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1

Density-dependent covariant energy density functionals  

Science Conference Proceedings (OSTI)

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.

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

2012-10-20T23:59:59.000Z

2

Building a Universal Nuclear Energy Density Functional  

NLE Websites -- All DOE Office Websites (Extended Search)

Building a Universal Nuclear Energy Density Functional Building a Universal Nuclear Energy Density Functional VaryMatrix.png Collaboration with mathematicians and computational...

3

Some challenges for Nuclear Density Functional Theory  

E-Print Network (OSTI)

We discuss some of the challenges that the DFT community faces in its quest for the truly universal energy density functional applicable over the entire nuclear chart.

T. Duguet; K. Bennaceur; T. Lesinski; J. Meyer

2006-06-20T23:59:59.000Z

4

Instabilities in the Nuclear Energy Density Functional  

E-Print Network (OSTI)

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.

M. Kortelainen; T. Lesinski

2010-02-05T23:59:59.000Z

5

Velocity Probability Density Functions for Oceanic Floats  

Science Conference Proceedings (OSTI)

Probability density functions (PDFs) of daily velocities from subsurface floats deployed in the North Atlantic and equatorial Atlantic Oceans are examined. In general, the PDFs are approximately Gaussian for small velocities, but with significant ...

Annalisa Bracco; J. H. LaCasce; Antonello Provenzale

2000-03-01T23:59:59.000Z

6

Velocity Probability Density Functions from Altimetry  

Science Conference Proceedings (OSTI)

Probability density functions (pdfs) are employed to evaluate the distribution of velocities in the global ocean. This study computes pdfs of ocean surface velocity using altimetric data from the TOPEX/Poseidon satellite. Results show that the ...

Sarah T. Gille; Stefan G. Llewellyn Smith

2000-01-01T23:59:59.000Z

7

Density and pair-density scaling for deriving the Euler equation in density-functional and pair-density-functional theory  

Science Conference Proceedings (OSTI)

A link between density and pair density functional theories is presented. Density and pair density scaling are used to derive the Euler equation in both theories. Density scaling provides a constructive way of obtaining approximations for the Pauli potential. The Pauli potential (energy) of the density functional theory is expressed as the difference of the scaled and original exchange-correlation potentials (energies).

Nagy, A. [Department of Theoretical Physics, University of Debrecen, H-4010 Debrecen (Hungary)

2011-09-15T23:59:59.000Z

8

Md. Saifur Rahaman Md. Saifur Rahaman  

E-Print Network (OSTI)

of Chemical and Environmental Engineering "Environmental Applications of Nanotechnology" Advisor: ProfMd. Saifur Rahaman Resume 1 Md. Saifur Rahaman Department of Chemical and Environmental Engineering from Wastewater through Struvite Crystallization in a Fluidized Bed Reactor: Kinetics, Hydrodynamics

Elimelech, Menachem

9

Local Restaurants - Gaithersburg, MD  

Science Conference Proceedings (OSTI)

... Subway 16 Bureau Dr. Gaithersburg, MD (301) 527-8988. Thai Tanium 657 Center Point Way Gaithersburg, MD (301) 990-3699. ...

2013-07-25T23:59:59.000Z

10

Thermal Density Functional Theory in Context  

E-Print Network (OSTI)

This chapter introduces thermal density functional theory, starting from the ground-state theory and assuming a background in quantum mechanics and statistical mechanics. We review the foundations of density functional theory (DFT) by illustrating some of its key reformulations. The basics of DFT for thermal ensembles are explained in this context, as are tools useful for analysis and development of approximations. We close by discussing some key ideas relating thermal DFT and the ground state. This review emphasizes thermal DFT's strengths as a consistent and general framework.

Pribram-Jones, Aurora; Gross, E K U; Burke, Kieron

2013-01-01T23:59:59.000Z

11

Density Functional Theory Approach to Nuclear Fission  

E-Print Network (OSTI)

The Skyrme nuclear energy density functional theory (DFT) is used to model neutron-induced fission in actinides. This paper focuses on the numerical implementation of the theory. In particular, it reports recent advances in DFT code development on leadership class computers, and presents a detailed analysis of the numerical accuracy of DFT solvers for near-scission calculations.

N. Schunck

2012-12-13T23:59:59.000Z

12

Nuclear fission in covariant density functional theory  

E-Print Network (OSTI)

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.

A. V. Afanasjev; H. Abusara; P. Ring

2013-09-12T23:59:59.000Z

13

Symmetry energy in nuclear density functional theory  

E-Print Network (OSTI)

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.

W. Nazarewicz; P. -G. Reinhard; W. Satula; D. Vretenar

2013-07-22T23:59:59.000Z

14

Symmetry energy in nuclear density functional theory  

E-Print Network (OSTI)

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.

Nazarewicz, W; Satula, W; Vretenar, D

2013-01-01T23:59:59.000Z

15

The nuclear energy density functional formalism  

E-Print Network (OSTI)

The present document focuses on the theoretical foundations of the nuclear energy density functional (EDF) method. As such, it does not aim at reviewing the status of the field, at covering all possible ramifications of the approach or at presenting recent achievements and applications. The objective is to provide a modern account of the nuclear EDF formalism that is at variance with traditional presentations that rely, at one point or another, on a {\\it Hamiltonian-based} picture. The latter is not general enough to encompass what the nuclear EDF method represents as of today. Specifically, the traditional Hamiltonian-based picture does not allow one to grasp the difficulties associated with the fact that currently available parametrizations of the energy kernel $E[g',g]$ at play in the method do not derive from a genuine Hamilton operator, would the latter be effective. The method is formulated from the outset through the most general multi-reference, i.e. beyond mean-field, implementation such that the single-reference, i.e. "mean-field", derives as a particular case. As such, a key point of the presentation provided here is to demonstrate that the multi-reference EDF method can indeed be formulated in a {\\it mathematically} meaningful fashion even if $E[g',g]$ does {\\it not} derive from a genuine Hamilton operator. In particular, the restoration of symmetries can be entirely formulated without making {\\it any} reference to a projected state, i.e. within a genuine EDF framework. However, and as is illustrated in the present document, a mathematically meaningful formulation does not guarantee that the formalism is sound from a {\\it physical} standpoint. The price at which the latter can be enforced as well in the future is eventually alluded to.

T. Duguet

2013-09-02T23:59:59.000Z

16

Constrained Density-Functional Theory--Configuration Interaction  

E-Print Network (OSTI)

In this thesis, I implemented a method for performing electronic structure calculations, "Constrained Density Functional Theory-- Configuration Interaction" (CDFT-CI), which builds upon the computational strengths of Density ...

Kaduk, Benjamin James

2012-01-01T23:59:59.000Z

17

The Materials Project: Combining Density Functional Theory Calculation...  

NLE Websites -- All DOE Office Websites (Extended Search)

The Materials Project The Materials Project: Combining Density Functional Theory Calculations with Supercomputing Centers for New Materials Discovery May 2, 2013 jain2 Anubhav Jain...

18

First-Principles Density Functional Theory Study of Grain Boundary ...  

Science Conference Proceedings (OSTI)

Presentation Title, First-Principles Density Functional Theory Study of Grain ... It was found that both the vacancy formation energy and diffusion activation ...

19

Nuclear Parton Densities and Structure Functions  

E-Print Network (OSTI)

We calculate nuclear parton distribution functions (PDFs), using the constituent quark model. We find the bounded valon distributions in a nuclear to be related to free valon distributions in a nucleon. By using improved bounded valon distributions for a nuclear with atomic number $A$ and the partonic structure functions inside the valon, we can calculate the nuclear structure function in $x$ space. The results for nuclear structure-function ratio $F_2^A/F_2^D$ at some values of $A$ are in good agreement with the experimental data.

S. Atashbar Tehrani; Ali N. Khorramian; A. Mirjalili

2004-10-27T23:59:59.000Z

20

The benchmark of gutzwiller density functional theory in hydrogen systems  

SciTech Connect

We propose an approximate form of the exchange-correlation energy functional for the Gutzwiller density functional theory. It satisfies certain physical constraints in both weak and strong electron correlation limits. We benchmark the Gutzwiller density functional approximation in the hydrogen systems, where the static correlation error is shown to be negligible. The good transferability is demonstrated by applications to the hydrogen molecule and some crystal structures.

Yao, Y.; Wang, Cai-Zhuang; Ho, Kai-Ming

2012-02-23T23:59:59.000Z

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


21

Correlation Testing in Nuclear Density Functional Theory  

E-Print Network (OSTI)

Correlation testing provides a quick method of discriminating amongst potential terms to include in a nuclear mass formula or functional and is a necessary tool for further nuclear mass models; however a firm mathematical foundation of the method has not been previously set forth. Here, the necessary justification for correlation testing is developed and more detail of the motivation behind its use is give. Examples are provided to clarify the method analytically and for computational benchmarking. We provide a quantitative demonstration of the method's performance and short-comings, highlighting also potential issues a user may encounter. In concluding we suggest some possible future developments to improve the limitations of the method.

M. G. Bertolli

2012-08-07T23:59:59.000Z

22

Development of Novel Density Functionals for Thermochemical Kinetics  

E-Print Network (OSTI)

A new density functional theory (DFT) exchange-correlation functional for the exploration of reaction mechanisms is proposed. This new functional, denoted BMK (Boese-Martin for Kinetics), has an accuracy in the 2 kcal/mol range for transition state barriers but, unlike previous attempts at such a functional, this improved accuracy does not come at the expense of equilibrium properties. This makes it a general-purpose functional whose domain of applicability has been extended to transition states, rather than a specialized functional for kinetics. The improvement in BMK rests on the inclusion of the kinetic energy density together with a large value of the exact exchange mixing coefficient. For this functional, the kinetic energy density appears to correct `back' the excess exact exchange mixing for ground-state properties, possibly simulating variable exchange.

Boese, A D; Martin, Jan M. L.

2004-01-01T23:59:59.000Z

23

Nuclear Energy Density Functionals Constrained by Low-Energy QCD  

E-Print Network (OSTI)

A microscopic framework of nuclear energy density functionals is reviewed, which establishes a direct relation between low-energy QCD and nuclear structure, synthesizing effective field theory methods and principles of density functional theory. Guided by two closely related features of QCD in the low-energy limit: a) in-medium changes of vacuum condensates, and b) spontaneous breaking of chiral symmetry; a relativistic energy density functional is developed and applied in studies of ground-state properties of spherical and deformed nuclei.

Vretenar, Dario

2008-01-01T23:59:59.000Z

24

Nuclear Energy Density Functionals Constrained by Low-Energy QCD  

E-Print Network (OSTI)

A microscopic framework of nuclear energy density functionals is reviewed, which establishes a direct relation between low-energy QCD and nuclear structure, synthesizing effective field theory methods and principles of density functional theory. Guided by two closely related features of QCD in the low-energy limit: a) in-medium changes of vacuum condensates, and b) spontaneous breaking of chiral symmetry; a relativistic energy density functional is developed and applied in studies of ground-state properties of spherical and deformed nuclei.

Dario Vretenar

2008-02-06T23:59:59.000Z

25

Density functional theory and optimal transportation with Coulomb cost  

E-Print Network (OSTI)

We present here novel insight into exchange-correlation functionals in density functional theory, based on the viewpoint of optimal transport. We show that in the case of two electrons and in the semiclassical limit, the exact exchange-correlation functional reduces to a very interesting functional of novel form, which depends on an optimal transport map $T$ associated with a given density $\\rho$. Since the above limit is strongly correlated, the limit functional yields insight into electron correlations. We prove the existence and uniqueness of such an optimal map for any number of electrons and each $\\rho$, and determine the map explicitly in the case when $\\rho$ is radially symmetric.

Codina Cotar; Gero Friesecke; Claudia Klüppelberg

2011-04-04T23:59:59.000Z

26

Energy Density Functional for Nuclei and Neutron Stars  

Science Conference Proceedings (OSTI)

Background: Recent observational data on neutron star masses and radii provide stringent constraints on the equation of state of neutron rich matter [ Annu. Rev. Nucl. Part. Sci. 62 485 (2012)]. Purpose: We aim to develop a nuclear energy density functional that can be simultaneously applied to finite nuclei and neutron stars. Methods: We use the self-consistent nuclear density functional theory (DFT) with Skyrme energy density functionals and covariance analysis to assess correlations between observables for finite nuclei and neutron stars. In a first step two energy functionals a high density energy functional giving reasonable neutron properties, and a low density functional fitted to nuclear properties are matched. In a second step, we optimize a new functional using exactly the same protocol as in earlier studies pertaining to nuclei but now including neutron star data. This allows direct comparisons of performance of the new functional relative to the standard one. Results: The new functional TOV-min yields results for nuclear bulk properties (energy, rms radius, diffraction radius, and surface thickness) that are of the same quality as those obtained with the established Skyrme functionals, including SV-min. When comparing SV-min and TOV-min, isoscalar nuclear matter indicators vary slightly while isovector properties are changed considerably. We discuss neutron skins, dipole polarizability, separation energies of the heaviest elements, and proton and neutron drip lines. We confirm a correlation between the neutron skin of 208Pb and the neutron star radius. Conclusions: We demonstrate that standard energy density functionals optimized to nuclear data do not carry information on the expected maximum neutron star mass, and that predictions can only be made within an extremely broad uncertainty band. For atomic nuclei, the new functional TOV-min performs at least as well as the standard nuclear functionals, but it also reproduces expected neutron star data within assumed error bands. This functional is expected to yield more reliable predictions in the region of very neutron rich heavy nuclei.

Erler, J. [UTK/ORNL/German Cancer Research Center-Heidelberg; Horowitz, C. J. [UTK/ORNL/Indiana University; Nazarewicz, Witold [UTK/ORNL/University of Warsaw; Rafalski, M. [UTK/ORNL; Reinhard, P.-G. [Universitat Erlangen, Germany

2013-01-01T23:59:59.000Z

27

Improved association in a classical density functional theory for water  

E-Print Network (OSTI)

We present a modification to our recently published SAFT-based classical density functional theory for water. We have recently developed and tested a functional for the averaged radial distribution function at contact of the hard-sphere fluid that is dramatically more accurate at interfaces than earlier approximations. We now incorporate this improved functional into the association term of our free energy functional for water, improving its description of hydrogen bonding. We examine the effect of this improvement by studying two hard solutes: a hard hydrophobic rod and a hard sphere. The improved functional leads to a moderate change in the density profile and a large decrease in the number of hydrogen bonds broken in the vicinity of the solutes.We present a modification to our recently published SAFT-based classical density functional theory for water. We have recently developed and tested a functional for the averaged radial distribution function at contact of the hard-sphere fluid that is dramatically more accurate at interfaces than earlier approximations. We now incorporate this improved functional into the association term of our free energy functional for water, improving its description of hydrogen bonding. We examine the effect of this improvement by studying two hard solutes: a hard hydrophobic rod and a hard sphere. The improved functional leads to a moderate change in the density profile and a large decrease in the number of hydrogen bonds broken in the vicinity of the solutes.

Eric J. Krebs; Jeff B. Schulte; David Roundy

2013-09-07T23:59:59.000Z

28

Dynamical density functional theory for dense atomic liquids  

E-Print Network (OSTI)

Starting from Newton's equations of motion, we derive a dynamical density functional theory (DDFT) applicable to atomic liquids. The theory has the feature that it requires as input the Helmholtz free energy functional from equilibrium density functional theory. This means that, given a reliable equilibrium free energy functional, the correct equilibrium fluid density profile is guaranteed. We show that when the isothermal compressibility is small, the DDFT generates the correct value for the speed of sound in a dense liquid. We also interpret the theory as a dynamical equation for a coarse grained fluid density and show that the theory can be used (making further approximations) to derive the standard mode coupling theory that is used to describe the glass transition. The present theory should provide a useful starting point for describing the dynamics of inhomogeneous atomic fluids.

A. J. Archer

2006-04-25T23:59:59.000Z

29

Density Functional Theory with Dissipation: Transport through Single Molecules  

SciTech Connect

A huge amount of fundamental research was performed on this grant. Most of it focussed on fundamental issues of electronic structure calculations of transport through single molecules, using density functional theory. Achievements were: (1) First density functional theory with dissipation; (2) Pseudopotential plane wave calculations with master equation; (3) Weak bias limit; (4) Long-chain conductance; and (5) Self-interaction effects in tunneling.

Kieron Burke

2012-04-30T23:59:59.000Z

30

Exact-exchange density functional theory for neutron drops  

Science Conference Proceedings (OSTI)

We compute the ground-state properties of finite systems of neutrons in an external harmonic trap, interacting via the Minnesota potential, using the ''exact-exchange'' form of orbital-dependent density functional theory. We compare our results with Hartree-Fock calculations and find very close agreement. Within the context of the interaction studied, we conclude that this simple orbital-dependent functional brings conventional nuclear density functional theory to the level of Hartree-Fock in an ab initio fashion. Our work is a first step toward higher order ab initio nuclear functionals based on realistic nucleon-nucleon interactions.

Drut, Joaquin E. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545-0001 (United States); Department of Physics, Ohio State University, Columbus, Ohio 43210-1117 (United States); Platter, Lucas [Fundamental Physics, Chalmers University of Technology, SE-41296 Goeteborg (Sweden); Institute for Nuclear Theory, University of Washington, Seattle, Washington 98195 (United States); Department of Physics, Ohio State University, Columbus, Ohio 43210-1117 (United States)

2011-07-15T23:59:59.000Z

31

Nuclear Density Functional Theory and the Equation of State  

E-Print Network (OSTI)

A nuclear density functional can be used to find the binding energy and shell structure of nuclei and the energy gap in superconducting nuclear matter. In this paper, we study the possible application of a nuclear density functional theory to nuclear astrophysics. From energy density functional theory, we can deduce the interaction between nucleons to find a rough estimate of the charge radius of the specific nuclei. Compared to the Finite-Range Thomas Fermi model, we include three-body forces, which might be important at densities several times that of nuclear matter density. We also add the momentum dependent interaction to take into account the effective mass of the nucleons. We study matter in the neutron star crust using the Wigner-Seitz cell method. By constructing the mass-radius relation of neutron stars and investigating lepton-rich nuclear matter in proto-neutron stars, we find that the density functional can be used to construct an equation of state of hot dense matter.

Yeunhwan Lim

2011-04-06T23:59:59.000Z

32

Nuclear Density Functional Theory and the Equation of State  

E-Print Network (OSTI)

A nuclear density functional can be used to find the binding energy and shell structure of nuclei and the energy gap in superconducting nuclear matter. In this paper, we study the possible application of a nuclear density functional theory to nuclear astrophysics. From energy density functional theory, we can deduce the interaction between nucleons to find a rough estimate of the charge radius of the specific nuclei. Compared to the Finite-Range Thomas Fermi model, we include three-body forces, which might be important at densities several times that of nuclear matter density. We also add the momentum dependent interaction to take into account the effective mass of the nucleons. We study matter in the neutron star crust using the Wigner-Seitz cell method. By constructing the mass-radius relation of neutron stars and investigating lepton-rich nuclear matter in proto-neutron stars, we find that the density functional can be used to construct an equation of state of hot dense matter.

Lim, Yeunhwan

2011-01-01T23:59:59.000Z

33

Neutron skin uncertainties of Skyrme energy density functionals  

E-Print Network (OSTI)

Background: Neutron-skin thickness is an excellent indicator of isovector properties of atomic nuclei. As such, it correlates strongly with observables in finite nuclei that depend on neutron-to-proton imbalance and the nuclear symmetry energy that characterizes the equation of state of neutron-rich matter. A rich worldwide experimental program involving studies with rare isotopes, parity violating electron scattering, and astronomical observations is devoted to pinning down the isovector sector of nuclear models. Purpose: We assess the theoretical systematic and statistical uncertainties of neutron-skin thickness and relate them to the equation of state of nuclear matter, and in particular to nuclear symmetry energy parameters. Methods: We use the nuclear superfluid Density Functional Theory with several Skyrme energy density functionals and density dependent pairing. To evaluate statistical errors and their budget, we employ the statistical covariance technique. Results: We find that the errors on neutron skin increase with neutron excess. Statistical errors due to uncertain coupling constants of the density functional are found to be larger than systematic errors, the latter not exceeding 0.06 fm in most neutron-rich nuclei across the nuclear landscape. The single major source of uncertainty is the poorly determined slope L of the symmetry energy that parametrizes its density dependence. Conclusions: To provide essential constraints on the symmetry energy of the nuclear energy density functional, next-generation measurements of neutron skins are required to deliver precision better than 0.06 fm.

M. Kortelainen; J. Erler; W. Nazarewicz; N. Birge; Y. Gao; E. Olsen

2013-07-16T23:59:59.000Z

34

Relativistic Nuclear Energy Density Functionals: adjusting parameters to binding energies  

E-Print Network (OSTI)

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.

T. Niksic; D. Vretenar; P. Ring

2008-09-08T23:59:59.000Z

35

Nonlinear eigenvalue problems in Density Functional Theory calculations  

SciTech Connect

Developed in the 1960's by W. Kohn and coauthors, Density Functional Theory (DFT) is a very popular quantum model for First-Principles simulations in chemistry and material sciences. It allows calculations of systems made of hundreds of atoms. Indeed DFT reduces the 3N-dimensional Schroedinger electronic structure problem to the search for a ground state electronic density in 3D. In practice it leads to the search for N electronic wave functions solutions of an energy minimization problem in 3D, or equivalently the solution of an eigenvalue problem with a non-linear operator.

Fattebert, J

2009-08-28T23:59:59.000Z

36

Subsystem functionals and the missing ingredient of confinement physics in density functionals  

E-Print Network (OSTI)

The subsystem functional scheme is a promising approach recently proposed for constructing exchange-correlation density functionals. In this scheme, the physics in each part of real materials is described by mapping to a ...

Hao, Feng

37

Probability density function method for variable-density pressure-gradient-driven turbulence and mixing  

SciTech Connect

Probability density function (PDF) methods are extended to variable-density pressure-gradient-driven turbulence. We apply the new method to compute the joint PDF of density and velocity in a non-premixed binary mixture of different-density molecularly mixing fluids under gravity. The full time-evolution of the joint PDF is captured in the highly non-equilibrium flow: starting from a quiescent state, transitioning to fully developed turbulence and finally dissipated by molecular diffusion. High-Atwood-number effects (as distinguished from the Boussinesq case) are accounted for: both hydrodynamic turbulence and material mixing are treated at arbitrary density ratios, with the specific volume, mass flux and all their correlations in closed form. An extension of the generalized Langevin model, originally developed for the Lagrangian fluid particle velocity in constant-density shear-driven turbulence, is constructed for variable-density pressure-gradient-driven flows. The persistent small-scale anisotropy, a fundamentally 'non-Kolmogorovian' feature of flows under external acceleration forces, is captured by a tensorial diffusion term based on the external body force. The material mixing model for the fluid density, an active scalar, is developed based on the beta distribution. The beta-PDF is shown to be capable of capturing the mixing asymmetry and that it can accurately represent the density through transition, in fully developed turbulence and in the decay process. The joint model for hydrodynamics and active material mixing yields a time-accurate evolution of the turbulent kinetic energy and Reynolds stress anisotropy without resorting to gradient diffusion hypotheses, and represents the mixing state by the density PDF itself, eliminating the need for dubious mixing measures. Direct numerical simulations of the homogeneous Rayleigh-Taylor instability are used for model validation.

Bakosi, Jozsef [Los Alamos National Laboratory; Ristorcelli, Raymond J [Los Alamos National Laboratory

2010-01-01T23:59:59.000Z

38

Fragment-based Time-dependent Density-functional Theory  

E-Print Network (OSTI)

Using the Runge-Gross theorem that establishes the foundation of Time-dependent Density Functional Theory (TDDFT) we prove that for a given electronic Hamiltonian, choice of initial state, and choice of fragmentation, there is a unique single-particle potential (dubbed time-dependent partition potential) which, when added to each of the pre-selected fragment potentials, forces the fragment densities to evolve in such a way that their sum equals the exact molecular density at all times. This uniqueness theorem suggests new ways of computing time-dependent properties of electronic systems via fragment-TDDFT calculations. We derive a formally exact relationship between the partition potential and the total density, and illustrate our approach on a simple model system for binary fragmentation in a laser field.

Mosquera, Martin A; Wasserman, Adam

2013-01-01T23:59:59.000Z

39

Density Functional Theory for the Photoionization Dynamics of Uracil  

E-Print Network (OSTI)

Photoionization dynamics of the RNA base Uracil is studied in the framework of Density Functional Theory (DFT). The photoionization calculations take advantage of a newly developed parallel version of a multicentric approach to the calculation of the electronic continuum spectrum which uses a set of B-spline radial basis functions and a Kohn-Sham density functional hamiltonian. Both valence and core ionizations are considered. Scattering resonances in selected single-particle ionization channels are classified by the symmetry of the resonant state and the peak energy position in the photoelectron kinetic energy scale; the present results highlight once more the site specificity of core ionization processes. We further suggest that the resonant structures previously characterized in low-energy electron collision experiments are partly shifted below threshold by the photoionization processes. A critical evaluation of the theoretical results providing a guide for future experimental work on similar biosystems.

Toffoli, D; Gianturco, F A; Lucchese, R R

2007-01-01T23:59:59.000Z

40

Multiscale FEM-MD schema  

Science Conference Proceedings (OSTI)

... coupling finite element modeling (FEM) to atomistic Molecular Dynamics (MD) 1 ... for using extremely high (very unrealistic) indentation rates that are ...

2013-06-27T23:59:59.000Z

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


41

SURFACE SYMMETRY ENERGY OF NUCLEAR ENERGY DENSITY FUNCTIONALS  

Science Conference Proceedings (OSTI)

We study the bulk deformation properties of the Skyrme nuclear energy density functionals. Following simple arguments based on the leptodermous expansion and liquid drop model, we apply the nuclear density functional theory to assess the role of the surface symmetry energy in nuclei. To this end, we validate the commonly used functional parametrizations against the data on excitation energies of superdeformed band-heads in Hg and Pb isotopes, and fission isomers in actinide nuclei. After subtracting shell effects, the results of our self-consistent calculations are consistent with macroscopic arguments and indicate that experimental data on strongly deformed configurations in neutron-rich nuclei are essential for optimizing future nuclear energy density functionals. The resulting survey provides a useful benchmark for further theoretical improvements. Unlike in nuclei close to the stability valley, whose macroscopic deformability hangs on the balance of surface and Coulomb terms, the deformability of neutron-rich nuclei strongly depends on the surface-symmetry energy; hence, its proper determination is crucial for the stability of deformed phases of the neutron-rich matter and description of fission rates for r-process nucleosynthesis.

Nikolov, N; Schunck, N; Nazarewicz, W; Bender, M; Pei, J

2010-12-20T23:59:59.000Z

42

Curvature and Frontier Orbital Energies in Density Functional Theory  

SciTech Connect

Perdew et al. [Phys. Rev. Lett 49, 1691 (1982)] discovered and proved two different properties that exact Kohn-Sham density functional theory (DFT) must obey: (i) The exact total energy versus particle number must be a series of linear segments between integer electron points; (ii) Across an integer number of electrons, the exchange-correlation potential may ``jump’’ by a constant, known as the derivative discontinuity (DD). Here, we show analytically that in both the original and the generalized Kohn-Sham formulation of DFT, the two are in fact two sides of the same coin. Absence of a derivative discontinuity necessitates deviation from piecewise linearity, and the latter can be used to correct for the former, thereby restoring the physical meaning of the orbital energies. Using selected small molecules, we show that this results in a simple correction scheme for any underlying functional, including semi-local and hybrid functionals as well as Hartree-Fock theory, suggesting a practical correction for the infamous gap problem of density functional theory. Moreover, we show that optimally-tuned range-separated hybrid functionals can inherently minimize both DD and curvature, thus requiring no correction, and show that this can be used as a sound theoretical basis for novel tuning strategies.

Stein, Tamar; Autschbach, Jochen; Govind, Niranjan; Kronik, Leeor; Baer, Roi

2012-12-20T23:59:59.000Z

43

Probability density function transformation using seeded localized averaging  

SciTech Connect

Seeded Localized Averaging (SLA) is a spectrum acquisition method that averages pulse-heights in dynamic windows. SLA sharpens peaks in the acquired spectra. This work investigates the transformation of the original probability density function (PDF) in the process of applying SLA procedure. We derive an analytical expression for the resulting probability density function after an application of SLA. In addition, we prove the following properties: 1) for symmetric distributions, SLA preserves both the mean and symmetry. 2) for uni-modal symmetric distributions, SLA reduces variance, sharpening the distributions peak. Our results are the first to prove these properties, reinforcing past experimental observations. Specifically, our results imply that in the typical case of a spectral peak with Gaussian PDF the full width at half maximum (FWHM) of the transformed peak becomes narrower even with averaging of only two pulse-heights. While the Gaussian shape is no longer preserved, our results include an analytical expression for the resulting distribution. Examples of the transformation of other PDFs are presented. (authors)

Dimitrov, N. B. [Operations Research Dept., Naval Postgraduate School, Monterey, CA 93943 (United States); Jordanov, V. T. [Yantel, LLC, Santa Fe, NM 87508 (United States)

2011-07-01T23:59:59.000Z

44

Building A Universal Nuclear Energy Density Functional (UNEDF)  

Science Conference Proceedings (OSTI)

During the period of Dec. 1 2006 â?? Jun. 30, 2012, the UNEDF collaboration carried out a comprehensive study of all nuclei, based on the most accurate knowledge of the strong nuclear interaction, the most reliable theoretical approaches, the most advanced algorithms, and extensive computational resources, with a view towards scaling to the petaflop platforms and beyond. The long-term vision initiated with UNEDF is to arrive at a comprehensive, quantitative, and unified description of nuclei and their reactions, grounded in the fundamental interactions between the constituent nucleons. We seek to replace current phenomenological models of nuclear structure and reactions with a well-founded microscopic theory that delivers maximum predictive power with well-quantified uncertainties. Specifically, the mission of this project has been three-fold: first, to find an optimal energy density functional (EDF) using all our knowledge of the nucleonic Hamiltonian and basic nuclear properties; second, to apply the EDF theory and its extensions to validate the functional using all the available relevant nuclear structure and reaction data; third, to apply the validated theory to properties of interest that cannot be measured, in particular the properties needed for reaction theory. The main physics areas of UNEDF, defined at the beginning of the project, were: ab initio structure; ab initio functionals; DFT applications; DFT extensions; reactions.

Carlson, Joe, Los Alamos National Laboratory, Los Alamos, NM; Furnstahl, Dick, Ohio State University, Columbus, OH; Horoi, Mihai, Central Michigan University, Mount Pleasant, MI; Lusk, Rusty, Argonne National Laboratory, Argonne, IL; Nazarewicz, Witek, University of Tennessee, Knoxville, TN; Ng, Esmond, Berkeley National Laboratory, Berkeley, CA; Thompson, Ian, Lawrence Livermore National Laboratory, Livermore, CA; Vary, James, Iowa State University, Ames, Iowa

2012-09-30T23:59:59.000Z

45

A Density Functional Theory Study of Formaldehyde Adsorption on Ceria  

Science Conference Proceedings (OSTI)

Molecular adsorption of formaldehyde on the stoichiometric CeO2(111) and CeO2(110) surfaces was studied using periodic density functional theory. Two adsorption modes (strong chemisorbed and weak physisorbed) were identified on both surfaces. This is consistent with recent experimental observations. On the (111) surface, formaldehyde strongly chemisorbs with an adsorption energy of 0.86 eV to form a dioxymethylene-like structure, in which a surface O lifts from the surface to bind with the C of formaldehyde. A weak physisorbed state with adsorption energy of 0.28 eV was found with the O of formaldehyde interacting with a surface Ce. On the (110) surface, dioxymethyelene formation was also observed, with an adsorption energy of 1.31 eV. The weakly adsorbed state of formaldehyde on the (110) surface was energetically comparable to the weak adsorption state on the (111) surface, but adsorption occurred through a formaldehyde C and surface O interaction. Analysis of the local density of states and charge density differences after adsorption shows that strong covalent bonding occurs between the C of formaldehyde and surface O when dioxymethylene forms. Calculated vibrational frequencies also confirm dioxymethylene formation. Our results also show that as the coverage increases, the adsorption of formaldehyde on the (111) surface becomes weak, but is nearly unaffected on the (110) surface. This work was supported by a Laboratory Directed Research and Development (LDRD) project of the Pacific Northwest National Laboratory (PNNL). The computations were performed using the Molecular Science Computing Facility in the William R. Wiley Environmental Molecular Sciences Laboratory, which is a U.S. Department of Energy national scientific user facility located at PNNL in Richland, Washington. Computing time was made under a Computational Grand Challenge “Computational Catalysis”. Part of the computing time was also granted by the National Energy Research Scientific Computing Center (NERSC).

Mei, Donghai; Deskins, N. Aaron; Dupuis, Michel

2007-11-01T23:59:59.000Z

46

Density Functional Studies of Methanol Decomposition on Subnanometer Pd Clusters  

DOE Green Energy (OSTI)

A density functional theory study of the decomposition of methanol on subnanometer palladium clusters (primarily Pd4) is presented. Methanol dehydrogenation through C-H bond breaking to form hydroxymethyl (CH2OH) as the initial step, followed by steps involving formation of hydroxymethylene (CHOH), formyl (CHO), and carbon monoxide (CO), is found to be the most favorable reaction pathway. A competing dehydrogenation pathway with O-H bond breaking as the first step, followed by formation of methoxy (CH3O) and formaldehyde (CH2O), is slightly less favorable. In contrast, pathways involving C-O bond cleavage are much less energetically favorable, and no feasible pathways involving C-O bond formation to yield dimethyl ether (CH3OCH3) are found. Comparisons of the results are made with methanol decomposition products adsorbed on more extended Pd surfaces; all reaction intermediates are found to bind slightly more strongly to the clusters than to the surfaces.

Mehmood, Faisal; Greeley, Jeffrey P.; Curtiss, Larry A.

2009-12-31T23:59:59.000Z

47

An Isofactorial Change-of-Scale Model for the Wind Speed Probability Density Function  

Science Conference Proceedings (OSTI)

The wind speed probability density function (PDF) is used in a variety of applications in meteorology, oceanography, and climatology usually as a dataset comparison tool of a function of a quantity such as momentum flux or wind power density. The ...

Mark L. Morrissey; Angie Albers; J. Scott Greene; Susan Postawko

2010-02-01T23:59:59.000Z

48

Category:Baltimore, MD | Open Energy Information  

Open Energy Info (EERE)

MD MD Jump to: navigation, search Go Back to PV Economics By Location Media in category "Baltimore, MD" The following 16 files are in this category, out of 16 total. SVFullServiceRestaurant Baltimore MD Baltimore Gas & Electric Co.png SVFullServiceRestauran... 69 KB SVQuickServiceRestaurant Baltimore MD Baltimore Gas & Electric Co.png SVQuickServiceRestaura... 67 KB SVHospital Baltimore MD Baltimore Gas & Electric Co.png SVHospital Baltimore M... 69 KB SVLargeHotel Baltimore MD Baltimore Gas & Electric Co.png SVLargeHotel Baltimore... 69 KB SVLargeOffice Baltimore MD Baltimore Gas & Electric Co.png SVLargeOffice Baltimor... 69 KB SVMediumOffice Baltimore MD Baltimore Gas & Electric Co.png SVMediumOffice Baltimo... 68 KB SVMidriseApartment Baltimore MD Baltimore Gas & Electric Co.png

49

Hybrid Dynamic Density Functional Theory for Polymer Melts and Blends  

E-Print Network (OSTI)

We propose a high-speed and accurate hybrid dynamic density functional theory for the computer simulations of the phase separation processes of polymer melts and blends. The proposed theory is a combination of the dynamic self-consistent field (SCF) theory and a time-dependent Ginzburg-Landau type theory with the random phase approximation (GRPA). The SCF theory is known to be accurate in evaluating the free energy of the polymer systems in both weak and strong segregation regions although it has a disadvantage of the requirement of a considerable amount of computational cost. On the other hand, the GRPA theory has an advantage of much smaller amount of required computational cost than the SCF theory while its applicability is limited to the weak segregation region. To make the accuracy of the SCF theory and the high-performance of the GRPA theory compatible, we adjust the chemical potential of the GRPA theory by using the SCF theory every constant time steps in the dynamic simulations. The performance of the GRPA and the hybrid theories is tested by using several systems composed of an A/B homopolymer, an AB diblock copolymer, or an ABC triblock copolymer. Using the hybrid theory, we succeeded in reproducing the metastable complex phase-separated domain structures of an ABC triblock copolymer observed by experiments.

Takashi Honda; Toshihiro Kawakatsu

2006-09-05T23:59:59.000Z

50

Subspace accelerated inexact Newton method for large scale wave functions calculations in Density Functional Theory  

SciTech Connect

We describe an iterative algorithm to solve electronic structure problems in Density Functional Theory. The approach is presented as a Subspace Accelerated Inexact Newton (SAIN) solver for the non-linear Kohn-Sham equations. It is related to a class of iterative algorithms known as RMM-DIIS in the electronic structure community. The method is illustrated with examples of real applications using a finite difference discretization and multigrid preconditioning.

Fattebert, J

2008-07-29T23:59:59.000Z

51

Optimized local basis set for Kohn-Sham density functional theory  

Science Conference Proceedings (OSTI)

We develop a technique for generating a set of optimized local basis functions to solve models in the Kohn-Sham density functional theory for both insulating and metallic systems. The optimized local basis functions are obtained by solving a minimization ... Keywords: Discontinuous Galerkin, Electronic structure, GMRES, Kohn-Sham density functional theory, Molecular dynamics, Optimized local basis set, Preconditioning, Pulay force, Trace minimization

Lin Lin; Jianfeng Lu; Lexing Ying; Weinan E

2012-05-01T23:59:59.000Z

52

Microscopically-based energy density functionals for nuclei using the density matrix expansion: Implementation and pre-optimization  

E-Print Network (OSTI)

In a recent series of papers, Gebremariam, Bogner, and Duguet derived a microscopically based nuclear energy density functional by applying the Density Matrix Expansion (DME) to the Hartree-Fock energy obtained from chiral effective field theory (EFT) two- and three-nucleon interactions. Due to the structure of the chiral interactions, each coupling in the DME functional is given as the sum of a coupling constant arising from zero-range contact interactions and a coupling function of the density arising from the finite-range pion exchanges. Since the contact contributions have essentially the same structure as those entering empirical Skyrme functionals, a microscopically guided Skyrme phenomenology has been suggested in which the contact terms in the DME functional are released for optimization to finite-density observables to capture short-range correlation energy contributions from beyond Hartree-Fock. The present paper is the first attempt to assess the ability of the newly suggested DME functional, which has a much richer set of density dependencies than traditional Skyrme functionals, to generate sensible and stable results for nuclear applications. The results of the first proof-of-principle calculations are given, and numerous practical issues related to the implementation of the new functional in existing Skyrme codes are discussed. Using a restricted singular value decomposition (SVD) optimization procedure, it is found that the new DME functional gives numerically stable results and exhibits a small but systematic reduction of our test $\\chi^2$ function compared to standard Skyrme functionals, thus justifying its suitability for future global optimizations and large-scale calculations.

M. Stoitsov; M. Kortelainen; S. K. Bogner; T. Duguet; R. J. Furnstahl; B. Gebremariam; N. Schunck

2010-09-17T23:59:59.000Z

53

An Improved Method for Estimating the Wind Power Density Distribution Function  

Science Conference Proceedings (OSTI)

The wind power density (WPD) distribution curve is essential for wind power assessment and wind turbine engineering. The usual practice of estimating this curve from wind speed data is to first estimate the wind speed probability density function ...

Mark L. Morrissey; Werner E. Cook; J. Scott Greene

2010-07-01T23:59:59.000Z

54

Density Functional Theory Calculations of Mass Transport in UO2  

SciTech Connect

In this talk we present results of density functional theory (DFT) calculations of U, O and fission gas diffusion in UO{sub 2}. These processes all impact nuclear fuel performance. For example, the formation and retention of fission gas bubbles induce fuel swelling, which leads to mechanical interaction with the clad thereby increasing the probability for clad breach. Alternatively, fission gas can be released from the fuel to the plenum, which increases the pressure on the clad walls and decreases the gap thermal conductivity. The evolution of fuel microstructure features is strongly coupled to diffusion of U vacancies. Since both U and fission gas transport rates vary strongly with the O stoichiometry, it is also important to understand O diffusion. In order to better understand bulk Xe behavior in UO{sub 2{+-}x} we first calculate the relevant activation energies using DFT techniques. By analyzing a combination of Xe solution thermodynamics, migration barriers and the interaction of dissolved Xe atoms with U, we demonstrate that Xe diffusion predominantly occurs via a vacancy-mediated mechanism. Since Xe transport is closely related to diffusion of U vacancies, we have also studied the activation energy for this process. In order to explain the low value of 2.4 eV found for U migration from independent damage experiments (not thermal equilibrium) the presence of vacancy clusters must be included in the analysis. Next we investigate species transport on the (111) UO{sub 2} surface, which is motivated by the formation of small voids partially filled with fission gas atoms (bubbles) in UO{sub 2} under irradiation. Surface diffusion could be the rate-limiting step for diffusion of such bubbles, which is an alternative mechanism for mass transport in these materials. As expected, the activation energy for surface diffusion is significantly lower than for bulk transport. These results are further discussed in terms of engineering-scale fission gas release models. Finally, oxidation of UO{sub 2} and the importance of cluster formation for understanding thermodynamic and kinetic properties of UO{sub 2+x} are investigated.

Andersson, Anders D. [Los Alamos National Laboratory; Dorado, Boris [CEA; Uberuaga, Blas P. [Los Alamos National Laboratory; Stanek, Christopher R. [Los Alamos National Laboratory

2012-06-26T23:59:59.000Z

55

Tractable Analytic Expressions for the Wind Speed Probability Density Functions Using Expansions of Orthogonal Polynomials  

Science Conference Proceedings (OSTI)

The use of the two-parameter Weibull function as an estimator of the wind speed probability density function (PDF) is known to be problematic when a high accuracy of fit is required, such as in the computation of the wind power density function. ...

Mark L. Morrissey; J. Scott Greene

2012-07-01T23:59:59.000Z

56

Stretched hydrogen molecule from a constrained-search density-functional perspective  

SciTech Connect

Constrained-search density functional theory gives valuable insights into the fundamentals of density functional theory. It provides exact results and bounds on the ground- and excited-state density functionals. An important advantage of the theory is that it gives guidance in the construction of functionals. Here they engage constrained search theory to explore issues associated with the functional behavior of 'stretched bonds' in molecular hydrogen. A constrained search is performed with familiar valence bond wavefunctions ordinarily used to describe molecular hydrogen. The effective, one-electron hamiltonian is computed and compared to the corresponding uncorrelated, Hartree-Fock effective hamiltonian. Analysis of the functional suggests the need to construct different functionals for the same density and to allow a competition among these functions. As a result the correlation energy functional is composed explicitly of energy gaps from the different functionals.

Valone, Steven M [Los Alamos National Laboratory; Levy, Mel [DIKE UNIV.

2009-01-01T23:59:59.000Z

57

On the breaking and restoration of symmetries within the nuclear energy density functional formalism  

E-Print Network (OSTI)

We review the notion of symmetry breaking and restoration within the frame of nuclear energy density functional methods. We focus on key differences between wave-function- and energy-functional-based methods. In particular, we point to difficulties encountered within the energy functional framework and discuss new potential constraints on the underlying energy density functional that could make the restoration of broken symmetries better formulated within such a formalism. We refer to Ref.~\\cite{duguet10a} for details.

T. Duguet; J. Sadoudi

2010-10-19T23:59:59.000Z

58

A functional density-based nonparametric approach for statistical calibration  

Science Conference Proceedings (OSTI)

In this paper a new nonparametric functional method is introduced for predicting a scalar random variable Y from a functional random variable X. The resulting prediction has the form of a weighted average of the training data set, where ...

Noslen Hernández; Rolando J. Biscay; Nathalie Villa-Vialaneix; Isneri Talavera

2010-11-01T23:59:59.000Z

59

Density Functional Theory Study of Copper Oxide as Low-cost ...  

Science Conference Proceedings (OSTI)

Density Functional Theory Study of Copper Oxide as Low-cost Photovoltaic Material · Dye-sensitized Solar Cells with Anodized Aluminum Alloy-based Counter- ...

60

DENSITY  

Science Conference Proceedings (OSTI)

... Table 2: Principal mineral phases found in the granite rock. Mineral phase. ... Table 4. Average density of 12 granite rocks by Archimedes and CT. ...

2007-01-08T23:59:59.000Z

Note: This page contains sample records for the topic "md density functional" from the National Library of EnergyBeta (NLEBeta).
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We encourage you to perform a real-time search of NLEBeta
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61

Empirical Proton-Neutron Interactions and Nuclear Density Functional Theory: Global, Regional and Local Comparisons  

E-Print Network (OSTI)

Calculations of nuclear masses, using nuclear density functional theory, are presented for even-even nuclei spanning the nuclear chart. The resulting binding energy differences can be interpreted in terms of valence proton-neutron interactions. These are compared globally, regionally, and locally with empirical values. Overall, excellent agreement is obtained. Discrepancies highlight neglected degrees of freedom and can point to improved density functionals.

Stoitsov, M; Casten, R F; Nazarewicz, W; Satula, W

2006-01-01T23:59:59.000Z

62

Empirical Proton-Neutron Interactions and Nuclear Density Functional Theory: Global, Regional, and Local Comparisons  

Science Conference Proceedings (OSTI)

Calculations of nuclear masses, using nuclear density functional theory, are presented for even-even nuclei spanning the nuclear chart. The resulting binding energy differences can be interpreted in terms of valence proton-neutron interactions. These are compared globally, regionally, and locally with empirical values. Overall, excellent agreement is obtained. Discrepancies highlight neglected degrees of freedom and can point to improved density functionals.

Stoitsov, Mario [ORNL; Cakirli, R. B. [Yale University; Casten, R. F. [Yale University; Nazarewicz, Witold [ORNL; Satula, W. [Warsaw University

2007-01-01T23:59:59.000Z

63

Empirical Proton-Neutron Interactions and Nuclear Density Functional Theory: Global, Regional and Local Comparisons  

E-Print Network (OSTI)

Calculations of nuclear masses, using nuclear density functional theory, are presented for even-even nuclei spanning the nuclear chart. The resulting binding energy differences can be interpreted in terms of valence proton-neutron interactions. These are compared globally, regionally, and locally with empirical values. Overall, excellent agreement is obtained. Discrepancies highlight neglected degrees of freedom and can point to improved density functionals.

M. Stoitsov; R. B. Cakirli; R. F. Casten; W. Nazarewicz; W. Satula

2006-11-14T23:59:59.000Z

64

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

Science Conference Proceedings (OSTI)

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 ... Keywords: Density functional theory, Electronic structure, First-principles, GPU, Molecular dynamics, Plane wave pseudopotential

Weile Jia, Jiyun Fu, Zongyan Cao, Long Wang, Xuebin Chi, Weiguo Gao, Lin-Wang Wang

2013-10-01T23:59:59.000Z

65

Free energies, vacancy concentrations and density distribution anisotropies in hard--sphere crystals: A combined density functional and simulation study  

E-Print Network (OSTI)

We perform a comparative study of the free energies and the density distributions in hard sphere crystals using Monte Carlo simulations and density functional theory (employing Fundamental Measure functionals). Using a recently introduced technique (Schilling and Schmid, J. Chem. Phys 131, 231102 (2009)) we obtain crystal free energies to a high precision. The free energies from Fundamental Measure theory are in good agreement with the simulation results and demonstrate the applicability of these functionals to the treatment of other problems involving crystallization. The agreement between FMT and simulations on the level of the free energies is also reflected in the density distributions around single lattice sites. Overall, the peak widths and anisotropy signs for different lattice directions agree, however, it is found that Fundamental Measure theory gives slightly narrower peaks with more anisotropy than seen in the simulations. Among the three types of Fundamental Measure functionals studied, only the White Bear II functional (Hansen-Goos and Roth, J. Phys.: Condens. Matter 18, 8413 (2006)) exhibits sensible results for the equilibrium vacancy concentration and a physical behavior of the chemical potential in crystals constrained by a fixed vacancy concentration.

M. Oettel; S. Goerig; A. Haertel; H. Loewen; M. Radu; T. Schilling

2010-09-03T23:59:59.000Z

66

Applications of Skyrme energy-density functional to fusion reactions spanning the fusion barriers  

E-Print Network (OSTI)

The Skyrme energy density functional has been applied to the study of heavy-ion fusion reactions. The barriers for fusion reactions are calculated by the Skyrme energy density functional with proton and neutron density distributions determined by using restricted density variational (RDV) method within the same energy density functional together with semi-classical approach known as the extended semi-classical Thomas-Fermi method. Based on the fusion barrier obtained, we propose a parametrization of the empirical barrier distribution to take into account the multi-dimensional character of real barrier and then apply it to calculate the fusion excitation functions in terms of barrier penetration concept. A large number of measured fusion excitation functions spanning the fusion barriers can be reproduced well. The competition between suppression and enhancement effects on sub-barrier fusion caused by neutron-shell-closure and excess neutron effects is studied.

Min Liu; Ning Wang; Zhuxia Li; Xizhen Wu; Enguang Zhao

2005-09-26T23:59:59.000Z

67

Antisymmetrized Green's function approach to $(e,e')$ reactions with a realistic nuclear density  

E-Print Network (OSTI)

A completely antisymmetrized Green's function approach to the inclusive quasielastic $(e,e')$ scattering, including a realistic one-body density, is presented. The single particle Green's function is expanded in terms of the eigenfunctions of the nonhermitian optical potential. This allows one to treat final state interactions consistently in the inclusive and in the exclusive reactions. Nuclear correlations are included in the one-body density. Numerical results for the response functions of $^{16}$O and $^{40}$Ca are presented and discussed.

F. Capuzzi; C. Giusti; F. D. Pacati; D. N. Kadrev

2004-10-26T23:59:59.000Z

68

Recent developments in classical density functional theory: Internal energy functional and diagrammatic structure of fundamental measure theory  

E-Print Network (OSTI)

An overview of several recent developments in density functional theory for classical inhomogeneous liquids is given. We show how Levy's constrained search method can be used to derive the variational principle that underlies density functional theory. An advantage of the method is that the Helmholtz free energy as a functional of a trial one-body density is given as an explicit expression, without reference to an external potential as is the case in the standard Mermin-Evans proof by reductio ad absurdum. We show how to generalize the approach in order to express the internal energy as a functional of the one-body density distribution and of the local entropy distribution. Here the local chemical potential and the bulk temperature play the role of Lagrange multipliers in the Euler-Lagrange equations for minimiziation of the functional. As an explicit approximation for the free-energy functional for hard sphere mixtures, the diagrammatic structure of Rosenfeld's fundamental measure density unctional is laid out. Recent extensions, based on the Kierlik-Rosinberg scalar weight functions, to binary and ternary non-additive hard sphere mixtures are described.

M. Schmidt; M. Burgis; W. S. B. Dwandaru; G. Leithall; P. Hopkins

2012-12-27T23:59:59.000Z

69

Effective 3-Body Interaction for Mean-Field and Density-Functional Theory  

Science Conference Proceedings (OSTI)

Density functionals for nuclei usually include an effective 3-body interaction that depends on a fractional power of the density. Using insights from the many-body theory of the low-density two-component Fermi gas, we consider a new, nonlocal, form for the energy functional that is consistent with the Fock-space representation of interaction operators. In particular, there is a unique spatially nonlocal generalization of the contact form of the interaction that preserves the {rho}{sup 7/3} density dependence required by the many-body theory. We calculate the ground-state energies for particles in a harmonic trap by using the nonlocal induced 3-body interaction and compare them to numerically accurate Green's function Monte Carlo calculations. Using no free parameters, we find that a nonlocality in the space domain provides a better description of the weak-coupling regime than the local-density approximation.

Gezerlis, Alexandros [Department of Physics, University of Washington, Seattle, Washington 98195-1560 (United States); Bertsch, G. F. [Department of Physics, University of Washington, Seattle, Washington 98195-1560 (United States); Institute for Nuclear Theory, University of Washington, Seattle, Washington 98195-1560 (United States)

2010-11-19T23:59:59.000Z

70

Towards a Microscopic Reaction Description Based on Energy Density Functionals  

SciTech Connect

A microscopic calculation of reaction cross sections for nucleon-nucleus scattering has been performed by explicitly coupling the elastic channel to all particle-hole excitations in the target and one-nucleon pickup channels. The particle-hole states may be regarded as doorway states through which the flux flows to more complicated configurations, and subsequently to long-lived compound nucleus resonances. Target excitations for {sup 40,48}Ca, {sup 58}Ni, {sup 90}Zr and {sup 144}Sm were described in a random-phase framework using a Skyrme functional. Reaction cross sections obtained agree very well with experimental data and predictions of a state-of-the-art fitted optical potential. Couplings between inelastic states were found to be negligible, while the pickup channels contribute significantly. The effect of resonances from higher-order channels was assessed. Elastic angular distributions were also calculated within the same method, achieving good agreement with experimental data. For the first time observed absorptions are completely accounted for by explicit channel coupling, for incident energies between 10 and 70 MeV, with consistent angular distribution results.

Nobre, G A; DIetrich, F S; Escher, J E; Thompson, I J; Dupuis, M; Terasaki, J; Engel, J

2011-09-26T23:59:59.000Z

71

Nuclear Physics A 770 (2006) 131 Relativistic nuclear energy density functional  

E-Print Network (OSTI)

Nuclear Physics A 770 (2006) 1­31 Relativistic nuclear energy density functional constrained by low 10 February 2006 Available online 3 March 2006 Abstract A relativistic nuclear energy density of Sn and Pb nuclei are studied as test cases for the isospin dependence of the underlying interactions

Weise, Wolfram

72

Charge transport, configuration interaction and Rydberg states under density functional theory  

E-Print Network (OSTI)

Density functional theory (DFT) is a computationally efficient formalism for studying electronic structure and dynamics. In this work, we develop DFT-based excited-state methods to study electron transport, Rydberg excited ...

Cheng, Chiao-Lun

2008-01-01T23:59:59.000Z

73

Shape control of conditional output probability density functions for linear stochastic systems with random parameters  

Science Conference Proceedings (OSTI)

This paper presents a controller design for shaping conditional output probability density functions (pdf) for non-Gaussian dynamic stochastic systems whose coefficients are random and represented by their known pdfs. The moment-generating ...

Aiping Wang; Yongji Wang; Hong Wang

2011-03-01T23:59:59.000Z

74

Density functional theory study of the conductivity of the biphenalenyl radical dimer  

E-Print Network (OSTI)

We present ab initio molecular calculations at different levels of density functional theory (DFT) for the spiro-biphenalenyl neurtral radical in its singlet and triplet states. We performed calculations on the dimer to ...

Lu, Aiyan

2007-01-01T23:59:59.000Z

75

Small-Scale and Mesoscale Variability in Cloudy Boundary Layers: Joint Probability Density Functions  

Science Conference Proceedings (OSTI)

The joint probability density function (PDF) of vertical velocity and conserved scalars is important for at least two reasons. First, the shape of the joint PDF determines the buoyancy flux in partly cloudy layers. Second, the PDF provides a ...

Vincent E. Larson; Jean-Christophe Golaz; William R. Cotton

2002-12-01T23:59:59.000Z

76

Using Probability Density Functions to Derive Consistent Closure Relationships among Higher-Order Moments  

Science Conference Proceedings (OSTI)

Parameterizations of turbulence often predict several lower-order moments and make closure assumptions for higher-order moments. In principle, the low- and high-order moments share the same probability density function (PDF). One closure ...

Vincent E. Larson; Jean-Christophe Golaz

2005-04-01T23:59:59.000Z

77

Non-Gaussian Velocity Probability Density Functions: An Altimetric Perspective of the Mediterranean Sea  

Science Conference Proceedings (OSTI)

Velocity probability density functions (PDFs) are a key tool to study complex flows and are of great importance to model particle dispersion. The PDFs of geostrophic velocities derived from sea level anomalies maps for the Mediterranean Sea have ...

Jordi Isern-Fontanet; Emilio García-Ladona; Jordi Font; Antonio García-Olivares

2006-11-01T23:59:59.000Z

78

The Materials genome : rapid materials screening for renewable energy using high-throughput density functional theory  

E-Print Network (OSTI)

This thesis relates to the emerging field of high-throughput density functional theory (DFT) computation for materials design and optimization. Although highthroughput DFT is a promising new method for materials discovery, ...

Jain, Anubhav, Ph.D. Massachusetts Institute of Technology

2011-01-01T23:59:59.000Z

79

Fission of actinides and superheavy nuclei: covariant density functional theory perspective  

E-Print Network (OSTI)

The current status of the application of covariant density functional theory to the description of fission barriers in actinides and superheavy nuclei is reviewed. The achievements and open problems are discussed.

A. V. Afanasjev

2013-03-05T23:59:59.000Z

80

Covariant Density Functional Theory--highlights on recent progress and applications  

SciTech Connect

The density functional theory with a few number of parameters allows a very successful phenomenological description of ground state properties of nuclei all over the nuclear chart. The recent progress on the application of the covariant density functional theory (CDFT) for nuclear structure and astrophysics as well as its extensions by the group in Beijing is summarized. In particular, its application to magnetic moments is discussed in details.

Meng, J. [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191 (China); Li, J.; Zhao, P. W.; Liang, H. Z. [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Yao, J. M. [School of Physical Science and Technology, Southwest University, Chongqing 400715 (China)

2011-05-06T23:59:59.000Z

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


81

Colle-Salvetti-type local density functional for the exchange-correlation energy in two dimensions  

Science Conference Proceedings (OSTI)

We derive an approximate local density functional for the exchange-correlation energy to be used in density-functional calculations of two-dimensional systems. In the derivation we employ the Colle-Salvetti wave function within the scheme of Salvetti and Montagnani [Phys. Rev. A 63, 052109 (2001)] to satisfy the sum rule for the exchange-correlation hole. We apply the functional to the two-dimensional homogeneous electron gas as well as to a set of quantum dots and find a very good agreement with exact reference data.

Sakiroglu, S. [Nanoscience Center, Department of Physics, University of Jyvaeskylae, P. O. Box 35, FI-40014 Jyvaeskylae (Finland); Physics Department, Faculty of Arts and Sciences, Dokuz Eyluel University, 35160 Izmir (Turkey); Raesaenen, E. [Nanoscience Center, Department of Physics, University of Jyvaeskylae, P. O. Box 35, FI-40014 Jyvaeskylae (Finland)

2010-07-15T23:59:59.000Z

82

Harvesting graphics power for MD simulations  

E-Print Network (OSTI)

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/$.

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

2007-09-20T23:59:59.000Z

83

N-density representability and the optimal transport limit of the Hohenberg-Kohn functional  

E-Print Network (OSTI)

We derive and analyze a hierarchy of approximations to the strongly correlated limit of the Hohenberg-Kohn functional. These "density representability approximations" are obtained by first noting that in the strongly correlated limit, N-representability of the pair density reduces to the requirement that the pair density must come from a symmetric N-point density. One then relaxes this requirement to the existence of a representing symmetric k-point density with k < N. The approximate energy can be computed by simulating a fictitious k-electron system. We investigate the approximations by deriving analytically exact results for a 2-site model problem, and by incorporating them into a self-consistent Kohn-Sham calculation for small atoms. We find that the low order representability conditions already capture the main part of the correlations.

Friesecke, Gero; Pass, Brendan; Cotar, Codina; Klüppelberg, Claudia

2013-01-01T23:59:59.000Z

84

An exchange functional that tests the robustness of the plasmon description of the van der Waals density functional  

E-Print Network (OSTI)

Is the plasmon description within the non-local correlation of the van der Waals density functional by Dion and coworkers (vdW-DF1) robust enough to describe all exchange-correlation components? To address this question, we design an exchange functional, termed LV-PW86r based on this plasmon description as well as recent analysis on exchange in the large $s$-regime. In the regime with reduced gradients $s=|\

Kristian Berland; Per Hyldgaard

2013-09-06T23:59:59.000Z

85

Nuclear energy density functional from chiral two- and three-nucleon interactions  

E-Print Network (OSTI)

An improved density-matrix expansion is used to calculate the nuclear energy density functional from chiral two- and three-nucleon interactions. The two-body interaction comprises long-range one- and two-pion exchange contributions and a set of contact terms contributing up to fourth power in momenta. In addition we employ the leading order chiral three-nucleon interaction with its parameters $c_E, c_D$ and $c_{1,3,4}$ fixed in calculations of nuclear few-body systems. With this input the nuclear energy density functional is derived to first order in the two- and three-nucleon interaction. We find that the strength functions $F_\

J. W. Holt; N. Kaiser; W. Weise

2011-07-29T23:59:59.000Z

86

Ab initio and density functional studies of hydrocarbon adsorption in zeolites.  

SciTech Connect

The adsorption energies of methane and ethane in zeolites are investigated with ab initio molecular orbital theory and density functional theory. In this work we have used zeolite cluster models containing two, three, and five tetrahedral (Si, Al) atoms and have found equilibrium structures for complexes of methane, ethane, and propane with an acid site. If a large enough cluster is used and correlation effects are included via perturbation theory, the calculated adsorption energy for ethane is about 5 kcal/mol compared with the experimental value of 7.5 kcal/mol. The B3LYP density functional method gives a much smaller binding of {approximately}1 kcal/mol for ethane. The reason for the failure of density fictional theory is unclear.

Curtiss, L. A.

1998-08-21T23:59:59.000Z

87

Perspective: Advances and challenges in treating van der Waals dispersion forces in density functional theory  

E-Print Network (OSTI)

of the previous noble gas and group III atom. Fur- thermore, the dispersion energy, Edisp, is scaled according range dispersion interaction with the underlying exchange or XC functionals. A. Gas phase clustersPerspective: Advances and challenges in treating van der Waals dispersion forces in density

Alavi, Ali

88

Calculations of free energies in liquid and solid phases: Fundamental measure density-functional approach  

E-Print Network (OSTI)

Calculations of free energies in liquid and solid phases: Fundamental measure density, a theoretical description of the free energies and correlation functions of hard-sphere (HS) liquid and solid-Chandler-Andersen perturbation theory, free energies of liquid and solid phases with many interaction potentials can be obtained

Song, Xueyu

89

The Probability Density Function of Ocean Surface Slopes and Its Effects on Radar Backscatter  

Science Conference Proceedings (OSTI)

Based on Longuet-Higgins’s theory of the probability distribution of wave amplitude and wave period and on some observations, a new probability density function (PDF) of ocean surface slopes is derived. It is where ?x and ?y are the slope ...

Y. Liu; X-H. Yan; W. T. Liu; P. A. Hwang

1997-05-01T23:59:59.000Z

90

Energy density functional analysis of shape coexistence in {sup 44}S  

SciTech Connect

The structure of low-energy collective states in the neutron-rich nucleus {sup 44}S is analyzed using a microscopic collective Hamiltonian model based on energy density functionals (EDFs). The calculated triaxial energy map, low-energy spectrum and corresponding probability distributions indicate a coexistence of prolate and oblate shapes in this nucleus.

Li, Z. P.; Yao, J. M.; Vretenar, D.; Niksic, T.; Meng, J. [School of Physical Science and Technology, Southwest University, Chongqing 400715 (China); Physics Department, Faculty of Science, University of Zagreb (Croatia); State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China)

2012-10-20T23:59:59.000Z

91

Prediction of [superscript 57] Fe Mossbauer Parameters by Density Functional Theory: A Benchmark Study  

E-Print Network (OSTI)

We report the performance of eight density functionals (B3LYP, BPW91, OLYP, O3LYP, M06, M06-2X, PBE, and SVWN5) in two Gaussian basis sets (Wachters and Partridge-1 on iron atoms; cc-pVDZ on the rest of atoms) for prediction ...

Bochevarov, Arteum D.

92

Spontaneous fission of /sup 259/Md  

SciTech Connect

The mass and kinetic energy distributions of fission fragments from the spontaneous fission of th newly discovered nuclide /sup 259/Md were obtained. /sup 259/Md was identified as the E. C. daughter of /sup 259/No, and was found to decay entirely (> 95%) by spontaneous fission with a 95-min half-life. From the kinetic energies measured for 397 pairs of coincident fragments, a mass distribution was derived that is symmetric with sigma = 13 amu. /sup 259/Md, together with /sup 258/Fm and /sup 259/Fm, form a select group of three nuclides whose mass division in spontaneous fission is highly symmetric. Unlike the total-kinetic-energy (TKE) distributions of /sup 258/Fm and /sup 259/Fm, which peak at approx. = to 240 MeV, this distribution for /sup 259/Md is broad and is 50 MeV lower in energy. Analysis of the mass and energy distributions shows that events near mass symmetry also exhibit a broad TKE distribution, with one-third of the symmetric events having TKEs less than 200 MeV. The associated of low TKEs with symmetric mass division in the fission of very heavy actinides is anomalous and inconsistent with theories based upon the emergence of fragment shells near the scission point. Either three-body fragmentation or peculiar fragment shapes are assumed as the cause for the large consumption of Coulomb energy observed for a significant fraction of symmetric fissions in /sup 259/Md. 6 figures.

Hulet, E.K.; Wild, J.F.; Lougheed, R.W.; Baisden, P.A.; Landrum, J.H.; Dougan, R.J.; Mustafa, M.; Ghiorso, A.; Nitschke, J.M.

1979-05-04T23:59:59.000Z

93

Weak Bonds from a Semilocal Density Functional with the Right Ingredients  

E-Print Network (OSTI)

Computationally-efficient semilocal approximations of density functional theory at the level of the local spin density approximation (LSDA) or generalized gradient approximation (GGA) poorly describe weak interactions. We show improved descriptions for weak bonds (without loss of accuracy for strong ones) from a newly-developed semilocal meta-GGA (MGGA), by applying it to: 1) the binding energy curve of graphene adsorbed on a Ni (111) surface, where both chemi- and physisorption minima are present; 2) stacking of DNA/RNA nucleobases. We argue that this improvement comes from using the right MGGA dimensionless ingredient to recognize all degrees of orbital overlap.

Sun, Jianwei; Fang, Yuan; Haunschild, Robin; Hao, Pan; Ruzsinszky, Adrienn; Csonka, Gabor I; Scuseria, Gustavo E; Perdew, John P

2013-01-01T23:59:59.000Z

94

The ESO Slice Project (ESP) galaxy redshift survey: II. The luminosity function and mean galaxy density  

E-Print Network (OSTI)

(Abridged) The ESO Slice Project (ESP) is a galaxy redshift survey we have completed as an ESO Key-Project over ~23 square degrees, in a region near the South Galactic Pole. The survey is nearly complete to the limiting magnitude b_J=19.4 and consists of 3342 galaxies with reliable redshift determination. The ESP survey is intermediate between shallow, wide angle samples and very deep, one-dimensional pencil beams: spanning a volume of ~ 5 x 10^4 Mpc^3 at the sensitivity peak (z ~ 0.1), it provides an accurate determination of the "local" luminosity function and the mean galaxy density. We find that, although a Schechter function is an acceptable representation of the luminosity function over the entire range of magnitudes (M -17. The amplitude and the alpha and M^* parameters of our luminosity function are in good agreement with those of the AUTOFIB redshift survey (Ellis et al. 1996). Viceversa, our amplitude is significantly higher, by a factor ~ 1.6 at M ~ M^*, than that found for both the Stromlo-APM (Loveday et al. 1992) and the Las Campanas (Lin et al. 1996) redshift surveys. Also the faint end slope of our luminosity function is significantly steeper than that found in these two surveys. Large over- and under- densities are clearly seen in our data. In particular, we find evidence for a "local" underdensity (for D < 140 Mpc) and a significant overdensity at z ~ 0.1. When these radial density variations are taken into account, our derived luminosity function reproduces very well the observed counts for b_J < 19.4, including the steeper than Euclidean slope for b_J < 17.

E. Zucca; G. Zamorani; G. Vettolani; A. Cappi; R. Merighi; M. Mignoli; G. M. Stirpe; H. MacGillivray; C. Collins; C. Balkowski; V. Cayatte; S. Maurogordato; D. Proust; G. Chincarini; L. Guzzo; D. Maccagni; R. Scaramella; A. Blanchard; M. Ramella

1997-05-13T23:59:59.000Z

95

Compute Node MD3000 Storage Array  

E-Print Network (OSTI)

Compute Node MD3000 Storage Array Dell 2950 Head Node 24-Port Switch Compute Node Compute Node Compute Node Compute Node Compute Node Compute Node Compute Node Compute Node Compute Node Compute Node Compute Node Compute Node Compute Node Compute Node Compute Node Compute Node 24-Port Switch Dell 2950

Weber, David J.

96

Heart Failure Jason Ryan, MD, MPH  

E-Print Network (OSTI)

1 Heart Failure Jason Ryan, MD, MPH Director, UCONN Heart Failure Center University of Connecticut,084,000 $34.8 billion Background on Heart Failure Heart failure (HF) is a major public health problem resulting in substantial morbidity and mortality 1American Heart Association.2008 Heart and Stroke

Oliver, Douglas L.

97

Steam Reforming on Transition-metal Carbides from Density-functional Theory  

Science Conference Proceedings (OSTI)

A screening study of the steam reforming reaction on clean and oxygen covered early transition-metal carbides surfaces is performed by means of density-functional theory calculations. It is found that carbides provide a wide spectrum of reactivities, from too reactive via suitable to too inert. Several molybdenum-based systems are identified as possible steam reforming catalysts. The findings suggest that carbides provide a playground for reactivity tuning, comparable to the one for pure metals.

Vojvodic, Aleksandra

2012-05-11T23:59:59.000Z

98

A new approach in signal processing for sodium boiling noise detection by probability density function estimates  

Science Conference Proceedings (OSTI)

The probability density function (pdf) method of noise signal processing has been investigated for its capability and quality in detecting sodium boiling noise. In an attempt to identify proper features of the pdf for sodium boiling noise detection, the segmented areas under the pdf curves have been found sensitive to sodium boiling noise. New approaches have been followed in selecting the feature threshold and achieving the targeted probabilities for false and missed sodium boiling noise detection.

Reddy, C.P.; Singh, O.P.; Vyjayanthi, R.K.; Prabhakar, R.

1988-03-01T23:59:59.000Z

99

Fission barriers in actinides in covariant density functional theory: the role of triaxiality  

E-Print Network (OSTI)

Relativistic mean field theory allowing for triaxial deformations is applied for a systematic study of fission barriers in the actinide region. Different pairing schemes are studied in details and it is shown that covariant density functional theory is able to describe fission barriers on a level of accuracy comparable with non-relativistic calculations, even with the best phenomenological macroscopic+microscopic approaches. Triaxiality in the region of the first saddle plays a crucial role in achieving that.

H. Abusara; A. V. Afanasjev; P. Ring

2010-10-09T23:59:59.000Z

100

Probability Density Functions to Represent Magnetic Fields at the Solar Surface  

E-Print Network (OSTI)

Numerical simulations of magneto-convection and analysis of solar magnetogram data provide empirical probability density functions (PDFs) for the line-of-sight component of the magnetic field. In this paper, we theoretically explore effects of several types of PDFs on polarized Zeeman line formation. We also propose composite PDFs to account for randomness in both field strength and orientation. Such PDFs can possibly mimic random fields at the solar surface.

Sampoorna, M

2009-01-01T23:59:59.000Z

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


101

The Gamma Transitions, Level Densities and Gamma Strength Function of Isotopes Yb-172 and Sm-153  

E-Print Network (OSTI)

This report is presented the level densities and gamma strength function which is extracted from primary gamma transitions of (n,2g) measurement on the Dalat Nuclear Research Reactor (DNRR). The comparisons with others results and model calculations, there are outside the scope of uncertainty. These research results are showed that having of complement research for deformed nucleus in order to evaluate nuclear structure models.

Vuong Huu Tan; Pham Dinh Khang; Nguyen Xuan Hai; Ho Huu Thang; Dao Manh Trinh; Nguyen An Son

2013-08-22T23:59:59.000Z

102

DENSITY-FUNCTIONAL STUDY OF Zr-BASED ACTINIDE ALLOYS: 2. U-Pu-Zr SYSTEM  

Science Conference Proceedings (OSTI)

Density-functional theory, previously used to describe phase equilibria in the U-Zr alloys [1], is applied to study ground state properties of the bcc U-Pu-Zr solid solutions. Calculated heats of formation of the Pu-U and Pu-Zr alloys are in a good agreement with CALPHAD assessments. We found that account for spin-orbit coupling is important for successful description of Pu-containing alloys.

Landa, A; Soderlind, P; Turchi, P; Vitos, L; Ruban, A

2009-02-09T23:59:59.000Z

103

Application of nuclear density functionals to lepton number violating weak processes  

Science Conference Proceedings (OSTI)

We present an application of energy density functional methods with the Gogny interaction to the calculation of nuclear matrix elements (NME) for neutrinoless double beta decay and double electron capture. Beyond mean field effects have been included by particle number and angular momentum restoration and shape mixing within the generator coordinate method (GCM) framework. We analyze in detail the NME for {sup 116}Cd nucleus which is one of the most promising candidates to detect neutrinoless double beta decay.

Rodriguez, Tomas R.; Martinez-Pinedo, Gabriel [Technische Universitaet Darmstadt, Magdalenenstr. 12, D-64289, Darmstadt (Germany) and GSI Helmholtzzentrum fuer Schwerionenforschung, Plankstr. 1, D-64291 Darmstadt (Germany)

2012-10-20T23:59:59.000Z

104

Communication: Density functional theory overcomes the failure of predicting intermolecular interaction energies  

Science Conference Proceedings (OSTI)

Density-functional theory (DFT) revolutionized the ability of computational quantum mechanics to describe properties of matter and is by far the most often used method. However, all the standard variants of DFT fail to predict intermolecular interaction energies. In recent years, a number of ways to go around this problem has been proposed. We show that some of these approaches can reproduce interaction energies with median errors of only about 5% in the complete range of intermolecular configurations. Such errors are comparable to typical uncertainties of wave-function-based methods in practical applications. Thus, these DFT methods are expected to find broad applications in modelling of condensed phases and of biomolecules.

Podeszwa, Rafal [Institute of Chemistry, University of Silesia, Szkolna 9, 40-006 Katowice (Poland); Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716 (United States); Szalewicz, Krzysztof [Institute of Chemistry, University of Silesia, Szkolna 9, 40-006 Katowice (Poland)

2012-04-28T23:59:59.000Z

105

The Luminosity Function and Mean Galaxy Density from the ESP galaxy Redshift Survey  

E-Print Network (OSTI)

We summarise the main results obtained over the last two years by the ESO Slice Project (ESP) redshift survey, concerning the luminosity function and mean density of galaxies, and their implications for the galaxy number counts at bright magnitudes. The bj-band luminosity function is characterised by a steep faint-end, which raises above a "global" Schechter fit for M_bj > -17 + 5log(h) and is well described by a power-law with slope ~ -1.6. This steepening is mostly produced by galaxies with emission lines, with a clear trend for galaxies with larger [OII] equivalent widths to show a steeper faint end (and a fainter M*). The normalization of the luminosity function is about a factor of 1.6 higher that that from the Stromlo-APM survey. We find that, in fact, the mean density can be seen to increase out to ~140/h Mpc. If we take this into account when computing the expected cumulative number counts from the observed luminosity function, we are able to reproduce the observed steep counts at bright (bj<17) magnitudes very accurately.

E. Zucca; G. Zamorani; P. Vettolani

1998-10-06T23:59:59.000Z

106

A van der Waals density functional mapping of attraction in DNA dimers  

E-Print Network (OSTI)

The dispersion interaction between a pair of parallel DNA double-helix structures is investigated by means of the van der Waals density functional (vdW-DF) method. Each double-helix structure consists of an infinite repetition of one B-DNA coil with 10 base pairs. This parameter-free density functional theory (DFT) study illustrates the initial step in a proposed vdW-DF computational strategy for large biomolecular problems. The strategy is to first perform a survey of interaction geometries, based on the evaluation of the van der Waals (vdW) attraction, and then limit the evaluation of the remaining DFT parts (specifically the expensive study of the kinetic-energy repulsion) to the thus identified interesting geometries. Possibilities for accelerating this second step is detailed in a separate study. For the B-DNA dimer, the variation in van der Waals attraction is explored at relatively short distances (although beyond the region of density overlap) for a 360 degrees rotation. This study highlights the role...

Londero, Elisa; Schroder, Elsebeth

2013-01-01T23:59:59.000Z

107

A density functional theory and time-dependent density functional theory investigation on the anchor comparison of triarylamine-based dyes  

SciTech Connect

To understand the effects of the anchor part in organic dyes on the energy conversion efficiency of dye-sensitized solar cells (DSCs), two different anchor groups used in metal-free triphenylamine (TPA)-based organic dyes for DSCs have been theoretically compared. Density functional theory (DFT) and time-dependent DFT (TDDFT) study of geometry properties, excitations, and electronic structures of triarylamine-based dyes (TC1 and TPAR1) before and after binding to titanium has been performed under the level of TD-PBE1PBE/6-311G(d,p)//B3LYP/6-311G(d,p). The result shows that cyanoacrylic acid anchor favors better photoelectrochemical properties of DSCs than that of rhodanine-3-acetic acid anchor via providing more shift of TiO{sub 2} conduction band toward the vacuum energy levels (larger open circuit potentials) and more favorable conjugation with titanium. This study is expected to shed light on the design of metal-free organic dyes for DSCs.

Peng Bo; Yang Siqi; Li Lanlan; Cheng Fangyi; Chen Jun [Institute of New Energy Material Chemistry and Key Laboratory of Energy-Material Chemistry, Chemistry College, Nankai University, Tianjin 300071 (China)

2010-01-21T23:59:59.000Z

108

Free Energy Calculation in MD Simulation  

E-Print Network (OSTI)

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

Nielsen, Steven O.

109

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

Office of Legacy Management (LM)

Johns Hopkins University - MD 02 Johns Hopkins University - MD 02 FUSRAP Considered Sites Site: JOHNS HOPKINS UNIVERSITY (MD.02 ) Eliminated from further consideration under FUSRAP Designated Name: Not Designated Alternate Name: None Location: Baltimore , Maryland MD.02-1 Evaluation Year: 1987 MD.02-2 Site Operations: Conducted spectroscopic studies under contract number AT(49-1)-309. MD.02-1 Site Disposition: Eliminated - Potential for contamination considered remote based on limited quantities of material used in a controlled environment MD.02-2 Radioactive Materials Handled: Yes Primary Radioactive Materials Handled: Tritium MD.02-1 Radiological Survey(s): None Indicated Site Status: Eliminated from further consideration under FUSRAP Also see Documents Related to JOHNS HOPKINS UNIVERSITY

110

A study of the density functional methods on the photoabsorption of Bodipy dyes  

E-Print Network (OSTI)

Tunability of the photoabsorption and directional charge injection characteristics of Bodipy-based dye molecules with different carbonyl groups make them promising candidates for photovoltaic applications. In order to study the effect of screening in the Coulomb interaction on the electronic and optical properties of two Bodipy derivatives, we have used linear response time-dependent and exact exchange hybrid density functional approaches. The effect of linear and non-linear solvation models on the electrochemical properties of the dyes has also been discussed.

Unal, Hatice; Mete, Ersen

2013-01-01T23:59:59.000Z

111

Ferromagnetism in GaN: Gd: A density functional theory study  

SciTech Connect

First principle calculations of the electronic structure and magnetic interaction of GaN:Gd have been performed within the Generalized Gradient Approximation (GGA) of the density functional theory (DFT) with the on-site Coulomb energy U taken into account (also referred to as GGA+U). The ferromagnetic p-d coupling is found to be over two orders of magnitude larger than the s-d exchange coupling. The experimental colossal magnetic moments and room temperature ferromagnetism in GaN:Gd reported recently are explained by the interaction of Gd 4f spins via p-d coupling involving holes introduced by intrinsic defects such as Ga vacancies.

Stevenson, Cynthia; Stevenson, Cynthia

2008-02-04T23:59:59.000Z

112

Construction of the free energy landscape by the density functional theory  

E-Print Network (OSTI)

On the basis of the density functional theory, we give a clear definition of the free energy landscape. To show the usefulness of the definition, we construct the free energy landscape for rearrangement of atoms in an FCC crystal of hard spheres. In this description, the cooperatively rearranging region (CRR) is clealy related to the hard spheres involved in the saddle between two adjacent basins. A new concept of the simultaneously rearranging region (SRR) emerges naturally as spheres defined by the difference between two adjacent basins. We show that the SRR and the CRR can be determined explicitly from the free energy landscape. 1 1

Takashi Yoshidome; Akira Yoshimori; Takashi Odagaki

2005-01-01T23:59:59.000Z

113

Oxidation of stepped Pt(111) studied by x-ray photoelectron spectroscopy and density functional theory  

SciTech Connect

In this comparative density functional theory and x-ray photoelectron spectroscopy study on the interaction of oxygen with stepped Pt(111) surfaces, we show that both the initial adsorption and oxidation occur at the steps rather than terraces. An equivalent behavior was observed for the oxide formation at higher chemical potentials, where, after the formation of a one-dimensional PtO{sub 2}-type oxide at the steps, similar oxide chains form on the (111) terraces, indicating the initial stages of bulk oxide formation.

Bandlow, Jochen; Kaghazchi, Payam; Jacob, Timo [Institut fuer Elektrochemie, Universitaet Ulm, Albert-Einstein-Allee 47, D-89069 Ulm (Germany); Papp, C.; Traenkenschuh, B.; Streber, R.; Lorenz, M. P. A.; Fuhrmann, T.; Steinrueck, H.-P. [Lehrstuhl fuer Physikalische Chemie II, Universitaet Erlangen-Nuernberg, Egerlandstr. 3, D-91058 Erlangen (Germany); Denecke, R. [Wilhelm-Ostwald-Institut fuer Physikalische und Theoretische Chemie, Universitaet Leipzig, Linnestr. 2, D-04103 Leipzig (Germany)

2011-05-01T23:59:59.000Z

114

Troubleshooting time-dependent density-functional theory for photochemical applications: Oxirane  

Science Conference Proceedings (OSTI)

The development of analytic-gradient methodology for excited states within conventional time-dependent density-functional theory (TDDFT) would seem to offer a relatively inexpensive alternative to better established quantum-chemical approaches for the modeling of photochemical reactions. However, even though TDDFT is formally exact, practical calculations involve the use of approximate functional, in particular the TDDFT adiabatic approximation, the use of which in photochemical applications must be further validated. Here, we investigate the prototypical case of the symmetric CC ring opening of oxirane. We demonstrate by direct comparison with the results of high-quality quantum Monte Carlo calculations that, far from being an approximation on TDDFT, the Tamm-Dancoff approximation is a practical necessity for avoiding triplet instabilities and singlet near instabilities, thus helping maintain energetically reasonable excited-state potential energy surfaces during bond breaking. Other difficulties one would encounter in modeling oxirane photodynamics are pointed out.

Cordova, Felipe; Doriol, L. Joubert; Ipatov, Andrei; Casida, Mark E.; Filippi, Claudia; Vela, Alberto [Laboratoire de Chimie Theorique, Departement de Chimie Molecularie (DCM, UMR CNRS/UJF 5250), Institut de Chimie Moleculaire de Grenoble (ICMG, FR2607), Universite Joseph Fourier - Grenoble I, 301 rue de la Chimie, BP 53, F-38041 Grenoble Cedex 9 (France); Instituut-Lorentz for Theoretical Physics, Universiteit Leiden, Niels Bohrweg 2, Leiden NL-2333 CA Netherlands (Netherlands); Departamento de Quimica, Cinvestav, Avenida Instituto Politecnico Nacional 2508, A.P. 14-740, Mexico D.F. 07000 (Mexico)

2007-10-28T23:59:59.000Z

115

Equilibrium gas-liquid-solid contact angle from density-functional theory  

E-Print Network (OSTI)

We investigate the equilibrium of a fluid in contact with a solid boundary through a density-functional theory. Depending on the conditions, the fluid can be in one phase, gas or liquid, or two phases, while the wall induces an external field acting on the fluid particles. We first examine the case of a liquid film in contact with the wall. We construct bifurcation diagrams for the film thickness as a function of the chemical potential. At a specific value of the chemical potential, two equally stable films, a thin one and a thick one, can coexist. As saturation is approached, the thickness of the thick film tends to infinity. This allows the construction of a liquid-gas interface that forms a well defined contact angle with the wall.

Pereira, Antonio

2010-01-01T23:59:59.000Z

116

Energy density functional study of nuclear matrix elements for neutrinoless $??$ decay  

E-Print Network (OSTI)

We present an extensive study of nuclear matrix elements (NME) for the neutrinoless double beta decay of the nuclei $^{48}$Ca, $^{76}$Ge, $^{82}$Se, $^{96}$Zr, $^{100}$Mo, $^{116}$Cd, $^{124}$Sn, $^{128}$Te, $^{130}$Te, $^{136}$Xe, and $^{150}$Nd based on state-of-the-art energy density functional methods using the Gogny D1S functional. Beyond mean-field effects are included within the generating coordinate method with particle number and angular momentum projection for both initial and final ground states. We obtain a rather constant value for the NME's around 4.7 with the exception of $^{48}$Ca and $^{150}$Nd, where smaller values are found. We analyze the role of deformation and pairing in the evaluation of the NME and present detailed results for the decay of $^{150}$Nd.

Tomás R. Rodríguez; G. Martinez-Pinedo

2010-08-31T23:59:59.000Z

117

Electronic structure calculations with the Tran-Blaha modified Becke-Johnson Density Functional  

Science Conference Proceedings (OSTI)

We report a series of calculations testing the predictions of the Tran-Blaha functional for the electronic structure and magnetic properties of condensed systems. We find a general improvement in the properties of semiconducting and insulating systems, relative to calculations with standard generalized gradient approximations, although this is not always by the same mechanism as other approaches such as the quasiparticle GW method. In ZnO the valence bands are narrowed and the band gap is increased to a value in much better agreement with experiment. The Zn d states do not move to higher binding energy as they do in local-density approximation+U calculations. The functional is effective for systems with hydride anions, where correcting self-interaction errors in the 1s state is important. Similarly, it correctly opens semiconducting gaps in the alkaline-earth hexaborides. It correctly stabilizes an antiferromagnetic insulating ground state for the undoped cuprate parent CaCuO{sub 2}, but seriously degrades the agreement with experiment for ferromagnetic Gd relative to the standard local-spin-density approximation and generalized gradient approximations. This is due to positioning of the minority-spin 4f states at too low an energy. Conversely, the position of the La 4f conduction bands of La{sub 2}O{sub 3} is in reasonable accord with experiment as it is with standard functionals. The functional narrows the Fe d bands of the parent compound LaFeAsO of the iron high-temperature superconductors while maintaining the high Fe spectral weight near the Fermi energy.

Singh, David J [ORNL

2010-01-01T23:59:59.000Z

118

DOE - Office of Legacy Management -- Maryland Disposal Site - MD 05  

Office of Legacy Management (LM)

Maryland Disposal Site - MD 05 Maryland Disposal Site - MD 05 FUSRAP Considered Sites Site: MARYLAND DISPOSAL SITE (MD.05 ) Eliminated from consideration under FUSRAP Designated Name: Not Designated Alternate Name: None Location: Baltimore - Vicinity , Maryland MD.05-1 Evaluation Year: 1989 MD.05-1 Site Operations: Proposed disposal site - never developed. MD.05-1 Site Disposition: Eliminated Radioactive Materials Handled: None Indicated Primary Radioactive Materials Handled: None Indicated Radiological Survey(s): None Indicated Site Status: Eliminated from consideration under FUSRAP Also see Documents Related to MARYLAND DISPOSAL SITE MD.05-1 - Report (DOE/OR/20722-131 Revision 0); Site Plan for the Maryland Disposal Site; April 1989 Historical documents may contain links which are no longer valid or to

119

Probability Density Functions of Liquid Water Path and Total Water Content of Marine Boundary Layer Clouds: Implications for Cloud Parameterization  

Science Conference Proceedings (OSTI)

Mathematical forms of probability density functions (PDFs) of liquid water path (LWP) and total water content for marine boundary layer clouds are investigated using the homogeneity, skewness, and kurtosis of PDFs of LWP obtained from observations ...

Hideaki Kawai; Joăo Teixeira

2012-03-01T23:59:59.000Z

120

Small-Scale and Mesoscale Variability of Scalars in Cloudy Boundary Layers: One-Dimensional Probability Density Functions  

Science Conference Proceedings (OSTI)

A key to parameterization of subgrid-scale processes is the probability density function (PDF) of conserved scalars. If the appropriate PDF is known, then grid box average cloud fraction, liquid water content, temperature, and autoconversion can ...

Vincent E. Larson; Robert Wood; Paul R. Field; Jean-Christophe Golaz; Thomas H. Vonder Haar; William R. Cotton

2001-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "md density functional" from the National Library of EnergyBeta (NLEBeta).
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121

Density Functional Theory and Molecular Dynamics Studies on Energetics and Kinetics for Electro-Active Polymers: PVDF and P(VDF-TrFE)  

E-Print Network (OSTI)

We use first principles methods to study static and dynamical mechanical properties of the ferroelectric polymer Poly(vinylidene fluoride) (PVDF) and its copolymer with trifluoro ethylene (TrFE). We use density functional theory [within the generalized gradient approximation (DFT-GGA)] to calculate structures and energetics for various crystalline phases for PVDF and P(VDF-TrFE). We find that the lowest energy phase for PVDF is a non-polar crystal with a combination of trans (T) and gauche (G) bonds; in the case of the copolymer the role of the extra (bulkier) F atoms is to stabilize T bonds. This leads to the higher crystallinity and piezoelectricity observed experimentally. Using the MSXX first principles-based force field (FF) with molecular dynamics (MD), we find that the energy barrier necessary to nucleate a kink (gauche pairs separated by trans bonds) in an all-T crystal is much lower (14.9 kcal/mol) in P(VDF-TrFE) copolymer than in PVDF (24.8 kcal/mol). This correlates with the observation that the polar phase of the copolymer exhibits a solid-solid a transition to a non-polar phase under heating while PVDF directly melts. We also studied the mobility of an interface between a polar and non-polar phases under uniaxial stress; we find a lower threshold stress and a higher mobility in the copolymer as compared with PVDF. Finally, considering plastic deformation under applied shear, we find that the chains for P(VDF-TrFE) have a very low resistance to sliding, particularly along the chain direction. The atomistic characterization of these "unit mechanisms" provides essential input to mesoscopic or macroscopic models of electro-active polymers.

H. B. Su; Alejandro Strachan; William A. Goddard III

2004-08-09T23:59:59.000Z

122

Stress Isotherms of Porous Thin Materials: Theoretical Predictitions From a Nonlocal Density Functional Theory  

SciTech Connect

Recent beam bending (BB) experiments of microporous t31rns with very small pores have shown that the fluid confined in these pores exhibits monotonic compressive stresses as the relative pressure is varied from vacuum to saturation (relative vapor pressure, p/p. = 1). The variation of the stress near saturation is found to be linear in hz(p) and given by the saturated liquid density to within 20%. Capillary condensed fluids are traditionally described by the Laplace-Kelvin (LK) theory. LK theory correctly predicts the slope of the stress near saturation to be pl, but also predicts that the stress should be zero at saturation and tensile between saturation aud the capillary transition pressure. Hence LK theory does not capture the monotonic compressive stress observed in BB experiments. This report describes the results of density functional theory calculations for a simple fluid continued to a slit pore network. We show how the presence of even a small amount of polydispersity in pore size leads to both a monotonic compressive stress as well as the observed LK slope.

Frink, L.J.D.; van Swol, F.

1998-11-11T23:59:59.000Z

123

Steam reforming on transition-metal carbides from density-functional theory  

E-Print Network (OSTI)

A screening study of the steam reforming reaction (CH_4 + H_2O -> CO + 3H_2) on early transition-metal carbides (TMC's) is performed by means of density-functional theory calculations. The set of considered surfaces includes the alpha-Mo_2C(100) surfaces, the low-index (111) and (100) surfaces of TiC, VC, and delta-MoC, and the oxygenated alpha-Mo_2C(100) and TMC(111) surfaces. It is found that carbides provide a wide spectrum of reactivities towards the steam reforming reaction, from too reactive via suitable to too inert. The reactivity is discussed in terms of the electronic structure of the clean surfaces. Two surfaces, the delta-MoC(100) and the oxygen passivated alpha-Mo_2C(100) surfaces, are identified as promising steam reforming catalysts. These findings suggest that carbides provide a playground for reactivity tuning, comparable to the one for pure metals.

Vojvodic, Aleksandra

2009-01-01T23:59:59.000Z

124

Combinatorial density functional theory-based screening of surface alloys for the oxygen reduction reaction.  

DOE Green Energy (OSTI)

A density functional theory (DFT) -based, combinatorial search for improved oxygen reduction reaction (ORR) catalysts is presented. A descriptor-based approach to estimate the ORR activity of binary surface alloys, wherein alloying occurs only in the surface layer, is described, and rigorous, potential-dependent computational tests of the stability of these alloys in aqueous, acidic environments are presented. These activity and stability criteria are applied to a database of DFT calculations on nearly 750 binary transition metal surface alloys; of these, many are predicted to be active for the ORR but, with few exceptions, they are found to be thermodynamically unstable in the acidic environments typical of low-temperature fuel cells. The results suggest that, absent other thermodynamic or kinetic mechanisms to stabilize the alloys, surface alloys are unlikely to serve as useful ORR catalysts over extended periods of operation.

Greeley, J.; Norskov, J.; Center for Nanoscale Materials; Technical Univ. of Denmark

2009-03-26T23:59:59.000Z

125

Density-functional theory study of gramicidin A ion channel geometry and electronic properties  

E-Print Network (OSTI)

Understanding the mechanisms underlying ion channel function from the atomic-scale requires accurate ab initio modelling as well as careful experiments. Here, we present a density functional theory (DFT) study of the ion channel gramicidin A, whose inner pore conducts only monovalent cations and whose conductance has been shown to depend on the side chains of the amino acids in the channel. We investigate the ground-state geometry and electronic properties of the channel in vacuum, focusing on their dependence on the side chains of the amino acids. We find that the side chains affect the ground state geometry, while the electrostatic potential of the pore is independent of the side chains. This study is also in preparation for a full, linear scaling DFT study of gramicidin A in a lipid bilayer with surrounding water. We demonstrate that linear scaling DFT methods can accurately model the system with reasonable computational cost. Linear scaling DFT allows ab initio calculations with 10,000 to 100,000 atoms an...

Todorovi?, Milica; Gillan, M J; Miyazaki, Tsuyoshi

2013-01-01T23:59:59.000Z

126

Accuracy of Density Functional Theory in Prediction of Carbon Dioxide Adsorbent Materials  

E-Print Network (OSTI)

We have performed a thorough computational study to assess the accuracy of density functional theory (DFT) methods in describing the interactions of CO2 with model alkali-earth-metal (AEM, Ca and Li) decorated carbon structures, namely anthracene (C14H10) molecules. We find that gas-adsorption energy and equilibrium structure results obtained with both standard (i.e. LDA and GGA) and hybrid (i.e. PBE0 and B3LYP) exchange-correlation functionals of DFT differ significantly from results obtained with second-order Moller-Plesset perturbation theory (MP2), an accurate computational quantum chemistry method. The major disagreements found can be mostly rationalized in terms of electron correlation errors that lead to inaccurate charge transfers and electrostatic Coulomb interactions between the molecules. Interestingly, we show that when the concentration of AEM atoms in anthracene is tuned to resemble as closely as possible to the electronic structure of AEM-decorated graphene, hybrid exchange-correlation DFT and ...

Cazorla, Claudio

2012-01-01T23:59:59.000Z

127

Gravitational Clustering in Redshift Space: Non-Gaussian Tail of the Cosmological Density Distribution Function  

E-Print Network (OSTI)

We study the non-Gaussian tail of the probability distribution function of density in cosmological N-Body simulations for a variety of initial conditions. We compare the behaviour of the non-Gaussian tail in the real space with that in the redshift space. The form of the PDF in redshift space is of great significance as galaxy surveys probe this and not the real space analogue predicted using theoretical models. We model the non-Gaussian tail using the halo model. In the weakly non-linear regime the moments of counts in cells in the redshift space approach the values expected from perturbation theory for moments in real space. We show that redshift space distortions in the non-linear regime dominate over signatures of initial conditions or the cosmological background. We illustrate this using Skewness and higher moments of counts in cells, as well as using the form of the non-Gaussian tail of the distribution function. We find that at scales smaller than the scale of non-linearity the differences in Skewness, etc. for different models are very small compared to the corresponding differences in real space. We show that bias also leads to smaller values of higher moments, but the redshift space distortions are typically the dominant effect.

J. S. Bagla; Suryadeep Ray

2006-04-28T23:59:59.000Z

128

Precise evaluation of thermal response functions by optimized density matrix renormalization group schemes  

E-Print Network (OSTI)

This paper provides a study and discussion of earlier as well as novel more efficient schemes for the precise evaluation of finite-temperature response functions of strongly correlated quantum systems in the framework of the time-dependent density matrix renormalization group (tDMRG). The computational costs and bond dimensions as functions of time and temperature are examined for the example of the spin-1/2 XXZ Heisenberg chain in the critical XY phase and the gapped N\\'eel phase. The matrix product state purifications occurring in the algorithms are in one-to-one relation with corresponding matrix product operators. This notational simplification elucidates implications of quasi-locality on the computational costs. Based on the observation that there is considerable freedom in designing efficient tDMRG schemes for the calculation of dynamical correlators at finite temperatures, a new class of optimizable schemes, as recently suggested in arXiv:1212.3570, is explained and analyzed numerically. A specific novel near-optimal scheme that requires no additional optimization reaches maximum times that are typically increased by a factor of two, when compared against earlier approaches. These increased reachable times make many more physical applications accessible. For each of the described tDMRG schemes, one can devise a corresponding transfer matrix renormalization group (TMRG) variant.

Thomas Barthel

2013-01-10T23:59:59.000Z

129

Quasiparticle spectra from a nonempirical optimally tuned range-separated hybrid density functional  

SciTech Connect

We present a method for obtaining quasiparticle excitation energies from a DFT-based calculation, but with accuracy that is comparable to that of many-body perturbation theory within the GW approximation. The approach uses a range-separated hybrid density functional, with asymptotically exact and short-range fractional Fock exchange. The functional contains two parameters - the range separation and the short-range Fock fraction. Both are determined non-empirically, per system, based on satisfaction of exact physical constraints for the ionization potential and many-electron self-interaction, respectively. The accuracy of the method is demonstrated on the important benchmark molecule, 3,4,9,10-perylene-tetracarboxylic-dianydride (PTCDA), where it is shown to be the only non-empirical DFT-based method comparable to GW calculations. For any finite system, we envision that the approach could be useful directly as an inexpensive alternative to GW that offers good accuracy for both frontier and non-frontier quasiparticle excitation energies, opening the door to the studyof presently out of reach large-scale systems.

Refaely-Abramson, Sivan; Sharifzadeh, Sahar; Govind, Niranjan; Autschbach, Jochen; Neaton, Jeffrey B.; Baer, Roi; Kronik, Leeor

2012-11-28T23:59:59.000Z

130

Adaptive local basis set for Kohn-Sham density functional theory in a discontinuous Galerkin framework I: Total energy calculation  

E-Print Network (OSTI)

Kohn-Sham density functional theory is one of the most widely used electronic structure theories. Uniform discretization of the Kohn-Sham Hamiltonian generally results in a large number of basis functions per atom in order to resolve the rapid oscillations of the Kohn-Sham orbitals around the nuclei. Previous attempts to reduce the number of basis functions per atom include the usage of atomic orbitals and similar objects, but the atomic orbitals generally require fine tuning in order to reach the chemical accuracy. We present a novel discretization scheme that adaptively and systematically builds the rapid oscillations of the Kohn-Sham orbitals around the nuclei as well as environmental effects into the basis functions. The resulting basis functions are localized in the real space, and are discontinuous in the global domain. The continuous Kohn-Sham orbitals and the electron density are evaluated from the discontinuous basis functions using the discontinuous Galerkin (DG) framework. Our method is implemented...

Lin, Lin; Ying, Lexing; E, Weinan

2011-01-01T23:59:59.000Z

131

Spontaneous Fission Modes and Lifetimes of Superheavy Elements in the Nuclear Density Functional Theory  

Science Conference Proceedings (OSTI)

Background: The reactions with the neutron-rich 48Ca beam and actinide targets resulted in the detection of new superheavy (SH) nuclides with Z=104 118. The unambiguous identification of the new isotopes, however, still poses a problem because their -decay chains terminate by spontaneous fission (SF) before reaching the known region of the nuclear chart. The understanding of the competition between -decay and SF channels in SH nuclei is, therefore, of crucial importance for our ability to map the SH region and to assess its extent. Purpose: We perform self-consistent calculations of the competing decay modes of even-even SH isotopes with 108 Z 126 and 148 N 188. Methods: We use the state-of-the-art computational framework based on self-consistent symmetry-unrestricted nuclear density functional theory capable of describing the competition between nuclear attraction and electrostatic repulsion. We apply the SkM* Skyrme energy density functional. The collective mass tensor of the fissioning superfluid nucleus is computed by means of the cranking approximation to the adiabatic time-dependent Hartree-Fock-Bogoliubov (HFB) approach. This paper constitutes a systematic self-consistent study of spontaneous fission in the SH region, carried out at a full HFB level, that simultaneously takes into account both triaxiality and reflection asymmetry. Results: Breaking axial symmetry and parity turns out to be crucial for a realistic estimate of collective action; it results in lowering SF lifetimes by more than 7 orders of magnitude in some cases. We predict two competing SF modes: reflection symmetric modes and reflection asymmetric modes. Conclusions: The shortest-lived SH isotopes decay by SF; they are expected to lie in a narrow corridor formed by 280Hs, 284Fl, and 118284Uuo that separates the regions of SH nuclei synthesized in cold-fusion and hot-fusion reactions. The region of long-lived SH nuclei is expected to be centered on 294Ds with a total half-life of 1.5 days. Our survey provides a solid benchmark for the future improvements of self-consistent SF calculations in the region of SH nuclei.

Staszczak, A, [UTK/ORNL/Inst. Physics, Maria Curie-Sklodowska University, Poland; Baran, A. [UTK/ORNL/Inst. Physics, Maria Curie-Sklodowska University, Poland; Nazarewicz, Witold [UTK/ORNL/University of Warsaw

2013-01-01T23:59:59.000Z

132

Oral Histories: Pathologist Clarence Lushbaugh, M.D.  

NLE Websites -- All DOE Office Websites (Extended Search)

3 HUMAN RADIATION STUDIES: REMEMBERING THE EARLY YEARS Oral History of Pathologist Clarence Lushbaugh, M.D. Conducted October 5, 1994 United States Department of Energy Office of...

133

Development and evaluation of probability density functions for a set of human exposure factors  

Science Conference Proceedings (OSTI)

The purpose of this report is to describe efforts carried out during 1998 and 1999 at the Lawrence Berkeley National Laboratory to assist the U.S. EPA in developing and ranking the robustness of a set of default probability distributions for exposure assessment factors. Among the current needs of the exposure-assessment community is the need to provide data for linking exposure, dose, and health information in ways that improve environmental surveillance, improve predictive models, and enhance risk assessment and risk management (NAS, 1994). The U.S. Environmental Protection Agency (EPA) Office of Emergency and Remedial Response (OERR) plays a lead role in developing national guidance and planning future activities that support the EPA Superfund Program. OERR is in the process of updating its 1989 Risk Assessment Guidance for Superfund (RAGS) as part of the EPA Superfund reform activities. Volume III of RAGS, when completed in 1999 will provide guidance for conducting probabilistic risk assessments. This revised document will contain technical information including probability density functions (PDFs) and methods used to develop and evaluate these PDFs. The PDFs provided in this EPA document are limited to those relating to exposure factors.

Maddalena, R.L.; McKone, T.E.; Bodnar, A.; Jacobson, J.

1999-06-01T23:59:59.000Z

134

Carbon dioxide adsorption and activation on Ceria (110): A density functional theory study  

E-Print Network (OSTI)

Ceria (CeO2) is a promising catalyst for the reduction of carbon dioxide (CO2) to liquid fuels and commodity chemicals, in part because of its high oxygen storage capacity, yet the fundamentals of CO2 adsorption and initial activation on CeO2 surfaces remain largely unknown. We use density functional theory, corrected for onsite Coulombic interactions (DFT+U), to explore various adsorption sites and configurations for CO2 on stoichiometric and reduced CeO2 (110). Our model of reduced CeO2 (110) contains oxygen vacancies at the topmost atomic layer and undergoes surface reconstruction upon introduction of these vacancies. We find that CO2 adsorption on reduced CeO2 (110) is thermodynamically favored over the corresponding adsorption on stoichiometric CeO2 (110). The most stable adsorption configuration consists of CO2 adsorbed parallel to the reduced CeO2 (110) surface, with the molecule situated near the site of the oxygen vacancy. Structural changes in the CO2 molecule are also observed upon adsorption, so t...

Cheng, Zhuo; Lo, Cynthia S

2012-01-01T23:59:59.000Z

135

Study of Hydrogen Bonding in Small Water Clusters with Density Functional Theory Calculations  

DOE Green Energy (OSTI)

The unique characteristics of hydrogen bonding have left our understanding of liquid water far from complete in terms of its structure and properties. In order to better describe the hydrogen bond in water, we seek to understand the electronic states which show sensitivity to hydrogen bonding. We investigate the structure of unoccupied valence states by performing X-ray Absorption calculations on water clusters using Density Functional Theory. For each water cluster, studying how valence electronic structure is perturbed by changes in the local hydrogen bonding environment facilitates our description of the hydrogen bond. Also in this framework, we move toward a depiction of local structures in liquid water by comparison to experimental X-ray absorption spectra. We find consistent localization along internal bonds in the electronic structures of pre- and post-edge states for single-donor species. In addition, we propose a molecular orbital bonding-antibonding picture to explain this directional localization from dimer calculations, and show that the pre- and post-edge spectral regions have a resulting relationship.

Wendlandt, Johanna; /Wisconsin U., Madison /SLAC, SSRL

2005-12-15T23:59:59.000Z

136

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

Office of Legacy Management (LM)

Inc - MD 04 Inc - MD 04 FUSRAP Considered Sites Site: MAX ZUCKERMAN & SONS, INC. (MD.04 ) Eliminated from consideration under FUSRAP Designated Name: Not Designated Alternate Name: Maryland Alloys Corporation MD.04-1 Location: 5245 Fairlawn Avenue , Baltimore , Maryland MD.04-2 Evaluation Year: 1994 MD.04-1 MD.04-3 Site Operations: Scrap metals broker that arranged purchases of materials for third party buyers. MD.04-2 MD.04-4 Site Disposition: Eliminated - Potential for contamination remote MD.04-3 Radioactive Materials Handled: Yes Primary Radioactive Materials Handled: Uranium (Q-11) Oxide/Residue MD.04-2 MD.04-4 Radiological Survey(s): Yes MD.04-1 Site Status: Eliminated from consideration under FUSRAP MD.04-3 Also see Documents Related to MAX ZUCKERMAN & SONS, INC.

137

Efficiency of caviton formation as a function of plasma density gradient  

SciTech Connect

The effect of a zeroth-order density gradient on the development of cavitons has been investigated experimentally and numerically. The cavitons were produced via excitation of electron plasma waves (EPW) with a modest ({ital E}{sup 2}/4{pi}{ital nT}{sub {ital e}}{much lt}1) resonant radio-frequency pump. The location of the resonance, on an inverse-parabolic density profile, was varied, with all other parameters being held constant. The depth of the caviton, and the strength of its associated trapped electric fields, are found to depend strongly on the density gradient scale length at the critical layer, with a maximum occurring when this length is infinite, at the flat top of the density profile. The results are accounted for by the dependence on the density gradient of the EPW convection rate and wave-breaking time. The study helps illuminate recent large-scale ionospheric density modification experiments.

Bauer, B.S.; Wong, A.Y.; Scurry, L.; Decyk, V.K. (Department of Physics, University of California, Los Angeles, Los Angeles, California 90024 (USA))

1990-08-01T23:59:59.000Z

138

Net Zero Residential Test Facility Gaithersburg, MD Solar Photovoltaic Panels  

E-Print Network (OSTI)

1 Net Zero Residential Test Facility Gaithersburg, MD Solar Photovoltaic Panels Solar Thermal R-35 Rim Joist Area 5" open cell spray foam 2" mineral wool insulation blanket R-10 Basement Slab electric WH #12;NZERTF Gaithersburg, MD Solar Photovoltaic Array Roof Mounted South half of main roof

Oak Ridge National Laboratory

139

Understanding of Ethanol Decomposition on Rh(111) From Density Functional Theory and Kinetic Monte Carlo Simulations  

DOE Green Energy (OSTI)

Reaction mechanisms of ethanol decomposition on Rh(1 1 1) were elucidated by means of periodic density functional theory (DFT) calculations and kinetic Monte Carlo (KMC) simulations. We propose that the most probable reaction pathway is via CH{sub 3}CH{sub 2}O* on the basis of our mechanistic study: CH{sub 3}CH{sub 2}OH* {yields} CH{sub 3}CH{sub 2}O* {yields} CH{sub 2}CH{sub 2}O* {yields} CH{sub 2}CHO* {yields} CH{sub 2}CO* {yields} CHCO* {yields} CH* + CO* {yields} C* + CO*. In contrast, the contribution from the pathway via CH{sub 3}CHOH* is relatively small, CH{sub 3}CH{sub 2}OH* {yields} CH{sub 3}CHOH* {yields} CH{sub 3}CHO* {yields} CH{sub 3}CO* {yields} CH{sub 2}CO* {yields} CHCO* {yields} CH* + CO* {yields} C* + CO*. According to our calculations, one of the slow steps is the formation of the oxametallacycle CH{sub 2}CH{sub 2}O* species, which leads to the production of CHCO*, the precursor for C-C bond breaking. Finally, the decomposition of ethanol leads to the production of C and CO. Our calculations, for ethanol combustion on Rh, the major obstacle is not C-C bond cleavage, but the C contamination on Rh(1 1 1). The strong C-Rh interaction may deactivate the Rh catalyst. The formation of Rh alloys with Pt and Pd weakens the C-Rh interaction, easing the removal of C, and, as expected, in accordance with the experimental findings, facilitating ethanol combustion.

Liu, P.; Choi, Y.M.

2011-05-16T23:59:59.000Z

140

Density Functional Theory Study of Methanol Decomposition on the CeO2(110) Surface  

Science Conference Proceedings (OSTI)

Methanol decomposition on the stoichiometric CeO2(110) surface has been investigated using density functional theory slab calculations. Three possible initial steps to decompose methanol by breaking one of three bonds (O?H, C?O and C?H) of methanol were examined. The relative order of thermodynamic stability for the three possible bond scission steps is: C?H > O?H > C?O. We further isolated transition state and determined activation energy for each bond-breaking mode using the nudged elastic method. The activation barrier for the most favorable dissociation mode, the O?H bond scission, is 0.3 eV on the (110) surface. An even lower activation barrier ( C?O > C?H. Our results are consistent with the previous experimental observation that methoxy is the dominant surface species after a stoichiometric CeO2 surface was exposed to methanol. The experimentally observed methanol chemistry was determined by the kinetics of initial dissociation steps rather than the thermodynamic stability of product states. Surface coverage of methanol was found to affect the relative stability between molecular and dissociative adsorption modes. Dissociative adsorption modes are preferred thermodynamically for methanol coverage up to 0.5 ML but only molecular adsorption was stable at full monolayer coverage. This work was supported by a Laboratory Directed Research and Development (LDRD) project of the Pacific Northwest National Laboratory (PNNL). The computations were performed using the Molecular Science Computing Facility in the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL), which is a U.S. Department of Energy national scientific user facility located at PNNL in Richland, Washington. Computing time was made under a Computational Grand Challenge “Computational Catalysis”. Part of the computing time was also granted by the National Energy Research Scientific Computing Center (NERSC).

Mei, Donghai; Deskins, N. Aaron; Dupuis, Michel; Ge, Qingfeng

2008-03-20T23:59:59.000Z

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


141

Method of sampling certain probability densities without inversion of their distribution functions  

SciTech Connect

A Monte Carlo device is described which bypasses the inversion x = p/sup -1/(r) involved in directly sampling the distribution P(x) of a stochastic variable x with given density p(x). The method is practical for all linear and a broad class of quadratic densities. (auth)

Everett, C.J.; Cashwell, E.D.; Turner, G.D.

1973-09-01T23:59:59.000Z

142

Recent advances in the use of density functional theory to design efficient solar energy-based renewable systems  

Science Conference Proceedings (OSTI)

This article reviews the use of Density Functional Theory (DFT) to study the electronic and optical properties of solar-active materials and dyes used in solar energy conversion applications (dye-sensitized solar cells and water splitting). We first give a brief overview of the DFT its development

Ramy Nashed; Yehea Ismail; Nageh K. Allam

2013-01-01T23:59:59.000Z

143

Supplemental Material for Angular Momentum Dependent Orbital Free Density Functional Theory  

E-Print Network (OSTI)

for Energy and the Environment, Princeton University, Princeton, New Jersey 08544, USA 2 Material Science region [Fig. 1(c)], (r) = R R(rR) + I(r), (1) where R(rR) is the electron density inside the MT sphere centered on site R, I(r) is the interstitial electron density which is 0 inside the spheres and rR = r - R

Florian, Libisch

144

Oxygen Reduction Reaction on Dispersed and Core-Shell Metal Alloy Catalysts: Density Functional Theory Studies  

E-Print Network (OSTI)

Pt-based alloy surfaces are used to catalyze the electrochemical oxygen reduction reaction (ORR), where molecular oxygen is converted into water on fuel cell electrodes. In this work, we address challenges due to the cost of high Pt loadings in the cathode electrocatalyst, as well as those arising from catalyst durability. We aim to develop an increased understanding of the factors that determine ORR activity together with stability against surface segregation and dissolution of Pt-based alloys. We firstly focus on the problem of determining surface atomic distribution resulting from surface segregation phenomena. We use first-principles density functional theory (DFT) calculations on PtCo and Pt3Co overall compositions, as well as adsorption of water and atomic oxygen on PtCo(111) and Pt-skin structures. The bonding between water and surfaces of PtCo and Pt-skin monolayers are investigated in terms of orbital population. Also, on both surfaces, the surface reconstruction effect due to high oxygen coverage and water co-adsorption is investigated. Although the PtCo structures show good activity, a large dissolution of Co atoms tends to occur in acid medium. To tackle this problem, we examine core-shell structures which showed improved stability and activity compared to Pt(111), in particular, one consisting of a surface Pt-skin monolayer over an IrCo or Ir3Co core, with or without a Pd interlayer between the Pt surface and the Ir-Co core. DFT analysis of surface segregation, surface stability against dissolution, surface Pourbaix diagrams, and reaction mechanisms provide useful predictions on catalyst durability, onset potential for water oxidation, surface atomic distribution, coverage of oxygenated species, and activity. The roles of the Pd interlayer in the core-shell structures that influence higher ORR activity are clarified. Furthermore, the stability and activity enhancement of new shell-anchor-core structures of Pt/Fe-C/core, Pt/Co-C/core and Pt/Ni-C/core are demonstrated with core materials of Ir, Pd3Co, Ir3Co, IrCo and IrNi. Based on the analysis, Pt/Fe-C/Ir, Pt/Co-C/Ir, Pt/Ni-C/Ir, Pt/Co-C/Pd3Co, Pt/Fe-C/Pd3Co, Pt/Co- C/Ir3Co, Pt/Fe-C/Ir3Co, Pt/Co-C/IrCo, Pt/Co-C/IrNi, and Pt/Fe-C/IrNi structures show promise in terms of both improved durability and relatively high ORR activity.

Hirunsit, Pussana

2010-08-01T23:59:59.000Z

145

Density Functional Theory Study of Surface Carbonate Formation on BaO(001)  

Science Conference Proceedings (OSTI)

Periodic density functional theory calculations have been used to study the formation and stability of surface carbonate on BaO(001) upon CO2 exposures. CO2 adsorbs at Lewis basic Os site forming anionic surface carbonate ( ) species until one monolayer coverage (1ML). Certain amount of electrons has been transferred from the surface to CO2 after CO2 adsorption. The adsorption energy of CO2 decreases with the increasing coverage as a combinative result of the less electrons accepted by each adsorbed CO2 and the lateral repulsive interactions. At ?CO2 0.75 ML, dramatic surface reconstruction had been found for the parallel pattern of surface carbonates that initially arranged on BaO(001). Due to strong lateral repulsion between the surface carbonates, the surface reconstruction actually pulls the surface Ba atom out of the surface plane, suggesting a possible onset of phase transition from surface carbonate overlayer to crystalline bulk-like barium carbonate. Surface free energy calculations have been performed to study the stability of surface carbonate at different temperature and pressure conditions. Our calculations indicate that surface carbonates decompose at 850 K at low coverage. For the fully covered carbonate overlayer, surface carbonate will become unstable at about 600 K. This is in good agreement with previous experimental observations. Finally, the effect of surface hydroxyl on the stability of surface carbonate is investigated. At low hydroxyl coverage, the neighboring hydroxyl stabilizes surface carbonate. On the fully hydroxylated BaO surface, the chelating bicarbonate instead of surface carbonate is formed upon CO2 adsorption. This work, performed in the Institute for Interfacial Catalysis at Pacific Northwest National Laboratory (PNNL), was partially supported by a PNNL Laboratory Directed Research and Development (LDRD) project. Computing time was granted by the National Energy Research Scientific Computing Center (NERSC) under project No. m752, and also by the scientific user project (st30469) using the Molecular Science Computing Facility in the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL). The EMSL is a U.S. DOE national scientific user facility located at PNNL, and supported by the DOE’s Office of Biological and Environmental Research.

Mei, Donghai

2010-02-04T23:59:59.000Z

146

Sub-L* Galaxies at Redshifts z~4, 3, and 2: Their UV Luminosity Function and Luminosity Density  

E-Print Network (OSTI)

We use very deep (R_lim=27) UGRI imaging to study the evolution of the faint end of the UV-selected galaxy luminosity function from z~4 to z~2. We find that the luminosity function evolves with time and that this evolution is differential with luminosity: the number of sub-L* galaxies increases from z~4 to z~3 by at least a factor of 2.3, while the bright end of the LF remains unchanged. Potential systematic biases restrict our ability to draw strong conclusions at lower redshifts, z~2, but we can say that the number density of sub-L* galaxies at z~2.2 is at least as high as it is at z~3. Turning to the UV luminosity density of the Universe, we find that the luminosity density starts dropping with increasing redshift already beginning at z=3 (earlier than recently thought - Steidel et al. 1999) and that this drop is dominated by the same sub-L* galaxies that dominate the evolution of the LF. This differential evolution of the luminosity function suggests that differentially comparing key diagnostics of dust, stellar populations, etc. as a function of z and L should let us isolate the key mechanisms that drive galaxy evolution at high redshift.

Marcin Sawicki; David Thompson

2005-09-15T23:59:59.000Z

147

DOE - Office of Legacy Management -- Armco-Rustless Iron and Steel - MD 03  

Office of Legacy Management (LM)

Armco-Rustless Iron and Steel - MD Armco-Rustless Iron and Steel - MD 03 FUSRAP Considered Sites Site: Armco-Rustless Iron & Steel (MD.03 ) Eliminated from consideration under FUSRAP Designated Name: Not Designated Alternate Name: ARMCO Baltimore Works MD.03-1 Location: Baltimore , Maryland MD.03-2 Evaluation Year: 1987 MD.03-1 Site Operations: Test rolling of uranium billets. MD.03-2 MD.03-3 Site Disposition: Eliminated - Potential for contamination remote due to limited quantity of material and duration of test MD.03-1 Radioactive Materials Handled: Yes Primary Radioactive Materials Handled: Uranium MD.03-2 Radiological Survey(s): Health and safety monitoring conducted during operations MD.03-2 Site Status: Eliminated from consideration under FUSRAP MD.03-1 Also see

148

MD. SAIFUR RAHAMAN 9 Hillhouse Ave., Environmental Engineering Program  

E-Print Network (OSTI)

of Chemical Engineering, Yale University Project: "Environmental implications and applications of engineeredMD. SAIFUR RAHAMAN 9 Hillhouse Ave., Environmental Engineering Program Department of Chemical Crystallization in a Fluidized Bed Reactor: Kinetics, Hydrodynamics and Performance" Supervisor: Professor Donald

Elimelech, Menachem

149

Cove Point, MD Natural Gas Liquefied Natural Gas Imports from...  

Gasoline and Diesel Fuel Update (EIA)

Trinidad and Tobago (Million Cubic Feet) Cove Point, MD Natural Gas Liquefied Natural Gas Imports from Trinidad and Tobago (Million Cubic Feet) Year Jan Feb Mar Apr May Jun Jul Aug...

150

Cove Point, MD Natural Gas Liquefied Natural Gas Imports from...  

Annual Energy Outlook 2012 (EIA)

Norway (Million Cubic Feet) Cove Point, MD Natural Gas Liquefied Natural Gas Imports from Norway (Million Cubic Feet) Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 2011...

151

Cove Point, MD Natural Gas Liquefied Natural Gas Imports from...  

Annual Energy Outlook 2012 (EIA)

Nigeria (Million Cubic Feet) Cove Point, MD Natural Gas Liquefied Natural Gas Imports from Nigeria (Million Cubic Feet) Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 2011...

152

Cove Point, MD Natural Gas Liquefied Natural Gas Imports from...  

U.S. Energy Information Administration (EIA) Indexed Site

Algeria (Million Cubic Feet) Cove Point, MD Natural Gas Liquefied Natural Gas Imports from Algeria (Million Cubic Feet) Decade Year-0 Year-1 Year-2 Year-3 Year-4 Year-5 Year-6...

153

Cove Point, MD Natural Gas Liquefied Natural Gas Imports from...  

U.S. Energy Information Administration (EIA) Indexed Site

Egypt (Million Cubic Feet) Cove Point, MD Natural Gas Liquefied Natural Gas Imports from Egypt (Million Cubic Feet) Decade Year-0 Year-1 Year-2 Year-3 Year-4 Year-5 Year-6 Year-7...

154

Simulation Of Wave Function And Probability Density Of Modified Poschl Teller Potential Derived Using Supersymmetric Quantum Mechanics  

Science Conference Proceedings (OSTI)

SUSY quantum mechanics can be applied to solve Schrodinger equation for high dimensional system that can be reduced into one dimensional system and represented in lowering and raising operators. Lowering and raising operators can be obtained using relationship between original Hamiltonian equation and the (super) potential equation. In this paper SUSY quantum mechanics is used as a method to obtain the wave function and the energy level of the Modified Poschl Teller potential. The graph of wave function equation and probability density is simulated by using Delphi 7.0 programming language. Finally, the expectation value of quantum mechanics operator could be calculated analytically using integral form or probability density graph resulted by the programming.

Angraini, Lily Maysari [STKIP Hamzanwadi Selong East Lombok, NTB, PostGraduate student at Physics Department UNS, Jl. Ir. Sutami 36 A, Surakarta (Indonesia); Suparmi,; Variani, Viska Inda [Physics Department UNS, Jl. Ir. Sutami 36 A, Surakarta (Indonesia)

2010-12-23T23:59:59.000Z

155

Optimization of density functional tight-binding and classical reactive molecular dynamics for high-throughput simulations of carbon materials  

Science Conference Proceedings (OSTI)

Carbon materials and nanostructures (fullerenes, nanotubes) are promising building blocks of nanotechnology. Potential applications include optical and electronic devices, sensors, and nano-scale machines. The multiscale character of processes related ... Keywords: ACM proceedings, BLAS, Cray XT5, LAPACK, advanced materials, density-functional tight binding, high-throughput, linear algebra, material science, molecular dynamics, multiscale-modeling, quantum chemistry, scientific libraries, scientific-computing

Jacek Jakowski; Bilel Hadri; Steven J. Stuart; Predrag Krstic; Stephan Irle; Dulma Nugawela; Sophya Garashchuk

2012-07-01T23:59:59.000Z

156

Restoration of the Derivative Discontinuity in Kohn-Sham Density Functional Theory: An Efficient Scheme for Energy Gap Correction  

E-Print Network (OSTI)

From the perspective of perturbation theory, we propose a systematic procedure for the evaluation of the derivative discontinuity (DD) of the exchange-correlation energy functional in Kohn-Sham density functional theory (KS-DFT), wherein the exact DD can in principle be obtained by summing up all the perturbation corrections to infinite order. Truncation of the perturbation series at low order yields an efficient scheme for obtaining the approximate DD. While the zeroth-order theory yields a vanishing DD, the first-order correction to the DD can be expressed as an explicit universal functional of the ground-state density and the KS lowest unoccupied molecular orbital density, allowing the direct evaluation of the DD in the standard KS method without extra computational cost. The fundamental gap can be predicted by adding the estimated DD to the KS gap. This scheme is shown to be accurate in the prediction of the fundamental gaps for a wide variety of atoms and molecules.

Jeng-Da Chai; Po-Ta Chen

2012-11-03T23:59:59.000Z

157

Comparison of Small Polaron Migration and Phase Separation in Olivine LiMnPO? and LiFePO? using Hybrid Density Functional Theory  

E-Print Network (OSTI)

Using hybrid density functional theory based on the Heyd-Scuseria-Ernzerhof (HSE06) functional, we compared polaron migration and phase separation in olivine LiMnPO? to LiFePO?. The barriers for free hole and electron ...

Ong, Shyue Ping

158

More accurate and efficient bath spectral densities from super-resolution  

E-Print Network (OSTI)

Quantum transport and other phenomena are typically modeled by coupling the system of interest to an environment, or bath, held at thermal equilibrium. Realistic bath models are at least as challenging to construct as models for the quantum systems themselves, since they must incorporate many degrees of freedom that interact with the system on a wide range of timescales. Owing to computational limitations, the environment is often modeled with simple functional forms, with a few parameters fit to experiment to yield semi-quantitative results. Growing computational resources have enabled the construction of more realistic bath models from molecular dynamics (MD) simulations. In this paper, we develop a numerical technique to construct these atomistic bath models with better accuracy and decreased cost. We apply a novel signal processing technique, known as super-resolution, combined with a dictionary of physically-motivated bath modes to derive spectral densities from MD simulations. Our approach reduces the required simulation time and provides a more accurate spectral density than can be obtained via standard Fourier transform methods. Moreover, the spectral density is provided as a convenient closed-form expression which yields an analytic time-dependent bath kernel. Exciton dynamics of the Fenna-Matthews-Olsen light-harvesting complex are simulated with a second order time-convolutionless master equation, and spectral densities constructed via super-resolution are shown to reproduce the dynamics using only a quarter of the amount of MD data.

Thomas Markovich; Samuel M. Blau; John Parkhill; Christoph Kreisbeck; Jacob N. Sanders; Xavier Andrade; Alán Aspuru-Guzik

2013-07-16T23:59:59.000Z

159

Security Standards for the Global Information Grid Gary Buda, Booz Allen & Hamilton, Linthicum, MD 21090  

E-Print Network (OSTI)

, Telcordia Technologies, Morristown, NJ 07960 Chris Kubic, Department of Defense, Ft. Meade, MD, 20755

Lee, Ruby B.

160

QCD at nonzero density and canonical partition functions with Wilson fermions  

SciTech Connect

We present a reduction method for Wilson-Dirac fermions with nonzero chemical potential which generates a dimensionally reduced fermion matrix. The size of the reduced fermion matrix is independent of the temporal lattice extent and the dependence on the chemical potential is factored out. As a consequence the reduced matrix allows a simple evaluation of the Wilson fermion determinant for any value of the chemical potential and hence the exact projection to the canonical partition functions.

Alexandru, Andrei [Physics Department, George Washington University Washington, D.C. 20052 (United States); Wenger, Urs [Albert Einstein Center for Fundamental Physics, Institute for Theoretical Physics, Sidlerstrasse 5, CH-3012 Bern (Switzerland)

2011-02-01T23:59:59.000Z

Note: This page contains sample records for the topic "md density functional" from the National Library of EnergyBeta (NLEBeta).
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they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
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161

TO J. A. QuigUy, M.D. NATIONALLPADCW~  

Office of Legacy Management (LM)

J. A. QuigUy, M.D. J. A. QuigUy, M.D. NATIONALLPADCW~ OF oliI0 Cincbnati 39, Ohio September 23, 1960 TRIP RBPCRT TO PIONRBR DIVISION, BENDIX AVI4TIONC~ ION, DAVBNPQRT, SOWA,oNSEPTEMBR6-9,196O F. J. Klein CENTRAL FILE The purpose of this trip was tot (1) determine if a Bendix ronic energy cleaning system can clean uranium-contaminated drums to the extent of rcduciug the @ha ccmtazuinatiou level belav that required for sale as %oa-contaminatecl** by AEC Manual Chapter 5182-0s UOOO a dMlOO& average and at peak not more than 25,OOO a d~lOOcm2, and (2) observe . the health and safety aspects of the wotk and insure the adequate decontauimtiou of the machinery, tools, equi~t, aud teat area. This waa a wet operation Md the tauk waa not ventilated; hawever, should

162

Core and Valence Excitations in Resonant X-ray Spectroscopy using Restricted Excitation Window Time-dependent Density Functional Theory  

Science Conference Proceedings (OSTI)

We report simulations of X-ray absorption near edge structure (XANES), resonant inelastic X-ray scattering (RIXS) and 1D stimulated X-ray Raman spectroscopy (SXRS) signals of cysteine at the oxygen, nitrogen and sulfur K and L2,3 edges. The simulated XANES signals from the restricted window time-dependent density functional theory (REW-TDDFT) and the static exchange (STEX) method are compared with experiments, showing that REW-TDDFT is more accurate and computationally less expensive than STEX. Simulated RIXS and 1D SXRS signals from REW-TDDFT give some insights on the correlation of different excitations in the molecule.

Zhang, Yu; Biggs, Jason D.; Healion, Daniel; Govind, Niranjan; Mukamel, Shaul

2012-11-21T23:59:59.000Z

163

Density Dependence of the Mass Function of Globular Star Clusters in the Sombrero Galaxy and its Dynamical Implications  

E-Print Network (OSTI)

We have constructed the mass function of globular star clusters in the Sombrero galaxy in bins of different internal half-mass density rho_h and projected galactocentric distance R. This is based on the published measurements of the magnitudes and effective radii of the clusters by Spitler et al. (2006) in BVR images taken with the ACS on HST. We find that the peak of the mass function M_p increases with rho_h by a factor of about 4 but remains nearly constant with R. Our results are almost identical to those presented recently by McLaughlin & Fall (2007) for globular clusters in the Milky Way. The mass functions in both galaxies agree with a simple, approximate model in which the clusters form with a Schechter initial mass function and evolve subsequently by stellar escape driven by internal two-body relaxation. These findings therefore undermine recent claims that the present peak of the mass function of globular clusters must have been built into the initial conditions.

Rupali Chandar; S. Michael Fall; Dean E. McLaughlin

2007-09-10T23:59:59.000Z

164

DEFLAGRATION-TO-DETONATION TRANSITION IN LX-04 AS A FUNCTION OF LOADING DENSITY, TEMPERATURE, AND CONFINEMENT  

DOE Green Energy (OSTI)

The potential for deflagration-to-detonation transition (DDT) in LX-04 (85/15 HMX/Viton) is being evaluated as a function of loading density, temperature, and confinement. In the high confinement arrangement, a matrix of tests will be performed with the LX-04 loaded at {approx}50, 70, 90, and {approx}99 %TMD; and temperatures of ambient, 160 C, and 190 C, at each loading density. A more limited set of tests at medium confinement will be conducted. As expected, LX-04 does not undergo DDT at near TMD loadings in both medium and high confinement, although the later still results in significant fragmentation. In high confinement at pour density (50.3 %TMD), LX-04 does not transit to detonation at 160 C, but does at ambient and 190 C with the shortest run distance to detonation (l) at ambient temperature. With a 70% TMD loading at ambient temperature, l was even less. The limited ambient temperature measurements for l in high confinement are similar to previous data for 91/9 HMX/wax, which has nearly the same %volume of HMX as LX-04.

Sandusky, H W; Granholm, R H; Bohl, D G; Hare, D E; Vandersall, K S; Garcia, F

2005-06-01T23:59:59.000Z

165

Density Functional Theory Simulations Predict New Materials for Magnesium-Ion Batteries (Fact Sheet), NREL Highlights, Science  

SciTech Connect

Multivalence is identified in the light element, B, through structure morphology. Boron sheets exhibit highly versatile valence, and the layered boron materials may hold the promise of a high-energy-density magnesium-ion battery. Practically, boron is superior to previously known multivalence materials, especially transition metal compounds, which are heavy, expensive, and often not benign. Based on density functional theory simulations, researchers at the National Renewable Energy Laboratory (NREL) have predicted a series of stable magnesium borides, MgB{sub x}, with a broad range of stoichiometries, 2 < x < 16, by removing magnesium atoms from MgB{sub 2}. The layered boron structures are preserved through an in-plane topological transformation between the hexagonal lattice domains and the triangular domains. The process can be reversibly switched as the charge transfer changes with Mg insertion/extraction. The mechanism of such a charge-driven transformation originates from the versatile valence state of boron in its planar form. The discovery of these new physical phenomena suggests the design of a high-capacity magnesium-boron battery with theoretical energy density 876 mAh/g and 1550 Wh/L.

2011-10-01T23:59:59.000Z

166

Fast Calculations of Electrostatic Solvation Free Energy from Reconstructed Solvent Density Using Proximal Radial Distribution Functions  

SciTech Connect

Although detailed atomic models may be applied for a full description of solvation, simpler phenomenologicalmodels are particularly useful to interpret the results for scanning many large, complex systems, where a full atomic model is too computationally expensive to use. Among the most costly are solvation free-energy evaluations by simulation. Here we develop a fast way to calculate electrostatic solvation free energy while retaining much of the accuracy of explicit solvent free-energy simulation. The basis of our method is to treat the solvent not as a structureless dielectric continuum but as a structured medium by making use of universal proximal radial distribution functions. Using a deca-alanine peptide as a test case, we compare the use of our theory with free-energy simulations and traditional continuum estimates of the electrostatic solvation free energy.

Lin, Bin; Wong, Ka-Yiu; Hu, Char Y.; Kokubo, Hironori; Pettitt, Bernard M.

2011-07-07T23:59:59.000Z

167

New density functional theory approaches for enabling prediction of chemical and physical properties of plutonium and other actinides.  

SciTech Connect

Density Functional Theory (DFT) based Equation of State (EOS) construction is a prominent part of Sandia's capabilities to support engineering sciences. This capability is based on amending experimental data with information gained from computational investigations, in parts of the phase space where experimental data is hard, dangerous, or expensive to obtain. A prominent materials area where such computational investigations are hard to perform today because of limited accuracy is actinide and lanthanide materials. The Science of Extreme Environment Lab Directed Research and Development project described in this Report has had the aim to cure this accuracy problem. We have focused on the two major factors which would allow for accurate computational investigations of actinide and lanthanide materials: (1) The fully relativistic treatment needed for materials containing heavy atoms, and (2) the needed improved performance of DFT exchange-correlation functionals. We have implemented a fully relativistic treatment based on the Dirac Equation into the LANL code RSPt and we have shown that such a treatment is imperative when calculating properties of materials containing actinides and/or lanthanides. The present standard treatment that only includes some of the relativistic terms is not accurate enough and can even give misleading results. Compared to calculations previously considered state of the art, the Dirac treatment gives a substantial change in equilibrium volume predictions for materials with large spin-orbit coupling. For actinide and lanthanide materials, a Dirac treatment is thus a fundamental requirement in any computational investigation, including those for DFT-based EOS construction. For a full capability, a DFT functional capable of describing strongly correlated systems such as actinide materials need to be developed. Using the previously successful subsystem functional scheme developed by Mattsson et.al., we have created such a functional. In this functional the Harmonic Oscillator Gas is providing the necessary reference system for the strong correlation and localization occurring in actinides. Preliminary testing shows that the new Hao-Armiento-Mattsson (HAM) functional gives a trend towards improved results for the crystalline copper oxide test system we have chosen. This test system exhibits the same exchange-correlation physics as the actinide systems do, but without the relativistic effects, giving access to a pure testing ground for functionals. During the work important insights have been gained. An example is that currently available functionals, contrary to common belief, make large errors in so called hybridization regions where electrons from different ions interact and form new states. Together with the new understanding of functional issues, the Dirac implementation into the RSPt code will permit us to gain more fundamental understanding, both quantitatively and qualitatively, of materials of importance for Sandia and the rest of the Nuclear Weapons complex.

Mattsson, Ann Elisabet

2012-01-01T23:59:59.000Z

168

On the Accuracy of van der Waals Inclusive Density-Functional Theory Exchange-Correlation Functionals for Ice at Ambient and High Pressures  

E-Print Network (OSTI)

Density-functional theory (DFT) has been widely used to study water and ice for at least 20 years. However, the reliability of different DFT exchange-correlation (xc) functionals for water remains a matter of considerable debate. This is particularly true in light of the recent development of DFT based methods that account for van der Waals (vdW) dispersion forces. Here, we report a detailed study with several xc functionals (semi-local, hybrid, and vdW inclusive approaches) on ice Ih and six proton ordered phases of ice. Consistent with our previous study [Phys. Rev. Lett. 107, 185701 (2011)] which showed that vdW forces become increasingly important at high pressures, we find here that all vdW inclusive methods considered improve the relative energies and transition pressures of the high-pressure ice phases compared to those obtained with semi-local or hybrid xc functionals. However, we also find that significant discrepancies between experiment and the vdW inclusive approaches remain in the cohesive proper...

Santra, Biswajit; Tkatchenko, Alexandre; Alfč, Dario; Slater, Ben; Michaelides, Angelos; Car, Roberto; Scheffler, Matthias

2013-01-01T23:59:59.000Z

169

On the Accuracy of van der Waals Inclusive Density-Functional Theory Exchange-Correlation Functionals for Ice at Ambient and High Pressures  

E-Print Network (OSTI)

Density-functional theory (DFT) has been widely used to study water and ice for at least 20 years. However, the reliability of different DFT exchange-correlation (xc) functionals for water remains a matter of considerable debate. This is particularly true in light of the recent development of DFT based methods that account for van der Waals (vdW) dispersion forces. Here, we report a detailed study with several xc functionals (semi-local, hybrid, and vdW inclusive approaches) on ice Ih and six proton ordered phases of ice. Consistent with our previous study [Phys. Rev. Lett. 107, 185701 (2011)] which showed that vdW forces become increasingly important at high pressures, we find here that all vdW inclusive methods considered improve the relative energies and transition pressures of the high-pressure ice phases compared to those obtained with semi-local or hybrid xc functionals. However, we also find that significant discrepancies between experiment and the vdW inclusive approaches remain in the cohesive properties of the various phases, causing certain phases to be absent from the phase diagram. Therefore, room for improvement in the description of water at ambient and high pressures remains and we suggest that because of the stern test the high pressure ice phases pose they should be used in future benchmark studies of simulation methods for water.

Biswajit Santra; Ji?í Klimeš; Alexandre Tkatchenko; Dario Alfč; Ben Slater; Angelos Michaelides; Roberto Car; Matthias Scheffler

2013-07-12T23:59:59.000Z

170

An extended SMLD approach for presumed probability density function in flamelet combustion model  

E-Print Network (OSTI)

This paper provides an extension of the standard flamelet progress variable (FPV) approach for turbulent combustion, applying the statistically most likely distribution (SMLD) framework to the joint PDF of the mixture fraction, Z, and the progress variable, C. In this way one does not need to make any assumption about the statistical correlation between Z and C and about the behaviour of the mixture fraction, as required in previous FPV models. In fact, for state-of-the-art models, with the assumption of very-fast-chemistry,Z is widely accepted to behave as a passive scalar characterized by a $\\beta$-distribution function. Instead, the model proposed here, evaluates the most probable joint distribution of Z and C without any assumption on their behaviour and provides an effective tool to verify the adequateness of widely used hypotheses, such as their statistical independence. The model is validated versus three well-known test cases, namely, the Sandia flames. The results are compared with those obtained by ...

Coclite, Alessandro; De Palma, Pietro; Cutrone, Luigi

2013-01-01T23:59:59.000Z

171

Medical Scholars (BS/MD) Program Expectations and Requirements  

E-Print Network (OSTI)

Medical Scholars (BS/MD) Program Expectations and Requirements Undergraduate portion semester GPAs lower than 3.5 will trigger an automatic review by the Medical Scholars Committee of the Medical Scholars Committee, to delay their entry to medical school by one year to broaden their education

Fernandez, Eduardo

172

Accuracy of density functional theory in predicting formation energies of ternary oxides from binary oxides and its implication on phase stability  

E-Print Network (OSTI)

The evaluation of reaction energies between solids using density functional theory (DFT) is of practical importance in many technological fields and paramount in the study of the phase stability of known and predicted ...

Hautier, Geoffroy

173

DOE - Office of Legacy Management -- Bendix Corp Frieze Division - MD 0-01  

Office of Legacy Management (LM)

Bendix Corp Frieze Division - MD Bendix Corp Frieze Division - MD 0-01 FUSRAP Considered Sites Site: BENDIX CORP., FRIEZE DIVISION (MD.0-01 ) Eliminated from further consideration under FUSRAP Designated Name: Not Designated Alternate Name: None Location: Baltimore , Maryland MD.0-01-1 Evaluation Year: 1987 MD.0-01-3 Site Operations: Produced "classified units" believed to be electronics components - no radioactive materials involved. MD.0-01-1 MD.0-01-3 Site Disposition: Eliminated - No radioactive materials handled at this site MD.0-01-3 Radioactive Materials Handled: No Primary Radioactive Materials Handled: None MD.0-01-3 Radiological Survey(s): No Site Status: Eliminated from further consideration under FUSRAP Also see Documents Related to BENDIX CORP., FRIEZE DIVISION

174

DOE - Office of Legacy Management -- Naval Ordnance Laboratory - MD 0-03  

Office of Legacy Management (LM)

Ordnance Laboratory - MD 0-03 Ordnance Laboratory - MD 0-03 FUSRAP Considered Sites Site: NAVAL ORDNANCE LABORATORY (MD.0-03 ) Eliminated from further consideration under FUSRAP - Referred to DOD Designated Name: Not Designated Alternate Name: Naval Ordnance Laboratory - White Oak Location: White Oak Area , Silver Spring , Maryland MD.0-03-1 MD.0-03-2 Evaluation Year: 1987 MD.0-03-2 Site Operations: Research and development - may have involved radioactive materials because the site was identified on a 1955 Accountability Station List. MD.0-03-1 Site Disposition: Eliminated - NRC licensed MD.0-03-2 Radioactive Materials Handled: None Specifically Identified Primary Radioactive Materials Handled: None specifically indicated Radiological Survey(s): None Indicated Site Status: Eliminated from further consideration under FUSRAP - Referred to DOD MD.0-03-2

175

Spectroscopic studies beyond N = 152 neutron gap : decay of {sup 255 ovr sub 101}Md and {sup 256 ovr sub 101}Md.  

Science Conference Proceedings (OSTI)

The isotopes {sup 255}Md and {sup 256}Md were produced by the irradiation of {sup 253}Es with 35-45 MeV {alpha} particles by ({alpha},n) and ({alpha},2n) reactions and were removed from the target by a helium jet system. {alpha}, {gamma}, and {alpha}-{gamma} coincidence spectra were measured with Si and Ge(Li) detectors. From the EC decays of {sup 255}Md and {sup 256}Md, levels in {sup 255}Fm and {sup 256}Fm were deduced. Favored {alpha} decay of {sup 255}Md was found to populate the 7/2{sup -}[514] single-particle state in {sup 251}Es, thus establishing the 7/2{sup -}[514] as the {sup 255}Md ground state. Several {gamma} rays were observed in the {sub 256}Md {alpha}-{gamma} coincidence spectrum. {sup 256}Fm is the heaviest nucleus in which excited intrinsic states have been identified.

Ahmad, I.; Chasman, R. R.; Fields, P. R.

2000-01-01T23:59:59.000Z

176

Spectroscopic studies beyond the N=152 neutron gap: Decay of {sub 101}{sup 255}Md and {sub 101}{sup 256}Md  

Science Conference Proceedings (OSTI)

The isotopes {sup 255}Md and {sup 256}Md were produced by the irradiation of {sup 253}Es with 35-45 MeV {alpha} particles by ({alpha},n) and ({alpha},2n) reactions and were removed from the target by a helium jet system. {alpha}, {gamma}, and {alpha}-{gamma} coincidence spectra were measured with Si and Ge(Li) detectors. From the EC decays of {sup 255}Md and {sup 256}Md, levels in {sup 255}Fm and {sup 256}Fm were deduced. Favored {alpha} decay of {sup 255}Md was found to populate the 7/2{sup -}[514] single-particle state in {sup 251}Es, thus establishing the 7/2{sup -}[514] as the {sup 255}Md ground state. Several {gamma} rays were observed in the {sup 256}Md {alpha}-{gamma} coincidence spectrum. {sup 256}Fm is the heaviest nucleus in which excited intrinsic states have been identified. (c) 2000 The American Physical Society.

Ahmad, I. [Argonne National Laboratory, Argonne, Illinois 60439 (United States); Chasman, R. R. [Argonne National Laboratory, Argonne, Illinois 60439 (United States); Fields, P. R. [Argonne National Laboratory, Argonne, Illinois 60439 (United States)

2000-04-01T23:59:59.000Z

177

A First Principles Density-Functional Calculation of the Electronic and Vibrational Structure of the Key Melanin Monomers  

E-Print Network (OSTI)

We report first principles density functional calculations for hydroquinone (HQ), indolequinone (IQ) and semiquinone (SQ). These molecules are believed to be the basic building blocks of the eumelanins, a class of bio-macromolecules with important biological functions (including photoprotection) and with potential for certain bioengineering applications. We have used the DeltaSCF (difference of self consistent fields) method to study the energy gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), Delta_HL. We show that Delta_HL is similar in IQ and SQ but approximately twice as large in HQ. This may have important implications for our understanding of the observed broad band optical absorption of the eumelanins. The possibility of using this difference in Delta_HL to molecularly engineer the electronic properties of eumelanins is discussed. We calculate the infrared and Raman spectra of the three redox forms from first principles. Each of the molecules have significantly different infrared and Raman signatures, and so these spectra could be used in situ to non-destructively identify the monomeric content of macromolecules. It is hoped that this may be a helpful analytical tool in determining the structure of eumelanin macromolecules and hence in helping to determine the structure-property-function relationships that control the behaviour of the eumelanins.

B. J. Powell; T. Baruah; N. Bernstein; K. Brake; Ross H. McKenzie; P. Meredith; M. R. Pederson

2004-01-23T23:59:59.000Z

178

Helium under high pressure: A comparative study of all-electron and pseudopotential methods within density functional theory  

E-Print Network (OSTI)

We have calculated the ground state electronic structure of He under pressure from 0 to 1500 GPa using both all-electron full-potential and pseudopotential methods based on the density functional theory (DFT). We find that throughout this pressure range, pseudopotentials yield essentially the same energy-volume curve for all of bcc, fcc, and hcp configurations as does the full-potential method, a strong indication that pseudopotential approximation works well for He both as the common element in some giant planets and as detrimental impurities in fusion reactor materials. The hcp lattice is always the most stable structure and bcc the least stable one. Since the energy preference of hcp over fcc and bcc is within 0.01 eV below 100 GPa and about 0.1 eV at 1500 GPa, on the same order of the error bar in local or semi-local density approximations in DFT, phase transitions can only be discussed with more precise description of electron correlation in Quantum Monte Carlo or DFT-based GW methods.

Xiao, W; Geng, W T

2012-01-01T23:59:59.000Z

179

Quantifying the importance of orbital over spin correlations in delta-Pu within density-functional theory  

SciTech Connect

Spin and orbital and electron correlations are known to be important when treating the high-temperature {delta} phase of plutonium within the framework of density-functional theory (DFT). One of the more successful attempts to model {delta}-Pu within this approach has included condensed-matter generalizations of Hund's three rules for atoms, i.e., spin polarization, orbital polarization, and spin-orbit coupling. Here they perform a quantitative analysis of these interactions relative rank for the bonding and electronic structure in {delta}-Pu within the DFT model. The result is somewhat surprising in that spin-orbit coupling and orbital polarization are far more important than spin polarization for a realistic description of {delta}-Pu. They show that these orbital correlations on their own, without any formation of magnetic spin moments, can account for the low atomic density of the {delta} phase with a reasonable equation-of-state. In addition, this unambiguously non-magnetic (NM) treatment produces a one-electron spectra with resonances close to the Fermi level consistent with experimental valence band photoemission spectra.

Soderlind, P; Wolfer, W

2007-07-27T23:59:59.000Z

180

The tensor part of the Skyrme energy density functional. III. Time-odd terms at high spin  

E-Print Network (OSTI)

This article extends previous studies on the effect of tensor terms in the Skyrme energy density functional by breaking of time-reversal invariance. We have systematically probed the impact of tensor terms on properties of superdeformed rotational bands calculated within the cranked Hartree-Fock-Bogoliubov approach for different parameterizations covering a wide range of values for the isoscalar and isovector tensor coupling constants. We analyze in detail the contribution of the tensor terms to the energies and dynamical moments of inertia and study their impact on quasi-particle spectra. Special attention is devoted to the time-odd tensor terms, the effect of variations of their coupling constants and finite-size instabilities.

V. Hellemans; P. -H. Heenen; M. Bender

2011-12-15T23:59:59.000Z

Note: This page contains sample records for the topic "md density functional" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
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181

"Kohn-Shamification" of the classical density-functional theory of inhomogeneous polar molecular liquids with application to liquid hydrogen chloride  

E-Print Network (OSTI)

The Gordian knot of density-functional theories for classical molecular liquids remains finding an accurate free-energy functional in terms of the densities of the atomic sites of the molecules. Following Kohn and Sham, we show how to solve this problem by considering noninteracting molecules in a set of effective potentials. This shift in perspective leads to an accurate and computationally tractable description in terms of simple three-dimensional functions. We also treat both the linear- and saturation- dielectric responses of polar systems, presenting liquid hydrogen chloride as a case study.

Johannes Lischner; T. A. Arias

2008-06-27T23:59:59.000Z

182

Comparative Study of Selected Wave Function and Density Functional Methods for Noncovalent Interaction Energy Calculations Using the Extended S22 Data Set  

Science Conference Proceedings (OSTI)

In this paper, an extension of the S22 data set of Jurecka et al. (Jure?ka, P.; Šponer, J.; ?erný, J.; Hobza, P. Phys. Chem. Chem. Phys. 2006, 8, 1985.), the data set of benchmark CCSD(T)/CBS interaction energies of twenty-two noncovalent complexes in equilibrium geometries, is presented. The S22 data set has been extended by including the stretched (one shortened and three elongated) complex geometries of the S22 data set along the main noncovalent interaction coordinate. The goal of this work is to assess the accuracy of the popular wave function methods (MP2-, MP3- and, CCSD-based) and density functional methods (with and without empirical correction for the dispersion energy) for noncovalent complexes based on a statistical evaluation not only in equilibrium, but also in nonequilibrium geometries. The results obtained in this work provide information on whether an accurate and balanced description of the different interaction types and complex geometry distortions can be expected from the tested methods. This information has an important implication in the calculation of large molecular complexes, where the number of distant interacting molecular fragments, often in far from equilibrium geometries, increases rapidly with the system size. The best performing WFT methods were found to be the SCS-CCSD (spin-component scaled CCSD, according to Takatani, T.; Hohenstein, E. G.; Sherrill, C. D. J. Chem. Phys. 2008, 128, 124111), MP2C (dispersion-corrected MP2, according to Hesselmann, A. J. Chem. Phys. 2008, 128, 144112), and MP2.5 (scaled MP3, according to Pito?ák, M.; Neogrády, P.; ?erný, J.; Grimme, S.; Hobza, P. ChemPhysChem 2009, 10, 282.). Since none of the DFT methods fulfilled the required statistical criteria proposed in this work, they cannot be generally recommended for large-scale calculations. The DFT methods still have the potential to deliver accurate results for large molecules, but most likely on the basis of an error cancellation.

Grafova, Lucie; Pitonak, Michal; Rezac, Jan; Hobza, Pavel

2010-08-10T23:59:59.000Z

183

E Matrix' for the Loewdin alpha function, expanded in a Taylor series: an analytic treatment of molecular charge density near the origin  

Science Conference Proceedings (OSTI)

A displaced STO can be expanded in spherical harmonics with the coefficient function or Loewdin or functions characterized by a C matrix. These or functions themselves may be expanded in a Taylor series that is characterized by its own E Matrix. This expansion is necessary for the representation of the or function by a power series and for its evaluation about the origin. As an application, the power series for the molecular charge density in the vicinity of the center of a model diatomic molecule. The analytic approach is general and yields excellent results.

Jones, H.W.; Bussery, B.; Weatherford, C.A.

1987-01-01T23:59:59.000Z

184

Correcting Density Functional Theory for Accurate Predictions of Compound Enthalpies of Formation: Fitted Elemental-Phase Reference Energies  

Science Conference Proceedings (OSTI)

Despite the great success that theoretical approaches based on density functional theory have in describing properties of solid compounds, accurate predictions of the enthalpies of formation ({Delta}H{sub f}) of insulating and semiconducting solids still remain a challenge. This is mainly due to incomplete error cancellation when computing the total energy differences between the compound total energy and the total energies of its elemental constituents. In this paper we present an approach based on GGA + U calculations, including the spin-orbit coupling, which involves fitted elemental-phase reference energies (FERE) and which significantly improves the error cancellation resulting in accurate values for the compound enthalpies of formation. We use an extensive set of 252 binary compounds with measured {Delta}H{sub f} values (pnictides, chalcogenides, and halides) to obtain FERE energies and show that after the fitting, the 252 enthalpies of formation are reproduced with the mean absolute error MAE = 0.054 eV/atom instead of MAE {approx} 0.250 eV/atom resulting from pure GGA calculations. When applied to a set of 55 ternary compounds that were not part of the fitting set the FERE method reproduces their enthalpies of formation with MAE = 0.048 eV/atom. Furthermore, we find that contributions to the total energy differences coming from the spin-orbit coupling can be, to a good approximation, separated into purely atomic contributions which do not affect {Delta}H{sub f}. The FERE method, hence, represents a simple and general approach, as it is computationally equivalent to the cost of pure GGA calculations and applies to virtually all insulating and semiconducting compounds, for predicting compound {Delta}H{sub f} values with chemical accuracy. We also show that by providing accurate {Delta}H{sub f} the FERE approach can be applied for accurate predictions of the compound thermodynamic stability or for predictions of Li-ion battery voltages.

Stevanovic, V.; Lany, S.; Zhang, X.; Zunger, A.

2012-03-15T23:59:59.000Z

185

A density functional theory study of the oxidation of methanol to formaldehyde over vanadia supported on silica, titania, and zirconia  

DOE Green Energy (OSTI)

Density functional theory was used to investigate the mechanism and kinetics of methanol oxidation to formaldehyde over vanadia supported on silica, titania, and zirconia. The catalytically active site was modeled as an isolated VO{sub 4} unit attached to the support. The calculated geometry and vibrational frequencies of the active site are in good agreement with experimental measurements both for model compounds and oxide-supported vanadia. Methanol adsorption is found to occur preferentially with the rupture of a V-O-M bond (M = Si, Ti, Zr) and with preferential attachment of a methoxy group to V. The vibrational frequencies of the methoxy group are in good agreement with those observed experimentally as are the calculated isobars. The formation of formaldehyde is assumed to occur via the transfer of an H atom of a methoxy group to the O atom of the V=O group. The activation energy for this process is found to be in the range of 199-214 kJ/mol and apparent activation energies for the overall oxidation of methanol to formaldehyde are predicted to lie in the range of 112-123 kJ/mol, which is significantly higher than that found experimentally. Moreover, the predicted turnover frequency (TOF) for methanol oxidation is found to be essentially independent of support composition, whereas experiments show that the TOF is 10{sup 3} greater for titania- and zirconia-supported vanadia than for silica-supported vanadia. Based on these findings, it is proposed that the formation of formaldehyde from methoxy groups may require pairs of adjacent VO{sub 4} groups or V{sub 2}O{sub 7} dimer structures.

Khaliullin, Rustam Z.; Bell, Alexis T.

2002-09-05T23:59:59.000Z

186

The least type of an entire function of order {rho} element of (0,1) having positive zeros with prescribed averaged densities  

Science Conference Proceedings (OSTI)

The problem of the least type of entire functions of order {rho} element of (0,1) all of whose zeros lie on the same ray and have the prescribed upper and lower mean {rho}-densities is solved. A complete investigation of the value of the extremal type is carried out, including a description of its asymptotic behaviour. Bibliography: 14 titles.

Braichev, Georgii G [Moscow State Pedagogical University, Moscow (Russian Federation)

2012-07-31T23:59:59.000Z

187

The 2 1 reconstruction of the rutile TiO2(011) surface: A combined density functional theory, X-ray diffraction, and scanning  

E-Print Network (OSTI)

t An extensive search for possible structural models of the (2 Ă? 1)-reconstructed rutile TiO2(011) surface was carried out by means of density functional theory (DFT) calculations. A number of models were iden- tified that have much lower surface energies than the previously-proposed `titanyl' and `microfaceting' models

Diebold, Ulrike

188

Accurate dipole polarizabilities for water clusters n=2-12 at the coupled-cluster level of theory and benchmarking of various density functionals.  

Science Conference Proceedings (OSTI)

The static dipole polarizabilities of water clusters (2 {le} N {le} 12) are determined at the coupled-cluster level of theory (CCSD). For the dipole polarizability of the water monomer it was determined that the role of the basis set is more important than that of electron correlation and that the basis set augmentation converges with two sets of diffuse functions. The CCSD results are used to benchmark a variety of density functionals while the performance of several families of basis sets (Dunning, Pople, and Sadlej) in producing accurate values for the polarizabilities was also examined. The Sadlej family of basis sets was found to produce accurate results when compared to the ones obtained with the much larger Dunning basis sets. It was furthermore determined that the PBE0 density functional with the aug-cc-pVDZ basis set produces overall remarkably accurate polarizabilities at a moderate computational cost.

Hammond, J.; Govind, N.; Kowalski, K.; Autschbach, J.; Xantheas, S.; PNNL; Univ. of Buffalo

2009-12-07T23:59:59.000Z

189

Oral Histories: Oncologist Helen Vodopick, M.D.  

NLE Websites -- All DOE Office Websites (Extended Search)

2 2 HUMAN RADIATION STUDIES: REMEMBERING THE EARLY YEARS Oral History of Oncologist Helen Vodopick, M.D. Conducted December 28, 1994 United States Department of Energy Office of Human Radiation Experiments August 1995 CONTENTS Foreword Short Biography Academic Fellowship at Oak Ridge Institute for Nuclear Studies (ORINS), 1960 Appointment to the Staff at ORINS Medical Division The Medium-Exposure-Rate Total Body Irradiator (METBI) ORINS Radioisotope Tracer Studies Participation by Regional Universities at Oak Ridge Associated Universities (ORAU) Treatment of Cancer Patients with the METBI Introduction of Immunotherapy Radiation Treatment for Leukemia Patients Bone Marrow Treatment of Leukemia Low-Exposure-Rate Total Body Irradiator (LETBI) Treatment of Radiation Accident Victims at ORAU

190

Sedimentation of a two-dimensional colloidal mixture exhibiting liquid-liquid and gas-liquid phase separation: a dynamical density functional theory study  

E-Print Network (OSTI)

We present dynamical density functional theory results for the time evolution of the density distribution of a sedimenting model two-dimensional binary mixture of colloids. The interplay between the bulk phase behaviour of the mixture, its interfacial properties at the confining walls, and the gravitational field gives rise to a rich variety of equilibrium and non-equilibrium morphologies. In the fluid state, the system exhibits both liquid-liquid and gas-liquid phase separation. As the system sediments, the phase separation significantly affects the dynamics and we explore situations where the final state is a coexistence of up to three different phases. Solving the dynamical equations in two-dimensions, we find that in certain situations the final density profiles of the two species have a symmetry that is different from that of the external potentials, which is perhaps surprising, given the statistical mechanics origin of the theory. The paper concludes with a discussion on this.

Alexandr Malijevsky; Andrew J. Archer

2013-09-17T23:59:59.000Z

191

Soham Al Snih Al Snih, MD., PhD. Curriculum Vitae CURRICULUM VITAE  

E-Print Network (OSTI)

Soham Al Snih Al Snih, MD., PhD. Curriculum Vitae 1 CURRICULUM VITAE NAME: Soham Al Snih Al Snih, M at the Sealy Center on Aging, University of Texas Medical Branch, Galveston, TX. #12;Soham Al Snih Al Snih, MD arthritis. B. Grant Support Current Grant Support: 1R03 AG029959-01A2 (Al Snih ­PI) Period: 06

Wood, James B.

192

EA-1942: Cove Point Liquefaction Project, Lusby, MD | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

2: Cove Point Liquefaction Project, Lusby, MD 2: Cove Point Liquefaction Project, Lusby, MD EA-1942: Cove Point Liquefaction Project, Lusby, MD SUMMARY The Federal Energy Regulatory Commission (FERC) is preparing, with DOE as a cooperating agency, an EA, to analyze the potential environmental impacts of a proposal to add natural gas liquefaction and exportation capabilities to an existing Cove Point LNG Terminal located on the Chesapeake Bay in Lusby, Maryland. PUBLIC COMMENT OPPORTUNITIES None available at this time. DOCUMENTS AVAILABLE FOR DOWNLOAD September 28, 2012 EA-1942: Notice of Intent to Prepare an Environmental Assessment Cove Point Liquefaction Project, Lusby, MD September 24, 2012 EA-1942: Notice of Intent of to Prepare an Environmental Assessment Cove Point Liquefaction Project, Lusby, MD

193

Numerical simulation of clarifier-thickener units treating ideal suspensions with a flux density function having two inflection points  

Science Conference Proceedings (OSTI)

We consider a nonconvex conservation law modelling the settling of particles in ideal clarifier-thickener units. The flux function of this conservation law has an explicit spatial dependence that is discontinuous. Previous works by two of the authors, ... Keywords: Clarifier-thickener, Conservation law, Continuous sedimentation, Discontinuous flux, Finite difference method, Numerical simulation

R. BüRger; F. Concha; K. H. Karlsen; A. NarváEz

2006-08-01T23:59:59.000Z

194

Linear-response and real-time time-dependent density functional theory studies of core-level near-edge x-ray absorption  

Science Conference Proceedings (OSTI)

We discuss our implementation and application of time-dependent density functional theory (TDDFT) to core-level near-edge absorption spectroscopy, using both linear-response (LR) and real-time (RT) approaches. We briefly describe our restricted window TDDFT (REWTDDFT) approach for core excitations which has also been reported by others groups. This is followed by a detailed discussion of real-time TDDFT techniques tailored to core excitations, including obtaining spectral information through delta-function excitation, post-processing time-dependent signals, and resonant excitation through quasi-monochromatic excitation. We present results for the oxygen K-edge of water and carbon dioxide; the carbon K-edge of carbon dioxide; the ruthenium L3-edge for the hexaamminerutheium(III) ion, including scalar relativistic corrections via the zeroth order regular approximation (ZORA); and the carbon and fluorine K-edges for a series of fluorobenzenes. In all cases, the calculated spectra are found to be in good agreement with experiment, requiring only a uniform shift on the order of a few percent. Real-time TDDFT visualization of excited state charge densities are used to visually examine the nature of each excitation, which gives insight into the effects of atoms bound to the absorbing center.

Lopata, Kenneth A.; Van Kuiken, Benjamin E.; Khalil, Munira; Govind, Niranjan

2012-09-03T23:59:59.000Z

195

Kinetics of the sulfur oxidation on palladium: A combined in situ x-ray photoelectron spectroscopy and density-functional study  

Science Conference Proceedings (OSTI)

We studied the reaction kinetics of sulfur oxidation on the Pd(100) surface by in situ high resolution x-ray photoelectron spectroscopy and ab initio density functional calculations. Isothermal oxidation experiments were performed between 400 and 500 K for small amounts ({approx}0.02 ML) of preadsorbed sulfur, with oxygen in large excess. The main stable reaction intermediate found on the surface is SO{sub 4}, with SO{sub 2} and SO{sub 3} being only present in minor amounts. Density-functional calculations depict a reaction energy profile, which explains the sequential formation of SO{sub 2}, SO{sub 3}, and eventually SO{sub 4}, also highlighting that the in-plane formation of SO from S and O adatoms is the rate limiting step. From the experiments we determined the activation energy of the rate limiting step to be 85 {+-} 6 kJ mol{sup -1} by Arrhenius analysis, matching the calculated endothermicity of the SO formation.

Gotterbarm, Karin; Hoefert, Oliver; Lorenz, Michael P. A.; Streber, Regine; Papp, Christian [Lehrstuhl fuer Physikalische Chemie II, Universitaet Erlangen-Nuernberg, Egerlandstr. 3, 91058 Erlangen (Germany); Luckas, Nicola; Vines, Francesc [Lehrstuhl fuer Theoretische Chemie, Universitaet Erlangen-Nuernberg, Egerlandstr. 3, 91058 Erlangen (Germany); Steinrueck, Hans-Peter [Lehrstuhl fuer Physikalische Chemie II, Universitaet Erlangen-Nuernberg, Egerlandstr. 3, 91058 Erlangen (Germany); Erlangen Catalysis Resource Center (ECRC), Universitaet Erlangen-Nuernberg, Egerlandstr. 3, 91058 Erlangen (Germany); Interdisciplinary Center for Interface Controlled Processes, Egerlandstr. 3, 91058 Erlangen (Germany); Goerling, Andreas [Lehrstuhl fuer Theoretische Chemie, Universitaet Erlangen-Nuernberg, Egerlandstr. 3, 91058 Erlangen (Germany); Interdisciplinary Center for Interface Controlled Processes, Egerlandstr. 3, 91058 Erlangen (Germany)

2012-03-07T23:59:59.000Z

196

BERAC Meeting, October 6-7, 2011, Rockville, MD| U.S. DOE Office of Science  

Office of Science (SC) Website

Meeting, October 6-7, 2011, Rockville, MD Meeting, October 6-7, 2011, Rockville, MD Biological and Environmental Research Advisory Committee (BERAC) BERAC Home Meetings BERAC Minutes BERAC Minutes Archive Members Charges/Reports Charter .pdf file (40KB) BER Committees of Visitors BER Home Meetings BERAC Meeting, October 6-7, 2011, Rockville, MD Print Text Size: A A A RSS Feeds FeedbackShare Page BERAC Meeting October 6-7, 2011 Rockville, MD Agenda .docx file (13KB) Presentations Sharlene Weatherwax, State of BER Report .pptx file (2.0MB) Gary Geernaert, Climate and Environmental Sciences Division Update .pptx file (24.0MB) Todd Anderson, Biological Systems Science Division Update .pptx file (8.0MB) Susan Hubbard, Science Talk - Geophysical Signatures of Subsurface Microbially-Mediated Processes: Toward Quantification of In-Situ Ecosystem

197

BERAC Meeting October 16, 2006 North Bethesda, MD | U.S. DOE Office of  

Office of Science (SC) Website

October 16, 2006 North Bethesda, MD October 16, 2006 North Bethesda, MD Biological and Environmental Research Advisory Committee (BERAC) BERAC Home Meetings BERAC Minutes BERAC Minutes Archive Members Charges/Reports Charter .pdf file (40KB) BER Committees of Visitors BER Home Meetings BERAC Meeting October 16, 2006 North Bethesda, MD Print Text Size: A A A RSS Feeds FeedbackShare Page BERAC Meeting October 16, 2006 North Bethesda, MD Agenda .pdf file (8KB) Presentations Jerry Elwood .ppt file (4.1MB), State of BER James Ehleringer .ppt file (6.7MB), Report on BERAC Review of FACE Experiments David Kingsbury .ppt file (10.4MB), CAMERA-Metagenomics meets the Cyberinfrastructure Chris Somerville .ppt file (59KB), Life Sciences PART Measure Progress Report Joyce Penner .ppt file (116KB), Climate Change Science PART Measure

198

BERAC Meeting February 18 - 19, 2009 North Bethesda, MD | U.S. DOE Office  

Office of Science (SC) Website

18 - 19, 2009 North Bethesda, MD 18 - 19, 2009 North Bethesda, MD Biological and Environmental Research Advisory Committee (BERAC) BERAC Home Meetings BERAC Minutes BERAC Minutes Archive Members Charges/Reports Charter .pdf file (40KB) BER Committees of Visitors BER Home Meetings BERAC Meeting February 18 - 19, 2009 North Bethesda, MD Print Text Size: A A A RSS Feeds FeedbackShare Page Biological and Environmental Research Advisory Committee Meeting February 18-19, 2009 North Bethesda, MD Meeting Agenda .pdf file (9KB) Presentations Anna Palmisano .ppt file (11.7MB), State of BER Sharlene Weatherwax .ppt file (8.7MB), Biological Systems Science Division Update Wanda Ferrell .ppt file (16.9MB), Climate and Environmental Sciences Division Update Jeff Amthor, Report on the Climate Change Research Strategic Plan

199

BERAC Meeting February 23-24, 2010 Gaithersburg, MD | U.S. DOE Office of  

Office of Science (SC) Website

February 23-24, 2010 Gaithersburg, MD February 23-24, 2010 Gaithersburg, MD Biological and Environmental Research Advisory Committee (BERAC) BERAC Home Meetings BERAC Minutes BERAC Minutes Archive Members Charges/Reports Charter .pdf file (40KB) BER Committees of Visitors BER Home Meetings BERAC Meeting February 23-24, 2010 Gaithersburg, MD Print Text Size: A A A RSS Feeds FeedbackShare Page BERAC Meeting February 23-24,2010 Gaithersburg MD Agenda .pdf file (8KB) Presentations Patricia Dehmer .ppt file (7.4MB), News from the Office of Science Anna Palmisano .ppt file (18.0MB), State of BER Jeff Marqusee .ppt file (5.0MB), SERDP & ESTCP Phil Robertson .pdf file (3.1MB), Bioenergy & Sustainability (pdf format) Wanda Ferrell .ppt file (5.1MB), Climate and Environmental Sciences Division Update

200

BERAC Meeting September 1-2, 2009 Gaithersburg, MD | U.S. DOE Office of  

Office of Science (SC) Website

-2, 2009 Gaithersburg, MD -2, 2009 Gaithersburg, MD Biological and Environmental Research Advisory Committee (BERAC) BERAC Home Meetings BERAC Minutes BERAC Minutes Archive Members Charges/Reports Charter .pdf file (40KB) BER Committees of Visitors BER Home Meetings BERAC Meeting September 1-2, 2009 Gaithersburg, MD Print Text Size: A A A RSS Feeds FeedbackShare Page BERAC Meeting September 1-2, 2009 Gaithersburg, MD Agenda .pdf file (8KB) Presentations Patricia Dehmer .ppt file (25.0MB), News from the Office of Science Anna Palmisano .pptx file (6.6MB), State of BER Barbara Alving, NIH .ppt file (6.6MB), Connecting the Nation's Researchers, Patients and Communities: Next Steps Horst Simon .pdf file (2.6MB), Future Trends in Computing Sharlene Weatherwax .pdf file (928KB), Biological Systems Science

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


201

BERAC Meeting May 19-20, 2008 Hilton Hotel Gaithersburg, MD | U.S. DOE  

Office of Science (SC) Website

9-20, 2008 Hilton Hotel Gaithersburg, MD 9-20, 2008 Hilton Hotel Gaithersburg, MD Biological and Environmental Research Advisory Committee (BERAC) BERAC Home Meetings BERAC Minutes BERAC Minutes Archive Members Charges/Reports Charter .pdf file (40KB) BER Committees of Visitors BER Home Meetings BERAC Meeting May 19-20, 2008 Hilton Hotel Gaithersburg, MD Print Text Size: A A A RSS Feeds FeedbackShare Page BERAC Meeting May 19-20, 2008 Hilton Hotel Gaithersburg, MD Agenda .pdf file (17KB) Presentations Mike Hochella .ppt file (388KB), Environmental Remediation Sciences Division Committee of Visitors Report Jim Adelstein .ppt file (1.1MB), Report on the Low Dose Radiation Research Program Himadri Pakrasi .ppt file (22.3MB), Science Talk, Membrane Biology Grand Challenge Jeff Amthor .ppt file (11.7MB), Update on BER Program for Ecosystems

202

BERAC Meeting, June 6-7, 2012 Gaithersburg, MD| U.S. DOE Office of Science  

Office of Science (SC) Website

June 6-7, 2012 Gaithersburg, MD June 6-7, 2012 Gaithersburg, MD Biological and Environmental Research Advisory Committee (BERAC) BERAC Home Meetings BERAC Minutes BERAC Minutes Archive Members Charges/Reports Charter .pdf file (40KB) BER Committees of Visitors BER Home Meetings BERAC Meeting, June 6-7, 2012 Gaithersburg, MD Print Text Size: A A A RSS Feeds FeedbackShare Page BERAC Meeting June 6-7, 2012 Gaithersburg, MD Agenda .pdf file (424KB) Presentations Sharlene Weatherwax, BER Associate Director State of BER Report .pdf file (482KB) Todd Anderson, Director, Biological Systems Science Division Biological Systems Science Division Update .pdf file (1.9MB) Gary Geernaert, Director, Climate and Environmental Sciences Division Climate and Environmental Sciences Division Update .pdf file (1.6MB) Jonathan Petters,

203

BERAC Meeting, February 21-22, 2013, Rockville, MD | U.S. DOE Office of  

Office of Science (SC) Website

February 21-22, 2013 BERAC Rockville, MD February 21-22, 2013 BERAC Rockville, MD Biological and Environmental Research Advisory Committee (BERAC) BERAC Home Meetings BERAC Minutes BERAC Minutes Archive Members Charges/Reports Charter .pdf file (40KB) BER Committees of Visitors BER Home Meetings February 21-22, 2013 BERAC Rockville, MD Print Text Size: A A A RSS Feeds FeedbackShare Page BERAC Meeting, February 21-22, 2013, Rockville, MD Agenda .pdf file (10KB) Presentations: Sharlene Weatherwax .pdf file (1.9MB) - Office of Biological and Environmental Research Update Todd Anderson .pdf file (1.7MB) - Biological Systems Science Division Update Gary Geernaert .pdf file (2.3MB) - Climate and Environmental Sciences Division Update Judy Wall .pdf file (3.5MB) - The Genetic Basis for Bacterial Mercury Methylation

204

BERAC Meeting May 14-15, 2007 North Bethesda, MD | U.S. DOE Office of  

Office of Science (SC) Website

4-15, 2007 North Bethesda, MD 4-15, 2007 North Bethesda, MD Biological and Environmental Research Advisory Committee (BERAC) BERAC Home Meetings BERAC Minutes BERAC Minutes Archive Members Charges/Reports Charter .pdf file (40KB) BER Committees of Visitors BER Home Meetings BERAC Meeting May 14-15, 2007 North Bethesda, MD Print Text Size: A A A RSS Feeds FeedbackShare Page BERAC Meeting May 14-15, 2007 North Bethesda, MD Agenda .pdf file (10KB) Presentations Joyce Penner .ppt file (74KB), Report on ARM Facilities Charge William Pizer .pdf file (292KB), Report on Integrated Assessment Charge John Ferrell .ppt file (2.7MB), Report on DOE Energy Efficiency and Renewable Energy Biomass Program Paul Vaska .ppt file (23.6MB), Science Talk, Advances in Instrumentation for Small-Animal PET Imaging Mike Viola .ppt file (2.3MB), State of BER

205

BERAC Meeting September 16-17, 2010 Gaithersburg, MD | U.S. DOE Office of  

Office of Science (SC) Website

6-17, 2010 Gaithersburg, MD 6-17, 2010 Gaithersburg, MD Biological and Environmental Research Advisory Committee (BERAC) BERAC Home Meetings BERAC Minutes BERAC Minutes Archive Members Charges/Reports Charter .pdf file (40KB) BER Committees of Visitors BER Home Meetings BERAC Meeting September 16-17, 2010 Gaithersburg, MD Print Text Size: A A A RSS Feeds FeedbackShare Page BERAC Meeting September 16-17, 2010 Gaithersburg, MD Agenda .pdf file (8KB) Presentations Anna Palmisano .pptx file (6.5MB), State of BER Judy Wall .pptx file (904KB), CESD COV Report Gary Sayler .ppt file (65.0MB), Science Lecture, "From Microbes to Man: Environmental Biosensing with Bacterial Bioluminescence" Gary Geernaert .pptx file (4.5MB), Climate and Environmental Sciences Division Update Sharlene Weatherwax .pptx file (5.6MB), Biological Systems Science

206

Price of Cove Point, MD Natural Gas LNG Imports from Algeria...  

Gasoline and Diesel Fuel Update (EIA)

Algeria (Dollars per Thousand Cubic Feet) Price of Cove Point, MD Natural Gas LNG Imports from Algeria (Dollars per Thousand Cubic Feet) Decade Year-0 Year-1 Year-2 Year-3 Year-4...

207

Price of Cove Point, MD Natural Gas LNG Total Imports (Dollars...  

Gasoline and Diesel Fuel Update (EIA)

Total Imports (Dollars per Thousand Cubic Feet) Price of Cove Point, MD Natural Gas LNG Total Imports (Dollars per Thousand Cubic Feet) Decade Year-0 Year-1 Year-2 Year-3 Year-4...

208

Price of Cove Point, MD Natural Gas LNG Imports from Egypt (Nominal...  

U.S. Energy Information Administration (EIA) Indexed Site

Egypt (Nominal Dollars per Thousand Cubic Feet) Price of Cove Point, MD Natural Gas LNG Imports from Egypt (Nominal Dollars per Thousand Cubic Feet) Decade Year-0 Year-1 Year-2...

209

LDRD Final Report (08-ERD-037): Important Modes to Drive Protein MD Simulations to the Next Conformational Level  

SciTech Connect

Every action in biology is performed by dynamic proteins that convert between multiple states in order to engage their functions. Often binding to various ligands is essential for the rates of desired transitions to be enhanced. The goal of computational biology is to study these transitions and discover the different states to fully understand the protein's normal and diseased function, design drugs to target/bias specific states, and understand all of the interactions in between. We have developed a new methodology that is capable of calculating the absolute free energy of proteins while taking into account all the interactions with the solvent molecules. The efficiency of the new scheme is an order of magnitude greater than any existing technique. This method is now implemented in the massively parallel popular MD program package NAMD. This now makes it possible to calculate the relative stability of different conformational states of biological macromolecules as well as their binding free energies to various ligands.

Sadigh, B

2011-04-07T23:59:59.000Z

210

SIZES, HALF-MASS DENSITIES, AND MASS FUNCTIONS OF STAR CLUSTERS IN THE MERGER REMNANT NGC 1316: CLUES TO THE FATE OF SECOND-GENERATION GLOBULAR CLUSTERS  

SciTech Connect

We study mass functions of globular clusters derived from Hubble Space Telescope/Advanced Camera for Surveys images of the early-type merger remnant galaxy NGC 1316, which hosts a significant population of metal-rich globular clusters of intermediate age ({approx}3 Gyr). For the old, metal-poor ({sup b}lue{sup )} clusters, the peak mass of the mass function M{sub p} increases with internal half-mass density {rho}{sub h} as M{sub p}{proportional_to}{rho}{sub h}{sup 0.44}, whereas it stays approximately constant with galactocentric distance R{sub gal}. The mass functions of these clusters are consistent with a simple scenario in which they formed with a Schechter initial mass function and evolved subsequently by internal two-body relaxation. For the intermediate-age population of metal-rich ({sup r}ed{sup )} clusters, the faint end of the previously reported power-law luminosity function of the clusters with R{sub gal} > 9 kpc is due to many of those clusters having radii larger than the theoretical maximum value imposed by the tidal field of NGC 1316 at their R{sub gal}. This renders disruption by two-body relaxation ineffective. Only a few such diffuse clusters are found in the inner regions of NGC 1316. Completeness tests indicate that this is a physical effect. Using comparisons with star clusters in other galaxies and cluster disruption calculations using published models, we hypothesize that most red clusters in the low-{rho}{sub h} tail of the initial distribution have already been destroyed in the inner regions of NGC 1316 by tidal shocking, and that several remaining low-{rho}{sub h} clusters will evolve dynamically to become similar to 'faint fuzzies' that exist in several lenticular galaxies. Finally, we discuss the nature of diffuse red clusters in early-type galaxies.

Goudfrooij, Paul, E-mail: goudfroo@stsci.edu [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

2012-05-10T23:59:59.000Z

211

Stability of critical bubble in stretched fluid of square-gradient density-functional model with triple-parabolic free energy  

E-Print Network (OSTI)

The square-gradient density-functional model with triple-parabolic free energy, that was used previously to study the homogeneous bubble nucleation [J. Chem. Phys. 129, 104508 (2008)], is used to study the stability of the critical bubble nucleated within the bulk under-saturated stretched fluid. The stability of the bubble is studied by solving the Schr\\"odinger equation for the fluctuation. The negative eigenvalue corresponds to the unstable growing mode of the fluctuation. Our results show that there is only one negative eigenvalue whose eigenfunction represents the fluctuation that corresponds to the isotropically growing or shrinking nucleus. In particular, this negative eigenvalue survives up to the spinodal point. Therefore the critical bubble is not fractal or ramified near the spinodal.

Masao Iwamatsu; Yutaka Okabe

2010-06-11T23:59:59.000Z

212

Density functional theory studies on theelectronic, structural, phonon dynamicaland thermo-stability properties of bicarbonates MHCO3, M D Li, Na, K  

Science Conference Proceedings (OSTI)

The structural, electronic, phonon dispersion and thermodynamic properties of MHCO3 (M D Li, Na, K) solids were investigated using density functional theory. The calculated bulk properties for both their ambient and the high-pressure phases are in good agreement with available experimental measurements. Solid phase LiHCO3 has not yet been observed experimentally. We have predicted several possible crystal structures for LiHCO3 using crystallographic database searching and prototype electrostatic ground state modeling. Our total energy and phonon free energy .FPH/ calculations predict that LiHCO3 will be stable under suitable conditions of temperature and partial pressures of CO2 and H2O. Our calculations indicate that the HCO􀀀 3 groups in LiHCO3 and NaHCO3 form an infinite chain structure through O#1; #1; #1;H#1; #1; #1;O hydrogen bonds. In contrast, the HCO􀀀 3 anions form dimers, .HCO􀀀 3 /2, connected through double hydrogen bonds in all phases of KHCO3. Based on density functional perturbation theory, the Born effective charge tensor of each atom type was obtained for all phases of the bicarbonates. Their phonon dispersions with the longitudinal optical–transverse optical splitting were also investigated. Based on lattice phonon dynamics study, the infrared spectra and the thermodynamic properties of these bicarbonates were obtained. Over the temperature range 0–900 K, the FPH and the entropies (S) of MHCO3 (M D Li, Na, K) systems vary as FPH.LiHCO3/ > FPH.NaHCO3/ > FPH.KHCO3/ and S.KHCO3/ > S.NaHCO3/ > S.LiHCO3/, respectively, in agreement with the available experimental data. Analysis of the predicted thermodynamics of the CO2 capture reactions indicates that the carbonate/bicarbonate transition reactions for Na and K could be used for CO2 capture technology, in agreement with experiments.

Duan, Yuhua; Zhang, Bo; Sorescu, Dan C.; Johnson, Karl; Majzoub, Eric H; Luebke, David R.

2012-07-01T23:59:59.000Z

213

Assignment of near-edge x-ray absorption fine structure spectra of metalloporphyrins by means of time-dependent density-functional calculations  

Science Conference Proceedings (OSTI)

The C 1s and N 1s near-edge x-ray absorption fine structure (NEXAFS) spectra of three prototype tetraphenyl porphyrin (TPP) molecules are discussed in the framework of a combined experimental and theoretical study. We employ time-dependent density-functional theory (TDDFT) to compute the NEXAFS spectra of the open- and closed-shell metalloporphyrins CoTPP and ZnTPP as well as the free-base 2HTPP in realistic nonplanar conformations. Using Becke's well-known half-and-half hybrid functional, the computed core excitation spectra are mostly in good agreement with the experimental data in the low-energy region below the appropriate ionization threshold. To make these calculations feasible, we apply a new, simple scheme based on TDDFT using a modified single-particle input spectrum. This scheme is very easy to implement in standard codes and allows one to compute core excitation spectra at a similar cost as ordinary UV/vis spectra even for larger molecules. We employ these calculations for a detailed assignment of the NEXAFS spectra including subtle shifts in certain peaks of the N 1s spectra, which depend on the central coordination of the TPP ligand. We furthermore assign the observed NEXAFS resonances to the individual molecular subunits of the investigated TPP molecules.

Schmidt, Norman; Fink, Rainer [Department Chemie und Pharmazie, Lehrstuhl fuer Physikalische Chemie II and ICMM, Universitaet Erlangen-Nuernberg, Egerlandstrasse 3, 91058 Erlangen (Germany); Hieringer, Wolfgang [Department Chemie und Pharmazie, Lehrstuhl fuer Theoretische Chemie, Universitaet Erlangen-Nuernberg, Egerlandstrasse 3, 91058 Erlangen (Germany)

2010-08-07T23:59:59.000Z

214

BERAC Meeting September 5 2008 Gaithersburg MD | U.S. DOE Office of Science  

Office of Science (SC) Website

September 5 2008 Gaithersburg MD September 5 2008 Gaithersburg MD Biological and Environmental Research Advisory Committee (BERAC) BERAC Home Meetings BERAC Minutes BERAC Minutes Archive Members Charges/Reports Charter .pdf file (40KB) BER Committees of Visitors BER Home Meetings BERAC Meeting September 5 2008 Gaithersburg MD Print Text Size: A A A RSS Feeds FeedbackShare Page BER September 5, 2008 Arlington, VA Agenda Presentations Peg Riley .ppt file (357KB), Life and Medical Sciences Division Committee of Visitors Report Patricia Dehmer .ppt file (2.6MB), Report from the Office of Science Todd Anderson .ppt file (1.2MB), Scientific Focus Area (SFA) Rollout & Discussion Robert Dickinson .ppt file (6.1MB), Report on Climate Research Grand Challenges Mike Kuperberg .ppt file (975KB), Climate & Environmental Sciences

215

Critical cavity in the stretched fluid studied using square-gradient density-functional model with triple-parabolic free energy  

E-Print Network (OSTI)

The generic square-gradient density-functional model with triple-parabolic free energy is used to study the stability of a cavity introduced into the stretched liquid. The various properties of the critical cavity, which is the largest stable cavity within the liquid, are compared with those of the critical bubble of the homogeneous bubble nucleation. It is found that the size of the critical cavity is always smaller than that of the critical bubble, while the work of formation of the former is always higher than the latter in accordance with the conjectures made by Punnathanam and Corti [J. Chem. Phys. {\\bf 119}, 10224 (2003)] deduced from the Lennard-Jones fluids. Therefore their conjectures about the critical cavity size and the work of formation would be more general and valid even for other types of liquid such as metallic liquid or amorphous. However, the scaling relations they found for the critical cavity in the Lennard-Jones fluid are marginally satisfied only near the spinodal.

Masao Iwamatsu

2009-04-04T23:59:59.000Z

216

Mar. Drugs 2013, 11, 3350-3371; doi:10.3390/md11093350 marine drugs  

E-Print Network (OSTI)

Mar. Drugs 2013, 11, 3350-3371; doi:10.3390/md11093350 marine drugs ISSN 1660-3397 www% cytotoxicity was observed at the highest concentration tested (5 µg mL-1 ). However, OPEN ACCESS #12;Mar. Drugs Pinna had first been implicated in food poisoning in China in 1990 [1]. Pinnatoxin A (Pn

Recanati, Catherine

217

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

E-Print Network (OSTI)

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

Truong, Thanh N.

218

MD Study of Phase Change of Water inside a Carbon Nanotube Tatsuto KIMURA and Shigeo MARUYAMA  

E-Print Network (OSTI)

into ice crystal at 220 K or 200 K. In the case of phase change at 220 K, octagonal ice nanotube MD Study of Phase Change of Water inside a Carbon Nanotube * Tatsuto KIMURA and Shigeo MARUYAMA Dept. of Mech. Eng., The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 Phase change

Maruyama, Shigeo

219

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

E-Print Network (OSTI)

of studies have shown that a limited, regional nuclear war between India and Pakistan would cause significantIra 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

Robock, Alan

220

A computer simulated phantom study of tomotherapy dose optimization based on probability density functions (PDF) and potential errors caused by low reproducibility of PDF  

SciTech Connect

Lung tumor motion trajectories measured by four-dimensional CT or dynamic MRI can be converted to a probability density function (PDF), which describes the probability of the tumor at a certain position, for PDF based treatment planning. Using this method in simulated sequential tomotherapy, we study the dose reduction of normal tissues and more important, the effect of PDF reproducibility on the accuracy of dosimetry. For these purposes, realistic PDFs were obtained from two dynamic MRI scans of a healthy volunteer within a 2 week interval. The first PDF was accumulated from a 300 s scan and the second PDF was calculated from variable scan times from 5 s (one breathing cycle) to 300 s. Optimized beam fluences based on the second PDF were delivered to the hypothetical gross target volume (GTV) of a lung phantom that moved following the first PDF. The reproducibility between two PDFs varied from low (78%) to high (94.8%) when the second scan time increased from 5 s to 300 s. When a highly reproducible PDF was used in optimization, the dose coverage of GTV was maintained; phantom lung receiving 10%-20% prescription dose was reduced by 40%-50% and the mean phantom lung dose was reduced by 9.6%. However, optimization based on PDF with low reproducibility resulted in a 50% underdosed GTV. The dosimetric error increased nearly exponentially as the PDF error increased. Therefore, although the dose of the tumor surrounding tissue can be theoretically reduced by PDF based treatment planning, the reliability and applicability of this method highly depend on if a reproducible PDF exists and is measurable. By correlating the dosimetric error and PDF error together, a useful guideline for PDF data acquisition and patient qualification for PDF based planning can be derived.

Sheng, Ke; Cai Jing; Brookeman, James; Molloy, Janelle; Christopher, John; Read, Paul [Department of Radiation Oncology, University of Virginia, Charlottesville, Virginia 22908 (United States); Department of Radiology, University of Virginia, Charlottesville, Virginia 22908 (United States); Department of Radiation Oncology, University of Virginia, Charlottesville, Virginia 22908 and Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota 55905 (United States); Department of Radiology, University of Virginia, Charlottesville, Virginia 22908 (United States); Department of Radiation Oncology, University of Virginia, Charlottesville, Virginia 22908 (United States)

2006-09-15T23:59:59.000Z

Note: This page contains sample records for the topic "md density functional" from the National Library of EnergyBeta (NLEBeta).
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We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

CO Oxidation on supported single Pt atoms - Experimental and Ab Initio density functional studies of CO interaction with Pt atom on theta-alumina(010) surface  

Science Conference Proceedings (OSTI)

Although there are only a few known examples of supported single atoms, they are unique because they bridge the gap between homogenous and heterogeneous catalysis. The metal center is single supported atoms can be isoelectronic with their homogenous catalyst counterpart and may allow mechanistic pathways normally seen in homogenous catalysts. Here, we report CO oxidation activity of mono-disperse single Pt atoms supported on an inert substrate, -alumina (Al2O3), in the presence of stoichiometric oxygen. Since CO oxidation on single Pt atoms cannot occur via a conventional Langmuir-Hinshelwood scheme (L-H scheme) which requires at least one Pt-Pt bond, we have carried out a first principles density functional theoretical study of a proposed pathway which is a variation on the conventional L-H scheme and is inspired by organometallic chemistry of platinum. We find that a single supported Pt atom prefers to bond to O2 over CO. The CO then bonds with the oxygenated Pt atom and forms a carbonate which dissociates to liberate CO2, leaving an oxygen atom on Pt. A subsequent reaction with another CO molecule regenerates the single atom catalyst. An in-situ diffuse reflectance infrared study of CO adsorption on the catalyst s supported single atoms has been carried out to infer information on CO absorption modes and compare the observed spectra with calculated ones for intermediates in the proposed CO oxidation pathway. Our results clearly show that supported Pt single atoms are catalytically active and that this catalytic activity can occur without involving the substrate. Characterization by electron microscopy and X-ray absorption studies of the mono-disperse Pt/ -Al2O3, synthesized by solution methods, are also presented.

Narula, Chaitanya Kumar [ORNL; Debusk, Melanie Moses [ORNL; Yoon, Mina [ORNL; Allard Jr, Lawrence Frederick [ORNL; Mullins, David R [ORNL; Wu, Zili [ORNL; Yang, Xiaofan [ORNL; Veith, Gabriel M [ORNL; Stocks, George Malcolm [ORNL

2013-01-01T23:59:59.000Z

222

Single-Nucleon Densities  

NLE Websites -- All DOE Office Websites (Extended Search)

Densities Densities This web page presents single-nucleon densities calculated for a variety of nuclei in the range A=2-10 with some preliminary results for A=11,12. These are from variational Monte Carlo calculations (VMC) using the Argonne v18 two-nucleon and Urbana X three-nucleon potentials (AV18+UX). (Urbana X is intermediate between the Urbana IX and Illinois-7 models; it has the form of UIX supplemented with a two-pion S-wave piece, while the strengths of its terms are taken from the IL7 model. It does NOT have the three-pion-ring term of IL7.) These VMC wave functions are the starting trial functions for a number of recent Green's function Monte Carlo (GFMC) calculations: Brida, et al., Phys. Rev. C 84, 024319 (2011); McCutchan, et al., Phys. Rev. C 86, 024315 (2012);

223

Ceramic Composites, Inc. 1110 Benfield Blvd, Ste Q, Millersville, MD 21108  

NLE Websites -- All DOE Office Websites (Extended Search)

Composites, Inc. Composites, Inc. 1110 Benfield Blvd, Ste Q, Millersville, MD 21108 A subsidiary of Technology Assessment and Transfer, Inc. 410-987-3435 fax 410-987-7172 www.techassess.com AGENCY: DOE / NETL CONTRACT: DE-FG02-03ER83627 TITLE: Enhanced Performance Carbon Foam Heat Exchanger for Power Plant Cooling REPORT: Final Technical Report PERIOD: 21 July 2003 - 13 July 2007 TPOC: Barbara Carney carney@netl.doe.gov PHONE: 304-285-4671 PI: Steven Seghi steve@techassess.com PHONE: 410-987-3435 COMPANY: Ceramic Composites, Inc. 133 Defense Hwy, Ste 212 Annapolis, MD 21401 SBIR/STTR Rights Notice These SBIR/STTR data are furnished with SBIR/STTR rights under Grant No. DE-FG02- 03ER83627. For a period of 4 years after the acceptance of all items to be delivered under this

224

NAMD - The Engine for Large-Scale Classical MD Simulations of Biomolecular  

NLE Websites -- All DOE Office Websites (Extended Search)

NAMD NAMD NAMD - The Engine for Large-Scale Classical MD Simulations of Biomolecular Systems Based on a Polarizable Force Field PI Name: Benoit Roux PI Email: roux@uchicago.edu Institution: Argonne National Laboratory & University of Chicago Allocation Program: ESP Allocation Hours at ALCF: 80 Million Year: 2010 to 2013 Research Domain: Biological Sciences Biology, at the atomic and molecular level, is governed by complex interactions involving a large number of key constituents, including water, ions, proteins, nucleic acids, and lipid membranes. The goal of this project is to develop new technologies to simulate virtual models of biomolecular systems with an unprecedented accuracy. Large-scale molecular dynamics (MD) simulations based on atomic models play an increasingly

225

FINDING OF MD SIGNIFICANT IMPACT FORMERLY UTILIZED HED/AEC SITES REMEDIAL ACTION PROGRAM:  

Office of Legacy Management (LM)

FINDING OF MD SIGNIFICANT IMPACT FINDING OF MD SIGNIFICANT IMPACT FORMERLY UTILIZED HED/AEC SITES REMEDIAL ACTION PROGRAM: BAY0 CANYONS, NEW MEXICO Under the Formerly Utilized Sites Remedial Action Program (FUSRAP), the U.S. Department of Energy (DOE) has proposed to carry out rcmedfrl action at a site located in Bayo Canyon, Los Alamos County, New Mexico. Although the site as partially decontaminated and decommissioned in the 196Os, there remain above-background amounts of radionuclides. DOE has determined that strontium-90 in excess of DDE's proposed remedial- action criterir exists in subsurface materials underlying an area of about 0.6 ha (1.5 acres) at the Bayo Canyon site. The proposed action is to demarcate this are8 and restrict its use to activities that will not disturb this sub-

226

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

SciTech Connect

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.

Duan, Yuhua; Parlinski, K.

2011-01-01T23:59:59.000Z

227

Medication Safety in Older Adults: Home-Based Practice Patterns Joshua P. Metlay, MD, PhD,wzz  

E-Print Network (OSTI)

Medication Safety in Older Adults: Home-Based Practice Patterns Joshua P. Metlay, MD, Ph-reported sources of in- formation on current medications as well as home-based practices for organizing medication

Hennessy, Sean

228

Definition: Density Log | Open Energy Information  

Open Energy Info (EERE)

Density Log Density Log Jump to: navigation, search Dictionary.png Density Log Density logging is a well logging tool that can provide a continuous record of a formation's bulk density along the length of a borehole. In geology, bulk density is a function of the density of the minerals forming a rock (i.e. matrix) and the fluid enclosed in the pore spaces.[1] View on Wikipedia Wikipedia Definition Density logging is a well logging tool that can provide a continuous record of a formation's bulk density along the length of a borehole. In geology, bulk density is a function of the density of the minerals forming a rock and the fluid enclosed in the pore spaces. This is one of three well logging tools that are commonly used to calculate porosity, the other two being sonic logging and neutron porosity logging

229

Density estimation for data with rounding errors  

Science Conference Proceedings (OSTI)

Rounding of data is common in practice. The problem of estimating the underlying density function based on data with rounding errors is addressed. A parametric maximum likelihood estimator and a nonparametric bootstrap kernel density estimator are proposed. ... Keywords: Bootstrapping, Deconvolution density estimation, Fast Fourier transformation, Kernel density estimation, Measurement error

B. Wang, W. Wertelecki

2013-09-01T23:59:59.000Z

230

ANL/ALCF/ESP-13/14 NAMD - The Engine for Large-Scale Classical MD  

NLE Websites -- All DOE Office Websites (Extended Search)

4 4 NAMD - The Engine for Large-Scale Classical MD Simulations of Biomolecular Systems Based on a Polarizable Force Field ALCF-2 Early Science Program Technical Report Argonne Leadership Computing Facility About Argonne National Laboratory Argonne is a U.S. Department of Energy laboratory managed by UChicago Argonne, LLC under contract DE-AC02-06CH11357. The Laboratory's main facility is outside Chicago, at 9700 South Cass Avenue, Argonne, Illinois 60439. For information about Argonne and its pioneering science and technology programs, see www.anl.gov. Availability of This Report This report is available, at no cost, at http://www.osti.gov/bridge. It is also available on paper to the U.S. Department of Energy and its contractors, for a processing fee, from:

231

DOE Challenge Home Case Study, Nexus EnergyHomes, Frederick, MD, Production  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Nexus Nexus EnergyHomes Frederick, MD BUILDING TECHNOLOGIES OFFICE DOE Challenge Home builders are in the top 1% of builders in the country meeting the extraordinary levels of excellence and quality specifi ed by the U.S. Department of Energy. Every DOE Challenge Home starts with ENERGY STAR for Homes Version 3 for an energy-effi cient home built on a solid foundation of building science research. Then, even more advanced technologies are designed in for a home that goes above and beyond current code to give you the superior quality construction, HVAC, appliances, indoor air quality, safety, durability, comfort, and solar-ready components along with ultra-low or no utility bills. This provides homeowners with a quality home that will last for generations to come.

232

DEPARTMENT OF HEALTH AN~~.N~dtAN, MD. Y.P.H.  

Office of Legacy Management (LM)

,' ,...- ,' ,...- -., -.- . . we#lnty..: - DEPARTMENT OF HEALTH AN~~.N~dtAN, MD. Y.P.H. April 30, 1979 . _-- _' . U.S.E.P.A. Radiation Branch 26 Federal Plaz;a, Boom 9079 New York, N. Y. 10007 Attention: Miss Feldman:, Gentlemen: In accordance with your request to Calvin E. Weber, P.E., Assistant Commissioner of Health for Environmental Quality, I am forwarding a copy of a report prepared by him concerning a radiation survey conducted in the vicinity of the former Canadian Radium and Uranium Corpora+on plant on Railroad Avenue in the Village of Mount Kisco, Westchester County, New Yor Please transmit any comments you may have regarding this matter directly to Mr. Weber. Very truly Yours, Conmissioner of Health xc:rr cc: Sherwood Davies, P.E. lbm Cashman

233

Recipient: County of Howard, MD ENERGY EFFICIENCY AND CONSERVATION BLOCK GRANTS NEPA COMPLIANCE FORM  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

2 2 Recipient: County of Howard, MD ENERGY EFFICIENCY AND CONSERVATION BLOCK GRANTS NEPA COMPLIANCE FORM Activities Determination/ Categorical Exclusion Reviewer's Specific Instructions and Rationale (Restrictions and Allowable Activity) Electric Pick-up truck for on- site use at Alpha Ridge Landfill B5.1 None Landfill Forced Draft Heater A9 This CX applies to preliminary engineering and design tasks only. Additional information is required to make a NEPA determination for construction and operation tasks. Diesel Hybrid Truck B5.1 None Home Energy Audits A9 None Park Ballfield Lights Energy Efficiency B5.1 Waste Stream Clause Energy Efficiency Analysis via Monitoring of Sub-Meters Installation B5.1 None Energy Management Consultant A9 None High Efficiency Lighting - Rec & Parks B5.1

234

Recipient. County of Baltimore, MD ENERGY EFFICIENCY AND CONSERVATION BLOCK GRANTS NEPA  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

0 0 Recipient. County of Baltimore, MD ENERGY EFFICIENCY AND CONSERVATION BLOCK GRANTS NEPA COMPLIANCE FORM Activities Determination/ Categorical Exclusion Reviewer's Specific Instructions and Rationale (Restrictions and Allowable Activity) Renovation for the Green Resource Center B5.1 All administrative activities, audits, outreach, and technical advice should be CX'd. All EE activities are subject to the Waste Stream Clause, Historic Preservation clause, and Engineering clause. Energy Audits for Business & Government Structures A9, All, B5.1 None Revolving Loan Fund A9, All, B5.1 All administrative activities, audits, outreach, and technical advice should be CX'd. All EE activities are subject to the Waste Stream Clause, Historic Preservation clause, and Engineering clause.

235

Oral Histories: Dr. John W. Gofman, M.D., Ph.D.  

NLE Websites -- All DOE Office Websites (Extended Search)

7 7 HUMAN RADIATION STUDIES: REMEMBERING THE EARLY YEARS Oral History of Dr. John W. Gofman, M.D., Ph.D. Conducted December 20, 1994 United States Department of Energy Office of Human Radiation Experiments June 1995 CONTENTS Foreword Short Biography Oberlin College, Enrollment in Western Reserve Medical School To University of California, Berkeley to Study Physical Chemistry Assisting Seaborg's Research, Discovery of Uranium-233 The Manhattan Project From Research to Laboratory Production of Plutonium Joe Hamilton's Cavalier Approach to Radiation Medical Treatments With Radioactive Phosphorus (32P) Conflict Between University of California San Francisco and Berkeley Reflections on Ernest Lawrence Heart Disease Studies AEC Support for Heart Disease Studies Heparin and Lipoprotein Research With Human Subjects

236

Oral Histories: Oral History of Radiologist Henry I. Kohn, M.D., Ph.D.  

NLE Websites -- All DOE Office Websites (Extended Search)

1 1 HUMAN RADIATION STUDIES: REMEMBERING THE EARLY YEARS Oral History of Radiologist Henry I. Kohn, M.D., Ph.D. Conducted September 13, 1994 United States Department of Energy Office of Human Radiation Experiments June 1995 CONTENTS Foreword Short Biography Studying the Effects of X Rays on Animal Blood Chemistry at Oak Ridge Work at UCSF's Radiological Laboratory Advantages of Yeast Cells for Studying Radiation Effects Reflections on Bert Low-Beer and Joseph Hamilton Radiation Genetics Experiments on Mice Reflections on Reynold Brown and Henry Kaplan Establishment of Harvard's Joint Center for Radiation Therapy (Mid '60s) Radiological Assessment for the National Academy of Science Survey of Nuclear and Alternative Energy (1975–79) Biologist and Physicist Perspectives on Radiological Effects

237

Felix F? Camacho Governor Michael W. Cruz, M.D. Lieutenant Governor  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

O. Box 2950 Haghiia, Guam 96932 O. Box 2950 Haghiia, Guam 96932 TEL: (671) 472-8931 FAX: (671) 477-4826 EMAIL: governo@mail.gov.gu Felix F? Camacho Governor Michael W. Cruz, M.D. Lieutenant Governor 0 6 MAW 2009 The Honorable Steven Chu Secretary U.S. Department of Energy 1000 Independence Avenue, S. W. Washington, D.C. 20585 Re: State Energy Program Assurances Dear Secretary Chu: As a condition of receiving Guam's share of the $3.1 billion funding for the State Energy Program (SEP) under the American Recovery and Renewal Act of 2009 (H.R. l)(ARRA), I am providing the following assurances. I have written to the Consolidated Commission on Utilities, Guam's public utility commission, and requested that they consider additional actions to promote energy efficiency, consistent with the Federal

238

One-Particle Spectral Function and Local Density of States in a Phenomenological Mixed-Phase Model for High-Temperature Superconductors  

SciTech Connect

The dynamical properties of a recently introduced phenomenological model for high-temperature superconductors are investigated. In the clean limit, it was observed that none of the homogeneous or striped states that are induced by the model at low temperatures can reproduce the recent angle-resolved photoemission results for La{sub 2-x}Sr{sub x}CuO{sub 4} [Yoshida et al., Phys. Rev. Lett. 91, 027001 (2003)], which show a signal with two branches in the underdoped regime. On the other hand, upon including quenched disorder in the model and breaking the homogeneous state into 'patches' that are locally either superconducting or antiferromagnetic, the two-branch spectra can be reproduced. In this picture, the nodal regions are caused by d-wave superconducting clusters. Studying the density of states (DOS), a pseudogap is observed, caused by the mixture of the gapped antiferromagnetic state and a d-wave superconductor. The local DOS can be interpreted using a mixed-phase picture, similar to what is observed in tunneling experiments. It is concluded that a simple phenomenological model for cuprates can capture several of the one-particle features observed in the underdoped regime of these materials.

Mayr, Matthias [Max-Planck-Institut fur Feskorperforschung, Stuttgart, Germany; Alvarez, Gonzalo [ORNL; Moreo, Adriana [ORNL; Dagotto, Elbio R [ORNL

2006-01-01T23:59:59.000Z

239

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

E-Print Network (OSTI)

California Health eQuality Advisory Committee Kenneth W. Kizer, M.D., M.P.H. - Chair Distinguished Association (IHA) Ellen Wu, M.P.H. Executive Director California Pan-Ethnic Health Network Pamela L. Lane, M.S., RHIA, CPHIMS, Ex officio Deputy Secretary, HIE California Health & Human Services Agency Linette T

California at Davis, University of

240

Bivariate density estimation using BV regularisation  

Science Conference Proceedings (OSTI)

The problem of bivariate density estimation is studied with the aim of finding the density function with the smallest number of local extreme values which is adequate with the given data. Adequacy is defined via Kuiper metrics. The concept of the taut-string ... Keywords: Density estimation, Modality, Regularisation

Andreas Obereder; Otmar Scherzer; Arne Kovac

2007-08-01T23:59:59.000Z

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


241

Oral Histories: Physician James S. Robertson, M.D., Ph.D.  

NLE Websites -- All DOE Office Websites (Extended Search)

8 8 HUMAN RADIATION STUDIES: REMEMBERING THE EARLY YEARS Oral History of Physician James S. Robertson, M.D., Ph.D. Conducted January 20, 1995 United States Department of Energy Office of Human Radiation Experiments September 1995 CONTENTS Foreword Short Biography Education Research on Human Subjects at Berkeley Invited to Join the New Lab at Brookhaven (1950) Boron Neutron Capture Therapy Other AEC Biomedical Programs Brookhaven Human Use Committee Castle Bravo Atomic Weapon Test (March 1, 1954) Studies on Marshallese at Brookhaven Modern BNCT Treatment Leaves Brookhaven for the Mayo Clinic (1975) Joins the Department of Energy (1983) Work at the Naval Radiological Defense Laboratory (1953–55) Controversial Treatments and the "Crackpot File" FOREWORD I n December 1993, U.S. Secretary of Energy Hazel R. O'Leary announced her Openness Initiative. As part of this initiative, the Department of Energy undertook an effort to identify and catalog historical documents on radiation experiments that had used human subjects. The Office of Human Radiation Experiments coordinated the Department's search for records about these experiments. An enormous volume of historical records has been located. Many of these records were disorganized; often poorly cataloged, if at all; and scattered across the country in holding areas, archives, and records centers.

242

Validation of Density Functional Theory for Materials  

Science Conference Proceedings (OSTI)

... One of the the crucial aspects in high-throughput computational screening of metal-organic frameworks (MOFs) for carbon capture and other ...

2013-07-18T23:59:59.000Z

243

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

Science Conference Proceedings (OSTI)

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.

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

1980-10-01T23:59:59.000Z

244

Scattering Length Density Calculator  

Science Conference Proceedings (OSTI)

... For energy dependent cross sections please go to ... The neutron scattering length density is defined ... To calculate scattering length densities enter a ...

245

The Use of the Weibull Three-Parameter Model for Estimating Mean Wind Power Densities  

Science Conference Proceedings (OSTI)

The Weibull three-parameter model is discussed for estimation of mean wind power densities. This probability density function is a generalization of a number of more conventional density functions. Using wind speed observations, it is shown that ...

L. Van Der Auwera; F. De Meyer; L. M. Malet

1980-07-01T23:59:59.000Z

246

A first-principles density functional theory study of the electronic structural and thermodynamic properties of M2ZrO3 and M2CO3 (M=Na, K) and their capabilities for CO2 capture  

SciTech Connect

Alkali metal zirconates could be used as solid sorbents for CO{sub 2} capture. The structural, electronic, and phonon properties of Na{sub 2}ZrO{sub 3}, K{sub 2}ZrO{sub 3}, Na{sub 2}CO{sub 3}, and K{sub 2}CO{sub 3} are investigated by combining the density functional theory with lattice phonon dynamics. The thermodynamics of CO{sub 2} absorption/desorption reactions of these two zirconates are analyzed. The calculated results show that their optimized structures are in a good agreement with experimental measurements. The calculated band gaps are 4.339 eV (indirect), 3.641 eV (direct), 3.935 eV (indirect), and 3.697 eV (direct) for Na{sub 2}ZrO{sub 3}, K{sub 2}ZrO{sub 3}, Na{sub 2}CO{sub 3}, and K{sub 2}CO{sub 3}, respectively.The calculated phonon dispersions and phonon density of states for M{sub 2}ZrO{sub 3} and M{sub 2}CO{sub 3} (M = K, Na, Li) revealed that from K to Na to Li, their frequency peaks are shifted to high frequencies due to the molecular weight decreased from K to Li. From the calculated reaction heats and relationships of free energy change versus temperatures and CO{sub 2} pressures of the M{sub 2}ZrO{sub 3} (M = K, Na, Li) reacting with CO{sub 2}, we found that the performance of Na{sub 2}ZrO{sub 3} capturing CO{sub 2} is similar to that of Li{sub 2}ZrO{sub 3} and is better than that of K{sub 2}ZrO{sub 3}. Therefore, Na{sub 2}ZrO{sub 3} and Li{sub 2}ZrO{sub 3} are good candidates of high temperature CO{sub 2} sorbents and could be used for post combustion CO{sub 2} capture technologies.

Yuhua Duan

2012-01-01T23:59:59.000Z

247

Considering Air Density in Wind Power Production  

E-Print Network (OSTI)

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.

Zénó Farkas

2011-03-11T23:59:59.000Z

248

Estimate of dielectric density using spectroscopic ellipsometry  

Science Conference Proceedings (OSTI)

The optical dielectric functions for hafnium oxide and hafnium silicate films were extracted from spectroscopic ellipsometry measurements and the density then calculated using a previously proposed method. The values obtained were then compared to those ... Keywords: Density, Gadolinium oxide, Hafnium silicate, Medium energy ion scattering, Spectroscopic ellipsometry, X-ray reflectometry

W. Davey; O. Buiu; M. Werner; I. Z. Mitrovic; S. Hall; P. Chalker

2009-07-01T23:59:59.000Z

249

Orthobaric Density: A Thermodynamic Variable for Ocean Circulation Studies  

Science Conference Proceedings (OSTI)

A new density variable, empirically corrected for pressure, is constructed. This is done by first fitting compressibility (or sound speed) computed from global ocean datasets to an empirical function of pressure and in situ density (or specific ...

Roland A. de Szoeke; Scott R. Springer; David M. Oxilia

2000-11-01T23:59:59.000Z

250

Determining Relative f and d Orbital Contributions to M?Cl Covalency in MCl62– (M = Ti, Zr, Hf, U) and UOCl5 Using Cl K-Edge X-ray Absorption Spectroscopy and Time-Dependent Density Functional Theory  

SciTech Connect

Chlorine K-edge X-ray absorption spectroscopy (XAS) and ground-state and time-dependent hybrid density functional theory (DFT) were used to probe electronic structure for O{sub h}-MCl{sub 6}{sup 2-}(M = Ti, Zr, Hf, U) and C{sub 4v}-UOCl{sub 5}{sup -}, and to determine the relative contributions of valence 3d, 4d, 5d, 6d, and 5f orbitals in M-Cl bonding. Spectral interpretations were guided by time-dependent DFT calculated transition energies and oscillator strengths, which agree well with the experimental XAS spectra. The data provide new spectroscopic evidence for the involvement of both 5f and 6d orbitals in actinide-ligand bonding in UCl{sub 6}{sup 2-}. For the MCl{sub 6}{sup 2-}, where transitions into d orbitals of t{sub 2g} symmetry are spectroscopically resolved for all four complexes, the experimentally determined Cl 3p character per M-Cl bond increases from 8.3(4)% (TiCl{sub 6}{sup 2-}) to 10.3(5)% (ZrCl{sub 6}{sup 2-}), 12(1)% (HfCl{sub 6}{sup 2-}), and 26 18(1)% (UCl{sub 6}{sup 2-}). Chlorine K-edge XAS spectra of UOCl{sub 5}{sup -} provide additional insights into the transition assignments by 27 lowering the symmetry to C{sub 4v}, where five pre-edge transitions into both 5f and 6d orbitals are observed. For UCl{sub 6}{sup 2-}, the XAS data 28 suggest that orbital mixing associated with the U 5f orbitals is considerably lower than that of the U 6d orbitals. For both UCl{sub 6}{sup 2-}29 and UOCl{sub 5}{sup -}, the ground-state DFT calculations predict a larger 5f contribution to bonding than is determined experimentally. 30 These findings are discussed in the context of conventional theories of covalent bonding for d- and f-block metal complexes.

Minasian, Stefan G.; Keith, Jason M.; Batista, Enrique R.; Boland, Kevin S.; Clark, David L.; Conradson, Steven D.; Kozimor, Stosh A.; Martin, Richard L.; Schwarz, Daniel E.; Shuh, David K.; Wagner, Gregory L.; Wilkerson, Marianne P.; Wolfsberg, Laura E.; Yang, Ping

2012-03-09T23:59:59.000Z

251

Low density, resorcinol-formaldehyde aerogels  

DOE Patents (OSTI)

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.

Pekala, R.W.

1989-10-10T23:59:59.000Z

252

Low density, resorcinol-formaldehyde aerogels  

DOE Patents (OSTI)

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 {le}100 mg/cc; cell size {le}0.1 microns). The aerogels are transparent, dark red in color and consist of interconnected colloidal-like particles with diameters of about 100 A{degrees}. These aerogels may be further carbonized to form low density carbon foams with cell size of about 0.1 micron. 1 ref., 1 tab.

Pekala, R.W.

1989-09-12T23:59:59.000Z

253

Low density, resorcinol-formaldehyde aerogels  

DOE Patents (OSTI)

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.

Pekala, Richard W. (Pleasant Hill, CA)

1989-01-01T23:59:59.000Z

254

Low density, resorcinol-formaldehyde aerogels  

DOE Patents (OSTI)

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.

Pekala, Richard W. (Pleasant Hill, CA)

1991-01-01T23:59:59.000Z

255

Probability Densities in Strong Turbulence  

E-Print Network (OSTI)

According to modern developments in turbulence theory, the "dissipation" scales (u.v. cut-offs) $\\eta$ form a random field related to velocity increments $\\delta_{\\eta}u$. In this work we, using Mellin's transform combined with the Gaussain large -scale boundary condition, calculate probability densities (PDFs) of velocity increments $P(\\delta_{r}u,r)$ and the PDF of the dissipation scales $Q(\\eta, Re)$, where $Re$ is the large-scale Reynolds number. The resulting expressions strongly deviate from the Log-normal PDF $P_{L}(\\delta_{r}u,r)$ often quoted in the literature. It is shown that the probability density of the small-scale velocity fluctuations includes information about the large (integral) scale dynamics which is responsible for deviation of $P(\\delta_{r}u,r)$ from $P_{L}(\\delta_{r}u,r)$. A framework for evaluation of the PDFs of various turbulence characteristics involving spatial derivatives is developed. The exact relation, free of spurious Logarithms recently discussed in Frisch et al (J. Fluid Mech. {\\bf 542}, 97 (2005)), for the multifractal probability density of velocity increments, not based on the steepest descent evaluation of the integrals is obtained and the calculated function $D(h)$ is close to experimental data. A novel derivation (Polyakov, 2005), of a well-known result of the multi-fractal theory [Frisch, "Turbulence. {\\it Legacy of A.N.Kolmogorov}", Cambridge University Press, 1995)), based on the concepts described in this paper, is also presented.

Victor Yakhot

2005-12-12T23:59:59.000Z

256

Density | OpenEI  

Open Energy Info (EERE)

Density Density Dataset Summary Description This dataset is part of a larger internal dataset at the National Renewable Energy Laboratory (NREL) that explores various characteristics of large solar electric (both PV and CSP) facilities around the United States. This dataset focuses on the land use characteristics for solar facilities that are either under construction or currently in operation. Source Land-Use Requirements for Solar Power Plants in the United States Date Released June 25th, 2013 (5 months ago) Date Updated Unknown Keywords acres area average concentrating solar power csp Density electric hectares km2 land land requirements land use land-use mean photovoltaic photovoltaics PV solar statistics Data application/vnd.openxmlformats-officedocument.spreadsheetml.sheet icon Master Solar Land Use Spreadsheet (xlsx, 1.5 MiB)

257

Multiple density layered insulator  

DOE Patents (OSTI)

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.

Alger, T.W.

1994-09-06T23:59:59.000Z

258

Multiple density layered insulator  

DOE Patents (OSTI)

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.

Alger, Terry W. (Tracy, CA)

1994-01-01T23:59:59.000Z

259

Local Atomic Density of Microporous Carbons  

DOE Green Energy (OSTI)

We investigated the structure of two disordered carbons: activated carbon fibers (ACF) and ultramicroporous carbon (UMC). These carbons have highly porous structure with large surface areas and consequently low macroscopic density that should enhance adsorption of hydrogen. We used the atomic pair distribution function to probe the local atomic arrangements. The results show that the carbons maintain an in-plane local atomic structure similar to regular graphite, but the stacking of graphitic layers is strongly disordered. Although the local atomic density of these carbons is lower than graphite, it is only {approx}20% lower and is much higher than the macroscopic density due to the porosity of the structure. For this reason, the density of graphene sheets that have optimum separation for hydrogen adsorption is lower than anticipated.

Dmowski, Wojtek; Contescu, Cristian I.; Llobet, Anna; Gallego, Nidia C.; Egami, Takeskhi (Tennessee-K); (ORNL); (LANL)

2012-07-12T23:59:59.000Z

260

Nonlinear spectral density estimation: thresholding the correlogram  

E-Print Network (OSTI)

in a nonlinear way. The rate of convergence of the new estimators is quantified, and practical issues estimation of the spectral density function; examples include astronomy, economics, electrical engineering Einstein (1914); see Brillinger (1993) for a historical perspective. The prevalent spectral estimation

Politis, Dimitris N.

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


261

Near quantitative agreement of model free DFT- MD predictions with XAFS observations of the hydration structure of highly charged transition metal ions  

Science Conference Proceedings (OSTI)

DFT-MD simulations (PBE96 and PBE0) with MD-XAFS scattering calculations (FEFF9) show near quantitative agreement with new and existing XAFS measurements for a comprehensive series of transition metal ions which interact with their hydration shells via complex mechanisms (high spin, covalency, charge transfer, etc.). This work was supported by the U.S. Department of Energy (DOE), Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences and Biosciences. Pacific Northwest National Laboratory (PNNL) is operated for the U.S. DOE by Battelle. A portion of the research was performed using EMSL, a national scientific user facility sponsored by the U.S. DOE's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory.

Fulton, John L.; Bylaska, Eric J.; Bogatko, Stuart A.; Balasubramanian, Mahalingam; Cauet, Emilie L.; Schenter, Gregory K.; Weare, John H.

2012-09-20T23:59:59.000Z

262

Phase Diagram of Amorphous Solid Water: Low-Density, High-Density, and Very-High-Density Amorphous Ices  

E-Print Network (OSTI)

We describe the phase diagram of amorphous solid water by performing molecular dynamics simulations. Our simulations follow different paths in the phase diagram: isothermal compression/decompression, isochoric cooling/heating and isobaric cooling/heating. We are able to identify low-density amorphous (LDA), high-density amorphous (HDA), and very-high density amorphous (VHDA) ices. The density $\\rho$ of these glasses at different pressure $P$ and temperature $T$ agree well with experimental values. We also study the radial distribution functions of glassy water. We obtain VHDA by isobaric heating of HDA, as in experiment. We also find that ``other forms'' of glassy water can be obtained upon isobaric heating of LDA, as well as amorphous ices formed during the transformation of LDA to HDA. We argue that these other forms of amorphous ices, as well as VHDA, are not altogether new glasses but rather are the result of aging induced by heating. Samples of HDA and VHDA with different densities are recovered at normal $P$, showing that there is a continuum of glasses. Furthermore, the two ranges of densities of recovered HDA and recovered VHDA overlap at ambient $P$. Our simulations are consistent with the possibility of HDA$\\to$LDA and VHDA$\\to$LDA transformations, reproducing the experimental findings. We do not observe a VHDA$\\to$HDA transformation.

Nicolas Giovambattista; H. Eugene Stanley; Francesco Sciortino

2005-02-22T23:59:59.000Z

263

High Energy Density Capacitors  

SciTech Connect

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.

None

2010-07-01T23:59:59.000Z

264

Anomalous evolution of Ar metastable density with electron density in high density Ar discharge  

SciTech Connect

Recently, an anomalous evolution of argon metastable density with plasma discharge power (electron density) was reported [A. M. Daltrini, S. A. Moshkalev, T. J. Morgan, R. B. Piejak, and W. G. Graham, Appl. Phys. Lett. 92, 061504 (2008)]. Although the importance of the metastable atom and its density has been reported in a lot of literature, however, a basic physics behind the anomalous evolution of metastable density has not been clearly understood yet. In this study, we investigated a simple global model to elucidate the underlying physics of the anomalous evolution of argon metastable density with the electron density. On the basis of the proposed simple model, we reproduced the anomalous evolution of the metastable density and disclosed the detailed physics for the anomalous result. Drastic changes of dominant mechanisms for the population and depopulation processes of Ar metastable atoms with electron density, which take place even in relatively low electron density regime, is the clue to understand the result.

Park, Min; Chang, Hong-Young [Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701 (Korea, Republic of); You, Shin-Jae; Kim, Jung-Hyung [Center for Vacuum Technology, Korea Research Institute of Standards and Science, Daejeon, 305-306 (Korea, Republic of); Shin, Yong-Hyeon

2011-10-15T23:59:59.000Z

265

Low density, resorcinol-formaldehyde aerogels  

DOE Patents (OSTI)

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.

Pekala, R.W.

1988-05-26T23:59:59.000Z

266

Energy density for chiral lattice fermions with chemical potential  

E-Print Network (OSTI)

We study a recently proposed formulation of overlap fermions at finite density. In particular we compute the energy density as a function of the chemical potential and the temperature. It is shown that overlap fermions with chemical potential reproduce the correct continuum behavior.

Gattringer, Christof

2007-01-01T23:59:59.000Z

267

Charge Density Wave Compounds  

NLE Websites -- All DOE Office Websites (Extended Search)

Fisher Research Group Fisher Research Group Layered Chalcogenides 29 February 2008 Controlling the Wave by Brad Plummer, SLAC Communications Stanford University researchers working in part at SSRL have discovered a novel set of properties pertaining to a compound of materials called tritellurides. These compounds, composed of three atoms of tellurium and a single atom of one of the rare earth elements, demonstrate unique electronic properties that can be controlled by altering the temperature of the material. The tritellurides display phenomena known as charge density waves (CDW). In a normal conductive metal, electrons persist in a "sea" wherein they are evenly distributed and equally available, or conductive. A CDW occurs under certain circumstances and causes the electrons to clump together, lowering their availability, and thereby lowering the compound's conductivity. Tellurium, when crystallized into quasi-two-dimensional planes and combined with rare earth elements, produces a material with CDWs that can be manipulated and controlled.

268

Low density microcellular foams  

DOE Patents (OSTI)

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.

LeMay, James D. (Castro Valley, CA)

1992-01-01T23:59:59.000Z

269

Low density microcellular foams  

DOE Patents (OSTI)

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.

LeMay, James D. (Castro Valley, CA)

1991-01-01T23:59:59.000Z

270

Density Coordinate Mixed Layer Models  

Science Conference Proceedings (OSTI)

The development of mixed layer models in so-called density coordinates is discussed. Density coordinates, or isopycnal coordinates as they are sometimes called, are becoming increasingly popular for use in ocean models due to their highly ...

William K. Dewar

2001-02-01T23:59:59.000Z

271

Reduced-Memory Decoding of Low-Density Lattice Codes  

E-Print Network (OSTI)

This letter describes a belief-propagation decoder for low-density lattice codes of finite dimension, in which the messages are represented as single Gaussian functions. Compared to previously-proposed decoders, memory is ...

Kurkoski, Brian

272

Large Scale Computing Requirements for Basic Energy Sciences (An BES / ASCR / NERSC Workshop) Hilton Washington DC/Rockville Meeting Center, Rockville MD 3D Geophysical Imaging  

NLE Websites -- All DOE Office Websites (Extended Search)

Requirements Requirements for Basic Energy Sciences (An BES / ASCR / NERSC Workshop) Hilton Washington DC/Rockville Meeting Center, Rockville MD 3D Geophysical Modeling and Imaging G. A. Newman Lawrence Berkeley National Laboratory February 9 - 10 , 2010 Talk Outline * SEAM Geophysical Modeling Project - Its Really Big! * Geophysical Imaging (Seismic & EM) - Its 10 to 100x Bigger! - Reverse Time Migration - Full Waveform Inversion - 3D Imaging & Large Scale Considerations - Offshore Brazil Imaging Example (EM Data Set) * Computational Bottlenecks * Computing Alternatives - GPU's & FPGA's - Issues Why ? So that the resource industry can tackle grand geophysical challenges (Subsalt imaging, land acquisition, 4-D, CO2, carbonates ......) SEAM Mission Advance the science and technology of applied

273

An Algorithm for Lidar Mapping of Aerosol Concentrations in a Varying Atmospheric Background Density  

Science Conference Proceedings (OSTI)

An algorithm for the determination of the number density profiles of a specific aerosol as a function of time and space is developed and discussed. The algorithm is applicable to atmospheric conditions in which a varying density particulate ...

Moshe Kleiman; Smadar Egert; Ariel Cohen

1986-12-01T23:59:59.000Z

274

A short remark on negative energy densities and quantum inequalities  

E-Print Network (OSTI)

In quantum field theory it is generally known that the energy density may be negative at a given point in spacetime. A number of papers have shown that there is a restriction on this energy density which is called a quantum inequality (QI). A QI is the lower bound to the "weighted average" of the energy density at a given point integrated over a time dependent sampling function. In this paper we give an example of a sampling function for which there is no QI.

Solomon, Dan

2009-01-01T23:59:59.000Z

275

A short remark on negative energy densities and quantum inequalities  

E-Print Network (OSTI)

In quantum field theory it is generally known that the energy density may be negative at a given point in spacetime. A number of papers have shown that there is a restriction on this energy density which is called a quantum inequality (QI). A QI is the lower bound to the "weighted average" of the energy density at a given point integrated over a time dependent sampling function. In this paper we give an example of a sampling function for which there is no QI.

Dan Solomon

2009-01-05T23:59:59.000Z

276

Density Inhomogeneities and Electron Mobility in Supercritical Xenon  

NLE Websites -- All DOE Office Websites (Extended Search)

Density Inhomogeneities and Electron Mobility in Supercritical Xenon Density Inhomogeneities and Electron Mobility in Supercritical Xenon Richard A. Holroyd, Kengo Itoh, and Masaru Nishikawa J. Chem. Phys. 118, 706-710 (2003) [Find paper at Scitation] Abstract: The low-field mobility of electrons in supercritical Xe has been measured isothermally as a function of density above the critical temperature (289.7 K). At 293 K the mobility varies from a high of 890 cm2/Vs at 9.2 x 1021 atoms/cm3 to a minimum value of 4.6 cm2/Vs at a density of 3.5 x 1021 atoms/cm3, which is just below the critical density. The density dependence of the mobility is reasonably well predicted by the deformation potential model if the adiabatic compressibility is used to characterize the electron-medium interactions. Approximate agreement indicates that

277

Density rise experiment on PLT  

SciTech Connect

The evolution of the density profile in PLT during intense gas puffing is documented and analyzed. Measurements of the spectrum of low energy edge neutrals and of the change in central neutral density indicate that charge-exchange processes alone cannot account for the central density rise. The transient density profile changes can be reproduced numerically by a diffusivity of approx. 10/sup 4/ cm/sup 2//s, and a spatially averaged inward flow of 10/sup 3/ cm/s. These transport coefficients are 10 ..-->.. 10/sup 2/ times larger than neoclassical. The ion energy confinement is reduced, the small scale density fluctuations are increased, and runaway electrons losses are increased during the density rise.

Strachan, J.D.; Bretz, N.; Mazzucato, E.

1982-05-01T23:59:59.000Z

278

Energy Densities for LLNL EMB  

Summary of Projected Power and Energy Density Parameters for the “New Generation” LLNL Electromechanical Batteries R.F. Post June 24, 2013

279

Yield Strength as a Function of Dislocation Density  

E-Print Network (OSTI)

.Vander Voort, George. Metallography Principles and Practices. New York: McGraw-Hill, 1984. 2.Shackelford

Collins, Gary S.

280

Surface Symmetry Energy of Nuclear Energy Density Functionals.  

E-Print Network (OSTI)

??The thesis studies the bulk deformation properties of the Skyrme nuclear energy densityfunctionals. Following simple arguments based on the leptodermous expansion andliquid drop model, the… (more)

Nikolov, Nikola Iliev

2011-01-01T23:59:59.000Z

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


281

108- Density Functional Theory Study of Oxygen Vacancy Migration ...  

Science Conference Proceedings (OSTI)

125- Influence of Gas Flow Rate Ratio on the Structural Properties of a-SiC:H Prepared by ... 145- The Synergy of XRD and XRF in a Shale and Slate Analysis.

282

Density Functional Theory Based Calculations of Site Occupancy in ...  

Science Conference Proceedings (OSTI)

A comparison is made between the site occupancy behavior based on two .... First Principles Modeling of Shape Memory Alloy Magnetic Refrigeration Materials ... Forming-Crush Simulation Optimization Using Internal State Variable Model.

283

United abominations: Density functional studies of heavy metal chemistry  

Science Conference Proceedings (OSTI)

Carbonyl and nitrile addition to uranyl (UO{sup 2}{sup 2+}) are studied. The competition between nitrile and water ligands in the formation of uranyl complexes is investigated. The possibility of hypercoordinated uranyl with acetone ligands is examined. Uranyl is studied with diactone alcohol ligands as a means to explain the apparent hypercoordinated uranyl. A discussion of the formation of mesityl oxide ligands is also included. A joint theory/experimental study of reactions of zwitterionic boratoiridium(I) complexes with oxazoline-based scorpionate ligands is reported. A computational study was done of the catalytic hydroamination/cyclization of aminoalkenes with zirconium-based catalysts. Techniques are surveyed for programming for graphical processing units (GPUs) using Fortran.

Schoendorff, George

2012-04-02T23:59:59.000Z

284

Recovering Risk-Neutral Probability Density Functions from Options ...  

E-Print Network (OSTI)

Theorem 2 provides us with a simple mechanism to eliminate "artificial" arbitrage ..... options prices: An application to crude oil during theI˛ ulfcw risis. © oŁ rd¨.

285

Density Functional Theory in Surface Chemistry and Catalysis  

SciTech Connect

Recent advances in the understanding of reactivity trends for chemistry at transition metal surfaces have enabled in silico design of heterogeneous catalysts in a few cases. Current status of the field is discussed with an emphasis on the role of coupling between theory and experiment and future challenges.

Norskov, Jens

2011-05-19T23:59:59.000Z

286

Density Functional Theory Simulations Predict New Materials for...  

NLE Websites -- All DOE Office Websites (Extended Search)

of these new physical phenomena suggests the design of a high- capacity magnesium-boron battery. NREL is a national laboratory of the U.S. Department of Energy, Office of Energy...

287

Magnetic and antimagnetic rotation in covariant density functional theory  

Science Conference Proceedings (OSTI)

Progress on microscopic and self-consistent description of the magnetic rotation and antimagnetic rotation phenomena in tilted axis cranking relativistic mean-field theory based on a point-coupling interaction are briefly reviewed. In particular, the microscopic pictures of the shears mechanism in {sup 60}Ni and the two shears-like mechanism in {sup 105}Cd are discussed.

Zhao, P. W.; Liang, H. Z.; Peng, J.; Ring, P.; Zhang, S. Q.; Meng, J. [State Key Lab Nucl. Phys. and Tech., School of Physics, Peking University, Beijing 100871 (China); Department of Physics, Beijing Normal University, Beijing 100875 (China); State Key Lab Nucl. Phys. and Tech., School of Physics, Peking University, Beijing 100871 (China) and Physik Department, Technische Universitat Muenchen, D-85747 Garching (Germany); State Key Lab Nucl. Phys. and Tech., School of Physics, Peking University, Beijing 100871 (China); State Key Lab Nucl. Phys. and Tech., School of Physics, Peking University, Beijing 100871 (China) and Department of Physics, University of Stellenbosch, Stellenbosch (South Africa)

2012-10-20T23:59:59.000Z

288

Nonlocal exchange correlation in screened-exchange density functional methods  

E-Print Network (OSTI)

sX-)LDA and the self-energy matrix elements of GW. We ?rstGW results, where the self-energy matrix elements of GW are

Lee, Byounghak; Wang, Lin-Wang; Spataru, Catalin D.; Louie, Steven G.

2007-01-01T23:59:59.000Z

289

RICE UNIVERSITY Linear Scaling Density Functional Theory with  

E-Print Network (OSTI)

Scho¨nle1 , Dirk Kamin2 , Volker Westphal1 , Silvio O. Rizzoli2 , and Stefan W. Hell *; 1 1 Department laser (Fiber Drive, Blue Sky, Re- search, Milpitas, CA, USA) at a wavelength of 635 nm and it was turned by a re- search grant from the German Ministry for Education and Research (BMBF): Nanolive. MAL

Scuseria, Gustavo E.

290

D12: Density Functional Study of Uranium-Niobium System  

Science Conference Proceedings (OSTI)

Calculation results show that the ? phase in U-Nb system tends to be stabilized ... A18: Effect of Local Alendronate Delivery on In Vivo Osteogenesis From PCL Coated .... C19: Dissolution Behavior of Cu Under Bump Metallization in Ball Grid Array ... Volume and Fast Turnaround Automated Inline TEM Sample Preparation

291

Density-based logistic regression  

Science Conference Proceedings (OSTI)

This paper introduces a nonlinear logistic regression model for classification. The main idea is to map the data to a feature space based on kernel density estimation. A discriminative model is then learned to optimize the feature weights as well as ... Keywords: density estimation, logistic regression, medical prediction, nonlinear classification

Wenlin Chen, Yixin Chen, Yi Mao, Baolong Guo

2013-08-01T23:59:59.000Z

292

Computing 1-D atomic densities in macromolecular simulations: the Density Profile Tool for VMD  

E-Print Network (OSTI)

Molecular dynamics simulations have a prominent role in biophysics and drug discovery due to the atomistic information they provide on the structure, energetics and dynamics of biomolecules. Specialized software packages are required to analyze simulated trajectories, either interactively or via scripts, to derive quantities of interest and provide insight for further experiments. This paper presents the Density Profile Tool, a package that enhances the Visual Molecular Dynamics environment with the ability to interactively compute and visualize 1-D projections of various density functions of molecular models. We describe how the plugin is used to perform computations both via a graphical interface and programmatically. Results are presented for realistic examples, all-atom bilayer models, showing how mass and electron densities readily provide measurements such as membrane thickness, location of structural elements, and how they compare to X-ray diffraction experiments.

Giorgino, Toni

2013-01-01T23:59:59.000Z

293

Density Log | Open Energy Information  

Open Energy Info (EERE)

Density Log Density Log Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Density Log Details Activities (6) Areas (6) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Downhole Techniques Exploration Sub Group: Well Log Techniques Parent Exploration Technique: Well Log Techniques Information Provided by Technique Lithology: provides data on the bulk density of the rock surrounding the well Stratigraphic/Structural: Stratigraphic correlation between well bores. Hydrological: Porosity of the formations loggesd can be calculated for the Density log andprovide an indication potential aquifers. Thermal: Cost Information Low-End Estimate (USD): 0.4040 centUSD 4.0e-4 kUSD 4.0e-7 MUSD 4.0e-10 TUSD / foot Median Estimate (USD): 0.6868 centUSD

294

Low density carbonized composite foams  

DOE Patents (OSTI)

A carbonized composite foam having a density less than about 50 mg/cm{sup 3} and individual cell sizes no greater than about 1 {mu}m in diameter is described, and the process of making it. 3 figs.

Kong, Fung-Ming.

1989-12-07T23:59:59.000Z

295

Quarkonium at nonzero isospin density  

E-Print Network (OSTI)

We calculate the energies of quarkonium bound states in the presence of a medium of nonzero isospin density using lattice QCD. The medium, created using a canonical (fixed isospin charge) approach, induces a reduction of ...

Detmold, William

296

Modelling charge transfer reactions with the frozen density embedding formalism  

SciTech Connect

The frozen density embedding (FDE) subsystem formulation of density-functional theory is a useful tool for studying charge transfer reactions. In this work charge-localized, diabatic states are generated directly with FDE and used to calculate electronic couplings of hole transfer reactions in two {pi}-stacked nucleobase dimers of B-DNA: 5{sup '}-GG-3{sup '} and 5{sup '}-GT-3{sup '}. The calculations rely on two assumptions: the two-state model, and a small differential overlap between donor and acceptor subsystem densities. The resulting electronic couplings agree well with benchmark values for those exchange-correlation functionals that contain a high percentage of exact exchange. Instead, when semilocal GGA functionals are used the electronic couplings are grossly overestimated.

Pavanello, Michele [Gorlaeus Laboratories, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden (Netherlands); Neugebauer, Johannes [Institute for Physical and Theoretical Chemistry, Technische Universitaet Braunschweig, Hans-Sommer-Strasse 10, 38106 Braunschweig (Germany)

2011-12-21T23:59:59.000Z

297

The string of variable density: Further results  

Science Conference Proceedings (OSTI)

We analyze the problem of calculating the solutions and the spectrum of a string with arbitrary density and fixed ends. We build a perturbative scheme which uses a basis of WKB-type functions and obtain explicit expressions for the eigenvalues and eigenfunctions of the string. Using this approach we show that it is possible to derive the asymptotic (high energy) behavior of the string, obtaining explicit expressions for the first three coefficients (the first two can also be obtained with the WKB method). Finally, using an iterative approach we also obtain analytical expressions for the low energy behavior of the eigenvalues and eigenfunctions of a string with rapidly oscillating density, recovering (in a simpler way) results in the literature. - Highlights: > We devise a perturbative approach to finding the modes of a string with arbitrary density. > We obtain explicitly the first three coefficients of the asymptotic high energy expansion. > We apply our findings to a series of examples, obtaining both analytical and numerical results.

Amore, Paolo, E-mail: paolo.amore@gmail.com

2011-09-15T23:59:59.000Z

298

OPTIMIZATION OF LAYER DENSITIES FOR MULTILAYERED INSULATION SYSTEMS  

Science Conference Proceedings (OSTI)

Numerous tests of various multilayer insulation systems have indicated that there are optimal densities for these systems. However, the only method of calculating this optimal density was by a complex physics based algorithm developed by McIntosh. In the 1970's much data were collected on the performance of these insulation systems with many different variables analyzed. All formulas generated included number of layers and layer density as geometric variables in solving for the heat flux, none of them was in a differentiable form for a single geometric variable. It was recently discovered that by converting the equations from heat flux to thermal conductivity using Fourier's Law, the equations became functions of layer density, temperatures, and material properties only. The thickness and number of layers of the blanket were merged into a layer density. These equations were then differentiated with respect to layer density. By setting the first derivative equal to zero, and solving for the layer density, the critical layer density was determined. This method was checked and validated using test data from the Multipurpose Hydrogen Testbed which was designed using Mcintosh's algorithm.

Johnson, W. L. [NASA Kennedy Space Center, KT-E Kennedy Space Center, FL 32899 (United States)

2010-04-09T23:59:59.000Z

299

Rock Density | Open Energy Information  

Open Energy Info (EERE)

form form View source History View New Pages Recent Changes All Special Pages Semantic Search/Querying Get Involved Help Apps Datasets Community Login | Sign Up Search Page Edit with form History Facebook icon Twitter icon » Rock Density Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Rock Density Details Activities (2) Areas (2) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Lab Analysis Techniques Exploration Sub Group: Rock Lab Analysis Parent Exploration Technique: Rock Lab Analysis Information Provided by Technique Lithology: Density of different lithologic units. Stratigraphic/Structural: Hydrological: Thermal: Cost Information Low-End Estimate (USD): 10.001,000 centUSD 0.01 kUSD 1.0e-5 MUSD 1.0e-8 TUSD / sample

300

Comparing Optical and Near Infrared Luminosity Functions  

E-Print Network (OSTI)

The Sloan Digital Sky Survey [SDSS] has measured an optical luminosity function for galaxies in 5 bands, finding 1.5 to 2.1 times more luminosity density than previous work. This note compares the SDSS luminosity density to two recent determinations of the near infrared luminosity function based on 2MASS data, and finds that an extrapolation of the SDSS results gives a 2.3 times greater near infrared luminosity density.

Edward L. Wright

2001-02-02T23:59:59.000Z

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


301

Plasma digital density determining device  

DOE Patents (OSTI)

The density of a decaying plasma in an electrically conducting enclosure is determined by applying an excitation to the cavity formed by the enclosure and counting digitally the number of resonant frequencies traversed by the combination of the cavity and the decaying plasma.

Sprott, Julien C. (Madison, WI); Lovell, Thomas W. (Madison, WI); Holly, Donald J. (Madison, WI)

1976-01-01T23:59:59.000Z

302

Density-permittivity relationships for powdered and granular materials  

SciTech Connect

Relationships between the permittivities of powdered or granular solid materials and their bulk densities (density of the air-particle mixture) are discussed. Linear relationships between functions of the permittivity and bulk density are identified that are useful in determining permittivity of solids from measurements of the permittivity of pulverized samples. The usefulness of several dielectric mixture equations for calculating solid material permittivity from measured permittivity of pulverized samples is also discussed. Results of testing linear extrapolation techniques and dielectric mixture equations on pulverized coal, limestone, plastics, and granular wheat and flour are presented. Recommendations are provided for reliable estimation of solid material permittivities or changes in permittivities of powdered and granular materials as a result of changes in their bulk densities.

Nelson, S.O. [USDA ARS, Athens, GA (United States). Russell Research Center

2005-10-01T23:59:59.000Z

303

Magnetic Method to Characterize the Current Densities in Breaker Arc  

Science Conference Proceedings (OSTI)

The purpose of this research was to use magnetic induction measurements from a low voltage breaker arc, to reconstruct the arc's current density. The measurements were made using Hall effect sensors, which were placed close to, but outside the breaking device. The arc was modelled as a rectangular current sheet, composed of a mix of threadlike current segments and with a current density varying across the propagation direction. We found the magnetic induction of the arc is a convolution product of the current density, and a function depending on the breaker geometry and arc model. Using deconvolution methods, the current density in the electric arc was determined.The method is used to study the arc behavior into the breaker device. Notably, position, arc size, and electric conductivity could all be determined, and then used to characterize the arc mode, diffuse or concentrated, and study the condition of its mode changing.

Machkour, Nadia [National Institute of Standards and Technology (United States)

2005-04-15T23:59:59.000Z

304

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

E-Print Network (OSTI)

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

Goldman, Steven A.

305

Densities and energies of nuclei in dilute matter  

E-Print Network (OSTI)

We explore the ground-state properties of nuclear clusters embedded in a gas of nucleons with the help of Skyrme-Hartree-Fock microscopic calculations. Two alternative representations of clusters are introduced, namely coordinate-space and energy-space clusters. We parameterize their density profiles in spherical symmetry in terms of basic properties of the energy density functionals used and propose an analytical, Woods-Saxon density profile whose parameters depend, not only on the composition of the cluster, but also of the nucleon gas. We study the clusters' energies with the help of the local-density approximation, validated through our microscopic results. We find that the volume energies of coordinate-space clusters are determined by the saturation properties of matter, while the surface energies are strongly affected by the presence of the gas. We conclude that both the density profiles and the cluster energies are strongly affected by the gas and discuss implications for the nuclear EoS and related perspectives. Our study provides a simple, but microscopically motivated modeling of the energetics of clusterized matter at subsaturation densities, for direct use in consequential applications of astrophysical interest.

P. Papakonstantinou; J. Margueron; F. Gulminelli; Ad. R. Raduta

2013-05-01T23:59:59.000Z

306

Generalized One-Particle Density Matrices and Quasifree States  

E-Print Network (OSTI)

In the spirit of the generalized one-particle density matrix for fermions, we introduce generalized one- and two-particle density matrices to state representability conditions up to second order for boson systems without assuming particle number-conservation. Furthermore, we show for both particle species that, for a semibounded Hamiltonian, the in?mum of the variation of the energy functional w.r.t quasifree states coincides with the one of a variation over pure quasifree states. Moreover, it is proven for fermions that only pure quasifree states have a generalized 1-pdm that is a projection, and a similar statement for bosons.

Volker Bach; Sébastien Breteaux; Hans Konrad Knörr; Edmund Menge

2013-04-30T23:59:59.000Z

307

DENSITY CONTROL IN A REACTOR  

DOE Patents (OSTI)

A reactor is described in which natural-uranium bodies are located in parallel channels which extend through the graphite mass in a regular lattice. The graphite mass has additional channels that are out of the lattice and contain no uranium. These additional channels decrease in number per unit volume of graphite from the center of the reactor to the exterior and have the effect of reducing the density of the graphite more at the center than at the exterior, thereby spreading neutron activity throughout the reactor. (AEC)

Marshall, J. Jr.

1961-10-24T23:59:59.000Z

308

Definition: Power density | Open Energy Information  

Open Energy Info (EERE)

density density Jump to: navigation, search Dictionary.png Power density The rate of energy flow (power) per unit volume, area or mass. Common metrics include: horsepower per cubic inch, watts per square meter and watts per kilogram.[1][2] View on Wikipedia Wikipedia Definition Power density (or volume power density or volume specific power) is the amount of power (time rate of energy transfer) per unit volume. In energy transformers like batteries, fuel cells, motors, etc. but also power supply units or similar, power density refers to a volume. It is then also called volume power density which is expressed as W/m. Volume power density is sometimes an important consideration where space is constrained. In reciprocated internal combustion engines, power density- power per swept

309

Phase diagram of amorphous solid water: Low-density, high-density, and very-high-density amorphous ices  

E-Print Network (OSTI)

for the understanding of the transformation between the different amorphous ices and the two hypothesized phasesPhase diagram of amorphous solid water: Low-density, high-density, and very-high-density amorphous ices Nicolas Giovambattista,1,2 H. Eugene Stanley,2 and Francesco Sciortino3 1 Department of Chemical

Sciortino, Francesco

310

Regression based D-optimality experimental design for sparse kernel density estimation  

Science Conference Proceedings (OSTI)

This paper derives an efficient algorithm for constructing sparse kernel density (SKD) estimates. The algorithm first selects a very small subset of significant kernels using an orthogonal forward regression (OFR) procedure based on the D-optimality ... Keywords: D-optimality, Optimal experimental design, Orthogonal forward regression, Parzen window estimate, Probability density function, Sparse kernel modelling

S. Chen; X. Hong; C. J. Harris

2010-01-01T23:59:59.000Z

311

Refractive index and density in F- and Cl-doped silica glasses  

Science Conference Proceedings (OSTI)

The refractive index and density of fluorine- and chlorine-doped silica glasses were measured as functions of fictive temperature. The halogen concentrations were observed to have a refractive index or density that is independent of the fictive temperature were found. This implies that these properties are not affected by any heat-treatment conditions.

Kakiuchida, Hiroshi; Shimodaira, Noriaki; Sekiya, Edson H.; Saito, Kazuya; Ikushima, Akira J. [Research Center for Advanced Photon Technology, Toyota Technological Institute, 2-12-1 Hisakata, Tempaku, Nagoya, Aichi 468-8511 (Japan); Research Center for Advanced Photon Technology, Toyota Technological Institute, 2-12-1 Hisakata, Tempaku, Nagoya, Aichi 468-8511, Japan and Research Center, Asahi Glass Co., Ltd., 1150 Hazawa-cho, Kanagawa, Yokohama, Kanagawa 221-8755 (Japan); Research Center for Advanced Photon Technology, Toyota Technological Institute, 2-12-1 Hisakata, Tempaku, Nagoya, Aichi 468-8511 (Japan)

2005-04-18T23:59:59.000Z

312

Oxides having high energy densities  

DOE Patents (OSTI)

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.

Ceder, Gerbrand; Kang, Kisuk

2013-09-10T23:59:59.000Z

313

Risk Bounds for Mixture Density Estimation  

E-Print Network (OSTI)

In this paper we focus on the problem of estimating a bounded density using a finite combination of densities from a given class. We consider the Maximum Likelihood Procedure (MLE) and the greedy procedure described by ...

Rakhlin, Alexander

2004-01-27T23:59:59.000Z

314

The Intrusion Depth of Density Currents Flowing into Stratified Water Bodies  

Science Conference Proceedings (OSTI)

Theory and laboratory experiments are presented describing the depth at which a density current intrudes into a linearly stratified water column, as a function of the entrainment ratio E, the buoyancy flux in the dense current B, and the ...

Mathew Wells; Parthiban Nadarajah

2009-08-01T23:59:59.000Z

315

Transport Energy Use and Population Density  

NLE Websites -- All DOE Office Websites (Extended Search)

Transport Energy Use and Population Density Transport Energy Use and Population Density Speaker(s): Masayoshi Tanishita Date: July 1, 2004 - 10:00pm Location: Bldg. 90 Seminar Host/Point of Contact: Jonathan Sinton After Peter Newman and Jeffrey Kenworthy published "Cities and Automobile Dependence" in 1989, population density was brought to public attention as an important factor to explain transport mobility and energy use. However, several related issues still remain open: Is an increase in population density more effective than rising gas prices in reducing transport energy use? How much does per capita transport energy use change as population density in cities changes? And what kind of factors influence changes in population density? In this presentation, using city-level data in the US, Japan and other countries, the population-density elasticity of

316

Density matrix, superconductivity and molecular structure  

Science Conference Proceedings (OSTI)

Starting from Yang`s offdiagonal long-range order concept and the macroscopic occupation condition for the second order density matrix as the basis for condensation phenomena the authors develop the notion that the extremal wave function (EWF), which is related to these conditions, leads to superconductivity in monatomic systems. It is proven that the BCS model and the version where it is projected onto a fixed number of particles possesses EWF properties, differs negligibly from the EWF, and conserves offdiagonal long-range order. The condition for the EWF to be energetically favored is the presence of macroscopic degenerate one-electron energy levels in the system, partial occupation of this degenerate region, and also an effective attraction among the electrons. Considerations are advanced indicating that these conditions are satisfied in the high temperature superconducting metal oxide ceramics, due to the presence of macroscopically degenerate diffusion orbitals distributed among the O{sup -} ions in the CuO{sub 2} layers, and with the effective screening of these layers by the metal-like La, Ba, Y, or O layers. 51 refs., 3 figs., 1 tab.

Mestechkin, M.M.; Klimko, G.T.; Vaiman, G.E. [Academy of Science of the Ukrainian SSR, Donetsk (Russian Federation)

1992-01-01T23:59:59.000Z

317

LA-101( ' X I -E N V~ E N V I R O N M E N T A LS U R V E I L L AA -L O. A -L A -MD U R  

E-Print Network (OSTI)

LA-101( ' X I - E N V~ E N V I R O N M E N T A LS U R V E I L L AA - &.' L_ .---. L O. A - L A - MD U R ,. ,, .". ... , . 1 ` - : . , .i * ?. .& x ` "E!E7...';: s ---- --. -- - + 4. -- sA l a m oN a t i oL a b o r L oA l a m o sN eM e x8 7 `"'l~@fO,,J~@jj~~~~.F=~Of.f~n~~~Y. - w

318

Functional Specifications  

NLE Websites -- All DOE Office Websites (Extended Search)

Functional Specifications Functional Specifications Services Overview ECS Audio/Video Conferencing Fasterdata IPv6 Network Network Performance Tools (perfSONAR) ESnet OID Registry PGP Key Service Virtual Circuits (OSCARS) OSCARS Case Study Documentation User Manual FAQ Design Specifications Functional Specifications Notifications Publications Authorization Policy Default Attributes Message Security Clients For Developers Interfaces Links Hardware Requirements DOE Grids Service Transition Contact Us Technical Assistance: 1 800-33-ESnet (Inside the US) 1 800-333-7638 (Inside the US) 1 510-486-7600 (Globally) 1 510-486-7607 (Globally) Report Network Problems: trouble@es.net Provide Web Site Feedback: info@es.net Functional Specifications OSCARS Reservation Manager - Functional Specifications Year 3 Update (DRAFT)

319

THE COLUMN DENSITY VARIANCE-M{sub s} RELATIONSHIP  

SciTech Connect

Although there is a wealth of column density tracers for both the molecular and diffuse interstellar medium, there are few observational studies investigating the relationship between the density variance ({sigma}{sup 2}) and the sonic Mach number (M{sub s}). This is in part due to the fact that the {sigma}{sup 2}-M{sub s} relationship is derived, via MHD simulations, for the three-dimensional (3D) density variance only, which is not a direct observable. We investigate the utility of a 2D column density {sigma}{sub {Sigma}/{Sigma}0}{sup 2}-M{sub s} relationship using solenoidally driven isothermal MHD simulations and find that the best fit follows closely the form of the 3D density {sigma}{sub {rho}/{rho}0}{sup 2}-M{sub s} trend but includes a scaling parameter A such that {sigma}{sub ln({Sigma}/{Sigma}o)} = A x ln(1+b{sup 2} M{sub s}{sup 2}), where A = 0.11 and b = 1/3. This relation is consistent with the observational data reported for the Taurus and IC 5146 molecular clouds with b = 0.5 and A = 0.16, and b = 0.5 and A = 0.12, respectively. These results open up the possibility of using the 2D column density values of {sigma}{sup 2} for investigations of the relation between the sonic Mach number and the probability distribution function (PDF) variance in addition to existing PDF sonic Mach number relations.

Burkhart, Blakesley; Lazarian, A. [Astronomy Department, University of Wisconsin, Madison, 475 N. Charter St., WI 53706 (United States)

2012-08-10T23:59:59.000Z

320

High Density Fuel Development for Research Reactors  

SciTech Connect

An international effort to develop, qualify, and license high and very high density fuels has been underway for several years within the framework of multi-national RERTR programs. The current development status is the result of significant contributions from many laboratories, specifically CNEA in Argentina, AECL in Canada, CEA in France, TUM in Germany, KAERI in Korea, VNIIM, RDIPE, IPPE, NCCP and RIARR in Russia, INL, ANL and Y-12 in USA. These programs are mainly engaged with UMo dispersion fuels with densities from 6 to 8 gU/cm3 (high density fuel) and UMo monolithic fuel with density as high as 16 gU/cm3 (very high density fuel). This paper, mainly focused on the French & US programs, gives the status of high density UMo fuel development and perspectives on their qualification.

Daniel Wachs; Dennis Keiser; Mitchell Meyer; Douglas Burkes; Curtis Clark; Glenn Moore; Jan-Fong Jue; Totju Totev; Gerard Hofman; Tom Wiencek; Yeon So Kim; Jim Snelgrove

2007-09-01T23:59:59.000Z

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


321

The Quantum Energy Density: Improved E  

Science Conference Proceedings (OSTI)

We establish a physically meaningful representation of a quantum energy density for use in Quantum Monte Carlo calculations. The energy density operator, dened in terms of Hamiltonian components and density operators, returns the correct Hamiltonian when integrated over a volume containing a cluster of particles. This property is demonstrated for a helium-neon \\gas," showing that atomic energies obtained from the energy density correspond to eigenvalues of isolated systems. The formation energies of defects or interfaces are typically calculated as total energy dierences. Using a model of delta-doped silicon (where dopant atoms form a thin plane) we show how interfacial energies can be calculated more eciently with the energy density, since the region of interest is small. We also demonstrate how the energy density correctly transitions to the bulk limit away from the interface where the correct energy is obtainable from a separate total energy calculation.

Krogel, Jaron [University of Illinois, Urbana-Champaign; Yu, Min [Lawrence Berkeley National Laboratory (LBNL); Kim, Jeongnim [ORNL; Ceperley, David M. [University of Illinois, Urbana-Champaign

2013-01-01T23:59:59.000Z

322

Dynamic Evolution for Risk-Neutral Densities  

E-Print Network (OSTI)

We solved the scaled formulation for problems (7) and (10) and obtained the dynamic evolution for the densities (see Figure 1). For this data set, we.

323

Application of Precession Electron Diffraction in Density ...  

Science Conference Proceedings (OSTI)

In this paper, GND density calculations obtained using SEM-based EBSD and transmission electron microscope-based PED techniques in ?+? titanium alloys ...

324

MECHANICALLY ROBUST, ELECTRICALLY CONDUCTIVE ULTRALOW-DENSITY ...  

A method of making a mechanically robust, electrically conductive ultralow-density carbon nanotube-based aerogel, including the steps of dispersing nanotubes in an ...

325

Betatron radiation from density tailored plasmas  

E-Print Network (OSTI)

Betatron radiation from density tailored plasmas K. Tathe resulting betatron radiation spectrum can therefore bepro?le, the betatron radiation emitted by theses electrons

Ta Phuoc, Kim

2010-01-01T23:59:59.000Z

326

3-D capacitance density imaging system  

DOE Patents (OSTI)

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.

Fasching, G.E.

1988-03-18T23:59:59.000Z

327

High Energy Density Secondary Lithium Batteries  

High Energy Density Secondary Lithium Batteries Note: The technology described above is an early stage opportunity. Licensing rights to this intellectual property may

328

FOAM DENSITY SENSITIVITY STUDY FOR THE 9977 PACKAGE  

SciTech Connect

Two layers of insulation fill the volume of the 9977 package between the drum liner and the shell. One of these layers is composed of General Plastics FR-3716 polyurethane foam (also known as Last-A-Foam{reg_sign}), poured through fill holes in the drum bottom and foamed in place. There was concern that the density of the foam insulating layer may vary due to the manufacturing process and that variations in foam density would compromise the safety basis of the package. Thus, a structural finite element analysis was performed to investigate this concern. The investigation examined the effect of replacing the material properties for the FR-3716 polyurethane foam, which has a density equal to 16 lb{sub m}/ft{sup 3}, with material properties of similar foam with varying densities through finite element analysis of hypothetical accident conditions (HAC) pertaining to impact conditions. The results showed that the functional performance of the containment vessel (CV) was not compromised under the conditions investigated.

Gorczyca, J; Tsu-Te Wu, T

2008-05-02T23:59:59.000Z

329

DFT-based molecular dynamics as a new tool for computational biology: first applications and perspective  

Science Conference Proceedings (OSTI)

Static and molecular dynamics (MD) calculations based on density-functional theory (DFT) are emerging as a valuable means for simulations in the field of biology, especially when coupled with classical simulations. In this contribution, we point out ...

W. Andreoni; A. Curioni; T. Mordasini

2001-05-01T23:59:59.000Z

330

Part Functions  

Science Conference Proceedings (OSTI)

Table 1   Functions served by parts...Mechanical power Shafts, connecting rods, gears Electricity Wires, lightbulb elements, resistors Provide a barrier (for example: reflect, cover, enclose,

331

Functional quantization  

E-Print Network (OSTI)

Data is rarely obtained for its own sake; oftentimes, it is a function of the data that we care about. Traditional data compression and quantization techniques, designed to recreate or approximate the data itself, gloss ...

Misra, Vinith

2008-01-01T23:59:59.000Z

332

Density-based Energy Decomposition Analysis for Intermolecular Interactions with Variationally Determined Intermediate State Energies  

DOE Green Energy (OSTI)

The first purely density-based energy decomposition analysis (EDA) for intermolecular binding is developed within the density functional theory. The most important feature of this scheme is to variationally determine the frozen density energy, based on a constrained search formalism and implemented with the Wu-Yang algorithm [Q. Wu and W. Yang, J. Chem. Phys. 118, 2498 (2003) ]. This variational process dispenses with the Heitler-London antisymmetrization of wave functions used in most previous methods and calculates the electrostatic and Pauli repulsion energies together without any distortion of the frozen density, an important fact that enables a clean separation of these two terms from the relaxation (i.e., polarization and charge transfer) terms. The new EDA also employs the constrained density functional theory approach [Q. Wu and T. Van Voorhis, Phys. Rev. A 72, 24502 (2005)] to separate out charge transfer effects. Because the charge transfer energy is based on the density flow in real space, it has a small basis set dependence. Applications of this decomposition to hydrogen bonding in the water dimer and the formamide dimer show that the frozen density energy dominates the binding in these systems, consistent with the noncovalent nature of the interactions. A more detailed examination reveals how the interplay of electrostatics and the Pauli repulsion determines the distance and angular dependence of these hydrogen bonds.

Wu, Q.; Ayers, P.W.; Zhang, Y.

2009-10-28T23:59:59.000Z

333

The elusive middle domain of Hsp104 and ClpB: Location and function Morgan E. DeSantis a,b  

E-Print Network (OSTI)

of the individual domains was largely resolved in 2003 when a 3.0 Ă? crystal structure of ClpB (TClpB) from of this review, we have provided a unified nomenclature to describe regions of the MD in ClpB, TClpB, and Hsp104% identity. Unfortunately, full-length TClpB did not crystallize in its functional hexameric structure

Shorter, James

334

The elusive middle domain of Hsp104 and ClpB: Location and function Morgan E. DeSantis a,b  

E-Print Network (OSTI)

domains was largely resolved in 2003 when a 3.0 Ă? crystal structure of ClpB (TClpB) from the thermophilic of this review, we have provided a unified nomenclature to describe regions of the MD in ClpB, TClpB, and Hsp104% identity. Unfortunately, full-length TClpB did not crystallize in its functional hexameric structure

Shorter, James

335

High density laser-driven target  

DOE Patents (OSTI)

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.

Lindl, John D. (San Ramon, CA)

1981-01-01T23:59:59.000Z

336

Laser light absorption with density profile modifications  

SciTech Connect

Two-dimensional computer simulations studied plasma heating by electron plasma waves. The results emphasize the importance of nonlinear steepening of the density profile near the critical density. A typical simulation result is presented in order to illustrate these profile modifications. It is shown that large dc magnetic field generation is an inherent property of the absorption of obliquely-incident light. (MOW)

Kruer, W.; Valeo, E.; Estabrook, K.; Langdon, B.; Lasinski, B.

1974-12-01T23:59:59.000Z

337

Density of Spray-Formed Materials  

SciTech Connect

Spray Forming is an advanced materials processing technology that transforms molten metal into a near-net-shape solid by depositing atomized droplets onto a substrate. Depending on the application, the spray-formed material may be used in the as-deposited condition or it may undergo post-deposition processing. Regardless, the density of the as-deposited material is an important issue. Porosity is detrimental because it can significantly reduce strength, toughness, hardness and other properties. While it is not feasible to achieve fully-dense material in the as-deposited state, density greater than 99% of theoretical density is possible if the atomization and impact conditions are optimized. Thermal conditions at the deposit surface and droplet impact angle are key processing parameters that influence the density of the material. This paper examines the factors that contribute to porosity formation during spray forming and illustrates that very high as-deposited density is achieved by optimizing processing parameters.

Kevin M. McHugh; Volker Uhlenwinkel; Nils Ellendr

2008-06-01T23:59:59.000Z

338

Electrostatic lens to focus an ion beam to uniform density  

SciTech Connect

A focusing lens for an ion beam having a gaussian or similar density profile is provided. The lens is constructed to provide an inner zero electrostatic field, and an outer electrostatic field such that ions entering this outer field are deflected by an amount that is a function of their distance from the edge of the inner field. The result is a beam that focuses to a uniform density in a manner analogous to that of an optical ring lens. In one embodiment, a conically-shaped network of fine wires is enclosed within a cylindrical anode. The wire net together with the anode produces a voltage field that re-directs the outer particles of the beam while the axial particles pass undeflected through a zero field inside the wire net. The result is a focused beam having a uniform intensity over a given target area and at a given distance from the lens.

Johnson, Cleland H. (Oak Ridge, TN)

1977-01-11T23:59:59.000Z

339

Classical Phase Space Density for the Relativistic Hydrogen Atom  

E-Print Network (OSTI)

Quantum mechanics is considered to arise from an underlying classical structure (``hidden variable theory'', ``sub-quantum mechanics''), where quantum fluctuations follow from a physical noise mechanism. The stability of the hydrogen ground state can then arise from a balance between Lorentz damping and energy absorption from the noise. Since the damping is weak, the ground state phase space density should predominantly be a function of the conserved quantities, energy and angular momentum. A candidate for this phase space density is constructed for ground state of the relativistic hydrogen problem of a spinless particle. The first excited states and their spherical harmonics are also considered in this framework. The analytic expression of the ground state energy can be reproduced, provided averages of certain products are replaced by products of averages. This analysis puts forward that quantum mechanics may arise from an underlying classical level as a slow variable theory, where each new quantum operator relates to a new, well separated time interval.

Th. M. Nieuwenhuizen

2005-11-15T23:59:59.000Z

340

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

Science Conference Proceedings (OSTI)

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.

Wang, Tianjiao

2008-12-01T23:59:59.000Z

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


341

Density fingering in spatially modulated Hele-Shaw cells  

SciTech Connect

Density fingering of the chlorite-tetrathionate reaction has been studied experimentally in a periodically heterogeneous Hele-Shaw cell where the heterogeneity is introduced in the form of spatial modulation of gap width along the front. Depending on the spatial wavelength, gap width, and chemical composition, three types of cellular structures have been observed. The initial evolution is characterized by dispersion curves, while the long time behavior is described by the change in the autocorrelation function of the front profile and in the mixing length of the patterns.

Toth, Tamara; Horvath, Dezso; Toth, Agota [Department of Physical Chemistry, University of Szeged, P.O. Box 105, Szeged, H-6701 (Hungary)

2007-12-21T23:59:59.000Z

342

Sub-barrier Fusion Cross Sections with Energy Density Formalism  

E-Print Network (OSTI)

We discuss the applicability of the energy density formalism (EDF) for heavy-ion fusion reactions at sub-barrier energies. For this purpose, we calculate the fusion excitation function and the fusion barrier distribution for the reactions of $^{16}$O with $^{154,}$$^{144}$Sm,$^{186}$W and $^{208}$Pb with the coupled-channels method. We also discuss the effect of saturation property on the fusion cross section for the reaction between two $^{64}$Ni nuclei, in connection to the so called steep fall-off phenomenon of fusion cross sections at deep sub-barrier energies.

F. Muhammad Zamrun; K. Hagino; N. Takigawa

2006-06-07T23:59:59.000Z

343

wave power density | OpenEI  

Open Energy Info (EERE)

power density power density Dataset Summary Description This project estimates the naturally available and technically recoverable U.S. wave energy resources, using a 51-month Wavewatch III hindcast database developed especially for this study by National Oceanographic and Atmospheric Administration's (NOAA's) National Centers for Environmental Prediction. For total resource estimation, wave power density in terms of kilowatts per meter is aggregated across a unit diameter circle. Source Electric Power Research Institute (EPRI) Date Released December 05th, 2011 (2 years ago) Date Updated Unknown Keywords EPRI MHK NREL ocean Virginia Tech wave wave power density Data application/pdf icon Download Full Report (pdf, 8.8 MiB) Quality Metrics Level of Review Some Review Comment

344

Definition: Rock Density | Open Energy Information  

Open Energy Info (EERE)

in crustal rocks. Rock density is a physical characteristic that is governed by the chemical composition (in situ minerals) and pore spaces of a specific rock or rock type.1...

345

High density load bearing insulation peg  

DOE Patents (OSTI)

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.

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

1985-01-29T23:59:59.000Z

346

Density controlled carbon nanotube array electrodes  

DOE Patents (OSTI)

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.

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

2008-12-16T23:59:59.000Z

347

Separation of carbon nanotubes in density gradients  

DOE Patents (OSTI)

The separation of single-walled carbon nanotubes (SWNTs), by chirality and/or diameter, using centrifugation of compositions of SWNTs in and surface active components in density gradient media.

Hersam, Mark C. (Evanston, IL); Stupp, Samuel I. (Chicago, IL); Arnold, Michael S. (Northbrook, IL)

2012-02-07T23:59:59.000Z

348

Separation of carbon nanotubes in density gradients  

DOE Patents (OSTI)

The separation of single-walled carbon nanotubes (SWNTs), by chirality and/or diameter, using centrifugation of compositions of SWNTs in and surface active components in density gradient media.

Hersam, Mark C. (Evanston, IL); Stupp, Samuel I. (Chicago, IL); Arnold, Michael S. (Northbrook, IL)

2010-02-16T23:59:59.000Z

349

High density load bearing insulation peg  

DOE Patents (OSTI)

A high density peg 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.

Nowobilski, Jeffert J. (Orchard Park, NY); Owens, William J. (Kenmore, NY)

1985-01-01T23:59:59.000Z

350

Support for the delisting of decontaminated liquid chemical surety materials as listed hazardous waste from specific sources (state) MD02 in COMAR 10. 51. 02. 16-1. Technical report, December 1987-February 1988  

SciTech Connect

Maryland recently enacted regulations that listed decontaminated residues of certain chemical warfare agents as hazardous wastes. The State would consider delisting if the Army document the effects of its decontamination procedures. Army specialists at U.S. Army Chemical Research, Development and Engineering Center (CRDEC), Aberdeen Proving Ground, MD, have had exhaustive experience in this area since 1918 when chemical agents were first used in combat in World War I. Competence accrued during this 70-year legacy includes destruction of laboratory and training wastes, combat decontamination, and largescale demilitarization of unserviceable and obsolete agent-filled munitions. The facts and circumstances enumerated in this document indicate that current decontamination practices are safe, scientifically valid, and result in the total destruction of agents in questions.

Durst, H.D.; Sarver, E.W.; Yurow, H.W.; Beaudry, W.T.; D'Eramo, P.A.

1988-11-01T23:59:59.000Z

351

Aging and functional brain networks  

SciTech Connect

Aging is associated with changes in human brain anatomy and function and cognitive decline. Recent studies suggest the aging decline of major functional connectivity hubs in the 'default-mode' network (DMN). Aging effects on other networks, however, are largely unknown. We hypothesized that aging would be associated with a decline of short- and long-range functional connectivity density (FCD) hubs in the DMN. To test this hypothesis, we evaluated resting-state data sets corresponding to 913 healthy subjects from a public magnetic resonance imaging database using functional connectivity density mapping (FCDM), a voxelwise and data-driven approach, together with parallel computing. Aging was associated with pronounced long-range FCD decreases in DMN and dorsal attention network (DAN) and with increases in somatosensory and subcortical networks. Aging effects in these networks were stronger for long-range than for short-range FCD and were also detected at the level of the main functional hubs. Females had higher short- and long-range FCD in DMN and lower FCD in the somatosensory network than males, but the gender by age interaction effects were not significant for any of the networks or hubs. These findings suggest that long-range connections may be more vulnerable to aging effects than short-range connections and that, in addition to the DMN, the DAN is also sensitive to aging effects, which could underlie the deterioration of attention processes that occurs with aging.

Tomasi D.; Tomasi, D.; Volkow, N.D.

2011-07-11T23:59:59.000Z

352

Hydrogenation and surface density changes in hydrocarbon films during erosion using Ar/H{sub 2} plasmas  

SciTech Connect

We report interactions of low pressure Ar, H{sub 2}, and Ar/H{sub 2} mixture plasmas with a-C:H films. Surface evolution and erosion of a-C:H films were examined for ion energies up to 200 eV by rf biasing the substrates. Film surfaces were characterized using in situ ellipsometry, x-ray photoelectron spectroscopy, and atomic force microscopy. Multilayer models for steady-state modified surface layers are constructed using ellipsometric data and compared with results of molecular dynamics (MD) simulations and transport of ions in matter (TRIM) calculations. We find that Ar plasma causes a modified layer at the surface that is depleted of H atoms. The depth and degree of this modification is strongly depending on Ar ion energies. This depletion saturates quickly during plasma exposure (<1 s) and persists during steady-state erosion. We find that the thickness and density of the H-depleted layer are in good agreement with MD and TRIM simulations. The degree of surface densification decreases when small amounts of H{sub 2} are added to Ar plasmas. When more than 5% H{sub 2} is added to the plasma, long term loss in surface density is observed, indicating rehydrogenation and saturation of H in the film. As the H{sub 2} fraction increases, the near-surface atomic H increases and the ion composition bombarding the surface changes. This causes incorporation of H deeper into the a-C:H film. For a-C:H films exposed to pure H{sub 2} plasmas, H is introduced into the near-surface region to a depth of up to {approx}8 nm from the surface. As the rf bias is increased the ion energy transitions from solely chemical sputtering to one involving physical sputtering, causing the yield of C atoms from the surface to greatly increase. The increasing yield suppresses H incorporation/saturation and decreases the magnitude of the modified surface layer.

Fox-Lyon, N.; Oehrlein, G. S. [Department of Materials Science and Engineering and Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742 (United States); Ning, N.; Graves, D. B. [Department of Chemical Engineering, University of California, Berkeley, California 94720 (United States)

2011-11-15T23:59:59.000Z

353

Beyond the Gas Phase: Towards Modeling Bulk Ionic Liquids with a Comparison of Density Functional Tight Binding (DFTB) to Density Functional Theory (DFT).  

E-Print Network (OSTI)

??Coal-fired power plants are a leading contributor to the increase in CO2 released into the atmosphere. Alkanolamines are considered a potential solvent to capture this… (more)

Danser, Mandelle Ann

2010-01-01T23:59:59.000Z

354

Evaluating the transferability of coarse-grained, density-dependent implicit solvent models to mixtures and chains  

E-Print Network (OSTI)

Previously, we described a coarse-graining method for creating local density-dependent implicit solvent (DDIS) potentials that reproduce the radial distribution function (RDF) and solute excess chemical potential across a ...

Allen, Erik C.

355

Shell model transition densities for electron and pion scattering  

Science Conference Proceedings (OSTI)

The general features of an effective interaction suitable for the calculation of cross-shell matrix elements in the /sup 16/O region are discussed. Shell-model transition densities are applied to the 1 hw excitation of non-normal parity states in light-nuclei, with /sup 13/C used as a prime example. The longitudinal form factors from such a calculation require enhancement and transverse form factors (spin-excitations) need to be quenched. The shapes of form factors also exhibit systematic discrepancies which are correlated with the discrepancies in magnitude. The problem with shapes is particularly marked for C1 form factors. It is shown that the addition of small components to the transition density, corresponding to the excitation of a single particle through two or three major shells, works in the right direction as far as both magnitude and shape are concerned and that such additions are particularly effective in the case of C1 excitations. For the transverse form factors in /sup 13/C, the use of Woods-Saxon radial wave functions leads to reductions of up to 50% compared with harmonic oscillator wave functions. The excitation of states with dominant multiparticle-multihole components, and the role played by admixtures of such configurations in low-lying states, is considered. Some of the problems associated with the use of shell-model bases extended to include high-lying configurations in the giant resonance region are pointed out. 15 refs., 15 figs., 1 tab.

Millener, D.J.

1987-01-01T23:59:59.000Z

356

The Evolution of Stellar Mass Density and its Implied Star Formation History  

E-Print Network (OSTI)

Using a compilation of measurements of the stellar mass density as a function of redshift we can infer the cosmic star formation history. For z histories. At higher redshifts the instantaneous indicators suggest star formation rates larger than that implied by the evolution of the stellar mass density. This discrepancy peaks at z = 3 where instantaneous indicators suggest a star formation rate around 0.6 dex higher than those of the best fit to the stellar mass history. We discuss a variety of explanations for this inconsistency, such as inaccurate dust extinction corrections, incorrect measurements of stellar masses and a possible evolution of the stellar initial mass function.

S. M. Wilkins; N. Trentham; A. M. Hopkins

2008-03-27T23:59:59.000Z

357

Density logging and density of rocks in Rainier Mesa Area, Nevada Test Site  

SciTech Connect

Density logs from all 35 vertical drill holes in the Rainier Mesa area in which logs were obtained were evaluated and the distribution of densities of units in the geologic section was derived. Densities were obtained in only 10 holes in which calibrated logging tools had been run. The logs from an additional 10 holes were calibrated with core. Densities vary from nearly 1 g/cc in tunnel bed 5 to over 2.8 g/cc in the dolomitic rocks. Log densities were found to agree well with core data in those subunits (chiefly within tunnel beds 3 and 4) where an adequate number of core measurements were available for comparison. Lithologic correlations based on density log signatures were found to extend for more than 8 km in several units and subunits in the area. Although the volcanic rocks in the Rainier Mesa area are comprised of a wider spectrum of minerals than the petroliferous rocks generally involved in most commercial logging applications, grain density may be estimated with good accuracy with only a knowledge of glass and zeolite content. The variability of the Z/A ratio of the matrix in these volcanic rocks is also negligible compared to the value of 0.5 generally assumed in density logging. However, due to the assumptions made concerning the Z/A of water in deriving the output of commercial density tools, one should be aware of the errors inherent in assuming that recorded log densities are true densities. These errors are normally small, being less than 3 percent for compensated limestone'' tools and 2 percent for tools which output electron density. 35 refs., 25 figs., 12 tabs.

Carroll, R.D.

1989-01-01T23:59:59.000Z

358

Spin and the Thermal Equilibrium Distribution of Wave Functions  

E-Print Network (OSTI)

Consider a quantum system $S$ weakly interacting with a very large but finite system $B$ called the heat bath, and suppose that the composite $S\\cup B$ is in a pure state $\\Psi$ with participating energies between $E$ and $E+\\delta$ with small $\\delta$. Then, it is known that for most $\\Psi$ the reduced density matrix of $S$ is (approximately) equal to the canonical density matrix. That is, the reduced density matrix is universal in the sense that it depends only on $S$'s Hamiltonian and the temperature but not on $B$'s Hamiltonian, on the interaction Hamiltonian, or on the details of $\\Psi$. It has also been pointed out that $S$ can also be attributed a random wave function $\\psi$ whose probability distribution is universal in the same sense. This distribution is known as the "Scrooge measure" or "Gaussian adjusted projected (GAP) measure"; we regard it as the thermal equilibrium distribution of wave functions. The relevant concept of the wave function of a subsystem is known as the "conditional wave function". In this paper, we develop analogous considerations for particles with spin. One can either use some kind of conditional wave function or, more naturally, the "conditional density matrix", which is in general different from the reduced density matrix. We ask what the thermal equilibrium distribution of the conditional density matrix is, and find the answer that for most $\\Psi$ the conditional density matrix is (approximately) deterministic, in fact (approximately) equal to the canonical density matrix.

Viraj Pandya; Roderich Tumulka

2013-06-07T23:59:59.000Z

359

Precise and Accurate Density Determination of Explosives Using Hydrostatic Weighing  

SciTech Connect

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.

B. Olinger

2005-07-01T23:59:59.000Z

360

High-Energy-Density Plasmas, Fluids  

NLE Websites -- All DOE Office Websites (Extended Search)

High-Energy-Density Plasmas, Fluids High-Energy-Density Plasmas, Fluids /science-innovation/_assets/images/icon-science.jpg High-Energy-Density Plasmas, Fluids National security depends on science and technology. The United States relies on Los Alamos National Laboratory for the best of both. No place on Earth pursues a broader array of world-class scientific endeavors. TRIDENT target chamber Sasi Palaniyappan, right, and Rahul Shah left inside a target chamber where the TRIDENT short pulse laser is aimed at a very thin diamond- foil target, a fraction of a micrometer thick. The laser delivers a power on target of 150 Terawatts focused into a 7 micrometer spot, yielding laser brilliance over 100 times more intense than needed to make the target electrons fully relativistic. These experiments test novel methods of producing intense

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


361

Fabrication of low density ceramic material  

DOE Patents (OSTI)

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.

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

1985-01-01T23:59:59.000Z

362

Low density, microcellular foams, preparation, and articles  

DOE Patents (OSTI)

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.

Young, A.T.

1982-03-03T23:59:59.000Z

363

NEUTRON DENSITY CONTROL IN A NEUTRONIC REACTOR  

DOE Patents (OSTI)

The method and means for controlling the neutron density in a nuclear reactor is described. It describes the method and means for flattening the neutron density distribution curve across the reactor by spacing the absorbing control members to varying depths in the central region closer to the center than to the periphery of the active portion of the reactor to provide a smaller neutron reproduction ratio in the region wherein the members are inserted, than in the remainder of the reactor thereby increasing the over-all potential power output.

Young, G.J.

1959-06-30T23:59:59.000Z

364

Dark Energy Density in Brane World  

E-Print Network (OSTI)

We present a possible explanation to the tiny positive cosmological constant under the frame of AdS$_5$ spacetime embedded by a dS$_4$ brane. We calculate the dark energy density by summing the zero point energy of massive scalar fields in AdS$_5$ spacetime. Under the assumption that the radius of AdS$_5$ spacetime is of the same magnitude as the radius of observable universe, the dark energy density in dS$_4$ brane is obtained, which is smaller than the observational value. The reasons are also discussed.

Hai-Bao Wen; Xin-Bing Huang

2005-02-08T23:59:59.000Z

365

Relation between the High Density Phase and the Very-High Density Phase of Amorphous Solid Water  

E-Print Network (OSTI)

Relation between the High Density Phase and the Very-High Density Phase of Amorphous Solid Water; published 18 March 2005) It has been suggested that high-density amorphous (HDA) ice is a structurally arrested form of high- density liquid (HDL) water, while low-density amorphous ice is a structurally

Sciortino, Francesco

366

Density estimation for spatial data streams  

Science Conference Proceedings (OSTI)

In this paper we study the problem of estimating several types of spatial queries in a streaming environment. We propose a new approach, which we call Local Kernels, for computing density estimators by using local rather than global statistics on the ...

Cecilia M. Procopiuc; Octavian Procopiuc

2005-08-01T23:59:59.000Z

367

Lattice QCD and High Baryon Density State  

SciTech Connect

We report our recent studies on the finite density QCD obtained from lattice QCD simulation with clover-improved Wilson fermions of two flavor and RG-improved gauge action. We approach the subject from two paths, i.e., the imaginary and chemical potentials.

Nagata, Keitaro [Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan); Research Institute for Information Science and Education, Hiroshima University, Higashi-Hiroshima 739-8527 (Japan); Nakamura, Atsushi; Motoki, Shinji [Research Institute for Information Science and Education, Hiroshima University, Higashi-Hiroshima 739-8527 (Japan); Nakagawa, Yoshiyuki [Graduate School of Science and Technology, Niigata University, Niigata 950-2181 (Japan); Saito, Takuya [Integrated Information Center, Kochi University, Kochi, 780-8520 (Japan)

2011-10-21T23:59:59.000Z

368

Interferometer for the measurement of plasma density  

SciTech Connect

An interferometer which combines the advantages of a coupled cavity interferometer requiring alignment of only one light beam, and a quadrature interferometer which has the ability to track multi-fringe phase excursions unambiguously. The device utilizes a Bragg cell for generating a signal which is electronically analyzed to unambiguously determine phase modulation which is proportional to the path integral of the plasma density.

Jacobson, Abram R. (Los Alamos, NM)

1980-01-01T23:59:59.000Z

369

Bayesian Generalized Probability Calculus for Density Matrices  

E-Print Network (OSTI)

One of the main concepts in quantum physics is a density matrix, which is a symmetric positive definite matrix of trace one. Finite probability distributions can be seen as a special case when the density matrix is restricted to be diagonal. We develop a probability calculus based on these more general distributions that includes definitions of joints, conditionals and formulas that relate these, including analogs of the Theorem of Total Probability and various Bayes rules for the calculation of posterior density matrices. The resulting calculus parallels the familiar "conventional" probability calculus and always retains the latter as a special case when all matrices are diagonal. We motivate both the conventional and the generalized Bayes rule with a minimum relative entropy principle, where the Kullbach-Leibler version gives the conventional Bayes rule and Umegaki's quantum relative entropy the new Bayes rule for density matrices. Whereas the conventional Bayesian methods maintain uncertainty about which model has the highest data likelihood, the generalization maintains uncertainty about which unit direction has the largest variance. Surprisingly the bounds also generalize: as in the conventional setting we upper bound the negative log likelihood of the data by the negative log likelihood of the MAP estimator.

Manfred K Warmuth; Dima Kuzmin

2009-01-09T23:59:59.000Z

370

Nature of the beam-density effect on energy loss by nonrelativistic charged-particle beams  

DOE Green Energy (OSTI)

The authors present a new formulation of the beam-density effect on energy loss by charged particles passing through matter, which exhibits an increased loss with a beam-shape dependence. This arises from a long-range dipolelike term contained in the two-particle vicinage function for cooperative energy loss by a pair of nonrelativistic particles. A new analytic expression for the vicinage function, which exhibits the long-range term, is also presented.

Rule, D.W.; Crawford, O.H.

1984-03-12T23:59:59.000Z

371

PSOLV: a code for calculating the potentials and densities in MFTF-B  

SciTech Connect

Code PSOLV solves for potential and densities at the cardinal points of MFTF-B. The code is equipped to handle both the throttle-coil and the axicell geometries. For the throttle-coil case, the potential at point MXO is input, while the potentials and densities at points MAI, b, and A are calculated. For the axicell case, the code must additionally solve for the potentials and densities at points X and MXO. PSOLV is intended primarily for use as a subroutine in TREQ, a code being developed by Rensink that calculates the densities and potentials at the cardinal points of MFTF-B as a function of time. TREQ is to be used for modeling start-up behavior.

Colborn, J.A.

1983-08-17T23:59:59.000Z

372

On the alternatives for bath correlators and spectral densities from mixed quantum-classical simulations  

Science Conference Proceedings (OSTI)

We investigate on the procedure of extracting a 'spectral density' from mixed QM/MM calculations and employing it in open quantum systems models. In particular, we study the connection between the energy gap correlation function extracted from ground state QM/MM and the bath spectral density used as input in open quantum system approaches. We introduce a simple model which can give intuition on when the ground state QM/MM propagation will give the correct energy gap. We also discuss the role of higher order correlators of the energy-gap fluctuations which can provide useful information on the bath. Further, various semiclassical corrections to the spectral density, are applied and investigated. Finally, we apply our considerations to the photosynthetic Fenna-Matthews-Olson complex. For this system, our results suggest the use of the Harmonic prefactor for the spectral density rather than the Standard one, which was employed in the simulations of the system carried out to date.

Valleau, Stephanie; Aspuru-Guzik, Alan [Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138 (United States); Eisfeld, Alexander [Max Planck Institute for the Physics of Complex Systems, Noethnitzer Strasse 38, 01187 Dresden (Germany)

2012-12-14T23:59:59.000Z

373

Vibrated Bulk Density (VBD) of Calcined Petroleum Coke and ...  

Science Conference Proceedings (OSTI)

Abstract Scope, Vibrated bulk density (VBD) is a quantitative measurement used in the aluminum industry to evaluate the density of calcined petroleum coke.

374

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

National Nuclear Security Administration (NNSA)

NNSA Archive Federal Employment Apply for Our Jobs Our Jobs Working at NNSA Blog High Energy Density Laboratory Plasmas Program Home > High Energy Density Laboratory Plasmas...

375

An Optimization of Electrode Energy and Power Density through...  

NLE Websites -- All DOE Office Websites (Extended Search)

An Optimization of Electrode Energy and Power Density through of Variations in Inactive Material and Electrode Porosity Title An Optimization of Electrode Energy and Power Density...

376

THE COLUMN DENSITY VARIANCE IN TURBULENT INTERSTELLAR MEDIA: A FRACTAL MODEL APPROACH  

Science Conference Proceedings (OSTI)

Fractional Brownian motion structures are used to investigate the dependency of column density variance ({sigma}{sup 2}{sub lnN}) in the turbulent interstellar medium on the variance of three-dimensional density ({sigma}{sup 2}{sub ln{rho}}) and the power-law slope of the density power spectrum. We provide quantitative expressions to infer the three-dimensional density variance, which is not directly observable, from the observable column density variance and spectral slope. We also investigate the relationship between the column density variance and sonic Mach number (M{sub s}) in the hydrodynamic (HD) regime by assuming the spectral slope and density variance to be functions of sonic Mach number, as obtained from the HD turbulence simulations. They are related by the expression {sigma}{sup 2}{sub lnN} = A{sigma}{sub ln{rho}} {sup 2} = Aln (1 + b {sup 2} M{sup 2}{sub s}), suggested by Burkhart and Lazarian for the magnetohydrodynamic case. The proportional constant A varies from Almost-Equal-To 0.2 to Almost-Equal-To 0.4 in the HD regime as the turbulence forcing parameter b increases from 1/3 (purely solenoidal forcing) to 1 (purely compressive forcing). It is also discussed that the parameter A is lowered in the presence of a magnetic field.

Seon, Kwang-Il, E-mail: kiseon@kasi.re.kr [Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of); Astronomy and Space Science Major, University of Science and Technology, Daejeon 305-350 (Korea, Republic of)

2012-12-20T23:59:59.000Z

377

High Island Densities and Long Range Repulsive Interactions: Fe on Epitaxial Graphene  

SciTech Connect

The understanding of metal nucleation on graphene is essential for promising future applications, especially of magnetic metals which can be used in spintronics or computer storage media. A common method to study the grown morphology is to measure the nucleated island density n as a function of growth parameters. Surprisingly, the growth of Fe on graphene is found to be unusual because it does not follow classical nucleation: n is unexpectedtly high, it increases continuously with the deposited amount ? and shows no temperature dependence. These unusual results indicate the presence of long range repulsive interactions. Kinetic Monte Carlo simulations and density functional theory calculations support this conclusion. In addition to answering an outstanding question in epitaxial growth, i.e., to find systems where long range interactions are present, the high density of magnetic islands, tunable with ?, is of interest for nanomagnetism applications.

Binz, Steven M.; Hupalo, Myron; Liu, Xiaojie; Wang, Cai-Zhuang; Lu, Wen-Cai; Thiel, Kai-Ming; Conrad, E.H.; Tringides, Michael C.

2012-07-13T23:59:59.000Z

378

Droplet minimizers for the Cahn Hilliard free energy functional  

E-Print Network (OSTI)

We prove theorem characterizing the minimizers in a model for condensation based on the Cahn Hilliard free energy functional. In particular, we exactly determine the critical density for droplet formation.

E. A. Carlen; M. C. Carvalho; R. Esposito; J. L. Lebowitz; R. Marra

2005-05-11T23:59:59.000Z

379

Effective pairing interactions with isospin density dependence  

Science Conference Proceedings (OSTI)

We perform Hartree-Fock-Bogoliubov (HFB) calculations for semi-magic calcium, nickel, tin, and lead isotopes and N=20,28,50, and 82 isotones using density-dependent pairing interactions recently derived from a microscopic nucleon-nucleon interaction. These interactions have an isovector component so that the pairing gaps in symmetric and neutron matter are reproduced. Our calculations well account for the experimental data for the neutron number dependence of binding energy, two-neutron separation energy, and odd-even mass staggering of these isotopes. This result suggests that by introducing the isovector term in the pairing interaction, one can construct a global effective pairing interaction that is applicable to nuclei in a wide range of the nuclear chart. It is also shown with the local density approximation that the pairing field deduced from the pairing gaps in infinite matter reproduces qualitatively well the pairing field for finite nuclei obtained with the HFB method.

Margueron, J. [Institut de Physique Nucleaire, IN2P3-CNRS and Universite Paris-Sud, F-91406 Orsay Cedex (France); Center for Mathematical Sciences, University of Aizu, Aizu-Wakamatsu, 965-8580 Fukushima (Japan); Sagawa, H. [Center for Mathematical Sciences, University of Aizu, Aizu-Wakamatsu, 965-8580 Fukushima (Japan); Hagino, K. [Department of Physics, Tohoku University, Sendai, 980-8578 (Japan)

2008-05-15T23:59:59.000Z

380

Kinetics driving high-density chlorine plasmas  

Science Conference Proceedings (OSTI)

A simple fluid model was developed in order to investigate the driving kinetics of neutral and charged species in high-density chlorine plasmas. It was found that the dissociation degree of Cl{sub 2} molecules is directly linked to the power balance of the discharge which controls the electron density. The model was also used to identify those reactions that could be neglected in the particle balance of charged species and those that must be included. Our results further indicate that diffusion losses need to be considered up to a pressure that depends on magnetic-field intensity and reactor aspect ratio. Finally, it is shown that the dominant charged carriers are linked to the dissociation level of Cl{sub 2} molecules.

Stafford, L.; Margot, J.; Vidal, F.; Chaker, M.; Giroux, K.; Poirier, J.-S.; Quintal-Leonard, A.; Saussac, J. [Department de physique, Universite de Montreal, Montreal, Quebec (Canada); INRS-Energie, Materiaux et Telecommunications, Varennes, Quebec (Canada); Department de physique, Universite de Montreal, Montreal, Quebec (Canada)

2005-09-15T23:59:59.000Z

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


381

Turbulent Density Spectrum in Solar Wind Plasma  

E-Print Network (OSTI)

The density fluctuation spectrum in the solar wind reveals a Kolmogorov-like scaling with a spectral slope of -5/3 in wavenumber space. The energy transfer process in the magnetized solar wind, characterized typically by MHD turbulence, over extended length-scales remains an unresolved paradox of modern turbulence theories, raising the question of how a compressible magnetofluid exhibits a turbulent spectrum that is characteristic of an incompressible hydrodynamic fluid. To address these questions, we have undertaken three-dimensional time dependent numerical simulations of a compressible magnetohydrodynamic fluid describing super-Alfv\\'enic, supersonic and strongly magnetized plasma fluid. It is shown that a Kolmogorov-like density spectrum can develop by plasma motions that are dominated by Alfv\\'enic cascades whereas compressive modes are dissipated.

Shaikh, Dastgeer

2009-01-01T23:59:59.000Z

382

Density Spectrum in the Solar Wind Plasma  

E-Print Network (OSTI)

The density fluctuation spectrum in the solar wind reveals a Kolmogorov-like scaling with a spectral slope of -5/3 in wavenumber space. The energy transfer process in the magnetized solar wind, characterized typically by MHD turbulence, over extended length-scales remains an unresolved paradox of modern turbulence theories, raising the question of how a compressible magnetofluid exhibits a turbulent spectrum that is characteristic of an incompressible hydrodynamic fluid. To address these questions, we have undertaken three-dimensional time dependent numerical simulations of a compressible magnetohydrodynamic fluid describing super-Alfv\\'enic, supersonic and strongly magnetized plasma fluid. It is shown that a Kolmogorov-like density spectrum can develop by plasma motions that are dominated by Alfv\\'enic cascades whereas compressive modes are dissipated.

Shaikh, Dastgeer

2009-01-01T23:59:59.000Z

383

Density gradient free electron collisionally excited x-ray laser  

DOE Patents (OSTI)

An operational x-ray laser is provided that amplifies 3p-3s transition x-ray radiation along an approximately linear path. The x-ray laser is driven by a high power optical laser. The driving line focused optical laser beam illuminates a free-standing thin foil that may be associated with a substrate for improved structural integrity. This illumination produces a generally cylindrically shaped plasma having an essentially uniform electron density and temperature, that exists over a long period of time, and provides the x-ray laser gain medium. The x-ray laser may be driven by more than one optical laser beam. The x-ray laser has been successfully demonstrated to function in a series of experimental tests.

Campbell, E.M.; Rosen, M.D.

1984-11-29T23:59:59.000Z

384

Level densities of nickel isotopes: microscopic theory versus experiment  

E-Print Network (OSTI)

We apply a spin-projection method to calculate microscopically the level densities of a family of nickel isotopes $^{59-64}$Ni using the shell model Monte Carlo approach in the complete $pfg_{9/2}$ shell. Accurate ground-state energies of the odd-mass nickel isotopes, required for the determination of excitation energies, are determined using the Green's function method recently introduced to circumvent the odd particle-number sign problem. Our results are in excellent agreement with recent measurements based on proton evaporation spectra and with level counting data at low excitation energies. We also compare our results with neutron resonance data, assuming equilibration of parity and a spin-cutoff model for the spin distribution at the neutron binding energy, and find good agreement with the exception of $^{63}$Ni.

M. Bonett-Matiz; Abhishek Mukherjee; Y. Alhassid

2013-05-01T23:59:59.000Z

385

Velocity and density spectra of the Small Magellanic Cloud  

E-Print Network (OSTI)

This paper reports results on the statistical analysis of HI turbulence in the Small Magellanic Cloud (SMC). We use 21 cm channel maps, obtained with the Australia Telescope Compact Array and the Parkes telescope, and analyze the spectrum of observed intensity fluctuations as a function of the velocity slice thickness. We confirm predictions by Lazarian & Pogosyan (2000) on the change of the power law index and establish the spectra of 3-D density and velocity. The obtained spectral indices, -3.3 and -3.4, are slightly more shallow than the predictions for the Kolmogorov spectrum. This contrasts to the predictions for the shock-type spectra that are steeper than the Kolmogorov one. The nature of the energy injection in the SMC is unclear as no distinct energy injection scales are observed up to the entire scale of the SMC.

S. Stanimirovi?; A. Lazarian

2001-02-11T23:59:59.000Z

386

Mapping densities in a noisy state space  

E-Print Network (OSTI)

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.

Domenico Lippolis

2013-03-05T23:59:59.000Z

387

Lipoprotein subclass analysis by immunospecific density  

E-Print Network (OSTI)

Apolipoprotein C-1 (apo C-1) enriched HDL has been described as an atherogenic form of HDL associated with an increased risk for cardiovascular disease (CVD). The objective of the present study was to develop a rapid method for the separation, purification, and characterization of Apo C-1 from serum. We isolated and characterize HDL subclasses from individuals with and without angiographically-proven CVD who have elevated and normal-to-low HDL-C levels. Ultracentrifugation was linked with immunoaffinity separations for the specific separation of Apo C-1 enriched HDL from other lipoproteins. A 50 ?L sample of serum is diluted in TRIS HCl buffer (pH 7.5) and incubated with CNBr-activated Sepharose (Amersham) containing antibodies to apo C-1 (Academy Bio-medical Company). The apo C-1-depleted serum is removed by centrifugation and all apo C-1-containing lipoproteins are released from the Sepharose beads at pH 2. The apo C-1-depleted sample and the apo C-1-containing sample were ultracentrifuged 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 HDL. An additional advantage of this approach is that lipoprotein-a (Lp(a)), which is often an interfering component in the HDL density region, is eliminated. Results show feasibility that these methods could be used in a clinical setting, was achieved. This measurement may yield a precise and quantitative profile of the distribution of apo C-1 for all lipoprotein particles including HDL.

Lester, Sandy Marie

2008-12-01T23:59:59.000Z

388

Geometry dependent current-voltage characteristics of ZnO nanostructures: A combined nonequilibrium Green's function and density functional  

E-Print Network (OSTI)

Intramolecular excimer emission as a blue light source in fluorescent organic light emitting diodes Light Emitting Diode (OLED), intermolecular p­p interactions should be usually suppressed to avoid any Emitting Diodes (SMOLEDs) is almost absent from the literature. In this work, three aryl-substituted Di

Melnik, Roderick

389

Energy trapping from Hagedorn densities of states  

E-Print Network (OSTI)

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.

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

2013-04-26T23:59:59.000Z

390

ON THE LOCAL DARK MATTER DENSITY  

SciTech Connect

An analysis of the kinematics of 412 stars at 1-4 kpc from the Galactic midplane by Moni Bidin et al. has claimed to derive a local density of dark matter that is an order of magnitude below standard expectations. We show that this result is incorrect and that it arises from the assumption that the mean azimuthal velocity of the stellar tracers is independent of Galactocentric radius at all heights. We substitute the assumption, supported by data, that the circular speed is independent of radius in the midplane. We demonstrate that the assumption of constant mean azimuthal velocity is implausible by showing that it requires the circular velocity to drop more steeply than allowed by any plausible mass model, with or without dark matter, at large heights above the midplane. Using the approximation that the circular-velocity curve is flat in the midplane, we find that the data imply a local dark matter density of 0.008 {+-} 0.003 M{sub Sun} pc{sup -3} = 0.3 {+-} 0.1 GeV cm{sup -3}, fully consistent with standard estimates of this quantity. This is the most robust direct measurement of the local dark matter density to date.

Bovy, Jo; Tremaine, Scott [Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540 (United States)

2012-09-01T23:59:59.000Z

391

High Energy Density Utracapacitors: Low-Cost, High Energy and Power Density, Nanotube-Enhanced Ultracapacitors  

Science Conference Proceedings (OSTI)

Broad Funding Opportunity Announcement Project: FastCAP is improving the performance of an ultracapacitor—a battery-like electronic device that can complement, and possibly even replace, an HEV or EV battery pack. Ultracapacitors have many advantages over conventional batteries, including long lifespans (over 1 million cycles, as compared to 10,000 for conventional batteries) and better durability. Ultracapacitors also charge more quickly than conventional batteries, and they release energy more quickly. However, ultracapacitors have fallen short of batteries in one key metric: energy density—high energy density means more energy storage. FastCAP is redesigning the ultracapacitor’s internal structure to increase its energy density. Ultracapacitors traditionally use electrodes made of irregularly shaped, porous carbon. FastCAP’s ultracapacitors are made of tiny, aligned carbon nanotubes. The nanotubes provide a regular path for ions moving in and out of the ultracapacitor’s electrode, increasing the overall efficiency and energy density of the device.

None

2010-04-01T23:59:59.000Z

392

PROCESS FOR IMPROVING THE ENERGY DENSITY OF FEEDSTOCKS USING ...  

PROCESS FOR IMPROVING THE ENERGY DENSITY OF FEEDSTOCKS USING FORMATE SALTS United States Patent Application

393

On the density of a graph and its blowup  

Science Conference Proceedings (OSTI)

It is well known that, of all graphs with edge-density p, the random graph G(n,p) contains the smallest density of copies of K"t","t, the complete bipartite graph of size 2t. Since K"t","t is a t-blowup of an edge, the following intriguing open question ... Keywords: Blowup, Graph density, Triangle density

Asaf Shapira; Raphael Yuster

2010-11-01T23:59:59.000Z

394

Nanotechnology in Thoracic Surgery Morgan D. Schulz, MD, Onkar Khullar, MD, John V. Frangioni, MD, PhD,  

E-Print Network (OSTI)

of the lung and the preva- lence of occult micrometastatic disease within thoracic nodes which may appear be due to an increased detection of nodal disease or increased re- moval of nodes harboring occult foci

395

Obtaining the Probability Vector Current Density in Canonical Quantum Mechanics by Linear Superposition  

E-Print Network (OSTI)

The quantum mechanics status of the probability vector current density has long seemed to be marginal. On one hand no systematic prescription for its construction is provided, and the special examples of it that are obtained for particular types of Hamiltonian operator could conceivably be attributed to happenstance. On the other hand this concept's key physical interpretation as local average particle flux, which flows from the equation of continuity that it is supposed to satisfy in conjunction with the probability scalar density, has been claimed to breach the uncertainty principle. Given the dispiriting impact of that claim, we straightaway point out that the subtle directional nature of the uncertainty principle makes it consistent with the measurement of local average particle flux. We next focus on the fact that the unique closed-form linear-superposition quantization of any classical Hamiltonian function yields in tandem the corresponding unique linear-superposition closed-form divergence of the probability vector current density. Because the probability vector current density is linked to the quantum physics only through the occurrence of its divergence in the equation of continuity, it is theoretically most appropriate to construct this vector field exclusively from its divergence -- analysis of the best-known "textbook" special example of a probability vector current density shows that it is thus constructed. That special example in fact leads to the physically interesting "Ehrenfest subclass" of probability vector current densities, which are closely related to their classical peers.

Steven Kenneth Kauffmann

2013-02-02T23:59:59.000Z

396

Packing microstructure and local density variations of experimental and computational pebble beds  

Science Conference Proceedings (OSTI)

In pebble bed type nuclear reactors the fuel is contained in graphite pebbles, which form a randomly stacked bed with a non-uniform packing density. These variations can influence local coolant flow and power density and are a possible cause of hotspots. To analyse local density variations computational methods are needed that can generate randomly stacked pebble beds with a realistic packing structure on a pebble-to-pebble level. We first compare various properties of the local packing structure of a computed bed with those of an image made using computer aided X-ray tomography, looking at properties in the bulk of the bed and near the wall separately. Especially for the bulk of the bed, properties of the computed bed show good comparison with the scanned bed and with literature, giving confidence our method generates beds with realistic packing microstructure. Results also show the packing structure is different near the wall than in the bulk of the bed, with pebbles near the wall forming ordered layers similar to hexagonal close packing. Next, variations in the local packing density are investigated by comparing probability density functions of the packing fraction of small clusters of pebbles throughout the bed. Especially near the wall large variations in local packing fractions exists, with a higher probability for both clusters of pebbles with low (0.65) packing fraction, which could significantly affect flow rates and, together with higher power densities, could result in hotspots. (authors)

Auwerda, G. J.; Kloosterman, J. L.; Lathouwers, D.; Van Der Hagen, T. H. J. J. [Delft Univ. of Technology, Mekelweg 15, 2629 JB, Delft (Netherlands)

2012-07-01T23:59:59.000Z

397

Functional Integration on Constrained Function Spaces  

E-Print Network (OSTI)

Analogy with Bayesian inference is used to study constrained physical systems within the context of functional integration. Since functional integrals probe function spaces, both kinematical and dynamical constraints are treated simultaneously and on equal footing. Following the analogy, functional counterparts of conditional and conjugate probability distributions are introduced for integrators and then applied to some well-known examples of constrained functional integrals. The analysis leads to some new functional integration tools and methods. These are utilized to construct a model of the prime counting function as a constrained gamma process.

J. LaChapelle

2012-12-03T23:59:59.000Z

398

Free energy density for mean field perturbation of states of a one-dimensional spin chain  

E-Print Network (OSTI)

Motivated by recent developments on large deviations in states of the spin chain, we reconsider the work of Petz, Raggio and Verbeure in 1989 on the variational expression of free energy density in the presence of a mean field type perturbation. We extend their results from the product state case to the Gibbs state case in the setting of translation-invariant interactions of finite range. In the special case of a locally faithful quantum Markov state, we clarify the relation between two different kinds of free energy densities (or pressure functions).

Fumio Hiai; Milan Mosonyi; Hiromichi Ohno; Denes Petz

2007-06-28T23:59:59.000Z

399

Local Hotels/Motels - Gaithersburg, MD  

Science Conference Proceedings (OSTI)

... relationship with NIST. We provide this information as a convenience to NIST visitors and conference attendees. NIST does ...

2013-07-25T23:59:59.000Z

400

Fissile Material Disposition (MD) - Nuclear Engineering Division...  

NLE Websites -- All DOE Office Websites (Extended Search)

a legacy of surplus fissile materials (primarily weapons-grade plutonium and highly enriched uranium) in the United States and the former Soviet Union. These materials pose a...

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


401

Community Academic Profile Jon D. Fuller, MD  

E-Print Network (OSTI)

, Gerontology, & Metabolism ACTIVITIES 2006 Member, VHA Capacity Management Advisory Council, VA HQ. 2005 Member, VHA Clinical Advisory Council to Chief Business Office, VA HQ. 2005 VA representative to the White Forum Steering Committee Member, "Standardizing Home Health Care Performance Measures" 2004 Organizer

Ford, James

402

Student Directory yea Larry S. Tobacman, MD  

E-Print Network (OSTI)

Genetics St Louis, 2007 Andrew Czysz (2007) aczysz2@uic.edu th Year PhD logy, U. Florida, 2007 Durst (2012

Alford, Simon

403

Vehicle Technologies Office: Fact #661: February 7, 2011 Population Density  

NLE Websites -- All DOE Office Websites (Extended Search)

1: February 7, 1: February 7, 2011 Population Density to someone by E-mail Share Vehicle Technologies Office: Fact #661: February 7, 2011 Population Density on Facebook Tweet about Vehicle Technologies Office: Fact #661: February 7, 2011 Population Density on Twitter Bookmark Vehicle Technologies Office: Fact #661: February 7, 2011 Population Density on Google Bookmark Vehicle Technologies Office: Fact #661: February 7, 2011 Population Density on Delicious Rank Vehicle Technologies Office: Fact #661: February 7, 2011 Population Density on Digg Find More places to share Vehicle Technologies Office: Fact #661: February 7, 2011 Population Density on AddThis.com... Fact #661: February 7, 2011 Population Density The density of the population in the U.S., measured as the number of people

404

Metrology Challenges for High Energy Density Science Target Manufacture  

Science Conference Proceedings (OSTI)

Currently, High Energy Density Science (HEDS) experiments are used to support and qualify predictive physics models. These models assume ideal conditions such as energy (input) and device (target) geometry. The experiments rely on precision targets constructed from components with dimensions in the millimeter range, while having micrometer-scale, functional features, including planar steps, sine waves, and step-joint geometry on hemispherical targets. Future target designs will likely have features and forms that rival or surpass current manufacturing and characterization capability. The dimensional metrology of these features is important for a number of reasons, including qualification of sub-components prior to assembly, quantification of critical features on the as-built assemblies and as a feedback mechanism for fabrication process development. Variations in geometry from part to part can lead to functional limitations, such as unpredictable instabilities during an experiment and the inability to assemble a target from poorly matched sub-components. Adding to the complexity are the large number and variety of materials, components, and shapes that render any single metrology technique difficult to use with low uncertainty. Common materials include metal and glass foams, doped transparent and opaque plastics and a variety of deposited and wrought metals. A suite of metrology tools and techniques developed to address the many critical issues relevant to the manufacture of HEDS targets including interferometry, x-ray radiography and contact metrology are presented including two sided interferometry for absolute thickness metrology and low force probe technology for micrometer feature coordinate metrology.

Seugling, R M; Bono, M J; Davis, P

2009-02-19T23:59:59.000Z

405

Excited states and electron transfer in solution : models based on density functional theory  

E-Print Network (OSTI)

Our understanding of organic materials for solar energy conversion stands to benefit greatly from accurate, computationally tractable electronic structure methods for excited states. Here we apply two approaches based on ...

Kowalczyk, Timothy Daniel

2012-01-01T23:59:59.000Z

406

Optical Properties of Cd1-xZnxSe from Density Functional Theory  

Science Conference Proceedings (OSTI)

For the purpose of exchange-correlation energy (Exc) determination in ... by Combining Thermoelectric Materials and Dye-Sensitized Solar Cell in Series.

407

Electrochemical Windows of Room-Temperature Ionic Liquids from Molecular Dynamics and Density Functional Theory Calculations  

E-Print Network (OSTI)

We investigated the cathodic and anodic limits of six room-temperature ionic liquids (ILs) formed from a combination of two common cations, 1-butyl-3-methylimidazolium (BMIM) and N,N-propylmethylpyrrolidinium (P13), and ...

Ong, Shyue Ping

408

Structure, magnetism, and adhesion at Cr/Fe interfaces from density functional theory  

E-Print Network (OSTI)

of industry due to its high melting point and wear resistance. For example, steel gun barrels are sub- jected has been aimed primarily at ceramic coatings/ liners (see, e.g. [4] and references therein). Ceramic­silicide ceramic/ iron interfaces (e.g., ZrC [7], TiC [8­10], and MoSi2 [11] on Fe substrates). While ceramics

Carter, Emily A.

409

van der Waals Corrected Density Functional Theory Calculations on Zeolitic Imidazolate Frameworks  

E-Print Network (OSTI)

separation of methane and carbon dioxide. J. Mater. Chem. ,Synthesis, structure, and carbon dioxide capture propertiesstructure, and carbon dioxide cap- ture properties of

Ray, Keith G.

2013-01-01T23:59:59.000Z

410

van der Waals Corrected Density Functional Theory Calculations on Zeolitic Imidazolate Frameworks  

E-Print Network (OSTI)

binding site and gas molecule, dispersion or a combinationsimple dispersion bound systems, such as noble gas dimersgas uptake differently due to the competition between surface area and strong dispersion

Ray, Keith G.

2013-01-01T23:59:59.000Z

411

Linear and Nonlinear Signatures in the Planetary Wave Dynamics of an AGCM: Probability Density Functions  

Science Conference Proceedings (OSTI)

To identify and quantify indications of linear and nonlinear planetary wave behavior and their impact on the distribution of atmospheric states, characteristics of a very long integration of an atmospheric general circulation model (GCM) in a ...

Judith Berner; Grant Branstator

2007-01-01T23:59:59.000Z

412

Efficiency and Power as a Function of Sequence Coverage, SNP Array Density, and Imputation  

E-Print Network (OSTI)

High coverage whole genome sequencing provides near complete information about genetic variation. However, other technologies can be more efficient in some settings by (a) reducing redundant coverage within samples and (b) ...

Flannick, Jason

413

Adsorption of binary hydrocarbon mixtures in carbon slit pores: A density functional theory study  

SciTech Connect

Adsorption of binary hydrocarbons mixtures involving methane in carbon slit pores is theoretically studied here from the viewpoints of separation and of the effect of impurities on methane storage. It is seen that even small amounts of ethane, propane, or butane can significantly reduce the methane capacity of carbons. Optimal pore sizes and pressures, depending on impurity concentration, are noted in the present work, suggesting that careful adsorbent and process design can lead to enhanced separation. These results are consistent with earlier literature studies for the infinite dilution limit. For methane storage applications a carbon micropore width of 11.4 {angstrom} (based on distance between centers of carbon atoms on opposing walls) is found to be the most suitable from the point of view of lower impurity uptake during high-pressure adsorption and greater impurity retention during low-pressure delivery. The results also theoretically confirm unusual recently reported observations of enhanced methane adsorption in the presence of a small amount of heavier hydrocarbon impurity.

Bhatia, S.K. [Univ. of Queensland, Brisbane, Queensland (Australia). Dept. of Chemical Engineering

1998-10-13T23:59:59.000Z

414

Density Functional Theory Calculations on Hydrated Dimethylarsinic Acid and Iron Oxide Clusters.  

E-Print Network (OSTI)

??Dimethylarsinic Acid (DMA) or (CH3)2AsO2H is an important organoarsenical compound detected in arsenic speciation studies of environmental samples and synthesized during pyrolysis of oil shale.… (more)

Adamescu, Adrian

2012-01-01T23:59:59.000Z

415

Electronic structure effects in liquid water studied by photoelectron spectroscopy and density functional theory  

E-Print Network (OSTI)

in comparison with gas-phase water, ice close to the meltingcrystalline ice at two different temperatures, and gas-phaseof gas-phase water, liquid water and crystalline ice using

Nordlund, Dennis

2008-01-01T23:59:59.000Z

416

First-principles Study Using Hybrid-density Functional Theory for the ...  

Science Conference Proceedings (OSTI)

Alloy compositions for active optical transitions and the formation energy are compared ... Advanced Materials and Processes for Solid Oxide Fuel Cells.

417

Electronic structure effects in liquid water studied by photoelectron spectroscopy and density functional theory  

E-Print Network (OSTI)

Radiation Laboratory (SSRL). The UHV surface scienceSciences. The work at the SSRL BL 5.1 and ALS BL 11.0.2 wasto thank the staff at SSRL and ALS for all their assistance.

Nordlund, Dennis

2008-01-01T23:59:59.000Z

418

Spontaneous fission modes and lifetimes of super-heavy elements in the nuclear density functional theory  

E-Print Network (OSTI)

Lifetimes of super-heavy (SH) nuclei are primarily governed by alpha decay and spontaneous fission (SF). Here we study the competing decay modes of even-even SH isotopes with 108 cold fusion" and "hot fusion" reactions. The region of long-lived SH nuclei is expected to be centered on $^{294}$Ds with a total half-life of ?1.5 days.

A. Staszczak; A. Baran; W. Nazarewicz

2012-08-06T23:59:59.000Z

419

Non-delta-function electronic spectral densities in individual quantum dots  

Science Conference Proceedings (OSTI)

Using a simplified model approach we estimate the optical line shape of the transition lines observable in photoluminescence experiments on quantum dots. We use the theory based on the interaction of electrons with the longitudinal optical phonons only. ... Keywords: 73.21.La, 73.63.Kv, 78.67.Hc, Electron-phonon coupling, Luminescence, Quantum dots

Karel Král

2008-03-01T23:59:59.000Z

420

''Inelastic Neutron Scattering and Periodic Density Functional Studies of Hydrogen Bonded Structures''  

DOE Green Energy (OSTI)

This project is directed at a fundamental understanding of hydrogen bonding, the primary reversible interaction leading to defined geometries, networks and supramolecular aggregates formed by organic molecules. Hydrogen bonding is still not sufficiently well understood that the geometry of such supramolecular aggregates can be predicted. In the approach taken existing quantum chemical methods capable of treating periodic solids have been applied to hydrogen bonded systems of known structure. The equilibrium geometry for the given space group and packing arrangement were computed and compared to that observed. The second derivatives and normal modes of vibration will then be computed and from this inelastic neutron scattering (INS) spectra were computed using the normal mode eigenvectors to compute spectral intensities. Appropriate inclusion of spectrometer line width and shape was made in the simulation and overtones, combinations and phonon wings were be included. These computed spectra were then compared with experimental results obtained for low-temperature polycrystalline samples at INS spectrometers at several facilities. This procedure validates the computational methodology for describing these systems including both static and dynamic aspects of the material. The resulting description can be used to evaluate the relative free energies of two or more proposed structures and so ultimately to be able to predict which structure will be most stable for a given building block.

Bruce S. Hudson

2004-10-27T23:59:59.000Z

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


421

P1-09: Atomic Density Function 3D Modeling of Crystal Growth with ...  

Science Conference Proceedings (OSTI)

P1-04: 3D Microstructural Characterization of Uranium Oxide as a Surrogate Nuclear ... P1-15: Gating System Optimisation Design Study of a Cast Automobile ... P2-27: Characterization of Carbonate Rocks through X-ray Microtomography.

422

Electronic structure effects in liquid water studied by photoelectron spectroscopy and density functional theory  

DOE Green Energy (OSTI)

We present valence photoelectron emission spectra of liquid water in comparison with gas-phase water, ice close to the melting point, low temperature amorphous and crystalline ice. All aggregation states have major electronic structure changes relative to the free molecule, with rehybridization and development of bonding and anti-bonding states accompanying the hydrogen bond formation. Sensitivity to the local structural order, most prominent in the shape and splitting of the occupied 3a{sub 1} orbital, is understood from the electronic structure averaging over various geometrical structures, and reflects the local nature of the orbital interaction.

Nordlund, Dennis; Odelius, Michael; Bluhm, Hendrik; Ogasawara, Hirohito; Pettersson, Lars G.M.; Nilsson, Anders

2008-04-29T23:59:59.000Z

423

First-principles Study Using Hybrid-density Functional Theory for the ...  

Science Conference Proceedings (OSTI)

A21: First-Principles Molecular Dynamics Simulation of Chemical ... A3: Investigation on Co-combustion Kinetics of Anthracite Coal and Biomass Char by ... Lithium Redox Process for Thermochemical Water-Splitting as Energy Conversion.

424

Irradiation-Induced Magnetism in Graphite: A Density Functional Study P. O. Lehtinen,1  

E-Print Network (OSTI)

either passivated with hydro- gen atoms [8,9,14] or free [6,9]. Structural defects, in general, give rise irradiation dose, particle energy, and irradiation temperature. Thus, if irradiation of the originally. A kinetic energy cutoff of 400 eV was found to converge the total energy of our systems to within meV. All

Krasheninnikov, Arkady V.

425

Density functional study of carbonic acid clusters P. Ballone,a)  

E-Print Network (OSTI)

atoms are gray, oxygen atoms black, hydro- gen atoms white. FIG. 3. Cohesive energy of linear clusters as the energy required to bend and stretch the linear isomers. Linear chains of up to 20 units should be favored ( -H2CO3) could be identified. The small energy differences involved in the formation of carbonic acid

426

The wind power probability density forecast problem can be formulated as: forecast the wind power pdf at time step t for each look-ahead time step t+k of a given time-horizon  

E-Print Network (OSTI)

The wind power probability density forecast problem can be formulated as: forecast the wind power forecasted for look-ahead time t+k, xt is a set of explanatory variables available at time step t, fP,x is the joint density function of the forecasted wind power and explanatory variables, fX is the density

Kemner, Ken

427

Ohmically heated high-density Z pinch  

SciTech Connect

The gross properties of a high-density (n approximately equal to 10$sup 27$ m$sup -3$), small-radius, (r = 10$sup -4$ m) gas-imbedded Z pinch have been examined considering only classical processes. The rate equation using only ohmic heating along with bremsstrahlung and radial heat transport shows that ohmic heating will rapidly take the pinch to thermonuclear temperatures for currents, I, greater than 1 MA. The radial heat loss for the pinch is very small for I greater than 1.5 MA. This suggests that the pinch could tolerate being driven to a nearby wall by an m = 1 kink. The laser technology for initiation of the small-diameter filament and the high-voltage technology for giving a 30-ns rise to a MA or more are available now. Some reactor considerations have been included. (auth)

Hammel, J.E.

1976-01-01T23:59:59.000Z

428

Competition between superconductivity and spin density wave  

E-Print Network (OSTI)

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.

Tian De Cao

2011-01-02T23:59:59.000Z

429

Vacuum Outgassing of High Density Polyethylene  

Science Conference Proceedings (OSTI)

A combination of thermogravimetric analysis (TGA) and temperature programmed decomposition (TPD) was employed to identify the outgassing species, the total amount of outgassing, and the outgassing kinetics of high density polyethylene (HDPE) in a vacuum environment. The isoconversional kinetic analysis was then used to analyze the outgassing kinetics and to predict the long-term outgassing of HDPE in vacuum applications at ambient temperature. H{sub 2}O and C{sub n}H{sub x} with n as high as 9 and x centering around 2n are the major outgassing species from solid HDPE, but the quantities evolved can be significantly reduced by vacuum baking at 368 K for a few hours prior to device assembly.

Dinh, L N; Sze, J; Schildbach, M A; Chinn, S C; Maxwell, R S; Raboin, P; McLean II, W

2008-08-11T23:59:59.000Z

430

BRST technique for the cosmological density matrix  

E-Print Network (OSTI)

The microcanonical density matrix in closed cosmology has a natural definition as a projector on the space of solutions of Wheeler-DeWitt equations, which is motivated by the absence of global non-vanishing charges and energy in spatially closed gravitational systems. Using the BRST/BFV formalism in relativistic phase space of gauge and ghost variables we derive the path integral representation for this projector and the relevant statistical sum. This derivation circumvents the difficulties associated with the open algebra of noncommutative quantum Dirac constraints and the construction/regularization of the physical inner product in the subspace of BRS singlets. This inner product is achieved via the Batalin-Marnelius gauge fixing in the space of BRS-invariant states, which in its turn is shown to be a result of truncation of the BRST/BFV formalism to the "matter" sector of relativistic phase space.

Andrei O. Barvinsky

2013-08-14T23:59:59.000Z

431

High power density supercapacitors using locally aligned carbon nanotube electrodes  

E-Print Network (OSTI)

B E 1999 Electrochemical Supercapacitor ( New York: Kluwer–power density of a supercapacitor is its most remarkablepower density of a supercapacitor is given by P max = V i

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

2005-01-01T23:59:59.000Z

432

Innovative fuel designs for high power density pressurized water reactor  

E-Print Network (OSTI)

One of the ways to lower the cost of nuclear energy is to increase the power density of the reactor core. Features of fuel design that enhance the potential for high power density are derived based on characteristics of ...

Feng, Dandong, Ph. D. Massachusetts Institute of Technology

2006-01-01T23:59:59.000Z

433

Design of annular fuel for high power density BWRs  

E-Print Network (OSTI)

Enabling high power density in the core of Boiling Water Reactors (BWRs) is economically profitable for existing or new reactors. In this work, we examine the potential for increasing the power density in BWR plants by ...

Morra, Paolo

2005-01-01T23:59:59.000Z

434

Density of Freshly Fallen Snow in the Central Rocky Mountains  

Science Conference Proceedings (OSTI)

New snow density distributions are presented for six measurement sites in the mountains of Colorado and Wyoming. Densities were computed from daily measurements of new snow depth and water equivalent from snow board cores. All data were measured ...

Arthur Judson; Nolan Doesken

2000-07-01T23:59:59.000Z

435

Controlling Defect Density in Polymer-Fullerene Bulk Heterojunction ...  

Science Conference Proceedings (OSTI)

Controlling Defect Density in Polymer-Fullerene Bulk Heterojunction Solar Cells by Optimizing ... Engineering Carbon Nanomaterials for Energy Application.

436

Density without Disruption [EDRA / Places Awards, 2004 -- Awards Commentary  

E-Print Network (OSTI)

Density without Disruption Awards Commentary country today,CCS Architecture for a planning award. Such work stands as a

Gratz, Roberta Brandes

2004-01-01T23:59:59.000Z

437

Inexpensive Production of High Density Thin Ceramic Films ...  

For Industry; For Researchers; Success Stories; About Us; Available Technologies. Browse By Category Advanced Materials; ... density of the ceramic ...

438

Fatigue Weak-Link Density and Strength Distribution in High ...  

Science Conference Proceedings (OSTI)

Symposium, Fatigue and Corrosion Damage in Metallic Materials: Fundamentals, Modeling and Prevention. Presentation Title, Fatigue Weak-Link Density and ...

439

Improving Baked Anode Density and Air Permeability Through ...  

Science Conference Proceedings (OSTI)

Presentation Title, Improving Baked Anode Density and Air Permeability Through Process Optimization and Coke Blending. Author(s), Bienvenu Ndjom, ...

440

A digital rock density map of New Zealand  

Science Conference Proceedings (OSTI)

Digital geological maps of New Zealand (QMAP) are combined with 9256 samples with rock density measurements from the national rock catalogue PETLAB and supplementary geological sources to generate a first digital density model of New Zealand. This digital ... Keywords: Crust, Database, Density, Geological mapping, Gravimetry, Rock types

Robert Tenzer; Pascal Sirguey; Mark Rattenbury; Julia Nicolson

2011-08-01T23:59:59.000Z

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


441

High fidelity field simulations using density and pressure based approaches  

Science Conference Proceedings (OSTI)

Density-based and pressure-based approaches in solving the Navier-Stokes equations for computational field simulations for compressible and incompressible flows have been presented. For the density-based flow solver, a generalized grid based framework ... Keywords: CFD, Density-based method, Pressure-based method

Gary C. Cheng; Roy P. Koomullil; Bharat K. Soni

2005-11-01T23:59:59.000Z

442

Density-Enthalpy Phase Diagram 0D Boiler Simulation  

E-Print Network (OSTI)

Density-Enthalpy Phase Diagram 0D Boiler Simulation Finite Element Method Further Research Finite Transitions #12;Density-Enthalpy Phase Diagram 0D Boiler Simulation Finite Element Method Further Research;Density-Enthalpy Phase Diagram 0D Boiler Simulation Finite Element Method Further Research Goal

Vuik, Kees

443

Quantum coherent switch utilizing commensurate nanoelectrode and charge density periodicities  

DOE Patents (OSTI)

A quantum coherent switch having a substrate formed from a density wave (DW) material capable of having a periodic electron density modulation or spin density modulation, a dielectric layer formed onto a surface of the substrate that is orthogonal to an intrinsic wave vector of the DW material; and structure for applying an external spatially periodic electrostatic potential over the dielectric layer.

Harrison, Neil (Santa Fe, NM); Singleton, John (Los Alamos, NM); Migliori, Albert (Santa Fe, NM)

2008-08-05T23:59:59.000Z

444

Thermophysical Properties of Lithium Bromide + 1, 2-Propanediol Aqueous Solutions Solubility, Density and Viscosity  

SciTech Connect

The solubilities, densities and viscosities of lithium bromide (LiBr) + 1, 2-propanediol (HO-CH2-CHOH-CH3) aqueous solution (mass ratio of LiBr/HO-CH2-CHOH-CH3 = 3.5, 4.5 and 5.5) were measured in the mass fraction range from 0.30 to 0.75. Solubility measurements were performed by the visual method in the temperature range of (271.15 to 345.15) K. The density measurements were made using an automated vibrating tube density meter, and the viscosity measurements were carried out with an automated falling-ball viscometer in the temperature range of (293.15 to 363.15) K. The density and viscosity data were correlated with appropriate regression equations as a function of the mass fraction and temperature. The maximum average absolute deviations (AAD) between experimental and correlated data were 0.08% and 1.51% for densities and viscosities, respectively.

Wang, Kai [ORNL; Abdelaziz, Omar [ORNL; Vineyard, Edward Allan [ORNL

2012-01-01T23:59:59.000Z

445

Heavy quark free energies and screening at finite temperature and density  

E-Print Network (OSTI)

We study the free energies of heavy quarks calculated from Polyakov loop correlation functions in full 2-flavour QCD using the p4-improved staggered fermion action. A small but finite Baryon number density is included via Taylor expansion of the fermion determinant in the Baryo-chemical potential mu. For temperatures above Tc we extract Debye screening masses from the large distance behaviour of the free energies and compare their mu-dependence to perturbative results.

M. Doring; S. Ejiri; O. Kaczmarek; F. Karsch; E. Laermann

2005-09-27T23:59:59.000Z

446

wind power density | OpenEI  

Open Energy Info (EERE)

density density Dataset Summary Description This dataset was developed by the National Renewable Energy Laboratory (NREL) for the U.S. Source National Renewable Energy Lab (NREL) Date Released Unknown Date Updated Unknown Keywords afghanistan dataset GIS Wind Power wind power density Data application/zip icon Wind Power Density at 50-m Above Ground Level GIS Data (zip, 1.4 MiB) Quality Metrics Level of Review Some Review Comment Temporal and Spatial Coverage Frequency Time Period License License Other or unspecified, see optional comment below Comment DISCLAIMER NOTICE This GIS data was developed by the National Renewable Energy Laboratory ("NREL"), which is operated by the Alliance for Sustainable Energy, LLC for the U.S. Department of Energy ("DOE"). The user is granted the right, without any fee or cost, to use, copy, modify, alter, enhance and distribute this data for any purpose whatsoever, provided that this entire notice appears in all copies of the data. Further, the user of this data agrees to credit NREL in any publications or software that incorporate or use the data. Access to and use of the GIS data shall further impose the following obligations on the User. The names DOE/NREL may not be used in any advertising or publicity to endorse or promote any product or commercial entity using or incorporating the GIS data unless specific written authorization is obtained from DOE/NREL. The User also understands that DOE/NREL shall not be obligated to provide updates, support, consulting, training or assistance of any kind whatsoever with regard to the use of the GIS data. THE GIS DATA IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL DOE/NREL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER, INCLUDING BUT NOT LIMITED TO CLAIMS ASSOCIATED WITH THE LOSS OF DATA OR PROFITS, WHICH MAY RESULT FROM AN ACTION IN CONTRACT, NEGLIGENCE OR OTHER TORTIOUS CLAIM THAT ARISES OUT OF OR IN CONNECTION WITH THE ACCESS OR USE OF THE GIS DATA. The User acknowledges that access to the GIS data is subject to U.S. Export laws and regulations and any use or transfer of the GIS data must be authorized under those regulations. The User shall not use, distribute, transfer, or transmit GIS data or any products incorporating the GIS data except in compliance with U.S. export regulations. If requested by DOE/NREL, the User agrees to sign written assurances and other export-related documentation as may be required to comply with U.S. export regulations. DISCLAIMER NOTICE This GIS data was developed by the National Renewable Energy Laboratory ("NREL"), which is operated by the Alliance for Sustainable Energy, LLC for the U.S. Department of Energy ("DOE"). The user is granted the right, without any fee or cost, to use, copy, modify, alter, enhance and distribute this data for any purpose whatsoever, provided that this entire notice appears in all copies of the data. Further, the user of this data agrees to credit NREL in any publications or software that incorporate or use the data. Access to and use of the GIS data shall further impose the following obligations on the User. The names DOE/NREL may not be used in any advertising or publicity to endorse or promote any product or commercial entity using or incorporating the GIS data unless specific written authorization is obtained from DOE/NREL. The User also understands that DOE/NREL shall not be obligated to provide updates, support, consulting, training or assistance of any kind whatsoever with regard to the use of the GIS data. THE GIS DATA IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL DOE/NREL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER, INCLUDING BUT NOT LIMITED TO CLAIMS ASSOCIATED WITH THE LOSS OF DATA OR PROFITS, WHICH MAY RESULT FROM AN ACTION IN CONTRACT, NEGLIGENCE OR OTHER TORTIOUS CLAIM THAT ARISES OUT OF OR IN CONNECTION WITH THE ACCESS OR USE OF THE GIS DATA. The User acknowledges that access to the GIS data is subject to U.S. Export laws and regulations and any use or transfer of the GIS data must be authorized under those regulations. The User shall not use, distribute, transfer, or transmit GIS data or any products incorporating the GIS data except in compliance with U.S. export regulations. If requested by DOE/NREL, the User agrees to sign written assurances and other export-related documentation as may be required to comply with U.S. export regulations.

447

Functionalized Graphene Nanoroads for Quantum Well Device  

Science Conference Proceedings (OSTI)

Using density functional theory, a series of calculations of structural and electronic properties of Si-substituted graphene were conducted. Through substituting C atoms by Si atoms on graphene in the present study, we found that the band gap of graphene can be continuously tuned with differently substitutional concentration. To utilize such substitution-induced band gap changes, we proposed a special design to fabricate graphene-based quantum well device.

Zhou, Yungang; Yang, Ping; Wang, Zhiguo; Xiao, Hai Yan; Zu, Xiaotao T.; Sun, Xin; Khaleel, Mohammad A.; Gao, Fei

2011-03-02T23:59:59.000Z

448

Functional Mellin Transforms  

E-Print Network (OSTI)

Functional integrals are defined in terms of locally compact topological groups and their associated Banach-valued Haar integrals. This approach generalizes the functional integral scheme of Cartier and DeWitt-Morette. The definition allows a construction of functional Mellin transforms. In turn, the functional Mellin transforms can be used to define functional traces, logarithms, and determinants. The associated functional integrals are useful tools for probing function spaces in general and $C^\\ast$-algebras in particular. Several interesting aspects are explored. As an application, we construct a functional Mellin representation of the quantum evolution operator.

J. LaChapelle

2013-08-05T23:59:59.000Z

449

Functional Foods Package  

Science Conference Proceedings (OSTI)

Contains five (5) titles regarding functional foods. Functional Foods Package Health - Nutrition - Biochemistry Value Packages Nutrition Health Food Science Biochemistry This Value Package includes: ...

450

Flat Central Density Profile and Constant DM Surface Density in Galaxies from Scalar Field Dark Matter  

E-Print Network (OSTI)

The scalar field dark matter (SFDM) model proposes that galaxies form by condensation of a scalar field (SF) very early in the universe forming Bose-Einstein Condensates (BEC) drops, i.e., in this model haloes of galaxies are gigantic drops of SF. Here big structures form like in the LCDM model, by hierarchy, thus all the predictions of the LCDM model at big scales are reproduced by SFDM. This model predicts that all galaxies must be very similar and exist for bigger redshifts than in the LCDM model. In this work we show that BEC dark matter haloes fit high-resolution rotation curves of a sample of thirteen low surface brightness galaxies. We compare our fits to those obtained using a Navarro-Frenk-White and Pseudo-Isothermal (PI) profiles and found a better agreement with the SFDM and PI profiles. The mean value of the logarithmic inner density slopes is -0.27 +/- 0.18. As a second result we find a natural way to define the core radius with the advantage of being model-independent. Using this new definition in the BEC density profile we find that the recent observation of the constant dark matter central surface density can be reproduced. We conclude that in light of the difficulties that the standard model is currently facing the SFDM model can be a worthy alternative to keep exploring further.

Victor H. Robles; Tonatiuh Matos

2012-01-14T23:59:59.000Z

451

A H-infinity Fault Detection and Diagnosis Scheme for Discrete Nonlinear System Using Output Probability Density Estimation  

Science Conference Proceedings (OSTI)

In this paper, a H-infinity fault detection and diagnosis (FDD) scheme for a class of discrete nonlinear system fault using output probability density estimation is presented. Unlike classical FDD problems, the measured output of the system is viewed as a stochastic process and its square root probability density function (PDF) is modeled with B-spline functions, which leads to a deterministic space-time dynamic model including nonlinearities, uncertainties. A weighting mean value is given as an integral function of the square root PDF along space direction, which leads a function only about time and can be used to construct residual signal. Thus, the classical nonlinear filter approach can be used to detect and diagnose the fault in system. A feasible detection criterion is obtained at first, and a new H-infinity adaptive fault diagnosis algorithm is further investigated to estimate the fault. Simulation example is given to demonstrate the effectiveness of the proposed approaches.

Zhang Yumin; Lum, Kai-Yew [Temasek Laboratories, National University of Singapore, Singapore 117508 (Singapore); Wang Qingguo [Depa. Electrical and Computer Engineering, National University of Singapore, Singapore 117576 (Singapore)

2009-03-05T23:59:59.000Z

452

Thermodynamics and Structural Properties of the High Density Gaussian Core Model  

E-Print Network (OSTI)

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

Atsushi Ikeda; Kunimasa Miyazaki

2011-04-18T23:59:59.000Z

453

A Statistical Method for Estimating Luminosity Functions using Truncated Data  

E-Print Network (OSTI)

The observational limitations of astronomical surveys lead to significant statistical inference challenges. One such challenge is the estimation of luminosity functions given redshift $z$ and absolute magnitude $M$ measurements from an irregularly truncated sample of objects. This is a bivariate density estimation problem; we develop here a statistically rigorous method which (1) does not assume a strict parametric form for the bivariate density; (2) does not assume independence between redshift and absolute magnitude (and hence allows evolution of the luminosity function with redshift); (3) does not require dividing the data into arbitrary bins; and (4) naturally incorporates a varying selection function. We accomplish this by decomposing the bivariate density into nonparametric and parametric portions. There is a simple way of estimating the integrated mean squared error of the estimator; smoothing parameters are selected to minimize this quantity. Results are presented from the analysis of a sample of quasars.

Chad M. Schafer

2007-02-15T23:59:59.000Z

454

Functional Properties Staff  

Science Conference Proceedings (OSTI)

... Methods Group Staff; Materials Measurement Science Division Staff Directory; MML Organization. Contact. Functional Properties ...

2013-04-30T23:59:59.000Z

455

Transportation Organization and Functions  

Energy.gov (U.S. Department of Energy (DOE))

Office of Packaging and Transportation list of organizations and functions, with a list of acronyms.

456

Green's functions and hydrodynamics for isotopic binary diffusion  

E-Print Network (OSTI)

We study classical binary fluid mixtures in which densities vary on very short time (ps) and length (nm) scales, such that hydrodynamics does not apply. In a pure fluid with a localized heat pulse the breakdown of hydrodynamics was overcome using Green's functions which connect the initial densities to those at later times. Numerically it appeared that for long times the results from the Green's functions would approach hydrodynamics. In this paper we extend the Green's functions theory to binary mixtures. For the case of isothermal isobaric mutual diffusion in isotopic binary mixtures and ideal binary mixtures, which is easier to handle than heat conduction yet still non-trivial, we show analytically that in the Green's function approach one recovers hydrodynamic behaviour at long time scales provided the system reaches local equilibrium at long times. This is a first step toward giving the Green's function theory a firmer basis because it can for this case be considered as an extension of hydrodynamics.

R. van Zon; E. G. D. Cohen

2005-08-10T23:59:59.000Z

457

Metastable liquid-liquid coexistence and density anomalies in a core-softened fluid  

E-Print Network (OSTI)

Linearly-sloped or `ramp' potentials belong to a class of core-softened models which possess a liquid-liquid critical point (LLCP) in addition to the usual liquid-gas critical point. Furthermore they exhibit thermodynamic anomalies in the density and compressibility, the nature of which may be akin to those occurring in water. Previous simulation studies of ramp potentials have focused on just one functional form, for which the LLCP is thermodynamically stable. In this work we construct a series of ramp potentials, which interpolate between this previously studied form and a ramp-based approximation to the Lennard-Jones (LJ) potential. By means of Monte Carlo simulation, we locate the LLCP, the first order high density liquid (HDL)-low density liquid (LDL) coexistence line, and the line of density maxima for a selection of potentials in the series. We observe that as the LJ limit is approached, the LLCP becomes metastable with respect to freezing into a hexagonal close packed crystalline solid. The qualitative nature of the phase behaviour in this regime shows a remarkable resemblance to that seen in simulation studies of accurate water models. Specifically, the density of the liquid phase exceeds that of the solid; the gradient of the metastable LDL-HDL line is negative in the pressure (p)-temperature (T) plane; while the line of density maxima in the p-T plane has a shape similar to that seen in water and extends well into the {\\em stable} liquid region of the phase diagram. As such, our results lend weight to the `second critical point' hypothesis as an explanation for the anomalous behaviour of water.

Helen M. Gibson; Nigel B. Wilding

2006-01-20T23:59:59.000Z

458

The Quantum Energy Density: Improved Efficiency for Quantum Monte Carlo  

E-Print Network (OSTI)

We establish a physically meaningful representation of a quantum energy density for use in Quantum Monte Carlo calculations. The energy density operator, defined in terms of Hamiltonian components and density operators, returns the correct Hamiltonian when integrated over a volume containing a cluster of particles. This property is demonstrated for a helium-neon "gas," showing that atomic energies obtained from the energy density correspond to eigenvalues of isolated systems. The formation energies of defects or interfaces are typically calculated as total energy differences. Using a model of delta-doped silicon (where dopant atoms form a thin plane) we show how interfacial energies can be calculated more efficiently with the energy density, since the region of interest is small. We also demonstrate how the energy density correctly transitions to the bulk limit away from the interface where the correct energy is obtainable from a separate total energy calculation.

Krogel, Jaron T; Kim, Jeongnim; Ceperley, David M

2013-01-01T23:59:59.000Z

459

Nuclear symmetry energy at subnormal densities from measured nuclear masses  

E-Print Network (OSTI)

The symmetry energy coefficients for nuclei with mass number A=20~250 are extracted from more than 2000 measured nuclear masses. With the semi-empirical connection between the symmetry energy coefficients of finite nuclei and the nuclear symmetry energy at reference densities, we investigate the density dependence of symmetry energy of nuclear matter at subnormal densities. The obtained results are compared with those extracted from other methods.

Liu, Min; Li, Zhuxia; Zhang, Fengshou

2010-01-01T23:59:59.000Z

460

Nuclear symmetry energy at subnormal densities from measured nuclear masses  

E-Print Network (OSTI)

The symmetry energy coefficients for nuclei with mass number A=20~250 are extracted from more than 2000 measured nuclear masses. With the semi-empirical connection between the symmetry energy coefficients of finite nuclei and the nuclear symmetry energy at reference densities, we investigate the density dependence of symmetry energy of nuclear matter at subnormal densities. The obtained results are compared with those extracted from other methods.

Min Liu; Ning Wang; Zhuxia Li; Fengshou Zhang

2010-11-17T23:59:59.000Z

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461

Constraints on primordial density perturbations from induced gravitational waves  

SciTech Connect

We consider the stochastic background of gravitational waves produced during the radiation-dominated hot big bang as a constraint on the primordial density perturbation on comoving length scales much smaller than those directly probed by the cosmic microwave background or large-scale structure. We place weak upper bounds on the primordial density perturbation from current data. Future detectors such as BBO and DECIGO will place much stronger constraints on the primordial density perturbation on small scales.

Assadullahi, Hooshyar; Wands, David [Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Burnaby Road, Portsmouth PO1 3FX (United Kingdom)

2010-01-15T23:59:59.000Z

462

Method for measuring the density of lightweight materials  

DOE Patents (OSTI)

This invention relates to a nondestructive method for measuring the density of articles composed of elements having a low atomic number such as plastic and carbon composites. The measurement is accomplished by striking the article with a collimated beam of X radiation, simultaneously monitoring the radiation scattered and the radiation transmitted by the article, then relating the ratio of the radiation scattered to the radiation transmitted with the density of the article. The above method is insensitive to all variables except density.

Snow, Samuel G. (Oak Ridge, TN); Giacomelli, Edward J. (Knoxville, TN)

1980-01-01T23:59:59.000Z

463

Method for solvent extraction with near-equal density solutions  

DOE Patents (OSTI)

Disclosed is a modified centrifugal contactor for separating solutions of near equal density. The modified contactor has a pressure differential establishing means that allows the application of a pressure differential across fluid in the rotor of the contactor. The pressure differential is such that it causes the boundary between solutions of near-equal density to shift, thereby facilitating separation of the phases. Also disclosed is a method of separating solutions of near-equal density.

Birdwell, Joseph F. (Knoxville, TN); Randolph, John D. (Maryville, TN); Singh, S. Paul (Oak Ridge, TN)

2001-01-01T23:59:59.000Z

464

Effect of Chemical Pressure on the Charge Density Wave Transition...  

NLE Websites -- All DOE Office Websites (Extended Search)

at SSRL and the department of Applied Physics at Stanford University has determined the phase diagram of a new family of prototypical charge density wave (CDW) compounds. These...

465

Few transportation fuels surpass the energy densities of gasoline ...  

U.S. Energy Information Administration (EIA)

Natural gas, either in liquefied form (LNG) or compressed (CNG), are lighter than gasoline but again have lower densities per unit volume.

466

Few transportation fuels surpass the energy densities of ...  

U.S. Energy Information Administration (EIA)

Energy density and the cost, weight, and size of onboard energy storage are important characteristics of fuels for transportation. Fuels that require ...

467

Inexpensive Production of High Density Thin Ceramic Films on ...  

Steven Visco, Lutgard DeJonghe, and Craig Jacobson have developed a simple, inexpensive method for producing high density, crack-free, thin ceramic ...

468

047 Glass-Ceramic Composites for High Energy Density Capacitors  

Science Conference Proceedings (OSTI)

047 Glass-Ceramic Composites for High Energy Density Capacitors .... 150 Analysis of Hf-Ta Alloys for Oxidation Protection in Ultra High Temperature ...

469

Vibrated Bulk Density (VBD) of Calcined Petroleum Coke and ...  

Science Conference Proceedings (OSTI)

Presentation Title, Vibrated Bulk Density (VBD) of Calcined Petroleum Coke and Implications of Changes in the ASTM Method D4292. Author(s), Bill Spencer, ...

470

LINDENS: A program for lineament length and density ...  

Science Conference Proceedings (OSTI)

... or horizontal strata, lineaments are related to fractures and faults ... give an idea of the fracture pattern of ... and density analysis of recent fracturing in the ...

2013-07-15T23:59:59.000Z

471

Variational Two-electron Reduced Density Matrix Theory for Many ...  

E-Print Network (OSTI)

Sep 16, 2005 ... Abstract: The energy and properties of a many-electron atom or ... of a two- electron reduced density matrix (2-RDM) that is constrained to ...

472

The Reduced Density Matrix Method for Electronic Structure ...  

E-Print Network (OSTI)

Oct 14, 2003 ... This suggested to Mayer that the ground state energy. – and density matrix information – could be economically computed by simply carrying ...

473

City of Seattle - Density Bonus for Green Buildings (Washington...  

Open Energy Info (EERE)

Edit with form History Share this page on Facebook icon Twitter icon City of Seattle - Density Bonus for Green Buildings (Washington) This is the approved revision of...

474

Aluminum Oxynitride Dielectrics for High Energy Density Capacitor ...  

Science Conference Proceedings (OSTI)

Oct 15, 2006 ... Aluminum Oxynitride Dielectrics for High Energy Density Capacitor Applications by Kevin R. Bray, Richard L.C. Wu, Sandra Fries-Carr, and ...

475

Hybrid Aluminum-Lithium Ion Battery having Enhanced Power Density  

Hybrid Aluminum-Lithium Ion Battery having Enhanced Power Density Note: The technology described above is an early stage opportunity. Licensing rights to this ...

476

Device Fabrication Method for High Power Density Capacitors  

Device Fabrication Method for High Power Density Capacitors Note: The technology described above is an early stage opportunity. Licensing rights to this intellectual ...

477

3-D capacitance density imaging of fluidized bed  

DOE Patents (OSTI)

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.

Fasching, George E. (653 Vista Pl., Morgantown, WV 26505)

1990-01-01T23:59:59.000Z

478

CORRELATION BETWEEN GROUP LOCAL DENSITY AND GROUP LUMINOSITY  

SciTech Connect

In this study, we investigate the correlation between group local number density and total luminosity of groups. In four volume-limited group catalogs, we can conclude that groups with high luminosity exist preferentially in high-density regions, while groups with low luminosity are located preferentially in low-density regions, and that in a volume-limited group sample with absolute magnitude limit M{sub r} = -18, the correlation between group local number density and total luminosity of groups is the weakest. These results basically are consistent with the environmental dependence of galaxy luminosity.

Deng Xinfa [School of Science, Nanchang University, Jiangxi 330031 (China); Yu Guisheng [Department of Natural Science, Nanchang Teachers College, Jiangxi 330103 (China)

2012-11-10T23:59:59.000Z

479

Amplifying Magnetic Fields in High Energy Density Plasmas | U...  

Office of Science (SC) Website

Amplifying Magnetic Fields in High Energy Density Plasmas Fusion Energy Sciences (FES) FES Home About Research Facilities Science Highlights Benefits of FES Funding Opportunitie