOF-SIMS setup was demonstrated by imaging the chemical composition of CaCo-2 cells.

  12. Analogues of primeval galaxies two billion years after the Big Bang

    NASA Astrophysics Data System (ADS)

    Amorín, Ricardo; Fontana, Adriano; Pérez-Montero, Enrique; Castellano, Marco; Guaita, Lucia; Grazian, Andrea; Fèvre, Olivier Le; Ribeiro, Bruno; Schaerer, Daniel; Tasca, Lidia A. M.; Thomas, Romain; Bardelli, Sandro; Cassarà, Letizia; Cassata, Paolo; Cimatti, Andrea; Contini, Thierry; Barros, Stephane De; Garilli, Bianca; Giavalisco, Mauro; Hathi, Nimish; Koekemoer, Anton; Le Brun, Vincent; Lemaux, Brian C.; Maccagni, Dario; Pentericci, Laura; Pforr, Janine; Talia, Margherita; Tresse, Laurence; Vanzella, Eros; Vergani, Daniela; Zamorani, Giovanni; Zucca, Elena; Merlin, Emiliano

    2017-03-01

    Deep observations are revealing a growing number of young galaxies in the first billion years of cosmic time1. Compared to typical galaxies at later times, they show more extreme emission-line properties2, higher star formation rates3, lower masses4, and smaller sizes5. However, their faintness precludes studies of their chemical abundances and ionization conditions, strongly limiting our understanding of the physics driving early galaxy build-up and metal enrichment. Here we study a rare population of ultraviolet-selected, low-luminosity galaxies at redshift 2.4 < z < 3.5 that exhibit all the rest-frame properties expected from primeval galaxies. These low-mass, highly compact systems are rapidly forming galaxies able to double their stellar mass in only a few tens of millions of years. They are characterized by very blue ultraviolet spectra with weak absorption features and bright nebular emission lines, which imply hard radiation fields from young hot massive stars6,7. Their highly ionized gas phase has strongly sub-solar carbon and oxygen abundances, with metallicities more than a factor of two lower than that found in typical galaxies of similar mass and star formation rate at z≤2.58. These young galaxies reveal an early and short stage in the assembly of their galactic structures and their chemical evolution, a vigorous phase that is likely to be dominated by the effects of gas-rich mergers, accretion of metal-poor gas and strong outflows.

  13. Rapid analysis of perchlorate in drinking water at parts per billion levels using microchip electrophoresis.

    PubMed

    Gertsch, Jana C; Noblitt, Scott D; Cropek, Donald M; Henry, Charles S

    2010-05-01

    A microchip capillary electrophoresis (MCE) system has been developed for the determination of perchlorate in drinking water. The United States Environmental Protection Agency (USEPA) recently proposed a health advisory limit for perchlorate in drinking water of 15 parts per billion (ppb), a level requiring large, sophisticated instrumentation, such as ion chromatography coupled with mass spectrometry (IC-MS), for detection. An inexpensive, portable system is desired for routine online monitoring applications of perchlorate in drinking water. Here, we present an MCE method using contact conductivity detection for perchlorate determination. The method has several advantages, including reduced analysis times relative to IC, inherent portability, high selectivity, and minimal sample pretreatment. Resolution of perchlorate from more abundant ions was achieved using zwitterionic, sulfobetaine surfactants, N-hexadecyl-N,N-dimethyl-3-ammonio-1-propane sulfonate (HDAPS) and N-tetradecyl-N,N-dimethyl-3-ammonio-1-propane sulfonate (TDAPS). The system performance and the optimization of the separation chemistry, including the use of these surfactants to resolve perchlorate from other anions, are discussed in this work. The system is capable of detection limits of 3.4 +/- 1.8 ppb (n = 6) in standards and 5.6 +/- 1.7 ppb (n = 6) in drinking water.

  14. A Massive Galaxy in Its Core Formation Phase Three Billion Years After the Big Bang

    NASA Technical Reports Server (NTRS)

    Nelson, Erica; van Dokkum, Pieter; Franx, Marijn; Brammer, Gabriel; Momcheva, Ivelina; Schreiber, Natascha M. Forster; da Cunha, Elisabete; Tacconi, Linda; Bezanson, Rachel; Kirkpatrick, Allison; Leja, Joel; Rix, Hans-Walter; Skelton, Rosalind; van der Wel, Arjen; Whitaker, Katherine; Wuyts, Stijn

    2014-01-01

    Most massive galaxies are thought to have formed their dense stellar cores at early cosmic epochs. However, cores in their formation phase have not yet been observed. Previous studies have found galaxies with high gas velocity dispersions or small apparent sizes but so far no objects have been identified with both the stellar structure and the gas dynamics of a forming core. Here we present a candidate core in formation 11 billion years ago, at z = 2.3. GOODS-N-774 has a stellar mass of 1.0 × 10 (exp 11) solar mass, a half-light radius of 1.0 kpc, and a star formation rate of 90 (sup +45 / sub -20) solar mass/yr. The star forming gas has a velocity dispersion 317 plus or minus 30 km/s, amongst the highest ever measured. It is similar to the stellar velocity dispersions of the putative descendants of GOODS-N-774, compact quiescent galaxies at z is approximately equal to 2 (exp 8-11) and giant elliptical galaxies in the nearby Universe. Galaxies such as GOODS-N-774 appear to be rare; however, from the star formation rate and size of the galaxy we infer that many star forming cores may be heavily obscured, and could be missed in optical and near-infrared surveys.

  15. A role for copper in protozoan grazing - two billion years selecting for bacterial copper resistance.

    PubMed

    Hao, Xiuli; Lüthje, Freja; Rønn, Regin; German, Nadezhda A; Li, Xuanji; Huang, Fuyi; Kisaka, Javan; Huffman, David; Alwathnani, Hend A; Zhu, Yong-Guan; Rensing, Christopher

    2016-11-01

    The Great Oxidation Event resulted in integration of soft metals in a wide range of biochemical processes including, in our opinion, killing of bacteria by protozoa. Compared to pressure from anthropologic copper contamination, little is known on impacts of protozoan predation on maintenance of copper resistance determinants in bacteria. To evaluate the role of copper and other soft metals in predatory mechanisms of protozoa, we examined survival of bacteria mutated in different transition metal efflux or uptake systems in the social amoeba Dictyostelium discoideum. Our data demonstrated a strong correlation between the presence of copper/zinc efflux as well as iron/manganese uptake, and bacterial survival in amoebae. The growth of protozoa, in turn, was dependent on bacterial copper sensitivity. The phagocytosis of bacteria induced upregulation of Dictyostelium genes encoding the copper uptake transporter p80 and a triad of Cu(I)-translocating PIB -type ATPases. Accumulated Cu(I) in Dictyostelium was monitored using a copper biosensor bacterial strain. Altogether, our data demonstrate that Cu(I) is ultimately involved in protozoan predation of bacteria, supporting our hypothesis that protozoan grazing selected for the presence of copper resistance determinants for about two billion years.

  16. Potentially biogenic carbon preserved in a 4.1 billion-year-old zircon.

    PubMed

    Bell, Elizabeth A; Boehnke, Patrick; Harrison, T Mark; Mao, Wendy L

    2015-11-24

    Evidence of life on Earth is manifestly preserved in the rock record. However, the microfossil record only extends to ∼ 3.5 billion years (Ga), the chemofossil record arguably to ∼ 3.8 Ga, and the rock record to 4.0 Ga. Detrital zircons from Jack Hills, Western Australia range in age up to nearly 4.4 Ga. From a population of over 10,000 Jack Hills zircons, we identified one >3.8-Ga zircon that contains primary graphite inclusions. Here, we report carbon isotopic measurements on these inclusions in a concordant, 4.10 ± 0.01-Ga zircon. We interpret these inclusions as primary due to their enclosure in a crack-free host as shown by transmission X-ray microscopy and their crystal habit. Their δ(13)CPDB of -24 ± 5‰ is consistent with a biogenic origin and may be evidence that a terrestrial biosphere had emerged by 4.1 Ga, or ∼ 300 My earlier than has been previously proposed.

  17. The controversial "Cambrian" fossils of the Vindhyan are real but more than a billion years older.

    PubMed

    Bengtson, Stefan; Belivanova, Veneta; Rasmussen, Birger; Whitehouse, Martin

    2009-05-12

    The age of the Vindhyan sedimentary basin in central India is controversial, because geochronology indicating early Proterozoic ages clashes with reports of Cambrian fossils. We present here an integrated paleontologic-geochronologic investigation to resolve this conundrum. New sampling of Lower Vindhyan phosphoritic stromatolitic dolomites from the northern flank of the Vindhyans confirms the presence of fossils most closely resembling those found elsewhere in Cambrian deposits: annulated tubes, embryo-like globules with polygonal surface pattern, and filamentous and coccoidal microbial fabrics similar to Girvanella and Renalcis. None of the fossils, however, can be ascribed to uniquely Cambrian or Ediacaran taxa. Indeed, the embryo-like globules are not interpreted as fossils at all but as former gas bubbles trapped in mucus-rich cyanobacterial mats. Direct dating of the same fossiliferous phosphorite yielded a Pb-Pb isochron of 1,650 +/- 89 (2sigma) million years ago, confirming the Paleoproterozoic age of the fossils. New U-Pb geochronology of zircons from tuffaceous mudrocks in the Lower Vindhyan Porcellanite Formation on the southern flank of the Vindhyans give comparable ages. The Vindhyan phosphorites provide a window of 3-dimensionally preserved Paleoproterozoic fossils resembling filamentous and coccoidal cyanobacteria and filamentous eukaryotic algae, as well as problematic forms. Like Neoproterozoic phosphorites a billion years later, the Vindhyan deposits offer important new insights into the nature and diversity of life, and in particular, the early evolution of multicellular eukaryotes.

  18. Rapid oxygenation of Earth's atmosphere 2.33 billion years ago.

    PubMed

    Luo, Genming; Ono, Shuhei; Beukes, Nicolas J; Wang, David T; Xie, Shucheng; Summons, Roger E

    2016-05-01

    Molecular oxygen (O2) is, and has been, a primary driver of biological evolution and shapes the contemporary landscape of Earth's biogeochemical cycles. Although "whiffs" of oxygen have been documented in the Archean atmosphere, substantial O2 did not accumulate irreversibly until the Early Paleoproterozoic, during what has been termed the Great Oxygenation Event (GOE). The timing of the GOE and the rate at which this oxygenation took place have been poorly constrained until now. We report the transition (that is, from being mass-independent to becoming mass-dependent) in multiple sulfur isotope signals of diagenetic pyrite in a continuous sedimentary sequence in three coeval drill cores in the Transvaal Supergroup, South Africa. These data precisely constrain the GOE to 2.33 billion years ago. The new data suggest that the oxygenation occurred rapidly-within 1 to 10 million years-and was followed by a slower rise in the ocean sulfate inventory. Our data indicate that a climate perturbation predated the GOE, whereas the relationships among GOE, "Snowball Earth" glaciation, and biogeochemical cycling will require further stratigraphic correlation supported with precise chronologies and paleolatitude reconstructions.

  19. Large data analysis: automatic visual personal identification in a demography of 1.2 billion persons

    NASA Astrophysics Data System (ADS)

    Daugman, John

    2014-05-01

    The largest biometric deployment in history is now underway in India, where the Government is enrolling the iris patterns (among other data) of all 1.2 billion citizens. The purpose of the Unique Identification Authority of India (UIDAI) is to ensure fair access to welfare benefits and entitlements, to reduce fraud, and enhance social inclusion. Only a minority of Indian citizens have bank accounts; only 4 percent possess passports; and less than half of all aid money reaches its intended recipients. A person who lacks any means of establishing their identity is excluded from entitlements and does not officially exist; thus the slogan of UIDAI is: To give the poor an identity." This ambitious program enrolls a million people every day, across 36,000 stations run by 83 agencies, with a 3-year completion target for the entire national population. The halfway point was recently passed with more than 600 million persons now enrolled. In order to detect and prevent duplicate identities, every iris pattern that is enrolled is first compared against all others enrolled so far; thus the daily workflow now requires 600 trillion (or 600 million-million) iris cross-comparisons. Avoiding identity collisions (False Matches) requires high biometric entropy, and achieving the tremendous match speed requires phase bit coding. Both of these requirements are being delivered operationally by wavelet methods developed by the author for encoding and comparing iris patterns, which will be the focus of this Large Data Award" presentation.

  20. Prodigious degassing of a billion years of accumulated radiogenic helium at Yellowstone

    NASA Astrophysics Data System (ADS)

    Lowenstern, J. B.; Evans, W. C.; Bergfeld, D.; Hunt, A. G.

    2014-02-01

    Helium is used as a critical tracer throughout the Earth sciences, where its relatively simple isotopic systematics is used to trace degassing from the mantle, to date groundwater and to time the rise of continents. The hydrothermal system at Yellowstone National Park is famous for its high helium-3/helium-4 isotope ratio, commonly cited as evidence for a deep mantle source for the Yellowstone hotspot. However, much of the helium emitted from this region is actually radiogenic helium-4 produced within the crust by α-decay of uranium and thorium. Here we show, by combining gas emission rates with chemistry and isotopic analyses, that crustal helium-4 emission rates from Yellowstone exceed (by orders of magnitude) any conceivable rate of generation within the crust. It seems that helium has accumulated for (at least) many hundreds of millions of years in Archaean (more than 2.5 billion years old) cratonic rocks beneath Yellowstone, only to be liberated over the past two million years by intense crustal metamorphism induced by the Yellowstone hotspot. Our results demonstrate the extremes in variability of crustal helium efflux on geologic timescales and imply crustal-scale open-system behaviour of helium in tectonically and magmatically active regions.

  1. Prodigious degassing of a billion years of accumulated radiogenic helium at Yellowstone.

    PubMed

    Lowenstern, J B; Evans, W C; Bergfeld, D; Hunt, A G

    2014-02-20

    Helium is used as a critical tracer throughout the Earth sciences, where its relatively simple isotopic systematics is used to trace degassing from the mantle, to date groundwater and to time the rise of continents. The hydrothermal system at Yellowstone National Park is famous for its high helium-3/helium-4 isotope ratio, commonly cited as evidence for a deep mantle source for the Yellowstone hotspot. However, much of the helium emitted from this region is actually radiogenic helium-4 produced within the crust by α-decay of uranium and thorium. Here we show, by combining gas emission rates with chemistry and isotopic analyses, that crustal helium-4 emission rates from Yellowstone exceed (by orders of magnitude) any conceivable rate of generation within the crust. It seems that helium has accumulated for (at least) many hundreds of millions of years in Archaean (more than 2.5 billion years old) cratonic rocks beneath Yellowstone, only to be liberated over the past two million years by intense crustal metamorphism induced by the Yellowstone hotspot. Our results demonstrate the extremes in variability of crustal helium efflux on geologic timescales and imply crustal-scale open-system behaviour of helium in tectonically and magmatically active regions.

  2. Prodigious degassing of a billion years of accumulated radiogenic helium at Yellowstone

    USGS Publications Warehouse

    Lowenstern, Jacob B.; Evans, William C.; Bergfeld, D.; Hunt, Andrew G.

    2014-01-01

    Helium is used as a critical tracer throughout the Earth sciences, where its relatively simple isotopic systematics is used to trace degassing from the mantle, to date groundwater and to time the rise of continents1. The hydrothermal system at Yellowstone National Park is famous for its high helium-3/helium-4 isotope ratio, commonly cited as evidence for a deep mantle source for the Yellowstone hotspot2. However, much of the helium emitted from this region is actually radiogenic helium-4 produced within the crust by α-decay of uranium and thorium. Here we show, by combining gas emission rates with chemistry and isotopic analyses, that crustal helium-4 emission rates from Yellowstone exceed (by orders of magnitude) any conceivable rate of generation within the crust. It seems that helium has accumulated for (at least) many hundreds of millions of years in Archaean (more than 2.5 billion years old) cratonic rocks beneath Yellowstone, only to be liberated over the past two million years by intense crustal metamorphism induced by the Yellowstone hotspot. Our results demonstrate the extremes in variability of crustal helium efflux on geologic timescales and imply crustal-scale open-system behaviour of helium in tectonically and magmatically active regions.

  3. Sharing global CO2 emission reductions among one billion high emitters.

    PubMed

    Chakravarty, Shoibal; Chikkatur, Ananth; de Coninck, Heleen; Pacala, Stephen; Socolow, Robert; Tavoni, Massimo

    2009-07-21

    We present a framework for allocating a global carbon reduction target among nations, in which the concept of "common but differentiated responsibilities" refers to the emissions of individuals instead of nations. We use the income distribution of a country to estimate how its fossil fuel CO(2) emissions are distributed among its citizens, from which we build up a global CO(2) distribution. We then propose a simple rule to derive a universal cap on global individual emissions and find corresponding limits on national aggregate emissions from this cap. All of the world's high CO(2)-emitting individuals are treated the same, regardless of where they live. Any future global emission goal (target and time frame) can be converted into national reduction targets, which are determined by "Business as Usual" projections of national carbon emissions and in-country income distributions. For example, reducing projected global emissions in 2030 by 13 GtCO(2) would require the engagement of 1.13 billion high emitters, roughly equally distributed in 4 regions: the U.S., the OECD minus the U.S., China, and the non-OECD minus China. We also modify our methodology to place a floor on emissions of the world's lowest CO(2) emitters and demonstrate that climate mitigation and alleviation of extreme poverty are largely decoupled.

  4. Genetic Code Mutations: The Breaking of a Three Billion Year Invariance

    PubMed Central

    Mat, Wai-Kin; Xue, Hong; Wong, J. Tze-Fei

    2010-01-01

    The genetic code has been unchanging for some three billion years in its canonical ensemble of encoded amino acids, as indicated by the universal adoption of this ensemble by all known organisms. Code mutations beginning with the encoding of 4-fluoro-Trp by Bacillus subtilis, initially replacing and eventually displacing Trp from the ensemble, first revealed the intrinsic mutability of the code. This has since been confirmed by a spectrum of other experimental code alterations in both prokaryotes and eukaryotes. To shed light on the experimental conversion of a rigidly invariant code to a mutating code, the present study examined code mutations determining the propagation of Bacillus subtilis on Trp and 4-, 5- and 6-fluoro-tryptophans. The results obtained with the mutants with respect to cross-inhibitions between the different indole amino acids, and the growth effects of individual nutrient withdrawals rendering essential their biosynthetic pathways, suggested that oligogenic barriers comprising sensitive proteins which malfunction with amino acid analogues provide effective mechanisms for preserving the invariance of the code through immemorial time, and mutations of these barriers open up the code to continuous change. PMID:20808824

  5. Potentially biogenic carbon preserved in a 4.1 billion-year-old zircon

    DOE PAGES

    Bell, Elizabeth A.; Boehnke, Patrick; Harrison, T. Mark; ...

    2015-10-19

    Here, evidence of life on Earth is manifestly preserved in the rock record. However, the microfossil record only extends to ~3.5 billion years (Ga), the chemofossil record arguably to ~3.8 Ga, and the rock record to 4.0 Ga. Detrital zircons from Jack Hills, Western Australia range in age up to nearly 4.4 Ga. From a population of over 10,000 Jack Hills zircons, we identified one >3.8-Ga zircon that contains primary graphite inclusions. Here, we report carbon isotopic measurements on these inclusions in a concordant, 4.10 ± 0.01-Ga zircon. We interpret these inclusions as primary due to their enclosure in amore » crack-free host as shown by transmission X-ray microscopy and their crystal habit. Their δ13CPDB of –24 ± 5‰ is consistent with a biogenic origin and may be evidence that a terrestrial biosphere had emerged by 4.1 Ga, or ~300 My earlier than has been previously proposed.« less

  6. Potentially biogenic carbon preserved in a 4.1 billion-year-old zircon

    SciTech Connect

    Bell, Elizabeth A.; Boehnke, Patrick; Harrison, T. Mark; Mao, Wendy L.

    2015-10-19

    Here, evidence of life on Earth is manifestly preserved in the rock record. However, the microfossil record only extends to ~3.5 billion years (Ga), the chemofossil record arguably to ~3.8 Ga, and the rock record to 4.0 Ga. Detrital zircons from Jack Hills, Western Australia range in age up to nearly 4.4 Ga. From a population of over 10,000 Jack Hills zircons, we identified one >3.8-Ga zircon that contains primary graphite inclusions. Here, we report carbon isotopic measurements on these inclusions in a concordant, 4.10 ± 0.01-Ga zircon. We interpret these inclusions as primary due to their enclosure in a crack-free host as shown by transmission X-ray microscopy and their crystal habit. Their δ13CPDB of –24 ± 5‰ is consistent with a biogenic origin and may be evidence that a terrestrial biosphere had emerged by 4.1 Ga, or ~300 My earlier than has been previously proposed.

  7. Enhanced cellular preservation by clay minerals in 1 billion-year-old lakes.

    PubMed

    Wacey, David; Saunders, Martin; Roberts, Malcolm; Menon, Sarath; Green, Leonard; Kong, Charlie; Culwick, Timothy; Strother, Paul; Brasier, Martin D

    2014-07-28

    Organic-walled microfossils provide the best insights into the composition and evolution of the biosphere through the first 80 percent of Earth history. The mechanism of microfossil preservation affects the quality of biological information retained and informs understanding of early Earth palaeo-environments. We here show that 1 billion-year-old microfossils from the non-marine Torridon Group are remarkably preserved by a combination of clay minerals and phosphate, with clay minerals providing the highest fidelity of preservation. Fe-rich clay mostly occurs in narrow zones in contact with cellular material and is interpreted as an early microbially-mediated phase enclosing and replacing the most labile biological material. K-rich clay occurs within and exterior to cell envelopes, forming where the supply of Fe had been exhausted. Clay minerals inter-finger with calcium phosphate that co-precipitated with the clays in the sub-oxic zone of the lake sediments. This type of preservation was favoured in sulfate-poor environments where Fe-silicate precipitation could outcompete Fe-sulfide formation. This work shows that clay minerals can provide an exceptionally high fidelity of microfossil preservation and extends the known geological range of this fossilization style by almost 500 Ma. It also suggests that the best-preserved microfossils of this time may be found in low-sulfate environments.

  8. If slow rate of health care spending growth persists, projections may be off by $770 billion.

    PubMed

    Cutler, David M; Sahni, Nikhil R

    2013-05-01

    Despite earlier forecasts to the contrary, US health care spending growth has slowed in the past four years, continuing a trend that began in the early 2000s. In this article we attempt to identify why US health care spending growth has slowed, and we explore the spending implications if the trend continues for the next decade. We find that the 2007-09 recession, a one-time event, accounted for 37 percent of the slowdown between 2003 and 2012. A decline in private insurance coverage and cuts to some Medicare payment rates accounted for another 8 percent of the slowdown, leaving 55 percent of the spending slowdown unexplained. We conclude that a host of fundamental changes--including less rapid development of imaging technology and new pharmaceuticals, increased patient cost sharing, and greater provider efficiency--were responsible for the majority of the slowdown in spending growth. If these trends continue during 2013-22, public-sector health care spending will be as much as $770 billion less than predicted. Such lower levels of spending would have an enormous impact on the US economy and on government and household finances.

  9. Rapid oxygenation of Earth’s atmosphere 2.33 billion years ago

    PubMed Central

    Luo, Genming; Ono, Shuhei; Beukes, Nicolas J.; Wang, David T.; Xie, Shucheng; Summons, Roger E.

    2016-01-01

    Molecular oxygen (O2) is, and has been, a primary driver of biological evolution and shapes the contemporary landscape of Earth’s biogeochemical cycles. Although “whiffs” of oxygen have been documented in the Archean atmosphere, substantial O2 did not accumulate irreversibly until the Early Paleoproterozoic, during what has been termed the Great Oxygenation Event (GOE). The timing of the GOE and the rate at which this oxygenation took place have been poorly constrained until now. We report the transition (that is, from being mass-independent to becoming mass-dependent) in multiple sulfur isotope signals of diagenetic pyrite in a continuous sedimentary sequence in three coeval drill cores in the Transvaal Supergroup, South Africa. These data precisely constrain the GOE to 2.33 billion years ago. The new data suggest that the oxygenation occurred rapidly—within 1 to 10 million years—and was followed by a slower rise in the ocean sulfate inventory. Our data indicate that a climate perturbation predated the GOE, whereas the relationships among GOE, “Snowball Earth” glaciation, and biogeochemical cycling will require further stratigraphic correlation supported with precise chronologies and paleolatitude reconstructions. PMID:27386544

  10. GERLUMPH Data Release 2: 2.5 Billion Simulated Microlensing Light Curves

    NASA Astrophysics Data System (ADS)

    Vernardos, G.; Fluke, C. J.; Bate, N. F.; Croton, D.; Vohl, D.

    2015-04-01

    In the upcoming synoptic all-sky survey era of astronomy, thousands of new multiply imaged quasars are expected to be discovered and monitored regularly. Light curves from the images of gravitationally lensed quasars are further affected by superimposed variability due to microlensing. In order to disentangle the microlensing from the intrinsic variability of the light curves, the time delays between the multiple images have to be accurately measured. The resulting microlensing light curves can then be analyzed to reveal information about the background source, such as the size of the quasar accretion disk. In this paper we present the most extensive and coherent collection of simulated microlensing light curves; we have generated \\gt 2.5 billion light curves using the GERLUMPH high resolution microlensing magnification maps. Our simulations can be used to train algorithms to measure lensed quasar time delays, plan future monitoring campaigns, and study light curve properties throughout parameter space. Our data are openly available to the community and are complemented by online eResearch tools, located at http://gerlumph.swin.edu.au.

  11. Potentially biogenic carbon preserved in a 4.1 billion-year-old zircon

    PubMed Central

    Bell, Elizabeth A.; Harrison, T. Mark; Mao, Wendy L.

    2015-01-01

    Evidence of life on Earth is manifestly preserved in the rock record. However, the microfossil record only extends to ∼3.5 billion years (Ga), the chemofossil record arguably to ∼3.8 Ga, and the rock record to 4.0 Ga. Detrital zircons from Jack Hills, Western Australia range in age up to nearly 4.4 Ga. From a population of over 10,000 Jack Hills zircons, we identified one >3.8-Ga zircon that contains primary graphite inclusions. Here, we report carbon isotopic measurements on these inclusions in a concordant, 4.10 ± 0.01-Ga zircon. We interpret these inclusions as primary due to their enclosure in a crack-free host as shown by transmission X-ray microscopy and their crystal habit. Their δ13CPDB of −24 ± 5‰ is consistent with a biogenic origin and may be evidence that a terrestrial biosphere had emerged by 4.1 Ga, or ∼300 My earlier than has been previously proposed. PMID:26483481

  12. Providing safe drinking water to 1.2 billion unserved people

    SciTech Connect

    Gadgil, Ashok J.; Derby, Elisabeth A.

    2003-06-01

    Despite substantial advances in the past 100 years in public health, technology and medicine, 20% of the world population, mostly comprised of the poor population segments in developing countries (DCs), still does not have access to safe drinking water. To reach the United Nations (UN) Millennium Goal of halving the number of people without access to safe water by 2015, the global community will need to provide an additional one billion urban residents and 600 million rural residents with safe water within the next twelve years. This paper examines current water treatment measures and implementation methods for delivery of safe drinking water, and offers suggestions for making progress towards the goal of providing a timely and equitable solution for safe water provision. For water treatment, based on the serious limitations of boiling water and chlorination, we suggest an approach based on filtration coupled with ultraviolet (UV) disinfection, combined with public education. Additionally, owing to the capacity limitations for non-governmental organizations (NGOs) to take on this task primarily on their own, we suggest a strategy based on financially sustainable models that include the private sector as well as NGOs.

  13. Enhanced cellular preservation by clay minerals in 1 billion-year-old lakes

    PubMed Central

    Wacey, David; Saunders, Martin; Roberts, Malcolm; Menon, Sarath; Green, Leonard; Kong, Charlie; Culwick, Timothy; Strother, Paul; Brasier, Martin D.

    2014-01-01

    Organic-walled microfossils provide the best insights into the composition and evolution of the biosphere through the first 80 percent of Earth history. The mechanism of microfossil preservation affects the quality of biological information retained and informs understanding of early Earth palaeo-environments. We here show that 1 billion-year-old microfossils from the non-marine Torridon Group are remarkably preserved by a combination of clay minerals and phosphate, with clay minerals providing the highest fidelity of preservation. Fe-rich clay mostly occurs in narrow zones in contact with cellular material and is interpreted as an early microbially-mediated phase enclosing and replacing the most labile biological material. K-rich clay occurs within and exterior to cell envelopes, forming where the supply of Fe had been exhausted. Clay minerals inter-finger with calcium phosphate that co-precipitated with the clays in the sub-oxic zone of the lake sediments. This type of preservation was favoured in sulfate-poor environments where Fe-silicate precipitation could outcompete Fe-sulfide formation. This work shows that clay minerals can provide an exceptionally high fidelity of microfossil preservation and extends the known geological range of this fossilization style by almost 500 Ma. It also suggests that the best-preserved microfossils of this time may be found in low-sulfate environments. PMID:25068404

  14. Constraints on the first billion years of the geodynamo from paleointensity studies of zircons

    NASA Astrophysics Data System (ADS)

    Tarduno, John; Cottrell, Rory; Davis, William

    2014-05-01

    Several lines of reasoning, including new ideas on core thermal conductivity, suggest that onset of a strong geomagnetic field might have been delayed by one billion years (or more) after the lunar forming event. Here we extend the Proterozoic/Archean to Paleoarchean record of the geomagnetic field constrained by single crystal paleointensity (SCP) analyses (Tarduno et al., Science, 2010) to older times using zircons containing minute magnetic inclusions. Specifically, we focus on samples from the Jack Hills (Yilgarn Craton, Western Australia). We employ a CO2 laser demagnetization system and a small bore (6.3 mm) 3-component DC SQUID magnetometer; the latter offers the highest currently available moment resolution. Sample age is analyzed using SHRIMP U-Pb geochronology. Preliminary data support the presence of a relatively strong Paleoarchean field produced by a core dynamo, extending the known record by at least 100 million years, to approximately 3.55 Ga. These data only serve to exacerbate the apparent problem posed by the presence of a Paleoarchean dynamo. Alternative dynamo driving mechanisms, or efficient core/lowermost mantle heat loss processes unique to the Paleoarchean (and older times) might have been at work. We will discuss these processes, and our efforts to study even older Eoarchean-Hadean zircons.

  15. Energetic electrons in the magnetosphere of jupiter.

    PubMed

    Van Allen, J A; Baker, D N; Randall, B A; Thomsen, M F; Sentman, D D; Flindt, H R

    1974-01-25

    Observations of energetic electrons ( greater, similar 0.07 million electron volts) show that the outer magnetosphere of Jupiter consists of a thin disklike, quasitrapping region extending from about 20 to 100 planetary radii (R(J)). This magnetodisk is confined to the vicinity of the magnetic equatorial plane and appears to be an approximate figure of revolution about the magnetic axis of the planet. Hard trapping is observed within a radial distance of about 20 R(J). The omnidirectional intensity J(0) of electrons with energy greater, similar 21 million electron volts within the region 3 r 20 R(J) is given by the following provisional expression in terms of radial distance r and magnetic latitude theta: J(0) = 2.1 x 10(8) exp[-(r/a) - (theta/b)(2)]. In this expression J(0) is particles per square centimeter per second; a = 1.52 R(J) for 3

  16. Suprathermal electrons produced by beam-plasma-discharge

    NASA Technical Reports Server (NTRS)

    Sharp, W. E.

    1982-01-01

    Experiments conducted with a low energy plasma lens, HARP, in the electron beam of the large vacuum chamber at Johnson Space Center indicate that an enhanced population of 50 to 300 volt electrons appear when the beam goes into the Beam-Plasma Discharge (BPD) mode. Below the BPD instability the electron distribution appears to be characterized as non-energized single particle scattering and energy loss. At 100 cm from the beam core in the BPD mode the fluxes parallel to the beam are reduced by a factor of 20 with respect to the fluxes at 25 cm. Some evidence for isotropy near the beam core is presented.

  17. Space processing of electronic materials

    NASA Technical Reports Server (NTRS)

    Holland, L. R.

    1982-01-01

    The bulk growth of solid solution alloys of mercury telluride and cadmium telluride is discussed. These alloys are usually described by the formula Hg1-xCdxTe, and are useful for the construction of infrared detectors. The electronic energy band gap can be controlled between zero and 1.6 electron volts by adjusting the composition x. The most useful materials are at x approximately 20%, suitable for detection wavelengths of about 10 micrometers. The problems of growing large crystals are rooted in the wide phase diagram of the HgTe-CdTe pseudobinary system which leads to exaggerate segregation in freezing, constitutional supercooling, and other difficulties, and in the high vapor pressure of mercury at the growth temperatures, which leads to loss of stoichiometry and to the necessity of working in strong, pressure resistant sealed containers.

  18. Archean rocks in antarctica: 2.5-billion-year uranium-lead ages of pegmatites in enderby land.

    PubMed

    Grew, E S; Manton, W I

    1979-10-26

    Uranium-lead isotopic data indicate that the granulite-facies Napier complex of Enderby Land, Antarctica, was cut by charnockitic pegmatites 2.5 billion years ago and by pegmatites lacking hypersthene 0.52 billion years ago. The 4-bil-lion-years lead-lead ages (whole rock) reported for the Napier complex are rejected since these leads developed in three stages. Reconstructions of Gondwanaland suggest that the Napier complex may be a continuation of the Archean granulitic terrain of southern India.

  19. Megascopic Eukaryotic Algae from the 2.1-Billion-Year-Old Negaunee Iron-Formation, Michigan

    NASA Astrophysics Data System (ADS)

    Han, Tsu-Ming; Runnegar, Bruce

    1992-07-01

    Hundreds of specimens of spirally coiled, megascopic, carbonaceous fossils resembling Grypania spiralis (Walcott), have been found in the 2.1-billion-year-old Negaunee Iron-Formation at the Empire Mine, near Marquette, Michigan. This occurrence of Grypania is 700 million to 1000 million years older than fossils from previously known sites in Montana, China, and India. As Grypania appears to have been a photosynthetic alga, this discovery places the origin of organelle-bearing eukaryotic cells prior to 2.1 billion years ago.

  20. Program Calculates Power Demands Of Electronic Designs

    NASA Technical Reports Server (NTRS)

    Cox, Brian

    1995-01-01

    CURRENT computer program calculates power requirements of electronic designs. For given design, CURRENT reads in applicable parts-list file and file containing current required for each part. Program also calculates power required for circuit at supply potentials of 5.5, 5.0, and 4.5 volts. Written by use of AWK utility for Sun4-series computers running SunOS 4.x and IBM PC-series and compatible computers running MS-DOS. Sun version of program (NPO-19590). PC version of program (NPO-19111).

  1. Herschel-ATLAS: rapid evolution of dust in galaxies over the last 5 billion years

    NASA Astrophysics Data System (ADS)

    Dunne, L.; Gomez, H. L.; da Cunha, E.; Charlot, S.; Dye, S.; Eales, S.; Maddox, S. J.; Rowlands, K.; Smith, D. J. B.; Auld, R.; Baes, M.; Bonfield, D. G.; Bourne, N.; Buttiglione, S.; Cava, A.; Clements, D. L.; Coppin, K. E. K.; Cooray, A.; Dariush, A.; de Zotti, G.; Driver, S.; Fritz, J.; Geach, J.; Hopwood, R.; Ibar, E.; Ivison, R. J.; Jarvis, M. J.; Kelvin, L.; Pascale, E.; Pohlen, M.; Popescu, C.; Rigby, E. E.; Robotham, A.; Rodighiero, G.; Sansom, A. E.; Serjeant, S.; Temi, P.; Thompson, M.; Tuffs, R.; van der Werf, P.; Vlahakis, C.

    2011-10-01

    We present the first direct and unbiased measurement of the evolution of the dust mass function of galaxies over the past 5 billion years of cosmic history using data from the Science Demonstration Phase of the Herschel-Astrophysical Terahertz Large Area Survey (Herschel-ATLAS). The sample consists of galaxies selected at 250 ?m which have reliable counterparts from the Sloan Digital Sky Survey (SDSS) at z < 0.5, and contains 1867 sources. Dust masses are calculated using both a single-temperature grey-body model for the spectral energy distribution and also a model with multiple temperature components. The dust temperature for either model shows no trend with redshift. Splitting the sample into bins of redshift reveals a strong evolution in the dust properties of the most massive galaxies. At z= 0.4-0.5, massive galaxies had dust masses about five times larger than in the local Universe. At the same time, the dust-to-stellar mass ratio was about three to four times larger, and the optical depth derived from fitting the UV-sub-mm data with an energy balance model was also higher. This increase in the dust content of massive galaxies at high redshift is difficult to explain using standard dust evolution models and requires a rapid gas consumption time-scale together with either a more top-heavy initial mass function (IMF), efficient mantle growth, less dust destruction or combinations of all three. This evolution in dust mass is likely to be associated with a change in overall interstellar medium mass, and points to an enhanced supply of fuel for star formation at earlier cosmic epochs.

  2. ESA's billion star surveyor - Flight operations experience from Gaia's first 1.5 Years

    NASA Astrophysics Data System (ADS)

    Milligan, D.; Rudolph, A.; Whitehead, G.; Loureiro, T.; Serpell, E.; di Marco, F.; Marie, J.; Ecale, E.

    2016-10-01

    This paper details the initial in-flight mission operations experience from ESA's ultra-precise Gaia spacecraft. Tasked with mapping the positions and movements of 1 billion stars to unprecedented precision (to the 10 s of micro-arc-second level, comparable to the width of a coin on the Moon as viewed from Earth). ESA's Science cornerstone mission is expected to also discover and chart 100,000's of new objects including near Earth Asteroids, exoplanets, brown dwarfs and Quasars. After a flawless launch 19 Dec 2013, Gaia was brought the circa 1.5 million kms into L2 via a sequence of technically demanding orbit transfer manoeuvres using onboard thrusters in thrust vectoring mode. Starting in parallel to this, and lasting 6 months, the full spacecraft was commissioned and brought gradually up to the highest operational mode. A number of problems were detected and tackled during commissioning and early routine phase operations. An apparent dimming of the on-board laser and imaged stars, was tracked down to water ice building up inside the telescope enclosure. Also apparent was more straylight than expected. Elsewhere, a micro-propulsion thruster developed unexpected performance levels and a back-up chemical thruster suffered a failed latch valve. These issues, like several others, were dealt with and solved in a series of review meetings, in-orbit special operations and newly developed procedures and on-board software changes. After commissioning Gaia was working so well that it was producing approximately 45% more science data than originally foreseen, primarily since it was able to see stars fainter than required. The mission operations concept was quickly adapted to partially automate ground operations and increase ground station time to allow the full scientific potential of Gaia to be realised.

  3. Searching for the birthplaces of open clusters with ages of several billion years

    NASA Astrophysics Data System (ADS)

    Acharova, I. A.; Shevtsova, E. S.

    2016-01-01

    We discuss the possibility of finding the birthplaces of open clusters (OC) with ages of several billion years. The proposed method is based on the comparison of the results of the chemical evolution modeling of the Galactic disk with the parameters of the cluster. Five OCs older than 7 Gyr are known: NGC6791, BH176, Collinder 261, Berkeley 17, and Berkeley 39. The oxygen and iron abundances in NGC6791 and the oxygen abundance in BH176 are twice the solar level, the heavy-element abundances in other clusters are close to the corresponding solar values. According to chemical evolution models, at the time of the formation of the objects considered the regions where the oxygen and iron abundances reached the corresponding levels extended out to 5 kpc from the Galactic center.At present time theOCs considered are located several kpc from the Galactic center. Some of these clusters are located extremely high, about 1 kpc above the disk midplane, i.e., they have been subject to some mechanism that has carried them into orbits uncharacteristic of this type of objects. It follows from a comparison with the results of chemical evolution that younger clusters with ages of 4-5 Gyr, e.g., NGC1193,M67, and others, may have formed in a broad range of Galactocentric distances. Their large heights above the disk midplane is sufficient to suggest that these clusters have moved away from their likely birthplaces. Clusters are carried far away from the Galactic disk until the present time: about 40 clusters with ages from 0 to 2 Gyr are observed at heights ranging from 300 to 750 pc.

  4. Layout finishing of a 28nm, 3 billions transistors, multi-core processor

    NASA Astrophysics Data System (ADS)

    Morey-Chaisemartin, Philippe; Beisser, Eric

    2013-06-01

    Designing a fully new 256 cores processor is a great challenge for a fabless startup. In addition to all architecture, functionalities and timing issues, the layout by itself is a bottleneck due to all the process constraints of a 28nm technology. As developers of advanced layout finishing solutions, we were involved in the design flow of this huge chip with its 3 billions transistors. We had to face the issue of dummy patterns instantiation with respect to design constraints. All the design rules to generate the "dummies" are clearly defined in the Design Rule Manual, and some automatic procedures are provided by the foundry itself, but these routines don't take care of the designer requests. Such a chip, embeds both digital parts and analog modules for clock and power management. These two different type of designs have each their own set of constraints. In both cases, the insertion of dummies should not introduce unexpected variations leading to malfunctions. For example, on digital parts were signal race conditions are critical on long wires or bus, introduction of uncontrolled parasitic along these nets are highly critical. For analog devices such as high frequency and high sensitivity comparators, the exact symmetry of the two parts of a current mirror generator should be guaranteed. Thanks to the easily customizable features of our dummies insertion tool, we were able to configure it in order to meet all the designer requirements as well as the process constraints. This paper will present all these advanced key features as well as the layout tricks used to fulfill all requirements.

  5. Large molecular gas reservoirs in ancestors of Milky Way-mass galaxies nine billion years ago

    NASA Astrophysics Data System (ADS)

    Papovich, C.; Labbé, I.; Glazebrook, K.; Quadri, R.; Bekiaris, G.; Dickinson, M.; Finkelstein, S. L.; Fisher, D.; Inami, H.; Livermore, R. C.; Spitler, L.; Straatman, C.; Tran, K.-V.

    2016-12-01

    The gas accretion and star formation histories of galaxies like the Milky Way remain an outstanding problem in astrophysics 1,2 . Observations show that 8 billion years ago, the progenitors to Milky Way-mass galaxies were forming stars 30 times faster than today and were predicted to be rich in molecular gas 3 , in contrast to the low present-day gas fractions (<10%) 4-6 . Here we show the detection of molecular gas from the CO (J = 3-2) emission (rest-frame 345.8 GHz) in galaxies at redshifts z = 1.2-1.3, selected to have the stellar mass and star formation rate of the progenitors of today's Milky Way-mass galaxies. The CO emission reveals large molecular gas masses, comparable to or exceeding the galaxy stellar masses, and implying that most of the baryons are in cold gas, not stars. The total luminosities of the galaxies from star formation and CO luminosities yield long gas consumption timescales. Compared to local spiral galaxies, the star formation efficiency, estimated from the ratio of total infrared luminosity (L IR) to CO emission, has remained nearly constant since redshift z = 1.2, despite the order of magnitude decrease in gas fraction, consistent with the results for other galaxies at this epoch 7-10 . Therefore, the physical processes that determine the rate at which gas cools to form stars in distant galaxies appear to be similar to that in local galaxies.

  6. Survival of Pure Disk Galaxies over the Last 8 Billion Years

    NASA Astrophysics Data System (ADS)

    Sachdeva, Sonali; Saha, Kanak

    2016-03-01

    Pure disk galaxies without any bulge component, i.e., bulges that are neither classical nor pseudo, seem to have escaped the effects of merger activity that are inherent to hierarchical galaxy formation models as well as strong internal secular evolution. We discover that a significant fraction (˜15%-18%) of disk galaxies in the Hubble Deep Field (0.4\\lt z\\lt 1.0) and in the local universe (0.02\\lt z\\lt 0.05) are such pure disk systems (PDSs). The spatial distribution of light in these PDSs is well-described by a single exponential function from the outskirts to the center and appears to have remained intact over the last 8 billion years, keeping the mean central surface brightness and scale-length nearly constant. These two disk parameters of PDSs are brighter and shorter, respectively, than those of disks which are part of disk galaxies with bulges. Since the fraction of PDSs, as well as their profile-defining parameters, do not change, this indicates that these galaxies have not witnessed either major mergers or multiple minor mergers since z˜ 1. However, there is a substantial increase in their total stellar mass and total size over the same time range. This suggests that smooth accretion of cold gas via cosmic filaments is the most probable mode of their evolutions. We speculate that PDSs are dynamically hotter and cushioned in massive dark matter halos, which may prevent them from undergoing strong secular evolution.

  7. The formation of submillimetre-bright galaxies from gas infall over a billion years.

    PubMed

    Narayanan, Desika; Turk, Matthew; Feldmann, Robert; Robitaille, Thomas; Hopkins, Philip; Thompson, Robert; Hayward, Christopher; Ball, David; Faucher-Giguère, Claude-André; Kereš, Dušan

    2015-09-24

    Submillimetre-bright galaxies at high redshift are the most luminous, heavily star-forming galaxies in the Universe and are characterized by prodigious emission in the far-infrared, with a flux of at least five millijanskys at a wavelength of 850 micrometres. They reside in haloes with masses about 10(13) times that of the Sun, have low gas fractions compared to main-sequence disks at a comparable redshift, trace complex environments and are not easily observable at optical wavelengths. Their physical origin remains unclear. Simulations have been able to form galaxies with the requisite luminosities, but have otherwise been unable to simultaneously match the stellar masses, star formation rates, gas fractions and environments. Here we report a cosmological hydrodynamic galaxy formation simulation that is able to form a submillimetre galaxy that simultaneously satisfies the broad range of observed physical constraints. We find that groups of galaxies residing in massive dark matter haloes have increasing rates of star formation that peak at collective rates of about 500-1,000 solar masses per year at redshifts of two to three, by which time the interstellar medium is sufficiently enriched with metals that the region may be observed as a submillimetre-selected system. The intense star formation rates are fuelled in part by the infall of a reservoir gas supply enabled by stellar feedback at earlier times, not through major mergers. With a lifetime of nearly a billion years, our simulations show that the submillimetre-bright phase of high-redshift galaxies is prolonged and associated with significant mass buildup in early-Universe proto-clusters, and that many submillimetre-bright galaxies are composed of numerous unresolved components (for which there is some observational evidence).

  8. Atmospheric sulfur rearrangement 2.7 billion years ago: Evidence for oxygenic photosynthesis

    NASA Astrophysics Data System (ADS)

    Kurzweil, Florian; Claire, Mark; Thomazo, Christophe; Peters, Marc; Hannington, Mark; Strauss, Harald

    2013-03-01

    Mass-independently fractionated sulfur isotopes (MIF-S) provide strong evidence for an anoxic atmosphere during the Archean. Moreover, the temporal evolution of MIF-S shows increasing magnitudes between 2.7 and 2.5 Ga until the start of the Great Oxidation Event (G.O.E.) at around 2.4 Ga. The conclusion of a completely anoxic atmosphere up to the G.O.E. is in contrast to recent studies on redox-sensitive elements, which suggest slightly oxidizing conditions during continental weathering already several hundred million years prior to the G.O.E. In order to investigate this apparent inconsistency, we present multiple sulfur isotopes for 2.71 Ga pyritic black shales derived from the Kidd Creek area, Ontario, Canada. These samples display high positive Δ33S values up to 3.8‰ and the typical late Archean slope in Δ36S/Δ33S of -0.9. In contrast, the time period before (3.2-2.73 Ga) is characterized by greatly attenuated MIF-S magnitudes and a slope in Δ36S/Δ33S of -1.5. We attribute the increase in Δ33S magnitude as well as the contemporaneous change in the slope of Δ36S/Δ33S to changes in the relative reaction rate of different MIF-S source reactions and changes in atmospheric sulfur exit channels. Both of these are dependent on atmospheric CH4:CO2 and O2 mixing ratios. We propose a distinct change in atmospheric composition at 2.7 Ga resulting from increased fluxes of oxygen and methane as the best explanation for the observed Neoarchean MIF-S record. Our data and modeling results suggest that oxygenic photosynthesis was a major contributor to primary productivity 2.7 billion years ago.

  9. The transition to a sulphidic ocean approximately 1.84 billion years ago.

    PubMed

    Poulton, Simon W; Fralick, Philip W; Canfield, Donald E

    2004-09-09

    The Proterozoic aeon (2.5 to 0.54 billion years (Gyr) ago) marks the time between the largely anoxic world of the Archean (> 2.5 Gyr ago) and the dominantly oxic world of the Phanerozoic (< 0.54 Gyr ago). The course of ocean chemistry through the Proterozoic has traditionally been explained by progressive oxygenation of the deep ocean in response to an increase in atmospheric oxygen around 2.3 Gyr ago. This postulated rise in the oxygen content of the ocean is in turn thought to have led to the oxidation of dissolved iron, Fe(II), thus ending the deposition of banded iron formations (BIF) around 1.8 Gyr ago. An alternative interpretation suggests that the increasing atmospheric oxygen levels enhanced sulphide weathering on land and the flux of sulphate to the oceans. This increased rates of sulphate reduction, resulting in Fe(II) removal in the form of pyrite as the oceans became sulphidic. Here we investigate sediments from the approximately 1.8-Gyr-old Animikie group, Canada, which were deposited during the final stages of the main global period of BIF deposition. This allows us to evaluate the two competing hypotheses for the termination of BIF deposition. We use iron-sulphur-carbon (Fe-S-C) systematics to demonstrate continued ocean anoxia after the final global deposition of BIF and show that a transition to sulphidic bottom waters was ultimately responsible for the termination of BIF deposition. Sulphidic conditions may have persisted until a second major rise in oxygen between 0.8 to 0.58 Gyr ago, possibly reducing global rates of primary production and arresting the pace of algal evolution.

  10. The transition to a sulphidic ocean ~ 1.84 billion years ago

    NASA Astrophysics Data System (ADS)

    Poulton, Simon W.; Fralick, Philip W.; Canfield, Donald E.

    2004-09-01

    The Proterozoic aeon (2.5 to 0.54 billion years (Gyr) ago) marks the time between the largely anoxic world of the Archean (> 2.5Gyr ago) and the dominantly oxic world of the Phanerozoic (< 0.54Gyr ago). The course of ocean chemistry through the Proterozoic has traditionally been explained by progressive oxygenation of the deep ocean in response to an increase in atmospheric oxygen around 2.3Gyr ago. This postulated rise in the oxygen content of the ocean is in turn thought to have led to the oxidation of dissolved iron, Fe(II), thus ending the deposition of banded iron formations (BIF) around 1.8Gyr ago. An alternative interpretation suggests that the increasing atmospheric oxygen levels enhanced sulphide weathering on land and the flux of sulphate to the oceans. This increased rates of sulphate reduction, resulting in Fe(II) removal in the form of pyrite as the oceans became sulphidic. Here we investigate sediments from the ~1.8-Gyr-old Animikie group, Canada, which were deposited during the final stages of the main global period of BIF deposition. This allows us to evaluate the two competing hypotheses for the termination of BIF deposition. We use iron-sulphur-carbon (Fe-S-C) systematics to demonstrate continued ocean anoxia after the final global deposition of BIF and show that a transition to sulphidic bottom waters was ultimately responsible for the termination of BIF deposition. Sulphidic conditions may have persisted until a second major rise in oxygen between 0.8 to 0.58Gyr ago, possibly reducing global rates of primary production and arresting the pace of algal evolution.

  11. No Photon Left Behind: How Billions of Spectral Lines are Transforming Planetary Sciences

    NASA Astrophysics Data System (ADS)

    Villanueva, Geronimo L.

    2014-06-01

    With the advent of realistic potential energy surface (PES) and dipole moment surface (DMS) descriptions, theoretically computed linelists can now synthesize accurate spectral parameters for billions of spectral lines sampling the untamed high-energy molecular domain. Being the initial driver for these databases the characterization of stellar spectra, these theoretical databases, in combination with decades of precise experimental studies (nicely compiled in community databases such as HITRAN and GEISA), are leading to unprecedented precisions in the characterization of planetary atmospheres. Cometary sciences are among the most affected by this spectroscopic revolution. Even though comets are relatively cold bodies (T˜100 K), their infrared molecular emission is mainly defined by non-LTE solar fluorescence induced by a high-energy source (Sun, T˜5600 K). In order to interpret high-resolution spectra of comets acquired with extremely powerful telescopes (e.g., Keck, VLT, NASA-IRTF), we have developed advanced non-LTE fluorescence models that integrate the high-energy dynamic range of ab-initio databases (e.g., BT2, VTT, HPT2, BYTe, TROVE) and the precision of laboratory and semi-empirical compilations (e.g., HITRAN, GEISA, CDMS, WKMC, SELP, IUPAC). These new models allow us to calculate realistic non-LTE pumps, cascades, branching-ratios, and emission rates for a broad range of excitation regimes for H2O, HDO, HCN, HNC and NH3. We have implemented elements of these compilations to the study of Mars spectra, and we are now exploring its application to modeling non-LTE emission in exoplanets. In this presentation, we present application of these advanced models to interpret highresolution spectra of comets, Mars and exoplanets.

  12. Industrial R&D Spending Reached $26.6 Billion in 1976. Science Resources Studies Highlights, May 5, 1978.

    ERIC Educational Resources Information Center

    National Science Foundation, Washington, DC. Div. of Science Resources Studies.

    This report presents data compiled as part of a comprehensive program to measure and analyze the nation's resources expended for research and development (R&D). Industry, which carries out 69% of the R&D in the United States, spent $26.6 billion on these activities in 1976, 10% above the 1975 level. In constant dollars, this presents an…

  13. Switching to less expensive blindness drug could save medicare part B $18 billion over a ten-year period.

    PubMed

    Hutton, David; Newman-Casey, Paula Anne; Tavag, Mrinalini; Zacks, David; Stein, Joshua

    2014-06-01

    The biologic drugs bevacizumab and ranibizumab have revolutionized treatment of diabetic macular edema and neovascular age-related macular degeneration, leading causes of blindness. Ophthalmologic use of these drugs has increased and now accounts for roughly one-sixth of the Medicare Part B drug budget. The two drugs have similar efficacy and potentially minor differences in adverse-event rates; however, at $2,023 per dose, ranibizumab costs forty times more than bevacizumab. Using modeling methods, we predict ten-year (2010-20) population-level costs and health benefits of using bevacizumab and ranibizumab. Our results show that if all patients were treated with the less expensive bevacizumab instead of current usage patterns, savings would amount to $18 billion for Medicare Part B and nearly $5 billion for patients. With an additional $6 billion savings in other health care expenses, the total savings would be almost $29 billion. Altering patterns of use with these therapies by encouraging bevacizumab use and hastening approval of biosimilar therapies would dramatically reduce spending without substantially affecting patient outcomes.

  14. $100 Billion: For Reform...or to Subsidize the Status Quo? Education Stimulus Watch. Special Report 1

    ERIC Educational Resources Information Center

    Smarick, Andy

    2009-01-01

    This is the first in a quarterly series of special reports on the K-12 education implications of the federal government's economic stimulus package, the American Recovery and Reinvestment Act (ARRA). That the ARRA, which was signed into law in February, will pump nearly $100 billion--an unprecedented sum of federal money--into K-12 education is…

  15. 77 FR 3075 - Resolution Plans Required for Insured Depository Institutions With $50 Billion or More in Total...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-23

    ... Plan will describe the plan to resolve each parent holding company under the Bankruptcy Code, the Rule... insurance fund or the economy, or if the parent company has been designated as a systemically important... association is over $50 billion and receives a CAMELS rating of 3 or worse or its parent receives...

  16. Low-energy electron flux and its reaction to active experimentation of Spacelab

    NASA Technical Reports Server (NTRS)

    Wilhelm, K.

    1981-01-01

    An instrument capable of observing the natural electron flux in the energy range from 0.1 to 12.0 kiloelectron volts is discussed for use in an experiment intended as a forerunner of a method that will utilize artificially accelerated electrons as tracer particles for electron fields parallel to the magnetic field. Effects that are of importance either as means of detecting the echo beam or as causes of beam perturbations (e.g., spacecraft charging effects and electron background) are to be studied. The use of electron accelerators as a tool to probe magnetospheric processes rather than to modify them is planned.

  17. Slow Electron Cooling in Colloidal Quantum Dots

    NASA Astrophysics Data System (ADS)

    Pandey, Anshu; Guyot-Sionnest, Philippe

    2008-11-01

    Hot electrons in semiconductors lose their energy very quickly (within picoseconds) to lattice vibrations. Slowing this energy loss could prove useful for more efficient photovoltaic or infrared devices. With their well-separated electronic states, quantum dots should display slow relaxation, but other mechanisms have made it difficult to observe. We report slow intraband relaxation (>1 nanosecond) in colloidal quantum dots. The small cadmium selenide (CdSe) dots, with an intraband energy separation of ~0.25 electron volts, are capped by an epitaxial zinc selenide (ZnSe) shell. The shell is terminated by a CdSe passivating layer to remove electron traps and is covered by ligands of low infrared absorbance (alkane thiols) at the intraband energy. We found that relaxation is markedly slowed with increasing ZnSe shell thickness.

  18. Limiting Superluminal Electron and Neutrino Velocities Using the 2010 Crab Nebula Flare and the IceCube PeV Neutrino Events

    NASA Technical Reports Server (NTRS)

    Stecker, Floyd W.

    2014-01-01

    The observation of two PetaelectronVolt (PeV)-scale neutrino events reported by Ice Cube allows one to place constraints on Lorentz invariance violation (LIV) in the neutrino sector. After first arguing that at least one of the PetaelectronVolt IceCube events was of extragalactic origin, I derive an upper limit for the difference between putative superluminal neutrino and electron velocities of less than or equal to approximately 5.6 x 10(exp -19) in units where c = 1, confirming that the observed PetaelectronVolt neutrinos could have reached Earth from extragalactic sources. I further derive a new constraint on the superluminal electron velocity, obtained from the observation of synchrotron radiation from the Crab Nebula flare of September, 2010. The inference that the greater than 1 GigaelectronVolt gamma-rays from synchrotron emission in the flare were produced by electrons of energy up to approx. 5.1 PetaelectronVolt indicates the nonoccurrence of vacuum Cerenkov radiation by these electrons. This implies a new, strong constraint on superluminal electron velocities delta(sub e) less than or equal to approximately 5 x 10(exp -21). It immediately follows that one then obtains an upper limit on the superluminal neutrino velocity alone of delta(sub v) less than or equal to approximately 5.6 x 10(exp -19), many orders of magnitude better than the time-of-flight constraint from the SN1987A neutrino burst. However, if the electrons are subluminal the constraint on the absolute value of delta(sub e) less than or equal to approximately 8 x 10(exp -17), obtained from the Crab Nebula gamma-ray spectrum, places a weaker constraint on superluminal neutrino velocity of delta(sub v) less than or equal to approximately 8 x 10(exp -17).

  19. Strongly baryon-dominated disk galaxies at the peak of galaxy formation ten billion years ago

    NASA Astrophysics Data System (ADS)

    Genzel, R.; Schreiber, N. M. Förster; Übler, H.; Lang, P.; Naab, T.; Bender, R.; Tacconi, L. J.; Wisnioski, E.; Wuyts, S.; Alexander, T.; Beifiori, A.; Belli, S.; Brammer, G.; Burkert, A.; Carollo, C. M.; Chan, J.; Davies, R.; Fossati, M.; Galametz, A.; Genel, S.; Gerhard, O.; Lutz, D.; Mendel, J. T.; Momcheva, I.; Nelson, E. J.; Renzini, A.; Saglia, R.; Sternberg, A.; Tacchella, S.; Tadaki, K.; Wilman, D.

    2017-03-01

    In the cold dark matter cosmology, the baryonic components of galaxies—stars and gas—are thought to be mixed with and embedded in non-baryonic and non-relativistic dark matter, which dominates the total mass of the galaxy and its dark-matter halo. In the local (low-redshift) Universe, the mass of dark matter within a galactic disk increases with disk radius, becoming appreciable and then dominant in the outer, baryonic regions of the disks of star-forming galaxies. This results in rotation velocities of the visible matter within the disk that are constant or increasing with disk radius—a hallmark of the dark-matter model. Comparisons between the dynamical mass, inferred from these velocities in rotational equilibrium, and the sum of the stellar and cold-gas mass at the peak epoch of galaxy formation ten billion years ago, inferred from ancillary data, suggest high baryon fractions in the inner, star-forming regions of the disks. Although this implied baryon fraction may be larger than in the local Universe, the systematic uncertainties (owing to the chosen stellar initial-mass function and the calibration of gas masses) render such comparisons inconclusive in terms of the mass of dark matter. Here we report rotation curves (showing rotation velocity as a function of disk radius) for the outer disks of six massive star-forming galaxies, and find that the rotation velocities are not constant, but decrease with radius. We propose that this trend arises because of a combination of two main factors: first, a large fraction of the massive high-redshift galaxy population was strongly baryon-dominated, with dark matter playing a smaller part than in the local Universe; and second, the large velocity dispersion in high-redshift disks introduces a substantial pressure term that leads to a decrease in rotation velocity with increasing radius. The effect of both factors appears to increase with redshift. Qualitatively, the observations suggest that baryons in the early

  20. The Other Inconvenient Truth: Feeding 9 Billion While Sustaining the Earth System

    NASA Astrophysics Data System (ADS)

    Foley, J. A.

    2010-12-01

    As the international community focuses on climate change as the great challenge of our era, we have been largely ignoring another looming problem — the global crisis in agriculture, food security and the environment. Our use of land, particularly for agriculture, is absolutely essential to the success of the human race: we depend on agriculture to supply us with food, feed, fiber, and, increasingly, biofuels. Without a highly efficient, productive, and resilient agricultural system, our society would collapse almost overnight. But we are demanding more and more from our global agricultural systems, pushing them to their very limits. Continued population growth (adding more than 70 million people to the world every year), changing dietary preferences (including more meat and dairy consumption), rising energy prices, and increasing needs for bioenergy sources are putting tremendous pressure on the world’s resources. And, if we want any hope of keeping up with these demands, we’ll need to double the agricultural production of the planet in the next 30 to 40 years. Meeting these huge new agricultural demands will be one of the greatest challenges of the 21st century. At present, it is completely unclear how (and if) we can do it. If this wasn’t enough, we must also address the massive environmental impacts of our current agricultural practices, which new evidence indicates rival the impacts of climate change. Simply put, providing for the basic needs of 9 billion-plus people, without ruining the biosphere in the process, will be one of the greatest challenges our species has ever faced. In this presentation, I will present a new framework for evaluating and assessing global patterns of agriculture, food / fiber / fuel production, and their relationship to the earth system, particularly in terms of changing stocks and flows of water, nutrients and carbon in our planetary environment. This framework aims to help us manage the challenges of increasing global food

  1. Strongly baryon-dominated disk galaxies at the peak of galaxy formation ten billion years ago.

    PubMed

    Genzel, R; Schreiber, N M Förster; Übler, H; Lang, P; Naab, T; Bender, R; Tacconi, L J; Wisnioski, E; Wuyts, S; Alexander, T; Beifiori, A; Belli, S; Brammer, G; Burkert, A; Carollo, C M; Chan, J; Davies, R; Fossati, M; Galametz, A; Genel, S; Gerhard, O; Lutz, D; Mendel, J T; Momcheva, I; Nelson, E J; Renzini, A; Saglia, R; Sternberg, A; Tacchella, S; Tadaki, K; Wilman, D

    2017-03-15

    In the cold dark matter cosmology, the baryonic components of galaxies-stars and gas-are thought to be mixed with and embedded in non-baryonic and non-relativistic dark matter, which dominates the total mass of the galaxy and its dark-matter halo. In the local (low-redshift) Universe, the mass of dark matter within a galactic disk increases with disk radius, becoming appreciable and then dominant in the outer, baryonic regions of the disks of star-forming galaxies. This results in rotation velocities of the visible matter within the disk that are constant or increasing with disk radius-a hallmark of the dark-matter model. Comparisons between the dynamical mass, inferred from these velocities in rotational equilibrium, and the sum of the stellar and cold-gas mass at the peak epoch of galaxy formation ten billion years ago, inferred from ancillary data, suggest high baryon fractions in the inner, star-forming regions of the disks. Although this implied baryon fraction may be larger than in the local Universe, the systematic uncertainties (owing to the chosen stellar initial-mass function and the calibration of gas masses) render such comparisons inconclusive in terms of the mass of dark matter. Here we report rotation curves (showing rotation velocity as a function of disk radius) for the outer disks of six massive star-forming galaxies, and find that the rotation velocities are not constant, but decrease with radius. We propose that this trend arises because of a combination of two main factors: first, a large fraction of the massive high-redshift galaxy population was strongly baryon-dominated, with dark matter playing a smaller part than in the local Universe; and second, the large velocity dispersion in high-redshift disks introduces a substantial pressure term that leads to a decrease in rotation velocity with increasing radius. The effect of both factors appears to increase with redshift. Qualitatively, the observations suggest that baryons in the early (high

  2. Gaia Data Release 1. Astrometry: one billion positions, two million proper motions and parallaxes

    NASA Astrophysics Data System (ADS)

    Lindegren, L.; Lammers, U.; Bastian, U.; Hernández, J.; Klioner, S.; Hobbs, D.; Bombrun, A.; Michalik, D.; Ramos-Lerate, M.; Butkevich, A.; Comoretto, G.; Joliet, E.; Holl, B.; Hutton, A.; Parsons, P.; Steidelmüller, H.; Abbas, U.; Altmann, M.; Andrei, A.; Anton, S.; Bach, N.; Barache, C.; Becciani, U.; Berthier, J.; Bianchi, L.; Biermann, M.; Bouquillon, S.; Bourda, G.; Brüsemeister, T.; Bucciarelli, B.; Busonero, D.; Carlucci, T.; Castañeda, J.; Charlot, P.; Clotet, M.; Crosta, M.; Davidson, M.; de Felice, F.; Drimmel, R.; Fabricius, C.; Fienga, A.; Figueras, F.; Fraile, E.; Gai, M.; Garralda, N.; Geyer, R.; González-Vidal, J. J.; Guerra, R.; Hambly, N. C.; Hauser, M.; Jordan, S.; Lattanzi, M. G.; Lenhardt, H.; Liao, S.; Löffler, W.; McMillan, P. J.; Mignard, F.; Mora, A.; Morbidelli, R.; Portell, J.; Riva, A.; Sarasso, M.; Serraller, I.; Siddiqui, H.; Smart, R.; Spagna, A.; Stampa, U.; Steele, I.; Taris, F.; Torra, J.; van Reeven, W.; Vecchiato, A.; Zschocke, S.; de Bruijne, J.; Gracia, G.; Raison, F.; Lister, T.; Marchant, J.; Messineo, R.; Soffel, M.; Osorio, J.; de Torres, A.; O'Mullane, W.

    2016-11-01

    Context. Gaia Data Release 1 (DR1) contains astrometric results for more than 1 billion stars brighter than magnitude 20.7 based on observations collected by the Gaia satellite during the first 14 months of its operational phase. Aims: We give a brief overview of the astrometric content of the data release and of the model assumptions, data processing, and validation of the results. Methods: For stars in common with the Hipparcos and Tycho-2 catalogues, complete astrometric single-star solutions are obtained by incorporating positional information from the earlier catalogues. For other stars only their positions are obtained, essentially by neglecting their proper motions and parallaxes. The results are validated by an analysis of the residuals, through special validation runs, and by comparison with external data. Results: For about two million of the brighter stars (down to magnitude 11.5) we obtain positions, parallaxes, and proper motions to Hipparcos-type precision or better. For these stars, systematic errors depending for example on position and colour are at a level of ± 0.3 milliarcsecond (mas). For the remaining stars we obtain positions at epoch J2015.0 accurate to 10 mas. Positions and proper motions are given in a reference frame that is aligned with the International Celestial Reference Frame (ICRF) to better than 0.1 mas at epoch J2015.0, and non-rotating with respect to ICRF to within 0.03 mas yr-1. The Hipparcos reference frame is found to rotate with respect to the Gaia DR1 frame at a rate of 0.24 mas yr-1. Conclusions: Based on less than a quarter of the nominal mission length and on very provisional and incomplete calibrations, the quality and completeness of the astrometric data in Gaia DR1 are far from what is expected for the final mission products. The present results nevertheless represent a huge improvement in the available fundamental stellar data and practical definition of the optical reference frame.

  3. Protons and Electrons in Jupiter's Magnetic Field: Results from the University of Chicago Experiment on Pioneer 10.

    PubMed

    Simpson, J A; Hamilton, D; Lentz, G; McKibben, R B; Mogro-Campero, A; Perkins, M; Pyle, K R; Tuzzolino, A J; O'gallagher, J J

    1974-01-25

    Fluxes of high energy electrons and protons are found to be highly concentrated near the magnetic equatorial plane from distances of ~ 30 to ~ 100 Jovian radii (R(J)). The 10-hour period of planetary rotation is observed as an intensity variation, which indicates that the equatorial zone of high particle fluxes is inclined with respect to the rotation axis of the planet. At radial distances [unknown] 20 R(J) the synchrotron-radiation-producing electrons with energies greater, similar 3 million electron volts rise steeply to a maximum intensity of ~ 5 x 10(8) electrons per square centimeter per second near the periapsis at 2.8 R(J). The flux of protons with energies greater, similar 30 million electron volts reaches a maximum intensity of ~ 4 x 10(6) protons per square centimeter per second at ~ 3.5 R(J) with the intensity decreasing inside this radial distance. Only for radial distances [unknown] 20 R(J) does the radiation behave in a manner which is similar to that at the earth. Burst of electrons with energies up to 30 million electron volts, each lasting about 2 days, were observed in interplanetary space beginning approximately 1 month before encounter. This radiation appears to have escaped from the Jovian bow shock or magnetosphere.

  4. SHEEBA: A spatial high energy electron beam analyzer

    NASA Astrophysics Data System (ADS)

    Galimberti, Marco; Giulietti, Antonio; Giulietti, Danilo; Gizzi, Leonida A.

    2005-05-01

    Electron bunches with large energy and angle spread are not easy to be analyzed with conventional spectrometers. In this article, a device for the detection of high energy electrons is presented. This detector, based on the traces left by electrons on a stack of dosimetric films, together with an original numerical algorithm for traces deconvolution, is able to characterize both angularly and spectrally (up to some mega-electron-volts) a broad-spectrum electron bunch. A numerical test was successfully performed with a virtual electron beam, which was in turn reconstructed using a Montecarlo code (based on the CERN library GEANT4). Due to its simplicity and small size, the spatial high energy electron beam analyzer (SHEEBA) detector is particularly suitable to be used in laser plasma acceleration experiments.

  5. Beyond the Standard Model – Searches with a Free-Electron Laser

    SciTech Connect

    A. Afanasev, O.K. Baker, K.B. Beard, G. Biallas, J. Boyce, M. Minarni, R. Ramdon, Michelle D. Shinn, P. Slocumb

    2010-02-01

    Much of the focus of Beyond the Standard Model physics searches is on the TeV scale, making use of hadron and lepton colliders. Additionally, however, there is the means to make these searches in different regions of parameter space using sub-electron volt photons from a Free Electron Laser, for example. We report on the experimental results of searches for opticalwavelength photons mixing with hypothetical hidden-sector paraphotons in the mass range between 10^-5 and 10^-2 electron volts for a mixing parameter greater than 10-7. We also report on the results of a sensitive search for scalar coupling of photons to light neutral bosons in the mass range of approximately 1.0 milli-electron volts and coupling strength greater than 10-6 GeV-1. These were generation-regeneration experiments using the “light shining through a wall” technique in which regenerated photons are searched for downstream of an optical barrier that separates it from an upstream generation region. The present results indicate no evidence for photon-paraphoton mixing or for scalar couplings of bosons to photons for the range of parameters investigated.

  6. The continuing cost of privatization: extra payments to Medicare Advantage plans jump to $11.4 billion in 2009.

    PubMed

    Biles, Brian; Pozen, Jonah; Guterman, Stuart

    2009-05-01

    The Medicare Modernization Act of 2003 explicitly increased Medicare payments to private Medicare Advantage (MA) plans. As a result, MA plans have, for the past six years, been paid more for their enrollees than they would be expected to cost in traditional fee-for-service Medicare. Payments to MA plans in 2009 are projected to be 13 percent greater than the corresponding costs in traditional Medicare--an average of $1,138 per MA plan enrollee, for a total of $11.4 billion. Although the extra payments are used to provide enrollees additional benefits, those benefits are not available to all beneficiaries-- but they are financed by general program funds. If payments to MA plans were instead equal to the spending level under traditional Medicare, the more than $150 billion in savings over 10 years could be used to finance improved benefits for the low-income elderly and disabled, or for expanding health-insurance coverage.

  7. The discovery of fullerenes in the 1.85 billion-year-old Sudbury meteorite crater

    SciTech Connect

    Becker, L.; Bada, J.L.; Winans, R.E.; Hunt, J.E.; Bunch, T.E.; French, B.M.

    1996-02-01

    Fullerenes (C{sub 60}, C{sub 70}) have been identified by laser time-of-flight and electron-ionization mass spectroscopy in rock samples (black tuff in the Onaping formation) from the crater. They were likely synthesized within the impact plume from carbon contained in the meteorite. The isotopic ratios suggest {sup 13}C enrichment. They are associated with sulfur which may have protected them. This is the largest known deposit of naturally occurring fullerenes.

  8. Naphthalenetetracarboxylic diimide layer-based transistors with nanometer oxide and side chain dielectrics operating below one volt.

    PubMed

    Jung, Byung Jun; Martinez Hardigree, Josue F; Dhar, Bal Mukund; Dawidczyk, Thomas J; Sun, Jia; See, Kevin Cua; Katz, Howard E

    2011-04-26

    We designed a new naphthalenetetracarboxylic diimide (NTCDI) semiconductor molecule with long fluoroalkylbenzyl side chains. The side chains, 1.2 nm long, not only aid in self-assembly and kinetically stabilize injected electrons but also act as part of the gate dielectric in field-effect transistors. On Si substrates coated only with the 2 nm thick native oxide, NTCDI semiconductor films were deposited with thicknesses from 17 to 120 nm. Top contact Au electrodes were deposited as sources and drains. The devices showed good transistor characteristics in air with 0.1-1 μA of drain current at 0.5 V of V(G) and V(DS) and W/L of 10-20, even though channel width (250 μm) is over 1000 times the distance (20 nm) between gate and drain electrodes. The extracted capacitance-times-mobility product, an expression of the sheet transconductance, can exceed 100 nS V(-1), 2 orders of magnitude higher than typical organic transistors. The vertical low-frequency capacitance with gate voltage applied in the accumulation regime reached as high as 650 nF/cm(2), matching the harmonic sum of capacitances of the native oxide and one side chain and indicating that some gate-induced carriers in such devices are distributed among all of the NTCDI core layers, although the preponderance of the carriers are still near the gate electrode. Besides demonstrating and analyzing thickness-dependent NTCDI-based transistor behavior, we also showed <1 V detection of dinitrotoluene vapor by such transistors.

  9. Low-energy electron intensities at large distances over the earth's polar cap

    NASA Technical Reports Server (NTRS)

    Yeager, D. M.; Frank, L. A.

    1975-01-01

    The results of the character and temporal fluctuations study of electron intensities in the energy range of hundreds of electron volts, are reported which were measured at high latitudes and altitudes on geomagnetic field lines corresponding to those of the polar cap and magnetotail lobes. It is concluded that such electron intensities are diminutive relative to those found in other regions of the magnetosphere. Severe variations of intensities were found and the magnitudes of electron intensities appear to be strongly coupled to the directions of the interplanetary magnetic fields.

  10. A billion pixels, a billion stars

    NASA Astrophysics Data System (ADS)

    Gilmore, Gerry; van Leeuwen, Floor

    2016-09-01

    The Gaia spacecraft is conducting the most ambitious and thorough census of our galaxy ever attempted, gathering data on 100,000 stars every hour. With the mission's first major data release due this month, Gerry Gilmore and Floor van Leeuwen explain how the spacecraft works and assess its likely impact on the field of astrophysics

  11. Mathematical modeling of electron transport processes in the dielectrics of MDS structures in strong fields

    SciTech Connect

    Kol'dyaev, V.I.; Svitashev, K.K.

    1987-01-01

    The authors review developments of mathematical modeling of electron processes in dielectrics in strong fields, and compare some results of the modeling obtained from the experimental data on MNOS structures. The authors study modeling of the volt-ampere characteristics; methods based on the study of the polarization kinetics of MDS structures (polarization methods); depolarization of MDS structures under isothermal conditions, and under variable temperature; methods using photoconductivity and photoinjection; and modeling of the degradation of MNOS structures.

  12. Single-shot compressed ultrafast photography at one hundred billion frames per second

    NASA Astrophysics Data System (ADS)

    Gao, Liang; Liang, Jinyang; Li, Chiye; Wang, Lihong V.

    2014-12-01

    The capture of transient scenes at high imaging speed has been long sought by photographers, with early examples being the well known recording in 1878 of a horse in motion and the 1887 photograph of a supersonic bullet. However, not until the late twentieth century were breakthroughs achieved in demonstrating ultrahigh-speed imaging (more than 105 frames per second). In particular, the introduction of electronic imaging sensors based on the charge-coupled device (CCD) or complementary metal-oxide-semiconductor (CMOS) technology revolutionized high-speed photography, enabling acquisition rates of up to 107 frames per second. Despite these sensors' widespread impact, further increasing frame rates using CCD or CMOS technology is fundamentally limited by their on-chip storage and electronic readout speed. Here we demonstrate a two-dimensional dynamic imaging technique, compressed ultrafast photography (CUP), which can capture non-repetitive time-evolving events at up to 1011 frames per second. Compared with existing ultrafast imaging techniques, CUP has the prominent advantage of measuring an x-y-t (x, y, spatial coordinates; t, time) scene with a single camera snapshot, thereby allowing observation of transient events with temporal resolution as tens of picoseconds. Furthermore, akin to traditional photography, CUP is receive-only, and so does not need the specialized active illumination required by other single-shot ultrafast imagers. As a result, CUP can image a variety of luminescent--such as fluorescent or bioluminescent--objects. Using CUP, we visualize four fundamental physical phenomena with single laser shots only: laser pulse reflection and refraction, photon racing in two media, and faster-than-light propagation of non-information (that is, motion that appears faster than the speed of light but cannot convey information). Given CUP's capability, we expect it to find widespread applications in both fundamental and applied sciences, including biomedical

  13. NREL Helps Clean Cities Displace Billions of Gallons of Petroleum, One Vehicle at a Time (Fact Sheet)

    SciTech Connect

    Not Available

    2010-10-01

    With more than 15 years and nearly 3 billion gallons of displaced petroleum under its belt, the Clean Cities program relies on the support and expertise of the National Renewable Energy Laboratory (NREL). An initiative of the U.S. Department of Energy (DOE), Clean Cities creates public-private partnerships with a common mission: to reduce petroleum consumption in the transportation sector. Since the inception of Clean Cities in 1993, NREL has played a central role in supporting the program, an effort that stems from the laboratory's strategy to put scientific innovation into action in the marketplace.

  14. 1.8 Billion Years of Detrital Zircon Recycling Calibrates a Refractory Part of Earth's Sedimentary Cycle.

    PubMed

    Hadlari, Thomas; Swindles, Graeme T; Galloway, Jennifer M; Bell, Kimberley M; Sulphur, Kyle C; Heaman, Larry M; Beranek, Luke P; Fallas, Karen M

    2015-01-01

    Detrital zircon studies are providing new insights on the evolution of sedimentary basins but the role of sedimentary recycling remains largely undefined. In a broad region of northwestern North America, this contribution traces the pathway of detrital zircon sand grains from Proterozoic sandstones through Phanerozoic strata and argues for multi-stage sedimentary recycling over more than a billion years. As a test of our hypothesis, integrated palynology and detrital zircon provenance provides clear evidence for erosion of Carboniferous strata in the northern Cordillera as a sediment source for Upper Cretaceous strata. Our results help to calibrate Earth's sedimentary cycle by showing that recycling dominates sedimentary provenance for the refractory mineral zircon.

  15. Electron Temperature Measurement by Floating Probe Method Using AC Voltage

    NASA Astrophysics Data System (ADS)

    Satoshi, Nodomi; Shuichi, Sato; Mikio, Ohuchi

    2016-11-01

    This study presents a novel floating probe method to measure electron temperatures using a hollow cathode-type discharge tube. The proposed method detects a shift in the floating potential when an AC voltage is applied to a probe through an intermediary blocking capacitor. The shift in the floating potential is described as a function of the electron temperature and the applied AC voltage. The floating probe method is simpler than the Langmuir probe method because it does not require the measurement of volt-ampere characteristics. As the input AC voltage increases, the electron temperature converges. The electron temperature measured using the floating probe method with an applied sinusoidal voltage shows a value close to the first (tail) electron temperature in the range of the floating potential.

  16. Evidence for global electron transportation into the jovian inner magnetosphere.

    PubMed

    Yoshioka, K; Murakami, G; Yamazaki, A; Tsuchiya, F; Kimura, T; Kagitani, M; Sakanoi, T; Uemizu, K; Kasaba, Y; Yoshikawa, I; Fujimoto, M

    2014-09-26

    Jupiter's magnetosphere is a strong particle accelerator that contains ultrarelativistic electrons in its inner part. They are thought to be accelerated by whistler-mode waves excited by anisotropic hot electrons (>10 kiloelectron volts) injected from the outer magnetosphere. However, electron transportation in the inner magnetosphere is not well understood. By analyzing the extreme ultraviolet line emission from the inner magnetosphere, we show evidence for global inward transport of flux tubes containing hot plasma. High-spectral-resolution scanning observations of the Io plasma torus in the inner magnetosphere enable us to generate radial profiles of the hot electron fraction. It gradually decreases with decreasing radial distance, despite the short collisional time scale that should thermalize them rapidly. This indicates a fast and continuous resupply of hot electrons responsible for exciting the whistler-mode waves.

  17. Titan's Spectacular Volte-Face

    NASA Astrophysics Data System (ADS)

    Griffith, Caitlin A.

    2013-10-01

    Like Earth, Titan sports lakes, storms and rainfall. These features derive from a methane cycle, reminiscent of Earth's hydrological cycle; methane exists as an ice, liquid and gas and transfers between the surface and atmosphere, according to the seasonal weather. Titan's seasons contrast Earth’s. Imagine a summer trip to 70 latitude, where hurricane-sized storms burst forth out of a clear sky every few months for about 15 years. Then they vanish for another 15 years. Envision a trip to the winter polar region. Here the sky is perhaps clear except that the high haze, which filters sunlight like a translucent globe, is somewhat thicker than it is in the summer. Imperceptibly, you are blocking the diffuse organic matter, which is slowly settling out of the hazy orb, and accumulating on the polar surface. These effects are a few of the many that derive from Titan’s circulation and its seasonal changes during the satellite's 29.5 Earth year orbit about the Sun. In particular, and as indicated in recent observations, Titan's circulation flip-flopped. Before equinox in 2009, on average, air rose in the southern polar region and downwelled in the northern polar region. Now the reverse appears to be happening. Here we discuss the observations ranging from the surface to ~500 km altitude that reveal the symphony of responses of Titan's surface and atmosphere to this dramatic shift. In addition we discuss the syntheses of these effects, from theoretical efforts involving microphysical models, local cloud models and general circulation models, with the question of why Titan's seasonal changes are so much more spectacular compared to those of Earth.

  18. An ultraluminous quasar with a twelve-billion-solar-mass black hole at redshift 6.30.

    PubMed

    Wu, Xue-Bing; Wang, Feige; Fan, Xiaohui; Yi, Weimin; Zuo, Wenwen; Bian, Fuyan; Jiang, Linhua; McGreer, Ian D; Wang, Ran; Yang, Jinyi; Yang, Qian; Thompson, David; Beletsky, Yuri

    2015-02-26

    So far, roughly 40 quasars with redshifts greater than z = 6 have been discovered. Each quasar contains a black hole with a mass of about one billion solar masses (10(9) M Sun symbol). The existence of such black holes when the Universe was less than one billion years old presents substantial challenges to theories of the formation and growth of black holes and the coevolution of black holes and galaxies. Here we report the discovery of an ultraluminous quasar, SDSS J010013.02+280225.8, at redshift z = 6.30. It has an optical and near-infrared luminosity a few times greater than those of previously known z > 6 quasars. On the basis of the deep absorption trough on the blue side of the Lyman-α emission line in the spectrum, we estimate the proper size of the ionized proximity zone associated with the quasar to be about 26 million light years, larger than found with other z > 6.1 quasars with lower luminosities. We estimate (on the basis of a near-infrared spectrum) that the black hole has a mass of ∼1.2 × 10(10) M Sun symbol, which is consistent with the 1.3 × 10(10) M Sun symbol derived by assuming an Eddington-limited accretion rate.

  19. Compound-specific carbon and hydrogen isotope analysis of sub-parts per billion level waterborne petroleum hydrocarbons

    USGS Publications Warehouse

    Wang, Y.; Huang, Y.; Huckins, J.N.; Petty, J.D.

    2004-01-01

    Compound-specific carbon and hydrogen isotope analysis (CSCIA and CSHIA) has been increasingly used to study the source, transport, and bioremediation of organic contaminants such as petroleum hydrocarbons. In natural aquatic systems, dissolved contaminants represent the bioavailable fraction that generally is of the greatest toxicological significance. However, determining the isotopic ratios of waterborne hydrophobic contaminants in natural waters is very challenging because of their extremely low concentrations (often at sub-parts ber billion, or even lower). To acquire sufficient quantities of polycyclic aromatic hydrocarbons with 10 ng/L concentration for CSHIA, more than 1000 L of water must be extracted. Conventional liquid/liquid or solid-phase extraction is not suitable for such large volume extractions. We have developed a new approach that is capable of efficiently sampling sub-parts per billion level waterborne petroleum hydrocarbons for CSIA. We use semipermeable membrane devices (SPMDs) to accumulate hydrophobic contaminants from polluted waters and then recover the compounds in the laboratory for CSIA. In this study, we demonstrate, under a variety of experimental conditions (different concentrations, temperatures, and turbulence levels), that SPMD-associated processes do not induce C and H isotopic fractionations. The applicability of SPMD-CSIA technology to natural systems is further demonstrated by determining the ??13C and ??D values of petroleum hydrocarbons present in the Pawtuxet River, RI. Our results show that the combined SPMD-CSIA is an effective tool to investigate the source and fate of hydrophobic contaminants in the aquatic environments.

  20. White Light Demonstration of One Hundred Parts per Billion Irradiance Suppression in Air by New Starshade Occulters

    NASA Technical Reports Server (NTRS)

    Levinton, Douglas B.; Cash, Webster C.; Gleason, Brian; Kaiser, Michael J.; Levine, Sara A.; Lo, Amy S.; Schindhelm, Eric; Shipley, Ann F.

    2007-01-01

    A new mission concept for the direct imaging of exo-solar planets called the New Worlds Observer (NWO) has been proposed. The concept involves flying a meter-class space telescope in formation with a newly-conceived, specially-shaped, deployable star-occulting shade several meters across at a separation of some tens of thousands of kilometers. The telescope would make its observations from behind the starshade in a volume of high suppression of incident irradiance from the star around which planets orbit. The required level of irradiance suppression created by the starshade for an efficacious mission is of order 0.1 to 10 parts per billion in broadband light. This paper discusses the experimental setup developed to accurately measure the suppression ratio of irradiance produced at the null position behind candidate starshade forms to these levels. It also presents results of broadband measurements which demonstrated suppression levels of just under 100 parts per billion in air using the Sun as a light source. Analytical modeling of spatial irradiance distributions surrounding the null are presented and compared with photographs of irradiance captured in situ behind candidate starshades.

  1. An age difference of two billion years between a metal-rich and a metal-poor globular cluster.

    PubMed

    Hansen, B M S; Kalirai, J S; Anderson, J; Dotter, A; Richer, H B; Rich, R M; Shara, M M; Fahlman, G G; Hurley, J R; King, I R; Reitzel, D; Stetson, P B

    2013-08-01

    Globular clusters trace the formation history of the spheroidal components of our Galaxy and other galaxies, which represent the bulk of star formation over the history of the Universe. The clusters exhibit a range of metallicities (abundances of elements heavier than helium), with metal-poor clusters dominating the stellar halo of the Galaxy, and higher-metallicity clusters found within the inner Galaxy, associated with the stellar bulge, or the thick disk. Age differences between these clusters can indicate the sequence in which the components of the Galaxy formed, and in particular which clusters were formed outside the Galaxy and were later engulfed along with their original host galaxies, and which were formed within it. Here we report an absolute age of 9.9 ± 0.7 billion years (at 95 per cent confidence) for the metal-rich globular cluster 47 Tucanae, determined by modelling the properties of the cluster's white-dwarf cooling sequence. This is about two billion years younger than has been inferred for the metal-poor cluster NGC 6397 from the same models, and provides quantitative evidence that metal-rich clusters like 47 Tucanae formed later than metal-poor halo clusters like NGC 6397.

  2. Earth's air pressure 2.7 billion years ago constrained to less than half of modern levels

    NASA Astrophysics Data System (ADS)

    Som, Sanjoy M.; Buick, Roger; Hagadorn, James W.; Blake, Tim S.; Perreault, John M.; Harnmeijer, Jelte P.; Catling, David C.

    2016-06-01

    How the Earth stayed warm several billion years ago when the Sun was considerably fainter is the long-standing problem of the `faint young Sun paradox'. Because of negligible O2 and only moderate CO2 levels in the Archaean atmosphere, methane has been invoked as an auxiliary greenhouse gas. Alternatively, pressure broadening in a thicker atmosphere with a N2 partial pressure around 1.6-2.4 bar could have enhanced the greenhouse effect. But fossilized raindrop imprints indicate that air pressure 2.7 billion years ago (Gyr) was below twice modern levels and probably below 1.1 bar, precluding such pressure enhancement. This result is supported by nitrogen and argon isotope studies of fluid inclusions in 3.0-3.5 Gyr rocks. Here, we calculate absolute Archaean barometric pressure using the size distribution of gas bubbles in basaltic lava flows that solidified at sea level ~2.7 Gyr in the Pilbara Craton, Australia. Our data indicate a surprisingly low surface atmospheric pressure of Patm = 0.23 +/- 0.23 (2σ) bar, and combined with previous studies suggests ~0.5 bar as an upper limit to late Archaean Patm. The result implies that the thin atmosphere was rich in auxiliary greenhouse gases and that Patm fluctuated over geologic time to a previously unrecognized extent.

  3. A spin-down clock for cool stars from observations of a 2.5-billion-year-old cluster.

    PubMed

    Meibom, Søren; Barnes, Sydney A; Platais, Imants; Gilliland, Ronald L; Latham, David W; Mathieu, Robert D

    2015-01-29

    The ages of the most common stars--low-mass (cool) stars like the Sun, and smaller--are difficult to derive because traditional dating methods use stellar properties that either change little as the stars age or are hard to measure. The rotation rates of all cool stars decrease substantially with time as the stars steadily lose their angular momenta. If properly calibrated, rotation therefore can act as a reliable determinant of their ages based on the method of gyrochronology. To calibrate gyrochronology, the relationship between rotation period and age must be determined for cool stars of different masses, which is best accomplished with rotation period measurements for stars in clusters with well-known ages. Hitherto, such measurements have been possible only in clusters with ages of less than about one billion years, and gyrochronology ages for older stars have been inferred from model predictions. Here we report rotation period measurements for 30 cool stars in the 2.5-billion-year-old cluster NGC 6819. The periods reveal a well-defined relationship between rotation period and stellar mass at the cluster age, suggesting that ages with a precision of order 10 per cent can be derived for large numbers of cool Galactic field stars.

  4. A handful of 'antipoverty' vaccines exist for neglected diseases, but the world's poorest billion people need more.

    PubMed

    Hotez, Peter

    2011-06-01

    So-called neglected tropical diseases are the most common infections of the world's poor. Almost all of the "bottom billion"--the 1.4 billion people who live below the poverty level defined by the World Bank--suffer from one or more neglected diseases including hookworm infection, sleeping sickness, or Chagas disease. These diseases are actually a cause of poverty because of their adverse effects on child growth and development and worker productivity. Vaccines to combat such diseases have come to be known as "antipoverty vaccines." Unfortunately, the recent surge in the development and delivery of vaccines to combat the major childhood killers--such as pneumococcal pneumonia and measles--has bypassed neglected diseases. Nevertheless, some vaccines for these neglected diseases are now entering the clinical pipeline. In this article I describe how some antipoverty vaccine development is proceeding and offer recommendations for stimulating further development such as through pooled funding for innovation, developing-country manufacturers, and public-private partnerships for product development.

  5. Multi-petahertz electronic metrology.

    PubMed

    Garg, M; Zhan, M; Luu, T T; Lakhotia, H; Klostermann, T; Guggenmos, A; Goulielmakis, E

    2016-10-20

    The frequency of electric currents associated with charge carriers moving in the electronic bands of solids determines the speed limit of electronics and thereby that of information and signal processing. The use of light fields to drive electrons promises access to vastly higher frequencies than conventionally used, as electric currents can be induced and manipulated on timescales faster than that of the quantum dephasing of charge carriers in solids. This forms the basis of terahertz (10(12) hertz) electronics in artificial superlattices, and has enabled light-based switches and sampling of currents extending in frequency up to a few hundred terahertz. Here we demonstrate the extension of electronic metrology to the multi-petahertz (10(15) hertz) frequency range. We use single-cycle intense optical fields (about one volt per ångström) to drive electron motion in the bulk of silicon dioxide, and then probe its dynamics by using attosecond (10(-18) seconds) streaking to map the time structure of emerging isolated attosecond extreme ultraviolet transients and their optical driver. The data establish a firm link between the emission of the extreme ultraviolet radiation and the light-induced intraband, phase-coherent electric currents that extend in frequency up to about eight petahertz, and enable access to the dynamic nonlinear conductivity of silicon dioxide. Direct probing, confinement and control of the waveform of intraband currents inside solids on attosecond timescales establish a method of realizing multi-petahertz coherent electronics. We expect this technique to enable new ways of exploring the interplay between electron dynamics and the structure of condensed matter on the atomic scale.

  6. Multi-petahertz electronic metrology

    NASA Astrophysics Data System (ADS)

    Garg, M.; Zhan, M.; Luu, T. T.; Lakhotia, H.; Klostermann, T.; Guggenmos, A.; Goulielmakis, E.

    2016-10-01

    The frequency of electric currents associated with charge carriers moving in the electronic bands of solids determines the speed limit of electronics and thereby that of information and signal processing. The use of light fields to drive electrons promises access to vastly higher frequencies than conventionally used, as electric currents can be induced and manipulated on timescales faster than that of the quantum dephasing of charge carriers in solids. This forms the basis of terahertz (1012 hertz) electronics in artificial superlattices, and has enabled light-based switches and sampling of currents extending in frequency up to a few hundred terahertz. Here we demonstrate the extension of electronic metrology to the multi-petahertz (1015 hertz) frequency range. We use single-cycle intense optical fields (about one volt per ångström) to drive electron motion in the bulk of silicon dioxide, and then probe its dynamics by using attosecond (10-18 seconds) streaking to map the time structure of emerging isolated attosecond extreme ultraviolet transients and their optical driver. The data establish a firm link between the emission of the extreme ultraviolet radiation and the light-induced intraband, phase-coherent electric currents that extend in frequency up to about eight petahertz, and enable access to the dynamic nonlinear conductivity of silicon dioxide. Direct probing, confinement and control of the waveform of intraband currents inside solids on attosecond timescales establish a method of realizing multi-petahertz coherent electronics. We expect this technique to enable new ways of exploring the interplay between electron dynamics and the structure of condensed matter on the atomic scale.

  7. Near-threshold emission of electrons during grazing scattering of keV Ne atoms from an Al(111) surface

    SciTech Connect

    Matulevich, Y.; Lederer, S.; Winter, H.

    2005-01-15

    The number of electrons emitted during grazing scattering of Ne atoms with kilo-electron-volt energies from an Al(111) surface is recorded in coincidence with the energy loss of scattered projectiles. Irrespective of the total projectile energies used, we observe a pronounced increase of total electron emission yields when the energy for motion normal to the surface exceeds about 25 eV. Based on energy loss spectra and classical computer simulations of projectile trajectories we attribute electron emission under these scattering conditions to a promotion mechanism in binary collisions between Ne and Al target atoms resulting in single and double excitations of projectiles.

  8. 405th Brookhaven Lecture

    SciTech Connect

    Vadim Ptitsyn

    2005-06-22

    "E-RHIC - Future Electron-Ion Collider at BNL. While RHIC scientists continue their quest to look deep into nuclear phenomena resulting from collisions of ion beams and beams of polarized protons, new design work is under way for a possible extension of RHIC to include e-RHIC, a 10-billion electron volt, high-intensity polarized proton beam.

  9. 405th Brookhaven Lecture

    ScienceCinema

    Vadim Ptitsyn

    2016-07-12

    "E-RHIC - Future Electron-Ion Collider at BNL. While RHIC scientists continue their quest to look deep into nuclear phenomena resulting from collisions of ion beams and beams of polarized protons, new design work is under way for a possible extension of RHIC to include e-RHIC, a 10-billion electron volt, high-intensity polarized proton beam.

  10. A Business Case for Electronic Commerce

    DTIC Science & Technology

    1990-09-01

    Electronic Commerce . This report presents the results of that examination. Based upon an examination of 16 key documents, we estimate that DoD could realize direct and indirect cost savings of almost $1.2 billion over a 10-year period by replacing these manually processed documents with their electronic equivalents. To achieve those savings, DoD would need to make investments totaling approximately $80 million in new systems and procedures. (Author)

  11. How Measuring the Planck Constant gets to an Electronic Kilogram Standard

    SciTech Connect

    Steiner, Richard

    2007-08-01

    The best measurement of the Planck constant is now derived from the watt balance method. This method measures mechanical power, in reference units of the kilogram (artifact mass standard), second (atomic clocks), and meter (lasers), in ratio to electrical power, in reference units of the volt (Josephson effect) and ohm (quantum Hall effect). Of these reference standards, only the kilogram is still an artifact standard. Thus a high precision measurement of the Planck constant is equivalent to monitoring the SI kilogram artifact, and may be used to redefine the kilogram. This talk will summarize the complexity of making a Planck constant measurement, where there are interesting aspects of basic physics that appear when the ultimate precision of the standards laboratory is applied to obtain an uncertainty of 20 parts in a billion.

  12. Electron transfer, ionization, and excitation in atomic collisions. Progress report, June 15, 1992--June 14, 1995

    SciTech Connect

    Winter, T.G.; Alston, S.G.

    1995-08-01

    The research program of Winter and Alston addresses the fundamental processes of electron transfer, ionization, and excitation in ion-atom, ion-ion, and ion-molecule collisions. Attention is focussed on one- and two-electron systems and, more recently, quasi-one-electron systems whose electron-target-core interaction can be accurately modeled by one-electron potentials. The basic computational approaches can then be taken with few, if any, approximations, and the underlying collisional mechanisms can be more clearly revealed. Winter has focussed on intermediate collision energies (e.g., proton energies for p-He{sup +} collisions on the order of 100 kilo-electron volts), in which many electron states are strongly coupled during the collision and a coupled-state approach, such as a coupled-Sturmian-pseudostate approach, is appropriate. Alston has concentrated on higher collision energies (million electron-volt energies), or asymmetric collision systems, for which the coupling of the projectile is weaker with, however, many more target states being coupled together so that high-order perturbation theory is essential. Several calculations by Winter and Alston are described, as set forth in the original proposal.

  13. Taking out one billion tones of carbon: the magic of China's 11thFive-Year Plan

    SciTech Connect

    Lin, Jiang; Zhou, Nan; Levine, Mark D.; Fridley, David

    2007-05-01

    China's 11th Five-Year Plan (FYP) sets an ambitious targetfor energy-efficiency improvement: energy intensity of the country sgross domestic product (GDP) should be reduced by 20 percent from 2005 to2010 (NDRC, 2006). This is the first time that a quantitative and bindingtarget has been set for energy efficiency, and signals a major shift inChina's strategic thinking about its long-term economic and energydevelopment. The 20 percent energy intensity target also translates intoan annual reduction of over one billion tons of CO2 by 2010, making theChinese effort one of most significant carbon mitigation effort in theworld today. While it is still too early to tell whether China willachieve this target, this paper attempts to understand the trend inenergy intensity in China and to explore a variety of options towardmeeting the 20 percent target using a detailed endues energymodel.

  14. Vaccine Assistance To Low- And Middle-Income Countries Increased To $3.6 Billion In 2014.

    PubMed

    Haakenstad, Annie; Birger, Maxwell; Singh, Lavanya; Liu, Patrick; Lim, Stephen; Ng, Marie; Dieleman, Joseph L

    2016-02-01

    In the 2012 Global Vaccine Action Plan, development assistance partners committed to providing sustainable financing for vaccines and expanding vaccination coverage to all children in low- and middle-income countries by 2020. To assess progress toward these goals, the Institute for Health Metrics and Evaluation produced estimates of development assistance for vaccinations. These estimates reveal major increases in the assistance provided since 2000. In 2014, $3.6 billion in development assistance for vaccinations was provided for low- and middle-income countries, up from $822 million in 2000. The funding increase was driven predominantly by the establishment of Gavi, the Vaccine Alliance, supported by the Bill & Melinda Gates Foundation and the governments of the United States and United Kingdom. Despite stagnation in total development assistance for health from donors from 2010 onward, development assistance for vaccination has continued to grow.

  15. United States menhaden oil could save billions in U.S. health care costs and improve IQ in children.

    PubMed

    Bibus, Douglas M

    2016-02-01

    The United States menhaden oil annual production is sufficient to supply all of the recommended long chain Omega-3s for Americans over 55 with coronary heart disease (CHD) and pregnant and lactating women. According to a recent study, the utilization of preventable intake levels could potentially save up to $1.7 billion annually in hospital costs alone. In addition, the remaining oil could be used to support a culture of enough Atlantic salmon to provide every pregnant and lactating woman in the U.S. with 8-12 ounces of fish per week, as recommended by the Food and Drug Administration (FDA), throughout the duration of pregnancy and lactation. Based on the FDA's quantitative assessment, this may result in a net increase of IQ by 5.5 points in children and improve their early age verbal development.

  16. The Archean Dongwanzi ophiolite complex, North China craton: 2.505-billion-year-old oceanic crust and mantle.

    PubMed

    Kusky, T M; Li, J H; Tucker, R D

    2001-05-11

    We report a thick, laterally extensive 2505 +/- 2.2-million-year-old (uranium-lead ratio in zircon) Archean ophiolite complex in the North China craton. Basal harzburgite tectonite is overlain by cumulate ultramafic rocks, a mafic-ultramafic transition zone of interlayered gabbro and ultramafic cumulates, compositionally layered olivine-gabbro and pyroxenite, and isotropic gabbro. A sheeted dike complex is rooted in the gabbro and overlain by a mixed dike-pillow lava section, chert, and banded iron formation. The documentation of a complete Archean ophiolite implies that mechanisms of oceanic crustal accretion similar to those of today were in operation by 2.5 billion years ago at divergent plate margins and that the temperature of the early mantle was not extremely elevated, as compared to the present-day temperature. Plate tectonic processes similar to those of the present must also have emplaced the ophiolite in a convergent margin setting.

  17. 1.8 Billion Years of Detrital Zircon Recycling Calibrates a Refractory Part of Earth’s Sedimentary Cycle

    PubMed Central

    Hadlari, Thomas; Swindles, Graeme T.; Galloway, Jennifer M.; Bell, Kimberley M.; Sulphur, Kyle C.; Heaman, Larry M.; Beranek, Luke P.; Fallas, Karen M.

    2015-01-01

    Detrital zircon studies are providing new insights on the evolution of sedimentary basins but the role of sedimentary recycling remains largely undefined. In a broad region of northwestern North America, this contribution traces the pathway of detrital zircon sand grains from Proterozoic sandstones through Phanerozoic strata and argues for multi-stage sedimentary recycling over more than a billion years. As a test of our hypothesis, integrated palynology and detrital zircon provenance provides clear evidence for erosion of Carboniferous strata in the northern Cordillera as a sediment source for Upper Cretaceous strata. Our results help to calibrate Earth's sedimentary cycle by showing that recycling dominates sedimentary provenance for the refractory mineral zircon. PMID:26658165

  18. Taking out 1 billion tons of CO2: The magic of China's 11th Five-Year Plan?

    SciTech Connect

    Zhou, Nan; Lin, Jiang; Zhou, Nan; Levine, Mark; Fridley, David

    2007-07-01

    China's 11th Five-Year Plan (FYP) sets an ambitious target for energy-efficiency improvement: energy intensity of the country's gross domestic product (GDP) should be reduced by 20% from 2005 to 2010 (NDRC, 2006). This is the first time that a quantitative and binding target has been set for energy efficiency, and signals a major shift in China's strategic thinking about its long-term economic and energy development. The 20% energy intensity target also translates into an annual reduction of over 1.5 billion tons of CO2 by 2010, making the Chinese effort one of most significant carbon mitigation effort in the world today. While it is still too early to tell whether China will achieve this target, this paper attempts to understand the trend in energy intensity in China and to explore a variety of options toward meeting the 20% target using a detailed end-use energy model.

  19. CETA's $11 Billion

    ERIC Educational Resources Information Center

    Hersher, Judy

    1978-01-01

    The Comprehensive Employment and Training Act (CETA) is now before Congress for review and reenactment. This article examines previous CETA program efforts and the new provisions intended to target jobs and training to the most disadvantaged in terms of income and length of unemployment. (Author/AM)

  20. Developing a Billion Leaders

    ERIC Educational Resources Information Center

    Gergen, Christopher; Rego, Lyndon; Wright, Joel

    2014-01-01

    Intentionally developing the leadership capacity of all students is a necessary requirement for schools around the world. The Center for Creative Leadership in Greensboro, N.C., has been at the center of this work and presents three schools as examples: Ravenscroft School in Raleigh, N.C., the African Leadership Academy in Johannesburg, South…

  1. CESR Conversion Damping Ring Studies of Electron Cloud Instabilities (CESR-TA)

    SciTech Connect

    Rubin, David L.; Palmer, Mark A.

    2011-08-02

    In the International Linear Collider, two linear accelerators will accelerate bunches of positrons and electrons to over a hundred billion electron volts and collide them in a central detector. In order to obtain useful collision rates, the bunches, each containing twenty billion particles, must be compressed to a cross section of a few nanometers by a few hundred nanometers. In order to prepare these ultra high density bunches, damping rings (DRs) are employed before the linear accelerators. The DRs take the high emittance bunches that are provided by the electron and positron sources and, through the process of radiation damping, squeeze them into ultra low emittance beams that are ready for the main linear accelerators. In the damping rings, a number of effects can prevent the successful preparation of the beams. In the electron ring, an effect known as the fast ion instability can lead to beam growth and, in the positron ring, the build-up of an electron cloud (EC), which interacts with the circulating bunches, can produce the same effect. EC build-up and the subsequent interaction of the cloud with the positron beam in the DR have been identified as major risks for the successful construction of a linear collider. The CESRTA research program at the Cornell Electron Storage Ring (CESR) was developed in order to study the build-up of the EC, the details of its impact on ultra low emittance beams, as well as methods to mitigate the impact of the cloud. In the DR, the EC forms when synchrotron photons radiated from the circulating beam strike the walls of the vacuum chamber, resulting in the emission of photoelectrons. These low energy electrons can be accelerated across the vacuum chamber by the electric field of the beam, and strike the walls, causing the emission of secondary electrons. The secondary electrons are subsequently accelerated into the walls yet again via the same mechanism. The result is that the EC can rapidly begin to fill the vacuum chamber. In

  2. Preliminary tests of vulnerability of typical aircraft electronics to lightning-induced voltages

    NASA Technical Reports Server (NTRS)

    Plumer, J. A.; Walko, L. C.

    1974-01-01

    Tests made on two pieces of typical aircraft electronics equipment to ascertain their vulnerability to simulated lightning-induced transient voltages representative of those which might occur in flight when the aircraft is struck by lightning were conducted. The test results demonstrated that such equipment can be interfered with or damaged by transient voltages as low as 21 volts peak. Greater voltages can cause failure of semiconductor components within the equipment. The results emphasize a need for establishment of coordinated system susceptibility and component vulnerability criteria to achieve lightning protection of aerospace electrical and electronic systems.

  3. Lamellar magnetism and exchange bias in billion-year-old titanohematite with nanoscale ilmenite exsolution lamellae: I. Mineral and magnetic characterization

    NASA Astrophysics Data System (ADS)

    McEnroe, Suzanne A.; Robinson, Peter; Miyajima, Nobuyoshi; Fabian, Karl; Dyar, Darby; Sklute, Elizabeth

    2016-07-01

    Recent high-resolution aeromagnetic surveys in South Norway have revealed numerous remanent anomalies over Mesoproterozoic metamorphic rocks. Studies on the nature of the minerals that are the remanent carriers has led to discoveries of titanohematite samples with unusual magnetic properties caused by nanoscale exsolution lamellae with their related lamellar magnetism. Here we focus on a rock unit dominated by quartz-plagioclase-biotite granulite containing titanohematite grains with a strong lattice-preferred orientation parallel to regional foliation. When samples with their natural remanent magnetization (NRM), acquired nearly 1 billion years ago, are cooled to 10 K and hysteresis loops measured, these loops show bi-modal exchange bias caused by the magnetism induced within the ilmenite by antiferromagnetic coupling with the adjacent lamellar NRM. By contrast when the samples are cooled in a strong magnetic field (1.5 Tesla), this results in unimodal lamellar magnetism, and, below the TN of ilmenite it adopts a consistent negative orientation, giving rise to unimodal negative exchange bias of >500 mT. The results presented here cover the chemical and magnetic properties, Mossbauer results and transmission electron microscopy of the titanohematite and ilmenite lamellae. Initial magnetic experiments indicated the shifts found in the exchange-bias experiments were directly related to the orientation of the sample to the applied field and the initial state of the NRM. In most samples with these unusual magnetic properties, ilmenite lamellae could not be seen in an optical or a scanning electron microscope. However magnetic experiments gave proof of the presence of ilmenite, later confirmed by Mössbauer spectroscopy. Several attempts were made to identify ilmenite in TEM studies, finally successful in showing ilmenite lamellae parallel to (001) of hematite with thicknesses ˜1.2 to 1.7 nm and aspect ratios 7-13. Here we compare new TEM images and the magnetic

  4. A One Billion Year Martian Climate Model: The Importance of Seasonally Resolved Polar Caps and the Role of Wind

    NASA Technical Reports Server (NTRS)

    Armstrong, J. C.; Leovy, C. B.; Quinn, T. R.; Haberle, R. M.; Schaeffer, J.

    2003-01-01

    Wind deflation and deposition are powerful agents of surface change in the present Mars climate regime. Recent studies indicate that, while the distribution of regions of potential deflation (or erosion) and deposition is remarkably insensitive to changes in orbital parameters (obliquity, timing of perihelion passage, etc.), rates of aeolian surface modification may be highly sensitive to these parameters even if the atmospheric mass remains constant. But previous work suggested the atmospheric mass is likely to be sensitive to obliquity, especially if a significant mass of carbon dioxide can be stored in the regolith or deposited in the form of massive polar caps. Deflation and erosion are highly sensitive to surface pressure, so feedback between orbit variations and surface pressure can greatly enhance the sensitivity of aeolian modification rates to orbital parameters. We used statistics derived from a 1 Gyr orbital integration of the spin axis of Mars, coupled with 3D general circulation models (GCMs) at a variety of orbital conditions and pressures, to explore this feedback. We also employed a seasonally resolved 1D energy balance model to illuminate the gross characteristics of the longterm atmospheric evolution, wind erosion and deposition over one billion years. We find that seasonal polar cycles have a critical influence on the ability for the regolith to release CO2 at high obliquities, and find that the atmospheric CO2 actually decreases at high obliquities due to the cooling effect of polar deposits at latitudes where seasonal caps form. At low obliquity, the formation of massive, permanent polar caps depends critically on the values of the frost albedo, A(sub frost), and frost emissivity, E(sub frost). Using our 1D model with values of A(sub frost) = 0.67 and E(sub frost) = 0.55, matched to the NASA Ames GCM results, we find that permanent caps only form at low obliquities (< 10 degrees). Thus, contrary to expectations, the Martian atmospheric pressure

  5. Electronic, magnetic, and geometric structure of metallo-carbohedrenes

    SciTech Connect

    Reddy, B.V.; Khanna, S.N.; Jena, P. )

    1992-12-04

    The energetics and the electronic, magnetic, and geometric structure of the metallocarbohedrene Ti[sub 8]C[sub 12] have been calculated self-consistently in the density functional formulation. The structure of Ti[sub 8]C[sub 12] is a distorted dodecahedron with a binding energy of 6.1 electron volts per atom. The unusual stability is derived from covalent-like bonding between carbon atoms and between titanium and carbon atoms with no appreciable interaction between titanium atoms. The density of states at the Fermi energy is high and is derived from a strong hybridization between titanium 3d and carbon sp electrons. Titanium sites carry a small magnetic moment of 0.35 Bohr magneton per atom and the cluster is only weakly magnetic. 13 refs., 3 figs., 1 tab.

  6. Observations of Energetic Ions and Electrons in Saturn's Magnetosphere.

    PubMed

    Trainor, J H; McDonald, F B; Schardt, A W

    1980-01-25

    The passage of Pioneer 11 by Saturn provided a detailed view of a planetary magnetosphere that is intermediate between those of Jupiter and Earth in both scale and the complexity of its dynamic processes. It appears to have at least three distinct regions: (i) an outer magnetosphere, extending from 17 to 7.5 Saturn radii, that resembles that of Earth in many important aspects; (ii) a slot region, between 7.5 and 4 Saturn radii, where a marked decrease in all protons and low-energy electrons is observed; and (iii) an inner region, extending from 4 Saturn radii to the ring edge, that features a sharp increase in the proton flux extending to energies greater than 20 million electron volts. A cutoff of both proton and electron fluxes occurred just beyond the nominal edge of the A ring.

  7. A large population of galaxies 9 to 12 billion years back in the history of the Universe

    NASA Astrophysics Data System (ADS)

    Le Fèvre, O.; Paltani, S.; Arnouts, S.; Charlot, S.; Foucaud, S.; Ilbert, O.; McCracken, H. J.; Zamorani, G.; Bottini, D.; Garilli, B.; Le Brun, V.; Maccagni, D.; Picat, J. P.; Scaramella, R.; Scodeggio, M.; Tresse, L.; Vettolani, G.; Zanichelli, A.; Adami, C.; Bardelli, S.; Bolzonella, M.; Cappi, A.; Ciliegi, P.; Contini, T.; Franzetti, P.; Gavignaud, I.; Guzzo, L.; Iovino, A.; Marano, B.; Marinoni, C.; Mazure, A.; Meneux, B.; Merighi, R.; Pellò, R.; Pollo, A.; Pozzetti, L.; Radovich, M.; Zucca, E.; Arnaboldi, M.; Bondi, M.; Bongiorno, A.; Busarello, G.; Gregorini, L.; Lamareille, F.; Mathez, G.; Mellier, Y.; Merluzzi, P.; Ripepi, V.; Rizzo, D.

    2005-09-01

    To understand the evolution of galaxies, we need to know as accurately as possible how many galaxies were present in the Universe at different epochs. Galaxies in the young Universe have hitherto mainly been identified using their expected optical colours, but this leaves open the possibility that a significant population remains undetected because their colours are the result of a complex mix of stars, gas, dust or active galactic nuclei. Here we report the results of a flux-limited I-band survey of galaxies at look-back times of 9 to 12 billion years. We find 970 galaxies with spectroscopic redshifts between 1.4 and 5. This population is 1.6 to 6.2 times larger than previous estimates, with the difference increasing towards brighter magnitudes. Strong ultraviolet continua (in the rest frame of the galaxies) indicate vigorous star formation rates of more than 10-100 solar masses per year. As a consequence, the cosmic star formation rate representing the volume-averaged production of stars is higher than previously measured at redshifts of 3 to 4.

  8. Organic-walled microfossils in 3.2-billion-year-old shallow-marine siliciclastic deposits.

    PubMed

    Javaux, Emmanuelle J; Marshall, Craig P; Bekker, Andrey

    2010-02-18

    Although the notion of an early origin and diversification of life on Earth during the Archaean eon has received increasing support in geochemical, sedimentological and palaeontological evidence, ambiguities and controversies persist regarding the biogenicity and syngeneity of the record older than Late Archaean. Non-biological processes are known to produce morphologies similar to some microfossils, and hydrothermal fluids have the potential to produce abiotic organic compounds with depleted carbon isotope values, making it difficult to establish unambiguous traces of life. Here we report the discovery of a population of large (up to about 300 mum in diameter) carbonaceous spheroidal microstructures in Mesoarchaean shales and siltstones of the Moodies Group, South Africa, the Earth's oldest siliciclastic alluvial to tidal-estuarine deposits. These microstructures are interpreted as organic-walled microfossils on the basis of petrographic and geochemical evidence for their endogenicity and syngeneity, their carbonaceous composition, cellular morphology and ultrastructure, occurrence in populations, taphonomic features of soft wall deformation, and the geological context plausible for life, as well as a lack of abiotic explanation falsifying a biological origin. These are the oldest and largest Archaean organic-walled spheroidal microfossils reported so far. Our observations suggest that relatively large microorganisms cohabited with earlier reported benthic microbial mats in the photic zone of marginal marine siliciclastic environments 3.2 billion years ago.

  9. Sulfur isotopes of organic matter preserved in 3.45-billion-year-old stromatolites reveal microbial metabolism.

    PubMed

    Bontognali, Tomaso R R; Sessions, Alex L; Allwood, Abigail C; Fischer, Woodward W; Grotzinger, John P; Summons, Roger E; Eiler, John M

    2012-09-18

    The 3.45-billion-year-old Strelley Pool Formation of Western Australia preserves stromatolites that are considered among the oldest evidence for life on Earth. In places of exceptional preservation, these stromatolites contain laminae rich in organic carbon, interpreted as the fossil remains of ancient microbial mats. To better understand the biogeochemistry of these rocks, we performed microscale in situ sulfur isotope measurements of the preserved organic sulfur, including both Δ(33)S and . This approach allows us to tie physiological inference from isotope ratios directly to fossil biomass, providing a means to understand sulfur metabolism that is complimentary to, and independent from, inorganic proxies (e.g., pyrite). Δ(33)S values of the kerogen reveal mass-anomalous fractionations expected of the Archean sulfur cycle, whereas values show large fractionations at very small spatial scales, including values below -15‰. We interpret these isotopic patterns as recording the process of sulfurization of organic matter by H(2)S in heterogeneous mat pore-waters influenced by respiratory S metabolism. Positive Δ(33)S anomalies suggest that disproportionation of elemental sulfur would have been a prominent microbial process in these communities.

  10. Decimetre-scale multicellular eukaryotes from the 1.56-billion-year-old Gaoyuzhuang Formation in North China

    PubMed Central

    Zhu, Shixing; Zhu, Maoyan; Knoll, Andrew H.; Yin, Zongjun; Zhao, Fangchen; Sun, Shufen; Qu, Yuangao; Shi, Min; Liu, Huan

    2016-01-01

    Fossils of macroscopic eukaryotes are rarely older than the Ediacaran Period (635–541 million years (Myr)), and their interpretation remains controversial. Here, we report the discovery of macroscopic fossils from the 1,560-Myr-old Gaoyuzhuang Formation, Yanshan area, North China, that exhibit both large size and regular morphology. Preserved as carbonaceous compressions, the Gaoyuzhuang fossils have statistically regular linear to lanceolate shapes up to 30 cm long and nearly 8 cm wide, suggesting that the Gaoyuzhuang fossils record benthic multicellular eukaryotes of unprecedentedly large size. Syngenetic fragments showing closely packed ∼10 μm cells arranged in a thick sheet further reinforce the interpretation. Comparisons with living thalloid organisms suggest that these organisms were photosynthetic, although their phylogenetic placement within the Eukarya remains uncertain. The new fossils provide the strongest evidence yet that multicellular eukaryotes with decimetric dimensions and a regular developmental program populated the marine biosphere at least a billion years before the Cambrian Explosion. PMID:27186667

  11. The economic downturn and its lingering effects reduced medicare spending growth by $4 billion in 2009-12.

    PubMed

    Dranove, David; Garthwaite, Craig; Ody, Christopher

    2015-08-01

    Previous work has found a strong connection between the most recent economic recession and reductions in private health spending. However, the effect of economic downturns on Medicare spending is less clear. In contrast to studies involving earlier time periods, our study found that when the macroeconomy slowed during the Great Recession of 2007-09, so did Medicare spending growth. A small (14 percent) but significant share of the decline in Medicare spending growth from 2009 to 2012 relative to growth from 2004 to 2009 can be attributed to lingering effects of the recession. Absent the economic downturn, Medicare spending would have been $4 billion higher in 2009-12. A major reason for the relatively small impact of the macroeconomy is the relative lack of labor-force participation among people ages sixty-five and older. We estimate that if they had been working at the same rate as the nonelderly before the recession, the effect of the downturn on Medicare spending growth would have been twice as large.

  12. Malthus is still wrong: we can feed a world of 9-10 billion, but only by reducing food demand.

    PubMed

    Smith, Pete

    2015-08-01

    In 1798, Thomas Robert Malthus published 'An essay on the principle of population' in which he concluded that: 'The power of population is so superior to the power of the earth to produce subsistence for man, that premature death must in some shape or other visit the human race.' Over the following century he was criticised for underestimating the potential for scientific and technological innovation to provide positive change. Since then, he has been proved wrong, with a number of papers published during the past few decades pointing out why he has been proved wrong so many times. In the present paper, I briefly review the main changes in food production in the past that have allowed us to continue to meet ever growing demand for food, and I examine the possibility of these same innovations delivering food security in the future. On the basis of recent studies, I conclude that technological innovation can no longer be relied upon to prove Malthus wrong as we strive to feed 9-10 billion people by 2050. Unless we are prepared to accept a wide range of significant, undesirable environmental consequences, technology alone cannot provide food security in 2050. Food demand, particularly the demand for livestock products, will need to be managed if we are to continue to prove Malthus wrong into the future.

  13. Decimetre-scale multicellular eukaryotes from the 1.56-billion-year-old Gaoyuzhuang Formation in North China.

    PubMed

    Zhu, Shixing; Zhu, Maoyan; Knoll, Andrew H; Yin, Zongjun; Zhao, Fangchen; Sun, Shufen; Qu, Yuangao; Shi, Min; Liu, Huan

    2016-05-17

    Fossils of macroscopic eukaryotes are rarely older than the Ediacaran Period (635-541 million years (Myr)), and their interpretation remains controversial. Here, we report the discovery of macroscopic fossils from the 1,560-Myr-old Gaoyuzhuang Formation, Yanshan area, North China, that exhibit both large size and regular morphology. Preserved as carbonaceous compressions, the Gaoyuzhuang fossils have statistically regular linear to lanceolate shapes up to 30 cm long and nearly 8 cm wide, suggesting that the Gaoyuzhuang fossils record benthic multicellular eukaryotes of unprecedentedly large size. Syngenetic fragments showing closely packed ∼10 μm cells arranged in a thick sheet further reinforce the interpretation. Comparisons with living thalloid organisms suggest that these organisms were photosynthetic, although their phylogenetic placement within the Eukarya remains uncertain. The new fossils provide the strongest evidence yet that multicellular eukaryotes with decimetric dimensions and a regular developmental program populated the marine biosphere at least a billion years before the Cambrian Explosion.

  14. Sulfur isotopes of organic matter preserved in 3.45-billion-year-old stromatolites reveal microbial metabolism

    PubMed Central

    Bontognali, Tomaso R. R.; Sessions, Alex L.; Allwood, Abigail C.; Fischer, Woodward W.; Grotzinger, John P.; Summons, Roger E.; Eiler, John M.

    2012-01-01

    The 3.45-billion-year-old Strelley Pool Formation of Western Australia preserves stromatolites that are considered among the oldest evidence for life on Earth. In places of exceptional preservation, these stromatolites contain laminae rich in organic carbon, interpreted as the fossil remains of ancient microbial mats. To better understand the biogeochemistry of these rocks, we performed microscale in situ sulfur isotope measurements of the preserved organic sulfur, including both Δ33S and . This approach allows us to tie physiological inference from isotope ratios directly to fossil biomass, providing a means to understand sulfur metabolism that is complimentary to, and independent from, inorganic proxies (e.g., pyrite). Δ33S values of the kerogen reveal mass-anomalous fractionations expected of the Archean sulfur cycle, whereas values show large fractionations at very small spatial scales, including values below -15‰. We interpret these isotopic patterns as recording the process of sulfurization of organic matter by H2S in heterogeneous mat pore-waters influenced by respiratory S metabolism. Positive Δ33S anomalies suggest that disproportionation of elemental sulfur would have been a prominent microbial process in these communities. PMID:22949693

  15. The rapid assembly of an elliptical galaxy of 400 billion solar masses at a redshift of 2.3.

    PubMed

    Fu, Hai; Cooray, Asantha; Feruglio, C; Ivison, R J; Riechers, D A; Gurwell, M; Bussmann, R S; Harris, A I; Altieri, B; Aussel, H; Baker, A J; Bock, J; Boylan-Kolchin, M; Bridge, C; Calanog, J A; Casey, C M; Cava, A; Chapman, S C; Clements, D L; Conley, A; Cox, P; Farrah, D; Frayer, D; Hopwood, R; Jia, J; Magdis, G; Marsden, G; Martínez-Navajas, P; Negrello, M; Neri, R; Oliver, S J; Omont, A; Page, M J; Pérez-Fournon, I; Schulz, B; Scott, D; Smith, A; Vaccari, M; Valtchanov, I; Vieira, J D; Viero, M; Wang, L; Wardlow, J L; Zemcov, M

    2013-06-20

    Stellar archaeology shows that massive elliptical galaxies formed rapidly about ten billion years ago with star-formation rates of above several hundred solar masses per year. Their progenitors are probably the submillimetre bright galaxies at redshifts z greater than 2. Although the mean molecular gas mass (5 × 10(10) solar masses) of the submillimetre bright galaxies can explain the formation of typical elliptical galaxies, it is inadequate to form elliptical galaxies that already have stellar masses above 2 × 10(11) solar masses at z ≈ 2. Here we report multi-wavelength high-resolution observations of a rare merger of two massive submillimetre bright galaxies at z = 2.3. The system is seen to be forming stars at a rate of 2,000 solar masses per year. The star-formation efficiency is an order of magnitude greater than that of normal galaxies, so the gas reservoir will be exhausted and star formation will be quenched in only around 200 million years. At a projected separation of 19 kiloparsecs, the two massive starbursts are about to merge and form a passive elliptical galaxy with a stellar mass of about 4 × 10(11) solar masses. We conclude that gas-rich major galaxy mergers with intense star formation can form the most massive elliptical galaxies by z ≈ 1.5.

  16. A large population of galaxies 9 to 12 billion years back in the history of the Universe.

    PubMed

    Le Fèvre, O; Paltani, S; Arnouts, S; Charlot, S; Foucaud, S; Ilbert, O; McCracken, H J; Zamorani, G; Bottini, D; Garilli, B; Le Brun, V; Maccagni, D; Picat, J P; Scaramella, R; Scodeggio, M; Tresse, L; Vettolani, G; Zanichelli, A; Adami, C; Bardelli, S; Bolzonella, M; Cappi, A; Ciliegi, P; Contini, T; Franzetti, P; Gavignaud, I; Guzzo, L; Iovino, A; Marano, B; Marinoni, C; Mazure, A; Meneux, B; Merighi, R; Pellò, R; Pollo, A; Pozzetti, L; Radovich, M; Zucca, E; Arnaboldi, M; Bondi, M; Bongiorno, A; Busarello, G; Gregorini, L; Lamareille, F; Mathez, G; Mellier, Y; Merluzzi, P; Ripepi, V; Rizzo, D

    2005-09-22

    To understand the evolution of galaxies, we need to know as accurately as possible how many galaxies were present in the Universe at different epochs. Galaxies in the young Universe have hitherto mainly been identified using their expected optical colours, but this leaves open the possibility that a significant population remains undetected because their colours are the result of a complex mix of stars, gas, dust or active galactic nuclei. Here we report the results of a flux-limited I-band survey of galaxies at look-back times of 9 to 12 billion years. We find 970 galaxies with spectroscopic redshifts between 1.4 and 5. This population is 1.6 to 6.2 times larger than previous estimates, with the difference increasing towards brighter magnitudes. Strong ultraviolet continua (in the rest frame of the galaxies) indicate vigorous star formation rates of more than 10-100 solar masses per year. As a consequence, the cosmic star formation rate representing the volume-averaged production of stars is higher than previously measured at redshifts of 3 to 4.

  17. Multi million-to-Billion Atom Molecular Dynamics Simulations of Cavitation-Induced Damage on a Silica Slab

    NASA Astrophysics Data System (ADS)

    Shekhar, Adarsh; Nomura, Ken-Ichi; Kalia, Rajiv; Nakano, Aiichiro; Vashishta, Priya

    2012-02-01

    Cavitation bubble collapse causes severe damage to materials. For example, cavitation erosion is a major threat to the safety of nuclear power plants. The cavitation bubbles may also be utilized for preventing stress corrosion cracking with water jet peening technology. We have performed multi million-to-billion atoms molecular dynamics simulations to investigate the shock-induced cavitation damage mechanism on an amorphous silica slab in water. The system consists of a 60nm thick silica slab immersed in water in an MD box of dimension 285 x 200 x 200 nm3. A nanobubble is created by removing water molecules within a sphere of radius 100 nm. To apply a planar shock, we assign a uniform particle velocity vp on the entire system towards a planar momentum mirror. We have performed the simulation with two kinds of bubbles, an empty bubble and a bubble filled with inert gas. The simulation results reveal nanojet formation during bubble collapse causing damage on the silica surface; however, the damage was significantly reduced in the case of the filled bubble. We will discuss the effect of the presence of inter gas inside the nanobubble on the pressure distribution, the extent of damage, and collapse behavior corresponding the shock front.

  18. Evidence from massive siderite beds for a CO2-rich atmosphere before approximately 1.8 billion years ago

    NASA Technical Reports Server (NTRS)

    Ohmoto, Hiroshi; Watanabe, Yumiko; Kumazawa, Kazumasa

    2004-01-01

    It is generally thought that, in order to compensate for lower solar flux and maintain liquid oceans on the early Earth, methane must have been an important greenhouse gas before approximately 2.2 billion years (Gyr) ago. This is based upon a simple thermodynamic calculation that relates the absence of siderite (FeCO3) in some pre-2.2-Gyr palaeosols to atmospheric CO2 concentrations that would have been too low to have provided the necessary greenhouse effect. Using multi-dimensional thermodynamic analyses and geological evidence, we show here that the absence of siderite in palaeosols does not constrain atmospheric CO2 concentrations. Siderite is absent in many palaeosols (both pre- and post-2.2-Gyr in age) because the O2 concentrations and pH conditions in well-aerated soils have favoured the formation of ferric (Fe3+)-rich minerals, such as goethite, rather than siderite. Siderite, however, has formed throughout geological history in subsurface environments, such as euxinic seas, where anaerobic organisms created H2-rich conditions. The abundance of large, massive siderite-rich beds in pre-1.8-Gyr sedimentary sequences and their carbon isotope ratios indicate that the atmospheric CO2 concentration was more than 100 times greater than today, causing the rain and ocean waters to be more acidic than today. We therefore conclude that CO2 alone (without a significant contribution from methane) could have provided the necessary greenhouse effect to maintain liquid oceans on the early Earth.

  19. Impacts of a 32-billion-gallon bioenergy landscape on land and fossil fuel use in the US

    NASA Astrophysics Data System (ADS)

    Hudiburg, Tara W.; Wang, Weiwei; Khanna, Madhu; Long, Stephen P.; Dwivedi, Puneet; Parton, William J.; Hartman, Melannie; Delucia, Evan H.

    2016-01-01

    Sustainable transportation biofuels may require considerable changes in land use to meet mandated targets. Understanding the possible impact of different policies on land use and greenhouse gas emissions has typically proceeded by exploring either ecosystem or economic modelling. Here we integrate such models to assess the potential for the US Renewable Fuel Standard to reduce greenhouse gas emissions from the transportation sector through the use of cellulosic biofuels. We find that 2022 US emissions are decreased by 7.0 ± 2.5% largely through gasoline displacement and soil carbon storage by perennial grasses. If the Renewable Fuel Standard is accompanied by a cellulosic biofuel tax credit, these emissions could be reduced by 12.3 ± 3.4%. Our integrated approach indicates that transitioning to cellulosic biofuels can meet a 32-billion-gallon Renewable Fuel Standard target with negligible effects on food crop production, while reducing fossil fuel use and greenhouse gas emissions. However, emissions savings are lower than previous estimates that did not account for economic constraints.

  20. From the physics of secondary electron emission to image contrasts in scanning electron microscopy.

    PubMed

    Cazaux, Jacques

    2012-01-01

    Image formation in scanning electron microscopy (SEM) is a combination of physical processes, electron emissions from the sample, and of a technical process related to the detection of a fraction of these electrons. For the present survey of image contrasts in SEM, simplified considerations in the physics of the secondary electron emission yield, δ, are combined with the effects of a partial collection of the emitted secondary electrons. Although some consideration is initially given to the architecture of modern SEM, the main attention is devoted to the material contrasts with the respective roles of the sub-surface and surface compositions of the sample, as well as with the roles of the field effects in the vacuum gap. The recent trends of energy filtering in normal SEM and the reduction of the incident energy to a few electron volts in very low-energy electron microscopy are also considered. For an understanding by the SEM community, the mathematical expressions are explained with simple physical arguments.

  1. Set-up and demonstration of a Low Energy Electron Magnetometer (LEEM)

    NASA Technical Reports Server (NTRS)

    Rayborn, G. H.

    1986-01-01

    Described are the design, construction and test results of a Low Energy Electron Magnetometer (LEEM). The electron source is a commercial electron gun capable of providing several microamperes of electron beam. These electrons, after acceleration through a selected potential difference of 100-300 volts, are sent through two 30 degree second-order focussing parallel plate electrostatic analyzers. The first analyzer acts as a monochromator located in the field-free space. It is capable of providing energy resolution of better than 10 to the -3 power. The second analyzer, located in the test field region, acts as the detector for electrons deflected by the test field. The entire magnetometer system is expected to have a resolution of 1 part in 1000 or better.

  2. Research Frontier

    ERIC Educational Resources Information Center

    Physics Teacher, 1971

    1971-01-01

    New research topics have been brought about by the acceleration of nitrogen nuclei to the energy of 36 billion electron volts. Describes experiments on tumor cells, cosmic rays, and nuclear fission performed with the Bevatron at the Lawrence Berkeley Laboratory. (TS)

  3. Van Allen Probes observations of prompt MeV radiation belt electron acceleration in nonlinear interactions with VLF chorus

    NASA Astrophysics Data System (ADS)

    Foster, J. C.; Erickson, P. J.; Omura, Y.; Baker, D. N.; Kletzing, C. A.; Claudepierre, S. G.

    2017-01-01

    Prompt recovery of MeV (millions of electron Volts) electron populations in the poststorm core of the outer terrestrial radiation belt involves local acceleration of a seed population of energetic electrons in interactions with VLF chorus waves. Electron interactions during the generation of VLF rising tones are strongly nonlinear, such that a fraction of the relativistic electrons at resonant energies are trapped by waves, leading to significant nonadiabatic energy exchange. Through detailed examination of VLF chorus and electron fluxes observed by Van Allen Probes, we investigate the efficiency of nonlinear processes for acceleration of electrons to MeV energies. We find through subpacket analysis of chorus waveforms that electrons with initial energy of hundreds of keV to 3 MeV can be accelerated by 50 keV-200 keV in resonant interactions with a single VLF rising tone on a time scale of 10-100 ms.

  4. The use of electron beams for pasteurization of meats

    SciTech Connect

    Prestwich, K.R.; Kaye, R.J.; Turman, B.N.; Neau, E.L.

    1994-12-01

    Electron beam accelerators can be used for electronic pasteurization of meat products by: (1) using the electrons directly impacting the products, or (2) optimizing the conversion of electron energy to x-rays and treating the product with these x-rays. The choice of process depends on the configuration of the product when it is treated. For electron treatment, ten million electron volt (MeV) kinetic energy is the maximum allowed by international agreement. The depth of penetration of electrons with that energy into a product with density of meat is about five centimeters (cm). Two-sided treatment can be done on products up to 10 cm thick with a two-to-one ratio between minimum and maximum dose. Ground beef patties are about 1.25 cm (0.5 inch thick). Beams with 2.5 MeV electron energy could be used to treat these products. Our calculations show that maximum to minimum dose ratios less than 1.2 can be achieved with this energy if the transverse beam energy is small. If the product thickness is greater than 10 cm, x-rays can provide the needed dose uniformity. Uniform doses can be supplied for pallets with dimensions greater than 1.2 m on each side using x-rays from a 5 MeV electron beam. The efficiency of converting the electron beam to x-rays and configurations to achieve dose uniformity are discussed.

  5. Evaluation testing of a portable vapor detector for Part-Per-Billion (PPB) level UDMH and N2H4

    NASA Technical Reports Server (NTRS)

    Curran, Dan; Lueck, Dale E.

    1995-01-01

    Trace level detection of hydrazine (N2H4), monomethyl hydrazine (MMH) and unsymmetrical dimethylhydrazine (UDMH) has been receiving increased attention over the past several years. In May 1995 the American Conference of Government Industrial Hygienists (ACGIH) lowered their acceptable threshold limit value (TLV) from 100 parts-per-billion (ppb) to 10 ppb. Several types of ppb-level detectors are being developed by the United States Air Force (USAF) Space and Missile Systems Center (SMSC). A breadboard version of a portable, lightweight hydrazine detection sensor was developed and produced by Giner Corp. for the USAF. This sensor was designed for ppb level UDMH and N2H4 vapor detection in near real-time. This instrument employs electrochemical sensing, utilizing a three electrode cell with an anion-exchange polymer electrolyte membrane as the only electrolyte in the system. The sensing, counter and reference electrodes are bonded to the membrane forming a single component. The only liquid required to maintain the sensor is deionized water which hydrates the membrane. At the request of the USAF SMSC, independent testing and evaluation of the breadboard instrument was performed at NASA's Toxic Vapor Detection Laboratory (TVDL) for response to ppb-level N2H4 and UDMH and MMH. The TVDL, located at Kennedy Space Center (KSC) has the unique ability to generate calibrated sample vapor streams of N2H4, UDMH, and MMH over a range from less than 10 ppb to thousands of parts per million (ppm) with full environmental control of relative humidity (0-90%) and temperature (0-50 C). The TVDL routinely performs these types of tests. Referenced sensors were subjected to extensive testing, including precision, linearity, response/recovery times, zero and span drift, humidity and temperature effects as well as ammonia interference. Results of these tests and general operation characteristics are reported.

  6. Air density 2.7 billion years ago limited to less than twice modern levels by fossil raindrop imprints.

    PubMed

    Som, Sanjoy M; Catling, David C; Harnmeijer, Jelte P; Polivka, Peter M; Buick, Roger

    2012-03-28

    According to the 'Faint Young Sun' paradox, during the late Archaean eon a Sun approximately 20% dimmer warmed the early Earth such that it had liquid water and a clement climate. Explanations for this phenomenon have invoked a denser atmosphere that provided warmth by nitrogen pressure broadening or enhanced greenhouse gas concentrations. Such solutions are allowed by geochemical studies and numerical investigations that place approximate concentration limits on Archaean atmospheric gases, including methane, carbon dioxide and oxygen. But no field data constraining ground-level air density and barometric pressure have been reported, leaving the plausibility of these various hypotheses in doubt. Here we show that raindrop imprints in tuffs of the Ventersdorp Supergroup, South Africa, constrain surface air density 2.7 billion years ago to less than twice modern levels. We interpret the raindrop fossils using experiments in which water droplets of known size fall at terminal velocity into fresh and weathered volcanic ash, thus defining a relationship between imprint size and raindrop impact momentum. Fragmentation following raindrop flattening limits raindrop size to a maximum value independent of air density, whereas raindrop terminal velocity varies as the inverse of the square root of air density. If the Archaean raindrops reached the modern maximum measured size, air density must have been less than 2.3 kg m(-3), compared to today's 1.2 kg m(-3), but because such drops rarely occur, air density was more probably below 1.3 kg m(-3). The upper estimate for air density renders the pressure broadening explanation possible, but it is improbable under the likely lower estimates. Our results also disallow the extreme CO(2) levels required for hot Archaean climates.

  7. Validation of an evacuated canister method for measuring part-per-billion levels of chemical warfare agent simulants.

    PubMed

    Coffey, Christopher C; LeBouf, Ryan F; Calvert, Catherine A; Slaven, James E

    2011-08-01

    The National Institute for Occupational Safety and Health (NIOSH) research on direct-reading instruments (DRIs) needed an instantaneous sampling method to provide independent confirmation of the concentrations of chemical warfare agent (CWA) simulants. It was determined that evacuated canisters would be the method of choice. There is no method specifically validated for volatile organic compounds (VOCs) in the NIOSH Manual of Analytical Methods. The purpose of this study was to validate an evacuated canister method for sampling seven specific VOCs that can be used as a simulant for CWA agents (cyclohexane) or influence the DRI measurement of CWA agents (acetone, chloroform, methylene chloride, methyl ethyl ketone, hexane, and carbon tetrachloride [CCl4]). The method used 6-L evacuated stainless-steel fused silica-lined canisters to sample the atmosphere containing VOCs. The contents of the canisters were then introduced into an autosampler/preconcentrator using a microscale purge and trap (MPT) method. The MPT method trapped and concentrated the VOCs in the air sample and removed most of the carbon dioxide and water vapor. After preconcentration, the samples were analyzed using a gas chromatograph with a mass selective detector. The method was tested, evaluated, and validated using the NIOSH recommended guidelines. The evaluation consisted of determining the optimum concentration range for the method; the sample stability over 30 days; and the accuracy, precision, and bias of the method. This method meets the NIOSH guidelines for six of the seven compounds (excluding acetone) tested in the range of 2.3-50 parts per billion (ppb), making it suitable for sampling of these VOCs at the ppb level.

  8. New Schools, Overcrowding Relief, and Achievement Gains in Los Angeles--Strong Returns from a $19.5 Billion Investment. Policy Brief 12-2

    ERIC Educational Resources Information Center

    Welsh, William; Coghlan, Erin; Fuller, Bruce; Dauter, Luke

    2012-01-01

    Aiming to relieve overcrowded schools operating on multiple tracks, the Los Angeles Unified School District (LAUSD) has invested more than $19 billion to build 130 new facilities over the past decade. District leaders asked researchers at Berkeley to estimate the achievement effects of this massive initiative--benefits that may stem from entering…

  9. Runaway electron studies in the ATF torsatron

    SciTech Connect

    England, A.C.; Bell, G.L.; Fowler, R.H.; Glowienka, J.C.; Harris, J.H.; Lee, D.K.; Murakami, M.; Neilson, G.H.; Rasmussen, D.A.; Rome, J.A.; Saltmarsh, M.J.; Wilgen, J.B. )

    1991-07-01

    Runaway electron formation and confinement occur readily in pulsed torsatrons and heliotrons because of the high loop voltages during initiation and termination of the helical and vertical fields ( field ramping'') and the inherently good containment of the electrons on the flux surfaces in the vacuum fields. This has been confirmed for the Advanced Toroidal Facility (AFT) (Fusion Technol. {bold 10}, 179 (1986)) and other stellarators by orbit calculations. Since runaway electrons can cause an unacceptable level of hard x rays near the machine, a runaway electron suppression system was incorporated in ATF. The main component of the system is a movable paddle, which is normally left in the center of the plasma chamber during the field ramps. This device, in conjunction with programmed vertical field ramping, which reduces the volume of good flux surfaces, has proved to be very effective in reducing the runaway electron population. Measurements of hard x rays from ATF have shown that the runaway electrons are produced primarily during the field ramping but that there is usually also a small steady-state runaway electron component during the flat-top'' portion of the fields. The paddle is the main source of the hard x radiation (thick-target bremsstrahlung). There is evidence that some of the runaway electrons may be confined to islands. The maximum x-ray energy found by pulse height analysis is {similar to}12--15 MeV. The mean energy appears to be a few million electron volts. There is a noticeable forward peaking of the bremsstrahlung from the paddle. The limiters do not appear to be major sources of x rays.

  10. Thermodynamic functions of the heated electron subsystem in the field of cold nuclei

    NASA Astrophysics Data System (ADS)

    Sin'ko, G. V.; Smirnov, N. A.; Ovechkin, A. A.; Levashov, P. R.; Khishchenko, K. V.

    2013-06-01

    The paper presents electronic heat capacities and thermal pressures calculated for aluminum and tungsten at densities ρ0 ≤ ρ ≤ 2ρ0 in the case when the temperature of electrons is finite (a few electron-volts) and nuclei are cold. Calculations were done with the all-electron full-potential linear muffin-tin orbital method (FP-LMTO) and compared with data obtained with the Liberman's average-atom model and the Vienna Ab-initio Simulation Package code (VASP) which uses pseudopotentials. It is shown that results obtained with different approaches qualitatively agree within the ranges of electron temperatures and densities under consideration, and quantitatively agree within 10% in most cases.

  11. Biomass as Feedstock for a Bioenergy and Bioproducts Industry: The Technical Feasability of a Billion-Ton Annual Supply

    SciTech Connect

    Perlack, R.D.

    2005-12-15

    land resources of the United States are capable of producing a sustainable supply of biomass sufficient to displace 30 percent or more of the country's present petroleum consumption--the goal set by the Advisory Committee in their vision for biomass technologies. Accomplishing this goal would require approximately 1 billion dry tons of biomass feedstock per year.

  12. Dipolar geomagnetic field and low orbital obliquity during the last two billion years: Evidence from paleomagnetism of evaporite basins

    NASA Astrophysics Data System (ADS)

    Evans, D. A.

    2006-05-01

    Paleomagnetism of climatically sensitive sedimentary rock types, such as glacial deposits and evaporites, can test the uniformitarianism of ancient geomagnetic fields and paleoclimatic zones. Precambrian glacial deposits laid down in near-equatorial paleomagnetic latitudes indicate a paleoclimatic paradox that can be explained either by Snowball Earth episodes, or high orbital obliquity, or dramatically non-uniformitarian geomagnetic fields. Here I present the first global paleomagnetic compilation of the Earth's entire basin-scale evaporite record. Evaporation exceeds precipitation in today's subtropical desert belts, generally within a zone of 15-35° from the equator. Assuming a geocentric axial dipole (GAD) magnetic field for Cenozoic- Mesozoic time, evaporite basins of the past 250 Myr have a volume-weighted mean paleolatitude of 23±4°, also squarely within the subtropics. Carboniferous-Permian evaporites have an indistinguishable weighted-mean paleolatitude of 22±4°, which does not change significantly when recently hypothesized octupolar field components are included in the calculations. Early Paleozoic (including late Ediacaran) evaporites are lower-latitude (weighted mean 10±5°), but detailed analyses of individual examples show this cannot be attributed solely to nondipolar field components or sedimentary inclination biases; the cause may be due to particular paleogeographic effects on regional tropical climates, or incomplete sampling by the paleomagnetic data. Proterozoic (pre-Ediacaran) evaporite basins have a volume- weighted mean inclination of 33±4°, which would correspond to a mean paleolatitude of 18±3° for a pure GAD field. This latter mean is indistinguishable, within error, from the Cenozoic-Mesozoic mean and demonstrates the success of the GAD model as a first-order description of the geomagnetic field for the last two billion years. Also, general circulation climate models of a high-obliquity Earth predict either no strong zonal

  13. Who'll have to pay? The cost of dealing with AIDS in Asia will run into the billions.

    PubMed

    1993-11-03

    In September 1993, at a meeting funded by the Asian Development Bank and the United Nations Development Program, researchers, economists, and government health officials from China, India, Indonesia, South Korea, Burma, the Philippines, Sri Lanka, and Thailand met to discuss the economic effects of human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS) on Asia. The World Health Organization (WHO) places the estimate of the number of people in India who are infected with HIV at around 1 million. However, Jacob John of Vellore Medical College (who first discovered the virus in India) places the estimate at higher than 2.5 million with an increase to 9-18 million by the year 2000. Charles Myers of Harvard University, Mechai Viravaidya of Bangkok's Population and Community Development Association, and Stasia Obremskey ( a health and development consultant) predict 3.4-4.3 million Thais will be infected by that year. According to Obremskey, the number of AIDS cases will reach 650,000, of which 500,000 will die. Health care for full-blown AIDS costs $1016/yr, while lost productivity due to early death costs $22,000 per victim. Myers, Mechai and Obremskey state that Thailand could prevent 3.5 million cases and save $5.1 billion, if people ceased high-risk behavior and the treatment of sexually transmitted diseases was given the highest priority. In the Philippines there are only 416 reported cases of HIV and AIDS, but Dennis Maducduc of the Department of Health AIDS program states that Filipinos are secretive about this, and Orville Solon of the University of the Philippines suggests there are 100 cases for each reported case. Solon believes $15 million has been lost due to infection and death of overseas contract workers who account for 8% of the country's foreign exchange earnings. New studies in Africa, where, as in Thailand, mortality is less than predicted, suggest a less virulent strain of HIV. This apparent fact and prevention, especially

  14. Exploiting the colloidal nanocrystal library to construct electronic devices

    NASA Astrophysics Data System (ADS)

    Choi, Ji-Hyuk; Wang, Han; Oh, Soong Ju; Paik, Taejong; Sung, Pil; Sung, Jinwoo; Ye, Xingchen; Zhao, Tianshuo; Diroll, Benjamin T.; Murray, Christopher B.; Kagan, Cherie R.

    2016-04-01

    Synthetic methods produce libraries of colloidal nanocrystals with tunable physical properties by tailoring the nanocrystal size, shape, and composition. Here, we exploit colloidal nanocrystal diversity and design the materials, interfaces, and processes to construct all-nanocrystal electronic devices using solution-based processes. Metallic silver and semiconducting cadmium selenide nanocrystals are deposited to form high-conductivity and high-mobility thin-film electrodes and channel layers of field-effect transistors. Insulating aluminum oxide nanocrystals are assembled layer by layer with polyelectrolytes to form high-dielectric constant gate insulator layers for low-voltage device operation. Metallic indium nanocrystals are codispersed with silver nanocrystals to integrate an indium supply in the deposited electrodes that serves to passivate and dope the cadmium selenide nanocrystal channel layer. We fabricate all-nanocrystal field-effect transistors on flexible plastics with electron mobilities of 21.7 square centimeters per volt-second.

  15. Transformational silicon electronics.

    PubMed

    Rojas, Jhonathan Prieto; Torres Sevilla, Galo Andres; Ghoneim, Mohamed Tarek; Inayat, Salman Bin; Ahmed, Sally M; Hussain, Aftab Mustansir; Hussain, Muhammad Mustafa

    2014-02-25

    In today's traditional electronics such as in computers or in mobile phones, billions of high-performance, ultra-low-power devices are neatly integrated in extremely compact areas on rigid and brittle but low-cost bulk monocrystalline silicon (100) wafers. Ninety percent of global electronics are made up of silicon. Therefore, we have developed a generic low-cost regenerative batch fabrication process to transform such wafers full of devices into thin (5 μm), mechanically flexible, optically semitransparent silicon fabric with devices, then recycling the remaining wafer to generate multiple silicon fabric with chips and devices, ensuring low-cost and optimal utilization of the whole substrate. We show monocrystalline, amorphous, and polycrystalline silicon and silicon dioxide fabric, all from low-cost bulk silicon (100) wafers with the semiconductor industry's most advanced high-κ/metal gate stack based high-performance, ultra-low-power capacitors, field effect transistors, energy harvesters, and storage to emphasize the effectiveness and versatility of this process to transform traditional electronics into flexible and semitransparent ones for multipurpose applications.

  16. WEDI (Workgroup for Electronic Data Interchange) co-chair predicts big savings from EDI.

    PubMed

    Brophy, J T

    1992-10-01

    Electronic data interchange has the potential to save billions of healthcare dollars--that's the gospel according to Joe Brophy. The Travelers Insurance Company president and co-chair of the Health and Human Services Workgroup on Electronic Data Interchange is taking this sermon to the people.

  17. Mathematical model and software complex for computer simulation of field emission electron sources

    SciTech Connect

    Nikiforov, Konstantin

    2015-03-10

    The software complex developed in MATLAB allows modelling of function of diode and triode structures based on field emission electron sources with complex sub-micron geometry, their volt-ampere characteristics, calculating distribution of electric field for educational and research needs. The goal of this paper is describing the physical-mathematical model, calculation methods and algorithms the software complex is based on, demonstrating the principles of its function and showing results of its work. For getting to know the complex, a demo version with graphical user interface is presented.

  18. Electronic Cigarettes

    MedlinePlus

    ... New FDA Regulations Text Size: A A A Electronic Cigarettes Electronic cigarettes (e-cigarettes) are battery operated products designed ... more about: The latest news and events about electronic cigarettes on this FDA page Electronic cigarette basics ...

  19. a Billion Years of Steady-State Crustal Growth; the 1.9-0.9 GA Evolution of SW Fennoscandia

    NASA Astrophysics Data System (ADS)

    Slagstad, T.; Roberts, N. M.; Andersen, T.; Sauer, S.; Røhr, T. S.

    2012-12-01

    continent-continent collision, but has more recently been placed in the context of orogenesis within an accretionary orogen. Either way, the 1.02-0.98 Ga period was an extensive compressional phase that saw the final accretion and stabilization of all existing fragments of this margin. An extensional phase resumed after 0.96 Ga, and subduction either ceased altogether or jumped outboard again. This billion year period features steady-state crustal growth for much of it. Variations in trench-continent movement (tectonic switching) produce periods of more crustal reworking alternating with periods of greater juvenile addition; alternating compressional and extensional environments stabilize as well as produce arc-derived continental crust. The preserved record, however, is not representative of the crust produced; whereas the dominantly extensional period has produced a large expanse of crust that is partially preserved, a dominantly compressional environment removed crust to the mantle. Although a full continent-continent collision may not have occurred, the regional geodynamics, possibly related to Rodinia formation, have biased the preserved record of crustal growth. Our model supports the concept of steady-state crustal growth, and preservation bias that leaves an episodic record.

  20. Recrystallized Granite Surface Fissures Of The Wasatch Range, Produced Not Later Than 1/4 Billion Years Ago

    NASA Astrophysics Data System (ADS)

    McDonald, Keith L.

    2000-05-01

    Our studies of numerous recrystallized fissures in 4 granite plutons of Wasatch Range, namely, Mount Tuscarora-Wolverine-Millicent,^1,6,7 Bonanza Peak-Midway,^2 Little Cottonwood Canyon and Ferguson Canyon plutons, all of which formed magma chambers reaching Earth-atmosphere interface, establish that they resulted from high thermal gradients rather than passages of earthquake waves. Magma chambers formed, solidified during Permo-Caroniferous Ice Age(roughly, 1/3...1/4 billion yr ago, a time interval preceding period of extrusion of Rocky Mountains, 10^8 yr ago), and while fluid, belched lava flows^5 extending over its reservoir walls to run hundred of meters. We have shown how the magma melts, dilutes and replaces overlying metamorphic rock^7 to reach Earth's surface so that a pluton containing large amounts of dross(Fe-ores, etc.) had a short fluid lifetime. We also described how offshoots from a long-running main fissure form acute angles with that fissure.^3 Such recrystallized fissures, reaching depths of perhaps 100 m, have initial fractures near time of solidification of their uppermost portion of magma chamber while still hot(<= 1600^oF), a time when max. stresses occur near granite surface due to high thermal gradients, owing to snow coverage, cold water contacts due to rain, stream flow over granite surface, partial coverage by ocean, etc., wherever heat sinks might occur, during P-C ice age--when region of Wasatch Range existed at sea level, Salt Lake Valley being covered entirely by ocean water and region east of Wasatch Bouleuard rising gently above Pacific Ocean to elevations of possibly 500-1000 ft, say, at a distance of 10-15 mi to east. This fact is implied by Chinese Wall of white limestone on Grandeur Peak, unequivocally, and similarly another in Neff's Canyon running e. from n. ridge of 9200 ft. saddle-summit, as well as a dozen other ancient calcified stream beds emptying into ocean to w., in Salt Lake Valley. This existed prior to regional

  1. Biomass as Feedstock for a Bioenergy and Bioproducts Industry: The Technical Feasibility of a Billion-Ton Annual Supply, April 2005

    SciTech Connect

    2005-04-01

    The purpose of this report is to determine whether the land resources of the United States are capable of producing a sustainable supply of biomass sufficient to displace 30 percent or more of the country’s present petroleum consumption – the goal set by the Biomass R&D Technical Advisory Committee in their vision for biomass technologies. Accomplishing this goal would require approximately 1 billion dry tons of biomass feedstock per year.

  2. Medical migration. A study projects Americans spending up to $68 billion abroad by 2010 for treatment, but some doubt the trend's momentum.

    PubMed

    Rhea, Shawn

    2008-05-05

    As soaring costs are sending Americans abroad for healthcare, a new study projects they'll spend $68 billion annually by 2010 for overseas treatment. Besides that cost, it could pressure U.S. providers to deliver quality for less. "As you see other cultures where the outcomes look very favorable, then we'll see more people questioning why we can't provide that level of care at similar costs," says Jeffrey Moe, left.

  3. On the possible source of the ionization in the nighttime Martian ionosphere. I - Phobos 2 HARP electron spectrometer measurements

    NASA Technical Reports Server (NTRS)

    Verigin, M. I.; Gringauz, K. I.; Shutte, N. M.; Haider, S. A.; Szego, K.; Kiraly, P.; Nagy, A. F.; Gombosi, T. I.

    1991-01-01

    The measurements of electron spectra in the Martian magnetosphere by the HARP instrument on board the Phobos 2 orbiter are presented. The energy of the electrons (a few tens of electron volts) is sufficient for the impact ionization of the planetary neutral gas, and the characteristic flux of electrons (about 10 exp 8/sq cm per sec) could produce the nightside ionospheric layer with a peak density of a few thousands of electrons per cubic centimeter, which corresponds to densities observed earlier during radio occultations of the Mars 4 and 5 and Viking 1 and 2 spacecraft. The possibility of magnetospheric electron precipitation into the nightside atmosphere of Mars is in agreement with the mainly induced nature of the magnetic field in the planetary magnetotail (as at Venus), while the variability of the Martian nightside ionosphere may be explained by the partial screening of the atmosphere by a weak intrinsic magnetic field of the planet.

  4. Development Fund for Iraq: The Coalition Provisional Authority’s Financial Controls for Electronic Fund Transfer Payments Diminished over Time

    DTIC Science & Technology

    2012-04-30

    York (FRBNY) to make Electronic Fund Transfer ( EFT ) payments for reconstruction activities out of the DFI main account. FRBNY records show that...the Administrator directed about 1,100 EFT payments totaling $5.9 billion in DFI funds from July 2003 through June 2004. EFT payments were made...determine whether the CPA properly accounted for its use of the $5.9 billion in EFT payments made with DFI funds. What SIGIR Recommends This report

  5. Observations of low-energy electrons upstream of the earth's bow shock

    NASA Technical Reports Server (NTRS)

    Reasoner, D. L.

    1974-01-01

    Observations of electron fluxes with a lunar-based electron spectrometer when the moon was upstream of the earth have shown that a subset of observed fluxes are strongly controlled by the interplanetary magnetic field direction. The fluxes occur only when the IMF lines connect back to the earth's bow shock. Observed densities and temperatures were in the ranges 2-4 x 0,001/cu cm and 1.7-2.8 x 1,000,000 K. It is shown that these electrons can account for increases in effective solar wind electron temperatures on bow-shock connected field lines which have been observed previously by other investigators. It is further shown that if a model of the bow shock with an electrostatic potential barrier is assumed, the potential can be estimated to be 500 volts.

  6. Mechanistic insights into energy conservation by flavin-based electron bifurcation.

    PubMed

    Lubner, Carolyn E; Jennings, David P; Mulder, David W; Schut, Gerrit J; Zadvornyy, Oleg A; Hoben, John P; Tokmina-Lukaszewska, Monika; Berry, Luke; Nguyen, Diep M; Lipscomb, Gina L; Bothner, Brian; Jones, Anne K; Miller, Anne-Frances; King, Paul W; Adams, Michael W W; Peters, John W

    2017-04-10

    The recently realized biochemical phenomenon of energy conservation through electron bifurcation provides biology with an elegant means to maximize utilization of metabolic energy. The mechanism of coordinated coupling of exergonic and endergonic oxidation-reduction reactions by a single enzyme complex has been elucidated through optical and paramagnetic spectroscopic studies revealing unprecedented features. Pairs of electrons are bifurcated over more than 1 volt of electrochemical potential by generating a low-potential, highly energetic, unstable flavin semiquinone and directing electron flow to an iron-sulfur cluster with a highly negative potential to overcome the barrier of the endergonic half reaction. The unprecedented range of thermodynamic driving force that is generated by flavin-based electron bifurcation accounts for unique chemical reactions that are catalyzed by these enzymes.

  7. MESSENGER observations of transient bursts of energetic electrons in Mercury's magnetosphere.

    PubMed

    Ho, George C; Krimigis, Stamatios M; Gold, Robert E; Baker, Daniel N; Slavin, James A; Anderson, Brian J; Korth, Haje; Starr, Richard D; Lawrence, David J; McNutt, Ralph L; Solomon, Sean C

    2011-09-30

    The MESSENGER spacecraft began detecting energetic electrons with energies greater than 30 kilo-electron volts (keV) shortly after its insertion into orbit about Mercury. In contrast, no energetic protons were observed. The energetic electrons arrive as bursts lasting from seconds to hours and are most intense close to the planet, distributed in latitude from the equator to the north pole, and present at most local times. Energies can exceed 200 keV but often exhibit cutoffs near 100 keV. Angular distributions of the electrons about the magnetic field suggest that they do not execute complete drift paths around the planet. This set of characteristics demonstrates that Mercury's weak magnetic field does not support Van Allen-type radiation belts, unlike all other planets in the solar system with internal magnetic fields.

  8. Interface control of semiconducting metal oxide layers for efficient and stable inverted polymer solar cells with open-circuit voltages over 1.0 volt.

    PubMed

    Yin, Zhigang; Zheng, Qingdong; Chen, Shan-Ci; Cai, Dongdong

    2013-09-25

    Inverted polymer solar cells (PSCs) with high open-circuit voltages of 1.00-1.06 V are fabricated by using an indenofluorene-containing copolymer (PIFTBT8) as an electron donor material and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) as an electron acceptor material. To improve the photovoltaic performance, interface control of various low-temperature processed ZnO films as cathode buffer layers is systematically investigated for effective electron transportation, while transition metal oxides including MoO3, WO3, NiO, and Cu2O are employed as anode buffer layers for hole-extraction. Incorporation of optimized semiconducting metal oxide interlayers can minimize interfacial power losses, which thus affords large open-circuit voltages (Voc), increased short-circuit current densities (Jsc), and fill factors (FF), eventually contributing to higher power conversion efficiencies (PCEs) as well as better device stability. Due to the improved interfacial contacts and fine-matching energy levels, inverted PSCs with a device configuration of ITO/ZnO/PIFTBT8:PC71BM/MoO3/Ag exhibit a high PCE of 5.05% with a large Voc of 1.04 V, a Jsc of 9.74 mA cm(-2), and an FF of 50.1%. For the single junction inverted PSCs with efficiencies over 5.0%, 1.04 V is the largest Voc ever achieved. By controlling the processing conditions of the active layer, the Voc can further be improved to 1.05 and 1.06 V, with PCEs of 4.70% and 4.18%, respectively. More importantly, the inverted PSCs are ascertained to maintain a PCE of 4.55% (>90% of its initial efficiency) and a Voc of 1.05 V over 180 days, demonstrating good long-term stability, which is much better than that of the conventional devices. The results suggest that the interface engineering of metal oxide interlayers is an important strategy to develop PSCs with good performance.

  9. Accelerating Into the Future: From 0 to GeV in a Few Centimeters (LBNL Summer Lecture Series)

    SciTech Connect

    Leemans, Wim

    2008-07-08

    July 8, 2008 Berkeley Lab lecture: By exciting electric fields in plasma-based waveguides, lasers accelerate electrons in a fraction of the distance conventional accelerators require. The Accelerator and Fusion Research Division's LOASIS program, headed by Wim Leemans, has used 40-trillion-watt laser pulses to deliver billion-electron-volt (1 GeV) electron beams within centimeters. Leemans looks ahead to BELLA, 10-GeV accelerating modules that could power a future linear collider.

  10. Accelerating Into the Future: From 0 to GeV in a Few Centimeters (LBNL Summer Lecture Series)

    SciTech Connect

    Leemans, Wim

    2008-07-08

    Summer Lecture Series 2008: By exciting electric fields in plasma-based waveguides, lasers accelerate electrons in a fraction of the distance conventional accelerators require. The Accelerator and Fusion Research Division's LOASIS program, headed by Wim Leemans, has used 40-trillion-watt laser pulses to deliver billion-electron-volt (1 GeV) electron beams within centimeters. Leemans looks ahead to BELLA, 10-GeV accelerating modules that could power a future linear collider.

  11. Accelerating Into the Future: From 0 to GeV in a Few Centimeters (LBNL Summer Lecture Series)

    ScienceCinema

    Leemans, Wim [LOASIS Program, AFRD

    2016-07-12

    July 8, 2008 Berkeley Lab lecture: By exciting electric fields in plasma-based waveguides, lasers accelerate electrons in a fraction of the distance conventional accelerators require. The Accelerator and Fusion Research Division's LOASIS program, headed by Wim Leemans, has used 40-trillion-watt laser pulses to deliver billion-electron-volt (1 GeV) electron beams within centimeters. Leemans looks ahead to BELLA, 10-GeV accelerating modules that could power a future linear collider.

  12. Accelerating Into the Future: From 0 to GeV in a Few Centimeters (LBNL Summer Lecture Series)

    ScienceCinema

    Leemans, Wim [LOASIS Program, AFRD

    2016-07-12

    Summer Lecture Series 2008: By exciting electric fields in plasma-based waveguides, lasers accelerate electrons in a fraction of the distance conventional accelerators require. The Accelerator and Fusion Research Division's LOASIS program, headed by Wim Leemans, has used 40-trillion-watt laser pulses to deliver billion-electron-volt (1 GeV) electron beams within centimeters. Leemans looks ahead to BELLA, 10-GeV accelerating modules that could power a future linear collider.

  13. Radiative charge transfer in He(+) + H2 collisions in the milli- to nano-electron-volt range: a theoretical study within state-to-state and optical potential approaches.

    PubMed

    Mrugała, Felicja; Kraemer, Wolfgang P

    2013-03-14

    The paper presents a theoretical study of the low-energy dynamics of the radiative charge transfer (RCT) reaction He(+)((2)S)+H2(X(1)Σg (+))→He((1)S)+H2 (+)(X(2)Σg (+))+hν extending our previous studies on radiative association of HeH2 (+) [F. Mrugała, V. Špirko, and W. P. Kraemer, J. Chem. Phys. 118, 10547 (2003); F. Mrugała and W. P. Kraemer, ibid. 122, 224321 (2005)]. The calculations account for the vibrational and rotational motions of the H2/H2 (+) diatomics and for the atom-diatom complex formation in the reactant and the product channels of the RCT reaction. Continuum states of He(+) + H2(v = 0, j = 0) in the collision energy range ~10(-7)-18.6 meV and all quasi-bound states of the He(+) - H2(para; v = 0) complex formed in this range are taken into account. Close-coupling calculations are performed to determine rates of radiative transitions from these states to the continuum and quasi-bound states of the He + H2 (+) system in the energy range extending up to ~0.16 eV above the opening of the HeH(+) + H arrangement channel. From the detailed state-to-state calculated characteristics global functions of the RCT reaction, such as cross-section σ(E), emission intensity I(ν, T), and rate constant k(T) are derived, and are presented together with their counterparts for the radiative association (RA) reaction He(+)((2)S) + H2(X(1)Σg (+))→ HeH2 (+)(X(2)A('))+hν. The rate constant k(RCT) is approximately 20 times larger than k(RA) at the considered temperatures, 0.1 μK-50 K. Formation of rotational Feshbach resonances in the reactant channel plays an important role in both reactions. Transitions mediated by these resonances contribute more than 70% to the respective rates. An extension of the one-dimensional optical potential model is developed to allow inclusion of all three vibrational modes in the atom-diatom system. This three-dimensional optical potential model is used to check to which extent the state-to-state RCT rate constant is influenced by the possibility to access ground state continuum levels well above the opening of the HeH(+)+ H arrangement channel. The results indicate that these transitions contribute about 30% to the "true" rate constant k(RCT) whereas their impact on the populations of the vibration-rotational states of the product H2 (+) ion is only minor. Present theoretical rate constant functions k(RCT)(T) obtained at different approximation levels are compared to experimental data: 1-1.1 × 10(-14) s(-1) cm(3) at T = 15-35 K and ∼7.5 × 10(-15) s(-1) cm(3) at 40 K [M. M. Schauer, S. R. Jefferts, S. E. Barlow, and G. H. Dunn, J. Chem. Phys. 91, 4593 (1989)]. The most reliable theoretical values of k(RCT), obtained by combining results from the state-to-state and the optical potential calculations, are between 2.5 and 3.5 times larger than these experimental numbers. Possible sources for discrepancies are discussed.

  14. Radiative charge transfer in He{sup +}+ H{sub 2} collisions in the milli- to nano-electron-volt range: A theoretical study within state-to-state and optical potential approaches

    SciTech Connect

    Mrugala, Felicja; Kraemer, Wolfgang P.

    2013-03-14

    The paper presents a theoretical study of the low-energy dynamics of the radiative charge transfer (RCT) reaction He{sup +}({sup 2}S)+H{sub 2}(X{sup 1}{Sigma}{sub g}{sup +}){yields}He({sup 1}S)+H{sub 2}{sup +}(X{sup 2}{Sigma}{sub g}{sup +})+h{nu} extending our previous studies on radiative association of HeH{sub 2}{sup +} [F. Mrugala, V. Spirko, and W. P. Kraemer, J. Chem. Phys. 118, 10547 (2003); F. Mrugala and W. P. Kraemer, ibid. 122, 224321 (2005)]. The calculations account for the vibrational and rotational motions of the H{sub 2}/H{sub 2}{sup +} diatomics and for the atom-diatom complex formation in the reactant and the product channels of the RCT reaction. Continuum states of He{sup +}+ H{sub 2}(v= 0, j= 0) in the collision energy range {approx}10{sup -7}-18.6 meV and all quasi-bound states of the He{sup +}- H{sub 2}(para;v= 0) complex formed in this range are taken into account. Close-coupling calculations are performed to determine rates of radiative transitions from these states to the continuum and quasi-bound states of the He +H{sub 2}{sup +} system in the energy range extending up to {approx}0.16 eV above the opening of the HeH{sup +}+ H arrangement channel. From the detailed state-to-state calculated characteristics global functions of the RCT reaction, such as cross-section {sigma}(E), emission intensity I({nu}, T), and rate constant k(T) are derived, and are presented together with their counterparts for the radiative association (RA) reaction He{sup +}({sup 2}S) +H{sub 2}(X{sup 1}{Sigma}{sub g}{sup +}){yields} HeH{sub 2}{sup +}(X{sup 2}A{sup Prime })+h{nu}. The rate constant k{sup RCT} is approximately 20 times larger than k{sup RA} at the considered temperatures, 0.1 {mu}K-50 K. Formation of rotational Feshbach resonances in the reactant channel plays an important role in both reactions. Transitions mediated by these resonances contribute more than 70% to the respective rates. An extension of the one-dimensional optical potential model is developed to allow inclusion of all three vibrational modes in the atom-diatom system. This three-dimensional optical potential model is used to check to which extent the state-to-state RCT rate constant is influenced by the possibility to access ground state continuum levels well above the opening of the HeH{sup +}+ H arrangement channel. The results indicate that these transitions contribute about 30% to the 'true' rate constant k{sup RCT} whereas their impact on the populations of the vibration-rotational states of the product H{sub 2}{sup +} ion is only minor. Present theoretical rate constant functions k{sup RCT}(T) obtained at different approximation levels are compared to experimental data: 1-1.1 Multiplication-Sign 10{sup -14} s{sup -1} cm{sup 3} at T= 15-35 K and {approx}7.5 Multiplication-Sign 10{sup -15} s{sup -1} cm{sup 3} at 40 K [M. M. Schauer, S. R. Jefferts, S. E. Barlow, and G. H. Dunn, J. Chem. Phys. 91, 4593 (1989)]. The most reliable theoretical values of k{sup RCT}, obtained by combining results from the state-to-state and the optical potential calculations, are between 2.5 and 3.5 times larger than these experimental numbers. Possible sources for discrepancies are discussed.

  15. A sub-1-volt analog metal oxide memristive-based synaptic device with large conductance change for energy-efficient spike-based computing systems

    NASA Astrophysics Data System (ADS)

    Hsieh, Cheng-Chih; Roy, Anupam; Chang, Yao-Feng; Shahrjerdi, Davood; Banerjee, Sanjay K.

    2016-11-01

    Nanoscale metal oxide memristors have potential in the development of brain-inspired computing systems that are scalable and efficient. In such systems, memristors represent the native electronic analogues of the biological synapses. In this work, we show cerium oxide based bilayer memristors that are forming-free, low-voltage (˜|0.8 V|), energy-efficient (full on/off switching at ˜8 pJ with 20 ns pulses, intermediate states switching at ˜fJ), and reliable. Furthermore, pulse measurements reveal the analog nature of the memristive device; that is, it can directly be programmed to intermediate resistance states. Leveraging this finding, we demonstrate spike-timing-dependent plasticity, a spike-based Hebbian learning rule. In those experiments, the memristor exhibits a marked change in the normalized synaptic strength (>30 times), when the pre- and post-synaptic neural spikes overlap. This demonstration is an important step towards the physical construction of high density and high connectivity neural networks.

  16. Measurements of the volt-ampere characteristics and the breakdown voltages of direct-current helium and hydrogen discharges in microgaps

    SciTech Connect

    Klas, M.; Matejčik, Š.; Radjenović, B.; Radmilović-Radjenović, M.

    2014-10-15

    The discharge phenomena for micro meter gap sizes include many interesting problems from engineering and physical perspectives. In this paper, the authors deal with the experimental and theoretical results of the breakdown voltage and current-voltage characteristics of the direct-current helium and hydrogen discharges. The measurements were performed at a constant pressure of around one atmosphere, while varying the gap size between two parallel plane tungsten electrodes between 1 μm and 100 μm. From the measured breakdown voltage curves, the effective yields and the ionization coefficients were derived for both gases. Present data for the ionization coefficients correlate with the data obtained for the breakdown voltage curves measured for fixed 100 μm interelectrode separation. The current-voltage characteristics were plotted for the various gap sizes illustrating the role of the field emission effects in the microgaps. Based on the Fowler-Nordheim theory, the enhancement factors were determined. The gap spacing dependence of the field emission current can be explained by the introduction of two ideas, the first being a space charge effect by emitted electrons, and the second a change in the breakdown mechanism. Experimental results, presented here, demonstrate that Townsend phenomenology breaks down when field emission becomes the key mechanism affecting the breakdown and deforming the left hand side of the breakdown voltage curves.

  17. Sensitivity and Noise of Cold-Electron Bolometer Arrays

    NASA Astrophysics Data System (ADS)

    Mukhin, A. S.; Gordeeva, A. V.; Revin, L. S.; Abashin, A. E.; Shishov, A. A.; Pankratov, A. L.; Mahashabde, S.; Kuzmin, L. S.

    2017-01-01

    We perform experimental and theoretical studies of the series-parallel arrays of the cold-electron bolometers integrated into a cross-slot antenna and composed with an immersion silicon lens. This work is aimed at determining the efficiency of radiation absorption by bolometers, their volt-watt sensitivity, and equivalent noise power. The absorbed power was found using two independent methods, which ensured a better reliability of the results. The first method is based on comparing the experimental current-voltage characteristics of bolometers with the model based on the heat-balance equation. The second approach involves simulation of the electromagnetic properties of the system including the antenna, the lens, the bandpass filters, and the radiation source. The discrepancy among the results obtained using various methods does not exceed 30%. Optimization of the experimental setup is proposed to reach the photon-noise detection regime.

  18. Exceptional preservation of aragonite in a circa 3.3 billion year old microbial mat from the Barberton greenstone belt, South Africa

    NASA Astrophysics Data System (ADS)

    Westall, Frances; Cavalazzi, Barbara; Lemelle, Laurence; Marrochhi, Yves; Rouzaud, Jean-Noel; Simionovici, Alexandre; Andreazza, Caroline; Foucher, Frédéric; Thiel, Volker; Hofmann, Axel

    2010-05-01

    Exceptional preservation of aragonite in a circa 3.3 billion year old microbial mat from the Barberton greenstone belt, South Africa Frances Westall, Barbara Cavalazzi, Laurence Lemelle, Yves Marrocchi, Jean-Noël Rouzaud, Alexandre Simionovici, Murielle Salomé, Smail Mostefaoui, Caroline Andreazza, Frédéric Foucher, Jan Toporski, Andrea Jauss, Volker Thiel, Axel Hofmann, Anders Meibom, François Robert Aragonite occurs as a biologically-formed mineral precipitate within modern calcifying microbial mats. It is, however, rarely preserved in the geological record because, as one of the least stable polymorphs of calcium carbonate, it readily converts to calcite in present environmental conditions at the Earth's surface. In an in situ investigation at the micro- to nanometer-scale, we show that 5-10 nm sized nanocrystals of aragonite are preserved within the organic framework of a partially calcified microbial mat from the ~ 3.3 billion year-old Josefsdal Chert in the Barberton greenstone belt, South Africa. Transformation of the aragonite to calcite was blocked by a combination of chemical inhibitors within the crystal lattice, organic molecules coating the nanocrystals and, in particular, to the precocious permeation of the mat by hydrothermal silica. Apart from its exceptional preservation for 3.3 billion years, the identification of aragonite in the Josefsdal microbial mat is the earliest evidence for in situ calcification of a microbial mat. Furthermore, the indications of associated sulphur-reducing bacteria (SRB) activity with calcification strongly support a photosynthetic origin for the mat. This is the most direct evidence for photosynthesis in early Archaean rocks.

  19. Electrons, Electronic Publishing, and Electronic Display.

    ERIC Educational Resources Information Center

    Brownrigg, Edwin B.; Lynch, Clifford A.

    1985-01-01

    Provides a perspective on electronic publishing by distinguishing between "Newtonian" publishing and "quantum-mechanical" publishing. Highlights include media and publishing, works delivered through electronic media, electronic publishing and the printed word, management of intellectual property, and recent copyright-law issues…

  20. Exploring the Relationships between the Electronic Health Record System Components and Patient Outcomes in an Acute Hospital Setting

    ERIC Educational Resources Information Center

    Wiggley, Shirley L.

    2011-01-01

    Purpose: The purpose of this study was to examine the relationship between the electronic health record system components and patient outcomes in an acute hospital setting, given that the current presidential administration has earmarked nearly $50 billion to the implementation of the electronic health record. The relationship between the…

  1. An empirical method for deriving RBE values associated with electrons, photons and radionuclides.

    PubMed

    Bellamy, M; Puskin, J; Hertel, N; Eckerman, K

    2015-12-01

    There is substantial evidence to justify using relative biological effectiveness (RBE) values of >1 for low-energy electrons and photons. But, in the field of radiation protection, radiation associated with low linear energy transfer has been assigned a radiation weighting factor wR of 1. This value may be suitable for radiation protection but, for risk considerations, it is important to evaluate the potential elevated biological effectiveness of radiation to improve the quality of risk estimates. RBE values between 2 and 3 for tritium are implied by several experimental measurements. Additionally, elevated RBE values have been found for other similar low-energy radiation sources. In this work, RBE values are derived for electrons based upon the fractional deposition of absorbed dose of energies less than a few kiloelectron volts. Using this empirical method, RBE values were also derived for monoenergetic photons and 1070 radionuclides from ICRP Publication 107 for which photons and electrons are the primary emissions.

  2. Microbially Induced Sedimentary Structures Recording an Ancient Ecosystem in the ca. 3.48 Billion-Year-Old Dresser Formation, Pilbara, Western Australia

    PubMed Central

    Christian, Daniel; Wacey, David; Hazen, Robert M.

    2013-01-01

    Abstract Microbially induced sedimentary structures (MISS) result from the response of microbial mats to physical sediment dynamics. MISS are cosmopolitan and found in many modern environments, including shelves, tidal flats, lagoons, riverine shores, lakes, interdune areas, and sabkhas. The structures record highly diverse communities of microbial mats and have been reported from numerous intervals in the geological record up to 3.2 billion years (Ga) old. This contribution describes a suite of MISS from some of the oldest well-preserved sedimentary rocks in the geological record, the early Archean (ca. 3.48 Ga) Dresser Formation, Western Australia. Outcrop mapping at the meter to millimeter scale defined five sub-environments characteristic of an ancient coastal sabkha. These sub-environments contain associations of distinct macroscopic and microscopic MISS. Macroscopic MISS include polygonal oscillation cracks and gas domes, erosional remnants and pockets, and mat chips. Microscopic MISS comprise tufts, sinoidal structures, and laminae fabrics; the microscopic laminae are composed of primary carbonaceous matter, pyrite, and hematite, plus trapped and bound grains. Identical suites of MISS occur in equivalent environmental settings through the entire subsequent history of Earth including the present time. This work extends the geological record of MISS by almost 300 million years. Complex mat-forming microbial communities likely existed almost 3.5 billion years ago. Key Words: Archean—Biofilms—Microbial mats—Early Earth—Evolution. Astrobiology 13, 1103–1124. PMID:24205812

  3. Microbially induced sedimentary structures recording an ancient ecosystem in the ca. 3.48 billion-year-old Dresser Formation, Pilbara, Western Australia.

    PubMed

    Noffke, Nora; Christian, Daniel; Wacey, David; Hazen, Robert M

    2013-12-01

    Microbially induced sedimentary structures (MISS) result from the response of microbial mats to physical sediment dynamics. MISS are cosmopolitan and found in many modern environments, including shelves, tidal flats, lagoons, riverine shores, lakes, interdune areas, and sabkhas. The structures record highly diverse communities of microbial mats and have been reported from numerous intervals in the geological record up to 3.2 billion years (Ga) old. This contribution describes a suite of MISS from some of the oldest well-preserved sedimentary rocks in the geological record, the early Archean (ca. 3.48 Ga) Dresser Formation, Western Australia. Outcrop mapping at the meter to millimeter scale defined five sub-environments characteristic of an ancient coastal sabkha. These sub-environments contain associations of distinct macroscopic and microscopic MISS. Macroscopic MISS include polygonal oscillation cracks and gas domes, erosional remnants and pockets, and mat chips. Microscopic MISS comprise tufts, sinoidal structures, and laminae fabrics; the microscopic laminae are composed of primary carbonaceous matter, pyrite, and hematite, plus trapped and bound grains. Identical suites of MISS occur in equivalent environmental settings through the entire subsequent history of Earth including the present time. This work extends the geological record of MISS by almost 300 million years. Complex mat-forming microbial communities likely existed almost 3.5 billion years ago.

  4. An efficient and comprehensive method for drainage network extraction from DEM with billions of pixels using a size-balanced binary search tree

    NASA Astrophysics Data System (ADS)

    Bai, Rui; Li, Tiejian; Huang, Yuefei; Li, Jiaye; Wang, Guangqian

    2015-06-01

    With the increasing resolution of digital elevation models (DEMs), computational efficiency problems have been encountered when extracting the drainage network of a large river basin at billion-pixel scales. The efficiency of the most time-consuming depression-filling pretreatment has been improved by using the O(NlogN) complexity least-cost path search method, but the complete extraction steps following this method have not been proposed and tested. In this paper, an improved O(NlogN) algorithm was proposed by introducing a size-balanced binary search tree (BST) to improve the efficiency of the depression-filling pretreatment further. The following extraction steps, including the flow direction determination and the upslope area accumulation, were also redesigned to benefit from this improvement. Therefore, an efficient and comprehensive method was developed. The method was tested to extract drainage networks of 31 river basins with areas greater than 500,000 km2 from the 30-m-resolution ASTER GDEM and two sub-basins with areas of approximately 1000 km2 from the 1-m-resolution airborne LiDAR DEM. Complete drainage networks with both vector features and topographic parameters were obtained with time consumptions in O(NlogN) complexity. The results indicate that the developed method can be used to extract entire drainage networks from DEMs with billions of pixels with high efficiency.

  5. Technical challenges, past and future, in implementing THERESA: a one million patient, one billion item computer-based patient record and decision support system

    NASA Astrophysics Data System (ADS)

    Camp, Henry N.

    1996-02-01

    Challenges in implementing a computer-based patient record (CPR)--such as absolute data integrity, high availability, permanent on-line storage of very large complex records, rapid search times, ease of use, commercial viability, and portability to other hospitals and doctor's offices--are given along with their significance, the solutions, and their successes. The THERESA CPR has been used sine 1983 in direct patient care by a public hospital that is the primary care provider to 350,000 people. It has 1000 beds with 45,000 admissions and 750,000 outpatient visits annually. The system supports direct provider entry, including by physicians, of complete medical `documents'. Its demonstration site currently contains 1.1 billion data items on 1 million patients. It is also a clinical decision-aiding tool used for quality assurance and cost containment, for teaching as faculty and students can easily find and `thumb through' all cases similar to a particular study, and for research with over a billion medical items that can be searched and analyzed on-line within context and with continuity. The same software can also run in a desktop microcomputer managing a private practice physician's office.

  6. For states that opt out of Medicaid expansion: 3.6 million fewer insured and $8.4 billion less in federal payments.

    PubMed

    Price, Carter C; Eibner, Christine

    2013-06-01

    The US Supreme Court's ruling on the Affordable Care Act in 2012 allowed states to opt out of the health reform law's Medicaid expansion. Since that ruling, fourteen governors have announced that their states will not expand their Medicaid programs. We used the RAND COMPARE microsimulation to analyze how opting out of Medicaid expansion would affect coverage and spending, and whether alternative policy options-such as partial expansion of Medicaid-could cover as many people at lower costs to states. With fourteen states opting out, we estimate that 3.6 million fewer people would be insured, federal transfer payments to those states could fall by $8.4 billion, and state spending on uncompensated care could increase by $1 billion in 2016, compared to what would be expected if all states participated in the expansion. These effects were only partially mitigated by alternative options we considered. We conclude that in terms of coverage, cost, and federal payments, states would do best to expand Medicaid.

  7. A Portable Electronic Nose For Hydrazine and Monomethyl Hydrazine Detection

    NASA Technical Reports Server (NTRS)

    Young, Rebecca C.; Linnell, Bruce R.; Peterson, Barbara V.; Brooks, Kathy B.; Griffin, Tim P.

    2004-01-01

    The Space Program and military use large quantities Hydrazine (Hz) and monomethyl hydrazine (MMI-I) as rocket propellant. These substances are very toxic and are suspected human carcinogens. The American Conference of Governmental Industrial Hygienist set the threshold limit value to be 10 parts per billion (ppb). Current off-the-shelf portable instruments require 10 to 20 minutes of exposure to detect 10 ppb concentration. This shortcofriing is not acceptable for many operations. A new prototype instrument using a gas sensor array and pattern recognition software technology (i.e., an electronic nose) has demonstrated the ability to identify either Hz or MM}{ and quantify their concentrations at 10 parts per billion in 90 seconds. This paper describes the design of the portable electronic nose (e-nose) instrument, test equipment setup, test protocol, pattern recognition algorithm, concentration estimation method, and laboratory test results.

  8. Federal Research: Super Collider Estimates and Germany’s Industrially Produced Magnets

    DTIC Science & Technology

    1991-02-12

    DESY Deutsches Elektronen-Synchrotron DOE Department of Energy GeV billion electron volts HEPAP High Energy Physics Advisory Panel HERA Hadron Electron...Advisory Panel ( HEPAP ) report indicated that reducing the energy would risk losing important physics. The panel fully endorsed the design as well as the...the Laboratory’s work. Two DOE reviews were completed by OER and ICE staff. At DOE’s request, the third independent review was conducted by the HEPAP

  9. Defence electronics industry profile, 1990-1991

    NASA Astrophysics Data System (ADS)

    The defense electronics industry profiled in this review comprises an estimated 150 Canadian companies that develop, manufacture, and repair radio and communications equipment, radars for surveillance and navigation, air traffic control systems, acoustic and infrared sensors, computers for navigation and fire control, signal processors and display units, special-purpose electronic components, and systems engineering and associated software. Canadian defense electronics companies generally serve market niches and end users of their products are limited to the military, government agencies, or commercial airlines. Geographically, the industry is concentrated in Ontario and Quebec, where about 91 percent of the industry's production and employment is found. In 1989, the estimated revenue of the industry was $2.36 billion, and exports totalled an estimated $1.4 billion. Strengths and weaknesses of the industry are discussed in terms of such factors as the relatively small size of Canadian companies, the ability of Canadian firms to access research and development opportunities and export markets in the United States, the dependence on foreign-made components, and international competition.

  10. Electrons in the ionospheric source cone - Evidence for runaway electrons as carriers of downward Birkeland currents

    NASA Technical Reports Server (NTRS)

    Klumpar, D. M.; Heikkila, W. J.

    1982-01-01

    Extremely intense field-aligned fluxes of low energy electrons have been observed with ISIS-2 streaming out of the ionosphere at auroral latitudes. Fluxes in excess of 10 billion per sq cm sec ster at energies below 500 eV with peak fluxes from 10 to 100 eV were detected at 1400 km. The electrons are very strongly field-aligned, having pitch angles confined within 10 deg of the magnetic field. Since they are so intense and so highly collimated they cannot be produced by atmospheric backscattering of a primary auroral beam. These electrons are sometimes associated with ionospheric ions that have been accelerated transverse to the magnetic field. They occur in regions of downward field-aligned current, and may thus be carriers of the current, thus far unidentified. It is suggested that they are runaway electrons from the ionosphere produced by a downward field-aligned component of the electric field.

  11. REVIEWS OF TOPICAL PROBLEMS: Solid-surface electron spectroscopy

    NASA Astrophysics Data System (ADS)

    Gomoyunova, M. V.

    1982-01-01

    Electron spectroscopy (ES) of the surface of a solid comprises a set of methods of studying its elemental composition, structure, electronic structure, and dynamics. The essence of almost all the methods consists in obtaining and studying the energy spectra and angular distributions of electrons emitted by the surface of the solid upon irradiation with fluxes of photons, electrons, or ions, or upon creating a strong electric field near it. Depending on the nature of the probe, one can distinguish photoelectron, secondary-electron, ion-electron, and field spectroscopy. Each of them is realized by several methods. In practically all the methods analysis of the characteristics that are obtained consists of singling out certain unitypical elementary events of interaction of the probe agent with the surface layers of the solid. As a rule, the depth of probing is determined by the mean free path of the electron with respect to inelastic interaction. In the electron energy range from tens to approximately hundreds of electron volts in various materials, it constitutes from one to several atomic layers. In determining elemental composition, the sensitivity of most of the ES methods is approximately equal to hundredths of a monolayer. One can employ a scanning probe to obtain the distribution of the elements over the surface of the specimen. Most of the ES methods have been invented in the past decade. At present the studies in the field of surface physics are intensively developing and have great scientific and important applied significance. This review briefly treats the physical fundamentals of the ES methods, their potentialities, classifies the methods, gives examples to illustrate them, and cursorily throws light on the fundamental technical means of realizing the methods.

  12. Growth of consumer-directed health plans to one-half of all employer-sponsored insurance could save $57 billion annually.

    PubMed

    Haviland, Amelia M; Marquis, M Susan; McDevitt, Roland D; Sood, Neeraj

    2012-05-01

    Enrollment is increasing in consumer-directed health insurance plans, which feature high deductibles and a personal health care savings account. We project that an increase in market share of these plans--from the current level of 13 percent of employer-sponsored insurance to 50 percent--could reduce annual health care spending by about $57 billion. That decrease would be the equivalent of a 4 percent decline in total health care spending for the nonelderly. However, such growth in consumer-directed plan enrollment also has the potential to reduce the use of recommended health care services, as well as to increase premiums for traditional health insurance plans, as healthier individuals drop traditional coverage and enroll in consumer-directed plans. In this article we explore options that policy makers and employers facing these challenges should consider, including more refined plan designs and decision support systems to promote recommended services.

  13. Six climate change-related events in the United States accounted for about $14 billion in lost lives and health costs.

    PubMed

    Knowlton, Kim; Rotkin-Ellman, Miriam; Geballe, Linda; Max, Wendy; Solomon, Gina M

    2011-11-01

    The future health costs associated with predicted climate change-related events such as hurricanes, heat waves, and floods are projected to be enormous. This article estimates the health costs associated with six climate change-related events that struck the United States between 2000 and 2009. The six case studies came from categories of climate change-related events projected to worsen with continued global warming-ozone pollution, heat waves, hurricanes, infectious disease outbreaks, river flooding, and wildfires. We estimate that the health costs exceeded $14 billion, with 95 percent due to the value of lives lost prematurely. Actual health care costs were an estimated $740 million. This reflects more than 760,000 encounters with the health care system. Our analysis provides scientists and policy makers with a methodology to use in estimating future health costs related to climate change and highlights the growing need for public health preparedness.

  14. Utilizing artificial neural networks in MATLAB to achieve parts-per-billion mass measurement accuracy with a fourier transform ion cyclotron resonance mass spectrometer.

    PubMed

    Williams, D Keith; Kovach, Alexander L; Muddiman, David C; Hanck, Kenneth W

    2009-07-01

    Fourier transform ion cyclotron resonance mass spectrometry has the ability to realize exceptional mass measurement accuracy (MMA); MMA is one of the most significant attributes of mass spectrometric measurements as it affords extraordinary molecular specificity. However, due to space-charge effects, the achievable MMA significantly depends on the total number of ions trapped in the ICR cell for a particular measurement, as well as relative ion abundance of a given species. Artificial neural network calibration in conjunction with automatic gain control (AGC) is utilized in these experiments to formally account for the differences in total ion population in the ICR cell between the external calibration spectra and experimental spectra. In addition, artificial neural network calibration is used to account for both differences in total ion population in the ICR cell as well as relative ion abundance of a given species, which also affords mean MMA values at the parts-per-billion level.

  15. Electronics Curriculum.

    ERIC Educational Resources Information Center

    Prickett, Charlotte

    This document presents results of research conducted by industry representatives regarding tasks performed by electronic technicians and line manufacturing electro-mechanical technicians in Arizona electronics industries. Based on this research, a competency-based curriculum was developed for training entry-level electronics technicians. Twelve…

  16. Electronic Prescribing

    MedlinePlus

    ... Do you prescribe electronically?” For more information about electronic prescribing, call 1-800-MEDICARE (1-800-633- ... TTY users should call 1-877-486-2048 . Electronic eRx Prescribing I went to the pharmacy, and ...

  17. A sub-1-volt nanoelectromechanical switching device.

    PubMed

    Lee, Jeong Oen; Song, Yong-Ha; Kim, Min-Wu; Kang, Min-Ho; Oh, Jae-Sub; Yang, Hyun-Ho; Yoon, Jun-Bo

    2013-01-01

    Nanoelectromechanical (NEM) switches have received widespread attention as promising candidates in the drive to surmount the physical limitations currently faced by complementary metal oxide semiconductor technology. The NEM switch has demonstrated superior characteristics including quasi-zero leakage behaviour, excellent density capability and operation in harsh environments. However, an unacceptably high operating voltage (4-20 V) has posed a major obstacle in the practical use of the NEM switch in low-power integrated circuits. To utilize the NEM switch widely as a core device component in ultralow power applications, the operation voltage needs to be reduced to 1 V or below. However, sub-1 V actuation has not yet been demonstrated because of fabrication difficulties and irreversible switching failure caused by surface adhesion. Here, we report the sub-1 V operation of a NEM switch through the introduction of a novel pipe clip device structure and an effective air gap fabrication technique. This achievement is primarily attributed to the incorporation of a 4-nm-thick air gap, which is the smallest reported so far for a NEM switch generated using a 'top-down' approach. Our structure and process can potentially be utilized in various nanogap-related applications, including NEM switch-based ultralow-power integrated circuits, NEM resonators, nanogap electrodes for scientific research and sensors.

  18. The Breakthrough Behind the Chevy Volt Battery

    DOE R&D Accomplishments Database

    Lerner, Louise

    2011-03-28

    A revolutionary breakthrough cathode for lithium-ion batteries—the kind in your cell phone, laptop and new hybrid cars—makes them last longer, run more safely and perform better than batteries currently on the market.

  19. Improvement of depth resolution and detection efficiency by control of secondary-electrons in single-event three-dimensional time-of-flight Rutherford backscattering spectrometry

    NASA Astrophysics Data System (ADS)

    Abo, Satoshi; Hamada, Yasuhisa; Seidl, Albert; Wakaya, Fujio; Takai, Mikio

    2015-04-01

    An improvement of a depth resolution and a detection efficiency in single-event three-dimensional time-of-flight (TOF) Rutherford backscattering spectrometry (RBS) is discussed on both simulation and experiment by control of secondary electron trajectories using sample bias voltage. The secondary electron, used for a start signal in single-event TOF-RBS, flies more directly to a secondary electron detector with the positive sample bias voltage of several tens of volt than that without sample bias voltage in the simulation. The simulated collection efficiency of the secondary electrons also increases with the positive sample bias voltage of several tens of volt. These simulation results indicate the possibility of a smaller depth resolution and a shorter measurement time in single-event TOF-RBS with positive sample bias voltage. The measurement time for the Pt-stripe sample using single-event three-dimensional TOF-RBS with the sample bias voltage of +100 V is 65% shorter than that without sample bias voltage, resulting in a less sample damage by a probe beam. The depth resolution for the Pt stripes under the 50-nm-thick SiO2 cover-layer with the sample bias voltage of +100 V is 4 nm smaller than that without sample bias voltage. Positive sample bias voltage improves the depth resolution and the detection efficiency in single-event three-dimensional TOF-RBS without an influence on the beam focusing.

  20. Millions and Billions of Channels

    NASA Astrophysics Data System (ADS)

    Leigh, Darren; Horowitz, Paul

    The history of the Harvard SETI group is inextricably linked with the history of Paul Horowitz. Horowitz became enamored with SETI as a student at Harvard, reading Ed Purcell's paper "Radio Astronomy and Communication Through Space" (Purcell, 1960), discussing with his roommates a class that Carl Sagan was teaching there using a draft of Shklovskii and Sagan's "Intelligent Life in the Universe" (Shklovskii and Sagan, 1966) as a text, and finally attending a Loeb Lecture series at Harvard by Frank Drake (Drake, 1969). The series was officially about pulsars but Drake did manage to slip in one inspiring talk about SETI. Horowitz says that "It was this lecture that launched me into this field; it was a revelation that you could go beyond idle speculation - you could actually calculate stuff."

  1. Coupled-Sturmian and perturbative treatments of electron transfer and ionization in high-energy p -He sup + collisions

    SciTech Connect

    Winter, T.G. Department of Physics, Rice University, Houston, Texas 77251 ); Alston, S.G. )

    1992-02-01

    Cross sections have been determined for electron transfer and ionization in collisions between protons and He{sup +} ions at proton energies from several hundred kilo-electron-volts to 2 MeV. A coupled-Sturmian approach is taken, extending the work of Winter (Phys. Rev. A 35, 3799 (1987)) and Stodden {ital et} {ital al}. (Phys. Rev. A 41, 1281 (1990)) to high energies where perturbative approaches are expected to be valid. An explicit connection is made with the first-order Born approximation for ionization and the impulse version of the distorted, strong-potential Born approximation for electron transfer. The capture cross section is shown to be affected by the presence of target basis functions of positive energy near {ital v}{sup 2}/2, corresponding to the Thomas mechanism.

  2. Electronic Photography

    NASA Technical Reports Server (NTRS)

    Payne, Meredith Lindsay

    1995-01-01

    The main objective was to assist in the production of electronic images in the Electronic Photography Lab (EPL). The EPL is a new facility serving the electronic photographic needs of the Langley community. The purpose of the Electronic Photography lab is to provide Langley with access to digital imaging technology. Although the EPL has been in operation for less than one year, almost 1,000 images have been produced. The decision to establish the lab was made after careful determination of the centers needs for electronic photography. The LaRC community requires electronic photography for the production of electronic printing, Web sites, desktop publications, and its increased enhancement capabilities. In addition to general use, other considerations went into the planning of the EPL. For example, electronic photography is much less of a burden on the environment compared to conventional photography. Also, the possibilities of an on-line database and retrieval system could make locating past work more efficient. Finally, information in an electronic image is quantified, making measurements and calculations easier for the researcher.

  3. Electron Bifurcation

    SciTech Connect

    Peters, John W.; Miller, Anne-Frances; Jones, Anne K.; King, Paul W.; Adams, Michael W. W.

    2016-04-01

    Electron bifurcation is the recently recognized third mechanism of biological energy conservation. It simultaneously couples exergonic and endergonic oxidation-reduction reactions to circumvent thermodynamic barriers and minimize free energy loss. Little is known about the details of how electron bifurcating enzymes function, but specifics are beginning to emerge for several bifurcating enzymes. To date, those characterized contain a collection of redox cofactors including flavins and iron-sulfur clusters. Here we discuss the current understanding of bifurcating enzymes and the mechanistic features required to reversibly partition multiple electrons from a single redox site into exergonic and endergonic electron transfer paths.

  4. Microfluidic electronics.

    PubMed

    Cheng, Shi; Wu, Zhigang

    2012-08-21

    Microfluidics, a field that has been well-established for several decades, has seen extensive applications in the areas of biology, chemistry, and medicine. However, it might be very hard to imagine how such soft microfluidic devices would be used in other areas, such as electronics, in which stiff, solid metals, insulators, and semiconductors have previously dominated. Very recently, things have radically changed. Taking advantage of native properties of microfluidics, advances in microfluidics-based electronics have shown great potential in numerous new appealing applications, e.g. bio-inspired devices, body-worn healthcare and medical sensing systems, and ergonomic units, in which conventional rigid, bulky electronics are facing insurmountable obstacles to fulfil the demand on comfortable user experience. Not only would the birth of microfluidic electronics contribute to both the microfluidics and electronics fields, but it may also shape the future of our daily life. Nevertheless, microfluidic electronics are still at a very early stage, and significant efforts in research and development are needed to advance this emerging field. The intention of this article is to review recent research outcomes in the field of microfluidic electronics, and address current technical challenges and issues. The outlook of future development in microfluidic electronic devices and systems, as well as new fabrication techniques, is also discussed. Moreover, the authors would like to inspire both the microfluidics and electronics communities to further exploit this newly-established field.

  5. Paper electronics.

    PubMed

    Tobjörk, Daniel; Österbacka, Ronald

    2011-05-03

    Paper is ubiquitous in everyday life and a truly low-cost substrate. The use of paper substrates could be extended even further, if electronic applications would be applied next to or below the printed graphics. However, applying electronics on paper is challenging. The paper surface is not only very rough compared to plastics, but is also porous. While this is detrimental for most electronic devices manufactured directly onto paper substrates, there are also approaches that are compatible with the rough and absorptive paper surface. In this review, recent advances and possibilities of these approaches are evaluated and the limitations of paper electronics are discussed.

  6. Wave acceleration of electrons in the Van Allen radiation belts.

    PubMed

    Horne, Richard B; Thorne, Richard M; Shprits, Yuri Y; Meredith, Nigel P; Glauert, Sarah A; Smith, Andy J; Kanekal, Shrikanth G; Baker, Daniel N; Engebretson, Mark J; Posch, Jennifer L; Spasojevic, Maria; Inan, Umran S; Pickett, Jolene S; Decreau, Pierrette M E

    2005-09-08

    The Van Allen radiation belts are two regions encircling the Earth in which energetic charged particles are trapped inside the Earth's magnetic field. Their properties vary according to solar activity and they represent a hazard to satellites and humans in space. An important challenge has been to explain how the charged particles within these belts are accelerated to very high energies of several million electron volts. Here we show, on the basis of the analysis of a rare event where the outer radiation belt was depleted and then re-formed closer to the Earth, that the long established theory of acceleration by radial diffusion is inadequate; the electrons are accelerated more effectively by electromagnetic waves at frequencies of a few kilohertz. Wave acceleration can increase the electron flux by more than three orders of magnitude over the observed timescale of one to two days, more than sufficient to explain the new radiation belt. Wave acceleration could also be important for Jupiter, Saturn and other astrophysical objects with magnetic fields.

  7. Superthermal electrons at Mars: Photoelectrons, solar wind electrons, and dust storm influences

    NASA Astrophysics Data System (ADS)

    Xu, Shaosui

    Mars is unique in the solar system in terms of its interaction with solar wind because it lacks of a significant intrinsic global magnetic field but possesses localized strong crustal fields. This interaction results in a very complex magnetic topology at Mars so that superthermal electrons, mainly including photoelectrons and solar wind electrons, can be distinctively important for such a complicated planetary space environment. These energetic electrons (1-1000 electron volts) can carry and rapidly redistribute energy along the magnetic field lines. They are also a reliable tool to deduce the Martian magnetic topology, which is critical to understand the electromagnetic dynamics of the Martian space environment. The investigation methodology involves both data analysis and modeling. This dissertation mainly investigates three topics of superthermal electrons at Mars. (1) This dissertation confirms that the long-lived influence of Martian low-altitude dust storms on high-altitude photoelectron fluxes is common for a wide range of energy and pitch angles and determines that this effect originates from the thermosphere-ionosphere source region of the photoelectrons, rather than at exospheric altitudes at or above MGS. Through simulations, the results suggest that the global dust storm altered the photoelectron fluxes by causing CO2 to be the dominant species at a much larger altitude range than usual. (2) Because the integral of the production rate above the superthermal electron exobase is about the same for all solar zenith angles, quite counterintuitively, it is found, observationally and numerically/theoretically, that the high-altitude photoelectron fluxes are quite independent of solar zenith angle. (3) Based on the energy spectral (flux against energy) difference between photoelectrons and solar wind electrons, a statistical approach is taken to distinguish the two populations and also allows us to quantify the occurrence rate of solar wind electron

  8. Communications Electronics.

    ERIC Educational Resources Information Center

    Vorderstrasse, Ron; Siebert, Leo

    This module is the third in a series of electronics publications and serves as a supplement to "General Electronics Technician." It is designed to provide students with an overview of the broad field of communications. Included are those tasks above the basic skills level that allow students to progress to a higher level of competency in the…

  9. Printed Electronics

    NASA Technical Reports Server (NTRS)

    Crain, John M. (Inventor); Lettow, John S. (Inventor); Aksay, Ilhan A. (Inventor); Korkut, Sibel (Inventor); Chiang, Katherine S. (Inventor); Chen, Chuan-Hua (Inventor); Prud'Homme, Robert K. (Inventor)

    2015-01-01

    Printed electronic device comprising a substrate onto at least one surface of which has been applied a layer of an electrically conductive ink comprising functionalized graphene sheets and at least one binder. A method of preparing printed electronic devices is further disclosed.

  10. Printed Electronics

    NASA Technical Reports Server (NTRS)

    Crain, John M. (Inventor); Lettow, John S. (Inventor); Aksay, Ilhan A. (Inventor); Korkut, Sibel A. (Inventor); Chiang, Katherine S. (Inventor); Chen, Chuan-Hua (Inventor); Prud'Homme, Robert K. (Inventor)

    2014-01-01

    Printed electronic device comprising a substrate onto at least one surface of which has been applied a layer of an electrically conductive ink comprising functionalized graphene sheets and at least one binder. A method of preparing printed electronic devices is further disclosed.

  11. Printed electronics

    NASA Technical Reports Server (NTRS)

    Crain, John M. (Inventor); Lettow, John S. (Inventor); Aksay, Ilhan A. (Inventor); Korkut, Sibel A. (Inventor); Chiang, Katherine S. (Inventor); Chen, Chuan-hua (Inventor); Prud'Homme, Robert K. (Inventor)

    2012-01-01

    Printed electronic device comprising a substrate onto at least one surface of which has been applied a layer of an electrically conductive ink comprising functionalized graphene sheets and at least one binder. A method of preparing printed electronic devices is further disclosed.

  12. Printed Electronics

    NASA Technical Reports Server (NTRS)

    Crain, John M. (Inventor); Lettow, John S. (Inventor); Aksay, Ilhan A. (Inventor); Korkut, Sibel (Inventor); Chiang, Katherine S. (Inventor); Chen, Chuan-Hua (Inventor); Prud'Homme, Robert K. (Inventor)

    2016-01-01

    Printed electronic device comprising a substrate onto at least one surface of which has been applied a layer of an electrically conductive ink comprising functionalized graphene sheets and at least one binder. A method of preparing printed electronic devices is further disclosed.

  13. Electronic Cereal.

    ERIC Educational Resources Information Center

    Frentrup, Julie R.; Phillips, Donald B.

    1996-01-01

    Describes activities that use Froot Loops breakfast cereal to help students master the concepts of valence electrons and chemical bonding and the implications of the duet and octet rules. Involves students working in groups to create electron dot structures for various compounds. (JRH)

  14. Electron Beam Technology for Environmental Pollution Control.

    PubMed

    Chmielewski, Andrzej G; Han, Bumsoo

    2016-10-01

    Worldwide, there are over 1700 electron beam (EB) units in commercial use, providing an estimated added value to numerous products, amounting to 100 billion USD or more. High-current electron accelerators are used in diverse industries to enhance the physical and chemical properties of materials and to reduce undesirable contaminants such as pathogens, toxic byproducts, or emissions. Over the past few decades, EB technologies have been developed aimed at ensuring the safety of gaseous and liquid effluents discharged to the environment. It has been demonstrated that EB technologies for flue gas treatment (SO x and NO x removal), wastewater purification, and sludge hygienization can be effectively deployed to mitigate environmental degradation. Recently, extensive work has been carried out on the use of EB for environmental remediation, which also includes the removal of emerging contaminants such as VOCs, endocrine disrupting chemicals (EDCs), and potential EDCs.

  15. Integrated electronic platforms for weight loss

    PubMed Central

    McCrady-Spitzer, Shelly K; Levine, James A

    2010-01-01

    What can be done to build effective weight loss solutions for the 1.5 billion people with obesity? It is self-evident that no one good solution exists for people who are overweight or obese, otherwise it would have been applied across the people who need it worldwide. There is, therefore, an urgent need for approaches that will afford weight loss; what is more, such approaches need to be scalable. For that reason, it is attractive to consider electronic platforms as an avenue for scalable weight loss solutions. Such platforms often do not require substantial investments but rather the integration of pre-existing off-the-shelf components. In this article we explore the concepts and design challenges for electronic platforms that precipitate weight loss. PMID:20214426

  16. Safely Managed Sanitation for All Means Fecal Sludge Management for At Least 1.8 Billion People in Low and Middle Income Countries.

    PubMed

    Berendes, David M; Sumner, Trent A; Brown, Joe M

    2017-02-14

    Although global access to sanitation is increasing, safe management of fecal waste is a rapidly growing challenge in low- and middle-income countries (LMICs). The goal of this study was to evaluate the current need for fecal sludge management (FSM) in LMICs by region, urban/rural status, and wealth. Recent Demographic and Health Survey data from 58 countries (847 685 surveys) were used to classify households by sanitation facility (facilities needing FSM, sewered facilities, ecological sanitation/other, or no facilities). Onsite piped water infrastructure was quantified to approximate need for wastewater management and downstream treatment. Over all surveyed nations, 63% of households used facilities requiring FSM, totaling approximately 1.8 billion people. Rural areas had similar proportions of toilets requiring FSM as urban areas. FSM needs scaled inversely with wealth: in the poorest quintile, households' sanitation facilities were almost 170 times more likely to require FSM (vs sewerage) than in the richest quintile. About one out of five households needing FSM had onsite piped water infrastructure, indicating domestic or reticulated wastewater infrastructure may be required if lacking for safe management of aqueous waste streams. FSM strategies must be included in future sanitation investment to achieve safe management of fecal wastes and protect public health.

  17. Two-phase increase in the maximum size of life over 3.5 billion years reflects biological innovation and environmental opportunity

    PubMed Central

    Payne, Jonathan L.; Boyer, Alison G.; Brown, James H.; Finnegan, Seth; Kowalewski, Michał; Krause, Richard A.; Lyons, S. Kathleen; McClain, Craig R.; McShea, Daniel W.; Novack-Gottshall, Philip M.; Smith, Felisa A.; Stempien, Jennifer A.; Wang, Steve C.

    2009-01-01

    The maximum size of organisms has increased enormously since the initial appearance of life >3.5 billion years ago (Gya), but the pattern and timing of this size increase is poorly known. Consequently, controls underlying the size spectrum of the global biota have been difficult to evaluate. Our period-level compilation of the largest known fossil organisms demonstrates that maximum size increased by 16 orders of magnitude since life first appeared in the fossil record. The great majority of the increase is accounted for by 2 discrete steps of approximately equal magnitude: the first in the middle of the Paleoproterozoic Era (≈1.9 Gya) and the second during the late Neoproterozoic and early Paleozoic eras (0.6–0.45 Gya). Each size step required a major innovation in organismal complexity—first the eukaryotic cell and later eukaryotic multicellularity. These size steps coincide with, or slightly postdate, increases in the concentration of atmospheric oxygen, suggesting latent evolutionary potential was realized soon after environmental limitations were removed. PMID:19106296

  18. From the Cover: Sulfur isotopes of organic matter preserved in 3.45-billion-year-old stromatolites reveal microbial metabolism

    NASA Astrophysics Data System (ADS)

    Bontognali, Tomaso R. R.; Sessions, Alex L.; Allwood, Abigail C.; Fischer, Woodward W.; Grotzinger, John P.; Summons, Roger E.; Eiler, John M.

    2012-09-01

    The 3.45-billion-year-old Strelley Pool Formation of Western Australia preserves stromatolites that are considered among the oldest evidence for life on Earth. In places of exceptional preservation, these stromatolites contain laminae rich in organic carbon, interpreted as the fossil remains of ancient microbial mats. To better understand the biogeochemistry of these rocks, we performed microscale in situ sulfur isotope measurements of the preserved organic sulfur, including both Δ33S and . This approach allows us to tie physiological inference from isotope ratios directly to fossil biomass, providing a means to understand sulfur metabolism that is complimentary to, and independent from, inorganic proxies (e.g., pyrite). Δ33S values of the kerogen reveal mass-anomalous fractionations expected of the Archean sulfur cycle, whereas values show large fractionations at very small spatial scales, including values below -15‰. We interpret these isotopic patterns as recording the process of sulfurization of organic matter by H2S in heterogeneous mat pore-waters influenced by respiratory S metabolism. Positive Δ33S anomalies suggest that disproportionation of elemental sulfur would have been a prominent microbial process in these communities.

  19. Performance as Promised: How the Chandra X-ray Observatory Accomplished One of Nasa's Most Challenging Missions for Billions of Dollars Less than Originally Planned

    NASA Technical Reports Server (NTRS)

    Davidson, Greg; Hefner, Keith

    2004-01-01

    As the nation looks toward bold new ventures in space, the Chandra X-ray Observatory program offers an example of how billion-dollar missions can be successfully developed within tightening fiscal constraints. Chandra experienced many of challenges facing bold space programs (state-of-the-art technical requirements and budget-induced slips and restructurings), and yet the Chandra team achieved nearly all the originally envisioned performance for dramatically lower cost. This was accomplished by a combination of team- work, systems engineering, advanced technology insertion, and effective approaches for program implementation. A thorough tradeoff of science utility vs. cost led to the selection of a highly elliptical orbit with uncrewed robotic delivery, deployment, and maintenance. Progressive, focused technology demonstrations were accomplished prior to commitment of major resources to critical elements of the system design, such as the high resolution mirror assembly (HRMA). Pathfinder hardware was developed to reduce risks. A variety of schedule risk reduction measures were implemented and resulted in the X-ray calibration taking place exactly within five days of its originally planned date after after five years of development. The team worked together in an effective manner to contain requirements creep. reductions such as the ACIS-2 chip device. It is estimated that the above combination of measures achieved the avoidance of over $4B in costs, while enabling a highly successful mission.

  20. Multiresidue method for N-methyl carbamates and metabolite pesticide residues at the parts-per-billion level in selected representative commodities of fruit and vegetable crop groups.

    PubMed

    Podhorniak, Lynda V; Schenck, Frank J; Krynitsky, Alexander; Griffith, Francis

    2004-01-01

    A reversed-phase liquid chromatographic method with both fluorescence and mass spectrometric detection is presented for the determination of 13 parent N-methyl carbamate pesticides and their metabolites, as well as piperonyl butoxide, for a total of 24 compounds in selected fruits and vegetables. The commodities chosen were of special concern to the U.S. Environmental Protection Agency (EPA) because they had the least amount of monitoring data for dietary exposure estimates used in risk assessment. The method is based on a judicious selection of procedures from U.S. Food and Drug Administration sources such as the Pesticide Analytical Manual (Volume I), and Laboratory Information Bulletins, plus additional material from the chemical literature combined in a manner to recover the N-methyl carbamates and their metabolites at the 1 microg/kg or 1 part-per-billion level. The method uses an acetone extraction, followed by an aminopropyl solid-phase extraction cleanup. Determination of residues is by RP-LC, in which the liquid chromatograph is interfaced with either a fluorescence or a mass spectrometric detector. The method is designed so that a set of 6 samples can be prepared in 1 working day for overnight instrumental analysis. Recovery data are presented from analyses of selected commodities in some of EPA's fruit and vegetable crop groupings. A table listing relative retention times is presented for the N-methyl carbamates and their metabolites.

  1. An efficient probe for rapid detection of cyanide in water at parts per billion levels and naked-eye detection of endogenous cyanide.

    PubMed

    Kumari, Namita; Jha, Satadru; Bhattacharya, Santanu

    2014-03-01

    A new molecular probe based on an oxidized bis-indolyl skeleton has been developed for rapid and sensitive visual detection of cyanide ions in water and also for the detection of endogenously bound cyanide. The probe allows the "naked-eye" detection of cyanide ions in water with a visual color change from red to yellow (Δλmax =80 nm) with the immediate addition of the probe. It shows high selectivity towards the cyanide ion without any interference from other anions. The detection of cyanide by the probe is ratiometric, thus making the detection quantitative. A Michael-type addition reaction of the probe with the cyanide ion takes place during this chemodosimetric process. In water, the detection limit was found to be at the parts per million level, which improved drastically when a neutral micellar medium was employed, and it showed a parts-per-billion-level detection, which is even 25-fold lower than the permitted limits of cyanide in water. The probe could also efficiently detect the endogenously bound cyanide in cassava (a staple food) with a clear visual color change without requiring any sample pretreatment and/or any special reaction conditions such as pH or temperature. Thus the probe could serve as a practical naked-eye probe for "in-field" experiments without requiring any sophisticated instruments.

  2. Electronic neuroprocessors

    NASA Technical Reports Server (NTRS)

    Thakoor, Anil

    1991-01-01

    The JPL Center for Space Microelectronics Technology (CSMT) is actively pursuing research in the neural network theory, algorithms, and electronics as well as optoelectronic neural net hardware implementations, to explore the strengths and application potential for a variety of NASA, DoD, as well as commercial application problems, where conventional computing techniques are extremely time-consuming, cumbersome, or simply non-existent. An overview of the JPL electronic neural network hardware development activities and some of the striking applications of the JPL electronic neuroprocessors are presented.

  3. Electronic plants

    PubMed Central

    Stavrinidou, Eleni; Gabrielsson, Roger; Gomez, Eliot; Crispin, Xavier; Nilsson, Ove; Simon, Daniel T.; Berggren, Magnus

    2015-01-01

    The roots, stems, leaves, and vascular circuitry of higher plants are responsible for conveying the chemical signals that regulate growth and functions. From a certain perspective, these features are analogous to the contacts, interconnections, devices, and wires of discrete and integrated electronic circuits. Although many attempts have been made to augment plant function with electroactive materials, plants’ “circuitry” has never been directly merged with electronics. We report analog and digital organic electronic circuits and devices manufactured in living plants. The four key components of a circuit have been achieved using the xylem, leaves, veins, and signals of the plant as the template and integral part of the circuit elements and functions. With integrated and distributed electronics in plants, one can envisage a range of applications including precision recording and regulation of physiology, energy harvesting from photosynthesis, and alternatives to genetic modification for plant optimization. PMID:26702448

  4. Discovery of a 12 billion solar mass black hole at redshift 6.3 and its challenge to the black hole/galaxy co-evolution at cosmic dawn

    NASA Astrophysics Data System (ADS)

    Wu, Xue-Bing; Wang, Feige; Fan, Xiaohui; Yi, Weimin; Zuo, Wenwen; Bian, Fuyan; Jiang, Linhua; McGreer, Ian; Wang, Ran; Yang, Jinyi; Yang, Qian; Thompson, David; Beletsky, Yuri

    2015-08-01

    To date about 40 quasars with redshifts z>6 have been discovered. Each quasar harbors a black hole with a mass of about one billion solar masses. The existence of such black holes when the Universe was less than one billion years after the Big Bang presents significant challenges to theories of the formation and growth of black holes and the black hole/galaxy co-evolution. I will report a recent discovery of an ultra-luminous quasar at redshift z=6.30, which has an observed optical and near-infrared luminosity a few times greater than those of previously known z>6 quasars. With near-infrared spectroscopy, we obtain a black hole mass of about 12 billion solar masses, which is well consistent with the mass derived by assuming an Eddington-limited accretion. This ultra-luminous quasar with a 12 billion solar mass black hole at z>6 provides a unique laboratory to the study of the mass assembly and galaxy formation around the most massive black holes in the early Universe. It raises further challenges to the black hole/galaxy co-evolution in the epoch of cosmic reionization because the black hole needs to grow much faster than the host galaxy.

  5. Follow the money: How the billions of dollars that flow from smokers in poor nations to companies in rich nations greatly exceed funding for global tobacco control and what might be done about it

    PubMed Central

    2010-01-01

    The business of selling cigarettes is increasingly concentrated in the hands of five tobacco companies that collectively control almost 90% of the world's cigarette market, four of which are publicly traded corporations. The economic activities of these cigarette manufacturers can be monitored through their reports to shareholders and other public documents. Reports for 2008 show that the revenues of these five companies exceeded $300 billion, of which more than $160 billion was provided to governments as taxes, and that corporate earnings of the four publicly traded companies were over $25 billion, of which $14 billion was retained after corporate income taxes were paid. By contrast, funding for domestic and international tobacco control is not reliably reported. Estimated funding for global tobacco control in 2008, at $240 million, is significantly lower than resources provided to address other high-mortality global health challenges. Tobacco control has not yet benefited from the innovative finance mechanisms that are in place for HIV/AIDS, tuberculosis and malaria. The Framework Convention On Tobacco Control (FCTC) process could be used to redirect some of the earnings from transnational tobacco sales to fund FCTC implementation or other global health efforts. PMID:20610436

  6. Educational Assistance Overpayments, A Billion Dollar Problem--A Look at the Causes, Solutions, and Collection Efforts. Veterans Administration. Report to the Congress by the Comptroller General of the United States.

    ERIC Educational Resources Information Center

    Comptroller General of the U.S., Washington, DC.

    Overpayments to veterans and veterans' dependents under the VA's educational assistance programs have increased dramatically in recent years; as of the end of 1975, cumulative overpayments totaled almost $1.4 billion. In fiscal year 1967, overpayments represented 0.7 percent of VA's total educational benefits paid, whereas in the first six months…

  7. Follow the money: how the billions of dollars that flow from smokers in poor nations to companies in rich nations greatly exceed funding for global tobacco control and what might be done about it.

    PubMed

    Callard, Cynthia

    2010-08-01

    The business of selling cigarettes is increasingly concentrated in the hands of five tobacco companies that collectively control almost 90% of the world's cigarette market, four of which are publicly traded corporations. The economic activities of these cigarette manufacturers can be monitored through their reports to shareholders and other public documents. Reports for 2008 show that the revenues of these five companies exceeded $300 billion, of which more than $160 billion was provided to governments as taxes, and that corporate earnings of the four publicly traded companies were over $25 billion, of which $14 billion was retained after corporate income taxes were paid. By contrast, funding for domestic and international tobacco control is not reliably reported. Estimated funding for global tobacco control in 2008, at $240 million, is significantly lower than resources provided to address other highmortality global health challenges. Tobacco control has not yet benefited from the innovative finance mechanisms that are in place for HIV/AIDS, tuberculosis and malaria. The Framework Convention On Tobacco Control (FCTC) process could be used to redirect some of the earnings from transnational tobacco sales to fund FCTC implementation or other global health efforts.

  8. Electron-emission yield of Al, Cu, and Au for the impact of swift bare light ions

    SciTech Connect

    Benka, O.; Schinner, A.; Fink, T.; Pfaffenlehner, M.

    1995-11-01

    The electron emission yield induced by mega-electron-volt H{sup +}, He{sup 2+}, Li{sup 3+}, B{sup 5+}, and C{sup 6+} impact on aluminum, copper, and gold targets was measured. We found a significant deviation of the results from a simple proportionality to the stopping power, especially for heavier ions and low projectile velocities. Using a slightly modified model by J. E. Borovsky and D. M. Suszcynsky [Phys. Rev. A {bold 43}, 1433 (1991)] our experiments could be well represented. In this model the collective electric field generated along the projectile`s path was taken into account. Consequently, the positive ion channel appears to be the dominant mechanism that leads beyond a projectile-independent yield--to--stopping power ratio.

  9. Microwave measurements of energy lost to longitudinal modes by single electron bunches traversing periodic structures

    SciTech Connect

    Wang, J.W.; Loew, G.A.; Weaver, J.N.; Wilson, P.B.

    1981-10-01

    In the design of future linear colliders, it will be important to minimize the loss of beam energy due to the excitation of higher-order modes in the accelerator structure by single bunches of electrons or positrons. This loss is not only detrimental in itself but also gives rise to energy spectrum widening and transverse emittance growth. Microwave measurements made on disk-loaded and alternating-spoke structures to determine the loss to the longitudinal modes are described. In these measurements the Gaussian bunch is simulated by a current pulse of the same shape transmitted through the structure on an axial center conductor. Results to date are presented for the total longitudinal loss parameter per period K in volts per picocoulomb.

  10. Ab-initio study of structural, electronic, and transport properties of zigzag GaP nanotubes.

    PubMed

    Srivastava, Anurag; Jain, Sumit Kumar; Khare, Purnima Swarup

    2014-03-01

    Stability and electronic properties of zigzag (3 ≤ n ≤ 16) gallium phosphide nanotubes (GaP NTs) have been analyzed by employing a systematic ab-intio approach based on density functional theory using generalized gradient approximation with revised Perdew Burke Ernzerhoff type parameterization. Diameter dependence of bond length, buckling, binding energy, and band gap has been investigated and the analysis shows that the bond length and buckling decreases with increasing diameter of the tube, highest binding energy of (16, 0) confirms this as the most stable amongst all the NTs taken into consideration. The present GaP NTs shows direct band gap and it increases with diameter of the tubes. Using a two probe model for (4, 0) NT the I-V relationship shows an exponential increase in current on applying bias voltage beyond 1.73 volt.

  11. Design of power electronics for TVC EMA systems

    NASA Technical Reports Server (NTRS)

    Nelms, R. Mark

    1993-01-01

    The Composite Development Division of the Propulsion Laboratory at Marshall Space Flight Center (MSFC) is currently developing a class of electromechanical actuators (EMA's) for use in space transportation applications such as thrust vector control (TVC) and propellant control valves (PCV). These high power servomechanisms will require rugged, reliable, and compact power electronic modules capable of modulating several hundred amperes of current at up to 270 volts. MSFC has selected the brushless dc motor for implementation in EMA's. This report presents the results of an investigation into the applicability of two new technologies, MOS-controlled thyristors (MCT's) and pulse density modulation (PDM), to the control of brushless dc motors in EMA systems. MCT's are new power semiconductor devices, which combine the high voltage and current capabilities of conventional thyristors and the low gate drive requirements of metal oxide semiconductor field effect transistors (MOSFET's). The commanded signals in a PDM system are synthesized using a series of sinusoidal pulses instead of a series of square pulses as in a pulse width modulation (PWM) system. A resonant dc link inverter is employed to generate the sinusoidal pulses in the PDM system. This inverter permits zero-voltage switching of all semiconductors which reduces switching losses and switching stresses. The objectives of this project are to develop and validate an analytical model of the MCT device when used in high power motor control applications and to design, fabricate, and test a prototype electronic circuit employing both MCT and PDM technology for controlling a brushless dc motor.

  12. Design of power electronics for TVC EMA systems

    NASA Astrophysics Data System (ADS)

    Nelms, R. Mark

    1993-08-01

    The Composite Development Division of the Propulsion Laboratory at Marshall Space Flight Center (MSFC) is currently developing a class of electromechanical actuators (EMA's) for use in space transportation applications such as thrust vector control (TVC) and propellant control valves (PCV). These high power servomechanisms will require rugged, reliable, and compact power electronic modules capable of modulating several hundred amperes of current at up to 270 volts. MSFC has selected the brushless dc motor for implementation in EMA's. This report presents the results of an investigation into the applicability of two new technologies, MOS-controlled thyristors (MCT's) and pulse density modulation (PDM), to the control of brushless dc motors in EMA systems. MCT's are new power semiconductor devices, which combine the high voltage and current capabilities of conventional thyristors and the low gate drive requirements of metal oxide semiconductor field effect transistors (MOSFET's). The commanded signals in a PDM system are synthesized using a series of sinusoidal pulses instead of a series of square pulses as in a pulse width modulation (PWM) system. A resonant dc link inverter is employed to generate the sinusoidal pulses in the PDM system. This inverter permits zero-voltage switching of all semiconductors which reduces switching losses and switching stresses. The objectives of this project are to develop and validate an analytical model of the MCT device when used in high power motor control applications and to design, fabricate, and test a prototype electronic circuit employing both MCT and PDM technology for controlling a brushless dc motor.

  13. Electron tube

    DOEpatents

    Suyama, Motohiro [Hamamatsu, JP; Fukasawa, Atsuhito [Hamamatsu, JP; Arisaka, Katsushi [Los Angeles, CA; Wang, Hanguo [North Hills, CA

    2011-12-20

    An electron tube of the present invention includes: a vacuum vessel including a face plate portion made of synthetic silica and having a surface on which a photoelectric surface is provided, a stem portion arranged facing the photoelectric surface and made of synthetic silica, and a side tube portion having one end connected to the face plate portion and the other end connected to the stem portion and made of synthetic silica; a projection portion arranged in the vacuum vessel, extending from the stem portion toward the photoelectric surface, and made of synthetic silica; and an electron detector arranged on the projection portion, for detecting electrons from the photoelectric surface, and made of silicon.

  14. ELECTRONIC SYSTEM

    DOEpatents

    Robison, G.H. et al.

    1960-11-15

    An electronic system is described for indicating the occurrence of a plurality of electrically detectable events within predetermined time intervals. It is comprised of separate input means electrically associated with the events under observation: an electronic channel associated with each input means including control means and indicating means; timing means associated with each of the input means and the control means and adapted to derive a signal from the input means and apply it after a predetermined time to the control means to effect deactivation of each of the channels; and means for resetting the system to its initial condition after observation of each group of events.

  15. Electron Impedances

    SciTech Connect

    P Cameron

    2011-12-31

    It is only recently, and particularly with the quantum Hall effect and the development of nanoelectronics, that impedances on the scale of molecules, atoms and single electrons have gained attention. In what follows the possibility that characteristic impedances might be defined for the photon and the single free electron is explored is some detail, the premise being that the concepts of electrical and mechanical impedances are relevant to the elementary particle. The scale invariant quantum Hall impedance is pivotal in this exploration, as is the two body problem and Mach's principle.

  16. Electronic system

    DOEpatents

    Robison, G H; Dickson, J F

    1960-11-15

    An electronic system is designed for indicating the occurrence of a plurality of electrically detectable events within predetermined time intervals. The system comprises separate input means electrically associated with the events under observation an electronic channel associated with each input means, including control means and indicating means; timing means adapted to apply a signal from the input means after a predetermined time to the control means to deactivate each of the channels; and means for resetting the system to its initial condition after the observation of each group of events. (D.L.C.)

  17. Stable Isotope Geochemistry of Extremely Well-Preserved 2.45-Billion-Year-Old Hydrothermal Systems in the Vetreny Belt, Baltic Shield: Insights into Paleohydrosphere

    NASA Astrophysics Data System (ADS)

    Zakharov, D. O.; Bindeman, I. N.

    2015-12-01

    The early Paleoproterozoic was an eventful period in the Earth's history. The first portions of free oxygen emerged in the atmosphere, Snowball Earth glaciations happened several times and the first supercontinent broke up due to extensive rifting. These events should have affected the stable isotopic composition of the hydrosphere. In this study, we use rocks that were altered in underwater hydrothermal systems to investigate the stable isotopic composition of the hydrosphere 2.39-2.45 billion years ago (hereinafter, Ga). Extremely low-δ18O (down to -27.5‰ SMOW) rocks from 2.39 Ga metamorphosed subglacial hydrothermal systems of the Belomorian belt, Baltic Shield formed at near-equatorial latitudes suggesting a Snowball (or Slushball) Earth glaciation. These results motivated us to look at temporally and geographically close hydrothermal systems from the unmetamorhposed 2.45 Ga Vetreny Belt rift. The length of the rift is 250 km and it is composed of high-Mg basalts, mafic-ultramafic intrusions and sedimentary successions. We examined several localities of high-Mg basalt flows that include astonishingly fresh pillow lavas, often with preserved volcanic glass, eruptive breccias, and hydrothermal alteration zones. Collected samples serve a great textural evidence of water-rock interaction that occurred in situ while basalts were cooling. The preliminary results from coexisting quartz and epidote (T, D18O=311°C), and from coexisting calcite and quartz (T, D18O=190°C) yield values of δ18O of involved water between -1.6 and -0.9 ‰. The values of δ13C in calcites vary between -4.0 and -2.3 ‰. It is likely that hydrothermal fluids operated in the Vetreny Belt rift were derived from seawater that is no different from modern oceanic water in terms of δ18O. Apparently, the rift was a Paleoproterozoic analog of the modern Red Sea, filled with oceanic water. The result is important because the Vetreny Belt rift predates the onset of Snowball Earth glaciation at 2

  18. Composition and syngeneity of molecular fossils from the 2.78 to 2.45 billion-year-old Mount Bruce Supergroup, Pilbara Craton, Western Australia

    NASA Astrophysics Data System (ADS)

    Brocks, Jochen J.; Buick, Roger; Logan, Graham A.; Summons, Roger E.

    2003-11-01

    Shales of very low metamorphic grade from the 2.78 to 2.45 billion-year-old (Ga) Mount Bruce Supergroup, Pilbara Craton, Western Australia, were analyzed for solvent extractable hydrocarbons. Samples were collected from ten drill cores and two mines in a sampling area centered in the Hamersley Basin near Wittenoom and ranging 200 km to the southeast, 100 km to the southwest and 70 km to the northwest. Almost all analyzed kerogenous sedimentary rocks yielded solvent extractable organic matter. Concentrations of total saturated hydrocarbons were commonly in the range of 1 to 20 ppm (μg/g rock) but reached maximum values of 1000 ppm. The abundance of aromatic hydrocarbons was ˜1 to 30 ppm. Analysis of the extracts by gas chromatography-mass spectrometry (GC-MS) and GC-MS metastable reaction monitoring (MRM) revealed the presence of n-alkanes, mid- and end-branched monomethylalkanes, ω-cyclohexylalkanes, acyclic isoprenoids, diamondoids, tri- to pentacyclic terpanes, steranes, aromatic steroids and polyaromatic hydrocarbons. Neither plant biomarkers nor hydrocarbon distributions indicative of Phanerozoic contamination were detected. The host kerogens of the hydrocarbons were depleted in 13C by 2 to 21‰ relative to n-alkanes, a pattern typical of, although more extreme than, other Precambrian samples. Acyclic isoprenoids showed carbon isotopic depletion relative to n-alkanes and concentrations of 2α-methylhopanes were relatively high, features rarely observed in the Phanerozoic but characteristic of many other Precambrian bitumens. Molecular parameters, including sterane and hopane ratios at their apparent thermal maxima, condensate-like alkane profiles, high mono- and triaromatic steroid maturity parameters, high methyladamantane and methyldiamantane indices and high methylphenanthrene maturity ratios, indicate thermal maturities in the wet-gas generation zone. Additionally, extracts from shales associated with iron ore deposits at Tom Price and Newman have

  19. Interaction, at Ambient Temperature and 80 °C, between Minerals and Artificial Seawaters Resembling the Present Ocean Composition and that of 4.0 Billion Years Ago

    NASA Astrophysics Data System (ADS)

    Carneiro, Cristine E. A.; Stabile, Antonio C.; Gomes, Frederico P.; da Costa, Antonio C. S.; Zaia, Cássia T. B. V.; Zaia, Dimas A. M.

    2016-10-01

    Probably one of the most important roles played by minerals in the origin of life on Earth was to pre-concentrate biomolecules from the prebiotic seas. There are other ways to pre concentrate biomolecules such as wetting/drying cycles and freezing/sublimation. However, adsorption is most important. If the pre-concentration did not occur—because of degradation of the minerals—other roles played by them such as protection against degradation, formation of polymers, or even as primitive cell walls would be seriously compromised. We studied the interaction of two artificial seawaters with kaolinite, bentonite, montmorillonite, goethite, ferrihydrite and quartz. One seawater has a major cation and anion composition similar to that of the oceans of the Earth 4.0 billion years ago (ASW 4.0 Ga). In the other, the major cations and anions are an average of the compositions of the seawaters of today (ASWT). When ASWT, which is rich in Na+ and Cl-, interacted with bentonite and montmorrilonite structural collapse occurred on the 001 plane. However, ASW 4.0 Ga, which is rich in Mg2+ and SO4 2-, did not induce this behavior. When ASW 4.0 Ga was reacted with the minerals for 24 h at room temperature and 80 °C, the release of Si and Al to the fluid was below 1 % of the amount in the minerals—meaning that dissolution of the minerals did not occur. In general, minerals adsorbed Mg2+ and K+ from the ASW 4.0 Ga and these cations could be used for the formation of polymers. Also, when the minerals were mixed with ASW 4.0 Ga at 80 °C and ASWT at room temperature or 80 °C it caused the precipitation of CaSO4•2H2O and halite, respectively. Finally, further experiments (adsorption, formation of polymers, protection of molecules against degradation, primitive cell wall formation) performed under the conditions described in this paper will probably be more representative of what happened on the prebiotic Earth.

  20. Basic Electronics.

    ERIC Educational Resources Information Center

    Hartman, Lonnie; Huston, Jane, Ed.

    The skills taught in these materials for a seven-unit course were those identified as necessary not only for entry-level electronic technicians but for those in other occupations as well, including appliance repair, heating and air conditioning, and auto mechanics. The seven units are on shop orientation and safety principles, introduction to…

  1. Electronic tongue

    NASA Technical Reports Server (NTRS)

    Kuhlman, Kimberly (Inventor); Buehler, Martin G. (Inventor)

    2004-01-01

    An ion selective electrode (ISE) array is described, as well as methods for producing the same. The array can contain multiple ISE which are individually electronically addressed. The addressing allows simplified preparation of the array. The array can be used for water quality monitoring, for example.

  2. Electronic Money.

    ERIC Educational Resources Information Center

    Schilling, Tim

    Thirty years ago a cashless society was predicted for the near future; paper currency and checks would be an antiquated symbol of the past. Consumers would embrace a new alternative for making payments: electronic money. But currency is still used for 87% of payments, mainly for "nickel and dime" purchases. And checks are the payment…

  3. Electron Cooling

    NASA Astrophysics Data System (ADS)

    Ellison, Timothy J. P.

    1991-08-01

    Electron cooling is a method of reducing the 6 -dimensional phase space volume of a stored ion beam. The technique was invented by Budker and first developed by him and his colleagues at the Institute for Nuclear Physics in Novosibirsk. Further studies of electron cooling were subsequently performed at CERN and Fermilab. At the Indiana University Cyclotron Facility (IUCF) an electron cooling system was designed, built, and commissioned in 1988. This was the highest energy system built to date (270 keV for cooling 500 MeV protons) and the first such system to be used as an instrument for performing nuclear and atomic physics experiments. This dissertation summarizes the design principles; measurements of the longitudinal drag rate (cooling force), equilibrium cooled beam properties and effective longitudinal electron beam temperature. These measurements are compared with theory and with the measured performance of other cooling systems. In addition the feasibility of extending this technology to energies an order of magnitude higher are discussed.

  4. Electronics Technician.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. Center on Education and Training for Employment.

    This document contains 27 units to consider for use in a tech prep competency profile for the occupation of electronics technician. All the units listed will not necessarily apply to every situation or tech prep consortium, nor will all the competencies within each unit be appropriate. Several units appear within each specific occupation and would…

  5. Electronic Portfolios.

    ERIC Educational Resources Information Center

    Purves, Alan C.

    1996-01-01

    Outlines three forms of electronic portfolio based on a student's work, a class project about a specific topic, and a class seminar on a broad topic. Discusses logistical problems of management, access, and cross-referencing; technical problems of input, access, and copying; and theoretical issues of the lack of realia, of ownership and copyright,…

  6. Nanodosimetry of Auger electrons: A case study from the decay of 125I and 0-18-eV electron stopping cross sections of cytosine

    NASA Astrophysics Data System (ADS)

    Michaud, M.; Bazin, M.; Sanche, L.

    2013-03-01

    Radiopharmaceuticals emitting Auger electrons are often injected into patients undergoing cancer treatment with targeted radionuclide therapy (TRT). In this type of radiotherapy, the radiation source is radial and most of the emitted primary particles are low-energy electrons (LEEs) having kinetic energies distributed mostly from zero to a few hundred electron volts with very short ranges in biological media. These LEEs generate a high density of energy deposits and clustered damage, thus offering a relative biological effectiveness comparable to that of alpha particles. In this paper, we present a simple model and corresponding measurements to assess the energy deposited near the site of the radiopharmaceuticals in TRT. As an example, a calculation is performed for the decay of a single 125I radionuclide surrounded by a 1-nm-radius spherical shell of cytosine molecules using the energy spectrum of LEEs emitted by 125I along with their stopping cross sections between 0 and 18 eV. The dose absorbed by the cytosine shell, which occupies a volume of 4 nm3, is extremely high. It amounts to 79 kGy per decay of which 3%, 39%, and 58% is attributed to vibrational excitations, electronic excitations, and ionization processes, respectively.

  7. Relativistic ultrafast electron diffraction from molecules in the gas phase (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Yang, Jie; Guehr, Markus; Vecchione, Theodore; Robinson, Matthew S.; Li, Renkai; Hartmann, Nick; Shen, Xiaozhe; Centurion, Martin; Wang, Xijie

    2016-10-01

    Ultrafast electron diffraction (UED) is a powerful technique that can be used to resolve structural changes of gas molecules during a photochemical reaction. However, the temporal resolution in pump-probe experiments has been limited to the few-ps level by the space-charge effect that broadens the electron pulse duration and by velocity mismatch between the pump laser pulses and the probe electron pulses, making only long-lived intermediate states accessible. Taking advantage of relativistic effects, Mega-electron-volt (MeV) electrons can be used to suppress both the space-charge effect and the velocity mismatch, and hence to achieve a temporal resolution that is fast enough to follow coherent nuclear motion in the target molecules. In this presentation, we show the first MeV UED experiments on gas phase targets. These experiments not only demonstrate that femtosecond temporal resolution is achieved, but also show that the spatial resolution is not compromised. This unprecedented combination of spatiotemporal resolution is sufficient to image coherent nuclear motions, and opens the door to a new class of experiments where the structural changes can be followed simultaneously in both space and time.

  8. Free Energy and Temperature Dependence of Electron Transfer at the Metal-Electrolyte Interface

    NASA Astrophysics Data System (ADS)

    Chidsey, Christopher E. D.

    1991-02-01

    The rate constant of the electron-transfer reaction between a gold electrode and an electroactive ferrocene group has been measured at a structurally well-defined metal-electrolyte interface at temperatures from 1^circ to 47^circC and reaction free energies from -1.0 to +0.8 electron volts (eV). The ferrocene group was positioned a fixed distance from the gold surface by the self-assembly of a mixed thiol monolayer of (eta^5C_5H_5)Fe(eta^5C_5H_4)CO_2(CH_2)16SH and CH_3(CH_2)15SH. Rate constants from 1 per second (s-1) to 2 x 10^4 s-1 in 1 molar HClO_4 are reasonably fit with a reorganization energy of 0.85 eV and a prefactor for electron tunneling of 7 x 10^4 s-1 eV-1. Such self-assembled monolayers can be used to systematically probe the dependence of electron-transfer rates on distance, medium, and spacer structure, and to provide an empirical basis for the construction of interfacial devices such as sensors and traosducers that utilize macroscopically directional electron-transfer reactions.

  9. Electronic Nose

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Grace Industries, Inc.'s Electronic Nose is a vapor and gas detector, deriving from NASA's electronic circuitry, capable for sensing the presence of accelerants several days after a fire. The device is powered by rechargeable battery and no special training needed to operate. If an accelerant is present, device will emit a beeping sound and trigger a flashing light; the faster the beep rate, the more volatile the accelerant. Its sensitivity can also detect minute traces of accelerants. Unit saves investigators of fire causes time and expense by providing speedy detection of physical evidence for use in court. Device is also useful for detecting hazardous fumes, locating and detecting gas leaks in refineries and on oil drilling rigs.

  10. Electronic Nose and Electronic Tongue

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, Nabarun; Bandhopadhyay, Rajib

    Human beings have five senses, namely, vision, hearing, touch, smell and taste. The sensors for vision, hearing and touch have been developed for several years. The need for sensors capable of mimicking the senses of smell and taste have been felt only recently in food industry, environmental monitoring and several industrial applications. In the ever-widening horizon of frontier research in the field of electronics and advanced computing, emergence of electronic nose (E-Nose) and electronic tongue (E-Tongue) have been drawing attention of scientists and technologists for more than a decade. By intelligent integration of multitudes of technologies like chemometrics, microelectronics and advanced soft computing, human olfaction has been successfully mimicked by such new techniques called machine olfaction (Pearce et al. 2002). But the very essence of such research and development efforts has centered on development of customized electronic nose and electronic tongue solutions specific to individual applications. In fact, research trends as of date clearly points to the fact that a machine olfaction system as versatile, universal and broadband as human nose and human tongue may not be feasible in the decades to come. But application specific solutions may definitely be demonstrated and commercialized by modulation in sensor design and fine-tuning the soft computing solutions. This chapter deals with theory, developments of E-Nose and E-Tongue technology and their applications. Also a succinct account of future trends of R&D efforts in this field with an objective of establishing co-relation between machine olfaction and human perception has been included.

  11. ELECTRONIC MULTIPLIER

    DOEpatents

    Collier, D.M.; Meeks, L.A.; Palmer, J.P.

    1961-01-31

    S>An electronic multiplier is described for use in analog computers. Two electrical input signals are received; one controls the slope of a saw-tooth voltage wave while the other controls the time duration of the wave. A condenser and diode clamps are provided to sustain the crest voltage reached by the wave, and for storing that voltage to provide an output signal which is a steady d-c voltage.

  12. ELECTRON GUN

    DOEpatents

    Christofilos, N.C.; Ehlers, K.W.

    1960-04-01

    A pulsed electron gun capable of delivering pulses at voltages of the order of 1 mv and currents of the order of 100 amperes is described. The principal novelty resides in a transformer construction which is disposed in the same vacuum housing as the electron source and accelerating electrode structure of the gun to supply the accelerating potential thereto. The transformer is provided by a plurality of magnetic cores disposed in circumferentially spaced relation and having a plurality of primary windings each inductively coupled to a different one of the cores, and a helical secondary winding which is disposed coaxially of the cores and passes therethrough in circumferential succession. Additional novelty resides in the disposition of the electron source cathode filament input leads interiorly of the transformer secondary winding which is hollow, as well as in the employment of a half-wave filament supply which is synchronously operated with the transformer supply such that the transformer is pulsed during the zero current portions of the half-wave cycle.

  13. 2016 Billion-Ton Report: Advancing Domestic Resources for a Thriving Bioeconomy, Volume 2: Environmental Sustainability Effects of Select Scenarios from Volume 1

    SciTech Connect

    Efroymson, Rebecca Ann; Langholtz, Matthew H.; Johnson, Kristen; Stokes, Bryce; Brandt, Craig C.; Davis, Maggie R.; Hellwinckel, Chad; Kline, Keith L.; Eaton, Laurence M.; Dunn, Jennifer; Canter, Christina E.; Qin, Zhangcai; Cai, Hao; Wang, Michael; Scott, D. Andrew; Jager, Henrietta I.; Wu, May; Ha, Miae; Baskaran, Latha Malar; Kreig, Jasmine A.; Rau, Benjamin; Muwamba, Augustine; Trettin, Carl; Panda, Sudhanshu; Amatya, Devendra M.; Tollner, Ernest W.; Sun, Ge; Zhang, Liangxia; Duan, Kai; Warner, Ethan; Zhang, Yimin; Inman, Daniel; Eberle, Annika; Carpenter, Alberta; Heath, Garvin; Hettinger, Dylan; Wang, Gangsheng; Sutton, Nathan J.; Busch, Ingrid Karin; Donner, Deahn M.; Wigley, T. Bently; Miller, Darren A.; Coleman, Andre; Wigmosta, Mark; Pattullo, Molly; Mayes, Melanie; Daly, Christopher; Halbleib, Mike; Negri, Cristina; Turhollow, Anthony F.; Bonner, Ian; Dale, Virginia H.

    2017-01-01

    With the goal of understanding environmental effects of a growing bioeconomy, the U.S. Department of Energy (DOE), national laboratories, and U.S. Forest Service research laboratories, together with academic and industry collaborators, undertook a study to estimate environmental effects of potential biomass production scenarios in the United States, with an emphasis on agricultural and forest biomass. Potential effects investigated include changes in soil organic carbon (SOC), greenhouse gas (GHG) emissions, water quality and quantity, air emissions, and biodiversity. Effects of altered land-management regimes were analyzed based on select county-level biomass-production scenarios for 2017 and 2040 taken from the 2016 Billion-Ton Report: Advancing Domestic Resources for a Thriving Bioeconomy (BT16), volume 1, which assumes that the land bases for agricultural and forestry would not change over time. The scenarios reflect constraints on biomass supply (e.g., excluded areas; implementation of management practices; and consideration of food, feed, forage, and fiber demands and exports) that intend to address sustainability concerns. Nonetheless, both beneficial and adverse environmental effects might be expected. To characterize these potential effects, this research sought to estimate where and under what modeled scenarios or conditions positive and negative environmental effects could occur nationwide. The report also includes a discussion of land-use change (LUC) (i.e., land management change) assumptions associated with the scenario transitions (but not including analysis of indirect LUC [ILUC]), analyses of climate sensitivity of feedstock productivity under a set of potential scenarios, and a qualitative environmental effects analysis of algae production under carbon dioxide (CO2) co-location scenarios. Because BT16 biomass supplies are simulated independent of a defined end use, most analyses do not include benefits from displacing fossil fuels or

  14. Rebalance electronics

    NASA Technical Reports Server (NTRS)

    Blalock, T. V.; Kennedy, E. J.

    1972-01-01

    Two basic types of strapdown gyroscope rebalance-electronics were analyzed and compared. These two types were a discrete-pulse ternary system and a width-modulated binary system. In the analyses, major emphasis was placed on the logic sections, the H-switches, the precision voltage reference loops, the noise performance, common-mode rejection, and loop compensation. Results of the analyses were used in identifying specific advantages and disadvantages of system details and in making accuracy and resolution comparisons. Sound engineering principles were applied in the development of both systems; however, it was concluded that each system has some disadvantages that are amenable to improvement.

  15. Neutral beamline with ion energy recovery based on magnetic blocking of electrons

    DOEpatents

    Stirling, William L.

    1982-01-01

    A neutral beamline generator with energy recovery of the full-energy ion ponent of the beam based on magnetic blocking of electrons is provided. Ions from a positive ion source are accelerated to the desired beam energy from a slightly positive potential level with respect to ground through a neutralizer cell by means of a negative acceleration voltage. The unneutralized full-energy ion component of the beam exiting the neutralizer are retarded and slightly deflected and the electrons in the neutralizer are blocked by a magnetic field generated transverse to the beamline. An electron collector in the form of a coaxial cylinder surrounding and protruding axial a few centimeters beyond the neutralizer exit terminates the electrons which exit the neutralizer in an E x B drift to the collector when the collector is biased a few hundred volts positive with respect to the neutralizer voltage. The neutralizer is operated at the negative acceleration voltage, and the deflected full energy ions are decelerated and the charge collected at ground potential thereby expending none of their energy received from the acceleration power supply.

  16. A long-lived relativistic electron storage ring embedded in Earth's Outer Van Allen belt

    DOE PAGES

    Baker, D. N.; Kanekal, S. G.; Hoxie, V. C.; ...

    2013-02-28

    Since their discovery over 50 years ago, the Earth’s Van Allen radiation belts are thought to consist of two distinct zones of trapped, highly energetic charged particles. The outer zone is comprised predominantly of mega-electron volt (MeV) electrons that wax and wane in intensity on time scales ranging from hours to days depending primarily on external forcing by the solar wind. Thus, the spatially separated inner zone is comprised of commingled high-energy electrons and very energetic positive ions (mostly protons), the latter being stable in intensity levels over years to decades. In situ energy-specific and temporally resolved spacecraft observations revealmore » an isolated third ring, or torus, of high-energy (E > 2 MeV) electrons that formed on 2 September 2012 and persisted largely unchanged in the geocentric radial range of 3.0 to ~3.5 Earth radii for over four weeks before being disrupted (and virtually annihilated) by a powerful interplanetary shock wave passage.« less

  17. Gradual Diffusion and Punctuated Phase Space Density Enhancements of Highly Relativistic Electrons: Van Allen Probes Observations

    NASA Technical Reports Server (NTRS)

    Baker, D. N.; Jaynes, A. N.; Li, X.; Henderson, M. G.; Kanekal, S. G.; Reeves, G. D.; Spence, H. E.; Claudepierre, S. G.; Fennell, J. F.; Hudson, M. K.

    2014-01-01

    The dual-spacecraft Van Allen Probes mission has provided a new window into mega electron volt (MeV) particle dynamics in the Earth's radiation belts. Observations (up to E (is) approximately 10MeV) show clearly the behavior of the outer electron radiation belt at different timescales: months-long periods of gradual inward radial diffusive transport and weak loss being punctuated by dramatic flux changes driven by strong solar wind transient events. We present analysis of multi-MeV electron flux and phase space density (PSD) changes during March 2013 in the context of the first year of Van Allen Probes operation. This March period demonstrates the classic signatures both of inward radial diffusive energization and abrupt localized acceleration deep within the outer Van Allen zone (L (is) approximately 4.0 +/- 0.5). This reveals graphically that both 'competing' mechanisms of multi-MeV electron energization are at play in the radiation belts, often acting almost concurrently or at least in rapid succession.

  18. A long-lived relativistic electron storage ring embedded in Earth's Outer Van Allen belt

    SciTech Connect

    Baker, D. N.; Kanekal, S. G.; Hoxie, V. C.; Henderson, M. G.; Li, X.; Spence, H. E.; Elkington, S. R.; Friedel, R. H. W.; Goldstein, J.; Hudson, M. K.; Reeves, G. D.; Thorne, R. M.; Kletzing, C. A.; Claudepierre, S. G.

    2013-02-28

    Since their discovery over 50 years ago, the Earth’s Van Allen radiation belts are thought to consist of two distinct zones of trapped, highly energetic charged particles. The outer zone is comprised predominantly of mega-electron volt (MeV) electrons that wax and wane in intensity on time scales ranging from hours to days depending primarily on external forcing by the solar wind. Thus, the spatially separated inner zone is comprised of commingled high-energy electrons and very energetic positive ions (mostly protons), the latter being stable in intensity levels over years to decades. In situ energy-specific and temporally resolved spacecraft observations reveal an isolated third ring, or torus, of high-energy (E > 2 MeV) electrons that formed on 2 September 2012 and persisted largely unchanged in the geocentric radial range of 3.0 to ~3.5 Earth radii for over four weeks before being disrupted (and virtually annihilated) by a powerful interplanetary shock wave passage.

  19. Auroral precipitation flux of ions and electrons in Saturn's outer magnetosphere

    NASA Astrophysics Data System (ADS)

    Barbosa, D. D.

    1990-10-01

    This paper examines particles and fields data obtained by Voyager in Saturn's outer magnetosphere with a view toward assessing the role that medium-energy ions and electrons have in stimulating the UV aurora. The magnetic field displays a high level of fluctuation of two characteristic types: large-scale coherent depressions in the field strength associated with the plumes of Titan and a small-scale incoherent turbulence presumed to be a consequence of the high-beta plasma environment. Electrons are assumed to interact strongly with lower hybrid waves and are accelerated to energies of a few kiloelectron volts. The available energy input to the aurora by protons is 5 x 10 to the 9th W, while an upper bound to that of N(+) ions is about 2 x 10 to the 10th W. Electrons in the range 1-10 keV can contribute upward of 5 x 10 to the 10th W and perhaps more if a field-aligned potential drop above the aurora is present. It is concluded that electrons are most likely the primary precipitation energy source for the aurora as a result of energy transfer from Titanogenic N(+) pickup ions in a corotation-dominated magnetosphere.

  20. Electronic Router

    NASA Technical Reports Server (NTRS)

    Crusan, Jason

    2005-01-01

    Electronic Router (E-Router) is an application program for routing documents among the cognizant individuals in a government agency or other organization. E-Router supplants a prior 14 NASA Tech Briefs, May 2005 system in which paper documents were routed physically in packages by use of paper slips, packages could be lost, routing times were unacceptably long, tracking of packages was difficult, and there was a need for much photocopying. E-Router enables a user to create a digital package to be routed. Input accepted by E-Router includes the title of the package, the person(s) to whom the package is to be routed, attached files, and comments to reviewers. Electronic mail is used to notify reviewers of needed actions. The creator of the package can, at any time, see the status of the package in the routing structure. At the end of the routing process, E-Router keeps a record of the package and of approvals and/or concurrences of the reviewers. There are commercial programs that perform the general functions of E-Router, but they are more complicated. E-Router is Web-based, easy to use, and does not require the installation or use of client software.