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1

National Compact Stellarator Experiment Project Closeout Report PROJECT CLOSEOUT REPORT  

E-Print Network [OSTI]

National Compact Stellarator Experiment Project Closeout Report i PROJECT CLOSEOUT REPORT NATIONAL of Science Princeton Plasma Physics Laboratory Oak Ridge National Laboratory #12;National Compact Stellarator Experiment Project Closeout Report PROJECT CLOSEOUT REPORT NATIONAL COMPACT STELLARATOR EXPERIMENT (NCSX

Princeton Plasma Physics Laboratory

2

Non-Linear Analysis of the Modular Coil Windings for the National Compact Stellarator Experiment  

SciTech Connect (OSTI)

A non linear FEA study has been performed on the modular coils of the National Compact Stellarator Experiment (NCSX). The modular coils provide the primary magnetic field within NCSX and consist of flexible cable conductor wound on a cast and machined winding form and vacuum impregnated with epoxy. Eighteen coils and associated winding forms are connected at assembly into a toroidal shell structure. The purpose of this study was to evaluate the structural response of the windings and shell structure during cooldown and normal operation. Two separate software packages were used for the study, and two independent analyses were undertaken. The first analysis performed with Pro/Mechanica, examined both the response of the modular coils to magnetic pressure and thermal effects during a 2 Tesla pulse. Modeled items included a portion of the shell structure the winding packs, and a set of 48 'pseudo clamps'. The so called 'pseudo clamps' are represented simply by blocks of material that are restrained in their respective normal directions and have properties which mimic the stiffness of the spring washers of the actual preload clamps. The winding pack is free to slide on the shell structure and is restrained only by the clamps. A second model, including the complete shell structure of all three coils, was studied with the FEA program ANSYS. Contact regions defined in both Pro/Mechanica and Ansys allow the winding to slide and detach form the shell structure. The two analyses are compared for parameters such as winding/structure gap, overall displacement, equivalent stress and principle strain values.

Freudenberg, K.D.; Williamson, D.E.; Fan, H.M.; Myatt, L

2005-05-15T23:59:59.000Z

3

Gyrokinetic studies of the effect of {beta} on drift-wave stability in the National Compact Stellarator Experiment  

SciTech Connect (OSTI)

The gyrokinetic turbulence code GS2 was used to investigate the effects of plasma {beta} on linear, collisionless ion temperature gradient (ITG) modes and trapped electron modes (TEM) in National Compact Stellarator Experiment (NCSX) geometry. Plasma {beta} affects stability in two ways: through the equilibrium and through magnetic fluctuations. The first was studied here by comparing ITG and TEM stability in two NCSX equilibria of differing {beta} values, revealing that the high {beta} equilibrium was marginally more stable than the low {beta} equilibrium in the adiabatic-electron ITG mode case. However, the high {beta} case had a lower kinetic-electron ITG mode critical gradient. Electrostatic and electromagnetic ITG and TEM mode growth rate dependencies on temperature gradient and density gradient were qualitatively similar. The second {beta} effect is demonstrated via electromagnetic ITG growth rates' dependency on GS2's {beta} input parameter. A linear benchmark with gyrokinetic codes GENE and GKV-X is also presented.

Baumgaertel, J. A. [Los Alamos National Laboratory, Los Alamos, New Mexico 87544 (United States); Hammett, G. W.; Mikkelsen, D. R. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States); Nunami, M. [National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan); Xanthopoulos, P. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Teilinstitut Greifswald, Wendelsteinstr. 1, 17491 Greifswald (Germany)

2012-12-15T23:59:59.000Z

4

Physics of compact stellarators* S. P. Hirshman,  

E-Print Network [OSTI]

Physics of compact stellarators* S. P. Hirshman, D. A. Spong, J. C. Whitson, B. Nelson, D. B. Redi, W. Reiersen, A. H. Reiman, J. Schmidt, R. White, and M. C. Zarnstorff Princeton Plasma Physics, Austin, Texas 78712-1081 A. Boozer Department of Applied Physics, Columbia University, New York, New York

5

THE ARIES-CS COMPACT STELLARATOR FUSION POWER PLANT  

E-Print Network [OSTI]

THE ARIES-CS COMPACT STELLARATOR FUSION POWER PLANT F. NAJMABADI* and A. R. RAFFRAY Center stellarator power plants, ARIES-CS, has been conducted to explore attrac- tive compact stellarator by earlier stellarator power plant studies had led to cost projections much higher than those of the advanced

Raffray, A. René

6

Optimization of Stellarator Reactor J. F. Lyon, Oak Ridge National Lab.  

E-Print Network [OSTI]

Optimization of Stellarator Reactor Parameters J. F. Lyon, Oak Ridge National Lab. for the ARIES was not optimized, less developed physics · LHD-based reactors also have R ~ 14 m · New optimized compact Team TOFE Meeting September 15, 2004 #12;Rationale for Compact Stellarator Reactor Study · German HSR

7

Compact Stellarator Power Plants Prospects, Technical Issue, and R&D Directions  

E-Print Network [OSTI]

1 FT/P3-13 Compact Stellarator Power Plants ­ Prospects, Technical Issue, and R&D Directions F was to investigate whether stellarator power plants can be made to be similar in size to advanced tokamak variants features as a power plant because of the lack of a large driven external current: they are inherently

Najmabadi, Farrokh

8

Exploration of Compact Stellarators as Power Plants: Initial Results from ARIES-CS Study Farrokh Najmabadi and the ARIES Team  

E-Print Network [OSTI]

Exploration of Compact Stellarators as Power Plants: Initial Results from ARIES-CS Study Farrokh study of compact stellarators as power plants, ARIES-CS, was initiated recently to advance our. It appears that devices with an overall size similar to those envisioned for tokamak power plants

California at San Diego, University of

9

Modular Dual Coolant Pb-17Li Blanket Design For ARIES-CS Compact Stellarator Power Plant  

E-Print Network [OSTI]

of the study. The preferred blanket concept is a dual coolant blanket with a He- cooled ferritic steel firstModular Dual Coolant Pb-17Li Blanket Design For ARIES-CS Compact Stellarator Power Plant X.R. Wanga from the engineering effort during the second phase of ARIES-CS study on the conceptual design

Raffray, A. René

10

Incoherent transient radio emission from stellar-mass compact objects in the SKA era  

E-Print Network [OSTI]

The universal link between the processes of accretion and ejection leads to the formation of jets and outflows around accreting compact objects. Incoherent synchrotron emission from these outflows can be observed from a wide range of accreting binaries, including black holes, neutron stars, and white dwarfs. Monitoring the evolution of the radio emission during their sporadic outbursts provides important insights into the launching of jets, and, when coupled with the behaviour of the source at shorter wavelengths, probes the underlying connection with the accretion process. Radio observations can also probe the impact of jets/outflows (including other explosive events such as magnetar giant flares) on the ambient medium, quantifying their kinetic feedback. The high sensitivity of the SKA will open up new parameter space, enabling the monitoring of accreting stellar-mass compact objects from their bright, Eddington-limited outburst states down to the lowest-luminosity quiescent levels, whose intrinsic faintnes...

Corbel, S; Fender, R P; Gallo, E; Maccarone, T J; O'Brien, T J; Paragi, Z; Rupen, M P; Rushton, A P; Sabatini, S; Sivakoff, G R; Strader, J; Woud, P A

2015-01-01T23:59:59.000Z

11

Sandia National Laboratories: Compact Linear Fesnel Reflector  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the1 -the Mid-Infrared0Energy AdvancedEnergyEnergyMappingCombustionBiofuels OnWindCompact

12

The National Compact Stellarator Experiment at the Princeton...  

Broader source: Energy.gov (indexed) [DOE]

be produced and vented to the environment during NCSX D-D operation. The annual effective dose equivalent to a hypothetical maximally exposed individual at the site boundary from...

13

PDC (polycrystalline diamond compact) bit research at Sandia National Laboratories  

SciTech Connect (OSTI)

From the beginning of the geothermal development program, Sandia has performed and supported research into polycrystalline diamond compact (PDC) bits. These bits are attractive because they are intrinsically efficient in their cutting action (shearing, rather than crushing) and they have no moving parts (eliminating the problems of high-temperature lubricants, bearings, and seals.) This report is a summary description of the analytical and experimental work done by Sandia and our contractors. It describes analysis and laboratory tests of individual cutters and complete bits, as well as full-scale field tests of prototype and commercial bits. The report includes a bibliography of documents giving more detailed information on these topics. 26 refs.

Finger, J.T.; Glowka, D.A.

1989-06-01T23:59:59.000Z

14

Compact  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation Proposed New SubstationCleanCommunity Involvement and Making aCompact soft x-ray multichord

15

The Production Phase for the National Compact Stellarator Experiment (NCSX) Modular Coil Winding Forms  

SciTech Connect (OSTI)

The production phase for the NCSX modular coil winding forms has been underway for approximately one year as of this date. This is the culmination of R&D efforts performed in 2001-4. The R&D efforts included limited manufacturing studies while NCSX was in its conceptual design phase followed by more detailed manufacturing studies by two teams which included the fabrication of full scale prototypes. This provided the foundation necessary for the production parts to be produced under a firm price and schedule contract that was issued in September 2004. This paper will describe the winding forms, the production team and team management, details of the production process, and the achievements for the first year.

Heitzenroeder, P.; Brown, T.; Neilson, G.; Malinowski, F.; Sutton, L.; Nelson, B.; Williamson, D.; Horton, N.; Goddard, B.; Edwards, J.; Bowling, K.; Hatzilias, K.

2005-10-20T23:59:59.000Z

16

Development of a compact in situ polarized {sup 3}He neutron spin filter at Oak Ridge National Laboratory  

SciTech Connect (OSTI)

We constructed a compact in situ polarized {sup 3}He neutron spin filter based on spin-exchange optical pumping which is capable of continuous pumping of the {sup 3}He gas while the system is in place in the neutron beam on an instrument. The compact size and light weight of the system simplifies its utilization on various neutron instruments. The system has been successfully tested as a neutron polarizer on the triple-axis spectrometer (HB3) and the hybrid spectrometer (HYSPEC) at Oak Ridge National Laboratory. Over 70% {sup 3}He polarization was achieved and maintained during the test experiments. Over 90% neutron polarization and an average of 25% transmission for neutrons of 14.7 meV and 15 meV was also obtained.

Jiang, C. Y.; Tong, X., E-mail: tongx@ornl.gov; Brown, D. R.; Kadron, B. J.; Robertson, J. L. [Instrument and Source Design Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Chi, S.; Christianson, A. D.; Winn, B. L. [Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

2014-07-15T23:59:59.000Z

17

THE STELLAR VELOCITY DISPERSION OF A COMPACT MASSIVE GALAXY AT z = 1.80 USING X-SHOOTER: CONFIRMATION OF THE EVOLUTION IN THE MASS-SIZE AND MASS-DISPERSION RELATIONS {sup ,}  

SciTech Connect (OSTI)

Recent photometric studies have shown that early-type galaxies at fixed stellar mass were smaller and denser at earlier times. In this Letter, we assess that finding by deriving the dynamical mass of such a compact quiescent galaxy at z = 1.8. We have obtained a high-quality spectrum with full UV-NIR wavelength coverage of galaxy NMBS-C7447 using X-Shooter on the Very Large Telescope. We determined a velocity dispersion of 294 {+-} 51 km s{sup -1}. Given this velocity dispersion and the effective radius of 1.64 {+-} 0.15 kpc (as determined from Hubble Space Telescope Wide Field Camera 3 F160W observations) we derive a dynamical mass of (1.7 {+-} 0.5) x 10{sup 11} M{sub sun}. Comparison of the full spectrum with stellar population synthesis models indicates that NMBS-C774 has a relatively young stellar population (0.40 Gyr) with little or no star formation and a stellar mass of M{sub *} {approx} 1.5 x 10{sup 11} M{sub sun}. The dynamical and photometric stellar masses are in good agreement. Thus, our study supports the conclusion that the mass densities of quiescent galaxies were indeed higher at earlier times, and this earlier result is not caused by systematic measurement errors. By combining available spectroscopic measurements at different redshifts, we find that the velocity dispersion at fixed dynamical mass was a factor of {approx}1.8 higher at z = 1.8 compared with z = 0. Finally, we show that the apparent discrepancies between the few available velocity dispersion measurements at z > 1.5 are consistent with the intrinsic scatter of the mass-size relation.

Van de Sande, Jesse; Franx, Marijn; Labbe, Ivo [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Kriek, Mariska [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Van Dokkum, Pieter G.; Bezanson, Rachel; Whitaker, Katherine E. [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States); Brammer, Gabriel [European Southern Observatory, Alonso de Cordova 3107, Casilla 19001, Vitacura, Santiago (Chile); Groot, Paul J. [Department of Astrophysics, IMAPP, Radboud University Nijmegen, P.O. Box 9010, 6500 GL Nijmegen (Netherlands); Kaper, Lex [Astronomical Institute Anton Pannekoek, University of Amsterdam, Science Park 904, 1098 XH Amsterdam (Netherlands)

2011-07-20T23:59:59.000Z

18

Collisionless microinstabilities in stellarators. II. Numerical simulations  

SciTech Connect (OSTI)

Microinstabilities exhibit a rich variety of behavior in stellarators due to the many degrees of freedom in the magnetic geometry. It has recently been found that certain stellarators (quasi-isodynamic ones with maximum-J geometry) are partly resilient to trapped-particle instabilities, because fast-bouncing particles tend to extract energy from these modes near marginal stability. In reality, stellarators are never perfectly quasi-isodynamic, and the question thus arises whether they still benefit from enhanced stability. Here, the stability properties of Wendelstein 7-X and a more quasi-isodynamic configuration, QIPC, are investigated numerically and compared with the National Compact Stellarator Experiment and the DIII-D tokamak. In gyrokinetic simulations, performed with the gyrokinetic code GENE in the electrostatic and collisionless approximation, ion-temperature-gradient modes, trapped-electron modes, and mixed-type instabilities are studied. Wendelstein 7-X and QIPC exhibit significantly reduced growth rates for all simulations that include kinetic electrons, and the latter are indeed found to be stabilizing in the energy budget. These results suggest that imperfectly optimized stellarators can retain most of the stabilizing properties predicted for perfect maximum-J configurations.

Proll, J. H. E.; Xanthopoulos, P.; Helander, P. [Max-Planck-Institut für Plasmaphysik, EURATOM Association, Teilinstitut Greifswald, Wendelsteinstraße 1, 17491 Greifswald, Germany and Max-Planck/Princeton Research Center for Plasma Physics, 17491 Greifswald (Germany)] [Max-Planck-Institut für Plasmaphysik, EURATOM Association, Teilinstitut Greifswald, Wendelsteinstraße 1, 17491 Greifswald, Germany and Max-Planck/Princeton Research Center for Plasma Physics, 17491 Greifswald (Germany)

2013-12-15T23:59:59.000Z

19

THE MASS-LOSS-INDUCED ECCENTRIC KOZAI MECHANISM: A NEW CHANNEL FOR THE PRODUCTION OF CLOSE COMPACT OBJECT-STELLAR BINARIES  

SciTech Connect (OSTI)

Over a broad range of initial inclinations and eccentricities, an appreciable fraction of hierarchical triple star systems with similar masses are essentially unaffected by the Kozai-Lidov mechanism (KM) until the primary in the central binary evolves into a compact object. Once it does, it may be much less massive than the other components in the ternary, enabling the 'eccentric Kozai mechanism (EKM)': the mutual inclination between the inner and outer binaries can flip signs driving the inner binary to very high eccentricity, leading to a close binary or collision. We demonstrate this 'mass-loss-induced eccentric Kozai' (MIEK) mechanism by considering an example system and defining an ad hoc minimal separation between the inner two members at which tidal effects become important. For fixed initial masses and semimajor axes, but uniform distributions of eccentricity and cosine of the mutual inclination, {approx}10% of systems interact tidally or collide while the primary is on the main sequence (MS) due to the KM or EKM. Those affected by the EKM are not captured by earlier quadrupole-order secular calculations. We show that fully {approx}30% of systems interact tidally or collide for the first time as the primary swells to AU scales, mostly as a result of the KM. Finally, {approx}2% of systems interact tidally or collide for the first time after the primary sheds most of its mass and becomes a white dwarf (WD), mostly as a result of the MIEK mechanism. These findings motivate a more detailed study of mass loss in triple systems and the formation of close neutron star (NS)/WD-MS and NS/WD-NS/WD binaries without an initial common envelope phase.

Shappee, Benjamin J.; Thompson, Todd A., E-mail: shappee@astronomy.ohio-state.edu, E-mail: thompson@astronomy.ohio-state.edu [Center for Cosmology, and Astro-Particle Physics, The Ohio State University, Columbus, OH 43210 (United States)

2013-03-20T23:59:59.000Z

20

Initial Activation Assessment for ARIES Compact Stellarator  

E-Print Network [OSTI]

: ­ Activity ­ Decay Heat · Address waste-related issues: ­ Waste Disposal Rating ­ Breakdown of Class A and Class C waste ­ Any cleared materials? Objectives #12;Breeder Multiplier Structure FW/Blanket Shield VV) 1h 1d 1w 1y SiC B-I FS WC SiC B-II #12;Decay Heat · SiC decay heat drops sharply after shutdown

California at San Diego, University of

Note: This page contains sample records for the topic "national compact stellarator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Stabilization of compactible waste  

SciTech Connect (OSTI)

This report summarizes the results of series of experiments performed to determine the feasibility of stabilizing compacted or compactible waste with polymers. The need for this work arose from problems encountered at disposal sites attributed to the instability of this waste in disposal. These studies are part of an experimental program conducted at Brookhaven National Laboratory (BNL) investigating methods for the improved solidification/stabilization of DOE low-level wastes. The approach taken in this study was to perform a series of survey type experiments using various polymerization systems to find the most economical and practical method for further in-depth studies. Compactible dry bulk waste was stabilized with two different monomer systems: styrene-trimethylolpropane trimethacrylate (TMPTMA) and polyester-styrene, in laboratory-scale experiments. Stabilization was accomplished by wetting or soaking compactible waste (before or after compaction) with monomers, which were subsequently polymerized. Three stabilization methods are described. One involves the in-situ treatment of compacted waste with monomers in which a vacuum technique is used to introduce the binder into the waste. The second method involves the alternate placement and compaction of waste and binder into a disposal container. In the third method, the waste is treated before compaction by wetting the waste with the binder using a spraying technique. A series of samples stabilized at various binder-to-waste ratios were evaluated through water immersion and compression testing. Full-scale studies were conducted by stabilizing two 55-gallon drums of real compacted waste. The results of this preliminary study indicate that the integrity of compacted waste forms can be readily improved to ensure their long-term durability in disposal environments. 9 refs., 10 figs., 2 tabs.

Franz, E.M.; Heiser, J.H. III; Colombo, P.

1990-09-01T23:59:59.000Z

22

Stellar models in Brane Worlds  

E-Print Network [OSTI]

We consider here a full study of stellar dynamics from the brane-world point of view in the case of constant density and of a polytropic fluid. We start our study cataloguing the minimal requirements to obtain a compact object with a Schwarszchild exterior, highlighting the low and high energy limit, the boundary conditions, and the appropriate behavior of Weyl contributions inside and outside of the star. Under the previous requirements we show an extensive study of stellar behavior, starting with stars of constant density and its extended cases with the presence of nonlocal contributions. Finally, we focus our attention to more realistic stars with a polytropic equation of state, specially in the case of white dwarfs, and study their static configurations numerically. One of the main results is that the inclusion of the Weyl functions from braneworld models allow the existence of more compact configurations than within General Relativity.

Linares, Francisco X; Ureña-Lopez, L Arturo

2015-01-01T23:59:59.000Z

23

Physics Basis for High-Beta, Low-Aspect-Ratio Stellarator Experiments  

SciTech Connect (OSTI)

High-beta, low-aspect-ratio (compact) stellarators are promising solutions to the problem of developing a magnetic plasma configuration for magnetic fusion power plants that can be sustained in steady-state without disrupting. These concepts combine features of stellarators and advanced tokamaks and have aspect ratios similar to those of tokamaks (2-4). They are based on computed plasma configurations that are shaped in three dimensions to provide desired stability and transport properties. Experiments are planned as part of a program to develop this concept. A beta = 4% quasi-axisymmetric plasma configuration has been evaluated for the National Compact Stellarator Experiment (NCSX). It has a substantial bootstrap current and is shaped to stabilize ballooning, external kink, vertical, and neoclassical tearing modes without feedback or close-fitting conductors. Quasi-omnigeneous plasma configurations stable to ballooning modes at beta = 4% have been evaluated for the Quasi-Omnigeneous Stellarator (QOS) experiment. These equilibria have relatively low bootstrap currents and are insensitive to changes in beta. Coil configurations have been calculated that reconstruct these plasma configurations, preserving their important physics properties. Theory- and experiment-based confinement analyses are used to evaluate the technical capabilities needed to reach target plasma conditions. The physics basis for these complementary experiments is described.

A. Brooks; A.H. Reiman; G.H. Neilson; M.C. Zarnstorff; et al

1999-11-01T23:59:59.000Z

24

MHD Stability Calculations of High# QuasiAxisymmetric Stellarators  

E-Print Network [OSTI]

because the net toroidal current is zero or very small. However, in high­beta compact stellarators kink modes. Most previous work has assumed cylindrical geometry and zero beta. In this work, extensive

25

MHD Stability Calculations of High-Quasi-Axisymmetric Stellarators  

E-Print Network [OSTI]

because the net toroidal current is zero or very small. However, in high-beta compact stellaratorsMHD Stability Calculations of High- Quasi-Axisymmetric Stellarators G. Y. Fu, L. P. Ku, N. Pomphrey the external kink modes. Most previous work has assumed cylindrical geometry and zero beta. In this work

26

MHD Stability Calculations of High-Quasi-Axisymmetric Stellarators  

E-Print Network [OSTI]

because the net toroidal current is zero or very small. However, in high-beta compact stellaratorsMHD Stability Calculations of High- Quasi-Axisymmetric Stellarators G. Y. Fu, L. P. Ku, N. Pomphrey kink modes. Most previous work has assumed cylindrical geometry and zero beta. In this work, extensive

27

Internship Description Title: Stellar Solutions Engineering Internship  

E-Print Network [OSTI]

Internship Description Title: Stellar Solutions ­ Engineering Internship Job Description: The internship will be held at the Stellar National Reconnaissance Office in Washington, DC. Tasks will require a background in intelligence, and familiar with all-source analysis. This internship is flexible throughout

Virginia Tech

28

Stellar jets  

E-Print Network [OSTI]

With a goal of understanding the conditions under which jets might be produced in novae and related objects, I consider the conditions under which jets are produced from other classes of accreting compact objects. I give an overview of accretion disk spectral states, including a discussion of in which states these jets are seen. I highlight the differences between neutron stars and black holes, which may help give us insights about when and how the presence of a solid surface may help or inhibit jet production.

Thomas J. Maccarone

2008-05-23T23:59:59.000Z

29

The Cooling of Compact Stars  

E-Print Network [OSTI]

The cooling of a compact star depends very sensitively on the state of dense matter at supranuclear densities, which essentially controls the neutrino emission, as well as on the structure of the stellar outer layers which control the photon emission. Open issues concern the hyperon population, the presence of meson condensates, superfluidity and superconductivity, and the transition of confined hadronic matter to quark matter. This paper describes these issues and presents cooling calculations based on a broad collection of equations of state for neutron star matter and strange matter. These results are tested against the body of observed cooling data.

Dany Page; Ulrich Geppert; Fridolin Weber

2005-08-01T23:59:59.000Z

30

STELLAR ENCOUNTER RATE IN GALACTIC GLOBULAR CLUSTERS  

SciTech Connect (OSTI)

The high stellar densities in the cores of globular clusters cause significant stellar interactions. These stellar interactions can produce close binary mass-transferring systems involving compact objects and their progeny, such as X-ray binaries and radio millisecond pulsars. Comparing the numbers of these systems and interaction rates in different clusters drives our understanding of how cluster parameters affect the production of close binaries. In this paper we estimate stellar encounter rates ({Gamma}) for 124 Galactic globular clusters based on observational data as opposed to the methods previously employed, which assumed 'King-model' profiles for all clusters. By deprojecting cluster surface brightness profiles to estimate luminosity density profiles, we treat 'King-model' and 'core-collapsed' clusters in the same way. In addition, we use Monte Carlo simulations to investigate the effects of uncertainties in various observational parameters (distance, reddening, surface brightness) on {Gamma}, producing the first catalog of globular cluster stellar encounter rates with estimated errors. Comparing our results with published observations of likely products of stellar interactions (numbers of X-ray binaries, numbers of radio millisecond pulsars, and {gamma}-ray luminosity) we find both clear correlations and some differences with published results.

Bahramian, Arash; Heinke, Craig O.; Sivakoff, Gregory R.; Gladstone, Jeanette C., E-mail: bahramia@ualberta.ca [Department of Physics, University of Alberta, CCIS 4-183, Edmonton, AB, T5K 1V4 (Canada)

2013-04-01T23:59:59.000Z

31

Interstate Oil and Gas Conservation Compact (Multiple States)  

Broader source: Energy.gov [DOE]

The Interstate Oil and Gas Compact Commission assists member states efficiently maximize oil and natural gas resources through sound regulatory practices while protecting the nation's health,...

32

Pecos River Compact (Texas)  

Broader source: Energy.gov [DOE]

This legislation authorizes the state's entrance into the Pecos River Compact, a joint agreement between the states of New Mexico and Texas. The compact is administered by the Pecos River Compact...

33

SAFETY ASSESSMENT OF THE ARIES COMPACT STELLARATOR DESIGN  

E-Print Network [OSTI]

-CS by report- ing radiological inventories, decay heat, and radioactive waste management options with bypass event that mobilizes in-vessel radioactive inventories (e.g., tritium and ero- sion dust from inventories, decay heat, and radioactive waste ~radwaste! management options ~disposal, recycling

California at San Diego, University of

34

Red River Compact (Texas)  

Broader source: Energy.gov [DOE]

The Red River Compact Commission administers the Red River Compact to ensure that Texas receives its equitable share of quality water from the Red River and its tributaries as apportioned by the...

35

Canadian River Compact (Texas)  

Broader source: Energy.gov [DOE]

The Canadian River Commission administers the Canadian River Compact which includes the states of New Mexico, Oklahoma, and Texas. Signed in 1950 by the member states, the Compact was subsequently...

36

NSTX LTXPEGASUS Compact CTF  

E-Print Network [OSTI]

isotope retention. ST-CTF Compact ST-CTF at ~ 10 MA range provide a compact nuclear component test to NSTX. Large vacuum vessel, no stabilizing plates, excellent set of profile and boundary diagnostics

Princeton Plasma Physics Laboratory

37

Testing of Compact Bolted Fasteners with Insulation and Friction-Enhanced Shims for NCSX  

SciTech Connect (OSTI)

The fastening of the National Compact Stellarator Experiment's (NCSX) modular coils presented a number of engineering and manufacturing challenges due to the high magnetic forces, need to control induced currents, tight tolerances and restrictive space envelope. A fastening method using high strength studs, jack nuts, insulating spacers, bushings and alumina coated shims was developed which met the requirements. A test program was conducted to verify the design. The tests included measurements of flatness of the spacers, determination of contact area, torque vs. tension of the studs and jack nuts, friction coefficient tests on the alumina and G-10 insulators, electrical tests, and tension relaxation tests due to temperature excursions from room temperature to liquid nitrogen temperatures. This paper will describe the design and the results of the test program.

L. E. Dudek, J.H. Chrzanowski, G. Gettelfinger, P. Heitzenroeder, S. Jurczynski, M. Viola and K. Freudenberg

2009-02-04T23:59:59.000Z

38

A technique for extending by ?10{sup 3} the dynamic range of compact proton spectrometers for diagnosing ICF implosions on the National Ignition Facility and OMEGA  

SciTech Connect (OSTI)

Wedge Range Filter (WRF) proton spectrometers are routinely used on OMEGA and the NIF for diagnosing ?R and ?R asymmetries in direct- and indirect-drive implosions of D{sup 3}He-, D{sub 2}-, and DT-gas-filled capsules. By measuring the optical opacity distribution in CR-39 due to proton tracks in high-yield applications, as opposed to counting individual tracks, WRF dynamic range can be extended by 10{sup 2} for obtaining the spectral shape, and by 10{sup 3} for mean energy (?R) measurement, corresponding to proton fluences of 10{sup 8} and 10{sup 9} cm{sup ?2}, respectively. Using this new technique, ?R asymmetries can be measured during both shock and compression burn (proton yield ?10{sup 8} and ?10{sup 12}, respectively) in 2-shock National Ignition Facility implosions with the standard WRF accuracy of ±?10 mg/cm{sup 2}.

Sio, H., E-mail: hsio@mit.edu; Séguin, F. H.; Frenje, J. A.; Gatu Johnson, M.; Zylstra, A. B.; Rinderknecht, H. G.; Rosenberg, M. J.; Li, C. K.; Petrasso, R. D. [Massachusetts Institute of Technology Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States)

2014-11-15T23:59:59.000Z

39

National Gateway GWPC/EIA  

Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]

Developing a National Gateway to oil and gas well data Interstate Oil & Gas Compact Commission Midyear Issues Summit May 19, 2014 | Biloxi, MS By Adam Sieminski, EIA Administrator...

40

Progress in the Engineering Design of the National Compact Stellarator Experiment W.T. Reiersen 1 , A. Brooks 1 , T. Brown 1 , M. Cole 2 , HM. Fan 1 , P. Goranson, P. Heitzenroeder 1 , B. Nelson 2 ,  

E-Print Network [OSTI]

transform remains monotonic with adequate reverse shear. NCSX plasma configurations are optimized (NCSX) is a proof­of­principle experiment whose objective is to demonstrate high beta operation. Many of the existing site assets including the test cell, TF and PF coils, power supplies, neutral beam

Note: This page contains sample records for the topic "national compact stellarator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Interstate Mining Compact (Maryland)  

Broader source: Energy.gov [DOE]

This legislation authorizes the state's entrance into the Interstate Mining Compact, a multi-state governmental agency / organization that represents the natural resource and related environmental...

42

Laboratory compaction of cohesionless sands  

E-Print Network [OSTI]

on the maximum dry unit weight during compaction. Three different laboratory compaction methods were used: 1) Standard Proctor', 2) Modified Proctor; and 3) Vibrating hammer. The effects of the grain size distribution, particle shape and laboratory compaction...

Delphia, John Girard

1998-01-01T23:59:59.000Z

43

An Atlas of Stellar Spectra  

E-Print Network [OSTI]

An Atlas of Stellar Spectra with an Outline of Spectral Classification ? W. W. Morgan Philip C University of California of the University of Chicago #12; An Atlas of Stellar Spectra with an Outline New York The Cambridge University Press London #12; AN ATLAS OF STELLAR SPECTRA With an Outline

Dworetsky, Mike

44

Sandia National Laboratories: compact linear Fresnel reflector  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the1development Sandia, NREL Releasehy-drogen power Portablecombustion simulationcompact

45

Sandia National Laboratories: compact toroid formation  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the1development Sandia, NREL Releasehy-drogen power Portablecombustion

46

Sandia National Laboratories: compact toroid transport  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the1development Sandia, NREL Releasehy-drogen power Portablecombustioncompact toroid

47

Sandia National Laboratories: Compact Toroid Injection project  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the1 -the Mid-Infrared0Energy AdvancedEnergyEnergyMappingCombustionBiofuels

48

Compact microchannel system  

DOE Patents [OSTI]

The present invention provides compact geometries for the layout of microchannel columns through the use of turns and straight channel segments. These compact geometries permit the use of long separation or reaction columns on a small microchannel substrate or, equivalently, permit columns of a fixed length to occupy a smaller substrate area. The new geometries are based in part on mathematical analyses that provide the minimum turn radius for which column performance in not degraded. In particular, we find that straight channel segments of sufficient length reduce the required minimum turn radius, enabling compact channel layout when turns and straight segments are combined. The compact geometries are obtained by using turns and straight segments in overlapped or nested arrangements to form pleated or coiled columns.

Griffiths, Stewart

2003-09-30T23:59:59.000Z

49

UNIFYING THE ZOO OF JET-DRIVEN STELLAR EXPLOSIONS  

SciTech Connect (OSTI)

We present a set of numerical simulations of stellar explosions induced by relativistic jets emanating from a central engine sitting at the center of compact, dying stars. We explore a wide range of durations of the central engine activity, two candidate stellar progenitors, and two possible values of the total energy release. We find that even if the jets are narrowly collimated, their interaction with the star unbinds the stellar material, producing a stellar explosion. We also find that the outcome of the explosion can be very different depending on the duration of the engine activity. Only the longest-lasting engines result in successful gamma-ray bursts. Engines that power jets only for a short time result in relativistic supernova (SN) explosions, akin to observed engine-driven SNe such as SN2009bb. Engines with intermediate durations produce weak gamma-ray bursts, with properties similar to nearby bursts such as GRB 980425. Finally, we find that the engines with the shortest durations, if they exist in nature, produce stellar explosions that lack sizable amounts of relativistic ejecta and are therefore dynamically indistinguishable from ordinary core-collapse SNe.

Lazzati, Davide; Blackwell, Christopher H. [Department of Physics, NC State University, 2401 Stinson Drive, Raleigh, NC 27695-8202 (United States); Morsony, Brian J. [Department of Astronomy, University of Wisconsin-Madison, 2535 Sterling Hall, 475 N. Charter Street, Madison WI 53706-1582 (United States); Begelman, Mitchell C. [JILA, University of Colorado, 440 UCB, Boulder, CO 80309-0440 (United States)

2012-05-01T23:59:59.000Z

50

Brookhaven National Laboratory National Synchrotron Light Source  

E-Print Network [OSTI]

Brookhaven National Laboratory National Synchrotron Light Source Number: Revision: LS-ESH-0026 4 (ANSI) Hazard Class 3B and 4 laser systems must be documented, reviewed, and approved through use) CrystaLaser Compact Solid State Laser (Class 3B) Location: All four lasers are located in the U2A

Ohta, Shigemi

51

The host galaxies of Compact Steep Spectrum and Gigahertz-Peaked Spectrum radio sources  

E-Print Network [OSTI]

I will review some of the developments in studies of the host galaxy properties of Compact Steep Spectrum (CSS) and GigaHertz-Peaked Spectrum (GPS) radio sources. In contrast to previous reviews structured around observational technique, I will discuss the host galaxy properties in terms of morphology, stellar content and warm gas properties and discuss how compact, young radio-loud AGN are key objects for understanding galaxy evolution.

J. Holt

2008-12-15T23:59:59.000Z

52

Industrial Optimization Compact Course  

E-Print Network [OSTI]

Industrial Optimization Compact Course and Challenge Workshop Optimization plays a crucial role of the processes are typically nonlinear and dyna- mic. Thus, complex dynamic optimization or optimal control in industrial optimization. February 17­20, 2014 ·9.00­17.00 IWR ·Im Neuenheimer Feld 368 ·69120 Heidelberg www

Kirches, Christian

53

The Dartmouth Stellar Evolution Database  

E-Print Network [OSTI]

The ever-expanding depth and quality of photometric and spectroscopic observations of stellar populations increase the need for theoretical models in regions of age-composition parameter space that are largely unexplored at present. Stellar evolution models that employ the most advanced physics and cover a wide range of compositions are needed to extract the most information from current observations of both resolved and unresolved stellar populations. The Dartmouth Stellar Evolution Database is a collection of stellar evolution tracks and isochrones that spans a range of [Fe/H] from -2.5 to +0.5, [alpha/Fe] from -0.2 to +0.8 (for [Fe/H] 0), and initial He mass fractions from Y=0.245 to 0.40. Stellar evolution tracks were computed for masses between 0.1 and 4 Msun, allowing isochrones to be generated for ages as young as 250 Myr. For the range in masses where the core He flash occurs, separate He-burning tracks were computed starting from the zero age horizontal branch. The tracks and isochrones have been transformed to the observational plane in a variety of photometric systems including standard UBV(RI)c, Stromgren uvby, SDSS ugriz, 2MASS JHKs, and HST ACS-WFC and WFPC2. The Dartmouth Stellar Evolution Database is accessible through a website at http://stellar.dartmouth.edu/~models/ where all tracks, isochrones, and additional files can be downloaded.

Aaron Dotter; Brian Chaboyer; Darko Jevremovic; Veselin Kostov; E. Baron; J. W. Ferguson

2008-04-28T23:59:59.000Z

54

COSMOLOGICAL SIMULATIONS OF MASSIVE COMPACT HIGH-z GALAXIES  

SciTech Connect (OSTI)

In order to investigate the structure and dynamics of the recently discovered massive (M{sub *} {approx}> 10{sup 11} M{sub sun}) compact z {approx} 2 galaxies, cosmological hydrodynamical/N-body simulations of a {approx}50,000 Mpc{sup 3} comoving (Lagrangian), proto-cluster region have been undertaken. At z = 2, the highest resolution simulation contains {approx}5800 resolved galaxies, of which 509, 27, and 5 have M{sub *}>10{sup 10} M{sub sun}, M{sub *}>10{sup 11} M{sub sun}, and M{sub *}>4 x 10{sup 11} M{sub sun}, respectively. Total stellar masses, effective radii, and characteristic stellar densities have been determined for all galaxies. At z = 2, for the definitely well-resolved mass range of M{sub *} {approx}> 10{sup 11} M{sub sun}, we fit the relation R{sub eff} = R{sub eff,12} M {sup 1/3}{sub *,12} to the data, where M{sub *,12} is the total stellar mass in units of 10{sup 12} M{sub sun}. This yields R{sub eff,12} = (1.20 {+-} 0.04) kpc, in line with observational findings for compact z {approx} 2 galaxies, though somewhat more compact than the observed average. The only line-of-sight velocity dispersion measured for a z {approx} 2 compact galaxy is very large, {sigma}{sub *,p} = 510{sup +165}{sub -95} km s{sup -1}. This value can be matched at about the 1{sigma} level, although a somewhat larger mass than the estimated M{sub *} {approx_equal} 2 x 10{sup 11} M{sub sun} is indicated. For the above mass range, the galaxies have an average axial ratio (b/a) = 0.64 {+-} 0.02 with a dispersion of 0.1, and an average rotation to one-dimensional velocity-dispersion ratio (v/{sigma}) = 0.46 {+-} 0.06 with a dispersion of 0.3, and a maximum value of v/{sigma} {approx_equal} 1.1. Both rotation and velocity anisotropy contribute significantly in flattening the compact galaxies. Some of the observed compact galaxies appear flatter than any of the simulated galaxies. Finally, it is found that the massive compact galaxies are strongly baryon dominated in their inner parts, with typical dark matter mass fractions of order only 20% inside of r = 2 R{sub eff}.

Sommer-Larsen, J.; Toft, S., E-mail: jslarsen@astro.ku.d, E-mail: sune@dark-cosmology.d [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Mariesvej 30, DK-2100 Copenhagen (Denmark)

2010-10-01T23:59:59.000Z

55

Sabine River Compact (Multiple States)  

Broader source: Energy.gov [DOE]

The Sabine River Compact Commission administers the Sabine River Compact to ensure that Texas receives its equitable share of quality water from the Sabine River and its tributaries as apportioned...

56

Strange Quark Matter and Compact Stars  

E-Print Network [OSTI]

Astrophysicists distinguish between three different types of compact stars. These are white dwarfs, neutron stars, and black holes. The former contain matter in one of the densest forms found in the Universe which, together with the unprecedented progress in observational astronomy, make such stars superb astrophysical laboratories for a broad range of most striking physical phenomena. These range from nuclear processes on the stellar surface to processes in electron degenerate matter at subnuclear densities to boson condensates and the existence of new states of baryonic matter--like color superconducting quark matter--at supernuclear densities. More than that, according to the strange matter hypothesis strange quark matter could be more stable than nuclear matter, in which case neutron stars should be largely composed of pure quark matter possibly enveloped in thin nuclear crusts. Another remarkable implication of the hypothesis is the possible existence of a new class of white dwarfs. This article aims at giving an overview of all these striking physical possibilities, with an emphasis on the astrophysical phenomenology of strange quark matter. Possible observational signatures associated with the theoretically proposed states of matter inside compact stars are discussed as well. They will provide most valuable information about the phase diagram of superdense nuclear matter at high baryon number density but low temperature, which is not accessible to relativistic heavy ion collision experiments.

Fridolin Weber

2004-09-27T23:59:59.000Z

57

Compact Spreader Schemes  

SciTech Connect (OSTI)

This paper describes beam distribution schemes adopting a novel implementation based on low amplitude vertical deflections combined with horizontal ones generated by Lambertson-type septum magnets. This scheme offers substantial compactness in the longitudinal layouts of the beam lines and increased flexibility for beam delivery of multiple beam lines on a shot-to-shot basis. Fast kickers (FK) or transverse electric field RF Deflectors (RFD) provide the low amplitude deflections. Initially proposed at the Stanford Linear Accelerator Center (SLAC) as tools for beam diagnostics and more recently adopted for multiline beam pattern schemes, RFDs offer repetition capabilities and a likely better amplitude reproducibility when compared to FKs, which, in turn, offer more modest financial involvements both in construction and operation. Both solutions represent an ideal approach for the design of compact beam distribution systems resulting in space and cost savings while preserving flexibility and beam quality.

Placidi, M.; Jung, J. -Y.; Ratti, A.; Sun, C.

2014-07-25T23:59:59.000Z

58

EXPLORING THE INTERSTELLAR MEDIA OF OPTICALLY COMPACT DWARF GALAXIES  

SciTech Connect (OSTI)

We present new Very Large Array H I spectral line, archival Sloan Digital Sky Survey, and archival Spitzer Space Telescope imaging of eight star-forming blue compact dwarf galaxies that were selected to be optically compact (optical radii <1 kpc). These systems have faint blue absolute magnitudes (M{sub B} {approx}> -17), ongoing star formation (based on emission-line selection by the H{alpha} or [O III] lines), and are nearby (mean velocity = 3315 km s{sup -1} {approx_equal} 45 Mpc). One galaxy in the sample, ADBS 113845+2008, is found to have an H I halo that extends 58 r-band scale lengths from its stellar body. In contrast, the rest of the sample galaxies have H I radii to optical-scale-length ratios ranging from 9.3 to 26. The size of the H I disk in the 'giant disk' dwarf galaxy ADBS 113845+2008 appears to be unusual as compared with similarly compact stellar populations.

Most, Hans P.; Cannon, John M.; Engstrom, Eric; Fliss, Palmer [Department of Physics and Astronomy, Macalester College, 1600 Grand Avenue, Saint Paul, MN 55105 (United States); Salzer, John J. [Department of Astronomy, Indiana University, 727 East Third Street, Bloomington, IN 47405 (United States); Rosenberg, Jessica L., E-mail: hmost@macalester.edu, E-mail: jcannon@macalester.edu, E-mail: slaz@astro.indiana.edu, E-mail: jrosenb4@gmu.edu [School of Physics, Astronomy, and Computational Science, George Mason University, Fairfax, VA 22030 (United States)

2013-06-15T23:59:59.000Z

59

Electric holding company regulation by multistate compact  

SciTech Connect (OSTI)

This article is divided into five sections. The first section discusses the market and regulatory environment of bulk power sales. The second presents the legal framework for compacting and discusses the minimal constitutional barriers presented by the Compact Clause. The next section discusses the economic considerations inherent in attempting to regulate a national activity through regional authorities. The fourth section more fully develops the administrative and political problems that regional regulation must overcome to be successful. Using the legal, economic, and policy framework developed in the preceding sections, the final section analyzes the proposal encompassed in Senate Bill 2607, a proposal by the Arkansas Public Service Commission and Entergy Corporation to create regional organizations to provide integrated resource planning.

Darr, F.P.

1993-01-01T23:59:59.000Z

60

Electron Screening Effect on Stellar Thermonuclear Fusion  

E-Print Network [OSTI]

thermonuclear fusions and show that these scenarios do not apply to stellar conditions. c ? 2013 WILEY

K. -h. Spatschek; M. Bonitz; T. Klinger; U. Ebert; C. Franck; A. V. Keudell; D. Naujoks; M. Dewitz; A. Y. Potekhin; G. Chabrier

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "national compact stellarator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Compact LINAC for deuterons  

SciTech Connect (OSTI)

We are developing a compact deuteron-beam accelerator up to the deuteron energy of a few MeV based on room-temperature inter-digital H-mode (IH) accelerating structures with the transverse beam focusing using permanent-magnet quadrupoles (PMQ). Combining electromagnetic 3-D modeling with beam dynamics simulations and thermal-stress analysis, we show that IHPMQ structures provide very efficient and practical accelerators for light-ion beams of considerable currents at the beam velocities around a few percent of the speed of light. IH-structures with PMQ focusing following a short RFQ can also be beneficial in the front end of ion linacs.

Kurennoy, S S [Los Alamos National Laboratory; O' Hara, J F [Los Alamos National Laboratory; Rybarcyk, L J [Los Alamos National Laboratory

2008-01-01T23:59:59.000Z

62

Folded Compact Range Development and Coherent Change Detection Measurement Project  

SciTech Connect (OSTI)

A novel, folded compact range configuration has been developed at the Sandia National Laboratories compact range antenna and radar cross section measurement facility, operated by the Radar/Antenna Department 2343, as a means of performing indoor, environmentally-controlled, far-field simulations of synthetic aperture radar (SAR) coherent change detection (CCD) measurements. This report describes the development of the folded compact range configuration, as well as the initial set of coherent change detection measurements made with the system. These measurements have been highly successful, and have demonstrated the viability of the folded compact range concept in simulating SAR CCD measurements. It is felt that follow-on measurements have the potential of contributing significantly to the body of knowledge available to the scientific community involved in CCD image generation and processing, and that this tool will be a significant aid in the research and development of change detection methodologies.

Sorensen, K.W.

1995-03-01T23:59:59.000Z

63

Accretion in Compact Binaries  

E-Print Network [OSTI]

Compact binaries have long been a paradigm for accretion theory. Much of our present view of how accretion occurs comes directly from the comparison of theory with observations of these sources. Since theory differs little for other objects such as active galaxies, increasing efforts have recently gone into searching for correspondences in observed behaviour. This chapter aims at giving a concise summary of the field, with particular emphasis on new developments since the previous edition of this book. These developments have been significant. Much of the earlier literature implicitly assumed that accreting binaries were fairly steady sources accreting most of the mass entering their vicinity, often with main-sequence companions, and radiating the resulting accretion luminosity in rough isotropy. We shall see that in reality these assumptions fail for the majority of systems. Most are transient; mass ejection in winds and jets is extremely common; a large (sometimes dominant) fraction of even short-period systems have evolved companions whose structure deviates significantly from the zero-age main sequence; and the radiation pattern of many objects is significantly anisotropic. It is now possible to give a complete characterization of the observed incidence of transient and persistent sources in terms of the disc instability model and formation constraints. X-ray populations in external galaxies, particularly the ultraluminous sources, are revealing important new insights into accretion processes and compact binary evolution.

Andrew R. King

2003-03-26T23:59:59.000Z

64

Susquehanna River Basin Compact (Maryland)  

Broader source: Energy.gov [DOE]

This legislation enables the state's entrance into the Susquehanna River Basin Compact, which provides for the conservation, development, and administration of the water resources of the...

65

Stellar and Intermediate-Mass Black Holes in the Milky Way and Nearby Galaxies  

SciTech Connect (OSTI)

With the advent of high resolution X-ray telescopes, the ability to identify extragalactic black holes has greatly enhanced our understanding of massive compact objects, as we are no longer limited to the rather meager Milky Way black hole population. The greatly increased numbers have opened up opportunities to find new modes of compact object accretion and potentially long-sought evidence for intermediate-mass black holes. In this lecture series, the current state of knowledge of stellar- and intermediate-mass black holes is reviewed, particularly in regards to black hole populations in external galaxies.

Irwin, Jimmy [Department of Physics and Astronomy, University of Alabama, Box 870324, Tuscaloosa, AL 35487-0324 (United States)

2010-08-09T23:59:59.000Z

66

Compact acoustic refrigerator  

DOE Patents [OSTI]

A compact acoustic refrigeration system actively cools components, e.g., electrical circuits, in a borehole environment. An acoustic engine includes first thermodynamic elements for generating a standing acoustic wave in a selected medium. An acoustic refrigerator includes second thermodynamic elements located in the standing wave for generating a relatively cold temperature at a first end of the second thermodynamic elements and a relatively hot temperature at a second end of the second thermodynamic elements. A resonator volume cooperates with the first and second thermodynamic elements to support the standing wave. To accommodate the high heat fluxes required for heat transfer to/from the first and second thermodynamic elements, first heat pipes transfer heat from the heat load to the second thermodynamic elements and second heat pipes transfer heat from first and second thermodynamic elements to the borehole environment. 18 figs.

Bennett, G.A.

1992-11-24T23:59:59.000Z

67

Compact acoustic refrigerator  

DOE Patents [OSTI]

A compact acoustic refrigeration system actively cools components, e.g., electrical circuits (22), in a borehole environment. An acoustic engine (12, 14) includes first thermodynamic elements (12) for generating a standing acoustic wave in a selected medium. An acoustic refrigerator (16, 26, 28) includes second thermodynamic elements (16) located in the standing wave for generating a relatively cold temperature at a first end of the second thermodynamic elements (16) and a relatively hot temperature at a second end of the second thermodynamic elements (16). A resonator volume (18) cooperates with the first and second thermodynamic elements (12, 16) to support the standing wave. To accommodate the high heat fluxes required for heat transfer to/from the first and second thermodynamic elements (12, 16), first heat pipes (24, 26) transfer heat from the heat load (22) to the second thermodynamic elements (16) and second heat pipes (28, 32) transfer heat from first and second thermodynamic elements (12, 16) to the borehole environment.

Bennett, Gloria A. (Los Alamos, NM)

1992-01-01T23:59:59.000Z

68

Compact vacuum insulation  

DOE Patents [OSTI]

An ultra-thin compact vacuum insulation panel is comprised of two hard, but bendable metal wall sheets closely spaced apart from each other and welded around the edges to enclose a vacuum chamber. Glass or ceramic spacers hold the wall sheets apart. The spacers can be discrete spherical beads or monolithic sheets of glass or ceramic webs with nodules protruding therefrom to form essentially "point" or "line" contacts with the metal wall sheets. In the case of monolithic spacers that form "line" contacts, two such spacers with the line contacts running perpendicular to each other form effectively "point" contacts at the intersections. Corrugations accommodate bending and expansion, tubular insulated pipes and conduits, and preferred applications are also included.

Benson, David K. (Golden, CO); Potter, Thomas F. (Denver, CO)

1993-01-01T23:59:59.000Z

69

Compact vacuum insulation embodiments  

DOE Patents [OSTI]

An ultra-thin compact vacuum insulation panel is comprised of two hard, but bendable metal wall sheets closely spaced apart from each other and welded around the edges to enclose a vacuum chamber. Glass or ceramic spacers hold the wall sheets apart. The spacers can be discrete spherical beads or monolithic sheets of glass or ceramic webs with nodules protruding therefrom to form essentially "point" or "line" contacts with the metal wall sheets. In the case of monolithic spacers that form "line" contacts, two such spacers with the line contacts running perpendicular to each other form effectively "point" contacts at the intersections. Corrugations accommodate bending and expansion, tubular insulated pipes and conduits, and preferred applications are also included.

Benson, David K. (Golden, CO); Potter, Thomas F. (Denver, CO)

1992-01-01T23:59:59.000Z

70

Compact vacuum insulation embodiments  

DOE Patents [OSTI]

An ultra-thin compact vacuum insulation panel is comprised of two hard, but bendable metal wall sheets closely spaced apart from each other and welded around the edges to enclose a vacuum chamber. Glass or ceramic spacers hold the wall sheets apart. The spacers can be discrete spherical beads or monolithic sheets of glass or ceramic webs with nodules protruding therefrom to form essentially point' or line' contacts with the metal wall sheets. In the case of monolithic spacers that form line' contacts, two such spacers with the line contacts running perpendicular to each other form effectively point' contacts at the intersections. Corrugations accommodate bending and expansion, tubular insulated pipes and conduits, and preferred applications are also included. 26 figs.

Benson, D.K.; Potter, T.F.

1992-04-28T23:59:59.000Z

71

Compact stars with a quark core within the Nambu-Jona-Lasinio (NJL) model  

SciTech Connect (OSTI)

An ultraviolet cutoff dependent on the chemical potential as proposed by Casalbuoni et al. is used in the SU(3) Nambu-Jona-Lasinio model. The model is applied to the description of stellar quark matter and compact stars. It is shown that with a new cutoff parametrization it is possible to obtain stable hybrid stars with a quark core. A larger cutoff at finite densities leads to a partial chiral symmetry restoration of quark s at lower densities. A direct consequence is the onset of the s quark in stellar matter at lower densities and a softening of the equation of state.

Lenzi, C. H. [Departamento de Fisica, Instituto Tecnologico de Aeronautica, Campo Montenegro, Sao Jose dos Campos, SP, 12228-900 (Brazil); Centro de Fisica Computacional, Department of Physics, University of Coimbra, Rua Larga, Coimbra, P-3004-516 (Portugal); Schneider, A. S. [Department of Physics, Indiana University, Swain Hall West 117, 727 East Third Street Bloomington, Indiana 47405 (United States); Providencia, C. [Centro de Fisica Computacional, Department of Physics, University of Coimbra, Rua Larga, Coimbra, P-3004-516 (Portugal); Marinho, R. M. Jr. [Departamento de Fisica, Instituto Tecnologico de Aeronautica, Campo Montenegro, Sao Jose dos Campos, SP, 12228-900 (Brazil)

2010-07-15T23:59:59.000Z

72

The stellar population of bulges  

E-Print Network [OSTI]

This review summarizes the properties of the stellar population in bulges as observed in nearby or distant spiral galaxies. It gives a particular emphasis to the comparison with elliptical galaxies, when possible. The criteria of sample selection and choices in data analysis are addressed when they may be involved in discrepant results reached by different studies.

P. Jablonka

2007-01-07T23:59:59.000Z

73

Stellar populations of bulges at low redshift  

E-Print Network [OSTI]

This chapter summarizes our current understanding of the stellar population properties of bulges and outlines important future research directions.

Sanchez-Blazquez, Patricia

2015-01-01T23:59:59.000Z

74

Compact neutron generator  

DOE Patents [OSTI]

A compact neutron generator has at its outer circumference a toroidal shaped plasma chamber in which a tritium (or other) plasma is generated. A RF antenna is wrapped around the plasma chamber. A plurality of tritium ion beamlets are extracted through spaced extraction apertures of a plasma electrode on the inner surface of the toroidal plasma chamber and directed inwardly toward the center of neutron generator. The beamlets pass through spaced acceleration and focusing electrodes to a neutron generating target at the center of neutron generator. The target is typically made of titanium tubing. Water is flowed through the tubing for cooling. The beam can be pulsed rapidly to achieve ultrashort neutron bursts. The target may be moved rapidly up and down so that the average power deposited on the surface of the target may be kept at a reasonable level. The neutron generator can produce fast neutrons from a T-T reaction which can be used for luggage and cargo interrogation applications. A luggage or cargo inspection system has a pulsed T-T neutron generator or source at the center, surrounded by associated gamma detectors and other components for identifying explosives or other contraband.

Leung, Ka-Ngo; Lou, Tak Pui

2005-03-22T23:59:59.000Z

75

Compact vacuum insulation  

DOE Patents [OSTI]

Improved compact insulation panel is provided which is comprised of two adjacent metal sheets spaced close together with a plurality of spherical, or other discretely shaped, glass or ceramic beads optimally positioned between the sheets to provide support and maintain the spacing between the metal sheets when the gases there between are evacuated to form a vacuum. These spherical glass beads provide the maximum support while minimizing thermal conductance. In its preferred embodiment; these two metal sheets are textured with ribs or concave protrusions in conjunction with the glass beads to maximize the structural integrity of the panels while increasing the spacing between beads, thereby reducing the number of beads and the number of thermal conduction paths. Glass or porcelain-enameled liners in combination with the glass spacers and metal sidewalls effectively decrease thermal conductivity, and various laminates, including wood, porcelain-enameled metal, and others effectively increase the strength and insulation capabilities of the panels. Also, a metal web is provided to hold the spacers in place, and strategic grooves are shown to accommodate expansion and contraction or shaping of the panels. 35 figs.

Benson, D.K.; Potter, T.F.

1992-10-27T23:59:59.000Z

76

Compact vacuum insulation  

DOE Patents [OSTI]

Improved compact insulation panel is provided which is comprised of two adjacent metal sheets spaced close together with a plurality of spherical, or other discretely shaped, glass or ceramic beads optimally positioned between the sheets to provide support and maintain the spacing between the metal sheets when the gases therebetween are evacuated to form a vacuum. These spherical glass beads provide the maximum support while minimizing thermal conductance. In its preferred embodiment; these two metal sheets are textured with ribs or concave protrusions in conjunction with the glass beads to maximize the structural integrity of the panels while increasing the spacing between beads, thereby reducing the number of beads and the number of thermal conduction paths. Glass or porcelain-enameled liners in combination with the glass spacers and metal sidewalls effectively decrease thermal conductivity, and variious laminates, including wood, porcelain-enameled metal, and others effectively increase the strength and insulation capabilities of the panels. Also, a metal web is provided to hold the spacers in place, and strategic grooves are shown to accommodate expansion and contraction or shaping of the panels.

Benson, David K. (Golden, CO); Potter, Thomas F. (Denver, CO)

1992-01-01T23:59:59.000Z

77

Compaction managed mirror bend achromat  

DOE Patents [OSTI]

A method for controlling the momentum compaction in a beam of charged particles. The method includes a compaction-managed mirror bend achromat (CMMBA) that provides a beamline design that retains the large momentum acceptance of a conventional mirror bend achromat. The CMMBA also provides the ability to tailor the system momentum compaction spectrum as desired for specific applications. The CMMBA enables magnetostatic management of the longitudinal phase space in Energy Recovery Linacs (ERLs) thereby alleviating the need for harmonic linearization of the RF waveform.

Douglas, David (Yorktown, VA)

2005-10-18T23:59:59.000Z

78

CAN STELLAR MIXING EXPLAIN THE LACK OF TYPE Ib SUPERNOVAE IN LONG-DURATION GAMMA-RAY BURSTS?  

SciTech Connect (OSTI)

The discovery of supernovae associated with long-duration gamma-ray burst observations is primary evidence that the progenitors of these outbursts are massive stars. One of the principle mysteries in understanding these progenitors has been the fact that all of these gamma-ray-burst-associated supernovae are Type Ic supernovae with no evidence of helium in the stellar atmosphere. Many studies have focused on whether or not this helium is simply hidden from spectral analyses. In this Letter, we show results from recent stellar models using new convection algorithms based on our current understanding of stellar mixing. We demonstrate that enhanced convection may lead to severe depletion of stellar helium layers, suggesting that the helium is not observed simply because it is not in the star. We also present light curves and spectra of these compact helium-depleted stars compared to models with more conventional helium layers.

Frey, Lucille H. [HPC-3, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Fryer, Chris L. [CCS-2, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Young, Patrick A. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85276 (United States)

2013-08-10T23:59:59.000Z

79

Yellowstone River Compact (North Dakota)  

Broader source: Energy.gov [DOE]

The Yellowstone River Compact, agreed to by the States of Montana, North Dakota, and Wyoming, provides for an equitable division and apportionment of the waters of the Yellowstone River, as well as...

80

New considerations for compact cyclotrons  

E-Print Network [OSTI]

A compact cyclotron built with superconducting magnets could be a transformative solution to many scientific problems facing the defense, medical, and energy industries today. This thesis discusses three potential applications ...

Marshall, Eric S. (Eric Scott)

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "national compact stellarator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

MESOSCALE SIMULATIONS OF POWDER COMPACTION  

SciTech Connect (OSTI)

Mesoscale 3D simulations of shock compaction of metal and ceramic powders have been performed with an Eulerian hydrocode GEODYN. The approach was validated by simulating a well-characterized shock compaction experiment of a porous ductile metal. Simulation results using the Steinberg material model and handbook values for solid 2024 aluminum showed good agreement with experimental compaction curves and wave profiles. Brittle ceramic materials are not as well studied as metals, so a simple material model for solid ceramic (tungsten carbide) has been calibrated to match experimental compaction curves. Direct simulations of gas gun experiments with ceramic powders have been performed and showed good agreement with experimental data. The numerical shock wave profile has same character and thickness as that measured experimentally using VISAR. The numerical results show reshock states above the single-shock Hugoniot line as observed in experiments. We found that for good quantitative agreement with experiments 3D simulations are essential.

Lomov, Ilya; Fujino, Don; Antoun, Tarabay; Liu, Benjamin [Lawrence Livermore National Laboratory, P. O. Box 808, Livermore CA 94551 (United States)

2009-12-28T23:59:59.000Z

82

UST_1 stellarator and status of the 3D printed UST_2 stellarator Vicente Queral L 1 UST_1 stellarator and  

E-Print Network [OSTI]

UST_1 stellarator and status of the 3D printed UST_2 stellarator Vicente Queral L 1 UST_1 stellarator and Status of the 3D printed UST_2 stellarator Vicente M. Queral* * On leave of absence from NFL and status of the 3D printed UST_2 stellarator Vicente Queral L 2 Background Basic UST_1 and UST_2 data

Columbia University

83

Modified Finch and Skea stellar model compatible with observational data  

E-Print Network [OSTI]

We present a new class of solutions to the Einstein's field equations corresponding to a static spherically symmetric anisotropic system by generalizing the ansatz of Finch and Skea [Class. Quantum Grav. 6 (1989) 467] for the gravitational potential $g_{rr}$. The anisotropic stellar model previously studied by Sharma and Ratanpal (2013) [Int. J. Mod. Phy. D 13 (2013) 1350074] is a sub-class of the solutions provided here. Based on physical requirements, regularity conditions and stability, we prescribe bounds on the model parameters. By systematically fixing values of the model parameters within the prescribed bound, we demonstrate that our model is compatible with the observed masses and radii of a wide variety of compact stars like 4U 1820-30, PSR J1903+327, 4U 1608-52, Vela X-1, PSR J1614-2230, SAX J1808.4-3658 and Her X-1.

D. M. Pandya; V. O. Thomas; R. Sharma

2014-11-20T23:59:59.000Z

84

Compact boson stars in K field theories  

E-Print Network [OSTI]

We study a scalar field theory with a non-standard kinetic term minimally coupled to gravity. We establish the existence of compact boson stars, that is, static solutions with compact support of the full system with self-gravitation taken into account. Concretely, there exist two types of solutions, namely compact balls on the one hand, and compact shells on the other hand. The compact balls have a naked singularity at the center. The inner boundary of the compact shells is singular, as well, but it is, at the same time, a Killing horizon. These singular, compact shells therefore resemble black holes.

C. Adam; N. Grandi; P. Klimas; J. Sanchez-Guillen; A. Wereszczynski

2009-09-16T23:59:59.000Z

85

Compact boson stars in K field theories  

E-Print Network [OSTI]

We study a scalar field theory with a non-standard kinetic term minimally coupled to gravity. We establish the existence of compact boson stars, that is, static solutions with compact support of the full system with self-gravitation taken into account. Concretely, there exist two types of solutions, namely compact balls on the one hand, and compact shells on the other hand. The compact balls have a naked singularity at the center. The inner boundary of the compact shells is singular, as well, but it is, at the same time, a Killing horizon. These singular, compact shells therefore resemble black holes.

Adam, C; Klimas, P; Sánchez-Guillén, J; Wereszczynski, A

2009-01-01T23:59:59.000Z

86

THE OPTICAL GREEN VALLEY VERSUS MID-INFRARED CANYON IN COMPACT GROUPS  

SciTech Connect (OSTI)

Compact groups of galaxies provide conditions similar to those experienced by galaxies in the earlier universe. Recent work on compact groups has led to the discovery of a dearth of mid-infrared transition galaxies (MIRTGs) in Infrared Array Camera (3.6-8.0 ?m) color space as well as at intermediate specific star formation rates. However, we find that in compact groups these MIRTGs have already transitioned to the optical ([g–r]) red sequence. We investigate the optical color-magnitude diagram (CMD) of 99 compact groups containing 348 galaxies and compare the optical CMD with mid-infrared (mid-IR) color space for compact group galaxies. Utilizing redshifts available from Sloan Digital Sky Survey, we identified new galaxy members for four groups. By combining optical and mid-IR data, we obtain information on both the dust and the stellar populations in compact group galaxies. We also compare with more isolated galaxies and galaxies in the Coma Cluster, which reveals that, similar to clusters, compact groups are dominated by optically red galaxies. While we find that compact group transition galaxies lie on the optical red sequence, LVL+SINGS mid-IR transition galaxies span the range of optical colors. The dearth of mid-IR transition galaxies in compact groups may be due to a lack of moderately star-forming low mass galaxies; the relative lack of these galaxies could be due to their relatively small gravitational potential wells. This makes them more susceptible to this dynamic environment, thus causing them to more easily lose gas or be accreted by larger members.

Walker, Lisa May; Butterfield, Natalie; Johnson, Kelsey; Zucker, Catherine [Astronomy Department, University of Virginia, Charlottesville, VA 22904 (United States); Gallagher, Sarah [Department of Physics and Astronomy, University of Western Ontario, London, ON N6A 3K7 (Canada); Konstantopoulos, Iraklis [Australian Astronomical Observatory, North Ryde, NSW 1670 (Australia); Zabludoff, Ann [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Hornschemeier, Ann E.; Tzanavaris, Panayiotis [Laboratory for X-Ray Astrophysics, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Charlton, Jane C. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States)

2013-10-01T23:59:59.000Z

87

Compact orthogonal NMR field sensor  

DOE Patents [OSTI]

A Compact Orthogonal Field Sensor for emitting two orthogonal electro-magnetic fields in a common space. More particularly, a replacement inductor for existing NMR (Nuclear Magnetic Resonance) sensors to allow for NMR imaging. The Compact Orthogonal Field Sensor has a conductive coil and a central conductor electrically connected in series. The central conductor is at least partially surrounded by the coil. The coil and central conductor are electrically or electro-magnetically connected to a device having a means for producing or inducing a current through the coil and central conductor. The Compact Orthogonal Field Sensor can be used in NMR imaging applications to determine the position and the associated NMR spectrum of a sample within the electro-magnetic field of the central conductor.

Gerald, II, Rex E. (Brookfield, IL); Rathke, Jerome W. (Homer Glen, IL)

2009-02-03T23:59:59.000Z

88

Abundance measurements in stellar environments  

SciTech Connect (OSTI)

Most of what we know about stars, and systems of stars, is derived from the analysis of their electromagnetic radiation. This lesson is an attempt to describe to Physicists, without any Astrophysical background, the framework to understand the present status of abundance determination in stellar environments and its limit. These notes are dedicated to the recently passed, November 21, 2013, Prof. Dimitri Mihalas who spent his life confuting the 19th century positivist philosopher Auguste Comte who stated that we shall not at all be able to determine the chemical composition of stars.

Leone, F. [Università di Catania, Dipartimento di Fisica e Astronomia, Sezione Astrofisica, Via S. Sofia 78, 95123 Catania (Italy)

2014-05-09T23:59:59.000Z

89

Stellarators | Princeton Plasma Physics Lab  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsrucLas ConchasPassiveSubmittedStatus TomAbout » Staff BasicSubcommittee onStatus of7Stellar

90

Compact accelerator for medical therapy  

DOE Patents [OSTI]

A compact accelerator system having an integrated particle generator-linear accelerator with a compact, small-scale construction capable of producing an energetic (.about.70-250 MeV) proton beam or other nuclei and transporting the beam direction to a medical therapy patient without the need for bending magnets or other hardware often required for remote beam transport. The integrated particle generator-accelerator is actuable as a unitary body on a support structure to enable scanning of a particle beam by direction actuation of the particle generator-accelerator.

Caporaso, George J.; Chen, Yu-Jiuan; Hawkins, Steven A.; Sampayan, Stephen E.; Paul, Arthur C.

2010-05-04T23:59:59.000Z

91

Compact monolithic capacitive discharge unit  

DOE Patents [OSTI]

A compact monolithic capacitive discharge unit (CDU) is disclosed in which a thyristor switch and a flyback charging circuit are both sandwiched about a ceramic energy storage capacitor. The result is a compact rugged assembly which provides a low-inductance current discharge path. The flyback charging circuit preferably includes a low-temperature co-fired ceramic transformer. The CDU can further include one or more ceramic substrates for enclosing the thyristor switch and for holding various passive components used in the flyback charging circuit. A load such as a detonator can also be attached directly to the CDU.

Roesler, Alexander W. (Tijeras, NM); Vernon, George E. (Rio Rancho, NM); Hoke, Darren A. (Albuquerque, NM); De Marquis, Virginia K. (Tijeras, NM); Harris, Steven M. (Albuquerque, NM)

2007-06-26T23:59:59.000Z

92

Helical axis stellarator with noninterlocking planar coils  

DOE Patents [OSTI]

A helical axis stellarator using only noninterlocking planar, non-circular coils, generates magnetic fields having a magnetic well and large rotational transform with resultant large equilibrium beta.

Reiman, Allan (Princeton, NJ); Boozer, Allen H. (Rocky Hill, NJ)

1987-01-01T23:59:59.000Z

93

Stellar populations in bulges of spiral galaxies  

E-Print Network [OSTI]

We discuss the integrated properties of the stellar population in bulges along the Hubble sequence and new HST data for individual stars in the bulge of M31.

P. Jablonka

1997-03-03T23:59:59.000Z

94

Flexible helical-axis stellarator  

DOE Patents [OSTI]

An 1=1 helical winding which spirals about a conventional planar, circular central conductor of a helical-axis stellarator adds a significant degree of flexibility by making it possible to control the rotational transform profile and shear of the magnetic fields confining the plasma in a helical-axis stellarator. The toroidal central conductor links a plurality of toroidal field coils which are separately disposed to follow a helical path around the central conductor in phase with the helical path of the 1=1 winding. This coil configuration produces bean-shaped magnetic flux surfaces which rotate around the central circular conductor in the same manner as the toroidal field generating coils. The additional 1=1 winding provides flexible control of the magnetic field generated by the central conductor to prevent the formation of low-order resonances in the rotational transform profile which can produce break-up of the equilibrium magnetic surfaces. Further, this additional winding can deepen the magnetic well which together with the flexible control provides increased stability.

Harris, Jeffrey H. (Oak Ridge, TN); Hender, Timothy C. (Abingdon, GB2); Carreras, Benjamin A. (Oak Ridge, TN); Cantrell, Jack L. (Oak Ridge, TN); Morris, Robert N. (Oak Ridge, TN)

1988-01-01T23:59:59.000Z

95

Hyperbolic capture of compact binaries  

E-Print Network [OSTI]

Hyperbolic encounters of compact objects are common interactions in dense environments. During this process a significant amount of gravitational radiation is emitted depending on the parameters of the system. Here we give a parametric description of the radial motion valid for general binary orbits and the radiative energy and angular momentum losses for binaries with spinning components.

Mátyás Vasúth

2014-09-23T23:59:59.000Z

96

Physics Issues in the Design of Low Aspect-Ratio, High-, Quasi-Axisymmetric Stellarators  

E-Print Network [OSTI]

, Lausanne, Switzerland 5 Max Planck Institute for Plasma Physics,Greifswald, Germany 6 Kurchatov InstitutePhysics Issues in the Design of Low Aspect-Ratio, High-, Quasi-Axisymmetric Stellarators M Princeton Plasma Physics Laboratory, Princeton, NJ 08543 USA 2 Oak Ridge National Laboratory, Oak Ridge, TN

Lin, Zhihong

97

Software Development for a CompactRIO-Based Wire Scanner Control and Data Acquisition SYstem  

SciTech Connect (OSTI)

The Beam Diagnostics and Instrumentation Team at the Los Alamos Neutron Science Center is developing a wire scanner data acquisition and control system with a National Instrument's compactRIO at its core. For this application, the compactRIO controller not only requires programming the FPGA and RT computer internal to the compactRIO, but also requires programming a client computer and a touch panel display. This article will summarize the hardware interfaces and describe the software design approach utilized for programming and interfacing the four systems together in order to fulfill the design requirements and promote reliable interoperability.

Sedillo, James Daniel [Los Alamos National Laboratory

2012-05-16T23:59:59.000Z

98

Interstate Oil and Gas Conservation Compact (Montana)  

Broader source: Energy.gov [DOE]

This legislation authorizes the State to join the Interstate Compact for the Conservation of Oil and Gas. The Compact is an agreement that has been entered into by 30 oil- and gas-producing states,...

99

Interstate Oil and Gas Conservation Compact (Maryland)  

Broader source: Energy.gov [DOE]

This legislation authorizes the State to join the Interstate Compact for the Conservation of Oil and Gas. The Compact is an agreement that has been entered into by 30 oil- and gas-producing states,...

100

ATTRACTIVE DESIGN APPROACHES FOR A COMPACT STELLARATOR POWER PLANT A.R. Raffray1  

E-Print Network [OSTI]

or liquid breeder blanket with ferritic steel; and (3) self-cooled flibe blanket with ferritic steel Phase I of the ARIES-CS study, covering the different blanket configurations and maintenance schemes will be used as the basis to down- select to a couple of combinations of blanket configuration and maintenance

California at San Diego, University of

Note: This page contains sample records for the topic "national compact stellarator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Robustness and Flexibility in Compact Quasiaxial Stellarators: Global Ideal Magnetohydrodynamic Stability and Energetic Particle Transport  

E-Print Network [OSTI]

, making use of advanced computer packages as well as high performance computing platforms. Although

Redi, Martha H.

102

Robustness and Flexibility in Compact Quasiaxial Stellarators: Global Ideal MHD Stability and Energetic Particle Transport  

E-Print Network [OSTI]

, making use of advanced computer packages as well as high performance computing platforms. Although

103

MAINTENANCE APPROACHES FOR ARIES-CS COMPACT STELLARATOR POWER CORE , S. Malang2  

E-Print Network [OSTI]

.R. Raffray1 and the ARIES Team 1 Center for Energy Research, 460 EBU-II, University of California-San Diego and maintenance ports have been conceptually defined. These are summarized in this paper. Blanket concepts of the coil system; (2) modular replacement approach through maintenance ports arranged between each pair

Raffray, A. René

104

Robustness and flexibility in compact quasiaxial stellarators: Global ideal magnetohydrodynamic stability and energetic particle transport  

E-Print Network [OSTI]

stability and energetic particle transport M. H. Redia) Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 A. Diallob) University of Montana, Missoula, Montana 59801 W. A Physics Laboratory, Princeton University, Princeton, New Jersey 08543 C. Nu¨hrenberg Max Planck Institut

105

BENEFITS OF RADIAL BUILD MINIMIZATION AND REQUIREMENTS IMPOSED ON ARIES COMPACT STELLARATOR DESIGN  

E-Print Network [OSTI]

field at the coil. During the first phase of the study, several blanket/shield systems have been considered employing advanced ferritic steel (FS) structure (such as IEA MF82H) and SiC/SiC composites-based systems (self-cooled Flibe/FS/Be and LiPb/SiC, and dual-cooled LiPb/FS/He and Li/FS/He). The newly

106

Compact neutron generator development at LBNL  

E-Print Network [OSTI]

Generator Development at LBNL J. Reijonen, G. English, R.Technology Group in LBNL. The compact axial extraction

2003-01-01T23:59:59.000Z

107

Parallization of Stellar Atmosphere Codes  

E-Print Network [OSTI]

Parallel computing has turned out to be the enabling technology to solve complex physical systems. However, the transition from shared memory, vector computers to massively parallel, distributed memory systems and, recently, to hybrid systems poses new challenges to the scientist. We want to present a cook-book (with a very strong, personal bias) based on our experience with parallization of our existing codes. Some of the general tools and communication libraries are discussed. Our approach includes a mixture of algorithm, domain and physical module based parallization. The advantages, scalability and limitations of each are discussed at some examples. We want show that it becomes easier to write parallel code with increasing complexity of the physical problem making stellar atmosphere codes beyond the classical assumptions very suitable.

P. Hoeflich

2002-09-19T23:59:59.000Z

108

Stellarmak a hybrid stellarator: Spheromak  

SciTech Connect (OSTI)

This paper discusses hybridization of modified Stellarator-like transform windings (T-windings) with a Spheromak or Field-Reversed-Mirror configuration. This configuration, Stellarmak, retains the important topological advantage of the Spheromak or FRM of having no plasma linking conductors or blankets. The T-windings provide rotational transformation in toroidal angle of the outer poloidal field lines, in effect creating a reversed B/sub Toroidal/ Spheromak or adding average B/sub T/ to the FRM producing higher shear, increased limiting ..beta.., and possibly greater stability to kinks and tilt. The presence of field ripple in the toroidal direction may be sufficient to inhibit cancellation of directed ion current by electron drag to allow steady state operation with the toroidal as well as poloidal current maintained by neutral beams.

Hartman, C.W.

1980-01-04T23:59:59.000Z

109

Mass Transfer by Stellar Wind  

E-Print Network [OSTI]

I review the process of mass transfer in a binary system through a stellar wind, with an emphasis on systems containing a red giant. I show how wind accretion in a binary system is different from the usually assumed Bondi-Hoyle approximation, first as far as the flow's structure is concerned, but most importantly, also for the mass accretion and specific angular momentum loss. This has important implications on the evolution of the orbital parameters. I also discuss the impact of wind accretion, on the chemical pollution and change in spin of the accreting star. The last section deals with observations and covers systems that most likely went through wind mass transfer: barium and related stars, symbiotic stars and central stars of planetary nebulae (CSPN). The most recent observations of cool CSPN progenitors of barium stars, as well as of carbon-rich post-common envelope systems, are providing unique constraints on the mass transfer processes.

Boffin, Henri M J

2014-01-01T23:59:59.000Z

110

Stellar Explosions by Magnetic Towers  

E-Print Network [OSTI]

We propose a magnetic mechanism for the collimated explosion of a massive star relevant for GRBs, XRFs and asymmetric supernovae. We apply Lynden-Bell's magnetic tower scenario to the interior of a massive rotating star after the core has collapsed to form a black hole with an accretion disk or a millisecond magnetar acting as a central engine. We solve the force-free Grad-Shafranov equation to calculate the magnetic structure and growth of a tower embedded in a stellar environment. The pressure of the toroidal magnetic field, continuously generated by differential rotation of the central engine, drives a rapid expansion which becomes vertically collimated after lateral force balance with the surrounding gas pressure is reached. The collimation naturally occurs because hoop stress concentrates magnetic field toward the rotation axis and inhibits lateral expansion. This leads to the growth of a self-collimated magnetic tower. When embedded in a massive star, the supersonic expansion of the tower drives a strong bow shock behind which an over-pressured cocoon forms. The cocoon confines the tower by supplying collimating pressure and provides stabilization against disruption due to MHD instabilities. Because the tower consists of closed field lines starting and ending on the central engine, mixing of baryons from the cocoon into the tower is suppressed. The channel cleared by the growing tower is thus plausibly free of baryons and allows the escape of magnetic energy from the central engine through the star. While propagating down the stellar density gradient, the tower accelerates and becomes relativistic. During the expansion, fast collisionless reconnection becomes possible resulting in dissipation of magnetic energy which may be responsible for GRB prompt emission.

Dmitri A. Uzdensky; Andrew I. MacFadyen

2006-05-05T23:59:59.000Z

111

Proceedings of US-Japan heliotron-stellarator workshop: Volume 3  

SciTech Connect (OSTI)

This paper is the third of four volumes on the US-Japan Heliotron-Stellarator Workshop. It contains talks on the following: Heliotron EICRF Heating Experiment; CHS Heating Systems (NBI, ECH, ICH); ICH Program for ATF; ICRF Wave Propagation; the HBQM Heliac Work; configuration studies; compact torsatron studies; low aspect ratio torsatron design; optimized small stellarator designs; configuration studies for ATF; currents in ATF; currents in ATF; computations of 3-D equilibria with islands; magnetic surface mapping studies; magnetic field alignment and mapping on ATF; divertor experiments in IMS; PMI program and wall conditioning for ATF; hard X-ray suppression on ATF; plasma rotation and potential measurement; and status of heavy ion beam probe for ATF.

Not Available

1987-01-01T23:59:59.000Z

112

Compact magnetic energy storage module  

DOE Patents [OSTI]

A superconducting compact magnetic energy storage module in which a plurality of superconducting toroids, each having a toroidally wound superconducting winding inside a poloidally wound superconducting winding, are stacked so that the flow of electricity in each toroidally wound superconducting winding is in a direction opposite from the direction of electrical flow in other contiguous superconducting toroids. This allows for minimal magnetic pollution outside of the module.

Prueitt, Melvin L. (Los Alamos, NM)

1994-01-01T23:59:59.000Z

113

Compact magnetic energy storage module  

DOE Patents [OSTI]

A superconducting compact magnetic energy storage module in which a plurality of superconducting toroids, each having a toroidally wound superconducting winding inside a poloidally wound superconducting winding, are stacked so that the flow of electricity in each toroidally wound superconducting winding is in a direction opposite from the direction of electrical flow in other contiguous superconducting toroids. This allows for minimal magnetic pollution outside of the module. 4 figures.

Prueitt, M.L.

1994-12-20T23:59:59.000Z

114

Captures of stars by a massive black hole: Investigations in numerical stellar dynamics  

E-Print Network [OSTI]

Among the astrophysical systems targeted by LISA, stars on relativistic orbits around massive black holes (MBHs) are particularly promising sources. Unfortunately, the prediction for the number and characteristics of such sources suffers from many uncertainties. Stellar dynamical Monte Carlo simulations of the evolution of galactic nucleus models allow more realistic estimates of these quantities. The computations presented here strongly suggest that the closest such extreme mass-ratio binary to be detected by LISA could be a low-mass MS star (MSS) orbiting the MBH at the center of our Milky Way. Only compact stars contribute to the expected detections from other galaxies because MSSs are disrupted by tidal forces too early.

Marc Freitag

2003-06-03T23:59:59.000Z

115

Electron screening effect on stellar thermonuclear fusion  

E-Print Network [OSTI]

We study the impact of plasma correlation effects on nonresonant thermonuclear reactions for various stellar objects, namely in the liquid envelopes of neutron stars, and the interiors of white dwarfs, low-mass stars, and substellar objects. We examine in particular the effect of electron screening on the enhancement of thermonuclear reactions in dense plasmas within and beyond the linear mixing rule approximation as well as the corrections due to quantum effects at high density. In addition, we examine some recent unconventional (Yukawa-potential and "quantum-tail") theoretical results on stellar thermonuclear fusions and show that these scenarios do not apply to stellar conditions.

Potekhin, A Y

2013-01-01T23:59:59.000Z

116

Supernova rates and stellar populations  

E-Print Network [OSTI]

We discuss the results about the nature of type Ia Supernovae that can be derived by studying their rates in different stellar populations. While the evolution of SN photometry and spectra can constrain the explosion mechanism, the SN rate depends on the progenitor system. We review the current available data on rates as a function of parent galaxy color, morphology, star formation rate, radio luminosity and environment. By studying the variation of the rates with the color of the parent galaxy, a strong evidence was established that type Ia SNe come from both young and old stars. The dependence of the rates with the radio power of the parent galaxy is best reproduced by a bimodal distribution of delay time between the formation of the progenitor and its explosion as a SN. Cluster early-type galaxies show higher type Ia SN rate with respect to field galaxies, and this effect can be due either to traces of young stars or to differences in the delay time distribution.

F. Mannucci

2007-08-03T23:59:59.000Z

117

Stellar Populations in Bulges of Spiral Galaxies  

E-Print Network [OSTI]

We have conducted a spectroscopic analysis of the bulges of a sample of 31 spiral galaxies, spanning the Hubble sequence from S0 to Scd type, in order to study the radial distribution of their stellar population properties.

P. Jablonka; J. Gorgas; P. Goudfrooij

2002-02-01T23:59:59.000Z

118

Calibration for Frequencies of Stellar Spectral Lines  

E-Print Network [OSTI]

of the luminosity distance to extragalactic sources with known redshifts. These methods, which make assumptions about the luminosity of the stellar sources, are often affected by the uncertainties in measurements or by evolutionary effects. As the universe...

Gomez, Juana

2010-07-14T23:59:59.000Z

119

Compact bilinear operators and commutators  

E-Print Network [OSTI]

) For all bounded B1 ? X,B2 ? Y , T (B1 ×B2) is precompact. (c7) For all bounded sequences {(xn, yn)} ? X × Y , the sequence {T (xn, yn)} has a convergent subsequence. Furthermore, if Z is Banach, then (c1) is also equivalent to: (c8) For all bounded B ? X...(X ×Y, Z) ? B(X ×Y, Z), assume that the compact bilinear operator T is not bounded. Then, for some r > 0, there exists a sequence (xn, yn) ? Br,X×Y , and ?T (xn, yn)? ? ?. Thus, {T (xn, yn)} could not have a convergent subsequence, so T (Br,X×Y ) would...

Bé nyi, Á rpá d; Torres, Rodolfo H.

2013-07-01T23:59:59.000Z

120

Compact submanifolds supporting singular interactions  

SciTech Connect (OSTI)

A quantum particle moving under the influence of singular interactions on embedded surfaces furnish an interesting example from the spectral point of view. In these problems, the possible occurrence of a bound-state is perhaps the most important aspect. Such systems can be introduced as quadratic forms and generically they do not require renormalization. Yet an alternative path through the resolvent is also beneficial to study various properties. In the present work, we address these issues for compact surfaces embedded in a class of ambient manifolds. We discover that there is an exact bound state solution written in terms of the heat kernel of the ambient manifold for a range of coupling strengths. Moreover, we develop techniques to estimate bounds on the ground state energy when several surfaces, each of which admits a bound state solution, coexist. -- Highlights: •Schrödinger operator with singular interactions supported on compact submanifolds. •Exact bound-state solution in terms of the heat kernel of the ambient manifold. •Generalization of the variational approach to a collection of submanifolds. •Existence of a lower bound for a unique ground state energy.

Kaynak, Burak Tevfik, E-mail: burak.kaynak@boun.edu.tr; Teoman Turgut, O., E-mail: turgutte@boun.edu.tr

2013-12-15T23:59:59.000Z

Note: This page contains sample records for the topic "national compact stellarator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Compacted carbon for electrochemical cells  

DOE Patents [OSTI]

This invention provides compacted carbon that is useful in the electrode of an alkali metal/carbon electrochemical cell of improved capacity selected from the group consisting of: (a) coke having the following properties: (1) an x-ray density of at least 2.00 grams per cubic centimeters, (2) a closed porosity of no greater than 5%, and (3) an open porosity of no greater than 47%; and (b) graphite having the following properties: (1) an x-ray density of at least 2.20 grams per cubic centimeters, (2) a closed porosity of no greater than 5%, and (3) an open porosity of no greater than 25%. This invention also relates to an electrode for an alkali metal/carbon electrochemical cell comprising compacted carbon as described above and a binder. This invention further provides an alkali metal/carbon electrochemical cell comprising: (a) an electrode as described above, (b) a non-aqueous electrolytic solution comprising an organic aprotic solvent and an electrolytically conductive salt and an alkali metal, and (c) a counter electrode. 10 figs.

Greinke, R.A.; Lewis, I.C.

1997-10-14T23:59:59.000Z

122

Hydrostatic compaction of Microtherm HT.  

SciTech Connect (OSTI)

Two samples of jacketed Microtherm{reg_sign}HT were hydrostatically pressurized to maximum pressures of 29,000 psi to evaluate both pressure-volume response and change in bulk modulus as a function of density. During testing, each of the two samples exhibited large irreversible compactive volumetric strains with only small increases in pressure; however at volumetric strains of approximately 50%, the Microtherm{reg_sign}HT stiffened noticeably at ever increasing rates. At the maximum pressure of 29,000 psi, the volumetric strains for both samples were approximately 70%. Bulk modulus, as determined from hydrostatic unload/reload loops, increased by more than two-orders of magnitude (from about 4500 psi to over 500,000 psi) from an initial material density of {approx}0.3 g/cc to a final density of {approx}1.1 g/cc. An empirical fit to the density vs. bulk modulus data is K = 492769{rho}{sup 4.6548}, where K is the bulk modulus in psi, and {rho} is the material density in g/cm{sup 3}. The porosity decreased from 88% to {approx}20% indicating that much higher pressures would be required to compact the material fully.

Broome, Scott Thomas; Bauer, Stephen J.

2010-09-01T23:59:59.000Z

123

Method for preparing porous metal hydride compacts  

DOE Patents [OSTI]

A method for preparing porous metallic-matrix hydride compacts which can be repeatedly hydrided and dehydrided without disintegration. A mixture of a finely divided metal hydride and a finely divided matrix metal is contacted with a poison which prevents the metal hydride from dehydriding at room temperature and atmospheric pressure. The mixture of matrix metal and poisoned metal hydride is then compacted under pressure at room temperature to form porous metallic-matrix hydride compacts.

Ron, M.; Gruen, D.M.; Mendelsohn, M.H.; Sheft, I.

1980-01-21T23:59:59.000Z

124

Method for preparing porous metal hydride compacts  

DOE Patents [OSTI]

A method for preparing porous metallic-matrix hydride compacts which can be repeatedly hydrided and dehydrided without disintegration. A mixture of a finely divided metal hydride and a finely divided matrix metal is contacted with a poison which prevents the metal hydride from dehydriding at room temperature and atmospheric pressure. The mixture of matrix metal and poisoned metal hydride is then compacted under pressure at room temperature to form porous metallic-matrix hydride compacts.

Ron, Moshe (Haifa, IL); Gruen, Dieter M. (Downers Grove, IL); Mendelsohn, Marshall H. (Woodridge, IL); Sheft, Irving (Oak Park, IL)

1981-01-01T23:59:59.000Z

125

On compact generation of deformed schemes.  

E-Print Network [OSTI]

We obtain a theorem which allows to prove compact generation of derived categories of Grothendieck categories, based upon certain coverings by localizations. This theorem follows from an application of Rouquier's cocovering theorem in the triangulated context, and it implies Neeman's result on compact generation of quasi-compact separated schemes. We prove an application of our theorem to non-commutative deformations of such schemes, based upon a change from Koszul complexes to Chevalley-Eilenberg complexes.

Wendy Lowen; Michel Van den Bergh

126

Interstate Mining Compact Commission (multi-state)  

Broader source: Energy.gov [DOE]

The Interstate Mining Compact is a multi-state governmental agency / organization that represents the natural resource and related environmental protection interests of its member states. Currently...

127

Covered Product Category: Compact Fluorescent Lamps  

Broader source: Energy.gov [DOE]

FEMP provides acquisition guidance across a variety of product categories, including compact fluorescent lamps (CFLs), which are an ENERGY STAR-qualified product category.

128

Convolution type operators on locally compact groups  

E-Print Network [OSTI]

Shtein--~erg, Convolution Type Operators on Locally Compact Groups [in Russian],. Manuscript Deposited in the All-Union Institute of Scientific and Technical ...

129

Compact Solid State Cooling Systems: Compact MEMS Electrocaloric Module  

SciTech Connect (OSTI)

BEETIT Project: UCLA is developing a novel solid-state cooling technology to translate a recent scientific discovery of the so-called giant electrocaloric effect into commercially viable compact cooling systems. Traditional air conditioners use noisy, vapor compression systems that include a polluting liquid refrigerant to circulate within the air conditioner, absorb heat, and pump the heat out into the environment. Electrocaloric materials achieve the same result by heating up when placed within an electric field and cooling down when removed—effectively pumping heat out from a cooler to warmer environment. This electrocaloric-based solid state cooling system is quiet and does not use liquid refrigerants. The innovation includes developing nano-structured materials and reliable interfaces for heat exchange. With these innovations and advances in micro/nano-scale manufacturing technologies pioneered by semiconductor companies, UCLA is aiming to extend the performance/reliability of the cooling module.

None

2010-10-01T23:59:59.000Z

130

Compacted Soil Liner Interface Strength Importance  

E-Print Network [OSTI]

Case Study Compacted Soil Liner Interface Strength Importance Timothy D. Stark, F.ASCE1 ; Hangseok interface is not the geomembrane (GM)/compacted low-permeability soil liner (LPSL) but a soil­soil interface placing the cover soil from bottom to top. DOI: 10.1061/(ASCE)GT.1943-5606 .0000556. © 2012 American

131

Non-compact versions of Edwards' Theorem  

E-Print Network [OSTI]

Edwards' Theorem establishes duality between a convex cone in the space of continuous functions on a compact space and the set of representing or Jensen measures for this cone. In this paper we prove non-compact versions of this theorem.

Gogus, Nihat G; Poletsky, Evgeny A

2010-01-01T23:59:59.000Z

132

3D N = 4 Gauge Theory Compactication  

E-Print Network [OSTI]

Outline 3D N = 4 Gauge Theory Compactication Twistors 3D N = 4 Supersymmetric Gauge Theories and Hyperk¨ahler Metrics Richard Eager UCSB Friday, October 17th, 2008, 4:00 p.m. Richard Eager UCSB 3D N = 4 Supersymmetric Gauge Theories and Hyperk¨ahler M #12;Outline 3D N = 4 Gauge Theory Compactication Twistors

Bigelow, Stephen

133

Keck-I MOSFIRE spectroscopy of compact star-forming galaxies at z$\\gtrsim$2: High velocity dispersions in progenitors of compact quiescent galaxies  

E-Print Network [OSTI]

We present Keck-I MOSFIRE near-infrared spectroscopy for a sample of 13 compact star-forming galaxies (SFGs) at redshift $2\\leq z \\leq2.5$ with star formation rates of SFR$\\sim$100M$_{\\odot}$ y$^{-1}$ and masses of log(M/M$_{\\odot}$)$\\sim10.8$. Their high integrated gas velocity dispersions of $\\sigma_{\\rm{int}}$=230$^{+40}_{-30}$ km s$^{-1}$, as measured from emission lines of H$_{\\alpha}$ and [OIII], and the resultant M$_{\\star}-\\sigma_{\\rm{int}}$ relation and M$_{\\star}$$-$M$_{\\rm{dyn}}$ all match well to those of compact quiescent galaxies at $z\\sim2$, as measured from stellar absorption lines. Since log(M$_{\\star}$/M$_{\\rm{dyn}}$)$=-0.06\\pm0.2$ dex, these compact SFGs appear to be dynamically relaxed and more evolved, i.e., more depleted in gas and dark matter ($infusion of external gas, depletion timescales are short, less than $\\sim$300 Myr. This discovery adds another link to our new dynamical chain of evidence...

Barro, G; Koo, D C; Dekel, A; Kassin, S A; Kocevski, D D; Faber, S M; van der Wel, A; Guo, Y; Perez-Gonzalez, P G; Toloba, E; Fang, J J; Pacifici, C; Simons, R; Campbell, R D; Ceverino, D; Finkelstein, S L; Goodrich, B; Kassis, M; Koekemoer, A M; Konidaris, N P; Livermore, R C; Lyke, J E; Mobasher, B; Nayyeri, H; Peth, M; Primack, J R; Rizzi, L; Somerville, R S; Wirth, G D; Zolotov, A

2014-01-01T23:59:59.000Z

134

Recent advances in modeling stellar interiors (u)  

SciTech Connect (OSTI)

Advances in stellar interior modeling are being driven by new data from large-scale surveys and high-precision photometric and spectroscopic observations. Here we focus on single stars in normal evolutionary phases; we will not discuss the many advances in modeling star formation, interacting binaries, supernovae, or neutron stars. We review briefly: (1) updates to input physics of stellar models; (2) progress in two and three-dimensional evolution and hydrodynamic models; (3) insights from oscillation data used to infer stellar interior structure and validate model predictions (asteroseismology). We close by highlighting a few outstanding problems, e.g., the driving mechanisms for hybrid {gamma} Dor/{delta} Sct star pulsations, the cause of giant eruptions seen in luminous blue variables such as {eta} Car and P Cyg, and the solar abundance problem.

Guzik, Joyce Ann [Los Alamos National Laboratory

2010-01-01T23:59:59.000Z

135

Electron capture cross sections for stellar nucleosynthesis  

E-Print Network [OSTI]

In the first stage of this work, we perform detailed calculations for the cross sections of the electron capture on nuclei under laboratory conditions. Towards this aim we exploit the advantages of a refined version of the proton-neutron quasi-particle random-phase approximation (pn-QRPA) and carry out state-by-state evaluations of the rates of exclusive processes that lead to any of the accessible transitions within the chosen model space. In the second stage of our present study, we translate the above mentioned $e^-$-capture cross sections to the stellar environment ones by inserting the temperature dependence through a Maxwell-Boltzmann distribution describing the stellar electron gas. As a concrete nuclear target we use the $^{66}Zn$ isotope, which belongs to the iron group nuclei and plays prominent role in stellar nucleosynthesis at core collapse supernovae environment.

Giannaka, P G

2015-01-01T23:59:59.000Z

136

Ultra-Compact H II Regions and the Early Lives of Massive Stars  

E-Print Network [OSTI]

We review the phenomenon of ultra-compact H II regions (UCHIIs) as a key phase in the early lives of massive stars. This most visible manifestation of massive star formation begins when the Lyman continuum output from the massive young stellar object becomes sufficient to ionize the surroundings from which it was born. Knowledge of this environment is gained through an understanding of the morphologies of UCHII regions and we examine the latest developments in deep radio and mid-IR imaging. SPITZER data from the GLIMPSE survey are an important new resource in which PAH emission and the ionizing stars can be seen. We review the role played by strong stellar winds from the central stars in sweeping out central cavities and causing the limb-brightened appearance. A range of evidence from velocity structure, proper motions, the molecular environment and recent hydrodynamical modeling indicates that cometary UCHII regions require a combination of champagne flow and bow shock motion. Finally, we discuss the class of hyper-compact H II regions or broad recombination line objects. They are likely to mark the transition soon after the breakout of the Lyman continuum radiation from the young star. Models for these objects are presented, including photo-evaporating disks and ionized accretion flows that are gravitationally trapped. Evolutionary scenarios tracing young massive stars passage through these ionized phases are discussed.

M. G. Hoare; S. E. Kurtz; S. Lizano; E. Keto; P. Hofner

2006-03-21T23:59:59.000Z

137

From Ultracompact to Extended HII Regions. II: Cloud Gravity and Stellar Motion  

E-Print Network [OSTI]

The dynamical evolution of HII regions with and without stellar motion in dense, structured molecular clouds is studied. Clouds are modeled in hydrostatic equilibrium, with gaussian central cores and external halos that obey r**-2 and r**-3 density power laws. The cloud gravity is included as a time-independent, external force. Stellar velocities of 0, 2, 8, and 12 km/s are considered. When stellar motion is included, stars move from the central core to the edge of the cloud, producing transitions from ultracompact to extended HII regions as the stars move into lower density regions. The opposite behavior occurs when stars move toward the cloud cores. The main conclusion of our study is that ultracompact HII regions are pressure-confined entities while they remain embedded within dense cores. The confinement comes from ram and/or ambient pressures. The survival of ultracompact regions depends on the position of the star with respect to the core, the stellar life-time, and the core crossing time. Stars with velocities less than the cloud dispersion velocity can produce cometary shapes smaller than 0.1 pc at times of 20,000 yr or more. The sequence Ultracompact to Compact to Extended HII region shows a variety of unpredictable structures due to ionization-shock front instability. Some ultracompact HII regions with a core-halo morphology might be explained by self-blocking effects, when stars overtake and ionize leading, piled-up clumps of neutral gas. We use thermal energy to support the cloud against gravity; the results remain the same if other types of isotropic cloud support are used.

Jose Franco; Guillermo Garcia-Segura; Stan Kurtz

2005-08-22T23:59:59.000Z

138

A compact tritium AMS system  

SciTech Connect (OSTI)

Tritium ({sup 3}H) is a radioisotope that is extensively utilized in biological and environmental research. For biological research, {sup 3}H is generally quantified by liquid scintillation counting requiring gram-sized samples and counting times of several hours. For environmental research, {sup 3}H is usually quantified by {sup 3}He in-growth which requires gram-sized samples and in-growth times of several months. In contrast, provisional studies at LLNL's Center for Accelerator Mass Spectrometry have demonstrated that Accelerator Mass Spectrometry (AMS) can be used to quantify {sup 3}H in milligram-sized biological samples with a 100 to 1000-fold improvement in detection limits when compared to scintillation counting. This increased sensitivity is expected to have great impact in the biological and environmental research community. However in order to make the {sup 3}H AMS technique more broadly accessible, smaller, simpler, and less expensive AMS instrumentation must be developed. To meet this need, a compact, relatively low cost prototype {sup 3}H AMS system has been designed and built based on a LLNL ion source/sample changer and an AccSys Technology, Inc. Radio Frequency Quadrupole (RFQ) linac. With the prototype system, {sup 3}/{sup 1}H ratios ranging from 1 x 10{sup -10} to 1 x 10{sup -13} have to be measured from milligram sized samples. With improvements in system operation and sample preparation methodology, the sensitivity limit of the system is expected to increase to approximately 1 x 10{sup -15}.

Chiarappa, M L; Dingley, K H; Hamm, R W; Love, A H; Roberts, M L

1999-09-23T23:59:59.000Z

139

NUCLEAR ASPECTS OF STELLAR AND EXPLOSIVE NUCLEOSYNTHESIS  

E-Print Network [OSTI]

NUCLEAR ASPECTS OF STELLAR AND EXPLOSIVE NUCLEOSYNTHESIS Thomas Rauscher 1 , Friedrich. of Astron. and Astroph., Univ. of California, Santa Cruz, CA 95064 Abstract The majority of nuclear­Feshbach). The global parametrizations of the nuclear properties needed for predictions far off stability probe our

Rauscher, Thomas

140

EXPLORING THE MORPHOLOGY OF RAVE STELLAR SPECTRA  

SciTech Connect (OSTI)

The RAdial Velocity Experiment (RAVE) is a medium-resolution (R {approx} 7500) spectroscopic survey of the Milky Way that has already obtained over half a million stellar spectra. They present a randomly selected magnitude-limited sample, so it is important to use a reliable and automated classification scheme that identifies normal single stars and discovers different types of peculiar stars. To this end, we present a morphological classification of {approx}350, 000 RAVE survey stellar spectra using locally linear embedding, a dimensionality reduction method that enables representing the complex spectral morphology in a low-dimensional projected space while still preserving the properties of the local neighborhoods of spectra. We find that the majority of all spectra in the database ({approx} 90%-95%) belong to normal single stars, but there is also a significant population of several types of peculiars. Among them, the most populated groups are those of various types of spectroscopic binary and chromospherically active stars. Both of them include several thousands of spectra. Particularly the latter group offers significant further investigation opportunities since activity of stars is a known proxy of stellar ages. Applying the same classification procedure to the sample of normal single stars alone shows that the shape of the projected manifold in two-dimensional space correlates with stellar temperature, surface gravity, and metallicity.

Matijevic, G.; Zwitter, T. [Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana (Slovenia); Bienayme, O.; Siebert, A. [Observatoire de Strasbourg, Universite de Strasbourg, CNRS, 11 rue de l'universite, 67000 Strasbourg (France); Bland-Hawthorn, J. [Sydney Institute for Astronomy, University of Sydney, NSW 2006 (Australia); Boeche, C.; Grebel, E. K. [Astronomisches Rechen-Institut, Zentrum fuer Astronomie der Universitaet Heidelberg, Moenchhofstr. 12-14, 69120 Heidelberg (Germany); Freeman, K. C. [Research School of Astronomy and Astrophysics, Australia National University, Weston Creek, Canberra, ACT 2611 (Australia); Gibson, B. K. [Jeremiah Horrocks Institute, University of Central Lancashire, Preston PR1 3TE (United Kingdom); Gilmore, G. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Helmi, A. [Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, 9700 AV Groningen (Netherlands); Munari, U. [INAF Osservatorio Astronomico di Padova, 36012 Asiago (Italy); Navarro, J. [Department of Physics and Astronomy, University of Victoria, Victora, BC V8P 5C2 (Canada); Parker, Q. A.; Reid, W. [Department of Physics and Astronomy, Macquarie University, NSW 2109 (Australia); Seabroke, G. [Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking RH5 6NT (United Kingdom); Siviero, A. [Department of Astronomy, Padova University, Vicolo dell'Osservatorio 2, 35122 Padova (Italy); Steinmetz, M.; Williams, M. [Leibniz-Institut fuer Astrophysik Potsdam (AIP), An der Sternwarte 16, 14482 Potsdam (Germany); Watson, F. G., E-mail: gal.matijevic@fmf.uni-lj.si [Australian Astronomical Observatory, P.O. Box 296, Epping, NSW 2121 (Australia); and others

2012-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "national compact stellarator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Helical axis stellarator with noninterlocking planar coils  

DOE Patents [OSTI]

The present invention generates stellarator fields having favorable properties (magnetic well and large rotational transform) by a simple coil system consisting only of unlinked planar non-circular coils. At large rotational transform toroidal effects on magnetic well and rotational transform are small and can be ignored. We do so herein, specializing in straight helical systems.

Reiman, A.; Boozer, A.H.

1984-03-06T23:59:59.000Z

142

Compact, electro-hydraulic, variable valve actuation system providing...  

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

Compact, electro-hydraulic, variable valve actuation system providing variable lift, timing and duration to enable high efficiency engine combustion control Compact,...

143

Development of Compact Gaseous Sensors with Internal Reference...  

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

Compact Gaseous Sensors with Internal Reference for Monitoring O2 and NOx in Combustion Environments Development of Compact Gaseous Sensors with Internal Reference for Monitoring...

144

Micro- & Nano-Technologies Enabling More Compact, Lightweight...  

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

Micro- & Nano-Technologies Enabling More Compact, Lightweight Thermoelectric Power Generation & Cooling Systems Micro- & Nano-Technologies Enabling More Compact, Lightweight...

145

Heart of Darkness: dust obscuration of the central stellar component in globular clusters younger than ~100Myr in multiple stellar population models  

E-Print Network [OSTI]

To explain the observed anomalies in stellar populations within globular clusters, many globular cluster formation theories require two independent episodes of star formation. A fundamental prediction of these models is that the clusters must accumulate large gas reservoirs as the raw material to form the second stellar generation. We show that young clusters containing the required gas reservoir should exhibit the following observational signatures: (i) a dip in the measured luminosity profile or an increase in measured reddening towards the cluster centre, with Av >10mag within a radius of a few pc; (ii) bright (sub)mm emission from dust grains; (iii) bright molecular line emission once the gas is dense enough to begin forming stars. Unless the IMF is anomalously skewed towards low-mass stars, the clusters should also show obvious signs of star formation via optical emission lines (e.g. H_alpha) after the stars have formed. These observational signatures should be readily observable towards any compact clus...

Longmore, Steven N

2015-01-01T23:59:59.000Z

146

INSIDE OUT AND UPSIDE DOWN: TRACING THE ASSEMBLY OF A SIMULATED DISK GALAXY USING MONO-AGE STELLAR POPULATIONS  

SciTech Connect (OSTI)

We analyze the present day structure and assembly history of a high-resolution hydrodynamic simulation of the formation of a Milky-Way-(MW)-like disk galaxy, from the ''Eris'' simulation suite, dissecting it into cohorts of stars formed at different epochs of cosmic history. At z = 0, stars with t{sub form} < 2 Gyr mainly occupy the stellar spheroid, with the oldest (earliest forming) stars having more centrally concentrated profiles. The younger age cohorts populate disks of progressively longer radial scale lengths and shorter vertical scale heights. At a given radius, the vertical density profiles and velocity dispersions of stars vary smoothly as a function of age, and the superposition of old, vertically extended and young, vertically compact cohorts gives rise to a double-exponential profile like that observed in the MW. Turning to formation history, we find that the trends of spatial structure and kinematics with stellar age are largely imprinted at birth, or immediately thereafter. Stars that form during the active merger phase at z > 3 are quickly scattered into rounded, kinematically hot configurations. The oldest disk cohorts form in structures that are radially compact and relatively thick, while subsequent cohorts form in progressively larger, thinner, colder configurations from gas with increasing levels of rotational support. The disk thus forms ''inside out'' in a radial sense and ''upside down'' in a vertical sense. Secular heating and radial migration influence the final state of each age cohort, but the changes they produce are small compared to the trends established at formation. The predicted correlations of stellar age with spatial and kinematic structure are in good qualitative agreement with the correlations observed for mono-abundance stellar populations in the MW.

Bird, Jonathan C.; Kazantzidis, Stelios; Weinberg, David H. [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Guedes, Javiera [Institute for Astronomy, ETH Zuerich, Wolgang-Pauli-Strasse 27, CH-8093 Zuerich (Switzerland); Callegari, Simone [Anthropology Institute and Museum, University of Zuerich, Winterthurerstrasse 190, CH-8057 Zuerich (Switzerland); Mayer, Lucio [Institute for Theoretical Physics, University of Zuerich, Winterthurerstrasse 190, CH-8057 Zuerich (Switzerland); Madau, Piero [Department of Astronomy and Astrophysics, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States)

2013-08-10T23:59:59.000Z

147

Steady state compact toroidal plasma production  

DOE Patents [OSTI]

Apparatus and method for maintaining steady state compact toroidal plasmas. A compact toroidal plasma is formed by a magnetized coaxial plasma gun and held in close proximity to the gun electrodes by applied magnetic fields or magnetic fields produced by image currents in conducting walls. Voltage supply means maintains a constant potential across the electrodes producing an increasing magnetic helicity which drives the plasma away from a minimum energy state. The plasma globally relaxes to a new minimum energy state, conserving helicity according to Taylor's relaxation hypothesis, and injecting net helicity into the core of the compact toroidal plasma. Controlling the voltage so as to inject net helicity at a predetermined rate based on dissipative processes maintains or increases the compact toroidal plasma in a time averaged steady state mode.

Turner, William C. (Livermore, CA)

1986-01-01T23:59:59.000Z

148

Belle Fourche River Compact (South Dakota)  

Broader source: Energy.gov [DOE]

The Belle Fourche River Compact, agreed to by South Dakota and Wyoming, seeks to provide for the most efficient use of the waters of the Belle Fourche River Basin for multiple purposes, and to...

149

NONEXISTENCE OF ARITHMETIC FAKE COMPACT HERMITIAN ...  

E-Print Network [OSTI]

? of G is a fake compact hermitian symmetric space, or a fake Xu, if its Betti ...... Letting A = (2?)16/4320 and using the bounds (13) and (22), we conclude that.

2011-06-17T23:59:59.000Z

150

Gravitational waves from merging compact binaries  

E-Print Network [OSTI]

Largely motivated by the development of highly sensitive gravitational-wave detectors, our understanding of merging compact binaries and the gravitational waves they generate has improved dramatically in recent years. ...

Hughes, Scott A.

151

Stuck-at-fault test set compaction  

E-Print Network [OSTI]

. Test set size under pattern score based dynamic compaction . . . 13 . . . 17 Figure 7. Pattern Score distribution v:ith pattern metric dynamic compaction. . . . . . . . . . . . . . I g LIST OF TABLES Page Table l. l. nuit Target Sclcction Methods.... Fault Target Selection Methods Random Minimum Detection Count Circuit Name c432 c499 c880 c1355 c1908 G2670 Excitation Balance 0. 136296 0. 191652 0. 170293 0. 173310 0. 187486 0. 190484 Pattern Count 1152 873 2693 1394 1708 5148...

Vanfickell, Jason Michael

2013-02-22T23:59:59.000Z

152

FABRICATION OF URANIUM OXYCARBIDE KERNELS AND COMPACTS FOR HTR FUEL  

SciTech Connect (OSTI)

As part of the program to demonstrate tristructural isotropic (TRISO)-coated fuel for the Next Generation Nuclear Plant (NGNP), Advanced Gas Reactor (AGR) fuel is being irradiation tested in the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL). This testing has led to improved kernel fabrication techniques, the formation of TRISO fuel particles, and upgrades to the overcoating, compaction, and heat treatment processes. Combined, these improvements provide a fuel manufacturing process that meets the stringent requirements associated with testing in the AGR experimentation program. Researchers at Idaho National Laboratory (INL) are working in conjunction with a team from Babcock and Wilcox (B&W) and Oak Ridge National Laboratory (ORNL) to (a) improve the quality of uranium oxycarbide (UCO) fuel kernels, (b) deposit TRISO layers to produce a fuel that meets or exceeds the standard developed by German researches in the 1980s, and (c) develop a process to overcoat TRISO particles with the same matrix material, but applies it with water using equipment previously and successfully employed in the pharmaceutical industry. A primary goal of this work is to simplify the process, making it more robust and repeatable while relying less on operator technique than prior overcoating efforts. A secondary goal is to improve first-pass yields to greater than 95% through the use of established technology and equipment. In the first test, called “AGR-1,” graphite compacts containing approximately 300,000 coated particles were irradiated from December 2006 to November 2009. The AGR-1 fuel was designed to closely replicate many of the properties of German TRISO-coated particles, thought to be important for good fuel performance. No release of gaseous fission product, indicative of particle coating failure, was detected in the nearly 3-year irradiation to a peak burn up of 19.6% at a time-average temperature of 1038–1121°C. Before fabricating AGR-2 fuel, each fabrication process was improved and changed. Changes to the kernel fabrication process included replacing the carbon black powder feed with a surface-modified carbon slurry and shortening the sintering schedule. AGR-2 TRISO particles were produced in a 6-inch diameter coater using a charge size about 21-times that of the 2-inch diameter coater used to coat AGR-1 particles. The compacting process was changed to increase matrix density and throughput by increasing the temperature and pressure of pressing and using a different type of press. AGR-2 fuel began irradiation in the ATR in late spring 2010.

Dr. Jeffrey A. Phillips; Eric L. Shaber; Scott G. Nagley

2012-10-01T23:59:59.000Z

153

Soil Quality Information Sheet Rangeland Soil Quality--Compaction  

E-Print Network [OSTI]

Soil Quality Information Sheet Rangeland Soil Quality--Compaction USDA, Natural Resources Conservation Service May 2001 Rangeland Sheet 4 What is compaction? Soil compaction occurs when moist or wet soil aggregates are pressed together and the pore space between them is reduced. Compaction changes

154

Compact Proof Certificates For Linear Logic Kaustuv Chaudhuri  

E-Print Network [OSTI]

Compact Proof Certificates For Linear Logic Kaustuv Chaudhuri INRIA, France http://kaustuv.chaudhuri

Chaudhuri, Kaustuv

155

Stellar Feedback in Dwarf Galaxy Formation  

E-Print Network [OSTI]

Dwarf galaxies pose significant challenges for cosmological models. In particular, current models predict a dark matter density that is divergent at the center, in sharp contrast with observations which indicate an approximately constant central density core. Energy feedback, from supernova explosions and stellar winds, has been proposed as a major factor shaping the evolution of dwarf galaxies. We present detailed cosmological simulations with sufficient resolution both to model the relevant physical processes and to directly assess the impact of stellar feedback on observable properties of dwarf galaxies. We show that feedback drives large-scale, bulk motion of the interstellar gas resulting in significant gravitational potential fluctuations and a consequent reduction in the central matter density, bringing the theoretical predictions in agreement with observations.

Sergey Mashchenko; James Wadsley; H. M. P. Couchman

2007-11-29T23:59:59.000Z

156

Disc formation from stellar tidal disruptions  

E-Print Network [OSTI]

The potential of tidal disruption of stars to probe otherwise quiescent supermassive black holes cannot be exploited, if their dynamics is not fully understood. So far, the observational appearance of these events has been commonly derived from analytical extrapolations of the debris dynamical properties just after the stellar disruption. In this paper, we perform hydrodynamical simulations of stars in highly eccentric orbits, that follow the stellar debris after disruption and investigate their ultimate fate. We demonstrate that gas debris circularize on an orbital timescale because relativistic apsidal precession causes the stream to self-cross. The higher the eccentricity and/or the deeper the encounter, the faster is the circularization. If the internal energy deposited by shocks during stream self-interaction is readily radiated, the gas forms a narrow ring at the circularization radius. It will then proceed to accrete viscously at a super-Eddington rate, puffing up under radiation pressure. If instead c...

Bonnerot, Clément; Lodato, Giuseppe; Price, Daniel J

2015-01-01T23:59:59.000Z

157

The Evolution of Stellar Exponential Discs  

E-Print Network [OSTI]

Models of disc galaxies which invoke viscosity-driven radial flows have long been known to provide a natural explanation for the origin of stellar exponential discs, under the assumption that the star formation and viscous timescales are comparable. We present models which invoke simultaneous star formation, viscous redistribution of gas and cosmologically-motivated gaseous infall and explore the predictions such models make for the scale length evolution and radial star formation history of galactic stellar discs. While the inclusion of viscous flows is essential for ensuring that the stellar disc is always exponential over a significant range in radius, we find that such flows play essentially no role in determining the evolution of the disc scale length. In models in which the main infall phase precedes the onset of star formation and viscous evolution, we find the exponential scale length to be rather invariant with time. On the other hand, models in which star formation/viscous evolution and infall occur concurrently result in a smoothly increasing scale length with time, reflecting the mean angular momentum of material which has fallen in at any given epoch. The disc stellar populations in these models are predominantly young (ie. ages < 5 Gyr) beyond a few scale lengths. In both cases, viscous flows are entirely responsible for transporting material to very large radii. We discuss existing observational constraints on these models from studies of both local and moderate redshift disc galaxies. In particular, a good agreement is found between the solar neighbourhood star formation history predicted by our infall model and the recent observational determination of this quantity by Rocha-Pinto et al (2000).

Annette Ferguson; Cathie Clarke

2001-03-14T23:59:59.000Z

158

The relativistic inverse stellar structure problem  

SciTech Connect (OSTI)

The observable macroscopic properties of relativistic stars (whose equations of state are known) can be predicted by solving the stellar structure equations that follow from Einstein’s equation. For neutron stars, however, our knowledge of the equation of state is poor, so the direct stellar structure problem can not be solved without modeling the highest density part of the equation of state in some way. This talk will describe recent work on developing a model independent approach to determining the high-density neutron-star equation of state by solving an inverse stellar structure problem. This method uses the fact that Einstein’s equation provides a deterministic relationship between the equation of state and the macroscopic observables of the stars which are composed of that material. This talk illustrates how this method will be able to determine the high-density part of the neutron-star equation of state with few percent accuracy when high quality measurements of the masses and radii of just two or three neutron stars become available. This talk will also show that this method can be used with measurements of other macroscopic observables, like the masses and tidal deformabilities, which can (in principle) be measured by gravitational wave observations of binary neutron-star mergers.

Lindblom, Lee [Theoretical Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States)

2014-01-14T23:59:59.000Z

159

Coherent change detection and interferometric ISAR measurements in the folded compact range  

SciTech Connect (OSTI)

A folded compact range configuration has been developed ant the Sandia National Laboratories` compact range antenna and radar-cross- section measurement facility as a means of performing indoor, environmentally-controlled, far-field simulations of synthetic aperture radar (SAR) measurements of distributed target samples (i.e. gravel, sand, etc.). The folded compact range configuration has previously been used to perform coherent-change-detection (CCD) measurements, which allow disturbances to distributed targets on the order of fractions of a wavelength to be detected. This report describes follow-on CCD measurements of other distributed target samples, and also investigates the sensitivity of the CCD measurement process to changes in the relative spatial location of the SAR sensor between observations of the target. Additionally, this report describes the theoretical and practical aspects of performing interferometric inverse-synthetic-aperture-radar (IFISAR) measurements in the folded compact range environment. IFISAR measurements provide resolution of the relative heights of targets with accuracies on the order of a wavelength. Several examples are given of digital height maps that have been generated from measurements performed at the folded compact range facility.

Sorensen, K.W.

1996-08-01T23:59:59.000Z

160

Upgrade of the neutral particle analyzers for the TJ-II stellarator  

SciTech Connect (OSTI)

The TJ-II stellarator, a magnetically confined plasma device, is equipped with a broad range of diagnostics for plasma characterization. These include 4 neutral particle analyzers (NPAs), consisting of two Acord-12's, to perform poloidal measurements, plus a compact NPA, and an Acord-24, these in tangential viewing positions. The Acord-12's were originally equipped with two rows of 6 channels each, one for hydrogen neutrals and the other for deuterium neutrals but were changed to a single row of 12 detectors for hydrogen, the principal working gas in TJ-II. With this upgrade the resultant improved energy resolution spectrum has allowed more reliable ion temperature estimates to be obtained. Here we present the upgrades undertaken and present results to demonstrate the improved performance of this diagnostic.

Fontdecaba, J. M., E-mail: josepmaria.fontdecaba@ciemat.es; Ros, A.; McCarthy, K. J. [Laboratorio Nacional de Fusión, CIEMAT, Madrid 28040 (Spain); Petrov, S. Ya.; Nesenevich, V. G.; Chernyshev, F. V. [Ioffe Physical-Technical Institute, Saint Petersburg 194024 (Russian Federation); Barcala, J. M. [Departamento de Electrónica, CIEMAT, Madrid 28040 (Spain)

2014-11-15T23:59:59.000Z

Note: This page contains sample records for the topic "national compact stellarator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

VLT/X-SHOOTER NEAR-INFRARED SPECTROSCOPY AND HST IMAGING OF GRAVITATIONALLY LENSED z ? 2 COMPACT QUIESCENT GALAXIES  

SciTech Connect (OSTI)

Quiescent massive galaxies at z ? 2 are thought to be the progenitors of present-day massive ellipticals. Observations revealed them to be extraordinarily compact. Until now, the determination of stellar ages, star formation rates, and dust properties via spectroscopic measurements has been feasible only for the most luminous and massive specimens (?3 × M*). Here we present a spectroscopic study of two near-infrared-selected galaxies that are close to the characteristic stellar mass M* (?0.9 × M* and ?1.3 × M*) and whose observed brightness has been boosted by the gravitational lensing effect. We measure the redshifts of the two galaxies to be z = 1.71 ± 0.02 and z = 2.15 ± 0.01. By fitting stellar population synthesis models to their spectrophotometric spectral energy distributions we determine their ages to be 2.4{sup +0.8}{sub -0.6} Gyr and 1.7 ± 0.3 Gyr, respectively, which implies that the two galaxies have higher mass-to-light ratios than most quiescent z ? 2 galaxies in other studies. We find no direct evidence for active star formation or active galactic nucleus activity in either of the two galaxies, based on the non-detection of emission lines. Based on the derived redshifts and stellar ages we estimate the formation redshifts to be z=4.3{sup +3.4}{sub -1.2} and z=4.3{sup +1.0}{sub -0.6}, respectively. We use the increased spatial resolution due to the gravitational lensing to derive constraints on the morphology. Fitting Sérsic profiles to the de-lensed images of the two galaxies confirms their compactness, with one of them being spheroid-like and the other providing the first confirmation of a passive lenticular galaxy at a spectroscopically derived redshift of z ? 2.

Geier, S.; Man, A. W. S.; Krühler, T.; Toft, S.; Fynbo, J. P. U. [Dark Cosmology Centre, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Richard, J. [Centre de Recherche Astronomique de Lyon, Université Lyon 1, 9 Avenue Charles Andre, F-69230 Saint Genis Laval (France); Marchesini, D., E-mail: sgeier@astro.ku.dk [Department of Physics and Astronomy, Tufts University, Medford, MA 06520 (United States)

2013-11-10T23:59:59.000Z

162

Phased array compaction cell for measurement of the transversely isotropic elastic properties of compacting sediments  

SciTech Connect (OSTI)

Sediments undergoing compaction typically exhibit transversely isotropic (TI) elastic properties. We present a new experimental apparatus, the phased array compaction cell, for measuring the TI elastic properties of clay-rich sediments during compaction. This apparatus uses matched sets of P- and S-wave ultrasonic transducers located along the sides of the sample and an ultrasonic P-wave phased array source, together with a miniature P-wave receiver on the top and bottom ends of the sample. The phased array measurements are used to form plane P-waves that provide estimates of the phase velocities over a range of angles. From these measurements, the five TI elastic constants can be recovered as the sediment is compacted, without the need for sample unloading, recoring, or reorienting. This paper provides descriptions of the apparatus, the data processing, and an application demonstrating recovery of the evolving TI properties of a compacting marine sediment sample.

Nihei, K.T.; Nakagawa, S.; Reverdy, F.; Meyer, L.R.; Duranti, L.; Ball, G.

2010-12-15T23:59:59.000Z

163

Strategy Guideline: Compact Air Distribution Systems  

SciTech Connect (OSTI)

This Strategy Guideline discusses the benefits and challenges of using a compact air distribution system to handle the reduced loads and reduced air volume needed to condition the space within an energy efficient home. Traditional systems sized by 'rule of thumb' (i.e., 1 ton of cooling per 400 ft2 of floor space) that 'wash' the exterior walls with conditioned air from floor registers cannot provide appropriate air mixing and moisture removal in low-load homes. A compact air distribution system locates the HVAC equipment centrally with shorter ducts run to interior walls, and ceiling supply outlets throw the air toward the exterior walls along the ceiling plane; alternatively, high sidewall supply outlets throw the air toward the exterior walls. Potential drawbacks include resistance from installing contractors or code officials who are unfamiliar with compact air distribution systems, as well as a lack of availability of low-cost high sidewall or ceiling supply outlets to meet the low air volumes with good throw characteristics. The decision criteria for a compact air distribution system must be determined early in the whole-house design process, considering both supply and return air design. However, careful installation of a compact air distribution system can result in lower material costs from smaller equipment, shorter duct runs, and fewer outlets; increased installation efficiencies, including ease of fitting the system into conditioned space; lower loads on a better balanced HVAC system, and overall improved energy efficiency of the home.

Burdick, A.

2013-06-01T23:59:59.000Z

164

EA-1437: Finding of No Significant Impact | Department of Energy  

Broader source: Energy.gov (indexed) [DOE]

No Significant Impact Proposed National Compact Stellarator Equipment Princeton Plasma Physics Laboratory, New Jersey The Department of Energy (DOE) has prepared an Environmental...

165

Report on the 1ST Meeting of the Joint Working Group on  

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

the experimental areas. Keith Rule accompanied us to visit the main fusion experimental devices including NSTX, TFTR test cell, neutron beam device, National Compact Stellarator...

166

Cylindrically Symmetric Models of Anisotropic Compact Stars  

E-Print Network [OSTI]

In this paper we have discussed the possibility of forming anisotropic compact stars from cosmological constant as one of the competent candidates of dark energy with cylindrical symmetry. For this purpose, we have applied the analytical solution of Krori and Barua metric to a particular cylindrically symmetric spacetime. The unknown constants in Krori and Barua metric have been determined by using masses and radii of class of compact stars like 4$U$1820-30, Her X-1, SAX J 1808-3658. The properties of these stars have been analyzed in detail. In this setting the cosmological constant has been taken as a variable which depends on the radial coordinates. We have checked all the regularity conditions, stability and surface redshift of the compact stars 4$U$1820-30, Her X-1, SAX J 1808-3658.

G. Abbas; Sumara Nazeer; M. A. Meraj

2014-12-16T23:59:59.000Z

167

Plasma-enhanced gasification of low-grade coals for compact power plants  

SciTech Connect (OSTI)

A high temperature of a steam torch ensures an efficient gasification of low-grade coals, which is comparable to that of high-grade coals. Therefore, the coal gasification system energized by microwaves can serve as a moderately sized power plant due to its compact and lightweight design. This plasma power plant of low-grade coals would be useful in rural or sparsely populated areas without access to a national power grid.

Uhm, Han S. [Department of Electrophysics, Kwangwoon University, 447-1 Wolgye-Dong, Nowon-Gu, Seoul 139-701 (Korea, Republic of); Hong, Yong C.; Shin, Dong H.; Lee, Bong J. [Convergence Plasma Research Center, National Fusion Research Institute, 113 Gwahangno, Yuseong-Gu, Daejeon 305-333 (Korea, Republic of)

2011-10-15T23:59:59.000Z

168

The Influence of Stellar Energetics and Dark Matter on the Chemical Evolution of Dwarf Irregulars  

E-Print Network [OSTI]

A chemical evolution model following the evolution of the abundances of H, He, C, N, O and Fe for dwarf irregular and blue compact galaxies is presented. This model takes into account detailed nucleosynthesis and computes in detail the rates of supernovae of type II and I. The star formation is assumed to have proceeded in short but intense bursts. The novelty relative to previous models is that the development of a galactic wind is studied in detail by taking into account the energy injected into the interstellar medium (ISM) from both supernovae and stellar winds from massive stars as well as the presence of dark matter halos. Both metal enriched and normal winds have been considered. Our main conclusions are: i) a substantial amount of dark matter (from 1 to 50 times larger than the luminous matter) is required in order to avoid the complete destruction of such galaxies during strong starbursts, and ii) the energy injected by stellar winds and type Ia supernovae into the ISM is negligible relative to the total thermal energy, and in particular to the type II supernovae, which in fact, dominate the energetics during starbursts.

F. Bradamante; F. Matteucci; A. D'Ercole

1998-01-14T23:59:59.000Z

169

Effects of the stellar wind on X-ray spectra of Cygnus X-3  

E-Print Network [OSTI]

We study X-ray spectra of Cyg X-3 from BeppoSAX, taking into account absorption and emission in the strong stellar wind of its companion. We find the intrinsic X-ray spectra are well modelled by disc blackbody emission, its upscattering by hot electrons with a hybrid distribution, and by Compton reflection. These spectra are strongly modified by absorption and reprocessing in the stellar wind, which we model using the photoionization code cloudy. The form of the observed spectra implies the wind is composed of two phases. A hot tenuous plasma containing most of the wind mass is required to account for the observed features of very strongly ionized Fe. Small dense cool clumps filling <0.01 of the volume are required to absorb the soft X-ray excess, which is emitted by the hot phase but not present in the data. The total mass-loss rate is found to be (0.6--1.6) x 10^-5 solar masses per year. We also discuss the feasibility of the continuum model dominated by Compton reflection, which we find to best describe our data. The intrinsic luminosities of our models suggest that the compact object is a black hole.

A. Szostek; A. A. Zdziarski

2008-02-04T23:59:59.000Z

170

Remote vacuum compaction of compressible hazardous waste  

DOE Patents [OSTI]

A system for remote vacuum compaction and containment of low-level radioactive or hazardous waste comprising a vacuum source, a sealable first flexible container, and a sealable outer flexible container for receiving one or more first flexible containers. A method for compacting low level radioactive or hazardous waste materials at the point of generation comprising the steps of sealing the waste in a first flexible container, sealing one or more first containers within an outer flexible container, breaching the integrity of the first containers, evacuating the air from the inner and outer containers, and sealing the outer container shut.

Coyne, Martin J. (Pittsburgh, PA); Fiscus, Gregory M. (McMurray, PA); Sammel, Alfred G. (Pittsburgh, PA)

1998-01-01T23:59:59.000Z

171

Remote vacuum compaction of compressible hazardous waste  

DOE Patents [OSTI]

A system is described for remote vacuum compaction and containment of low-level radioactive or hazardous waste comprising a vacuum source, a sealable first flexible container, and a sealable outer flexible container for receiving one or more first flexible containers. A method for compacting low level radioactive or hazardous waste materials at the point of generation comprising the steps of sealing the waste in a first flexible container, sealing one or more first containers within an outer flexible container, breaching the integrity of the first containers, evacuating the air from the inner and outer containers, and sealing the outer container shut. 8 figs.

Coyne, M.J.; Fiscus, G.M.; Sammel, A.G.

1998-10-06T23:59:59.000Z

172

Stellar Gas Flows Into A Dark Cluster Potential At The Galactic Center  

E-Print Network [OSTI]

The evidence for the presence of a concentration of dark matter at the Galactic center is now very compelling. There is no question that the stellar and gas kinematics within 0.01 pc is dominated by under-luminous matter in the form of either a massive black hole, a highly condensed distribution of stellar remnants, or a more exotic source of gravity. The unique, compact radio source Sgr A* appears to be coincident with the center of this region, but its size (less than 3x10^14 cm at lambda=1.35cm) is still significantly smaller than the current limiting volume enclosing this mass. Sgr A* may be the black hole, if the dark matter distribution is point-like. If not, we are left with a puzzle regarding its nature, and a question of why this source should be so unique and lie only at the Galactic center. Here, we examine an alternative to the black hole paradigm---that the gravitating matter is a condensed cluster of stellar remnants---and study the properties of the Galactic center wind flowing through this region. Some of this gas is trapped in the cluster potential, and we study in detail whether this hot, magnetized gas is in the proper physical state to produce Sgr A*'s spectrum. We find that at least for the Galactic center environment, the temperature of the trapped gas never attains the value required for significant GHz emission. In addition, continuum (mostly bremsstrahlung) emission at higher frequencies is below the current measurements and upper limits for this source. We conclude that the cluster potential is too shallow for the trapped Galactic center wind to account for Sgr A*'s spectrum, which instead appears to be produced only within an environment that has a steep-gradient potential like that generated by a black hole.

Fulvio Melia; Robert Coker

1998-06-14T23:59:59.000Z

173

Stellar Activity and Coronal Heating: an overview of recent results  

E-Print Network [OSTI]

Observations of the coronae of the Sun and of solar-like stars provide complementary information to advance our understanding of stellar magnetic activity, and of the processes leading to the heating of their outer atmospheres. While solar observations allow us to study the corona at high spatial and temporal resolution, the study of stellar coronae allows us to probe stellar activity over a wide range of ages and stellar parameters. Stellar studies therefore provide us with additional tools for understanding coronal heating processes, as well as the long-term evolution of solar X-ray activity. We discuss how recent studies of stellar magnetic fields and coronae contribute to our understanding of the phenomenon of activity and coronal heating in late-type stars.

Testa, Paola; Drake, Jeremy

2015-01-01T23:59:59.000Z

174

DETERMINATION OF STELLAR RADII FROM ASTEROSEISMIC DATA  

SciTech Connect (OSTI)

The NASA Kepler mission is designed to find planets through transits. Accurate and precise radii of the detected planets depend on knowing the radius of the host star accurately, which is difficult unless the temperature and luminosity of the star are known precisely. Kepler, however, has an asteroseismology program that will provide seismic variables that can characterize stellar radii easily, accurately, and extremely precisely. In this paper, we describe the Yale-Birmingham (YB) method to determine stellar radii using a combination of seismic and conventional variables and analyze the effect of these variables on the result. We find that for main-sequence stars, a knowledge of the parallax is not important to get accurate radii using the YB method: we can get results to an accuracy and precision of better than a few percent if we know the effective temperature and the seismic parameters for these stars. Metallicity does not make much difference either. However, good estimates of the effective temperature and metallicity, along with those of the seismic parameters, are essential to determine radii of subgiants properly. On the other hand, for red giants we find that determining radii properly is not possible without a good estimate of the parallax. We find that the so-called 'surface term' in the seismic data has minimal effect on the inferred radii. Uncertainties in the convective mixing length can matter under some circumstances and can cause a systematic shift in the inferred radii. Blind tests with data simulated to match those expected from the asteroseismic survey phase of Kepler show that it will be possible to infer stellar radii successfully using our method.

Basu, Sarbani [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States); Chaplin, William J.; Elsworth, Yvonne, E-mail: sarbani.basu@yale.ed, E-mail: w.j.chaplin@bham.ac.u, E-mail: y.p.elsworth@bham.ac.u [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom)

2010-02-20T23:59:59.000Z

175

Stellar Energy Solutions Inc | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data CenterFranconia, Virginia:FAQ < RAPID Jump to:Seadov Pty LtdSteen, Minnesota: Energy Resources Jump to: navigation, searchSteger,Stellar

176

Stellar science unveiled at space conference  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsrucLas ConchasPassiveSubmittedStatus TomAbout » Staff BasicSubcommittee onStatus of7Stellar science

177

Seoul National UniversitySeoul National University http://bp.snu.ac.kr1 The Effect of TiCl4-Treated TiO2  

E-Print Network [OSTI]

TiO2 Compact Layer on the Performance of Dye-Sensitized Solar Cell #12;Seoul National UniversitySeoul National University http://bp.snu.ac.kr Dye-Sensitized Solar Cell 2 Schematic Diagram of the Electron Flow by the TiO2 compact layer. Electrolyte Hydrolysis of TiCl4 Solution Dye-Coated TiO2 Back Electron Transfere

Park, Byungwoo

178

Frontiers in Planetary and Stellar Magnetism through High-Performance...  

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

Hwang, project co-PI Frontiers in Planetary and Stellar Magnetism through High-Performance Computing PI Name: Jonathan Aurnou PI Email: aurnou@ucla.edu Institution: University...

179

Neutrino Tomography of Gamma Ray Bursts and Massive Stellar Collapses  

E-Print Network [OSTI]

Neutrinos at energies above TeV can serve as probes of the stellar progenitor and jet dynamics of gamma ray bursts arising from stellar core collapses. They can also probe collapses which do not lead to gamma-rays, which may be much more numerous. We calculate detailed neutrino spectra from shock accelerated protons in jets just below the outer stellar envelope, before their emergence. We present neutrino flux estimates from such pre-burst jets for two different massive stellar progenitor models. These should be distinguishable by IceCube, and we discuss the implications.

Soebur Razzaque; Peter Meszaros; Eli Waxman

2003-10-14T23:59:59.000Z

180

Scientists use plasma shaping to control turbulence in stellarators...  

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

to control turbulence in stellarators By John Greenwald By John Greenwald October 21, 2014 Tweet Widget Google Plus One Share on Facebook Magnetic field strength in a...

Note: This page contains sample records for the topic "national compact stellarator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

THE EFFECTS OF STELLAR ROTATION. I. IMPACT ON THE IONIZING SPECTRA AND INTEGRATED PROPERTIES OF STELLAR POPULATIONS  

SciTech Connect (OSTI)

We present a sample of synthetic massive stellar populations created using the Starburst99 evolutionary synthesis code and new sets of stellar evolutionary tracks, including one set that adopts a detailed treatment of rotation. Using the outputs of the Starburst99 code, we compare the populations' integrated properties, including ionizing radiation fields, bolometric luminosities, and colors. With these comparisons we are able to probe the specific effects of rotation on the properties of a stellar population. We find that a population of rotating stars produces a much harder ionizing radiation field and a higher bolometric luminosity, changes that are primarily attributable to the effects of rotational mixing on the lifetimes, luminosities, effective temperatures, and mass-loss rates of massive stars. We consider the implications of the profound effects that rotation can have on a stellar population, and discuss the importance of refining stellar evolutionary models for future work in the study of extragalactic, and particularly high-redshift, stellar populations.

Levesque, Emily M. [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado 389-UCB, Boulder, CO 80309 (United States); Leitherer, Claus [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Ekstrom, Sylvia; Meynet, Georges; Schaerer, Daniel, E-mail: Emily.Levesque@colorado.edu [Geneva Observatory, University of Geneva, Maillettes 51, CH-1290 Sauverny (Switzerland)

2012-05-20T23:59:59.000Z

182

Compact range for variable-zone measurements  

DOE Patents [OSTI]

A compact range for testing antennas or radar targets includes a source for directing energy along a feedline toward a parabolic reflector. The reflected wave is a spherical wave with a radius dependent on the distance of the source from the focal point of the reflector.

Burnside, Walter D. (Columbus, OH); Rudduck, Roger C. (Columbus, OH); Yu, Jiunn S. (Albuquerque, NM)

1988-01-01T23:59:59.000Z

183

Compact Ultradense Objects in the Solar System  

E-Print Network [OSTI]

We describe properties and gravitational interactions of meteor-mass and greater compact ultra dense objects with nuclear density or greater (CUDO s). We discuss possible enclosure of CUDO s in comets, stability of these objects on impact with the Earth and Sun and show that the hypothesis of a CUDO core helps resolve issues challenging the understanding of a few selected cometary impacts.

J. Rafelski; Ch. Dietl; L. Labun

2013-03-19T23:59:59.000Z

184

A Global Compact to End Poverty  

E-Print Network [OSTI]

A Global Compact to End Poverty Jeffrey Sachs on stabilisation, transition and weapons of mass progress. We can realistically envision a world without extreme poverty by the year 2025 because. Sachs, The End of Poverty, 2005. WORLD ECONOMICS · Vol. 6 · No. 4 · October­December 2005 11 Jeffrey D

185

Spectrophotometric Resolution of Stellar Atmospheres with Microlensing  

E-Print Network [OSTI]

Microlensing is a powerful tool for studying stellar atmospheres because as the source crosses regions of formally infinite magnification (caustics) the surfaceof the star is resolved, thereby allowing one to measure the radial intensity profile, both photometrically and spectroscopically. However, caustic crossing events are relatively rare, and monitoring them requires intensive application of telescope resources. It is therefore essential that the observational parameters needed to accurately measure the intensity profile are quantified. We calculate the expected errors in the recovered radial intensity profile as a function of the unlensed flux, source radius, spatial resolution the recovered intensity profile, and caustic crossing time for the two principle types of caustics: point-mass and binary lenses. We demonstrate that for both cases there exist simple scaling relations between these parameters and the resultant errors. We find that the error as a function of the spatial resolution of the recovered profile, parameterized by the number of radial bins, increases as $N_R^{3/2}$, considerably faster than the naive $N_R^{1/2}$ expectation. Finally, we discuss the relative advantages of binary caustic-crossing events and point-lens events. Binary events are more common, easier to plan for, and provide more homogeneous information about the stellar atmosphere. However, a sub-class of point-mass events with low impact parameters can provide dramatically more information provided that they can be recognized in time to initiate observations.

B. Scott Gaudi; Andrew Gould

1998-02-14T23:59:59.000Z

186

THE LOCATIONS OF SHORT GAMMA-RAY BURSTS AS EVIDENCE FOR COMPACT OBJECT BINARY PROGENITORS  

SciTech Connect (OSTI)

We present a detailed investigation of Hubble Space Telescope rest-frame UV/optical observations of 22 short gamma-ray burst (GRB) host galaxies and sub-galactic environments. Utilizing the high angular resolution and depth of HST we characterize the host galaxy morphologies, measure precise projected physical and host-normalized offsets between the bursts and host centers, and calculate the locations of the bursts with respect to their host light distributions (rest-frame UV and optical). We calculate a median short GRB projected physical offset of 4.5 kpc, about 3.5 times larger than that for long GRBs, and find that ?25% of short GRBs have offsets of ?> 10 kpc. When compared to their host sizes, the median offset is 1.5 half-light radii (r{sub e} ), about 1.5 times larger than the values for long GRBs, core-collapse supernovae, and Type Ia supernovae. In addition, ?20% of short GRBs having offsets of ?> 5r{sub e} , and only ?25% are located within 1r{sub e} . We further find that short GRBs severely under-represent their hosts' rest-frame optical and UV light, with ?30%-45% of the bursts located in regions of their host galaxies that have no detectable stellar light, and ?55% in the regions with no UV light. Therefore, short GRBs do not occur in regions of star formation or even stellar mass. This demonstrates that the progenitor systems of short GRBs must migrate from their birth sites to their eventual explosion sites, a signature of kicks in compact object binary systems. Utilizing the full sample of offsets, we estimate natal kick velocities of ?20-140 km s{sup –1}. These independent lines of evidence provide the strongest support to date that short GRBs result from the merger of compact object binaries (NS-NS/NS-BH)

Fong, W.; Berger, E. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2013-10-10T23:59:59.000Z

187

Southeast Interstate Low-Level Radioactive Waste Management Compact (multi-state)  

Broader source: Energy.gov [DOE]

The Southeast Interstate Low-Level Radioactive Waste Management Compact is administered by the Compact Commission. The Compact provides for rotating responsibility for the region's low-level...

188

Engineering properties of miniature cement - fly ash compacts prepared by high pressure compaction  

E-Print Network [OSTI]

ENGINEERING PROPERTIES OF MINIATURE CEMENT - FLY ASH COMPACTS PREPARED BY HIGH PRESSURE COMPACTION E NGIRPR OT SFMMAFU AEU C-ALEYY HDOBPvvIi va vGI ge(iD(vI oannItI au NId(R E)L xrP1IeRPvT 9(evP(n uDnuPnnBIrv au vGI eI0DPeIBIrvR uae vGI i...IteII au LEHNFA -M Ho2FYoF EDtDRv 3456 L(7ae HDO7I8v? oP1Pn FrtPrIIePrt ENGINEERING PROPERTIES OF MINIATURE CEMENT - FLY ASH COMPACTS PREPARED BY HIGH PRESSURE COMPACTION E NGIRPR OT SFMMAFU AEU C-ALEYY E99ea1Ii (R va RvTnI (ri 8arvIrv OT? LP...

Bormann, Jeffrey Ray

1985-01-01T23:59:59.000Z

189

Fundamental building blocks for a compact optoelectronic neural network processor  

E-Print Network [OSTI]

The focus of this thesis is interconnects within the Compact Optoelectronic Neural Network Processor. The goal of the Compact Optoelectronic Neural Network Processor Project (CONNPP) is to build a small, rugged neural ...

Ruedlinger, Benjamin Franklin, 1976-

2003-01-01T23:59:59.000Z

190

December 2002 Issue #11 2002 IDENTIFYING AND MANAGING COMPACTION  

E-Print Network [OSTI]

of compaction The need to conduct field operations in a timely and efficient manner has given rise to concerns

Balser, Teri C.

191

A study of compaction methods for lunar soil simulants  

E-Print Network [OSTI]

, compaction by vibration, compaction under vacuum pressure under the simultaneous effect of vibration are examined. Duc to the increasing confining pressure, the air voids decrease and the particles will be more closely packed, thus increasing the relative... density. The research will be used to identify a convenient method for compacting samples for laboratory digging experiments. The results of the research conclude that compaction by using vacuum and vibration produce results which can be used to predict...

Ekkad, Rama Varadarajan

1993-01-01T23:59:59.000Z

192

Gas Feedback on Stellar Bar Evolution  

E-Print Network [OSTI]

We analyze evolution of live disk-halo systems in the presence of various gas fractions, f_gas less than 8% in the disk. We addressed the issue of angular momentum (J) transfer from the gas to the bar and its effect on the bar evolution. We find that the weakening of the bar, reported in the literature, is not related to the J-exchange with the gas, but is caused by the vertical buckling instability in the gas-poor disks and by a steep heating of a stellar velocity dispersion by the central mass concentration (CMC) in the gas-rich disks. The gas has a profound effect on the onset of the buckling -- larger f_gas brings it forth due to the more massive CMCs. The former process leads to the well-known formation of the peanut-shaped bulges, while the latter results in the formation of progressively more elliptical bulges, for larger f_gas. The subsequent (secular) evolution of the bar differs -- the gas-poor models exhibit a growing bar while gas-rich models show a declining bar whose vertical swelling is driven by a secular resonance heating. The border line between the gas-poor and -rich models lies at f_gas ~ 3% in our models, but is model-dependent and will be affected by additional processes, like star formation and feedback from stellar evolution. The overall effect of the gas on the evolution of the bar is not in a direct J transfer to the stars, but in the loss of J by the gas and its influx to the center that increases the CMC. The more massive CMC damps the vertical buckling instability and depopulates orbits responsible for the appearance of peanut-shaped bulges. The action of resonant and non-resonant processes in gas-poor and gas-rich disks leads to a converging evolution in the vertical extent of the bar and its stellar dispersion velocities, and to a diverging evolution in the bulge properties.

Ingo Berentzen; Isaac Shlosman; Inma Martinez-Valpuesta; Clayton Heller

2007-05-27T23:59:59.000Z

193

Stellar Burning Falk Herwig, Alexander Heger, and Frank  

E-Print Network [OSTI]

]. In these objects, a thermonuclear runaway of the helium shell on top of an electron-degenerate core (a young White implications for the production of neutron- rich elements. log Tlog Teffeff Figure 1-- A thermonuclear runaway stellar conditions. We will include a stellar equation of state as well as thermonuclear burning (TN burn

Herwig, Falk

194

3-DIMENSIONAL COMPACT DISC (CD) MICROFLUIDIC PLATFORM Presented to the  

E-Print Network [OSTI]

3-DIMENSIONAL COMPACT DISC (CD) MICROFLUIDIC PLATFORM _______________ A Thesis Presented OF THE THESIS 3-Dimensional Compact Disc (CD) Microfluidic Platform by Nitin Edmund Harwood Master of Science in a compact disc (CD) microfluidics platform involving two or more layers. The traditional 2-Dimensional

Kassegne, Samuel Kinde

195

THE COMPACT STEEP SPECTRUM AND GHZ PEAKED SPECTRUM RADIO SOURCES  

E-Print Network [OSTI]

THE COMPACT STEEP SPECTRUM AND GHZ PEAKED SPECTRUM RADIO SOURCES Christopher P. O'Dea Space@stsci.edu ABSTRACT I review the radio to X­ray properties of GHz Peaked Spectrum (GPS) and Compact Steep Spectrum The GHz Peaked Spectrum (GPS) and Compact Steep Spectrum (CSS) radio sources make up significant fractions

196

Thermonuclear inverse magnetic pumping power cycle for stellarator reactor  

DOE Patents [OSTI]

The plasma column in a stellarator is compressed and expanded alternatively in minor radius. First a plasma in thermal balance is compressed adiabatically. The volume of the compressed plasma is maintained until the plasma reaches a new thermal equilibrium. The plasma is then expanded to its original volume. As a result of the way a stellarator works, the plasma pressure during compression is less than the corresponding pressure during expansion. Therefore, negative work is done on the plasma over a complete cycle. This work manifests itself as a back-voltage in the toroidal field coils. Direct electrical energy is obtained from this voltage. Alternatively, after the compression step, the plasma can be expanded at constant pressure. The cycle can be made self-sustaining by operating a system of two stellarator reactors in tandem. Part of the energy derived from the expansion phase of a first stellarator reactor is used to compress the plasma in a second stellarator reactor.

Ho, Darwin D. (Pleasanton, CA); Kulsrud, Russell M. (Princeton, NJ)

1991-01-01T23:59:59.000Z

197

A Pure Geometric Approach to Stellar Structure  

E-Print Network [OSTI]

The present work represents a step to deal with stellar structure using a pure geometric approach. A geometric field theory is used to construct a model for a spherically symmetric configuration. The model obtained can be considered as a pure geometric one in the sense that the tensor describing the material distributions is not a phenomenological object, but a part of the geometric structure used. A general equation of state is obtained from, and not imposed on, the model. The solution obtained shows that there are different zones characterizing the configuration: a central radiation dominant zone, a probable convection zone as a physical interpretation of the singularity of the model and a corona like zone. The model may represent a type of main sequence stars. The present work shows that Einstein's geometerization scheme can be extended to gain more physical information within material distribution, with some advantages.

M. I. Wanas; Samah A. Ammar

2011-09-24T23:59:59.000Z

198

Asteroseismic Diagnostics of Stellar Convective Cores  

E-Print Network [OSTI]

We present a detailed study of the small frequency separations as diagnostics of the mass of the convective core and evolutionary stage of solar-type stars. We demonstrate how the small separations can be combined to provide sensitive tests for the presence of convective overshoot at the edge of the core. These studies are focused on low degree oscillation modes, the only modes expected to be detected in distant stars. Using simulated data with realistic errors, we find that the mass of the convective core can be estimated to within 5% if the total stellar mass is known. Systematic errors arising due to uncertainty in the mass could be up to 20%. The evolutionary stage of the star, determined in terms of the central hydrogen abundance using our proposed technique, however, is much less sensitive to the mass estimate.

Anwesh Mazumdar; Sarbani Basu; Braxton L. Collier; Pierre Demarque

2006-08-16T23:59:59.000Z

199

Thermally efficient compact fluorescent fixture systems  

SciTech Connect (OSTI)

Compact fluorescent lamps that can be inserted into conventional light fixtures are rapidly gaining acceptance as both a viable retrofit and new design approach to reducing lighting loads. Ideally, the compact fluorescent lamp should have the same light output as the incandescent lamp it replaces, but overheating inside typically small enclosed fixtures can reduce lumen output and hence lighting fixture efficiency by 15 to 20 percent. Fortunately, simple fixture modifications can erase this efficiency penalty, so that the full efficiency benefit of replacing incandescent lamps with fluorescent lamps can be realized. The paper describes such modifications and presents experimental data documenting the potential efficiency enhancement associated with thermal control systems. 4 refs., 7 figs.

Siminovitch, M.J.; Rubinstein, F.M.; Packer, M.

1991-04-01T23:59:59.000Z

200

Orthonormal bases of compactly supported wavelets  

E-Print Network [OSTI]

Abstract. Several variations are given on the construction of orthonormal bases of wavelets with compact support. They have, respectively, more symmetry, more regularity, or more vanishing moments for the scaling function than the examples constructed in Daubechies [Comm. Pure Appl. Math., 41 (1988), pp. 909-996]. Key words, wavelets, orthonormal bases, regularity, symmetry AMS(MOS) subject classifications. 26A16, 26A18, 26A27, 39B12

Ingrid Daubechies

1988-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "national compact stellarator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Compact x-ray source and panel  

DOE Patents [OSTI]

A compact, self-contained x-ray source, and a compact x-ray source panel having a plurality of such x-ray sources arranged in a preferably broad-area pixelized array. Each x-ray source includes an electron source for producing an electron beam, an x-ray conversion target, and a multilayer insulator separating the electron source and the x-ray conversion target from each other. The multi-layer insulator preferably has a cylindrical configuration with a plurality of alternating insulator and conductor layers surrounding an acceleration channel leading from the electron source to the x-ray conversion target. A power source is connected to each x-ray source of the array to produce an accelerating gradient between the electron source and x-ray conversion target in any one or more of the x-ray sources independent of other x-ray sources in the array, so as to accelerate an electron beam towards the x-ray conversion target. The multilayer insulator enables relatively short separation distances between the electron source and the x-ray conversion target so that a thin panel is possible for compactness. This is due to the ability of the plurality of alternating insulator and conductor layers of the multilayer insulators to resist surface flashover when sufficiently high acceleration energies necessary for x-ray generation are supplied by the power source to the x-ray sources.

Sampayon, Stephen E. (Manteca, CA)

2008-02-12T23:59:59.000Z

202

The Evolution of Compact Binary Star Systems  

E-Print Network [OSTI]

We review the formation and evolution of compact binary stars consisting of white dwarfs (WDs), neutron stars (NSs), and black holes (BHs). Mergings of compact binary stars are expected to be the most important sources for the forthcoming gravitational-wave (GW) astronomy. In the first part of the review, we discuss observational manifestations of close binary stars with NS and/or black components and their merger rate, crucial points in the formation and evolution of compact stars in binary systems, including the treatment of the natal kicks which NSs and BHs acquire during the core collapse of massive stars and the common envelope phase of binary evolution, which are most relevant to the merging rates of NS-NS, NS-BH and BH-BH binaries. The second part of the review is devoted mainly to formation and evolution of binary WDs and their observational manifestations, including their role as progenitors of cosmologically important thermonuclear SN Ia. We also consider AM CVn-stars which are thought to be the best verification binary GW sources for future low-frequency GW space interferometers.

Konstantin Postnov; Lev Yungelson

2014-03-21T23:59:59.000Z

203

A laboratory investigation of vibratory compaction of dry soils  

E-Print Network [OSTI]

. Standard Compaction Curve for Soil 3 (CL) 48 49 50 53 54 56 25 Effect of Frequency Variation on the Time Required to Achieve I/2 inch (12. 7 mm) of Settlement 57 26. Foot Size Effects on Compaction of Various Soils 59 27. Effect of Frequency... on the Compaction of Soil 1 (SP) Using Two Different Feet 63 28. Effect of Frequency on the Compaction of Soil 1 (SP) Using the Semi-Circular Foot with Various Static Weights 64 29. Effect of Frequency on the Compaction of Soil 1 (SP) Using the 5 Inch Diameter...

Webster, Cecil Ray

1984-01-01T23:59:59.000Z

204

RADIO AND MID-INFRARED PROPERTIES OF COMPACT STARBURSTS: DISTANCING THEMSELVES FROM THE MAIN SEQUENCE  

SciTech Connect (OSTI)

We investigate the relationship between 8.44 GHz brightness temperatures and 1.4 to 8.44 GHz radio spectral indices with 6.2 {mu}m polycyclic aromatic hydrocarbon (PAH) emission and 9.7 {mu}m silicate absorption features for a sample of 36 local luminous and ultraluminous infrared galaxies. We find that galaxies having small 6.2 {mu}m PAH equivalent widths (EQWs), which signal the presence of weak PAH emission and/or an excess of very hot dust, also have flat spectral indices. The three active galactic nuclei (AGN) identified through their excessively large 8.44 GHz brightness temperatures are also identified as AGN via their small 6.2 {mu}m PAH EQWs. We also find that the flattening of the radio spectrum increases with increasing silicate optical depth, 8.44 GHz brightness temperature, and decreasing size of the radio source even after removing potential AGN, supporting the idea that compact starbursts show spectral flattening as the result of increased free-free absorption. These correlations additionally suggest that the dust obscuration in these galaxies must largely be coming from the vicinity of the compact starburst itself, and is not distributed throughout the (foreground) disk of the galaxy. Finally, we investigate the location of these infrared-bright systems relative to the main sequence (star formation rate versus stellar mass) of star-forming galaxies in the local universe. We find that the radio spectral indices of galaxies flatten with increasing distance above the main sequence, or in other words, with increasing specific star formation rate. This indicates that galaxies located above the main sequence, having high specific star formation rates, are typically compact starbursts hosting deeply embedded star formation that becomes more optically thick in the radio and infrared with increased distance above the main sequence.

Murphy, E. J. [Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Stierwalt, S.; Armus, L. [Spitzer Science Center, California Institute of Technology, MC 314-6, Pasadena, CA 91125 (United States); Condon, J. J. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Evans, A. S., E-mail: emurphy@obs.carnegiescience.edu [Department of Astronomy, University of Virginia, 530 McCormick Road, Charlottesville, VA 22904 (United States)

2013-05-01T23:59:59.000Z

205

E-Print Network 3.0 - advanced stellar compass Sample Search...  

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

the first-ever simulations of non-ideal magnetohydrodynamical (MHD) stellar... a stellar wind (having different ejection mass rates) and a MHD ... Source: Casse, Fabien -...

206

The Dark Energy Survey: Prospects for Resolved Stellar Populations  

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

Wide angle and deep surveys, regardless of their primary purpose, always sample a large number of stars in the Galaxy and in its satellite system. We here make a forecast of the expected stellar sample resulting from the Dark Energy Survey and the perspectives that it will open for studies of Galactic structure and resolved stellar populations in general. An estimated 1.2 x 10{sup 8} stars will be sampled in DES grizY filters in the southern equatorial hemisphere. This roughly corresponds to 20% of all DES sources. Most of these stars belong to the stellar thick disk and halo of the Galaxy.

Rossetto, Bruno M [Rio de Janeiro Observ.; Santiago, Basilio X [Rio Grande do Sul U.; Rio de Janeiro Observ.; Girardi, Leo [Padua Observ.; Rio de Janeiro Observ.; Camargo, Julio I.B. [Rio de Janeiro Observ.; Balbinot, Eduardo [Rio Grande do Sul U.; Rio de Janeiro Observ.; da Costa, Luiz N [Rio de Janeiro Observ.; Yanny, Brian [Fermilab; Maia, Marcio A.G. [Rio de Janeiro Observ.; Makler, Martin [Rio de Janeiro, CBPF; Rio de Janeiro Observ.; Ogando, Ricardo L.C. [Rio de Janeiro Observ.; Pellegrini, Paulo S [Rio de Janeiro Observ.; Rio de Janeiro Observ.

2011-05-06T23:59:59.000Z

207

Stellar and dynamical evolution within triple systems  

E-Print Network [OSTI]

About 5-15% of stellar systems are at least triple. About 1% of systems with a primary of $\\tgs 1 \\Mscun$ are triple with a {\\it longer} peri od that is less than 30y, and so may in principle be capable of Roche-lobe overflow in both the inner and the outer orbits, at different times. We discuss possible evolutionary paths for these systems, some of which may lead to objects that are difficult to understand in the context of purely binary evolution. An example is OW Gem, a binary containing two supergiants (spectral types F and G) with masses that difffer by a factor of 1.5. There is also a triple-star pathway which could lead rather naturally to low-mass X-ray binaries; whereas binary pathways often appear rather contrived. We also discuss some dynamical pr ocesses involved in the 3-body problem. A number of triple stars are found in clusters. Similar systems can be created by gravitational capture during N-body simulations of Galactic clusters, especially if there is a n assumed primordial binary population. We discuss the properties of these triples , and note that many can be quite long-lived.

P. P. Eggleton; L. G. Kiseleva

1995-10-20T23:59:59.000Z

208

THE PROGENITOR MASS OF SN 2011dh FROM STELLAR POPULATION ANALYSIS  

SciTech Connect (OSTI)

Using Hubble Space Telescope photometry, we characterize the age of the stellar association in the vicinity of supernova (SN) 2011dh and use it to infer the zero-age main-sequence mass (M{sub ZAMS}) of the progenitor star. We find two distinct and significant star formation (SF) events with ages of <6 and 17{sup +3}{sub -4} Myr, and the corresponding M{sub ZAMS} are >29 and 13{sup +2}{sub -1} M{sub Sun }, respectively. These two bursts represent 18{sup +4}{sub -9}% (young) and 64{sup +10}{sub -14}% (old) of the total SF in the last 50 Myr. Adopting these fractions as probabilities suggests that the most probable M{sub ZAMS} is 13{sup +2}{sub -1} M{sub Sun }. These results are most sensitive to the luminosity function along the well-understood main sequence (MS) and are less sensitive to uncertain late-stage stellar evolution. Therefore, they stand even if the progenitor suffered disruptive post-MS evolution (e.g., eruptive mass loss or binary Roche-lobe overflow). Progenitor identification will help to further constrain the appropriate population. Even though pre-explosion images show a yellow supergiant (YSG) at the site of the SN, panchromatic SN light curves suggest a more compact star as the progenitor. In spite of this, our results suggest an association between the YSG and the SN. Not only was the star located at the SN site, but reinforcing an association, the star's bolometric luminosity is consistent with the final evolutionary stage of the 17 Myr old starburst. If the YSG disappears, then M{sub ZAMS} = 13{sup +2}{sub -1} M{sub Sun }, but if it persists, then our results allow the possibility that the progenitor was an unseen star of >29 M{sub Sun }.

Murphy, Jeremiah W.; Jennings, Zachary G.; Williams, Benjamin; Dalcanton, Julianne J. [Astronomy Department, University of Washington, Seattle, WA 98195 (United States); Dolphin, Andrew E., E-mail: jmurphy@astro.washington.edu, E-mail: adolphin@raytheon.com [Raytheon, 1151 E. Hermans Road, Tucson, AZ 85706 (United States)

2011-11-20T23:59:59.000Z

209

Raytheon's next generation compact inline cryocooler architecture  

SciTech Connect (OSTI)

Since the 1970s, Raytheon has developed, built, tested and integrated high performance cryocoolers. Our versatile designs for single and multi-stage cryocoolers provide reliable operation for temperatures from 10 to 200 Kelvin with power levels ranging from 50 W to nearly 600 W. These advanced cryocoolers incorporate clearance seals, flexure suspensions, hermetic housings and dynamic balancing to provide long service life and reliable operation in all relevant environments. Today, sensors face a multitude of cryocooler integration challenges such as exported disturbance, efficiency, scalability, maturity, and cost. As a result, cryocooler selection is application dependent, oftentimes requiring extensive trade studies to determine the most suitable architecture. To optimally meet the needs of next generation passive IR sensors, the Compact Inline Raytheon Stirling 1-Stage (CI-RS1), Compact Inline Raytheon Single Stage Pulse Tube (CI-RP1) and Compact Inline Raytheon Hybrid Stirling/Pulse Tube 2-Stage (CI-RSP2) cryocoolers are being developed to satisfy this suite of requirements. This lightweight, compact, efficient, low vibration cryocooler combines proven 1-stage (RS1 or RP1) and 2-stage (RSP2) cold-head architectures with an inventive set of warm-end mechanisms into a single cooler module, allowing the moving mechanisms for the compressor and the Stirling displacer to be consolidated onto a common axis and in a common working volume. The CI cryocooler is a significant departure from the current Stirling cryocoolers in which the compressor mechanisms are remote from the Stirling displacer mechanism. Placing all of the mechanisms in a single volume and on a single axis provides benefits in terms of package size (30% reduction), mass (30% reduction), thermodynamic efficiency (>20% improvement) and exported vibration performance (?25 mN peak in all three orthogonal axes at frequencies from 1 to 500 Hz). The main benefit of axial symmetry is that proven balancing techniques and hardware can be utilized to null all motion along the common axis. Low vibration translates to better sensor performance resulting in simpler, more direct mechanical mounting configurations, eliminating the need for convoluted, expensive, massive, long lead damping hardware.

Schaefer, B. R.; Bellis, L.; Ellis, M. J.; Conrad, T. [Raytheon Space and Airborne Systems, 2000 E. El Segundo Blvd., El Segundo, CA 90245 (United States)

2014-01-29T23:59:59.000Z

210

Compact Imaging Spectrometer Utilizing Immersed Gratings  

DOE Patents [OSTI]

A compact imaging spectrometer with an immersive diffraction grating that compensates optical distortions. The imaging spectrometer comprises an entrance slit for transmitting light, a system for receiving the light and directing the light, an immersion grating, and a detector array. The entrance slit, the system for receiving the light, the immersion grating, and the detector array are positioned wherein the entrance slit transmits light to the system for receiving the light and the system for receiving the light directs the light to the immersion grating and the immersion grating receives the light and directs the light through an optical element to the detector array.

Chrisp, Michael P. (Danville, CA); Lerner, Scott A. (Corvallis, OR); Kuzmenko, Paul J. (Livermore, CA); Bennett, Charles L. (Livermore, CA)

2006-03-21T23:59:59.000Z

211

Compact fluorescent lamp applications in luxury hotels  

SciTech Connect (OSTI)

Over the past several years, consumers, lighting designers, and energy conservationists have paid increasing attention to the special characteristics of compact fluorescent lamps (CFLs). CFLs can typically be used to replace incandescent lamps of three to four times their own wattage, and their color rendering indices (CRIs)-80 to 85-make them virtually indistinguishable from incandescents. The typical 10,0000-hour life of a CFL often makes savings in labor its most desirable feature when compared to a shorter-lived incandescent lamp.

Gilleskie, R.J.

1996-01-01T23:59:59.000Z

212

Compact Power Inc CPI | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home5b9fcbce19 NoPublic Utilities Address: 160Benin:EnergyWisconsin: Energy,(EC-LEDS)Columbus ElectricRefuseEnergyCompact Power Inc

213

Compact Absorption Chiller - Energy Innovation Portal  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation Proposed New SubstationCleanCommunity Involvement and Making aCompact soft x-ray

214

Development of a folded compact range and its application in performing coherent change detection and interferometric ISAR measurement  

SciTech Connect (OSTI)

A folded compact range configuration has been developed at the Sandia National Laboratories` compact range antenna and radar cross section measurement facility as a means of performing indoor, environmentally controlled far-field simulations of synthetic aperture radar (SAR) measurements of distributed target samples (i.e. gravel, sand, etc.). In particular, the folded compact range configuration has been used to perform both highly sensitive coherent change detection (CCD) measurements and interferometric inverse synthetic aperture radar (IFSAR) measurements, which, in addition to the two-dimensional spatial resolution afforded by typical interferometric SAR (ISAR) processing, provides resolution of the relative height of targets with accuracies on the order of a wavelength. This paper describes the development of the folded compact range, as well as the coherent change detection and interferometric measurements that have been made with the system. The measurement have been very successful, and have demonstrated not only the viability of the folded compact range concept in simulating SAR CCD and IFSAR measurements, but also its usefulness as a tool in the research and development of SAR CCD and IFSAR image generation and measurement methodologies.

Sorensen, K.W.; Zittel, D.H. [Sandia National Labs., Albuquerque, NM (United States); Littlejohn, J.H. [Geo-Centers, Inc., Albuquerque, NM (United States)

1996-09-01T23:59:59.000Z

215

Conservation potential of compact fluorescent lamps in India and Brazil  

SciTech Connect (OSTI)

We evaluate the conservation potential of compact fluorescent lamps (CFLs) for managing the rapidly increasing electrical energy and peak demand in India and Brazil. Using very conservative assumptions, we find that the cost of conserved energy using 16 W CFLs is 4 and 6 times less than the long range marginal cost of electricity for the two countries. The cost of avoided peak installed capacity is 6 and 9.5 times less than the cost of new installed capacity for India and Brazil. The analysis is undertaken from the three separate perspectives of the national economies, the consumers, and the utilities. We find that because residential electricity is subsidized, the consumers have little or no incentive to purchase and install the CFLs, unless they too are subsidized. However, the benefits of CFL installation to the utility are so large that subsidizing them is a paying proposition for the utility are so large that subsidizing them is a paying proposition for the utility in almost all cases. As an illustration of a gradual introduction strategy for CFLs, we calculate a scenario where national savings of the order of US $1.2 million per day for India and US $2.5 million per day for Brazil are reached in 10 years by a small and gradual transfer of subsidy from residential electricity to CFLs. We then explore the barriers to immediate large scale introduction of these lamps in the two countries. Specific technical and marketing problems are identified and discussed, which would require solution before such an introduction can be attempted. Lastly, we discuss the range of policy instruments, in addition to a subsidy scheme, that can be used for promoting the diffusion of these lamps in the domestic and commercial sector. 47 refs., 15 figs., 2 tabs.

Gadgil, A.; Martino Jannuzzi, G. de (Lawrence Berkeley Lab., CA (USA); Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia)

1989-07-01T23:59:59.000Z

216

Determination of the stellar (n,$\\gamma$) cross section of $^{54}Fe$ with accelerator mass spectrometry  

E-Print Network [OSTI]

Determination of the stellar (n,$\\gamma$) cross section of $^{54}Fe$ with accelerator mass spectrometry

Coquard, L; Dillmann, I; Wallner, A; Knie, K; Kutschera, W

2006-01-01T23:59:59.000Z

217

ROSAT Observations of Compact Groups of Galaxies  

E-Print Network [OSTI]

A search for X-ray emission from compact groups revealed detection from 8 out of the 12 HCG images extracted from the ROSAT public archive. For two of them the X-ray emission originates from galaxies in the group. On the contrary, three groups show an extended emission clearly caused by hot intracluster gas. A Raymond-Smith hot plasma model provides an excellent fit to the X-ray spectra. The estimated temperatures are distributed in a quite narrow range (from 0.73 to 0.92 keV) and are consistent, within the errors, with 0.9 keV. The luminosity ranging from 0.75 to $5.1\\cdot10^{42}$erg s$^{-1}$. The most relevant result is the low metal abundance surely detected in two of them and likely in a third that characterizes the hot gas cloud responsible for the X-ray emission. The data concerning the remaining 3 detected compact groups are not sufficient to discriminate with certainty between diffuse and/or point-like X-ray emission. However the results of the spectral analysis point to the presence of a hot gas again with low metal abundance.

P. Saracco; P. Ciliegi

1994-12-15T23:59:59.000Z

218

Compact wavefunctions from compressed imaginary time evolution  

E-Print Network [OSTI]

Simulation of quantum systems promises to deliver physical and chemical predictions for the frontiers of technology. Unfortunately, the exact representation of these systems is plagued by the exponential growth of dimension with the number of particles, or colloquially, the curse of dimensionality. The success of approximation methods has hinged on the relative simplicity of physical systems with respect to the exponentially complex worst case. Exploiting this relative simplicity has required detailed knowledge of the physical system under study. In this work, we introduce a general and efficient black box method for many-body quantum systems that utilizes technology from compressed sensing to find the most compact wavefunction possible without detailed knowledge of the system. It is a Multicomponent Adaptive Greedy Iterative Compression (MAGIC) scheme. No knowledge is assumed in the structure of the problem other than correct particle statistics. This method can be applied to many quantum systems such as spins, qubits, oscillators, or electronic systems. As an application, we use this technique to compute ground state electronic wavefunctions of hydrogen fluoride and recover 98% of the basis set correlation energy or equivalently 99.996% of the total energy with $50$ configurations out of a possible $10^7$. Building from this compactness, we introduce the idea of nuclear union configuration interaction for improving the description of reaction coordinates and use it to study the dissociation of hydrogen fluoride and the helium dimer.

Jarrod R. McClean; Alán Aspuru-Guzik

2014-09-25T23:59:59.000Z

219

Symmetry, Compact Closure and Dagger Compactness for Categories of Convex Operational Models  

E-Print Network [OSTI]

In the categorical approach to the foundations of quantum theory, one begins with a symmetric monoidal category, the objects of which represent physical systems, and the morphisms of which represent physical processes. Usually, this category is taken to be at least compact closed, and more often, dagger compact, enforcing a certain self-duality, whereby preparation processes (roughly, states) are inter-convertible with processes of registration (roughly, measurement outcomes). This is in contrast to the more concrete "operational" approach, in which the states and measurement outcomes associated with a physical system are represented in terms of what we here call a "convex operational model": a certain dual pair of ordered linear spaces -- generally, {\\em not} isomorphic to one another. On the other hand, state spaces for which there is such an isomorphism, which we term {\\em weakly self-dual}, play an important role in reconstructions of various quantum-information theoretic protocols, including teleportation and ensemble steering. In this paper, we characterize compact closure of symmetric monoidal categories of convex operational models in two ways: as a statement about the existence of teleportation protocols, and as the principle that every process allowed by that theory can be realized as an instance of a remote evaluation protocol --- hence, as a form of classical probabilistic conditioning. In a large class of cases, which includes both the classical and quantum cases, the relevant compact closed categories are degenerate, in the weak sense that every object is its own dual. We characterize the dagger-compactness of such a category (with respect to the natural adjoint) in terms of the existence, for each system, of a {\\em symmetric} bipartite state, the associated conditioning map of which is an isomorphism.

Howard Barnum; Ross Duncan; Alexander Wilce

2010-04-16T23:59:59.000Z

220

Compact Fluorescent Lighting in America: Lessons Learned on the Way to Market  

SciTech Connect (OSTI)

This report describes the history of compact fluorescent lamps (CFLs) in America. CFLs were introduced in the 1970s; however, it has taken more than 20 years for them to gain widespread recognition in the U.S. residential lighting market. This report reviews the development of CFLs, efforts to increase market acceptance of them, and barriers to that acceptance. Lessons to be learned from this study of CFLs are identified in hopes of assisting future market introduction efforts for other promising energy-efficient technologies. This report was prepared by the Pacific Northwest National Laboratory for the U.S. Department of Energy’s Office of Building Technologies, Emerging Technologies Program.

Sandahl, Linda J.; Gilbride, Theresa L.; Ledbetter, Marc R.; Steward, Heidi E.; Calwell, Chris

2006-05-22T23:59:59.000Z

Note: This page contains sample records for the topic "national compact stellarator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Old stellar populations in distant radio galaxies  

E-Print Network [OSTI]

I describe the current status of our attempts to determine the age of the oldest known stellar populations at high redshift, in the red mJy radio galaxies 53W091 ($z = 1.55$) and 53W069 ($z = 1.43$). During the past year the original conclusion of Dunlop et al. (1996) - that 53W091 is $>3$ Gyr old - has been questioned from two, basically orthogonal directions. First, reports that the near-infrared light from 53W091 is highly polarized have cast some doubt on whether its red colour is genuinely due to an old population of stars. Second, assuming that all the light is indeed due to stars, it has been claimed that 53W091 is in fact only 1-2 Gyr old. Here I present a preliminary analysis of new infrared polarimetric observations of 53W091 which show that the first of these criticisms can be rejected with very high confidence. I then explore why different modellers have derived different ages for 53W091, and present new model fits to the spectrum of 53W069 which demonstrate that different spectral synthesis codes are certainly in good agreement that this galaxy is 3-4 Gyr old. Finally I present a preliminary analysis of the morphologies and scale-lengths of 53W091 and 53W069 as derived from new I-band WFPC2 HST images, and compare the results with those for 3CR galaxies at comparable redshifts. I conclude that the scalelengths and luminosities of radio galaxies at $z \\simeq 1.5$ appear to scale together as would be predicted from the Kormendy relation for low-redshift elliptical galaxies.

James Dunlop

1998-01-13T23:59:59.000Z

222

Development, Test and Demonstration of a Cost-Effective, Compact...  

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

Development, Test and Demonstration of a Cost-Effective, Compact, Light-Weight, and Scalable High Temperature Inverter for HEVs, PHEVs, and FCVs Development, Test and Demonstration...

223

Western Interstate Nuclear Compact State Nuclear Policy (Multiple States)  

Broader source: Energy.gov [DOE]

Legislation authorizes states' entrance into the Western Interstate Nuclear Compact, which aims to undertake the cooperation of participating states in deriving the optimum benefit from nuclear and...

224

accreting compact stars: Topics by E-print Network  

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

of the millisecond brightness oscillations from low mass X-ray binaries during thermonuclear bursts can provide us with important information about compact star parameters....

225

Southwestern Low-Level Radioactive Waste Disposal Compact (South Dakota)  

Broader source: Energy.gov [DOE]

This legislation authorizes the state's entrance into the Southwestern Low-Level Radioactive Waste Disposal Compact, which provides for the cooperative management of low-level radioactive waste....

226

Appalachian States Low-Level Radioactive Waste Compact (Maryland)  

Broader source: Energy.gov [DOE]

This legislation authorizes Maryland's entrance into the Appalachian States Low-Level Radioactive Waste Compact, which seeks to promote interstate cooperation for the proper management and disposal...

227

Compact heat exchangers for condensation applications: Yesterday, today and tomorrow  

SciTech Connect (OSTI)

Compact heat exchangers are being increasingly considered for condensation applications in the process, cryogenic, aerospace, power and refrigeration industries. In this paper, different configurations available for condensation applications are analyzed and the current state-of-the-knowledge for the design of compact condensers is evaluated. The key technical issues for the design and development of compact heat exchangers for condensation applications are analyzed and major advantages are identified. The experimental data and performance prediction methods reported in the literature are analyzed to evaluate the present design capabilities for different compact heat-exchanger configurations. The design flexibility is evaluated for the development of new condensation applications, including integration with other process equipment.

Panchal, C.B.

1993-07-01T23:59:59.000Z

228

Cape Light Compact- Residential Energy Efficiency Rebate Program  

Broader source: Energy.gov [DOE]

Cape Light Compact (CLC) offers a variety of financial incentives to customers for purchasing energy efficient residential equipment. Residential customers can take advantage of incentives on...

229

Compact Optical Technique for Streak Camera Calibration  

SciTech Connect (OSTI)

The National Ignition Facility is under construction at the Lawrence Livermore National Laboratory for the U.S. Department of Energy Stockpile Stewardship Program. Optical streak cameras are an integral part of the experimental diagnostics instrumentation. To accurately reduce data from the streak cameras a temporal calibration is required. This article describes a technique for generating trains of precisely timed short-duration optical pulses that are suitable for temporal calibrations.

Curt Allen; Terence Davies; Frans Janson; Ronald Justin; Bruce Marshall; Oliver Sweningsen; Perry Bell; Roger Griffith; Karla Hagans; Richard Lerche

2004-04-01T23:59:59.000Z

230

Collective Deceleration: Toward a Compact Beam Dump  

SciTech Connect (OSTI)

With the increasing development of laser accelerators, the electron energy is already beyond GeV and even higher in near future. Conventional beam dump based on ionization or radiation loss mechanism is cumbersome and costly, also has radiological hazards. We revisit the stopping power of high-energy charged particles in matter and discuss the associated problem of beam dump from the point of view of collective deceleration. The collective stopping length in an ionized gas can be several orders of magnitude shorter than the Bethe-Bloch and multiple electromagnetic cascades stopping length in solid. At the mean time, the tenuous density of the gas makes the radioactivation negligible. Such a compact and non-radioactivating beam dump works well for short and dense bunches, which is typically generated from laser wakefield accelerator.

Wu, H.-C.; /Munich, Max Planck Inst. Quantenopt.; Tajima, T.; Habs, D.; /Munich, Max Planck Inst. Quantenopt. /Munich U.; Chao, A.W.; /SLAC; Meyer-ter-Vehn, J.; /Munich, Max Planck Inst. Quantenopt.

2011-11-28T23:59:59.000Z

231

Compact high voltage solid state switch  

DOE Patents [OSTI]

A compact, solid state, high voltage switch capable of high conduction current with a high rate of current risetime (high di/dt) that can be used to replace thyratrons in existing and new applications. The switch has multiple thyristors packaged in a single enclosure. Each thyristor has its own gate drive circuit that circuit obtains its energy from the energy that is being switched in the main circuit. The gate drives are triggered with a low voltage, low current pulse isolated by a small inexpensive transformer. The gate circuits can also be triggered with an optical signal, eliminating the trigger transformer altogether. This approach makes it easier to connect many thyristors in series to obtain the hold off voltages of greater than 80 kV.

Glidden, Steven C.

2003-09-23T23:59:59.000Z

232

Compact hydrogen/helium isotope mass spectrometer  

DOE Patents [OSTI]

The compact hydrogen and helium isotope mass spectrometer of the present invention combines low mass-resolution ion mass spectrometry and beam-foil interaction technology to unambiguously detect and quantify deuterium (D), tritium (T), hydrogen molecule (H.sub.2, HD, D.sub.2, HT, DT, and T.sub.2), .sup.3 He, and .sup.4 He concentrations and concentration variations. The spectrometer provides real-time, high sensitivity, and high accuracy measurements. Currently, no fieldable D or molecular speciation detectors exist. Furthermore, the present spectrometer has a significant advantage over traditional T detectors: no confusion of the measurements by other beta-emitters, and complete separation of atomic and molecular species of equivalent atomic mass (e.g., HD and .sup.3 He).

Funsten, Herbert O. (Los Alamos, NM); McComas, David J. (Los Alamos, NM); Scime, Earl E. (Morgantown, WV)

1996-01-01T23:59:59.000Z

233

Compact and highly efficient laser pump cavity  

DOE Patents [OSTI]

A new, compact, side-pumped laser pump cavity design which uses non-conventional optics for injection of laser-diode light into a laser pump chamber includes a plurality of elongated light concentration channels. In one embodiment, the light concentration channels are compound parabolic concentrators (CPC) which have very small exit apertures so that light will not escape from the pumping chamber and will be multiply reflected through the laser rod. This new design effectively traps the pump radiation inside the pump chamber that encloses the laser rod. It enables more uniform laser pumping and highly effective recycle of pump radiation, leading to significantly improved laser performance. This new design also effectively widens the acceptable radiation wavelength of the diodes, resulting in a more reliable laser performance with lower cost.

Chang, Jim J. (Dublin, CA); Bass, Isaac L. (Castro Valley, CA); Zapata, Luis E. (Livermore, CA)

1999-01-01T23:59:59.000Z

234

Compact imaging spectrometer utilizing immersed gratings  

DOE Patents [OSTI]

A compact imaging spectrometer with an immersive diffraction grating that compensates optical distortions. The imaging spectrometer comprises an entrance slit for transmitting light, means for receiving the light and directing the light, an immersion grating, and a detector array. The entrance slit, the means for receiving the light, the immersion grating, and the detector array are positioned wherein the entrance slit transmits light to the means for receiving the light and the means for receiving the light directs the light to the immersion grating and the immersion grating receives the light and directs the light to the means for receiving the light, and the means for receiving the light directs the light to the detector array.

Chrisp, Michael P. (Danville, CA); Lerner, Scott A. (Corvallis, OR); Kuzmenko, Paul J. (Livermore, CA); Bennett, Charles L. (Livermore, CA)

2007-07-03T23:59:59.000Z

235

Compact microwave ion source for industrial applications  

SciTech Connect (OSTI)

A 2.45 GHz microwave ion source for ion implanters has many good properties for industrial application, such as easy maintenance and long lifetime, and it should be compact for budget and space. But, it has a dc current supply for the solenoid and a rf generator for plasma generation. Usually, they are located on high voltage platform because they are electrically connected with beam extraction power supply. Using permanent magnet solenoid and multi-layer dc break, high voltage deck and high voltage isolation transformer can be eliminated, and the dose rate on targets can be controlled by pulse duty control with semiconductor high voltage switch. Because the beam optics does not change, beam transfer components, such as focusing elements and beam shutter, can be eliminated. It has shown the good performances in budget and space for industrial applications of ion beams.

Cho, Yong-Sub; Kim, Dae-Il; Kim, Han-Sung; Seol, Kyung-Tae; Kwon, Hyeok-Jung; Hong, In-Seok [Proton Engineering Frontier Project, Korea Atomic Energy Research Institute, Daejeon 305-353 (Korea, Republic of)

2012-02-15T23:59:59.000Z

236

Stirling Air Conditioner for Compact Cooling  

SciTech Connect (OSTI)

BEETIT Project: Infinia is developing a compact air conditioner that uses an unconventional high efficient Stirling cycle system (vs. conventional vapor compression systems) to produce cool air that is energy efficient and does not rely on polluting refrigerants. The Stirling cycle system is a type of air conditioning system that uses a motor with a piston to remove heat to the outside atmosphere using a gas refrigerant. To date, Stirling systems have been expensive and have not had the right kind of heat exchanger to help cool air efficiently. Infinia is using chip cooling technology from the computer industry to make improvements to the heat exchanger and improve system performance. Infinia’s air conditioner uses helium gas as refrigerant, an environmentally benign gas that does not react with other chemicals and does not burn. Infinia’s improvements to the Stirling cycle system will enable the cost-effective mass production of high-efficiency air conditioners that use no polluting refrigerants.

None

2010-09-01T23:59:59.000Z

237

Cooldown of the Compact Ignition Tokamak  

SciTech Connect (OSTI)

Cooldown of the Compact Ignition Tokamak (CIT) with the baseline liquid nitrogen cooling system was analyzed. On the basis of this analysis and present knowledge of the two-phase heat transfer, the current baseline CIT can be cooled down in about 1.5 h. An extensive heat transfer test program is recommended to reduce uncertainty in the heat transfer performance and to explore methods for minimizing the cooldown time. An alternate CIT cooldown system is described which uses a pressurized gaseous helium coolant in a closed-loop system. It is shown analytically that this system will cool down the CIT well within 1 h. Confidence in this analysis is sufficiently high that a heat transfer test program would not be necessary. The added cost of this alternate system is estimated to be about $5.3 million. This helium cooling system represents a reasonable backup approach to liquid nitrogen cooling of the CIT. 3 refs., 12 figs., 3 tabs.

Keeton, D.C.

1987-08-01T23:59:59.000Z

238

Compact conscious animal positron emission tomography scanner  

DOE Patents [OSTI]

A method of serially transferring annihilation information in a compact positron emission tomography (PET) scanner includes generating a time signal for an event, generating an address signal representing a detecting channel, generating a detector channel signal including the time and address signals, and generating a composite signal including the channel signal and similarly generated signals. The composite signal includes events from detectors in a block and is serially output. An apparatus that serially transfers annihilation information from a block includes time signal generators for detectors in a block and an address and channel signal generator. The PET scanner includes a ring tomograph that mounts onto a portion of an animal, which includes opposing block pairs. Each of the blocks in a block pair includes a scintillator layer, detection array, front-end array, and a serial encoder. The serial encoder includes time signal generators and an address signal and channel signal generator.

Schyler, David J. (Bellport, NY); O'Connor, Paul (Bellport, NY); Woody, Craig (Setauket, NY); Junnarkar, Sachin Shrirang (Sound Beach, NY); Radeka, Veljko (Bellport, NY); Vaska, Paul (Sound Beach, NY); Pratte, Jean-Francois (Stony Brook, NY); Volkow, Nora (Chevy Chase, MD)

2006-10-24T23:59:59.000Z

239

Oak Ridge National Laboratory National Security Programs  

E-Print Network [OSTI]

Oak Ridge National Laboratory National Security Programs Dr. Michael A. Kuliasha, Chief Scientist National Security Technologies Oak Ridge National Laboratory #12;2 OAK RIDGE NATIONAL LABORATORY U. S Security Challenges #12;3 OAK RIDGE NATIONAL LABORATORY U. S. DEPARTMENT OF ENERGY How Will Our Enemies

240

Symmetry, Compact Closure and Dagger Compactness for Categories of Convex Operational Models  

E-Print Network [OSTI]

In the categorical approach to the foundations of quantum theory, one begins with a symmetric monoidal category, the objects of which represent physical systems, and the morphisms of which represent physical processes. Usually, this category is taken to be at least compact closed, and more often, dagger compact, enforcing a certain self-duality, whereby preparation processes (roughly, states) are inter-convertible with processes of registration (roughly, measurement outcomes). This is in contrast to the more concrete "operational" approach, in which the states and measurement outcomes associated with a physical system are represented in terms of what we here call a "convex operational model": a certain dual pair of ordered linear spaces -- generally, {\\em not} isomorphic to one another. On the other hand, state spaces for which there is such an isomorphism, which we term {\\em weakly self-dual}, play an important role in reconstructions of various quantum-information theoretic protocols, including teleportatio...

Barnum, Howard; Wilce, Alexander

2010-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "national compact stellarator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Synonymous Address Compaction for Energy Reduction in Data TLB  

E-Print Network [OSTI]

Synonymous Address Compaction for Energy Reduction in Data TLB Chinnakrishnan S. Ballapuram chinnak and Computer Engineering College of Computing Georgia Institute of Technology, Atlanta, GA 30332 ABSTRACT-cycle compaction of address translation requests in order to save energy in the data TLB. Our results show

Lee, Hsien-Hsin "Sean"

242

GRI-04/0067 Evaluation of Soil Compaction  

E-Print Network [OSTI]

GRI-04/0067 Evaluation of Soil Compaction Measuring Devices FINAL REPORT Prepared by Distribution Title Soil Compaction Measuring Device Study Contractor GAS TECHNOLOGY INSTITUTE 1700 S. Mt. Prospect, KeySpan Energy, PECO Energy Company, Public Service Electric & Gas, Washington Gas, Environmental

243

Modelling the mechanical behaviour of pharmaceutical powders during compaction  

E-Print Network [OSTI]

are made of dry powder through a powder compaction process. In the pharmaceutical industry, billionsModelling the mechanical behaviour of pharmaceutical powders during compaction C.-Y. Wua,T, O.M. Ruddyb , A.C. Benthamb , B.C. Hancockc , S.M. Besta , J.A. Elliotta a Pfizer Institute for Pharmaceutical

Elliott, James

244

The Magellanic Bridge: The Nearest Purely Tidal Stellar Population  

E-Print Network [OSTI]

We report on observations of the stellar populations in twelve fields spanning the region between the Magellanic Clouds, made with the Mosaic-II camera on the 4-meter telescope at the Cerro-Tololo Inter-American Observatory. The two main goals of the observations are to characterize the young stellar population (which presumably formed in situ in the Bridge and therefore represents the nearest stellar population formed from tidal debris), and to search for an older stellar component (which would have been stripped from either Cloud as stars, by the same tidal forces which formed the gaseous Bridge). We determine the star-formation history of the young inter-Cloud population, which provides a constraint on the timing of the gravitational interaction which formed the Bridge. We do not detect an older stellar population belonging to the Bridge in any of our fields, implying that the material that was stripped from the Clouds to form the Magellanic Bridge was very nearly a pure gas.

Jason Harris

2006-12-04T23:59:59.000Z

245

Maximum stellar mass versus cluster membership number revisited  

E-Print Network [OSTI]

We have made a new compilation of observations of maximum stellar mass versus cluster membership number from the literature, which we analyse for consistency with the predictions of a simple random drawing hypothesis for stellar mass selection in clusters. Previously, Weidner and Kroupa have suggested that the maximum stellar mass is lower, in low mass clusters, than would be expected on the basis of random drawing, and have pointed out that this could have important implications for steepening the integrated initial mass function of the Galaxy (the IGIMF) at high masses. Our compilation demonstrates how the observed distribution in the plane of maximum stellar mass versus membership number is affected by the method of target selection; in particular, rather low n clusters with large maximum stellar masses are abundant in observational datasets that specifically seek clusters in the environs of high mass stars. Although we do not consider our compilation to be either complete or unbiased, we discuss the method by which such data should be statistically analysed. Our very provisional conclusion is that the data is not indicating any striking deviation from the expectations of random drawing.

Th. Maschberger; C. J. Clarke

2008-09-05T23:59:59.000Z

246

Modeling compaction-induced energy dissipation of granular HMX  

SciTech Connect (OSTI)

A thermodynamically consistent model is developed for the compaction of granular solids. The model is an extension of the single phase limit of two-phase continuum models used to describe Deflagration-to-Detonation Transition (DDT) experiments. The focus is on the energetics and dissipation of the compaction process. Changes in volume fraction are partitioned into reversible and irreversible components. Unlike conventional DDT models, the model is applicable from the quasi-static to dynamic compaction regimes for elastic, plastic, or brittle materials. When applied to the compaction of granular HMX (a brittle material), the model predicts results commensurate with experiments including stress relaxation, hysteresis, and energy dissipation. The model provides a suitable starting point for the development of thermal energy localization sub-scale models based on compaction-induced dissipation.

Gonthier, K.A. [Lamar Univ., Beaumont, TX (US). Dept. of Mechanical Engineering; Menikoff, R.; Son, S.F.; Asay, B.W. [Los Alamos National Lab., NM (US)

1998-12-31T23:59:59.000Z

247

The Size of Compact Extra Dimensions from Blackbody Radiation Laws  

E-Print Network [OSTI]

In this work we generalize the Stefan-Boltzmann and Wien's displacement laws for a $D$-dimensional manifold composed by 4 non-compact dimensions and $D-4$ compact dimensions, $ R^{1,3}$ x $T^{D-4} $. The electromagnetic field is assumed to pervade all compact and non-compact dimensions. In particular, the total radiated power becomes $ R(T) = \\sigma_B T^4 + \\sigma_D (a) \\, T^D $, where $a$ is the size of the compact extra dimensions. For $D=10$, predicted from String Theory, and $D=11$, from M-Theory, the outcomes agree with available experimental data for $a$ as high as 2 x $10^{-7}$m.

Ramaton Ramos; Henrique Boschi-Filho

2014-04-28T23:59:59.000Z

248

Perceptions of compact fluorescent lamps in the residential market  

SciTech Connect (OSTI)

Compact fluorescent lamps offer significant energy savings over other forms of residential lighting and last up to 10 times longer than conventional incandescent bulbs. In order to better understand existing barriers to acceptance and future opportunities for growth of compact fluorescent lighting in the residential retrofit sector, a three stage research project was designed and conducted by MACRO Consulting, Inc. Assessment of whether or not the benefits of compact fluorescent lamps are sufficient to overcome price resistance was one of the major purposes of this project. Residential customers were interviewed in focus group sessions to help determine key issues and motivating forces in the lighting/energy saving/cost saving equation. Residential customers in 5 major market areas were contacted by telephone, and data about their awareness, knowledge and use of compact fluorescent lighting were collected. These customers also participated in an attribute rating exercise in which compact fluorescent lamps were compared with fluorescent tubes and incandescent bulbs on a series of product attributes. A price elasticity exercise was also conducted. Teleconferences with retailers of compact fluorescent lamps were conducted in order to explore their knowledge of and attitudes towards compact fluorescent lamps. Customers agree that energy savings and longer life are both positive attributes for residential lighting products, but they are not yet ready to make the switch away from inexpensive, versatile and readily available incandescent bulbs to compact fluorescent lamps. Compact fluorescent lamps are rated poorly (even by satisfied'' users) on each of seven positive attributes of home lighting. Major barriers to increased use of compact fluorescent lamps include price, convenience, and performance. Prices above $10 are considered outrageous''. Product improvements are needed for appearance, light output and versatility.

Weiner, J.; Campbell, C.J. (Macro Consulting, Inc., Mountain View, CA (United States))

1992-07-01T23:59:59.000Z

249

Secular stability and instability in stellar systems surrounding massive objects  

E-Print Network [OSTI]

We examine the stability of a low-mass stellar system surrounding a massive central object. Examples of such systems include the centers of galaxies or star clusters containing a massive black hole, and the Oort comet cloud. If the self-gravity of the stellar system is the dominant non-Keplerian force, such systems may be subject to slowly growing (secular) lopsided instabilities. Stability to secular modes is largely determined by the dependence of the distribution function F on angular momentum J. If dF/dJ 0, as is expected if there is a loss cone at low angular momentum, all spherical systems in which F=0 at J=0 (an empty loss cone) are only neutrally stable, and flattened, non-rotating systems are generally unstable. These results suggest that secular instabilities may dominate the structure and evolution of the stellar systems in the centers of galaxies.

Scott Tremaine

2004-12-13T23:59:59.000Z

250

Structural Reliability: Assessing the Condition and Reliability of Casing in Compacting Reservoirs  

E-Print Network [OSTI]

. Effective stress may exceed rock compressive strength, inducing compaction. Wells in compacting reservoirs risk high failure and deformation rates. This project introduces the concept of structural reliability to quantify casing failure risks in compacting...

Chantose, Prasongsit

2012-02-14T23:59:59.000Z

251

Thermal and electrical conduction in the compaction direction of exfoliated graphite  

E-Print Network [OSTI]

Thermal and electrical conduction in the compaction direction of exfoliated graphite in the compaction direction of graphite-flake-based exfoliated graphite have been decoupled. The compact Exfoliated graphite is elongated graphite particles obtained by the exfoliation (typically involving rapid

Chung, Deborah D.L.

252

Star Formation and the Growth of Stellar Mass  

E-Print Network [OSTI]

Recent observations have demonstrated a significant growth in the integrated stellar mass of the red sequence since z=1, dominated by a steadily increasing number of galaxies with stellar masses M* 3x10^10 M_sun blue galaxies would also be overproduced; i.e., most of the new stars formed in blue cloud galaxies are in the massive galaxies. We explore a simple truncation scenario in which these `extra' blue galaxies have their star formation suppressed by an unspecified mechanism or mechanisms; simple cessation of star formation in these extra blue galaxies is approximately sufficient to build up the red sequence at M*<10^11 M_sun.

Eric F. Bell; Xian Zhong Zheng; Casey Papovich; Andrea Borch; Christian Wolf; Klaus Meisenheimer

2007-04-23T23:59:59.000Z

253

Particle acceleration at supernova shocks in young stellar clusters  

E-Print Network [OSTI]

We briefly discuss models of energetic particle acceleration by supernova shock in active starforming regions at different stages of their evolution. Strong shocks may strongly amplify magnetic fields due to cosmic ray driven instabilities. We discuss the magnetic field amplification emphasizing the role of the long-wavelength instabilities. Supernova shock propagating in the vicinity of a powerful stellar wind in a young stellar cluster is argued to increase the maximal CR energies at a given evolution stage of supernova remnant (SNR) and can convert a sizeable fraction of the kinetic energy release into energetic particles.

Bykov, A M; Osipov, S M

2011-01-01T23:59:59.000Z

254

Process for forming coal compacts and product thereof  

DOE Patents [OSTI]

A process for forming durable, mechanically strong compacts from coal particulates without use of a binder is disclosed. The process involves applying a compressive stress to a particulate feed comprising substantially water-saturated coal particles while the feed is heated to a final compaction temperature in excess of about 100.degree. C. The water present in the feed remains substantially in the liquid phase throughout the compact forming process. This is achieved by heating and compressing the particulate feed and cooling the formed compact at a pressure sufficient to prevent water present in the feed from boiling. The compacts produced by the process have a moisture content near their water saturation point. As a result, these compacts absorb little water and retain exceptional mechanical strength when immersed in high pressure water. The process can be used to form large, cylindrically-shaped compacts from coal particles (i.e., "coal logs") so that the coal can be transported in a hydraulic coal log pipeline.

Gunnink, Brett (Columbia, MO); Kanunar, Jayanth (Arlington, MA); Liang, Zhuoxiong (San Francisco, CA)

2002-01-01T23:59:59.000Z

255

COMPACTION OF FIBERBOARD IN A 9975 SHIPPING PACKAGE  

SciTech Connect (OSTI)

Compaction of lower layers in the fiberboard overpack has been observed in 9975 packages that contain elevated moisture. Lab testing has resulted in a better understanding of (1) the relationship between the fiberboard moisture level and compaction of the lower fiberboard assembly, and (2) the behavior of the fiberboard during transport. In laboratory tests, higher moisture content has been shown to correspond to higher total compaction of fiberboard material, greater rate of compaction, and continued compaction over a longer period of time. In addition, laboratory tests have shown that the application of a dynamic load results in higher fiberboard compaction. The test conditions and sample geometric/loading configurations were chosen to simulate the regulatory requirements for 9975 package input dynamic loading. Dynamic testing was conducted over a period of several months to acquire immediate and cumulative changes in geometric data for various moisture levels. Currently, one sample set has undergone a complete dynamic test regimen, while testing of another set is still in-progress. The dynamic input, data acquisition, test effects on sample dynamic parameters, and interim results from this test program will be summarized and compared to regulatory specifications for dynamic loading. This will provide a basis from which to evaluate the impact of moisture and fiberboard compaction on the safety basis for transportation (Safety Analysis Report for Packaging) and storage (facility Documented Safety Analysis) at the Savannah River Site (SRS).

Stefek, T.; Daugherty, W.; Estochen, E.; Leduc, D.

2011-05-11T23:59:59.000Z

256

Compact noninvasive electron bunch-length monitor  

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

A compact rf cavity was constructed that simultaneously resonates at many harmonic modes when excited by a repetitive bunched electron beam passing through its bore. The excitation of these modes provides a Fourier description of the temporal characteristics of the bunch train. The cavity was used to noninvasively characterize electron bunches produced from thin and thick GaAs photocathodes inside a DC high voltage photogun illuminated with 37 ps (full width half maximum, FWHM) laser pulses at repetition rates near 1500 MHz, at average beam current from 5 to 500????A , and at beam energy from 75 to 195 keV. The cavity bunch-length monitor could detect electron bunches as short as 57 ps (FWHM) when connected directly to a sampling oscilloscope, and could clearly distinguish bunches with varying degrees of space-charge induced growth and with different tail signatures. Efforts are under way to detect shorter bunches by designing cavities with increased bandwidth. This demonstration lends credibility to the idea that these cavities could also be used for other applications, including bunching and shaping, when driven with external rf.

Roberts, B.; Mammei, R. R.; Poelker, M.; McCarter, J. L.

2012-12-01T23:59:59.000Z

257

GUTs on Compact Type IIB Orientifolds  

SciTech Connect (OSTI)

We systematically analyze globally consistent SU(5) GUT models on intersecting D7-branes in genuine Calabi-Yau orientifolds with O3- and O7-planes. Beyond the well-known tadpole and K-theory cancellation conditions there exist a number of additional subtle but quite restrictive constraints. For the realization of SU(5) GUTs with gauge symmetry breaking via U(1)Y flux we present two classes of suitable Calabi-Yau manifolds defined via del Pezzo transitions of the elliptically fibred hypersurface P{sub 1,1,1,6,9}[18] and of the Quintic P{sub 1,1,1,1,1}[5], respectively. To define an orientifold projection we classify all involutions on del Pezzo surfaces. We work out the model building prospects of these geometries and present five globally consistent string GUT models in detail, including a 3-generation SU(5) model with no exotics whatsoever. We also realize other phenomenological features such as the 10 10 5{sub H} Yukawa coupling and comment on the possibility of moduli stabilization, where we find an entire new set of so-called swiss-cheese type Calabi-Yau manifolds. It is expected that both the general constrained structure and the concrete models lift to F-theory vacua on compact Calabi-Yau fourfolds.

Blumenhagen, Ralph; /Munich, Max Planck Inst.; Braun, Volker; /Dublin Inst.; Grimm, Thomas W.; /Bonn U.; Weigand, Timo; /SLAC

2008-12-01T23:59:59.000Z

258

The spheromak as a compact fusion reactor  

SciTech Connect (OSTI)

After summarizing the economic and utility-based rationale for compact, higher-power-density fusion reactors, the gun-sustained spheromak concept is explored as one of a number of poloidal-field-dominated confinement configurations that might improve the prospects for economically attractive and operationally simplified fusion power plants. Using a comprehensive physics/engineering/costing model for the spheromak, guided by realistic engineering constraints and physics extrapolation, a range of cost-optimized reactor design points is presented, and the sensitivity of cost to key physics, engineering, and operational variables is reported. The results presented herein provide the basis for conceptual engineering designs of key fusion-power-core (FPC) subsystems and more detailed plasma modeling of this promising, high mass-power-density concept, which stresses single-piece FPC maintenance, steady-state current drive through electrostatic magnetic helicity injection, a simplified co-axial electrode-divertor, and efficient resistive-coal equilibrium-field coils. The optimal FPC size and the cost estimates project a system that competes aggressively with the best offered by alternative energy sources while simplifying considerably the complexity that has generally been associated with most approaches to magnetic fusion energy.

Hagenson, R.L.; Krakowski, R.A.

1987-03-01T23:59:59.000Z

259

Color superconducting quark matter in compact stars  

E-Print Network [OSTI]

Recent indications for high neutron star masses (M \\sim 2 M_sun) and large radii (R > 12 km) could rule out soft equations of state and have provoked a debate whether the occurence of quark matter in compact stars can be excluded as well. We show that modern quantum field theoretical approaches to quark matter including color superconductivity and a vector meanfield allow a microscopic description of hybrid stars which fulfill the new, strong constraints. For these objects color superconductivity turns out to be an essential ingredient for a successful description of the cooling phenomenology in accordance with recently developed tests. We discuss the energy release in the neutrino untrapping transition as a new aspect of the problem that hybrid stars masquerade themselves as neutron stars. Quark matter searches in future generations of low-temperature/high-density nucleus-nucleus collision experiments such as low-energy RHIC and CBM @ FAIR might face the same problem of an almost crossover behavior of the deconfinement transition. Therefore, diagnostic tools shall be derived from effects of color superconductivity.

D. B. Blaschke; T. Klahn; F. Sandin

2007-12-02T23:59:59.000Z

260

MACHO (MAssive Compact Halo Objects) Data  

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

The primary aim of the MACHO Project is to test the hypothesis that a significant fraction of the dark matter in the halo of the Milky Way is made up of objects like brown dwarfs or planets: these objects have come to be known as MACHOs, for MAssive Compact Halo Objects. The signature of these objects is the occasional amplification of the light from extragalactic stars by the gravitational lens effect. The amplification can be large, but events are extremely rare: it is necessary to monitor photometrically several million stars for a period of years in order to obtain a useful detection rate. For this purpose MACHO has a two channel system that employs eight CCDs, mounted on the 50 inch telescope at Mt. Stromlo. The high data rate (several GBytes per night) is accommodated by custom electronics and on-line data reduction. The Project has taken more than 27,000 images with this system since June 1992. Analysis of a subset of these data has yielded databases containing light curves in two colors for 8 million stars in the LMC and 10 million in the bulge of the Milky Way. A search for microlensing has turned up four candidates toward the Large Magellanic Cloud and 45 toward the Galactic Bulge. The web page for data provides links to MACHO Project data portals and various specialized interfaces for viewing or searching the data. (Specialized Interface)

Note: This page contains sample records for the topic "national compact stellarator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

IONIZED OUTFLOWS FROM COMPACT STEEP SPECTRUM SOURCES  

SciTech Connect (OSTI)

Massive outflows are known to exist, in the form of extended emission-line regions (EELRs), around about one-third of powerful FR II radio sources. We investigate the origin of these EELRs by studying the emission-line regions around compact-steep-spectrum (CSS) radio galaxies that are younger (10{sup 3}-10{sup 5} yr old) versions of the FR II radio galaxies. We have searched for and analyzed the emission-line regions around 11 CSS sources by taking integral field spectra using Gemini Multi-Object Spectrograph on Gemini North. We fit the [O III] {lambda}5007 line and present the velocity maps for each detected emission-line region. We find, in most cases, that the emission-line regions have multi-component velocity structures with different velocity dispersions and/or flux distributions for each component. The velocity gradients of the emission-line gas are mostly well aligned with the radio axis, suggesting a direct causal link between the outflowing gas and the radio jets. The complex velocity structure may be a result of different driving mechanisms related to the onset of the radio jets. We also present the results from the line-ratio diagnostics we used to analyze the ionization mechanism of the extended gas, which supports the scenario where the emission-line regions are ionized by a combination of active galactic nucleus radiation and shock excitation.

Shih, Hsin-Yi; Stockton, Alan; Kewley, Lisa, E-mail: hsshih@ifa.hawaii.edu, E-mail: stockton@ifa.hawaii.edu, E-mail: lisa.kewley@anu.edu.au [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)

2013-08-01T23:59:59.000Z

262

E-Print Network 3.0 - alamos spheromak compact Sample Search...  

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

conditions. The simplicity and compact size of spheromaks provide excellent access for diagnostics... , injection of accelerated spheromak compact tori ... Source: Lawrence...

263

A Catalog of Ultra-compact High Velocity Clouds from the ALFALFA Survey: Local Group Galaxy Candidates?  

E-Print Network [OSTI]

We present a catalog of 59 ultra-compact high velocity clouds (UCHVCs) extracted from the 40% complete ALFALFA HI-line survey. The ALFALFA UCHVCs have median flux densities of 1.34 Jy km/s, median angular diameters of 10', and median velocity widths of 23 km/s. We show that the full UCHVC population cannot easily be associated with known populations of high velocity clouds. Of the 59 clouds presented here, only 11 are also present in the compact cloud catalog extracted from the commensal GALFA-HI survey, demonstrating the utility of this separate dataset and analysis. Based on their sky distribution and observed properties, we infer that the ALFALFA UCHVCs are consistent with the hypothesis that they may be very low mass galaxies within the Local Volume. In that case, most of their baryons would be in the form of gas, and because of their low stellar content, they remain unidentified by extant optical surveys. At distances of ~1 Mpc, the UCHVCs have neutral hydrogen (HI) masses of ~10^5 -10^6 M_sun, HI diamet...

Adams, Elizabeth A K; Haynes, Martha P

2013-01-01T23:59:59.000Z

264

Iron-carbon compacts and process for making them  

DOE Patents [OSTI]

The present invention includes iron-carbon compacts and a process for making them. The process includes preparing a slurry comprising iron powder, furfuryl alcohol, and a polymerization catalyst for initiating the polymerization of the furfuryl alcohol into a resin, and heating the slurry to convert the alcohol into the resin. The resulting mixture is pressed into a green body and heated to form the iron-carbon compact. The compact can be used as, or machined into, a magnetic flux concentrator for an induction heating apparatus.

Sheinberg, Haskell (Santa Fe, NM)

2000-01-01T23:59:59.000Z

265

Compaction of wood chips - physical and pulping characteristics  

SciTech Connect (OSTI)

The temperatures of the uncompacted chips of Pinus taeda were, in general, higher than those of compacted chips when stored outdoors in containers for 236 days. The results of the study after storage indicated that the moisture content (MC) of compacted chips is the same as that of green chips, the uncompacted equivalent mass of chips exhibits a substantial loss in MC, and there is approximately 18% increase in MC of the uncompacted chips simulating a stockpile when compared with MC of green chips. The compaction process neither damaged wood fibers nor altered the chip response to conventional pulping.

Hassan, A.E.; Reeves, R.H.

1980-01-01T23:59:59.000Z

266

Compact Stars in low-mass X-ray binaries  

E-Print Network [OSTI]

We propose a model for compact stars in low-mass X-ray binaries(LMXBs) namely KS 1731-260, EXO 1745-248 and 4U 1608-52. Here we investigate the physical phenomena of a compact star in the LMXBs. Using our model, we have calculated central density, surface density, mass(M) and red-shift for the above mentioned compact stars, which is very much consistent with the reported data. We also obtain the possible equation of state(EOS) of the stars which is physically acceptable.

Sk. Monowar Hossein; Sajahan Molla; Md. Abdul Kayum Jafry; Mehedi Kalam

2014-08-13T23:59:59.000Z

267

Limit to the radio emission from a putative central compact source in SN1993J  

E-Print Network [OSTI]

SN1993J in M81 is the best studied young radio-luminous supernova in the Northern Hemisphere. We recently reported results from the analysis of a complete set of VLBI observations of this supernova at 1.7, 2.3, 5.0, and 8.4 GHz, covering a time baseline of more than one decade. Those reported results were focused on the kinematics of the expanding shock, the particulars of its evolving non-thermal emission, the density profile of the circumstellar medium, and the evolving free-free opacity by the supernova ejecta. In the present paper, we complete our analysis by performing a search for any possible signal from a compact source (i.e., a stellar-mass black hole or a young pulsar nebula) at the center of the expanding shell. We have performed a stacking of all our VLBI images at each frequency, after subtraction of our best-fit shell model at each epoch, and measured the peak intensity in the stacked residual image. Given the large amount of available global VLBI observations, the stacking of all the residual i...

Marti-Vidal, I

2013-01-01T23:59:59.000Z

268

ASTR 498N Spring 2014 Special Problems in Astronomy: Stellar Evolution  

E-Print Network [OSTI]

& The Virial Theorem Feb 4 Thermonuclear Fusion & Stellar Life Cycles 6 The H-R Diagram & Stellar Clusters 11; The Cooling of White Dwarfs Mar 4 *** First Mid-Term Exam *** 6 Thermonuclear Fusion in Stars Chapt 4 11

Harrington, J. Patrick

269

AN ASTROMETRIC SEARCH FOR A STELLAR COM COMPANION TO THE SUN  

E-Print Network [OSTI]

come- tary impacts and the Sun's motion perpendicular to theA STELLAR COMPANION TO THE SUN S. Perlmutter (PhD. Thesis)for a Stellar Companion to the Sun Saul Perlmutter Lawrence

Perlmutter, S.

2008-01-01T23:59:59.000Z

270

National Laboratory Impact Initiative  

Broader source: Energy.gov [DOE]

The National Laboratory Impact Initiative supports the relationship between the Office of Energy Efficiency & Renewable Energy and the national laboratory enterprise.  The national laboratories...

271

arXiv:astroph/0208546 Flare Heating in Stellar Coronae  

E-Print Network [OSTI]

J. Drake Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 vkashyap@astro.phys.ethz.ch ABSTRACT An open question in the #12;eld of solar and stellar astrophysics is the source of heating, but are more numerous. Previous analyses of ares in light-curves of active stars have shown that this index

Guedel, Manuel

272

Modelling of Stellar Atmospheres IAU Symposium, Vol. xxx, xxxx  

E-Print Network [OSTI]

Abstract. We discuss the dynamics in the outer atmospheres of AGB giants. 1. Motivation Hinkle et al. (1982 with an excitation temperature of about 800-1000 K and an almost zero velocity relative to the stellar systemic molecular envelope", should be common not only in Miras but in evolved red giants in general. 2. Project

273

Design studies of low aspect ratio quasi-omnigenous stellarators  

E-Print Network [OSTI]

optimization principles for the design of a more attractive reactor. These are 3 and 4 field period low aspect ratio quasi-omnigenous stellarators based on an optimization method that aims at improved confinement stability boundaries. 1. Configuration optimization The development of increasingly sophisticated

Martín-Solís, José Ramón

274

Computer Models in Astronomy and Statistics Stellar Evolution  

E-Print Network [OSTI]

Computer Models in Astronomy and Statistics Stellar Evolution Calibration of X-ray Detectors Embedding Astronomical Computer Models into Complex Statistical Models David A. van Dyk Statistics Section Dyk Complex Analyses with Computer Models in Astronomy #12;Computer Models in Astronomy and Statistics

van Dyk, David

275

Computer Models in Astronomy and Statistics Stellar Evolution  

E-Print Network [OSTI]

Computer Models in Astronomy and Statistics Stellar Evolution Calibration of X-ray Detectors Embedding Astronomical Computer Models into Complex Statistical Models David A. van Dyk Statistics Section, Imperial College London UCLA, February 2012 David A. van Dyk Complex Analyses with Computer Models

van Dyk, David

276

ISO impact on stellar models and vice versa  

E-Print Network [OSTI]

We present a detailed spectroscopic study of a sample of bright, mostly cool, stars observed with the Short-Wavelength Spectrometer (SWS) on board the Infrared Space Observatory (ISO), which enables the accurate determination of the stellar parameters of the cool giants, but also serves as a critical review of the ISO-SWS calibration.

L. Decin; C. Waelkens; K. Eriksson; B. Gustafsson; B. Plez; A. J. Sauval; W. Van Assche; B. Vandenbussche

2000-08-23T23:59:59.000Z

277

OPTIMIZATION OF STELLARATOR REACTOR PARAMETERS J. F. Lyon1  

E-Print Network [OSTI]

OPTIMIZATION OF STELLARATOR REACTOR PARAMETERS J. F. Lyon1 , L.P. Ku2 , P. Garabedian3 , L. El-average) approach for optimizing the main reactor parameters allows study of the relationship between global developed to optimize the main reactor parameters (, the average magnetic field on axis , etc

278

Grids of Stellar Models and Frequencies with CLES + LOSC  

E-Print Network [OSTI]

We present a grid of stellar models, obtained with the CLES evolution code, following the specification of ESTA-Task1, and the corresponfing seismic properties, computed with the LOSC code. We provide a complete description of the corresponding files that will be available on the ESTA web-pages.

J. Montalban; A. Miglio; A. Noels; R. Scuflaire

2008-02-22T23:59:59.000Z

279

Cirrus Microphysical Properties from Stellar Aureole Measurements, Phase I  

SciTech Connect (OSTI)

While knowledge of the impact of aerosols on climate change has improved significantly due to the routine, ground-based, sun photometer measurements of aerosols made at AERONET sites world-wide, the impact of cirrus clouds remains much less certain because they occur high in the atmosphere and are more difficult to measure. This report documents work performed on a Phase I SBIR project to retrieve microphysical properties of cirrus ice crystals from stellar aureole imagery. The Phase I work demonstrates that (1) we have clearly measured stellar aureole profiles; (2) we can follow the aureole profiles out to ~1/4 degree from stars (~1/2 degree from Jupiter); (3) the stellar aureoles from cirrus have very distinctive profiles, being flat out to a critical angle, followed by a steep power-law decline with a slope of ~-3; (4) the profiles are well modeled using exponential size distributions; and (5) the critical angle in the profiles is ~0.12 degrees, (6) indicating that the corresponding critical size ranges from ~150 to ~200 microns. The stage has been set for a Phase II project (1) to proceed to validating the use of stellar aureole measurements for retrieving cirrus particle size distributions using comparisons with optical property retrievals from other, ground-based instruments and (2) to develop an instrument for the routine, automatic measurement of thin cirrus microphysical properties.

DeVore, J.G.; Kristl, J.A.; Rappaport, S.A

2012-04-20T23:59:59.000Z

280

Paper No. PIIB.6 THE 13TH INTERNATIONAL STELLARATOR WORKSHOP  

E-Print Network [OSTI]

Laboratory, The Australian National University, Canberra, ACT 0200, Australia (4) Centre de Recherche en

Redi, Martha H.

Note: This page contains sample records for the topic "national compact stellarator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

National System Templates: Building Sustainable National Inventory...  

Open Energy Info (EERE)

Templates: Building Sustainable National Inventory Management Systems Jump to: navigation, search Tool Summary LAUNCH TOOL Name: National System Templates: Building Sustainable...

282

Stellar models with the ML2 theory of convection  

E-Print Network [OSTI]

The mixing length theory (MLT) used to compute the temperature gradient in superadiabatic layers of stellar (interior and atmosphere) models contains in its standard form 4 free parameters. Three parameters are fixed a priori (and define what we denote as the MLT 'flavour') whereas one (the so-called mixing length) is calibrated by reproducing observational constraints. The 'classical' B\\"ohm-Vitense flavour is used in all modern MLT-based stellar model computations and, despite its crude approximations, the resulting $T_{eff}$ scale appears -- perhaps surprisingly -- remarkably realistic, once the mixing length parameter is calibrated with a solar model. Model atmosphere computations employ parameter choices different from what is used in stellar interior modelling, raising the question of whether a single MLT flavour and mixing length value can be used to compute interiors and atmospheres of stars of all types. As a first step towards addressing this issue, we study whether the MLT flavour (the so-called ML2) and mixing length choice that have been proven adequate to model white dwarf atmospheres, is able to provide, when used in stellar models, results at least comparable to the use of the 'classical' B\\"ohm-Vitense flavour. We have computed solar models and evolutionary tracks for both low- and intermediate-mass Population I and II stars, adopting both solar calibrated B\\"ohm-Vitense and ML2 flavours of the MLT in our stellar evolution code, and state-of-the-art input physics. The two sets of models provide consistent results, with only minor differences. Both calibrations reproduce also the $T_{eff}$ of red giants in a sample of Galactic globular clusters.

M. Salaris; S. Cassisi

2008-07-05T23:59:59.000Z

283

Codings of separable compact subsets of the first Baire class  

E-Print Network [OSTI]

Let $X$ be a Polish space and $K$ a separable compact subset of the first Baire class on $X$. For every sequence $\\bs$ dense in $\\kk$, the descriptive set-theoretic properties of the set \\[ \\lbf=\\{L\\in[\

Dodos, Pandelis

2008-01-01T23:59:59.000Z

284

A thermodynamic approach for compaction of asphaltic composites  

E-Print Network [OSTI]

results. Modeling asphalt concrete compaction, and also the ability to thereby predict response of mixes, is of great importance to the pavement industry. Asphalt concrete exhibits nonlinear response even at small strains and the response of asphalt...

Koneru, Saradhi

2009-05-15T23:59:59.000Z

285

COMPACTNESS OF COMPOSITION OPERATORS ON BMOA Wayne Smith  

E-Print Network [OSTI]

COMPACTNESS OF COMPOSITION OPERATORS ON BMOA Wayne Smith Abstract. A function theoretic;2 WAYNE SMITH for all functions in the unit ball of BMOA; see Theorem 3.1 in [BCM]. M. Tjani [Tj, Theorem

Smith, Wayne

286

Compact Data Structures with Fast Queries Daniel K. Blandford  

E-Print Network [OSTI]

.5 Decoding Multiple Gamma Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2.6 Rank of Computer Science Carnegie Mellon University Pittsburgh, PA 15213 Thesis Committee: Guy E. Blelloch, chair fast queries (and updates) to the data. This thesis describes compact representations of several types

287

National Security  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation Desert Southwest Regionat Cornell Batteries &NST DivisionNationalEnergy

288

National Laboratory  

Office of Scientific and Technical Information (OSTI)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "ofEarlyEnergyDepartmentNationalRestart ofMeasuringInformationOffice ofEnergy, OfficeUS Dept

289

National Laboratory  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the Contributions andData andFleetEngineeringAnnual ReportNational Lab Day -

290

National Laboratory  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the Contributions andData andFleetEngineeringAnnual ReportNational Lab Day -draws more

291

Phase Transition in Compact QED(3) and the Josephson Junction  

E-Print Network [OSTI]

We study the finite temperature phase transition in 2+1 dimensional compact QED and its dual theory: Josephson junction. Duality of these theories at zero temperature was established long time ago by Hosotani. Phase transition in compact QED is well studied and we employ the `duality' to study the superconductivity phase transition in a Josephson junction. For a thick junction we obtain a critical temperature in terms of the geometrical properties of the junction.

Vakif K. Onemli; Murat Tas; Bayram Tekin

2001-08-22T23:59:59.000Z

292

WILDLIFE REFUGE BACA NATIONAL  

E-Print Network [OSTI]

Rio Grande National Forest Rio Grande National Forest San Isabel National Forest Solar Energy Study Great Sand Dunes National Preserve 285 160 160 160 285 Carson National Forest Grand Mesa National Forest Note 2) (As of 6/5/2009) Solar Energy Study Area (As of 6/5/2009) BLM Lands Being Analyzed for Solar

Laughlin, Robert B.

293

Diamagnetic pumping near the base of a stellar convection zone  

E-Print Network [OSTI]

The property of inhomogeneous turbulence in conducting fluids to expel large-scale magnetic fields in the direction of decreasing turbulence intensity is shown as important for the magnetic field dynamics near the base of a stellar convection zone. The downward diamagnetic pumping confines a fossil internal magnetic field in the radiative core so that the field geometry is appropriate for formation of the solar tachocline. For the stars of solar age, the diamagnetic confinement is efficient only if the ratio of turbulent magnetic diffusivity of the convection zone to the (microscopic or turbulent) diffusivity of the radiative interiour is larger than 10^5. Confinement in younger stars require still larger diffusivity ratio. The observation of persistent magnetic structures on young solar-type stars can thus provide evidences for the nonexistence of tachoclines in stellar interiors and on the level of turbulence in radiative cores.

L. L. Kitchatinov; G. Rüdiger

2008-02-18T23:59:59.000Z

294

A Fokker-Planck Model of Rotating Stellar Clusters  

E-Print Network [OSTI]

We have developed a two-dimensional orbit averaged Fokker-Planck model of stellar clusters which expands on spherically symmetric one-dimensional models to include rotation and ellipticity. Physical effects such as collisions, finite stellar lifetimes and bar formation (i.e., a non-axisymmetric component of the potential) can also be included. The first use of the model is to study the evolution of dense clusters (rho(r=0)=~10^7 M_sun/pc^3) that may be expected to have existed at the centres of newly-forming galaxies, with the goal of verifying that angular momentum can be removed from the core of the cluster quickly enough so that rotation no longer prevents the formation of a massive (~10^2 M_sun) object. This could act as the seed black hole for the formation of an AGN.

J. Girash

1997-04-05T23:59:59.000Z

295

SUBSTRUCTURE IN THE STELLAR HALOS OF THE AQUARIUS SIMULATIONS  

SciTech Connect (OSTI)

We characterize the substructure in the simulated stellar halos of Cooper et al. which were formed by the disruption of satellite galaxies within the cosmological N-body simulations of galactic halos of the Aquarius project. These stellar halos exhibit a wealth of tidal features: broad overdensities and very narrow faint streams akin to those observed around the Milky Way. The substructures are distributed anisotropically on the sky, a characteristic that should become apparent in the next generation of photometric surveys. The normalized RMS of the density of stars on the sky appears to be systematically larger for our halos compared with the value estimated for the Milky Way from main-sequence turnoff stars in the Sloan Digital Sky Survey. We show that this is likely to be due in part to contamination by faint QSOs and redder main-sequence stars, and might suggest that {approx}10% of the Milky Way halo stars have formed in situ.

Helmi, Amina [Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, 9700 AV Groningen (Netherlands); Cooper, A. P.; Cole, S.; Frenk, C. S. [Institute for Computational Cosmology, Department of Physics, University of Durham, South Road, Durham DH1 3LE (United Kingdom); White, S. D. M. [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Str. 1, D-85748 Garching (Germany); Navarro, J. F., E-mail: ahelmi@astro.rug.nl [Department of Physics and Astronomy, University of Victoria, Victoria, BC V8P 5C2 (Canada)

2011-05-20T23:59:59.000Z

296

Thermal distributions in stellar plasmas, nuclear reactions and solar neutrinos  

E-Print Network [OSTI]

The physics of nuclear reactions in stellar plasma is reviewed with special emphasis on the importance of the velocity distribution of ions. Then the properties (density and temperature) of the weak-coupled solar plasma are analysed, showing that the ion velocities should deviate from the Maxwellian distribution and could be better described by a weakly-nonexstensive (|q-1|solar neutrino fluxes, and on the pp neutrino energy spectrum, and analyse the consequences for the solar neutrino problem.

M. Coraddu; G. Kaniadakis; A. Lavagno; M. Lissia; G. Mezzorani; P. Quarati

1998-11-24T23:59:59.000Z

297

DEEP HUBBLE SPACE TELESCOPE IMAGING IN NGC 6397: STELLAR DYNAMICS  

SciTech Connect (OSTI)

Multi-epoch observations with the Advanced Camera for Surveys on the Hubble Space Telescope provide a unique and comprehensive probe of stellar dynamics within NGC 6397. We are able to confront analytic models of the globular cluster with the observed stellar proper motions. The measured proper motions probe well along the main sequence from 0.8 to below 0.1 M{sub Sun} as well as white dwarfs younger than 1 Gyr. The observed field lies just beyond the half-light radius where standard models of globular cluster dynamics (e.g., based on a lowered Maxwellian phase-space distribution) make very robust predictions for the stellar proper motions as a function of mass. The observed proper motions show no evidence for anisotropy in the velocity distribution; furthermore, the observations agree in detail with a straightforward model of the stellar distribution function. We do not find any evidence that the young white dwarfs have received a natal kick in contradiction with earlier results. Using the observed proper motions of the main-sequence stars, we obtain a kinematic estimate of the distance to NGC 6397 of 2.2{sup +0.5}{sub -0.7} kpc and a mass of the cluster of 1.1 {+-} 0.1 Multiplication-Sign 10{sup 5} M{sub Sun} at the photometric distance of 2.53 kpc. One of the main-sequence stars appears to travel on a trajectory that will escape the cluster, yielding an estimate of the evaporation timescale, over which the number of stars in the cluster decreases by a factor of e, of about 3 Gyr. The proper motions of the youngest white dwarfs appear to resemble those of the most massive main-sequence stars, providing the first direct constraint on the relaxation time of the stars in a globular cluster of greater than or about 0.7 Gyr.

Heyl, J. S.; Richer, H.; Woodley, K. A. [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1 (Canada); Anderson, J.; Dotter, A.; Kalirai, J. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Fahlman, G.; Stetson, P. [Herzberg Institute for Astrophysics, National Research Council, Victoria, BC (Canada); Hurley, J. [Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Hawthorn, VIC 3122 (Australia); Rich, R. M. [Division of Astronomy, University of California, Los Angeles, CA 90095-1562 (United States); Shara, M.; Zurek, D. [American Museum of Natural History, New York, NY 10024-5192 (United States)

2012-12-10T23:59:59.000Z

298

Modern yields per stellar generation: the effect of the IMF  

E-Print Network [OSTI]

Gaseous and stellar metallicities in galaxies are nowadays routinely used to constrain the evolutionary processes in galaxies. This requires the knowledge of the average yield per stellar generation, $y_{\\text{Z}}$, i.e. the quantity of metals that a stellar population releases into the interstellar medium (ISM), which is generally assumed to be a fixed fiducial value. Deviations of the observed metallicity from the expected value of $y_{\\text{Z}}$ are used to quantify the effect of outflows or inflows of gas, or even as evidence for biased metallicity calibrations or inaccurate metallicity diagnostics. Here we show that $\\rm y_{\\text{Z}}$ depends significantly on the Initial Mass Function (IMF), varying by up to a factor larger than three, for the range of IMFs typically adopted in various studies. This, along with the variation of the gas mass fraction restored into the ISM by supernovae ($R$, which also depends on the IMF), may yield to deceiving results, if not properly taken into account. In particular, ...

Vincenzo, Fiorenzo; Belfiore, Francesco; Maiolino, Roberto

2015-01-01T23:59:59.000Z

299

Stellar coronal magnetic fields and star-planet interaction  

E-Print Network [OSTI]

Evidence of magnetic interaction between late-type stars and close-in giant planets is provided by the observations of stellar hot spots rotating synchronously with the planets and showing an enhancement of chromospheric and X-ray fluxes. We investigate star-planet interaction in the framework of a magnetic field model of a stellar corona, considering the interaction between the coronal field and that of a planetary magnetosphere moving through the corona. The energy budget of the star-planet interaction is discussed assuming that the planet may trigger a release of the energy of the coronal field by decreasing its relative helicity. The observed intermittent character of the star-planet interaction is explained by a topological change of the stellar coronal field, induced by a variation of its relative helicity. The model predicts the formation of many prominence-like structures in the case of highly active stars owing to the accumulation of matter evaporated from the planet inside an azimuthal flux rope in ...

Lanza, A F

2009-01-01T23:59:59.000Z

300

The LAMOST Stellar Parameter Pipeline at Peking University --- LSP3  

E-Print Network [OSTI]

We introduce the LAMOST Stellar Parameter Pipeline at Peking University --- LSP3, developed and implemented for the determinations of radial velocity $V_{\\rm r}$ and stellar atmospheric parameters (effective temperature $T_{\\rm eff}$, surface gravity log\\,$g$, metallicity [Fe/H]) for the LAMOST Spectroscopic Survey of the Galactic Anti-center (LSS-GAC). We describe the algorithms of LSP3 and examine the accuracy of parameters yielded by it. The precision and accuracy of parameters yielded are investigated by comparing results of multi-epoch observations and of candidate members of open and globular clusters, with photometric calibration, as well as with independent determinations available from a number of external databases, including the PASTEL archive, the APOGEE, SDSS and RAVE surveys, as well as those released in the LAMOST DR1. The uncertainties of LSP3 parameters are characterized and quantified as a function of the spectral signal-to-noise ratio (SNR) and stellar atmospheric parameters. We conclude th...

Xiang, Maosheng; Yuan, Haibo; Huang, Yang; Huo, Zhiying; Zhang, Huawei; Chen, Bingqiu; Zhang, Huihua; Sun, Ningchen; Wang, Chun; Zhao, Yongheng; Shi, Jianrong; Luo, Ali; Li, Guoping; Wu, Yue; Bai, Zongrui; Zhang, Yong; Hou, Yonghui; Yuan, Hailong; Li, Guangwei

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "national compact stellarator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Automated Stellar Spectral Classification and Parameterization for the Masses  

E-Print Network [OSTI]

Stellar spectroscopic classification has been successfully automated by a number of groups. Automated classification and parameterization work best when applied to a homogeneous data set, and thus these techniques primarily have been developed for and applied to large surveys. While most ongoing large spectroscopic surveys target extragalactic objects, many stellar spectra have been and will be obtained. We briefly summarize past work on automated classification and parameterization, with emphasis on the work done in our group. Accurate automated classification in the spectral type domain and parameterization in the temperature domain have been relatively easy. Automated parameterization in the metallicity domain, formally outside the MK system, has also been effective. Due to the subtle effects on the spectrum, automated classification in the luminosity domain has been somewhat more difficult, but still successful. In order to extend the use of automated techniques beyond a few surveys, we present our current efforts at building a web-based automated stellar spectroscopic classification and parameterization machine. Our proposed machinery would provide users with MK classifications as well as the astrophysical parameters of effective temperature, surface gravity, mean abundance, abundance anomalies, and microturbulence.

Ted von Hippel; Carlos Allende Prieto; Chris Sneden

2002-08-08T23:59:59.000Z

302

Physical Parameterization of Stellar Spectra: The Neural Network Approach  

E-Print Network [OSTI]

We present a technique which employs artificial neural networks to produce physical parameters for stellar spectra. A neural network is trained on a set of synthetic optical stellar spectra to give physical parameters (e.g. T_eff, log g, [M/H]). The network is then used to produce physical parameters for real, observed spectra. Our neural networks are trained on a set of 155 synthetic spectra, generated using the SPECTRUM program written by Gray (Gray & Corbally 1994, Gray & Arlt 1996). Once trained, the neural network is used to yield T_eff for over 5000 B-K spectra extracted from a set of photographic objective prism plates (Bailer-Jones, Irwin & von Hippel 1997a). Using the MK classifications for these spectra assigned by Houk (1975, 1978, 1982, 1988) we have produced a temperature calibration of the MK system based on this set of 5000 spectra. It is demonstrated through the metallicity dependence of the derived temperature calibration that the neural networks are sensitive to the metallicity signature in the real spectra. With further work it is likely that neural networks will be able to yield reliable metallicity measurements for stellar spectra.

Coryn A. L. Bailer-Jones; Mike Irwin; Gerard Gilmore; Ted von Hippel

1997-08-22T23:59:59.000Z

303

Design, prototyping and testing of a compact superconducting double quarter wave crab cavity  

E-Print Network [OSTI]

A novel design of superconducting Crab Cavity was proposed and designed at Brookhaven National Laboratory. The new cavity shape is a Double Quarter Wave or DQWCC. After fabrication and surface treatments, the niobium proof-of-principle cavity was cryogenically tested in a vertical cryostat. The cavity is extremely compact yet has a low frequency of 400 MHz, an essential property for service for the Large Hadron Collider luminosity upgrade. The electromagnetic properties of the cavity are also well matched for this demanding task. The demonstrated deflecting voltage of 4.6 MV is well above the requirement for a crab cavity in the future High Luminosity LHC of 3.34 MV. In this paper we present the design, prototyping and test results of the DQWCC.

Xiao, Binping; Belomestnykh, Sergey; Ben-Zvi, Ilan; Calaga, Rama; Cullen, Chris; Capatina, Ofelia; Hammons, Lee; Li, Zenghai; Marques, Carlos; Skaritka, John; Verdú-Andres, Silvia; Wu, Qiong

2015-01-01T23:59:59.000Z

304

Compact Reversed-Field Pinch Reactors (CRFPR): preliminary engineering considerations  

SciTech Connect (OSTI)

The unique confinement physics of the Reversed-Field Pinch (RFP) projects to a compact, high-power-density fusion reactor that promises a significant reduction in the cost of electricity. The compact reactor also promises a factor-of-two reduction in the fraction of total cost devoted to the reactor plant equipment (i.e., fusion power core (FPC) plus support systems). In addition to operational and developmental benefits, these physically smaller systems can operate economically over a range of total power output. After giving an extended background and rationale for the compact fusion approaches, key FPC subsystems for the Compact RFP Reactor (CRFPR) are developed, designed, and integrated for a minimum-cost, 1000-MWe(net) system. Both the problems and promise of the compact, high-power-density fusion reactor are quantitatively evaluated on the basis of this conceptual design. The material presented in this report both forms a framework for a broader, more expanded conceptual design as well as suggests directions and emphases for related research and development.

Hagenson, R.L.; Krakowski, R.A.; Bathke, C.G.; Miller, R.L.; Embrechts, M.J.; Schnurr, N.M.; Battat, M.E.; LaBauve, R.J.; Davidson, J.W.

1984-08-01T23:59:59.000Z

305

The DPOSS II compact group survey: first spectroscopically confirmed candidates  

E-Print Network [OSTI]

This paper presents the results of a pilot redshift survey of 18 candidate compact groups from the distant DPOSS survey that extends the available surveys of compact groups of galaxies to z ~0.2 in redshift, mainly Hickson Compact Groups and Southern Compact Groups. The goal of our survey was to confirm group membership via redshift information and to measure the characteristic parameters of a representative, albeit small, sample of DPOSS survey groups. Of the 18 candidates observed, seven are found to be indeed isolated compact groups, i.e. groups with 3 or more concordant members and with no neighbouring known cluster, while 7 are chance projection configurations on the sky. Three remaining candidates, despite having 3 or more concordant member galaxies, are located in the neighbourhood of known clusters, while another candidate turned out to be a dense sub-condensation within Abell 0952. The median redshift of our 7 confirmed groups is z ~0.12, to be compared with a median redshift of 0.03 for the local sa...

Pompei, E; Iovino, A

2006-01-01T23:59:59.000Z

306

Compact multiwavelength transmitter module for multimode fiber optic ribbon cable  

DOE Patents [OSTI]

A compact multiwavelength transmitter module for multimode fiber optic ribbon cable, which couples light from an M.times.N array of emitters onto N fibers, where the M wavelength may be distributed across two or more vertical-cavity surface-emitting laser (VCSEL) chips, and combining emitters and multiplexer into a compact package that is compatible with placement on a printed circuit board. A key feature is bringing together two emitter arrays fabricated on different substrates--each array designed for a different wavelength--into close physical proximity. Another key feature is to compactly and efficiently combine the light from two or more clusters of optical emitters, each in a different wavelength band, into a fiber ribbon.

Deri, Robert J. (Pleasanton, CA); Pocha, Michael D. (Livermore, CA); Larson, Michael C. (Goleta, CA); Garrett, Henry E. (Livermore, CA)

2002-01-01T23:59:59.000Z

307

Generating expansion model incorporating compact DC power flow equations  

SciTech Connect (OSTI)

This paper presents a compact method of incorporating the spatial dimension into the generation expansion problem. Compact DC power flow equations are used to provide real-power flow coordination equations. Using these equations the marginal contribution of a generator to th total system loss is formulated as a function of that generator`s output. Incorporating these flow equations directly into the MIP formulation of the generator expansion problem results in a model that captures a generator`s true net marginal cost, one that includes both the cost of generation and the cost of transport. This method contrasts with other methods that iterate between a generator expansion model and an optimal power flow model. The proposed model is very compact and has very good convergence performance. A case study with data from Kenya is used to provide a practical application to the model.

Nderitu, D.G.; Sparrow, F.T.; Yu, Z. [Purdue Inst. for Interdisciplinary Engineering Studies, West Lafayette, IN (United States)

1998-12-31T23:59:59.000Z

308

Anisotropic Compact Stars in $f(T)$ Gravity  

E-Print Network [OSTI]

This paper deals with the theoretical modeling of anisotropic compact stars in the framework of $f(T)$ theory of gravity, where $T$ is torsion scalar. To this end, we have used the exact solutions of Krori and Barua metric to a static spherically symmetric metric. The unknown constants involved in the Krori and Barua metric have been specified by using the masses and radii of compact stars 4$U$1820-30, Her X-1, SAX J 1808-3658. The physical properties of these stars have been analyzed in the framework of $f(T)$ theory. In this setting, we have checked the anisotropic behavior, regularity conditions, stability and surface redshift of the compact stars.

Abbas, G; Zubair, M

2015-01-01T23:59:59.000Z

309

Anisotropic Compact Stars in $f(G)$ Gravity  

E-Print Network [OSTI]

This paper is devoted to study the possibility of forming anisotropic compact stars in"modified Gauss-Bonnet, namely called as $f(G)$ theory of gravity which is one of the strong candidates, responsible for the accelerated expansion of the universe. For this purpose, we have used analytical solution of Krori and Barua metric to the Einstein field equations with anisotropic form of matter and power law model of $f(G)$ gravity. To determine the unknown constants in Krori and Barua metric, we have used the masses and radii of compact stars, 4$U$1820-30, Her X-1, SAX J 1808-3658. The physical behavior of these stars have been analyzed with the observational data. In this setting, we have checked all the regularity conditions and stability the compact stars 4$U$1820-30, Her X-1, SAX J 1808-3658.

G. Abbas; D. Momeni; M. Aamir Ali; R. Myrzakulov; S. Qaisar

2014-12-26T23:59:59.000Z

310

Anisotropic Compact Stars in $f(R)$ Gravity  

E-Print Network [OSTI]

In this paper we have investigated the possibility of forming of anisotropic compact stars in $f(R)$ gravity, one of the competent candidates of dark energy. To this end, we have applied the analytical solution of Krori and Barua metric to a static spherically symmetric spacetime in $f(R)$ gravity. The unknown constants in Krori and Barua metric have been determined by using masses and radii of class of compact stars like 4$U$1820-30, Her X-1, SAX J 1808-3658. The properties of these stars have been analyzes in detail. Furthermore, we have checked the regularity conditions, energy conditions, anisotropic behavior, stability and surface redshift of the compact stars 4$U$1820-30, Her X-1, SAX J 1808-3658.

M. Zubair; G. Abbas

2015-02-06T23:59:59.000Z

311

Anisotropic Compact Stars in $f(T)$ Gravity  

E-Print Network [OSTI]

This paper deals with the theoretical modeling of anisotropic compact stars in the framework of $f(T)$ theory of gravity, where $T$ is torsion scalar. To this end, we have used the exact solutions of Krori and Barua metric to a static spherically symmetric metric. The unknown constants involved in the Krori and Barua metric have been specified by using the masses and radii of compact stars 4$U$1820-30, Her X-1, SAX J 1808-3658. The physical properties of these stars have been analyzed in the framework of $f(T)$ theory. In this setting, we have checked the anisotropic behavior, regularity conditions, stability and surface redshift of the compact stars.

G. Abbas; Afshan Kanwal; M. Zubair

2015-01-22T23:59:59.000Z

312

Anisotropic Compact Stars in $f(G)$ Gravity  

E-Print Network [OSTI]

This paper is devoted to study the possibility of forming anisotropic compact stars in"modified Gauss-Bonnet, namely called as $f(G)$ theory of gravity which is one of the strong candidates, responsible for the accelerated expansion of the universe. For this purpose, we have used analytical solution of Krori and Barua metric to the Einstein field equations with anisotropic form of matter and power law model of $f(G)$ gravity. To determine the unknown constants in Krori and Barua metric, we have used the masses and radii of compact stars, 4$U$1820-30, Her X-1, SAX J 1808-3658. The physical behavior of these stars have been analyzed with the observational data. In this setting, we have checked all the regularity conditions and stability the compact stars 4$U$1820-30, Her X-1, SAX J 1808-3658.

Abbas, G; Ali, M Aamir; Myrzakulov, R; Qaisar, S

2015-01-01T23:59:59.000Z

313

Compact stars in the standard model - and beyond  

E-Print Network [OSTI]

In the context of the standard model of particle physics, there is a definite upper limit to the density of stable compact stars. However, if there is a deeper layer of constituents, below that of quarks and leptons, stability may be re-established far beyond this limiting density and a new class of compact stars could exist. These objects would cause gravitational lensing of white dwarfs and gamma-ray bursts, which might be observable as a diffraction pattern in the spectrum. Such observations could provide means for obtaining new clues about the fundamental particles and the origin of cold dark matter.

F. Sandin

2004-10-18T23:59:59.000Z

314

Infiltration of nickel into alumina compact by electrodeposition  

SciTech Connect (OSTI)

Ni metal was electrodeposited into pores of an alumina compact in the aqueous solution of nickel nitrate/urea/ethylene glycol/ammonium sulfate. The Ni{sup 2+} ions in pores of the alumina compact deposited in proportion to t{sup 0.45}-t{sup 0.61} of deposition time (t) on Au electrode sputtered on the alumina surface. The deposition rate of Ni was higher for direct current than pulsed current Nickel grew dendritically in the alumina pores.

Hirata, Yoshihiro; Kyoda, Hideharu; Iwamoto, Takayuki [Kagoshima Univ. (Japan)

1995-09-01T23:59:59.000Z

315

Compact two-beam push-pull free electron laser  

DOE Patents [OSTI]

An ultra-compact free electron laser comprising a pair of opposed superconducting cavities that produce identical electron beams moving in opposite directions such that each set of superconducting cavities accelerates one electron beam and decelerates the other electron beam. Such an arrangement, allows the energy used to accelerate one beam to be recovered and used again to accelerate the second beam, thus, each electron beam is decelerated by a different structure than that which accelerated it so that energy exchange rather than recovery is achieved resulting in a more compact and highly efficient apparatus.

Hutton, Andrew (Yorktown, VA)

2009-03-03T23:59:59.000Z

316

A study of hand tamper design for compaction of soils  

E-Print Network [OSTI]

Determination Standard Oven Dry Method versus Frying Pan Method Grain Size Distribution Curve Centerville Sand 34 Tamper Comparison Chart: Dry Density after 200 Blows per Square Foot of Layer Dry Density versus Compactive Effort Curve on 3. 0 Inch Square... of Utah revealed that a point exists at which an ultimate density is obtained, and any further increase in compaction effort results in lower than ultimate values. Shear Stress and Beari Ca acit If the resistance in a soil is exceeded by applied loads...

McDonough, Brian

1961-01-01T23:59:59.000Z

317

Plasma Frequency Shift Due to a Slowly Rotating Compact Star  

E-Print Network [OSTI]

We investigate the effects of a slowly rotating compact gravitational source on electron oscillations in a homogeneous electrically neutral plasma in the absence of an external electric or magnetic field. Neglecting the random thermal motion of the electrons we assume the gravitoelectromagnetic approximation to the general theory of relativity for the gravitational field. It is shown that there is a shift in the plasma frequency and hence in the dielectric constant of the plasma due to the gravitomagnetic force. We also give estimates for the difference in the frequency of radially transmitted electromagnetic signals for typical compact star candidates.

Babur M. Mirza; Hamid Saleem

2005-05-10T23:59:59.000Z

318

Compact Orthogonal NMR Field Sensor - Energy Innovation Portal  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation Proposed New SubstationCleanCommunity Involvement and Making aCompact soft x-rayEnergyCompact

319

A compact single-camera system for high-speed, simultaneous 3-D velocity and temperature measurements.  

SciTech Connect (OSTI)

The University of Michigan and Sandia National Laboratories collaborated on the initial development of a compact single-camera approach for simultaneously measuring 3-D gasphase velocity and temperature fields at high frame rates. A compact diagnostic tool is desired to enable investigations of flows with limited optical access, such as near-wall flows in an internal combustion engine. These in-cylinder flows play a crucial role in improving engine performance. Thermographic phosphors were proposed as flow and temperature tracers to extend the capabilities of a novel, compact 3D velocimetry diagnostic to include high-speed thermometry. Ratiometric measurements were performed using two spectral bands of laser-induced phosphorescence emission from BaMg2Al10O17:Eu (BAM) phosphors in a heated air flow to determine the optimal optical configuration for accurate temperature measurements. The originally planned multi-year research project ended prematurely after the first year due to the Sandia-sponsored student leaving the research group at the University of Michigan.

Lu, Louise [University of Michigan, Ann Arbor, MI; Sick, Volker [University of Michigan, Ann Arbor, MI; Frank, Jonathan H.

2013-09-01T23:59:59.000Z

320

Test Area for Remedial Actions (TARA) site characterization and dynamic compaction of low-level radioactive waste trenches  

SciTech Connect (OSTI)

As part of a low-level radioactive waste burial ground stabilization and closure technology demonstration project, a group of five burial trenches in Oak Ridge National Laboratory (ORNL) Solid Waste Storage Area (SWSA) 6 was selected as a demonstration site for testing trench compaction, trench grouting, and trench cap installation and performance. This report focuses on site characterization, trench compaction, and grout-trench leachate compatibility. Trench grouting and cap design and construction will be the subject of future reports. The five trenches, known as the Test Area for Remedial Actions (TARA) site, are contained within a hydrologically isolated area of SWSA 6; for that reason, any effects of stabilization activities on site performance and groundwater quality will be separable from the influence of other waste disposal units in SWSA 6. To obviate the chronic problem of burial trench subsidence and to provide support for an infiltration barrier cap, these five trenches were dynamically compacted by repeated dropping of a 4-ton weight onto each trench from heights of approximately 7 m.

Davis, E.C.; Spalding, B.P.; Lee, S.Y.; Hyder, L.K.

1989-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "national compact stellarator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Brookhaven National Laboratory National Synchrotron Light Source  

E-Print Network [OSTI]

Brookhaven National Laboratory National Synchrotron Light Source Number: Revision: LS-ESH-0027 06 copy of this file is the one on-line in the NSLS ESH website. Before using a printed copy, verify that it is the most current version by checking the document issue date on the NSLS ESH website. BROOKHAVEN NATIONAL

Ohta, Shigemi

322

Evidence for tidal interaction and merger as the origin of galaxy morphology evolution in compact groups  

E-Print Network [OSTI]

We present the results of a morphological study based on NIR images of 25 galaxies, with different levels of nuclear activity, in 8 Compact Groups of Galaxies (CGs). We perform independently two different analysis: a isophotal study and a study of morphological asymmetries. The results yielded by the two analysis are highly consistent. For the first time, it is possible to show that deviations from pure ellipses are produced by inhomogeneous stellar mass distributions related to galaxy interactions and mergers. We find evidence of mass asymmetries in 74% of the galaxies in our sample. In 59% of these cases, the asymmetries come in pairs, and are consistent with tidal effects produced by the proximity of companion galaxies. The symmetric galaxies are generally small in size or mass, inactive, and have an early-type morphology. In 20% of the galaxies we find evidence for cannibalism. In 36% of the early-type galaxies the color gradient is positive (blue nucleus) or flat. Summing up these results, as much as 52% of the galaxies in our sample could show evidence of an on going or past mergers. Our observations suggest that galaxies in CGs merge more frequently under ``dry'' conditions. The high frequency of interacting and merging galaxies observed in our study is consistent with the bias of our sample towards CGs of type B, which represents the most active phase in the evolution of the groups. In these groups we also find a strong correlation between asymmetries and nuclear activity in early-type galaxies. This correlation allows us to identify tidal interactions and mergers as the cause of galaxy morphology transformation in CGs.[abridge

R. Coziol; I. Plauchu-Frayn

2007-02-10T23:59:59.000Z

323

Nevada National Security Site  

Broader source: Energy.gov [DOE]

HISTORYIn 1950, President Truman established what is now known as the Nevada National Security Site (NNSS) to perform nuclear weapons testing activities.  In support of national defense initiatives...

324

National Science Bowl Finals  

SciTech Connect (OSTI)

National Science Bowl finals and awards at the National Building Museum in Washington D.C. Monday 5/3/2010

2010-05-03T23:59:59.000Z

325

National Energy Policy (Complete)  

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

Energy Policy May 2001 Report of the National Energy Policy Development Group Reliable, Affordable, and Environmentally Sound Energy for America's Future Report of the National...

326

National Science Bowl Finals  

ScienceCinema (OSTI)

National Science Bowl finals and awards at the National Building Museum in Washington D.C. Monday 5/3/2010

None

2010-09-01T23:59:59.000Z

327

National Nuclear Security Administration  

Broader source: Energy.gov (indexed) [DOE]

and Related Structures within TA-3 at Los Alamos National Laboratory, Los Alamos, New Mexico U. S. Department of Energy National Nuclear Security Administration Los Alamos Area...

328

EFFECT OF UNCERTAINTIES IN STELLAR MODEL PARAMETERS ON ESTIMATED MASSES AND RADII OF SINGLE STARS  

SciTech Connect (OSTI)

Accurate and precise values of radii and masses of stars are needed to correctly estimate properties of extrasolar planets. We examine the effect of uncertainties in stellar model parameters on estimates of the masses, radii, and average densities of solar-type stars. We find that in the absence of seismic data on solar-like oscillations, stellar masses can be determined to a greater accuracy than either stellar radii or densities; but to get reasonably accurate results the effective temperature, log g, and metallicity must be measured to high precision. When seismic data are available, stellar density is the most well-determined property, followed by radius, with mass the least well-determined property. Uncertainties in stellar convection, quantified in terms of uncertainties in the value of the mixing length parameter, cause the most significant errors in the estimates of stellar properties.

Basu, Sarbani [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States); Verner, Graham A.; Chaplin, William J.; Elsworth, Yvonne, E-mail: sarbani.basu@yale.edu, E-mail: gav@bison.ph.bham.ac.uk, E-mail: w.j.chaplin@bham.ac.uk, E-mail: y.p.elsworth@bham.ac.uk [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom)

2012-02-10T23:59:59.000Z

329

Clementine Star Tracker Stellar Compass: Final report part 1  

SciTech Connect (OSTI)

The Clementine mission provided the first ever complete, systematic surface mapping of the moon from the ultra-violet to the near-infrared regions. More than 1.7 million images of the moon, earth and space were returned from this mission. Two star stracker stellar compasses (star tracker camera + stellar compass software) were included on the spacecraft, serving a primary function of providing angle updates to the guidance and navigation system. These cameras served a secondary function by providing a wide field of view imaging capability for lunar horizon glow and other dark-side imaging data. This 290 g camera using a 576 x 384 focal plane array and a 17 mm entrance pupil, detected and centroided stars as dim and dimmer than 4.5 m{sub v}, providing rms pointing accuracy of better than 100 {mu}rad pitch and yaw and 450 {mu}rad roll. A description of this light-weight, low power star tracker camera along with a summary of lessons learned is presented. Design goals and preliminary on-orbit performance estimates are addressed in terms of meeting the mission`s primary objective for flight qualifying the sensors for future Department of Defense flights. Documentation generated during the design, analysis, build, test and characterization of the star tracker cameras are presented. Collectively, this documentation represents a small library of information for this camera, and may be used as a framework for producing copy units by commercial enterprises, and therefore satisfies a Department of Defense and Department of Energy goal to transfer technology to industry. However, the considerable knowledge gained from the experience of the individuals involved in the system trades, design, analysis, production, testing and characterization of the star tracker stellar compass is not contained in this documentation.

Priest, R.E.; Kordas, J.F.; Lewis, I.T. [and others

1995-07-01T23:59:59.000Z

330

THE MYSTERIOUS SICKLE OBJECT IN THE CARINA NEBULA: A STELLAR WIND INDUCED BOW SHOCK GRAZING A CLUMP?  

SciTech Connect (OSTI)

Optical and near-infrared images of the Carina Nebula show a peculiar arc-shaped feature, which we call the ''Sickle'', next to the B-type star Trumpler 14 MJ 218. We use multi-wavelength observations to explore and constrain the nature and origin of the nebulosity. Using submillimeter data from APEX/LABOCA as well as Herschel far-infrared maps, we discovered a dense, compact clump with a mass of {approx}40 M{sub Sun} located close to the apex of the Sickle. We investigate how the B star MJ 218, the Sickle, and the clump are related. Our numerical simulations show that, in principle, a B-type star located near the edge of a clump can produce a crescent-shaped wind shock front, similar to the observed morphology. However, the observed proper motion of MJ 218 suggests that the star moves with high velocity ({approx}100 km s{sup -1}) through the ambient interstellar gas. We argue that the star is just about to graze along the surface of the clump, and the Sickle is a bow shock induced by the stellar wind, as the object moves supersonically through the density gradient in the envelope of the clump.

Ngoumou, Judith; Preibisch, Thomas; Ratzka, Thorsten; Burkert, Andreas, E-mail: ngoumou@usm.lmu.de [Universitaets-Sternwarte Muenchen, Ludwig-Maximilians-Universitaet, Scheinerstr.1, D-81679 Muenchen (Germany)

2013-06-01T23:59:59.000Z

331

Peering through the stellar wind of IGR J19140+0951 with simultaneous INTEGRAL/RXTE observations  

E-Print Network [OSTI]

We have used the RXTE and INTEGRAL satellites simultaneously to observe the High Mass X-ray binary IGR J19140+0951. The spectra obtained in the 3--80 keV range have allowed us to perform a precise spectral analysis of the system along its binary orbit. The spectral evolution confirms the supergiant nature of the companion star and the neutron star nature of the compact object. Using a simple stellar wind model to describe the evolution of the photoelectric absorption, we were able to restrict the orbital inclination angle in the range 38--75 degrees. This analysis leads to a wind mass-loss rate from the companion star of ~5x 10e-8 Msun/year, consistent with an OB I spectral type. We have detected a soft excess in at least four observations, for the first time for this source. Such soft excesses have been reported in several HMXBs in the past. We discuss the possible origin of this excess, and suggest, based on its spectral properties and occurrences around the superior conjunction, that it may be explained as the reprocessing of the X-ray emission originating from the neutron star by the surrounding ionised gas.

L. Prat; J. Rodriguez; D. C. Hannikainen; S. E. Shaw

2008-06-11T23:59:59.000Z

332

The spin rate of pre-collapse stellar cores: wave driven angular momentum transport in massive stars  

E-Print Network [OSTI]

The core rotation rates of massive stars have a substantial impact on the nature of core collapse supernovae and their compact remnants. We demonstrate that internal gravity waves (IGW), excited via envelope convection during a red supergiant phase or during vigorous late time burning phases, can have a significant impact on the rotation rate of the pre-SN core. In typical ($10 \\, M_\\odot \\lesssim M \\lesssim 20 \\, M_\\odot$) supernova progenitors, IGW may substantially spin down the core, leading to iron core rotation periods $P_{\\rm min,Fe} \\gtrsim 50 \\, {\\rm s}$. Angular momentum (AM) conservation during the supernova would entail minimum NS rotation periods of $P_{\\rm min,NS} \\gtrsim 3 \\, {\\rm ms}$. In most cases, the combined effects of magnetic torques and IGW AM transport likely lead to substantially longer rotation periods. However, the stochastic influx of AM delivered by IGW during shell burning phases inevitably spin up a slowly rotating stellar core, leading to a maximum possible core rotation perio...

Fuller, Jim; Lecoanet, Daniel; Quataert, Eliot

2015-01-01T23:59:59.000Z

333

Analysis of Time Series Using Compact Model-Based Descriptions  

E-Print Network [OSTI]

Analysis of Time Series Using Compact Model-Based Descriptions Hans-Peter Kriegel, Peer Kr this is a combination of the coefficients 1, . . . , 3 representing the three input time series using a function f-of-the-art compression methods. The results are visually presented in a very concise way so that the user can easily

Kriegel, Hans-Peter

334

MissionBased Compact The Commonwealth of Australia  

E-Print Network [OSTI]

;Page 2 CONTENTS Attachments A. Indicative list of Commonwealth Funding provided to the University which is administered by DEEWR and relevant to this Compact. B. List of Commonwealth Funding provided to the University and Workplace Relations and the University about Performance Funding. E. Copy of Commonwealth Grant Scheme

Viglas, Anastasios

335

Compact X-ray Light Source Workshop Report  

SciTech Connect (OSTI)

This report, produced jointly by EMSL and FCSD, is the result of a workshop held in September 2011 that examined the utility of a compact x-ray light source (CXLS) in addressing many scientific challenges critical to advancing energy science and technology.

Thevuthasan, Suntharampillai; Evans, James E.; Terminello, Louis J.; Koppenaal, David W.; Manke, Kristin L.; Plata, Charity

2012-12-01T23:59:59.000Z

336

Compact anhydrous HCl to aqueous HCl conversion system  

DOE Patents [OSTI]

The present invention is directed to an inexpensive and compact apparatus adapted for use with a .sup.196 Hg isotope separation process and the conversion of anhydrous HCl to aqueous HCl without the use of air flow to carry the HCl vapor into the converter system.

Grossman, Mark W. (Belmont, MA); Speer, Richard (S. Hamilton, MA)

1993-01-01T23:59:59.000Z

337

Carbon RRLs Carbon RRLs towards Ultra-compact HII Regions  

E-Print Network [OSTI]

Carbon RRLs Carbon RRLs towards Ultra-compact HII Regions Dana S. Balser D. Anish Roshi (Raman (Agnes Scott College) #12;Carbon RRLs Carbon Radio Recombination Lines (RRLs) NGC 2024 (Orion B) IC 1795 (W3) Palmer et al. (1967) #12;Carbon RRLs Photodissociation Regions (PDRs) Hollenbach & Tielens (1997

Balser, Dana S.

338

SURFING A WAVE TO COMPACT LASER TECHNOLOGY December 10 2007  

E-Print Network [OSTI]

to waves trailing behind a moving boat and small bunches of electrons can gather energy from the waveSURFING A WAVE TO COMPACT LASER TECHNOLOGY December 10 2007 New laser-based technology could laser pulses can be fired into plasma to create a wake and its huge electric fields can be harnessed

Strathclyde, University of

339

Compact Representation of Coordinated Sampling Policies for Body Sensor Networks  

E-Print Network [OSTI]

.Talukder@jpl.nasa.gov Abstract Embedded sensors of a Body Sensor Network need to efficiently utilize their energy resources Department of Electrical Engineering Los Angeles, CA 90089, USA 1-213-821-0871 {lius,raghu}@usc.edu 2 of a compact representation is feasible with little loss in performance. The global optimal policy is computed

Panangadan, Anand

340

DEFINITIONS OF COMPACTNESS AND THE AXIOM OF CHOICE ...  

E-Print Network [OSTI]

Apr 17, 2001 ... the United States and in France: using nets (Birkhoff, building on work by E. H. Moore and H. L. Smith), and ..... no countably infinite subset, and neither does its power set. It follows that (A, ...... [ho] P. Howard, Definitions of compactness, J. Symbolic Logic 55 (1990) 645–655. ... University of Northern Iowa.

1910-20-32T23:59:59.000Z

Note: This page contains sample records for the topic "national compact stellarator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Most new recessed downlights in the commercial sector use compact  

E-Print Network [OSTI]

CFL downlight systems--one each for commercial and residential markets--that reduce both energy: · PIER project site: www.energy.ca.gov/pier/buildings/ projects/500-01-041-0-4-4_3.html · PIER contractorMost new recessed downlights in the commercial sector use compact fluorescent lamps (CFLs

342

Wavelet Occupancy Grids: a Method for Compact Map Building  

E-Print Network [OSTI]

Wavelet Occupancy Grids: a Method for Compact Map Building Manuel Yguel, Olivier Aycard for multi-resolution map building based on wavelets, which we call the wavelet occupancy grid (WavOG). Pai representation and data storage for large maps, under the constraints of multi-sensor real-time updates

Paris-Sud XI, Université de

343

ULTRA-COMPACT ACCELERATOR TECHNOLOGIES FOR APPLICATION IN NUCLEAR TECHNIQUES  

SciTech Connect (OSTI)

We report on compact accelerator technology development for potential use as a pulsed neutron source quantitative post verifier. The technology is derived from our on-going compact accelerator technology development program for radiography under the US Department of Energy and for a clinic sized compact proton therapy systems under an industry sponsored Cooperative Research and Development Agreement. The accelerator technique relies on the synchronous discharge of a prompt pulse generating stacked transmission line structure with the beam transit. The goal of this technology is to achieve {approx}10 MV/m gradients for 10s of nanoseconds pulses and to {approx}100 MV/m gradients for {approx}1 ns systems. As a post verifier for supplementing existing x-ray equipment, this system can remain in a charged, stand-by state with little or no energy consumption. We detail the progress of our overall component development effort with the multilayer dielectric wall insulators (i.e., the accelerator wall), compact power supply technology, kHz repetition-rate surface flashover ion sources, and the prompt pulse generation system consisting of wide-bandgap switches and high performance dielectric materials.

Sampayan, S; Caporaso, G; Chen, Y; Carazo, V; Falabella, S; Guethlein, G; Guse, S; Harris, J R; Hawkins, S; Holmes, C; Krogh, M; Nelson, S; Paul, A C; Pearson, D; Poole, B; Schmidt, R; Sanders, D; Selenes, K; Sitaraman, S; Sullivan, J; Wang, L; Watson, J

2009-06-11T23:59:59.000Z

344

A New Compact Multichannel Receiver for Underwater Wireless Communication Networks  

E-Print Network [OSTI]

size of the proposed receiver makes it particularly useful for small unmanned underwater vehicles1 A New Compact Multichannel Receiver for Underwater Wireless Communication Networks Ali Abdi of the particle velocity, in addition to the pressure, multichannel reception can be accomplished in underwater

Abdi, Ali

345

MIXING RANK-ONE ACTIONS OF LOCALLY COMPACT ABELIAN GROUPS  

E-Print Network [OSTI]

MIXING RANK-ONE ACTIONS OF LOCALLY COMPACT ABELIAN GROUPS Alexandre I. Danilenko and Cesar E. Silva that such transformations are mixing of all orders [Ka], [Ry1] and have minimal self-joinings of all orders [Ki], [Ry1 this progress, not so many concrete examples of rank-one mixing ac- tions are known. Most of them were obtained

Silva, Cesar E.

346

Design and Application of Low Compaction Energy Concrete for  

E-Print Network [OSTI]

Design and Application of Low Compaction Energy Concrete for Use in Slip-form Concrete Paving of cement pastes and the green strength of concretes Slipform self-consolidating concrete (SFSCC) requires sufficient flowability in order to consolidate without the use of internal vibration. However, this concrete

347

Introduction to Compact Riemann Surfaces Alexander I. Bobenko  

E-Print Network [OSTI]

1 Introduction to Compact Riemann Surfaces Alexander I. Bobenko Institut f¨ur Mathematik more self contained. In particular we will deal with classical descriptions of Riemann surfaces, and uniformization techniques. Motivated by the concrete point of view on Riemann surfaces of this book we choose

Bobenko, Alexander I.

348

Disk-shaped Compact Tension Test for Asphalt Concrete Fracture  

E-Print Network [OSTI]

Disk-shaped Compact Tension Test for Asphalt Concrete Fracture by M.P.Wagoner, W.G. Buttlar and G geometry is the ability to test cylindrical cores obtained from in-place asphalt concrete pavements finalizing the specimen geometry, a typical asphalt concrete surface mixture was tested at various

Paulino, Glaucio H.

349

Recent progress on the Compact Ignition Tokamak (CIT)  

SciTech Connect (OSTI)

This report describes work done on the Compact Ignition Tokamak (CIT), both at the Princeton Plasma Physics Laboratory (PPPL) and at other fusion laboratories in the United States. The goal of CIT is to reach ignition in a tokamak fusion device in the mid-1990's. Scientific and engineering features of the design are described, as well as projected cost and schedule.

Ignat, D.W.

1987-01-01T23:59:59.000Z

350

Embedding the bicyclic semigroup into countably compact topological semigroups  

E-Print Network [OSTI]

We study algebraic and topological properties of topological semigroups containing a copy of the bicyclic semigroup $C(p,q)$. We prove that each topological semigroup $S$ with pseudocompact square contains no dense copy of $C(p,q)$. On the other hand, we construct a consistent example of a Tychonov countably compact semigroup containing a copy of $C(p,q)$.

Banakh, Taras; Gutik, Oleg

2008-01-01T23:59:59.000Z

351

Collision of two identical hypersonic stellar winds in binary systems  

E-Print Network [OSTI]

We investigate the hydrodynamics of two identical hypersonic stellar winds in a binary system. The interaction of these winds manifests itself in the form of two shocks and a contact surface between them. We neglect the binary rotation and assume that the gas flow ahead of the shocks is spherically symmetrical. In this case the contact surface that separates the gas emanated from the different stars coincides with the midplane of the binary components. In the shock the gas is heated and flows away nearly along the contact surface. We find the shock shape and the hot gas parameters in the shock layer between the shock and the contact surface.

Nikolay N. Pilyugin; Vladimir V. Usov

2006-10-13T23:59:59.000Z

352

Collision of two identical hypersonic stellar winds in binary systems  

E-Print Network [OSTI]

We investigate the hydrodynamics of two identical hypersonic stellar winds in a binary system. The interaction of these winds manifests itself in the form of two shocks and a contact surface between them. We neglect the binary rotation and assume that the gas flow ahead of the shocks is spherically symmetrical. In this case the contact surface that separates the gas emanated from the different stars coincides with the midplane of the binary components. In the shock the gas is heated and flows away nearly along the contact surface. We find the shock shape and the hot gas parameters in the shock layer between the shock and the contact surface.

Pilyugin, N N; Pilyugin, Nikolay N.; Usov, Vladimir V.

2006-01-01T23:59:59.000Z

353

Statistical Confirmation of a Stellar Upper Mass Limit  

E-Print Network [OSTI]

We derive the expectation value for the maximum stellar mass (m_max) in an ensemble of N stars, as a function of the IMF upper-mass cutoff (m_up) and N. We statistically demonstrate that the upper IMF of the local massive star census observed thus far in the Milky Way and Magellanic Clouds clearly exhibits a universal upper mass cutoff around 120 - 200 M_sun for a Salpeter IMF, although the result is more ambiguous for a steeper IMF.

M. S. Oey; C. J. Clarke

2005-01-07T23:59:59.000Z

354

The characteristic stellar mass as a function of redshift  

E-Print Network [OSTI]

We present a model for the star formation process during the initial collapse of dark matter haloes at redshifts z=0-30. We derive a simple expression for the characteristic stellar mass scale during this initial burst of star formation. In our picture, this characteristic scale reflects both the minimum temperature to which the gas can cool (determined by the metallicity and the temperature of the cosmic microwave background) and the pressure of overlying baryons in the collapsing halo. This prescription reproduces both the large mass scales found in simulations of Population III star formation and the near solar values observed for star formation at low redshift.

Cathie J. Clarke; Volker Bromm

2003-05-11T23:59:59.000Z

355

Stellar Velocity Dispersion of the Leo A Dwarf Galaxy  

E-Print Network [OSTI]

We measure the first stellar velocity dispersion of the Leo A dwarf galaxy, \\sigma = 9.3 +- 1.3 km/s. We derive the velocity dispersion from the radial velocities of ten young B supergiants and two HII regions in the central region of Leo A. We estimate a projected mass of 8 +- 2.7 x10^7 solar masses within a radius of 2 arcmin, and a mass to light ratio of at least 20 +- 6 M_sun/L_sun. These results imply Leo A is at least ~80% dark matter by mass.

Warren R. Brown; Margaret J. Geller; Scott J. Kenyon; Michael J. Kurtz

2007-05-08T23:59:59.000Z

356

A Large Stellar Evolution Database for Population Synthesis Studies. III. Inclusion of the full Asymptotic Giant Branch phase and Web tools for stellar population analyses  

E-Print Network [OSTI]

Stellar evolution tracks and isochrones are key inputs for a wide range of astrophysical studies; in particular, they are essential to the interpretation of photometric and spectroscopic observations of resolved and unresolved stellar populations. We have made available to the astrophysical community a large, homogenous database of up-to-date stellar tracks and isochrones, and a set of programs useful in population synthesis studies. In this paper we first summarize the main properties of our stellar model database (BaSTI) already introduced in Pietrinferni et al. (2004) and Pietrinferni et al. (2006). We then discuss an important update of the database, i.e., the extension of all stellar models and isochrones until the end of the thermal pulses along the Asymptotic Giant Branch. This extension of the library is particularly relevant for stellar population analyses in the near-infrared, or longer wavelengths, where the contribution to the integrated photometric properties by cool and bright Asymptotic Giant Branch stars is significant. A few comparisons with empirical data are also presentend and briefly discussed. We then present three web-tools that allow an interactive access to the database, and make possible to compute user-specified evolutionary tracks, isochrones, stellar luminosity functions, plus synthetic Color-Magnitude-Diagrams and integrated magnitudes for arbitrary Star Formation Histories. All these web tools are available at the BaSTI database official site: http://www.oa-teramo.inaf.it/BASTI.

Daniel Cordier; Adriano Pietrinferni; Santi Cassisi; Maurizio Salaris

2006-12-21T23:59:59.000Z

357

Confirmed: Stellar Behemoth Self-Destructs in Type IIb Supernova  

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

National Laboratory (Berkeley Lab), to expose fleeting cosmic events such as supernovae. For the first time ever, scientists have direct confirmation that a Wolf-Rayet...

358

E-Print Network 3.0 - astrophysics stellar collapse Sample Search...  

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

in stellar collapse; elements of the general theory of relativity... -8576; Internet: dmw@pas.rochester.edu. Textbook: Brad Carroll and Dale Ostlie, Modern ... Source: Watson,...

359

Ceramographic Examinations of Irradiated AGR-1 Fuel Compacts  

SciTech Connect (OSTI)

The AGR 1 experiment involved irradiating 72 cylindrical fuel compacts containing tri-structural isotropic (TRISO)-coated particles to a peak burnup of 19.5% fissions per initial metal atom with no in-pile failures observed out of almost 300,000 particles. Six irradiated AGR 1 fuel compacts were selected for microscopy that span a range of irradiation conditions (temperature, burnup, and fast fluence). These six compacts also included all four TRISO coating variations irradiated in the AGR experiment. The six compacts were cross-sectioned both transversely and longitudinally, mounted, ground, and polished after development of careful techniques for preserving particle structures against preparation damage. From 36 to 79 particles within each cross section were exposed near enough to midplane for optical microscopy of kernel, buffer, and coating behavior. The microstructural analysis focused on kernel swelling and porosity, buffer densification and fracture, debonding between the buffer and inner pyrolytic carbon (IPyC) layers, and fractures in the IPyC and SiC layers. Three basic particle morphologies were established according to the extent of bonding between the buffer and IPyC layers: complete debonding along the interface (Type A), no debonding along the interface (Type B), and partial debonding (Type AB). These basic morphologies were subdivided according to whether the buffer stayed intact or fractured. The resulting six characteristic morphologies were used to classify particles within each cross section, but no spatial patterns were clearly observed in any of the cross-sectional morphology maps. Although positions of particle types appeared random within compacts, examining a total of 931 classified particles allowed other relationships among morphological types to be established.

Paul Demkowicz; Scott Ploger; John Hunn; Jay S. Kehn

2012-09-01T23:59:59.000Z

360

Ceramographic Examinations of Irradiated AGR-1 Fuel Compacts  

SciTech Connect (OSTI)

The AGR 1 experiment involved irradiating 72 cylindrical fuel compacts containing tri-structural isotropic (TRISO)-coated particles to a peak burnup of 19.5% fissions per initial metal atom with no in-pile failures observed out of almost 300,000 particles. Five irradiated AGR 1 fuel compacts were selected for microscopy that span a range of irradiation conditions (temperature, burnup, and fast fluence). These five compacts also included all four TRISO coating variations irradiated in the AGR experiment. The five compacts were cross-sectioned both transversely and longitudinally, mounted, ground, and polished after development of careful techniques for preserving particle structures against preparation damage. Approximately 40 to 80 particles within each cross section were exposed near enough to mid-plane for optical microscopy of kernel, buffer, and coating behavior. The microstructural analysis focused on kernel swelling and porosity, buffer densification and fracture, debonding between the buffer and inner pyrolytic carbon (IPyC) layers, and fractures in the IPyC and SiC layers. Three basic particle morphologies were established according to the extent of bonding between the buffer and IPyC layers: complete debonding along the interface (Type A), no debonding along the interface (Type B), and partial debonding (Type AB). These basic morphologies were subdivided according to whether the buffer stayed intact or fractured. The resulting six characteristic morphologies were used to classify particles within each cross section, but no spatial patterns were clearly observed in any of the cross-sectional morphology maps. Although positions of particle types appeared random within compacts, examining a total of 830 classified particles allowed other relationships among morphological types to be established.

Paul Demkowicz; Scott Ploger; John Hunn

2012-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "national compact stellarator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

High-volume natural volcanic pozzolan and limestone powder as partial replacements for portland cement in self-compacting and sustainable concrete  

E-Print Network [OSTI]

the resulting self-compacting concrete (SCC). Petrographicity, which satisfy self-compacting concrete criteria withoutcement in self-compacting and sustainable concrete K. Celik

2014-01-01T23:59:59.000Z

362

A FIRST LOOK AT THE AURIGA-CALIFORNIA GIANT MOLECULAR CLOUD WITH HERSCHEL AND THE CSO: CENSUS OF THE YOUNG STELLAR OBJECTS AND THE DENSE GAS  

SciTech Connect (OSTI)

We have mapped the Auriga/California molecular cloud with the Herschel PACS and SPIRE cameras and the Bolocam 1.1 mm camera on the Caltech Submillimeter Observatory with the eventual goal of quantifying the star formation and cloud structure in this giant molecular cloud (GMC) that is comparable in size and mass to the Orion GMC, but which appears to be forming far fewer stars. We have tabulated 60 compact 70/160 {mu}m sources that are likely pre-main-sequence objects and correlated those with Spitzer and WISE mid-IR sources. At 1.1 mm, we find 18 cold, compact sources and discuss their properties. The most important result from this part of our study is that we find a modest number of additional compact young objects beyond those identified at shorter wavelengths with Spitzer. We also describe the dust column density and temperature structure derived from our photometric maps. The column density peaks at a few Multiplication-Sign 10{sup 22} cm{sup -2} (N {sub H2}) and is distributed in a clear filamentary structure along which nearly all of the pre-main-sequence objects are found. We compare the young stellar object surface density to the gas column density and find a strong nonlinear correlation between them. The dust temperature in the densest parts of the filaments drops to {approx}10 K from values {approx}14-15 K in the low-density parts of the cloud. We also derive the cumulative mass fraction and probability density function of material in the cloud, which we compare with similar data on other star-forming clouds.

Harvey, Paul M. [Astronomy Department, University of Texas at Austin, 1 University Station C1400, Austin, TX 78712-0259 (United States)] [Astronomy Department, University of Texas at Austin, 1 University Station C1400, Austin, TX 78712-0259 (United States); Fallscheer, Cassandra [Department of Physics and Astronomy, University of Victoria, 3800 Finnerty Road, Victoria, BC V8P 5C2 (Canada)] [Department of Physics and Astronomy, University of Victoria, 3800 Finnerty Road, Victoria, BC V8P 5C2 (Canada); Ginsburg, Adam [Center for Astrophysics and Space Astronomy, University of Colorado, 389 UCB, Boulder, CO 80309-0389 (United States)] [Center for Astrophysics and Space Astronomy, University of Colorado, 389 UCB, Boulder, CO 80309-0389 (United States); Terebey, Susan [Department of Physics and Astronomy PS315, 5151 State University Drive, California State University at Los Angeles, Los Angeles, CA 90032 (United States)] [Department of Physics and Astronomy PS315, 5151 State University Drive, California State University at Los Angeles, Los Angeles, CA 90032 (United States); Andre, Philippe; Koenyves, Vera [Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, IRFU/Service d'Astrophysique, CEA Saclay, F-91191 Gif-sur-Yvette (France)] [Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, IRFU/Service d'Astrophysique, CEA Saclay, F-91191 Gif-sur-Yvette (France); Bourke, Tyler L. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)] [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Di Francesco, James; Matthews, Brenda C. [Herzberg Institute of Astrophysics, National Research Council of Canada, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada)] [Herzberg Institute of Astrophysics, National Research Council of Canada, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada); Peterson, Dawn E., E-mail: pmh@astro.as.utexas.edu, E-mail: Cassandra.Fallscheer@nrc-cnrc.gc.ca, E-mail: adam.ginsburg@colorado.edu, E-mail: sterebe@calstatela.edu, E-mail: pandre@cea.fr, E-mail: vera.konyves@cea.fr, E-mail: tbourke@cfa.harvard.edu, E-mail: James.DiFrancesco@nrc-cnrc.gc.ca, E-mail: Brenda.Matthews@nrc-cnrc.gc.ca, E-mail: dpeterson@spacescience.org [Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO 80303 (United States)

2013-02-20T23:59:59.000Z

363

Northwest Interstate Compact on Low-Level Radioactive Waste Management (Multiple States)  

Broader source: Energy.gov [DOE]

The Northwest Interstate Compact on Low-Level Radioactive Waste Management, enacted in 1981, was ratified by Congress in 1985. The Compact is a cooperative effort of the party states to protect...

364

Compaction Effects on Uniformity, Moisture Diffusion, and Mechanical Properties of Asphalt Pavements  

E-Print Network [OSTI]

Field compaction of asphalt mixtures is an important process that influences performance of asphalt pavements; however there is very little effort devoted to evaluate the influence of compaction on the uniformity and properties of asphalt mixtures...

Kassem, Emad Abdel-Rahman Ahmed

2011-08-08T23:59:59.000Z

365

Acoustic emission and compaction creep of quartz sand at subcritical stress  

E-Print Network [OSTI]

Time-dependent fluid-assisted mechanisms such as stress-induced dissolution and subcritical crack growth play an important role in porosity reduction and compaction of granular material in nature. Previous compaction creep experiments on loosely...

Lenz, Steven Christopher

2002-01-01T23:59:59.000Z

366

E-Print Network 3.0 - advanced compact accelerator Sample Search...  

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

Physics 27 By-Products Utilization Summary: Center for By-Products Utilization SELF-COMPACTING CONCRETE (SCC) OR SELF- LEVELING CONCRETE (SLC... - MILWAUKEE 12;2 SELF-COMPACTING...

367

Safe and compact ammonia storage/delivery systems for SCR-DeNOX...  

Office of Environmental Management (EM)

Safe and compact ammonia storagedelivery systems for SCR-DeNOX in automotive units Safe and compact ammonia storagedelivery systems for SCR-DeNOX in automotive units Presentation...

368

The Expulsion of Stellar Envelopes in Core-Collapse Supernovae  

E-Print Network [OSTI]

We examine the relation between presupernova stellar structure and the distribution of ejecta in core-collapse supernovae, assuming adiabatic, spherically symmetric flow. We develop a simple yet accurate formula for the blastwave shock velocity, and demonstrate that the entire final density distribution can be approximated with simple models for the final pressure distribution, along with the approximate shock-deposited entropy, in a way that matches the results of simulations. We find that the distribution of density in a star's ejecta depends on whether its outer envelope is radiative or convective, and if convective, on the composition structure of the star; simple approximate forms are presented for red and blue supergiant ejecta. Our models are most accurate for the high-velocity ejecta from the periphery of a star, where the shock dynamics are predictable. We present formulae for the final density distribution of this material, for both radiative and efficiently convective envelopes. These formulae limit to the well-known planar, self-similar solutions for mass shells approaching the stellar surface. But, the assumption of adiabatic flow fails at low optical depth, so this planar limit need not be attained. Formulae are given for the observable properties of the X-ray burst accompanying shock emergence, and their dependence on the parameters of the explosion. Motivated by the relativistic expansion recently inferred by Kulkarni et al. (1998) for the synchrotron shell around SN1998bw, we estimate the criterion for relativistic mass ejection and the rest mass of relativistic ejecta.

Christopher D. Matzner; Christopher F. McKee

1998-07-04T23:59:59.000Z

369

Can stellar wobble in triple systems mimic a planet?  

E-Print Network [OSTI]

The first extrasolar planets have been detected by the measurement of the wobble of the parent star. This wobble leads to the periodic modulation of three observables: the radial velocity, the position on the sky and the time of arrival of periodic signals. We show that the same wobble, and therefore the same modulation of the three observables, can be due to the presence of a more distant binary stellar companion. Thus, the observation of the wobble does not, by itself, constitute a proof of a planet detection. In particular, astrometric confirmation of a wobble does not necessarily provide a sufficient proof of the existence of a planet candidate detected by radial velocity. Additional conditions, which we discuss here, must be fulfilled. We investigate the observed wobble for the planet candidates already detected and we find that, for each case, a wobble due to a binary stellar companion can be excluded. But for apparent Saturn-like planets in wide orbits, there may be an ambiguity in future detections, especially in spaceborne astrometric missions. We conclude that, in some cases, a definitive proof for the presence of a planet requires further observations such as direct imaging.

J. Schneider; J. Cabrera

2005-09-13T23:59:59.000Z

370

The Formation of Brown Dwarfs as Ejected Stellar Embryos  

E-Print Network [OSTI]

We conjecture that brown dwarfs are substellar objects because they have been ejected from small newborn multiple systems which have decayed in dynamical interactions. In this view, brown dwarfs are stellar embryos for which the star formation process was aborted before the hydrostatic cores could build up enough mass to eventually start hydrogen burning. The disintegration of a small multiple system is a stochastic process, which can be described only in terms of the half-life of the decay. A stellar embryo competes with its siblings in order to accrete infalling matter, and the one that grows slowest is most likely to be ejected. With better luck, a brown dwarf would therefore have become a normal star. This interpretation of brown dwarfs readily explains the rarity of brown dwarfs as companions to normal stars (aka the ``brown dwarf desert''), the absence of wide brown dwarf binaries, and the flattening of the low mass end of the initial mass function. Possible observational tests of this scenario include statistics of brown dwarfs near Class 0 sources, and the kinematics of brown dwarfs in star forming regions while they still retain a kinematic signature of their expulsion. Because the ejection process limits the amount of gas brought along in a disk, it is predicted that substellar equivalents to the classical T Tauri stars should be very rare.

Bo Reipurth; Cathie Clarke

2001-03-01T23:59:59.000Z

371

Models of Forbidden Line Emission Profiles from Axisymmetric Stellar Winds  

E-Print Network [OSTI]

A number of strong infrared forbidden lines have been observed in several evolved Wolf-Rayet star winds, and these are important for deriving metal abundances and testing stellar evolution models. In addition, because these optically thin lines form at large radius in the wind, their resolved profiles carry an imprint of the asymptotic structure of the wind flow. This work presents model forbidden line profile shapes formed in axisymmetric winds. It is well-known that an optically thin emission line formed in a spherical wind expanding at constant velocity yields a flat-topped emission profile shape. Simulated forbidden lines are produced for a model stellar wind with an axisymmetric density distribution that treats the latitudinal ionization self-consistently and examines the influence of the ion stage on the profile shape. The resulting line profiles are symmetric about line centre. Within a given atomic species, profile shapes can vary between centrally peaked, doubly peaked, and approximately flat-topped in appearance depending on the ion stage (relative to the dominant ion) and viewing inclination. Although application to Wolf-Rayet star winds is emphasized, the concepts are also relevant to other classes of hot stars such as luminous blue variables and Be/B[e] stars.

Richard Ignace; Adam Brimeyer

2006-05-10T23:59:59.000Z

372

An Orbit Fit for the Grillmair Dionatos Cold Stellar Stream  

SciTech Connect (OSTI)

We use velocity and metallicity information from Sloan Digital Sky Survey and Sloan Extension for Galactic Understanding and Exploration stellar spectroscopy to fit an orbit to the narrow 63{sup o} stellar stream of Grillmair and Dionatos. The stars in the stream have a retrograde orbit with eccentricity e = 0.33 (perigalacticon of 14.4 kpc and apogalacticon of 28.7 kpc) and inclination approximately i {approx} 35{sup o}. In the region of the orbit which is detected, it has a distance of about 7-11 kpc from the Sun. Assuming a standard disk plus bulge and logarithmic halo potential for the Milky Way stars plus dark matter, the stream stars are moving with a large space velocity of approximately 276 km s{sup -1} at perigalacticon. Using this stream alone, we are unable to determine if the dark matter halo is oblate or prolate. The metallicity of the stream is [Fe/H] = -2.1 {+-} 0.1. Observed proper motions for individual stream members above the main sequence turnoff are consistent with the derived orbit. None of the known globular clusters in the Milky Way have positions, radial velocities, and metallicities that are consistent with being the progenitor of the GD-1 stream.

Willett, Benjamin A.; Newberg, Heidi Jo; Zhang, Haotong; Yanny, Brian; Beers, Timothy C.

2009-01-01T23:59:59.000Z

373

Discovery of a Faint Old Stellar System at 150 kpc  

E-Print Network [OSTI]

We report the detection of a faint old stellar system at $(\\alpha,\\delta)=(194.29^\\circ,~34.32^\\circ)$ (SDSS J1257+3419), based on the spatial distribution of bright red-giant branch stars in the Sloan Digital Sky Survey Data Release 4. SDSS J1257+3419 has a half-light radius of $38\\pm 12$ pc and an absolute integrated $V$-magnitude of $M_V=-4.8^{+1.4}_{-1.0}$ mag at a heliocentric distance of $150\\pm 15$ kpc. A comparison between SDSS J1257+3419 and known Galactic halo objects suggests that SDSS J1257+3419 is either (a) a faint and small dwarf galaxy or (b) a faint and widely extended globular cluster. In the former case, SDSS J1257+3419 could represent an entity of a postulated subhalo of the Milky Way. Further photometric and dynamical study of this stellar system is vital to discriminate these possibilities.

T. Sakamoto; T. Hasegawa

2006-10-29T23:59:59.000Z

374

Extended supernova shock breakout signals from inflated stellar envelopes  

E-Print Network [OSTI]

Stars close to the Eddington luminosity can have large low-density inflated envelopes. We show that the rise times of shock breakout signals from supernovae can be extended significantly if supernova progenitors have an inflated stellar envelope. If the shock breakout occurs in such inflated envelopes, the shock breakout signals diffuse in them, and their rise time can be significantly extended. Then, the rise times of the shock breakout signals are dominated by the diffusion time in the inflated envelope rather than the light-crossing time of the progenitors. We show that our inflated Wolf-Rayet star models whose radii are of the order of the solar radius can have shock breakout signals which are longer than ~100 sec. The existence of inflated envelopes in Wolf-Rayet supernova progenitors may be related to the mysterious long shock breakout signal observed in Type Ib SN 2008D. Extended shock breakout signals may provide evidence for the existence of inflated stellar envelopes and can be used to constrain the...

Moriya, Takashi J; Langer, Norbert

2015-01-01T23:59:59.000Z

375

National Renewable Energy Laboratory  

E-Print Network [OSTI]

National Renewable Energy Laboratory Innovation for Our Energy Future ponsorship Format Reversed Color:White rtical Format Reversed-A ertical Format Reversed-B National Renewable Energy Laboratory National Renewable Energy Laboratory Innovation for Our Energy Future National Renewable Energy Laboratory

376

E-Print Network 3.0 - aeropropulsion compact lightweight Sample...  

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

has developed a true 3- component technique, no calibration, compact instrumentation... Hydro--propulsion Aeropropulsion Aero--propulsionpropulsion Micro jet...

377

Mojave National Preserve Joshua Tree National Park  

E-Print Network [OSTI]

Forest (SBNF) Angeles National Forest (ANF) Cleveland National Forest (CNF) CNF CNF SBNF ANF CACA 049111°0'0"N 34°0'0"N 34°0'0"N 33°0'0"N 33°0'0"N California Desert Conservation Area BLM Solar Energy Project Contingent Corridor Deleted Corridor Land Status BLM National Park Service Forest Service Military USFWS

Laughlin, Robert B.

378

Prediction of Asphalt Mixture Compactability from Mixture, Asphalt, and Aggregate Properties  

E-Print Network [OSTI]

. Predicted Plot of CV Neural Net of Entire Data Set for a ............................ 50 Figure 32. Predicted Plot of CV Neural Net of Entire Data Set for AV Nini ................... 51 Figure 33. a versus Predicted a... ................................................... 24 Table 5 HMA Mixing and Compaction Temperatures ............................................. 27 Table 6 Compaction Parameters a, c, and AV Nini ................................................... 38 Table 7 Compaction Parameters m1, m2...

Muras, Andrew J.

2010-07-14T23:59:59.000Z

379

CorrectedProof DETERMINATION OF THE RHEOLOGICAL PARAMETERS OF SELF-COMPACTING  

E-Print Network [OSTI]

CorrectedProof DETERMINATION OF THE RHEOLOGICAL PARAMETERS OF SELF-COMPACTING CONCRETE MATRIX USING version: 7.7.2010 Abstract: The classification of a concrete mixture as self-compacting (SCC) is performed time with viscosity. Key words: self compacting concrete, rheology, slump flow, yield stress

Georgiou, Georgios

380

Mechanical properties of self-compacting concrete reinforced with polypropylene fibres  

E-Print Network [OSTI]

Mechanical properties of self-compacting concrete reinforced with polypropylene fibres O. Gencel*1 of workability. Self-compacting concrete (SCC) is an innovative concrete that is able to flow under its own engineers to incorporate many materials into it. A variety of types of concrete exist.7 Self-compacting

North Texas, University of

Note: This page contains sample records for the topic "national compact stellarator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Design and Development of Integrated Compact Multiphase Separation System (CMSS)  

SciTech Connect (OSTI)

The petroleum industry has relied in the past mainly on conventional vessel-type separators, which are bulky, heavy and expensive, to process wellhead production of oil-water-gas flow. Economic and operational pressures continue to force the petroleum industry to seek less expensive and more efficient separation alternatives in the form of compact separators. The compact dimensions, smaller footprint and lower weight of compact separators have a potential for cost savings to the industry, especially in offshore and subsea applications. Also, compact separators reduce the inventory of hydrocarbons significantly, which is critical for environmental This report presents a brief overview of the activities and tasks accomplished during the Budget Period II (October 09, 2004-April 30, 2006) of the DOE project titled ''Design and Development of Integrated Compact Multiphase Separation System (CMSS{copyright})''. An executive summary is presented initially followed by the tasks of the current budget period. Then, detailed description of the experimental and modeling investigations are presented. Subsequently, the technical and scientific results of the activities of this project period are presented with discussions. The findings of this investigation are summarized in the ''Conclusions'' section In this investigation, the concept of CMSS{copyright} has been developed and is proven through simulation studies and validated by experimental data. As part of the second phase of the project (Budget Period II--10/09/2004-04/30/2006) experimental investigation of the integrated CMSS{copyright} for different configurations has been conducted in order to evaluate the performance of the individual separation components, and determine how they will affect the performance of each other when integrated in the CMSS{copyright}. An intelligent control system is also developed to improve the total system efficiency of Compact Multiphase Separation System (CMSS{copyright}). In mature oil fields, water handling poses a huge problem. Thus water knock out at the earliest stage helps in significant cost savings during handling, separation and transportation of oil. One of the objectives of the CMSS{copyright} configuration is to knock out free water from the upstream fluids. The results from theoretical and experimental studies show that Free Water Knock Out (FWKO) CMSS{copyright} system can be readily deployed in the field using the control system strategies designed, implemented and tested in this study.

Ram S. Mohan; Ovadia Shoham

2006-04-30T23:59:59.000Z

382

Sandia National Laboratories: National Rotor Testbed Functional...  

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

of the National Rotor Testbed: An Aeroelastically Relevant Research-Scale Wind Turbine Rotor." Approximately 60 researchers from various institutions and countries attended...

383

Dartmouth Stellar Evolution Database and the ACS Survey of Galactic Globular Clusters II. Stellar Evolution Tracks, Isochrones, Luminosity Functions, and Synthetic Horizontal-Branch Models  

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

Web tools are also available at the home page (http://stellar.dartmouth.edu/~models/index.html). These tools allow users to create isochrones and convert them to luminosity functions or create synthetic horizontal branch models.

Dotter, A; Chaboyer, B; Jevremovic, D; Kostov, V; Baron, E; Ferguson, J; Sarajedini, A; Anderson, J

384

Lithium in cool stellar atmospheres: Big bang nucleosynthesis and extrasolar planets  

E-Print Network [OSTI]

Lithium in cool stellar atmospheres: Big bang nucleosynthesis and extrasolar planets Matthias Steffen and Elisabetta Caffau Sternphysik In metal-poor stellar atmospheres, the Lithium line at 6707 Ã?-NLTE, respectively. The accurate spectroscopic determination of the Lithium abundance and in particular the 6Li/7Li

385

Stellar Coronae in the Chandra and XMM-Newton Era ASP Conference Series, Vol. TBD, 2001  

E-Print Network [OSTI]

heating remains one of the most fundamental problems in stellar (and solar) astrophysics. The subject has of ares suÃ?ces to heat the apparently non aring coronae. 2. Flare Energy Distributions Solar observations. Recent solar and stellar studies suggest that statistical ares may play a fundamental role

Guedel, Manuel

386

The Atlas3D project --III. A census of the stellar angular momentum within the  

E-Print Network [OSTI]

The Atlas3D project -- III. A census of the stellar angular momentum within the effective radius style file v2.2) The ATLAS3D project ­ III. A census of the stellar angular momentum within¨ur extraterrestrische Physik, PO Box 1312, D-85478 Garching, Germany 8Space Telescope European Coordinating Facility

Bureau, Martin

387

NEUTRON IZATI ON, LEPTON ESCAPE,AND STELLAR HYDRODYNAMICS* W. David Arnett  

E-Print Network [OSTI]

NEUTRON IZATI ON, LEPTON ESCAPE,AND STELLAR HYDRODYNAMICS* W. David Arnett Enrico Fermi Institute University of Chicago 1. The Process of Neutronization.-Aftersili- con burning stellar matter has roughly equal numbers of neutrons and protons. Because neutron-star matter has a large excess of neutrons

Boyer, Edmond

388

THE COMPACT, TIME-VARIABLE RADIO SOURCE PROJECTED INSIDE W3(OH): EVIDENCE FOR A PHOTOEVAPORATED DISK?  

SciTech Connect (OSTI)

We present new Karl G. Jansky Very Large Array (VLA) observations of the compact ({approx}0.''05), time-variable radio source projected near the center of the ultracompact H II region W3(OH). The analysis of our new data as well as of VLA archival observations confirms the variability of the source on timescales of years and for a given epoch indicates a spectral index of {alpha} = 1.3 {+-} 0.3 (S{sub {nu}}{proportional_to}{nu}{sup {alpha}}). This spectral index and the brightness temperature of the source ({approx}6500 K) suggest that we are most likely detecting partially optically thick free-free radiation. The radio source is probably associated with the ionizing star of W3(OH), but an interpretation in terms of an ionized stellar wind fails because the detected flux densities are orders of magnitude larger than expected. We discuss several scenarios and tentatively propose that the radio emission could arise in a static ionized atmosphere around a fossil photoevaporated disk.

Dzib, Sergio A.; Rodriguez-Garza, Carolina B.; Rodriguez, Luis F.; Kurtz, Stan E.; Loinard, Laurent; Zapata, Luis A.; Lizano, Susana, E-mail: s.dzib@crya.unam.mx [Centro de Radiostronomia y Astrofisica, Universidad Nacional Autonoma de Mexico, Morelia 58089 (Mexico)

2013-08-01T23:59:59.000Z

389

Fracture toughness measurements with subsize disk compact specimens  

SciTech Connect (OSTI)

Special fixtures and test methods have been developed for testing small disk compact specimens (1.25 mm diam by 4.6 mm thick). Specimens of European type 316L austenitic stainless steel were irradiated to damage levels of about 3 dpa at nominal irradiation temperatures of either 90 or 250 C and tested over a temperature range from 20 to 250 C. Results show that irradiation to this dose level at these temperatures reduces the fracture toughness but the toughness remains quite high. The toughness decreases as the test temperature increases. Irradiation at 250 C is more damaging than at 90 C, causing larger decreases in the fracture toughness. The testing shows that it is possible to generate useful fracture toughness data with a small disk compact specimens.

Alexander, D.J.

1994-12-31T23:59:59.000Z

390

Compact and mobile high resolution PET brain imager  

DOE Patents [OSTI]

A brain imager includes a compact ring-like static PET imager mounted in a helmet-like structure. When attached to a patient's head, the helmet-like brain imager maintains the relative head-to-imager geometry fixed through the whole imaging procedure. The brain imaging helmet contains radiation sensors and minimal front-end electronics. A flexible mechanical suspension/harness system supports the weight of the helmet thereby allowing for patient to have limited movements of the head during imaging scans. The compact ring-like PET imager enables very high resolution imaging of neurological brain functions, cancer, and effects of trauma using a rather simple mobile scanner with limited space needs for use and storage.

Majewski, Stanislaw (Yorktown, VA); Proffitt, James (Newport News, VA)

2011-02-08T23:59:59.000Z

391

Hot subdwarfs - Small stars marking important events in stellar evolution  

E-Print Network [OSTI]

Hot subdwarfs are considered to be the compact helium cores of red giants, which lost almost their entire hydrogen envelope. What causes this enormous mass loss is still unclear. Binary interactions are invoked and a significant fraction of the hot subdwarf population is indeed found in close binaries. In a large project we search for the close binary sdBs with the most and the least massive companions. Significantly enhancing the known sample of close binary sdBs we performed the first comprehensive study of this population. Triggered by the discovery of two sdB binaries with close brown dwarf companions in the course of this project, we were able to show that the interaction of stars with substellar companions is an important channel to form sdB stars. Finally, we discovered a unique and very compact binary system consisting of an sdB and a massive white dwarf, which qualifies as progenitor candidate for a supernova type Ia. In addition to that, we could connect those explosions to the class of hypervelocit...

Geier, S

2015-01-01T23:59:59.000Z

392

Compact gas-insulated transformer. Fourteenth quarterly report  

SciTech Connect (OSTI)

Objective is to develop a compact, more efficient, quieter transformer which does not rely on mineral oil insulation. Compressed SF/sub 6/ is used as the external insulation and polymer film as the insulation between turns. A separate liquid cooling system is also provided. This document reports progress made in design, mechanical, dielectric, short circuit, thermal, materials, prototype, accessories, commercialization, and system studies. (DLC)

Not Available

1983-08-01T23:59:59.000Z

393

Compact Refractive Imaging Spectrometer Designs Utilizing Immersed Gratings  

DOE Patents [OSTI]

A compact imaging spectrometer comprising an entrance slit for directing light, a first means for receiving the light and focusing the light, an immersed diffraction grating that receives the light from the first means and defracts the light, a second means for receiving the light from the immersed diffraction grating and focusing the light, and an image plane that receives the light from the second means

Lerner, Scott A. (Livermore, CA); Bennett, Charles L. (Livermore, CA); Bixler, Jay V. (Oakland, CA); Kuzmenko, Paul J. (Livermore, CA); Lewis, Isabella T. (San Jose, CA)

2005-07-26T23:59:59.000Z

394

Microscopic analysis of irradiated AGR-1 coated particle fuel compacts  

SciTech Connect (OSTI)

The AGR-1 experiment involved irradiation of 72 TRISO-coated particle fuel compacts to a peak compact-average burnup of 19.5% FIMA with no in-pile failures observed out of 3 x 105 total particles. Irradiated AGR-1 fuel compacts have been cross-sectioned and analyzed with optical microscopy to characterize kernel, buffer, and coating behavior. Six compacts have been examined, spanning a range of irradiation conditions (burnup, fast fluence, and irradiation temperature) and including all four TRISO coating variations irradiated in the AGR-1 experiment. The cylindrical specimens were sectioned both transversely and longitudinally, then polished to expose from 36 to 79 individual particles near midplane on each mount. The analysis focused primarily on kernel swelling and porosity, buffer densification and fracturing, buffer–IPyC debonding, and fractures in the IPyC and SiC layers. Characteristic morphologies have been identified, 981 particles have been classified, and spatial distributions of particle types have been mapped. No significant spatial patterns were discovered in these cross sections. However, some trends were found between morphological types and certain behavioral aspects. Buffer fractures were found in 23% of the particles, and these fractures often resulted in unconstrained kernel protrusion into the open cavities. Fractured buffers and buffers that stayed bonded to IPyC layers appear related to larger pore size in kernels. Buffer–IPyC interface integrity evidently factored into initiation of rare IPyC fractures. Fractures through part of the SiC layer were found in only four classified particles, all in conjunction with IPyC–SiC debonding. Compiled results suggest that the deliberate coating fabrication variations influenced the frequencies of IPyC fractures and IPyC–SiC debonds.

Scott A. Ploger; Paul A. Demkowicz; John D. Hunn; Jay S. Kehn

2014-05-01T23:59:59.000Z

395

On a -ideal of compact sets Tamas Matrai,a  

E-Print Network [OSTI]

subsets of 2 and prove that it is not Tukey reducible to the ideal I1/n = {H : hH 1/h , Tukey reducibility 2000 MSC: 03E15, 54H05, 28A05 1. Complexity of -ideals of compact sets Let X". The notion of complexity we are concerned with in the present note is Tukey reducibility, i.e. the comparison

Mátrai, Tamás

396

Flaw-detection characteristics of the compact MIB-4 betatron  

SciTech Connect (OSTI)

The compact pulse betatron using electrons accelerated to an energy of up to 4 MeV (MIB-4) is designed for the radiographic inspection of reinforced-concrete structures and buildings, welded joints, various materials, and assemblies. Information which refines and complements the method of inspecting parts by means of the MIB-4 device is provided. The results obtained in testing this equipment abroad are given.

Boiko, D.A.; Filimonov, A.A.; Chakhlov, V.L.

1987-09-01T23:59:59.000Z

397

Compact betatron with four controlling-field periodicity elements  

SciTech Connect (OSTI)

A compact 3-MeV betatron is described. The electromagnet of the betatron uses removable four-element poles, which form a magnetic field with azimuthal variation. The betatron accelerates 2 x 10/sup 10/ particles per cycle. The cycle repetition frequency is up to 400 Hz. The radius of the equilibrium orbit is 4.5 cm. The maximum interpole gap is 4 cm. The depth of magnetic-field variation on the equilibrium radius is 0.15.

Chakhlov, V.L.; Pushin, V.S.; Burov, G.I.; Zvontsov, A.A.; Zvorygin, V.P.; Zrelov, Yu.D.

1987-01-01T23:59:59.000Z

398

Stability of thin-shell interfaces inside compact stars  

E-Print Network [OSTI]

We use the thin-shell Darmois-Israel formalism to model and assess the stability of the interfaces separating phases, e.g. the core and the crust, within compact stars. We exemplify the relevance and non-triviality of this treatment in the simplest case of an incompressible star, in constant pressure phase transitions, and in the case of strange quark stars with crust.

Jonas P. Pereira; Jaziel G. Coelho; Jorge A. Rueda

2015-01-05T23:59:59.000Z

399

Ship response using a compact wave spectrum model  

E-Print Network [OSTI]

characterization of the sea. The next step in determining and evaluating the response characteristics of a design ship rests in the ability to relate the wave energy spectrum to actual ship responses. Through detailed research of the ocean and based upon laws... to spectral width and spectral shape is also studied. The original and compacted wave data bases are then used to excite sets of ship response amplitude operator's (RAO's). The resulting response spectra are examined both statistically and for any...

Linn, Larry Donald

1985-01-01T23:59:59.000Z

400

PREPARED FOR THE U.S. DEPARTMENT OF ENERGY, UNDER CONTRACT DE-AC02-76CH03073  

E-Print Network [OSTI]

Heating Scenarios for the National Compact Stellarator Experiment R. Majeski, J.R. Wilson, and M in Calendar Year 2001. The home page for PPPL Reports and Publications is: http://www.pppl.gov/pub_report/ DOE: http://www.ntis.gov/ordering.htm #12;Mode Conversion Heating Scenarios for the National Compact

Note: This page contains sample records for the topic "national compact stellarator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

PREPARED FORTHE U.S. DEPARTMENT OF ENERGY, UNDER CONTRACT DEAC0276CH03073  

E-Print Network [OSTI]

Heating Scenarios National Compact Stellarator Experiment Majeski, J.R. Wilson, and Zarnstorff May 2001 Publications Reports web site Calendar Year 2001. The home PPPL Reports and Publications http­8547 Internet: http://www.ntis.gov/ordering.htm #12; Mode Conversion Heating Scenarios for the National Compact

402

Stellar models with mixing length and T(tau) relations calibrated on 3D convection simulations  

E-Print Network [OSTI]

(abridged) The calculation of the thermal stratification in the superadiabatic layers of stellar models with convective envelopes is a long standing problem of stellar astrophysics, and has a major impact on predicted observational properties like radius and effective temperature. The Mixing Length Theory, almost universally used to model the superadiabatic convective layers, contains effectively one free parameter to be calibrated --alpha(ml)-- whose value controls the resulting effective temperature. Here we present the first self-consistent stellar evolution models calculated by employing the atmospheric temperature stratification, Rosseland opacities, and calibrated variable alpha(ml) (dependent on effective temperature and surface gravity) from a large suite of three-dimensional radiation hydrodynamics simulations of stellar convective envelopes and atmospheres for solar stellar composition (Trampedach et al. 2013). From our calculations (with the same composition of the radiation hydrodynamics simulatio...

Salaris, Maurizio

2015-01-01T23:59:59.000Z

403

VALIDATION OF A THERMAL CONDUCTIVITY MEASUREMENT SYSTEM FOR FUEL COMPACTS  

SciTech Connect (OSTI)

A high temperature guarded-comparative-longitudinal heat flow measurement system has been built to measure the thermal conductivity of a composite nuclear fuel compact. It is a steady-state measurement device designed to operate over a temperature range of 300 K to 1200 K. No existing apparatus is currently available for obtaining the thermal conductivity of the composite fuel in a non-destructive manner due to the compact’s unique geometry and composite nature. The current system design has been adapted from ASTM E 1225. As a way to simplify the design and operation of the system, it uses a unique radiative heat sink to conduct heat away from the sample column. A finite element analysis was performed on the measurement system to analyze the associated error for various operating conditions. Optimal operational conditions have been discovered through this analysis and results are presented. Several materials have been measured by the system and results are presented for stainless steel 304, inconel 625, and 99.95% pure iron covering a range of thermal conductivities of 10 W/m*K to 70 W/m*K. A comparison of the results has been made to data from existing literature.

Jeff Phillips; Colby Jensen; Changhu Xing; Heng Ban

2011-03-01T23:59:59.000Z

404

Tracer diffusion in compacted, water-saturated bentonite  

SciTech Connect (OSTI)

Compacted Na-bentonite clay barriers, widely used in theisolation of solid-waste landfills and other contaminated sites, havebeen proposed for a similar use in the disposal of high-level radioactivewaste. Molecular diffusion through the pore space in these barriers playsa key role in their performance, thus motivating recent measurements ofthe apparent diffusion coefficient tensor of water tracers in compacted,water-saturated Na-bentonites. In the present study, we introduce aconceptual model in which the pore space of water-saturated bentonite isdivided into 'macropore' and 'interlayer nanopore' compartments. Withthis model we determine quantitatively the relative contributions ofpore-network geometry (expressed as a geometric factor) and of thediffusive behavior of water molecules near montmorillonite basal surfaces(expressed as a contristivity factor) to the apparent diffusioncoefficient tensor. Our model predicts, in agreement with experiment,that the mean principal value of the apparent diffusion coefficienttensor follows a single relationship when plotted against the partialmontmorillonite dry density (mass of montmorillonite per combined volumeof montmorillonite and pore space). Using a single fitted parameter, themean principal geometric factor, our model successfully describes thisrelationship for a broad range of bentonite-water system, from dilute gelto highly-compacted bentonite with 80 percent of its pore water ininterlayer nanopores.

Bourg, Ian C.; Sposito, Garrison; Bourg, Alain C.M.

2005-08-04T23:59:59.000Z

405

Time machines with the compactly determined Cauchy horizon  

E-Print Network [OSTI]

The building of a time machine, if possible at all, requires the relevant regions of spacetime to be compact (that is, physically speaking, free from sources of unpredictability such as infinities and singularities). Motivated by this argument we consider the spacetimes with the compactly determined Cauchy horizons (CDCHs), the defining property of which is the compactness of $\\overline{J^-(\\EuScript U)}\\cap J^+(\\EuScript S_0)$, where $\\EuScript U$ is an open subset of the Cauchy horizon and $\\EuScript S_0$ is a Cauchy surface of the initial globally hyperbolic region $\\ingh$. The following two facts are established: 1) $\\ingh$ has no globally hyperbolic maximal extension. This means that by shaping appropriately a precompact portion of a globally hyperbolic region one can \\emph{force} the Universe to produce either a closed causal curve, or a quasiregular singularity, whichever it abhors less; 2) Before a CDCH is formed a null geodesic appears which infinitely approaches the horizon returning again and again in the same --- arbitrarily small --- region. The energy of the photon moving on such a geodesic increases with each passage, or at least falls insufficiently fast. As a result, an observer located in the mentioned region would see a bunch of photons passing through his laboratory with the arbitrarily large total energy. We speculate that this phenomenon may have observable consequences.

S. Krasnikov

2014-08-01T23:59:59.000Z

406

Ultra-Compact High-Efficiency Luminaire for General Illumination  

SciTech Connect (OSTI)

Cree has developed a new ultra-compact light emitting diode (LED) luminaire capable of providing high efficacy with excellent color quality that can lead to significant energy savings in todayâ??s commercial and retail applications. This success was based on an integrated development effort tailoring the LED component characteristics, optics, thermal management and driver design for the small footprint to achieve an overall system efficiency of â?¥ 70%. A new LED component was designed to provide high brightness and efficacy in a form factor that allowed for a small directional beam with a luminaire housing design able to dissipate the heat effectively using a small physical envelope. A very compact, 90% efficient driver was developed to meet the system performance while not taking away any thermal mass from the heat sink. A 91% efficient secondary optics was designed to maximize efficiency while providing a smooth beam. The reliability of the new LED component was robust under accelerated testing conditions. Luminaires were assembled integrating the novel LED component, secondary optics, heat sink and driver technology to demonstrate the system improvement. Cree has successfully completed this project by developing an ultra-compact LED luminaire that provided 380 lumens at a correlated color temperature (CCT) of 2822 K and color rendering index (CRI) of 94 with an efficacy of 94 lumens per watt (LPW) when operating at 4 W input power (steady state) with an overall system efficiency of 81%. At a higher input power of 9 Watts, the lamp provided 658 lumens at 71 LPW.

Ted Lowes

2012-04-08T23:59:59.000Z

407

The Transition between Star Clusters and Dwarf Galaxies -- On the existence of a mass-radius relation for star clusters of masses >10^7 Mo: are these objects formed in mergers of stellar systems?  

E-Print Network [OSTI]

At which masses does the regime of globular clusters end and the one of dwarf galaxies begin? And what separates these two classes of hot stellar systems? We examine to what extend very massive (>10^7 Mo) young star clusters are similar to their lower mass counter parts and to which degree they resemble other objects in their mass regime (dwarf--globular transition objects (DGTOs), ultra compact dwarf galaxies (UCDs), galaxy nuclei). The comparison is performed by placing the recently observed very massive young clusters onto known scaling relation defined by globular clusters (with typical masses 10^{6.5-7} Mo) young clusters seem to show a mass--radius relation compatible with the one defined by hot stellar systems of galaxy mass. This, in turn, can explain their location on the other scaling relations investigated. It contrasts with the behaviour of the less massive young clusters and of globular clusters, which do not exhibit any mass-radius relation. However, the behaviour of the most massive clusters is similar to that of most other objects in that mass regime (10^6-10^8 Mo). We show that the properties of young massive clusters are compatible with other objects in the same mass regime such as DGTOs/UCDs. They present a possible direct avenue of formation for those objects, which does not require the transformation of a previously existing stellar system. Simulations and observations support the possibility of the formation of such very massive young clusters by early mergers of lower mass stellar clusters, which could explain the emergence of a mass--radius relation.

Markus Kissler-Patig; Andres Jordan; Nate Bastian

2005-12-14T23:59:59.000Z

408

Meridional Circulation in Solar and Stellar Convection Zones  

E-Print Network [OSTI]

We present a series of 3-D nonlinear simulations of solar-like convection, carried out using the Anelastic Spherical Harmonic (ASH) code, that are designed to isolate those processes that drive and shape meridional circulations within stellar convection zones. These simulations have been constructed so as to span the transition between solar-like differential rotation (fast equator/slow poles) and ``anti-solar' differential rotation (slow equator/fast poles). Solar-like states of differential rotation, arising when convection is rotationally constrained, are characterized by a very different convective Reynolds stress than anti-solar regimes, wherein convection only weakly senses the Coriolis force. We find that the angular momentum transport by convective Reynolds stress plays a central role in establishing the meridional flow profiles in these simulations. We find that the transition from single-celled to multi-celled meridional circulation profiles in strong and weak regimes of rotational constraint is lin...

Featherstone, Nicholas A

2015-01-01T23:59:59.000Z

409

The Solar Heavy Element Abundances: I. Constraints from Stellar Interiors  

E-Print Network [OSTI]

The latest solar atmosphere models include non-LTE corrections and 3D hydrodynamic convection simulations. These models predict a significant reduction in the solar metal abundance, which leads to a serious conflict between helioseismic data and the predictions of solar interiors models. We demonstrate that the helioseismic constraints on the surface convection zone depth and helium abundance combined with stellar interiors models can be used to define the goodness of fit for a given chemical composition. After a detailed examination of the errors in the theoretical models we conclude that models constructed with the older solar abundances are consistent (seismic data. Models constructed with the proposed new low abundance scale are strongly disfavored, disagreeing at the 15 \\sigma level. We then use the sensitivity of the seismic properties to abundance changes to invert the problem and infer a seismic solar heavy element abundance mix with two components: meteoritic abundances, and th...

Delahaye, F; Delahaye, Franck; Pinsonneault, Marc

2005-01-01T23:59:59.000Z

410

Carbon-poor stellar cores as supernova progenitors  

E-Print Network [OSTI]

Exploring stellar models which ignite carbon off-center (in the mass range of about 1.05 - 1.25 Msun, depending on the carbon mass fraction) we find that they may present an interesting SN I progenitor scenario, since whereas in the standard scenario runaway always takes place at the same density of about 2 X 10^9 gr/cm^3, in our case, due to the small amount of carbon ignited, we get a whole range of densities from 1 X 10^9 up to 6 X 10^9 gr/cm^3. These results could contribute in resolving the emerging recognition that at least some diversity among SNe I exists, since runaway at various central densities is expected to yield various outcomes in terms of the velocities and composition of the ejecta, which should be modeled and compared to observations.

Roni Waldman; Zalman Barkat

2007-04-16T23:59:59.000Z

411

Microlensing Detections of Planets in Binary Stellar Systems  

E-Print Network [OSTI]

We demonstrate that microlensing can be used for detecting planets in binary stellar systems. This is possible because in the geometry of planetary binary systems where the planet orbits one of the binary component and the other binary star is located at a large distance, both planet and secondary companion produce perturbations at a common region around the planet-hosting binary star and thus the signatures of both planet and binary companion can be detected in the light curves of high-magnification lensing events. We find that identifying planets in binary systems is optimized when the secondary is located in a certain range which depends on the type of the planet. The proposed method can detect planets with masses down to one tenth of the Jupiter mass in binaries with separations planet mass and binary separation are not covered by other methods and thus microlensing would be able to make the planetary binary sample richer.

Dong-Wook Lee; Chung-Uk Lee; Byeong-Gon Park; Sun-Ju Chung; Young-Soo Kim; Ho-Il Kim; Cheongho Han

2007-09-13T23:59:59.000Z

412

Mechanical Feedback: From stellar wind bubbles to starbursts  

E-Print Network [OSTI]

The current understanding of mechanical feedback is reviewed by evaluating the standard, adiabatic model for shell formation and evolution. This model is relevant to phenomena ranging from individual stellar-wind bubbles to galactic superwinds, forming the basis for our understanding of the multiphase ISM, IGM, and galactic evolutionary processes. Although significant discrepancies between the model and observation have been identified, to date there are none that require a fundamental revision. A variety of evidence, ranging over three orders of magnitude in spatial scale, is broadly consistent with the standard model. This includes kinematics of individual objects, observations of hot gas, the size distribution of HI shells, and outflow rates from starburst galaxies. However, some of the most pressing issues relating to shell evolution are still outstanding and obstruct efforts to resolve key questions like the fate of the hot gas.

M. S. Oey; C. J. Clarke; P. Massey

2001-03-20T23:59:59.000Z

413

A DYNAMICAL SIGNATURE OF MULTIPLE STELLAR POPULATIONS IN 47 TUCANAE  

SciTech Connect (OSTI)

Based on the width of its main sequence, and an actual observed split when viewed through particular filters, it is widely accepted that 47 Tucanae contains multiple stellar populations. In this contribution, we divide the main sequence of 47 Tuc into four color groups, which presumably represent stars of various chemical compositions. The kinematic properties of each of these groups are explored via proper motions, and a strong signal emerges of differing proper-motion anisotropies with differing main-sequence color; the bluest main-sequence stars exhibit the largest proper-motion anisotropy which becomes undetectable for the reddest stars. In addition, the bluest stars are also the most centrally concentrated. A similar analysis for Small Magellanic Cloud stars, which are located in the background of 47 Tuc on our frames, yields none of the anisotropy exhibited by the 47 Tuc stars. We discuss implications of these results for possible formation scenarios of the various populations.

Richer, Harvey B.; Heyl, Jeremy [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1 (Canada); Anderson, Jay; Kalirai, Jason S. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Shara, Michael M. [Department of Astrophysics, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024 (United States); Dotter, Aaron [Research School of Astronomy and Astrophysics, Australian National University, Weston, ACT 2611 (Australia); Fahlman, Gregory G. [National Research Council, Herzberg Institute of Astrophysics, Victoria, BC V9E 2E7 (Canada); Rich, R. Michael, E-mail: richer@astro.ubc.ca, E-mail: heyl@phas.ubc.ca, E-mail: jayander@stsci.edu, E-mail: jkalarai@stsci.edu, E-mail: mshara@amnh.org, E-mail: aaron.dotter@gmail.com, E-mail: greg.fahlman@nrc-cnrc.gc.ca, E-mail: rmr@astro.ucla.edu [Division of Astronomy and Astrophysics, University of California at Los Angeles, Los Angeles, CA 90095 (United States)

2013-07-01T23:59:59.000Z

414

MID-INFRARED SPECTRAL VARIABILITY ATLAS OF YOUNG STELLAR OBJECTS  

SciTech Connect (OSTI)

Optical and near-infrared variability is a well-known property of young stellar objects. However, a growing number of recent studies claim that a considerable fraction of them also exhibit mid-infrared flux changes. With the aim of studying and interpreting variability on a decadal timescale, here we present a mid-infrared spectral atlas containing observations of 68 low- and intermediate-mass young stellar objects. The atlas consists of 2.5-11.6 {mu}m low-resolution spectra obtained with the ISOPHOT-S instrument on board the Infrared Space Observatory (ISO) between 1996 and 1998, as well as 5.2-14.5 {mu}m low-resolution spectra obtained with the Infrared Spectrograph instrument on board the Spitzer Space Telescope between 2004 and 2007. The observations were retrieved from the ISO and Spitzer archives and were post-processed interactively by our own routines. For those 47 objects where multi-epoch spectra were available, we analyze mid-infrared spectral variability on annual and/or decadal timescales. We identify 37 variable candidate sources. Many stars show wavelength-independent flux changes, possibly due to variable accretion rates. In several systems, all exhibiting 10 {mu}m silicate emission, the variability of the 6-8 {mu}m continuum, and the silicate feature exhibit different amplitudes. A possible explanation is variable shadowing of the silicate-emitting region by an inner disk structure of changing height or extra silicate emission from dust clouds in the disk atmosphere. Our results suggest that mid-infrared variability, in particular, the wavelength-dependent changes, is more ubiquitous than was known before. Interpreting this variability is a new possibility for exploring the structure of the disk and its dynamical processes.

Kospal, A. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA, Leiden (Netherlands); Abraham, P.; Kun, M.; Moor, A. [Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, P.O. Box 67, 1525 Budapest (Hungary); Acosta-Pulido, J. A. [Instituto de Astrofisica de Canarias, Via Lactea s/n, 38200 La Laguna, Tenerife (Spain); Dullemond, C. P. [Institut fuer Theoretische Astrophysik, Zentrum fuer Astronomie der Universitaet Heidelberg, Albert-Ueberle-Str. 2, 69120 Heidelberg (Germany); Henning, Th.; Leinert, Ch. [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, 69117 Heidelberg (Germany); Turner, N. J., E-mail: akospal@rssd.esa.int [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

2012-08-01T23:59:59.000Z

415

Argonne National Laboratory's Nondestructive  

E-Print Network [OSTI]

Argonne National Laboratory's Nondestructive Evaluation Technologies NDE #12;Over45yearsexperienceinNondestructiveEvaluation... Argonne National Laboratory's world-renowned researchers have a proven the safe operationof advanced nuclear reactors. Argonne's World-Class Nondestructive Evaluation

Kemner, Ken

416

Computational geomechanics & applications at Sandia National Laboratories.  

SciTech Connect (OSTI)

Sandia National Laboratories (SNL) is a multi-program national laboratory in the business of national security, whose primary mission is nuclear weapons (NW). It is a prime contractor to the USDOE, operating under the NNSA and is one of the three NW national laboratories. It has a long history of involvement in the area of geomechanics, starting with the some of the earliest weapons tests at Nevada. Projects in which geomechanics support (in general) and computational geomechanics support (in particular) are at the forefront at Sandia, range from those associated with civilian programs to those in the defense programs. SNL has had significant involvement and participation in the Waste Isolation Pilot Plant (low-level defense nuclear waste), the Yucca Mountain Project (formerly proposed for commercial spent fuel and high-level nuclear waste), and the Strategic Petroleum Reserve (the nation's emergency petroleum store). In addition, numerous industrial partners seek-out our computational/geomechanics expertise, and there are efforts in compressed air and natural gas storage, as well as in CO{sub 2} Sequestration. Likewise, there have also been collaborative past efforts in the areas of compactable reservoir response, the response of salt structures associated with reservoirs, and basin modeling for the Oil & Gas industry. There are also efforts on the defense front, ranging from assessment of vulnerability of infrastructure to defeat of hardened targets, which require an understanding and application of computational geomechanics. Several examples from some of these areas will be described and discussed to give the audience a flavor of the type of work currently being performed at Sandia in the general area of geomechanics.

Arguello, Jose Guadalupe, Jr.

2010-04-01T23:59:59.000Z

417

A Leadership-Class U.S. Domestic Stellarator Program Hutch Neilson, David Gates, and Michael Zarnstorff  

E-Print Network [OSTI]

concepts or because they lack the core capabilities for it. U.S. leadership in QS stellarators is both attractiveness as a partner is based on our core stellarator physics and engineering capabilities, a product of DOE investment in stellarator research over many years. We can remain active participants

418

National Nuclear Security Administration  

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

FROM: SUBJECT: USIUK Memorandum of Understanding between National Nuclear Security Administration's (NNSA) Associate Administrator for Defense Nuclear Security (AADNS)...

419

National Hydropower Map  

Broader source: Energy.gov [DOE]

High-resolution map produced by Oak Ridge National Laboratory showing hydropower resources throughout the United States.

420

National Nuclear Security Administration Los Alamos National  

National Nuclear Security Administration (NNSA)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "ofEarlyEnergyDepartmentNational Nuclearhas 'Natitude' | NationalADR services are contractedLawrence National

Note: This page contains sample records for the topic "national compact stellarator" from the National Library of EnergyBeta (NLEBeta).
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421

National Supplemental Screening Program | Argonne National Laboratory  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the Contributions andDataNational Library of Energy LoginofNationalLos(SC)National

422

NATIONAL HYDROGEN ENERGY ROADMAP  

E-Print Network [OSTI]

NATIONAL HYDROGEN ENERGY ROADMAP NATIONAL HYDROGEN ENERGY ROADMAP . . Toward a More Secure and Cleaner Energy Future for America Based on the results of the National Hydrogen Energy Roadmap Workshop to make it a reality. This Roadmap provides a framework that can make a hydrogen economy a reality

423

The Hazards of Use and Disposal of Compact Fluorescent Bulbs Compact fluorescent lights (aka. CFLs) work by exciting a phosphorous coating within the tube to emit  

E-Print Network [OSTI]

The Hazards of Use and Disposal of Compact Fluorescent Bulbs Compact fluorescent lights (aka. CFLs FLUORESCENT BULB? Because there is such a small amount of mercury in CFLs, the greatest hazard exposure the bulb to be an efficient light source. By comparison, older home thermometers contain 500 milligrams

Maroncelli, Mark

424

Brookhaven National Laboratory National Synchrotron Light Source  

E-Print Network [OSTI]

CHARACTERISTICS Laser Type (Argon, CO2, etc) Wavelengths ANSI Class Maximum Power of Energy/Pulse Pulse Length. American National Standards Institute (ANSI) Standard for Safe Use of Lasers; (ANSI Z136.1-2000) Laser

Ohta, Shigemi

425

The impact of alpha/Fe enhanced stellar evolutionary tracks on the ages of elliptical galaxies  

E-Print Network [OSTI]

We complement our study of alpha/Fe enhanced stellar population models of Lick absorption indices (Thomas et al. 2003) by comparing two sets of alpha/Fe enhanced models. In both models the impact on Lick indices due to alpha/Fe enhancement is accounted for through a modification of the stellar absorption line-strengths using the response functions of Tripicco & Bell (1995). One set of models, however, uses solar-scaled, the other alpha/Fe enhanced stellar evolutionary tracks. Since the alpha/Fe enhanced tracks are hotter than the solar-scaled ones (Salasnich et al. 2000), the correspondent stellar population models have slightly weaker metallic indices (i.e. Mgb, etc.) and stronger Balmer line indices (Hbeta) (Maraston et al 2003). Here we explore quantitatively the impact of this effect on the alpha/Fe ratios, metallicities and ages that are derived for elliptical galaxies. We find that the modest decrease of the metallic indices Mgb and balance each other, such that fully consistent alpha/Fe ratios are derived for stellar systems using alpha/Fe enhanced models with either solar-scaled or alpha/Fe enhanced stellar tracks. The decrease of the metallic indices and the increase of Hbeta conspire in a way that also consistent metallicities are obtained. The derived ages, instead, are significantly different. The inclusion of alpha/Fe enhanced stellar tracks leads to the derivation of ages as high as 30 Gyr for elliptical galaxies. For the same objects, ages not older than 15 Gyr are obtained, if alpha/Fe enhanced models using solar-scaled tracks are adopted. This may indicate that current stellar evolutionary models overestimate the bluing of stellar evolutionary tracks due to alpha/Fe enhanced chemical mixtures at super-solar metallicities.

Daniel Thomas; Claudia Maraston

2003-02-04T23:59:59.000Z

426

Preliminary results of post-irradiation examination of the AGR-1 TRISO fuel compacts  

SciTech Connect (OSTI)

Five irradiated fuel compacts from the AGR-1 experiment have been examined in detail in order to assess in-pile fission product release behavior. Compacts were electrolytically deconsolidated and analyzed using the leach-burn-leach technique to measure fission product inventory in the compact matrix and identify any particles with a defective SiC layer. Loose particles were then gamma counted to measure the fission product inventory. One particle with a defective SiC layer was found in the five compacts examined. The fractional release of Ag 110m from the particles was significant. The total fraction of silver released from all the particles within a compact ranged from 0-0.63 and individual particles within a single compact often exhibited a very wide range of silver release. The average fractional release of Eu-154 from all particles in a compact was 2.4×10-4—1.3×10-2, which is indicative of release through intact coatings. The fractional Cs-134 inventory in the compact matrix was <2×10-5 when all coatings remained intact, indicating good cesium retention. Approximately 1% of the palladium inventory was found in the compact matrix for two of the compacts, indicating significant release through intact coatings.

Paul Demkowicz; John Hunn; Robert Morris; Jason Harp; Philip Winston; Charles Baldwin; Fred Montgomery; Scott Ploger; Isabella van Rooyen

2012-10-01T23:59:59.000Z

427

Model stars for the modelling of galaxies: $?$-enhancement in stellar populations models  

E-Print Network [OSTI]

Stellar population (SP) models are an essential tool to understand the observations of galaxies and clusters. One of the main ingredients of a SP model is a library of stellar spectra, and both empirical and theoretical libraries can been used for this purpose. Here I will start by giving a short overview of the pros and cons of using theoretical libraries, i.e. model stars, to produce our galaxy models. Then I will address the question on how theoretical libraries can be used to model stellar populations, in particular to explore the effect of $\\alpha$-enhancement on spectral observables.

P. Coelho

2008-02-19T23:59:59.000Z

428

On the Piecewise Parabolic Method for Compressible Flow with Stellar Equations of State  

E-Print Network [OSTI]

The piecewise parabolic method and related schemes are widely used to model stellar flows. Several different methods for extending the validity of these methods to a general equation of state have been proposed over time, but direct comparisons amongst one-another and exact solutions with stellar equations of state are not widely available. We introduce some simple test problems with exact solutions run with a popular stellar equation of state and test how two existing codes with different approaches to incorporating general gases perform. The source code for generating the exact solutions is made available.

Zingale, M

2015-01-01T23:59:59.000Z

429

Microscopic analysis of irradiated AGR-1 coated particle fuel compacts  

SciTech Connect (OSTI)

The AGR-1 experiment involved irradiation of 72 TRISO-coated particle fuel compacts to a peak burnup of 19.5% FIMA with no in-pile failures observed out of 3×105 total particles. Irradiated AGR-1 fuel compacts have been cross-sectioned and analyzed with optical microscopy to characterize kernel, buffer, and coating behavior. Five compacts have been examined so far, spanning a range of irradiation conditions (burnup, fast fluence, and irradiation temperature) and including all four TRISO coating variations irradiated in the AGR-1 experiment. The cylindrical specimens were sectioned both transversely and longitudinally, then polished to expose between approximately 40-80 individual particles on each mount. The analysis focused primarily on kernel swelling and porosity, buffer densification and fracturing, buffer-IPyC debonding, and fractures in the IPyC and SiC layers. Characteristic morphologies have been identified, over 800 particles have been classified, and spatial distributions of particle types have been mapped. No significant spatial patterns were discovered in these cross sections. However, some trends were found between morphological types and certain behavioral aspects. Buffer fractures were found in approximately 23% of the particles, and these fractures often resulted in unconstrained kernel swelling into the open cavities. Fractured buffers and buffers that stayed bonded to IPyC layers appear related to larger pore size in kernels. Buffer-IPyC interface integrity evidently factored into initiation of rare IPyC fractures. Fractures through part of the SiC layer were found in only three particles, all in conjunction with IPyC-SiC debonding. Compiled results suggest that the deliberate coating fabrication variations influenced the frequencies of IPyC fractures, IPyC-SiC debonds, and SiC fractures.

Scott Ploger; Paul Demkowicz; John Hunn; Robert Morris

2012-10-01T23:59:59.000Z

430

COMPACT BINARY PROGENITORS OF SHORT GAMMA-RAY BURSTS  

SciTech Connect (OSTI)

In recent years, detailed observations and accurate numerical simulations have provided support to the idea that mergers of compact binaries containing either two neutron stars (NSs) or an NS and a black hole (BH) may constitute the central engine of short gamma-ray bursts (SGRBs). The merger of such compact binaries is expected to lead to the production of a spinning BH surrounded by an accreting torus. Several mechanisms can extract energy from this system and power the SGRBs. Here we connect observations and numerical simulations of compact binary mergers, and use the current sample of SGRBs with measured energies to constrain the mass of their powering tori. By comparing the masses of the tori with the results of fully general-relativistic simulations, we are able to infer the properties of the binary progenitors that yield SGRBs. By assuming a constant efficiency in converting torus mass into jet energy, {epsilon}{sub jet} = 10%, we find that most of the tori have masses smaller than 0.01 M{sub Sun }, favoring 'high-mass' binary NSs mergers, i.e., binaries with total masses {approx}> 1.5 the maximum mass of an isolated NS. This has important consequences for the gravitational wave signals that may be detected in association with SGRBs, since 'high-mass' systems do not form a long-lived hypermassive NS after the merger. While NS-BH systems cannot be excluded to be the engine of at least some of the SGRBs, the BH would need to have an initial spin of {approx}0.9 or higher.

Giacomazzo, Bruno [JILA, University of Colorado and National Institute of Standards and Technology, Boulder, CO 80309 (United States); Perna, Rosalba [JILA and Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80309 (United States); Rezzolla, Luciano [Max-Planck-Institut fuer Gravitationsphysik, Albert-Einstein-Institut, Potsdam D-14476 (Germany); Troja, Eleonora [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Lazzati, Davide [Department of Physics, NC State University, 2401 Stinson Drive, Raleigh, NC 27695-8202 (United States)

2013-01-10T23:59:59.000Z

431

Controlled powder morphology experiments in megabar 304 stainless steel compaction  

SciTech Connect (OSTI)

Experiments with controlled morphology including shape, size, and size distribution were made on 304L stainless steel powders. These experiments involved not only the powder variables but pressure variables of 0.08 to 1.0 Mbar. Also included are measured container strain on the material ranging from 1.5% to 26%. Using a new strain controllable design it was possible to seperate and control, independently, strain and pressure. Results indicate that powder morphology, size distribution, packing density are among the pertinent parameters in predicting compaction of these powders.

Staudhammer, K.P.; Johnson, K.A.

1985-01-01T23:59:59.000Z

432

Diffusion Welding of Compact Heat Exchangers for Nuclear Applications  

SciTech Connect (OSTI)

The next-­-generation nuclear plant (NGNP) is designed to be a flexible source of energy, producing various mixes of electrical energy and process heat (for example, for hydrogen generation) on demand. Compact heat exchangers provide an attractive way to move energy from the helium primary reactor coolant to process heat uses. For process heat efficiency, reactor outlet temperatures of 750-­-900°C are desirable. There are minor but deleterious components in the primary coolant; the number of alloys that can handle this environment is small. The present work concentrates on Alloys 800H and 617.

Denis Clark; Ron Mizia; Dr. Michael V. Glazoff; Mr. Michael W. Patterson

2012-06-01T23:59:59.000Z

433

Compact cyclone filter train for radiological and hazardous environments  

DOE Patents [OSTI]

A compact cyclone filter train for the removal of hazardous and radiologi particles from a gaseous fluid medium which permits a small cyclone separator to be used in a very small space envelope due to the arrangement of the filter housing adjacent to the separator with the cyclone separator and the filters mounted on a plate. The entire unit will have a hoist connection at the center of gravity so that the entire unit including the separator, the filters, and the base can be lifted and repositioned as desired.

Bench, Thomas R. (Pittsburgh, PA)

1998-01-01T23:59:59.000Z

434

Compact cyclone filter train for radiological and hazardous environments  

DOE Patents [OSTI]

A compact cyclone filter train is disclosed for the removal of hazardous and radiological particles from a gaseous fluid medium. This filter train permits a small cyclone separator to be used in a very small space envelope due to the arrangement of the filter housing adjacent to the separator with the cyclone separator and the filters mounted on a plate. The entire unit will have a hoist connection at the center of gravity so that the entire unit including the separator, the filters, and the base can be lifted and repositioned as desired. 3 figs.

Bench, T.R.

1998-04-28T23:59:59.000Z

435

Compact high resolution isobar separator for study of exotic decays  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation Proposed New SubstationCleanCommunity Involvement and Making aCompact soft

436

A compact micro-wave synthesizer for transportable cold-atom interferometers  

SciTech Connect (OSTI)

We present the realization of a compact micro-wave frequency synthesizer for an atom interferometer based on stimulated Raman transitions, applied to transportable inertial sensing. Our set-up is intended to address the hyperfine transitions of {sup 87}Rb at 6.8 GHz. The prototype is evaluated both in the time and the frequency domain by comparison with state-of-the-art frequency references developed at Laboratoire national de métrologie et d'essais?Systémes de référence temps espace (LNE-SYRTE). In free-running mode, it features a residual phase noise level of ?65 dB rad{sup 2} Hz{sup ?1} at 10 Hz offset frequency and a white phase noise level in the order of ?120 dB rad{sup 2} Hz{sup ?1} for Fourier frequencies above 10 kHz. The phase noise effect on the sensitivity of the atomic interferometer is evaluated for diverse values of cycling time, interrogation time, and Raman pulse duration. To our knowledge, the resulting contribution is well below the sensitivity of any demonstrated cold atom inertial sensors based on stimulated Raman transitions. The drastic improvement in terms of size, simplicity, and power consumption paves the way towards field and mobile operations.

Lautier, J.; Lours, M.; Landragin, A., E-mail: arnaud.landragin@obspm.fr [LNE-SYRTE, Observatoire de Paris, CNRS, UPMC, 61 avenue de l’Observatoire, 75014 Paris (France)

2014-06-15T23:59:59.000Z

437

Advanced Alloys for Compact, High-Efficiency, High-Temperature Heat-Exchangers  

SciTech Connect (OSTI)

Oak Ridge National Laboratory (ORNL) has conducted research and development for several years which has been focused on the behavior and performance improvements of sheets and foils of various alloys for compact heat-exchangers (recuperators) for advanced microturbines. The performance and reliability of such thin sections are challenged at 650-750 C by fine grain size causing excessive creep, and by moisture effects greatly enhancing oxidation attack in exhaust gas environments. Standard 347 stainless steel has been used successfully at or below 600 C, but has suffered from both of these kinds of degradation at 650 C and above. Alloys have been identified which can have very good properties for such heat-exchangers, especially with careful control of microstructure during processing, including alloy 625, HR120 and the new AL20-25+Nb. These alloys, and the mechanistic understanding behind their behavior, are also applicable to achieving the better heat-exchanger technology needed for fuel cells or other high-temperature, clean-energy applications.

Maziasz, Philip J [ORNL; Pint, Bruce A [ORNL; Shingledecker, John P [ORNL; Evans, Neal D [ORNL; Yamamoto, Yukinori [ORNL; More, Karren Leslie [ORNL; Lara-Curzio, Edgar [ORNL

2006-01-01T23:59:59.000Z

438

Neutron Catalysis of Resonance Fusion in Stellar Matter  

E-Print Network [OSTI]

Within the framework of resonance fusion study in stellar matter the features of system consisted of two alpha particles and one neutron have been investigated at astrophysical energies. Consideration of three body scattering has been carried out on base of well-known Faddeev's equations. It is found that under certain conditions the series of resonance states appear in this system at very low energies. The lifetimes of these three body resonances are close to the lifetime of unstable nucleus 8Be. The simple forms of two body repulsive potentials are taken into account to describe the parameters of the alpha, alpha resonance and to satisfy n, alpha scattering data at very low energies. The explanation of resonance phenomena in n, alpha, alpha system is offered on base of physical model. The effect results from resonance quantum phenomena in few body dynamics. In turn, the resonance fusion can give influence on many astrophysical phenomena. The possibility of catalyzing this new mode of fusion by free neutrons in alpha particle matter is considered too.

Nurgali Takibayev

2005-08-22T23:59:59.000Z

439

Stellar Winds on the Main-Sequence I: Wind Model  

E-Print Network [OSTI]

Aims: We develop a method for estimating the properties of stellar winds for low-mass main-sequence stars between masses of 0.4 and 1.1 solar masses at a range of distances from the star. Methods: We use 1D thermal pressure driven hydrodynamic wind models run using the Versatile Advection Code. Using in situ measurements of the solar wind, we produce models for the slow and fast components of the solar wind. We consider two radically different methods for scaling the base temperature of the wind to other stars: in Model A, we assume that wind temperatures are fundamentally linked to coronal temperatures, and in Model B, we assume that the sound speed at the base of the wind is a fixed fraction of the escape velocity. In Paper II of this series, we use observationally constrained rotational evolution models to derive wind mass loss rates. Results: Our model for the solar wind provides an excellent description of the real solar wind far from the solar surface, but is unrealistic within the solar corona. We run ...

Johnstone, C P; Lüftinger, T; Toth, G; Brott, I

2015-01-01T23:59:59.000Z

440

PHAT Stellar Cluster Survey. II. Andromeda Project Cluster Catalog  

E-Print Network [OSTI]

We construct a stellar cluster catalog for the Panchromatic Hubble Andromeda Treasury (PHAT) survey using image classifications collected from the Andromeda Project citizen science website. We identify 2,753 clusters and 2,270 background galaxies within ~0.5 deg$^2$ of PHAT imaging searched, or ~400 kpc$^2$ in deprojected area at the distance of the Andromeda galaxy (M31). These identifications result from 1.82 million classifications of ~20,000 individual images (totaling ~7 gigapixels) by tens of thousands of volunteers. We show that our crowd-sourced approach, which collects >80 classifications per image, provides a robust, repeatable method of cluster identification. The high spatial resolution Hubble Space Telescope images resolve individual stars in each cluster and are instrumental in the factor of ~6 increase in the number of clusters known within the survey footprint. We measure integrated photometry in six filter passbands, ranging from the near-UV to the near-IR. PHAT clusters span a range of ~8 ma...

Johnson, L Clifton; Dalcanton, Julianne J; Wallace, Matthew L; Simpson, Robert J; Lintott, Chris J; Kapadia, Amit; Skillman, Evan D; Caldwell, Nelson; Fouesneau, Morgan; Weisz, Daniel R; Williams, Benjamin F; Beerman, Lori C; Gouliermis, Dimitrios A; Sarajedini, Ata

2015-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "national compact stellarator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Herschel Hi-GAL imaging of massive young stellar objects  

E-Print Network [OSTI]

We used Herschel Hi-GAL survey data to determine whether massive young stellar objects (MYSOs) are resolved at 70$\\mu$m and to study their envelope density distribution. Our analysis of three relatively isolated sources in the l=30{\\deg} and l=59{\\deg} Galactic fields show that the objects are partially resolved at 70$\\mu$m. The Herschel Hi-GAL survey data have a high scan velocity which makes unresolved and partially resolved sources appear elongated in the 70$\\mu$m images. We analysed the two scan directions separately and examine the intensity profile perpendicular to the scan direction. Spherically symmetric radiative transfer models with a power law density distribution were used to study the circumstellar matter distribution. Single dish sub-mm data were also included to study how different spatial information affects the fitted density distribution. The density distribution which best fits both the 70$\\mu$m intensity profile and SED has an average index of ~0.5. This index is shallower than expected an...

Olguin, F A; Wheelwright, H E; Clay, S J; de Wit, W -J; Rafiq, I; Pezzuto, S; Molinari, S

2015-01-01T23:59:59.000Z

442

Description of Stellar Acoustic Modes Using the Local Wave Concept  

E-Print Network [OSTI]

An understanding of stellar acoustic oscillations is attempted, using the local wave concept in semi-analytical calculations. The local homogeneity approximation allows to obtain simplified equations that can nevertheless describe the wave behavior down to the central region, as the gravitational potential perturbation is not neglected. Acoustic modes are calculated as classical standing waves in a cavity, by determining the cavity limits and the wave phases at these limits. The internal boundary condition is determined by a fitting with an Airy function. The external boundary condition is defined as the limit where the spatial variation of the background is important compared to the wavelength. This overall procedure is in accordance with the JWKB approximation. When comparing the results with numerical calculations, some drawbacks of the isothermal atmosphere approximation are revealed. When comparing with seismic observations of the Sun, possible improvements at the surface of solar models are suggested. The present semi-analytical method can potentially predict eigenfrequencies at the precision of +-3microHz in the range 800-5600 microHz, for the degrees l=0-10. A numerical calculation using the same type of external boundary conditions could reach a global agreement with observations better than 1 microHz. This approach could contribute to better determine the absolute values of eigenfrequencies for asteroseismology.

P. A. P. Nghiem

2006-06-26T23:59:59.000Z

443

THE RAVE CATALOG OF STELLAR ELEMENTAL ABUNDANCES: FIRST DATA RELEASE  

SciTech Connect (OSTI)

We present chemical elemental abundances for 36,561 stars observed by the RAdial Velocity Experiment (RAVE), an ambitious spectroscopic survey of our Galaxy at Galactic latitudes |b| > 25 Degree-Sign and with magnitudes in the range 9 stellar parameters, and it contains chemical abundances for the elements Mg, Al, Si, Ca, Ti, Fe, and Ni, with a mean error of {approx}0.2 dex, as judged from accuracy tests performed on synthetic and real spectra. Abundances are estimated through a dedicated processing pipeline in which the curve of growth of individual lines is obtained from a library of absorption line equivalent widths to construct a model spectrum that is then matched to the observed spectrum via a {chi}{sup 2} minimization technique. We plan to extend this pipeline to include estimates for other elements, such as oxygen and sulfur, in future data releases.

Boeche, C.; Williams, M.; De Jong, R. S.; Steinmetz, M. [Leibniz-Institut fuer Astrophysik Potsdam (AIP), D-14482 Potsdam (Germany); Siebert, A.; Bienayme, O. [Observatoire Astronomique de Strasbourg, Universite de Strasbourg, CNRS, UMR 7550, F-67000 Strasbourg (France); Fulbright, J. P.; Ruchti, G. R. [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Bland-Hawthorn, J. [Sydney Institute for Astronomy, School of Physics A28, University of Sydney, NSW 2006 (Australia); Campbell, R. [Department of Physics and Astronomy, Western Kentucky University, Bowling Green, KY (United States); Freeman, K. C. [Research School of Astronomy and Astrophysics, Australia National University, Weston Creek, Canberra ACT 2611 (Australia); Gibson, B. K. [Jeremiah Horrocks Institute, University of Central Lancashire, Preston PR1 2HE (United Kingdom); Gilmore, G. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Grebel, E. K. [Astronomisches Rechen-Institut, Zentrum fuer Astronomie der Universitaet Heidelberg, D-69120 Heidelberg (Germany); Helmi, A. [Kapteyn Astronomical Institute, University of Groningen, 9700 AV Groningen (Netherlands); Munari, U. [INAF Osservatorio Astronomico di Padova, Asiago I-36012 (Italy); Navarro, J. F. [Department of Physics and Astronomy, University of Victoria, Victoria BC V8W 3P6 (Canada); Parker, Q. A.; Reid, W. [Department of Physics and Astronomy, Faculty of Sciences, Macquarie University, Sydney, NSW 2109 (Australia); Seabroke, G. M. [Mullard Space Science Laboratory, University College London, Holmbury, St. Mary RH5 6NT (United Kingdom); and others

2011-12-15T23:59:59.000Z

444

12 Years of Stellar Activity Observations in Argentina  

E-Print Network [OSTI]

We present an observational program we started in 1999, to systematically obtain mid-resolution spectra of late-type stars, to study in particular chromospheric activity. In particular, we found cyclic activity in four dM stars, including Prox-Cen. We directly derived the conversion factor that translates the known S index to flux in the Ca II cores, and extend its calibration to a wider spectral range. We investigated the relation between the activity measurements in the calcium and hydrogen lines, and found that the usual correlation observed is the product of the dependence of each flux on stellar color, and it is not always preserved when simultaneous observations of a particular star are considered. We also used our observations to model the chromospheres of stars of different spectral types and activity levels, and found that the integrated chromospheric radiative losses, normalized to the surface luminosity, show a unique trend for G and K dwarfs when plotted against the S index.

Mauas, Pablo J D; Diaz, R; Vieytes, M; Petrucci, R; Jofre, E; Abrevaya, X; Luoni, M L; Valenzuela, P

2012-01-01T23:59:59.000Z

445

Asteroseismic determination of helium abundance in stellar envelopes  

E-Print Network [OSTI]

Intermediate degree modes of the solar oscillations have previously been used to determine the solar helium abundance to a high degree of precision. However, we cannot expect to observe such modes in other stars. In this work we investigate whether low degree modes that should be available from space-based asteroseismology missions can be used to determine the helium abundance, Y, in stellar envelopes with sufficient precision. We find that the oscillatory signal in the frequencies caused by the depression in \\Gamma_1 in the second helium ionisation zone can be used to determine the envelope helium abundance of low mass main sequence stars. For frequency errors of 1 part in 10^4, we expect errors \\sigma_Y in the estimated helium abundance to range from 0.03 for 0.8M_sun stars to 0.01 for 1.2M_sun stars. The task is more complicated in evolved stars, such as subgiants, but is still feasible if the relative errors in the frequencies are less than 10^{-4}.

Sarbani Basu; Anwesh Mazumdar; H. M Antia; Pierre Demarque

2004-02-15T23:59:59.000Z

446

Brown Dwarfs as Ejected Stellar Embryos: Observational Perspectives  

E-Print Network [OSTI]

We discuss a scenario in which brown dwarfs are formed like stars, except that their full collapse phases are interrupted through dynamical interactions in small multiple systems, leading to the ejection of the lightest member. This disintegration is a stochastic process, often resulting in the expulsion of newborn low mass stars, but when it occurs early enough the ejected stellar embryo will be a substellar object. This process may be so common at early ages that a large fraction of the ubiquitous brown dwarfs could have formed in this manner. Detailed gas dynamical simulations are required in order to better understand the details of the decay of small newborn multiple systems. We discuss the observational consequences of the ejection hypothesis, noting especially the importance of binaries with brown dwarf components as an observational test. Finally, we note that brown dwarfs that have recently been ejected may be so disturbed, by infall from the collapsing core and also by heavy accretion from perturbed circumstellar disks, that traditional spectral and luminosity criteria may fail to identify their substellar nature.

Bo Reipurth; Cathie Clarke

2002-08-31T23:59:59.000Z

447

The Evolved Red Stellar Content of M32  

E-Print Network [OSTI]

Near-infrared images obtained with the CFHT AOB are used to investigate the stellar content of the Local Group elliptical galaxy M32. Observations of a field 2.3 arcmin from the galaxy center reveal a large population of AGB stars, and comparisons with models indicate that these objects have an age log(t_Gyr) < 9.3. It is concluded that intermediate age stars account for roughly 25% of the total K light and 10% +/- 5% of the mass in this field. The K LF of bright sources between 20 and 30 arcsec from the nucleus is well matched by the LF of the outer regions of the galaxy after accounting for differences in surface brightness and correcting for crowding. It is concluded that the relative size of the intermediate age component with respect to other populations does not change with radius over most of the galaxy. However, the integrated J-K color and 2.3 micron CO index change with radius within a few tenths of an arcsec of the galaxy center indicating that, contrary to what might be inferred from observations at visible wavelengths, the integrated photometric properties of the central regions of M32 differ from those of the surrounding galaxy.

T. J. Davidge

2000-07-13T23:59:59.000Z

448

Lithium in Blanco1: Implications for Stellar Mixing  

E-Print Network [OSTI]

We obtain lithium abundances for G and K stars in Blanco 1, an open cluster with an age similar to, or slightly younger than, the Pleiades. We critically examine previous spectroscopic abundance analyses of Blanco 1 and conclude that while there were flaws in earlier work, it is likely that Blanco 1 is close in overall metallicity to the older Hyades cluster and more metal-rich than the Pleiades. However, we find Blanco 1 has Li abundances and rotation rates similar to the Pleiades, contradicting predictions from standard stellar evolution models, in which convective pre-main sequence (PMS) Li depletion should increase rapidly with metallicity. If the high metallicity of Blanco 1 is subsequently confirmed, our observations imply (1) that a currently unknown mechanism severely inhibits PMS Li depletion, (2) that additional non-standard mixing modes, such as those driven by rotation and angular momentum loss, are then responsible for main sequence Li depletion between the ages of Blanco 1 and the Hyades, and (3) that in clusters younger than the Hyades, metallicity plays only a minor role in determining the amount of Li depletion among G and K stars. These conclusions suggest that Li abundance remains a useful age indicator among young (less than 700 Myr) stars even when metallicities are unknown. If non-standard mixing is effective in Population I stars, the primordial Li abundance could be significantly larger than present day Population II Li abundances, due to prior Li depletion.

R. D. Jeffries; D. J. James

1998-09-11T23:59:59.000Z

449

Improved Moving Puncture Gauge Conditions for Compact Binary Evolutions  

E-Print Network [OSTI]

Robust gauge conditions are critically important to the stability and accuracy of numerical relativity (NR) simulations involving compact objects. Most of the NR community use the highly robust---though decade-old---moving-puncture (MP) gauge conditions for such simulations. It has been argued that in binary black hole (BBH) evolutions adopting this gauge, noise generated near adaptive-mesh-refinement (AMR) boundaries does not converge away cleanly with increasing resolution, severely limiting gravitational waveform accuracy at computationally feasible resolutions. We link this noise to a sharp (short-wavelength), initial outgoing gauge wave crossing into progressively lower resolution AMR grids, and present improvements to the standard MP gauge conditions that focus on stretching, smoothing, and more rapidly settling this outgoing wave. Our best gauge choice greatly reduces gravitational waveform noise during inspiral, yielding less fluctuation in convergence order and $\\sim 40%$ lower waveform phase and amplitude errors at typical resolutions. Noise in other physical quantities of interest is also reduced, and constraint violations drop by more than an order of magnitude. We expect these improvements will carry over to simulations of all types of compact binary systems, as well as other $N$+1 formulations of gravity for which MP-like gauge conditions can be chosen.

Zachariah B. Etienne; John G. Baker; Vasileios Paschalidis; Bernard J. Kelly; Stuart L. Shapiro

2014-10-06T23:59:59.000Z

450

Microwave sintering of pure and doped nanocrystalline alumina compacts  

SciTech Connect (OSTI)

A single-mode cavity microwave furnace, operating in the TE{sub 103} mode at 2.45 GHz is being used to investigate sintering of pure and doped nanocrystalline alumina. The purpose of these experiments is to determine the effect of additives on the sintering process in the nanocrystalline regime. Using the sol-gel method, high purity Al{sub 2}O{sub 3} nanocrystalline powders were synthesized. These powders were calcined at 700 C and then CIP`ed to 414 MPa, producing 0.4 in. diameter, 0.25 in. high cylindrical compacts. The compacts were heated in the microwave furnace to temperatures between 1,100 C to approximately 1,800 C and were then brought back to room temperature using a triangular heating profile of about 30 minutes duration. A two-color IR pyrometer was used to monitor the surface temperature of the workpiece. The additives tested in this work lowered the temperature needed for densification but this effect was offset by increased grain growth. Initial grain growth from <5 nm to {approximately}50 nm was closely correlated with the {gamma} to {alpha}-alumina phase transition.

Bruce, R.W. [SFA, Inc., Largo, MD (United States); Fliflet, A.W.; Lewis, D. III; Rayne, R.J.; Bender, B.A.; Chow, G.M.; Schoen, P.E. [Naval Research Lab., Washington, DC (United States); Kurihara, L.K. [Georgetown Univ., Washington, DC (United States). Dept. of Biochemistry

1996-12-31T23:59:59.000Z

451

On the properties of massive Population III stars and metal-free stellar populations  

E-Print Network [OSTI]

We present realistic models for massive Population III stars and stellar populations based on non-LTE model atmospheres, recent stellar evolution tracks and up-to-date evolutionary synthesis models, to study their spectral properties, including their dependence on age, star formation history, and IMF. (..) The main results regarding integrated stellar populations are: * For young bursts and the case of a constant SFR, nebular continuous emission - neglected in previous studies - dominates the spectrum redward of Lyman-alpha (...). Therefore predicted emission line equivalent widths are considerably smaller than found in earlier studies, whereas the detection of the continuum is eased. Nebular line and continuous emission strongly affect the broad band photometric properties of Pop III objects. * Due to stellar evolution, the hardness of the ionising spectrum decreases rapidly, leading to the disappearance of the characteristic HeII 1640 recombination lines after ~ 3 Myr in instantaneous bursts. * The relative...

Schärer, D

2001-01-01T23:59:59.000Z

452

Catching the fish - Constraining stellar parameters for TX Psc using spectro-interferometric observations  

E-Print Network [OSTI]

Stellar parameter determination is a challenging task when dealing with galactic giant stars. The combination of different investigation techniques has proven to be a promising approach. We analyse archive spectra obtained with the Short-Wavelength-Spectrometer (SWS) onboard of ISO, and new interferometric observations from the Very Large Telescope MID-infrared Interferometric instrument (VLTI/MIDI) of a very well studied carbon-rich giant: TX Psc. The aim of this work is to determine stellar parameters using spectroscopy and interferometry. The observations are used to constrain the model atmosphere, and eventually the stellar evolutionary model in the region where the tracks map the beginning of the carbon star sequence. Two different approaches are used to determine stellar parameters: (i) the 'classic' interferometric approach where the effective temperature is fixed by using the angular diameter in the N-band (from interferometry) and the apparent bolometric magnitude; (ii) parameters are obtained by fit...

Klotz, D; Hron, J; Aringer, B; Sacuto, S; Marigo, P; Verhoelst, T

2013-01-01T23:59:59.000Z

453

The effects of compaction of different golf green soil mixtures on plant growth  

E-Print Network [OSTI]

growth, removed prior Co compaction treatments, from mixtures of different sand- clay soll-peat rstlosoeoooeoo ~ ~ aeoaoae ~ o oo ~ o ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 7e An average of 2 clipping yields of top growth, removed after Che compaction and during...-clay soil-peat rs'tlos ~ a ~ eaoaoaeooaeeaa ~ o ~ aeea e ~ o ~ eaeoao ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ a ~ aooo 28 9e Differential effects of the different sand-clay soll-peat ratios of 5 particle size mixtures on yields of 2 clip plugs following Che compaction...

Kunze, Raymond John

1956-01-01T23:59:59.000Z

454

DAVID BEN-ZVI Once we know that QC is compactly generated, it becomes easy to  

E-Print Network [OSTI]

step up, for gerbes need to go to steps up. Consider a map X Y . Then we have a Cech simplicial objectTRIAGE DAVID BEN-ZVI Once we know that QC is compactly generated, it becomes easy to prove that QC-compact separated schemes QC(X) is compactly generated by perfect objects. Let U = Ui Z an open cover. A functor

Proudfoot, Nicholas

455

Effect of surface compaction on the moisture content of piled green hardwood chips  

SciTech Connect (OSTI)

Simulators of chip piles were used to evaluate the effect of surface compaction on the amount of water retained by green hardwood whole stem chips exposed to incident rainfall. Pile surfaces compacted with heavy chip handling equipment will absorb water at an approximate 18% slower rate than those without surface compaction providing there is sufficient slope in the pile surfaces to facilitate rain water runoff.

White, M.S.; Vodak, M.C.; Cupp, D.C.

1984-05-01T23:59:59.000Z

456

Non-axisymmetric equilibrium reconstruction for stellarators, reversed field pinches and tokamaks  

SciTech Connect (OSTI)

Axisymmetric equilibrium reconstruction using magnetohydrodynamic equilibrium solutions to the Grad Shafranov equation has long been an important tool for interpreting tokamak experiments. This paper describes recent results in non-axisymmetric (three-dimensional) equilibrium reconstruction of nominally axisymmetric plasmas (tokamaks and reversed field pinches (RFPs)), and fully non-axisymmetric plasmas (stellarators). Results from applying the V3FIT code to CTH and HSX stellarator plasmas, RFX-mod RFP plasmas and the DIII-D tokamak are presented.

Hanson, James D. [Auburn University, Auburn, Alabama; Anderson, D.T. [University of Wisconsin, Madison; Cianciosa, M. [Auburn University, Auburn, Alabama; Franz, P. [EURATOM / ENEA, Italy; Harris, J. H. [Oak Ridge National Laboratory (ORNL); Hartwell, G. H. [Auburn University, Auburn, Alabama; Hirshman, Steven Paul [ORNL; Knowlton, Stephen F. [Auburn University, Auburn, Alabama; Lao, Lang L. [General Atomics, San Diego; Lazarus, Edward Alan [ORNL; Marrelli, L. [Association EURATOM ENEA Fusion, Consorzio RFX, Padua, Italy; Maurer, D. A. [Auburn University, Auburn, Alabama; Schmitt, J. C. [Princeton Plasma Physics Laboratory (PPPL); Sontag, A. C. [Oak Ridge National Laboratory (ORNL); Stevenson, B. A. [Auburn University, Auburn, Alabama; Terranova, D. [Association EURATOM ENEA Fusion, Consorzio RFX, Padua, Italy

2013-01-01T23:59:59.000Z

457

Diffusion and Swelling Measurements in Pharmaceutical Powder Compacts Using Terahertz Pulsed Imaging  

E-Print Network [OSTI]

the Morphologi v8.11 software (Malvern In- struments). The mean particle size, D50, of HPMC, Eudragit RSPO, and Lactose were 16.9, 8.6, and 22.1 :m, respectively. Compaction Tablets were compressed to 1.5 mm thickness, either by using a manual hydraulic press... - prisingly, the tablets produced using the compaction simulator exhibited a more consistent pore distribution compared with the ones produced using the hydraulic press that reflects the more controlled method of compaction in the compaction simu- lator...

Yassin, Samy; Su, Ke; Lin, Hungyen; Gladden, Lynn F.; Zeitler, J. Axel

2015-02-02T23:59:59.000Z

458

Cape Light Compact- Commercial, Industrial and Municipal Buildings Energy Efficiency Rebate Program  

Broader source: Energy.gov [DOE]

Through a multi-member partnership, Cape Light Compact (CLC) and Masssave offer a variety of financial incentives for commercial, industrial, and municipal facilities. Custom rebate options are...

459

A Superconducting Bending Magnet System for a Compact Synchrotron Light Source  

E-Print Network [OSTI]

Garren, "Optimization of Superconducting Bending Magnets foral, "Development of a Superconducting Compact Storage Ringsdesigns M. A Green, "Superconducting Dipole Magnets for

Green, M.A.

2011-01-01T23:59:59.000Z

460

E-Print Network 3.0 - agglomerates iii compaction Sample Search...  

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

phase Summary: agglomerated a powder is, the lower the green density will be upon compacting this powder and the larger... of all preparation routes was the synthesis of...

Note: This page contains sample records for the topic "national compact stellarator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Los Alamos National Laboratory  

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

23, 2013-Nearly 400 Los Alamos National Laboratory employees on 47 teams received Pollution Prevention awards for protecting the environment and saving taxpayers more than 8...

462

National Day of Remembrance  

SciTech Connect (OSTI)

Ames Laboratory observed the National Day of Remembrance for weapons workers from the Cold War era with a ceremony held Oct. 27, 2009 at the Ames Public Library.

None

2010-01-01T23:59:59.000Z

463

National Energy Awareness Month  

Broader source: Energy.gov [DOE]

October is National Energy Awareness Month. It's also a chance to talk about our country’s energy security and its clean energy future.

464

Idaho National Laboratory Facilities  

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

National Scientific User Facility Center for Advanced Energy Studies Light Water Reactor Sustainability Idaho Regional Optical Network LDRD Next Generation Nuclear Plant Docs...

465

Idaho National Laboratory Newsroom  

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

list of common INL acronyms and abbreviations. Page Contact Information: Nicole Stricker (208) 526-5955 Email Contact Feature Story Counting the ways Idaho National...

466

2012 National Electricity Forum  

Broader source: Energy.gov (indexed) [DOE]

or direct us to appropriate source materials.) To the extent that you believe your region has conditional congestion of national significance, what are the factors or...

467

National Nuclear Security Administration  

National Nuclear Security Administration (NNSA)

the Earth's Surface. The second virtual classroom to the student was presented by Tommy Smith from Lawrence Livermore National Laboratory on various sources of energy, its use and...

468

National Nuclear Security Administration  

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

Project Reviews, etc., except those specifically reserved for the Administrator for the National Nuclear Security Administration and the Deputy Secretary. cc: Mike Hickman. NA-Stl...

469

National Cybersecurity Awareness Month  

Broader source: Energy.gov (indexed) [DOE]

National Cybersecurity Awareness Month (NCSAM) October 2013 Every October, the Department of Energy joins the Department of Homeland Security (DHS) and others across the country...

470

National Laboratory Photovoltaics Research  

Broader source: Energy.gov [DOE]

DOE supports photovoltaic (PV) research and development and facilities at its national laboratories to accelerate progress toward achieving the SunShot Initiative's technological and economic...

471

Los Alamos National Laboratory  

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

this tenth member of our National Centers for Systems Biology program," said James Anderson, who oversees systems biology awards at NIGMS. "The new center will apply...

472

national security campus | National Nuclear Security Administration  

National Nuclear Security Administration (NNSA)

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473

National Postdoctoral Association | Argonne National Laboratory  

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

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474

National Security Science | Los National Alamos Laboratory  

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

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475

National Security Science | Los National Alamos Laboratory  

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

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476

National Security Science | Los National Alamos Laboratory  

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

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477

National Security Science | Los National Alamos Laboratory  

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

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478

National Security Science | Los National Alamos Laboratory  

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

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479

National Security Science | Los National Alamos Laboratory  

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

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480

STELLAR COLLISIONS AND BLUE STRAGGLER STARS IN DENSE GLOBULAR CLUSTERS  

SciTech Connect (OSTI)

Blue straggler stars (BSSs) are abundantly observed in all Galactic globular clusters (GGCs) where data exist. However, observations alone cannot reveal the relative importance of various formation channels or the typical formation times for this well-studied population of anomalous stars. Using a state-of-the-art Hénon-type Monte Carlo code that includes all relevant physical processes, we create 128 models with properties typical of the observed GGCs. These models include realistic numbers of single and binary stars, use observationally motivated initial conditions, and span large ranges in central density, concentration, binary fraction, and mass. Their properties can be directly compared with those of observed GGCs. We can easily identify the BSSs in our models and determine their formation channels and birth times. We find that for central densities above ?10{sup 3} M{sub ?} pc{sup –3}, the dominant formation channel is stellar collisions, while for lower density clusters, mass transfer in binaries provides a significant contribution (up to 60% in our models). The majority of these collisions are binary-mediated, occurring during three-body and four-body interactions. As a result, a strong correlation between the specific frequency of BSSs and the binary fraction in a cluster can be seen in our models. We find that the number of BSSs in the core shows only a weak correlation with the collision rate estimator ? traditionally used by observers, in agreement with the latest Hubble Space Telescope Advanced Camera for Surveys data. Using an idealized 'full mixing' prescription for collision products, our models indicate that the BSSs observed today may have formed several Gyr ago. However, denser clusters tend to have younger (?1 Gyr) BSSs.

Chatterjee, Sourav [Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States); Rasio, Frederic A. [Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 (United States); Sills, Alison [Department of Physics and Astronomy, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4M1 (Canada); Glebbeek, Evert, E-mail: s.chatterjee@astro.ufl.edu [Department of Astrophysics/IMAPP, Radboud University Nijmegen, P.O. Box 9010, 6500 GL Nijmegen (Netherlands)

2013-11-10T23:59:59.000Z

Note: This page contains sample records for the topic "national compact stellarator" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


481

The Solar Heavy Element Abundances: I. Constraints from Stellar Interiors  

E-Print Network [OSTI]

The latest solar atmosphere models include non-LTE corrections and 3D hydrodynamic convection simulations. These models predict a significant reduction in the solar metal abundance, which leads to a serious conflict between helioseismic data and the predictions of solar interiors models. We demonstrate that the helioseismic constraints on the surface convection zone depth and helium abundance combined with stellar interiors models can be used to define the goodness of fit for a given chemical composition. After a detailed examination of the errors in the theoretical models we conclude that models constructed with the older solar abundances are consistent (seismic data. Models constructed with the proposed new low abundance scale are strongly disfavored, disagreeing at the 15 \\sigma level. We then use the sensitivity of the seismic properties to abundance changes to invert the problem and infer a seismic solar heavy element abundance mix with two components: meteoritic abundances, and the light metals CNONe. Seismic degeneracies between the best solutions for the elements arise for changes in the relative CNONe abundances and their effects are quantified. We obtain Fe/H=7.50+/-0.045+/-0.003(CNNe) and O/H=8.86+/-0.041+/-0.025(CNNe) for the relative CNNe in the GS98 mixture. The inferred solar oxygen abundance disagree with the abundance inferred from the 3D hydro models. Changes in the Ne abundance can mimic changes in O for the purposes of scalar constraints.Models constructed with low oxygen and high neon are inconsistent with the solar sound speed profile. The implications for the solar abundance scale are discussed.

Franck Delahaye; Marc Pinsonneault

2005-11-29T23:59:59.000Z

482

Water destruction by X-rays in young stellar objects  

E-Print Network [OSTI]

We study the H2O chemistry in star-forming environments under the influence of a central X-ray source and a central far ultraviolet (FUV) radiation field. The gas-phase water chemistry is modeled as a function of time, hydrogen density and X-ray flux. To cover a wide range of physical environments, densities between n_H = 10^4-10^9 cm^-3 and temperatures between T = 10-1000 K are studied. Three different regimes are found: For T water abundance is of order 10^-7-10^-6 and can be somewhat enhanced or reduced due to X-rays, depending on time and density. For 100 K 10^-3 ergs s-1 cm^-2 (t = 10^4 yrs) and for F_X > 10^-4 ergs s^-1 cm^-2 (t = 10^5 yrs). At higher temperatures (T > 250 K) and hydrogen densities, water can persist with x(H2O) ~ 10^-4 even for high X-ray fluxes. The X-ray and FUV models are applied to envelopes around low-mass Class 0 and I young stellar objects (YSOs). Water is destroyed in both Class 0 and I envelopes on relatively short timescales (t ~ 5000 yrs) for realistic X-ray fluxes, although the effect is less prominent in Class 0 envelopes due to the higher X-ray absorbing densities there. FUV photons from the central source are not effective in destroying water. The average water abundance in Class I sources for L_X > 10^27 ergs s^-1 is predicted to be x(H2O) < 10^-6.

P. Stauber; J. K. Jorgensen; E. F. van Dishoeck; S. D. Doty; A. O. Benz

2006-02-06T23:59:59.000Z

483

Test Area for Remedial Actions (TARA) site characterization and dynamic compaction of low-level radioactive waste trenches. FY 1988 progress report  

SciTech Connect (OSTI)

As part of a low-level radioactive waste burial ground stabilization and closure technology demonstration project, a group of five burial trenches in Oak Ridge National Laboratory (ORNL) Solid Waste Storage Area (SWSA) 6 was selected as a demonstration site for testing trench compaction, trench grouting, and trench cap installation and performance. This report focuses on site characterization, trench compaction, and grout-trench leachate compatibility. Trench grouting and cap design and construction will be the subject of future reports. The five trenches, known as the Test Area for Remedial Actions (TARA) site, are contained within a hydrologically isolated area of SWSA 6; for that reason, any effects of stabilization activities on site performance and groundwater quality will be separable from the influence of other waste disposal units in SWSA 6. To obviate the chronic problem of burial trench subsidence and to provide support for an infiltration barrier cap, these five trenches were dynamically compacted by repeated dropping of a 4-ton weight onto each trench from heights of approximately 7 m.

Davis, E.C.; Spalding, B.P.; Lee, S.Y.; Hyder, L.K.

1989-01-01T23:59:59.000Z

484

National Park Service- Yellowstone National Park, Wyoming  

Broader source: Energy.gov [DOE]

Yellowstone National Park, Wyoming, has many historical sites within its boundaries. One of these is the Lamar Buffalo Ranch, a ranch that was set up in the early 1900s to breed buffalo for replacement stock within the park during a time when their numbers were very low. The ranch buildings are currently being used by the Yellowstone Association Institute for ecology classes.

485

National Research Council Canada  

E-Print Network [OSTI]

National Research Council Canada Institute for Information Technology Conseil national de recherches Canada Institut de technologie de l'information Determining Internet Users' Values for Private in The Second Annual Conference on Privacy, Security and Trust (PST'04). Fredericton, New Brunswick, Canada

Fleming, Michael W.

486

INDIAN NATIONAL SCIENCE ACADEMY  

E-Print Network [OSTI]

INDIAN NATIONAL SCIENCE ACADEMY Science academies play a crucial role in promoting, recognizing and bring out proceedings and monographs. The academies promote public awareness and understanding the country. In this section the growth of the Indian National Science Academy and its functions

Srinivasan, N.

487

National Energy Software Center  

SciTech Connect (OSTI)

A short introduction is given to the services of the National Energy Software Library at the Argonne National Laboratory. The objectives, history, and software collection of the center are presented. Information on ordering from the software collection of the library is also included. 4 refs., 3 tabs. (DWL)

Eyberger, L.R.

1986-01-01T23:59:59.000Z

488

National Osteoporosis Prevention Month  

E-Print Network [OSTI]

MAY National Osteoporosis Prevention Month JUNE National Dairy Month Texas AgriLife Extension - Bone Health Power Point # P4-1 Eat Smart for Bone Health # P4-2 Osteoporosis Disease Statistics # P4-3 Osteoporosis = Porous Bones # P4-4 Risk Factors # P4-5 Risk Factors (continued) # P4-6 Steps to Prevention # P4

489

The National Cancer Institute,  

E-Print Network [OSTI]

The National Cancer Institute, International Cancer Information Center Bldg. 82, Rm 123 Bethesda, MD 20892 The National Cancer Institute (NCI) is part of the Federal Government. NCI coordinates the government's cancer research program. It is the largest of the 17 biomedical research institutes and centers

490

B physics expected performances with the Compact Muon Solenoid detector  

SciTech Connect (OSTI)

We present here the future performances of the Compact Muon Solenoid detector for B physics. We show that CMS will contribute significantly to the CP violation parameter sin 2{beta} measurement with a precision of {delta} sin 2{beta}{approx_equal}0.02 (1 year of integrated luminosity). The asymetry in the channel B{sub s}{sup 0}{yields}J/{psi}{phi} will be tested to the 2-5% level. The mixing parameter x{sub s} of B{sub s}{sup 0} oscillations will be measured up to 40. Finaly the rare B decay should be searched down to the SM expectation and in the case of the semileptonic rare decays will provide enough statistics to performed detailed studies.

Charles, Francois [Groupe de Recherche en Physique des Hautes Energies, Universite de Haute Alsace, 61 rue A. Camus, 68093 Mulhouse (France)

1998-10-19T23:59:59.000Z

491

Collisional Hardening of Compact Binaries in Globular Clusters  

E-Print Network [OSTI]

We consider essential mechanisms for orbit-shrinkage or "hardening" of compact binaries in globular clusters to the point of Roche-lobe contact and X-ray emission phase, focussing on the process of collisional hardening due to encounters between binaries and single stars in the cluster core. The interplay between this kind of hardening and that due to emission of gravitational radiation produces a characteristic scaling of the orbit-shrinkage time with the single-star binary encounter rate $\\gamma$ in the cluster which we introduce, clarify, and explore. We investigate possible effects of this scaling on populations of X-ray binaries in globular clusters within the framework of a simple "toy" scheme for describing the evolution of pre-X-ray binaries in globular clusters. We find the expected qualitative trends sufficiently supported by data on X-ray binaries in galactic globular clusters to encourage us toward a more quantitative study.

S. Banerjee; P. Ghosh

2006-09-29T23:59:59.000Z

492

Phase conversion dissipation in multi-component compact stars  

E-Print Network [OSTI]

We propose a mechanism for the damping of density oscillations in multi-component compact stars. The mechanism is the periodic conversion between different phases, i.e. the movement of the interface between them, induced by pressure oscillations in the star. The damping grows nonlinearly with the amplitude of the oscillation. We study in detail the case of r-modes in a hybrid star with a sharp interface, and we find that this mechanism is powerful enough to saturate the r-mode at very low saturation amplitude, of order $10^{-10}$, and is therefore likely to be the dominant r-mode saturation mechanism in hybrid stars with a sharp interface.

Mark G. Alford; Sophia Han; Kai Schwenzer

2015-01-15T23:59:59.000Z

493

Compact mass spectrometer for plasma discharge ion analysis  

DOE Patents [OSTI]

A mass spectrometer and methods are disclosed for mass spectrometry which are useful in characterizing a plasma. This mass spectrometer for determining type and quantity of ions present in a plasma is simple, compact, and inexpensive. It accomplishes mass analysis in a single step, rather than the usual two-step process comprised of ion extraction followed by mass filtering. Ions are captured by a measuring element placed in a plasma and accelerated by a known applied voltage. Captured ions are bent into near-circular orbits by a magnetic field such that they strike a collector, producing an electric current. Ion orbits vary with applied voltage and proton mass ratio of the ions, so that ion species may be identified. Current flow provides an indication of quantity of ions striking the collector. 7 figs.

Tuszewski, M.G.

1997-07-22T23:59:59.000Z

494

Evidence for compact structuring in the corona of active stars  

E-Print Network [OSTI]

The ``current wisdom'' regarding the structuring of the X-ray emitting corona in active stars (i.e. a corona dominated by extended coronal structures) is briefly reviewed, followed by a review of a new approach to flare analysis and the analysis of a significant number of newly observed and previously published large flares, all leading to a much more compactly structured corona. Recent observations showing the polar location of the flaring plasma are then discussed, showing how the current evidence points toward a (flaring) corona composed of rather low-lying polar structures, also in agreement with some recent radio VLBI observational results and with starspot Doppler images. The resulting picture is significantly different from the solar case.

F. Favata

2000-11-27T23:59:59.000Z

495

Compact light source performance in recessed type luminaires  

SciTech Connect (OSTI)

Photometric comparisons were made with an indoor, recessed, type luminaire using incandescent, high intensity discharge and compact fluorescent lamps. The test results show substantial performance advantages, as expected, for the discharge light sources where the efficacy gains can be in the order for 400% even when including the ballast losses associated with the discharge lamps. The candlepower distribution patterns emerging from these luminaries are also different from those associated with the baseline incandescent lamps, and which are in some ways, even more desirable from a uniformity of illuminance perspective. A section on fluorescent lamp starting is also included which describes a system having excellent starting characteristics in terms of electrode starting temperature (RH/RC technique), proper operating frequency to minimize unwanted IR interactions, and satisfactory current crest factor values to help insure life performance.

Hammer, E.E.

1998-11-01T23:59:59.000Z

496

Compact cladding-pumped planar waveguide amplifier and fabrication method  

DOE Patents [OSTI]

A low-cost, high performance cladding-pumped planar waveguide amplifier and fabrication method, for deployment in metro and access networks. The waveguide amplifier has a compact monolithic slab architecture preferably formed by first sandwich bonding an erbium-doped core glass slab between two cladding glass slabs to form a multi-layer planar construction, and then slicing the construction into multiple unit constructions. Using lithographic techniques, a silver stripe is deposited and formed at a top or bottom surface of each unit construction and over a cross section of the bonds. By heating the unit construction in an oven and applying an electric field, the silver stripe is then ion diffused to increase the refractive indices of the core and cladding regions, with the diffusion region of the core forming a single mode waveguide, and the silver diffusion cladding region forming a second larger waveguide amenable to cladding pumping with broad area diodes.

Bayramian, Andy J.; Beach, Raymond J.; Honea, Eric; Murray, James E.; Payne, Stephen A.

2003-10-28T23:59:59.000Z

497

Compact mass spectrometer for plasma discharge ion analysis  

DOE Patents [OSTI]

A mass spectrometer and methods for mass spectrometry which are useful in characterizing a plasma. This mass spectrometer for determining type and quantity of ions present in a plasma is simple, compact, and inexpensive. It accomplishes mass analysis in a single step, rather than the usual two-step process comprised of ion extraction followed by mass filtering. Ions are captured by a measuring element placed in a plasma and accelerated by a known applied voltage. Captured ions are bent into near-circular orbits by a magnetic field such that they strike a collector, producing an electric current. Ion orbits vary with applied voltage and proton mass ratio of the ions, so that ion species may be identified. Current flow provides an indication of quantity of ions striking the collector.

Tuszewski, Michel G. (Los Alamos, NM)

1997-01-01T23:59:59.000Z

498

Compact Gamma-ray Source Technology Development Study  

SciTech Connect (OSTI)

This study focuses on the applicability of current accelerator and laser technologies to the construction of compact, narrow bandwidth, gamma-ray sources for DHS missions in illicit materials detection. It also identifies research and development areas in which advancement will directly benefit these light sources. In particular, we review the physics of Compton scattering based light sources and emphasize the source properties most important to Nuclear Resonance Fluorescence (NRF) applications of interest. The influences of laser and electron beam properties on the light source are examined in order to evaluate the utility of different technologies for this application. Applicable bulk and fiber-based laser systems and laser recirculation technologies are discussed and Radio Frequency (RF) Linear Accelerator (linac) technologies are examined to determine the optimal frequency and pulse formats achievable.

Anderson, S G; Gibson, D J; Rusnak, B

2009-09-25T23:59:59.000Z

499

COMPACT, TUNABLE COMPTON SCATTERING GAMMA-RAY SOURCES  

SciTech Connect (OSTI)

Recent progress in accelerator physics and laser