Sample records for dense matter created

  1. Photons in dense nuclear matter: Random-phase approximation

    NASA Astrophysics Data System (ADS)

    Stetina, Stephan; Rrapaj, Ermal; Reddy, Sanjay

    2018-04-01

    We present a comprehensive and pedagogic discussion of the properties of photons in cold and dense nuclear matter based on the resummed one-loop photon self-energy. Correlations among electrons, muons, protons, and neutrons in β equilibrium that arise as a result of electromagnetic and strong interactions are consistently taken into account within the random phase approximation. Screening effects, damping, and collective excitations are systematically studied in a fully relativistic setup. Our study is relevant to the linear response theory of dense nuclear matter, calculations of transport properties of cold dense matter, and investigations of the production and propagation of hypothetical vector bosons such as the dark photons.

  2. Collaborative Research: Neutrinos & Nucleosynthesis in Hot Dense Matter

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Reddy, Sanjay

    2013-09-06

    It is now firmly established that neutrinos, which are copiously produced in the hot and dense core of the supernova, play a role in the supernova explosion mechanism and in the synthesis of heavy elements through a phenomena known as r-process nucleosynthesis. They are also detectable in terrestrial neutrino experiments, and serve as a probe of the extreme environment and complex dynamics encountered in the supernova. The major goal of the UW research activity relevant to this project was to calculate the neutrino interaction rates in hot and dense matter of relevance to core collapse supernova. These serve as keymore » input physics in large scale computer simulations of the supernova dynamics and nucleosynthesis being pursued at national laboratories here in the United States and by other groups in Europe and Japan. Our calculations show that neutrino production and scattering rate are altered by the nuclear interactions and that these modifications have important implications for nucleosynthesis and terrestrial neutrino detection. The calculation of neutrino rates in dense matter are difficult because nucleons in the dense matter are strongly coupled. A neutrino interacts with several nucleons and the quantum interference between scattering off different nucleons depends on the nature of correlations between them in dense matter. To describe these correlations we used analytic methods based on mean field theory and hydrodynamics, and computational methods such as Quantum Monte Carlo. We found that due to nuclear effects neutrino production rates at relevant temperatures are enhanced, and that electron neutrinos are more easily absorbed than anti-electron neutrinos in dense matter. The latter, was shown to favor synthesis of heavy neutron-rich elements in the supernova.« less

  3. Dense cold baryonic matter

    NASA Astrophysics Data System (ADS)

    Stavinskiy, A. V.

    2017-09-01

    A possibility of studying cold nuclear matter on the Nuclotron-NICA facility at baryonic densities characteristic of and higher than at the center of a neutron star is considered based on the data from cumulative processes. A special rare-event kinematic trigger for collisions of relativistic ions is proposed for effective selection of events accompanied by production of dense baryonic systems. Possible manifestations of new matter states under these unusual conditions and an experimental program for their study are discussed. Various experimental setups are proposed for these studies, and a possibility of using experimental setups at the Nuclotron-NICA facility for this purpose is considered.

  4. Dense matter in strong gravitational field of neutron star

    NASA Astrophysics Data System (ADS)

    Bhat, Sajad A.; Bandyopadhyay, Debades

    2018-02-01

    Mass, radius and moment of inertia are direct probes of compositions and Equation of State (EoS) of dense matter in neutron star interior. These are computed for novel phases of dense matter involving hyperons and antikaon condensate and their observable consequences are discussed in this article. Furthermore, the relationship between moment of inertia and quadrupole moment is also explored.

  5. Extreme ultraviolet interferometry of warm dense matter in laser plasmas.

    PubMed

    Gartside, L M R; Tallents, G J; Rossall, A K; Wagenaars, E; Whittaker, D S; Kozlová, M; Nejdl, J; Sawicka, M; Polan, J; Kalal, M; Rus, B

    2010-11-15

    We demonstrate that interferometric probing with extreme ultraviolet (EUV) laser light enables determination of the degree of ionization of the "warm dense matter" produced between the critical and ablation surfaces of laser plasmas. Interferometry has been utilized to measure both transmission and phase information for an EUV laser beam at the photon energy of 58.5 eV, probing longitudinally through laser-irradiated plastic (parylene-N) targets (thickness 350 nm) irradiated by a 300 ps duration pulse of wavelength 438 nm and peak irradiance 10(12) W cm(-2). The transmission of the EUV probe beam provides a measure of the rate of target ablation, as ablated plasma becomes close to transparent when the photon energy is less than the ionization energy of the predominant ion species. We show that refractive indices η below the solid parylene N (η(solid) = 0.946) and expected plasma values are produced in the warm dense plasma created by laser irradiation due to bound-free absorption in C(+).

  6. On parametrised cold dense matter equation of state inference

    NASA Astrophysics Data System (ADS)

    Riley, Thomas E.; Raaijmakers, Geert; Watts, Anna L.

    2018-04-01

    Constraining the equation of state of cold dense matter in compact stars is a major science goal for observing programmes being conducted using X-ray, radio, and gravitational wave telescopes. We discuss Bayesian hierarchical inference of parametrised dense matter equations of state. In particular we generalise and examine two inference paradigms from the literature: (i) direct posterior equation of state parameter estimation, conditioned on observations of a set of rotating compact stars; and (ii) indirect parameter estimation, via transformation of an intermediary joint posterior distribution of exterior spacetime parameters (such as gravitational masses and coordinate equatorial radii). We conclude that the former paradigm is not only tractable for large-scale analyses, but is principled and flexible from a Bayesian perspective whilst the latter paradigm is not. The thematic problem of Bayesian prior definition emerges as the crux of the difference between these paradigms. The second paradigm should in general only be considered as an ill-defined approach to the problem of utilising archival posterior constraints on exterior spacetime parameters; we advocate for an alternative approach whereby such information is repurposed as an approximative likelihood function. We also discuss why conditioning on a piecewise-polytropic equation of state model - currently standard in the field of dense matter study - can easily violate conditions required for transformation of a probability density distribution between spaces of exterior (spacetime) and interior (source matter) parameters.

  7. On parametrized cold dense matter equation-of-state inference

    NASA Astrophysics Data System (ADS)

    Riley, Thomas E.; Raaijmakers, Geert; Watts, Anna L.

    2018-07-01

    Constraining the equation of state of cold dense matter in compact stars is a major science goal for observing programmes being conducted using X-ray, radio, and gravitational wave telescopes. We discuss Bayesian hierarchical inference of parametrized dense matter equations of state. In particular, we generalize and examine two inference paradigms from the literature: (i) direct posterior equation-of-state parameter estimation, conditioned on observations of a set of rotating compact stars; and (ii) indirect parameter estimation, via transformation of an intermediary joint posterior distribution of exterior spacetime parameters (such as gravitational masses and coordinate equatorial radii). We conclude that the former paradigm is not only tractable for large-scale analyses, but is principled and flexible from a Bayesian perspective while the latter paradigm is not. The thematic problem of Bayesian prior definition emerges as the crux of the difference between these paradigms. The second paradigm should in general only be considered as an ill-defined approach to the problem of utilizing archival posterior constraints on exterior spacetime parameters; we advocate for an alternative approach whereby such information is repurposed as an approximative likelihood function. We also discuss why conditioning on a piecewise-polytropic equation-of-state model - currently standard in the field of dense matter study - can easily violate conditions required for transformation of a probability density distribution between spaces of exterior (spacetime) and interior (source matter) parameters.

  8. Scale-chiral symmetry, ω meson, and dense baryonic matter

    NASA Astrophysics Data System (ADS)

    Ma, Yong-Liang; Rho, Mannque

    2018-05-01

    It is shown that explicitly broken scale symmetry is essential for dense skyrmion matter in hidden local symmetry theory. Consistency with the vector manifestation fixed point for the hidden local symmetry of the lowest-lying vector mesons and the dilaton limit fixed point for scale symmetry in dense matter is found to require that the anomalous dimension (|γG2| ) of the gluon field strength tensor squared (G2 ) that represents the quantum trace anomaly should be 1.0 ≲|γG2|≲3.5 . The magnitude of |γG2| estimated here will be useful for studying hadron and nuclear physics based on the scale-chiral effective theory. More significantly, that the dilaton limit fixed point can be arrived at with γG2≠0 at some high density signals that scale symmetry can arise in dense medium as an "emergent" symmetry.

  9. Classical dense matter physics: some basic methods and results

    NASA Astrophysics Data System (ADS)

    Čelebonović, Vladan

    2002-07-01

    This is an introduction to the basic notions, some methods and open problems of dense matter physics and their applications in astrophysics. Experimental topics cover the range from the work of P. W. Bridgman to the discovery and basic results of use of the diamond anvil cell. On the theoretical side, the semiclassical method of P. Savić and R. Kašanin is described. The choice of these topics is conditioned by their applicability in astrophysics and the author's research experience. At the end of the paper is presented a list of some unsolved problems in dense matter physics and astrophysics, some (or all) of which could form a basis of future collaborations.

  10. Ultrafast X-Ray Absorption Spectroscopy of Isochorically Heated Warm Dense Matter

    NASA Astrophysics Data System (ADS)

    Engelhorn, Kyle Craig

    This dissertation will present a series of new tools, together with new techniques, focused on the understanding of warm and dense matter. We report on the development of a high time resolution and high detection efficiency x-ray camera. The camera is integrated with a short pulse laser and an x-ray beamline at the Advanced Light Source synchrotron. This provides an instrument for single shot, broadband x-ray absorption spectroscopy of warm and dense matter with 2 picosecond time resolution. Warm and dense matter is created by isochorically heating samples of known density with an ultrafast optical laser pulse, and X-ray absorption spectroscopy probes the unoccupied electronic density of states before the onset of hydrodynamic expansion and electron-ion equilibrium is reached. Measured spectra from a variety of materials are compared with first principle molecular dynamics and density functional theory calculations. In heated silicon dioxide spectra, two novel pre-edge features are observed, a peak below the band gap and absorption within the band gap, while a reduction was observed in the features above the edge. From consideration of the calculated spectra, the peak below the gap is attributed to valence electrons that have been promoted to the conduction band, the absorption within the gap is attributed to broken Si-O bonds, and the reduction above the edge is attributed to an elevated ionic temperature. In heated copper spectra, a time-dependent shift and broadening of the absorption edge are observed, consistent with and elevated electron temperature. The temporal evolution of the electronic temperature is accurately determined by fitting the measured spectra with calculated spectra. The electron-ion equilibration is studied with a two-temperature model. In heated nickel spectra, a shift of the absorption edge is observed. This shift is found to be inconsistent with calculated spectra and independent of incident laser fluence. A shift of the chemical potential

  11. Dense matter theory: A simple classical approach

    NASA Astrophysics Data System (ADS)

    Savić, P.; Čelebonović, V.

    1994-07-01

    In the sixties, the first author and by P. Savić and R. Kašanin started developing a mean-field theory of dense matter. It is based on the Coulomb interaction, supplemented by a microscopic selection rule and a set of experimentally founded postulates. Applications of the theory range from the calculation of models of planetary internal structure to DAC experiments.

  12. A strong diffusive ion mode in dense ionized matter predicted by Langevin dynamics

    DOE PAGES

    Mabey, P.; Richardson, S.; White, T. G.; ...

    2017-01-30

    We determined the state and evolution of planets, brown dwarfs and neutron star crusts by the properties of dense and compressed matter. Furthermore, due to the inherent difficulties in modelling strongly coupled plasmas, however, current predictions of transport coefficients differ by orders of magnitude. Collective modes are a prominent feature, whose spectra may serve as an important tool to validate theoretical predictions for dense matter. With recent advances in free electron laser technology, X-rays with small enough bandwidth have become available, allowing the investigation of the low-frequency ion modes in dense matter. Here, we present numerical predictions for these ionmore » modes and demonstrate significant changes to their strength and dispersion if dissipative processes are included by Langevin dynamics. Notably, a strong diffusive mode around zero frequency arises, which is not present, or much weaker, in standard simulations. These results have profound consequences in the interpretation of transport coefficients in dense plasmas.« less

  13. A strong diffusive ion mode in dense ionized matter predicted by Langevin dynamics

    PubMed Central

    Mabey, P.; Richardson, S.; White, T. G.; Fletcher, L. B.; Glenzer, S. H.; Hartley, N. J.; Vorberger, J.; Gericke, D. O.; Gregori, G.

    2017-01-01

    The state and evolution of planets, brown dwarfs and neutron star crusts is determined by the properties of dense and compressed matter. Due to the inherent difficulties in modelling strongly coupled plasmas, however, current predictions of transport coefficients differ by orders of magnitude. Collective modes are a prominent feature, whose spectra may serve as an important tool to validate theoretical predictions for dense matter. With recent advances in free electron laser technology, X-rays with small enough bandwidth have become available, allowing the investigation of the low-frequency ion modes in dense matter. Here, we present numerical predictions for these ion modes and demonstrate significant changes to their strength and dispersion if dissipative processes are included by Langevin dynamics. Notably, a strong diffusive mode around zero frequency arises, which is not present, or much weaker, in standard simulations. Our results have profound consequences in the interpretation of transport coefficients in dense plasmas. PMID:28134338

  14. Progress towards an ab initio real-time treatment of warm dense matter

    NASA Astrophysics Data System (ADS)

    Baczewski, Andrew; Cangi, Attila; Hansen, Stephanie; Jensen, Daniel

    2017-10-01

    Time-dependent density functional theory (TDDFT) provides an accurate description of equilibrium properties of warm dense matter, such as the dynamic structure factor (Baczewski et al., Phys. Rev. Lett., 116(11), 2016). While non-equilibrium properties, such as stopping power, have also been demonstrated to be within the grasp of TDDFT, the ultrafast isochoric heating of condensed matter into the warm dense state, enabled by recent advances in XFELs, remains beyond its capabilities. In this talk, we will describe the successes of and continuing challenges for TDDFT for warm dense matter, and present progress towards a more complete ab initio treatment of isochoric x-ray heating. Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International, Inc., for the DOE's National Nuclear Security Administration under contract DE-NA0003525.

  15. Generation of warm dense matter using an argon based capillary discharge laser

    NASA Astrophysics Data System (ADS)

    Rossall, A. K.; Tallents, G. J.

    2015-06-01

    Argon based capillary discharge lasers operating in the extreme ultra violet (EUV) at 46.9 nm with output up to 0.5 mJ energy per pulse and repetition rates up to 10 Hz are capable of focused irradiances of 109-1012 W cm-2 and can be used to generate plasma in the warm dense matter regime by irradiating solid material. To model the interaction between such an EUV laser and solid material, the 2D radiative-hydrodynamic code POLLUX has been modified to include absorption via direct photo-ionisation, a super-configuration model to describe the ionization-dependent electronic configurations and a calculation of plasma refractive indices for ray tracing of the incident EUV laser radiation. A simulation study is presented, demonstrating how capillary discharge lasers of 1200 ps pulse duration can be used to generate warm dense matter at close to solid densities with temperatures of a few eV and energy densities up to 1 × 105 J cm-3. Plasmas produced by EUV laser irradiation are shown to be useful for examining the properties of warm dense matter as, for example, plasma emission is not masked by hotter, less dense plasma emission that occurs with visible/infra-red laser target irradiation.

  16. Neutron Star Spin Measurements and Dense Matter with LOFT

    NASA Technical Reports Server (NTRS)

    Strohmayer, Tod

    2011-01-01

    Observations over the last decade with RXTE have begun to reveal the X-ray binary progenitors of the fastest spinning neutron stars presently known. Detection and study of the spin rates of binary neutron stars has important implications for constraining the nature of dense matter present in neutron star interiors, as both the maximum spin rate and mass for neutron stars is set by the equation of state. Precision pulse timing of accreting neutron star binaries can enable mass constraints. Particularly promIsing is the combination of the pulse and eclipse timing, as for example, in systems like Swift 11749.4-2807. With its greater sensitivity, LOFT will enable deeper searches for the spin periods of the neutron stars, both during persistent outburst intervals and thermonuclear X-ray bursts, and enable more precise modeling of detected pulsations. I will explore the anticipated impact of LOFT on spin measurements and its potential for constraining dense matter in neutron stars

  17. Linear dependence of surface expansion speed on initial plasma temperature in warm dense matter

    DOE PAGES

    Bang, Woosuk; Albright, Brian James; Bradley, Paul Andrew; ...

    2016-07-12

    Recent progress in laser-driven quasi-monoenergetic ion beams enabled the production of uniformly heated warm dense matter. Matter heated rapidly with this technique is under extreme temperatures and pressures, and promptly expands outward. While the expansion speed of an ideal plasma is known to have a square-root dependence on temperature, computer simulations presented here show a linear dependence of expansion speed on initial plasma temperature in the warm dense matter regime. The expansion of uniformly heated 1–100 eV solid density gold foils was modeled with the RAGE radiation-hydrodynamics code, and the average surface expansion speed was found to increase linearly withmore » temperature. The origin of this linear dependence is explained by comparing predictions from the SESAME equation-of-state tables with those from the ideal gas equation-of-state. In conclusion, these simulations offer useful insight into the expansion of warm dense matter and motivate the application of optical shadowgraphy for temperature measurement.« less

  18. Ultrafast visualization of the structural evolution of dense hydrogen towards warm dense matter

    NASA Astrophysics Data System (ADS)

    Fletcher, Luke

    2016-10-01

    Hot dense hydrogen far from equilibrium is ubiquitous in nature occurring during some of the most violent and least understood events in our universe such as during star formation, supernova explosions, and the creation of cosmic rays. It is also a state of matter important for applications in inertial confinement fusion research and in laser particle acceleration. Rapid progress occurred in recent years characterizing the high-pressure structural properties of dense hydrogen under static or dynamic compression. Here, we show that spectrally and angularly resolved x-ray scattering measure the thermodynamic properties of dense hydrogen and resolve the ultrafast evolution and relaxation towards thermodynamic equilibrium. These studies apply ultra-bright x-ray pulses from the Linac Coherent Light (LCLS) source. The interaction of rapidly heated cryogenic hydrogen with a high-peak power optical laser is visualized with intense LCLS x-ray pulses in a high-repetition rate pump-probe setting. We demonstrate that electron-ion coupling is affected by the small number of particles in the Debye screening cloud resulting in much slower ion temperature equilibration than predicted by standard theory. This work was supported by the DOE Office of Science, Fusion Energy Science under FWP 100182.

  19. Ab initio thermodynamic results for warm dense matter

    NASA Astrophysics Data System (ADS)

    Bonitz, Michael

    2016-10-01

    Warm dense matter (WDM) - an exotic state where electrons are quantum degenerate and ions may be strongly correlated - is ubiquitous in dense astrophysical plasmas and highly compressed laboratory systems including inertial fusion. Accurate theoretical predictions require precision thermodynamic data for the electron gas at high density and finite temperature around the Fermi temperature. First such data have been obtained by restricted path integral Monte Carlo (restricted PIMC) simulations and transformed into analytical fits for the free energy. Such results are also key input for novel finite temperature density functional theory. However, the RPIMC data of Ref. 1 are limited to moderate densities, and even there turned out to be surprisingly inaccurate, which is a consequence of the fermion sign problem. These problems were recently overcome by the development of alternative QMC approaches in Kiel (configuration PIMC and permutation blocking PIMC) and Imperial College (Density matrix QMC). The three methods have their strengths and limitations in complementary parameter regions and provide highly accurate thermodynamic data for the electronic contributions in WDM. While the original results were obtained for small particle numbers, recently accurate finite size corrections were derived allowing to compute ab initio thermodynamic data with an unprecedented accuracy of better than 0.3 percent. This provides the final step for the use as benchmark data for experiments and models of Warm dense matter. Co-authors: T. Schoof, S. Groth, T. Dornheim, F. D. Malone, M. Foulkes, and T. Sjostroem, Funded by: DFG via SFB-TR24 and project BO1366-10.

  20. The uniform electron gas at warm dense matter conditions

    NASA Astrophysics Data System (ADS)

    Dornheim, Tobias; Groth, Simon; Bonitz, Michael

    2018-05-01

    Motivated by the current high interest in the field of warm dense matter research, in this article we review the uniform electron gas (UEG) at finite temperature and over a broad density range relevant for warm dense matter applications. We provide an exhaustive overview of different simulation techniques, focusing on recent developments in the dielectric formalism (linear response theory) and quantum Monte Carlo (QMC) methods. Our primary focus is on two novel QMC methods that have recently allowed us to achieve breakthroughs in the thermodynamics of the warm dense electron gas: Permutation blocking path integral MC (PB-PIMC) and configuration path integral MC (CPIMC). In fact, a combination of PB-PIMC and CPIMC has allowed for a highly accurate description of the warm dense UEG over a broad density-temperature range. We are able to effectively avoid the notorious fermion sign problem, without invoking uncontrolled approximations such as the fixed node approximation. Furthermore, a new finite-size correction scheme is presented that makes it possible to treat the UEG in the thermodynamic limit without loss of accuracy. In addition, we in detail discuss the construction of a parametrization of the exchange-correlation free energy, on the basis of these data - the central thermodynamic quantity that provides a complete description of the UEG and is of crucial importance as input for the simulation of real warm dense matter applications, e.g., via thermal density functional theory. A second major aspect of this review is the use of our ab initio simulation results to test previous theories, including restricted PIMC, finite-temperature Green functions, the classical mapping by Perrot and Dharma-wardana, and various dielectric methods such as the random phase approximation, or the Singwi-Tosi-Land-Sjölander (both in the static and quantum versions), Vashishta-Singwi and the recent Tanaka scheme for the local field correction. Thus, for the first time, thorough

  1. Anomalous effects of dense matter under rotation

    NASA Astrophysics Data System (ADS)

    Huang, Xu-Guang; Nishimura, Kentaro; Yamamoto, Naoki

    2018-02-01

    We study the anomaly induced effects of dense baryonic matter under rotation. We derive the anomalous terms that account for the chiral vortical effect in the low-energy effective theory for light Nambu-Goldstone modes. The anomalous terms lead to new physical consequences, such as the anomalous Hall energy current and spontaneous generation of angular momentum in a magnetic field (or spontaneous magnetization by rotation). In particular, we show that, due to the presence of such anomalous terms, the ground state of the quantum chromodynamics (QCD) under sufficiently fast rotation becomes the "chiral soliton lattice" of neutral pions that has lower energy than the QCD vacuum and nuclear matter. We briefly discuss the possible realization of the chiral soliton lattice induced by a fast rotation in noncentral heavy ion collisions.

  2. Fluorescence and absorption spectroscopy for warm dense matter studies and ICF plasma diagnostics

    NASA Astrophysics Data System (ADS)

    Hansen, S. B.; Harding, E. C.; Knapp, P. F.; Gomez, M. R.; Nagayama, T.; Bailey, J. E.

    2018-05-01

    The burning core of an inertial confinement fusion (ICF) plasma produces bright x-rays at stagnation that can directly diagnose core conditions essential for comparison to simulations and understanding fusion yields. These x-rays also backlight the surrounding shell of warm, dense matter, whose properties are critical to understanding the efficacy of the inertial confinement and global morphology. We show that the absorption and fluorescence spectra of mid-Z impurities or dopants in the warm dense shell can reveal the optical depth, temperature, and density of the shell and help constrain models of warm, dense matter. This is illustrated by the example of a high-resolution spectrum collected from an ICF plasma with a beryllium shell containing native iron impurities. Analysis of the iron K-edge provides model-independent diagnostics of the shell density (2.3 × 1024 e/cm3) and temperature (10 eV), while a 12-eV red shift in Kβ and 5-eV blue shift in the K-edge discriminate among models of warm dense matter: Both shifts are well described by a self-consistent field model based on density functional theory but are not fully consistent with isolated-atom models using ad-hoc density effects.

  3. Fluorescence and absorption spectroscopy for warm dense matter studies and ICF plasma diagnostics

    DOE PAGES

    Hansen, Stephanie B.; Harding, Eric C.; Knapp, Patrick F.; ...

    2018-03-07

    The burning core of an inertial confinement fusion (ICF) plasma produces bright x-rays at stagnation that can directly diagnose core conditions essential for comparison to simulations and understanding fusion yields. These x-rays also backlight the surrounding shell of warm, dense matter, whose properties are critical to understanding the efficacy of the inertial confinement and global morphology. In this work, we show that the absorption and fluorescence spectra of mid-Z impurities or dopants in the warm dense shell can reveal the optical depth, temperature, and density of the shell and help constrain models of warm, dense matter. This is illustrated bymore » the example of a high-resolution spectrum collected from an ICF plasma with a beryllium shell containing native iron impurities. Lastly, analysis of the iron K-edge provides model-independent diagnostics of the shell density (2.3 × 10 24 e/cm 3) and temperature (10 eV), while a 12-eV red shift in Kβ and 5-eV blue shift in the K-edge discriminate among models of warm dense matter: Both shifts are well described by a self-consistent field model based on density functional theory but are not fully consistent with isolated-atom models using ad-hoc density effects.« less

  4. Energy transfer dynamics in strongly inhomogeneous hot-dense-matter systems

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Stillman, C. R.; Nilson, P. M.; Sefkow, A. B.

    Direct measurements of energy transfer across steep density and temperature gradients in a hot-dense-matter system are presented. Hot dense plasma conditions were generated by high-intensity laser irradiation of a thin-foil target containing a buried metal layer. Energy transfer to the layer was measured using picosecond time-resolved x-ray emission spectroscopy. Here, the data show two x-ray flashes in time. Fully explicit, coupled particle-in-cell and collisional-radiative atomic kinetics model predictions reproduce these observations, connecting the two x-ray flashes with staged radial energy transfer within the target.

  5. Energy transfer dynamics in strongly inhomogeneous hot-dense-matter systems

    DOE PAGES

    Stillman, C. R.; Nilson, P. M.; Sefkow, A. B.; ...

    2018-06-25

    Direct measurements of energy transfer across steep density and temperature gradients in a hot-dense-matter system are presented. Hot dense plasma conditions were generated by high-intensity laser irradiation of a thin-foil target containing a buried metal layer. Energy transfer to the layer was measured using picosecond time-resolved x-ray emission spectroscopy. Here, the data show two x-ray flashes in time. Fully explicit, coupled particle-in-cell and collisional-radiative atomic kinetics model predictions reproduce these observations, connecting the two x-ray flashes with staged radial energy transfer within the target.

  6. Neutrino Oscillations in Dense Matter

    NASA Astrophysics Data System (ADS)

    Lobanov, A. E.

    2017-03-01

    A modification of the electroweak theory, where the fermions with the same electroweak quantum numbers are combined in multiplets and are treated as different quantum states of a single particle, is proposed. In this model, mixing and oscillations of particles arise as a direct consequence of the general principles of quantum field theory. The developed approach enables one to calculate the probabilities of the processes taking place in the detector at long distances from the particle source. Calculations of higher-order processes, including computation of the contributions due to radiative corrections, can be performed in the framework of the perturbation theory using the regular diagram technique. As a result, the analog to the Dirac-Schwinger equation of quantum electrodynamics describing neutrino oscillations and its spin rotation in dense matter can be obtained.

  7. Kinetic theory molecular dynamics and hot dense matter: theoretical foundations.

    PubMed

    Graziani, F R; Bauer, J D; Murillo, M S

    2014-09-01

    Electrons are weakly coupled in hot, dense matter that is created in high-energy-density experiments. They are also mildly quantum mechanical and the ions associated with them are classical and may be strongly coupled. In addition, the dynamical evolution of plasmas under these hot, dense matter conditions involve a variety of transport and energy exchange processes. Quantum kinetic theory is an ideal tool for treating the electrons but it is not adequate for treating the ions. Molecular dynamics is perfectly suited to describe the classical, strongly coupled ions but not the electrons. We develop a method that combines a Wigner kinetic treatment of the electrons with classical molecular dynamics for the ions. We refer to this hybrid method as "kinetic theory molecular dynamics," or KTMD. The purpose of this paper is to derive KTMD from first principles and place it on a firm theoretical foundation. The framework that KTMD provides for simulating plasmas in the hot, dense regime is particularly useful since current computational methods are generally limited by their inability to treat the dynamical quantum evolution of the electronic component. Using the N-body von Neumann equation for the electron-proton plasma, three variations of KTMD are obtained. Each variant is determined by the physical state of the plasma (e.g., collisional versus collisionless). The first variant of KTMD yields a closed set of equations consisting of a mean-field quantum kinetic equation for the electron one-particle distribution function coupled to a classical Liouville equation for the protons. The latter equation includes both proton-proton Coulombic interactions and an effective electron-proton interaction that involves the convolution of the electron density with the electron-proton Coulomb potential. The mean-field approach is then extended to incorporate equilibrium electron-proton correlations through the Singwi-Tosi-Land-Sjolander (STLS) ansatz. This is the second variant of KTMD

  8. Symmetry energy in cold dense matter

    NASA Astrophysics Data System (ADS)

    Jeong, Kie Sang; Lee, Su Houng

    2016-01-01

    We calculate the symmetry energy in cold dense matter both in the normal quark phase and in the 2-color superconductor (2SC) phase. For the normal phase, the thermodynamic potential is calculated by using hard dense loop (HDL) resummation to leading order, where the dominant contribution comes from the longitudinal gluon rest mass. The effect of gluonic interaction on the symmetry energy, obtained from the thermodynamic potential, was found to be small. In the 2SC phase, the non-perturbative BCS paring gives enhanced symmetry energy as the gapped states are forced to be in the common Fermi sea reducing the number of available quarks that can contribute to the asymmetry. We used high density effective field theory to estimate the contribution of gluon interaction to the symmetry energy. Among the gluon rest masses in 2SC phase, only the Meissner mass has iso-spin dependence although the magnitude is much smaller than the Debye mass. As the iso-spin dependence of gluon rest masses is even smaller than the case in the normal phase, we expect that the contribution of gluonic interaction to the symmetry energy in the 2SC phase will be minimal. The different value of symmetry energy in each phase will lead to different prediction for the particle yields in heavy ion collision experiment.

  9. Measurement of Preheat Due to Nonlocal Electron Transport in Warm Dense Matter

    NASA Astrophysics Data System (ADS)

    Falk, K.; Holec, M.; Fontes, C. J.; Fryer, C. L.; Greeff, C. W.; Johns, H. M.; Montgomery, D. S.; Schmidt, D. W.; Šmíd, M.

    2018-01-01

    This Letter presents a novel approach to study electron transport in warm dense matter. It also includes the first x-ray Thomson scattering (XRTS) measurement from low-density CH foams compressed by a strong laser-driven shock at the OMEGA laser facility. The XRTS measurement is combined with velocity interferometry (VISAR) and optical pyrometry (SOP) providing a robust measurement of thermodynamic conditions in the shock. Evidence of significant preheat contributing to elevated temperatures reaching 17.5-35 eV in shocked CH foam is measured by XRTS. These measurements are complemented by abnormally high shock velocities observed by VISAR and early emission seen by SOP. These results are compared to radiation hydrodynamics simulations that include first-principles treatment of nonlocal electron transport in warm dense matter with excellent agreement. Additional simulations confirm that the x-ray contribution to this preheat is negligible.

  10. Single-shot mega-electronvolt ultrafast electron diffraction for structure dynamic studies of warm dense matter

    NASA Astrophysics Data System (ADS)

    Mo, M. Z.; Shen, X.; Chen, Z.; Li, R. K.; Dunning, M.; Sokolowski-Tinten, K.; Zheng, Q.; Weathersby, S. P.; Reid, A. H.; Coffee, R.; Makasyuk, I.; Edstrom, S.; McCormick, D.; Jobe, K.; Hast, C.; Glenzer, S. H.; Wang, X.

    2016-11-01

    We have developed a single-shot mega-electronvolt ultrafast-electron-diffraction system to measure the structural dynamics of warm dense matter. The electron probe in this system is featured by a kinetic energy of 3.2 MeV and a total charge of 20 fC, with the FWHM pulse duration and spot size at sample of 350 fs and 120 μm respectively. We demonstrate its unique capability by visualizing the atomic structural changes of warm dense gold formed from a laser-excited 35-nm freestanding single-crystal gold foil. The temporal evolution of the Bragg peak intensity and of the liquid signal during solid-liquid phase transition are quantitatively determined. This experimental capability opens up an exciting opportunity to unravel the atomic dynamics of structural phase transitions in warm dense matter regime.

  11. Measurement of Preheat Due to Nonlocal Electron Transport in Warm Dense Matter

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Falk, K.; Holec, M.; Fontes, C. J.

    This work presents a novel approach to study electron transport in warm dense matter. It also includes the first x-ray Thomson scattering (XRTS) measurement from low-density CH foams compressed by a strong laser-driven shock at the OMEGA laser facility. The XRTS measurement is combined with velocity interferometry (VISAR) and optical pyrometry (SOP) providing a robust measurement of thermodynamic conditions in the shock. Evidence of significant preheat contributing to elevated temperatures reaching 17.5–35 eV in shocked CH foam is measured by XRTS. These measurements are complemented by abnormally high shock velocities observed by VISAR and early emission seen by SOP. Thesemore » results are compared to radiation hydrodynamics simulations that include first-principles treatment of nonlocal electron transport in warm dense matter with excellent agreement. Additional simulations confirm that the x-ray contribution to this preheat is negligible.« less

  12. Measurement of Preheat Due to Nonlocal Electron Transport in Warm Dense Matter

    DOE PAGES

    Falk, K.; Holec, M.; Fontes, C. J.; ...

    2018-01-10

    This work presents a novel approach to study electron transport in warm dense matter. It also includes the first x-ray Thomson scattering (XRTS) measurement from low-density CH foams compressed by a strong laser-driven shock at the OMEGA laser facility. The XRTS measurement is combined with velocity interferometry (VISAR) and optical pyrometry (SOP) providing a robust measurement of thermodynamic conditions in the shock. Evidence of significant preheat contributing to elevated temperatures reaching 17.5–35 eV in shocked CH foam is measured by XRTS. These measurements are complemented by abnormally high shock velocities observed by VISAR and early emission seen by SOP. Thesemore » results are compared to radiation hydrodynamics simulations that include first-principles treatment of nonlocal electron transport in warm dense matter with excellent agreement. Additional simulations confirm that the x-ray contribution to this preheat is negligible.« less

  13. Single-shot mega-electronvolt ultrafast electron diffraction for structure dynamic studies of warm dense matter

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Mo, M. Z., E-mail: mmo09@slac.stanford.edu; Shen, X.; Chen, Z.

    We have developed a single-shot mega-electronvolt ultrafast-electron-diffraction system to measure the structural dynamics of warm dense matter. The electron probe in this system is featured by a kinetic energy of 3.2 MeV and a total charge of 20 fC, with the FWHM pulse duration and spot size at sample of 350 fs and 120 μm respectively. We demonstrate its unique capability by visualizing the atomic structural changes of warm dense gold formed from a laser-excited 35-nm freestanding single-crystal gold foil. The temporal evolution of the Bragg peak intensity and of the liquid signal during solid-liquid phase transition are quantitatively determined.more » This experimental capability opens up an exciting opportunity to unravel the atomic dynamics of structural phase transitions in warm dense matter regime.« less

  14. Single-shot mega-electronvolt ultrafast electron diffraction for structure dynamic studies of warm dense matter

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Mo, M. Z.; Shen, X.; Chen, Z.

    We have developed a single-shot mega-electronvolt ultrafast-electron-diffraction system to measure the structural dynamics of warm dense matter. The electron probe in this system is featured by a kinetic energy of 3.2 MeV and a total charge of 20 fC, with the FWHM pulse duration and spot size at sample of 350 fs and 120 µm respectively. We demonstrate its unique capability by visualizing the atomic structural changes of warm dense gold formed from a laser-excited 35-nm freestanding single-crystal gold foil. The temporal evolution of the Bragg peak intensity and of the liquid signal during solid-liquid phase transition are quantitatively determined.more » This experimental capability opens up an exciting opportunity to unravel the atomic dynamics of structural phase transitions in warm dense matter regime« less

  15. Single-shot mega-electronvolt ultrafast electron diffraction for structure dynamic studies of warm dense matter

    DOE PAGES

    Mo, M. Z.; Shen, X.; Chen, Z.; ...

    2016-08-04

    We have developed a single-shot mega-electronvolt ultrafast-electron-diffraction system to measure the structural dynamics of warm dense matter. The electron probe in this system is featured by a kinetic energy of 3.2 MeV and a total charge of 20 fC, with the FWHM pulse duration and spot size at sample of 350 fs and 120 µm respectively. We demonstrate its unique capability by visualizing the atomic structural changes of warm dense gold formed from a laser-excited 35-nm freestanding single-crystal gold foil. The temporal evolution of the Bragg peak intensity and of the liquid signal during solid-liquid phase transition are quantitatively determined.more » This experimental capability opens up an exciting opportunity to unravel the atomic dynamics of structural phase transitions in warm dense matter regime« less

  16. Study of the Warm Dense Matter with XANES spectroscopy - Applications to planetary interiors

    NASA Astrophysics Data System (ADS)

    Denoeud, Adrien

    With the recent discovery of many exoplanets, modelling the interior of these celestial bodies is becoming a fascinating scientific challenge. In this context, it is crucial to accurately know the equations of state and the macroscopic and microscopic physical properties of their constituent materials in the Warm Dense Matter regime (WDM). Moreover, planetary models rely almost exclusively on physical properties obtained using first principles simulations based on density functional theory (DFT) predictions. It is thus of paramount importance to validate the basic underlying mechanisms occurring for key planetary constituents (metallization, dissociation, structural modifications, phase transitions, etc....) as pressure and temperature both increase. In this work, we were interested in two materials that can be mainly found in the Earth-like planets: silica, or SiO2, as a model compound of the silicates that constitute the major part of their mantles, and iron, which is found in abundance in their cores. These two materials were compressed and brought to the WDM regime by using strong shock created by laser pulses during various experiments performed on the LULI2000 (Palaiseau, France) and the JLF (Livermore, US) laser facilities and on the LCLS XFEL (Stanford, US). In order to penetrate this dense matter and to have access to its both ionic and electronic structures, we have probed silica and iron with time-resolved X-ray Absorption Near Edge Structure (XANES). In parallel with these experiments, we performed quantum molecular dynamics simulations based on DFT at conditions representative of the region investigated experimentally so as to extract the interesting physical processes and comprehend the limits of the implemented models. In particular, these works allowed us to highlight the metallization processes of silica in temperature and the structural changes of its liquid in density, as well as to more constrain the melting curve of iron at very high pressures.

  17. Confronting effective models for deconfinement in dense quark matter with lattice data

    NASA Astrophysics Data System (ADS)

    Andersen, Jens O.; Brauner, Tomáš; Naylor, William R.

    2015-12-01

    Ab initio numerical simulations of the thermodynamics of dense quark matter remain a challenge. Apart from the infamous sign problem, lattice methods have to deal with finite volume and discretization effects as well as with the necessity to introduce sources for symmetry-breaking order parameters. We study these artifacts in the Polyakov-loop-extended Nambu-Jona-Lasinio (PNJL) model and compare its predictions to existing lattice data for cold and dense two-color matter with two flavors of Wilson quarks. To achieve even qualitative agreement with lattice data requires the introduction of two novel elements in the model: (i) explicit chiral symmetry breaking in the effective contact four-fermion interaction, referred to as the chiral twist, and (ii) renormalization of the Polyakov loop. The feedback of the dense medium to the gauge sector is modeled by a chemical-potential-dependent scale in the Polyakov-loop potential. In contrast to previously used analytical Ansätze, we determine its dependence on the chemical potential from lattice data for the expectation value of the Polyakov loop. Finally, we propose adding a two-derivative operator to our effective model. This term acts as an additional source of explicit chiral symmetry breaking, mimicking an analogous term in the lattice Wilson action.

  18. Topical Collaboration "Neutrinos and Nucleosynthesis in Hot and Dense Matter"

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Allahverdi, Rouzbeh

    2015-09-18

    This is the final technical report describing contributions from the University of New Mexico to Topical Collaboration on "Neutrinos and Nucleosynthesis in Hot and Dense Matter" in the period June 2010 through May 2015. During the funding period, the University of New Mexico successfully hired Huaiyu Duan as a new faculty member with the support from DOE, who has contributed to the Topical Collaboration through his research and collaborations.

  19. Guiding of relativistic electron beams in dense matter by laser-driven magnetostatic fields.

    PubMed

    Bailly-Grandvaux, M; Santos, J J; Bellei, C; Forestier-Colleoni, P; Fujioka, S; Giuffrida, L; Honrubia, J J; Batani, D; Bouillaud, R; Chevrot, M; Cross, J E; Crowston, R; Dorard, S; Dubois, J-L; Ehret, M; Gregori, G; Hulin, S; Kojima, S; Loyez, E; Marquès, J-R; Morace, A; Nicolaï, Ph; Roth, M; Sakata, S; Schaumann, G; Serres, F; Servel, J; Tikhonchuk, V T; Woolsey, N; Zhang, Z

    2018-01-09

    Intense lasers interacting with dense targets accelerate relativistic electron beams, which transport part of the laser energy into the target depth. However, the overall laser-to-target energy coupling efficiency is impaired by the large divergence of the electron beam, intrinsic to the laser-plasma interaction. Here we demonstrate that an efficient guiding of MeV electrons with about 30 MA current in solid matter is obtained by imposing a laser-driven longitudinal magnetostatic field of 600 T. In the magnetized conditions the transported energy density and the peak background electron temperature at the 60-μm-thick target's rear surface rise by about a factor of five, as unfolded from benchmarked simulations. Such an improvement of energy-density flux through dense matter paves the ground for advances in laser-driven intense sources of energetic particles and radiation, driving matter to extreme temperatures, reaching states relevant for planetary or stellar science as yet inaccessible at the laboratory scale and achieving high-gain laser-driven thermonuclear fusion.

  20. New possibilities in supernova accretion phase from dense matter effect

    NASA Astrophysics Data System (ADS)

    Chakraborty, S.; Mirizzi, A.; Saviano, N.

    2012-07-01

    We carry out a detailed analysis of the supernova (SN) neutrino flavor evolution during the accretion phase (at post-bounce times tpb <= 500 ms), characterizing the SN ν signal by recent hydrodynamical simulations. We find that trajectory-dependent multi-angle effects, associated with the dense ordinary matter suppress collective oscillations, that would have been induced by ν-ν interactions in the deepest SN regions. The matter suppression implies that neutrino oscillations will start outside the neutrino decoupling region and therefore will have a negligible impact on the neutrino heating and the explosion dynamics. Furthermore, the possible detection of the next galactic SN neutrino signal from the accretion phase, based on the usual Mikheyev-Smirnov-Wolfenstein effect in the SN mantle and Earth matter effects, can reveal the neutrino mass hierarchy in the likely case that the mixing angle θ13 is not very small.

  1. Domain Walls and Strings in Dense Quark Matter

    NASA Astrophysics Data System (ADS)

    Zhitnitsky, Ariel R.

    2002-12-01

    I discuss several types of domain walls and global strings which occur in colour superconducting quark matter due to the spontaneous violation of relevant U(1) and discrete symmetries. These include the baryon U(1)B, approximate axial U(1)A symmetries as well as an approximate U(1)Y symmetry arising from kaon condensation in colour-flavour locking phase. In this talk I concentrate on discussions of K strings due to their interesting internal structures. Specifically, I demonstrate that under some conditions the global U(1)Y symmetry may not be restored inside the string, in contrast with the standard expectations. Instead, K+ condensation occurs inside the core of the string if a relevant parameter \\cos θ K0 ≡ mK0^2 /μ eff2 is larger than some critical value θK0 ≥ θcrit. If this phenomenon happens, the U(1)Y strings become superconducting and may considerably influence the magnetic properties of dense quark matter, in particular in neutron stars.

  2. A single-shot spatial chirp method for measuring initial AC conductivity evolution of femtosecond laser pulse excited warm dense matter

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Chen, Z.; Hering, P.; Brown, S. B.

    To study the rapid evolution of AC conductivity from ultrafast laser excited warm dense matter (WDM), a spatial chirp single-shot method is developed utilizing a crossing angle pump-probe configuration. The pump beam is shaped individually in two spatial dimensions so that it can provide both sufficient laser intensity to excite the material to warm dense matter state and a uniform time window of up to 1 ps with sub-100 fs FWHM temporal resolution. Here, temporal evolution of AC conductivity in laser excited warm dense gold was also measured.

  3. A single-shot spatial chirp method for measuring initial AC conductivity evolution of femtosecond laser pulse excited warm dense matter

    DOE PAGES

    Chen, Z.; Hering, P.; Brown, S. B.; ...

    2016-09-19

    To study the rapid evolution of AC conductivity from ultrafast laser excited warm dense matter (WDM), a spatial chirp single-shot method is developed utilizing a crossing angle pump-probe configuration. The pump beam is shaped individually in two spatial dimensions so that it can provide both sufficient laser intensity to excite the material to warm dense matter state and a uniform time window of up to 1 ps with sub-100 fs FWHM temporal resolution. Here, temporal evolution of AC conductivity in laser excited warm dense gold was also measured.

  4. Dissipationless Hall current in dense quark matter in a magnetic field

    DOE PAGES

    Ferrer, Efrain J.; de la Incera, V.

    2017-03-29

    Here, we show the realization of axion electrodynamics within the Dual Chiral Density Wave phase of dense quark matter in the presence of a magnetic field. This system exhibits an anomalous dissipationless Hall current perpendicular to the magnetic field and an anomalous electric charge density. This connection to topological insulators and 3D optical lattices, as well as possible implications for heavy-ion collisions and neutron stars are outlined.

  5. Path Integral Monte Carlo Simulations of Warm Dense Matter and Plasmas

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Militzer, Burkhard

    2018-01-13

    New path integral Monte Carlo simulation (PIMC) techniques will be developed and applied to derive the equation of state (EOS) for the regime of warm dense matter and dense plasmas where existing first-principles methods cannot be applied. While standard density functional theory has been used to accurately predict the structure of many solids and liquids up to temperatures on the order of 10,000 K, this method is not applicable at much higher temperature where electronic excitations become important because the number of partially occupied electronic orbitals reaches intractably large numbers and, more importantly, the use of zero-temperature exchange-correlation functionals introducesmore » an uncontrolled approximation. Here we focus on PIMC methods that become more and more efficient with increasing temperatures and still include all electronic correlation effects. In this approach, electronic excitations increase the efficiency rather than reduce it. While it has commonly been assumed such methods can only be applied to elements without core electrons like hydrogen and helium, we recently showed how to extend PIMC to heavier elements by performing the first PIMC simulations of carbon and water plasmas [Driver, Militzer, Phys. Rev. Lett. 108 (2012) 115502]. Here we propose to continue this important development to extend the reach of PIMC simulations to yet heavier elements and also lower temperatures. The goal is to provide a robust first-principles simulation method that can accurately and efficiently study materials with excited electrons at solid-state densities in order to access parts of the phase diagram such the regime of warm dense matter and plasmas where so far only more approximate, semi-analytical methods could be applied.« less

  6. Quantum molecular dynamics simulations of dense matter

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Collins, L.; Kress, J.; Troullier, N.

    1997-12-31

    The authors have developed a quantum molecular dynamics (QMD) simulation method for investigating the properties of dense matter in a variety of environments. The technique treats a periodically-replicated reference cell containing N atoms in which the nuclei move according to the classical equations-of-motion. The interatomic forces are generated from the quantum mechanical interactions of the (between?) electrons and nuclei. To generate these forces, the authors employ several methods of varying sophistication from the tight-binding (TB) to elaborate density functional (DF) schemes. In the latter case, lengthy simulations on the order of 200 atoms are routinely performed, while for the TB,more » which requires no self-consistency, upwards to 1000 atoms are systematically treated. The QMD method has been applied to a variety cases: (1) fluid/plasma Hydrogen from liquid density to 20 times volume-compressed for temperatures of a thousand to a million degrees Kelvin; (2) isotopic hydrogenic mixtures, (3) liquid metals (Li, Na, K); (4) impurities such as Argon in dense hydrogen plasmas; and (5) metal/insulator transitions in rare gas systems (Ar,Kr) under high compressions. The advent of parallel versions of the methods, especially for fast eigensolvers, presage LDA simulations in the range of 500--1000 atoms and TB runs for tens of thousands of particles. This leap should allow treatment of shock chemistry as well as large-scale mixtures of species in highly transient environments.« less

  7. Probing properties of hot and dense QCD matter with heavy flavor in the PHENIX experiment at RHIC

    DOE PAGES

    Nouicer, Rachid

    2015-05-29

    Hadrons carrying heavy quarks, i.e. charm or bottom, are important probes of the hot and dense medium created in relativistic heavy ion collisions. Heavy quark-antiquark pairs are mainly produced in initial hard scattering processes of partons. While some of the produced pairs form bound quarkonia, the vast majority hadronize into particles carrying open heavy flavor. Heavy quark production has been studied by the PHENIX experiment at RHIC via measurements of single leptons from semi-leptonic decays in both the electron channel at mid-rapidity and in the muon channel at forward rapidity. A large suppression and azimuthal anisotropy of single electrons havemore » been observed in Au + Au collisions at 200 GeV. These results suggest a large energy loss and flow of heavy quarks in the hot, dense matter. The PHENIX experiment has also measured J/ψ production at 200 GeV in p + p, d + Au, Cu + Cu and Au + Au collisions, both at mid- and forward-rapidities, and additionally Cu + Au and U + U at forward-rapidities. In the most energetic collisions, more suppression is observed at forward rapidity than at central rapidity. This can be interpreted either as a sign of quark recombination, or as a hint of additional cold nuclear matter effects. The centrality dependence of nuclear modification factor, R AA(p T), for J/ψ in U + U collisions at √ sNN = 193 GeV shows a similar trend to the lighter systems, Au + Au and Cu + Cu, at similar energy 200 GeV.« less

  8. Warm Dense Matter Demonstrating Non-Drude Conductivity from Observations of Nonlinear Plasmon Damping

    NASA Astrophysics Data System (ADS)

    Witte, B. B. L.; Fletcher, L. B.; Galtier, E.; Gamboa, E.; Lee, H. J.; Zastrau, U.; Redmer, R.; Glenzer, S. H.; Sperling, P.

    2017-06-01

    We present simulations using finite-temperature density-functional-theory molecular dynamics to calculate the dynamic electrical conductivity in warm dense aluminum. The comparison between exchange-correlation functionals in the Perdew-Burke-Enzerhof and Heyd-Scuseria-Enzerhof (HSE) approximation indicates evident differences in the density of states and the dc conductivity. The HSE calculations show excellent agreement with experimental Linac Coherent Light Source x-ray plasmon scattering spectra revealing plasmon damping below the widely used random phase approximation. These findings demonstrate non-Drude-like behavior of the dynamic conductivity that needs to be taken into account to determine the optical properties of warm dense matter.

  9. Experiment Provides the Best Look Yet at 'Warm Dense Matter' at Cores of Giant Planets

    ScienceCinema

    None

    2018-05-24

    In an experiment at the Department of Energy's SLAC National Accelerator Laboratory, scientists precisely measured the temperature and structure of aluminum as it transitions into a superhot, highly compressed concoction known as “warm dense matter.”

  10. Modeling Transport of Relativistic Electrons through Warm-Dense Matter Using Collisional PIC

    NASA Astrophysics Data System (ADS)

    May, J.; McGuffey, C.; Yabuuchi, T.; Wei, Ms; Beg, F.; Mori, Wb

    2017-10-01

    In electron transport experiments performed on the OMEGA EP laser system, a relativistic electron beam was created by focusing a high intensity (eA /me c > 1) laser onto a gold (Au) foil. Behind the Au foil was a layer of plastic (CH) foam, with an initial density of 200mg /cm3 . Before the high intensity laser was switched on, this foam was either left unperturbed; or it was shocked using a lower intensity laser (eA /me c 10-4) with beam path perpendicular to the high intensity laser, which left the CH layer in a warm dense matter (WDM) state with temperature of 40 eV and density of 30mg /cm3 . The electron beam was imaged by observing the k- α signal from a copper foil on the far side from the Au. The result was that transport was decreased by an order of magnitude in the WDM compared to the cold foam. We have modeled this experiment using the PIC code OSIRIS, with also a Monte Carlo Coulomb collision package. Our simulations indicate that the main cause of the differences in transport is a collimating magnetic field in the higher density, cold foam, created by collisional resistivity. The plasma density of the Au layer, difficult to model fully in PIC, appears to effect the heat capacity and therefore temperature and resistivity of the target. The authors acknowledge the support of the Department of Energy under contract DE-NA 0001833 and the National Science Foundation under contract ACI 1339893.

  11. Theoretical model of x-ray scattering as a dense matter probe.

    PubMed

    Gregori, G; Glenzer, S H; Rozmus, W; Lee, R W; Landen, O L

    2003-02-01

    We present analytical expressions for the dynamic structure factor, or form factor S(k,omega), which is the quantity describing the x-ray cross section from a dense plasma or a simple liquid. Our results, based on the random phase approximation for the treatment on the charged particle coupling, can be applied to describe scattering from either weakly coupled classical plasmas or degenerate electron liquids. Our form factor correctly reproduces the Compton energy down-shift and the known Fermi-Dirac electron velocity distribution for S(k,omega) in the case of a cold degenerate plasma. The usual concept of scattering parameter is also reinterpreted for the degenerate case in order to include the effect of the Thomas-Fermi screening. The results shown in this work can be applied to interpreting x-ray scattering in warm dense plasmas occurring in inertial confinement fusion experiments or for the modeling of solid density matter found in the interior of planets.

  12. Generation and characterisation of warm dense matter with intense lasers

    NASA Astrophysics Data System (ADS)

    Riley, D.

    2018-01-01

    In this paper I discuss the subject of warm dense matter (WDM), which, apart from being of academic interest and relevant to inertial fusion capsules, is a subject of importance to those who wish to understand the formation and structure of planetary interiors and other astrophysical bodies. I broadly outline some key properties of WDM and go on to discuss various methods of generating samples in the laboratory using large laser facilities and outline some common techniques of diagnosis. It is not intended as a comprehensive review but rather a brief outline for scientists new to the field and those with an interest but not working in the field directly.

  13. Degenerate limit thermodynamics beyond leading order for models of dense matter

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Constantinou, Constantinos, E-mail: c.constantinou@fz-juelich.de; Muccioli, Brian, E-mail: bm956810@ohio.edu; Prakash, Madappa, E-mail: prakash@ohio.edu

    2015-12-15

    Analytical formulas for next-to-leading order temperature corrections to the thermal state variables of interacting nucleons in bulk matter are derived in the degenerate limit. The formalism developed is applicable to a wide class of non-relativistic and relativistic models of hot and dense matter currently used in nuclear physics and astrophysics (supernovae, proto-neutron stars and neutron star mergers) as well as in condensed matter physics. We consider the general case of arbitrary dimensionality of momentum space and an arbitrary degree of relativity (for relativistic models). For non-relativistic zero-range interactions, knowledge of the Landau effective mass suffices to compute next-to-leading order effects,more » but for finite-range interactions, momentum derivatives of the Landau effective mass function up to second order are required. Results from our analytical formulas are compared with the exact results for zero- and finite-range potential and relativistic mean-field theoretical models. In all cases, inclusion of next-to-leading order temperature effects substantially extends the ranges of partial degeneracy for which the analytical treatment remains valid. Effects of many-body correlations that deserve further investigation are highlighted.« less

  14. Bypassing the malfunction junction in warm dense matter simulations

    NASA Astrophysics Data System (ADS)

    Cangi, Attila; Pribram-Jones, Aurora

    2015-03-01

    Simulation of warm dense matter requires computational methods that capture both quantum and classical behavior efficiently under high-temperature and high-density conditions. The state-of-the-art approach to model electrons and ions under those conditions is density functional theory molecular dynamics, but this method's computational cost skyrockets as temperatures and densities increase. We propose finite-temperature potential functional theory as an in-principle-exact alternative that suffers no such drawback. In analogy to the zero-temperature theory developed previously, we derive an orbital-free free energy approximation through a coupling-constant formalism. Our density approximation and its associated free energy approximation demonstrate the method's accuracy and efficiency. A.C. has been partially supported by NSF Grant CHE-1112442. A.P.J. is supported by DOE Grant DE-FG02-97ER25308.

  15. Dynamic electron-ion collisions and nuclear quantum effects in quantum simulation of warm dense matter.

    PubMed

    Kang, Dongdong; Dai, Jiayu

    2018-02-21

    The structural, thermodynamic and transport properties of warm dense matter (WDM) are crucial to the fields of astrophysics and planet science, as well as inertial confinement fusion. WDM refers to the states of matter in a regime of temperature and density between cold condensed matter and hot ideal plasmas, where the density is from near-solid up to ten times solid density, and the temperature between 0.1 and 100 eV. In the WDM regime, matter exhibits moderately or strongly coupled, partially degenerate properties. Therefore, the methods used to deal with condensed matter and isolated atoms need to be properly validated for WDM. It is therefore a big challenge to understand WDM within a unified theoretical description with reliable accuracy. Here, we review the progress in the theoretical study of WDM with state-of-the-art simulations, i.e. quantum Langevin molecular dynamics and first principles path integral molecular dynamics. The related applications for WDM are also included.

  16. Dynamic electron-ion collisions and nuclear quantum effects in quantum simulation of warm dense matter

    NASA Astrophysics Data System (ADS)

    Kang, Dongdong; Dai, Jiayu

    2018-02-01

    The structural, thermodynamic and transport properties of warm dense matter (WDM) are crucial to the fields of astrophysics and planet science, as well as inertial confinement fusion. WDM refers to the states of matter in a regime of temperature and density between cold condensed matter and hot ideal plasmas, where the density is from near-solid up to ten times solid density, and the temperature between 0.1 and 100 eV. In the WDM regime, matter exhibits moderately or strongly coupled, partially degenerate properties. Therefore, the methods used to deal with condensed matter and isolated atoms need to be properly validated for WDM. It is therefore a big challenge to understand WDM within a unified theoretical description with reliable accuracy. Here, we review the progress in the theoretical study of WDM with state-of-the-art simulations, i.e. quantum Langevin molecular dynamics and first principles path integral molecular dynamics. The related applications for WDM are also included.

  17. Inelastic X-ray Scattering Measurements of Ionization in Warm, Dense Matter

    NASA Astrophysics Data System (ADS)

    Davis, Paul F.

    In this work we demonstrate spectrally resolved x-ray scattering from electron-plasma waves in shock-compressed deuterium and proton-heated matter. Because the spectral signature of inelastic x-ray scattering is strongly dependent on the free electron density of the system, it is used to infer ionization in dynamically heated samples. Using 2-6 ns, 500 J laser pulses from LLNL's Janus laser, we shocked liquid deuterium to pressures approaching 50 GPa, reaching compressions of 4 times liquid density. A second laser produced intense 2 keV x-rays. By collecting and spectrally dispersing forward scattered photons at 45°, the onset of ionization was detected at compressions of about 3 times in the form of plasmon oscillations. Backscattered x-rays bolstered this observation by measuring the free electron distribution through Compton scattering. Comparison with simulations shows very close agreement between the pressure dependence of ionization and molecular dissociation in dynamically compressed deuterium. In a second set of experiments, a 10 ps, 200 J Titan laser pulse was split into two beams. One created a stream of MeV protons to heat samples of boron and boron-nitride and the other pumped 4.5 keV K-alpha radiation in a titanium foil to probe the hot target. We observed scattered x-rays 300 ps after heating, noting a strong difference in average ionization between the two target materials at temperatures of 16 eV and very similar mass densities. Comparison with electron structure calculations suggests that this difference is due to a persistence of long-range ion structure in BN resulting in high-temperature band structure. These results underscore the importance of understanding the complex electron structure of materials even at electron-volt temperatures and gigapascal pressures. Our results provide new data to guide the theoretical modeling of warm, dense matter important to understanding giant planets and inertial fusion targets.

  18. X-ray Thomson Scattering in Warm Dense Matter without the Chihara Decomposition.

    PubMed

    Baczewski, A D; Shulenburger, L; Desjarlais, M P; Hansen, S B; Magyar, R J

    2016-03-18

    X-ray Thomson scattering is an important experimental technique used to measure the temperature, ionization state, structure, and density of warm dense matter (WDM). The fundamental property probed in these experiments is the electronic dynamic structure factor. In most models, this is decomposed into three terms [J. Chihara, J. Phys. F 17, 295 (1987)] representing the response of tightly bound, loosely bound, and free electrons. Accompanying this decomposition is the classification of electrons as either bound or free, which is useful for gapped and cold systems but becomes increasingly questionable as temperatures and pressures increase into the WDM regime. In this work we provide unambiguous first principles calculations of the dynamic structure factor of warm dense beryllium, independent of the Chihara form, by treating bound and free states under a single formalism. The computational approach is real-time finite-temperature time-dependent density functional theory (TDDFT) being applied here for the first time to WDM. We compare results from TDDFT to Chihara-based calculations for experimentally relevant conditions in shock-compressed beryllium.

  19. Experimental station for ultrafast extreme ultraviolet spectroscopy for non-equilibrium dynamics in warm dense matter

    NASA Astrophysics Data System (ADS)

    Lee, Jong-won; Geng, Xiaotao; Jung, Jae Hyung; Cho, Min Sang; Yang, Seong Hyeok; Jo, Jawon; Lee, Chang-lyoul; Cho, Byoung Ick; Kim, Dong-Eon

    2018-07-01

    Recent interest in highly excited matter generated by intense femtosecond laser pulses has led to experimental methods that directly investigate ultrafast non-equilibrium electronic and structural dynamics. We present a tabletop experimental station for the extreme ultraviolet (EUV) spectroscopy used to trace L-edge dynamics in warm dense aluminum with a temporal resolution of a hundred femtoseconds. The system consists of the EUV probe generation part via a high-order harmonic generation process of femtosecond laser pulses with atomic clusters, a beamline with high-throughput optics and a sample-refreshment system of nano-foils utilizing the full repetition rate of the probe, and a flat-field EUV spectrograph. With the accumulation of an order of a hundred shots, a clear observation of the change in the aluminum L-shell absorption was achieved with a temporal resolution of 90 fs in a 600-fs window. The signature of a non-equilibrium electron distribution over a 10-eV range and its evolution to a 1-eV Fermi distribution are observed. This demonstrates the capability of this apparatus to capture the non-equilibrium electron-hole dynamics in highly excited warm dense matter conditions.

  20. Pair potentials for warm dense matter and their application to x-ray Thomson scattering in aluminum and beryllium.

    PubMed

    Harbour, L; Dharma-Wardana, M W C; Klug, D D; Lewis, L J

    2016-11-01

    Ultrafast laser experiments yield increasingly reliable data on warm dense matter, but their interpretation requires theoretical models. We employ an efficient density functional neutral-pseudoatom hypernetted-chain (NPA-HNC) model with accuracy comparable to ab initio simulations and which provides first-principles pseudopotentials and pair potentials for warm-dense matter. It avoids the use of (i) ad hoc core-repulsion models and (ii) "Yukawa screening" and (iii) need not assume ion-electron thermal equilibrium. Computations of the x-ray Thomson scattering (XRTS) spectra of aluminum and beryllium are compared with recent experiments and with density-functional-theory molecular-dynamics (DFT-MD) simulations. The NPA-HNC structure factors, compressibilities, phonons, and conductivities agree closely with DFT-MD results, while Yukawa screening gives misleading results. The analysis of the XRTS data for two of the experiments, using two-temperature quasi-equilibrium models, is supported by calculations of their temperature relaxation times.

  1. Thermal density functional theory, ensemble density functional theory, and potential functional theory for warm dense matter

    NASA Astrophysics Data System (ADS)

    Pribram-Jones, Aurora

    Warm dense matter (WDM) is a high energy phase between solids and plasmas, with characteristics of both. It is present in the centers of giant planets, within the earth's core, and on the path to ignition of inertial confinement fusion. The high temperatures and pressures of warm dense matter lead to complications in its simulation, as both classical and quantum effects must be included. One of the most successful simulation methods is density functional theory-molecular dynamics (DFT-MD). Despite great success in a diverse array of applications, DFT-MD remains computationally expensive and it neglects the explicit temperature dependence of electron-electron interactions known to exist within exact DFT. Finite-temperature density functional theory (FT DFT) is an extension of the wildly successful ground-state DFT formalism via thermal ensembles, broadening its quantum mechanical treatment of electrons to include systems at non-zero temperatures. Exact mathematical conditions have been used to predict the behavior of approximations in limiting conditions and to connect FT DFT to the ground-state theory. An introduction to FT DFT is given within the context of ensemble DFT and the larger field of DFT is discussed for context. Ensemble DFT is used to describe ensembles of ground-state and excited systems. Exact conditions in ensemble DFT and the performance of approximations depend on ensemble weights. Using an inversion method, exact Kohn-Sham ensemble potentials are found and compared to approximations. The symmetry eigenstate Hartree-exchange approximation is in good agreement with exact calculations because of its inclusion of an ensemble derivative discontinuity. Since ensemble weights in FT DFT are temperature-dependent Fermi weights, this insight may help develop approximations well-suited to both ground-state and FT DFT. A novel, highly efficient approach to free energy calculations, finite-temperature potential functional theory, is derived, which has the

  2. The glass and jamming transitions in dense granular matter

    NASA Astrophysics Data System (ADS)

    Coulais, Corentin; Candelier, Raphaël; Dauchot, Olivier

    2013-06-01

    Everyday life tells us that matter acquires rigidity either when it cools down, like lava flows which turn into solid rocks, or when it is compacted, like tablets simply formed by powder compression. As suggested by these examples, solidification is not the sole privilege of crystals but also happens for disordered media such as glass formers, granular media, foams, emulsions and colloidal suspensions. Fifteen years ago the "Jamming paradigm" emerged to encompass in a unique framework the glass transition and the emergence of yield stress, two challenging issues in modern condensed matter physics. One must realize how bold this proposal was, given that the glass transition is a finite temperature transition governing the dynamical properties of supercooled liquids, while Jamming is essentially a zero temperature, zero external stress and purely geometric transition which occurs when a given packing of particles reaches the maximum compression state above which particles start to overlap. More recently, the observation of remarkable scaling properties on the approach to jamming led to the conjecture that this zero temperature "critical point" could determine the properties of dense particle systems within a region of the parameter space to be determined, which in principle could include thermal and stressed systems. Fifteen years of intense theoretical and experimental work later, what have we learned about Jamming and glassy dynamics? In this paper, we discuss these issues in the light of the experiments we have been conducting with vibrated grains.

  3. Optical Response of Warm Dense Matter Using Real-Time Electron Dynamics

    NASA Astrophysics Data System (ADS)

    Baczewski, Andrew; Shulenburger, Luke; Desjarlais, Michael; Magyar, Rudolph

    2014-03-01

    The extreme temperatures and solid-like densities in warm dense matter present a unique challenge for theory, wherein neither conventional models from condensed matter nor plasma physics capture all of the relevant phenomenology. While Kubo-Greenwood DFT calculations have proven capable of reproducing optical properties of WDM, they require a significant number of virtual orbitals to reach convergence due to their perturbative nature. Real-time TDDFT presents a complementary framework with a number of computationally favorable properties, including reduced cost complexity and better scalability, and has been used to reproduce the optical response of finite and ordered extended systems. We will describe the use of Ehrenfest-TDDFT to evolve coupled electron-nuclear dynamics in WDM systems, and the subsequent evaluation of optical response functions from the real-time electron dynamics. The advantages and disadvantages of this approach will be discussed relative to the current state-of-the-art. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Security Administration under contract DE-AC04-94AL85000.

  4. Hot and dense matter beyond relativistic mean field theory

    NASA Astrophysics Data System (ADS)

    Zhang, Xilin; Prakash, Madappa

    2016-05-01

    Properties of hot and dense matter are calculated in the framework of quantum hadrodynamics by including contributions from two-loop (TL) diagrams arising from the exchange of isoscalar and isovector mesons between nucleons. Our extension of mean field theory (MFT) employs the same five density-independent coupling strengths which are calibrated using the empirical properties at the equilibrium density of isospin-symmetric matter. Results of calculations from the MFT and TL approximations are compared for conditions of density, temperature, and proton fraction encountered in the study of core-collapse supernovae, young and old neutron stars, and mergers of compact binary stars. The TL results for the equation of state (EOS) of cold pure neutron matter at sub- and near-nuclear densities agree well with those of modern quantum Monte Carlo and effective field-theoretical approaches. Although the high-density EOS in the TL approximation for cold and β -equilibrated neutron-star matter is substantially softer than its MFT counterpart, it is able to support a 2 M⊙ neutron star required by recent precise determinations. In addition, radii of 1.4 M⊙ stars are smaller by ˜1 km than those obtained in MFT and lie in the range indicated by analysis of astronomical data. In contrast to MFT, the TL results also give a better account of the single-particle or optical potentials extracted from analyses of medium-energy proton-nucleus and heavy-ion experiments. In degenerate conditions, the thermal variables are well reproduced by results of Landau's Fermi-liquid theory in which density-dependent effective masses feature prominently. The ratio of the thermal components of pressure and energy density expressed as Γth=1 +(Pth/ɛth) , often used in astrophysical simulations, exhibits a stronger dependence on density than on proton fraction and temperature in both MFT and TL calculations. The prominent peak of Γth at supranuclear density found in MFT is, however, suppressed in

  5. Comparison of electron transport calculations in warm dense matter using the Ziman formula

    DOE PAGES

    Burrill, D. J.; Feinblum, D. V.; Charest, M. R. J.; ...

    2016-02-10

    The Ziman formulation of electrical conductivity is tested in warm and hot dense matter using the pseudo-atom molecular dynamics method. Several implementation options that have been widely used in the literature are systematically tested through a comparison to the accurate, but expensive Kohn–Sham density functional theory molecular dynamics (KS-DFT-MD) calculations. As a result, the comparison is made for several elements and mixtures and for a wide range of temperatures and densities, and reveals a preferred method that generally gives very good agreement with the KS-DFT-MD results, but at a fraction of the computational cost.

  6. Molecular dynamics for dense matter

    NASA Astrophysics Data System (ADS)

    Maruyama, Toshiki; Watanabe, Gentaro; Chiba, Satoshi

    2012-08-01

    We review a molecular dynamics method for nucleon many-body systems called quantum molecular dynamics (QMD), and our studies using this method. These studies address the structure and the dynamics of nuclear matter relevant to neutron star crusts, supernova cores, and heavy-ion collisions. A key advantage of QMD is that we can study dynamical processes of nucleon many-body systems without any assumptions about the nuclear structure. First, we focus on the inhomogeneous structures of low-density nuclear matter consisting not only of spherical nuclei but also of nuclear "pasta", i.e., rod-like and slab-like nuclei. We show that pasta phases can appear in the ground and equilibrium states of nuclear matter without assuming nuclear shape. Next, we show our simulation of compression of nuclear matter which corresponds to the collapsing stage of supernovae. With the increase in density, a crystalline solid of spherical nuclei changes to a triangular lattice of rods by connecting neighboring nuclei. Finally, we discuss fragment formation in expanding nuclear matter. Our results suggest that a generally accepted scenario based on the liquid-gas phase transition is not plausible at lower temperatures.

  7. Propagation in compressed matter of hot electrons created by short intense lasers

    NASA Astrophysics Data System (ADS)

    Batani, D.; Bernardinello, A.; Masella, V.; Pisani, F.; Koenig, M.; Krishnan, J.; Benuzzi, A.; Ellwi, S.; Hall, T.; Norreys, P.; Djaoui, A.; Neely, D.; Rose, S.; Fews, P.; Key, M.

    1998-02-01

    We performed the first experimental study of propagation in compressed matter of hot electrons created by a short pulse intense laser. The experiment has been carried out with the VULCAN laser at Rutherford compressing plastic targets with two ns laser beams at an intensity ⩾1014W/cm2. A CPA beam with an intensity ⩾1016W/cm2 irradiated the rear side of the target and created hot electrons propagating through the compressed matter. K-α emission was used as diagnostics of hot electron penetration by putting a chloride plastic layer inside the target.

  8. Atomistic study of mixing at high Z / low Z interfaces at Warm Dense Matter Conditions

    NASA Astrophysics Data System (ADS)

    Haxhimali, Tomorr; Glosli, James; Rudd, Robert; Lawrence Livermore National Laboratory Team

    2016-10-01

    We use atomistic simulations to study different aspects of mixing occurring at an initially sharp interface of high Z and low Z plasmas in the Warm/Hot Dense Matter regime. We consider a system of Diamond (the low Z component) in contact with Ag (the high Z component), which undergoes rapid isochoric heating from room temperature up to 10 eV, rapidly changing the solids into warm dense matter at solid density. We simulate the motion of ions via the screened Coulomb potential. The electric field, the electron density and ionizations level are computed on the fly by solving Poisson equation. The spatially varying screening lengths computed from the electron cloud are included in this effective interaction; the electrons are not simulated explicitly. We compute the electric field generated at the Ag-C interface as well as the dynamics of the ions during the mixing process occurring at the plasma interface. Preliminary results indicate an anomalous transport of high Z ions (Ag) into the low Z component (C); a phenomenon that is partially related to the enhanced transport of ions due to the generated electric field. These results are in agreement with recent experimental observation on Au-diamond plasma interface. This work was performed under the auspices of the US Dept. of Energy by Lawrence Livermore National Security, LLC under Contract DE-AC52-07NA27344.

  9. Computational study of hot electron generation and energy transport in intense laser produced hot dense matter

    NASA Astrophysics Data System (ADS)

    Mishra, Rohini

    Present ultra high power lasers are capable of producing high energy density (HED) plasmas, in controlled way, with a density greater than solid density and at a high temperature of keV (1 keV ˜ 11,000,000° K). Matter in such extreme states is particularly interesting for (HED) physics such as laboratory studies of planetary and stellar astrophysics, laser fusion research, pulsed neutron source etc. To date however, the physics in HED plasma, especially, the energy transport, which is crucial to realize applications, has not been understood well. Intense laser produced plasmas are complex systems involving two widely distinct temperature distributions and are difficult to model by a single approach. Both kinetic and collisional process are equally important to understand an entire process of laser-solid interaction. By implementing atomic physics models, such as collision, ionization, and radiation damping, self consistently, in state-of-the-art particle-in-cell code (PICLS) has enabled to explore the physics involved in the HED plasmas. Laser absorption, hot electron transport, and isochoric heating physics in laser produced hot dense plasmas are studied with a help of PICLS simulations. In particular, a novel mode of electron acceleration, namely DC-ponderomotive acceleration, is identified in the super intense laser regime which plays an important role in the coupling of laser energy to a dense plasma. Geometric effects on hot electron transport and target heating processes are examined in the reduced mass target experiments. Further, pertinent to fast ignition, laser accelerated fast electron divergence and transport in the experiments using warm dense matter (low temperature plasma) is characterized and explained.

  10. Stable solitary waves in super dense plasmas at external magnetic fields

    NASA Astrophysics Data System (ADS)

    Ghaani, Azam; Javidan, Kurosh; Sarbishaei, Mohsen

    2015-07-01

    Propagation of localized waves in a Fermi-Dirac distributed super dense matter at the presence of strong external magnetic fields is studied using the reductive perturbation method. We have shown that stable solitons can be created in such non-relativistic fluids in the presence of an external magnetic field. Such solitary waves are governed by the Zakharov-Kuznetsov (ZK) equation. Properties of solitonic solutions are studied in media with different values of background mass density and strength of magnetic field.

  11. The origin of rotation, dense matter physics and all that: a tribute to Pavle Savić.

    NASA Astrophysics Data System (ADS)

    Čelebonović, V.

    1995-04-01

    This is a review of the main physical ideas and examples of applicability in astrophysics and pure physics of a semiclassical theory of dense matter proposed by Pavle Savićand Radivoje Kašanin in the early sixties. A hypothesis, advanced by Savić with the aim of solving the problem of the origin of rotation of celestial bodies, will also be discussed. The paper is dedicated to the memory of Pavle Savić.

  12. Electron-ion temperature equilibration in warm dense tantalum

    DOE PAGES

    Doppner, T; LePape, S.; Ma, T.; ...

    2014-11-05

    We present measurements of electron-ion temperature equilibration in proton-heated tantalum, under warm dense matter conditions. Our results agree with theoretical predictions for metals calculated using input data from ab initio simulations. Furthermore, the fast relaxation observed in the experiment contrasts with much longer equilibration times found in proton heated carbon, indicating that the energy flow pathways in warm dense matter are far from being fully understood.

  13. Variational Theory of Hot Dense Matter

    ERIC Educational Resources Information Center

    Mukherjee, Abhishek

    2009-01-01

    We develop a variational theory of hot nuclear matter in neutron stars and supernovae. It can also be used to study charged, hot nuclear matter which may be produced in heavy-ion collisions. This theory is a generalization of the variational theory of cold nuclear and neutron star matter based on realistic models of nuclear forces and pair…

  14. Scalar pseudo-Nambu-Goldstone boson in nuclei and dense nuclear matter

    NASA Astrophysics Data System (ADS)

    Lee, Hyun Kyu; Paeng, Won-Gi; Rho, Mannque

    2015-12-01

    The notion that the scalar listed as f0(500 ) in the particle data booklet is a pseudo-Nambu-Goldstone (NG) boson of spontaneously broken scale symmetry, explicitly broken by a small departure from an infrared fixed point, is explored in nuclear dynamics. This notion—which puts the scalar (which we shall identify as the "dilaton") on the same footing as the pseudoscalar pseudo-NG bosons, i.e., octet π , while providing a simple explanation for the Δ I =1 /2 rule for kaon decay—generalizes the standard chiral perturbation theory (χ PT ) to "scale chiral perturbation theory," denoted χPT σ , with one infrared mass scale for both symmetries, with the σ figuring as a chiral singlet NG mode in the nonstrange sector. Applied to nuclear dynamics, it is seen to provide answers to various hitherto unclarified nuclear phenomena, such as the success of one-boson-exchange potentials, the large cancellation of a strongly attractive scalar potential by a strongly repulsive vector potential in relativistic mean-field theory of nuclear systems and in-medium QCD sum rules, the interplay of the dilaton and the vector meson ω in dense Skyrmion matter, the Bogomol'nyi-Prasad-Sommerfeld Skyrmion structure of nuclei accounting for small binding energies of medium-heavy nuclei, and the suppression of hyperon degrees of freedom in compact-star matter.

  15. Sao Paulo potential as a tool for calculating S factors of fusion reactions in dense stellar matter

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gasques, L. R.; Beard, M.; Wiescher, M.

    2007-10-15

    The goal of this paper is to test and justify the use of the Sao Paulo potential model for calculating astrophysical S factors for reactions involving stable and neutron-rich nuclei. In particular, we focus on the theoretical description of S factors at low energies. This is important for evaluating the reaction rates in dense stellar matter. We calculate the S factors for a number of reactions ({sup 16}O+{sup 16}O, {sup 20}O+{sup 20}O, {sup 20}O+{sup 26}Ne, {sup 20}O+{sup 32}Mg, {sup 26}Ne+{sup 26}Ne, {sup 26}Ne+{sup 32}Mg, {sup 32}Mg+{sup 32}Mg, {sup 22}O+{sup 22}O, {sup 24}O+{sup 24}O) with the Sao Paulo potential in themore » framework of a one-dimensional barrier penetration model. This approach can be easily applied for many other reactions involving different isotopes. To test the consistency of the model predictions, we compare our calculations with those performed within the coupled-channels and fermionic molecular dynamics models. Calculated S factors are parametrized by a simple analytic formula. The main properties and uncertainties of reaction rates (appropriate to dense matter in cores of massive white dwarfs and crusts of accreting neutron stars) are outlined.« less

  16. Effective model approach to the dense state of QCD matter

    NASA Astrophysics Data System (ADS)

    Fukushima, Kenji

    2011-12-01

    The first-principle approach to the dense state of QCD matter, i.e. the lattice-QCD simulation at finite baryon density, is not under theoretical control for the moment. The effective model study based on QCD symmetries is a practical alternative. However the model parameters that are fixed by hadronic properties in the vacuum may have unknown dependence on the baryon chemical potential. We propose a new prescription to constrain the effective model parameters by the matching condition with the thermal Statistical Model. In the transitional region where thermal quantities blow up in the Statistical Model, deconfined quarks and gluons should smoothly take over the relevant degrees of freedom from hadrons and resonances. We use the Polyakov-loop coupled Nambu-Jona-Lasinio (PNJL) model as an effective description in the quark side and show how the matching condition is satisfied by a simple ansäatz on the Polyakov loop potential. Our results favor a phase diagram with the chiral phase transition located at slightly higher temperature than deconfinement which stays close to the chemical freeze-out points.

  17. Kaon condensation in dense matter

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Carlson, J.; Heiselberg, H.; Pandharipande, V. R.

    The kaon energy in neutron matter is calculated analytically with the Klein-Gordon equation, by making a Wigner-Seitz cell approximation and employing a K{sup -}N square well potential. The transition from the low density Lenz potential, proportional to scattering length, to the high density Hartree potential is found to begin at fairly low densities. Exact nonrelativistic calculations of the kaon energy in a simple cubic crystal of neutrons are used to test the Wigner-Seitz and the Ericson-Ericson approximation methods. In this case the frequently used Erickson-Erickson approximation is found to be fairly accurate up to twice nuclear matter density. All themore » calculations indicate that by {approx}4 times nuclear matter density the Hartree limit is reached. We also show that in the Hartree limit the energy of zero momentum kaons does not have relativistic energy dependent factors present in the low density expansions. The results indicate that the density for kaon condensation is higher than previously estimated.« less

  18. Unified first principles description from warm dense matter to ideal ionized gas plasma: electron-ion collisions induced friction.

    PubMed

    Dai, Jiayu; Hou, Yong; Yuan, Jianmin

    2010-06-18

    Electron-ion interactions are central to numerous phenomena in the warm dense matter (WDM) regime and at higher temperature. The electron-ion collisions induced friction at high temperature is introduced in the procedure of ab initio molecular dynamics using the Langevin equation based on density functional theory. In this framework, as a test for Fe and H up to 1000 eV, the equation of state and the transition of electronic structures of the materials with very wide density and temperature can be described, which covers a full range of WDM up to high energy density physics. A unified first principles description from condensed matter to ideal ionized gas plasma is constructed.

  19. Warm Dense Matter Demonstrating Non-Drude Conductivity from Observations of Nonlinear Plasmon Damping

    NASA Astrophysics Data System (ADS)

    Witte, Bastian B. L.

    2017-10-01

    The thermal and electrical conductivity, equation of state and the spectral opacity in warm dense matter (WDM) are essential properties for modeling, e.g., fusion experiments or the magnetic field generation in planets. In the last decade it has been shown that x-ray Thomson scattering (XRTS) is an effective tool to determine plasma parameters like temperature and density in the WDM regime. Recently, the electrical conductivity was extracted from XRTS experiments for the first time. The spectrally resolved scattering data of aluminum, isochorically heated by the Linac Coherent Light Source (LCLS), show strong dependence on electron correlations. Therefore, the damping of plasmons, the collective electron oscillations, has to be treated beyond perturbation theory. We present results for the dynamic transport properties in warm dense aluminum using density-functional-theory molecular dynamics (DFT-MD) simulations. The choice of the exchange-correlation (XC) functional, describing the interactions in the electronic subsystem, has significant impact on the ionization energy of bound electrons and the dynamic dielectric function. Our newly developed method for the calculation of XRTS signals including plasmon and bound-free transitions is based on transition matrix elements together with ionic contributions using uniquely DFT-MD simulations. The results show excellent agreement with the LCLS data if hybrid functionals are applied. The experimental finding of nonlinear plasmon damping is caused by the non-Drude conductivity in warm dense aluminum. Here, we show further validation by comparing with x-ray absorption data. These findings enable new insights into the impact of XC functionals on calculated properties of WDM and allow detailed predictions for future experiments at the unprecedented densities on the NIF. This work was performed in collaboration with P. Sperling, S.H. Glenzer, R. Redmer and was supported by the DFG via the Collaborative Research Center SFB 652

  20. Exploring warm dense matter using quantum molecular dynamics

    NASA Astrophysics Data System (ADS)

    Clérouin, J.; Mazevet, S.

    2006-06-01

    For dense plasmas produced in shock experiments, the influence of the media on the isolated atomic properties can no longer be treated as a perturbation and conventional atomic physics approaches usually fail. Recently, quantum molecular dynamics (QMD) has been used to successfully predict static, dynamical and optical properties in this regime within the framework of a first principle method. In this short report, we illustrate the usefulness of the method for dense plasmas with a few selected examples: the equation of state of liquid deuterium, the electrical properties of expanded metals, the optical properties of shocked insulators, and the interaction of femto-second lasers with gold thin films.

  1. The viscosity to entropy ratio: From string theory motivated bounds to warm dense matter

    DOE PAGES

    Faussurier, G.; Libby, S. B.; Silvestrelli, P. L.

    2014-07-04

    Here, we study the ratio of viscosity to entropy density in Yukawa one-component plasmas as a function of coupling parameter at fixed screening, and in realistic warm dense matter models as a function of temperature at fixed density. In these two situations, the ratio is minimized for values of the coupling parameters that depend on screening, and for temperatures that in turn depend on density and material. In this context, we also examine Rosenfeld arguments relating transport coefficients to excess reduced entropy for Yukawa one-component plasmas. For these cases we show that this ratio is always above the lower-bound conjecturemore » derived from string theory ideas.« less

  2. Equation of state of dense nuclear matter and neutron star structure from nuclear chiral interactions

    NASA Astrophysics Data System (ADS)

    Bombaci, Ignazio; Logoteta, Domenico

    2018-02-01

    Aims: We report a new microscopic equation of state (EOS) of dense symmetric nuclear matter, pure neutron matter, and asymmetric and β-stable nuclear matter at zero temperature using recent realistic two-body and three-body nuclear interactions derived in the framework of chiral perturbation theory (ChPT) and including the Δ(1232) isobar intermediate state. This EOS is provided in tabular form and in parametrized form ready for use in numerical general relativity simulations of binary neutron star merging. Here we use our new EOS for β-stable nuclear matter to compute various structural properties of non-rotating neutron stars. Methods: The EOS is derived using the Brueckner-Bethe-Goldstone quantum many-body theory in the Brueckner-Hartree-Fock approximation. Neutron star properties are next computed solving numerically the Tolman-Oppenheimer-Volkov structure equations. Results: Our EOS models are able to reproduce the empirical saturation point of symmetric nuclear matter, the symmetry energy Esym, and its slope parameter L at the empirical saturation density n0. In addition, our EOS models are compatible with experimental data from collisions between heavy nuclei at energies ranging from a few tens of MeV up to several hundreds of MeV per nucleon. These experiments provide a selective test for constraining the nuclear EOS up to 4n0. Our EOS models are consistent with present measured neutron star masses and particularly with the mass M = 2.01 ± 0.04 M⊙ of the neutron stars in PSR J0348+0432.

  3. Fluorescence and absorption spectroscopy for warm dense matter studies and ICF plasma diagnostics

    NASA Astrophysics Data System (ADS)

    Hansen, Stephanie

    2017-10-01

    The burning core of an inertial confinement fusion (ICF) plasma at stagnation is surrounded by a shell of warm, dense matter whose properties are difficult both to model (due to a complex interplay of thermal, degeneracy, and strong coupling effects) and to diagnose (due to low emissivity and high opacity). We demonstrate a promising technique to study the warm dense shells of ICF plasmas based on the fluorescence emission of dopants or impurities in the shell material. This emission, which is driven by x-rays produced in the hot core, exhibits signature changes in response to compression and heating. High-resolution measurements of absorption and fluorescence features can refine our understanding of the electronic structure of material under high compression, improve our models of density-driven phenomena such as ionization potential depression and plasma polarization shifts, and help diagnose shell density, temperature, mass distribution, and residual motion in ICF plasmas at stagnation. Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA-0003525. This work was supported by the U.S. Department of Energy, Office of Science Early Career Research Program, Office of Fusion Energy Sciences under FWP-14-017426.

  4. X-Ray Spectroscopies of Warm Dense Matter

    NASA Astrophysics Data System (ADS)

    Hoidn, Oliver

    This dissertation provides a perspective on the role of x-ray spectroscopy and diffraction diagnostics in experimental studies of warm dense matter (WDM). The primary focus of the work I discuss is the development of techniques to measure the structure and state variables of laboratory-generated WDM with a view towards both phenomenlogy and placing contraints on theoretical models. I present techniques adapted to two experimental venues for WDM studies: large-scale laser plasma facilities and x-ray free electron lasers. My focus is on the latter, in the context of which I have studied a dose enhancement technique that exploits nonlocal heat transport in nanostructured targets and considered several aspects of optimizing x-ray diffraction measurements. This work came into play in beam runs at the Linac Coherent Light Source (LCLS) in which my group performed x-ray diffraction studies of several materials heated to eV-scale temperatures. The results from these experiments include confirmation of the persistence of long-range crystalline order upon heating of metal oxides to tens of eV temperarures on the 40 fs timescale. One material, MgO, additionally manifested a surprising anomalous early onset in delocalization of valence charge density, contradicting predictions of all models based on either ground state electronic structure or (high-energy density) plasma physics. This particular result outlines a future path for studies of ordered insulators heated to temperatures on the order of the band gap. Such experiments will offer strong tests of electronic strucure theory, implementing a scientific approach that sees measurement of real-space charge density via x-ray diffraction (XRD) as a particularly effectve means to constrain density functional theory (DFT)-based modeling of the solid state/plasma transitional regime.

  5. Dense baryon matter with isospin and chiral imbalance in the framework of a NJL4 model at large Nc: Duality between chiral symmetry breaking and charged pion condensation

    NASA Astrophysics Data System (ADS)

    Khunjua, T. G.; Klimenko, K. G.; Zhokhov, R. N.

    2018-03-01

    In this paper the phase structure of dense quark matter has been investigated at zero temperature in the presence of baryon, isospin and chiral isospin chemical potentials in the framework of massless (3 +1 )-dimensional Nambu-Jona-Lasinio model with two quark flavors. It has been shown that in the large-Nc limit (Nc is the number of colors of quarks) there exists a duality correspondence between the chiral symmetry breaking phase and the charged pion condensation one. The key conclusion of our studies is the fact that chiral isospin chemical potential generates charged pion condensation in dense quark matter with isotopic asymmetry.

  6. Visualization of the ultrafast structural phase transitions in warm dense matter

    NASA Astrophysics Data System (ADS)

    Mo, Mianzhen

    2017-10-01

    It is still a great challenge to obtain real-time atomistic-scale information on the structural phase transitions that lead to warm dense matter state. Recent advances in ultrafast electron diffraction (UED) techniques have opened up exciting prospects to unravel the mechanisms of solid-liquid phase transitions under these extreme non-equilibrium conditions. Here we report on precise measurements of melt time dependency on laser excitation energy density that resolve for the first time the transition from heterogeneous to homogeneous melting. This transition appears in both polycrystalline and single-crystal gold nanofilms with distinct measurable differences. These results test predictions from molecular-dynamics simulations with different interatomic potential models. These data further deliver accurate structure factor data to large wavenumbers that allow us to constrain electron-ion equilibration constants. Our results demonstrate electron-phonon coupling strength much weaker than DFT calculations, and contrary to previous results, provide evidence for bond softening. This work is supported by DOE Office of Science, Fusion Energy Science under FWP 100182, and the DOE BES Accelerator and Detector R&D program.

  7. Short intense ion pulses for materials and warm dense matter research

    DOE PAGES

    Seidl, Peter A.; Persaud, Arun; Waldron, William L.; ...

    2015-08-14

    We have commenced experiments with intense short pulses of ion beams on the Neutralized Drift Compression Experiment-II at Lawrence Berkeley National Laboratory, by generating beam spots size with radius r<1 mm within 2 ns FWHM and approximately 10 10 ions/pulse. To enable the short pulse durations and mm-scale focal spot radii, the 1.2 MeV Li + ion beam is neutralized in a 1.6-meter drift compression section located after the last accelerator magnet. An 8-Tesla short focal length solenoid compresses the beam in the presence of the large volume plasma near the end of this section before the target. The scientificmore » topics to be explored are warm dense matter, the dynamics of radiation damage in materials, and intense beam and beam-plasma physics including selected topics of relevance to the development of heavy-ion drivers for inertial fusion energy. Finally, we describe the accelerator commissioning and time-resolved ionoluminescence measurements of yttrium aluminum perovskite using the fully integrated accelerator and neutralized drift compression components.« less

  8. Short intense ion pulses for materials and warm dense matter research

    NASA Astrophysics Data System (ADS)

    Seidl, Peter A.; Persaud, Arun; Waldron, William L.; Barnard, John J.; Davidson, Ronald C.; Friedman, Alex; Gilson, Erik P.; Greenway, Wayne G.; Grote, David P.; Kaganovich, Igor D.; Lidia, Steven M.; Stettler, Matthew; Takakuwa, Jeffrey H.; Schenkel, Thomas

    2015-11-01

    We have commenced experiments with intense short pulses of ion beams on the Neutralized Drift Compression Experiment-II at Lawrence Berkeley National Laboratory, by generating beam spots size with radius r<1 mm within 2 ns FWHM and approximately 1010 ions/pulse. To enable the short pulse durations and mm-scale focal spot radii, the 1.2 MeV Li+ ion beam is neutralized in a 1.6-meter drift compression section located after the last accelerator magnet. An 8-Tesla short focal length solenoid compresses the beam in the presence of the large volume plasma near the end of this section before the target. The scientific topics to be explored are warm dense matter, the dynamics of radiation damage in materials, and intense beam and beam-plasma physics including selected topics of relevance to the development of heavy-ion drivers for inertial fusion energy. Here we describe the accelerator commissioning and time-resolved ionoluminescence measurements of yttrium aluminum perovskite using the fully integrated accelerator and neutralized drift compression components.

  9. Hydrogen and helium under high pressure - A case for a classical theory of dense matter

    NASA Astrophysics Data System (ADS)

    Celebonovic, Vladan

    1989-06-01

    When subject to high pressure, H2 and He-3 are expected to undergo phase transitions, and to become metallic at a sufficiently high pressure. Using a semiclassical theory of dense matter proposed by Savic and Kasanin, calculations of phase transition and metallization pressure have been performed for these two materials. In hydrogen, metallization occurs at p(M) = (3.0 + or - 0.2) Mbar, while for helium the corresponding value is (106 + or - 1) Mbar. A phase transition occurs in helium at p(tr) = (10.0 + or - 0.4) Mbar. These values are close to the results obtainable by more rigorous methods. Possibilities of experimental verification of the calculations are briefly discussed.

  10. Average-atom model for two-temperature states and ionic transport properties of aluminum in the warm dense matter regime

    NASA Astrophysics Data System (ADS)

    Hou, Yong; Fu, Yongsheng; Bredow, Richard; Kang, Dongdong; Redmer, Ronald; Yuan, Jianmin

    2017-03-01

    The average-atom model combined with the hyper-netted chain approximation is an efficient tool for electronic and ionic structure calculations for warm dense matter. Here we generalize this method in order to describe non-equilibrium states with different electron and ion temperature as produced in laser-matter interactions on ultra-short time scales. In particular, the electron-ion and ion-ion correlation effects are considered when calculating the electron structure. We derive an effective ion-ion pair-potential using the electron densities in the framework of temperature-depended density functional theory. Using this ion-ion potential we perform molecular dynamics simulations in order to determine the ionic transport properties such as the ionic diffusion coefficient and the shear viscosity through the ionic velocity autocorrelation functions.

  11. Space-Time Characterization of Laser Plasma Interactions in the Warm Dense Matter Regime

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cao, L F; Uschmann, I; Forster, E

    2008-04-30

    Laser plasma interaction experiments have been performed using a fs Titanium Sapphire laser. Plasmas have been generated from planar PMMA targets using single laser pulses with 3.3 mJ pulse energy, 50 fs pulse duration at 800 nm wavelength. The electron density distributions of the plasmas in different delay times have been characterized by means of Nomarski Interferometry. Experimental data were compared with hydrodynamic simulation. First results to characterize the plasma density and temperature as a function of space and time are obtained. This work aims to generate plasmas in the warm dense matter (WDM) regime at near solid-density in anmore » ultra-fast laser target interaction process. Plasmas under these conditions can serve as targets to develop x-ray Thomson scattering as a plasma diagnostic tool, e.g., using the VUV free-electron laser (FLASH) at DESY Hamburg.« less

  12. Compton scattering measurements from dense plasmas

    DOE PAGES

    Glenzer, S. H.; Neumayer, P.; Doppner, T.; ...

    2008-06-12

    Here, Compton scattering techniques have been developed for accurate measurements of densities and temperatures in dense plasmas. One future challenge is the application of this technique to characterize compressed matter on the National Ignition Facility where hydrogen and beryllium will approach extremely dense states of matter of up to 1000 g/cc. In this regime, the density, compressibility, and capsule fuel adiabat may be directly measured from the Compton scattered spectrum of a high-energy x-ray line source. Specifically, the scattered spectra directly reflect the electron velocity distribution. In non-degenerate plasmas, the width provides an accurate measure of the electron temperatures, whilemore » in partially Fermi degenerate systems that occur in laser-compressed matter it provides the Fermi energy and hence the electron density. Both of these regimes have been accessed in experiments at the Omega laser by employing isochorically heated solid-density beryllium and moderately compressed beryllium foil targets. In the latter experiment, compressions by a factor of 3 at pressures of 40 Mbar have been measured in excellent agreement with radiation hydrodynamic modeling.« less

  13. Dense blocks of energetic ions driven by multi-petawatt lasers

    PubMed Central

    Weng, S. M.; Liu, M.; Sheng, Z. M.; Murakami, M.; Chen, M.; Yu, L. L.; Zhang, J.

    2016-01-01

    Laser-driven ion accelerators have the advantages of compact size, high density, and short bunch duration over conventional accelerators. Nevertheless, it is still challenging to simultaneously enhance the yield and quality of laser-driven ion beams for practical applications. Here we propose a scheme to address this challenge via the use of emerging multi-petawatt lasers and a density-modulated target. The density-modulated target permits its ions to be uniformly accelerated as a dense block by laser radiation pressure. In addition, the beam quality of the accelerated ions is remarkably improved by embedding the target in a thick enough substrate, which suppresses hot electron refluxing and thus alleviates plasma heating. Particle-in-cell simulations demonstrate that almost all ions in a solid-density plasma of a few microns can be uniformly accelerated to about 25% of the speed of light by a laser pulse at an intensity around 1022 W/cm2. The resulting dense block of energetic ions may drive fusion ignition and more generally create matter with unprecedented high energy density. PMID:26924793

  14. Combined Constraints on the Equation of State of Dense Neutron-rich Matter from Terrestrial Nuclear Experiments and Observations of Neutron Stars

    NASA Astrophysics Data System (ADS)

    Zhang, Nai-Bo; Li, Bao-An; Xu, Jun

    2018-06-01

    Within the parameter space of the equation of state (EOS) of dense neutron-rich matter limited by existing constraints mainly from terrestrial nuclear experiments, we investigate how the neutron star maximum mass M max > 2.01 ± 0.04 M ⊙, radius 10.62 km < R 1.4 < 12.83 km and tidal deformability Λ1.4 ≤ 800 of canonical neutron stars together constrain the EOS of dense neutron-rich nucleonic matter. While the 3D parameter space of K sym (curvature of nuclear symmetry energy), J sym, and J 0 (skewness of the symmetry energy and EOS of symmetric nuclear matter, respectively) is narrowed down significantly by the observational constraints, more data are needed to pin down the individual values of K sym, J sym, and J 0. The J 0 largely controls the maximum mass of neutron stars. While the EOS with J 0 = 0 is sufficiently stiff to support neutron stars as massive as 2.37 M ⊙, supporting the hypothetical ones as massive as 2.74 M ⊙ (composite mass of GW170817) requires J 0 to be larger than its currently known maximum value of about 400 MeV and beyond the causality limit. The upper limit on the tidal deformability of Λ1.4 = 800 from the recent observation of GW170817 is found to provide upper limits on some EOS parameters consistent with but far less restrictive than the existing constraints of other observables studied.

  15. Magnetic fields in turbulent quark matter and magnetar bursts

    NASA Astrophysics Data System (ADS)

    Dvornikov, Maxim

    We analyze the magnetic field evolution in dense quark matter with unbroken chiral symmetry, which can be found inside quark and hybrid stars. The magnetic field evolves owing to the chiral magnetic effect in the presence of the electroweak interaction between quarks. In our study, we also take into account the magnetohydrodynamic turbulence effects in dense quark matter. We derive the kinetic equations for the spectra of the magnetic helicity density and the magnetic energy density as well as for the chiral imbalances. On the basis of the numerical solution of these equations, we find that turbulence effects are important for the behavior of small scale magnetic fields. It is revealed that, under certain initial conditions, these magnetic fields behave similarly to the electromagnetic flashes of some magnetars. We suggest that fluctuations of magnetic fields, described in frames of our model, which are created in the central regions of a magnetized compact star, can initiate magnetar bursts.

  16. Scaling relationships for nonadiabatic energy relaxation times in warm dense matter: toward understanding the equation of state.

    PubMed

    Pradhan, Ekadashi; Magyar, Rudolph J; Akimov, Alexey V

    2016-11-30

    Understanding the dynamics of electron-ion energy transfer in warm dense (WD) matter is important to the measurement of equation of state (EOS) properties and for understanding the energy balance in dynamic simulations. In this work, we present a comprehensive investigation of nonadiabatic electron relaxation and thermal excitation dynamics in aluminum under high pressure and temperature. Using quantum-classical trajectory surface hopping approaches, we examine the role of nonadiabatic couplings and electronic decoherence in electron-nuclear energy transfer in WD aluminum. The computed timescales range from 400 fs to 4.0 ps and are consistent with existing experimental studies. We have derived general scaling relationships between macroscopic parameters of WD systems such as temperature or mass density and the timescales of energy redistribution between quantum and classical degrees of freedom. The scaling laws are supported by computational results. We show that electronic decoherence plays essential role and can change the functional dependencies qualitatively. The established scaling relationships can be of use in modelling of WD matter.

  17. Short Intense Ion Pulses for Materials and Warm Dense Matter Research

    NASA Astrophysics Data System (ADS)

    Seidl, Peter; Ji, Q.; Lidia, S. M.; Persaud, A.; Stettler, M.; Takakuwa, J. H.; Waldron, W. L.; Schenkel, T.; Barnard, J. J.; Friedman, A.; Grote, D. P.; Davidson, R. C.; Gilson, E. P.; Kaganovich, I. D.

    2015-11-01

    We have commenced experiments with intense short pulses of ion beams on the Neutralized Drift Compression Experiment-II at Lawrence Berkeley National Laboratory, by generating beam spots size with radius r <1 mm within 2 ns FWHM and approximately 1010 ions/pulse. To enable the short pulse durations and mm-scale focal spot radii, the 1.2 MeV Li + ion beam is neutralized in a 1.6-meter drift compression section located after the last accelerator magnet. An 8-Tesla short focal length solenoid compresses the beam in the presence of the large volume plasma near the end of this section before the target. The scientific topics to be explored are warm dense matter, the dynamics of radiation damage in materials, and intense beam and beam-plasma physics including selected topics of relevance to the development of heavy-ion drivers for inertial fusion energy. We will describe the accelerator commissioning and time-resolved ionoluminescence measurements of yttrium aluminium perovskite using the fully integrated accelerator and neutralized drift compression components (arXiv:1506.05839). This work was supported by the Director, Office of Science, Office of Fusion Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.

  18. Apparatus and method for creating a photonic densely-accumulated ray-point

    NASA Technical Reports Server (NTRS)

    Park, Yeonjoon (Inventor); Choi, Sang H. (Inventor); King, Glen C. (Inventor); Elliott, James R. (Inventor)

    2012-01-01

    An optical apparatus includes an optical diffraction device configured for diffracting a predetermined wavelength of incident light onto adjacent optical focal points, and a photon detector for detecting a spectral characteristic of the predetermined wavelength. One of the optical focal points is a constructive interference point and the other optical focal point is a destructive interference point. The diffraction device, which may be a micro-zone plate (MZP) of micro-ring gratings or an optical lens, generates a constructive ray point using phase-contrasting of the destructive interference point. The ray point is located between adjacent optical focal points. A method of generating a densely-accumulated ray point includes directing incident light onto the optical diffraction device, diffracting the selected wavelength onto the constructive interference focal point and the destructive interference focal point, and generating the densely-accumulated ray point in a narrow region.

  19. Time-resolved X-ray Absorption Spectroscopy for Electron Transport Study in Warm Dense Gold

    NASA Astrophysics Data System (ADS)

    Lee, Jong-Won; Bae, Leejin; Engelhorn, Kyle; Heimann, Philip; Ping, Yuan; Barbrel, Ben; Fernandez, Amalia; Beckwith, Martha Anne; Cho, Byoung-Ick; GIST Team; IBS Team; LBNL Collaboration; SLAC Collaboration; LLNL Collaboration

    2015-11-01

    The warm dense Matter represents states of which the temperature is comparable to Fermi energy and ions are strongly coupled. One of the experimental techniques to create such state in the laboratory condition is the isochoric heating of thin metal foil with femtosecond laser pulses. This concept largely relies on the ballistic transport of electrons near the Fermi-level, which were mainly studied for the metals in ambient conditions. However, they were barely investigated in warm dense conditions. We present a time-resolved x-ray absorption spectroscopy measured for the Au/Cu dual layered sample. The front Au layer was isochorically heated with a femtosecond laser pulse, and the x-ray absorption changes around L-edge of Cu, which was attached on the backside of Au, was measured with a picosecond resolution. Time delays between the heating of the `front surface' of Au layer and the alternation of x-ray spectrum of Cu attached on the `rear surface' of Au indicate the energetic electron transport mechanism through Au in the warm dense conditions. IBS (IBS-R012-D1) and the NRF (No. 2013R1A1A1007084) of Korea.

  20. Demonstration of x-ray Thomson scattering using picosecond K-α x-ray sources in the characterization of dense heated matter

    DOE PAGES

    Kritcher, A. L.; Neumayer, P.; Lee, H. J.; ...

    2008-10-31

    Here, we present K-α x-ray Thomson scattering from shock compressed matter for use as a diagnostic in determining the temperature, density, and ionization state with picosecond resolution. The development of this source as a diagnostic as well as stringent requirements for successful K-α x-ray Thomson scattering are addressed. Here, the first elastic and inelastic scattering measurements on a medium size laser facility have been observed. We present scattering data from solid density carbon plasmas with >1X 10 5 photons in the elastic peak that validate the capability of single shot characterization of warm dense matter and the ability to usemore » this scattering source at future free electron lasers and for fusion experiments at the National Ignition Facility (NIF), LLNL.« less

  1. Isochoric, isobaric, and ultrafast conductivities of aluminum, lithium, and carbon in the warm dense matter regime

    NASA Astrophysics Data System (ADS)

    Dharma-wardana, M. W. C.; Klug, D. D.; Harbour, L.; Lewis, Laurent J.

    2017-11-01

    We study the conductivities σ of (i) the equilibrium isochoric state σis, (ii) the equilibrium isobaric state σib, and also the (iii) nonequilibrium ultrafast matter state σuf with the ion temperature Ti less than the electron temperature Te. Aluminum, lithium, and carbon are considered, being increasingly complex warm dense matter systems, with carbon having transient covalent bonds. First-principles calculations, i.e., neutral-pseudoatom (NPA) calculations and density-functional theory (DFT) with molecular-dynamics (MD) simulations, are compared where possible with experimental data to characterize σic, σib, and σuf. The NPA σib is closest to the available experimental data when compared to results from DFT with MD simulations, where simulations of about 64-125 atoms are typically used. The published conductivities for Li are reviewed and the value at a temperature of 4.5 eV is examined using supporting x-ray Thomson-scattering calculations. A physical picture of the variations of σ with temperature and density applicable to these materials is given. The insensitivity of σ to Te below 10 eV for carbon, compared to Al and Li, is clarified.

  2. Visualization of expanding warm dense gold and diamond heated rapidly by laser-generated ion beams

    DOE PAGES

    Bang, W.; Albright, B. J.; Bradley, P. A.; ...

    2015-09-22

    With the development of several novel heating sources, scientists can now heat a small sample isochorically above 10,000 K. Although matter at such an extreme state, known as warm dense matter, is commonly found in astrophysics (e.g., in planetary cores) as well as in high energy density physics experiments, its properties are not well understood and are difficult to predict theoretically. This is because the approximations made to describe condensed matter or high-temperature plasmas are invalid in this intermediate regime. A sufficiently large warm dense matter sample that is uniformly heated would be ideal for these studies, but has beenmore » unavailable to date. We have used a beam of quasi-monoenergetic aluminum ions to heat gold and diamond foils uniformly and isochorically. For the first time, we visualized directly the expanding warm dense gold and diamond with an optical streak camera. Furthermore, we present a new technique to determine the initial temperature of these heated samples from the measured expansion speeds of gold and diamond into vacuum. We anticipate the uniformly heated solid density target will allow for direct quantitative measurements of equation-of-state, conductivity, opacity, and stopping power of warm dense matter, benefiting plasma physics, astrophysics, and nuclear physics.« less

  3. Visualization of expanding warm dense gold and diamond heated rapidly by laser-generated ion beams.

    PubMed

    Bang, W; Albright, B J; Bradley, P A; Gautier, D C; Palaniyappan, S; Vold, E L; Santiago Cordoba, M A; Hamilton, C E; Fernández, J C

    2015-09-22

    With the development of several novel heating sources, scientists can now heat a small sample isochorically above 10,000 K. Although matter at such an extreme state, known as warm dense matter, is commonly found in astrophysics (e.g., in planetary cores) as well as in high energy density physics experiments, its properties are not well understood and are difficult to predict theoretically. This is because the approximations made to describe condensed matter or high-temperature plasmas are invalid in this intermediate regime. A sufficiently large warm dense matter sample that is uniformly heated would be ideal for these studies, but has been unavailable to date. Here we have used a beam of quasi-monoenergetic aluminum ions to heat gold and diamond foils uniformly and isochorically. For the first time, we visualized directly the expanding warm dense gold and diamond with an optical streak camera. Furthermore, we present a new technique to determine the initial temperature of these heated samples from the measured expansion speeds of gold and diamond into vacuum. We anticipate the uniformly heated solid density target will allow for direct quantitative measurements of equation-of-state, conductivity, opacity, and stopping power of warm dense matter, benefiting plasma physics, astrophysics, and nuclear physics.

  4. Visualization of expanding warm dense gold and diamond heated rapidly by laser-generated ion beams

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bang, W.; Albright, B. J.; Bradley, P. A.

    With the development of several novel heating sources, scientists can now heat a small sample isochorically above 10,000 K. Although matter at such an extreme state, known as warm dense matter, is commonly found in astrophysics (e.g., in planetary cores) as well as in high energy density physics experiments, its properties are not well understood and are difficult to predict theoretically. This is because the approximations made to describe condensed matter or high-temperature plasmas are invalid in this intermediate regime. A sufficiently large warm dense matter sample that is uniformly heated would be ideal for these studies, but has beenmore » unavailable to date. We have used a beam of quasi-monoenergetic aluminum ions to heat gold and diamond foils uniformly and isochorically. For the first time, we visualized directly the expanding warm dense gold and diamond with an optical streak camera. Furthermore, we present a new technique to determine the initial temperature of these heated samples from the measured expansion speeds of gold and diamond into vacuum. We anticipate the uniformly heated solid density target will allow for direct quantitative measurements of equation-of-state, conductivity, opacity, and stopping power of warm dense matter, benefiting plasma physics, astrophysics, and nuclear physics.« less

  5. Visualization of expanding warm dense gold and diamond heated rapidly by laser-generated ion beams

    NASA Astrophysics Data System (ADS)

    Bang, W.; Albright, B. J.; Bradley, P. A.; Gautier, D. C.; Palaniyappan, S.; Vold, E. L.; Cordoba, M. A. Santiago; Hamilton, C. E.; Fernández, J. C.

    2015-09-01

    With the development of several novel heating sources, scientists can now heat a small sample isochorically above 10,000 K. Although matter at such an extreme state, known as warm dense matter, is commonly found in astrophysics (e.g., in planetary cores) as well as in high energy density physics experiments, its properties are not well understood and are difficult to predict theoretically. This is because the approximations made to describe condensed matter or high-temperature plasmas are invalid in this intermediate regime. A sufficiently large warm dense matter sample that is uniformly heated would be ideal for these studies, but has been unavailable to date. Here we have used a beam of quasi-monoenergetic aluminum ions to heat gold and diamond foils uniformly and isochorically. For the first time, we visualized directly the expanding warm dense gold and diamond with an optical streak camera. Furthermore, we present a new technique to determine the initial temperature of these heated samples from the measured expansion speeds of gold and diamond into vacuum. We anticipate the uniformly heated solid density target will allow for direct quantitative measurements of equation-of-state, conductivity, opacity, and stopping power of warm dense matter, benefiting plasma physics, astrophysics, and nuclear physics.

  6. Proton Beam Driven Isochoric Heating to Warm Dense Matter Conditions on Texas Petawatt

    NASA Astrophysics Data System (ADS)

    Roycroft, R.; Dyer, G. M.; McCary, E.; Jiao, X.; Bowers, B.; Bernstein, A.; Ditmire, T.; Montgomery, M.; Winget, D.; Hegelich, B. M.

    2017-10-01

    Isochoric heating of solids and gases to warm dense matter conditions is relevant to the study of equation of state as well as laboratory astrophysics, specifically heating of hydrogen gas ( 1017-1019 cm3) to 0.5-3eV for the study of white dwarf atmospheres. In a series of experiments on Texas Petawatt, we have built a platform using the petawatt laser focused softly to a large focal spot (60-70um) to generate large numbers of intermediate energy protons via TNSA, ideal for isochoric heating. We have previously used the proton beam to isochorically heat 10um aluminum foils to 20eV. This poster presents results of experiments in which low Z materials such as methane gas, carbon foams, and hydrogen are heated using this platform. We are measuring the surface brightness temperature and heating with a streaked optical pyrometer, and XUV emissions using an XUV spectrometer. Supported by NNSA cooperative agreement DE-NA0002008, the DARPA PULSE program (12-63-PULSE-FP014), and the Air Force Office of Scientific Research (FA9550-14-1-0045).

  7. Coalescence preference in densely packed microbubbles

    DOE PAGES

    Kim, Yeseul; Lim, Su Jin; Gim, Bopil; ...

    2015-01-13

    A bubble merged from two parent bubbles with different size tends to be placed closer to the larger parent. This phenomenon is known as the coalescence preference. Here we demonstrate that the coalescence preference can be blocked inside a densely packed cluster of bubbles. We utilized high-speed high-resolution X-ray microscopy to clearly visualize individual coalescence events inside densely packed microbubbles with a local packing fraction of ~40%. Thus, the surface energy release theory predicts an exponent of 5 in a relation between the relative coalescence position and the parent size ratio, whereas our observation for coalescence in densely packed microbubblesmore » shows a different exponent of 2. We believe that this result would be important to understand the reality of coalescence dynamics in a variety of packing situations of soft matter.« less

  8. Coalescence preference in densely packed microbubbles

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kim, Yeseul; Lim, Su Jin; Gim, Bopil

    A bubble merged from two parent bubbles with different size tends to be placed closer to the larger parent. This phenomenon is known as the coalescence preference. Here we demonstrate that the coalescence preference can be blocked inside a densely packed cluster of bubbles. We utilized high-speed high-resolution X-ray microscopy to clearly visualize individual coalescence events inside densely packed microbubbles with a local packing fraction of ~40%. Thus, the surface energy release theory predicts an exponent of 5 in a relation between the relative coalescence position and the parent size ratio, whereas our observation for coalescence in densely packed microbubblesmore » shows a different exponent of 2. We believe that this result would be important to understand the reality of coalescence dynamics in a variety of packing situations of soft matter.« less

  9. XFEL resonant photo-pumping of dense plasmas and dynamic evolution of autoionizing core hole states

    NASA Astrophysics Data System (ADS)

    Rosmej, F. B.; Moinard, A.; Renner, O.; Galtier, E.; Lee, J. J.; Nagler, B.; Heimann, P. A.; Schlotter, W.; Turner, J. J.; Lee, R. W.; Makita, M.; Riley, D.; Seely, J.

    2016-03-01

    Similarly to the case of LIF (Laser-Induced Fluorescence), an equally revolutionary impact to science is expected from resonant X-ray photo-pumping. It will particularly contribute to a progress in high energy density science: pumped core hole states create X-ray transitions that can escape dense matter on a 10 fs-time scale without essential photoabsorption, thus providing a unique possibility to study matter under extreme conditions. In the first proof of principle experiment at the X-ray Free Electron Laser LCLS at SCLAC [Seely, J., Rosmej, F.B., Shepherd, R., Riley, D., Lee, R.W. Proposal to Perform the 1st High Energy Density Plasma Spectroscopic Pump/Probe Experiment”, approved LCLS proposal L332 (2010)] we have successfully pumped inner-shell X-ray transitions in dense plasmas. The plasma was generated with a YAG laser irradiating solid Al and Mg targets attached to a rotating cylinder. In parallel to the optical laser beam, the XFEL was focused into the plasma plume at different delay times and pump energies. Pumped X-ray transitions have been observed with a spherically bent crystal spectrometer coupled to a Princeton CCD. By using this experimental configuration, we have simultaneously achieved extremely high spectral (λ/δλ ≈ 5000) and spatial resolution (δx≈70 μm) while maintaining high luminosity and a large spectral range covered (6.90 - 8.35 Å). By precisely measuring the variations in spectra emitted from plasma under action of XFEL radiation, we have successfully demonstrated transient X- ray pumping in a dense plasma.

  10. Dense Axion Stars.

    PubMed

    Braaten, Eric; Mohapatra, Abhishek; Zhang, Hong

    2016-09-16

    If the dark matter particles are axions, gravity can cause them to coalesce into axion stars, which are stable gravitationally bound systems of axions. In the previously known solutions for axion stars, gravity and the attractive force between pairs of axions are balanced by the kinetic pressure. The mass of these dilute axion stars cannot exceed a critical mass, which is about 10^{-14}M_{⊙} if the axion mass is 10^{-4}  eV. We study axion stars using a simple approximation to the effective potential of the nonrelativistic effective field theory for axions. We find a new branch of dense axion stars in which gravity is balanced by the mean-field pressure of the axion Bose-Einstein condensate. The mass on this branch ranges from about 10^{-20}M_{⊙} to about M_{⊙}. If a dilute axion star with the critical mass accretes additional axions and collapses, it could produce a bosenova, leaving a dense axion star as the remnant.

  11. Crystallization of dense neutron matter

    NASA Technical Reports Server (NTRS)

    Canuto, V.; Chitre, S. M.

    1974-01-01

    The equation of state for cold neutron matter at high density is studied in the t-matrix formulation, and it is shown that energetically it is convenient to have neutrons in a crystalline configuration rather than in a liquid state for values of the density exceeding 1600 Tg/cu cm. The study of the mechanical properties indicates that the system is stable against shearing stresses. A solid core in the deep interior of heavy neutron stars appears to offer the most plausible explanation of speed-ups observed in the Vela pulsar.

  12. Measurement of charged-particle stopping in warm-dense plasma

    DOE PAGES

    Zylstra, A.  B.; Frenje, J.  A.; Grabowski, P. E.; ...

    2015-05-27

    We measured the stopping of energetic protons in an isochorically-heated solid-density Be plasma with an electron temperature of ~32 eV, corresponding to moderately-coupled [(e²/a/(k BT e + E F ) ~ 0.3] and moderately-degenerate [k BT e/E F ~2] 'warm dense matter' (WDM) conditions. We present the first high-accuracy measurements of charged-particle energy loss through dense plasma, which shows an increased loss relative to cold matter, consistent with a reduced mean ionization potential. The data agree with stopping models based on an ad-hoc treatment of free and bound electrons, as well as the average-atom local-density approximation; this work is themore » first test of these theories in WDM plasma.« less

  13. Phase transitions in dense matter

    NASA Astrophysics Data System (ADS)

    Dexheimer, Veronica; Hempel, Matthias; Iosilevskiy, Igor; Schramm, Stefan

    2017-11-01

    As the density of matter increases, atomic nuclei disintegrate into nucleons and, eventually, the nucleons themselves disintegrate into quarks. The phase transitions (PT's) between these phases can vary from steep first order to smooth crossovers, depending on certain conditions. First-order PT's with more than one globally conserved charge, so-called non-congruent PT's, have characteristic differences compared to congruent PT's. In this conference proceeding we discuss the non-congruence of the quark deconfinement PT at high densities and/or temperatures relevant for heavy-ion collisions, neutron stars, proto-neutron stars, supernova explosions, and compact-star mergers.

  14. Hydrodynamic Tunneling of 440 GeV SPS protons in Solid Material: Production of Warm Dense Matter at CERN HiRadMat Facility

    NASA Astrophysics Data System (ADS)

    Tahir, Naeem Ahmad; Blanco Sancho, Juan; Schmidt, Ruediger; Shutov, Alaxander; Burkart, Florian; Wollmann, Daniel; Piriz, Antonio Roberto

    2013-10-01

    Numerical simulations have shown that the range of 7 TeV LHC protons in solid matter will be significantly increased due to hydrodynamic tunneling. For example, in solid copper and solid carbon, these protons and the shower can penetrate up to 35 m and 25 m, respectively. However, their corresponding static range in the two materials is 1 m and 3 m, respectively. This will have important implications on machine protection design. In order to validate these simulation results, experiments have been performed at the CERN HiRadMat facility using the 440 GeV SPS proton beam irradiating solid copper cylindrical target. The phenomenon of hydrodynamic tunneling has been experimentally confirmed and good agreement has been found between the simulations and the experimental results. A very interesting outcome of this work is that the HiRadMat facility can be used to generate High Energy Density matter including Warm Dense Matter and strongly coupled plasmas in the laboratory.

  15. Comprehensive Parameterization of the p-Meson Spectral Function in Hot and Dense Matter

    NASA Astrophysics Data System (ADS)

    Onyango, Thomas; Rapp, Ralf

    2017-09-01

    The goal of this research is to study how hadronic matter transitions into quark-gluon plasma. This transition is believed to have occurred in the early universe about 10 microseconds after the big bang. In particular, this transition created more than 95% of the visible mass in the universe, and confined quarks and gluons into hadrons. Hot nuclear matter can be recreated in the laboratory by colliding heavy atomic nuclei at very high energies. This transition into the quark-gluon plasma can be probed by analyzing the invariant mass distributions of ρ-mesons. The ρ-meson was chosen because it decays into dilepton pairs, e.g. or . Dilepton pairs are a preferred observable because they do not interact through the strong nuclear force inside the strongly interacting fireball, therefore ρ-mesons decay into dileptons in the medium and can be measured during heavy ion collisions. In this project, we developed a parameterization of this process which will help to describe quark-gluon plasma which filled the early universe.

  16. REJECTING PROPOSED DENSE MATTER EQUATIONS OF STATE WITH QUIESCENT LOW-MASS X-RAY BINARIES

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Guillot, Sebastien; Rutledge, Robert E., E-mail: guillots@physics.mcgill.ca, E-mail: rutledge@physics.mcgill.ca

    2014-11-20

    Neutrons stars are unique laboratories for discriminating between the various proposed equations of state of matter at and above nuclear density. One sub-class of neutron stars—those inside quiescent low-mass X-ray binaries (qLMXBs)—produce a thermal surface emission from which the neutron star radius (R {sub NS}) can be measured, using the widely accepted observational scenario for qLMXBs, assuming unmagnetized H atmospheres. In a combined spectral analysis, this work first reproduces a previously published measurement of the R {sub NS}, assumed to be the same for all neutron stars, using a slightly expanded data set. The radius measured is R{sub NS}=9.4±1.2 km.more » On the basis of spectral analysis alone, this measured value is not affected by imposing an assumption of causality in the core. However, the assumptions underlying this R {sub NS} measurement would be falsified by the observation of any neutron star with a mass >2.6 M {sub ☉}, since radii <11 km would be rejected if causality is assumed, which would exclude most of the R {sub NS} parameter space obtained in this analysis. Finally, this work directly tests a selection of dense matter equations of state: WFF1, AP4, MPA1, PAL1, MS0, and three versions of equations of state produced through chiral effective theory. Two of those, MS0 and PAL1, are rejected at the 99% confidence level, accounting for all quantifiable uncertainties, while the other cannot be excluded at >99% certainty.« less

  17. Transverse momentum dependence of spectra of cumulative particles produced from droplets of dense nuclear matter

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Vechernin, Vladimir

    2016-01-22

    The transverse momentum dependence of the yields of particles produced from the clusters of dense cold nuclear matter in nuclei is calculated in the approach based on perturbative QCD calculations of the corresponding quark diagrams near the thresholds. It is shown that the transverse momentum dependence of the pion and proton spectra at different values of the Feynman variable x in the cumulative region, x > 1, can be described by the only parameter - the constituent quark mass, taken to be equal 300 MeV. It is found that the cumulative protons are formed predominantly via a coherent coalescence of threemore » fast cluster quarks, whereas the production of cumulative pions is dominated by one fast cluster quark hadronization. This enabled to explain the experimentally observed more slow increase of the mean transverse momentum of cumulative protons with the increase of the cumulative variable x, compared to pions.« less

  18. Multi-charge-state molecular dynamics and self-diffusion coefficient in the warm dense matter regime

    NASA Astrophysics Data System (ADS)

    Fu, Yongsheng; Hou, Yong; Kang, Dongdong; Gao, Cheng; Jin, Fengtao; Yuan, Jianmin

    2018-01-01

    We present a multi-ion molecular dynamics (MIMD) simulation and apply it to calculating the self-diffusion coefficients of ions with different charge-states in the warm dense matter (WDM) regime. First, the method is used for the self-consistent calculation of electron structures of different charge-state ions in the ion sphere, with the ion-sphere radii being determined by the plasma density and the ion charges. The ionic fraction is then obtained by solving the Saha equation, taking account of interactions among different charge-state ions in the system, and ion-ion pair potentials are computed using the modified Gordon-Kim method in the framework of temperature-dependent density functional theory on the basis of the electron structures. Finally, MIMD is used to calculate ionic self-diffusion coefficients from the velocity correlation function according to the Green-Kubo relation. A comparison with the results of the average-atom model shows that different statistical processes will influence the ionic diffusion coefficient in the WDM regime.

  19. Direct observation of turbulent magnetic fields in hot, dense laser produced plasmas

    PubMed Central

    Mondal, Sudipta; Narayanan, V.; Ding, Wen Jun; Lad, Amit D.; Hao, Biao; Ahmad, Saima; Wang, Wei Min; Sheng, Zheng Ming; Sengupta, Sudip; Kaw, Predhiman; Das, Amita; Kumar, G. Ravindra

    2012-01-01

    Turbulence in fluids is a ubiquitous, fascinating, and complex natural phenomenon that is not yet fully understood. Unraveling turbulence in high density, high temperature plasmas is an even bigger challenge because of the importance of electromagnetic forces and the typically violent environments. Fascinating and novel behavior of hot dense matter has so far been only indirectly inferred because of the enormous difficulties of making observations on such matter. Here, we present direct evidence of turbulence in giant magnetic fields created in an overdense, hot plasma by relativistic intensity (1018W/cm2) femtosecond laser pulses. We have obtained magneto-optic polarigrams at femtosecond time intervals, simultaneously with micrometer spatial resolution. The spatial profiles of the magnetic field show randomness and their k spectra exhibit a power law along with certain well defined peaks at scales shorter than skin depth. Detailed two-dimensional particle-in-cell simulations delineate the underlying interaction between forward currents of relativistic energy “hot” electrons created by the laser pulse and “cold” return currents of thermal electrons induced in the target. Our results are not only fundamentally interesting but should also arouse interest on the role of magnetic turbulence induced resistivity in the context of fast ignition of laser fusion, and the possibility of experimentally simulating such structures with respect to the sun and other stellar environments. PMID:22566660

  20. Direct observation of turbulent magnetic fields in hot, dense laser produced plasmas.

    PubMed

    Mondal, Sudipta; Narayanan, V; Ding, Wen Jun; Lad, Amit D; Hao, Biao; Ahmad, Saima; Wang, Wei Min; Sheng, Zheng Ming; Sengupta, Sudip; Kaw, Predhiman; Das, Amita; Kumar, G Ravindra

    2012-05-22

    Turbulence in fluids is a ubiquitous, fascinating, and complex natural phenomenon that is not yet fully understood. Unraveling turbulence in high density, high temperature plasmas is an even bigger challenge because of the importance of electromagnetic forces and the typically violent environments. Fascinating and novel behavior of hot dense matter has so far been only indirectly inferred because of the enormous difficulties of making observations on such matter. Here, we present direct evidence of turbulence in giant magnetic fields created in an overdense, hot plasma by relativistic intensity (10(18) W/cm(2)) femtosecond laser pulses. We have obtained magneto-optic polarigrams at femtosecond time intervals, simultaneously with micrometer spatial resolution. The spatial profiles of the magnetic field show randomness and their k spectra exhibit a power law along with certain well defined peaks at scales shorter than skin depth. Detailed two-dimensional particle-in-cell simulations delineate the underlying interaction between forward currents of relativistic energy "hot" electrons created by the laser pulse and "cold" return currents of thermal electrons induced in the target. Our results are not only fundamentally interesting but should also arouse interest on the role of magnetic turbulence induced resistivity in the context of fast ignition of laser fusion, and the possibility of experimentally simulating such structures with respect to the sun and other stellar environments.

  1. Interaction of Interstellar Shocks with Dense Obstacles: Formation of ``Bullets''

    NASA Astrophysics Data System (ADS)

    Gvaramadze, V. V.

    The so-called cumulative effect take place in converging conical shock waves arising behind dense obstacles overtaken by incident interstellar shock. A significant part of energy of converging flow of matter swept-up by a radiative conical shock can be transferred to a dense jet-like ejection (``bullet'') directed along the cone axis. Possible applications of this effect for star-forming regions (e.g., OMC-1) and supernova remnants (e.g., Vela SNR) are discussed.

  2. Classical and quantum simulations of warm dense carbon

    NASA Astrophysics Data System (ADS)

    Whitley, Heather; Sanchez, David; Hamel, Sebastien; Correa, Alfredo; Benedict, Lorin

    We have applied classical and DFT-based molecular dynamics (MD) simulations to study the equation of state of carbon in the warm dense matter regime (ρ = 3.7 g/cc, 0.86 eV dense regimes could have important consequences when using classical inter-ionic forces such as these in large-scale MD simulations aimed at studying processes of relevance to inertial confinement fusion. This study points to a need for better interatomic potentials to describe warm dense matter. Prepared by LLNL under Contract DE-AC52-07NA27344.

  3. Hot super-dense compact object with particular EoS

    NASA Astrophysics Data System (ADS)

    Tito, E. P.; Pavlov, V. I.

    2018-03-01

    We show the possibility of existence of a self-gravitating spherically-symmetric equilibrium configuration for a neutral matter with neutron-like density, small mass M ≪ M_{⊙}, and small radius R ≪ R_{⊙}. We incorporate the effects of both the special and general theories of relativity. Such object may be formed in a cosmic cataclysm, perhaps an exotic one. Since the base equations of hydrostatic equilibrium are completed by the equation of state (EoS) for the matter of the object, we offer a novel, interpolating experimental data from high-energy physics, EoS which permits the existence of such compact system of finite radius. This EoS model possesses a critical state characterized by density ρc and temperature Tc. For such an object, we derive a radial distribution for the super-dense matter in "liquid" phase using Tolman-Oppenheimer-Volkoff equations for hydrostatic equilibrium. We demonstrate that a stable configuration is indeed possible (only) for temperatures smaller than the critical one. We derive the mass-radius relation (adjusted for relativistic corrections) for such small (M ≪ M_{⊙}) super-dense compact objects. The results are within the constraints established by both heavy-ion collision experiments and theoretical studies of neutron-rich matter.

  4. Ion-ion dynamic structure factor of warm dense mixtures

    DOE PAGES

    Gill, N. M.; Heinonen, R. A.; Starrett, C. E.; ...

    2015-06-25

    In this study, the ion-ion dynamic structure factor of warm dense matter is determined using the recently developed pseudoatom molecular dynamics method [Starrett et al., Phys. Rev. E 91, 013104 (2015)]. The method uses density functional theory to determine ion-ion pair interaction potentials that have no free parameters. These potentials are used in classical molecular dynamics simulations. This constitutes a computationally efficient and realistic model of dense plasmas. Comparison with recently published simulations of the ion-ion dynamic structure factor and sound speed of warm dense aluminum finds good to reasonable agreement. Using this method, we make predictions of the ion-ionmore » dynamical structure factor and sound speed of a warm dense mixture—equimolar carbon-hydrogen. This material is commonly used as an ablator in inertial confinement fusion capsules, and our results are amenable to direct experimental measurement.« less

  5. Rapid heating of matter using high power lasers

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bang, Woosuk

    2016-04-08

    This slide presentation describes motivation (uniform and rapid heating of a target, opportunity to study warm dense matter, study of nuclear fusion reactions), rapid heating of matter with intense laser-driven ion beams, visualization of the expanding warm dense gold and diamond, and nuclear fusion experiments using high power lasers (direct heating of deuterium spheres (radius ~ 10nm) with an intense laser pulse.

  6. Multiple shock reverberation compression of dense Ne up to the warm dense regime: Evaluating the theoretical models

    NASA Astrophysics Data System (ADS)

    Tang, J.; Gu, Y. J.; Chen, Q. F.; Li, Z. G.; Zheng, J.; Li, C. J.; Li, J. T.

    2018-04-01

    Multiple shock reverberation compression experiments are designed and performed to determine the equation of state of neon ranging from the initial dense gas up to the warm dense regime where the pressure is from about 40 MPa to 120 GPa and the temperature is from about 297 K up to above 20 000 K. The wide region experimental data are used to evaluate the available theoretical models. It is found that, for neon below 1.1 g/cm 3 , within the framework of density functional theory molecular dynamics, a van der Waals correction is meaningful. Under high pressure and temperature, results from the self-consistent fluid variational theory model are sensitive to the potential parameter and could give successful predictions in the whole experimental regime if a set of proper parameters is employed. The new observations on neon under megabar (1 Mbar =1011Pa ) pressure and eV temperature (1 eV ≈104K ) enrich the understanding on properties of warm dense matter and have potential applications in revealing the formation and evolution of gaseous giants or mega-Earths.

  7. Laboratory study of dense planetary interiors and giant impacts using laser-driven shock waves

    NASA Astrophysics Data System (ADS)

    Hicks, Damien

    2005-10-01

    The behavior of matter at Megabar pressures, a few times solid density, and eV temperatures presents a fundamental challenge, one that is critical to our understanding of dense planetary interiors, planetary evolution models, and giant impacts. Under these conditions bulk matter is strongly coupled, with temperatures approaching the Fermi energy and electron wavelengths comparable to the interatomic spacing - a quantum-classical ``transition'' regime not amenable to many of the traditional theoretical approaches used in condensed matter or plasma physics. The laser-driven shock wave has matured into a powerful tool for accessing and probing these conditions with several new techniques having been developed recently. Measurements of the equation-of-state and transport properties of important planetary materials including silica ( SiO2 ) and hydrogen have been performed. In particular, silica - the major constituent of terrestrial planets - has been shown to undergo an insulator-to-conductor transition above melting at conditions similar to those in giant impacts (such as the one believed to have created the Moon) and at the earth's core-mantle boundary. This continuous transformation, occurring at pressures between 1 to ˜4 Mbar, is accompanied by an anomalously high specific heat that returns to the Dulong-Petit value at completion of the transformation. This is suggestive of a ``bond-breaking'' process in the condensed system - analogous to dissociation in a gas - as the fluid transforms from liquid to dense plasma. Work performed in collaboration with T. R. Boehly, P. M. Celliers, J. H. Eggert, J. E. Miller, D. D. Meyerhofer, and G. W. Collins under the auspices of the US DOE by LLNL under Contract No. W-7405-ENG-48 and by the U. Rochester under Cooperative Agreement No. DE-FC03-92SF19460.

  8. Importance of finite-temperature exchange correlation for warm dense matter calculations.

    PubMed

    Karasiev, Valentin V; Calderín, Lázaro; Trickey, S B

    2016-06-01

    The effects of an explicit temperature dependence in the exchange correlation (XC) free-energy functional upon calculated properties of matter in the warm dense regime are investigated. The comparison is between the Karasiev-Sjostrom-Dufty-Trickey (KSDT) finite-temperature local-density approximation (TLDA) XC functional [Karasiev et al., Phys. Rev. Lett. 112, 076403 (2014)PRLTAO0031-900710.1103/PhysRevLett.112.076403] parametrized from restricted path-integral Monte Carlo data on the homogeneous electron gas (HEG) and the conventional Monte Carlo parametrization ground-state LDA XC [Perdew-Zunger (PZ)] functional evaluated with T-dependent densities. Both Kohn-Sham (KS) and orbital-free density-functional theories are used, depending upon computational resource demands. Compared to the PZ functional, the KSDT functional generally lowers the dc electrical conductivity of low-density Al, yielding improved agreement with experiment. The greatest lowering is about 15% for T=15 kK. Correspondingly, the KS band structure of low-density fcc Al from the KSDT functional exhibits a clear increase in interband separation above the Fermi level compared to the PZ bands. In some density-temperature regimes, the deuterium equations of state obtained from the two XC functionals exhibit pressure differences as large as 4% and a 6% range of differences. However, the hydrogen principal Hugoniot is insensitive to the explicit XC T dependence because of cancellation between the energy and pressure-volume work difference terms in the Rankine-Hugoniot equation. Finally, the temperature at which the HEG becomes unstable is T≥7200 K for the T-dependent XC, a result that the ground-state XC underestimates by about 1000 K.

  9. Concluding Remarks: Connecting Relativistic Heavy Ion Collisions and Neutron Star Mergers by the Equation of State of Dense Hadron- and Quark Matter as signalled by Gravitational Waves

    NASA Astrophysics Data System (ADS)

    Hanauske, Matthias; Steinheimer, Jan; Bovard, Luke; Mukherjee, Ayon; Schramm, Stefan; Takami, Kentaro; Papenfort, Jens; Wechselberger, Natascha; Rezzolla, Luciano; Stöcker, Horst

    2017-07-01

    The underlying open questions in the fields of general relativistic astrophysics and elementary particle and nuclear physics are strongly connected and their results are interdependent. Although the physical systems are quite different, the 4D-simulation of a merger of a binary system of two neutron stars and the properties of the hot and dense matter created in high energy heavy ion collisions, strongly depend on the equation of state of fundamental elementary matter. Neutron star mergers represent optimal astrophysical laboratories to investigate the QCD phase structure using a spectrogram of the post-merger phase of the emitted gravitational waves. These studies can be supplemented by observations from heavy ion collisions to possibly reach a conclusive picture on the QCD phase structure at high density and temperature. As gravitational waves (GWs) emitted from merging neutron star binaries are on the verge of their first detection, it is important to understand the main characteristics of the underlying merging system in order to predict the expected GW signal. Based on numerical-relativity simulations of merging neutron star binaries, the emitted GW and the interior structure of the generated hypermassive neutron stars (HMNS) have been analyzed in detail. This article will focus on the internal and rotational HMNS properties and their connection with the emitted GW signal. Especially, the appearance of the hadon-quark phase transition in the interior region of the HMNS and its conjunction with the spectral properties of the emitted GW will be addressed and confronted with the simulation results of high energy heavy ion collisions.

  10. First-Principles Estimation of Electronic Temperature from X-Ray Thomson Scattering Spectrum of Isochorically Heated Warm Dense Matter

    NASA Astrophysics Data System (ADS)

    Mo, Chongjie; Fu, Zhenguo; Kang, Wei; Zhang, Ping; He, X. T.

    2018-05-01

    Through the perturbation formula of time-dependent density functional theory broadly employed in the calculation of solids, we provide a first-principles calculation of x-ray Thomson scattering spectrum of isochorically heated aluminum foil, as considered in the experiments of Sperling et al. [Phys. Rev. Lett. 115, 115001 (2015), 10.1103/PhysRevLett.115.115001], where ions were constrained near their lattice positions. From the calculated spectra, we find that the electronic temperature cannot exceed 2 eV, much smaller than the previous estimation of 6 eV via the detailed balance relation. Our results may well be an indication of unique electronic properties of warm dense matter, which can be further illustrated by future experiments. The lower electronic temperature predicted partially relieves the concern on the heating of x-ray free electron laser to the sample when used in structure measurement.

  11. Coalescence preference in dense packing of bubbles

    NASA Astrophysics Data System (ADS)

    Kim, Yeseul; Gim, Bopil; Gim, Bopil; Weon, Byung Mook

    2015-11-01

    Coalescence preference is the tendency that a merged bubble from the contact of two original bubbles (parent) tends to be near to the bigger parent. Here, we show that the coalescence preference can be blocked by densely packing of neighbor bubbles. We use high-speed high-resolution X-ray microscopy to clearly visualize individual coalescence phenomenon which occurs in micro scale seconds and inside dense packing of microbubbles with a local packing fraction of ~40%. Previous theory and experimental evidence predict a power of -5 between the relative coalescence position and the parent size. However, our new observation for coalescence preference in densely packed microbubbles shows a different power of -2. We believe that this result may be important to understand coalescence dynamics in dense packing of soft matter. This work (NRF-2013R1A22A04008115) was supported by Mid-career Researcher Program through NRF grant funded by the MEST and also was supported by Ministry of Science, ICT and Future Planning (2009-0082580) and by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry and Education, Science and Technology (NRF-2012R1A6A3A04039257).

  12. Influence of galactic arm scale dynamics on the molecular composition of the cold and dense ISM. I. Observed abundance gradients in dense clouds

    NASA Astrophysics Data System (ADS)

    Ruaud, M.; Wakelam, V.; Gratier, P.; Bonnell, I. A.

    2018-04-01

    Aim. We study the effect of large scale dynamics on the molecular composition of the dense interstellar medium during the transition between diffuse to dense clouds. Methods: We followed the formation of dense clouds (on sub-parsec scales) through the dynamics of the interstellar medium at galactic scales. We used results from smoothed particle hydrodynamics (SPH) simulations from which we extracted physical parameters that are used as inputs for our full gas-grain chemical model. In these simulations, the evolution of the interstellar matter is followed for 50 Myr. The warm low-density interstellar medium gas flows into spiral arms where orbit crowding produces the shock formation of dense clouds, which are held together temporarily by the external pressure. Results: We show that depending on the physical history of each SPH particle, the molecular composition of the modeled dense clouds presents a high dispersion in the computed abundances even if the local physical properties are similar. We find that carbon chains are the most affected species and show that these differences are directly connected to differences in (1) the electronic fraction, (2) the C/O ratio, and (3) the local physical conditions. We argue that differences in the dynamical evolution of the gas that formed dense clouds could account for the molecular diversity observed between and within these clouds. Conclusions: This study shows the importance of past physical conditions in establishing the chemical composition of the dense medium.

  13. Dense matter at RHIC: Anisotropic flow

    DOE PAGES

    Voloshin, S. A.

    2005-02-01

    In this talk I discuss recent results on elliptic flow in Au+Au collisions at RHIC and how these results help us to understand the properties and evolution dynamics of the system created in such collisions. In particular, I discuss if and how the elliptic flow results obtained at RHIC indicate the system thermalization, deconfinement, and how much it tells us about the hadronization process.

  14. Electrical conductivity calculations in isochorically heated warm dense aluminum

    NASA Astrophysics Data System (ADS)

    Sperling, P.; Rosmej, S.; Bredow, R.; Fletcher, L. B.; Galtier, E.; Gamboa, E. J.; Lee, H. J.; Reinholz, H.; Röpke, G.; Zastrau, U.; Glenzer, S. H.

    2017-07-01

    We present a theoretical approach to derive the dc conductivity of warm dense matter (WDM) from x-ray Thomson scattering data. Predictions for the conductivity of aluminum at condensed matter densities are given within a wide temperature range (0.08 {eV}< {k}{{B}}T< 80 eV). Strong correlation effects are taken into account by ionic structure factors. Screening and Pauli blocking are described via a pseudopotential. The results are compared with other theoretical models and simulations as well as with experimental measurements in the liquid metal regime and recent experiments in the WDM regime.

  15. Observations of non-linear plasmon damping in dense plasmas

    NASA Astrophysics Data System (ADS)

    Witte, B. B. L.; Sperling, P.; French, M.; Recoules, V.; Glenzer, S. H.; Redmer, R.

    2018-05-01

    We present simulations using finite-temperature density-functional-theory molecular-dynamics to calculate dynamic dielectric properties in warm dense aluminum. The comparison between exchange-correlation functionals in the Perdew, Burke, Ernzerhof approximation, Strongly Constrained and Appropriately Normed Semilocal Density Functional, and Heyd, Scuseria, Ernzerhof (HSE) approximation indicates evident differences in the electron transition energies, dc conductivity, and Lorenz number. The HSE calculations show excellent agreement with x-ray scattering data [Witte et al., Phys. Rev. Lett. 118, 225001 (2017)] as well as dc conductivity and absorption measurements. These findings demonstrate non-Drude behavior of the dynamic conductivity above the Cooper minimum that needs to be taken into account to determine optical properties in the warm dense matter regime.

  16. The dark matter of galaxy voids

    NASA Astrophysics Data System (ADS)

    Sutter, P. M.; Lavaux, Guilhem; Wandelt, Benjamin D.; Weinberg, David H.; Warren, Michael S.

    2014-03-01

    How do observed voids relate to the underlying dark matter distribution? To examine the spatial distribution of dark matter contained within voids identified in galaxy surveys, we apply Halo Occupation Distribution models representing sparsely and densely sampled galaxy surveys to a high-resolution N-body simulation. We compare these galaxy voids to voids found in the halo distribution, low-resolution dark matter and high-resolution dark matter. We find that voids at all scales in densely sampled surveys - and medium- to large-scale voids in sparse surveys - trace the same underdensities as dark matter, but they are larger in radius by ˜20 per cent, they have somewhat shallower density profiles and they have centres offset by ˜ 0.4Rv rms. However, in void-to-void comparison we find that shape estimators are less robust to sampling, and the largest voids in sparsely sampled surveys suffer fragmentation at their edges. We find that voids in galaxy surveys always correspond to underdensities in the dark matter, though the centres may be offset. When this offset is taken into account, we recover almost identical radial density profiles between galaxies and dark matter. All mock catalogues used in this work are available at http://www.cosmicvoids.net.

  17. Development and testing of a pulsed helium ion source for probing materials and warm dense matter studies

    NASA Astrophysics Data System (ADS)

    Ji, Q.; Seidl, P. A.; Waldron, W. L.; Takakuwa, J. H.; Friedman, A.; Grote, D. P.; Persaud, A.; Barnard, J. J.; Schenkel, T.

    2016-02-01

    The neutralized drift compression experiment was designed and commissioned as a pulsed, linear induction accelerator to drive thin targets to warm dense matter (WDM) states with peak temperatures of ˜1 eV using intense, short pulses (˜1 ns) of 1.2 MeV lithium ions. At that kinetic energy, heating a thin target foil near the Bragg peak energy using He+ ions leads to more uniform energy deposition of the target material than Li+ ions. Experiments show that a higher current density of helium ions can be delivered from a plasma source compared to Li+ ions from a hot plate type ion source. He+ beam pulses as high as 200 mA at the peak and 4 μs long were measured from a multi-aperture 7-cm-diameter emission area. Within ±5% variation, the uniform beam area is approximately 6 cm across. The accelerated and compressed pulsed ion beams can be used for materials studies and isochoric heating of target materials for high energy density physics experiments and WDM studies.

  18. Development and testing of a pulsed helium ion source for probing materials and warm dense matter studies.

    PubMed

    Ji, Q; Seidl, P A; Waldron, W L; Takakuwa, J H; Friedman, A; Grote, D P; Persaud, A; Barnard, J J; Schenkel, T

    2016-02-01

    The neutralized drift compression experiment was designed and commissioned as a pulsed, linear induction accelerator to drive thin targets to warm dense matter (WDM) states with peak temperatures of ∼1 eV using intense, short pulses (∼1 ns) of 1.2 MeV lithium ions. At that kinetic energy, heating a thin target foil near the Bragg peak energy using He(+) ions leads to more uniform energy deposition of the target material than Li(+) ions. Experiments show that a higher current density of helium ions can be delivered from a plasma source compared to Li(+) ions from a hot plate type ion source. He(+) beam pulses as high as 200 mA at the peak and 4 μs long were measured from a multi-aperture 7-cm-diameter emission area. Within ±5% variation, the uniform beam area is approximately 6 cm across. The accelerated and compressed pulsed ion beams can be used for materials studies and isochoric heating of target materials for high energy density physics experiments and WDM studies.

  19. Development and testing of a pulsed helium ion source for probing materials and warm dense matter studies

    DOE PAGES

    Ji, Q.; Seidl, P. A.; Waldron, W. L.; ...

    2015-11-12

    In this paper, the neutralized drift compression experiment was designed and commissioned as a pulsed, linear induction accelerator to drive thin targets to warm dense matter (WDM) states with peak temperatures of ~1 eV using intense, short pulses (~1 ns) of 1.2 MeV lithium ions. At that kinetic energy, heating a thin target foil near the Bragg peak energy using He + ions leads to more uniform energy deposition of the target material than Li + ions. Experiments show that a higher current density of helium ions can be delivered from a plasma source compared to Li + ions frommore » a hot plate type ion source. He + beam pulses as high as 200 mA at the peak and 4 μs long were measured from a multi-aperture 7-cm-diameter emission area. Within ±5% variation, the uniform beam area is approximately 6 cm across. Finally, the accelerated and compressed pulsed ion beams can be used for materials studies and isochoric heating of target materials for high energy density physics experiments and WDM studies.« less

  20. X-Ray Emission from Supernovae in Dense Circumstellar Matter Environments: A Search for Collisionless Shock

    NASA Technical Reports Server (NTRS)

    Ofek, E.O; Fox, D.; Cenko, B.; Sullivan, M.; Gnat, O.; Frail A.; Horesh, A.; Corsi, A; Quimby, R. M.; Gehrels, N.; hide

    2012-01-01

    The optical light curve of some supernovae (SNe) may be powered by the outward diffusion of the energy deposited by the explosion shock (so-called shock breakout) in optically thick (tau approx > 30) circumstellar matter (CSM). Recently, it was shown that the radiation-mediated and -dominated shock in an optically thick wind must transform into 8. collisionless shock and can produce hard X-rays. The X-rays are expected to peak at late times, relative to maximum visible light. Here we report on a search, using Swift-XRT and Chandra, for X-ray emission from 28 SNe that belong to classes whose progenitors are suspected to be embedded in dense CSM. Our sample includes 19 type-IIn SNe, one type-Ibn SN and eiht hydrogen-poor super-luminous SNe (SLSN-I; SN 2005ap like). Two SNe (SN 2006jc and SN 2010jl) have X-ray properties that are roughly consistent with the expectation for X-rays from a collisionless shock in optically thick CSl\\l. Therefore, we suggest that their optical light curves are powered by shock breakout in CSM. We show that two other events (SN 2010al and SN 2011ht) were too X-ray bright during the SN maximum optical light to be explained by the shock breakout model. We conclude that the light curves of some, but not all, type-IIn/Ibn SNe are powered by shock breakout in CSM. For the rest of the SNe in our sample, including all the SLSN-I events, our X-ray limits are not deep enough and were typically obtained at too early times (i.e., near the SN maximum light) to conclude about their nature. Late time X-ray observations are required in order to further test if these SNe are indeed embedded in dense CSM. We review the conditions required for a shock breakOut in a wind profile. We argue that the time scale, relative to maximum light, for the SN to peak in X-rays is a probe of the column density and the density profile above the shock region. The optical light curves of SNe, for which the X-ray emission peaks at late times, are likely powered by the

  1. Quantum molecular dynamics study on the structures and dc conductivity of warm dense silane

    NASA Astrophysics Data System (ADS)

    Sun, Huayang; Kang, Dongdong; Dai, Jiayu; Zeng, Jiaolong; Yuan, Jianmin

    2014-02-01

    The ionic and electronic structures of warm dense silane at the densities of 1.795, 2.260, 3.382, and 3.844 g/cm3 have been studied with temperatures from 1000 K to 3 eV using quantum molecular dynamics simulations. At all densities, the structures are melted above 1000 K. The matter states are characterized as polymeric from 1000 to 4000 K and become dense plasma states with further increasing temperature to 1 eV. At two lower densities of 1.795 and 2.260 g/cm3, silane first dissociates and then becomes the polymeric state via a chain state from the initial crystalline structure. At higher densities, however, no dissociation stage was found. These findings can help us understand how the warm dense matter forms. A rise is found for the direct current electric conductivity at T ˜1000 K, indicating the nonmetal-to-metal transition. The conductivity decreases slightly with the increase of temperature, which is due to the more disordered structures at higher temperatures.

  2. Quark matter droplets in neutron stars

    NASA Technical Reports Server (NTRS)

    Heiselberg, H.; Pethick, C. J.; Staubo, E. F.

    1993-01-01

    We show that, for physically reasonable bulk and surface properties, the lowest energy state of dense matter consists of quark matter coexisting with nuclear matter in the presence of an essentially uniform background of electrons. We estimate the size and nature of spatial structure in this phase, and show that at the lowest densities the quark matter forms droplets embedded in nuclear matter, whereas at higher densities it can exhibit a variety of different topologies. A finite fraction of the interior of neutron stars could consist of matter in this new phase, which would provide new mechanisms for glitches and cooling.

  3. Kinetic Modeling of Ultraintense X-ray Laser-Matter Interactions

    NASA Astrophysics Data System (ADS)

    Royle, Ryan; Sentoku, Yasuhiko; Mancini, Roberto

    2016-10-01

    Hard x-ray free-electron lasers (XFELs) have had a profound impact on the physical, chemical, and biological sciences. They can produce millijoule x-ray laser pulses just tens of femtoseconds in duration with more than 1012 photons each, making them the brightest laboratory x-ray sources ever produced by several orders of magnitude. An XFEL pulse can be intensified to 1020 W/cm2 when focused to submicron spot sizes, making it possible to isochorically heat solid matter well beyond 100 eV. These characteristics enable XFELs to create and probe well-characterized warm and hot dense plasmas of relevance to HED science, planetary science, laboratory astrophysics, relativistic laser plasmas, and fusion research. Several newly developed atomic physics models including photoionization, Auger ionization, and continuum-lowering have been implemented in a particle-in-cell code, PICLS, which self-consistently solves the x-ray transport, to enable the simulation of the non-LTE plasmas created by ultraintense x-ray laser interactions with solid density matter. The code is validated against the results of several recent experiments and is used to simulate the maximum-intensity x-ray heating of solid iron targets. This work was supported by DOE/OFES under Contract No. DE-SC0008827.

  4. SPiRIT-TPC with GET readout electronics for the study of density dependent symmetry energy of high dense matter with Heavy RI collisions

    NASA Astrophysics Data System (ADS)

    Isobe, Tadaaki; SPiRIT Collaboration

    2014-09-01

    The nuclear Equation of State (EoS) is a fundamental property of nuclear matter that describes the relationships between the parameters for a nuclear system, such as energy, density and temperature. An international collaboration, named SPiRIT, to study the nuclear EoS has been formed recently. One of the main devices of experimental setup is a Time Projection Chamber (TPC) which will be installed into the SAMURAI dipole magnet at RIKEN-RIBF. The TPC can measure charged pions, protons and light ions simultaneously in heavy RI collisions, and those will be used as probes to study the asymmetric dense nuclear matter. In addition to the status of the SPiRIT project, testing of SPiRIT-TPC with GET electronics will be presented in this talk. GET, general electronics for TPC, is a project for the development of novel electronics for TPC supported by NSF and ANR. This work is supported in part by the Japan Grant-in-Aide award and the US DOE grant DE-SC0004835 and JUSEIPEN.

  5. Equilibrium nuclear ensembles taking into account vaporization of hot nuclei in dense stellar matter

    NASA Astrophysics Data System (ADS)

    Furusawa, Shun; Mishustin, Igor

    2018-02-01

    We investigate the high-temperature effect on the nuclear matter that consists of mixture of nucleons and all nuclei in the dense and hot stellar environment. The individual nuclei are described within the compressible-liquid-drop model that is based on Skyrme interactions for bulk energies and that takes into account modifications of the surface and Coulomb energies at finite temperatures and densities. The free-energy density is minimized with respect to the individual equilibrium densities of all heavy nuclei and the nuclear composition. We find that their optimized equilibrium densities become smaller and smaller at high temperatures because of the increase in thermal contributions to bulk free energies and the reduction of surface energies. The neutron-rich nuclei become unstable and disappear one after another at given temperatures. The calculations are performed for two sets of model parameters leading to different values of the slope parameter in the nuclear-symmetry energy. It is found that the larger slope parameter reduces the equilibrium densities and the melting temperatures. We also compare the proposed model with some other approaches and find that the mass fractions of heavy nuclei in the previous calculations that omit vaporization are underestimated at T ≲10 MeV and overestimated at T ≳10 MeV. The further sophistication of calculations of nuclear vaporization and of light clusters would be required to construct the equation of state for explosive astrophysical phenomena.

  6. A high-speed tracking algorithm for dense granular media

    NASA Astrophysics Data System (ADS)

    Cerda, Mauricio; Navarro, Cristóbal A.; Silva, Juan; Waitukaitis, Scott R.; Mujica, Nicolás; Hitschfeld, Nancy

    2018-06-01

    Many fields of study, including medical imaging, granular physics, colloidal physics, and active matter, require the precise identification and tracking of particle-like objects in images. While many algorithms exist to track particles in diffuse conditions, these often perform poorly when particles are densely packed together-as in, for example, solid-like systems of granular materials. Incorrect particle identification can have significant effects on the calculation of physical quantities, which makes the development of more precise and faster tracking algorithms a worthwhile endeavor. In this work, we present a new tracking algorithm to identify particles in dense systems that is both highly accurate and fast. We demonstrate the efficacy of our approach by analyzing images of dense, solid-state granular media, where we achieve an identification error of 5% in the worst evaluated cases. Going further, we propose a parallelization strategy for our algorithm using a GPU, which results in a speedup of up to 10 × when compared to a sequential CPU implementation in C and up to 40 × when compared to the reference MATLAB library widely used for particle tracking. Our results extend the capabilities of state-of-the-art particle tracking methods by allowing fast, high-fidelity detection in dense media at high resolutions.

  7. Dense crystalline packings of ellipsoids

    NASA Astrophysics Data System (ADS)

    Jin, Weiwei; Jiao, Yang; Liu, Lufeng; Yuan, Ye; Li, Shuixiang

    2017-03-01

    An ellipsoid, the simplest nonspherical shape, has been extensively used as a model for elongated building blocks for a wide spectrum of molecular, colloidal, and granular systems. Yet the densest packing of congruent hard ellipsoids, which is intimately related to the high-density phase of many condensed matter systems, is still an open problem. We discover an unusual family of dense crystalline packings of self-dual ellipsoids (ratios of the semiaxes α : √{α }:1 ), containing 24 particles with a quasi-square-triangular (SQ-TR) tiling arrangement in the fundamental cell. The associated packing density ϕ exceeds that of the densest known SM2 crystal [ A. Donev et al., Phys. Rev. Lett. 92, 255506 (2004), 10.1103/PhysRevLett.92.255506] for aspect ratios α in (1.365, 1.5625), attaining a maximal ϕ ≈0.758 06 ... at α = 93 /64 . We show that the SQ-TR phase derived from these dense packings is thermodynamically stable at high densities over the aforementioned α range and report a phase diagram for self-dual ellipsoids. The discovery of the SQ-TR crystal suggests organizing principles for nonspherical particles and self-assembly of colloidal systems.

  8. Kinetic Modeling of Ultraintense X-Ray Laser-Matter Interactions

    NASA Astrophysics Data System (ADS)

    Royle, Ryan; Sentoku, Yasuhiko; Mancini, Roberto; Johzaki, Tomoyuki

    2015-11-01

    High-intensity XFELs have become a novel way of creating and studying hot dense plasmas. The LCLS at Stanford can deliver a millijoule of energy with more than 1012 photons in a ~ 100 femtosecond pulse. By tightly focusing the beam to a micron-scale spot size, the XFEL can be intensified to more than 1018 W/cm2, making it possible to heat solid matter isochorically beyond a million degrees (>100 eV). Such extreme states of matter are of considerable interest due to their relevance to astrophysical plasmas. Additionally, they will allow novel ways of studying equation-of-state and opacity physics under Gbar pressure and strong fields. Photoionization is the dominant x-ray absorption mechanism and triggers the heating processes. A photoionization model that takes into account the subshell cross-sections has been developed in a kinetic plasma simulation code, PICLS, that solves the x-ray transport self-consistently. The XFEL-matter interaction with several elements, including solid carbon, aluminum, and iron, is studied with the code, and the results are compared with recent LCLS experiments. This work was supported by the DOE/OFES under Contract No. DE-SC0008827.

  9. X-ray Thomson scattering measurement of temperature in warm dense carbon

    DOE PAGES

    Falk, Katerina; Fryer, C. L.; Gamboa, E. J.; ...

    2016-11-22

    Here, a novel platform to measure the equation of state using a combination of diagnostics, where the spectrally resolved x-ray Thomson scattering (XRTS) is used to obtain accurate temperature measurements of warm dense matter (WDM) was developed for the OMEGA laser facility. OMEGA laser beams have been used to drive strong shocks in carbon targets creating WDM and generating the Ni He-alpha x-ray probe used for XRTS. Additional diagnostics including x-ray radiography, velocity interferometry and streaked optical pyrometry provided complementary measurements of density and pressure. The WDM regime of near solid density and moderate temperatures (1–100 eV) is a challengingmore » yet important area of research in inertial confinement fusion and astrophysics. This platform has been used to study off-Hugoniot states of shock-released diamond and graphite at pressures between 1 and 10 Mbar and temperatures between 5 and 15 eV as well as first x-ray Thomson scattering data from shocked low density CH foams reaching five times compression and temperatures of 20–30 eV.« less

  10. New color-magnetic defects in dense quark matter

    NASA Astrophysics Data System (ADS)

    Haber, Alexander; Schmitt, Andreas

    2018-06-01

    Color-flavor locked (CFL) quark matter expels color-magnetic fields due to the Meissner effect. One of these fields carries an admixture of the ordinary abelian magnetic field and therefore flux tubes may form if CFL matter is exposed to a magnetic field, possibly in the interior of neutron stars or in quark stars. We employ a Ginzburg–Landau approach for three massless quark flavors, which takes into account the multi-component nature of color superconductivity. Based on the weak-coupling expressions for the Ginzburg–Landau parameters, we identify the regime where CFL is a type-II color superconductor and compute the radial profiles of different color-magnetic flux tubes. Among the configurations without baryon circulation we find a new solution that is energetically preferred over the flux tubes previously discussed in the literature in the parameter regime relevant for compact stars. Within the same setup, we also find a new defect in the 2SC phase, namely magnetic domain walls, which emerge naturally from the previously studied flux tubes if a more general ansatz for the order parameter is used. Color-magnetic defects in the interior of compact stars allow for sustained deformations of the star, potentially strong enough to produce detectable gravitational waves.

  11. X-ray Emission from Supernovae in Dense Circumstellar Matter Environments: a Search for Collisionless Shocks

    NASA Technical Reports Server (NTRS)

    Ofek, E. O.; Fox, D.; Cenko, Stephen B.; Sullivan, M; Gnat, O.; Frail, D. A.; Horesh, A.; Corsi, A.; Quimby, R. M.; Gehrels, N.; hide

    2013-01-01

    The optical light curve of some supernovae (SNe) may be powered by the outward diffusion of the energy deposited by the explosion shock (the so-called shock breakout) in optically thick (Tau approx > 30) circumstellar matter (CSM). Recently, it was shown that the radiation-mediated and radiation-dominated shock in an optically thick wind must transform into a collisionless shock and can produce hard X-rays. The X-rays are expected to peak at late times, relative to maximum visible light. Here we report on a search, using Swift/XRT and Chandra, for X-ray emission from 28 SNe that belong to classes whose progenitors are suspected to be embedded in dense CSM. Our sample includes 19 Type IIn SNe, one Type Ibn SN, and eight hydrogen-poor superluminous SNe (SLSN-I such as SN 2005ap). Two SNe (SN 2006jc and SN 2010jl) have X-ray properties that are roughly consistent with the expectation for X-rays from a collisionless shock in optically thick CSM. However, the X-ray emission from SN 2006jc can also be explained as originating in an optically thin region. Thus, we propose that the optical light curve of SN 2010jl is powered by shock breakout in CSM. We suggest that two other events (SN 2010al and SN 2011ht) were too X-ray bright during the SN maximum optical light to be explained by the shock-breakout model.We conclude that the light curves of some, but not all, SNe IIn/Ibn are powered by shock breakout in CSM. For the rest of the SNe in our sample, including all of the SLSN-I events, our X-ray limits are not deep enough and were typically obtained too early (i.e., near the SN maximum light) for definitive conclusions about their nature. Late-time X-ray observations are required in order to further test whether these SNe are indeed embedded in dense CSM. We review the conditions required for a shock breakout in a wind profile. We argue that the timescale, relative to maximum light, for the SN to peak in X-rays is a probe of the column density and the density profile above

  12. Dense water plumes modulate richness and productivity of deep sea microbes.

    PubMed

    Luna, Gian Marco; Chiggiato, Jacopo; Quero, Grazia Marina; Schroeder, Katrin; Bongiorni, Lucia; Kalenitchenko, Dimitri; Galand, Pierre E

    2016-12-01

    Growing evidence indicates that dense water formation and flow over the continental shelf is a globally relevant oceanographic process, potentially affecting microbial assemblages down to the deep ocean. However, the extent and consequences of this influence have yet to be investigated. Here it is shown that dense water propagation to the deep ocean increases the abundance of prokaryotic plankton, and stimulates carbon production and organic matter degradation rates. Dense waters spilling off the shelf modifies community composition of deep sea microbial assemblages, leading to the increased relevance of taxa likely originating from the sea surface and the seafloor. This phenomenon can be explained by a combination of factors that interplay during the dense waters propagation, such as the transport of surface microbes to the ocean floor (delivering in our site 0.1 megatons of C), the stimulation of microbial metabolism due to increased ventilation and nutrients availability, the sediment re-suspension, and the mixing with ambient waters along the path. Thus, these results highlight a hitherto unidentified role for dense currents flowing over continental shelves in influencing deep sea microbes. In light of climate projections, this process will affect significantly the microbial functioning and biogeochemical cycling of large sectors of the ocean interior. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

  13. Pump-probe studies of radiation induced defects and formation of warm dense matter with pulsed ion beams

    NASA Astrophysics Data System (ADS)

    Schenkel, T.; Persaud, A.; Gua, H.; Seidl, P. A.; Waldron, W. L.; Gilson, E. P.; Kaganovich, I. D.; Davidson, R. C.; Friedman, A.; Barnard, J. J.; Minior, A. M.

    2014-10-01

    We report results from the 2nd generation Neutralized Drift Compression Experiment at Berkeley Lab. NDCX-II is a pulsed, linear induction accelerator designed to drive thin foils to warm dense matter (WDM) states with peak temperatures of ~ 1 eV using intense, short pulses of 1.2 MeV lithium ions. Tunability of the ion beam enables pump-probe studies of radiation effects in solids as a function of excitation density, from isolated collision cascades to the onset of phase-transitions and WDM. Ion channeling is an in situ diagnostic of damage evolution during ion pulses with a sensitivity of <0.1% displacements per atom. We will report results from damage evolution studies in thin silicon crystals with Li + and K + beams. Detection of channeled ions tracks lattice disorder evolution with a resolution of ~ 1 ns using fast current measurements. We will discuss pump-probe experiments with pulsed ion beams and the development of diagnostics for WDM and multi-scale (ms to fs) access to the materials physics of collision cascades e.g. in fusion reactor materials. Work performed under auspices of the US DOE under Contract No. DE-AC02-05CH11231.

  14. Lattice Stability and Interatomic Potential of Non-equilibrium Warm Dense Gold

    NASA Astrophysics Data System (ADS)

    Chen, Z.; Mo, M.; Soulard, L.; Recoules, V.; Hering, P.; Tsui, Y. Y.; Ng, A.; Glenzer, S. H.

    2017-10-01

    Interatomic potential is central to the calculation and understanding of the properties of matter. A manifestation of interatomic potential is lattice stability in the solid-liquid transition. Recently, we have used frequency domain interferometry (FDI) to study the disassembly of ultrafast laser heated warm dense gold nanofoils. The FDI measurement is implemented by a spatial chirped single-shot technique. The disassembly of the sample is characterized by the change in phase shift of the reflected probe resulted from hydrodynamic expansion. The experimental data is compared with the results of two-temperature molecular dynamic simulations based on a highly optimized embedded-atom-method (EAM) interatomic potential. Good agreement is found for absorbed energy densities of 0.9 to 4.3MJ/kg. This provides the first demonstration of the applicability of an EAM interatomic potential in the non-equilibrium warm dense matter regime. The MD simulations also reveal the critical role of pressure waves in solid-liquid transition in ultrafast laser heated nanofoils. This work is supported by DOE Office of Science, Fusion Energy Science under FWP 100182, and SLAC LDRD program.

  15. Creating a Community to Strengthen the Broader Impacts of Condensed Matter Physics Research

    NASA Astrophysics Data System (ADS)

    Adenwalla, Shireen; Bosley, Jocelyn; Voth, Gregory; Smith, Leigh

    The Broader Impacts (BI) merit criteria set out by the National Science Foundation are essential for building the public support necessary for science to flourish. Condensed matter physicists (CMP) have made transformative impacts on our society, but these are often invisible to the public. Communicating the societal benefits of our research can be challenging, because CMP consists of many independent research groups for whom effective engagement in the public arena is not necessarily a forte. Other BI activities, such as engaging K-12 students and teachers to increase scientific literacy and strengthen the STEM workforce, may be very effective, but these are often isolated and short in duration. To increase the visibility of CMP and to make the implementation of BI activities more efficient, we have created a website with two sides: a public side to communicate to a broad audience exciting scientific discoveries in CMP and the technologies they enable, and a private side for condensed matter researchers to communicate with one another about effective broader impact activities. Here we discuss the content of the new website, and the best practices we have identified for communicating the excitement of CMP research to the broadest possible audience. Nsf-DMR 1550737, 1550724 and 1550681.

  16. Going to Extremes: Pulsar Gives Insight on Ultra Dense Matter and Magnetic Fields

    NASA Astrophysics Data System (ADS)

    2004-12-01

    A long look at a young pulsar with NASA's Chandra X-ray Observatory revealed unexpectedly rapid cooling, which suggests that it contains much denser matter than previously expected. The pulsar's cool temperature and the vast magnetic web of high-energy particles that surrounds it have implications for the theory of nuclear matter and the origin of magnetic fields in cosmic objects. Animation: Layers of Chandra's 3-Color Image Animation: Layers of Chandra's 3-Color Image An international team of scientists used the Chandra data to measure the temperature of the pulsar at the center of 3C58, the remains of a star observed to explode in the year 1181. Chandra's image of 3C58 also shows spectacular jets, rings and magnetized loops of high-energy particles generated by the pulsar. "We now have strong evidence that, in slightly more than 800 years, the surface of the 3C58 pulsar has cooled to a temperature of slightly less than a million degrees Celsius," said Patrick Slane of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., and lead author on a paper describing these results in the November 20, 2004 issue of The Astrophysical Journal. "A million degrees may sound pretty hot, but for a young neutron star that's like the frozen tundra in Green Bay, Wisconsin." Optical & Chandra X-ray Composite of 3C58 Optical & Chandra X-ray Composite of 3C58 Pulsars are formed when the central core of a massive star collapses to create a dense object about 15 miles across that is composed almost entirely of neutrons. Collisions between neutrons and other subatomic particles in the interior of the star produce neutrinos that carry away energy as they escape from the star. This cooling process depends critically on the density and type of particles in the interior, so measurements of the surface temperature of pulsars provide a way to probe extreme conditions where densities are so high that our current understanding of how particles interact with one another is limited

  17. WHAT'S the Matter at Rhic?

    NASA Astrophysics Data System (ADS)

    de Cassagnac, Raphael Granier

    I present here a concise review of the experimental results obtained at the Relativistic Heavy Ion Collider (RHIC), which shed light on the hot and dense quark gluon matter produced at these high temperature and density conditions.

  18. Geometrical optics of dense aerosols: forming dense plasma slabs.

    PubMed

    Hay, Michael J; Valeo, Ernest J; Fisch, Nathaniel J

    2013-11-01

    Assembling a freestanding, sharp-edged slab of homogeneous material that is much denser than gas, but much more rarefied than a solid, is an outstanding technological challenge. The solution may lie in focusing a dense aerosol to assume this geometry. However, whereas the geometrical optics of dilute aerosols is a well-developed field, the dense aerosol limit is mostly unexplored. Yet controlling the geometrical optics of dense aerosols is necessary in preparing such a material slab. Focusing dense aerosols is shown here to be possible, but the finite particle density reduces the effective Stokes number of the flow, a critical result for controlled focusing.

  19. Interband and intraband electron kinetics in non-thermal warm dense gold

    NASA Astrophysics Data System (ADS)

    Brennan Brown, Shaughnessy; Chen, Zhijiang; Curry, Chandra; Hering, Philippe; Hoffmann, Matthias C.; Ng, Andrew; Reid, Matthew; Tsui, Ying Y.; Glenzer, Siegfried H.

    2015-11-01

    Single-state warm dense matter may be produced via isochoric heating of thin metal foils using ultrafast high-power lasers. Previous experiments have confirmed that electron temperatures exceed ion temperatures during the initial picoseconds following excitation; however, electron kinetics in non-thermal states preceding establishment of a well-defined electron thermal distribution remain little understood. X-ray and optical probing techniques provide necessary resolution to investigate these electronic properties. Here, we will present a study of electron kinetics in warm dense gold produced by irradiating free-standing 30 nm Au foils with a 400 nm FWHM, 45 fs Ti:Sapphire laser system at SLAC National Accelerator Laboratory. The temporal evolutions of AC conductivity for 400 nm and 800 nm laser pulses are simultaneously determined with sub-100 fs resolution, providing insight into the 5 d-6 s/ p interband and 6 s / p intraband transitions respectively. Our results suggest that Auger decay and three-body recombination play important roles in electron thermalization of warm dense gold.

  20. Interstellar Matter

    NASA Astrophysics Data System (ADS)

    Savage, B.; Murdin, P.

    2000-11-01

    The enormous volume of space between the stars in the Milky Way Galaxy is filled with interstellar matter (ISM). The ISM plays a central role in the processes of STAR FORMATION and GALAXY EVOLUTION. Stars form from the ISM in dense molecular clouds. The radiant and mechanical energy produced by stars heats, ionizes, and produces structures in the ISM. Gradual or catastrophic mass loss from stars ...

  1. Challenges in QCD matter physics -The scientific programme of the Compressed Baryonic Matter experiment at FAIR

    NASA Astrophysics Data System (ADS)

    Ablyazimov, T.; Abuhoza, A.; Adak, R. P.; Adamczyk, M.; Agarwal, K.; Aggarwal, M. M.; Ahammed, Z.; Ahmad, F.; Ahmad, N.; Ahmad, S.; Akindinov, A.; Akishin, P.; Akishina, E.; Akishina, T.; Akishina, V.; Akram, A.; Al-Turany, M.; Alekseev, I.; Alexandrov, E.; Alexandrov, I.; Amar-Youcef, S.; Anđelić, M.; Andreeva, O.; Andrei, C.; Andronic, A.; Anisimov, Yu.; Appelshäuser, H.; Argintaru, D.; Atkin, E.; Avdeev, S.; Averbeck, R.; Azmi, M. D.; Baban, V.; Bach, M.; Badura, E.; Bähr, S.; Balog, T.; Balzer, M.; Bao, E.; Baranova, N.; Barczyk, T.; Bartoş, D.; Bashir, S.; Baszczyk, M.; Batenkov, O.; Baublis, V.; Baznat, M.; Becker, J.; Becker, K.-H.; Belogurov, S.; Belyakov, D.; Bendarouach, J.; Berceanu, I.; Bercuci, A.; Berdnikov, A.; Berdnikov, Y.; Berendes, R.; Berezin, G.; Bergmann, C.; Bertini, D.; Bertini, O.; Beşliu, C.; Bezshyyko, O.; Bhaduri, P. P.; Bhasin, A.; Bhati, A. K.; Bhattacharjee, B.; Bhattacharyya, A.; Bhattacharyya, T. K.; Biswas, S.; Blank, T.; Blau, D.; Blinov, V.; Blume, C.; Bocharov, Yu.; Book, J.; Breitner, T.; Brüning, U.; Brzychczyk, J.; Bubak, A.; Büsching, H.; Bus, T.; Butuzov, V.; Bychkov, A.; Byszuk, A.; Cai, Xu; Cãlin, M.; Cao, Ping; Caragheorgheopol, G.; Carević, I.; Cătănescu, V.; Chakrabarti, A.; Chattopadhyay, S.; Chaus, A.; Chen, Hongfang; Chen, LuYao; Cheng, Jianping; Chepurnov, V.; Cherif, H.; Chernogorov, A.; Ciobanu, M. I.; Claus, G.; Constantin, F.; Csanád, M.; D'Ascenzo, N.; Das, Supriya; Das, Susovan; de Cuveland, J.; Debnath, B.; Dementiev, D.; Deng, Wendi; Deng, Zhi; Deppe, H.; Deppner, I.; Derenovskaya, O.; Deveaux, C. A.; Deveaux, M.; Dey, K.; Dey, M.; Dillenseger, P.; Dobyrn, V.; Doering, D.; Dong, Sheng; Dorokhov, A.; Dreschmann, M.; Drozd, A.; Dubey, A. K.; Dubnichka, S.; Dubnichkova, Z.; Dürr, M.; Dutka, L.; Dželalija, M.; Elsha, V. V.; Emschermann, D.; Engel, H.; Eremin, V.; Eşanu, T.; Eschke, J.; Eschweiler, D.; Fan, Huanhuan; Fan, Xingming; Farooq, M.; Fateev, O.; Feng, Shengqin; Figuli, S. P. D.; Filozova, I.; Finogeev, D.; Fischer, P.; Flemming, H.; Förtsch, J.; Frankenfeld, U.; Friese, V.; Friske, E.; Fröhlich, I.; Frühauf, J.; Gajda, J.; Galatyuk, T.; Gangopadhyay, G.; García Chávez, C.; Gebelein, J.; Ghosh, P.; Ghosh, S. K.; Gläßel, S.; Goffe, M.; Golinka-Bezshyyko, L.; Golovatyuk, V.; Golovnya, S.; Golovtsov, V.; Golubeva, M.; Golubkov, D.; Gómez Ramírez, A.; Gorbunov, S.; Gorokhov, S.; Gottschalk, D.; Gryboś, P.; Grzeszczuk, A.; Guber, F.; Gudima, K.; Gumiński, M.; Gupta, A.; Gusakov, Yu.; Han, Dong; Hartmann, H.; He, Shue; Hehner, J.; Heine, N.; Herghelegiu, A.; Herrmann, N.; Heß, B.; Heuser, J. M.; Himmi, A.; Höhne, C.; Holzmann, R.; Hu, Dongdong; Huang, Guangming; Huang, Xinjie; Hutter, D.; Ierusalimov, A.; Ilgenfritz, E.-M.; Irfan, M.; Ivanischev, D.; Ivanov, M.; Ivanov, P.; Ivanov, Valery; Ivanov, Victor; Ivanov, Vladimir; Ivashkin, A.; Jaaskelainen, K.; Jahan, H.; Jain, V.; Jakovlev, V.; Janson, T.; Jiang, Di; Jipa, A.; Kadenko, I.; Kähler, P.; Kämpfer, B.; Kalinin, V.; Kallunkathariyil, J.; Kampert, K.-H.; Kaptur, E.; Karabowicz, R.; Karavichev, O.; Karavicheva, T.; Karmanov, D.; Karnaukhov, V.; Karpechev, E.; Kasiński, K.; Kasprowicz, G.; Kaur, M.; Kazantsev, A.; Kebschull, U.; Kekelidze, G.; Khan, M. M.; Khan, S. A.; Khanzadeev, A.; Khasanov, F.; Khvorostukhin, A.; Kirakosyan, V.; Kirejczyk, M.; Kiryakov, A.; Kiš, M.; Kisel, I.; Kisel, P.; Kiselev, S.; Kiss, T.; Klaus, P.; Kłeczek, R.; Klein-Bösing, Ch.; Kleipa, V.; Klochkov, V.; Kmon, P.; Koch, K.; Kochenda, L.; Koczoń, P.; Koenig, W.; Kohn, M.; Kolb, B. W.; Kolosova, A.; Komkov, B.; Korolev, M.; Korolko, I.; Kotte, R.; Kovalchuk, A.; Kowalski, S.; Koziel, M.; Kozlov, G.; Kozlov, V.; Kramarenko, V.; Kravtsov, P.; Krebs, E.; Kreidl, C.; Kres, I.; Kresan, D.; Kretschmar, G.; Krieger, M.; Kryanev, A. V.; Kryshen, E.; Kuc, M.; Kucewicz, W.; Kucher, V.; Kudin, L.; Kugler, A.; Kumar, Ajit; Kumar, Ashwini; Kumar, L.; Kunkel, J.; Kurepin, A.; Kurepin, N.; Kurilkin, A.; Kurilkin, P.; Kushpil, V.; Kuznetsov, S.; Kyva, V.; Ladygin, V.; Lara, C.; Larionov, P.; Laso García, A.; Lavrik, E.; Lazanu, I.; Lebedev, A.; Lebedev, S.; Lebedeva, E.; Lehnert, J.; Lehrbach, J.; Leifels, Y.; Lemke, F.; Li, Cheng; Li, Qiyan; Li, Xin; Li, Yuanjing; Lindenstruth, V.; Linnik, B.; Liu, Feng; Lobanov, I.; Lobanova, E.; Löchner, S.; Loizeau, P.-A.; Lone, S. A.; Lucio Martínez, J. A.; Luo, Xiaofeng; Lymanets, A.; Lyu, Pengfei; Maevskaya, A.; Mahajan, S.; Mahapatra, D. P.; Mahmoud, T.; Maj, P.; Majka, Z.; Malakhov, A.; Malankin, E.; Malkevich, D.; Malyatina, O.; Malygina, H.; Mandal, M. M.; Mandal, S.; Manko, V.; Manz, S.; Marin Garcia, A. M.; Markert, J.; Masciocchi, S.; Matulewicz, T.; Meder, L.; Merkin, M.; Mialkovski, V.; Michel, J.; Miftakhov, N.; Mik, L.; Mikhailov, K.; Mikhaylov, V.; Milanović, B.; Militsija, V.; Miskowiec, D.; Momot, I.; Morhardt, T.; Morozov, S.; Müller, W. F. J.; Müntz, C.; Mukherjee, S.; Muñoz Castillo, C. E.; Murin, Yu.; Najman, R.; Nandi, C.; Nandy, E.; Naumann, L.; Nayak, T.; Nedosekin, A.; Negi, V. S.; Niebur, W.; Nikulin, V.; Normanov, D.; Oancea, A.; Oh, Kunsu; Onishchuk, Yu.; Ososkov, G.; Otfinowski, P.; Ovcharenko, E.; Pal, S.; Panasenko, I.; Panda, N. R.; Parzhitskiy, S.; Patel, V.; Pauly, C.; Penschuck, M.; Peshekhonov, D.; Peshekhonov, V.; Petráček, V.; Petri, M.; Petriş, M.; Petrovici, A.; Petrovici, M.; Petrovskiy, A.; Petukhov, O.; Pfeifer, D.; Piasecki, K.; Pieper, J.; Pietraszko, J.; Płaneta, R.; Plotnikov, V.; Plujko, V.; Pluta, J.; Pop, A.; Pospisil, V.; Poźniak, K.; Prakash, A.; Prasad, S. K.; Prokudin, M.; Pshenichnov, I.; Pugach, M.; Pugatch, V.; Querchfeld, S.; Rabtsun, S.; Radulescu, L.; Raha, S.; Rami, F.; Raniwala, R.; Raniwala, S.; Raportirenko, A.; Rautenberg, J.; Rauza, J.; Ray, R.; Razin, S.; Reichelt, P.; Reinecke, S.; Reinefeld, A.; Reshetin, A.; Ristea, C.; Ristea, O.; Rodriguez Rodriguez, A.; Roether, F.; Romaniuk, R.; Rost, A.; Rostchin, E.; Rostovtseva, I.; Roy, Amitava; Roy, Ankhi; Rożynek, J.; Ryabov, Yu.; Sadovsky, A.; Sahoo, R.; Sahu, P. K.; Sahu, S. K.; Saini, J.; Samanta, S.; Sambyal, S. S.; Samsonov, V.; Sánchez Rosado, J.; Sander, O.; Sarangi, S.; Satława, T.; Sau, S.; Saveliev, V.; Schatral, S.; Schiaua, C.; Schintke, F.; Schmidt, C. J.; Schmidt, H. R.; Schmidt, K.; Scholten, J.; Schweda, K.; Seck, F.; Seddiki, S.; Selyuzhenkov, I.; Semennikov, A.; Senger, A.; Senger, P.; Shabanov, A.; Shabunov, A.; Shao, Ming; Sheremetiev, A. D.; Shi, Shusu; Shumeiko, N.; Shumikhin, V.; Sibiryak, I.; Sikora, B.; Simakov, A.; Simon, C.; Simons, C.; Singaraju, R. N.; Singh, A. K.; Singh, B. K.; Singh, C. P.; Singhal, V.; Singla, M.; Sitzmann, P.; Siwek-Wilczyńska, K.; Škoda, L.; Skwira-Chalot, I.; Som, I.; Song, Guofeng; Song, Jihye; Sosin, Z.; Soyk, D.; Staszel, P.; Strikhanov, M.; Strohauer, S.; Stroth, J.; Sturm, C.; Sultanov, R.; Sun, Yongjie; Svirida, D.; Svoboda, O.; Szabó, A.; Szczygieł, R.; Talukdar, R.; Tang, Zebo; Tanha, M.; Tarasiuk, J.; Tarassenkova, O.; Târzilă, M.-G.; Teklishyn, M.; Tischler, T.; Tlustý, P.; Tölyhi, T.; Toia, A.; Topil'skaya, N.; Träger, M.; Tripathy, S.; Tsakov, I.; Tsyupa, Yu.; Turowiecki, A.; Tuturas, N. G.; Uhlig, F.; Usenko, E.; Valin, I.; Varga, D.; Vassiliev, I.; Vasylyev, O.; Verbitskaya, E.; Verhoeven, W.; Veshikov, A.; Visinka, R.; Viyogi, Y. P.; Volkov, S.; Volochniuk, A.; Vorobiev, A.; Voronin, Aleksey; Voronin, Alexander; Vovchenko, V.; Vznuzdaev, M.; Wang, Dong; Wang, Xi-Wei; Wang, Yaping; Wang, Yi; Weber, M.; Wendisch, C.; Wessels, J. P.; Wiebusch, M.; Wiechula, J.; Wielanek, D.; Wieloch, A.; Wilms, A.; Winckler, N.; Winter, M.; Wiśniewski, K.; Wolf, Gy.; Won, Sanguk; Wu, Ke-Jun; Wüstenfeld, J.; Xiang, Changzhou; Xu, Nu; Yang, Junfeng; Yang, Rongxing; Yin, Zhongbao; Yoo, In-Kwon; Yuldashev, B.; Yushmanov, I.; Zabołotny, W.; Zaitsev, Yu.; Zamiatin, N. I.; Zanevsky, Yu.; Zhalov, M.; Zhang, Yifei; Zhang, Yu; Zhao, Lei; Zheng, Jiajun; Zheng, Sheng; Zhou, Daicui; Zhou, Jing; Zhu, Xianglei; Zinchenko, A.; Zipper, W.; Żoładź, M.; Zrelov, P.; Zryuev, V.; Zumbruch, P.; Zyzak, M.

    2017-03-01

    Substantial experimental and theoretical efforts worldwide are devoted to explore the phase diagram of strongly interacting matter. At LHC and top RHIC energies, QCD matter is studied at very high temperatures and nearly vanishing net-baryon densities. There is evidence that a Quark-Gluon-Plasma (QGP) was created at experiments at RHIC and LHC. The transition from the QGP back to the hadron gas is found to be a smooth cross over. For larger net-baryon densities and lower temperatures, it is expected that the QCD phase diagram exhibits a rich structure, such as a first-order phase transition between hadronic and partonic matter which terminates in a critical point, or exotic phases like quarkyonic matter. The discovery of these landmarks would be a breakthrough in our understanding of the strong interaction and is therefore in the focus of various high-energy heavy-ion research programs. The Compressed Baryonic Matter (CBM) experiment at FAIR will play a unique role in the exploration of the QCD phase diagram in the region of high net-baryon densities, because it is designed to run at unprecedented interaction rates. High-rate operation is the key prerequisite for high-precision measurements of multi-differential observables and of rare diagnostic probes which are sensitive to the dense phase of the nuclear fireball. The goal of the CBM experiment at SIS100 (√{s_{NN}}= 2.7-4.9 GeV) is to discover fundamental properties of QCD matter: the phase structure at large baryon-chemical potentials ( μ_B > 500 MeV), effects of chiral symmetry, and the equation of state at high density as it is expected to occur in the core of neutron stars. In this article, we review the motivation for and the physics programme of CBM, including activities before the start of data taking in 2024, in the context of the worldwide efforts to explore high-density QCD matter.

  2. Demonstration of space-resolved x-ray Thomson scattering capability for warm dense matter experiments on the Z accelerator

    DOE PAGES

    Ao, T.; Harding, E. C.; Bailey, J. E.; ...

    2016-01-13

    Experiments on the Sandia Z pulsed-power accelerator demonstrated the ability to produce warm dense matter (WDM) states with unprecedented uniformity, duration, and size, which are ideal for investigations of fundamental WDM properties. For the first time, space-resolved x-ray Thomson scattering (XRTS) spectra from shocked carbon foams were recorded on Z. The large (> 20 MA) electrical current produced by Z was used to launch Al flyer plates up to 25 km/s. The impact of the flyer plate on a CH 2 foam target produced a shocked state with an estimated pressure of 0.75 Mbar, density of 0.52 g/cm 3, andmore » temperature of 4.3 eV. Both unshocked and shocked portions of the foam target were probed with 6.2 keV x-rays produced by focusing the Z-Beamlet laser onto a nearby Mn foil. The data is composed of three spatially distinct spectra that were simultaneously captured with a single spectrometer with high spectral (4.8 eV) and spatial (190 μm) resolutions. Furthermore, these spectra provide detailed information on three target locations: the laser spot, the unshocked foam, and the shocked foam.« less

  3. Ion Heating of Plasma to Warm Dense Matter Conditions for the study of High-Z/Low-Z Mixing

    NASA Astrophysics Data System (ADS)

    Roycroft, R.; Dyer, G. M.; McCary, E.; Wagner, C.; Bernstein, A.; Ditmire, T.; Albright, B. J.; Fernandez, J. C.; Bang, W.; Bradley, P. A.; Gautier, D. C.; Hamilton, C. E.; Palaniyappan, S.; Santiago Cordoba, M. A.; Vold, E. L.; Yin, L.; Hegelich, B. M.

    2016-10-01

    The evolution of the interface between a light and heavy material isochorically heated to warm dense matter conditions is important to the understanding of electrostatic effects on the hydrodynamic models of fluid mixing. In recent experiments at the Trident laser facility, the target, containing a high Z and a low Z material, is heated to around 1eV by laser accelerated aluminum ions. In preparation for continued mixing experiments, we have recently heated aluminum to 20eV by laser accelerated protons on the Texas Petawatt Laser. We fielded a streaked optical pyrometer to measure surface temperature. The pyrometer images the rear surface of a heated target on a sub-nanosecond timescale with 400nm blackbody emissions. This poster presents the details of the experimental setup and pyrometer design, as well as results of ion and proton heating of aluminum targets, and ion heating of high-Z/low-Z integrated targets. Supported by NNSA cooperative agreement DE-NA0002008, the DoE through the LANL LDRD program, the DARPA PULSE program (12-63- PULSE-FP014), and the Air Force Office of Scientific Research (FA9550-14-1-0045).

  4. Nuclear pasta in hot dense matter and its implications for neutrino scattering

    NASA Astrophysics Data System (ADS)

    Roggero, Alessandro; Margueron, Jérôme; Roberts, Luke F.; Reddy, Sanjay

    2018-04-01

    The abundance of large clusters of nucleons in neutron-rich matter at subnuclear density is found to be greatly reduced by finite-temperature effects when matter is close to β equilibrium, compared to the case where the electron fraction is fixed at Ye>0.1 , as often considered in the literature. Large nuclei and exotic nonspherical nuclear configurations called pasta, favored in the vicinity of the transition to uniform matter at T =0 , dissolve at a relatively low temperature Tu as protons leak out of nuclei and pasta. For matter at β equilibrium with a negligible neutrino chemical potential we find that Tuβ≃4 ±1 MeV for realistic equations of state. This is lower than the maximum temperature Tmaxβ≃9 ±1 MeV at which nuclei can coexist with a gas of nucleons and can be explained by a change in the nature of the transition to uniform matter called retrograde condensation. An important new finding is that coherent neutrino scattering from nuclei and pasta makes a modest contribution to the opacity under the conditions encountered in supernovas and neutron star mergers. This is because large nuclear clusters dissolve at most relevant temperatures, and at lower temperatures, when clusters are present, Coulomb correlations between them suppress coherent neutrino scattering off individual clusters. Implications for neutrino signals from galactic supernovas are briefly discussed.

  5. Holographic Quark Matter and Neutron Stars.

    PubMed

    Hoyos, Carlos; Jokela, Niko; Rodríguez Fernández, David; Vuorinen, Aleksi

    2016-07-15

    We use a top-down holographic model for strongly interacting quark matter to study the properties of neutron stars. When the corresponding equation of state (EOS) is matched with state-of-the-art results for dense nuclear matter, we consistently observe a first-order phase transition at densities between 2 and 7 times the nuclear saturation density. Solving the Tolman-Oppenheimer-Volkov equations with the resulting hybrid EOSs, we find maximal stellar masses in excess of two solar masses, albeit somewhat smaller than those obtained with simple extrapolations of the nuclear matter EOSs. Our calculation predicts that no quark matter exists inside neutron stars.

  6. Nuclear pasta in hot dense matter and its implications for neutrino scattering

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Roggero, Alessandro; Margueron, Jerome; Roberts, Luke F.

    The abundance of large clusters of nucleons in neutron-rich matter at subnuclear density is found to be greatly reduced by finite-temperature effects when matter is close to β equilibrium, compared to the case where the electron fraction is fixed at Y e > 0.1 , as often considered in the literature. Large nuclei and exotic nonspherical nuclear configurations called pasta, favored in the vicinity of the transition to uniform matter at T = 0 , dissolve at a relatively low temperature T u as protons leak out of nuclei and pasta. For matter at β-equilibrium with a negligible neutrino chemical potential we find that Tmore » $$β\\atop{u}$$ ≃ 4 ± 1 MeV for realistic equations of state. This is lower than the maximum temperature T$$β\\atop{max}$$ ≃ 9 ± 1 MeV at which nuclei can coexist with a gas of nucleons and can be explained by a change in the nature of the transition to uniform matter called retrograde condensation. An important new finding is that coherent neutrino scattering from nuclei and pasta makes a modest contribution to the opacity under the conditions encountered in supernovas and neutron star mergers. This is because large nuclear clusters dissolve at most relevant temperatures, and at lower temperatures, when clusters are present, Coulomb correlations between them suppress coherent neutrino scattering off individual clusters. Lastly, implications for neutrino signals from galactic supernovas are briefly discussed.« less

  7. Nuclear pasta in hot dense matter and its implications for neutrino scattering

    DOE PAGES

    Roggero, Alessandro; Margueron, Jerome; Roberts, Luke F.; ...

    2018-04-16

    The abundance of large clusters of nucleons in neutron-rich matter at subnuclear density is found to be greatly reduced by finite-temperature effects when matter is close to β equilibrium, compared to the case where the electron fraction is fixed at Y e > 0.1 , as often considered in the literature. Large nuclei and exotic nonspherical nuclear configurations called pasta, favored in the vicinity of the transition to uniform matter at T = 0 , dissolve at a relatively low temperature T u as protons leak out of nuclei and pasta. For matter at β-equilibrium with a negligible neutrino chemical potential we find that Tmore » $$β\\atop{u}$$ ≃ 4 ± 1 MeV for realistic equations of state. This is lower than the maximum temperature T$$β\\atop{max}$$ ≃ 9 ± 1 MeV at which nuclei can coexist with a gas of nucleons and can be explained by a change in the nature of the transition to uniform matter called retrograde condensation. An important new finding is that coherent neutrino scattering from nuclei and pasta makes a modest contribution to the opacity under the conditions encountered in supernovas and neutron star mergers. This is because large nuclear clusters dissolve at most relevant temperatures, and at lower temperatures, when clusters are present, Coulomb correlations between them suppress coherent neutrino scattering off individual clusters. Lastly, implications for neutrino signals from galactic supernovas are briefly discussed.« less

  8. Models of the elastic x-ray scattering feature for warm dense aluminum

    DOE PAGES

    Starrett, Charles Edward; Saumon, Didier

    2015-09-03

    The elastic feature of x-ray scattering from warm dense aluminum has recently been measured by Fletcher et al. [Nature Photonics 9, 274 (2015)] with much higher accuracy than had hitherto been possible. This measurement is a direct test of the ionic structure predicted by models of warm dense matter. We use the method of pseudoatom molecular dynamics to predict this elastic feature for warm dense aluminum with temperatures of 1–100 eV and densities of 2.7–8.1g/cm 3. We compare these predictions to experiments, finding good agreement with Fletcher et al. and corroborating the discrepancy found in analyses of an earlier experimentmore » of Ma et al. [Phys. Rev. Lett. 110, 065001 (2013)]. Lastly, we also evaluate the validity of the Thomas-Fermi model of the electrons and of the hypernetted chain approximation in computing the elastic feature and find them both wanting in the regime currently probed by experiments.« less

  9. Modeling of Dense Plasma Effects in Short-Pulse Laser Experiments

    NASA Astrophysics Data System (ADS)

    Walton, Timothy; Golovkin, Igor; Macfarlane, Joseph; Prism Computational Sciences, Madison, WI Team

    2016-10-01

    Warm and Hot Dense Matter produced in short-pulse laser experiments can be studied with new high resolving power x-ray spectrometers. Data interpretation implies accurate modeling of the early-time heating dynamics and the radiation conditions that are generated. Producing synthetic spectra requires a model that describes the major physical processes that occur inside the target, including the hot-electron generation and relaxation phases and the effect of target heating. An important issue concerns the sensitivity of the predicted K-line shifts to the continuum lowering model that is used. We will present a set of PrismSPECT spectroscopic simulations using various continuum lowering models: Hummer/Mihalas, Stewart-Pyatt, and Ecker-Kroll and discuss their effect on the formation of K-shell features. We will also discuss recently implemented models for dense plasma shifts for H-like, He-like and neutral systems.

  10. A constitutive law for dense granular flows.

    PubMed

    Jop, Pierre; Forterre, Yoël; Pouliquen, Olivier

    2006-06-08

    A continuum description of granular flows would be of considerable help in predicting natural geophysical hazards or in designing industrial processes. However, the constitutive equations for dry granular flows, which govern how the material moves under shear, are still a matter of debate. One difficulty is that grains can behave like a solid (in a sand pile), a liquid (when poured from a silo) or a gas (when strongly agitated). For the two extreme regimes, constitutive equations have been proposed based on kinetic theory for collisional rapid flows, and soil mechanics for slow plastic flows. However, the intermediate dense regime, where the granular material flows like a liquid, still lacks a unified view and has motivated many studies over the past decade. The main characteristics of granular liquids are: a yield criterion (a critical shear stress below which flow is not possible) and a complex dependence on shear rate when flowing. In this sense, granular matter shares similarities with classical visco-plastic fluids such as Bingham fluids. Here we propose a new constitutive relation for dense granular flows, inspired by this analogy and recent numerical and experimental work. We then test our three-dimensional (3D) model through experiments on granular flows on a pile between rough sidewalls, in which a complex 3D flow pattern develops. We show that, without any fitting parameter, the model gives quantitative predictions for the flow shape and velocity profiles. Our results support the idea that a simple visco-plastic approach can quantitatively capture granular flow properties, and could serve as a basic tool for modelling more complex flows in geophysical or industrial applications.

  11. Thomas-Fermi simulations of dense plasmas without pseudopotentials

    NASA Astrophysics Data System (ADS)

    Starrett, C. E.

    2017-07-01

    The Thomas-Fermi model for warm and hot dense matter is widely used to predict material properties such as the equation of state. However, for practical reasons current implementations use pseudopotentials for the electron-nucleus interaction instead of the bare Coulomb potential. This complicates the calculation and quantities such as free energy cannot be converged with respect to the pseudopotential parameters. We present a method that retains the bare Coulomb potential for the electron-nucleus interaction and does not use pseudopotentials. We demonstrate that accurate free energies are obtained by checking variational consistency. Examples for aluminum and iron plasmas are presented.

  12. Dynamic compression of dense oxide (Gd 3Ga 5O 12) from 0.4 to 2.6 TPa: Universal Hugoniot of fluid metals

    DOE PAGES

    Ozaki, N.; Nellis, W. J.; Mashimo, T.; ...

    2016-05-19

    Materials at high pressures and temperatures are of great current interest for warm dense matter physics, planetary sciences, and inertial fusion energy research. Shock-compression equation-of-state data and optical reflectivities of the fluid dense oxide, Gd 3Ga 5O 12 (GGG), were measured at extremely high pressures up to 2.6 TPa (26 Mbar) generated by high-power laser irradiation and magnetically-driven hypervelocity impacts. Above 0.75 TPa, the GGG Hugoniot data approach/reach a universal linear line of fluid metals, and the optical reflectivity most likely reaches a constant value indicating that GGG undergoes a crossover from fluid semiconductor to poor metal with minimum metallicmore » conductivity (MMC). These results suggest that most fluid compounds, e.g., strong planetary oxides, reach a common state on the universal Hugoniot of fluid metals (UHFM) with MMC at sufficiently extreme pressures and temperatures. Lastly, the systematic behaviors of warm dense fluid would be useful benchmarks for developing theoretical equation-of-state and transport models in the warm dense matter regime in determining computational predictions.« less

  13. Dynamic compression of dense oxide (Gd3Ga5O12) from 0.4 to 2.6 TPa: Universal Hugoniot of fluid metals

    PubMed Central

    Ozaki, N.; Nellis, W. J.; Mashimo, T.; Ramzan, M.; Ahuja, R.; Kaewmaraya, T.; Kimura, T.; Knudson, M.; Miyanishi, K.; Sakawa, Y.; Sano, T.; Kodama, R.

    2016-01-01

    Materials at high pressures and temperatures are of great current interest for warm dense matter physics, planetary sciences, and inertial fusion energy research. Shock-compression equation-of-state data and optical reflectivities of the fluid dense oxide, Gd3Ga5O12 (GGG), were measured at extremely high pressures up to 2.6 TPa (26 Mbar) generated by high-power laser irradiation and magnetically-driven hypervelocity impacts. Above 0.75 TPa, the GGG Hugoniot data approach/reach a universal linear line of fluid metals, and the optical reflectivity most likely reaches a constant value indicating that GGG undergoes a crossover from fluid semiconductor to poor metal with minimum metallic conductivity (MMC). These results suggest that most fluid compounds, e.g., strong planetary oxides, reach a common state on the universal Hugoniot of fluid metals (UHFM) with MMC at sufficiently extreme pressures and temperatures. The systematic behaviors of warm dense fluid would be useful benchmarks for developing theoretical equation-of-state and transport models in the warm dense matter regime in determining computational predictions. PMID:27193942

  14. Dynamic compression of dense oxide (Gd3Ga5O12) from 0.4 to 2.6 TPa: Universal Hugoniot of fluid metals.

    PubMed

    Ozaki, N; Nellis, W J; Mashimo, T; Ramzan, M; Ahuja, R; Kaewmaraya, T; Kimura, T; Knudson, M; Miyanishi, K; Sakawa, Y; Sano, T; Kodama, R

    2016-05-19

    Materials at high pressures and temperatures are of great current interest for warm dense matter physics, planetary sciences, and inertial fusion energy research. Shock-compression equation-of-state data and optical reflectivities of the fluid dense oxide, Gd3Ga5O12 (GGG), were measured at extremely high pressures up to 2.6 TPa (26 Mbar) generated by high-power laser irradiation and magnetically-driven hypervelocity impacts. Above 0.75 TPa, the GGG Hugoniot data approach/reach a universal linear line of fluid metals, and the optical reflectivity most likely reaches a constant value indicating that GGG undergoes a crossover from fluid semiconductor to poor metal with minimum metallic conductivity (MMC). These results suggest that most fluid compounds, e.g., strong planetary oxides, reach a common state on the universal Hugoniot of fluid metals (UHFM) with MMC at sufficiently extreme pressures and temperatures. The systematic behaviors of warm dense fluid would be useful benchmarks for developing theoretical equation-of-state and transport models in the warm dense matter regime in determining computational predictions.

  15. Ab initio modeling of nonequilibrium electron-ion dynamics of iron in the warm dense matter regime

    NASA Astrophysics Data System (ADS)

    Ogitsu, T.; Fernandez-Pañella, A.; Hamel, S.; Correa, A. A.; Prendergast, D.; Pemmaraju, C. D.; Ping, Y.

    2018-06-01

    The spatiotemporal electron and ion relaxation dynamics of iron induced by femtosecond laser pulses was studied using a one-dimensional two-temperature model (1D-TTM) where electron and ion temperature-dependent thermophysical parameters such as specific heat (C ), electron-phonon coupling (G ), and thermal conductivity (K ) were calculated with ab initio density-functional-theory (DFT) simulations. Based on the simulated time evolutions of electron and ion temperature distributions [Te(x ,t ) and Ti(x ,t ) ], the time evolution of x-ray absorption near-edge spectroscopy (XANES) was calculated and compared with experimental results reported by Fernandez-Pañella et al., where the slope of XANES spectrum at the onset of absorption (s ) was used due to its excellent sensitivity to the electron temperature. Our results indicate that the ion temperature dependence on G and C , which is largely neglected in the past studies, is very important for studying the nonequilibrium electron-ion relaxation dynamics of iron in warm dense matter (WDM) conditions. It is also shown that the 1 /s behavior becomes very sensitive to the thermal gradient profile, in other words, to the values of K in a TTM simulation, for target thickness of about two to four times the mean free path of conduction electrons. Our approach based on 1D-TTM and XANES simulations can be used to determine the optimal combination of target geometry and laser fluence for a given target material, which will enable us to tightly constrain the thermophysical parameters under electron-ion nonequilibrium WDM conditions.

  16. Memory-Efficient Analysis of Dense Functional Connectomes.

    PubMed

    Loewe, Kristian; Donohue, Sarah E; Schoenfeld, Mircea A; Kruse, Rudolf; Borgelt, Christian

    2016-01-01

    The functioning of the human brain relies on the interplay and integration of numerous individual units within a complex network. To identify network configurations characteristic of specific cognitive tasks or mental illnesses, functional connectomes can be constructed based on the assessment of synchronous fMRI activity at separate brain sites, and then analyzed using graph-theoretical concepts. In most previous studies, relatively coarse parcellations of the brain were used to define regions as graphical nodes. Such parcellated connectomes are highly dependent on parcellation quality because regional and functional boundaries need to be relatively consistent for the results to be interpretable. In contrast, dense connectomes are not subject to this limitation, since the parcellation inherent to the data is used to define graphical nodes, also allowing for a more detailed spatial mapping of connectivity patterns. However, dense connectomes are associated with considerable computational demands in terms of both time and memory requirements. The memory required to explicitly store dense connectomes in main memory can render their analysis infeasible, especially when considering high-resolution data or analyses across multiple subjects or conditions. Here, we present an object-based matrix representation that achieves a very low memory footprint by computing matrix elements on demand instead of explicitly storing them. In doing so, memory required for a dense connectome is reduced to the amount needed to store the underlying time series data. Based on theoretical considerations and benchmarks, different matrix object implementations and additional programs (based on available Matlab functions and Matlab-based third-party software) are compared with regard to their computational efficiency. The matrix implementation based on on-demand computations has very low memory requirements, thus enabling analyses that would be otherwise infeasible to conduct due to

  17. Memory-Efficient Analysis of Dense Functional Connectomes

    PubMed Central

    Loewe, Kristian; Donohue, Sarah E.; Schoenfeld, Mircea A.; Kruse, Rudolf; Borgelt, Christian

    2016-01-01

    The functioning of the human brain relies on the interplay and integration of numerous individual units within a complex network. To identify network configurations characteristic of specific cognitive tasks or mental illnesses, functional connectomes can be constructed based on the assessment of synchronous fMRI activity at separate brain sites, and then analyzed using graph-theoretical concepts. In most previous studies, relatively coarse parcellations of the brain were used to define regions as graphical nodes. Such parcellated connectomes are highly dependent on parcellation quality because regional and functional boundaries need to be relatively consistent for the results to be interpretable. In contrast, dense connectomes are not subject to this limitation, since the parcellation inherent to the data is used to define graphical nodes, also allowing for a more detailed spatial mapping of connectivity patterns. However, dense connectomes are associated with considerable computational demands in terms of both time and memory requirements. The memory required to explicitly store dense connectomes in main memory can render their analysis infeasible, especially when considering high-resolution data or analyses across multiple subjects or conditions. Here, we present an object-based matrix representation that achieves a very low memory footprint by computing matrix elements on demand instead of explicitly storing them. In doing so, memory required for a dense connectome is reduced to the amount needed to store the underlying time series data. Based on theoretical considerations and benchmarks, different matrix object implementations and additional programs (based on available Matlab functions and Matlab-based third-party software) are compared with regard to their computational efficiency. The matrix implementation based on on-demand computations has very low memory requirements, thus enabling analyses that would be otherwise infeasible to conduct due to

  18. First-principles calculations of K-shell X-ray absorption spectra for warm dense nitrogen

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Li, Zi; Zhang, Shen; Kang, Wei

    2016-05-15

    X-ray absorption spectrum is a powerful tool for atomic structure detection on warm dense matter. Here, we perform first-principles molecular dynamics and X-ray absorption spectrum calculations on warm dense nitrogen along a Hugoniot curve. From the molecular dynamics trajectory, the detailed atomic structures are examined for each thermodynamical condition. The K-shell X-ray absorption spectrum is calculated, and its changes with temperature and pressure along the Hugoniot curve are discussed. The warm dense nitrogen systems may contain isolated nitrogen atoms, N{sub 2} molecules, and nitrogen clusters, which show quite different contributions to the total X-ray spectrum due to their different electronmore » density of states. The changes of X-ray spectrum along the Hugoniot curve are caused by the different nitrogen structures induced by the temperature and the pressure. Some clear signatures on X-ray spectrum for different thermodynamical conditions are pointed out, which may provide useful data for future X-ray experiments.« less

  19. Creating the Primordial Quark-Gluon Plasma at the LHC

    NASA Astrophysics Data System (ADS)

    Harris, John W.

    2013-04-01

    Ultra-relativistic collisions of heavy ions at the Large Hadron Collider (LHC) and the Relativistic Heavy Ion Collider (RHIC) create an extremely hot system at temperatures (T) expected only within the first microseconds after the Big Bang. At these temperatures (T ˜ 2 x 10^12 K), a few hundred thousand times hotter than the sun's core, the known ``elementary'' particles cannot exist and matter ``melts'' to form a ``soup'' of quarks and gluons, called the quark-gluon plasma (QGP). This ``soup'' flows easily, with extremely low viscosity, suggesting a nearly perfect hot liquid of quarks and gluons. Furthermore, the liquid is dense, highly interacting and opaque to energetic probes (fast quarks or gluons). RHIC has been in operation for twelve years and has established an impressive set of findings. Recent results from heavy ion collisions at the LHC extend the study of the QGP to higher temperatures and harder probes, such as jets (energetic clusters of particles), particles with extremely large transverse momenta and those containing heavy quarks. I will present a motivation for physics in the field and an overview of the new LHC heavy ion results in relation to results from RHIC.

  20. Strange matter in compact stars

    NASA Astrophysics Data System (ADS)

    Klähn, Thomas; Blaschke, David B.

    2018-02-01

    We discuss possible scenarios for the existence of strange matter in compact stars. The appearance of hyperons leads to a hyperon puzzle in ab-initio approaches based on effective baryon-baryon potentials but is not a severe problem in relativistic mean field models. In general, the puzzle can be resolved in a natural way if hadronic matter gets stiffened at supersaturation densities, an effect based on the quark Pauli quenching between hadrons. We explain the conflict between the necessity to implement dynamical chiral symmetry breaking into a model description and the conditions for the appearance of absolutely stable strange quark matter that require both, approximately masslessness of quarks and a mechanism of confinement. The role of strangeness in compact stars (hadronic or quark matter realizations) remains unsettled. It is not excluded that strangeness plays no role in compact stars at all. To answer the question whether the case of absolutely stable strange quark matter can be excluded on theoretical grounds requires an understanding of dense matter that we have not yet reached.

  1. Isochoric Heating of Solid-Density Matter with an Ultrafast Proton Beam

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Key, M H; Mackinnon, A J; Patel, P K

    A new technique is described for the isochoric heating (i.e., heating at constant volume) of matter to high energy-density plasma states (>10{sup 5} J/g) on a picosecond timescale (10{sup -12} sec). An intense, collimated, ultrashort-pulse beam of protons--generated by a high-intensity laser pulse--is used to isochorically heat a solid density material to a temperature of several eV. The duration of heating is shorter than the timescale for significant hydrodynamic expansion to occur, hence the material is heated to a solid density warm dense plasma state. Using spherically-shaped laser targets a focused proton beam is produced and used to heat amore » smaller volume to over 20 eV. The technique described of ultrafast proton heating provides a unique method for creating isochorically heated high-energy density plasma states.« less

  2. The Continued Reduction in Dense Fog in the Southern California Region: Possible Causes

    NASA Astrophysics Data System (ADS)

    LaDochy, S.; Witiw, M.

    2012-05-01

    Dense fog appears to be decreasing in many parts of the world, especially in western cities. Dense fog (visibility <400 m) is disappearing in the urban southern California area also. There the decrease in dense fog events can be explained mainly by declining particulate levels, Pacific sea surface temperatures (SST), and increased urban warming. Using hourly data from 1948 to the present, we looked at the relationship between fog events in the region and contributing factors and trends over time. Initially a strong relationship was suggested between the occurrence of dense fog and the phases of an atmosphere-ocean cycle: the Pacific Decadal Oscillation (PDO). However, closer analysis revealed the importance to fog variability of an increasing urban heat island and the amount of atmospheric suspended particulate matter. Results show a substantial decrease in the occurrence of very low visibilities (<400 m) at the two airport stations in close proximity to the Pacific Ocean, LAX (Los Angeles International) and LGB (Long Beach International). A downward trend in particulate concentrations, coupled with an upward trend in urban temperatures were associated with the decrease in dense fog occurrence at both LAX and LGB. LAX dense fog that reached over 300 h in 1950 dropped steadily, with 0 h recorded in 1997. Since 1997, there has been a slight recovery with both 2008 and 2009 recording over 30 h of dense fog at both locations. In this study we examine whether the upturn is a temporary reversal of the trend. To remove the urban effect, we also included fog data from Vandenberg Air Force Base (VBG), located in a relatively sparsely populated area approximately 200 km to the north of metropolitan Los Angeles. Particulates, urban heat island, and Pacific SSTs all seem to be contributing factors to the decrease in fog in southern California, along with large-scale atmosphere-ocean interaction cycles. Case studies of local and regional dense fog in southern California point

  3. Equation of state for dense nucleonic matter from metamodeling. I. Foundational aspects

    NASA Astrophysics Data System (ADS)

    Margueron, Jérôme; Hoffmann Casali, Rudiney; Gulminelli, Francesca

    2018-02-01

    Metamodeling for the nucleonic equation of state (EOS), inspired from a Taylor expansion around the saturation density of symmetric nuclear matter, is proposed and parameterized in terms of the empirical parameters. The present knowledge of nuclear empirical parameters is first reviewed in order to estimate their average values and associated uncertainties, and thus defining the parameter space of the metamodeling. They are divided into isoscalar and isovector types, and ordered according to their power in the density expansion. The goodness of the metamodeling is analyzed against the predictions of the original models. In addition, since no correlation among the empirical parameters is assumed a priori, all arbitrary density dependences can be explored, which might not be accessible in existing functionals. Spurious correlations due to the assumed functional form are also removed. This meta-EOS allows direct relations between the uncertainties on the empirical parameters and the density dependence of the nuclear equation of state and its derivatives, and the mapping between the two can be done with standard Bayesian techniques. A sensitivity analysis shows that the more influential empirical parameters are the isovector parameters Lsym and Ksym, and that laboratory constraints at supersaturation densities are essential to reduce the present uncertainties. The present metamodeling for the EOS for nuclear matter is proposed for further applications in neutron stars and supernova matter.

  4. Language (Policy) Matters!

    ERIC Educational Resources Information Center

    Kozleski, E. B.; Mulligan, E.; Hernandez-Saca, D.

    2011-01-01

    Public education has a vital role in ensuring that this and subsequent generations are successful in a global, multilingual economy. In this What Matters brief, we examine how teachers, students, parents, and communities in our nation's schools can create rich opportunities for students to learn. Language (Policy) Matters! includes information and…

  5. Engineered circuit QED with dense resonant modes

    NASA Astrophysics Data System (ADS)

    Wilhelm, Frank; Egger, Daniel

    2013-03-01

    In circuit quantum electrodynamics even in the ultrastrong coupling regime, strong quasi-resonant interaction typically involves only one mode of the resonator as the mode spacing is comparable to the frequency of the mode. We are going to present an engineered hybrid transmission line consisting of a left-handed and a right-handed portion that has a low-frequency van-Hove singularity hence showing a dense mode spectrum at an experimentally accessible point. This gives rise to strong multi-mode coupling and can be utilized in multiple ways to create strongly correlated microwave photons. Supported by DARPA through the QuEST program and by NSERC Discovery grants

  6. Time-Space Position of Warm Dense Matter in Laser Plasma Interaction Process

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cao, L F; Uschmann, I; Forster, E

    2006-09-25

    Laser plasma interaction experiments have been perform performed using an fs Titanium Sapphire laser. Plasmas have been generated from planar PMMA targets using single laser pulses with 3.3 mJ pulse energy, 50 fs pulse duration at 800 nm wavelength. Electron density distributions of the plasmas in different delay times have been characterized by means of Nomarski Interferometry. Experimental data were cautiously compared with relevant 1D numerical simulation. Finally these results provide a first experience of searching for the time-space position of the so-called warm dense plasma in an ultra fast laser target interaction process. These experiments aim to prepare nearmore » solid-density plasmas for Thomson scattering experiments using the short wavelength free-electron laser FLASH, DESY Hamburg.« less

  7. Resolving the Large Scale Spectral Variability of the Luminous Seyfert 1 Galaxy 1H 0419-577: Evidence for a New Emission Component and Absorption by Cold Dense Matter

    NASA Technical Reports Server (NTRS)

    Pounds, K. A.; Reeves, J. N.; Page, K. L.; OBrien, P. T.

    2004-01-01

    An XMM-Newton observation of the luminous Seyfert 1 galaxy 1H 0419-577 in September 2002, when the source was in an extreme low-flux state, found a very hard X-ray spectrum at 1-10 keV with a strong soft excess below -1 keV. Comparison with an earlier XMM-Newton observation when 1H 0419-577 was X-ray bright indicated the dominant spectral variability was due to a steep power law or cool Comptonised thermal emission. Four further XMM-Newton observations, with 1H 0419-577 in intermediate flux states, now support that conclusion, while we also find the variable emission component in intermediate state difference spectra to be strongly modified by absorption in low ionisation matter. The variable soft excess then appears to be an artefact of absorption of the underlying continuum while the core soft emission can be attributed to re- combination in an extended region of more highly ionised gas. We note the wider implications of finding substantial cold dense matter overlying (or embedded in) the X-ray continuum source in a luminous Seyfert 1 galaxy.

  8. Tracking the ultrafast XUV optical properties of x-ray free-electron-laser heated matter with high-order harmonics

    NASA Astrophysics Data System (ADS)

    Williams, Gareth O.; Künzel, S.; Daboussi, S.; Iwan, B.; Gonzalez, A. I.; Boutu, W.; Hilbert, V.; Zastrau, U.; Lee, H. J.; Nagler, B.; Granados, E.; Galtier, E.; Heimann, P.; Barbrel, B.; Dovillaire, G.; Lee, R. W.; Dunn, J.; Recoules, V.; Blancard, C.; Renaudin, P.; de la Varga, A. G.; Velarde, P.; Audebert, P.; Merdji, H.; Zeitoun, Ph.; Fajardo, M.

    2018-02-01

    We present measurements of photon absorption by free electrons as a solid is transformed to plasma. A femtosecond x-ray free-electron laser is used to heat a solid, which separates the electron and ion heating time scales. The changes in absorption are measured with an independent probe pulse created through high-order-harmonic generation. We find an increase in electron temperature to have a relatively small impact on absorption, contrary to several predictions, whereas ion heating increases absorption. We compare the data to current theoretical and numerical approaches and find that a smoother electronic structure yields a better fit to the data, suggestive of a temperature-dependent electronic structure in warm dense matter.

  9. Geometrical Optics of Dense Aerosols

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hay, Michael J.; Valeo, Ernest J.; Fisch, Nathaniel J.

    2013-04-24

    Assembling a free-standing, sharp-edged slab of homogeneous material that is much denser than gas, but much more rare ed than a solid, is an outstanding technological challenge. The solution may lie in focusing a dense aerosol to assume this geometry. However, whereas the geometrical optics of dilute aerosols is a well-developed fi eld, the dense aerosol limit is mostly unexplored. Yet controlling the geometrical optics of dense aerosols is necessary in preparing such a material slab. Focusing dense aerosols is shown here to be possible, but the nite particle density reduces the eff ective Stokes number of the flow, amore » critical result for controlled focusing. __________________________________________________« less

  10. What kind of sQGP is the matter created at RHIC and LHC?

    NASA Astrophysics Data System (ADS)

    Liao, Jinfeng

    2011-10-01

    One of the main discoveries at RHIC is the so-called ``perfect fluid,'' and one of the most interesting things to see at LHC is whether and how such ``perfect fluid'' property will change at much higher collisional energies. I argue these will provide unique opportunity to answer theoretical question about the nature of sQGP. I will discuss two very different scenarios for the QGP in the temperature range from RHIC to LHC: (1) sQGP as a ``see-saw''-QGP of its electric and magnetic components, which is inspired by the deep and generic Electric-Magnetic duality in field theories; (2) sQGP as a super-strong-QGP, which may have a holographic dual in one form or another due to the strong coupling. The two scenarios predict different medium properties (viscosity, and opacity to hard probes) with increasing temperature from RHIC to LHC, therefore making them distinguishable at the upcoming LHC top energy PbPb collisions. The first hints of a possible change in created matter's structure at LHC 2.76TeV collisions as well as expectations for 5.5TeV collisions will be discussed. Supported under DOE Contract No. DE-AC02-98CH10886.

  11. Soft X-ray spectrometer design for warm dense plasma measurements on DARHT Axis-I

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ramey, Nicholas Bryan; Perry, John Oliver; Coleman, Joshua Eugene

    2017-07-11

    A preliminary design study is being performed on a soft X-ray spectrometer to measure K-shell spectra emitted by a warm dense plasma generated on Axis-I of the Dual-Axis Radiographic Hydrodynamic Testing (DARHT) facility at Los Alamos National Laboratory. The 100-ns-long intense, relativistic electron pulse with a beam current of 1.7 kA and energy of 19.8 MeV deposits energy into a thin metal foil heating it to a warm dense plasma. The collisional ionization of the target by the electron beam produces an anisotropic angular distribution of K-shell radiation and a continuum of both scattered electrons and Bremsstrahlung up to themore » beam energy of 19.8 MeV. The principal goal of this project is to characterize these angular distributions to determine the optimal location to deploy the soft X-ray spectrometer. In addition, a proof-of-principle design will be presented. The ultimate goal of the spectrometer is to obtain measurements of the plasma temperature and density to benchmark equation-of-state models of the warm dense matter regime.« less

  12. Anitproton-matter interactions in antiproton applications

    NASA Technical Reports Server (NTRS)

    Morgan, David L., Jr.

    1990-01-01

    By virtue of the highly energetic particles released when they annihilate in matter, antiprotons have a variety of potentially important applications. Among others, these include remote 3-D density and composition imaging of the human body and also of thick, dense materials, cancer therapy, and spacecraft propulsion. Except for spacecraft propulsion, the required numbers of low energy antiprotons can be produced, stored, and transported through reliance on current or near term technology. Paramount to these applications and to fundamental research involving antiprotons is knowledge of how antiprotons interact with matter. The basic annihilation process is fairly well understood, but the antiproton annihilation and energy loss rates in matter depend in complex ways on a number of atomic processes. The rates, and the corresponding cross sections, were measured or are accurately predictable only for limited combinations of antiproton kinetic energy and material species.

  13. Equation of state of dense plasmas with pseudoatom molecular dynamics

    DOE PAGES

    Starrett, C. E.; Saumon, D.

    2016-06-14

    Here, we present an approximation for calculating the equation of state (EOS) of warm and hot dense matter that is built on the previously published pseudoatom molecular dynamics (PAMD) model of dense plasmas [Starrett et al., Phys. Rev. E 91, 013104 (2015)]. And while the EOS calculation with PAMD was previously limited to orbital-free density functional theory (DFT), the new approximation presented here allows a Kohn-Sham DFT treatment of the electrons. The resulting EOS thus includes a quantum mechanical treatment of the electrons with a self-consistent model of the ionic structure, while remaining tractable at high temperatures. The method ismore » validated by comparisons with pressures from ab initio simulations of Be, Al, Si, and Fe. The EOS in the Thomas-Fermi approximation shows remarkable thermodynamic consistency over a wide range of temperatures for aluminum. We also calculate the principal Hugoniots of aluminum and silicon up to 500 eV. We find that the ionic structure of the plasma has a modest effect that peaks at temperatures of a few eV and that the features arising from the electronic structure agree well with ab initio simulations.« less

  14. Tracking the ultrafast XUV optical properties of x-ray free-electron-laser heated matter with high-order harmonics

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Williams, Gareth O.; Künzel, S.; Daboussi, S.

    We present measurements of photon absorption by free electrons as a solid is transformed to plasma. A femtosecond x-ray free-electron laser is used to heat a solid, which separates the electron and ion heating time scales. The changes in absorption are measured with an independent probe pulse created through high-order-harmonic generation. We find an increase in electron temperature to have a relatively small impact on absorption, contrary to several predictions, whereas ion heating increases absorption. Here, we compare the data to current theoretical and numerical approaches and find that a smoother electronic structure yields a better fit to the data,more » suggestive of a temperature-dependent electronic structure in warm dense matter.« less

  15. Tracking the ultrafast XUV optical properties of x-ray free-electron-laser heated matter with high-order harmonics

    DOE PAGES

    Williams, Gareth O.; Künzel, S.; Daboussi, S.; ...

    2018-02-14

    We present measurements of photon absorption by free electrons as a solid is transformed to plasma. A femtosecond x-ray free-electron laser is used to heat a solid, which separates the electron and ion heating time scales. The changes in absorption are measured with an independent probe pulse created through high-order-harmonic generation. We find an increase in electron temperature to have a relatively small impact on absorption, contrary to several predictions, whereas ion heating increases absorption. Here, we compare the data to current theoretical and numerical approaches and find that a smoother electronic structure yields a better fit to the data,more » suggestive of a temperature-dependent electronic structure in warm dense matter.« less

  16. DICCCOL: Dense Individualized and Common Connectivity-Based Cortical Landmarks

    PubMed Central

    Zhu, Dajiang; Guo, Lei; Jiang, Xi; Zhang, Tuo; Zhang, Degang; Chen, Hanbo; Deng, Fan; Faraco, Carlos; Jin, Changfeng; Wee, Chong-Yaw; Yuan, Yixuan; Lv, Peili; Yin, Yan; Hu, Xiaolei; Duan, Lian; Hu, Xintao; Han, Junwei; Wang, Lihong; Shen, Dinggang; Miller, L Stephen

    2013-01-01

    Is there a common structural and functional cortical architecture that can be quantitatively encoded and precisely reproduced across individuals and populations? This question is still largely unanswered due to the vast complexity, variability, and nonlinearity of the cerebral cortex. Here, we hypothesize that the common cortical architecture can be effectively represented by group-wise consistent structural fiber connections and take a novel data-driven approach to explore the cortical architecture. We report a dense and consistent map of 358 cortical landmarks, named Dense Individualized and Common Connectivity–based Cortical Landmarks (DICCCOLs). Each DICCCOL is defined by group-wise consistent white-matter fiber connection patterns derived from diffusion tensor imaging (DTI) data. Our results have shown that these 358 landmarks are remarkably reproducible over more than one hundred human brains and possess accurate intrinsically established structural and functional cross-subject correspondences validated by large-scale functional magnetic resonance imaging data. In particular, these 358 cortical landmarks can be accurately and efficiently predicted in a new single brain with DTI data. Thus, this set of 358 DICCCOL landmarks comprehensively encodes the common structural and functional cortical architectures, providing opportunities for many applications in brain science including mapping human brain connectomes, as demonstrated in this work. PMID:22490548

  17. Role of Nutritional Supplements Complementing Nutrient-Dense Diets: General Versus Sport/Exercise-Specific Dietary Guidelines Related to Energy Expenditure

    NASA Astrophysics Data System (ADS)

    Kleiner, Susan; Greenwood, Mike

    A nutrient-dense diet is a critical aspect in attaining optimal exercise training and athletic performance outcomes. Although including safe and effective nutritional supplements in the dietary design can be extremely helpful in promoting adequate caloric ingestion, they are not sufficient for promoting adequate caloric ingestion based on individualized caloric expenditure needs without the proper diet. Specifically, a strategic and scientifically based nutrient-dense dietary profile should be created by qualified professionals to meet the sport/exercise-specific energy demands of any individual involved in select training intensity protocols. Finally, ingesting the right quantity and quality of nutrient dense calories at precise windows of opportunity becomes vital in attaining desired training and/or competitive performance outcomes.

  18. RHIC The Perfect Liquid

    ScienceCinema

    BNL

    2017-12-09

    Evidence to date suggests that gold-gold collisions the Relativistic Heavy Ion Collider at Brookhaven are indeed creating a new state of hot, dense matter, but one quite different and even more remarkable than had been predicted. Instead of behaving like a gas of free quarks and gluons, as was expected, the matter created in RHIC's heavy ion collisions appears to be more like a "perfect" liquid.

  19. Average-atom treatment of relaxation time in x-ray Thomson scattering from warm dense matter.

    PubMed

    Johnson, W R; Nilsen, J

    2016-03-01

    The influence of finite relaxation times on Thomson scattering from warm dense plasmas is examined within the framework of the average-atom approximation. Presently most calculations use the collision-free Lindhard dielectric function to evaluate the free-electron contribution to the Thomson cross section. In this work, we use the Mermin dielectric function, which includes relaxation time explicitly. The relaxation time is evaluated by treating the average atom as an impurity in a uniform electron gas and depends critically on the transport cross section. The calculated relaxation rates agree well with values inferred from the Ziman formula for the static conductivity and also with rates inferred from a fit to the frequency-dependent conductivity. Transport cross sections determined by the phase-shift analysis in the average-atom potential are compared with those evaluated in the commonly used Born approximation. The Born approximation converges to the exact cross sections at high energies; however, differences that occur at low energies lead to corresponding differences in relaxation rates. The relative importance of including relaxation time when modeling x-ray Thomson scattering spectra is examined by comparing calculations of the free-electron dynamic structure function for Thomson scattering using Lindhard and Mermin dielectric functions. Applications are given to warm dense Be plasmas, with temperatures ranging from 2 to 32 eV and densities ranging from 2 to 64 g/cc.

  20. PREFACE: Many-body correlations from dilute to dense nuclear systems

    NASA Astrophysics Data System (ADS)

    Otsuka, Takaharu; Urban, Michael; Yamada, Taiichi

    2011-09-01

    The International EFES-IN2P3 conference on "Many body correlations from dilute to dense nuclear systems" was held at the Institut Henri Poincaré (IHP), Paris, France, from 15-18 February 2011, on the occasion of the retirement of our colleague Peter Schuck. Correlations play a decisive role in various many-body systems such as nuclear systems, condensed matter and quantum gases. Important examples include: pairing correlations (Cooper pairs) which give rise to nuclear superfluidity (analogous to superconductivity in condensed matter); particle-hole (RPA) correlations in the description of the ground state beyond mean-field theory; clusters; and α-particle correlations in certain nuclei. Also, the nucleons themselves can be viewed as clusters of three quarks. During the past few years, researchers have started to study how the character of these correlations changes with the variation of the density. For instance, the Cooper pairs in dense matter can transform into a Bose-Einstein condensate (BEC) of true bound states at low density (this is the BCS-BEC crossover studied in ultracold Fermi gases). Similar effects play a role in neutron matter at low density, e.g., in the "neutron skin" of exotic nuclei. The α-cluster correlation becomes particularly important at lower density, such as in the excited states of some nuclei (e.g., the α-condensate-like structure in the Hoyle state of 12C) or in the formation of compact stars. In addition to nuclear physics, topics from astrophysics (neutron stars), condensed matter, and quantum gases were discussed in 48 talks and 19 posters, allowing the almost 90 participants from different communities to exchange their ideas, experiences and methods. The conference dinner took place at the Musée d'Orsay, and all the participants enjoyed the very pleasant atmosphere. One session of the conference was dedicated to the celebration of Peter's retirement. We would like to take this opportunity to wish Peter all the best and we hope

  1. Lepton-rich cold QCD matter in protoneutron stars

    NASA Astrophysics Data System (ADS)

    Jiménez, J. C.; Fraga, E. S.

    2018-05-01

    We investigate protoneutron star matter using the state-of-the-art perturbative equation of state for cold and dense QCD in the presence of a fixed lepton fraction in which both electrons and neutrinos are included. Besides computing the modifications in the equation of state due to the presence of trapped neutrinos, we show that stable strange quark matter has a more restricted parameter space. We also study the possibility of nucleation of unpaired quark matter in the core of protoneutron stars by matching the lepton-rich QCD pressure onto a hadronic equation of state, namely TM1 with trapped neutrinos. Using the inherent dependence of perturbative QCD on the renormalization scale parameter, we provide a measure of the uncertainty in the observables we compute.

  2. Stochastic gravitational wave background from newly born massive magnetars: The role of a dense matter equation of state

    NASA Astrophysics Data System (ADS)

    Cheng, Quan; Zhang, Shuang-Nan; Zheng, Xiao-Ping

    2017-04-01

    Newly born massive magnetars are generally considered to be produced by binary neutron star (NS) mergers, which could give rise to short gamma-ray bursts (SGRBs). The strong magnetic fields and fast rotation of these magnetars make them promising sources for gravitational wave (GW) detection using ground based GW interferometers. Based on the observed masses of Galactic NS-NS binaries, by assuming different equations of state (EOSs) of dense matter, we investigate the stochastic gravitational wave background (SGWB) produced by an ensemble of newly born massive magnetars. The massive magnetar formation rate is estimated through: (i) the SGRB formation rate (hereafter entitled as MFR1); (ii) the NS-NS merger rate (hereafter entitled as MFR2). We find that for massive magnetars with masses Mr m =2.4743 M⊙ , if EOS CDDM2 is assumed, the resultant SGWBs may be detected by the future Einstein Telescope (ET) even for MFR1 with minimal local formation rate, and for MFR2 with a local merger rate ρ˙c o(0 )≲10 Mpc-3 Myr-1 . However, if EOS BSk21 is assumed, the SGWB may be detectable by the ET for MFR1 with the maximal local formation rate. Moreover, the background spectra show cutoffs at about 350 Hz in the case of EOS BSk21, and at 124 Hz for CDDM2, respectively. We suggest that if the cutoff at ˜100 Hz in the background spectrum from massive magnetars could be detected, then the quark star EOS CDDM2 seems to be favorable. Moreover, the EOSs, which present relatively small TOV maximum masses, would be excluded.

  3. Creating semiconductor metafilms with designer absorption spectra

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kim, Soo Jin; Fan, Pengyu; Kang, Ju-Hyung

    The optical properties of semiconductors are typically considered intrinsic and fixed. Here we leverage the rapid developments in the field of optical metamaterials to create ultrathin semiconductor metafilms with designer absorption spectra. We show how such metafilms can be constructed by placing one or more types of high-index semiconductor antennas into a dense array with subwavelength spacings. It is argued that the large absorption cross-section of semiconductor antennas and their weak near-field coupling open a unique opportunity to create strongly absorbing metafilms whose spectral absorption properties directly reflect those of the individual antennas. Using experiments and simulations, we demonstrate thatmore » near-unity absorption at one or more target wavelengths of interest can be achieved in a sub-50-nm-thick metafilm using judiciously sized and spaced Ge nanobeams. The ability to create semiconductor metafilms with custom absorption spectra opens up new design strategies for planar optoelectronic devices and solar cells.« less

  4. Thermal conductivity measurements of proton-heated warm dense aluminum

    DOE PAGES

    McKelvey, A.; Kemp, G. E.; Sterne, P. A.; ...

    2017-08-01

    Thermal conductivity is one of the most crucial physical properties of matter when it comes to understanding heat transport, hydrodynamic evolution, and energy balance in systems ranging from astrophysical objects to fusion plasmas. In the warm dense matter regime, experimental data are very scarce so that many theoretical models remain untested. Here we present the first thermal conductivity measurements of aluminum at 0.5–2.7 g/cc and 2–10 eV, using a recently developed platform of differential heating. A temperature gradient is induced in a Au/Al dual-layer target by proton heating, and subsequent heat flow from the hotter Au to the Al rearmore » surface is detected by two simultaneous time-resolved diagnostics. A systematic data set allows for constraining both thermal conductivity and equation-of-state models. Simulations using Purgatorio model or Sesame S27314 for Al thermal conductivity and LEOS for Au/Al release equation-of-state show good agreement with data after 15 ps. Discrepancy still exists at early time 0–15 ps, likely due to non-equilibrium conditions.« less

  5. Thermal conductivity measurements of proton-heated warm dense aluminum

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    McKelvey, A.; Kemp, G. E.; Sterne, P. A.

    Thermal conductivity is one of the most crucial physical properties of matter when it comes to understanding heat transport, hydrodynamic evolution, and energy balance in systems ranging from astrophysical objects to fusion plasmas. In the warm dense matter regime, experimental data are very scarce so that many theoretical models remain untested. Here we present the first thermal conductivity measurements of aluminum at 0.5–2.7 g/cc and 2–10 eV, using a recently developed platform of differential heating. A temperature gradient is induced in a Au/Al dual-layer target by proton heating, and subsequent heat flow from the hotter Au to the Al rearmore » surface is detected by two simultaneous time-resolved diagnostics. A systematic data set allows for constraining both thermal conductivity and equation-of-state models. Simulations using Purgatorio model or Sesame S27314 for Al thermal conductivity and LEOS for Au/Al release equation-of-state show good agreement with data after 15 ps. Discrepancy still exists at early time 0–15 ps, likely due to non-equilibrium conditions.« less

  6. Integrated coherent matter wave circuits

    DOE PAGES

    Ryu, C.; Boshier, M. G.

    2015-09-21

    An integrated coherent matter wave circuit is a single device, analogous to an integrated optical circuit, in which coherent de Broglie waves are created and then launched into waveguides where they can be switched, divided, recombined, and detected as they propagate. Applications of such circuits include guided atom interferometers, atomtronic circuits, and precisely controlled delivery of atoms. We report experiments demonstrating integrated circuits for guided coherent matter waves. The circuit elements are created with the painted potential technique, a form of time-averaged optical dipole potential in which a rapidly moving, tightly focused laser beam exerts forces on atoms through theirmore » electric polarizability. Moreover, the source of coherent matter waves is a Bose–Einstein condensate (BEC). Finally, we launch BECs into painted waveguides that guide them around bends and form switches, phase coherent beamsplitters, and closed circuits. These are the basic elements that are needed to engineer arbitrarily complex matter wave circuitry.« less

  7. Megagauss magnetic fields in ultra-intense laser generated dense plasmas

    NASA Astrophysics Data System (ADS)

    Shaikh, Moniruzzaman; Lad, Amit D.; Jana, Kamalesh; Sarkar, Deep; Dey, Indranuj; Kumar, G. Ravindra

    2017-01-01

    Table-top terawatt lasers can create relativistic light intensities and launch megaampere electron pulses in a solid. These pulses induce megagauss (MG) magnetic pulses, which in turn strongly affect the hot electron transport via electromagnetic instabilities. It is therefore crucial to characterize the MG magnetic fields in great detail. Here, we present measurements of the spatio-temporal evolution of MG magnetic fields produced by a high contrast (picosecond intensity contrast 10-9) laser in a dense plasma on a solid target. The MG magnetic field is measured using the magneto-optic Cotton-Mouton effect, with a time delayed second harmonic (400 nm) probe. The magnetic pulse created by the high contrast laser in a glass target peaks much faster and has a more rapid fall than that induced by a low contrast (10-6) laser.

  8. Know me - a journey in creating a personal electronic health record.

    PubMed

    Buckley, Amanda; Fox, Suzanne

    2015-01-01

    KnowMe is a patient created personal story of key life events both medical and non-medical that enables clinicians to understand what matters to the patient, not what's the matter with them. By shifting the Electronic Health Record (EHR) focus to knowing when a patient was at their best, what's important to them, their personal health goals, and care preferences, clinicians and patients can collaboratively work together in creating a treatment plan that aligns resources tailored to the their needs.

  9. BEC-BCS crossover and the liquid-gas phase transition in hot and dense nuclear matter

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Jin Meng; Urban, Michael; Schuck, Peter

    2010-08-15

    The effect of nucleon-nucleon correlations in symmetric nuclear matter at finite temperature is studied beyond BCS theory. Starting from a Hartree-Fock description of nuclear matter with the Gogny effective interaction, we add correlations corresponding to the formation of preformed pairs and scattering states above the superfluid critical temperature within the in-medium T-matrix approach, which is analogous to the Nozieres-Schmitt-Rink theory. We calculate the critical temperature for a BEC superfluid of deuterons, of a BCS superfluid of nucleons, and in the crossover between these limits. The effect of the correlations on thermodynamic properties (equation of state, energy, entropy) and the liquid-gasmore » phase transition is discussed. Our results show that nucleon-nucleon correlations beyond BCS play an important role for the properties of nuclear matter, especially in the low-density region.« less

  10. Quantum dense key distribution

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Degiovanni, I.P.; Ruo Berchera, I.; Castelletto, S.

    2004-03-01

    This paper proposes a protocol for quantum dense key distribution. This protocol embeds the benefits of a quantum dense coding and a quantum key distribution and is able to generate shared secret keys four times more efficiently than the Bennet-Brassard 1984 protocol. We hereinafter prove the security of this scheme against individual eavesdropping attacks, and we present preliminary experimental results, showing its feasibility.

  11. Dense Breasts

    MedlinePlus

    ... fatty tissue. On a mammogram, fatty tissue appears dark (radio-lucent) and the glandular and connective tissues ... white on mammography) and non-dense fatty tissue (dark on mammography) using a visual scale and assign ...

  12. Average-atom treatment of relaxation time in x-ray Thomson scattering from warm dense matter

    DOE PAGES

    Johnson, W. R.; Nilsen, J.

    2016-03-14

    Here, the influence of finite relaxation times on Thomson scattering from warm dense plasmas is examined within the framework of the average-atom approximation. Presently most calculations use the collision-free Lindhard dielectric function to evaluate the free-electron contribution to the Thomson cross section. In this work, we use the Mermin dielectric function, which includes relaxation time explicitly. The relaxation time is evaluated by treating the average atom as an impurity in a uniform electron gas and depends critically on the transport cross section. The calculated relaxation rates agree well with values inferred from the Ziman formula for the static conductivity andmore » also with rates inferred from a fit to the frequency-dependent conductivity. Transport cross sections determined by the phase-shift analysis in the average-atom potential are compared with those evaluated in the commonly used Born approximation. The Born approximation converges to the exact cross sections at high energies; however, differences that occur at low energies lead to corresponding differences in relaxation rates. The relative importance of including relaxation time when modeling x-ray Thomson scattering spectra is examined by comparing calculations of the free-electron dynamic structure function for Thomson scattering using Lindhard and Mermin dielectric functions. Applications are given to warm dense Be plasmas, with temperatures ranging from 2 to 32 eV and densities ranging from 2 to 64 g/cc.« less

  13. Gamma ray measurements with photoconductive detectors using a dense plasma focus.

    PubMed

    May, M J; Brown, G V; Halvorson, C; Schmidt, A; Bower, D; Tran, B; Lewis, P; Hagen, C

    2014-11-01

    Photons in the MeV range emitted from the dense plasma focus (DPF) at the NSTec North Las Vegas Facility have been measured with both neutron-damaged GaAs and natural diamond photoconductive detectors (PCDs). The DPF creates or "pinches" plasmas of various gases (e.g., H2, D2, Ne, Ar., etc.) that have enough energy to create MeV photons from either bremsstrahlung and/or (n,n(')) reactions if D2 gas is used. The high bandwidth of the PCDs enabled the first ever measurement of the fast micro-pinches present in DPF plasmas. Comparisons between a slower more conventional scintillator/photomultiplier tube based nuclear physics detectors were made to validate the response of the PCDs to fast intense MeV photon signals. Significant discrepancies in the diamond PCD responses were evident.

  14. Dense module enumeration in biological networks

    NASA Astrophysics Data System (ADS)

    Tsuda, Koji; Georgii, Elisabeth

    2009-12-01

    Analysis of large networks is a central topic in various research fields including biology, sociology, and web mining. Detection of dense modules (a.k.a. clusters) is an important step to analyze the networks. Though numerous methods have been proposed to this aim, they often lack mathematical rigorousness. Namely, there is no guarantee that all dense modules are detected. Here, we present a novel reverse-search-based method for enumerating all dense modules. Furthermore, constraints from additional data sources such as gene expression profiles or customer profiles can be integrated, so that we can systematically detect dense modules with interesting profiles. We report successful applications in human protein interaction network analyses.

  15. Numerical Generation of Dense Plume Fingers in Unsaturated Homogeneous Porous Media

    NASA Astrophysics Data System (ADS)

    Cremer, C.; Graf, T.

    2012-04-01

    In nature, the migration of dense plumes typically results in the formation of vertical plume fingers. Flow direction in fingers is downwards, which is counterbalanced by upwards flow of less dense fluid between fingers. In heterogeneous media, heterogeneity itself is known to trigger the formation of fingers. In homogeneous media, however, fingers are also created even if all grains had the same diameter. The reason is that pore-scale heterogeneity leading to different flow velocities also exists in homogeneous media due to two effects: (i) Grains of identical size may randomly arrange differently, e.g. forming tetrahedrons, hexahedrons or octahedrons. Each arrangement creates pores of varying diameter, thus resulting in different average flow velocities. (ii) Random variations of solute concentration lead to varying buoyancy effects, thus also resulting in different velocities. As a continuation of previously made efforts to incorporate pore-scale heterogeneity into fully saturated soil such that dense fingers are realistically generated (Cremer and Graf, EGU Assembly, 2011), the current paper extends the research scope from saturated to unsaturated soil. Perturbation methods are evaluated by numerically re-simulating a laboratory-scale experiment of plume transport in homogeneous unsaturated sand (Simmons et al., Transp. Porous Media, 2002). The following 5 methods are being discussed: (i) homogeneous sand, (ii) initial perturbation of solute concentration, (iii) spatially random, time-constant perturbation of solute source, (iv) spatially and temporally random noise of simulated solute concentration, and (v) random K-field that introduces physically insignificant but numerically significant heterogeneity. Results demonstrate that, as opposed to saturated flow, perturbing the solute source will not result in plume fingering. This is because the location of the perturbed source (domain top) and the location of finger generation (groundwater surface) do not

  16. Dense deconvolution net: Multi path fusion and dense deconvolution for high resolution skin lesion segmentation.

    PubMed

    He, Xinzi; Yu, Zhen; Wang, Tianfu; Lei, Baiying; Shi, Yiyan

    2018-01-01

    Dermoscopy imaging has been a routine examination approach for skin lesion diagnosis. Accurate segmentation is the first step for automatic dermoscopy image assessment. The main challenges for skin lesion segmentation are numerous variations in viewpoint and scale of skin lesion region. To handle these challenges, we propose a novel skin lesion segmentation network via a very deep dense deconvolution network based on dermoscopic images. Specifically, the deep dense layer and generic multi-path Deep RefineNet are combined to improve the segmentation performance. The deep representation of all available layers is aggregated to form the global feature maps using skip connection. Also, the dense deconvolution layer is leveraged to capture diverse appearance features via the contextual information. Finally, we apply the dense deconvolution layer to smooth segmentation maps and obtain final high-resolution output. Our proposed method shows the superiority over the state-of-the-art approaches based on the public available 2016 and 2017 skin lesion challenge dataset and achieves the accuracy of 96.0% and 93.9%, which obtained a 6.0% and 1.2% increase over the traditional method, respectively. By utilizing Dense Deconvolution Net, the average time for processing one testing images with our proposed framework was 0.253 s.

  17. Phase transition temperatures of 405-725 K in superfluid ultra-dense hydrogen clusters on metal surfaces

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Holmlid, Leif, E-mail: holmlid@chem.gu.se; Kotzias, Bernhard

    Ultra-dense hydrogen H(0) with its typical H-H bond distance of 2.3 pm is superfluid at room temperature as expected for quantum fluids. It also shows a Meissner effect at room temperature, which indicates that a transition point to a non-superfluid state should exist above room temperature. This transition point is given by a disappearance of the superfluid long-chain clusters H{sub 2N}(0). This transition point is now measured for several metal carrier surfaces at 405 - 725 K, using both ultra-dense protium p(0) and deuterium D(0). Clusters of ordinary Rydberg matter H(l) as well as small symmetric clusters H{sub 4}(0) andmore » H{sub 3}(0) (which do not give a superfluid or superconductive phase) all still exist on the surface at high temperature. This shows directly that desorption or diffusion processes do not remove the long superfluid H{sub 2N}(0) clusters. The two ultra-dense forms p(0) and D(0) have different transition temperatures under otherwise identical conditions. The transition point for p(0) is higher in temperature, which is unexpected.« less

  18. On describing human white matter anatomy: the white matter query language.

    PubMed

    Wassermann, Demian; Makris, Nikos; Rathi, Yogesh; Shenton, Martha; Kikinis, Ron; Kubicki, Marek; Westin, Carl-Fredrik

    2013-01-01

    The main contribution of this work is the careful syntactical definition of major white matter tracts in the human brain based on a neuroanatomist's expert knowledge. We present a technique to formally describe white matter tracts and to automatically extract them from diffusion MRI data. The framework is based on a novel query language with a near-to-English textual syntax. This query language allows us to construct a dictionary of anatomical definitions describing white matter tracts. The definitions include adjacent gray and white matter regions, and rules for spatial relations. This enables automated coherent labeling of white matter anatomy across subjects. We use our method to encode anatomical knowledge in human white matter describing 10 association and 8 projection tracts per hemisphere and 7 commissural tracts. The technique is shown to be comparable in accuracy to manual labeling. We present results applying this framework to create a white matter atlas from 77 healthy subjects, and we use this atlas in a proof-of-concept study to detect tract changes specific to schizophrenia.

  19. Feshbach Prize: New Phenomena and New Physics from Strongly-Correlated Quantum Matter

    NASA Astrophysics Data System (ADS)

    Carlson, Joseph A.

    2017-01-01

    Strongly correlated quantum matter is ubiquitous in physics from cold atoms to nuclei to the cold dense matter found in neutron stars. Experiments from table-top to the extremely large scale experiments including FRIB and LIGO will help determine the properties of matter across an incredible scale of distances and energies. Questions to be addressed include the existence of exotic states of matter in cold atoms and nuclei, the response of this correlated matter to external probes, and the behavior of matter in extreme astrophysical environments. A more complete understanding is required, both to understand these diverse phenomena and to employ this understanding to probe for new underlying physics in experiments including neutrinoless double beta decay and accelerator neutrino experiments. I will summarize some aspects of our present understanding and highlight several important prospects for the future.

  20. Constructing Dense Graphs with Unique Hamiltonian Cycles

    ERIC Educational Resources Information Center

    Lynch, Mark A. M.

    2012-01-01

    It is not difficult to construct dense graphs containing Hamiltonian cycles, but it is difficult to generate dense graphs that are guaranteed to contain a unique Hamiltonian cycle. This article presents an algorithm for generating arbitrarily large simple graphs containing "unique" Hamiltonian cycles. These graphs can be turned into dense graphs…

  1. Solving the Dark Matter Problem

    ScienceCinema

    Baltz, Ted

    2018-05-11

    Cosmological observations have firmly established that the majority of matter in the universe is of an unknown type, called 'dark matter'. A compelling hypothesis is that the dark matter consists of weakly interacting massive particles (WIMPs) in the mass range around 100 GeV. If the WIMP hypothesis is correct, such particles could be created and studied at accelerators. Furthermore they could be directly detected as the primary component of our galaxy. Solving the dark matter problem requires that the connection be made between the two. We describe some theoretical and experimental avenues that might lead to this connection.

  2. Kinetic Boltzmann approach adapted for modeling highly ionized matter created by x-ray irradiation of a solid.

    PubMed

    Ziaja, Beata; Saxena, Vikrant; Son, Sang-Kil; Medvedev, Nikita; Barbrel, Benjamin; Woloncewicz, Bianca; Stransky, Michal

    2016-05-01

    We report on the kinetic Boltzmann approach adapted for simulations of highly ionized matter created from a solid by its x-ray irradiation. X rays can excite inner-shell electrons, which leads to the creation of deeply lying core holes. Their relaxation, especially in heavier elements, can take complicated paths, leading to a large number of active configurations. Their number can be so large that solving the set of respective evolution equations becomes computationally inefficient and another modeling approach should be used instead. To circumvent this complexity, the commonly used continuum models employ a superconfiguration scheme. Here, we propose an alternative approach which still uses "true" atomic configurations but limits their number by restricting the sample relaxation to the predominant relaxation paths. We test its reliability, performing respective calculations for a bulk material consisting of light atoms and comparing the results with a full calculation including all relaxation paths. Prospective application for heavy elements is discussed.

  3. Self-consistent calculation of the nuclear composition in hot and dense stellar matter

    NASA Astrophysics Data System (ADS)

    Furusawa, Shun; Mishustin, Igor

    2017-03-01

    We investigate the mass fractions and in-medium properties of heavy nuclei in stellar matter at characteristic densities and temperatures for supernova (SN) explosions. The individual nuclei are described within the compressible liquid-drop model taking into account modifications of bulk, surface, and Coulomb energies. The equilibrium properties of nuclei and the full ensemble of heavy nuclei are calculated self-consistently. It is found that heavy nuclei in the ensemble are either compressed or decompressed depending on the isospin asymmetry of the system. The compression or decompression has a little influence on the binding energies, total mass fractions, and average mass numbers of heavy nuclei, although the equilibrium densities of individual nuclei themselves are changed appreciably above one-hundredth of normal nuclear density. We find that nuclear structure in the single-nucleus approximation deviates from the actual one obtained in the multinucleus description, since the density of free nucleons is different between these two descriptions. This study indicates that a multinucleus description is required to realistically account for in-medium effects on the nuclear structure in supernova matter.

  4. Light clusters and pasta phases in warm and dense nuclear matter

    NASA Astrophysics Data System (ADS)

    Avancini, Sidney S.; Ferreira, Márcio; Pais, Helena; Providência, Constança; Röpke, Gerd

    2017-04-01

    The pasta phases are calculated for warm stellar matter in a framework of relativistic mean-field models, including the possibility of light cluster formation. Results from three different semiclassical approaches are compared with a quantum statistical calculation. Light clusters are considered as point-like particles, and their abundances are determined from the minimization of the free energy. The couplings of the light clusters to mesons are determined from experimental chemical equilibrium constants and many-body quantum statistical calculations. The effect of these light clusters on the chemical potentials is also discussed. It is shown that, by including heavy clusters, light clusters are present up to larger nucleonic densities, although with smaller mass fractions.

  5. METHOD OF PRODUCING DENSE CONSOLIDATED METALLIC REGULUS

    DOEpatents

    Magel, T.T.

    1959-08-11

    A methcd is presented for reducing dense metal compositions while simultaneously separating impurities from the reduced dense metal and casting the reduced parified dense metal, such as uranium, into well consolidated metal ingots. The reduction is accomplished by heating the dense metallic salt in the presence of a reducing agent, such as an alkali metal or alkaline earth metal in a bomb type reacting chamber, while applying centrifugal force on the reacting materials. Separation of the metal from the impurities is accomplished essentially by the incorporation of a constricted passageway at the vertex of a conical reacting chamber which is in direct communication with a collecting chamber. When a centrifugal force is applled to the molten metal and slag from the reduction in a direction collinear with the axis of the constricted passage, the dense molten metal is forced therethrough while the less dense slag is retained within the reaction chamber, resulting in a simultaneous separation of the reduced molten metal from the slag and a compacting of the reduced metal in a homogeneous mass.

  6. Thermophysical properties of multi-shock compressed dense argon.

    PubMed

    Chen, Q F; Zheng, J; Gu, Y J; Chen, Y L; Cai, L C; Shen, Z J

    2014-02-21

    In contrast to the single shock compression state that can be obtained directly via experimental measurements, the multi-shock compression states, however, have to be calculated with the aid of theoretical models. In order to determine experimentally the multiple shock states, a diagnostic approach with the Doppler pins system (DPS) and the pyrometer was used to probe multiple shocks in dense argon plasmas. Plasma was generated by a shock reverberation technique. The shock was produced using the flyer plate impact accelerated up to ∼6.1 km/s by a two-stage light gas gun and introduced into the plenum argon gas sample, which was pre-compressed from the environmental pressure to about 20 MPa. The time-resolved optical radiation histories were determined using a multi-wavelength channel optical transience radiance pyrometer. Simultaneously, the particle velocity profiles of the LiF window was measured with multi-DPS. The states of multi-shock compression argon plasma were determined from the measured shock velocities combining the particle velocity profiles. We performed the experiments on dense argon plasmas to determine the principal Hugonoit up to 21 GPa, the re-shock pressure up to 73 GPa, and the maximum measure pressure of the fourth shock up to 158 GPa. The results are used to validate the existing self-consistent variational theory model in the partial ionization region and create new theoretical models.

  7. Thermophysical properties of multi-shock compressed dense argon

    NASA Astrophysics Data System (ADS)

    Chen, Q. F.; Zheng, J.; Gu, Y. J.; Chen, Y. L.; Cai, L. C.; Shen, Z. J.

    2014-02-01

    In contrast to the single shock compression state that can be obtained directly via experimental measurements, the multi-shock compression states, however, have to be calculated with the aid of theoretical models. In order to determine experimentally the multiple shock states, a diagnostic approach with the Doppler pins system (DPS) and the pyrometer was used to probe multiple shocks in dense argon plasmas. Plasma was generated by a shock reverberation technique. The shock was produced using the flyer plate impact accelerated up to ˜6.1 km/s by a two-stage light gas gun and introduced into the plenum argon gas sample, which was pre-compressed from the environmental pressure to about 20 MPa. The time-resolved optical radiation histories were determined using a multi-wavelength channel optical transience radiance pyrometer. Simultaneously, the particle velocity profiles of the LiF window was measured with multi-DPS. The states of multi-shock compression argon plasma were determined from the measured shock velocities combining the particle velocity profiles. We performed the experiments on dense argon plasmas to determine the principal Hugonoit up to 21 GPa, the re-shock pressure up to 73 GPa, and the maximum measure pressure of the fourth shock up to 158 GPa. The results are used to validate the existing self-consistent variational theory model in the partial ionization region and create new theoretical models.

  8. Small scale clustering of late forming dark matter

    NASA Astrophysics Data System (ADS)

    Agarwal, S.; Corasaniti, P.-S.; Das, S.; Rasera, Y.

    2015-09-01

    We perform a study of the nonlinear clustering of matter in the late-forming dark matter (LFDM) scenario in which dark matter results from the transition of a nonminimally coupled scalar field from radiation to collisionless matter. A distinct feature of this model is the presence of a damped oscillatory cutoff in the linear matter power spectrum at small scales. We use a suite of high-resolution N-body simulations to study the imprints of LFDM on the nonlinear matter power spectrum, the halo mass and velocity functions and the halo density profiles. The model largely satisfies high-redshift matter power spectrum constraints from Lyman-α forest measurements, while it predicts suppressed abundance of low-mass halos (˜109- 1010 h-1 M⊙ ) at all redshifts compared to a vanilla Λ CDM model. The analysis of the LFDM halo velocity function shows a better agreement than the Λ CDM prediction with the observed abundance of low-velocity galaxies in the local volume. Halos with mass M ≳1011 h-1 M⊙ show minor departures of the density profiles from Λ CDM expectations, while smaller-mass halos are less dense, consistent with the fact that they form later than their Λ CDM counterparts.

  9. Gravitational lenses and dark matter - Theory

    NASA Technical Reports Server (NTRS)

    Gott, J. Richard, III

    1987-01-01

    Theoretical models are presented for guiding the application of gravitational lenses to probe the characteristics of dark matter in the universe. Analytical techniques are defined for quantifying the mass associated with lensing galaxies (in terms of the image separation), determining the quantity of dark mass of the lensing bodies, and estimating the mass density of the lenses. The possibility that heavy halos are made of low mass stars is considered, along with the swallowing of central images of black holes or cusps in galactic nuclei and the effects produced on a lensed quasar image by nonbaryonic halos. The observable effects of dense groups and clusters and the characteristics of dark matter strings are discussed, and various types of images which are possible due to lensing phenomena and position are described.

  10. Properties of Localized Protons in Neutron Star Matter at Finite Temperatures

    NASA Astrophysics Data System (ADS)

    Szmaglinski, A.; Kubis, S.; Wójcik, W.

    2014-02-01

    We study properties of the proton component of neutron star matter for realistic nuclear models. Vanishing of the nuclear symmetry energy implies proton-neutron separation in dense nuclear matter. Protons which form admixture tend to be localized in potential wells. Here, we extend the description of proton localization to finite temperatures. It appears that the protons are still localized at temperatures typical for hot neutron stars. That fact has important astrophysical consequences. Moreover, the temperature inclusion leads to unexpected results for the behavior of the proton localized state.

  11. Integral equation model for warm and hot dense mixtures.

    PubMed

    Starrett, C E; Saumon, D; Daligault, J; Hamel, S

    2014-09-01

    In a previous work [C. E. Starrett and D. Saumon, Phys. Rev. E 87, 013104 (2013)] a model for the calculation of electronic and ionic structures of warm and hot dense matter was described and validated. In that model the electronic structure of one atom in a plasma is determined using a density-functional-theory-based average-atom (AA) model and the ionic structure is determined by coupling the AA model to integral equations governing the fluid structure. That model was for plasmas with one nuclear species only. Here we extend it to treat plasmas with many nuclear species, i.e., mixtures, and apply it to a carbon-hydrogen mixture relevant to inertial confinement fusion experiments. Comparison of the predicted electronic and ionic structures with orbital-free and Kohn-Sham molecular dynamics simulations reveals excellent agreement wherever chemical bonding is not significant.

  12. Thermal conductivity study of warm dense matter by differential heating on LCLS and Titan

    NASA Astrophysics Data System (ADS)

    Hill, M.; McKelvey, A.; Jiang, S.; Shepherd, R.; Hau-Riege, S.; Whitley, H.; Sterne, P.; Hamel, S.; Collins, G.; Ping, Y.; Brown, C.; Floyd, E.; Fyrth, J.; Hoarty, D.; Hua, R.; Bailly-Grandvaux, M.; Beg, F.; Cho, B.; Kim, M.; Lee, J.; Lee, H.; Galtier, E.

    2017-10-01

    A differential heating platform has been developed for thermal conduction study, where a temperature gradient is induced and subsequent heat flow is probed by time-resolved diagnostics. Multiple experiment using this platform have been carried out at LCLS-MEC and Titan laser facilities for warm dense Al, Fe, amorphous carbon and diamond. Two single-shot time-resolved diagnostics are employed, SOP (streaked optical pyrometry) for surface temperature and FDI (Fourier Domain Interferometry) for surface expansion. Both diagnostics provided excellent data to constrain release equation-of-state (EOS) and thermal conductivity. Data sets with varying target thickness and comparison between simulations with different thermal conductivity models are presented. This work was performed under DOE contract DE-AC52-07NA27344 with support from DOE OFES Early Career program and LLNL LDRD program.

  13. Imaging White Matter in Human Brainstem

    PubMed Central

    Ford, Anastasia A.; Colon-Perez, Luis; Triplett, William T.; Gullett, Joseph M.; Mareci, Thomas H.; FitzGerald, David B.

    2013-01-01

    The human brainstem is critical for the control of many life-sustaining functions, such as consciousness, respiration, sleep, and transfer of sensory and motor information between the brain and the spinal cord. Most of our knowledge about structure and organization of white and gray matter within the brainstem is derived from ex vivo dissection and histology studies. However, these methods cannot be applied to study structural architecture in live human participants. Tractography from diffusion-weighted magnetic resonance imaging (MRI) may provide valuable insights about white matter organization within the brainstem in vivo. However, this method presents technical challenges in vivo due to susceptibility artifacts, functionally dense anatomy, as well as pulsatile and respiratory motion. To investigate the limits of MR tractography, we present results from high angular resolution diffusion imaging of an intact excised human brainstem performed at 11.1 T using isotropic resolution of 0.333, 1, and 2 mm, with the latter reflecting resolution currently used clinically. At the highest resolution, the dense fiber architecture of the brainstem is evident, but the definition of structures degrades as resolution decreases. In particular, the inferred corticopontine/corticospinal tracts (CPT/CST), superior (SCP) and middle cerebellar peduncle (MCP), and medial lemniscus (ML) pathways are clearly discernable and follow known anatomical trajectories at the highest spatial resolution. At lower resolutions, the CST/CPT, SCP, and MCP pathways are artificially enlarged due to inclusion of collinear and crossing fibers not inherent to these three pathways. The inferred ML pathways appear smaller at lower resolutions, indicating insufficient spatial information to successfully resolve smaller fiber pathways. Our results suggest that white matter tractography maps derived from the excised brainstem can be used to guide the study of the brainstem architecture using diffusion MRI

  14. Imaging white matter in human brainstem.

    PubMed

    Ford, Anastasia A; Colon-Perez, Luis; Triplett, William T; Gullett, Joseph M; Mareci, Thomas H; Fitzgerald, David B

    2013-01-01

    The human brainstem is critical for the control of many life-sustaining functions, such as consciousness, respiration, sleep, and transfer of sensory and motor information between the brain and the spinal cord. Most of our knowledge about structure and organization of white and gray matter within the brainstem is derived from ex vivo dissection and histology studies. However, these methods cannot be applied to study structural architecture in live human participants. Tractography from diffusion-weighted magnetic resonance imaging (MRI) may provide valuable insights about white matter organization within the brainstem in vivo. However, this method presents technical challenges in vivo due to susceptibility artifacts, functionally dense anatomy, as well as pulsatile and respiratory motion. To investigate the limits of MR tractography, we present results from high angular resolution diffusion imaging of an intact excised human brainstem performed at 11.1 T using isotropic resolution of 0.333, 1, and 2 mm, with the latter reflecting resolution currently used clinically. At the highest resolution, the dense fiber architecture of the brainstem is evident, but the definition of structures degrades as resolution decreases. In particular, the inferred corticopontine/corticospinal tracts (CPT/CST), superior (SCP) and middle cerebellar peduncle (MCP), and medial lemniscus (ML) pathways are clearly discernable and follow known anatomical trajectories at the highest spatial resolution. At lower resolutions, the CST/CPT, SCP, and MCP pathways are artificially enlarged due to inclusion of collinear and crossing fibers not inherent to these three pathways. The inferred ML pathways appear smaller at lower resolutions, indicating insufficient spatial information to successfully resolve smaller fiber pathways. Our results suggest that white matter tractography maps derived from the excised brainstem can be used to guide the study of the brainstem architecture using diffusion MRI

  15. Is Dark Matter Similar to the Force?

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bernstein, Adam; Vranas, Pavlos

    When Obi Wan Kenobi explained the Force to Luke Skywalker, he said, "It's an energy field created by all living things. It surrounds us and penetrates us; it binds the galaxy together." The same thing could be said of the invisible, elusive, yet ubiquitous dark matter. Explore the similarities and differences between dark matter and the Force and find out why LLNL studies dark matter.

  16. Dynamical theory of dense groups of galaxies

    NASA Technical Reports Server (NTRS)

    Mamon, Gary A.

    1990-01-01

    It is well known that galaxies associate in groups and clusters. Perhaps 40% of all galaxies are found in groups of 4 to 20 galaxies (e.g., Tully 1987). Although most groups appear to be so loose that the galaxy interactions within them ought to be insignificant, the apparently densest groups, known as compact groups appear so dense when seen in projection onto the plane of the sky that their members often overlap. These groups thus appear as dense as the cores of rich clusters. The most popular catalog of compact groups, compiled by Hickson (1982), includes isolation among its selection critera. Therefore, in comparison with the cores of rich clusters, Hickson's compact groups (HCGs) appear to be the densest isolated regions in the Universe (in galaxies per unit volume), and thus provide in principle a clean laboratory for studying the competition of very strong gravitational interactions. The $64,000 question here is then: Are compact groups really bound systems as dense as they appear? If dense groups indeed exist, then one expects that each of the dynamical processes leading to the interaction of their member galaxies should be greatly enhanced. This leads us to the questions: How stable are dense groups? How do they form? And the related question, fascinating to any theorist: What dynamical processes predominate in dense groups of galaxies? If HCGs are not bound dense systems, but instead 1D change alignments (Mamon 1986, 1987; Walke & Mamon 1989) or 3D transient cores (Rose 1979) within larger looser systems of galaxies, then the relevant question is: How frequent are chance configurations within loose groups? Here, the author answers these last four questions after comparing in some detail the methods used and the results obtained in the different studies of dense groups.

  17. Abbreviated Breast MRI and Digital Tomosynthesis Mammography in Screening Women With Dense Breasts | Division of Cancer Prevention

    Cancer.gov

    This randomized phase II trial studies how well abbreviated breast magnetic resonance imaging (MRI) and digital tomosynthesis mammography work in detecting cancer in women with dense breasts. Abbreviated breast MRI is a low cost procedure in which radio waves and a powerful magnet linked to a computer and used to create detailed pictures of the breast in less than 10 minutes.

  18. Repair of Dense Connective Tissues via Biomaterial-Mediated Matrix Reprogramming of the Wound Interface

    PubMed Central

    Qu, Feini; Pintauro, Michael P.; Haughan, Joanne; Henning, Elizabeth A.; Esterhai, John L.; Schaer, Thomas P.; Mauck, Robert L.; Fisher, Matthew B.

    2014-01-01

    Repair of dense connective tissues in adults is limited by their intrinsic hypocellularity and is exacerbated by a dense extracellular matrix (ECM) that impedes cellular migration to and local proliferation at the wound site. Conversely, healing in fetal tissues occurs due in part to an environment conducive to cell mobility and division. Here, we investigated whether the application of a degradative enzyme, collagenase, could reprogram the adult wound margin to a more fetal-like state, and thus abrogate the biophysical impediments that hinder migration and proliferation. We tested this concept using the knee meniscus, a commonly injured structure for which few regenerative approaches exist. To focus delivery and degradation to the wound interface, we developed a system in which collagenase was stored inside poly(ethylene oxide) (PEO) electrospun nanofibers and released upon hydration. Through a series of in vitro and in vivo studies, our findings show that partial digestion of the wound interface improves repair by creating a more compliant and porous microenvironment that expedites cell migration to and/or proliferation at the wound margin. This innovative approach of targeted manipulation of the wound interface, focused on removing the naturally occurring barriers to adult tissue repair, may find widespread application in the treatment of injuries to a variety of dense connective tissues. PMID:25477175

  19. Recognising Axionic Dark Matter by Compton and de-Broglie Scale Modulation of Pulsar Timing

    NASA Astrophysics Data System (ADS)

    De Martino, Ivan; Broadhurst, Tom; Tye, S.-H. Henry; Chiueh, Tzihong; Schive, Hsi-Yu; Lazkoz, Ruth

    2017-11-01

    Light Axionic Dark Matter, motivated by string theory, is increasingly favored for the "no-WIMP era". Galaxy formation is suppressed below a Jeans scale, of ≃ 10^8 M_⊙ by setting the axion mass to, m_B ˜ 10^{-22}eV, and the large dark cores of dwarf galaxies are explained as solitons on the de-Broglie scale. This is persuasive, but detection of the inherent scalar field oscillation at the Compton frequency, ω_B= (2.5 months)^{-1}(m_B/10^{-22}eV), would be definitive. By evolving the coupled Schrödinger-Poisson equation for a Bose-Einstein condensate, we predict the dark matter is fully modulated by de-Broglie interference, with a dense soliton core of size ≃ 150pc, at the Galactic center. The oscillating field pressure induces General Relativistic time dilation in proportion to the local dark matter density and pulsars within this dense core have detectably large timing residuals, of ≃ 400nsec/(m_B/10^{-22}eV). This is encouraging as many new pulsars should be discovered near the Galactic center with planned radio surveys. More generally, over the whole Galaxy, differences in dark matter density between pairs of pulsars imprints a pairwise Galactocentric signature that can be distinguished from an isotropic gravitational wave background.

  20. Cosmic-ray ionisation of dense molecular clouds

    NASA Astrophysics Data System (ADS)

    Vaupre, Solenn

    2015-07-01

    Cosmic rays (CR) are of tremendous importance in the dynamical and chemical evolution of interstellar molecular clouds, where stars and planets form. CRs are likely accelerated in the shells of supernova remnants (SNR), thus molecular clouds nearby can be irradiated by intense fluxes of CRs. CR protons have two major effects on dense molecular clouds: 1) when they encounter the dense medium, high-energy protons (>280 MeV) create pions that decay into gamma-rays. This process makes SNR-molecular cloud associations intense GeV and/or TeV sources whose spectra mimic the CR spectrum. 2) at lower energies, CRs penetrate the cloud and ionise the gas, leading to the formation of molecular species characteristic of the presence of CRs, called tracers of the ionisation. Studying these tracers gives information on low-energy CRs that are unaccessible to any other observations. I studied the CR ionisation of molecular clouds next to three SNRs: W28, W51C and W44. These SNRs are known to be interacting with the nearby clouds, from the presence of shocked gas, OH masers and pion-decay induced gamma-ray emission. My work includes millimeter observations and chemical modeling of tracers of the ionisation in these dense molecular clouds. In these three regions, we determined an enhanced CR ionisation rate, supporting the hypothesis of an origin of the CRs in the SNR nearby. The evolution of the CR ionisation rate with the distance to the SNR brings valuable constraints on the propagation properties of low-energy CRs. The method used relies on observations of the molecular ions HCO+ and DCO+, which shows crucial limitations at high ionisation. Therefore, I investigated, both through modeling and observations, the chemical abundances of several other species to try and identity alternative tracers of the ionisation. In particular, in the W44 region, observations of N2H+ bring additional constraints on the physical conditions, volatile abundances in the cloud, and the ionisation

  1. Maximally dense packings of two-dimensional convex and concave noncircular particles.

    PubMed

    Atkinson, Steven; Jiao, Yang; Torquato, Salvatore

    2012-09-01

    Dense packings of hard particles have important applications in many fields, including condensed matter physics, discrete geometry, and cell biology. In this paper, we employ a stochastic search implementation of the Torquato-Jiao adaptive-shrinking-cell (ASC) optimization scheme [Nature (London) 460, 876 (2009)] to find maximally dense particle packings in d-dimensional Euclidean space R(d). While the original implementation was designed to study spheres and convex polyhedra in d≥3, our implementation focuses on d=2 and extends the algorithm to include both concave polygons and certain complex convex or concave nonpolygonal particle shapes. We verify the robustness of this packing protocol by successfully reproducing the known putative optimal packings of congruent copies of regular pentagons and octagons, then employ it to suggest dense packing arrangements of congruent copies of certain families of concave crosses, convex and concave curved triangles (incorporating shapes resembling the Mercedes-Benz logo), and "moonlike" shapes. Analytical constructions are determined subsequently to obtain the densest known packings of these particle shapes. For the examples considered, we find that the densest packings of both convex and concave particles with central symmetry are achieved by their corresponding optimal Bravais lattice packings; for particles lacking central symmetry, the densest packings obtained are nonlattice periodic packings, which are consistent with recently-proposed general organizing principles for hard particles. Moreover, we find that the densest known packings of certain curved triangles are periodic with a four-particle basis, and we find that the densest known periodic packings of certain moonlike shapes possess no inherent symmetries. Our work adds to the growing evidence that particle shape can be used as a tuning parameter to achieve a diversity of packing structures.

  2. Maximally dense packings of two-dimensional convex and concave noncircular particles

    NASA Astrophysics Data System (ADS)

    Atkinson, Steven; Jiao, Yang; Torquato, Salvatore

    2012-09-01

    Dense packings of hard particles have important applications in many fields, including condensed matter physics, discrete geometry, and cell biology. In this paper, we employ a stochastic search implementation of the Torquato-Jiao adaptive-shrinking-cell (ASC) optimization scheme [Nature (London)NATUAS0028-083610.1038/nature08239 460, 876 (2009)] to find maximally dense particle packings in d-dimensional Euclidean space Rd. While the original implementation was designed to study spheres and convex polyhedra in d≥3, our implementation focuses on d=2 and extends the algorithm to include both concave polygons and certain complex convex or concave nonpolygonal particle shapes. We verify the robustness of this packing protocol by successfully reproducing the known putative optimal packings of congruent copies of regular pentagons and octagons, then employ it to suggest dense packing arrangements of congruent copies of certain families of concave crosses, convex and concave curved triangles (incorporating shapes resembling the Mercedes-Benz logo), and “moonlike” shapes. Analytical constructions are determined subsequently to obtain the densest known packings of these particle shapes. For the examples considered, we find that the densest packings of both convex and concave particles with central symmetry are achieved by their corresponding optimal Bravais lattice packings; for particles lacking central symmetry, the densest packings obtained are nonlattice periodic packings, which are consistent with recently-proposed general organizing principles for hard particles. Moreover, we find that the densest known packings of certain curved triangles are periodic with a four-particle basis, and we find that the densest known periodic packings of certain moonlike shapes possess no inherent symmetries. Our work adds to the growing evidence that particle shape can be used as a tuning parameter to achieve a diversity of packing structures.

  3. MobileFusion: real-time volumetric surface reconstruction and dense tracking on mobile phones.

    PubMed

    Ondrúška, Peter; Kohli, Pushmeet; Izadi, Shahram

    2015-11-01

    We present the first pipeline for real-time volumetric surface reconstruction and dense 6DoF camera tracking running purely on standard, off-the-shelf mobile phones. Using only the embedded RGB camera, our system allows users to scan objects of varying shape, size, and appearance in seconds, with real-time feedback during the capture process. Unlike existing state of the art methods, which produce only point-based 3D models on the phone, or require cloud-based processing, our hybrid GPU/CPU pipeline is unique in that it creates a connected 3D surface model directly on the device at 25Hz. In each frame, we perform dense 6DoF tracking, which continuously registers the RGB input to the incrementally built 3D model, minimizing a noise aware photoconsistency error metric. This is followed by efficient key-frame selection, and dense per-frame stereo matching. These depth maps are fused volumetrically using a method akin to KinectFusion, producing compelling surface models. For each frame, the implicit surface is extracted for live user feedback and pose estimation. We demonstrate scans of a variety of objects, and compare to a Kinect-based baseline, showing on average ∼ 1.5cm error. We qualitatively compare to a state of the art point-based mobile phone method, demonstrating an order of magnitude faster scanning times, and fully connected surface models.

  4. Mining connected global and local dense subgraphs for bigdata

    NASA Astrophysics Data System (ADS)

    Wu, Bo; Shen, Haiying

    2016-01-01

    The problem of discovering connected dense subgraphs of natural graphs is important in data analysis. Discovering dense subgraphs that do not contain denser subgraphs or are not contained in denser subgraphs (called significant dense subgraphs) is also critical for wide-ranging applications. In spite of many works on discovering dense subgraphs, there are no algorithms that can guarantee the connectivity of the returned subgraphs or discover significant dense subgraphs. Hence, in this paper, we define two subgraph discovery problems to discover connected and significant dense subgraphs, propose polynomial-time algorithms and theoretically prove their validity. We also propose an algorithm to further improve the time and space efficiency of our basic algorithm for discovering significant dense subgraphs in big data by taking advantage of the unique features of large natural graphs. In the experiments, we use massive natural graphs to evaluate our algorithms in comparison with previous algorithms. The experimental results show the effectiveness of our algorithms for the two problems and their efficiency. This work is also the first that reveals the physical significance of significant dense subgraphs in natural graphs from different domains.

  5. Deterministic quantum dense coding networks

    NASA Astrophysics Data System (ADS)

    Roy, Saptarshi; Chanda, Titas; Das, Tamoghna; Sen(De), Aditi; Sen, Ujjwal

    2018-07-01

    We consider the scenario of deterministic classical information transmission between multiple senders and a single receiver, when they a priori share a multipartite quantum state - an attempt towards building a deterministic dense coding network. Specifically, we prove that in the case of two or three senders and a single receiver, generalized Greenberger-Horne-Zeilinger (gGHZ) states are not beneficial for sending classical information deterministically beyond the classical limit, except when the shared state is the GHZ state itself. On the other hand, three- and four-qubit generalized W (gW) states with specific parameters as well as the four-qubit Dicke states can provide a quantum advantage of sending the information in deterministic dense coding. Interestingly however, numerical simulations in the three-qubit scenario reveal that the percentage of states from the GHZ-class that are deterministic dense codeable is higher than that of states from the W-class.

  6. Catalysis of partial chiral symmetry restoration by Δ matter

    NASA Astrophysics Data System (ADS)

    Takeda, Yusuke; Kim, Youngman; Harada, Masayasu

    2018-06-01

    We study the phase structure of dense hadronic matter including Δ (1232 ) as well as N (939 ) based on the parity partner structure, where the baryons have their chiral partners with a certain amount of chiral invariant masses. We show that, in symmetric matter, Δ enters into matter in the density region of about one to four times normal nuclear matter density, ρB˜1 -4 ρ0 . The onset density of Δ matter depends on the chiral invariant mass of Δ ,mΔ 0 : As mΔ 0 increases, the onset density becomes bigger. The stable Δ -nucleon matter is realized for ρB≳1.5 ρ0 , i.e., the phase transition from nuclear matter to Δ -nucleon matter is of first order for small mΔ 0, and it is of second order for large mΔ 0. We find that, associated with the phase transition, the chiral condensate changes very rapidly; i.e., the chiral symmetry restoration is accelerated by Δ matter. As a result of the accelerations, there appear N*(1535 ) and Δ (1700 ) , which are the chiral partners to N (939 ) and Δ (1232 ) , in high-density matter, signaling the partial chiral symmetry restoration. Furthermore, we find that complete chiral symmetry restoration itself is delayed by Δ matter. We also calculate the effective masses, pressure, and symmetry energy to study how the transition to Δ matter affects such physical quantities. We observe that the physical quantities change drastically at the transition density.

  7. Organizing principles for dense packings of nonspherical hard particles: Not all shapes are created equal

    NASA Astrophysics Data System (ADS)

    Torquato, Salvatore; Jiao, Yang

    2012-07-01

    We have recently devised organizing principles to obtain maximally dense packings of the Platonic and Archimedean solids and certain smoothly shaped convex nonspherical particles [Torquato and Jiao, Phys. Rev. EPLEEE81539-375510.1103/PhysRevE.81.041310 81, 041310 (2010)]. Here we generalize them in order to guide one to ascertain the densest packings of other convex nonspherical particles as well as concave shapes. Our generalized organizing principles are explicitly stated as four distinct propositions. All of our organizing principles are applied to and tested against the most comprehensive set of both convex and concave particle shapes examined to date, including Catalan solids, prisms, antiprisms, cylinders, dimers of spheres, and various concave polyhedra. We demonstrate that all of the densest known packings associated with this wide spectrum of nonspherical particles are consistent with our propositions. Among other applications, our general organizing principles enable us to construct analytically the densest known packings of certain convex nonspherical particles, including spherocylinders, “lens-shaped” particles, square pyramids, and rhombic pyramids. Moreover, we show how to apply these principles to infer the high-density equilibrium crystalline phases of hard convex and concave particles. We also discuss the unique packing attributes of maximally random jammed packings of nonspherical particles.

  8. Shape-programmable magnetic soft matter

    PubMed Central

    Lum, Guo Zhan; Ye, Zhou; Dong, Xiaoguang; Marvi, Hamid; Erin, Onder; Hu, Wenqi; Sitti, Metin

    2016-01-01

    Shape-programmable matter is a class of active materials whose geometry can be controlled to potentially achieve mechanical functionalities beyond those of traditional machines. Among these materials, magnetically actuated matter is particularly promising for achieving complex time-varying shapes at small scale (overall dimensions smaller than 1 cm). However, previous work can only program these materials for limited applications, as they rely solely on human intuition to approximate the required magnetization profile and actuating magnetic fields for their materials. Here, we propose a universal programming methodology that can automatically generate the required magnetization profile and actuating fields for soft matter to achieve new time-varying shapes. The universality of the proposed method can therefore inspire a vast number of miniature soft devices that are critical in robotics, smart engineering surfaces and materials, and biomedical devices. Our proposed method includes theoretical formulations, computational strategies, and fabrication procedures for programming magnetic soft matter. The presented theory and computational method are universal for programming 2D or 3D time-varying shapes, whereas the fabrication technique is generic only for creating planar beams. Based on the proposed programming method, we created a jellyfish-like robot, a spermatozoid-like undulating swimmer, and an artificial cilium that could mimic the complex beating patterns of its biological counterpart. PMID:27671658

  9. Shape-programmable magnetic soft matter.

    PubMed

    Lum, Guo Zhan; Ye, Zhou; Dong, Xiaoguang; Marvi, Hamid; Erin, Onder; Hu, Wenqi; Sitti, Metin

    2016-10-11

    Shape-programmable matter is a class of active materials whose geometry can be controlled to potentially achieve mechanical functionalities beyond those of traditional machines. Among these materials, magnetically actuated matter is particularly promising for achieving complex time-varying shapes at small scale (overall dimensions smaller than 1 cm). However, previous work can only program these materials for limited applications, as they rely solely on human intuition to approximate the required magnetization profile and actuating magnetic fields for their materials. Here, we propose a universal programming methodology that can automatically generate the required magnetization profile and actuating fields for soft matter to achieve new time-varying shapes. The universality of the proposed method can therefore inspire a vast number of miniature soft devices that are critical in robotics, smart engineering surfaces and materials, and biomedical devices. Our proposed method includes theoretical formulations, computational strategies, and fabrication procedures for programming magnetic soft matter. The presented theory and computational method are universal for programming 2D or 3D time-varying shapes, whereas the fabrication technique is generic only for creating planar beams. Based on the proposed programming method, we created a jellyfish-like robot, a spermatozoid-like undulating swimmer, and an artificial cilium that could mimic the complex beating patterns of its biological counterpart.

  10. Shape-programmable magnetic soft matter

    NASA Astrophysics Data System (ADS)

    Zhan Lum, Guo; Ye, Zhou; Dong, Xiaoguang; Marvi, Hamid; Erin, Onder; Hu, Wenqi; Sitti, Metin

    2016-10-01

    Shape-programmable matter is a class of active materials whose geometry can be controlled to potentially achieve mechanical functionalities beyond those of traditional machines. Among these materials, magnetically actuated matter is particularly promising for achieving complex time-varying shapes at small scale (overall dimensions smaller than 1 cm). However, previous work can only program these materials for limited applications, as they rely solely on human intuition to approximate the required magnetization profile and actuating magnetic fields for their materials. Here, we propose a universal programming methodology that can automatically generate the required magnetization profile and actuating fields for soft matter to achieve new time-varying shapes. The universality of the proposed method can therefore inspire a vast number of miniature soft devices that are critical in robotics, smart engineering surfaces and materials, and biomedical devices. Our proposed method includes theoretical formulations, computational strategies, and fabrication procedures for programming magnetic soft matter. The presented theory and computational method are universal for programming 2D or 3D time-varying shapes, whereas the fabrication technique is generic only for creating planar beams. Based on the proposed programming method, we created a jellyfish-like robot, a spermatozoid-like undulating swimmer, and an artificial cilium that could mimic the complex beating patterns of its biological counterpart.

  11. Supernovae as probes of cosmic parameters: estimating the bias from under-dense lines of sight

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Busti, V.C.; Clarkson, C.; Holanda, R.F.L., E-mail: vinicius.busti@uct.ac.za, E-mail: holanda@uepb.edu.br, E-mail: chris.clarkson@uct.ac.za

    2013-11-01

    Correctly interpreting observations of sources such as type Ia supernovae (SNe Ia) require knowledge of the power spectrum of matter on AU scales — which is very hard to model accurately. Because under-dense regions account for much of the volume of the universe, light from a typical source probes a mean density significantly below the cosmic mean. The relative sparsity of sources implies that there could be a significant bias when inferring distances of SNe Ia, and consequently a bias in cosmological parameter estimation. While the weak lensing approximation should in principle give the correct prediction for this, linear perturbationmore » theory predicts an effectively infinite variance in the convergence for ultra-narrow beams. We attempt to quantify the effect typically under-dense lines of sight might have in parameter estimation by considering three alternative methods for estimating distances, in addition to the usual weak lensing approximation. We find in each case this not only increases the errors in the inferred density parameters, but also introduces a bias in the posterior value.« less

  12. K-Shell Photoabsorption Edge of Strongly Coupled Matter Driven by Laser-Converted Radiation

    NASA Astrophysics Data System (ADS)

    Zhao, Yang; Yang, Jiamin; Zhang, Jiyan; Yang, Guohong; Wei, Minxi; Xiong, Gang; Song, Tianming; Zhang, Zhiyu; Bao, Lihua; Deng, Bo; Li, Yukun; He, Xiaoan; Li, Chaoguang; Mei, Yu; Yu, Ruizhen; Jiang, Shaoen; Liu, Shenye; Ding, Yongkun; Zhang, Baohan

    2013-10-01

    The first observation of the K-shell photoabsorption edge of strongly coupled matter with an ion-ion coupling parameter of about 65 generated by intense x-ray radiation-driven shocks is reported. The soft x-ray radiation generated by laser interaction with a “dog bone” high-Z hohlraum is used to ablate two thick CH layers, which cover a KCl sample, to create symmetrical inward shocks. While the two shocks impact at the central KCl sample, a highly compressed KCl is obtained with a density of 3-5 times solid density and a temperature of about 2-4 eV. The photoabsorption spectra of chlorine near the K-shell edge are measured with a crystal spectrometer using a short x-ray backlighter. The redshift of the K edge up to 11.7 eV and broadening of 15.2 eV are obtained for the maximum compression. A comparison of the measured redshifts and broadenings with dense plasma calculations are made, and it indicates potential improvements in the theoretical description.

  13. Design and Construction of a Dense Plasma Focus Device

    DTIC Science & Technology

    1976-10-01

    This paper deals with the design of a dense plasma focus device as an engineering project. Essentially this approach can be summarized as follows...First, an introduction dealing with a general discussion of plasma devices focusing on the role of a dense plasma focus device as a useful tool in...future research; second, an explanation of the operation of the dense plasma focus ; third, a general design discussion of the dense plasma focus device

  14. Precombination Cloud Collapse and Baryonic Dark Matter

    NASA Technical Reports Server (NTRS)

    Hogan, Craig J.

    1993-01-01

    A simple spherical model of dense baryon clouds in the hot big bang 'strongly nonlinear primordial isocurvature baryon fluctuations' is reviewed and used to describe the dependence of cloud behavior on the model parameters, baryon mass, and initial over-density. Gravitational collapse of clouds before and during recombination is considered including radiation diffusion and trapping, remnant type and mass, and effects on linear large-scale fluctuation modes. Sufficiently dense clouds collapse early into black holes with a minimum mass of approx. 1 solar mass, which behave dynamically like collisionless cold dark matter. Clouds below a critical over-density, however, delay collapse until recombination, remaining until then dynamically coupled to the radiation like ordinary diffuse baryons, and possibly producing remnants of other kinds and lower mass. The mean density in either type of baryonic remnant is unconstrained by observed element abundances. However, mixed or unmixed spatial variations in abundance may survive in the diffuse baryon and produce observable departures from standard predictions.

  15. Ab initio simulations of the dynamic ion structure factor of warm dense lithium

    DOE PAGES

    Witte, B. B. L.; Shihab, M.; Glenzer, S. H.; ...

    2017-04-06

    Here, we present molecular dynamics simulations based on finite-temperature density functional theory that determine self-consistently the dynamic ion structure factor and the electronic form factor in lithium. Our comprehensive data set allows for the calculation of the dispersion relation for collective excitations, the calculation of the sound velocity, and the determination of the ion feature from the total electronic form factor and the ion structure factor. The results are compared with available experimental x-ray and neutron scattering data. Good agreement is found for both the liquid metal and warm dense matter domain. Finally, we study the impact of possible targetmore » inhomogeneities on x-ray scattering spectra.« less

  16. Ab initio simulations of the dynamic ion structure factor of warm dense lithium

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Witte, B. B. L.; Shihab, M.; Glenzer, S. H.

    Here, we present molecular dynamics simulations based on finite-temperature density functional theory that determine self-consistently the dynamic ion structure factor and the electronic form factor in lithium. Our comprehensive data set allows for the calculation of the dispersion relation for collective excitations, the calculation of the sound velocity, and the determination of the ion feature from the total electronic form factor and the ion structure factor. The results are compared with available experimental x-ray and neutron scattering data. Good agreement is found for both the liquid metal and warm dense matter domain. Finally, we study the impact of possible targetmore » inhomogeneities on x-ray scattering spectra.« less

  17. Dark Energy and Dark Matter Phenomena and the Universe with Variable Gravitational Mass

    NASA Astrophysics Data System (ADS)

    Gorkavyi, N.

    2005-12-01

    Generation of high-frequency gravitational waves near the singularity is a crucial factor for understanding the origin and dynamics of the Universe. Emission of gravitational waves increases with a decreasing radius of collapsed object much faster than a gravitational force itself. Gravitationally unstable matter of the Universe will be completely converted into gravitational radiation during the Big Crunch. According to Misner, Thorne & Wheeler (Gravitation, 1977, p.959) plane gravitational waves have not gravitational mass or spacetime is flat everywhere outside the pulse. We can propose that the gravitational mass of the Universe is vanished after converting matter into gravitational waves. This hypothesis in the framework of Einstein's theory of gravitation can solve the problem of singularity without contradiction with theorems by Penrose-Hawking; explain the acceleration of our Universe as the effect of a retarded gravitational potential (Gorkavyi, BAAS, 2003, 35, #3) and the low quadrupole in fluctuations in CMB as result of blue-shift effect in a gravitational field. Proposed solution of dark energy problem free from coincidence problems. The hypothesis keeps best parts of Big Bang theory and inflation model without any unknown physical fields or new dimensions. According to this hypothesis a relic sea of high-frequency gravitational radiation in our Universe can be very dense. Interaction of relic gravitational waves with gravitational fields of galaxies and stars can create an additional dynamical effects like pressure of relic radiation that proportional to gravitational potential GM/(Rc2). This effect can be responsible for dark matter phenomena in galaxies and the Pioneer acceleration in the solar system (Gorkavyi, BAAS, 2005, 37, #2).

  18. Urban tree effects on fine particulate matter and human health

    Treesearch

    David J. Nowak

    2014-01-01

    Overall, city trees reduce particulate matter and provide substantial health benefits; but under certain conditions, they can locally increase particulate matter concentrations. Urban foresters need to understand how trees affect particulate matter so they can select proper species and create appropriate designs to improve air quality. This article details trees'...

  19. Reconstruction of in-plane strain maps using hybrid dense sensor network composed of sensing skin

    NASA Astrophysics Data System (ADS)

    Downey, Austin; Laflamme, Simon; Ubertini, Filippo

    2016-12-01

    The authors have recently developed a soft-elastomeric capacitive (SEC)-based thin film sensor for monitoring strain on mesosurfaces. Arranged in a network configuration, the sensing system is analogous to a biological skin, where local strain can be monitored over a global area. Under plane stress conditions, the sensor output contains the additive measurement of the two principal strain components over the monitored surface. In applications where the evaluation of strain maps is useful, in structural health monitoring for instance, such signal must be decomposed into linear strain components along orthogonal directions. Previous work has led to an algorithm that enabled such decomposition by leveraging a dense sensor network configuration with the addition of assumed boundary conditions. Here, we significantly improve the algorithm’s accuracy by leveraging mature off-the-shelf solutions to create a hybrid dense sensor network (HDSN) to improve on the boundary condition assumptions. The system’s boundary conditions are enforced using unidirectional RSGs and assumed virtual sensors. Results from an extensive experimental investigation demonstrate the good performance of the proposed algorithm and its robustness with respect to sensors’ layout. Overall, the proposed algorithm is seen to effectively leverage the advantages of a hybrid dense network for application of the thin film sensor to reconstruct surface strain fields over large surfaces.

  20. Accelerated craniofacial bone regeneration through dense collagen gel scaffolds seeded with dental pulp stem cells

    NASA Astrophysics Data System (ADS)

    Chamieh, Frédéric; Collignon, Anne-Margaux; Coyac, Benjamin R.; Lesieur, Julie; Ribes, Sandy; Sadoine, Jérémy; Llorens, Annie; Nicoletti, Antonino; Letourneur, Didier; Colombier, Marie-Laure; Nazhat, Showan N.; Bouchard, Philippe; Chaussain, Catherine; Rochefort, Gael Y.

    2016-12-01

    Therapies using mesenchymal stem cell (MSC) seeded scaffolds may be applicable to various fields of regenerative medicine, including craniomaxillofacial surgery. Plastic compression of collagen scaffolds seeded with MSC has been shown to enhance the osteogenic differentiation of MSC as it increases the collagen fibrillary density. The aim of the present study was to evaluate the osteogenic effects of dense collagen gel scaffolds seeded with mesenchymal dental pulp stem cells (DPSC) on bone regeneration in a rat critical-size calvarial defect model. Two symmetrical full-thickness defects were created (5 mm diameter) and filled with either a rat DPSC-containing dense collagen gel scaffold (n = 15), or an acellular scaffold (n = 15). Animals were imaged in vivo by microcomputer tomography (Micro-CT) once a week during 5 weeks, whereas some animals were sacrificed each week for histology and histomorphometry analysis. Bone mineral density and bone micro-architectural parameters were significantly increased when DPSC-seeded scaffolds were used. Histological and histomorphometrical data also revealed significant increases in fibrous connective and mineralized tissue volume when DPSC-seeded scaffolds were used, associated with expression of type I collagen, osteoblast-associated alkaline phosphatase and osteoclastic-related tartrate-resistant acid phosphatase. Results demonstrate the potential of DPSC-loaded-dense collagen gel scaffolds to benefit of bone healing process.

  1. Education Matters, August 2011

    ERIC Educational Resources Information Center

    Beckner, Gary, Ed.

    2011-01-01

    "Education Matters" is the monthly newsletter of the Association of American Educators (AAE), an organization dedicated to advancing the American teaching profession through personal growth, professional development, teacher advocacy and protection. This issue of the newsletter includes: (1) Creating New Paths, Attracting New Teachers: Why…

  2. Studies Of Infrasonic Propagation Using Dense Seismic Networks

    NASA Astrophysics Data System (ADS)

    Hedlin, M. A.; deGroot-Hedlin, C. D.; Drob, D. P.

    2011-12-01

    Although there are approximately 100 infrasonic arrays worldwide, more than ever before, the station density is still insufficient to provide validation for detailed propagation modeling. Relatively large infrasonic signals can be observed on seismic channels due to coupling at the Earth's surface. Recent research, using data from the 70-km spaced 400-station USArray and other seismic network deployments, has shown the value of dense seismic network data for filling in the gaps between infrasonic arrays. The dense sampling of the infrasonic wavefield has allowed us to observe complete travel-time branches of infrasound and address important research problems in infrasonic propagation. We present our analysis of infrasound created by a series of rocket motor detonations that occurred at the UTTR facility in Utah in 2007. These data were well recorded by the USArray seismometers. We use the precisely located blasts to assess the utility of G2S mesoscale models and methods to synthesize infrasonic propagation. We model the travel times of the branches using a ray-based approach and the complete wavefield using a FDTD algorithm. Although results from both rays and FDTD approaches predict the travel times to within several seconds, only about 40% of signals are predicted using rays largely due to penetration of sound into shadow zones. FDTD predicts some sound penetration into the shadow zone, but the observed shadow zones, as defined by the seismic data, have considerably narrower spatial extent than either method predicts, perhaps due to un-modeled small-scale structure in the atmosphere.

  3. The thermodynamics of dense granular flow and jamming

    NASA Astrophysics Data System (ADS)

    Lu, Shih Yu

    The scope of the thesis is to propose, based on experimental evidence and theoretical validation, a quantifiable connection between systems that exhibit the jamming phenomenon. When jammed, some materials that flow are able to resist deformation so that they appear solid-like on the laboratory scale. But unlike ordinary fusion, which has a critically defined criterion in pressure and temperature, jamming occurs under a wide range of conditions. These condition have been rigorously investigated but at the moment, no self-consistent framework can apply to grains, foam and colloids that may have suddenly ceased to flow. To quantify the jamming behavior, a constitutive model of dense granular flows is deduced from shear-flow experiments. The empirical equations are then generalized, via a thermodynamic approach, into an equation-of-state for jamming. Notably, the unifying theory also predicts the experimental data on the behavior of molecular glassy liquids. This analogy paves a crucial road map for a unifying theoretical framework in condensed matter, for example, ranging from sand to fire retardants to toothpaste.

  4. Repair of dense connective tissues via biomaterial-mediated matrix reprogramming of the wound interface.

    PubMed

    Qu, Feini; Pintauro, Michael P; Haughan, Joanne E; Henning, Elizabeth A; Esterhai, John L; Schaer, Thomas P; Mauck, Robert L; Fisher, Matthew B

    2015-01-01

    Repair of dense connective tissues in adults is limited by their intrinsic hypocellularity and is exacerbated by a dense extracellular matrix (ECM) that impedes cellular migration to and local proliferation at the wound site. Conversely, healing in fetal tissues occurs due in part to an environment conducive to cell mobility and division. Here, we investigated whether the application of a degradative enzyme, collagenase, could reprogram the adult wound margin to a more fetal-like state, and thus abrogate the biophysical impediments that hinder migration and proliferation. We tested this concept using the knee meniscus, a commonly injured structure for which few regenerative approaches exist. To focus delivery and degradation to the wound interface, we developed a system in which collagenase was stored inside poly(ethylene oxide) (PEO) electrospun nanofibers and released upon hydration. Through a series of in vitro and in vivo studies, our findings show that partial digestion of the wound interface improves repair by creating a more compliant and porous microenvironment that expedites cell migration to and/or proliferation at the wound margin. This innovative approach of targeted manipulation of the wound interface, focused on removing the naturally occurring barriers to adult tissue repair, may find widespread application in the treatment of injuries to a variety of dense connective tissues. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Dense Deposit Disease Mimicking a Renal Small Vessel Vasculitis

    PubMed Central

    Singh, Lavleen; Bhardwaj, Swati; Sinha, Aditi; Bagga, Arvind; Dinda, Amit

    2016-01-01

    Dense deposit disease is caused by fluid-phase dysregulation of the alternative complement pathway and frequently deviates from the classic membranoproliferative pattern of injury on light microscopy. Other patterns of injury described for dense deposit disease include mesangioproliferative, acute proliferative/exudative, and crescentic GN. Regardless of the histologic pattern, C3 glomerulopathy, which includes dense deposit disease and C3 GN, is defined by immunofluorescence intensity of C3c two or more orders of magnitude greater than any other immune reactant (on a 0–3 scale). Ultrastructural appearances distinguish dense deposit disease and C3 GN. Focal and segmental necrotizing glomerular lesions with crescents, mimicking a small vessel vasculitis such as ANCA-associated GN, are a very rare manifestation of dense deposit disease. We describe our experience with this unusual histologic presentation and distinct clinical course of dense deposit disease, discuss the pitfalls in diagnosis, examine differential diagnoses, and review the relevant literature. PMID:26361799

  6. Recognizing Axionic Dark Matter by Compton and de Broglie Scale Modulation of Pulsar Timing.

    PubMed

    De Martino, Ivan; Broadhurst, Tom; Tye, S-H Henry; Chiueh, Tzihong; Schive, Hsi-Yu; Lazkoz, Ruth

    2017-12-01

    Light axionic dark matter, motivated by string theory, is increasingly favored for the "no weakly interacting massive particle era". Galaxy formation is suppressed below a Jeans scale of ≃10^{8}  M_{⊙} by setting the axion mass to m_{B}∼10^{-22}  eV, and the large dark cores of dwarf galaxies are explained as solitons on the de Broglie scale. This is persuasive, but detection of the inherent scalar field oscillation at the Compton frequency ω_{B}=(2.5  months)^{-1}(m_{B}/10^{-22}  eV) would be definitive. By evolving the coupled Schrödinger-Poisson equation for a Bose-Einstein condensate, we predict the dark matter is fully modulated by de Broglie interference, with a dense soliton core of size ≃150  pc, at the Galactic center. The oscillating field pressure induces general relativistic time dilation in proportion to the local dark matter density and pulsars within this dense core have detectably large timing residuals of ≃400  nsec/(m_{B}/10^{-22}  eV). This is encouraging as many new pulsars should be discovered near the Galactic center with planned radio surveys. More generally, over the whole Galaxy, differences in dark matter density between pairs of pulsars imprints a pairwise Galactocentric signature that can be distinguished from an isotropic gravitational wave background.

  7. Potential of phase contrast x-ray imaging for detecting tumors in dense breast: initial phantom studies

    NASA Astrophysics Data System (ADS)

    Omoumi, Farid H.; Wu, Di; Guo, Yuran; Ghani, Muhammad U.; Li, Yuhua; Boyce, Kari E.; Liu, Hong

    2018-02-01

    The objective of this study is to demonstrate the potential of using the High-energy in-line phase contrast x-ray imaging to detect lesions that are indistinguishable by conventional x-ray mammography but are detectable by supplemental ultrasound screening within dense breasts. For this study, a custom-made prototype x-ray/ultrasound dualmodality phantom that mimics dense breast is created to include embedded carbon fiber disks with multiple diameters and thicknesses. The phase contrast image is acquired using a prototype at 120kVp, 67μA, exposure time of 16.7sec and focal spot size of 18.3μm with average glandular dose (AGD) of 0.3mGy under a geometric magnification of 2.48. The conventional x-ray image is acquired with a bench top system operating at 40kVp, 300μA, exposure time of 50sec and same AGD. The results demonstrate that conventional x-ray imaging is unable to detect any of the carbon fiber disks, while phase contrast imaging and ultrasonography are able to detect most or all of the disks under the applied experimental conditions. These results illustrate phase contrast imaging is capable of detecting targets in a dual-modality phantom which simulates lesions in dense breast tissue, when the simulated lesions are not distinguishable by conventional mammography. Therefore mammographic screening with phase contrast technique could eventually replace both x-ray and ultrasonography for screening detection of small lesions with microcalcification in dense breasts where pathologic lesions are masked due to highly glandular tissue. These results encourage further investigation using high glandular density phantoms to further evaluate the effectiveness of phase contrast imaging as a single modality test, which combines the advantages of both x-ray and ultrasound imaging in cancer screening of patients with dense breasts.

  8. Dense Regions in Supersonic Isothermal Turbulence

    NASA Astrophysics Data System (ADS)

    Robertson, Brant; Goldreich, Peter

    2018-02-01

    The properties of supersonic isothermal turbulence influence a variety of astrophysical phenomena, including the structure and evolution of star-forming clouds. This work presents a simple model for the structure of dense regions in turbulence in which the density distribution behind isothermal shocks originates from rough hydrostatic balance between the pressure gradient behind the shock and its deceleration from ram pressure applied by the background fluid. Using simulations of supersonic isothermal turbulence and idealized waves moving through a background medium, we show that the structural properties of dense, shocked regions broadly agree with our analytical model. Our work provides a new conceptual picture for describing the dense regions, which complements theoretical efforts to understand the bulk statistical properties of turbulence and attempts to model the more complex features of star-forming clouds like magnetic fields, self-gravity, or radiative properties.

  9. Self-diffusion in dense granular shear flows.

    PubMed

    Utter, Brian; Behringer, R P

    2004-03-01

    Diffusivity is a key quantity in describing velocity fluctuations in granular materials. These fluctuations are the basis of many thermodynamic and hydrodynamic models which aim to provide a statistical description of granular systems. We present experimental results on diffusivity in dense, granular shear flows in a two-dimensional Couette geometry. We find that self-diffusivities D are proportional to the local shear rate gamma; with diffusivities along the direction of the mean flow approximately twice as large as those in the perpendicular direction. The magnitude of the diffusivity is D approximately gamma;a(2), where a is the particle radius. However, the gradient in shear rate, coupling to the mean flow, and strong drag at the moving boundary lead to particle displacements that can appear subdiffusive or superdiffusive. In particular, diffusion appears to be superdiffusive along the mean flow direction due to Taylor dispersion effects and subdiffusive along the perpendicular direction due to the gradient in shear rate. The anisotropic force network leads to an additional anisotropy in the diffusivity that is a property of dense systems and has no obvious analog in rapid flows. Specifically, the diffusivity is suppressed along the direction of the strong force network. A simple random walk simulation reproduces the key features of the data, such as the apparent superdiffusive and subdiffusive behavior arising from the mean velocity field, confirming the underlying diffusive motion. The additional anisotropy is not observed in the simulation since the strong force network is not included. Examples of correlated motion, such as transient vortices, and Lévy flights are also observed. Although correlated motion creates velocity fields which are qualitatively different from collisional Brownian motion and can introduce nondiffusive effects, on average the system appears simply diffusive.

  10. Enlightening Students about Dark Matter

    NASA Astrophysics Data System (ADS)

    Hamilton, Kathleen; Barr, Alex; Eidelman, Dave

    2018-01-01

    Dark matter pervades the universe. While it is invisible to us, we can detect its influence on matter we can see. To illuminate this concept, we have created an interactive javascript program illustrating predictions made by six different models for dark matter distributions in galaxies. Students are able to match the predicted data with actual experimental results, drawn from several astronomy papers discussing dark matter’s impact on galactic rotation curves. Programming each new model requires integration of density equations with parameters determined by nonlinear curve-fitting using MATLAB scripts we developed. Using our javascript simulation, students can determine the most plausible dark matter models as well as the average percentage of dark matter lurking in galaxies, areas where the scientific community is still continuing to research. In that light, we strive to use the most up-to-date and accepted concepts: two of our dark matter models are the pseudo-isothermal halo and Navarro-Frenk-White, and we integrate out to each galaxy’s virial radius. Currently, our simulation includes NGC3198, NGC2403, and our own Milky Way.

  11. Bulgeless dwarf galaxies and dark matter cores from supernova-driven outflows.

    PubMed

    Governato, F; Brook, C; Mayer, L; Brooks, A; Rhee, G; Wadsley, J; Jonsson, P; Willman, B; Stinson, G; Quinn, T; Madau, P

    2010-01-14

    For almost two decades the properties of 'dwarf' galaxies have challenged the cold dark matter (CDM) model of galaxy formation. Most observed dwarf galaxies consist of a rotating stellar disk embedded in a massive dark-matter halo with a near-constant-density core. Models based on the dominance of CDM, however, invariably form galaxies with dense spheroidal stellar bulges and steep central dark-matter profiles, because low-angular-momentum baryons and dark matter sink to the centres of galaxies through accretion and repeated mergers. Processes that decrease the central density of CDM halos have been identified, but have not yet reconciled theory with observations of present-day dwarfs. This failure is potentially catastrophic for the CDM model, possibly requiring a different dark-matter particle candidate. Here we report hydrodynamical simulations (in a framework assuming the presence of CDM and a cosmological constant) in which the inhomogeneous interstellar medium is resolved. Strong outflows from supernovae remove low-angular-momentum gas, which inhibits the formation of bulges and decreases the dark-matter density to less than half of what it would otherwise be within the central kiloparsec. The analogues of dwarf galaxies-bulgeless and with shallow central dark-matter profiles-arise naturally in these simulations.

  12. The white matter query language: a novel approach for describing human white matter anatomy

    PubMed Central

    Makris, Nikos; Rathi, Yogesh; Shenton, Martha; Kikinis, Ron; Kubicki, Marek; Westin, Carl-Fredrik

    2016-01-01

    We have developed a novel method to describe human white matter anatomy using an approach that is both intuitive and simple to use, and which automatically extracts white matter tracts from diffusion MRI volumes. Further, our method simplifies the quantification and statistical analysis of white matter tracts on large diffusion MRI databases. This work reflects the careful syntactical definition of major white matter fiber tracts in the human brain based on a neuroanatomist’s expert knowledge. The framework is based on a novel query language with a near-to-English textual syntax. This query language makes it possible to construct a dictionary of anatomical definitions that describe white matter tracts. The definitions include adjacent gray and white matter regions, and rules for spatial relations. This novel method makes it possible to automatically label white matter anatomy across subjects. After describing this method, we provide an example of its implementation where we encode anatomical knowledge in human white matter for ten association and 15 projection tracts per hemisphere, along with seven commissural tracts. Importantly, this novel method is comparable in accuracy to manual labeling. Finally, we present results applying this method to create a white matter atlas from 77 healthy subjects, and we use this atlas in a small proof-of-concept study to detect changes in association tracts that characterize schizophrenia. PMID:26754839

  13. The white matter query language: a novel approach for describing human white matter anatomy.

    PubMed

    Wassermann, Demian; Makris, Nikos; Rathi, Yogesh; Shenton, Martha; Kikinis, Ron; Kubicki, Marek; Westin, Carl-Fredrik

    2016-12-01

    We have developed a novel method to describe human white matter anatomy using an approach that is both intuitive and simple to use, and which automatically extracts white matter tracts from diffusion MRI volumes. Further, our method simplifies the quantification and statistical analysis of white matter tracts on large diffusion MRI databases. This work reflects the careful syntactical definition of major white matter fiber tracts in the human brain based on a neuroanatomist's expert knowledge. The framework is based on a novel query language with a near-to-English textual syntax. This query language makes it possible to construct a dictionary of anatomical definitions that describe white matter tracts. The definitions include adjacent gray and white matter regions, and rules for spatial relations. This novel method makes it possible to automatically label white matter anatomy across subjects. After describing this method, we provide an example of its implementation where we encode anatomical knowledge in human white matter for ten association and 15 projection tracts per hemisphere, along with seven commissural tracts. Importantly, this novel method is comparable in accuracy to manual labeling. Finally, we present results applying this method to create a white matter atlas from 77 healthy subjects, and we use this atlas in a small proof-of-concept study to detect changes in association tracts that characterize schizophrenia.

  14. Dark Matter Hairs Around Jupiter

    NASA Image and Video Library

    2015-11-23

    This illustration shows Jupiter surrounded by filaments of dark matter called "hairs," which are proposed in a study in the Astrophysical Journal by Gary Prézeau of NASA's Jet Propulsion Laboratory, Pasadena, California. A hair is created when a stream of dark matter particles goes through the planet. According to simulations, the hair is densest at a point called the "root." When particles of a dark matter stream pass through the core of Jupiter, they form a hair whose root has a particle density about a trillion times greater than average. The size of Jupiter relative to the distance between Jupiter and the hair roots is to scale. http://photojournal.jpl.nasa.gov/catalog/PIA20178

  15. Inertial quantum sensors using light and matter

    NASA Astrophysics Data System (ADS)

    Barrett, B.; Bertoldi, A.; Bouyer, P.

    2016-05-01

    The past few decades have seen dramatic progress in our ability to manipulate and coherently control matter-waves. Although the duality between particles and waves has been well tested since de Broglie introduced the matter-wave analog of the optical wavelength in 1924, manipulating atoms with a level of coherence that enables one to use these properties for precision measurements has only become possible with our ability to produce atomic samples exhibiting temperatures of only a few millionths of a degree above absolute zero. Since the initial experiments a few decades ago, the field of atom optics has developed in many ways, with both fundamental and applied significance. The exquisite control of matter waves offers the prospect of a new generation of force sensors exhibiting unprecedented sensitivity and accuracy, for applications from navigation and geophysics to tests of general relativity. Thanks to the latest developments in this field, the first commercial products using this quantum technology are now available. In the future, our ability to create large coherent ensembles of atoms will allow us an even more precise control of the matter-wave and the ability to create highly entangled states for non-classical atom interferometry.

  16. The Dark Matter of Biology.

    PubMed

    Ross, Jennifer L

    2016-09-06

    The inside of the cell is full of important, yet invisible species of molecules and proteins that interact weakly but couple together to have huge and important effects in many biological processes. Such "dark matter" inside cells remains mostly hidden, because our tools were developed to investigate strongly interacting species and folded proteins. Example dark-matter species include intrinsically disordered proteins, posttranslational states, ion species, and rare, transient, and weak interactions undetectable by biochemical assays. The dark matter of biology is likely to have multiple, vital roles to regulate signaling, rates of reactions, water structure and viscosity, crowding, and other cellular activities. We need to create new tools to image, detect, and understand these dark-matter species if we are to truly understand fundamental physical principles of biology. Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  17. Dense Suspension Splash

    NASA Astrophysics Data System (ADS)

    Zhang, Wendy; Dodge, Kevin M.; Peters, Ivo R.; Ellowitz, Jake; Klein Schaarsberg, Martin H.; Jaeger, Heinrich M.

    2014-03-01

    Upon impact onto a solid surface at several meters-per-second, a dense suspension plug splashes by ejecting liquid-coated particles. We study the mechanism for splash formation using experiments and a numerical model. In the model, the dense suspension is idealized as a collection of cohesionless, rigid grains with finite surface roughness. The grains also experience lubrication drag as they approach, collide inelastically and rebound away from each other. Simulations using this model reproduce the measured momentum distribution of ejected particles. They also provide direct evidence supporting the conclusion from earlier experiments that inelastic collisions, rather than viscous drag, dominate when the suspension contains macroscopic particles immersed in a low-viscosity solvent such as water. Finally, the simulations reveal two distinct routes for splash formation: a particle can be ejected by a single high momentum-change collision. More surprisingly, a succession of small momentum-change collisions can accumulate to eject a particle outwards. Supported by NSF through its MRSEC program (DMR-0820054) and fluid dynamics program (CBET-1336489).

  18. Topology of genetic associations between regional gray matter volume and intellectual ability: Evidence for a high capacity network.

    PubMed

    Bohlken, Marc M; Brouwer, Rachel M; Mandl, René C W; Hedman, Anna M; van den Heuvel, Martijn P; van Haren, Neeltje E M; Kahn, René S; Hulshoff Pol, Hilleke E

    2016-01-01

    Intelligence is associated with a network of distributed gray matter areas including the frontal and parietal higher association cortices and primary processing areas of the temporal and occipital lobes. Efficient information transfer between gray matter regions implicated in intelligence is thought to be critical for this trait to emerge. Genetic factors implicated in intelligence and gray matter may promote a high capacity for information transfer. Whether these genetic factors act globally or on local gray matter areas separately is not known. Brain maps of phenotypic and genetic associations between gray matter volume and intelligence were made using structural equation modeling of 3T MRI T1-weighted scans acquired in 167 adult twins of the newly acquired U-TWIN cohort. Subsequently, structural connectivity analyses (DTI) were performed to test the hypothesis that gray matter regions associated with intellectual ability form a densely connected core. Gray matter regions associated with intellectual ability were situated in the right prefrontal, bilateral temporal, bilateral parietal, right occipital and subcortical regions. Regions implicated in intelligence had high structural connectivity density compared to 10,000 reference networks (p=0.031). The genetic association with intelligence was for 39% explained by a genetic source unique to these regions (independent of total brain volume), this source specifically implicated the right supramarginal gyrus. Using a twin design, we show that intelligence is genetically represented in a spatially distributed and densely connected network of gray matter regions providing a high capacity infrastructure. Although genes for intelligence have overlap with those for total brain volume, we present evidence that there are genes for intelligence that act specifically on the subset of brain areas that form an efficient brain network. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Cold dark matter. 2: Spatial and velocity statistics

    NASA Technical Reports Server (NTRS)

    Gelb, James M.; Bertschinger, Edmund

    1994-01-01

    We examine high-resolution gravitational N-body simulations of the omega = 1 cold dark matter (CDM) model in order to determine whether there is any normalization of the initial density fluctuation spectrum that yields acceptable results for galaxy clustering and velocities. Dense dark matter halos in the evolved mass distribution are identified with luminous galaxies; the most massive halos are also considered as sites for galaxy groups, with a range of possibilities explored for the group mass-to-light ratios. We verify the earlier conclusions of White et al. (1987) for the low-amplitude (high-bias) CDM model-the galaxy correlation function is marginally acceptable but that there are too many galaxies. We also show that the peak biasing method does not accurately reproduce the results obtained using dense halos identified in the simulations themselves. The Cosmic Background Explorer (COBE) anisotropy implies a higher normalization, resulting in problems with excessive pairwise galaxy velocity dispersion unless a strong velocity bias is present. Although we confirm the strong velocity bias of halos reported by Couchman & Carlberg (1992), we show that the galaxy motions are still too large on small scales. We find no amplitude for which the CDM model can reconcile simultaneously and galaxy correlation function, the low pairwise velocity dispersion, and the richness distribution of groups and clusters. With the normalization implied by COBE, the CDM spectrum has too much power on small scales if omega = 1.

  20. Accelerated craniofacial bone regeneration through dense collagen gel scaffolds seeded with dental pulp stem cells

    PubMed Central

    Chamieh, Frédéric; Collignon, Anne-Margaux; Coyac, Benjamin R.; Lesieur, Julie; Ribes, Sandy; Sadoine, Jérémy; Llorens, Annie; Nicoletti, Antonino; Letourneur, Didier; Colombier, Marie-Laure; Nazhat, Showan N.; Bouchard, Philippe; Chaussain, Catherine; Rochefort, Gael Y.

    2016-01-01

    Therapies using mesenchymal stem cell (MSC) seeded scaffolds may be applicable to various fields of regenerative medicine, including craniomaxillofacial surgery. Plastic compression of collagen scaffolds seeded with MSC has been shown to enhance the osteogenic differentiation of MSC as it increases the collagen fibrillary density. The aim of the present study was to evaluate the osteogenic effects of dense collagen gel scaffolds seeded with mesenchymal dental pulp stem cells (DPSC) on bone regeneration in a rat critical-size calvarial defect model. Two symmetrical full-thickness defects were created (5 mm diameter) and filled with either a rat DPSC-containing dense collagen gel scaffold (n = 15), or an acellular scaffold (n = 15). Animals were imaged in vivo by microcomputer tomography (Micro-CT) once a week during 5 weeks, whereas some animals were sacrificed each week for histology and histomorphometry analysis. Bone mineral density and bone micro-architectural parameters were significantly increased when DPSC-seeded scaffolds were used. Histological and histomorphometrical data also revealed significant increases in fibrous connective and mineralized tissue volume when DPSC-seeded scaffolds were used, associated with expression of type I collagen, osteoblast-associated alkaline phosphatase and osteoclastic-related tartrate-resistant acid phosphatase. Results demonstrate the potential of DPSC-loaded-dense collagen gel scaffolds to benefit of bone healing process. PMID:27934940

  1. The dark-matter axion mass

    NASA Astrophysics Data System (ADS)

    Klaer, Vincent B.; Moore, Guy D.

    2017-11-01

    We evaluate the efficiency of axion production from spatially random initial conditions in the axion field, so a network of axionic strings is present. For the first time, we perform numerical simulations which fully account for the large short-distance contributions to the axionic string tension, and the resulting dense network of high-tension axionic strings. We find nevertheless that the total axion production is somewhat less efficient than in the angle-averaged misalignment case. Combining our results with a recent determination of the hot QCD topological susceptibility [1], we find that if the axion makes up all of the dark matter, then the axion mass is ma = 26.2 ± 3.4 μeV.

  2. Experimental soft-matter science

    NASA Astrophysics Data System (ADS)

    Nagel, Sidney R.

    2017-04-01

    Soft materials consist of basic units that are significantly larger than an atom but much smaller than the overall dimensions of the sample. The label "soft condensed matter" emphasizes that the large basic building blocks of these materials produce low elastic moduli that govern a material's ability to withstand deformations. Aside from softness, there are many other properties that are also caused by the large size of the constituent building blocks. Soft matter is dissipative, disordered, far from equilibrium, nonlinear, thermal and entropic, slow, observable, gravity affected, patterned, nonlocal, interfacially elastic, memory forming, and active. This is only a partial list of how matter created from large component particles is distinct from "hard matter" composed of constituents at an atomic scale. Issues inherent in soft matter raise problems that are broadly important in diverse areas of science and require multiple modes of attack. For example, far-from-equilibrium behavior is confronted in biology, chemistry, geophysics, astrophysics, and nuclear physics. Similarly, issues dealing with disorder appear broadly throughout many branches of inquiry wherever rugged landscapes are invoked. This article reviews the discussions that occurred during a workshop held on 30-31 January 2016 in which opportunities in soft-matter experiment were surveyed. Soft matter has had an exciting history of discovery and continues to be a fertile ground for future research.

  3. Hypothalamic tumors impact gray and white matter volumes in fronto-limbic brain areas.

    PubMed

    Özyurt, Jale; Müller, Hermann L; Warmuth-Metz, Monika; Thiel, Christiane M

    2017-04-01

    Patients with hypothalamic involvement of a sellar/parasellar tumor often suffer from cognitive and social-emotional deficits that a lesion in the hypothalamus cannot fully explain. It is conceivable that these deficits are partly due to distal changes in hypothalamic networks, evolving secondary to a focal lesion. Focusing on childhood-onset craniopharyngioma patients, we aimed at investigating the impact of hypothalamic lesions on gray and white matter areas densely connected to the hypothalamus, and to relate structural changes to neuropsychological deficits frequently observed in patients. We performed a voxel-based morphometric analysis based on data of 11 childhood-onset craniopharyngioma patients with hypothalamic tumor involvement, and 18 healthy controls (median age: 17.2 and 17.4 yrs.). Whole-brain analyses were used to test for volumetric differences between the groups (T-tests) and subsequent regression analyses were used to correlate neuropsychological performance with gray and white matter volumes within the patient group. Patients compared to controls had significantly reduced gray matter volumes in areas of the anterior and posterior limbic subsystems which are densely connected with the hypothalamus. In addition, a reduction in white matter volumes was observed in tracts connecting the hypothalamus to other limbic areas. Worse long-term memory retrieval was correlated with smaller gray matter volumes in the posterior cingulate cortex. Our data provide the first evidence that hypothalamic tumor involvement impacts gray and white matter volumes in limbic areas, outside the area of tumor growth. Notably, the functional range of the two limbic subsystems affected, strikingly parallels the two major domains of psychological complaints in patients i.e., deficits in episodic memory and in socio-emotional functioning. We suggest that focal hypothalamic lesions may trigger distal changes in connected brain areas, which then contribute to the impairments in

  4. Prediction of a Densely Loaded Particle-Laden Jet using a Euler-Lagrange Dense Spray Model

    NASA Astrophysics Data System (ADS)

    Pakseresht, Pedram; Apte, Sourabh V.

    2017-11-01

    Modeling of a dense spray regime using an Euler-Lagrange discrete-element approach is challenging because of local high volume loading. A subgrid cluster of droplets can lead to locally high void fractions for the disperse phase. Under these conditions, spatio-temporal changes in the carrier phase volume fractions, which are commonly neglected in spray simulations in an Euler-Lagrange two-way coupling model, could become important. Accounting for the carrier phase volume fraction variations, leads to zero-Mach number, variable density governing equations. Using pressure-based solvers, this gives rise to a source term in the pressure Poisson equation and a non-divergence free velocity field. To test the validity and predictive capability of such an approach, a round jet laden with solid particles is investigated using Direct Numerical Simulation and compared with available experimental data for different loadings. Various volume fractions spanning from dilute to dense regimes are investigated with and without taking into account the volume displacement effects. The predictions of the two approaches are compared and analyzed to investigate the effectiveness of the dense spray model. Financial support was provided by National Aeronautics and Space Administration (NASA).

  5. Direct detection of MeV-scale dark matter utilizing germanium internal amplification for the charge created by the ionization of impurities

    NASA Astrophysics Data System (ADS)

    Mei, D.-M.; Wang, G.-J.; Mei, H.; Yang, G.; Liu, J.; Wagner, M.; Panth, R.; Kooi, K.; Yang, Y.-Y.; Wei, W.-Z.

    2018-03-01

    Light, MeV-scale dark matter (DM) is an exciting DM candidate that is undetectable by current experiments. A germanium (Ge) detector utilizing internal charge amplification for the charge carriers created by the ionization of impurities is a promising new technology with experimental sensitivity for detecting MeV-scale DM. We analyze the physics mechanisms of the signal formation, charge creation, charge internal amplification, and the projected sensitivity for directly detecting MeV-scale DM particles. We present a design for a novel Ge detector at helium temperature (˜ 4 K) enabling ionization of impurities from DM impacts. With large localized E-fields, the ionized excitations can be accelerated to kinetic energies larger than the Ge bandgap at which point they can create additional electron-hole pairs, producing intrinsic amplification to achieve an ultra-low energy threshold of ˜ 0.1 eV for detecting low-mass DM particles in the MeV scale. Correspondingly, such a Ge detector with 1 kg-year exposure will have high sensitivity to a DM-nucleon cross section of ˜ 5 × 10^{-45} cm2 at a DM mass of ˜ 10 MeV/c2 and a DM-electron cross section of ˜ 5 × 10^{-46} cm2 at a DM mass of ˜ 1 MeV/c^2.

  6. Weak synchronization and large-scale collective oscillation in dense bacterial suspensions

    NASA Astrophysics Data System (ADS)

    Wu, Yilin

    Collective oscillatory behavior is ubiquitous in nature and it plays a vital role in many biological processes. Collective oscillations in biological multicellular systems often arise from coupling mediated by diffusive chemicals, by electrochemical mechanisms, or by biomechanical interaction between cells and their physical environment. In these examples, the phase of some oscillatory intracellular degree of freedom is synchronized. Here, in contrast, we discovered a unique 'weak synchronization' mechanism that does not require long-range coupling, nor even inherent oscillation of individual cells: We found that millions of motile cells in dense bacterial suspensions can self-organize into highly robust collective oscillatory motion, while individuals move in an erratic manner. Over large spatial scales we found that the phase of the oscillations is in fact organized into a centimeter scale traveling wave. We present a model of noisy self-propelled particles with strictly local interactions that accounts faithfully for our observations. These findings expand our knowledge of biological self-organization and reveal a new type of long-range order in active matter systems. The mechanism of collective oscillation uncovered here may inspire new strategies to control the self-organization of active matter and swarming robots. This work is supported by funding from CUHK Direct research Grants (4053019, 4053079, 4053130), the Research Grants Council of HKSAR (RGC Ref. No. CUHK 409713), and from the National Natural Science Foundation of China (NSFC 21473152).

  7. The influence of algal organic matter produced by Microcystis aeruginosa on coagulation-ultrafiltration treatment of natural organic matter.

    PubMed

    Xu, Jie; Zhao, Yanxia; Gao, Baoyu; Han, Songlin; Zhao, Qian; Liu, Xiaoli

    2018-04-01

    Cyanobacterial bloom causes the release of algal organic matter (AOM), which inevitably affects the treatment processes of natural organic matter (NOM). This study works on treating micro-polluted surface water (SW) by emerging coagulant, namely titanium sulfate (Ti(SO 4 ) 2 ), followed by Low Pressure Ultrafiltration (LPUF) technology. In particular, we explored the respective influence of extracellular organic matter (EOM) and intracellular organic matter (IOM) on synergetic EOM-NOM/IOM-NOM removal, functional mechanisms and subsequent filtration performance. Results show that the IOM inclusion in surface water body facilitated synergic IOM-NOM composite pollutants removal by Ti(SO 4 ) 2 , wherein loosely-aggregated flocs were produced, resulting in floc cake layer with rich porosity and permeability during LPUF. On the contrary, the surface water invaded by EOM pollutants increased Ti(SO 4 ) 2 coagulation burden, with substantially deteriorated both UV 254 -represented and dissolved organic matter (DOC) removal. Corresponded with the weak Ti(SO 4 ) 2 coagulation for EOM-NOM removal was the resultant serious membrane fouling during LPUF procedure, wherein dense cake layer was formed due to the compact structure of flocs. Although the IOM enhanced NOM removal with reduced Ti(SO 4 ) 2 dose and yielded mitigated membrane fouling, larger percentage of irreversible fouling was seen than NOM and EOM-NOM cases, which was most likely due to the substances with small molecular weight, such as microcystin, adhering in membrane pores. This research would provide theoretical basis for dose selection and process design during AOM-NOM water treatment. Copyright © 2018 Elsevier Ltd. All rights reserved.

  8. Finding Hierarchical and Overlapping Dense Subgraphs using Nucleus Decompositions

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Seshadhri, Comandur; Pinar, Ali; Sariyuce, Ahmet Erdem

    Finding dense substructures in a graph is a fundamental graph mining operation, with applications in bioinformatics, social networks, and visualization to name a few. Yet most standard formulations of this problem (like clique, quasiclique, k-densest subgraph) are NP-hard. Furthermore, the goal is rarely to nd the \\true optimum", but to identify many (if not all) dense substructures, understand their distribution in the graph, and ideally determine a hierarchical structure among them. Current dense subgraph nding algorithms usually optimize some objective, and only nd a few such subgraphs without providing any hierarchy. It is also not clear how to account formore » overlaps in dense substructures. We de ne the nucleus decomposition of a graph, which represents the graph as a forest of nuclei. Each nucleus is a subgraph where smaller cliques are present in many larger cliques. The forest of nuclei is a hierarchy by containment, where the edge density increases as we proceed towards leaf nuclei. Sibling nuclei can have limited intersections, which allows for discovery of overlapping dense subgraphs. With the right parameters, the nuclear decomposition generalizes the classic notions of k-cores and k-trusses. We give provable e cient algorithms for nuclear decompositions, and empirically evaluate their behavior in a variety of real graphs. The tree of nuclei consistently gives a global, hierarchical snapshot of dense substructures, and outputs dense subgraphs of higher quality than other state-of-theart solutions. Our algorithm can process graphs with tens of millions of edges in less than an hour.« less

  9. Conversion of baryonic fermions into squarks in neutron stars from supersymmetric dark matter Q-balls

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Shoemaker, Ian M.

    2009-08-01

    The gauge-mediated model of supersymmetry breaking implies that stable nontopological solitons, Q-balls, could form in the early Universe and comprise the dark matter. It is shown that the inclusion of the effects from gravity-mediation set an upper limit on the size of Q-balls. When in a dense baryonic environment Q-balls grow until reaching this limiting size at which point they fragment into two equal-sized Q-balls. This Q-splitting process will rapidly destroy a neutron star that absorbs even one Q-ball. The new limits on Q-ball dark matter require an ultralight gravitino m{sub 3/2} < or approx. keV, naturally avoiding the gravitinomore » overclosure problem, and providing the minimal supersymmetric standard model with a dark matter candidate where gravitino dark matter is not viable.« less

  10. Quantum Dense Coding About a Two-Qubit Heisenberg XYZ Model

    NASA Astrophysics Data System (ADS)

    Xu, Hui-Yun; Yang, Guo-Hui

    2017-09-01

    By taking into account the nonuniform magnetic field, the quantum dense coding with thermal entangled states of a two-qubit anisotropic Heisenberg XYZ chain are investigated in detail. We mainly show the different properties about the dense coding capacity ( χ) with the changes of different parameters. It is found that dense coding capacity χ can be enhanced by decreasing the magnetic field B, the degree of inhomogeneity b and temperature T, or increasing the coupling constant along z-axis J z . In addition, we also find χ remains the stable value as the change of the anisotropy of the XY plane Δ in a certain temperature condition. Through studying different parameters effect on χ, it presents that we can properly turn the values of B, b, J z , Δ or adjust the temperature T to obtain a valid dense coding capacity ( χ satisfies χ > 1). Moreover, the temperature plays a key role in adjusting the value of dense coding capacity χ. The valid dense coding capacity could be always obtained in the lower temperature-limit case.

  11. Real-Time Large-Scale Dense Mapping with Surfels

    PubMed Central

    Fu, Xingyin; Zhu, Feng; Wu, Qingxiao; Sun, Yunlei; Lu, Rongrong; Yang, Ruigang

    2018-01-01

    Real-time dense mapping systems have been developed since the birth of consumer RGB-D cameras. Currently, there are two commonly used models in dense mapping systems: truncated signed distance function (TSDF) and surfel. The state-of-the-art dense mapping systems usually work fine with small-sized regions. The generated dense surface may be unsatisfactory around the loop closures when the system tracking drift grows large. In addition, the efficiency of the system with surfel model slows down when the number of the model points in the map becomes large. In this paper, we propose to use two maps in the dense mapping system. The RGB-D images are integrated into a local surfel map. The old surfels that reconstructed in former times and far away from the camera frustum are moved from the local map to the global map. The updated surfels in the local map when every frame arrives are kept bounded. Therefore, in our system, the scene that can be reconstructed is very large, and the frame rate of our system remains high. We detect loop closures and optimize the pose graph to distribute system tracking drift. The positions and normals of the surfels in the map are also corrected using an embedded deformation graph so that they are consistent with the updated poses. In order to deal with large surface deformations, we propose a new method for constructing constraints with system trajectories and loop closure keyframes. The proposed new method stabilizes large-scale surface deformation. Experimental results show that our novel system behaves better than the prior state-of-the-art dense mapping systems. PMID:29747450

  12. Circumstellar Interaction in Supernovae in Dense Environments—An Observational Perspective

    NASA Astrophysics Data System (ADS)

    Chandra, Poonam

    2018-02-01

    In a supernova explosion, the ejecta interacting with the surrounding circumstellar medium (CSM) give rise to variety of radiation. Since CSM is created from the mass loss from the progenitor, it carries footprints of the late time evolution of the star. This is one of the unique ways to get a handle on the nature of the progenitor system. Here, I will focus mainly on the supernovae (SNe) exploding in dense environments, a.k.a. Type IIn SNe. Radio and X-ray emission from this class of SNe have revealed important modifications in their radiation properties, due to the presence of high density CSM. Forward shock dominance in the X-ray emission, internal free-free absorption of the radio emission, episodic or non-steady mass loss rate, and asymmetry in the explosion seem to be common properties of this class of SNe.

  13. Generation of electromagnetic emission during the injection of dense supersonic plasma flows into arched magnetic field

    NASA Astrophysics Data System (ADS)

    Viktorov, Mikhail; Golubev, Sergey; Mansfeld, Dmitry; Vodopyanov, Alexander

    2016-04-01

    Interaction of dense supersonic plasma flows with an inhomogeneous arched magnetic field is one of the key problems in near-Earth and space plasma physics. It can influence on the energetic electron population formation in magnetosphere of the Earth, movement of plasma flows in magnetospheres of planets, energy release during magnetic reconnection, generation of electromagnetic radiation and particle precipitation during solar flares eruption. Laboratory study of this interaction is of big interest to determine the physical mechanisms of processes in space plasmas and their detailed investigation under reproducible conditions. In this work a new experimental approach is suggested to study interaction of supersonic (ion Mach number up to 2.7) dense (up to 1015 cm-3) plasma flows with inhomogeneous magnetic field (an arched magnetic trap with a field strength up to 3.3 T) which opens wide opportunities to model space plasma processes in laboratory conditions. Fully ionized plasma flows with density from 1013 cm-3 to 1015 cm-3 are created by plasma generator on the basis of pulsed vacuum arc discharge. Then plasma is injected in an arched open magnetic trap along or across magnetic field lines. The filling of the arched magnetic trap with dense plasma and further magnetic field lines break by dense plasma flow were experimentally demonstrated. The process of plasma deceleration during the injection of plasma flow across the magnetic field lines was experimentally demonstrated. Pulsed plasma microwave emission at the electron cyclotron frequency range was observed. It was shown that frequency spectrum of plasma emission is determined by position of deceleration region in the magnetic field of the magnetic arc, and is affected by plasma density. Frequency spectrum shifts to higher frequencies with increasing of arc current (plasma density) because the deceleration region of plasma flow moves into higher magnetic field. The observed emission can be related to the

  14. Estimating forest-grassland dynamics using soil phytolith assemblages and δ13C of soil organic matter

    Treesearch

    Becky K. Kerns; Margeret M. Moore; Stephen C. Hart

    2001-01-01

    Our objectives were to examine the relationship between contemporary vegetation and surface soil phytolith assemblages, and use phytoliths and δ13C of soil organic matter (SOM) to explore forest-grassland vegetation dynamics. We established plots within three canopy types (open, old-growth, and dense young pine) with different grass species compositions in a...

  15. Strong and Electroweak Matter 2004

    NASA Astrophysics Data System (ADS)

    Eskola, Kari J.; Kainulainen, Kimmo; Kajantie, Keijo; Rummukainen, Kari

    RHIC experimental summary: the message from pp, d+Au and Au+Au collisions / M. Calderón de la Barca Sánchez -- Hydrodynamic aspects of relativistic heavy ion collisions at RHIC / P. F. Kolb -- Photon emission in a hot QCD plasma / P. Aurenche -- In search of the saturation scale: intrinsic features of the CGC / H. Weigert -- From leading hadron suppression to jet quenching at RHIC and LHC / U. A. Wiedemann -- Lattice simulations with chemical potential / C. Schmidt -- Mesonic correlators in hot QCD / M. Laine -- Thermalization and plasma instabilities / P. Arnold -- Transport coefficients in hot QCD / G. D. Moore -- Classical fields and heavy ion collisions / T. Lappi -- Progress in nonequilibrium quantum field theory II / J. Berges and J. Serreau -- A general effective theory for dense quark matter / P. T. Reuter, Q. Wang and D. H. Rischke -- Thermal leptogenesis / M. Plümacher -- Cold electroweak Baryogenesis / J. Smit -- Proton-nucleus collisions in the color glass condensate framework / J.-P. Blaizot, F. Gelis and R. Venugopalan -- From classical to quantum saturation in the nuclear wavefunction / D. N. Triantafyllopoulos -- Charge correlations in heavy ion collisions / A. Rajantie -- Whitening of the quark-gluon plasma / S. Mrówczyński -- Progress in anisotropic plasma physics / P. Romatschke and M. Strickland -- Deconfinement and chiral symmetry: competing orders / K. Tuominen -- Relation between the chiral and deconfinement phase transitions / Y. Hatta -- Renormalized Polyakov loops, matrix models and the Gross-Witten point / A. Dumitru and J. T. Lenaghan -- The nature of the soft excitation at the critical end point of QCD / A. Jakovác ... [et al.] -- Thermodynamics of the 1+1-dimensional nonlinear sigma model through next-to-leading order in 1/N / H. J. Warringa -- Light quark meson correlations at high temperature / E. Laemann ... [et al.] -- Charmonia at finite momenta in a deconfined plasma / S. Datta ... [et al.] -- QCD thermodynamics: lattice

  16. Two-temperature equilibration in warm dense hydrogen measured with x-ray scattering from the LCLS

    NASA Astrophysics Data System (ADS)

    Fletcher, Luke; High Energy Density Sciences Collaboration

    2017-10-01

    Understanding the properties of warm dense hydrogen plasmas is critical for modeling stellar and planetary interiors, as well as for inertial confinement fusion (ICF) experiments. Of central importance are the electron-ion collision and equilibration times that determine the microscopic properties in a high energy density state. Spectrally and angularly resolved x-ray scattering measurements from fs-laser heated hydrogen have resolved the picosecond evolution and energy relaxation from a two-temperature plasma towards thermodynamic equilibrium in the warm dense matter regime. The interaction of rapidly heated cryogenic hydrogen irradiated by a 400 nm, 5x1017 W/cm2 , 70 fs-laser is visualized with ultra-bright 5.5 kev x-ray pulses from the Linac Coherent Light (LCLS) source in 1 Hz repetition rate pump-probe setting. We demonstrate that the energy relaxation is faster than many classical binary collision theories that use ad hoc cutoff parameters used in the Landau-Spitzer determination of the Coulomb logarithm. This work was supported by the DOE Office of Science, Fusion Energy Science under contract No. SF00515 and supported under FWP 100182 and DOE Office of Basic Energy Sciences, Materials Sciences and Engineering Division, contract DE-AC02-76SF00515.

  17. Astronomical Constraints on Quantum Cold Dark Matter

    NASA Astrophysics Data System (ADS)

    Spivey, Shane; Musielak, Z.; Fry, J.

    2012-01-01

    A model of quantum (`fuzzy') cold dark matter that accounts for both the halo core problem and the missing dwarf galaxies problem, which plague the usual cold dark matter paradigm, is developed. The model requires that a cold dark matter particle has a mass so small that its only allowed physical description is a quantum wave function. Each such particle in a galactic halo is bound to a gravitational potential that is created by luminous matter and by the halo itself, and the resulting wave function is described by a Schrödinger equation. To solve this equation on a galactic scale, we impose astronomical constraints that involve several density profiles used to fit data from simulations of dark matter galactic halos. The solutions to the Schrödinger equation are quantum waves which resemble the density profiles acquired from simulations, and they are used to determine the mass of the cold dark matter particle. The effects of adding certain types of baryonic matter to the halo, such as a dwarf elliptical galaxy or a supermassive black hole, are also discussed.

  18. Measurements of the principal Hugoniots of dense gaseous deuterium-helium mixtures: Combined multi-channel optical pyrometry, velocity interferometry, and streak optical pyrometry measurements

    NASA Astrophysics Data System (ADS)

    Li, Zhi-Guo; Chen, Qi-Feng; Gu, Yun-Jun; Zheng, Jun; Chen, Xiang-Rong

    2016-10-01

    The accurate hydrodynamic description of an event or system that addresses the equations of state, phase transitions, dissociations, ionizations, and compressions, determines how materials respond to a wide range of physical environments. To understand dense matter behavior in extreme conditions requires the continual development of diagnostic methods for accurate measurements of the physical parameters. Here, we present a comprehensive diagnostic technique that comprises optical pyrometry, velocity interferometry, and time-resolved spectroscopy. This technique was applied to shock compression experiments of dense gaseous deuterium-helium mixtures driven via a two-stage light gas gun. The advantage of this approach lies in providing measurements of multiple physical parameters in a single experiment, such as light radiation histories, particle velocity profiles, and time-resolved spectra, which enables simultaneous measurements of shock velocity, particle velocity, pressure, density, and temperature and expands understanding of dense high pressure shock situations. The combination of multiple diagnostics also allows different experimental observables to be measured and cross-checked. Additionally, it implements an accurate measurement of the principal Hugoniots of deuterium-helium mixtures, which provides a benchmark for the impedance matching measurement technique.

  19. Cloud photogrammetry with dense stereo for fisheye cameras

    NASA Astrophysics Data System (ADS)

    Beekmans, Christoph; Schneider, Johannes; Läbe, Thomas; Lennefer, Martin; Stachniss, Cyrill; Simmer, Clemens

    2016-11-01

    We present a novel approach for dense 3-D cloud reconstruction above an area of 10 × 10 km2 using two hemispheric sky imagers with fisheye lenses in a stereo setup. We examine an epipolar rectification model designed for fisheye cameras, which allows the use of efficient out-of-the-box dense matching algorithms designed for classical pinhole-type cameras to search for correspondence information at every pixel. The resulting dense point cloud allows to recover a detailed and more complete cloud morphology compared to previous approaches that employed sparse feature-based stereo or assumed geometric constraints on the cloud field. Our approach is very efficient and can be fully automated. From the obtained 3-D shapes, cloud dynamics, size, motion, type and spacing can be derived, and used for radiation closure under cloudy conditions, for example. Fisheye lenses follow a different projection function than classical pinhole-type cameras and provide a large field of view with a single image. However, the computation of dense 3-D information is more complicated and standard implementations for dense 3-D stereo reconstruction cannot be easily applied. Together with an appropriate camera calibration, which includes internal camera geometry, global position and orientation of the stereo camera pair, we use the correspondence information from the stereo matching for dense 3-D stereo reconstruction of clouds located around the cameras. We implement and evaluate the proposed approach using real world data and present two case studies. In the first case, we validate the quality and accuracy of the method by comparing the stereo reconstruction of a stratocumulus layer with reflectivity observations measured by a cloud radar and the cloud-base height estimated from a Lidar-ceilometer. The second case analyzes a rapid cumulus evolution in the presence of strong wind shear.

  20. Hybrid-Based Dense Stereo Matching

    NASA Astrophysics Data System (ADS)

    Chuang, T. Y.; Ting, H. W.; Jaw, J. J.

    2016-06-01

    Stereo matching generating accurate and dense disparity maps is an indispensable technique for 3D exploitation of imagery in the fields of Computer vision and Photogrammetry. Although numerous solutions and advances have been proposed in the literature, occlusions, disparity discontinuities, sparse texture, image distortion, and illumination changes still lead to problematic issues and await better treatment. In this paper, a hybrid-based method based on semi-global matching is presented to tackle the challenges on dense stereo matching. To ease the sensitiveness of SGM cost aggregation towards penalty parameters, a formal way to provide proper penalty estimates is proposed. To this end, the study manipulates a shape-adaptive cross-based matching with an edge constraint to generate an initial disparity map for penalty estimation. Image edges, indicating the potential locations of occlusions as well as disparity discontinuities, are approved by the edge drawing algorithm to ensure the local support regions not to cover significant disparity changes. Besides, an additional penalty parameter 𝑃𝑒 is imposed onto the energy function of SGM cost aggregation to specifically handle edge pixels. Furthermore, the final disparities of edge pixels are found by weighting both values derived from the SGM cost aggregation and the U-SURF matching, providing more reliable estimates at disparity discontinuity areas. Evaluations on Middlebury stereo benchmarks demonstrate satisfactory performance and reveal the potency of the hybrid-based dense stereo matching method.

  1. Relocatable dense medium coal preparation plants for Indonesia

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lamb, R.

    1994-12-31

    The major recent coal mine developments in Indonesia have been situated along the east coast of Kalimantan (Borneo). Design and construction in these remote areas require a high level of innovation and ingenuity to ensure that the plants can be brought on line effectively. This paper describes the design, installation, and operation of two relocatable modular dense medium plants. The plants were specifically built to overcome the difficulties of remote areas and can be assembled by a semi-skilled workforce. The two relocatable dense medium coal preparation plants recently built for mines in Kalimantan are unique in that the plants weremore » fabricated, preassembled, and wet-commissioned in Brisbane, Australia, before shipment to Indonesia. The plants are a 3OO t/h dense medium bath, cyclone, and spirals plant and a 250 t/h dense medium cyclone and spirals with reject and tailings co-disposal. The relocatable plant concept has enabled a low capital cost per ton per hour and an extremely fast construction timetable-20 weeks from contract award to completion of wet-commissioning for shipment to Indonesia.« less

  2. Experiments with BECs in a Painted Potential: Atom SQUID, Matter Wave Bessel Beams, and Matter Wave Circuits

    NASA Astrophysics Data System (ADS)

    Boshier, Malcolm; Ryu, Changhyun; Blackburn, Paul; Blinova, Alina; Henderson, Kevin

    2014-05-01

    The painted potential is a time-averaged optical dipole potential which is able to create arbitrary and dynamic two dimensional potentials for Bose Einstein condensates (BECs). This poster reports three recent experiments using this technique. First, we have realized the dc atom SQUID geometry of a BEC in a toroidal trap with two Josephson junctions. We observe Josephson effects, measure the critical current of the junctions, and find dynamic behavior that is in good agreement with the simple Josephson equations for a tunnel junction with the ideal sinusoidal current-phase relation expected for the parameters of the experiment. Second, we have used free expansion of a rotating toroidal BEC to create matter wave Bessel beams, which are of interest because perfect Bessel beams (plane waves with amplitude profiles described by Bessel functions) propagate without diffraction. Third, we have realized the basic circuit elements necessary to create complex matter wave circuits. We launch BECs at arbitrary velocity along straight waveguides, propagate them around curved waveguides and stadium-shaped waveguide traps, and split them coherently at y-junctions that can also act as switches. Supported by LANL/LDRD.

  3. Droplet formation and scaling in dense suspensions

    PubMed Central

    Miskin, Marc Z.; Jaeger, Heinrich M.

    2012-01-01

    When a dense suspension is squeezed from a nozzle, droplet detachment can occur similar to that of pure liquids. While in pure liquids the process of droplet detachment is well characterized through self-similar profiles and known scaling laws, we show here the simple presence of particles causes suspensions to break up in a new fashion. Using high-speed imaging, we find that detachment of a suspension drop is described by a power law; specifically we find the neck minimum radius, rm, scales like near breakup at time τ = 0. We demonstrate data collapse in a variety of particle/liquid combinations, packing fractions, solvent viscosities, and initial conditions. We argue that this scaling is a consequence of particles deforming the neck surface, thereby creating a pressure that is balanced by inertia, and show how it emerges from topological constraints that relate particle configurations with macroscopic Gaussian curvature. This new type of scaling, uniquely enforced by geometry and regulated by the particles, displays memory of its initial conditions, fails to be self-similar, and has implications for the pressure given at generic suspension interfaces. PMID:22392979

  4. Arbitrary electron acoustic waves in degenerate dense plasmas

    NASA Astrophysics Data System (ADS)

    Rahman, Ata-ur; Mushtaq, A.; Qamar, A.; Neelam, S.

    2017-05-01

    A theoretical investigation is carried out of the nonlinear dynamics of electron-acoustic waves in a collisionless and unmagnetized plasma whose constituents are non-degenerate cold electrons, ultra-relativistic degenerate electrons, and stationary ions. A dispersion relation is derived for linear EAWs. An energy integral equation involving the Sagdeev potential is derived, and basic properties of the large amplitude solitary structures are investigated in such a degenerate dense plasma. It is shown that only negative large amplitude EA solitary waves can exist in such a plasma system. The present analysis may be important to understand the collective interactions in degenerate dense plasmas, occurring in dense astrophysical environments as well as in laser-solid density plasma interaction experiments.

  5. OH megamasers: dense gas & the infrared radiation field

    NASA Astrophysics Data System (ADS)

    Huang, Yong; Zhang, JiangShui; Liu, Wei; Xu, Jie

    2018-06-01

    To investigate possible factors related to OH megamaser formation (OH MM, L_{H2O}>10L_{⊙}), we compiled a large HCN sample from all well-sampled HCN measurements so far in local galaxies and identified with the OH MM, OH kilomasers (L_{H2O}<10L_{⊙}, OH kMs), OH absorbers and OH non-detections (non-OH MM). Through comparative analysis on their infrared emission, CO and HCN luminosities (good tracers for the low-density gas and the dense gas, respectively), we found that OH MM galaxies tend to have stronger HCN emission and no obvious difference on CO luminosity exists between OH MM and non-OH MM. This implies that OH MM formation should be related to the dense molecular gas, instead of the low-density molecular gas. It can be also supported by other facts: (1) OH MMs are confirmed to have higher mean molecular gas density and higher dense gas fraction (L_{HCN}/L_{CO}) than non-OH MMs. (2) After taking the distance effect into account, the apparent maser luminosity is still correlated with the HCN luminosity, while no significant correlation can be found at all between the maser luminosity and the CO luminosity. (3) The OH kMs tend to have lower values than those of OH MMs, including the dense gas luminosity and the dense gas fraction. (4) From analysis of known data of another dense gas tracer HCO^+, similar results can also be obtained. However, from our analysis, the infrared radiation field can not be ruled out for the OH MM trigger, which was proposed by previous works on one small sample (Darling in ApJ 669:L9, 2007). On the contrary, the infrared radiation field should play one more important role. The dense gas (good tracers of the star formation) and its surrounding dust are heated by the ultra-violet (UV) radiation generated by the star formation and the heating of the high-density gas raises the emission of the molecules. The infrared radiation field produced by the re-radiation of the heated dust in turn serves for the pumping of the OH MM.

  6. Low-velocity ion stopping in a dense and low-temperature plasma target

    NASA Astrophysics Data System (ADS)

    Deutsch, Claude; Popoff, Romain

    2007-07-01

    We investigate the stopping specificities involved in the heating of thin foils irradiated by intense ion beams in the 0.3-3 MeV/amu energy range and in close vicinity of the Bragg peak. Considering a swiftly ionized target to eV temperatures before expansion while retaining solid-state density, a typical warm dense matter (WDM) situation thus arises. We stress low Vp stopping through ion diffusion in the given target plasma. This allows to include the case of a strongly magnetized target in a guiding center approximation. We also demonstrate that the ion projectile penetration depth in target is significantly affected by multiple scattering on target electrons. The given plasma target is taken weakly coupled with Maxwell electron either with no magnetic field ( B=0) or strongly magnetized ( B≠0). Dynamical coupling between ion projectiles energy losses and projectiles charge state will also be addressed.

  7. A new form of strange matter and new hope for finding it

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Flam, F.

    Deep in the dense cores of collapsed stars even atoms don't survive. The force of gravity crushes them into particle mushes weighing megatons per teaspoon. But even these alien forms of matter don't hold a candle to another possible end product of a collapsing star: something physicists justifiably call strange matter. This strangeness comes from an exotic particle not associated with ordinary matter: the strange quark. It belongs to a six-member quark family, along with up, down, charm, top, and bottom, each of which carries a different combination of charge and mass. The only ones that make up matter asmore » we know it are up and down quarks, but in theory, matter could form out of strange quarks as well. In nature, it would turn up most probably in interiors of collapsed stars. Scientists originally imagined strange matter as a sort of disorganized mixed bag of strange quarks, but this summer a group proposed that the quarks could form a sort of mutant atomic nucleus that could conceivably grow to the size of a star. For the moment this is speculation, but it may not be theoretical musing for long. Physicists are preparing to try making strange matter here on Earth, in experiments at Brookhaven National Laboratory in New York and Switzerland's CERN, next summer.« less

  8. From sparse to dense and from assortative to disassortative in online social networks

    PubMed Central

    Li, Menghui; Guan, Shuguang; Wu, Chensheng; Gong, Xiaofeng; Li, Kun; Wu, Jinshan; Di, Zengru; Lai, Choy-Heng

    2014-01-01

    Inspired by the analysis of several empirical online social networks, we propose a simple reaction-diffusion-like coevolving model, in which individuals are activated to create links based on their states, influenced by local dynamics and their own intention. It is shown that the model can reproduce the remarkable properties observed in empirical online social networks; in particular, the assortative coefficients are neutral or negative, and the power law exponents γ are smaller than 2. Moreover, we demonstrate that, under appropriate conditions, the model network naturally makes transition(s) from assortative to disassortative, and from sparse to dense in their characteristics. The model is useful in understanding the formation and evolution of online social networks. PMID:24798703

  9. From sparse to dense and from assortative to disassortative in online social networks.

    PubMed

    Li, Menghui; Guan, Shuguang; Wu, Chensheng; Gong, Xiaofeng; Li, Kun; Wu, Jinshan; Di, Zengru; Lai, Choy-Heng

    2014-05-06

    Inspired by the analysis of several empirical online social networks, we propose a simple reaction-diffusion-like coevolving model, in which individuals are activated to create links based on their states, influenced by local dynamics and their own intention. It is shown that the model can reproduce the remarkable properties observed in empirical online social networks; in particular, the assortative coefficients are neutral or negative, and the power law exponents γ are smaller than 2. Moreover, we demonstrate that, under appropriate conditions, the model network naturally makes transition(s) from assortative to disassortative, and from sparse to dense in their characteristics. The model is useful in understanding the formation and evolution of online social networks.

  10. New State of Nuclear Matter: Nearly Perfect Fluid of Quarks and Gluons in Heavy Ion Collisions at RHIC Energies From Charged Particle Density to Jet Quenching

    DOE PAGES

    Nouicer, R.

    2016-03-28

    This article reviews several important results from RHIC experiments and discusses their implications. They were obtained in a unique environment for studying QCD matter at temperatures and densities that exceed the limits wherein hadrons can exist as individual entities and raises to prominence the quark-gluon degrees of freedom. These findings are supported by major experimental observations via measuring of the bulk properties of particle production, particle ratios and chemical freeze-out conditions, and elliptic ow; followed by hard probe measurements: high-pT hadron suppression, dijet fragment azimuthal correlations, and heavy favor probes. These measurements are presented for particles of different species asmore » a function of system sizes, collision centrality, and energy carried out in RHIC experiments. The results reveal that a dense, strongly-interacting medium is created in central Au + Au collisions at p sNN = 200 GeV at RHIC. This revelation of a new state of nuclear matter has also been observed in measurements at the LHC. Further, the IP-Glasma model coupled with viscous hydrodynamic models, which assumes the formation of a QGP, reproduces well the experimental ow results from Au + Au at p sNN = 200 GeV. This implies that the fluctuations in the initial geometry state are important and the created medium behaves as a nearly perfect liquid of nuclear matter because it has an extraordinarily low ratio of shear viscosity to entropy density, =s 0.12. However, these discoveries are far from being fully understood. Furthermore, recent experimental results from RHIC and LHC in small p + A, d + Au and 3He+Au collision systems provide brand new insight into the role of initial and final state effects. These have proven to be interesting and more surprising than originally anticipated; and could conceivably shed new light in our understanding of collective behavior in heavy-ion physics. Accordingly, the focus of the experiments at both facilities RHIC and

  11. New state of nuclear matter: Nearly perfect fluid of quarks and gluons in heavy-ion collisions at RHIC energies. From charged particle density to jet quenching

    NASA Astrophysics Data System (ADS)

    Nouicer, R.

    2016-03-01

    This article reviews several important results from RHIC experiments and discusses their implications. They were obtained in a unique environment for studying QCD matter at temperatures and densities that exceed the limits wherein hadrons can exist as individual entities and raises to prominence the quark-gluon degrees of freedom. These findings are supported by major experimental observations via measuring of the bulk properties of particle production, particle ratios and chemical freeze-out conditions, and elliptic flow; followed by hard probe measurements: high- pT hadron suppression, dijet fragment azimuthal correlations, and heavy-flavor probes. These measurements are presented for particles of different species as a function of system sizes, collision centrality, and energy carried out in RHIC experiments. The results reveal that a dense, strongly interacting medium is created in central Au+Au collisions at sqrt{s_{NN}} = 200 GeV at RHIC. This revelation of a new state of nuclear matter has also been observed in measurements at the LHC. Further, the IP-Glasma model coupled with viscous hydrodynamic models, which assumes the formation of a QGP, reproduces well the experimental flow results from Au+Au at sqrt{s_{NN}} = 200 GeV. This implies that the fluctuations in the initial geometry state are important and the created medium behaves as a nearly perfect liquid of nuclear matter because it has an extraordinarily low ratio of shear viscosity to entropy density, η/s≈ 0.12. However, these discoveries are far from being fully understood. Furthermore, recent experimental results from RHIC and LHC in small p+A, d+ Au and 3He+Au collision systems provide brand new insight into the role of initial and final state effects. These have proven to be interesting and more surprising than originally anticipated; and could conceivably shed new light in our understanding of collective behavior in heavy-ion physics. Accordingly, the focus of the experiments at both

  12. New State of Nuclear Matter: Nearly Perfect Fluid of Quarks and Gluons in Heavy Ion Collisions at RHIC Energies From Charged Particle Density to Jet Quenching

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Nouicer, R.

    This article reviews several important results from RHIC experiments and discusses their implications. They were obtained in a unique environment for studying QCD matter at temperatures and densities that exceed the limits wherein hadrons can exist as individual entities and raises to prominence the quark-gluon degrees of freedom. These findings are supported by major experimental observations via measuring of the bulk properties of particle production, particle ratios and chemical freeze-out conditions, and elliptic ow; followed by hard probe measurements: high-pT hadron suppression, dijet fragment azimuthal correlations, and heavy favor probes. These measurements are presented for particles of different species asmore » a function of system sizes, collision centrality, and energy carried out in RHIC experiments. The results reveal that a dense, strongly-interacting medium is created in central Au + Au collisions at p sNN = 200 GeV at RHIC. This revelation of a new state of nuclear matter has also been observed in measurements at the LHC. Further, the IP-Glasma model coupled with viscous hydrodynamic models, which assumes the formation of a QGP, reproduces well the experimental ow results from Au + Au at p sNN = 200 GeV. This implies that the fluctuations in the initial geometry state are important and the created medium behaves as a nearly perfect liquid of nuclear matter because it has an extraordinarily low ratio of shear viscosity to entropy density, =s 0.12. However, these discoveries are far from being fully understood. Furthermore, recent experimental results from RHIC and LHC in small p + A, d + Au and 3He+Au collision systems provide brand new insight into the role of initial and final state effects. These have proven to be interesting and more surprising than originally anticipated; and could conceivably shed new light in our understanding of collective behavior in heavy-ion physics. Accordingly, the focus of the experiments at both facilities RHIC and

  13. Two Novel Rab2 Interactors Regulate Dense-core Vesicle Maturation

    PubMed Central

    Ailion, Michael; Hannemann, Mandy; Dalton, Susan; Pappas, Andrea; Watanabe, Shigeki; Hegermann, Jan; Liu, Qiang; Han, Hsiao-Fen; Gu, Mingyu; Goulding, Morgan Q.; Sasidharan, Nikhil; Schuske, Kim; Hullett, Patrick; Eimer, Stefan; Jorgensen, Erik M.

    2014-01-01

    Summary Peptide neuromodulators are released from a unique organelle: the dense-core vesicle. Dense-core vesicles are generated at the trans-Golgi, and then sort cargo during maturation before being secreted. To identify proteins that act in this pathway, we performed a genetic screen in Caenorhabditis elegans for mutants defective in dense-core vesicle function. We identified two conserved Rab2-binding proteins: RUND-1, a RUN domain protein, and CCCP-1, a coiled-coil protein. RUND-1 and CCCP-1 colocalize with RAB-2 at the Golgi, and rab-2, rund-1 and cccp-1 mutants have similar defects in sorting soluble and transmembrane dense-core vesicle cargos. RUND-1 also interacts with the Rab2 GAP protein TBC-8 and the BAR domain protein RIC-19, a RAB-2 effector. In summary, a new pathway of conserved proteins controls the maturation of dense-core vesicles at the trans-Golgi network. PMID:24698274

  14. Dense power-law networks and simplicial complexes

    NASA Astrophysics Data System (ADS)

    Courtney, Owen T.; Bianconi, Ginestra

    2018-05-01

    There is increasing evidence that dense networks occur in on-line social networks, recommendation networks and in the brain. In addition to being dense, these networks are often also scale-free, i.e., their degree distributions follow P (k ) ∝k-γ with γ ∈(1 ,2 ] . Models of growing networks have been successfully employed to produce scale-free networks using preferential attachment, however these models can only produce sparse networks as the numbers of links and nodes being added at each time step is constant. Here we present a modeling framework which produces networks that are both dense and scale-free. The mechanism by which the networks grow in this model is based on the Pitman-Yor process. Variations on the model are able to produce undirected scale-free networks with exponent γ =2 or directed networks with power-law out-degree distribution with tunable exponent γ ∈(1 ,2 ) . We also extend the model to that of directed two-dimensional simplicial complexes. Simplicial complexes are generalization of networks that can encode the many body interactions between the parts of a complex system and as such are becoming increasingly popular to characterize different data sets ranging from social interacting systems to the brain. Our model produces dense directed simplicial complexes with power-law distribution of the generalized out-degrees of the nodes.

  15. Multiple elastic scattering of electrons in condensed matter

    NASA Astrophysics Data System (ADS)

    Jablonski, A.

    2017-01-01

    Since the 1940s, much attention has been devoted to the problem of accurate theoretical description of electron transport in condensed matter. The needed information for describing different aspects of the electron transport is the angular distribution of electron directions after multiple elastic collisions. This distribution can be expanded into a series of Legendre polynomials with coefficients, Al. In the present work, a database of these coefficients for all elements up to uranium (Z=92) and a dense grid of electron energies varying from 50 to 5000 eV has been created. The database makes possible the following applications: (i) accurate interpolation of coefficients Al for any element and any energy from the above range, (ii) fast calculations of the differential and total elastic-scattering cross sections, (iii) determination of the angular distribution of directions after multiple collisions, (iv) calculations of the probability of elastic backscattering from solids, and (v) calculations of the calibration curves for determination of the inelastic mean free paths of electrons. The last two applications provide data with comparable accuracy to Monte Carlo simulations, yet the running time is decreased by several orders of magnitude. All of the above applications are implemented in the Fortran program MULTI_SCATT. Numerous illustrative runs of this program are described. Despite a relatively large volume of the database of coefficients Al, the program MULTI_SCATT can be readily run on personal computers.

  16. A Green Method for Processing Polymers using Dense Gas Technology

    PubMed Central

    Yoganathan, Roshan B.; Mammucari, Raffaella; Foster, Neil R.

    2010-01-01

    Dense CO2 can be used as an environmentally-benign polymer processing medium because of its liquid-like densities and gas-like mass transfer properties.In this work, polymer bio-blends of polycarbonate (PC), a biocompatible polymer, and polycaprolactone (PCL), a biodegradable polymer were prepared. Dense CO2 was used as a reaction medium for the melt-phase PC polymerization in the presence of dense CO2-swollen PCL particles and this method was used to prepare porous PC/PCL blends. To extend the applicability of dense CO2 to the biomedical industry and polymer blend processing, the impregnation of ibuprofen into the blend was conducted and subsequent dissolution characteristics were observed.

  17. Dark Matter Hairs Around Earth

    NASA Image and Video Library

    2015-11-23

    This illustration shows Earth surrounded by filaments of dark matter called "hairs," which are proposed in a study in the Astrophysical Journal by Gary Prézeau of NASA's Jet Propulsion Laboratory, Pasadena, California. A hair is created when a stream of dark matter particles goes through the planet. According to simulations, the hair is densest at a point called the "root." When particles of a dark matter stream pass through the core of Earth, they form a hair whose root has a particle density about a billion times greater than average. The hairs in this illustration are not to scale. Simulations show that the roots of such hairs can be 600,000 miles (1 million kilometers) from Earth, while Earth's radius is only about 4,000 miles (6,400 kilometers). http://photojournal.jpl.nasa.gov/catalog/PIA20176

  18. Symmetry breaking, and the effect of matter density on neutrino oscillation

    NASA Astrophysics Data System (ADS)

    Mohseni Sadjadi, H.; Khosravi Karchi, A. P.

    2018-04-01

    A proposal for the neutrino mass, based on neutrino-scalar field interaction, is introduced. The scalar field is also non-minimally coupled to the Ricci scalar, and hence relates the neutrino mass to the matter density. In a dense region, the scalar field obeys the Z2 symmetry, and the neutrino is massless. In a dilute region, the Z2 symmetry breaks and neutrino acquires mass from the non-vanishing expectation value of the scalar field. We consider this scenario in the framework of a spherical dense object whose outside is a dilute region. In this background, we study the neutrino flavors oscillation, along with the consequences of the theory on oscillation length and MSW effect. This preliminary model may shed some lights on the existing anomalies within the neutrino data, concerning the different oscillating behavior of the neutrinos in regions with different densities.

  19. Kinetic simulations of gas breakdown in the dense plasma focus

    NASA Astrophysics Data System (ADS)

    Bennett, N.; Blasco, M.; Breeding, K.; DiPuccio, V.; Gall, B.; Garcia, M.; Gardner, S.; Gatling, J.; Hagen, E. C.; Luttman, A.; Meehan, B. T.; Molnar, S.; O'Brien, R.; Ormond, E.; Robbins, L.; Savage, M.; Sipe, N.; Welch, D. R.

    2017-06-01

    The first fully kinetic, collisional, and electromagnetic simulations of the breakdown phase of a MA-scale dense plasma focus are described and shown to agree with measured electrical characteristics, including breakdown time. In the model, avalanche ionization is driven by cathode electron emission, and this results in incomplete gas breakdown along the insulator. This reinforces the importance of the conditioning process that creates a metallic layer on the insulator surface. The simulations, nonetheless, help explain the relationship between the gas pressure, the insulator length, and the coaxial gap width. Previously, researchers noted three breakdown patterns related to pressure. Simulation and analytical results show that at low pressures, long ionization path lengths lead to volumetric breakdown, while high pressures lead to breakdown across the relatively small coaxial electrode gap. In an intermediate pressure regime, ionization path lengths are comparable to the insulator length which promotes ideal breakdown along the insulator surface.

  20. Fundamental Studies of Droplet Interactions in Dense Sprays

    DTIC Science & Technology

    1992-12-31

    correlations for the drag coefficients, Nusselt numbers, and Sherwood numbers for hydrocarbon fuel droplets in dense sprays were obtained. 14. SUBJECYTEM...tions for the drag coefficients, Nusselt numbers, and Sherwood numbers for hydrocarbon fuel droplets in dense sprays were obtained. Nomenclature a...the drag coefficient, lift coefficient, moment coefficient, Nusselt number, Sherwood number, and vaporization rates are different from those of an

  1. Manufacture of dense sintered bodies containing silicon nitride

    NASA Technical Reports Server (NTRS)

    Hirota, K.; Hasegawa, Y.; Ogura, K.; Yashima, Y.

    1985-01-01

    Sintered bodies containing 1-32.5 Si oxide and 1.5 wt.% SiC (Si oxide/SiC wt. ratio 3/2) are prepared and kept in a 10-3000 kg/2 sq. cm. N (g) atmosphere at 1500-2300 degrees, while simultaneously maintaining the CO (g) partial pressure around the body lower than the nitrogenation equil. pressure to give a dense sintered body. The prepared dense sintered body has high strength at high temperatures. Thus, SiC 40, oxide 30 and Si3N4 30 wt% were fired to a body which was kept in 1500 kg/sq. cm. N (g) for 20 h at 2000 degrees to give a dense sintered body having high bending strength at high temperatures.

  2. Percolation transition in Yang-Mills matter at a finite number of colors.

    PubMed

    Lottini, Stefano; Torrieri, Giorgio

    2011-10-07

    We examine baryonic matter at a quark chemical potential of the order of the confinement scale μ(q)∼Λ(QCD). In this regime, quarks are supposed to be confined but baryons are close to the "tightly packed limit" where they nearly overlap in configuration space. We show that this system will exhibit a percolation phase transition when varied in the number of colors N(c): at high N(c), large distance correlations at the quark level are possible even if the quarks are essentially confined. At low N(c), this does not happen. We discuss the relevance of this for dense nuclear matter, and argue that our results suggest a new "phase transition," varying N(c) at constant μ(q).

  3. Creating high-resolution bare-earth digital elevation models (DEMs) from stereo imagery in an area of densely vegetated deciduous forest using combinations of procedures designed for lidar point cloud filtering

    USGS Publications Warehouse

    DeWitt, Jessica D.; Warner, Timothy A.; Chirico, Peter G.; Bergstresser, Sarah E.

    2017-01-01

    For areas of the world that do not have access to lidar, fine-scale digital elevation models (DEMs) can be photogrammetrically created using globally available high-spatial resolution stereo satellite imagery. The resultant DEM is best termed a digital surface model (DSM) because it includes heights of surface features. In densely vegetated conditions, this inclusion can limit its usefulness in applications requiring a bare-earth DEM. This study explores the use of techniques designed for filtering lidar point clouds to mitigate the elevation artifacts caused by above ground features, within the context of a case study of Prince William Forest Park, Virginia, USA. The influences of land cover and leaf-on vs. leaf-off conditions are investigated, and the accuracy of the raw photogrammetric DSM extracted from leaf-on imagery was between that of a lidar bare-earth DEM and the Shuttle Radar Topography Mission DEM. Although the filtered leaf-on photogrammetric DEM retains some artifacts of the vegetation canopy and may not be useful for some applications, filtering procedures significantly improved the accuracy of the modeled terrain. The accuracy of the DSM extracted in leaf-off conditions was comparable in most areas to the lidar bare-earth DEM and filtering procedures resulted in accuracy comparable of that to the lidar DEM.

  4. Eculizumab for dense deposit disease and C3 glomerulonephritis.

    PubMed

    Bomback, Andrew S; Smith, Richard J; Barile, Gaetano R; Zhang, Yuzhou; Heher, Eliot C; Herlitz, Leal; Stokes, M Barry; Markowitz, Glen S; D'Agati, Vivette D; Canetta, Pietro A; Radhakrishnan, Jai; Appel, Gerald B

    2012-05-01

    The principle defect in dense deposit disease and C3 glomerulonephritis is hyperactivity of the alternative complement pathway. Eculizumab, a monoclonal antibody that binds to C5 to prevent formation of the membrane attack complex, may prove beneficial. In this open-label, proof of concept efficacy and safety study, six subjects with dense deposit disease or C3 glomerulonephritis were treated with eculizumab every other week for 1 year. All had proteinuria >1 g/d and/or AKI at enrollment. Subjects underwent biopsy before enrollment and repeat biopsy at the 1-year mark. The subjects included three patients with dense deposit disease (including one patient with recurrent dense deposit disease in allograft) and three patients with C3 glomerulonephritis (including two patients with recurrent C3 glomerulonephritis in allograft). Genetic and complement function testing revealed a mutation in CFH and MCP in one subject each, C3 nephritic factor in three subjects, and elevated levels of serum membrane attack complex in three subjects. After 12 months, two subjects showed significantly reduced serum creatinine, one subject achieved marked reduction in proteinuria, and one subject had stable laboratory parameters but histopathologic improvements. Elevated serum membrane attack complex levels normalized on therapy and paralleled improvements in creatinine and proteinuria. Clinical and histopathologic data suggest a response to eculizumab in some but not all subjects with dense deposit disease and C3 glomerulonephritis. Elevation of serum membrane attack complex before treatment may predict response. Additional research is needed to define the subgroup of dense deposit disease/C3 glomerulonephritis patients in whom eculizumab therapy can be considered.

  5. Deep-sea bioluminescence blooms after dense water formation at the ocean surface.

    PubMed

    Tamburini, Christian; Canals, Miquel; Durrieu de Madron, Xavier; Houpert, Loïc; Lefèvre, Dominique; Martini, Séverine; D'Ortenzio, Fabrizio; Robert, Anne; Testor, Pierre; Aguilar, Juan Antonio; Samarai, Imen Al; Albert, Arnaud; André, Michel; Anghinolfi, Marco; Anton, Gisela; Anvar, Shebli; Ardid, Miguel; Jesus, Ana Carolina Assis; Astraatmadja, Tri L; Aubert, Jean-Jacques; Baret, Bruny; Basa, Stéphane; Bertin, Vincent; Biagi, Simone; Bigi, Armando; Bigongiari, Ciro; Bogazzi, Claudio; Bou-Cabo, Manuel; Bouhou, Boutayeb; Bouwhuis, Mieke C; Brunner, Jurgen; Busto, José; Camarena, Francisco; Capone, Antonio; Cârloganu, Christina; Carminati, Giada; Carr, John; Cecchini, Stefano; Charif, Ziad; Charvis, Philippe; Chiarusi, Tommaso; Circella, Marco; Coniglione, Rosa; Costantini, Heide; Coyle, Paschal; Curtil, Christian; Decowski, Patrick; Dekeyser, Ivan; Deschamps, Anne; Donzaud, Corinne; Dornic, Damien; Dorosti, Hasankiadeh Q; Drouhin, Doriane; Eberl, Thomas; Emanuele, Umberto; Ernenwein, Jean-Pierre; Escoffier, Stéphanie; Fermani, Paolo; Ferri, Marcelino; Flaminio, Vincenzo; Folger, Florian; Fritsch, Ulf; Fuda, Jean-Luc; Galatà, Salvatore; Gay, Pascal; Giacomelli, Giorgio; Giordano, Valentina; Gómez-González, Juan-Pablo; Graf, Kay; Guillard, Goulven; Halladjian, Garadeb; Hallewell, Gregory; van Haren, Hans; Hartman, Joris; Heijboer, Aart J; Hello, Yann; Hernández-Rey, Juan Jose; Herold, Bjoern; Hößl, Jurgen; Hsu, Ching-Cheng; de Jong, Marteen; Kadler, Matthias; Kalekin, Oleg; Kappes, Alexander; Katz, Uli; Kavatsyuk, Oksana; Kooijman, Paul; Kopper, Claudio; Kouchner, Antoine; Kreykenbohm, Ingo; Kulikovskiy, Vladimir; Lahmann, Robert; Lamare, Patrick; Larosa, Giuseppina; Lattuada, Dario; Lim, Gordon; Presti, Domenico Lo; Loehner, Herbert; Loucatos, Sotiris; Mangano, Salvatore; Marcelin, Michel; Margiotta, Annarita; Martinez-Mora, Juan Antonio; Meli, Athina; Montaruli, Teresa; Moscoso, Luciano; Motz, Holger; Neff, Max; Nezri, Emma Nuel; Palioselitis, Dimitris; Păvălaş, Gabriela E; Payet, Kevin; Payre, Patrice; Petrovic, Jelena; Piattelli, Paolo; Picot-Clemente, Nicolas; Popa, Vlad; Pradier, Thierry; Presani, Eleonora; Racca, Chantal; Reed, Corey; Riccobene, Giorgio; Richardt, Carsten; Richter, Roland; Rivière, Colas; Roensch, Kathrin; Rostovtsev, Andrei; Ruiz-Rivas, Joaquin; Rujoiu, Marius; Russo, Valerio G; Salesa, Francisco; Sánchez-Losa, Augustin; Sapienza, Piera; Schöck, Friederike; Schuller, Jean-Pierre; Schussler, Fabian; Shanidze, Rezo; Simeone, Francesco; Spies, Andreas; Spurio, Maurizio; Steijger, Jos J M; Stolarczyk, Thierry; Taiuti, Mauro G F; Toscano, Simona; Vallage, Bertrand; Van Elewyck, Véronique; Vannoni, Giulia; Vecchi, Manuela; Vernin, Pascal; Wijnker, Guus; Wilms, Jorn; de Wolf, Els; Yepes, Harold; Zaborov, Dmitry; De Dios Zornoza, Juan; Zúñiga, Juan

    2013-01-01

    The deep ocean is the largest and least known ecosystem on Earth. It hosts numerous pelagic organisms, most of which are able to emit light. Here we present a unique data set consisting of a 2.5-year long record of light emission by deep-sea pelagic organisms, measured from December 2007 to June 2010 at the ANTARES underwater neutrino telescope in the deep NW Mediterranean Sea, jointly with synchronous hydrological records. This is the longest continuous time-series of deep-sea bioluminescence ever recorded. Our record reveals several weeks long, seasonal bioluminescence blooms with light intensity up to two orders of magnitude higher than background values, which correlate to changes in the properties of deep waters. Such changes are triggered by the winter cooling and evaporation experienced by the upper ocean layer in the Gulf of Lion that leads to the formation and subsequent sinking of dense water through a process known as "open-sea convection". It episodically renews the deep water of the study area and conveys fresh organic matter that fuels the deep ecosystems. Luminous bacteria most likely are the main contributors to the observed deep-sea bioluminescence blooms. Our observations demonstrate a consistent and rapid connection between deep open-sea convection and bathypelagic biological activity, as expressed by bioluminescence. In a setting where dense water formation events are likely to decline under global warming scenarios enhancing ocean stratification, in situ observatories become essential as environmental sentinels for the monitoring and understanding of deep-sea ecosystem shifts.

  6. Deep-Sea Bioluminescence Blooms after Dense Water Formation at the Ocean Surface

    PubMed Central

    Tamburini, Christian; Canals, Miquel; Durrieu de Madron, Xavier; Houpert, Loïc; Lefèvre, Dominique; Martini, Séverine; D'Ortenzio, Fabrizio; Robert, Anne; Testor, Pierre; Aguilar, Juan Antonio; Samarai, Imen Al; Albert, Arnaud; André, Michel; Anghinolfi, Marco; Anton, Gisela; Anvar, Shebli; Ardid, Miguel; Jesus, Ana Carolina Assis; Astraatmadja, Tri L.; Aubert, Jean-Jacques; Baret, Bruny; Basa, Stéphane; Bertin, Vincent; Biagi, Simone; Bigi, Armando; Bigongiari, Ciro; Bogazzi, Claudio; Bou-Cabo, Manuel; Bouhou, Boutayeb; Bouwhuis, Mieke C.; Brunner, Jurgen; Busto, José; Camarena, Francisco; Capone, Antonio; Cârloganu, Christina; Carminati, Giada; Carr, John; Cecchini, Stefano; Charif, Ziad; Charvis, Philippe; Chiarusi, Tommaso; Circella, Marco; Coniglione, Rosa; Costantini, Heide; Coyle, Paschal; Curtil, Christian; Decowski, Patrick; Dekeyser, Ivan; Deschamps, Anne; Donzaud, Corinne; Dornic, Damien; Dorosti, Hasankiadeh Q.; Drouhin, Doriane; Eberl, Thomas; Emanuele, Umberto; Ernenwein, Jean-Pierre; Escoffier, Stéphanie; Fermani, Paolo; Ferri, Marcelino; Flaminio, Vincenzo; Folger, Florian; Fritsch, Ulf; Fuda, Jean-Luc; Galatà, Salvatore; Gay, Pascal; Giacomelli, Giorgio; Giordano, Valentina; Gómez-González, Juan-Pablo; Graf, Kay; Guillard, Goulven; Halladjian, Garadeb; Hallewell, Gregory; van Haren, Hans; Hartman, Joris; Heijboer, Aart J.; Hello, Yann; Hernández-Rey, Juan Jose; Herold, Bjoern; Hößl, Jurgen; Hsu, Ching-Cheng; de Jong, Marteen; Kadler, Matthias; Kalekin, Oleg; Kappes, Alexander; Katz, Uli; Kavatsyuk, Oksana; Kooijman, Paul; Kopper, Claudio; Kouchner, Antoine; Kreykenbohm, Ingo; Kulikovskiy, Vladimir; Lahmann, Robert; Lamare, Patrick; Larosa, Giuseppina; Lattuada, Dario; Lim, Gordon; Presti, Domenico Lo; Loehner, Herbert; Loucatos, Sotiris; Mangano, Salvatore; Marcelin, Michel; Margiotta, Annarita; Martinez-Mora, Juan Antonio; Meli, Athina; Montaruli, Teresa; Motz, Holger; Neff, Max; Nezri, Emma nuel; Palioselitis, Dimitris; Păvălaş, Gabriela E.; Payet, Kevin; Payre, Patrice; Petrovic, Jelena; Piattelli, Paolo; Picot-Clemente, Nicolas; Popa, Vlad; Pradier, Thierry; Presani, Eleonora; Racca, Chantal; Reed, Corey; Riccobene, Giorgio; Richardt, Carsten; Richter, Roland; Rivière, Colas; Roensch, Kathrin; Rostovtsev, Andrei; Ruiz-Rivas, Joaquin; Rujoiu, Marius; Russo, Valerio G.; Salesa, Francisco; Sánchez-Losa, Augustin; Sapienza, Piera; Schöck, Friederike; Schuller, Jean-Pierre; Schussler, Fabian; Shanidze, Rezo; Simeone, Francesco; Spies, Andreas; Spurio, Maurizio; Steijger, Jos J. M.; Stolarczyk, Thierry; Taiuti, Mauro G. F.; Toscano, Simona; Vallage, Bertrand; Van Elewyck, Véronique; Vannoni, Giulia; Vecchi, Manuela; Vernin, Pascal; Wijnker, Guus; Wilms, Jorn; de Wolf, Els; Yepes, Harold; Zaborov, Dmitry; De Dios Zornoza, Juan; Zúñiga, Juan

    2013-01-01

    The deep ocean is the largest and least known ecosystem on Earth. It hosts numerous pelagic organisms, most of which are able to emit light. Here we present a unique data set consisting of a 2.5-year long record of light emission by deep-sea pelagic organisms, measured from December 2007 to June 2010 at the ANTARES underwater neutrino telescope in the deep NW Mediterranean Sea, jointly with synchronous hydrological records. This is the longest continuous time-series of deep-sea bioluminescence ever recorded. Our record reveals several weeks long, seasonal bioluminescence blooms with light intensity up to two orders of magnitude higher than background values, which correlate to changes in the properties of deep waters. Such changes are triggered by the winter cooling and evaporation experienced by the upper ocean layer in the Gulf of Lion that leads to the formation and subsequent sinking of dense water through a process known as “open-sea convection”. It episodically renews the deep water of the study area and conveys fresh organic matter that fuels the deep ecosystems. Luminous bacteria most likely are the main contributors to the observed deep-sea bioluminescence blooms. Our observations demonstrate a consistent and rapid connection between deep open-sea convection and bathypelagic biological activity, as expressed by bioluminescence. In a setting where dense water formation events are likely to decline under global warming scenarios enhancing ocean stratification, in situ observatories become essential as environmental sentinels for the monitoring and understanding of deep-sea ecosystem shifts. PMID:23874425

  7. Dilute and dense axion stars

    NASA Astrophysics Data System (ADS)

    Visinelli, Luca; Baum, Sebastian; Redondo, Javier; Freese, Katherine; Wilczek, Frank

    2018-02-01

    Axion stars are hypothetical objects formed of axions, obtained as localized and coherently oscillating solutions to their classical equation of motion. Depending on the value of the field amplitude at the core |θ0 | ≡ | θ (r = 0) |, the equilibrium of the system arises from the balance of the kinetic pressure and either self-gravity or axion self-interactions. Starting from a general relativistic framework, we obtain the set of equations describing the configuration of the axion star, which we solve as a function of |θ0 |. For small |θ0 | ≲ 1, we reproduce results previously obtained in the literature, and we provide arguments for the stability of such configurations in terms of first principles. We compare qualitative analytical results with a numerical calculation. For large amplitudes |θ0 | ≳ 1, the axion field probes the full non-harmonic QCD chiral potential and the axion star enters the dense branch. Our numerical solutions show that in this latter regime the axions are relativistic, and that one should not use a single frequency approximation, as previously applied in the literature. We employ a multi-harmonic expansion to solve the relativistic equation for the axion field in the star, and demonstrate that higher modes cannot be neglected in the dense regime. We interpret the solutions in the dense regime as pseudo-breathers, and show that the life-time of such configurations is much smaller than any cosmological time scale.

  8. First-principles opacity table of warm dense deuterium for inertial-confinement-fusion applications.

    PubMed

    Hu, S X; Collins, L A; Goncharov, V N; Boehly, T R; Epstein, R; McCrory, R L; Skupsky, S

    2014-09-01

    Accurate knowledge of the optical properties of a warm dense deuterium-tritium (DT) mixture is important for reliable design of inertial confinement fusion (ICF) implosions using radiation-hydrodynamics simulations. The opacity of a warm dense DT shell essentially determines how much radiation from hot coronal plasmas can be deposited in the DT fuel of an imploding capsule. Even for the simplest species of hydrogen, the accurate calculation of their opacities remains a challenge in the warm-dense matter regime because strong-coupling and quantum effects play an important role in such plasmas. With quantum-molecular-dynamics (QMD) simulations, we have derived a first-principles opacity table (FPOT) of deuterium (and the DT mixture by mass scaling) for a wide range of densities from ρ(D)=0.5 to 673.518g/cm(3) and temperatures from T=5000K up to the Fermi temperature T(F) for each density. Compared with results from the astrophysics opacity table (AOT) currently used in our hydrocodes, the FPOT of deuterium from our QMD calculations has shown a significant increase in opacity for strongly coupled and degenerate plasma conditions by a factor of 3-100 in the ICF-relevant photon-energy range. As conditions approach those of classical plasma, the opacity from the FPOT converges to the corresponding values of the AOT. By implementing the FPOT of deuterium and the DT mixture into our hydrocodes, we have performed radiation-hydrodynamics simulations for low-adiabat cryogenic DT implosions on the OMEGA laser and for direct-drive-ignition designs for the National Ignition Facility. The simulation results using the FPOT show that the target performance (in terms of neutron yield and energy gain) could vary from ∼10% up to a factor of ∼2 depending on the adiabat of the imploding DT capsule; the lower the adiabat, the more variation is seen in the prediction of target performance when compared to the AOT modeling.

  9. Hugoniot measurements of double-shocked precompressed dense xenon plasmas

    NASA Astrophysics Data System (ADS)

    Zheng, J.; Chen, Q. F.; Gu, Y. J.; Chen, Z. Y.

    2012-12-01

    The current partially ionized plasmas models for xenon show substantial differences since the description of pressure and thermal ionization region becomes a formidable task, prompting the need for an improved understanding of dense xenon plasmas behavior at above 100 GPa. We performed double-shock compression experiments on dense xenon to determine accurately the Hugoniot up to 172 GPa using a time-resolved optical radiation method. The planar strong shock wave was produced using a flyer plate impactor accelerated up to ˜6 km/s with a two-stage light-gas gun. The time-resolved optical radiation histories were acquired by using a multiwavelength channel optical transience radiance pyrometer. Shock velocity was measured and mass velocity was determined by the impedance-matching methods. The experimental equation of state of dense xenon plasmas are compared with the self-consistent fluid variational calculations of dense xenon in the region of partial ionization over a wide range of pressures and temperatures.

  10. Fabrication, Properties and Applications of Dense Hydroxyapatite: A Review

    PubMed Central

    Prakasam, Mythili; Locs, Janis; Salma-Ancane, Kristine; Loca, Dagnija; Largeteau, Alain; Berzina-Cimdina, Liga

    2015-01-01

    In the last five decades, there have been vast advances in the field of biomaterials, including ceramics, glasses, glass-ceramics and metal alloys. Dense and porous ceramics have been widely used for various biomedical applications. Current applications of bioceramics include bone grafts, spinal fusion, bone repairs, bone fillers, maxillofacial reconstruction, etc. Amongst the various calcium phosphate compositions, hydroxyapatite, which has a composition similar to human bone, has attracted wide interest. Much emphasis is given to tissue engineering, both in porous and dense ceramic forms. The current review focusses on the various applications of dense hydroxyapatite and other dense biomaterials on the aspects of transparency and the mechanical and electrical behavior. Prospective future applications, established along the aforesaid applications of hydroxyapatite, appear to be promising regarding bone bonding, advanced medical treatment methods, improvement of the mechanical strength of artificial bone grafts and better in vitro/in vivo methodologies to afford more particular outcomes. PMID:26703750

  11. Ultrafast Absorption Spectroscopy of Aluminum Plasmas Created by LCLS using Betatron X-Ray Radiation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Albert, Felicie

    2016-10-12

    This document summarizes the goals and accomplishments of a six month-long LDRD project, awarded through the LLNL director Early and Mid Career Recognition (EMCR) program. This project allowed us to support beamtime awarded at the Matter under Extreme Conditions (MEC) end station of the Linac Coherent Light Source (LCLS). The goal of the experiment was to heat metallic samples with the bright x-rays from the LCLS free electron laser. Then, we studied how they relaxed back to equilibrium by probing them with ultrafast x-ray absorption spectroscopy using laser-based betatron radiation. Our work enabled large collaborations between LLNL, SLAC, LBNL, andmore » institutions in France and in the UK, while providing training to undergraduate and graduate students during the experiment. Following this LDRD project, the PI was awarded a 5-year DOE early career research grant to further develop applications of laser-driven x-ray sources for high energy density science experiments and warm dense matter states.« less

  12. Processes for making dense, spherical active materials for lithium-ion cells

    DOEpatents

    Kang, Sun-Ho [Naperville, IL; Amine, Khalil [Downers Grove, IL

    2011-11-22

    Processes are provided for making dense, spherical mixed-metal carbonate or phosphate precursors that are particularly well suited for the production of active materials for electrochemical devices such as lithium ion secondary batteries. Exemplified methods include precipitating dense, spherical particles of metal carbonates or metal phosphates from a combined aqueous solution using a precipitating agent such as ammonium hydrogen carbonate, sodium hydrogen carbonate, or a mixture that includes sodium hydrogen carbonate. Other exemplified methods include precipitating dense, spherical particles of metal phosphates using a precipitating agent such as ammonium hydrogen phosphate, ammonium dihydrogen phosphate, sodium phosphate, sodium hydrogen phosphate, sodium dihydrogen phosphate, or a mixture of any two or more thereof. Further provided are compositions of and methods of making dense, spherical metal oxides and metal phosphates using the dense, spherical metal precursors. Still further provided are electrodes and batteries using the same.

  13. Eculizumab for Dense Deposit Disease and C3 Glomerulonephritis

    PubMed Central

    Smith, Richard J.; Barile, Gaetano R.; Zhang, Yuzhou; Heher, Eliot C.; Herlitz, Leal; Stokes, M. Barry; Markowitz, Glen S.; D’Agati, Vivette D.; Canetta, Pietro A.; Radhakrishnan, Jai; Appel, Gerald B.

    2012-01-01

    Summary Background and objectives The principle defect in dense deposit disease and C3 glomerulonephritis is hyperactivity of the alternative complement pathway. Eculizumab, a monoclonal antibody that binds to C5 to prevent formation of the membrane attack complex, may prove beneficial. Design, setting, participants, & measurements In this open-label, proof of concept efficacy and safety study, six subjects with dense deposit disease or C3 glomerulonephritis were treated with eculizumab every other week for 1 year. All had proteinuria >1 g/d and/or AKI at enrollment. Subjects underwent biopsy before enrollment and repeat biopsy at the 1-year mark. Results The subjects included three patients with dense deposit disease (including one patient with recurrent dense deposit disease in allograft) and three patients with C3 glomerulonephritis (including two patients with recurrent C3 glomerulonephritis in allograft). Genetic and complement function testing revealed a mutation in CFH and MCP in one subject each, C3 nephritic factor in three subjects, and elevated levels of serum membrane attack complex in three subjects. After 12 months, two subjects showed significantly reduced serum creatinine, one subject achieved marked reduction in proteinuria, and one subject had stable laboratory parameters but histopathologic improvements. Elevated serum membrane attack complex levels normalized on therapy and paralleled improvements in creatinine and proteinuria. Conclusions Clinical and histopathologic data suggest a response to eculizumab in some but not all subjects with dense deposit disease and C3 glomerulonephritis. Elevation of serum membrane attack complex before treatment may predict response. Additional research is needed to define the subgroup of dense deposit disease/C3 glomerulonephritis patients in whom eculizumab therapy can be considered. PMID:22403278

  14. From cold to hot nuclear matter

    NASA Astrophysics Data System (ADS)

    Bratkovskaya, E. L.; Cassing, W.; Konchakovski, V. P.; Toneev, V. D.

    2015-11-01

    The dynamics of partons and hadrons in relativistic nucleus-nucleus collisions is analyzed within the Parton-Hadron-String Dynamics (PHSD) transport approach which is based on a dynamical quasiparticle model for the partonic phase (DQPM) including a dynamical hadronization scheme with covariant transition rates. The PHSD approach is applied to nucleus-nucleus collisions from FAIR/NICA to LHC energies. The traces of partonic interactions are found in particular in the directed and elliptic flow of hadrons and in their transverse mass spectra. Whereas at RHIC and LHC energies the dynamics is dominated by partonic degrees-of-freedom in the hot QGP, we find at FAIR/NICA energies a moderately hot but dense matter where chiral symmetry restoration and hadronic potentials appear to play a major role.

  15. Evolutionary models of rotating dense stellar systems: challenges in software and hardware

    NASA Astrophysics Data System (ADS)

    Fiestas, Jose

    2016-02-01

    We present evolutionary models of rotating self-gravitating systems (e.g. globular clusters, galaxy cores). These models are characterized by the presence of initial axisymmetry due to rotation. Central black hole seeds are alternatively included in our models, and black hole growth due to consumption of stellar matter is simulated until the central potential dominates the kinematics in the core. Goal is to study the long-term evolution (~ Gyr) of relaxed dense stellar systems, which deviate from spherical symmetry, their morphology and final kinematics. With this purpose, we developed a 2D Fokker-Planck analytical code, which results we confirm by detailed N-Body techniques, applying a high performance code, developed for GPU machines. We compare our models to available observations of galactic rotating globular clusters, and conclude that initial rotation modifies significantly the shape and lifetime of these systems, and can not be neglected in studying the evolution of globular clusters, and the galaxy itself.

  16. Framework for shape analysis of white matter fiber bundles.

    PubMed

    Glozman, Tanya; Bruckert, Lisa; Pestilli, Franco; Yecies, Derek W; Guibas, Leonidas J; Yeom, Kristen W

    2018-02-15

    Diffusion imaging coupled with tractography algorithms allows researchers to image human white matter fiber bundles in-vivo. These bundles are three-dimensional structures with shapes that change over time during the course of development as well as in pathologic states. While most studies on white matter variability focus on analysis of tissue properties estimated from the diffusion data, e.g. fractional anisotropy, the shape variability of white matter fiber bundle is much less explored. In this paper, we present a set of tools for shape analysis of white matter fiber bundles, namely: (1) a concise geometric model of bundle shapes; (2) a method for bundle registration between subjects; (3) a method for deformation estimation. Our framework is useful for analysis of shape variability in white matter fiber bundles. We demonstrate our framework by applying our methods on two datasets: one consisting of data for 6 normal adults and another consisting of data for 38 normal children of age 11 days to 8.5 years. We suggest a robust and reproducible method to measure changes in the shape of white matter fiber bundles. We demonstrate how this method can be used to create a model to assess age-dependent changes in the shape of specific fiber bundles. We derive such models for an ensemble of white matter fiber bundles on our pediatric dataset and show that our results agree with normative human head and brain growth data. Creating these models for a large pediatric longitudinal dataset may improve understanding of both normal development and pathologic states and propose novel parameters for the examination of the pediatric brain. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Dense Seismic Recordings of Two Surface-Detonated Chemical Explosions

    NASA Astrophysics Data System (ADS)

    Koper, K. D.; Hale, J. M.; Burlacu, R.; Goddard, K. J.; Trow, A.; Linville, L. M.; Stein, J. R.; Drobeck, D.; Leidig, M.

    2015-12-01

    In the summer of 2015 two controlled chemical explosions were carried out near Dugway, Utah. The 2 June 2015 explosion consisted of 30,000 lbs of ammonium nitrate fuel oil (ANFO) and the 22 July 2015 explosion consisted of 60,000 lbs of ANFO. The explosion centroids were 1-2 m above the Earth's surface and both created significant craters in the soft desert alluvium. To better understand the seismic source associated with surface explosions, we deployed an array of wireless, three-component, short-period (5 Hz corner frequency) seismometers for several days around each shot. For the first explosion, 46 receivers were deployed in a "lollipop" geometry that had a sparse ring at a radius of 1 km, and a dense stem with 100 m spacing for distances of 0.5-4.5 km. For the second explosion, 48 receivers were deployed similarly, but with a dense ring spaced in azimuthal increments of 10 degrees at a distance of 1 km, and a sparse stem (~500 m spacing) that extended to a distance of nearly 6 km. A rich variety of phases were recorded including direct P waves, refracted and reflected P waves, nearly monochromatic air-coupled Rayleigh waves, normally dispersed fundamental mode Rayleigh waves (Rg), primary airblast arrivals, some secondary airblast arrivals, and possibly tertiary airblast arrivals. There is also evidence of converted S waves on the radial components and possibly direct S energy on the radial and transverse components, although the transverse energy does not always possess a simple, coherent move-out with distance, implying that it might have a scattering origin. To aid in the phase identification, especially of the apparent SH and Love energy, we are currently performing tau-p, f-k, and particle motion analysis.

  18. Summer ammonia measurements in a densely populated Mediterranean city

    NASA Astrophysics Data System (ADS)

    Pandolfi, M.; Amato, F.; Reche, C.; Alastuey, A.; Otjes, R. P.; Blom, M. J.; Querol, X.

    2012-04-01

    Real-time measurements of ambient concentrations of gas-phase ammonia were performed in Barcelona (NE Spain) in summer between May and September 2011. Two measurement sites were selected: one in an urban background traffic-influenced area (UB) and the other in the historical city centre (CC). Levels of ammonia were higher at CC (5.6 ± 2.1 μg m-3 or 7.5 ± 2.8 ppbv) compared with UB (2.2 ± 1.0 μg m-3 or 2.9 ± 1.3 ppbv). This difference is attributed to the contribution from non-traffic sources such as waste containers, sewage systems, humans and open markets more dense in the densely populated historical city centre. Under high temperatures in summer these sources had the potential to increase the ambient levels of ammonia well above the urban-background-traffic-influenced UB measurement station. Measurements were used to assess major local emissions, sinks and diurnal evolution of NH3. The measured levels of NH3, especially high in the old city, may contribute to the high mean annual concentrations of secondary sulfate and nitrate measured in Barcelona compared with other cities in Spain affected by high traffic intensity. Ancillary measurements, including PM10, PM2.5, PM1 levels (Particulate Matter with aerodynamic diameter smaller than 10 μm, 2.5 μm, and 1 μm), gases and black carbon concentrations and meteorological data, were performed during the measurement campaign. The analysis of specific periods (3 special cases) during the campaign revealed that road traffic was a significant source of NH3. However, its effect was more evident at UB compared with CC where it was masked given the high levels of NH3 from non-traffic sources measured in the old city. The relationship between SO42- daily concentrations and gas-fraction ammonia (NH3/(NH3+NH4+)) revealed that the gas-to-phase partitioning (volatilization or ammonium salts formation) also played an important role in the evolution of NH3 concentration in summer in Barcelona.

  19. The numerical simulation study of hemodynamics of the new dense-mesh stent

    NASA Astrophysics Data System (ADS)

    Ma, Jiali; Yuan, Zhishan; Yu, Xuebao; Feng, Zhaowei; Miao, Weidong; Xu, Xueli; Li, Juntao

    2017-09-01

    The treatment of aortic aneurysm in new dense mesh stent is based on the principle of hemodynamic changes. But the mechanism is not yet very clear. This paper analyzed and calculated the hemodynamic situation before and after the new dense mesh stent implanting by the method of numerical simulation. The results show the dense mesh stent changed and impacted the blood flow in the aortic aneurysm. The changes include significant decrement of blood velocity, pressure and shear forces, while ensuring blood can supply branches, which means the new dense mesh stent's hemodynamic mechanism in the treatment of aortic aneurysm is clearer. It has very important significance in developing new dense mesh stent in order to cure aortic aneurysm.

  20. Kinetic simulations of gas breakdown in the dense plasma focus

    DOE PAGES

    Bennett, N.; Blasco, M.; Breeding, K.; ...

    2017-06-09

    We describe the first fully-kinetic, collisional, and electromagnetic simulations of the breakdown phase of a MA-scale dense plasma focus and are shown to agree with measured electrical characteristics, including breakdown time. In the model, avalanche ionization is driven by cathode electron emission and this results in incomplete gas breakdown along the insulator. This reinforces the importance of the conditioning process that creates a metallic layer on the insulator surface. The simulations, nonetheless, help explain the relationship between the gas pressure, the insulator length, and the coaxial gap width. In the past, researchers noted three breakdown patterns related to pressure. Simulationmore » and analytic results show that at low pressures, long ionization path lengths lead to volumetric breakdown, while high pressures lead to breakdown across the relatively small coaxial electrode gap. In an intermediate pressure regime, ionization path lengths are comparable to the insulator length which promotes ideal breakdown along the insulator surface.« less

  1. Model of the Phase Transition Mimicking the Pasta Phase in Cold and Dense Quark-Hadron Matter

    NASA Astrophysics Data System (ADS)

    Ayriyan, Alexander; Grigorian, Hovik

    2018-02-01

    A simple mixed phase model mimicking so-called "pasta" phases in the quarkhadron phase transition is developed and applied to static neutron stars for the case of DD2 type hadronic and NJL type quark matter models. The influence of the mixed phase on the mass-radius relation of the compact stars is investigated. Model parameters are chosen such that the results are in agreement with the mass-radius constraints.

  2. Sub-MeV bosonic dark matter, misalignment mechanism, and galactic dark matter halo luminosities

    NASA Astrophysics Data System (ADS)

    Yang, Qiaoli; Di, Haoran

    2017-04-01

    We explore a scenario that dark matter is a boson condensate created by the misalignment mechanism, in which a spin 0 boson (an axionlike particle) and a spin 1 boson (the dark photon) are considered, respectively. We find that although the sub-MeV dark matter boson is extremely stable, the huge number of dark matter particles in a galaxy halo makes the decaying signal detectable. A galaxy halo is a large structure bounded by gravity with a typical ˜1 012 solar mass, and the majority of its components are made of dark matter. For the axionlike particle case, it decays via ϕ →γ γ , therefore the photon spectrum is monochromatic. For the dark photon case, it is a three body decay A'→γ γ γ . However, we find that the photon spectrum is heavily peaked at M /2 and thus can facilitate observation. We also suggest a physical explanation for the three body decay spectrum by comparing the physics in the decay of orthopositronium. In addition, for both cases, the decaying photon flux can be measured for some regions of parameter space using current technologies.

  3. Dissipative dark matter and the Andromeda plane of satellites

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Randall, Lisa; Scholtz, Jakub, E-mail: randall@physics.harvard.edu, E-mail: jscholtz@physics.harvard.edu

    We show that dissipative dark matter can potentially explain the large observed mass to light ratio of the dwarf satellite galaxies that have been observed in the recently identified planar structure around Andromeda, which are thought to result from tidal forces during a galaxy merger. Whereas dwarf galaxies created from ordinary disks would be dark matter poor, dark matter inside the galactic plane not only provides a source of dark matter, but one that is more readily bound due to the dark matter's lower velocity. This initial N-body study shows that with a thin disk of dark matter inside themore » baryonic disk, mass-to-light ratios as high as O(90) can be generated when tidal forces pull out patches of sizes similar to the scales of Toomre instabilities of the dark disk. A full simulation will be needed to confirm this result.« less

  4. Characterizing Variability In Ohio River Natural Organic Matter

    EPA Science Inventory

    Surface water contains natural organic matter (NOM) which reacts with disinfectants creating disinfection byproducts (DBPs), some of which are USEPA regulated contaminants. Characterizing NOM can provide important insight on DBP formation and water treatment process adaptation t...

  5. Dynamic conductivity and plasmon profile of aluminum in the ultra-fast-matter regime

    NASA Astrophysics Data System (ADS)

    Dharma-wardana, M. W. C.

    2016-06-01

    We use an explicitly isochoric two-temperature theory to analyze recent x-ray laser scattering data for aluminum in the ultra-fast-matter (UFM) regime up to 6 eV. The observed surprisingly low conductivities are explained by including strong electron-ion scattering effects using the phase shifts calculated via the neutral-pseudo-atom model. The difference between the static conductivity for UFM-Al and equilibrium aluminum in the warm-dense matter state is clearly brought out by comparisons with available density-fucntional+molecular-dynamics simulations. Thus the applicability of the Mermin model to UFM is questioned. The static and dynamic conductivity, collision frequency, and the plasmon line shape, evaluated within the simplest Born approximation for UFM aluminum, are in good agreement with experiment.

  6. Mapping the dense scotoma and its enlargement in Stargardt disease

    PubMed Central

    Bernstein, Aryeh; Sunness, Janet S.; Applegate, Carol A.; Tegins, Elizabeth O.

    2016-01-01

    Purpose To describe the enlargement of the dense scotoma over time in Stargardt disease, and to highlight methodological issues in tracking enlargement. Methods Retrospective study of patients with full mapping of the border of the dense scotoma using the MP-1 for at least two visits. Results Fourteen eyes of 7 patients met this criterion. Patients had median of 3 visits (range 2 to 5), with median total f/u of 4.5 years (range 1.5-8). Mean baseline visual acuity was 20/56 (range 20/25-20/200), mean baseline dense scotoma area was 2.23mm2 (range 0.41-5.48), and mean dense scotoma enlargement rate was 1.36mm2/year (range 0.22-2.91). The younger patients tended to have more rapid loss of visual acuity, which tended to plateau when the VA was 20/100 or worse. The patients who developed Stargardt before age 20, and the single patient who developed Stargardt disease after age 40, had more rapid enlargement rates, with preservation of central vision in the oldest patient. The ability to precisely define the dense scotoma area was dependent upon the density location of the points tested; this led to significant variability in the assessment of the scotoma enlargement rate in 3 of the 7 patients. The dense scotoma was not described adequately by the extent of the homogeneous dark area on fundus autofluorescence imaging. Conclusion Microperimetry is necessary for mapping the scotoma in patients with Stargardt disease, since current imaging is not adequate. Standardized grid testing, plus a standardized procedure for refining the border of the dense scotoma, should allow more precise testing and longitudinal assessment of enlargement rates. PMID:26909568

  7. Critical point in the phase diagram of primordial quark-gluon matter from black hole physics

    NASA Astrophysics Data System (ADS)

    Critelli, Renato; Noronha, Jorge; Noronha-Hostler, Jacquelyn; Portillo, Israel; Ratti, Claudia; Rougemont, Romulo

    2017-11-01

    Strongly interacting matter undergoes a crossover phase transition at high temperatures T ˜1012 K and zero net-baryon density. A fundamental question in the theory of strong interactions, QCD, is whether a hot and dense system of quarks and gluons displays critical phenomena when doped with more quarks than antiquarks, where net-baryon number fluctuations diverge. Recent lattice QCD work indicates that such a critical point can only occur in the baryon dense regime of the theory, which defies a description from first principles calculations. Here we use the holographic gauge/gravity correspondence to map the fluctuations of baryon charge in the dense quark-gluon liquid onto a numerically tractable gravitational problem involving the charge fluctuations of holographic black holes. This approach quantitatively reproduces ab initio results for the lowest order moments of the baryon fluctuations and makes predictions for the higher-order baryon susceptibilities and also for the location of the critical point, which is found to be within the reach of heavy-ion collision experiments.

  8. Spark plasma sintering of highly dense fine-grained mineral aggregates

    NASA Astrophysics Data System (ADS)

    Koizumi, S.; Suzuki, T. S.; Sakka, Y.; Hiraga, T.

    2017-12-01

    To obtain highly dense and fine-grained mineral aggregates, which are suitable for laboratory measurements of their physical and chemical properties, we applied spark plasma sintering (SPS) to synthetic mineral powders and powders originated from naturally derived crystals. SPS is an emerging consolidation technique which has been applied to various metals and ceramics and rarely to geomaterials (e.g., Guignard et al., 2011). The technique uses spark plasma created by a pulse direct current during heat treatment of powders in a graphite die. It has been found that the technique provides better densification with little grain growth during sintering compared to a conventional sintering technique in many materials. To obtain ideal highly dense fine-grained materials, it is essential to prepare starting powders suitable for the sintering and also to find appropriate sintering conditions of applied uniaxial pressures, pulsed current patterns and heating rates. We prepared synthetic mineral powers through solid state reaction of source powders at high temperature well developed by our group (Koizumi et al. 2010). We also used jet milling at wet condition and subsequent elutriation to prepare olivine powders with sub-micron particle size and equiaxed particle shape. At heating rate of ≦10°C/min and an achievement of highest temperature of 1150°C, Fe-free olivine aggregate with average grain size of 200 nm with porosity of 0.003% was obtained. We also could obtain olivine aggregate, which was sintered from powders of Horoman peridotite, with average grain size of 500 nm and porosity of 0.2%. We will show results of other minerals including major rock forming minerals of the Earth's crust.

  9. Subject Matter Expert Workshop to Identify Cybersecurity ...

    EPA Pesticide Factsheets

    Report In recognition of the growing need to better address cyber risk and cyber management, the U.S. Environmental Protection Agency’s (EPA) National Homeland Security Research Center (NHSRC) held a Subject Matter Expert Workshop to Identify Cybersecurity Research Gaps and Needs of the Nation’s Water and Wastewater Systems Sector on March 30th and 31st, 2016, at the Ronald Reagan Building in Washington, D.C. The workshop was designed to create a forum for subject matter experts (SMEs) to exchange ideas and address important cybersecurity challenges facing the water sector.

  10. White matter integrity deficits in prefrontal-amygdala pathways in Williams syndrome.

    PubMed

    Avery, Suzanne N; Thornton-Wells, Tricia A; Anderson, Adam W; Blackford, Jennifer Urbano

    2012-01-16

    Williams syndrome is a neurodevelopmental disorder associated with significant non-social fears. Consistent with this elevated non-social fear, individuals with Williams syndrome have an abnormally elevated amygdala response when viewing threatening non-social stimuli. In typically-developing individuals, amygdala activity is inhibited through dense, reciprocal white matter connections with the prefrontal cortex. Neuroimaging studies suggest a functional uncoupling of normal prefrontal-amygdala inhibition in individuals with Williams syndrome, which might underlie both the extreme amygdala activity and non-social fears. This functional uncoupling might be caused by structural deficits in underlying white matter pathways; however, prefrontal-amygdala white matter deficits have yet to be explored in Williams syndrome. We used diffusion tensor imaging to investigate prefrontal-amygdala white matter integrity differences in individuals with Williams syndrome and typically-developing controls with high levels of non-social fear. White matter pathways between the amygdala and several prefrontal regions were isolated using probabilistic tractography. Within each pathway, we tested for between-group differences in three measures of white matter integrity: fractional anisotropy (FA), radial diffusivity (RD), and parallel diffusivity (λ(1)). Individuals with Williams syndrome had lower FA, compared to controls, in several of the prefrontal-amygdala pathways investigated, indicating a reduction in white matter integrity. Lower FA in Williams syndrome was explained by significantly higher RD, with no differences in λ(1), suggestive of lower fiber density or axon myelination in prefrontal-amygdala pathways. These results suggest that deficits in the structural integrity of prefrontal-amygdala white matter pathways might underlie the increased amygdala activity and extreme non-social fears observed in Williams syndrome. Copyright © 2011 Elsevier Inc. All rights reserved.

  11. Observations of strong ion-ion correlations in dense plasmas

    DOE PAGES

    Ma, T.; Fletcher, L.; Pak, A.; ...

    2014-04-24

    Using simultaneous spectrally, angularly, and temporally resolved x-ray scattering, we measure the pronounced ion-ion correlation peak in a strongly coupled plasma. Laser-driven shock-compressed aluminum at ~3× solid density is probed with high-energy photons at 17.9 keV created by molybdenum He-α emission in a laser-driven plasma source. The measured elastic scattering feature shows a well-pronounced correlation peak at a wave vector of k=4Å –1. The magnitude of this correlation peak cannot be described by standard plasma theories employing a linear screened Coulomb potential. Advanced models, including a strong short-range repulsion due to the inner structure of the aluminum ions are howevermore » in good agreement with the scattering data. These studies have demonstrated a new highly accurate diagnostic technique to directly measure the state of compression and the ion-ion correlations. Furthermore, we have since applied this new method in single-shot wave-number resolved S(k) measurements to characterize the physical properties of dense plasmas.« less

  12. Dynamics of dense direct-seeded stands of southern pines

    Treesearch

    J.C.G. Goelz

    2006-01-01

    Direct seeding of southern pines is an effective method of artificial regeneration, producing extremely dense stands when survival exceeds expectations. Long-term studies of dense direct-seeded stands provide ideal data for exploring development of stands as they approach the limit of maximum stand density. I present data from seven studies with ages of stands ranging...

  13. Laser Beat-Wave Magnetization of a Dense Plasma

    NASA Astrophysics Data System (ADS)

    Yates, Kevin; Hsu, Scott; Montgomery, David; Dunn, John; Langendorf, Samuel; Pollock, Bradley; Johnson, Timothy; Welch, Dale; Thoma, Carsten

    2017-10-01

    We present results from the first of a series of experiments to demonstrate and characterize laser beat-wave magnetization of a dense plasma, motivated by the desire to create high-beta targets with standoff for magneto-inertial fusion. The experiments are being conducted at the Jupiter Laser Facility (JLF) at LLNL. The experiment uses the JLF Janus 1 ω (1053 nm) beam and a standalone Nd:YAG (1064 nm) to drive the beat wave, and the Janus 2 ω (526.5 nm) beam to ionize/heat a gas-jet target as well as to provide Thomson-scattering (TS) measurements of the target density/temperature and scattered light from the beat wave. Streaked TS data captured electron-plasma-wave and ion-acoustic-wave features utilizing either nitrogen or helium gas jets. Effects of initial gas density as well as laser intensity on target have been measured, with electron densities ranging from 1E18 to 1E19 cm-3 with temperatures of tens to hundreds of eV, near the desired range for optimal field generation. LSP simulations were run to aid experimental design and data interpretation. LANL LDRD Program.

  14. Dense Plasma Focus Modeling

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Li, Hui; Li, Shengtai; Jungman, Gerard

    2016-08-31

    The mechanisms for pinch formation in Dense Plasma Focus (DPF) devices, with the generation of high-energy ions beams and subsequent neutron production over a relatively short distance, are not fully understood. Here we report on high-fidelity 2D and 3D numerical magnetohydrodynamic (MHD) simulations using the LA-COMPASS code to study the pinch formation dynamics and its associated instabilities and neutron production.

  15. Has the QCD critical point been signaled by observations at the BNL relativistic heavy ion collider?

    PubMed

    Lacey, Roy A; Ajitanand, N N; Alexander, J M; Chung, P; Holzmann, W G; Issah, M; Taranenko, A; Danielewicz, P; Stöcker, Horst

    2007-03-02

    The shear viscosity to entropy ratio (eta/s) is estimated for the hot and dense QCD matter created in Au+Au collisions at BNL Relativistic Heavy Ion Collider (square root[s_{NN}]=200 GeV). A very low value is found; eta/s approximately 0.1, which is close to the conjectured lower bound (1/4pi). It is argued that such a low value is indicative of thermodynamic trajectories for the decaying matter which lie close to the QCD critical end point.

  16. X-ray free-electron laser studies of dense plasmas

    NASA Astrophysics Data System (ADS)

    Vinko, Sam M.

    2015-10-01

    > The high peak brightness of X-ray free-electron lasers (FELs), coupled with X-ray optics enabling the focusing of pulses down to sub-micron spot sizes, provides an attractive route to generating high energy-density systems on femtosecond time scales, via the isochoric heating of solid samples. Once created, the fundamental properties of these plasmas can be studied with unprecedented accuracy and control, providing essential experimental data needed to test and benchmark commonly used theoretical models and assumptions in the study of matter in extreme conditions, as well as to develop new predictive capabilities. Current advances in isochoric heating and spectroscopic plasma studies on X-ray FELs are reviewed and future research directions and opportunities discussed.

  17. Predicted reentrant melting of dense hydrogen at ultra-high pressures

    PubMed Central

    Geng, Hua Y.; Wu, Q.

    2016-01-01

    The phase diagram of hydrogen is one of the most important challenges in high-pressure physics and astrophysics. Especially, the melting of dense hydrogen is complicated by dimer dissociation, metallization and nuclear quantum effect of protons, which together lead to a cold melting of dense hydrogen when above 500 GPa. Nonetheless, the variation of the melting curve at higher pressures is virtually uncharted. Here we report that using ab initio molecular dynamics and path integral simulations based on density functional theory, a new atomic phase is discovered, which gives an uplifting melting curve of dense hydrogen when beyond 2 TPa, and results in a reentrant solid-liquid transition before entering the Wigner crystalline phase of protons. The findings greatly extend the phase diagram of dense hydrogen, and put metallic hydrogen into the group of alkali metals, with its melting curve closely resembling those of lithium and sodium. PMID:27834405

  18. Development and Benchmarking of a Hybrid PIC Code For Dense Plasmas and Fast Ignition

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Witherspoon, F. Douglas; Welch, Dale R.; Thompson, John R.

    Radiation processes play an important role in the study of both fast ignition and other inertial confinement schemes, such as plasma jet driven magneto-inertial fusion, both in their effect on energy balance, and in generating diagnostic signals. In the latter case, warm and hot dense matter may be produced by the convergence of a plasma shell formed by the merging of an assembly of high Mach number plasma jets. This innovative approach has the potential advantage of creating matter of high energy densities in voluminous amount compared with high power lasers or particle beams. An important application of this technologymore » is as a plasma liner for the flux compression of magnetized plasma to create ultra-high magnetic fields and burning plasmas. HyperV Technologies Corp. has been developing plasma jet accelerator technology in both coaxial and linear railgun geometries to produce plasma jets of sufficient mass, density, and velocity to create such imploding plasma liners. An enabling tool for the development of this technology is the ability to model the plasma dynamics, not only in the accelerators themselves, but also in the resulting magnetized target plasma and within the merging/interacting plasma jets during transport to the target. Welch pioneered numerical modeling of such plasmas (including for fast ignition) using the LSP simulation code. Lsp is an electromagnetic, parallelized, plasma simulation code under development since 1995. It has a number of innovative features making it uniquely suitable for modeling high energy density plasmas including a hybrid fluid model for electrons that allows electrons in dense plasmas to be modeled with a kinetic or fluid treatment as appropriate. In addition to in-house use at Voss Scientific, several groups carrying out research in Fast Ignition (LLNL, SNL, UCSD, AWE (UK), and Imperial College (UK)) also use LSP. A collaborative team consisting of HyperV Technologies Corp., Voss Scientific LLC, FAR-TECH, Inc

  19. Signatures of dark radiation in neutrino and dark matter detectors

    NASA Astrophysics Data System (ADS)

    Cui, Yanou; Pospelov, Maxim; Pradler, Josef

    2018-05-01

    We consider the generic possibility that the Universe's energy budget includes some form of relativistic or semi-relativistic dark radiation (DR) with nongravitational interactions with standard model (SM) particles. Such dark radiation may consist of SM singlets or a nonthermal, energetic component of neutrinos. If such DR is created at a relatively recent epoch, it can carry sufficient energy to leave a detectable imprint in experiments designed to search for very weakly interacting particles: dark matter and underground neutrino experiments. We analyze this possibility in some generality, assuming that the interactive dark radiation is sourced by late decays of an unstable particle, potentially a component of dark matter, and considering a variety of possible interactions between the dark radiation and SM particles. Concentrating on the sub-GeV energy region, we derive constraints on different forms of DR using the results of the most sensitive neutrino and dark matter direct detection experiments. In particular, for interacting dark radiation carrying a typical momentum of ˜30 MeV /c , both types of experiments provide competitive constraints. This study also demonstrates that non-standard sources of neutrino emission (e.g., via dark matter decay) are capable of creating a "neutrino floor" for dark matter direct detection that is closer to current bounds than is expected from standard neutrino sources.

  20. Runaway electrons as a source of impurity and reduced fusion yield in the dense plasma focus

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lerner, Eric J.; Yousefi, Hamid R.

    2014-10-15

    Impurities produced by the vaporization of metals in the electrodes may be a major cause of reduced fusion yields in high-current dense plasma focus devices. We propose here that a major, but hitherto-overlooked, cause of such impurities is vaporization by runaway electrons during the breakdown process at the beginning of the current pulse. This process is sufficient to account for the large amount of erosion observed in many dense plasma focus devices on the anode very near to the insulator. The erosion is expected to become worse with lower pressures, typical of machines with large electrode radii, and would explainmore » the plateauing of fusion yield observed in such machines at higher peak currents. Such runaway electron vaporization can be eliminated by the proper choice of electrode material, by reducing electrode radii and thus increasing fill gas pressure, or by using pre-ionization to eliminate the large fields that create runaway electrons. If these steps are combined with monolithic electrodes to eliminate arcing erosion, large reductions in impurities and large increases in fusion yield may be obtained, as the I{sup 4} scaling is extended to higher currents.« less

  1. Ultrafast electron kinetics in short pulse laser-driven dense hydrogen

    DOE PAGES

    Zastrau, U.; Sperling, P.; Fortmann-Grote, C.; ...

    2015-09-25

    Dense cryogenic hydrogen is heated by intense femtosecond infrared laser pulses at intensities ofmore » $${10}^{15}-{10}^{16}\\;$$ W cm–2. Three-dimensional particle-in-cell (PIC) simulations predict that this heating is limited to the skin depth, causing an inhomogeneously heated outer shell with a cold core and two prominent temperatures of about $25$ and $$40\\;\\mathrm{eV}$$ for simulated delay times up to $$+70\\;\\mathrm{fs}$$ after the laser pulse maximum. Experimentally, the time-integrated emitted bremsstrahlung in the spectral range of 8–18 nm was corrected for the wavelength-dependent instrument efficiency. The resulting spectrum cannot be fit with a single temperature bremsstrahlung model, and the best fit is obtained using two temperatures of about 13 and $$30\\;$$eV. The lower temperatures in the experiment can be explained by missing energy-loss channels in the simulations, as well as the inclusion of hot, non-Maxwellian electrons in the temperature calculation. In conclusion, we resolved the time-scale for laser-heating of hydrogen, and PIC results for laser–matter interaction were successfully tested against the experiment data.« less

  2. Application of a Dense Gas Technique for Sterilizing Soft Biomaterials

    PubMed Central

    Karajanagi, Sandeep S.; Yoganathan, Roshan; Mammucari, Raffaella; Park, Hyoungshin; Cox, Julian; Zeitels, Steven M.; Langer, Robert; Foster, Neil R.

    2017-01-01

    Sterilization of soft biomaterials such as hydrogels is challenging because existing methods such as gamma irradiation, steam sterilization, or ethylene oxide sterilization, while effective at achieving high sterility assurance levels (SAL), may compromise their physicochemical properties and biocompatibility. New methods that effectively sterilize soft biomaterials without compromising their properties are therefore required. In this report, a dense-carbon dioxide (CO2)-based technique was used to sterilize soft polyethylene glycol (PEG)-based hydrogels while retaining their structure and physicochemical properties. Conventional sterilization methods such as gamma irradiation and steam sterilization severely compromised the structure of the hydrogels. PEG hydrogels with high water content and low elastic shear modulus (a measure of stiffness) were deliberately inoculated with bacteria and spores and then subjected to dense CO2. The dense CO2-based methods effectively sterilized the hydrogels achieving a SAL of 10−7 without compromising the viscoelastic properties, pH, water-content, and structure of the gels. Furthermore, dense CO2-treated gels were biocompatible and non-toxic when implanted subcutaneously in ferrets. The application of novel dense CO2-based methods to sterilize soft biomaterials has implications in developing safe sterilization methods for soft biomedical implants such as dermal fillers and viscosupplements. PMID:21337339

  3. The Relationship between the Dense Neutral and Diffuse Ionized Gas in the Thick Disks of Two Edge-on Spiral Galaxies

    NASA Astrophysics Data System (ADS)

    Rueff, Katherine M.; Howk, J. Christopher; Pitterle, Marissa; Hirschauer, Alec S.; Fox, Andrew J.; Savage, Blair D.

    2013-03-01

    We present high-resolution, optical images (BVI + Hα) of the multiphase interstellar medium (ISM) in the thick disks of the edge-on spiral galaxies NGC 4013 and NGC 4302. Our images from the Hubble Space Telescope (HST), Large Binocular Telescope, and WIYN 3.5 m telescope reveal an extensive population of filamentary dust absorption seen to z ~2-2.5 kpc. Many of these dusty thick disk structures have characteristics reminiscent of molecular clouds found in the Milky Way disk. Our Hα images show that the extraplanar diffuse ionized gas (DIG) in these galaxies is dominated by a smooth, diffuse component. The strongly filamentary morphologies of the dust absorption have no counterpart in the smoothly distributed Hα emission. We argue that the thick disk DIG and dust-bearing filaments trace physically distinct phases of the thick disk ISM, the latter tracing a dense, warm or cold neutral medium. The dense, dusty matter in the thick disks of spiral galaxies is largely tracing matter ejected from the thin disk via energetic feedback from massive stars. The high densities of the gas may be a result of converging gas flows. This dense material fuels some thick disk star formation, as evidenced by the presence of thick disk H II regions. Based on observations obtained with the NASA/ESA Hubble Space Telescope operated at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. Also, based on data acquired using the Large Binocular Telescope (LBT). The LBT is an international collaboration among institutions in the US, Italy, and Germany. LBT Corporation partners are the University of Arizona, on behalf of the Arizona University System; Instituto Nazionale do Astrofisica, Italy; LBT Beteiligungsgesellschaft, Germany, representing the Max Planck Society, the Astrophysical Institute of Potsdam, and Heidelberg University; Ohio State University, and the Research Corporation, on

  4. Creating Discursive Space for Religion and Spirituality in Universities: A Review Essay

    ERIC Educational Resources Information Center

    St. John, Edward P.; Parrish, Dan

    2012-01-01

    The secularization of higher education has created a complicated context for discourse about religion and spirituality in most public and some private universities. Yet the growing orientation toward spirituality and faith among undergraduates calls for a renewed openness to matters of beliefs and values in college classrooms, a topic addressed by…

  5. Densely Cratered Terrain Near the Terminator

    NASA Image and Video Library

    2011-08-16

    NASA Dawn spacecraft shows densely cratered terrain near Vesta terminator on August 6, 2011. This image was taken through the framing camera clear filter aboard the spacecraft. North is pointing towards the two oclock position.

  6. Acceptance procedures for dense-graded mixes

    DOT National Transportation Integrated Search

    2001-03-01

    Recent literature related to acceptance procedures for dense-graded mixtures is summarized. Current state of practice and development of acceptance procedures are reviewed. Many agencies are reducing the number of process control-related parameters i...

  7. X-ray absorption of a warm dense aluminum plasma created by an ultra-short laser pulse

    NASA Astrophysics Data System (ADS)

    Lecherbourg, L.; Renaudin, P.; Bastiani-Ceccotti, S.; Geindre, J.-P.; Blancard, C.; Cossé, P.; Faussurier, G.; Shepherd, R.; Audebert, P.

    2007-05-01

    Point-projection K-shell absorption spectroscopy has been used to measure absorption spectra of transient aluminum plasma created by an ultra-short laser pulse. The 1s-2p and 1s-3p absorption lines of weakly ionized aluminum were measured for an extended range of densities in a low-temperature regime. Independent plasma characterization was obtained using frequency domain interferometry diagnostic (FDI) that allows the interpretation of the absorption spectra in terms of spectral opacities. A detailed opacity code using the density and temperature inferred from the FDI reproduce the measured absorption spectra except in the last stage of the recombination phase.

  8. Characterizing urban hydrodynamic models in densely settled river-corridors: Lessons from Jakarta

    NASA Astrophysics Data System (ADS)

    Shaad, K.; Ninsalam, Y.; Padawangi, R.; Burlando, P.

    2016-12-01

    The nature and pace of urbanization in South and South-east Asia has created unique circumstances for the inter-action between social and ecological systems linked to water resources - with the growing density of population; frequent and extensive modification on the flood plain alongside governance challenges creating large segment of the settled regions exposed to water security issues and flooding risks. The densely-settled river corridor in Jakarta, with nearly 590 km of waterfront exposed to frequent flooding, captures the scale and complexity typical of these systems. Developing models that can help improve our insights into these urban areas remain a challenge. Here, we present our attempts to apply high-resolution aerial and ground based mapping methods, alongside shallow groundwater monitoring and household surveys, to characterize hydrodynamic models of varying complexity, for a 7 km stretch on the Ciliwung River in the center of Jakarta. We explore the uncertainty associated with obtaining "hydraulically representative" ground description and influence of representation of structures in flood propagation over the short-term, while linking it to the diffusive forcings from settlement acting on the floodplain-river interaction over the long-term. Connecting, thus, flooding with water availability and contamination, we speculate on the ability to scale these approaches and technologies beyond the limits of the test site.

  9. Physics of neutrino flavor transformation through matter-neutrino resonances

    NASA Astrophysics Data System (ADS)

    Wu, Meng-Ru; Duan, Huaiyu; Qian, Yong-Zhong

    2016-01-01

    In astrophysical environments such as core-collapse supernovae and neutron star-neutron star or neutron star-black hole mergers where dense neutrino media are present, matter-neutrino resonances (MNRs) can occur when the neutrino propagation potentials due to neutrino-electron and neutrino-neutrino forward scattering nearly cancel each other. We show that neutrino flavor transformation through MNRs can be explained by multiple adiabatic solutions similar to the Mikheyev-Smirnov-Wolfenstein mechanism. We find that for the normal neutrino mass hierarchy, neutrino flavor evolution through MNRs can be sensitive to the shape of neutrino spectra and the adiabaticity of the system, but such sensitivity is absent for the inverted hierarchy.

  10. Do we live in the universe successively dominated by matter and antimatter?

    NASA Astrophysics Data System (ADS)

    Hajdukovic, Dragan Slavkov

    2011-08-01

    We wonder if a cyclic universe may be dominated alternatively by matter and antimatter. Such a scenario demands a mechanism for transformation of matter to antimatter (or antimatter to matter) during the final stage of a big crunch. By giving an example, we have shown that in principle such a mechanism is possible. Our mechanism is based on a hypothetical repulsion between matter and antimatter, existing at least deep inside the horizon of a black hole. When universe is reduced to a supermassive black hole of a small size, a very strong field of the conjectured force might create (through a Schwinger type mechanism) particle-antiparticle pairs from the quantum vacuum. The amount of antimatter created from the vacuum is equal to the decrease of mass of the black hole and violently repelled from it. When the size of the black hole is sufficiently small, the creation of antimatter may become so fast, that matter of our Universe might be transformed to antimatter in a fraction of second. Such a fast conversion of matter into antimatter may look as a Big Bang. Our mechanism prevents a singularity; a new cycle might start with an initial size more than 30 orders of magnitude greater than the Planck length, suggesting that there is no need for inflationary scenario in Cosmology. In addition, there is no need to invoke CP violation for explanation of matter-antimatter asymmetry. Simply, our present day Universe is dominated by matter, because the previous universe was dominated by antimatter.

  11. Creating healthy workplaces: what every nurse can do.

    PubMed

    Hamilton, Jane Meier

    2007-06-01

    Strong, proactive people focus their efforts, time, and energy on that which they control. Your co-workers' behavior can influence you, but never control you. Neither do you control your colleagues. No matter what your role or practice setting, or your level of power or experience, you do control your own behavior, and can thereby influence others in your workplace. Focus on yourself and how you behave at work. By choosing constructive, collaborative, respectful ways of interacting, every nurse can be instrumental in creating healthy workplaces.

  12. The Green Bank Ammonia Survey: Dense Cores under Pressure in Orion A

    NASA Astrophysics Data System (ADS)

    Kirk, Helen; Friesen, Rachel K.; Pineda, Jaime E.; Rosolowsky, Erik; Offner, Stella S. R.; Matzner, Christopher D.; Myers, Philip C.; Di Francesco, James; Caselli, Paola; Alves, Felipe O.; Chacón-Tanarro, Ana; Chen, How-Huan; Chun-Yuan Chen, Michael; Keown, Jared; Punanova, Anna; Seo, Young Min; Shirley, Yancy; Ginsburg, Adam; Hall, Christine; Singh, Ayushi; Arce, Héctor G.; Goodman, Alyssa A.; Martin, Peter; Redaelli, Elena

    2017-09-01

    We use data on gas temperature and velocity dispersion from the Green Bank Ammonia Survey and core masses and sizes from the James Clerk Maxwell Telescope Gould Belt Survey to estimate the virial states of dense cores within the Orion A molecular cloud. Surprisingly, we find that almost none of the dense cores are sufficiently massive to be bound when considering only the balance between self-gravity and the thermal and non-thermal motions present in the dense gas. Including the additional pressure binding imposed by the weight of the ambient molecular cloud material and additional smaller pressure terms, however, suggests that most of the dense cores are pressure-confined.

  13. PHOTOCHEMICAL HEATING OF DENSE MOLECULAR GAS

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Glassgold, A. E.; Najita, J. R.

    2015-09-10

    Photochemical heating is analyzed with an emphasis on the heating generated by chemical reactions initiated by the products of photodissociation and photoionization. The immediate products are slowed down by collisions with the ambient gas and then heat the gas. In addition to this direct process, heating is also produced by the subsequent chemical reactions initiated by these products. Some of this chemical heating comes from the kinetic energy of the reaction products and the rest from collisional de-excitation of the product atoms and molecules. In considering dense gas dominated by molecular hydrogen, we find that the chemical heating is sometimesmore » as large, if not much larger than, the direct heating. In very dense gas, the total photochemical heating approaches 10 eV per photodissociation (or photoionization), competitive with other ways of heating molecular gas.« less

  14. Relating quantum discord with the quantum dense coding capacity

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wang, Xin; Qiu, Liang, E-mail: lqiu@cumt.edu.cn; Li, Song

    2015-01-15

    We establish the relations between quantum discord and the quantum dense coding capacity in (n + 1)-particle quantum states. A necessary condition for the vanishing discord monogamy score is given. We also find that the loss of quantum dense coding capacity due to decoherence is bounded below by the sum of quantum discord. When these results are restricted to three-particle quantum states, some complementarity relations are obtained.

  15. The Transition from Diffuse to Dense Gas in Herschel Dust Emission Maps

    NASA Astrophysics Data System (ADS)

    Goldsmith, Paul

    Dense cores in dark clouds are the sites where young stars form. These regions manifest as relatively small (<0.1pc) pockets of cold and dense gas. If we wish to understand the star formation process, we have to understand the physical conditions in dense cores. This has been a main aim of star formation research in the past decade. Today, we do indeed possess a good knowledge of the density and velocity structure of cores, as well as their chemical evolution and physical lifetime. However, we do not understand well how dense cores form out of the diffuse gas clouds surrounding them. It is crucial that we constrain the relationship between dense cores and their environment: if we only understand dense cores, we may be able to understand how individual stars form --- but we would not know how the star forming dense cores themselves come into existence. We therefore propose to obtain data sets that reveal both dense cores and the clouds containing them in the same map. Based on these maps, we will study how dense cores form out of their natal clouds. Since cores form stars, this knowledge is crucial for the development of a complete theoretical and observational understanding of the formation of stars and their planets, as envisioned in NASA's Strategic Science Plan. Fortunately, existing archival data allow to derive exactly the sort of maps we need for our analysis. Here, we describe a program that exclusively builds on PACS and SPIRE dust emission imaging data from the NASA-supported Herschel mission. The degree-sized wide-field Herschel maps of the nearby (<260pc) Polaris Flare and Aquila Rift clouds are ideal for our work. They permit to resolve dense cores (<0.1pc), while the maps also reveal large-scale cloud structure (5pc and larger). We will generate column density maps from these dust emission maps and then run a tree-based hierarchical multi-scale structure analysis on them. Only this procedure permits to exploit the full potential of the maps: we will

  16. Under the sword of Damocles: plausible regeneration of dark matter cusps at the smallest galactic scales

    NASA Astrophysics Data System (ADS)

    Laporte, Chervin F. P.; Peñarrubia, Jorge

    2015-04-01

    We study the evolution of the dark matter (DM) halo profiles of dwarf galaxies driven by the accretion of DM substructures through controlled N-body experiments. Our initial conditions assume that early supernova feedback erases the primordial DM cusps of haloes with z = 0 masses of 109 - 1010 M⊙. The orbits and masses of the infalling substructures are borrowed from the Aquarius cosmological simulations. Our experiments show that a fraction of haloes that undergo 1:3 down to 1:30 mergers are susceptible to reform a DM cusp by z ≈ 0. Cusp regrowth is driven by the accretion of DM substructures that are dense enough to reach the central regions of the main halo before being tidally disrupted. The infall of substructures on the mean of the reported mass-concentration relation and a mass ratio above 1:6 systematically leads to cusp regrowth. Substructures with 1:6-1:8, and 1:8-1:30 only reform DM cusps if their densities are 1σ and 2σ above the mean, respectively. The merging time-scales of these dense, low-mass substructures is relatively long (5 - 11 Gyr), which may pose a time-scale problem for the longevity of DM cores in dwarfs galaxies and possibly explain the existence of dense dwarfs-like Draco. These results suggest that within cold dark matter a non-negligible level of scatter in the mass profiles of galactic haloes acted on by feedback is to be expected given the stochastic mass accretion histories of low-mass haloes and the diverse star formation histories observed in the Local Group dwarfs.

  17. Kinetic Simulations of Dense Plasma Focus Breakdown

    NASA Astrophysics Data System (ADS)

    Schmidt, A.; Higginson, D. P.; Jiang, S.; Link, A.; Povilus, A.; Sears, J.; Bennett, N.; Rose, D. V.; Welch, D. R.

    2015-11-01

    A dense plasma focus (DPF) device is a type of plasma gun that drives current through a set of coaxial electrodes to assemble gas inside the device and then implode that gas on axis to form a Z-pinch. This implosion drives hydrodynamic and kinetic instabilities that generate strong electric fields, which produces a short intense pulse of x-rays, high-energy (>100 keV) electrons and ions, and (in deuterium gas) neutrons. A strong factor in pinch performance is the initial breakdown and ionization of the gas along the insulator surface separating the two electrodes. The smoothness and isotropy of this ionized sheath are imprinted on the current sheath that travels along the electrodes, thus making it an important portion of the DPF to both understand and optimize. Here we use kinetic simulations in the Particle-in-cell code LSP to model the breakdown. Simulations are initiated with neutral gas and the breakdown modeled self-consistently as driven by a charged capacitor system. We also investigate novel geometries for the insulator and electrodes to attempt to control the electric field profile. The initial ionization fraction of gas is explored computationally to gauge possible advantages of pre-ionization which could be created experimentally via lasers or a glow-discharge. Prepared by LLNL under Contract DE-AC52-07NA27344.

  18. The capture of attention by entirely irrelevant pictures of calorie-dense foods.

    PubMed

    Cunningham, Corbin A; Egeth, Howard E

    2018-04-01

    Inborn preference for palatable energy-dense food is thought to be an evolutionary adaptation. One way this preference manifests itself is through the control of visual attention. In the present study, we investigated how attentional capture is influenced by changes in naturally occurring goal-states, in this case desire for energy-dense foods (typically high fat and/or high sugar). We demonstrate that even when distractors are entirely irrelevant, participants were significantly more distracted by energy-dense foods compared with non-food objects and even low-energy foods. Additionally, we show the lability of these goal-states by having a separate set of participants consume a small amount of calorie-dense food prior to the task. The amount of distraction by the energy-dense food images in this case was significantly reduced and no different than distraction by images of low-energy foods and images of non-food objects. While naturally occurring goal-states can be difficult to ignore, they also are highly flexible.

  19. A quasi-dense matching approach and its calibration application with Internet photos.

    PubMed

    Wan, Yanli; Miao, Zhenjiang; Wu, Q M Jonathan; Wang, Xifu; Tang, Zhen; Wang, Zhifei

    2015-03-01

    This paper proposes a quasi-dense matching approach to the automatic acquisition of camera parameters, which is required for recovering 3-D information from 2-D images. An affine transformation-based optimization model and a new matching cost function are used to acquire quasi-dense correspondences with high accuracy in each pair of views. These correspondences can be effectively detected and tracked at the sub-pixel level in multiviews with our neighboring view selection strategy. A two-layer iteration algorithm is proposed to optimize 3-D quasi-dense points and camera parameters. In the inner layer, different optimization strategies based on local photometric consistency and a global objective function are employed to optimize the 3-D quasi-dense points and camera parameters, respectively. In the outer layer, quasi-dense correspondences are resampled to guide a new estimation and optimization process of the camera parameters. We demonstrate the effectiveness of our algorithm with several experiments.

  20. Ionic structures and transport properties of hot dense W and U plasmas

    NASA Astrophysics Data System (ADS)

    Hou, Yong; Yuan, Jianmin

    2016-10-01

    We have combined the average-atom model with the hyper-netted chain approximation (AAHNC) to describe the electronic and ionic structure of uranium and tungsten in the hot dense matter regime. When the electronic structure is described within the average-atom model, the effects of others ions on the electronic structure are considered by the correlation functions. And the ionic structure is calculated though using the hyper-netted chain (HNC) approximation. The ion-ion pair potential is calculated using the modified Gordon-Kim model based on the electronic density distribution in the temperature-depended density functional theory. And electronic and ionic structures are determined self-consistently. On the basis of the ion-ion pair potential, we perform the classical (CMD) and Langevin (LMD) molecular dynamics to simulate the ionic transport properties, such as ionic self-diffusion and shear viscosity coefficients, through the ionic velocity correlation functions. Due that the free electrons become more and more with increasing the plasma temperature, the influence of the electron-ion collisions on the transport properties become more and more important.

  1. Developing Cost-Effective Dense Continuous SDC Barrier Layers for SOFCs

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Nguyen, Hoang Viet P.; Hardy, John S.; Coyle, Christopher A.

    Significantly improved performance during electrochemical testing of a cell with a dense continuous pulsed laser deposited (PLD) samarium doped ceria (SDC) layer spurred investigations into the fabrication of dense continuous SDC barrier layers by means of cost-effective deposition using screen printing which is amenable to industrial production of SOFCs. Many approaches to improve the SDC density have been explored including the use of powder with reduced particle sizes, inks with increased solids loading, and doping with sintering aids (1). In terms of sintering aids, dopants like Mo or binary systems of Mo+Cu or Fe+Co greatly enhance SDC sinterability. In fact,more » adding dopants to a screen printed, prefired, porous SDC layer made it possible to achieve a dense continuous barrier layer atop the YSZ electrolyte without sintering above 1200°C. Although the objective of fabricating a dense continuous layer was achieved, additional studies have been initiated to improve the cell performance. Underlying issues with constrained sintering and dopant-enhanced ceria-zirconia solid solubility are also addressed in this paper.« less

  2. Thermodynamics of cosmological matter creation.

    PubMed

    Prigogine, I; Geheniau, J; Gunzig, E; Nardone, P

    1988-10-01

    A type of cosmological history that includes large-scale entropy production is proposed. These cosmologies are based on reinterpretation of the matter-energy stress tensor in Einstein's equations. This modifies the usual adiabatic energy conservation laws, thereby including irreversible matter creation. This creation corresponds to an irreversible energy flow from the gravitational field to the created matter constituents. This point of view results from consideration of the thermodynamics of open systems in the framework of cosmology. It is shown that the second law of thermodynamics requires that space-time transforms into matter, while the inverse transformation is forbidden. It appears that the usual initial singularity associated with the big bang is structurally unstable with respect to irreversible matter creation. The corresponding cosmological history therefore starts from an instability of the vacuum rather than from a singularity. This is exemplified in the framework of a simple phenomenological model that leads to a three-stage cosmology: the first drives the cosmological system from the initial instability to a de Sitter regime, and the last connects with the usual matter-radiation Robertson-Walker universe. Matter as well as entropy creation occurs during the first two stages, while the third involves the traditional cosmological evolution. A remarkable fact is that the de Sitter stage appears to be an attractor independent of the initial fluctuation. This is also the case for all the physical predictions involving the present Robertson-Walker universe. Most results obtained previously, in the framework of quantum field theory, can now be obtained on a macroscopic basis. It is shown that this description leads quite naturally to the introduction of primeval black holes as the intermediate stage between the Minkowski vacuum and the present matter-radiation universe. The instability at the origin of the universe is the result of fluctuations of the

  3. The Green Bank Ammonia Survey: Dense Cores under Pressure in Orion A

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kirk, Helen; Di Francesco, James; Friesen, Rachel K.

    We use data on gas temperature and velocity dispersion from the Green Bank Ammonia Survey and core masses and sizes from the James Clerk Maxwell Telescope Gould Belt Survey to estimate the virial states of dense cores within the Orion A molecular cloud. Surprisingly, we find that almost none of the dense cores are sufficiently massive to be bound when considering only the balance between self-gravity and the thermal and non-thermal motions present in the dense gas. Including the additional pressure binding imposed by the weight of the ambient molecular cloud material and additional smaller pressure terms, however, suggests thatmore » most of the dense cores are pressure-confined.« less

  4. Rheology of dense suspensions of non colloidal particles

    NASA Astrophysics Data System (ADS)

    Guazzelli, Élisabeth

    2017-06-01

    Dense suspensions are materials with broad applications both in industrial processes (e.g. waste disposal, concrete, drilling muds, metalworking chip transport, and food processing) and in natural phenomena (e.g. flows of slurries, debris, and lava). Despite its long research history and its practical relevance, the mechanics of dense suspensions remain poorly understood. The major difficulty is that the grains interact both by hydrodynamic interactions through the liquid and by mechanical contact. These systems thus belong to an intermediate regime between pure suspensions and granular flows. We show that we can unify suspension and granular rheology under a common framework by transferring the frictional approach of dry granular media to wet suspensions of spherical particles. We also discuss non-Newtonian behavior such as normal-stress differences and shear-induced migration. Beyond the classical problem of dense suspension of hard spheres which is far from being completely resolved, there are also entirely novel avenues of study concerning more complex mixtures of particles and fluids such as those involving other types of particles (e.g. fibers) or non-Newtonian fluids that we will also address.

  5. An extended GS method for dense linear systems

    NASA Astrophysics Data System (ADS)

    Niki, Hiroshi; Kohno, Toshiyuki; Abe, Kuniyoshi

    2009-09-01

    Davey and Rosindale [K. Davey, I. Rosindale, An iterative solution scheme for systems of boundary element equations, Internat. J. Numer. Methods Engrg. 37 (1994) 1399-1411] derived the GSOR method, which uses an upper triangular matrix [Omega] in order to solve dense linear systems. By applying functional analysis, the authors presented an expression for the optimum [Omega]. Moreover, Davey and Bounds [K. Davey, S. Bounds, A generalized SOR method for dense linear systems of boundary element equations, SIAM J. Comput. 19 (1998) 953-967] also introduced further interesting results. In this note, we employ a matrix analysis approach to investigate these schemes, and derive theorems that compare these schemes with existing preconditioners for dense linear systems. We show that the convergence rate of the Gauss-Seidel method with preconditioner PG is superior to that of the GSOR method. Moreover, we define some splittings associated with the iterative schemes. Some numerical examples are reported to confirm the theoretical analysis. We show that the EGS method with preconditioner produces an extremely small spectral radius in comparison with the other schemes considered.

  6. Measuring distance through dense weighted networks: The case of hospital-associated pathogens

    PubMed Central

    Smieszek, Timo; Henderson, Katherine L.; Johnson, Alan P.

    2017-01-01

    Hospital networks, formed by patients visiting multiple hospitals, affect the spread of hospital-associated infections, resulting in differences in risks for hospitals depending on their network position. These networks are increasingly used to inform strategies to prevent and control the spread of hospital-associated pathogens. However, many studies only consider patients that are received directly from the initial hospital, without considering the effect of indirect trajectories through the network. We determine the optimal way to measure the distance between hospitals within the network, by reconstructing the English hospital network based on shared patients in 2014–2015, and simulating the spread of a hospital-associated pathogen between hospitals, taking into consideration that each intermediate hospital conveys a delay in the further spread of the pathogen. While the risk of transferring a hospital-associated pathogen between directly neighbouring hospitals is a direct reflection of the number of shared patients, the distance between two hospitals far-away in the network is determined largely by the number of intermediate hospitals in the network. Because the network is dense, most long distance transmission chains in fact involve only few intermediate steps, spreading along the many weak links. The dense connectivity of hospital networks, together with a strong regional structure, causes hospital-associated pathogens to spread from the initial outbreak in a two-step process: first, the directly surrounding hospitals are affected through the strong connections, second all other hospitals receive introductions through the multitude of weaker links. Although the strong connections matter for local spread, weak links in the network can offer ideal routes for hospital-associated pathogens to travel further faster. This hold important implications for infection prevention and control efforts: if a local outbreak is not controlled in time, colonised patients will

  7. Creating an AI modeling application for designers and developers

    NASA Astrophysics Data System (ADS)

    Houlette, Ryan; Fu, Daniel; Jensen, Randy

    2003-09-01

    Simulation developers often realize an entity's AI by writing a program that exhibits the intended behavior. These behaviors are often the product of design documents written by designers. These individuals, while possessing a vast knowledge of the subject matter, might not have any programming knowledge whatsoever. To address this disconnect between design and subsequent development, we have created an AI application whereby a designer or developer sketches an entity's AI using a graphical "drag and drop" interface to quickly articulate behavior using a UML-like representation of state charts. Aside from the design-level benefits, the application also features a runtime engine that takes the application's data as input along with a simulation or game interface, and makes the AI operational. We discuss our experience in creating such an application for both designer and developer.

  8. Possible Climate Change Influences on Continued Reduction of Dense Fog in Southern California

    NASA Astrophysics Data System (ADS)

    Ladochy, S.; Witiw, M.

    2010-07-01

    Dense fog appears to be decreasing in many parts of the world, especially in cities. An earlier study showed that dense fog (visibility < 400 m) was disappearing in the urban southern California area as well. Using hourly data from 1948 to the present, we looked at the relationship between fog events and contributing factors in the region along with trends over time. We showed that the decrease in dense fog events could be explained mainly by declining particulate levels, Pacific SSTs, and increased urban warming. Dense fog is most prevalent along the coast and decreases rapidly inland, so the influence of the Pacific should be large. In particular, the Pacific Decadal Oscillation (PDO) and the Southern Oscillation signals can be seen in fog frequencies as well as in the contributing factors. Results show a decrease in the occurrence of dense fog at two airports in close proximity to the Pacific Ocean, LAX and LGB. Occurrence of the frequency of low visibilities at these two locations was highly correlated with the phases of the PDO. While examining data from LAX, we saw a frequency of dense fog that reached over 300 hours in 1950, but occurrence was down to zero in 1997. Since 1997, there has been a bit of a recovery with both 2008 and 2009 recording over 30 hours of dense fog each. In the present study, we continue to examine the relationships that control the frequency of dense fog in coastal southern California. To remove urban influence, we also included Vandenberg Air Force Base, located in a relatively sparsely populated area. While particulates, urban heat island and Pacific SSTs are all contributing factors, we now speculate on the direct and indirect influences of climate change on continued decreases in dense fog. Case studies of local and regional dense fog in southern California point to the importance of strong, low inversions and to a lesser contributor, Santa Ana winds. Both are associated with large-scale atmospheric circulation patterns, which

  9. Cancer incidence in urban, rural, and densely populated districts close to core cities in Bavaria, Germany.

    PubMed

    Radespiel-Tröger, M; Geiss, K; Twardella, D; Maier, W; Meyer, M

    2018-02-01

    An ecologic study on the level of districts was performed to evaluate the possible association between district type and risk of cancer in Bavaria, Southern Germany. Cancer incidence data for the years 2003-2012 were obtained from the population-based cancer registry Bavaria according to sex and cancer site. Data on district type, socio-economic area deprivation, particulate matter exposure, tobacco consumption, and alcohol consumption were obtained from publicly available sources. The possible association between district type and cancer risk adjusted for age, socio-economic area deprivation, particulate matter exposure, tobacco consumption, and alcohol consumption was evaluated using multivariable multi-level negative binomial regression. We found a significantly reduced cancer risk in densely populated districts close to core cities and/or rural districts compared to core cities with respect to the cancer sites mouth and pharynx (women only), liver (both sexes), larynx (both sexes), lung (both sexes), melanoma of the skin (both sexes), mesothelioma (men only), connective and soft tissue (both sexes), corpus uteri, other urinary tract (men only), urinary bladder (both sexes), and non-Hodgkin lymphoma (both sexes). Our findings require further monitoring. Since the apparently increased cancer risk in core cities may be related to lifestyle factors, preventive measures against lifestyle-related cancer could be specifically targeted at populations in deprived core cities.

  10. Quantum Cause of Gravity Waves and Dark Matter

    NASA Astrophysics Data System (ADS)

    Goradia, Shantilal; Goradia Team

    2016-09-01

    Per Einstein's theory mass tells space how to curve and space tells mass how to move. How do they tell''? The question boils down to information created by quantum particles blinking ON and OFF analogous to `Ying and Yang' or some more complex ways that may include dark matter. If not, what creates curvature of space-time? Consciousness, dark matter, quantum physics, uncertainty principle, constants of nature like strong coupling, fine structure constant, cosmological constant introduced by Einstein, information, gravitation etc. are fundamentally consequences of that ONE TOE. Vedic philosophers, who impressed Schrodinger so much, called it ATMA split in the categories of AnuAtma (particle soul), JivAtma (life soul) and ParamAtma (Omnipresent soul) which we relate to quantum physics, biology and cosmology. There is no separate TOE for any one thing. The long range relativistic propagations of the strong and weak couplings of the microscopic black holes in are just gravity waves. What else could they be?

  11. Dark Matter Hairs Around Earth -- Close-up

    NASA Image and Video Library

    2015-11-23

    This illustration shows Earth surrounded by filaments of dark matter called "hairs," which are proposed in a study in the Astrophysical Journal by Gary Prézeau of NASA's Jet Propulsion Laboratory, Pasadena, California. A hair is created when a stream of dark matter particles goes through the planet. According to simulations, the hair is densest at a point called the "root." When particles of a dark matter stream pass through the core of Earth, they form a hair whose root has a particle density about a billion times greater than average. The hairs in this illustration are not to scale. Simulations show that the roots of such hairs can be 600,000 miles (1 million kilometers) from Earth, while Earth's radius is only about 4,000 miles (6,400 kilometers). http://photojournal.jpl.nasa.gov/catalog/PIA20177

  12. Summer ammonia measurements in a densely populated Mediterranean city

    NASA Astrophysics Data System (ADS)

    Pandolfi, M.; Amato, F.; Reche, C.; Alastuey, A.; Otjes, R. P.; Blom, M. J.; Querol, X.

    2012-08-01

    Real-time measurements of ambient concentrations of gas-phase ammonia (NH3) were performed in Barcelona (NE Spain) in summer between May and September 2011. Two measurement sites were selected: one in an urban background traffic-influenced area (UB) and the other in the historical city centre (CC). Levels of NH3 were higher at CC (5.6 ± 2.1 μg m-3 or 7.5 ± 2.8 ppbv) compared with UB (2.2 ± 1.0 μg m-3 or 2.9 ± 1.3 ppbv). This difference is attributed to the contribution from non-traffic sources such as waste containers, sewage systems, humans and open markets more dense in the densely populated historical city centre. Under high temperatures in summer these sources had the potential to increase the ambient levels of NH3 well above the urban-background-traffic-influenced UB measurement station. Measurements were used to assess major local emissions, sinks and diurnal evolution of NH3. The measured levels of NH3, especially high in the old city, may contribute to the high mean annual concentrations of secondary sulfate and nitrate measured in Barcelona compared with other cities in Spain affected by high traffic intensity. Ancillary measurements, including PM10, PM2.5, PM1 levels (Particulate Matter with aerodynamic diameter smaller than 10 μm, 2.5 μm, and 1 μm), gases and black carbon concentrations and meteorological data, were performed during the measurement campaign. The analysis of specific periods (3 special cases) during the campaign revealed that road traffic was a significant source of NH3. However, its effect was more evident at UB compared with CC where it was masked given the high levels of NH3 from non-traffic sources measured in the old city. The relationship between SO42- daily concentrations and gas-fraction ammonia (NH3/(NH3 + NH4+)) revealed that the gas-to-particle phase partitioning (volatilization or ammonium salts formation) also played an important role in the evolution of NH3 concentration in summer in Barcelona.

  13. Dense Gas, Dynamical Equilibrium Pressure, and Star Formation in Nearby Star-forming Galaxies

    NASA Astrophysics Data System (ADS)

    Gallagher, Molly J.; Leroy, Adam K.; Bigiel, Frank; Cormier, Diane; Jiménez-Donaire, María J.; Ostriker, Eve; Usero, Antonio; Bolatto, Alberto D.; García-Burillo, Santiago; Hughes, Annie; Kepley, Amanda A.; Krumholz, Mark; Meidt, Sharon E.; Meier, David S.; Murphy, Eric J.; Pety, Jérôme; Rosolowsky, Erik; Schinnerer, Eva; Schruba, Andreas; Walter, Fabian

    2018-05-01

    We use new ALMA observations to investigate the connection between dense gas fraction, star formation rate (SFR), and local environment across the inner region of four local galaxies showing a wide range of molecular gas depletion times. We map HCN (1–0), HCO+ (1–0), CS (2–1), 13CO (1–0), and C18O (1–0) across the inner few kiloparsecs of each target. We combine these data with short-spacing information from the IRAM large program EMPIRE, archival CO maps, tracers of stellar structure and recent star formation, and recent HCN surveys by Bigiel et al. and Usero et al. We test the degree to which changes in the dense gas fraction drive changes in the SFR. {I}HCN}/{I}CO} (tracing the dense gas fraction) correlates strongly with I CO (tracing molecular gas surface density), stellar surface density, and dynamical equilibrium pressure, P DE. Therefore, {I}HCN}/{I}CO} becomes very low and HCN becomes very faint at large galactocentric radii, where ratios as low as {I}HCN}/{I}CO}∼ 0.01 become common. The apparent ability of dense gas to form stars, {{{Σ }}}SFR}/{{{Σ }}}dense} (where Σdense is traced by the HCN intensity and the star formation rate is traced by a combination of Hα and 24 μm emission), also depends on environment. {{{Σ }}}SFR}/{{{Σ }}}dense} decreases in regions of high gas surface density, high stellar surface density, and high P DE. Statistically, these correlations between environment and both {{{Σ }}}SFR}/{{{Σ }}}dense} and {I}HCN}/{I}CO} are stronger than that between apparent dense gas fraction ({I}HCN}/{I}CO}) and the apparent molecular gas star formation efficiency {{{Σ }}}SFR}/{{{Σ }}}mol}. We show that these results are not specific to HCN.

  14. THE JCMT GOULD BELT SURVEY: DENSE CORE CLUSTERS IN ORION A

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lane, J.; Kirk, H.; Johnstone, D.

    The Orion A molecular cloud is one of the most well-studied nearby star-forming regions, and includes regions of both highly clustered and more dispersed star formation across its full extent. Here, we analyze dense, star-forming cores identified in the 850 and 450 μ m SCUBA-2 maps from the JCMT Gould Belt Legacy Survey. We identify dense cores in a uniform manner across the Orion A cloud and analyze their clustering properties. Using two independent lines of analysis, we find evidence that clusters of dense cores tend to be mass segregated, suggesting that stellar clusters may have some amount of primordial mass segregationmore » already imprinted in them at an early stage. We also demonstrate that the dense core clusters have a tendency to be elongated, perhaps indicating a formation mechanism linked to the filamentary structure within molecular clouds.« less

  15. Insulator-to-conducting transition in dense fluid helium.

    PubMed

    Celliers, P M; Loubeyre, P; Eggert, J H; Brygoo, S; McWilliams, R S; Hicks, D G; Boehly, T R; Jeanloz, R; Collins, G W

    2010-05-07

    By combining diamond-anvil-cell and laser-driven shock wave techniques, we produced dense He samples up to 1.5 g/cm(3) at temperatures reaching 60 kK. Optical measurements of reflectivity and temperature show that electronic conduction in He at these conditions is temperature-activated (semiconducting). A fit to the data suggests that the mobility gap closes with increasing density, and that hot dense He becomes metallic above approximately 1.9 g/cm(3). These data provide a benchmark to test models that describe He ionization at conditions found in astrophysical objects, such as cold white dwarf atmospheres.

  16. Electrodeposition of Dense Chromium Coatings from Molten Salt Electrolytes

    DTIC Science & Technology

    1991-04-01

    AD-A235 978 . JUN 03 391 ELECTRODEPOSITION OF DENSE CHROMIUM COATINGS FROM MOLTEN SALT ELECTROLYTES Final Technical Report J t ]Vgca or by ~ 4 OTC... molten salts , pulsed currents, electrodeposition. 2. The results, on the electrodeposition of dense chromium coatings from molten salt electrolytes... salts dissolved in molten salts using the cell Cl2/C/!Cr 2 + in LiCI-KCI//Cr metal The chromium ions are introduced by anodizing a piece of chromium and

  17. Measurement of electron-ion relaxation in warm dense copper

    DOE PAGES

    Cho, B. I.; Ogitsu, T.; Engelhorn, K.; ...

    2016-01-06

    Experimental investigation of electron-ion coupling and electron heat capacity of copper in warm and dense states are presented. From time-resolved x-ray absorption spectroscopy, the temporal evolution of electron temperature is obtained for non-equilibrium warm dense copper heated by an intense femtosecond laser pulse. Electron heat capacity and electron-ion coupling are inferred from the initial electron temperature and its decrease over 10 ps. As a result, data are compared with various theoretical models.

  18. A description of the pseudorapidity distributions in heavy ion collisions at RHIC and LHC energies

    NASA Astrophysics Data System (ADS)

    Jiang, Z. J.; Zhang, Y.; Zhang, H. L.; Deng, H. P.

    2015-09-01

    The charged particles produced in nucleus-nucleus collisions are classified into two parts: One is from the hot and dense matter created in collisions. The other is from leading particles. The hot and dense matter is assumed to expand and generate particles according to BJP hydrodynamics, a theory put forward by A. Bialas, R.A. Janik and R. Peschanski. The leading particles are argued to possess a Gaussian rapidity distribution with the normalization constant equaling the number of participants. A comparison is made between the theoretical results and the experimental measurements performed by BRAHMS and PHOBOS Collaborations at BNL-RHIC in Au-Au and Cu-Cu collisions at √{sNN} = 200 GeV and by ALICE Collaboration at CERN-LHC in Pb-Pb collisions at √{sNN} = 2.76 TeV. The theoretical results are well consistent with experimental data.

  19. Prevalence of Mammographically Dense Breasts in the United States

    PubMed Central

    Gangnon, Ronald E.; Burt, Veronica; Trentham-Dietz, Amy; Hampton, John M.; Wellman, Robert D.; Kerlikowske, Karla; Miglioretti, Diana L.

    2014-01-01

    Background National legislation is under consideration that would require women with mammographically dense breasts to be informed of their breast density and encouraged to discuss supplemental breast cancer screening with their health care providers. The number of US women potentially affected by this legislation is unknown. Methods We determined the mammographic breast density distribution by age and body mass index (BMI) using data from 1518 599 mammograms conducted from 2007 through 2010 at mammography facilities in the Breast Cancer Surveillance Consortium (BCSC). We applied these breast density distributions to age- and BMI-specific counts of the US female population derived from the 2010 US Census and the National Health and Nutrition Examination Survey (NHANES) to estimate the number of US women with dense breasts. Results Overall, 43.3% (95% confidence interval [CI] = 43.1% to 43.4%) of women 40 to 74 years of age had heterogeneously or extremely dense breasts, and this proportion was inversely associated with age and BMI. Based on the age and BMI distribution of US women, we estimated that 27.6 million women (95% CI = 27.5 to 27.7 million) aged 40 to 74 years in the United States have heterogeneously or extremely dense breasts. Women aged 40 to 49 years (N = 12.3 million) accounted for 44.3% of this group. Conclusion The prevalence of dense breasts among US women of common breast cancer screening ages exceeds 25 million. Policymakers and healthcare providers should consider this large prevalence when debating breast density notification legislation and designing strategies to ensure that women who are notified have opportunities to evaluate breast cancer risk and discuss and pursue supplemental screening options if deemed appropriate. PMID:25217577

  20. Matter under extreme conditions experiments at the Linac Coherent Light Source

    DOE PAGES

    Glenzer, S. H.; Fletcher, L. B.; Galtier, E.; ...

    2015-12-10

    The Matter in Extreme Conditions end station at the Linac Coherent Light Source (LCLS) is a new tool enabling accurate pump-probe measurements for studying the physical properties of matter in the high-energy density physics regime. This instrument combines the world’s brightest x-ray source, the LCLS x-ray beam, with high-power lasers consisting of two nanosecond Nd:glass laser beams and one short-pulse Ti:sapphire laser. These lasers produce short-lived states of matter with high pressures, high temperatures or high densities with properties that are important for applications in nuclear fusion research, laboratory astrophysics and the development of intense radiation sources. In the firstmore » experiments, we have performed highly accurate x-ray diffraction and x-ray Thomson scattering techniques on shock-compressed matter resolving the transition from compressed solid matter to a co-existence regime and into the warm dense matter state. Furthermore, these complex charged-particle systems are dominated by strong correlations and quantum effects. They exist in planetary interiors and laboratory experiments, e.g., during high-power laser interactions with solids or the compression phase of inertial confinement fusion implosions. Applying record peak brightness X rays resolves the ionic interactions at atomic (Ångstrom) scale lengths and measure the static structure factor, which is a key quantity for determining equation of state data and important transport coefficients. Simultaneously, spectrally resolved measurements of plasmon features provide dynamic structure factor information that yield temperature and density with unprecedented precision at micron-scale resolution in dynamic compression experiments. This set of studies demonstrates our ability to measure fundamental thermodynamic properties that determine the state of matter in the high-energy density physics regime.« less

  1. Validation of in vivo 2D displacements from spiral cine DENSE at 3T.

    PubMed

    Wehner, Gregory J; Suever, Jonathan D; Haggerty, Christopher M; Jing, Linyuan; Powell, David K; Hamlet, Sean M; Grabau, Jonathan D; Mojsejenko, Walter Dimitri; Zhong, Xiaodong; Epstein, Frederick H; Fornwalt, Brandon K

    2015-01-30

    Displacement Encoding with Stimulated Echoes (DENSE) encodes displacement into the phase of the magnetic resonance signal. Due to the stimulated echo, the signal is inherently low and fades through the cardiac cycle. To compensate, a spiral acquisition has been used at 1.5T. This spiral sequence has not been validated at 3T, where the increased signal would be valuable, but field inhomogeneities may result in measurement errors. We hypothesized that spiral cine DENSE is valid at 3T and tested this hypothesis by measuring displacement errors at both 1.5T and 3T in vivo. Two-dimensional spiral cine DENSE and tagged imaging of the left ventricle were performed on ten healthy subjects at 3T and six healthy subjects at 1.5T. Intersection points were identified on tagged images near end-systole. Displacements from the DENSE images were used to project those points back to their origins. The deviation from a perfect grid was used as a measure of accuracy and quantified as root-mean-squared error. This measure was compared between 3T and 1.5T with the Wilcoxon rank sum test. Inter-observer variability of strains and torsion quantified by DENSE and agreement between DENSE and harmonic phase (HARP) were assessed by Bland-Altman analyses. The signal to noise ratio (SNR) at each cardiac phase was compared between 3T and 1.5T with the Wilcoxon rank sum test. The displacement accuracy of spiral cine DENSE was not different between 3T and 1.5T (1.2 ± 0.3 mm and 1.2 ± 0.4 mm, respectively). Both values were lower than the DENSE pixel spacing of 2.8 mm. There were no substantial differences in inter-observer variability of DENSE or agreement of DENSE and HARP between 3T and 1.5T. Relative to 1.5T, the SNR at 3T was greater by a factor of 1.4 ± 0.3. The spiral cine DENSE acquisition that has been used at 1.5T to measure cardiac displacements can be applied at 3T with equivalent accuracy. The inter-observer variability and agreement of DENSE-derived peak strains and

  2. Nonempirical Semilocal Free-Energy Density Functional for Matter under Extreme Conditions.

    PubMed

    Karasiev, Valentin V; Dufty, James W; Trickey, S B

    2018-02-16

    Realizing the potential for predictive density functional calculations of matter under extreme conditions depends crucially upon having an exchange-correlation (XC) free-energy functional accurate over a wide range of state conditions. Unlike the ground-state case, no such functional exists. We remedy that with systematic construction of a generalized gradient approximation XC free-energy functional based on rigorous constraints, including the free-energy gradient expansion. The new functional provides the correct temperature dependence in the slowly varying regime and the correct zero-T, high-T, and homogeneous electron gas limits. Its accuracy in the warm dense matter regime is attested by excellent agreement of the calculated deuterium equation of state with reference path integral Monte Carlo results at intermediate and elevated T. Pressure shifts for hot electrons in compressed static fcc Al and for low-density Al demonstrate the combined magnitude of thermal and gradient effects handled well by this functional over a wide T range.

  3. Nonempirical Semilocal Free-Energy Density Functional for Matter under Extreme Conditions

    NASA Astrophysics Data System (ADS)

    Karasiev, Valentin V.; Dufty, James W.; Trickey, S. B.

    2018-02-01

    Realizing the potential for predictive density functional calculations of matter under extreme conditions depends crucially upon having an exchange-correlation (X C ) free-energy functional accurate over a wide range of state conditions. Unlike the ground-state case, no such functional exists. We remedy that with systematic construction of a generalized gradient approximation X C free-energy functional based on rigorous constraints, including the free-energy gradient expansion. The new functional provides the correct temperature dependence in the slowly varying regime and the correct zero-T , high-T , and homogeneous electron gas limits. Its accuracy in the warm dense matter regime is attested by excellent agreement of the calculated deuterium equation of state with reference path integral Monte Carlo results at intermediate and elevated T . Pressure shifts for hot electrons in compressed static fcc Al and for low-density Al demonstrate the combined magnitude of thermal and gradient effects handled well by this functional over a wide T range.

  4. Guidelines for psychological evaluations in child protection matters.

    PubMed

    2013-01-01

    The problems of abused and neglected children are epidemic in our society (U.S. Department of Health and Human Services, Administration on Children, Youth, and Families, 2008) and create issues that psychologists may be called upon to address. Psychologists are positioned to contribute significantly to decision making in child protection matters. Psychological data and expertise may provide sources of information and a perspective not otherwise available to courts regarding the functioning of parties, and thus may increase the fairness of decisions by the court, state agency, or other party. such matters. These guidelines are a revision of the 1999 "Guidelines for Psychological Evaluations in Child Protection Matters" (American Psychological Association [APA], 1999). These guidelines are informed by APA's "Ethical Principles of Psychologists and Code of Conduct" ("APA Ethics Code"; APA, 2002a, 2010).

  5. Turbulence Modulation and Dense-Spray Structure

    DTIC Science & Technology

    1988-08-01

    system ............................................. 10 6 Particle size distribution (dp = 0.5 mm) .................................... 13 7 Particle size...54 27 Sketch of the pressurized test apparatus .................................... 55 28 Sketch of the double-pulse holocamera system ...58 29 Sketch of the hologram reconstruction system ............................ 59 30 Typical hologram reconstruction in the dense

  6. Sulfur chemistry in dense interstellar clouds

    NASA Technical Reports Server (NTRS)

    Prasad, S. S.; Huntress, W. T., Jr.

    1982-01-01

    A model is presented for the gas phase chemistry of molecules containing sulfur in dense interstellar clouds. The sulfur chemistry is different from that used in previous models as a result of an extensive search of the recent literature and the availability of new laboratory data. The changes have a significant effect on the calculated abundance of sulfur compounds. The linked chemistry of sulfur and oxygen in the present model requires a severe depletion of sulfur and low fractional abundances of both O and O2 in the dense clouds. In contrast, the high abundance of SO and the low abundance of CS relative to SO in the HVS in the KL may indicate an oxygen-rich, high temperature environment compared to OMC-1. The formation of S-H bonds is slow because of the absence of radiative association between S(+) and H2. The present model underestimates the abundance of H2S unless a radiative association reaction between HS(+) and H2 is postulated.

  7. Large-eddy simulation of dense gas dispersion over a simplified urban area

    NASA Astrophysics Data System (ADS)

    Wingstedt, E. M. M.; Osnes, A. N.; Åkervik, E.; Eriksson, D.; Reif, B. A. Pettersson

    2017-03-01

    Dispersion of neutral and dense gas over a simplified urban area, comprising four cubes, has been investigated by the means of large-eddy simulations (LES). The results have been compared to wind tunnel experiments and both mean and fluctuating quantities of velocity and concentration are in very good agreement. High-quality inflow profiles are necessary to achieve physically realistic LES results. In this study, profiles matching the atmospheric boundary layer flow in the wind tunnel, are generated by means of a separate precursor simulation. Emission of dense gas dramatically alters the flow in the near source region and introduces an upstream dispersion. The resulting dispersion patterns of neutral and dense gas differ significantly, where the plume in the latter case is wider and shallower. The dense gas is highly affected by the cube array, which seems to act as a barrier, effectively deflecting the plume. This leads to higher concentrations outside of the array than inside. On the contrary, the neutral gas plume has a Gaussian-type shape, with highest concentrations along the centreline. It is found that the dense gas reduces the vertical and spanwise turbulent momentum transport and, as a consequence, the turbulence kinetic energy. The reduction coincides with the area where the gradient Richardson number exceeds its critical value, i.e. where the flow may be characterized as stably stratified. Interestingly, this region does not correspond to where the concentration of dense gas is the highest (close to the ground), as this is also where the largest velocity gradients are to be found. Instead there is a layer in the middle of the dense gas cloud where buoyancy is dynamically dominant.

  8. Cosmological structure formation in Decaying Dark Matter models

    NASA Astrophysics Data System (ADS)

    Cheng, Dalong; Chu, M.-C.; Tang, Jiayu

    2015-07-01

    The standard cold dark matter (CDM) model predicts too many and too dense small structures. We consider an alternative model that the dark matter undergoes two-body decays with cosmological lifetime τ into only one type of massive daughters with non-relativistic recoil velocity Vk. This decaying dark matter model (DDM) can suppress the structure formation below its free-streaming scale at time scale comparable to τ. Comparing with warm dark matter (WDM), DDM can better reduce the small structures while being consistent with high redshfit observations. We study the cosmological structure formation in DDM by performing self-consistent N-body simulations and point out that cosmological simulations are necessary to understand the DDM structures especially on non-linear scales. We propose empirical fitting functions for the DDM suppression of the mass function and the concentration-mass relation, which depend on the decay parameters lifetime τ, recoil velocity Vk and redshift. The fitting functions lead to accurate reconstruction of the the non-linear power transfer function of DDM to CDM in the framework of halo model. Using these results, we set constraints on the DDM parameter space by demanding that DDM does not induce larger suppression than the Lyman-α constrained WDM models. We further generalize and constrain the DDM models to initial conditions with non-trivial mother fractions and show that the halo model predictions are still valid after considering a global decayed fraction. Finally, we point out that the DDM is unlikely to resolve the disagreement on cluster numbers between the Planck primary CMB prediction and the Sunyaev-Zeldovich (SZ) effect number count for τ ~ H0-1.

  9. PROCEEDINGS OF RIKEN/BNL RESEARCH CENTER WORKSHOP, EQUILIBRIUM AND NON-EQUILIBRIM ASPECTTS OF HOT, DENSE QCD, VOLUME 28.

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    DE VEGA,H.J.; BOYANOVSKY,D.

    The Relativistic Heavy Ion Collider (RHIC) at Brookhaven, beginning operation this year, and the Large Hadron Collider (LHC) at CERN, beginning operation {approximately}2005, will provide an unprecedented range of energies and luminosities that will allow us to probe the Gluon-Quark plasma. At RHIC and LHC, at central rapidity typical estimates of energy densities and temperatures are e * 1-10 GeV/fm3 and T0 * 300 - 900 MeV. Such energies are well above current estimates for the GQ plasma. Initially, this hot, dense plasma is far from local thermal equilibrium, making the theoretical study of transport phenomena, kinetic and chemical equilibrationmore » in dense and hot plasmas, and related issues a matter of fundamental importance. During the last few years a consistent framework to study collective effects in the Gluon-Quark plasma, and a microscopic description of transport in terms of the hard thermal (and dense) loops resummation program has emerged. This approach has the potential of providing a microscopic formulation of transport, in the regime of temperatures and densities to be achieved at RHIC and LHC. A parallel development over the last few years has provided a consistent formulation of non-equilibrium quantum field theory that provides a real-time description of phenomena out of equilibrium. Novel techniques including non-perturbative approaches and the dynamical renormalization group techniques lead to new insights into transport and relaxation. A deeper understanding of collective.excitations and transport phenomena in the GQ plasma could lead to recognize novel potential experimental signatures. New insights into small-c physics reveals a striking similarity between small-c and hard thermal loops, and novel real-time numerical simulations have recently studied the parton distributions and their thermalizations in the initial stages of a heavy ion collision.« less

  10. PROCEEDINGS OF RIKEN/BNL RESEARCH CENTER WORKSHOP, EQUILIBRIUM AND NON-EQUILIBRIM ASPECTS OF HOT, DENSE QCD, VOLUME 28.

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    De Vega, H.J.; Boyanovsky, D.

    The Relativistic Heavy Ion Collider (RHIC) at Brookhaven, beginning operation this year, and the Large Hadron Collider (LHC) at CERN, beginning operation {approximately}2005, will provide an unprecedented range of energies and luminosities that will allow us to probe the Gluon-Quark plasma. At RHIC and LHC, at central rapidity typical estimates of energy densities and temperatures are e * 1-10 GeV/fm3 and T0 * 300 - 900 MeV. Such energies are well above current estimates for the GQ plasma. Initially, this hot, dense plasma is far from local thermal equilibrium, making the theoretical study of transport phenomena, kinetic and chemical equilibrationmore » in dense and hot plasmas, and related issues a matter of fundamental importance. During the last few years a consistent framework to study collective effects in the Gluon-Quark plasma, and a microscopic description of transport in terms of the hard thermal (and dense) loops resummation program has emerged. This approach has the potential of providing a microscopic formulation of transport, in the regime of temperatures and densities to be achieved at RHIC and LHC. A parallel development over the last few years has provided a consistent formulation of non-equilibrium quantum field theory that provides a real-time description of phenomena out of equilibrium. Novel techniques including non-perturbative approaches and the dynamical renormalization group techniques lead to new insights into transport and relaxation. A deeper understanding of collective.excitations and transport phenomena in the GQ plasma could lead to recognize novel potential experimental signatures. New insights into small-c physics reveals a striking similarity between small-c and hard thermal loops, and novel real-time numerical simulations have recently studied the parton distributions and their thermalizations in the initial stages of a heavy ion collision.« less

  11. Local Crystalline Structure in an Amorphous Protein Dense Phase

    PubMed Central

    Greene, Daniel G.; Modla, Shannon; Wagner, Norman J.; Sandler, Stanley I.; Lenhoff, Abraham M.

    2015-01-01

    Proteins exhibit a variety of dense phases ranging from gels, aggregates, and precipitates to crystalline phases and dense liquids. Although the structure of the crystalline phase is known in atomistic detail, little attention has been paid to noncrystalline protein dense phases, and in many cases the structures of these phases are assumed to be fully amorphous. In this work, we used small-angle neutron scattering, electron microscopy, and electron tomography to measure the structure of ovalbumin precipitate particles salted out with ammonium sulfate. We found that the ovalbumin phase-separates into core-shell particles with a core radius of ∼2 μm and shell thickness of ∼0.5 μm. Within this shell region, nanostructures comprised of crystallites of ovalbumin self-assemble into a well-defined bicontinuous network with branches ∼12 nm thick. These results demonstrate that the protein gel is comprised in part of nanocrystalline protein. PMID:26488663

  12. Jammed Clusters and Non-locality in Dense Granular Flows

    NASA Astrophysics Data System (ADS)

    Kharel, Prashidha; Rognon, Pierre

    We investigate the micro-mechanisms underpinning dense granular flow behaviour from a series of DEM simulations of pure shear flows of dry grains. We observe the development of transient clusters of jammed particles within the flow. Typical size of such clusters is found to scale with the inertial number with a power law that is similar to the scaling of shear-rate profile relaxation lengths observed previously. Based on the simple argument that transient clusters of size l exist in the dense flow regime, the formulation of steady state condition for non-homogeneous shear flow results in a general non-local relation, which is similar in form to the non-local relation conjectured for soft glassy flows. These findings suggest the formation of jammed clusters to be the key micro-mechanism underpinning non-local behaviour in dense granular flows. Particles and Grains Laboratory, School of Civil Engineering, The University of Sydney, Sydney, NSW 2006, Australia.

  13. Simulations of the interaction of intense petawatt laser pulses with dense Z-pinch plasmas : final report LDRD 39670.

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Welch, Dale Robert; MacFarlane, Joseph John; Mehlhorn, Thomas Alan

    We have studied the feasibility of using the 3D fully electromagnetic implicit hybrid particle code LSP (Large Scale Plasma) to study laser plasma interactions with dense, compressed plasmas like those created with Z, and which might be created with the planned ZR. We have determined that with the proper additional physics and numerical algorithms developed during the LDRD period, LSP was transformed into a unique platform for studying such interactions. Its uniqueness stems from its ability to consider realistic compressed densities and low initial target temperatures (if required), an ability that conventional PIC codes do not possess. Through several testmore » cases, validations, and applications to next generation machines described in this report, we have established the suitability of the code to look at fast ignition issues for ZR, as well as other high-density laser plasma interaction problems relevant to the HEDP program at Sandia (e.g. backlighting).« less

  14. Experimental study of droplet formation of dense suspensions

    NASA Astrophysics Data System (ADS)

    Martensson, Gustaf; Carson, Fabian

    2017-11-01

    As with the jet printing of dyes and other low-viscosity fluids, the jetting of dense fluid suspensions is dependent on the repeatable break-off of the fluid filament into well-formed droplets. It is well known that the break-off of dense suspensions is dependent on the volume fraction of the solid phase, particle size and morphology, fluid phase viscosity et cetera, see for example van Deen et al. (2013). The purpose of this study is to establish a deeper understanding of the formation process of droplets of dense suspensions. Previous experiments have utilised a filament break-off device (FilBO) developed in-house. These experiments utilise an ejection device based on rapid volumetric displacement of the fluid through a conical nozzle. The suspension samples consist of a resin-based flux and spherical particles with diameters of dp = 5 - 25 μ m. A droplet of of the suspension with a volume of Vdrop = 2 - 50 nl is ejected from the nozzle. Correlations between droplet speed and the temporal development of the volumetric displacement will be presented. Further results relating break-off length and rate versus particle diameter, volume fraction and probe speed will be presented.

  15. Radiative-Transfer Modeling of Spectra of Densely Packed Particulate Media

    NASA Astrophysics Data System (ADS)

    Ito, G.; Mishchenko, M. I.; Glotch, T. D.

    2017-12-01

    Remote sensing measurements over a wide range of wavelengths from both ground- and space-based platforms have provided a wealth of data regarding the surfaces and atmospheres of various solar system bodies. With proper interpretations, important properties, such as composition and particle size, can be inferred. However, proper interpretation of such datasets can often be difficult, especially for densely packed particulate media with particle sizes on the order of wavelength of light being used for remote sensing. Radiative transfer theory has often been applied to the study of densely packed particulate media like planetary regoliths and snow, but with difficulty, and here we continue to investigate radiative transfer modeling of spectra of densely packed media. We use the superposition T-matrix method to compute scattering properties of clusters of particles and capture the near-field effects important for dense packing. Then, the scattering parameters from the T-matrix computations are modified with the static structure factor correction, accounting for the dense packing of the clusters themselves. Using these corrected scattering parameters, reflectance (or emissivity via Kirchhoff's Law) is computed with the method of invariance imbedding solution to the radiative transfer equation. For this work we modeled the emissivity spectrum of the 3.3 µm particle size fraction of enstatite, representing some common mineralogical and particle size components of regoliths, in the mid-infrared wavelengths (5 - 50 µm). The modeled spectrum from the T-matrix method with static structure factor correction using moderate packing densities (filling factors of 0.1 - 0.2) produced better fits to the laboratory measurement of corresponding spectrum than the spectrum modeled by the equivalent method without static structure factor correction. Future work will test the method of the superposition T-matrix and static structure factor correction combination for larger particles

  16. Dense high temperature ceramic oxide superconductors

    DOEpatents

    Landingham, Richard L.

    1993-01-01

    Dense superconducting ceramic oxide articles of manufacture and methods for producing these articles are described. Generally these articles are produced by first processing these superconducting oxides by ceramic processing techniques to optimize materials properties, followed by reestablishing the superconducting state in a desired portion of the ceramic oxide composite.

  17. Dense high temperature ceramic oxide superconductors

    DOEpatents

    Landingham, R.L.

    1993-10-12

    Dense superconducting ceramic oxide articles of manufacture and methods for producing these articles are described. Generally these articles are produced by first processing these superconducting oxides by ceramic processing techniques to optimize materials properties, followed by reestablishing the superconducting state in a desired portion of the ceramic oxide composite.

  18. Collisional excitation of molecules in dense interstellar clouds

    NASA Technical Reports Server (NTRS)

    Green, S.

    1985-01-01

    State transitions which permit the identification of the molecular species in dense interstellar clouds are reviewed, along with the techniques used to calculate the transition energies, the database on known molecular transitions and the accuracy of the values. The transition energies cannot be measured directly and therefore must be modeled analytically. Scattering theory is used to determine the intermolecular forces on the basis of quantum mechanics. The nuclear motions can also be modeled with classical mechanics. Sample rate constants are provided for molecular systems known to inhabit dense interstellar clouds. The values serve as a database for interpreting microwave and RF astrophysical data on the transitions undergone by interstellar molecules.

  19. The Compressed Baryonic Matter experiment at FAIR

    NASA Astrophysics Data System (ADS)

    Höhne, Claudia

    2018-02-01

    The CBM experiment will investigate highly compressed baryonic matter created in A+A collisions at the new FAIR research center. With a beam energy range up to 11 AGeV for the heaviest nuclei at the SIS 100 accelerator, CBM will investigate the QCD phase diagram in the intermediate range, i.e. at moderate temperatures but high net-baryon densities. This intermediate range of the QCD phase diagram is of particular interest, because a first order phase transition ending in a critical point and possibly new highdensity phases of strongly interacting matter are expected. In this range of the QCD phase diagram only exploratory measurements have been performed so far. CBM, as a next generation, high-luminosity experiment, will substantially improve our knowledge of matter created in this region of the QCD phase diagram and characterize its properties by measuring rare probes such as multi-strange hyperons, dileptons or charm, but also with event-by-event fluctuations of conserved quantities, and collective flow of identified particles. The experimental preparations with special focus on hadronic observables and strangeness is presented in terms of detector development, feasibility studies and fast track reconstruction. Preparations are progressing well such that CBM will be ready with FAIR start. As quite some detectors are ready before, they will be used as upgrades or extensions of already running experiments allowing for a rich physics program prior to FAIR start.

  20. Explosive desorption of icy grain mantles in dense clouds

    NASA Technical Reports Server (NTRS)

    Schutte, W. A.; Greenberg, J. M.

    1991-01-01

    The cycling of the condensible material in dense clouds between the gas phase and the icy grain mantles is investigated. In the model studied, desorption of the ice occurs due to grain mantle explosions when photochemically stored energy is released after transient heating by a cosmic ray particle. It is shown that, depending on the grain size distribution in dense clouds, explosive desorption can maintain up to about eight percent of the carbon in the form of CO in the gas phase at typical cloud densities.

  1. Weak synchronization and large-scale collective oscillation in dense bacterial suspensions

    NASA Astrophysics Data System (ADS)

    Chen, Chong; Liu, Song; Shi, Xia-Qing; Chaté, Hugues; Wu, Yilin

    2017-01-01

    Collective oscillatory behaviour is ubiquitous in nature, having a vital role in many biological processes from embryogenesis and organ development to pace-making in neuron networks. Elucidating the mechanisms that give rise to synchronization is essential to the understanding of biological self-organization. Collective oscillations in biological multicellular systems often arise from long-range coupling mediated by diffusive chemicals, by electrochemical mechanisms, or by biomechanical interaction between cells and their physical environment. In these examples, the phase of some oscillatory intracellular degree of freedom is synchronized. Here, in contrast, we report the discovery of a weak synchronization mechanism that does not require long-range coupling or inherent oscillation of individual cells. We find that millions of motile cells in dense bacterial suspensions can self-organize into highly robust collective oscillatory motion, while individual cells move in an erratic manner, without obvious periodic motion but with frequent, abrupt and random directional changes. So erratic are individual trajectories that uncovering the collective oscillations of our micrometre-sized cells requires individual velocities to be averaged over tens or hundreds of micrometres. On such large scales, the oscillations appear to be in phase and the mean position of cells typically describes a regular elliptic trajectory. We found that the phase of the oscillations is organized into a centimetre-scale travelling wave. We present a model of noisy self-propelled particles with strictly local interactions that accounts faithfully for our observations, suggesting that self-organized collective oscillatory motion results from spontaneous chiral and rotational symmetry breaking. These findings reveal a previously unseen type of long-range order in active matter systems (those in which energy is spent locally to produce non-random motion). This mechanism of collective oscillation may

  2. Weak synchronization and large-scale collective oscillation in dense bacterial suspensions.

    PubMed

    Chen, Chong; Liu, Song; Shi, Xia-Qing; Chaté, Hugues; Wu, Yilin

    2017-02-09

    Collective oscillatory behaviour is ubiquitous in nature, having a vital role in many biological processes from embryogenesis and organ development to pace-making in neuron networks. Elucidating the mechanisms that give rise to synchronization is essential to the understanding of biological self-organization. Collective oscillations in biological multicellular systems often arise from long-range coupling mediated by diffusive chemicals, by electrochemical mechanisms, or by biomechanical interaction between cells and their physical environment. In these examples, the phase of some oscillatory intracellular degree of freedom is synchronized. Here, in contrast, we report the discovery of a weak synchronization mechanism that does not require long-range coupling or inherent oscillation of individual cells. We find that millions of motile cells in dense bacterial suspensions can self-organize into highly robust collective oscillatory motion, while individual cells move in an erratic manner, without obvious periodic motion but with frequent, abrupt and random directional changes. So erratic are individual trajectories that uncovering the collective oscillations of our micrometre-sized cells requires individual velocities to be averaged over tens or hundreds of micrometres. On such large scales, the oscillations appear to be in phase and the mean position of cells typically describes a regular elliptic trajectory. We found that the phase of the oscillations is organized into a centimetre-scale travelling wave. We present a model of noisy self-propelled particles with strictly local interactions that accounts faithfully for our observations, suggesting that self-organized collective oscillatory motion results from spontaneous chiral and rotational symmetry breaking. These findings reveal a previously unseen type of long-range order in active matter systems (those in which energy is spent locally to produce non-random motion). This mechanism of collective oscillation may

  3. Ultra-bright γ-ray emission and dense positron production from two laser-driven colliding foils.

    PubMed

    Li, Han-Zhen; Yu, Tong-Pu; Liu, Jin-Jin; Yin, Yan; Zhu, Xing-Long; Capdessus, Remi; Pegoraro, Francesco; Sheng, Zheng-Ming; McKenna, Paul; Shao, Fu-Qiu

    2017-12-11

    Matter can be transferred into energy and the opposite transformation is also possible by use of high-power lasers. A laser pulse in plasma can convert its energy into γ-rays and then e - e + pairs via the multi-photon Breit-Wheeler process. Production of dense positrons at GeV energies is very challenging since extremely high laser intensity ~10 24  Wcm -2 is required. Here we propose an all-optical scheme for ultra-bright γ-ray emission and dense positron production with lasers at intensity of 10 22-23  Wcm -2 . By irradiating two colliding elliptically-polarized lasers onto two diamondlike carbon foils, electrons in the focal region of one foil are rapidly accelerated by the laser radiation pressure and interact with the other intense laser pulse which penetrates through the second foil due to relativistically induced foil transparency. This symmetric configuration enables efficient Compton back-scattering and results in ultra-bright γ-photon emission with brightness of ~10 25 photons/s/mm 2 /mrad 2 /0.1%BW at 15 MeV and intensity of 5 × 10 23  Wcm -2 . Our first three-dimensional simulation with quantum-electrodynamics incorporated shows that a GeV positron beam with density of 2.5 × 10 22 cm -3 and flux of 1.6 × 10 10 /shot is achieved. Collective effects of the pair plasma may be also triggered, offering a window on investigating laboratory astrophysics at PW laser facilities.

  4. Thermodynamics of cosmological matter creation

    PubMed Central

    Prigogine, I.; Geheniau, J.; Gunzig, E.; Nardone, P.

    1988-01-01

    A type of cosmological history that includes large-scale entropy production is proposed. These cosmologies are based on reinterpretation of the matter-energy stress tensor in Einstein's equations. This modifies the usual adiabatic energy conservation laws, thereby including irreversible matter creation. This creation corresponds to an irreversible energy flow from the gravitational field to the created matter constituents. This point of view results from consideration of the thermodynamics of open systems in the framework of cosmology. It is shown that the second law of thermodynamics requires that space-time transforms into matter, while the inverse transformation is forbidden. It appears that the usual initial singularity associated with the big bang is structurally unstable with respect to irreversible matter creation. The corresponding cosmological history therefore starts from an instability of the vacuum rather than from a singularity. This is exemplified in the framework of a simple phenomenological model that leads to a three-stage cosmology: the first drives the cosmological system from the initial instability to a de Sitter regime, and the last connects with the usual matter-radiation Robertson-Walker universe. Matter as well as entropy creation occurs during the first two stages, while the third involves the traditional cosmological evolution. A remarkable fact is that the de Sitter stage appears to be an attractor independent of the initial fluctuation. This is also the case for all the physical predictions involving the present Robertson-Walker universe. Most results obtained previously, in the framework of quantum field theory, can now be obtained on a macroscopic basis. It is shown that this description leads quite naturally to the introduction of primeval black holes as the intermediate stage between the Minkowski vacuum and the present matter-radiation universe. The instability at the origin of the universe is the result of fluctuations of the

  5. Multicontextual correlates of energy-dense, nutrient-poor snack food consumption by adolescents

    PubMed Central

    Larson, Nicole; Miller, Jonathan M.; Eisenberg, Marla E.; Watts, Allison W.; Story, Mary; Neumark-Sztainer, Dianne

    2017-01-01

    Frequent consumption of energy-dense, nutrient-poor snack foods is an eating behavior of public health concern. This study was designed to inform strategies for reducing adolescent intake of energy-dense snack foods by identifying individual and environmental influences. Surveys were completed in 2009-2010 by 2,540 adolescents (54% females, mean age=14.5±2.0, 80% nonwhite) in Minneapolis-St. Paul, Minnesota schools. Daily servings of energy-dense snack food was assessed using a food frequency questionnaire that asked about consumption of 21 common snack food items, such as potato chips, cookies, and candy. Data representing characteristics of adolescents’ environments were collected from parents/caregivers, friends, school personnel, Geographic Information System sources, and a content analysis of favorite television shows. Linear regression was used to examine relationships between each individual or environmental characteristic and snack food consumption in separate models and also to examine relationships in a model including all of the characteristics simultaneously. The factors found to be significantly associated with higher energy-dense snack food intake represented individual attitudes/behaviors (e.g., snacking while watching television) and characteristics of home/family (e.g., home unhealthy food availability), peer (friends’ energy-dense snack food consumption), and school (e.g., student snack consumption norms) environments. In total, 25.5% of the variance in adolescents’ energy-dense snack food consumption was explained when factors from within each context were examined together. The results suggest that the design of interventions targeting improvement in the dietary quality of adolescents’ snack food choices should address relevant individual factors (e.g., eating while watching television) along with characteristics of their home/family (e.g., limiting the availability of unhealthy foods), peer (e.g., guiding the efforts of a peer leader

  6. Airborne Laser Swath Mapping: Improved Penetration of Dense Vegetation Opens New Applications

    NASA Astrophysics Data System (ADS)

    Carter, W. E.; Shrestha, R. L.; Slatton, K. C.

    2009-12-01

    Historically, mapping structures and terrain obscured by dense forests has been problematical, because shadows limit or prevent the use of airborne photogrammetric techniques, and ground surveying techniques are slow, labor intensive, and too costly for many applications. Airborne laser swath mapping (ALSM) units with pulse rates of a few thousand to a few tens of thousands of pulses per second typically resulted in 1 or 2 points per square meter of terrain, which worked reasonably well in sparse to moderately forested areas. For example, data collected with a 30 kHz laser, provided sufficient returns from the ground in areas covered with redwood, mixed hardwoods, and conifer forests, to create 1 to 2 meter resolution bare earth digital elevation models (DEM). These DEMs were useful in studies of forest covered landslides, terraces, and fault lines. However, in dense semi-tropical areas of Florida, with primary and secondary canopies that include dense brush such as palmetto, the DEMs were significantly degraded, and in many areas it was not possible to derive bare earth DEMs that were reliable in height to better than 0.5 to 1.0 meter. In 2007 the UF purchased a second generation Optech ALSM unit that has decimeter accuracy ranging with pulse rates of 100 to 125 kHz. Flying at 600 meters AGL, 60 meters per second, and using a scan angle of ± 20 degrees and scan rate of 40 Hz, results in about 5 laser pulses per square meter within a single swath. In April 2009 a UF team collected ALSM observations covering approximately 2000 acres at Caracol, Belize, to support archaeological studies of the ancient (650 to 900AD) Mayan city, which is largely covered with dense jungle. By overlapping adjacent swaths by 50%, and flying the project area twice with orthogonal flight lines, an accumulated data set containing approximately 20 pulses per square meter, with a distribution of incident angles was realized. The Caracol area has been under study for 25 years and traditional

  7. Oxygen ion-conducting dense ceramic

    DOEpatents

    Balachandran, Uthamalingam; Kleefisch, Mark S.; Kobylinski, Thaddeus P.; Morissette, Sherry L.; Pei, Shiyou

    1998-01-01

    Preparation, structure, and properties of mixed metal oxide compositions and their uses are described. Mixed metal oxide compositions of the invention have stratified crystalline structure identifiable by means of powder X-ray diffraction patterns. In the form of dense ceramic membranes, the present compositions demonstrate an ability to separate oxygen selectively from a gaseous mixture containing oxygen and one or more other volatile components by means of ionic conductivities.

  8. Charge-Transfer Processes in Warm Dense Matter: Selective Spectral Filtering for Laser-Accelerated Ion Beams

    NASA Astrophysics Data System (ADS)

    Braenzel, J.; Barriga-Carrasco, M. D.; Morales, R.; Schnürer, M.

    2018-05-01

    We investigate, both experimentally and theoretically, how the spectral distribution of laser accelerated carbon ions can be filtered by charge exchange processes in a double foil target setup. Carbon ions at multiple charge states with an initially wide kinetic energy spectrum, from 0.1 to 18 MeV, were detected with a remarkably narrow spectral bandwidth after they had passed through an ultrathin and partially ionized foil. With our theoretical calculations, we demonstrate that this process is a consequence of the evolution of the carbon ion charge states in the second foil. We calculated the resulting spectral distribution separately for each ion species by solving the rate equations for electron loss and capture processes within a collisional radiative model. We determine how the efficiency of charge transfer processes can be manipulated by controlling the ionization degree of the transfer matter.

  9. Increasing low-energy-dense foods and decreasing high-energy-dense foods differently influence weight loss trial outcomes

    PubMed Central

    Vadiveloo, M; Parker, H; Raynor, H

    2018-01-01

    BACKGROUND/OBJECTIVE Although reducing energy density (ED) enhances weight loss, it is unclear whether all dietary strategies that reduce ED are comparable, hindering effective ED guidelines for obesity treatment. This study examined how changes in number of low-energy-dense (LED) (<4.186 kJ/1.0 kcal g−1) and high-energy-dense (HED) (>12.56 kJ/3.0 kcal g−1) foods consumed affected dietary ED and weight loss within an 18-month weight loss trial. METHODS This secondary analysis examined data from participants randomized to an energy-restricted lifestyle intervention or lifestyle intervention plus limited non-nutrient dense, energy-dense food variety (n = 183). Number of daily LED and HED foods consumed was calculated from three, 24-h dietary recalls and anthropometrics were measured at 0, 6 and 18 months. Multivariable-adjusted generalized linear models and repeated-measures mixed linear models examined associations between 6-month changes in number of LED and HED foods and changes in ED, body mass index (BMI), and percent weight loss at 6 and 18 months. RESULTS Among mostly female (58%), White (92%) participants aged 51.9 years following an energy-restricted diet, increasing number of LED foods or decreasing number of HED foods consumed was associated with 6- and 18-month reductions in ED (β = − 0.25 to − 0.38 kJ g−1 (−0.06 to − 0.09 kcal g−1), P<0.001). Only increasing number of LED foods consumed was associated with 6- and 18-month reductions in BMI (β = − 0.16 to − 0.2 kg m−2, P<0.05) and 6-month reductions in percent weight loss (β = − 0.5%, P<0.05). Participants consuming ≤2 HED foods per day and ≥6.6 LED foods per day experienced better weight loss outcomes at 6- and 18-month than participants only consuming ≤2 HED foods per day. CONCLUSION Despite similar reductions in ED from reducing number of HED foods or increasing number of LED foods consumed, only increasing number of LED foods related to weight loss. This provides

  10. Numerical modeling for dilute and dense sprays

    NASA Technical Reports Server (NTRS)

    Chen, C. P.; Kim, Y. M.; Shang, H. M.; Ziebarth, J. P.; Wang, T. S.

    1992-01-01

    We have successfully implemented a numerical model for spray-combustion calculations. In this model, the governing gas-phase equations in Eulerian coordinate are solved by a time-marching multiple pressure correction procedure based on the operator-splitting technique. The droplet-phase equations in Lagrangian coordinate are solved by a stochastic discrete particle technique. In order to simplify the calculation procedure for the circulating droplets, the effective conductivity model is utilized. The k-epsilon models are utilized to characterize the time and length scales of the gas phase in conjunction with turbulent modulation by droplets and droplet dispersion by turbulence. This method entails random sampling of instantaneous gas flow properties and the stochastic process requires a large number of computational parcels to produce the satisfactory dispersion distributions even for rather dilute sprays. Two major improvements in spray combustion modelings were made. Firstly, we have developed a probability density function approach in multidimensional space to represent a specific computational particle. Secondly, we incorporate the Taylor Analogy Breakup (TAB) model for handling the dense spray effects. This breakup model is based on the reasonable assumption that atomization and drop breakup are indistinguishable processes within a dense spray near the nozzle exit. Accordingly, atomization is prescribed by injecting drops which have a characteristic size equal to the nozzle exit diameter. Example problems include the nearly homogeneous and inhomogeneous turbulent particle dispersion, and the non-evaporating, evaporating, and burning dense sprays. Comparison with experimental data will be discussed in detail.

  11. Dense Deposit Disease and C3 Glomerulopathy

    PubMed Central

    Barbour, Thomas D.; Pickering, Matthew C.; Terence Cook, H.

    2013-01-01

    Summary C3 glomerulopathy refers to those renal lesions characterized histologically by predominant C3 accumulation within the glomerulus, and pathogenetically by aberrant regulation of the alternative pathway of complement. Dense deposit disease is distinguished from other forms of C3 glomerulopathy by its characteristic appearance on electron microscopy. The extent to which dense deposit disease also differs from other forms of C3 glomerulopathy in terms of clinical features, natural history, and outcomes of treatment including renal transplantation is less clear. We discuss the pathophysiology of C3 glomerulopathy, with evidence for alternative pathway dysregulation obtained from affected individuals and complement factor H (Cfh)-deficient animal models. Recent linkage studies in familial C3 glomerulopathy have shown genomic rearrangements in the Cfh-related genes, for which the novel pathophysiologic concept of Cfh deregulation has been proposed. PMID:24161036

  12. DENSE NONAQUEOUS PHASE LIQUIDS -- A WORKSHOP SUMMARY

    EPA Science Inventory

    site characterization, and, therefore, DNAPL remediation, can be expected. Dense nonaqueous phase liquids (DNAPLs) in the subsurface are long-term sources of ground-water contamination, and may persist for centuries before dissolving completely in adjacent ground water. In respo...

  13. Dose-dense weekly chemotherapy in advanced ovarian cancer: An updated meta-analysis of randomized controlled trials.

    PubMed

    Marchetti, C; De Felice, F; Di Pinto, A; D'Oria, O; Aleksa, N; Musella, A; Palaia, I; Muzii, L; Tombolini, V; Benedetti Panici, P

    2018-05-01

    The use of dose-dense weekly chemotherapy in the management of advanced ovarian cancer (OC) remains controversial. The aim of this meta-analysis was to evaluate the efficacy of dose-dense regimen to improve clinical outcomes in OC patients with the inclusion of new trials. For this updated meta-analysis, PubMed Medline and Scopus databases and meeting proceedings were searched for eligible studies with the limitation of randomized controlled trials, comparing dose-dense chemotherapy versus standard treatment. Trials were grouped in two types of dose-dense chemotherapy: weekly dose-dense (both paclitaxel and carboplatin weekly administration) and semi-weekly dose-dense (weekly paclitaxel and three weekly carboplatin administration). Data were extracted independently and were analyzed using RevMan statistical software version 5.3 (http://www.cochrane.org). Primary end-point was progression-free survival (PFS). Four randomized controlled trials comprising 3698 patients were identified as eligible. Dose-dense chemotherapy had not a significant benefit on PFS (HR 0.92, 95% CI 0.81-1.04, p = 0.20). When the analysis was restricted to both weekly and semi-weekly dose-dense data, a no significant interaction between dose-dense and standard regimen was confirmed (HR 1.01, 95% CI 0.93-1.10 and HR 0.82, 95% CI 0.63-1.08, respectively). In the absence of PFS superiority of dose-dense schedule, three weekly schedule should remain the standard of care for advanced OC. Copyright © 2018 Elsevier B.V. All rights reserved.

  14. A combined model for pseudo-rapidity distributions in Cu-Cu collisions at BNL-RHIC energies

    NASA Astrophysics Data System (ADS)

    Jiang, Z. J.; Wang, J.; Huang, Y.

    2016-04-01

    The charged particles produced in nucleus-nucleus collisions come from leading particles and those frozen out from the hot and dense matter created in collisions. The leading particles are conventionally supposed having Gaussian rapidity distributions normalized to the number of participants. The hot and dense matter is assumed to expand according to the unified hydrodynamics, a hydro model which unifies the features of Landau and Hwa-Bjorken model, and freeze out into charged particles from a time-like hypersurface with a proper time of τFO. The rapidity distribution of this part of charged particles can be derived analytically. The combined contribution from both leading particles and unified hydrodynamics is then compared against the experimental data performed by BNL-RHIC-PHOBOS Collaboration in different centrality Cu-Cu collisions at sNN = 200 and 62.4GeV, respectively. The model predictions are consistent with experimental measurements.

  15. Visible light emission measurements from a dense electrothermal launcher plasma

    NASA Astrophysics Data System (ADS)

    Hankins, O. E.; Bourham, M. A.; Earnhart, J.; Gilligan, J. G.

    1993-01-01

    Measurements of the visible light emission from dense, weakly non-ideal plasmas have been performed on the experimental electrothermal launcher device 'SIRENS'. The plasma is created by the ablation or a Lexan insulator in the source, which then flows through a cylindrical barrel which serves as the material sample. Visible light emission spectra have been observed both in-bore and from the muzzle flash or the barrel, and from the flash or the source. Due to high plasma opacity (the plasma emits as a near blackbody) and absorption by the molecular components of the vapor shield, the hotter core or the arc has been difficult to observe. Recent measurements along the axis or the device indicate time-averaged plasma temperatures in the barrel or about 1 eV for lower energy shots, which agree with experimental measurements of the average heat flux and plasma conductivity along the barrel. Measurements or visible emission from the source indicate time averaged temperatures of 1 to 2 eV which agree with the theoretical estimates derived from ablated mass measurements and calculated estimates derived from plasma conductivity measurements.

  16. On the dense water spreading off the Ross Sea shelf (Southern Ocean)

    NASA Astrophysics Data System (ADS)

    Budillon, G.; Gremes Cordero, S.; Salusti, E.

    2002-07-01

    In this study, current meter and hydrological data obtained during the X Italian Expedition in the Ross Sea (CLIMA Project) are analyzed. Our data show a nice agreement with previous data referring to the water masses present in this area and their dynamics. Here, they are used to further analyze the mixing and deepening processes of Deep Ice Shelf Water (DISW) over the northern shelf break of the Ross Sea. In more detail, our work is focused on the elementary mechanisms that are the most efficient in removing dense water from the shelf: either classical mixing effects or density currents that interact with some topographic irregularity in order to drop to deeper levels, or also the variability of the Antarctic Circumpolar Current (ACC) which, in its meandering, can push the dense water off the shelf, thus interrupting its geostrophic flow. We also discuss in detail the (partial) evidence of dramatic interactions of the dense water with bottom particulate, of geological or biological origin, thus generating impulsive or quasi-steady density-turbidity currents. This complex interaction allows one to consider bottom particular and dense water as a unique self-interacting system. In synthesis, this is a first tentative analysis of the effect of bottom particulate on the dense water dynamics in the Ross Sea.

  17. Early dynamics of transversally thermalized matter

    NASA Astrophysics Data System (ADS)

    Bialas, A.; Chojnacki, M.; Florkowski, W.

    2008-10-01

    We argue that the idea that the parton system created in relativistic heavy-ion collisions is formed in a state with transverse momenta close to thermodynamic equilibrium and its subsequent dynamics at early times is dominated by pure transverse hydrodynamics of the perfect fluid is compatible with the data collected at RHIC. This scenario of early parton dynamics may help to solve the problem of early equilibration. Quark Matter 2008, Jaipur, India, February 2008.

  18. Dietary intake of energy-dense, nutrient-poor and nutrient-dense food sources in children with cystic fibrosis.

    PubMed

    Sutherland, Rosie; Katz, Tamarah; Liu, Victoria; Quintano, Justine; Brunner, Rebecca; Tong, Chai Wei; Collins, Clare E; Ooi, Chee Y

    2018-04-30

    Prescription of a high-energy, high-fat diet is a mainstay of nutrition management in cystic fibrosis (CF). However, families may be relying on energy-dense, nutrient-poor (EDNP) foods rather than nutrient-dense (ND) foods to meet dietary targets. We aimed to evaluate the relative contribution of EDNP and ND foods to the usual diets of children with CF and identify sociodemographic factors associated with higher EDNP intakes. This is a cross-sectional comparison of children with CF aged 2-18 years and age- and gender-matched controls. Dietary intake was assessed using the Australian Child and Adolescent Eating Survey (ACAES) food frequency questionnaire. Children with CF (n = 80: 37 males; mean age 9.3 years) consumed significantly more EDNP foods than controls (mean age 9.8 years) in terms of both total energy (median [IQR]: 1301 kcal/day (843-1860) vs. 686 kcal/day (480-1032); p < 0.0001), and as a proportion of energy intake (median [IQR]: 44% (34-51) vs. 31% (24-43); p < 0.0001). Although children with CF met their estimated energy requirements (median [IQR]: 158% (124-187) vs. 112% (90-137); p < 0.0001) and their diets were high in fat (median [IQR]: 38% (35-41) vs. 34% (32-36); p < 0.0001), this was largely attributable to EDNP foods. High EDNP intakes (≥10 serves/day) were associated with socioeconomic disadvantage (p = 0.01) and rural residential location (p = 0.03). The energy- and fat-dense CF diet is primarily achieved by overconsumption of EDNP foods, rather than ND sources. This dietary pattern may not be optimal for the future health of children with CF, who are now expected to survive well into adulthood. Copyright © 2018 European Cystic Fibrosis Society. All rights reserved.

  19. Traversable wormholes without exotic matter in multimetric repulsive gravity

    NASA Astrophysics Data System (ADS)

    Hohmann, Manuel

    2014-04-01

    We present a static, spherically symmetric, traversable wormhole solution to multimetric gravity which is sustained by only nonexotic matter, i.e., matter which satisfies all energy conditions. The possibility of this solution arises from the fact that under certain conditions the multimetric gravitational field equations reduce to the Einstein equations, but with a negative effective gravitational constant. We show that the Arnowitt-Deser-Misner mass of this wormhole vanishes, so that it appears massless to observers in the asymptotically flat spacetime. We finally speculate on the feasibility of creating and maintaining this type of wormhole by an advanced civilization.

  20. Effect of antecedent terrestrial land-use on C and N cycling in created wetlands

    NASA Astrophysics Data System (ADS)

    McCalley, C. K.; Al Graiti, T.; Williams, T.; Huang, S.; McGowan, M. B.; Eddingsaas, N. C.; Tyler, A. C.

    2017-12-01

    Land-use legacies and their interaction with both management actions and climate variability has a poorly characterized impact on the development of ecosystem functions and the trajectory of climate-carbon feedbacks. The complex structure-function relationships in wetlands foster delivery of valuable, climate sensitive, ecosystem services (carbon sequestration, nutrient removal, flood control, etc.) but also make them susceptible to colonization by invasive plants and lead to emission of key greenhouse gases. This project uses created wetland ecosystems as a model to understand how heterogeneity in antecedent conditions interacts with management options to create unique structure-function scenarios and a range of climate feedback outcomes. We utilized ongoing experiments in created wetlands that differ in antecedent conditions (crop agriculture, livestock grazing) and investigated how management options (invasive species removal, organic matter addition) interact with legacy impacts to promote key ecosystem functions, including greenhouse gas emissions, carbon sequestration, denitrification and plant biodiversity. The effects of antecedent land-use on soil chemistry, coupled with hydrologic patterns resulted in wetlands with divergent C and N dynamics despite their similar creation history. Additionally, the occurrence of extreme weather events (drought and excessive flooding) during the study period highlighted the overarching role that increased climate variability will play in determining key ecosystem processes in wetlands. Responses to management were linked to hydro-period: while organic matter addition successfully increased soil organic matter to more closely replicate natural systems at all sites, it had the largest impact on C and N cycling when soils were saturated. Overall, environmental conditions that promoted saturated soils, both those shaped by human activities or climate extremes, enhanced primary productivity, nutrient removal and greenhouse gas

  1. Non-native seagrass Halophila stipulacea forms dense mats under eutrophic conditions in the Caribbean

    NASA Astrophysics Data System (ADS)

    van Tussenbroek, B. I.; van Katwijk, M. M.; Bouma, T. J.; van der Heide, T.; Govers, L. L.; Leuven, R. S. E. W.

    2016-09-01

    Seagrasses comprise 78 species and are rarely invasive. But the seagrass Halophila stipulacea, firstly recorded in the Caribbean in the year 2002, has spread quickly throughout the region. Previous works have described this species as invasive in the Caribbean, forming dense mats that exclude native seagrass species. During a reconnaissance field survey of Caribbean seagrass meadows at the islands of Bonaire and Sint Maarten in 2013, we observed that this species was only extremely dense at 5 out of 10 studied meadows. Compared to areas with sparse growth of H. stipulacea, these dense meadows showed consistently higher nutrient concentrations, as indicated by higher leaf tissue N contents of the seagrass Thalassia testudinum (dense when C:N < 22.5) and sediments (dense when %N > 11.3). Thus, the potential invasiveness of this non-native seagrass most likely depends on the environmental conditions, especially the nutrient concentrations.

  2. Multicontextual correlates of energy-dense, nutrient-poor snack food consumption by adolescents.

    PubMed

    Larson, Nicole; Miller, Jonathan M; Eisenberg, Marla E; Watts, Allison W; Story, Mary; Neumark-Sztainer, Dianne

    2017-05-01

    Frequent consumption of energy-dense, nutrient-poor snack foods is an eating behavior of public health concern. This study was designed to inform strategies for reducing adolescent intake of energy-dense snack foods by identifying individual and environmental influences. Surveys were completed in 2009-2010 by 2540 adolescents (54% females, mean age = 14.5 ± 2.0, 80% nonwhite) in Minneapolis-St. Paul, Minnesota schools. Daily servings of energy-dense snack food was assessed using a food frequency questionnaire that asked about consumption of 21 common snack food items, such as potato chips, cookies, and candy. Data representing characteristics of adolescents' environments were collected from parents/caregivers, friends, school personnel, Geographic Information System sources, and a content analysis of favorite television shows. Linear regression was used to examine relationships between each individual or environmental characteristic and snack food consumption in separate models and also to examine relationships in a model including all of the characteristics simultaneously. The factors found to be significantly associated with higher energy-dense snack food intake represented individual attitudes/behaviors (e.g., snacking while watching television) and characteristics of home/family (e.g., home unhealthy food availability), peer (friends' energy-dense snack food consumption), and school (e.g., student snack consumption norms) environments. In total, 25.5% of the variance in adolescents' energy-dense snack food consumption was explained when factors from within each context were examined together. The results suggest that the design of interventions targeting improvement in the dietary quality of adolescents' snack food choices should address relevant individual factors (e.g., eating while watching television) along with characteristics of their home/family (e.g., limiting the availability of unhealthy foods), peer (e.g., guiding the efforts of a peer leader in

  3. Pulsar-irradiated stars in dense globular clusters

    NASA Technical Reports Server (NTRS)

    Tavani, Marco

    1992-01-01

    We discuss the properties of stars irradiated by millisecond pulsars in 'hard' binaries of dense globular clusters. Irradiation by a relativistic pulsar wind as in the case of the eclipsing millisecond pulsar PSR 1957+20 alter both the magnitude and color of the companion star. Some of the blue stragglers (BSs) recently discovered in dense globular clusters can be irradiated stars in binaries containing powerful millisecond pulsars. The discovery of pulsar-driven orbital modulations of BS brightness and color with periods of a few hours together with evidence for radio and/or gamma-ray emission from BS binaries would valuably contribute to the understanding of the evolution of collapsed stars in globular clusters. Pulsar-driven optical modulation of cluster stars might be the only observable effect of a new class of binary pulsars, i.e., hidden millisecond pulsars enshrouded in the evaporated material lifted off from the irradiated companion star.

  4. A New Black Carbon Sensor for Dense Air Quality Monitoring Networks

    PubMed Central

    Caubel, Julien J.; Cados, Troy E.; Kirchstetter, Thomas W.

    2018-01-01

    Low-cost air pollution sensors are emerging and increasingly being deployed in densely distributed wireless networks that provide more spatial resolution than is typical in traditional monitoring of ambient air quality. However, a low-cost option to measure black carbon (BC)—a major component of particulate matter pollution associated with adverse human health risks—is missing. This paper presents a new BC sensor designed to fill this gap, the Aerosol Black Carbon Detector (ABCD), which incorporates a compact weatherproof enclosure, solar-powered rechargeable battery, and cellular communication to enable long-term, remote operation. This paper also demonstrates a data processing methodology that reduces the ABCD’s sensitivity to ambient temperature fluctuations, and therefore improves measurement performance in unconditioned operating environments (e.g., outdoors). A fleet of over 100 ABCDs was operated outdoors in collocation with a commercial BC instrument (Magee Scientific, Model AE33) housed inside a regulatory air quality monitoring station. The measurement performance of the 105 ABCDs is comparable to the AE33. The fleet-average precision and accuracy, expressed in terms of mean absolute percentage error, are 9.2 ± 0.8% (relative to the fleet average data) and 24.6 ± 0.9% (relative to the AE33 data), respectively (fleet-average ± 90% confidence interval). PMID:29494528

  5. A New Black Carbon Sensor for Dense Air Quality Monitoring Networks.

    PubMed

    Caubel, Julien J; Cados, Troy E; Kirchstetter, Thomas W

    2018-03-01

    Low-cost air pollution sensors are emerging and increasingly being deployed in densely distributed wireless networks that provide more spatial resolution than is typical in traditional monitoring of ambient air quality. However, a low-cost option to measure black carbon (BC)-a major component of particulate matter pollution associated with adverse human health risks-is missing. This paper presents a new BC sensor designed to fill this gap, the Aerosol Black Carbon Detector (ABCD), which incorporates a compact weatherproof enclosure, solar-powered rechargeable battery, and cellular communication to enable long-term, remote operation. This paper also demonstrates a data processing methodology that reduces the ABCD's sensitivity to ambient temperature fluctuations, and therefore improves measurement performance in unconditioned operating environments (e.g., outdoors). A fleet of over 100 ABCDs was operated outdoors in collocation with a commercial BC instrument (Magee Scientific, Model AE33) housed inside a regulatory air quality monitoring station. The measurement performance of the 105 ABCDs is comparable to the AE33. The fleet-average precision and accuracy, expressed in terms of mean absolute percentage error, are 9.2 ± 0.8% (relative to the fleet average data) and 24.6 ± 0.9% (relative to the AE33 data), respectively (fleet-average ± 90% confidence interval).

  6. The Angular Momentum of Baryons and Dark Matter Halos Revisited

    NASA Technical Reports Server (NTRS)

    Kimm, Taysun; Devriendt, Julien; Slyz, Adrianne; Pichon, Christophe; Kassin, Susan A.; Dubois, Yohan

    2011-01-01

    Recent theoretical studies have shown that galaxies at high redshift are fed by cold, dense gas filaments, suggesting angular momentum transport by gas differs from that by dark matter. Revisiting this issue using high-resolution cosmological hydrodynamics simulations with adaptive-mesh refinement (AMR), we find that at the time of accretion, gas and dark matter do carry a similar amount of specific angular momentum, but that it is systematically higher than that of the dark matter halo as a whole. At high redshift, freshly accreted gas rapidly streams into the central region of the halo, directly depositing this large amount of angular momentum within a sphere of radius r = 0.1R(sub vir). In contrast, dark matter particles pass through the central region unscathed, and a fraction of them ends up populating the outer regions of the halo (r/R(sub vir) > 0.1), redistributing angular momentum in the process. As a result, large-scale motions of the cosmic web have to be considered as the origin of gas angular momentum rather than its virialised dark matter halo host. This generic result holds for halos of all masses at all redshifts, as radiative cooling ensures that a significant fraction of baryons remain trapped at the centre of the halos. Despite this injection of angular momentum enriched gas, we predict an amount for stellar discs which is in fair agreement with observations at z=0. This arises because the total specific angular momentum of the baryons (gas and stars) remains close to that of dark matter halos. Indeed, our simulations indicate that any differential loss of angular momentum amplitude between the two components is minor even though dark matter halos continuously lose between half and two-thirds of their specific angular momentum modulus as they evolve. In light of our results, a substantial revision of the standard theory of disc formation seems to be required. We propose a new scenario where gas efficiently carries the angular momentum generated

  7. Identifying women with dense breasts at high risk for interval cancer: a cohort study.

    PubMed

    Kerlikowske, Karla; Zhu, Weiwei; Tosteson, Anna N A; Sprague, Brian L; Tice, Jeffrey A; Lehman, Constance D; Miglioretti, Diana L

    2015-05-19

    Twenty-one states have laws requiring that women be notified if they have dense breasts and that they be advised to discuss supplemental imaging with their provider. To better direct discussions of supplemental imaging by determining which combinations of breast cancer risk and Breast Imaging Reporting and Data System (BI-RADS) breast density categories are associated with high interval cancer rates. Prospective cohort. Breast Cancer Surveillance Consortium (BCSC) breast imaging facilities. 365,426 women aged 40 to 74 years who had 831,455 digital screening mammography examinations. BI-RADS breast density, BCSC 5-year breast cancer risk, and interval cancer rate (invasive cancer ≤12 months after a normal mammography result) per 1000 mammography examinations. High interval cancer rate was defined as more than 1 case per 1000 examinations. High interval cancer rates were observed for women with 5-year risk of 1.67% or greater and extremely dense breasts or 5-year risk of 2.50% or greater and heterogeneously dense breasts (24% of all women with dense breasts). The interval rate of advanced-stage disease was highest (>0.4 case per 1000 examinations) among women with 5-year risk of 2.50% or greater and heterogeneously or extremely dense breasts (21% of all women with dense breasts). Five-year risk was low to average (0% to 1.66%) for 51.0% of women with heterogeneously dense breasts and 52.5% with extremely dense breasts, with interval cancer rates of 0.58 to 0.63 and 0.72 to 0.89 case per 1000 examinations, respectively. The benefit of supplemental imaging was not assessed. Breast density should not be the sole criterion for deciding whether supplemental imaging is justified because not all women with dense breasts have high interval cancer rates. BCSC 5-year risk combined with BI-RADS breast density can identify women at high risk for interval cancer to inform patient-provider discussions about alternative screening strategies. National Cancer Institute.

  8. Do Circumnuclear Dense Gas Disks Drive Mass Accretion onto Supermassive Black Holes?

    NASA Astrophysics Data System (ADS)

    Izumi, Takuma; Kawakatu, Nozomu; Kohno, Kotaro

    2016-08-01

    We present a positive correlation between the mass of dense molecular gas ({M}{{dense}}) of ˜100 pc scale circumnuclear disks (CNDs) and the black hole mass accretion rate ({\\dot{M}}{{BH}}) in a total of 10 Seyfert galaxies, based on data compiled from the literature and an archive (median aperture θ med = 220 pc). A typical {M}{{dense}} of CNDs is 107-8 {M}⊙ , estimated from the luminosity of the dense gas tracer, the HCN(1-0) emission line. Because dense molecular gas is the site of star formation, this correlation is virtually equivalent to the one between the nuclear star-formation rate and {\\dot{M}}{{BH}} revealed previously. Moreover, the {M}{{dense}}{--}{\\dot{M}}{{BH}} correlation was tighter for CND-scale gas than for the gas on kiloparsec or larger scales. This indicates that CNDs likely play an important role in fueling black holes, whereas greater than kiloparesec scale gas does not. To demonstrate a possible approach for studying the CND-scale accretion process with the Atacama Large Millimeter/submillimeter Array, we used a mass accretion model where angular momentum loss due to supernova explosions is vital. Based on the model prediction, we suggest that only the partial fraction of the mass accreted from the CND ({\\dot{M}}{{acc}}) is consumed as {\\dot{M}}{{BH}}. However, {\\dot{M}}{{acc}} agrees well with the total nuclear mass flow rate (I.e., {\\dot{M}}{{BH}} + outflow rate). Although these results are still tentative with large uncertainties, they support the view that star formation in CNDs can drive mass accretion onto supermassive black holes in Seyfert galaxies.

  9. Thick discs, and an outflow, of dense gas in the nuclei of nearby Seyfert galaxies

    NASA Astrophysics Data System (ADS)

    Lin, Ming-Yi; Davies, R. I.; Burtscher, L.; Contursi, A.; Genzel, R.; González-Alfonso, E.; Graciá-Carpio, J.; Janssen, A.; Lutz, D.; Orban de Xivry, G.; Rosario, D.; Schnorr-Müller, A.; Sternberg, A.; Sturm, E.; Tacconi, L.

    2016-05-01

    We discuss the dense molecular gas in central regions of nearby Seyfert galaxies, and report new arcsec resolution observations of HCN (1-0) and HCO+ (1-0) for three objects. In NGC 3079, the lines show complex profiles as a result of self-absorption and saturated continuum absorption. H13CN reveals the continuum absorption profile, with a peak close to the galaxy's systemic velocity that traces disc rotation, and a second feature with a blue wing extending to -350 km s-1 that most likely traces a nuclear outflow. The morphological and spectral properties of the emission lines allow us to constrain the dense gas dynamics. We combine our kinematic analysis for these three objects, as well as another with archival data, with a previous comparable analysis of four other objects, to create a sample of eight Seyferts. In seven of these, the emission line kinematics imply thick disc structures on radial scales of ˜100 pc, suggesting such structures are a common occurrence. We find a relation between the circum-nuclear LHCN and Mdyn that can be explained by a gas fraction of 10 per cent and a conversion factor αHCN ˜ 10 between gas mass and HCN luminosity. Finally, adopting a different perspective to probe the physical properties of the gas around active galactic nuclei, we report on an analysis of molecular line ratios which indicates that the clouds in this region are not self-gravitating.

  10. The Formation of Shell Galaxies Similar to NGC 7600 in the Cold Dark Matter Cosmogony

    NASA Astrophysics Data System (ADS)

    Cooper, Andrew P.; Martínez-Delgado, David; Helly, John; Frenk, Carlos; Cole, Shaun; Crawford, Ken; Zibetti, Stefano; Carballo-Bello, Julio A.; GaBany, R. Jay

    2011-12-01

    We present new deep observations of "shell" structures in the halo of the nearby elliptical galaxy NGC 7600, alongside a movie of galaxy formation in a cold dark matter (CDM) universe. The movie, based on an ab initio cosmological simulation, shows how continuous accretion of clumps of dark matter and stars creates a swath of diffuse circumgalactic structures. The disruption of a massive clump on a near-radial orbit creates a complex system of transient concentric shells which bare a striking resemblance to those of NGC 7600. With the aid of the simulation we interpret NGC 7600 in the context of the CDM model.

  11. Experimental realization of the analogy of quantum dense coding in classical optics

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Yang, Zhenwei; Sun, Yifan; Li, Pengyun

    2016-06-15

    We report on the experimental realization of the analogy of quantum dense coding in classical optical communication using classical optical correlations. Compared to quantum dense coding that uses pairs of photons entangled in polarization, we find that the proposed design exhibits many advantages. Considering that it is convenient to realize in optical communication, the attainable channel capacity in the experiment for dense coding can reach 2 bits, which is higher than that of the usual quantum coding capacity (1.585 bits). This increased channel capacity has been proven experimentally by transmitting ASCII characters in 12 quaternary digitals instead of the usualmore » 24 bits.« less

  12. Quark matter in the perturbation QCD model with a rapidly convergent matching-invariant running coupling

    NASA Astrophysics Data System (ADS)

    Xu, Jian-Feng; Luo, Yan-An; Li, Lei; Peng, Guang-Xiong

    The properties of dense quark matter are investigated in the perturbation theory with a rapidly convergent matching-invariant running coupling. The fast convergence is mainly due to the resummation of an infinite number of known logarithmic terms in a compact form. The only parameter in this model, the ratio of the renormalization subtraction point to the chemical potential, is restricted to be about 2.64 according to the Witten-Bodmer conjecture, which gives the maximum mass and the biggest radius of quark stars to be, respectively, two times the solar mass and 11.7km.

  13. Strangeness from SPS to FAIR: Searching for the onset of deconfinement

    NASA Astrophysics Data System (ADS)

    Friese, Volker

    2017-12-01

    Since the early days of heavy-ion physics, strangeness has been considered a sensitive probe of the state of matter created in nuclear collisions. This assessment still holds today, where we are witnessing renewed interest in collisions at moderate energies, manifested in the running or projected experimental programmes at RHIC, SPS, FAIR, and NICA. In this article, we will review the current understanding of strangeness production at lower energies and discuss how far future measurement of strange particles can contribute to understanding the properties of dense QCD matter and to the search for the onset of deconfinement.

  14. Nonempirical Semilocal Free-Energy Density Functional for Matter under Extreme Conditions

    DOE PAGES

    Karasiev, Valentin V.; Dufty, James W.; Trickey, S. B.

    2018-02-14

    The potential for density functional calculations to predict the properties of matter under extreme conditions depends crucially upon having a non-empirical approximate free energy functional valid over a wide range of state conditions. Unlike the ground-state case, no such free-energy exchange- correlation (XC) functional exists. We remedy that with systematic construction of a generalized gradient approximation XC free-energy functional based on rigorous constraints, including the free energy gradient expansion. The new functional provides the correct temperature dependence in the slowly varying regime and the correct zero-T, high-T, and homogeneous electron gas limits. Application in Kohn-Sham calculations for hot electrons inmore » a static fcc Aluminum lattice demon- strates the combined magnitude of thermal and gradient effects handled by this functional. Its accuracy in the increasingly important warm dense matter regime is attested by excellent agreement of the calculated deuterium equation of state with reference path integral Monte Carlo results at intermediate and elevated temperatures and by low density Al calculations over a wide T range.« less

  15. Nonempirical Semilocal Free-Energy Density Functional for Matter under Extreme Conditions

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Karasiev, Valentin V.; Dufty, James W.; Trickey, S. B.

    The potential for density functional calculations to predict the properties of matter under extreme conditions depends crucially upon having a non-empirical approximate free energy functional valid over a wide range of state conditions. Unlike the ground-state case, no such free-energy exchange- correlation (XC) functional exists. We remedy that with systematic construction of a generalized gradient approximation XC free-energy functional based on rigorous constraints, including the free energy gradient expansion. The new functional provides the correct temperature dependence in the slowly varying regime and the correct zero-T, high-T, and homogeneous electron gas limits. Application in Kohn-Sham calculations for hot electrons inmore » a static fcc Aluminum lattice demon- strates the combined magnitude of thermal and gradient effects handled by this functional. Its accuracy in the increasingly important warm dense matter regime is attested by excellent agreement of the calculated deuterium equation of state with reference path integral Monte Carlo results at intermediate and elevated temperatures and by low density Al calculations over a wide T range.« less

  16. Toward Superior Capacitive Energy Storage: Recent Advances in Pore Engineering for Dense Electrodes.

    PubMed

    Liu, Congcong; Yan, Xiaojun; Hu, Fei; Gao, Guohua; Wu, Guangming; Yang, Xiaowei

    2018-04-01

    With the rapid development of mobile electronics and electric vehicles, future electrochemical capacitors (ECs) need to store as much energy as possible in a rather limited space. As the core component of ECs, dense electrodes that have a high volumetric energy density and superior rate capability are the key to achieving improved energy storage. Here, the significance of and recent progress in the high volumetric performance of dense electrodes are presented. Furthermore, dense yet porous electrodes, as the critical precondition for realizing superior electrochemical capacitive energy, have become a scientific challenge and an attractive research focus. From a pore-engineering perspective, insight into the guidelines of engineering the pore size, connectivity, and wettability is provided to design dense electrodes with different porous architectures toward high-performance capacitive energy storage. The current challenges and future opportunities toward dense electrodes are discussed and include the construction of an orderly porous structure with an appropriate gradient, the coupling of pore sizes with the solvated cations and anions, and the design of coupled pores with diverse electrolyte ions. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. First experimental demonstration of magnetic-field assisted fast heating of a dense plasma core

    NASA Astrophysics Data System (ADS)

    Fujioka, Shinsuke; Sakata, Shohei; Lee, Seung Ho; Matsuo, Kazuki; Sawada, Hiroshi; Iwasa, Yuki; Law, King Fai Farley; Morita, Hitoki; Kojima, Sadaoki; Abe, Yuki; Yao, Akira; Hata, Masayasu; Johzaki, Tomoyuki; Sunahara, Atsushi; Ozaki, Tetsuo; Sakagami, Hitoshi; Morace, Alessio; Arikawa, Yasunobu; Yogo, Akifumi; Nishimura, Hiroaki; Nakai, Mitsuo; Shiraga, Hiroyuki; Sentoku, Yasuhiko; Nagatomo, Hideo; Azechi, Hiroshi; Firex Project Team

    2016-10-01

    Fast heating of a dense plasma core by an energetic electron beam is being studied on GEKKO-LFEX laser facility. Here, we introduce a laser-driven kilo-tesla external magnetic field to guide the diverging electron beam to the dense plasma core. This involve placing a spherical target in the magnetic field, compressing it with the GEKKO-XII laser beams and then using the LFEX laser beams injected into the dense plasma to generate the electron beam which do the fast heating. Cu-Ka emission is used to visualize transport or heating processes of a dense plasma. X-ray spectrum from a highly ionized Cu ions indicates several keV of the temperature increment induced by the LFEX.

  18. Nucleon effective masses in neutron-rich matter

    NASA Astrophysics Data System (ADS)

    Li, Bao-An; Cai, Bao-Jun; Chen, Lie-Wen; Xu, Jun

    2018-03-01

    transition in neutron-rich matter. Moreover, they influence the dynamics and isospin-sensitive observables of heavy-ion collisions through both the Vlasov term and the collision integrals of the Boltzmann-Uehling-Uhlenbeck transport equation. We review here some of the significant progresses made in recent years by the nuclear physics community in resolving some of the hotly debated and longstanding issues regarding nucleon effective masses especially in dense neutron-rich matter. We also point out some of the remaining key issues requiring further investigations in the era of high precision experiments using advanced rare isotope beams.

  19. Preparation of a dense, polycrystalline ceramic structure

    DOEpatents

    Cooley, Jason; Chen, Ching-Fong; Alexander, David

    2010-12-07

    Ceramic nanopowder was sealed inside a metal container under a vacuum. The sealed evacuated container was forced through a severe deformation channel at an elevated temperature below the melting point of the ceramic nanopowder. The result was a dense nanocrystalline ceramic structure inside the metal container.

  20. Simulation of a Driven Dense Granular Gas

    NASA Astrophysics Data System (ADS)

    Bizon, Chris; Shattuck, M. D.; Swift, J. B.; Swinney, Harry L.

    1998-11-01

    Event driven particle simulations quantitatively reproduce the experimental results on vibrated granular layers, including the formation of standing wave patterns(C. Bizon, M.D. Shattuck, J.B. Swift, W.D. McCormick, and H.L. Swinney, Phys. Rev. Lett. 80), pp. 57-60 (1998). and secondary instabilities(J.R. deBruyn, C. Bizon, M.D. Shattuck, D. Goldman, J.B. Swift, and H.L. Swinney, Phys. Rev. Lett. 81) (1998), to appear. . In these simulations the velocity distributions are nearly Gaussian when scaled with the local fluctuational kinetic energy (granular temperature); this suggests that inelastic dense gas kinetic theory is applicable. We perform simulations of a two-dimensional granular gas that is homogeneously driven with fluctuating forces. We find that the equation of state differs from that of an elastic dense gas and that this difference is due to a change in the distribution of relative velocities at collisions. Granular thermal conductivity and viscosity are measured by allowing the fluctuating forces to have large scale spatial gradients.

  1. An Integrative Experiential Learning Project in the Undergraduate Branding Course: Creating a Marketing Department Brochure

    ERIC Educational Resources Information Center

    Craciun, Georgiana; Corrigan, Hope Bober

    2010-01-01

    This article introduces a selective approach to curriculum integration that consists of linking the subject matter of a new course with knowledge and skills acquired in two or more completed courses to create a deeper and richer learning experience. Benefits and challenges of the selective approach and an example of implementing an integrative…

  2. Reply to 'Comment on 'Quantum dense key distribution''

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Degiovanni, I.P.; Berchera, I. Ruo; Castelletto, S.

    2005-01-01

    In this Reply we propose a modified security proof of the quantum dense key distribution protocol, detecting also the eavesdropping attack proposed by Wojcik in his Comment [Wojcik, Phys. Rev. A 71, 016301 (2005)].

  3. Dense ceramic membranes for converting methane to syngas

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Balachandran, U.; Dusek, J.T.; Picciolo, J.J.

    1995-07-01

    Dense mixed-oxide ceramics capable of conducting both electrons and oxygen ions are promising materials for partial oxygenation of methane to syngas. We are particularly interested in an oxide based on the Sr-Fe-Co-O system. Dense ceramic membrane tubes have been fabricated by a plastic extrusion technique. The sintered tubes were then used to selectively transport oxygen from air through the membrane to make syngas without the use of external electrodes. The sintered tubes have operated for >1000 h, and methane conversion efficiencies of >98% have been observed. Mechanical properties, structural integrity of the tubes during reactor operation, results of methane conversion,more » selectivity of methane conversion products, oxygen permeation, and fabrication of multichannel configurations for large-scale production of syngas will be presented.« less

  4. A look at scalable dense linear algebra libraries

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Dongarra, J.J.; Van de Geijn, R.A.; Walker, D.W.

    1992-01-01

    We discuss the essential design features of a library of scalable software for performing dense linear algebra computations on distributed memory concurrent computers. The square block scattered decomposition is proposed as a flexible and general-purpose way of decomposing most, if not all, dense matrix problems. An object- oriented interface to the library permits more portable applications to be written, and is easy to learn and use, since details of the parallel implementation are hidden from the user. Experiments on the Intel Touchstone Delta system with a prototype code that uses the square block scattered decomposition to perform LU factorization aremore » presented and analyzed. It was found that the code was both scalable and efficient, performing at about 14 GFLOPS (double precision) for the largest problem considered.« less

  5. A look at scalable dense linear algebra libraries

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Dongarra, J.J.; Van de Geijn, R.A.; Walker, D.W.

    1992-08-01

    We discuss the essential design features of a library of scalable software for performing dense linear algebra computations on distributed memory concurrent computers. The square block scattered decomposition is proposed as a flexible and general-purpose way of decomposing most, if not all, dense matrix problems. An object- oriented interface to the library permits more portable applications to be written, and is easy to learn and use, since details of the parallel implementation are hidden from the user. Experiments on the Intel Touchstone Delta system with a prototype code that uses the square block scattered decomposition to perform LU factorization aremore » presented and analyzed. It was found that the code was both scalable and efficient, performing at about 14 GFLOPS (double precision) for the largest problem considered.« less

  6. Shock-adiabatic to quasi-isentropic compression of warm dense helium up to 150 GPa

    NASA Astrophysics Data System (ADS)

    Zheng, J.; Chen, Q. F.; Gu, Y. J.; Li, J. T.; Li, Z. G.; Li, C. J.; Chen, Z. Y.

    2017-06-01

    Multiple reverberation compression can achieve higher pressure, higher temperature, but lower entropy. It is available to provide an important validation for the elaborate and wider planetary models and simulate the inertial confinement fusion capsule implosion process. In the work, we have developed the thermodynamic and optical properties of helium from shock-adiabatic to quasi-isentropic compression by means of a multiple reverberation technique. By this technique, the initial dense gaseous helium was compressed to high pressure and high temperature and entered the warm dense matter (WDM) region. The experimental equation of state (EOS) of WDM helium in the pressure-density-temperature (P-ρ -T) range of 1 -150 GPa , 0.1 -1.1 g c m-3 , and 4600-24 000 K were measured. The optical radiations emanating from the WDM helium were recorded, and the particle velocity profiles detecting from the sample/window interface were obtained successfully up to 10 times compression. The optical radiation results imply that dense He has become rather opaque after the 2nd compression with a density of about 0.3 g c m-3 and a temperature of about 1 eV. The opaque states of helium under multiple compression were analyzed by the particle velocity measurements. The multiple compression technique could efficiently enhanced the density and the compressibility, and our multiple compression ratios (ηi=ρi/ρ0,i =1 -10 ) of helium are greatly improved from 3.5 to 43 based on initial precompressed density (ρ0) . For the relative compression ratio (ηi'=ρi/ρi -1) , it increases with pressure in the lower density regime and reversely decreases in the higher density regime, and a turning point occurs at the 3rd and 4th compression states under the different loading conditions. This nonmonotonic evolution of the compression is controlled by two factors, where the excitation of internal degrees of freedom results in the increasing compressibility and the repulsive interactions between the

  7. Search for gamma-ray emission from dark matter annihilation in the Small Magellanic Cloud with the Fermi Large Area Telescope

    DOE PAGES

    Caputo, Regina; Buckley, Matthew R.; Martin, Pierrick; ...

    2016-03-22

    The Small Magellanic Cloud (SMC) is the second-largest satellite galaxy of the Milky Way and is only 60 kpc away. As a nearby, massive, and dense object with relatively low astrophysical backgrounds, it is a natural target for dark matter indirect detection searches. In this work, we use six years of Pass 8 data from the Fermi Large Area Telescope to search for gamma-ray signals of dark matter annihilation in the SMC. Using data-driven fits to the gamma-ray backgrounds, and a combination of N-body simulations and direct measurements of rotation curves to estimate the SMC DM density profile, we found that themore » SMC was well described by standard astrophysical sources, and no signal from dark matter annihilation was detected. We set conservative upper limits on the dark matter annihilation cross section. Furthermore, these constraints are in agreement with stronger constraints set by searches in the Large Magellanic Cloud and approach the canonical thermal relic cross section at dark matter masses lower than 10 GeV in the bb¯ and τ +τ - channels.« less

  8. Acceptance procedures for dense-graded mixes : literature review.

    DOT National Transportation Integrated Search

    2001-03-01

    Recent literature related to acceptance procedures for dense-graded mixtures is summarized. Current state of practice and development of acceptance procedures are reviewed. Many agencies are reducing the number of process control-related parameters i...

  9. IrisDenseNet: Robust Iris Segmentation Using Densely Connected Fully Convolutional Networks in the Images by Visible Light and Near-Infrared Light Camera Sensors

    PubMed Central

    Arsalan, Muhammad; Naqvi, Rizwan Ali; Kim, Dong Seop; Nguyen, Phong Ha; Owais, Muhammad; Park, Kang Ryoung

    2018-01-01

    The recent advancements in computer vision have opened new horizons for deploying biometric recognition algorithms in mobile and handheld devices. Similarly, iris recognition is now much needed in unconstraint scenarios with accuracy. These environments make the acquired iris image exhibit occlusion, low resolution, blur, unusual glint, ghost effect, and off-angles. The prevailing segmentation algorithms cannot cope with these constraints. In addition, owing to the unavailability of near-infrared (NIR) light, iris recognition in visible light environment makes the iris segmentation challenging with the noise of visible light. Deep learning with convolutional neural networks (CNN) has brought a considerable breakthrough in various applications. To address the iris segmentation issues in challenging situations by visible light and near-infrared light camera sensors, this paper proposes a densely connected fully convolutional network (IrisDenseNet), which can determine the true iris boundary even with inferior-quality images by using better information gradient flow between the dense blocks. In the experiments conducted, five datasets of visible light and NIR environments were used. For visible light environment, noisy iris challenge evaluation part-II (NICE-II selected from UBIRIS.v2 database) and mobile iris challenge evaluation (MICHE-I) datasets were used. For NIR environment, the institute of automation, Chinese academy of sciences (CASIA) v4.0 interval, CASIA v4.0 distance, and IIT Delhi v1.0 iris datasets were used. Experimental results showed the optimal segmentation of the proposed IrisDenseNet and its excellent performance over existing algorithms for all five datasets. PMID:29748495

  10. IrisDenseNet: Robust Iris Segmentation Using Densely Connected Fully Convolutional Networks in the Images by Visible Light and Near-Infrared Light Camera Sensors.

    PubMed

    Arsalan, Muhammad; Naqvi, Rizwan Ali; Kim, Dong Seop; Nguyen, Phong Ha; Owais, Muhammad; Park, Kang Ryoung

    2018-05-10

    The recent advancements in computer vision have opened new horizons for deploying biometric recognition algorithms in mobile and handheld devices. Similarly, iris recognition is now much needed in unconstraint scenarios with accuracy. These environments make the acquired iris image exhibit occlusion, low resolution, blur, unusual glint, ghost effect, and off-angles. The prevailing segmentation algorithms cannot cope with these constraints. In addition, owing to the unavailability of near-infrared (NIR) light, iris recognition in visible light environment makes the iris segmentation challenging with the noise of visible light. Deep learning with convolutional neural networks (CNN) has brought a considerable breakthrough in various applications. To address the iris segmentation issues in challenging situations by visible light and near-infrared light camera sensors, this paper proposes a densely connected fully convolutional network (IrisDenseNet), which can determine the true iris boundary even with inferior-quality images by using better information gradient flow between the dense blocks. In the experiments conducted, five datasets of visible light and NIR environments were used. For visible light environment, noisy iris challenge evaluation part-II (NICE-II selected from UBIRIS.v2 database) and mobile iris challenge evaluation (MICHE-I) datasets were used. For NIR environment, the institute of automation, Chinese academy of sciences (CASIA) v4.0 interval, CASIA v4.0 distance, and IIT Delhi v1.0 iris datasets were used. Experimental results showed the optimal segmentation of the proposed IrisDenseNet and its excellent performance over existing algorithms for all five datasets.

  11. Grain Growth and Silicates in Dense Clouds

    NASA Technical Reports Server (NTRS)

    Pendeleton, Yvonne J.; Chiar, J. E.; Ennico, K.; Boogert, A.; Greene, T.; Knez, C.; Lada, C.; Roellig, T.; Tielens, A.; Werner, M.; hide

    2006-01-01

    Interstellar silicates are likely to be a part of all grains responsible for visual extinction (Av) in the diffuse interstellar medium (ISM) and dense clouds. A correlation between Av and the depth of the 9.7 micron silicate feature (measured as optical depth, tau(9.7)) is expected if the dust species are well 'mixed. In the di&se ISM, such a correlation is observed for lines of sight in the solar neighborhood. A previous study of the silicate absorption feature in the Taurus dark cloud showed a tendency for the correlation to break down at high Av (Whittet et al. 1988, MNRAS, 233,321), but the scatter was large. We have acquired Spitzer Infrared Spectrograph data of several lines of sight in the IC 5 146, Barnard 68, Chameleon I and Serpens dense clouds. Our data set spans an Av range between 2 and 35 magnitudes. All lines of sight show the 9.7 micron silicate feature. The Serpens data appear to follow the diffuse ISM correlation line whereas the data for the other clouds show a non-linear correlation between the depth of the silicate feature relative to Av, much like the trend observed in the Taurus data. In fact, it appears that for visual extinctions greater than about 10 mag, tau(9.7) begins to level off. This decrease in the growth of the depth of the 9.7 micron feature with increasing Av could indicate the effects of grain growth in dense clouds. In this poster, we explore the possibility that grain growth causes an increase in opacity (Av) without causing a corresponding increase in tau(9.7).

  12. Hypernuclei and the hyperon problem in neutron stars

    DOE PAGES

    Bedaque, Paulo F.; Steiner, Andrew W.

    2015-08-17

    The likely presence ofmore » $$\\Lambda$$ baryons in dense hadronic matter tends to soften the equation of state to an extend that the observed heaviest neutron stars are difficult to explain. Here we analyze this "hyperon problem" with a phenomenological approach. First, we review what can be learned about the interaction of $$\\Lambda$$ particle with dense matter from the observed hypernuclei and extend this phenomenological analysis to asymmetric matter. We add to this the current knowledge on non-strange dense matter, including its uncertainties, to conclude that the interaction between $$\\Lambda$$s and dense matter has to become repulsive at densities below three times the nuclear saturation density.« less

  13. The JCMT Gould Belt Survey: Dense Core Clusters in Orion B

    NASA Astrophysics Data System (ADS)

    Kirk, H.; Johnstone, D.; Di Francesco, J.; Lane, J.; Buckle, J.; Berry, D. S.; Broekhoven-Fiene, H.; Currie, M. J.; Fich, M.; Hatchell, J.; Jenness, T.; Mottram, J. C.; Nutter, D.; Pattle, K.; Pineda, J. E.; Quinn, C.; Salji, C.; Tisi, S.; Hogerheijde, M. R.; Ward-Thompson, D.; The JCMT Gould Belt Survey Team

    2016-04-01

    The James Clerk Maxwell Telescope Gould Belt Legacy Survey obtained SCUBA-2 observations of dense cores within three sub-regions of Orion B: LDN 1622, NGC 2023/2024, and NGC 2068/2071, all of which contain clusters of cores. We present an analysis of the clustering properties of these cores, including the two-point correlation function and Cartwright’s Q parameter. We identify individual clusters of dense cores across all three regions using a minimal spanning tree technique, and find that in each cluster, the most massive cores tend to be centrally located. We also apply the independent M-Σ technique and find a strong correlation between core mass and the local surface density of cores. These two lines of evidence jointly suggest that some amount of mass segregation in clusters has happened already at the dense core stage.

  14. Dense gas and star formation in individual Giant Molecular Clouds in M31

    NASA Astrophysics Data System (ADS)

    Viaene, S.; Forbrich, J.; Fritz, J.

    2018-04-01

    Studies both of entire galaxies and of local Galactic star formation indicate a dependency of a molecular cloud's star formation rate (SFR) on its dense gas mass. In external galaxies, such measurements are derived from HCN(1-0) observations, usually encompassing many Giant Molecular Clouds (GMCs) at once. The Andromeda galaxy (M31) is a unique laboratory to study the relation of the SFR and HCN emission down to GMC scales at solar-like metallicities. In this work, we correlate our composite SFR determinations with archival HCN, HCO+, and CO observations, resulting in a sample of nine reasonably representative GMCs. We find that, at the scale of individual clouds, it is important to take into account both obscured and unobscured star formation to determine the SFR. When correlated against the dense-gas mass from HCN, we find that the SFR is low, in spite of these refinements. We nevertheless retrieve an SFR-dense-gas mass correlation, confirming that these SFR tracers are still meaningful on GMC scales. The correlation improves markedly when we consider the HCN/CO ratio instead of HCN by itself. This nominally indicates a dependency of the SFR on the dense-gas fraction, in contradiction to local studies. However, we hypothesize that this partly reflects the limited dynamic range in dense-gas mass, and partly that the ratio of single-pointing HCN and CO measurements may be less prone to systematics like sidelobes. In this case, the HCN/CO ratio would importantly be a better empirical measure of the dense-gas content itself.

  15. Tripolar vortex formation in dense quantum plasma with ion-temperature-gradients

    NASA Astrophysics Data System (ADS)

    Qamar, Anisa; Ata-ur-Rahman, Mirza, Arshad M.

    2012-05-01

    We have derived system of nonlinear equations governing the dynamics of low-frequency electrostatic toroidal ion-temperature-gradient mode for dense quantum magnetoplasma. For some specific profiles of the equilibrium density, temperature, and ion velocity gradients, the nonlinear equations admit a stationary solution in the form of a tripolar vortex. These results are relevant to understand nonlinear structure formation in dense quantum plasmas in the presence of equilibrium ion-temperature and density gradients.

  16. Seven enzymes create extraordinary molecular complexity in an uncultivated bacterium

    NASA Astrophysics Data System (ADS)

    Freeman, Michael F.; Helf, Maximilian J.; Bhushan, Agneya; Morinaka, Brandon I.; Piel, Jörn

    2017-04-01

    Uncultivated bacteria represent a massive resource of new enzymes and bioactive metabolites, but such bacteria remain functionally enigmatic. Polytheonamides are potent peptide cytotoxins produced by uncultivated bacteria that exist as symbionts in a marine sponge. Outside glycobiology, polytheonamides represent the most heavily post-translationally modified biomolecules that are derived from amino acids. The biosynthesis of polytheonamides involves up to 50 site-specific modifications to create a membrane-spanning β-helical structure. Here, we provide functional evidence that only seven enzymes are necessary for this process. They iteratively catalyse epimerization, methylation and hydroxylation of diverse amino acids. To reconstitute C-methylation, we employed the rarely used heterologous host Rhizobium leguminosarum to invoke the activities of two cobalamin-dependent C-methyltransferases. We observed 44 of the modifications to systematically unravel the biosynthesis of one of the most densely modified and metabolically obscure ribosome-derived molecules found in nature.

  17. 40 CFR 49.126 - Rule for limiting fugitive particulate matter emissions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., and other surfaces that can create airborne dust. (iii) Full or partial enclosure of materials... particulate matter from becoming airborne. (iv) Implementation of good housekeeping practices to avoid or minimize the accumulation of dusty materials that have the potential to become airborne, and the prompt...

  18. A Study on Urban Road Traffic Safety Based on Matter Element Analysis

    PubMed Central

    Hu, Qizhou; Zhou, Zhuping; Sun, Xu

    2014-01-01

    This paper examines a new evaluation of urban road traffic safety based on a matter element analysis, avoiding the difficulties found in other traffic safety evaluations. The issue of urban road traffic safety has been investigated through the matter element analysis theory. The chief aim of the present work is to investigate the features of urban road traffic safety. Emphasis was placed on the construction of a criterion function by which traffic safety achieved a hierarchical system of objectives to be evaluated. The matter element analysis theory was used to create the comprehensive appraisal model of urban road traffic safety. The technique was used to employ a newly developed and versatile matter element analysis algorithm. The matter element matrix solves the uncertainty and incompatibility of the evaluated factors used to assess urban road traffic safety. The application results showed the superiority of the evaluation model and a didactic example was included to illustrate the computational procedure. PMID:25587267

  19. Why power matters: creating a foundation of mutual support in couple relationships.

    PubMed

    Knudson-Martin, Carmen

    2013-03-01

    Research shows that equal power helps couples create intimacy and relationship success. However, though couples increasingly desire equal relationships, cultural models of mutual support are not well developed. Clinicians often approach heterosexual couple therapy as though partners are inherently equal, thus reinforcing unacknowledged gender inequities. This article examines research that shows why power imbalances are destructive to intimate relationships and focuses on four gender-related aspects of mutual support: (a) shared relational responsibility, (b) mutual vulnerability, (c) mutual attunement, and (d) shared influence. Case examples illustrate how socio-emotional attunement, interrupting the flow of power, and introducing alternative relational experience help couple therapists identify and address power disparities in these important relational processes. Encouraging the powerful person to take relational initiative and introducing alternative gender discourse are especially important. © FPI, Inc.

  20. Shear dispersion in dense granular flows

    DOE PAGES

    Christov, Ivan C.; Stone, Howard A.

    2014-04-18

    We formulate and solve a model problem of dispersion of dense granular materials in rapid shear flow down an incline. The effective dispersivity of the depth-averaged concentration of the dispersing powder is shown to vary as the Péclet number squared, as in classical Taylor–Aris dispersion of molecular solutes. An extension to generic shear profiles is presented, and possible applications to industrial and geological granular flows are noted.

  1. Free-free opacity in dense plasmas with an average atom model

    DOE PAGES

    Shaffer, Nathaniel R.; Ferris, Natalie G.; Colgan, James Patrick; ...

    2017-02-28

    A model for the free-free opacity of dense plasmas is presented. The model uses a previously developed average atom model, together with the Kubo-Greenwood model for optical conductivity. This, in turn, is used to calculate the opacity with the Kramers-Kronig dispersion relations. Furthermore, comparisons to other methods for dense deuterium results in excellent agreement with DFT-MD simulations, and reasonable agreement with a simple Yukawa screening model corrected to satisfy the conductivity sum rule.

  2. Free-free opacity in dense plasmas with an average atom model

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Shaffer, Nathaniel R.; Ferris, Natalie G.; Colgan, James Patrick

    A model for the free-free opacity of dense plasmas is presented. The model uses a previously developed average atom model, together with the Kubo-Greenwood model for optical conductivity. This, in turn, is used to calculate the opacity with the Kramers-Kronig dispersion relations. Furthermore, comparisons to other methods for dense deuterium results in excellent agreement with DFT-MD simulations, and reasonable agreement with a simple Yukawa screening model corrected to satisfy the conductivity sum rule.

  3. Densely ionizing radiation affects DNA methylation of selective LINE-1 elements

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Prior, Sara; Miousse, Isabelle R.

    Long Interspersed Nucleotide Element 1 (LINE-1) retrotransposons are heavily methylated and are the most abundant transposable elements in mammalian genomes. Here, we investigated the differential DNA methylation within the LINE-1 under normal conditions and in response to environmentally relevant doses of sparsely and densely ionizing radiation. We demonstrate that DNA methylation of LINE-1 elements in the lungs of C57BL6 mice is dependent on their evolutionary age, where the elder age of the element is associated with the lower extent of DNA methylation. Exposure to 5-aza-2′-deoxycytidine and methionine-deficient diet affected DNA methylation of selective LINE-1 elements in an age- and promotermore » type-dependent manner. Exposure to densely IR, but not sparsely IR, resulted in DNA hypermethylation of older LINE-1 elements, while the DNA methylation of evolutionary younger elements remained mostly unchanged. We also demonstrate that exposure to densely IR increased mRNA and protein levels of LINE-1 via the loss of the histone H3K9 dimethylation and an increase in the H3K4 trimethylation at the LINE-1 5′-untranslated region, independently of DNA methylation. Our findings suggest that DNA methylation is important for regulation of LINE-1 expression under normal conditions, but histone modifications may dictate the transcriptional activity of LINE-1 in response to exposure to densely IR. - Highlights: • DNA methylation of LINE-1 elements is dependent on their evolutionary age. • Densely ionizing radiation affects DNA methylation of selective LINE-1 elements. • Radiation-induced reactivation of LINE-1 is DNA methylation-independent. • Histone modifications dictate the transcriptional activity of LINE-1.« less

  4. Dense understory dwarf bamboo alters the retention of canopy tree seeds

    NASA Astrophysics Data System (ADS)

    Qian, Feng; Zhang, Tengda; Guo, Qinxue; Tao, Jianping

    2016-05-01

    Tree seed retention is thought to be an important factor in the process of forest community regeneration. Although dense understory dwarf bamboo has been considered to have serious negative effects on the regeneration of forest community species, little attention has been paid to the relationship between dwarf bamboo and seed retention. In a field experiment we manipulated the density of Fargesia decurvata, a common understory dwarf bamboo, to investigate the retention of seeds from five canopy tree species in an evergreen and deciduous broad-leaved mixed forest in Jinfoshan National Nature Reserve, SW China. We found that the median survival time and retention ratio of seeds increased with the increase in bamboo density. Fauna discriminately altered seed retention in bamboo groves of different densities. Arthropods reduced seed survival the most, and seeds removed decreased with increasing bamboo density. Birds removed or ate more seeds in groves of medium bamboo density and consumed fewer seeds in dense or sparse bamboo habitats. Rodents removed a greater number of large and highly profitable seeds in dense bamboo groves but more small and thin-husked seeds in sparse bamboo groves. Seed characteristics, including seed size, seed mass and seed profitability, were important factors affecting seed retention. The results suggested that dense understory dwarf bamboo not only increased seeds concealment and reduced the probability and speed of seed removal but also influenced the trade-off between predation and risk of animal predatory strategies, thereby impacting the quantity and composition of surviving seeds. Our results also indicated that dense understory dwarf bamboo and various seed characteristics can provide good opportunities for seed storage and seed germination and has a potential positive effect on canopy tree regeneration.

  5. The EARP Complex and Its Interactor EIPR-1 Are Required for Cargo Sorting to Dense-Core Vesicles

    PubMed Central

    Topalidou, Irini; Cattin-Ortolá, Jérôme; MacCoss, Michael J.

    2016-01-01

    The dense-core vesicle is a secretory organelle that mediates the regulated release of peptide hormones, growth factors, and biogenic amines. Dense-core vesicles originate from the trans-Golgi of neurons and neuroendocrine cells, but it is unclear how this specialized organelle is formed and acquires its specific cargos. To identify proteins that act in dense-core vesicle biogenesis, we performed a forward genetic screen in Caenorhabditis elegans for mutants defective in dense-core vesicle function. We previously reported the identification of two conserved proteins that interact with the small GTPase RAB-2 to control normal dense-core vesicle cargo-sorting. Here we identify several additional conserved factors important for dense-core vesicle cargo sorting: the WD40 domain protein EIPR-1 and the endosome-associated recycling protein (EARP) complex. By assaying behavior and the trafficking of dense-core vesicle cargos, we show that mutants that lack EIPR-1 or EARP have defects in dense-core vesicle cargo-sorting similar to those of mutants in the RAB-2 pathway. Genetic epistasis data indicate that RAB-2, EIPR-1 and EARP function in a common pathway. In addition, using a proteomic approach in rat insulinoma cells, we show that EIPR-1 physically interacts with the EARP complex. Our data suggest that EIPR-1 is a new interactor of the EARP complex and that dense-core vesicle cargo sorting depends on the EARP-dependent trafficking of cargo through an endosomal sorting compartment. PMID:27191843

  6. Dense Plasma Focus: physics and applications (radiation material science, single-shot disclosure of hidden illegal objects, radiation biology and medicine, etc.)

    NASA Astrophysics Data System (ADS)

    Gribkov, V. A.; Miklaszewski, R.; Paduch, M.; Zielinska, E.; Chernyshova, M.; Pisarczyk, T.; Pimenov, V. N.; Demina, E. V.; Niemela, J.; Crespo, M.-L.; Cicuttin, A.; Tomaszewski, K.; Sadowski, M. J.; Skladnik-Sadowska, E.; Pytel, K.; Zawadka, A.; Giannini, G.; Longo, F.; Talab, A.; Ul'yanenko, S. E.

    2015-03-01

    The paper presents some outcomes obtained during the year of 2013 of the activity in the frame of the International Atomic Energy Agency Co-ordinated research project "Investigations of Materials under High Repetition and Intense Fusion-Relevant Pulses". The main results are related to the effects created at the interaction of powerful pulses of different types of radiation (soft and hard X-rays, hot plasma and fast ion streams, neutrons, etc. generated in Dense Plasma Focus (DPF) facilities) with various materials including those that are counted as perspective ones for their use in future thermonuclear reactors. Besides we discuss phenomena observed at the irradiation of biological test objects. We examine possible applications of nanosecond powerful pulses of neutrons to the aims of nuclear medicine and for disclosure of hidden illegal objects. Special attention is devoted to discussions of a possibility to create extremely large and enormously diminutive DPF devices and probabilities of their use in energetics, medicine and modern electronics.

  7. Cereal Leaf Beetle (Coleoptera: Chrysomelidae) Regional Dispersion and Relationship With Wheat Stand Denseness.

    PubMed

    Reisig, Dominic D; Bacheler, Jack S; Herbert, D Ames; Heiniger, Ron; Kuhar, Thomas; Malone, Sean; Philips, Chris; Tilley, M Scott

    2017-06-01

    Cereal leaf beetle, Oulema melanopus L., is a pest of small grains and the literature conflicts on whether it is more abundant in sparse or dense stands of wheat. Our objectives were to determine the impact of stand denseness on cereal leaf beetle abundance and to investigate the regional dispersion of cereal leaf beetles across North Carolina and Virginia. One-hundred twenty fields were sampled across North Carolina and Virginia during 2011 for stand denseness, and cereal leaf beetle eggs, larvae, and adults. Two small-plot wheat experiments were planted in North Carolina using a low and a high seeding rate. Main plots were split, with one receiving a single nitrogen application and one receiving two. Egg density, but not larva or adult density, was positively correlated with stand denseness in the regional survey. Furthermore, regional spatial patterns of aggregation were noted for both stand denseness and egg number. In the small-plot experiments, seeding rate influenced stand denseness, but not nitrogen application. In one experiment, egg densities per unit area were higher in denser wheat, while in the other experiment, egg densities per tiller were lower in denser wheat. Larvae were not influenced by any factor. Overall, there were more cereal leaf beetle eggs in denser wheat stands. Previous observations that sparse stands of wheat are more prone to cereal leaf beetle infestation can be attributed to the fact that sparser stands have fewer tillers, which increases the cereal leaf beetle to tiller ratio compared with denser stands. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  8. Coupled modes in magnetized dense plasma with relativistic-degenerate electrons

    NASA Astrophysics Data System (ADS)

    Khan, S. A.

    2012-01-01

    Low frequency electrostatic and electromagnetic waves are investigated in ultra-dense quantum magnetoplasma with relativistic-degenerate electron and non-degenerate ion fluids. The dispersion relation is derived for mobile as well as immobile ions by employing hydrodynamic equations for such plasma under the influence of electromagnetic forces and pressure gradient of relativistic-degenerate Fermi gas of electrons. The result shows the coexistence of shear Alfven and ion modes with relativistically modified dispersive properties. The relevance of results to the dense degenerate plasmas of astrophysical origin (for instance, white dwarf stars) is pointed out with brief discussion on ultra-relativistic and non-relativistic limits.

  9. Phase transitions, interparticle correlations, and elementary processes in dense plasmas

    NASA Astrophysics Data System (ADS)

    Ichimaru, Setsuo

    2017-12-01

    Astrophysical dense plasmas are those we find in the interiors, surfaces, and outer envelopes of stellar objects such as neutron stars, white dwarfs, the Sun, and giant planets. Condensed plasmas in the laboratory settings include those in ultrahigh-pressure metal-physics experiments undertaken for realization of metallic hydrogen. We review basic physics issues studied in the past 60 some years on the phase transitions, the interparticle correlations, and the elementary processes in dense plasmas, through survey on scattering of electromagnetic waves, equations of state, phase diagrams, transport processes, stellar and planetary magnetisms, and thermo- and pycnonuclear reactions.

  10. Evolution of dense spatially modulated electron bunches

    NASA Astrophysics Data System (ADS)

    Balal, N.; Bratman, V. L.; Friedman, A.

    2018-03-01

    An analytical theory describing the dynamics of relativistic moving 1D electron pulses (layers) with the density modulation affected by a space charge has been revised and generalized for its application to the formation of dense picosecond bunches from linear accelerators with laser-driven photo injectors, and its good agreement with General Particle Tracer simulations has been demonstrated. Evolution of quasi-one-dimensional bunches (disks), for which the derived formulas predict longitudinal expansion, is compared with that for thin and long electron cylinders (threads), for which the excitation of non-linear waves with density spikes was found earlier by Musumeci et al. [Phys. Rev. Lett. 106(18), 184801 (2011)] and Musumeci et al. [Phys. Rev. Spec. Top. -Accel. Beams 16(10), 100701 (2013)]. Both types of bunches can be used for efficiency enhancement of THz sources based on the Doppler frequency up-shifted coherent spontaneous radiation of electrons. Despite the strong Coulomb repulsion, the periodicity of a preliminary modulation in dense 1D layers persists during their expansion in the most interesting case of a relatively small change in particle energy. However, the period of modulation increases and its amplitude decreases in time. In the case of a large change in electron energy, the uniformity of periodicity is broken due to different relativistic changes in longitudinal scales along the bunch: the "period" of modulation decreases and its amplitude increases from the rear to the front boundary. Nevertheless, the use of relatively long electron bunches with a proper preliminary spatial modulation of density can provide a significantly higher power and a narrower spectrum of coherent spontaneous radiation of dense bunches than in the case of initially short single bunches with the same charge.

  11. Nuclear quantum dynamics in dense hydrogen

    PubMed Central

    Kang, Dongdong; Sun, Huayang; Dai, Jiayu; Chen, Wenbo; Zhao, Zengxiu; Hou, Yong; Zeng, Jiaolong; Yuan, Jianmin

    2014-01-01

    Nuclear dynamics in dense hydrogen, which is determined by the key physics of large-angle scattering or many-body collisions between particles, is crucial for the dynamics of planet's evolution and hydrodynamical processes in inertial confinement confusion. Here, using improved ab initio path-integral molecular dynamics simulations, we investigated the nuclear quantum dynamics regarding transport behaviors of dense hydrogen up to the temperatures of 1 eV. With the inclusion of nuclear quantum effects (NQEs), the ionic diffusions are largely higher than the classical treatment by the magnitude from 20% to 146% as the temperature is decreased from 1 eV to 0.3 eV at 10 g/cm3, meanwhile, electrical and thermal conductivities are significantly lowered. In particular, the ionic diffusion is found much larger than that without NQEs even when both the ionic distributions are the same at 1 eV. The significant quantum delocalization of ions introduces remarkably different scattering cross section between protons compared with classical particle treatments, which explains the large difference of transport properties induced by NQEs. The Stokes-Einstein relation, Wiedemann-Franz law, and isotope effects are re-examined, showing different behaviors in nuclear quantum dynamics. PMID:24968754

  12. Quantum Linear System Algorithm for Dense Matrices.

    PubMed

    Wossnig, Leonard; Zhao, Zhikuan; Prakash, Anupam

    2018-02-02

    Solving linear systems of equations is a frequently encountered problem in machine learning and optimization. Given a matrix A and a vector b the task is to find the vector x such that Ax=b. We describe a quantum algorithm that achieves a sparsity-independent runtime scaling of O(κ^{2}sqrt[n]polylog(n)/ε) for an n×n dimensional A with bounded spectral norm, where κ denotes the condition number of A, and ε is the desired precision parameter. This amounts to a polynomial improvement over known quantum linear system algorithms when applied to dense matrices, and poses a new state of the art for solving dense linear systems on a quantum computer. Furthermore, an exponential improvement is achievable if the rank of A is polylogarithmic in the matrix dimension. Our algorithm is built upon a singular value estimation subroutine, which makes use of a memory architecture that allows for efficient preparation of quantum states that correspond to the rows of A and the vector of Euclidean norms of the rows of A.

  13. Quantum Linear System Algorithm for Dense Matrices

    NASA Astrophysics Data System (ADS)

    Wossnig, Leonard; Zhao, Zhikuan; Prakash, Anupam

    2018-02-01

    Solving linear systems of equations is a frequently encountered problem in machine learning and optimization. Given a matrix A and a vector b the task is to find the vector x such that A x =b . We describe a quantum algorithm that achieves a sparsity-independent runtime scaling of O (κ2√{n }polylog(n )/ɛ ) for an n ×n dimensional A with bounded spectral norm, where κ denotes the condition number of A , and ɛ is the desired precision parameter. This amounts to a polynomial improvement over known quantum linear system algorithms when applied to dense matrices, and poses a new state of the art for solving dense linear systems on a quantum computer. Furthermore, an exponential improvement is achievable if the rank of A is polylogarithmic in the matrix dimension. Our algorithm is built upon a singular value estimation subroutine, which makes use of a memory architecture that allows for efficient preparation of quantum states that correspond to the rows of A and the vector of Euclidean norms of the rows of A .

  14. What Cues Do Ungulates Use to Assess Predation Risk in Dense Temperate Forests?

    PubMed Central

    Kuijper, Dries P. J.; Verwijmeren, Mart; Churski, Marcin; Zbyryt, Adam; Schmidt, Krzysztof; Jędrzejewska, Bogumiła; Smit, Chris

    2014-01-01

    Anti-predator responses by ungulates can be based on habitat features or on the near-imminent threat of predators. In dense forest, cues that ungulates use to assess predation risk likely differ from half-open landscapes, as scent relative to sight is predicted to be more important. We studied, in the Białowieża Primeval Forest (Poland), whether perceived predation risk in red deer (Cervus elaphus) and wild boar (Sus scrofa) is related to habitat visibility or olfactory cues of a predator. We used camera traps in two different set-ups to record undisturbed ungulate behavior and fresh wolf (Canis lupus) scats as olfactory cue. Habitat visibility at fixed locations in deciduous old growth forest affected neither vigilance levels nor visitation rate and cumulative visitation time of both ungulate species. However, red deer showed a more than two-fold increase of vigilance level from 22% of the time present on control plots to 46% on experimental plots containing one wolf scat. Higher vigilance came at the expense of time spent foraging, which decreased from 32% to 12% while exposed to the wolf scat. These behavioral changes were most pronounced during the first week of the experiment but continuous monitoring of the plots suggested that they might last for several weeks. Wild boar did not show behavioral responses indicating higher perceived predation risk. Visitation rate and cumulative visitation time were not affected by the presence of a wolf scat in both ungulate species. The current study showed that perceived predation risk in red deer and wild boar is not related to habitat visibility in a dense forest ecosystem. However, olfactory cues of wolves affected foraging behavior of their preferred prey species red deer. We showed that odor of wolves in an ecologically equivalent dose is sufficient to create fine-scale risk factors for red deer. PMID:24404177

  15. Testing of a new dense gas approach in the Lagrangian Dispersion Model SPRAY.

    NASA Astrophysics Data System (ADS)

    Mortarini, Luca; Alessandrini, Stefano; Ferrero, Enrico; Anfossi, Domenico; Manfrin, Massimiliano

    2013-04-01

    A new original method for the dispersion of a positively and negatively buoyant plume is proposed. The buoyant pollutant movement is treated introducing a fictitious scalar inside the Lagrangian Stochastic Particle Model SPRAY. The method is based on the same idea of Alessandrini and Ferrero (Phys. A 388:1375-1387, 2009) for the treatment of a background substance entrainment into the plume. In this application, the fictitious scalar is the density and momentum difference between the plume portions and the environment air that naturally takes into account the interaction between the plume and the environment. As a consequence, no more particles than those inside the plume have to be released to simulate the entrainment of the background air temperature. In this way the entrainment is properly simulated and the plume sink is calculated from the local property of the flow. This new approach is wholly Lagrangian in the sense that the Eulerian grid is only used to compute the propriety of a portion of the plume from the particles contained in every cell. No equation of the bulk plume is solved on a fixed grid. To thoroughly test the turbulent velocity field calculated by the model, the latter is compared with a water tank experiment carried out in the TURLAB laboratory in Turin (Italy). A vertical density driven current was created releasing a saline solution (salt and water) in a water tank with no mean flow. The experiment reproduces in physical similarity, based on the density Froud number, the release of a dense gas in the planetary boundary layer and the Particle Image Velocimetry technique has been used to analyze the buoyancy generated velocity field. The high temporal and spatial resolution of the measurements gives a deep insight to the problems of the bouncing of the dense gas and of the creation of the outflow velocity at the ground.

  16. NY-uHMT: A dense hydro-meteorological network to characterize urban land-atmosphere interactions

    NASA Astrophysics Data System (ADS)

    Ramamurthy, P.; Lakhankar, T.; Khanbilvardi, R.; Devineni, N.

    2016-12-01

    Most people in the US live in large Metropolitan areas that have a dense urban core in the center, dominated by built surfaces and surrounded by residential/suburban areas that consist a mix of built, vegetated and permeable surfaces. This creates a gradient in the hydro-meteorological environment giving rise to complex land-atmosphere interactions. Current modeling platforms and observational techniques like tower measurements do not adequately account for the underlying heterogeneity. To address this critical gap in our understanding we have instituted a dense network of sensors in the New York Metropolitan area. This unique urban sensor network consists of instrumentation to monitor soil moisture at multiple depths along with air temperature, relative humidity and precipitation, with room to add additional sensors in the future. The network is autonomous and connected to a centralized server using cellular towers. Apart from describing the spatial variability in hydro-meteorological quantities the network will also aid in conducting high-resolution numerical simulations to study and forecast urban weather and climate. In one such simulation conducted to partition the influence of storage flux, wind pattern and circulation and soil moisture deficit on urban heat island intensity (UHI), we found that the daily variability in UHI in NYC was sensitive to available energy and wind pattern. The long-term trend in UHI was however related to soil moisture deficit. In fact a prolonged heat wave period witnessed during summer 2006 correlated well with an extended dry period and the daily UHI in NYC almost doubled. Moreover, the urban soils also suffered from high degree of dessication, owing to drier urban boundary layer.

  17. Non-thermal production of minimal dark matter via right-handed neutrino decay

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Aoki, Mayumi; Toma, Takashi; Vicente, Avelino

    2015-09-29

    Minimal Dark Matter (MDM) stands as one of the simplest dark matter scenarios. In MDM models, annihilation and co-annihilation processes among the members of the MDM multiplet are usually very efficient, pushing the dark matter mass above O(10) TeV in order to reproduce the observed dark matter relic density. Motivated by this little drawback, in this paper we consider an extension of the MDM scenario by three right-handed neutrinos. Two specific choices for the MDM multiplet are studied: a fermionic SU(2){sub L} quintuplet and a scalar SU(2){sub L} septuplet. The lightest right-handed neutrino, with tiny Yukawa couplings, never reaches thermalmore » equilibrium in the early universe and is produced by freeze-in. This creates a link between dark matter and neutrino physics: dark matter can be non-thermally produced by the decay of the lightest right-handed neutrino after freeze-out, allowing to lower significantly the dark matter mass. We discuss the phenomenology of the non-thermally produced MDM and, taking into account significant Sommerfeld corrections, we find that the dark matter mass must have some specific values in order not to be in conflict with the current bounds from gamma-ray observations.« less

  18. Non-thermal production of minimal dark matter via right-handed neutrino decay

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Aoki, Mayumi; Toma, Takashi; Vicente, Avelino, E-mail: mayumi@hep.s.kanazawa-u.ac.jp, E-mail: takashi.toma@th.u-psud.fr, E-mail: Avelino.Vicente@ulg.ac.be

    2015-09-01

    Minimal Dark Matter (MDM) stands as one of the simplest dark matter scenarios. In MDM models, annihilation and co-annihilation processes among the members of the MDM multiplet are usually very efficient, pushing the dark matter mass above O(10) TeV in order to reproduce the observed dark matter relic density. Motivated by this little drawback, in this paper we consider an extension of the MDM scenario by three right-handed neutrinos. Two specific choices for the MDM multiplet are studied: a fermionic SU(2){sub L} quintuplet and a scalar SU(2){sub L} septuplet. The lightest right-handed neutrino, with tiny Yukawa couplings, never reaches thermalmore » equilibrium in the early universe and is produced by freeze-in. This creates a link between dark matter and neutrino physics: dark matter can be non-thermally produced by the decay of the lightest right-handed neutrino after freeze-out, allowing to lower significantly the dark matter mass. We discuss the phenomenology of the non-thermally produced MDM and, taking into account significant Sommerfeld corrections, we find that the dark matter mass must have some specific values in order not to be in conflict with the current bounds from gamma-ray observations.« less

  19. Phase transitions in core-collapse supernova matter at sub-saturation densities

    NASA Astrophysics Data System (ADS)

    Pais, Helena; Newton, William G.; Stone, Jirina R.

    2014-12-01

    Phase transitions in hot, dense matter in the collapsing cores of massive stars have an important impact on the core-collapse supernova mechanism as they absorb heat, disrupt homology, and so weaken the developing shock. We perform a three-dimensional, finite temperature Skyrme-Hartree-Fock (SHF) study of inhomogeneous nuclear matter to determine the critical density and temperature for the phase transition between the pasta phase and homogeneous matter and its properties. We employ four different parametrizations of the Skyrme nuclear energy-density functional, SkM*, SLy4, NRAPR, and SQMC700, which span a range of saturation-density symmetry energy behaviors constrained by a variety of nuclear experimental probes. For each of these interactions we calculate free energy, pressure, entropy, and chemical potentials in the range of particle number densities where the nuclear pasta phases are expected to exist, 0.02-0.12 fm-3, temperatures 2-8 MeV, and a proton fraction of 0.3. We find unambiguous evidence for a first-order phase transition to uniform matter, unsoftened by the presence of the pasta phases. No conclusive signs of a first-order phase transition between the pasta phases is observed, and it is argued that the thermodynamic quantities vary continuously right up to the first-order phase transition to uniform matter. We compare our results with thermodynamic spinodals calculated using the same Skyrme parametrizations, finding that the effect of short-range Coulomb correlations and quantum shell effects included in our model leads to the pasta phases existing at densities up to 0.01 fm-3 above the spinodal boundaries, thus increasing the transition density to uniform matter by the same amount. The transition density is otherwise shown to be insensitive to the symmetry energy at saturation density within the range constrained by the concordance of a variety of experimental constraints, and can be taken to be a well determined quantity.

  20. Uncountably many maximizing measures for a dense subset of continuous functions

    NASA Astrophysics Data System (ADS)

    Shinoda, Mao

    2018-05-01

    Ergodic optimization aims to single out dynamically invariant Borel probability measures which maximize the integral of a given ‘performance’ function. For a continuous self-map of a compact metric space and a dense set of continuous functions, we show the existence of uncountably many ergodic maximizing measures. We also show that, for a topologically mixing subshift of finite type and a dense set of continuous functions there exist uncountably many ergodic maximizing measures with full support and positive entropy.