Sample records for dynamics md density

  1. Microscopic dynamical description of proton-induced fission with the Constrained Molecular Dynamics (CoMD) Model

    E-Print Network [OSTI]

    N. Vonta; G. A. Souliotis; M. Veselsky; A. Bonasera

    2015-06-16T23:59:59.000Z

    The microscopic description of nuclear fission still remains a topic of intense basic research. Un- derstanding nuclear fission, apart from a theoretical point of view, is of practical importance for energy production and the transmutation of nuclear waste. In nuclear astrophysics, fission sets the upper limit to the nucleosynthesis of heavy elements via the r-process. In this work we initiated a systematic study of intermediate energy proton-induced fission using the Constrained Molecu- lar Dynamics (CoMD) code. The CoMD code implements an effective interaction with a nuclear matter compressibility of K=200 (soft EOS) with several forms of the density dependence of the nucleon-nucleon symmetry potential. Moreover, a constraint is imposed in the phase-space occu- pation for each nucleon restoring the Pauli principle at each time step of the collision. A proper choice of the surface parameter of the effective interaction has been made to describe fission. In this work, we present results of fission calculations for proton-induced reactions on : a) 232 Th at 27 and 63 MeV, b) 235 U at 10, 30, 60 and 100 MeV, and c) 238 U at 100 and 660 MeV. The calculated observables include fission-fragment mass distributions, total fission energies, neutron multiplicities and fission times. These observables are compared to available experimental data. We show that the microscopic CoMD code is able to describe the complicated many-body dynamics of the fission process at intermediate and high energy and give a reasonable estimate of the fission time scale. Sensitivity of the results to the density dependence of the nucleon symmetry potential (and, thus, the nuclear symmetry energy) is found. Further improvements of the code are necessary to achieve a satisfactory description of low energy fission in which shell effects play a dominant role.

  2. Path Integral Monte Carlo and Density Functional Molecular Dynamics Simulations of Hot, Dense Helium

    E-Print Network [OSTI]

    Militzer, Burkhard

    Path Integral Monte Carlo and Density Functional Molecular Dynamics Simulations of Hot, Dense integral Monte Carlo (PIMC) and density func- tional molecular dynamics (DFT-MD), are applied to study hot excitation mecha- nisms that determine their behavior at high temperature. The helium atom has two ionization

  3. PuReMD-GPU: A reactive molecular dynamics simulation package for GPUs

    SciTech Connect (OSTI)

    Kylasa, S.B., E-mail: skylasa@purdue.edu [Department of Elec. and Comp. Eng., Purdue University, West Lafayette, IN 47907 (United States); Aktulga, H.M., E-mail: hmaktulga@lbl.gov [Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, MS 50F-1650, Berkeley, CA 94720 (United States); Grama, A.Y., E-mail: ayg@cs.purdue.edu [Department of Computer Science, Purdue University, West Lafayette, IN 47907 (United States)

    2014-09-01T23:59:59.000Z

    We present an efficient and highly accurate GP-GPU implementation of our community code, PuReMD, for reactive molecular dynamics simulations using the ReaxFF force field. PuReMD and its incorporation into LAMMPS (Reax/C) is used by a large number of research groups worldwide for simulating diverse systems ranging from biomembranes to explosives (RDX) at atomistic level of detail. The sub-femtosecond time-steps associated with ReaxFF strongly motivate significant improvements to per-timestep simulation time through effective use of GPUs. This paper presents, in detail, the design and implementation of PuReMD-GPU, which enables ReaxFF simulations on GPUs, as well as various performance optimization techniques we developed to obtain high performance on state-of-the-art hardware. Comprehensive experiments on model systems (bulk water and amorphous silica) are presented to quantify the performance improvements achieved by PuReMD-GPU and to verify its accuracy. In particular, our experiments show up to 16× improvement in runtime compared to our highly optimized CPU-only single-core ReaxFF implementation. PuReMD-GPU is a unique production code, and is currently available on request from the authors.

  4. Fast plane wave density functional theory molecular dynamics calculations on multi-GPU machines

    SciTech Connect (OSTI)

    Jia, Weile, E-mail: jiawl@sccas.cn [Supercomputing Center, Computer Network Information Center, Chinese Academy of Sciences, No. 4 South 4th Street, ZhongGuanCun, Beijing 100190 (China) [Supercomputing Center, Computer Network Information Center, Chinese Academy of Sciences, No. 4 South 4th Street, ZhongGuanCun, Beijing 100190 (China); University of Chinese Academy of Sciences, Beijing (China); Fu, Jiyun, E-mail: fujy@sccas.cn [Supercomputing Center, Computer Network Information Center, Chinese Academy of Sciences, No. 4 South 4th Street, ZhongGuanCun, Beijing 100190 (China) [Supercomputing Center, Computer Network Information Center, Chinese Academy of Sciences, No. 4 South 4th Street, ZhongGuanCun, Beijing 100190 (China); University of Chinese Academy of Sciences, Beijing (China); Cao, Zongyan, E-mail: zycao@sccas.cn [Supercomputing Center, Computer Network Information Center, Chinese Academy of Sciences, No. 4 South 4th Street, ZhongGuanCun, Beijing 100190 (China)] [Supercomputing Center, Computer Network Information Center, Chinese Academy of Sciences, No. 4 South 4th Street, ZhongGuanCun, Beijing 100190 (China); Wang, Long, E-mail: wangl@sccas.cn [Supercomputing Center, Computer Network Information Center, Chinese Academy of Sciences, No. 4 South 4th Street, ZhongGuanCun, Beijing 100190 (China)] [Supercomputing Center, Computer Network Information Center, Chinese Academy of Sciences, No. 4 South 4th Street, ZhongGuanCun, Beijing 100190 (China); Chi, Xuebin, E-mail: chi@sccas.cn [Supercomputing Center, Computer Network Information Center, Chinese Academy of Sciences, No. 4 South 4th Street, ZhongGuanCun, Beijing 100190 (China)] [Supercomputing Center, Computer Network Information Center, Chinese Academy of Sciences, No. 4 South 4th Street, ZhongGuanCun, Beijing 100190 (China); Gao, Weiguo, E-mail: wggao@fudan.edu.cn [School of Mathematical Sciences, Fudan University, 220 Handan Road, Shanghai 200433 (China) [School of Mathematical Sciences, Fudan University, 220 Handan Road, Shanghai 200433 (China); MOE Key Laboratory of Computational Physical Sciences, Fudan University, Shanghai (China); Wang, Lin-Wang, E-mail: lwwang@lbl.gov [Material Science Division, Lawrence Berkeley National Laboratory, One Cyclotron Road Mail Stop 50F Berkeley, CA 94720 (United States)] [Material Science Division, Lawrence Berkeley National Laboratory, One Cyclotron Road Mail Stop 50F Berkeley, CA 94720 (United States)

    2013-10-15T23:59:59.000Z

    Plane wave pseudopotential (PWP) density functional theory (DFT) calculation is the most widely used method for material simulations, but its absolute speed stagnated due to the inability to use large scale CPU based computers. By a drastic redesign of the algorithm, and moving all the major computation parts into GPU, we have reached a speed of 12 s per molecular dynamics (MD) step for a 512 atom system using 256 GPU cards. This is about 20 times faster than the CPU version of the code regardless of the number of CPU cores used. Our tests and analysis on different GPU platforms and configurations shed lights on the optimal GPU deployments for PWP-DFT calculations. An 1800 step MD simulation is used to study the liquid phase properties of GaInP.

  5. Dynamics of a globular protein and its hydration water studied by neutron scattering and MD simulations

    E-Print Network [OSTI]

    Chen, Sow-Hsin

    2010-01-01T23:59:59.000Z

    This review article describes our neutron scattering experiments made in the past four years for the understanding of the single-particle (hydrogen atom) dynamics of a protein and its hydration water and the strong coupling ...

  6. Dynamic Evolution for Risk-Neutral Densities

    E-Print Network [OSTI]

    2008-10-27T23:59:59.000Z

    specifications of the data are as follows: the spot asset price is 590, the risk- free interest rate is ... than 10) the recovered risk-neutral densities exhibit less smoothness than in the cases .... Technical report, Purdue University, 1995. [31] A. M. ...

  7. Effects of confinement on water structure and dynamics and on proton transport: a molecular simulation study 

    E-Print Network [OSTI]

    Hirunsit, Pussana

    2009-05-15T23:59:59.000Z

    Classical molecular dynamics (MD) simulations are performed to study structural and dynamic properties of water confined within graphite surfaces. The surfaces are separated at distances varying between 7 and 14.5 Å and the water density is held...

  8. Harvesting graphics power for MD simulations

    E-Print Network [OSTI]

    J. A. van Meel; A. Arnold; D. Frenkel; S. F. Portegies Zwart; R. G. Belleman

    2007-09-20T23:59:59.000Z

    We discuss an implementation of molecular dynamics (MD) simulations on a graphic processing unit (GPU) in the NVIDIA CUDA language. We tested our code on a modern GPU, the NVIDIA GeForce 8800 GTX. Results for two MD algorithms suitable for short-ranged and long-ranged interactions, and a congruential shift random number generator are presented. The performance of the GPU's is compared to their main processor counterpart. We achieve speedups of up to 80, 40 and 150 fold, respectively. With newest generation of GPU's one can run standard MD simulations at 10^7 flops/$.

  9. MD user's manual

    SciTech Connect (OSTI)

    Correll, S.

    1988-04-01T23:59:59.000Z

    MD is the S-1 Mark IIA machine debugger. It is the hardware equivalent of a software symbolic debugger. It consists of a user-level program which executes on a VAX computer running Berkeley UNIX and a device driver which resides within the UNIX kernel. It communicates with the S-1 Mark IIA through a front-end interface attached to the UNIBUS of the VAX. The first section of this report describes MD's user interface and command set. The second section describes the virtual machine interface through which MD and the UNIX device driver communicate.

  10. Dynamics of disentanglement, density matrix, and coherence in neutrino oscillations

    SciTech Connect (OSTI)

    Wu Jun; Boyanovsky, Daniel [Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States); Hutasoit, Jimmy A.; Holman, Richard [Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States)

    2010-07-01T23:59:59.000Z

    In charged current weak interaction processes, neutrinos are produced in an entangled state with the charged lepton. This correlated state is disentangled by the measurement of the charged lepton in a detector at the production site. We study the dynamical aspects of disentanglement, propagation, and detection, in particular, the conditions under which the disentangled state is a coherent superposition of mass eigenstates. The appearance and disappearance far-detection processes are described from the time evolution of this disentangled 'collapsed' state. The familiar quantum mechanical interpretation and factorization of the detection rate emerges when the quantum state is disentangled on time scales much shorter than the inverse oscillation frequency, in which case the final detection rate factorizes in terms of the usual quantum mechanical transition probability provided the final density of states is insensitive to the neutrino energy difference. We suggest possible corrections for short-baseline experiments. If the charged lepton is unobserved, neutrino oscillations and coherence are described in terms of a reduced density matrix obtained by tracing out an unobserved charged lepton. The diagonal elements in the mass basis describe the production of mass eigenstates whereas the off-diagonal ones provide a measure of coherence. It is shown that coherences are of the same order of the diagonal terms on time scales up to the inverse oscillation frequency, beyond which the coherences oscillate as a result of the interference between mass eigenstates.

  11. Why are MD simulated protein folding times wrong? Dmitry Nerukh

    E-Print Network [OSTI]

    Nerukh, Dmitry

    Why are MD simulated protein folding times wrong? Dmitry Nerukh Unilever Centre for Molecular.ac.uk The question of significant deviations of protein folding times simulated using molecular dynamics from

  12. SciTech Connect: Chiral dynamics and peripheral transverse densities

    Office of Scientific and Technical Information (OSTI)

    in terms of frame-independent charge and magnetization densities in transverse space. This formulation allows one to identify the chiral components of nucleon structure as...

  13. applying dynamic flow-density: Topics by E-print Network

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

    20 21 22 23 24 25 Next Page Last Page Topic Index 1 Online traffic flow model applying dynamic flow-density relation CERN Preprints Summary: This dissertation describes a new...

  14. Light-front representation of chiral dynamics in peripheral transverse densities

    E-Print Network [OSTI]

    Granados, C

    2015-01-01T23:59:59.000Z

    The nucleon's electromagnetic form factors are expressed in terms of the transverse densities of charge and magnetization at fixed light-front time. At peripheral transverse distances $b = O(M_\\pi^{-1})$ the densities are governed by chiral dynamics and can be calculated model-independently using chiral effective field theory (EFT). We represent the leading-order chiral EFT results for the peripheral transverse densities as overlap integrals of chiral light-front wave functions, describing the transition of the initial nucleon to soft pion-nucleon intermediate states and back. The new representation (a) explains the parametric order of the peripheral transverse densities; (b) establishes an inequality between the spin-independent and -dependent densities; (c) exposes the role of pion orbital angular momentum in chiral dynamics; (d) reveals a large left-right asymmetry of the current in a transversely polarized nucleon and suggests a simple interpretation. The light-front representation enables a first-quantiz...

  15. Momentum density of spacetime and the gravitational dynamics

    E-Print Network [OSTI]

    T. Padmanabhan

    2015-06-11T23:59:59.000Z

    I introduce a covariant four-vector $\\mathcal{G}^a[v]$, which can be interpreted as the momentum density attributed to the spacetime geometry by an observer with velocity $v^a$, and describe its properties: (a) Demanding that the total momentum of matter plus geometry is conserved for all observers, leads to the gravitational field equations. Thus, how matter curves spacetime is entirely determined by this principle of momentum conservation. (b) The $\\mathcal{G}^a[v]$ can be related to the gravitational Lagrangian in a manner similar to the usual definition of Hamiltonian in, say, classical mechanics. (c) Geodesic observers in a spacetime will find that the conserved total momentum vanishes on-shell. (d) The on-shell, conserved, total energy in a region of space, as measured by the comoving observers, will be equal to the total heat energy of the boundary surface. (e) The off-shell gravitational energy in a region will be the sum of the ADM energy in the bulk plus the thermal energy of the boundary. These results suggest that $\\mathcal{G}^a[v]$ can be a useful physical quantity to probe the gravitational theories.

  16. Momentum density of spacetime and the gravitational dynamics

    E-Print Network [OSTI]

    Padmanabhan, T

    2015-01-01T23:59:59.000Z

    I introduce a covariant four-vector $\\mathcal{G}^a[v]$, which can be interpreted as the momentum density attributed to the spacetime geometry by an observer with velocity $v^a$, and describe its properties: (a) Demanding that the total momentum of matter plus geometry is conserved for all observers, leads to the gravitational field equations. Thus, how matter curves spacetime is entirely determined by this principle of momentum conservation. (b) The $\\mathcal{G}^a[v]$ can be related to the gravitational Lagrangian in a manner similar to the usual definition of Hamiltonian in, say, classical mechanics. (c) Geodesic observers in a spacetime will find that the conserved total momentum vanishes on-shell. (d) The on-shell, conserved, total energy in a region of space, as measured by the comoving observers, will be equal to the total heat energy of the boundary surface. (e) The off-shell gravitational energy in a region will be the sum of the ADM energy in the bulk plus the thermal energy of the boundary. These res...

  17. Susan P. Taylor, MD Shorewood, Wisconsin

    E-Print Network [OSTI]

    Noxapater, Mississippi Corey W. Gilliland, MD Mesa, Arizona Jeanne V. Hamel, MD Elk Grove, California Steven Manhattan, Kansas Dean Afif Shoucair, DO Frankfort, Illinois John Mitchell Simson, MD Albuquerque, New

  18. Distributed delay model for density wave dynamics in gas lifted wells Laure Sin`egre, Nicolas Petit

    E-Print Network [OSTI]

    Distributed delay model for density wave dynamics in gas lifted wells Laure Sin`egre, Nicolas Petit in the tubing D. dynamical choking is used to stabilise the density wave instability. In this paper, we propose instabilities cause production losses. One of these instabilities, referred to as the "density-wave

  19. Dynamical friction in constant density cores: a failure of the Chandrasekhar formula

    E-Print Network [OSTI]

    J. I. Read; Tobias Goerdt; Ben Moore; A. P. Pontzen; Joachim Stadel; George Lake

    2006-10-04T23:59:59.000Z

    Using analytic calculations and N-body simulations we show that in constant density (harmonic) cores, sinking satellites undergo an initial phase of very rapid (super-Chandrasekhar) dynamical friction, after which they experience no dynamical friction at all. For density profiles with a central power law profile of log-slope, $-\\alpha$, the infalling satellite heats the background and causes $\\alpha$ to decrease. For $\\alpha < 0.5$ initially, the satellite generates a small central constant density core and stalls as in the $\\alpha = 0$ case. We discuss some astrophysical applications of our results to decaying satellite orbits, galactic bars and mergers of supermassive black hole binaries. In a companion paper we show that a central constant density core can provide a natural solution to the timing problem for Fornax's globular clusters.

  20. Water dynamics: Relation between hydrogen bond bifurcations, molecular jumps, local density & hydrophobicity

    E-Print Network [OSTI]

    John Tatini Titantah; Mikko Karttunen

    2013-03-29T23:59:59.000Z

    Structure and dynamics of water remain a challenge. Resolving the properties of hydrogen bonding lies at the heart of this puzzle. Here we employ ab initio Molecular Dynamics (AIMD) simulations over a wide temperature range. The total simulation time was approx 2 ns. Both bulk water and water in the presence of a small hydrophobic molecule were simulated. We show that large-angle jumps and bond bifurcations are fundamental properties of water dynamics and that they are intimately coupled to both local density and hydrogen bond stretch oscillations in scales from about 60 to a few hundred femtoseconds: Local density differences are the driving force for bond bifurcations and the consequent large-angle jumps. The jumps are intimately connected to the recently predicted energy asymmetry. Our analysis also appears to confirm the existence of the so-called negativity track provided by the lone pairs of electrons on the oxygen atom to enable water rotation.

  1. Liquids that form due to dynamics of the molecules that depend on the local density

    E-Print Network [OSTI]

    Richard P. Sear

    2015-03-26T23:59:59.000Z

    RNA molecules in living cells form what look like liquid droplets formed by liquid/liquid phase separation. But unlike the molecules in conventional phase separating mixtures, RNA molecules are transported by molecular motors that consume energy and so are out of equilibrium. Motivated by this we consider what sort of simple rules for the dynamics of model mRNA molecules lead to liquid/liquid phase separation. We find that dynamics that slow as the local density of molecules increases, drive the formation of liquids. We also look at the analogous separation of the two blocks of a block copolymer, in which the monomers of one block have dynamics that depend on the local density of monomers of that block. We find that this block condenses and separates from the monomers of the other block. This is a simple model of the out-of-equilibrium domain formation found in the chromatin in the nucleus of cells.

  2. Where to find the mind: Identifying the scale of cognitive dynamics Luke Conlin, Department of Curriculum & Instruction,Benjamin Building, College Park, MD 20742 USA,

    E-Print Network [OSTI]

    Hammer, David

    Where to find the mind: Identifying the scale of cognitive dynamics Luke Conlin, Department as occurring within individual minds and those that treat it as irreducibly distributed or situated in material and social contexts. We contend that accounts of individual minds as complex systems are theoretically

  3. Two-flavor condensates in chiral dynamics: temperature and isospin density effects

    E-Print Network [OSTI]

    M. Loewe; C. Villavicencio

    2005-05-17T23:59:59.000Z

    Isospin density and thermal corrections for several condensates are discussed, at the one-loop level, in the frame of chiral dynamics with pionic degrees of freedom. The evolution of such objects give an additional insight into the condensed-pion phase transition, that occurs basically when $|\\mui|>m_\\pi$, being $|\\mui|$ the isospin chemical potential. Calculations are done in both phases, showing a good agreement with lattice results for such condensates.

  4. Dynamic density functional theory of protein adsorption on polymer-coated nanoparticles

    E-Print Network [OSTI]

    Angioletti-Uberti, Stefano; Dzubiella, Joachim

    2014-01-01T23:59:59.000Z

    We present a theoretical model for the description of the adsorption kinetics of globular proteins onto charged core-shell microgel particles based on Dynamic Density Functional Theory (DDFT). This model builds on a previous description of protein adsorption thermodynamics [Yigit \\textit{et al}, Langmuir 28 (2012)], shown to well interpret the available calorimetric experimental data of binding isotherms. In practice, a spatially-dependent free-energy functional including the same physical interactions is built, and used to study the kinetics via a generalised diffusion equation. To test this model, we apply it to the case study of Lysozyme adsorption on PNIPAM coated nanoparticles, and show that the dynamics obtained within DDFT is consistent with that extrapolated from experiments. We also perform a systematic study of the effect of various parameters in our model, and investigate the loading dynamics as a function of proteins' valence and hydrophobic adsorption energy, as well as their concentration and th...

  5. Dynamic density field measurements of an explosively driven ????? phase transition in iron

    SciTech Connect (OSTI)

    Hull, L. M.; Gray, G. T.; Warthen, B. J. [Los Alamos National Laboratory, Los Alamos, New Mexico 87544 (United States)

    2014-07-28T23:59:59.000Z

    We provide a unique set of observations of the behavior of the ??? phase transition under a complex axially symmetric loading path created by sweeping a detonation wave along the end surface of a cylindrical sample. The primary data sets are the measured mass density distributions acquired at 5 independent times during the sweep of the detonation along the surface. Shocked regions and boundaries are measured, as well as regions and boundaries of elevated density (presumed to be the ??phase iron). The formation and dynamics of these regions were captured and are available for comparisons to material descriptions. We also applied 16 Photon Doppler Velocimetry probes to capture the free surface velocity along a discrete set of radially distributed points in order to compare and correlate the density measurements with previous shock wave studies. The velocimetry data are in nearly exact agreement with previous shock wave studies of the ??? phase transition, the density distributions, while generally in agreement with expectations evolved from the shock wave studies, show that the epsilon phase is generated in regions of high shear stress but at hydrostatic stresses below the typically quoted 13?GPa value. The density field measurements are particularly useful for observing the effects of the forward and reverse transformation kinetics, as well as the reverse transformation hysteresis.

  6. Steve Nelson, MD Backes, PhD

    E-Print Network [OSTI]

    Dean Steve Nelson, MD Associate Dean for Research Wayne Backes, PhD Associate Dean for Fiscal Gregory, PhD Assistant Dean of VA Affairs Paul Rosenfeld, MD Basic Science Department Heads (6) Clinical, MD Director of Basic Sciences Curriculum Michael Levitzky, PhD Assistant Dean at Children's Hospital

  7. Dynamical and sequential decay effects on isoscaling and density dependence of the symmetry energy

    E-Print Network [OSTI]

    W. D. Tian; Y. G. Ma; X. Z. Cai; D. Q. Fang; W. Guo; C. W. Ma; G. H. Liu; W. Q. Shen; Y. Shi; H. W. Wang; K. Wang; W. Xu; T. Z. Yan

    2006-01-25T23:59:59.000Z

    The isoscaling properties of the primary and final products are studied via isospin dependent quantum molecular dynamics (IQMD) model and the followed sequential decay model GEMINI, respectively. It is found that the isoscaling parameters $\\alpha$ of both primary and final products keep no significant change for light fragments, but increases with the mass for intermediate and heavy products. The dynamical effects on isoscaling are exhibited by that $\\alpha$ value decreases a little with the evolution time of the system, and opposite trend for the heavy products. The secondary decay effects on isoscaling are reflected in the increasing of the $\\alpha$ value for the final products which experiences secondary decay process. Furthermore the density dependence of the symmetry energy has also been explored, it is observed that in the low densities the symmetry energy coefficient has the form of $C_{sym}(\\rho)\\sim C_{0}(\\rho/\\rho_{0})^{\\gamma}$, where $\\gamma = 0.7 \\sim 1.3$ for both primary and final products, but $C_{0}$ have different values for primary and final products. It is also suggested that it might be more reasonable to describe the density dependence of the symmetry energy coefficient by the $C_{sym}(\\rho/\\rho_{0})\\approx C_{1}(\\rho/\\rho_{0})^{\\gamma_{soft}} + C_{2}(\\rho/\\rho_{0})^{\\gamma_{stiff}}$ with $\\gamma_{soft}\\leq 1$, $\\gamma_{stiff}\\geq 1$ and $C_{1}, C_{2}$ constant parameters.

  8. Envelope density pattern around wide binary AGB stars: a dynamical model

    E-Print Network [OSTI]

    J. H. He

    2007-03-26T23:59:59.000Z

    The goal is to build up a simple dynamical model for the out-flowing circumstellar envelope around AGB stars in a wide binary system to explore the parameter dependence of the geometrical characteristics of column density patterns. An AGB star in a wide binary system is considered as a 3-D piston model that can induce a 3-D quasi-spherical density structure in the circumstellar envelope by orbital motion of the AGB star. The column density pattern only depends on two parameters: eccentricity of the orbit e and the terminal outflow velocity to mean orbital velocity ratio gamma. When viewed perpendicular to the orbital plane, spiral, broken spiral, and incomplete concentric shell patterns can be seen, while when viewed along the orbital plane, alternative concentric half-shell, egg-shell, and half-shell half-gap patterns will develop. Non-zero eccentricity causes asymmetry, while larger gamma makes a weaker pattern and helps bring out asymmetry. A spiral pattern may becomes broken when e > 0.4. The spiral center is always less than 12% of spiral pitch away from the orbit center. One should have more chances (~ 80%) seeing spiral-like patterns than seeing concentric shells (~ 20%) in the circumstellar envelope of wide binary AGB stars.

  9. Abington Abington Pediatrics* 360 Brockton Avenue, Suite 102, MA 02351 Yara Fernandez, MD 781-792-1999 781-792-1990 Laurie Massey, MD

    E-Print Network [OSTI]

    Mootha, Vamsi K.

    Andrea Reilly, MD Milton Pediatric Associates - MGH 10 Hawthorne Place, Suite 110, MA 02114 JonathanCullough, MD Rebecca Niloff, MD Cara O'Reilly, MD Scott Paul, MD Jonathon Brenner, MD John Robinson, MD Heidi-643-8120 Elizabeth Turnock, MD Pediatric Group Practice 55 Fruit Street, YAW 6D, MA 02114 Ronald Benz, MD 617

  10. Dynamic density functional theory of protein adsorption on polymer-coated nanoparticles

    E-Print Network [OSTI]

    Stefano Angioletti-Uberti; Matthias Ballauff; Joachim Dzubiella

    2014-07-30T23:59:59.000Z

    We present a theoretical model for the description of the adsorption kinetics of globular proteins onto charged core-shell microgel particles based on Dynamic Density Functional Theory (DDFT). This model builds on a previous description of protein adsorption thermodynamics [Yigit \\textit{et al}, Langmuir 28 (2012)], shown to well interpret the available calorimetric experimental data of binding isotherms. In practice, a spatially-dependent free-energy functional including the same physical interactions is built, and used to study the kinetics via a generalised diffusion equation. To test this model, we apply it to the case study of Lysozyme adsorption on PNIPAM coated nanoparticles, and show that the dynamics obtained within DDFT is consistent with that extrapolated from experiments. We also perform a systematic study of the effect of various parameters in our model, and investigate the loading dynamics as a function of proteins' valence and hydrophobic adsorption energy, as well as their concentration and that of the nanoparticles. Although we concentrated here on the case of adsorption for a single protein type, the model's generality allows to study multi-component system, providing a reliable instrument for future studies of competitive and cooperative adsorption effects often encountered in protein adsorption experiments.

  11. Quadrupole collective dynamics from energy density functionals: Collective Hamiltonian and the interacting boson model

    SciTech Connect (OSTI)

    Nomura, K.; Vretenar, D. [Department of Physics, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Physics Department, Faculty of Science, University of Zagreb, 10000 Zagreb (Croatia); Niksic, T. [Physics Department, Faculty of Science, University of Zagreb, 10000 Zagreb (Croatia); Otsuka, T. [Department of Physics, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Center for Nuclear Study, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824-1321 (United States); Shimizu, N. [Department of Physics, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Center for Nuclear Study, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2011-07-15T23:59:59.000Z

    Microscopic energy density functionals have become a standard tool for nuclear structure calculations, providing an accurate global description of nuclear ground states and collective excitations. For spectroscopic applications, this framework has to be extended to account for collective correlations related to restoration of symmetries broken by the static mean field, and for fluctuations of collective variables. In this paper, we compare two approaches to five-dimensional quadrupole dynamics: the collective Hamiltonian for quadrupole vibrations and rotations and the interacting boson model (IBM). The two models are compared in a study of the evolution of nonaxial shapes in Pt isotopes. Starting from the binding energy surfaces of {sup 192,194,196}Pt, calculated with a microscopic energy density functional, we analyze the resulting low-energy collective spectra obtained from the collective Hamiltonian, and the corresponding IBM Hamiltonian. The calculated excitation spectra and transition probabilities for the ground-state bands and the {gamma}-vibration bands are compared to the corresponding sequences of experimental states.

  12. Quadrupole Collective Dynamics from Energy Density Functionals: Collective Hamiltonian and the Interacting Boson Model

    E-Print Network [OSTI]

    K. Nomura; T. Niksic; T. Otsuka; N. Shimizu; D. Vretenar

    2011-06-14T23:59:59.000Z

    Microscopic energy density functionals (EDF) have become a standard tool for nuclear structure calculations, providing an accurate global description of nuclear ground states and collective excitations. For spectroscopic applications this framework has to be extended to account for collective correlations related to restoration of symmetries broken by the static mean field, and for fluctuations of collective variables. In this work we compare two approaches to five-dimensional quadrupole dynamics: the collective Hamiltonian for quadrupole vibrations and rotations, and the Interacting Boson Model. The two models are compared in a study of the evolution of non-axial shapes in Pt isotopes. Starting from the binding energy surfaces of $^{192,194,196}$Pt, calculated with a microscopic energy density functional, we analyze the resulting low-energy collective spectra obtained from the collective Hamiltonian, and the corresponding IBM-2 Hamiltonian. The calculated excitation spectra and transition probabilities for the ground-state bands and the $\\gamma$-vibration bands are compared to the corresponding sequences of experimental states.

  13. Electrons as probes of dynamics in molecules and clusters : a contribution from Time Dependent Density Functional Theory

    E-Print Network [OSTI]

    Wopperer, P; Reinhard, P -G; Suraud, E

    2014-01-01T23:59:59.000Z

    Various ways to analyze the dynamical response of clusters and molecules to electromagnetic perturbations exist. Particularly rich information can be obtained from measuring the properties of electrons emitted in the course of the excitation dynamics. Such an analysis of electron signals covers total ionization, Photo-Electron Spectra, Photoelectron Angular Distributions, and ideally combined PES/PAD, with a long history in molecular physics, also increasingly used in cluster physics. Recent progress in the design of new light sources (high intensity and/or frequency, ultra short pulses) opens new possibilities for measurements and thus has renewed the interest on the analysis of dynamical scenarios through these observables, well beyond a simple access to a density of states. This, in turn, has motivated many theoretical investigations of the dynamics of electronic emission for molecules and clusters. A theoretical tool of choice is here Time-Dependent Density Functional Theory (TDDFT) propagated in real tim...

  14. On the AU Mic debris disk: density profiles, grain properties and dust dynamics

    E-Print Network [OSTI]

    J. C. Augereau; H. Beust

    2006-04-13T23:59:59.000Z

    We present the first comprehensive analysis of the AU Mic debris disk properties since the system was discovered by Kalas et al. (2004), and we explore whether the dynamical model, successful to reproduce the Beta Pic brightness profile could apply to AU Mic. We calculate the surface density profile of the AU Mic disk by performing the inversion of the near-IR and visible scattered light brightness profiles measured by Liu (2004a) and Krist et al. (2005), respectively. We discuss the grain properties by analysing the blue color of the disk in the visible (Krist et al. 2005) and by fitting the disk spectral energy distribution. We show that irrespective of the mean scattering asymmetry factor of the grains, most of the emission arises from an asymmetric, collisionally-dominated region that peaks close to the surface brightness break around 35 AU. The elementary scatterers at visible wavelengths are found to be sub-micronic, but the inferred size distribution underestimates the amount of large grains, resulting in too low sub-millimeter emissions compared to the observations. From our inversion procedure, we find that the V- to H-band scattering cross sections ratio increases outside 40 AU, in line with the observed color gradient of the disk. We show that a standard, solar-like stellar wind generates a pressure force onto the dust particles that behaves much like a radiation pressure force. With an assumed Mdot ~ 300 Mdot_sun, the wind pressure overcomes the radiation pressure and this effect is enhanced by the stellar flares. This explains the similarity between the Beta Pic and AU Mic brightness profiles. In both cases, the color gradient beyond 120 AU for Beta Pic and 35 AU for AU Mic, is believed to be a direct consequence of the dust dynamics.

  15. The influence of habitat selection and density on the population dynamics of stony coral species of the

    E-Print Network [OSTI]

    Sealey, Kathleen Sullivan

    The influence of habitat selection and density on the population dynamics of stony coral species of Biology, University of Miami, Coral Gables, FL, 33124 USA *Corresponding author: K. Semon Phone: 1-305-284-3013, Fax: 1-305-284-3039, e-mail: ksemon@bio.miami.edu Abstract Although stony corals are most frequently

  16. Topology density correlator on dynamical domain-wall ensembles with nearly frozen topological charge

    E-Print Network [OSTI]

    JLQCD collaboration; H. Fukaya; S. Aoki; G. Cossu; S. Hashimoto; T. Kaneko; J. Noaki

    2014-11-13T23:59:59.000Z

    Global topological charge decorrelates very slowly or even freezes in fine lattice simulations. On the other hand, its local fluctuations are expected to survive and lead to the correct physical results as long as the volume is large enough. We investigate this issue on recently generated configurations including dynamical domain-wall fermions at lattice spacings a = 0.08 fm and finer. We utilize the Yang-Mills gradient flow to define the topological charge density operator and calculate its long-distance correlation, through which we propose a new method for extracting the topological susceptibility in a sub-volume. This method takes care of the finite volume correction, which reduces the bias caused by the global topological charge. Our lattice data clearly show a shorter auto-correlation time than that of the naive definition using the whole lattice, and are less sensitive to the global topological history. Numerical results show a clear sea-quark mass dependence, which agrees well with the prediction of chiral perturbation theory.

  17. Editorial John Hickner, MD, MSc Editor-in-Chief

    E-Print Network [OSTI]

    Alford, Simon

    Health Care, Overland Park, Kan kEVin PEtErSon, MD, MPH University of Minnesota, St. Paul goutHAM rAo, MD

  18. Time-Dynamic Density and Mode Estimation with Application to Fast Mode Tracking

    E-Print Network [OSTI]

    Müller, Hans-Georg

    studied in the recursive density estimation framework (see, for example, Wegman and Davies 1995; Hall; Wegman and Marchette 2003). Real-time density estimation has been treated in Hall and Patil (1994), using

  19. Lessons Learned Tracy Glauser, M.D.

    E-Print Network [OSTI]

    Lessons Learned Tracy Glauser, M.D. Cincinnati Children's Hospital Medical Center #12;Overview 1. Lessons Learned a. NeuroNEXT Executive Committee b. NINDS clinical trials (NSD-K) study section c. PI

  20. Reduced quantum dynamics with arbitrary bath spectral densities: Hierarchical equations of motion based on several different bath decomposition schemes

    SciTech Connect (OSTI)

    Liu, Hao; Zhu, Lili; Bai, Shuming; Shi, Qiang, E-mail: qshi@iccas.ac.cn [Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Zhongguancun, Beijing 100190 (China)] [Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Zhongguancun, Beijing 100190 (China)

    2014-04-07T23:59:59.000Z

    We investigated applications of the hierarchical equation of motion (HEOM) method to perform high order perturbation calculations of reduced quantum dynamics for a harmonic bath with arbitrary spectral densities. Three different schemes are used to decompose the bath spectral density into analytical forms that are suitable to the HEOM treatment: (1) The multiple Lorentzian mode model that can be obtained by numerically fitting the model spectral density. (2) The combined Debye and oscillatory Debye modes model that can be constructed by fitting the corresponding classical bath correlation function. (3) A new method that uses undamped harmonic oscillator modes explicitly in the HEOM formalism. Methods to extract system-bath correlations were investigated for the above bath decomposition schemes. We also show that HEOM in the undamped harmonic oscillator modes can give detailed information on the partial Wigner transform of the total density operator. Theoretical analysis and numerical simulations of the spin-Boson dynamics and the absorption line shape of molecular dimers show that the HEOM formalism for high order perturbations can serve as an important tool in studying the quantum dissipative dynamics in the intermediate coupling regime.

  1. Out-of-equilibrium liquids that form due to dynamics of the molecules that depend on the local density

    E-Print Network [OSTI]

    Richard P. Sear

    2015-03-24T23:59:59.000Z

    RNA molecules in living cells form what look like liquid droplets formed by liquid/liquid phase separation. But unlike the molecules in conventional phase separating mixtures, RNA molecules are transported by molecular motors that consume energy and so are out of equilibrium. Motivated by this we study models with out-of-equilibrium dynamics that depend on the local density. Our simulations suggest that density-dependent dynamics in which the motion of a molecule slows down in the presence of nearby molecules, tend to cause condensation into an out-of-equilibrium liquid state. This out-of-equilibrium state behaves like a liquid in the sense that it coexists with a much more dilute phase, droplets coalesce, and the state has a well-defined surface tension --- which we calculate. Liquid/liquid separation appears to be a very general phenomenon that occurs in and out of equilibrium. We also look at the analogous separation of the two blocks of a block copolymer, in which the monomers of one block have dynamics that depend on the local density of monomers of that block. We find that this block condenses and separates from the monomers of the other block. This is a simple model of the out-of-equilibrium domain formation found in the chromatin in the nucleus of cells.

  2. Dynamics and afterglow light curves of gamma-ray burst blast waves encountering a density bump or void

    SciTech Connect (OSTI)

    Uhm, Z. Lucas; Zhang, Bing, E-mail: uhm@pku.edu.cn, E-mail: zhang@physics.unlv.edu [Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China)

    2014-07-01T23:59:59.000Z

    We investigate the dynamics and afterglow light curves of gamma-ray burst blast waves that encounter various density structures (such as bumps, voids, or steps) in the surrounding ambient medium. We present and explain the characteristic response features that each type of density structure in the medium leaves on the forward shock (FS) and reverse shock (RS) dynamics for blast waves with either a long-lived or short-lived RS. We show that when the ambient medium density drops, the blast waves exhibit in some cases a period of an actual acceleration (even during their deceleration stage) due to adiabatic cooling of blast waves. Comparing numerical examples that have different shapes of bumps or voids, we propose a number of consistency tests that must be satisfied by correct modeling of blast waves. Our model results successfully pass these tests. Employing a Lagrangian description of blast waves, we perform a sophisticated calculation of afterglow emission. We show that as a response to density structures in the ambient medium, the RS light curves produce more significant variations than the FS light curves. Some observed features (such as rebrightenings, dips, or slow wiggles) can be more easily explained within the RS model. We also discuss the origin of these different features imprinted on the FS and RS light curves.

  3. Dynamics of observables and exactly solvable quantum problems: Using time-dependent density functional theory to control quantum systems

    E-Print Network [OSTI]

    Mehdi Farzanehpour; I. V. Tokatly

    2015-06-29T23:59:59.000Z

    We use analytic (current) density-potential maps of time-dependent (current) density functional theory (TD(C)DFT) to inverse engineer analytically solvable time-dependent quantum problems. In this approach the driving potential (the control signal) and the corresponding solution of the Schr\\"odinger equation are parametrized analytically in terms of the basic TD(C)DFT observables. We describe the general reconstruction strategy and illustrate it with a number of explicit examples. First we consider the real space one-particle dynamics driven by a time-dependent electromagnetic field and recover, from the general TDDFT reconstruction formulas, the known exact solution for a driven oscillator with a time-dependent frequency. Then we use analytic maps of the lattice TD(C)DFT to control quantum dynamics in a discrete space. As a first example we construct a time-dependent potential which generates prescribed dynamics on a tight-binding chain. Then our method is applied to the dynamics of spin-1/2 driven by a time dependent magnetic field. We design an analytic control pulse that transfers the system from the ground to excited state and vice versa. This pulse generates the spin flip thus operating as a quantum NOT gate.

  4. Novel Structure and Dynamics of Polymer Thin Films in Supercritical Fluids-Effect of Density Fluctuation

    SciTech Connect (OSTI)

    Koga,T.

    2004-01-01T23:59:59.000Z

    Supercritical carbon dioxide (scCO2) is being used increasingly as a green solvent in polymer processing. The major disadvantage thus far is that only a limited class of polymers, such as fluorinated or silicone-based polymers, can be dissolved in CO2. Here I show that large density fluctuations in scCO2 can significantly enhance the solubility of scCO2 in polymer thin films even when the bulk polymers have very poor miscibility with CO2. By using in situ neutron reflectivity, I found that a wide variety of polymer thin films can swell as much as 30-60% when exposed to scCO2 within a narrow temperature and pressure regime, known as the 'density fluctuation ridge', which defines the maximum density fluctuation amplitude in CO2. Furthermore, the swollen structures induced by the density fluctuation could be frozen by a flash evaporation of CO2 via the vitrification process of the polymer without a formation of void structures. X-ray reflectivity clearly showed that the scCO2 process could be used to produce uniform low-density polymer thin films. I also found that other properties of the vitrified films, such as index of refraction, dielectric constant and glass transition, were correlated with the low-density density profile.

  5. EMC/FDTD/MD FOR MULTIPHYSICS CHARACTERIZATION OF SEMICONDUCTORS AT THZ FREQUENCIES

    E-Print Network [OSTI]

    Knezevic, Irena

    EMC/FDTD/MD FOR MULTIPHYSICS CHARACTERIZATION OF SEMICONDUCTORS AT THZ FREQUENCIES by Keely Willis.1 Ensemble Monte Carlo (EMC) . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 2.2 Finite difference) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 3 EMC/FDTD for 2D analysis of materials with low carrier density . . . . . . . . . 22 3.1 EMC

  6. Babar K. Rao, M.D., Clinical Associate Professor and Acting Chair Donald J. Baker, M.D., Clinical Assistant Professor (Camden)

    E-Print Network [OSTI]

    Garfunkel, Eric

    Hametz, M.D., Clinical Assistant Professor Stanley N. Katz, M.D., Clinical Assistant Professor Steven. Lathrop, M.D., Clinical Associate Professor Lawrence S. Meyers, M.D., Clinical Associate Professor Sandy S

  7. Water adsorption on stepped ZnO surfaces from MD simulation David Raymand a

    E-Print Network [OSTI]

    Goddard III, William A.

    Water adsorption on stepped ZnO surfaces from MD simulation David Raymand a , Adri C.T. van Duin b Keywords: Zinc oxide Water Solid­gas interfaces Construction and use of effective interatomic interactions force-field for use in molecular dynamics simulations of the ZnO­ water system. The force

  8. Out-of-equilibrium liquids that form due to dynamics of the molecules that depend on the local density

    E-Print Network [OSTI]

    Sear, Richard P

    2015-01-01T23:59:59.000Z

    RNA molecules in living cells form what look like liquid droplets formed by liquid/liquid phase separation. But unlike the molecules in conventional phase separating mixtures, RNA molecules are transported by molecular motors that consume energy and so are out of equilibrium. Motivated by this we study models with out-of-equilibrium dynamics that depend on the local density. Our simulations suggest that density-dependent dynamics in which the motion of a molecule slows down in the presence of nearby molecules, tend to cause condensation into an out-of-equilibrium liquid state. This out-of-equilibrium state behaves like a liquid in the sense that it coexists with a much more dilute phase, droplets coalesce, and the state has a well-defined surface tension --- which we calculate. Liquid/liquid separation appears to be a very general phenomenon that occurs in and out of equilibrium. We also look at the analogous separation of the two blocks of a block copolymer, in which the monomers of one block have dynamics t...

  9. Micromagnetic analysis of dynamical bubble-like solitons based on the time domain evolution of the topological density

    SciTech Connect (OSTI)

    Puliafito, Vito, E-mail: vpuliafito@unime.it; Azzerboni, Bruno; Finocchio, Giovanni [Department of Electronic Engineering, Industrial Chemistry and Engineering, University of Messina, 98166 Messina (Italy); Torres, Luis [Department of Applied Physics, University of Salamanca, 37008 Salamanca (Spain); Ozatay, Ozhan [Department of Physics, Bogazici University, 34342 Bebek/Istanbul (Turkey); Hauet, Thomas [Institut Jean Lamour, Université de Lorraine-CNRS UMR 7198, 54506 Nancy (France)

    2014-05-07T23:59:59.000Z

    Dynamical bubble-like solitons have been recently investigated in nanocontact-based spin-torque oscillators with a perpendicular free layer. Those magnetic configurations can be excited also in different geometries as long as they consist of perpendicular materials. Thus, in this paper, a systematic study of the influence of both external field and high current on that kind of dynamics is performed for a spin-valve point-contact geometry where both free and fixed layers present strong perpendicular anisotropy. The usage of the topological density tool highlights the excitation of complex bubble/antibubble configurations. In particular, at high currents, a deformation of the soliton and its simultaneous shift from the contact area are observed and can be ascribable to the Oersted field. Results provide further detailed information on the excitation of solitons in perpendicular materials for application in spintronics, magnonics, and domain wall logic.

  10. Diffraction-Based Density Restraints for Membrane and Membrane-Peptide Molecular Dynamics Simulations

    E-Print Network [OSTI]

    White, Stephen

    or neutron scattering-length density projected along the bilayer normal (5). These profiles represent, California; and z NIST Center for Neutron Research, National Institute of Standards and Technology. INTRODUCTION X-ray and neutron diffraction are commonly used for studying the structure of membrane systems (1

  11. Practical Attacks on Digital Signatures Using MD5 Message Digest

    E-Print Network [OSTI]

    schemes based on MD5 message digest on an example using GPG. Keywords: collision, hash function, MD5 1 on digital signatures on an example using GPG (section 5) and finally an exam- ple of real-world attack

  12. Study of fusion dynamics using Skyrme energy density formalism with different surface corrections

    E-Print Network [OSTI]

    Ishwar Dutt; Narinder K. Dhiman

    2010-11-19T23:59:59.000Z

    Within the framework of Skyrme energy density formalism, we investigate the role of surface corrections on the fusion of colliding nuclei. For this, the coefficient of surface correction was varied between 1/36 and 4/36, and its impact was studied on about 180 reactions. Our detailed investigations indicate a linear relationship between the fusion barrier heights and strength of the surface corrections. Our analysis of the fusion barriers advocate the strength of surface correction of 1/36.

  13. Poster Presentations Marcella Alsan, MD, MPH, PhD

    E-Print Network [OSTI]

    Kay, Mark A.

    15 Poster Presentations Marcella Alsan, MD, MPH, PhD The direct and indirect effects of mass vaccination: Evidence from the 1985 Turkish campaign Michele Barry, MD; Stephen Luby, MD; Nancy Federspiel, PhD Global Health Fellows and Scholars Consortium Cynthia M. Castro, PhD; Abby C. King, PhD; Marcia Stefanick

  14. Driven cavity flow: from molecular dynamics to continuum hydrodynamics

    E-Print Network [OSTI]

    Tiezheng Qian; Xiao-Ping Wang

    2004-03-06T23:59:59.000Z

    Molecular dynamics (MD) simulations have been carried out to investigate the slip of fluid in the lid driven cavity flow where the no-slip boundary condition causes unphysical stress divergence. The MD results not only show the existence of fluid slip but also verify the validity of the Navier slip boundary condition. To better understand the fluid slip in this problem, a continuum hydrodynamic model has been formulated based upon the MD verification of the Navier boundary condition and the Newtonian stress. Our model has no adjustable parameter because all the material parameters (density, viscosity, and slip length) are directly determined from MD simulations. Steady-state velocity fields from continuum calculations are in quantitative agreement with those from MD simulations, from the molecular-scale structure to the global flow. The main discovery is as follows. In the immediate vicinity of the corners where moving and fixed solid surfaces intersect, there is a core partial-slip region where the slippage is large at the moving solid surface and decays away from the intersection quickly. In particular, the structure of this core region is nearly independent of the system size. On the other hand, for sufficiently large system, an additional partial-slip region appears where the slippage varies as $1/r$ with $r$ denoting the distance from the corner along the moving solid surface. The existence of this wide power-law region is in accordance with the asymptotic $1/r$ variation of stress and the Navier boundary condition.

  15. Free Energy Calculation in MD Simulation

    E-Print Network [OSTI]

    Nielsen, Steven O.

    Free Energy Calculation in MD Simulation #12;Basic Thermodynamics Helmoholtz free energy A = U ­ TS + i Ni dA = wrev (reversible, const N V T) eq (22.9) McQuarrie & Simon Gibbs free energy G = U;Implication of Free Energy A B Keq = [A]/[B] Keq = exp (-G0 /RT) G0 = -RT ln Keq G = G0 + RT ln Q G > 0

  16. Electron dynamics in complex environments with real-time time dependent density functional theory in a QM-MM framework

    SciTech Connect (OSTI)

    Morzan, Uriel N.; Ramírez, Francisco F.; Scherlis, Damián A., E-mail: damian@qi.fcen.uba.ar, E-mail: mcgl@qb.ffyb.uba.ar [Departamento de Química Inorgánica, Analítica y Química Física/INQUIMAE, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pab. II, Buenos Aires (C1428EHA) (Argentina); Oviedo, M. Belén; Sánchez, Cristián G. [Departamento de Matemática y Física, Facultad de Ciencias Químicas, INFIQC, Universidad Nacional de Córdoba, Ciudad Universitaria, X5000HUA Córdoba (Argentina)] [Departamento de Matemática y Física, Facultad de Ciencias Químicas, INFIQC, Universidad Nacional de Córdoba, Ciudad Universitaria, X5000HUA Córdoba (Argentina); Lebrero, Mariano C. González, E-mail: damian@qi.fcen.uba.ar, E-mail: mcgl@qb.ffyb.uba.ar [Instituto de Química y Fisicoquímica Biológicas, IQUIFIB, CONICET (Argentina)] [Instituto de Química y Fisicoquímica Biológicas, IQUIFIB, CONICET (Argentina)

    2014-04-28T23:59:59.000Z

    This article presents a time dependent density functional theory (TDDFT) implementation to propagate the Kohn-Sham equations in real time, including the effects of a molecular environment through a Quantum-Mechanics Molecular-Mechanics (QM-MM) hamiltonian. The code delivers an all-electron description employing Gaussian basis functions, and incorporates the Amber force-field in the QM-MM treatment. The most expensive parts of the computation, comprising the commutators between the hamiltonian and the density matrix—required to propagate the electron dynamics—, and the evaluation of the exchange-correlation energy, were migrated to the CUDA platform to run on graphics processing units, which remarkably accelerates the performance of the code. The method was validated by reproducing linear-response TDDFT results for the absorption spectra of several molecular species. Two different schemes were tested to propagate the quantum dynamics: (i) a leap-frog Verlet algorithm, and (ii) the Magnus expansion to first-order. These two approaches were confronted, to find that the Magnus scheme is more efficient by a factor of six in small molecules. Interestingly, the presence of iron was found to seriously limitate the length of the integration time step, due to the high frequencies associated with the core-electrons. This highlights the importance of pseudopotentials to alleviate the cost of the propagation of the inner states when heavy nuclei are present. Finally, the methodology was applied to investigate the shifts induced by the chemical environment on the most intense UV absorption bands of two model systems of general relevance: the formamide molecule in water solution, and the carboxy-heme group in Flavohemoglobin. In both cases, shifts of several nanometers are observed, consistently with the available experimental data.

  17. Ultrafast dynamics of a near-solid-density layer in an intense femtosecond laser-excited plasma

    SciTech Connect (OSTI)

    Adak, Amitava; Chatterjee, Gourab; Kumar Singh, Prashant; Lad, Amit D.; Brijesh, P.; Kumar, G. Ravindra, E-mail: grk@tifr.res.in [Tata Institute of Fundamental Research, Dr. Homi Bhabha Road, Colaba, Mumbai 400005 (India); Blackman, David R. [York Plasma Institute, University of York, Heslington, York YO10 5DQ (United Kingdom); Robinson, A. P. L. [Central Laser Facility, Rutherford-Appleton Laboratory, Chilton, Didcot OX10 0QX (United Kingdom); Pasley, John [York Plasma Institute, University of York, Heslington, York YO10 5DQ (United Kingdom); Central Laser Facility, Rutherford-Appleton Laboratory, Chilton, Didcot OX10 0QX (United Kingdom)

    2014-06-15T23:59:59.000Z

    We report on the picosecond dynamics of a near-solid-density plasma generated by an intense, infrared (??=?800?nm) femtosecond laser using time-resolved pump-probe Doppler spectrometry. An initial red-shift is observed in the reflected third harmonic (??=?266?nm) probe pulse, which gets blue-shifted at longer probe-delays. A combination of particle-in-cell and radiation-hydrodynamics modelling is performed to model the pump laser interaction with the solid target. The results are post-processed to predict the Doppler shift. An excellent agreement is found between the results of such modelling and the experiment. The modelling suggests that the initial inward motion of the critical surface observed in the experiment is due to the passage of a shock-wave-like disturbance, launched by the pump interaction, propagating into the target. Furthermore, in order to achieve the best possible fit to the experimental data, it was necessary to incorporate the effects of bulk ion-acceleration resulting from the electrostatic field set up by the expulsion of electrons from the laser envelope. We also present results of time-resolved pump-probe reflectometry, which are corroborated with the spectrometry results using a 1-D reflectivity model.

  18. Net Zero Residential Test Facility Gaithersburg, MD Solar Photovoltaic Panels

    E-Print Network [OSTI]

    Oak Ridge National Laboratory

    1 Net Zero Residential Test Facility Gaithersburg, MD Solar Photovoltaic Panels Solar Thermal;NZERTF Gaithersburg, MD 3 Objectives Demonstrate Net-Zero Energy for a home similar in nature: · Demonstrate Net-Zero Energy Usage · Measure All Building Loads (Sensible and Latent) · Operate Dedicated

  19. High-dynamic-range extinction mapping of infrared dark clouds: Dependence of density variance with sonic Mach number in molecular clouds

    E-Print Network [OSTI]

    Kainulainen, Jouni

    2012-01-01T23:59:59.000Z

    Measuring the mass distribution of infrared dark clouds (IRDCs) over the wide dynamic range of their column densities is a fundamental obstacle in determining the initial conditions of high-mass star formation and star cluster formation. We present a new technique to derive high-dynamic-range, arcsecond-scale resolution column density data for IRDCs and demonstrate the potential of such data in measuring the density variance - sonic Mach number relation in molecular clouds. We combine near-infrared data from the UKIDSS/Galactic Plane Survey with mid-infrared data from the Spitzer/GLIMPSE survey to derive dust extinction maps for a sample of ten IRDCs. We then examine the linewidths of the IRDCs using 13CO line emission data from the FCRAO/Galactic Ring Survey and derive a column density - sonic Mach number relation for them. For comparison, we also examine the relation in a sample of nearby molecular clouds. The presented column density mapping technique provides a very capable, temperature independent tool f...

  20. Serial Intraoperative MR Imaging of Brain Shift Arya Nabavi, M.D.1

    E-Print Network [OSTI]

    Serial Intraoperative MR Imaging of Brain Shift Arya Nabavi, M.D.1 , Peter McL. Black, M.D. Ph.D.1 , David T. Gering, M.S.4 , Carl-Fredrik Westin, Ph.D3 , Vivek Mehta, M.D.1 , Richard S. Pergolizzi Jr., M, M.D., Ph.D.2 , William M. Wells III, Ph.D4 ., Ron Kikinis, M.D.3 , Ferenc A. Jolesz, M.D.3 1

  1. Far-from-equilibrium dynamics of a strongly coupled non-Abelian plasma with non-zero charge density or external magnetic field

    E-Print Network [OSTI]

    Fuini, John F

    2015-01-01T23:59:59.000Z

    Using holography, we study the evolution of a spatially homogeneous, far from equilibrium, strongly coupled N=4 supersymmetric Yang-Mills plasma with a non-zero charge density or a background magnetic field. This gauge theory problem corresponds, in the dual gravity description, to an initial value problem in Einstein-Maxwell theory with homogeneous but anisotropic initial conditions. We explore the dependence of the equilibration process on different aspects of the initial departure from equilibrium and, while controlling for these dependencies, examine how the equilibration dynamics are affected by the presence of a non-vanishing charge density or an external magnetic field. The equilibration dynamics are remarkably insensitive to the addition of even large chemical potentials or magnetic fields; the equilibration time is set primarily by the form of the initial departure from equilibrium. For initial deviations from equilibrium which are well localized in scale, we formulate a simple model for equilibratio...

  2. Far-from-equilibrium dynamics of a strongly coupled non-Abelian plasma with non-zero charge density or external magnetic field

    E-Print Network [OSTI]

    John F. Fuini III; Laurence G. Yaffe

    2015-03-24T23:59:59.000Z

    Using holography, we study the evolution of a spatially homogeneous, far from equilibrium, strongly coupled N=4 supersymmetric Yang-Mills plasma with a non-zero charge density or a background magnetic field. This gauge theory problem corresponds, in the dual gravity description, to an initial value problem in Einstein-Maxwell theory with homogeneous but anisotropic initial conditions. We explore the dependence of the equilibration process on different aspects of the initial departure from equilibrium and, while controlling for these dependencies, examine how the equilibration dynamics are affected by the presence of a non-vanishing charge density or an external magnetic field. The equilibration dynamics are remarkably insensitive to the addition of even large chemical potentials or magnetic fields; the equilibration time is set primarily by the form of the initial departure from equilibrium. For initial deviations from equilibrium which are well localized in scale, we formulate a simple model for equilibration times which agrees quite well with our results.

  3. The Centre for Blood Research Jos Lpez, MD

    E-Print Network [OSTI]

    Strynadka, Natalie

    The Centre for Blood Research José López, MD Executive Vice-President of Research Puget Sound Blood for Blood Research Von Willebrand factor (VWF) is the largest protein in the blood and involved in both

  4. A time-dependent momentum-space density functional theoretical approach for electron transport dynamics in molecular devices

    E-Print Network [OSTI]

    Chu, Shih-I

    for electron transport dynamics in molecular devices Zhongyuan Zhou(a) and Shih-I Chu Department of Chemistry and structures PACS 85.65.+h ­ Molecular electronic devices PACS 71.15.Pd ­ Molecular dynamics calculations (Carr) approach in momentum (P) space for the study of electron transport in molecular devices under arbitrary

  5. A time-dependent momentum-space density functional theoretical approach for electron transport dynamics in molecular devices

    E-Print Network [OSTI]

    Chu, Shih-I; Zhou, Zhongyuan

    2009-10-27T23:59:59.000Z

    We propose a time-dependent density functional theoretical (TDDFT) approach in momentum (\\mathcal{P} ) space for the study of electron transport in molecular devices under arbitrary biases. The basic equation of motion, which is a time...

  6. Quasilinear dynamics of a cloud of hot electrons propagating through a plasma with decreasing density and temperature

    SciTech Connect (OSTI)

    Foroutan, G. [Department of Physics, Faculty of Science, Sahand University of Technology, Tabriz 51335-1996 (Iran, Islamic Republic of); School of Physics, The University of Sydney, Sydney NSW 2006 (Australia); Khalilpour, H.; Moslehi-Fard, M. [Faculty of Physics, Tabriz University, Tabriz 51664 (Iran, Islamic Republic of); Li, B.; Robinson, P. A. [School of Physics, University of Sydney, Sydney NSW 2006 (Australia)

    2008-12-15T23:59:59.000Z

    The effects of plasma inhomogeneities on the propagation of a cloud of hot electrons through a cold background plasma and generation of Langmuir waves are investigated using numerical simulations of the quasilinear equations. It is found that in a plasma with decreasing density the quasilinear relaxation of the electron distribution in velocity space is accelerated and the levels of the generated Langmuir waves are enhanced. The magnitude of the induced emission rate is increased and its maximum value moves to lower velocities. Due to density gradient the height of plateau shows an increase at small distances and a corresponding decrease at large distances. It is also found that in a plasma with decreasing temperature, the relaxation of the beam is retarded, the spectral density of Langmuir waves is broadened, and the height of the plateau decreases below its value in a uniform plasma. In the presence of both density and temperature gradients, at given position, the height and upper boundary of the plateau and the level of Langmuir waves are all increased at small velocities. The spatial expansion of the beam is increased by the plasma inhomogeneities, but its average velocity of propagation decreases. Initially, at a given position, the velocity at the upper boundary of the plateau is smaller in the presence of the density gradient than in the uniform plasma but the reverse is true at longer times. Due to temperature gradient, at large times and small distances, the upper boundary of the plateau is increased above its value in the uniform plasma. Because of fast relaxation, the value of the lower boundary of the plateau in the plasma with decreasing density is always less than its value in the uniform plasma. It is found that the local velocity of the beam decreases when the density gradient is present. The local velocity spread of the beam remains unchanged during the propagation of the beam in the uniform plasma, but increases in the presence of inhomogeneities.

  7. A molecular dynamics study of polymer/graphene interfacial systems

    SciTech Connect (OSTI)

    Rissanou, Anastassia N.; Harmandaris, Vagelis [Department of Mathematics and Applied Mathematics, University of Crete, GR-71409, Heraklion, Crete, Greece and Institute of Applied and Computational Mathematics (IACM), Foundation for Research and Technology Hellas (FORTH), GR-71110, Heraklion, Cret (Greece)

    2014-05-15T23:59:59.000Z

    Graphene based polymer nanocomposites are hybrid materials with a very broad range of technological applications. In this work, we study three hybrid polymer/graphene interfacial systems (polystyrene/graphene, poly(methyl methacrylate)/graphene and polyethylene/graphene) through detailed atomistic molecular dynamics (MD) simulations. Density profiles, structural characteristics and mobility aspects are being examined at the molecular level for all model systems. In addition, we compare the properties of the hybrid systems to the properties of the corresponding bulk ones, as well as to theoretical predictions.

  8. Charge transport through bio-molecular wires in a solvent: Bridging molecular dynamics and model Hamiltonian approaches

    E-Print Network [OSTI]

    R. Gutierrez; R. Caetano; P. B. Woiczikowski; T. Kubar; M. Elstner; G. Cuniberti

    2009-01-22T23:59:59.000Z

    We present a hybrid method based on a combination of quantum/classical molecular dynamics (MD) simulations and a mod el Hamiltonian approach to describe charge transport through bio-molecular wires with variable lengths in presence o f a solvent. The core of our approach consists in a mapping of the bio-molecular electronic structure, as obtained f rom density-functional based tight-binding calculations of molecular structures along MD trajectories, onto a low di mensional model Hamiltonian including the coupling to a dissipative bosonic environment. The latter encodes fluctuat ion effects arising from the solvent and from the molecular conformational dynamics. We apply this approach to the c ase of pG-pC and pA-pT DNA oligomers as paradigmatic cases and show that the DNA conformational fluctuations are essential in determining and supporting charge transport.

  9. Development of a high dynamic range spectroscopic system for observation of neutral hydrogen atom density distribution in Large Helical Device core plasma

    SciTech Connect (OSTI)

    Fujii, K., E-mail: fujii@me.kyoto-u.ac.jp; Atsumi, S.; Watanabe, S.; Shikama, T.; Hasuo, M. [Department of Mechanical Engineering and Science, Graduate School of Engineering, Kyoto University, Kyoto 606-8540 (Japan)] [Department of Mechanical Engineering and Science, Graduate School of Engineering, Kyoto University, Kyoto 606-8540 (Japan); Goto, M.; Morita, S. [National Institute for Fusion Science, Toki 509-5292 (Japan)] [National Institute for Fusion Science, Toki 509-5292 (Japan)

    2014-02-15T23:59:59.000Z

    We report development of a high dynamic range spectroscopic system comprising a spectrometer with 30% throughput and a camera with a low-noise fast-readout complementary metal-oxide semiconductor sensor. The system achieves a 10{sup 6} dynamic range (?20 bit resolution) and an instrumental function approximated by a Voigt profile with Gauss and Lorentz widths of 31 and 0.31 pm, respectively, for 656 nm light. The application of the system for line profile observations of the Balmer-? emissions from high temperature plasmas generated in the Large Helical Device is also presented. In the observed line profiles, emissions are detected in far wings more than 1.0 nm away from the line center, equivalent to neutral hydrogen atom kinetic energies above 1 keV. We evaluate atom density distributions in the core plasma by analyzing the line profiles.

  10. Enhanced reactivity of nanoenergetic materials: A first-principles molecular dynamics study based on divide-and-conquer density

    E-Print Network [OSTI]

    Southern California, University of

    a stage for first-principles molecular dynamics simulation of thermite reaction at an Al/Fe2O3 interface experimental observation in thermite nanowire arrays. © 2009 American Institute of Physics. DOI: 10 to drive nanofluidics.1,2 Most widely used energetic materials for device integration are thermites, which

  11. Low power low-density parity-checking (ldpc) codes decoder design using dynamic voltage and frequency scaling

    E-Print Network [OSTI]

    Wang, Weihuang

    2009-05-15T23:59:59.000Z

    This thesis presents a low-power LDPC decoder design based on speculative scheduling of energy necessary to decode dynamically varying data frame in both block-fading channels and general AWGN channels. A model of a memory-efficient low-power high...

  12. Spin and charge dynamics of the two-dimensional {ital t}-{ital J} model at intermediate electron densities: Absence of spin-charge separation

    SciTech Connect (OSTI)

    Eder, R.; Ohta, Y. [Department of Applied Physics, Nagoya University, Nagoya 464-01 (Japan)] [Department of Applied Physics, Nagoya University, Nagoya 464-01 (Japan)

    1995-05-01T23:59:59.000Z

    We present an exact diagonalization study of the dynamical spin and density correlation functions in small clusters of the {ital t}-{ital J} model, focusing on the regime of intermediate and low electron densities, {rho}{sub {ital e}}{lt}0.5. In two dimensions (2D) both correlation functions agree remarkably well with the convolution of the single-particle spectral function, i.e., the simplest estimate possible within a Fermi-liquid picture. Deviations from the convolution are shown to originate from symmetry-related selection rules, which are unaccounted for in the convolution estimate. For all fillngs under consideration, we show that the low-energy peaks originate from particle-hole excitations between the Fermi momenta, as expected for a Fermi liquid. We contrast this with the behavior in 1D, where spin and density correlation function show the differences characteristic of spin-charge separation and where neither correlation function is approximated well by the convolution.

  13. FPGA-BASED MULTIGRID COMPUTATION FOR MOLECULAR DYNAMICS SIMULATIONS

    E-Print Network [OSTI]

    Herbordt, Martin

    FPGA-BASED MULTIGRID COMPUTATION FOR MOLECULAR DYNAMICS SIMULATIONS Yongfeng Gu Martin C. Herbordt serial code. 1. INTRODUCTION Molecular Dynamics simulations (MD) are a fundamental tool for gaining Computer Architecture and Automated Design Laboratory Department of Electrical and Computer Engineering

  14. Einstein M.D. Program 20132014 applicant guide

    E-Print Network [OSTI]

    Emmons, Scott

    Einstein M.D. Program 2013­2014 applicant guide O F Y E S H I V A U N I V E R S I T Y Albert Einstein College of Medicine #12;2 Welcome Explore how Einstein can give you the skills to develop, learning opportunities and experiences that create the unique educational environment at Einstein

  15. Einstein M.D. Program 20112012 applicant guide

    E-Print Network [OSTI]

    Jenny, Andreas

    Einstein M.D. Program 2011­2012 applicant guide O F Y E S H I V A U N I V E R S I T Y Albert Einstein College of Medicine #12;2 Welcome Explore how Einstein can give you the skills to develop, learning opportunities and experiences that create the unique educational environment at Einstein

  16. LSUHSC NO Leadership Program Director, Augusto Ochoa, MD

    E-Print Network [OSTI]

    D: Project 8 Yan Cui, PhD: COBRE Graduate Mentor Internal Advisory Committee Joseph Moerschbaecher, III: Jonna Ellis Promising Junior Investigators Project 2: Jovanny Zabaleta, PhD Project 3: Paulo Rodriguez, PhD Project 4: Timothy Foster, PhD Project 5: John Schieffelin, MD Tulane University Project 6

  17. Diabetes A Growing Epidemic Michael McKee, MD, MPH

    E-Print Network [OSTI]

    Goldman, Steven A.

    Diabetes ­ A Growing Epidemic Michael McKee, MD, MPH March 28, 2013 #12;Goals Diabetes Introduction Types of Diabetes Testing Prevention Treatments #12;In Memory of Benno Houver Bernd "Benno" Houver (1973-2013) #12;Diabetes Info 25.8 million people in the USA (8.3%) have diabetes ~25% of people with diabetes do

  18. Excited-state quantum phase transitions in systems with two degrees of freedom: Level density, level dynamics, thermal properties

    SciTech Connect (OSTI)

    Stránský, Pavel [Institute of Particle and Nuclear Physics, Faculty of Mathematics and Physics, Charles University, V Holešovi?kách 2, 18000 Prague (Czech Republic); Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, 04510, México, D.F. (Mexico); Macek, Michal [Racah Institute of Physics, The Hebrew University, 91904 Jerusalem (Israel); Institute of Particle and Nuclear Physics, Faculty of Mathematics and Physics, Charles University, V Holešovi?kách 2, 18000 Prague (Czech Republic); Cejnar, Pavel, E-mail: pavel.cejnar@mff.cuni.cz [Institute of Particle and Nuclear Physics, Faculty of Mathematics and Physics, Charles University, V Holešovi?kách 2, 18000 Prague (Czech Republic)

    2014-06-15T23:59:59.000Z

    Quantum systems with a finite number of freedom degrees f develop robust singularities in the energy spectrum of excited states as the system’s size increases to infinity. We analyze the general form of these singularities for low f, particularly f=2, clarifying the relation to classical stationary points of the corresponding potential. Signatures in the smoothed energy dependence of the quantum state density and in the flow of energy levels with an arbitrary control parameter are described along with the relevant thermodynamical consequences. The general analysis is illustrated with specific examples of excited-state singularities accompanying the first-order quantum phase transition. -- Highlights: •ESQPTs found in infinite-size limit of systems with low numbers of freedom degrees f. •ESQPTs related to non-analytical evolutions of classical phase–space properties. •ESQPT signatures analyzed for general f, particularly f=2, extending known case f=1. •ESQPT signatures identified in smoothened density and flow of energy spectrum. •ESQPTs shown to induce a new type of thermodynamic anomalies.

  19. Effect of dimerization on dynamics of spin-charge separation in Pariser-Parr-Pople model: A time-dependent density matrix renormalization group study

    E-Print Network [OSTI]

    Tirthankar Dutta; S. Ramasesha

    2011-12-29T23:59:59.000Z

    We investigate the effect of static electron-phonon coupling, on real-time dynamics of spin and charge transport in $\\pi$-conjugated polyene chains. The polyene chain is modeled by the Pariser-Parr-Pople Hamiltonian with dimerized nearest-neighbor parameter $t_{0}(1+\\delta)$ for short bonds and $t_{0}(1-\\delta)$ for long bonds, and long-range electron-electron interactions. We follow the time evolution of the spin and charge using time-dependent density matrix renormalization group technique, when a hole is injected at one end of the chain in its ground state. We find that spin and charge dynamics followed through spin and charge velocities, depend both on chain length and extent of dimerization, $\\delta$. Analysis of the results requires focusing on physical quantities such as average spin and charge polarizations, particularly in the large dimerization limit. In the dimerization range 0.0 $\\le$ $\\delta$ $\\le$ 0.15, spin-charge dynamics is found to have a well defined behavior, with spin-charge separation (measured as the ratio of charge velocity to spin velocity) as well as, the total amount of charge and spin transported in a given time, along the chain, decreasing as dimerization increases. However, in the range 0.3 $\\le$ $\\delta$ $\\le$ 0.5, it is observed that the dynamics of spin and charge transport becomes complicated. It is observed that for large $\\delta$ values, spin-charge separation is suppressed and the injected hole fails to travel the entire length of the chain.

  20. Substructured multibody molecular dynamics.

    SciTech Connect (OSTI)

    Grest, Gary Stephen; Stevens, Mark Jackson; Plimpton, Steven James; Woolf, Thomas B. (Johns Hopkins University, Baltimore, MD); Lehoucq, Richard B.; Crozier, Paul Stewart; Ismail, Ahmed E.; Mukherjee, Rudranarayan M. (Rensselaer Polytechnic Institute, Troy, NY); Draganescu, Andrei I.

    2006-11-01T23:59:59.000Z

    We have enhanced our parallel molecular dynamics (MD) simulation software LAMMPS (Large-scale Atomic/Molecular Massively Parallel Simulator, lammps.sandia.gov) to include many new features for accelerated simulation including articulated rigid body dynamics via coupling to the Rensselaer Polytechnic Institute code POEMS (Parallelizable Open-source Efficient Multibody Software). We use new features of the LAMMPS software package to investigate rhodopsin photoisomerization, and water model surface tension and capillary waves at the vapor-liquid interface. Finally, we motivate the recipes of MD for practitioners and researchers in numerical analysis and computational mechanics.

  1. End-to-End Rate-Distortion Optimized MD Mode Selection for Multiple Description Video Coding

    E-Print Network [OSTI]

    Apostolopoulos, John G.

    Multiple description (MD) video coding can be used to reduce the detrimental effects caused by transmission over lossy packet networks. A number of approaches have been proposed for MD coding, where each provides a different ...

  2. COMMISSION ON HEALTH SCIENCE, EDUCATION, AND P. Roy Vagelos, M.D.

    E-Print Network [OSTI]

    Lin, Xiaodong

    Johnson & Johnson Barbara Bell Coleman Chairperson Amelior Foundation Norman H. Edelman, M.D. Vice Princeton University Steven A. Schroeder, M.D. President and CEO The Robert Wood Johnson Foundation Harold and Dentistry of New Jersey Samuel O. Thier, M.D. President and CEO Partners HealthCare System, Inc. #12

  3. Asbestos-related diseases in automobile mechanics Jacques Ameille, MD1

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1 Asbestos-related diseases in automobile mechanics Jacques Ameille, MD1 , Nicole Rosenberg, MD2-related diseases in automobile mechanics Corresponding author Jacques Ameille, MD, Unité de pathologie plaques, automobile mechanics, HRCT inserm-00671970,version1-20Feb2012 Author manuscript, published

  4. Influence of longitudinal isotope substitution on the thermal conductivity of carbon nanotubes: Results of nonequilibrium molecular dynamics and local density functional calculations

    SciTech Connect (OSTI)

    Leroy, Frédéric, E-mail: f.leroy@theo.chemie.tu-darmstadt.de; Böhm, Michael C., E-mail: boehm@theo.chemie.tu-darmstadt.de [Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, D-64287 Darmstadt (Germany); Schulte, Joachim [Bruker Biospin GmbH, Silberstreifen, D-76287 Rheinstetten (Germany)] [Bruker Biospin GmbH, Silberstreifen, D-76287 Rheinstetten (Germany); Balasubramanian, Ganesh [Department of Mechanical Engineering, Iowa State University, Ames, Iowa 50011 (United States)] [Department of Mechanical Engineering, Iowa State University, Ames, Iowa 50011 (United States)

    2014-04-14T23:59:59.000Z

    We report reverse nonequilibrium molecular dynamics calculations of the thermal conductivity of isotope substituted (10,10) carbon nanotubes (CNTs) at 300 K. {sup 12}C and {sup 14}C isotopes both at 50% content were arranged either randomly, in bands running parallel to the main axis of the CNTs or in bands perpendicular to this axis. It is found that the systems with randomly distributed isotopes yield significantly reduced thermal conductivity. In contrast, the systems where the isotopes are organized in patterns parallel to the CNTs axis feature no reduction in thermal conductivity when compared with the pure {sup 14}C system. Moreover, a reduction of approximately 30% is observed in the system with the bands of isotopes running perpendicular to the CNT axis. The computation of phonon dispersion curves in the local density approximation and classical densities of vibrational states reveal that the phonon structure of carbon nanotubes is conserved in the isotope substituted systems with the ordered patterns, yielding high thermal conductivities in spite of the mass heterogeneity. In order to complement our conclusions on the {sup 12}C-{sup 14}C mixtures, we computed the thermal conductivity of systems where the {sup 14}C isotope was turned into pseudo-atoms of 20 and 40 atomic mass units.

  5. Einstein M.D. Program 20142015 APPLICANT GUIDE

    E-Print Network [OSTI]

    Emmons, Scott

    Einstein M.D. Program 2014­2015 APPLICANT GUIDE O F Y E S H I V A U N I V E R S I T Y Albert Einstein College of Medicine #12;2 Welcome Explore how Einstein can give you the skills to develop at Einstein. There are 183 students in the first- year class. 8,193 applicants applied for entrance and 1

  6. Pasta Nucleosynthesis: Molecular dynamics simulations of nuclear statistical equilibrium

    E-Print Network [OSTI]

    M. E. Caplan; A. S. Schneider; C. J. Horowitz; D. K. Berry

    2014-12-29T23:59:59.000Z

    Background: Exotic non-spherical nuclear pasta shapes are expected in nuclear matter at just below saturation density because of competition between short range nuclear attraction and long range Coulomb repulsion. Purpose: We explore the impact of nuclear pasta on nucleosynthesis, during neutron star mergers, as cold dense nuclear matter is ejected and decompressed. Methods: We perform classical molecular dynamics simulations with 51200 and 409600 nucleons, that are run on GPUs. We expand our simulation region to decompress systems from an initial density of 0.080 fm^{-3} down to 0.00125 fm^{-3}. We study proton fractions of Y_P=0.05, 0.10, 0.20, 0.30, and 0.40 at T =0.5, 0.75, and 1.0 MeV. We calculate the composition of the resulting systems using a cluster algorithm. Results: We find final compositions that are in good agreement with nuclear statistical equilibrium models for temperatures of 0.75 and 1 MeV. However, for proton fractions greater than Y_P=0.2 at a temperature of T = 0.5 MeV, the MD simulations produce non-equilibrium results with large rod-like nuclei. Conclusions: Our MD model is valid at higher densities than simple nuclear statistical equilibrium models and may help determine the initial temperatures and proton fractions of matter ejected in mergers.

  7. Research Paper j Using Petri Net Tools to Study Properties and Dynamics of

    E-Print Network [OSTI]

    Rubin, Daniel L.

    Research Paper j Using Petri Net Tools to Study Properties and Dynamics of Biological Systems MOR PELEG, PHD, DANIEL RUBIN, MD, MSC, RUSS B. ALTMAN, MD, PHD A b s t r a c t Petri Nets (PNs concurrent dynamic systems is Petri Nets (PNs).1 An advantage of PNs is that they can represent system

  8. Brain-Computer Interfaces in Medicine Jerry J. Shih, MD; Dean J. Krusienski, PhD; and Jonathan R. Wolpaw, MD

    E-Print Network [OSTI]

    Nehorai, Arye

    Brain-Computer Interfaces in Medicine Jerry J. Shih, MD; Dean J. Krusienski, PhD; and Jonathan R. Wolpaw, MD Abstract Brain-computer interfaces (BCIs) acquire brain signals, analyze them, and translate, electrocorticographic, and other brain signals for increasingly complex control of cursors, robotic arms, prostheses

  9. UC Davis-LLNL Scientific Advisory Committee Timothy Albertson, MD, PhD, Vice Chair, Internal Medicine

    E-Print Network [OSTI]

    Carmichael, Owen

    UC Davis-LLNL Scientific Advisory Committee Timothy Albertson, MD, PhD, Vice Chair, Internal Berglund, MD, PhD, CTSC Program Director Stuart Cohen, MD, Head of Infection Control, UCDMC Jeffrey Elias, PhD, Manager, Grant Coordination **Captain** Hernando Garzon, MD, Emergency Medicine, Kaiser Jeffrey

  10. Time-resolved infrared absorption studies of the solvent-dependent vibrational relaxation dynamics of chlorine dioxide

    SciTech Connect (OSTI)

    Bolinger, Joshua C.; Bixby, Teresa J.; Reid, Philip J. [Box 351700, Department of Chemistry, University of Washington, Seattle, Washington 98195 (United States)

    2005-08-22T23:59:59.000Z

    We report a series of time-resolved infrared absorption studies on chlorine dioxide (OClO) dissolved in H{sub 2}O, D{sub 2}O, and acetonitrile. Following the photoexcitation at 401 nm, the evolution in optical density for frequencies corresponding to asymmetric stretch of OClO is measured with a time resolution of 120{+-}50 fs. The experimentally determined optical-density evolution is compared with theoretical models of OClO vibrational relaxation derived from collisional models as well as classical molecular-dynamics (MD) studies. The vibrational relaxation rates in D{sub 2}O are reduced by a factor of 3 relative to H{sub 2}O consistent with the predictions of MD. This difference reflects modification of the frequency-dependent solvent-solute coupling accompanying isotopic substitution of the solvent. Also, the geminate-recombination quantum yield for the primary photofragments resulting in the reformation of ground-state OClO is reduced in D{sub 2}O relative to H{sub 2}O. It is proposed that this reduction reflects enhancement of the dissociation rate accompanying vibrational excitation along the asymmetric-stretch coordinate. In contrast to H{sub 2}O and D{sub 2}O, the vibrational-relaxation dynamics in acetonitrile are not well described by the theoretical models. Reproduction of the optical-density evolution in acetonitrile requires significant modification of the frequency-dependent solvent-solute coupling derived from MD. It is proposed that this modification reflects vibrational-energy transfer from the asymmetric stretch of OClO to the methyl rock of acetonitrile. In total, the results presented here provide a detailed description of the solvent-dependent geminate-recombination and vibrational-relaxation dynamics of OClO in solution.

  11. DOE - Office of Legacy Management -- Johns Hopkins University - MD 02

    Office of Legacy Management (LM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOn AprilA group currentBradleyTable ofArizonaBuffaloJohns Hopkins University - MD 02 FUSRAP

  12. Hydration structure of salt solutions from ab initio molecular dynamics

    SciTech Connect (OSTI)

    Bankura, Arindam; Carnevale, Vincenzo; Klein, Michael L. [Institute for Computational Molecular Science and Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122 (United States)

    2013-01-07T23:59:59.000Z

    The solvation structures of Na{sup +}, K{sup +}, and Cl{sup -} ions in aqueous solution have been investigated using density functional theory (DFT) based Car-Parrinello (CP) molecular dynamics (MD) simulations. CPMD trajectories were collected for systems containing three NaCl or KCl ion pairs solvated by 122 water molecules using three different but commonly employed density functionals (BLYP, HCTH, and PBE) with electron correlation treated at the level of the generalized gradient approximation (GGA). The effect of including dispersion forces was analyzed through the use of an empirical correction to the DFT-GGA scheme. Special attention was paid to the hydration characteristics, especially the structural properties of the first solvation shell of the ions, which was investigated through ion-water radial distribution functions, coordination numbers, and angular distribution functions. There are significant differences between the present results obtained from CPMD simulations and those provided by classical MD based on either the CHARMM force field or a polarizable model. Overall, the computed structural properties are in fair agreement with the available experimental results. In particular, the observed coordination numbers 5.0-5.5, 6.0-6.4, and 6.0-6.5 for Na{sup +}, K{sup +}, and Cl{sup -}, respectively, are consistent with X-ray and neutron scattering studies but differ somewhat from some of the many other recent computational studies of these important systems. Possible reasons for the differences are discussed.

  13. Density functional theory study of the structural, electronic, lattice dynamical, and thermodynamic properties of Li4SiO4 and its capability for CO2 capture

    SciTech Connect (OSTI)

    Duan, Yuhua; Parlinski, K.

    2011-01-01T23:59:59.000Z

    The structural, electronic, lattice dynamical, optical, thermodynamic, and CO{sub 2} capture properties of monoclinic and triclinic phases of Li{sub 4}SiO{sub 4} are investigated by combining density functional theory with phonon lattice dynamics calculations. We found that these two phases have some similarities in their bulk and thermodynamic properties. The calculated bulk modulus and the cohesive energies of these two phases are close to each other. Although both of them are insulators, the monoclinic phase of Li{sub 4}SiO{sub 4} has a direct band gap of 5.24 eV while the triclinic Li{sub 4}SiO{sub 4} phase has an indirect band gap of 4.98 eV. In both phases of Li{sub 4}SiO{sub 4}, the s orbital of O mainly contributes to the lower-energy second valence band (VB{sub 2}) and the p orbitals contribute to the fist valence band (VB{sub 1}) and the conduction bands (CBs). The s orbital of Si mainly contributes to the lower portions of the VB1 and VB{sub 2}, and Si p orbitals mainly contribute to the higher portions of the VB{sub 1} and VB{sub 2}. The s and p orbitals of Li contribute to both VBs and to CBs, and Li p orbitals have a higher contribution than the Li s orbital. There is possibly a phonon soft mode existing in triclinic {gamma}-Li{sub 4}SiO{sub 4}; in the monoclinic Li{sub 4}SiO{sub 4}, there are three phonon soft modes, which correspond to the one type of Li disordered over a few sites. Their LO-TO splitting indicates that both phases of Li{sub 4}SiO{sub 4} are polar anisotropic materials. The calculated infrared absorption spectra for LO and TO modes are different for these two phases of Li{sub 4}SiO{sub 4}. The calculated relationships of the chemical potential versus temperature and CO{sub 2} pressure for reaction of Li{sub 4}SiO{sub 4} with CO{sub 2} shows that Li{sub 4}SiO{sub 4} could be a good candidate for a high-temperature CO{sub 2} sorbent while used for postcombustion capture technology.

  14. The Molecular Structure of a Phosphatidylserine Bilayer Determined by Scattering and Molecular Dynamics Simulations

    SciTech Connect (OSTI)

    Pan, Jianjun [University of South Florida, Tampa (USF)] [University of South Florida, Tampa (USF); Cheng, Xiaolin [ORNL] [ORNL; Monticelli, Luca [Institut National de la Santé et de la Recherche Médicale (INSERM) and INTS, France] [Institut National de la Santé et de la Recherche Médicale (INSERM) and INTS, France; Heberle, Frederick A [ORNL] [ORNL; Kucerka, Norbert [Atomic Energy of Canada Limited (AECL), Canadian Neutron Beam Centre (CNBC) and Comenius University,] [Atomic Energy of Canada Limited (AECL), Canadian Neutron Beam Centre (CNBC) and Comenius University,; Tieleman, D. Peter [University of Calgary, ALberta, Canada] [University of Calgary, ALberta, Canada; Katsaras, John [ORNL] [ORNL

    2014-01-01T23:59:59.000Z

    Phosphatidylserine (PS) lipids play essential roles in biological processes, including enzyme activation and apoptosis. We report on the molecular structure and atomic scale interactions of a fluid bilayer composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylserine (POPS). A scattering density profile model, aided by molecular dynamics (MD) simulations, was developed to jointly refine different contrast small-angle neutron and X-ray scattering data, which yielded a lipid area of 62.7 A2 at 25 C. MD simulations with POPS lipid area constrained at different values were also performed using all-atom and aliphatic united-atom models. The optimal simulated bilayer was obtained using a model-free comparison approach. Examination of the simulated bilayer, which agrees best with the experimental scattering data, reveals a preferential interaction between Na+ ions and the terminal serine and phosphate moieties. Long-range inter-lipid interactions were identified, primarily between the positively charged ammonium, and the negatively charged carboxylic and phosphate oxygens. The area compressibility modulus KA of the POPS bilayer was derived by quantifying lipid area as a function of surface tension from area-constrained MD simulations. It was found that POPS bilayers possess a much larger KA than that of neutral phosphatidylcholine lipid bilayers. We propose that the unique molecular features of POPS bilayers may play an important role in certain physiological functions.

  15. Anharmonic lattice dynamics of Ag2O studied by inelastic neutron scattering and first-principles molecular dynamics simulations

    SciTech Connect (OSTI)

    Lan, Tian [California Institute of Technology, Pasadena] [California Institute of Technology, Pasadena; Li, Chen [ORNL] [ORNL; Niedziela, Jennifer L [ORNL] [ORNL; Smith, Hillary [California Institute of Technology, Pasadena] [California Institute of Technology, Pasadena; Abernathy, Douglas L [ORNL] [ORNL; Rossman, George [California Institute of Technology, Pasadena] [California Institute of Technology, Pasadena; Fultz, B. [California Institute of Technology, Pasadena] [California Institute of Technology, Pasadena

    2014-01-01T23:59:59.000Z

    Inelastic neutron scattering measurements on silver oxide (Ag2O) with the cuprite structure were performed at temperatures from 40 to 400 K, and Fourier transform far-infrared spectra were measured from 100 to 300 K. The measured phonon densities of states and the infrared spectra showed unusually large energy shifts with temperature, and large linewidth broadenings. First principles molecular dynamics (MD) calculations were performed at various temperatures, successfully accounting for the negative thermal expansion (NTE) and local dynamics. Using the Fourier-transformed velocity autocorrelation method, the MD calculations reproduced the large anharmonic effects of Ag2O, and were in excellent agreement with the neutron scattering data. The quasiharmonic approximation (QHA) was less successful in accounting for much of the phonon behavior. The QHA could account for some of the NTE below 250 K, although not at higher temperatures. Strong anharmonic effects were found for both phonons and for the NTE. The lifetime broadenings of Ag2O were explained by anharmonic perturbation theory, which showed rich interactions between the Ag-dominated modes and the O-dominated modes in both up- and down-conversion processes.

  16. Phenol-benzene complexation dynamics: Quantum chemistry calculation, molecular dynamics simulations, and two dimensional IR spectroscopy

    E-Print Network [OSTI]

    Fayer, Michael D.

    Phenol-benzene complexation dynamics: Quantum chemistry calculation, molecular dynamics simulations the nature and dynamics of the phenol-benzene complex in the mixed solvent, benzene/CCl4. Under thermal used for the phenol-benzene interaction in the MD simulations is in good accord with the highest level

  17. Molecular Dynamics Simulations of Heat Transfer In Nanoscale Liquid Films

    E-Print Network [OSTI]

    Kim, Bo Hung

    2010-07-14T23:59:59.000Z

    Molecular Dynamics (MD) simulations of nano-scale flows typically utilize fixed lattice crystal interactions between the fluid and stationary wall molecules. This approach cannot properly model thermal interactions at the wall-fluid interface...

  18. Spatially Heterogeneous Dynamics and Dynamic Facilitation in a Model of Viscous Silica Michael Vogel* and Sharon C. Glotzer

    E-Print Network [OSTI]

    Weeks, Eric R.

    this behavior. The mode coupling theory [1] describes many aspects of dynamical behavior at high T- stood as a simple activated bondbreaking process. Here, we perform molecular dynamics (MD) simula- tionsSpatially Heterogeneous Dynamics and Dynamic Facilitation in a Model of Viscous Silica Michael

  19. Enhanced heat transfer through filler-polymer interface by surface-coupling agent in heat-dissipation material: A non-equilibrium molecular dynamics study

    SciTech Connect (OSTI)

    Tanaka, Kouichi [DENSO CORPORATION, Kariya, Aichi 448-8661 (Japan); Graduate School of Engineering, Nagoya Institute of Technology, Nagoya 466-8555 (Japan); Ogata, Shuji; Kobayashi, Ryo; Tamura, Tomoyuki [Graduate School of Engineering, Nagoya Institute of Technology, Nagoya 466-8555 (Japan); Kitsunezuka, Masashi; Shinma, Atsushi [DENSO CORPORATION, Kariya, Aichi 448-8661 (Japan)

    2013-11-21T23:59:59.000Z

    Developing a composite material of polymers and micrometer-sized fillers with higher heat conductance is crucial to realize modular packaging of electronic components at higher densities. Enhancement mechanisms of the heat conductance of the polymer-filler interfaces by adding the surface-coupling agent in such a polymer composite material are investigated through the non-equilibrium molecular dynamics (MD) simulation. A simulation system is composed of ?-alumina as the filler, bisphenol-A epoxy molecules as the polymers, and model molecules for the surface-coupling agent. The inter-atomic potential between the ?-alumina and surface-coupling molecule, which is essential in the present MD simulation, is constructed to reproduce the calculated energies with the electronic density-functional theory. Through the non-equilibrium MD simulation runs, we find that the thermal resistance at the interface decreases significantly by increasing either number or lengths of the surface-coupling molecules and that the effective thermal conductivity of the system approaches to the theoretical value corresponding to zero thermal-resistance at the interface. Detailed analyses about the atomic configurations and local temperatures around the interface are performed to identify heat-transfer routes through the interface.

  20. Department of Materials Science and Engineering University of Maryland, College Park, MD

    E-Print Network [OSTI]

    Rubloff, Gary W.

    for engineering practice #12;Topics Covered: I. Electrical and Optical Properties--Organic Photovoltaics A. Introduction: Organic photovoltaics B. Ohm's law C. Energy bands and energy gaps D. Carrier density in metals and semiconductors E. Optical absorption in semiconductors F. Excitons -- Size, Energy, Dynamics G. PN junction H

  1. DFT-MD approach to TiO2/liquid interface systems for photocatalysis and dye-sensitised solar cell

    E-Print Network [OSTI]

    Katsumoto, Shingo

    DFT-MD approach to TiO2/liquid interface systems for photocatalysis and dye-sensitised solar cell- namics (MD) analysis of TiO2/solution in- terfaces related to photocatalysis and dye- sensitized solar

  2. Dynamic

    Office of Legacy Management (LM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOn AprilA group currentBradleyTableSelling7111AWell: Gas productionDynamic , and Static ,

  3. Name Role Contact Thomas G Keens, M.D., C.I.P. Chair, Committee on Clinical Investigations tkeens@chla.usc.edu

    E-Print Network [OSTI]

    Valero-Cuevas, Francisco

    @chla.usc.edu (323) 3612265 Alan B. Lewis, M.D. Vice Chair, Committee on Clinical Investigations alewis Deirdre Anglin, MD ViceChair, IRB Email: anglin@usc.edu Phone: (323) 2232340 Robert Larsen, MD Vice

  4. Coupling MD Simulations and X-ray Absorption Spectroscopy to Study Ions in Solution

    SciTech Connect (OSTI)

    Marcos, E. Sanchez; Beret, E. C.; Martinez, J. M.; Pappalardo, R. R. [University of Seville, Dept. of Physical Chemistry (Spain); Ayala, R.; Munoz-Paez, A. [University of Seville, CSIC-ICMSE. Dept. of Inorganic Chemistry (Spain)

    2007-11-29T23:59:59.000Z

    The structure of ionic solutions is a key-point in understanding physicochemical properties of electrolyte solutions. Among the reduced number of experimental techniques which can supply direct information on the ion environment, X-ray Absorption techniques (XAS) have gained importance during the last decades although they are not free of difficulties associated to the data analysis leading to provide reliable structures. Computer simulations of ions in solution is a theoretical alternative to provide information on the solvation structure. Thus, the use of computational chemistry can increase the understanding of these systems although an accurate description of ionic solvation phenomena represents nowadays a significant challenge to theoretical chemistry. We present: (a) the assignment of features in the XANES spectrum to well defined structural motif in the ion environment, (b) MD-based evaluation of EXAFS parameters used in the fitting procedure to make easier the structural resolution, and (c) the use of the agreement between experimental and simulated XANES spectra to help in the choice of a given intermolecular potential for Computer Simulations. Chemical problems examined are: (a) the identification of the second hydration shell in dilute aqueous solutions of highly-charged cations, such as Cr{sup 3+}, Rh{sup 3+}, Ir{sup 3+}, (b) the invisibility by XAS of certain structures characterized by Computer Simulations but exhibiting high dynamical behavior and (c) the solvation of Br{sup -} in acetonitrile.

  5. Molecular Dynamics Simulation of Macromolecules Using Graphics Processing Unit

    E-Print Network [OSTI]

    Ji Xu; Ying Ren; Wei Ge; Xiang Yu; Xiaozhen Yang; Jinghai Li

    2010-01-21T23:59:59.000Z

    Molecular dynamics (MD) simulation is a powerful computational tool to study the behavior of macromolecular systems. But many simulations of this field are limited in spatial or temporal scale by the available computational resource. In recent years, graphics processing unit (GPU) provides unprecedented computational power for scientific applications. Many MD algorithms suit with the multithread nature of GPU. In this paper, MD algorithms for macromolecular systems that run entirely on GPU are presented. Compared to the MD simulation with free software GROMACS on a single CPU core, our codes achieve about 10 times speed-up on a single GPU. For validation, we have performed MD simulations of polymer crystallization on GPU, and the results observed perfectly agree with computations on CPU. Therefore, our single GPU codes have already provided an inexpensive alternative for macromolecular simulations on traditional CPU clusters and they can also be used as a basis to develop parallel GPU programs to further speedup the computations.

  6. Molecular Dynamics Simulations of Temperature Equilibration in Dense Hydrogen

    SciTech Connect (OSTI)

    Glosli, J; Graziani, F; More, R; Murillo, M; Streitz, F; Surh, M; Benedict, L; Hau-Riege, S; Langdon, A; London, R

    2008-02-14T23:59:59.000Z

    The temperature equilibration rate in dense hydrogen (for both T{sub i} > T{sub e} and T{sub i} < T{sub e}) has been calculated with large-scale molecular dynamics simulations for temperatures between 10 and 300 eV and densities between 10{sup 20}/cc to 10{sup 24}/cc. Careful attention has been devoted to convergence of the simulations, including the role of semiclassical potentials. We find that for Coulomb logarithms L {approx}> 1, Brown-Preston-Singleton [Brown et al., Phys. Rep. 410, 237 (2005)] with the sub-leading corrections and the fit of Gericke-Murillo-Schlanges [Gericke et al., PRE 65, 036418 (2003)] to the T-matrix evaluation of the collision operator, agrees with the MD data to within the error bars of the simulation. For more strongly-coupled plasmas where L {approx}< 1, our numerical results are consistent with the fit of Gericke-Murillo-Schlanges.

  7. Molecular Dynamics Simulations on High-Performance Reconfigurable

    E-Print Network [OSTI]

    Herbordt, Martin

    23 Molecular Dynamics Simulations on High-Performance Reconfigurable Computing Systems MATT CHIU. 2010. Molecular dynamics simulations on high performance recon- figurable computing systems. ACM Trans://doi.acm.org/10.1145/1862648.1862653. 1. INTRODUCTION Molecular dynamics simulation (MD) is a

  8. Vehicle Technologies Office Merit Review 2015: Cummins MD & HD Accessory Hybridization CRADA

    Broader source: Energy.gov [DOE]

    Presentation given by Oak Ridge National Laboratory at 2015 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about Cummins MD &...

  9. Vehicle Technologies Office Merit Review 2014: Cummins MD & HD Accessory Hybridization CRADA

    Broader source: Energy.gov [DOE]

    Presentation given by Oak Ridge National Laboratory at 2014 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about Cummins MD &...

  10. Andrea E. Reid, M.D., M.P.H. INFORMATION

    E-Print Network [OSTI]

    Goodrich, Lisa V.

    to practice State: District of Columbia License No: MD038392 Initial Date: 01/01/2011 Renewal/Expiration Date Providence, RI 02912 9/1980-6/1984 ScB with Honors, Psychology Medical Education: Harvard Medical School 25

  11. Intelligent Mobile Health Monitoring System (IMHMS) Rifat Shahriyar, Md. Faizul Bari, Gourab Kundu, Sheikh Iqbal Ahamed,

    E-Print Network [OSTI]

    Boutaba, Raouf

    , Sheikh Iqbal Ahamed, Md. Mostofa Akbar Department of Computer Science and Engineering, Bangladesh.com, sheikh.ahamed@mu.edu, mostofa@cse.buet.ac.bd Abstract. Health monitoring is repeatedly mentioned as one

  12. Catharine Whiteside, MD PhD Vice Provost, Relations with Health Care Institutions

    E-Print Network [OSTI]

    Zandstra, Peter W.

    Catharine Whiteside, MD PhD Dean Vice Provost, Relations with Health Care Institutions Office. Professor Andrews received her PhD from the University of Toronto and completed further training

  13. Spin dynamics simulation of electron spin relaxation in Ni{sup 2+}(aq)

    SciTech Connect (OSTI)

    Rantaharju, Jyrki, E-mail: jjrantaharju@gmail.com; Mareš, Ji?í, E-mail: jiri.mares@oulu.fi; Vaara, Juha, E-mail: juha.vaara@iki.fi [NMR Research Group, Department of Physics, University of Oulu, P.O. Box 3000, Oulu, FIN-90014 (Finland)

    2014-07-07T23:59:59.000Z

    The ability to quantitatively predict and analyze the rate of electron spin relaxation of open-shell systems is important for electron paramagnetic resonance and paramagnetic nuclear magnetic resonance spectroscopies. We present a combined molecular dynamics (MD), quantum chemistry (QC), and spin dynamics simulation method for calculating such spin relaxation rates. The method is based on the sampling of a MD trajectory by QC calculations, to produce instantaneous parameters of the spin Hamiltonian used, in turn, to numerically solve the Liouville-von Neumann equation for the time evolution of the spin density matrix. We demonstrate the approach by simulating the relaxation of electron spin in an aqueous solution of Ni{sup 2+} ion. The spin-lattice (T{sub 1}) and spin-spin (T{sub 2}) relaxation rates are extracted directly from the simulations of the time dependence of the longitudinal and transverse magnetization, respectively. Good agreement with the available, indirectly obtained experimental data is obtained by our method.

  14. Some recent efforts toward high density implosions

    SciTech Connect (OSTI)

    McClellan, G.E.

    1980-12-04T23:59:59.000Z

    Some recent Livermore efforts towards achieving high-density implosions are presented. The implosion dynamics necessary to compress DT fuel to 10 to 100 times liquid density are discussed. Methods of diagnosing the maximum DT density for a specific design are presented along with results to date. The dynamics of the double-shelled target with an exploding outer shell are described, and some preliminary experimental results are presented.

  15. Computational and Spectroscopic Investigations of the Molecular Scale Structure and Dynamics of Geologically Important Fluids and Mineral-Fluid Interfaces

    SciTech Connect (OSTI)

    R. James Kirkpatrick; Andrey G. Kalinichev

    2008-11-25T23:59:59.000Z

    Research supported by this grant focuses on molecular scale understanding of central issues related to the structure and dynamics of geochemically important fluids, fluid-mineral interfaces, and confined fluids using computational modeling and experimental methods. Molecular scale knowledge about fluid structure and dynamics, how these are affected by mineral surfaces and molecular-scale (nano-) confinement, and how water molecules and dissolved species interact with surfaces is essential to understanding the fundamental chemistry of a wide range of low-temperature geochemical processes, including sorption and geochemical transport. Our principal efforts are devoted to continued development of relevant computational approaches, application of these approaches to important geochemical questions, relevant NMR and other experimental studies, and application of computational modeling methods to understanding the experimental results. The combination of computational modeling and experimental approaches is proving highly effective in addressing otherwise intractable problems. In 2006-2007 we have significantly advanced in new, highly promising research directions along with completion of on-going projects and final publication of work completed in previous years. New computational directions are focusing on modeling proton exchange reactions in aqueous solutions using ab initio molecular dynamics (AIMD), metadynamics (MTD), and empirical valence bond (EVB) approaches. Proton exchange is critical to understanding the structure, dynamics, and reactivity at mineral-water interfaces and for oxy-ions in solution, but has traditionally been difficult to model with molecular dynamics (MD). Our ultimate objective is to develop this capability, because MD is much less computationally demanding than quantum-chemical approaches. We have also extended our previous MD simulations of metal binding to natural organic matter (NOM) to a much longer time scale (up to 10 ns) for significantly larger systems. These calculations have allowed us, for the first time, to study the effects of metal cations with different charges and charge density on the NOM aggregation in aqueous solutions. Other computational work has looked at the longer-time-scale dynamical behavior of aqueous species at mineral-water interfaces investigated simultaneously by NMR spectroscopy. Our experimental NMR studies have focused on understanding the structure and dynamics of water and dissolved species at mineral-water interfaces and in two-dimensional nano-confinement within clay interlayers. Combined NMR and MD study of H2O, Na+, and Cl- interactions with the surface of quartz has direct implications regarding interpretation of sum frequency vibrational spectroscopic experiments for this phase and will be an important reference for future studies. We also used NMR to examine the behavior of K+ and H2O in the interlayer and at the surfaces of the clay minerals hectorite and illite-rich illite-smectite. This the first time K+ dynamics has been characterized spectroscopically in geochemical systems. Preliminary experiments were also performed to evaluate the potential of 75As NMR as a probe of arsenic geochemical behavior. The 75As NMR study used advanced signal enhancement methods, introduced a new data acquisition approach to minimize the time investment in ultra-wide-line NMR experiments, and provides the first evidence of a strong relationship between the chemical shift and structural parameters for this experimentally challenging nucleus. We have also initiated a series of inelastic and quasi-elastic neutron scattering measurements of water dynamics in the interlayers of clays and layered double hydroxides. The objective of these experiments is to probe the correlations of water molecular motions in confined spaces over the scale of times and distances most directly comparable to our MD simulations and on a time scale different than that probed by NMR. This work is being done in collaboration with Drs. C.-K. Loong, N. de Souza, and A.I. Kolesnikov at the Intense Pulsed

  16. Subsystem Density-Functional Theory as an Effective Tool for Modeling Ground and Excited States, their Dynamics, and Many-Body Interactions

    E-Print Network [OSTI]

    Krishtal, Alisa; Genova, Alessandro; Pavanello, Michele

    2015-01-01T23:59:59.000Z

    Subsystem Density-Functional Theory (DFT) is an emerging technique for calculating the electronic structure of complex molecular and condensed phase systems. In this topical review, we focus on some recent advances in this field related to the computation of condensed phase systems, their excited states, and the evaluation of many-body interactions between the subsystems. As subsystem DFT is in principle an exact theory, any advance in this field can have a dual role. One is the possible applicability of a resulting method in practical calculations. The other is the possibility of shedding light on some quantum-mechanical phenomenon which is more easily treated by subdividing a supersystem into subsystems. An example of the latter is many-body interactions. In the discussion, we present some recent work from our research group as well as some new results, casting them in the current state-of-the-art in this review as comprehensively as possible.

  17. Phenomenological Relativistic Energy Density Functionals

    SciTech Connect (OSTI)

    Lalazissis, G. A.; Kartzikos, S. [Physics Department, Aristotle University of Thessaloniki (Greece); Niksic, T.; Paar, N.; Vretenar, D. [Physics Department, University of Zagreb (Croatia); Ring, P. [Physics Department, TU Muenchen, Garching (Germany)

    2009-08-26T23:59:59.000Z

    The framework of relativistic nuclear energy density functionals is applied to the description of a variety of nuclear structure phenomena, not only in spherical and deformed nuclei along the valley of beta-stability, but also in exotic systems with extreme isospin values and close to the particle drip-lines. Dynamical aspects of exotic nuclear structure is explored using the fully consistent quasiparticle random-phase approximation based on the relativistic Hartree-Bogoliubov model. Recent applications of energy density functionals with explicit density dependence of the meson-nucleon couplings are presented.

  18. MD/HD Advanced Technology Evaluations | Department of Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn't YourTransport(FactDepartment ofLetterEconomy andTermsDepartment1| Department ofEnergyFMCFC

  19. Towards Production FPGA-Accelerated Molecular Dynamics: Progress and Challenges

    E-Print Network [OSTI]

    Herbordt, Martin

    dynamics simulation has shown that including on-the-fly neighbor list calculation (particle filtering for this loss. I. INTRODUCTION Molecular dynamics simulation (MD) is a central method in high performance. Herbordt Computer Architecture and Automated Design Laboratory Department of Electrical and Computer

  20. Optical pumpterahertz probe spectroscopy of dyes in solutions: Probing the dynamics of liquid solvent or solid precipitate?

    E-Print Network [OSTI]

    KuÂ?el, Petr

    dynamics simulations to investigate ultrafast dynamics following electronic excitation of Coumarin 153 and dynamics, preferably at a molecular level of reso- lution. In particular, solvent relaxation following body of time-resolved spectro- scopic studies, as well as molecular dynamics MD simula- tions have been

  1. Molecular dynamics simulation of complex molecules at interfaces: dendritic surfactants in clay and amyloid peptides near lipid bilayers

    E-Print Network [OSTI]

    Han, Kunwoo

    2009-06-02T23:59:59.000Z

    We apply a molecular dynamics (MD) simulation technique to complex molecules at interfaces. Partitioning of dendritic surfactants into clay gallery and Ab protein behavior near hydrated lipids are chosen for the purpose. Using a full atomistic model...

  2. Mapping the energy and diffusion landscapes of membrane proteins at the cell surface using high-density single-molecule imaging and Bayesian inference: application to the multi-scale dynamics of glycine receptors in the neuronal membrane

    E-Print Network [OSTI]

    Masson, Jean-Baptiste; Salvatico, Charlotte; Renner, Marianne; Specht, Christian G; Triller, Antoine; Dahan, Maxime

    2015-01-01T23:59:59.000Z

    Protein mobility is conventionally analyzed in terms of an effective diffusion. Yet, this description often fails to properly distinguish and evaluate the physical parameters (such as the membrane friction) and the biochemical interactions governing the motion. Here, we present a method combining high-density single-molecule imaging and statistical inference to separately map the diffusion and energy landscapes of membrane proteins across the cell surface at ~100 nm resolution (with acquisition of a few minutes). When applying these analytical tools to glycine neurotransmitter receptors (GlyRs) at inhibitory synapses, we find that gephyrin scaffolds act as shallow energy traps (~3 kBT) for GlyRs, with a depth modulated by the biochemical properties of the receptor-gephyrin interaction loop. In turn, the inferred maps can be used to simulate the dynamics of proteins in the membrane, from the level of individual receptors to that of the population, and thereby, to model the stochastic fluctuations of physiologi...

  3. Molecular Dynamics Simulations of Shock-Induced Thermite Reaction Vikas Tomar1,a

    E-Print Network [OSTI]

    Tomar, Vikas

    Molecular Dynamics Simulations of Shock-Induced Thermite Reaction Vikas Tomar1,a and Min Zhou1,b 1 Dynamics, Thermite Mixture Abstract. A computational framework for molecular dynamics (MD) simulations of shock-induced reactions in thermite mixtures is developed. The system under study is an Fe2O3+Al

  4. Shell Model Dynamics of HCl on the MgO(001) Surface Terrace Andreas Markmann,1

    E-Print Network [OSTI]

    Markmann, Andreas

    are then used to aid the analysis of MD calculations. After equilibrium dynamics, a sudden excitation of the OH of molecular dynamics using specially tailored laser fields. The reaction of hydrogen chloride moleculesShell Model Dynamics of HCl on the MgO(001) Surface Terrace Andreas Markmann,1 Jacob L. Gavartin,2

  5. Dynamics of Different Hydrogen Classes in -lactoglobulin: A Quasielastic Neutron Scattering Investigation

    E-Print Network [OSTI]

    Tuscia, Università Degli Studi Della

    Dynamics of Different Hydrogen Classes in -lactoglobulin: A Quasielastic Neutron Scattering investigated by means of quasielastic neutron scattering. To discriminate the possibly different dynamical- thods,11-13 molecular dynamics (MD) simulations,14 X-ray crys- tallography,15 and neutron scattering.6

  6. HIV-1 Tat membrane interactions probed using X-ray and neutron scattering, CD spectroscopy and MD simulations

    E-Print Network [OSTI]

    Nagle, John F.

    HIV-1 Tat membrane interactions probed using X-ray and neutron scattering, CD spectroscopy and MD translocation, were provided by wide-angle X-ray scattering (WAXS) and neutron scattering. CD spectroscopy for Neutron Research, 100 Bureau Drive, Stop 6102, Gaithersburg, MD 20899, United States d CHESS, Cornell

  7. California Health eQuality Advisory Committee Kenneth W. Kizer, M.D., M.P.H. -Chair

    E-Print Network [OSTI]

    California at Davis, University of

    States, Inc. Thomas Williams, Dr.P.H., M.B.A. President and Chief Executive Officer Integrated Healthcare. Scott, M.D., M.P.H., Ex officio Chief Medical Information Officer California Department of Health CareCalifornia Health eQuality Advisory Committee Kenneth W. Kizer, M.D., M.P.H. - Chair Distinguished

  8. MARYLAND BIOTECHNOLOGY CENTER JOINS HOPKINS, UNIVERSITY OF MD IN AWARDING 2013 BIOMARYLAND LIFE PRIZE

    E-Print Network [OSTI]

    Weber, David J.

    PRIZE $50,000 grants help further research, bring new discoveries to commercial market BALTIMORE, MD will use the funding to develop technology that will aid in the safer delivery of radiation therapy to continue his research on a safer way to deliver radiation therapy." "This is a fantastic opportunity

  9. HOPKINS, UNIVERSITY OF MD, BALTIMORE FACULTY RESEARCHERS WIN 2014 BIOMARYLAND LIFE PRIZES

    E-Print Network [OSTI]

    Weber, David J.

    ,000 grants help further research, bring new discoveries to commercial market BALTIMORE, MD (February 19, 2014 for her development of a blood test for the early detection of pancreatic cancer. #12;The LIFE prize the funding to develop technology that will aid in the safer delivery of radiation therapy. Previous winners

  10. Ira Helfand, MD International Physicians for the Prevention of Nuclear War

    E-Print Network [OSTI]

    Robock, Alan

    Ira Helfand, MD International Physicians for the Prevention of Nuclear War Physicians for Social Responsibility NUCLEAR FAMINE: A BILLION PEOPLE AT RISK Global Impacts of Limited Nuclear War on Agriculture of studies have shown that a limited, regional nuclear war between India and Pakistan would cause significant

  11. Hot Water DJ: Saving Energy by Pre-mixing Hot Water Md Anindya Prodhan

    E-Print Network [OSTI]

    Whitehouse, Kamin

    Hot Water DJ: Saving Energy by Pre-mixing Hot Water Md Anindya Prodhan Department of Computer University of Virginia whitehouse@virginia.edu Abstract After space heating and cooling, water heating consumption. Current water heating systems waste up to 20% of their energy due to poor insulation in pipes

  12. Corbicula Active (ABM) Biomonitoring and Passive (POM) Chlordane Monitoring in the Anacostia River Watershed (MD).

    E-Print Network [OSTI]

    District of Columbia, University of the

    in the Anacostia River Watershed (MD). Final Report to the DC Water Resources Research Center Dr. Harriette L hydrocarbons (PAHs), 28 polychlorinated biphenyl congeners (PCBs), 6 Aroclors, 21 pesticides, and five metals (Cd, Cr, Cu, Fe, Pb) plus technical chlordane, percent water and percent lipid. This ABM study

  13. CityBizList US Green Building Council -MD Celebrating Move to

    E-Print Network [OSTI]

    CityBizList US Green Building Council - MD Celebrating Move to Hunt Valley Share Email this Article Baltimore County Executive Jim Smith will join the U.S. Green Building Council Maryland to celebrate Horst, Senior Vice President, U.S. Green Building Council. Horst has served as chair of USGBC's LEED

  14. Vendor Location PHS Assurance# A&G Pharmaceutical, Inc. MD A4404-01

    E-Print Network [OSTI]

    Bandettini, Peter A.

    BioScience Labs MD A3467-01 Alpha Genesis, Inc. SC A3645-01 Antibody Research Corporation MO A4489. On the BPA Program website open the current 'BPA Commodity List' and use the 'animal services', 'biological materials' or 'blood/blood products' tabs to search for these vendors. If a vendor is listed, the purchaser

  15. A coupled RISM/MD or MC simulation methodology for solvation free energies

    E-Print Network [OSTI]

    Truong, Thanh N.

    A coupled RISM/MD or MC simulation methodology for solvation free energies Holly Freedman, Thanh N methods for determination of solvation free energies. We employ the RISM formulation of solvation free-netted chain equations. We apply this approach to determining free energies of solvation for several small

  16. Limbic System Page 1 of 10 Srdjan D. Antic, M.D. Limbic system Emotional Experience

    E-Print Network [OSTI]

    Oliver, Douglas L.

    function. NMDA-dependent long-term potentiation is a cellular mechanism responsible for fear conditioning.M. is the most studied patient with Urbach-Wiethe disease. After a battery of tests, which included spiders Srdjan D. Antic, M.D. 3 as well as an appetitive (positive) conditioning. Individuals with larger

  17. The Centre for Blood Research Athan Kuliopulos, MD, PhD

    E-Print Network [OSTI]

    Strynadka, Natalie

    The Centre for Blood Research Athan Kuliopulos, MD, PhD Director, Hemostasis & Thrombosis coating blood vessel walls rupture and expose collagen, platelets spring into action to form a blood clot, according to the researchers. Compared to other diseases, blood clotting has been very well understood

  18. Advanced age remains an Achilles heel for liver resections. Laurent Sulpice, MD1,3

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    and Karim Boudjema, MD, PhD1,3 1- Service de Chirurgie Hépatobiliaire et Digestive. Centre Hospitalier, Centre Hospitalier Universitaire, Université de Rennes 1, Rennes, France Email : laurent in surgical techniques, perioperative management and postoperative care, LR has become increasingly common

  19. A survey on vehicular cloud computing Md Whaiduzzaman a,n

    E-Print Network [OSTI]

    Melbourne, University of

    A survey on vehicular cloud computing Md Whaiduzzaman a,n , Mehdi Sookhak a , Abdullah Gani a , Rajkumar Buyya b a Mobile Cloud Computing Research Lab, Faculty of Computer Science & Information control Intelligent transportation systems Cloud computing Vehicular cloud computing a b s t r a c

  20. Five-Year MD Enrichment Program Application/Plan University of Connecticut School of Medicine

    E-Print Network [OSTI]

    Oliver, Douglas L.

    Five-Year MD Enrichment Program Application/Plan University of Connecticut School of Medicine Full_________________________________ Proposed graduation date_________________________ Outline of enrichment plan: (specify date)____________ Please detail on a month-to- month basis your enrichment program (Be specific): Academic Year

  1. Semiclassical analysis of quantum dynamics

    E-Print Network [OSTI]

    Siyang Yang

    2011-11-15T23:59:59.000Z

    Simulating the molecular dynamics (MD) using classical or semi-classical trajectories provides important details for the understanding of many chemical reactions, protein folding, drug design, and solvation effects. MD simulations using trajectories have achieved great successes in the computer simulations of various systems, but it is difficult to incorporate quantum effects in a robust way. Therefore, improving quantum wavepacket dynamics and incorporating nonadiabatic transitions and quantum effects into classical and semi-classical molecular dynamics is critical as well as challenging. In this paper, we present a MD scheme in which a new set of equations of motion (EOM) are proposed to effectively propagate nuclear trajectories while conserving quantum mechanical energy which is critical for describing quantum effects like tunneling. The new quantum EOM is tested on a one-state one-dimensional and a two-state two-dimensional model nonadiabatic systems. The global quantum force experienced by each trajectory promotes energy redistribution among the bundle of trajectories, and thus helps the individual trajectory tunnel through the potential barrier higher than the energy of the trajectory itself. Construction of the new quantum force and EOM also provides a better way to treat the issue of back-reaction in mixed quantum-classical (MQC) methods, i.e. self-consistency between quantum degrees of freedom (DOF) and classical DOF.

  2. Coupled displacive and orderdisorder dynamics in LiNbO3 by molecular-dynamics simulation

    E-Print Network [OSTI]

    Gopalan, Venkatraman

    .1063/1.1669063 Ferroelectric lithium niobate (LiNbO3) has emerged as an important material in surface acoustic wave devices1 the structure and properties of materials. Indeed, atomic-level simulations have been used previously-dynamics MD simulations described here we treat the Coulomb interactions using a direct summation method

  3. Topics in Microeconometrics: Estimation of a Dynamic Model of Occupational Transitions, Wage and Non-Wage Benefits Cross Validation Bandwidth Selection for Derivatives of Various Dimensional Densities Testing the Additive Separability of the Teacher Value Added Effect Semiparametrically

    E-Print Network [OSTI]

    Baird, Matthew David

    2012-01-01T23:59:59.000Z

    115 3 Testing the Additive Separability of the Teacher ValueDensities Testing the Additive Separability of the TeacherDensities Testing the Additive Separability of the Teacher

  4. Density constrained TDHF

    E-Print Network [OSTI]

    Oberacker, V E

    2015-01-01T23:59:59.000Z

    In this manuscript we provide an outline of the numerical methods used in implementing the density constrained time-dependent Hartree-Fock (DC-TDHF) method and provide a few examples of its application to nuclear fusion. In this approach, dynamic microscopic calculations are carried out on a three-dimensional lattice and there are no adjustable parameters, the only input is the Skyrme effective NN interaction. After a review of the DC-TDHF theory and the numerical methods, we present results for heavy-ion potentials $V(R)$, coordinate-dependent mass parameters $M(R)$, and precompound excitation energies $E^{*}(R)$ for a variety of heavy-ion reactions. Using fusion barrier penetrabilities, we calculate total fusion cross sections $\\sigma(E_\\mathrm{c.m.})$ for reactions between both stable and neutron-rich nuclei. We also determine capture cross sections for hot fusion reactions leading to the formation of superheavy elements.

  5. Simulation studies of slow dynamics of hydration water in lysozyme : hydration level dependence and comparison with experiment using new time domain analysis

    E-Print Network [OSTI]

    Kim, Chansoo, S.M. Massachusetts Institute of Technology

    2008-01-01T23:59:59.000Z

    A series of Molecular Dynamics (MD) simulations using the GROMACS® package has been performed in this thesis. It is used to mimic and simulate the hydration water in Lysozyme with three different hydration levels (h = 0.3, ...

  6. Control-volume representation of molecular dynamics

    E-Print Network [OSTI]

    E. R. Smith; D. M. Heyes; D. Dini; T. A. Zaki

    2012-05-24T23:59:59.000Z

    A Molecular Dynamics (MD) parallel to the Control Volume (CV) formulation of fluid mechanics is developed by integrating the formulas of Irving and Kirkwood, J. Chem. Phys. 18, 817 (1950) over a finite cubic volume of molecular dimensions. The Lagrangian molecular system is expressed in terms of an Eulerian CV, which yields an equivalent to Reynolds' Transport Theorem for the discrete system. This approach casts the dynamics of the molecular system into a form that can be readily compared to the continuum equations. The MD equations of motion are reinterpreted in terms of a Lagrangian-to-Control-Volume (\\CV) conversion function $\\vartheta_{i}$, for each molecule $i$. The \\CV function and its spatial derivatives are used to express fluxes and relevant forces across the control surfaces. The relationship between the local pressures computed using the Volume Average (VA, Lutsko, J. Appl. Phys 64, 1152 (1988)) techniques and the Method of Planes (MOP, Todd et al, Phys. Rev. E 52, 1627 (1995)) emerges naturally from the treatment. Numerical experiments using the MD CV method are reported for equilibrium and non-equilibrium (start-up Couette flow) model liquids, which demonstrate the advantages of the formulation. The CV formulation of the MD is shown to be exactly conservative, and is therefore ideally suited to obtain macroscopic properties from a discrete system.

  7. MD 715

    National Nuclear Security Administration (NNSA)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOn AprilA Approved:Administration SandiaAdministration NewsAdministrator6 Page. S

  8. Molecular dynamics simulations of the elastic properties of polymer/carbon nanotube composites

    E-Print Network [OSTI]

    Elliott, James

    Molecular dynamics simulations of the elastic properties of polymer/carbon nanotube composites Yue composite. However, improvements in properties are by no means guaranteed, and the results are often in the composite. In this paper, we present classical molecular dynamics (MD) simulations of model polymer

  9. Molecular dynamics simulations of the nano-scale room-temperature oxidation of aluminum single crystals

    E-Print Network [OSTI]

    Southern California, University of

    films that form on aluminum and aluminum alloys in air protect the surface against further oxidationMolecular dynamics simulations of the nano-scale room-temperature oxidation of aluminum single Abstract The oxidation of aluminum single crystals is studied using molecular dynamics (MD) simulations

  10. A continuum-atomistic method for incorporating Joule heating into classical molecular dynamics simulations

    E-Print Network [OSTI]

    Brenner, Donald W.

    binding electronic structure calculations, pertur- bation models, and quantum-classical Hamiltonians [6 depends on the degree of approximation used in solving the electronic structure problem, which can add-scale molecular dynamics (MD) simulation is not to model electron dynamics, but rather to numerically solve

  11. Rotational Relaxation of Ionic Molecules in Electrolyte Solutions. Anisotropy Relaxation and Molecular Dynamics Study

    E-Print Network [OSTI]

    Kurnikova, Maria

    and the metal cation. Conductivity measure- ments and ab initio electronic structure calculations are used structure and the solute dynamics occur for ionic solute molecules. Both experimental4-10 and theoretical11 of experimental studies, ab initio electronic struc- ture, and molecular dynamics (MD) simulation is used

  12. EFFICIENT PARTICLE-PAIR FILTERING FOR ACCELERATION OF MOLECULAR DYNAMICS SIMULATION

    E-Print Network [OSTI]

    Herbordt, Martin

    EFFICIENT PARTICLE-PAIR FILTERING FOR ACCELERATION OF MOLECULAR DYNAMICS SIMULATION Matt Chiu ABSTRACT The acceleration of molecular dynamics (MD) simulations using high performance reconfigurable: determining the short-range force between particle pairs. In particular, we present the first FPGA study

  13. Glassy dynamics, aging in mobility, and structural relaxation of strongly adsorbed polymer films: Corrugation or confinement?

    E-Print Network [OSTI]

    Mueser, Martin

    Glassy dynamics, aging in mobility, and structural relaxation of strongly adsorbed polymer films of Western Ontario, London, Ontario N6A 5B7, Canada Abstract. A molecular dynamics simulation (MD. The model reproduces many experimentally observed features such as logarithmic aging of structural

  14. Geometry and Nanolength Scales versus Interface Interactions: Water Dynamics in AOT Lamellar Structures and

    E-Print Network [OSTI]

    Fayer, Michael D.

    occur in the water structure and dynamics. At the same time, MD simulations have shown that the mostGeometry and Nanolength Scales versus Interface Interactions: Water Dynamics in AOT Lamellar Structures and Reverse Micelles David E. Moilanen, Emily E. Fenn, Daryl Wong, and M. D. Fayer* Department

  15. Y. Gu, T. VanCourt, M.C. Herbordt / Proc. IEEE Conf. on Field Programmable Logic and Applications (2005) 1 ACCELERATING MOLECULAR DYNAMICS SIMULATIONS

    E-Print Network [OSTI]

    Herbordt, Martin

    2005-01-01T23:59:59.000Z

    (2005) 1 ACCELERATING MOLECULAR DYNAMICS SIMULATIONS WITH CONFIGURABLE CIRCUITS Yongfeng Gu Tom Van-space parameter for MD practitioners. 2. MOLECULAR DYNAMICS OVERVIEW Molecular Dynamics simulations generallyCourt Martin C. Herbordt Department of Electrical and Computer Engineering Boston University, Boston, MA 02215

  16. DOE - Office of Legacy Management -- Max Zuckerman and Sons Inc - MD 04

    Office of Legacy Management (LM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOn AprilA group currentBradleyTable ofArizonaBuffaloJohns0-04Maryland DisposalInc - MD

  17. Adding quantum effects to the semi-classical molecular dynamics simulations

    E-Print Network [OSTI]

    Yang, Siyang

    2011-01-01T23:59:59.000Z

    Simulating the molecular dynamics (MD) using classical or semi-classical trajectories provides important details for the understanding of many chemical reactions, protein folding, drug design, and solvation effects. MD simulations using trajectories have achieved great successes in the computer simulations of various systems, but it is difficult to incorporate quantum effects in a robust way. Therefore, improving quantum wavepacket dynamics and incorporating nonadiabatic transitions and quantum effects into classical and semi-classical molecular dynamics is critical as well as challenging. In this paper, we present a MD scheme in which a new set of equations of motion (EOM) are proposed to effectively propagate nuclear trajectories while conserving quantum mechanical energy which is critical for describing quantum effects like tunneling. The new quantum EOM is tested on a one-state one-dimensional and a two-state two-dimensional model nonadiabatic systems. The global quantum force experienced by each trajecto...

  18. Pair densities in density functional theory

    E-Print Network [OSTI]

    Chen, Huajie

    2015-01-01T23:59:59.000Z

    The exact interaction energy of a many-electron system is determined by the electron pair density, which is not well-approximated in standard Kohn-Sham density functional models. Here we study the (complicated but well-defined) exact universal map from density to pair density. We show that many common functionals, including the most basic version of the LDA (Dirac exchange with no correlation contribution), arise from particular approximations of this map. We develop an algorithm to compute the map numerically, and apply it to one-parameter families {a*rho(a*x)} of one-dimensional homogeneous and inhomogeneous single-particle densities. We observe that the pair density develops remarkable multiscale patterns which strongly depend on both the particle number and the "width" 1/a of the single-particle density. The simulation results are confirmed by rigorous asymptotic results in the limiting regimes a>>1 and a<<1. For one-dimensional homogeneous systems, we show that the whole spectrum of patterns is rep...

  19. Mapping densities in a noisy state space

    E-Print Network [OSTI]

    Domenico Lippolis

    2013-03-05T23:59:59.000Z

    Weak noise smooths out fractals in a chaotic state space and introduces a maximum attainable resolution to its structure. The balance of noise and deterministic stretching/contraction in each neighborhood introduces local invariants of the dynamics that can be used to partition the state space. We study the local discrete-time evolution of a density in a two-dimensional hyperbolic state space, and use the asymptotic eigenfunctions for the noisy dynamics to formulate a new state space partition algorithm.

  20. Equation for liquid density

    SciTech Connect (OSTI)

    Yaws, C.L.; Yang, H.C.; Hopper, J.R.; Cawley, W.A. (Lamar Univ., Beaumont, TX (US))

    1991-01-01T23:59:59.000Z

    Saturated liquid densities for organic chemicals are given as functions of temperature using a modified Rackett equation.

  1. Instabilities in the Nuclear Energy Density Functional

    E-Print Network [OSTI]

    M. Kortelainen; T. Lesinski

    2010-02-05T23:59:59.000Z

    In the field of Energy Density Functionals (EDF) used in nuclear structure and dynamics, one of the unsolved issues is the stability of the functional. Numerical issues aside, some EDFs are unstable with respect to particular perturbations of the nuclear ground-state density. The aim of this contribution is to raise questions about the origin and nature of these instabilities, the techniques used to diagnose and prevent them, and the domain of density functions in which one should expect a nuclear EDF to be stable.

  2. Effects of electron structure and multielectron dynamical response on strong-field multiphoton ionization of diatomic molecules with arbitrary orientation: An all-electron time-dependent density-functional-theory approach

    E-Print Network [OSTI]

    Chu, Shih-I; Telnov, Dmitry A.

    2009-04-03T23:59:59.000Z

    We present a time-dependent density-functional-theory approach for the ab initio study of the effect of correlated multielectron responses on the multiphoton ionization (MPI) of diatomic molecules N2, O2, and F2 in intense ...

  3. Coarse-Grained Molecular Dynamics Simulations of Depletion-Induced Interactions for Soft Matter Systems

    E-Print Network [OSTI]

    Tyler N. Shendruk; Martin Bertrand; James L. Harden; Gary W. Slater; Hendrick W. de Haan

    2014-08-01T23:59:59.000Z

    Given the ubiquity of depletion effects in biological and other soft matter systems, it is desirable to have coarse-grained Molecular Dynamics simulation approaches appropriate for the study of complex systems. This paper examines the use of two common truncated Lennard-Jones (WCA) potentials to describe a pair of colloidal particles in a thermal bath of depletants. The shifted-WCA model is the steeper of the two repulsive potentials considered, while the combinatorial-WCA model is the softer. It is found that the depletion-induced well depth for the combinatorial-WCA model is significantly deeper than the shifted-WCA model because the resulting overlap of the colloids yields extra accessible volume for depletants. For both shifted- and combinatorial-WCA simulations, the second virial coefficients and pair potentials between colloids are demonstrated to be well approximated by the Morphometric Thermodynamics (MT) model. This agreement suggests that the presence of depletants can be accurately modelled in MD simulations by implicitly including them through simple, analytical MT forms for depletion-induced interactions. Although both WCA potentials are found to be effective generic coarse-grained simulation approaches for studying depletion effects in complicated soft matter systems, combinatorial-WCA is the more efficient approach as depletion effects are enhanced at lower depletant densities. The findings indicate that for soft matter systems that are better modelled by potentials with some compressibility, predictions from hard-sphere systems could greatly underestimate the magnitude of depletion effects at a given depletant density.

  4. Modeling ramp compression experiments using large-scale molecular dynamics simulation.

    SciTech Connect (OSTI)

    Mattsson, Thomas Kjell Rene; Desjarlais, Michael Paul; Grest, Gary Stephen; Templeton, Jeremy Alan; Thompson, Aidan Patrick; Jones, Reese E.; Zimmerman, Jonathan A.; Baskes, Michael I. (University of California, San Diego); Winey, J. Michael (Washington State University); Gupta, Yogendra Mohan (Washington State University); Lane, J. Matthew D.; Ditmire, Todd (University of Texas at Austin); Quevedo, Hernan J. (University of Texas at Austin)

    2011-10-01T23:59:59.000Z

    Molecular dynamics simulation (MD) is an invaluable tool for studying problems sensitive to atomscale physics such as structural transitions, discontinuous interfaces, non-equilibrium dynamics, and elastic-plastic deformation. In order to apply this method to modeling of ramp-compression experiments, several challenges must be overcome: accuracy of interatomic potentials, length- and time-scales, and extraction of continuum quantities. We have completed a 3 year LDRD project with the goal of developing molecular dynamics simulation capabilities for modeling the response of materials to ramp compression. The techniques we have developed fall in to three categories (i) molecular dynamics methods (ii) interatomic potentials (iii) calculation of continuum variables. Highlights include the development of an accurate interatomic potential describing shock-melting of Beryllium, a scaling technique for modeling slow ramp compression experiments using fast ramp MD simulations, and a technique for extracting plastic strain from MD simulations. All of these methods have been implemented in Sandia's LAMMPS MD code, ensuring their widespread availability to dynamic materials research at Sandia and elsewhere.

  5. The evaluation within the development and deployment of IMS LD-based didactic materials: The MD2 + runtime adaptation approach

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    The evaluation within the development and deployment of IMS LD-based didactic materials: The MD2 in the didactic materials creation since it allows developers to check if the features of created material satisfy]. They have been applied to asses IMS LD based didactic material in conjunction with the experience provided

  6. FRAppE: Detecting Malicious Facebook Applications Md Sazzadur Rahman, Ting-Kai Huang, Harsha V. Madhyastha, and Michalis Faloutsos

    E-Print Network [OSTI]

    Madhyastha, Harsha V.

    FRAppE: Detecting Malicious Facebook Applications Md Sazzadur Rahman, Ting-Kai Huang, Harsha V for the popularity and addictiveness of Facebook. Unfortu- nately, hackers have realized the potential of using apps and campaigns. In this paper, we ask the question: given a Facebook application, can we determine

  7. Alamethicin in lipid bilayers: Combined use of X-ray scattering and MD simulations Jianjun Pan a

    E-Print Network [OSTI]

    Nagle, John F.

    Alamethicin in lipid bilayers: Combined use of X-ray scattering and MD simulations Jianjun Pan of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA d Canadian Neutron Beam Centre:1PC with varying amounts of alamethicin (Alm). We combine the use of X-ray diffuse scattering

  8. Lung mast cells are a source of secreted phospholipases A2 Massimo Triggiani, MD, PhD,a

    E-Print Network [OSTI]

    Gelb, Michael

    Lung mast cells are a source of secreted phospholipases A2 Massimo Triggiani, MD, PhD,a Giorgio and to examine the expression and release of sPLA2s from primary human lung mast cells (HLMCs). Methods: sPLA2 of asthmatic patients. (J Allergy Clin Immunol 2009;124:558-65.) Key words: Lung mast cells, secreted

  9. Second Order Co-occurrence PMI for Determining the Semantic Similarity of Md. Aminul Islam and Diana Inkpen

    E-Print Network [OSTI]

    Inkpen, Diana

    Second Order Co-occurrence PMI for Determining the Semantic Similarity of Words Md. Aminul Islam for calculating the semantic similarity of two target words. Our method, called Second Order Co-occurrence PMI (SOC-PMI), uses Pointwise Mutual Information to sort lists of important neighbor words of the two

  10. Survival in Academy AwardWinning Actors and Actresses Donald A. Redelmeier, MD, and Sheldon M. Singh, BSc

    E-Print Network [OSTI]

    Reid, Nancy

    Survival in Academy Award­Winning Actors and Actresses Donald A. Redelmeier, MD, and Sheldon M in status from winning an academy award is associated with long-term mortality among actors and actresses. Design: Retrospective cohort analysis. Setting: Academy of Motion Picture Arts and Sciences. Participants

  11. Surface Tensions in NaCl-Water-Air Systems from MD Simulations Ranjit Bahadur, Lynn M. Russell,*, and Saman Alavi

    E-Print Network [OSTI]

    Russell, Lynn

    Surface Tensions in NaCl-Water-Air Systems from MD Simulations Ranjit Bahadur, Lynn M. Russell, Ottawa, Ontario K1A 0R6, Canada ReceiVed: July 9, 2007; In Final Form: July 30, 2007 Surface tensions to the surface tension, while the energy-integral and test area methods provide direct estimates. At 1 atm

  12. Density-dependent covariant energy density functionals

    SciTech Connect (OSTI)

    Lalazissis, G. A. [Physics Department, Aristotle University of Thessaloniki, GR-54124 (Greece)

    2012-10-20T23:59:59.000Z

    Relativistic nuclear energy density functionals are applied to the description of a variety of nuclear structure phenomena at and away fromstability line. Isoscalar monopole, isovector dipole and isoscalar quadrupole giant resonances are calculated using fully self-consistent relativistic quasiparticle randomphase approximation, based on the relativistic Hartree-Bogoliubovmodel. The impact of pairing correlations on the fission barriers in heavy and superheavy nuclei is examined. The role of pion in constructing desnity functionals is also investigated.

  13. An Analysis of the Interactions between the Sem-5 SH3 Domain and Its Ligands Using Molecular Dynamics, Free Energy Calculations,

    E-Print Network [OSTI]

    Wang, Wei

    to the construction of van der Waals interaction energy profiles for each ligand as well as for wild-type and mutant Dynamics, Free Energy Calculations, and Sequence Analysis Wei Wang, Wendell A. Lim,, Araz Jakalian,§,# Jian the interactions between Sem-5 and its ligands using molecular dynamics (MD), free energy calculations

  14. 9/28/98 9:58:58 am, Journal of Non-Crystalline Solids MOLECULAR DYNAMICS SIMULATION OF VITREOUS SILICA STRUCTURES

    E-Print Network [OSTI]

    Goddard III, William A.

    Dynamics (MD) techniques to simulate glass structures has become a valuable tool for gaining insight1 9/28/98 9:58:58 am, Journal of Non-Crystalline Solids MOLECULAR DYNAMICS SIMULATION OF VITREOUS SILICA STRUCTURES Norman T. Huff*, Owens Corning Science and Technology Center, 2790 Columbus Road

  15. Molecular dynamics simulations of gold-catalyzed growth of silicon bulk crystals and nanowires

    E-Print Network [OSTI]

    Cai, Wei

    ARTICLES Molecular dynamics simulations of gold-catalyzed growth of silicon bulk crystals of the orientation, yield, and quality of the NWs. Much of the studies on the VLS growth mechanism have been focused. In this article, we present the first set of MD simu- lations of NW growth using this Au­Si potential model

  16. Kinetic energy deficit in the symmetric fission of /sup 259/Md. [Light particle emission in /sup 256/Fm fission

    SciTech Connect (OSTI)

    Hulet, E.K.; Wild, J.F.; Lougheed, R.W.; Baisden, P.A.; Dougan, R.J.; Mustafa, M.G.

    1980-10-01T23:59:59.000Z

    The fragment energies of about 725 coincidence events have now been observed in the spontaneous fission (SF) decay of 105-min /sup 259/Md since its discovery in 1977. The fission of /sup 259/Md is characterized by a symmetric mass distribution, similar to those of /sup 258/Fm and /sup 259/Fm, but with a broad total kinetic energy (anti TKE) distribution which peaks at about 195 MeV, in contrast to those of /sup 258/Fm and /sup 259/Fm, for which the anti TKE is about 240 MeV. This kinetic energy deficit, approx. 40 MeV, has been postulated to be due to the emission of hydrogen-like particles by /sup 259/Md at the scission point in a large fraction of the fissions, leaving the residual fissioning nucleus with 100 protons. The residual nucleus would then be able to divide into two ultrastable tin-like fission fragments, but with less kinetic energy than that observed in the SF of /sup 258/Fm and /sup 259/Fm, because of binding-energy losses and a reduction in the Coulomb repulsion of the major fragments. To test this hypothesis, counter-telescope experiments aimed at detecting and identifying these light particles were performed. In 439 SF events 3 + 3 protons of the appropriate energy were observed, too few to account for the kinetic energy deficit in the fission of /sup 259/Md. There seems to be no explanation for this problem within the framework of current fission theory. These results are discussed along with preliminary measurements of light-particle emission in the SF of /sup 256/Fm. 5 figures.

  17. High density matter

    E-Print Network [OSTI]

    J. R. Stone

    2013-02-11T23:59:59.000Z

    The microscopic composition and properties of matter at super-saturation densities have been the subject of intense investigation for decades. The scarcity of experimental and observational data has lead to the necessary reliance on theoretical models. However, there remains great uncertainty in these models, which, of necessity, have to go beyond the over-simple assumption that high density matter consists only of nucleons and leptons. Heavy strange baryons, mesons and quark matter in different forms and phases have to be included to fulfil basic requirements of fundamental laws of physics. In this review the latest developments in construction of the Equation of State (EoS) of high-density matter at zero and finite temperature assuming different composition of the matter are surveyed. Critical comparison of model EoS with available observational data on neutron stars, including gravitational masses, radii and cooling patterns is presented. The effect of changing rotational frequency on the composition of neutron stars during their lifetime is demonstrated. Compatibility of EoS of high-density, low temperature compact objects and low density, high temperature matter created in heavy-ion collisions is discussed.

  18. Density Matrix Topological Insulators

    E-Print Network [OSTI]

    A. Rivas; O. Viyuela; M. A. Martin-Delgado

    2013-10-31T23:59:59.000Z

    Thermal noise can destroy topological insulators (TI). However we demonstrate how TIs can be made stable in dissipative systems. To that aim, we introduce the notion of band Liouvillian as the dissipative counterpart of band Hamiltonian, and show a method to evaluate the topological order of its steady state. This is based on a generalization of the Chern number valid for general mixed states (referred to as density matrix Chern value), which witnesses topological order in a system coupled to external noise. Additionally, we study its relation with the electrical conductivity at finite temperature, which is not a topological property. Nonetheless, the density matrix Chern value represents the part of the conductivity which is topological due to the presence of quantum mixed edge states at finite temperature. To make our formalism concrete, we apply these concepts to the two-dimensional Haldane model in the presence of thermal dissipation, but our results hold for arbitrary dimensions and density matrices.

  19. portal: Libraries and the Academy, Vol. 9, No. 2 (2009), pp. 273286. Copyright 2009 by The Johns Hopkins University Press, Baltimore, MD 21218.

    E-Print Network [OSTI]

    Oakleaf, Megan

    2009-01-01T23:59:59.000Z

    by The Johns Hopkins University Press, Baltimore, MD 21218. INFORMATION STANDARDS Guiding Questions the information literacy assessments that best fit their needs. #12;Guiding Questions forAssessing Information

  20. Multiple density layered insulator

    DOE Patents [OSTI]

    Alger, Terry W. (Tracy, CA)

    1994-01-01T23:59:59.000Z

    A multiple density layered insulator for use with a laser is disclosed wh provides at least two different insulation materials for a laser discharge tube, where the two insulation materials have different thermoconductivities. The multiple layer insulation materials provide for improved thermoconductivity capability for improved laser operation.

  1. Multiple density layered insulator

    DOE Patents [OSTI]

    Alger, T.W.

    1994-09-06T23:59:59.000Z

    A multiple density layered insulator for use with a laser is disclosed which provides at least two different insulation materials for a laser discharge tube, where the two insulation materials have different thermoconductivities. The multiple layer insulation materials provide for improved thermoconductivity capability for improved laser operation. 4 figs.

  2. Energy in density gradient

    E-Print Network [OSTI]

    Vranjes, J

    2015-01-01T23:59:59.000Z

    Inhomogeneous plasmas and fluids contain energy stored in inhomogeneity and they naturally tend to relax into lower energy states by developing instabilities or by diffusion. But the actual amount of energy in such inhomogeneities has remained unknown. In the present work the amount of energy stored in a density gradient is calculated for several specific density profiles in a cylindric configuration. This is of practical importance for drift wave instability in various plasmas, and in particular in its application in models dealing with the heating of solar corona because the instability is accompanied with stochastic heating, so the energy contained in inhomogeneity is effectively transformed into heat. It is shown that even for a rather moderate increase of the density at the axis in magnetic structures in the corona by a factor 1.5 or 3, the amount of excess energy per unit volume stored in such a density gradient becomes several orders of magnitude greater than the amount of total energy losses per unit ...

  3. Dynamical simulation of heavy-ion collisions in the energy range from a few tens MeV/A to a few hundreds MeV/A

    E-Print Network [OSTI]

    M. V. Garzelli

    2008-10-13T23:59:59.000Z

    The overlapping stage of heavy-ion reactions can be simulated by dynamical microscopical models, such as those built on the basis of the Molecular Dynamics (MD) approaches, allowing to study the fragment formation process. The present performances of the Quantum MD (QMD) code developed at the University of Milano are discussed, showing results concerning fragment and particle production at bombarding energies up to $\\lsim$ 700 MeV/A, as well as a preliminary analysis on the isoscaling behaviour of isotopic yield ratios for reactions with isospin composition N/Z in the (1 - 1.2) range, at a 45 MeV/A bombarding energy.

  4. Traffic Dynamic Instability

    E-Print Network [OSTI]

    Louis Reese; Anna Melbinger; Erwin Frey

    2015-05-05T23:59:59.000Z

    Here we study a driven lattice gas model for microtubule depolymerizing molecular motors, where traffic jams of motors induce stochastic switching between microtubule growth and shrinkage. We term this phenomenon \\enquote{traffic dynamic instability} because it is reminiscent of microtubule dynamic instability [T. Mitchison and M. Kirschner, Nature 312, 237 (1984)]. The intermittent dynamics of growth and shrinking emerges from the interplay between the arrival of motors at the microtubule tip, motor induced depolymerization, and motor detachment from the tip. The switching dynamics correlates with low and high motor density on the lattice. This leads to an effectively bistable particle density in the system. A refined domain wall theory predicts this transient appearance of different phases in the system. The theoretical results are supported by stochastic simulations.

  5. Traffic Dynamic Instability

    E-Print Network [OSTI]

    Reese, Louis; Frey, Erwin

    2015-01-01T23:59:59.000Z

    Here we study a driven lattice gas model for microtubule depolymerizing molecular motors, where traffic jams of motors induce stochastic switching between microtubule growth and shrinkage. We term this phenomenon \\enquote{traffic dynamic instability} because it is reminiscent of microtubule dynamic instability [T. Mitchison and M. Kirschner, Nature 312, 237 (1984)]. The intermittent dynamics of growth and shrinking emerges from the interplay between the arrival of motors at the microtubule tip, motor induced depolymerization, and motor detachment from the tip. The switching dynamics correlates with low and high motor density on the lattice. This leads to an effectively bistable particle density in the system. A refined domain wall theory predicts this transient appearance of different phases in the system. The theoretical results are supported by stochastic simulations.

  6. On an open question about the complexity of a dynamic spectrum ...

    E-Print Network [OSTI]

    2014-12-02T23:59:59.000Z

    the users dynamically adjust their transmit power spectral densities over it. ... the performance of the whole system, a Dynamic Spectrum Management (DSM).

  7. Trillion-atom molecular dynamics becomes a reality

    SciTech Connect (OSTI)

    Kadau, Kai [Los Alamos National Laboratory; Germann, Timothy C [Los Alamos National Laboratory

    2008-01-01T23:59:59.000Z

    By utilizing the molecular dynamics code SPaSM on Livermore's BlueGene/L architecture, consisting of 212 992 IBM PowerPC440 700 MHz processors, a molecular dynamics simulation was run with one trillion atoms. To demonstrate the practicality and future potential of such ultra large-scale simulations, the onset of the mechanical shear instability occurring in a system of Lennard-Jones particles arranged in a simple cubic lattice was simulated. The evolution of the instability was analyzed on-the-fly using the in-house developed massively parallel graphical object-rendering code MD{_}render.

  8. Kinetics of Surface Enrichment: A Molecular Dynamics Study

    E-Print Network [OSTI]

    Prabhat K. Jaiswal; Sanjay Puri; Subir K. Das

    2010-11-29T23:59:59.000Z

    We use molecular dynamics (MD) to study the kinetics of surface enrichment (SE) in a stable homogeneous mixture (AB), placed in contact with a surface which preferentially attracts A. The SE profiles show a characteristic double-exponential behavior with two length scales: \\xi_-, which rapidly saturates to its equilibrium value, and \\xi_+, which diverges as a power-law with time (\\xi_+ \\sim t^\\theta). We find that hydrodynamic effects result in a crossover of the growth exponent from \\theta \\simeq 0.5 to \\theta \\simeq 1.0. There is also a corresponding crossover in the growth dynamics of the SE-layer thickness.

  9. High Energy Density Capacitors

    SciTech Connect (OSTI)

    None

    2010-07-01T23:59:59.000Z

    BEEST Project: Recapping is developing a capacitor that could rival the energy storage potential and price of today’s best EV batteries. When power is needed, the capacitor rapidly releases its stored energy, similar to lightning being discharged from a cloud. Capacitors are an ideal substitute for batteries if their energy storage capacity can be improved. Recapping is addressing storage capacity by experimenting with the material that separates the positive and negative electrodes of its capacitors. These separators could significantly improve the energy density of electrochemical devices.

  10. Gluon density in nuclei

    SciTech Connect (OSTI)

    Ayala, A.L. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Inst. de Fisica][Pelotas Univ., RS (Brazil). Inst. de Fisica e Matematica; Ducati, M.B.G. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Inst. de Fisica; Levin, E.M. [Fermi National Accelerator Lab., Batavia, IL (United States)][Nuclear Physics Inst., St. Petersburg (Russian Federation)

    1996-10-01T23:59:59.000Z

    In this talk we present our detailed study (theory and numbers) on the shadowing corrections to the gluon structure functions for nuclei. Starting from rather controversial information on the nucleon structure function which is originated by the recent HERA data, we develop the Glauber approach for the gluon density in a nucleus based on Mueller formula and estimate the value of the shadowing corrections in this case. Then we calculate the first corrections to the Glauber approach and show that these corrections are big. Based on this practical observation we suggest the new evolution equation which takes into account the shadowing corrections and solve it. We hope to convince you that the new evolution equation gives a good theoretical tool to treat the shadowing corrections for the gluons density in a nucleus and, therefore, it is able to provide the theoretically reliable initial conditions for the time evolution of the nucleus-nucleus cascade. The initial conditions should be fixed both theoretically and phenomenologically before to attack such complicated problems as the mixture of hard and soft processes in nucleus-nucleus interactions at high energy or the theoretically reliable approach to hadron or/and parton cascades for high energy nucleus-nucleus interaction. 35 refs., 24 figs., 1 tab.

  11. Holographic energy density in the Brans-Dicke teory

    E-Print Network [OSTI]

    Hungsoo Kim; H. W. Lee; Y. S. Myung

    2005-01-15T23:59:59.000Z

    We study cosmological applications of the holographic energy density. Considering the holographic energy density as a dynamical cosmological constant, we need the Brans-Dicke theory as a dynamical framework instead of general relativity. In this case we use the Bianchi identity as a consistency relation to obtain physical solutions. It is shown that the future event horizon as the IR cutoff provides the dark energy in the Brans-Dicke theory. Furthermore the role of the Brans-Dicke scalar is clarified in the dark energy-dominated universe by calculating its equation of state.

  12. Simulations of liquid ribidium expanded to the critical density

    SciTech Connect (OSTI)

    Ross, M; Yang, L H; Pilgrim, W

    2006-05-16T23:59:59.000Z

    Quantum molecular dynamic simulations were used to examine the change in atomic and electronic structure in liquid rubidium along its liquid-vapor coexistence curve. Starting from the liquid at the triple point, with increasing expansion we observe a continuous increase in the electron localization leading to ion clustering near the metal-nonmetal transition at about twice the critical density, in agreement with electrical measurements, and to the presence of dimers near and below the critical density.

  13. Low density microcellular foams

    DOE Patents [OSTI]

    LeMay, James D. (Castro Valley, CA)

    1991-01-01T23:59:59.000Z

    Disclosed is a process of producing microcellular foam which comprises the steps of: (a) selecting a multifunctional epoxy oligomer resin; (b) mixing said epoxy resin with a non-reactive diluent to form a resin-diluent mixture; (c) forming a diluent containing cross-linked epoxy gel from said resin-diluent mixture; (d) replacing said diluent with a solvent therefore; (e) replacing said solvent with liquid carbon dioxide; and (f) vaporizing off said liquid carbon dioxide under supercritical conditions, whereby a foam having a density in the range of 35-150 mg/cc and cell diameters less than about 1 .mu.m is produced. Also disclosed are the foams produced by the process.

  14. Low density microcellular foams

    DOE Patents [OSTI]

    LeMay, James D. (Castro Valley, CA)

    1992-01-01T23:59:59.000Z

    Disclosed is a process of producing microcellular from which comprises the steps of: (a) selecting a multifunctional epoxy oligomer resin; (b) mixing said epoxy resin with a non-reactive diluent to form a resin-diluent mixture; (c) forming a diluent containing cross-linked epoxy gel from said resin-diluent mixture; (d) replacing said diluent with a solvent therefore; (e) replacing said solvent with liquid carbon dioxide; and (f) vaporizing off said liquid carbon dioxide under supercritical conditions, whereby a foam having a density in the range of 35-150 mg/cc and cell diameters less than about 1 .mu.m is produced. Also disclosed are the foams produced by the process.

  15. Low density microcellular foams

    DOE Patents [OSTI]

    LeMay, J.D.

    1991-11-19T23:59:59.000Z

    Disclosed is a process of producing microcellular foam which comprises the steps of: (a) selecting a multifunctional epoxy oligomer resin; (b) mixing said epoxy resin with a non-reactive diluent to form a resin-diluent mixture; (c) forming a diluent containing cross-linked epoxy gel from said resin-diluent mixture; (d) replacing said diluent with a solvent therefore; (e) replacing said solvent with liquid carbon dioxide; and (f) vaporizing off said liquid carbon dioxide under supercritical conditions, whereby a foam having a density in the range of 35-150 mg/cc and cell diameters less than about 1 [mu]m is produced. Also disclosed are the foams produced by the process. 8 figures.

  16. Nuclear Energy Density Optimization

    E-Print Network [OSTI]

    M. Kortelainen; T. Lesinski; J. Moré; W. Nazarewicz; J. Sarich; N. Schunck; M. V. Stoitsov; S. Wild

    2010-05-27T23:59:59.000Z

    We carry out state-of-the-art optimization of a nuclear energy density of Skyrme type in the framework of the Hartree-Fock-Bogoliubov (HFB) theory. The particle-hole and particle-particle channels are optimized simultaneously, and the experimental data set includes both spherical and deformed nuclei. The new model-based, derivative-free optimization algorithm used in this work has been found to be significantly better than standard optimization methods in terms of reliability, speed, accuracy, and precision. The resulting parameter set UNEDFpre results in good agreement with experimental masses, radii, and deformations and seems to be free of finite-size instabilities. An estimate of the reliability of the obtained parameterization is given, based on standard statistical methods. We discuss new physics insights offered by the advanced covariance analysis.

  17. Low density microcellular foams

    DOE Patents [OSTI]

    Aubert, James H. (Albuquerque, NM); Clough, Roger L. (Albuquerque, NM); Curro, John G. (Placitas, NM); Quintana, Carlos A. (Albuquerque, NM); Russick, Edward M. (Albuquerque, NM); Shaw, Montgomery T. (Mansfield Center, CT)

    1987-01-01T23:59:59.000Z

    Low density, microporous polymer foams are provided by a process which comprises forming a solution of polymer and a suitable solvent followed by rapid cooling of the solution to form a phase-separated system and freeze the phase-separated system. The phase-separated system comprises a polymer phase and a solvent phase, each of which is substantially continuous within the other. The morphology of the polymer phase prior to and subsequent to freezing determine the morphology of the resultant foam. Both isotropic and anisotropic foams can be produced. If isotropic foams are produced, the polymer and solvent are tailored such that the solution spontaneously phase-separates prior to the point at which any component freezes. The morphology of the resultant polymer phase determines the morphology of the resultant foam and the morphology of the polymer phase is retained by cooling the system at a rate sufficient to freeze one or both components of the system before a change in morphology can occur. Anisotropic foams are produced by forming a solution of polymer and solvent that will not phase separate prior to freezing of one or both components of the solution. In such a process, the solvent typically freezes before phase separation occurs. The morphology of the resultant frozen two-phase system determines the morphology of the resultant foam. The process involves subjecting the solution to essentially one-dimensional cooling. Means for subjecting such a solvent to one-dimensional cooling are also provided. Foams having a density of less than 0.1 g/cc and a uniform cell size of less than 10 .mu.m and a volume such that the foams have a length greater than 1 cm are provided.

  18. Low density microcellular foams

    DOE Patents [OSTI]

    Aubert, J.H.; Clough, R.L.; Curro, J.G.; Quintana, C.A.; Russick, E.M.; Shaw, M.T.

    1985-10-02T23:59:59.000Z

    Low density, microporous polymer foams are provided by a process which comprises forming a solution of polymer and a suitable solvent followed by rapid cooling of the solution to form a phase-separated system and freeze the phase-separated system. The phase-separated system comprises a polymer phase and a solvent phase, each of which is substantially continuous within the other. The morphology of the polymer phase prior to and subsequent to freezing determine the morphology of the resultant foam. Both isotropic and anisotropic foams can be produced. If isotropic foams are produced, the polymer and solvent are tailored such that the solution spontaneously phase-separates prior to the point at which any component freezes. The morphology of the resultant polymer phase determines the morphology of the reusltant foam and the morphology of the polymer phase is retained by cooling the system at a rate sufficient to freeze one or both components of the system before a change in morphology can occur. Anisotropic foams are produced by forming a solution of polymer and solvent that will not phase separate prior to freezing of one or both components of the solution. In such a process, the solvent typically freezes before phase separation occurs. The morphology of the resultant frozen two-phase system determines the morphology of the resultant foam. The process involves subjecting the solution to essentially one-dimensional cooling. Foams having a density of less than 0.1 g/cc and a uniform cell size of less than 10 ..mu..m and a volume such that the foams have a length greater than 1 cm are provided.

  19. Vortex dynamics in 4 Banavara N. Shashikanth

    E-Print Network [OSTI]

    Shashikanth, Banavara N.

    Vortex dynamics in 4 Banavara N. Shashikanth Citation: J. Math. Phys. 53, 013103 (2012); doi: 10 OF MATHEMATICAL PHYSICS 53, 013103 (2012) Vortex dynamics in R4 Banavara N. Shashikantha) Mechanical and Aerospace dynamics of Euler's equations for a constant density fluid flow in R4 is studied. Most of the paper focuses

  20. Fuel-Borne Catalyst Assisted DPF regeneration on a Renault truck MD9 Engine

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn't YourTransport inEnergy0.pdfTechnologies ProgramOutfitted with SCR | Department of Energy

  1. DOE Zero Energy Ready Home Case Study 2013: Nexus EnergyHomes, Frederick, MD

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn't Your Destiny: Theof"WaveInteractionsMaterials | DepartmentEnergyNew Town BuildersNexus

  2. DOE Zero Energy Ready Home Case Study, Nexus EnergyHomes, Frederick, MD,

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn't Your Destiny: Theof"WaveInteractionsMaterials |Production | Department of Energy Study,

  3. VA-MD-DC Hydrogen Education for Decision Makers | Department of Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your DensityEnergy U.S.-China Electric Vehicle and03/02 TUE 08:59CapabilityVulnerabilities |2 1

  4. Evaluation of Powertrain Options and Component Sizing for MD and HD

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn't Your Destiny:RevisedAdvisoryStandardGeneration |10 DOEGoalsEvaluation11 DOEEmissions from

  5. Early maturation processes in coal. Part 2: Reactive dynamics simulations using the ReaxFF reactive force field on Morwell Brown coal structures

    E-Print Network [OSTI]

    Goddard III, William A.

    Early maturation processes in coal. Part 2: Reactive dynamics simulations using the ReaxFF reactive force field on Morwell Brown coal structures Elodie Salmon a , Adri C.T. van Duin b , François Lorant Brown coal using the ReaxFF reactive force field. We find that these reactive MD simulations

  6. Wood-Fiber/High-Density-Polyethylene Composites: Compounding Process

    E-Print Network [OSTI]

    Wood-Fiber/High-Density-Polyethylene Composites: Compounding Process J. Z. Lu,1 Q. Wu,1 I. I strength and flexural modulus of the resultant composites. With 50 wt % wood fiber, the optimum compounding of the modified blends and the dynamic mechanical properties of the resultant composites. The melt torque

  7. Model Predictive Control of Variable Density Multiphase Flows Governed by

    E-Print Network [OSTI]

    Hinze, Michael

    of model predictive control (MPC) consists in steering or keeping the state of a dynamical systemModel Predictive Control of Variable Density Multiphase Flows Governed by Diffuse Interface Models appearing in the model predictive control strategy. The resulting control concept is known as instantaneous

  8. Molecular Dynamic Approach of Enhanced Self-Propelled Nano-Droplet Motion on Wettability Gradient Surfaces

    E-Print Network [OSTI]

    Chakraborty, Monojit; Bhusan, Richa; DasGupta, Sunando

    2015-01-01T23:59:59.000Z

    Droplet motion over a surface with wettability gradient has been simulated using molecular dynamics (MD) simulation to highlight the underlying physics. GROMACS and Visual Molecular Dynamics (VMD) were used for simulation and intermittent visualization of the droplet configuration respectively. The simulations mimic experiments in a comprehensive manner wherein micro-sized droplets are propelled by surface wettability gradient against a number of retarding forces. The liquid-wall Lennard-Jones interaction parameter and the substrate temperature were varied to explore their effects on the three-phase contact line friction coefficient. The contact line friction was observed to be a strong function of temperature at atomistic scales, confirming the experimentally observed inverse functionality between the coefficient of contact line friction and increase in temperatures. These MD simulation results were successfully compared with the results from a model for self-propelled droplet motion on gradient surfaces.

  9. Energy trapping from Hagedorn densities of states

    E-Print Network [OSTI]

    Connor Behan; Klaus Larjo; Nima Lashkari; Brian Swingle; Mark Van Raamsdonk

    2013-04-26T23:59:59.000Z

    In this note, we construct simple stochastic toy models for holographic gauge theories in which distributions of energy on a collection of sites evolve by a master equation with some specified transition rates. We build in only energy conservation, locality, and the standard thermodynamic requirement that all states with a given energy are equally likely in equilibrium. In these models, we investigate the qualitative behavior of the dynamics of the energy distributions for different choices of the density of states for the individual sites. For typical field theory densities of states (\\log(\\rho(E)) ~ E^{\\alphaenergy spread out relatively quickly. For large N gauge theories with gravitational duals, the density of states for a finite volume of field theory degrees of freedom typically includes a Hagedorn regime (\\log(\\rho(E)) ~ E). We find that this gives rise to a trapping of energy in subsets of degrees of freedom for parametrically long time scales before the energy leaks away. We speculate that this Hagedorn trapping may be part of a holographic explanation for long-lived gravitational bound states (black holes) in gravitational theories.

  10. Directions to the River's Edge Catering & Conference Center, Naval Air Station Patuxent River For mapping GPS program reference, Lexington Park, MD is the town just outside the base gates. Physical

    E-Print Network [OSTI]

    Yener, Aylin

    Rev 0310 Directions to the River's Edge Catering & Conference Center, Naval Air Station Patuxent. Physical address is 46870 Tate Road ­ Bldg 2815, Patuxent River, MD. 20670. REC&C (301) 342-6210. From River For mapping GPS program reference, Lexington Park, MD is the town just outside the base gates

  11. Dynamical multi-breakup processes in the {sup 124}Sn+{sup 64}Ni system at 35 MeV/nucleon

    SciTech Connect (OSTI)

    Papa, M.; Cardella, G.; De Filippo, E.; Giuliani, G.; Lanzano, G.; Pagano, A.; Pirrone, S.; Politi, G.; Porto, F.; Verde, G. [INFN, Sezione di Catania and Dipartimento di Fisica, Universita di Catania (Italy); Amorini, F.; Anzalone, A.; Bonasera, A.; Cavallaro, S.; Colonna, M.; Di Toro, M.; Giustolisi, F.; Iacono-Manno, M.; La Guidara, E.; Lanzalone, G. [INFN, Laboratori Nazionali del Sud and Dipartimento di Fisica, Universita di Catania (Italy)] (and others)

    2007-05-15T23:59:59.000Z

    Multi-breakup processes for the {sup 124}Sn+{sup 64}Ni system at 35 MeV/nucleon have been studied with the forward part of the CHIMERA detector. An extensive comparison between experimental data corresponding to almost complete ternary events and constrained molecular dynamics (CoMD-II) calculations suggests different characteristic times in the selected processes. This is in agreement with previous studies of the same reaction already published concerning the prompt intermediate-mass-fragment emission. Stimulated by CoMD-II calculations, we investigate the existence of more complex dynamical multi-breakup processes occurring on the same time scale. A detailed study of the rotational dynamics leading to slower dynamical fission processes is also presented.

  12. Generation of Gaussian Density Fields

    E-Print Network [OSTI]

    Hugo Martel

    2005-07-15T23:59:59.000Z

    This document describes analytical and numerical techniques for the generation of Gaussian density fields, which represent cosmological density perturbations. The mathematical techniques involved in the generation of density harmonics in k-space, the filtering of the density fields, and the normalization of the power spectrum to the measured temperature fluctuations of the Cosmic Microwave Background, are presented in details. These techniques are well-known amongst experts, but the current literature lacks a formal description. I hope that this technical report will prove useful to new researchers moving into this field, sparing them the task of reinventing the wheel.

  13. Minimization of Fractional Power Densities

    E-Print Network [OSTI]

    Minimization of Fractional Power Densities. Robert Hardt, Rice University. Abstract: A k dimensional rectifiable current is given by an oriented k dimensional

  14. Canonical density matrix perturbation theory

    E-Print Network [OSTI]

    Niklasson, Anders M N; Rubensson, Emanuel H; Rudberg, Elias

    2015-01-01T23:59:59.000Z

    Density matrix perturbation theory [Niklasson and Challacombe, Phys. Rev. Lett. 92, 193001 (2004)] is generalized to canonical (NVT) free energy ensembles in tight-binding, Hartree-Fock or Kohn-Sham density functional theory. The canonical density matrix perturbation theory can be used to calculate temperature dependent response properties from the coupled perturbed self-consistent field equations as in density functional perturbation theory. The method is well suited to take advantage of sparse matrix algebra to achieve linear scaling complexity in the computational cost as a function of system size for sufficiently large non-metallic materials and metals at high temperatures.

  15. Advances in modeling gradual solar energetic particle events q Applied Physics Laboratory, Johns Hopkins University, 11100 Johns Hopkins Road, Laurel, MD 20723, USA

    E-Print Network [OSTI]

    Sanahuja, Blai

    Advances in modeling gradual solar energetic particle events q D. Lario * Applied Physics Laboratory, Johns Hopkins University, 11100 Johns Hopkins Road, Laurel, MD 20723, USA Received 19 October 2002; accepted 8 July 2005 Abstract Solar energetic particles pose one of the most serious hazards

  16. Dynamics of a Submesoscale Surface Ocean Density Front

    E-Print Network [OSTI]

    Abramczyk, Marshall

    2012-01-01T23:59:59.000Z

    dominant portion of the ocean energy [Capet et al. , 2008a].are important for the ocean energy budget and biogeochemicalrelevance for the ocean energy budget and nutrient

  17. Dynamics of a Submesoscale Surface Ocean Density Front

    E-Print Network [OSTI]

    Abramczyk, Marshall

    2012-01-01T23:59:59.000Z

    Shchepetkin, A. 2008a. Mesoscale to submesoscale transitionShchepetkin, A. 2008b. Mesoscale to submesoscale transitionShchepetkin, A. 2008c. Mesoscale to submesoscale transition

  18. Chiral dynamics and peripheral transverse densities | SciTech Connect

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office511041clothAdvanced Materials Advanced. C o w l i t z CPlasma of theChemistryChicagoFuel CellX I Aand

  19. Towards Microsecond Biological Molecular Dynamics Simulations on Hybrid Processors

    SciTech Connect (OSTI)

    Hampton, Scott S [ORNL; Agarwal, Pratul K [ORNL

    2010-01-01T23:59:59.000Z

    Biomolecular simulations continue to become an increasingly important component of molecular biochemistry and biophysics investigations. Performance improvements in the simulations based on molecular dynamics (MD) codes are widely desired. This is particularly driven by the rapid growth of biological data due to improvements in experimental techniques. Unfortunately, the factors, which allowed past performance improvements of MD simulations, particularly the increase in microprocessor clock frequencies, are no longer improving. Hence, novel software and hardware solutions are being explored for accelerating the performance of popular MD codes. In this paper, we describe our efforts to port and optimize LAMMPS, a popular MD framework, on hybrid processors: graphical processing units (GPUs) accelerated multi-core processors. Our implementation is based on porting the computationally expensive, non-bonded interaction terms on the GPUs, and overlapping the computation on the CPU and GPUs. This functionality is built on top of message passing interface (MPI) that allows multi-level parallelism to be extracted even at the workstation level with the multi-core CPUs as well as extend the implementation on GPU clusters. The results from a number of typically sized biomolecular systems are provided and analysis is performed on 3 generations of GPUs from NVIDIA. Our implementation allows up to 30-40 ns/day throughput on a single workstation as well as significant speedup over Cray XT5, a high-end supercomputing platform. Moreover, detailed analysis of the implementation indicates that further code optimization and improvements in GPUs will allow {approx}100 ns/day throughput on workstations and inexpensive GPU clusters, putting the widely-desired microsecond simulation time-scale within reach to a large user community.

  20. Trajectory mixture density networks with multiple mixtures for acoustic-articulatory inversion 

    E-Print Network [OSTI]

    Richmond, Korin

    We have previously proposed a trajectory model which is based on a mixture density network (MDN) trained with target variables augmented with dynamic features together with an algorithm for estimating maximum likelihood trajectories which respects...

  1. Detecting Density Variations and Nanovoids

    SciTech Connect (OSTI)

    Miller, Michael K [ORNL; Longstreth-Spoor, L. [Washington University, St. Louis; Kelton, K. F. [Washington University, St. Louis

    2011-01-01T23:59:59.000Z

    A combination of simulated and experimental data has been used to investigate the size range of nanovoids that can be detected in atom probe tomography data. Simulated atom probe tomography data have revealed that nanovoids as small as 1 nm in diameter can be detected in atom probe tomography data with the use of iso-density surfaces. Iso-density surfaces may be used to quantify the size, morphology and number density of nanovoids and other variations in density in atom probe tomography data. Experimental data from an aluminum-yttrium-iron metallic glass ribbon have revealed the effectiveness of this approach. Combining iso-density surfaces with atom maps also permits the segregation of solute to the nanovoids to be investigated. Field ion microscopy and thin section atom maps have also been used to detect pores and larger voids.

  2. Direct Experimental Determination of Spectral Densities of Molecular Complexes

    E-Print Network [OSTI]

    Leonardo A. Pachon; Paul Brumer

    2014-10-15T23:59:59.000Z

    Determining the spectral density of a molecular system immersed in a proteomic scaffold and in contact to a solvent is a fundamental challenge in the coarse-grained description of, e.g., electron and energy transfer dynamics. Once the spectral density is characterized, all the time scales are captured and no artificial separation between fast and slow processes need be invoked. Based on the fluorescence Stokes shift function, we utilize a simple and robust strategy to extract the spectral density of a number of molecular complexes from available experimental data. Specifically, we show that experimental data for dye molecules in several solvents, amino acid proteins in water, and some photochemical systems (e.g., rhodopsin and green fluorescence proteins), are well described by a three-parameter family of sub-Ohmic spectral densities that are characterized by a fast initial Gaussian-like decay followed by a slow algebraic-like decay rate at long times.

  3. Direct experimental determination of spectral densities of molecular complexes

    SciTech Connect (OSTI)

    Pachón, Leonardo A. [Grupo de Física Atómica y Molecular, Instituto de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín (Colombia); Chemical Physics Theory Group, Department of Chemistry and Center for Quantum Information and Quantum Control, University of Toronto, Toronto, Ontario M5S 3H6 (Canada); Brumer, Paul [Chemical Physics Theory Group, Department of Chemistry and Center for Quantum Information and Quantum Control, University of Toronto, Toronto, Ontario M5S 3H6 (Canada)

    2014-11-07T23:59:59.000Z

    Determining the spectral density of a molecular system immersed in a proteomic scaffold and in contact to a solvent is a fundamental challenge in the coarse-grained description of, e.g., electron and energy transfer dynamics. Once the spectral density is characterized, all the time scales are captured and no artificial separation between fast and slow processes need to be invoked. Based on the fluorescence Stokes shift function, we utilize a simple and robust strategy to extract the spectral density of a number of molecular complexes from available experimental data. Specifically, we show that experimental data for dye molecules in several solvents, amino acid proteins in water, and some photochemical systems (e.g., rhodopsin and green fluorescence proteins), are well described by a three-parameter family of sub-Ohmic spectral densities that are characterized by a fast initial Gaussian-like decay followed by a slow algebraic-like decay rate at long times.

  4. Nuclear Energy Density Functionals: What do we really know?

    E-Print Network [OSTI]

    Bulgac, Aurel; Jin, Shi

    2015-01-01T23:59:59.000Z

    We present the simplest nuclear energy density functional (NEDF) to date, determined by only 4 significant phenomenological parameters, yet capable of fitting measured nuclear masses with better accuracy than the Bethe-Weizs\\"acker mass formula, while also describing density structures (charge radii, neutron skins etc.) and time-dependent phenomena (induced fission, giant resonances, low energy nuclear collisions, etc.). The 4 significant parameters are necessary to describe bulk nuclear properties (binding energies and charge radii); an additional 2 to 3 parameters have little influence on the bulk nuclear properties, but allow independent control of the density dependence of the symmetry energy and isovector excitations, in particular the Thomas-Reiche-Kuhn sum rule. This Hohenberg-Kohn-style of density functional theory successfully realizes Weizs\\"acker's ideas and provides a computationally tractable model for a variety of static nuclear properties and dynamics, from finite nuclei to neutron stars, where...

  5. Observation of the Density Minimum in Deeply Supercooled Confined Water

    E-Print Network [OSTI]

    Dazhi Liu; Yang Zhang; Chia-Cheng Chen; Chung-Yuan Mou; Peter H Poole; Sow-Hsin Chen

    2007-04-17T23:59:59.000Z

    Small angle neutron scattering (SANS) is used to measure the density of heavy water contained in 1-D cylindrical pores of mesoporous silica material MCM-41-S-15, with pores of diameter of 15+-1 A. In these pores the homogenous nucleation process of bulk water at 235 K does not occur and the liquid can be supercooled down to at least 160 K. The analysis of SANS data allows us to determine the absolute value of the density of D2O as a function of temperature. We observe a density minimum at 210+-5 K with a value of 1.041+-0.003 g/cm3. We show that the results are consistent with the predictions of molecular dynamics simulations of supercooled bulk water. This is the first experimental report of the existence of the density minimum in supercooled water.

  6. Direct Experimental Determination of Spectral Densities of Molecular Complexes

    E-Print Network [OSTI]

    Pachon, Leonardo A

    2014-01-01T23:59:59.000Z

    Determining the spectral density of a molecular system immersed in a proteomic scaffold and in contact to a solvent is a fundamental challenge in the coarse-grained description of, e.g., electron and energy transfer dynamics. Once the spectral density is characterized, all the time scales are captured and no artificial separation between fast and slow processes need be invoked. Based on the fluorescence Stokes shift function, we utilize a simple and robust strategy to extract the spectral density of a number of molecular complexes from available experimental data. Specifically, we show that experimental data for dye molecules in several solvents, amino acid proteins in water, and some photochemical systems (e.g., rhodopsin and green fluorescence proteins), are well described by a three-parameter family of sub-Ohmic spectral densities that are characterized by a fast initial Gaussian-like decay followed by a slow algebraic-like decay rate at long times.

  7. Function and dynamics of aptamers: A case study on the malachite green aptamer

    SciTech Connect (OSTI)

    Wang, Tianjiao

    2008-12-01T23:59:59.000Z

    Aptamers are short single-stranded nucleic acids that can bind to their targets with high specificity and high affinity. To study aptamer function and dynamics, the malachite green aptamer was chosen as a model. Malachite green (MG) bleaching, in which an OH- attacks the central carbon (C1) of MG, was inhibited in the presence of the malachite green aptamer (MGA). The inhibition of MG bleaching by MGA could be reversed by an antisense oligonucleotide (AS) complementary to the MGA binding pocket. Computational cavity analysis of the NMR structure of the MGA-MG complex predicted that the OH{sup -} is sterically excluded from the C1 of MG. The prediction was confirmed experimentally using variants of the MGA with changes in the MG binding pocket. This work shows that molecular reactivity can be reversibly regulated by an aptamer-AS pair based on steric hindrance. In addition to demonstrate that aptamers could control molecular reactivity, aptamer dynamics was studied with a strategy combining molecular dynamics (MD) simulation and experimental verification. MD simulation predicted that the MG binding pocket of the MGA is largely pre-organized and that binding of MG involves reorganization of the pocket and a simultaneous twisting of the MGA terminal stems around the pocket. MD simulation also provided a 3D-structure model of unoccupied MGA that has not yet been obtained by biophysical measurements. These predictions were consistent with biochemical and biophysical measurements of the MGA-MG interaction including RNase I footprinting, melting curves, thermodynamic and kinetic constants measurement. This work shows that MD simulation can be used to extend our understanding of the dynamics of aptamer-target interaction which is not evident from static 3D-structures. To conclude, I have developed a novel concept to control molecular reactivity by an aptamer based on steric protection and a strategy to study the dynamics of aptamer-target interaction by combining MD simulation and experimental verification. The former has potential application in controlling metabolic reactions and protein modifications by small reactants and the latter may serve as a general approach to study the dynamics of aptamer-target interaction for new insights into mechanisms of aptamer-target recognition.

  8. Coarse Grained Quantum Dynamics

    E-Print Network [OSTI]

    Cesar Agon; Vijay Balasubramanian; Skyler Kasko; Albion Lawrence

    2014-12-09T23:59:59.000Z

    We consider coarse graining a quantum system divided between short distance and long distance degrees of freedom, which are coupled by the Hamiltonian. Observations using purely long distance observables can be described by the reduced density matrix that arises from tracing out the short-distance observables. The dynamics of this density matrix is that of an open quantum system, and is nonlocal in time, on the order of some short time scale. We describe these dynamics in a model system with a simple hierarchy of energy gaps $\\Delta E_{UV} > \\Delta E_{IR}$, in which the coupling between high-and low-energy degrees of freedom is treated to second order in perturbation theory. We then describe the equations of motion under suitable time averaging, reflecting the limited time resolution of actual experiments, and find an expansion of the master equation in powers of $\\Delta E_{IR}/\\Delta E_{UV}$, in which the failure of the system to be Hamiltonian or even Markovian appears at higher orders in this ratio. We compute the evolution of the density matrix in two specific examples -- coupled spins, and linearly coupled simple harmonic oscillators. Finally, we discuss the evolution of the density matrix using the path integral approach, computing the Feynman-Vernon influence functional for the IR degrees of freedom in perturbation theory, and argue that this influence functional is the correct analog of the Wilsonian effective action for this problem.

  9. Dynamic and Functional Musculoskeletal Imaging; Editors in Chief, David Karasick, M.D., Mark E. Schweitzer, M.D.; Guest Editor, Garry E. Gold, M.D. Seminars in Musculoskeletal Radiology, Volume 7, Number 4, 2003. Address for correspondence and reprint req

    E-Print Network [OSTI]

    Delp, Scott

    , Stanford, CA, 3Diagnostic Radiology Center, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA(212) 584-4662. 1089-7860,p;2003,07,04,287,296,ftx,en;smr00305x. Cine Phase-Contrast Magnetic Resonance

  10. Low density metal hydride foams

    DOE Patents [OSTI]

    Maienschein, Jon L. (Oakland, CA); Barry, Patrick E. (Pleasant Hill, CA)

    1991-01-01T23:59:59.000Z

    Disclosed is a low density foam having a porosity of from 0 to 98% and a density less than about 0.67 gm/cc, prepared by heating a mixture of powered lithium hydride and beryllium hydride in an inert atmosphere at a temperature ranging from about 455 to about 490 K for a period of time sufficient to cause foaming of said mixture, and cooling the foam thus produced. Also disclosed is the process of making the foam.

  11. Enhanced residual entropy in high-density nanoconfined bilayer ice

    E-Print Network [OSTI]

    Fabiano Corsetti; Jon Zubeltzu; Emilio Artacho

    2015-06-15T23:59:59.000Z

    A novel kind of crystal order in high-density nanoconfined bilayer ice is proposed from molecular dynamics and density-functional theory simulations. A first-order transition is observed between a low-temperature proton-ordered solid and a high-temperature proton-disordered solid. The latter is shown to possess crystalline order for the oxygen positions, arranged on a close-packed triangular lattice with AA stacking. Uniquely amongst the ice phases, the triangular bilayer is characterized by two levels of disorder (for the bonding network and for the protons) which results in a residual entropy twice that of bulk ice.

  12. Temperature Power Law of Equilibrium Heavy Particle Density

    E-Print Network [OSTI]

    Sh. Matsumoto; M. Yoshimura

    1999-10-19T23:59:59.000Z

    A standard calculation of the energy density of heavy stable particles that may pair-annihilate into light particles making up thermal medium is performed to second order of coupling, using the technique of thermal field theory. At very low temperatures a power law of temperature is derived for the energy density of the heavy particle. This is in sharp contrast to the exponentially suppressed contribution estimated from the ideal gas distribution function. The result supports a previous dynamical calculation based on the Hartree approximation, and implies that the relic abundance of dark matter particles is enhanced compared to that based on the Boltzmann equation.

  13. Maximum-likelihood density modification

    SciTech Connect (OSTI)

    Terwilliger, Thomas C., E-mail: terwilliger@lanl.gov [Structural Biology Group, Mail Stop M888, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2000-08-01T23:59:59.000Z

    A likelihood-based density modification approach is developed that can incorporate expected electron-density information from a wide variety of sources. A likelihood-based approach to density modification is developed that can be applied to a wide variety of cases where some information about the electron density at various points in the unit cell is available. The key to the approach consists of developing likelihood functions that represent the probability that a particular value of electron density is consistent with prior expectations for the electron density at that point in the unit cell. These likelihood functions are then combined with likelihood functions based on experimental observations and with others containing any prior knowledge about structure factors to form a combined likelihood function for each structure factor. A simple and general approach to maximizing the combined likelihood function is developed. It is found that this likelihood-based approach yields greater phase improvement in model and real test cases than either conventional solvent flattening and histogram matching or a recent reciprocal-space solvent-flattening procedure [Terwilliger (1999 ?), Acta Cryst. D55, 1863–1871].

  14. Phonons and related crystal properties from density-functional perturbation theory

    E-Print Network [OSTI]

    Wu, Zhigang

    -Functional Perturbation Theory 516 A. Lattice dynamics from electronic-structure theory 516 B. Density-functional theory July 2001) This article reviews the current status of lattice-dynamical calculations in crystals, using specialized topics are treated, including the implementation for metals, the calculation of the response

  15. Symmetries in open quantum dynamics

    E-Print Network [OSTI]

    Thomas F. Jordan

    2014-08-20T23:59:59.000Z

    Simple examples are used to introduce and examine a Heisenberg picture of symmetries of open quantum dynamics that can be described by unitary operators. When the symmetries are for Hamiltonian dynamics of an entire system, and the spectrum of the Hamiltonian operator has a lower bound, the symmetry operators commute with the Hamiltonian operator. An example shows that symmetry operators need not commute with the Hamiltonian operator when the spectrum of the Hamiltonian does not have a lower bound. There are many more symmetries that are only for the open dynamics of a subsystem and are described by unitary operators that do not commute with the Hamiltonian for the dynamics of the entire system. Examples show how these symmetries alone can reveal properties of the dynamics and reduce what needs to be done to work out the dynamics. A symmetry of the open dynamics of a subsystem can imply properties of the dynamics for the entire system that are not implied by the symmetries of the dynamics of the entire system. The symmetries are generally not related to constants of the motion for the open dynamics of the subsystem. There are symmetries of the open dynamics of a subsystem that depend only on the dynamics. In the simplest examples, these are also symmetries of the dynamics of the entire system. There are many more symmetries, of a new kind, that also depend on correlations, or absence of correlations, between the subsystem and the rest of the entire system, or on the state of the rest of the entire system. Symmetries that depend on correlations generally cannot be seen in the Schr\\"{o}dinger picture as symmetries of dynamical maps of density matrices for the subsystem.

  16. Longitudinal density monitor for the LHC

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

    Jeff, A.; Andersen, M.; Boccardi, A.; Bozyigit, S.; Bravin, E.; Lefevre, T.; Rabiller, A.; Roncarolo, F.; Welsch, C. P.; Fisher, A. S.

    2012-03-01T23:59:59.000Z

    The longitudinal density monitor (LDM) is primarily intended for the measurement of the particle population in nominally empty rf buckets. These so-called satellite or ghost bunches can cause problems for machine protection as well as influencing the luminosity calibration of the LHC. The high dynamic range of the system allows measurement of ghost bunches with as little as 0.01% of the main bunch population at the same time as characterization of the main bunches. The LDM is a single-photon counting system using visible synchrotron light. The photon detector is a silicon avalanche photodiode operated in Geiger mode, which allows the longitudinal distribution of the LHC beams to be measured with a resolution of 90 ps. Results from the LDM are presented, including a proposed method for constructing a 3-dimensional beam density map by scanning the LDM sensor in the transverse plane. In addition, we present a scheme to improve the sensitivity of the system by using an optical switching technique.

  17. The ESO Nearby Abell Cluster Survey IX. The morphology-radius and morphology-density relations in rich galaxy clusters

    E-Print Network [OSTI]

    T. Thomas; P. Katgert

    2005-10-10T23:59:59.000Z

    We study the morphology-radius (MR-) and morphology-density (MD-) relations for a sample of about 850 galaxies (with M = -22), the S0 galaxies and the early spirals have different Sigma1-distributions. The reason for this is that Sigma1 is much less correlated with R than is Sigma10, and thus has much less cross-talk from the (MR-) relation. On average, the 'normal' ellipticals populate environments with higher projected density than do the S0 galaxies while the early spirals populate even less dense environments. The segregation of the brightest ellipticals and the late spirals is driven mostly by global factors, while the segregation between 'normal' ellipticals, S0 galaxies and early spirals is driven primarily by local factors.

  18. Hybrid Architectural Dynamic Thermal Management Kevin Skadron

    E-Print Network [OSTI]

    Skadron, Kevin

    . The challenge is that even though this reduction in power density reduces heat dissipation and can be used­3 or more per watt of heat dissipated [1, 6], making it more difficult to deploy new systems. Cooling costs management (DTM) dynamically reduces the power density on the chip to maintain safe operating tem- peratures

  19. Saturated Sodium Chloride Solution under an External Static Electric Field: a Molecular Dynamics Study

    E-Print Network [OSTI]

    Gan Ren; Yanting Wang

    2015-05-02T23:59:59.000Z

    The behavior of saturated aqueous sodium chloride solutions under a constant external electric field (E) was studied by molecular dynamics (MD) simulation. Our dynamic MD simulations have indicated that the irreversible nucleation process towards crystallization is accelerated by a moderate E, but retarded or even prohibited under a stronger E, which can be understood by the competition between self-diffusion and drift motion. The former increases with E resulting in the acceleration of the nucleation process, and the latter tears oppositely charged ions more apart under a stronger E leading to the deceleration of nucleation. Moreover, our steady-state MD simulations have indicated that a first-order phase transition happens in saturated solutions only when the applied E is below a certain threshold Ec, and the ratio of crystallized ions does not change with the electric field. The magnitude of Ec increases with concentration, because larger clusters are easy to form in a more concentrated solution and require a stronger E to dissociate them.

  20. Frontiers for Discovery in High Energy Density Physics

    SciTech Connect (OSTI)

    Davidson, R. C.; Katsouleas, T.; Arons, J.; Baring, M.; Deeney, C.; Di Mauro, L.; Ditmire, T.; Falcone, R.; Hammer, D.; Hill, W.; Jacak, B.; Joshi, C.; Lamb, F.; Lee, R.; Logan, B. G.; Melissinos, A.; Meyerhofer, D.; Mori, W.; Murnane, M.; Remington, B.; Rosner, R.; Schneider, D.; Silvera, I.; Stone, J.; Wilde, B.; Zajc. W.

    2004-07-20T23:59:59.000Z

    The report is intended to identify the compelling research opportunities of high intellectual value in high energy density physics. The opportunities for discovery include the broad scope of this highly interdisciplinary field that spans a wide range of physics areas including plasma physics, laser and particle beam physics, nuclear physics, astrophysics, atomic and molecular physics, materials science and condensed matter physics, intense radiation-matter interaction physics, fluid dynamics, and magnetohydrodynamics

  1. Dynamics of capillary condensation in aerogels

    SciTech Connect (OSTI)

    Nomura, R.; Miyashita, W.; Yoneyama, K.; Okuda, Y. [Department of Condensed Matter Physics, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro, Tokyo 152-8551 (Japan)

    2006-03-15T23:59:59.000Z

    Dynamics of capillary condensation of liquid {sup 4}He in various density silica aerogels was investigated systematically. Interfaces were clearly visible when bulk liquid was rapidly sucked into the aerogel. Time evolution of the interface positions was consistent with the Washburn model and their effective pore radii were obtained. Condensation was a single step in a dense aerogel and two steps in a low density aerogel. Crossover between the two types of condensation was observed in an intermediate density aerogel. Variety of the dynamics may be the manifestation of the fractal nature of aerogels which had a wide range of distribution of pore radii.

  2. A molecular dynamics investigation of the unusual concentration dependencies of Fick diffusivities in silica mesopores

    SciTech Connect (OSTI)

    Krishna, Rajamani; van Baten, Jasper M

    2011-01-01T23:59:59.000Z

    Molecular Dynamics (MD) simulations were carried out to determine the self-diffusivitiy, D{sub i,self}, the Maxwell–Stefan diffusivity, Ð{sub i}, and the Fick diffusivity, D{sub i}, for methane (C1), ethane (C2), propane (C3), n-butane (nC4), n-pentane (nC5), n-hexane (nC6), n-heptane (nC7), and cyclohexane (cC6) in cylindrical silica mesopores for a range of pore concentrations. The MD simulations show that zero-loading diffusivity Ð{sub i}(0) is consistently lower, by up to a factor of 20, than the values anticipated by the classical Knudsen formula. The concentration dependence of the Fick diffusivity, D{sub i} is found to be unusually complex, and displays a strong minimum in some cases; this characteristic can be traced to molecular clustering.

  3. Intercrystalline density on nanocrystalline nickel

    SciTech Connect (OSTI)

    Haasz, T.R.; Aust, K.T. [Univ. of Toronto, Ontario (Canada). Dept. of Metallurgy and Materials Science] [Univ. of Toronto, Ontario (Canada). Dept. of Metallurgy and Materials Science; Palumbo, G. [Ontario Hydro Research Div., Toronto, Ontario (Canada)] [Ontario Hydro Research Div., Toronto, Ontario (Canada); El-Sherik, A.M.; Erb, U. [Queen`s Univ., Kingston, Ontario (Canada). Dept. of Materials and Metallurgical Engineering] [Queen`s Univ., Kingston, Ontario (Canada). Dept. of Materials and Metallurgical Engineering

    1995-02-01T23:59:59.000Z

    Most methods currently available for the synthesis of nanostructured materials result in considerable residual porosity. Studies concerned with the novel structures and properties of these materials are thus compromised by the intrinsically high levels of porosity. As recently shown by Kristic et al., porosity can have a significant effect on fundamental materials properties such as Young`s modulus. One of the most promising techniques for the production of fully dense nanocrystalline materials is electrodeposition. In the present work, the residual porosity and density of nanostructured nickel produced by the electrodeposition method is assessed and discussed in light of the intrinsic intercrystalline density of nickel.

  4. Transverse charge and magnetization densities in the nucleon's chiral periphery

    SciTech Connect (OSTI)

    Granados, Carlos G. [JLAB Newport News, VA (United States); Weiss, Christian [JLAB Newport News, VA (United States)

    2014-01-01T23:59:59.000Z

    In the light-front description of nucleon structure the electromagnetic form factors are expressed in terms of frame-independent transverse densities of charge and magnetization. Recent work has studied the transverse densities at peripheral distances b = O(M{pi}{sup -1}), where they are governed by universal chiral dynamics and can be computed in a model-independent manner. Of particular interest is the comparison of the peripheral charge and magnetization densities. We summarize (a) their interpretation as spin-independent and -dependent current matrix elements; (b) the leading-order chiral effective field theory results; (c) their mechanical interpretation in the light-front formulation; (d) the large-N_c limit of QCD and the role of {Delta} intermediate states; (e) the connection with generalized parton distributions and peripheral high-energy scattering processes.

  5. Local thermodynamic equilibrium in rapidly heated high energy density plasmas

    SciTech Connect (OSTI)

    Aslanyan, V.; Tallents, G. J. [York Plasma Institute, Department of Physics, University of York, Heslington, York YO10 5DD (United Kingdom)

    2014-06-15T23:59:59.000Z

    Emission spectra and the dynamics of high energy density plasmas created by optical and Free Electron Lasers (FELs) depend on the populations of atomic levels. Calculations of plasma emission and ionization may be simplified by assuming Local Thermodynamic Equilibrium (LTE), where populations are given by the Saha-Boltzmann equation. LTE can be achieved at high densities when collisional processes are much more significant than radiative processes, but may not be valid if plasma conditions change rapidly. A collisional-radiative model has been used to calculate the times taken by carbon and iron plasmas to reach LTE at varying densities and heating rates. The effect of different energy deposition methods, as well as Ionization Potential Depression are explored. This work shows regimes in rapidly changing plasmas, such as those created by optical lasers and FELs, where the use of LTE is justified, because timescales for plasma changes are significantly longer than the times needed to achieve an LTE ionization balance.

  6. Density waves in the shearing sheet III. Disc heating

    E-Print Network [OSTI]

    B. Fuchs

    2001-04-25T23:59:59.000Z

    The problem of dynamical heating of galactic discs by spiral density waves is discussed using the shearing sheet model. The secular evolution of the disc is described quantitatively by a diffusion equation for the distribution function of stars in the space spanned by integrals of motion of the stars, in particular the radial action integral and an integral related to the angular momentum. Specifically, disc heating by a succession of transient, `swing amplified' density waves is studied. It is shown that such density waves lead predominantly to diffusion of stars in radial action space. The stochastical changes of angular momenta of the stars and the corresponding stochastic changes of the guiding centre radii of the stellar orbits induced by this process are much smaller.

  7. Statistical density modification using local pattern matching

    SciTech Connect (OSTI)

    Terwilliger, Thomas C.

    2007-01-23T23:59:59.000Z

    A computer implemented method modifies an experimental electron density map. A set of selected known experimental and model electron density maps is provided and standard templates of electron density are created from the selected experimental and model electron density maps by clustering and averaging values of electron density in a spherical region about each point in a grid that defines each selected known experimental and model electron density maps. Histograms are also created from the selected experimental and model electron density maps that relate the value of electron density at the center of each of the spherical regions to a correlation coefficient of a density surrounding each corresponding grid point in each one of the standard templates. The standard templates and the histograms are applied to grid points on the experimental electron density map to form new estimates of electron density at each grid point in the experimental electron density map.

  8. Training Session: Frederick, MD

    Broader source: Energy.gov [DOE]

    This 3.5-hour training provides builders with a comprehensive review of zero net-energy-ready home construction including the business case, detailed specifications, and opportunities to be...

  9. citation: Natio Hyattsville, MD

    E-Print Network [OSTI]

    Illinois at Chicago, University of

    Reform 75 Monitoring Health Care Reform: SelfReports of Health Insurance Premium Assistance & Program SESSION 1 SUMMARY 71 KAREN CYBULSKI, ANNE CIEMNECKI, AND KAREN BOGEN SESSION 2: Monitoring Health Care Survey 101 MARC W. ZODET, STEVEN C. HILL, AND SAMUEL H. ZUVEKAS The RWJF Health Care Public

  10. Complex Dynamics

    E-Print Network [OSTI]

    Complex Dynamics Bernardo Da Costa, Koushik Ramachandran, Jingjing Qu, and I had a two semester learning seminar in complex analysis and potential ...

  11. A current density distribution tool

    E-Print Network [OSTI]

    Jagush, Frederic A.

    1989-01-01T23:59:59.000Z

    . I. INTRODUCTION Current density distribution is an important consideration for those involved in electrochemical systems and electroplating in particular. In the printed wiring board (PWB) business, great emphasis is placed on the study of current... exist. Numerical techniques on the other hand, are usually easy to implement and are easily applicable to microcomputers. Their disadvantage as with any approximation technique is that the exactness of the results with This document follows the style...

  12. Updated Axion CDM energy density

    E-Print Network [OSTI]

    Ji-Haeng Huh

    2008-10-08T23:59:59.000Z

    We update cosmological bound on axion model. The contribution from the anharmonic effect and the newly introduced initial overshoot correction are considered. We present an explicit formula for the axion relic density in terms of the QCD scale Lambda_{QCD}, the current quark masses m_q's and the Peccei-Quinn scale F_a, including firstly introduced 1.85 factor which is from the initial overshoot.

  13. Relativistic Nuclear Energy Density Functionals: adjusting parameters to binding energies

    E-Print Network [OSTI]

    T. Niksic; D. Vretenar; P. Ring

    2008-09-08T23:59:59.000Z

    We study a particular class of relativistic nuclear energy density functionals in which only nucleon degrees of freedom are explicitly used in the construction of effective interaction terms. Short-distance (high-momentum) correlations, as well as intermediate and long-range dynamics, are encoded in the medium (nucleon density) dependence of the strength functionals of an effective interaction Lagrangian. Guided by the density dependence of microscopic nucleon self-energies in nuclear matter, a phenomenological ansatz for the density-dependent coupling functionals is accurately determined in self-consistent mean-field calculations of binding energies of a large set of axially deformed nuclei. The relationship between the nuclear matter volume, surface and symmetry energies, and the corresponding predictions for nuclear masses is analyzed in detail. The resulting best-fit parametrization of the nuclear energy density functional is further tested in calculations of properties of spherical and deformed medium-heavy and heavy nuclei, including binding energies, charge radii, deformation parameters, neutron skin thickness, and excitation energies of giant multipole resonances.

  14. Pion transverse charge density and the edge of hadrons

    SciTech Connect (OSTI)

    Carmignotto, Marco [Catholic University of America; Horn, Tanja [Catholic University of America; Miller, Gerald A. [University of Washington

    2014-08-01T23:59:59.000Z

    We use the world data on the pion form factor for space-like kinematics and a technique used to extract the proton transverse densities, to extract the transverse pion charge density and its uncertainty due to experimental uncertainties and incomplete knowledge of the pion form factor at large values of Q2. The pion charge density at small values of b<0.1 fm is dominated by this incompleteness error while the range between 0.1-0.3 fm is relatively well constrained. A comparison of pion and proton charge densities shows that the pion is denser than the proton for values of b<0.2 fm. The pion and proton distributions seem to be the same for values of b=0.2-0.6 fm. Future data from Jlab 12 GeV and the EIC will increase the dynamic extent of the data to higher values of Q2 and thus reduce the uncertainties in the extracted pion charge density.

  15. Accelerated molecular dynamics methods: introduction and recent developments

    SciTech Connect (OSTI)

    Uberuaga, Blas Pedro [Los Alamos National Laboratory; Voter, Arthur F [Los Alamos National Laboratory; Perez, Danny [Los Alamos National Laboratory; Shim, Y [UNIV OF TOLEDO; Amar, J G [UNIV OF TOLEDO

    2009-01-01T23:59:59.000Z

    A long-standing limitation in the use of molecular dynamics (MD) simulation is that it can only be applied directly to processes that take place on very short timescales: nanoseconds if empirical potentials are employed, or picoseconds if we rely on electronic structure methods. Many processes of interest in chemistry, biochemistry, and materials science require study over microseconds and beyond, due either to the natural timescale for the evolution or to the duration of the experiment of interest. Ignoring the case of liquids xxx, the dynamics on these time scales is typically characterized by infrequent-event transitions, from state to state, usually involving an energy barrier. There is a long and venerable tradition in chemistry of using transition state theory (TST) [10, 19, 23] to directly compute rate constants for these kinds of activated processes. If needed dynamical corrections to the TST rate, and even quantum corrections, can be computed to achieve an accuracy suitable for the problem at hand. These rate constants then allow them to understand the system behavior on longer time scales than we can directly reach with MD. For complex systems with many reaction paths, the TST rates can be fed into a stochastic simulation procedure such as kinetic Monte Carlo xxx, and a direct simulation of the advance of the system through its possible states can be obtained in a probabilistically exact way. A problem that has become more evident in recent years, however, is that for many systems of interest there is a complexity that makes it difficult, if not impossible, to determine all the relevant reaction paths to which TST should be applied. This is a serious issue, as omitted transition pathways can have uncontrollable consequences on the simulated long-time kinetics. Over the last decade or so, we have been developing a new class of methods for treating the long-time dynamics in these complex, infrequent-event systems. Rather than trying to guess in advance what reaction pathways may be important, we return instead to a molecular dynamics treatment, in which the trajectory itself finds an appropriate way to escape from each state of the system. Since a direct integration of the trajectory would be limited to nanoseconds, while we are seeking to follow the system for much longer times, we modify the dynamics in some way to cause the first escape to happen much more quickly, thereby accelerating the dynamics. The key is to design the modified dynamics in a way that does as little damage as possible to the probability for escaping along a given pathway - i.e., we try to preserve the relative rate constants for the different possible escape paths out of the state. We can then use this modified dynamics to follow the system from state to state, reaching much longer times than we could reach with direct MD. The dynamics within any one state may no longer be meaningful, but the state-to-state dynamics, in the best case, as we discuss in the paper, can be exact. We have developed three methods in this accelerated molecular dynamics (AMD) class, in each case appealing to TST, either implicitly or explicitly, to design the modified dynamics. Each of these methods has its own advantages, and we and others have applied these methods to a wide range of problems. The purpose of this article is to give the reader a brief introduction to how these methods work, and discuss some of the recent developments that have been made to improve their power and applicability. Note that this brief review does not claim to be exhaustive: various other methods aiming at similar goals have been proposed in the literature. For the sake of brevity, our focus will exclusively be on the methods developed by the group.

  16. Polycarbonate Simulations with a Density Functional Based Force Field P. Ballone, B. Montanari, and R. O. Jones*

    E-Print Network [OSTI]

    Polycarbonate Simulations with a Density Functional Based Force Field P. Ballone, B. Montanari properties of molecules related to polycarbonate have been used to optimize the parameters describing dynamics simulations of crystalline, amorphous, and liquid polycarbonate systems. Applications include

  17. PREDICTION OF CUTTINGS BED HEIGHT WITH COMPUTATIONAL FLUID DYNAMICS IN DRILLING HORIZONTAL AND HIGHLY DEVIATED WELLS

    E-Print Network [OSTI]

    Ullmer, Brygg

    PREDICTION OF CUTTINGS BED HEIGHT WITH COMPUTATIONAL FLUID DYNAMICS IN DRILLING HORIZONTAL parameters such as wellbore geometry, pump rate, drilling fluid rheology and density, and maximum drilling Computational Fluid Dynamics methods. Movement, concentration and accumulation of drilled cuttings in non

  18. Superfund record of decision (EPA Region 3): Patuxent River Naval Air Station, St. Mary`s County, MD, July 29, 1996

    SciTech Connect (OSTI)

    NONE

    1996-08-01T23:59:59.000Z

    The decision document presents the selected interim remedial action for Operable Unit 1 (OU1) of the Former Sanitary Landfill site, at the U.S. Naval Air Station Patuxent River, MD. The interim remedy will reduce the potential of human exposure to wastes remaining at the landfill, precipitation filtering through landfill waste, and the potential risk posed by inhalation and ingestion of contaminated surficial soil at the landfill. The interim action will allow for the continued investigation of the landfill while evaluating final remedial options for groundwater, surface water, and sediment at the site.

  19. Probability distribution of the vacuum energy density

    SciTech Connect (OSTI)

    Duplancic, Goran; Stefancic, Hrvoje [Theoretical Physics Division, Rudjer Boskovic Institute, P.O. Box 180, HR-10002 Zagreb (Croatia); Glavan, Drazen [Department of Physics, Faculty of Science, University of Zagreb, P.O. Box 331, HR-10002 Zagreb (Croatia)

    2010-12-15T23:59:59.000Z

    As the vacuum state of a quantum field is not an eigenstate of the Hamiltonian density, the vacuum energy density can be represented as a random variable. We present an analytical calculation of the probability distribution of the vacuum energy density for real and complex massless scalar fields in Minkowski space. The obtained probability distributions are broad and the vacuum expectation value of the Hamiltonian density is not fully representative of the vacuum energy density.

  20. Affine maps of density matrices

    E-Print Network [OSTI]

    Thomas F. Jordan

    2004-11-21T23:59:59.000Z

    For quantum systems described by finite matrices, linear and affine maps of matrices are shown to provide equivalent descriptions of evolution of density matrices for a subsystem caused by unitary Hamiltonian evolution in a larger system; an affine map can be replaced by a linear map, and a linear map can be replaced by an affine map. There may be significant advantage in using an affine map. The linear map is generally not completely positive, but the linear part of an equivalent affine map can be chosen to be completely positive and related in the simplest possible way to the unitary Hamiltonian evolution in the larger system.

  1. Rock Density | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are beingZealand Jump to:Ezfeedflag JumpID-f < RAPID‎ |Rippey Jump to: navigation, searchRobbinsDensity At

  2. Molecular dynamics study of salt–solution interface: Solubility and surface charge of salt in water

    SciTech Connect (OSTI)

    Kobayashi, Kazuya; Liang, Yunfeng, E-mail: y-liang@earth.kumst.kyoto-u.ac.jp, E-mail: matsuoka@earth.kumst.kyoto-u.ac.jp; Matsuoka, Toshifumi, E-mail: y-liang@earth.kumst.kyoto-u.ac.jp, E-mail: matsuoka@earth.kumst.kyoto-u.ac.jp [Environment and Resource System Engineering, Kyoto University, Kyoto 615-8540 (Japan)] [Environment and Resource System Engineering, Kyoto University, Kyoto 615-8540 (Japan); Sakka, Tetsuo [Department of Energy and Hydrocarbon Chemistry, Kyoto University, Kyoto 615-8510 (Japan)] [Department of Energy and Hydrocarbon Chemistry, Kyoto University, Kyoto 615-8510 (Japan)

    2014-04-14T23:59:59.000Z

    The NaCl salt–solution interface often serves as an example of an uncharged surface. However, recent laser-Doppler electrophoresis has shown some evidence that the NaCl crystal is positively charged in its saturated solution. Using molecular dynamics (MD) simulations, we have investigated the NaCl salt–solution interface system, and calculated the solubility of the salt using the direct method and free energy calculations, which are kinetic and thermodynamic approaches, respectively. The direct method calculation uses a salt–solution combined system. When the system is equilibrated, the concentration in the solution area is the solubility. In the free energy calculation, we separately calculate the chemical potential of NaCl in two systems, the solid and the solution, using thermodynamic integration with MD simulations. When the chemical potential of NaCl in the solution phase is equal to the chemical potential of the solid phase, the concentration of the solution system is the solubility. The advantage of using two different methods is that the computational methods can be mutually verified. We found that a relatively good estimate of the solubility of the system can be obtained through comparison of the two methods. Furthermore, we found using microsecond time-scale MD simulations that the positively charged NaCl surface was induced by a combination of a sodium-rich surface and the orientation of the interfacial water molecules.

  3. A molecular dynamics study of nuclear quantum effect on the diffusion of hydrogen in condensed phase

    SciTech Connect (OSTI)

    Nagashima, Hiroki; Tokumasu, Takashi [Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi (Japan); Tsuda, Shin-ichi [Shinshu University, 77-7 Minamibori, Nagano, Nagano (Japan); Tsuboi, Nobuyuki [Kyushu Institute of Technology, 1-1 Sensui-cho, Tobata-ku, Kitakyushu, Fukuoka (Japan); Koshi, Mitsuo [Yokohama National University, 79-7 Tokiwadai, Hodogaya, Yokohama, Kanagawa (Japan); Hayashie, A. Koichi [AoyamaGakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa (Japan)

    2014-10-06T23:59:59.000Z

    In this paper, the quantum effect of hydrogen molecule on its diffusivity is analyzed using Molecular Dynamics (MD) method. The path integral centroid MD (CMD) method is applied for the reproduction method of time evolution of the molecules. The diffusion coefficient of liquid hydrogen is calculated using the Green-Kubo method. The simulation is performed at wide temperature region and the temperature dependence of the quantum effect of hydrogen molecule is addressed. The calculation results are compared with those of classical MD results. As a result, it is confirmed that the diffusivity of hydrogen molecule is changed depending on temperature by the quantum effect. It is clarified that this result can be explained that the dominant factor by quantum effect on the diffusivity of hydrogen changes from the swollening the potential to the shallowing the potential well around 30 K. Moreover, it is found that this tendency is related to the temperature dependency of the ratio of the quantum kinetic energy and classical kinetic energy.

  4. High density behaviour of nuclear symmetry energy

    E-Print Network [OSTI]

    D. N. Basu; Tapan Mukhopadhyay

    2006-12-27T23:59:59.000Z

    Role of the isospin asymmetry in nuclei and neutron stars, with an emphasis on the density dependence of the nuclear symmetry energy, is discussed. The symmetry energy is obtained using the isoscalar as well as isovector components of the density dependent M3Y effective interaction. The constants of density dependence of the effective interaction are obtained by reproducing the saturation energy per nucleon and the saturation density of spin and isospin symmetric cold infinite nuclear matter. Implications for the density dependence of the symmetry energy in case of a neutron star are discussed, and also possible constraints on the density dependence obtained from finite nuclei are compared.

  5. Molecular dynamics simulation: a tool for exploration and discovery using simple models

    E-Print Network [OSTI]

    D. C. Rapaport

    2014-11-13T23:59:59.000Z

    Emergent phenomena share the fascinating property of not being obvious consequences of the design of the system in which they appear. This characteristic is no less relevant when attempting to simulate such phenomena, given that the outcome is not always a foregone conclusion. The present survey focuses on several simple model systems that exhibit surprisingly rich emergent behavior, all studied by MD simulation. The examples are taken from the disparate fields of fluid dynamics, granular matter and supramolecular self-assembly. In studies of fluids modeled at the detailed microscopic level using discrete particles, the simulations demonstrate that complex hydrodynamic phenomena in rotating and convecting fluids, the Taylor-Couette and Rayleigh-B\\'enard instabilities, can not only be observed within the limited length and time scales accessible to MD, but even quantitative agreement can be achieved. Simulation of highly counterintuitive segregation phenomena in granular mixtures, again using MD methods, but now augmented by forces producing damping and friction, leads to results that resemble experimentally observed axial and radial segregation in the case of a rotating cylinder, and to a novel form of horizontal segregation in a vertically vibrated layer. Finally, when modeling self-assembly processes analogous to the formation of the polyhedral shells that package spherical viruses, simulation of suitably shaped particles reveals the ability to produce complete, error-free assembly, and leads to the important general observation that reversible growth steps contribute to the high yield. While there are limitations to the MD approach, both computational and conceptual, the results offer a tantalizing hint of the kinds of phenomena that can be explored, and what might be discovered when sufficient resources are brought to bear on a problem.

  6. Subsystem real-time Time Dependent Density Functional Theory

    E-Print Network [OSTI]

    Krishtal, Alisa; Pavanello, Michele

    2015-01-01T23:59:59.000Z

    We present the extension of Frozen Density Embedding (FDE) theory to real-time Time Dependent Density Functional Theory (rt-TDDFT). FDE a is DFT-in-DFT embedding method that allows to partition a larger Kohn-Sham system into a set of smaller, coupled Kohn-Sham systems. Additional to the computational advantage, FDE provides physical insight into the properties of embedded systems and the coupling interactions between them. The extension to rt-TDDFT is done straightforwardly by evolving the Kohn-Sham subsystems in time simultaneously, while updating the embedding potential between the systems at every time step. Two main applications are presented: the explicit excitation energy transfer in real time between subsystems is demonstrated for the case of the Na$_4$ cluster and the effect of the embedding on optical spectra of coupled chromophores. In particular, the importance of including the full dynamic response in the embedding potential is demonstrated.

  7. Density waves in the shearing sheet I. Swing amplification

    E-Print Network [OSTI]

    B. Fuchs

    2001-03-02T23:59:59.000Z

    The shearing sheet model of a galactic disk is studied anew. The theoretical description of its dynamics is based on three building blocks: Stellar orbits, which are described here in epicyclic approximation, the collisionless Boltzmann equation determining the distribution function of stars in phase space, and the Poisson equation in order to take account of the self-gravity of the disk. Using these tools I develop a new formalism to describe perturbations of the shearing sheet. Applying this to the unbounded shearing sheet model I demonstrate again how the disturbances of the disk evolve always into `swing amplified' density waves, i.e. spiral-arm like, shearing density enhancements, which grow and decay while the wave crests swing by from leading to trailing orientation. Several examples are given how such `swing amplification' events are incited in the shearing sheet.

  8. Relativistic Coulomb excitation within Time Dependent Superfluid Local Density Approximation

    E-Print Network [OSTI]

    I. Stetcu; C. Bertulani; A. Bulgac; P. Magierski; K. J. Roche

    2015-01-13T23:59:59.000Z

    Within the framework of the unrestricted time-dependent density functional theory, we present for the first time an analysis of the relativistic Coulomb excitation of the heavy deformed open shell nucleus $^{238}$U. The approach is based on Superfluid Local Density Approximation (SLDA) formulated on a spatial lattice that can take into account coupling to the continuum, enabling self-consistent studies of superfluid dynamics of any nuclear shape. We have computed the energy deposited in the target nucleus as a function of the impact parameter, finding it to be significantly larger than the estimate using the Goldhaber-Teller model. The isovector giant dipole resonance, the dipole pygmy resonance and giant quadrupole modes were excited during the process. The one body dissipation of collective dipole modes is shown to lead a damping width $\\Gamma_\\downarrow \\approx 0.4$ MeV and the number of pre-equilibrium neutrons emitted has been quantified.

  9. Introduction Linear Dynamics

    E-Print Network [OSTI]

    Zeghib, Abdelghani

    Introduction Results Linear Dynamics Lorentz Dynamics Actions of discrete groups on stationary Piccione) Geodeycos Meeting, Lyon, 28-30 April 2010 Abdelghani Zeghib Dynamics on Lorentz manifolds #12;Introduction Results Linear Dynamics Lorentz Dynamics Motivations and questions Examples 1 Introduction

  10. Assumptions that imply quantum dynamics is linear

    E-Print Network [OSTI]

    Thomas F. Jordan

    2006-01-26T23:59:59.000Z

    A basic linearity of quantum dynamics, that density matrices are mapped linearly to density matrices, is proved very simply for a system that does not interact with anything else. It is assumed that at each time the physical quantities and states are described by the usual linear structures of quantum mechanics. Beyond that, the proof assumes only that the dynamics does not depend on anything outside the system but must allow the system to be described as part of a larger system. The basic linearity is linked with previously established results to complete a simple derivation of the linear Schrodinger equation. For this it is assumed that density matrices are mapped one-to-one onto density matrices. An alternative is to assume that pure states are mapped one-to-one onto pure states and that entropy does not decrease.

  11. Oxides having high energy densities

    DOE Patents [OSTI]

    Ceder, Gerbrand; Kang, Kisuk

    2013-09-10T23:59:59.000Z

    Certain disclosed embodiments generally relate to oxide materials having relatively high energy and/or power densities. Various aspects of the embodiments are directed to oxide materials having a structure B.sub.i(M.sub.jY.sub.k)O.sub.2, for example, a structure Li.sub.j(Ni.sub.jY.sub.k)O.sub.2 such as Li(Ni.sub.0.5Mn.sub.0.5)O.sub.2. In this structure, Y represents one or more atoms, each independently selected from the group consisting of alkaline earth metals, transition metals, Group 14 elements, Group 15, or Group 16 elements. In some embodiments, such an oxide material may have an O3 crystal structure, and/or a layered structure such that the oxide comprises a plurality of first, repeating atomic planes comprising Li, and a plurality of second, repeating atomic planes comprising Ni and/or Y.

  12. Collective dynamics of active filament complexes

    E-Print Network [OSTI]

    Nogucci, Hironobu

    2015-01-01T23:59:59.000Z

    Networks of biofilaments are essential for the formation of cellular structures and they support various biological functions. Previous studies have largely investigated the collective dynamics of rod-like biofilaments; however, the shapes of actual subcelluar componensts are often more elaborate. In this study, we investigated an active object composed of two active filaments, which represents a progression from rod-like biofilaments to complex-shaped biofilaments. Specifically, we numerically assessed the collective behaviors of these active objects and observed several types of dynamics depending on the density and the angle of the two filaments as shape parameters of the object. Among the observed collective dynamics, moving density bands that we named 'moving smectic' are reported here for the first time. By using statistical analyses of the orbits of individual objects and the interactions among them, the mechanisms underlying the rise of these dynamics patterns in the system were determined. This study...

  13. Enhanced molecular dynamics for simulating porous interphase layers in batteries.

    SciTech Connect (OSTI)

    Zimmerman, Jonathan A.; Wong, Bryan Matthew; Jones, Reese E.; Templeton, Jeremy Alan; Lee, Jonathan (Rice University, Houston, TX)

    2009-10-01T23:59:59.000Z

    Understanding charge transport processes at a molecular level using computational techniques is currently hindered by a lack of appropriate models for incorporating anistropic electric fields in molecular dynamics (MD) simulations. An important technological example is ion transport through solid-electrolyte interphase (SEI) layers that form in many common types of batteries. These layers regulate the rate at which electro-chemical reactions occur, affecting power, safety, and reliability. In this work, we develop a model for incorporating electric fields in MD using an atomistic-to-continuum framework. This framework provides the mathematical and algorithmic infrastructure to couple finite element (FE) representations of continuous data with atomic data. In this application, the electric potential is represented on a FE mesh and is calculated from a Poisson equation with source terms determined by the distribution of the atomic charges. Boundary conditions can be imposed naturally using the FE description of the potential, which then propagates to each atom through modified forces. The method is verified using simulations where analytical or theoretical solutions are known. Calculations of salt water solutions in complex domains are performed to understand how ions are attracted to charged surfaces in the presence of electric fields and interfering media.

  14. Protein synthesis driven by dynamical stochastic transcription

    E-Print Network [OSTI]

    Guilherme C. P. Innocentini; Michael Forger; Fernando Antoneli

    2014-12-23T23:59:59.000Z

    In this letter we propose a mathematical framework to couple transcription and translation in which mRNA production is described by a set of master equations while the dynamics of protein density is governed by a random differential equation. The coupling between the two processes is given by a stochastic perturbation whose statistics satisfies the master equations. In this approach, from the knowledge of the analytical time dependent distribution of mRNA number, we are able to calculate the dynamics of the probability density of the protein population.

  15. Decoherence rates for Galilean covariant dynamics

    E-Print Network [OSTI]

    Jeremy Clark

    2008-04-02T23:59:59.000Z

    We introduce a measure of decoherence for a class of density operators. For Gaussian density operators in dimension one it coincides with an index used by Morikawa (1990). Spatial decoherence rates are derived for three large classes of the Galilean covariant quantum semigroups introduced by Holevo. We also characterize the relaxation to a Gaussian state for these dynamics and give a theorem for the convergence of the Wigner function to the probability distribution of the classical analog of the process.

  16. Quantum critical benchmark for density functional theory

    E-Print Network [OSTI]

    Paul E. Grabowski; Kieron Burke

    2014-08-09T23:59:59.000Z

    Two electrons at the threshold of ionization represent a severe test case for electronic structure theory. A pseudospectral method yields a very accurate density of the two-electron ion with nuclear charge close to the critical value. Highly accurate energy components and potentials of Kohn-Sham density functional theory are given, as well as a useful parametrization of the critical density. The challenges for density functional approximations and the strength of correlation are also discussed.

  17. Lipoprotein subclass analysis by immunospecific density

    E-Print Network [OSTI]

    Lester, Sandy Marie

    2009-05-15T23:59:59.000Z

    to obtain a lipoprotein density profile in the absence and presence of apo C-1. Density Lipoprotein Profiling (DLP) gives relevant information of lipoproteins, such as density and subclass characterization, and is a novel approach to purify apo C-1-enriched...

  18. Ultimate Energy Densities for Electromagnetic Pulses

    E-Print Network [OSTI]

    Mankei Tsang

    2008-03-06T23:59:59.000Z

    The ultimate electric and magnetic energy densities that can be attained by bandlimited electromagnetic pulses in free space are calculated using an ab initio quantized treatment, and the quantum states of electromagnetic fields that achieve the ultimate energy densities are derived. The ultimate energy densities also provide an experimentally accessible metric for the degree of localization of polychromatic photons.

  19. Jacek Dobaczewski Density functional theory and energy

    E-Print Network [OSTI]

    Dobaczewski, Jacek

    in Poland per voivodship Energy density functional 245 647 Price voivodship functional 654 763 295 580Jacek Dobaczewski Density functional theory and energy density functionals in nuclear physics Jacek://www.fuw.edu.pl/~dobaczew/Stellenbosch/dobaczewski_lecture.pdf Home page: http://www.fuw.edu.pl/~dobaczew/ #12;Jacek Dobaczewski Nuclear Structure Energy scales

  20. The Critical Density and the Effective Excitation Density of Commonly Observed Molecular Dense Gas Tracers

    E-Print Network [OSTI]

    Shirley, Yancy L

    2015-01-01T23:59:59.000Z

    The optically thin critical densities and the effective excitation densities to produce a 1 K km/s (or 0.818 Jy km/s $(\\frac{\

  1. "Dark energy" as conformal dynamics of space

    E-Print Network [OSTI]

    D. Burlankov

    2006-10-23T23:59:59.000Z

    The exact solution for dynamic of conform-flat space homogeneous since dynamic equation is given. Conform mode of space metric changing in Global time theory has negative energy density. Swap of energy to this mode from another ones lead to increasing of Universe homogeneity although probability of this swap from local objects is negligibly small. Conform mode is corresponding to "dark energy" in observation astronomy.

  2. Aerodynamic Focusing Of High-Density Aerosols

    SciTech Connect (OSTI)

    Ruiz, D. E.; Fisch, Nathaniel

    2014-02-24T23:59:59.000Z

    High-density micron-sized particle aerosols might form the basis for a number of applications in which a material target with a particular shape might be quickly ionized to form a cylindrical or sheet shaped plasma. A simple experimental device was built in order to study the properties of high-density aerosol focusing for 1#22; m silica spheres. Preliminary results recover previous findings on aerodynamic focusing at low densities. At higher densities, it is demonstrated that the focusing properties change in a way which is consistent with a density dependent Stokes number.

  3. Statistical density modification using local pattern matching

    SciTech Connect (OSTI)

    Terwilliger, Thomas C., E-mail: terwilliger@lanl.gov [Mail Stop M888, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2003-10-01T23:59:59.000Z

    Statistical density modification can make use of local patterns of density found in protein structures to improve crystallographic phases. A method for improving crystallographic phases is presented that is based on the preferential occurrence of certain local patterns of electron density in macromolecular electron-density maps. The method focuses on the relationship between the value of electron density at a point in the map and the pattern of density surrounding this point. Patterns of density that can be superimposed by rotation about the central point are considered equivalent. Standard templates are created from experimental or model electron-density maps by clustering and averaging local patterns of electron density. The clustering is based on correlation coefficients after rotation to maximize the correlation. Experimental or model maps are also used to create histograms relating the value of electron density at the central point to the correlation coefficient of the density surrounding this point with each member of the set of standard patterns. These histograms are then used to estimate the electron density at each point in a new experimental electron-density map using the pattern of electron density at points surrounding that point and the correlation coefficient of this density to each of the set of standard templates, again after rotation to maximize the correlation. The method is strengthened by excluding any information from the point in question from both the templates and the local pattern of density in the calculation. A function based on the origin of the Patterson function is used to remove information about the electron density at the point in question from nearby electron density. This allows an estimation of the electron density at each point in a map, using only information from other points in the process. The resulting estimates of electron density are shown to have errors that are nearly independent of the errors in the original map using model data and templates calculated at a resolution of 2.6 Å. Owing to this independence of errors, information from the new map can be combined in a simple fashion with information from the original map to create an improved map. An iterative phase-improvement process using this approach and other applications of the image-reconstruction method are described and applied to experimental data at resolutions ranging from 2.4 to 2.8 Å.

  4. Ratcheting of driven attracting colloidal particles: Temporal density oscillations and current multiplicity

    E-Print Network [OSTI]

    Andrey Pototsky; Andrew J. Archer; Sergey E. Savel'ev; Uwe Thiele; Fabio Marchesoni

    2011-03-15T23:59:59.000Z

    We consider the unidirectional particle transport in a suspension of colloidal particles which interact with each other via a pair potential having a hard-core repulsion plus an attractive tail. The colloids are confined within a long narrow channel and are driven along by a DC or an AC external potential. In addition, the walls of the channel interact with the particles via a ratchet-like periodic potential. We use dynamical density functional theory to compute the average particle current. In the case of DC drive, we show that as the attraction strength between the colloids is increased beyond a critical value, the stationary density distribution of the particles loses its stability leading to depinning and a time dependent density profile. Attraction induced symmetry breaking gives rise to the coexistence of stable stationary density profiles with different spatial periods and time-periodic density profiles, each characterized by different values for the particle current.

  5. The Second Peak: The Dark-Energy Density and the Cosmic Microwave Background

    E-Print Network [OSTI]

    Marc Kamionkowski; Ari Buchalter

    2000-01-05T23:59:59.000Z

    Supernova evidence for a negative-pressure dark energy (e.g., cosmological constant or quintessence) that contributes a fraction $\\Omega_\\Lambda\\simeq0.7$ of closure density has been bolstered by the discrepancy between the total density, $\\Omega_{\\rm tot}\\simeq1$, suggested by the location of the first peak in the cosmic microwave background (CMB) power spectrum and the nonrelativistic-matter density $\\Omega_m\\simeq0.3$ obtained from dynamical measurements. Here we show that the impending identification of the location of the {\\it second} peak in the CMB power spectrum will provide an immediate and independent probe of the dark-energy density. As an aside, we show how the measured height of the first peak probably already points toward a low matter density and places upper limits to the reionization optical depth and gravitational-wave amplitude.

  6. Study of $^{64}$Ni+$^{132}$Sn Fusion with Density Constrained TDHF Formalism

    E-Print Network [OSTI]

    A. S. Umar; V. E. Oberacker

    2007-05-09T23:59:59.000Z

    We study fusion reactions of the $^{64}$Ni+$^{132}$Sn system using the recently introduced density constrained time-dependent Hartree-Fock formalism. In this formalism the fusion barriers are directly obtained from TDHF dynamics. In addition, we incorporate the entrance channel alignment of the deformed (oblate) $^{64}$Ni nucleus due to dynamical Coulomb excitation. We discuss the influence of particle transfer and other dynamical effects on the fusion cross sections. Calculated cross sections are in very good agreement with data and other calculations.

  7. Jump conditions and dynamic surface tension at permeable interfaces such as the inner core boundary

    E-Print Network [OSTI]

    Jump conditions and dynamic surface tension at permeable interfaces such as the inner core boundary as the density and viscosity changes. Independently of any intrinsic surface tension, a dynamic surface tension, a possibly anisotropic surface tension and terms including an interface mass density. In pratice

  8. A Density Functional Theory Study of Hydrogen Adsorption in MOF-5 Tim Mueller and Gerbrand Ceder*

    E-Print Network [OSTI]

    Ceder, Gerbrand

    . The effect of the framework on the physical structure and electronic structure of the organic linker initio molecular dynamics in the generalized gradient approximation to density functional theory, and calculations indicate that the sites with the strongest interaction with hydrogen are located near the Zn4O

  9. Potassium permeation through the KcsA channel: a density functional study

    E-Print Network [OSTI]

    Guidoni, Leonardo

    ; Streptomyces lividans; Ab initio electronic structure calculation; Ionic selectivity; Electronic polarization of the electronic structure for potassium permeation, we have here under- taken a first principles Density-Parrinello Molecular Dynamics [19] and hybrid CPMD/MM calculations [20]. Our investigation is carried out in two steps

  10. Dynamical clustering of counterions on flexible polyelectrolytes

    E-Print Network [OSTI]

    Tak Shing Lo; Boris Khusid; Joel Koplik

    2007-07-31T23:59:59.000Z

    Molecular dynamics simulations are used to study the local dynamics of counterion-charged polymer association at charge densities above and below the counterion condensation threshold. Surprisingly, the counterions form weakly-interacting clusters which exhibit short range orientational order, and which decay slowly due to migration of ions across the diffuse double layer. The cluster dynamics are insensitive to an applied electric field, and qualitatively agree with the available experimental data. The results are consistent with predictions of the classical theory only over much longer time scales.

  11. Dynamical models with a general anisotropy profile

    E-Print Network [OSTI]

    M. Baes; E. Van Hese

    2007-05-28T23:59:59.000Z

    Both numerical simulations and observational evidence indicate that the outer regions of galaxies and dark matter haloes are typically mildly to significantly radially anisotropic. The inner regions can be significantly non-isotropic, depending on the dynamical formation and evolution processes. In an attempt to break the lack of simple dynamical models that can reproduce this behaviour, we explore a technique to construct dynamical models with an arbitrary density and an arbitrary anisotropy profile. We outline a general construction method and propose a more practical approach based on a parameterized anisotropy profile. This approach consists of fitting the density of the model with a set of dynamical components, each of which have the same anisotropy profile. Using this approach we avoid the delicate fine-tuning difficulties other fitting techniques typically encounter when constructing radially anisotropic models. We present a model anisotropy profile that generalizes the Osipkov-Merritt profile, and that can represent any smooth monotonic anisotropy profile. Based on this model anisotropy profile, we construct a very general seven-parameter set of dynamical components for which the most important dynamical properties can be calculated analytically. We use the results to look for simple one-component dynamical models that generate simple potential-density pairs while still supporting a flexible anisotropy profile. We present families of Plummer and Hernquist models in which the anisotropy at small and large radii can be chosen as free parameters. We also generalize these two families to a three-parameter family that self-consistently generates the set of Veltmann potential-density pairs. (Abridged...)

  12. Why quantum dynamics is linear

    E-Print Network [OSTI]

    Thomas F. Jordan

    2007-02-16T23:59:59.000Z

    Quantum dynamics is linear. How do we know? From theory or experiment? The history of this question is reviewed. Nonlinear generalizations of quantum mechanics have been proposed. They predict small but clear nonlinear effects, which very accurate experiments have not seen. Is there a reason in principle why nonlinearity is not found? Is it impossible? Does quantum dynamics have to be linear? Attempts to prove this have not been decisive, because either their assumptions are not compelling or their arguments are not conclusive. The question has been left unsettled. There is a simple answer, based on a simple assumption. It was found in two steps separated by 44 years. They are steps back to simpler and more compelling assumptions. A proof of the assumptions of the Wigner-Bargmann proof has been known since 1962. It assumes that the maps of density matrices in time are linear. For this step, it is also assumed that density matrices are mapped one-to-one onto density matrices. An alternative is to assume that pure states are mapped one-to-one onto pure states and that entropy does not decrease. In a step taken in 2006, it is proved that the maps of density matrices in time are linear. It is assumed, as in the earlier step, that at each time the physical quantities and states are described by the usual linear structures of quantum mechanics, so the question is only about how things change in time. Beyond that, the proof assumes only that the dynamics does not depend on anything outside the system, but must allow the system to be described as part of a larger system.

  13. Isomorphic classical molecular dynamics model for an excess electronin a supercritical fluid

    SciTech Connect (OSTI)

    Miller III, Thomas F.

    2008-08-04T23:59:59.000Z

    Ring polymer molecular dynamics (RPMD) is used to directly simulate the dynamics of an excess electron in a supercritical fluid over a broad range of densities. The accuracy of the RPMD model is tested against numerically exact path integral statistics through the use of analytical continuation techniques. At low fluid densities, the RPMD model substantially underestimates the contribution of delocalized states to the dynamics of the excess electron. However, with increasing solvent density, the RPMD model improves, nearly satisfying analytical continuation constraints at densities approaching those of typical liquids. In the high density regime, quantum dispersion substantially decreases the self-diffusion of the solvated electron. In this regime where the dynamics of the electron is strongly coupled to the dynamics of the atoms in the fluid, trajectories that can reveal diffusive motion of the electron are long in comparison to {beta}{h_bar}.

  14. Molecular dynamics studies of the primary state of radiation damage

    SciTech Connect (OSTI)

    Diaz de la Rubia, T.; Averback, R.S.; Robertson, I.M.; Benedek, R.

    1988-12-01T23:59:59.000Z

    This paper summarizes recent progress in the understanding of energetic displacement cascades in metals achieved with the molecular-dynamics (MD) simulation technique. Recoil events with primary-knock-on-atom (PKA) energies up to 5 keV were simulated in Cu and Ni. The initial development of displacement cascades was similar in both metals, with replacement collision sequences providing the most efficient mechanism for the separation of interstitials and vacancies. The thermal-spike behavior in these metals, however, is quite different; Cu cascades are characterized by lower defect production and greater atomic disordering than those in Ni. The thermal spike significantly influences various other properties of cascades, such as total defect production and defect clustering. 32 refs., 7 figs., 2 tabs.

  15. Quartz resonator fluid density and viscosity monitor

    DOE Patents [OSTI]

    Martin, Stephen J. (Albuquerque, NM); Wiczer, James J. (Albuquerque, NM); Cernosek, Richard W. (Albuquerque, NM); Frye, Gregory C. (Cedar Crest, NM); Gebert, Charles T. (Albuquerque, NM); Casaus, Leonard (Bernalillo, NM); Mitchell, Mary A. (Tijeras, NM)

    1998-01-01T23:59:59.000Z

    A pair of thickness-shear mode resonators, one smooth and one with a textured surface, allows fluid density and viscosity to be independently resolved. A textured surface, either randomly rough or regularly patterned, leads to trapping of liquid at the device surface. The synchronous motion of this trapped liquid with the oscillating device surface allows the device to weigh the liquid; this leads to an additional response that depends on liquid density. This additional response enables a pair of devices, one smooth and one textured, to independently resolve liquid density and viscosity; the difference in responses determines the density while the smooth device determines the density-viscosity product, and thus, the pair determines both density and viscosity.

  16. Densities and viscosities of ternary ammonia/water fluids

    SciTech Connect (OSTI)

    Reiner, R.H.; Zaltash, A.

    1993-03-01T23:59:59.000Z

    The densities, viscosities, and boiling points (at barometric pressure) of solutions formed by inorganic salts dissolved in an ammonia/water (NH{sub 3}/H{sub 2}O) solvent have been measured. These ternary solutions of ammonia/water/dissolved salt are being investigated to reduce rectification requirements and to expand the temperature range of ammonia/water in advanced absorption cycles. Densities and viscosities of these fluids were measured over the temperature range of 283.15 to 343.15 K (10.0 to 70.0{degrees}C). Observed densities and viscosities were expressed as empirical functions of temperature by means of the least-squares method. The dynamic viscosities of ternary fluids were found to be three to seven times greater than those of the binary system of NH{sub 3}/H{sub 2}O, which implies that a substantial decrease in the film heat and mass transfer coefficient is possible. However, because this quantitative linkage is not well understood, direct measurements of heat and mass transfer rates in a minisorber are recommended and planned.

  17. Combined 3D-QSAR, molecular docking and molecular dynamics study on thyroid hormone activity of hydroxylated polybrominated diphenyl ethers to thyroid receptors ?

    SciTech Connect (OSTI)

    Li, Xiaolin [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046 (China)] [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046 (China); Ye, Li [Suzhou NeuPharma Co.,Ltd, Suzhou 215123 (China)] [Suzhou NeuPharma Co.,Ltd, Suzhou 215123 (China); Wang, Xiaoxiang [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046 (China)] [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046 (China); Wang, Xinzhou [Suzhou NeuPharma Co.,Ltd, Suzhou 215123 (China)] [Suzhou NeuPharma Co.,Ltd, Suzhou 215123 (China); Liu, Hongling [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046 (China)] [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046 (China); Zhu, Yongliang [Suzhou NeuPharma Co.,Ltd, Suzhou 215123 (China)] [Suzhou NeuPharma Co.,Ltd, Suzhou 215123 (China); Yu, Hongxia, E-mail: hongxiayu01@yahoo.com.cn [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046 (China)] [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046 (China)

    2012-12-15T23:59:59.000Z

    Several recent reports suggested that hydroxylated polybrominated diphenyl ethers (HO-PBDEs) may disturb thyroid hormone homeostasis. To illuminate the structural features for thyroid hormone activity of HO-PBDEs and the binding mode between HO-PBDEs and thyroid hormone receptor (TR), the hormone activity of a series of HO-PBDEs to thyroid receptors ? was studied based on the combination of 3D-QSAR, molecular docking, and molecular dynamics (MD) methods. The ligand- and receptor-based 3D-QSAR models were obtained using Comparative Molecular Similarity Index Analysis (CoMSIA) method. The optimum CoMSIA model with region focusing yielded satisfactory statistical results: leave-one-out cross-validation correlation coefficient (q{sup 2}) was 0.571 and non-cross-validation correlation coefficient (r{sup 2}) was 0.951. Furthermore, the results of internal validation such as bootstrapping, leave-many-out cross-validation, and progressive scrambling as well as external validation indicated the rationality and good predictive ability of the best model. In addition, molecular docking elucidated the conformations of compounds and key amino acid residues at the docking pocket, MD simulation further determined the binding process and validated the rationality of docking results. -- Highlights: ? The thyroid hormone activities of HO-PBDEs were studied by 3D-QSAR. ? The binding modes between HO-PBDEs and TR? were explored. ? 3D-QSAR, molecular docking, and molecular dynamics (MD) methods were performed.

  18. Fatal self-poisoning with lithium carbonate M.R. Achong, b sc, mb; P.G. Fernandez, mrcp, frcp[c]; P.J. McLeod, md, frcp[c

    E-Print Network [OSTI]

    Laughlin, Robert B.

    Fatal self-poisoning with lithium carbonate M.R. Achong, b sc, mb; P.G. Fernandez, mrcp, frcp[c]; P.J. McLeod, md, frcp[c] Summary: In a fatal case of self- poisoning with lithium carbonate

  19. Heart DiseaseHeart Disease--Learn to Love YourLearn to Love Your Michael McKee, M.D.Michael McKee, M.D.

    E-Print Network [OSTI]

    Goldman, Steven A.

    Heart DiseaseHeart Disease-- Learn to Love YourLearn to Love Your HeartHeart Michael McKee, M.D.Michael McKee, M.D. March 19, 2010March 19, 2010 #12;GoalsGoals ·· Learn more about heart disease for yourself andLearn more about heart disease for yourself and for your studentsfor your students ·· Learn

  20. Reduce Building Energy Consumption by Improving the Supply Air Temperature Schedule and Recommissioning the Terminal Boxes, Submitted to the Energy Management and Operations Division at the M.D. Anderson Cancer Center

    E-Print Network [OSTI]

    Liu, M.; Athar, A.; Zhu, Y.; Claridge, D. E.

    1995-01-01T23:59:59.000Z

    At the request of the Energy Management and Operations Department at M.D. Anderson Cancer Center, the Energy Systems Laboratory of Texas A&M University performed a study of optimizing the HVAC operation at its Basic Research Building. The Basic...

  1. M.D. Lemmon, Xiaojun Yang and P. J. Antsaklis, "Inductive Inference of Logical DES Controllers using the L* Algorithm," Technical Report of the ISIS (Interdisciplinary Studies of Intelligent Systems)

    E-Print Network [OSTI]

    Antsaklis, Panos

    using the L* Algorithm," Technical Report of the ISIS (Interdisciplinary Studies of Intelligent Systems) Group, No. ISIS-94-010, Univ of Notre Dame, September 1994. #12;M.D. Lemmon, Xiaojun Yang and P. J of the ISIS (Interdisciplinary Studies of Intelligent Systems) Group, No. ISIS-94-010, Univ of Notre Dame

  2. Introduction to Dynamic Distributed

    E-Print Network [OSTI]

    Roma "La Sapienza", Università di

    Introduction to Dynamic Distributed SystemsSystems #12;Outline Introduction Churn Building Applications in Dynamic Distributed Systems RegistersRegisters Eventual Leader election Connectivity in Dynamic Distributed Systems #12;Dynamic Distributed Systems: Context & Motivations Advent of Complex Distributed

  3. Method of synthesizing a low density material

    DOE Patents [OSTI]

    Lorensen, L.E.; Monaco, S.B.

    1987-02-27T23:59:59.000Z

    A novel method of synthesizing a polymeric material of low density of the order of 50mg/cc or less. Such a low density material has applications in many areas including laser target fabrication. The method comprises preparing a polymer blend of two incompatible polymers as a major and a minor phase by mixing them and extruding the mixture, and then selectively extracting the major component, to yield a fine, low density structure.

  4. Considering Air Density in Wind Power Production

    E-Print Network [OSTI]

    Zénó Farkas

    2011-03-11T23:59:59.000Z

    In the wind power production calculations the air density is usually considered as constant in time. Using the CIPM-2007 equation for the density of moist air as a function of air temperature, air pressure and relative humidity, we show that it is worth taking the variation of the air density into account, because higher accuracy can be obtained in the calculation of the power production for little effort.

  5. Considering Air Density in Wind Power Production

    E-Print Network [OSTI]

    Farkas, Zénó

    2011-01-01T23:59:59.000Z

    In the wind power production calculations the air density is usually considered as constant in time. Using the CIPM-2007 equation for the density of moist air as a function of air temperature, air pressure and relative humidity, we show that it is worth taking the variation of the air density into account, because higher accuracy can be obtained in the calculation of the power production for little effort.

  6. On the Extensive Air Shower density spectrum

    E-Print Network [OSTI]

    Aleksander Zawadzki; Tadeusz Wibig; Jerzy Gawin

    1998-07-29T23:59:59.000Z

    In search for new methods of determining the primary energy spectrum of Cosmic Rays, the attention was paid to the density spectrum measurement. New methods available at present warrant an accurateness of conclusions derived from the density spectrum measurements. The general statement about the change of the spectral index of the charged particle density spectrum is confirmed very clearly. Results concerning the shower size and primary energy spectra are also presented and discussed. Interesting future prospects for applications of the density spectrum method are proposed.

  7. Lipoprotein subclass analysis by immunospecific density 

    E-Print Network [OSTI]

    Lester, Sandy Marie

    2009-05-15T23:59:59.000Z

    ] 6 Table 1: Composition of Human Serum Lipoproteins Component Chylomicrons VLDL IDL LDL HDL Phospholipids (Weight %) 6-9 16-20 20-24 24-30 24-30 Free Cholesterol (Weight %) 1-3 4-8 8-9 9-12 2-5 Cholesteryl Esters (Weight %) 3-6 9... lipase; IDL, intermediate-density lipoprotein; LCAT, lecithin-cholesterol acyltransferase; LDL, low-density lipoprotein; LDL-R, low-density lipoprotein receptor; LDL-RRP, low-density lipoprotein receptor-related protein; Lyso PC...

  8. 3-D capacitance density imaging system

    DOE Patents [OSTI]

    Fasching, G.E.

    1988-03-18T23:59:59.000Z

    A three-dimensional capacitance density imaging of a gasified bed or the like in a containment vessel is achieved using a plurality of electrodes provided circumferentially about the bed in levels and along the bed in channels. The electrodes are individually and selectively excited electrically at each level to produce a plurality of current flux field patterns generated in the bed at each level. The current flux field patterns are suitably sensed and a density pattern of the bed at each level determined. By combining the determined density patterns at each level, a three-dimensional density image of the bed is achieved. 7 figs.

  9. Flavor Dynamics

    E-Print Network [OSTI]

    Michael Murray; for the BRAHMS Collaboration

    2007-10-24T23:59:59.000Z

    The purpose of BRAHMS is to survey the dynamics of relativistic heavy ion (as well as pp and d-A) collisions over a very wide range of rapidity and transverse momentum. The sum of these data may give us a glimpse of the initial state of the system, its transverse and longitudinal evolution and how the nature of the system changes with time. Here I will concentrate on the origin and dynamics of the light flavors, i.e. the creation and transport of the up, down and strange quarks. The results presented here are certainly not the end of the story. It is my hope that in a few years new detectors will reveal the rapidity dependence of the charm and bottom quarks.

  10. Level dynamics and the ten-fold way

    E-Print Network [OSTI]

    Alan T. Huckleberry; Marek Kus; Patrick Schuetzdeller

    2007-02-25T23:59:59.000Z

    We investigate the parameter dynamics of eigenvalues of Hamiltonians ('level dynamics') defined on symmetric spaces relevant for condensed matter and particle physics. In particular we: 1) identify appropriate reduced manifold on which the motion takes place, 2) identify the correct Poisson structure ensuring the Hamiltonian character of the reduced dynamics, 3) determine the canonical measure on the reduced space, 4) calculate the resulting eigenvalue density.

  11. aerial density profiles: Topics by E-print Network

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

    present an analytic approach to predict gas density and temperature profiles in dark matter haloes. We assume that the gas density profile traces the dark matter density profile...

  12. High density laser-driven target

    DOE Patents [OSTI]

    Lindl, John D. (San Ramon, CA)

    1981-01-01T23:59:59.000Z

    A high density target for implosion by laser energy composed of a central quantity of fuel surrounded by a high-Z pusher shell with a low-Z ablator-pusher shell spaced therefrom forming a region filled with low-density material.

  13. Neutral depletion and the helicon density limit

    SciTech Connect (OSTI)

    Magee, R. M.; Galante, M. E.; Carr, J. Jr.; Lusk, G.; McCarren, D. W.; Scime, E. E. [West Virginia University, Morgantown, West Virginia 26506 (United States)] [West Virginia University, Morgantown, West Virginia 26506 (United States)

    2013-12-15T23:59:59.000Z

    It is straightforward to create fully ionized plasmas with modest rf power in a helicon. It is difficult, however, to create plasmas with density >10{sup 20} m{sup ?3}, because neutral depletion leads to a lack of fuel. In order to address this density limit, we present fast (1 MHz), time-resolved measurements of the neutral density at and downstream from the rf antenna in krypton helicon plasmas. At the start of the discharge, the neutral density underneath the antenna is reduced to 1% of its initial value in 15 ?s. The ionization rate inferred from these data implies that the electron temperature near the antenna is much higher than the electron temperature measured downstream. Neutral density measurements made downstream from the antenna show much slower depletion, requiring 14 ms to decrease by a factor of 1/e. Furthermore, the downstream depletion appears to be due to neutral pumping rather than ionization.

  14. Density functional theory for carbon dioxide crystal

    SciTech Connect (OSTI)

    Chang, Yiwen; Mi, Jianguo, E-mail: mijg@mail.buct.edu.cn; Zhong, Chongli [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China)

    2014-05-28T23:59:59.000Z

    We present a density functional approach to describe the solid?liquid phase transition, interfacial and crystal structure, and properties of polyatomic CO{sub 2}. Unlike previous phase field crystal model or density functional theory, which are derived from the second order direct correlation function, the present density functional approach is based on the fundamental measure theory for hard-sphere repulsion in solid. More importantly, the contributions of enthalpic interactions due to the dispersive attractions and of entropic interactions arising from the molecular architecture are integrated in the density functional model. Using the theoretical model, the predicted liquid and solid densities of CO{sub 2} at equilibrium triple point are in good agreement with the experimental values. Based on the structure of crystal-liquid interfaces in different planes, the corresponding interfacial tensions are predicted. Their respective accuracies need to be tested.

  15. Nanoscale density fluctuations in swift heavy ion irradiated amorphous SiO{sub 2}

    SciTech Connect (OSTI)

    Kluth, P.; Giulian, R.; Ridgway, M. C. [Department of Electronic Materials Engineering, Australian National University, Canberra ACT 0200 (Australia); Pakarinen, O. H.; Djurabekova, F.; Nordlund, K. [Department of Physics and Helsinki Institute of Physics, University of Helsinki, Helsinki (Finland); Byrne, A. P. [Department of Nuclear Physics, Australian National University, Canberra ACT 0200 (Australia)

    2011-12-15T23:59:59.000Z

    We report on the observation of nanoscale density fluctuations in 2 {mu}m thick amorphous SiO{sub 2} layers irradiated with 185 MeV Au ions. At high fluences, in excess of approximately 5 x 10{sup 12} ions/cm{sup 2}, where the surface is completely covered by ion tracks, synchrotron small angle x-ray scattering measurements reveal the existence of a steady state of density fluctuations. In agreement with molecular dynamics simulations, this steady state is consistent with an ion track ''annihilation'' process, where high-density regions generated in the periphery of new tracks fill in low-density regions located at the center of existing tracks.

  16. Theory for planetary exospheres: II. Radiation pressure effect on exospheric density profiles

    E-Print Network [OSTI]

    Beth, Arnaud; Toublanc, Dominique; Dandouras, Iannis; Mazelle, Christian

    2015-01-01T23:59:59.000Z

    The planetary exospheres are poorly known in their outer parts, since the neutral densities are low compared with the instruments detection capabilities. The exospheric models are thus often the main source of information at such high altitudes. We present a new way to take into account analytically the additional effect of the radiation pressure on planetary exospheres. In a series of papers, we present with an Hamiltonian approach the effect of the radiation pressure on dynamical trajectories, density profiles and escaping thermal flux. Our work is a generalization of the study by Bishop and Chamberlain (1989). In this second part of our work, we present here the density profiles of atomic Hydrogen in planetary exospheres subject to the radiation pressure. We first provide the altitude profiles of ballistic particles (the dominant exospheric population in most cases), which exhibit strong asymmetries that explain the known geotail phenomenon at Earth. The radiation pressure strongly enhances the densities c...

  17. Density waves in the shearing sheet IV. Interaction with a live dark halo

    E-Print Network [OSTI]

    B. Fuchs

    2004-03-01T23:59:59.000Z

    It is shown that if the self-gravitating shearing sheet, a model of a patch of a galactic disk, is embedded in a live dark halo, this has a strong effect on the dynamics of density waves in the sheet. I describe how the density waves and the halo interact via halo particles either on orbits in resonance with the wave or on non-resonant orbits. Contrary to expectation the presence of the halo leads to a very considerable enhancement of the amplitudes of the density waves in the shearing sheet. This effect appears to be the equivalent of the recently reported enhanced growth of bars in numerically simulated stellar disks embedded in live dark halos. Finally I discuss the transfer of linear momentum from a density wave in the sheet to the halo and show that it is mediated only by halo particles on resonant orbits.

  18. Density Prediction of Uranium-6 Niobium Ingots

    SciTech Connect (OSTI)

    D.F.Teter; P.K. Tubesing; D.J.Thoma; E.J.Peterson

    2003-04-15T23:59:59.000Z

    The densities of uranium-6 niobium (U-Nb) alloys have been compiled from a variety of literature sources such as Y-12 and Rocky Flats datasheets. We also took advantage of the 42 well-pedigreed, homogeneous baseline U-Nb alloys produced under the Enhanced Surveillance Program for density measurements. Even though U-Nb alloys undergo two-phase transitions as the Nb content varies from 0 wt. % to 8 wt %, the theoretical and measured densities vary linearly with Nb content. Therefore, the effect of Nb content on the density was modeled with a linear regression. From this linear regression, a homogeneous ingot of U-6 wt.% Nb would have a density of 17.382 {+-} 0.040 g/cc (95% CI). However, ingots produced at Y-12 are not homogeneous with respect to the Nb content. Therefore, using the 95% confidence intervals, the density of a Y-12 produced ingot would vary from 17.310 {+-} 0.043 g/cc at the center to 17.432 {+-} 0.039 g/cc at the edge. Ingots with larger Nb inhomogeneities will also have larger variances in the density.

  19. Periodic subsystem density-functional theory

    SciTech Connect (OSTI)

    Genova, Alessandro; Pavanello, Michele, E-mail: m.pavanello@rutgers.edu [Department of Chemistry, Rutgers University, Newark, New Jersey 07102 (United States); Ceresoli, Davide [Department of Chemistry, Rutgers University, Newark, New Jersey 07102 (United States); CNR-ISTM, Institute of Molecular Sciences and Technologies, Milano (Italy)

    2014-11-07T23:59:59.000Z

    By partitioning the electron density into subsystem contributions, the Frozen Density Embedding (FDE) formulation of subsystem Density Functional Theory (DFT) has recently emerged as a powerful tool for reducing the computational scaling of Kohn–Sham DFT. To date, however, FDE has been employed to molecular systems only. Periodic systems, such as metals, semiconductors, and other crystalline solids have been outside the applicability of FDE, mostly because of the lack of a periodic FDE implementation. To fill this gap, in this work we aim at extending FDE to treat subsystems of molecular and periodic character. This goal is achieved by a dual approach. On one side, the development of a theoretical framework for periodic subsystem DFT. On the other, the realization of the method into a parallel computer code. We find that periodic FDE is capable of reproducing total electron densities and (to a lesser extent) also interaction energies of molecular systems weakly interacting with metallic surfaces. In the pilot calculations considered, we find that FDE fails in those cases where there is appreciable density overlap between the subsystems. Conversely, we find FDE to be in semiquantitative agreement with Kohn–Sham DFT when the inter-subsystem density overlap is low. We also conclude that to make FDE a suitable method for describing molecular adsorption at surfaces, kinetic energy density functionals that go beyond the GGA level must be employed.

  20. Dynamic Correlation Length Scales under Isochronal Conditions

    E-Print Network [OSTI]

    R. Casalini; D. Fragiadakis; C. M. Roland

    2014-11-24T23:59:59.000Z

    The origin of the dramatic changes in the behavior of liquids as they approach their vitreous state - increases of many orders of magnitude in transport properties and dynamic time scales - is a major unsolved problem in condensed matter. These changes are accompanied by greater dynamic heterogeneity, which refers to both spatial variation and spatial correlation of molecular mobilities. The question is whether the changing dynamics is coupled to this heterogeneity; that is, does the latter cause the former? To address this we carried out the first nonlinear dielectric experiments at elevated hydrostatic pressures on two liquids, to measure the third-order harmonic component of their susceptibilities. We extract from this the number of dynamically correlated molecules for various state points, and find that the dynamic correlation volume for non-associated liquids depends primarily on the relaxation time, sensibly independent of temperature and pressure. We support this result by molecular dynamic simulations showing that the maximum in the four-point dynamic susceptibility of density fluctuations varies less than 10% for molecules that do not form hydrogen bonds. Our findings are consistent with dynamic heterogeneity serving as the principal control parameter for the slowing down of molecular motions in supercooled materials.

  1. Nuclear Dynamics at the Balance Energy

    E-Print Network [OSTI]

    Aman D. Sood; Rajeev K. Puri

    2003-11-05T23:59:59.000Z

    We study the mass dependence of various quantities (like the average and maximum density, collision rate, participant-spectator matter, temperature as well as time zones for higher density) by simulating the reactions at the energy of vanishing flow. This study is carried out within the framework of Quantum Molecular Dynamics model. Our findings clearly indicate an existence of a power law in all the above quantities calculated at the balance energy. The only significant mass dependence was obtained for the temperature reached in the central sphere. All other quantities are rather either insensitive or depend weakly on the system size at balance energy. The time zone for higher density as well as the time of maximal density and collision rate follow a power law inverse to the energy of vanishing flow.

  2. Dynamically Responsive Infrared Window Coatings

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn't Your Destiny:Revised Finding of No53197E TDrew Bittner About UsDurable, Low Cost,1Dynamically

  3. Dynamics of dendritic polymers in the bulk and under confinement

    SciTech Connect (OSTI)

    Chrissopoulou, K. [Foundation for Research and Technology-Hellas, Institute of Electronic Structure and Laser, P.O. Box 1527, 711 10, Heraklion Crete (Greece); Fotiadou, S. [Foundation for Research and Technology-Hellas, Institute of Electronic Structure and Laser, P.O. Box 1527, 711 10, Heraklion Crete, Greece and Aristotle University of Thessaloniki, Department of Chemical Engineering, Thessaloniki (Greece); Androulaki, K.; Anastasiadis, S. H. [Foundation for Research and Technology-Hellas, Institute of Electronic Structure and Laser, P.O. Box 1527, 711 10, Heraklion Crete, Greece and University of Crete, Department of Chemistry, Heraklion Crete (Greece); Tanis, I.; Karatasos, K. [Aristotle University of Thessaloniki, Department of Chemical Engineering, Thessaloniki (Greece); Prevosto, D.; Labardi, M. [CNR-IPCF, Department of Physics, University of Pisa, Pisa (Italy); Frick, B. [ILL-Institut Laue-Langevin, Grenoble (France)

    2014-05-15T23:59:59.000Z

    The structure and dynamics of a hyperbranched polyesteramide (Hybrane® S 1200) polymer and its nanocomposites with natural montmorillonite (Na{sup +}-MMT) are investigated by XRD, DSC, QENS, DS and Molecular Dynamics (MD) simulation. In bulk, the energy-resolved elastically scattered intensity from the polymer exhibits two relaxation steps, one attributed to sub-T{sub g} motions and one observed at temperatures above the glass transition, T{sub g}. The QENS spectra measured over the complete temperature range are consistent with the elastic measurements and can be correlated to the results emerging from the detailed description afforded by the atomistic simulations, which predict the existence of three relaxation processes. Moreover, dielectric spectroscopy shows the sub- T{sub g} beta process as well as the segmental relaxation. For the nanocomposites, XRD reveals an intercalated structure for all hybrids with distinct interlayer distances due to polymer chains residing within the galleries of the Na{sup +}-MMT. The polymer chains confined within the galleries show similarities in the behavior with that of the polymer in the bulk for temperatures below the bulk polymer T{sub g}, whereas they exhibit frozen dynamics under confinement at temperatures higher than that.

  4. The temperature dependence of equilibrium plasma density

    E-Print Network [OSTI]

    B. V. Vasiliev

    2002-03-17T23:59:59.000Z

    Temperature dependence of an electron-nuclear plasma equilibrium density is considered basing on known approaches, which are given in (1)(2). It is shown that at a very high temperature, which is characteristic for a star interior, the equilibrium plasma density is almost constant and equals approximately to $10^{25}$ particles per $cm^3$. At a relatively low temperature, which is characteristic for star surface, the equilibrium plasma density is in several orders lower and depends on temperature as $T^{3/2}$.

  5. Low density, resorcinol-formaldehyde aerogels

    DOE Patents [OSTI]

    Pekala, R.W.

    1988-05-26T23:59:59.000Z

    The polycondensation of resorcinol with formaldehyde under alkaline conditions results in the formation of surface functionalized polymer ''clusters''. The covalent crosslinking of these ''clusters'' produces gels which when processed under supercritical conditions, produce low density, organic aerogels (density less than or equal to100 mg/cc; cell size less than or equal to0.1 microns). The aerogels are transparent,dark red in color and consist of interconnected colloidal-like particles with diameters of about 100 A/degree/. These aerogels may be further carbonized to form low density carbon foams with cell size of about 0.1 micron. 1 fig., 1 tab.

  6. Low density, resorcinol-formaldehyde aerogels

    DOE Patents [OSTI]

    Pekala, R.W.

    1989-10-10T23:59:59.000Z

    The polycondensation of resorcinol with formaldehyde under alkaline conditions results in the formation of surface functionalized polymer clusters. The covalent crosslinking of these clusters produces gels which when processed under supercritical conditions, produce low density, organic aerogels (density [<=]100 mg/cc; cell size [<=]0.1 microns). The aerogels are transparent, dark red in color and consist of interconnected colloidal-like particles with diameters of about 100 [angstrom]. These aerogels may be further carbonized to form low density carbon foams with cell size of about 0.1 micron.

  7. Low density, resorcinol-formaldehyde aerogels

    SciTech Connect (OSTI)

    Pekala, Richard W. (Pleasant Hill, CA)

    1989-01-01T23:59:59.000Z

    The polycondensation of resorcinol with formaldehyde under alkaline conditions results in the formation of surface functionalized polymer "clusters". The covalent crosslinking of these "clusters" produces gels which when processed under supercritical conditions, produce low density, organic aerogels (density .ltoreq.100 mg/cc; cell size .ltoreq.0.1 microns). The aerogels are transparent, dark red in color and consist of interconnected colloidal-like particles with diameters of about 100 .ANG.. These aerogels may be further carbonized to form low density carbon foams with cell size of about 0.1 micron.

  8. Low density, resorcinol-formaldehyde aerogels

    DOE Patents [OSTI]

    Pekala, Richard W. (Pleasant Hill, CA)

    1991-01-01T23:59:59.000Z

    The polycondensation of resorcinol with formaldehyde under alkaline conditions results in the formation of surface functionalized polymer "Clusters". The covalent crosslinking of these "clusters" produces gels which when processed under supercritical conditions, produce low density, organic aerogels (density.ltoreq.100 mg/cc; cell size .ltoreq.0.1 microns). The aerogels are transparent, dark red in color and consist of interconnected colloidal-like particles with diameters of about 100.circle.. These aerogels may be further carbonized to form low density carbon foams with cell size of about 0.1 micron.

  9. Kinetic Theory for Binary Granular Mixtures at Low-Density

    E-Print Network [OSTI]

    Vicente Garzo

    2007-04-10T23:59:59.000Z

    Many features of granular media can be modelled as a fluid of hard spheres with {\\em inelastic} collisions. Under rapid flow conditions, the macroscopic behavior of grains can be described through hydrodynamic equations. At low-density, a fundamental basis for the derivation of the hydrodynamic equations and explicit expressions for the transport coefficients appearing in them is provided by the Boltzmann kinetic theory conveniently modified to account for inelastic binary collisions. The goal of this chapter is to give an overview of the recent advances made for binary granular gases by using kinetic theory tools. Some of the results presented here cover aspects such as transport properties, energy nonequipartition, instabilities, segregation or mixing, non-Newtonian behavior, .... In addition, comparison of the analytical results with those obtained from Monte Carlo and molecular dynamics simulations is also carried out, showing the reliability of kinetic theory to describe granular flows even for strong dissipation.

  10. GyPSuM: A Detailed Tomographic Model of Mantle Density and Seismic Wave Speeds

    SciTech Connect (OSTI)

    Simmons, N A; Forte, A M; Boschi, L; Grand, S P

    2010-03-30T23:59:59.000Z

    GyPSuM is a tomographic model fo mantle seismic shear wave (S) speeds, compressional wave (P) speeds and detailed density anomalies that drive mantle flow. the model is developed through simultaneous inversion of seismic body wave travel times (P and S) and geodynamic observations while considering realistic mineral physics parameters linking the relative behavior of mantle properties (wave speeds and density). Geodynamic observations include the (up to degree 16) global free-air gravity field, divergence of the tectonic plates, dynamic topography of the free surface, and the flow-induced excess ellipticity of the core-mantle boundary. GyPSuM is built with the philosophy that heterogeneity that most closely resembles thermal variations is the simplest possible solution. Models of the density field from Earth's free oscillations have provided great insight into the density configuration of the mantle; but are limited to very long-wavelength solutions. Alternatively, simply scaling higher resolution seismic images to density anomalies generates density fields that do not satisfy geodynamic observations. The current study provides detailed density structures in the mantle while directly satisfying geodynamic observations through a joint seismic-geodynamic inversion process. Notable density field observations include high-density piles at the base of the superplume structures, supporting the fundamental results of past normal mode studies. However, these features are more localized and lower amplitude than past studies would suggest. When we consider all seismic anomalies in GyPSuM, we find that P and S-wave speeds are strongly correlated throughout the mantle. However, correlations between the high-velocity S zones in the deep mantle ({approx} 2000 km depth) and corresponding P-wave anomalies are very low suggesting a systematic divergence from simplified thermal effects in ancient subducted slab anomalies. Nevertheless, they argue that temperature variations are the primary cause of P-wave, S-wave, and density anomalies in the mantle.

  11. Hyperbolic Dynamics Todd Fisher

    E-Print Network [OSTI]

    Fisher, Todd

    Hyperbolic Dynamics Todd Fisher tfisher@math.umd.edu Department of Mathematics University of Maryland, College Park Hyperbolic Dynamics ­ p. 1/3 #12;What is a dynamical system? Phase space X, elements possible states Hyperbolic Dynamics ­ p. 2/3 #12;What is a dynamical system? Phase space X, elements

  12. Alpha track density using a semiconductor detector

    E-Print Network [OSTI]

    Hamilton, Ian Scott

    1993-01-01T23:59:59.000Z

    of factors including variation in the initial dielectric thickness, and other undefined parameters. In addition, the resultant radon concentration reading is dependent upon the calibration factor used to interpret the track density reading. Obtaining...

  13. Breast Density and Cancer | GE Global Research

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

    Breast Cancer Awareness Series: Understanding Breast Density Click to email this to a friend (Opens in new window) Share on Facebook (Opens in new window) Click to share (Opens in...

  14. Magnetic fields and density functional theory

    SciTech Connect (OSTI)

    Salsbury Jr., Freddie

    1999-02-01T23:59:59.000Z

    A major focus of this dissertation is the development of functionals for the magnetic susceptibility and the chemical shielding within the context of magnetic field density functional theory (BDFT). These functionals depend on the electron density in the absence of the field, which is unlike any other treatment of these responses. There have been several advances made within this theory. The first of which is the development of local density functionals for chemical shieldings and magnetic susceptibilities. There are the first such functionals ever proposed. These parameters have been studied by constructing functionals for the current density and then using the Biot-Savart equations to obtain the responses. In order to examine the advantages and disadvantages of the local functionals, they were tested numerically on some small molecules.

  15. Density controlled carbon nanotube array electrodes

    DOE Patents [OSTI]

    Ren, Zhifeng F. (Newton, MA); Tu, Yi (Belmont, MA)

    2008-12-16T23:59:59.000Z

    CNT materials comprising aligned carbon nanotubes (CNTs) with pre-determined site densities, catalyst substrate materials for obtaining them and methods for forming aligned CNTs with controllable densities on such catalyst substrate materials are described. The fabrication of films comprising site-density controlled vertically aligned CNT arrays of the invention with variable field emission characteristics, whereby the field emission properties of the films are controlled by independently varying the length of CNTs in the aligned array within the film or by independently varying inter-tubule spacing of the CNTs within the array (site density) are disclosed. The fabrication of microelectrode arrays (MEAs) formed utilizing the carbon nanotube material of the invention is also described.

  16. Inverse diffusion from knowledge of power densities

    E-Print Network [OSTI]

    Bal, Guillaume; Monard, Francois; Triki, Faouzi

    2011-01-01T23:59:59.000Z

    This paper concerns the reconstruction of a diffusion coefficient in an elliptic equation from knowledge of several power densities. The power density is the product of the diffusion coefficient with the square of the modulus of the gradient of the elliptic solution. The derivation of such internal functionals comes from perturbing the medium of interest by acoustic (plane) waves, which results in small changes in the diffusion coefficient. After appropriate asymptotic expansions and (Fourier) transformation, this allow us to construct the power density of the equation point-wise inside the domain. Such a setting finds applications in ultrasound modulated electrical impedance tomography and ultrasound modulated optical tomography. We show that the diffusion coefficient can be uniquely and stably reconstructed from knowledge of a sufficient large number of power densities. Explicit expressions for the reconstruction of the diffusion coefficient are also provided. Such results hold for a large class of boundary...

  17. High density load bearing insulation peg

    DOE Patents [OSTI]

    Nowobilski, J.J.; Owens, W.J.

    1985-01-29T23:59:59.000Z

    A high density peg is disclosed which can support a large load and exhibits excellent thermal resistance produced by a method wherein the peg is made in compliance with specified conditions of time, temperature and pressure. 4 figs.

  18. Tweedie Family Densities: Methods of Evaluation

    E-Print Network [OSTI]

    Smyth, Gordon K.

    of Queensland, St Lucia, Q 4072, Australia. 2 University of Southern Queensland, Toowoomba, Q 4350, Australia. Tweedie family densities are characterised by power variance functions of the form V[µ] = µp , where p

  19. Shock compression of low-density foams

    SciTech Connect (OSTI)

    Holmes, N.C.

    1993-07-01T23:59:59.000Z

    Shock compression of very low density micro-cellular materials allows entirely new regimes of hot fluid states to be investigated experimentally. Using a two-stage light-gas gun to generate strong shocks, temperatures of several eV are readily achieved at densities of roughly 0.5--1 g/cm{sup 3} in large, uniform volumes. The conditions in these hot, expanded fluids are readily found using the Hugoniot jump conditions. We will briefly describe the basic methodology for sample preparation and experimental measurement of shock velocities. We present data for several materials over a range of initial densities. This paper will explore the applications of these methods for investigations of equations of state and phase diagrams, spectroscopy, and plasma physics. Finally, we discus the need for future work on these and related low-density materials.

  20. Microscopic Description of Nuclear Fission Dynamics

    E-Print Network [OSTI]

    A. S. Umar; V. E. Oberacker; J. A. Maruhn; P. -G. Reinhard

    2010-03-22T23:59:59.000Z

    We discuss possible avenues to study fission dynamics starting from a time-dependent mean-field approach. Previous attempts to study fission dynamics using the time-dependent Hartree-Fock (TDHF) theory are analyzed. We argue that different initial conditions may be needed to describe fission dynamics depending on the specifics of the fission phenomenon and propose various approaches towards this goal. In particular, we provide preliminary calculations for studying fission following a heavy-ion reaction using TDHF with a density contraint. Regarding prompt muon-induced fission, we also suggest a new approach for combining the time-evolution of the muonic wave function with a microscopic treatment of fission dynamics via TDHF.

  1. QCD Level Density from Maximum Entropy Method

    E-Print Network [OSTI]

    Shinji Ejiri; Tetsuo Hatsuda

    2005-09-24T23:59:59.000Z

    We propose a method to calculate the QCD level density directly from the thermodynamic quantities obtained by lattice QCD simulations with the use of the maximum entropy method (MEM). Understanding QCD thermodynamics from QCD spectral properties has its own importance. Also it has a close connection to phenomenological analyses of the lattice data as well as experimental data on the basis of hadronic resonances. Our feasibility study shows that the MEM can provide a useful tool to study QCD level density.

  2. Density Profiles of Liquid/Vapor Interfaces Away from Their Critical Point

    E-Print Network [OSTI]

    Wei Bu; Doseok Kim; David Vaknin

    2014-04-28T23:59:59.000Z

    We examine the applicability of various model profiles for the liquid/vapor interface by X-ray reflectivities on water and ethanol and their mixtures at room temperature. Analysis of the X-ray reflecivities using various density profiles shows an error-function like profile is the most adequate within experimental error. Our finding, together with recent observations from simulation studies on liquid surfaces, strongly suggest that the capillary-wave dynamics shapes the interfacial density profile in terms of the error function.

  3. Empirical vertical structure of density anomaly in the Gulf of Mexico

    E-Print Network [OSTI]

    Current, Carole Louise

    1993-01-01T23:59:59.000Z

    ) or Arango and Reid (1990b). Following custom in dealing with the dynamics of ocean circulation, we will treat the velocity (V) field as being nondivergent, (V V) = 0. The conservation of potential density is represented by the relation 1Dp ? =0 pDt (2... entering as a dependent variable, 8 84 +V? VB& =0 (2. 1. 4) and momentum equations, oV ? +V V?V+fkxV+V?b= F ot and given that ( is the upwardly positive rest state elevation of a potential density surface. Thus g is a function of p, and N (the Brunt...

  4. Density Profiles of Liquid/Vapor Interfaces Away from Their Critical Points

    SciTech Connect (OSTI)

    Bu, Wei; Kim, Doseok; Vaknin, David

    2014-06-12T23:59:59.000Z

    We examine the applicability of various model profiles for the liquid/vapor interface by X-ray reflectivities on water and ethanol and their mixtures at room temperature. Analysis of the X-ray reflecivities using various density profiles shows an error-function like profile is the most adequate within experimental error. Our findings, together with recent observations from simulation studies on liquid surfaces, strongly suggest that the capillary-wave dynamics shapes the interfacial density profile in terms of the error function.

  5. Ligand identification using electron-density mapcorrelations

    SciTech Connect (OSTI)

    Terwilliger, Thomas C.; Adams, Paul D.; Moriarty, Nigel W.; Cohn,Judith D.

    2006-12-01T23:59:59.000Z

    A procedure for the identification of ligands bound incrystal structuresof macromolecules is described. Two characteristics ofthe density corresponding to a ligand are used in the identificationprocedure. One is the correlation of the ligand density with each of aset of test ligands after optimization of the fit of that ligand to thedensity. The other is the correlation of a fingerprint of the densitywith the fingerprint of model density for each possible ligand. Thefingerprints consist of an ordered list of correlations of each the testligands with the density. The two characteristics are scored using aZ-score approach in which the correlations are normalized to the mean andstandard deviation of correlations found for a variety of mismatchedligand-density pairs, so that the Z scores are related to the probabilityof observing a particular value of the correlation by chance. Theprocedure was tested with a set of 200 of the most commonly found ligandsin the Protein Data Bank, collectively representing 57 percent of allligands in the Protein Data Bank. Using a combination of these twocharacteristics of ligand density, ranked lists of ligand identificationswere made for representative (F-o-F-c) exp(i phi(c)) difference densityfrom entries in the Protein Data Bank. In 48 percent of the 200 cases,the correct ligand was at the top of the ranked list of ligands. Thisapproach may be useful in identification of unknown ligands in newmacromolecular structures as well as in the identification of whichligands in a mixture have bound to a macromolecule.

  6. The Microscopic Linear Dynamics

    E-Print Network [OSTI]

    Penny, Will

    The Microscopic Brain Will Penny Linear Dynamics Exponentials Matrix Exponential Eigendecomposition Dynamical Modes Nodes State Space Saddles Oscillations Spirals Centres Offsets Retinal Circuit Nullclines Stability Spiking Neurons Fitzhugh-Nagumo Nonlinear Dynamics Linearization Nonlinear Oscillation Excitable

  7. STANDING WAVE PROBES FOR DIMENSIONAL METROLOGY OF LOW DENSITY FOAMS

    SciTech Connect (OSTI)

    Seugling, R M; Woody, S C; Bauza, M B

    2010-03-23T23:59:59.000Z

    Typically, parts and geometries of interest to LLNL are made from a combination of complex geometries and a wide array of different materials ranging from metals and ceramics to low density foams and plastic foils. These parts are combined to develop physics experiments for studying material properties, equation of state (EOS) and radiation transport. Understanding the dimensional uncertainty of the parts contained within an experiment is critical to the physical understanding of the phenomena being observed and represents the motivation for developing probe metrology capability that can address LLNL's unique problems. Standing wave probes were developed for measuring high aspect ratio, micrometer scaled features with nanometer resolution. Originally conceived of for the use in the automotive industry for characterizing fuel injector bores and similar geometries, this concept was investigated and improved for use on geometries and materials important to LLNL needs within target fabrication. As part of the original project, detailed understanding of the probe dynamics and interactions with the surface of the sample was investigated. In addition, the upgraded system was utilized for measuring fuel injector bores and micro-lenses as a means of demonstrating capability. This report discusses the use of the standing wave probe for measuring features in low density foams, 55 mg/cc SiO{sub 2} and 982 mg/cc (%6 relative density) copper foam respectively. These two foam materials represent a difficult metrology challenge because of their material properties and surface topography. Traditional non-contact metrology systems such as normal incident interferometry and/or confocal microscopy have difficulty obtaining a signal from the relatively absorptive characteristics of these materials. In addition to the foam samples, a solid copper and plastic (Rexolite{trademark}) sample of similar geometry was measured with the standing wave probe as a reference for both conductive and dielectric materials.

  8. First Results of the LHC Longitudinal Density Monitor

    SciTech Connect (OSTI)

    Jeff, A.; /CERN /Liverpool U.; Boccardi, A.; /CERN; Bravin, E.; /CERN; Fisher, A.S.; /SLAC; Lefevre, T.; /CERN; Rabiller, A.; /CERN; Roncarolo, F.; /CERN; Welsch, C.P.; /Liverpool U. /Cockcroft Inst. Accel. Sci. Tech.

    2012-04-19T23:59:59.000Z

    The Large Hadron Collider (LHC) at CERN is the world's largest particle accelerator. It is designed to accelerate and collide protons or heavy ions up to the center-of-mass energies of 14 TeV. Knowledge of the longitudinal distribution of particles is important for various aspects of accelerator operation, in particular to check the injection quality and to measure the proportion of charge outside the nominally filled bunches during the physics periods. In order to study this so-called ghost charge at levels very much smaller than the main bunches, a longitudinal profile measurement with a very high dynamic range is needed. A new detector, the LHC Longitudinal Density Monitor (LDM) is a single-photon counting system measuring synchrotron light by means of an avalanche photodiode detector. The unprecedented energies reached in the LHC allow synchrotron light diagnostics to be used with both protons and heavy ions. A prototype was installed during the 2010 LHC run and was able to longitudinally profile the whole ring with a resolution close to the target of 50 ps. On-line correction for the effects of the detector deadtime, pile-up and afterpulsing allow a dynamic range of 105 to be achieved. First measurements with the LDM are presented here along with an analysis of its performance and an outlook for future upgrades.

  9. Reduced density matrix hybrid approach: Application to electronic energy transfer

    SciTech Connect (OSTI)

    Berkelbach, Timothy C.; Reichman, David R. [Department of Chemistry, Columbia University, 3000 Broadway, New York, New York 10027 (United States); Markland, Thomas E. [Department of Chemistry, Stanford University, 333 Campus Drive, Stanford, California 94305 (United States)

    2012-02-28T23:59:59.000Z

    Electronic energy transfer in the condensed phase, such as that occurring in photosynthetic complexes, frequently occurs in regimes where the energy scales of the system and environment are similar. This situation provides a challenge to theoretical investigation since most approaches are accurate only when a certain energetic parameter is small compared to others in the problem. Here we show that in these difficult regimes, the Ehrenfest approach provides a good starting point for a dynamical description of the energy transfer process due to its ability to accurately treat coupling to slow environmental modes. To further improve on the accuracy of the Ehrenfest approach, we use our reduced density matrix hybrid framework to treat the faster environmental modes quantum mechanically, at the level of a perturbative master equation. This combined approach is shown to provide an efficient and quantitative description of electronic energy transfer in a model dimer and the Fenna-Matthews-Olson complex and is used to investigate the effect of environmental preparation on the resulting dynamics.

  10. Reduced density matrix hybrid approach: Application to electronic energy transfer

    E-Print Network [OSTI]

    Timothy C. Berkelbach; Thomas E. Markland; David R. Reichman

    2011-11-21T23:59:59.000Z

    Electronic energy transfer in the condensed phase, such as that occurring in photosynthetic complexes, frequently occurs in regimes where the energy scales of the system and environment are similar. This situation provides a challenge to theoretical investigation since most approaches are accurate only when a certain energetic parameter is small compared to others in the problem. Here we show that in these difficult regimes, the Ehrenfest approach provides a good starting point for a dynamical description of the energy transfer process due to its ability to accurately treat coupling to slow environmental modes. To further improve on the accuracy of the Ehrenfest approach, we use our reduced density matrix hybrid framework to treat the faster environmental modes quantum mechanically, at the level of a perturbative master equation. This combined approach is shown to provide an efficient and quantitative description of electronic energy transfer in a model dimer and the Fenna-Matthews-Olson complex and is used to investigate the effect of environmental preparation on the resulting dynamics.

  11. PHASE SEPARATION IN InGaN/GaN MULTIPLE QUANTUM WELLS M.D. MCCLUSKEY *, L.T. ROMANO *, B.S. KRUSOR *, D.P. BOUR *, C. CHUA *, N.M.

    E-Print Network [OSTI]

    McCluskey, Matthew

    985 PHASE SEPARATION IN InGaN/GaN MULTIPLE QUANTUM WELLS M.D. MCCLUSKEY *, L.T. ROMANO *, B0.27Ga0.73N/GaN multiple quantum wells (MQW's). After annealing for 4 min at a temperature of 1100 o is attributed to the formation of In- rich InGaN phases in the active region. X-ray diffraction measurements

  12. DISORDERING OF InGaN/GaN SUPERLATTICES AFTER HIGH-PRESSURE M.D. McCluskey*, L.T. Romano**, B.S. Krusor**, D. Hofstetter**, D.P. Bour**, M. Kneissl**,

    E-Print Network [OSTI]

    McCluskey, Matthew

    DISORDERING OF InGaN/GaN SUPERLATTICES AFTER HIGH-PRESSURE ANNEALING M.D. McCluskey*, L.T. Romano Internet J. Nitride Semicond. Res. 4S1, G3.42 (1999) ABSTRACT Interdiffusion of In and Ga is observed in InGaN of up to 15 kbar were applied during the annealing treatments to prevent decomposition of the InGaN

  13. Dynamics of colloidal particles in ice

    E-Print Network [OSTI]

    Melissa Spannuth; S. G. J. Mochrie; S. S. L. Peppin; J. S. Wettlaufer

    2010-12-31T23:59:59.000Z

    We use X-ray Photon Correlation Spectroscopy (XPCS) to probe the dynamics of colloidal particles in polycrystalline ice. During freezing, the dendritic ice morphology and rejection of particles from the ice created regions of high-particle-density, where some of the colloids were forced into contact and formed disordered aggregates. We find that the particles in these high density regions underwent ballistic motion coupled with both stretched and compressed exponential decays of the intensity autocorrelation function, and that the particles' characteristic velocity increased with temperature. We explain this behavior in terms of ice grain boundary migration.

  14. Causes and consequences of complex population dynamics in an annual plant, Cardamine pensylvanica

    SciTech Connect (OSTI)

    Crone, E.E.

    1995-11-08T23:59:59.000Z

    The relative importance of density-dependent and density-independent factors in determining the population dynamics of plants has been widely debated with little resolution. In this thesis, the author explores the effects of density-dependent population regulation on population dynamics in Cardamine pensylvanica, an annual plant. In the first chapter, she shows that experimental populations of C. pensylvanica cycled from high to low density in controlled constant-environment conditions. These cycles could not be explained by external environmental changes or simple models of direct density dependence (N{sub t+1} = f[N{sub t}]), but they could be explained by delayed density dependence (N{sub t+1} = f[N{sub t}, N{sub t+1}]). In the second chapter, she shows that the difference in the stability properties of population growth models with and without delayed density dependence is due to the presence of Hopf as well as slip bifurcations from stable to chaotic population dynamics. She also measures delayed density dependence due to effects of parental density on offspring quality in C. pensylvanica and shows that this is large enough to be the cause of the population dynamics observed in C. pensylvanica. In the third chapter, the author extends her analyses of density-dependent population growth models to include interactions between competing species. In the final chapter, she compares the effects of fixed spatial environmental variation and variation in population size on the evolutionary response of C. pensylvanica populations.

  15. Nuclear energy density optimization: Shell structure

    E-Print Network [OSTI]

    M. Kortelainen; J. McDonnell; W. Nazarewicz; E. Olsen; P. -G. Reinhard; J. Sarich; N. Schunck; S. M. Wild; D. Davesne; J. Erler; A. Pastore

    2014-04-28T23:59:59.000Z

    Nuclear density functional theory is the only microscopical theory that can be applied throughout the entire nuclear landscape. Its key ingredient is the energy density functional. In this work, we propose a new parameterization UNEDF2 of the Skyrme energy density functional. The functional optimization is carried out using the POUNDerS optimization algorithm within the framework of the Skyrme Hartree-Fock-Bogoliubov theory. Compared to the previous parameterization UNEDF1, restrictions on the tensor term of the energy density have been lifted, yielding a very general form of the energy density functional up to second order in derivatives of the one-body density matrix. In order to impose constraints on all the parameters of the functional, selected data on single-particle splittings in spherical doubly-magic nuclei have been included into the experimental dataset. The agreement with both bulk and spectroscopic nuclear properties achieved by the resulting UNEDF2 parameterization is comparable with UNEDF1. While there is a small improvement on single-particle spectra and binding energies of closed shell nuclei, the reproduction of fission barriers and fission isomer excitation energies has degraded. As compared to previous UNEDF parameterizations, the parameter confidence interval for UNEDF2 is narrower. In particular, our results overlap well with those obtained in previous systematic studies of the spin-orbit and tensor terms. UNEDF2 can be viewed as an all-around Skyrme EDF that performs reasonably well for both global nuclear properties and shell structure. However, after adding new data aiming to better constrain the nuclear functional, its quality has improved only marginally. These results suggest that the standard Skyrme energy density has reached its limits and significant changes to the form of the functional are needed.

  16. Protein Dynamics and Biocatalysis

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

    Protein Dynamics and Biocatalysis Protein Dynamics and Biocatalysis 1998 Annual Report Grand Challenge Projects biocatalysis.gif A model of the Michaelis complex for the TEM-1...

  17. Formation of droplets with high baryon density at the QCD phase transition in expanding matter

    E-Print Network [OSTI]

    Christoph Herold; Marlene Nahrgang; Igor Mishustin; Marcus Bleicher

    2014-07-22T23:59:59.000Z

    We consider the (3+1) dimensional expansion and cooling of the chirally-restored and deconfined matter at finite net-baryon densities as expected in heavy-ion collisions at moderate energies. In our approach, we consider chiral fields and the Polyakov loop as dynamical variables coupled to a medium represented by a quark-antiquark fluid. The interaction between the fields and the fluid leads to dissipation and noise, which in turn affect the field fluctuations. We demonstrate how inhomogeneities in the net-baryon density may form during an evolution through the spinodal region of the first-order phase transition. For comparison, the dynamics of transition through the crossover and critical end point is also considered.

  18. Probability density adjoint for sensitivity analysis of the Mean of Chaos

    SciTech Connect (OSTI)

    Blonigan, Patrick J., E-mail: blonigan@mit.edu; Wang, Qiqi, E-mail: qiqi@mit.edu

    2014-08-01T23:59:59.000Z

    Sensitivity analysis, especially adjoint based sensitivity analysis, is a powerful tool for engineering design which allows for the efficient computation of sensitivities with respect to many parameters. However, these methods break down when used to compute sensitivities of long-time averaged quantities in chaotic dynamical systems. This paper presents a new method for sensitivity analysis of ergodic chaotic dynamical systems, the density adjoint method. The method involves solving the governing equations for the system's invariant measure and its adjoint on the system's attractor manifold rather than in phase-space. This new approach is derived for and demonstrated on one-dimensional chaotic maps and the three-dimensional Lorenz system. It is found that the density adjoint computes very finely detailed adjoint distributions and accurate sensitivities, but suffers from large computational costs.

  19. Dynamics of Kr in dense clathrate hydrates.

    SciTech Connect (OSTI)

    Klug, D. D.; Tse, J. S.; Zhao, J. Y.; Sturhahn, W.; Alp, E. E.; Tulk, C. A. (X-Ray Science Division); (National Research Council of Canada); (Univ. of Saskatchewan); (ORNL)

    2011-01-01T23:59:59.000Z

    The dynamics of Kr atoms as guests in dense clathrate hydrate structures are investigated using site specific {sup 83}Kr nuclear resonant inelastic x-ray scattering (NRIXS) spectroscopy in combination with molecular dynamics simulations. The dense structure H hydrate and filled-ice structures are studied at high pressures in a diamond anvil high-pressure cell. The dynamics of Kr in the structure H clathrate hydrate quench recovered at 77 K is also investigated. The Kr phonon density of states obtained from the experimental NRIXS data are compared with molecular dynamics simulations. The temperature and pressure dependence of the phonon spectra provide details of the Kr dynamics in the clathrate hydrate cages. Comparison with the dynamics of Kr atoms in the low-pressure structure II obtained previously was made. The Lamb-Mossbauer factor obtained from NRIXS experiments and molecular dynamics calculations are in excellent agreement and are shown to yield unique information on the strength and temperature dependence of guest-host interactions.

  20. Tracing spiral density waves in M81

    E-Print Network [OSTI]

    S. Kendall; R. C. Kennicutt; C. Clarke; M. D. Thornley

    2008-04-15T23:59:59.000Z

    We use SPITZER IRAC 3.6 and 4.5micron near infrared data from the Spitzer Infrared Nearby Galaxies Survey (SINGS), optical B, V and I and 2MASS Ks band data to produce mass surface density maps of M81. The IRAC 3.6 and 4.5micron data, whilst dominated by emission from old stellar populations, is corrected for small-scale contamination by young stars and PAH emission. The I band data are used to produce a mass surface density map by a B-V colour-correction, following the method of Bell and de Jong. We fit a bulge and exponential disc to each mass map, and subtract these components to reveal the non-axisymmetric mass surface density. From the residual mass maps we are able to extract the amplitude and phase of the density wave, using azimuthal profiles. The response of the gas is observed via dust emission in the 8micron IRAC band, allowing a comparison between the phase of the stellar density wave and gas shock. The relationship between this angular offset and radius suggests that the spiral structure is reasonably long lived and allows the position of corotation to be determined.

  1. Laser control of free-carrier density in solids through field-enhanced multiphonon tunneling recombination

    SciTech Connect (OSTI)

    Zheltikov, A. M.; Voronin, A. A. [Department of Physics, International Laser Center, M.V. Lomonosov Moscow State University, Moscow 119992 (Russian Federation); Shneider, M. N.; Miles, R. B. [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544-5263 (United States)

    2011-02-01T23:59:59.000Z

    Enhancement of multiphonon tunneling recombination of free carriers in strong laser fields is shown to offer a mechanism whereby ultrafast carrier-density dynamics in a semiconductor can be controlled by properly shaped laser pulses. This regime of laser-solid interaction enables an ultrafast switching of optical and electric properties of semiconductor materials, suggesting new strategies for laser micromachining and nanomachining, optical data processing, and ultrafast plasmonics.

  2. High power density solid oxide fuel cells

    SciTech Connect (OSTI)

    Pham, Ai Quoc; Glass, Robert S.

    2004-10-12T23:59:59.000Z

    A method for producing ultra-high power density solid oxide fuel cells (SOFCs). The method involves the formation of a multilayer structure cells wherein a buffer layer of doped-ceria is deposited intermediate a zirconia electrolyte and a cobalt iron based electrode using a colloidal spray deposition (CSD) technique. For example, a cobalt iron based cathode composed of (La,Sr)(Co,Fe)O (LSCF) may be deposited on a zirconia electrolyte via a buffer layer of doped-ceria deposited by the CSD technique. The thus formed SOFC have a power density of 1400 mW/cm.sup.2 at 600.degree. C. and 900 mW/cm.sup.2 at 700.degree. C. which constitutes a 2-3 times increased in power density over conventionally produced SOFCs.

  3. Statistical approach to nuclear level density

    SciTech Connect (OSTI)

    Sen'kov, R. A.; Horoi, M. [Department of Physics, Central Michigan University, Mount Pleasant, MI 48859 (United States); Zelevinsky, V. G. [Department of Physics and Astronomy and National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824-1321 (United States)

    2014-10-15T23:59:59.000Z

    We discuss the level density in a finite many-body system with strong interaction between the constituents. Our primary object of applications is the atomic nucleus but the same techniques can be applied to other mesoscopic systems. We calculate and compare nuclear level densities for given quantum numbers obtained by different methods, such as nuclear shell model (the most successful microscopic approach), our main instrument - moments method (statistical approach), and Fermi-gas model; the calculation with the moments method can use any shell-model Hamiltonian excluding the spurious states of the center-of-mass motion. Our goal is to investigate statistical properties of nuclear level density, define its phenomenological parameters, and offer an affordable and reliable way of calculation.

  4. Fabrication of low density ceramic material

    DOE Patents [OSTI]

    Meek, T.T.; Blake, R.D.; Sheinberg, H.

    1985-01-01T23:59:59.000Z

    A precursor mixture and a method of making a low-density ceramic structural material are disclosed. The precursor mixture includes hollow microballoons, typically made of glass, together with a cementing agent capable of being cured by microwave irradiation. A preferred cementing agent is liquid hydrated potassium silicate, which is mixed with the glass microballoons to form a slurry. Upon irradiation the potassium silicate is dehydrated to form a solid porous matrix in which the microballoons are evenly distributed. Ground glass or other filling agents may be included in the slurry to enhance the properties of the final product. Low-density structural ceramics having densities on the order of 0.1 to 0.3 are obtained.

  5. Precise and Accurate Density Determination of Explosives Using Hydrostatic Weighing

    SciTech Connect (OSTI)

    B. Olinger

    2005-07-01T23:59:59.000Z

    Precise and accurate density determination requires weight measurements in air and water using sufficiently precise analytical balances, knowledge of the densities of air and water, knowledge of thermal expansions, availability of a density standard, and a method to estimate the time to achieve thermal equilibrium with water. Density distributions in pressed explosives are inferred from the densities of elements from a central slice.

  6. Density matrix of black hole radiation

    E-Print Network [OSTI]

    Lasma Alberte; Ram Brustein; Andrei Khmelnitsky; A. J. M. Medved

    2015-02-09T23:59:59.000Z

    Hawking's model of black hole evaporation is not unitary and leads to a mixed density matrix for the emitted radiation, while the Page model describes a unitary evaporation process in which the density matrix evolves from an almost thermal state to a pure state. We compare a recently proposed model of semiclassical black hole evaporation to the two established models. In particular, we study the density matrix of the outgoing radiation and determine how the magnitude of the off-diagonal corrections differs for the three frameworks. For Hawking's model, we find power-law corrections to the two-point functions that induce exponentially suppressed corrections to the off-diagonal elements of the full density matrix. This verifies that the Hawking result is correct to all orders in perturbation theory and also allows one to express the full density matrix in terms of the single-particle density matrix. We then consider the semiclassical theory for which the corrections, being non-perturbative from an effective field-theory perspective, are much less suppressed and grow monotonically in time. In this case, the R\\'enyi entropy for the outgoing radiation is shown to grow linearly at early times; but this growth slows down and the entropy eventually starts to decrease at the Page time. In addition to comparing models, we emphasize the distinction between the state of the radiation emitted from a black hole, which is highly quantum, and that of the radiation emitted from a typical classical black body at the same temperature.

  7. Error Analysis in Nuclear Density Functional Theory

    E-Print Network [OSTI]

    Nicolas Schunck; Jordan D. McDonnell; Jason Sarich; Stefan M. Wild; Dave Higdon

    2014-07-11T23:59:59.000Z

    Nuclear density functional theory (DFT) is the only microscopic, global approach to the structure of atomic nuclei. It is used in numerous applications, from determining the limits of stability to gaining a deep understanding of the formation of elements in the universe or the mechanisms that power stars and reactors. The predictive power of the theory depends on the amount of physics embedded in the energy density functional as well as on efficient ways to determine a small number of free parameters and solve the DFT equations. In this article, we discuss the various sources of uncertainties and errors encountered in DFT and possible methods to quantify these uncertainties in a rigorous manner.

  8. Low density, microcellular foams, preparation, and articles

    DOE Patents [OSTI]

    Young, A.T.

    1982-03-03T23:59:59.000Z

    A microcellular low-density foam of poly(4-methyl-1-pentene) particularly useful for forming targets for inertial confinement fusion has been developed. Articles made from the foam have been machined to tolerances of 0.0001 inch, although the densities of the fragile foam are low (about 10 to about 100 mg/cc) and the cell sizes are small (about 10 to about 30 ..mu..m). Methods for forming the foam and articles are given. The yield strength of the foam of the invention is higher than was obtained in other structures of this same material.

  9. Low density, microcellular foams, preparation, and articles

    DOE Patents [OSTI]

    Young, Ainslie T. (Los Alamos, NM); Marsters, Robert G. (Jemez Springs, NM); Moreno, Dawn K. (Espanola, NM)

    1984-01-01T23:59:59.000Z

    A microcellular low density foam of poly(4-methyl-1-pentene) which is particularly useful for forming targets for inertial confinement fusion has been developed. Articles made from the foam have been machined to tolerances of 0.0001 inch, although the densities of the fragile foam are low (about 10 to about 100 mg/cc) and the cell sizes are small (about 10 to about 30 .mu.m). Methods for forming the foam and articles are given; and the yield strength of the foam of the invention is higher than was obtained in other structures of this same material.

  10. Configuration Interactions Constrained by Energy Density Functionals

    E-Print Network [OSTI]

    B. Alex Brown; Angelo Signoracci; Morten Hjorth-Jensen

    2010-09-24T23:59:59.000Z

    A new method for constructing a Hamiltonian for configuration interaction calculations with constraints to energies of spherical configurations obtained with energy-density-functional (EDF) methods is presented. This results in a unified model that reproduced the EDF binding-energy in the limit of single-Slater determinants, but can also be used for obtaining energy spectra and correlation energies with renormalized nucleon-nucleon interactions. The three-body and/or density-dependent terms that are necessary for good nuclear saturation properties are contained in the EDF. Applications to binding energies and spectra of nuclei in the region above 208Pb are given.

  11. Level densities of transitional Sm nuclei

    SciTech Connect (OSTI)

    Capote, R.; Ventura, A.; Cannata, F.; Quesada, J.M. [Nuclear Data Section, International Atomic Energy Agency, Vienna (Austria); Ente Nuove Tecnologie, Energia e Ambiente, and Istituto Nazionale di Fisica Nucleare, Bologna (Italy); Dipartimento di Fisica dell Universita and Istituto Nazionale di Fisica Nucleare, Bologna (Italy); Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Sevilla (Spain)

    2005-06-01T23:59:59.000Z

    Experimentally determined level densities of the transitional isotopes {sup 148,149,150,152}Sm at excitation energies below and around the neutron binding energy are compared with microcanonical calculations based on a Monte Carlo approach to noncollective level densities, folded with a collective enhancement estimated in the frame of the interacting boson model (IBM). The IBM parameters are adjusted so as to reproduce the low-lying discrete levels of both parities, with the exception of the odd-mass nucleus, {sup 149}Sm, where complete decoupling of the unpaired neutron from the core is assumed.

  12. Dynamics of Motivations

    E-Print Network [OSTI]

    Knoll, Jörn

    Dynamics of Resonances GSI, 18.05.2005 Motivations Thermal Equilibrium -N- vectormesons Di-leptons Towards dynamics Conserving -functional Gradient ap- proximation Quantum Kinetic Equation Summary Dynamics. Voskresensky1,3 1GSI 2Kurchatov Inst. (Moscow) 3Moscow Ins. for Physics and Engineering #12;Dynamics

  13. Dynamics on Lorentz manifolds

    E-Print Network [OSTI]

    Zeghib, Abdelghani

    Dynamics on Lorentz manifolds Abdelghani Zeghib Introduction Motivations and questions Examples Results Results Previous results Linear Dynamics General considerations Furstenberg Lemma Lorentz Dynamics://www.umpa.ens-lyon.fr/~zeghib/ (joint work with Paolo Piccione) #12;Dynamics on Lorentz manifolds Abdelghani Zeghib Introduction

  14. Introduction Basic dynamics

    E-Print Network [OSTI]

    LaCasce, Joseph H.

    Introduction Basic dynamics The Gulf Stream The thermohaline circulation Ocean currents: some misconceptions and some dynamics Joe LaCasce Dept. Geosciences October 30, 2012 Joe LaCasce Dept. Geosciences Ocean currents: some misconceptions and some dynamics #12;Introduction Basic dynamics The Gulf Stream

  15. Stochastic thermodynamics of fluctuating density fields: Non-equilibrium free energy differences under coarse-graining

    SciTech Connect (OSTI)

    Leonard, T.; Lander, B.; Seifert, U. [II. Institut für Theoretische Physik, Universität Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart (Germany)] [II. Institut für Theoretische Physik, Universität Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart (Germany); Speck, T. [Institut für Theoretische Physik II, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf (Germany)] [Institut für Theoretische Physik II, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf (Germany)

    2013-11-28T23:59:59.000Z

    We discuss the stochastic thermodynamics of systems that are described by a time-dependent density field, for example, simple liquids and colloidal suspensions. For a time-dependent change of external parameters, we show that the Jarzynski relation connecting work with the change of free energy holds if the time evolution of the density follows the Kawasaki-Dean equation. Specifically, we study the work distributions for the compression and expansion of a two-dimensional colloidal model suspension implementing a practical coarse-graining scheme of the microscopic particle positions. We demonstrate that even if coarse-grained dynamics and density functional do not match, the fluctuation relations for the work still hold albeit for a different, apparent, change of free energy.

  16. Maps of current density using density-functional methods A. Soncini,1,a

    E-Print Network [OSTI]

    Helgaker, Trygve

    , University of Durham, South Road, Durham DH1 3LE, United Kingdom Received 22 May 2008; accepted 17 July 2008 are compared and integration of the current densities to yield shielding constants is performed. In general of induced current density in molecules. © 2008 American Institute of Physics. DOI: 10.1063/1.2969104 I

  17. On the Determination of the Mean Cosmic Matter Density and the Amplitude of Density Fluctuations

    E-Print Network [OSTI]

    Thomas H. Reiprich

    2002-07-02T23:59:59.000Z

    The cosmological implications from a new estimate of the local X-ray galaxy cluster abundance are summarized. The results are then compared to independent observations. It is suggested that `low' values for the mean cosmic matter density and the amplitude of mass density fluctuations currently do not appear unreasonable observationally.

  18. Dynamics of the Upper Oceanic Layers in Terms of Surface Quasigeostrophy Theory G. LAPEYRE AND P. KLEIN

    E-Print Network [OSTI]

    Lapeyre, Guillaume

    Dynamics of the Upper Oceanic Layers in Terms of Surface Quasigeostrophy Theory G. LAPEYRE AND P dynamics for nonlinear baroclinically unstable flows is examined using the concepts of potential vorticity density anomalies. Then, using the invertibility of potential vorticity, the dynamics are decomposed

  19. PHYSICAL REVIEW A 87, 053406 (2013) Exterior complex scaling method in time-dependent density-functional theory

    E-Print Network [OSTI]

    Chu, Shih-I

    2013-01-01T23:59:59.000Z

    -correlation potential which proved accurate in calculations of unperturbed electronic structure of Ar. Calculations is, not including dynamic response of the electron density) differ significantly from those obtained [2­4]. Electronic structure of atoms and molecules can be encoded in the HHG signal; the latter may

  20. Density of vacuum energy for multidimensional model of Kazner with scalar field and cosmological birth of particles

    E-Print Network [OSTI]

    Sergey Yakovlev

    2011-12-22T23:59:59.000Z

    In the work's considered density of vacuum energy and dynamic of scalar field in multidimensional theory with cosmological constant. Using method of N.N.Bogolubov coefficients, was gotten expression for influence of anisotropic metric to vacuum energy. Obtained the effective mass of massles scalar field, that depends on cosmological constant, and some general theoretical results concerning arising of particles in the model.

  1. 2810 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 39, NO. 11, NOVEMBER 2011 The Effect of Critical Plasma Densities of

    E-Print Network [OSTI]

    Harilal, S. S.

    -produced plasma (LPP) for various applications should consider details of spatial and temporal input power de in hydro- dynamic evolution of the produced plasma sources. Index Terms--CO2 laser, critical density and optimization of radiation sources for the next generation of nanolithography, i.e., the extreme ultravi- olet

  2. High power density supercapacitors using locally aligned carbon nanotube electrodes

    E-Print Network [OSTI]

    Du, C S; Yeh, J; Pan, Ning

    2005-01-01T23:59:59.000Z

    4484/16/4/003 High power density supercapacitors usingproduced very high speci?c power density of about 30 kW kg ?manufacturing of high power density supercapacitors and

  3. High-power-density spot cooling using bulk thermoelectrics

    E-Print Network [OSTI]

    Zhang, Y; Shakouri, A; Zeng, G H

    2004-01-01T23:59:59.000Z

    model, the cooling power densities of the devices can alsothe cooling power densities 2–24 times. Experimentally, the14 4 OCTOBER 2004 High-power-density spot cooling using bulk

  4. Mechanical constraints enhance electrical energy densities of soft dielectrics

    E-Print Network [OSTI]

    Ferrari, Silvia

    Mechanical constraints enhance electrical energy densities of soft dielectrics Lin Zhang, Qiming, the dielectric will breakdown electrically. The breakdown limits the electrical energy density of the dielectric electric fields and thus increase their electrical energy densities. The mechanical constraints suppress

  5. Density waves in the Calogero model - revisited

    SciTech Connect (OSTI)

    Bardek, V. [Rudjer Boskovic Institute, Bijenicka c.54, HR-10002 Zagreb (Croatia)], E-mail: bardek@irb.hr; Feinberg, J. [Department of Physics, University of Haifa at Oranim, Tivon 36006 (Israel); Department of Physics, Technion-Israel Inst. of Technology, Haifa 32000 (Israel); KITP, University of California, Santa Barbara, CA 93106-4030 (United States)], E-mail: joshua@physics.technion.ac.il; Meljanac, S. [Rudjer Boskovic Institute, Bijenicka c.54, HR-10002 Zagreb (Croatia)], E-mail: meljanac@irb.hr

    2010-03-15T23:59:59.000Z

    The Calogero model bears, in the continuum limit, collective excitations in the form of density waves and solitary modulations of the density of particles. This sector of the spectrum of the model was investigated, mostly within the framework of collective-field theory, by several authors, over the past 15 years or so. In this work we shall concentrate on periodic solutions of the collective BPS-equation (also known as 'finite amplitude density waves'), as well as on periodic solutions of the full static variational equations which vanish periodically (also known as 'large amplitude density waves'). While these solutions are not new, we feel that our analysis and presentation add to the existing literature, as we explain in the text. In addition, we show that these solutions also occur in a certain two-family generalization of the Calogero model, at special points in parameter space. A compendium of useful identities associated with Hilbert transforms, including our own proofs of these identities, appears in Appendix A. In Appendix B we also elucidate in the present paper some fine points having to do with manipulating Hilbert-transforms, which appear ubiquitously in the collective field formalism. Finally, in order to make this paper self-contained, we briefly summarize in Appendix C basic facts about the collective field formulation of the Calogero model.

  6. Density-Functional Theory for Complex Fluids

    E-Print Network [OSTI]

    Wu, Jianzhong

    . This generic methodology is built upon a mathematical theorem that states, for an equilibrium system at a given modeling of the microscopic struc- tures and phase behavior of soft-condensed matter. The methodol- ogy to the one-body density profile Grand potential: the free energy of an open system at fixed volume

  7. Photovoltaic retinal prosthesis with high pixel density

    E-Print Network [OSTI]

    Palanker, Daniel

    Photovoltaic retinal prosthesis with high pixel density Keith Mathieson1,4 , James Loudin1 to stimulating electrodes via intraocular cables. We present a photovoltaic subretinal prosthesis, in which pixel, demonstrating the possibility of a fully integrated photovoltaic retinal prosthesis with high

  8. Methods to enhance blanket power density

    SciTech Connect (OSTI)

    Hsu, P.Y.; Miller, L.G.; Bohn, T.S.; Deis, G.A.; Longhurst, G.R.; Masson, L.S.; Wessol, D.E.; Abdou, M.A.

    1982-06-01T23:59:59.000Z

    The overall objective of this task is to investigate the extent to which the power density in the FED/INTOR breeder blanket test modules can be enhanced by artificial means. Assuming a viable approach can be developed, it will allow advanced reactor blanket modules to be tested on FED/INTOR under representative conditions.

  9. Durable high-density data storage

    SciTech Connect (OSTI)

    Stutz, R.A.; Lamartine, B.C.

    1996-09-01T23:59:59.000Z

    This paper will discuss the Focus Ion Beam (FIB) milling process, media life considerations, and methods of reading the micromilled data. The FIB process for data storage provides a new non-magnetic storage method for archiving large amounts of data. The process stores data on robust materials such as steel, silicon, and gold coated silicon. The storage process was developed to provide a method to insure the long term storage life of data. We estimate the useful life of data written on silicon or gold coated silicon to be a few thousand years. The process uses an ion beam to carve material from the surface much like stone cutting. The deeper information is carved into the media the longer the expected life of the information. The process can read information in three formats: (1) binary at densities of 3.5 Gbits/cm{sup 2}, (2) alphanumeric at optical or non-optical density, and (3) graphical at optical and non-optical density. The formats can be mixed on the same media; and thus it is possible to record, in a human readable format, instructions that can be read using an optical microscope. These instructions provide guidance on reading the higher density information.

  10. Density Functional Theory Models for Radiation Damage

    E-Print Network [OSTI]

    Density Functional Theory Models for Radiation Damage S.L. Dudarev EURATOM/CCFE Fusion Association and informative as the most advanced experimental techniques developed for the observation of radiation damage investigation and assessment of radiation damage effects, offering new insight into the origin of temperature

  11. High power density thermophotovoltaic energy conversion

    SciTech Connect (OSTI)

    Noreen, D.L. [R& D Technologies, Inc., Hoboken, New Jersey 07030 (United States); Du, H. [Department of Materials Science and Engineering, Stevens Institute of Technology, Hoboken, New Jersey 07030 (United States)

    1995-01-05T23:59:59.000Z

    R&D Technologies is developing thermophotovoltaic (TPV) technology based on the use of porous/fibrous ceramic broadband-type emitter designs that utilize recuperative or regenerative techniques to improve thermal efficiency and power density. This paper describes preliminary estimates of what will be required to accomplish sufficient power density to develop a practical, commercially-viable TPV generator. It addresses the needs for improved, thermal shock-resistant, long-life porous/fibrous ceramic emitters and provides information on the photocell technology required to achieve acceptable power density in broadband-type (with selective filter) TPV systems. TPV combustors/systems operating at a temperature of 1500 {degree}C with a broadband-type emitter is proposed as a viable starting point for cost-effective TPV conversion. Based on current projections for photocell cost, system power densities of 7.5--10 watts per square centimeter of emitter area will be required for TPV to become a commercially viable technology. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  12. Estimating density of Florida Key deer

    E-Print Network [OSTI]

    Roberts, Clay Walton

    2006-08-16T23:59:59.000Z

    for this species since 1968; however, a need to evaluate the precision of existing and alternative survey methods (i.e., road counts, mark-recapture, infrared-triggered cameras [ITC]) was desired by USFWS. I evaluated density estimates from unbaited ITCs and road...

  13. Population density of San Joaquin kit fox

    SciTech Connect (OSTI)

    McCue, P.; O'Farrell, T.P.; Kato, T.; Evans, B.G.

    1982-01-01T23:59:59.000Z

    Populations of the endangered San Joaquin kit fox, vulpes macrotis mutica, are known to occur on the Elk Hills Naval Petroleum Reserve No. 1. This study assess the impact of intensified petroleum exploration and production and associated human activities on kit fox population density. (ACR)

  14. Effective Field Theory and Finite Density Systems

    E-Print Network [OSTI]

    R. J. Furnstahl; G. Rupak; T. Schaefer

    2008-01-04T23:59:59.000Z

    This review gives an overview of effective field theory (EFT) as applied at finite density, with a focus on nuclear many-body systems. Uniform systems with short-range interactions illustrate the ingredients and virtues of many-body EFT and then the varied frontiers of EFT for finite nuclei and nuclear matter are surveyed.

  15. Molecular Dynamics Simulations of Uranyl and Uranyl Carbonate Adsorption at Alumino-silicate Surfaces

    SciTech Connect (OSTI)

    Kerisit, Sebastien N.; Liu, Chongxuan

    2014-03-03T23:59:59.000Z

    Adsorption at mineral surfaces is a critical factor controlling the mobility of uranium(VI) in aqueous environments. Therefore, molecular dynamics (MD) simulations were performed to investigate uranyl(VI) adsorption onto two neutral alumino-silicate surfaces, namely the orthoclase (001) surface and the octahedral aluminum sheet of the kaolinite (001) surface. Although uranyl preferentially adsorbed as a bi-dentate innersphere complex on both surfaces, the free energy of adsorption at the orthoclase surface (-15 kcal mol-1) was significantly more favorable than that at the kaolinite surface (-3 kcal mol-1), which was attributed to differences in surface functional groups and to the ability of the orthoclase surface to dissolve a surface potassium ion upon uranyl adsorption. The structures of the adsorbed complexes compared favorably with X-ray absorption spectroscopy results. Simulations of the adsorption of uranyl complexes with up to three carbonate ligands revealed that uranyl complexes coordinated to up to 2 carbonate ions are stable on the orthoclase surface whereas uranyl carbonate surface complexes are unfavored at the kaolinite surface. Combining the MD-derived equilibrium adsorption constants for orthoclase with aqueous equilibrium constants for uranyl carbonate species indicates the presence of adsorbed uranium complexes with one or two carbonates in alkaline conditions, in support of current uranium(VI) surface complexation models.

  16. Interfacial Ionic Liquids: Connecting Static and Dynamic Structures

    E-Print Network [OSTI]

    Ahmet Uysal; Hua Zhou; Guang Feng; Sang Soo Lee; Song Li; Peter T. Cummings; Pasquale F. Fulvio; Sheng Dai; John K. McDonough; Yury Gogotsi; Paul Fenter

    2014-12-06T23:59:59.000Z

    It is well-known that room temperature ionic liquids (RTILs) often adopt a charge-separated layered structure, i.e., with alternating cation- and anion-rich layers, at electrified interfaces. However, the dynamic response of the layered structure to temporal variations in applied potential is not well understood. We used in situ, real-time X-ray reflectivity (XR) to study the potential-dependent electric double layer (EDL) structure of an imidazolium-based RTIL on charged epitaxial graphene during potential cycling as a function of temperature. The results suggest that the graphene-RTIL interfacial structure is bistable in which the EDL structure at any intermediate potential can be described by the combination of two extreme-potential structures whose proportions vary depending on the polarity and magnitude of the applied potential. This picture is supported by the EDL structures obtained by fully atomistic molecular dynamics (MD) simulations at various static potentials. The potential-driven transition between the two structures is characterized by an increasing width but with an approximately fixed hysteresis magnitude as a function of temperature. The results are consistent with the coexistence of distinct anion and cation adsorbed structures separated by an energy barrier (~0.15 eV).

  17. Stochastic dynamics of collective modes for Brownian dipoles

    E-Print Network [OSTI]

    Leticia F. Cugliandolo; Pierre-Michel Déjardin; Gustavo S. Lozano; Frédéric van Wijland

    2014-12-19T23:59:59.000Z

    The individual motion of a colloidal particle is described by an overdamped Langevin equation. When rotational degrees of freedom are relevant, these are described by a corresponding Langevin process. Our purpose is to show that the microscopic local density of colloids, in terms of a space and rotation state, also evolves according to a Langevin equation. The latter can then be used as the starting point of a variety of approaches, ranging from dynamical density functional theory to mode-coupling approximations.

  18. ?Linear Gas Jet with Tailored Density Profile"

    SciTech Connect (OSTI)

    KRISHNAN, Mahadevan

    2012-12-10T23:59:59.000Z

    Supersonic, highly collimated gas jets and gas-filled capillary discharge waveguides are two primary targets of choice for Laser Plasma Accelerators (LPA) . Present gas jets have lengths of only 2-4 mm at densities of 1-4E19 cm-3, sufficient for self trapping and electron acceleration to energies up to ~150 MeV. Capillary structures 3 cm long have been used to accelerate beams up to 1 GeV. Capillary discharges used in LPAs serve to guide the pump laser and optimize the energy gain. A wall-stabilized capillary discharge provides a transverse profile across the channel that helps guide the laser and combat diffraction. Gas injection via a fast nozzle at one end provides some longitudinal density control, to improve the coupling. Gas jets with uniform or controlled density profiles may be used to control electron bunch injection and are being integrated into capillary experiments to add tuning of density. The gas jet for electron injection has not yet been optimized. Our Ph-I results have provided the LPA community with an alternative path to realizing a 2-3GeV electron bunch using just a gas jet. For example, our slit/blade combination gives a 15-20mm long acceleration path with tunable density profile, serving as an alternative to a 20-mm long capillary discharge with gas injection at one end. In Ph-II, we will extend these results to longer nozzles, to see whether we can synthesize 30 or 40-mm long plasma channels for LPAs.

  19. Molecular Dynamics Simulation of the Transport Properties of Molten Transuranic Chloride Salts

    E-Print Network [OSTI]

    Baty, Austin Alan

    2013-02-06T23:59:59.000Z

    are critical to modeling both the neutronics and heat transfer of an ADSMS system. There is a lack of experimental data on the density, heat capacity, electrical and thermal conductivities, and viscosity of TRUCl3 salt systems. Molecular dynamics simulations...

  20. Dynamic First-Principles Molecular-Scale Model for Solid Oxide Fuel Cells V. Hugo Schmidt

    E-Print Network [OSTI]

    Dynamic First-Principles Molecular-Scale Model for Solid Oxide Fuel Cells V. Hugo Schmidt vs. current density i characteristics applies both to the Solid Oxide Fuel Cell (SOFC) and Solid

  1. E-Cloud Effects on Singe-Bunch Dynamics in the Proposed PS2

    E-Print Network [OSTI]

    Venturini, M.

    2012-01-01T23:59:59.000Z

    E-CLOUD EFFECTS ON SINGLE-BUNCH DYNAMICS IN THE PROPOSEDsynchrotron. Electron cloud effects represent an impor- tantaiming at estimating the e-cloud density thresholds for the

  2. Theoretical Electron Density Distributions for Fe- and Cu-Sulfide...

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

    Electron Density Distributions for Fe- and Cu-Sulfide Earth Materials: A Connection between Bond Length, Bond Theoretical Electron Density Distributions for Fe- and Cu-Sulfide...

  3. A Density Functional Theory Study of Formaldehyde Adsorption...

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

    Density Functional Theory Study of Formaldehyde Adsorption on Ceria. A Density Functional Theory Study of Formaldehyde Adsorption on Ceria. Abstract: Molecular adsorption of...

  4. Effects of van der Waals Density Functional Corrections on Trends...

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

    van der Waals Density Functional Corrections on Trends in Furfural Adsorption and Hydrogenation on Close-Packed Effects of van der Waals Density Functional Corrections on Trends in...

  5. Pauling bond strength, bond length and electron density distribution...

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

    Pauling bond strength, bond length and electron density distribution. Pauling bond strength, bond length and electron density distribution. Abstract: A power law regression...

  6. TEMPO-based Catholyte for High Energy Density Nonaqueous Redox...

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

    TEMPO-based Catholyte for High Energy Density Nonaqueous Redox Flow Batteries. TEMPO-based Catholyte for High Energy Density Nonaqueous Redox Flow Batteries. Abstract: We will...

  7. Using Radio Waves to Control Fusion Plasma Density

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

    Using Radio Waves to Control Fusion Plasma Density Using Radio Waves to Control Fusion Plasma Density Simulations Run at NERSC Support Fusion Experiments at MIT, General Atomics...

  8. High Energy Density Laboratory Plasmas Program | National Nuclear...

    National Nuclear Security Administration (NNSA)

    Photo Gallery Jobs Apply for Our Jobs Our Jobs Working at NNSA Blog Home High Energy Density Laboratory Plasmas Program High Energy Density Laboratory Plasmas Program...

  9. High power density supercapacitors using locally aligned carbon nanotube electrodes

    E-Print Network [OSTI]

    Du, C S; Yeh, J; Pan, Ning

    2005-01-01T23:59:59.000Z

    High power density supercapacitors using locally alignedof high power density supercapacitors and other similarcells [6], and for supercapacitors [7–18]. As unique energy

  10. Effects of Ambient Density and Temperature on Soot Formation...

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

    Density and Temperature on Soot Formation under High-EGR Conditions Effects of Ambient Density and Temperature on Soot Formation under High-EGR Conditions Presentation given at...

  11. Mitigating Breakdown in High Energy Density Perovskite Polymer...

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

    Mitigating Breakdown in High Energy Density Perovskite Polymer Nanocomposite Capacitors Mitigating Breakdown in High Energy Density Perovskite Polymer Nanocomposite Capacitors 2012...

  12. Density Functional Theory Study of Oxygen Reduction Activity...

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

    Density Functional Theory Study of Oxygen Reduction Activity on Ultrathin Platinum Nanotubes. Density Functional Theory Study of Oxygen Reduction Activity on Ultrathin Platinum...

  13. A new Lagrangian dynamic reduction in field theory

    E-Print Network [OSTI]

    François Gay-Balmaz; Tudor S. Ratiu

    2014-07-01T23:59:59.000Z

    For symmetric classical field theories on principal bundles there are two methods of symmetry reduction: covariant and dynamic. Assume that the classical field theory is given by a symmetric covariant Lagrangian density defined on the first jet bundle of a principal bundle. It is shown that covariant and dynamic reduction lead to equivalent equations of motion. This is achieved by constructing a new Lagrangian defined on an infinite dimensional space which turns out to be gauge group invariant.

  14. Lower crustal density estimation using the density-slowness relationship: a preliminary study

    E-Print Network [OSTI]

    Jones, Gary Wayne

    1996-01-01T23:59:59.000Z

    , and seismic velocity models were used to estimate the densities of th lower crustal rocks frcm the Wind River Mountains, the Ivrea Zone in Italy, and the average 1~ continental crustal model developed b/ ~istensen and Mconey [1995] . The. densities... by Carlson and Raskin [1984) yields a precision of about 1 percent. 'Ihe objective of this study is to evaluate this approach to estimate the density of the more complex continental crust, which is more variable in composition and affected hy a wider range...

  15. Structural fluctuations and quantum transport through DNA molecular wires: a combined molecular dynamics and model Hamiltonian approach

    E-Print Network [OSTI]

    R. Gutierrez; R. Caetano; P. B. Woiczikowski; T. Kubar; M. Elstner; G. Cuniberti

    2009-10-02T23:59:59.000Z

    Charge transport through a short DNA oligomer (Dickerson dodecamer) in presence of structural fluctuations is investigated using a hybrid computational methodology based on a combination of quantum mechanical electronic structure calculations and classical molecular dynamics simulations with a model Hamiltonian approach. Based on a fragment orbital description, the DNA electronic structure can be coarse-grained in a very efficient way. The influence of dynamical fluctuations arising either from the solvent fluctuations or from base-pair vibrational modes can be taken into account in a straightforward way through time series of the effective DNA electronic parameters, evaluated at snapshots along the MD trajectory. We show that charge transport can be promoted through the coupling to solvent fluctuations, which gate the onsite energies along the DNA wire.

  16. Current density fluctuations and ambipolarity of transport

    SciTech Connect (OSTI)

    Shen, W.; Dexter, R.N.; Prager, S.C.

    1991-10-01T23:59:59.000Z

    The fluctuation in the plasma current density is measured in the MIST reversed field pinch experiment. Such fluctuations, and the measured radial profile of the k spectrum of magnetic fluctuations, supports the view and that low frequency fluctuations (f < 30 kHz) are tearing modes and high frequency fluctuations (30 kHz < f < 250 kHz) are localized turbulence in resonance with the local equilibrium magnetic field (i.e., k {center dot} B = 0). Correlation of current density and magnetic fluctuations (< {tilde j}{parallel}{tilde B}{sub r} >) demonstrates that radial particle transport from particle motion parallel to a fluctuating magnetic field is ambipolar over the full frequency range.

  17. Current density fluctuations and ambipolarity of transport

    SciTech Connect (OSTI)

    Shen, W.; Dexter, R.N.; Prager, S.C.

    1991-10-01T23:59:59.000Z

    The fluctuation in the plasma current density is measured in the MIST reversed field pinch experiment. Such fluctuations, and the measured radial profile of the k spectrum of magnetic fluctuations, supports the view and that low frequency fluctuations (f < 30 kHz) are tearing modes and high frequency fluctuations (30 kHz < f < 250 kHz) are localized turbulence in resonance with the local equilibrium magnetic field (i.e., k {center_dot} B = 0). Correlation of current density and magnetic fluctuations (< {tilde j}{parallel}{tilde B}{sub r} >) demonstrates that radial particle transport from particle motion parallel to a fluctuating magnetic field is ambipolar over the full frequency range.

  18. Oblique interactions of dust density waves

    SciTech Connect (OSTI)

    Wang, Zhelchui [Los Alamos National Laboratory; Li, Yang - Fang [MAX-PLANCK INSTITUTE; Hou, Lujing [MAX-PLANCK INSTITUTE; Jiang, Ke [MAX-PLANCK INSTITUTE; Wu, De - Jin [CHINA; Thomas, Hubertus M [MAX-PLANCK INSTITUTE; Morfill, Gregor E [MAX-PLANCK INSTITUTE

    2010-01-01T23:59:59.000Z

    Self-excited dust density waves (DDWs) are studied in a striped electrode device. In addition to the usual perpendicularly (with respect to the electrode) propagating DDWs, which have been frequently observed in dusty plasma experiments on the ground, a low-frequency oblique mode is also observed. This low-frequency oblique DDW has a frequency much lower than the dust plasma frequency and its spontaneous excitation is observed even with a very low dust density. It is found that the low-frequency oblique mode can exist either separately or together with the usual perpendicular mode. In the latter case, a new mode arises as a result of the interactions between the perpendicular and the oblique modes. The experiments show that these three modes satisfy the wave coupling conditions in both the frequencies and the wave-vectors.

  19. Global coherence of dust density waves

    SciTech Connect (OSTI)

    Killer, Carsten; Melzer, André [Institut für Physik, Ernst-Moritz-Arndt-Universität Greifswald, 17489 Greifswald (Germany)

    2014-06-15T23:59:59.000Z

    The coherence of self-excited three-dimensional dust density waves has been experimentally investigated by comparing global and local wave properties. For that purpose, three-dimensional dust clouds have been confined in a radio frequency plasma with thermophoretic levitation. Global wave properties have been measured from the line-of-sight integrated dust density obtained from homogenous light extinction measurements. Local wave properties have been obtained from thin, two-dimensional illuminated laser slices of the cloud. By correlating the simultaneous global and local wave properties, the spatial coherence of the waves has been determined. We find that linear waves with small amplitudes tend to be fragmented, featuring an incoherent wave field. Strongly non-linear waves with large amplitudes, however, feature a strong spatial coherence throughout the dust cloud, indicating a high level of synchronization.

  20. Ultra-high density diffraction grating

    DOE Patents [OSTI]

    Padmore, Howard A.; Voronov, Dmytro L.; Cambie, Rossana; Yashchuk, Valeriy V.; Gullikson, Eric M.

    2012-12-11T23:59:59.000Z

    A diffraction grating structure having ultra-high density of grooves comprises an echellette substrate having periodically repeating recessed features, and a multi-layer stack of materials disposed on the echellette substrate. The surface of the diffraction grating is planarized, such that layers of the multi-layer stack form a plurality of lines disposed on the planarized surface of the structure in a periodical fashion, wherein lines having a first property alternate with lines having a dissimilar property on the surface of the substrate. For example, in one embodiment, lines comprising high-Z and low-Z materials alternate on the planarized surface providing a structure that is suitable as a diffraction grating for EUV and soft X-rays. In some embodiments, line density of between about 10,000 lines/mm to about 100,000 lines/mm is provided.

  1. Development of Silica Aerogel with Any Density

    E-Print Network [OSTI]

    M. Tabata; I. Adachi; T. Fukushima; H. Kawai; H. Kishimoto; A. Kuratani; H. Nakayama; S. Nishida; T. Noguchi; K. Okudaira; Y. Tajima; H. Yano; H. Yokogawa; H. Yoshida

    Abstract–New production methods of silica aerogel with high and low refractive indices have been developed. A very slow shrinkage of alcogel at room temperature has made possible producing aerogel with high refractive indices of up to 1.265 without cracks. Even higher refractive indices than 1.08, the transmission length of the aerogel obtained from this technique has been measured to be about 10 to 20 mm at 400 nm wave length. A mold made of alcogel which endures shrinkage in the supercritical drying process has provided aerogel with the extremely low density of 0.009g/cm 3, which corresponds to the refractive index of 1.002. We have succeeded producing aerogel with a wide range of densities. I.

  2. Density equalizing map projections: A new algorithm

    SciTech Connect (OSTI)

    Merrill, D.W.; Selvin, S.; Mohr, M.S.

    1992-02-01T23:59:59.000Z

    In the study of geographic disease clusters, an alternative to traditional methods based on rates is to analyze case locations on a transformed map in which population density is everywhere equal. Although the analyst`s task is thereby simplified, the specification of the density equalizing map projection (DEMP) itself is not simple and continues to be the subject of considerable research. Here a new DEMP algorithm is described, which avoids some of the difficulties of earlier approaches. The new algorithm (a) avoids illegal overlapping of transformed polygons; (b) finds the unique solution that minimizes map distortion; (c) provides constant magnification over each map polygon; (d) defines a continuous transformation over the entire map domain; (e) defines an inverse transformation; (f) can accept optional constraints such as fixed boundaries; and (g) can use commercially supported minimization software. Work is continuing to improve computing efficiency and improve the algorithm.

  3. Density equalizing map projections: A new algorithm

    SciTech Connect (OSTI)

    Merrill, D.W.; Selvin, S.; Mohr, M.S.

    1992-02-01T23:59:59.000Z

    In the study of geographic disease clusters, an alternative to traditional methods based on rates is to analyze case locations on a transformed map in which population density is everywhere equal. Although the analyst's task is thereby simplified, the specification of the density equalizing map projection (DEMP) itself is not simple and continues to be the subject of considerable research. Here a new DEMP algorithm is described, which avoids some of the difficulties of earlier approaches. The new algorithm (a) avoids illegal overlapping of transformed polygons; (b) finds the unique solution that minimizes map distortion; (c) provides constant magnification over each map polygon; (d) defines a continuous transformation over the entire map domain; (e) defines an inverse transformation; (f) can accept optional constraints such as fixed boundaries; and (g) can use commercially supported minimization software. Work is continuing to improve computing efficiency and improve the algorithm.

  4. Nuclear fission in covariant density functional theory

    E-Print Network [OSTI]

    A. V. Afanasjev; H. Abusara; P. Ring

    2013-09-12T23:59:59.000Z

    The current status of the application of covariant density functional theory to microscopic description of nuclear fission with main emphasis on superheavy nuclei (SHN) is reviewed. The softness of SHN in the triaxial plane leads to an emergence of several competing fission pathes in the region of the inner fission barrier in some of these nuclei. The outer fission barriers of SHN are considerably affected both by triaxiality and octupole deformation.

  5. Energy-momentum Density of Gravitational Waves

    E-Print Network [OSTI]

    Amir M. Abbassi; Saeed Mirshekari

    2014-11-29T23:59:59.000Z

    In this paper, we elaborate the problem of energy-momentum in general relativity by energy-momentum prescriptions theory. Our aim is to calculate energy and momentum densities for the general form of gravitational waves. In this connection, we have extended the previous works by using the prescriptions of Bergmann and Tolman. It is shown that they are finite and reasonable. In addition, using Tolman prescription, exactly, leads to same results that have been obtained by Einstein and Papapetrou prescriptions.

  6. Update of axion CDM energy density

    SciTech Connect (OSTI)

    Huh, Ji-Haeng [Department of Physics and Astronomy and Center for Theoretical Physics, Seoul National University, Seoul 151-747 (Korea, Republic of)

    2008-11-23T23:59:59.000Z

    We update cosmological bound on axion model. The contribution from the anharmonic effect and the newly introduced initial overshoot correction are considered. We present an explicit formula for the axion relic density in terms of the QCD scale {lambda}{sub QCD}, the current quark masses m{sub q}'s and the Peccei-Quinn scale F{sub a}, including firstly introduced 1.85 factor which is from the initial overshoot.

  7. Fiber felts as low density structural materials

    SciTech Connect (OSTI)

    Milewski, J.V.; Newfield, S.E.

    1981-01-01T23:59:59.000Z

    Short fiber felts structures can be made which provide improvements in properties over foams. In applications where resistance to compression set or stress relaxation are important, bonded fiber felts excel due to the flexing of individual fibers within their elastic limit. Felts of stainless steel and polyester fibers were prepared by deposition from liquid slurries. Compressive properties were determined as a function of felt parent material, extent of bonding, felt density, and length-to-diameter (L/D) ratio of starting fibers.

  8. Spatially resolved dynamic structure factor of finite systems from molecular dynamics simulations

    SciTech Connect (OSTI)

    Raitza, Thomas; Roepke, Gerd; Reinholz, Heidi; Morozov, Igor [Institut fuer Physik, Universitaet Rostock, D-18051 Rostock (Germany); Institut fuer Theoretische Physik, Johannes-Kepler-Universitaet Linz, A-4040 Linz, Austria and Institute of Physics, University of Western Australia, Perth, WA 6009 (Australia); Joint Institute for High Temperatures of RAS, 13 Izhorskaya Street, Building 2, Moscow RU-125412 (Russian Federation)

    2011-09-15T23:59:59.000Z

    The dynamical response of metallic clusters up to 10{sup 3} atoms is investigated using the restricted molecular dynamics simulations scheme. Exemplarily, a sodium like material is considered. Correlation functions are evaluated to investigate the spatial structure of collective electron excitations and the optical response of laser-excited clusters. In particular, the spectrum of bilocal correlation functions shows resonances representing different modes of collective excitations inside the nano plasma. The spatial structure, the resonance energy, and the width of the eigenmodes have been investigated for various values of electron density, temperature, cluster size, and ionization degree. Comparison with bulk properties is performed and the dispersion relation of collective excitations is discussed.

  9. Propagation of a cloud of hot electrons through a plasma in the presence of Langmuir scattering by ambient density fluctuations

    SciTech Connect (OSTI)

    Foroutan, G. R.; Robinson, P. A.; Sobhanian, S.; Moslehi-Fard, M.; Li, B.; Cairns, I. H. [School of Physics, University of Sydney, NSW 2006, Sydney (Australia); Research Institute for Astronomy and Astrophysics of Maragha, P.O. Box 55134-441 Maragha (Iran, Islamic Republic of) and Physics Department, Faculty of Science, Sahand University of Technology, 51335-1996 Tabriz (Iran); School of Physics, University of Sydney, NSW 2006, Sydney (Australia); Research Institute for Astronomy and Astrophysics of Maragha, P.O. Box 55134-441 Maragha (Iran, Islamic Republic of) and Faculty of Physics, Tabriz University, Tabriz 51664 (Iran); Faculty of Physics, Tabriz University, Tabriz 51664 (Iran, Islamic Republic of); School of Physics, University of Sydney, NSW 2006, Sydney (Australia)

    2007-01-15T23:59:59.000Z

    Gas-dynamic theory is generalized to incorporate the effects of beam-driven Langmuir waves scattering off ambient density fluctuations, and the consequent effects on the propagation of a cloud of hot electrons in an inhomogeneous plasma. Assuming Langmuir scattering as the limit of nonlinear three-wave interactions with fluctuations that are weak, low-frequency, long-wavelength ion-sound waves, the net effect of scattering is equivalent to effective damping of the Langmuir waves. Under the assumption of self-similarity in the evolution of the beam and Langmuir wave distribution functions, gas-dynamic theory shows that the effects of Langmuir scattering on the beam distribution are equivalent to a perturbation in the injection profile of the beam. Analytical expressions are obtained for the height of the plateau of the beam distribution function, wave spectral number density, total wave and particle energy density, and the beam number density. The main results of gas-dynamic theory are then compared with simulation results from numerical solutions of quasilinear equations. The relaxation of the beam in velocity space is retarded in the presence of density fluctuations and the magnitude of the upper velocity boundary is less than that in the absence of fluctuations. There are four different regimes for the height of the plateau, corresponding to different stages of relaxation of the beam in velocity space. Moreover, Langmuir scattering results in transfer of electrons from moderate velocity to low velocity; this effect produces an enhancement in the beam number density at small distances near the injection site and a corresponding decrease at large distances. There are sharp decreases in the profiles of the beam and total wave energy densities, which are related to dissipation of energy at large phase velocities. Due to a slower velocity space diffusion of the beam distribution in the presence of scattering effects, the spatial width of the beam is reduced while its mean velocity of propagation increases slightly.

  10. Optimally focused cold atom systems obtained using density-density correlations

    SciTech Connect (OSTI)

    Putra, Andika; Campbell, Daniel L.; Price, Ryan M.; Spielman, I. B. [Joint Quantum Institute, University of Maryland and National Institute of Standards and Technology, College Park, Maryland 20742 (United States)] [Joint Quantum Institute, University of Maryland and National Institute of Standards and Technology, College Park, Maryland 20742 (United States); De, Subhadeep [Joint Quantum Institute, University of Maryland and National Institute of Standards and Technology, College Park, Maryland 20742 (United States) [Joint Quantum Institute, University of Maryland and National Institute of Standards and Technology, College Park, Maryland 20742 (United States); CSIR-National Physical Laboratory, New Delhi 110012 (India)

    2014-01-15T23:59:59.000Z

    Resonant absorption imaging is a common technique for detecting the two-dimensional column density of ultracold atom systems. In many cases, the system's thickness along the imaging direction greatly exceeds the imaging system's depth of field, making the identification of the optimally focused configuration difficult. Here we describe a systematic technique for bringing Bose-Einstein condensates (BEC) and other cold-atom systems into an optimal focus even when the ratio of the thickness to the depth of field is large: a factor of 8 in this demonstration with a BEC. This technique relies on defocus-induced artifacts in the Fourier-transformed density-density correlation function (the power spectral density, PSD). The spatial frequency at which these artifacts first appear in the PSD is maximized on focus; the focusing process therefore both identifies and maximizes the range of spatial frequencies over which the PSD is uncontaminated by finite-thickness effects.

  11. Tariffs with Dynamic Supply Response

    E-Print Network [OSTI]

    Karp, Larry

    1985-01-01T23:59:59.000Z

    Giannini FDN iibrary TARIFFS WITH DYNAMIC SUPPLY RESWNSEpaper studies the optimal tariff in a dynamic framework. Thesellers, the optimal tariff is dynam- ically inconsistent;

  12. Mode-dependent phonon transport analysis of silicon crystal by molecular dynamics method Takuma HORI*4

    E-Print Network [OSTI]

    Maruyama, Shigeo

    Mode Projection(NMP)(17,18,20,21) Spectral Energy Density (SED)(22) LDeMDu u'MDu' 1 Fig. 1 Flow chart[(8)] 22 0 )( 1 )( f (8) k(22) Fig. 3 Flow chart of the lattice dynamics method. 1 2 3 4 5 6 7 8 9 methods using normal mode projection and spectral energy density. By performing the calculations

  13. Dynamics of structural priming 

    E-Print Network [OSTI]

    Malhotra, Gaurav

    2009-01-01T23:59:59.000Z

    for understanding various aspects of syntactic priming. Cognitive processes are modelled as dynamical systems that can change their behaviour when they process information. We use these dynamical systems to investigate how each episode of language comprehension...

  14. Dynamical Friction on extended perturbers

    E-Print Network [OSTI]

    O. Esquivel; B. Fuchs

    2008-04-01T23:59:59.000Z

    Following a wave-mechanical treatment we calculate the drag force exerted by an infinite homogeneous background of stars on a perturber as this makes its way through the system. We recover Chandrasekhar's classical dynamical friction (DF) law with a modified Coulomb logarithm. We take into account a range of models that encompasses all plausible density distributions for satellite galaxies by considering the DF exerted on a Plummer sphere and a perturber having a Hernquist profile. It is shown that the shape of the perturber affects only the exact form of the Coulomb logarithm. The latter converges on small scales, because encounters of the test and field stars with impact parameters less than the size of the massive perturber become inefficient. We confirm this way earlier results based on the impulse approximation of small angle scatterings.

  15. Categorical Introduction to Dynamical Systems Symbolic Dynamical Systems

    E-Print Network [OSTI]

    Kahng, Byung-Jay

    Categorical Introduction to Dynamical Systems Symbolic Dynamical Systems Symbolic Embedding Examples Results Embeddings in Symbolic Dynamical Systems Jonathan Jaquette Swarthmore College July 22, 2009 Jonathan Jaquette Embeddings in Symbolic Dynamical Systems #12;Categorical Introduction

  16. Relaxation dynamics in a binary hard-ellipse liquid

    E-Print Network [OSTI]

    Wen-Sheng Xu; Zhao-Yan Sun; Li-Jia An

    2014-12-01T23:59:59.000Z

    Structural relaxation in binary hard spherical particles has been shown recently to exhibit a wealth of remarkable features when size disparity or mixture's composition is varied. In this paper, we test whether or not similar dynamical phenomena occur in glassy systems composed of binary hard ellipses. We demonstrate via event-driven molecular dynamics simulation that a binary hard-ellipse mixture with an aspect ratio of two and moderate size disparity displays characteristic glassy dynamics upon increasing density in both the translational and the rotational degrees of freedom. The rotational glass transition density is found to be close to the translational one for the binary mixtures investigated. More importantly, we assess the influence of size disparity and mixture's composition on the relaxation dynamics. We find that an increase of size disparity leads, both translationally and rotationally, to a speed up of the long-time dynamics in the supercooled regime so that both the translational and the rotational glass transition shift to higher densities. By increasing the number concentration of the small particles, the time evolution of both translational and rotational relaxation dynamics at high densities displays two qualitatively different scenarios, i.e., both the initial and the final part of the structural relaxation slow down for small size disparity, while the short-time dynamics still slows down but the final decay speeds up in the binary mixture with large size disparity. These findings are reminiscent of those observed in binary hard spherical particles. Therefore, our results suggest a universal mechanism for the influence of size disparity and mixture's composition on the structural relaxation in both isotropic and anisotropic particle systems.

  17. Dynamics of Carroll Particles

    E-Print Network [OSTI]

    Eric Bergshoeff; Joaquim Gomis; Giorgio Longhi

    2014-05-31T23:59:59.000Z

    We investigate particles whose dynamics is invariant under the Carroll group. Although a single free such Carroll particle has no non-trivial dynamics (`the Carroll particle does not move') we show that there exists non-trivial dynamics for a set of interacting Carroll particles. Furthermore, we gauge the Carroll algebra and couple the Carroll particle to these gauge fields. It turns out that for such a coupled system even a single Carroll particle can have non-trivial dynamics.

  18. Design for a Longitudinal Density Monitor for the LHC

    SciTech Connect (OSTI)

    Jeff, Adam; /CERN; Bart Pedersen, Stephane; /CERN; Boccardi, Andrea; /CERN; Bravin, Enrico; /CERN; Lefevre, Thibaut; /CERN; Rabiller, Aurelie; /CERN; Roncarolo, Federico; /CERN; Fisher, Alan; /SLAC; Welsch, Carsten; /Liverpool U.

    2012-07-13T23:59:59.000Z

    Synchrotron radiation is currently used on the LHC for beam imaging and for monitoring the proton population in the 3 microsecond abort gap. In addition to these existing detectors, a study has been initiated to provide longitudinal density profiles of the LHC beams with a high dynamic range and a 50ps time resolution. This would allow for the precise measurement both of the bunch shape and the number of particles in the bunch tail or drifting into ghost bunches. A solution is proposed based on counting synchrotron light photons with two fast avalanche photo-diodes (APD) operated in Geiger mode. One is free-running but heavily attenuated and can be used to measure the core of the bunch. The other is much more sensitive, for measurement of the bunch tails, but must be gated off during the passage of the bunch to prevent the detector from being swamped. An algorithm is then applied to combine the two measurements and correct for the detector dead-time, afterpulsing and pile-up effects. Initial results from laboratory testing of this system are described here.

  19. Design for a Longitudinal Density Monitor for the LHC

    E-Print Network [OSTI]

    Bart Pedersen, S; Boccardi, A; Fisher, AS; Jeff, A; Lefevre, T; Rabiller, A; Roncarolo, F; Welsch, CP

    2010-01-01T23:59:59.000Z

    Synchrotron radiation is currently used on the LHC for beam imaging and for monitoring the proton population in the 3 microsecond abort gap. In addition to these existing detectors, a study has been initiated to provide longitudinal density profiles of the LHC beams with a high dynamic range and a 50ps time resolution. This would allow for the precise measurement both of the bunch shape and the number of particles in the bunch tail or drifting into ghost bunches. A solution is proposed based on counting synchrotron light photons with two fast avalanche photo-diodes (APD) operated in Geiger mode. One is free-running but heavily attenuated and can be used to measure the core of the bunch. The other is much more sensitive, for measurement of the bunch tails, but must be gated off during the passage of the bunch to prevent the detector from being swamped. An algorithm is then applied to combine the two measurements and correct for the detector dead-time, after pulsing and pileup effects. Initial results from labo...

  20. First measurements results of the LHC longitudinal density monitor

    E-Print Network [OSTI]

    Jeff , A; Bravin, E; Boccardi, A; Bozyigit, S; Lefevre, T; Rabiller, A; Roncarolo, F; Welsch, C P; Fisher, A S

    2011-01-01T23:59:59.000Z

    Knowledge of the longitudinal distribution of particles is important for various aspects of accelerator operation, for example to check the injection quality and to characterize the development of ghost bunches before and during the physics periods. A new detector, the LHC Longitudinal Density Monitor (LDM) is a single-photon counting system measuring synchrotron light by means of an avalanche photodiode detector. The unprecedented energies reached in the LHC allow synchrotron light diagnostics to be used with both protons and heavy ions. The LDM is able to longitudinally profile the whole ring with a resolution close to the target of 50 ps. On-line correction for the effects of the detector deadtime, pile-up and afterpulsing allow a dynamic range of 105 to be achieved. The LDM operated during the 2010 lead ion run and during 2011 with protons. Measurements from both runs are presented in this contribution along with an analysis of the LDM performance and an outlook for future upgrades.

  1. Improvements of Fast Fluid Dynamics for Simulating Airflow in Mingang Jin1

    E-Print Network [OSTI]

    Chen, Qingyan "Yan"

    in buildings," Numerical Heat Transfer, Part B: Fundamentals, 62(6), 419-438. #12;2 density kinetic viscosity-765-494-0539 Abstract Fast Fluid Dynamics (FFD) could be potentially used for real-time indoor airflow simulations Dynamics (3D FFD).The implementation of boundary conditions at outlet was improved with local mass

  2. Computational Improvements to Quantum Wave Packet ab Initio Molecular Dynamics Using a Potential-Adapted,

    E-Print Network [OSTI]

    Iyengar, Srinivasan S.

    electronic structure calculations (at the level of density functional theory, Hartree-Fock, post- Hartree approach to treat the simultaneous dynamics of electrons and nuclei. The method is based on a synergy-H-Cl]- and [CH3-H-Cl]- along with simultaneous dynamical treatment of the electrons and classical nuclei, through

  3. Fast Valuation and Calibration of Credit Default Swaps Under Levy Dynamics

    E-Print Network [OSTI]

    Oosterlee, Cornelis W. "Kees"

    Fast Valuation and Calibration of Credit Default Swaps Under L´evy Dynamics Fang Fang , Henrik J. The method presented is based on the Fourier-cosine series expansion of the underlying model's density. Having a method to generate dynamic CDS spreads available, it is also possible to value so called

  4. Dynamics of Anisotropic Universes

    E-Print Network [OSTI]

    Jerome Perez

    2006-03-30T23:59:59.000Z

    We present a general study of the dynamical properties of Anisotropic Bianchi Universes in the context of Einstein General Relativity. Integrability results using Kovalevskaya exponents are reported and connected to general knowledge about Bianchi dynamics. Finally, dynamics toward singularity in Bianchi type VIII and IX universes are showed to be equivalent in some precise sence.

  5. Social Dynamics Introduction

    E-Print Network [OSTI]

    Barrett, Jeffrey A.

    Social Dynamics Introduction Part I: Correlation and the Social Contract Introduction to part I 1: University of Utah Press. 47-69. Part II: Importance of Dynamics Introduction to part II 1. Trust, Risk Significance of Some Simple Evolutionary Models (2000) Philosophy of Science 67: 94-113. 4. Dynamics

  6. Atmospheric Dynamics II Instructor

    E-Print Network [OSTI]

    AT602 Atmospheric Dynamics II 2 credits Instructor: David W. J. Thompson davet: An Introduction to Dynamic Meteorology, 5th Edition, Academic Press (recommended) · Marshall, J., and Plumb, R. A., 2008: Atmosphere, Ocean, and Climate Dynamics: An Introductory Text, Academic Press. · Vallis, G. K

  7. Intramolecular and nonlinear dynamics

    SciTech Connect (OSTI)

    Davis, M.J. [Argonne National Laboratory, IL (United States)

    1993-12-01T23:59:59.000Z

    Research in this program focuses on three interconnected areas. The first involves the study of intramolecular dynamics, particularly of highly excited systems. The second area involves the use of nonlinear dynamics as a tool for the study of molecular dynamics and complex kinetics. The third area is the study of the classical/quantum correspondence for highly excited systems, particularly systems exhibiting classical chaos.

  8. Cybersecurity Dynamics Shouhuai Xu

    E-Print Network [OSTI]

    Xu, Shouhuai

    Antonio ABSTRACT We explore the emerging field of Cybersecurity Dynamics, a candidate foundation been driving the study of security for decades -- the idea of cybersecurity dynamics emergedCybersecurity Dynamics Shouhuai Xu Department of Computer Science, University of Texas at San

  9. 17. METAPOPULATION DYNAMICS OF

    E-Print Network [OSTI]

    17. METAPOPULATION DYNAMICS OF INFECTIOUS DISEASES Matt J. Keeling, Ottar N. Bjørnstad, and Bryan T resonances for the dynamics of parasites. This is particularly true for microparasitic infections" growth of the parasite population. Thus, at the scale of the host popu- lation, infectious dynamics bears

  10. Molecular dynamics studies of the size and temperature dependence of the kinetics of freezing of Fe nanoparticles

    SciTech Connect (OSTI)

    Zhao, Bo; Huang, Jinfan, E-mail: jinfanh@umich.edu; Bartell, Lawrence S.

    2013-11-15T23:59:59.000Z

    Molecular dynamics (MD) computer simulations have been carried out and a novel modified technique of Voronoi polyhedra has been performed to identify solid-like particles in a molten nanoparticle. This technique works quite well in analyzing the effects of particle size on nucleation rates of iron nanoparticles in the temperature range of 750–1160 K. Nanoparticles with 1436 and 2133 Fe atoms have been examined and the results are compared with those obtained earlier with Fe{sub 331} nanoparticles. Nucleation rates for freezing obtained from MD simulations for Fe{sub 2133} vary from 8.8×10{sup 34} m{sup 3}/s to 4.1×10{sup 35} m{sup 3}/s at over a temperature range from 1160 K to 900 K, Rates for. Fe{sub 1436} and Fe{sub 331} are somewhat higher. Nucleation rates increase as supercooling deepens until the viscosity of the liquid increases sharply enough to slow down the rate. Bt applying classical nucleation theory, the interfacial free energy between solid and liquid cab be estimated From this and other thermodynamic information can be derived a theoretical expression for the size-dependence of the heat of fusion of nanoparticles. Results agreed quite well with those observed in our MD observations. An earlier expression in the literature for this size-dependence was shown to be incorrect. The size dependence of melting point is discussed. - Graphical abstract: Critical nuclei of crystallization. Display Omitted - Highlights: • Solid state material synthesis. • Material structure. • Experimental study of nucleation in condensed materials. • Computation study of nucleation in condensed materials.

  11. Prediction of Thermal Conductivity for Irradiated SiC/SiC Composites by Informing Continuum Models with Molecular Dynamics Data

    SciTech Connect (OSTI)

    Nguyen, Ba Nghiep; Gao, Fei; Henager, Charles H.; Kurtz, Richard J.

    2014-05-01T23:59:59.000Z

    This article proposes a new method to estimate the thermal conductivity of SiC/SiC composites subjected to neutron irradiation. The modeling method bridges different scales from the atomic scale to the scale of a 2D SiC/SiC composite. First, it studies the irradiation-induced point defects in perfect crystalline SiC using molecular dynamics (MD) simulations to compute the defect thermal resistance as a function of vacancy concentration and irradiation dose. The concept of defect thermal resistance is explored explicitly in the MD data using vacancy concentrations and thermal conductivity decrements due to phonon scattering. Point defect-induced swelling for chemical vapor deposited (CVD) SiC as a function of irradiation dose is approximated by scaling the corresponding MD results for perfect crystal ?-SiC to experimental data for CVD-SiC at various temperatures. The computed thermal defect resistance, thermal conductivity as a function of grain size, and definition of defect thermal resistance are used to compute the thermal conductivities of CVD-SiC, isothermal chemical vapor infiltrated (ICVI) SiC and nearly-stoichiometric SiC fibers. The computed fiber and ICVI-SiC matrix thermal conductivities are then used as input for an Eshelby-Mori-Tanaka approach to compute the thermal conductivities of 2D SiC/SiC composites subjected to neutron irradiation within the same irradiation doses. Predicted thermal conductivities for an irradiated Tyranno-SA/ICVI-SiC composite are found to be comparable to available experimental data for a similar composite ICVI-processed with these fibers.

  12. Molecular dynamics simulation of diffusion coefficients and structural properties of some alkylbenzenes in supercritical carbon dioxide at infinite dilution

    SciTech Connect (OSTI)

    Wang, Jinyang; Zhong, Haimin; Qiu, Wenda; Chen, Liuping, E-mail: cesclp@mail.sysu.edu.cn [KLGHEI of Environment and Energy Chemistry, School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou 510275 (China)] [KLGHEI of Environment and Energy Chemistry, School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Feng, Huajie [School of Chemistry and Chemical Engineering, Hainan Normal University, Haikou 571158 (China)] [School of Chemistry and Chemical Engineering, Hainan Normal University, Haikou 571158 (China)

    2014-03-14T23:59:59.000Z

    The binary infinite dilute diffusion coefficients, D{sub 12}{sup ?}, of some alkylbenzenes (Ph-C{sub n}, from Ph-H to Ph-C{sub 12}) from 313 K to 333 K at 15 MPa in supercritical carbon dioxide (scCO{sub 2}) have been studied by molecular dynamics (MD) simulation. The MD values agree well with the experimental ones, which indicate MD simulation technique is a powerful way to predict and obtain diffusion coefficients of solutes in supercritical fluids. Besides, the local structures of Ph-C{sub n}/CO{sub 2} fluids are further investigated by calculating radial distribution functions and coordination numbers. It qualitatively convinces that the first solvation shell of Ph-C{sub n} in scCO{sub 2} is significantly influenced by the structure of Ph-C{sub n} solute. Meanwhile, the mean end-to-end distance, the mean radius of gyration and dihedral angle distribution are calculated to gain an insight into the structural properties of Ph-C{sub n} in scCO{sub 2}. The abnormal trends of radial distribution functions and coordination numbers can be reasonably explained in term of molecular flexibility. Moreover, the computed results of dihedral angle clarify that flexibility of long-chain Ph-C{sub n} is the result of internal rotation of C-C single bond (?{sub c-c}) in alkyl chain. It is interesting that compared with n-alkane, because of the existence of benzene ring, the flexibility of alkyl chain in Ph-C{sub n} with same carbon atom number is significantly reduced, as a result, the carbon chain dependence of diffusion behaviors for long-chain n-alkane (n ? 5) and long-chain Ph-C{sub n} (n ? 4) in scCO{sub 2} are different.

  13. Molecular dynamics simulations of grain boundary thermal resistance in UO2

    SciTech Connect (OSTI)

    Tianyi Chen; Di Chen; Bulent H. Sencer; Lin Shao

    2014-09-01T23:59:59.000Z

    By means of molecular dynamics (MD) simulations, we have calculated Kaptiza resistance of UO2 with or without radiation damage. For coincident site lattice boundaries of different configurations, the boundary thermal resistance of unirradiated UO2 can be well described by a parameter-reduced formula by using boundary energies as variables. We extended the study to defect-loaded UO2 by introducing damage cascades in close vicinity to the boundaries. Following cascade annealing and defect migrations towards grain boundaries, the boundary energy increases and so does Kaptiza resistance. The correlations between these two still follow the same formula extracted from the unirradiated UO2. The finding will benefit multi-scale modeling of UO2 thermal properties under extreme radiation conditions by combining effects from boundary configurations and damage levels.

  14. Optimized Dynamical Decoupling in ?-Type n-Level Quantum Systems

    E-Print Network [OSTI]

    Linping Chan; Shuang Cong

    2014-04-28T23:59:59.000Z

    In this paper, we first design a type of Bang-Bang (BB) operation group to reduce the phase decoherence in a {\\Xi}-type n-level quantum system based on the dynamical decoupling mechanism. Then, we derive two kinds of dynamical decoupling schemes: periodic dynamical decoupling (PDD) and Uhrig dynamical decoupling (UDD). We select the non-diagonal element of density matrix as a reference index, and investigate the behavior of quantum coherence of the {\\Xi}-type n-level atom under these two dynamical decoupling schemes proposed. At last, we choose a {\\Xi}-type six-level atom as a system controlled, and use the decoupling schemes proposed to suppress the phase decoherence. The simulation experiments and the comparison results are given.

  15. First principles molecular dynamics without self-consistent field optimization

    E-Print Network [OSTI]

    Souvatzis, Petros

    2013-01-01T23:59:59.000Z

    We present a first principles molecular dynamics approach that is based on time-reversible ex- tended Lagrangian Born-Oppenheimer molecular dynamics [Phys. Rev. Lett. 100, 123004 (2008)] in the limit of vanishing self-consistent field optimization. The optimization-free dynamics keeps the computational cost to a minimum and typically provides molecular trajectories that closely follow the exact Born-Oppenheimer potential energy surface. Only one single diagonalization and Hamiltonian (or Fockian) costruction are required in each integration time step. The proposed dy- namics is derived for a general free-energy potential surface valid at finite electronic temperatures within hybrid density functional theory. Even in the event of irregular functional behavior that may cause a dynamical instability, the optimization-free limit represents an ideal starting guess for force calculations that may require a more elaborate iterative electronic ground state optimization. Our optimization-free dynamics thus represents ...

  16. Tubulin cofactor B regulates microtubule densities during microglia transition to the reactive states

    SciTech Connect (OSTI)

    Fanarraga, M.L. [Departamentos de Biologia Molecular, Universidad de Cantabria, IFIMAV. Herrera Oria s/n. 39011, Santander (Spain)], E-mail: fanarrag@unican.es; Villegas, J.C. [Anatomia y Biologia Celular, Universidad de Cantabria, IFIMAV. Herrera Oria s/n. 39011, Santander (Spain); Carranza, G.; Castano, R.; Zabala, J.C. [Departamentos de Biologia Molecular, Universidad de Cantabria, IFIMAV. Herrera Oria s/n. 39011, Santander (Spain)

    2009-02-01T23:59:59.000Z

    Microglia are highly dynamic cells of the CNS that continuously survey the welfare of the neural parenchyma and play key roles modulating neurogenesis and neuronal cell death. In response to injury or pathogen invasion parenchymal microglia transforms into a more active cell that proliferates, migrates and behaves as a macrophage. The acquisition of these extra skills implicates enormous modifications of the microtubule and actin cytoskeletons. Here we show that tubulin cofactor B (TBCB), which has been found to contribute to various aspects of microtubule dynamics in vivo, is also implicated in microglial cytoskeletal changes. We find that TBCB is upregulated in post-lesion reactive parenchymal microglia/macrophages, in interferon treated BV-2 microglial cells, and in neonate amoeboid microglia where the microtubule densities are remarkably low. Our data demonstrate that upon TBCB downregulation both, after microglia differentiation to the ramified phenotype in vivo and in vitro, or after TBCB gene silencing, microtubule densities are restored in these cells. Taken together these observations support the view that TBCB functions as a microtubule density regulator in microglia during activation, and provide an insight into the understanding of the complex mechanisms controlling microtubule reorganization during microglial transition between the amoeboid, ramified, and reactive phenotypes.

  17. Slow dynamics and anomalous nonlinear fast dynamics in diverse solids

    E-Print Network [OSTI]

    Slow dynamics and anomalous nonlinear fast dynamics in diverse solids Paul Johnsona) Geophysics study of anomalous nonlinear fast dynamics and slow dynamics in a number of solids. Observations are presented from seven diverse materials showing that anomalous nonlinear fast dynamics ANFD and slow dynamics

  18. Nonlinear Dynamics and Structure Formation in Complex Systems

    E-Print Network [OSTI]

    Zonca, Fulvio

    Condition · In burning plasmas ignition condition is reached when local power density (self-heating the ignition condition (-particle self-heating) #12;Nonlinear Dynamics and Structure Formation in Complex of charged fusion products · -particle self-heating may be lost due to their transport out of the system

  19. COMPUTATIONAL FLUID DYNAMICS MODELING OF SOLID OXIDE FUEL CELLS

    E-Print Network [OSTI]

    COMPUTATIONAL FLUID DYNAMICS MODELING OF SOLID OXIDE FUEL CELLS Ugur Pasaogullari and Chao-dimensional model has been developed to simulate solid oxide fuel cells (SOFC). The model fully couples current density operation. INTRODUCTION Solid oxide fuel cells (SOFC) are among possible candidates

  20. Dynamics of the Thermohaline Circulation under Wind Forcing

    E-Print Network [OSTI]

    Dynamics of the Thermohaline Circulation under Wind Forcing Hongjun Gao and Jinqiao Duan ¡ 1 external wind forcing. We show that, when there is no wind forcing, the stream function and the density. With rapidly oscillating wind forcing, we obtain an averaging principle for the thermohaline circulation model

  1. Dynamics of the Thermohaline Circulation under Wind Forcing

    E-Print Network [OSTI]

    Dynamics of the Thermohaline Circulation under Wind Forcing Hongjun Gao 1 and Jinqiao Duan 2 1 external wind forcing. We show that, when there is no wind forcing, the stream function and the density. With rapidly oscillating wind forcing, we obtain an averaging principle for the thermohaline circulation model

  2. ARBITRARY LAGRANGIAN-EULERIAN (ALE) METHODS IN COMPRESSIBLE FLUID DYNAMICS

    E-Print Network [OSTI]

    Kurien, Susan

    · . Scalar quantities (density , pressure p, specific internal energy and temperature T) are approximated Lagrangian system is numerically treated by compatible method [8, 9] conserving total energy. Several types Lagrangian-Eulerian (ALE [1]) code for simulation of problems in compressible fluid dynamics and plasma

  3. Dynamic Simulation of DFIG Wind Turbines on FPGA Boards

    E-Print Network [OSTI]

    Zambreno, Joseph A.

    Dynamic Simulation of DFIG Wind Turbines on FPGA Boards Hao Chen, Student Member, IEEE, Song Sun is a friction coefficient. The wind turbine model is based on the relation between the upstream wind speed V w + 1 where p is the air density; Rw is the wind turbine radius; cp (A, (3) is the performance

  4. Dynamic Particle Coupling for GPU-based Fluid Simulation

    E-Print Network [OSTI]

    Blanz, Volker

    -vi ¯j 2 W( Pi -Pj ,h). Here pj = k( ¯j - 0) is the pressure with gas constant k and rest density 0 for modeling dynamic particle coupling solely based on individual particle contributions. This technique does and µ is the fluid viscosity constant. To model the surface tension, M¨uller et.al. [MCG03] use the so

  5. Symmetry energy in nuclear density functional theory

    E-Print Network [OSTI]

    W. Nazarewicz; P. -G. Reinhard; W. Satula; D. Vretenar

    2013-07-22T23:59:59.000Z

    The nuclear symmetry energy represents a response to the neutron-proton asymmetry. In this survey we discuss various aspects of symmetry energy in the framework of nuclear density functional theory, considering both non-relativistic and relativistic self-consistent mean-field realizations side-by-side. Key observables pertaining to bulk nucleonic matter and finite nuclei are reviewed. Constraints on the symmetry energy and correlations between observables and symmetry-energy parameters, using statistical covariance analysis, are investigated. Perspectives for future work are outlined in the context of ongoing experimental efforts.

  6. Method of high-density foil fabrication

    DOE Patents [OSTI]

    Blue, Craig A.; Sikka, Vinod K.; Ohriner, Evan K.

    2003-12-16T23:59:59.000Z

    A method for preparing flat foils having a high density includes the steps of mixing a powdered material with a binder to form a green sheet. The green sheet is exposed to a high intensity radiative source adapted to emit radiation of wavelengths corresponding to an absorption spectrum of the powdered material. The surface of the green sheet is heated while a lower sub-surface temperature is maintained. An apparatus for preparing a foil from a green sheet using a radiation source is also disclosed.

  7. Generalized Holographic Quantum Criticality at Finite Density

    E-Print Network [OSTI]

    B. Goutéraux; E. Kiritsis

    2013-01-23T23:59:59.000Z

    We show that the near-extremal solutions of Einstein-Maxwell-Dilaton theories, studied in ArXiv:1005.4690, provide IR quantum critical geometries, by embedding classes of them in higher-dimensional AdS and Lifshitz solutions. This explains the scaling of their thermodynamic functions and their IR transport coefficients, the nature of their spectra, the Gubser bound, and regulates their singularities. We propose that these are the most general quantum critical IR asymptotics at finite density of EMD theories.

  8. Particle transport inferences from density sawteeth

    SciTech Connect (OSTI)

    Chen, J.; Li, Q.; Zhuang, G. [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan 430074 (China); Liao, K.; Gentle, K. W., E-mail: k.gentle@mail.utexas.edu [Institute for Fusion Studies, University of Texas, Austin, Texas 78712 (United States)

    2014-05-15T23:59:59.000Z

    Sawtooth oscillations in tokamaks are defined by their effect on electron temperature: a rapid flattening of the core profile followed by an outward heat pulse and a slow core recovery caused by central heating. Recent high-resolution, multi-chord interferometer measurements on JTEXT extend these studies to particle transport. Sawteeth only partially flatten the core density profile, but enhanced particle diffusion on the time scale of the thermal crash occurs over much of the profile, relevant for impurities. Recovery between crashes implies an inward pinch velocity extending to the center.

  9. Low density inorganic foams fabricated using microwaves

    SciTech Connect (OSTI)

    Meek, T.T.; Blake, R.D.; Gregory, T.G.

    1985-01-01T23:59:59.000Z

    The objective of our work was to determine if high temperature foams could be made using microwave heating; and if so, to investigate some of their properties. Several foams were made and their compressive strengths, tensile strengths and densities were determined. Foams were made of glass, metal-glass, glass-fiber, metal-glass-fiber, and fly ash. The microwave source used was a Litton model 1521 microwave oven which operated at 2.45 GHz and had an output of 700 watts.

  10. Nuclear Energy Density Optimization: UNEDF2

    E-Print Network [OSTI]

    M. Kortelainen; J. McDonnell; W. Nazarewicz; E. Olsen; P. -G. Reinhard; J. Sarich; N. Schunck; S. M. Wild; D. Davesne; J. Erler; A. Pastore

    2014-10-30T23:59:59.000Z

    The parameters of the UNEDF2 nuclear energy density functional (EDF) model were obtained in an optimization to experimental data consisting of nuclear binding energies, proton radii, odd-even mass staggering data, fission-isomer excitation energies, and single particle energies. In addition to parameter optimization, sensitivity analysis was done to obtain parameter uncertainties and correlations. The resulting UNEDF2 is an all-around EDF. However, the sensitivity analysis also demonstrated that the limits of current Skyrme-like EDFs have been reached and that novel approaches are called for.

  11. Wigner density of a rigid rotator

    SciTech Connect (OSTI)

    Malta, C.P. [Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66318, 05315-970 Sao Paulo (Brazil)] [Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66318, 05315-970 Sao Paulo (Brazil); Marshall, T.S. [Department of Mathematics, University of Manchester, Manchester M139PL (United Kingdom)] [Department of Mathematics, University of Manchester, Manchester M139PL (United Kingdom); Santos, E. [Departamento de Fisica Moderna, Universidad de Cantabria, 39005, Santander (Spain)] [Departamento de Fisica Moderna, Universidad de Cantabria, 39005, Santander (Spain)

    1997-03-01T23:59:59.000Z

    We show that the Wigner density of the rigid rotator, in an appropriate, i.e., four-dimensional, phase space, is positive. This result holds in the ground state (S state), and also in the thermal mixture state at all finite temperatures. We discuss the implications of our result for the description of angular momentum in quantum mechanics; in particular, we reexamine, in the light of this new evidence, the suggestion made by Einstein and Stern [Ann. Phys. {bold 40}, 551 (1913)] that there is a nontrivial distribution of angular momentum in the S state. {copyright} {ital 1997} {ital The American Physical Society}

  12. High Energy Density Ultracapacitors | Department of Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn't YourTransport(Fact Sheet), GeothermalGridHYDROGEN TOTechnologyHigh Efficiency Low -1 DOE

  13. High Energy Density Ultracapacitors | Department of Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn't YourTransport(Fact Sheet), GeothermalGridHYDROGEN TOTechnologyHigh Efficiency Low -1 DOE0 DOE

  14. High Energy Density Ultracapacitors | Department of Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn't YourTransport(Fact Sheet), GeothermalGridHYDROGEN TOTechnologyHigh Efficiency Low -1 DOE0 DOE09

  15. Material dynamics under extreme conditions of pressure and strain rate

    SciTech Connect (OSTI)

    Remington, B A; Allen, P; Bringa, E; Hawreliak, J; Ho, D; Lorenz, K T; Lorenzana, H; Meyers, M A; Pollaine, S W; Rosolankova, K; Sadik, B; Schneider, M S; Swift, D; Wark, J; Yaakobi, B

    2005-09-06T23:59:59.000Z

    Solid state experiments at extreme pressures (10-100 GPa) and strain rates ({approx}10{sup 6}-10{sup 8}s{sup -1}) are being developed on high-energy laser facilities, and offer the possibility for exploring new regimes of materials science. These extreme solid-state conditions can be accessed with either shock loading or with a quasi-isentropic ramped pressure drive. Velocity interferometer measurements establish the high pressure conditions. Constitutive models for solid-state strength under these conditions are tested by comparing 2D continuum simulations with experiments measuring perturbation growth due to the Rayleigh-Taylor instability in solid-state samples. Lattice compression, phase, and temperature are deduced from extended x-ray absorption fine structure (EXAFS) measurements, from which the shock-induced {alpha}-{omega} phase transition in Ti and the {alpha}-{var_epsilon} phase transition in Fe are inferred to occur on sub-nanosec time scales. Time resolved lattice response and phase can also be measured with dynamic x-ray diffraction measurements, where the elastic-plastic (1D-3D) lattice relaxation in shocked Cu is shown to occur promptly (< 1 ns). Subsequent large-scale molecular dynamics (MD) simulations elucidate the microscopic dynamics that underlie the 3D lattice relaxation. Deformation mechanisms are identified by examining the residual microstructure in recovered samples. The slip-twinning threshold in single-crystal Cu shocked along the [001] direction is shown to occur at shock strengths of {approx}20 GPa, whereas the corresponding transition for Cu shocked along the [134] direction occurs at higher shock strengths. This slip-twinning threshold also depends on the stacking fault energy (SFE), being lower for low SFE materials. Designs have been developed for achieving much higher pressures, P > 1000 GPa, in the solid state on the National Ignition Facility (NIF) laser.

  16. Spatiotemporal Dynamics of Online Motor Correction Processing Revealed by High-density Electroencephalography

    E-Print Network [OSTI]

    Dipietro, Laura

    The ability to control online motor corrections is key to dealing with unexpected changes arising in the environment with which we interact. How the CNS controls online motor corrections is poorly understood, but evidence ...

  17. Dynamics of coastal cod populations: intra-and intercohort density dependence

    E-Print Network [OSTI]

    -temporal patterns in the abundance of cod along the Norwegian Skagerrak coast and demonstrated signi¢cant cyclicity populations (Gadus morhua L.) on the basis of the long-term monitoring data from the Norwegian Skagerrak coast

  18. Dynamics of Charge-Transfer Processes with Time-Dependent Density Functional Theory

    E-Print Network [OSTI]

    (organic, inorganic, and hybrids), photocatalysis, biomolecules in solvents, reactions at the interface

  19. Radiation in molecular dynamic simulations

    SciTech Connect (OSTI)

    Glosli, J; Graziani, F; More, R; Murillo, M; Streitz, F; Surh, M

    2008-10-13T23:59:59.000Z

    Hot dense radiative (HDR) plasmas common to Inertial Confinement Fusion (ICF) and stellar interiors have high temperature (a few hundred eV to tens of keV), high density (tens to hundreds of g/cc) and high pressure (hundreds of Megabars to thousands of Gigabars). Typically, such plasmas undergo collisional, radiative, atomic and possibly thermonuclear processes. In order to describe HDR plasmas, computational physicists in ICF and astrophysics use atomic-scale microphysical models implemented in various simulation codes. Experimental validation of the models used to describe HDR plasmas are difficult to perform. Direct Numerical Simulation (DNS) of the many-body interactions of plasmas is a promising approach to model validation but, previous work either relies on the collisionless approximation or ignores radiation. We present a new numerical simulation technique to address a currently unsolved problem: the extension of molecular dynamics to collisional plasmas including emission and absorption of radiation. The new technique passes a key test: it relaxes to a blackbody spectrum for a plasma in local thermodynamic equilibrium. This new tool also provides a method for assessing the accuracy of energy and momentum exchange models in hot dense plasmas. As an example, we simulate the evolution of non-equilibrium electron, ion, and radiation temperatures for a hydrogen plasma using the new molecular dynamics simulation capability.

  20. Dynamics of the Galaxy's Satellites

    E-Print Network [OSTI]

    James Binney

    2000-06-28T23:59:59.000Z

    The Milky Way's satellites provide unique information about the density of the Galactic halo at large radii. The inclusion of even a few rather inaccurate proper motions resolves an ambiguity in older mass estimates in favour of higher values. Many of the satellites are concentrated into streams. The dynamics of the Magellanic Stream provided an early indication that the halo reaches out to beyond 100 kpc. Tidal forces between the Clouds are currently disturbing the Clouds' internal dynamics. One would expect this damage to worsen rapidly as the tidal field of the MW excites the eccentricity of the Clouds' mutual orbit. This process, which has yet to be completely modelled, is important for understanding the degree of self-lensing in searches for gravitational lensing events. The Sagittarius Dwarf galaxy very likely contributes significantly to the Galactic warp. The direction of the warp's line of nodes is incorrectly predicted by the simplest models of the Dwarf's orbit. More sophisticated models, in which a complex distribution of stripped dark matter is predicted, may be more successful.

  1. The density of states approach for the simulation of finite density quantum field theories

    E-Print Network [OSTI]

    K. Langfeld; B. Lucini; A. Rago; R. Pellegrini; L. Bongiovanni

    2015-03-02T23:59:59.000Z

    Finite density quantum field theories have evaded first principle Monte-Carlo simulations due to the notorious sign-problem. The partition function of such theories appears as the Fourier transform of the generalised density-of-states, which is the probability distribution of the imaginary part of the action. With the advent of Wang-Landau type simulation techniques and recent advances, the density-of-states can be calculated over many hundreds of orders of magnitude. Current research addresses the question whether the achieved precision is high enough to reliably extract the finite density partition function, which is exponentially suppressed with the volume. In my talk, I review the state-of-play for the high precision calculations of the density-of-states as well as the recent progress for obtaining reliable results from highly oscillating integrals. I will review recent progress for the $Z_3$ quantum field theory for which results can be obtained from the simulation of the dual theory, which appears to free of a sign problem.

  2. Impact of Dynamical Fermions on QCD Vacuum Structure

    E-Print Network [OSTI]

    Peter J. Moran; Derek B. Leinweber

    2008-01-14T23:59:59.000Z

    We examine how dynamical fermions affect both the UV and infrared structure of the QCD vacuum. We consider large $28^3 \\times 96$ lattices from the MILC collaboration, using a gluonic definition of the topological charge density, founded on a new over-improved stout-link smearing algorithm. The algorithm reproduces established results from the overlap formalism and is designed to preserve nontrivial topological objects including instantons. At short distances we focus on the topological charge correlator, $$, where negative values at small $x$ reveal a sign-alternating layered structure to the topological-charge density of the QCD vacuum. We find that the magnitudes of the negative dip in the $$ correlator and the positive $$ contact term are both increased with the introduction of dynamical fermion degrees of freedom. This is in accord with expectations based on charge renormalization and the vanishing of the topological susceptibility in the chiral limit. At large distances we examine the extent to which instanton-like objects are found on the lattice, and how their distributions vary between quenched and dynamical gauge fields. We show that dynamical gauge fields contain more instanton-like objects with an average size greater than in the quenched vacuum. Finally, we directly visualize the topological charge density in order to investigate the effects of dynamical sea-quark degrees of freedom on topology.

  3. Dynamical friction in modified Newtonian dynamics

    E-Print Network [OSTI]

    C. Nipoti; L. Ciotti; J. Binney; P. Londrillo

    2008-03-31T23:59:59.000Z

    We have tested a previous analytical estimate of the dynamical friction timescale in Modified Newtonian Dynamics (MOND) with fully non-linear N-body simulations. The simulations confirm that the dynamical friction timescale is significantly shorter in MOND than in equivalent Newtonian systems, i.e. systems with the same phase-space distribution of baryons and additional dark matter. An apparent conflict between this result and the long timescales determined for bars to slow and mergers to be completed in previous N-body simulations of MOND systems is explained. The confirmation of the short dynamical-friction timescale in MOND underlines the challenge that the Fornax dwarf spheroidal poses to the viability of MOND.

  4. A Relativistic Dynamical Collapse Model

    E-Print Network [OSTI]

    Philip Pearle

    2014-12-21T23:59:59.000Z

    A model is discussed where all operators are constructed from a quantum scalar field whose energy spectrum takes on all real values. The Schr\\"odinger picture wave function depends upon space and time coordinates for each particle, as well as an inexorably increasing evolution parameter $s$ which labels a foliation of space-like hypersurfaces. The model is constructed to be manifestly Lorentz invariant in the interaction picture. Free particle states and interactions are discussed in this framework. Then, the formalism of the CSL (Continuous Spontaneous Localization) theory of dynamical collapse is applied. The collapse-generating operator is chosen to to be the particle number space-time density. Unlike previous relativistically invariant models, the vacuum state is not excited. The collapse dynamics depends upon two parameters, a parameter $\\Lambda$ which represents the collapse rate/volume and a scale factor $\\ell$. A common example of collapse dynamics, involving a clump of matter in a superposition of two locations, is analyzed. The collapse rate is shown to be identical to that of non-relativistic CSL when the GRW-CSL choice of $\\ell=a=10^{-5}$cm, is made, along with $\\Lambda=\\lambda/a^{3}$ (GRW-CSL choice $\\lambda=10^{-16}s^{-1}$). However, it is also shown that the change of mass of a nucleon over the age of the universe is then unacceptably large. The case where $\\ell$ is the size of the universe is then considered. It is shown that the collapse behavior is satisfactory and the change of mass over the age of the universe is acceptably small, when $\\Lambda= \\lambda/\\ell a^{2}$.

  5. High Energy Density Science at the Linac Coherent Light Source

    SciTech Connect (OSTI)

    Lee, R W

    2007-10-19T23:59:59.000Z

    High energy density science (HEDS), as a discipline that has developed in the United States from National Nuclear Security Agency (NNSA)-sponsored laboratory research programs, is, and will remain, a major component of the NNSA science and technology strategy. Its scientific borders are not restricted to NNSA. 'Frontiers in High Energy Density Physics: The X-Games of Contemporary Science' identified numerous exciting scientific opportunities in this field, while pointing to the need for a overarching interagency plan for its evolution. Meanwhile, construction of the first x-ray free-electron laser, the Office-of-Science-funded Linear Coherent Light Source-LCLS: the world's first free electron x-ray laser, with 100-fsec time resolution, tunable x-ray energies, a high rep rate, and a 10 order-of-magnitude increase in brightness over any other x-ray source--led to the realization that the scientific needs of NNSA and the broader scientific community could be well served by an LCLS HEDS endstation employing both short-pulse and high-energy optical lasers. Development of this concept has been well received in the community. NNSA requested a workshop on the applicability of LCLS to its needs. 'High Energy Density Science at the LCLS: NNSA Defense Programs Mission Need' was held in December 2006. The workshop provided strong support for the relevance of the endstation to NNSA strategic requirements. The range of science that was addressed covered a wide swath of the vast HEDS phase space. The unique possibilities provided by the LCLS in areas of intense interest to NNSA Defense Programs were discussed. The areas of focus included warm dense matter and equations of state, hot dense matter, and behavior of high-pressure materials under conditions of high strain-rate and extreme dynamic loading. Development of new and advanced diagnostic techniques was also addressed. This report lays out the relevant science, as brief summaries (Ch. II), expanded descriptions (Ch. V), and a more detailed plans for experiments (Ch. VI), highlighting the uniqueness the HEDS endstation will play in providing mission-relevant HED data and in the development of the field. One of the more exciting aspects of NNSA-relevant experiments on LCLS is that, given the extraordinary investment and consequent advances in accurate atomic-scale simulations of matter (to a large extent via the Accelerated Scientific Computing program sponsored by NNSA), the facility will provide a platform that, for the first time, will permit experiments in the regimes of interest at the time and spatial scales of the simulations. In Chapter III, the report places the potential of LCLS with an HED science endstation in the context of science required by NNSA, as well as explicating the relationship of NNSA and HED science in general. Chapter IV discusses 4th-generation light sources, like LCLS, in the context of other laboratory technologies presently utilized by NNSA. The report concludes, noting that an HED endstation on LCLS can provide access to data in regimes that are relevant to NNSA needs but no mechanism exists for providing such data. The endstation will also serve to build a broad-based community in the 'X-Games' of physics. The science generated by the facility will be a collaboration of NNSA-based laboratory scientists and university-based researchers. The LCLS endstation fulfills the need for an intermediate-scale facility capable of delivering fundamental advances and mission-relevant research in high energy density science.

  6. Measuring the entanglement of analogue Hawking radiation by the density-density correlation function

    E-Print Network [OSTI]

    Steinhauer, Jeff

    2015-01-01T23:59:59.000Z

    We theoretically study the entanglement of Hawking radiation emitted by an analogue black hole. We find that this entanglement can be measured by the experimentally accessible density-density correlation function, which only requires standard imaging techniques. It is seen that the high energy tail of the distribution of Hawking radiation should be entangled, whereas the low energy part is not. This confirms a previous numerical study. The full Peres-Horodecki criterion is considered, but a significant simplification is found in the stationary, homogeneous case. Our method applies to systems which are sufficiently cold that the thermal phonons can be neglected.

  7. Shock waves in a Z-pinch and the formation of high energy density plasma

    SciTech Connect (OSTI)

    Rahman, H. U. [Magneto-Inertial Fusion Technologies Inc. (MIFTI), Irvine, California 92612 (United States) and Department of Physics, University of California Irvine, Irvine, California 92697 (United States); Wessel, F. J. [Department of Physics, University of California Irvine, Irvine California 92697 (United States); Ney, P. [Mount San Jacinto College, Menifee, California 92584 (United States); Presura, R. [University of Nevada, Reno, 1664 N. Virginia St., Reno, Nevada 89557-0208 (United States); Ellahi, Rahmat [Department of Mathematics and Statistics, FBAS, IIU, Islamabad (Pakistan) and Department of Mechanical Engineering, University of California Riverside, Riverside, California 92521 (United States); Shukla, P. K. [Department of Mechanical and Aerospace Engineering and Center for Energy Research, University of California San Diego, La Jolla, California 92093 (United States)

    2012-12-15T23:59:59.000Z

    A Z-pinch liner, imploding onto a target plasma, evolves in a step-wise manner, producing a stable, magneto-inertial, high-energy-density plasma compression. The typical configuration is a cylindrical, high-atomic-number liner imploding onto a low-atomic-number target. The parameters for a terawatt-class machine (e.g., Zebra at the University of Nevada, Reno, Nevada Terawatt Facility) have been simulated. The 2-1/2 D MHD code, MACH2, was used to study this configuration. The requirements are for an initial radius of a few mm for stable implosion; the material densities properly distributed, so that the target is effectively heated initially by shock heating and finally by adiabatic compression; and the liner's thickness adjusted to promote radial current transport and subsequent current amplification in the target. Since the shock velocity is smaller in the liner, than in the target, a stable-shock forms at the interface, allowing the central load to accelerate magnetically and inertially, producing a magneto-inertial implosion and high-energy density plasma. Comparing the implosion dynamics of a low-Z target with those of a high-Z target demonstrates the role of shock waves in terms of compression and heating. In the case of a high-Z target, the shock wave does not play a significant heating role. The shock waves carry current and transport the magnetic field, producing a high density on-axis, at relatively low temperature. Whereas, in the case of a low-Z target, the fast moving shock wave preheats the target during the initial implosion phase, and the later adiabatic compression further heats the target to very high energy density. As a result, the compression ratio required for heating the low-Z plasma to very high energy densities is greatly reduced.

  8. Feasibility and preliminary design study for a high velocity, low density wind tunnel utilizing the thermal creep effect

    E-Print Network [OSTI]

    Stephen, Alton Lee

    1968-01-01T23:59:59.000Z

    Average molecular velocity Cartesian length co-ordinate Thermal accomodation co-efficient Constant used in Appendix I Element of volume in velocity space Angular displacement Viscosity co-efficient Gas density cm cm/sec cm/sec cm/sec cm... on spheres in a rarefied gas as a means of making correc- tions to the results of Millikan's oil drop experiment. 4 Sanger's work was followed by a paper in which Tsien out- lined the field of low density, high speed gas dynamics. In this work, Tsien used...

  9. Structure formation: a spherical model for the evolution of the density distribution

    E-Print Network [OSTI]

    P. Valageas

    1998-07-02T23:59:59.000Z

    Within the framework of hierarchical clustering we show that a simple Press-Schechter-like approximation, based on spherical dynamics, provides a good estimate of the evolution of the density field in the quasi-linear regime up to $\\Sigma \\sim 1$. Moreover, it allows one to recover the exact series of the cumulants of the probability distribution of the density contrast in the limit $\\Sigma \\to 0$ which sheds some light on the rigorous result and on ``filtering''. We also obtain similar results for the divergence of the velocity field. Next, we extend this prescription to the highly non-linear regime, using a stable-clustering approximation. Then we recover a specific scaling of the counts-in-cells which is indeed seen in numerical simulations, over a well-defined range. To this order we also introduce an explicit treatment of the behaviour of underdensities, which takes care of the normalization and is linked to the low-density bubbles and the walls one can see in numerical simulations. We compare this to a 1-dimensional adhesion model, and we present the consequences of our prescription for the power-law tail and the cutoff of the density distribution.

  10. $^{64}$Ni+$^{64}$Ni fusion reaction calculated with the density-constrained time-dependent Hartree-Fock formalism

    E-Print Network [OSTI]

    A. S. Umar; V. E. Oberacker

    2007-09-25T23:59:59.000Z

    We study fusion reactions of the $^{64}$Ni+$^{64}$Ni system using the density-constrained time-dependent Hartree-Fock (TDHF) formalism. In this formalism the fusion barriers are directly obtained from TDHF dynamics. In addition, we incorporate the entrance channel alignments of the slightly deformed (oblate) $^{64}$Ni nuclei due to dynamical Coulomb excitation. We show that alignment leads to a fusion barrier distribution and alters the naive picture for defining which energies are actually sub-barrier. We also show that core polarization effects could play a significant role in fusion cross section calculations.

  11. Backward Clusters, Hierarchy and Wild Sums for a Hard Sphere System in a Low-Density Regime

    E-Print Network [OSTI]

    K. Aoki; M. Pulvirenti; S. Simonella; T. Tsuji

    2014-08-27T23:59:59.000Z

    We study the statistics of backward clusters in a gas of hard spheres at low density. A backward cluster is defined as the group of particles involved directly or indirectly in the backwards-in-time dynamics of a given tagged sphere. We derive upper and lower bounds on the average size of clusters by using the theory of the homogeneous Boltzmann equation combined with suitable hierarchical expansions. These representations are known in the easier context of Maxwellian molecules (Wild sums). We test our results with a numerical experiment based on molecular dynamics simulations.

  12. Marking Streets to Improve Parking Density

    E-Print Network [OSTI]

    Xu, Chao

    2015-01-01T23:59:59.000Z

    Street parking spots for automobiles are a scarce commodity in most urban environments. The heterogeneity of car sizes makes it inefficient to rigidly define fixed-sized spots. Instead, unmarked streets in cities like New York leave placement decisions to individual drivers, who have no direct incentive to maximize street utilization. In this paper, we explore the effectiveness of two different behavioral interventions designed to encourage better parking, namely (1) educational campaigns to encourage parkers to "kiss the bumper" and reduce the distance between themselves and their neighbors, or (2) painting appropriately-spaced markings on the street and urging drivers to "hit the line". Through analysis and simulation, we establish that the greatest densities are achieved when lines are painted to create spots roughly twice the length of average-sized cars. Kiss-the-bumper campaigns are in principle more effective than hit-the-line for equal degrees of compliance, although we believe that the visual cues of...

  13. Ternary liquid mixture viscosities and densities

    SciTech Connect (OSTI)

    Wei, I.C.; Rowley, R.L.

    1984-01-01T23:59:59.000Z

    Liquid mixture viscosities and densities have been measured at 298.15 K and ambient pressure for 20 ternary systems. Twelve ternary compositions, encompassing the entire composition range, have been chosen for each system in an effort to test a newly proposed predictive equation based on local compositions. Viscosities calculated by using the local composition model agreed with the experimental data within an average absolute deviation of 6.4%. No adjustable parameters were used and only binary interactions in the form of NRTL constants were input. The results of these studies indicate that the local composition model predictions are generally as good for multicomponent systems as they are for the corresponding binaries. 24 references, 3 tables.

  14. Competition between superconductivity and spin density wave

    E-Print Network [OSTI]

    Tian De Cao

    2012-08-25T23:59:59.000Z

    The Hubbard model has been investigated widely by many authors, while this work may be new in two aspects. One, we focus on the possible effects of the positions of the gaps associated with the pairing and the spin density wave. Two, we suggest that the models with different parameters are appropriate for different materials (or a material in different doped regions). This will lead to some new insights into the high temperature superconductors. It is shown that the SDW can appear at some temperature region when the on-site Coulomb interaction is larger, while the SC requires a decreased U at a lower temperature. This can qualitatively explain the relationship between superconducting and pseudogap states of Cu-based superconductors in underdoped and optimally doped regions. The superinsulator is also discussed.

  15. Band terminations in density functional theory

    E-Print Network [OSTI]

    A. V. Afanasjev

    2009-02-01T23:59:59.000Z

    The analysis of the terminating bands has been performed in the relativistic mean field framework. It was shown that nuclear magnetism provides an additional binding to the energies of the specific configuration and this additional binding increases with spin and has its {\\it maximum} exactly at the terminating state. This suggests that the terminating states can be an interesting probe of the time-odd mean fields {\\it provided that other effects can be reliably isolated.} Unfortunately, a reliable isolation of these effects is not that simple: many terms of the density functional theories contribute into the energies of the terminating states and the deficiencies in the description of those terms affect the result. The recent suggestion \\cite{ZSW.05} that the relative energies of the terminating states in the $N \

  16. High energy density redox flow device

    DOE Patents [OSTI]

    Chiang, Yet-Ming; Carter, W. Craig; Ho, Bryan Y; Duduta, Mihai; Limthongkul, Pimpa

    2014-05-13T23:59:59.000Z

    Redox flow devices are described in which at least one of the positive electrode or negative electrode-active materials is a semi-solid or is a condensed ion-storing electroactive material, and in which at least one of the electrode-active materials is transported to and from an assembly at which the electrochemical reaction occurs, producing electrical energy. The electronic conductivity of the semi-solid is increased by the addition of conductive particles to suspensions and/or via the surface modification of the solid in semi-solids (e.g., by coating the solid with a more electron conductive coating material to increase the power of the device). High energy density and high power redox flow devices are disclosed. The redox flow devices described herein can also include one or more inventive design features. In addition, inventive chemistries for use in redox flow devices are also described.

  17. Laser scattering by density fluctuations of ultra-cold atoms in a magneto-optical trap

    E-Print Network [OSTI]

    J. T. Mendonça; H. Terças

    2011-04-06T23:59:59.000Z

    We study the spectrum of density fluctuations in the ultra-cold gas of neutral atoms, confined in a magneto-optical trap. We determine the corresponding amplitude and spectra of laser light scattered by this medium. We derive an expression for the dynamical structure function, by using a test particle method. We propose to use the collective laser scattering as a diagnostic method for the microscopic properties of the ultra-cold matter. This will also allow us to check on the atomic correlations which are mediated by the collective mean field inside the gas.

  18. Tuning Range-Separated Density Functional Theory for Photocatalytic Water Splitting Systems

    E-Print Network [OSTI]

    Bokareva, Olga S; Bokarev, Sergey I; Kühn, Oliver

    2015-01-01T23:59:59.000Z

    We discuss the applicability of long-range separated density functional theory (DFT) to the prediction of electronic transitions of a particular photocatalytic system based on an Ir(III) photosensitizer (IrPS). Special attention is paid to the charge-transfer properties which are of key importance for the photoexcitation dynamics, but and cannot be correctly described by means of conventional DFT. The optimization of the range-separation parameter is discussed for IrPS including its complexes with electron donors and acceptors used in photocatalysis. Particular attention is paid to the problems arising for a description of medium effects by a polarizable continuum model.

  19. Noisy Independent Factor Analysis Model for Density Estimation and Classification

    E-Print Network [OSTI]

    Amato, U.

    2009-06-09T23:59:59.000Z

    We consider the problem of multivariate density estimation when the unknown density is assumed to follow a particular form of dimensionality reduction, a noisy independent factor analysis (IFA) model. In this model the ...

  20. Experimental bond critical point and local energy density properties...

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

    Mn-O, Fe-O and Co-O bonded interactions for Abstract: Bond critical point, bcp, and local energy density properties for the electron density, ED, distributions, calculated with...