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Sample records for model results formats

  1. Motivation Model Results Summary A generative model for feedback networks

    E-Print Network [OSTI]

    White, Douglas R.

    Motivation Model Results Summary A generative model for feedback networks D.R. White1 N. Kejzar2 C #12;Motivation Model Results Summary Outline 1 Motivation An example 2 Model 3 Results Network properties Simulations #12;Motivation Model Results Summary Cycle formation in growing network How to model

  2. result formats | OpenEI Community

    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 IncIowa (UtilityMichigan)data bookresult formats Home Jweers's picture Submitted

  3. VALIDATION AND RESULTS OF A PSEUDO-MULTI-ZONE COMBUSTION TRAJECTORY PREDICTION MODEL FOR CAPTURING SOOT AND NOX FORMATION ON A MEDIUM DUTY DIESEL ENGINE

    SciTech Connect (OSTI)

    Bittle, Joshua A.; Gao, Zhiming; Jacobs, Timothy J.

    2013-01-01

    A pseudo-multi-zone phenomenological model has been created with the ultimate goal of supporting efforts to enable broader commercialization of low temperature combustion modes in diesel engines. The benefits of low temperature combustion are the simultaneous reduction in soot and nitric oxide emissions and increased engine efficiency if combustion is properly controlled. Determining what qualifies as low temperature combustion for any given engine can be difficult without expensive emissions analysis equipment. This determination can be made off-line using computer models or through factory calibration procedures. This process could potentially be simplified if a real-time prediction model could be implemented to run for any engine platform this is the motivation for this study. The major benefit of this model is the ability for it to predict the combustion trajectory, i.e. local temperature and equivalence ratio in the burning zones. The model successfully captures all the expected trends based on the experimental data and even highlights an opportunity for simply using the average reaction temperature and equivalence ratio as an indicator of emissions levels alone - without solving formation sub-models. This general type of modeling effort is not new, but a major effort was made to minimize the calculation duration to enable implementation as an input to real-time next-cycle engine controller Instead of simply using the predicted engine out soot and NOx levels, control decisions could be made based on the trajectory. This has the potential to save large amounts of calibration time because with minor tuning (the model has only one automatically determined constant) it is hoped that the control algorithm would be generally applicable.

  4. Structure formation: Models, Dynamics and Status

    E-Print Network [OSTI]

    T. Padmanabhan

    1995-08-25

    The constraints on the models for the structure formation arising from various cosmological observations at different length scales are reviewed. The status of different models for structure formation is examined critically in the light of these observations.

  5. 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...

  6. Autonomous Helicopter Formation using Model Predictive Control

    E-Print Network [OSTI]

    Sastry, S. Shankar

    Autonomous Helicopter Formation using Model Predictive Control Hoam Chung and S. Shankar Sastry for teams of helicopters. However, the potential for accidents is greatly increased when helicopter teams to the problem of helicopter formations comprised of heterogenous vehicles. The disturbance attenuation property

  7. Star Formation in Disk Galaxies. III. Does stellar feedback result in cloud death?

    E-Print Network [OSTI]

    Tasker, Elizabeth J; Pudritz, Ralph

    2015-01-01

    Stellar feedback, star formation and gravitational interactions are major controlling forces in the evolution of Giant Molecular Clouds (GMCs). To explore their relative roles, we examine the properties and evolution of GMCs forming in an isolated galactic disk simulation that includes both localised thermal feedback and photoelectric heating. The results are compared with the three previous simulations in this series which consists of a model with no star formation, star formation but no form of feedback and star formation with photoelectric heating in a set with steadily increasing physical effects. We find that the addition of localised thermal feedback greatly suppresses star formation but does not destroy the surrounding GMC, giving cloud properties closely resembling the run in which no stellar physics is included. The outflows from the feedback reduce the mass of the cloud but do not destroy it, allowing the cloud to survive its stellar children. This suggests that weak thermal feedback such as the low...

  8. The modelling of feedback in star formation simulations

    E-Print Network [OSTI]

    Dale, James E

    2015-01-01

    I review the current state of numerical simulations of stellar feedback in the context of star formation at scales ranging from the formation of individual stars to models of galaxy formation including cosmic reionisation. I survey the wealth of algorithms developed recently to solve the radiative transfer problem and to simulate stellar winds, supernovae and protostellar jets. I discuss the results of these simulations with regard to star formation in molecular clouds, the interaction of different feedback mechanisms with each other and with magnetic fields, and in the wider context of galactic-- and cosmological--scale simulations.

  9. Testing Disk Instability Models for Giant Planet Formation

    E-Print Network [OSTI]

    Alan P. Boss

    2007-04-09

    Disk instability is an attractive yet controversial means for the rapid formation of giant planets in our solar system and elsewhere. Recent concerns regarding the first adiabatic exponent of molecular hydrogen gas are addressed and shown not to lead to spurious clump formation in the author's disk instability models. A number of disk instability models have been calculated in order to further test the robustness of the mechanism, exploring the effects of changing the pressure equation of state, the vertical temperature profile, and other parameters affecting the temperature distribution. Possible reasons for differences in results obtained by other workers are discussed. Disk instability remains as a plausible formation mechanism for giant planets.

  10. UNIVERSITY OF CALGARY Modeling Fracture Formation on Growing Surfaces

    E-Print Network [OSTI]

    Prusinkiewicz, Przemyslaw

    UNIVERSITY OF CALGARY Modeling Fracture Formation on Growing Surfaces by Pavol Federl A THESIS Fracture Formation on Growing Surfaces" submitted by Pavol Federl in partial fulfillment This thesis describes a framework for modeling fracture formation on differentially growing, bi- layered

  11. Finite Element Model of Fracture Formation on Growing Surfaces

    E-Print Network [OSTI]

    Prusinkiewicz, Przemyslaw

    Finite Element Model of Fracture Formation on Growing Surfaces Pavol Federl and Przemyslaw-mail: federl|pwp@cpsc.ucalgary.ca Abstract We present a model of fracture formation on surfaces of bilayered materials. The model makes it possible to synthesize patterns of fractures induced by growth or shrinkage

  12. Modeling the formation of in vitro filopodia

    E-Print Network [OSTI]

    K. -C. Lee; A. Gopinathan; J. M. Schwarz

    2010-05-13

    Filopodia are bundles of actin filaments that extend out ahead of the leading edge of a crawling cell to probe its upcoming environment. {\\it In vitro} experiments [D. Vignjevic {\\it et al.}, J. Cell Biol. {\\bf 160}, 951 (2003)] have determined the minimal ingredients required for the formation of filopodia from the dendritic-like morphology of the leading edge. We model these experiments using kinetic aggregation equations for the density of growing bundle tips. In mean field, we determine the bundle size distribution to be broad for bundle sizes smaller than a characteristic bundle size above which the distribution decays exponentially. Two-dimensional simulations incorporating both bundling and cross-linking measure a bundle size distribution that agrees qualitatively with mean field. The simulations also demonstrate a nonmonotonicity in the radial extent of the dendritic region as a function of capping protein concentration, as was observed in experiments, due to the interplay between percolation and the ratcheting of growing filaments off a spherical obstacle.

  13. Modeling deposit formation in diesel injector nozzle

    E-Print Network [OSTI]

    Sudhiesh Kumar, Chintoo

    2009-01-01

    Formation of deposit in the diesel injector nozzle affects the injection behavior and hinders performance. Under running condition, deposit precursors are washed away by the ensuing injection. However, during the cool down ...

  14. Modelling and control of satellite formations 

    E-Print Network [OSTI]

    Vaddi, Veera Venkata Sesha Sai

    2004-09-30

    ®erent satellites in a formation. To achieve the various mission objectives it is necessary for a formation to recon¯gure itself periodically. An analytical impulsive control scheme has been developed for this purpose. This control scheme has the distinct advantage... . . . . . . . . . . . . . . . . . . 15 1.4.2 Impulsive Control . . . . . . . . . . . . . . . . . . . 16 1.5 Goals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 1.6 Nonlinearity and Eccentricity Perturbations . . . . . . . . 18 1.7 Linear and Nonlinear Controllers...

  15. Uncalibrated Building Energy Simulation Modeling Results 

    E-Print Network [OSTI]

    Ahmad, M.; Culp, C.H.

    2006-01-01

    &R RESEARCH OCTOBER 2006 1141 Uncalibrated Building Energy Simulation Modeling Results Mushtaq Ahmad Charles H. Culp, PhD, PE Associate Member ASHRAE Fellow ASHRAE Received June 23, 2005; accepted April 17, 2006 Uncalibrated simulations have provided useful... was to analyze the performance of four uncali- brated simulation models using DOE-2.1E Version 119 (Ayres and Stamper 1995) as the simula- tion package. The four buildings were randomly selected from a building data base (LoanSTAR 2005). Three of the four...

  16. Vegetated Roof Water-Balance Model: Experimental and Model Results

    E-Print Network [OSTI]

    Vegetated Roof Water-Balance Model: Experimental and Model Results James A. Sherrard Jr.1 and Jennifer M. Jacobs, M.ASCE2 Abstract: A five parameter, daily vegetated roof water balance model (VR-WBM) was developed, calibrated, and validated by using experimental vegetated roof data from the Seacoast, New

  17. MODELING OF POROSITY FORMATION AND FEEDING FLOW IN STEEL CASTING

    E-Print Network [OSTI]

    Beckermann, Christoph

    , or even larger shrinkage cavities found in inadequately fed cast sections. Microporosity can cause leaksMODELING OF POROSITY FORMATION AND FEEDING FLOW IN STEEL CASTING Kent D. Carlson, Zhiping Lin pressure, feeding flow, and porosity formation and growth in steel castings during solidification

  18. Quasi Light Fields: A Model of Coherent Image Formation

    E-Print Network [OSTI]

    Accardi, Anthony J.

    We develop a model of coherent image formation that strikes a balance between the simplicity of the light field and the comprehensive predictive power of Maxwell's equations, by extending the light field to coherent radiation.

  19. Modelling of reoxidation inclusion formation in steel sand casting

    E-Print Network [OSTI]

    Beckermann, Christoph

    Modelling of reoxidation inclusion formation in steel sand casting A. J. Melendez, K. D. Carlson pouring, as well as their final locations on the surface of steel sand castings. Inclusions originate. The inclusion model is implemented in a general-purpose casting simulation code. The model is validated

  20. Kinetic model for nitric oxide formation during pulverized coal combustion

    SciTech Connect (OSTI)

    Mitchell, J.W.; Tarbell, J.M.

    1982-03-01

    A mathematical model of NO formation during pulverised coal combustion was developed from a proposed kinetic mechanism involving 12 overall chemical reactions. Most significantly, the model describes the complex conversion of coal bound nitrogen compounds to NO during combustion. The predictions of the model compare favourably with literature data and are in qualitative agreement with trends observed in practical coal combustion.

  1. Exact Results for Supersymmetric Sigma Models

    E-Print Network [OSTI]

    S. Cecotti; C. Vafa

    1991-11-07

    We show that the metric and Berry's curvature for the ground states of $N=2$ supersymmetric sigma models can be computed exactly as one varies the Kahler structure. For the case of $CP^n$ these are related to special solutions of affine toda equations. This allows us to extract exact results (including exact instanton corrections). We find that the ground state metric is non-singular as the size of the manifold shrinks to zero thus suggesting that 2d QFT makes sense even beyond zero radius. In other words it seems that manifolds with zero size are non-singular as target spaces for string theory (even when they are not conformal). The cases of $CP^1$ and $CP^2$ are discussed in more detail.

  2. Halo Formation in Warm Dark Matter Models

    E-Print Network [OSTI]

    Paul Bode; Jeremiah P. Ostriker; Neil Turok

    2001-05-29

    Discrepancies have emerged between the predictions of standard cold dark matter (CDM) theory and observations of clustering on sub-galactic scales. Warm dark matter (WDM) is a simple modification of CDM in which the dark matter particles have initial velocities due either to their having decoupled as thermal relics, or having been formed via non-equilibrium decay. We investigate the nonlinear gravitational clustering of WDM with a high resolution N-body code, and identify a number of distinctive observational signatures. Relative to CDM, halo concentrations and core densities are lowered, core radii are increased, and large halos emerge with far fewer low mass satellites. The number of small halos is suppressed, and those present are formed by `top down' fragmentation of caustics, as part of a `cosmic web' connecting massive halos. Few small halos form outside this web. If we identify small halos with dwarf galaxies, their number, spatial distribution, and formation epoch appear in better agreement with the observations for WDM than they are for CDM.

  3. nIFTy Cosmology: Comparison of Galaxy Formation Models

    E-Print Network [OSTI]

    Knebe, Alexander; Thomas, Peter A; Benson, Andrew; Blaizot, Jeremy; Bower, Richard; Carretero, Jorge; Castander, Francisco J; Cattaneo, Andrea; Cora, Sofia A; Croton, Darren J; Cui, Weiguang; Cunnama, Daniel; De Lucia, Gabriella; Devriendt, Julien E; Elahi, Pascal J; Font, Andreea; Fontanot, Fabio; Garcia-Bellido, Juan; Gargiulo, Ignacio D; Gonzalez-Perez, Violeta; Helly, John; Henriques, Bruno; Hirschmann, Michaela; Lee, Jaehyun; Mamon, Gary A; Monaco, Pierluigi; Onions, Julian; Padilla, Nelson D; Power, Chris; Pujol, Arnau; Skibba, Ramin A; Somerville, Rachel S; Srisawat, Chaichalit; Vega-Martinez, Cristian A; Yi, Sukyoung K

    2015-01-01

    We present a comparison of 14 galaxy formation models: 12 different semi-analytical models and 2 halo-occupation distribution models for galaxy formation based upon the same cosmological simulation and merger tree information derived from it. The participating codes have proven to be very successful in their own right but they have all been calibrated independently using various observational data sets, stellar models, and merger trees. In this paper we apply them without recalibration and this leads to a wide variety of predictions for the stellar mass function, specific star formation rates, stellar-to- halo mass ratios, and the abundance of orphan galaxies. The scatter is much larger than seen in previous comparison studies primarily because the codes have been used outside of their native environment within which they are well tested and calibrated. The purpose of the `nIFTy comparison of galaxy formation models' is to bring together as many different galaxy formation modellers as possible and to investig...

  4. Viscoelastic damage modeling of sinkhole formation Eyal Shalev*, Vladimir Lyakhovsky

    E-Print Network [OSTI]

    Lyakhovsky, Vladimir

    Viscoelastic damage modeling of sinkhole formation Eyal Shalev*, Vladimir Lyakhovsky Geological 2012 Keywords: Sinkholes Damage Viscoelasticity Modeling a b s t r a c t The sinkholes along the Dead Sea coast are observed in two main sedimentary environments: alluvial fan sinkholes, which usually

  5. Structure formation in modified gravity models alternative to dark energy

    E-Print Network [OSTI]

    Kazuya Koyama

    2006-01-10

    We study structure formation in phenomenological models in which the Friedmann equation receives a correction of the form $H^{\\alpha}/r_c^{2-\\alpha}$, which realize an accelerated expansion without dark energy. In order to address structure formation in these model, we construct simple covariant gravitational equations which give the modified Friedmann equation with $\\alpha=2/n$ where $n$ is an integer. For $n=2$, the underlying theory is known as a 5D braneworld model (the DGP model). Thus the models interpolate between the DGP model ($n=2, \\alpha=1$) and the LCDM model in general relativity ($n \\to \\infty, \\alpha \\to 0$). Using the covariant equations, cosmological perturbations are analyzed. It is shown that in order to satisfy the Bianchi identity at a perturbative level, we need to introduce a correction term $E_{\\mu \

  6. Structure formation in modified gravity models alternative to dark energy

    E-Print Network [OSTI]

    Koyama, K

    2006-01-01

    We study structure formation in phenomenological models in which the Friedmann equation receives a correction of the form $H^{\\alpha}/r_c^{2-\\alpha}$, which realize an accelerated expansion without dark energy. In order to address structure formation in these model, we construct simple covariant gravitational equations which give the modified Friedmann equation with $\\alpha=2/n$ where $n$ is an integer. For $n=2$, the underlying theory is known as a 5D braneworld model (the DGP model). Thus the models interpolate between the DGP model ($n=2, \\alpha=1$) and the LCDM model in general relativity ($n \\to \\infty, \\alpha \\to 0$). Using the covariant equations, cosmological perturbations are analyzed. It is shown that in order to satisfy the Bianchi identity at a perturbative level, we need to introduce a correction term $E_{\\mu \

  7. COMPARING MODEL RESULTS TO NATIONAL CLIMATE POLICY GOALS: RESULTS FROM THE ASIA MODELING EXERCISE

    SciTech Connect (OSTI)

    Calvin, Katherine V.; Fawcett, Allen A.; Jiang, Kejun

    2012-12-01

    While the world has yet to adopt a single unified policy to limit climate change, many countries and regions have adopted energy and climate policies that have implications for global emissions. In this paper, we discuss a few key policies and how they are included in a set of 24 energy and integrated assessment models that participated in the Asia Modeling Exercise. We also compare results from these models for a small set of stylized scenarios to the pledges made as part of the Copenhagen Accord and the goals stated by the Major Economies Forum. We find that the targets outlined by the United States, the European Union, Japan, and Korea require significant policy action in most of the models analyzed. For most of the models in the study, however, the goals outlined by India are met without any climate policy. The stringency of climate policy required to meet China’s Copenhagen pledges varies across models and accounting methodologies.

  8. Modeling Coupled Processes in Clay Formations for Radioactive Waste Disposal

    SciTech Connect (OSTI)

    Liu, Hui-Hai; Rutqvist, Jonny; Zheng, Liange; Sonnenthal, Eric; Houseworth, Jim; Birkholzer, Jens

    2010-08-31

    As a result of the termination of the Yucca Mountain Project, the United States Department of Energy (DOE) has started to explore various alternative avenues for the disposition of used nuclear fuel and nuclear waste. The overall scope of the investigation includes temporary storage, transportation issues, permanent disposal, various nuclear fuel types, processing alternatives, and resulting waste streams. Although geologic disposal is not the only alternative, it is still the leading candidate for permanent disposal. The realm of geologic disposal also offers a range of geologic environments that may be considered, among those clay shale formations. Figure 1-1 presents the distribution of clay/shale formations within the USA. Clay rock/shale has been considered as potential host rock for geological disposal of high-level nuclear waste throughout the world, because of its low permeability, low diffusion coefficient, high retention capacity for radionuclides, and capability to self-seal fractures induced by tunnel excavation. For example, Callovo-Oxfordian argillites at the Bure site, France (Fouche et al., 2004), Toarcian argillites at the Tournemire site, France (Patriarche et al., 2004), Opalinus clay at the Mont Terri site, Switzerland (Meier et al., 2000), and Boom clay at Mol site, Belgium (Barnichon et al., 2005) have all been under intensive scientific investigations (at both field and laboratory scales) for understanding a variety of rock properties and their relations with flow and transport processes associated with geological disposal of nuclear waste. Clay/shale formations may be generally classified as indurated and plastic clays (Tsang et al., 2005). The latter (including Boom clay) is a softer material without high cohesion; its deformation is dominantly plastic. For both clay rocks, coupled thermal, hydrological, mechanical and chemical (THMC) processes are expected to have a significant impact on the long-term safety of a clay repository. For example, the excavation-damaged zone (EDZ) near repository tunnels can modify local permeability (resulting from induced fractures), potentially leading to less confinement capability (Tsang et al., 2005). Because of clay's swelling and shrinkage behavior (depending on whether the clay is in imbibition or drainage processes), fracture properties in the EDZ are quite dynamic and evolve over time as hydromechanical conditions change. To understand and model the coupled processes and their impact on repository performance is critical for the defensible performance assessment of a clay repository. Within the Natural Barrier System (NBS) group of the Used Fuel Disposition (UFD) Campaign at DOE's Office of Nuclear Energy, LBNL's research activities have focused on understanding and modeling such coupled processes. LBNL provided a report in this April on literature survey of studies on coupled processes in clay repositories and identification of technical issues and knowledge gaps (Tsang et al., 2010). This report will document other LBNL research activities within the natural system work package, including the development of constitutive relationships for elastic deformation of clay rock (Section 2), a THM modeling study (Section 3) and a THC modeling study (Section 4). The purpose of the THM and THC modeling studies is to demonstrate the current modeling capabilities in dealing with coupled processes in a potential clay repository. In Section 5, we discuss potential future R&D work based on the identified knowledge gaps. The linkage between these activities and related FEPs is presented in Section 6.

  9. Modeling and Field Results from Seismic Stimulation

    SciTech Connect (OSTI)

    Majer, E.; Pride, S.; Lo, W.; Daley, T.; Nakagawa, Seiji; Sposito, Garrison; Roberts, P.

    2006-05-30

    Modeling the effect of seismic stimulation employing Maxwell-Boltzmann theory shows that the important component of stimulation is mechanical rather than fluid pressure effects. Modeling using Biot theory (two phases) shows that the pressure effects diffuse too quickly to be of practical significance. Field data from actual stimulation will be shown to compare to theory.

  10. Galaxy formation history through hod model from euclid mock catalogs

    E-Print Network [OSTI]

    Sakr, Ziad

    2015-01-01

    Halo Occupation Distribution (HOD) is a model giving the average number of galaxies in a dark matter halo, function of its mass and other intrinsic properties, like distance from halo center, luminosity and redshift of its constituting galaxies. It is believed that these parameters could also be related to the galaxy history of formation. We want to investigate more this relation in order to test and better refine this model. To do that, we extract HOD indicators from EUCLID mock catalogs for different luminosity cuts and for redshifts ranges going from 0.1 formation history following the idea that galaxy evolution is the combination rather than the conflict of the two main proposed ideas nowadays: the older hierarchical mass merger driven paradigm and the recent downsizing star formation driven approach.

  11. A simple model of the hierarchical formation of galaxies

    E-Print Network [OSTI]

    B. Hoeneisen

    2000-09-05

    We develop a simple, fast and predictive model of the hierarchical formation of galaxies which is in quantitative agreement with observations. Comparing simulations with observations we place constraints on the density of the universe and on the power spectrum of density fluctuations.

  12. Modeling jet and outflow feedback during star cluster formation

    SciTech Connect (OSTI)

    Federrath, Christoph; Schrön, Martin; Banerjee, Robi; Klessen, Ralf S.

    2014-08-01

    Powerful jets and outflows are launched from the protostellar disks around newborn stars. These outflows carry enough mass and momentum to transform the structure of their parent molecular cloud and to potentially control star formation itself. Despite their importance, we have not been able to fully quantify the impact of jets and outflows during the formation of a star cluster. The main problem lies in limited computing power. We would have to resolve the magnetic jet-launching mechanism close to the protostar and at the same time follow the evolution of a parsec-size cloud for a million years. Current computer power and codes fall orders of magnitude short of achieving this. In order to overcome this problem, we implement a subgrid-scale (SGS) model for launching jets and outflows, which demonstrably converges and reproduces the mass, linear and angular momentum transfer, and the speed of real jets, with ?1000 times lower resolution than would be required without the SGS model. We apply the new SGS model to turbulent, magnetized star cluster formation and show that jets and outflows (1) eject about one-fourth of their parent molecular clump in high-speed jets, quickly reaching distances of more than a parsec, (2) reduce the star formation rate by about a factor of two, and (3) lead to the formation of ?1.5 times as many stars compared to the no-outflow case. Most importantly, we find that jets and outflows reduce the average star mass by a factor of ? three and may thus be essential for understanding the characteristic mass of the stellar initial mass function.

  13. Crystal Structure Representations for Machine Learning Models of Formation Energies

    E-Print Network [OSTI]

    Faber, Felix; von Lilienfeld, O Anatole; Armiento, Rickard

    2015-01-01

    We introduce and evaluate a set of feature vector representations of crystal structures for machine learning (ML) models of formation energies of solids. ML models of atomization energies of organic molecules have been successful using a Coulomb matrix representation of the molecule. We consider three ways to generalize such representations to periodic systems: (i) a matrix where each element is related to the Ewald sum of the electrostatic interaction between two different atoms in the unit cell repeated over the lattice; (ii) an extended Coulomb-like matrix that takes into account a number of neighboring unit cells; and (iii) an Ansatz that mimics the periodicity and the basic features of the elements in the Ewald sum matrix by using a sine function of the crystal coordinates of the atoms. The representations are compared for a Laplacian kernel with Manhattan norm, trained to reproduce formation energies using a data set of 3938 crystal structures obtained from the Materials Project. For training sets consi...

  14. Direct containment heating: Surtsey test results and models

    SciTech Connect (OSTI)

    Tarbell, W.W.; Nichols, R.T.; Pilch, M.; Brockmann, J.E.; Powers, D.A.

    1988-08-01

    Direct containment heating is one of the processes that can lead to containment rupture early in a severe reactor accident. The origins and the current understanding of this process are surveyed. Three issues arise in connection with direct containment heating -- threats to containment integrity posed by transfer of energy to the containment atmosphere from dispersed core debris or the generation of hydrogen by reactions of core debris with steam, and the formation of radioactive aerosols available for release from the plant should containment integrity be lost. The two threats to containment integrity have different characteristics. Energy exchange between core debris and the atmosphere depends on the long range dispersal of the debris and the atmosphere depends on the long range dispersal of the debris and can be affected by interactions of the debris with structures and co-dispersed water. Hydrogen generation is dependent on the detailed flows of debris and steam within and near the reactor cavity. Results of four experiments in the Surtsey test facility to explore energy exchange with the atmosphere are presented. These experiments suggest ''single particle'' models of direct heating over-predict the threat to containment integrity and that debris/structure interactions can enhance heating of the containment atmosphere. Results of test to establish the low pressure cut-off to direct heating are reported. 23 refs., 2 figs., 1 tab.

  15. Structure formation and CMBR anisotropy spectrum in the inflessence model

    E-Print Network [OSTI]

    A. A. Sen; V. F. Cardone; S. Capozziello; A. Troisi

    2006-07-25

    The inflessence model has recently been proposed in an attempt to explain both early inflation and present day accelerated expansion within a single mechanism. The model has been successfully tested against the Hubble diagram of Type Ia Supernovae, the shift parameter, and the acoustic peak parameter. As a further mandatory test, we investigate here structure formation in the inflessence model determining the evolution of matter density contrast $\\delta \\equiv \\delta \\rho_M/\\rho_M$ in the linear regime. We compare the growth factor $D(a) \\equiv \\delta/a$ and the growth index $f(z) \\equiv d\\ln{\\delta}/d\\ln{a}$ to these same quantities for the successful concordance $\\Lambda$CDM model with a particular emphasis on the role of the inflessence parameters $(\\gamma, z_Q)$. We also evaluate the anisotropy spectrum of the cosmic microwave background radiation (CMBR) to check whether the inflessence model may be in agreement with the observations. We find that, for large values of $(\\gamma, z_Q)$, structure formation proceeds in a similar way to that in the $\\Lambda$CDM scenario, and it is also possible to nicely fit the CMBR spectrum.

  16. Structure formation in inhomogeneous Early Dark Energy models

    SciTech Connect (OSTI)

    Batista, R.C. [Escola de Ciências e Tecnologia, Universidade Federal do Rio Grande do Norte, Caixa Postal 1524, 59072-970, Natal, Rio Grande do Norte (Brazil); Pace, F., E-mail: rbatista@ect.ufrn.br, E-mail: francesco.pace@port.ac.uk [Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Portsmouth, PO1 3FX (United Kingdom)

    2013-06-01

    We study the impact of Early Dark Energy fluctuations in the linear and non-linear regimes of structure formation. In these models the energy density of dark energy is non-negligible at high redshifts and the fluctuations in the dark energy component can have the same order of magnitude of dark matter fluctuations. Since two basic approximations usually taken in the standard scenario of quintessence models, that both dark energy density during the matter dominated period and dark energy fluctuations on small scales are negligible, are not valid in such models, we first study approximate analytical solutions for dark matter and dark energy perturbations in the linear regime. This study is helpful to find consistent initial conditions for the system of equations and to analytically understand the effects of Early Dark Energy and its fluctuations, which are also verified numerically. In the linear regime we compute the matter growth and variation of the gravitational potential associated with the Integrated Sachs-Wolf effect, showing that these observables present important modifications due to Early Dark Energy fluctuations, though making them more similar to the ?CDM model. We also make use of the Spherical Collapse model to study the influence of Early Dark Energy fluctuations in the nonlinear regime of structure formation, especially on ?{sub c} parameter, and their contribution to the halo mass, which we show can be of the order of 10%. We finally compute how the number density of halos is modified in comparison to the ?CDM model and address the problem of how to correct the mass function in order to take into account the contribution of clustered dark energy. We conclude that the inhomogeneous Early Dark Energy models are more similar to the ?CDM model than its homogeneous counterparts.

  17. MODELING AND SIMULATION OF FINGERING PATTERN FORMATION IN A COMBUSTION MODEL

    E-Print Network [OSTI]

    Shen, Jie

    MODELING AND SIMULATION OF FINGERING PATTERN FORMATION IN A COMBUSTION MODEL LINA HU, CLAUDE-MICHEL BRAUNER, JIE SHEN, AND GREGORY I. SIVASHINSKY Abstract. We consider a model of gas-solid combustion background. Combustion is basically a process of fast oxidation accompanied by substantial heat release

  18. Coalescence model for Theta_c pentaquark formation

    E-Print Network [OSTI]

    Marek Karliner; Bryan R. Webber

    2005-01-14

    We present a model for the formation of the charmed pentaquark Theta_c in hard scattering processes such as deep inelastic scattering, e^+e^- annihilation, and high-energy p pbar collisions. The model assumes that the cross section for Theta_c formation is proportional to the rate of production of p D^{*-} (or pbar D^{*+}) pairs in close proximity both in momentum space and in coordinate space. The constant of proportionality is determined from the Theta_c cross section in deep inelastic scattering as reported by the H1 experiment. The HERWIG Monte Carlo is used to generate simulated DIS events and also to model the space-time structure of the final state. Requiring the proton and the D^* be within a 100 MeV mass window and separated by a spacelike distance of no more than 2 fm, we find that a large "coalescence enhancement factor" F_co \\sim 10 is required to account for the H1 signal. The same approach is then applied in order to estimate the number and characteristics of Theta_c events produced at LEP and the Tevatron.

  19. Predictive modeling of synergistic effects in nanoscale ion track formation

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

    Zarkadoula, Eva; Pakarinen, Olli H.; Xue, Haizhou; Zhang, Yanwen; Weber, William J.

    2015-08-05

    Molecular dynamics techniques and the inelastic thermal spike model are used to study the coupled effects of inelastic energy loss due to 21 MeV Ni ion irradiation and pre-existing defects in SrTiO3. We determine the dependence on pre-existing defect concentration of nanoscale track formation occurring from the synergy between the inelastic energy loss and the pre-existing atomic defects. We show that the nanoscale ion tracks’ size can be controlled by the concentration of pre-existing disorder. This work identifies a major gap in fundamental understanding concerning the role played by defects in electronic energy dissipation and electron–lattice coupling.

  20. TOP-DOWN MODELING; PRACTICAL, FAST TRACK, RESERVOIR SIMULATION & MODELING FOR SHALE FORMATIONS Shahab D. Mohaghegh1 & Grant Bromhal2

    E-Print Network [OSTI]

    Mohaghegh, Shahab

    development in the oil and gas industry and is being used on some shale formations. BAKKEN SHALE MuchTOP-DOWN MODELING; PRACTICAL, FAST TRACK, RESERVOIR SIMULATION & MODELING FOR SHALE FORMATIONS based on measure data, called Top-Down, Intelligent Reservoir Modeling for the shale formations

  1. Results from Development of Model Specifications for Multifamily Energy Retrofits

    SciTech Connect (OSTI)

    Brozyna, K.

    2012-08-01

    Specifications, modeled after CSI MasterFormat, provide the trade contractors and builders with requirements and recommendations on specific building materials, components and industry practices that comply with the expectations and intent of the requirements within the various funding programs associated with a project. The goal is to create a greater level of consistency in execution of energy efficiency retrofits measures across the multiple regions a developer may work. IBACOS and Mercy Housing developed sample model specifications based on a common building construction type that Mercy Housing encounters.

  2. Results From Development of Model Specifications for Multifamily Energy Retrofits

    SciTech Connect (OSTI)

    Kevin Brozyna

    2012-08-01

    Specifications, modeled after CSI MasterFormat, provide the trade contractors and builders with requirements and recommendations on specific building materials, components and industry practices that comply with the expectations and intent of the requirements within the various funding programs associated with a project. The goal is to create a greater level of consistency in execution of energy efficiency retrofits measures across the multiple regions a developer may work. IBACOS and Mercy Housing developed sample model specifications based on a common building construction type that Mercy Housing encounters.

  3. Modelling the local and global cloud formation on HD 189733b

    E-Print Network [OSTI]

    Lee, G; Dobbs-Dixon, I; Juncher, D

    2015-01-01

    Context. Observations suggest that exoplanets such as HD 189733b form clouds in their atmospheres which have a strong feedback onto their thermodynamical and chemical structure, and overall appearance. Aims. Inspired by mineral cloud modelling efforts for Brown Dwarf atmospheres, we present the first spatially varying kinetic cloud model structures for HD 189733b. Methods. We apply a 2-model approach using results from a 3D global radiation-hydrodynamic simulation of the atmosphere as input for a detailed, kinetic cloud formation model. Sampling the 3D global atmosphere structure with 1D trajectories allows us to model the spatially varying cloud structure on HD 189733b. The resulting cloud properties enable the calculation of the scattering and absorption properties of the clouds. Results. We present local and global cloud structure and property maps for HD 189733b. The calculated cloud properties show variations in composition, size and number density of cloud particles which are strongest between the daysi...

  4. Sandia Energy - Results from the Human Resilience Index and Modeling...

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

    Results from the Human Resilience Index and Modeling project were reported recently in the National Intelligence Council's Global Trends 2030 Report Home Infrastructure Security...

  5. Exact results for models of multichannel quantum nonadiabatic...

    Office of Scientific and Technical Information (OSTI)

    Details In-Document Search This content will become publicly available on December 11, 2015 Title: Exact results for models of multichannel quantum nonadiabatic transitions...

  6. Experimental and modeling investigation of aromatic and polycyclic aromatic hydrocarbon formation in a premixed ethylene flame

    SciTech Connect (OSTI)

    Castaldi, M.J.; Marinov, N.M.; Melius, C.F.

    1996-02-01

    Experimental and detailed chemical kinetic modeling has been performed to investigate aromatic and polyaromatic hydrocarbon formation pathways in a rich, sooting, ethylene-oxygen-argon premixed flame. An atmospheric pressure, laminar flat flame operated at an equivalence ratio of 2.5 was used to acquire experimental data for model validation. Gas composition analysis was conducted by an on-line gas chromatograph/mass spectrometer (GC/MS) technique. Measurements were made in the flame and post-flame zone for a number of low molecular weight species, aliphatics, aromatics and polycyclic aromatic hydrocarbons (PAHs) ranging from two to five-aromatic fused rings. The modeling results show the key reaction sequences leading to aromatic and polycyclic aromatic hydrocarbon growth involve the combination of resonantly stabilized radicals. In particular, propargyl and 1-methylallenyl combination reactions lead to benzene and methyl substituted benzene formation, while polycyclic aromatics are formed from cyclopentadienyl radicals and fused rings that have a shared C{sub 5} side structure. Naphthalene production through the reaction step of cyclopentadienyl self-combination and phenanthrene formation from indenyl and cyclopentadienyl combination were shown to be important in the flame modeling study. The removal of phenyl by O{sub 2} leading to cyclopentadienyl formation is expected to play a pivotal role in the PAH or soot precursor growth process under fuel-rich oxidation conditions.

  7. First Structure Formation: I. Primordial Star Forming Regions in hierarchical models

    E-Print Network [OSTI]

    Tom Abel; Peter Anninos; Michael L. Norman; Yu Zhang

    1997-05-17

    We investigate the possibility of very early formation of primordial star clusters from high-\\sigma perturbations in cold dark matter dominated structure formation scenarios. For this we have developed a powerful 2-level hierarchical cosmological code with a realistic and robust treatment of multi-species primordial gas chemistry, paying special attention to the formation and destruction of hydrogen molecules, non-equilibrium ionization, and cooling processes. We performed 3-D simulations at small scales and at high redshifts and find that, analogous to simulations of large scale structure, a complex system of filaments, sheets, and spherical knots at the intersections of filaments form. On the mass scales covered by our simulations (5x10^5 - 1x10^9\\Ms) that collapse at redshifts z>25, we find that only at the spherical knots can enough H2 be formed (n_{H_2}/n_H > 5x10^-4) to cool the gas appreciably. Quantities such as the time dependence of the formation of H2 molecules, the final H2 fraction, and central densities from the simulations are compared to the theoretical predictions of Abel (1995) and Tegmark et al. (1997) and found to agree remarkably well. Comparing the 3-D results to an isobaric collapse model we further discuss the possible implications of the extensive merging of small structure that is inherent in hierarchical models. Typically only 5-8% percent of the total baryonic mass in the collapsing structures is found to cool significanlty. Assuming the Padoan (1995) model for star formation our results would predict the first stellar systems to be as small as ~30\\Ms. Some implications for primordial globular cluster formation scenarios are also discussed.

  8. Formation of hypernuclei in high energy reactions within a covariant transport model

    E-Print Network [OSTI]

    T. Gaitanos; H. Lenske; U. Mosel

    2009-04-14

    We investigate the formation of fragments with strangeness degrees of freedom in proton- and heavy-ion-induced reactions at high relativistic energies. The model used is a combination of a dynamical transport model and a statistical approach of fragment formation. We discuss in detail the applicability and limitations of such a hybrid model by comparing data on spectator fragmentation at relativistic $SIS/GSI$-energies. The theoretical results are analyzed in terms of spectator fragmentation with strangeness degrees of freedom such as the production of single-$\\Lambda-{}^{3,4,5}He$ hypernuclei. We provide theoretical estimates on the spectra and on inclusive cross sections of light hypernuclei, which could be helpful for future experiments on hypernuclear physics at the new GSI- and J-PARC-facilities.

  9. Singular front formation in a model for quasigeostrophic flow Peter Constantin

    E-Print Network [OSTI]

    Tabak, Esteban G.

    Singular front formation in a model for quasigeostrophic flow Peter Constantin Department of Mathematics, University of Chicago, Chicago, Illinois 60637 Andrew J. Majda Department of Mathematics, whether it predicts the formation of sharp fronts associated with boundaries between air masses

  10. Nonlinear structure formation in the cubic Galileon gravity model

    SciTech Connect (OSTI)

    Barreira, Alexandre; Li, Baojiu; Hellwing, Wojciech A.; Baugh, Carlton M.; Pascoli, Silvia E-mail: baojiu.li@durham.ac.uk E-mail: c.m.baugh@durham.ac.uk

    2013-10-01

    We model the linear and nonlinear growth of large scale structure in the Cubic Galileon gravity model, by running a suite of N-body cosmological simulations using the ECOSMOG code. Our simulations include the Vainshtein screening effect, which reconciles the Cubic Galileon model with local tests of gravity. In the linear regime, the amplitude of the matter power spectrum increases by ? 20% with respect to the standard ?CDM model today. The modified expansion rate accounts for ? 15% of this enhancement, while the fifth force is responsible for only ? 5%. This is because the effective unscreened gravitational strength deviates from standard gravity only at late times, even though it can be twice as large today. In the nonlinear regime (k?>0.1h Mpc{sup ?1}), the fifth force leads to only a modest increase (?<8%) in the clustering power on all scales due to the very efficient operation of the Vainshtein mechanism. Such a strong effect is typically not seen in other models with the same screening mechanism. The screening also results in the fifth force increasing the number density of halos by less than 10%, on all mass scales. Our results show that the screening does not ruin the validity of linear theory on large scales which anticipates very strong constraints from galaxy clustering data. We also show that, whilst the model gives an excellent match to CMB data on small angular scales (l?>50), the predicted integrated Sachs-Wolfe effect is in tension with Planck/WMAP results.

  11. Chemical Enrichment in Damped Lyman Alpha Systems From Hierarchical Galaxy Formation Models

    E-Print Network [OSTI]

    Katsuya Okoshi; Masahiro Nagashima; Naoteru Gouda; Satoshi Yoshioka

    2003-11-25

    We investigate chemical enrichment in Damped Lyman alpha (DLA) systems in the hierarchical structure formation scenario using a semi-analytic model of galaxy formation. The model developed by Nagashima, Totani, Gouda and Yoshii takes into account various selection effects on high-redshift galaxies and can show fundamental observational properties of galaxies, such as luminosity functions and number-magnitude/redshift relations. DLA systems offer the possibilities of measuring metal abundance more accurately than faint galaxies. For example, recent measurements of zinc abundance can provide good evidence for understanding the processes of metal pollution and star formation in DLA systems because zinc is virtually unaffected by dust depletion. Here we focus on this advantage for observation in order to explore the metallicity evolution in DLA systems at high redshifts. We can consistently show the metallicity evolution for reasonable models which also reproduce fundamental properties of local galaxy population. This result suggests that the chemical evolution of DLA systems can be consistently reconciled with the observational features of typical galaxies. We also investigate other properties of DLA systems (column density distribution and mass density of cold gas), and find that star formation in massive galaxies should be more active than that in low-mass ones. This is consistent with the results by Nagashima et al. and Cole et al. in which the star formation timescale is set by reproducing cold gas mass fraction in local spiral galaxies. Finally we discuss host galaxies associated with DLA systems. We conclude that they primarily consist of sub-L* and/or dwarf galaxies from the observations.

  12. Modeling the Influence of Interaction Layer Formation on Thermal Conductivity of U–Mo Dispersion Fuel

    SciTech Connect (OSTI)

    Burkes, Douglas; Casella, Andrew M.; Huber, Tanja K.

    2015-01-01

    The Global Threat Reduction Initiative Program continues to develop existing and new plate- and rod-type research and test reactor fuels with maximum attainable uranium loadings capable of potentially converting a number of the world’s remaining high-enriched uranium fueled reactors to low-enriched uranium fuel. Currently, the program is focused on assisting with the development and qualification of an even higher density fuel type consisting of a uranium-molybdenum (U-Mo) alloy dispersed in an aluminum matrix. Thermal conductivity is an important consideration in determining the operational temperature of the fuel plate and can be influenced by interaction layer formation between the fuel and matrix, porosity that forms during fabrication of the fuel plates, and upon the concentration of the dispersed phase within the matrix. This paper develops and validates a simple model to study the influence of interaction layer formation and conductivity, fuel particle size, and volume fraction of fuel dispersed in the matrix on the effective conductivity of the composite. The model shows excellent agreement with results previously presented in the literature. In particular, the thermal conductivity of the interaction layer does not appear to be important in determining the overall conductivity of the composite, while formation of the interaction layer and subsequent consumption of the matrix reveals a rather significant effect. The effective thermal conductivity of the composite can be influenced by the fuel particle distribution by minimizing interaction layer formation and preserving the higher thermal conductivity matrix.

  13. Reuse of Verification Results Conditional Model Checking, Precision Reuse,

    E-Print Network [OSTI]

    Beyer, Dirk

    further verification runs of the system; information about the level of abstraction in the abstract modelReuse of Verification Results Conditional Model Checking, Precision Reuse, and Verification checker which parts of the system should be verified; thus, later verification runs can use the output

  14. Galaxy Formation & Dark Matter Modelling in the Era of the Square Kilometre Array

    E-Print Network [OSTI]

    Power, C; Qin, B; Baugh, C M; Cunnama, D; Fu, J; Kim, H S; Lacey, C G; Li, L; Obreschkow, D; Wang, J; Wang, Y; Zhu, M

    2015-01-01

    Theoretical galaxy formation models are an established and powerful tool for interpreting the astrophysical significance of observational data, particularly galaxy surveys. Such models have been utilised with great success by optical surveys such as 2dFGRS and SDSS, but their application to radio surveys of cold gas in galaxies has been limited. In this chapter we describe recent developments in the modelling of the cold gas properties in the models, and how these developments are essential if they are to be applied to cold gas surveys of the kind that will be carried out with the SKA. By linking explicitly a galaxy's star formation rate to the abundance of molecular hydrogen in the galaxy rather than cold gas abundance, as was assumed previously, the latest models reproduce naturally many of the global atomic and molecular hydrogen properties of observed galaxies. We review some of the key results of the latest models and highlight areas where further developments are necessary. We discuss also how model pre...

  15. Modeling of Nonuniform Degradation in Large-Format Li-ion Batteries (Presentation)

    SciTech Connect (OSTI)

    Smith, K.; Kim, G. H.; Pesaran, A.

    2009-05-01

    Study of impacts of large-format cell design features on battery useful life to improve battery engineering models, including both realistic geometry and physics.

  16. Global models of planetary system formation in radiatively-inefficient protoplanetary discs

    E-Print Network [OSTI]

    Hellary, Phil

    2011-01-01

    (Abridged) We present the results of N-body simulations of planetary systems formation in radiatively-inefficient disc models, where positive corotation torques may counter the rapid inward migration of low mass planets driven by Lindblad torques. The aim of this work is to examine the nature of planetary systems that arise from oligarchic growth in such discs. We adapt the commonly-used Mercury-6 symplectic integrator by including simple prescriptions for planetary migration (types I and II), planetary atmospheres that enhance the probability of planetesimal accretion by protoplanets, gas accretion onto forming planetary cores, and gas disc dispersal. We perform a suite of simulations for a variety of disc models with power-law surface density and tempera- ture profiles, with a focus on models in which unsaturated corotation torques can drive outward migration of protoplanets. In some models we account for the quenching of corotation torques that arises when planetary orbits become eccentric. Approximately h...

  17. Summary of FY15 results of benchmark modeling activities

    SciTech Connect (OSTI)

    Arguello, J. Guadalupe

    2015-08-01

    Sandia is participating in the third phase of an is a contributing partner to a U.S.-German "Joint Project" entitled "Comparison of current constitutive models and simulation procedures on the basis of model calculations of the thermo-mechanical behavior and healing of rock salt." The first goal of the project is to check the ability of numerical modeling tools to correctly describe the relevant deformation phenomena in rock salt under various influences. Achieving this goal will lead to increased confidence in the results of numerical simulations related to the secure storage of radioactive wastes in rock salt, thereby enhancing the acceptance of the results. These results may ultimately be used to make various assertions regarding both the stability analysis of an underground repository in salt, during the operating phase, and the long-term integrity of the geological barrier against the release of harmful substances into the biosphere, in the post-operating phase.

  18. Inside-Out Infall Formation of Disk Galaxies: Do Predictions Differ from Models without Size Evolution?

    E-Print Network [OSTI]

    Rychard J. Bouwens; Laura Cayon; Joseph Silk

    1997-09-13

    We develop an idealized inside-out formation model for disk galaxies to include a realistic mix of galaxy types and luminosities that provides a fair match to the traditional observables. The predictions of our infall models are compared against identical models with no-size evolution by generating fully realistic simulations of the HDF, from which we recover the angular size distributions. We find that our infall models produce nearly identical angular size distributions to those of our no-size evolution models in the case of a Omega = 0 geometry but produce slightly smaller sizes in the case of a Omega = 1 geometry, a difference we associate with the fact that there is a different amount of cosmic time in our two models for evolving to relatively low redshifts (z \\approx 1-2). Our infall models also predict a slightly smaller (11% - 29%) number of large (disk scale lengths > 4 h_{50} ^{-1} kpc) galaxies at z \\approx 0.7 for the CFRS as well as different increases in the central surface brightness of the disks for early-type spirals, the infall model predicting an increase by 1.2 magnitudes out to z \\approx 2 (Omega = 0), 1 (Omega = 1), while our no-size evolution models predict an increase of only 0.5 magnitude. This result suggests that infall models could be important for explaining the 1.2-1.6 magnitude increase in surface brightness reported by Schade et al. (1995, 1996a, 1996b).

  19. Modeling Results For the ITER Cryogenic Fore Pump. Final Report

    SciTech Connect (OSTI)

    Pfotenhauer, John M.; Zhang, Dongsheng

    2014-03-31

    A numerical model characterizing the operation of a cryogenic fore-pump (CFP) for ITER has been developed at the University of Wisconsin – Madison during the period from March 15, 2011 through June 30, 2014. The purpose of the ITER-CFP is to separate hydrogen isotopes from helium gas, both making up the exhaust components from the ITER reactor. The model explicitly determines the amount of hydrogen that is captured by the supercritical-helium-cooled pump as a function of the inlet temperature of the supercritical helium, its flow rate, and the inlet conditions of the hydrogen gas flow. Furthermore the model computes the location and amount of hydrogen captured in the pump as a function of time. Throughout the model’s development, and as a calibration check for its results, it has been extensively compared with the measurements of a CFP prototype tested at Oak Ridge National Lab. The results of the model demonstrate that the quantity of captured hydrogen is very sensitive to the inlet temperature of the helium coolant on the outside of the cryopump. Furthermore, the model can be utilized to refine those tests, and suggests methods that could be incorporated in the testing to enhance the usefulness of the measured data.

  20. NEPHELINE FORMATION STUDY FOR SLUDGE BATCH 4: PHASE 3 EXPERIMENTAL RESULTS

    SciTech Connect (OSTI)

    Fox, K

    2006-05-01

    This Phase 3 study was undertaken to complement the previous phases of the nepheline formation studies1, 2 by continuing the investigation into the ability of the nepheline discriminator to predict the occurrence of nepheline crystallization in Sludge Batch 4 (SB4) glasses and into the impact of such phases on the durability of the SB4 glasses. The Phase 3 study had two primary objectives. The first was to continue to demonstrate the ability of the discriminator value to adequately predict the nepheline formation potential for specific glass systems of interest. The second was to generate additional data that have a high probability of supporting the SB4 variability study. To support these two objectives, sixteen glasses were selected based on the most recent SB4 compositional projection, Case 15C Blend 1.3 Four different frits were included, based on previous assessments of projected operating windows and melt rate,4, 5 with four WLs selected for each frit. Eight of these frit-sludge combinations covered WLs which tightly bound the nepheline discriminator value of 0.62, with the intent of refining this value to a level of confidence where it can be incorporated into offline administrative controls and/or the Process Composition Control System (PCCS) to support Slurry Mix Evaporator (SME) acceptability decisions. The remaining eight frit-sludge combinations targeted lower WLs (35 and 40%) and were prepared and analyzed to contribute needed data to the ComPro database6 to support a potential variability study for SB4.

  1. A PKN Hydraulic Fracture Model Study and Formation Permeability Determination 

    E-Print Network [OSTI]

    Xiang, Jing

    2012-02-14

    Hydraulic fracturing is an important method used to enhance the recovery of oil and gas from reservoirs, especially for low permeability formations. The distribution of pressure in fractures and fracture geometry are needed to design conventional...

  2. TSUNAMI BENCHMARK RESULTS FOR FULLY NONLINEAR BOUSSINESQ WAVE MODEL

    E-Print Network [OSTI]

    Kirby, James T.

    TSUNAMI BENCHMARK RESULTS FOR FULLY NONLINEAR BOUSSINESQ WAVE MODEL FUNWAVE-TVD, VERSION 1 by the National Tsunami Hazard Mitigation Program CENTER FOR APPLIED COASTAL RESEARCH Ocean Engineering Laboratory University of Delaware Newark, Delaware 19716 #12;Abstract This report describes tsunami benchmark testing

  3. FORMATION OF DEPTH HOAR RESULTING FROM THERMAL OPTIMIZATION OF SNOW MICROSTRUCTURE

    E-Print Network [OSTI]

    necessary to induce the corresponding flow is a measure of the system efficiency. Kinetic metamorphism to increase the heat transport efficiency. The optimal geometric configuration is a system of well thermal energy through the ice, the system became more efficient. This progression resulted from

  4. Modeling of NOx formation in circular laminar jet flames 

    E-Print Network [OSTI]

    Siwatch, Vivek

    2007-04-25

    of air entrainment by jet depends upon the Sc number of fuel. The higher the Sc number, the higher is the air entrained which lowers the flame temperature and hence NOx formation. With increasing Sc number, flame volume increases which leads...

  5. Modeling of magnetic island formation in magnetic reconnection experiment

    E-Print Network [OSTI]

    Ji, Hantao

    the spontaneous FRC formation with effective plasma heating by magnetic reconnection.6 In the Magnetic, Gifu, 509-5292, Japan M. Yamada and H. Ji Plasma Physics Laboratory, Princeton University, Princeton found in the Magnetic Reconnection Experiment MRX M. Yamada, H. Ji, S. Hsu, et al., Phys. Plasmas 4

  6. Formation of S0 galaxies through mergers. V. Antitruncated stellar discs resulting from major mergers

    E-Print Network [OSTI]

    Borlaff, Alejandro; Rodríguez-Pérez, Cristina; Querejeta, Miguel; Tapia, Trinidad; Pérez-González, Pablo G; Zamorano, Jaime; Gallego, Jesús; Beckman, John

    2014-01-01

    Lenticular galaxies (S0s) are more likely to host antitruncated (Type-III) stellar discs than galaxies of later Hubble types. Major mergers are popularly considered too violent mechanisms to form these breaks. We have investigated whether major mergers can result into S0-like remnants with realistic antitruncated stellar discs or not. We have analysed 67 relaxed S0 and E/S0 remnants resulting from dissipative N-body simulations of major mergers from the GalMer database. We have simulated realistic R-band surface brightness profiles of the remnants to identify those with antitruncated stellar discs. Their inner and outer discs and the breaks are quantitatively characterized to compare with real data. Nearly 70% of our S0-like remnants are antitruncated, meaning that major mergers that result in S0s have a high probability of producing Type-III stellar discs. Our remnants lie on top of the extrapolations of the observational trends (towards brighter magnitudes and higher break radii) in several photometric diag...

  7. An Empirical Model for the Galaxy Luminosity and Star-Formation Rate Function at High Redshift

    E-Print Network [OSTI]

    Mashian, Natalie; Loeb, Abraham

    2015-01-01

    Using the most recent measurements of the ultraviolet (UV) luminosity functions (LFs) and dust estimates of early galaxies, we derive updated dust-corrected star-formation rate functions (SFRFs) at z~4-8, which we model to predict the evolution to higher redshifts, z>8. We employ abundance matching techniques to calibrate a relation between galaxy star formation rate (SFR) and host halo mass M{_h} by mapping the shape of the observed SFRFs at z~4-8 to that of the halo mass function. The resulting scaling law remains roughly constant over this redshift range. We apply the average SFR-M{_h} relation to reproduce the observed SFR functions at 4 10 indicate that JWST will be able to detect galaxies out to z~15 with an extensive treasury sized program. We also derive the redshift evolution of the star formation rate density and associated reionization history by galaxies for which we find that the inclusion of galaxies with SFRs well below the current detection limit leads to a fully reionized universe by z~6.5 an...

  8. Model of coarsening and vortex formation in vibrated granular rods Igor S. Aranson

    E-Print Network [OSTI]

    Tsimring, Lev S.

    Model of coarsening and vortex formation in vibrated granular rods Igor S. Aranson Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 Lev S. Tsimring Institute for Nonlinear Science spontaneous formation of the long-range orientational order and large- scale vortices in a system of vibrated

  9. Modeling Coupled Processes in Clay Formations for Radioactive Waste Disposal

    E-Print Network [OSTI]

    Liu, Hui-Hai

    2010-01-01

    International Workshop on Geomechanics, hydromechanical andflow, heat transport and geomechanics, by linking the twotransport modeling and geomechanics using the reactive

  10. Modeling Coupled Processes in Clay Formations for Radioactive Waste Disposal

    E-Print Network [OSTI]

    Liu, Hui-Hai

    2010-01-01

    and the future path of diagenesis have important effects onthe basic basin model for diagenesis. Therefore, some method

  11. A Theoretical Model of Pattern Formation in Coral Reefs

    E-Print Network [OSTI]

    the behavior of perturba- tions in an initially uniform model system. Alan Turing was one of the first

  12. Modeling Coupled Processes in Clay Formations for Radioactive Waste Disposal

    E-Print Network [OSTI]

    Liu, Hui-Hai

    2010-01-01

    Transport Modelling in the Paris Basin over Geologic Time,hydrologic phenomena in the Paris Basin (Jost et al. 2005)

  13. Experimental and artificial neural network modeling study on soot formation in premixed hydrocarbon flamesq

    E-Print Network [OSTI]

    Senkan, Selim M.

    Experimental and artificial neural network modeling study on soot formation in premixed hydrocarbon classical light scattering measurement techniques. The experimental data revealed that the soot properties rights reserved. Keywords: Soot; Hydrocarbon flames; Artificial neural networks 1. Introduction

  14. Recent results and persisting problems in modeling flow induced coalescence

    SciTech Connect (OSTI)

    Fortelný, I. E-mail: juza@imc.cas.cz; Jza, J. E-mail: juza@imc.cas.cz

    2014-05-15

    The contribution summarizes recent results of description of the flow induced coalescence in immiscible polymer blends and addresses problems that call for which solving. The theory of coalescence based on the switch between equations for matrix drainage between spherical or deformed droplets provides a good agreement with more complicated modeling and available experimental data for probability, P{sub c}, that the collision of droplets will be followed by their fusion. A new equation for description of the matrix drainage between deformed droplets, applicable to the whole range of viscosity ratios, p, of the droplets and matrixes, is proposed. The theory facilitates to consider the effect of the matrix elasticity on coalescence. P{sub c} decreases with the matrix relaxation time but this decrease is not pronounced for relaxation times typical of most commercial polymers. Modeling of the flow induced coalescence in concentrated systems is needed for prediction of the dependence of coalescence rate on volume fraction of droplets. The effect of the droplet anisometry on P{sub c} should be studied for better understanding the coalescence in flow field with high and moderate deformation rates. A reliable description of coalescence in mixing and processing devices requires proper modeling of complex flow fields.

  15. Preliminary time-phased TWRS process model results

    SciTech Connect (OSTI)

    Orme, R.M.

    1995-03-24

    This report documents the first phase of efforts to model the retrieval and processing of Hanford tank waste within the constraints of an assumed tank farm configuration. This time-phased approach simulates a first try at a retrieval sequence, the batching of waste through retrieval facilities, the batching of retrieved waste through enhanced sludge washing, the batching of liquids through pretreatment and low-level waste (LLW) vitrification, and the batching of pretreated solids through high-level waste (HLW) vitrification. The results reflect the outcome of an assumed retrieval sequence that has not been tailored with respect to accepted measures of performance. The batch data, composition variability, and final waste volume projects in this report should be regarded as tentative. Nevertheless, the results provide interesting insights into time-phased processing of the tank waste. Inspection of the composition variability, for example, suggests modifications to the retrieval sequence that will further improve the uniformity of feed to the vitrification facilities. This model will be a valuable tool for evaluating suggested retrieval sequences and establishing a time-phased processing baseline. An official recommendation on tank retrieval sequence will be made in September, 1995.

  16. Dark Stars: Improved Models and First Pulsation Results

    E-Print Network [OSTI]

    Tanja Rindler-Daller; Michael H. Montgomery; Katherine Freese; Donald E. Winget; Bill Paxton

    2015-01-12

    We use the stellar evolution code MESA to study dark stars. Dark stars (DSs), which are powered by dark matter (DM) self-annihilation rather than by nuclear fusion, may be the first stars to form in the Universe. We compute stellar models for accreting DSs with masses up to 10^6 M_{sun}. The heating due to DM annihilation is self-consistently included, assuming extended adiabatic contraction of DM within the minihalos in which DSs form. We find remarkably good overall agreement with previous models, which assumed polytropic interiors. There are some differences in the details, with positive implications for observability. We found that, in the mass range of 10^4 -10^5 M_{sun}, our DSs are hotter by a factor of 1.5 than those in Freese et al.(2010), are smaller in radius by a factor of 0.6, denser by a factor of 3 - 4, and more luminous by a factor of 2. Our models also confirm previous results, according to which supermassive DSs are very well approximated by (n=3)-polytropes. We also perform a first study of dark star pulsations. Our DS models have pulsation modes with timescales ranging from less than a day to more than two years in their rest frames, at z ~ 15, depending on DM particle mass and overtone number. Such pulsations may someday be used to identify bright, cool objects uniquely as DSs; if properly calibrated, they might, in principle, also supply novel standard candles for cosmological studies.

  17. Structure formation in a nonlocally modified gravity model

    SciTech Connect (OSTI)

    Park, Sohyun; Dodelson, Scott

    2013-01-01

    We study a nonlocally modified gravity model proposed by Deser and Woodard which gives an explanation for current cosmic acceleration. By deriving and solving the equations governing the evolution of the structure in the Universe, we show that this model predicts a pattern of growth that differs from standard general relativity (+dark energy) at the 10-30% level. These differences will be easily probed by the next generation of galaxy surveys, so the model should be tested shortly.

  18. MODELING RESULTS FROM CESIUM ION EXCHANGE PROCESSING WITH SPHERICAL RESINS

    SciTech Connect (OSTI)

    Nash, C.; Hang, T.; Aleman, S.

    2011-01-03

    Ion exchange modeling was conducted at the Savannah River National Laboratory to compare the performance of two organic resins in support of Small Column Ion Exchange (SCIX). In-tank ion exchange (IX) columns are being considered for cesium removal at Hanford and the Savannah River Site (SRS). The spherical forms of resorcinol formaldehyde ion exchange resin (sRF) as well as a hypothetical spherical SuperLig{reg_sign} 644 (SL644) are evaluated for decontamination of dissolved saltcake wastes (supernates). Both SuperLig{reg_sign} and resorcinol formaldehyde resin beds can exhibit hydraulic problems in their granular (nonspherical) forms. SRS waste is generally lower in potassium and organic components than Hanford waste. Using VERSE-LC Version 7.8 along with the cesium Freundlich/Langmuir isotherms to simulate the waste decontamination in ion exchange columns, spherical SL644 was found to reduce column cycling by 50% for high-potassium supernates, but sRF performed equally well for the lowest-potassium feeds. Reduced cycling results in reduction of nitric acid (resin elution) and sodium addition (resin regeneration), therefore, significantly reducing life-cycle operational costs. These findings motivate the development of a spherical form of SL644. This work demonstrates the versatility of the ion exchange modeling to study the effects of resin characteristics on processing cycles, rates, and cold chemical consumption. The value of a resin with increased selectivity for cesium over potassium can be assessed for further development.

  19. Two-dimensional modeling of the cathode sheath formation during the streamer-cathode interaction

    SciTech Connect (OSTI)

    Yan, Wen; Sang, Chaofeng; Wang, Dezhen, E-mail: wangdez@dlut.edu.cn [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)] [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); Liu, Fucheng [College of Physics Science and Technology, Hebei University, Baoding 071002 (China)] [College of Physics Science and Technology, Hebei University, Baoding 071002 (China)

    2014-01-15

    In this paper, a computational simulation of the sheath formation during the streamer-surface interaction at atmospheric pressure is presented. A two-dimensional fluid model of a point-to-plane configuration is applied to investigate the evolution of the discharge in the vicinity of cathode plane. The effects of the surfaces on the properties of streamer have been studied for three cases, i.e., conductive surface with secondary electron emission (SEE), conductive surface without SEE, and dielectric surface. In all cases, we found that the axial propagation velocity of the streamer front decreases as the streamer arrives at the boundary of the cathode sheath. And the simulation results showed that the properties of the surface have a significant effect on the streamer. Besides the influences, the secondary emission coefficient and the relative permittivity on the streamer-surface interactions are also studied.

  20. The Modified Weighted Slab Technique: Models and Results

    E-Print Network [OSTI]

    Frank C. Jones; Andrew Lukasiak; Vladimir Ptuskin; William Webber

    2000-07-19

    In an attempt to understand the source and propagation of galactic cosmic rays we have employed the Modified Weighted Slab technique along with recent values of the relevant cross sections to compute primary to secondary ratios including B/C and Sub-Fe/Fe for different galactic propagation models. The models that we have considered are the disk-halo diffusion model, the dynamical halo wind model, the turbulent diffusion model and a model with minimal reacceleration. The modified weighted slab technique will be briefly discussed and a more detailed description of the models will be given. We will also discuss the impact that the various models have on the problem of anisotropy at high energy and discuss what properties of a particular model bear on this issue.

  1. Unsteady Flamelet Modeling of Soot Formation in Turbulent Diffusion Flames

    E-Print Network [OSTI]

    Pitsch, Heinz

    and molecular oxygen. In practical devices of technical relevance, such as Diesel engines and gas turbines, soot of Applied Mechanics and Engineering Science Center for Energy and Combustion Research, University and Reactive Systems Combustion, Science, and Technology, 158, pp. 389-406, 2000 #12;Unsteady Flamelet Modeling

  2. Formation of algae growth constitutive relations for improved algae modeling.

    SciTech Connect (OSTI)

    Gharagozloo, Patricia E.; Drewry, Jessica L.

    2013-01-01

    This SAND report summarizes research conducted as a part of a two year Laboratory Directed Research and Development (LDRD) project to improve our abilities to model algal cultivation. Algae-based biofuels have generated much excitement due to their potentially large oil yield from relatively small land use and without interfering with the food or water supply. Algae mitigate atmospheric CO2 through metabolism. Efficient production of algal biofuels could reduce dependence on foreign oil by providing a domestic renewable energy source. Important factors controlling algal productivity include temperature, nutrient concentrations, salinity, pH, and the light-to-biomass conversion rate. Computational models allow for inexpensive predictions of algae growth kinetics in these non-ideal conditions for various bioreactor sizes and geometries without the need for multiple expensive measurement setups. However, these models need to be calibrated for each algal strain. In this work, we conduct a parametric study of key marine algae strains and apply the findings to a computational model.

  3. Fast Track Reservoir Modeling of Shale Formations in the Appalachian Basin.

    E-Print Network [OSTI]

    Mohaghegh, Shahab

    July 2010 SPE 139101 Fast Track Reservoir Modeling of Shale Formations in the Appalachian Basin. Application to Lower Huron Shale in Eastern Kentucky O. Grujic, S.D. Mohaghegh, G. Bromhal The research Huron Shale · Data Preparation · Conventional Reservoir Simulation vs. Top Down Reservoir Modeling · Top

  4. A Direct Reputation Model for VO Formation Arturo Avila-Rosas1

    E-Print Network [OSTI]

    Luck, Michael

    A Direct Reputation Model for VO Formation Arturo Avila-Rosas1 and Michael Luck2 1 Instituto. Agents can use their experiences gained in direct past interactions to model other's reputation and decid capabilities and limited resources at their disposal, that come together to share skills or core competences

  5. Comprehensive Electricity Competition Act: A Comparison of Model Results, The

    Reports and Publications (EIA)

    1999-01-01

    This report describes the Energy Information Administration's use of the National Energy Modeling System (NEMS) to evaluate the effects of the Administration's restructuring proposal using the parameter settings and assumptions from the Policy Office Electricity Modeling System (POEMS) analysis.

  6. Overmerging and M/L ratios in phenomenological galaxy formation models

    E-Print Network [OSTI]

    Eelco van Kampen; Raul Jimenez; John A. Peacock

    1999-04-21

    We show that the discrepancy between the Tully-Fisher relation and the luminosity function predicted by most phenomenological galaxy formation models is mainly due to overmerging of galaxy haloes. We have circumvented this overmerging problem, which is inherent in both the Press-Schechter formalism and dissipationless N-body simulations, by including a specific galaxy halo formation recipe into an otherwise standard N-body code. This numerical technique provides the merger trees which, together with simplified gas dynamics and star formation physics, constitute our implementation of a phenomenological galaxy formation model. Resolving the overmerging problem provides us with the means to match both the I-band Tully-Fisher relation and the B and K band luminosity functions within an EdS sCDM structure formation scenario. It also allows us to include models for chemical evolution and starbursts, which improves the match to observational data and renders the modelling more realistic. We show that the inclusion of chemical evolution into the modelling requires a significant fraction of stars to be formed in short bursts triggered by merging events.

  7. Modeling of Reoxidation Inclusion Formation During Filling of Steel Castings

    E-Print Network [OSTI]

    Beckermann, Christoph

    larger inclusions entering the mold cavity from the ladle, and they can also be born on the metal free of the resulting defect areas with weld metal. Inclusions that remain in the casting adversely affect machining inclusions, which form when deoxidized steel comes into contact with oxygen during mold filling, make up

  8. Results of the 2013 UT modeling benchmark obtained with models implemented in CIVA

    SciTech Connect (OSTI)

    Toullelan, Gwénaël; Raillon, Raphaële; Chatillon, Sylvain; Lonne, Sébastien

    2014-02-18

    The 2013 Ultrasonic Testing (UT) modeling benchmark concerns direct echoes from side drilled holes (SDH), flat bottom holes (FBH) and corner echoes from backwall breaking artificial notches inspected with a matrix phased array probe. This communication presents the results obtained with the models implemented in the CIVA software: the pencilmodel is used to compute the field radiated by the probe, the Kirchhoff approximation is applied to predict the response of FBH and notches and the SOV (Separation Of Variables) model is used for the SDH responses. The comparison between simulated and experimental results are presented and discussed.

  9. Summary Results for Brine Migration Modeling Performed by LANL...

    Energy Savers [EERE]

    modeling related to coupled processes involving brine and vapor migration in geologic salt, focusing on recent developments and studies conducted at Sandia, Los Alamos, and...

  10. Summary Results for Brine Migration Modeling Performed by LANL...

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

    tightly coupled solutions (Kim, 2010; Prevost, 2014). Tight coupling does not require freezing state variables or iterating between models, but it requires more computer memory and...

  11. Testing Planet Formation Models with Gaia $\\mu$as Astrometry

    E-Print Network [OSTI]

    Sozzetti, A; Lattanzi, M G; Spagna, A; Morbidelli, R; Pannunzio, R; Pourbaix, D; Queloz, D

    2007-01-01

    In this paper, we first summarize the results of a large-scale double-blind tests campaign carried out for the realistic estimation of the Gaia potential in detecting and measuring planetary systems. Then, we put the identified capabilities in context by highlighting the unique contribution that the Gaia exoplanet discoveries will be able to bring to the science of extrasolar planets during the next decade.

  12. Testing Planet Formation Models with Gaia $?$as Astrometry

    E-Print Network [OSTI]

    A. Sozzetti; S. Casertano; M. G. Lattanzi; A. Spagna; R. Morbidelli; R. Pannunzio; D. Pourbaix; D. Queloz

    2007-11-30

    In this paper, we first summarize the results of a large-scale double-blind tests campaign carried out for the realistic estimation of the Gaia potential in detecting and measuring planetary systems. Then, we put the identified capabilities in context by highlighting the unique contribution that the Gaia exoplanet discoveries will be able to bring to the science of extrasolar planets during the next decade.

  13. Type Ia supernovae in a hierarchical galaxy formation model: the Milky Way

    E-Print Network [OSTI]

    Masahiro Nagashima; Takashi Okamoto

    2006-02-03

    We investigate chemical evolution in Milky Way-like galaxies based on the cold dark matter model in which cosmic structures form via hierarchical merging. We introduce chemical enrichment due to type Ia supernovae (SNe Ia) into the Mitaka semi-analytic galaxy formation model developed by Nagashima & Yoshii. For the first time we derive distributions of stellar metallicities and their ratios in Milky Way-like galaxies treating chemical enrichment due to SNe Ia in a hierarchical galaxy formation model self-consistently. As a first attempt, we assume all SNe Ia to have the same lifetime, and assume instantaneous recycling for type II supernovae (SNe II). We find that our model reproduces well the metal abundance ratio [O/Fe] against [Fe/H] and the {iron metallicity distribution function} in the solar neighborhood. This means that the so-called G-dwarf problem is resolved by the hierarchical formation of galaxies, and a gas infall term introduced in traditional monolithic collapse models to solve this problem is well explained by the mixture of some physical processes such as hierarchical merging of dark halos, gas cooling, energy feedback and injection of gas and metals into hot gas due to supernovae. Our model predicts more oxygen-enhanced stars in bulges at [Fe/H] $\\simeq 0$ than in disks. This trend seems to be supported by recent observations while they have still uncertainties. More data in number and accuracy will provide independent and important constraints on galaxy formation. (abridged)

  14. Review of the dWind Model Conceptual Results

    SciTech Connect (OSTI)

    Baring-Gould, Ian; Gleason, Michael; Preus, Robert; Sigrin, Ben

    2015-09-16

    This presentation provides an overview of the dWind model, including its purpose, background, and current status. Baring-Gould presented this material as part of the September 2015 WINDExchange webinar.

  15. Stringy models of modified gravity: space-time defects and structure formation

    SciTech Connect (OSTI)

    Mavromatos, Nick E.; Sakellariadou, Mairi; Yusaf, Muhammad Furqaan, E-mail: nikolaos.mavromatos@kcl.ac.uk, E-mail: mairi.sakellariadou@kcl.ac.uk, E-mail: muhammad.yusaf@kcl.ac.uk [King's College London, Department of Physics, Strand, London WC2R 2LS (United Kingdom)

    2013-03-01

    Starting from microscopic models of space-time foam, based on brane universes propagating in bulk space-times populated by D0-brane defects (''D-particles''), we arrive at effective actions used by a low-energy observer on the brane world to describe his/her observations of the Universe. These actions include, apart from the metric tensor field, also scalar (dilaton) and vector fields, the latter describing the interactions of low-energy matter on the brane world with the recoiling point-like space-time defect (D-particle). The vector field is proportional to the recoil velocity of the D-particle and as such it satisfies a certain constraint. The vector breaks locally Lorentz invariance, which however is assumed to be conserved on average in a space-time foam situation, involving the interaction of matter with populations of D-particle defects. In this paper we clarify the role of fluctuations of the vector field on structure formation and galactic growth. In particular we demonstrate that, already at the end of the radiation era, the (constrained) vector field associated with the recoil of the defects provides the seeds for a growing mode in the evolution of the Universe. Such a growing mode survives during the matter dominated era, provided the variance of the D-particle recoil velocities on the brane is larger than a critical value. We note that in this model, as a result of specific properties of D-brane dynamics in the bulk, there is no issue of overclosing the brane Universe for large defect densities. Thus, in these models, the presence of defects may be associated with large-structure formation. Although our string inspired models do have (conventional, from a particle physics point of view) dark matter components, nevertheless it is interesting that the role of ''extra'' dark matter is also provided by the population of massive defects. This is consistent with the weakly interacting character of the D-particle defects, which predominantly interact only gravitationally.

  16. Top-Down Modeling; Practical, Fast-Track, Reservoir Modeling for Shale Formations AAPG/SEG/SPE/SPWLA Hedberg Conference, Austin, TX December 2010

    E-Print Network [OSTI]

    Mohaghegh, Shahab

    1 Top-Down Modeling; Practical, Fast-Track, Reservoir Modeling for Shale Formations AAPG OF SHALE RESOURCE PLAYS" DECEMBER 5-10, 2010 ­ AUSTIN, TEXAS Top-Down Modeling; Practical, Fast Track, Reservoir Simulation & Modeling for Shale Formations Shahab D. Mohaghegh, West Virginia University

  17. PHEV Parcel Delivery Truck Model - Development and Preliminary Results (Presentation)

    SciTech Connect (OSTI)

    Barnitt, R

    2009-10-28

    Describes results of a study to determine the impact of drive cycles on the energy- and cost-effectiveness of plug-in hybrid electric delivery vans.

  18. A generalized kinetic model for the formation and growth of single-walled metal oxide nanotubes

    E-Print Network [OSTI]

    Nair, Sankar

    A generalized kinetic model for the formation and growth of single-walled metal oxide nanotubes G,n a School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA b School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA c

  19. A model of relative position and attitude in a leader-follower spacecraft formation

    E-Print Network [OSTI]

    Gravdahl, Jan Tommy

    Kristiansen, Esten Ingar Grøtli, Per Johan Nicklasson and Jan Tommy Gravdahl Department of Space Technology Narvik University College, Norway Department of Engineering Cybernetics Norwegian University of Science and Technology, Norway Abstract In this paper, a model of a leader-follower spacecraft formation in six degrees

  20. Modeling the Early Stages of Thin Film Formation by Energetic Atom Deposition

    E-Print Network [OSTI]

    Ghoniem, Nasr M.

    .M. GHONIEM The early stages of thin film formation are described by a simple hybrid model that couples a set action of a number of unique atomic processes (sputtering, implantation, nucleation, heating system to condense superthermal free particles on a host material. Ion-beam deposition systems deposit

  1. A simple model for nanofiber formation by rotary jet-spinning Paula Mellado,1,2

    E-Print Network [OSTI]

    Mahadevan, L.

    A simple model for nanofiber formation by rotary jet-spinning Paula Mellado,1,2 Holly A. McIlwee,1 of Engineering and Applied Sciences, Wyss Institute of Biologically Inspired Engineering, Harvard University) Nanofibers are microstructured materials that span a broad range of applications from tissue engineering

  2. Evaluating variable switching and flash methods in modeling carbon sequestration in deep geologic formations

    E-Print Network [OSTI]

    Mills, Richard

    Evaluating variable switching and flash methods in modeling carbon sequestration in deep geologic performance computing to assess the risks involved in carbon sequestration in deep geologic formations-thermal- chemical processes in variably saturated, non-isothermal porous media is applied to sequestration

  3. MECHANICAL TEST RESULTS ON DIPOLE MODEL C-l 25 mm ALUMINUM COLLARS

    E-Print Network [OSTI]

    Peters, C.

    2010-01-01

    RESULTS ON DIPOLE MODEL C-1 25 mm ALUMINUM COLLARS C. PetersRESULTS ON DIPOLE MODEL C-I 25 mm ALUMINUM COLLARS· CraigON DIPOLE MODEL C-I 25 mm ALUMINUM COLLARS Craig Peters

  4. Damped Lyman alpha Absorbing Galaxies At Low Redshifts z<1 From Hierarchical Galaxy Formation Models

    E-Print Network [OSTI]

    Katsuya Okoshi; Masahiro Nagashima

    2004-12-21

    We investigate Damped Ly-alpha absorbing galaxies (DLA galaxies) at low redshifts z<1 in the hierarchical structure formation scenario to clarify the nature of DLA galaxies because observational data of such galaxies mainly at low redshifts are currently available. We find that our model well reproduces distributions of fundamental properties of DLA galaxies such as luminosities, column densities, impact parameters obtained by optical and near-infrared imagings. Our results suggest that DLA systems primarily consist of low luminosity galaxies with small impact parameters (typical radius about 3 kpc, surface brightness from 22 to 27 mag arcsec^{-2}) similar to low surface brightness (LSB) galaxies. In addition, we investigate selection biases arising from the faintness and from the masking effect which prevents us from identifying a DLA galaxy hidden or contaminated by a point spread function of a background quasar. We find that the latter affects the distributions of DLA properties more seriously rather than the former, and that the observational data are well reproduced only when taking into account the masking effect. The missing rate of DLA galaxies by the masking effect attains 60-90 % in the sample at redshift 0formation rates, and find that they are typically about 10^{-2} M_sun yr^{-1} as low as those in LSB galaxies.

  5. Pressure-gain combustion. Part 2: Experimental and model results

    SciTech Connect (OSTI)

    Richards, G.A.; Gemmen, R.S. [Dept. of Energy, Morgantown, WV (United States). Morgantown Energy Technology Center

    1996-07-01

    An experimental investigation of aerovalve pulse combustion is presented. The experimental measurements compare favorably with model predictions from a control-volume analysis of the pulse combustor. Particular emphasis is placed on the mean pressure differences through the combustor as an indicator of the so-called pressure gain performance. Both the operating conditions and combustor geometry are investigated. It is shown that complex fluid/combustion interactions within the combustor make it difficult to isolate the effect of geometric changes. A scaling rule developed from the control-volume analysis is used to produce a combustor geometry capable of producing pressure gain.

  6. H2A Delivery Models and Results | Department of Energy

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

    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 Delicious Rank EERE:FinancingPetroleum12,ExecutiveFinancing Programs | DepartmentINDUSTRIALH-Tank FarmH2DeliveryModels

  7. Unidimensional Models Do Not Fit Unidimensional Mixed Format Data Better than Multidimensional Models

    E-Print Network [OSTI]

    Montgomery, Melinda Sue

    2014-12-31

    This dissertation examines the scaling of large scale assessments containing both dichotomous and polytomous items, mixed format assessments. Because large scale assessments are generally built to measure one construct, ...

  8. High-energy radiation damage in zirconia: Modeling results

    SciTech Connect (OSTI)

    Zarkadoula, E.; Devanathan, R.; Weber, W. J.; Seaton, M. A.; Todorov, I. T.; Nordlund, K.; Dove, M. T.; Trachenko, K.

    2014-02-28

    Zirconia is viewed as a material of exceptional resistance to amorphization by radiation damage, and consequently proposed as a candidate to immobilize nuclear waste and serve as an inert nuclear fuel matrix. Here, we perform molecular dynamics simulations of radiation damage in zirconia in the range of 0.1–0.5?MeV energies with account of electronic energy losses. We find that the lack of amorphizability co-exists with a large number of point defects and their clusters. These, importantly, are largely isolated from each other and therefore represent a dilute damage that does not result in the loss of long-range structural coherence and amorphization. We document the nature of these defects in detail, including their sizes, distribution, and morphology, and discuss practical implications of using zirconia in intense radiation environments.

  9. High-energy radiation damage in zirconia: modeling results

    SciTech Connect (OSTI)

    Zarkadoula, Eva; Devanathan, Ram; Weber, William J.; Seaton, Michael; Todorov, Ilian; Nordlund, Kai; Dove, Martin T.; Trachenko, Kostya

    2014-02-28

    Zirconia has been viewed as a material of exceptional resistance to amorphization by radiation damage, and was consequently proposed as a candidate to immobilize nuclear waste and serve as a nuclear fuel matrix. Here, we perform molecular dynamics simulations of radiation damage in zirconia in the range of 0.1-0.5 MeV energies with the account of electronic energy losses. We find that the lack of amorphizability co-exists with a large number of point defects and their clusters. These, importantly, are largely disjoint from each other and therefore represent a dilute damage that does not result in the loss of long-range structural coherence and amorphization. We document the nature of these defects in detail, including their sizes, distribution and morphology, and discuss practical implications of using zirconia in intense radiation environments.

  10. High-energy radiation damage in zirconia: modeling results

    SciTech Connect (OSTI)

    Zarkadoula, Evangelia; Devanathan, Ram; Weber, William J; Seaton, M; Todorov, I T; Nordlund, Kai; Dove, Martin T; Trachenko, Kostya

    2014-01-01

    Zirconia is viewed as a material of exceptional resistance to amorphization by radiation damage, and consequently proposed as a candidate to immobilize nuclear waste and serve as an inert nuclear fuel matrix. Here, we perform molecular dynamics simulations of radiation damage in zirconia in the range of 0.1-0.5 MeV energies with account of electronic energy losses. We nd that the lack of amorphizability co-exists with a large number of point defects and their clusters. These, importantly, are largely isolated from each other and therefore represent a dilute damage that does not result in the loss of long-range structural coherence and amorphization. We document the nature of these defects in detail, including their sizes, distribution and morphology, and discuss practical implications of using zirconia in intense radiation environments.

  11. Cloud Formation in the Plumes of Solar Chimney Power Generation Facilities: A Modeling Study

    E-Print Network [OSTI]

    Nenes, Athanasios

    the potential impacts on plant capacity resulting from cloud formation within or downwind of the solar chimney. Ideally, renewable energy power plants convert energy from naturally occurring thermal or kinetic sources technology for converting solar energy into electricity that has shown promise in recent years is the so

  12. Numerical Modeling of CO2 Sequestration in Geologic Formations - Recent Results and Open Challenges

    E-Print Network [OSTI]

    Pruess, Karsten

    2006-01-01

    crustal conditions of a geothermal gradient of 30 ?C/km andwater in a normal geothermal gradient of 30 ?C/km with ais held in a normal geothermal gradient of 30 ?C/km and is

  13. Motivation Methods Model configuration Results Forecasting Summary & Outlook Retrieving direct and diffuse radiation with the

    E-Print Network [OSTI]

    Heinemann, Detlev

    Motivation Methods Model configuration Results Forecasting Summary & Outlook 1/ 14 Retrieving. 17, 2015 #12;Motivation Methods Model configuration Results Forecasting Summary & Outlook 2/ 14 Motivation Sky Imager based shortest-term solar irradiance forecasts for local solar energy applications

  14. Vista at CDF: Results of a model-independent search for new physics...

    Office of Scientific and Technical Information (OSTI)

    Vista at CDF: Results of a model-independent search for new physics in 927 pb**-1 at CDF Citation Details In-Document Search Title: Vista at CDF: Results of a model-independent...

  15. Technology and U.S. Emissions Reductions Goals: Results of the EMF 24 Modeling Exercise

    SciTech Connect (OSTI)

    Clarke, Leon E.; Fawcett, Allen; Weyant, John; McFarland, Jim; Chaturvedi, Vaibhav; Zhou, Yuyu

    2014-09-01

    This paper discusses Technology and U.S. Emissions Reductions Goals: Results of the EMF 24 Modeling Exercise

  16. A new chemo-evolutionary population synthesis model for early-type galaxies. II: Observations and Results

    E-Print Network [OSTI]

    A. Vazdekis; R. F. Peletier; J. E. Beckman; E. Casuso

    1997-01-08

    We present here the results of applying a new chemo-evolutionary stellar population model developed by ourselves in a previous paper (Vazdekis et al. 1996) to new high quality observational data of the nuclear regions of two representative elliptical galaxies and the bulge of the Sombrero galaxy. Here we fit in detail about 20 absorption lines and 6 optical and near-infrared colors following two approaches: fitting a single-age single-metallicity model and fitting our full chemical evolutionary model. We find that all of the iron lines are weaker than the best fitting models predict, indicating that the iron-abundance is anomalous and deficient. We also find that the Ca_I index at 4227 A is much lower than predicted by the models. We can obtain good fits for all the other lines and observed colors with models of old and metal-rich stellar populations, and can show that the observed radial gradients are due to metallicity decreasing outward. We find that good fits are obtained both with fully evolutionary models and with single-age single-metallicity models. This is due to the fact that in the evolutionary model more than 80% of stars form with in 1.5 Gyr after the formation of the galaxies. The fact that slightly better fits are obtained with evolutionary models indicates these galaxies contain a small spread in metallicity.

  17. Universitt StuttgartInstitut fr Wasserbau, Lehrstuhl fr Hydromechanik und Hydrosystemmodellierung Workshop on Numerical Models for Carbon Dioxide Storage in Geological Formations

    E-Print Network [OSTI]

    Cirpka, Olaf Arie

    Hydrosystemmodellierung Workshop on Numerical Models for Carbon Dioxide Storage in Geological Formations 1/16 Modelling April 2008 Workshop on Numerical Models for Carbon Dioxide Storage in Geological Formations #12 on Numerical Models for Carbon Dioxide Storage in Geological Formations 2/16 CO2 leakage mitigation using

  18. Chemical evolution in a model for the joint formation of quasars and spheroids

    E-Print Network [OSTI]

    Donatella Romano; Laura Silva; Francesca Matteucci; Luigi Danese

    2002-03-28

    Direct and indirect pieces of observational evidence point to a strong connection between high-redshift quasars and their host galaxies. In the framework of a model where the shining of the quasar is the episode that stops the formation of the galactic spheroid inside a virialized halo, it has been proven possible to explain the submillimetre source counts together with their related statistics and the local luminosity function of spheroidal galaxies. The time delay between the virialization and the quasar manifestation required to fit the counts is short and incresing with decresing the host galaxy mass. In this paper we compute the detailed chemical evolution of gas and stars inside virialized haloes in the framework of the same model, taking into account the combined effects of cooling and stellar feedback. Under the assumption of negligible angular momentum, we are able to reproduce the main observed chemical properties of local ellipticals. In particular, by using the same duration of the bursts which are required in order to fit the submillimetre source counts, we recover the observed increase of the Mg/Fe ratio with galactic mass. Since for the most massive objects the assumed duration of the burst is Tburst < 0.6 Gyr, we end up with a picture for elliptical galaxy formation in which massive spheroids complete their assembly at early times, thus resembling a monolithic collapse, whereas smaller galaxies are allowed for a more prolonged star formation, thus allowing for a more complicated evolutionary history.

  19. 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)

  20. Towards accurate kinetic modeling of prompt NO formation in hydrocarbon flames via the NCN pathway

    SciTech Connect (OSTI)

    Sutton, Jeffrey A. [Department of Mechanical Engineering, The Ohio State University, Columbus, OH 43210 (United States); Fleming, James W. [Navy Technology Center for Safety and Survivability, Chemistry Division, Code 6185, Naval Research Laboratory, Washington, DC 20375-5342 (United States)

    2008-08-15

    A basic kinetic mechanism that can predict the appropriate prompt-NO precursor NCN, as shown by experiment, with relative accuracy while still producing postflame NO results that can be calculated as accurately as or more accurately than through the former HCN pathway is presented for the first time. The basic NCN submechanism should be a starting point for future NCN kinetic and prompt NO formation refinement.

  1. Motivations Problem Formulation Main Results Example Conclusions Robust H Control for Model-Based

    E-Print Network [OSTI]

    Chen, Sheng

    Motivations Problem Formulation Main Results Example Conclusions Robust H Control for Model Formulation Main Results Example Conclusions Outline 1 Motivations Networked Control Systems Our Novelty 2 Problem Formulation NCS Configuration NCS Dynamics 3 Main Results Robust Stochastic Stability Synthesis

  2. Modeling the formation of globular cluster systems in the Virgo cluster

    SciTech Connect (OSTI)

    Li, Hui; Gnedin, Oleg Y. E-mail: ognedin@umich.edu

    2014-11-20

    The mass distribution and chemical composition of globular cluster (GC) systems preserve fossil record of the early stages of galaxy formation. The observed distribution of GC colors within massive early-type galaxies in the ACS Virgo Cluster Survey (ACSVCS) reveals a multi-modal shape, which likely corresponds to a multi-modal metallicity distribution. We present a simple model for the formation and disruption of GCs that aims to match the ACSVCS data. This model tests the hypothesis that GCs are formed during major mergers of gas-rich galaxies and inherit the metallicity of their hosts. To trace merger events, we use halo merger trees extracted from a large cosmological N-body simulation. We select 20 halos in the mass range of 2 × 10{sup 12} to 7 × 10{sup 13} M {sub ?} and match them to 19 Virgo galaxies with K-band luminosity between 3 × 10{sup 10} and 3 × 10{sup 11} L {sub ?}. To set the [Fe/H] abundances, we use an empirical galaxy mass-metallicity relation. We find that a minimal merger ratio of 1:3 best matches the observed cluster metallicity distribution. A characteristic bimodal shape appears because metal-rich GCs are produced by late mergers between massive halos, while metal-poor GCs are produced by collective merger activities of less massive hosts at early times. The model outcome is robust to alternative prescriptions for cluster formation rate throughout cosmic time, but a gradual evolution of the mass-metallicity relation with redshift appears to be necessary to match the observed cluster metallicities. We also affirm the age-metallicity relation, predicted by an earlier model, in which metal-rich clusters are systematically several billion younger than their metal-poor counterparts.

  3. Formation of gas-phase peroxides in a rural atmosphere: An interpretation of the recent SOS/SERON field results

    SciTech Connect (OSTI)

    Lee, J.H.; Tang, I.N. [Brookhaven National Lab., Upton, NY (United States); Weinstein-Lloyd, J.B. [State Univ. of New York, Old Westbury, NY (United States). Chemistry/Physics Dept.

    1993-09-01

    Hydrogen perioxide (H{sub 2}O{sub 2}) and certain organic peroxides such as hydroxymethyl-hydroperoxide (HMHP), are gas-phase oxidants present in the atmosphere at ppbv concentration levels. These oxidants play an important role in atmospheric chemistry. In addition, precipitation containing H{sub 2}O{sub 2} is toxic to trees, and it has also been suggested that organic peroxides formed presumably by ozone reactions with biogenic alkenes are responsible for leaf disorders. Recently, we have developed a nonenzymatic method or aqueous-phase H{sub 2}O{sub 2} measurement, using Fenton reagent and fluorescent hydroxy- benzoic acid. The new method, in conjunction with the well-known method of p-hydroxyphenylacetic acid and horseradish peroxidase for total peroxides, and together with an improved gas scrubber to mitigate sampling line problems, has been successfully deployed in recent SOS/SERON field measurements in rural Georgia. For the first time, continuously measured and speciated gas-phase peroxide data have become available, making it possible to examine some aspects of the ozone chemistry leading to the formation of these oxidants. It is observed that daily H{sub 2}O{sub 2} maximum frequently occurs at a different time than does HMHP, and that H{sub 2}O{sub 2} concentration, but not HMHP, tends to correlate with solar fluxes measured at the same location. These findings seem to indicate that the formation mechanisms for H{sub 2}O{sub 2} and organic peroxides are basically different. It is likely that H{sub 2}O{sub 2} is formed from radical-radical recombination, while HMHP is formed by ozone-alkene reactions. Since the gas-phase ozone-alkene reactions are usually too slow to account for the diurnal concentration variations observed for HMHP, heterogeneous processes involving ozone and alkenes are also a possibility.

  4. Modeling the formation and aging of secondary organic aerosols in Los Angeles during CalNex 2010

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

    Hayes, P. L.; Carlton, A. G.; Baker, K. R.; Ahmadov, R.; Washenfelder, R. A.; Alvarez, S.; Rappenglück, B.; Gilman, J. B.; Kuster, W. C.; de Gouw, J. A.; et al

    2015-05-26

    Four different literature parameterizations for the formation and evolution of urban secondary organic aerosol (SOA) frequently used in 3-D models are evaluated using a 0-D box model representing the Los Angeles metropolitan region during the California Research at the Nexus of Air Quality and Climate Change (CalNex) 2010 campaign. We constrain the model predictions with measurements from several platforms and compare predictions with particle- and gas-phase observations from the CalNex Pasadena ground site. That site provides a unique opportunity to study aerosol formation close to anthropogenic emission sources with limited recirculation. The model SOA that formed only from the oxidationmore »of VOCs (V-SOA) is insufficient to explain the observed SOA concentrations, even when using SOA parameterizations with multi-generation oxidation that produce much higher yields than have been observed in chamber experiments, or when increasing yields to their upper limit estimates accounting for recently reported losses of vapors to chamber walls. The Community Multiscale Air Quality (WRF-CMAQ) model (version 5.0.1) provides excellent predictions of secondary inorganic particle species but underestimates the observed SOA mass by a factor of 25 when an older VOC-only parameterization is used, which is consistent with many previous model–measurement comparisons for pre-2007 anthropogenic SOA modules in urban areas. Including SOA from primary semi-volatile and intermediate-volatility organic compounds (P-S/IVOCs) following the parameterizations of Robinson et al. (2007), Grieshop et al. (2009), or Pye and Seinfeld (2010) improves model–measurement agreement for mass concentration. The results from the three parameterizations show large differences (e.g., a factor of 3 in SOA mass) and are not well constrained, underscoring the current uncertainties in this area. Our results strongly suggest that other precursors besides VOCs, such as P-S/IVOCs, are needed to explain the observed SOA concentrations in Pasadena. All the recent parameterizations overpredict urban SOA formation at long photochemical ages (? 3 days) compared to observations from multiple sites, which can lead to problems in regional and especially global modeling. However, reducing IVOC emissions by one-half in the model to better match recent IVOC measurements improves SOA predictions at these long photochemical ages. Among the explicitly modeled VOCs, the precursor compounds that contribute the greatest SOA mass are methylbenzenes. Measured polycyclic aromatic hydrocarbons (naphthalenes) contribute 0.7% of the modeled SOA mass. The amounts of SOA mass from diesel vehicles, gasoline vehicles, and cooking emissions are estimated to be 16–27, 35–61, and 19–35%, respectively, depending on the parameterization used, which is consistent with the observed fossil fraction of urban SOA, 71(±3) %. The relative contribution of each source is uncertain by almost a factor of 2 depending on the parameterization used. In-basin biogenic VOCs are predicted to contribute only a few percent to SOA. A regional SOA background of approximately 2.1 ?g m?3 is also present due to the long-distance transport of highly aged OA, likely with a substantial contribution from regional biogenic SOA. The percentage of SOA from diesel vehicle emissions is the same, within the estimated uncertainty, as reported in previous work that analyzed the weekly cycles in OA concentrations (Bahreini et al., 2012; Hayes et al., 2013). However, the modeling work presented here suggests a strong anthropogenic source of modern carbon in SOA, due to cooking emissions, which was not accounted for in those previous studies and which is higher on weekends. Lastly, this work adapts a simple two-parameter model to predict SOA concentration and O/C from urban emissions. This model successfully predicts SOA concentration, and the optimal parameter combination is very similar to that found for Mexico City. This approach provides a computationally inexpensive method for predicting urban SOA in global

  5. Motivation Modelling the CMD Making Inference Results Conclusion Ages of stellar populations from color-magnitude

    E-Print Network [OSTI]

    Wolfe, Patrick J.

    Motivation Modelling the CMD Making Inference Results Conclusion Ages of stellar populations from Baines 093008 #12;Motivation Modelling the CMD Making Inference Results Conclusion Context & Example) guide to the Astronomy behind it. Paul Baines 093008 #12;#12;Motivation Modelling the CMD Making

  6. THE FORMATION OF IRIS DIAGNOSTICS. I. A QUINTESSENTIAL MODEL ATOM OF Mg II AND GENERAL FORMATION PROPERTIES OF THE Mg II h and k LINES

    SciTech Connect (OSTI)

    Leenaarts, J.; Pereira, T. M. D.; Carlsson, M.; De Pontieu, B. [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029, Blindern, N-0315 Oslo (Norway); Uitenbroek, H., E-mail: jorritl@astro.uio.no, E-mail: tiago.pereira@astro.uio.no, E-mail: mats.carlsson@astro.uio.no, E-mail: bdp@lmsal.com, E-mail: huitenbroek@nso.edu [NSO/Sacramento Peak, P.O. Box 62, Sunspot, NM 88349-0062 (United States)

    2013-08-01

    NASA's Interface Region Imaging Spectrograph (IRIS) space mission will study how the solar atmosphere is energized. IRIS contains an imaging spectrograph that covers the Mg II h and k lines as well as a slit-jaw imager centered at Mg II k. Understanding the observations will require forward modeling of Mg II h and k line formation from three-dimensional (3D) radiation-MHD models. This paper is the first in a series where we undertake this forward modeling. We discuss the atomic physics pertinent to h and k line formation, present a quintessential model atom that can be used in radiative transfer computations, and discuss the effect of partial redistribution (PRD) and 3D radiative transfer on the emergent line profiles. We conclude that Mg II h and k can be modeled accurately with a four-level plus continuum Mg II model atom. Ideally radiative transfer computations should be done in 3D including PRD effects. In practice this is currently not possible. A reasonable compromise is to use one-dimensional PRD computations to model the line profile up to and including the central emission peaks, and use 3D transfer assuming complete redistribution to model the central depression.

  7. Leaching of BTEX from Aged Crude Oil Contaminated Model Soils: Experimental and Modeling Results

    SciTech Connect (OSTI)

    Huesemann, Michael H.; Hausmann, Tom S.; Fortman, Timothy J.

    2005-01-01

    It is generally assumed that soil properties such as organic matter content, porosity, and mineral surface area have a significant effect on the bioavailability and leachability of aged petroleum hydrocarbons. In order to test this hypothesis, nine model soils or sorbents (i.e., fine and coarse quartz sand, montmorillonite and kaolinite clay, peat, 60? and 150? silica gel, a loam soil, and non-porous glass beads) were spiked with a crude oil, aged for 27 months in the laboratory, and transferred to glass columns for the performance of continuous flow leaching experiments. The column effluents were periodically sampled for 43 days and analyzed for BTEX. A one-dimensional flow model for predicting the dissolution and dispersion of individual hydrocarbons from a multi-component NAPL such as crude oil was used to fit the leaching data (i.e., the BTEX concentration versus time curves) by adjusting the equilibrium oil-leachate partitioning coefficient (Kol) for each respective hydrocarbon. The Peclet number, which is a measure of dispersion and a required modeling parameter, was measured in separate chloride tracer experiments for each soil column. Results demonstrate that soil properties did not significantly affect the leaching kinetics of BTEX from the columns. Instead, BTEX leaching curves could be successfully fitted with the one-dimensional NAPL dissolution flow model for all sorbents with the exception of montmorillonite clay. The fitting parameter Kol for each hydrocarbon was found to be similar to the Kol values that were independently measured for the same crude oil by Rixey et al. (Journal of Hazardous Materials B, 65: 137-156, 1999). In addition, the fitted Kol values were very similar for BTEX leaching from aged compared to freshly spiked loam soil. These findings indicate that leaching of BTEX in the aged soils that are contaminated with crude oil at the high concentrations commonly found in the environment (i.e., >20,000 mg/kg) was not affected by soil properties or aging but rather was governed by the equilibrium dissolution of these hydrocarbons from the crude oil NAPL that is coating the soil particles.

  8. Modeling of Reoxidation Inclusion Formation in Steel Sand Casting K.D. Carlson, A.J. Melendez and C. Beckermann

    E-Print Network [OSTI]

    Beckermann, Christoph

    1 Modeling of Reoxidation Inclusion Formation in Steel Sand Casting K.D. Carlson, A.J. Melendez, as well as their final locations on the surface of steel sand castings. Inclusions originate on the melt. The inclusion model is implemented in a general-purpose casting simulation code. The model is validated

  9. Long-time evolution of models of aeolian sand dune fields: Influence of dune formation and collision

    E-Print Network [OSTI]

    Glasner, Karl B.

    Long-time evolution of models of aeolian sand dune fields: Influence of dune formation December 2008 Accepted 6 February 2009 Available online xxxx Keywords: Sand dune Dune field Dune field model Dune collision Coarsening Coalescence Theoretical models which approximate individual sand dunes

  10. Two-dimensional model problem to explain counter-rotating vortex pair formation in a transverse jet

    E-Print Network [OSTI]

    Mahesh, Krishnan

    Two-dimensional model problem to explain counter-rotating vortex pair formation in a transverse jet A two-dimensional model problem is used to study the evolution of the cross section of a transverse jet and the counter-rotating vortex pair CVP . The solution to the model problem shows deformation of the jet similar

  11. Formation and eruption of an active region sigmoid. I. A study by nonlinear force-free field modeling

    SciTech Connect (OSTI)

    Jiang, Chaowei; Feng, Xueshang [SIGMA Weather Group, State Key Laboratory for Space Weather, Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100190 (China); Wu, S. T.; Hu, Qiang, E-mail: cwjiang@spaceweather.ac.cn, E-mail: fengx@spaceweather.ac.cn, E-mail: wus@uah.edu, E-mail: qh0001@uah.edu [Center for Space Plasma and Aeronomic Research, The University of Alabama in Huntsville, Huntsville, AL 35899 (United States)

    2014-01-01

    We present a comprehensive study of the formation and eruption of an active region (AR) sigmoid in AR 11283. To follow the quasi-static evolution of the coronal magnetic field, we reconstruct a time sequence of static fields using a recently developed nonlinear force-free field model constrained by vector magnetograms. A detailed analysis of the fields compared with observations suggests the following scenario for the evolution of the region. Initially, a new bipole emerges into the negative polarity of a preexisting bipolar AR, forming a null-point topology between the two flux systems. A weakly twisted flux rope (FR) is then built up slowly in the embedded core region, largely through flux cancellation, forming a bald patch separatrix surface (BPSS). The FR grows gradually until its axis runs into a torus instability (TI) domain, and the BPSS also develops a full S-shape. The combined effects of the TI-driven expansion of the FR and the line tying at the BP tear the FR into two parts with the upper portion freely expelled and the lower portion remaining behind the postflare arcades. This process dynamically perturbs the BPSS and results in the enhanced heating of the sigmoid and the rope. The accelerated expansion of the upper-portion rope strongly pushes its envelope flux near the null point and triggers breakout reconnection at the null, which further drives the eruption. We discuss the important implications of these results for the formation and disruption of the sigmoid region with an FR.

  12. Improved Building Energy Performance Modelling through Comparison of Measured Data with Simulated Results 

    E-Print Network [OSTI]

    Bambrook, S.; Jacob, D.

    2008-01-01

    the building and comparing simulated results to the measured data. The simulated building energy performance results achieved in the first stage of computer modelling show a reasonable correlation with measured data, however, further work is required to create...

  13. Modeling the formation and aging of secondary organic aerosols in Los Angeles during CalNex 2010

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

    Hayes, P. L.; Carlton, A. G.; Baker, K. R.; Ahmadov, R.; Washenfelder, R. A.; Alvarez, S.; Rappenglück, B.; Gilman, J. B.; Kuster, W. C.; de Gouw, J. A.; et al

    2014-12-20

    Four different parameterizations for the formation and evolution of secondary organic aerosol (SOA) are evaluated using a 0-D box model representing the Los Angeles Metropolitan Region during the CalNex 2010 field campaign. We constrain the model predictions with measurements from several platforms and compare predictions with particle and gas-phase observations from the CalNex Pasadena ground site. That site provides a unique opportunity to study aerosol formation close to anthropogenic emission sources with limited recirculation. The model SOA formed only from the oxidation of VOCs (V-SOA) is insufficient to explain the observed SOA concentrations, even when using SOA parameterizations with multi-generationmore »oxidation that produce much higher yields than have been observed in chamber experiments, or when increasing yields to their upper limit estimates accounting for recently reported losses of vapors to chamber walls. The Community Multiscale Air Quality (WRF-CMAQ) model (version 5.0.1) provides excellent predictions of secondary inorganic particle species but underestimates the observed SOA mass by a factor of 25 when an older VOC-only parameterization is used, which is consistent with many previous model-measurement comparisons for pre-2007 anthropogenic SOA modules in urban areas. Including SOA from primary semi-volatile and intermediate volatility organic compounds (P-S/IVOCs) following the parameterizations of Robinson et al. (2007), Grieshop et al. (2009), or Pye and Seinfeld (2010) improves model/measurement agreement for mass concentration. When comparing the three parameterizations, the Grieshop et al. (2009) parameterization more accurately reproduces both the SOA mass concentration and oxygen-to-carbon ratio inside the urban area. Our results strongly suggest that other precursors besides VOCs, such as P-S/IVOCs, are needed to explain the observed SOA concentrations in Pasadena. All the parameterizations over-predict urban SOA formation at long photochemical ages (≈ 3 days) compared to observations from multiple sites, which can lead to problems in regional and global modeling. Among the explicitly modeled VOCs, the precursor compounds that contribute the greatest SOA mass are methylbenzenes. Polycyclic aromatic hydrocarbons (PAHs) are less important precursors and contribute less than 4% of the SOA mass. The amounts of SOA mass from diesel vehicles, gasoline vehicles, and cooking emissions are estimated to be 16–27, 35–61, and 19–35%, respectively, depending on the parameterization used, which is consistent with the observed fossil fraction of urban SOA, 71 (±3) %. In-basin biogenic VOCs are predicted to contribute only a few percent to SOA. A regional SOA background of approximately 2.1 ?g m?3 is also present due to the long distance transport of highly aged OA. The percentage of SOA from diesel vehicle emissions is the same, within the estimated uncertainty, as reported in previous work that analyzed the weekly cycles in OA concentrations (Bahreini et al., 2012; Hayes et al., 2013). However, the modeling work presented here suggests a strong anthropogenic source of modern carbon in SOA, due to cooking emissions, which was not accounted for in those previous studies. Lastly, this work adapts a simple two-parameter model to predict SOA concentration and O/C from urban emissions. This model successfully predicts SOA concentration, and the optimal parameter combination is very similar to that found for Mexico City. This approach provides a computationally inexpensive method for predicting urban SOA in global and climate models. We estimate pollution SOA to account for 26 Tg yr?1 of SOA globally, or 17% of global SOA, 1/3 of which is likely to be non-fossil.« less

  14. SBML qualitative models: a model representation format and infrastructure to foster interactions between qualitative modelling formalisms and tools

    E-Print Network [OSTI]

    2013-01-01

    C: Petri net modelling of biological networks. BriefPetri net framework to investigate biomolecular networks.in Boolean networks, logical models and some Petri nets

  15. HOT X-RAY CORONAE AROUND MASSIVE SPIRAL GALAXIES: A UNIQUE PROBE OF STRUCTURE FORMATION MODELS

    SciTech Connect (OSTI)

    Bogdan, Akos; Forman, William R.; Vogelsberger, Mark; Sijacki, Debora; Mazzotta, Pasquale; Kraft, Ralph P.; Jones, Christine; David, Laurence P. [Harvard Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Bourdin, Herve [Dipartimento di Fisica, Universita degli Studi di Roma 'Tor Vergata', via della Ricerca Scientifica 1, I-00133 Roma (Italy); Gilfanov, Marat; Churazov, Eugene, E-mail: abogdan@cfa.harvard.edu [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-str. 1, D-85748 Garching (Germany)

    2013-08-01

    Luminous X-ray gas coronae in the dark matter halos of massive spiral galaxies are a fundamental prediction of structure formation models, yet only a few such coronae have been detected so far. In this paper, we study the hot X-ray coronae beyond the optical disks of two 'normal' massive spirals, NGC 1961 and NGC 6753. Based on XMM-Newton X-ray observations, hot gaseous emission is detected to {approx}60 kpc-well beyond their optical radii. The hot gas has a best-fit temperature of kT {approx} 0.6 keV and an abundance of {approx}0.1 Solar, and exhibits a fairly uniform distribution, suggesting that the quasi-static gas resides in hydrostatic equilibrium in the potential well of the galaxies. The bolometric luminosity of the gas in the (0.05-0.15)r{sub 200} region (r{sub 200} is the virial radius) is {approx}6 Multiplication-Sign 10{sup 40} erg s{sup -1} for both galaxies. The baryon mass fractions of NGC 1961 and NGC 6753 are f{sub b,NGC1961} {approx} 0.11 and f{sub b,NGC6753} {approx} 0.09, which values fall short of the cosmic baryon fraction. The hot coronae around NGC 1961 and NGC 6753 offer an excellent basis to probe structure formation simulations. To this end, the observations are confronted with the moving mesh code AREPO and the smoothed particle hydrodynamics code GADGET. Although neither model gives a perfect description, the observed luminosities, gas masses, and abundances favor the AREPO code. Moreover, the shape and the normalization of the observed density profiles are better reproduced by AREPO within {approx}0.5r{sub 200}. However, neither model incorporates efficient feedback from supermassive black holes or supernovae, which could alter the simulated properties of the X-ray coronae. With the further advance of numerical models, the present observations will be essential in constraining the feedback effects in structure formation simulations.

  16. Haptic Models of an Automotive Turn-Signal Switch: Identification and Playback Results

    E-Print Network [OSTI]

    Hollerbach, John M.

    Haptic Models of an Automotive Turn-Signal Switch: Identification and Playback Results Mark B of virtual environments. This paper addresses the problem of modeling the feel of an automotive turn- signal would require accurate models of the primary automotive controls, including the steering wheel, gear

  17. Conceptual model for transport processes in the Culebra Dolomite Member, Rustler Formation

    SciTech Connect (OSTI)

    Holt, R.M. [Holt Hydrogeology, Placitas, NM (United States)] [Holt Hydrogeology, Placitas, NM (United States)

    1997-08-01

    The Culebra Dolomite Member of the Rustler Formation represents a possible pathway for contaminants from the Waste Isolation Pilot Plant underground repository to the accessible environment. The geologic character of the Culebra is consistent with a double-porosity, multiple-rate model for transport in which the medium is conceptualized as consisting of advective porosity, where solutes are carried by the groundwater flow, and fracture-bounded zones of diffusive porosity, where solutes move through slow advection or diffusion. As the advective travel length or travel time increases, the nature of transport within a double-porosity medium changes. This behavior is important for chemical sorption, because the specific surface area per unit mass of the diffusive porosity is much greater than in the advective porosity. Culebra transport experiments conducted at two different length scales show behavior consistent with a multiple-rate, double-porosity conceptual model for Culebra transport. Tracer tests conducted on intact core samples from the Culebra show no evidence of significant diffusion, suggesting that at the core scale the Culebra can be modeled as a single-porosity medium where only the advective porosity participates in transport. Field tracer tests conducted in the Culebra show strong double-porosity behavior that is best explained using a multiple-rate model.

  18. Cost Benefit Analysis Modeling Tool for Electric vs. ICE Airport Ground Support Equipment – Development and Results

    SciTech Connect (OSTI)

    James Francfort; Kevin Morrow; Dimitri Hochard

    2007-02-01

    This report documents efforts to develop a computer tool for modeling the economic payback for comparative airport ground support equipment (GSE) that are propelled by either electric motors or gasoline and diesel engines. The types of GSE modeled are pushback tractors, baggage tractors, and belt loaders. The GSE modeling tool includes an emissions module that estimates the amount of tailpipe emissions saved by replacing internal combustion engine GSE with electric GSE. This report contains modeling assumptions, methodology, a user’s manual, and modeling results. The model was developed based on the operations of two airlines at four United States airports.

  19. A Kinetic Monte Carlo model for material aging: Simulations of second phase formation at Au/Bi{sub 2}Te{sub 3} junction in oxygen environments

    SciTech Connect (OSTI)

    Zhou, X. W., E-mail: xzhou@sandia.gov [Mechanics of Materials Department, Sandia National Laboratories, Livermore, California 94550 (United States); Yang, N. Y. C. [Energy Nanomaterials Department, Sandia National Laboratories, Livermore, California 94550 (United States)

    2014-03-14

    Electronic properties of semiconductor devices are sensitive to defects such as second phase precipitates, grain sizes, and voids. These defects can evolve over time especially under oxidation environments and it is therefore important to understand the resulting aging behavior in order for the reliable applications of devices. In this paper, we propose a kinetic Monte Carlo framework capable of simultaneous simulation of the evolution of second phases, precipitates, grain sizes, and voids in complicated systems involving many species including oxygen. This kinetic Monte Carlo model calculates the energy barriers of various events based directly on the experimental data. As a first step of our model implementation, we incorporate the second phase formation module in the parallel kinetic Monte Carlo codes SPPARKS. Selected aging simulations are performed to examine the formation of second phase precipitates at the eletroplated Au/Bi{sub 2}Te{sub 3} interface under oxygen and oxygen-free environments, and the results are compared with the corresponding experiments.

  20. A Model Incorporating Some of the Mechanical and Biochemical Factors Underlying Clot Formation and Dissolution in Flowing Blood

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

    Anand, M.; Rajagopal, K.; Rajagopal, K. R.

    2003-01-01

    Multiple interacting mechanisms control the formation and dissolution of clots to maintain blood in a state of delicate balance. In addition to a myriad of biochemical reactions, rheological factors also play a crucial role in modulating the response of blood to external stimuli. To date, a comprehensive model for clot formation and dissolution, that takes into account the biochemical, medical and rheological factors, has not been put into place, the existing models emphasizing either one or the other of the factors. In this paper, after discussing the various biochemical, physiologic and rheological factors at some length, we develop a modelmore »for clot formation and dissolution that incorporates many of the relevant crucial factors that have a bearing on the problem. The model, though just a first step towards understanding a complex phenomenon, goes further than previous models in integrating the biochemical, physiologic and rheological factors that come into play.« less

  1. Source Contributions to VOC's to Ozone Formation in Southeast Texas Using a Source-oriented Air Quality Model 

    E-Print Network [OSTI]

    Krishnan, Anupama

    2011-08-08

    and petrochemical industries to ozone formation in the atmosphere. Source-oriented emissions needed to drive the model were generated using a revised Sparse Matrix Operator Kernel Emissions (SMOKE) model version 2.4. VOC/NOx ratios are found to be a critical factor...

  2. Modeling of the formation of short-chain acids in propane flames F. Battin-Leclerc , 1

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Modeling of the formation of short-chain acids in propane flames F. Battin-Leclerc , 1 , A. Simulations of lean (equivalence ratios from 0.9 to 0.48) laminar premixed flames of propane stabilized in a combustion apparatus which can easily be modeled, a laminar premixed flame of propane at atmospheric pressure

  3. Deriving star formation histories from photometry using energy balance spectral energy distribution modelling

    E-Print Network [OSTI]

    Smith, Daniel J B

    2015-01-01

    Panchromatic spectral energy distribution (SED) fitting is a critical tool for determining the physical properties of distant galaxies, such as their stellar mass and star formation rate. One widely used method is the publicly available MAGPHYS code. We build on our previous analysis (Hayward & Smith 2015) by presenting some modifications which enable MAGPHYS to automatically estimate galaxy star formation histories (SFHs), including uncertainties, based on ultra-violet to far-infrared photometry. We use state-of-the art synthetic photometry derived by performing three-dimensional dust radiative transfer on hydrodynamic simulations of isolated disc and merging galaxies to test how well the modified MAGPHYS is able to recover SFHs under idealised conditions, where the true SFH is known. We find that while the SFH of the model with the best fit to the synthetic photometry is a poor representation of the true SFH (showing large variations with the line-of-sight to the galaxy and spurious bursts of star forma...

  4. A comparison of chemistry and dust cloud formation in ultracool dwarf model atmospheres

    E-Print Network [OSTI]

    Ch. Helling; A. Ackerman; F. Allard; M. Dehn; P. Hauschildt; D. Homeier; K. Lodders; M. Marley; F. Rietmeijer; T. Tsuji; P. Woitke

    2008-09-24

    The atmospheres of substellar objects contain clouds of oxides, iron, silicates, and other refractory condensates. Water clouds are expected in the coolest objects. The opacity of these `dust' clouds strongly affects both the atmospheric temperature-pressure profile and the emergent flux. Thus any attempt to model the spectra of these atmospheres must incorporate a cloud model. However the diversity of cloud models in atmospheric simulations is large and it is not always clear how the underlying physics of the various models compare. Likewise the observational consequences of different modeling approaches can be masked by other model differences, making objective comparisons challenging. In order to clarify the current state of the modeling approaches, this paper compares five different cloud models in two sets of tests. Test case 1 tests the dust cloud models for a prescribed L, L--T, and T-dwarf atmospheric (temperature T, pressure p, convective velocity vconv)-structures. Test case 2 compares complete model atmosphere results for given (effective temperature Teff, surface gravity log g). All models agree on the global cloud structure but differ in opacity-relevant details like grain size, amount of dust, dust and gas-phase composition. Comparisons of synthetic photometric fluxes translate into an modelling uncertainty in apparent magnitudes for our L-dwarf (T-dwarf) test case of 0.25 < \\Delta m < 0.875 (0.1 < \\Delta m M 1.375) taking into account the 2MASS, the UKIRT WFCAM, the Spitzer IRAC, and VLT VISIR filters with UKIRT WFCAM being the most challenging for the models. (abr.)

  5. A continental clastic depositional model for the Permian Unayzah formation, Hawtah field, central Saudi Arabia

    SciTech Connect (OSTI)

    Heine, C.J. (Saudi Aramco, Dhahran (Saudi Arabia))

    1993-09-01

    The Permian Unayzah Formation lies unconformably on the Silurian Qusaiba Member of the Qalibah Formation. The pre-Unayzah unconformity (PUU) represents a Hercynian tectonic event responsible for uplift and erosion representing 100-150 m.y. worth of missing section along the Hawtah Trend. Overlying the PUU, the Unayzah clastic sequence is comprised of locally sourced sediments from the adjacent paleotopography. Above the thin veneer of locally sourced sediments is a more regionally sourced, confined braided stream sequence, which completely backfills the existing paleotopography. Once the paleotopographic surface had been leveled, the depositional environment changed from a confined braided stream to a broad braided plain. Within this sequence of vertically stacked and laterally migrating braided plain sediments, the bulk of the reservoirs within the Hawtah field are contained. As the transgressive Khuff seas continue to encroach on the Unayzah depositional system, the upper-most sediments of the broad braided plan environment are reworked by transgressive coastal processes. The resulting reworked shoreface and shallow-marine facies are genetically related to the Khuff transgression and lie unconformably on the Unayzah continental clastics.

  6. Modeling of the formation of short-chain acids in propane flames

    E-Print Network [OSTI]

    Battin-Leclerc, Frédérique; Jaffrezo, J L; Legrand, M

    2009-01-01

    In order to better understand their potential formation in combustion systems, a detailed kinetic mechanism for the formation of short-chain monocarboxylic acids, formic (HCOOH), acetic (CH3COOH), propionic (C2H5COOH) and propenic (C2H3COOH)) acids, has been developed. Simulations of lean (equivalence ratios from 0.9 to 0.48) laminar premixed flames of propane stabilized at atmospheric pressure with nitrogen as diluent have been performed. It was found that amounts up to 25 ppm of acetic acid, 15 ppm of formic acid and 1 ppm of C3 acid can be formed for some positions in the flames. Simulations showed that the more abundant C3 acid formed is propenic acid. A quite acceptable agreement has been obtained with the scarce results from the literature concerning oxygenated compounds, including aldehydes (CH2O, CH3CHO) and acids. A reaction pathways analysis demonstrated that each acid is mainly derived from the aldehyde of similar structure.

  7. QGP time formation in holographic shock waves model of heavy ion collisions

    E-Print Network [OSTI]

    Aref'eva, Irina Ya

    2015-01-01

    We estimate the thermalization time in two colliding shock waves holographic model of heavy-ion collisions. For this purpose we model the process by the Vaidya metric with a horizon defined by the trapped surface location. We consider two bottom-up AdS/QCD models that give, within the colliding shock waves approach, the dependence of multiplicity on the energy compatible with RHIC and LHC results. One model is a bottom-up AdS/QCD confining model and the other is related to an anisotropic thermalization. We estimate the thermalization time and show that increasing the confining potential decreases the thermalization time as well as an anisotropy accelerates the thermalization.

  8. QGP time formation in holographic shock waves model of heavy ion collisions

    E-Print Network [OSTI]

    Irina Ya. Aref'eva

    2015-03-07

    We estimate the thermalization time in two colliding shock waves holographic model of heavy-ion collisions. For this purpose we model the process by the Vaidya metric with a horizon defined by the trapped surface location. We consider two bottom-up AdS/QCD models that give, within the colliding shock waves approach, the dependence of multiplicity on the energy compatible with RHIC and LHC results. One model is a bottom-up AdS/QCD confining model and the other is related to an anisotropic thermalization. We estimate the thermalization time and show that increasing the confining potential decreases the thermalization time as well as an anisotropy accelerates the thermalization.

  9. Integrated Assessment Modeling of Carbon Sequestration and Land Use Emissions Using Detailed Model Results and Observations

    SciTech Connect (OSTI)

    Dr. Atul Jain

    2005-04-17

    This report outlines the progress on the development and application of Integrated Assessment Modeling of Carbon Sequestrations and Land Use Emissions supported by the DOE Office of Biological and Environmental Research (OBER), U.S. Department of Energy, Grant No. DOE-DE-FG02-01ER63069. The overall objective of this collaborative project between the University of Illinois at Urbana-Champaign (UIUC), Oak Ridge National Laboratory (ORNL), Lawrence Livermore National Laboratory (LLNL), and Pacific Northwest National Laboratory (PNNL) was to unite the latest advances in carbon cycle research with scientifically based models and policy-related integrated assessment tools that incorporate computationally efficient representations of the latest knowledge concerning science and emission trajectories, and their policy implications. As part of this research we accomplished the following tasks that we originally proposed: (1) In coordination with LLNL and ORNL, we enhanced the Integrated Science Assessment Model's (ISAM) parametric representation of the ocean and terrestrial carbon cycles that better represent spatial and seasonal variations, which are important to study the mechanisms that influence carbon sequestration in the ocean and terrestrial ecosystems; (2) Using the MiniCAM modeling capability, we revised the SRES (IPCC Special Report on Emission Scenarios; IPCC, 2000) land use emission scenarios; and (3) On the application front, the enhanced version of ISAM modeling capability is applied to understand how short- and long-term natural carbon fluxes, carbon sequestration, and human emissions contribute to the net global emissions (concentrations) trajectories required to reach various concentration (emission) targets. Under this grant, 21 research publications were produced. In addition, this grant supported a number of graduate and undergraduate students whose fundamental research was to learn a disciplinary field in climate change (e.g., ecological dynamics and ocean circulations) and then complete research on how this field could be linked to the other factors we need to consider in its dynamics (e.g., land use, ocean and terrestrial carbon sequestration and climate change).

  10. 2D-Modelling of pellet injection in the poloidal plane: results of numerical tests

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    2D-Modelling of pellet injection in the poloidal plane: results of numerical tests P. Lalousis developed for computing the expansion of pellet-produced clouds in the poloidal plane. The expansion

  11. Global sea-salt modeling: Results and validation against multicampaign shipboard measurements

    E-Print Network [OSTI]

    Global sea-salt modeling: Results and validation against multicampaign shipboard measurements of sea-salt concentrations from five different campaigns are used to validate the sea-salt). The validity of the sea-salt parameterizations is tested by employing a global forecasting model and transport

  12. Combinatorial Algorithms for Protein Folding in Lattice Models: A Survey of Mathematical Results

    E-Print Network [OSTI]

    Istrail, Sorin

    Combinatorial Algorithms for Protein Folding in Lattice Models: A Survey of Mathematical Results a comprehensive survey of combinatorial algorithms and theorems about lattice protein folding models obtained in the almost 15 years since the publication in 1995 of the first protein folding approximation algorithm

  13. CLIMATE SCIENCE The Community Climate System Model results from a multi-agency collaboration

    E-Print Network [OSTI]

    Long, Nicholas

    . Thus, climate science--which by nature involves advanced computing technology and methods--has beenCLIMATE SCIENCE The Community Climate System Model results from a multi-agency collaboration designed to construct cutting-edge climate science simulation models for a broad research community

  14. Tetrahedral collapse: a rotational toy model of simultaneous dark-matter halo, filament and wall formation

    E-Print Network [OSTI]

    Neyrinck, Mark C

    2015-01-01

    We discuss an idealized model of halo formation, in which a collapsing halo node is tetrahedral, with a filament extruding from each of its four faces, and with a wall connecting each pair of filaments. In the model, filaments generally spin when they form, and the halo spins if and only if there is some rotation in filaments. This is the simplest-possible fully three-dimensional halo collapse in the 'origami approximation,' in which voids are irrotational, and the dark-matter sheet out of which dark-matter structures form is allowed to fold in position-velocity phase space, but not stretch (i.e., it cannot vary in density along a stream). Up to an overall scaling, the four filament directions, and only three other quantities, such as filament spins, suffice to determine all of the collapse's properties: the shape, mass, and spin of the halo; the densities per unit length and spins of all filaments; and masses per unit area of the walls. If the filaments are arranged regular-tetrahedrally, filament properties...

  15. Results and Comparison from the SAM Linear Fresnel Technology Performance Model: Preprint

    SciTech Connect (OSTI)

    Wagner, M. J.

    2012-04-01

    This paper presents the new Linear Fresnel technology performance model in NREL's System Advisor Model. The model predicts the financial and technical performance of direct-steam-generation Linear Fresnel power plants, and can be used to analyze a range of system configurations. This paper presents a brief discussion of the model formulation and motivation, and provides extensive discussion of the model performance and financial results. The Linear Fresnel technology is also compared to other concentrating solar power technologies in both qualitative and quantitative measures. The Linear Fresnel model - developed in conjunction with the Electric Power Research Institute - provides users with the ability to model a variety of solar field layouts, fossil backup configurations, thermal receiver designs, and steam generation conditions. This flexibility aims to encompass current market solutions for the DSG Linear Fresnel technology, which is seeing increasing exposure in fossil plant augmentation and stand-alone power generation applications.

  16. Models of the formation of oxide phases in nanostructured materials based on lead chalcogenides subjected to treatment in oxygen and iodine vapors

    SciTech Connect (OSTI)

    Maraeva, E. V., E-mail: jenvmar@mail.ru; Moshnikov, V. A.; Tairov, Yu. M. [St. Petersburg State Electrotechnical University 'LETI' (Russian Federation)] [St. Petersburg State Electrotechnical University 'LETI' (Russian Federation)

    2013-10-15

    Model concepts concerning control over the formation of oxide layers during the course of oxidation are developed on the basis of experimental results of studies of systematic features of the formation of nanostructured layers after diffusion annealing. Data on a variation in the composition of oxide phases as the extent of deviation from stoichiometry is changed in the initial lead chalcogenide are presented. Model concepts related to the possibility of varying the thickness of the coating oxide phases using annealing in an oxygen-containing medium are developed. It is shown that annealing in an iodine atmosphere ensures the effective penetration of oxygen into the grains, which is necessary for an increase in the photoluminescence efficiency.

  17. Modeling the Inhomogeneous Response and Formation of Shear Bands in Steady and

    E-Print Network [OSTI]

    of these models, the `flow curve' of stress and apparent shear rate resulting from an assumption of homogeneous de of Machanical Engineering, MIT 1 #12;1 Introduction A central assumption behind rheometry is that the velocity shampoos and body gels; in the petroleum industry they are used in fracturing operations and enhanced oil

  18. COMPUTATIONAL FLUID DYNAMICS MODELING OF SCALED HANFORD DOUBLE SHELL TANK MIXING - CFD MODELING SENSITIVITY STUDY RESULTS

    SciTech Connect (OSTI)

    JACKSON VL

    2011-08-31

    The primary purpose of the tank mixing and sampling demonstration program is to mitigate the technical risks associated with the ability of the Hanford tank farm delivery and celtification systems to measure and deliver a uniformly mixed high-level waste (HLW) feed to the Waste Treatment and Immobilization Plant (WTP) Uniform feed to the WTP is a requirement of 24590-WTP-ICD-MG-01-019, ICD-19 - Interface Control Document for Waste Feed, although the exact definition of uniform is evolving in this context. Computational Fluid Dynamics (CFD) modeling has been used to assist in evaluating scaleup issues, study operational parameters, and predict mixing performance at full-scale.

  19. Summary Results for Brine Migration Modeling Performed by LANL LBNL and SNL for the UFD Program.

    SciTech Connect (OSTI)

    Kuhlman, Kristopher L

    2014-09-01

    This report summarizes laboratory and field observations and numerical modeling related to coupled processes involving brine and vapor migration in geologic salt, focusing on recent developments and studies conducted at Sandia, Los Alamos, and Berkeley National Laboratories. Interest into the disposal of heat-generating waste in salt has led to interest into water distribution and migration in both run-of-mine crushed and intact geologic salt. Ideally a fully coupled thermal-hydraulic-mechanical-chemical simulation is performed using numerical models with validated constitutive models and parameters. When mechanical coupling is not available, mechanical effects are prescribed in hydraulic models as source, boundary, or initial conditions. This report presents material associated with developing appropriate initial conditions for a non-mechanical hydrologic simulation of brine migration in salt. Due to the strong coupling between the mechanical and hydrologic problems, the initial saturation will be low for the excavation disturbed zone surrounding the excavation. Although most of the material in this report is not new, the author hopes it is presented in a format making it useful to other salt researchers.

  20. Constitutive models for the Etchegoin Sands, Belridge Diatomite, and overburden formations at the Lost Hills oil field, California

    SciTech Connect (OSTI)

    FOSSUM,ARLO F.; FREDRICH,JOANNE T.

    2000-04-01

    This report documents the development of constitutive material models for the overburden formations, reservoir formations, and underlying strata at the Lost Hills oil field located about 45 miles northwest of Bakersfield in Kern County, California. Triaxial rock mechanics tests were performed on specimens prepared from cores recovered from the Lost Hills field, and included measurements of axial and radial stresses and strains under different load paths. The tested intervals comprise diatomaceous sands of the Etchegoin Formation and several diatomite types of the Belridge Diatomite Member of the Monterey Formation, including cycles both above and below the diagenetic phase boundary between opal-A and opal-CT. The laboratory data are used to drive constitutive parameters for the Extended Sandler-Rubin (ESR) cap model that is implemented in Sandia's structural mechanics finite element code JAS3D. Available data in the literature are also used to derive ESR shear failure parameters for overburden formations. The material models are being used in large-scale three-dimensional geomechanical simulations of the reservoir behavior during primary and secondary recovery.

  1. RETENTION OF A PRIMORDIAL COLD CLASSICAL KUIPER BELT IN AN INSTABILITY-DRIVEN MODEL OF SOLAR SYSTEM FORMATION

    SciTech Connect (OSTI)

    Batygin, Konstantin; Brown, Michael E.; Fraser, Wesley C., E-mail: kbatygin@gps.caltech.edu [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States)

    2011-09-01

    The cold classical population of the Kuiper Belt exhibits a wide variety of unique physical characteristics, which collectively suggest that its dynamical coherence has been maintained throughout the solar system's lifetime. Simultaneously, the retention of the cold population's relatively unexcited orbital state has remained a mystery, especially in the context of a solar system formation model, that is driven by a transient period of instability, where Neptune is temporarily eccentric. Here, we show that the cold belt can survive the instability, and its dynamical structure can be reproduced. We develop a simple analytical model for secular excitation of cold Kuiper Belt objects and show that comparatively fast apsidal precession and nodal recession of Neptune, during the eccentric phase, are essential for preservation of an unexcited state in the cold classical region. Subsequently, we confirm our results with self-consistent N-body simulations. We further show that contamination of the hot classical and scattered populations by objects of similar nature to that of cold classicals has been instrumental in shaping the vast physical diversity inherent to the Kuiper Belt.

  2. Self-consistent three-dimensional model of dust particle transport and formation of Coulomb crystals in plasma processing reactors

    E-Print Network [OSTI]

    Kushner, Mark

    Self-consistent three-dimensional model of dust particle transport and formation of Coulomb, University of Illinois, Urbana, Illinois 61801 Gregory A. Hebnerb) Sandia National Laboratories, Albuquerque of Illinois, Urbana, Illinois 61801 Received 24 June 2002; accepted 30 August 2002 Dust particle transport

  3. Atmospheric Modelling for Neptune's Methane D/H Ratio - Preliminary Results

    E-Print Network [OSTI]

    Cotton, Daniel V; Bott, Kimberly; Bailey, Jeremy

    2015-01-01

    The ratio of deuterium to hydrogen (D/H ratio) of Solar System bodies is an important clue to their formation histories. Here we fit a Neptunian atmospheric model to Gemini Near Infrared Spectrograph (GNIRS) high spectral resolution observations and determine the D/H ratio in methane absorption in the infrared H-band ($\\sim$ 1.6 {\\mu}m). The model was derived using our radiative transfer software VSTAR (Versatile Software for the Transfer of Atmospheric Radiation) and atmospheric fitting software ATMOF (ATMOspheric Fitting). The methane line list used for this work has only become available in the last few years, enabling a refinement of earlier estimates. We identify a bright region on the planetary disc and find it to correspond to an optically thick lower cloud. Our preliminary determination of CH$_{\\rm 3}$D/CH$_{\\rm 4}$ is 3.0$\\times10^{-4}$, which is in line with the recent determination of Irwin et al. (2014) of 3.0$^{+1.0}_{-0.9}\\sim\\times10^{-4}$, made using the same model parameters and line list but...

  4. A dynamical and kinematical model of the Galactic stellar halo and possible implications for galaxy formation scenarios

    E-Print Network [OSTI]

    J. Sommer-Larsen; T. C. Beers; C. Flynn; R. Wilhelm; P. R. Christensen

    1996-10-23

    We re-analyse the kinematics of the system of blue horizontal branch field (BHBF) stars in the Galactic halo (in particular the outer halo), fitting the kinematics with the model of radial and tangential velocity dispersions in the halo as a function of galactocentric distance r proposed by Sommer-Larsen, Flynn & Christensen (1994), using a much larger sample (almost 700) of BHBF stars. The basic result is that the character of the stellar halo velocity ellipsoid changes markedly from radial anisotropy at the sun to tangential anisotropy in the outer parts of the Galactic halo (r greater than approx 20 kpc). Specifically, the radial component of the stellar halo's velocity ellipsoid decreases fairly rapidly beyond the solar circle, from approx 140 +/- 10 km/s at the sun, to an asymptotic value of 89 +/- 19 km/s at large r. The rapid decrease in the radial velocity dispersion is matched by an increase in the tangential velocity dispersion, with increasing r. Our results may indicate that the Galaxy formed hierarchically (partly or fully) through merging of smaller subsystems - the 'bottom-up' galaxy formation scenario, which for quite a while has been favoured by most theorists and recently also has been given some observational credibility by HST observations of a potential group of small galaxies, at high redshift, possibly in the process of merging to a larger galaxy (Pascarelle et al 1996).

  5. Gearbox Reliability Collaborative Phase 1 and 2: Testing and Modeling Results; Preprint

    SciTech Connect (OSTI)

    Keller, J.; Guo, Y.; LaCava, W.; Link, H.; McNiff, B.

    2012-05-01

    The Gearbox Reliability Collaborative (GRC) investigates root causes of wind turbine gearbox premature failures and validates design assumptions that affect gearbox reliability using a combined testing and modeling approach. Knowledge gained from the testing and modeling of the GRC gearboxes builds an understanding of how the selected loads and events translate into internal responses of three-point mounted gearboxes. This paper presents some testing and modeling results of the GRC research during Phase 1 and 2. Non-torque loads from the rotor including shaft bending and thrust, traditionally assumed to be uncoupled with gearbox, affect gear and bearing loads and resulting gearbox responses. Bearing clearance increases bearing loads and causes cyclic loading, which could contribute to a reduced bearing life. Including flexibilities of key drivetrain subcomponents is important in order to reproduce the measured gearbox response during the tests using modeling approaches.

  6. A Model For the Formation of High Density Clumps in Proto-Planetary Nebulae

    E-Print Network [OSTI]

    Patrick A. Young; J. L. Highberger; David Arnett; L. M. Ziurys

    2003-09-19

    The detection of NaCl at large radii in the Egg Nebula, CRL 2688, requires densities of 10^7 - 10^8 cm^-3 in a thick shell of r ~ a few X 10^17 cm. To explain these results, a mechanism is needed for producing high densities at a considerable distance from the central star. In two dimensional simulations of the interaction of the fast wind with an ambient medium, the material becomes thermally unstable. The resulting clumps can achieve the requisite conditions for NaCl excitation. We present 2D models with simple physics as proof-of-principle calculations to show that the clumping behavior is robust. Clumping is a natural outcome of cooling in the colliding wind model and comparable to that inferred from observations.

  7. Results from baseline tests of the SPRE I and comparison with code model predictions

    SciTech Connect (OSTI)

    Cairelli, J.E.; Geng, S.M.; Skupinski, R.C.

    1994-09-01

    The Space Power Research Engine (SPRE), a free-piston Stirling engine with linear alternator, is being tested at the NASA Lewis Research Center as part of the Civil Space Technology Initiative (CSTI) as a candidate for high capacity space power. This paper presents results of base-line engine tests at design and off-design operating conditions. The test results are compared with code model predictions.

  8. Numerical model for vibration damping resulting from the first-order phase transformations

    E-Print Network [OSTI]

    Melnik, Roderick

    : Martensite transformation; Thermo-mechanical coupling; Vibration damping; Ginzburg­Landau theory 1Numerical model for vibration damping resulting from the first-order phase transformations L Landau­Ginzburg theory that couples nonlinear mechanical and thermal fields. The free energy function

  9. Modeling and simulation results on a new Compton scattering tomography modality

    E-Print Network [OSTI]

    Nguyen-Verger, Maï K.

    (X-ray scanner, Single Photon Emission Computed Tomography, Positron Emission Tomography, etcModeling and simulation results on a new Compton scattering tomography modality Gaël Rigaud a Biomedical imaging Compton scattering tomography Image reconstruction a b s t r a c t Conventional tomography

  10. TURBULENT COMBUSTION MODELING OF COAL:BIOMASS BLENDS IN A SWIRL BURNER I -PRELIMINARY RESULTS

    E-Print Network [OSTI]

    Daripa, Prabir

    coal or by ex- haust clean up technology. For the power plants, the simplest solution is the preventive- ity well into the 21st century. This dependency on coal calls for better technologies to reduceTURBULENT COMBUSTION MODELING OF COAL:BIOMASS BLENDS IN A SWIRL BURNER I - PRELIMINARY RESULTS

  11. Plasma wave measurements with STEREO S/WAVES: Calibration, potential model, and preliminary results

    E-Print Network [OSTI]

    California at Berkeley, University of

    Plasma wave measurements with STEREO S/WAVES: Calibration, potential model, and preliminary results] The S/WAVES experiments on the two STEREO spacecraft measure waves, both in situ plasma waves and remotely generated waves such as Type II and Type III solar bursts. A part of the experiment is aimed

  12. Albendazole inhibits endothelial cell migration, tube formation, vasopermeability, VEGF receptor-2 expression and suppresses retinal neovascularization in ROP model of angiogenesis

    SciTech Connect (OSTI)

    Pourgholami, Mohammad H.; Khachigian, Levon M.; Fahmy, Roger G.; Badar, Samina; Wang, Lisa; Chu, Stephanie Wai Ling; Morris, David Lawson

    2010-07-09

    The angiogenic process begins with the cell proliferation and migration into the primary vascular network, and leads to vascularization of previously avascular tissues and organs as well to growth and remodeling of the initially homogeneous capillary plexus to form a new microcirculation. Additionally, an increase in microvascular permeability is a crucial step in angiogenesis. Vascular endothelial growth factor (VEGF) plays a central role in angiogenesis. We have previously reported that albendazole suppresses VEGF levels and inhibits malignant ascites formation, suggesting a possible effect on angiogenesis. This study was therefore designed to investigate the antiangiogenic effect of albendazole in non-cancerous models of angiogenesis. In vitro, treatment of human umbilical vein endothelial cells (HUVECs) with albendazole led to inhibition of tube formation, migration, permeability and down-regulation of the VEGF type 2 receptor (VEGFR-2). In vivo albendazole profoundly inhibited hyperoxia-induced retinal angiogenesis in mice. These results provide new insights into the antiangiogenic effects of albendazole.

  13. Comparing Simulation Results with Traditional PRA Model on a Boiling Water Reactor Station Blackout Case Study

    SciTech Connect (OSTI)

    Zhegang Ma; Diego Mandelli; Curtis Smith

    2011-07-01

    A previous study used RELAP and RAVEN to conduct a boiling water reactor station black-out (SBO) case study in a simulation based environment to show the capabilities of the risk-informed safety margin characterization methodology. This report compares the RELAP/RAVEN simulation results with traditional PRA model results. The RELAP/RAVEN simulation run results were reviewed for their input parameters and output results. The input parameters for each simulation run include various timing information such as diesel generator or offsite power recovery time, Safety Relief Valve stuck open time, High Pressure Core Injection or Reactor Core Isolation Cooling fail to run time, extended core cooling operation time, depressurization delay time, and firewater injection time. The output results include the maximum fuel clad temperature, the outcome, and the simulation end time. A traditional SBO PRA model in this report contains four event trees that are linked together with the transferring feature in SAPHIRE software. Unlike the usual Level 1 PRA quantification process in which only core damage sequences are quantified, this report quantifies all SBO sequences, whether they are core damage sequences or success (i.e., non core damage) sequences, in order to provide a full comparison with the simulation results. Three different approaches were used to solve event tree top events and quantify the SBO sequences: “W” process flag, default process flag without proper adjustment, and default process flag with adjustment to account for the success branch probabilities. Without post-processing, the first two approaches yield incorrect results with a total conditional probability greater than 1.0. The last approach accounts for the success branch probabilities and provides correct conditional sequence probabilities that are to be used for comparison. To better compare the results from the PRA model and the simulation runs, a simplified SBO event tree was developed with only four top events and eighteen SBO sequences (versus fifty-four SBO sequences in the original SBO model). The estimated SBO sequence conditional probabilities from the original SBO model were integrated to the corresponding sequences in the simplified SBO event tree. These results were then compared with the simulation run results.

  14. Forward Modeling of the Induction Log Response of a Fractured Geologic Formation 

    E-Print Network [OSTI]

    Bray, Steven Hunter

    2013-05-02

    is a very powerful tool that provides valuable information to industry and researchers. Any way to further develop this proven method is beneficial. Whether it is characterizing hydro-fracking jobs or evaluating formations in exploration...

  15. Response of a laminar premixed flame to flow oscillations: A kinematic model and thermoacoustic instability results

    SciTech Connect (OSTI)

    Fleifil, M.; Annaswamy, A.M.; Ghoneim, A.F.; Ghoneim, Z.A.

    1996-09-01

    Combustion instability is a resonance phenomenon that arises due to the coupling between the system acoustics and the unsteady heat release. The constructive feedback between the two processes, which is known to occur as a certain phase relationship between the pressure and the unsteady heat release rate is satisfied, depends on many parameters among which is the acoustic mode, the flame holder characteristics, and the dominant burning pattern. In this paper, the authors construct an analytical model to describe the dynamic response of a laminar premixed flame stabilized on the rim of a tube to velocity oscillation. They consider uniform and nonuniform velocity perturbations superimposed on a pipe flow velocity profile. The model results show that the magnitude of heat release perturbation and its phase with respect to the dynamic perturbation dependent primarily on the flame Strohal number, representing the ratio of the dominant frequency times the tube radius to the laminar burning velocity. In terms of this number, high-frequency perturbations pass through the flame while low frequencies lead to a strong response. The phase with respect to the velocity perturbation behaves in the opposite way. Results of this model are shown to agree with experimental observations and to be useful in determining how the combustion excited model is selected among all the acoustic unstable modes. The model is then used to obtain a time-domain differential equation describing the relationship between the velocity perturbation and the heat release response over the entire frequency range.

  16. Solar Deployment System (SolarDS) Model: Documentation and Sample Results

    SciTech Connect (OSTI)

    Denholm, P.; Drury, E.; Margolis, R.

    2009-09-01

    The Solar Deployment System (SolarDS) model is a bottom-up, market penetration model that simulates the potential adoption of photovoltaics (PV) on residential and commercial rooftops in the continental United States through 2030. NREL developed SolarDS to examine the market competitiveness of PV based on regional solar resources, capital costs, electricity prices, utility rate structures, and federal and local incentives. The model uses the projected financial performance of PV systems to simulate PV adoption for building types and regions then aggregates adoption to state and national levels. The main components of SolarDS include a PV performance simulator, a PV annual revenue calculator, a PV financial performance calculator, a PV market share calculator, and a regional aggregator. The model simulates a variety of installed PV capacity for a range of user-specified input parameters. PV market penetration levels from 15 to 193 GW by 2030 were simulated in preliminary model runs. SolarDS results are primarily driven by three model assumptions: (1) future PV cost reductions, (2) the maximum PV market share assumed for systems with given financial performance, and (3) PV financing parameters and policy-driven assumptions, such as the possible future cost of carbon emissions.

  17. Multi-epoch very long baseline interferometric observations of the nuclear starburst region of NGC 253: Improved modeling of the supernova and star formation rates

    SciTech Connect (OSTI)

    Rampadarath, H.; Morgan, J. S.; Tingay, S. J.; Lenc, E.

    2014-01-01

    The results of multi-epoch observations of the southern starburst galaxy, NGC 253, with the Australian Long Baseline Array at 2.3 GHz are presented. As with previous radio interferometric observations of this galaxy, no new sources were discovered. By combining the results of this survey with Very Large Array observations at higher frequencies from the literature, spectra were derived and a free-free absorption model was fitted of 20 known sources in NGC 253. The results were found to be consistent with previous studies. The supernova remnant, 5.48-43.3, was imaged with the highest sensitivity and resolution to date, revealing a two-lobed morphology. Comparisons with previous observations of similar resolution give an upper limit of 10{sup 4} km s{sup –1} for the expansion speed of this remnant. We derive a supernova rate of <0.2 yr{sup –1} for the inner 300 pc using a model that improves on previous methods by incorporating an improved radio supernova peak luminosity distribution and by making use of multi-wavelength radio data spanning 21 yr. A star formation rate of SFR(M ? 5 M {sub ?}) < 4.9 M {sub ?} yr{sup –1} was also estimated using the standard relation between supernova and star formation rates. Our improved estimates of supernova and star formation rates are consistent with studies at other wavelengths. The results of our study point to the possible existence of a small population of undetected supernova remnants, suggesting a low rate of radio supernova production in NGC 253.

  18. Three-Dimensional Thermal-Electrochemical Coupled Model for Spirally Wound Large-Format Lithium-Ion Batteries (Presentation)

    SciTech Connect (OSTI)

    Lee, K. J.; Smith K.; Kim, G. H.

    2011-04-01

    This presentation discusses the behavior of spirally wound large-format Li-ion batteries with respect to their design. The objectives of the study include developing thermal and electrochemical models resolving 3-dimensional spirally wound structures of cylindrical cells, understanding the mechanisms and interactions between local electrochemical reactions and macroscopic heat and electron transfers, and developing a tool and methodology to support macroscopic designs of cylindrical Li-ion battery cells.

  19. Numerical Modeling of AGN Jets: Formation of Magnetically Dominated Lobes and Stability Properties of Current-carrying Jets

    E-Print Network [OSTI]

    Masanori Nakamura; Hui Li; Steven Diehl; Shengtai Li

    2007-07-10

    We argue the behavior of Poynting flux-dominated outflows from AGN in the galactic cluster systems by performing three-dimensional MHD simulations within the framework of the "magnetic tower" model. Of particular interests are the structure of MHD waves, the cylindrical radial force balance, the (de)collimation, and the stability properties of magnetic tower jets. Transition between the jet/lobe and the formation of wiggling jet by growing current-driven instability are discussed.

  20. Results on the search for the standard model Higgs boson at CMS

    SciTech Connect (OSTI)

    Fabozzi, Francesco [INFN Sezione di Napoli, Complesso Univ. di Monte S. Angelo Via Cintia - 80126 Napoli (Italy) and Universita della Basilicata, Viale dell'Ateneo Lucano 10 - 85100 Potenza (Italy); Collaboration: CMS Collaboration

    2012-10-23

    A summary of the results from searches for the Standard Model Higgs Boson in the CMS experiment at LHC with data collected from proton-proton collisions at {radical}(s) = 7TeV is presented. The Higgs boson is searched in a multiplicity of decay channels using data samples corresponding to integrated luminosities in the range 4.6 - 4.8 fb{sup -1}. The investigated mass range is 110 - 600 GeV. Results are reported for each channel as well as for their combination.

  1. Self-consistent quasiparticle model results for ultrarelativistic electron-positron thermodynamic plasma

    SciTech Connect (OSTI)

    Bannur, Vishnu M. [Department of Physics, University of Calicut, Kerala-673 635 (India)

    2006-06-15

    Relativistic plasma with two charge species and radiation at thermodynamic equilibrium is a general system of interest in astrophysics and high-energy physics. We develop a self-consistent quasiparticle model for such a system to take account of the collective behavior of plasma, and thermodynamic properties are derived. It is applied to the ultrarelativistic electron-positron plasma and compared with previous results.

  2. Recent results on the nonmesonic weak decay of hypernuclei within a one-meson-exchange model

    E-Print Network [OSTI]

    A. Parreno; A. Ramos; C. Bennhold

    2001-09-06

    We update our previous results for the nonmesonic decay of $^{12}_\\Lambda$C and $^5_\\Lambda$He. We pay special attention to the role played by Final State Intreractions on the decay observables. We follow a One-Meson-Exchange model which includes the exchange of the $\\pi, \\rho, K, K^*, \\eta$ and $\\omega$ mesons. We also present recent predictions for different observables concerning the decay of the doubly strange $^6_{\\Lambda \\Lambda}$He hypernucleus.

  3. COMPARISON OF EXPERIMENTAL RESULTS TO CFD MODELS FOR BLENDING IN A TANK USING DUAL OPPOSING JETS

    SciTech Connect (OSTI)

    Leishear, R.

    2011-08-07

    Research has been completed in a pilot scale, eight foot diameter tank to investigate blending, using a pump with dual opposing jets. The jets re-circulate fluids in the tank to promote blending when fluids are added to the tank. Different jet diameters and different horizontal and vertical orientations of the jets were investigated. In all, eighty five tests were performed both in a tank without internal obstructions and a tank with vertical obstructions similar to a tube bank in a heat exchanger. These obstructions provided scale models of several miles of two inch diameter, serpentine, vertical cooling coils below the liquid surface for a full scale, 1.3 million gallon, liquid radioactive waste storage tank. Two types of tests were performed. One type of test used a tracer fluid, which was homogeneously blended into solution. Data were statistically evaluated to determine blending times for solutions of different density and viscosity, and the blending times were successfully compared to computational fluid dynamics (CFD) models. The other type of test blended solutions of different viscosity. For example, in one test a half tank of water was added to a half tank of a more viscous, concentrated salt solution. In this case, the fluid mechanics of the blending process was noted to significantly change due to stratification of fluids. CFD models for stratification were not investigated. This paper is the fourth in a series of papers resulting from this research (Leishear, et.al. [1- 4]), and this paper documents final test results, statistical analysis of the data, a comparison of experimental results to CFD models, and scale-up of the results to a full scale tank.

  4. The model problem Idea of the proof of the main results On stabilization of small solutions in the nonlinear

    E-Print Network [OSTI]

    Thomann, Laurent

    The model problem Idea of the proof of the main results On stabilization of small solutions work with Scipio Cuccagna (University of Trieste) #12;The model problem Idea of the proof of the main results Outline 1 The model problem The NLD: general setting Further notations Main results The case

  5. Evaluating Impacts of CO2 Intrusion into an Unconsolidated Aquifer: II. Modeling Results

    SciTech Connect (OSTI)

    Zheng, Liange; Qafoku, Nikolla; Lawter, Amanda R.; Wang, Guohui; Shao, Hongbo; Brown, Christopher F.

    2015-08-04

    Large scale deployment of CO2 geological sequestration requires the assessment of the risks. One of the potential risks is the impact of CO2 leakage on shallow groundwater overlying the sequestration site.The understanding of the key chemical processes and parameters are critical for building numerical models for risk assessment. Model interpretation of laboratory and field tests is an effective way to enhance such understanding. Column experiments in which CO2 charged synthetic groundwater flowed through a column packed with material from High Plains aquifer was conducted and concentration of several constituents in the effluent water was analyzed. In this paper, reactive transport model was developed to interpret the observed concentration changes, attempting to shed light on the chemical reactions and key parameters that control the concentration changes of these constituents. The reactive transport model catches the concentration changes of pH, Ca, Mg, Ba, Sr, Cs, As and Pb fairly well. Calcite dissolution and Ca-driven cation exchange reactions are the major drivers for the concentration changes of Ca, Ba, Sr, and Cs. The pH-driven adsorption/desorption reactions lead to a concentration increase of As and Pb. The volume fraction and reactive surface area of calcite, CEC and sorption capacity are key parameters in determining the magnitude of concentration increase. Model results also show that the dissolution of calcite with Ba impurity could be an alternative explanation of the increase in Ba concentration.

  6. Discrete Element Modeling Results of Proppant Rearrangement in the Cooke Conductivity Cell

    SciTech Connect (OSTI)

    Earl Mattson; Hai Huang; Michael Conway; Lisa O'Connell

    2014-02-01

    The study of propped fracture conductivity began in earnest with the development of the Cooke cell which later became part of the initial API standard. Subsequent developments included a patented multicell design to conduct 4 tests in a press at the same time. Other modifications have been used by various investigators. Recent studies by the Stim-Lab proppant consortium have indicated that the flow field across a Cooke proppant conductivity testing cell may not be uniform as initially believed which resulted is significantly different conductivity results. Post test analysis of low temperature metal alloy injections at the termination of proppant testing prior to the release of the applied stress suggest that higher flow is to be expected along the sides and top of the proppant pack than compared to the middle of the pack. To evaluate these experimental findings, a physics-based two-dimensional (2-D) discrete element model (DEM) was developed and applied to simulate proppant rearrangement during stress loading in the Cooke conductivity cell and the resulting porosity field. Analysis of these simulations are critical to understanding the impact of modification to the testing cell as well as understanding key proppant conductivity issues such as how these effects are manifested in proppant concentration testing results. The 2-D DEM model was constructed to represent a realistic cross section of the Cooke cell with a distribution of four material properties, three that represented the Cooke cell (steel, sandstone,square rings), and one representing the proppant. In principle, Cooke cell materials can be approximated as assemblies of independent discrete elements (particles) of various sizes and material properties that interact via cohesive interactions, repulsive forces, and frictional forces. The macroscopic behavior can then be modeled as the collective behavior of many interacting discrete elements. This DEM model is particularly suitable for modeling proppant mechanical interactions subjected to an applied stress, where the experimental cell is represented as a cohesive body composed of a large number of discrete elements, and proppants can be modeled as the individual discrete particles with various sizes (following the proppant size distribution-density function used in the test) that exhibit no cohesive strength between the particles. Initial 2-D DEM modeling results suggest that proppant rearrangement and non-uniform stress distribution across the proppant pack results in significant non-uniform porosity distribution across the Cooke cell. Larger porosities develop along the edge of the proppant pack beneath the square ring seal and would result in a disproportionate higher flow field along these edges as compared to the middle of the proppant pack. These results suggest that reported conductivity values determined by the Cooke cell may be biased to overestimate the actual conductivity of the proppant at high stresses and that modifications to the standard Cooke cell will affect the magnitude of this bias.

  7. Modeling of fate and transport of co-injection of H2S with CO2 in deep saline formations

    SciTech Connect (OSTI)

    Zhang, W.; Xu, T.; Li, Y.

    2010-12-15

    The geological storage of CO{sub 2} in deep saline formations is increasing seen as a viable strategy to reduce the release of greenhouse gases into the atmosphere. However, costs of capture and compression of CO{sub 2} from industrial waste streams containing small quantities of sulfur and nitrogen compounds such as SO{sub 2}, H{sub 2}S and N{sub 2} are very expensive. Therefore, studies on the co-injection of CO{sub 2} containing other acid gases from industrial emissions are very important. In this paper, numerical simulations were performed to study the co-injection of H{sub 2}S with CO{sub 2} in sandstone and carbonate formations. Results indicate that the preferential dissolution of H{sub 2}S gas (compared with CO{sub 2} gas) into formation water results in the delayed breakthrough of H{sub 2}S gas. Co-injection of H{sub 2}S results in the precipitation of pyrite through interactions between the dissolved H{sub 2}S and Fe{sup 2+} from the dissolution of Fe-bearing minerals. Additional injection of H{sub 2}S reduces the capabilities for solubility and mineral trappings of CO{sub 2} compared to the CO{sub 2} only case. In comparison to the sandstone (siliciclastic) formation, the carbonate formation is less favorable to the mineral sequestration of CO{sub 2}. Different from CO{sub 2} mineral trapping, the presence of Fe-bearing siliciclastic and/or carbonate is more favorable to the H{sub 2}S mineral trapping.

  8. Reservoir Characterization and Modeling of the Glorieta and the Clearfork Formations, Monahans Field, Permian Basin, Texas 

    E-Print Network [OSTI]

    Yeatman, Ryan Yeatman

    2012-10-19

    facies model, porosity model, and a siltstone model were generated in Petrel to better characterize the Monahans Field reservoir. Interbedded impermeable siltstone beds in Monahans Field partition the reservoir making oil production and water injection...

  9. Model of calcareous deposit formation on cathodically protected steel in seawater: improvements and extensions 

    E-Print Network [OSTI]

    Blackburne, Patricia Nicole

    1996-01-01

    A mathematical model of calcareous deposits on cathodically protected steel in seawater has been improved for practical applications. The model can be used in industry and as a pedagogical tool. The model extracts useful information from National...

  10. Thermodynamics of the O(3) model in 1+1 dimensions: lattice vs. analytical results

    E-Print Network [OSTI]

    Elina Seel; Dominik Smith; Stefano Lottini; Francesco Giacosa

    2013-07-01

    A detailed study of the thermodynamics of the O(N=3) model in 1+1 dimensions is presented, employing a two-particle-irreducible resummation prescription as well as fully nonperturbative finite-temperature lattice simulations. The analytical results are computed using the Cornwall-Jackiw-Tomboulis (CJT) formalism and the auxiliary field method to one- and to two-loop order. The lattice results are obtained through Monte Carlo simulation for various lattice spacings. The analytical and lattice results for pressure, trace anomaly, and energy density, resembling closely those of four-dimensional Yang-Mills theories, are compared with each other. We find that to one-loop order there is a good correspondence between the CJT formalism and the lattice study for low temperatures. However, at high T the two-loop calculation fares better, correcting for the overestimation from the former approximation.

  11. PREDICTION OF DEFORMATION AND HOT TEAR FORMATION USING A VISCOPLASTIC MODEL WITH DAMAGE

    E-Print Network [OSTI]

    Beckermann, Christoph

    strains due to the contraction of the casting and geometric constraints of the mold. In the mushy zone considering material damage is used to predict hot tear formation in a permanent mold magnesium alloy casting sprue. The hot tearing severity is manipulated by adjusting the initial mold temperature. The simulation

  12. Results of an emergency response atmospheric dispersion model comparison using a state accepted statistical protocol

    SciTech Connect (OSTI)

    Ciolek, J.T. Jr.

    1993-10-01

    The Rocky Flats Plant, located approximately 26 km northwest of downtown Denver, Colorado, has developed an emergency response atmospheric dispersion model for complex terrain applications. Plant personnel would use the model, known as the Terrain-Responsive Atmospheric Code (TRAC) (Hodgin 1985) to project plume impacts and provide off-site protective action recommendations to the State of Colorado should a hazardous material release occur from the facility. The Colorado Department of Health (CDH) entered into an interagency agreement with the Rocky Flats Plant prime contractor, EG&G Rocky Flats, and the US Department of Energy to evaluate TRAC as an acceptable emergency response tool. After exhaustive research of similar evaluation processes from other emergency response and regulatory organizations, the interagency committee devised a formal acceptance process. The process contains an evaluation protocol (Hodgin and Smith 1992), descriptions of responsibilities, an identified experimental data set to use in the evaluation, and judgment criteria for model acceptance. The evaluation protocol is general enough to allow for different implementations. This paper explains one implementation, shows protocol results for a test case, and presents results of a comparison between versions of TRAC with different wind Field codes: a two dimensional mass consistent code called WINDS (Fosberg et al. 1976) that has been extended to three dimensions, and a fully 3 dimensional mass conserving code called NUATMOS (Ross and Smith 1987, Ross et al. 1988).

  13. A Comparison of Shell Model Results for Some properties of the Even-Even Ge Isotopes

    E-Print Network [OSTI]

    S. J. Q. Robinson; L. Zamick; Y. Y. Sharon

    2010-07-13

    In this work we examine two recent effective shell model interactions, JUN45 and JJ4B, that have been proposed for use in the $f_{5/2},p_{3/2}, p_{1/2}, g_{9/2}$ model space for both protons and neutrons. We calculate a number of quantities that did not enter into the fits undertaken to fix the parameters of both interactions. In particular we consider static quadrupole moments (Q's) of excited states of the even-even $^{70-76}$Ge isotopes, as well as the B(E2) values in these nuclei. (We have previously studied $^{70}$Zn isotopes using JJ4B.) Some striking disagreements between the JUN45 prediction and the experimental results had already been noted for the quadrupole moments of the $2_1^+$ states of these nuclei. We investigate whether these discrepancies also occur for the JJ4B interaction. Subsequently, we also apply both interactions to calculate the Q's of some more highly excited states and compare the two sets of predictions regarding the nature of the nuclear states under consideration. In order to gain insight into these more complex large-scale shell-model calculations, we examine the corresponding and much simpler single-j shell model calculations in the $g_{9/2}$ neutron shell.

  14. Measurements and modeling of HO2 formation in the reactions of n-C3H7 and i-C3H7 radicals with O2.

    SciTech Connect (OSTI)

    Taatjes, Craig A.; Estupinan, Edgar Garcia; Klippenstein, Stephen J.

    2004-08-01

    The formation of HO{sub 2} in the reactions of C{sub 2}H{sub 5}, n-C{sub 3}H{sub 7}, and i-C{sub 3}H{sub 7} radicals with O{sub 2} is investigated using the technique of laser photolysis/long-path frequency-modulation spectroscopy. The alkyl radicals are formed by 266 nm photolysis of alkyl iodides. The formation of HO{sub 2} from the subsequent reaction of the alkyl radicals with O{sub 2} is followed by infrared frequency-modulation spectroscopy. The concentration of I atoms is simultaneously monitored by direct absorption of a second laser probe on the spin?orbit transition. The measured profiles are compared to a kinetic model taken from time-resolved master-equation results based on previously published ab initio characterizations of the relevant stationary points on the potential-energy surface. The ab initio energies are adjusted to produce agreement with the present experimental data and with available literature studies. The isomer specificity of the present results enables refinement of the model for i-C{sub 3}H{sub 7} + O{sub 2} and improved agreement with experimental measurements of HO{sub 2} production in propane oxidation.

  15. Lattice model for self-assembly with application to the formation of cytoskeletal-like structures Shannon F. Stewman and Aaron R. Dinner*

    E-Print Network [OSTI]

    Dinner, Aaron

    Lattice model for self-assembly with application to the formation of cytoskeletal-like structures for Biophysical Dynamics, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, USA Received. By enabling the de novo formation of coexisting morphologies without the computational cost of explicit

  16. New Model to Predict Formation Damage due to Sulfur Deposition in Sour M.A. Mahmoud and A.A. Al-Majed, KFUPM, all SPE

    E-Print Network [OSTI]

    Al-Majed, Abdulaziz Abdullah

    SPE 149535 New Model to Predict Formation Damage due to Sulfur Deposition in Sour Gas Wells M of SPE copyright. Abstract Elemental sulfur (S8) is often present in considerable amounts in sour gas to deposit in the formation. Sulfur deposition can cause severe loss in the pore space available for gas

  17. Dynamic soil-structure interaction-comparison of FEM model with experimental results 

    E-Print Network [OSTI]

    Srinivasan, Palanivel Rajan

    2000-01-01

    Linearly elastic finite element models are developed for particular scale-model gravity retaining wall structures. The sand is modeled as a homogenous isotropic linearly elastic continuum. Models are created in four different configurations...

  18. Results from Alloy 600 And Alloy 690 Caustic SCC Model Boiler Tests

    SciTech Connect (OSTI)

    Miller, Frederick D.; Thomas, Larry E.

    2009-08-03

    A versatile model boiler test methodology was developed and used to compare caustic stress corrosion cracking (SCC) of mill annealed Alloy 600 and thermally treated Alloy 690. The model boiler included simulated crevice devices that efficiently and consistently concentrated Na2CO3, resulting in volatilization of CO2 with the steam and concentration of NaOH at the tube surfaces. The test methodology also included variation in tube stress, either produced by the primary to secondary side pressure differential, or by a novel method that reproducibly yields a higher stress condition on the tube. The significant effect of residual stress on tube SCC was also considered. SCC of both Alloy 600 and Alloy 690 were evaluated as a function of temperature and stress. Analytical transmission electron microscopy (ATEM) evaluations of the cracks and the grain boundaries ahead of the cracks were performed, providing insight into the SCC mechanism. This model boiler test methodology may be applicable to a range of bulkwater secondary chemistries that concentrate to produce aggressive crevice environments.

  19. Hawaii Solar Integration Study: Solar Modeling Developments and Study Results; Preprint

    SciTech Connect (OSTI)

    Orwig, K.; Corbus, D.; Piwko, R.; Schuerger, M.; Matsuura, M.; Roose, L.

    2012-12-01

    The Hawaii Solar Integration Study (HSIS) is a follow-up to the Oahu Wind Integration and Transmission Study completed in 2010. HSIS focuses on the impacts of higher penetrations of solar energy on the electrical grid and on other generation. HSIS goes beyond the island of Oahu and investigates Maui as well. The study examines reserve strategies, impacts on thermal unit commitment and dispatch, utilization of energy storage, renewable energy curtailment, and other aspects of grid reliability and operation. For the study, high-frequency (2-second) solar power profiles were generated using a new combined Numerical Weather Prediction model/ stochastic-kinematic cloud model approach, which represents the 'sharp-edge' effects of clouds passing over solar facilities. As part of the validation process, the solar data was evaluated using a variety of analysis techniques including wavelets, power spectral densities, ramp distributions, extreme values, and cross correlations. This paper provides an overview of the study objectives, results of the solar profile validation, and study results.

  20. Interpreting the Global 21-cm Signal from High Redshifts. II. Parameter Estimation for Models of Galaxy Formation

    E-Print Network [OSTI]

    Mirocha, Jordan; Burns, Jack O

    2015-01-01

    Following our previous work, which related generic features in the sky-averaged (global) 21-cm signal to properties of the intergalactic medium, we now investigate the prospects for constraining a simple galaxy formation model with current and near-future experiments. Markov-Chain Monte Carlo fits to our synthetic dataset, which includes a realistic galactic foreground, a plausible model for the signal, and noise consistent with 100 hours of integration by an ideal instrument, suggest that a simple four-parameter model that links the production rate of Lyman-$\\alpha$, Lyman-continuum, and X-ray photons to the growth rate of dark matter halos can be well-constrained (to $\\sim 0.1$ dex in each dimension) so long as all three spectral features expected to occur between $40 \\lesssim \

  1. MODELLING SURFACE HOAR FORMATION AND EVOLUTION ON MOUNTAIN SLOPES Simon Horton1

    E-Print Network [OSTI]

    Jamieson, Bruce

    evaluates surface hoar size predictions made with empirical weather based models and discusses how buried. Weather station data and forecasted data from the GEM15 numerical weather prediction model were used. The surface energy balance model made good predictions of crystal size with real station data (r2 = 0

  2. SIMULATION MODEL ANALYSIS OF THE MOST PROMISING GEOLOGIC SEQUESTRATION FORMATION CANDIDATES IN THE ROCKY MOUNTAIN REGION, USA, WITH FOCUS ON UNCERTAINTY ASSESSMENT

    SciTech Connect (OSTI)

    Lee, Si-Yong; Zaluski, Wade; Will, Robert; Eisinger, Chris; Matthews, Vince; McPherson, Brian

    2013-09-01

    The purpose of this report is to report results of reservoir model simulation analyses for forecasting subsurface CO2 storage capacity estimation for the most promising formations in the Rocky Mountain region of the USA. A particular emphasis of this project was to assess uncertainty of the simulation-based forecasts. Results illustrate how local-scale data, including well information, number of wells, and location of wells, affect storage capacity estimates and what degree of well density (number of wells over a fixed area) may be required to estimate capacity within a specified degree of confidence. A major outcome of this work was development of a new workflow of simulation analysis, accommodating the addition of “random pseudo wells” to represent virtual characterization wells.

  3. Ice formation on nitric acid coated dust particles: Laboratory and modeling studies

    SciTech Connect (OSTI)

    Kulkarni, Gourihar R.; Zhang, Kai; Zhao, Chun; Nandasiri, Manjula I.; Shutthanandan, V.; Liu, Xiaohong; Fast, Jerome D.; Berg, Larry K.

    2015-08-16

    Changes in the ice nucleation characteristics of atmospherically relevant mineral dust particles due to nitric acid coating are not well understood. Further, the atmospheric implications of dust coating on ice-cloud properties under different assumptions of primary ice nucleation mechanisms are unknown. We investigated ice nucleation ability of Arizona test dust, illite, K-feldspar and quartz as a function of temperature (-25 to -30°C) and relative humidity with respect to water (75 to 110%). Particles were size selected at 250 nm and transported (bare or coated) to the ice nucleation chamber to determine the fraction of particles nucleating ice at various temperature and water saturation conditions. All dust nucleated ice at water-subsaturated conditions, but the coated particles showed a reduction in their ice nucleation ability compared to bare particles. However, at water-supersaturated conditions, we observed that bare and coated particles had nearly similar ice nucleation characteristics. X-ray diffraction patterns indicated that structural properties of bare dust particles modified after acid treatment. We found that lattice parameters were slightly different, but crystallite sizes of the coated particles were reduced compared to bare particles. Next, single-column model results show that simulated ice crystal number concentrations mostly depends upon fraction of particles that are coated, primary ice nucleation mechanisms, and the competition between ice nucleation mechanisms to nucleate ice. In general, we observed that coating modify the ice-cloud properties and the picture of ice and mixed-phase cloud evolution is complex when different primary ice nucleation mechanisms are competing for fixed water vapor mass.

  4. The MIT Emissions Prediction and Policy Analysis (EPPA) model : revisions, sensitivities, and comparisons of results

    E-Print Network [OSTI]

    Babiker, Mustafa H.M.; Reilly, John M.; Mayer, Monika.; Eckaus, Richard S.; Sue Wing, Ian.; Hyman, Robert C.

    The Emissions Prediction and Policy Analysis (EPPA) model is a component of the MIT Integrated Earth Systems Model (IGSM). Here, we provide an overview of the model accessible to a broad audience and present the detailed ...

  5. Using Pre-Modeled Scenarios to Estimate Groundwater VOC Concentrations Resulting from Vadose Zone Sources

    SciTech Connect (OSTI)

    Oostrom, Martinus; Truex, Michael J.; Rice, Amy K.; Johnson, Christian D.; Carroll, Kenneth C.; Becker, Dave; Simon, Michelle A.

    2014-04-28

    Soil vapor extraction (SVE) is a prevalent remediation approach for volatile contaminants in the vadose zone. To support selection of an appropriate endpoint for the SVE remedy, an evaluation is needed to determine whether vadose zone contamination has been diminished sufficiently to protect groundwater. When vapor-phase transport is an important component of the overall contaminant fate and transport from a vadose zone source, the contaminant concentration expected in groundwater is controlled by a limited set of parameters, including specific site dimensions, vadose zone properties, and source characteristics. An approach was developed for estimating the contaminant concentration in groundwater resulting from a contaminant source in the vadose zone based on pre-modeling contaminant transport for a matrix of parameter value combinations covering a range of potential site conditions. An interpolation and scaling process are then applied to estimate groundwater impact for site-specific conditions.

  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. Universality conjecture and results for a model of several coupled positive-definite matrices

    E-Print Network [OSTI]

    Marco Bertola; Thomas Bothner

    2015-02-01

    The paper contains two main parts: in the first part, we analyze the general case of $p\\geq 2$ matrices coupled in a chain subject to Cauchy interaction. Similarly to the Itzykson-Zuber interaction model, the eigenvalues of the Cauchy chain form a multi level determinantal point process. We first compute all correlations functions in terms of Cauchy biorthogonal polynomials and locate them as specific entries of a $(p+1)\\times (p+1)$ matrix valued solution of a Riemann-Hilbert problem. In the second part, we fix the external potentials as classical Laguerre weights. We then derive strong asymptotics for the Cauchy biorthogonal polynomials when the support of the equilibrium measures contains the origin. As a result, we obtain a new family of universality classes for multi-level random determinantal point fields which include the Bessel$_\

  8. The Role of Asia in Mitigating Climate Change: Results from the Asia Modeling Exercise

    SciTech Connect (OSTI)

    Calvin, Katherine V.; Clarke, Leon E.; Krey, Volker; Blanford, Geoffrey J.; Jiang, Kejun; Kainuma, M.; Kriegler, Elmar; Luderer, Gunnar; Shukla, Priyadarshi R.

    2012-12-01

    In 2010, Asia accounted for 60% of global population, 39% of Gross World Product, 44% of global energy consumption and nearly half of the world’s energy system CO2 emissions. Thus, Asia is an important region to consider in any discussion of climate change or climate change mitigation. This paper explores the role of Asia in mitigating climate change, by comparing the results of 23 energy-economy and integrated assessment models. We focus our analysis on seven key areas: base year data, future energy use and emissions absent climate policy, the effect of urban and rural development on future energy use and emissions, the role of technology in emissions mitigation, regional emissions mitigation, and national climate policies

  9. NUMERICAL MODELING FOR THE FORMATION MECHANISM OF 3D TOPOGRAPHY ON MICROBIAL MAT SURFACES 

    E-Print Network [OSTI]

    Patel, Harsh Jay

    2013-09-27

    a node in the fluid to solid (aggregate or the particle) ? b number of discrete velocities 14 In order to stochastically solve the stochastic solute diffusion equation (Eq. 6), initial and boundary conditions are specified before solving...) Model........................................... 1.2.2 The Diffusion Limited Aggregation-Cellular Automata (DLA-CA) Model................................................................................................ 1.2.3 The Reaction-Diffusion...

  10. Thermo-solutal modelling of microstructure formation during multiphase alloy solidification

    E-Print Network [OSTI]

    Jimack, Peter

    -equilibrium thermodynamics Abstract. This paper shows how to move from a specification of free energy for the solidification for single-phase thermal-solutal models, which contains generalisations and extra terms which challenge standard models. We also present, for the first time, the temperature equation for thermal multi

  11. PHYSICAL REVIEW E 85, 041136 (2012) Jamming and pattern formation in models of segregation

    E-Print Network [OSTI]

    McKane, Alan

    2012-01-01

    2012; published 24 April 2012) We investigate the Schelling model of social segregation, formulated to be derived. Analysis of these equations reveals a jamming transition in the regime of low-vacancy density Schelling proposed a simple model of social segregation in which agents of two different types are placed

  12. Methyl Formate Oxidation: Speciation Data, Laminar Burning Velocities, Ignition Delay Times and a Validated Chemical Kinetic Model

    SciTech Connect (OSTI)

    Dooley, S.; Burke, M. P.; Chaos, M.; Stein, Y.; Dryer, F. L.; Zhukov, V. P.; Finch, O.; Simmie, J. M.; Curran, H. J.

    2010-07-16

    The oxidation of methyl formate (CH{sub 3}OCHO) has been studied in three experimental environments over a range of applied combustion relevant conditions: 1. A variable-pressure flow reactor has been used to quantify reactant, major intermediate and product species as a function of residence time at 3 atm and 0.5% fuel concentration for oxygen/fuel stoichiometries of 0.5, 1.0, and 1.5 at 900 K, and for pyrolysis at 975 K. 2. Shock tube ignition delays have been determined for CH{sub 3}OCHO/O{sub 2}/Ar mixtures at pressures of ? 2.7, 5.4, and 9.2 atm and temperatures of 1275–1935 K for mixture compositions of 0.5% fuel (at equivalence ratios of 1.0, 2.0, and 0.5) and 2.5% fuel (at an equivalence ratio of 1.0). 3. Laminar burning velocities of outwardly propagating spherical CH{sub 3}OCHO/air flames have been determined for stoichiometries ranging from 0.8–1.6, at atmospheric pressure using a pressure-release-type high-pressure chamber. A detailed chemical kinetic model has been constructed, validated against, and used to interpret these experimental data. The kinetic model shows that methyl formate oxidation proceeds through concerted elimination reactions, principally forming methanol and carbon monoxide as well as through bimolecular hydrogen abstraction reactions. The relative importance of elimination versus abstraction was found to depend on the particular environment. In general, methyl formate is consumed exclusively through molecular decomposition in shock tube environments, while at flow reactor and freely propagating premixed flame conditions, there is significant competition between hydrogen abstraction and concerted elimination channels. It is suspected that in diffusion flame configurations the elimination channels contribute more significantly than in premixed environments.

  13. Theoretical predictions of experimental observables sensitive to the symmetry energy: Results of the SMF transport model

    E-Print Network [OSTI]

    Maria Colonna; Virgil Baran; Massimo Di Toro

    2013-12-03

    In the framework of mean-field based transport approaches, we discuss recent results concerning heavy ion reactions between charge asymmetric systems, from low up to intermediate energies. We focus on isospin sensitive observables, aiming at extracting information on the density dependence of the isovector part of the nuclear effective interaction and of the nuclear symmetry energy. For reactions close to the Coulomb barrier, we explore the structure of collective dipole oscillations, rather sensitive to the low-density behavior of the symmetry energy. In the Fermi energy regime, we investigate the interplay between dissipation mechanisms, fragmentation and isospin effects. At intermediate energies, where regions with higher density and momentum are reached, we discuss collective flows and their sensitivity to the momentum dependence of the isovector interaction channel, which determines the splitting of neutron and proton effective masses. Finally, we also discuss the isospin effect on the possible phase transition from nucleonic matter to quark matter. Results are critically reviewed, also trying to establish a link, when possible, with the outcome of other transport models.

  14. Modeling crater formation in femtosecond-pulse laser damage from basic principles

    E-Print Network [OSTI]

    Mitchell, Robert A; Chowdhury, Enam A

    2015-01-01

    We present the first fundamental simulation method for the determination of crater morphology due to femtosecond-pulse laser damage. To this end we have adapted the particle-in-cell (PIC) method commonly used in plasma physics for use in the study of laser damage, and developed the first implementation of a pair-potential for PIC codes. We find that the PIC method is a complementary approach to modeling laser damage, bridging the gap between fully ab-initio molecular dynamics approaches and empirical models. We demonstrate our method by modeling a femtosecond-pulse laser incident on a flat copper slab, for a range of intensities.

  15. A comparative study of analytical models to estimate the LNAPL mound formation 

    E-Print Network [OSTI]

    Ahmed, Ashfaq

    1994-01-01

    developed. Even though these models are based on various as- sumptions, they are useful as tools in evaluating the spreading of the free oil phase during sn oil spill. The spreading depends on many factors, such as leak volume, type of petroleum product..., hydrogeological conditions, and hydraulic properties of the medium as well as the oil. Among the various modeling approaches to predict spill migration, the sharp interface approach has been widely examined due to its simplicity for homogeneous media...

  16. Performance of VAV Parallel Fan Powered Terminal Units: Experimental Results and Models 

    E-Print Network [OSTI]

    Furr, J.; O'Neal, D.; Davis, M.; Bryant, J.; Cramlet, A.

    2008-01-01

    to develop empirical models of airflow, power, and leakage of both parallel and series fan power terminal units. These models are suitable for use in annual energy use models of variable air volume systems in commer- cial buildings. This paper provides a... was the development of empirical models of power and airflow output for parallel and series fan powered terminal units at typical operating pres- sures. An experimental setup was developed and used to test fan powered terminal units from three manufacturers...

  17. Mixture Preparation and Nitric Oxide Formation in a GDI Engine studied by Combined Laser Diagnostics and Numerical Modeling

    SciTech Connect (OSTI)

    Volker Sick; Dennis N. Assanis

    2002-11-27

    Through the combination of advanced imaging laser diagnostics with multi-dimensional computer models, a new understanding of the performance of direct-injection gasoline engines is pursuit. The work focuses on the fuel injection process, the breakup of the liquid into a fine spray and the mixing of the fuel with the in-cylinder gases. Non-intrusive laser diagnostics will be used to measure the spatial distribution of droplets and vaporized fuel with very high temporal resolution. These data along with temperature measurements will be used to validate a new spray breakup model for gasoline direct-injection. Experimental data on near wall fuel distributions will be used for comparison with a model that predicts the spray-wall interaction and the dynamics of the liquid film on the surface. Quantitative measurements of local nitric oxide concentrations inside the combustion chamber will provide a critical test for a numerical simulation of the nitric oxide formation process. This model is based on a modified flamelet approach and will be used to study the effects of exhaust gas recirculation.

  18. A new model to simulate the Martian mesoscale and microscale atmospheric circulation: Validation and first results

    E-Print Network [OSTI]

    Spiga, Aymeric

    A new model to simulate the Martian mesoscale and microscale atmospheric circulation: Validation) Mesoscale Model is a new versatile simulator of the Martian atmosphere and environment at horizontal scales, and photochemistry cycles. Since LMD-GCM large-scale simulations are also used to drive the mesoscale model

  19. The new model of chemical evolution of r-process elements based on the hierarchical galaxy formation. I. Ba and Eu

    SciTech Connect (OSTI)

    Komiya, Yutaka; Suda, Takuma [National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo 181-8588 (Japan); Yamada, Shimako [Department of Cosmoscience, Hokkaido University, Sapporo, Hokkaido 060-0810 (Japan); Fujimoto, Masayuki Y. [Nuclear reaction data center, Graduate School of Science, Hokkaido University, Sapporo, Hokkaido 060-0810 (Japan)

    2014-03-10

    We investigate the chemical enrichment of r-process elements in the early evolutionary stages of the Milky Way halo within the framework of hierarchical galaxy formation using a semi-analytic merger tree. In this paper, we focus on heavy r-process elements, Ba and Eu, of extremely metal-poor (EMP) stars and give constraints on their astronomical sites. Our models take into account changes of the surface abundances of EMP stars by the accretion of interstellar medium (ISM). We also consider metal-enrichment of intergalactic medium by galactic winds and the resultant pre-enrichment of proto-galaxies. The trend and scatter of the observed r-process abundances are well reproduced by our hierarchical model with ?10% of core-collapse supernovae in low-mass end (?10 M {sub ?}) as a dominant r-process source and the star formation efficiency of ?10{sup –10} yr{sup –1}. For neutron star mergers as an r-process source, their coalescence timescale has to be ?10{sup 7} yr, and the event rates ?100 times larger than currently observed in the Galaxy. We find that the accretion of ISM is a dominant source of r-process elements for stars with [Ba/H] < –3.5. In this model, a majority of stars at [Fe/H] < –3 are formed without r-process elements, but their surfaces are polluted by the ISM accretion. The pre-enrichment affects ?4% of proto-galaxies, and yet, is surpassed by the ISM accretion in the surface of EMP stars.

  20. The combined use of sequence stratigraphy and stochastic modelling to reservoir management of the Ness Formation, Statfjord Field, Norwegian North Sea. Part 2: Stochastic modelling

    SciTech Connect (OSTI)

    Svanes, T.; Sundt, O.; Skarnes, P.I. [Statoil, Stavanger (Norway)] [and others

    1995-08-01

    In recent years probabilistic modelling of reservoir heterogeneities has become an integrated part of reservoir description, and various methods and software programs have been introduced. In general, the process of generating a stochastic 3D model consists of four stages: (1) simulate isochore maps of each time-zone, (2) distribute facies heterogeneities within the isochores, (3) simulate petrophysical properties and (4) translate the fine-scale model to a coarser flow simulation grid. Based on interpreted sequence stratigraphic zonation and facies distribution the Ness Formation was subdivided into 13 modelling zones. In most cases a modelling zone consists of lowstand deposits or combined transgressive and highstand deposits. Each zone was modelled independently because they represent individual sedimentary characteristics. The time-zone thicknesses were simulated using moving average method conditioning to wells, including anisotropy, trend and variogram. An integrated stochastic reservoir modelling package called STORM was applied perforating steps 2, 3, and 4. Different facies algorithms are available and a marked point process designed for fluvial systems was used to model the lowstand time-zones. For the combined transgressive and highstand zones a semi-Markov method, suitable for shallow marine systems, was applied. The aim of the stochastic modelling work was threefold: (1) to make realistic fine-scale geological models that are consistent with observed data and geological understanding, (2) to calculate uncertainties in oil in place volume and (3) to match production history to be able to predict future reservoir behaviour and detect unswept oil. Latest simulation data will be presented and discussed at the conference.

  1. An empirical behavioral model of price formation Szabolcs Mike1, 2

    E-Print Network [OSTI]

    order placement is symmetric, independent of the bid-ask spread, and the same for buying and selling. We on price data, the model produces good predictions for the magnitude and functional form with the mainstream paradigm, but it fails to provide a positive alternative with quantitative predictive power2

  2. MODELING OF POROSITY FORMATION IN ALUMINUM ALLOYS Kent D. Carlson1

    E-Print Network [OSTI]

    Beckermann, Christoph

    that each volume element in the casting is composed of some combination of solid metal (s), liquid metal (l alloys. The model predicts the amount and size of the porosity in a solidified casting. Computation correspondence. Introduction Porosity-related defects are a major cause of casting rejection and re

  3. A trainable trajectory formation model TD-HMM parameterized for the LIPS 2008 challenge

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    agents ­ virtual characters as well as anthropoid robots ­ should be able to talk with their human. Index Terms: facial animation audiovisual speech synthesis, HMM 1. Introduction Embodied conversational model of the robot). Human interlocutors are very sensitive to discrepancies between the visible

  4. Fluctuation level bursts in a model of internal transport barrier formation D. Lopez-Bruna, D. E. Newman, and B. A. Carreras

    E-Print Network [OSTI]

    Newman, David

    features of ITB models the phase transition character with a power threshold, barrier front propagation radial electric field.10,11 As happens with the edge transport barriers, the system reacts to the extraFluctuation level bursts in a model of internal transport barrier formation D. Lo´pez-Bruna, D. E

  5. Model for the formation of longshore sand ridges on the Continental Shelf: The interaction of internal waves and the bottom topography

    SciTech Connect (OSTI)

    Restrepo, J.M. [Argonne National Lab., IL (United States); Bona, J.L. [Pennsylvania State Univ., University Park, PA (United States)

    1994-01-05

    Longshore sand ridges are frequently observed to occur on the continental shelf where the overlying ocean is stratified. This study formulates a model for the formation and evolution of three-dimensional longshore sand ridges on the continental shelf. The model is based on the interaction of interfacial, weakly nonlinear waves in a stratified ocean with the sedimentary bottom topography.

  6. Image formation modeling in cryo-electron microscopy Milos Vulovic a,b

    E-Print Network [OSTI]

    van Vliet, Lucas J.

    of structural de- tail that can be obtained by cryo-EM is largely limited by specimen heterogeneity dam- age which limits the integrated electron flux that can be used, resulting in a poor signal

  7. Modeling Biogeochemistry and Flow within Heterogeneous Formations in Variably-Saturated Media 

    E-Print Network [OSTI]

    Arora, Bhavna

    2012-10-19

    parameters. To evaluate the effect of heterogeneity on redox processes, repacked soil columns with homogeneous and heterogeneous (layered) profiles from soil cores collected at the Norman Landfill site, Oklahoma, USA were employed. Results indicate...

  8. Modeling the Capacity and Emissions Impacts of Reduced Electricity Demand. Part 1. Methodology and Preliminary Results.

    E-Print Network [OSTI]

    Coughlin, Katie

    2013-01-01

    2011).pdf. ———. 2012a. “Annual Energy Outlook (AEO) 2012. ”2013. “Annual Energy Outlook - Model Documentation. ”forecast, the Annual Energy Outlook (AEO) (DOE EIA 2012a).

  9. Transformation from spots to waves in a model of actin pattern formation

    E-Print Network [OSTI]

    Stephen Whitelam; Till Bretschneider; Nigel J. Burroughs

    2009-05-18

    Actin networks in certain single-celled organisms exhibit a complex pattern-forming dynamics that starts with the appearance of static spots of actin on the cell cortex. Spots soon become mobile, executing persistent random walks, and eventually give rise to traveling waves of actin. Here we describe a possible physical mechanism for this distinctive set of dynamic transformations, by equipping an excitable reaction-diffusion model with a field describing the spatial orientation of its chief constituent (which we consider to be actin). The interplay of anisotropic actin growth and spatial inhibition drives a transformation at fixed parameter values from static spots to moving spots to waves.

  10. Modeling of Reoxidation Inclusion Formation During Filling of Steel Castings Kent D. Carlson and Christoph Beckermann

    E-Print Network [OSTI]

    Beckermann, Christoph

    in the mold cavity during filling (see Figure 1b). The growth of inclusions is determined by the Defect into the mold at the inlet and/or nucleate on the metal free surface, where contact with oxygen from to the removal of inclusions and the repair of the resulting defect areas with weld metal. Inclusions that remain

  11. A COMPARISON BETWEEN GLOBAL SOLAR MAGNETOHYDRODYNAMIC AND POTENTIAL FIELD SOURCE SURFACE MODEL RESULTS

    E-Print Network [OSTI]

    California at Berkeley, University of

    A COMPARISON BETWEEN GLOBAL SOLAR MAGNETOHYDRODYNAMIC AND POTENTIAL FIELD SOURCE SURFACE MODEL of the solar corona are (1) potential field source surface (PFSS) models, and (2) magnetohydrodynamic (MHD ABSTRACT The large-scale, steady-state magnetic field configuration of the solar corona is typically

  12. Results for the strong coupling lattice Schwinger model with Wilson fermions from a study of the equivalent loop model

    E-Print Network [OSTI]

    Scharnhorst, Klaus

    lattice with a bending rigidity 1/2. The present paper applies two approximate analytical methods precisely which also can be understood as a self-avoiding loop model on the square lattice with a bending­31 . Somewhat less attention has been paid so far to the self-avoiding loop model with a variable bending

  13. Combined results of searches for the standard model Higgs boson in pp collisions at ?s = 7 TeV

    E-Print Network [OSTI]

    Alver, B.

    Combined results are reported from searches for the standard model Higgs boson in proton–proton collisions at ?s = 7 TeV in five Higgs boson decay modes: ??, bb, ?? , WW, and ZZ. The explored Higgs boson mass range is ...

  14. A simple model for nanofiber formation by rotary jet-spinning

    E-Print Network [OSTI]

    Paula Mellado; Holly A. McIlwee; Mohammad R. Badrossamay; Josue A. Goss; L. Mahadevan; K Parker

    2012-02-12

    Nanofibers are microstructured materials that span a broad range of applications from tissue engineering scaffolds to polymer transistors. An efficient method of nanofiber production is Rotary Jet-Spinning (RJS), consisting of a perforated reservoir rotating at high speeds along its axis of symmetry, which propels a liquid, polymeric jet out of the reservoir orifice. These jets undergo stretching and solidify forming nanoscale fibers. We report a minimal scaling framework complemented by a semi-analytic and numerical approach to characterize the regimes of nanofiber production using RJS. Our theoretical model is validated for the fiber radius as a function of experimentally tunable parameters. We summarize our findings in a phase diagram for the design space of continuous nanofibers as a function of process parameters, in good agreement with experiments and with natural implications for the production rates as well as in the morphological quality of fibers.

  15. Global distribution and sources of dissolved inorganic nitrogen export to the coastal zone: Results from a spatially explicit, global model

    E-Print Network [OSTI]

    Seitzinger, Sybil

    Global distribution and sources of dissolved inorganic nitrogen export to the coastal zone: Results dissolved inorganic nitrogen (DIN) export by rivers to coastal waters (NEWS-DIN). NEWS-DIN was developed as part of an internally consistent suite of global nutrient export models. Modeled and measured DIN

  16. Controls on advance of tidewater glaciers: results from numerical modeling applied to Columbia Glacier

    E-Print Network [OSTI]

    Nick, F. M.; van der Veen, Cornelis J.; Oerlemans, J.

    2007-07-11

    at the glacier terminus and presented the flotation model. In the flotation model the terminus position is defined as the point where the ice thickness exceeds the flotation thickness by an amount H0. If the glacier thins, the terminus will retreat to a point... where this condition is again satisfied. Vieli et al. [2001] modified the flotation criterion and defined the thickness in excess of flotation H0 as a fraction of the flotation thickness. A recent modeling study by Nick and Oerlemans [2006] compared both...

  17. Headcut retreat resulting from plunge pool erosion in a 3D landscape evolution model

    E-Print Network [OSTI]

    Flores Cervantes, Javier Homero, 1977-

    2004-01-01

    Headcut retreat produced by plunge pools is represented using existing concepts about this type of erosion. The model estimates retreat rates, given flow, height of the headcut, upstream slope and Manning's roughness, and ...

  18. RHF RELAP5 Model and Preliminary Loss-Of-Offsite-Power Simulation Results for LEU Conversion

    SciTech Connect (OSTI)

    Licht, J. R.; Bergeron, A.; Dionne, B.; Thomas, F.

    2014-08-01

    The purpose of this document is to describe the current state of the RELAP5 model for the Institut Laue-Langevin High Flux Reactor (RHF) located in Grenoble, France, and provide an update to the key information required to complete, for example, simulations for a loss of offsite power (LOOP) accident. A previous status report identified a list of 22 items to be resolved in order to complete the RELAP5 model. Most of these items have been resolved by ANL and the RHF team. Enough information was available to perform preliminary safety analyses and define the key items that are still required. Section 2 of this document describes the RELAP5 model of RHF. The final part of this section briefly summarizes previous model issues and resolutions. Section 3 of this document describes preliminary LOOP simulations for both HEU and LEU fuel at beginning of cycle conditions.

  19. Neural networks as nonlinear models in Air Force personnel analysis: a prospectus and exploratory results 

    E-Print Network [OSTI]

    Wiggins, Vince L.

    1996-01-01

    recently demonstrated capabilities in areas important to personnel research such as statistical analysis, decision modeling, control, and forecasting. An extensive review of the neural network literature indicates that these networks have proven superior...

  20. Diurnal cycle of air pollution in the Kathmandu Valley, Nepal: 2. Modeling results

    E-Print Network [OSTI]

    Panday, Arnico K.

    After completing a 9-month field experiment studying air pollution and meteorology in the Kathmandu Valley, Nepal, we set up the mesoscale meteorological model MM5 to simulate the Kathmandu Valley's meteorology with a ...

  1. Performance of VAV Fan Powered Terminal Units: Experimental Results and Models for Parallel Units 

    E-Print Network [OSTI]

    Furr, J.; O'Neal, D.; Davis, M.; Bryant, J.; Cramlet, A.

    2008-01-01

    Empirical models of airflow output, power consumption, and primary airflow were developed for parallel fan powered variable air volume terminal units at typical operating pres- sures. Both 8 in. (203 mm) and 12 in. (304 mm) primary air inlet terminal units... from three manufacturers were evaluated. Generalized models were developed from the experimental data with coefficients varying by size and manufacturer. Fan power and airflow data were collected at down- stream static pressures over a range from 0...

  2. Performance of VAV Fan Powered Terminal Units: Experimental Results and Models for Series Units 

    E-Print Network [OSTI]

    Furr, J.; O'Neal, D.; Davis, M.; Bryant, J.; Cramlet, A.

    2008-01-01

    Empirical models of airflow output and power consump- tion were developed for series fan powered variable air volume terminal units at typical operating pressures. Terminal units with 8 in. (203 mm) and 12 in. (304 mm) primary air inlets from three different... manufacturers were evaluated. Generalized models were developed from the experimental data with coef- ficients varying by size and manufacturer. Fan power and airflow data were collected at downstream static pressures of 0.25 w.g. (63 Pa). Upstream static...

  3. Circumbinary planet formation in the Kepler-16 system. II. A toy model for in situ planet formation within a debris belt

    SciTech Connect (OSTI)

    Meschiari, Stefano, E-mail: stefano@astro.as.utexas.edu [McDonald Observatory, University of Texas at Austin, Austin, TX 78712 (United States)

    2014-07-20

    Recent simulations have shown that the formation of planets in circumbinary configurations (such as those recently discovered by Kepler) is dramatically hindered at the planetesimal accretion stage. The combined action of the binary and the protoplanetary disk acts to raise impact velocities between kilometer-sized planetesimals beyond their destruction threshold, halting planet formation within at least 10 AU from the binary. It has been proposed that a primordial population of 'large' planetesimals (100 km or more in size), as produced by turbulent concentration mechanisms, would be able to bypass this bottleneck; however, it is not clear whether these processes are viable in the highly perturbed circumbinary environments. We perform two-dimensional hydrodynamical and N-body simulations to show that kilometer-sized planetesimals and collisional debris can drift and be trapped in a belt close to the central binary. Within this belt, planetesimals could initially grow by accreting debris, ultimately becoming 'indestructible' seeds that can accrete other planetesimals in situ despite the large impact speeds. We find that large, indestructible planetesimals can be formed close to the central binary within 10{sup 5} yr, therefore showing that even a primordial population of 'small' planetesimals can feasibly form a planet.

  4. Impact of hydrological variations on modeling of peatland CO2 fluxes: Results from the North American Carbon Program

    E-Print Network [OSTI]

    Wisconsin at Madison, University of

    in ecosystem models due to differences in nutrients, peat properties, and plant communities. Citation: Sulman cycle due to large carbon pools resulting from the long-term accumulation of organic matter in peat of the water table exposes peat soils to oxygen, resulting in higher rates of ecosystem respiration (ER

  5. Composite CaO-Based CO2 Sorbents Synthesized by Ultrasonic Spray Pyrolysis: Experimental Results and Modeling

    E-Print Network [OSTI]

    Suslick, Kenneth S.

    Composite CaO-Based CO2 Sorbents Synthesized by Ultrasonic Spray Pyrolysis: Experimental Results by ultrasonic spray pyrolysis (USP) with both experimental results and modeling of the sorption process, even on an industrial scale.9,10 Recently, we reported the first use of ultrasonic spray pyrolysis (USP

  6. Nuclear matter equation of state in relativistic nonlinear models: results and applications

    SciTech Connect (OSTI)

    Pastor, J.; Caillon, J. C.; Labarsouque, J. [Centre d' Eludes Nucleaires de Bordeaux Gradignan, Universite Bordeaux 1, IN2P3, le Haut Vigneau, BP 120, 33175 Gradignan Cedex (France)

    2006-06-19

    We have determined the equation of state of nuclear matter according to relativistic non-linear models. In particular, we are interested in regions of high density and/or high temperature, in which the thermodynamic functions have different behaviours depending on which model one used. As applications, we have determined the maximal mass of neutron stars and studied the process of two-pion annihilation into e+e- pairs in dense and hot matter. We have found that these two observables are strongly sensitive to the nonlinear self-coupling terms of the Lagragian.

  7. The Great Sand Dunes Ecosystem Elk and Bison Carrying Capacity Model: Description and Scenario Results

    E-Print Network [OSTI]

    Boone, Randall B.

    1 The Great Sand Dunes Ecosystem Elk and Bison Carrying Capacity Model: Description and Scenario studying the Sand Dunes ecosystem in the past decade. The information they have gathered has been.S. Geological Survey, and Great Sand Dunes National Park and Preserve for providing funding to support

  8. Case Studies Comparing System Advisor Model (SAM) Results to Real Performance Data: Preprint

    SciTech Connect (OSTI)

    Blair, N.; Dobos, A.; Sather, N.

    2012-06-01

    NREL has completed a series of detailed case studies comparing the simulations of the System Advisor Model (SAM) and measured performance data or published performance expectations. These case studies compare PV measured performance data with simulated performance data using appropriate weather data. The measured data sets were primarily taken from NREL onsite PV systems and weather monitoring stations.

  9. Evaluation of the CRITERIA Irrigation Scheme Soil Water Balance Model in Texas – Initial Results 

    E-Print Network [OSTI]

    Bonaiti, G.; Fipps, G.

    2011-01-01

    High Plains, the model was calibrated and compared to lysimetric data for soybean production at the USDA-ARS Laboratory, Bushland, on soybean, over a two year period (2002 and 2003). In the LRGV, data was collected from a 27-ha sugarcane field within...

  10. Computer representation of the model covariance function resulting from travel-time tomography

    E-Print Network [OSTI]

    Cerveny, Vlastislav

    Karlovu 3, 121 16 Praha 2, Czech Republic, http://sw3d.cz/sta#11;/klimes.htm Summary This paper represents generalization of the equations from interpo- lation of slowness to interpolation of general power of velocity is designed. Keywords Travel{time tomographic inversion, resolution, velocity model, medium covariance func

  11. A Recipe for Galaxy Formation Shaun Cole

    E-Print Network [OSTI]

    Alfonso Aragon-Salamanca; Carlos S. Frenk; Julio F. Navarro; Stephen E. Zepf

    1994-02-01

    We present a detailed prescription for how galaxy formation can be modelled in hierarchical theories of structure formation. Our model incorporates the formation and merging of dark matter halos, the shock heating and radiative cooling of baryonic gas gravitationally confined in these halos, the formation of stars regulated by the energy released by evolving stars and supernovae, the merging of galaxies within dark matter halos, and the spectral evolution of the stellar populations that are formed. The procedure that we describe is very flexible and can be applied to any hierarchical clustering theory. We explore the effects of varying the stellar initial mass function, star formation rates and galaxy merging. The results we compare with an extensive range of observational data, including the B and K galaxy luminosity functions, galaxy colours, the Tully-Fisher relation and galaxy number counts.These data strongly constrain the models and enable the relative importance of each of the physical process to be assessed. We present a broadly successful model defined by a plausible choice of parameters. This fiducial model produces a much more acceptable luminosity function than most previous studies. This is achieved through a modest rate of galaxy mergers and strong suppression of star formation in halos of low circular velocity. However, it fails to produce galaxies as red as many observed ellipticals and, compared with the observed Tully-Fisher relation, the model galaxies have circular velocities which are too large. ** uuencoded compressed postscript file containing all text and figures.**

  12. Water Formatics Engineered formation of nanobubbles networks

    E-Print Network [OSTI]

    Jacob, Eshel Ben

    Water Formatics Engineered formation of nanobubbles networks in water and aqueous solutions We present the idea that the anomalous effects of rf-treatments of water and aqueous solution resulted from-bubble exchange interactions. These exchange interactions are mediated by the ordering of the water molecules

  13. An assessment of possible climate change in the Australian region based on intercomparison of general circulation modeling results

    SciTech Connect (OSTI)

    Whetton, P.H.; Pittock, A.B.; Haylock, M.R. ); Rayner, P.J. )

    1994-03-01

    To assist in estimating likely future climate change in the Australian region, the authors examine the results of four different general circulation modeling experiments run to assess the equilibrium impact of doubling greenhouse gases. The results examined were the most recent available at the time of study from various research centers in North America and Europe, as well as those of the Commonwealth Scientific and Industrial Research Organisation (CSIRO). The approach used is, first, to assess the quality of the control (1 x CO[sub 2]) simulations from each of the models of mean sea level (MSL) pressure and precipitation in the Australian region by comparing these with the corresponding observed patterns; and, second, to then analyze the 2 x CO[sub 2] results of only those model experiments with the best control simulations. Of the models examined two are chosen on the basis of their simulation of current climate in the region: the CSIRO four-level model (CSIRO4) and the United Kingdom Meteorological Office (UKMO) model. For conditions of equivalent doubling of CO[sub 2], both models show substantial increases in surface air temperature of around 4[degrees]-6[degrees] inland and 2[degrees]-4[degrees]C in coastal regions. Both models show decreased MSL pressure over the Australian continent and increases in rainfall over northern, central, and eastern Australia, particularly in the summer half of the year. The CSIRO4 model, but not the UKMO model, also shows increased pressure to the south of the continent and decreased winter rainfall in southwest and southern Australia. Generally, field significance tests show the pattern and magnitude of the changes to be significant of CSIRO4 (for which the necessary monthly simulated data were available). 42 refs., 20 figs., 5 tabs.

  14. A mean-field monomer-dimer model with attractive interaction: Exact solution and rigorous results

    SciTech Connect (OSTI)

    Alberici, D. Contucci, P. Mingione, E.

    2014-06-15

    A mean-field monomer-dimer model which includes an attractive interaction among both monomers and dimers is introduced and its exact solution rigorously derived. The Heilmann-Lieb method for the pure hard-core interacting case is used to compute upper and lower bounds for the pressure. The bounds are shown to coincide in the thermodynamic limit for a suitable choice of the monomer density m. The computation of the monomer density is achieved by solving a consistency equation in the phase space (h, J), where h tunes the monomer potential and J the attractive potential. The critical point and exponents are computed and show that the model is in the mean-field ferromagnetic universality class.

  15. Modeling experimental results of diffusion of alkaline solutions through a compacted bentonite barrier

    SciTech Connect (OSTI)

    Fernandez, Raul; Cuevas, Jaime; Maeder, Urs K.

    2010-08-15

    The interaction between concrete/cement and swelling clay (bentonite) has been modeled in the context of engineered barrier systems for deep geological disposal of high-level radioactive waste. The geochemical transformations observed in laboratory diffusion experiments at 60 and 90 {sup o}C between bentonite and different high-pH solutions (K-Na-OH and Ca(OH){sub 2}-saturated) were reconciled with the reactive transport code CrunchFlow. For K-Na-OH solutions (pH = 13.5 at 25 {sup o}C) partial dissolution of montmorillonite and precipitation of Mg-silicates (talc-like), hydrotalcite and brucite at the interface are predicted at 60 {sup o}C, while at 90 {sup o}C the alteration is wider. Alkaline cations diffused beyond the mineralogical alteration zone by means of exchange with Mg{sup 2+} in the interlayer region of montmorillonite. Very slow reactivity and minor alteration of the clay are predicted in the Ca(OH){sub 2}-bentonite system. The model is a reasonable description of the experiments but also demonstrates the difficulties in modeling processes operating at a small scale under a diffusive regime.

  16. Megacity impacts on regional ozone formation: observations and WRF-Chem modeling for the MIRAGE-Shanghai field campaign

    E-Print Network [OSTI]

    2013-01-01

    Tie, X. : Analysis of ozone and VOCs measured in Shanghai: AMegacity impacts on regional ozone formation terminations inand Tie, X. : Study of ozone “weekend effect” in Shanghai,

  17. Preprint version -final, definitive version available at http://ijr.sagepub.com/ accepted for IJRR, Sep. 2012 Modeling and Control of UAV Bearing-Formations

    E-Print Network [OSTI]

    , Sep. 2012 Modeling and Control of UAV Bearing-Formations with Bilateral High-Level Steering Antonio Abstract--In this paper we address the problem of controlling the motion of a group of UAVs bound to keep of the UAV performance. The proposed theoretical framework is extensively validated by means of simulations

  18. Using MiniBooNE neutral current elastic cross section results to constrain 3+1 sterile neutrino models

    E-Print Network [OSTI]

    Callum Wilkinson; Susan Cartwright; Lee Thompson

    2014-01-10

    The MiniBooNE Neutral Current Elastic (NCEL) cross section results are used to extract limits in the $\\Delta m^{2}-\\sin^{2}\\vartheta_{\\mu s}$ plane for a 3+1 sterile neutrino model with a mass splitting $0.1 \\leq \\Delta m^{2} \\leq 10.0$ eV$^{2}$. GENIE is used with a cross section model close to the one employed by MiniBooNE to make event rate predictions using simulations on the MiniBooNE target material CH$_{2}$. The axial mass is a free parameter in all fits. Sterile modifications to the flux and changes to the cross section in the simulation relate the two and allow limits to be set on sterile neutrino mixing using cross section results. The large axial mass problem makes it necessary for experiments to perform their own axial mass fits, but a prior fit to the same dataset could mask a sterile oscillation signal if the sterile and cross section model parameters are not independent. We find that for the NCEL dataset there are significant correlations between the sterile and cross section model parameters, making a fit to both models simultaneously necessary to get robust results. Failure to do this results in stronger than warranted limits on the sterile parameters. The general problems that the current uncertainty on charged-current quasi-elastic (CCQE) and NCEL cross sections at MiniBooNE energies pose for sterile neutrino measurements are discussed.

  19. Observation and modeling of polycrystalline grain formation in Ge{sub 2}Sb{sub 2}Te{sub 5}

    SciTech Connect (OSTI)

    Burr, Geoffrey W.; Tchoulfian, Pierre; Topuria, Teya; Nyffeler, Clemens; Virwani, Kumar; Padilla, Alvaro; Shelby, Robert M.; Eskandari, Mona; Jackson, Bryan; Lee, Bong-Sub

    2012-05-15

    The relationship between the polycrystalline nature of phase change materials (such as Ge{sub 2}Sb{sub 2}Te{sub 5}) and the intermediate resistance states of phase change memory (PCM) devices has not been widely studied. A full understanding of such states will require knowledge of how polycrystalline grains form, how they interact with each other at various temperatures, and how the differing electrical (and thermal) characteristics within the grains and at their boundaries combine through percolation to produce the externally observed electrical (and thermal) characteristics of a PCM device. We address the first of these tasks (and introduce a vehicle for the second) by studying the formation of fcc polycrystalline grains from the as-deposited amorphous state in undoped Ge{sub 2}Sb{sub 2}Te{sub 5}. We perform ex situ transmission electron microscopy membrane experiments and then match these observations against numerical simulation. Ramped-anneal experiments show that the temperature ramp-rate strongly influences the median grain size. By truncating such ramped-anneal experiments at various peak temperatures, we convincingly demonstrate that the temperature range over which these grains are established is quite narrow. Subsequent annealing at elevated temperature appears to change these established distributions of grain sizes only slightly. Our numerical simulator--which models nuclei formation through classical nucleation theory and then tracks the subsequent time- and temperature-dependent growth of these grains--can match these experimental observations of initial grain distributions and crystallization temperature both qualitatively and quantitatively. These simulations show that the particular narrow temperature range over which crystallization occurs shifts as a function of temperature ramp-rate, which allows us to quantify the lower portions of the time-temperature-transformation map for Ge{sub 2}Sb{sub 2}Te{sub 5}. Future experiments and extensions of the simulator to investigate temperature-dependent interactions between neighboring grains, and to study nucleation from within the melt-quenched amorphous state, are discussed.

  20. Modeling Multiple Time Scales during Glass Formation with Phase-Field Crystals Joel Berry and Martin Grant

    E-Print Network [OSTI]

    Grant, Martin

    describe several aspects of glass formation over multiple time scales. Agreement with mode coupling theory is related to the liquid bulk modulus, qi sets the equilibrium distance between particles of the same species) The dynamics of glass formation in monatomic and binary liquids are studied numerically using a microscopic

  1. Membrane adhesion and domain formation

    E-Print Network [OSTI]

    Thomas R. Weikl; Reinhard Lipowsky

    2007-09-23

    We review theoretical results for the adhesion-induced phase behavior of biomembranes. The focus is on models in which the membranes are represented as discretized elastic sheets with embedded adhesion molecules. We present several mechanism that lead to the formation of domains during adhesion, and discuss the time-dependent evolution of domain patterns obtained in Monte-Carlo simulations. The simulated pattern dynamics has striking similarities to the pattern evolution observed during T cell adhesion.

  2. Hubble Tarantula Treasury Project. III. Photometric Catalog and Resulting Constraints on the Progression of Star Formation in the 30 Doradus Region

    E-Print Network [OSTI]

    Sabbi, E; Anderson, J; Cignoni, M; van der Marel, R P; Zaritsky, D; de Marchi, G; Panagia, N; Gouliermis, D A; Grebel, E K; Gallager, J S; Smith, L J; Sana, H; Aloisi, A; Tosi, M; Evans, C J; Arab, H; Boyer, M; de Mink, S E; Gordon, K; Koekemoer, A M; Larsen, S S; Ryon, J E; Zeidler, P

    2015-01-01

    We present and describe the astro-photometric catalog of more than 800,000 sources found in the Hubble Tarantula Treasury Project (HTTP). HTTP is a Hubble Space Telescope (HST) Treasury program designed to image the entire 30 Doradus region down to the sub-solar (~0.5 solar masses) mass regime using the Wide Field Camera 3 (WFC3) and the Advanced Camera for Surveys (ACS). We observed 30 Doradus in the near ultraviolet (F275W, F336W), optical (F555W, F658N, F775W), and near infrared (F110W, F160W) wavelengths. The stellar photometry was measured using point-spread function (PSF) fitting across all the bands simultaneously. The relative astrometric accuracy of the catalog is 0.4 mas. The astro-photometric catalog, results from artificial star experiments and the mosaics for all the filters are available for download. Color-magnitude diagrams are presented showing the spatial distributions and ages of stars within 30 Dor as well as in the surrounding fields. HTTP provides the first rich and statistically signifi...

  3. Loop formation in polymers in crowded environment

    E-Print Network [OSTI]

    K. Haydukivska; V. Blavatska

    2015-11-12

    We analyze the probability of a single loop formation in a long flexible polymer chain in disordered environment in $d$ dimensions. The structural defects are considered to be correlated on large distances $r$ according to a power law $\\sim r^{-a}$. Working within the frames of continuous chain model and applying the direct polymer renormalization scheme, we obtain the values of critical exponents governing the scaling of probabilities of loop formation with various positions along the chain as function of loops length. Our results quantitatively reveal that the presence of structural defects in environment decreases the probability of loop formation in polymer macromolecules.

  4. Sequentially Triggered Star Formation in OB Associations

    E-Print Network [OSTI]

    Thomas Preibisch; Hans Zinnecker

    2006-10-27

    We discuss observational evidence for sequential and triggered star formation in OB associations. We first review the star formation process in the Scorpius-Centaurus OB association, the nearest OB association to the Sun, where several recent extensive studies have allowed us to reconstruct the star formation history in a rather detailed way. We then compare the observational results with those obtained for other OB associations and with recent models of rapid cloud and star formation in the turbulent interstellar medium. We conclude that the formation of whole OB subgroups (each consisting of several thousand stars) requires large-scale triggering mechanisms such as shocks from expanding wind and supernova driven superbubbles surrounding older subgroups. Other triggering mechanisms, like radiatively driven implosion of globules, also operate, but seem to be secondary processes, forming only small stellar groups rather than whole OB subgroups with thousands of stars.

  5. Models of the Morphology, Kinematics, and Star Formation History of the Prototypical Collisional Starburst System: NGC 7714/7715 = Arp 284

    E-Print Network [OSTI]

    Curtis Struck; Beverly J. Smith

    2003-01-31

    (abridged) We present new N-body, hydrodynamical simulations of the interaction between the starburst galaxy NGC 7714 and its post-starburst companion NGC 7715, focusing on the formation of the collisional features, including: 1) the gas-rich star forming bridge, 2) the large gaseous loop (and stellar tails) to the west of the system, 3) the very extended HI tail to the west and north of NGC 7714, and 4) the partial stellar ring in NGC 7714. Our simulations confirm the results of earlier work that an off-center inclined collision between two disk galaxies is almost certainly responsible for the peculiar morphologies of this system. However, we have explored a wider set of initial galaxy and collisional encounter parameters than previously, and have found a relatively narrow range of parameters that reproduce all the major morphologies of this system. The simulations suggest specific mechanisms for the development of several unusual structures. We find that the complex gas bridge has up to four distinct components, with gas contributed from two sides of NGC 7715, as well as from NGC 7714. The observed gas-star offset in this bridge is accounted for in the simulations by the dissipative evolution of the gas. The models also indicate that the low surface brightness HI tail to the far west of NGC 7714 is the end of the NGC 7715 countertail, curved behind the two galaxies. Spectral evolutionary models of the NGC 7714 core by Lan\\c{c}on et al. suggest the possibility of multiple starbursts in the last 300 Myr. Our hydrodynamic models suggest that bursts could be triggered by induced ring-like waves, and a post-collision buildup of gas in the core of the galaxy.

  6. Reactive Power Laboratory: Synchronous Condenser Testing&Modeling Results - Interim Report

    SciTech Connect (OSTI)

    Henry, SD

    2005-09-27

    The subject report documents the work carried out by Oak Ridge National Laboratory (ORNL) during months 5-7 (May-July 2005) of a multi-year research project. The project has the overall goal of developing methods of incorporating distributed energy (DE) that can produce reactive power locally and for injecting into the distribution system. The objective for this new type of DE is to be able to provide voltage regulation and dynamic reactive power reserves without the use of extensive communication and control systems. The work performed over this three-month period focused on four aspects of the overall objective: (1) characterization of a 250HP (about 300KVAr) synchronous condenser (SC) via test runs at the ORNL Reactive Power Laboratory; (2) development of a data acquisition scheme for collecting the necessary voltage, current and power readings at the synchronous condenser and on the distribution system; (3) development of algorithms for analyzing raw test data from the various test runs; and (4) validation of a steady-state model for the synchronous condenser via the use of a commercial software package to study its effects on the ORNL 13.8/2.4kV distribution network.

  7. ADMP Mixing of Tank 18F: History, Modeling, Testing, and Results

    SciTech Connect (OSTI)

    LEISHEAR, ROBERTA

    2004-03-29

    Residual radioactive waste was removed from Tank 18F in the F-Area Tank Farm at Savannah River Site (SRS), using the advanced design mixer pump (ADMP). Known as a slurry pump, the ADMP is a 55 foot long pump with an upper motor mounted to a steel super structure, which spans the top of the waste tank. The motor is connected by a long vertical drive shaft to a centrifugal pump, which is submerged in waste near the tank bottom. The pump mixes, or slurries, the waste within the tank so that it may be transferred out of the tank. Tank 18F is a 1.3 million gallon, 85 foot diameter underground waste storage tank, which has no internal components such as cooling coils or structural supports. The tank contained a residual 47,000 gallons of nuclear waste, consisting of a gelatinous radioactive waste known as sludge and particulate zeolite. The prediction of the ADMP success was based on nearly twenty five years of research and the application of that research to slurry pump technology. Many personnel at SRS and Pacific Northwest National Laboratories (PNNL) have significantly contributed to these efforts. This report summarizes that research which is pertinent to the ADMP performance in Tank 18F. In particular, a computational fluid dynamics (CFD) model was applied to predict the performance of the ADMP in Tank 18F.

  8. Uncertainty and sensitivity analysis of early exposure results with the MACCS Reactor Accident Consequence Model

    SciTech Connect (OSTI)

    Helton, J.C.; Johnson, J.D.; McKay, M.D.; Shiver, A.W.; Sprung, J.L.

    1995-01-01

    Uncertainty and sensitivity analysis techniques based on Latin hypercube sampling, partial correlation analysis and stepwise regression analysis are used in an investigation with the MACCS model of the early health effects associated with a severe accident at a nuclear power station. The primary purpose of this study is to provide guidance on the variables to be considered in future review work to reduce the uncertainty in the important variables used in the calculation of reactor accident consequences. The effects of 34 imprecisely known input variables on the following reactor accident consequences are studied: number of early fatalities, number of cases of prodromal vomiting, population dose within 10 mi of the reactor, population dose within 1000 mi of the reactor, individual early fatality probability within 1 mi of the reactor, and maximum early fatality distance. When the predicted variables are considered collectively, the following input variables were found to be the dominant contributors to uncertainty: scaling factor for horizontal dispersion, dry deposition velocity, inhalation protection factor for nonevacuees, groundshine shielding factor for nonevacuees, early fatality hazard function alpha value for bone marrow exposure, and scaling factor for vertical dispersion.

  9. Evaluation of Model Results and Measured Performance of Net-Zero Energy Homes in Hawaii: Preprint

    SciTech Connect (OSTI)

    Norton, P.; Kiatreungwattana, K.; Kelly, K. J.

    2013-03-01

    The Kaupuni community consists of 19 affordable net-zero energy homes that were built within the Waianae Valley of Oahu, Hawaii in 2011. The project was developed for the native Hawaiian community led by the Department of Hawaiian Homelands. This paper presents a comparison of the modeled and measured energy performance of the homes. Over the first year of occupancy, the community as a whole performed within 1% of the net-zero energy goals. The data show a range of performance from house to house with the majority of the homes consistently near or exceeding net-zero, while a few fall short of the predicted net-zero energy performance. The impact of building floor plan, weather, and cooling set point on this comparison is discussed. The project demonstrates the value of using building energy simulations as a tool to assist the project to achieve energy performance goals. Lessons learned from the energy performance monitoring has had immediate benefits in providing feedback to the homeowners, and will be used to influence future energy efficient designs in Hawaii and other tropical climates.

  10. Linking fish and fluid behavior: Results from a physical model of turbulence and bioenergetics around large wood in rivers

    E-Print Network [OSTI]

    Tullos, Desiree

    Linking fish and fluid behavior: Results from a physical model of turbulence and bioenergetics the hydraulics around and fish use of large wood is lacking. Fish energetically balance the need for predation are controlled, we hypothesized that fish behavioral patches will be driven by turbulence intensity

  11. NIF Periscope Wall Modal Study Comparison of Results for 2 FEA Models with 2 Modal Tests

    SciTech Connect (OSTI)

    Eli, M W; Gerhard, M A; Lee, C L; Sommer, S C; Woehrle, T G

    2000-10-26

    This report summarizes experimentally and numerically determined modal properties for one of the reinforced concrete end walls of the NIF Periscope Support Structure in Laser Bay 1. Two methods were used to determine these modal properties: (1) Computational finite-element analyses (modal extraction process); and (2) Experimental modal analysis based on measured test data. This report also includes experimentally determined modal properties for a prototype LM3/Polarizer line-replaceable unit (LRU) and a prototype PEPC LRU. Two important parameters, used during the design phase, are validated through testing [ref 1]. These parameters are the natural frequencies and modal damping (of the system in question) for the first several global modes of vibration. Experimental modal testing provides these modal values, along with the corresponding mode shapes. Another important parameter, the input excitation (expected during normal operation of the NIF laser system) [ref 1], can be verified by performing a series of ambient vibration measurements in the vicinity of the particular system (or subsystem) of interest. The topic of ambient input excitation will be covered in a separate report. Due to the large mass of the Periscope Pedestal, it is difficult to excite the entire series of Periscope Pedestal Walls all at once. It was decided that the experimental modal tests would be performed on just one Periscope End Wall in Laser Bay 1. Experimental modal properties for the Periscope End Wall have been used to validate and update the FE analyses. Results from the analyses and modal tests support the conclusion that the Periscope Pedestal will not exceed the stability budget, which is described in reference 1. The results of the modal tests for the Periscope End Wall in Laser Bay 1 have provided examples of modal properties that can be derived from future modal tests of the entire Periscope Assembly (excluding the LRU's). This next series of larger modal tests can be performed after the support structure for the Periscope Assembly has been completed. There are five optical elements in the Periscope Assembly: PEPC; Polarizer; LM3; LM2; and the Periscope Light Source. All of these optical elements have stability requirements except for the PEPC. During the Title II Design phase, two prototypes of the LM3/Polarizer LRU were used in two different series of modal tests [ref 2,3]. A similar series of modal tests were conducted on a prototype of the PEPC LRU. The results of the modal tests were used to verify the modal properties assumed for use in the corresponding finite-element analyses.

  12. Uncertainty and sensitivity analysis of food pathway results with the MACCS Reactor Accident Consequence Model

    SciTech Connect (OSTI)

    Helton, J.C.; Johnson, J.D.; Rollstin, J.A.; Shiver, A.W.; Sprung, J.L.

    1995-01-01

    Uncertainty and sensitivity analysis techniques based on Latin hypercube sampling, partial correlation analysis and stepwise regression analysis are used in an investigation with the MACCS model of the food pathways associated with a severe accident at a nuclear power station. The primary purpose of this study is to provide guidance on the variables to be considered in future review work to reduce the uncertainty in the important variables used in the calculation of reactor accident consequences. The effects of 87 imprecisely-known input variables on the following reactor accident consequences are studied: crop growing season dose, crop long-term dose, milk growing season dose, total food pathways dose, total ingestion pathways dose, total long-term pathways dose, area dependent cost, crop disposal cost, milk disposal cost, condemnation area, crop disposal area and milk disposal area. When the predicted variables are considered collectively, the following input variables were found to be the dominant contributors to uncertainty: fraction of cesium deposition on grain fields that is retained on plant surfaces and transferred directly to grain, maximum allowable ground concentrations of Cs-137 and Sr-90 for production of crops, ground concentrations of Cs-134, Cs-137 and I-131 at which the disposal of milk will be initiated due to accidents that occur during the growing season, ground concentrations of Cs-134, I-131 and Sr-90 at which the disposal of crops will be initiated due to accidents that occur during the growing season, rate of depletion of Cs-137 and Sr-90 from the root zone, transfer of Sr-90 from soil to legumes, transfer of Cs-137 from soil to pasture, transfer of cesium from animal feed to meat, and the transfer of cesium, iodine and strontium from animal feed to milk.

  13. Uncertainty and sensitivity analysis of chronic exposure results with the MACCS reactor accident consequence model

    SciTech Connect (OSTI)

    Helton, J.C.; Johnson, J.D.; Rollstin, J.A.; Shiver, A.W.; Sprung, J.L.

    1995-01-01

    Uncertainty and sensitivity analysis techniques based on Latin hypercube sampling, partial correlation analysis and stepwise regression analysis are used in an investigation with the MACCS model of the chronic exposure pathways associated with a severe accident at a nuclear power station. The primary purpose of this study is to provide guidance on the variables to be considered in future review work to reduce the uncertainty in the important variables used in the calculation of reactor accident consequences. The effects of 75 imprecisely known input variables on the following reactor accident consequences are studied: crop growing season dose, crop long-term dose, water ingestion dose, milk growing season dose, long-term groundshine dose, long-term inhalation dose, total food pathways dose, total ingestion pathways dose, total long-term pathways dose, total latent cancer fatalities, area-dependent cost, crop disposal cost, milk disposal cost, population-dependent cost, total economic cost, condemnation area, condemnation population, crop disposal area and milk disposal area. When the predicted variables are considered collectively, the following input variables were found to be the dominant contributors to uncertainty: dry deposition velocity, transfer of cesium from animal feed to milk, transfer of cesium from animal feed to meat, ground concentration of Cs-134 at which the disposal of milk products will be initiated, transfer of Sr-90 from soil to legumes, maximum allowable ground concentration of Sr-90 for production of crops, fraction of cesium entering surface water that is consumed in drinking water, groundshine shielding factor, scale factor defining resuspension, dose reduction associated with decontamination, and ground concentration of 1-131 at which disposal of crops will be initiated due to accidents that occur during the growing season.

  14. A Comparison of TWP-ICE Observational Data with Cloud-Resolving Model Results

    SciTech Connect (OSTI)

    Fridlind, A. M.; Ackerman, Andrew; Chaboureau, Jean-Pierre; Fan, Jiwen; Grabowski, Wojciech W.; Hill, A.; Jones, T. R.; Khaiyer, M. M.; Liu, G.; Minnis, Patrick; Morrison, H.; Nguyen, L.; Park, S.; Petch, Jon C.; Pinty, Jean-Pierre; Schumacher, Courtney; Shipway, Ben; Varble, A. C.; Wu, Xiaoqing; Xie, Shaocheng; Zhang, Minghua

    2012-03-13

    Observations made during the TWP-ICE campaign are used to drive and evaluate thirteen cloud-resolving model simulations with periodic lateral boundary conditions. The simulations employ 2D and 3D dynamics, one- and two-moment microphysics, several variations on large-scale forcing, and the use of observationally derived aerosol properties to prognose droplet numbers. When domain means are averaged over a 6-day active monsoon period, all simulations reproduce observed surface precipitation rate but not its structural distribution. Simulated fractional areas covered by convective and stratiform rain are uncorrelated with one another, and are both variably overpredicted by up to a factor of {approx}2. Stratiform area fractions are strongly anticorrelated with outgoing longwave radiation (OLR) but are negligibly correlated with ice water path (IWP), indicating that ice spatial distribution controls OLR more than mean IWP. Overpredictions of OLR tend to be accompanied by underpredictions of reflected shortwave radiation (RSR). When there are two simulations differing only in microphysics scheme or large-scale forcing, the one with smaller stratiform area tends to exhibit greater OLR and lesser RSR by similar amounts. After {approx}10 days, simulations reach a suppressed monsoon period with a wide range of mean precipitable water vapor, attributable in part to varying overprediction of cloud-modulated radiative flux divergence compared with observationally derived values. Differences across the simulation ensemble arise from multiple sources, including dynamics, microphysics, and radiation treatments. Close agreement of spatial and temporal averages with observations may not be expected, but the wide spreads of predicted stratiform fraction and anticorrelated OLR indicate a need for more rigorous observation-based evaluation of the underlying micro- and macrophysical properties of convective and stratiform structures.

  15. Process of Integrating Screening and Detailed Risk-based Modeling Analyses to Ensure Consistent and Scientifically Defensible Results

    SciTech Connect (OSTI)

    Buck, John W.; McDonald, John P.; Taira, Randal Y.

    2002-11-01

    To support cleanup and closure of these tanks, modeling is performed to understand and predict potential impacts to human health and the environment. Pacific Northwest National Laboratory developed a screening tool for the United States Department of Energy, Office of River Protection that estimates the long-term human health risk, from a strategic planning perspective, posed by potential tank releases to the environment. This tool is being conditioned to more detailed model analyses to ensure consistency between studies and to provide scientific defensibility. Once the conditioning is complete, the system will be used to screen alternative cleanup and closure strategies. The integration of screening and detailed models provides consistent analyses, efficiencies in resources, and positive feedback between the various modeling groups. This approach of conditioning a screening methodology to more detailed analyses provides decision-makers with timely and defensible information and increases confidence in the results on the part of clients, regulators, and stakeholders.

  16. XML-Based Formulation of Field Theoretical Models. A Proposal for a Future Standard and Data Base for Model Storage, Exchange and Cross-checking of Results

    E-Print Network [OSTI]

    A. Demichev; A. Kryukov; A. Rodionov

    2002-03-11

    We propose an XML-based standard for formulation of field theoretical models. The goal of creation of such a standard is to provide a way for an unambiguous exchange and cross-checking of results of computer calculations in high energy physics. At the moment, the suggested standard implies that models under consideration are of the SM or MSSM type (i.e., they are just SM or MSSM, their submodels, smooth modifications or straightforward generalizations).

  17. A quantitative model of trading and price formation in nancial markets Marcus G. Daniels, 1 J. Doyne Farmer, 1 L aszl o Gillemot, 1 Giulia Iori, 2 and Eric Smith 1

    E-Print Network [OSTI]

    A quantitative model of trading and price formation in #12;nancial markets Marcus G. Daniels, 1 J y (Dated: January 29, 2002) We use standard physics techniques to model trading and price formation of prices, which is the standard measure of #12;nancial risk, and the spread and price impact functions

  18. OpenEI Community - result formats

    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 APPENDIXsourceII JumpQuarterly Smart Grid Data available for downloadGRR 3rd Quarter -/0 en

  19. Help:FormattingResults | 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 E LIST OFAMERICA'SHeavy ElectricalsFTLTechnology Srl Jump to:source HistoryFacebook icon

  20. Phase formation sequences in the silicon-phosphorous system : determined by in-situ synchrotron andj conventional x-ray diffraction measurements and predicted by a theoretical model.

    SciTech Connect (OSTI)

    Carlsson, J. R. A.; Clevenger, L.; Madsen, L. D.; Hultman, L.; Li, X.-H.; Jordan-Sweet, J.; Lavoie, C.; Roy, R. A.; Cabral, C., Jr.; Morales, G.; Ludwig, K. L.; Stephenson, G. B.; Hentzell, H. T. G.; Materials Science Division; Linkoeping Univ.; IBM T. J. Watson Research Center; Boston Univ.

    1997-01-01

    The phase formation sequences of Si-P alloy thin films with P concentrations between 20 and 44 at. % have been studied. The samples were annealed at progressively higher temperatures and the newly formed phases were identified both after each annealing step by ex-situ conventional X-ray diffraction (XRD) and continuously by in-situ synchrotron XRD. It was found that Si was the only phase to form in a sample with 20 at.% P since the evaporation of P at the crystallization temperature prevented phosphides from forming. For a sample with 30at.% P, the Si{sub 12}P{sub 5} phase formed prior to the SiP phase. For samples with 35 and 44at.%P, the formation of SiP preceded the formation of the Si{sub 12}P{sub 5} phase. The experimentally determined phase formation sequences were successfully predicted by a proposed model. According to the model, the first and second crystalline phases to form are those with the lowest and next-lowest crystallization temperatures of the competing compounds predicted by the Gibbs free-energy diagram.

  1. Modeling of 1,3-hexadiene, 2,4-hexadiene and 1,4-hexadiene-doped methane flames: Flame modeling, benzene and styrene formation

    SciTech Connect (OSTI)

    Sharma, Sandeep; Harper, Michael R.; Green, William H.

    2010-07-15

    In this work, we have developed a detailed chemical kinetic model and reacting flow simulation for the hexadiene-doped 2-d methane diffusion flames studied experimentally by McEnally and Pfefferle. The GRI-Mech 2.11 methane oxidation and Lawrence Livermore butane oxidation mechanisms were used as the base mechanism to which hexadiene chemistry generated by Reaction Mechanism Generator (RMG) was added. Some important chemically activated pathways leading to aromatic species formation, including the reactions on C{sub 5}H{sub 7}, C{sub 6}H{sub 10}, C{sub 6}H{sub 9}, C{sub 6}H{sub 7}, C{sub 8}H{sub 8} and C{sub 8}H{sub 9} potential energy surfaces, are examined in great detail using quantum chemistry (CBS-QB3) and master equation analysis as implemented in Variflex. An efficient program to solve the doped methane diffusion flame was developed. The solver uses the method of lines to solve the species mass balance equation arising in the diffusion flame. It assumes that the temperature and velocity profiles of the doped flame are the same as those of the undoped flame. The mole fractions of various species as predicted by our model are compared to the experimentally measured mole fractions. The agreement between theory and experiments is quite good for most molecules. The added hexadiene dopants to the flame decompose to produce significant amount of cyclopentadienyl radical, which combines with methyl radical to produce benzene. We also show that styrene is formed primarily by recombination of cyclopentadienyl and propargyl radicals, a pathway which to our knowledge, has not been included in prior flame simulations. (author)

  2. Anthropogenic emissions of NOx over China: Reconciling the difference of inverse modeling results using GOME-2 and OMI measurements

    SciTech Connect (OSTI)

    Gu, Dasa; Wang, Yuhang; Smeltzer, Charles; Boersma, K. Folkert

    2014-06-27

    Inverse modeling using satellite observations of nitrogen dioxide (NO2) columns has been extensively used to estimate nitrogen oxides (NOx) emissions in China. Recently, the Global Ozone Monitoring Experiment-2 (GOME-2) and Ozone Monitoring Instrument (OMI) provide independent global NO2 column measurements on a nearly daily basis at around 9:30 and 13:30 local time across the equator, respectively. Anthropogenic NOx emission estimates by applying previously developed monthly inversion (MI) or daily inversion (DI) methods to these two sets of measurements show substantial differences. We improve the DI method by conducting model simulation, satellite retrieval, and inverse modeling sequentially on a daily basis. After each inversion, we update anthropogenic NOx emissions in the model simulation with the newly obtained a posteriori results. Consequently, the inversion-optimized emissions are used to compute the a priori NO2 profiles for satellite retrievals. As such, the a priori profiles used in satellite retrievals are now coupled to inverse modeling results. The improved procedure was applied to GOME-2 and OMI NO2 measurements in 2011. The new daily retrieval-inversion (DRI) method estimates an average NOx emission of 6.9 Tg N/yr over China, and the difference between using GOME-2 and OMI measurements is 0.4 Tg N/yr, which is significantly smaller than the difference of 1.3 Tg N/yr using the previous DI method. Using the more consistent DRI inversion results, we find that anthropogenic NOx emissions tend to be higher in winter and summer than spring (and possibly fall) and the weekday-to-weekend emission ratio tends to increase with NOx emission in China.

  3. Modeling target bulk heating resulting from ultra-intense short pulse laser irradiation of solid density targets

    SciTech Connect (OSTI)

    Antici, P. [Dipartimento SBAI, Università di Roma ‘‘La Sapienza,’’ Via Scarpa 14-16, 00161 Roma (Italy) [Dipartimento SBAI, Università di Roma ‘‘La Sapienza,’’ Via Scarpa 14-16, 00161 Roma (Italy); INRS-EMT, Varennes, Québec (Canada); Istituto Nazionale di Fisica Nucleare, Via E. Fermi, 40-00044 Frascati (Italy); LULI, École Polytechnique, CNRS, CEA, UPMC, route de Saclay, 91128 Palaiseau (France); Gremillet, L. [CEA, DAM, DIF, F-91297 Arpajon (France)] [CEA, DAM, DIF, F-91297 Arpajon (France); Grismayer, T. [GoLP/Instituto de Plasmas e Fusão Nuclear-Laboratório Associado, Instituto Superior Técnico, 1049-001 Lisboa (Portugal)] [GoLP/Instituto de Plasmas e Fusão Nuclear-Laboratório Associado, Instituto Superior Técnico, 1049-001 Lisboa (Portugal); Mora, P. [Centre de Physique Théorique, École Polytechnique, CNRS, 91128 Palaiseau (France)] [Centre de Physique Théorique, École Polytechnique, CNRS, 91128 Palaiseau (France); Audebert, P.; Man?ic, A.; Fuchs, J. [LULI, École Polytechnique, CNRS, CEA, UPMC, route de Saclay, 91128 Palaiseau (France)] [LULI, École Polytechnique, CNRS, CEA, UPMC, route de Saclay, 91128 Palaiseau (France); Borghesi, M.; Cecchetti, C. A. [School of Mathematics and Physics, The Queen's University, Belfast (United Kingdom)] [School of Mathematics and Physics, The Queen's University, Belfast (United Kingdom)

    2013-12-15

    Isochoric heating of solid-density matter up to a few tens of eV is of interest for investigating astrophysical or inertial fusion scenarios. Such ultra-fast heating can be achieved via the energy deposition of short-pulse laser generated electrons. Here, we report on experimental measurements of this process by means of time- and space-resolved optical interferometry. Our results are found in reasonable agreement with a simple numerical model of fast electron-induced heating.

  4. Impact of a Revised Convective Triggering Mechanism on CAM2 Model Simulations: Results from Short-Range Weather Forecasts

    SciTech Connect (OSTI)

    Xie, S; Boyle, J S; Cederwall, R T; Potter, G L; Zhang, M; Lin, W

    2004-02-19

    This study implements a revised convective triggering condition in the National Center for Atmospheric Research (NCAR) Community Atmosphere Model (CAM2) model to reduce its excessive warm season daytime precipitation over land. The new triggering mechanism introduces a simple dynamic constraint on the initiation of convection that emulates the collective effects of lower level moistening and upward motion of the large-scale circulation. It requires a positive contribution from the large-scale advection of temperature and moisture to the existing positive Convective Available Potential Energy (CAPE) for model convection to start. In contrast, the original convection triggering function in CAM2 assumes that convection is triggered whenever there is positive CAPE, which results in too frequent warm season convection over land arising from strong diurnal variation of solar radiation. We examine the impact of the new trigger on CAM2 simulations by running the climate model in Numerical Weather Prediction (NWP) mode so that more available observations and high-frequency NWP analysis data can be used to evaluate model performance. We show that the modified triggering mechanism has led to considerable improvements in the simulation of precipitation, temperature, moisture, clouds, radiations, surface temperature, and surface sensible and latent heat fluxes when compared to the data collected from the Atmospheric Radiation Measurement (ARM) program at its South Great Plains (SGP) site. Similar improvements are also seen over other parts of the globe. In particular, the surface precipitation simulation has been significantly improved over both the continental United States and around the globe; the overestimation of high clouds in the equatorial tropics has been substantially reduced; and the temperature, moisture, and zonal wind are more realistically simulated. Results from this study also show that some systematic errors in the CAM2 climate simulations can be detected in the early stage of model integration. Examples are the extremely overestimated high clouds in the tropics in the vicinity of ITCZ and the spurious precipitation maximum in the east of the Rockies. This has important implications in studies of these model errors since running the climate model in NWP mode allows us to perform a more in-depth analysis during a short time period where more observations are available and different model errors from various processes have not compensated for the systematic errors.

  5. Introduction Central Limit Problem for inelastic Kac model Main results Beyond Kac's equation Speed of approach to equilibrium for an inelastic

    E-Print Network [OSTI]

    Bassetti, Federico

    Introduction Central Limit Problem for inelastic Kac model Main results Beyond Kac's equation Speed;Introduction Central Limit Problem for inelastic Kac model Main results Beyond Kac's equation Summary developments #12;Introduction Central Limit Problem for inelastic Kac model Main results Beyond Kac's equation

  6. Offshore Code Comparison Collaboration within IEA Wind Task 23: Phase IV Results Regarding Floating Wind Turbine Modeling; Preprint

    SciTech Connect (OSTI)

    Jonkman, J.; Larsen, T.; Hansen, A.; Nygaard, T.; Maus, K.; Karimirad, M.; Gao, Z.; Moan, T.; Fylling, I.

    2010-04-01

    Offshore wind turbines are designed and analyzed using comprehensive simulation codes that account for the coupled dynamics of the wind inflow, aerodynamics, elasticity, and controls of the turbine, along with the incident waves, sea current, hydrodynamics, and foundation dynamics of the support structure. This paper describes the latest findings of the code-to-code verification activities of the Offshore Code Comparison Collaboration, which operates under Subtask 2 of the International Energy Agency Wind Task 23. In the latest phase of the project, participants used an assortment of codes to model the coupled dynamic response of a 5-MW wind turbine installed on a floating spar buoy in 320 m of water. Code predictions were compared from load-case simulations selected to test different model features. The comparisons have resulted in a greater understanding of offshore floating wind turbine dynamics and modeling techniques, and better knowledge of the validity of various approximations. The lessons learned from this exercise have improved the participants' codes, thus improving the standard of offshore wind turbine modeling.

  7. Design and Analysis of a Test Rig for Modeling the Bit/Formation Interface in Petroleum Drilling Applications 

    E-Print Network [OSTI]

    Wilson, Joshua Kyle

    2013-04-11

    and horizontal wells and measuring the effects of various factors on the stability of perturbations on the system. A test rig concept has been developed to accurately measure the interaction forces and torques between the bit, formation and fluids during drilling...

  8. Sequestration of Dissolved CO2 in the Oriskany Formation

    SciTech Connect (OSTI)

    Dilmore, R.M.; Allen, D.E. (Salem State College, Salem, MA); McCarthy-Jones, J.R.; Hedges, S.W.; Soong, Yee

    2008-04-15

    Experiments were conducted to determine the solubility of CO2 in a natural brine solution of the Oriskany formation under elevated temperature and pressure conditions. These data were collected at temperatures of 22 and 75 °C and pressures between 100 and 450 bar. Experimentally determined data were compared with CO2 solubility predictions using a model developed by Duan and Sun (Chem. Geol. 2003, 193, 257-271). Model results compare well with Oriskany brine CO2 solubility data collected experimentally, suggesting that the Duan and Sun model is a reliable tool for estimating solution CO2 capacity in high salinity aquifers in the temperature and pressure range evaluated. The capacity for the Oriskany formation to sequester dissolved CO2 was calculated using results of the solubility models, estimation of the density of CO2 saturated brine, and available geographic information system (GIS) information on the formation depth and thickness. Results indicate that the Oriskany formation can hold approximately 0.36 gigatonnes of dissolved CO2 if the full basin is considered. When only the region where supercritical CO2 can exist (temperatures greater than 31° C and pressures greater than 74 bar) is considered, the capacity of the Oriskany formation to sequester dissolved CO2 is 0.31 gigatonnes. The capacity estimate considering the potential to sequester free-phase supercritical CO2 if brine were displaced from formation pore space is 8.8 gigatonnes in the Oriskany formation.

  9. Word formation in Thadou

    E-Print Network [OSTI]

    Haokip, Pauthang

    2014-01-01

    As stated above, compound words of Thadou are mostlyNote that the resulting new words are always nouns. a. b. c.bad’ (negative) Haokip: Word formation in Thadou a. â-sâa ?

  10. Testing models of ultra-fast India-Asia convergence : new paleomagnetic results from Ladakh, Western Himalaya

    E-Print Network [OSTI]

    Bailey, Elizabeth A

    2014-01-01

    Rapid India-Asia convergence has led to a major continental collision and formation of the Himalayas, the highest mountain range on Earth. Knowledge of the paleolatitude of the Kohistan-Ladakh Arc (KLA), an intermediate ...

  11. Steady state and dynamic modeling of a packed bed reactor for the partial oxidation of methanol to formaldehyde: experimental results compared with model predictions

    SciTech Connect (OSTI)

    Schwedock, M.J.; Windes, L.C.; Ray, W.H.

    1985-01-01

    Heterogeneous and pseudohomogeneous models are compared to experimental data from a packed bed reactor for the partical oxidation of methanol to formaldehyde over an iron oxide-molybdenum oxide catalyst. Heat transfer parameters which were successful in matching data from experiments without reaction were not successful in matching temperature data from experiments with reaction. This made it necessary to decrease the fluid radial heat transfer to obtain good fit. A good fit was obtained for steady state composition profiles by optimizing selected frequency factors and the activation energy for methanol. A redox rate expression for the oxidation of formaldehyde to carbon monoxide was proposed since a simple first-order rate expression did not fit the data. The pseudohomogeneous model gave results similar to the heterogeneous model for both steady state and dynamic experiments and has been recommended for future experimental state estimation and control studies. 21 refs., 31 figs., 6 tabs.

  12. The solar photospheric abundance of hafnium and thorium. Results from CO5BOLD 3D hydrodynamic model atmospheres

    E-Print Network [OSTI]

    Elisabetta Caffau; L. Sbordone; H. -G. Ludwig; P. Bonifacio; M. Steffen; N. T. Behara

    2008-03-25

    Context: The stable element hafnium (Hf) and the radioactive element thorium (Th) were recently suggested as a suitable pair for radioactive dating of stars. The applicability of this elemental pair needs to be established for stellar spectroscopy. Aims: We aim at a spectroscopic determination of the abundance of Hf and Th in the solar photosphere based on a \\cobold 3D hydrodynamical model atmosphere. We put this into a wider context by investigating 3D abundance corrections for a set of G- and F-type dwarfs. Method: High-resolution, high signal-to-noise solar spectra were compared to line synthesis calculations performed on a solar CO5BOLD model. For the other atmospheres, we compared synthetic spectra of CO5BOLD 3D and associated 1D models. Results: For Hf we find a photospheric abundance A(Hf)=0.87+-0.04, in good agreement with a previous analysis, based on 1D model atmospheres. The weak Th ii 401.9 nm line constitutes the only Th abundance indicator available in the solar spectrum. It lies in the red wing of an Ni-Fe blend exhibiting a non-negligible convective asymmetry. Accounting for the asymmetry-related additional absorption, we obtain A(Th)=0.09+-0.03, consistent with the meteoritic abundance, and about 0.1 dex lower than obtained in previous photospheric abundance determinations. Conclusions: Only for the second time, to our knowledge, has am non-negligible effect of convective line asymmetries on an abundance derivation been highlighted. Three-dimensional hydrodynamical simulations should be employed to measure Th abundances in dwarfs if similar blending is present, as in the solar case. In contrast, 3D effects on Hf abundances are small in G- to mid F-type dwarfs and sub-giants, and 1D model atmospheres can be conveniently used.

  13. Photoelectric heating and [CII] cooling in translucent clouds: results for cloud models based on simulations of compressible MHD turbulence

    E-Print Network [OSTI]

    M. Juvela; P. Padoan; R. Jimenez

    2003-03-23

    The photoelectric heating is believed to be the main heating mechanism in cool HI clouds. The heating rate can be estimated through observations of the [CII] line emission, since this is the main coolant in regions where the photoelectric effect dominates the heating. Comparison of the [CII] emission with the far-infrared (FIR) emission allows to constrain the efficiency of the photoelectric heating, using model calculations that take into account the strength of the radiation field. Recent [CII] observations carried out with the ISO satellite have made this study possible. In this work we study the correlation between FUV absorption and FIR emission using three-dimensional models. The density distributions are obtained with numerical simulations of compressible magneto-hydrodynamic turbulence, with rms sonic Mach numbers 0.6models, implying that the derived values of epsilon should not depend on the rms Mach number. The comparison with empirical data from translucent, high latitude clouds yields an estimate of the photoelectric heating efficiency of 2.9 10^-2. This value confirms previous theoretical predictions. Our models show that most of the scatter in the observed [CII] and FIR intensities can be understood as a result of the highly fragmented density field in turbulent HI clouds. The scatter can be reproduced with models with supersonic turbulence, while subsonic turbulence fails to generate the observed scatter.

  14. Some exact results for the zero-bandwidth extended Hubbard model with intersite charge and magnetic interactions

    E-Print Network [OSTI]

    Konrad Jerzy Kapcia; Waldemar K?obus; Stanis?aw Robaszkiewicz

    2015-05-13

    The extended Hubbard model in the zero-bandwidth limit is studied. The effective Hamiltonian consists of (i) on-site $U$ interaction and intersite (ii) density-density interaction $W$ and (iii) Ising-like magnetic exchange interaction $J$ (between the nearest-neighbors). We present rigorous (and analytical) results obtained within the transfer-matrix method for 1D-chain in two particular cases: (a) $W=0$ and $n=1$; (b) $U\\rightarrow+\\infty$ and $n=1/2$ ($W\

  15. Motivation and model Gibbs sampler and EM setup Results for simulated and real data Challenges with Gibbs sampler Accounting for missing lines in atomic

    E-Print Network [OSTI]

    Wolfe, Patrick J.

    Motivation and model Gibbs sampler and EM setup Results for simulated and real data Challenges University 1 Dec, 2009 #12;Motivation and model Gibbs sampler and EM setup Results for simulated and real to identify lines that were omitted in the atomic emission table. #12;Motivation and model Gibbs sampler

  16. A stochastic model and Monte Carlo algorithm for fluctuation-induced H$_2$ formation on the surface of interstellar dust grains

    E-Print Network [OSTI]

    Sabelfeld, Karl

    2015-01-01

    A stochastic algorithm for simulation of fluctuation-induced kinetics of H$_2$ formation on grain surfaces is suggested as a generalization of the technique developed in our recent studies where this method was developed to describe the annihilation of spatially separate electrons and holes in a disordered semiconductor. The stochastic model is based on the spatially inhomogeneous, nonlinear integro-differential Smoluchowski equations with random source term. In this paper we derive the general system of Smoluchowski type equations for the formation of H$_2$ from two hydrogen atoms on the surface of interstellar dust grains with physisorption and chemisorption sites. We focus in this study on the spatial distribution, and numerically investigate the segregation in the case of a source with a continuous generation in time and randomly distributed in space. The stochastic particle method presented is based on a probabilistic interpretation of the underlying process as a stochastic Markov process of interacting ...

  17. Shock-Wave Heating Model for Chondrule Formation: Hydrodynamic Simulation of Molten Droplets exposed to Gas Flows

    E-Print Network [OSTI]

    Hitoshi Miura; Taishi Nakamoto

    2006-11-09

    Millimeter-sized, spherical silicate grains abundant in chondritic meteorites, which are called as chondrules, are considered to be a strong evidence of the melting event of the dust particles in the protoplanetary disk. One of the most plausible scenarios is that the chondrule precursor dust particles are heated and melt in the high-velocity gas flow (shock-wave heating model). We developed the non-linear, time-dependent, and three-dimensional hydrodynamic simulation code for analyzing the dynamics of molten droplets exposed to the gas flow. We confirmed that our simulation results showed a good agreement in a linear regime with the linear solution analytically derived by Sekiya et al. (2003). We found that the non-linear terms in the hydrodynamical equations neglected by Sekiya et al. (2003) can cause the cavitation by producing negative pressure in the droplets. We discussed that the fragmentation through the cavitation is a new mechanism to determine the upper limit of chondrule sizes. We also succeeded to reproduce the fragmentation of droplets when the gas ram pressure is stronger than the effect of the surface tension. Finally, we compared the deformation of droplets in the shock-wave heating with the measured data of chondrules and suggested the importance of other effects to deform droplets, for example, the rotation of droplets. We believe that our new code is a very powerful tool to investigate the hydrodynamics of molten droplets in the framework of the shock-wave heating model and has many potentials to be applied to various problems.

  18. A CRITICAL EXAMINATION OF THE X-WIND MODEL FOR CHONDRULE AND CALCIUM-RICH, ALUMINUM-RICH INCLUSION FORMATION AND RADIONUCLIDE PRODUCTION

    SciTech Connect (OSTI)

    Desch, S. J.; Morris, M. A.; Connolly, H. C.; Boss, Alan P.

    2010-12-10

    Meteoritic data, especially regarding chondrules and calcium-rich, aluminum-rich inclusions (CAIs), and isotopic evidence for short-lived radionuclides (SLRs) in the solar nebula, potentially can constrain how planetary systems form. Interpretation of these data demands an astrophysical model, and the 'X-wind' model of Shu et al. and collaborators has been advanced to explain the origin of chondrules, CAIs, and SLRs. It posits that chondrules and CAIs were thermally processed <0.1 AU from the protostar, then flung by a magnetocentrifugal outflow to the 2-3 AU region to be incorporated into chondrites. Here we critically examine key assumptions and predictions of the X-wind model. We find a number of internal inconsistencies: theory and observation show no solid material exists at 0.1 AU; particles at 0.1 AU cannot escape being accreted into the star; particles at 0.1 AU will collide at speeds high enough to destroy them; thermal sputtering will prevent growth of particles; and launching of particles in magnetocentrifugal outflows is not modeled, and may not be possible. We also identify a number of incorrect predictions of the X-wind model: the oxygen fugacity where CAIs form is orders of magnitude too oxidizing, chondrule cooling rates are orders of magnitude lower than those experienced by barred olivine chondrules, chondrule-matrix complementarity is not predicted, and the SLRs are not produced in their observed proportions. We conclude that the X-wind model is not relevant to chondrule and CAI formation and SLR production. We discuss more plausible models for chondrule and CAI formation and SLR production.

  19. NSTX Disruption Simulations of Detailed Divertor and Passive Plate Models by Vector Potential Transfer from OPERA Global Analysis Results

    SciTech Connect (OSTI)

    P. H. Titus, S. Avasaralla, A.Brooks, R. Hatcher

    2010-09-22

    The National Spherical Torus Experiment (NSTX) project is planning upgrades to the toroidal field, plasma current and pulse length. This involves the replacement of the center-stack, including the inner legs of the TF, OH, and inner PF coils. A second neutral beam will also be added. The increased performance of the upgrade requires qualification of the remaining components including the vessel, passive plates, and divertor for higher disruption loads. The hardware needing qualification is more complex than is typically accessible by large scale electromagnetic (EM) simulations of the plasma disruptions. The usual method is to include simplified representations of components in the large EM models and attempt to extract forces to apply to more detailed models. This paper describes a more efficient approach of combining comprehensive modeling of the plasma and tokamak conducting structures, using the 2D OPERA code, with much more detailed treatment of individual components using ANSYS electromagnetic (EM) and mechanical analysis. This capture local eddy currents and resulting loads in complex details, and allows efficient non-linear, and dynamic structural analyses.

  20. Motivation Overview Automatic Segmentation Algorithm Building Colour Models Volumetric Graph-Cut Results Conclusion Automatic 3D Object Segmentation in Multiple

    E-Print Network [OSTI]

    Esteban, Carlos Hernández

    Motivation Overview Automatic Segmentation Algorithm Building Colour Models Volumetric Graph Segmentation in Multiple Views using Volumetric Graph-Cuts #12;Motivation Overview Automatic Segmentation Algorithm Building Colour Models Volumetric Graph-Cut Results Conclusion Motivation Neill Campbell, George

  1. Shock-Wave Heating Model for Chondrule Formation: Hydrodynamic Simulation of Molten Droplets exposed to Gas Flows

    E-Print Network [OSTI]

    Miura, H; Miura, Hitoshi; Nakamoto, Taishi

    2006-01-01

    Millimeter-sized, spherical silicate grains abundant in chondritic meteorites, which are called as chondrules, are considered to be a strong evidence of the melting event of the dust particles in the protoplanetary disk. One of the most plausible scenarios is that the chondrule precursor dust particles are heated and melt in the high-velocity gas flow (shock-wave heating model). We developed the non-linear, time-dependent, and three-dimensional hydrodynamic simulation code for analyzing the dynamics of molten droplets exposed to the gas flow. We confirmed that our simulation results showed a good agreement in a linear regime with the linear solution analytically derived by Sekiya et al. (2003). We found that the non-linear terms in the hydrodynamical equations neglected by Sekiya et al. (2003) can cause the cavitation by producing negative pressure in the droplets. We discussed that the fragmentation through the cavitation is a new mechanism to determine the upper limit of chondrule sizes. We also succeeded t...

  2. Atomic Level Green-Kubo Stress Correlation Function for a Model Crystal: An Insight into Molecular Dynamics Results on a Model Liquid

    E-Print Network [OSTI]

    V. A. Levashov

    2014-06-23

    In order to get insight into the connection between the vibrational dynamics and the atomic level Green-Kubo stress correlation function in liquids we consider this connection in a model crystal instead. Of course, vibrational dynamics in liquids and crystals are quite different and it is not expected that the results obtained on a model crystal should be valid for liquids. However, these considerations provide a benchmark to which the results of the previous molecular dynamics simulations can be compared. Thus, assuming that vibrations are plane waves, we derive analytical expressions for the atomic level stress correlation functions in the classical limit and analyze them. These results provide, in particular, a recipe for analysis of the atomic level stress correlation functions in Fourier space and extraction of the wavevector and frequency dependent information. We also evaluate the energies of the atomic level stresses. Obtained energies are significantly smaller than the energies that were obtained in MD simulations of liquids previously. This result suggests that the average energies of the atomic level stresses in liquids and glasses are largely determined by the structural disorder. We discuss this result in the context of equipartition of the atomic level stress energies. Analysis of the previously published data suggests that it is possible to speak about configurational and vibrational contributions to the average energies of the atomic level stresses in a glass state. However, this separation in a liquid state is problematic. We also consider peak broadening in the pair distribution function with increase of distance. We find that peak broadening (by ~40%) occurs due to the transverse vibrational modes, while contribution from the longitudinal modes does not change with distance. Finally, we introduce and consider atomic level transverse current correlation function.

  3. Methodology and results of the impacts of modeling electric utilities ; a comparative evaluation of MEMM and REM

    E-Print Network [OSTI]

    Baughman, Martin L.

    1981-01-01

    This study compares two models of the U.S. electric utility industry including the EIA's electric utility submodel in the Midterm Energy Market Model (MEMM), and the Baughman-Joskow Regionalized Electricity Model (REM). ...

  4. Glaciation and saline-freshwater mixing as a possible cause of cave formation in the eastern midcontinent region of the United States: A conceptual model

    SciTech Connect (OSTI)

    Panno, S.V. (Illinois State Geological Survey, Champaign (USA)); Bourcier, W.L. (Lawrence Livermore National Lab., CA (USA))

    1990-08-01

    We present a hypothesis for the formation of caves and associated karst features near the southern margins of the Illinois, Michigan, and Appalachian basins. Spatial and temporal relations among intracratonic basins, karstic terrain, and continental glaciation suggest that Pleistocene glaciation may have initiated the discharge of saline waters from the margins of these basins. Glaciation-induced discharge of saline waters could result from the consolidation of sediments due to the overlying pressure of glacial ice, and flushing of underlying aquifers as a result of bottom melting in recharge areas of basic aquifers. The upward migration of basin-derived saline waters into near-surface aquifers would result in the mixing of saline waters with infiltrating glacial meltwater and meteoric water. The development of a vertically restricted zone of mixing of saline and fresh water in limestone aquifers would result in the dissolution of limestone; this mechanism could be responsible for the formation, or at least the initiation of, some caves and associated karst features in the midcontinent region.

  5. A Comparison of HCCI Engine Performance Data and Kinetic Modeling Results over a Wide Rangeof Gasoline Range Surrogate Fuel Blends

    Broader source: Energy.gov [DOE]

    Kinetic models of fuels are needed to allow the simulation of engine performance for research, design, or verification purposes.

  6. Star Formation in Isolated Disk Galaxies. II. Schmidt Laws and Efficiency of Gravitational Collapse

    E-Print Network [OSTI]

    Yuexing Li; Mordecai-Mark Mac Low; Ralf S. Klessen

    2006-02-21

    (Abridged). We model gravitational instability in a wide range of isolated disk galaxies, using GADGET, a three-dimensional, smoothed particle hydrodynamics code. The model galaxies include a dark matter halo and a disk of stars and isothermal gas. The global Schmidt law observed in disk galaxies is quantitatively reproduced by our models. We find that the surface density of star formation rate directly correlates with the strength of local gravitational instability. The local Schmidt laws of individual galaxies in our models show clear evidence of star formation thresholds. Our results suggest that the non-linear development of gravitational instability determines the local and global Schmidt laws, and the star formation thresholds.

  7. Spontaneous Group Formation in the Seceder Model Peter Dittrich 1 , Fredrik Liljeros 2 , Arne Soulier 3 , and Wolfgang Banzhaf 1

    E-Print Network [OSTI]

    Dittrich, Peter

    . of Physics, New York, NY 10027 (Submitted: November 10, 1999; Shortened: February 25, 2000; Compiled energy functions [2,3], spatially separated populations [5,13] or sexual recombination [2's behavior and, then choose the most unique alternative. In this way, the model could be used

  8. A team of researchers is modeling ozone formation induced by volatile organic NORTHWESTERN CHEMICAL AND BIOLOGICAL ENGINEERING

    E-Print Network [OSTI]

    Ottino, Julio M.

    mechanistic models based on kinetics and photochemistry, from which predictions of ozone production can of data (products and reactions) using graph theory representations of species and a computer. Based. A simple 4 x 4 matrix represents formaldehyde. The diagonal elements and off- diagonal elements represent

  9. The Formation of Primordial Luminous Objects

    E-Print Network [OSTI]

    Emanuele Ripamonti; Tom Abel

    2005-07-06

    In these lecture notes we review the current knowledge about the formation of the first luminous objects. We start from the cosmological context of hierarchical models of structure formation, and discuss the main physical processes which are believed to lead to primordial star formation, i.e. the cooling processes and the chemistry of molecules (especially H2) in a metal-free gas. We then describe the techniques and results of numerical simulations, which indicate that the masses of the first luminous objects are likely to be much larger than that of present-day stars. Finally, we discuss the scenario presented above, exposing some of the most interesting problems which are currently being investigated, such as that of the feedback effects of these objects.

  10. Naked Singularity formation in scalar field collapse

    E-Print Network [OSTI]

    Rituparno Goswami; Pankaj S Joshi

    2004-10-28

    We construct here a class of collapsing scalar field models with a non-zero potential, which result in a naked singularity as collapse end state. The weak energy condition is satisfied by the collapsing configuration. It is shown that physically it is the rate of collapse that governs either the black hole or naked singularity formation as the final state for the dynamical evolution. It is seen that the cosmic censorship is violated in dynamical scalar field collapse.

  11. Modeling Mud-Filtrate Invasion Effects on Resistivity Logs to Estimate Permeability of Vuggy and Fractured Carbonate Formations

    E-Print Network [OSTI]

    Torres-Verdín, Carlos

    properties, we simulate the process of invasion with both water- and oil-base muds. Resulting spatial distributions of water saturation and salt concentration in the near-borehole region give rise to spatial

  12. Actualistic and Geochemical Modeling of Reservoir Rock, CO2 and Formation Fluid Interaction, Citronelle Oil Field, Alabama

    SciTech Connect (OSTI)

    Weislogel, Amy

    2014-01-31

    This report includes description of the Citronelle field study area and the work carried out in the project to characterize the geology and composition of reservoir rock material and to collect an analyze the geochemical composition of produced fluid waters from the Citronelle field. Reservoir rock samples collected from well bore core were made into thin-sections and assessed for textural properties, including pore types and porosity distribution. Compositional framework grain modal data were collected via point-counting, and grain and cement mineralogy was assessed using SEM-EDS. Geochemistry of fluid samples is described and modeled using PHREEQC. Composition of rock and produced fluids were used as inputs for TOUGHREACT reactive transport modeling, which determined the rock-fluid system was in disequilibrium.

  13. Mixed-mode diesel HCCI with External Mixture Formation: Preliminary...

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

    Mixed-mode diesel HCCI with External Mixture Formation: Preliminary Results Mixed-mode diesel HCCI with External Mixture Formation: Preliminary Results 2003 DEER Conference...

  14. Proportional structural effects of formative indicators

    E-Print Network [OSTI]

    Franke, George R.; Preacher, Kristopher J.; Rigdon, Ed E.

    2009-03-15

    that are proportional to their effects on the formative construct itself. This constraint has important implications for developing and testing formative models. This study demonstrates the existence of the constraint, shows that researchers must consider...

  15. Carbon-nitrogen interactions regulate climate-carbon cycle feedbacks: results from an atmosphere-ocean general circulation model

    E-Print Network [OSTI]

    Thornton, P. E.; Doney, S. C.; Lindsay, Keith; Moore, J. K.; Mahowald, N. M.; Randerson, J. T.; Fung, I.; Lamarque, J. F.; Feddema, Johannes J.

    2009-01-01

    Abstract. Inclusion of fundamental ecological interactions between carbon and nitrogen cycles in the land component of an atmosphere-ocean general circulation model (AOGCM) leads to decreased carbon uptake associated ...

  16. Formative time of breakdown modeled for the ignition of air and n-butane mixtures using effective ionization coefficients

    SciTech Connect (OSTI)

    Kudryavtsev, A. A.; Popugaev, S. D.; Demidov, V. I.; Adams, S. F.; Jiao, C. Q.

    2008-12-15

    It is shown that simulations of ignition by electric arc discharge in n-butane and air mixtures have interesting features, which deviate from results obtained by simple extension of calculations based on methanelike fuels. In particular, it is demonstrated that lowering the temperature of the n-butane-air mixture before ignition under certain conditions will actually decrease the ignition stage time as well as the required electric field.

  17. 2D MHD and 1D HD models of a solar flare -- a comprehensive comparison of the results

    E-Print Network [OSTI]

    Falewicz, R; Murawski, K; Srivastava, A K

    2015-01-01

    Without any doubt solar flaring loops possess a multi-thread internal structure that is poorly resolved and there are no means to observe heating episodes and thermodynamic evolution of the individual threads. These limitations cause fundamental problems in numerical modelling of flaring loops, such as selection of a structure and a number of threads, and an implementation of a proper model of the energy deposition process. A set of 1D hydrodynamic and 2D magnetohydrodynamic models of a flaring loop are developed to compare energy redistribution and plasma dynamics in the course of a prototypical solar flare. Basic parameters of the modeled loop are set according to the progenitor M1.8 flare recorded in the AR10126 on September 20, 2002 between 09:21 UT and 09:50 UT. The non-ideal 1D models include thermal conduction and radiative losses of the optically thin plasma as energy loss mechanisms, while the non-ideal 2D models take into account viscosity and thermal conduction as energy loss mechanisms only. The 2...

  18. Deformed shell model results for neutrinoless double beta decay of nuclei in A=60-90 region

    E-Print Network [OSTI]

    R. Sahu; V. K. B. Kota

    2015-03-20

    Nuclear transition matrix elements (NTME) for the neutrinoless double beta decay of $^{70}$Zn, $^{80}$Se and $^{82}$Se nuclei are calculated within the framework of the deformed shell model based on Hartree-Fock states. For $^{70}$Zn, jj44b interaction in $^{2}p_{3/2}$, $^{1}f_{5/2}$, $^{2}p_{1/2}$ and $^{1}g_{9/2}$ space with $^{56}$Ni as the core is employed. However, for $^{80}$Se and $^{82}$Se nuclei, a modified Kuo interaction with the above core and model space are employed. Most of our calculations in this region were performed with this effective interaction. However, jj44b interaction has been found to be better for $^{70}$Zn. The above model space was used in many recent shell model and interacting boson model calculations for nuclei in this region. After ensuring that DSM gives good description of the spectroscopic properties of low-lying levels in these three nuclei considered, the NTME are calculated. The deduced half-lives with these NTME, assuming neutrino mass is 1 eV, are $1.1 \\times 10^{26}$ yr, $2.3 \\times 10^{27}$ yr and $2.2 \\times 10^{24}$ yr for $^{70}$Zn, $^{80}$Se and $^{82}$Se, respectively.

  19. Carbon-nitrogen interactions regulate climate-carbon cycle feedbacks: results from an atmosphere-ocean general circulation model

    E-Print Network [OSTI]

    2009-01-01

    2009 P. E. Thornton et al. : Carbon-nitrogen interactionsregulate climate-carbon cycle feedbacks Monfray, P. ,T. H. : A global ocean carbon climatology: Results from

  20. The small and the beautiful: How the star formation law affects galactic disk structure

    E-Print Network [OSTI]

    Braun, Harald

    2015-01-01

    We investigate the influence of different analytical parameterizations and fit functions for the local star formation rate in AMR simulations of an isolated disk galaxy with the Nyx code. Such parameterizations express the star formation efficiency as function of the local turbulent Mach number and viral parameter. By employing the method of adaptively refined large eddy simulations, we are able to evaluate these physical parameters from the numerically unresolved turbulent energy associated with the grid scale. We consider both single and multi free-fall variants of star formation laws proposed by Padoan & Nordlund, Hennebelle & Chabrier, and Krumholz & McKee. We find that the global star formation rate and the relation between the local star formation rate and the gas column density is reproduced in agreement with observational constraints by all multi free-fall models of star formation. Some models with obsolete calibration or a single free-fall time scale, however, result in an overly clumpy d...

  1. The initial conditions of high-mass star formation: radiative transfer models of IRDCs seen in the Herschel Hi-GAL survey

    E-Print Network [OSTI]

    Wilcock, L A; Stamatellos, D; Ward-Thompson, D; Whitworth, A; Battersby, C; Brunt, C; Fuller, G A; Griffin, M; Molinari, S; Martin, P; Mottram, J C; Peretto, N; Plume, R; Smith, H A; Thompson, M A; 10.1051/0004-6361/201015488

    2011-01-01

    The densest infrared dark clouds (IRDCs) may represent the earliest observable stage of high-mass star formation. These clouds are very cold, hence they emit mainly at far-infrared and sub-mm wavelengths. For the first time, Herschel has provided multi-wavelength, spatially resolved observations of cores within IRDCs, which, when combined with radiative transfer modelling, can constrain their properties, such as mass, density profile and dust temperature. We use a 3D, multi-wavelength Monte Carlo radiative transfer code to model in detail the emission from six cores in three typical IRDCs seen in the Hi-GAL survey (G030.50+00.95, G031.03+00.26 and G031.03+00.76), and thereby to determine the properties of these cores and compare them with their low-mass equivalents. We found masses ranging from 90 to 290 solar masses with temperatures from 8 to 11K at the centre of each core and 18 to 28K at the surface. The maximum luminosity of an embedded star within each core was calculated, and we rule out the possibilit...

  2. Reconstructing the Star Formation Histories of Galaxies

    E-Print Network [OSTI]

    Uta Fritze; Thomas Lilly

    2007-01-15

    We present a methodological study to find out how far back and to what precision star formation histories of galaxies can be reconstructed from CMDs, from integrated spectra and Lick indices, and from integrated multi-band photometry. Our evolutionary synthesis models GALEV allow to describe the evolution of galaxies in terms of all three approaches and we have assumed typical observational uncertainties for each of them and then investigated to what extent and accuracy different star formation histories can be discriminated. For a field in the LMC bar region with both a deep CMD from HST observations and a trailing slit spectrum across exactly the same field of view we could test our modelling results against real data.

  3. Determination of High-Frequency Current Distribution Using EMTP-Based Transmission Line Models with Resulting Radiated Electromagnetic Fields

    SciTech Connect (OSTI)

    Mork, B; Nelson, R; Kirkendall, B; Stenvig, N

    2009-11-30

    Application of BPL technologies to existing overhead high-voltage power lines would benefit greatly from improved simulation tools capable of predicting performance - such as the electromagnetic fields radiated from such lines. Existing EMTP-based frequency-dependent line models are attractive since their parameters are derived from physical design dimensions which are easily obtained. However, to calculate the radiated electromagnetic fields, detailed current distributions need to be determined. This paper presents a method of using EMTP line models to determine the current distribution on the lines, as well as a technique for using these current distributions to determine the radiated electromagnetic fields.

  4. SISGR - In situ characterization and modeling of formation reactions under extreme heating rates in nanostructured multilayer foils

    SciTech Connect (OSTI)

    Hufnagel, Todd C.

    2014-06-09

    Materials subjected to extreme conditions, such as very rapid heating, behave differently than materials under more ordinary conditions. In this program we examined the effect of rapid heating on solid-state chemical reactions in metallic materials. One primary goal was to develop experimental techniques capable of observing these reactions, which can occur at heating rates in excess of one million degrees Celsius per second. One approach that we used is x-ray diffraction performed using microfocused x-ray beams and very fast x-ray detectors. A second approach is the use of a pulsed electron source for dynamic transmission electron microscopy. With these techniques we were able to observe how the heating rate affects the chemical reaction, from which we were able to discern general principles about how these reactions proceed. A second thrust of this program was to develop computational tools to help us understand and predict the reactions. From atomic-scale simulations were learned about the interdiffusion between different metals at high heating rates, and about how new crystalline phases form. A second class of computational models allow us to predict the shape of the reaction front that occurs in these materials, and to connect our understanding of interdiffusion from the atomistic simulations to measurements made in the laboratory. Both the experimental and computational techniques developed in this program are expected to be broadly applicable to a wider range of scientific problems than the intermetallic solid-state reactions studied here. For example, we have already begun using the x-ray techniques to study how materials respond to mechanical deformation at very high rates.

  5. ON THE DYNAMICS OF THE SOLAR CORONA: FIRST RESULTS OBTAINED WITH A NEW 3D MHD MODEL

    E-Print Network [OSTI]

    Grauer, Rainer

    of equations for a two- uid description of the solar wind plasma and point out possible numerical diÆculties arising from an improper choice of variables. Second, we perform a study of the solar wind expansion mass ejections and/or shocks. Key words: solar wind; MHD; numerical simulation; two- uid modeling

  6. Flow Sensing for Height Estimation and Control of a Rotor in Ground Effect: Modeling and Experimental Results

    E-Print Network [OSTI]

    Shapiro, Benjamin

    are presented and the effect of motor dynamics on the overall dynamics are investigated. Flowfield velocity the helicopter aerodynamics onboard and modulates the motor torque, rather than the collective pitch, during take- niques often require a system model with empirically fit aero- dynamic coefficients that are unique

  7. Assessment of effectiveness of geologic isolation systems. Geologic-simulation model for a hypothetical site in the Columbia Plateau. Volume 2: results

    SciTech Connect (OSTI)

    Foley, M.G.; Petrie, G.M.; Baldwin, A.J.; Craig, R.G.

    1982-06-01

    This report contains the input data and computer results for the Geologic Simulation Model. This model is described in detail in the following report: Petrie, G.M., et. al. 1981. Geologic Simulation Model for a Hypothetical Site in the Columbia Plateau, Pacific Northwest Laboratory, Richland, Washington. The Geologic Simulation Model is a quasi-deterministic process-response model which simulates, for a million years into the future, the development of the geologic and hydrologic systems of the ground-water basin containing the Pasco Basin. Effects of natural processes on the ground-water hydrologic system are modeled principally by rate equations. The combined effects and synergistic interactions of different processes are approximated by linear superposition of their effects during discrete time intervals in a stepwise-integration approach.

  8. Method of fracturing a geological formation

    DOE Patents [OSTI]

    Johnson, James O. (2679-B Walnut, Los Alamos, NM 87544)

    1990-01-01

    An improved method of fracturing a geological formation surrounding a well bore is disclosed. A relatively small explosive charge is emplaced in a well bore and the bore is subsequently hydraulically pressurized to a pressure less than the formation breakdown pressure and preferably greater than the fracture propagation pressure of the formation. The charge is denoted while the bore is so pressurized, resulting in the formation of multiple fractures in the surrounding formation with little or no accompanying formation damage. Subsequent hydraulic pressurization can be used to propagate and extend the fractures in a conventional manner. The method is useful for stimulating production of oil, gas and possibly water from suitable geologic formations.

  9. RAPID DUST FORMATION IN NOVAE: THE SPEED CLASS—FORMATION TIMESCALE CORRELATION EXPLAINED

    SciTech Connect (OSTI)

    Williams, S. C.; Bode, M. F.; Darnley, M. J.; Evans, A.; Zubko, V.; Shafter, A. W.

    2013-11-10

    Observations show that the time of onset of dust formation in classical novae depends strongly on their speed class, with dust typically taking longer to form in slower novae. Using empirical relationships between speed class, luminosity and ejection velocity, it can be shown that dust formation timescale is expected to be essentially independent of speed class. However, following a nova outburst the spectrum of the central hot source evolves, with an increasing proportion of the radiation being emitted short-ward of the Lyman limit. The rate at which the spectrum evolves also depends on the speed class. We have therefore refined the simple model by assuming photons at energies higher than the Lyman limit are absorbed by neutral hydrogen gas internal to the dust formation sites, therefore preventing these photons reaching the nucleation sites. With this refinement the dust formation timescale is theoretically dependent on speed class and the results of our theoretical modification agree well with the observational data. We consider two types of carbon-based dust, graphite and amorphous carbon, with both types producing similar relationships. Our results can be used to predict when dust will form in a nova of a given speed class and hence when observations should optimally be taken to detect the onset of dust formation.

  10. Physical control oriented model of large scale refrigerators to synthesize advanced control schemes. Design, validation, and first control results

    SciTech Connect (OSTI)

    Bonne, François; Bonnay, Patrick [INAC, SBT, UMR-E 9004 CEA/UJF-Grenoble, 17 rue des Martyrs, 38054 Grenoble (France); Alamir, Mazen [Gipsa-Lab, Control Systems Department, CNRS-University of Grenoble, 11, rue des Mathématiques, BP 46, 38402 Saint Martin d'Hères (France)

    2014-01-29

    In this paper, a physical method to obtain control-oriented dynamical models of large scale cryogenic refrigerators is proposed, in order to synthesize model-based advanced control schemes. These schemes aim to replace classical user experience designed approaches usually based on many independent PI controllers. This is particularly useful in the case where cryoplants are submitted to large pulsed thermal loads, expected to take place in the cryogenic cooling systems of future fusion reactors such as the International Thermonuclear Experimental Reactor (ITER) or the Japan Torus-60 Super Advanced Fusion Experiment (JT-60SA). Advanced control schemes lead to a better perturbation immunity and rejection, to offer a safer utilization of cryoplants. The paper gives details on how basic components used in the field of large scale helium refrigeration (especially those present on the 400W @1.8K helium test facility at CEA-Grenoble) are modeled and assembled to obtain the complete dynamic description of controllable subsystems of the refrigerator (controllable subsystems are namely the Joule-Thompson Cycle, the Brayton Cycle, the Liquid Nitrogen Precooling Unit and the Warm Compression Station). The complete 400W @1.8K (in the 400W @4.4K configuration) helium test facility model is then validated against experimental data and the optimal control of both the Joule-Thompson valve and the turbine valve is proposed, to stabilize the plant under highly variable thermals loads. This work is partially supported through the European Fusion Development Agreement (EFDA) Goal Oriented Training Program, task agreement WP10-GOT-GIRO.

  11. Model-Independent Results for the Decay B \\to L Nu(L) Gamma at BaBar

    SciTech Connect (OSTI)

    Lindemann, D.M.; /McGill U.

    2012-04-09

    We present a search for the radiative leptonic decays B{sub +} {yields} e{sup +} {nu}{sub e}{gamma} and B{sup +} {yields} {mu}{sup +}{nu}{sub {mu}}{gamma} using data collected by the BABAR detector at the PEP-II B factory. We fully reconstruct the hadronic decay of one of the B mesons in {Upsilon}(4S) {yields} B{sup +}B{sup -} and then search for evidence of the signal decay within the rest of the event. This method provides clean kinematic information on the signal's missing energy and high momentum photon and lepton, and allows for a model-independent analysis of this decay. Using a data sample of 465 million B-meson pairs, we obtain sensitivity to branching fractions of the same order as predicted by the Standard Model. We report a model-independent branching fraction upper limit of {Beta}(B{sup +} {yields} {ell}{sup +}{nu}{sub {ell}}{gamma}) < 15.6 x 10{sup -6} ({ell} = e or {mu}) at the 90% confidence level.

  12. The Mechanism of First Raindrops Formation in Deep Convective Clouds

    SciTech Connect (OSTI)

    Khain, Alexander; Prabha, Thara; Benmoshe, Nir; Pandithurai, G.; Ovchinnikov, Mikhail

    2013-08-22

    The formation of first raindrops in deep convective clouds is investigated. A combination of observational data analysis and 2-D and 3-D numerical bin microphysical simulations of deep convective clouds suggests that the first raindrops form at the top of undiluted or slightly diluted cores. It is shown that droplet size distributions in these regions are wider and contain more large droplets than in diluted volumes. The results of the study indicate that the initial raindrop formation is determined by the basic microphysical processes within ascending adiabatic volumes. It allows one to predict the height of the formation of first raindrops considering the processes of nucleation, diffusion growth and collisions. The results obtained in the study explain observational results reported by Freud and Rosenfeld (2012) according to which the height of first raindrop formation depends linearly on the droplet number concentration at cloud base. The results also explain why a simple adiabatic parcel model can reproduce this dependence. The present study provides a physical basis for retrieval algorithms of cloud microphysical properties and aerosol properties using satellites proposed by Rosenfeld et al. ( 2012). The study indicates that the role of mixing and entrainment in the formation of the first raindrops is not of crucial importance. It is also shown that low variability of effective and mean volume radii along horizontal traverses, as regularly observed by in situ measurements, can be simulated by high-resolution cloud models, in which mixing is parameterized by a traditional 1.5 order turbulence closure scheme.

  13. Isolating Triggered Star Formation

    E-Print Network [OSTI]

    Elizabeth J. Barton; Jacob A. Arnold; Andrew R. Zentner; James S. Bullock; Risa H. Wechsler

    2007-08-21

    Galaxy pairs provide a potentially powerful means of studying triggered star formation from galaxy interactions. We use a large cosmological N-body simulation coupled with a well-tested semi-analytic substructure model to demonstrate that the majority of galaxies in close pairs reside within cluster or group-size halos and therefore represent a biased population, poorly suited for direct comparison to ``field'' galaxies. Thus, the frequent observation that some types of galaxies in pairs have redder colors than ``field'' galaxies is primarily a selection effect. We select galaxy pairs that are isolated in their dark matter halos with respect to other massive subhalos (N=2 halos) and a control sample of isolated galaxies (N=1 halos) for comparison. We then apply these selection criteria to a volume-limited subset of the 2dF Galaxy Redshift Survey with M_Bj ~ 5 above their average past value, while only 10% of isolated galaxies in the control sample show this level of enhancement. Thus, 14% (20 %) of the galaxies in these close pairs show clear triggered star formation. The isolation criteria we develop provide a means to constrain star formation and feedback prescriptions in hydrodynamic simulations and a very general method of understanding the importance of triggered star formation in a cosmological context. (Abridged.)

  14. Final Report: Mechanisms of sputter ripple formation: coupling among energetic ions, surface kinetics, stress and composition

    SciTech Connect (OSTI)

    Chason, Eric; Shenoy, Vivek

    2013-01-22

    Self-organized pattern formation enables the creation of nanoscale surface structures over large areas based on fundamental physical processes rather than an applied template. Low energy ion bombardment is one such method that induces the spontaneous formation of a wide variety of interesting morphological features (e.g., sputter ripples and/or quantum dots). This program focused on the processes controlling sputter ripple formation and the kinetics controlling the evolution of surfaces and nanostructures in high flux environments. This was done by using systematic, quantitative experiments to measure ripple formation under a variety of processing conditions coupled with modeling to interpret the results.

  15. Introduction Linear theory Nonlinear theory Numerical results Closure Thermal shock waves under a MaxwellCattaneo model

    E-Print Network [OSTI]

    Christov, Ivan C.

    -Champaign, Illinois June 3, 2009 * Travel funding from the organizers is kindly acknowledged. Ivan Christov (NU Rankine­Hugoniot jump conditions for the nonlinear equations, nonlinear shock speed and an ad-hoc solution-dependent conductivity. 2 Solution of the linearized equations, singular surface theory results. 3 Rankine­Hugoniot jump

  16. Multi-century Changes to Global Climate and Carbon Cycle: Results from a Coupled Climate and Carbon Cycle Model

    SciTech Connect (OSTI)

    Bala, G; Caldeira, K; Mirin, A; Wickett, M; Delire, C

    2005-02-17

    In this paper, we use a coupled climate and carbon cycle model to investigate the global climate and carbon cycle changes out to year 2300 that would occur if CO{sub 2} emissions from all the currently estimated fossil fuel resources were released to the atmosphere. By year 2300, the global climate warms by about 8 K and atmospheric CO{sub 2} reaches 1423 ppmv. The warming is higher than anticipated because the sensitivity to radiative forcing increases as the simulation progresses. In our simulation, the rate of emissions peak at over 30 PgC yr{sup -1} early in the 22nd century. Even at year 2300, nearly 50% of cumulative emissions remain in the atmosphere. In our simulations both soils and living biomass are net carbon sinks throughout the simulation. Despite having relatively low climate sensitivity and strong carbon uptake by the land biosphere, our model projections suggest severe long-term consequences for global climate if all the fossil-fuel carbon is ultimately released to the atmosphere.

  17. Chemical composition analysis and product consistency tests to support enhanced Hanford waste glass models: Results for the January, March, and April 2015 LAW glasses

    SciTech Connect (OSTI)

    Fox, K. M.; Edwards, T. B.; Riley, W. T.; Best, D. R.

    2015-09-03

    In this report, the Savannah River National Laboratory provides chemical analyses and Product Consistency Test (PCT) results for several simulated low activity waste (LAW) glasses (designated as the January, March, and April 2015 LAW glasses) fabricated by the Pacific Northwest National Laboratory. The results of these analyses will be used as part of efforts to revise or extend the validation regions of the current Hanford Waste Treatment and Immobilization Plant glass property models to cover a broader span of waste compositions.

  18. Chemical composition analysis and product consistency tests to support Enhanced Hanford Waste Glass Models. Results for the Augusta and October 2014 LAW Glasses

    SciTech Connect (OSTI)

    Fox, K. M.; Edwards, T. B.; Best, D. R.

    2015-07-07

    In this report, the Savannah River National Laboratory provides chemical analyses and Product Consistency Test (PCT) results for several simulated low activity waste (LAW) glasses (designated as the August and October 2014 LAW glasses) fabricated by the Pacific Northwest National Laboratory. The results of these analyses will be used as part of efforts to revise or extend the validation regions of the current Hanford Waste Treatment and Immobilization Plant glass property models to cover a broader span of waste compositions.

  19. Mechanisms regulating the large-scale seasonal fluctuations in Alexandrium fundyense populations in the Gulf of Maine: results from a physical-biological model

    E-Print Network [OSTI]

    in the Gulf of Maine: results from a physical-biological model D.J. McGillicuddy, Jr.1 , D.M. Anderson1 D Ecology and Oceanography of Harmful Algal Blooms in the Gulf of Maine December 22, 2004 1 Woods Hole of Marine Sciences, University of Maine, Orono, ME 04469, USA. #12;2 Abstract Observations of Alexandrium

  20. Numerical modeling of carbon dioxide sequestration on the rate of pressure solution creep in limestone: Preliminary results

    E-Print Network [OSTI]

    Renard, Francois; Hellmann, Roland; Collombet, Marielle; Guen, Yvi Le

    2008-01-01

    When carbon dioxide (CO2) is injected into an aquifer or a depleted geological reservoir, its dissolution into solution results in acidification of the pore waters. As a consequence, the pore waters become more reactive, which leads to enhanced dissolution-precipitation processes and a modification of the mechanical and hydrological properties of the rock. This effect is especially important for limestones given that the solubility and reactivity of carbonates is strongly dependent on pH and the partial pressure of CO2. The main mechanism that couples dissolution, precipitation and rock matrix deformation is commonly referred to as intergranular pressure solution creep (IPS) or pervasive pressure solution creep (PSC). This process involves dissolution at intergranular grain contacts subject to elevated stress, diffusion of dissolved material in an intergranular fluid, and precipitation in pore spaces subject to lower stress. This leads to an overall and pervasive reduction in porosity due to both grain indent...

  1. INTEGRATED GEOLOGIC-ENGINEERING MODEL FOR REEF AND CARBONATE SHOAL RESERVOIRS ASSOCIATED WITH PALEOHIGHS: UPPER JURASSIC SMACKOVER FORMATION, NORTHEASTERN GULF OF MEXICO

    SciTech Connect (OSTI)

    Ernest A. Mancini

    2003-09-25

    The University of Alabama in cooperation with Texas A&M University, McGill University, Longleaf Energy Group, Strago Petroleum Corporation, and Paramount Petroleum Company are undertaking an integrated, interdisciplinary geoscientific and engineering research project. The project is designed to characterize and model reservoir architecture, pore systems and rock-fluid interactions at the pore to field scale in Upper Jurassic Smackover reef and carbonate shoal reservoirs associated with varying degrees of relief on pre-Mesozoic basement paleohighs in the northeastern Gulf of Mexico. The project effort includes the prediction of fluid flow in carbonate reservoirs through reservoir simulation modeling that utilizes geologic reservoir characterization and modeling and the prediction of carbonate reservoir architecture, heterogeneity and quality through seismic imaging. The primary objective of the project is to increase the profitability, producibility and efficiency of recovery of oil from existing and undiscovered Upper Jurassic fields characterized by reef and carbonate shoals associated with pre-Mesozoic basement paleohighs. The principal research effort for Year 3 of the project has been reservoir characterization, 3-D modeling, testing of the geologic-engineering model, and technology transfer. This effort has included six tasks: (1) the study of seismic attributes, (2) petrophysical characterization, (3) data integration, (4) the building of the geologic-engineering model, (5) the testing of the geologic-engineering model and (6) technology transfer. This work was scheduled for completion in Year 3. Progress on the project is as follows: geoscientific reservoir characterization is completed. The architecture, porosity types and heterogeneity of the reef and shoal reservoirs at Appleton and Vocation Fields have been characterized using geological and geophysical data. The study of rock-fluid interactions has been completed. Observations regarding the diagenetic processes influencing pore system development and heterogeneity in these reef and shoal reservoirs have been made. Petrophysical and engineering property characterization has been completed. Porosity and permeability data at Appleton and Vocation Fields have been analyzed, and well performance analysis has been conducted. Data integration is up to date, in that, the geological, geophysical, petrophysical and engineering data collected to date for Appleton and Vocation Fields have been compiled into a fieldwide digital database. 3-D geologic modeling of the structures and reservoirs at Appleton and Vocation Fields has been completed. The models represent an integration of geological, petrophysical and seismic data. 3-D reservoir simulation of the reservoirs at Appleton and Vocation Fields has been completed. The 3-D geologic models served as the framework for the simulations. The geologic-engineering models of the Appleton and Vocation Field reservoirs have been developed. These models are being tested. The geophysical interpretation for the paleotopographic feature being tested has been made, and the study of the data resulting from drilling of a well on this paleohigh is in progress. Numerous presentations on reservoir characterization and modeling at Appleton and Vocation Fields have been made at professional meetings and conferences and a short course on microbial reservoir characterization and modeling based on these fields has been prepared.

  2. Comparison of the PHISICS/RELAP5-3D Ring and Block Model Results for Phase I of the OECD MHTGR-350 Benchmark

    SciTech Connect (OSTI)

    Gerhard Strydom

    2014-04-01

    The INL PHISICS code system consists of three modules providing improved core simulation capability: INSTANT (performing 3D nodal transport core calculations), MRTAU (depletion and decay heat generation) and a perturbation/mixer module. Coupling of the PHISICS code suite to the thermal hydraulics system code RELAP5-3D has recently been finalized, and as part of the code verification and validation program the exercises defined for Phase I of the OECD/NEA MHTGR 350 MW Benchmark were completed. This paper provides an overview of the MHTGR Benchmark, and presents selected results of the three steady state exercises 1-3 defined for Phase I. For Exercise 1, a stand-alone steady-state neutronics solution for an End of Equilibrium Cycle Modular High Temperature Reactor (MHTGR) was calculated with INSTANT, using the provided geometry, material descriptions, and detailed cross-section libraries. Exercise 2 required the modeling of a stand-alone thermal fluids solution. The RELAP5-3D results of four sub-cases are discussed, consisting of various combinations of coolant bypass flows and material thermophysical properties. Exercise 3 combined the first two exercises in a coupled neutronics and thermal fluids solution, and the coupled code suite PHISICS/RELAP5-3D was used to calculate the results of two sub-cases. The main focus of the paper is a comparison of the traditional RELAP5-3D “ring” model approach vs. a much more detailed model that include kinetics feedback on individual block level and thermal feedbacks on a triangular sub-mesh. The higher fidelity of the block model is illustrated with comparison results on the temperature, power density and flux distributions, and the typical under-predictions produced by the ring model approach are highlighted.

  3. Combined results of searches for the standard model Higgs boson in pp collisions at sqrt(s) = 7 TeV

    E-Print Network [OSTI]

    CMS Collaboration

    2012-02-07

    Combined results are reported from searches for the standard model Higgs boson in proton-proton collisions at sqrt(s)=7 TeV in five Higgs boson decay modes: gamma pair, b-quark pair, tau lepton pair, W pair, and Z pair. The explored Higgs boson mass range is 110-600 GeV. The analysed data correspond to an integrated luminosity of 4.6-4.8 inverse femtobarns. The expected excluded mass range in the absence of the standard model Higgs boson is 118-543 GeV at 95% CL. The observed results exclude the standard model Higgs boson in the mass range 127-600 GeV at 95% CL, and in the mass range 129-525 GeV at 99% CL. An excess of events above the expected standard model background is observed at the low end of the explored mass range making the observed limits weaker than expected in the absence of a signal. The largest excess, with a local significance of 3.1 sigma, is observed for a Higgs boson mass hypothesis of 124 GeV. The global significance of observing an excess with a local significance greater than 3.1 sigma anywhere in the search range 110-600 (110-145) GeV is estimated to be 1.5 sigma (2.1 sigma). More data are required to ascertain the origin of this excess.

  4. Combined results of searches for the standard model Higgs boson in pp collisions at sqrt(s) = 7 TeV

    SciTech Connect (OSTI)

    Chatrchyan, Serguei; et al.

    2012-03-01

    Combined results are reported from searches for the standard model Higgs boson in proton-proton collisions at sqrt(s)=7 TeV in five Higgs boson decay modes: gamma pair, b-quark pair, tau lepton pair, W pair, and Z pair. The explored Higgs boson mass range is 110-600 GeV. The analysed data correspond to an integrated luminosity of 4.6-4.8 inverse femtobarns. The expected excluded mass range in the absence of the standard model Higgs boson is 118-543 GeV at 95% CL. The observed results exclude the standard model Higgs boson in the mass range 127-600 GeV at 95% CL, and in the mass range 129-525 GeV at 99% CL. An excess of events above the expected standard model background is observed at the low end of the explored mass range making the observed limits weaker than expected in the absence of a signal. The largest excess, with a local significance of 3.1 sigma, is observed for a Higgs boson mass hypothesis of 124 GeV. The global significance of observing an excess with a local significance greater than 3.1 sigma anywhere in the search range 110-600 (110-145) GeV is estimated to be 1.5 sigma (2.1 sigma). More data are required to ascertain the origin of this excess.

  5. Tracing the Mass during Low-Mass Star Formation, IV: Observations and Modeling of the Submillimeter Continuum Emission from Class I Protostars

    E-Print Network [OSTI]

    C. H. Young; Y. L. Shirley; N. J. Evans II; J. M. C. Rawlings

    2002-10-08

    We present results from the observations and modeling of seventeen Class I cores with the Submillimetre Common Users Bolometer Array (SCUBA) on the James Clerk Maxwell Telescope (JCMT). By modeling the transfer of radiation through the envelope for nine cores, we find, for a power law distribution n(r)=n_f(r/r_f)^-p, the average and standard deviation p=1.6 +/- 0.4 and a median of p=1.8. However, the inclusion of a disk or other point-like component can cause the derived p to be shallower by as much as 0.5. In addition, we test the Shu collapse model for our sources and discuss the application of simpler analyses that derive a density power law distribution directly from the slope of the intensity radial profile. The total mass of the envelope in our sample has a range from 0.04 to 5.0 M_sun, but these masses disagree with the virial masses derived from molecular line observations. Finally, we discuss the nature of these sources in light of various evolutionary indicators and find that T_bol and L_obs/L_smm are often inconsistent in distinguishing Class 0 from Class I cores.

  6. DUST FORMATION IN MACRONOVAE

    SciTech Connect (OSTI)

    Takami, Hajime; Ioka, Kunihito [Institute of Particle and Nuclear Studies, KEK, 1-1, Oho, Tsukuba 305-0801 (Japan); Nozawa, Takaya, E-mail: takami@post.kek.jp, E-mail: kunihito.ioka@kek.jp, E-mail: takaya.nozawa@nao.ac.jp [National Astronomical Observatory of Japan, 2-21-1, Osawa, Mitaka, Tokyo 181-8588 (Japan)

    2014-07-01

    We examine dust formation in macronovae (as known as kilonovae), which are the bright ejecta of neutron star binary mergers and one of the leading sites of r-process nucleosynthesis. In light of information about the first macronova candidate associated with GRB 130603B, we find that dust grains of r-process elements have difficulty forming because of the low number density of the r-process atoms, while carbon or elements lighter than iron can condense into dust if they are abundant. Dust grains absorb emission from ejecta with an opacity even greater than that of the r-process elements, and re-emit photons at infrared wavelengths. Such dust emission can potentially account for macronovae without r-process nucleosynthesis as an alternative model. This dust scenario predicts a spectrum with fewer features than the r-process model and day-scale optical-to-ultraviolet emission.

  7. The Epoch of Galaxy Formation

    E-Print Network [OSTI]

    Raul Jimenez

    2001-10-09

    I present a biased review of when the epoch of formation of galaxies (both disks and ellipticals) maybe took place. I base my arguments in simple (mostly) analytic models that have been recently developed to reproduce most of the observed photometric, chemical and dynamical properties of galaxies both at low and high redshift.

  8. Earth and Terrestrial Planet Formation

    E-Print Network [OSTI]

    Jacobson, Seth A

    2015-01-01

    The growth and composition of Earth is a direct consequence of planet formation throughout the Solar System. We discuss the known history of the Solar System, the proposed stages of growth and how the early stages of planet formation may be dominated by pebble growth processes. Pebbles are small bodies whose strong interactions with the nebula gas lead to remarkable new accretion mechanisms for the formation of planetesimals and the growth of planetary embryos. Many of the popular models for the later stages of planet formation are presented. The classical models with the giant planets on fixed orbits are not consistent with the known history of the Solar System, fail to create a high Earth/Mars mass ratio, and, in many cases, are also internally inconsistent. The successful Grand Tack model creates a small Mars, a wet Earth, a realistic asteroid belt and the mass-orbit structure of the terrestrial planets. In the Grand Tack scenario, growth curves for Earth most closely match a Weibull model. The feeding zon...

  9. Diffusive dynamics of contact formation in disordered polypeptides

    E-Print Network [OSTI]

    Gul Zerze; Jeetain Mittal; Robert B. Best

    2015-07-09

    Experiments measuring contact formation between a probe and quencher in disordered chains provide information on the fundamental dynamical timescales relevant to protein folding, but their interpretation usually relies on simplified one-dimensional (1D) diffusion models. Here, we use all-atom molecular simulations to capture both the time-scales of contact formation, as well as the scaling with the length of the peptide for tryptophan triplet quenching experiments. Capturing the experimental quenching times depends on the water viscosity, but more importantly on the configurational space explored by the chain. We also show that very similar results are obtained from Szabo-Schulten-Schulten theory applied to a 1D diffusion model derived from the simulations, supporting the validity of such models. However, we also find a significant reduction in diffusivity at small separations, those which are most important in determining the quenching rate.

  10. Diffusive dynamics of contact formation in disordered polypeptides

    E-Print Network [OSTI]

    Zerze, Gul; Best, Robert B

    2015-01-01

    Experiments measuring contact formation between a probe and quencher in disordered chains provide information on the fundamental dynamical timescales relevant to protein folding, but their interpretation usually relies on simplified one-dimensional (1D) diffusion models. Here, we use all-atom molecular simulations to capture both the time-scales of contact formation, as well as the scaling with the length of the peptide for tryptophan triplet quenching experiments. Capturing the experimental quenching times depends on the water viscosity, but more importantly on the configurational space explored by the chain. We also show that very similar results are obtained from Szabo-Schulten-Schulten theory applied to a 1D diffusion model derived from the simulations, supporting the validity of such models. However, we also find a significant reduction in diffusivity at small separations, those which are most important in determining the quenching rate.

  11. Kinetics of bond formation in crosslinked gelatin gels

    E-Print Network [OSTI]

    T. Abete; E. Del Gado; D. Hellio Serughetti; L. de Arcangelis; M. Djabourov; A. Coniglio

    2006-11-07

    In chemical crosslinking of gelatin solutions, two different time scales affect the kinetics of the gel formation in the experiments. We complement the experimental study with Monte Carlo numerical simulations of a lattice model. This approach shows that the two characteristic time scales are related to the formation of single bonds crosslinker-chain and of bridges between chains. In particular their ratio turns out to control the kinetics of the gel formation. We discuss the effect of the concentration of chains. Finally our results suggest that, by varying the probability of forming bridges as an independent parameter, one can finely tune the kinetics of the gelation via the ratio of the two characteristic times.

  12. Results from the Carbon-Land Model Intercomparison Project (C-LAMP) and availability of the data on the Earth System Grid (ESG)

    E-Print Network [OSTI]

    2007-01-01

    and Extensible Earth System Model for Climate Change Scienceincluded in the new Earth System Models (ESMs) participating

  13. Galaxy formation & evolution: the far-ir/sub-mm view

    E-Print Network [OSTI]

    M. Cirasuolo; J. S. Dunlop

    2008-10-07

    We review our current knowledge of the population of high-redshift sub-mm/mm galaxies, with particular emphasis on recent results from the SCUBA HAlf Degree Extragalactic Survey (SHADES). All available evidence indicates that these objects form the high-redshift, high-luminosity, high-mass tail of the dusty starforming galaxy population revealed at lower redshifts and luminosities by Spitzer. Current theoretical models of galaxy formation struggle to reproduce these extreme objects in the numbers indicated by current surveys.

  14. Comparison and validation of HEU and LEU modeling results to HEU experimental benchmark data for the Massachusetts Institute of Technology MITR reactor.

    SciTech Connect (OSTI)

    Newton, T. H.; Wilson, E. H; Bergeron, A.; Horelik, N.; Stevens, J. (Nuclear Engineering Division); (MIT Nuclear Reactor Lab.)

    2011-03-02

    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. Towards this goal, comparisons of MCNP5 Monte Carlo neutronic modeling results for HEU and LEU cores have been performed. Validation of the model has been based upon comparison to HEU experimental benchmark data for the MITR-II. The objective of this work was to demonstrate a model which could represent the experimental HEU data, and therefore could provide a basis to demonstrate LEU core performance. This report presents an overview of MITR-II model geometry and material definitions which have been verified, and updated as required during the course of validation to represent the specifications of the MITR-II reactor. Results of calculations are presented for comparisons to historical HEU start-up data from 1975-1976, and to other experimental benchmark data available for the MITR-II Reactor through 2009. This report also presents results of steady state neutronic analysis of an all-fresh LEU fueled core. Where possible, HEU and LEU calculations were performed for conditions equivalent to HEU experiments, which serves as a starting point for safety analyses for conversion of MITR-II from the use of HEU fuel to the use of UMo LEU fuel.

  15. On flame kernel formation and propagation in premixed gases

    SciTech Connect (OSTI)

    Eisazadeh-Far, Kian; Metghalchi, Hameed [Northeastern University, Mechanical and Industrial Engineering Department, Boston, MA 02115 (United States); Parsinejad, Farzan [Chevron Oronite Company LLC, Richmond, CA 94801 (United States); Keck, James C. [Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

    2010-12-15

    Flame kernel formation and propagation in premixed gases have been studied experimentally and theoretically. The experiments have been carried out at constant pressure and temperature in a constant volume vessel located in a high speed shadowgraph system. The formation and propagation of the hot plasma kernel has been simulated for inert gas mixtures using a thermodynamic model. The effects of various parameters including the discharge energy, radiation losses, initial temperature and initial volume of the plasma have been studied in detail. The experiments have been extended to flame kernel formation and propagation of methane/air mixtures. The effect of energy terms including spark energy, chemical energy and energy losses on flame kernel formation and propagation have been investigated. The inputs for this model are the initial conditions of the mixture and experimental data for flame radii. It is concluded that these are the most important parameters effecting plasma kernel growth. The results of laminar burning speeds have been compared with previously published results and are in good agreement. (author)

  16. Analysis of Star Formation in Galaxy-like Objects

    E-Print Network [OSTI]

    Patricia B. Tissera

    1999-12-20

    Using cosmological hydrodynamical simulations, we investigate the effects of hierarchical aggregation on the triggering of star formation in galactic-like objects. We include a simple star formation model to transform the cold gas in dense regions into stars. Simulations with different parameters have been performed in order to quantify the dependence of the results on the parameters. We then resort to stellar population synthesis models to trace the color evolution of each object with red-shift and in relation to their merger histories. We find that, in a hierarchical clustering scenario, the process of assembling of the structure is one natural mechanism that may trigger star formation. The resulting star formation rate history for each individual galactic object is composed of a continuous one ($\\leq 3 \\rm{M_{\\odot}/yr}$) and a series of star bursts. We find that even the accretion of a small satellite can be correlated with a stellar burst. Massive mergers are found to be more efficient at transforming gas into stars

  17. Basin Analysis of the Mississippi Interior Salt Basin and Petroleum System Modeling of the Jurassic Smackover Formation, Eastern Gulf Coastal Plain

    SciTech Connect (OSTI)

    Mancini, Ernest A.

    2003-02-06

    The project objectives are improving access to information for the Mississippi Interior Salt Basin by inventorying data files and records of the major information repositories in the region, making these inventories easily accessible in electronic format, increasing the amount of information available on domestic sedimentary basins through a comprehensive analysis of the Mississippi Interior Salt Basin, and enhancing the understanding of the petroleum systems operating in the Mississippi Interior Salt Basin.

  18. FY 2010 Fourth Quarter Report: Evaluation of the Dependency of Drizzle Formation on Aerosol Properties

    SciTech Connect (OSTI)

    Lin, W; McGraw, R; Liu, Y; Wang, J; Vogelmann, A; Daum, PH

    2010-10-01

    Metric for Quarter 4: Report results of implementation of composite parameterization in single-column model (SCM) to explore the dependency of drizzle formation on aerosol properties. To better represent VOCALS conditions during a test flight, the Liu-Duam-McGraw (LDM) drizzle parameterization is implemented in the high-resolution Weather Research and Forecasting (WRF) model, as well as in the single-column Community Atmosphere Model (CAM), to explore this dependency.

  19. Formation of porous gas hydrates

    E-Print Network [OSTI]

    Salamatin, Andrey N

    2015-01-01

    Gas hydrates grown at gas-ice interfaces are examined by electron microscopy and found to have a submicron porous texture. Permeability of the intervening hydrate layers provides the connection between the two counterparts (gas and water molecules) of the clathration reaction and makes further hydrate formation possible. The study is focused on phenomenological description of principal stages and rate-limiting processes that control the kinetics of the porous gas hydrate crystal growth from ice powders. Although the detailed physical mechanisms involved in the porous hydrate formation still are not fully understood, the initial stage of hydrate film spreading over the ice surface should be distinguished from the subsequent stage which is presumably limited by the clathration reaction at the ice-hydrate interface and develops after the ice grain coating is finished. The model reveals a time dependence of the reaction degree essentially different from that when the rate-limiting step of the hydrate formation at...

  20. A Comparison of Independent Star Formation Diagnostics for a UV-Selected Sample of Nearby Galaxies

    E-Print Network [OSTI]

    Sullivan, M; Chan, B; Cram, L; Ellis, R; Treyer, M A; Hopkins, A; Sullivan, Mark; Mobasher, Bahram; Chan, Ben; Cram, Lawrence; Ellis, Richard; Treyer, Marie; Hopkins, Andrew

    2001-01-01

    We present results from a decimetric radio survey undertaken with the Very Large Array as part of a longer term goal to inter-compare star formation and dust extinction diagnostics, on a galaxy by galaxy basis, for a representative sample of nearby galaxies. For our survey field, Selected Area 57, star formation rates derived from 1.4GHz luminosities are compared with earlier nebular emission line and ultraviolet (UV) continuum diagnostics. We find broad correlations, over several decades in luminosity, between H-alpha, the UV continuum and 1.4GHz diagnostics. However, the scatter in these relations is found to be larger than observational errors, with offsets between the observed relations and those expected assuming constant star-formation histories and luminosity-independent extinction models. We investigate the physical origin of the observed relations, and conclude the discrepancies between different star-formation diagnostics can only be partly explained by simple models of dust extinction in galaxies. ...

  1. Constraining dark matter halo profiles and galaxy formation models using spiral arm morphology. II. Dark and stellar mass concentrations for 13 nearby face-on galaxies

    SciTech Connect (OSTI)

    Seigar, Marc S. [Department of Physics, University of Minnesota Duluth, 1023 University Drive, MWAH 371, Duluth, MN 55812-3009 (United States); Davis, Benjamin L.; Berrier, Joel; Kennefick, Daniel [Arkansas Center for Space and Planetary Sciences, 202 Field House, University of Arkansas, Fayetteville, AR 72701 (United States)

    2014-11-01

    We investigate the use of spiral arm pitch angles as a probe of disk galaxy mass profiles. We confirm our previous result that spiral arm pitch angles (P) are well correlated with the rate of shear (S) in disk galaxy rotation curves. We use this correlation to argue that imaging data alone can provide a powerful probe of galactic mass distributions out to large look-back times. We then use a sample of 13 galaxies, with Spitzer 3.6 ?m imaging data and observed H? rotation curves, to demonstrate how an inferred shear rate coupled with a bulge-disk decomposition model and a Tully-Fisher-derived velocity normalization can be used to place constraints on a galaxy's baryon fraction and dark matter halo profile. Finally, we show that there appears to be a trend (albeit a weak correlation) between spiral arm pitch angle and halo concentration. We discuss implications for the suggested link between supermassive black hole (SMBH) mass and dark halo concentration, using pitch angle as a proxy for SMBH mass.

  2. New Particle Formation Study Final Campaign Report

    SciTech Connect (OSTI)

    Smith, JN; McMurry, PH

    2015-01-01

    The scientific foci of the New Particle Formation Study were the formation and evolution of atmospheric aerosols and the impacts of newly formed particles on cloud processes. Specifically, we planned to: (1) to identify the species and mechanisms responsible for the initial steps of new particle formation, i.e., the formation of thermodynamically stable clusters; (2) investigate the role of acid-base chemistry in new particle growth through measurements of ammonia and amines as well as organic and inorganic acids in both atmospheric nanoparticles and the gas phase; (3) investigate the contribution of other surface area or volume-controlled processes to nanoparticle formation and growth; (4) create a comprehensive dataset related to new particle formation and growth that can be used as input for our own thermodynamic models as well as the modeling efforts by our Department of Energy (DOE) Aerosol Life Cycle working group collaborators; (5) characterize the increase of the number and activity of cloud condensation nuclei (CCN) due to particle formation and growth; (6) determine the regional extent of new particle formation to address the role that atmospheric transport plays in determining the impacts, if any, of new particle formation on cloud number and properties.

  3. Results from the Carbon-Land Model Intercomparison Project (C-LAMP) and availability of the data on the Earth System Grid (ESG)

    E-Print Network [OSTI]

    2007-01-01

    and Extensible Earth System Model for Climate Change Scienceincluded in the new Earth System Models (ESMs) participatingof the C-LAMP model output via the Earth System Grid (ESG).

  4. Sensitivity and Scenario Results

    E-Print Network [OSTI]

    Yu, Winston

    Presents the results of various scenarios using models used to study water, climate, agriculture and the economy in Pakistan's Indus Basin, and discusses the policy and investment implications. The water allocations per ...

  5. On The History and Future of Cosmic Planet Formation

    E-Print Network [OSTI]

    Behroozi, Peter

    2015-01-01

    We combine constraints on galaxy formation histories with planet formation models, yielding the Earth-like and giant planet formation histories of the Milky Way and the Universe as a whole. In the Hubble Volume (10^13 Mpc^3), we expect there to be ~10^20 Earth-like and ~10^20 giant planets; our own galaxy is expected to host ~10^9 and ~10^10 Earth-like and giant planets, respectively. Proposed metallicity thresholds for planet formation do not significantly affect these numbers. However, the metallicity dependence for giant planets results in later typical formation times and larger host galaxies than for Earth-like planets. The Solar System formed at the median age for existing giant planets in the Milky Way, and consistent with past estimates, formed after 80% of Earth-like planets. However, if existing gas within virialised dark matter haloes continues to collapse and form stars and planets, the Universe will form over 10 times more planets than currently exist. We show that this would imply at least a 92%...

  6. NO[sub x] formation in unsteady combustion

    SciTech Connect (OSTI)

    Norton, T.S.; Richards, G.A. (USDOE Morgantown Energy Technology Center, WV (United States)); Narayanaswami, L.L. (Embry-Riddle Aeronautical Univ., Daytona Beach, FL (United States))

    1992-01-01

    It has been found that fuel-lean operating conditions produce the best results for the current aerovalve pulse combustor. Under these conditions, the levels of unburned hydrocarbon pollutants in the exhaust stream are negligibly low. Initial results on CO indicate that the gas chromatograph method (thermal conductivity detector) is not sensitive enough to measure concentrations below 500 ppM. The modeling work involves the modification of an existing Thermal Pulse Combustor code to include some detailed chemistry. Two methods are used. In the first method, a kinetic mechanism for the formation of thermal NO is superimposed onto the oscillating field of temperature and pressure predicted by the existing pulse combustor model. The concentrations of oxygen atoms and N[sub 2], which control the NO formation step, are estimated from an equilibrium calculation at each temperature and pressure condition. Then the NO formation rate is determined from the rate of the reaction N[sub 2] + 0 --> NO + N. In the second method, more detailed chemistry is incorporated into the base model and the chemical heat release equations are used to drive the pulsations instead of vice versa. The 0-atom concentration is determined from a complex series of chain reactions, rather than by equilibrium.

  7. NO{sub x} formation in unsteady combustion

    SciTech Connect (OSTI)

    Norton, T.S.; Richards, G.A. [USDOE Morgantown Energy Technology Center, WV (United States); Narayanaswami, L.L. [Embry-Riddle Aeronautical Univ., Daytona Beach, FL (United States)

    1992-12-01

    It has been found that fuel-lean operating conditions produce the best results for the current aerovalve pulse combustor. Under these conditions, the levels of unburned hydrocarbon pollutants in the exhaust stream are negligibly low. Initial results on CO indicate that the gas chromatograph method (thermal conductivity detector) is not sensitive enough to measure concentrations below 500 ppM. The modeling work involves the modification of an existing Thermal Pulse Combustor code to include some detailed chemistry. Two methods are used. In the first method, a kinetic mechanism for the formation of thermal NO is superimposed onto the oscillating field of temperature and pressure predicted by the existing pulse combustor model. The concentrations of oxygen atoms and N{sub 2}, which control the NO formation step, are estimated from an equilibrium calculation at each temperature and pressure condition. Then the NO formation rate is determined from the rate of the reaction N{sub 2} + 0 --> NO + N. In the second method, more detailed chemistry is incorporated into the base model and the chemical heat release equations are used to drive the pulsations instead of vice versa. The 0-atom concentration is determined from a complex series of chain reactions, rather than by equilibrium.

  8. The star formation main sequence and stellar mass assembly of galaxies in the Illustris simulation

    E-Print Network [OSTI]

    Sparre, Martin

    Understanding the physical processes that drive star formation is a key challenge for galaxy formation models. In this paper, we study the tight correlation between the star formation rate (SFR) and stellar mass of galaxies ...

  9. Structure formation in the presence of dark energy perturbations

    E-Print Network [OSTI]

    L. R. Abramo; R. C. Batista; L. Liberato; R. Rosenfeld

    2007-11-28

    We study non-linear structure formation in the presence of dark energy. The influence of dark energy on the growth of large-scale cosmological structures is exerted both through its background effect on the expansion rate, and through its perturbations as well. In order to compute the rate of formation of massive objects we employ the Spherical Collapse formalism, which we generalize to include fluids with pressure. We show that the resulting non-linear evolution equations are identical to the ones obtained in the Pseudo-Newtonian approach to cosmological perturbations, in the regime where an equation of state serves to describe both the background pressure relative to density, and the pressure perturbations relative to the density perturbations as well. We then consider a wide range of constant and time-dependent equations of state (including phantom models) parametrized in a standard way, and study their impact on the non-linear growth of structure. The main effect is the formation of dark energy structure associated with the dark matter halo: non-phantom equations of state induce the formation of a dark energy halo, damping the growth of structures; phantom models, on the other hand, generate dark energy voids, enhancing structure growth. Finally, we employ the Press-Schechter formalism to compute how dark energy affects the number of massive objects as a function of redshift.

  10. SIMULATION OF THE FORMATION OF A SOLAR ACTIVE REGION

    SciTech Connect (OSTI)

    Cheung, M. C. M.; Title, A. M. [Lockheed Martin Solar and Astrophysics Laboratory, Palo Alto, CA 94304 (United States); Rempel, M. [High Altitude Observatory, NCAR, P.O. Box 3000, Boulder, CO 80307 (United States); Schuessler, M. [Max Planck Institute for Solar System Research, Katlenburg-Lindau, 37191 (Germany)

    2010-09-01

    We present a radiative magnetohydrodynamics simulation of the formation of an active region (AR) on the solar surface. The simulation models the rise of a buoyant magnetic flux bundle from a depth of 7.5 Mm in the convection zone up into the solar photosphere. The rise of the magnetic plasma in the convection zone is accompanied by predominantly horizontal expansion. Such an expansion leads to a scaling relation between the plasma density and the magnetic field strength such that B {proportional_to} rhov{sup 1/2}. The emergence of magnetic flux into the photosphere appears as a complex magnetic pattern, which results from the interaction of the rising magnetic field with the turbulent convective flows. Small-scale magnetic elements at the surface first appear, followed by their gradual coalescence into larger magnetic concentrations, which eventually results in the formation of a pair of opposite polarity spots. Although the mean flow pattern in the vicinity of the developing spots is directed radially outward, correlations between the magnetic field and velocity field fluctuations allow the spots to accumulate flux. Such correlations result from the Lorentz-force-driven, counterstreaming motion of opposite polarity fragments. The formation of the simulated AR is accompanied by transient light bridges between umbrae and umbral dots. Together with recent sunspot modeling, this work highlights the common magnetoconvective origin of umbral dots, light bridges, and penumbral filaments.

  11. First Structure Formation and the First Stars

    E-Print Network [OSTI]

    Michael L. Norman; Tom Abel; Greg Bryan

    2000-05-11

    We discuss the results of recent 3D simulations of first structure formation in relationship to the formation of the first stars. On the basis of a new, high-resolution AMR simulation (spatial dynamic range = 30,000,000), we conclude that the first stars are likely to be massive.

  12. Heating tar sands formations to visbreaking temperatures

    DOE Patents [OSTI]

    Karanikas, John Michael (Houston, TX); Colmenares, Tulio Rafael (Houston, TX); Zhang, Etuan (Houston, TX); Marino, Marian (Houston, TX); Roes, Augustinus Wilhelmus Maria (Houston, TX); Ryan, Robert Charles (Houston, TX); Beer, Gary Lee (Houston, TX); Dombrowski, Robert James (Houston, TX); Jaiswal, Namit (Houston, TX)

    2009-12-22

    Methods for treating a tar sands formation are described herein. Methods may include heating at least a section of a hydrocarbon layer in the formation from a plurality of heaters located in the formation. The heat may be controlled so that at least a majority of the section reaches an average temperature of between 200.degree. C. and 240.degree. C., which results in visbreaking of at least some hydrocarbons in the section. At least some visbroken hydrocarbon fluids may be produced from the formation.

  13. American Institute of Aeronautics and Astronautics Compact Toroid Formation using an Annular Helicon

    E-Print Network [OSTI]

    Walker, Mitchell

    Institute of Technology, Atlanta, GA. 30332 Formation and ejection of compact plasma toroids for high development. In particular, use of field-reversed configuration plasma with an annular helicon pre or grids that limit lifetime and reliability. Results from modeling the pulsed power system, the FRC

  14. Glass foams: formation, transport properties, and heat, mass, and radiation transfer

    E-Print Network [OSTI]

    Pilon, Laurent

    Glass foams: formation, transport properties, and heat, mass, and radiation transfer Andrei G models for thermophysical and transport properties and heat, mass, and radiation transfer in glass foams. In addition, the new results on simulation of combined conduction and radiation heat transfer in glass foams

  15. Vehicle Technologies Office Merit Review 2015: First Principles Modeling of SEI Formation on Bare and Surface/Additive Modified Silicon Anodes

    Broader source: Energy.gov [DOE]

    Presentation given by Texas A&M at 2015 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about first principles modeling of...

  16. Petrophysical evaluation of subterranean formations

    DOE Patents [OSTI]

    Klein, James D; Schoderbek, David A; Mailloux, Jason M

    2013-05-28

    Methods and systems are provided for evaluating petrophysical properties of subterranean formations and comprehensively evaluating hydrate presence through a combination of computer-implemented log modeling and analysis. Certain embodiments include the steps of running a number of logging tools in a wellbore to obtain a variety of wellbore data and logs, and evaluating and modeling the log data to ascertain various petrophysical properties. Examples of suitable logging techniques that may be used in combination with the present invention include, but are not limited to, sonic logs, electrical resistivity logs, gamma ray logs, neutron porosity logs, density logs, NRM logs, or any combination or subset thereof.

  17. Implementing Feedback in Simulations of Galaxy Formation: A Survey of Methods

    E-Print Network [OSTI]

    R. J. Thacker; H. M. P. Couchman

    2000-01-15

    We present a detailed investigation of different approaches to modeling feedback in simulations of galaxy formation. Gas-dynamic forces are evaluated using Smoothed Particle Hydrodynamics (SPH) while star formation and supernova feedback are included using a three parameter model which determines the star formation rate normalization, feedback energy and lifetime of feedback regions. The star formation rate is calculated using a Lagrangian Schmidt Law for all gas particles which satisfy temperature, density and convergent flow criteria. Feedback is incorporated as thermal heating of the ISM. We compare the effects of distributing this energy over the smoothing scale or depositing it on a single particle. Radiative losses are prevented from heated particles by adjusting the density used in radiative cooling. We test the models on the formation of galaxies from cosmological initial conditions and also on isolated Milky Way and dwarf galaxies. Extremely violent feedback is necessary to produce a gas disk with angular momentum remotely close to that of observed disk galaxies. This is a result of the extreme central concentration of the dark halos in the sCDM model, and the pervasiveness of the core-halo angular momentum transport mechanism. We emphasize that the disks formed in hierarchical simulations are partially a numerical artifact produced by the minimum mass scale of the simulation acting as a highly efficient `support' mechanism. Disk formation is strongly affected by the treatment of dense regions in SPH, which along with the difficulty of representing the hierarchical formation process, means that realistic simulations of galaxy formation require far higher resolution than currently used.

  18. CGILS: Results from the First Phase of an International Project to Understand the Physical Mechanisms of Low Cloud Feedbacks in Single Column Models

    SciTech Connect (OSTI)

    Zhang, Minghua; Bretherton, Christopher S.; Blossey, Peter; Austin, Phillip A.; Bacmeister, J.; Bony, Sandrine; Brient, Florent; Cheedela, Suvarchal K.; Cheng, Anning; Del Genio, Anthony D.; De Roode, Stephan R.; Endo , Satoshi; Franklin, Charmaine N.; Golaz, Jean-Christophe; Hannay, Cecile; Heus, Thijs; Isotta, Francesco A.; Jean-Louis, Dufresne; Kang, In-Sik; Kawai, Hideaki; Koehler, M.; Larson, Vincent E.; Liu, Yangang; Lock, Adrian; Lohmann, U.; Khairoutdinov, Marat; Molod, Andrea M.; Neggers, Roel; Rasch, Philip J.; Sandu, Irina; Senkbeil, Ryan; Siebesma, A. P.; Siegenthaler-Le Drian, Colombe; Stevens, Bjorn; Suarez, Max; Xu, Kuan-Man; Von Salzen, Knut; Webb, Mark; Wolf, Audrey; Zhao, M.

    2013-12-26

    Large Eddy Models (LES) and Single Column Models (SCM) are used in a surrogate climate change 101 to investigate the physical mechanism of low cloud feedbacks in climate models. Enhanced surface-102 driven boundary layer turbulence and shallow convection in a warmer climate are found to be 103 dominant mechanisms in SCMs.

  19. Liquid drops on a surface: using density functional theory to calculate the binding potential and drop profiles and comparing with results from mesoscopic modelling

    E-Print Network [OSTI]

    Adam P. Hughes; Uwe Thiele; Andrew J. Archer

    2015-01-28

    The contribution to the free energy for a film of liquid of thickness $h$ on a solid surface, due to the interactions between the solid-liquid and liquid-gas interfaces is given by the binding potential, $g(h)$. The precise form of $g(h)$ determines whether or not the liquid wets the surface. Note that differentiating $g(h)$ gives the Derjaguin or disjoining pressure. We develop a microscopic density functional theory (DFT) based method for calculating $g(h)$, allowing us to relate the form of $g(h)$ to the nature of the molecular interactions in the system. We present results based on using a simple lattice gas model, to demonstrate the procedure. In order to describe the static and dynamic behaviour of non-uniform liquid films and drops on surfaces, a mesoscopic free energy based on $g(h)$ is often used. We calculate such equilibrium film height profiles and also directly calculate using DFT the corresponding density profiles for liquid drops on surfaces. Comparing quantities such as the contact angle and also the shape of the drops, we find good agreement between the two methods. We also study in detail the effect on $g(h)$ of truncating the range of the dispersion forces, both those between the fluid molecules and those between the fluid and wall. We find that truncating can have a significant effect on $g(h)$ and the associated wetting behaviour of the fluid.

  20. A model-data intercomparison of CO2 exchange across North America: Results from the North American Carbon Program Site Synthesis

    SciTech Connect (OSTI)

    Schwalm, C.R.; Williams, C.A.; Schaefer, K.; Anderson, R.; Arain, M.A.; Baker, I.; Black, T.A.; Chen, G.; Ciais, P.; Davis, K. J.; Desai, A. R.; Dietze, M.; Dragoni, D.; Fischer, M.L.; Flanagan, L.B.; Grant, R.F.; Gu, L.; Hollinger, D.; Izaurralde, R.C.; Kucharik, C.; Lafleur, P.M.; Law, B.E.; Li, L.; Li, Z.; Liu, S.; Lokupitiya, E.; Luo, Y.; Ma, S.; Margolis, H.; Matamala, R.; McCaughey, H.; Monson, R. K.; Oechel, W. C.; Peng, C.; Poulter, B.; Price, D.T.; Riciutto, D.M.; Riley, W.J.; Sahoo, A.K.; Sprintsin, M.; Sun, J.; Tian, H.; Tonitto, C.; Verbeeck, H.; Verma, S.B.

    2011-06-01

    Our current understanding of terrestrial carbon processes is represented in various models used to integrate and scale measurements of CO{sub 2} exchange from remote sensing and other spatiotemporal data. Yet assessments are rarely conducted to determine how well models simulate carbon processes across vegetation types and environmental conditions. Using standardized data from the North American Carbon Program we compare observed and simulated monthly CO{sub 2} exchange from 44 eddy covariance flux towers in North America and 22 terrestrial biosphere models. The analysis period spans {approx}220 site-years, 10 biomes, and includes two large-scale drought events, providing a natural experiment to evaluate model skill as a function of drought and seasonality. We evaluate models' ability to simulate the seasonal cycle of CO{sub 2} exchange using multiple model skill metrics and analyze links between model characteristics, site history, and model skill. Overall model performance was poor; the difference between observations and simulations was {approx}10 times observational uncertainty, with forested ecosystems better predicted than nonforested. Model-data agreement was highest in summer and in temperate evergreen forests. In contrast, model performance declined in spring and fall, especially in ecosystems with large deciduous components, and in dry periods during the growing season. Models used across multiple biomes and sites, the mean model ensemble, and a model using assimilated parameter values showed high consistency with observations. Models with the highest skill across all biomes all used prescribed canopy phenology, calculated NEE as the difference between GPP and ecosystem respiration, and did not use a daily time step.

  1. Formation of in-volume nanogratings with sub-100 nm periods in glass by femtosecond laser irradiation

    E-Print Network [OSTI]

    Liao, Yang; Cui, Yun; Qiao, Lingling; Bellouard, Yves; Sugioka, Koji; Cheng, Ya

    2015-01-01

    We present direct experimental observation of the morphological evolution during the formation of nanogratings with sub-100-nm periods with the increasing number of pulses. Theoretical simulation shows that the constructive interference of the scattering light from original nanoplanes will create an intensity maximum located between the two adjacent nanoplanes, resulting in shortening of the nanograting period by half. The proposed mechanism enables explaining the formation of nanogratings with periods beyond that predicted by the nanoplasmonic model.

  2. Planet formation and migration

    E-Print Network [OSTI]

    John C B Papaloizou; Caroline Terquem

    2005-11-28

    We review the observations of extrasolar planets, ongoing developments in theories of planet formation, orbital migration, and the evolution of multiplanet systems.

  3. The star formation histories of galaxies in the Sloan Digital Sky Survey

    E-Print Network [OSTI]

    Ben Panter; Raul Jimenez; Alan F. Heavens; Stephane Charlot

    2007-04-24

    We present the results of a MOPED analysis of ~3 x 10^5 galaxy spectra from the Sloan Digital Sky Survey Data Release Three (SDSS DR3), with a number of improvements in data, modelling and analysis compared with our previous analysis of DR1. The improvements include: modelling the galaxies with theoretical models at a higher spectral resolution of 3\\AA; better calibrated data; an extended list of excluded emission lines, and a wider range of dust models. We present new estimates of the cosmic star formation rate, the evolution of stellar mass density and the stellar mass function from the fossil record. In contrast to our earlier work the results show no conclusive peak in the star formation rate out to a redshift around 2 but continue to show conclusive evidence for `downsizing' in the SDSS fossil record. The star formation history is now in good agreement with more traditional instantaneous measures. The galaxy stellar mass function is determined over five decades of mass, and an updated estimate of the current stellar mass density is presented. We also investigate the systematic effects of changes in the stellar population modelling, the spectral resolution, dust modelling, sky lines, spectral resolution and the change of data set. We find that the main changes in the results are due to the improvements in the calibration of the SDSS data, changes in the initial mass function and the theoretical models used.

  4. System-level modeling for geological storage of CO2

    E-Print Network [OSTI]

    Zhang, Yingqi; Oldenburg, Curtis M.; Finsterle, Stefan; Bodvarsson, Gudmundur S.

    2006-01-01

    of Geologic Storage of CO2, in Carbon Dioxide Capture forFormations - Results from the CO2 Capture Project: GeologicBenson, Process Modeling of CO2 Injection into Natural Gas

  5. Recombination energy in double white dwarf formation

    E-Print Network [OSTI]

    Nandez, Jose L A; Lombardi, James C

    2015-01-01

    In this Letter we investigate the role of recombination energy during a common envelope event. We confirm that taking this energy into account helps to avoid the formation of the circumbinary envelope commonly found in previous studies. For the first time, we can model a complete common envelope event, with a clean compact double white dwarf binary system formed at the end. The resulting binary orbit is almost perfectly circular. In addition to considering recombination energy, we also show that between 1/4 and 1/2 of the released orbital energy is taken away by the ejected material. We apply this new method to the case of the double-white dwarf system WD 1101+364, and we find that the progenitor system at the start of the common envelope event consisted of a $\\sim1.5M_\\odot$ red giant star in a $\\sim 30$ day orbit with a white dwarf companion.

  6. Composition Mixing during Blue Straggler Formation and Evolution

    E-Print Network [OSTI]

    Eric L. Sandquist; Michael Bolte; Lars Hernquist

    1996-09-25

    We use smoothed-particle hydrodynamics to examine differences between direct collisions of single stars and binary star mergers in their roles as possible blue straggler star formation mechanisms. We find in all cases that core helium in the progenitor stars is largely retained in the core of the remnant, almost independent of the type of interaction or the central concentration of the progenitor stars. We have also modelled the subsequent evolution of the hydrostatic remnants, including mass loss and energy input from the hydrodynamical interaction. The combination of the hydrodynamical and hydrostatic models enables us to predict that little mixing will occur during the merger of two globular cluster stars of equal mass. In contrast to the results of Proctor Sills, Bailyn, & Demarque (1995), we find that neither completely mixed nor unmixed models can match the absolute colors of observed blue stragglers in NGC 6397 at all luminosity levels. We also find that the color distribution is probably the crucial test for explanations of BSS formation - if stellar collisions or mergers are the correct mechanisms, a large fraction of the lifetime of the straggler must be spent away from the main sequence. This constraint appears to rule out the possibility of completely mixed models. For NGC 6397, unmixed models predict blue straggler lifetimes ranging from about 0.1 to 4 Gyr, while completely mixed models predict a range from about 0.6 to 4 Gyr.

  7. Basin Analysis of the Mississippi Interior Salt Basin and Petroleum System Modeling of the Jurassic Smackover Formation, Eastern Gulf Coastal Plain, Final Report and Topical Reports 5-8 on Smackover Petroleum system and Underdevelopment Reservoirs

    SciTech Connect (OSTI)

    Mancini, Ernest A.; Puckett, T. Markham; Parcell, William C.; Llinas, Juan Carlos; Kopaska-Merkel, David C.; Townsend, Roger N.

    2002-03-05

    The Smackover Formation, a major hydrocarbon-producing horizon in the Mississippi Interior Salt Basin (MISB), conformably overlies the Norphlet Formation and is conformably overlain by the Buckner Anhydrite Member of the Haynesville Formation. The Norphlet-Smackover contact can be either gradational or abrupt. The thickness and lithofacies distribution of the Smackover Formation were controlled by the configuration of incipient paleotopography. The Smackover Formation has been subdivided into three informal members, referred to as the lower, middle and upper members.

  8. Interfacial reactions in epitaxial Al/TiN(111) model diffusion barriers: Formation of an impervious self-limited wurtzite-structure AIN(0001) blocking layer

    SciTech Connect (OSTI)

    Chun, J.-S.; Desjardins, P.; Lavoie, C.; Shin, C.-S.; Cabral, C.; Petrov, I.; Greene, J. E.

    2001-06-15

    Single-crystal TiN(111) layers, 45 nm thick, were grown on MgO(111) by ultrahigh vacuum reactive magnetron sputter deposition in pure N{sub 2} discharges at T{sub s}=700{degree}C. Epitaxial Al(111) overlayers, 160 nm thick, were then deposited at T{sub s}=100{degree}C in Ar without breaking vacuum. Interfacial reactions and changes in bilayer microstructure due to annealing at 620 and 650{degree}C were investigated using x-ray diffraction and transmission electron microscopy (TEM). The interfacial regions of samples annealed at 620{degree}C consist of continuous {approx_equal}7-nm-thick epitaxial wurtzite-structure AlN(0001) layers containing a high density of stacking faults, with {approx_equal}22 nm thick tetragonal Al{sub 3}Ti(112) overlayers. Surprisingly, samples annealed at the higher temperature are more stable against Al{sub 3}Ti formation. TEM analyses of bilayers annealed at 650{degree}C (10{degree}C below the Al melting point!) reveal only the self-limited growth of an {approx_equal}3-nm-thick interfacial layer of perfect smooth epitaxial wurtzite-structure AlN(0001) which serves as an extremely effective deterrent for preventing further interlayer reactions. {copyright} 2001 American Institute of Physics.

  9. Application of MELCOR Code to a French PWR 900 MWe Severe Accident Sequence and Evaluation of Models Performance Focusing on In-Vessel Thermal Hydraulic Results

    SciTech Connect (OSTI)

    De Rosa, Felice [ENEA, Italian National Agency for New Technologies, Energy and the Environment (Italy)

    2006-07-01

    In the ambit of the Severe Accident Network of Excellence Project (SARNET), funded by the European Union, 6. FISA (Fission Safety) Programme, one of the main tasks is the development and validation of the European Accident Source Term Evaluation Code (ASTEC Code). One of the reference codes used to compare ASTEC results, coming from experimental and Reactor Plant applications, is MELCOR. ENEA is a SARNET member and also an ASTEC and MELCOR user. During the first 18 months of this project, we performed a series of MELCOR and ASTEC calculations referring to a French PWR 900 MWe and to the accident sequence of 'Loss of Steam Generator (SG) Feedwater' (known as H2 sequence in the French classification). H2 is an accident sequence substantially equivalent to a Station Blackout scenario, like a TMLB accident, with the only difference that in H2 sequence the scram is forced to occur with a delay of 28 seconds. The main events during the accident sequence are a loss of normal and auxiliary SG feedwater (0 s), followed by a scram when the water level in SG is equal or less than 0.7 m (after 28 seconds). There is also a main coolant pumps trip when {delta}Tsat < 10 deg. C, a total opening of the three relief valves when Tric (core maximal outlet temperature) is above 603 K (330 deg. C) and accumulators isolation when primary pressure goes below 1.5 MPa (15 bar). Among many other points, it is worth noting that this was the first time that a MELCOR 1.8.5 input deck was available for a French PWR 900. The main ENEA effort in this period was devoted to prepare the MELCOR input deck using the code version v.1.8.5 (build QZ Oct 2000 with the latest patch 185003 Oct 2001). The input deck, completely new, was prepared taking into account structure, data and same conditions as those found inside ASTEC input decks. The main goal of the work presented in this paper is to put in evidence where and when MELCOR provides good enough results and why, in some cases mainly referring to its specific models (candling, corium pool behaviour, etc.) they were less good. A future work will be the preparation of an input deck for the new MELCOR 1.8.6. and to perform a code-to-code comparison with ASTEC v1.2 rev. 1. (author)

  10. Search results | Department of Energy

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

    results Search results Enter terms Search Showing 41 - 50 of 42 results. Download Solar Cell Simulation Students model the flow of energy from the sun as it enters a...

  11. Search results | Department of Energy

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

    results Search results Enter terms Search Showing 51 - 60 of 59 results. Download Solar Cell Simulation Students model the flow of energy from the sun as it enters a...

  12. Search results | Department of Energy

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

    results Search results Enter terms Search Showing 11 - 20 of 12 results. Download Solar Cell Simulation Students model the flow of energy from the sun as it enters a...

  13. Search results | Department of Energy

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

    results Search results Enter terms Search Showing 51 - 60 of 53 results. Download Solar Cell Simulation Students model the flow of energy from the sun as it enters a...

  14. Search results | Department of Energy

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

    Search results Search results Enter terms Search Showing 41 - 50 of 42 results. Download Solar Cell Simulation Students model the flow of energy from the sun as it enters a...

  15. Search results | Department of Energy

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

    Search results Search results Enter terms Search Showing 11 - 20 of 12 results. Download Solar Cell Simulation Students model the flow of energy from the sun as it enters a...

  16. Search results | Department of Energy

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

    Search results Search results Enter terms Search Showing 51 - 60 of 53 results. Download Solar Cell Simulation Students model the flow of energy from the sun as it enters a...

  17. Thermal, chemical, and mass-transport processes induced in abyssal sediments by the emplacement of nuclear waste: experimental and modeling results

    SciTech Connect (OSTI)

    McVey, D.F.; Erickson, K.L.; Seyfried, W.

    1980-01-01

    This paper discusses heat and mass transport studies of marine red clay sediments being considered as a nuclear waste isolation medium. Numerical models indicate that for a maximum allowable sediment/canister interface temperature of 200 to 250/sup 0/C, the sediment can absorb about 1.5 kW initial power from waste in a 3 m long by 0.3 m dia canister buried 30 m in the sediment. Fluid displacement due to convection is found to be less than 1 m. Laboratory studies of the geochemical effects induced by heating sediment/seawater mixtures indicate that the canister and waste form must be designed to resist a hot, acid (pH 3 to 4) oxidizing environment. Since the thermally altered sediment volume of about 5.5 m/sup 3/ is small relative to the sediment volume overlying the canister, the acid and oxidizing conditions are not anticipated to effect the properties of the far field. Using sorption coefficient correlations, the migration of four nuclides /sup 239/Pu, /sup 137/Cs, /sup 129/I, and /sup 99/Tc were computer for a canister buried 30 m deep in a 60 m thick red clay sediment layer. It was found that the /sup 239/Pu and /sup 137/Cs are essentially completely contained in the sediments, while /sup 129/I and /sup 99/Tc broke through the 30 m of sediment in about 5000 years. The resultant peak injection rates of 4.6 x 10/sup -5/ ..mu..Ci/year-m/sup 2/ for /sup 129/I and 1.6 x 10/sup -2/ ..mu..Ci/year-m/sup 2/ for /sup 99/Tc were less than the natural radioactive flux of /sup 226/Ra (3.5 to 8.8 x 10/sup -4/ ..mu..Ci/year-m/sup 2/) and /sup 222/Rn (0.26 to 0.88 ..mu..Ci/year-m/sup 2/).

  18. Downscaling Global Land Cover Projections from an Integrated Assessment Model for Use in Regional Analyses: Results and Evaluation for the US from 2005 to 2095

    SciTech Connect (OSTI)

    West, Tristram O.; Le Page, Yannick LB; Huang, Maoyi; Wolf, Julie; Thomson, Allison M.

    2014-06-05

    Projections of land cover change generated from Integrated Assessment Models (IAM) and other economic-based models can be applied for analyses of environmental impacts at subregional and landscape scales. For those IAM and economic models that project land use at the sub-continental or regional scale, these projections must be downscaled and spatially distributed prior to use in climate or ecosystem models. Downscaling efforts to date have been conducted at the national extent with relatively high spatial resolution (30m) and at the global extent with relatively coarse spatial resolution (0.5 degree).

  19. Formation of the intermediate baryon systems in hadron-nuclear and nuclear-nuclear interactions

    E-Print Network [OSTI]

    M. K. Suleymanov; E. U. Khan; A Kravchakova; Mahnaz Q. Haseeb; S. M. Saleem; Y. H. Huseynaliyev; S Vokal; A. S. Vodopianov; O. B. Abdinov

    2007-12-17

    The centrality experiments indicate regime change and saturation in the behavior of some characteristics of the secondary particles emitted in hadron-nuclear and nuclear-nuclear interactions at high energies. The phenomenon has a critical character. The simple models do not explain the effect. We suppose that the responsible mechanism to explain the phenomenon could be the formation and decay of the intermediate baryon systems. Such systems could be formed as a result of nucleon percolation in compressed baryonic matter. Formation of big percolation cluster may change the properties of the medium, e.g., it could lead to the changing its transparency. This could be used to get a signal of the intermediate baryonic system formation. We consider two signals to identify the formation of the intermediate baryon systems: the critical changing of transparency of the strongly interacting matter and the enhancement of light nuclei production with increase in centrality.

  20. Did the Solar System form in a sequential triggered star formation event?

    E-Print Network [OSTI]

    Parker, Richard J

    2015-01-01

    The presence and abundance of the short-lived radioisotopes (SLRs) $^{26}$Al and $^{60}$Fe during the formation of the Solar System is difficult to explain unless the Sun formed in the vicinity of one or more massive star(s) that exploded as supernovae. Two different scenarios have been proposed to explain the delivery of SLRs to the protosolar nebula: (i) direct pollution of the protosolar disc by supernova ejecta and (ii) the formation of the Sun in a sequential star formation event in which supernovae shockwaves trigger further star formation which is enriched in SLRs. The sequentially triggered model has been suggested as being more astrophysically likely than the direct pollution scenario. In this paper we investigate this claim by analysing a combination of $N$-body and SPH simulations of star formation. We find that sequential star formation would result in large age spreads (or even bi-modal age distributions for spatially coincident events) due to the dynamical relaxation of the first star-formation ...

  1. Soliton communication lines based on spectrally efficient modulation formats

    SciTech Connect (OSTI)

    Yushko, O V; Redyuk, A A

    2014-06-30

    We report the results of mathematical modelling of optical-signal propagation in soliton fibre-optic communication lines (FOCLs) based on spectrally efficient signal modulation formats. We have studied the influence of spontaneous emission noise, nonlinear distortions and FOCL length on the data transmission quality. We have compared the characteristics of a received optical signal for soliton and conventional dispersion compensating FOCLs. It is shown that in the presence of strong nonlinearity long-haul soliton FOCLs provide a higher data transmission performance, as well as allow higher order modulation formats to be used as compared to conventional communication lines. In the context of a coherent data transmission, soliton FOCLs allow the use of phase modulation with many levels, thereby increasing the spectral efficiency of the communication line. (optical communication lines)

  2. Cluster formation probability in the trans-tin and trans-lead nuclei

    E-Print Network [OSTI]

    K. P. Santhosh; R. K. Biju; Sabina Sahadevan

    2010-05-10

    Within our fission model, the Coulomb and proximity potential model (CPPM) cluster formation probabilities are calculated for different clusters ranging from carbon to silicon for the parents in the trans-tin and trans- lead regions. It is found that in trans-tin region the 12^C, 16^O, 20^Ne and 24^Mg clusters have maximum cluster formation probability and lowest half lives as compared to other clusters. In trans-lead region the 14^C, 18, 20^O, 23^F, 24,26^Ne, 28,30^Mg and 34^Si clusters have the maximum cluster formation probability and minimum half life, which show that alpha like clusters are most probable for emission from trans-tin region while non-alpha clusters are probable from trans-lead region. These results stress the role of neutron proton symmetry and asymmetry of daughter nuclei in these two cases.

  3. Photo-heating and supernova feedback amplify each other's effect on the cosmic star formation rate

    E-Print Network [OSTI]

    Andreas H. Pawlik; Joop Schaye

    2009-03-17

    Photo-heating associated with reionisation and kinetic feedback from core-collapse supernovae have previously been shown to suppress the high-redshift cosmic star formation rate. Here we investigate the interplay between photo-heating and supernova feedback using a set of cosmological, smoothed particle hydrodynamics simulations. We show that photo-heating and supernova feedback mutually amplify each other's ability to suppress the star formation rate. Our results demonstrate the importance of the simultaneous, non-independent inclusion of these two processes in models of galaxy formation to estimate the strength of the total negative feedback they exert. They may therefore be of particular relevance to semi-analytic models in which the effects of photo-heating and supernova feedback are implicitly assumed to act independently of each other.

  4. Non-intrusive characterization of heat transfer fluid aerosol formation 

    E-Print Network [OSTI]

    Krishna, Kiran

    2001-01-01

    in process equipment. Predictive models relating the aerosol formation distances, aerosol droplet size, and volume concentrations to bulk liquid pressure, temperature, fluid properties, leak size and ambient conditions are developed. These models will be used...

  5. Notes on Star Formation

    E-Print Network [OSTI]

    Krumholz, Mark R

    2015-01-01

    This book provides an introduction to the field of star formation at a level suitable for graduate students or advanced undergraduates in astronomy or physics. The structure of the book is as follows. The first two chapters begin with a discussion of observational techniques, and the basic phenomenology they reveal. The goal is to familiarize students with the basic techniques that will be used throughout, and to provide a common vocabulary for the rest of the book. The next five chapters provide a similar review of the basic physical processes that are important for star formation. Again, the goal is to provide a basis for what follows. The remaining chapters discuss star formation over a variety of scales, starting with the galactic scale and working down to the scales of individual stars and their disks. The book concludes with a brief discussion of the clearing of disks and the transition to planet formation. The book includes five problem sets, complete with solutions.

  6. Rapid gas hydrate formation process

    DOE Patents [OSTI]

    Brown, Thomas D.; Taylor, Charles E.; Unione, Alfred J.

    2013-01-15

    The disclosure provides a method and apparatus for forming gas hydrates from a two-phase mixture of water and a hydrate forming gas. The two-phase mixture is created in a mixing zone which may be wholly included within the body of a spray nozzle. The two-phase mixture is subsequently sprayed into a reaction zone, where the reaction zone is under pressure and temperature conditions suitable for formation of the gas hydrate. The reaction zone pressure is less than the mixing zone pressure so that expansion of the hydrate-forming gas in the mixture provides a degree of cooling by the Joule-Thompson effect and provides more intimate mixing between the water and the hydrate-forming gas. The result of the process is the formation of gas hydrates continuously and with a greatly reduced induction time. An apparatus for conduct of the method is further provided.

  7. Controlled Irradiative Formation of Penitentes

    E-Print Network [OSTI]

    V. Bergeron; C. Berger; M. D. Betterton

    2006-01-24

    Spike-shaped structures are produced by light-driven ablation in very different contexts. Penitentes 1-4 m high are common on Andean glaciers, where their formation changes glacier dynamics and hydrology. Laser ablation can produce cones 10-100 microns high with a variety of proposed applications in materials science. We report the first laboratory generation of centimeter-scale snow and ice penitentes. Systematically varying conditions allows identification of the essential parameters controlling the formation of ablation structures. We demonstrate that penitente initiation and coarsening requires cold temperatures, so that ablation leads to sublimation rather than melting. Once penitentes have formed, further growth of height can occur by melting. The penitentes intially appear as small structures (3 mm high) and grow by coarsening to 1-5 cm high. Our results are an important step towards understanding and controlling ablation morphologies.

  8. Maximization of permanent trapping of CO{sub 2} and co-contaminants in the highest-porosity formations of the Rock Springs Uplift (Southwest Wyoming): experimentation and multi-scale modeling

    SciTech Connect (OSTI)

    Piri, Mohammad

    2014-03-31

    Under this project, a multidisciplinary team of researchers at the University of Wyoming combined state-of-the-art experimental studies, numerical pore- and reservoir-scale modeling, and high performance computing to investigate trapping mechanisms relevant to geologic storage of mixed scCO{sub 2} in deep saline aquifers. The research included investigations in three fundamental areas: (i) the experimental determination of two-­?phase flow relative permeability functions, relative permeability hysteresis, and residual trapping under reservoir conditions for mixed scCO{sub 2}-­?brine systems; (ii) improved understanding of permanent trapping mechanisms; (iii) scientifically correct, fine grid numerical simulations of CO{sub 2} storage in deep saline aquifers taking into account the underlying rock heterogeneity. The specific activities included: (1) Measurement of reservoir-­?conditions drainage and imbibition relative permeabilities, irreducible brine and residual mixed scCO{sub 2} saturations, and relative permeability scanning curves (hysteresis) in rock samples from RSU; (2) Characterization of wettability through measurements of contact angles and interfacial tensions under reservoir conditions; (3) Development of physically-­?based dynamic core-­?scale pore network model; (4) Development of new, improved high-­? performance modules for the UW-­?team simulator to provide new capabilities to the existing model to include hysteresis in the relative permeability functions, geomechanical deformation and an equilibrium calculation (Both pore-­? and core-­?scale models were rigorously validated against well-­?characterized core-­? flooding experiments); and (5) An analysis of long term permanent trapping of mixed scCO{sub 2} through high-­?resolution numerical experiments and analytical solutions. The analysis takes into account formation heterogeneity, capillary trapping, and relative permeability hysteresis.

  9. Search results | Department of Energy

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    Enter terms Search Showing 21 - 30 of 24 results. Download Modeling the Process of Mining Silicon Through a Single DisplacementRedox Reaction As the popularity of photovoltaic...

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

    Enter terms Search Showing 21 - 30 of 25 results. Download Modeling the Process of Mining Silicon Through a Single DisplacementRedox Reaction As the popularity of photovoltaic...

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    Enter terms Search Showing 21 - 30 of 23 results. Download Modeling the Process of Mining Silicon Through a Single DisplacementRedox Reaction As the popularity of photovoltaic...

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

    Enter terms Search Showing 31 - 40 of 32 results. Download Modeling the Process of Mining Silicon Through a Single DisplacementRedox Reaction As the popularity of photovoltaic...

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    Enter terms Search Showing 31 - 40 of 34 results. Download Modeling the Process of Mining Silicon Through a Single DisplacementRedox Reaction As the popularity of photovoltaic...

  14. Search results | Department of Energy

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

    Enter terms Search Showing 41 - 50 of 60 results. Download Modeling the Process of Mining Silicon Through a Single DisplacementRedox Reaction As the popularity of photovoltaic...

  15. Star formation relations in nearby molecular clouds

    SciTech Connect (OSTI)

    Evans, Neal J. II; Heiderman, Amanda; Vutisalchavakul, Nalin

    2014-02-20

    We test some ideas for star formation relations against data on local molecular clouds. On a cloud by cloud basis, the relation between the surface density of star formation rate and surface density of gas divided by a free-fall time, calculated from the mean cloud density, shows no significant correlation. If a crossing time is substituted for the free-fall time, there is even less correlation. Within a cloud, the star formation rate volume and surface densities increase rapidly with the corresponding gas densities, faster than predicted by models using the free-fall time defined from the local density. A model in which the star formation rate depends linearly on the mass of gas above a visual extinction of 8 mag describes the data on these clouds, with very low dispersion. The data on regions of very massive star formation, with improved star formation rates based on free-free emission from ionized gas, also agree with this linear relation.

  16. Analytical results for the four-loop RG functions in the 2D non-linear O(n) ?-model on the lattice

    E-Print Network [OSTI]

    O. Veretin

    2013-06-12

    We recalculate four-loop renormalization group functions in 2-dimensional nonlinear O(n) {\\sigma}-model using coordinate-space method. The high accuracy of calculation allow us to find the analytical form of {\\beta}- and {\\gamma}-function (anomaluos dimension).

  17. RESRAD-BUILD: A computer model for analyzing the radiological doses resulting from the remediation and occupancy of buildings contaminated with radioactive material

    SciTech Connect (OSTI)

    Yu, C.; LePoire, D.J.; Jones, L.G. [and others

    1994-11-01

    The RESRAD-BUILD computer code is a pathway analysis model designed to evaluate the potential radiological dose incurred by an individual who works or lives in a building contaminated with radioactive material. The transport of radioactive material inside the building from one compartment to another is calculated with an indoor air quality model. The air quality model considers the transport of radioactive dust particulates and radon progeny due to air exchange, deposition and resuspension, and radioactive decay and ingrowth. A single run of the RESRAD-BUILD code can model a building with up to: three compartments, 10 distinct source geometries, and 10 receptor locations. A shielding material can be specified between each source-receptor pair for external gamma dose calculations. Six exposure pathways are considered in the RESRAD-BUILD code: (1) external exposure directly from the source; (2) external exposure to materials deposited on the floor; (3) external exposure due to air submersion; (4) inhalation of airborne radioactive particulates; (5) inhalation of aerosol indoor radon progeny; and (6) inadvertent ingestion of radioactive material, either directly from the sources or from materials deposited on the surfaces of the building compartments. 4 refs., 23 figs., 4 tabs.

  18. Stochastic opinion formation in scale-free networks

    SciTech Connect (OSTI)

    M. Bartolozzi; D. B. Leinweber; A. W. Thomas

    2005-10-01

    The dynamics of opinion formation in large groups of people is a complex nonlinear phenomenon whose investigation is just beginning. Both collective behavior and personal views play an important role in this mechanism. In the present work we mimic the dynamics of opinion formation of a group of agents, represented by two states 1, as a stochastic response of each agent to the opinion of his/her neighbors in the social network and to feedback from the average opinion of the whole. In the light of recent studies, a scale-free Barabsi-Albert network has been selected to simulate the topology of the interactions. A turbulent-like dynamics, characterized by an intermittent behavior, is observed for a certain range of the model parameters. The problem of uncertainty in decision taking is also addressed both from a topological point of view, using random and targeted removal of agents from the network, and by implementing a three-state model, where the third state, zero, is related to the information available to each agent. Finally, the results of the model are tested against the best known network of social interactions: the stock market. A time series of daily closures of the Dow-Jones index has been used as an indicator of the possible applicability of our model in the financial context. Good qualitative agreement is found.

  19. Formation of adhesion domains in stressed and confined membranes

    E-Print Network [OSTI]

    Dharan, Nadiv

    2015-01-01

    The adhesion bonds connecting a lipid bilayer to an underlying surface may undergo a condensation transition resulting from an interplay between a short range attractive potential between them, and a long range fluctuation-induced potential of mean force. Here, we use computer simulations of a coarse-grained molecular model of supported lipid bilayers to study this transition in confined membranes, and in membranes subjected to a non-vanishing surface tension. Our results show that confinement may alter significantly the condensation transition of the adhesion bonds, whereas the application of surface tension has a very minor effect on it. We also investigate domain formation in membranes under negative tension which, in free membranes, causes enhancement of the amplitude of the membrane thermal undulations. Our results indicate that in supported membranes, this effect of a negative surface tension on the fluctuation spectrum is largely eliminated by the pressure resulting from the mixing entropy of the adhes...

  20. Search results | Department of Energy

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

    results Enter terms Search Showing 1 - 1 of 1 result. Download Modeling the Process of Mining Silicon Through a Single DisplacementRedox Reaction As the popularity of photovoltaic...

  1. Statistical characteristic of the initial exciton number n/sub 0/ and its influence on the results in the exciton model

    SciTech Connect (OSTI)

    MIAO Rong-Zhi; WU Guo-Hua; ZENG Wei-Han; LIU Jian-Ye; YU Chao-Fan; YU Xian

    1985-10-01

    It is assumed that the initial exciton number n/sub 0/ is statistical. The expression of the probability h(n/sub 0/) for any probable n/sub 0/ is given. The theoretical calculation results, including the energy spectra and the double differential cross sections, are obtained by weighted summation of the contributions coming from various probable n/sub 0/. The agreement between experimental data and the theoretical results is quite good.

  2. A New Two-Moment Bulk Stratiform Cloud Microphysics Scheme in the Community Atmosphere Model, Version 3 (CAM3). Part II: Single-Column and Global Results

    SciTech Connect (OSTI)

    Gettelman, A.; Morrison, H.; Ghan, Steven J.

    2008-08-11

    The global performance of a new 2-moment cloud microphysics scheme for a General Circulation Model (GCM) is presented and evaluated relative to observations. The scheme produces reasonable representations of cloud particle size and number concentration when compared to observations, and represents expected and observed spatial variations in cloud microphysical quantities. The scheme has smaller particles and higher number concentrations over land than the standard bulk microphysics in the GCM, and is able to balance the radiation budget of the planet with 60% the liquid water of the standard scheme, in better agreement with observations. The new scheme treats both the mixing ratio and number concentration of rain and snow, and is therefore able to differentiate the two key regimes, consisting of drizzle in shallow warm clouds and larger rain drops in deeper cloud systems. The modeled rain and snow size distributions are consistent with observations.

  3. An updated analysis of Inert Higgs Doublet Model in light of the recent results from LUX, PLANCK, AMS-02 and LHC

    SciTech Connect (OSTI)

    Arhrib, Abdesslam; Tsai, Yue-Lin Sming; Yuan, Tzu-Chiang; Yuan, Qiang E-mail: yue-lin.tsai@ipmu.jp E-mail: tcyuan@phys.sinica.edu.tw

    2014-06-01

    In light of the recent discovery by the ATLAS and CMS experiments at the Large Hadron Collider (LHC) of a Higgs-like particle with a narrow mass range of 125–126 GeV, we perform an updated analysis on one of the popular scalar dark matter models, the Inert Higgs Doublet Model (IHDM). We take into account in our likelihood analysis of various experimental constraints, including recent relic density measurement, dark matter direct and indirect detection constraints as well as the latest collider constraints on the invisible decay width of the Higgs boson and monojet search at the LHC. It is shown that if the invisible decay of the standard model Higgs boson is open, LHC as well as direct detection experiments like LUX and XENON100 could put stringent limits on the Higgs boson couplings to dark matter. We find that the most favoured parameter space for IHDM corresponds to dark matter with a mass less than 100 GeV or so. In particular, the best-fit points are at the dark matter mass around 70 GeV where the invisible Higgs decay to dark matter is closed. Scalar dark matter in the higher mass range of 0.5–4 TeV is also explored in our study. Projected sensitivities for the future experiments of monojet at LHC-14, XENON1T and AMS-02 one year antiproton flux are shown to put further constraints on the existing parameter space of IHDM.

  4. Formation of charmonium states in heavy ion collisions and thermalization of charm

    E-Print Network [OSTI]

    R. L. Thews

    2006-04-06

    We examine the possibility to utilize in-medium charmonium formation in heavy ion interactions at collider energy as a probe of the properties of the medium. This is possible because the formation process involves recombination of charm quarks which imprints a signal on the resulting normalized transverse momentum distribution containing information about the momentum distribution of the quarks. We have contrasted the transverse momentum spectra of J/Psi, characterized by , which result from the formation process in which the charm quark distributions are taken at opposite limits with regard to thermalization in the medium. The first uses charm quark distributions unchanged from their initial production in a pQCD process, appropriate if their interaction with the medium is negligible. The second uses charm quark distributions which are in complete thermal equilibrium with the transversely expanding medium, appropriate if a very strong interaction between charm quarks and medium exists. We find that the resulting of the formed J/Psi should allow one to differentiate between these extremes, and that this differentiation is not sensitive to variations in the detailed dynamics of in-medium formation. We include a comparison of predictions of this model with preliminary PHENIX measurements, which indicates compatibility with a substantial fraction of in-medium formation.

  5. 41EurASEAA 2006, Bougon papers Natural processes iNvolved iN the formatioN of

    E-Print Network [OSTI]

    Boyer, Edmond

    site formation processes. A sedimentological study indicated that the fossiliferous layer resulted from

  6. NEWS & VIEWS PATTERN FORMATION

    E-Print Network [OSTI]

    Loss, Daniel

    no apologies for investing energy into problems of specific application to a particular process in nature, and having the curiosity to want to find out how they work. The general public, and especially children flow/surface growth system in a rarely explored region of parameter space for such pattern formation

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

    SciTech Connect (OSTI)

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

    2012-12-20

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

  8. 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...

  9. Lisburne Formation fracture characterization and flow modeling 

    E-Print Network [OSTI]

    Karpov, Alexandre Valerievich

    2001-01-01

    Evaluation of fractured reservoirs for fluid flow and optimal well placement is often very complicated. In general, fractures enhance permeability and increase access to matrix surface, but their random aspects create difficulties for analysis...

  10. Mark formation model for optical rewritable PROEFSCHRIFT

    E-Print Network [OSTI]

    Vuik, Kees

    the laser beam during recording. Furthermore, these discs consist of various layers. High power laser pulses rewritable recording. Dissertation at Delft University of Technology. Copyright c 2007 by J.H. Brusche The work described in this thesis was financially supported by the Nether- lands Technology Foundation (STW

  11. Star Formation History of Omega Centauri Imprinted in Elemental Abundance Patterns

    E-Print Network [OSTI]

    Takuji Tsujimoto; Toshikazu Shigeyama

    2003-02-15

    The star formation history of the globular cluster Omega Centauri is investigated in the context of an inhomogeneous chemical evolution model in which supernovae induce star formation. The proposed model explains recent observations for Omega Cen stars, and divides star formation into three epochs. At the end of the first epoch, ~ 70% of the gas was expelled by supernovae. AGB stars then supplied s-process elements to the remaining gas during the first interval of ~300 Myr. This explains the observed sudden increase in Ba/Fe ratios in Omega Cen stars at [Fe/H] ~ -1.6. Supernovae at the end of the second epoch were unable to expel the gas. Eventually, Type Ia supernovae initiated supernova-induced star formation, and remaining gas was stripped when the cluster passed through the newly formed disk of the Milky Way. The formation of Omega Cen is also discussed in the framework of globular cluster formation triggered by cloud-cloud collisions. In this scenario, the relative velocity of clouds in the collision determines the later chemical evolution in the clusters. A head-on collision of proto-cluster clouds with a low relative velocity would have converted less than 1% of gas into stars and promoted the subsequent chemical evolution by supernova-driven star formation. This is consistent with present observed form of Omega Cen. In contrast, the other Galactic globular clusters are expected to have formed from more intense head-on collisions, and the resultant clouds would have been too thin for supernovae to accumulate enough gas to form the next generation of stars. This explains the absence of chemical evolution in these other globular clusters.

  12. Interoperability format translation and transformation between IFC architectural design file and simulation file formats

    DOE Patents [OSTI]

    Chao, Tian-Jy; Kim, Younghun

    2015-01-06

    Automatically translating a building architecture file format (Industry Foundation Class) to a simulation file, in one aspect, may extract data and metadata used by a target simulation tool from a building architecture file. Interoperability data objects may be created and the extracted data is stored in the interoperability data objects. A model translation procedure may be prepared to identify a mapping from a Model View Definition to a translation and transformation function. The extracted data may be transformed using the data stored in the interoperability data objects, an input Model View Definition template, and the translation and transformation function to convert the extracted data to correct geometric values needed for a target simulation file format used by the target simulation tool. The simulation file in the target simulation file format may be generated.

  13. Interoperability format translation and transformation between IFC architectural design file and simulation file formats

    DOE Patents [OSTI]

    Chao, Tian-Jy; Kim, Younghun

    2015-02-03

    Automatically translating a building architecture file format (Industry Foundation Class) to a simulation file, in one aspect, may extract data and metadata used by a target simulation tool from a building architecture file. Interoperability data objects may be created and the extracted data is stored in the interoperability data objects. A model translation procedure may be prepared to identify a mapping from a Model View Definition to a translation and transformation function. The extracted data may be transformed using the data stored in the interoperability data objects, an input Model View Definition template, and the translation and transformation function to convert the extracted data to correct geometric values needed for a target simulation file format used by the target simulation tool. The simulation file in the target simulation file format may be generated.

  14. Coulomb effects on the formation of proton halo nuclei

    E-Print Network [OSTI]

    Yu-Jie Liang; Yan-Song Li; Fu-Guo Deng; Xi-Han Li; Bao-An Bian; Feng-Shou Zhang; Zu-Hua Liu; Hong-Yu Zhou

    2007-08-01

    The exotic structures in the 2s_{1/2} states of five pairs of mirror nuclei ^{17}O-^{17}F, ^{26}Na-^{26}P, ^{27}Mg-^{27}P, ^{28}Al-^{28}P and ^{29}Si-^{29}P are investigated with the relativistic mean-field (RMF) theory and the single-particle model (SPM) to explore the role of the Coulomb effects on the proton halo formation. The present RMF calculations show that the exotic structure of the valence proton is more obvious than that of the valence neutron of its mirror nucleus, the difference of exotic size between each mirror nuclei becomes smaller with the increase of mass number A of the mirror nuclei and the ratios of the valence proton and valence neutron root-mean-square (RMS) radius to the matter radius in each pair of mirror nuclei all decrease linearly with the increase of A. In order to interpret these results, we analyze two opposite effects of Coulomb interaction on the exotic structure formation with SPM and find that the contribution of the energy level shift is more important than that of the Coulomb barrier for light nuclei. However, the hindrance of the Coulomb barrier becomes more obvious with the increase of A. When A is larger than 34, Coulomb effects on the exotic structure formation will almost become zero because its two effects counteract with each other.

  15. Emptiness Formation Probability

    E-Print Network [OSTI]

    Nicholas Crawford; Stephen Ng; Shannon Starr

    2014-12-30

    We present rigorous upper and lower bounds on the emptiness formation probability for the ground state of a spin-$1/2$ Heisenberg XXZ quantum spin system. For a $d$-dimensional system we find a rate of decay of the order $\\exp(-c L^{d+1})$ where $L$ is the sidelength of the box in which we ask for the emptiness formation event to occur. In the $d=1$ case this confirms previous predictions made in the integrable systems community, though our bounds do not achieve the precision predicted by Bethe ansatz calculations. On the other hand, our bounds in the case $d \\geq 2$ are new. The main tools we use are reflection positivity and a rigorous path integral expansion which is a variation on those previously introduced by Toth, Aizenman-Nachtergaele and Ueltschi.

  16. Formate-assisted pyrolysis

    DOE Patents [OSTI]

    DeSisto, William Joseph; Wheeler, Marshall Clayton; van Heiningen, Adriaan R. P.

    2015-03-17

    The present invention provides, among other thing, methods for creating significantly deoxygenated bio-oils form biomass including the steps of providing a feedstock, associating the feedstock with an alkali formate to form a treated feedstock, dewatering the treated feedstock, heating the dewatered treated feedstock to form a vapor product, and condensing the vapor product to form a pyrolysis oil, wherein the pyrolysis oil contains less than 30% oxygen by weight.

  17. Dark-ages reionization & galaxy formation simulation IV: UV luminosity functions of high-redshift galaxies

    E-Print Network [OSTI]

    Liu, Chuanwu; Angel, P W; Duffy, Alan R; Geil, Paul M; Poole, Gregory B; Mesinger, Andrei; Wyithe, J Stuart B

    2015-01-01

    In this paper we present calculations of the UV luminosity function predictions from the Dark-ages Reionization And Galaxy-formation Observables from Numerical Simulations (DRAGONS) project, which combines N-body, semi-analytic and semi-numerical modeling designed to study galaxy formation during the Epoch of Reionization. Using galaxy formation physics including supernova feedback, the model naturally reproduces the UV LFs for high-redshift star-forming galaxies from $z{\\sim}5$ through to $z{\\sim}10$. We investigate the predicted luminosity-star formation rate (SFR) relation, finding that variable SFR histories of galaxies result in a scatter around the mean relation of $0.1$-$0.3$ dex depending on UV luminosity. We find close agreement between the model and observationally derived SFR functions. We use our predicted luminosities to investigate the luminosity function below current detection limits, and the ionizing photon budget for reionization. We predict that the slope of the UV LF remains steep below cu...

  18. Thickness-dependent secondary structure formation of tubelike polymers

    E-Print Network [OSTI]

    Janke, Wolfhard

    OFFPRINT Thickness-dependent secondary structure formation of tubelike polymers T. Vogel, T.epljournal.org doi: 10.1209/0295-5075/85/10003 Thickness-dependent secondary structure formation of tubelike polymers the conformational phase diagram of a simple model for flexible polymers with explicit thickness. The thickness

  19. (Non) formation of methanol by direct hydrogenation of formate on copper catalysts

    SciTech Connect (OSTI)

    Yang, Yong; Mims, Charles A.; Disselkamp, Robert S.; Kwak, Ja Hun; Peden, Charles HF; Campbell, C. T.

    2010-10-14

    We have attempted to hydrogenate adsorbed formate species on copper catalysts to probe the importance of this postulated mechanistic step in methanol synthesis. Surface formate coverages up to 0.25 were produced at temperatures between 413K and 453K on supported (Cu/SiO2) copper and unsupported copper catalysts. The adlayers were produced by various methods including (1) steady state catalytic conditions in CO2-H2 (3:1, 6 bar) atmospheres, and (2) by exposure of the catalysts to formic acid. As reported in earlier work, the catalytic surface at steady state contains bidentate formate species with coverages up to saturation levels of ~ 0.25 at the low temperatures of this study. The reactivity of these formate adlayers was investigated at relevant reaction temperatures in atmospheres containing up to 6 bar H2 partial pressure by simultaneous mass spectrometry (MS) and infrared (IR) spectroscopy measurements. The yield of methanol during the attempted hydrogenation (“titration”) of these adlayers was insignificant (<0.2 mol % of the formate adlayer) even in dry hydrogen partial pressures up to 6 bar. Hydrogen titration of formate species produced from formic acid also failed to produce significant quantities of methanol, and attempted titration in gases consisting of CO-hydrogen mixtures or dry CO2 were also unproductive. The formate decomposition kinetics, measured by IR, were also unaffected by these changes in the gas composition. Similar experiments on unsupported copper also failed to show any methanol. From these results, we conclude that methanol synthesis on copper cannot result from the direct hydrogenation of (bidentate) formate species in simple steps involving adsorbed H species alone. Furthermore, experiments performed on both supported (Cu/SiO2) and unsupported copper catalysts gave similar results implying that the methanol synthesis reaction mechanism only involves metal surface chemistry. Pre-exposure of the bidentate formate adlayer to oxidation by O2 or N2O produces a change to a monodentate configuration. Attempted titration of this monodentate formate/O coadsorbed layer in dry hydrogen produces significant quantities of methanol, although decomposition of formate to carbon dioxide and hydrogen remains the dominant reaction pathway. Simultaneous production of water is also observed during this titration as the copper surface is re-reduced. These results indicate that co-adsorbates related to surface oxygen or water-derived species may be critical to methanol production on copper, perhaps assisting in the hydrogenation of adsorbed formate to adsorbed methoxyl.

  20. Formation of Cyanoformaldehyde in the interstellar space

    E-Print Network [OSTI]

    Das, Ankan; Chakrabarti, Sandip K; Saha, Rajdeep; Chakrabarti, Sonali

    2013-01-01

    Cyanoformaldehyde (HCOCN) molecule has recently been suspected towards the Sagittarius B2(N) by the Green Bank telescope, though a confirmation of this observation has not yet been made. In and around a star forming region, this molecule could be formed by the exothermic reaction between two abundant interstellar species, H$_2$CO and CN. Till date, the reaction rate coefficient for the formation of this molecule is unknown. Educated guesses were used to explain the abundance of this molecule by chemical modeling. In this paper, we carried out quantum chemical calculations to find out empirical rate coefficients for the formation of HCOCN and different chemical properties during the formation of HCOCN molecules. Though HCOCN is stable against unimolecular decomposition, this gas phase molecule could be destroyed by many other means, like: ion-molecular reactions or by the effect of cosmic rays. Ion-molecular reaction rates are computed by using the capture theories. We have also included the obtained rate coef...

  1. Petroleum Engineering 321 Formation Evaluation

    E-Print Network [OSTI]

    measurements to estimate hydrocarbon reserves and petrophysical properties of the formation such as porosity Description: Introduction to well-log interpretation for formation evaluation of hydrocarbon, net pay thickness, water/hydrocarbon saturation, permeability, and saturation-dependent capillary

  2. Data from selected Almond Formation outcrops -- Sweetwater County, Wyoming

    SciTech Connect (OSTI)

    Jackson, S.R.; Rawn-Schatzinger, V.

    1993-12-01

    The objectives of this research program are to: (1) determine the reservoir characteristics and production problems of shoreline barrier reservoirs; and (2) develop methods and methodologies to effectively characterize shoreline barrier reservoirs to predict flow patterns of injected and produced fluids. Two reservoirs were selected for detailed reservoir characterization studies -- Bell Creek field, Carter County, Montana, that produces from the Lower Cretaceous (Albian-Cenomanian) Muddy Formation, and Patrick Draw field, Sweetwater County, Wyoming that produces from the Upper Cretaceous (Campanian) Almond Formation of the Mesaverde Group. An important component of the research project was to use information from outcrop exposures of the producing formations to study the spatial variations of reservoir properties and the degree to which outcrop information can be used in the construction of reservoir models. A report similar to this one presents the Muddy Formation outcrop data and analyses performed in the course of this study (Rawn-Schatzinger, 1993). Two outcrop localities, RG and RH, previously described by Roehler (1988) provided good exposures of the Upper Almond shoreline barrier facies and were studied during 1990--1991. Core from core well No. 2 drilled approximately 0.3 miles downdip of outcrop RG was obtained for study. The results of the core study will be reported in a separate volume. Outcrops RH and RG, located about 2 miles apart were selected for detailed description and drilling of core plugs. One 257-ft-thick section was measured at outcrop RG, and three sections {approximately}145 ft thick located 490 and 655 feet apart were measured at the outcrop RH. Cross-sections of these described profiles were constructed to determine lateral facies continuity and changes. This report contains the data and analyses from the studied outcrops.

  3. Explaining the formation of bulges with MOND

    E-Print Network [OSTI]

    Combes, F

    2015-01-01

    In the cold dark matter (CDM) paradigm, bulges easily form through galaxy mergers, either major or minor, or through clumpy disks in the early universe, where clumps are driven to the center by dynamical friction. Also pseudo-bulges, with a more disky morphology and kinematics, can form more slowly through secular evolution of a bar, where resonant stars are elevated out of the plane, in a peanut/box shape. As a result, in CDM cosmological simulations, it is very difficult to find a bulgeless galaxy, while they are observed very frequently in the local universe. A different picture emerges in alternative models of the missing mass problem. In MOND (MOdified Newtonian Dynamics), galaxy mergers are much less frequent, since the absence of dark matter halos reduces the dynamical friction between two galaxies. Also, while clumpy galaxies lead to rapid classical bulge formation in CDM, the inefficient dynamical friction with MOND in the early-universe galaxies prevents the clumps to coalesce together in the center...

  4. Search results | Department of Energy

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

    Enter terms Search Showing 11 - 20 of 12 results. Download Scale Models and Wind Turbines As wind turbines and wind farms become larger to take advantage of the economies of...

  5. Search results | Department of Energy

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

    Enter terms Search Showing 21 - 30 of 34 results. Download Scale Models and Wind Turbines As wind turbines and wind farms become larger to take advantage of the economies of...

  6. Search results | Department of Energy

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

    - 20 of 12 results. Download Scale Models and Wind Turbines As wind turbines and wind farms become larger to take advantage of the economies of scale and increased wind speeds at...

  7. Search results | Department of Energy

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

    - 30 of 35 results. Download Scale Models and Wind Turbines As wind turbines and wind farms become larger to take advantage of the economies of scale and increased wind speeds at...

  8. Search results | Department of Energy

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

    1 - 1 of 1 result. Download Scale Models and Wind Turbines As wind turbines and wind farms become larger to take advantage of the economies of scale and increased wind speeds at...

  9. Search results | Department of Energy

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

    - 30 of 34 results. Download Scale Models and Wind Turbines As wind turbines and wind farms become larger to take advantage of the economies of scale and increased wind speeds at...

  10. Search results | Department of Energy

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

    - 20 of 18 results. Download Scale Models and Wind Turbines As wind turbines and wind farms become larger to take advantage of the economies of scale and increased wind speeds at...

  11. Search results | Department of Energy

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

    - 20 of 19 results. Download Scale Models and Wind Turbines As wind turbines and wind farms become larger to take advantage of the economies of scale and increased wind speeds at...

  12. Search results | Department of Energy

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

    - 20 of 14 results. Download Scale Models and Wind Turbines As wind turbines and wind farms become larger to take advantage of the economies of scale and increased wind speeds at...

  13. Search results | Department of Energy

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

    Showing 51 - 60 of 59 results. Download Solar Cell Simulation Students model the flow of energy from the sun as it enters a photovoltaic cell, moves along a wire and powers a...

  14. Search results | Department of Energy

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

    Enter terms Search Showing 11 - 20 of 14 results. Download Scale Models and Wind Turbines As wind turbines and wind farms become larger to take advantage of the economies of...

  15. The Complexity of Rationalizing Network Formation Shankar Kalyanaraman

    E-Print Network [OSTI]

    Umans, Chris

    and the Inequality-SAT (I-SAT) problem. Finally and most significantly, we prove that an approximation version. Keywords-network formation games, rationalization, Jackson- Wolinsky model, Inequality-SAT, hardness

  16. Reservoir Characterization, Formation Evaluation, and 3D Geologic Modeling of the Upper Jurassic Smackover Microbial Carbonate Reservoir and Associated Reservoir Facies at Little Cedar Creek Field, Northeastern Gulf of Mexico 

    E-Print Network [OSTI]

    Al Haddad, Sharbel

    2012-10-19

    -carbonaceous facies of the Haynesville Formation. These carbonate reservoirs are composed of vuggy boundstone and moldic grainstone, and the petroleum trap is stratigraphic being controlled primarily by changes in depositional facies. To maximize recovery...

  17. Dynamics of precipitation pattern formation at geothermal hot springs

    E-Print Network [OSTI]

    Nigel Goldenfeld; Pak Yuen Chan; John Veysey

    2006-05-26

    We formulate and model the dynamics of spatial patterns arising during the precipitation of calcium carbonate from a supersaturated shallow water flow. The model describes the formation of travertine deposits at geothermal hot springs and rimstone dams of calcite in caves. We find explicit solutions for travertine domes at low flow rates, identify the linear instabilities which generate dam and pond formation on sloped substrates, and present simulations of statistical landscape evolution.

  18. Galactosynthesis: Halo Histories, Star Formation, and Disks

    E-Print Network [OSTI]

    Ari Buchalter; Raul Jimenez; Marc Kamionkowski

    2000-06-01

    We investigate the effects of a variety of ingredients that must enter into a realistic model for disk-galaxy formation, focusing primarily on the Tully-Fisher (TF) relation and its scatter in several wavebands. Our main findings are: (a) the slope, normalization, and scatter of the TF relation across various wavebands is determined {\\em both} by halo properties and star formation in the disk; (b) TF scatter owes primarily to the spread in formation redshifts. The scatter can be measurably reduced by chemical evolution, and also in some cases by the weak anti-correlation between peak height and spin; (c) multi-wavelength constraints can be important in distinguishing between models which appear to fit the TF relation in I or K; (d) successful models seem to require that the bulk of disk formation cannot occur too early (z>2) or too late (z<0.5), and are inconsistent with high values of $\\Omega_0$; (e) a realistic model with the above ingredients can reasonably reproduce the observed z=0 TF relation in {\\em all} bands (B, R, I, and K). It can also account for the z=1 B-band TF relation and yield rough agreement with the local B and K luminosity functions and B-band surface-brightness--magnitude relation. The remarkable agreement with observations suggests that the amount of gas that is expelled or poured into a disk galaxy must be small, and that the specific angular momentum of the baryons must roughly equal that of the halo; there is little room for angular momentum transfer. In an appendix we present analytic fits to stellar-population synthesis models.

  19. Dynamical Treatment of Virialization Heating in Galaxy Formation

    E-Print Network [OSTI]

    Peng Wang; Tom Abel

    2007-09-11

    In a hierarchical picture of galaxy formation virialization continually transforms gravitational potential energy into kinetic energies of the baryonic and dark matter. For the gaseous component the kinetic, turbulent energy is transformed eventually into internal thermal energy through shocks and viscous dissipation. Traditionally this virialization and shock heating has been assumed to occur instantaneously allowing an estimate of the gas temperature to be derived from the the virial temperature defined from the embedding dark matter halo velocity dispersion. As the mass grows the virial temperature of a halo grows. Mass accretion hence can be translated into a heating term. We derive this heating rate from the extended Press Schechter formalism and demonstrate its usefulness in semi-analytical models of galaxy formation. Our method explicitly conserves energy unlike the previous impulsive heating assumptions. Our formalism can trivially be applied in all current semi-analytical models as the heating term can be computed directly from the underlying merger trees. Our analytic results for the first cooling halos and the transition from cold to hot accretion are in agreement with numerical simulations.

  20. Formation of helical ion chains

    E-Print Network [OSTI]

    Ramil Nigmatullin; Adolfo del Campo; Gabriele De Chiara; Giovanna Morigi; Martin B. Plenio; Alex Retzker

    2015-08-25

    We study the nonequilibrium dynamics of the linear to zigzag structural phase transition exhibited by an ion chain confined in a trap with periodic boundary conditions. The transition is driven by reducing the transverse confinement at a finite quench rate, which can be accurately controlled. This results in the formation of zigzag domains oriented along different transverse planes. The twists between different domains can be stabilized by the topology of the trap and under laser cooling the system has a chance to relax to a helical chain with nonzero winding number. Molecular dynamics simulations are used to obtain a large sample of possible trajectories for different quench rates. The scaling of the average winding number with different quench rates is compared to the prediction of the Kibble-Zurek theory, and a good quantitative agreement is found.

  1. Where the Blue Stragglers Roam: Searching for a Link Between Formation and Environment

    E-Print Network [OSTI]

    Nathan Leigh; Alison Sills; Christian Knigge

    2008-08-15

    The formation of blue stragglers is still not completely understood, particularly the relationship between formation environment and mechanism. We use a large, homogeneous sample of blue stragglers in the cores of 57 globular clusters to investigate the relationships between blue straggler populations and their environments. We use a consistent definition of "blue straggler" based on position in the color-magnitude diagram, and normalize the population relative to the number of red giant branch stars in the core. We find that the previously determined anti-correlation between blue straggler frequency and total cluster mass is present in the purely core population. We find some weak correlations with central velocity dispersion and with half-mass relaxation time. The blue straggler frequency does not show any trend with any other cluster parameter. Even though collisions may be expected to be a dominant blue straggler formation process in globular cluster cores, we find no correlation between the frequency of blue stragglers and the collision rate in the core. We also investigated the blue straggler luminosity function shape, and found no relationship between any cluster parameter and the distribution of blue stragglers in the color-magnitude diagram. Our results are inconsistent with some recent models of blue straggler formation that include collisional formation mechanisms, and may suggest that almost all observed blue stragglers are formed in binary systems.

  2. S-102 Transfer Pump Restriction Modeling Results

    SciTech Connect (OSTI)

    Wells, Beric E.; Johnson, Kenneth I.; Rector, David R.; Trent, Donald S.

    2008-03-27

    It was determined that a radioactive waste leak in the Hanford S Farm in the vicinity of the S-102 retrieval pump discharge occurred because of over-pressurization and failure of the S-102 dilution water supply hose while operating the retrieval pump in reverse with an obstructed suction cavity and an unobstructed flow path to the dilution water supply hose. This report describes efforts to identify plausible scenarios for the waste leak to occur.

  3. Legrand BBBP Implementation Model Designed for Results 

    E-Print Network [OSTI]

    Horton, P.

    2013-01-01

    of Operation ? Turn OFF lights ? Plug in fork lifts 0 10 20 30 40 50 60 70 80 90 100 1 :1 5: 01 A M E D T 2 :0 0: 01 A M E D T 2 :4 5: 01 A M E D T 3 :3 0: 01 A M E D T 4 :1 5: 01 A M E D... M E D T 1 0: 15 :0 1 P M E D T 1 1: 00 :0 1 P M E D T 1 1: 45 :0 1 P M E D T 1 2: 30 :0 1 A M E D T Distribution Center Lighting and Battery Submeters April 16, 2013 Battery Lighting 1 :1 5...

  4. Rapid Formation of Gas Giant Planets around M Dwarf Stars

    E-Print Network [OSTI]

    Alan P. Boss

    2006-01-20

    Extrasolar planet surveys have begun to detect gas giant planets in orbit around M dwarf stars. While the frequency of gas giant planets around M dwarfs so far appears to be lower than that around G dwarfs, it is clearly not zero. Previous work has shown that the core accretion mechanism does not seem to be able to form gas giant planets around M dwarfs, because the time required for core formation scales with the orbital period, which lengthens for lower mass stars, resulting in failed (gas-poor) cores unless the gaseous protoplanetary disk survives for > 10 Myr. Disk instability, on the other hand, is rapid enough (~ 1000 yrs) that it should be able to form gas giant protoplanets around even low mass stars well before the gaseous disk disappears. A new suite of three dimensional radiative, gravitational hydrodynamical models is presented that calculates the evolution of initially marginally gravitationally unstable disks with masses of 0.021 to 0.065 solar masses orbiting around stars with masses of 0.1 and 0.5 solar masses, respectively. The models show that gas giant planets are indeed likely to form by the disk instability mechanism in orbit around M dwarf stars, the opposite of the prediction for formation by the core accretion mechanism. This difference offers another observational test for discriminating between these two theoretical end members for giant planet formation. Ongoing and future extrasolar planet searches around M dwarfs by spectroscopy, microlensing, photometry, and astrometry offer the opportunity to help decide between the dominance of the two mechanisms.

  5. Physical Constraints on Geologic CO2 Sequestration in Low-Volume Basalt Formations

    SciTech Connect (OSTI)

    Ryan M. Pollyea; Jerry P. Fairley; Robert K. Podgorney; Travis L. McLing

    2014-03-01

    Deep basalt formations within large igneous provinces have been proposed as target reservoirs for carbon capture and sequestration on the basis of favorable CO2-water-rock reaction kinetics that suggest carbonate mineralization rates on the order of 102–103 d. Although these results are encouraging, there exists much uncertainty surrounding the influence of fracture-controlled reservoir heterogeneity on commercial-scale CO2 injections in basalt formations. This work investigates the physical response of a low-volume basalt reservoir to commercial-scale CO2 injections using a Monte Carlo numerical modeling experiment such that model variability is solely a function of spatially distributed reservoir heterogeneity. Fifty equally probable reservoirs are simulated using properties inferred from the deep eastern Snake River Plain aquifer in southeast Idaho, and CO2 injections are modeled within each reservoir for 20 yr at a constant mass rate of 21.6 kg s–1. Results from this work suggest that (1) formation injectivity is generally favorable, although injection pressures in excess of the fracture gradient were observed in 4% of the simulations; (2) for an extensional stress regime (as exists within the eastern Snake River Plain), shear failure is theoretically possible for optimally oriented fractures if Sh is less than or equal to 0.70SV; and (3) low-volume basalt reservoirs exhibit sufficient CO2 confinement potential over a 20 yr injection program to accommodate mineral trapping rates suggested in the literature.

  6. Formation mechanism and properties of CdS-Ag2S nanorod superlattices

    SciTech Connect (OSTI)

    Wang, Lin-Wang; Demchenko, Denis O.; Robinson, Richard D.; Sadtler, Bryce; Erdonmez, Can K.; Alivisatos, A. Paul; Wang, Lin-Wang

    2008-08-11

    The mechanism of formation of recently fabricated CdS-Ag{sub 2}S nanorod superlattices is considered and their elastic properties are predicted theoretically based on experimental structural data. We consider different possible mechanisms for the spontaneous ordering observed in these 1D nanostructures, such as diffusion-limited growth and ordering due to epitaxial strain. A simplified model suggests that diffusion-limited growth partially contributes to the observed ordering, but cannot account for the full extent of the ordering alone. The elastic properties of bulk Ag{sub 2}S are predicted using a first principles method and are fed into a classical valence force field (VFF) model of the nanostructure. The VFF results show significant repulsion between Ag{sub 2}S segments, strongly suggesting that the interplay between the chemical interface energy and strain due to the lattice mismatch between the two materials drives the spontaneous pattern formation.

  7. Essays on Network Formation 

    E-Print Network [OSTI]

    Mueller, William Graham

    2012-10-19

    are examined and I determine what networks, if any, each model may converge to in the limit. The long-run behavior of each model is examined through the use of simulations and compared to one another. I find that amount and type of information agents have...

  8. Latest Electroweak Results from CDF

    SciTech Connect (OSTI)

    Lancaster, Mark

    2010-05-01

    The latest results in electroweak physics from proton anti-proton collisions at the Fermilab Tevatron recorded by the CDF detector are presented. The results provide constraints on parton distribution functions, the mass of the Higgs boson and beyond the Standard Model physics.

  9. Significant primordial star formation at redshifts z ~ 3-4

    E-Print Network [OSTI]

    Raul Jimenez; Zoltan Haiman

    2006-02-27

    Four recent observational results have challenged our understanding of high--redshift galaxies, as they require the presence of far more ultraviolet photons than should be emitted by normal stellar populations. First, there is significant ultraviolet emission from Lyman Break Galaxies (LBGs) at wavelenghts shorter than 912\\AA. Second, there is strong Lyman alpha emission from extended ``blobs'' with little or no associated apparent ionizing continuum. Third, there is a population of galaxies with unusually strong Lyman-alpha emission lines. And fourth, there is a strong HeII (1640 \\AA) emission line in a composite of LBGs. The proposed explanations for the first three observations are internally inconsistent, and the fourth puzzle has remained hitherto unexplained. Here we show that all four problems are resolved simultaneously if 10-30 percent of the stars in many galaxies at z ~ 3-4 are mainly primordial - unenriched by elements heavier than helium ('metals'). Most models of hierarchical galaxy formation assume efficient intra--galactic metal mixing, and therefore do not predict metal-free star formation at redshifts significantly below z ~5. Our results imply that micro-mixing of metals within galaxies is inefficient on a ~ Gyr time-scale, a conclusion that can be verified with higher resolution simulations, and future observations of the HeII emission line.

  10. Reservoir architecture modeling: Nonstationary models for quantitative geological characterization. Final report, April 30, 1998

    SciTech Connect (OSTI)

    Kerr, D.; Epili, D.; Kelkar, M.; Redner, R.; Reynolds, A.

    1998-12-01

    The study was comprised of four investigations: facies architecture; seismic modeling and interpretation; Markov random field and Boolean models for geologic modeling of facies distribution; and estimation of geological architecture using the Bayesian/maximum entropy approach. This report discusses results from all four investigations. Investigations were performed using data from the E and F units of the Middle Frio Formation, Stratton Field, one of the major reservoir intervals in the Gulf Coast Basin.

  11. Hawaii demand-side management resource assessment. Final report, Reference Volume 3 -- Residential and commercial sector DSM analyses: Detailed results from the DBEDT DSM assessment model; Part 1, Technical potential

    SciTech Connect (OSTI)

    1995-04-01

    The Hawaii Demand-Side Management Resource Assessment was the fourth of seven projects in the Hawaii Energy Strategy (HES) program. HES was designed by the Department of Business, Economic Development, and Tourism (DBEDT) to produce an integrated energy strategy for the State of Hawaii. The purpose of Project 4 was to develop a comprehensive assessment of Hawaii`s demand-side management (DSM) resources. To meet this objective, the project was divided into two phases. The first phase included development of a DSM technology database and the identification of Hawaii commercial building characteristics through on-site audits. These Phase 1 products were then used in Phase 2 to identify expected energy impacts from DSM measures in typical residential and commercial buildings in Hawaii. The building energy simulation model DOE-2.1E was utilized to identify the DSM energy impacts. More detailed information on the typical buildings and the DOE-2.1E modeling effort is available in Reference Volume 1, ``Building Prototype Analysis``. In addition to the DOE-2.1E analysis, estimates of residential and commercial sector gas and electric DSM potential for the four counties of Honolulu, Hawaii, Maui, and Kauai through 2014 were forecasted by the new DBEDT DSM Assessment Model. Results from DBEDTs energy forecasting model, ENERGY 2020, were linked with results from DOE-2.1E building energy simulation runs and estimates of DSM measure impacts, costs, lifetime, and anticipated market penetration rates in the DBEDT DSM Model. Through its algorithms, estimates of DSM potential for each forecast year were developed. Using the load shape information from the DOE-2.1E simulation runs, estimates of electric peak demand impacts were developed. Numerous tables and figures illustrating the technical potential for demand-side management are included.

  12. Silica diagenesis in Monterey Formation: controls and application

    SciTech Connect (OSTI)

    Kablanow, R.I. II

    1987-05-01

    The factors controlling diagenesis of biogenic silica (opal-A to opal-CT to quartz) in the Monterey Formation of California has been an ongoing subject of study. The accepted concept proposes that a high detrital content inhibits the opal-A to opal-CT reaction, whereas it accelerates the opal-CT to quartz reaction. Others have suggested that clay minerals directly influence the rate of silica transformation by the adsorption of silica from solution. It is proposed that the primary control on silica diagenesis is the thermal regime of the basin. Important variables which influence the temperature development include time, sediment accumulation rate, burial depth, porosity, thermal conductivity, temperature of silica phase change, and heat flow. The Miocene Monterey Formation had fairly rapid sedimentation rates which produced a thick section of fine-grained sediments (up to 13,000 ft, 4 km, in the Salinas basin). As these sediments underwent progressive burial, both compaction and silica transformation reduced porosity, resulting in an increase in thermal conductivity. To simulate the thermal, depositional, and diagenetic events, detailed thermal models were used. These models clearly reflect the difference in the geologic history observed between the Huasna, Pismo, and Salinas basins. The thermal models used in this study strongly confirm that silica diagenesis is primarily dependent on the temperature structure of a basin and that any catalytic influence which detrital minerals may have on silica diagenesis is a second-order effect and does not alter the regional reaction boundaries. These models can also be used as powerful tools in hydrocarbon exploration by providing a clearer picture of the thermal development of the basin.

  13. Galaxy Formation and Evolution. II. Energy Balance, Star Formation and Feed-back

    E-Print Network [OSTI]

    Fulvio Buonomo; Giovanni Carraro; Cesare Chiosi; Cesario Lia

    1999-09-13

    In this paper we present a critical discussion of the algorithms commonly used in N-body simulations of Galaxy Formation to deal with the energy equation governing heating and cooling, to model star formation and the star formation rate, and to account for energy feed-back from stars. First, we propose our technique for solving the energy equation in presence of heating and cooling, which includes some difference with respect to the standard semi-implicit technique. Second, we examine the current criteria for the onset of the star formation activity. We suggest a new approach, in which star formaiton is let depend on the total mass density - baryonic (gas and stars) and dark matter - of the system and on the metal-dependent cooling efficiency. Third, we check and discuss the separate effects of energy (and mass) feed-back from several sources - namely supernovae, stellar winds from massive stars, and UV flux from the same objects. All the simulations are performed in the framework of the formation and evolution of a disk galaxy. We show that the inclusion of these physical phenomena has a signigicant impact on the evolution of the galaxy model.

  14. Chaos in Terrestrial Planet Formation

    E-Print Network [OSTI]

    Volker Hoffmann; Simon L. Grimm; Ben Moore; Joachim Stadel

    2015-08-04

    Terrestrial planets are thought to be the result of a vast number of gravitational interactions and collisions between smaller bodies. We use numerical simulations to show that practically identical initial conditions result in a wide array of final planetary configurations. This highly chaotic behaviour questions the predictability of different scenarios for the formation and evolution of our solar system and planetary systems in general. However, multiple realisations of the same initial conditions can be used to predict certain global statistics. We present two sets of numerical experiments that quantify this behaviour. Firstly, we demonstrate that simulations with slightly displaced particles are completely divergent after ~500 years, irrespective of initial displacement, particle number, and code accuracy. If a single planetesimal is moved by less than one millimetre, then a different set of planets results -- this timescale for chaotic divergence decreases with increasing particle number. Secondly, we show final planetary configurations of initially similar simulations with and without giant planets after evolving them for ~148 Myr. We find that the same simulations including giant planets tend to generate higher mass planets at lower semi-major axes than simulations without gas giants. This prediction can be tested with forthcoming observational programs. By extracting outliers in the observations, we cautiously predict that Kepler-10, Kepler-9, 61 Vir, HD 134060, and HD 51608 may host as yet undetected giant planets.

  15. FORMULATION OF NON-STEADY-STATE DUST FORMATION PROCESS IN ASTROPHYSICAL ENVIRONMENTS

    SciTech Connect (OSTI)

    Nozawa, Takaya [Kavli Institute for the Physics and Mathematics of the Universe (WPI), University of Tokyo, Kashiwa, Chiba 277-8583 (Japan); Kozasa, Takashi, E-mail: takaya.nozawa@ipmu.jp [Department of Cosmosciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810 (Japan)

    2013-10-10

    The non-steady-state formation of small clusters and the growth of grains accompanied by chemical reactions are formulated under the consideration that the collision of key gas species (key molecule) controls the kinetics of dust formation process. The formula allows us to evaluate the size distribution and condensation efficiency of dust formed in astrophysical environments. We apply the formulation to the formation of C and MgSiO{sub 3} grains in the ejecta of supernovae, as an example, to investigate how the non-steady effect influences the formation process, condensation efficiency f{sub con,{sub ?}}, and average radius a{sub ave,{sub ?}} of newly formed grains in comparison with the results calculated with the steady-state nucleation rate. We show that the steady-state nucleation rate is a good approximation if the collision timescale of key molecule ?{sub coll} is much smaller than the timescale ?{sub sat} with which the supersaturation ratio increases; otherwise the effect of the non-steady state becomes remarkable, leading to a lower f{sub con,{sub ?}} and a larger a{sub ave,{sub ?}}. Examining the results of calculations, we reveal that the steady-state nucleation rate is applicable if the cooling gas satisfies ? ? ?{sub sat}/?{sub coll} ?> 30 during the formation of dust, and find that f{sub con,{sub ?}} and a{sub ave,{sub ?}} are uniquely determined by ?{sub on} at the onset time t{sub on} of dust formation. The approximation formulae for f{sub con,{sub ?}} and a{sub ave,{sub ?}} as a function of ?{sub on} could be useful in estimating the mass and typical size of newly formed grains from observed or model-predicted physical properties not only in supernova ejecta but also in mass-loss winds from evolved stars.

  16. NETL Report format template

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

    Ursa Field: A Process-Response Model to Explain a Classic Wireline Log Signature. Deep-Water Reservoirs of the World. GCSSEPM Foundation 20 th Annual Research Conference, 2000; p...

  17. Lithium abundances in exoplanet host stars as test of planetary formation scenarii

    E-Print Network [OSTI]

    M. Castro; O. Richard; S. Vauclair

    2005-10-20

    Following the observations of Israelian et al. 2004, we compare different evolutionary models in order to study the lithium destruction processes and the planetary formation scenarii.

  18. Characterising the acceleration phase of blast wave formation

    SciTech Connect (OSTI)

    Fox, T. E. Pasley, J.; Robinson, A. P. L.; Schmitz, H.

    2014-10-15

    Intensely heated, localised regions in uniform fluids will rapidly expand and generate an outwardly propagating blast wave. The Sedov-Taylor self-similar solution for such blast waves has long been studied and applied to a variety of scenarios. A characteristic time for their formation has also long been identified using dimensional analysis, which by its very nature, can offer several interpretations. We propose that, rather than simply being a characteristic time, it may be interpreted as the definitive time taken for a blast wave resulting from an intense explosion in a uniform media to contain its maximum kinetic energy. A scaling relation for this measure of the acceleration phase, preceding the establishment of the blast wave, is presented and confirmed using a 1D planar hydrodynamic model.

  19. On star formation in primordial protoglobular clouds

    E-Print Network [OSTI]

    Paolo Padoan; Raul Jimenez; Bernard Jones

    1996-04-11

    Using a new physical model for star formation (Padoan 1995) we have tested the possibility that globular clusters (GCs) are formed from primordial mass fluctuations, whose mass scale ($10^8$ - $10^9$ M$_{\\odot}$) is selected out of a CDM spectrum by the mechanism of non-equilibrium formation of $H_2$. We show that such clouds are able to convert about 0.003 of their total mass into a bound system (GC) and about 0.02 into halo stars. The metal enriched gas is dispersed away from the GC by supernova explosions and forms the galactic disk. These mass ratios between GCs, halo and disk depend on the predicted IMF which is a consequence of the universal statistics of fluid turbulence. They also depend on the ratio of baryonic over non-baryonic mass ,$X_b$, and are comparable with the values observed in typical spiral galaxies for $X_b \\approx 0.1-0.2$. The computed mass and radius for a GC ( $5\\times 10^5$ M$_{\\odot}$ and 30 pc) are in good agreement with the average values in the Galaxy. The model predicts an exponential cut off in the stellar IMF below 0.1 M$_{\\odot}$ in GCs and 0.6 M$_{\\odot}$ in the halo. The quite massive star formation in primordial clouds leads to a large number of supernovae and to a high blue luminosity during the first two Gyr of the life of every galaxy.

  20. Changes in the halo formation rates due to features in the primordial spectrum

    SciTech Connect (OSTI)

    Hazra, Dhiraj Kumar, E-mail: dhiraj@apctp.org [Harish-Chandra Research Institute, Chhatnag Road, Jhunsi, Allahabad 211019 (India)

    2013-03-01

    Features in the primordial scalar power spectrum provide a possible roadway to describe the outliers at the low multipoles in the WMAP data. Apart from the CMB angular power spectrum, these features can also alter the matter power spectrum and, thereby, the formation of the large scale structure. Carrying out a complete numerical analysis, we investigate the effects of primordial features on the formation rates of the halos. We consider a few different inflationary models that lead to features in the scalar power spectrum and an improved fit to the CMB data, and analyze the corresponding imprints on the formation of halos. Performing a Markov Chain Monte Carlo analysis with the WMAP seven year data and the SDSS halo power spectrum from LRG DR7 for the models of our interest, we arrive at the parameter space of the models allowed by the data. We illustrate that, inflationary potentials, such as the quadratic potential with sinusoidal modulations and the axion monodromy model, which generate certain repeated, oscillatory features in the inflationary perturbation spectrum, do not induce a substantial difference in the number density of halos at their best fit values, when compared with, say, a nearly scale invariant spectrum as is generated by the standard quadratic potential. However, we find that the number density and the formation rates of halos change by about 13–22% for halo masses ranging over 10{sup 4}–10{sup 14} M{sub s}un, for potential parameters that lie within 2-? around the best fit values arrived at from the aforesaid joint constraints. We briefly discuss the implications of our results.

  1. DAMAGE AND ROCKVOLATILE MIXTURE EFFECTS ON IMPACT CRATER FORMATION

    E-Print Network [OSTI]

    Stewart, Sarah T.

    DAMAGE AND ROCK­VOLATILE MIXTURE EFFECTS ON IMPACT CRATER FORMATION JOHN D. O'KEEFE, SARAH T models for material damage, dilatancy, and inhomogeneous materials (mixtures). We found that a strength degradation (damage) model was necessary to produce faulting in homogeneous materials. Both normal and thrust

  2. Formation of Secondary Containment Systems Using Permeation of Colloidal Silica

    E-Print Network [OSTI]

    Zornberg, Jorge G.

    the tanks. This study evaluates the formation of hydraulic barriers for secondary containment through the permeation of colloidal silica grout. A sim- plified infiltration model is presented to predict the downward. Because the simplified infiltration model cannot predict the soil-grout interaction or the permeation

  3. Star formation histories in early-type galaxies

    E-Print Network [OSTI]

    D. Thomas

    1998-08-24

    I discuss the formation of alpha-enhanced metal-rich stellar populations in the nuclei of luminous ellipticals. Based on hierarchical clustering, different galaxy formation scenarios, which imply different star formation histories, are considered. In contrast to the fast clumpy collapse mode, the late merger of two spiral galaxies fails to reproduce significantly $\\alpha$-enhanced abundance ratios, unless the IMF is flattened. Following the star formation history predicted by semi-analytic models of hierarchical clustering for the average elliptical, solar abundance ratios are obtained with Salpeter IMF. According to the models, bright ellipticals in the field are expected to have significantly lower Mg/Fe ratios than their counterparts in a cluster.

  4. Masers and star formation

    E-Print Network [OSTI]

    Vincent L. Fish

    2007-04-02

    Recent observational and theoretical advances concerning astronomical masers in star forming regions are reviewed. Major masing species are considered individually and in combination. Key results are summarized with emphasis on present science and future prospects.

  5. A Look At Three Different Scenarios for Bulge Formation

    E-Print Network [OSTI]

    Rychard J. Bouwens; Laura Cayon; Joseph Silk

    1998-12-10

    In this paper, we present three qualitatively different scenarios for bulge formation: a secular evolution model in which bulges form after disks and undergo several central starbursts, a primordial collapse model in which bulges and disks form simultaneously, and an early bulge formation model in which bulges form prior to disks. We normalize our models to the local z=0 observations of de Jong & van der Kruit (1994) and Peletier & Balcells (1996) and make comparisons with high redshift observations. We consider model predictions relating directly to bulge-to-disk properties. As expected, smaller bulge-to-disk ratios and bluer bulge colors are predicted by the secular evolution model at all redshifts, although uncertainties in the data are currently too large to differentiate strongly between the models.

  6. Semantic Enrichment for Building Information Modeling

    E-Print Network [OSTI]

    Belsky, Michael; Sacks, Rafael; Brilakis, Ioannis

    2015-01-01

    developed that can infer such relationships from the geometry and spatial topology. Tools such as Siemens Synchronous Technology (Siemens), for example, can use data from multiple CAD systems. Given a model in B- rep the tools can process it into a feature... models are usually generated in heterogeneous computing platforms and as a result the semantics are hidden in information structures of different product data formats. This imposes difficulties for seamless interoperability and efficient reuse...

  7. In situ secondary organic aerosol formation from ambient pine forest air using an oxidation flow reactor

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

    Palm, B. B.; Campuzano-Jost, P.; Ortega, A. M.; Day, D. A.; Kaser, L.; Jud, W.; Karl, T.; Hansel, A.; Hunter, J. F.; Cross, E. S.; et al

    2015-11-04

    Ambient air was oxidized by OH radicals in an oxidation flow reactor (OFR) located in a montane pine forest during the BEACHON-RoMBAS campaign to study biogenic secondary organic aerosol (SOA) formation and aging. High OH concentrations and short residence times allowed for semi-continuous cycling through a large range of OH exposures ranging from hours to weeks of equivalent (eq.) atmospheric aging. A simple model is derived and used to account for the relative time scales of condensation of low volatility organic compounds (LVOCs) onto particles, condensational loss to the walls, and further reaction to produce volatile, non-condensing fragmentation products. Moremore »SOA production was observed in the OFR at nighttime (average 4 ?g m-3 when LVOC fate corrected) compared to daytime (average 1 ?g m-3 when LVOC fate corrected), with maximum formation observed at 0.4–1.5 eq. days of photochemical aging. SOA formation followed a similar diurnal pattern to monoterpenes, sesquiterpenes, and toluene + p-cymene concentrations, including a substantial increase just after sunrise at 07:00 LT. Higher photochemical aging (> 10 eq. days) led to a decrease in new SOA formation and a loss of preexisting OA due to heterogeneous oxidation followed by fragmentation and volatilization. When comparing two different commonly used methods of OH production in OFRs (OFR185 and OFR254), similar amounts of SOA formation were observed. We recommend the OFR185 mode for future forest studies. Concurrent gas-phase measurements of air after OH oxidation illustrate the decay of primary VOCs, production of small oxidized organic compounds, and net production at lower ages followed by net consumption of terpenoid oxidation products as photochemical age increased. New particle formation was observed in the reactor after oxidation, especially during times when precursor gas concentrations and SOA formation were largest. Approximately 6 times more SOA was formed in the reactor from OH oxidation than could be explained by the VOCs measured in ambient air. Several recently-developed instruments quantified ambient semi- and intermediate-volatility organic compounds (S/IVOCs) that were not detected by a PTR-TOF-MS. An SOA yield of 24–80 % from those compounds can explain the observed SOA, suggesting that these typically unmeasured S/IVOCs play a substantial role in ambient SOA formation. Our results allow ruling out condensation sticking coefficients much lower than 1. Our measurements help clarify the magnitude of SOA formation in forested environments, and demonstrate methods for interpretation of ambient OFR measurements.« less

  8. Introduction Main Result

    E-Print Network [OSTI]

    Yan, Catherine Huafei

    Introduction Main Result Enumeration Crossings and Nestings of Two Edges in Set Partitions Yan Crossings and Nestings of Set Partitions #12;Introduction Main Result Enumeration Definition} Catherine Yan Crossings and Nestings of Set Partitions #12;Introduction Main Result Enumeration Definition

  9. Cleanroom energy benchmarking results

    E-Print Network [OSTI]

    Tschudi, William; Xu, Tengfang

    2001-01-01

    emeu/consumption) Cleanroom benchmarking results, (http://Fok, and P. Rumsey. 2001. Cleanroom Energy Benchmarking inin the proceedings. Cleanroom Energy Benchmarking Results

  10. Recent Results in AdS/QCD

    E-Print Network [OSTI]

    Joshua Erlich

    2008-12-29

    AdS/QCD is an extra-dimensional approach to modeling the light hadronic resonances in QCD. AdS/QCD models are generally successful at reproducing low-energy observables with around 10-20% accuracy, depending on the details of the model. We discuss the motivation for these models, their intrinsic limitations, and some recent results.

  11. Star Formation and Metallicity History of the SDSS galaxy survey: unlocking the fossil record

    E-Print Network [OSTI]

    Benjamin Panter; Alan F. Heavens; Raul Jimenez

    2003-08-12

    Using MOPED we determine non-parametrically the star-formation and metallicity history of over 37,000 high-quality galaxy spectra from the Sloan Digital Sky Survey (SDSS) early data release. We use the entire spectral range, rather than concentrating on specific features, and we estimate the complete star formation history without prior assumptions about its form (by constructing so-called `population boxes'). The main results of this initial study are that the star formation rate in SDSS galaxies has been in decline for ~6 Gyr; a metallicity distribution for star-forming gas which is peaked ~3 Gyr ago at about solar metallicity, inconsistent with closed-box models, but consistent with infall models. We also determine the infall rate of gas in SDSS and show that it has been significant for the last 3 Gyr. We investigate errors using a Monte-Carlo Markov Chain algorithm. Further, we demonstrate that recovering star formation and metallicity histories for such a large sample becomes intractable without data compression methods, particularly the exploration of the likelihood surface. By exploring the whole likelihood surface we show that age-metallicity degeneracies are not as severe as by using only a few spectral features. We find that 65% of galaxies contain a significant old population (with an age of at least 8 Gyr), including recent starburst galaxies, and that over 97% have some stars older than 2 Gyr. It is the first time that the past star formation history has been determined from the fossil record of the present-day spectra of galaxies.

  12. CHEMICAL SIGNATURE OF A MAJOR MERGER IN THE EARLY FORMATION OF THE SMALL MAGELLANIC CLOUD

    SciTech Connect (OSTI)

    Tsujimoto, Takuji [National Astronomical Observatory, Mitaka-shi, Tokyo 181-8588 (Japan); Bekki, Kenji [School of Physics, University of New South Wales, Sydney 2052, NSW (Australia)], E-mail: taku.tsujimoto@nao.ac.jp

    2009-08-01

    The formation history of the Small Magellanic Cloud (SMC) is unraveled based on the results of our new chemical evolution models constructed for the SMC, highlighting the observed anomaly in the age-metallicity relation for star clusters in the SMC. We first propose that evidence of a major merger is imprinted in the age-metallicity relation as a dip in [Fe/H]. Our models predict that the major merger with a mass ratio of 1:1 to 1:4 occurred at {approx}7.5 Gyr ago, with a good reproduction of the abundance distribution function of field stars in the SMC. Furthermore, our models predict a relatively large scatter in [Mg/Fe] for -1.4 {<=} [Fe/H] {<=} -1.1 as a reflection of a looping feature resulting from the temporally inverse progress of chemical enrichment, which can be tested against future observational results. Given that the observed velocity dispersion ({approx}30 km s{sup -1}) of the SMC is much smaller than that ({approx}160 km s{sup -1}) of the Galactic halo, our finding strongly implies that the predicted merger event happened in a small group environment that was far from the Galaxy and contained a number of small gas-rich dwarfs comparable to the SMC. This theoretical view is extensively discussed in the framework that considers a connection with the formation history of the Large Magellanic Cloud.

  13. Definitions Main Result

    E-Print Network [OSTI]

    Heubach, Silvia

    Background Definitions Main Result Special Types of Patterns Summary Avoidance of partially ordered Avoidance of partially ordered patterns in compositions #12;Background Definitions Main Result Special Types of Patterns Summary Outline 1 Background 2 Definitions 3 Main Result Preliminaries Main Result 4 Special Types

  14. The role of stellar relaxation in the formation and evolution of the first massive black holes

    E-Print Network [OSTI]

    Yajima, Hidenobu

    2015-01-01

    We present calculations on the formation of massive black holes with 10^5 Msun at z > 6 that can be the seeds of supermassive black holes at z > 6. Under the assumption of compact star cluster formation in merging galaxies, star clusters in haloes of 10^8 ~ 10^9 Msun undergo rapid core-collapse leading to the formation of very massive stars (VMSs) with ~1000 Msun which directly collapse into black holes with similar masses. Star clusters in halos of > 10^9 Msun experience type-II supernovae before the formation of VMSs due to long core-collapse time scales. We also model the subsequent growth of black holes via accretion of residual stars in clusters. 2-body relaxation efficiently re-fills the loss cones of stellar orbits at larger radii and resonant relaxation at small radii is the main driver for accretion of stars onto black holes. As a result, more than ninety percent of stars in the initial cluster are swallowed by the central black holes before z=6. Using dark matter merger trees we derive black hole ma...

  15. Uncovering Fundamental Ash-Formation Mechanisms and Potential Means to Control the Impact on DPF Performance and Engine Efficiency

    Broader source: Energy.gov [DOE]

    Results illustrate ash particle growth and formation pathways, and influence of lubricant chemistry and exhaust conditions on fundamental ash properties

  16. Diagenesis and clay mineral formation at Gale Crater, Mars

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

    Bridges, J. C.; Schwenzer, S. P.; Leveille, R.; Westall, F.; Wiens, R. C.; Mangold, N.; Bristow, T.; Edwards, P.; Berger, G.

    2015-01-18

    The Mars Science Laboratory rover Curiosity found host rocks of basaltic composition and alteration assemblages containing clay minerals at Yellowknife Bay, Gale Crater. On the basis of the observed host rock and alteration minerals, we present results of equilibrium thermochemical modeling of the Sheepbed mudstones of Yellowknife Bay in order to constrain the formation conditions of its secondary mineral assemblage. Building on conclusions from sedimentary observations by the Mars Science Laboratory team, we assume diagenetic, in situ alteration. The modeling shows that the mineral assemblage formed by the reaction of a CO?-poor and oxidizing, dilute aqueous solution (Gale Portage Water)more »in an open system with the Fe-rich basaltic-composition sedimentary rocks at 10–50°C and water/rock ratio (mass of rock reacted with the starting fluid) of 100–1000, pH of ~7.5–12. Model alteration assemblages predominantly contain phyllosilicates (Fe-smectite, chlorite), the bulk composition of a mixture of which is close to that of saponite inferred from Chemistry and Mineralogy data and to that of saponite observed in the nakhlite Martian meteorites and terrestrial analogues. To match the observed clay mineral chemistry, inhomogeneous dissolution dominated by the amorphous phase and olivine is required. We therefore deduce a dissolving composition of approximately 70% amorphous material, with 20% olivine, and 10% whole rock component.« less

  17. Spectral Formation in X-Ray Pulsar Accretion Columns

    E-Print Network [OSTI]

    Peter A. Becker; Michael T. Wolff

    2005-03-03

    We present the first self-consistent model for the dynamics and the radiative transfer occurring in bright X-ray pulsar accretion columns, with a special focus on the role of the shock in energizing the emerging X-rays. The pressure inside the accretion column of a luminous X-ray pulsar is dominated by the photons, and consequently the equations describing the coupled radiative-dynamical structure must be solved simultaneously. Spectral formation in these sources is therefore a complex, nonlinear phenomenon. We obtain the analytical solution for the Green's function describing the upscattering of monochromatic radiation injected into the column from the thermal mound located near the base of the flow. The Green's function is convolved with a Planck distribution to model the X-ray spectrum resulting from the reprocessing of blackbody photons produced in the thermal mound. These photons diffuse through the infalling gas and eventually escape out the walls of the column, forming the observed X-ray spectrum. We show that the resulting column-integrated, phase-averaged spectrum has a power-law shape at high energies and a blackbody shape at low energies, in agreement with the observational data for many X-ray pulsars.

  18. Treating tar sands formations with karsted zones

    DOE Patents [OSTI]

    Vinegar, Harold J. (Bellaire, TX); Karanikas, John Michael (Houston, TX)

    2010-03-09

    Methods for treating a tar sands formation are described herein. The tar sands formation may have one or more karsted zones. Methods may include providing heat from one or more heaters to one or more karsted zones of the tar sands formation to mobilize fluids in the formation. At least some of the mobilized fluids may be produced from the formation.

  19. Effects of the UV background radiation on galaxy formation

    E-Print Network [OSTI]

    Masahiro Nagashima; Naoteru Gouda; Norimasa Sugiura

    1999-06-10

    We investigate the effects of the UV background radiation on galaxy formation by using the semi-analytic model including the photoionization process. The semi-analytic model is based on Cole et al. (1994) and we use almost the same parameters of their `fiducial' model. We find that the UV background mainly affects the formation of dwarf galaxies. Because of the suppression of star formation, the number density of small objects corresponding to dwarf galaxies decreases compared to the case of no UV radiation when the UV background exists until the present epoch. When the UV background vanishes at a low redshift, the number density of small objects is hardly changed but the colour becomes bluer, compared to the case of no UV radiation, because stars are newly formed after the UV background vanishes. On the other hand, the UV radiation hardly affects massive galaxies. This is because the massive galaxies are formed by mergers of small galaxies.

  20. Use-driven concept formation

    E-Print Network [OSTI]

    Roberts, Jennifer M. (Jennifer Marie)

    2010-01-01

    When faced with a complex task, humans often identify domain-specific concepts that make the task more tractable. In this thesis, I investigate the formation of domain-specific concepts of this sort. I propose a set of ...