National Library of Energy BETA

Sample records for larger core models

  1. The core legion object model

    SciTech Connect (OSTI)

    Lewis, M.; Grimshaw, A.

    1996-12-31

    The Legion project at the University of Virginia is an architecture for designing and building system services that provide the illusion of a single virtual machine to users, a virtual machine that provides secure shared object and shared name spaces, application adjustable fault-tolerance, improved response time, and greater throughput. Legion targets wide area assemblies of workstations, supercomputers, and parallel supercomputers, Legion tackles problems not solved by existing workstation based parallel processing tools; the system will enable fault-tolerance, wide area parallel processing, inter-operability, heterogeneity, a single global name space, protection, security, efficient scheduling, and comprehensive resource management. This paper describes the core Legion object model, which specifies the composition and functionality of Legion`s core objects-those objects that cooperate to create, locate, manage, and remove objects in the Legion system. The object model facilitates a flexible extensible implementation, provides a single global name space, grants site autonomy to participating organizations, and scales to millions of sites and trillions of objects.

  2. The role of subsurface flows in solar surface convection: modeling the spectrum of supergranular and larger scale flows

    SciTech Connect (OSTI)

    Lord, J. W.; Rast, M. P.; Cameron, R. H.; Rempel, M.; Roudier, T.

    2014-09-20

    We model the solar horizontal velocity power spectrum at scales larger than granulation using a two-component approximation to the mass continuity equation. The model takes four times the density scale height as the integral (driving) scale of the vertical motions at each depth. Scales larger than this decay with height from the deeper layers. Those smaller are assumed to follow a Kolmogorov turbulent cascade, with the total power in the vertical convective motions matching that required to transport the solar luminosity in a mixing length formulation. These model components are validated using large-scale radiative hydrodynamic simulations. We reach two primary conclusions. (1) The model predicts significantly more power at low wavenumbers than is observed in the solar photospheric horizontal velocity spectrum. (2) Ionization plays a minor role in shaping the observed solar velocity spectrum by reducing convective amplitudes in the regions of partial helium ionization. The excess low wavenumber power is also seen in the fully nonlinear three-dimensional radiative hydrodynamic simulations employing a realistic equation of state. This adds to other recent evidence suggesting that the amplitudes of large-scale convective motions in the Sun are significantly lower than expected. Employing the same feature tracking algorithm used with observational data on the simulation output, we show that the observed low wavenumber power can be reproduced in hydrodynamic models if the amplitudes of large-scale modes in the deep layers are artificially reduced. Since the large-scale modes have reduced amplitudes, modes on the scale of supergranulation and smaller remain important to convective heat flux even in the deep layers, suggesting that small-scale convective correlations are maintained through the bulk of the solar convection zone.

  3. Mechanisms and Geochemical Models of Core Formation

    E-Print Network [OSTI]

    Rubie, David C

    2015-01-01

    The formation of the Earth's core is a consequence of planetary accretion and processes in the Earth's interior. The mechanical process of planetary differentiation is likely to occur in large, if not global, magma oceans created by the collisions of planetary embryos. Metal-silicate segregation in magma oceans occurs rapidly and efficiently unlike grain scale percolation according to laboratory experiments and calculations. Geochemical models of the core formation process as planetary accretion proceeds are becoming increasingly realistic. Single stage and continuous core formation models have evolved into multi-stage models that are couple to the output of dynamical models of the giant impact phase of planet formation. The models that are most successful in matching the chemical composition of the Earth's mantle, based on experimentally-derived element partition coefficients, show that the temperature and pressure of metal-silicate equilibration must increase as a function of time and mass accreted and so m...

  4. Multi-core Technologies Model Design and System Architecture

    E-Print Network [OSTI]

    Albanese, Claudio

    Multi-core Technologies Model Design and System Architecture Conclusions High Performance Pricing-core Technologies Model Design and System Architecture Conclusions Summary Multi-core Technologies Model Design Model Design and System Architecture Conclusions Banking, Mathematics and Technology Modern banking

  5. Comprehensive chemical kinetic modeling of the oxidation of C8 and larger n-alkanes and 2-methylalkanes

    SciTech Connect (OSTI)

    Sarathy, S M; Westbrook, C K; Pitz, W J; Mehl, M; Togbe, C; Dagaut, P; Wang, H; Oehlschlaeger, M; NIemann, U; Seshadri, K; Veloo, P S; Ji, C; Egolfopoulos, F; Lu, T

    2011-03-16

    Conventional petroleum jet and diesel fuels, as well as alternative Fischer-Tropsch (FT) fuels and hydrotreated renewable jet (HRJ) fuels, contain high molecular weight lightly branched alkanes (i.e., methylalkanes) and straight chain alkanes (n-alkanes). Improving the combustion of these fuels in practical applications requires a fundamental understanding of large hydrocarbon combustion chemistry. This research project presents a detailed and reduced chemical kinetic mechanism for singly methylated iso-alkanes (i.e., 2-methylalkanes) ranging from C{sub 8} to C{sub 20}. The mechanism also includes an updated version of our previously published C{sub 8} to C{sub 16} n-alkanes model. The complete detailed mechanism contains approximately 7,200 species 31,400 reactions. The proposed model is validated against new experimental data from a variety of fundamental combustion devices including premixed and nonpremixed flames, perfectly stirred reactors and shock tubes. This new model is used to show how the presence of a methyl branch affects important combustion properties such as laminar flame propagation, ignition, and species formation.

  6. Recent developments in no-core shell-model calculations

    E-Print Network [OSTI]

    Petr Navratil; Sofia Quaglioni; Ionel Stetcu; Bruce R. Barrett

    2009-04-02

    We present an overview of recent results and developments of the no-core shell model (NCSM), an ab initio approach to the nuclear many-body problem for light nuclei. In this approach, we start from realistic two-nucleon or two- plus three-nucleon interactions. Many-body calculations are performed using a finite harmonic-oscillator (HO) basis. To facilitate convergence for realistic inter-nucleon interactions that generate strong short-range correlations, we derive effective interactions by unitary transformations that are tailored to the HO basis truncation. For soft realistic interactions this might not be necessary. If that is the case, the NCSM calculations are variational. In either case, the ab initio NCSM preserves translational invariance of the nuclear many-body problem. In this review, we, in particular, highlight results obtained with the chiral two- plus three-nucleon interactions. We discuss efforts to extend the applicability of the NCSM to heavier nuclei and larger model spaces using importance-truncation schemes and/or use of effective interactions with a core. We outline an extension of the ab initio NCSM to the description of nuclear reactions by the resonating group method technique. A future direction of the approach, the ab initio NCSM with continuum, which will provide a complete description of nuclei as open systems with coupling of bound and continuum states, is given in the concluding part of the review.

  7. Recent Developments in No-Core Shell-Model Calculations

    SciTech Connect (OSTI)

    Navratil, P; Quaglioni, S; Stetcu, I; Barrett, B R

    2009-03-20

    We present an overview of recent results and developments of the no-core shell model (NCSM), an ab initio approach to the nuclear many-body problem for light nuclei. In this aproach, we start from realistic two-nucleon or two- plus three-nucleon interactions. Many-body calculations are performed using a finite harmonic-oscillator (HO) basis. To facilitate convergence for realistic inter-nucleon interactions that generate strong short-range correlations, we derive effective interactions by unitary transformations that are tailored to the HO basis truncation. For soft realistic interactions this might not be necessary. If that is the case, the NCSM calculations are variational. In either case, the ab initio NCSM preserves translational invariance of the nuclear many-body problem. In this review, we, in particular, highlight results obtained with the chiral two- plus three-nucleon interactions. We discuss efforts to extend the applicability of the NCSM to heavier nuclei and larger model spaces using importance-truncation schemes and/or use of effective interactions with a core. We outline an extension of the ab initio NCSM to the description of nuclear reactions by the resonating group method technique. A future direction of the approach, the ab initio NCSM with continuum, which will provide a complete description of nuclei as open systems with coupling of bound and continuum states is given in the concluding part of the review.

  8. A Variational Model for Bent-Core Liquid Crystals

    E-Print Network [OSTI]

    2007-05-17

    THE 3RD SYMPOSIUM ON ANALYSIS AND PDES. PURDUE UNIVERSITY, MAY 27–30, 2007. A VARIATIONAL MODEL FOR BENT-CORE LIQUID CRYSTALS.

  9. Core melt/coolant interactions: modelling. [PWR; BWR

    SciTech Connect (OSTI)

    Berman, M.; McGlaun, J.M.; Corradini, M.L.

    1983-01-01

    If there is not adequate cooling water in the core of a light-water reactor (LWR), the fission product decay heat would eventually cause the reactor fuel and cladding to melt. This could lead to slumping of the molten core materials into the lower plenum of the reactor vessel, possibly followed by failure of the vessel wall and pouring of the molten materials into the reactor cavity. When the molten core materials enter either region, there is a strong possibility of molten core contacting water. This paper focuses on analysis of recent FITS experiments, mechanistic and probabilistic model development, and the application of these models to reactor considerations.

  10. A Semi-Analytic dynamical friction model that reproduces core stalling

    E-Print Network [OSTI]

    Petts, James A; Read, Justin I

    2015-01-01

    We present a new semi-analytic model for dynamical friction based on Chandrasekhar's formalism. The key novelty is the introduction of physically motivated, radially varying, maximum and minimum impact parameters. With these, our model gives an excellent match to full N-body simulations for isotropic background density distributions, both cuspy and shallow, without any fine-tuning of the model parameters. In particular, we are able to reproduce the dramatic core-stalling effect that occurs in shallow/constant density cores, for the first time. This gives us new physical insight into the core-stalling phenomenon. We show that core stalling occurs in the limit in which the product of the Coulomb logarithm and the local fraction of stars with velocity lower than the infalling body tends to zero. For cuspy backgrounds, this occurs when the infalling mass approaches the enclosed background mass. For cored backgrounds, it occurs at larger distances from the centre, due to a combination of a rapidly increasing minim...

  11. SCDAP/RELAP5 Lower Core Plate Model

    SciTech Connect (OSTI)

    Coryell, Eric Wesley; Griffin, F. P.

    1999-10-01

    The SCDAP/RELAP5 computer code is a best-estimate analysis tool for performing nuclear reactor severe accident simulations. This report describes the justification, theory, implementation, and testing of a new modeling capability which will refine the analysis of the movement of molten material from the core region to the vessel lower head. As molten material moves from the core region through the core support structures it may encounter conditions which will cause it to freeze in the region of the lower core plate, delaying its arrival to the vessel head. The timing of this arrival is significant to reactor safety, because during the time span for material relocation to the lower head, the core may be experiencing steam-limited oxidation. The time at which hot material arrives in a coolant-filled lower vessel head, thereby significantly increasing the steam flow rate through the core region, becomes significant to the progression and timing of a severe accident. This report is a revision of a report INEEL/EXT-00707, entitled "Preliminary Design Report for SCDAP/RELAP5 Lower Core Plate Model".

  12. SCDAP/RELAP5 lower core plate model

    SciTech Connect (OSTI)

    Coryell, E.W.; Griffin, F.P.

    1999-09-01

    The SCDAP/RELAP5 computer code is a best-estimate analysis tool for performing nuclear reactor severe accident simulations. This report describes the justification, theory, implementation, and testing of a new modeling capability which will refine the analysis of the movement of molten material from the core region to the vessel lower head. As molten material moves from the core region through the core support structures it may encounter conditions which will cause it to freeze in the region of the lower core plate, delaying its arrival to the vessel head. The timing of this arrival is significant to reactor safety, because during the time span for material relocation to the lower head, the core may be experiencing steam-limited oxidation. The time at which hot material arrives in a coolant-filled lower vessel head, thereby significantly increasing the steam flow rate through the core region, becomes significant to the progression and timing of a severe accident. This report is a revision of a report INEEL/EXT-00707, entitled ``Preliminary Design Report for SCDAP/RELAP5 Lower Core Plate Model''.

  13. Summary of multi-core hardware and programming model investigations

    SciTech Connect (OSTI)

    Kelly, Suzanne Marie; Pedretti, Kevin Thomas Tauke; Levenhagen, Michael J.

    2008-05-01

    This report summarizes our investigations into multi-core processors and programming models for parallel scientific applications. The motivation for this study was to better understand the landscape of multi-core hardware, future trends, and the implications on system software for capability supercomputers. The results of this study are being used as input into the design of a new open-source light-weight kernel operating system being targeted at future capability supercomputers made up of multi-core processors. A goal of this effort is to create an agile system that is able to adapt to and efficiently support whatever multi-core hardware and programming models gain acceptance by the community.

  14. Core-level satellites and outer core-level multiplet splitting in Mn model compounds

    SciTech Connect (OSTI)

    Nelson, A. J. [Lawrence Livermore National Laboratory, University of California, Livermore, California 94550 (United States)] [Lawrence Livermore National Laboratory, University of California, Livermore, California 94550 (United States); Reynolds, John G. [Lawrence Livermore National Laboratory, University of California, Livermore, California 94550 (United States)] [Lawrence Livermore National Laboratory, University of California, Livermore, California 94550 (United States); Roos, Joseph W. [Ethyl Corporation, Richmond, Virginia 23217 (United States)] [Ethyl Corporation, Richmond, Virginia 23217 (United States)

    2000-07-01

    We report a systematic study of the Mn 2p, 3s, and 3p core-level photoemission and satellite structures for Mn model compounds. Charge transfer from the ligand state to the 3d metal state is observed and is distinguished by prominent shake-up satellites. We also observe that the Mn 3s multiplet splitting becomes smaller as the Mn oxidation state increases, and that 3s-3d electron correlation reduces the branching ratio of the {sup 7}S:{sup 5}S states in the Mn 3s spectra. In addition, as the ligand electronegativity decreases, the spin-state purity is lost in the 3s spectra, as evidenced by peak broadening. Our results are best understood in terms of the configuration-interaction model including intrashell electron correlation, charge transfer, and final-state screening. (c) 2000 American Vacuum Society.

  15. Modeling Climate and Production-related Impacts on Ice-core Beryllium-10

    E-Print Network [OSTI]

    Modeling Climate and Production-related Impacts on Ice-core Beryllium-10 Christy Veeder Submitted Modeling Climate and Production-related Impacts on Ice-core Beryllium-10 Christy Veeder I use the Goddard Institute for Space Studies ModelE general circulation model to ex- amine the how beryllium-10, a cosmogenic

  16. A vectorized heat transfer model for solid reactor cores

    SciTech Connect (OSTI)

    Rider, W.J.; Cappiello, M.W.; Liles, D.R.

    1990-01-01

    The new generation of nuclear reactors includes designs that are significantly different from light water reactors. Among these new reactor designs is the Modular High-Temperature Gas-Cooled Reactor (MHTGR). In addition, nuclear thermal rockets share a number of similarities with terrestrial HTGRs and would be amenable to similar types of analyses. In these reactors, the heat transfer in the solid core mass is of primary interest in design and safety assessment. One significant safety feature of these reactors is the capability to withstand a loss of pressure and forced cooling in the primary system and still maintain peak fuel temperatures below the safe threshold for retaining the fission products. To accurately assess the performance of gas-cooled reactors during these types of transients, a Helium/Hydrogen Cooled Reactor Analysis (HERA) computer code has been developed. HERA has the ability to model arbitrary geometries in three dimensions, which allows the user to easily analyze reactor cores constructed of prismatic graphite elements. The code accounts for heat generation in the fuel, control rods and other structures; conduction and radiation across gaps; convection to the coolant; and a variety of boundary conditions. The numerical solution scheme has been optimized for vector computers, making long transient analyses economical. Time integration is either explicit or implicit, which allows the use of the model to accurately calculate both short- or long-term transients with an efficient use of computer time. Both the basic spatial and temporal integration schemes have been benchmarked against analytical solutions. Also, HERA has been used to analyze a depressurized loss of forced cooling transient in a HTGR with a very detailed three-dimensional input model. The results compare favorably with other means of analysis and provide further validation of the models and methods. 18 refs., 11 figs.

  17. Advanced Test Reactor Core Modeling Update Project Annual Report for Fiscal Year 2011

    SciTech Connect (OSTI)

    David W. Nigg; Devin A. Steuhm

    2011-09-01

    Legacy computational reactor physics software tools and protocols currently used for support of Advanced Test Reactor (ATR) core fuel management and safety assurance and, to some extent, experiment management are obsolete, inconsistent with the state of modern nuclear engineering practice, and are becoming increasingly difficult to properly verify and validate (V&V). Furthermore, the legacy staff knowledge required for application of these tools and protocols from the 1960s and 1970s is rapidly being lost due to staff turnover and retirements. In 2009 the Idaho National Laboratory (INL) initiated a focused effort to address this situation through the introduction of modern high-fidelity computational software and protocols, with appropriate V&V, within the next 3-4 years via the ATR Core Modeling and Simulation and V&V Update (or 'Core Modeling Update') Project. This aggressive computational and experimental campaign will have a broad strategic impact on the operation of the ATR, both in terms of improved computational efficiency and accuracy for support of ongoing DOE programs as well as in terms of national and international recognition of the ATR National Scientific User Facility (NSUF). The ATR Core Modeling Update Project, targeted for full implementation in phase with the anticipated ATR Core Internals Changeout (CIC) in the 2014 time frame, began during the last quarter of Fiscal Year 2009, and has just completed its first full year. Key accomplishments so far have encompassed both computational as well as experimental work. A new suite of stochastic and deterministic transport theory based reactor physics codes and their supporting nuclear data libraries (SCALE, KENO-6, HELIOS, NEWT, and ATTILA) have been installed at the INL under various permanent sitewide license agreements and corresponding baseline models of the ATR and ATRC are now operational, demonstrating the basic feasibility of these code packages for their intended purpose. Furthermore, a capability for rigorous sensitivity analysis and uncertainty quantification based on the TSUNAMI system is being implemented and initial computational results have been obtained. This capability will have many applications in 2011 and beyond as a tool for understanding the margins of uncertainty in the new models as well as for validation experiment design and interpretation. Finally we note that although full implementation of the new computational models and protocols will extend over a period 3-4 years as noted above, interim applications in the much nearer term have already been demonstrated. In particular, these demonstrations included an analysis that was useful for understanding the cause of some issues in December 2009 that were triggered by a larger than acceptable discrepancy between the measured excess core reactivity and a calculated value that was based on the legacy computational methods. As the Modeling Update project proceeds we anticipate further such interim, informal, applications in parallel with formal qualification of the system under the applicable INL Quality Assurance procedures and standards.

  18. A simple model for induction core voltage distributions

    E-Print Network [OSTI]

    Briggs, Richard J.; Fawley, William M.

    2004-01-01

    3 Electric fields around Metglas-mylar interface where •-,gaps between the four Metglas induction cores is veryare composed of 4"-wide Metglas tapewith anorrinal thickness

  19. A Dynamic Solar Core model: the SSM-like solution

    E-Print Network [OSTI]

    Attila Grandpierre

    1998-08-31

    I point out that the all the arguments against an astrophysical solution do not exclude a yet not recognised class of solar models, in which an explosive energy source is present in the solar core besides the standard pp and CNO cycle. It is shown from first principle physics that stars have a non-pp,CNO source: local thermonuclear runaways. I derive a model independent inequality, which shows that the problem of the missing beryllium neutrinos lies in that the SuperKamiokande contains a term arising from neutrinos from a runaway source which can produce high-energy electrons and high-energy axions, and muon and tau neutrinos. I point out, that the temperature dependence of the individual neutrino fluxes is related to pure nuclear physics but the usual luminosity constraint is model dependent and actually is a questionable assumption. Allowing non-pp,CNO reaction chains a new approach arises to interpret the neutrino detector data. The explicit temperature dependence leads to $\\Phi_{pp} \\propto T^4$ instead of the usual $\\Phi_{pp} \\propto T^{-1/2}$ for the SSM luminosity constraint. I assume a Sun analogue to the SSM with a different $T_c$. The separate neutrino detector equations lead to separate detector-related temperatures with the neutrino detector data. The results show a slightly lower than standard central temperature. I attempt to show that helioseismology is not in a necessary conflict with the dynamic solar model presented here. The results of the calculations may propose solutions to the problems of solar and atmospheric neutrino oscillations without an ad hoc introduction of sterile neutrinos and present predictions to Borexino and SNO measurements. {\\it PACS numbers}: 26.65+t, 26.30.+k, 96.60Jw, 95.30.Cq

  20. Architecture-level Thermal Behavioral Models For Quad-Core Microprocessors

    E-Print Network [OSTI]

    Tan, Sheldon X.-D.

    and architecture design of multi-core microprocessor. The estimated temperature at the architecture level can tools for thermal architecture modeling. Ex- isting work on the HotSpot project [8, 12] tried to resolve model- ing approach for fast temperature estimation at the quad- core thermal architecture level

  1. Continuously Optimized Reliable Energy (CORE) Microgrid: Models & Tools (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2013-07-01

    This brochure describes Continuously Optimized Reliable Energy (CORE), a trademarked process NREL employs to produce conceptual microgrid designs. This systems-based process enables designs to be optimized for economic value, energy surety, and sustainability. Capabilities NREL offers in support of microgrid design are explained.

  2. A simple model of cooling neutron stars with superfluid cores: comparison with observations

    E-Print Network [OSTI]

    A simple model of cooling neutron stars with superfluid cores: comparison with observations K.­Petersburg, Russia \\Lambday Abstract Cooling of neutron stars (NSs) with superfluid cores is simulated taking into account neutrino emission pro­ duced by Cooper pairing of nucleons. Two cooling regimes of NSs composed

  3. SAPHIR: a physiome core model of body fluid homeostasis and blood pressure regulation

    E-Print Network [OSTI]

    Fontecave-Jallon, Julie

    in different organs/tissues/cells at many different scales. The STEP1 Roadmap (see Fenner et al. 2008 in the STEP Roadmap is the development of `core models'. In the interest of providing a context

  4. Ab Initio Study of 40Ca with an Importance Truncated No-Core Shell Model

    SciTech Connect (OSTI)

    Roth, R; Navratil, P

    2007-05-22

    We propose an importance truncation scheme for the no-core shell model, which enables converged calculations for nuclei well beyond the p-shell. It is based on an a priori measure for the importance of individual basis states constructed by means of many-body perturbation theory. Only the physically relevant states of the no-core model space are considered, which leads to a dramatic reduction of the basis dimension. We analyze the validity and efficiency of this truncation scheme using different realistic nucleon-nucleon interactions and compare to conventional no-core shell model calculations for {sup 4}He and {sup 16}O. Then, we present the first converged calculations for the ground state of {sup 40}Ca within no-core model spaces including up to 16{h_bar}{Omega}-excitations using realistic low-momentum interactions. The scheme is universal and can be easily applied to other quantum many-body problems.

  5. Modeling percolation in high-aspect-ratio fiber systems. I. Soft-core versus hard-core models L. Berhan1,

    E-Print Network [OSTI]

    Sastry, Ann Marie

    . Indeed, experimental findings in nanotube- reinforced polymeric 1­11 and ceramic 12 matrix mate- rials in nanotubes-reinforced composites. The hard-core model can also potentially be used as a tool in calculating the tunneling distance in composite materials, given the fiber morphology and experimentally derived electrical

  6. Modeling of the Reactor Core Isolation Cooling Reposnse to Beyond Design Basis Operations - Interim Report

    SciTech Connect (OSTI)

    Ross, Kyle; Cardoni, Jeffrey N.; Wilson, Chisom Shawn; Morrow, Charles; Osborn, Douglas; Gauntt, Randall O.

    2015-12-01

    Efforts are being pursued to develop and qualify a system-level model of a reactor core isolation (RCIC) steam-turbine-driven pump. The model is being developed with the intent of employing it to inform the design of experimental configurations for full-scale RCIC testing. The model is expected to be especially valuable in sizing equipment needed in the testing. An additional intent is to use the model in understanding more fully how RCIC apparently managed to operate far removed from its design envelope in the Fukushima Daiichi Unit 2 accident. RCIC modeling is proceeding along two avenues that are expected to complement each other well. The first avenue is the continued development of the system-level RCIC model that will serve in simulating a full reactor system or full experimental configuration of which a RCIC system is part. The model reasonably represents a RCIC system today, especially given design operating conditions, but lacks specifics that are likely important in representing the off-design conditions a RCIC system might experience in an emergency situation such as a loss of all electrical power. A known specific lacking in the system model, for example, is the efficiency at which a flashing slug of water (as opposed to a concentrated jet of steam) could propel the rotating drive wheel of a RCIC turbine. To address this specific, the second avenue is being pursued wherein computational fluid dynamics (CFD) analyses of such a jet are being carried out. The results of the CFD analyses will thus complement and inform the system modeling. The system modeling will, in turn, complement the CFD analysis by providing the system information needed to impose appropriate boundary conditions on the CFD simulations. The system model will be used to inform the selection of configurations and equipment best suitable of supporting planned RCIC experimental testing. Preliminary investigations with the RCIC model indicate that liquid water ingestion by the turbine decreases the developed turbine torque; the RCIC speed then slows, and thus the pump flow rate to the RPV decreases. Subsequently, RPV water level decreases due to continued boiling and the liquid fraction flowing to the RCIC decreases, thereby accelerating the RCIC and refilling the RPV. The feedback cycle then repeats itself and/or reaches a quasi-steady equilibrium condition. In other words, the water carry-over is limited by cyclic RCIC performance degradation, and hence the system becomes self-regulating. The indications achieved to date with the system model are more qualitative than quantitative. The avenues being pursued to increase the fidelity of the model are expected to add quantitative realism. The end product will be generic in the sense that the RCIC model will be incorporable within the larger reactor coolant system model of any nuclear power plant or experimental configuration. ACKNOWLEDGEMENTS This work is funded through the U.S. Department of Energy - Office of Nuclear Energy's Light Water Reactor Sustainability Program. Clinton Smith of Phoenix Analysis & Design Technologies (PADT) is acknowledged for providing assistance on the FLUENT efforts in this report, as well as modifying the geometry model of the Terry turbine to make it more amenable for FLUENT analysis with rotating reference frames.

  7. Modeling production and climate-related impacts on Be concentration in ice cores

    E-Print Network [OSTI]

    strength and the solar activity modulation parameter (f), CO2, sea surface temperatures, and volcanic for studying changes in solar output. However, interpreting 10 Be ice core records on centennial timescales. By using the Goddard Institute for Space Studies ModelE general circulation model to selectively vary

  8. A NEW MULTI-DIMENSIONAL GENERAL RELATIVISTIC NEUTRINO HYDRODYNAMICS CODE FOR CORE-COLLAPSE SUPERNOVAE. II. RELATIVISTIC EXPLOSION MODELS OF CORE-COLLAPSE SUPERNOVAE

    SciTech Connect (OSTI)

    Mueller, Bernhard; Janka, Hans-Thomas; Marek, Andreas, E-mail: bjmuellr@mpa-garching.mpg.de, E-mail: thj@mpa-garching.mpg.de [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Str. 1, D-85748 Garching (Germany)

    2012-09-01

    We present the first two-dimensional general relativistic (GR) simulations of stellar core collapse and explosion with the COCONUT hydrodynamics code in combination with the VERTEX solver for energy-dependent, three-flavor neutrino transport, using the extended conformal flatness condition for approximating the space-time metric and a ray-by-ray-plus ansatz to tackle the multi-dimensionality of the transport. For both of the investigated 11.2 and 15 M{sub Sun} progenitors we obtain successful, though seemingly marginal, neutrino-driven supernova explosions. This outcome and the time evolution of the models basically agree with results previously obtained with the PROMETHEUS hydro solver including an approximative treatment of relativistic effects by a modified Newtonian potential. However, GR models exhibit subtle differences in the neutrinospheric conditions compared with Newtonian and pseudo-Newtonian simulations. These differences lead to significantly higher luminosities and mean energies of the radiated electron neutrinos and antineutrinos and therefore to larger energy-deposition rates and heating efficiencies in the gain layer with favorable consequences for strong nonradial mass motions and ultimately for an explosion. Moreover, energy transfer to the stellar medium around the neutrinospheres through nucleon recoil in scattering reactions of heavy-lepton neutrinos also enhances the mentioned effects. Together with previous pseudo-Newtonian models, the presented relativistic calculations suggest that the treatment of gravity and energy-exchanging neutrino interactions can make differences of even 50%-100% in some quantities and is likely to contribute to a finally successful explosion mechanism on no minor level than hydrodynamical differences between different dimensions.

  9. State space modeling of reactor core in a pressurized water reactor

    SciTech Connect (OSTI)

    Ashaari, A.; Ahmad, T.; M, Wan Munirah W.; Shamsuddin, Mustaffa; Abdullah, M. Adib

    2014-07-10

    The power control system of a nuclear reactor is the key system that ensures a safe operation for a nuclear power plant. However, a mathematical model of a nuclear power plant is in the form of nonlinear process and time dependent that give very hard to be described. One of the important components of a Pressurized Water Reactor is the Reactor core. The aim of this study is to analyze the performance of power produced from a reactor core using temperature of the moderator as an input. Mathematical representation of the state space model of the reactor core control system is presented and analyzed in this paper. The data and parameters are taken from a real time VVER-type Pressurized Water Reactor and will be verified using Matlab and Simulink. Based on the simulation conducted, the results show that the temperature of the moderator plays an important role in determining the power of reactor core.

  10. Reliability of Coupled Oscillators II: Larger Networks

    E-Print Network [OSTI]

    Kevin K. Lin; Eric Shea-Brown; Lai-Sang Young

    2007-08-23

    We study the reliability of phase oscillator networks in response to fluctuating inputs. Reliability means that an input elicits essentially identical responses upon repeated presentations, regardless of the network's initial condition. In this paper, we extend previous results on two-cell networks to larger systems. The first issue that arises is chaos in the absence of inputs, which we demonstrate and interpret in terms of reliability. We give a mathematical analysis of networks that can be decomposed into modules connected by an acyclic graph. For this class of networks, we show how to localize the source of unreliability, and address questions concerning downstream propagation of unreliability once it is produced.

  11. The Physics of Low Energy Solar "Today neutrinos have a larger and larger place in

    E-Print Network [OSTI]

    Chapter 1 The Physics of Low Energy Solar Neutrinos "Today neutrinos have a larger and larger place oscillations could na¨ively be 1 #12;Chapter 1: The Physics of Low Energy Solar Neutrinos 2 accommodated simply of Low Energy Solar Neutrinos 3 first directly detected more than two decades later in 1953. Reines

  12. A Bridging Model for Multi-Core Computing Leslie G. Valianta,,1

    E-Print Network [OSTI]

    , and would form the basis for implementation or compilation for particular machines. Our Multi-BSP model, and comparison sorting, there exist optimal portable algorithms in that sense, for all combinations of machine words: parallel algorithms, multi-core, bridging model, bulk synchronous. 1. Introduction Multi

  13. Ex-Vessel Core Melt Modeling Comparison between MELTSPREAD-CORQUENCH and MELCOR 2.1

    SciTech Connect (OSTI)

    Robb, Kevin R.; Farmer, Mitchell; Francis, Matthew W.

    2014-03-01

    System-level code analyses by both United States and international researchers predict major core melting, bottom head failure, and corium-concrete interaction for Fukushima Daiichi Unit 1 (1F1). Although system codes such as MELCOR and MAAP are capable of capturing a wide range of accident phenomena, they currently do not contain detailed models for evaluating some ex-vessel core melt behavior. However, specialized codes containing more detailed modeling are available for melt spreading such as MELTSPREAD as well as long-term molten corium-concrete interaction (MCCI) and debris coolability such as CORQUENCH. In a preceding study, Enhanced Ex-Vessel Analysis for Fukushima Daiichi Unit 1: Melt Spreading and Core-Concrete Interaction Analyses with MELTSPREAD and CORQUENCH, the MELTSPREAD-CORQUENCH codes predicted the 1F1 core melt readily cooled in contrast to predictions by MELCOR. The user community has taken notice and is in the process of updating their systems codes; specifically MAAP and MELCOR, to improve and reduce conservatism in their ex-vessel core melt models. This report investigates why the MELCOR v2.1 code, compared to the MELTSPREAD and CORQUENCH 3.03 codes, yield differing predictions of ex-vessel melt progression. To accomplish this, the differences in the treatment of the ex-vessel melt with respect to melt spreading and long-term coolability are examined. The differences in modeling approaches are summarized, and a comparison of example code predictions is provided.

  14. Downward transference of mice and universality of local core models

    E-Print Network [OSTI]

    Caicedo, Andres

    2012-01-01

    If M is an inner model and omega_2^M=omega_2, then every sound mouse projecting to omega and not past 0-pistol belongs to M. In fact, under the assumption that 0-pistol does not belong to M, K^M \\| omega_2 is universal for all countable mice in V}. Similarly, if delta>omega_1 is regular, (delta^+)^M = delta^+, and in V there is no proper class inner model with a Woodin cardinal, then K^M \\| delta is universal for all mice in V of cardinality less than delta.

  15. NIR imaging and modeling of the core of M100

    E-Print Network [OSTI]

    J. H. Knapen; R. F. Peletier; I. Shlosman; J. E. Beckman; C. H. Heller; R. S. de Jong

    1995-09-29

    High-resolution NIR and optical images are used to constrain a dynamical model of the circumnuclear star forming (SF) region in the barred galaxy M100 (=NGC 4321). Subarcsecond resolution allowed us to distinguish important morphological details which are easily misinterpreted when using images at lower resolution. Small leading arms observed in our K-band image of the nuclear region are reproduced in the gas flow in our model, and lead us to believe that part of the K light comes from young stars, which trace the gas flow.

  16. Contribution to modeling of the reflooding of a severely damaged reactor core using PRELUDE experimental results

    SciTech Connect (OSTI)

    Bachrata, A.; Fichot, F.; Repetto, G. [Institut de Radioprotection et de Surete Nucleaire IRSN, Cadarache (France); Quintard, M. [Universite de Toulouse, INPT, UPS, IMFT Institut de Mecanique des Fluides de Toulouse, Allee Camille Soula, F-31400 Toulouse (France); CNRS, IMFT, F-31400 Toulouse (France); Fleurot, J. [Institut de Radioprotection et de Surete Nucleaire IRSN, Cadarache (France)

    2012-07-01

    In case of accident at a nuclear power plant, water sources may not be available for a long period of time and the core heats up due to the residual power. The reflooding (injection of water into core) may be applied if the availability of safety injection is recovered during accident. If the injection becomes available only in the late phase of accident, water will enter a core configuration that will differ significantly from original rod-bundle geometry. Any attempt to inject water after significant core degradation can lead to further fragmentation of core material. The fragmentation of fuel rods may result in the formation of a 'debris bed'. The typical particle size in a debris bed might reach few millimeters (characteristic length-scale: 1 to 5 mm), i.e., a high permeability porous medium. The French 'Institut de Radioprotection et de Surete Nucleaire' is developing experimental programs (PEARL and PRELUDE) and simulation tools (ICARE-CATHARE and ASTEC) to study and optimize the severe accident management strategy and to assess the probabilities to stop the progress of in-vessel core degradation. It is shown that the quench front exhibits either a ID behaviour or a 2D one, depending on injection rate or bed characteristics. The PRELUDE experiment covers a rather large range of variation of parameters, for which the developed model appears to be quite predictive. (authors)

  17. Are Models for Core-Collapse Supernova Progenitors Consistent with the Properties of Supernova Remnants?

    E-Print Network [OSTI]

    Patnaude, Daniel J; Slane, Patrick O; Badenes, Carles; Heger, Alexander; Ellison, Donald C; Nagataki, Shigehiro

    2015-01-01

    The recent discovery that the Fe-K line luminosities and energy centroids observed in nearby SNRs are a strong discriminant of both progenitor type and circumstellar environment has implications for our understanding of supernova progenitor evolution. Using models for the chemical composition of core-collapse supernova ejecta, we model the dynamics and thermal X-ray emission from shocked ejecta and circumstellar material, modeled as an $r^{-2}$ wind, to ages of 3000 years. We compare the X-ray spectra expected from these models to observations made with the Suzaku satellite. We also model the dynamics and X-ray emission from Type Ia progenitor models. We find a clear distinction in Fe-K line energy centroid between core-collapse and Type Ia models. The core-collapse supernova models predict higher Fe-K line centroid energies than the Type Ia models, in agreement with observations. We argue that the higher line centroids are a consequence of the increased densities found in the circumstellar environment create...

  18. A Dynamic Solar Core Model: the Deviant Temperatures Approach

    E-Print Network [OSTI]

    Attila Grandpierre

    1998-08-31

    I derive here a model independent inequality which shows that the problem of the missing beryllium neutrinos of the Sun roots in the fact that the SuperKamiokande contains a term arising from a non-pp,CNO source. First principle physics shows that the non-pp,CNO source is of thermonuclear runaway origin. Several indications suggest that the non-pp,CNO term plays a more significant role in the solar neutrino problems than neutrino oscillations. When removing the over-restricted SSM luminosity constraint, the temperature dependence of the neutrino fluxes is related to pure nuclear physics and follows $\\Phi_{pp} \\propto T^4$ instead of $\\Phi_{pp} \\propto T^{-1/2}$. The results of the calculations offer solutions to the solar neutrino problems and problems of neutrino oscillations. The dynamic solar model presents predictions to Borexino and SNO measurements. These predictions can serve to distinguish between the MSW and the non-pp,CNO effect. {\\it PACS numbers|: 26.65.+t, 26.30.+k, 96.60.JW, 95.30.Cq

  19. Senior Design Projects 2013 Project Title 1 : Monte Carlo Simulations Using a Benchmark Full-Core Pressured Water Rector Model

    E-Print Network [OSTI]

    Danon, Yaron

    -Core Pressured Water Rector Model Advisor: Prof. X. George Xu (JEC 5003; Tel: 518-276-4014; Email: xug2@rpi in the design and analysis of nuclear reactor systems. One of the most desirable modeling and simulation a full-core PWR reactor model for parallel MCNP calculations on the CCNI system 4. Code optimization

  20. CPT: An Energy-Efficiency Model for Multi-core Computer Systems

    E-Print Network [OSTI]

    Shi, Weisong

    CPT: An Energy-Efficiency Model for Multi-core Computer Systems Weisong Shi, Shinan Wang and Bing efficiency of computer systems. These techniques affect the energy efficiency across different layers metric that represents the energy efficiency of a computer system, for a specific configuration, given

  1. Massive Neutron Stars with Hadron-Quark Transition Core : phenomenological approach by "3-window model"

    E-Print Network [OSTI]

    Tatsuyuki Takatsuka; Kota Masuda; Tetsuo Hatsuda

    2015-12-28

    By a new approach introducing a "3-window model" and constructing phenomenologically an equation of state for the hadron-quark (HQ) transition region, possible maximum mass of neutron stars (NSs) is discussed. It is found that neutron stars (NSs) with HQ transition core are able to have a mass exceeding two-solar mass, consistent with massive NSs recently observed.

  2. Development of high frequency spice models for ferrite core inductors and transformers

    SciTech Connect (OSTI)

    Muyshondt, G.P.; Portnoy, W.M. . Dept. of Electrical Engineering)

    1989-01-01

    In this work high frequency SPICE models were developed to simulate the hysteresis and saturation effects of toroidal shaped ferrite core inductors and transformers. The models include the nonlinear, multi-valued B-H characteristic of the core material, leakage flux, stray capacitances, and core losses. The saturation effects were modeled using two diode clamping arrangements in conjunction with nonlinear dependent sources. Two possible controlling schemes were developed for the saturation switch. One of the arrangements used the current flowing through a series RC branch to control the switch, while the other used a NAND gate. The NAND gate implementation of the switch proved to be simpler and the parameters associated with it were easier to determine from the measurements and the B-H characteristics of the material. Lumped parameters were used to simulate the parasitic effects. Techniques for measuring these parasitic are described. The models were verified using manganese-zinc ferrite-type toroidal cores and they have general applicability to all circuit analysis codes equivalent function blocks such as multipliers, adders, and logic components. 7 refs., 22 figs.

  3. A Dynamic Solar Core Model: On the Activity-Related Changes of the Neutrino Fluxes

    E-Print Network [OSTI]

    Attila Grandpierre

    1998-10-08

    The energy sources of the Sun may actually involve a thermonuclear runaway energy source present in stellar energy producing regions. I consider the conjectures of the derived model for the solar neutrino fluxes in case of a solar core allowed to vary in relation to the surface activity cycle. The observed neutrino flux data suggest a solar core possibly varying in time. In the dynamic solar model the quiet and runaway energy sources together may produce quasi-constant flux in the SuperKamiokande because it is sensitive to neutral currents, axions and anti-neutrinos, too. I calculate the contributions of the runaway source to the individual neutrino detectors. The results of the dynamic solar core model suggest that since the HOMESTAKE detects mostly the high energy electron neutrinos, therefore the HOMESTAKE data may aniticorrelate with the activity cycle. Activity correlated changes are expected to be present only marginally in the GALLEX and GNO data. The gallium detectors are sensitive mostly to the pp neutrinos, and the changes of the pp neutrinos arising from the SSM-like core is mostly compensated by the high-energy electron neutrinos produced by the hot bubbles of the dynamic energy source. The results suggest that the GALLEX data may show an anti-correlation, while the SuperKamiokande data may show a correlation with the activity cycle. Predictions of the dynamic solar model are presented for the SNO and Borexino experiments which can distinguish between the effects of the MSW mechanism and the consequences of the dynamic solar model. The results of the dynamic solar model are consistent with the present heioseismic measurements and can be checked with future heioseismic measurements as well. Keywords: solar neutrino problems - solar activity - thermonuclear runaways

  4. Long- and short-range correlations in the ab-initio no-core shell model

    E-Print Network [OSTI]

    Ionel Stetcu; Bruce R. Barrett; Petr Navratil; James P. Vary

    2006-01-25

    In the framework of the ab-initio no-core shell model (NCSM), we describe the longitudinal-longitudinal distribution function, part of the inclusive (e,e') longitudinal response. In the two-body cluster approximation, we compute the effective operators consistent with the unitary transformation used to obtain the effective Hamiltonian. When short-range correlations are probed, the results display independence from the model space size and length scale. Long-range correlations are more difficult to model in the NCSM and they can be described only by increasing the model space or increasing the cluster size. In order to illustrate the model space independence for short-range observables, we present results for a large set of model spaces for 4He, and in 0-4hw model spaces for 12C.

  5. Upcoming Funding Opportunity to Develop Larger Wind Turbine Blades...

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

    Upcoming Funding Opportunity to Develop Larger Wind Turbine Blades Upcoming Funding Opportunity to Develop Larger Wind Turbine Blades February 20, 2015 - 4:55pm Addthis On February...

  6. Failure Predictions for VHTR Core Components using a Probabilistic Contiuum Damage Mechanics Model

    SciTech Connect (OSTI)

    Fok, Alex

    2013-10-30

    The proposed work addresses the key research need for the development of constitutive models and overall failure models for graphite and high temperature structural materials, with the long-term goal being to maximize the design life of the Next Generation Nuclear Plant (NGNP). To this end, the capability of a Continuum Damage Mechanics (CDM) model, which has been used successfully for modeling fracture of virgin graphite, will be extended as a predictive and design tool for the core components of the very high- temperature reactor (VHTR). Specifically, irradiation and environmental effects pertinent to the VHTR will be incorporated into the model to allow fracture of graphite and ceramic components under in-reactor conditions to be modeled explicitly using the finite element method. The model uses a combined stress-based and fracture mechanics-based failure criterion, so it can simulate both the initiation and propagation of cracks. Modern imaging techniques, such as x-ray computed tomography and digital image correlation, will be used during material testing to help define the baseline material damage parameters. Monte Carlo analysis will be performed to address inherent variations in material properties, the aim being to reduce the arbitrariness and uncertainties associated with the current statistical approach. The results can potentially contribute to the current development of American Society of Mechanical Engineers (ASME) codes for the design and construction of VHTR core components.

  7. NUMERICAL VERIFICATION OF THE RELAP-7 CORE CHANNEL SINGLE-PHASE MODEL

    SciTech Connect (OSTI)

    Haihua Zhao; Ling Zou; Hongbin Zhang; Richard Martineau

    2014-06-01

    The RELAP-7 code is the next generation of nuclear reactor system safety analysis code being developed at the Idaho National Laboratory (INL). All the physics in RELAP-7 are fully coupled and the errors resulted from the traditional operator-splitting approach are eliminated. By using 2nd order methods in both time and space and eliminating operator-splitting errors, the numerical error of RELAP-7 can be minimized. Numerical verification is the process to verify the orders of numerical methods. It is an important part of modern verification and validation process. The core channel component in RELAP-7 is designed to simulate coolant flow as well as the conjugated heat transfer between coolant flow and the fuel rod. A special treatment at fuel centerline to avoid numerical singularity for the cylindrical heat conduction in the continuous finite element mesh is discussed. One steady state test case and one fast power up transient test case are utilized for the verification of the core channel model with single-phase flow. Analytical solution for the fuel pin temperature and figures of merit such as peak clad temperature and peak fuel temperature are used to define numerical errors. These cases prove that the mass and energy are well conserved and 2nd order convergence rates for both time and space are achieved in the core channel model.

  8. Advanced Test Reactor Core Modeling Update Project Annual Report for Fiscal Year 2010

    SciTech Connect (OSTI)

    Rahmat Aryaeinejad; Douglas S. Crawford; Mark D. DeHart; George W. Griffith; D. Scott Lucas; Joseph W. Nielsen; David W. Nigg; James R. Parry; Jorge Navarro

    2010-09-01

    Legacy computational reactor physics software tools and protocols currently used for support of Advanced Test Reactor (ATR) core fuel management and safety assurance and, to some extent, experiment management are obsolete, inconsistent with the state of modern nuclear engineering practice, and are becoming increasingly difficult to properly verify and validate (V&V). Furthermore, the legacy staff knowledge required for application of these tools and protocols from the 1960s and 1970s is rapidly being lost due to staff turnover and retirements. In 2009 the Idaho National Laboratory (INL) initiated a focused effort to address this situation through the introduction of modern high-fidelity computational software and protocols, with appropriate V&V, within the next 3-4 years via the ATR Core Modeling and Simulation and V&V Update (or “Core Modeling Update”) Project. This aggressive computational and experimental campaign will have a broad strategic impact on the operation of the ATR, both in terms of improved computational efficiency and accuracy for support of ongoing DOE programs as well as in terms of national and international recognition of the ATR National Scientific User Facility (NSUF).

  9. The treatment of mixing in core helium burning models: I. Implications for asteroseismology

    E-Print Network [OSTI]

    Constantino, Thomas; Christensen-Dalsgaard, Joergen; Lattanzio, John C; Stello, Dennis

    2015-01-01

    The detection of mixed oscillation modes offers a unique insight into the internal structure of core helium burning (CHeB) stars. The stellar structure during CHeB is very uncertain because the growth of the convective core, and/or the development of a semiconvection zone, is critically dependent on the treatment of convective boundaries. In this study we calculate a suite of stellar structure models and their non-radial pulsations to investigate why the predicted asymptotic g-mode $\\ell = 1$ period spacing $\\Delta\\Pi_1$ is systematically lower than is inferred from Kepler field stars. We find that only models with large convective cores, such as those calculated with our newly proposed "maximal-overshoot" scheme, can match the average $\\Delta\\Pi_1$ reported. However, we also find another possible solution that is related to the method used to determine $\\Delta\\Pi_1$: mode trapping can raise the observationally inferred $\\Delta\\Pi_1$ well above its true value. Even after accounting for these two proposed reso...

  10. TRACE/PARCS Core Modeling of a BWR/5 for Accident Analysis of ATWS Events

    SciTech Connect (OSTI)

    Cuadra A.; Baek J.; Cheng, L.; Aronson, A.; Diamond, D.; Yarsky, P.

    2013-11-10

    The TRACE/PARCS computational package [1, 2] isdesigned to be applicable to the analysis of light water reactor operational transients and accidents where the coupling between the neutron kinetics (PARCS) and the thermal-hydraulics and thermal-mechanics (TRACE) is important. TRACE/PARCS has been assessed for itsapplicability to anticipated transients without scram(ATWS) [3]. The challenge, addressed in this study, is to develop a sufficiently rigorous input model that would be acceptable for use in ATWS analysis. Two types of ATWS events were of interest, a turbine trip and a closure of main steam isolation valves (MSIVs). In the first type, initiated by turbine trip, the concern is that the core will become unstable and large power oscillations will occur. In the second type,initiated by MSIV closure,, the concern is the amount of energy being placed into containment and the resulting emergency depressurization. Two separate TRACE/PARCS models of a BWR/5 were developed to analyze these ATWS events at MELLLA+ (maximum extended load line limit plus)operating conditions. One model [4] was used for analysis of ATWS events leading to instability (ATWS-I);the other [5] for ATWS events leading to emergency depressurization (ATWS-ED). Both models included a large portion of the nuclear steam supply system and controls, and a detailed core model, presented henceforth.

  11. Modeling of BWR core meltdown accidents - for application in the MELRPI. MOD2 computer code

    SciTech Connect (OSTI)

    Koh, B R; Kim, S H; Taleyarkhan, R P; Podowski, M Z; Lahey, Jr, R T

    1985-04-01

    This report summarizes improvements and modifications made in the MELRPI computer code. A major difference between this new, updated version of the code, called MELRPI.MOD2, and the one reported previously, concerns the inclusion of a model for the BWR emergency core cooling systems (ECCS). This model and its computer implementation, the ECCRPI subroutine, account for various emergency injection modes, for both intact and rubblized geometries. Other changes to MELRPI deal with an improved model for canister wall oxidation, rubble bed modeling, and numerical integration of system equations. A complete documentation of the entire MELRPI.MOD2 code is also given, including an input guide, list of subroutines, sample input/output and program listing.

  12. A moist aquaplanet variant of the Held–Suarez test for atmospheric model dynamical cores

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

    Thatcher, D. R.; Jablonowski, C.

    2015-09-29

    A moist idealized test case (MITC) for atmospheric model dynamical cores is presented. The MITC is based on the Held–Suarez (HS) test that was developed for dry simulations on a flat Earth and replaces the full physical parameterization package with a Newtonian temperature relaxation and Rayleigh damping of the low-level winds. This new variant of the HS test includes moisture and thereby sheds light on the non-linear dynamics-physics moisture feedbacks without the complexity of full physics parameterization packages. In particular, it adds simplified moist processes to the HS forcing to model large-scale condensation, boundary layer mixing, and the exchange ofmore »latent and sensible heat between the atmospheric surface and an ocean-covered planet. Using a variety of dynamical cores of NCAR's Community Atmosphere Model (CAM), this paper demonstrates that the inclusion of the moist idealized physics package leads to climatic states that closely resemble aquaplanet simulations with complex physical parameterizations. This establishes that the MITC approach generates reasonable atmospheric circulations and can be used for a broad range of scientific investigations. This paper provides examples of two application areas. First, the test case reveals the characteristics of the physics-dynamics coupling technique and reproduces coupling issues seen in full-physics simulations. In particular, it is shown that sudden adjustments of the prognostic fields due to moist physics tendencies can trigger undesirable large-scale gravity waves, which can be remedied by a more gradual application of the physical forcing. Second, the moist idealized test case can be used to intercompare dynamical cores. These examples demonstrate the versatility of the MITC approach and suggestions are made for further application areas. The new moist variant of the HS test can be considered a test case of intermediate complexity.« less

  13. Modeling Stress Strain Relationships and Predicting Failure Probabilities For Graphite Core Components

    SciTech Connect (OSTI)

    Duffy, Stephen

    2013-09-09

    This project will implement inelastic constitutive models that will yield the requisite stress-strain information necessary for graphite component design. Accurate knowledge of stress states (both elastic and inelastic) is required to assess how close a nuclear core component is to failure. Strain states are needed to assess deformations in order to ascertain serviceability issues relating to failure, e.g., whether too much shrinkage has taken place for the core to function properly. Failure probabilities, as opposed to safety factors, are required in order to capture the bariability in failure strength in tensile regimes. The current stress state is used to predict the probability of failure. Stochastic failure models will be developed that can accommodate possible material anisotropy. This work will also model material damage (i.e., degradation of mechanical properties) due to radiation exposure. The team will design tools for components fabricated from nuclear graphite. These tools must readily interact with finite element software--in particular, COMSOL, the software algorithm currently being utilized by the Idaho National Laboratory. For the eleastic response of graphite, the team will adopt anisotropic stress-strain relationships available in COMSO. Data from the literature will be utilized to characterize the appropriate elastic material constants.

  14. NON-EQUILIBRIUM CHEMISTRY OF DYNAMICALLY EVOLVING PRESTELLAR CORES. I. BASIC MAGNETIC AND NON-MAGNETIC MODELS AND PARAMETER STUDIES

    SciTech Connect (OSTI)

    Tassis, Konstantinos; Willacy, Karen; Yorke, Harold W.; Turner, Neal J. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

    2012-07-01

    We combine dynamical and non-equilibrium chemical modeling of evolving prestellar molecular cloud cores and investigate the evolution of molecular abundances in the contracting core. We model both magnetic cores, with varying degrees of initial magnetic support, and non-magnetic cores, with varying collapse delay times. We explore, through a parameter study, the competing effects of various model parameters in the evolving molecular abundances, including the elemental C/O ratio, the temperature, and the cosmic-ray ionization rate. We find that different models show their largest quantitative differences at the center of the core, whereas the outer layers, which evolve slower, have abundances which are severely degenerate among different dynamical models. There is a large range of possible abundance values for different models at a fixed evolutionary stage (central density), which demonstrates the large potential of chemical differentiation in prestellar cores. However, degeneracies among different models, compounded with uncertainties induced by other model parameters, make it difficult to discriminate among dynamical models. To address these difficulties, we identify abundance ratios between particular molecules, the measurement of which would have maximal potential for discrimination among the different models examined here. In particular, we find that the ratios between NH{sub 3} and CO, NH{sub 2} and CO, and NH{sub 3} and HCO{sup +} are sensitive to the evolutionary timescale, and that the ratio between HCN and OH is sensitive to the C/O ratio. Finally, we demonstrate that measurements of the central deviation (central depletion or enhancement) of abundances of certain molecules are good indicators of the dynamics of the core.

  15. New Report Shows Trend Toward Larger Offshore Wind Systems, with...

    Office of Environmental Management (EM)

    New Report Shows Trend Toward Larger Offshore Wind Systems, with 11 Advanced Stage Projects Proposed in U.S. Waters New Report Shows Trend Toward Larger Offshore Wind Systems, with...

  16. New Report Shows Trend Toward Larger Offshore Wind Systems, with...

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

    Report Shows Trend Toward Larger Offshore Wind Systems, with 11 Advanced Stage Projects Proposed in U.S. Waters New Report Shows Trend Toward Larger Offshore Wind Systems, with 11...

  17. Inference of ICF implosion core mix using experimental data and theoretical mix modeling

    SciTech Connect (OSTI)

    Sherrill, Leslie Welser [Los Alamos National Laboratory; Haynes, Donald A [Los Alamos National Laboratory; Cooley, James H [Los Alamos National Laboratory; Sherrill, Manolo E [Los Alamos National Laboratory; Mancini, Roberto C [UNR; Tommasini, Riccardo [LLNL; Golovkin, Igor E [PRISM COMP. SCIENCES; Haan, Steven W [LLNL

    2009-01-01

    The mixing between fuel and shell materials in Inertial Confinement Fusion (lCF) implosion cores is a current topic of interest. The goal of this work was to design direct-drive ICF experiments which have varying levels of mix, and subsequently to extract information on mixing directly from the experimental data using spectroscopic techniques. The experimental design was accomplished using hydrodynamic simulations in conjunction with Haan's saturation model, which was used to predict the mix levels of candidate experimental configurations. These theoretical predictions were then compared to the mixing information which was extracted from the experimental data, and it was found that Haan's mix model predicted trends in the width of the mix layer as a function of initial shell thickness. These results contribute to an assessment of the range of validity and predictive capability of the Haan saturation model, as well as increasing confidence in the methods used to extract mixing information from experimental data.

  18. Advanced Test Reactor Core Modeling Update Project Annual Report for Fiscal Year 2012

    SciTech Connect (OSTI)

    David W. Nigg, Principal Investigator; Kevin A. Steuhm, Project Manager

    2012-09-01

    Legacy computational reactor physics software tools and protocols currently used for support of Advanced Test Reactor (ATR) core fuel management and safety assurance, and to some extent, experiment management, are inconsistent with the state of modern nuclear engineering practice, and are difficult, if not impossible, to properly verify and validate (V&V) according to modern standards. Furthermore, the legacy staff knowledge required for application of these tools and protocols from the 1960s and 1970s is rapidly being lost due to staff turnover and retirements. In late 2009, the Idaho National Laboratory (INL) initiated a focused effort, the ATR Core Modeling Update Project, to address this situation through the introduction of modern high-fidelity computational software and protocols. This aggressive computational and experimental campaign will have a broad strategic impact on the operation of the ATR, both in terms of improved computational efficiency and accuracy for support of ongoing DOE programs as well as in terms of national and international recognition of the ATR National Scientific User Facility (NSUF). The ATR Core Modeling Update Project, targeted for full implementation in phase with the next anticipated ATR Core Internals Changeout (CIC) in the 2014-2015 time frame, began during the last quarter of Fiscal Year 2009, and has just completed its third full year. Key accomplishments so far have encompassed both computational as well as experimental work. A new suite of stochastic and deterministic transport theory based reactor physics codes and their supporting nuclear data libraries (HELIOS, KENO6/SCALE, NEWT/SCALE, ATTILA, and an extended implementation of MCNP5) has been installed at the INL under various licensing arrangements. Corresponding models of the ATR and ATRC are now operational with all five codes, demonstrating the basic feasibility of the new code packages for their intended purpose. Of particular importance, a set of as-run core depletion HELIOS calculations for all ATR cycles since August 2009, Cycle 145A through Cycle 151B, was successfully completed during 2012. This major effort supported a decision late in the year to proceed with the phased incorporation of the HELIOS methodology into the ATR Core Safety Analysis Package (CSAP) preparation process, in parallel with the established PDQ-based methodology, beginning late in Fiscal Year 2012. Acquisition of the advanced SERPENT (VTT-Finland) and MC21 (DOE-NR) Monte Carlo stochastic neutronics simulation codes was also initiated during the year and some initial applications of SERPENT to ATRC experiment analysis were demonstrated. These two new codes will offer significant additional capability, including the possibility of full-3D Monte Carlo fuel management support capabilities for the ATR at some point in the future. Finally, a capability for rigorous sensitivity analysis and uncertainty quantification based on the TSUNAMI system has been implemented and initial computational results have been obtained. This capability will have many applications as a tool for understanding the margins of uncertainty in the new models as well as for validation experiment design and interpretation.

  19. Modeling the ratios of SKKS and SKS amplitudes with ultra-low velocity zones at the core-mantle boundary

    E-Print Network [OSTI]

    Ritsema, Jeroen

    Modeling the ratios of SKKS and SKS amplitudes with ultra-low velocity zones at the core of earthquakes in Indonesia. Modeling of SKKS/SKS indicate that Ultra-Low Velocity Zones (ULVZs), layers, and M. S. Thorne (2009), Modeling the ratios of SKKS and SKS amplitudes with ultra-low velocity zones

  20. Effect of a detailed radial core expansion reactivity feedback model on ATWS calculations using SASSYS/SAS4A

    SciTech Connect (OSTI)

    Wigeland, R.A.

    1986-01-01

    The present emphasis on inherent safety and inherently safe designs for liquid-metal reactors has resulted in a need to represent the various reactivity feedback mechanisms as accurately as possible. In particular, the reactivity feedback from radial core expansion has been found to provide the dominant negative feedback contribution in postulated anticipated transient without scram (ATWS) events. Review of the existing modeling in the SASSYS/SAS4A computer code system revealed that while the modeling may be adequate for the early phases of various unprotected transients, the accuracy would be less than desirable for the extended transients which typically occur for inherently safe designs. The existing model for calculating the reactivity feedback from radial core expansion uses a feedback from radial core expansion uses a feedback coefficient in conjunction with changes in the temperatures of the grid support plate and the above-core load pad. The accuracy of this approach is determined partly by the conditions used in deriving the feedback coefficient, and their relevance to the transient being investigated. Accuracy is also affected by the need to include effects other than those that could be directly related to changes in the grid plate and above-core load pad temperatures, such as subassembly bowing and the potential for clearances to occur between subassemblies in the above-core load pad region. As a result, a detailed model was developed in an attempt to account for these and other effects in a more mechanistic form.

  1. Effective operators within the ab initio no-core shell model

    E-Print Network [OSTI]

    Ionel Stetcu; Bruce R. Barrett; Petr Navratil; James P. Vary

    2005-03-19

    We implement an effective operator formalism for general one- and two-body operators, obtaining results consistent with the no-core shell model (NCSM) wave functions. The Argonne V8' nucleon-nucleon potential was used in order to obtain realistic wave functions for 4He, 6Li and 12C. In the NCSM formalism, we compute electromagnetic properties using the two-body cluster approximation for the effective operators and obtain results which are sensitive to the range of the bare operator. To illuminate the dependence on the range, we employ a Gaussian two-body operator of variable range, finding weak renormalization of long range operators (e.g., quadrupole) in a fixed model space. This is understood in terms of the two-body cluster approximation which accounts mainly for short-range correlations. Consequently, short range operators, such as the relative kinetic energy, will be well renormalized in the two-body cluster approximation.

  2. Advanced Test Reactor Core Modeling Update Project Annual Report for Fiscal Year 2013

    SciTech Connect (OSTI)

    David W. Nigg

    2013-09-01

    Legacy computational reactor physics software tools and protocols currently used for support of Advanced Test Reactor (ATR) core fuel management and safety assurance, and to some extent, experiment management, are inconsistent with the state of modern nuclear engineering practice, and are difficult, if not impossible, to verify and validate (V&V) according to modern standards. Furthermore, the legacy staff knowledge required for effective application of these tools and protocols from the 1960s and 1970s is rapidly being lost due to staff turnover and retirements. In late 2009, the Idaho National Laboratory (INL) initiated a focused effort, the ATR Core Modeling Update Project, to address this situation through the introduction of modern high-fidelity computational software and protocols. This aggressive computational and experimental campaign will have a broad strategic impact on the operation of the ATR, both in terms of improved computational efficiency and accuracy for support of ongoing DOE programs as well as in terms of national and international recognition of the ATR National Scientific User Facility (NSUF).

  3. Generic disposal concepts and thermal load management for larger...

    Office of Scientific and Technical Information (OSTI)

    Generic disposal concepts and thermal load management for larger waste packages. Citation Details In-Document Search Title: Generic disposal concepts and thermal load management...

  4. Scientists detect methane levels three times larger than expected...

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

    methane that actually preceded recent concerns about potential emissions from fracking," Dubey said. Scientists detect methane levels three times larger than expected over...

  5. Infrared length scale and extrapolations for the no-core shell model

    E-Print Network [OSTI]

    Wendt, K A; Papenbrock, T; Sääf, D

    2015-01-01

    We precisely determine the infrared (IR) length scale of the no-core shell model (NCSM). In the NCSM, the $A$-body Hilbert space is truncated by the total energy, and the IR length can be determined by equating the intrinsic kinetic energy of $A$ nucleons in the NCSM space to that of $A$ nucleons in a $3(A-1)$-dimensional hyper-radial well with a Dirichlet boundary condition for the hyper radius. We demonstrate that this procedure indeed yields a very precise IR length by performing large-scale NCSM calculations for $^{6}$Li. We apply our result and perform accurate IR extrapolations for bound states of $^{4}$He, $^{6}$He, $^{6}$Li, $^{7}$Li. We also attempt to extrapolate NCSM results for $^{10}$B and $^{16}$O with bare interactions from chiral effective field theory over tens of MeV.

  6. Ab Initio No Core Shell Model - Recent Results and Further Prospects

    E-Print Network [OSTI]

    James P. Vary; Pieter Maris; Hugh Potter; Mark A. Caprio; Robin Smith; Sven Binder; Angelo Calci; Sebastian Fischer; Joachim Langhammer; Robert Roth; Hasan Metin Aktulga; Esmond Ng; Chao Yang; Dossay Oryspayev; Masha Sosonkina; Erik Saule; Ümit Çatalyürek

    2015-07-16

    There has been significant recent progress in solving the long-standing problems of how nuclear shell structure and collective motion emerge from underlying microscopic inter-nucleon interactions. We review a selection of recent significant results within the ab initio No Core Shell Model (NCSM) closely tied to three major factors enabling this progress: (1) improved nuclear interactions that accurately describe the experimental two-nucleon and three-nucleon interaction data; (2) advances in algorithms to simulate the quantum many-body problem with strong interactions; and (3) continued rapid development of high-performance computers now capable of performing $20 \\times 10^{15}$ floating point operations per second. We also comment on prospects for further developments.

  7. Study of decoherence in models for hard-core bosons coupled to optical phonons

    E-Print Network [OSTI]

    A. Dey; M. Q. Lone; S. Yarlagadda

    2014-12-18

    Understanding coherent dynamics of excitons, spins, or hard-core bosons (HCBs) has tremendous scientific and technological implications for light harvesting and quantum computation. Here, we study decay of excited-state population and decoherence in two models for HCBs, namely: an infinite-range HCB model governed by Markovian dynamics and a two-site HCB model with site-dependent strong potentials and subject to non-Markovian dynamics. Both models are investigated in the regimes of antiadiabaticity and strong HCB-phonon coupling with each site providing a different local optical phonon environment; furthermore, the HCB systems in both models are taken to be initially uncorrelated with the environment in the polaronic frame of reference. For the infinite-range model, we derive an effective many-body Hamiltonian that commutes with the long-range system Hamiltonian and thus has the same set of eigenstates; consequently, a quantum-master-equation approach shows that the quantum states of the system do not decohere. In the case of the two-site HCB model, we show clearly that the degree of decoherence and decay of excited state are enhanced by the proximity of the site-energy difference to the eigenenergy of phonons and are most pronounced when the site-energy difference is at resonance with twice the polaronic energy; additionally, the decoherence and the decay effects are reduced when the strength of HCB-phonon coupling is increased. Even for a multimode situation, the degree of decoherence and decay are again dictated by the nearness of the energy difference to the allowed phonon mode eigenenergies.

  8. Origin of Macrostrains and Microstrains in Daimond-SiC Nanocomposites Based on the Core-shell Model

    SciTech Connect (OSTI)

    Palosz,B.; Stelmakh, S.; Grzanka, E.; Gierlotka, S.; Nauyoks, S.; Zerda, T.; Palosz, W.

    2007-01-01

    SiC-diamond nanocomposites were synthesized from nanodiamond and nanosilicon powders. A core-shell model of the composite nanocrystals was examined assuming that interatomic distances in the grain interior, the core, and at the surface shell (grain boundaries in nanocrystalline solids) are different. The samples were investigated by x-ray diffraction using synchrotron source. The powder diffractograms were elaborated based on the apparent lattice parameter methodology. The structure of the composites and its dependence on the sintering conditions is discussed. It is shown that as the sintering temperature increases the interatomic distances in the grain cores decrease, while the opposite occurs in the grain shells (forming the grain boundaries). Under some sintering temperature the interatomic distances in the core and in the shell get equal. However, for diamond this happens under different temperature than for SiC, thus internal strains in the composites are unavoidable.

  9. Percentage of Positive Biopsy Cores: A Better Risk Stratification Model for Prostate Cancer?

    SciTech Connect (OSTI)

    Huang Jiayi; Vicini, Frank A. [Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, MI (United States); Williams, Scott G. [Peter Maccallum Cancer Centre and University of Melbourne, Melbourne, Victoria (Australia); Ye Hong; McGrath, Samuel; Ghilezan, Mihai; Krauss, Daniel; Martinez, Alvaro A. [Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, MI (United States); Kestin, Larry L., E-mail: lkestin@comcast.net [Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, MI (United States)

    2012-07-15

    Purpose: To assess the prognostic value of the percentage of positive biopsy cores (PPC) and perineural invasion in predicting the clinical outcomes after radiotherapy (RT) for prostate cancer and to explore the possibilities to improve on existing risk-stratification models. Methods and Materials: Between 1993 and 2004, 1,056 patients with clinical Stage T1c-T3N0M0 prostate cancer, who had four or more biopsy cores sampled and complete biopsy core data available, were treated with external beam RT, with or without a high-dose-rate brachytherapy boost at William Beaumont Hospital. The median follow-up was 7.6 years. Multivariate Cox regression analysis was performed with PPC, Gleason score, pretreatment prostate-specific antigen, T stage, PNI, radiation dose, androgen deprivation, age, prostate-specific antigen frequency, and follow-up duration. A new risk stratification (PPC classification) was empirically devised to incorporate PPC and replace the T stage. Results: On multivariate Cox regression analysis, the PPC was an independent predictor of distant metastasis, cause-specific survival, and overall survival (all p < .05). A PPC >50% was associated with significantly greater distant metastasis (hazard ratio, 4.01; 95% confidence interval, 1.86-8.61), and its independent predictive value remained significant with or without androgen deprivation therapy (all p < .05). In contrast, PNI and T stage were only predictive for locoregional recurrence. Combining the PPC ({<=}50% vs. >50%) with National Comprehensive Cancer Network risk stratification demonstrated added prognostic value of distant metastasis for the intermediate-risk (hazard ratio, 5.44; 95% confidence interval, 1.78-16.6) and high-risk (hazard ratio, 4.39; 95% confidence interval, 1.70-11.3) groups, regardless of the use of androgen deprivation and high-dose RT (all p < .05). The proposed PPC classification appears to provide improved stratification of the clinical outcomes relative to the National Comprehensive Cancer Network classification. Conclusions: The PPC is an independent and powerful predictor of clinical outcomes of prostate cancer after RT. A risk model replacing T stage with the PPC to reduce subjectivity demonstrated potentially improved stratification.

  10. CORCON-MOD3: An integrated computer model for analysis of molten core-concrete interactions. User`s manual

    SciTech Connect (OSTI)

    Bradley, D.R.; Gardner, D.R.; Brockmann, J.E.; Griffith, R.O. [Sandia National Labs., Albuquerque, NM (United States)

    1993-10-01

    The CORCON-Mod3 computer code was developed to mechanistically model the important core-concrete interaction phenomena, including those phenomena relevant to the assessment of containment failure and radionuclide release. The code can be applied to a wide range of severe accident scenarios and reactor plants. The code represents the current state of the art for simulating core debris interactions with concrete. This document comprises the user`s manual and gives a brief description of the models and the assumptions and limitations in the code. Also discussed are the input parameters and the code output. Two sample problems are also given.

  11. Thermodynamics and Structural Properties of the High Density Gaussian Core Model

    E-Print Network [OSTI]

    Atsushi Ikeda; Kunimasa Miyazaki

    2011-07-20

    We numerically study thermodynamic and structural properties of the one-component Gaussian core model (GCM) at very high densities. The solid-fluid phase boundary is carefully determined. We find that the density dependence of both the freezing and melting temperatures obey the asymptotic relation, $\\log T_f$, $\\log T_m \\propto -\\rho^{2/3}$, where $\\rho$ is the number density, which is consistent with Stillinger's conjecture. Thermodynamic quantities such as the energy and pressure and the structural functions such as the static structure factor are also investigated in the fluid phase for a wide range of temperature above the phase boundary. We compare the numerical results with the prediction of the liquid theory with the random phase approximation (RPA). At high temperatures, the results are in almost perfect agreement with RPA for a wide range of density, as it has been already shown in the previous studies. In the low temperature regime close to the phase boundary line, although RPA fails to describe the structure factors and the radial distribution functions at the length scales of the interparticle distance, it successfully predicts their behaviors at shorter length scales. RPA also predicts thermodynamic quantities such as the energy, pressure, and the temperature at which the thermal expansion coefficient becomes negative, almost perfectly. Striking ability of RPA to predict thermodynamic quantities even at high densities and low temperatures is understood in terms of the decoupling of the length scales which dictate thermodynamic quantities from the interparticle distance which dominates the peak structures of the static structure factor due to the softness of the Gaussian core potential.

  12. Integrated Core-SOL-Divertor Modelling for ITER Including Impurity: Effect of Tungsten on Fusion Performance in H-mode and Hybrid Scenario

    E-Print Network [OSTI]

    Integrated Core-SOL-Divertor Modelling for ITER Including Impurity: Effect of Tungsten on Fusion Performance in H-mode and Hybrid Scenario

  13. Larger Black Flour Beetle in Southern High Plains Homes 

    E-Print Network [OSTI]

    Porter, Patrick; McIntyre, Nancy E.

    2007-04-09

    Larger black flour beetles have invaded homes and other buildings in some Southern High Plains counties in Texas. This publication explains how to identify the beetles, find and eliminate the source, and exclude the insects from the house....

  14. Developing Fully Coupled Dynamical Reactor Core Isolation System Models in RELAP-7 for Extended Station Black-Out Analysis

    SciTech Connect (OSTI)

    Haihua Zhao; Ling Zou; Hongbin Zhang; David Andrs; Richard Martineau

    2014-04-01

    The reactor core isolation cooling (RCIC) system in a boiling water reactor (BWR) provides makeup water to the reactor vessel for core cooling when the main steam lines are isolated and the normal supply of water to the reactor vessel is lost. It was one of the very few safety systems still available during the Fukushima Daiichi accidents after the tsunamis hit the plants and the system successfully delayed the core meltdown for a few days for unit 2 & 3. Therefore, detailed models for RCIC system components are indispensable to understand extended station black-out accidents (SBO) for BWRs. As part of the effort to develop the new generation reactor system safety analysis code RELAP-7, major components to simulate the RCIC system have been developed. This paper describes the models for those components such as turbine, pump, and wet well. Selected individual component test simulations and a simplified SBO simulation up to but before core damage is presented. The successful implementation of the simplified RCIC and wet well models paves the way to further improve the models for safety analysis by including more detailed physical processes in the near future.

  15. On the shape of core overshooting in stellar model computations, and asteroseismic tests

    E-Print Network [OSTI]

    Moravveji, Ehsan

    2015-01-01

    Slowly pulsating B stars (SPB) and $\\gamma$ Dor stars pulsate in high-order gravity (g-) modes. The frequencies of g-modes are sensitive to the detailed structure and evolution history of stars having convective cores. Receding convective cores in OB-type stars leave behind a chemically inhomogenous $\

  16. From non-Hermitian effective operators to large-scale no-core shell model calculations for light nuclei

    E-Print Network [OSTI]

    Bruce R. Barrett; Ionel Stetcu; Petr Navratil; James P. Vary

    2006-03-10

    No-core shell model (NCSM) calculations using ab initio effective interactions are very successful in reproducing experimental nuclear spectra. The main theoretical approach is the use of effective operators, which include correlations left out by the truncation of the model space to a numerically tractable size. We review recent applications of the effective operator approach, within a NCSM framework, to the renormalization of the nucleon-nucleon interaction, as well as scalar and tensor operators.

  17. Modeling analysis of core-shell Si/SiGe nanowires

    E-Print Network [OSTI]

    Tang, Ming Y., 1979-

    2004-01-01

    (cont.) a composition that results in a high mobility has a very promising thermoelectric performance. Lastly, the thermoelectric-related transport properties for a Si/SiGe core-shell nanowire are compared with the related ...

  18. Benchmark of Atucha-2 PHWR RELAP5-3D control rod model by Monte Carlo MCNP5 core calculation

    SciTech Connect (OSTI)

    Pecchia, M.; D'Auria, F.; Mazzantini, O.

    2012-07-01

    Atucha-2 is a Siemens-designed PHWR reactor under construction in the Republic of Argentina. Its geometrical complexity and peculiarities require the adoption of advanced Monte Carlo codes for performing realistic neutronic simulations. Therefore core models of Atucha-2 PHWR were developed using MCNP5. In this work a methodology was set up to collect the flux in the hexagonal mesh by which the Atucha-2 core is represented. The scope of this activity is to evaluate the effect of obliquely inserted control rod on neutron flux in order to validate the RELAP5-3D{sup C}/NESTLE three dimensional neutron kinetic coupled thermal-hydraulic model, applied by GRNSPG/UNIPI for performing selected transients of Chapter 15 FSAR of Atucha-2. (authors)

  19. A Real-Time Capable Many-Core Model Stefan Metzlaff, Jorg Mische, Theo Ungerer

    E-Print Network [OSTI]

    Ungerer, Theo

    of Computer Science University of Augsburg Augsburg, Germany {metzlaff architectures. We think that the usage of processors with high core numbers will also emerge in embedded real for embedded real-time systems: predictability, performance and energy efficiency. At first we enunciate a set

  20. Prediction Models for Multi-dimensional Power-Performance Optimization on Many Cores

    E-Print Network [OSTI]

    Nikolopoulos, Dimitris

    a primary concern for HPC systems. Dynamic voltage and frequency scaling (DVFS) and dynamic concurrency significant reductions in energy (19% mean) and ED2 (40% mean), through simultaneous power savings (6% mean by reducing contention between threads for shared resources such as memory bandwidth. Conserving cores

  1. Effect of attractive interactions on the water-like anomalies of a core-softened model potential

    SciTech Connect (OSTI)

    Pant, Shashank; Gera, Tarun; Choudhury, Niharendu E-mail: niharc2002@yahoo.com

    2013-12-28

    It is now well established that water-like anomalies can be reproduced by a spherically symmetric potential with two length scales, popularly known as core-softened potential. In the present study we aim to investigate the effect of attractive interactions among the particles in a model fluid interacting with core-softened potential on the existence and location of various water-like anomalies in the temperature-pressure plane. We employ extensive molecular dynamic simulations to study anomalous nature of various order parameters and properties under isothermal compression. Order map analyses have also been done for all the potentials. We observe that all the systems with varying depth of attractive wells show structural, dynamic, and thermodynamic anomalies. As many of the previous studies involving model water and a class of core softened potentials have concluded that the structural anomaly region encloses the diffusion anomaly region, which in turn, encloses the density anomaly region, the same pattern has also been observed in the present study for the systems with less depth of attractive well. For the systems with deeper attractive well, we observe that the diffusion anomaly region shifts toward higher densities and is not always enclosed by the structural anomaly region. Also, density anomaly region is not completely enclosed by diffusion anomaly region in this case.

  2. Growth of Smaller Grain Attached on Larger One: Algorithm to Overcome Unphysical Overlap between Grain

    E-Print Network [OSTI]

    Acep Purqon; Sparisoma Viridi

    2014-11-01

    As a smaller grain, which is attached on larger one, is growing, it pushes also the larger one and other grains in its surrounding. In a simulation of similar system, repulsive force such as contact force based on linear spring-dashpot model can not accommodate this situation when cell growing rate is faster than simulation time step, since it produces sudden large overlap between grains that makes unphysical result. An algorithm that preserves system linear momentum by introducing additional velocity induced by cell growth is presented in this work. It should be performed in an implicit step. The algorithm has successfully eliminated unphysical overlap.

  3. No-Core Shell Model Analysis Of Light Nuclei (Conference) | SciTech Connect

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTech Connect Nanomechanical switch for| SciTechPhaseNewton'sConference: No-Core Shell

  4. No-Core Shell Model Analysis Of Light Nuclei (Conference) | SciTech Connect

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTech Connect Nanomechanical switch for| SciTechPhaseNewton'sConference: No-Core

  5. Modeling of fuel-to-steel heat transfer in core disruptive accidents

    E-Print Network [OSTI]

    Smith, Russell Charles

    1980-01-01

    A mathematical model for direct-contact boiling heat transfer between immiscible fluids was developed and tested experimentally. The model describes heat transfer from a hot fluid bath to an ensemble of droplets of a cooler ...

  6. Properties of a soft-core model of methanol: An integral equation theory and computer simulation study

    SciTech Connect (OSTI)

    Huš, Matej; Urbic, Tomaz; Munaò, Gianmarco

    2014-10-28

    Thermodynamic and structural properties of a coarse-grained model of methanol are examined by Monte Carlo simulations and reference interaction site model (RISM) integral equation theory. Methanol particles are described as dimers formed from an apolar Lennard-Jones sphere, mimicking the methyl group, and a sphere with a core-softened potential as the hydroxyl group. Different closure approximations of the RISM theory are compared and discussed. The liquid structure of methanol is investigated by calculating site-site radial distribution functions and static structure factors for a wide range of temperatures and densities. Results obtained show a good agreement between RISM and Monte Carlo simulations. The phase behavior of methanol is investigated by employing different thermodynamic routes for the calculation of the RISM free energy, drawing gas-liquid coexistence curves that match the simulation data. Preliminary indications for a putative second critical point between two different liquid phases of methanol are also discussed.

  7. RECONCILING MODELS OF LUMINOUS BLAZARS WITH MAGNETIC FLUXES DETERMINED BY RADIO CORE-SHIFT MEASUREMENTS

    SciTech Connect (OSTI)

    Nalewajko, Krzysztof; Begelman, Mitchell C.; Sikora, Marek

    2014-11-20

    Estimates of magnetic field strength in relativistic jets of active galactic nuclei, obtained by measuring the frequency-dependent radio core location, imply that the total magnetic fluxes in those jets are consistent with the predictions of the magnetically arrested disk (MAD) scenario of jet formation. On the other hand, the magnetic field strength determines the luminosity of the synchrotron radiation, which forms the low-energy bump of the observed blazar spectral energy distribution (SED). The SEDs of the most powerful blazars are strongly dominated by the high-energy bump, which is most likely due to the external radiation Compton mechanism. This high Compton dominance may be difficult to reconcile with the MAD scenario, unless (1) the geometry of external radiation sources (broad-line region, hot-dust torus) is quasi-spherical rather than flat, or (2) most gamma-ray radiation is produced in jet regions of low magnetization, e.g., in magnetic reconnection layers or in fast jet spines.

  8. TWO-DIMENSIONAL CORE-COLLAPSE SUPERNOVA MODELS WITH MULTI-DIMENSIONAL...

    Office of Scientific and Technical Information (OSTI)

    diffusion (MGFLD) neutrino transport, including all relevant O(vc) terms. Our main motivation for carrying out this study is to compare with recent 2D models produced by other...

  9. Continuum-kinetic-microscopic model of lung clearance due to core-annular fluid entrainment

    E-Print Network [OSTI]

    Welch, Greg

    model of the effect of airflow shear forces, as exerted by tidal breathing and cough, upon clearance]. Upon breakdown of this healthy-state mucociliary transport mechanism, cough can clear mucus from

  10. Core Topography

    E-Print Network [OSTI]

    Carter-Thompson, Safiya

    2011-04-20

    Core Topography By Safiya Carter-Thompson Submitted to the graduate degree program in Design and the Graduate Faculty of the University of Kansas in partial fulfillment of the requirements for the degree of Master of Arts...-Thompson certifies that this is the approved version of the following thesis: Core Topography ________________________________ Chairperson Mary Anne Jordan Date approved: April 20 th 2011 iii...

  11. Core Analysis for the Development and Constraint of Physical Models of Geothermal Reservoirs

    SciTech Connect (OSTI)

    Greg N. Boitnott

    2003-12-14

    Effective reservoir exploration, characterization, and engineering require a fundamental understanding of the geophysical properties of reservoir rocks and fracture systems. Even in the best of circumstances, spatial variability in porosity, fracture density, salinity, saturation, tectonic stress, fluid pressures, and lithology can all potentially produce and/or contribute to geophysical anomalies. As a result, serious uniqueness problems frequently occur when interpreting assumptions based on a knowledge base founded in validated rock physics models of reservoir material.

  12. Continuum-kinetic-microscopic model of lung clearance due to core-annular fluid entrainment

    SciTech Connect (OSTI)

    Mitran, Sorin

    2013-07-01

    The human lung is protected against aspirated infectious and toxic agents by a thin liquid layer lining the interior of the airways. This airway surface liquid is a bilayer composed of a viscoelastic mucus layer supported by a fluid film known as the periciliary liquid. The viscoelastic behavior of the mucus layer is principally due to long-chain polymers known as mucins. The airway surface liquid is cleared from the lung by ciliary transport, surface tension gradients, and airflow shear forces. This work presents a multiscale model of the effect of airflow shear forces, as exerted by tidal breathing and cough, upon clearance. The composition of the mucus layer is complex and variable in time. To avoid the restrictions imposed by adopting a viscoelastic flow model of limited validity, a multiscale computational model is introduced in which the continuum-level properties of the airway surface liquid are determined by microscopic simulation of long-chain polymers. A bridge between microscopic and continuum levels is constructed through a kinetic-level probability density function describing polymer chain configurations. The overall multiscale framework is especially suited to biological problems due to the flexibility afforded in specifying microscopic constituents, and examining the effects of various constituents upon overall mucus transport at the continuum scale.

  13. Targeted transperineal biopsy of the prostate has limited additional benefit over background cores for larger MRI-identified tumors

    E-Print Network [OSTI]

    Barrett, Tristan; Patterson, Andrew J.; Koo, Brendan C.; Wadhwa, Karan; Warren, Anne Y.; Doble, Andrew; Gnanapragasam, Vincent J.; Kastner, Christof; Gallagher, Ferdia A.

    2015-01-01

    platform (Medcom, Darmstadt, Germany). Briefly, a transrectal ultrasound probe is inserted and mounted on a brachytherapy gantry with a template grid for transperineal needle placement in the prostate. MR images are co-registered to ultrasound images...

  14. MCNP LWR Core Generator

    SciTech Connect (OSTI)

    Fischer, Noah A.

    2012-08-14

    The reactor core input generator allows for MCNP input files to be tailored to design specifications and generated in seconds. Full reactor models can now easily be created by specifying a small set of parameters and generating an MCNP input for a full reactor core. Axial zoning of the core will allow for density variation in the fuel and moderator, with pin-by-pin fidelity, so that BWR cores can more accurately be modeled. LWR core work in progress: (1) Reflectivity option for specifying 1/4, 1/2, or full core simulation; (2) Axial zoning for moderator densities that vary with height; (3) Generating multiple types of assemblies for different fuel enrichments; and (4) Parameters for specifying BWR box walls. Fuel pin work in progress: (1) Radial and azimuthal zoning for generating further unique materials in fuel rods; (2) Options for specifying different types of fuel for MOX or multiple burn assemblies; (3) Additional options for replacing fuel rods with burnable poison rods; and (4) Control rod/blade modeling.

  15. Preliminary Study of Bypass Flow in Prismatic Core of Very High Temperature Reactor Using Small-Scale Model 

    E-Print Network [OSTI]

    Kanjanakijkasem, Worasit 1975-

    2012-11-29

    energy are: gas-cooled fast reactor (GFR); lead-cooled fast reactor (LFR); molten salt reactor (MSR); sodium-cooled fast reactor (SFR); supercritical water-cooled reactor (SCWR); and very high-temperature gas-cooled reactor (VHTR) [3]. These reactor...-temperature gas-cooled reactor (VHTR) is a graphite-moderated, helium-cooled, thermal neutron spectrum reactor with a once-through uranium fuel cycle [4]. The reactor core can be either a prismatic block or a pebble-bed core. The VHTR system is designed to be a...

  16. Disturbed core Undisturbed soil

    E-Print Network [OSTI]

    Pennycook, Steve

    Batch Disturbed core Undisturbed soil column Pedon Field Watershed Multi-scale modeling .001-1 m3 1-10 m3 10-10,000 m3 >10,000 m3 Unraveling the influence of scale on organic C transport Soil through deep soil profiles may be the "missing" C flux in global budgets. Jardine, P.M., M.A. Mayes, J. R

  17. Using CORE Model-Based Systems Engineering Software to Support Program Management in the U.S. Department of Energy Office of the Biomass Project: Preprint

    SciTech Connect (OSTI)

    Riley, C.; Sandor, D.; Simpkins, P.

    2006-11-01

    This paper describes how a model-based systems engineering software, CORE, is helping the U. S. Department of Energy's Office of Biomass Program assist with bringing biomass-derived biofuels to the market. This software tool provides information to guide informed decision-making as biomass-to-biofuels systems are advanced from concept to commercial adoption. It facilitates management and communication of program status by automatically generating custom reports, Gantt charts, and tables using the widely available programs of Microsoft Word, Project and Excel.

  18. Larger Teaching and Learning Development Projects Proposal Criteria (3 pages maximum)

    E-Print Network [OSTI]

    . A. Question(s) to be investigated. (Usually will be focused on student Larger Teaching and Learning Development Projects Proposal Criteria (3 learning) B. General Rationale and Description: Why is this question

  19. LARGER ITEMS Aquatic climbing wall for lake www.crs4rec.com

    E-Print Network [OSTI]

    Stuart, Steven J.

    LARGER ITEMS Aquatic climbing wall for lake www.crs4rec.com Oreck vacuum cleaners Household Carpet preferred) (60 or 75 watt) Extension cords (green; 15', 50' and 100') Dog food for the Outdoor Lab (Purina

  20. EARLIEST STAGES OF PROTOCLUSTER FORMATION: SUBSTRUCTURE AND KINEMATICS OF STARLESS CORES IN ORION

    SciTech Connect (OSTI)

    Lee, Katherine; Looney, Leslie W.; Schnee, Scott; Li Zhiyun

    2013-08-01

    We study the structure and kinematics of nine 0.1 pc scale cores in Orion with the IRAM 30 m telescope and at higher resolution eight of the cores with CARMA, using CS(2-1) as the main tracer. The single-dish moment zero maps of the starless cores show single structures with central column densities ranging from 7 to 42 Multiplication-Sign 10{sup 23} cm{sup -2} and LTE masses from 20 M{sub Sun} to 154 M{sub Sun }. However, at the higher CARMA resolution (5''), all of the cores except one fragment into 3-5 components. The number of fragments is small compared to that found in some turbulent fragmentation models, although inclusion of magnetic fields may reduce the predicted fragment number and improve the model agreement. This result demonstrates that fragmentation from parsec-scale molecular clouds to sub-parsec cores continues to take place inside the starless cores. The starless cores and their fragments are embedded in larger filamentary structures, which likely played a role in the core formation and fragmentation. Most cores show clear velocity gradients, with magnitudes ranging from 1.7 to 14.3 km s{sup -1} pc{sup -1}. We modeled one of them in detail, and found that its spectra are best explained by a converging flow along a filament toward the core center; the gradients in other cores may be modeled similarly. We infer a mass inflow rate of {approx}2 Multiplication-Sign 10{sup -3} M{sub Sun} yr{sup -1}, which is in principle high enough to overcome radiation pressure and allow for massive star formation. However, the core contains multiple fragments, and it is unclear whether the rapid inflow would feed the growth of primarily a single massive star or a cluster of lower mass objects. We conclude that fast, supersonic converging flow along filaments play an important role in massive star and cluster formation.

  1. Modeling, Characterization and Simulation of On-Chip Power Delivery Networks and Temperature Profile on Multi-Core Microprocessors

    E-Print Network [OSTI]

    Li, Duo

    2010-01-01

    The power grid model used. . . . . . . . . . . . . . . . . .143 xii List of Figures The power gridRealization for On-Chip Power Grid Network Analysis Power

  2. The non-linear health consequences of living in larger cities

    E-Print Network [OSTI]

    Rocha, Luis E C; Lambiotte, Renaud

    2015-01-01

    Urbanization promotes economy, mobility, access and availability of resources, but on the other hand, generates higher levels of pollution, violence, crime, and mental distress. The health consequences of the agglomeration of people living close together are not fully understood. Particularly, it remains unclear how variations in the population size across cities impact the health of the population. We analyze the deviations from linearity of the scaling of several health-related quantities, such as the incidence and mortality of diseases, external causes of death, wellbeing, and health-care availability, in respect to the population size of cities in Brazil, Sweden and the USA. We find that deaths by non-communicable diseases tend to be relatively less common in larger cities, whereas the per-capita incidence of infectious diseases is relatively larger for increasing population size. Healthier life style and availability of medical support are disproportionally higher in larger cities. The results are connec...

  3. Bent core liquid crystal elastomers

    SciTech Connect (OSTI)

    Verduzco, R.; DiMasi, E.; Luchette, P.; Ho Hong, S.; Harden, J.; Palffy-Muhoray, P.; Kilbey II, S.M.; Sprunt, S.; Gleeson, G.T. Jakli, A.

    2010-07-28

    Liquid crystal (LC) elastomers with bent-core side-groups incorporate the properties of bent-core liquid crystals in a flexible and self-supporting polymer network. Bent-core liquid crystal elastomers (BCEs) with uniform alignment were prepared by attaching a reactive bent-core LC to poly(hydrogenmethylsiloxane) and crosslinking with a divinyl crosslinker. Phase behavior studies indicate a nematic phase over a wide temperature range that approaches room temperature, and thermoelastic measurements show that these BCEs can reversibly change their length by more than a factor of two upon heating and cooling. Small-angle X-ray scattering studies reveal multiple, broad low-angle peaks consistent with short-range smectic C order of the bent-core side groups. A comparison of these patterns with predictions of a Landau model for short-range smectic C order shows that the length scale for smectic ordering in BCEs is similar to that seen in pure bent-core LCs. The combination of rubber elasticity and smectic ordering of the bent-core side groups suggests that BCEs may be promising materials for sensing, actuating, and other advanced applications.

  4. Multi-Group Formulation of the Temperature-Dependent Resonance Scattering Model and its Impact on Reactor Core Parameters

    SciTech Connect (OSTI)

    Ghrayeb, Shadi Z. [Pennsylvania State Univ., University Park, PA (United States). Dept. of Mechanical and Nuclear Engineering; Ougouag, Abderrafi M. [Idaho National Laboratory (INL), Idaho Falls, ID (United States); Ouisloumen, Mohamed [Westinghouse Electric Company, Cranberry Township, PA (United States); Ivanov, Kostadin N. [Pennsylvania State Univ., University Park, PA (United States). Dept. of Mechanical and Nuclear Engineering

    2014-01-01

    A multi-group formulation for the exact neutron elastic scattering kernel is developed. It incorporates the neutron up-scattering effects, stemming from lattice atoms thermal motion and accounts for it within the resulting effective nuclear cross-section data. The effects pertain essentially to resonant scattering off of heavy nuclei. The formulation, implemented into a standalone code, produces effective nuclear scattering data that are then supplied directly into the DRAGON lattice physics code where the effects on Doppler Reactivity and neutron flux are demonstrated. The correct accounting for the crystal lattice effects influences the estimated values for the probability of neutron absorption and scattering, which in turn affect the estimation of core reactivity and burnup characteristics. The results show an increase in values of Doppler temperature feedback coefficients up to -10% for UOX and MOX LWR fuels compared to the corresponding values derived using the traditional asymptotic elastic scattering kernel. This paper also summarizes the results done on this topic to date.

  5. Larger groups are more successful in innovative problem solving in house sparrows

    E-Print Network [OSTI]

    Indiana University

    Larger groups are more successful in innovative problem solving in house sparrows Andra´s Liker1 of opening a familiar feeder in an unfamiliar way to house sparrows in small and large groups (2 versus 6 in animals have long been the focus of behavioral ecological research. Although individuals in groups may

  6. PARTICLE IMAGE VELOCIMETRY MEASUREMENTS IN A REPRESENTATIVE GAS-COOLED PRISMATIC REACTOR CORE MODEL: FLOW IN THE COOLANT CHANNELS AND INTERSTITIAL BYPASS GAPS

    SciTech Connect (OSTI)

    Thomas E. Conder; Richard Skifton; Ralph Budwig

    2012-11-01

    Core bypass flow is one of the key issues with the prismatic Gas Turbine-Modular Helium Reactor, and it refers to the coolant that navigates through the interstitial, non-cooling passages between the graphite fuel blocks instead of traveling through the designated coolant channels. To determine the bypass flow, a double scale representative model was manufactured and installed in the Matched Index-of-Refraction flow facility; after which, stereo Particle Image Velocimetry (PIV) was employed to measure the flow field within. PIV images were analyzed to produce vector maps, and flow rates were calculated by numerically integrating over the velocity field. It was found that the bypass flow varied between 6.9-15.8% for channel Reynolds numbers of 1,746 and 4,618. The results were compared to computational fluid dynamic (CFD) pre-test simulations. When compared to these pretest calculations, the CFD analysis appeared to under predict the flow through the gap.

  7. Impacts of rotation on three-dimensional hydrodynamics of core-collapse supernovae

    SciTech Connect (OSTI)

    Nakamura, Ko; Kuroda, Takami; Kotake, Kei [Division of Theoretical Astronomy, National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Takiwaki, Tomoya [Center for Computational Astrophysics, National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)

    2014-09-20

    We perform a series of simplified numerical experiments to explore how rotation impacts the three-dimensional (3D) hydrodynamics of core-collapse supernovae. For our systematic study, we employ a light-bulb scheme to trigger explosions and a three-flavor neutrino leakage scheme to treat deleptonization effects and neutrino losses from the proto-neutron-star interior. Using a 15 M {sub ?} progenitor, we compute 30 models in 3D with a wide variety of initial angular momentum and light-bulb neutrino luminosity. We find that the rotation can help the onset of neutrino-driven explosions for the models in which the initial angular momentum is matched to that obtained in recent stellar evolutionary calculations (?0.3-3 rad s{sup –1} at the center). For the models with larger initial angular momentum, the shock surface deforms to be more oblate due to larger centrifugal force. This not only makes the gain region more concentrated around the equatorial plane, but also makes the mass larger in the gain region. As a result, buoyant bubbles tend to be coherently formed and rise in the equatorial region, which pushes the revived shock toward ever larger radii until a global explosion is triggered. We find that these are the main reasons that the preferred direction of the explosion in 3D rotating models is often perpendicular to the spin axis, which is in sharp contrast to the polar explosions around the axis that were obtained in previous two-dimensional simulations.

  8. Larger sized wire arrays on 1.5 MA Z-pinch generator

    SciTech Connect (OSTI)

    Safronova, A. S. Kantsyrev, V. L. Weller, M. E. Shlyaptseva, V. V. Shrestha, I. K. Esaulov, A. A. Stafford, A.; Chuvatin, A. S.; Coverdale, C. A.; Jones, B.

    2014-12-15

    Experiments on the UNR Zebra generator with Load Current Multiplier (LCM) allow for implosions of larger sized wire array loads than at standard current of 1 MA. Advantages of larger sized planar wire array implosions include enhanced energy coupling to plasmas, better diagnostic access to observable plasma regions, and more complex geometries of the wire loads. The experiments with larger sized wire arrays were performed on 1.5 MA Zebra with LCM (the anode-cathode gap was 1 cm, which is half the gap used in the standard mode). In particular, larger sized multi-planar wire arrays had two outer wire planes from mid-atomic-number wires to create a global magnetic field (gmf) and plasma flow between them. A modified central plane with a few Al wires at the edges was put in the middle between outer planes to influence gmf and to create Al plasma flow in the perpendicular direction (to the outer arrays plasma flow). Such modified plane has different number of empty slots: it was increased from 6 up to 10, hence increasing the gap inside the middle plane from 4.9 to 7.7 mm, respectively. Such load configuration allows for more independent study of the flows of L-shell mid-atomic-number plasma (between the outer planes) and K-shell Al plasma (which first fills the gap between the edge wires along the middle plane) and their radiation in space and time. We demonstrate that such configuration produces higher linear radiation yield and electron temperatures as well as advantages of better diagnostics access to observable plasma regions and how the load geometry (size of the gap in the middle plane) influences K-shell Al radiation. In particular, K-shell Al radiation was delayed compared to L-shell mid-atomic-number radiation when the gap in the middle plane was large enough (when the number of empty slots was increased up to ten)

  9. The Kinematics of Molecular Cloud Cores in the Presence of Driven and Decaying Turbulence: Comparisons with Observations

    SciTech Connect (OSTI)

    Offner, S R; Krumholz, M R; Klein, R I; McKee, C F

    2008-04-18

    In this study we investigate the formation and properties of prestellar and protostellar cores using hydrodynamic, self-gravitating Adaptive Mesh Refinement simulations, comparing the cases where turbulence is continually driven and where it is allowed to decay. We model observations of these cores in the C{sup 18}O(2 {yields} 1), NH{sub 3}(1,1), and N{sub 2}H{sup +} (1 {yields} 0) lines, and from the simulated observations we measure the linewidths of individual cores, the linewidths of the surrounding gas, and the motions of the cores relative to one another. Some of these distributions are significantly different in the driven and decaying runs, making them potential diagnostics for determining whether the turbulence in observed star-forming clouds is driven or decaying. Comparing our simulations with observed cores in the Perseus and {rho} Ophiuchus clouds shows reasonably good agreement between the observed and simulated core-to-core velocity dispersions for both the driven and decaying cases. However, we find that the linewidths through protostellar cores in both simulations are too large compared to the observations. The disagreement is noticeably worse for the decaying simulation, in which cores show highly supersonic infall signatures in their centers that decrease toward their edges, a pattern not seen in the observed regions. This result gives some support to the use of driven turbulence for modeling regions of star formation, but reaching a firm conclusion on the relative merits of driven or decaying turbulence will require more complete data on a larger sample of clouds as well as simulations that include magnetic fields, outflows, and thermal feedback from the protostars.

  10. CORE SHAPES AND ORIENTATIONS OF CORE-SÉRSIC GALAXIES

    SciTech Connect (OSTI)

    Dullo, Bililign T.; Graham, Alister W., E-mail: Bdullo@astro.swin.edu.au [Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Hawthorn, Victoria 3122 (Australia)

    2015-01-01

    The inner and outer shapes and orientations of core-Sérsic galaxies may hold important clues to their formation and evolution. We have therefore measured the central and outer ellipticities and position angles for a sample of 24 core-Sérsic galaxies using archival Hubble Space Telescope (HST) images and data. By selecting galaxies with core-Sérsic break radii R{sub b} —a measure of the size of their partially depleted core—that are ? 0.''2, we find that the ellipticities and position angles are quite robust against HST seeing. For the bulk of the galaxies, there is a good agreement between the ellipticities and position angles at the break radii and the average outer ellipticities and position angles determined over R {sub e}/2 < R < R {sub e}, where R {sub e} is the spheroids' effective half light radius. However there are some interesting differences. We find a median ''inner'' ellipticity at R{sub b} of ?{sub med} = 0.13 ± 0.01, rounder than the median ellipticity of the ''outer'' regions ?{sub med} = 0.20 ± 0.01, which is thought to reflect the influence of the central supermassive black hole at small radii. In addition, for the first time we find a trend, albeit weak (2? significance), such that galaxies with larger (stellar deficit-to-supermassive black hole) mass ratios—thought to be a measure of the number of major dry merger events—tend to have rounder inner and outer isophotes, suggesting a connection between the galaxy shapes and their merger histories. We show that this finding is not simply reflecting the well known result that more luminous galaxies are rounder, but it is no doubt related.

  11. Core Drilling Demonstration

    Broader source: Energy.gov [DOE]

    Tank Farms workers demonstrate core drilling capabilities for Hanford single-shell tanks. Core drilling is used to determine the current condition of each tank to assist in the overall assessment...

  12. FISSION REACTORS KEYWORDS: core-barrel vibra-

    E-Print Network [OSTI]

    Demazière, Christophe

    FISSION REACTORS KEYWORDS: core-barrel vibra- tions, in-core neutron noise, shell- mode vibrations-REGION SLAB REACTOR MODEL CARL SUNDE,* CHRISTOPHE DEMAZIÈRE, and IMRE PÁZSIT Chalmers University of Technology. 5 gives a self-contained description of the principles of fluctuation analysis for the diagnostics

  13. Grain alignment in starless cores

    SciTech Connect (OSTI)

    Jones, T. J.; Bagley, M. [Minnesota Institute for Astrophysics, University of Minnesota, Minneapolis, MN 55455 (United States); Krejny, M. [Cree Inc., 4600 Silicon Dr., Durham, NC (United States); Andersson, B.-G. [SOFIA Science Center, USRA, Moffett Field, CA (United States); Bastien, P., E-mail: tjj@astro.umn.edu [Centre de recherche en astrophysique du Québec and Départment de Physique, Université de Montréal, Montréal (Canada)

    2015-01-01

    We present near-IR polarimetry data of background stars shining through a selection of starless cores taken in the K band, probing visual extinctions up to A{sub V}?48. We find that P{sub K}/?{sub K} continues to decline with increasing A{sub V} with a power law slope of roughly ?0.5. Examination of published submillimeter (submm) polarimetry of starless cores suggests that by A{sub V}?20 the slope for P versus ? becomes ??1, indicating no grain alignment at greater optical depths. Combining these two data sets, we find good evidence that, in the absence of a central illuminating source, the dust grains in dense molecular cloud cores with no internal radiation source cease to become aligned with the local magnetic field at optical depths greater than A{sub V}?20. A simple model relating the alignment efficiency to the optical depth into the cloud reproduces the observations well.

  14. HTTF Core Stress Analysis

    SciTech Connect (OSTI)

    Brian D. Hawkes; Richard Schultz

    2012-07-01

    In accordance with the need to determine whether cracking of the ceramic core disks which will be constructed and used in the High Temperature Test Facility (HTTF) for heatup and cooldown experiments, a set of calculation were performed using Abaqus to investigate the thermal stresses levels and likelihood for cracking. The calculations showed that using the material properties provided for the Greencast 94F ceramic, cracking is predicted to occur. However, this modeling does not predict the size or length of the actual cracks. It is quite likely that cracks will be narrow with rough walls which would impede the flow of coolant gases entering the cracks. Based on data recorded at Oregon State University using Greencast 94F samples that were heated and cooled at prescribed rates, it was concluded that the likelihood that the cracks would be detrimental to the experimental objectives is small.

  15. The compactness of presupernova stellar cores

    SciTech Connect (OSTI)

    Sukhbold, Tuguldur; Woosley, S. E., E-mail: sukhbold@ucolick.org [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)

    2014-03-01

    The success or failure of the neutrino-transport mechanism for producing a supernova in an evolved massive star is known to be sensitive not only to the mass of the iron core that collapses, but also to the density gradient in the silicon and oxygen shells surrounding that core. Here we study the systematics of a presupernova core's 'compactness' as a function of the mass of the star and the physics used in its calculation. Fine-meshed surveys of presupernova evolution are calculated for stars from 15 to 65 M {sub ?}. The metallicity and the efficiency of semiconvection and overshoot mixing are both varied and bare carbon-oxygen cores are explored as well as full hydrogenic stars. Two different codes, KEPLER and MESA, are used for the study. A complex interplay of carbon and oxygen burning, especially in shells, can cause rapid variations in the compactness for stars of very nearly the same mass. On larger scales, the distribution of compactness with main sequence mass is found to be robustly non-monotonic, implying islands of 'explodabilty,' particularly around 8-20 M {sub ?} and 25-30 M {sub ?}. The carbon-oxygen (CO) core mass of a presupernova star is a better, (though still ambiguous) discriminant of its core structure than the main sequence mass.

  16. Validation of updated neutronic calculation models proposed for Atucha-II PHWR. Part II: Benchmark comparisons of PUMA core parameters with MCNP5 and improvements due to a simple cell heterogeneity correction

    SciTech Connect (OSTI)

    Grant, C. [Comision Nacional de Energia Atomica, Av del Libertador 8250, Buenos Aires 1429 (Argentina); Mollerach, R. [Nucleoelectrica Argentina S.A., Arribenos 3619, Buenos Aires 1429 (Argentina); Leszczynski, F.; Serra, O.; Marconi, J. [Comision Nacional de Energia Atomica, Av del Libertador 8250, Buenos Aires 1429 (Argentina); Fink, J. [Nucleoelectrica Argentina S.A., Arribenos 3619, Buenos Aires 1429 (Argentina)

    2006-07-01

    In 2005 the Argentine Government took the decision to complete the construction of the Atucha-II nuclear power plant, which has been progressing slowly during the last ten years. Atucha-II is a 745 MWe nuclear station moderated and cooled with heavy water, of German (Siemens) design located in Argentina. It has a pressure vessel design with 451 vertical coolant channels and the fuel assemblies (FA) are clusters of 37 natural UO{sub 2} rods with an active length of 530 cm. For the reactor physics area, a revision and update of reactor physics calculation methods and models was recently carried out covering cell, supercell (control rod) and core calculations. This paper presents benchmark comparisons of core parameters of a slightly idealized model of the Atucha-I core obtained with the PUMA reactor code with MCNP5. The Atucha-I core was selected because it is smaller, similar from a neutronic point of view, more symmetric than Atucha-II, and has some experimental data available. To validate the new models benchmark comparisons of k-effective, channel power and axial power distributions obtained with PUMA and MCNP5 have been performed. In addition, a simple cell heterogeneity correction recently introduced in PUMA is presented, which improves significantly the agreement of calculated channel powers with MCNP5. To complete the validation, the calculation of some of the critical configurations of the Atucha-I reactor measured during the experiments performed at first criticality is also presented. (authors)

  17. What Protects the Core When the Thiolated Gold Cluster is Extremely Small?

    SciTech Connect (OSTI)

    Jiang, Deen [ORNL; Chen, Wei [University of Puerto Rico; Whetten, Robert L [Georgia Institute of Technology; Chen, Zhongfang [University of Georgia, Athens, GA

    2009-01-01

    The title question is motivated by the fact that extremely small thiolated-gold clusters such as Au{sub 20}(SR){sub 16} have been isolated, but their undetermined structures cannot be fully rationalized by the present knowledge derived from single-crystal structures of larger clusters. One needs to go beyond the linear monomer (RSAuSR) and V-shaped dimer (RSAuSRAuSR) motifs that were found to protect larger clusters. We hypothesize that the U-shaped trimer motif (RSAuSRAuSRAuSR) is required to protect the core of some extremely small thiolated-gold clusters, which have about 20 or fewer Au atoms. We test this hypothesis by proposing structural models for Au{sub 10}(SR){sub 8} based on two trimer motifs protecting a tetrahedral Au{sub 4} core and for Au{sub 20}(SR){sub 16} based on four trimer motifs protecting an Au{sub 8} core.

  18. Full Core, Heterogeneous, Time Dependent Neutron Transport Calculations with the 3D Code DeCART

    E-Print Network [OSTI]

    Hursin, Mathieu

    2010-01-01

    core layout for the 1/8th PWR core model ________________ 76and future of the NEACRP PWR core transient benchmark. 199449. Hursin, M. (2008). PWR Control Rod Ejection Analysis

  19. Thermal and compositional stratification of the inner core

    E-Print Network [OSTI]

    Labrosse, Stéphane

    2014-01-01

    The improvements on the knowledge of the seismic structure of the inner core and the complexities thereby revealed ask for a dynamical origin. Sub-solidus convection was one of the early suggestions to explain the seismic anisotropy but requires an unstable density gradient either from thermal or compositional origin, or both. Temperature and composition profiles in the inner core are computed using a unidimensional model of core evolution including diffusion in the inner core and fractional crystallization at the the inner core boundary (ICB). The thermal conductivity of the core has been recently revised upwardly and, moreover, found increasing with depth. Values of the heat flow across the core mantle boundary (CMB) sufficient to maintain convection in the whole outer core are not sufficient to make the temperature in the inner core super-isentropic and therefore prone to thermal instability. An unreasonably high CMB heat flow is necessary to this end. The compositional stratification results from a compet...

  20. Developing Renewable Energy Projects Larger Than 10 MWs at Federal Facilities

    SciTech Connect (OSTI)

    2013-03-01

    To accomplish Federal goals for renewable energy, sustainability, and energy security, large-scale renewable energy projects must be developed and constructed on Federal sites at a significant scale with significant private investment. For the purposes of this Guide, large-scale Federal renewable energy projects are defined as renewable energy facilities larger than 10 megawatts (MW) that are sited on Federal property and lands and typically financed and owned by third parties.1 The U.S. Department of Energy’s Federal Energy Management Program (FEMP) helps Federal agencies meet these goals and assists agency personnel navigate the complexities of developing such projects and attract the necessary private capital to complete them. This Guide is intended to provide a general resource that will begin to develop the Federal employee’s awareness and understanding of the project developer’s operating environment and the private sector’s awareness and understanding of the Federal environment. Because the vast majority of the investment that is required to meet the goals for large-scale renewable energy projects will come from the private sector, this Guide has been organized to match Federal processes with typical phases of commercial project development. FEMP collaborated with the National Renewable Energy Laboratory (NREL) and professional project developers on this Guide to ensure that Federal projects have key elements recognizable to private sector developers and investors. The main purpose of this Guide is to provide a project development framework to allow the Federal Government, private developers, and investors to work in a coordinated fashion on large-scale renewable energy projects. The framework includes key elements that describe a successful, financially attractive large-scale renewable energy project. This framework begins the translation between the Federal and private sector operating environments. When viewing the overall

  1. Secure Core Contact Information

    E-Print Network [OSTI]

    Secure Core Contact Information C. E. Irvine irvine@nps.edu 831-656-2461 Department of Computer for the secure management of local and/or remote information in multiple contexts. The SecureCore project Science Graduate School of Operations and Information Sciences www.cisr.nps.edu Project Description

  2. Features of the Acoustic Mechanism of Core-Collapse Supernova Explosions

    E-Print Network [OSTI]

    A. Burrows; E. Livne; L. Dessart; C. D. Ott; J. Murphy

    2006-10-05

    In the context of 2D, axisymmetric, multi-group, radiation/hydrodynamic simulations of core-collapse supernovae over the full 180$^{\\circ}$ domain, we present an exploration of the progenitor dependence of the acoustic mechanism of explosion. All progenitor models we have tested with our Newtonian code explode. We investigate the roles of the Standing-Accretion-Shock-Instability (SASI), the excitation of core g-modes, the generation of core acoustic power, the ejection of matter with r-process potential, the wind-like character of the explosion, and the fundamental anisotropy of the blasts. We find that the breaking of spherical symmetry is central to the supernova phenomenon and the blasts, when top-bottom asymmetric, are self-collimating. We see indications that the initial explosion energies are larger for the more massive progenitors, and smaller for the less massive progenitors, and that the neutrino contribution to the explosion energy may be an increasing function of progenitor mass. The degree of explosion asymmetry we obtain is completely consistent with that inferred from the polarization measurements of Type Ic supernovae. Furthermore, we calculate for the first time the magnitude and sign of the net impulse on the core due to anisotropic neutrino emission and suggest that hydrodynamic and neutrino recoils in the context of our asymmetric explosions afford a natural mechanism for observed pulsar proper motions. [abridged

  3. oftware systems are becoming larger and more complex. At the same time, they are being de-

    E-Print Network [OSTI]

    Lu, Chenyang

    control design and implementation for software systems. Middle- ware solutions such as Control of feedback control. We describe modeling the software system and pro- vide an example of performance control the computing and control sub- systems of a software application and automates many parts of the feedback

  4. 6th ACM Symposium on Solid Modeling and Applications, to appear June, 2001 Out-of-Core Build of a Topological Data Structure from Polygon Soup

    E-Print Network [OSTI]

    McMains, Sara

    not provide this information, which the ap- plication must then derive as it builds its own topological data. In this paper, we describe a new out-of-core al- gorithm that can build a topological data structure efficiently in memory, it is efficient for the application to build up its own topological data structure by in

  5. Midland Core Repository

    SciTech Connect (OSTI)

    Tyler, Noel

    2000-08-14

    This report summarizes activities for the repository during this quarter. The repository holds drill cores and cuttings samples from oil wells that can be viewed or checked out by users.

  6. Core assembly storage structure

    DOE Patents [OSTI]

    Jones, Jr., Charles E. (Northridge, CA); Brunings, Jay E. (Chatsworth, CA)

    1988-01-01

    A structure for the storage of core assemblies from a liquid metal-cooled nuclear reactor. The structure comprises an enclosed housing having a substantially flat horizontal top plate, a bottom plate and substantially vertical wall members extending therebetween. A plurality of thimble members extend downwardly through the top plate. Each thimble member is closed at its bottom end and has an open end adjacent said top plate. Each thimble member has a length and diameter greater than that of the core assembly to be stored therein. The housing is provided with an inlet duct for the admission of cooling air and an exhaust duct for the discharge of air therefrom, such that when hot core assemblies are placed in the thimbles, the heat generated will by convection cause air to flow from the inlet duct around the thimbles and out the exhaust duct maintaining the core assemblies at a safe temperature without the necessity of auxiliary powered cooling equipment.

  7. Main Sequence Evolution As the hydrogen in its core is slowly used up, a star's

    E-Print Network [OSTI]

    Barnes, Joshua Edward

    Main Sequence Evolution As the hydrogen in its core is slowly used up, a star's `thermostat photosphere hydrogen- `burning' core A Main-Sequence Star... photosphere hydrogen- `burning' shell inert the Main Sequence Once hydrogen starts burning in a shell, a star becomes larger, redder, and much more

  8. Emergency core cooling system

    DOE Patents [OSTI]

    Schenewerk, William E. (Sherman Oaks, CA); Glasgow, Lyle E. (Westlake Village, CA)

    1983-01-01

    A liquid metal cooled fast breeder reactor provided with an emergency core cooling system includes a reactor vessel which contains a reactor core comprising an array of fuel assemblies and a plurality of blanket assemblies. The reactor core is immersed in a pool of liquid metal coolant. The reactor also includes a primary coolant system comprising a pump and conduits for circulating liquid metal coolant to the reactor core and through the fuel and blanket assemblies of the core. A converging-diverging venturi nozzle with an intermediate throat section is provided in between the assemblies and the pump. The intermediate throat section of the nozzle is provided with at least one opening which is in fluid communication with the pool of liquid sodium. In normal operation, coolant flows from the pump through the nozzle to the assemblies with very little fluid flowing through the opening in the throat. However, when the pump is not running, residual heat in the core causes fluid from the pool to flow through the opening in the throat of the nozzle and outwardly through the nozzle to the assemblies, thus providing a means of removing decay heat.

  9. Large-Scale Renewable Energy Guide: Developing Renewable Energy Projects Larger Than 10 MWs at Federal Facilities

    Broader source: Energy.gov [DOE]

    The Large-Scale Renewable Energy Guide: Developing Renewable Energy Projects Larger Than 10 MWs at Federal Facilities provides best practices and other helpful guidance for federal agencies developing large-scale renewable energy projects.

  10. All-University Core Curriculum All-University Core Curriculum

    E-Print Network [OSTI]

    All-University Core Curriculum All-University Core Curriculum Office of Vice Provost-UNIVERSITY CORE CURRICULUM (AUCC) All Colorado State University students share a learning experience in common recommendations for satisfying All- University Core Curriculum requirements. A student must earn a cumulative

  11. All-University Core Curriculum All-University Core Curriculum

    E-Print Network [OSTI]

    Collett Jr., Jeffrey L.

    All-University Core Curriculum _______________ 2.3 Page 1 All-University Core Curriculum Office-UNIVERSITY CORE CURRICULUM (AUCC) All Colorado State University students share a learning experience in common if their preferred program of study has particular recommendations for satisfying All- University Core Curriculum

  12. MIGRATION AND GROWTH OF PROTOPLANETARY EMBRYOS. II. EMERGENCE OF PROTO-GAS-GIANT CORES VERSUS SUPER EARTH PROGENITORS

    SciTech Connect (OSTI)

    Liu, Beibei; Zhang, Xiaojia; Lin, Douglas N. C.; Aarseth, Sverre J.

    2015-01-01

    Nearly 15%-20% of solar type stars contain one or more gas giant planets. According to the core-accretion scenario, the acquisition of their gaseous envelope must be preceded by the formation of super-critical cores with masses 10 times or larger than that of the Earth. It is natural to link the formation probability of gas giant planets with the supply of gases and solids in their natal disks. However, a much richer population of super Earths suggests that (1) there is no shortage of planetary building block material, (2) a gas giant's growth barrier is probably associated with whether it can merge into super-critical cores, and (3) super Earths are probably failed cores that did not attain sufficient mass to initiate efficient accretion of gas before it is severely depleted. Here we construct a model based on the hypothesis that protoplanetary embryos migrated extensively before they were assembled into bona fide planets. We construct a Hermite-Embryo code based on a unified viscous-irradiation disk model and a prescription for the embryo-disk tidal interaction. This code is used to simulate the convergent migration of embryos, and their close encounters and coagulation. Around the progenitors of solar-type stars, the progenitor super-critical-mass cores of gas giant planets primarily form in protostellar disks with relatively high (? 10{sup –7} M {sub ?} yr{sup –1}) mass accretion rates, whereas systems of super Earths (failed cores) are more likely to emerge out of natal disks with modest mass accretion rates, due to the mean motion resonance barrier and retention efficiency.

  13. Features of the application of the Monte Carlo method to calculations for large RBMK reactors and to model correction on the basis of data from in-core detectors

    SciTech Connect (OSTI)

    Ivanov, I. E., E-mail: ilshai-hulud@yandex.ru; Schukin, N. V. [National Research Nuclear University MEPhI (Russian Federation); Bychkov, S. A.; Druzhinin, V. E.; Lysov, D. A.; Shmonin, Yu. V. [All-Russia Research Institute for Nuclear Power Plant Operation (VNIIAES) (Russian Federation); Gurevich, M. I. [National Research Center Kurchatov Institute (Russian Federation)

    2014-12-15

    Statistical errors in sampling neutron fields in physically large systems like an RBMK are analyzed both qualitatively and quantitatively. Recommendations concerning the choice of parameters for calculations are given. A new procedure for Monte Carlo RBMK calculations with model corrections on the basis of data from in-core detectors is proposed. Dedicated software based on the CUDA software and hardware platform is developed for computational research. Results of testing the procedure and software in question via calculations for real RBMK reactors are discussed.

  14. Strategic Plan Core strategies

    E-Print Network [OSTI]

    Oxford, University of

    Strategic Plan 2013­18 Vision Priorities Core strategies Enabling strategies #12;Strategic Plan on the Strategic Plan, ensuring that it continues to meet academic needs, enables us to respond to the external the framework for making the Strategic Plan operational at divisional and service level. ©UniversityofOxford #12

  15. A Parameter Study of Type II Supernova Light Curves Using 6 M_odot He Cores

    E-Print Network [OSTI]

    Timothy R. Young

    2004-09-13

    Results of numerical calculations of Type II supernova light curves are presented. The model progenitor stars have 6 $M{_\\odot}$ cores and various envelopes, originating from a numerically evolved 20 $M{_\\odot}$ star. Five parameters that affect the light curves are examined: the ejected mass, the progenitor radius, the explosion energy, the $^{56}$Ni mass, and the extent of $^{56}$Ni mixing. The following affects have been found: 1) the larger the progenitor radius the brighter the early--time light curve, with little affect on the late--time light curve, 2) the larger the envelope mass the fainter the early light curve and the flatter the slope of the late light curve, 3) the larger the explosion energy the brighter the early light curve and the steeper the slope of the late light curve, 4) the larger the $^{56}$Ni mass the brighter the overall light curve after 20 to 50 days, with no affect on the early light curve, 5) the more extensive the $^{56}$Ni mixing the brighter the early light curve and the steeper the late light curve. The primary parameters affecting the light curve shape are the progenitor radius and the ejected mass. The secondary parameters are the explosion energy, $^{56}$Ni mass and $^{56}$Ni mixing. I find that while in principle the general shape and absolute magnitude of a light curve indicate a unique set of parameters, in practice it is difficult to avoid some ambiguity in the parameters. I find that the nickel--powered diffusion wave and the recombination of helium produce a prominent secondary peak in all our calculations. The feature is less prominent when compositional mixing, both $^{56}$Ni mixing and mixing between the hydrogen and helium layers, occurs. The model photospheric temperatures and velocities are presented, for comparison to observation.

  16. Abstract--As information networks grow larger in size due to automation or organizational integration, it is important to

    E-Print Network [OSTI]

    Gautam, Natarajan

    on networked systems in many domains due to automation or organizational integration. The growth in complexity element and component technology utilizes the components so that developers can build systems needed1 Abstract--As information networks grow larger in size due to automation or organizational

  17. Illusionist: Transforming Lightweight Cores into Aggressive Cores on Demand

    E-Print Network [OSTI]

    Torrellas, Josep

    Illusionist: Transforming Lightweight Cores into Aggressive Cores on Demand HPCA-19 February 27;Adapting to Application Demands Number of threads to execute is not constant o Many threads available

  18. Cluster Cores, Gravitational Lensing, and Cosmology

    E-Print Network [OSTI]

    Ricardo A. Flores; Joel R. Primack

    1995-12-11

    Many multiply--imaged quasars have been found over the years, but none so far with image separation in excess of $8\\arcsec$. The absence of such large splittings has been used as a test of cosmological models: the standard Cold Dark Matter model has been excluded on the basis that it predicts far too many large--separation double images. These studies assume that the lensing structure has the mass profile of a singular isothermal sphere. However, such large splittings would be produced by very massive systems such as clusters of galaxies, for which other gravitational lensing data suggest less singular mass profiles. Here we analyze two cases of mass profiles for lenses: an isothermal sphere with a finite core radius (density $\\rho \\propto (r^2+r_{core}^2)^{-1})$, and a Hernquist profile ($\\rho \\propto r^{-1}(r+a)^{-3}$). We find that small core radii $r_{core} \\sim 30 h^{-1}$ kpc, as suggested by the cluster data, or large $a \\gsim 300 h^{-1}$ kpc, as needed for compatibility with gravitational distortion data, would reduce the number of large--angle splittings by an order of magnitude or more. Thus, it appears that these tests are sensitive both to the cosmological model (number density of lenses) and to the inner lens structure, which is unlikely to depend sensitively on the cosmology, making it difficult to test the cosmological models by large--separation quasar lensing until we reliably know the structure of the lenses themselves.

  19. Origin of the Core Francis Nimmo

    E-Print Network [OSTI]

    Nimmo, Francis

    system, including the Earth, are composed primarily of iron and silicates. Due to its high density. Simple models of solar system formation suggest that 2 #12;elements with relatively low condensationOrigin of the Core Francis Nimmo Dept. Earth Sciences, University of California, Santa Cruz F

  20. Electromagnetic pump stator core

    DOE Patents [OSTI]

    Fanning, A.W.; Olich, E.E.; Dahl, L.R.

    1995-01-17

    A stator core for supporting an electrical coil includes a plurality of groups of circumferentially abutting flat laminations which collectively form a bore and perimeter. A plurality of wedges are interposed between the groups, with each wedge having an inner edge and a thicker outer edge. The wedge outer edges abut adjacent ones of the groups to provide a continuous path around the perimeter. 21 figures.

  1. Banded electromagnetic stator core

    DOE Patents [OSTI]

    Fanning, A.W.; Gonzales, A.A.; Patel, M.R.; Olich, E.E.

    1994-04-05

    A stator core for an electromagnetic pump includes a plurality of circumferentially adjoining groups of flat laminations disposed about a common centerline axis and collectively defining a central bore and a discontinuous outer perimeter, with adjacent groups diverging radially outwardly to form V-shaped gaps. An annular band surrounds the groups and is predeterminedly tensioned to clamp together the laminations, and has a predetermined flexibility in a radial direction to form substantially straight bridge sections between the adjacent groups. 5 figures.

  2. Banded electromagnetic stator core

    DOE Patents [OSTI]

    Fanning, Alan W. (San Jose, CA); Gonzales, Aaron A. (San Jose, CA); Patel, Mahadeo R. (San Jose, CA); Olich, Eugene E. (Aptos, CA)

    1994-01-01

    A stator core for an electromagnetic pump includes a plurality of circumferentially adjoining groups of flat laminations disposed about a common centerline axis and collectively defining a central bore and a discontinuous outer perimeter, with adjacent groups diverging radially outwardly to form V-shaped gaps. An annular band surrounds the groups and is predeterminedly tensioned to clamp together the laminations, and has a predetermined flexibility in a radial direction to form substantially straight bridge sections between the adjacent groups.

  3. Banded electromagnetic stator core

    DOE Patents [OSTI]

    Fanning, Alan W. (San Jose, CA); Gonzales, Aaron A. (San Jose, CA); Patel, Mahadeo R. (San Jose, CA); Olich, Eugene E. (Aptos, CA)

    1996-01-01

    A stator core for an electromagnetic pump includes a plurality of circumferentially adjoining groups of flat laminations disposed about a common centerline axis and collectively defining a central bore and a discontinuous outer perimeter, with adjacent groups diverging radially outwardly to form V-shaped gaps. An annular band surrounds the groups and is predeterminedly tensioned to clamp together the laminations, and has a predetermined flexibility in a radial direction to form substantially straight bridge sections between the adjacent groups.

  4. Variable depth core sampler

    DOE Patents [OSTI]

    Bourgeois, P.M.; Reger, R.J.

    1996-02-20

    A variable depth core sampler apparatus is described comprising a first circular hole saw member, having longitudinal sections that collapses to form a point and capture a sample, and a second circular hole saw member residing inside said first hole saw member to support the longitudinal sections of said first hole saw member and prevent them from collapsing to form a point. The second hole saw member may be raised and lowered inside said first hole saw member. 7 figs.

  5. Variable depth core sampler

    DOE Patents [OSTI]

    Bourgeois, Peter M. (Hamburg, NY); Reger, Robert J. (Grand Island, NY)

    1996-01-01

    A variable depth core sampler apparatus comprising a first circular hole saw member, having longitudinal sections that collapses to form a point and capture a sample, and a second circular hole saw member residing inside said first hole saw member to support the longitudinal sections of said first hole saw member and prevent them from collapsing to form a point. The second hole saw member may be raised and lowered inside said first hole saw member.

  6. Large Flow Birefringence of Nematogenic Bent-Core Liquid Crystals

    SciTech Connect (OSTI)

    Bailey, C.; Fodor-Csorba, K; Verduzco, R; Gleeson, J; Sprunt, S; Jakli, A

    2009-01-01

    We have found that bent-core liquid crystalline materials show exceptionally large intrinsic flow birefringence in their isotropic liquid phase. This effect is more than 100 times larger than typical values measured for low molecular weight liquid crystals. The specific flow birefringence (i.e., normalized by the flow viscosity) is an order of magnitude larger than in both side-chain polymeric as well as low molecular weight liquid crystals. We propose that this large enhancement for bent-core compounds may be attributed to nanoscale smecticlike clusters that persist above the nematic-isotropic transition temperature, and shear align under shear flow; however, this mechanism has not yet been definitively confirmed.

  7. INTRODUCTION TO THE CORE CURRICULUM

    E-Print Network [OSTI]

    Schrag, Daniel

    1 INTRODUCTION TO THE CORE CURRICULUM The purpose of this guide is to inform members of the Freshman class about Harvard's Core Curriculum. It explains the aims and design of the program, offers some of concentration. I The Core Curriculum for undergraduate education at Harvard is both a requirement

  8. 866 IEEE TRANSACTIONS ON MAGNETICS, VOL. 44, NO. 6, JUNE 2008 Dynamical Models for Eddy Current in Ferromagnetic Cores Introduced in

    E-Print Network [OSTI]

    Boyer, Edmond

    866 IEEE TRANSACTIONS ON MAGNETICS, VOL. 44, NO. 6, JUNE 2008 Dynamical Models for Eddy Current accurate dynamical models for representing eddy currents are studied. The simulation of the relay is provided. Index Terms--AC circuit breakers (CBs), eddy currents, magnetic hysteresis, optimization methods

  9. Molecular simulation study of polar order in orthogonal bent core smectic liquid crystals

    E-Print Network [OSTI]

    Stavros D. Peroukidis; Alexandros G. Vanakaras; Demetri J. Photinos

    2015-04-16

    We explore the phase behavior and structure of orthogonal smectic liquid crystals consisting of bent-core molecules (BCMs) by means of Monte Carlo molecular simulations. A simple athermal molecular model is introduced that describes the basic features of the BCMs. Phase transitions between uniaxial and biaxial (antiferroelectric) orthogonal smectics are obtained. The results indicate the presence of local in-plane polar correlations in the uniaxial smectic phase. The macroscopic uniaxial-biaxial transformation is rationalized in terms of local polar correlations giving rise to polar domains. The size of these polar domains grows larger under the action of an external vector field and their internal ordering is enhanced, leading to field-induced biaxial order-disorder transitions.

  10. Convective cores in galactic cooling flows

    E-Print Network [OSTI]

    A. Kritsuk; T. Plewa; E. Mueller

    2001-05-02

    We use hydrodynamic simulations with adaptive grid refinement to study the dependence of hot gas flows in X-ray luminous giant elliptical galaxies on the efficiency of heat supply to the gas. We consider a number of potential heating mechanisms including Type Ia supernovae and sporadic nuclear activity of a central supermassive black hole. As a starting point for this research we use an equilibrium hydrostatic recycling model (Kritsuk 1996). We show that a compact cooling inflow develops, if the heating is slightly insufficient to counterbalance radiative cooling of the hot gas in the central few kiloparsecs. An excessive heating in the centre, instead, drives a convectively unstable outflow. We model the onset of the instability and a quasi-steady convective regime in the core of the galaxy in two-dimensions assuming axial symmetry. Provided the power of net energy supply in the core is not too high, the convection remains subsonic. The convective pattern is dominated by buoyancy driven large-scale mushroom-like structures. Unlike in the case of a cooling inflow, the X-ray surface brightness of an (on average) isentropic convective core does not display a sharp maximum at the centre. A hybrid model, which combines a subsonic peripheral cooling inflow with an inner convective core, appears to be stable. We also discuss observational implications of these results.

  11. ORIGIN OF THE DENSE CORE MASS FUNCTION IN CONTRACTING FILAMENTS

    SciTech Connect (OSTI)

    Myers, Philip C.

    2013-02-20

    Mass functions of starless dense cores (CMFs) may arise from contraction and dispersal of core-forming filaments. In an illustrative model, a filament contracts radially by self-gravity, increasing the mass of its cores. During this contraction, FUV photoevaporation and ablation by shocks and winds disperse filament gas and limit core growth. The stopping times of core growth are described by a waiting-time distribution. The initial filament column density profile and the resulting CMF each match recent Herschel observations in detail. Then low-mass cores have short growth ages and arise from the innermost filament gas, while massive cores have long growth ages and draw from more extended filament gas. The model fits the initial density profile and CMF best for mean core density 2 Multiplication-Sign 10{sup 4} cm{sup -3} and filament dispersal timescale 0.5 Myr. Then the typical core mass, radius, mean column density, and contraction speed are respectively 0.8 solar masses, 0.06 pc, 6 Multiplication-Sign 10{sup 21} cm{sup -2}, and 0.07 km s{sup -1}, also in accord with observed values.

  12. Core-Collapse Supernovae

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room News PublicationsAuditsClusterInformationContract Managementthermoelectric powerTheCore

  13. ARM - Ice Cores

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Comments? WeDatastreamstps DocumentationAtlanticENAField ParticipantsField Campaign StatisticsPastIce Cores

  14. RESULTS FROM THE (1) DATA COLLECTION WORKSHOP, (2) MODELING WORKSHOP AND (3) DRILLING AND CORING METHODS WORKSHOP AS PART OF THE JOINT INDUSTRY PARTICIPATION (JIP) PROJECT TO CHARACTERIZE NATURAL GAS HYDRATES IN THE DEEPWATER GULF OF MEXICO

    SciTech Connect (OSTI)

    Stephen A. Holditch; Emrys Jones

    2002-09-01

    In 2000, Chevron began a project to learn how to characterize the natural gas hydrate deposits in the deepwater portions of the Gulf of Mexico. A Joint Industry Participation (JIP) group was formed in 2001, and a project partially funded by the U.S. Department of Energy (DOE) began in October 2001. The primary objective of this project is to develop technology and data to assist in the characterization of naturally occurring gas hydrates in the deepwater Gulf of Mexico. These naturally occurring gas hydrates can cause problems relating to drilling and production of oil and gas, as well as building and operating pipelines. Other objectives of this project are to better understand how natural gas hydrates can affect seafloor stability, to gather data that can be used to study climate change, and to determine how the results of this project can be used to assess if and how gas hydrates act as a trapping mechanism for shallow oil or gas reservoirs. As part of the project, three workshops were held. The first was a data collection workshop, held in Houston during March 14-15, 2002. The purpose of this workshop was to find out what data exist on gas hydrates and to begin making that data available to the JIP. The second and third workshop, on Geoscience and Reservoir Modeling, and Drilling and Coring Methods, respectively, were held simultaneously in Houston during May 9-10, 2002. The Modeling Workshop was conducted to find out what data the various engineers, scientists and geoscientists want the JIP to collect in both the field and the laboratory. The Drilling and Coring workshop was to begin making plans on how we can collect the data required by the project's principal investigators.

  15. Unit  045 - Non-Spatial Database Models

    E-Print Network [OSTI]

    045, CC in GIScience; Meyer, Thomas H.

    2000-01-01

    25 Unit 045 - Non-Spatial Database Models Core Curriculum -26 Unit 045 - Non-Spatial Database Models Core Curriculum -27 Unit 045 - Non-Spatial Database Models Core Curriculum -

  16. Unit 11 - Spatial Objects and Database Models

    E-Print Network [OSTI]

    Unit 11, CC in GIS; Nyerges, Timothy L.

    1990-01-01

    Spatial Objects and Database Models NCGIA Core Curriculum inSpatial Objects and Database Models NCGIA Core Curriculum inSpatial Objects and Database Models NCGIA Core Curriculum in

  17. Combined Ethanol Injection Therapy and Radiofrequency Ablation Therapy in Percutaneous Treatment of Hepatocellular Carcinoma Larger than 4 cm

    SciTech Connect (OSTI)

    Vallone, Paolo; Catalano, Orlando [National Cancer Institute, Department of Radiology (Italy)], E-mail: orlandcat@tin.it; Izzo, Francesco [National Cancer Institute, Department of Surgical Oncology 'D' (Italy); Siani, Alfredo [National Cancer Institute, Department of Radiology (Italy)

    2006-08-15

    Background. Optimal treatment of large-sized hepatocellular carcinoma (HCC) is still debated, because percutaneous ablation therapies alone do not always achieve complete necrosis. Objective. To report our experience in the treatment of patients with HCC larger than 4 cm in diameter by combined percutaneous ethanol injection and radiofrequency thermal ablation. Methods. In a 5-year period there were 40 consecutive patients meeting the inclusion criteria (24 men and 16 women; age range 41-72 years, mean 58 years). These subjects had a single HCC larger than 4 cm. Twelve subjects also had one or two additional nodules smaller than 4 cm (mean 1.2 nodules per patient). Patients were submitted to one to three sessions consisting of ethanol injection at two opposite tumor poles (mean 12 ml) and then of radiofrequency application through one or two electrodes placed at the tumor center (mean treatment duration 30 min). Results. Complete necrosis was obtained in all cases with one to three sessions (mean 1.3 sessions per patient). All patients experienced pain and fever but one only subject had a major complication requiring treatment (abscess development and fistulization). Overall follow-up was 7-69 months. Two patients showed local recurrence and 9 developed new etherotopic HCC nodules. Seven subjects died during follow-up while 33 were free from recurrence 8-69 months after treatment. Conclusion. A combination of ethanol injection and radiofrequency ablation is effective in the treatment of large HCC.

  18. THE BRIGHTEST CLUSTER GALAXY IN A85: THE LARGEST CORE KNOWN SO FAR

    SciTech Connect (OSTI)

    López-Cruz, O.; Añorve, C.; Ibarra-Medel, H. J.; Birkinshaw, M.; Worrall, D. M.; Barkhouse, W. A.; Torres-Papaqui, J. P.

    2014-11-10

    We have found that the brightest cluster galaxy (BCG) in A85, Holm 15A, displays the largest core known so far. Its cusp radius, r {sub ?} = 4.57 ± 0.06 kpc (4.''26 ± 0.''06), is more than 18 times larger than the mean for BCGs and ? 1 kpc larger than A2261-BCG, hitherto the largest-cored BCG. Holm 15A hosts the luminous amorphous radio source 0039-095B and has the optical signature of a LINER. Scaling laws indicate that this core could host a supermassive black hole (SMBH) of mass M {sub •} ? (10{sup 9}-10{sup 11}) M {sub ?}. We suggest that cores this large represent a relatively short phase in the evolution of BCGs, whereas the masses of their associated SBMH might be set by initial conditions.

  19. Complex Modulus Prediction of Asphalt Concrete Pavement Cores 

    E-Print Network [OSTI]

    Ling, Meng

    2013-12-02

    . For field cores complex modulus measuring methods, except some expensive pavement field testers, empirical and semiempirical models are widely used, but an accurate mechanical test method is more desired. In this research, Arizona, Yellowstone National Park...

  20. The dynamic indentation response of sandwich panels with a corrugated or Y-frame core

    E-Print Network [OSTI]

    St-Pierre, L.; Fleck, N. A.; Deshpande, V. S.

    2014-12-30

    of such accidents has the potential to increase in the future as maritime traffic increases and as vessels become larger and faster. Thus, it is vital that ship structures have adequate strength and energy absorption capacity to resist collisions... (and their resistance to security threats such as air blast) can be improved by the appropriate choice of an energy absorbing core in a sandwich configuration. This motivates the present basic study: we explore the resistance of sandwich cores...

  1. Generating unstructured nuclear reactor core meshes in parallel

    SciTech Connect (OSTI)

    Jain, Rajeev; Tautges, Timothy J.

    2014-10-24

    Recent advances in supercomputers and parallel solver techniques have enabled users to run large simulations problems using millions of processors. Techniques for multiphysics nuclear reactor core simulations are under active development in several countries. Most of these techniques require large unstructured meshes that can be hard to generate in a standalone desktop computers because of high memory requirements, limited processing power, and other complexities. We have previously reported on a hierarchical lattice-based approach for generating reactor core meshes. Here, we describe efforts to exploit coarse-grained parallelism during reactor assembly and reactor core mesh generation processes. We highlight several reactor core examples including a very high temperature reactor, a full-core model of the Korean MONJU reactor, a ¼ pressurized water reactor core, the fast reactor Experimental Breeder Reactor-II core with a XX09 assembly, and an advanced breeder test reactor core. The times required to generate large mesh models, along with speedups obtained from running these problems in parallel, are reported. A graphical user interface to the tools described here has also been developed.

  2. Isolated starless cores in IRDCs in the Hi-GAL survey

    E-Print Network [OSTI]

    Wilcock, L A; Kirk, J M; Stamatellos, D; Whitworth, A; Battersby, C; Elia, D; Fuller, G A; DiGiorgio, A; Griffin, M J; Molinari, S; Martin, P; Mottram, J C; Peretto, N; Pestalozzi, M; Schisano, E; Smith, H A; Thompson, M A

    2012-01-01

    In a previous paper we identified cores within infrared dark clouds (IRDCs). We regarded those without embedded sources as the least evolved, and labelled them starless. Here we identify the most isolated starless cores and model them using a three-dimensional, multi-wavelength, Monte Carlo, radiative transfer code. We derive the cores' physical parameters and discuss the relation between the mass, temperature, density, size and the surrounding interstellar radiation field (ISRF) for the cores. The masses of the cores were found not to correlate with their radial size or central density. The temperature at the surface of a core was seen to depend almost entirely on the level of the ISRF surrounding the core. No correlation was found between the temperature at the centre of a core and its local ISRF. This was seen to depend, instead, on the density and mass of the core.

  3. The Dark Matter Radial Profile in the Core of the Relaxed Cluster A2589

    E-Print Network [OSTI]

    David A. Buote; Aaron D. Lewis

    2004-01-29

    We present an analysis of a Chandra--ACIS observation of the galaxy cluster A2589 to constrain the radial distribution of the total gravitating matter and the dark matter in the core of the cluster. A2589 is especially well-suited for this analysis because the hot gas in its core region (r < ~0.1 Rvir) is undisturbed by interactions with a central radio source. From the largest radius probed (r=0.07 Rvir) down to r ~0.02 Rvir dark matter dominates the gravitating mass. Over this region the radial profiles of the gravitating and dark matter are fitted well by the NFW and Hernquist profiles predicted by CDM. The density profiles are also described well by power laws, rho ~r^{-alpha}, where alpha=1.37 +/- 0.14 for the gravitating matter and alpha=1.35 +/- 0.21 for the dark matter. These values are consistent with profiles of CDM halos but are significantly larger than alpha ~0.5 found in LSB galaxies and expected from self-interacting dark matter models.

  4. Stellar convective cores as dark matter probes

    E-Print Network [OSTI]

    Jordi Casanellas; Isa M. Brandão; Yveline Lebreton

    2015-05-06

    The recent detection of a convective core in a main-sequence solar-type star is used here to test particular models of dark matter (DM) particles, those with masses and scattering cross sections in the range of interest for the DM interpretation of the positive results in several DM direct detection experiments. If DM particles do not effectively self-annihilate after accumulating inside low-mass stars (e.g. in the asymmetric DM scenario) their conduction provides an efficient mechanism of energy transport in the stellar core. For main-sequence stars with masses between 1.1 and 1.3 Msun, this mechanism may lead to the suppression of the inner convective region expected to be present in standard stellar evolution theory. The asteroseismic analysis of the acoustic oscillations of a star can prove the presence/absence of such a convective core, as it was demonstrated for the first time with the Kepler field main-sequence solar-like pulsator, KIC 2009505. Studying this star we found that the asymmetric DM interpretation of the results in the CoGeNT experiment is incompatible with the confirmed presence of a small convective core in KIC 2009505.

  5. Probing Pre-Protosellar Cores with Formaldehyde

    E-Print Network [OSTI]

    Kaisa E. Young; Jeong-Eun Lee; Neal J. Evans II; Paul F. Goldsmith; Steven D. Doty

    2004-06-23

    We present maps of the 6 cm and 1.3 mm transitions of formaldehyde toward three cold, dense pre-protostellar cores: L1498, L1512, and L1544. The 6 cm transition is a unique probe of high density gas at low temperature. However, our models unequivocally indicate that H2CO is depleted in the interiors of PPCs, and depletion significantly affects how H2CO probes the earliest stages of star formation. Multi-stage, self-consistent models, including gas--dust energetics, of both H2CO transitions are presented, and the implications of the results are discussed.

  6. Generating unstructured nuclear reactor core meshes in parallel

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

    Jain, Rajeev; Tautges, Timothy J.

    2014-10-24

    Recent advances in supercomputers and parallel solver techniques have enabled users to run large simulations problems using millions of processors. Techniques for multiphysics nuclear reactor core simulations are under active development in several countries. Most of these techniques require large unstructured meshes that can be hard to generate in a standalone desktop computers because of high memory requirements, limited processing power, and other complexities. We have previously reported on a hierarchical lattice-based approach for generating reactor core meshes. Here, we describe efforts to exploit coarse-grained parallelism during reactor assembly and reactor core mesh generation processes. We highlight several reactor coremore »examples including a very high temperature reactor, a full-core model of the Korean MONJU reactor, a ¼ pressurized water reactor core, the fast reactor Experimental Breeder Reactor-II core with a XX09 assembly, and an advanced breeder test reactor core. The times required to generate large mesh models, along with speedups obtained from running these problems in parallel, are reported. A graphical user interface to the tools described here has also been developed.« less

  7. Ice chemistry in starless molecular cores

    E-Print Network [OSTI]

    Kalvans, Juris

    2015-01-01

    Starless molecular cores are natural laboratories for interstellar molecular chemistry research. The chemistry of ices in such objects was investigated with a three-phase (gas, surface, and mantle) model. We considered the center part of five starless cores, with their physical conditions derived from observations. The ice chemistry of oxygen, nitrogen, sulfur, and complex organic molecules (COMs) was analyzed. We found that an ice-depth dimension, measured, e.g., in monolayers, is essential for modeling of chemistry in interstellar ices. Particularly, the H2O:CO:CO2:N2:NH3 ice abundance ratio regulates the production and destruction of minor species. It is suggested that photodesorption during core collapse period is responsible for high abundance of interstellar H2O2 and O2H, and other species synthesized on the surface. The calculated abundances of COMs in ice were compared to observed gas-phase values. Smaller activation barriers for CO and H2CO hydrogenation may help explain the production of a number of...

  8. Earth's Inner Core dynamics induced by the Lorentz force

    E-Print Network [OSTI]

    Lasbleis, M; Cardin, P; Labrosse, S

    2015-01-01

    Seismic studies indicate that the Earth's inner core has a complex structure and exhibits a strong elastic anisotropy with a cylindrical symmetry. Among the various models which have been proposed to explain this anisotropy, one class of models considers the effect of the Lorentz force associated with the magnetic field diffused within the inner core. In this paper we extend previous studies and use analytical calculations and numerical simulations to predict the geometry and strength of the flow induced by the poloidal component of the Lorentz force in a neutrally or stably stratified growing inner core, exploring also the effect of different types of boundary conditions at the inner core boundary (ICB). Unlike previous studies, we show that the boundary condition that is most likely to produce a significant deformation and seismic anisotropy is impermeable, with negligible radial flow through the boundary. Exact analytical solutions are found in the case of a negligible effect of buoyancy forces in the inne...

  9. The AGB bump: a calibrator for the core mixing

    E-Print Network [OSTI]

    Bossini, Diego; Salaris, Maurizio; Girardi, Léo; Montalbán, Josefina; Bressan, Alessandro; Marigo, Paola; Noels, Arlette

    2015-01-01

    The efficiency of convection in stars affects many aspects of their evolution and remains one of the key-open questions in stellar modelling. In particular, the size of the mixed core in core-He-burning low-mass stars is still uncertain and impacts the lifetime of this evolutionary phase and, e.g., the C/O profile in white dwarfs. One of the known observables related to the Horizontal Branch (HB) and Asymptotic Giant Branch (AGB) evolution is the AGB bump. Its luminosity depends on the position in mass of the helium-burning shell at its first ignition, that is affected by the extension of the central mixed region. In this preliminary work we show how various assumptions on near-core mixing and on the thermal stratification in the overshooting region affect the luminosity of the AGB bump, as well as the period spacing of gravity modes in core-He-burning models.

  10. IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING, VOL. 55, NO. 5, MAY 2008 1477 Individualized Short-Term Core Temperature

    E-Print Network [OSTI]

    for real-time con- tinuous monitoring and prediction of body core temperature would be highly desirable-Term Core Temperature Prediction in Humans Using Biomathematical Models Andrei V. Gribok, Mark J. Buller modeling techniques to predict individual- specific body core temperature variations during physical

  11. Modeling particle deposition on HVAC heat exchangers

    SciTech Connect (OSTI)

    Siegel, J.A.; Nazaroff, W.W.

    2002-01-01

    Fouling of fin-and-tube heat exchangers by particle deposition leads to diminished effectiveness in supplying ventilation and air conditioning. This paper explores mechanisms that cause particle deposition on heat exchanger surfaces. We present a model that accounts for impaction, diffusion, gravitational settling, and turbulence. Simulation results suggest that some submicron particles deposit in the heat exchanger core, but do not cause significant performance impacts. Particles between 1 and 10 {micro}m deposit with probabilities ranging from 1-20% with fin edge impaction representing the dominant mechanism. Particles larger than 10 {micro}m deposit by impaction on refrigerant tubes, gravitational settling on fin corrugations, and mechanisms associated with turbulent airflow. The model results agree reasonably well with experimental data, but the deposition of larger particles at high velocities is underpredicted. Geometric factors, such as discontinuities in the fins, are hypothesized to be responsible for the discrepancy.

  12. Vice President of Core Facilities

    E-Print Network [OSTI]

    MacAdam, Keith

    ) Research Integrity Federal Relations Sponsored Projects Administration, AVPR Advanced Science & Technology Veterinarian Research Communications Centers & Institutes · Center for Applied Energy Research (CAER) · CenterVice President of Research Core Facilities · Clinical Research Development and Operations Center

  13. Holistic design for multi-core architectures

    E-Print Network [OSTI]

    Kumar, Rakesh

    2006-01-01

    Design for Adaptability: Power Advantages of A. Discussion of Core Switching . . . . . . . . . . . .power dissipation and expected performance. This simpli?es the design of core- switching

  14. Computed microtomography of reservoir core samples

    SciTech Connect (OSTI)

    Coles, M.E.; Muegge, E.L.; Spanne, P.; Jones, K.W.

    1995-03-01

    X-ray computed tomography (CT) is often utilized to evaluate and characterize structural characteristics within reservoir core material systems. Generally, medical CT scanners have been employed because of their availability and ease of use. Of interest lately has been the acquisition of three-dimensional, high resolution descriptions of rock and pore structures for characterization of the porous media and for modeling of single and multiphase transport processes. The spatial resolution of current medical CT scanners is too coarse for pore level imaging of most core samples. Recently developed high resolution computed microtomography (CMT) using synchrotron X-ray sources is analogous to conventional medical CT scanning and provides the ability to obtain three-dimensional images of specimens with a spatial resolution on the order of micrometers. Application of this technique to the study of core samples provides two- and three-dimensional high resolution description of pore structure and mineral distributions. Pore space and interconnectivity is accurately characterized and visualized. Computed microtomography data can serve as input into pore-level simulation techniques. A generalized explanation of the technique is provided, with comparison to conventional CT scanning techniques and results. Computed microtomographic results of several sandstone samples are presented and discussed. Bulk porosity values and mineralogical identification were obtained from the microtomograms and compared with gas porosity and scanning electron microscope results on tandem samples.

  15. Essential Ingredients in Core-collapse Supernovae

    SciTech Connect (OSTI)

    Hix, William Raphael [ORNL; Lentz, E. J. [University of Tennessee (UTK) and Oak Ridge National Laboratory (ORNL); Endeve, Eirik [ORNL; Baird, Mark L [ORNL; Chertkow, Merek A [ORNL; Harris, James A [ORNL; Messer, Bronson [ORNL; Mezzacappa, Anthony [ORNL; Bruenn, S. W. [Florida Atlantic University, Boca Raton; Blondin, J. M. [North Carolina State University

    2014-01-01

    Marking the inevitable death of a massive star, and the birth of a neutron star or black hole, core-collapse supernovae bring together physics at a wide range in spatial scales, from kilometer-sized hydrodynamic motions (eventually growing to gigameter scale) down to femtometer scale nuclear reactions. Carrying 10$^{44}$ joules of kinetic energy and a rich-mix of newly synthesized atomic nuclei, core-collapse supernovae are the preeminent foundries of the nuclear species which make up ourselves and our solar system. We will discuss our emerging understanding of the convectively unstable, neutrino-driven explosion mechanism, based on increasingly realistic neutrino-radiation hydrodynamic simulations that include progressively better nuclear and particle physics. Recent multi-dimensional models with spectral neutrino transport from several research groups, which slowly develop successful explosions for a range of progenitors, have motivated changes in our understanding of the neutrino reheating mechanism. In a similar fashion, improvements in nuclear physics, most notably explorations of weak interactions on nuclei and the nuclear equation of state, continue to refine our understanding of how supernovae explode. Recent progress on both the macroscopic and microscopic effects that affect core-collapse supernovae are discussed.

  16. Essential ingredients in core-collapse supernovae

    SciTech Connect (OSTI)

    Hix, W. Raphael [Physics Division, Oak Ridge National Laboratory, Oak Ridge TN 37831-6354 (United States) [Physics Division, Oak Ridge National Laboratory, Oak Ridge TN 37831-6354 (United States); Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996-1200 (United States); Lentz, Eric J.; Chertkow, M. Austin; Harris, J. Austin [Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996-1200 (United States)] [Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996-1200 (United States); Endeve, Eirik [Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge TN 37831-6008 (United States)] [Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge TN 37831-6008 (United States); Baird, Mark [Reactor and Nuclear Systems Division, Oak Ridge National Laboratory, Oak Ridge TN 37831-6003 (United States)] [Reactor and Nuclear Systems Division, Oak Ridge National Laboratory, Oak Ridge TN 37831-6003 (United States); Messer, O. E. Bronson [Physics Division, Oak Ridge National Laboratory, Oak Ridge TN 37831-6354 (United States) [Physics Division, Oak Ridge National Laboratory, Oak Ridge TN 37831-6354 (United States); Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996-1200 (United States); Center for Computational Sciences, Oak Ridge National Laboratory, Oak Ridge TN 37831-6008 (United States); Mezzacappa, Anthony [Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996-1200 (United States) [Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996-1200 (United States); Joint Institute for Computational Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6173 (United States); Bruenn, Stephen [Department of Physics, Florida Atlantic University, 777 W Glades Road, Boca Raton, FL 33431-0991 (United States)] [Department of Physics, Florida Atlantic University, 777 W Glades Road, Boca Raton, FL 33431-0991 (United States); Blondin, John [Department of Physics, North Carolina State University, Raleigh, NC 27695-8202 (United States)] [Department of Physics, North Carolina State University, Raleigh, NC 27695-8202 (United States)

    2014-04-15

    Carrying 10{sup 44} joules of kinetic energy and a rich mix of newly synthesized atomic nuclei, core-collapse supernovae are the preeminent foundries of the nuclear species which make up our solar system and ourselves. Signaling the inevitable death of a massive star, and the birth of a neutron star or black hole, core-collapse supernovae combine physics over a wide range in spatial scales, from kilometer-sized hydrodynamic motions (eventually growing to gigameter scale) down to femtometer-scale nuclear reactions. We will discuss our emerging understanding of the convectively-unstable, neutrino-driven explosion mechanism, based on increasingly realistic neutrino radiation hydrodynamic simulations that include progressively better nuclear and particle physics. Multi-dimensional models with spectral neutrino transport from several research groups, which slowly develop successful explosions for a range of progenitors, have recently motivated changes in our understanding of the neutrino reheating mechanism. In a similar fashion, improvements in nuclear physics, most notably explorations of weak interactions on nuclei and the nuclear equation of state, continue to refine our understanding of the births of neutron stars and the supernovae that result. Recent progress on both the macroscopic and microscopic effects that affect core-collapse supernovae are discussed.

  17. Using Direct Metal Deposition to Fabricate Mold Plates for an Injection Mold Machine Allowing for the Evaluation of Cost Effective Near-Sourcing Opportunities in Larger, High Volume Consumer Products

    SciTech Connect (OSTI)

    Duty, Chad E; Groh, Bill

    2014-10-31

    ORNL collaborated with Radio Systems Corporation to investigate additive manufacturing (AM) of mold plates for plastic injection molding by direct metal deposition. The team s modelling effort identified a 100% improvement in heat transfer through use of conformal cooling lines that could be built into the mold using a revolutionary design enabled by additive manufacturing. Using the newly installed laser deposition system at the ORNL Manufacturing Demonstration Facility (MDF) a stainless steel mold core was printed.

  18. XT Node Architecture Let's Review: Dual Core v. Quad Core

    E-Print Network [OSTI]

    DDR2 · 10GB/s peak @ 667MHz · 8GB/s nominal STREAMs Quad Core · Core · 2.1Ghz clock frequency · SSE to L1,L2,L3 · Memory · Dual Channel DDR2 · 12GB/s peak @ 800MHz · 10GB/s nominal STREAMs #12;Cray XT4 Node 9.6 GB/sec 9.6GB/sec 9.6 GB/sec 9.6GB/sec 2 ­ 8 GB 12.8 GB/sec direct connect memory (DDR 800) 6

  19. Anisotropic Formation of Magnetized Cores in Turbulent Clouds

    E-Print Network [OSTI]

    Chen, Che-Yu

    2015-01-01

    In giant molecular clouds (GMCs), shocks driven by converging turbulent flows create high-density, strongly-magnetized regions that are locally sheetlike. In previous work, we showed that within these layers, dense filaments and embedded self-gravitating cores form by gathering material along the magnetic field lines. Here, we extend the parameter space of our three-dimensional, turbulent MHD core formation simulations. We confirm the anisotropic core formation model we previously proposed, and quantify the dependence of median core properties on the pre-shock inflow velocity and upstream magnetic field strength. Our results suggest that bound core properties are set by the total dynamic pressure (dominated by large-scale turbulence) and thermal sound speed c_s in GMCs, independent of magnetic field strength. For models with Mach number between 5 and 20, the median core masses and radii are comparable to the critical Bonnor-Ebert mass and radius defined using the dynamic pressure for P_ext. Our results corres...

  20. Dark solitons in dual-core waveguides with dispersive coupling

    E-Print Network [OSTI]

    Kartashov, Yaroslav V; Malomed, Boris A

    2015-01-01

    We report on new types of two-component one-dimensional dark solitons (DSs) in a model of a dual-core waveguide with normal group-velocity dispersion and Kerr nonlinearity in both cores, the coupling between which is dispersive too. In the presence of the dispersive coupling, quiescent DSs supported by the zero-frequency background are always gray, being stable with the out-of-phase background, i.e., for opposite signs of the fields in the cores. On the contrary, the background with a nonzero frequency supports quiescent black solitons which may be stable for both out- and in-phase backgrounds, if the dispersive coupling is sufficiently strong. Only DSs supported by the out-of-phase background admit an extension to the case of nonzero phase mismatch between the cores.

  1. 80 units of core courses 70 units of core courses 70 units of core courses 80 units of core courses Semester 1 Semester 1 Semester 1 Semester 1

    E-Print Network [OSTI]

    Fleming, Andrew J.

    80 units of core courses 70 units of core courses 70 units of core courses 80 units of core courses Semester 1 Semester 1 Semester 1 Semester 1 ARBE1303 10 units ARBE2101 10 units ARBE3100 10 units ARBE4101 10 units Introduction to the Construction Industry Construction Ecology 2 Construction Technology 3

  2. Reactor core isolation cooling system

    DOE Patents [OSTI]

    Cooke, F.E.

    1992-12-08

    A reactor core isolation cooling system includes a reactor pressure vessel containing a reactor core, a drywell vessel, a containment vessel, and an isolation pool containing an isolation condenser. A turbine is operatively joined to the pressure vessel outlet steamline and powers a pump operatively joined to the pressure vessel feedwater line. In operation, steam from the pressure vessel powers the turbine which in turn powers the pump to pump makeup water from a pool to the feedwater line into the pressure vessel for maintaining water level over the reactor core. Steam discharged from the turbine is channeled to the isolation condenser and is condensed therein. The resulting heat is discharged into the isolation pool and vented to the atmosphere outside the containment vessel for removing heat therefrom. 1 figure.

  3. Reactor core isolation cooling system

    DOE Patents [OSTI]

    Cooke, Franklin E. (San Jose, CA)

    1992-01-01

    A reactor core isolation cooling system includes a reactor pressure vessel containing a reactor core, a drywell vessel, a containment vessel, and an isolation pool containing an isolation condenser. A turbine is operatively joined to the pressure vessel outlet steamline and powers a pump operatively joined to the pressure vessel feedwater line. In operation, steam from the pressure vessel powers the turbine which in turn powers the pump to pump makeup water from a pool to the feedwater line into the pressure vessel for maintaining water level over the reactor core. Steam discharged from the turbine is channeled to the isolation condenser and is condensed therein. The resulting heat is discharged into the isolation pool and vented to the atmosphere outside the containment vessel for removing heat therefrom.

  4. Kansalliskirjasto Dublin Core Dublin Core metadataformaatin suomalainen versio

    E-Print Network [OSTI]

    Rodriguez, Carlos

    - Medical Subject Headings 3. DDC - Dewey Decimal Classification 4. LCC - Library of Congress Classification: - Merkintäjärjestelmät: #12;Kansalliskirjasto Dublin Core 2(6) 1. LCSH - Library of Congress Subject Headings 2. MESH 5. UDC - Universal Decimal Classification Suomalaiset merkintäjärjestelmät katso sfs_aihe.pdf Kuvaus

  5. Massive Quiescent Cores in Orion. -- II. Core Mass Function

    E-Print Network [OSTI]

    Li, D; Goldsmith, P F; Langer, W D

    2006-01-01

    We have surveyed submillimeter continuum emission from relatively quiescent regions in the Orion molecular cloud to determine how the core mass function in a high mass star forming region compares to the stellar initial mass function. Such studies are important for understanding the evolution of cores to stars, and for comparison to formation processes in high and low mass star forming regions. We used the SHARC II camera on the Caltech Submillimeter Observatory telescope to obtain 350 \\micron data having angular resolution of about 9 arcsec, which corresponds to 0.02 pc at the distance of Orion. Our analysis combining dust continuum and spectral line data defines a sample of 51 Orion molecular cores with masses ranging from 0.1 \\Ms to 46 \\Ms and a mean mass of 9.8 \\Ms, which is one order of magnitude higher than the value found in typical low mass star forming regions, such as Taurus. The majority of these cores cannot be supported by thermal pressure or turbulence, and are probably supercritical.They are th...

  6. The core mass growth and stellar lifetime of thermally pulsing asymptotic giant branch stars

    SciTech Connect (OSTI)

    Kalirai, Jason S.; Tremblay, Pier-Emmanuel; Marigo, Paola E-mail: paola.marigo@unipd.it

    2014-02-10

    We establish new constraints on the intermediate-mass range of the initial-final mass relation, and apply the results to study the evolution of stars on the thermally pulsing asymptotic giant branch (TP-AGB). These constraints derive from newly discovered (bright) white dwarfs in the nearby Hyades and Praesepe star clusters, including a total of 18 high signal-to-noise ratio measurements with progenitor masses of M {sub initial} = 2.8-3.8 M {sub ?}. We also include a new analysis of existing white dwarfs in the older NGC 6819 and NGC 7789 star clusters, M {sub initial} = 1.6 and 2.0 M {sub ?}. Over this range of initial masses, stellar evolutionary models for metallicity Z {sub initial} = 0.02 predict the maximum growth of the core of TP-AGB stars. By comparing the newly measured remnant masses to the robust prediction of the core mass at the first thermal pulse on the AGB (i.e., from stellar interior models), we establish several findings. First, we show that the stellar core mass on the AGB grows rapidly from 10% to 30% for stars with M {sub initial} = 1.6 to 2.0 M {sub ?}. At larger masses, the core-mass growth decreases steadily to ?10% at M {sub initial} = 3.4 M {sub ?}, after which there is a small hint of a upturn out to M {sub initial} = 3.8 M {sub ?}. These observations are in excellent agreement with predictions from the latest TP-AGB evolutionary models in Marigo et al. We also compare to models with varying efficiencies of the third dredge-up and mass loss, and demonstrate that the process governing the growth of the core is largely the stellar wind, while the third dredge-up plays a secondary, but non-negligible role. Based on the new white dwarf measurements, we perform an exploratory calibration of the most popular mass-loss prescriptions in the literature, as well as of the third dredge-up efficiency as a function of the stellar mass. Finally, we estimate the lifetime and the integrated luminosity of stars on the TP-AGB to peak at t ? 3 Myr and E = 1.2 × 10{sup 10} L {sub ?} yr for M {sub initial} ? 2 M {sub ?} (t ? 2 Myr for luminosities brighter than the red giant branch tip at log (L/L {sub ?}) > 3.4), decreasing to t = 0.4 Myr and E = 6.1 × 10{sup 9} L {sub ?} yr for stars with M {sub initial} ? 3.5 M {sub ?}. The implications of these results are discussed, especially with respect to general studies aimed at characterizing the integrated light output of TP-AGB stars in population synthesis models.

  7. Large core fiber optic cleaver

    DOE Patents [OSTI]

    Halpin, J.M.

    1996-03-26

    The present invention relates to a device and method for cleaving optical fibers which yields cleaved optical fiber ends possessing high damage threshold surfaces. The device can be used to cleave optical fibers with core diameters greater than 400 {micro}m. 30 figs.

  8. Chemflex Overview: Common Chemistry core

    E-Print Network [OSTI]

    Gilchrist, James F.

    Advanced chemistry laboratory I CHM 335 3 Advanced chemistry laboratory II Mat 33 3 Engineering materialsChemflex Overview: Common Chemistry core CHM 40, 41 (or CHM 30, 31) 8 Introductory chemistry CHM 110,111,112,113 8 Organic chemistry CHM 332 3 Analytical chemistry CHM 201*** 2 Technical writing CHM

  9. Large core fiber optic cleaver

    DOE Patents [OSTI]

    Halpin, John M. (Livermore, CA)

    1996-01-01

    The present invention relates to a device and method for cleaving optical fibers which yields cleaved optical fiber ends possessing high damage threshold surfaces. The device can be used to cleave optical fibers with core diameters greater than 400 .mu.m.

  10. Stability of Molten Core Materials

    SciTech Connect (OSTI)

    Layne Pincock; Wendell Hintze

    2013-01-01

    The purpose of this report is to document a literature and data search for data and information pertaining to the stability of nuclear reactor molten core materials. This includes data and analysis from TMI-2 fuel and INL’s LOFT (Loss of Fluid Test) reactor project and other sources.

  11. Logging-while-coring method and apparatus

    DOE Patents [OSTI]

    Goldberg, David S.; Myers, Gregory J.

    2007-01-30

    A method and apparatus for downhole coring while receiving logging-while-drilling tool data. The apparatus includes core collar and a retrievable core barrel. The retrievable core barrel receives core from a borehole which is sent to the surface for analysis via wireline and latching tool The core collar includes logging-while-drilling tools for the simultaneous measurement of formation properties during the core excavation process. Examples of logging-while-drilling tools include nuclear sensors, resistivity sensors, gamma ray sensors, and bit resistivity sensors. The disclosed method allows for precise core-log depth calibration and core orientation within a single borehole, and without at pipe trip, providing both time saving and unique scientific advantages.

  12. Logging-while-coring method and apparatus

    DOE Patents [OSTI]

    Goldberg, David S. (New York, NY); Myers, Gregory J. (Cornwall, NY)

    2007-11-13

    A method and apparatus for downhole coring while receiving logging-while-drilling tool data. The apparatus includes core collar and a retrievable core barrel. The retrievable core barrel receives core from a borehole which is sent to the surface for analysis via wireline and latching tool The core collar includes logging-while-drilling tools for the simultaneous measurement of formation properties during the core excavation process. Examples of logging-while-drilling tools include nuclear sensors, resistivity sensors, gamma ray sensors, and bit resistivity sensors. The disclosed method allows for precise core-log depth calibration and core orientation within a single borehole, and without at pipe trip, providing both time saving and unique scientific advantages.

  13. Angular Momentum of the N2H+ Cores in the Orion A Cloud

    E-Print Network [OSTI]

    Tatematsu, Ken'ichi; Sanhueza, Patricio; Luong, Quang Nguyen; Umemoto, Tomofumi; Mizuno, Norikazu

    2016-01-01

    We have analyzed the angular momentum of the molecular cloud cores in the Orion A giant molecular cloud observed in the N2H+ J = 1-0 line with the Nobeyama 45 m radio telescope. We have measured the velocity gradient using position velocity diagrams passing through core centers, and made sinusoidal fitting against the position angle. 27 out of 34 N2H+ cores allowed us to measure the velocity gradient without serious confusion. The derived velocity gradient ranges from 0.5 to 7.8 km/s/pc. We marginally found that the specific angular momentum J/M (against the core radius R) of the Orion N2H+ cores tends to be systematically larger than that of molecular cloud cores in cold dark clouds obtained by Goodman et al., in the J/M-R relation. The ratio beta of rotational to gravitational energy is derived to be beta = 10^{-2.3+/-0.7}, and is similar to that obtained for cold dark cloud cores in a consistent definition. The large-scale rotation of the integral-shaped filament of the Orion A giant molecular cloud does n...

  14. Extended core for motor/generator

    DOE Patents [OSTI]

    Shoykhet, Boris A.

    2006-08-22

    An extended stator core in a motor/generator can be utilized to mitigate losses in end regions of the core and a frame of the motor/generator. To mitigate the losses, the stator core can be extended to a length substantially equivalent to or greater than a length of a magnetically active portion in the rotor. Alternatively, a conventional length stator core can be utilized with a shortened magnetically active portion to mitigate losses in the motor/generator. To mitigate the losses in the core caused by stator winding, the core can be extended to a length substantially equivalent or greater than a length of stator winding.

  15. Extended core for motor/generator

    DOE Patents [OSTI]

    Shoykhet, Boris A.

    2005-05-10

    An extended stator core in a motor/generator can be utilized to mitigate losses in end regions of the core and a frame of the motor/generator. To mitigate the losses, the stator core can be extended to a length substantially equivalent to or greater than a length of a magnetically active portion in the rotor. Alternatively, a conventional length stator core can be utilized with a shortened magnetically active portion to mitigate losses in the motor/generator. To mitigate the losses in the core caused by stator winding, the core can be extended to a length substantially equivalent or greater than a length of stator winding.

  16. Challenges in forming the solar system's giant planet cores via pebble accretion

    SciTech Connect (OSTI)

    Kretke, K. A.; Levison, H. F., E-mail: kretke@boulder.swri.edu [Southwest Research Institute, 1050 Walnut Street, Suite 300, Boulder, CO 80302 (United States)

    2014-12-01

    Though ?10 M {sub ?} mass rocky/icy cores are commonly held as a prerequisite for the formation of gas giants, theoretical models still struggle to explain how these embryos can form within the lifetimes of gaseous circumstellar disks. In recent years, aerodynamic-aided accretion of 'pebbles', objects ranging from centimeters to meters in size, has been suggested as a potential solution to this long-standing problem. While pebble accretion has been demonstrated to be extremely effective in local simulations that look at the detailed behavior of these pebbles in the vicinity of a single planetary embryo, to date there have been no global simulations demonstrating the effectiveness of pebble accretion in a more complicated, multi-planet environment. Therefore, we have incorporated the aerodynamic-aided accretion physics into LIPAD, a Lagrangian code that can follow the collisional/accretional/dynamical evolution of a protoplanetary system, to investigate how pebble accretion manifests itself in the larger planet formation picture. We find that under generic circumstances, pebble accretion naturally leads to an 'oligarchic' type of growth in which a large number of planetesimals grow to similar-sized planets. In particular, our simulations tend to form hundreds of Mars- and Earth-mass objects between 4 and 10 AU. While merging of some oligarchs may grow massive enough to form giant planet cores, leftover oligarchs lead to planetary systems that cannot be consistent with our own solar system. We investigate various ideas presented in the literature (including evaporation fronts and planet traps) and find that none easily overcome this tendency toward oligarchic growth.

  17. Analysis and Stability of Bent–Core Liquid Crystal Fibers

    E-Print Network [OSTI]

    2011-02-21

    Feb 21, 2011 ... In this paper we analyze a free–boundary model for free–standing fibers made from smectic layers of kinked (bent–core) liquid crystal molecules. ...... The elastic term is the smallest of the three in modulus, however all are of.

  18. Laminated electromagnetic pump stator core

    DOE Patents [OSTI]

    Fanning, A.W.

    1995-08-08

    A stator core for an electromagnetic pump includes a plurality of circumferentially abutting tapered laminations extending radially outwardly from a centerline axis to collectively define a radially inner bore and a radially outer circumference. Each of the laminations includes radially inner and outer edges and has a thickness increasing from the inner edge toward the outer edge to provide a substantially continuous path adjacent the circumference. This pump is used in nuclear fission reactors. 19 figs.

  19. Coring in deep hardrock formations

    SciTech Connect (OSTI)

    Drumheller, D.S.

    1988-08-01

    The United States Department of Energy is involved in a variety of scientific and engineering feasibility studies requiring extensive drilling in hard crystalline rock. In many cases well depths extend from 6000 to 20,000 feet in high-temperature, granitic formations. Examples of such projects are the Hot Dry Rock well system at Fenton Hill, New Mexico and the planned exploratory magma well near Mammoth Lakes, California. In addition to these programs, there is also continuing interest in supporting programs to reduce drilling costs associated with the production of geothermal energy from underground sources such as the Geysers area near San Francisco, California. The overall progression in these efforts is to drill deeper holes in higher temperature, harder formations. In conjunction with this trend is a desire to improve the capability to recover geological information. Spot coring and continuous coring are important elements in this effort. It is the purpose of this report to examine the current methods used to obtain core from deep wells and to suggest projects which will improve existing capabilities. 28 refs., 8 figs., 2 tabs.

  20. may also explain the larger extent of quiet Sun spicules1,2 mode power and granular flows are stronger by up to 50% and

    E-Print Network [OSTI]

    Johnson, Peter D.

    may also explain the larger extent of quiet Sun spicules1,2 where p- mode power and granular flows 2004; doi:10.1038/nature02749. 1. Beckers, J. M. Solar spicules. Sol. Phys. 3, 367­433 (1968). 2. Beckers, J. M. Solar spicules. Annu. Rev. Astron. Astrophys. 10, 73­100 (1972). 3. Sterling, A. C. Solar

  1. atoms diffusing rapidly among the six sites. In contrast to the 2V clusters, the larger 3V clusters are active for H2 dissociation (Fig. 2c).

    E-Print Network [OSTI]

    Romanowicz, Barbara

    . & Olsen, R. A. Adsorption energies and ordered structures of hydrogen on Pd(111) from density functional. C. & Van Hove, M. A. Location of hydrogen on palladium (111) studied by low- energy electron to 5V clusters. Hydrogen adsorption was frequently observed for 3V and larger clusters, always reducing

  2. Granular Dynamics in Pebble Bed Reactor Cores

    E-Print Network [OSTI]

    Laufer, Michael Robert

    2013-01-01

    a simulant fluid to match the dynamics of fuel pebbles andfuel pebbles through reactor cores with and without coupled fluid

  3. Distortion of a Steel Cylinder Casting with a Core D. Galles and C. Beckermann

    E-Print Network [OSTI]

    Beckermann, Christoph

    contraction to introduce stresses and distortions. Therefore, deformation models of both the steel and mold process; the measurements show that thermal expansions (of both the outer mold and core) have an immediate are predicted in the core and casting; the results suggest 1) the thermal expansion coefficient of the mold

  4. Short wavelength topography on the inner-core boundary

    E-Print Network [OSTI]

    Cao, A.; Masson, Y.; Romanowicz, B.

    2006-01-01

    Short wavelength topography on the inner-core boundary Aimin94720 Constraining the topography of the inner-core boundaryindicates the presence of topography at the inner- core

  5. Generator stator core vent duct spacer posts

    DOE Patents [OSTI]

    Griffith, John Wesley (Schenectady, NY); Tong, Wei (Clifton Park, NY)

    2003-06-24

    Generator stator cores are constructed by stacking many layers of magnetic laminations. Ventilation ducts may be inserted between these layers by inserting spacers into the core stack. The ventilation ducts allow for the passage of cooling gas through the core during operation. The spacers or spacer posts are positioned between groups of the magnetic laminations to define the ventilation ducts. The spacer posts are secured with longitudinal axes thereof substantially parallel to the core axis. With this structure, core tightness can be assured while maximizing ventilation duct cross section for gas flow and minimizing magnetic loss in the spacers.

  6. Gravitational wave extraction in simulations of rotating stellar core collapse

    SciTech Connect (OSTI)

    Reisswig, C.; Ott, C. D.; Sperhake, U.; Schnetter, E.

    2011-03-15

    We perform simulations of general relativistic rotating stellar core collapse and compute the gravitational waves (GWs) emitted in the core-bounce phase of three representative models via multiple techniques. The simplest technique, the quadrupole formula (QF), estimates the GW content in the spacetime from the mass-quadrupole tensor only. It is strictly valid only in the weak-field and slow-motion approximation. For the first time, we apply GW extraction methods in core collapse that are fully curvature based and valid for strongly radiating and highly relativistic sources. These techniques are not restricted to weak-field and slow-motion assumptions. We employ three extraction methods computing (i) the Newman-Penrose (NP) scalar {Psi}{sub 4}, (ii) Regge-Wheeler-Zerilli-Moncrief master functions, and (iii) Cauchy-characteristic extraction (CCE) allowing for the extraction of GWs at future null infinity, where the spacetime is asymptotically flat and the GW content is unambiguously defined. The latter technique is the only one not suffering from residual gauge and finite-radius effects. All curvature-based methods suffer from strong nonlinear drifts. We employ the fixed-frequency integration technique as a high-pass waveform filter. Using the CCE results as a benchmark, we find that finite-radius NP extraction yields results that agree nearly perfectly in phase, but differ in amplitude by {approx}1%-7% at core bounce, depending on the model. Regge-Wheeler-Zerilli-Moncrief waveforms, while, in general, agreeing in phase, contain spurious high-frequency noise of comparable amplitudes to those of the relatively weak GWs emitted in core collapse. We also find remarkably good agreement of the waveforms obtained from the QF with those obtained from CCE. The results from QF agree very well in phase and systematically underpredict peak amplitudes by {approx}5%-11%, which is comparable to the NP results and is certainly within the uncertainties associated with core collapse physics.

  7. Core Values | The Ames 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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would like submit the followingConcentratingPortalCool MagneticCopper Palladium-Core

  8. Core Analysis | 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 Home Page on QA:QA J-E-1 SECTION J APPENDIX ECoopButtePower Ventures JumpCommercialRenewableGlobal LInformationCore Analysis

  9. Core refueling subsystem design description. Revision 1

    SciTech Connect (OSTI)

    Anderson, J.K.; Harvey, E.C.

    1987-07-01

    The Core Refueling Subsystem of the Fuel Handling and Storage System provides the mechanisms and tools necessary for the removal and replacement of the hexagonal elements which comprise the reactor core. The Core Refueling Subsystem is not "safety-related." The Core Refueling Subsystem equipment is used to prepare the plant for element removal and replacement, install the machines which handle the elements, maintain control of air inleakage and radiation release, transport the elements between the core and storage, and control the automatic and manual operations of the machines. Much of the element handling is performed inside the vessel, and the entire exchange of elements between storage and core is performed with the elements in a helium atmosphere. The core refueling operations are conducted with the reactor module shutdown and the primary coolant pressure slightly subatmospheric. The subsystem is capable of accomplishing the refueling in a reliable manner commensurate with the plant availability requirements.

  10. Toward connecting core-collapse supernova theory with observations. I. Shock revival in a 15 M {sub ?} blue supergiant progenitor with SN 1987A energetics

    SciTech Connect (OSTI)

    Handy, Timothy; Plewa, Tomasz [Department of Scientific Computing, Florida State University, Tallahassee, FL 32306 (United States); Odrzywo?ek, Andrzej, E-mail: tplewa@fsu.edu [Marian Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Cracow (Poland)

    2014-03-10

    We study the evolution of the collapsing core of a 15 M {sub ?} blue supergiant supernova progenitor from the core bounce until 1.5 s later. We present a sample of hydrodynamic models parameterized to match the explosion energetics of SN 1987A. We find the spatial model dimensionality to be an important contributing factor in the explosion process. Compared to two-dimensional (2D) simulations, our three-dimensional (3D) models require lower neutrino luminosities to produce equally energetic explosions. We estimate that the convective engine in our models is 4% more efficient in 3D than in 2D. We propose that the greater efficiency of the convective engine found in 3D simulations might be due to the larger surface-to-volume ratio of convective plumes, which aids in distributing energy deposited by neutrinos. We do not find evidence of the standing accretion shock instability or turbulence being a key factor in powering the explosion in our models. Instead, the analysis of the energy transport in the post-shock region reveals characteristics of penetrative convection. The explosion energy decreases dramatically once the resolution is inadequate to capture the morphology of convection on large scales. This shows that the role of dimensionality is secondary to correctly accounting for the basic physics of the explosion. We also analyze information provided by particle tracers embedded in the flow and find that the unbound material has relatively long residency times in 2D models, while in 3D a significant fraction of the explosion energy is carried by particles with relatively short residency times.

  11. Development of Toroidal Core Transformers

    SciTech Connect (OSTI)

    Leon, Francisco

    2014-05-31

    The original objective of this project was to design, build and test a few prototypes of singlephase dry-type distribution transformers of 25 kVA, 2.4 kV primary to 120 V transformers using cores made of a continuous steel strip shaped like a doughnut (toroid). At different points during the development of the project, the scope was enhanced to include the more practical case of a 25 kVA transformer for a 13.8 kV primary system voltage. Later, the scope was further expanded to design and build a 50 kVA unit to transformer voltage from 7.62 kV to 2x120 V. This is a common transformer used by Con Edison of New York and they are willing to test it in the field. The project officially started in September 2009 and ended in May 2014. The progress was reported periodically to DOE in eighteen quarterly reports. A Continuation Application was submitted to DOE in June 2010. In May 2011 we have requested a non-cost extension of the project. In December 2011, the Statement of Project Objectives (SOPO) was updated to reflect the real conditions and situation of the project as of 2011. A second Continuation Application was made and funding was approved in 2013 by DOE and the end date was extended to May 2014.The technical challenges that were overcome in this project include: the development of the technology to pass the impulse tests, derive a model for the thermal performance, produce a sound mechanical design, and estimate the inrush current. However, the greatest challenge that we faced during the development of the project was the complications of procuring the necessary parts and materials to build the transformers. The actual manufacturing process is relatively fast, but getting all parts together is a very lengthy process. The main products of this project are two prototypes of toroidal distribution transformers of 7.62 kV (to be used in a 13.8 kV system) to 2x120 V secondary (standard utilization voltage); one is rated at 25 kVA and the other at 50 kVA. The 25 kVA transformer passed the impulse test in KEMA high-voltage laboratories. Additional products include: nine papers published in the IEEE Transactions on Power Delivery, one patent has been filed, three PhD students were supported from beginning to graduation, five postdoctoral fellows, and three MSc students were partially supported. The electrical characteristics of our dry-type toroidal transformers are similar to those of the oil-immersed pole mounted transformers currently in use by many utilities, but toroids have higher efficiency. The no-load losses of the 50 kVA prototype are only 45 W. A standard transformer has no-load losses between 90 and 240 W. Thus, even the finest transformer built today with standard technology has double the amount of no-load losses than the prototype toroidal transformer. When the manufacturing process is prepared for mass production, the cost of a dry-type toroidal transformer would be similar to the price of an oil-filed standard design. However, because of the greatly reduced losses, the total ownership cost of a toroidal transformer could be about half of a traditional design. We got a grant from Power Bridge NY in the amount of $149,985 from June 2014 to May 2015 to continue developing the transformer with commercialization objectives. We are considering the possibility to incorporate a company to manufacture the transformers and have contacted investors. The current status of the real life testing is as follows: after several months of silence, Con Edison has re-started conversations and has shown willingness to test the transformer. Other companies, PSE&G and National Grid have recently also shown interest and we will present our product to them soon.

  12. Cool Core Clusters from Cosmological Simulations

    E-Print Network [OSTI]

    Rasia, E; Murante, G; Planelles, S; Beck, A M; Biffi, V; Ragone-Figueroa, C; Granato, G L; Steinborn, L K; Dolag, K

    2015-01-01

    We present results obtained from a set of cosmological hydrodynamic simulations of galaxy clusters, aimed at comparing predictions with observational data on the diversity between cool-core and non-cool-core clusters. Our simulations include the effects of stellar and AGN feedback and are based on an improved version of the Smoothed-Particle-Hydrodynamics code GADGET-3, which ameliorates gas mixing and better captures gas-dynamical instabilities by including a suitable artificial thermal diffusion. In this Letter, we focus our analysis on the entropy profiles, our primary diagnostic to classify the degree of cool-coreness of clusters, and on the iron profiles. In keeping with observations, our simulated clusters display a variety of behaviors in entropy profiles: they range from steadily decreasing profiles at small radii, characteristic of cool-core systems, to nearly flat core isentropic profiles, characteristic of non cool-core systems. Using observational criteria to distinguish between the two classes of...

  13. Revised 60-day safety screening and ferrocyanide results for tank 241-BY-108, rotary samples core 98 and core 104

    SciTech Connect (OSTI)

    Baldwin, J.H.

    1996-02-01

    Revised Report for 60-Day Safety Screening Results, Rotary Samples Core 98 and Core 104, Safety Screening and Ferrocyanide Results.

  14. Final Report for the "Fusion Application for Core-Edge Transport Simulations (FACETS)"

    SciTech Connect (OSTI)

    Cary, John R; Kruger, Scott

    2014-10-02

    The FACETS project over its lifetime developed the first self-consistent core-edge coupled capabilities, a new transport solver for modeling core transport in tokamak cores, developed a new code for modeling wall physics over long time scales, and significantly improved the capabilities and performance of legacy components, UEDGE, NUBEAM, GLF23, GYRO, and BOUT++. These improved capabilities leveraged the team’s expertise in applied mathematics (solvers and algorithms) and computer science (performance improvements and language interoperability). The project pioneered new methods for tackling the complexity of simulating the concomitant complexity of tokamak experiments.

  15. Experimental and Analytic Study on the Core Bypass Flow in a Very High Temperature Reactor

    SciTech Connect (OSTI)

    Richard Schultz

    2012-04-01

    Core bypass flow has been one of key issues in the very high temperature reactor (VHTR) design for securing core thermal margins and achieving target temperatures at the core exit. The bypass flow in a prismatic VHTR core occurs through the control element holes and the radial and axial gaps between the graphite blocks for manufacturing and refueling tolerances. These gaps vary with the core life cycles because of the irradiation swelling/shrinkage characteristic of the graphite blocks such as fuel and reflector blocks, which are main components of a core's structure. Thus, the core bypass flow occurs in a complicated multidimensional way. The accurate prediction of this bypass flow and counter-measures to minimize it are thus of major importance in assuring core thermal margins and securing higher core efficiency. Even with this importance, there has not been much effort in quantifying and accurately modeling the effect of the core bypass flow. The main objectives of this project were to generate experimental data for validating the software to be used to calculate the bypass flow in a prismatic VHTR core, validate thermofluid analysis tools and their model improvements, and identify and assess measures for reducing the bypass flow. To achieve these objectives, tasks were defined to (1) design and construct experiments to generate validation data for software analysis tools, (2) determine the experimental conditions and define the measurement requirements and techniques, (3) generate and analyze the experimental data, (4) validate and improve the thermofluid analysis tools, and (5) identify measures to control the bypass flow and assess its performance in the experiment.

  16. Material with core-shell structure

    DOE Patents [OSTI]

    Luhrs, Claudia (Rio Rancho, NM); Richard, Monique N. (Ann Arbor, MI); Dehne, Aaron (Maumee, OH); Phillips, Jonathan (Rio Rancho, NM); Stamm, Kimber L. (Ann Arbor, MI); Fanson, Paul T. (Brighton, MI)

    2011-11-15

    Disclosed is a material having a composite particle, the composite particle including an outer shell and a core. The core is made from a lithium alloying material and the outer shell has an inner volume that is greater in size than the core of the lithium alloying material. In some instances, the outer mean diameter of the outer shell is less than 500 nanometers and the core occupies between 5 and 99% of the inner volume. In addition, the outer shell can have an average wall thickness of less than 100 nanometers.

  17. December 2011 | 41 Suspended Core Subwavelength

    E-Print Network [OSTI]

    Skorobogatiy, Maksim

    fabricated a polyethylene microstructured fiber featuring a subwavelength-size core suspended by very thin shielded from the environment. e experimental modal field distributions were also well reproduced

  18. Chiral and Antichiral Order in Bent-Core Liquid Crystals

    E-Print Network [OSTI]

    Jonathan V. Selinger

    2003-03-18

    Recent experiments have found a bent-core liquid crystal in which the layer chirality alternates from layer to layer, giving a racemic or "antichiral" material, even though the molecules are uniformly chiral. To explain this effect, we map the liquid crystal onto an Ising model, analogous to a model for chiral order in polymers. We calculate the phase diagram for this model, and show that it has a second-order phase transition between antichiral order and homogeneous chiral order. We discuss how this transition can be studied by further chemical synthesis or by doping experiments.

  19. Multi-core and Many-core Shared-memory Parallel Raycasting Volume Rendering Optimization and Tuning

    SciTech Connect (OSTI)

    Howison, Mark

    2012-01-31

    Given the computing industry trend of increasing processing capacity by adding more cores to a chip, the focus of this work is tuning the performance of a staple visualization algorithm, raycasting volume rendering, for shared-memory parallelism on multi-core CPUs and many-core GPUs. Our approach is to vary tunable algorithmic settings, along with known algorithmic optimizations and two different memory layouts, and measure performance in terms of absolute runtime and L2 memory cache misses. Our results indicate there is a wide variation in runtime performance on all platforms, as much as 254% for the tunable parameters we test on multi-core CPUs and 265% on many-core GPUs, and the optimal configurations vary across platforms, often in a non-obvious way. For example, our results indicate the optimal configurations on the GPU occur at a crossover point between those that maintain good cache utilization and those that saturate computational throughput. This result is likely to be extremely difficult to predict with an empirical performance model for this particular algorithm because it has an unstructured memory access pattern that varies locally for individual rays and globally for the selected viewpoint. Our results also show that optimal parameters on modern architectures are markedly different from those in previous studies run on older architectures. And, given the dramatic performance variation across platforms for both optimal algorithm settings and performance results, there is a clear benefit for production visualization and analysis codes to adopt a strategy for performance optimization through auto-tuning. These benefits will likely become more pronounced in the future as the number of cores per chip and the cost of moving data through the memory hierarchy both increase.

  20. Experimental Criticality Benchmarks for SNAP 10A/2 Reactor Cores

    SciTech Connect (OSTI)

    Krass, A.W.

    2005-12-19

    This report describes computational benchmark models for nuclear criticality derived from descriptions of the Systems for Nuclear Auxiliary Power (SNAP) Critical Assembly (SCA)-4B experimental criticality program conducted by Atomics International during the early 1960's. The selected experimental configurations consist of fueled SNAP 10A/2-type reactor cores subject to varied conditions of water immersion and reflection under experimental control to measure neutron multiplication. SNAP 10A/2-type reactor cores are compact volumes fueled and moderated with the hydride of highly enriched uranium-zirconium alloy. Specifications for the materials and geometry needed to describe a given experimental configuration for a model using MCNP5 are provided. The material and geometry specifications are adequate to permit user development of input for alternative nuclear safety codes, such as KENO. A total of 73 distinct experimental configurations are described.

  1. Neutrinos and nucleosynthesis in core-collapse supernovae

    SciTech Connect (OSTI)

    Fröhlich, C.; Casanova, J. [Department of Physics, North Carolina State University, Raleigh, NC, 27695 (United States); Hempel, M.; Liebendörfer, M. [Departement für Physik, Universität Basel, CH-4056 Basel (Switzerland); Melton, C. A. [Department of Physics, North Carolina State University, Raleigh, NC 27695 (United States); Perego, A. [Institut für Kernphysik, Technische Universität Darmstadt, D-64289 Darmstadt (Germany)

    2014-01-01

    Massive stars (M > 8-10 M{sub ?}) undergo core collapse at the end of their life and explode as supernova with ~ 10?¹ erg of kinetic energy. While the detailed supernova explosion mechanism is still under investigation, reliable nucleosynthesis calculations based on successful explosions are needed to explain the observed abundances in metal-poor stars and to predict supernova yields for galactic chemical evolution studies. To predict nucleosynthesis yields for a large number of progenitor stars, computationally efficient explosion models are required. We model the core collapse, bounce and subsequent explosion of massive stars assuming spherical symmetry and using detailed microphysics and neutrino physics combined with a novel method to artificially trigger the explosion (PUSH). We discuss the role of neutrinos, the conditions in the ejecta, and the resulting nucleosynthesis.

  2. Magnetized neutron stars with superconducting cores: Effect of entrainment

    E-Print Network [OSTI]

    Palapanidis, K; Lander, S K

    2015-01-01

    We construct equilibrium configurations of magnetized, two-fluid neutron stars using an iterative numerical method. We assume that the neutron star has two regions: the core, which is modelled as a two-component fluid consisting of type-II superconducting protons and superfluid neutrons, and the crust, a region composed of normal matter. Taking a new step towards more complete equilibrium models, we include the effect of entrainment, which implies that a magnetic force acts on neutrons, too. We consider purely poloidal field cases and present improvements to an earlier numerical scheme for solving equilibrium equations, by introducing new convergence criteria. We find that entrainment results in qualitative differences in the structure of field lines across the crust-core boundary and along the magnetic axis.

  3. System design description for GCFR-core flow test loop

    SciTech Connect (OSTI)

    Huntley, W.R.; Grindell, A.G.

    1980-12-01

    The Core Flow Test Loop is a high-pressure, high-temperature, out-of-reactor helium circulation system that is being constructed to permit detailed study of the thermomechanical and thermal performance at prototypic steady-state and transient operating conditions of simulated segments of core assemblies for a GCFR Demonstration Plant, as designed by General Atomic Company. It will also permit the expermental verification of predictive analytical models of the GCFR core assemblies needed to reduce operational and safety uncertainties of the GCFR. Full-sized blanket assemblies and segments of fuel rod and control rod fuel assemblies will be simulated with test bundles of electrically powered fuel rod or blanket rod simulators. The loop will provide the steady-state and margin test requirements of bundle power and heat removal, and of helium coolant flow rate, pressure, and temperature for test bundles having up to 91 rods; these requirements set the maximum power, coolant helium flow, and thermal requirements for the loop. However, the size of the test vessel that contains the test bundles will be determined by the bundles that simulate a full-sized GCFR blanket assembly. The loop will also provide for power and coolant transients to simulate transient operation of GCFR core assemblies, including the capability for rapid helium depressurization to simulate the depressurization class of GCFR accidents. In addition, the loop can be used as an out-of-reactor test bed for characterizing in-reactor test bundle configurations.

  4. Sensitivity of IceCube-DeepCore to neutralino dark matter in the MSSM-25

    E-Print Network [OSTI]

    Hamish Silverwood; Pat Scott; Matthias Danninger; Christopher Savage; Joakim Edsjö; Jenni Adams; Anthony M Brown; Klas Hultqvist

    2013-04-17

    We analyse the sensitivity of IceCube-DeepCore to annihilation of neutralino dark matter in the solar core, generated within a 25 parameter version of the minimally supersymmetric standard model (MSSM-25). We explore the 25-dimensional parameter space using scanning methods based on importance sampling and using DarkSUSY 5.0.6 to calculate observables. Our scans produced a database of 6.02 million parameter space points with neutralino dark matter consistent with the relic density implied by WMAP 7-year data, as well as with accelerator searches. We performed a model exclusion analysis upon these points using the expected capabilities of the IceCube-DeepCore Neutrino Telescope. We show that IceCube-DeepCore will be sensitive to a number of models that are not accessible to direct detection experiments such as SIMPLE, COUPP and XENON100, indirect detection using Fermi-LAT observations of dwarf spheroidal galaxies, nor to current LHC searches.

  5. Sensitivity of IceCube-DeepCore to neutralino dark matter in the MSSM-25

    SciTech Connect (OSTI)

    Silverwood, Hamish; Adams, Jenni; Brown, Anthony M; Scott, Pat; Danninger, Matthias; Savage, Christopher; Edsjö, Joakim; Hultqvist, Klas E-mail: patscott@physics.mcgill.ca E-mail: savage@physics.utah.edu E-mail: jenni.adams@canterbury.ac.nz E-mail: klas.hultqvist@fysik.su.se

    2013-03-01

    We analyse the sensitivity of IceCube-DeepCore to annihilation of neutralino dark matter in the solar core, generated within a 25 parameter version of the minimally supersymmetric standard model (MSSM-25). We explore the 25-dimensional parameter space using scanning methods based on importance sampling and using DarkSUSY 5.0.6 to calculate observables. Our scans produced a database of 6.02 million parameter space points with neutralino dark matter consistent with the relic density implied by WMAP 7-year data, as well as with accelerator searches. We performed a model exclusion analysis upon these points using the expected capabilities of the IceCube-DeepCore Neutrino Telescope. We show that IceCube-DeepCore will be sensitive to a number of models that are not accessible to direct detection experiments such as SIMPLE, COUPP and XENON100, indirect detection using Fermi-LAT observations of dwarf spheroidal galaxies, nor to current LHC searches.

  6. Chapter 13. Exploring Use of the Reserved Core

    SciTech Connect (OSTI)

    Holmen, John; Humphrey, Alan; Berzins, Martin

    2015-07-29

    In this chapter, we illustrate benefits of thinking in terms of thread management techniques when using a centralized scheduler model along with interoperability of MPI and PThread. This is facilitated through an exploration of thread placement strategies for an algorithm modeling radiative heat transfer with special attention to the 61st core. This algorithm plays a key role within the Uintah Computational Framework (UCF) and current efforts taking place at the University of Utah to model next-generation, large-scale clean coal boilers. In such simulations, this algorithm models the dominant form of heat transfer and consumes a large portion of compute time. Exemplified by a real-world example, this chapter presents our early efforts in porting a key portion of a scalability-centric codebase to the Intel Xeon Phi coprocessor. Specifically, this chapter presents results from our experiments profiling the native execution of a reverse Monte-Carlo ray tracing-based radiation model on a single coprocessor. These results demonstrate that our fastest run configurations utilized the 61st core and that performance was not profoundly impacted when explicitly oversubscribing the coprocessor operating system thread. Additionally, this chapter presents a portion of radiation model source code, a MIC-centric UCF cross-compilation example, and less conventional thread management technique for developers utilizing the PThreads threading model.

  7. Core Science Requirement Final Document Page 1 THE CORE SCIENCE REQUIREMENT and

    E-Print Network [OSTI]

    Frey, Jesse C.

    Core Science Requirement ­ Final Document ­ Page 1 THE CORE SCIENCE REQUIREMENT and MENDEL SCIENCE EXPERIENCE COURSES Core requirement of 2 semesters of science with laboratory; requirement to be met by the end of the sophomore year Rationale Science literacy is an integral part of the intellectual

  8. UNL Core for Applied Genomics and Ecology

    E-Print Network [OSTI]

    Farritor, Shane

    UNL Core for Applied Genomics and Ecology Bioinformatics training Roche 454 GS-FLX Registration, Microbiomes, Variant Analysis, Whole Genomes, Transcriptomes Data Analysis and Statistics CAGE database and employer. University of Nebraska-Lincoln*Core for Applied Genomics and Ecology* 323 Filley Hall *Lincoln

  9. Idealized Test Cases for Dynamical Core Experiments

    E-Print Network [OSTI]

    Jablonowski, Christiane

    Idealized Test Cases for Dynamical Core Experiments Christiane Jablonowski (University of Michigan-13/2006 #12;Motivation · Test cases for 3D dynamical cores on the sphere ­ are hard to find in the literature groups ­ lack standardized & easy-to-use analysis techniques · Idea: Establish a collection of test cases

  10. UW-Milwaukee Strategic Planning Core Team

    E-Print Network [OSTI]

    Saldin, Dilano

    UW-Milwaukee Strategic Planning Core Team MINUTES November 19, 2012 Regents Room, Chapman Hall, 10 Strategic Planning Core team with oversight, coordination, and providing campus leadership with strategic plan, per the planning document. Last campus strategic plan was developed in 1996. b. Provost J. Britz

  11. Module Handbook Core Univ. of Oldenburg

    E-Print Network [OSTI]

    Habel, Annegret

    /EUREC Course 2008/2009 #12;EUREC Core Courses at University of Oldenburg, 1st Semester Wind Energy Module Module Description: Wind Energy Field: Core Oldenburg Courses: Wind Energy Wind Energy Technology Wind Energy Conversion (Lab) Excursion Tutorial Study Semester: First Semester Module

  12. Core sampling system spare parts assessment

    SciTech Connect (OSTI)

    Walter, E.J.

    1995-04-04

    Soon, there will be 4 independent core sampling systems obtaining samples from the underground tanks. It is desirable that these systems be available for sampling during the next 2 years. This assessment was prepared to evaluate the adequacy of the spare parts identified for the core sampling system and to provide recommendations that may remediate overages or inadequacies of spare parts.

  13. Method and apparatus for recovering unstable cores

    DOE Patents [OSTI]

    McGuire, Patrick L. (Los Alamos, NM); Barraclough, Bruce L. (Los Alamos, NM)

    1983-01-01

    A method and apparatus suitable for stabilizing hydrocarbon cores are given. Such stabilized cores have not previously been obtainable for laboratory study, and such study is believed to be required before the hydrate reserves can become a utilizable resource. The apparatus can be built using commercially available parts and is very simple and safe to operate.

  14. Moving core beam energy absorber and converter

    DOE Patents [OSTI]

    Degtiarenko, Pavel V.

    2012-12-18

    A method and apparatus for the prevention of overheating of laser or particle beam impact zones through the use of a moving-in-the-coolant-flow arrangement for the energy absorbing core of the device. Moving of the core spreads the energy deposition in it in 1, 2, or 3 dimensions, thus increasing the effective cooling area of the device.

  15. Pre-supernova neutrino emissions from ONe cores in the progenitors of core-collapse supernovae: are they distinguishable from those of Fe cores?

    E-Print Network [OSTI]

    Kato, Chinami; Yamada, Shoichi; Takahashi, Koh; Umeda, Hideyuki; Yoshida, Takashi; Ishidoshiro, Koji

    2015-01-01

    Aiming to distinguish two types of progenitors of core collapse supernovae, i.e., one with a core composed mainly of oxygen and neon (abbreviated as ONe core) and the other with an iron core (or Fe core), we calculated the luminosities and spectra of neutrinos emitted from these cores prior to gravitational collapse, taking neutrino oscillation into account. We found that the total energies emitted as $\\bar{\

  16. The impact of cell site re-homing on the performance of umts core networks

    E-Print Network [OSTI]

    Ouyang, Ye; 10.5121/ijngn.2010.2105

    2010-01-01

    Mobile operators currently prefer optimizing their radio networks via re-homing or cutting over the cell sites in 2G or 3G networks. The core network, as the parental part of radio network, is inevitably impacted by the re-homing in radio domain. This paper introduces the cell site re-homing in radio network and analyzes its impact on the performance of GSM/UMTS core network. The possible re-homing models are created and analyzed for core networks. The paper concludes that appropriate re-homing in radio domain, using correct algorithms, not only optimizes the radio network but also helps improve the QoS of the core network and saves the carriers' OPEX and CAPEX on their core networks.

  17. A NEW RECIPE FOR OBTAINING CENTRAL VOLUME DENSITIES OF PRESTELLAR CORES FROM SIZE MEASUREMENTS

    SciTech Connect (OSTI)

    Tassis, Konstantinos; Yorke, Harold W. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

    2011-07-10

    We propose a simple analytical method for estimating the central volume density of prestellar molecular cloud cores from their column density profiles. Prestellar cores feature a flat central part of the column density and volume density profiles of the same size indicating the existence of a uniform-density inner region. The size of this region is set by the thermal pressure force which depends only on the central volume density and temperature of the core, and can provide a direct measurement of the central volume density. Thus, a simple length measurement can immediately yield a central density estimate independent of any dynamical model for the core and without the need for fitting. Using the radius at which the column density is 90% of the central value as an estimate of the size of the flat inner part of the column density profile yields an estimate of the central volume density within a factor of two for well-resolved cores.

  18. Modeling probability distributions with predictive state representations

    E-Print Network [OSTI]

    Wiewiora, Eric Walter

    2008-01-01

    Discovery is the process of choosing the core tests, whose success probabilities will become the state of the learned model.

  19. Larger foraminifer biostratigraphy of PEACE boreholes, Enewetak Atoll, Western Pacific Ocean. Geologic and geophysical investigations of Enewetak Atoll, Republic of the Marshall Islands. Professional paper

    SciTech Connect (OSTI)

    Gibson, T.G.; Margerum, R.

    1991-01-01

    Larger foraminiferal assemblages, including Lepidocyclina orientalis, Miogypsina thecideaeformis, Miogypsinoides dehaartii, etc., and a smaller foraminifer, Austrotrillina striata, are used to correlate upper Oligocene and lower Miocene strata in the Pacific Atoll Exploration Program (PEACE) boreholes at Enewetak Atoll, Republic of the Marshall Islands, western Pacific Ocean, with the Te and Tf zones of the previously established Tertiary Far East Letter Zonation. Correlation using these two benthic groups is critical because calcareous nannofossils and planktic foraminifers are absent in the lower Miocene strata. Biostratigraphic data from these boreholes delineate a thick (greater than 700 feet) sequence of upper Oligocene and lower Miocene strata corresponding to lower and upper Te zone. These strata document a major period of carbonate accumulation at Enewetak during the Late Oligocene and early Miocene (26 to 18 million years ago).

  20. A dynamically collapsing core and a precursor of a core in a filament supported by turbulent and magnetic pressures

    SciTech Connect (OSTI)

    Furuya, Ray S.; Kitamura, Yoshimi; Shinnaga, Hiroko E-mail: kitamura@isas.jaxa.jp

    2014-10-01

    To study physical properties of the natal filament gas around the cloud core harboring an exceptionally young low-mass protostar GF 9-2, we carried out J = 1-0 line observations of {sup 12}CO, {sup 13}CO, and C{sup 18}O molecules using the Nobeyama 45 m telescope. The mapping area covers ? one-fifth of the whole filament. Our {sup 13}CO and C{sup 18}O maps clearly demonstrate that the core formed at the local density maxima of the filament, and the internal motions of the filament gas are totally governed by turbulence with Mach number of ?2. We estimated the scale height of the filament to be H = 0.3-0.7 pc, yielding the central density of n {sub c} = 800-4200 cm{sup –3}. Our analysis adopting an isothermal cylinder model shows that the filament is supported by the turbulent and magnetic pressures against the radial and axial collapse due to self-gravity. Since both the dissipation timescales of the turbulence and the transverse magnetic fields can be comparable to the free-fall time of the filament gas of 10{sup 6} yr, we conclude that the local decay of the supersonic turbulence and magnetic fields made the filament gas locally unstable, hence making the core collapse. Furthermore, we newly detected a gas condensation with velocity width enhancement to ?0.3 pc southwest of the GF 9-2 core. The condensation has a radius of ?0.15 pc and an LTE mass of ?5 M {sub ?}. Its internal motion is turbulent with Mach number of ?3, suggesting a gravitationally unbound state. Considering the uncertainties in our estimates, however, we propose that the condensation is a precursor of a cloud core, which would have been produced by the collision of the two gas components identified in the filament.

  1. All Metal Iron Core For A Low Aspect Ratio Tokamak

    SciTech Connect (OSTI)

    D.A. Gates, C. Jun, I. Zatz, A. Zolfaghari

    2010-06-02

    A novel concept for incorporating a iron core transformer within a axisymmetric toroidal plasma containment device with a high neutron flux is described. This design enables conceptual design of low aspect ratio devices which employ standard transformer-driven plasma startup by using all-metal high resistance separators between the toroidal field windings. This design avoids the inherent problems of a multiturn air core transformer which will inevitably suffer from strong neutron bombardment and hence lose the integrity of its insulation, both through long term material degradation and short term neutron- induced conductivity.. A full 3-dimensional model of the concept has been developed within the MAXWELL program and the resultant loop voltage calculated. The utility of the result is found to be dependent on the resistivity of the high resistance separators. Useful loop voltage time histories have been obtained using achievable resistivities.

  2. An asteroseismic study of the beta Cephei star theta Ophiuchi: constraints on global stellar parameters and core overshooting

    E-Print Network [OSTI]

    M. Briquet; T. Morel; A. Thoul; R. Scuflaire; A. Miglio; J. Montalban; M. -A. Dupret; C. Aerts

    2007-06-22

    We present a seismic study of the beta Cephei star theta Ophiuchi. Our analysis is based on the observation of one radial mode, one rotationally split l = 1 triplet and three components of a rotationally split l = 2 quintuplet for which the m-values were well identified by spectroscopy. We identify the radial mode as fundamental, the triplet as p_1 and the quintuplet as g_1. Our NLTE abundance analysis results in a metallicity and CNO abundances in full agreement with the most recent updated solar values. With X \\in [0.71,0.7211] and Z \\in [0.009,0.015], and using the Asplund et al. (2005) mixture but with a Ne abundance about 0.3 dex larger (Cunha et al. 2006), the matching of the three independent modes, enables us to deduce constrained ranges for the mass (M = 8.2 +/- 0.3 Msun) and central hydrogen abundance (X_c = 0.38 +/- 0.02) of theta Oph and to prove the occurrence of core overshooting (alpha_ov = 0.44 +/- 0.07). We also derive an equatorial rotation velocity of 29 +/- 7 km/s. Moreover, we show that the observed non-equidistance of the l=1 triplet can be reproduced by second order effects of rotation. Finally, we show that the observed rotational splitting of two modes cannot rule out a rigid rotation model.

  3. 510 Plant Disease / Vol. 97 No. 4 Etiology of Moldy Core, Core Browning, and Core Rot of Fuji Apple in China

    E-Print Network [OSTI]

    Biggs, Alan R.

    510 Plant Disease / Vol. 97 No. 4 Etiology of Moldy Core, Core Browning, and Core Rot of Fuji Apple, and core rot of Fuji apple in China. Plant Dis. 97:510-516. `Fuji' apple fruit were collected in Shaanxi to species. Pathogenicity was determined by cutting apple fruit into halves and daubing spore suspensions

  4. OSCAR Parallelizing Compiler Cooperative Heterogeneous Multi-core Architecture

    E-Print Network [OSTI]

    Kasahara, Hironori

    OSCAR Parallelizing Compiler Cooperative Heterogeneous Multi-core Architecture Akihiro Hayashi, powerful parallelizing compiler for hetero- geneous multi-core architectures is expected. Furthermore, cooperative work between parallelizing compiler and hetero- geneous multi-core architectures is important

  5. Environmental impact of various kayak core materials

    E-Print Network [OSTI]

    Kirkland, David R. (David Roger)

    2008-01-01

    This thesis compares the environmental impact of fiberglass, Kevlar, carbon fiber, and cork. A kayak company is interested in using cork as a core material, and would like to claim that it is the most environmentally ...

  6. SF Bay Cores Uncovering Our Dirty Past

    E-Print Network [OSTI]

    FOR? #12;ABSOLUTELY SOMETHING #12;Sediments Tell Our History America's largest core? Even when) > SB, SPB, SUB · Alternative hypotheses?... #12;Old King Coal? U.S. Dept of Energy · Urban residential

  7. KSI's Cross Insulated Core Transformer Technology

    SciTech Connect (OSTI)

    Uhmeyer, Uwe [Kaiser Systems, Inc, 126 Sohier Road, Beverly, MA 01915 (United States)

    2009-08-04

    Cross Insulated Core Transformer (CCT) technology improves on Insulated Core Transformer (ICT) implementations. ICT systems are widely used in very high voltage, high power, power supply systems. In an ICT transformer ferrite core sections are insulated from their neighboring ferrite cores. Flux leakage is present at each of these insulated gaps. The flux loss is raised to the power of stages in the ICT design causing output voltage efficiency to taper off with increasing stages. KSI's CCT technology utilizes a patented technique to compensate the flux loss at each stage of an ICT system. Design equations to calculate the flux compensation capacitor value are presented. CCT provides corona free operation of the HV stack. KSI's CCT based High Voltage power supply systems offer high efficiency operation, high frequency switching, low stored energy and smaller size over comparable ICT systems.

  8. Armor systems including coated core materials

    DOE Patents [OSTI]

    Chu, Henry S. (Idaho Falls, ID); Lillo, Thomas M. (Idaho Falls, ID); McHugh, Kevin M. (Idaho Falls, ID)

    2012-07-31

    An armor system and method involves providing a core material and a stream of atomized coating material that comprises a liquid fraction and a solid fraction. An initial layer is deposited on the core material by positioning the core material in the stream of atomized coating material wherein the solid fraction of the stream of atomized coating material is less than the liquid fraction of the stream of atomized coating material on a weight basis. An outer layer is then deposited on the initial layer by positioning the core material in the stream of atomized coating material wherein the solid fraction of the stream of atomized coating material is greater than the liquid fraction of the stream of atomized coating material on a weight basis.

  9. Armor systems including coated core materials

    DOE Patents [OSTI]

    2013-10-08

    An armor system and method involves providing a core material and a stream of atomized coating material that comprises a liquid fraction and a solid fraction. An initial layer is deposited on the core material by positioning the core material in the stream of atomized coating material wherein the solid fraction of the stream of atomized coating material is less than the liquid fraction of the stream of atomized coating material on a weight basis. An outer layer is then deposited on the initial layer by positioning the core material in the stream of atomized coating material wherein the solid fraction of the stream of atomized coating material is greater than the liquid fraction of the stream of atomized coating material on a weight basis.

  10. SU-E-T-567: A Three-Field Mono-Isocentric Inverse Treatment Planning Method for the Patients with Larger Breasts

    SciTech Connect (OSTI)

    Zhang, T; Marina, O; Chen, P; Teahan, M; Liu, Q; Benedetti, L

    2014-06-01

    Purpose: The purpose of this study is to develop a three-field monoisocentric inverse breast treatment planning technique without the use of half-beam block. Methods: Conventional three-field breast treatment with supraclavicular half-beam blocked requires two isocenters when the breast is too large to be contained within half-beam. The inferior border of the supraclavicular field and superior borders of the breast fields are matched on patient's skin with the light field. This method causes a large dose variation in the matching region due to daily setup uncertainties and requires a longer treatment setup time. We developed a three-field mono-isocentric planning method for the treatment of larger breasts. The three fields share the same isocenter located in the breast. Beam matching is achieved by rotating collimator, couch and gantry. Furthermore, we employed a mixed open-IMRT inverse optimization method to improve dose uniformity and coverage. Results: Perfect geometric beam matching was achieved by rotating couch, collimator and gantry together. Treatment setup time was significantly reduced without light-field matching during treatment deliveries. Inverse mixed open-IMRT optimization method achieved better dose uniformity and PTV coverage while keeping sufficient air flash to compensate setup and breast shape changes in daily treatments. Conclusion: By eliminating light field matching, the three-field mono-isocentric treatment method can significantly reduce setup time and uncertainty for large breast patients. Plan quality is further improved by inverse IMRT planning.

  11. Uncertainties in modelling and scaling of critical flows and pump model in TRAC-PF1/MOD1

    SciTech Connect (OSTI)

    Rohatgi, U.S.; Yu, Wen-Shi

    1987-01-01

    The USNRC has established a Code Scalability, Applicability and Uncertainty (CSAU) evaluation methodology to quantify the uncertainty in the prediction of safety parameters by the best estimate codes. These codes can then be applied to evaluate the Emergency Core Cooling System (ECCS). The TRAC-PF1/MOD1 version was selected as the first code to undergo the CSAU analysis for LBLOCA applications. It was established through this methodology that break flow and pump models are among the top ranked models in the code affecting the peak clad temperature (PCT) prediction for LBLOCA. The break flow model bias or discrepancy and the uncertainty were determined by modelling the test section near the break for 12 Marviken tests. It was observed that the TRAC-PF1/MOD1 code consistently underpredicts the break flow rate and that the prediction improved with increasing pipe length (larger L/D). This is true for both subcooled and two-phase critical flows. A pump model was developed from Westinghouse (1/3 scale) data. The data represent the largest available test pump relevant to Westinghouse PWRs. It was then shown through the analysis of CE and CREARE pump data that larger pumps degrade less and also that pumps degrade less at higher pressures. Since the model developed here is based on the 1/3 scale pump and on low pressure data, it is conservative and will overpredict the degradation when applied to PWRs.

  12. Power distributions in fresh and depleted LEU and HEU cores of the MITR reactor.

    SciTech Connect (OSTI)

    Wilson, E.H.; Horelik, N.E.; Dunn, F.E.; Newton, T.H., Jr.; Hu, L.; Stevens, J.G. (Nuclear Engineering Division); (2MIT Nuclear Reactor Laboratory and Nuclear Science and Engineering Department)

    2012-04-04

    The Massachusetts Institute of Technology Reactor (MITR-II) is a research reactor in Cambridge, Massachusetts designed primarily for experiments using neutron beam and in-core irradiation facilities. It delivers a neutron flux comparable to current LWR power reactors in a compact 6 MW core using Highly Enriched Uranium (HEU) fuel. In the framework of its non-proliferation policies, the international community presently aims to minimize the amount of nuclear material available that could be used for nuclear weapons. In this geopolitical context, most research and test reactors both domestic and international have started a program of conversion to the use of Low Enriched Uranium (LEU) fuel. A new type of LEU fuel based on an alloy of uranium and molybdenum (UMo) is expected to allow the conversion of U.S. domestic high performance reactors like the MITR-II reactor. Toward this goal, core geometry and power distributions are presented. Distributions of power are calculated for LEU cores depleted with MCODE using an MCNP5 Monte Carlo model. The MCNP5 HEU and LEU MITR models were previously compared to experimental benchmark data for the MITR-II. This same model was used with a finer spatial depletion in order to generate power distributions for the LEU cores. The objective of this work is to generate and characterize a series of fresh and depleted core peak power distributions, and provide a thermal hydraulic evaluation of the geometry which should be considered for subsequent thermal hydraulic safety analyses.

  13. Formed Core Sampler Hydraulic Conductivity Testing

    SciTech Connect (OSTI)

    Miller, D. H.; Reigel, M. M.

    2012-09-25

    A full-scale formed core sampler was designed and functionally tested for use in the Saltstone Disposal Facility (SDF). Savannah River National Laboratory (SRNL) was requested to compare properties of the formed core samples and core drilled samples taken from adjacent areas in the full-scale sampler. While several physical properties were evaluated, the primary property of interest was hydraulic conductivity. Differences in hydraulic conductivity between the samples from the formed core sampler and those representing the bulk material were noted with respect to the initial handling and storage of the samples. Due to testing conditions, the site port samples were exposed to uncontrolled temperature and humidity conditions prior to testing whereas the formed core samples were kept in sealed containers with minimal exposure to an uncontrolled environment prior to testing. Based on the results of the testing, no significant differences in porosity or density were found between the formed core samples and those representing the bulk material in the test stand.

  14. Solid oxide fuel cell having monolithic core

    DOE Patents [OSTI]

    Ackerman, J.P.; Young, J.E.

    1983-10-12

    A solid oxide fuel cell is described for electrochemically combining fuel and oxidant for generating galvanic output, wherein the cell core has an array of electrolyte and interconnect walls that are substantially devoid of any composite inert materials for support. Instead, the core is monolithic, where each electrolyte wall consists of thin layers of cathode and anode materials sandwiching a thin layer of electrolyte material therebetween. The electrolyte walls are arranged and backfolded between adjacent interconnect walls operable to define a plurality of core passageways alternately arranged where the inside faces thereof have only the anode material or only the cathode material exposed. Means direct the fuel to the anode-exposed core passageways and means direct the oxidant to the anode-exposed core passageways and means direct the oxidant to the cathode-exposed core passageway; and means also direct the galvanic output to an exterior circuit. Each layer of the electrolyte and interconnect materials is of the order of 0.002 to 0.01 cm thick; and each layer of the cathode and anode materials is of the order of 0.002 to 0.05 cm thick.

  15. Hybrid Parallelism for Volume Rendering on Large, Multi- and Many-core Systems

    SciTech Connect (OSTI)

    Howison, Mark; Bethel, E. Wes; Childs, Hank

    2011-01-01

    With the computing industry trending towards multi- and many-core processors, we study how a standard visualization algorithm, ray-casting volume rendering, can benefit from a hybrid parallelism approach. Hybrid parallelism provides the best of both worlds: using distributed-memory parallelism across a large numbers of nodes increases available FLOPs and memory, while exploiting shared-memory parallelism among the cores within each node ensures that each node performs its portion of the larger calculation as efficiently as possible. We demonstrate results from weak and strong scaling studies, at levels of concurrency ranging up to 216,000, and with datasets as large as 12.2 trillion cells. The greatest benefit from hybrid parallelism lies in the communication portion of the algorithm, the dominant cost at higher levels of concurrency. We show that reducing the number of participants with a hybrid approach significantly improves performance.

  16. Porous Core-Shell Nanostructures for Catalytic Applications

    E-Print Network [OSTI]

    Ewers, Trevor David

    2012-01-01

    but the palladium cores de- composed hydrogen peroxidesynthesized. Palladium is also active for hydrogen peroxideconverted to hydrogen peroxide on the palladium core before

  17. Core Coupling in Nb-99 

    E-Print Network [OSTI]

    Bindal, P. K.; Youngblood, David H.

    1974-01-01

    go~, ) five definite & = I (P, g, and P,g, ) and two defi- nite & =3 (assumed f,~,) states are seen which ac- count for virtually all of the available 2P, ~?2P,~? and lf, g, strength. Two additional weak states are observed for which no definite... parity (no neg- ative-parity shell-model levels are available for the odd neutron), indicates positive parity for these levels. None of these levels were populated with the (d, 'He) reaction. The splitting of the negative-parity 2p, y?2p,g? and lf...

  18. Overview on Hydrate Coring, Handling and Analysis

    SciTech Connect (OSTI)

    Jon Burger; Deepak Gupta; Patrick Jacobs; John Shillinglaw

    2003-06-30

    Gas hydrates are crystalline, ice-like compounds of gas and water molecules that are formed under certain thermodynamic conditions. Hydrate deposits occur naturally within ocean sediments just below the sea floor at temperatures and pressures existing below about 500 meters water depth. Gas hydrate is also stable in conjunction with the permafrost in the Arctic. Most marine gas hydrate is formed of microbially generated gas. It binds huge amounts of methane into the sediments. Worldwide, gas hydrate is estimated to hold about 1016 kg of organic carbon in the form of methane (Kvenvolden et al., 1993). Gas hydrate is one of the fossil fuel resources that is yet untapped, but may play a major role in meeting the energy challenge of this century. In June 2002, Westport Technology Center was requested by the Department of Energy (DOE) to prepare a ''Best Practices Manual on Gas Hydrate Coring, Handling and Analysis'' under Award No. DE-FC26-02NT41327. The scope of the task was specifically targeted for coring sediments with hydrates in Alaska, the Gulf of Mexico (GOM) and from the present Ocean Drilling Program (ODP) drillship. The specific subjects under this scope were defined in 3 stages as follows: Stage 1: Collect information on coring sediments with hydrates, core handling, core preservation, sample transportation, analysis of the core, and long term preservation. Stage 2: Provide copies of the first draft to a list of experts and stakeholders designated by DOE. Stage 3: Produce a second draft of the manual with benefit of input from external review for delivery. The manual provides an overview of existing information available in the published literature and reports on coring, analysis, preservation and transport of gas hydrates for laboratory analysis as of June 2003. The manual was delivered as draft version 3 to the DOE Project Manager for distribution in July 2003. This Final Report is provided for records purposes.

  19. Managing water addition to a degraded core

    SciTech Connect (OSTI)

    Kuan, P.; Hanson, D.J. (EG and G Idaho, Inc., Idaho Falls, ID (United States)); Odar, F. (Nuclear Regulatory Commission, Washington, DC (United States))

    1991-01-01

    In this paper we present information that can be used in severe accident management by providing an improved understanding of the effects of water addition to a degraded core. This improved understanding is developed using a diagram showing a sequence of core damage states. Whenever possible, a temperature and a time after accident initiation are estimated for each damage state in the sequence diagram. This diagram can be used to anticipate the evolution of events during an accident. Possible responses of plant instruments are described to identify these damage states and the effects of water addition. The rate and amount of water addition needed (1) to remove energy from the core, (2) to stabilize the core or (3) to not adversely affect the damage progression, are estimated. Analysis of the capability to remove energy from large cohesive and particulate debris beds indicates that these beds may not be stabilized in the core region and they may partially relocate to the lower plenum of the reactor vessel.

  20. Managing water addition to a degraded core

    SciTech Connect (OSTI)

    Kuan, P.; Hanson, D.J. [EG and G Idaho, Inc., Idaho Falls, ID (United States); Odar, F. [Nuclear Regulatory Commission, Washington, DC (United States)

    1991-12-31

    In this paper we present information that can be used in severe accident management by providing an improved understanding of the effects of water addition to a degraded core. This improved understanding is developed using a diagram showing a sequence of core damage states. Whenever possible, a temperature and a time after accident initiation are estimated for each damage state in the sequence diagram. This diagram can be used to anticipate the evolution of events during an accident. Possible responses of plant instruments are described to identify these damage states and the effects of water addition. The rate and amount of water addition needed (1) to remove energy from the core, (2) to stabilize the core or (3) to not adversely affect the damage progression, are estimated. Analysis of the capability to remove energy from large cohesive and particulate debris beds indicates that these beds may not be stabilized in the core region and they may partially relocate to the lower plenum of the reactor vessel.

  1. Solid oxide fuel cell having monolithic core

    DOE Patents [OSTI]

    Ackerman, John P. (Downers Grove, IL); Young, John E. (Woodridge, IL)

    1984-01-01

    A solid oxide fuel cell for electrochemically combining fuel and oxidant for generating galvanic output, wherein the cell core has an array of electrolyte and interconnect walls that are substantially devoid of any composite inert materials for support. Instead, the core is monolithic, where each electrolyte wall consists of thin layers of cathode and anode materials sandwiching a thin layer of electrolyte material therebetween, and each interconnect wall consists of thin layers of the cathode and anode materials sandwiching a thin layer of interconnect material therebetween. The electrolyte walls are arranged and backfolded between adjacent interconnect walls operable to define a plurality of core passageways alternately arranged where the inside faces thereof have only the anode material or only the cathode material exposed. Means direct the fuel to the anode-exposed core passageways and means direct the oxidant to the cathode-exposed core passageway; and means also direct the galvanic output to an exterior circuit. Each layer of the electrolyte and interconnect materials is of the order of 0.002-0.01 cm thick; and each layer of the cathode and anode materials is of the order of 0.002-0.05 cm thick.

  2. Dark matter cores all the way down

    E-Print Network [OSTI]

    Read, J I; Collins, M L M

    2015-01-01

    We use high resolution simulations of isolated dwarf galaxies to study the physics of dark matter cusp-core transformation at the edge of galaxy formation (Mvir = 10^7 - 10^9 Msun). We work at a resolution (4 pc) at which the impact from individual supernovae explosions can be resolved, becoming insensitive to even large changes in our numerical 'sub-grid' parameters. We find that our dwarf galaxies give a remarkable match to the stellar light profile; star formation history; metallicity distribution function; and star/gas kinematics of isolated dwarf irregular galaxies. Our key result is that dark matter cores of size comparable to the half light radius r_1/2 always form if star formation proceeds for long enough. Cores fully form in less than 4 Gyrs for the Mvir =10^8 Msun and 14 Gyrs for the 10^9 Msun dwarf. We provide a convenient two parameter 'coreNFW' fitting function that captures this dark matter core growth as a function of star formation time and the projected half light radius. Our results have se...

  3. Is inner core seismic anisotropy a marker of plastic flow of cubic iron?

    E-Print Network [OSTI]

    Lincot, A; Cardin, Philippe

    2015-01-01

    This paper investigates whether observations of seismic anisotropy are compatible with a cubic structure of the inner core Fe alloy. We assume that anisotropy is the result of plastic deformation within a large scale flow induced by preferred growth at the inner core equator. Based on elastic moduli from the literature, bcc- or fcc-Fe produce seismic anisotropy well below seismic observations ($\\textless{}0.4\\%$). A Monte-Carlo approach allows us to generalize this result to any form of elastic anisotropy in a cubic system. Within our model, inner core global anisotropy is not compatible with a cubic structure of Fe alloy. Hence, if the inner core material is indeed cubic, large scale coherent anisotropic structures, incompatible with plastic deformation induced by large scale flow, must be present.

  4. The size of most massive neutron stars may reveal its exotic cores

    E-Print Network [OSTI]

    Neha Gupta; P. Arumugam

    2013-02-19

    The recent high precision observation of the most massive pulsar J1614-2230 with $(1.97\\pm0.04)$ solar mass ($M_\\odot$) was reported with a suggestion that many nuclear models which consider exotic particles in the core could be ruled out. However, many recent calculations could explain this star with various exotic particles, rendering the precise mass measurements insufficient to conclude on exotic cores. We examine the sensitivity of the radius of such a star to the details of its core. With our calculations and analysis, here we show that, for the most massive neutron star, with a precise observation of its radius it is possible to ascertain the presence of exotic cores.

  5. Neutronics Analyses of the Minimum Original HEU TREAT Core

    SciTech Connect (OSTI)

    Kontogeorgakos, D.; Connaway, H.; Yesilyurt, G.; Wright, A.

    2014-04-01

    This work was performed to support the feasibility study on the potential conversion of the Transient Reactor Test Facility (TREAT) at Idaho National Laboratory from the use of high-enriched uranium (HEU) fuel to the use of low-enriched uranium (LEU) fuel. The analyses were performed by the GTRI Reactor Conversion staff at the Argonne National Laboratory (ANL). The objective of this study was to validate the MCNP model of the TREAT reactor with the well-documented measurements which were taken during the start-up and early operation of TREAT. Furthermore, the effect of carbon graphitization was also addressed. The graphitization level was assumed to be 100% (ANL/GTRI/TM-13/4). For this purpose, a set of experiments was chosen to validate the TREAT MCNP model, involving the approach to criticality procedure, in-core neutron flux measurements with foils, and isothermal temperature coefficient and temperature distribution measurements. The results of this study extended the knowledge base for the TREAT MCNP calculations and established the credibility of the MCNP model to be used in the core conversion feasibility analysis.

  6. Framework Application for Core Edge Transport Simulation (FACETS)

    SciTech Connect (OSTI)

    Krasheninnikov, Sergei; Pigarov, Alexander

    2011-10-15

    The FACETS (Framework Application for Core-Edge Transport Simulations) project of Scientific Discovery through Advanced Computing (SciDAC) Program was aimed at providing a high-fidelity whole-tokamak modeling for the U.S. magnetic fusion energy program and ITER through coupling separate components for each of the core region, edge region, and wall, with realistic plasma particles and power sources and turbulent transport simulation. The project also aimed at developing advanced numerical algorithms, efficient implicit coupling methods, and software tools utilizing the leadership class computing facilities under Advanced Scientific Computing Research (ASCR). The FACETS project was conducted by a multi-discipline, multi-institutional teams, the Lead PI was J.R. Cary (Tech-X Corp.). In the FACETS project, the Applied Plasma Theory Group at the MAE Department of UCSD developed the Wall and Plasma-Surface Interaction (WALLPSI) module, performed its validation against experimental data, and integrated it into the developed framework. WALLPSI is a one-dimensional, coarse grained, reaction/advection/diffusion code applied to each material boundary cell in the common modeling domain for a tokamak. It incorporates an advanced model for plasma particle transport and retention in the solid matter of plasma facing components, simulation of plasma heat power load handling, calculation of erosion/deposition, and simulation of synergistic effects in strong plasma-wall coupling.

  7. The BubbleWrap Many-Core: Popping Cores for Sequential Acceleration

    E-Print Network [OSTI]

    Torrellas, Josep

    @illinois.edu http://iacoma.cs.uiuc.edu ABSTRACT Many-core scaling now faces a power wall. The gap between the number time to meet the power budget. To push back the many-core power wall, this paper proposes Dy- namic, Process Scaling, Power Wall. 1. INTRODUCTION Ideal CMOS device scaling [9] relies on scaling voltages down

  8. Chiral Symmetry Breaking in Bent-Core Liquid Crystals

    E-Print Network [OSTI]

    Lech Longa; Grzegorz Paj?k; Thomas Wydro

    2009-02-04

    By molecular modeling we demonstrate that the nematic long-range order discovered in bent-core liquid crystal systems should reveal further spatially homogeneous phases. Two of them are identified as a tetrahedratic nematic ($N_T$) phase with $D_{2d}$ symmetry and a chiral tetrahedratic nematic ($N_T^*$) phase with $D_2$ symmetry. These new phases were found for a lattice model with quadrupolar and octupolar anisotropic interactions using Mean Field theory and Monte Carlo simulations. The phase diagrams exhibit tetrahedratic ($T$), $N_T$ and $N_T^*$ phases, in addition to ordinary isotropic ($I$), uniaxial nematic ($N_U$) and biaxial nematic ($N_B$) phases. To our knowledge, this is the first molecular model with spontaneous chiral symmetry breaking in non-layered systems.

  9. Neutrino flavor transformation in core-collapse supernovae

    E-Print Network [OSTI]

    Cherry, John F.; Cherry, John F.

    2012-01-01

    in Supernovae . . . . . . . . . . . . . . . . . . . . .Collapse Supernovae . . . . . . . . . . . . . . . . . . . .Mechanisms of Core-Collapse Supernovae: Simulation Results

  10. Research Cores Handbook University of Virginia School of Medicine

    E-Print Network [OSTI]

    Lawrence, Deborah

    Research Cores Handbook University of Virginia School of Medicine Office of Research Core Administration May 2013 #12;#12;Dear Colleague: Thank you for your interest in the UVA School of Medicine Shared Research Resources. Each School of Medicine Core, administered by the Office of Research Core

  11. Analytical Chemistry Core Capability Assessment - Preliminary Report

    SciTech Connect (OSTI)

    Barr, Mary E. [Los Alamos National Laboratory; Farish, Thomas J. [Los Alamos National Laboratory

    2012-05-16

    The concept of 'core capability' can be nebulous one. Even at a fairly specific level, where core capability equals maintaining essential services, it is highly dependent upon the perspective of the requestor. Samples are submitted to analytical services because the requesters do not have the capability to conduct adequate analyses themselves. Some requests are for general chemical information in support of R and D, process control, or process improvement. Many analyses, however, are part of a product certification package and must comply with higher-level customer quality assurance requirements. So which services are essential to that customer - just those for product certification? Does the customer also (indirectly) need services that support process control and improvement? And what is the timeframe? Capability is often expressed in terms of the currently utilized procedures, and most programmatic customers can only plan a few years out, at best. But should core capability consider the long term where new technologies, aging facilities, and personnel replacements must be considered? These questions, and a multitude of others, explain why attempts to gain long-term consensus on the definition of core capability have consistently failed. This preliminary report will not try to define core capability for any specific program or set of programs. Instead, it will try to address the underlying concerns that drive the desire to determine core capability. Essentially, programmatic customers want to be able to call upon analytical chemistry services to provide all the assays they need, and they don't want to pay for analytical chemistry services they don't currently use (or use infrequently). This report will focus on explaining how the current analytical capabilities and methods evolved to serve a variety of needs with a focus on why some analytes have multiple analytical techniques, and what determines the infrastructure for these analyses. This information will be useful in defining a roadmap for what future capability needs to look like.

  12. Large enhanced dielectric permittivity in polyaniline passivated core-shell nano magnetic iron oxide by plasma polymerization

    SciTech Connect (OSTI)

    Joy, Lija K.; Sooraj, V.; Sethulakshmi, N.; Anantharaman, M. R., E-mail: mraiyer@yahoo.com [Department of Physics, Cochin University of Science and Technology, Cochin-682022, Kerala (India); Sajeev, U. S. [Department of Physics, Government College, Kottayam-686613, Kerala (India); Nair, Swapna S. [Department of Physics, School of Mathematical and Physical Sciences, Central University of Kerala, Kasargode-671123, Kerala (India); Narayanan, T. N. [CSIR-Central Electrochemical Research Institute, Karaikkudi-630006, Tamil Nadu (India); Ajayan, P. M. [Department of Material Science and Nano Engineering, Rice University, 6100 Main Street, Houston, Texas 7700 (United States)

    2014-03-24

    Commercial samples of Magnetite with size ranging from 25–30?nm were coated with polyaniline by using radio frequency plasma polymerization to achieve a core shell structure of magnetic nanoparticle (core)–Polyaniline (shell). High resolution transmission electron microscopy images confirm the core shell architecture of polyaniline coated iron oxide. The dielectric properties of the material were studied before and after plasma treatment. The polymer coated magnetite particles exhibited a large dielectric permittivity with respect to uncoated samples. The dielectric behavior was modeled using a Maxwell–Wagner capacitor model. A plausible mechanism for the enhancement of dielectric permittivity is proposed.

  13. Thermal metastabilities in the solar core

    E-Print Network [OSTI]

    Attila Grandpierre; Gabor Agoston

    2002-01-18

    Linear stability analysis indicates that solar core is thermally stable for infinitesimal internal perturbations. For the first time, thermal metastabilities are found in the solar core when outer perturbations with significant amplitude are present. The obtained results show that hot bubbles generated by outer perturbations may travel a significant distance in the body of the Sun. These deep-origin hot bubbles have mass, energy, and chemical composition that may be related to solar flares. The results obtained may have remarkable relations to activity cycles in planets like Jupiter and also in extrasolar planetary systems.

  14. Carolina Core Requirements The Carolina Core curriculum provides the common core of knowledge, skill, and academic experience for all Carolina

    E-Print Network [OSTI]

    Almor, Amit

    , manage and evaluate information using technology, and communicate findings. 0-3 VSR Values, Ethics selected Core learning outcomes are integrated into disciplinespecific study. For more information go 28-34 hours CMW Effective, Engaged, and Persuasive Communication: Written Component Identify

  15. Axion dark matter, solitons, and the cusp-core problem

    E-Print Network [OSTI]

    David J. E. Marsh; Ana-Roxana Pop

    2015-06-17

    Self-gravitating bosonic fields can support stable and localised field configurations. For real fields, these solutions oscillate in time and are known as oscillatons. The density profile is static, and is soliton. Such solitons should be ubiquitous in models of axion dark matter, with the soliton characteristic mass and size depending on some inverse power of the axion mass. Stable configurations of non-relativistic axions are studied numerically using the Schr\\"{o}dinger-Poisson system. This method, and the resulting soliton density profiles, are reviewed. Using a scaling symmetry and the uncertainty principle, the core size of the soliton can be related to the central density and axion mass, $m_a$, in a universal way. Solitons have a constant central density due to pressure-support, unlike the cuspy profile of cold dark matter (CDM). One consequence of this fact is that solitons composed of ultra-light axions (ULAs) may resolve the `cusp-core' problem of CDM. In DM halos, thermodynamics will lead to a CDM-like Navarro-Frenk-White profile at large radii, with a central soliton core at small radii. Using Monte-Carlo techniques to explore the possible density profiles of this form, a fit to stellar-kinematical data of dwarf spheroidal galaxies is performed. In order for ULAs to resolve the cusp-core problem (without recourse to baryon feedback or other astrophysical effects) the axion mass must satisfy $m_a<1.1\\times 10^{-22}\\text{ eV}$ at 95\\% C.L. On the other hand, ULAs with $m_a\\lesssim 1\\times 10^{-22}\\text{ eV}$ are in some tension with cosmological structure formation. An axion solution to the cusp-core problem thus makes novel predictions for future measurements of the epoch of reionisation. On the other hand, this can be seen as evidence that structure formation could soon impose a \\emph{Catch 22} on axion/scalar field DM, similar to the case of warm DM.

  16. NON-EQUILIBRIUM CHEMISTRY OF DYNAMICALLY EVOLVING PRESTELLAR CORES. II. IONIZATION AND MAGNETIC FIELD

    SciTech Connect (OSTI)

    Tassis, Konstantinos; Willacy, Karen; Yorke, Harold W.; Turner, Neal J. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

    2012-07-20

    We study the effect that non-equilibrium chemistry in dynamical models of collapsing molecular cloud cores has on measurements of the magnetic field in these cores, the degree of ionization, and the mean molecular weight of ions. We find that OH and CN, usually used in Zeeman observations of the line-of-sight magnetic field, have an abundance that decreases toward the center of the core much faster than the density increases. As a result, Zeeman observations tend to sample the outer layers of the core and consistently underestimate the core magnetic field. The degree of ionization follows a complicated dependence on the number density at central densities up to 10{sup 5} cm{sup -3} for magnetic models and 10{sup 6} cm{sup -3} in non-magnetic models. At higher central densities, the scaling approaches a power law with a slope of -0.6 and a normalization which depends on the cosmic-ray ionization rate {zeta} and the temperature T as ({zeta}T){sup 1/2}. The mean molecular weight of ions is systematically lower than the usually assumed value of 20-30, and, at high densities, approaches a value of 3 due to the asymptotic dominance of the H{sup +}{sub 3} ion. This significantly lower value implies that ambipolar diffusion operates faster.

  17. UW-Milwaukee Strategic Planning Core Team

    E-Print Network [OSTI]

    Saldin, Dilano

    UW-Milwaukee Strategic Planning Core Team Minutes Tuesday, December 18, 2012 Regents Room, Chapman" because there will be further wordsmithing when governance groups weigh in later. 3. Strategic Planning Schematic (attached) Strategic planning and action time line was disseminated to team Explained

  18. PRELIMINARY TIME ESTIMATES FOR CORING OPERATIONS

    E-Print Network [OSTI]

    PRELIMINARY TIME ESTIMATES FOR CORING OPERATIONS Ocean Drilling Program Texas A&M University portion requires the written consent of the Director, Ocean Drilling Program, Texas A&M University, College Station, Texas 77843-3469, as well as appropriate acknowledgment of this source. Technical Note 1

  19. Magnetic Fields in Quasar Cores II

    E-Print Network [OSTI]

    G. B. Taylor

    1999-11-22

    Multi-frequency polarimetry with the Very Long Baseline Array (VLBA) telescope has revealed absolute Faraday Rotation Measures (RMs) in excess of 1000 rad/m/m in the central regions of 7 out of 8 strong quasars studied (e.g., 3C 273, 3C 279, 3C 395). Beyond a projected distance of ~20 pc, however, the jets are found to have |RM| < 100 rad/m/m. Such sharp RM gradients cannot be produced by cluster or galactic-scale magnetic fields, but rather must be the result of magnetic fields organized over the central 1-100 pc. The RMs of the sources studied to date and the polarization properties of BL Lacs, quasars and galaxies are shown to be consistent so far with the predictions of unified schemes. The direct detection of high RMs in these quasar cores can explain the low fractional core polarizations usually observed in quasars at centimeter wavelengths as the result of irregularities in the Faraday screen on scales smaller than the telescope beam. Variability in the RM of the core is reported for 3C 279 between observations taken 1.5 years apart, indicating that the Faraday screen changes on that timescale, or that the projected superluminal motion of the inner jet components samples a new location in the screen with time. Either way, these changes in the Faraday screen may explain the dramatic variability in core polarization properties displayed by quasars.

  20. Detectability of deuterated water in prestellar cores

    E-Print Network [OSTI]

    Quénard, David; Vastel, Charlotte; Caselli, Paola; Ceccarelli, Cecilia

    2015-01-01

    Water is an important molecule in the chemical and thermal balance of dense molecular gas, but knowing its history through-out the various stages of the star formation is a fundamental problem. Its molecular deuteration provides us with a crucial clue to its formation history. H$_2$O has recently been detected for the first time towards the prestellar core L1544 with the Herschel Space Observatory with a high spectral resolution (HIFI instrument). Prestellar cores provide the original reservoir of material from which future planetary systems are built, but few observational constraints exist on the formation of water and none on its deuteration before the collapse starts and a protostar forms at the centre. We report on new APEX observations of the ground state 1$_{0,1}$-0$_{0,0}$ HDO transition at 464 GHz towards the prestellar core L1544. The line is undetected, and we present an extensive study of the conditions for its detectability in cold and dense cloud cores. The water and deuterated water abundances ...

  1. Interactive Termination Proofs using Termination Cores

    E-Print Network [OSTI]

    Manolios, Panagiotis "Pete"

    Interactive Termination Proofs using Termination Cores Panagiotis Manolios and Daron Vroon College@ccs.neu.edu, daron.vroon@gmail.com Abstract. Recent advances in termination analysis have yielded new methods and determining how to proceed. In this paper, we address the issue of building termination analysis engines

  2. Core Networks: Part III Ferhat Dikbiyik

    E-Print Network [OSTI]

    California at Davis, University of

    Review: Core Networks Part III by F. Dikbiyik Session Code Session Title Industry Academia NMC Flexible Session Code Session Title Industry Academia OMW Optical Network Demos OTuI Spectrally Efficient-way optical wavelength multicasting was experimentally demonstrated based on the dual-pump FWM process in HNLF

  3. Were Moving to Phoenix Core Content

    E-Print Network [OSTI]

    Kessler, Bruce

    WeÕre Moving to Phoenix Core Content 2.2 Life Science Diversity and Adaptations of Organisms good friend just told you that his family is moving to Phoenix, Arizona from Kentucky. Your friend. You need to find out if the same is true of Phoenix, Arizona. Preassessment 1. What kinds of plant

  4. In-core and ex-core calculations of the VENUS simulated PWR benchmark experiment

    SciTech Connect (OSTI)

    Williams, M.L.; Chowdhury, P.; Landesman, M.; Kam, F.B.K.

    1985-01-01

    The VENUS PWR engineering mockup experiment was established to simulate a beginning-of-life, generic PWR configuration at the zero-power VENUS critical facility located at CEN/SCK, Mol, Belgium. The experimental measurement program consists of (1) gamma scans to determine the core power distribution, (2) in-core and ex-core foil activations, (3) neutron spectrometer measurements, and (4) gamma heating measurements with TLD's. Analysis of the VENUS benchmark has been performed with two-dimensional discrete ordinates transport theory, using the DOT-IV code.

  5. Results of Reactor Materials Experiments Investigating 2-D Core-Concrete Interaction and Debris Coolability

    SciTech Connect (OSTI)

    Farmer, M. T.; Lomperski, S. [Nuclear Engineering Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL 60439 (United States); Basu, S. [U.S. Nuclear Regulatory Commission, MS-T10K8, 11545 Rockville Pike, Rockville, MD 20852 (United States)

    2004-07-01

    The OECD-sponsored Melt Coolability and Concrete Interaction (MCCI) program is conducting reactor materials experiments and associated analysis to achieve the following objectives: 1) resolution of the ex-vessel debris coolability issue, and 2) address remaining uncertainties related to long-term two-dimensional molten core-concrete interactions under both wet and dry cavity conditions. Achievement of these two objectives will demonstrate the efficacy of severe accident management guidelines for existing plants and provide the technical basis for better containment designs of future plants. With respect to the second objective, there remain uncertainties in the models that evaluate the lateral vs. axial power split during core-concrete interaction because of a lack of truly two-dimensional experiment data. As a first step in bridging this gap, a large scale Core-Concrete Interaction experiment (CCI-1) has been conducted as part of the MCCI program. This test investigated the interaction of a 400 kg core-oxide melt with a crucible made of siliceous concrete along two walls and the base. The two remaining walls were made of non-ablative magnesium oxide. The initial phase of the test was conducted under dry conditions. After a predefined ablation depth was achieved, the cavity was flooded to obtain data on the coolability of a core melt after core-concrete interaction has progressed for some time. This paper provides a description of the test facility and an overview of results from this test. (authors)

  6. Carbon-Supported IrNi Core-Shell Nanoparticles: Synthesis Characterization and Catalytic Activity

    SciTech Connect (OSTI)

    K Sasaki; K Kuttiyiel; L Barrio; D Su; A Frenkel; N Marinkovic; D Mahajan; R Adzic

    2011-12-31

    We synthesized carbon-supported IrNi core-shell nanoparticles by chemical reduction and subsequent thermal annealing in H{sub 2}, and verified the formation of Ir shells on IrNi solid solution alloy cores by various experimental methods. The EXAFS analysis is consistent with the model wherein the IrNi nanoparticles are composed of two-layer Ir shells and IrNi alloy cores. In situ XAS revealed that the Ir shells completely protect Ni atoms in the cores from oxidation or dissolution in an acid electrolyte under elevated potentials. The formation of Ir shell during annealing due to thermal segregation is monitored by time-resolved synchrotron XRD measurements, coupled with Rietveld refinement analyses. The H{sub 2} oxidation activity of the IrNi nanoparticles was found to be higher than that of a commercial Pt/C catalyst. This is predominantly due to Ni-core-induced Ir shell contraction that makes the surface less reactive for IrOH formation, and the resulting more metallic Ir surface becomes more active for H{sub 2} oxidation. This new class of core-shell nanoparticles appears promising for application as hydrogen anode fuel cell electrocatalysts.

  7. Improved dye sensitized solar cell performance in larger cell size by using TiO This article has been downloaded from IOPscience. Please scroll down to see the full text article.

    E-Print Network [OSTI]

    Siegel, Paul H.

    Improved dye sensitized solar cell performance in larger cell size by using TiO 2 nanotubes.1088/0957-4484/24/4/045401 Improved dye sensitized solar cell performance in larger cell size by using TiO2 nanotubes Yanyan Zhang1 the use of anodized TiO2 nanotubes on Ti foil in combination with the standard TiO2 nanoparticle paste

  8. The Origin of Blue Cores in Hubble Deep Fields E/S0 galaxies

    E-Print Network [OSTI]

    Felipe Menanteau; Raul Jimenez; Francesca Matteucci

    2001-09-29

    In this letter we address the problem of the origin of blue cores and inverse color gradients in early-type galaxies reported in the Hubble Deep Field North and South (HDFs) by Menanteau, Abraham & Ellis 2001. We use a multi-zone single collapse model. This model accounts for the observed blue cores by adopting a broad spread in formation redshifts for ellipticals, allowing some of these galaxies begin forming no more than ~1 Gyr before the redshift of observation. The single-zone collapse model then produces cores that are bluer than the outer regions because of the increase of the local potential well toward the center which makes star-formation more extended in the central region of the galaxy. We compare the predicted V-I(r) color gradients with the observed ones using the redshift of formation ($z_F$) of the elliptical as the only free parameter. We find that the model can account with relatively good agreement for the blue cores and inverse color gradients found in many spheroidals and at the same time for the red and smooth colors profiles reported. Based on the model our analysis suggests two populations of field ellipticals, one formed recently, within $\\lesssim1$Gyr and another much older formed $\\gtrsim4$Gyr since the redshift of observation.

  9. Studies of 3D-cloud optical depth from small to very large values, and of the radiation and remote sensing impacts of larger-drop clustering

    SciTech Connect (OSTI)

    2007-05-04

    We have basically completed all the goals stated in the previous proposal and published or submitted journal papers thereon, the only exception being First-Principles Monte Carlo which has taken more time than expected. We finally finished the comprehensive book on 3D cloud radiative transfer (edited by Marshak and Davis and published by Springer), with many contributions by ARM scientists; this book was highlighted in the 2005 ARM Annual Report. We have also completed (for now) our pioneering work on new models of cloud drop clustering based on ARM aircraft FSSP data, with applications both to radiative transfer and to rainfall. This clustering work was highlighted in the FY07 “Our Changing Planet” (annual report of the US Climate Change Science Program). Our group published 22 papers, one book, and 5 chapters in that book, during this proposal period. All are listed at the end of this section. Below, we give brief highlights of some of those papers.

  10. Gravitational Radiation from Standing Accretion Shock Instability in Core-Collapse Supernovae

    E-Print Network [OSTI]

    Kei Kotake; Naofumi Ohnishi; Shoichi Yamada

    2006-09-22

    We present the results of numerical experiments, in which we study how the asphericities induced by the growth of the standing accretion shock instability (SASI) produce the gravitational waveforms in the postbounce phase of core-collapse supernovae. To obtain the neutrino-driven explosions, we parameterize the neutrino fluxes emitted from the central protoneutron star and approximate the neutrino transfer by a light-bulb scheme. We find that the waveforms due to the anisotropic neutrino emissions show the monotonic increase with time, whose amplitudes are up to two order-of-magnitudes larger than the ones from the convective matter motions outside the protoneutron stars. We point out that the amplitudes begin to become larger when the growth of the SASI enters the nonlinear phase, in which the deformation of the shocks and the neutrino anisotropy become large. From the spectrum analysis of the waveforms, we find that the amplitudes from the neutrinos are dominant over the ones from the matter motions at the frequency below $\\sim 100$ Hz, which are suggested to be within the detection limits of the detectors in the next generation such as LCGT and the advanced LIGO for a supernova at 10 kpc. As a contribution to the gravitational wave background, we show that the amplitudes from this source could be larger at the frequency above $\\sim$ 1 Hz than the primordial gravitational wave backgrounds, but unfortunately, invisible to the proposed space-based detectors.

  11. Multitransitional observations of the CS core of L673

    E-Print Network [OSTI]

    O. Morata; J. M. Girart; R. Estalella

    2002-10-03

    A multitransitional study with the BIMA interferometric array was carried out toward the starless core found in the L673 region, in order to study the small-size structure of the cores detected with previous single--dish observations, which provides us with a test of the predictions of the chemical model of Taylor et al. (1996; 1998). We detected emission in the CS (2-1), N2H+ (1-0), and HCO+ (1-0) lines. Several clumps of size ~0.08 pc were found for each line distributed all over the region where previous single-dish emission was found (Morata et al. 1997). Each molecular transition traces differently the clump distribution, although in some cases the detected clumps are coincident. The distribution of the N2H+ emission and the single-dish NH3 emission are coincident and compatible with an origin in the same gas. The large fraction of missing flux measured for the CS (2-1) transition can be explained if the cloud is formed by a clumpy and heterogeneous medium. Four positions were selected to derive the abundance ratios [N2H+/CS] and [HCO+/CS] from the molecular column density determinations, and to compare them with the values predicted by the chemical model. The model was able to explain the interferometric observations, and, in particular, the chemical differentiation of the detected clumps and the coincidence of the NH3 and N2H+ emissions. The lack of HCO+ towards the two selected positions that trace the more evolved clumps cannot be accounted for by the model, but it is possibly due to strong self-absorption. We propose a classification of the studied clumps according to the stage of chemical evolution indicated by the molecular abundances.

  12. CT Scans of Cores Metadata, Barrow, Alaska 2015

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

    Katie McKnight; Tim Kneafsey; Craig Ulrich

    2015-03-11

    Individual ice cores were collected from Barrow Environmental Observatory in Barrow, Alaska, throughout 2013 and 2014. Cores were drilled along different transects to sample polygonal features (i.e. the trough, center and rim of high, transitional and low center polygons). Most cores were drilled around 1 meter in depth and a few deep cores were drilled around 3 meters in depth. Three-dimensional images of the frozen cores were constructed using a medical X-ray computed tomography (CT) scanner. TIFF files can be uploaded to ImageJ (an open-source imaging software) to examine soil structure and densities within each core.

  13. CT Scans of Cores Metadata, Barrow, Alaska 2015

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

    Katie McKnight; Tim Kneafsey; Craig Ulrich

    Individual ice cores were collected from Barrow Environmental Observatory in Barrow, Alaska, throughout 2013 and 2014. Cores were drilled along different transects to sample polygonal features (i.e. the trough, center and rim of high, transitional and low center polygons). Most cores were drilled around 1 meter in depth and a few deep cores were drilled around 3 meters in depth. Three-dimensional images of the frozen cores were constructed using a medical X-ray computed tomography (CT) scanner. TIFF files can be uploaded to ImageJ (an open-source imaging software) to examine soil structure and densities within each core.

  14. Validation of HELIOS for ATR Core Follow Analyses

    SciTech Connect (OSTI)

    Bays, Samuel E.; Swain, Emily T.; Crawford, Douglas S.; Nigg, David W.

    2015-03-01

    This work summarizes the validation analyses for the HELIOS code to support core design and safety assurance calculations of the Advanced Test Reactor (ATR). Past and current core safety assurance is performed by the PDQ-7 diffusion code; a state of the art reactor physics simulation tool from the nuclear industry’s earlier days. Over the past twenty years, improvements in computational speed have enabled the use of modern neutron transport methodologies to replace the role of diffusion theory for simulation of complex systems, such as the ATR. More exact methodologies have enabled a paradigm-shift away from highly tuned codes that force compliance with a bounding safety envelope, and towards codes regularly validated against routine measurements. To validate HELIOS, the 16 ATR operational cycles from late-2009 to present were modeled. The computed power distribution was compared against data collected by the ATR’s on-line power surveillance system. It was found that the ATR’s lobe-powers could be determined with ±10% accuracy. Also, the ATR’s cold startup shim configuration for each of these 16 cycles was estimated and compared against the reported critical position from the reactor log-book. HELIOS successfully predicted criticality within the tolerance set by the ATR startup procedure for 13 out of the 16 cycles. This is compared to 12 times for PDQ (without empirical adjustment). These findings, as well as other insights discussed in this report, suggest that HELIOS is highly suited for replacing PDQ for core safety assurance of the ATR. Furthermore, a modern verification and validation framework has been established that allows reactor and fuel performance data to be computed with a known degree of accuracy and stated uncertainty.

  15. Analysis of core samples from the BPXA-DOE-USGS Mount Elbert gas hydrate stratigraphic test well: Insights into core disturbance and handling

    E-Print Network [OSTI]

    Kneafsey, Timothy J.

    2010-01-01

    Mount Elbert Well) during drilling and coring operationsWell in February 2007. Coring was performed while using a custom oil-based drillingWell, pressure coring was not used, thus the core was depressurized upon ascent. Drilling

  16. Use of Solid Hydride Fuel for Improved long-Life LWR Core Designs

    SciTech Connect (OSTI)

    Greenspan, E

    2006-04-30

    The primary objective of this project was to assess the feasibility of improving the performance of PWR and BWR cores by using solid hydride fuels instead of the commonly used oxide fuel. The primary measure of performance considered is the bus-bar cost of electricity (COE). Additional performance measures considered are safety, fuel bundle design simplicity – in particular for BWR’s, and plutonium incineration capability. It was found that hydride fuel can safely operate in PWR’s and BWR’s without restricting the linear heat generation rate of these reactors relative to that attainable with oxide fuel. A couple of promising applications of hydride fuel in PWR’s and BWR’s were identified: (1) Eliminating dedicated water moderator volumes in BWR cores thus enabling to significantly increase the cooled fuel rods surface area as well as the coolant flow cross section area in a given volume fuel bundle while significantly reducing the heterogeneity of BWR fuel bundles thus achieving flatter pin-by-pin power distribution. The net result is a possibility to significantly increase the core power density – on the order of 30% and, possibly, more, while greatly simplifying the fuel bundle design. Implementation of the above modifications is, though, not straightforward; it requires a design of completely different control system that could probably be implemented only in newly designed plants. It also requires increasing the coolant pressure drop across the core. (2) Recycling plutonium in PWR’s more effectively than is possible with oxide fuel by virtue of a couple of unique features of hydride fuel – reduced inventory of U-238 and increased inventory of hydrogen. As a result, the hydride fuelled core achieves nearly double the average discharge burnup and the fraction of the loaded Pu it incinerates in one pass is double that of the MOX fuel. The fissile fraction of the Pu in the discharged hydride fuel is only ~2/3 that of the MOX fuel and the discharged hydride fuel is more proliferation resistant. Preliminary feasibility assessment indicates that by replacing some of the ZrH1.6 by ThH2 it will be possible to further improve the plutonium incineration capability of PWR’s. Other possibly promising applications of hydride fuel were identified but not evaluated in this work. A number of promising oxide fueled PWR core designs were also found as spin-offs of this study: (1) The optimal oxide fueled PWR core design features smaller fuel rod diameter of D=6.5 mm and a larger pitch-to-diameter ratio of P/D=1.39 than presently practiced by industry – 9.5mm and 1.326. This optimal design can provide a 30% increase in the power density and a 24% reduction in the cost of electricity (COE) provided the PWR could be designed to have the coolant pressure drop across the core increased from the reference 29 psia to 60 psia. (2) Using wire wrapped oxide fuel rods in hexagonal fuel assemblies it is possible to design PWR cores to operate at 54% higher power density than the reference PWR design that uses grid spacers and a square lattice, provided 60 psia coolant pressure drop across the core could be accommodated. Uprating existing PWR’s to use such cores could result in 40% reduction in the COE. The optimal lattice geometry is D = 8.08 mm and P/D = 1.41. The most notable advantages of wire wraps over grid spacers are their significant lower pressure drop, higher critical heat flux and improved vibrations characteristics.

  17. MOX fuel arrangement for nuclear core

    DOE Patents [OSTI]

    Kantrowitz, M.L.; Rosenstein, R.G.

    1998-10-13

    In order to use up a stockpile of weapons-grade plutonium, the plutonium is converted into a mixed oxide (MOX) fuel form wherein it can be disposed in a plurality of different fuel assembly types. Depending on the equilibrium cycle that is required, a predetermined number of one or more of the fuel assembly types are selected and arranged in the core of the reactor in accordance with a selected loading schedule. Each of the fuel assemblies is designed to produce different combustion characteristics whereby the appropriate selection and disposition in the core enables the resulting equilibrium cycle to closely resemble that which is produced using urania fuel. The arrangement of the MOX rods and burnable absorber rods within each of the fuel assemblies, in combination with a selective control of the amount of plutonium which is contained in each of the MOX rods, is used to tailor the combustion characteristics of the assembly. 38 figs.

  18. MOX fuel arrangement for nuclear core

    DOE Patents [OSTI]

    Kantrowitz, Mark L. (Portland, CT); Rosenstein, Richard G. (Windsor, CT)

    2001-07-17

    In order to use up a stockpile of weapons-grade plutonium, the plutonium is converted into a mixed oxide (MOX) fuel form wherein it can be disposed in a plurality of different fuel assembly types. Depending on the equilibrium cycle that is required, a predetermined number of one or more of the fuel assembly types are selected and arranged in the core of the reactor in accordance with a selected loading schedule. Each of the fuel assemblies is designed to produce different combustion characteristics whereby the appropriate selection and disposition in the core enables the resulting equilibrium cycle to closely resemble that which is produced using urania fuel. The arrangement of the MOX rods and burnable absorber rods within each of the fuel assemblies, in combination with a selective control of the amount of plutonium which is contained in each of the MOX rods, is used to tailor the combustion characteristics of the assembly.

  19. MOX fuel arrangement for nuclear core

    DOE Patents [OSTI]

    Kantrowitz, Mark L. (Portland, CT); Rosenstein, Richard G. (Windsor, CT)

    1998-01-01

    In order to use up a stockpile of weapons-grade plutonium, the plutonium is converted into a mixed oxide (MOX) fuel form wherein it can be disposed in a plurality of different fuel assembly types. Depending on the equilibrium cycle that is required, a predetermined number of one or more of the fuel assembly types are selected and arranged in the core of the reactor in accordance with a selected loading schedule. Each of the fuel assemblies is designed to produce different combustion characteristics whereby the appropriate selection and disposition in the core enables the resulting equilibrium cycle to closely resemble that which is produced using urania fuel. The arrangement of the MOX rods and burnable absorber rods within each of the fuel assemblies, in combination with a selective control of the amount of plutonium which is contained in each of the MOX rods, is used to tailor the combustion characteristics of the assembly.

  20. Mox fuel arrangement for nuclear core

    DOE Patents [OSTI]

    Kantrowitz, Mark L. (Portland, CT); Rosenstein, Richard G. (Windsor, CT)

    2001-05-15

    In order to use up a stockpile of weapons-grade plutonium, the plutonium is converted into a mixed oxide (MOX) fuel form wherein it can be disposed in a plurality of different fuel assembly types. Depending on the equilibrium cycle that is required, a predetermined number of one or more of the fuel assembly types are selected and arranged in the core of the reactor in accordance with a selected loading schedule. Each of the fuel assemblies is designed to produce different combustion characteristics whereby the appropriate selection and disposition in the core enables the resulting equilibrium cycle to closely resemble that which is produced using urania fuel. The arrangement of the MOX rods and burnable absorber rods within each of the fuel assemblies, in combination with a selective control of the amount of plutonium which is contained in each of the MOX rods, is used to tailor the combustion. characteristics of the assembly.

  1. Designing a New Fuel for HFIR-Performance Parameters for LEU Core Configurations

    SciTech Connect (OSTI)

    Ilas, Germina [ORNL; Primm, Trent [ORNL; Gehin, Jess C [ORNL

    2009-01-01

    An engineering design study for a fuel that would enable the conversion of the High Flux Isotope Reactor from highly enriched uranium to low enriched uranium fuel is ongoing as part of an effort sponsored by the U.S. Department of Energy's National Nuclear Security Administration through the Global Threat Reduction Initiative. Given the unique fuel and core design and high power density of the reactor and the requirement that the impact of the fuel change on the core performance and operation be minimal, this conversion study presents a complex and challenging task, requiring improvements in the computational models currently used to support the operation of the reactor and development of new models that would take advantage of newly available simulation methods and tools. The computational models used to search for a fuel design that would meet the requirements for the conversion study and the results obtained with these models are presented and discussed. Estimates of relevant reactor performance parameters for the low enriched uranium fuel core are presented and compared to the corresponding data for the currently operating highly enriched uranium fuel core.

  2. Thomson scattering for core plasma on DEMO

    SciTech Connect (OSTI)

    Mukhin, E. E.; Kurskiev, G. S.; Tolstyakov, S. Yu.; Bukreev, I. M.; Chernakov, P. V.; Kochergin, M. M.; Koval, A. N.; Litvinov, A. E.; Masyukevich, S. V.; Razdobarin, A. G.; Semenov, V. V. [Ioffe Physical Technical Institute, 26 Polytechnicheskaya St., St. Petersburg (Russian Federation); Kukushkin, A. B.; Sdvizhenskii, P. A. [NRC Kurchatov Institute, 1, Akademika Kurchatova pl., Moscow, 123182 (Russian Federation); Andrew, P. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul Lez Durance (France)

    2014-08-21

    This paper describes the challenges of Thomson scattering implementation for core plasma on DEMO and evaluates the capability to measure extremely high electron temperature range 0.5-40keV. A number of solutions to be developed for ITER diagnostics are suggested in consideration of their realization for DEMO. New approaches suggested for DEMO may also be of interest to ITER and currently operating magnetic confinement devices.

  3. DOE GIS core team - a best practice

    SciTech Connect (OSTI)

    Bollinger, J.; Bhaduri, Budhendra; Bleakly, D. R.; Brady-Sabeff, Liz; Guber, Al; Guziel, K. A.; Hargrove, Susan; Lee, J.; Lee, R.; Mickus, Kurt; Morehouse, David; Moore, K.; Ramsdell, Amy; Rich, P. M.

    2004-01-01

    Large government organizations such as the Department of Energy (DOE) are challenged with identifying and implementing best geospatial information management practices to ensure that operational needs are met and government objectives are achieved. Geographic Information System (GIS) professionals, complex wide within the Department, conduct spatial information management practices on a daily basis to complete a wide variety of science and engineering tasks. The DOE Office of the CIO recognized the wealth of geospatial information management knowledge within the DOE complex and formed the DOE GIS Core Team in 2001 as a result. The team is comprised of GIS experts-representing all major DOE labs, site facilities, and programs-who volunteer their time to address issues impacting the entire complex. These include the President's management agenda (with emphasis on the Geospatial One-Stop), homeland security, emergency response, site management, software and geospatial data licensing, and federal, national, and international standards governing the creation and dissemination of geospatial data. The strength of the DOE GIS Core Team is the wide diversity of GIS and scientific expertise represented on the team, which allows it to provide the DOE CIO's office with sound guidance on complex wide issues from a GIS practitioner's perspective. The Core Team's mission is 'to foster technical excellence and communication, to identify and advocate best business practices, and to provide sound recommendations on policy and standards.' As a first step toward identifying best practices the feam conducted a survey of all known GIS assets across the DOE complex. The survey identified each site's GIS expertise, operating systems architecture and software applications, major project areas supported, and a number of other metrics important to the operation of a GIS organization. Results of the survey will be discussed, along with the mission of the Core Team. A broad overview of best practices utilized by many of the leading GIS organizations across the complex will also be provided.

  4. Gas core nuclear rocket feasibility project

    SciTech Connect (OSTI)

    Howe, S.D.; DeVolder, B.; Thode, L.; Zerkle, D.

    1997-09-01

    The next giant leap for mankind will be the human exploration of Mars. Almost certainly within the next thirty years, a human crew will brave the isolation, the radiation, and the lack of gravity to walk on and explore the Red planet. However, because the mission distances and duration will be hundreds of times greater than the lunar missions, a human crew will face much greater obstacles and a higher risk than those experienced during the Apollo program. A single solution to many of these obstacles is to dramatically decrease the mission duration by developing a high performance propulsion system. The gas core nuclear rocket (GCNR) has the potential to be such a system. The gas core concept relies on the use of fluid dynamic forces to create and maintain a vortex. The vortex is composed of a fissile material which will achieve criticality and produce high power levels. By radiatively coupling to the surrounding fluids, extremely high temperatures in the propellant and, thus, high specific impulses can be generated. The ship velocities enabled by such performance may allow a 9 month round trip, manned Mars mission to be considered. Alternatively, one might consider slightly longer missions in ships that are heavily shielded against the intense Galactic Cosmic Ray flux to further reduce the radiation dose to the crew. The current status of the research program at the Los Alamos National Laboratory into the gas core nuclear rocket feasibility will be discussed.

  5. Measurement of Electromagnetic Parameters and FDTD Modeling of Ferrite Cores

    E-Print Network [OSTI]

    Koledintseva, Marina Y.

    .He@lairdtech.com; Bill.Matlin@lairdtech.com Abstract--The paper describes a methodology for an efficient design of novel products based on magneto-dielectric (ferrite) materials with desirable frequency responses that satisfy EMC and SI requirements. The methodology starts from estimating complex permittivity and permeability

  6. An evaluation of concurrency control with one thousand cores

    E-Print Network [OSTI]

    Yu, Xiangyao

    2015-01-01

    Computer architectures are moving towards an era dominated by many-core machines with dozens or even hundreds of cores on a single chip. This unprecedented level of on-chip parallelism introduces a new dimension to scalability ...

  7. Magnetic Vortex Core Reversal by Low-Field Excitations

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

    Magnetic Vortex Core Reversal by Low-Field Excitations Magnetic Vortex Core Reversal by Low-Field Excitations Print Wednesday, 28 March 2007 00:00 In micrometer-sized magnetic thin...

  8. Core Lithology State of Hawail Scientific Observation Hole 2...

    Open Energy Info (EERE)

    Core Lithology State of Hawail Scientific Observation Hole 2 Kilauea Volcano, Hawaii Jump to: navigation, search OpenEI Reference LibraryAdd to library Report: Core Lithology State...

  9. Core Lithology State of Hawaii Scientific Observation Hole 4...

    Open Energy Info (EERE)

    Core Lithology State of Hawaii Scientific Observation Hole 4 Kilauea Volcano, Hawaii Jump to: navigation, search OpenEI Reference LibraryAdd to library Report: Core Lithology State...

  10. Core Lithology From the State of Hawaii Scientific Observation...

    Open Energy Info (EERE)

    Core Lithology From the State of Hawaii Scientific Observation Hole 1, Kilauea Volcano, Hawaii Jump to: navigation, search OpenEI Reference LibraryAdd to library Report: Core...

  11. Mineral Deformation at Earth's Core-Mantle Boundary

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

    for its liquid-iron outer core), this convection causes deformation of solid rocks by plastic flow. At the core-mantle boundary (CMB), 2900 km deep, seismologists have discovered...

  12. STRUCTURE OF THE SUN'S CORE: EVOLUTIONAL AND SEISMOLOGICAL CONSTRAINTS

    E-Print Network [OSTI]

    ­generating core where the thermonuclear reactions are significant; there is definitely variable hydrogen approximate, of course. We set the core's upper boundary at 10 million K assuming that thermonuclear reactions

  13. LabVIEW Core 2 Course | Jefferson Lab

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

    LabVIEW Core 2 Course The Lab is advertising a LabVIEW Core 2 course coming to Newport News. Date: Next Thursday and Friday (716, 717) from 8 to 5 at the Canon facility location,...

  14. Mineral Deformation at Earth's Core-Mantle Boundary

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

    Because Earth is mostly solid (except for its liquid-iron outer core), this convection causes deformation of solid rocks by plastic flow. At the core-mantle boundary (CMB), 2900 km...

  15. Armored spring-core superconducting cable and method of construction

    DOE Patents [OSTI]

    McIntyre, Peter M. (611 Montclair, College Station, TX 77840); Soika, Rainer H. (1 Hensel, #X4C, College Station, TX 77840)

    2002-01-01

    An armored spring-core superconducting cable (12) is provided. The armored spring-core superconducting cable (12) may include a spring-core (20), at least one superconducting strand (24) wound onto the spring-core (20), and an armored shell (22) that encases the superconducting strands (24). The spring-core (20) is generally a perforated tube that allows purge gases and cryogenic liquids to be circulated through the armored superconducting cable (12), as well as managing the internal stresses within the armored spring-core superconducting cable (12). The armored shell (22) manages the external stresses of the armored spring-core superconducting cable (12) to protect the fragile superconducting strands (24). The armored spring-core superconducting cable (12) may also include a conductive jacket (34) formed outwardly of the armored shell (22).

  16. Drilling and coring methods that minimize the disturbance of...

    Office of Scientific and Technical Information (OSTI)

    Drilling and coring methods that minimize the disturbance of cuttings, core, and rock formation in the unsaturated zone, Yucca Mountain, Nevada Hammermeister, D.P.; Blout, D.O.;...

  17. Axion dark matter, solitons, and the cusp-core problem

    E-Print Network [OSTI]

    Marsh, David J E

    2015-01-01

    Self-gravitating bosonic fields can support stable and localised field configurations. For real fields, these solutions oscillate in time and are known as oscillatons. The density profile is static, and is soliton. Such solitons should be ubiquitous in models of axion dark matter, with the soliton characteristic mass and size depending on some inverse power of the axion mass. Stable configurations of non-relativistic axions are studied numerically using the Schr\\"{o}dinger-Poisson system. This method, and the resulting soliton density profiles, are reviewed. Using a scaling symmetry and the uncertainty principle, the core size of the soliton can be related to the central density and axion mass, $m_a$, in a universal way. Solitons have a constant central density due to pressure-support, unlike the cuspy profile of cold dark matter (CDM). One consequence of this fact is that solitons composed of ultra-light axions (ULAs) may resolve the `cusp-core' problem of CDM. In DM halos, thermodynamics will lead to a CDM-...

  18. Criticality Safety Code Validation with LWBR’s SB Cores

    SciTech Connect (OSTI)

    Putman, Valerie Lee

    2003-01-01

    The first set of critical experiments from the Shippingport Light Water Breeder Reactor Program included eight, simple geometry critical cores built with 233UO2-ZrO2, 235UO2-ZrO2, ThO2, and ThO2-233UO2 nuclear materials. These cores are evaluated, described, and modeled to provide benchmarks and validation information for INEEL criticality safety calculation methodology. In addition to consistency with INEEL methodology, benchmark development and nuclear data are consistent with International Criticality Safety Benchmark Evaluation Project methodology.Section 1 of this report introduces the experiments and the reason they are useful for validating some INEEL criticality safety calculations. Section 2 provides detailed experiment descriptions based on currently available experiment reports. Section 3 identifies criticality safety validation requirement sources and summarizes requirements that most affect this report. Section 4 identifies relevant hand calculation and computer code calculation methodologies used in the experiment evaluation, benchmark development, and validation calculations. Section 5 provides a detailed experiment evaluation. This section identifies resolutions for currently unavailable and discrepant information. Section 5 also reports calculated experiment uncertainty effects. Section 6 describes the developed benchmarks. Section 6 includes calculated sensitivities to various benchmark features and parameters. Section 7 summarizes validation results. Appendices describe various assumptions and their bases, list experimenter calculations results for items that were independently calculated for this validation work, report other information gathered and developed by SCIENTEC personnel while evaluating these same experiments, and list benchmark sample input and miscellaneous supplementary data.

  19. Impact of the symmetry energy on nuclear pasta phases and crust-core transition in neutron stars

    E-Print Network [OSTI]

    S. S. Bao; H. Shen

    2015-01-14

    We study the impact of the symmetry energy on properties of nuclear pasta phases and crust-core transition in neutron stars. We perform a self-consistent Thomas--Fermi calculation employing the relativistic mean-field model. The properties of pasta phases presented in the inner crust of neutron stars are investigated and the crust-core transition is examined. It is found that the slope of the symmetry energy plays an important role in determining the pasta phase structure and the crust-core transition. The correlation between the symmetry energy slope and the crust-core transition density obtained in the Thomas--Fermi approximation is consistent with that predicted by the liquid-drop model.

  20. An Analysis of Core Networks among First-Generation Immigrants

    E-Print Network [OSTI]

    Osuji, Chinyere K.

    2006-01-01

    A. Haines, and John J. Beggs. 2000. "Core Networks and Tieof support (Hurlbert, Haines and Beggs 2000; Marsden 1987).

  1. Cores and cusps in warm dark matter halos

    SciTech Connect (OSTI)

    Villaescusa-Navarro, Francisco [IFIC, Universidad de Valencia-CSIC, E-46071, Valencia (Spain); Dalal, Neal, E-mail: villa@ific.uv.es, E-mail: neal@cita.utoronto.ca [Canadian Institute for Theoretical Astrophysics, University of Toronto, 60 St. George St., Toronto, ON, M5S3H8 (Canada)

    2011-03-01

    The apparent presence of large core radii in Low Surface Brightness galaxies has been claimed as evidence in favor of warm dark matter. Here we show that WDM halos do not have cores that are large fractions of the halo size: typically, r{sub core}/r{sub 200}?<10{sup ?3}. This suggests an astrophysical origin for the large cores observed in these galaxies, as has been argued by other authors.

  2. Neutrino-driven supernova of a low-mass iron-core progenitor boosted by three-dimensional turbulent convection

    E-Print Network [OSTI]

    Tobias Melson; Hans-Thomas Janka; Andreas Marek

    2015-02-19

    We present the first successful simulation of a neutrino-driven supernova explosion in three dimensions (3D), using the Prometheus-Vertex code with an axis-free Yin-Yang grid and a sophisticated treatment of three-flavor, energy-dependent neutrino transport. The progenitor is a nonrotating, zero-metallicity 9.6 Msun star with an iron core. While in spherical symmetry outward shock acceleration sets in later than 300 ms after bounce, a successful explosion starts at ~130 ms postbounce in two dimensions (2D). The 3D model explodes at about the same time but with faster shock expansion than in 2D and a more quickly increasing and roughly 10 percent higher explosion energy of >10^50 erg. The more favorable explosion conditions in 3D are explained by lower temperatures and thus reduced neutrino emission in the cooling layer below the gain radius. This moves the gain radius inward and leads to a bigger mass in the gain layer, whose larger recombination energy boosts the explosion energy in 3D. These differences are caused by less coherent, less massive, and less rapid convective downdrafts associated with postshock convection in 3D. The less violent impact of these accretion downflows in the cooling layer produces less shock heating and therefore diminishes energy losses by neutrino emission. We thus have, for the first time, identified a reduced mass accretion rate, lower infall velocities, and a smaller surface filling factor of convective downdrafts as consequences of 3D postshock turbulence that facilitate neutrino-driven explosions and strengthen them compared to the 2D case.

  3. Gas-like state of $?$ clusters around $^{16}$O core in $^{24}$Mg

    E-Print Network [OSTI]

    T. Ichikawa; N. Itagaki; T. Kawabata; Tz. Kokalova; W. von Oertzen

    2011-02-08

    We have studied gas-like states of $\\alpha$ clusters around an $^{16}$O core in $^{24}$Mg based on a microscopic $\\alpha$-cluster model. This study was performed by introducing a Monte Carlo technique for the description of the THSR (Tohsaki Horiuchi Schuck R\\"{o}pke) wave function, and the coupling effect to other low-lying cluster states was taken into account. A large isoscalar monopole ($E0$) transition strength from the ground to the gas-like state is discussed. The gas-like state of two $\\alpha$ clusters in $^{24}$Mg around the $^{16}$O core appears slightly below the 2$\\alpha$-threshold e

  4. Preliminary calculations on direct heating of a containment atmosphere by airborne core debris

    SciTech Connect (OSTI)

    Pilch, M.; Tarbell, W.W.

    1986-07-01

    Direct heating of the containment atmosphere by airborne core debris may be a significant source of containment pressurization in those accident sequences where the primary system is still at high pressure when the RPV fails. Vigorous blowdown of the primary system may result in nearly complete relocation of core debris out of the reactor cavity and possibly into the containment atmosphere where the liberation of thermal and chemical energy can directly heat the atmosphere. Rate independent and rate dependent models are developed and exercised parametrically to quantify the possible magnitude and rate of containment pressurization from direct heating. The possible mitigative effects of airborne water and subcompartment heating are also investigated.

  5. Simulated properties of Kagomee and tetragonal truss core panels

    E-Print Network [OSTI]

    Torquato, Salvatore

    Simulated properties of Kagomee and tetragonal truss core panels S. Hyun a , A.M. Karlsson b , S September 2002 Abstract The finite element method has been used to simulate the properties of panels hardening. It is shown that the Kagomee core is more resistant to plastic buckling than the tetragonal core

  6. Gearing Up for the Common Core State Standards in Mathematics

    E-Print Network [OSTI]

    McGraw, Rebecca

    Gearing Up for the Common Core State Standards in Mathematics William McCallum The University of Arizona Tucson, 1 April 2011 William McCallumThe University of Arizona Gearing Up for the Common CoreCallumThe University of Arizona Gearing Up for the Common Core State Standards in Mathematics #12;How do we achieve

  7. WEB OF SCIENCETM CORE COLLECTION Guide de rfrence

    E-Print Network [OSTI]

    Laval, Université

    1 WEB OF SCIENCETM CORE COLLECTION Guide de référence Qu'est-ce que le Web of Science Core GÉNÉRALE Recherche Combiner des mots et des expressions pour rechercher dans le Web of science Core menu déroulant pour rechercher une autre base dans le « Web of Science ». Limiter votre recherche

  8. University of Illinois College of Medicine THIRD YEAR CORE CLERKSHIP

    E-Print Network [OSTI]

    Jain, Kanti

    University of Illinois College of Medicine THIRD YEAR CORE CLERKSHIP GRADE SCALE Academic Year 2014;University of Illinois College of Medicine THIRD YEAR CORE CLERKSHIP GRADE SCALE Academic Year 2014 May 2014 #12;University of Illinois College of Medicine THIRD YEAR CORE CLERKSHIP GRADE SCALE Academic

  9. The Vital Core Connectivity Problem Sylvia Boyd and Amy Cameron

    E-Print Network [OSTI]

    Boyd, Sylvia

    The Vital Core Connectivity Problem Sylvia Boyd and Amy Cameron School of Information Technology) are partitioned into two classes ­ vital vertices, which represent the vital core of the network, and secondary vertices. We consider the vital core connectivity problem (VCC), which is the problem of finding a minimum

  10. Collapse and fragmentation of magnetic molecular cloud cores with the Enzo AMR MHD code. II. Prolate and oblate cores

    SciTech Connect (OSTI)

    Boss, Alan P.; Keiser, Sandra A.

    2014-10-10

    We present the results of a large suite of three-dimensional models of the collapse of magnetic molecular cloud cores using the adaptive mesh refinement code Enzo2.2 in the ideal magnetohydrodynamics approximation. The cloud cores are initially either prolate or oblate, centrally condensed clouds with masses of 1.73 or 2.73 M {sub ?}, respectively. The radial density profiles are Gaussian, with central densities 20 times higher than boundary densities. A barotropic equation of state is used to represent the transition from low density isothermal phases, to high density optically thick phases. The initial magnetic field strength ranges from 6.3 to 100 ?G, corresponding to clouds that are strongly to marginally supercritical, respectively, in terms of the mass to magnetic flux ratio. The magnetic field is initially uniform and aligned with the clouds' rotation axes, with initial ratios of rotational to gravitational energy ranging from 10{sup –4} to 0.1. Two significantly different outcomes for collapse result: (1) formation of single protostars with spiral arms, and (2) fragmentation into multiple protostar systems. The transition between these two outcomes depends primarily on the initial magnetic field strength, with fragmentation occurring for mass to flux ratios greater than about 14 times the critical ratio for prolate clouds. Oblate clouds typically fragment into several times more clumps than prolate clouds. Multiple, rather than binary, system formation is the general rule in either case, suggesting that binary stars are primarily the result of the orbital dissolution of multiple protostar systems.

  11. Validation Results for Core-Scale Oil Shale Pyrolysis

    SciTech Connect (OSTI)

    Staten, Josh; Tiwari, Pankaj

    2015-03-01

    This report summarizes a study of oil shale pyrolysis at various scales and the subsequent development a model for in situ production of oil from oil shale. Oil shale from the Mahogany zone of the Green River formation was used in all experiments. Pyrolysis experiments were conducted at four scales, powdered samples (100 mesh) and core samples of 0.75”, 1” and 2.5” diameters. The batch, semibatch and continuous flow pyrolysis experiments were designed to study the effect of temperature (300°C to 500°C), heating rate (1°C/min to 10°C/min), pressure (ambient and 500 psig) and size of the sample on product formation. Comprehensive analyses were performed on reactants and products - liquid, gas and spent shale. These experimental studies were designed to understand the relevant coupled phenomena (reaction kinetics, heat transfer, mass transfer, thermodynamics) at multiple scales. A model for oil shale pyrolysis was developed in the COMSOL multiphysics platform. A general kinetic model was integrated with important physical and chemical phenomena that occur during pyrolysis. The secondary reactions of coking and cracking in the product phase were addressed. The multiscale experimental data generated and the models developed provide an understanding of the simultaneous effects of chemical kinetics, and heat and mass transfer on oil quality and yield. The comprehensive data collected in this study will help advance the move to large-scale in situ oil production from the pyrolysis of oil shale.

  12. The Sensitivity of Core-Collapse Supernovae to Nuclear Electron Capture

    E-Print Network [OSTI]

    Sullivan, Chris; Zegers, Remco G T; Grubb, Thomas; Austin, Sam M

    2015-01-01

    A weak-rate library aimed at investigating the sensitivity of astrophysical environments to variations of electron-capture rates on medium-heavy nuclei has been developed. With this library, the sensitivity of the core-collapse and early post-bounce phases of core-collapse supernovae to nuclear electron-capture is examined by systematically and statistically varying electron-capture rates of individual nuclei. The rates are adjusted by factors consistent with uncertainties indicated by comparing theoretical rates to those deduced from charge-exchange and $\\beta$-decay measurements. To ensure a model independent assessment, sensitivity studies across a comprehensive set of progenitors and equations of state are performed. In our systematic study, we find a +16/-4 % range in the mass of the inner-core at the time of shock formation and a $\\pm$20% range of peak {\

  13. Nitrate ions spikes in ice cores are not suitable proxies for solar proton events

    E-Print Network [OSTI]

    Duderstadt, Katharine A; Jackman, Charles H; Randall, Cora E; Schwadron, Nathan A; Solomon, Stanley C; Spence, Harlan E; Yudin, Valery A

    2015-01-01

    Nitrate ion spikes in polar ice cores are contentiously used to estimate the intensity, frequency, and probability of historical solar proton events, quantities that are needed to prepare for potentially society-crippling space weather events. We use the Whole Atmosphere Community Climate Model to calculate how large an event would have to be to produce enough odd nitrogen throughout the atmosphere to be discernible as nitrate peaks at the Earth's surface. These hypothetically large events are compared with probability of occurrence estimates derived from measured events, sunspot records, and cosmogenic radionuclides archives. We conclude that the fluence and spectrum of solar proton events necessary to produce odd nitrogen enhancements equivalent to the spikes of nitrate ions in Greenland ice cores are unlikely to have occurred throughout the Holocene, confirming that nitrate ions in ice cores are not suitable proxies for historical individual solar proton events.

  14. Towards a Synthesis of Core-Collapse Supernova Theory

    E-Print Network [OSTI]

    Adam Burrows

    1996-06-06

    New insights into the mechanism and character of core--collapse supernova explosions are transforming the approach of theorists to their subject. The universal realization that the direct hydrodynamic mechanism does not work and that a variety of hydrodynamic instabilities can influence the viability of theoretical explosions has ushered in a new era in supernova modeling. In this paper, I discuss the important physical and technical issues that remain. I review the neutrino--driven mechanism, the possible roles of Rayleigh--Taylor instabilities, questions in neutrino transport, and the various observational constraints within which theorists must operate. However, a consensus has yet to be achieved among active workers concerning many important details and some essential phenomenology. This synopsis is meant to accomplish two things: 1) to focus attention on the interesting problems whose resolution will bring needed progress, and 2) to assess the current status of the theoretical art.

  15. Formation of accretion centers in simulations of colliding uniform density H$_2$ cores

    E-Print Network [OSTI]

    Arreaga-Garcia, G

    2015-01-01

    We test here the first stage of a route of modifications to be applied to the public GADGET2 code for dynamically identifying accretion centers during the collision process of two adjacent and identical gas cores. Each colliding core has a uniform density profile and rigid body rotation; its mass and size have been chosen to represent the observed core $L1544$; for the thermal and rotational energy ratios with respect to the potential energy, we assume the values $\\alpha=0.3$ and $\\beta=0.1$, respectively. These values favor the gravitational collapse of the core. We here study cases of both -head-on and off-center collisions, in which the pre-collision velocity increases the initial sound speed of the barotropic gas by up to several times. In a simulation the accretion centers are formed by the highest density particles, so we here report their location and properties in order to realize the collision effects on the collapsing and colliding cores. In one of the models we observe a roughly spherical distribut...

  16. ISOTROPIC HEATING OF GALAXY CLUSTER CORES VIA RAPIDLY REORIENTING ACTIVE GALACTIC NUCLEUS JETS

    SciTech Connect (OSTI)

    Babul, Arif; Sharma, Prateek; Reynolds, Christopher S.

    2013-05-01

    Active galactic nucleus (AGN) jets carry more than sufficient energy to stave off catastrophic cooling of the intracluster medium (ICM) in the cores of cool-core clusters. However, in order to prevent catastrophic cooling, the ICM must be heated in a near-isotropic fashion and narrow bipolar jets with P{sub jet} = 10{sup 44-45} erg s{sup -1}, typical of radio AGNs at cluster centers, are inefficient in heating the gas in the transverse direction to the jets. We argue that due to existent conditions in cluster cores, the supermassive black holes (SMBHs) will, in addition to accreting gas via radiatively inefficient flows, experience short stochastic episodes of enhanced accretion via thin disks. In general, the orientation of these accretion disks will be misaligned with the spin axis of the black holes (BHs) and the ensuing torques will cause the BH's spin axis (and therefore the jet axis) to slew and rapidly change direction. This model not only explains recent observations showing successive generations of jet-lobes-bubbles in individual cool-core clusters that are offset from each other in the angular direction with respect to the cluster center, but also shows that AGN jets can heat the cluster core nearly isotropically on the gas cooling timescale. Our model does require that the SMBHs at the centers of cool-core clusters be spinning relatively slowly. Torques from individual misaligned disks are ineffective at tilting rapidly spinning BHs by more than a few degrees. Additionally, since SMBHs that host thin accretion disks will manifest as quasars, we predict that roughly 1-2 rich clusters within z < 0.5 should have quasars at their centers.

  17. Investigation on the Core Bypass Flow in a Very High Temperature Reactor

    SciTech Connect (OSTI)

    Hassan, Yassin

    2013-10-22

    Uncertainties associated with the core bypass flow are some of the key issues that directly influence the coolant mass flow distribution and magnitude, and thus the operational core temperature profiles, in the very high-temperature reactor (VHTR). Designers will attempt to configure the core geometry so the core cooling flow rate magnitude and distribution conform to the design values. The objective of this project is to study the bypass flow both experimentally and computationally. Researchers will develop experimental data using state-of-the-art particle image velocimetry in a small test facility. The team will attempt to obtain full field temperature distribution using racks of thermocouples. The experimental data are intended to benchmark computational fluid dynamics (CFD) codes by providing detailed information. These experimental data are urgently needed for validation of the CFD codes. The following are the project tasks: • Construct a small-scale bench-top experiment to resemble the bypass flow between the graphite blocks, varying parameters to address their impact on bypass flow. Wall roughness of the graphite block walls, spacing between the blocks, and temperature of the blocks are some of the parameters to be tested. • Perform CFD to evaluate pre- and post-test calculations and turbulence models, including sensitivity studies to achieve high accuracy. • Develop the state-of-the art large eddy simulation (LES) using appropriate subgrid modeling. • Develop models to be used in systems thermal hydraulics codes to account and estimate the bypass flows. These computer programs include, among others, RELAP3D, MELCOR, GAMMA, and GAS-NET. Actual core bypass flow rate may vary considerably from the design value. Although the uncertainty of the bypass flow rate is not known, some sources have stated that the bypass flow rates in the Fort St. Vrain reactor were between 8 and 25 percent of the total reactor mass flow rate. If bypass flow rates are on the high side, the quantity of cooling flow through the core may be considerably less than the nominal design value, causing some regions of the core to operate at temperatures in excess of the design values. These effects are postulated to lead to localized hot regions in the core that must be considered when evaluating the VHTR operational and accident scenarios.

  18. Hydrogen issue in Core Collapse Supernovae

    E-Print Network [OSTI]

    A. Elmhamdi; I. J. Danziger; D. Branch; B. Leibundgut

    2006-11-06

    We discuss results of analyzing a time series of selected photospheric-optical spectra of core collapse supernovae (CCSNe). This is accomplished by means of the parameterized supernovae synthetic spectrum (SSp) code ``SYNOW''. Special attention is addressed to traces of hydrogen at early phases, especially for the stripped-envelope SNe (i.e. SNe Ib-c). A thin low mass hydrogen layer extending to very high ejection velocities above the helium shell, is found to be the most likely scenario for Type Ib SNe.

  19. Droplet generation during core reflood. [PWR

    SciTech Connect (OSTI)

    Kocamustafaogullari, G.; De Jarlais, G.; Ishii, M.

    1983-01-01

    The process of entrainment and disintegration of liquid droplets by a flow of steam has considerable practical importance in calculating the effectivenes of the emergency core cooling system. Liquid entrainment is also important in determination of the critical heat flux point in general. Thus the analysis of the reflooding phase of a LOCA requires detailed knowledge of droplet size. Droplet size is mainly determined by the droplet generation mechanisms involved. To study these mechanisms, data generated in the PWR FLECHT SEASET series of experiments was analyzed. In addition, an experiment was performed in which the hydrodynamics of low quality post-CHF flow (inverted annular flow) were simulated in an adiabatic test section.

  20. Hunton Group core workshop and field trip

    SciTech Connect (OSTI)

    Johnson, K.S.

    1993-12-31

    The Late Ordovician-Silurian-Devonian Hunton Group is a moderately thick sequence of shallow-marine carbonates deposited on the south edge of the North American craton. This rock unit is a major target for petroleum exploration and reservoir development in the southern Midcontinent. The workshop described here was held to display cores, outcrop samples, and other reservoir-characterization studies of the Hunton Group and equivalent strata throughout the region. A field trip was organized to complement the workshop by allowing examination of excellent outcrops of the Hunton Group of the Arbuckle Mountains.

  1. Core File Settings | Argonne Leadership Computing Facility

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would like submit the followingConcentratingPortalCool MagneticCopper Palladium-Core File

  2. SoCore Energy | 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 Home Page| Open Energy Information Serbia-Enhancing Capacity forSilicium de ProvenceSolarProject JumpCounty, Pennsylvania:SoCore

  3. Over Core Stress | 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 Home Page on QA:QAsource History ViewMayo, Maryland:NPIProtectio Program | OpenWisconsin:NewOver Core Stress Jump to: navigation,

  4. Core Values Postcard | The Ames 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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room News PublicationsAuditsClusterInformationContract Managementthermoelectric powerTheCore Values

  5. SolviCore | 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 Home Page on QA:QA J-E-1 SECTION J APPENDIX ECoop Inc JumpHeter BatterySolarfin Jump to:Solkar Solar IndustrySolviCore Jump to:

  6. Fermilab | Illinois Accelerator Research Center | Fermilab Core

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail.Theory ofDid you not find whatGasEnergy TechnologiesCapabilities Core

  7. Design exploration: engaging a larger user population 

    E-Print Network [OSTI]

    Moore, John Michael

    2009-06-02

    xii Page APPENDIX A DESIGN EXPLORATION STOPWORDS ..........................................125 APPENDIX B ANALYZER STUDY TUTORIALS ....................................................126 APPENDIX C ANALYZER STUDY SCENARIOS...

  8. The LASS (Larger Aperture Superconducting Solenoid) spectrometer

    SciTech Connect (OSTI)

    Aston, D.; Awaji, N.; Barnett, B.; Bienz, T.; Bierce, R.; Bird, F.; Bird, L.; Blockus, D.; Carnegie, R.K.; Chien, C.Y.

    1986-04-01

    LASS is the acronym for the Large Aperture Superconducting Solenoid spectrometer which is located in an rf-separated hadron beam at the Stanford Linear Accelerator Center. This spectrometer was constructed in order to perform high statistics studies of multiparticle final states produced in hadron reactions. Such reactions are frequently characterized by events having complicated topologies and/or relatively high particle multiplicity. Their detailed study requires a spectrometer which can provide good resolution in momentum and position over almost the entire solid angle subtended by the production point. In addition, good final state particle identification must be available so that separation of the many kinematically-overlapping final states can be achieved. Precise analyses of the individual reaction channels require high statistics, so that the spectrometer must be capable of high data-taking rates in order that such samples can be acquired in a reasonable running time. Finally, the spectrometer must be complemented by a sophisticated off-line analysis package which efficiently finds tracks, recognizes and fits event topologies and correctly associates the available particle identification information. This, together with complicated programs which perform specific analysis tasks such as partial wave analysis, requires a great deal of software effort allied to a very large computing capacity. This paper describes the construction and performance of the LASS spectrometer, which is an attempt to realize the features just discussed. The configuration of the spectrometer corresponds to the data-taking on K and K interactions in hydrogen at 11 GeV/c which took place in 1981 and 1982. This constitutes a major upgrade of the configuration used to acquire lower statistics data on 11 GeV/c K p interactions during 1977 and 1978, which is also described briefly.

  9. Should we geoengineer larger ice caps?

    E-Print Network [OSTI]

    Haqq-Misra, Jacob

    2015-01-01

    The climate of Earth is susceptible to catastrophes that could threaten the longevity of human civilization. Geoengineering to reduce incoming solar radiation has been suggested as a way to mediate the warming effects of contemporary climate change, but a geoengineering program for thousands of years could also be used to enlarge the size of the polar ice caps and create a permanently cooler climate. Such a large ice cap state would make Earth less susceptible to climate threats and could allow human civilization to survive further into the future than otherwise possible. Intentionally extending Earth's glacial coverage will require uninterrupted commitment to this program for millenia but would ultimately reach a cooler equilibrium state where geoengineering is no longer needed. Whether or not this program is ever attempted, this concept illustrates the need to identify preference among potential climate states to ensure the long-term success of civilization.

  10. Sabourov_2006 (much larger file).pdf

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust, High-Throughput Analysis of Protein1-0845*RV6STATDecember 2, 2014 Jose,SUSS PMAmanda

  11. Mass-radius relations and core-envelope decompositions of super-Earths and sub-Neptunes

    SciTech Connect (OSTI)

    Howe, Alex R.; Burrows, Adam; Verne, Wesley E-mail: burrows@astro.princeton.edu

    2014-06-01

    Many exoplanets have been discovered with radii of 1-4 R {sub ?}, between that of Earth and Neptune. A number of these are known to have densities consistent with solid compositions, while others are 'sub-Neptunes' likely to have significant H{sub 2}-He envelopes. Future surveys will no doubt significantly expand these populations. In order to understand how the measured masses and radii of such planets can inform their structures and compositions, we construct models both for solid layered planets and for planets with solid cores and gaseous envelopes, exploring a range of core masses, H{sub 2}-He envelope masses, and associated envelope entropies. For planets in the super-Earth/sub-Neptune regime for which both radius and mass are measured, we estimate how each is partitioned into a solid core and gaseous envelope, associating a specific core mass and envelope mass with a given exoplanet. We perform this decomposition for both ''Earth-like'' rock-iron cores and pure ice cores, and find that the necessary gaseous envelope masses for this important sub-class of exoplanets must range very widely from zero to many Earth masses, even for a given core mass. This result bears importantly on exoplanet formation and envelope evaporation processes.

  12. A Neutrino-Driven Core Collapse Supernova Explosion of a 15 M Star

    E-Print Network [OSTI]

    Mezzacappa, Anthony; Bruenn, Stephen W; Hix, W Raphael; Messer, O E Bronson; Endeve, Eirik; Blondin, John M; Harris, J Austin; Marronetti, Pedro; Yakunin, Konstantin N; Lingerfelt, Eric J

    2015-01-01

    We present results from an ab initio three-dimensional, multi-physics core collapse supernova simulation for the case of a 15 M progenitor. Our simulation includes multi-frequency neutrino transport with state-of-the-art neutrino interactions in the "ray-by-ray" approximation, and approximate general relativity. Our model exhibits a neutrino-driven explosion. The shock radius begins an outward trajectory at approximately 275 ms after bounce, giving the first indication of a developing explosion in the model. The onset of this shock expansion is delayed relative to our two-dimensional counterpart model, which begins at approximately 200 ms after core bounce. At a time of 441 ms after bounce, the angle-averaged shock radius in our three-dimensional model has reached 751 km. Further quantitative analysis of the outcomes in this model must await further development of the post-bounce dynamics and a simulation that will extend well beyond 1 s after stellar core bounce, based on the results for the same progenitor ...

  13. 1.2 CORE INTERPRETATION AND SEDIMENTOLOGICAL ANALYSIS 1.2.1 Generalized Core Description

    E-Print Network [OSTI]

    Schechter, David S.

    reservoir quality. Carbonate rocks are not very common in the analyzed cores. Lithofacies L2: Shales. Shale infrequently; the black color of these shales is a function of their high organic carbon content. Organics siltstone. This lithofacies is characterized by alternations of light and dark colored fine laminae, each

  14. Core-annular flow through a horizontal pipe: Hydrodynamic counterbalancing of buoyancy force on core

    E-Print Network [OSTI]

    Vuik, Kees

    it was successfully applied for pipeline transport of very viscous oil. The low-viscosity liquid in these cases was water. The pressure drop over the pipeline was considerably lower for oil-water core-annular flow than the pressure drop for the flow of oil alone at the same mean oil velocity. Much attention has been paid

  15. Thermally Stable Nanocatalyst for High Temperature Reactions: Pt-Mesoporous Silica Core-Shell Nanoparticles

    SciTech Connect (OSTI)

    Joo, Sang Hoon; Park, J.Y.; Tsung, C.-K.; Yamada, Y.; Yang, P.; Somorjai, G.A.

    2008-10-25

    Recent advances in colloidal synthesis enabled the precise control of size, shape and composition of catalytic metal nanoparticles, allowing their use as model catalysts for systematic investigations of the atomic-scale properties affecting catalytic activity and selectivity. The organic capping agents stabilizing colloidal nanoparticles, however, often limit their application in high-temperature catalytic reactions. Here we report the design of a high-temperature stable model catalytic system that consists of Pt metal core coated with a mesoporous silica shell (Pt{at}mSiO{sub 2}). While inorganic silica shells encaged the Pt cores up to 750 C in air, the mesopores directly accessible to Pt cores made the Pt{at}mSiO{sub 2} nanoparticles as catalytically active as bare Pt metal for ethylene hydrogenation and CO oxidation. The high thermal stability of Pt{at}mSiO{sub 2} nanoparticles permitted high-temperature CO oxidation studies, including ignition behavior, which was not possible for bare Pt nanoparticles because of their deformation or aggregation. The results suggest that the Pt{at}mSiO{sub 2} nanoparticles are excellent nanocatalytic systems for high-temperature catalytic reactions or surface chemical processes, and the design concept employed in the Pt{at}mSiO{sub 2} core-shell catalyst can be extended to other metal-metal oxide compositions.

  16. A Two-Step Approach to Uncertainty Quantification of Core Simulators

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

    Yankov, Artem; Collins, Benjamin; Klein, Markus; Jessee, Matthew A.; Zwermann, Winfried; Velkov, Kiril; Pautz, Andreas; Downar, Thomas

    2012-01-01

    For the multiple sources of error introduced into the standard computational regime for simulating reactor cores, rigorous uncertainty analysis methods are available primarily to quantify the effects of cross section uncertainties. Two methods for propagating cross section uncertainties through core simulators are the XSUSA statistical approach and the “two-step” method. The XSUSA approach, which is based on the SUSA code package, is fundamentally a stochastic sampling method. Alternatively, the two-step method utilizes generalized perturbation theory in the first step and stochastic sampling in the second step. The consistency of these two methods in quantifying uncertainties in the multiplication factor andmore »in the core power distribution was examined in the framework of phase I-3 of the OECD Uncertainty Analysis in Modeling benchmark. With the Three Mile Island Unit 1 core as a base model for analysis, the XSUSA and two-step methods were applied with certain limitations, and the results were compared to those produced by other stochastic sampling-based codes. Based on the uncertainty analysis results, conclusions were drawn as to the method that is currently more viable for computing uncertainties in burnup and transient calculations.« less

  17. Heat transfer in sunspot penumbrae. Origin of dark-cored penumbral filaments

    E-Print Network [OSTI]

    B. Ruiz Cobo; L. R. Bellot Rubio

    2008-10-07

    Context: Observations at 0.1" have revealed the existence of dark cores in the bright filaments of sunspot penumbrae. Expectations are high that such dark-cored filaments are the basic building blocks of the penumbra, but their nature remains unknown. Aims: We investigate the origin of dark cores in penumbral filaments and the surplus brightness of the penumbra. To that end we use an uncombed penumbral model. Methods: The 2D stationary heat transfer equation is solved in a stratified atmosphere consisting of nearly horizontal magnetic flux tubes embedded in a stronger and more vertical field. The tubes carry an Evershed flow of hot plasma. Results: This model produces bright filaments with dark cores as a consequence of the higher density of the plasma inside the tubes, which shifts the surface of optical depth unity toward higher (cooler) layers. Our calculations suggest that the surplus brightness of the penumbra is a natural consequence of the Evershed flow, and that magnetic flux tubes about 250 km in diameter can explain the morphology of sunspot penumbrae.

  18. The Hartree Centre's on-demand high performance computing (HPC) service, enCORE, managed by channel partners OCF, has enabled

    E-Print Network [OSTI]

    The Hartree Centre's on-demand high performance computing (HPC) service, enCORE, managed by channel that create insights and value using high performance computing, big data analytics, simulation and modelling

  19. Benchmark Evaluation of the NRAD Reactor LEU Core Startup Measurements

    SciTech Connect (OSTI)

    J. D. Bess; T. L. Maddock; M. A. Marshall

    2011-09-01

    The Neutron Radiography (NRAD) reactor is a 250-kW TRIGA-(Training, Research, Isotope Production, General Atomics)-conversion-type reactor at the Idaho National Laboratory; it is primarily used for neutron radiography analysis of irradiated and unirradiated fuels and materials. The NRAD reactor was converted from HEU to LEU fuel with 60 fuel elements and brought critical on March 31, 2010. This configuration of the NRAD reactor has been evaluated as an acceptable benchmark experiment and is available in the 2011 editions of the International Handbook of Evaluated Criticality Safety Benchmark Experiments (ICSBEP Handbook) and the International Handbook of Evaluated Reactor Physics Benchmark Experiments (IRPhEP Handbook). Significant effort went into precisely characterizing all aspects of the reactor core dimensions and material properties; detailed analyses of reactor parameters minimized experimental uncertainties. The largest contributors to the total benchmark uncertainty were the 234U, 236U, Er, and Hf content in the fuel; the manganese content in the stainless steel cladding; and the unknown level of water saturation in the graphite reflector blocks. A simplified benchmark model of the NRAD reactor was prepared with a keff of 1.0012 {+-} 0.0029 (1s). Monte Carlo calculations with MCNP5 and KENO-VI and various neutron cross section libraries were performed and compared with the benchmark eigenvalue for the 60-fuel-element core configuration; all calculated eigenvalues are between 0.3 and 0.8% greater than the benchmark value. Benchmark evaluations of the NRAD reactor are beneficial in understanding biases and uncertainties affecting criticality safety analyses of storage, handling, or transportation applications with LEU-Er-Zr-H fuel.

  20. Triggering collapse of the presolar dense cloud core and injecting short-lived radioisotopes with a shock wave. III. Rotating three-dimensional cloud cores

    SciTech Connect (OSTI)

    Boss, Alan P.; Keiser, Sandra A.

    2014-06-10

    A key test of the supernova triggering and injection hypothesis for the origin of the solar system's short-lived radioisotopes is to reproduce the inferred initial abundances of these isotopes. We present here the most detailed models to date of the shock wave triggering and injection process, where shock waves with varied properties strike fully three-dimensional, rotating, dense cloud cores. The models are calculated with the FLASH adaptive mesh hydrodynamics code. Three different outcomes can result: triggered collapse leading to fragmentation into a multiple protostar system; triggered collapse leading to a single protostar embedded in a protostellar disk; or failure to undergo dynamic collapse. Shock wave material is injected into the collapsing clouds through Rayleigh-Taylor fingers, resulting in initially inhomogeneous distributions in the protostars and protostellar disks. Cloud rotation about an axis aligned with the shock propagation direction does not increase the injection efficiency appreciably, as the shock parameters were chosen to be optimal for injection even in the absence of rotation. For a shock wave from a core-collapse supernova, the dilution factors for supernova material are in the range of ?10{sup –4} to ?3 × 10{sup –4}, in agreement with recent laboratory estimates of the required amount of dilution for {sup 60}Fe and {sup 26}Al. We conclude that a type II supernova remains as a promising candidate for synthesizing the solar system's short-lived radioisotopes shortly before their injection into the presolar cloud core by the supernova's remnant shock wave.

  1. Turbine component casting core with high resolution region

    DOE Patents [OSTI]

    Kamel, Ahmed; Merrill, Gary B.

    2014-08-26

    A hollow turbine engine component with complex internal features can include a first region and a second, high resolution region. The first region can be defined by a first ceramic core piece formed by any conventional process, such as by injection molding or transfer molding. The second region can be defined by a second ceramic core piece formed separately by a method effective to produce high resolution features, such as tomo lithographic molding. The first core piece and the second core piece can be joined by interlocking engagement that once subjected to an intermediate thermal heat treatment process thermally deform to form a three dimensional interlocking joint between the first and second core pieces by allowing thermal creep to irreversibly interlock the first and second core pieces together such that the joint becomes physically locked together providing joint stability through thermal processing.

  2. MIC-SVM: Designing A Highly Efficient Support Vector Machine For Advanced Modern Multi-Core and Many-Core Architectures

    SciTech Connect (OSTI)

    You, Yang; Song, Shuaiwen; Fu, Haohuan; Marquez, Andres; Mehri Dehanavi, Maryam; Barker, Kevin J.; Cameron, Kirk; Randles, Amanda; Yang, Guangwen

    2014-08-16

    Support Vector Machine (SVM) has been widely used in data-mining and Big Data applications as modern commercial databases start to attach an increasing importance to the analytic capabilities. In recent years, SVM was adapted to the ?eld of High Performance Computing for power/performance prediction, auto-tuning, and runtime scheduling. However, even at the risk of losing prediction accuracy due to insuf?cient runtime information, researchers can only afford to apply of?ine model training to avoid signi?cant runtime training overhead. To address the challenges above, we designed and implemented MICSVM, a highly efficient parallel SVM for x86 based multi-core and many core architectures, such as the Intel Ivy Bridge CPUs and Intel Xeon Phi coprocessor (MIC).

  3. Nuclear physics with spherically symmetric supernova models

    E-Print Network [OSTI]

    M. Liebendoerfer; T. Fischer; C. Fröhlich; F. -K. Thielemann; S. Whitehouse

    2007-08-31

    Few years ago, Boltzmann neutrino transport led to a new and reliable generation of spherically symmetric models of stellar core collapse and postbounce evolution. After the failure to prove the principles of the supernova explosion mechanism, these sophisticated models continue to illuminate the close interaction between high-density matter under extreme conditions and the transport of leptons and energy in general relativistically curved space-time. We emphasize that very different input physics is likely to be relevant for the different evolutionary phases, e.g. nuclear structure for weak rates in collapse, the equation of state of bulk nuclear matter during bounce, multidimensional plasma dynamics in the postbounce evolution, and neutrino cross sections in the explosive nucleosynthesis. We illustrate the complexity of the dynamics using preliminary 3D MHD high-resolution simulations based on parameterized deleptonization. With established spherically symmetric models we show that typical features of the different phases are reflected in the predicted neutrino signal and that a consistent neutrino flux leads to electron fractions larger than 0.5 in neutrino-driven supernova ejecta.

  4. Rapid characterization of drill core and cutting mineralogy using...

    Open Energy Info (EERE)

    characterization of drill core and cutting mineralogy using infrared spectroscopy Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: Rapid...

  5. Core Analysis At Valles Caldera - Sulphur Springs Geothermal...

    Open Energy Info (EERE)

    Core Analysis Activity Date - 1995 Usefulness could be useful with more improvements DOE-funding Unknown Exploration Basis The study utilizes the fission-track dating method...

  6. Physics-based multiscale coupling for full core nuclear reactor...

    Office of Scientific and Technical Information (OSTI)

    multiscale coupling for full core nuclear reactor simulation Numerical simulation of nuclear reactors is a key technology in the quest for improvements in efficiency, safety,...

  7. Percolation Explains How Earth's Iron Core Formed | Stanford...

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

    experimental results have ruled out percolation as a major core formation mechanism for Earth at the relatively lower pressure conditions in the upper mantle, but until now...

  8. Ultrafast Core-Hole Induced Dynamics in Water

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

    is essential for many diverse fields, from condensed matter physics to medicine to environmental science. An incoming photon with enough energy to produce a core hole in a...

  9. DOE Announces Selections for SSL Core Technology Research (Round...

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

    of SSL technologies, creating jobs, and promoting America's role as a global leader in energy efficiency. The six selections that fall under Core Technology and Product...

  10. DOE Announces Selections for Solid-State Lighting Core Technology...

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

    Core Technology and Product Development Funding Opportunities (Round 3) The National Energy Technology Laboratory (NETL), on behalf of the U.S. Department of Energy (DOE), is...

  11. CSAT Role-Based/Core Competency Training Program | Department...

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

    Core Competency Training Program The DOE OCIO has developed role-basedcore competency training modules for DOE Cybersecurity staff and other employees fulfilling significant...

  12. Do Core Sample Measurements Record Group or Phase Velocity?

    E-Print Network [OSTI]

    Joe Dellinger, Univ. of Hawaii, Lev Vernik, Stanford Univ.

    2001-08-12

    Laboratory core-sample measurements do not record elas- ..... appear in GEOPHYSICS. ... extreme cases they may measure something hard to interpret.

  13. Mineral Deformation at Earth's Core-Mantle Boundary

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

    At the core-mantle boundary (CMB), 2900 km deep, seismologists have discovered that seismic waves travel faster in certain directions. This seismic anisotropy appears to be...

  14. CONTRIBUTION OF GAMMA-RAY-LOUD RADIO GALAXIES' CORE EMISSIONS...

    Office of Scientific and Technical Information (OSTI)

    The Fermi gamma-ray satellite has recently detected gamma-ray emissions from radio galaxy cores. From these samples, we first examine the correlation between the luminosities...

  15. Core excitation effects in the breakup of halo nuclei

    SciTech Connect (OSTI)

    Moro, A. M.; Diego, R. de; Lay, J. A.; Crespo, R.; Johnson, R. C.; Arias, J. M.; Gomez-Camacho, J.

    2012-10-20

    The role of core excitation in the structure and dynamics of two-body halo nuclei is investigated. We present calculations for the resonant breakup of {sup 11}Be on protons at an incident energy of 63.7 MeV/nucleon, where core excitation effects were shown to be important. To describe the reaction, we use a recently developed extension of the DWBA formalism which incorporates these core excitation effects within the no-recoil approximation. The validity of the no-recoil approximation is also examined by comparing with DWBA calculations which take into account core recoil. In addition, calculations with two different continuum representations are presented and compared.

  16. Predictions for microlensing planetary events from core accretion theory

    SciTech Connect (OSTI)

    Zhu, Wei; Mao, Shude [National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100012 (China); Penny, Matthew; Gould, Andrew [Department of Astronomy, The Ohio State University, 140 W. 18th Avenue, Columbus, OH 43210 (United States); Gendron, Rieul, E-mail: weizhu@astronomy.ohio-state.edu [Jodrell Bank Centre for Astrophysics, University of Manchester, Alan Turing Building, Manchester M13 9PL (United Kingdom)

    2014-06-10

    We conduct the first microlensing simulation in the context of a planet formation model. The planet population is taken from the Ida and Lin core accretion model for 0.3 M {sub ?} stars. With 6690 microlensing events, we find that for a simplified Korea Microlensing Telescopes Network (KMTNet), the fraction of planetary events is 2.9%, out of which 5.5% show multiple-planet signatures. The numbers of super-Earths, super-Neptunes, and super-Jupiters detected are expected to be almost equal. Our simulation shows that high-magnification events and massive planets are favored by planet detections, which is consistent with previous expectation. However, we notice that extremely high-magnification events are less sensitive to planets, which is possibly because the 10 minute sampling of KMTNet is not intensive enough to capture the subtle anomalies that occur near the peak. This suggests that while KMTNet observations can be systematically analyzed without reference to any follow-up data, follow-up observations will be essential in extracting the full science potential of very high magnification events. The uniformly high-cadence observations expected for KMTNet also result in ?55% of all detected planets not being caustic crossing, and more low-mass planets even down to Mars mass being detected via planetary caustics. We also find that the distributions of orbital inclinations and planet mass ratios in multiple-planet events agree with the intrinsic distributions.

  17. Core-Shell Diamond as a Support for Solid-Phase Extraction and High-Performance Liquid Chromatography

    SciTech Connect (OSTI)

    Saini, Gaurav; Jensen, David S.; Wiest, Landon A.; Vail, Michael A.; Dadson, Andrew; Lee, Milton L.; Shutthanandan, V.; Linford, Matthew R.

    2010-06-01

    We report the formation of core-shell diamond particles for solid phase extraction (SPE) and high performance liquid chromatography (HPLC) made by layer-by-layer (LbL) deposition. Their synthesis begins with the amine functionalization of microdiamond by its immersion in an aqueous solution of a primary amine-containing polymer (polyallylamine (PAAm)). The amine-terminated microdiamond is then immersed in an aqueous suspension of nanodiamond, which leads to adsorption of the nanodiamond. Alternating (self-limiting) immersions in the solutions of the amine-containing polymer and the suspension of nanodiamond are continued until the desired number of nanodiamond layers is formed around the microdiamond. Finally, the core-shell particles are cross-linked with 1,2,5,6-diepoxycyclooctane or reacted with 1,2-epoxyoctadecane. Layer-by-layer deposition of PAAm and nanodiamond is also studied on planar Si/SiO2 surfaces, which were characterized by SEM, Rutherford backscattering spectrometry (RBS) and nuclear reaction analysis (NRA). Core-shell particles are characterized by diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), environmental scanning electron microscopy (ESEM), and Brunauer Emmett Teller (BET) surface area and pore size measurements. Larger (ca. 50 ?m) core-shell diamond particles have much higher surface areas, and analyte loading capacities in SPE than nonporous solid diamond particles. Smaller (ca. 3 ?m), normal and reversed phase, core-shell diamond particles have been used for HPLC, with 36,300 plates per meter for mesitylene in a separation of benzene and alkyl benzenes on a C18 adsorbent, and 54,800 plates per meter for diazinon in a similar separation of two pesticides.

  18. Multi-model Mean Nitrogen and Sulfur Deposition from the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP): Evaluation of Historical and Projected Future Changes

    SciTech Connect (OSTI)

    Lamarque, Jean-Francois; Dentener, Frank; McConnell, J.R.; Ro, C-U; Shaw, Mark; Vet, Robert; Bergmann, D.; Cameron-Smith, Philip; Dalsoren, S.; Doherty, R.; Faluvegi, G.; Ghan, Steven J.; Josse, B.; Lee, Y. H.; MacKenzie, I. A.; Plummer, David; Shindell, Drew; Skeie, R. B.; Stevenson, D. S.; Strode, S.; Zeng, G.; Curran, M.; Dahl-Jensen, D.; Das, S.; Fritzsche, D.; Nolan, M.

    2013-08-20

    We present multi-model global datasets of nitrogen and sulfate deposition covering time periods from 1850 to 2100, calculated within the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP). The computed deposition fluxes are compared to surface wet deposition and ice-core measurements. We use a new dataset of wet deposition for 2000-2002 based on critical assessment of the quality of existing regional network data. We show that for present-day (year 2000 ACCMIP time-slice), the ACCMIP results perform similarly to previously published multi-model assessments. The analysis of changes between 1980 and 2000 indicates significant differences between model and measurements over the United States, but less so over Europe. This difference points towards misrepresentation of 1980 NH3 emissions over North America. Based on ice-core records, the 1850 deposition fluxes agree well with Greenland ice cores but the change between 1850 and 2000 seems to be overestimated in the Northern Hemisphere for both nitrogen and sulfur species. Using the Representative Concentration Pathways to define the projected climate and atmospheric chemistry related emissions and concentrations, we find large regional nitrogen deposition increases in 2100 in Latin America, Africa and parts of Asia under some of the scenarios considered. Increases in South Asia are especially large, and are seen in all scenarios, with 2100 values more than double 2000 in some scenarios and reaching >1300 mgN/m2/yr averaged over regional to continental scale regions in RCP 2.6 and 8.5, ~30-50% larger than the values in any region currently (2000). Despite known issues, the new ACCMIP deposition dataset provides novel, consistent and evaluated global gridded deposition fields for use in a wide range of climate and ecological studies.

  19. Assessment of RELAP5/MOD3.1 for gravity-driven injection experiment in the core makeup tank of the CARR Passive Reactor (CP-1300)

    SciTech Connect (OSTI)

    Lee, S.I.; No, H.C.; Bang, Y.S.; Kim, H.J.

    1996-10-01

    The objective of the present work is to improve the analysis capability of RELAP5/MOD3.1 on the direct contact condensation in the core makeup tank (CMT) of passive high-pressure injection system (PHPIS) in the CARR Passive Reactor (CP-1300). The gravity-driven injection experiment is conducted by using a small scale test facility to identify the parameters having significant effects on the gravity-driven injection and the major condensation modes. It turns out that the larger the water subcooling is, the more initiation of injection is delayed, and the sparger and the natural circulation of the hot water from the steam generator accelerate the gravity-driven injection. The condensation modes are divided into three modes: sonic jet, subsonic jet, and steam cavity. RELAP5/MOD3.1 is chosen to evaluate the cod predictability on the direct contact condensation in the CMT. It is found that the predictions of MOD3.1 are in better agreement with the experimental data than those of MOD3.0. From the nodalization study of the test section, the 1-node model shows better agreement with the experimental data than the multi-node models. RELAP5/MOD3.1 identifies the flow regime of the test section as vertical stratification. However, the flow regime observed in the experiment is the subsonic jet with the bubble having the vertical cone shape. To accurately predict the direct contact condensation in the CMT with RELAP5/MOD3.1, it is essential that a new set of the interfacial heat transfer coefficients and a new flow regime map for direct contact condensation in the CMT be developed.

  20. Behavior of core debris ejected from a pressurized vessel into scaled reactor cavities

    SciTech Connect (OSTI)

    Tarbell, W.W.; Pilch, M.; Brockmann, J.E.

    1984-01-01

    Results from four recent 1:10 scale experiments are presented along with analyses of the possible consequences for plant geometries. The tests cover a range in initial system pressure from 4 to 12 MPa, with either dry or water-filled cavities. Nearly all of the core debris is dispersed from the cavity with less than five percent (5%) of the original mass found adhered to the exposed cavity surfaces. Those tests involving water in the cavity show the water being expelled as a slug ahead of the dispersed melt. Models for the interaction of the ejected core debris with the containment atmosphere show that both thermal and chemical energy is liberated from the debris. The calculated pressurization from direct heating of the containment atmosphere can threaten even the most robust containments. Models and experiments are currently being devised to study the possible mitigating effects of the above-cavity structures.

  1. Evaluating Multi-core Architectures through Accelerating the Three-Dimensional Lax–Wendroff Correction

    SciTech Connect (OSTI)

    You, Yang; Fu, Haohuan; Song, Shuaiwen; Mehri Dehanavi, Maryam; Gan, Lin; Huang, Xiaomeng; Yang, Guangwen

    2014-07-18

    Wave propagation forward modeling is a widely used computational method in oil and gas exploration. The iterative stencil loops in such problems have broad applications in scientific computing. However, executing such loops can be highly time time-consuming, which greatly limits application’s performance and power efficiency. In this paper, we accelerate the forward modeling technique on the latest multi-core and many-core architectures such as Intel Sandy Bridge CPUs, NVIDIA Fermi C2070 GPU, NVIDIA Kepler K20x GPU, and the Intel Xeon Phi Co-processor. For the GPU platforms, we propose two parallel strategies to explore the performance optimization opportunities for our stencil kernels. For Sandy Bridge CPUs and MIC, we also employ various optimization techniques in order to achieve the best.

  2. ACHILLES: Heat Transfer in PWR Core During LOCA Reflood Phase

    SciTech Connect (OSTI)

    2013-11-01

    1. NAME AND TITLE OF DATA LIBRARY ACHILLES -Heat Transfer in PWR Core During LOCA Reflood Phase. 2. NAME AND TITLE OF DATA RETRIEVAL PROGRAMS N/A 3. CONTRIBUTOR AEA Technology, Winfrith Technology Centre, Dorchester DT2 8DH United Kingdom through the OECD Nuclear Energy Agency Data Bank, Issy-les-Moulineaux, France. 4. DESCRIPTION OF TEST FACILITY The most important features of the Achilles rig were the shroud vessel, which contained the test section, and the downcomer. These may be thought of as representing the core barrel and the annular downcomer in the reactor pressure vessel. The test section comprises a cluster of 69 rods in a square array within a circular shroud vessel. The rod diameter and pitch (9.5 mm and 12.6 mm) were typical of PWR dimensions. The internal diameter of the shroud vessel was 128 mm. Each rod was electrically heated over a length of 3.66 m, which is typical of the nuclear heated length in a PWR fuel rod, and each contained 6 internal thermocouples. These were arranged in one of 8 groupings which concentrated the thermocouples in different axial zones. The spacer grids were at prototypic PWR locations. Each grid had two thermocouples attached to its trailing edge at radial locations. The axial power profile along the rods was an 11 step approximation to a "chopped cosine". The shroud vessel had 5 heating zones whose power could be independently controlled. 5. DESCRIPTION OF TESTS The Achilles experiments investigated the heat transfer in the core of a Pressurized Water Reactor during the re-flood phase of a postulated large break loss of coolant accident. The results provided data to validate codes and to improve modeling. Different types of experiments were carried out which included single phase cooling, re-flood under low flow conditions, level swell and re-flood under high flow conditions. Three series of experiments were performed. The first and the third used the same test section but the second used another test section, similar in all respects except that it contained a partial blockage formed by attaching sleeves (or "balloons") to some of the rods. 6. SOURCE AND SCOPE OF DATA Phenomena Tested - Heat transfer in the core of a PWR during a re-flood phase of postulated large break LOCA. Test Designation - Achilles Rig. The programme includes the following types of experiments: - on an unballooned cluster: -- single phase air flow -- low pressure level swell -- low flooding rate re-flood -- high flooding rate re-flood - on a ballooned cluster containing 80% blockage formed by 16 balloon sleeves -- single phase air flow -- low flooding rate re-flood 7. DISCUSSION OF THE DATA RETRIEVAL PROGRAM N/A 8. DATA FORMAT AND COMPUTER Many Computers (M00019MNYCP00). 9. TYPICAL RUNNING TIME N/A 11. CONTENTS OF LIBRARY The ACHILLES package contains test data and associated data processing software as well as the documentation listed above. 12. DATE OF ABSTRACT November 2013. KEYWORDS: DATABASES, BENCHMARKS, HEAT TRANSFER, LOSS-OF-COLLANT ACCIDENT, PWR REACTORS, REFLOODING

  3. Advanced Core Design And Fuel Management For Pebble-Bed Reactors

    SciTech Connect (OSTI)

    Hans D. Gougar; Abderrafi M. Ougouag; William K. Terry

    2004-10-01

    A method for designing and optimizing recirculating pebble-bed reactor cores is presented. At the heart of the method is a new reactor physics computer code, PEBBED, which accurately and efficiently computes the neutronic and material properties of the asymptotic (equilibrium) fuel cycle. This core state is shown to be unique for a given core geometry, power level, discharge burnup, and fuel circulation policy. Fuel circulation in the pebble-bed can be described in terms of a few well?defined parameters and expressed as a recirculation matrix. The implementation of a few heat?transfer relations suitable for high-temperature gas-cooled reactors allows for the rapid estimation of thermal properties critical for safe operation. Thus, modeling and design optimization of a given pebble-bed core can be performed quickly and efficiently via the manipulation of a limited number key parameters. Automation of the optimization process is achieved by manipulation of these parameters using a genetic algorithm. The end result is an economical, passively safe, proliferation-resistant nuclear power plant.

  4. Spectroscopic determination of temperature and density spatial profiles and mix in indirect-drive implosion cores

    SciTech Connect (OSTI)

    Welser-Sherrill, L.; Mancini, R. C. [Department of Physics, University of Nevada, Reno, Nevada 89557 (United States); Koch, J. A.; Izumi, N.; Tommasini, R.; Haan, S. W. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Haynes, D. A.; Kyrala, G. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Golovkin, I. E.; MacFarlane, J. J. [Prism Computational Sciences, Madison, Wisconsin 53703 (United States); Delettrez, J. A.; Marshall, F. J.; Regan, S. P.; Smalyuk, V. A. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States)

    2007-11-15

    In the field of inertial confinement fusion (ICF), work has been consistently progressing in the past decade toward a more fundamental understanding of the plasma conditions in ICF implosion cores. The research presented here represents a substantial evolution in the ability to diagnose plasma temperatures and densities, along with characteristics of mixing between fuel and shell materials. Mixing is a vital property to study and quantify, since it can significantly affect implosion quality. We employ a number of new spectroscopic techniques that allow us to probe these important quantities. The first technique developed is an emissivity analysis, which uses the emissivity ratio of the optically thin Ly{beta} and He{beta} lines to spectroscopically extract temperature profiles, followed by the solution of emissivity equations to infer density profiles. The second technique, an intensity analysis, models the radiation transport through the implosion core. The nature of the intensity analysis allows us to use an optically thick line, the Ly{alpha}, to extract information on mixing near the core edge. With this work, it is now possible to extract directly from experimental data not only detailed temperature and density maps of the core, but also spatial mixing profiles.

  5. CO2 flood tests on whole core samples of the Mt. Simon sandstone, Illinois Basin

    SciTech Connect (OSTI)

    O'Connor, William K.; Rush, Gilbert E.

    2005-09-01

    Geological sequestration of CO2, whether by enhanced oil recovery (EOR), coal-bed methane (CBM) recovery, or saline aquifer injection is a promising near-term sequestration methodology. While tremendous experience exists for EOR, and CBM recovery has been demonstrated in existing fields, saline aquifer injection studies have only recently been initiated. Studies evaluating the availability of saline aquifers suitable for CO2 injection show great potential, however, the long-term fate of the CO2 injected into these ancient aqueous systems is still uncertain. For the subject study, a series of laboratory-scale CO2 flood tests were conducted on whole core samples of the Mt. Simon sandstone from the Illinois Basin. By conducting these tests on whole core samples rather than crushed core, an evaluation of the impact of the CO2 flood on the rock mechanics properties as well as the geochemistry of the core and brine solution has been possible. This empirical data could provide a valuable resource for the validation of reservoir models under development for these engineered CO2 systems.

  6. Comparison of prestellar core elongations and large-scale molecular cloud structures in the Lupus I region

    SciTech Connect (OSTI)

    Poidevin, Frédérick; Ade, Peter A. R.; Hargrave, Peter C.; Nutter, David; Angile, Francesco E.; Devlin, Mark J.; Klein, Jeffrey; Benton, Steven J.; Netterfield, Calvin B.; Chapin, Edward L.; Fissel, Laura M.; Gandilo, Natalie N.; Fukui, Yasuo; Gundersen, Joshua O.; Korotkov, Andrei L.; Matthews, Tristan G.; Novak, Giles; Moncelsi, Lorenzo; Mroczkowski, Tony K.; Olmi, Luca; and others

    2014-08-10

    Turbulence and magnetic fields are expected to be important for regulating molecular cloud formation and evolution. However, their effects on sub-parsec to 100 parsec scales, leading to the formation of starless cores, are not well understood. We investigate the prestellar core structure morphologies obtained from analysis of the Herschel-SPIRE 350 ?m maps of the Lupus I cloud. This distribution is first compared on a statistical basis to the large-scale shape of the main filament. We find the distribution of the elongation position angle of the cores to be consistent with a random distribution, which means no specific orientation of the morphology of the cores is observed with respect to the mean orientation of the large-scale filament in Lupus I, nor relative to a large-scale bent filament model. This distribution is also compared to the mean orientation of the large-scale magnetic fields probed at 350 ?m with the Balloon-borne Large Aperture Telescope for Polarimetry during its 2010 campaign. Here again we do not find any correlation between the core morphology distribution and the average orientation of the magnetic fields on parsec scales. Our main conclusion is that the local filament dynamics—including secondary filaments that often run orthogonally to the primary filament—and possibly small-scale variations in the local magnetic field direction, could be the dominant factors for explaining the final orientation of each core.

  7. Simulating Astro-E2 Observations of Galaxy Clusters: the Case of Turbulent Cores Affected by Tsunamis

    E-Print Network [OSTI]

    Yutaka Fujita; Tomoaki Matsumoto; Keiichi Wada; Tae Furusho

    2004-12-14

    This is the first attempt to construct detailed X-ray spectra of clusters of galaxies from the results of high-resolution hydrodynamic simulations and simulate X-ray observations in order to study velocity fields of the intracluster medium (ICM). The hydrodynamic simulations are based on the recently proposed tsunami model, in which cluster cores are affected by bulk motions of the ICM and turbulence is produced. We note that most other solutions of the cooling flow problem also involve the generation of turbulence in cluster cores. From the mock X-ray observations with Astro-E2 XRS, we find that turbulent motion of the ICM in cluster cores could be detected with the satellite. The Doppler shifts of the metal lines could be used to discriminate among turbulence models. The gas velocities measured through the mock observations are consistent with the line-emission weighted values inferred directly from hydrodynamic simulations.

  8. Casting an Object with a Core Hee-Kap Ahn

    E-Print Network [OSTI]

    Cheng, Siu-Wing

    Casting an Object with a Core Hee-Kap Ahn Sang Won Bae Siu-Wing Cheng Kyung-Yong Chwa Abstract This paper addresses geometric problems that concern manufacturing an object using a cast with a core. In casting, molten material is poured into the cavity of the cast and allowed to solidify. The cast has two

  9. Tame structures and open cores Version 3.2

    E-Print Network [OSTI]

    Fornasiero, Antongiulio

    Tame structures and open cores Version 3.2 A. Fornasiero March 18, 2010 Abstract We study various notions of "tameness" for definably complete expan- sions of ordered fields. We mainly study structures with locally o-minimal open core, d-minimal structures, and dense pairs of d-minimal structures. Key words: o

  10. Compiler Control Power Saving Scheme for Multi Core Processors

    E-Print Network [OSTI]

    Kasahara, Hironori

    Compiler Control Power Saving Scheme for Multi Core Processors Jun shirako , Naoto Oshiyama. To this end, the compiler for a multi core processor is expected not only to parallelize program effectively an application program. This paper proposes a compilation scheme for reduction of power consumption under

  11. Interdisciplinary Institute for Innovation How did Fukushima-Daiichi core

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Interdisciplinary Institute for Innovation How did Fukushima-Daiichi core meltdown change@mines-paristech.fr hal-00740684,version1-10Oct2012 #12;How did Fukushima-Daiichi core meltdown change the probability the probability of a nuclear accident using past observations? What increase in probability the Fukushima Dai

  12. Scaling an RNS number using the core function Neil Burgess,

    E-Print Network [OSTI]

    Oklobdzija, Vojin G.

    Scaling an RNS number using the core function Neil Burgess, Cardiff School of Engineering, Cardiff for extracting the core of a Residue Number System (RNS) number within the RNS, this affording a new method for scaling RNS numbers. Suppose an RNS comprises a set of co-prime moduli, mi, with mi = M. This paper

  13. UNCERTAINTY IN PALEOECOLOGICAL STUDIES OF MERCURY IN SEDIMENT CORES

    E-Print Network [OSTI]

    Gottgens, Hans

    UNCERTAINTY IN PALEOECOLOGICAL STUDIES OF MERCURY IN SEDIMENT CORES JOHAN F. GOTTGENS1,, BRIAN E by as much as ±48%. Uncertainty in paleoecological studies of mercury needs to be documented in order, paleoecology, sediment cores, uncertainty 1. Introduction Paleoecological studies of lakes, wetlands

  14. THE PHYSICS OF CORE COLLAPSE Eliza McDonald

    E-Print Network [OSTI]

    Budker, Dmitry

    of two main types of supernova Caused as stars collapse in on themselves as fusion stops Leaves behind M Star #12;CORE COLLAPSE Fusion stops after Iron, leaving an inert core After Chandrasekhar mass 2005 #12;CONCLUSIONS Stars are held up by pressure from nuclear fusion, and fall in when that fusion

  15. INTEGRATING HARDWARE EXPERIENCES INTO A COMPUTER ARCHITECTURE CORE COURSE

    E-Print Network [OSTI]

    INTEGRATING HARDWARE EXPERIENCES INTO A COMPUTER ARCHITECTURE CORE COURSE Fred G. Martin University@cs.uml.edu ABSTRACT A core curriculum computer architecture course is designed with a significant hardware component on their own PC. The lab kit supports introductory, hardware-based activities in digital logic

  16. Star cell type core configuration for structural sandwich materials

    DOE Patents [OSTI]

    Christensen, Richard M. (Danville, CA)

    1995-01-01

    A new pattern for cellular core material used in sandwich type structural materials. The new pattern involves star shaped cells intermixed with hexagonal shaped cells. The new patterned cellular core material includes star shaped cells interconnected at points thereof and having hexagonal shape cells positioned adjacent the star points. The new pattern allows more flexibility and can conform more easily to curved shapes.

  17. Core Mathematics Honors College of Science MATH-BS

    E-Print Network [OSTI]

    Kihara, Daisuke

    Core Mathematics Honors College of Science MATH-BS Code-MAHO Departmental/Program Major Courses (76 Of Analysis or MA 44000 Real Analysis Honors (3) MA 35300 Linear Algebra II With Applications (3) Math ******************************************************************************************************************************** #12;Revised 2/2013 (effective Fall 2013) Core Mathematics Honors http://www.math

  18. Core Mathematics College of Science MATH-BS

    E-Print Network [OSTI]

    Kihara, Daisuke

    Core Mathematics College of Science MATH-BS Code-MATH Departmental/Program Major Courses (77 II With Applications (3) Math Selective I: MA 36200 Topics In Vector Calculus/MA 44200 - Multivariate ******************************************************************************************************************************** #12;Revised 2/2013 (effective Fall 2013) Core Mathematics http://www.math

  19. Tsunami: Massively Parallel Homomorphic Hashing on Many-core GPUs

    E-Print Network [OSTI]

    Li, Zongpeng

    1 Tsunami: Massively Parallel Homomorphic Hashing on Many-core GPUs Xiaowen Chu Department. In this paper, we present a massively parallel solution, named Tsunami, by exploiting the widely available many-core Graphic Processing Units (GPUs). Tsunami includes the following optimization techniques to achieve

  20. Solid oxide fuel cell with monolithic core

    DOE Patents [OSTI]

    McPheeters, C.C.; Mrazek, F.C.

    1988-08-02

    A solid oxide fuel cell in which fuel and oxidant gases undergo an electrochemical reaction to produce an electrical output includes a monolithic core comprised of a corrugated conductive sheet disposed between upper and lower generally flat sheets. The corrugated sheet includes a plurality of spaced, parallel, elongated slots which form a series of closed, linear, first upper and second lower gas flow channels with the upper and lower sheets within which a fuel gas and an oxidant gas respectively flow. Facing ends of the fuel cell are generally V-shaped and provide for fuel and oxidant gas inlet and outlet flow, respectively, and include inlet and outlet gas flow channels which are continuous with the aforementioned upper fuel gas and lower oxidant gas flow channels. The upper and lower flat sheets and the intermediate corrugated sheet are preferably comprised of ceramic materials and are securely coupled together such as by assembly in the green state and sintering together during firing at high temperatures. A potential difference across the fuel cell, or across a stacked array of similar fuel cells, is generated when an oxidant gas such as air and a fuel such as hydrogen gas is directed through the fuel cell at high temperatures, e.g., between 700 C and 1,100 C. 8 figs.

  1. Solid oxide fuel cell with monolithic core

    DOE Patents [OSTI]

    McPheeters, Charles C. (Plainfield, IL); Mrazek, Franklin C. (Hickory Hills, IL)

    1988-01-01

    A solid oxide fuel cell in which fuel and oxidant gases undergo an electrochemical reaction to produce an electrical output includes a monolithic core comprised of a corrugated conductive sheet disposed between upper and lower generally flat sheets. The corrugated sheet includes a plurality of spaced, parallel, elongated slots which form a series of closed, linear, first upper and second lower gas flow channels with the upper and lower sheets within which a fuel gas and an oxidant gas respectively flow. Facing ends of the fuel cell are generally V-shaped and provide for fuel and oxidant gas inlet and outlet flow, respectively, and include inlet and outlet gas flow channels which are continuous with the aforementioned upper fuel gas and lower oxidant gas flow channels. The upper and lower flat sheets and the intermediate corrugated sheet are preferably comprised of ceramic materials and are securely coupled together such as by assembly in the green state and sintering together during firing at high temperatures. A potential difference across the fuel cell, or across a stacked array of similar fuel cells, is generated when an oxidant gas such as air and a fuel such as hydrogen gas is directed through the fuel cell at high temperatures, e.g., between 700.degree. C. and 1100.degree. C.

  2. A STUDY ON THE INCAPACITATION MECHANISM MODEL OF THE JUCHIST AND MARXIST-LENINIST ARTICLES AGAINST THE CORE IMPLEMENTATION MECHANISM MODEL OF THE FUNDAMENTAL RIGHTS ARTICLES IN THE NORTH KOREAN CONSTITUTION: NORTH KOREA'S VIOLATIONS OF FUNDAMENTAL RIGHTS AND INTERNATIONAL HUMAN RIGHTS TREATIES

    E-Print Network [OSTI]

    Jun, Woo-Suk

    2014-05-31

    OF FUNDAMENTAL RIGHTS AND INTERNATIONAL HUMAN RIGHTS TREATIES By Woo-Suk Jun Submitted to the School of Law, University of Kansas in partial fulfillment of the requirements for the degree of Doctor of Juridical Science (S...) _________________________________________ Professor Elizabeth S. Cateforis (Member) Date Defended: March 13, 2014 ii The Dissertation Committee for Woo-Suk Jun certifies that this is the approved version of the following dissertation: A STUDY ON THE INCAPACITATION MECHANISM MODEL...

  3. Vector spectropolarimetry of dark-cored penumbral filaments with Hinode

    E-Print Network [OSTI]

    L. R. Bellot Rubio; S. Tsuneta; K. Ichimoto; Y. Katsukawa; B. W. Lites; S. Nagata; T. Shimizu; R. A. Shine; Y. Suematsu; T. D. Tarbell; A. M. Title; J. C. del Toro Iniesta

    2007-08-21

    We present spectropolarimetric measurements of dark-cored penumbral filaments taken with Hinode at a resolution of 0.3". Our observations demonstrate that dark-cored filaments are more prominent in polarized light than in continuum intensity. Far from disk center, the Stokes profiles emerging from these structures are very asymmetric and show evidence for magnetic fields of different inclinations along the line of sight, together with strong Evershed flows of at least 6-7 km/s. In sunspots closer to disk center, dark-cored penumbral filaments exhibit regular Stokes profiles with little asymmetries due to the vanishing line-of-sight component of the horizontal Evershed flow. An inversion of the observed spectra indicates that the magnetic field is weaker and more inclined in the dark cores as compared with the surrounding bright structures. This is compatible with the idea that dark-cored filaments are the manifestation of flux tubes carrying hot Evershed flows.

  4. Process to make core-shell structured nanoparticles

    DOE Patents [OSTI]

    Luhrs, Claudia; Phillips, Jonathan; Richard, Monique N

    2014-01-07

    Disclosed is a process for making a composite material that contains core-shell structured nanoparticles. The process includes providing a precursor in the form of a powder a liquid and/or a vapor of a liquid that contains a core material and a shell material, and suspending the precursor in an aerosol gas to produce an aerosol containing the precursor. In addition, the process includes providing a plasma that has a hot zone and passing the aerosol through the hot zone of the plasma. As the aerosol passes through the hot zone of the plasma, at least part of the core material and at least part of the shell material in the aerosol is vaporized. Vapor that contains the core material and the shell material that has been vaporized is removed from the hot zone of the plasma and allowed to condense into core-shell structured nanoparticles.

  5. The Aquila prestellar core population revealed by Herschel

    E-Print Network [OSTI]

    Könyves, V; Men'shchikov, A; Schneider, N; Arzoumanian, D; Bontemps, S; Attard, M; Motte, F; Didelon, P; Maury, A; Abergel, A; Ali, B; Baluteau, J -P; Bernard, J -Ph; Cambrésy, L; Cox, P; Di Francesco, J; di Giorgio, A M; Griffin, M J; Hargrave, P; Huang, M; Kirk, J; Li, J Z; Martin, P; Minier, V; Molinari, S; Olofsson, G; Pezzuto, S; Russeil, D; Roussel, H; Saraceno, P; Sauvage, M; Sibthorpe, B; Spinoglio, L; Testi, L; Ward-Thompson, D; White, G; Wilson, C D; Woodcraft, A; Zavagno, A

    2010-01-01

    The origin and possible universality of the stellar initial mass function (IMF) is a major issue in astrophysics. One of the main objectives of the Herschel Gould Belt Survey is to clarify the link between the prestellar core mass function (CMF) and the IMF. We present and discuss the core mass function derived from Herschel data for the large population of prestellar cores discovered with SPIRE and PACS in the Aquila Rift cloud complex at d ~ 260 pc. We detect a total of 541 starless cores in the entire ~11 deg^2 area of the field imaged at 70-500 micron with SPIRE/PACS. Most of these cores appear to be gravitationally bound, and thus prestellar in nature. Our Herschel results confirm that the shape of the prestellar CMF resembles the stellar IMF, with much higher quality statistics than earlier submillimeter continuum ground-based surveys.

  6. Non-linear transformer modeling and simulation

    SciTech Connect (OSTI)

    Archer, W.E.; Deveney, M.F.; Nagel, R.L.

    1994-08-01

    Transformers models for simulation with Pspice and Analogy`s Saber are being developed using experimental B-H Loop and network analyzer measurements. The models are evaluated for accuracy and convergence using several test circuits. Results are presented which demonstrate the effects on circuit performance from magnetic core losses eddy currents and mechanical stress on the magnetic cores.

  7. Co-electrospinning fabrication and photocatalytic performance of TiO{sub 2}/SiO{sub 2} core/sheath nanofibers with tunable sheath thickness

    SciTech Connect (OSTI)

    Cao, Houbao Du, Pingfan; Song, Lixin; Xiong, Jie Yang, Junjie; Xing, Tonghai; Liu, Xin; Wu, Rongrong; Wang, Minchao; Shao, Xiaoli

    2013-11-15

    Graphical abstract: - Highlights: • The core–sheath TiO{sub 2}/SiO{sub 2} nanofibers were fabricated by co-electrospinning technique. • The catalytic property of nanofibers with different sheath thickness was studied. • The potential methods of improving catalytic efficiency are suggested. - Abstract: In this paper, core/sheath TiO{sub 2}/SiO{sub 2} nanofibers with tunable sheath thickness were directly fabricated via a facile co-electrospinning technique with subsequent calcination at 500 °C. The morphologies and structures of core/sheath TiO{sub 2}/SiO{sub 2} nanofibers were characterized by TGA, FESEM, TEM, FTIR, XPS and BET. It was found that the 1D core/sheath nanofibers are made up of anatase–rutile TiO{sub 2} core and amorphous SiO{sub 2} sheath. The influences of SiO{sub 2} sheath and its thickness on the photoreactivity were evaluated by observing photo-degradation of methylene blue aqueous solution under the irradiation of UV light. Compared with pure TiO{sub 2} nanofibers, the core/sheath TiO{sub 2}/SiO{sub 2} nanofibers performed a better catalytic performance. That was attributed to not only efficient separation of hole–electron pairs resulting from the formation of heterojunction but also larger surface area and surface silanol group which will be useful to provide higher capacity for oxygen adsorption to generate more hydroxyl radicals. And the optimized core/sheath TiO{sub 2}/SiO{sub 2} nanofibers with a sheath thickness of 37 nm exhibited the best photocatalytic performance.

  8. Pre-conceptual design study of ASTRID core

    SciTech Connect (OSTI)

    Varaine, F.; Marsault, P.; Chenaud, M. S.; Bernardin, B.; Conti, A.; Sciora, P.; Venard, C.; Fontaine, B.; Devictor, N.; Martin, L.; Scholer, A. C.; Verrier, D.

    2012-07-01

    In the framework of the ASTRID project at CEA, core design studies are performed at CEA with the AREVA and EDF support. At the stage of the project, pre-conceptual design studies are conducted in accordance with GEN IV reactors criteria, in particularly for safety improvements. An improved safety for a sodium cooled reactor requires revisiting many aspects of the design and is a rather lengthy process in current design approach. Two types of cores are under evaluation, one classical derived from the SFR V2B and one more challenging called CFV (low void effect core) with a large gain on the sodium void effect. The SFR V2b core have the following specifications: a very low burn-up reactivity swing (due to a small cycle reactivity loss) and a reduced sodium void effect with regard to past designs such as the EFR (around 2$ minus). Its performances are an average burn-up of 100 GWd/t, and an internal conversion ratio equal to one given a very good behavior of this core during a control rod withdrawal transient). The CFV with its specific design offers a negative sodium void worth while maintaining core performances. In accordance of ASTRID needs for demonstration those cores are 1500 MWth power (600 MWe). This paper will focus on the CFV pre-conceptual design of the core and S/A, and the performances in terms of safety will be evaluated on different transient scenario like ULOF, in order to assess its intrinsic behavior compared to a more classical design like V2B core. The gap in term of margin to a severe accident due to a loss of flow initiator underlines the potential capability of this type of core to enhance prevention of severe accident in accordance to safety demonstration. (authors)

  9. FY13 Annual Progress Report for SECA Core Technology Program

    SciTech Connect (OSTI)

    Stevenson, Jeffry W.; Koeppel, Brian J.

    2014-01-31

    This progress report covers technical work performed during fiscal year 2013 at PNNL under Field Work Proposal (FWP) 40552. The report highlights and documents technical progress in tasks related to advanced cell and stack component materials development and computational design and simulation. Primary areas of emphasis for the materials development work were metallic interconnects and coatings, cathode and anode stability/degradation, glass seals, and advanced testing under realistic stack conditions: Metallic interconnects and coatings • Effects of surface modifications to AISI 441 (prior to application of protective spinel coatings) on oxide scale growth and adhesion were evaluated as a function of temperature and time. Cathode stability/degradation • Effects of cathode air humidity on performance and stability of SOFC cathodes were investigated by testing anode-supported cells as a function of time and temperature. • In-situ high temperature XRD measurements were used to correlate changes in cathode lattice structure and composition with performance of anode-supported button cells. Anode stability/degradation • Effects of high fuel steam content on Ni/YSZ anodes were investigated over a range of time and temperature. • Vapor infiltration and particulate additions were evaluated as a potential means of improving tolerance of Ni/YSZ anodes to sulfur-bearing fuel species. Glass seals • A candidate compliant glass-based seal materials were evaluated in terms of microstructural evolution and seal performance as a function of time and temperature. Stack fixture testing • The SECA CTP stack test fixture was used for intermediate and long-term evaluation of candidate materials and processes. Primary areas of emphasis for the computational modeling work were coarse methodology, degradation of stack components, and electrochemical modeling: Coarse methodology • Improvements were made to both the SOFC-MP and SOFC ROM simulation tools. Degradation of stack components • Thermo-mechanical modeling and validation experiments were performed to understand/mitigate degradation of interconnects and seals during long-term stack operation. Electrochemical modeling 4 • Modeling tools were developed to improve understanding of electrochemical performance degradation of SOFCs related to changes in electrode microstructure and chemical interactions with contaminants. During FY13, PNNL continued to work with NETL to increase the extent of interaction between the SECA Core Technology Program and the SECA Industry Teams. In addition to using established mechanisms of communication, such as the annual SECA Workshop, representatives from PNNL and NETL participated in telecons and/or face-to-face meetings with all three industry teams during FY13. During these meetings, PNNL’s Core Technology Program work was presented in detail, after which feedback was solicited regarding current and future research topics. Results of PNNL’s SECA CTP work were also distributed via topical reports for the industry teams, DOE reports, technical society presentations, and papers in peer-reviewed technical journals. 5

  10. An In-Core Power Deposition and Fuel Thermal Environmental Monitor for Long-Lived Reactor Cores

    SciTech Connect (OSTI)

    Don W. Miller

    2004-09-28

    The primary objective of this program is to develop the Constant Temperature Power Sensor (CTPS) as in-core instrumentation that will provide a detailed map of local nuclear power deposition and coolant thermal-hydraulic conditions during the entire life of the core.

  11. Broad-band robustly single-mode hollow-core PCF by resonant filtering of higher order modes

    E-Print Network [OSTI]

    Günendi, Mehmet C; Frosz, Michael H; Russell, Philip St J

    2015-01-01

    We propose and theoretically analyse a novel hollow-core photonic crystal fibre (PCF) that is engineered so as to strongly suppress higher order modes, i.e., to provide robust LP$_{01}$ single-mode guidance in all the wavelength ranges where the fibre guides with low loss. Encircling the core is a single ring of non-touching glass elements whose modes are tailored to ensure resonant phase-matched coupling to higher-order core modes, causing them to leak at a very high rate into the supporting solid glass sheath. Using a model based on coupled capillary waveguides, as well as full vectorial finite element modelling, we show that this modal filtering effect depends on only one dimensionless geometrical parameter, akin to the well-known $d/{\\Lambda}$ parameter for endlessly single-mode solid-core PCF. The design is scalable up to large core sizes and is predicted to deliver LP$_{01}$ mode losses of some $10$s of dB/km in multiple transmission windows, the broadest of which spans more than an octave. At the same ...

  12. THE BLUE STRAGGLER STAR POPULATION IN NGC 1261: EVIDENCE FOR A POST-CORE-COLLAPSE BOUNCE STATE

    SciTech Connect (OSTI)

    Simunovic, Mirko; Puzia, Thomas H.; Sills, Alison E-mail: tpuzia@astro.puc.cl

    2014-11-01

    We present a multi-passband photometric study of the Blue Straggler Star (BSS) population in the Galactic globular cluster (GC) NGC 1261, using available space- and ground-based survey data. The inner BSS population is found to have two distinct sequences in the color-magnitude diagram (CMD), similar to double BSS sequences detected in other GCs. These well defined sequences are presumably linked to single short-lived events such as core collapse, which are expected to boost the formation of BSSs. In agreement with this, we find a BSS sequence in NGC 1261 which can be well reproduced individually by a theoretical model prediction of a 2 Gyr old population of stellar collision products, which are expected to form in the denser inner regions during short-lived core contraction phases. Additionally, we report the occurrence of a group of BSSs with unusually blue colors in the CMD, which are consistent with a corresponding model of a 200 Myr old population of stellar collision products. The properties of the NGC 1261 BSS populations, including their spatial distributions, suggest an advanced dynamical evolutionary state of the cluster, but the core of this GC does not show the classical signatures of core collapse. We argue that these apparent contradictions provide evidence for a post-core-collapse bounce state seen in dynamical simulations of old GCs.

  13. Improving the Models, SACOG Perspectives

    E-Print Network [OSTI]

    California at Davis, University of

    forecasting, Vehicle emissions, Health outcomes, RHNA allocations. #12;What is the state of the models? · Tour-based models implemented in larger MPOs are a significant improvement. · Trip-based models still used in other of models and data in the SCS process is not sufficient. · Transportation has early costs and later benefits

  14. Comparison of steam-generator liquid holdup and core uncovery in two facilities of differing scale

    SciTech Connect (OSTI)

    Motley, F.; Schultz, R.

    1987-01-01

    This paper reports on Run SB-CL-05, a test similar to Semiscale Run S-UT-8. The test results show that the core was uncovered briefly during the accident and that the rods overheated at certain core locations. Liquid holdup on the upflow side of the steam-generator tubes was observed. After the loop seal cleared, the core refilled and the rods cooled. These behaviors were similar to those observed in the Semiscale run. The Large-Scale Test Facility (LSTF) Run SB-CL-06 is a counterpart test to Semiscale Run S-LH-01. The comparison of the results of both tests shows similar phenomena. The similarity of phenomena in these two facilities build confidence that these results can be expected to occur in a PWR. Similar holdup has now been observed in the 6 tubes of Semiscale and in the 141 tubes of LSTF. It is now more believable that holdup may occur in a full-scale steam generator with 3000 or more tubes. These results confirm the scaling of these phenomena from Semiscale (1/1705) to LSTF (1/48). The TRAC results for SB-CL-05 are in reasonable agreement with the test data. TRAC predicted the core uncovery and resulting rod heatup. The liquid holdup on the upflow side of the steam-generator tubes was also correctly predicted. The clearing of the loop seal allowed core recovery and cooled the overheated rods just as it had in the data. The TRAC analysis results of Run SB-CL-05 are similar to those from Semiscale Run S-UT-8. The ability of the TRAC code to calculate the phenomena equally well in the two experiments of different scales confirms the scalability of the many models in the code that are important in calculating this small break.

  15. Burnup concept for a long-life fast reactor core using MCNPX.

    SciTech Connect (OSTI)

    Holschuh, Thomas Vernon,; Lewis, Tom Goslee,; Parma, Edward J.,

    2013-02-01

    This report describes a reactor design with a burnup concept for a long-life fast reactor core that was evaluated using Monte Carlo N-Particle eXtended (MCNPX). The current trend in advanced reactor design is the concept of a small modular reactor (SMR). However, very few of the SMR designs attempt to substantially increase the lifetime of a reactor core, especially without zone loading, fuel reshuffling, or other artificial mechanisms in the core that %E2%80%9Cflatten%E2%80%9D the power profile, including non-uniform cooling, non-uniform moderation, or strategic poison placement. Historically, the limitations of computing capabilities have prevented acceptable margins in the temporal component of the spatial excess reactivity in a reactor design, due primarily to the error in burnup calculations. This research was performed as an initial scoping analysis into the concept of a long-life fast reactor. It can be shown that a long-life fast reactor concept can be modeled using MCNPX to predict burnup and neutronics behavior. The inherent characteristic of this conceptual design is to minimize the change in reactivity over the lifetime of the reactor. This allows the reactor to operate substantially longer at full power than traditional Light Water Reactors (LWRs) or other SMR designs. For the purpose of this study, a single core design was investigated: a relatively small reactor core, yielding a medium amount of power (~200 to 400 MWth). The results of this scoping analysis were successful in providing a preliminary reactor design involving metal U-235/U-238 fuel with HT-9 fuel cladding and sodium coolant at a 20% volume fraction.

  16. GRAVITATIONAL WAVE SIGNATURES IN BLACK HOLE FORMING CORE COLLAPSE

    SciTech Connect (OSTI)

    Cerdá-Durán, Pablo; DeBrye, Nicolas; Aloy, Miguel A.; Font, José A.; Obergaulinger, Martin

    2013-12-20

    We present general relativistic numerical simulations of collapsing stellar cores. Our initial model consists of a low metallicity rapidly-rotating progenitor which is evolved in axisymmetry with the latest version of our general relativistic code CoCoNuT, which allows for black hole formation and includes the effects of a microphysical equation of state (LS220) and a neutrino leakage scheme to account for radiative losses. The motivation of our study is to analyze in detail the emission of gravitational waves in the collapsar scenario of long gamma-ray bursts. Our simulations show that the phase during which the proto-neutron star (PNS) survives before ultimately collapsing to a black hole is particularly optimal for gravitational wave emission. The high-amplitude waves last for several seconds and show a remarkable quasi-periodicity associated with the violent PNS dynamics, namely during the episodes of convection and the subsequent nonlinear development of the standing-accretion shock instability (SASI). By analyzing the spectrogram of our simulations we are able to identify the frequencies associated with the presence of g-modes and with the SASI motions at the PNS surface. We note that the gravitational waves emitted reach large enough amplitudes to be detected with third-generation detectors such as the Einstein Telescope within a Virgo Cluster volume at rates ? 0.1 yr{sup –1}.

  17. Irradiation-Accelerated Corrosion of Reactor Core Materials. Final Report

    SciTech Connect (OSTI)

    Jiao, Zhujie; Was, Gary; Bartels, David

    2015-04-02

    This project aims to understand how radiation accelerates corrosion of reactor core materials. The combination of high temperature, chemically aggressive coolants, a high radiation flux and mechanical stress poses a major challenge for the life extension of current light water reactors, as well as the success of most all GenIV concepts. Of these four drivers, the combination of radiation and corrosion places the most severe demands on materials, for which an understanding of the fundamental science is simply absent. Only a few experiments have been conducted to understand how corrosion occurs under irradiation, yet the limited data indicates that the effect is large; irradiation causes order of magnitude increases in corrosion rates. Without a firm understanding of the mechanisms by which radiation and corrosion interact in film formation, growth, breakdown and repair, the extension of the current LWR fleet beyond 60 years and the success of advanced nuclear energy systems are questionable. The proposed work will address the process of irradiation-accelerated corrosion that is important to all current and advanced reactor designs, but remains very poorly understood. An improved understanding of the role of irradiation in the corrosion process will provide the community with the tools to develop predictive models for in-reactor corrosion, and to address specific, important forms of corrosion such as irradiation assisted stress corrosion cracking.

  18. Cutting-edge issues of core-collapse supernova theory

    SciTech Connect (OSTI)

    Kotake, Kei [Department of Applied Physics, Faculty of Science, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka, 814-0180 (Japan); Nakamura, Ko [Faculty of Science and Engineering, Waseda University, Ohkubo 3-4-1, Shinjuku, Tokyo, 169-8555 (Japan); Kuroda, Takami [Department Physik, Universität Basel, Klingelbergstrasse 82, 4056 Basel (Switzerland); Takiwaki, Tomoya [Division of Theoretical Astronomy, National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo, 181-8588 (Japan)

    2014-05-02

    Based on multi-dimensional neutrino-radiation hydrodynamic simulations, we report several cutting-edge issues about the long-veiled explosion mechanism of core-collapse supernovae (CCSNe). In this contribution, we pay particular attention to whether three-dimensional (3D) hydrodynamics and/or general relativity (GR) would or would not help the onset of explosions. By performing 3D simulations with spectral neutrino transport, we show that it is more difficult to obtain an explosion in 3D than in 2D. In addition, our results from the first generation of full general relativistic 3D simulations including approximate neutrino transport indicate that GR can foster the onset of neutrino-driven explosions. Based on our recent parametric studies using a light-bulb scheme, we discuss impacts of nuclear energy deposition behind the supernova shock and stellar rotation on the neutrino-driven mechanism, both of which have yet to be included in the self-consistent 3D supernova models. Finally we give an outlook with a summary of the most urgent tasks to extract the information about the explosion mechanisms from multi-messenger CCSN observables.

  19. Thermal Conductivity from Core and Well log Data

    E-Print Network [OSTI]

    Hartmann, Andreas; Clauser, Christoph

    2008-01-01

    The relationships between thermal conductivity and other petrophysical properties have been analysed for a borehole drilled in a Tertiary Flysch sequence. We establish equations that permit us to predict rock thermal conductivity from logging data. A regression analysis of thermal conductivity, bulk density, and sonic velocity yields thermal conductivity with an average accuracy of better than 0.2 W/(m K). As a second step, logging data is used to compute a lithological depth profile, which in turn is used to calculate a thermal conductivity profile. From a comparison of the conductivity-depth profile and the laboratory data it can be concluded that thermal conductivity can be computed with an accuracy of less than 0.3 W/(m K)from conventional wireline data. The comparison of two different models shows that this approach can be practical even if old and incomplete logging data is used. The results can be used to infer thermal conductivity for boreholes without appropriate core data that are drilled in a simil...

  20. The Ecological Society of America wwwwww..ffrroonnttiieerrssiinneeccoollooggyy..oorrgg At its core, scientific knowledge is a collection of con-

    E-Print Network [OSTI]

    Mladenoff, David

    core, scientific knowledge is a collection of con- ceptual models that attempt to describe how the nat- ural world works and that have resisted repeated attempts to find empirical data to contradict them- tially increase scientific rigor and confidence in the results. The scientific precision expected

  1. THREE-DIMENSIONAL HYDRODYNAMIC CORE-COLLAPSE SUPERNOVA SIMULATIONS FOR AN 11.2 M{sub Sun} STAR WITH SPECTRAL NEUTRINO TRANSPORT

    SciTech Connect (OSTI)

    Takiwaki, Tomoya; Kotake, Kei; Suwa, Yudai

    2012-04-20

    We present numerical results on three-dimensional (3D) hydrodynamic core-collapse simulations of an 11.2 M{sub Sun} star. By comparing one-dimensional (1D) and two-dimensional (2D) results with those of 3D, we study how the increasing spacial multi-dimensionality affects the postbounce supernova dynamics. The calculations were performed with an energy-dependent treatment of the neutrino transport that is solved by the isotropic diffusion source approximation scheme. In agreement with previous study, our 1D model does not produce explosions for the 11.2 M{sub Sun} star, while the neutrino-driven revival of the stalled bounce shock is obtained in both the 2D and 3D models. The standing accretion-shock instability (SASI) is observed in the 3D models, in which the dominant mode of the SASI is bipolar (l = 2) with its saturation amplitudes being slightly smaller than 2D. By performing a tracer-particle analysis, we show that the maximum residency time of material in the gain region becomes longer in 3D than in 2D due to non-axisymmetric flow motions, which is one of advantageous aspects of 3D models to obtain neutrino-driven explosions. Our results show that convective matter motions below the gain radius become much more violent in 3D than in 2D, making the neutrino luminosity larger for 3D. Nevertheless, the emitted neutrino energies are made smaller due to the enhanced cooling. Our results indicate whether these advantages for driving 3D explosions could or could not overwhelm the disadvantages is sensitive to the employed numerical resolutions. An encouraging finding is that the shock expansion tends to become more energetic for models with finer resolutions. To draw a robust conclusion, 3D simulations with much higher numerical resolutions and with more advanced treatment of neutrino transport and of gravity are needed, which could be practicable by utilizing forthcoming Petaflops-class supercomputers.

  2. How much potassium is in the Earth's core? New insights from partitioning experiments

    E-Print Network [OSTI]

    Mcdonough, William F.

    of the magnetic field and convection in the outer core and mantle are intimately linked to the amount of heat) that are potentially present in the core. In the absence of radioactive heating, predicted high rates of core present in the core. In addition to primordial heat, the latent heat of crystallization of the inner core

  3. Apparatus and method for controlling the temperature of the core of a super-conducting transformer

    SciTech Connect (OSTI)

    Golner, Thomas; Pleva, Edward; Mehta, Shirish

    2006-10-10

    An apparatus for controlling the temperature of a core of a transformer is provided that includes a core, a shield surrounding the core, a cast formed between the core and the shield, and tubing positioned on the shield. The cast directs heat from the core to the shield and cooling fluid is directed through the tubing to cool the shield.

  4. Concentric core optical fiber with multiple-mode signal transmission

    DOE Patents [OSTI]

    Muhs, J.D.

    1997-05-06

    A concentric core optical fiber provides for the simultaneous but independent transmission of signals over a single optical fiber. The concentric optical fiber is constructed of a single-mode or multimode inner optical fiber defined by a core and a cladding of a lower index of refraction than the core and an outer optical fiber defined by additional cladding concentrically disposed around the cladding and of an index of refraction lower than the first mentioned cladding whereby the latter functions as the core of the outer optical fiber. By employing such an optical fiber construction with a single-mode inner core or optical fiber, highly sensitive interferometric and stable less sensitive amplitude based sensors can be placed along the same length of a concentric core optical fiber. Also, by employing the concentric core optical fiber secure telecommunications can be achieved via the inner optical fiber since an intrusion of the concentric optical fiber will first cause a variation in the light being transmitted through the outer optical fiber and this variation of light being used to trigger a suitable alarm indicative of the intrusion. 3 figs.

  5. One pass core design of a super fast reactor

    SciTech Connect (OSTI)

    Liu, Qingjie; Oka, Yoshiaki

    2013-07-01

    One pass core design for Supercritical-pressure light water-cooled fast reactor (Super FR) is proposed. The whole core is cooled with upward flow in one through flow pattern like PWR. Compared with the previous two pass core design; this new flow pattern can significantly simplify the core concept. Upper core structure, coolant flow scheme as well as refueling procedure are as simple as in PWR. In one pass core design, supercritical-pressure water is at approximately 25.0 MPa and enters the core at 280 C. degrees and is heated up in one through flow pattern upwardly to the average outlet temperature of 500 C. degrees. Great density change in vertical direction can cause significant axial power offset during the cycle. Meanwhile, Pu accumulated in the UO{sub 2} fuel blanket assemblies also introduces great power increase during cycle, which requires large amount of flow for heat removal and makes the outlet temperature of blanket low at the beginning of equilibrium cycle (BOEC). To deal with these issues, some MOX fuel is applied in the bottom region of the blanket assembly. This can help to mitigate the power change in blanket due to Pu accumulation and to increase the outlet temperature of the blanket during cycle. Neutron transport and thermohydraulics coupled calculation shows that this design can satisfy the requirement in the Super FR principle for both 500 C. degrees outlet temperature and negative coolant void reactivity. (authors)

  6. Modeling of transformers using circuit simulators

    SciTech Connect (OSTI)

    Archer, W.E.; Deveney, M.F.; Nagel, R.L.

    1994-07-01

    Transformers of two different designs; and unencapsulated pot core and an encapsulated toroidal core have been modeled for circuit analysis with circuit simulation tools. We selected MicroSim`s PSPICE and Anology`s SABER as the simulation tools and used experimental BH Loop and network analyzer measurements to generate the needed input data. The models are compared for accuracy and convergence using the circuit simulators. Results are presented which demonstrate the effects on circuit performance from magnetic core losses, eddy currents, and mechanical stress on the magnetic cores.

  7. Weak decay processes in pre-supernova core evolution within the gross theory

    SciTech Connect (OSTI)

    Ferreira, R. C.; Dimarco, A. J.; Samana, A. R.; Barbero, C. A.

    2014-03-20

    The beta decay and electron capture rates are of fundamental importance in the evolution of massive stars in a pre-supernova core. The beta decay process gives its contribution by emitting electrons in the plasma of the stellar core, thereby increasing pressure, which in turn increases the temperature. From the other side, the electron capture removes free electrons from the plasma of the star core contributing to the reduction of pressure and temperature. In this work we calculate the beta decay and electron capture rates in stellar conditions for 63 nuclei of relevance in the pre-supernova stage, employing Gross Theory as the nuclear model. We use the abundances calculated with the Saha equations in the hypothesis of nuclear statistical equilibrium to evaluate the time derivative of the fraction of electrons. Our results are compared with other evaluations available in the literature. They have shown to be one order less or equal than the calculated within other models. Our results indicate that these differences may influence the evolution of the star in the later stages of pre-supernova.

  8. Assessment of core damage frequency owing to possible fires at NPP with RBMK type reactors

    SciTech Connect (OSTI)

    Vinnikov, B. [National Research Centre Kurchatov Inst., 1, Kurchatov Square, Moscow, 123 182 (Russian Federation); NRC Kurchatov Inst. (Russian Federation)

    2012-07-01

    According to Scientific and Technical Cooperation between the USA and Russia in the field of nuclear engineering the Idaho National Laboratory has transferred to the possession of the National Research Center ' Kurchatov Inst. ' the SAPHIRE software without any fee. With the help of the software Kurchatov Inst. developed a Pilot Living PSA- Model of Leningrad NPP Unit 1. Computations of core damage frequencies were carried out for additional Initiating Events. In the submitted paper such additional Initiating Events are fires in various compartments of the NPP. During the computations of each fire, structure of the PSA - Model was not changed, but Fault Trees for the appropriate systems, which are removed from service during the fire, were changed. It follows from the computations, that for ten fires Core Damaged Frequencies (CDF) are not changed. Other six fires will cause additional core damage. On the basis of the calculated results it is possible to determine a degree of importance of these fires and to establish sequence of performance of fire-prevention measures in various places of the NPP. (authors)

  9. Thermal hydraulic method for whole core design analysis of an HTGR

    SciTech Connect (OSTI)

    Huning, A. J.; Garimella, S. [George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA (United States)

    2013-07-01

    A new thermal hydraulic method and initial results are presented for core-wide steady state analysis of prismatic High Temperature Gas-Cooled Reactors (HTGR). The method allows for the complete solution of temperature and coolant mass flow distribution by solving quasi-steady energy balances for the discretized core. Assembly blocks are discretized into unit cells for which the average temperature of each unit cell is determined. Convective heat removal is coupled to the unit cell energy balances by a 1-D axial flow model. The flow model uses established correlations for friction factor and Nusselt number. Bypass flow is explicitly calculated by using an initial guess for mass flow distribution and determining the exit pressure of each flow channel. The mass flow distribution is updated until a uniform core exit pressure condition is reached. Results are obtained for the MHTGR-350 with emphasis on the change in thermal hydraulic parameters due to various steady state power profiles and bypass gap widths. Steady state temperature distribution and its variations are discussed. (authors)

  10. Evaluation of Neutron Radiography Reactor LEU-Core Start-Up Measurements

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

    Bess, John D.; Maddock, Thomas L.; Smolinski, Andrew T.; Marshall, Margaret A.

    2014-11-04

    Benchmark models were developed to evaluate the cold-critical start-up measurements performed during the fresh core reload of the Neutron Radiography (NRAD) reactor with Low Enriched Uranium (LEU) fuel. Experiments include criticality, control-rod worth measurements, shutdown margin, and excess reactivity for four core loadings with 56, 60, 62, and 64 fuel elements. The worth of four graphite reflector block assemblies and an empty dry tube used for experiment irradiations were also measured and evaluated for the 60-fuel-element core configuration. Dominant uncertainties in the experimental keff come from uncertainties in the manganese content and impurities in the stainless steel fuel cladding asmore »well as the 236U and erbium poison content in the fuel matrix. Calculations with MCNP5 and ENDF/B-VII.0 neutron nuclear data are approximately 1.4% (9?) greater than the benchmark model eigenvalues, which is commonly seen in Monte Carlo simulations of other TRIGA reactors. Simulations of the worth measurements are within the 2? uncertainty for most of the benchmark experiment worth values. The complete benchmark evaluation details are available in the 2014 edition of the International Handbook of Evaluated Reactor Physics Benchmark Experiments.« less

  11. THR-TH: a high-temperature gas-cooled nuclear reactor core thermal hydraulics code

    SciTech Connect (OSTI)

    Vondy, D.R.

    1984-07-01

    The ORNL version of PEBBLE, the (RZ) pebble bed thermal hydraulics code, has been extended for application to a prismatic gas cooled reactor core. The supplemental treatment is of one-dimensional coolant flow in up to a three-dimensional core description. Power density data from a neutronics and exposure calculation are used as the basic information for the thermal hydraulics calculation of heat removal. Two-dimensional neutronics results may be expanded for a three-dimensional hydraulics calculation. The geometric description for the hydraulics problem is the same as used by the neutronics code. A two-dimensional thermal cell model is used to predict temperatures in the fuel channel. The capability is available in the local BOLD VENTURE computation system for reactor core analysis with capability to account for the effect of temperature feedback by nuclear cross section correlation. Some enhancements have also been added to the original code to add pebble bed modeling flexibility and to generate useful auxiliary results. For example, an estimate is made of the distribution of fuel temperatures based on average and extreme conditions regularly calculated at a number of locations.

  12. Performance analysis of distributed symmetric sparse matrix vector multiplication algorithm for multi-core architectures

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

    Oryspayev, Dossay; Aktulga, Hasan Metin; Sosonkina, Masha; Maris, Pieter; Vary, James P.

    2015-07-14

    In this article, sparse matrix vector multiply (SpMVM) is an important kernel that frequently arises in high performance computing applications. Due to its low arithmetic intensity, several approaches have been proposed in literature to improve its scalability and efficiency in large scale computations. In this paper, our target systems are high end multi-core architectures and we use messaging passing interface + open multiprocessing hybrid programming model for parallelism. We analyze the performance of recently proposed implementation of the distributed symmetric SpMVM, originally developed for large sparse symmetric matrices arising in ab initio nuclear structure calculations. We also study important featuresmore »of this implementation and compare with previously reported implementations that do not exploit underlying symmetry. Our SpMVM implementations leverage the hybrid paradigm to efficiently overlap expensive communications with computations. Our main comparison criterion is the "CPU core hours" metric, which is the main measure of resource usage on supercomputers. We analyze the effects of topology-aware mapping heuristic using simplified network load model. Furthermore, we have tested the different SpMVM implementations on two large clusters with 3D Torus and Dragonfly topology. Our results show that the distributed SpMVM implementation that exploits matrix symmetry and hides communication yields the best value for the "CPU core hours" metric and significantly reduces data movement overheads.« less

  13. Evaluation of Neutron Radiography Reactor LEU-Core Start-Up Measurements

    SciTech Connect (OSTI)

    Bess, John D.; Maddock, Thomas L.; Smolinski, Andrew T.; Marshall, Margaret A.

    2014-11-04

    Benchmark models were developed to evaluate the cold-critical start-up measurements performed during the fresh core reload of the Neutron Radiography (NRAD) reactor with Low Enriched Uranium (LEU) fuel. Experiments include criticality, control-rod worth measurements, shutdown margin, and excess reactivity for four core loadings with 56, 60, 62, and 64 fuel elements. The worth of four graphite reflector block assemblies and an empty dry tube used for experiment irradiations were also measured and evaluated for the 60-fuel-element core configuration. Dominant uncertainties in the experimental keff come from uncertainties in the manganese content and impurities in the stainless steel fuel cladding as well as the 236U and erbium poison content in the fuel matrix. Calculations with MCNP5 and ENDF/B-VII.0 neutron nuclear data are approximately 1.4% (9?) greater than the benchmark model eigenvalues, which is commonly seen in Monte Carlo simulations of other TRIGA reactors. Simulations of the worth measurements are within the 2? uncertainty for most of the benchmark experiment worth values. The complete benchmark evaluation details are available in the 2014 edition of the International Handbook of Evaluated Reactor Physics Benchmark Experiments.

  14. Evaluation of Neutron Radiography Reactor LEU-Core Start-Up Measurements

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

    None

    2014-11-04

    Benchmark models were developed to evaluate the cold-critical start-up measurements performed during the fresh core reload of the Neutron Radiography (NRAD) reactor with Low Enriched Uranium (LEU) fuel. Experiments include criticality, control-rod worth measurements, shutdown margin, and excess reactivity for four core loadings with 56, 60, 62, and 64 fuel elements. The worth of four graphite reflector block assemblies and an empty dry tube used for experiment irradiations were also measured and evaluated for the 60-fuel-element core configuration. Dominant uncertainties in the experimental keff come from uncertainties in the manganese content and impurities in the stainless steel fuel cladding as well as the 236U and erbium poison content in the fuel matrix. Calculations with MCNP5 and ENDF/B-VII.0 neutron nuclear data are approximately 1.4% (9?) greater than the benchmark model eigenvalues, which is commonly seen in Monte Carlo simulations of other TRIGA reactors. Simulations of the worth measurements are within the 2? uncertainty for most of the benchmark experiment worth values. The complete benchmark evaluation details are available in the 2014 edition of the International Handbook of Evaluated Reactor Physics Benchmark Experiments.

  15. CARBON ISOTOPE AND ISOTOPOMER FRACTIONATION IN COLD DENSE CLOUD CORES

    SciTech Connect (OSTI)

    Furuya, Kenji; Aikawa, Yuri [Department of Earth and Planetary Sciences, Kobe University, Kobe 657-8501 (Japan); Sakai, Nami; Yamamoto, Satoshi, E-mail: furuya@stu.kobe-u.ac.jp [Department of Physics and Research Center for the Early Universe, University of Tokyo, Bunkyo-ku, Tokyo 113-003 (Japan)

    2011-04-10

    We construct a gas-grain chemical network model which includes carbon isotopes ({sup 12}C and {sup 13}C) with an emphasis on isotopomer-exchange reactions. Temporal variations of molecular abundances, the carbon isotope ratios ({sup 12}CX/{sup 13}CX), and the isotopomer ratios ({sup 12}C{sup 13}CX/{sup 13}C{sup 12}CX) of CCH and CCS in cold dense cloud cores are investigated by numerical calculations. We confirm that the isotope ratios of molecules, both in the gas phase and grain surfaces, are significantly different depending on whether the molecule is formed from the carbon atom (ion) or the CO molecule. Molecules formed from carbon atoms have CX/{sup 13}CX ratios greater than the elemental abundance ratio of [{sup 12}C/{sup 13}C]. On the other hand, molecules formed from CO molecules have CX/{sup 13}CX ratios smaller than the [{sup 12}C/{sup 13}C] ratio. We reproduce the observed C{sup 13}CH/{sup 13}CCH ratio in TMC-1, if the isotopomer-exchange reaction, {sup 13}CCH + H {r_reversible} C{sup 13}CH + H + 8.1 K, proceeds with the forward rate coefficient k{sub f} > 10{sup -11} cm{sup 3} s{sup -1}. However, the C{sup 13}CS/{sup 13}CCS ratio is lower than that observed in TMC-1. We then assume the isotopomer-exchange reaction catalyzed by the H atom, {sup 13}CCS + H {r_reversible} C{sup 13}CS + H + 17.4 K. In the model with this reaction, we reproduce the observed C{sup 13}CS/{sup 13}CCS, CCS/C{sup 13}CS, and CCS/{sup 13}CCS ratios simultaneously.

  16. Critical surface for explosions of rotational core-collapse supernovae

    SciTech Connect (OSTI)

    Iwakami, Wakana; Nagakura, Hiroki [Yukawa Institute for Theoretical Physics, Kyoto University, Oiwake-cho, Kitashirakawa, Sakyo-ku, Kyoto, 606-8502 (Japan); Yamada, Shoichi, E-mail: wakana@heap.phys.waseda.ac.jp [Advanced Research Institute for Science and Engineering, Waseda University, 3-4-1, Okubo, Shinjuku, Tokyo, 169-8555 (Japan)

    2014-09-20

    The effect of rotation on the explosion of core-collapse supernovae is investigated systematically in three-dimensional simulations. In order to obtain the critical conditions for explosion as a function of mass accretion rate, neutrino luminosity, and specific angular momentum, rigidly rotating matter was injected from the outer boundary with an angular momentum, which is increased every 500 ms. It is found that there is a critical value of the specific angular momentum, above which the standing shock wave revives, for a given combination of mass accretion rate and neutrino luminosity, i.e., an explosion can occur by rotation even if the neutrino luminosity is lower than the critical value for a given mass accretion rate in non-rotational models. The coupling of rotation and hydrodynamical instabilities plays an important role in characterizing the dynamics of shock revival for the range of specific angular momentum that are supposed to be realistic. Contrary to expectations from past studies, the most rapidly expanding direction of the shock wave is not aligned with the rotation axis. Being perpendicular to the rotation axis on average, it can be oriented in various directions. Its dispersion is small when the spiral mode of the standing accretion shock instability (SASI) governs the dynamics, while it is large when neutrino-driven convection is dominant. As a result of the comparison between two-dimensional and three-dimensional rotational models, it is found that m ? 0 modes of neutrino-driven convection or SASI are important for shock revival around the critical surface.

  17. CORE ELECTRON HEATING IN SOLAR WIND RECONNECTION EXHAUSTS

    SciTech Connect (OSTI)

    Pulupa, M. P.; Salem, C.; Phan, T. D.; Bale, S. D.; Gosling, J. T.

    2014-08-10

    We present observational evidence of core electron heating in solar wind reconnection exhausts. We show two example events, one which shows clear heating of the core electrons within the exhaust, and one which demonstrates no heating. The event with heating occurred during a period of high inflow Alfvén speed (V {sub AL}), while the event with no heating had a low V {sub AL}. This agrees with the results of a recent study of magnetopause exhausts, and suggests that similar core electron heating can occur in both symmetric (solar wind) and asymmetric (magnetopause) exhausts.

  18. propagate away from the wells and disturbs a larger and larger volume, the probability increases

    E-Print Network [OSTI]

    Benton, Michael

    be linked to disposal of fluids gen- erated during Oklahoma dewatering and after hydraulic fracturing seismic hazard. Regular measurements of reservoir pressure at a range of distances and azimuths from high. A. McGarr, J. Geophys. Res. 119, 1008­1019 (2014). 9. The Central and Eastern United States

  19. Surface-Defects and Core Excitons at the (2x1) Asymmetric-Dimer (100) Surface of Si 

    E-Print Network [OSTI]

    BOWEN, MA; Allen, Roland E.; DOW, JD.

    1984-01-01

    VOLUME 30, NUMBER 8 15 OCTOBER 1984 Surface defects and core excitons at the (2X 1) asymmetric-dimer (100) surface of Si Marshall A. Bowen Department ofPhysics, Western Illinois University, Macomb, Illinois 61455 Roland E. Allen Department of... with 28 sp3- bonded substitutional defects, and (ii) energies of Hjalmarson-Frenkel core excitons 'at the (100) sur- face of Si, reconstructed according to Chadi s (2& 1) asymmetric-dimer model. The predictions sug- gest that P at. this surface should...

  20. Core and wing densities of asymmetric coronal spectral profiles: Implications for the mass supply of the solar corona

    SciTech Connect (OSTI)

    Patsourakos, S.; Klimchuk, J. A.; Young, P. R. E-mail: james.a.klimchuk@nasa.gov

    2014-02-01

    Recent solar spectroscopic observations have shown that coronal spectral lines can exhibit asymmetric profiles, with enhanced emissions at their blue wings. These asymmetries correspond to rapidly upflowing plasmas at speeds exceeding ?50 km s{sup –1}. Here, we perform a study of the density of the rapidly upflowing material and compare it with that of the line core that corresponds to the bulk of the plasma. For this task, we use spectroscopic observations of several active regions taken by the Extreme Ultraviolet Imaging Spectrometer of the Hinode mission. The density sensitive ratio of the Fe XIV lines at 264.78 and 274.20 Å is used to determine wing and core densities. We compute the ratio of the blue wing density to the core density and find that most values are of order unity. This is consistent with the predictions for coronal nanoflares if most of the observed coronal mass is supplied by chromospheric evaporation driven by the nanoflares. However, much larger blue wing-to-core density ratios are predicted if most of the coronal mass is supplied by heated material ejected with type II spicules. Our measurements do not rule out a spicule origin for the blue wing emission, but they argue against spicules being a primary source of the hot plasma in the corona. We note that only about 40% of the pixels where line blends could be safely ignored have blue wing asymmetries in both Fe XIV lines. Anticipated sub-arcsecond spatial resolution spectroscopic observations in future missions could shed more light on the origin of blue, red, and mixed asymmetries.

  1. Dipolar interactions, molecular flexibility, and flexoelectricity in bent-core liquid crystals

    E-Print Network [OSTI]

    Alastair Dewar; Philip J. Camp

    2005-05-06

    The effects of dipolar interactions and molecular flexibility on the structure and phase behavior of bent-core molecular fluids are studied using Monte Carlo computer simulations. Some calculations of flexoelectric coefficients are also reported. The rigid cores of the model molecules consist of either five or seven soft spheres arranged in a `V' shape with external bend angle $\\gamma$. With purely repulsive sphere-sphere interactions and $\\gamma=0^\\circ$ (linear molecules) the seven-sphere model exhibits isotropic, uniaxial nematic, smectic-A, and tilted phases. With $\\gamma \\geq 20^\\circ$ the smectic-A phase disappears, while the system with $\\gamma \\geq 40^\\circ$ shows a direct tilted smectic--isotropic fluid transition. The addition of electrostatic interactions between transverse dipole moments on the apical spheres is generally seen to reduce the degree of tilt in the smectic and solid phases, destabilize the nematic and smectic-A phases of linear molecules, and destabilize the tilted smectic-B phase of bent-core molecules. The effects of adding three-segment flexible tails to the ends of five-sphere bent-core molecules are examined using configurational-bias Monte Carlo simulations. Only isotropic and smectic phases are observed. On the one hand, molecular flexibility gives rise to pronounced fluctuations in the smectic-layer structure, bringing the simulated system in better correspondence with real materials; on the other hand, the smectic phase shows almost no tilt. Lastly, the flexoelectric coefficients of various nematic phases -- with and without attractive sphere-sphere interactions -- are presented. The results are encouraging, but the computational effort required is a drawback associated with the use of fluctuation relations.

  2. UPDATED Year One Self-Evaluation Report Standard One: Mission, Core Themes, and Expectations

    E-Print Network [OSTI]

    Maxwell, Bruce D.

    UPDATED Year One Self-Evaluation Report Standard One: Mission, Core Themes, and Expectations.................................................................................6 Chapter One ­ Standard One: Mission, Core Themes, and Expectations...........................................................................................................................10 Section 1B. Core Themes

  3. Year One Self-Evaluation Report Standard One: Mission, Core Themes, and Expectations

    E-Print Network [OSTI]

    Maxwell, Bruce D.

    Year One Self-Evaluation Report Standard One: Mission, Core Themes, and Expectations Submitted ...........................................................................12 Chapter One ­ Standard One: Mission, Core Themes, and Expectations..........................................................................................................................20 Section 1B. Core Themes

  4. Scattering of infrared light by dielectric core-shell particles

    E-Print Network [OSTI]

    Thiessen, E; Heinisch, R L; Fehske, H

    2015-01-01

    We study the scattering of infrared light by small dielectric core-shell particles taking a sapphire sphere with a CaO core as an example. The extinction efficiency of such a particle shows two intense series of resonances attached, respectively, to in-phase and out-of-phase multipolar polarization-induced surface charges build-up, respectively, at the core-shell and the shell-vacuum interface. Both series, the character of the former may be labelled bonding and the character of the latter antibonding, give rise to anomalous scattering. For a given particle radius and filling factor the Poynting vector field shows therefore around two wave numbers the complex topology of this type of light scattering. Inside the particle the topology depends on the character of the resonance. The dissipation of energy inside the particle also reflects the core-shell structure. It depends on the resonance and shows strong spatial variations.

  5. Solid0Core Heat-Pipe Nuclear Batterly Type Reactor

    SciTech Connect (OSTI)

    Ehud Greenspan

    2008-09-30

    This project was devoted to a preliminary assessment of the feasibility of designing an Encapsulated Nuclear Heat Source (ENHS) reactor to have a solid core from which heat is removed by liquid-metal heat pipes (HP).

  6. A Critique of Core--Collapse Supernova Theory Circa 1997

    E-Print Network [OSTI]

    Adam Burrows

    1997-03-02

    There has been a new infusion of ideas in the study of the mechanism and early character of core--collapse supernovae. However, despite recent conceptual and computational progress, fundamental questions remain. Some are summarize herein.

  7. Evidence for a Weak Iron Core at Earth's Center

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

    iron grains in the Earth's inner core comes from x-ray spectroscopy and diffraction measurements performed at high pressure and utilizing, in part, ALS Beamline 12.2.2. When...

  8. Ultrafast Core-Hole Induced Dynamics in Water

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

    the fluorescence from an electron reoccupying the oxygen 1s core level is measured. For hydrogen-bonded systems such as liquid water, ultrafast dynamics that occur during the...

  9. THERMAL PROPERTIES OF GABLE MOUNTAIN BASALT CORES HANFORD NUCLEAR RESERVATION

    E-Print Network [OSTI]

    Martinez-Baez, L.F.

    2011-01-01

    70 THERMAL PROPERTIES OF GABLE MOUNTAIN BASALT CORES HANFORDft); we used the data giyen for Gable Mountain K1005 for oursamples of Gable Mountain DB-5 (521 ft and 524 ft); and we

  10. A many-core software framework for embedded space computing

    E-Print Network [OSTI]

    Sun, Eugene Yu-Ting

    2013-01-01

    Space computing has long called for powerful yet power-efficient hardware for on-board computation. The emergence of many-core CPUs on a single die provides one potential solution. The development of processors like Maestro ...

  11. Microthermometry of Fluid Inclusions from the VC-1 Core Hole...

    Open Energy Info (EERE)

    Caldera, New Mexico Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: Microthermometry of Fluid Inclusions from the VC-1 Core Hole in Valles...

  12. Loading rubidium atoms into a hollow core fiber

    E-Print Network [OSTI]

    Chu, Yiwen

    2007-01-01

    We demonstrate a procedure for cooling, trapping, and transferring rubidium atoms into a hollow core photonic band gap fiber. The atoms are first collected in a magneto-optical trap (MOT) and then cooled using polarization ...

  13. Technical note CoreFlow: A computational platform for integration,

    E-Print Network [OSTI]

    . CoreFlow is being released to the scientific community as an open-sourced software package complete with proteomics-specific examples, which include corrections for incomplete isotopic labeling of peptides (SILAC

  14. Superconducting shielded core reactor with reduced AC losses

    DOE Patents [OSTI]

    Cha, Yung S.; Hull, John R.

    2006-04-04

    A superconducting shielded core reactor (SSCR) operates as a passive device for limiting excessive AC current in a circuit operating at a high power level under a fault condition such as shorting. The SSCR includes a ferromagnetic core which may be either closed or open (with an air gap) and extends into and through a superconducting tube or superconducting rings arranged in a stacked array. First and second series connected copper coils each disposed about a portion of the iron core are connected to the circuit to be protected and are respectively wound inside and outside of the superconducting tube or rings. A large impedance is inserted into the circuit by the core when the shielding capability of the superconducting arrangement is exceeded by the applied magnetic field generated by the two coils under a fault condition to limit the AC current in the circuit. The proposed SSCR also affords reduced AC loss compared to conventional SSCRs under continuous normal operation.

  15. Hanging core support system for a nuclear reactor. [LMFBR

    DOE Patents [OSTI]

    Burelbach, J.P.; Kann, W.J.; Pan, Y.C.; Saiveau, J.G.; Seidensticker, R.W.

    1984-04-26

    For holding the reactor core in the confining reactor vessel, a support is disclosed that is structurally independent of the vessel, that is dimensionally accurate and stable, and that comprises tandem tension linkages that act redundantly of one another to maintain stabilized core support even in the unlikely event of the complete failure of one of the linkages. The core support has a mounting platform for the reactor core, and unitary structure including a flange overlying the top edge of the reactor vessels, and a skirt and box beams between the flange and platform for establishing one of the linkages. A plurality of tension rods connect between the deck closing the reactor vessel and the platform for establishing the redundant linkage. Loaded Belleville springs flexibly hold the tension rods at the deck and separable bayonet-type connections hold the tension rods at the platform.

  16. Mineral Deformation at Earth's Core-Mantle Boundary

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

    Mineral Deformation at Earth's Core-Mantle Boundary Print Earth is a dynamic planet in which convection takes place on the scale of thousands of kilometers. Because Earth is mostly...

  17. Evidence for a Weak Iron Core at Earth's Center

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

    Iron Core at Earth's Center Print Seismic waves that pass through the center of the Earth travel faster going from pole to pole than along the equatorial plane-why? One theory...

  18. Thermal barrier and support for nuclear reactor fuel core

    DOE Patents [OSTI]

    Betts, Jr., William S. (Del Mar, CA); Pickering, J. Larry (Del Mar, CA); Black, William E. (San Diego, CA)

    1987-01-01

    A thermal barrier/core support for the fuel core of a nuclear reactor having a metallic cylinder secured to the reactor vessel liner and surrounded by fibrous insulation material. A top cap is secured to the upper end of the metallic cylinder that locates and orients a cover block and post seat. Under normal operating conditions, the metallic cylinder supports the entire load exerted by its associated fuel core post. Disposed within the metallic cylinder is a column of ceramic material, the height of which is less than that of the metallic cylinder, and thus is not normally load bearing. In the event of a temperature excursion beyond the design limits of the metallic cylinder and resulting in deformation of the cylinder, the ceramic column will abut the top cap to support the fuel core post.

  19. Determining SQL Server 2012 Core Licensing Requirements at SA Renewal

    E-Print Network [OSTI]

    Chaudhuri, Surajit

    Determining SQL Server 2012 Core Licensing Requirements at SA Renewal June 2012 #12;2 Table......................................................................................................................................................................................................4 How to Create a SQL Server 2012 Transition Report .............................................................................................11 Discover SQL Server installations

  20. A Plastic-Core Compact Heat Exchanger for Energy Conservation 

    E-Print Network [OSTI]

    Lazaridis, A.; Rafailidis, E.

    1995-01-01

    This paper describes a compact, single-pass, cross-flow type, gas-to-gas heat exchanger with a polyolefin (polyethylene or polypropylene) core whose seams are welded through a proprietary process. It is constructed of several extruded polyolefin...

  1. Ultrafast Core-Hole Induced Dynamics in Water

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

    The situation gets further complicated when you add ionizing x-ray radiation to the mix: the energy from the radiation is enough to eject an electron from the core of the...

  2. Core Holes At Valles Caldera - Sulphur Springs Geothermal Area...

    Open Energy Info (EERE)

    Dennis L. Nielson, Pisto Larry, C.W. Criswell, R. Gribble, K. Meeker, J.A. Musgrave, T. Smith, D. Wilson (1989) Scientific Core Hole Valles Caldera No. 2B (VC-2B), New Mexico:...

  3. Core of First Section of New Accelerator Rolled Out | Jefferson...

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

    and rolled out for further assembly. This "string" of components will become the heart of a cryomodule, which will be added to the lab's particle accelerator in 2012. Core...

  4. Doubling Estimates of Light Elements in the Earth's Core | Advanced...

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

    relation of both hcp-Fe and the iron-silicon alloy at 300 K. The inner core of the Earth is the remotest area on the globe, mostly impossible to study directly. It is an area...

  5. The Chemistry of Cold Interstellar Cloud Cores Eric Herbst

    E-Print Network [OSTI]

    Millar, Tom

    Chapter 1 The Chemistry of Cold Interstellar Cloud Cores Eric Herbst Department of Physics and Their Chemistry . . . . . . . . . . . . . 4 1.2 Gas-Phase Chemical Processes . . . . . . . . . . . . . . . . . . . . . . . . . . 13 1.2.4 Organic Chemistry . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 1.2.5 Negative

  6. Dose Rate Calculations for Rotary Mode Core Sampling Exhauster

    SciTech Connect (OSTI)

    FOUST, D.J.

    2000-10-26

    This document provides the calculated estimated dose rates for three external locations on the Rotary Mode Core Sampling (RMCS) exhauster HEPA filter housing, per the request of Characterization Field Engineering.

  7. High-voltage air-core pulse transformers

    SciTech Connect (OSTI)

    Rohwein, G. J.

    1981-01-01

    General types of air core pulse transformers designed for high voltage pulse generation and energy transfer applications are discussed with special emphasis on pulse charging systems which operate up to the multi-megavolt range. The design, operation, dielectric materials, and performance are described. It is concluded that high voltage air core pulse transformers are best suited to applications outside the normal ranges of conventional magnetic core transformers. In general these include charge transfer at high power levels and fast pulse generation with comparatively low energy. When properly designed and constructed, they are capable of delivering high energy transfer efficiency and have demonstrated superior high voltage endurance. The principal disadvantage of high voltage air core transformers is that they are not generally available from commercial sources. Consequently, the potential user must become thoroughly familiar with all aspects of design, fabrication and system application before he can produce a high performance transformer system. (LCL)

  8. Neutronic evaluation of GCFR core diluents and reflectors

    E-Print Network [OSTI]

    Yu, Kun, 1974-

    2003-01-01

    Materials are evaluated for use as in-core diluents and as peripheral reflectors for Gas-Cooled Fast Reactor (GFR) service, using coupled Monte Carlo (MCNP) and isotopics (ORIGEN) codes. The principal performance indices ...

  9. Evidence for a Weak Iron Core at Earth's Center

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

    Evidence for a Weak Iron Core at Earth's Center Print Seismic waves that pass through the center of the Earth travel faster going from pole to pole than along the equatorial...

  10. Evidence for a Weak Iron Core at Earth's Center

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

    Evidence for a Weak Iron Core at Earth's Center Print Wednesday, 30 April 2014 00:00 Seismic waves that pass through the center of the Earth travel faster going from pole to pole...

  11. Aerosol generation from sparging of molten pools of corium by gases released from core-concrete interactions. [PWR; BWR

    SciTech Connect (OSTI)

    Ginsberg, T.

    1983-02-01

    A model for calculation of the aerosol generation rate resulting from surface bubble rupture during molten core-concrete interactions is discussed. One aspect of the model, based upon previous work in the literature, considers that film rupture occurs due to growth of film oscillation disturbances in the surface liquid film. Calculations are presented for molten pools with liquid properties in the range of prototypic interest.

  12. Uranium - thorium series study on Yucatan slope cores 

    E-Print Network [OSTI]

    Exner, Mary Elizabeth

    1972-01-01

    URANIUM ? THORIUM SERIES STUDY ON YUCATAN SLOPE CORES A Thesis by Mary Elizabeth Exner Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE August, 1972... Major Subject: Oceanography URANIUM ? THORIUM SERIES STUDY ON YUCATAN SLOPE CORES A Thesis by Mary Elizabeth Exner Approved as to style and content by: (Chairman of ommittee) , 1 (Head of Department)' p (Member ) (Member) August, 1972 gg...

  13. Star cell type core configuration for structural sandwich materials

    DOE Patents [OSTI]

    Christensen, R.M.

    1995-08-01

    A new pattern for cellular core material used in sandwich type structural materials is disclosed. The new pattern involves star shaped cells intermixed with hexagonal shaped cells. The new patterned cellular core material includes star shaped cells interconnected at points thereof and having hexagonal shape cells positioned adjacent the star points. The new pattern allows more flexibility and can conform more easily to curved shapes. 3 figs.

  14. Rotary mode core sampling approved checklist: 241-TX-113

    SciTech Connect (OSTI)

    Fowler, K.D.

    1998-08-03

    The safety assessment for rotary mode core sampling was developed using certain bounding assumptions, however, those assumptions were not verified for each of the existing or potential flammable gas tanks. Therefore, a Flammable Gas/Rotary Mode Core Sampling Approved Checklist has been completed for tank 241-TX-113 prior to sampling operations. This transmittal documents the dispositions of the checklist items from the safety assessment.

  15. Rotary mode core sampling approved checklist: 241-TX-116

    SciTech Connect (OSTI)

    FOWLER, K.D.

    1999-02-24

    The safety assessment for rotary mode core sampling was developed using certain bounding assumptions, however, those assumptions were not verified for each of the existing or potential flammable gas tanks. Therefore, a Flammable Gas/Rotary Mode Core Sampling Approved Checklist has been completed for tank 241-TX-116 prior to sampling operations. This transmittal documents the dispositions of the checklist items from the safety assessment.

  16. Chandra Imaging of the X-ray Core of the Virgo Cluster

    E-Print Network [OSTI]

    A. J. Young; A. S. Wilson; C. G. Mundell

    2002-07-15

    We report sub-arcsecond X-ray imaging spectroscopy of M87 and the core of the Virgo cluster with the Chandra X-ray Observatory. The X-ray morphology shows structure on arcsecond (~100 pc) to ten arcminute (~50 kpc) scales, the most prominent feature being an "arc" running from the east, across the central region of M87 and off to the southwest. A ridge in the radio map, ending in an "ear"-shaped structure, follows the arc to the east. Depressions in the X-ray surface brightness correspond to the inner radio lobes and there is no evidence of shock-heated gas surrounding them. There are also at least two approximately circular (centered near the nucleus) "edges" in the X-ray brightness distribution, the radii of which are slightly larger than the nuclear distances of the inner radio lobes and intermediate radio ridges, respectively. We speculate that these discontinuities may be spherical pulses or "fronts" driven by the same jet activity as is responsible for the radio structure; such pulses are found in recent numerical simulations. All these results provide good evidence that the nuclear activity affects the intra-cluster medium. We present a temperature map of the intra-cluster medium, and obtain the temperature, pressure and cooling time as a function of nuclear distance for the arcs and the ambient intra-cluster medium. We show that the gas in the arcs is cooler than, and probably over-pressured with respect to, the ambient intra-cluster medium. The metal abundances of the cooler gas in the arc are somewhat enhanced relative to the ambient intra-cluster medium, favoring a ``buoyant plume'' origin for the X-ray arc, in which ambient gas near the nucleus is entrained by buoyant radio plasma and carried to larger nuclear distances. (Abstract truncated).

  17. MULTI-DIMENSIONAL FEATURES OF NEUTRINO TRANSFER IN CORE-COLLAPSE SUPERNOVAE

    SciTech Connect (OSTI)

    Sumiyoshi, K. [Numazu College of Technology, Ooka 3600, Numazu, Shizuoka 410-8501 (Japan); Takiwaki, T. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Matsufuru, H. [Computing Research Center, High Energy Accelerator Research Organization 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Yamada, S., E-mail: sumi@numazu-ct.ac.jp, E-mail: takiwaki.tomoya@nao.ac.jp, E-mail: hideo.matsufuru@kek.jp, E-mail: shoichi@heap.phys.waseda.ac.jp [Science and Engineering and Advanced Research Institute for Science and Engineering, Waseda University, Okubo, 3-4-1, Shinjuku, Tokyo 169-8555 (Japan)

    2015-01-01

    We study the multi-dimensional properties of neutrino transfer inside supernova cores by solving the Boltzmann equations for neutrino distribution functions in genuinely six-dimensional phase space. Adopting representative snapshots of the post-bounce core from other supernova simulations in three dimensions, we solve the temporal evolution to stationary states of neutrino distribution functions using our Boltzmann solver. Taking advantage of the multi-angle and multi-energy feature realized by the S {sub n} method in our code, we reveal the genuine characteristics of spatially three-dimensional neutrino transfer, such as nonradial fluxes and nondiagonal Eddington tensors. In addition, we assess the ray-by-ray approximation, turning off the lateral-transport terms in our code. We demonstrate that the ray-by-ray approximation tends to propagate fluctuations in thermodynamical states around the neutrino sphere along each radial ray and overestimate the variations between the neutrino distributions on different radial rays. We find that the difference in the densities and fluxes of neutrinos between the ray-by-ray approximation and the full Boltzmann transport becomes ?20%, which is also the case for the local heating rate, whereas the volume-integrated heating rate in the Boltzmann transport is found to be only slightly larger (?2%) than the counterpart in the ray-by-ray approximation due to cancellation among different rays. These results suggest that we should carefully assess the possible influences of various approximations in the neutrino transfer employed in current simulations of supernova dynamics. Detailed information on the angle and energy moments of neutrino distribution functions will be profitable for the future development of numerical methods in neutrino-radiation hydrodynamics.

  18. VLBI Imaging of Luminous Infrared Galaxies: AGN Cores in Mrk231, UGC 5101 & NGC 7469

    E-Print Network [OSTI]

    Carol J. Lonsdale; Colin J. Lonsdale; Harding E. Smith; Philip J. Diamond

    2003-04-17

    We report 18cm VLBI continuum imaging observations at 5 mas resolution for UGC 5101, NGC 7469, and Mrk 231, all part of a sample of Luminous Infrared Galaxies which have been shown to have strong VLBI radio cores. The radio morphology of these three systems on VLBI scales is AGN-like, with well-defined ridgelines and high-brightness yet spatially resolved components. The structure and flux densities of these VLBI components are not consistent with starburst generated radio supernovae of the type found in Arp 220. On scales of 100pc the radio continuum in all three objects appears to be dominated by an AGN, not a starburst. Radio emission on larger scales may well originate in a less compact circumnuclear star-forming region. Confirming and extending VLBI imaging of Mrk 231 by Ulvestad et al. (1999), our continuum image shows a triple structure, with a core and two lobes, classifying it as a Compact Symmetric Object (CS0). If the southern (primary) lobe/hot-spot in Mrk 231 is confined by ram pressure, we estimate a lobe advance speed, $v_a \\sim 10^{-4}c$, and an age for the jet/compact source, $< 10^6 yr$. We have also imaged the 1667 MHz OH maser emission in Mrk 231, which is extended on scales of 50--100 milliarcsec (40--80 pc) and probably coincides with the inner region of the disk which is seen in CO emission and HI absorption. Among OH megamasers studied at high sensitivity with mas resolution, Mrk 231 is unique in the stringent upper limits placed upon the flux density of compact OH structures of the type found in Arp 220 and other LIGs. It is possible that the circumnuclear environment of Mrk 231 has been sufficiently disrupted by the emergent QSO that the cool, dense clouds necessary for such compact masers no longer exist.

  19. OS and Runtime Support for Efficiently Managing Cores in Parallel Applications

    E-Print Network [OSTI]

    Klues, Kevin Alan

    2015-01-01

    Composing parallel software efficiently with lithe. ” In:Runtime Support for Efficiently Managing Cores in ParallelRuntime Support for Efficiently Managing Cores in Parallel

  20. Comparative genomics of the core and accessory genomes of 48 Sinorhizobium strains comprising five genospecies

    E-Print Network [OSTI]

    2013-01-01

    annotation and comparative genomics. Database (Oxford) 2009,et al. : Comparative genomics of the core and accessoryComparative genomics of the core and accessory genomes of 48

  1. ESPP Functional Genomics and Imaging Core: Cell wide analysis of Metal-Reducing Bacteria

    E-Print Network [OSTI]

    Mukhopadhyay, Aindrila

    2014-01-01

    and Environmental Research, Genomics:GTL Program throughESPP Functional Genomics and Imaging Core: Cell widemetals. The Functional Genomics and Imaging Core (FGIC)

  2. Efficiency of static core turn-off in a system-on-a-chip with variation

    DOE Patents [OSTI]

    Cher, Chen-Yong; Coteus, Paul W; Gara, Alan; Kursun, Eren; Paulsen, David P; Schuelke, Brian A; Sheets, II, John E; Tian, Shurong

    2013-10-29

    A processor-implemented method for improving efficiency of a static core turn-off in a multi-core processor with variation, the method comprising: conducting via a simulation a turn-off analysis of the multi-core processor at the multi-core processor's design stage, wherein the turn-off analysis of the multi-core processor at the multi-core processor's design stage includes a first output corresponding to a first multi-core processor core to turn off; conducting a turn-off analysis of the multi-core processor at the multi-core processor's testing stage, wherein the turn-off analysis of the multi-core processor at the multi-core processor's testing stage includes a second output corresponding to a second multi-core processor core to turn off; comparing the first output and the second output to determine if the first output is referring to the same core to turn off as the second output; outputting a third output corresponding to the first multi-core processor core if the first output and the second output are both referring to the same core to turn off.

  3. Partial Safety Analysis for a Reduced Uranium Enrichment Core for the High Flux Isotope Reactor

    SciTech Connect (OSTI)

    Primm, Trent [ORNL; Gehin, Jess C [ORNL

    2009-04-01

    A computational model of the reactor core of the High Flux Isotope Rector (HFIR) was developed in order to analyze non-destructive accidents caused by transients during reactor operation. The reactor model was built for the latest version of the nuclear analysis software package called Program for the Analysis of Reactor Transients (PARET). Analyses performed with the model constructed were compared with previous data obtained with other tools in order to benchmark the code. Finally, the model was used to analyze the behavior of the reactor under transients using a different nuclear fuel with lower enrichment of uranium (LEU) than the fuel currently used, which has a high enrichment of uranium (HEU). The study shows that the presence of fertile isotopes in LEU fuel, which increases the neutron resonance absorption, reduces the impact of transients on the fuel and enhances the negative reactivity feedback, thus, within the limitations of this study, making LEU fuel appear to be a safe alternative fuel for the reactor core.

  4. Possible Methods to Estimate Core Location in a Beyond-Design-Basis Accident at a GE BWR with a Mark I Containment Stucture

    SciTech Connect (OSTI)

    Walston, S; Rowland, M; Campbell, K

    2011-07-27

    It is difficult to track to the location of a melted core in a GE BWR with Mark I containment during a beyond-design-basis accident. The Cooper Nuclear Station provided a baseline of normal material distributions and shielding configurations for the GE BWR with Mark I containment. Starting with source terms for a design-basis accident, methods and remote observation points were investigated to allow tracking of a melted core during a beyond-design-basis accident. The design of the GE BWR with Mark-I containment highlights an amazing poverty of expectations regarding a common mode failure of all reactor core cooling systems resulting in a beyond-design-basis accident from the simple loss of electric power. This design is shown in Figure 1. The station blackout accident scenario has been consistently identified as the leading contributor to calculated probabilities for core damage. While NRC-approved models and calculations provide guidance for indirect methods to assess core damage during a beyond-design-basis loss-of-coolant accident (LOCA), there appears to be no established method to track the location of the core directly should the LOCA include a degree of fuel melt. We came to the conclusion that - starting with detailed calculations which estimate the release and movement of gaseous and soluble fission products from the fuel - selected dose readings in specific rooms of the reactor building should allow the location of the core to be verified.

  5. Vertically aligned P(VDF-TrFE) core-shell structures on flexible pillar arrays

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

    Choi, Yoon-Young; Yun, Tae Gwang; Qaiser, Nadeem; Paik, Haemin; Roh, Hee Seok; Hong, Jongin; Hong, Seungbum; Han, Seung Min; No, Kwangsoo

    2015-06-04

    PVDF and P(VDF-TrFE) nano- and micro- structures are widely used due to their potential applications in several fields, including sensors, actuators, vital sign transducers, and energy harvesters. In this study, we developed vertically aligned P(VDF-TrFE) core-shell structures using high modulus polyurethane acrylate (PUA) pillars as the support structure to maintain the structural integrity. In addition, we were able to improve the piezoelectric effect by 1.85 times from 40 ± 2 to 74 ± 2 pm/V when compared to the thin film counterpart, which contributes to the more efficient current generation under a given stress, by making an effective use ofmore »the P(VDF-TrFE) thin top layer as well as the side walls. We attribute the enhancement of piezoelectric effects to the contributions from the shell component and the strain confinement effect, which was supported by our modeling results. We envision that these organic-based P(VDF-TrFE) core-shell structures will be used widely as 3D sensors and power generators because they are optimized for current generations by utilizing all surface areas, including the side walls of core-shell structures.« less

  6. THREE-DIMENSIONAL BOLTZMANN HYDRO CODE FOR CORE COLLAPSE IN MASSIVE STARS. I. SPECIAL RELATIVISTIC TREATMENTS

    SciTech Connect (OSTI)

    Nagakura, Hiroki [Yukawa Institute for Theoretical Physics, Kyoto University, Oiwake-cho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan); Sumiyoshi, Kohsuke [Numazu College of Technology, Ooka 3600, Numazu, Shizuoka 410-8501 (Japan); Yamada, Shoichi [Advanced Research Institute for Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555 (Japan)

    2014-10-01

    We propose a novel numerical method for solving multi-dimensional, special relativistic Boltzmann equations for neutrinos coupled with hydrodynamics equations. This method is meant to be applied to simulations of core-collapse supernovae. We handle special relativity in a non-conventional way, taking account of all orders of v/c. Consistent treatment of the advection and collision terms in the Boltzmann equations has been a challenge, which we overcome by employing two different energy grids: Lagrangian remapped and laboratory fixed grids. We conduct a series of basic tests and perform a one-dimensional simulation of core-collapse, bounce, and shock-stall for a 15 M {sub ?} progenitor model with a minimum but essential set of microphysics. We demonstrate in the latter simulation that our new code is capable of handling all phases in core-collapse supernova. For comparison, a non-relativistic simulation is also conducted with the same code, and we show that they produce qualitatively wrong results in neutrino transfer. Finally, we discuss a possible incorporation of general relativistic effects into our method.

  7. Development of Yangbajing Air shower Core detector array for a new EAS hybrid Experiment

    E-Print Network [OSTI]

    Liu, Jinsheng; Chen, Ding; Zhang, Ying; Zhai, Liuming; Chen, Xu; Hu, Xiaobin; Lin, Yuhui; Zhang, Xueyao; Feng, Cunfeng; Jia, Huanyu; Zhou, Xunxiu; DanZengLuoBu,; Chen, Tianlu; Li, Haijin; Liu, Maoyuan; Yuan, Aifang

    2015-01-01

    Aiming at the observation of cosmic-ray chemical composition at the "knee" energy region, we have been developinga new type air-shower core detector (YAC, Yangbajing Air shower Core detector array) to be set up at Yangbajing (90.522$^\\circ$ E, 30.102$^\\circ$ N, 4300 m above sea level, atmospheric depth: 606 g/m$^2$) in Tibet, China. YAC works together with the Tibet air-shower array (Tibet-III) and an underground water cherenkov muon detector array (MD) as a hybrid experiment. Each YAC detector unit consists of lead plates of 3.5 cm thick and a scintillation counter which detects the burst size induced by high energy particles in the air-shower cores. The burst size can be measured from 1 MIP (Minimum Ionization Particle) to $10^{6}$ MIPs. The first phase of this experiment, named "YAC-I", consists of 16 YAC detectors each having the size 40 cm $\\times$ 50 cm and distributing in a grid with an effective area of 10 m$^{2}$. YAC-I is used to check hadronic interaction models. The second phase of the experiment,...

  8. Properties of Starless and Prestellar Cores in Taurus Revealed by Herschel SPIRE/PACS Imaging

    E-Print Network [OSTI]

    Marsh, K A; Palmeirim, P; André, Ph; Kirk, J; Stamatellos, D; Ward-Thompson, D; Roy, A; Bontemps, S; Di Francesco, J; Elia, D; Hill, T; Konyves, V; Motte, F; Nguyen-Luong, Q; Peretto, N; Pezzuto, S; Rivera-Ingraham, A; Schneider, N; Spinoglio, L; White, G

    2014-01-01

    The density and temperature structures of dense cores in the L1495 cloud of the Taurus star-forming region are investigated using Herschel SPIRE and PACS images in the 70 $\\mu$m, 160 $\\mu$m, 250 $\\mu$m, 350 $\\mu$m and 500 $\\mu$m continuum bands. A sample consisting of 20 cores, selected using spectral and spatial criteria, is analysed using a new maximum likelihood technique, COREFIT, which takes full account of the instrumental point spread functions. We obtain central dust temperatures, $T_0$, in the range 6-12 K and find that, in the majority of cases, the radial density falloff at large radial distances is consistent with the $r^{-2}$ variation expected for Bonnor-Ebert spheres. Two of our cores exhibit a significantly steeper falloff, however, and since both appear to be gravitationally unstable, such behaviour may have implications for collapse models. We find a strong negative correlation between $T_0$ and peak column density, as expected if the dust is heated predominantly by the interstellar radiatio...

  9. Tank 241-TX-118, core 236 analytical results for the final report

    SciTech Connect (OSTI)

    ESCH, R.A.

    1998-11-19

    This document is the analytical laboratory report for tank 241-TX-118 push mode core segments collected between April 1, 1998 and April 13, 1998. The segments were subsampled and analyzed in accordance with the Tank 241-TX-118 Push Mode Core sampling and Analysis Plan (TSAP) (Benar, 1997), the Safety Screening Data Quality Objective (DQO) (Dukelow, et al., 1995), the Data Quality Objective to Support Resolution of the Organic Complexant Safety Issue (Organic DQO) (Turner, et al, 1995) and the Historical Model Evaluation Data Requirements (Historical DQO) (Sipson, et al., 1995). The analytical results are included in the data summary table (Table 1). None of the samples submitted for Differential Scanning Calorimetry (DSC) and Total Organic Carbon (TOC) exceeded notification limits as stated in the TSAP (Benar, 1997). One sample exceeded the Total Alpha Activity (AT) analysis notification limit of 38.4{micro}Ci/g (based on a bulk density of 1.6), core 236 segment 1 lower half solids (S98T001524). Appropriate notifications were made. Plutonium 239/240 analysis was requested as a secondary analysis. The statistical results of the 95% confidence interval on the mean calculations are provided by the Tank Waste Remediation Systems Technical Basis Group in accordance with the Memorandum of Understanding (Schreiber, 1997) and are not considered in this report.

  10. Category:Core Analysis | 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 Home Page on QA:QA J-E-1 SECTION JEnvironmentalBowerbank,Cammack Village,8199089°,Analytical ModelingInformation

  11. High Density n-Si/n-TiO2 Core/Shell Nanowire Arrays with Enhanced Photoactivity

    SciTech Connect (OSTI)

    Hwang, Yun Jeong; Boukai, Akram; Yang, Peidong

    2008-11-15

    There are currently great needs to develop low-cost inorganic materials that can efficiently perform solar water splitting as photoelectrolysis of water into hydrogen and oxygen has significant potential to provide clean energy. We investigate the Si/TiO2 nanowire heterostructures to determine their potential for the photooxidation of water. We observed that highly dense Si/TiO2 core/shell nanowire arrays enhanced the photocurrent by 2.5 times compared to planar Si/TiO2 structure due to their low reflectance and high surface area. We also showed that n-Si/n-TiO2 nanowire arrays exhibited a larger photocurrent and open circuit voltage than p-Si/n-TiO2 nanowires due to a barrier at the heterojunction.

  12. LMFBR in-core thermal-hydraulics: the state of the art and US research and development needs

    SciTech Connect (OSTI)

    Khan, E.U.

    1980-04-01

    A detailed critical review is presented of the literature relevant to predicting coolant flow and temperature fields in LMFBR core assemblies for nominal and non-nominal rod bundle geometries and reactor operating conditions. The review covers existing thermal-hydraulic models, computational methods, and experimental data useful for the design of an LMFBR core. The literature search made for this review included publications listed by Nuclear Science Abstracts and Energy Data Base as well as papers presented at key nuclear conferences. Based on this extensive review, the report discusses the accuracy with which the models predict flow and temperature fields in rod assemblies, identifying areas where analytical, experimental, and model development needs exist.

  13. Laboratory studies evaluating CO2 flood impact on the geomechanics of whole core samples

    SciTech Connect (OSTI)

    O'Connor, William K.

    2005-06-01

    Geological sequestration of CO2, whether by enhanced oil recovery (EOR), coal-bed methane (CBM) recovery, or saline aquifer injection is a promising near-term sequestration methodology. While tremendous experience exists for EOR, and CBM recovery has been demonstrated in existing fields, saline aquifer injection studies have only recently been initiated. Studies evaluating the availability of saline aquifers suitable for CO2 injection show great potential, however, the long-term fate of the injected CO2 in these ancient aqueous systems is still uncertain. Migration of the CO2 beyond the natural reservoir seals could become problematic, thus the identification of means to enhance the natural seals may help lead to the utilization of this sequestration methodology. Co-injection of a mineral reactant slurry, either with the CO2 or in separate, secondary injection wells, could provide a means to enhance the natural reservoir seals by providing the necessary cations for precipitation of mineral carbonates along the periphery of the injection plume. The subject study evaluates the merit of several mineral slurry co-injection strategies, by conduct of a series of laboratory-scale CO2 flood tests on whole core samples of the Mt. Simon sandstone from the Illinois Basin. By conducting these tests on whole core samples rather than crushed core, an evaluation of the impact of the CO2 flood on the rock mechanics properties as well as the geochemistry of the core and brine solution has been possible. This empirical data could provide a valuable resource for the validation of reservoir models under development for these engineered CO2 systems.

  14. TRIGGERING COLLAPSE OF THE PRESOLAR DENSE CLOUD CORE AND INJECTING SHORT-LIVED RADIOISOTOPES WITH A SHOCK WAVE. II. VARIED SHOCK WAVE AND CLOUD CORE PARAMETERS

    SciTech Connect (OSTI)

    Boss, Alan P.; Keiser, Sandra A. E-mail: keiser@dtm.ciw.edu

    2013-06-10

    A variety of stellar sources have been proposed for the origin of the short-lived radioisotopes that existed at the time of the formation of the earliest solar system solids, including Type II supernovae (SNe), asymptotic giant branch (AGB) and super-AGB stars, and Wolf-Rayet star winds. Our previous adaptive mesh hydrodynamics models with the FLASH2.5 code have shown which combinations of shock wave parameters are able to simultaneously trigger the gravitational collapse of a target dense cloud core and inject significant amounts of shock wave gas and dust, showing that thin SN shocks may be uniquely suited for the task. However, recent meteoritical studies have weakened the case for a direct SN injection to the presolar cloud, motivating us to re-examine a wider range of shock wave and cloud core parameters, including rotation, in order to better estimate the injection efficiencies for a variety of stellar sources. We find that SN shocks remain as the most promising stellar source, though planetary nebulae resulting from AGB star evolution cannot be conclusively ruled out. Wolf-Rayet (WR) star winds, however, are likely to lead to cloud core shredding, rather than to collapse. Injection efficiencies can be increased when the cloud is rotating about an axis aligned with the direction of the shock wave, by as much as a factor of {approx}10. The amount of gas and dust accreted from the post-shock wind can exceed that injected from the shock wave, with implications for the isotopic abundances expected for a SN source.

  15. COLLAPSE AND FRAGMENTATION OF MAGNETIC MOLECULAR CLOUD CORES WITH THE ENZO AMR MHD CODE. I. UNIFORM DENSITY SPHERES

    SciTech Connect (OSTI)

    Boss, Alan P.; Keiser, Sandra A.

    2013-02-20

    Magnetic fields are important contributors to the dynamics of collapsing molecular cloud cores, and can have a major effect on whether collapse results in a single protostar or fragmentation into a binary or multiple protostar system. New models are presented of the collapse of magnetic cloud cores using the adaptive mesh refinement code Enzo2.0. The code was used to calculate the ideal magnetohydrodynamics (MHD) of initially spherical, uniform density, and rotation clouds with density perturbations, i.e., the Boss and Bodenheimer standard isothermal test case for three-dimensional (3D) hydrodynamics codes. After first verifying that Enzo reproduces the binary fragmentation expected for the non-magnetic test case, a large set of models was computed with varied initial magnetic field strengths and directions with respect to the cloud core axis of rotation (parallel or perpendicular), density perturbation amplitudes, and equations of state. Three significantly different outcomes resulted: (1) contraction without sustained collapse, forming a denser cloud core; (2) collapse to form a single protostar with significant spiral arms; and (3) collapse and fragmentation into binary or multiple protostar systems, with multiple spiral arms. Comparisons are also made with previous MHD calculations of similar clouds with a barotropic equations of state. These results for the collapse of initially uniform density spheres illustrate the central importance of both magnetic field direction and field strength for determining the outcome of dynamic protostellar collapse.

  16. Evaluation of the Start-Up Core Physics Tests at Japan's High Temperature Engineering Test Reactor (Annular Core Loadings)

    SciTech Connect (OSTI)

    John D. Bess; Nozomu Fujimoto; James W. Sterbentz; Luka Snoj; Atsushi Zukeran

    2010-03-01

    The High Temperature Engineering Test Reactor (HTTR) of the Japan Atomic Energy Agency (JAEA) is a 30 MWth, graphite-moderated, helium-cooled reactor that was constructed with the objectives to establish and upgrade the technological basis for advanced high-temperature gas-cooled reactors (HTGRs) as well as to conduct various irradiation tests for innovative high-temperature research. The core size of the HTTR represents about one-half of that of future HTGRs, and the high excess reactivity of the HTTR, necessary for compensation of temperature, xenon, and burnup effects during power operations, is similar to that of future HTGRs. During the start-up core physics tests of the HTTR, various annular cores were formed to provide experimental data for verification of design codes for future HTGRs. The Japanese government approved construction of the HTTR in the 1989 fiscal year budget; construction began at the Oarai Research and Development Center in March 1991 and was completed May 1996. Fuel loading began July 1, 1998, from the core periphery. The first criticality was attained with an annular core on November 10, 1998 at 14:18, followed by a series of start-up core physics tests until a fully-loaded core was developed on December 16, 1998. Criticality tests were carried out into January 1999. The first full power operation with an average core outlet temperature of 850ºC was completed on December 7, 2001, and operational licensing of the HTTR was approved on March 6, 2002. The HTTR attained high temperature operation at 950 ºC in April 19, 2004. After a series of safety demonstration tests, it will be used as the heat source in a hydrogen production system by 2015. Hot zero-power critical, rise-to-power, irradiation, and safety demonstration testing , have also been performed with the HTTR, representing additional means for computational validation efforts. Power tests were performed in steps from 0 to 30 MW, with various tests performed at each step to confirm core characteristics, thermal-hydraulic properties, and radiation shielding. The high-temperature test operation at 950 ºC represented the fifth and final phase of the rise-to-power tests. The safety tests demonstrated inherent safety features of the HTTR such as slow temperature response during abnormal events due to the large heat capacity of the core and the negative reactivity feedback. The experimental benchmark performed and currently evaluated in this report pertains to the data available for the annular core criticals from the initial six isothermal, annular and fully-loaded, core critical measurements performed at the HTTR. Evaluation of the start-up core physics tests specific to the fully-loaded core is compiled elsewhere (HTTR-GCR-RESR-001).

  17. Hanging core support system for a nuclear reactor

    DOE Patents [OSTI]

    Burelbach, James P. (Glen Ellyn, IL); Kann, William J. (Park Ridge, IL); Pan, Yen-Cheng (Naperville, IL); Saiveau, James G. (Hickory Hills, IL); Seidensticker, Ralph W. (Wheaton, IL)

    1987-01-01

    For holding the reactor core in the confining reactor vessel, a support is disclosed that is structurally independent of the vessel, that is dimensionally accurate and stable, and that comprises tandem tension linkages that act redundantly of one another to maintain stabilized core support even in the unlikely event of the complete failure of one of the linkages. The core support has a mounting platform for the reactor core, and unitary structure including a flange overlying the top edge of the reactor vessels, and a skirt and box beams between the flange and platform for establishing one of the linkages. A plurality of tension rods connect between the deck closing the reactor vessel and the platform for establishing the redundant linkage. Loaded Belleville springs flexibly hold the tension rods at the deck and separable bayonet-type connections hold the tension rods at the platform. Motion or radiation sensing detectors can be provide at the lower ends of the tension rods for obtaining pertinent readings proximate the core.

  18. Position-sensitive fission counter for in-core flux profile monitoring

    SciTech Connect (OSTI)

    Kopp, M.K.; Valentine, K.H.; Guerrant, G.C.; Harter, J.A.

    1983-01-01

    A prototype model of a position-sensitive fission counter (PSFC) was developed for power-range flux profile monitoring in light-water reactor cores. The flux profile is measured by delay-line position encoding and time interval decoding of individual fission pulses from 11 small fission counters incorporated along a coaxial transmission line. Significant improvements over currently used flux profile monitors are the 33-cm spatial resolution of the 3.5-m-long PSFC and the requirement for only one cable penetration into the reactor pressure vessel.

  19. MNSR transient analyses and thermal hydraulic safety margins for HEU and LEU cores using the RELAP5-3D code

    SciTech Connect (OSTI)

    Dunn, F.E.; Thomas, J.; Liaw, J.; Matos, J.E. [RERTR Program, Argonne National Laboratory, Argonne, IL 60439 (United States)

    2008-07-15

    For safety analyses to support conversion of MNSR reactors from HEU fuel to LEU fuel, a RELAP5-3D model was set up to simulate the entire MNSR system. This model includes the core, the beryllium reflectors, the water in the tank and the water in the surrounding pool. The MCNP code was used to obtain the power distributions in the core and to obtain reactivity feedback coefficients for the transient analyses. The RELAP5-3D model was validated by comparing measured and calculated data for the NIRR-1 reactor in Nigeria. Comparisons include normal operation at constant power and a 3.77 mk rod withdrawal transient. Excellent agreement was obtained for core coolant inlet and outlet temperatures for operation at constant power, and for power level, coolant inlet temperature, and coolant outlet temperature for the rod withdrawal transient. In addition to the negative reactivity feedbacks from increasing core moderator and fuel temperatures, it was necessary to calculate and include positive reactivity feedback from temperature changes in the radial beryllium reflector and changes in the temperature and density of the water in the tank above the core and at the side of the core. The validated RELAP5-3D model was then used to analyze 3.77 mk rod withdrawal transients for LEU cores with two UO{sub 2} fuel pin designs. The impact of cracking of oxide LEU fuel is discussed. In addition, steady-state power operation at elevated power levels was evaluated to determine steady-state safety margins for onset of nucleate boiling and for onset of significant voiding. (author)

  20. DYNAMIC MODELING PROTON EXCHANGE MEMBRANE FUEL CELL

    E-Print Network [OSTI]

    Mease, Kenneth D.

    DYNAMIC MODELING PROTON EXCHANGE MEMBRANE FUEL CELL OVERVIEW Current/Completed Plug Power to garner SCAQMD funding for fuel cell testing GenCore system is sensitive to diluents · As built design stream to compensate for removal of EGR · Functionality of the modified GenCore Fuel Cell system