A Bme Solution Of The Stochastic Three-Dimensional Laplace Equation...
Solution Of The Stochastic Three-Dimensional Laplace Equation Representing A Geothermal Field Subject To Site-Specific Information Abstract This work develops a model of the...
Expansion solution of Laplace`s equation: Technique and application to hollow beam gun design
Jackson, R.H.; Taccetti, J.M.
1996-12-31
This paper presents a flexible algorithm for the general calculation of expansion solutions to Laplace`s equation. The limiting factor in application of the technique is shown to be series truncation error and not errors in calculating numerical derivatives. Application of the algorithm to the accurate computation of arbitrary magnetic fields in cylindrical geometry from on-axis or coil data will be presented. For an ideal current loop, magnetic field accuracies of better than 0.01% of the exact elliptic integral solution can be obtained out to approximately 70--80% of the loop radius. Accuracy improves dramatically for radii closer to the axis. Results also is shown for thin current disks, thin solenoids and thick coils. Other aspects of the technique is illustrated by application to the design of a coil system for a hollow beam electron gun. With some reasonable assumptions about the overlay of the electron trajectories and the magnetic flux contours, it is possible to generate an estimate for the on-axis profile of the gun magnetic field. The expansion technique can then be applied to calculate the off-axis field and its impact on the trajectories without assuming any particular coil system. The initial estimate can then be refined and retested. Finally, an optimization technique is used to develop a coil system which closely reproduces the refined field. The results of carrying out this set of calculations on a 150 kV, 20 A hollow electron gun design for an FEL experiment is reported.
Shao, Yan-Lin Faltinsen, Odd M.
2014-10-01
We propose a new efficient and accurate numerical method based on harmonic polynomials to solve boundary value problems governed by 3D Laplace equation. The computational domain is discretized by overlapping cells. Within each cell, the velocity potential is represented by the linear superposition of a complete set of harmonic polynomials, which are the elementary solutions of Laplace equation. By its definition, the method is named as Harmonic Polynomial Cell (HPC) method. The characteristics of the accuracy and efficiency of the HPC method are demonstrated by studying analytical cases. Comparisons will be made with some other existing boundary element based methods, e.g. Quadratic Boundary Element Method (QBEM) and the Fast Multipole Accelerated QBEM (FMA-QBEM) and a fourth order Finite Difference Method (FDM). To demonstrate the applications of the method, it is applied to some studies relevant for marine hydrodynamics. Sloshing in 3D rectangular tanks, a fully-nonlinear numerical wave tank, fully-nonlinear wave focusing on a semi-circular shoal, and the nonlinear wave diffraction of a bottom-mounted cylinder in regular waves are studied. The comparisons with the experimental results and other numerical results are all in satisfactory agreement, indicating that the present HPC method is a promising method in solving potential-flow problems. The underlying procedure of the HPC method could also be useful in other fields than marine hydrodynamics involved with solving Laplace equation.
Introduction to Control Theory. Part 2. Laplace Transforms and Linear Systems
Scheinker, Alexander
2015-09-11
Presentation for summer students. Start by considering linear differential equations, and how to solve them. The Laplace Transform is a great tool for solving linear differential equations.
Energy Science and Technology Software Center (OSTI)
2008-10-05
Laplace is a electric field driven flow simulation program for detailed device design support. Transport processes include electrokinesis, dielectrophoresis, and diffusion. Laplace solves for the electric field in a microfluidic system and the liquid and particle flow that is produced by the electric field for the primary purpose of microfluidic design development and simulation. Laplace allows you to visualize the flow by tracking tracer particles, viewing flow streamlines, etc. Laplace can make movies of simulatedmore » particle motion to allow you to test and share the behavior of microfuidic designs. The electric field is calculated using an iterative linear solver and particle motion is solved by finite difference, finite-displacement simulation of particle trajectories. Laplace uses a bitmapped picture or drawing of a microsystem to infer the geometry. The channel depth is everywhere proportional to the magnitude of the blue channel of the image: 0 (black) = zero depth, or no channel, 256 (saturated blue) = deepest channel, and intermediate values correspond to intermediate depths. Laplace automatically applies various boundary conditions (applied voltage or current) to ports, where channels cross the edge of the image.« less
Laplace-Runge-Lenz vector for arbitrary spin
Nikitin, A. G.
2013-12-15
A countable set of superintegrable quantum mechanical systems is presented which admit the dynamical symmetry with respect to algebra so(4). This algebra is generated by the Laplace-Runge-Lenz vector generalized to the case of arbitrary spin. The presented systems describe neutral particles with non-trivial multipole momenta. Their spectra can be found algebraically like in the case of hydrogen atom. Solutions for the systems with spins 1/2 and 1 are presented explicitly, solutions for spin 3/2 can be expressed via solutions of an ordinary differential equation of first order. A more extended version of this paper including detailed calculations is published as an e-print arXiv:1308.4279.
Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]
2011-03-01
This standard, DOE-STD-1063, Facility Representatives, defines the duties, responsibilities and qualifications for Department of Energy (DOE) Facility Representatives, based on facility hazard classification; risks to workers, the public, and the environment; and the operational activity level. This standard provides the guidance necessary to ensure that DOE’s hazardous nuclear and non-nuclear facilities have sufficient staffing of technically qualified facility representatives (FRs) to provide day-to-day oversight of contractor operations.
Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]
2006-04-06
REPLACED BY DOE-STD-1063 | SUPERSEDING DOE-STD-1063-2000 (MARCH 2000) The purpose of the DOE Facility Representative Program is to ensure that competent DOE staff personnel are assigned to oversee the day-to-day contractor operations at DOE’s hazardous nuclear and non-nuclear facilities.
Laplace plane modifications arising from solar radiation pressure
Rosengren, Aaron J.; Scheeres, Daniel J.
2014-05-01
The dynamical effects of solar radiation pressure (SRP) in the solar system have been rigorously studied since the early 1900s. This non-gravitational perturbation plays a significant role in the evolution of dust particles in circumplanetary orbits, as well as in the orbital motion about asteroids and comets. For gravitationally dominated orbits, SRP is negligible and the resulting motion is largely governed by the oblateness of the primary and the attraction of the Sun. The interplay between these gravitational perturbations gives rise to three mutually perpendicular planes of equilibrium for circular satellite orbits. The classical Laplace plane lies between the equatorial and orbital planes of the primary, and is the mean reference plane about whose axis the pole of a satellite's orbit precesses. From a previously derived solution for the secular motion of an orbiter about a small body in a SRP dominated environment, we find that SRP acting alone will cause an initially circular orbit to precess around the pole of the primary's heliocentric orbital plane. When the gravitational and non-gravitational perturbations act in concert, the resulting equilibrium planes turn out to be qualitatively different, in some cases, from those obtained without considering the radiation pressure. The warping of the surfaces swept out by the modified equilibria as the semi-major axis varies depends critically on the cross-sectional area of the body exposed. These results, together with an adiabatic invariance argument on Poynting-Robertson drag, provide a natural qualitative explanation for the initial albedo dichotomy of Saturn's moon, Iapetus.
063-2011 February 2011 Superseding DOE-STD-1063-2006 April 2006 DOE STANDARD FACILITY REPRESENTATIVES U.S. Department of Energy AREA MGMT Washington, D.C. 20585 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. NOT MEASUREMENT SENSITIVE DOE-STD-1063-2011 ii Available on the Department of Energy Technical Standards Program Web site at http://www.hss.doe.gov/nuclearsafety/ns/techstds/ DOE-STD-1063-2011 iii FOREWORD 1. This Department of Energy (DOE) standard is
Temme, N.M.
1987-11-01
The analytical approach of Temme (1983 and 1985), based on uniform asymptotic expansions, is extended to an additional class of incomplete Laplace integrals. The terminology is introduced; the construction of the formal series is explained; representations for the remainders are derived; the asymptotic nature of the expansions is explored; and error bounds are determined. Numerical results are presented for the case of the incomplete beta function. 14 references.
house of representatives | National Nuclear Security Administration
National Nuclear Security Administration (NNSA)
house of representatives
Sadybekov, Makhmud A.; Torebek, Berikbol T.; Turmetov, Batirkhan Kh.
2014-08-20
The paper is devoted to the investigation of questions about constructing the explicit form of the Greens function of the Robin problem. For constructing this function we use the representation of the fundamental solution of the Laplace equation in the form of a series. An integral representation of the Green function is obtained and for some values of the parameters, the problem is presented in elementary functions.
UESC Training for Utility Representatives
Broader source: Energy.gov [DOE]
Provides utility representatives with additional training to meet their responsibilities with respect to Utility Energy Savings Contracts (UESC).
CRAD, NNSA- Facility Representatives (FR)
Office of Energy Efficiency and Renewable Energy (EERE)
CRAD for Facility Representatives (FR). Criteria Review and Approach Documents (CRADs) that can be used to conduct a well-organized and thorough assessment of elements of safety and health programs.
TEC Working Group Member Organizations Representatives | Department...
Office of Environmental Management (EM)
Member Organizations Representatives TEC Working Group Member Organizations Representatives PDF icon TEC MEMBER ORGANIZATION REPRESENTATIVES TOPIC GROUP PARTICIPATION February 2006...
Facility Representative Qualification Equivalencies Based on...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Facility Representative Qualification Equivalencies Based on Previous Experience Facility Representative Qualification Equivalencies Based on Previous Experience The referenced ...
SIMULTANEOUS DIFFERENTIAL EQUATION COMPUTER
Collier, D.M.; Meeks, L.A.; Palmer, J.P.
1960-05-10
A description is given for an electronic simulator for a system of simultaneous differential equations, including nonlinear equations. As a specific example, a homogeneous nuclear reactor system including a reactor fluid, heat exchanger, and a steam boiler may be simulated, with the nonlinearity resulting from a consideration of temperature effects taken into account. The simulator includes three operational amplifiers, a multiplier, appropriate potential sources, and interconnecting R-C networks.
Relativistic Guiding Center Equations
White, R. B.; Gobbin, M.
2014-10-01
In toroidal fusion devices it is relatively easy that electrons achieve relativistic velocities, so to simulate runaway electrons and other high energy phenomena a nonrelativistic guiding center formalism is not sufficient. Relativistic guiding center equations including flute mode time dependent field perturbations are derived. The same variables as used in a previous nonrelativistic guiding center code are adopted, so that a straightforward modifications of those equations can produce a relativistic version.
Authorizing Official Designated Representative (AODR) | Department of
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Energy Designated Representative (AODR) Authorizing Official Designated Representative (AODR) student-849822_960_720.jpg The Authorizing Official Designated Representative (AODR) provides technical and organizational support to the Authorizing Official (AO). Individual(s) in the AO Representative role must possess a working knowledge of: system function security policies technical security safeguards PDF icon AODR
Property Representatives Lists - HQ | Department of Energy
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Property Representatives Lists - HQ Property Representatives Lists - HQ These are the current lists of Headquarters Property Representatives. If you have any questions please contact: Ellen Hall, Office of Logistics Operations, (301) 903-2613. PDF icon Authorized Property Pass Signers List and Accountable Property Representatives List, Effective April 1, 2016 More Documents & Publications Directory Listings AU Functional Area Points of Contact by Office Directors Headquarters Facilities
Parallel Multigrid Equation Solver
Energy Science and Technology Software Center (OSTI)
2001-09-07
Prometheus is a fully parallel multigrid equation solver for matrices that arise in unstructured grid finite element applications. It includes a geometric and an algebraic multigrid method and has solved problems of up to 76 mullion degrees of feedom, problems in linear elasticity on the ASCI blue pacific and ASCI red machines.
Flavored quantum Boltzmann equations
Cirigliano, Vincenzo; Lee, Christopher; Ramsey-Musolf, Michael J.; Tulin, Sean [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico, 87545 (United States); Center for Theoretical Physics, University of California, and Theoretical Physics Group, Lawrence Berkeley National Laboratory, Berkeley, California, 94720 (United States); Department of Physics, University of Wisconsin-Madison, 1150 University Avenue, Madison, Wisconsin, 53706 (United States) and Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, California, 91125 (United States); Theory Group, TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, V6T 2A3 (Canada)
2010-05-15
We derive from first principles, using nonequilibrium field theory, the quantum Boltzmann equations that describe the dynamics of flavor oscillations, collisions, and a time-dependent mass matrix in the early universe. Working to leading nontrivial order in ratios of relevant time scales, we study in detail a toy model for weak-scale baryogenesis: two scalar species that mix through a slowly varying time-dependent and CP-violating mass matrix, and interact with a thermal bath. This model clearly illustrates how the CP asymmetry arises through coherent flavor oscillations in a nontrivial background. We solve the Boltzmann equations numerically for the density matrices, investigating the impact of collisions in various regimes.
Facility Representative Program Outstanding at ID
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
June 19, 2007 Facility Representative Program Outstanding at ID Idaho's three DOE Complex-wide Facility Representative of the Year (FROTY) recipients at this year's conference pose for a photo shoot with Elvis. L to R: Dary Newbry 2005 FROTY, Bob Seal 2006 FROTY, Bob Knighten 2004 FROTY Facility representatives (FRs) are the eyes and ears of the federal government at the Idaho National Laboratory. They oversee the people, processes, facilities and systems that ensure safety at INL facilities.
Facility Representative Qualification Equivalencies Based on Previous
Experience | Department of Energy Facility Representative Qualification Equivalencies Based on Previous Experience Facility Representative Qualification Equivalencies Based on Previous Experience The referenced document has been used by the Department of Energy, Idaho Operations Office (DOE-ID) to grant equivalencies to candidates undergoing qualification as a Facility Representative (FR) using the FR Functional Area Qualification Standards (FAQS). Since the generation of the referenced
DOE RL Contracting Officer Representatives - Hanford Site
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Officer Representatives DOE-RL Contracts/Procurements RL Contracts & Procurements Home Prime Contracts Current Solicitations Other Sources DOE RL Contracting Officers DOE RL Contracting Officer Representatives DOE RL Contracting Officer Representatives Email Email Page | Print Print Page |Text Increase Font Size Decrease Font Size CO/COR Contract Number Company Acronym Limitations CAROSINO, ROBERT M DE-AC06-08RL14788 CPRC DE-AC06-08RL14788, CH2M HILL PLATEAU REMEDIATION COMPANY (CHPRC),
FAQS Reference Guide – Facility Representative
Broader source: Energy.gov [DOE]
This reference guide addresses the competency statements in the October 2010 edition of DOE-STD-1151-2010, Facility Representative Functional Area Qualification Standard.
Departmental Representative to the Defense Nuclear Facilities...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
The Office of the Departmental Representative ensures effective cross-organizational leadership and coordination to resolve DNFSB-identified technical and management issues as we ...
Nazari-Golshan, A.; Nourazar, S. S.; Department of Mechanical Engineering, Amirkabir University of Technology, Tehran
2013-10-15
The time fractional modified Korteweg-de Vries (TFMKdV) equation is solved to study the nonlinear propagation of small but finite amplitude dust ion-acoustic (DIA) solitary waves in un-magnetized dusty plasma with trapped electrons. The plasma is composed of a cold ion fluid, stationary dust grains, and hot electrons obeying a trapped electron distribution. The TFMKdV equation is derived by using the semi-inverse and Agrawal's methods and then solved by the Laplace Adomian decomposition method. Our results show that the amplitude of the DIA solitary waves increases with the increase of time fractional order ?, the wave velocity v{sub 0}, and the population of the background free electrons ?. However, it is vice-versa for the deviation from isothermality parameter b, which is in agreement with the result obtained previously.
Facility Representative Program, Criteria & Review Approach Documents
Broader source: Energy.gov [DOE]
This page provides Criteria Review and Approach Documents (CRADS) to assist Facility Representatives. Please submit your CRADS for posting by sending them to the HQ FR Program Manager. Please include the subject, date, and a contact person.
Advisory Board Seats New Student Representatives
Broader source: Energy.gov [DOE]
The Oak Ridge Site Specific Advisory Board (ORSSAB) welcomed two new student representatives at its May meeting. Gracie Hall and Julia Riley will serve on the board through April 2014.
Incentives for the Department's Facility Representative Program,
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
12/17/1998 | Department of Energy Incentives for the Department's Facility Representative Program, 12/17/1998 Incentives for the Department's Facility Representative Program, 12/17/1998 The Department's Revised Implementation Plan for Defense Nuclear Facilities Safety Board Recommendation 93-3 has once again underscored the Department's commitment to maintaining the technical capability necessary to safely manage and operate our defense nuclear facilities. Attracting and retaining highly
A Least-Squares Transport Equation Compatible with Voids
Hansen, Jon [Texas A & M Univ., College Station, TX (United States). Dept. of Nuclear Engineering; Peterson, Jacob [Texas A & M Univ., College Station, TX (United States). Dept. of Nuclear Engineering; Morel, Jim [Texas A & M Univ., College Station, TX (United States). Dept. of Nuclear Engineering; Ragusa, Jean [Texas A & M Univ., College Station, TX (United States). Dept. of Nuclear Engineering; Wang, Yaqi [Idaho National Lab. (INL), Idaho Falls, ID (United States)
2014-12-01
Standard second-order self-adjoint forms of the transport equation, such as the even-parity, odd-parity, and self-adjoint angular flux equation, cannot be used in voids. Perhaps more important, they experience numerical convergence difficulties in near-voids. Here we present a new form of a second-order self-adjoint transport equation that has an advantage relative to standard forms in that it can be used in voids or near-voids. Our equation is closely related to the standard least-squares form of the transport equation with both equations being applicable in a void and having a nonconservative analytic form. However, unlike the standard least-squares form of the transport equation, our least-squares equation is compatible with source iteration. It has been found that the standard least-squares form of the transport equation with a linear-continuous finite-element spatial discretization has difficulty in the thick diffusion limit. Here we extensively test the 1D slab-geometry version of our scheme with respect to void solutions, spatial convergence rate, and the intermediate and thick diffusion limits. We also define an effective diffusion synthetic acceleration scheme for our discretization. Our conclusion is that our least-squares S_{n} formulation represents an excellent alternative to existing second-order S_{n} transport formulations
Menikoff, Ralph
2015-12-15
The JWL equation of state (EOS) is frequently used for the products (and sometimes reactants) of a high explosive (HE). Here we review and systematically derive important properties. The JWL EOS is of the Mie-Grueneisen form with a constant Grueneisen coefficient and a constants specific heat. It is thermodynamically consistent to specify the temperature at a reference state. However, increasing the reference state temperature restricts the EOS domain in the (V, e)-plane of phase space. The restrictions are due to the conditions that P ? 0, T ? 0, and the isothermal bulk modulus is positive. Typically, this limits the low temperature regime in expansion. The domain restrictions can result in the P-T equilibrium EOS of a partly burned HE failing to have a solution in some cases. For application to HE, the heat of detonation is discussed. Example JWL parameters for an HE, both products and reactions, are used to illustrate the restrictions on the domain of the EOS.
Data structures and apparatuses for representing knowledge
Hohimer, Ryan E; Thomson, Judi R; Harvey, William J; Paulson, Patrick R; Whiting, Mark A; Tratz, Stephen C; Chappell, Alan R; Butner, Robert S
2014-02-18
Data structures and apparatuses to represent knowledge are disclosed. The processes can comprise labeling elements in a knowledge signature according to concepts in an ontology and populating the elements with confidence values. The data structures can comprise knowledge signatures stored on computer-readable media. The knowledge signatures comprise a matrix structure having elements labeled according to concepts in an ontology, wherein the value of the element represents a confidence that the concept is present in an information space. The apparatus can comprise a knowledge representation unit having at least one ontology stored on a computer-readable medium, at least one data-receiving device, and a processor configured to generate knowledge signatures by comparing datasets obtained by the data-receiving devices to the ontologies.
Facility Representative Functional Area Qualification Standard
DOE-STD-1151-2010 October 2010 DOE STANDARD FACILITY REPRESENTATIVE FUNCTIONAL AREA QUALIFICATION STANDARD DOE Defense Nuclear Facilities Technical Personnel U.S. Department of Energy AREA TRNG Washington, D.C. 20585 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. DOE-STD-1151-2010 ii This document is available on the Department of Energy Office of Health, Safety and Security Approved DOE Technical Standards Web Site at
DOE ORP Contracting Officer Representatives - Hanford Site
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
DOE ORGANIZATION CHART - FEBRUARY 2016 DOE ORGANIZATION CHART - FEBRUARY 2016 The DOE Organization Chart is a diagram of the U.S. Department of Energy's structure along with the relationships and relative ranks of its parts and positions/jobs. PDF icon DOECHART-NONAMES-2016-February-22.pdf More Documents & Publications DOE ORGANIZATION CHART - JANUARY 2016 DOE Organization Chart - December 2014 DOE Organization Chart - February 2015
DOE ORP Contracting Officer Representatives Office of
Yucca Mountain Climate Technical Support Representative
Sharpe, Saxon E
2007-10-23
The primary objective of Project Activity ORD-FY04-012, Yucca Mountain Climate Technical Support Representative, was to provide the Office of Civilian Radioactive Waste Management (OCRWM) with expertise on past, present, and future climate scenarios and to support the technical elements of the Yucca Mountain Project (YMP) climate program. The Climate Technical Support Representative was to explain, defend, and interpret the YMP climate program to the various audiences during Site Recommendation and License Application. This technical support representative was to support DOE management in the preparation and review of documents, and to participate in comment response for the Final Environmental Impact Statement, the Site Recommendation Hearings, the NRC Sufficiency Comments, and other forums as designated by DOE management. Because the activity was terminated 12 months early and experience a 27% reduction in budget, it was not possible to complete all components of the tasks as originally envisioned. Activities not completed include the qualification of climate datasets and the production of a qualified technical report. The following final report is an unqualified summary of the activities that were completed given the reduced time and funding.
PWR representative behavior during a LOCA
Allison, C.M.
1981-01-01
To date, there has been substantial analytical and experimental effort to define the margins between design basis loss-of-coolant accident (LOCA) behavior and regulatory limits on maximum fuel rod cladding temperature and deformation. As a result, there is extensive documentation on the modeling of fuel rod behavior in test reactors and design basis LOCA's. However, modeling of that behavior using representative, non-conservative, operating histories is not nearly as well documented in the public literature. Therefore, the objective of this paper is (a) to present calculations of LOCA induced behavior for Pressurized Water Reactor (PWR) core representative fuel rods, and (b) to discuss the variability in those calculations given the variability in fuel rod condition at the initiation of the LOCA. This analysis was limited to the study of changes in fuel rod behavior due to different power operating histories. The other two important parameters which affect that behavior, initial fuel rod design and LOCA coolant conditions were held invarient for all of the representative rods analyzed.
Generalizing the cosmic energy equation
Shtanov, Yuri; Sahni, Varun
2010-11-15
We generalize the cosmic energy equation to the case when massive particles interact via a modified gravitational potential of the form {phi}(a,r), which is allowed to explicitly depend upon the cosmological time through the expansion factor a(t). Using the nonrelativistic approximation for particle dynamics, we derive the equation for the cosmological expansion which has the form of the Friedmann equation with a renormalized gravitational constant. The generalized Layzer-Irvine cosmic energy equation and the associated cosmic virial theorem are applied to some recently proposed modifications of the Newtonian gravitational interaction between dark-matter particles. We also draw attention to the possibility that the cosmic energy equation may be used to probe the expansion history of the universe thereby throwing light on the nature of dark matter and dark energy.
Point model equations for neutron correlation counting: Extension of Böhnel's equations to any order
Favalli, Andrea; Croft, Stephen; Santi, Peter
2015-06-15
Various methods of autocorrelation neutron analysis may be used to extract information about a measurement item containing spontaneously fissioning material. The two predominant approaches being the time correlation analysis (that make use of a coincidence gate) methods of multiplicity shift register logic and Feynman sampling. The common feature is that the correlated nature of the pulse train can be described by a vector of reduced factorial multiplet rates. We call these singlets, doublets, triplets etc. Within the point reactor model the multiplet rates may be related to the properties of the item, the parameters of the detector, and basic nuclear data constants by a series of coupled algebraic equations – the so called point model equations. Solving, or inverting, the point model equations using experimental calibration model parameters is how assays of unknown items is performed. Currently only the first three multiplets are routinely used. In this work we develop the point model equations to higher order multiplets using the probability generating functions approach combined with the general derivative chain rule, the so called Faà di Bruno Formula. Explicit expression up to 5th order are provided, as well the general iterative formula to calculate any order. This study represents the first necessary step towards determining if higher order multiplets can add value to nondestructive measurement practice for nuclear materials control and accountancy.
Point model equations for neutron correlation counting: Extension of Böhnel's equations to any order
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Favalli, Andrea; Croft, Stephen; Santi, Peter
2015-06-15
Various methods of autocorrelation neutron analysis may be used to extract information about a measurement item containing spontaneously fissioning material. The two predominant approaches being the time correlation analysis (that make use of a coincidence gate) methods of multiplicity shift register logic and Feynman sampling. The common feature is that the correlated nature of the pulse train can be described by a vector of reduced factorial multiplet rates. We call these singlets, doublets, triplets etc. Within the point reactor model the multiplet rates may be related to the properties of the item, the parameters of the detector, and basic nuclearmore » data constants by a series of coupled algebraic equations – the so called point model equations. Solving, or inverting, the point model equations using experimental calibration model parameters is how assays of unknown items is performed. Currently only the first three multiplets are routinely used. In this work we develop the point model equations to higher order multiplets using the probability generating functions approach combined with the general derivative chain rule, the so called Faà di Bruno Formula. Explicit expression up to 5th order are provided, as well the general iterative formula to calculate any order. This study represents the first necessary step towards determining if higher order multiplets can add value to nondestructive measurement practice for nuclear materials control and accountancy.« less
1998 Annual Facility Representative Workshop Attendees
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
998 Annual Facility Representative Workshop Attendees Last Name First Office Location Phone Fax E-Mail Alvord Bob OAK LLNL (925) 422-0830 (925) 422-0832 robert.alvord@oak.doe.gov Barnes John SR SRTC (803) 208-2628 (803) 208-1123 johnc.barnes@srs.gov Bell Fred AL LAAO (505) 665-4856 (505) 665-9230 fbell@doeal.gov Bell Bill AL LAAO (505) 665-6324 (505) 665-9230 bbell@doeal.gov Bennett Rick RF DOE (303) 966-8155 (303) 966-7447 rick.bennett@rfets.gov Biro Brian RL LABS (509) 376-7660 (509) 376-9837
Friedmann equations from entropic force
Cai Ronggen; Cao Liming; Ohta, Nobuyoshi
2010-03-15
In this paper, by use of the holographic principle together with the equipartition law of energy and the Unruh temperature, we derive the Friedmann equations of a Friedmann-Robertson-Walker universe.
Entropic corrections to Einstein equations
Hendi, S. H. [Physics Department, College of Sciences, Yasouj University, Yasouj 75914 (Iran, Islamic Republic of); Research Institute for Astronomy and Astrophysics of Maragha (RIAAM), Maragha (Iran, Islamic Republic of); Sheykhi, A. [Research Institute for Astronomy and Astrophysics of Maragha (RIAAM), Maragha (Iran, Islamic Republic of); Department of Physics, Shahid Bahonar University, P.O. Box 76175-132, Kerman (Iran, Islamic Republic of)
2011-04-15
Considering the general quantum corrections to the area law of black hole entropy and adopting the viewpoint that gravity interprets as an entropic force, we derive the modified forms of Modified Newtonian dynamics (MOND) theory of gravitation and Einstein field equations. As two special cases we study the logarithmic and power-law corrections to entropy and find the explicit form of the obtained modified equations.
Microsoft Word - SEC J_Appendix S- Contracting Officer's Representative_s_
National Nuclear Security Administration (NNSA)
J, Page 1 SECTION J APPENDIX S CONTRACTING OFFICER REPRESENTATIVES The following individuals are designated as CORs for the Kansas City Plant Contract. Each is limited to the specific areas listed by his/her name. Contracting Officer Representatives Name Location Limited Area of Responsibility Shoulta, Jeffrey L. KCSO Production & Quality Management Hoopes, Patrick T. KCSO Environment, Safety and Health; Facilities Management; Security and Information Systems Schmidt, Robert E. KCSO Project
Illite Dissolution Rates and Equation (100 to 280 dec C)
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Carroll, Susan
The objective of this suite of experiments was to develop a useful kinetic dissolution expression for illite applicable over an expanded range of solution pH and temperature conditions representative of subsurface conditions in natural and/or engineered geothermal reservoirs. Using our new data, the resulting rate equation is dependent on both pH and temperature and utilizes two specific dissolution mechanisms (a neutral and a basic mechanism). The form of this rate equation should be easily incorporated into most existing reactive transport codes for to predict rock-water interactions in EGS shear zones.
Thermodynamically constrained correction to ab initio equations of state
French, Martin; Mattsson, Thomas R.
2014-07-07
We show how equations of state generated by density functional theory methods can be augmented to match experimental data without distorting the correct behavior in the high- and low-density limits. The technique is thermodynamically consistent and relies on knowledge of the density and bulk modulus at a reference state and an estimation of the critical density of the liquid phase. We apply the method to four materials representing different classes of solids: carbon, molybdenum, lithium, and lithium fluoride. It is demonstrated that the corrected equations of state for both the liquid and solid phases show a significantly reduced dependence of the exchange-correlation functional used.
Illite Dissolution Rates and Equation (100 to 280 dec C)
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Carroll, Susan
2014-10-17
The objective of this suite of experiments was to develop a useful kinetic dissolution expression for illite applicable over an expanded range of solution pH and temperature conditions representative of subsurface conditions in natural and/or engineered geothermal reservoirs. Using our new data, the resulting rate equation is dependent on both pH and temperature and utilizes two specific dissolution mechanisms (a neutral and a basic mechanism). The form of this rate equation should be easily incorporated into most existing reactive transport codes for to predict rock-water interactions in EGS shear zones.
Illite Dissolution Rates and Equation (100 to 280 dec C)
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Carroll, Susan
2014-10-17
The objective of this suite of experiments was to develop a useful kinetic dissolution expression for illite applicable over an expanded range of solution pH and temperature conditions representative of subsurface conditions in natural and/or engineered geothermal reservoirs. Using our new data, the resulting rate equation is dependent on both pH and temperature and utilizes two specific dissolution mechanisms (a “neutral” and a “basic” mechanism). The form of this rate equation should be easily incorporated into most existing reactive transport codes for to predict rock-water interactions in EGS shear zones.
1998 Annual Facility Representative Workshop Attendees | Department of
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Energy 998 Annual Facility Representative Workshop Attendees 1998 Annual Facility Representative Workshop Attendees 1998 Annual Facility Representative Workshop Attendees PDF icon 1998 Annual Facility Representative Workshop Attendees More Documents & Publications 1999 Annual Facility Representative Workshop Attendees FTCP Members DOE ISM Champions - 2012
1999 Annual Facility Representative Workshop Attendees | Department of
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Energy 999 Annual Facility Representative Workshop Attendees 1999 Annual Facility Representative Workshop Attendees 1997 Annual Facility Representative Workshop Attendees PDF icon 1997 Annual Facility Representative Workshop Attendees More Documents & Publications 1998 Annual Facility Representative Workshop Attendees FTCP Members DOE ISM Champions - 2012
Ordinary Differential Equation System Solver
Energy Science and Technology Software Center (OSTI)
1992-03-05
LSODE is a package of subroutines for the numerical solution of the initial value problem for systems of first order ordinary differential equations. The package is suitable for either stiff or nonstiff systems. For stiff systems the Jacobian matrix may be treated in either full or banded form. LSODE can also be used when the Jacobian can be approximated by a band matrix.
3Q CY2005 (PDF), Facility Representative Program Performance...
Office of Environmental Management (EM)
3Q CY2005 (PDF), Facility Representative Program Performance Indicators Quarterly Report 3Q CY2005 (PDF), Facility Representative Program Performance Indicators Quarterly Report...
Representativeness-based Sampling Network Design for the State...
Office of Scientific and Technical Information (OSTI)
Representativeness-based Sampling Network Design for the State of Alaska Citation Details In-Document Search Title: Representativeness-based Sampling Network Design for the State...
Representativeness based Sampling Network Design for the State...
Office of Scientific and Technical Information (OSTI)
Representativeness based Sampling Network Design for the State of Alaska Title: Representativeness-based Sampling Network Design for the State of Alaska Authors: Forrest M. Hoffman...
Representativeness-Based Sampling Network Design for the State...
Office of Scientific and Technical Information (OSTI)
Journal Article: Representativeness-Based Sampling Network Design for the State of Alaska Citation Details In-Document Search Title: Representativeness-Based Sampling Network...
1Q CY2000 (PDF), Facility Representative Program Performance...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Facility Representatives Standard, DOE-STD-1 063, and reported to Headquarters Program Offices for evaluation and feedback in order to improve the Facility Representative Program. ...
Facility Representative Program ID Selects FR of the Year
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Facility Representative Program ID Selects FR of the Year John Martin DOE-ID Facility Representative John Martin DOE-ID Facility Representative of the Year. John Martin was selected as DOE-ID's Facility Representative of the Year and the office's nominee for the 2007 DOE Facility Representative of the Year Award. John was selected from an exceptional field of candidates to represent DOE-ID at the Facility Representative Annual Workshop in Las Vegas this May. Each year the Department of Energy
Equation of State Project Overview
Crockett, Scott
2015-09-11
A general overview of the Equation of State (EOS) Project will be presented. The goal is to provide the audience with an introduction of what our more advanced methods entail (DFT, QMD, etc.. ) and how these models are being utilized to better constrain the thermodynamic models. These models substantially reduce our regions of interpolation between the various thermodynamic limits. I will also present a variety example of recent EOS work.
Nguyen, Dang Van; Li, Jing-Rebecca; Grebenkov, Denis; Le Bihan, Denis
2014-04-15
The complex transverse water proton magnetization subject to diffusion-encoding magnetic field gradient pulses in a heterogeneous medium can be modeled by the multiple compartment Bloch–Torrey partial differential equation (PDE). In addition, steady-state Laplace PDEs can be formulated to produce the homogenized diffusion tensor that describes the diffusion characteristics of the medium in the long time limit. In spatial domains that model biological tissues at the cellular level, these two types of PDEs have to be completed with permeability conditions on the cellular interfaces. To solve these PDEs, we implemented a finite elements method that allows jumps in the solution at the cell interfaces by using double nodes. Using a transformation of the Bloch–Torrey PDE we reduced oscillations in the searched-for solution and simplified the implementation of the boundary conditions. The spatial discretization was then coupled to the adaptive explicit Runge–Kutta–Chebyshev time-stepping method. Our proposed method is second order accurate in space and second order accurate in time. We implemented this method on the FEniCS C++ platform and show time and spatial convergence results. Finally, this method is applied to study some relevant questions in diffusion MRI.
Germanium multiphase equation of state
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Crockett, Scott D.; Lorenzi-Venneri, Giulia De; Kress, Joel D.; Rudin, Sven P.
2014-05-07
A new SESAME multiphase germanium equation of state (EOS) has been developed using the best available experimental data and density functional theory (DFT) calculations. The equilibrium EOS includes the Ge I (diamond), the Ge II (β-Sn) and the liquid phases. The foundation of the EOS is based on density functional theory calculations which are used to determine the cold curve and the Debye temperature. Results are compared to Hugoniot data through the solid-solid and solid-liquid transitions. We propose some experiments to better understand the dynamics of this element
Universal equation for Efimov states
Braaten, Eric; Hammer, H.-W.; Kusunoki, M.
2003-02-01
Efimov states are a sequence of shallow three-body bound states that arise when the two-body scattering length is large. Efimov showed that the binding energies of these states can be calculated in terms of the scattering length and a three-body parameter by solving a transcendental equation involving a universal function of one variable. We calculate this universal function using effective field theory and use it to describe the three-body system of {sup 4}He atoms. We also extend Efimov's theory to include the effects of deep two-body bound states, which give widths to the Efimov states.
Percent of Industrial Natural Gas Deliveries in New Mexico Represented...
U.S. Energy Information Administration (EIA) Indexed Site
Mexico Represented by the Price (Percent) Percent of Industrial Natural Gas Deliveries in New Mexico Represented by the Price (Percent) Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct ...
FACILITY REPRESENTATIVE PROGRAM STATUS, 6/21/1999
Broader source: Energy.gov [DOE]
Since September, 1993, the Office of Field Management has served as the Department’s corporate advocate for the Facility Representative Program. The Facility Representative (FR) is a critical...
1999 FACILITY REPRESENTATIVE CONFERENCE June 21 – 25, 1999
Broader source: Energy.gov [DOE]
The Department of Energy will host the Facility Representative Annual Meeting on June 21-25, 1999 at the Alexis Park Hotel in Las Vegas, Nevada. The meeting will give Facility Representatives and...
Facility Representative of the Year Award | Department of Energy
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Facility Representative of the Year Award Facility Representative of the Year Award The Facility Representative Award Program is a special award designed to recognize superior or exemplary service by a Facility Representative over a period of one year. This special award program has been established in accordance with the requirements of Department of Energy (DOE) Order 331.1C, Employee Performance Management and Recognition Program. PDF icon FROTY_Guidance_14-11-13.pdf Responsible Contacts
Josh Allen of Richland Operations Office Named 2014 Facility Representative
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
of the Year | Department of Energy Josh Allen of Richland Operations Office Named 2014 Facility Representative of the Year Josh Allen of Richland Operations Office Named 2014 Facility Representative of the Year May 21, 2015 - 1:22pm Addthis Josh Allen of Richland Operations Office Named 2014 Facility Representative of the Year About 200 Department of Energy (DOE) federal employees are Facility Representatives (FR) who provide day-to-day oversight of contractor operations at DOE facilities.
1Q CY2000 (PDF), Facility Representative Program Performance Indicators
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Quarterly Report | Department of Energy 1Q CY2000 (PDF), Facility Representative Program Performance Indicators Quarterly Report 1Q CY2000 (PDF), Facility Representative Program Performance Indicators Quarterly Report "The Facility Representative Program Performance Indicators (PIs) Quarterly Report is attached, covering the period from January 2000 to March 2000. Data for these indicators are gathered by the Field elements quarterly per the Facility Representatives Standard, DOE-STD-1
4Q CY2000 (PDF), Facility Representative Program Performance Indicators
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Quarterly Report | Department of Energy 4Q CY2000 (PDF), Facility Representative Program Performance Indicators Quarterly Report 4Q CY2000 (PDF), Facility Representative Program Performance Indicators Quarterly Report "The Facility Representative Program Performance Indicators Quarterly Report is attached, covering the period from October to December 2000. Data for these indicators are gathered by the Field elements quarterly per the Facility Representatives Standard, 063, and reported
The equation of state of nuclear matter
Gandolfi, Stefano; Carlson, Joseph Allen
2015-06-30
A brief status report of research on equation of state (EOS) of nuclear matter is provided, along with two graphs.
Product equation of state for polysulfone
Ticknor, Christopher
2015-09-30
Here we review the new polysulfone product equation of state (EOS) made with magpie, a chemical equilibrium code.
Equation determines pressure drop in coiled tubing
Yang, Y.S.
1995-12-04
A single equation can determine the pressure drop in wells with laminar, transitional, and turbulent incompressible fluid flow in coiled tubing or other steel tubulars. The single equation is useful, especially in computer-aided design and operations. The equation is derived and illustrated by an example.
Boundary conditions for the subdiffusion equation
Shkilev, V. P.
2013-04-15
The boundary conditions for the subdiffusion equations are formulated using the continuous-time random walk model, as well as several versions of the random walk model on an irregular lattice. It is shown that the boundary conditions for the same equation in different models have different forms, and this difference considerably affects the solutions of this equation.
Boltzmann equation solver adapted to emergent chemical non-equilibrium
Birrell, Jeremiah; Wilkening, Jon; Rafelski, Johann
2015-01-15
We present a novel method to solve the spatially homogeneous and isotropic relativistic Boltzmann equation. We employ a basis set of orthogonal polynomials dynamically adapted to allow for emergence of chemical non-equilibrium. Two time dependent parameters characterize the set of orthogonal polynomials, the effective temperature T(t) and phase space occupation factor ?(t). In this first paper we address (effectively) massless fermions and derive dynamical equations for T(t) and ?(t) such that the zeroth order term of the basis alone captures the particle number density and energy density of each particle distribution. We validate our method and illustrate the reduced computational cost and the ability to easily represent final state chemical non-equilibrium by studying a model problem that is motivated by the physics of the neutrino freeze-out processes in the early Universe, where the essential physical characteristics include reheating from another disappearing particle component (e{sup }-annihilation)
Real-time and imaginary-time quantum hierarchal Fokker-Planck equations
Office of Scientific and Technical Information (OSTI)
(Journal Article) | SciTech Connect Real-time and imaginary-time quantum hierarchal Fokker-Planck equations Citation Details In-Document Search Title: Real-time and imaginary-time quantum hierarchal Fokker-Planck equations We consider a quantum mechanical system represented in phase space (referred to hereafter as "Wigner space"), coupled to a harmonic oscillator bath. We derive quantum hierarchal Fokker-Planck (QHFP) equations not only in real time but also in imaginary time,
CNS represented at inaugural Energetics Consortium | Y-12 National Security
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Complex CNS represented at ... CNS represented at inaugural Energetics Consortium Posted: February 16, 2016 - 6:53pm CNS was well represented at the first National Energetic Materials Consortium. About 70 university researchers and government and industry experts from across the country, including Consolidated Nuclear Security employees, joined forces at the first ever National Energetic Materials Consortium hosted by Texas Tech University. Pantex's Christopher Young said, "There are a
Facility Representative, Technical Area (TA-55) Plutonium Facility, Los
National Nuclear Security Administration (NNSA)
Alamos Site Office | National Nuclear Security Administration Facility Representative, Technical Area (TA-55) Plutonium Facility, Los Alamos Site Office John Krepps John Krepps June 2010 U.S. Department of Energy Facility Representative of the Year John Krepps, a facility representative for the National Nuclear Security Administration's (NNSA) Los Alamos Site Office, received the Department of Energy's top award for oversight of nuclear and non-nuclear facilities. Krepps, a Los Alamos
The Representative Concentration Pathways: An Overview (Journal Article) |
Office of Scientific and Technical Information (OSTI)
SciTech Connect The Representative Concentration Pathways: An Overview Citation Details In-Document Search Title: The Representative Concentration Pathways: An Overview This paper summarizes the development process and main characteristics of the Representative Concentration Pathways (RCPs), a set of four new scenarios developed for the climate modeling community as a basis for long-term and near-term modeling experiments. The four RCPs together span the range of year 2100 radiative forcing
Dr. Kelli Joseph, NYISO Representing the ISO-RTO Council
Broader source: Energy.gov (indexed) [DOE]
Kelli Joseph, NYISO Representing the ISO-RTO Council July 28, 2014 DOE Quadrennial Energy Review Gas Electric Interdependencies: Coordination Efforts, Regional Issues, and...
Herbert Richardson: Before The U.S. House of Representatives...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Herbert Richardson: Before The U.S. House of Representatives Committee on Energy and Commerce Subcommittee on Oversight and Investigations Herbert Richardson: Before The U.S. House ...
Appointment of Contracting Officers and Contracting Officer Representatives
Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]
2004-04-21
The Order established procedures governing the selection, appointment and termination of Department of Energy contracting officers and contracting officer representatives. Supersedes DOE O 541.1A.
Double distributions and evolution equations
A.V. Radyushkin
1998-05-01
Applications of perturbative QCD to deeply virtual Compton scattering and hard exclusive meson electroproduction processes require a generalization of usual parton distributions for the case when long-distance information is accumulated in nonforward matrix elements < p{prime} {vert_bar}O(0,z){vert_bar}p > of quark and gluon light-cone operators. In their previous papers the authors used two types of nonperturbative functions parameterizing such matrix elements: double distributions F(x,y;t) and nonforward distribution functions F{sub {zeta}}(X;t). Here they discuss in more detail the double distributions (DD's) and evolution equations which they satisfy. They propose simple models for F(x,y;t=0) DD's with correct spectral and symmetry properties which also satisfy the reduction relations connecting them to the usual parton densities f(x). In this way, they obtain self-consistent models for the {zeta}-dependence of nonforward distributions. They show that, for small {zeta}, one can easily obtain nonforward distributions (in the X > {zeta} region) from the parton densities: F{sub {zeta}} (X;t=0) {approx} f(X{minus}{zeta}/2).
Scalable Equation of State Capability
Epperly, T W; Fritsch, F N; Norquist, P D; Sanford, L A
2007-12-03
The purpose of this techbase project was to investigate the use of parallel array data types to reduce the memory footprint of the Livermore Equation Of State (LEOS) library. Addressing the memory scalability of LEOS is necessary to run large scientific simulations on IBM BG/L and future architectures with low memory per processing core. We considered using normal MPI, one-sided MPI, and Global Arrays to manage the distributed array and ended up choosing Global Arrays because it was the only communication library that provided the level of asynchronous access required. To reduce the runtime overhead using a parallel array data structure, a least recently used (LRU) caching algorithm was used to provide a local cache of commonly used parts of the parallel array. The approach was initially implemented in a isolated copy of LEOS and was later integrated into the main trunk of the LEOS Subversion repository. The approach was tested using a simple test. Testing indicated that the approach was feasible, and the simple LRU caching had a 86% hit rate.
Darboux transformation for the NLS equation
Aktosun, Tuncay; Mee, Cornelis van der
2010-03-08
We analyze a certain class of integral equations associated with Marchenko equations and Gel'fand-Levitan equations. Such integral equations arise through a Fourier transformation on various ordinary differential equations involving a spectral parameter. When the integral operator is perturbed by a finite-rank perturbation, we explicitly evaluate the change in the solution in terms of the unperturbed quantities and the finite-rank perturbation. We show that this result provides a fundamental approach to derive Darboux transformations for various systems of ordinary differential operators. We illustrate our theory by providing the explicit Darboux transformation for the Zakharov-Shabat system and show how the potential and wave function change when a simple discrete eigenvalue is added to the spectrum, and thus we also provide a one-parameter family of Darboux transformations for the nonlinear Schroedinger equation.
The Boltzmann equation in the difference formulation
Szoke, Abraham; Brooks III, Eugene D.
2015-05-06
First we recall the assumptions that are needed for the validity of the Boltzmann equation and for the validity of the compressible Euler equations. We then present the difference formulation of these equations and make a connection with the time-honored Chapman - Enskog expansion. We discuss the hydrodynamic limit and calculate the thermal conductivity of a monatomic gas, using a simplified approximation for the collision term. Our formulation is more consistent and simpler than the traditional derivation.
Microsoft PowerPoint - neely2004session3
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
* Map physical space to logical rectangular coordinates * Solve inverse Laplace equation Equipotential Relaxation Equipotential Relaxation x y Logical space Physical...
The generalized SchrdingerLangevin equation
Bargueo, Pedro; Miret-Arts, Salvador
2014-07-15
In this work, for a Brownian particle interacting with a heat bath, we derive a generalization of the so-called SchrdingerLangevin or Kostin equation. This generalization is based on a nonlinear interaction model providing a state-dependent dissipation process exhibiting multiplicative noise. Two straightforward applications to the measurement process are then analyzed, continuous and weak measurements in terms of the quantum Bohmian trajectory formalism. Finally, it is also shown that the generalized uncertainty principle, which appears in some approaches to quantum gravity, can be expressed in terms of this generalized equation. -- Highlights: We generalize the Kostin equation for arbitrary systembath coupling. This generalization is developed both in the Schrdinger and Bohmian formalisms. We write the generalized Kostin equation for two measurement problems. We reformulate the generalized uncertainty principle in terms of this equation.
Changes to the Facility Representative Program, 10/26/1999
Broader source: Energy.gov [DOE]
Effective October 1, 1999, the Deputy Secretary tasked this office to manage the Facility Representative Program. We look forward to working with you in continuing and improving this very important...
Appointment of Contracting Officers and Contracting Officer Representatives
Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]
1996-04-30
To establish procedures governing the selection, appointment, and termination of contracting officers and for the appointment of contracting officer representatives. Cancels DOE Order 4200.4A. Canceled by DOE O 541.1A.
Department of Defense Representatives Visit Hanford to Benchmark Safety
Broader source: Energy.gov [DOE]
RICHLAND, Wash., December 16, 2005, Representatives of the Department of Defense's (DoD's) Voluntary Protection Program Center of Excellence (VPP CX) working to reduce injuries at selected (DoD)...
DOE Representative to World Institute of Nuclear Safety (WINS) | National
National Nuclear Security Administration (NNSA)
Nuclear Security Administration DOE Representative to World Institute of Nuclear Safety (WINS) Lisa G. Hilliard Lisa Hilliard August 2009 NNSA Administrator's Silver Award Lisa G. Hilliard has received the NNSA Administrator's Silver Award for her sustained distinguished accomplishments as the Office Director of the DOE office to the U.S. Mission to International Organizations in Vienna from May 1993 to April 2009, serving four Ambassadors, two interim Representatives, and six Secretaries of
Statistically designed study of the variables and parameters of carbon dioxide equations of state
Donohue, M.D.; Naiman, D.Q.; Jin, Gang; Loehe, J.R.
1991-05-01
Carbon dioxide is used widely in enhanced oil recovery (EOR) processes to maximize the production of crude oil from aging and nearly depleted oil wells. Carbon dioxide also is encountered in many processes related to oil recovery. Accurate representations of the properties of carbon dioxide, and its mixtures with hydrocarbons, play a critical role in a number of enhanced oil recovery operations. One of the first tasks of this project was to select an equation of state to calculate the properties of carbon dioxide and its mixtures. The equations simplicity, accuracy, and reliability in representing phase behavior and thermodynamic properties of mixtures containing carbon dioxide with hydrocarbons at conditions relevant to enhanced oil recovery were taken into account. We also have determined the thermodynamic properties that are important to enhanced oil recovery and the ranges of temperature, pressure and composition that are important. We chose twelve equations of state for preliminary studies to be evaluated against these criteria. All of these equations were tested for pure carbon dioxide and eleven were tested for pure alkanes and their mixtures with carbon dioxide. Two equations, the ALS equation and the ESD equation, were selected for detailed statistical analysis. 54 refs., 41 figs., 36 tabs.
Fokker-Planck equation in mirror research
Post, R.F.
1983-08-11
Open confinement systems based on the magnetic mirror principle depend on the maintenance of particle distributions that may deviate substantially from Maxwellian distributions. Mirror research has therefore from the beginning relied on theoretical predictions of non-equilibrium rate processes obtained from solutions to the Fokker-Planck equation. The F-P equation plays three roles: Design of experiments, creation of classical standards against which to compare experiment, and predictions concerning mirror based fusion power systems. Analytical and computational approaches to solving the F-P equation for mirror systems will be reviewed, together with results and examples that apply to specific mirror systems, such as the tandem mirror.
Representing the thermal state in time-dependent density functional theory
Modine, N. A.; Hatcher, R. M.
2015-05-28
Classical molecular dynamics (MD) provides a powerful and widely used approach to determining thermodynamic properties by integrating the classical equations of motion of a system of atoms. Time-Dependent Density Functional Theory (TDDFT) provides a powerful and increasingly useful approach to integrating the quantum equations of motion for a system of electrons. TDDFT efficiently captures the unitary evolution of a many-electron state by mapping the system into a fictitious non-interacting system. In analogy to MD, one could imagine obtaining the thermodynamic properties of an electronic system from a TDDFT simulation in which the electrons are excited from their ground state by a time-dependent potential and then allowed to evolve freely in time while statistical data are captured from periodic snapshots of the system. For a variety of systems (e.g., many metals), the electrons reach an effective state of internal equilibrium due to electron-electron interactions on a time scale that is short compared to electron-phonon equilibration. During the initial time-evolution of such systems following electronic excitation, electron-phonon interactions should be negligible, and therefore, TDDFT should successfully capture the internal thermalization of the electrons. However, it is unclear how TDDFT represents the resulting thermal state. In particular, the thermal state is usually represented in quantum statistical mechanics as a mixed state, while the occupations of the TDDFT wavefunctions are fixed by the initial state in TDDFT. We work to address this puzzle by (A) reformulating quantum statistical mechanics so that thermodynamic expectations can be obtained as an unweighted average over a set of many-body pure states and (B) constructing a family of non-interacting (single determinant) TDDFT states that approximate the required many-body states for the canonical ensemble.
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Maddalena, Damian; Hoffman, Forrest; Kumar, Jitendra; Hargrove, William
2014-08-01
Sampling networks rarely conform to spatial and temporal ideals, often comprised of network sampling points which are unevenly distributed and located in less than ideal locations due to access constraints, budget limitations, or political conflict. Quantifying the global, regional, and temporal representativeness of these networks by quantifying the coverage of network infrastructure highlights the capabilities and limitations of the data collected, facilitates upscaling and downscaling for modeling purposes, and improves the planning efforts for future infrastructure investment under current conditions and future modeled scenarios. The work presented here utilizes multivariate spatiotemporal clustering analysis and representativeness analysis for quantitative landscape characterization and assessment of the Fluxnet, RAINFOR, and ForestGEO networks. Results include ecoregions that highlight patterns of bioclimatic, topographic, and edaphic variables and quantitative representativeness maps of individual and combined networks.
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Maddalena, Damian; Hoffman, Forrest; Kumar, Jitendra; Hargrove, William
Sampling networks rarely conform to spatial and temporal ideals, often comprised of network sampling points which are unevenly distributed and located in less than ideal locations due to access constraints, budget limitations, or political conflict. Quantifying the global, regional, and temporal representativeness of these networks by quantifying the coverage of network infrastructure highlights the capabilities and limitations of the data collected, facilitates upscaling and downscaling for modeling purposes, and improves the planning efforts for future infrastructure investment under current conditions and future modeled scenarios. The work presented here utilizes multivariate spatiotemporal clustering analysis and representativeness analysis for quantitative landscape characterization and assessment of the Fluxnet, RAINFOR, and ForestGEO networks. Results include ecoregions that highlight patterns of bioclimatic, topographic, and edaphic variables and quantitative representativeness maps of individual and combined networks.
Equator Appliance: ENERGY STAR Referral (EZ 3720)
Broader source: Energy.gov [DOE]
DOE referred Equator Appliance clothes washer EZ 3720 to EPA, brand manager of the ENERGY STAR program, for appropriate action after DOE testing revealed that the model does not meet ENERGY STAR requirements.
Coherency Does Not Equate to Stability
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
for Coherency Does Not Equate to Stability LLNL BES Programs Highlight Coherency Does Not Equate to Stability As-grown nanotwin (NT) copper (A) SEM image. (B) An edge-on inverse pole figure orientation mapping (IPFOM) image, the coherent and incoherent twin boundaries are labeled as CTB and ITB (inside circles), respectively. (C) A high-resolution IPFOM image of CTBs. Some ITB segments are marked with white arrows. (D) An IPFOM image of along columnar grain boundary showing numerous ITB segments
WIPP Representative Selected For National Environmental Justice Advisory Board
Broader source: Energy.gov [DOE]
CARLSBAD, N.M. – Organizers say no similar opportunity or conference exists in America. In April, representatives from federal and state agencies, local governments, tribes, communities, business, academia and other groups will gather in Washington, D.C. for the 2012 National Environmental Justice Conference and Training Program.
Appointment of Contracting Officers and Contracting Officer's Representatives
Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]
2000-10-27
To establish procedures governing the selection, appointment, and termination of contracting officers and for the appointment of contracting officer's representatives. To ensure that only trained and qualified procurement and financial assistance professionals, within the scope of this Order, serve as contracting officers. Cancels DOE O 541.1. Canceled by DOE O 541.1B.
Pierantozzi, T.; Vazquez, L.
2005-11-01
Through fractional calculus and following the method used by Dirac to obtain his well-known equation from the Klein-Gordon equation, we analyze a possible interpolation between the Dirac and the diffusion equations in one space dimension. We study the transition between the hyperbolic and parabolic behaviors by means of the generalization of the D'Alembert formula for the classical wave equation and the invariance under space and time inversions of the interpolating fractional evolution equations Dirac like. Such invariance depends on the values of the fractional index and is related to the nonlocal property of the time fractional differential operator. For this system of fractional evolution equations, we also find an associated conserved quantity analogous to the Hamiltonian for the classical Dirac case.
An analysis of representative heating load lines for residential HSPF ratings
Rice, C. Keith; Shen, Bo; Shrestha, Som S.
2015-07-01
This report describes an analysis to investigate representative heating loads for single-family detached homes using current EnergyPlus simulations (DOE 2014a). Hourly delivered load results are used to determine binned load lines using US Department of Energy (DOE) residential prototype building models (DOE 2014b) developed by Pacific Northwest National Laboratory (PNNL). The selected residential single-family prototype buildings are based on the 2006 International Energy Conservation Code (IECC 2006) in the DOE climate regions. The resulting load lines are compared with the American National Standards Institute (ANSI)/Air-Conditioning, Heating, and Refrigeration Institute (AHRI) Standard 210/240 (AHRI 2008) minimum and maximum design heating requirement (DHR) load lines of the heating seasonal performance factor (HSPF) ratings procedure for each region. The results indicate that a heating load line closer to the maximum DHR load line, and with a lower zero load ambient temperature, is more representative of heating loads predicted for EnergyPlus prototype residential buildings than the minimum DHR load line presently used to determine HSPF ratings. An alternative heating load line equation was developed and compared to binned load lines obtained from the EnergyPlus simulation results. The effect on HSPF of the alternative heating load line was evaluated for single-speed and two-capacity heat pumps, and an average HSPF reduction of 16% was found. The alternative heating load line relationship is tied to the rated cooling capacity of the heat pump based on EnergyPlus autosizing, which is more representative of the house load characteristics than the rated heating capacity. The alternative heating load line equation was found to be independent of climate for the six DOE climate regions investigated, provided an adjustable zero load ambient temperature is used. For Region IV, the default DOE climate region used for HSPF ratings, the higher load line results in an ~28% increase in delivered heating load and an ~52% increase in the estimated heating operating cost over that given in the AHRI directory (AHRI 2014).
Processes, data structures, and apparatuses for representing knowledge
Hohimer, Ryan E.; Thomson, Judi R.; Harvey, William J.; Paulson, Patrick R.; Whiting, Mark A.; Tratz, Stephen C.; Chappell, Alan R.; Butner, R. Scott
2011-09-20
Processes, data structures, and apparatuses to represent knowledge are disclosed. The processes can comprise labeling elements in a knowledge signature according to concepts in an ontology and populating the elements with confidence values. The data structures can comprise knowledge signatures stored on computer-readable media. The knowledge signatures comprise a matrix structure having elements labeled according to concepts in an ontology, wherein the value of the element represents a confidence that the concept is present in an information space. The apparatus can comprise a knowledge representation unit having at least one ontology stored on a computer-readable medium, at least one data-receiving device, and a processor configured to generate knowledge signatures by comparing datasets obtained by the data-receiving devices to the ontologies.
Gamba, Irene M.; Haack, Jeffrey R.
2014-08-01
We present the formulation of a conservative spectral method for the Boltzmann collision operator with anisotropic scattering cross-sections. The method is an extension of the conservative spectral method of Gamba and Tharkabhushanam [17,18], which uses the weak form of the collision operator to represent the collisional term as a weighted convolution in Fourier space. The method is tested by computing the collision operator with a suitably cut-off angular cross section and comparing the results with the solution of the Landau equation. We analytically study the convergence rate of the Fourier transformed Boltzmann collision operator in the grazing collisions limit to the Fourier transformed Landau collision operator under the assumption of some regularity and decay conditions of the solution to the Boltzmann equation. Our results show that the angular singularity which corresponds to the Rutherford scattering cross section is the critical singularity for which a grazing collision limit exists for the Boltzmann operator. Additionally, we numerically study the differences between homogeneous solutions of the Boltzmann equation with the Rutherford scattering cross section and an artificial cross section, which give convergence to solutions of the Landau equation at different asymptotic rates. We numerically show the rate of the approximation as well as the consequences for the rate of entropy decay for homogeneous solutions of the Boltzmann equation and Landau equation.
U.S. Representative Frank Lucas and Oklahoma State Senator
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
3 U.S. Representative Frank Lucas and Oklahoma State Senator David Myers recently voiced support for the ARM Program SGP site in an effort to highlight the site and its needs. Though the SGP central facility and activity hub near Lamont, Oklahoma, has 31 employees and attracts hundreds of visiting scientists, its only access is via dirt roads. These roads can make travel to the site, especially in wet weather, difficult and treacherous for employees, visitors, and heavy vehicles delivering
Equation of State from Lattice QCD Calculations (Conference)...
Office of Scientific and Technical Information (OSTI)
Conference: Equation of State from Lattice QCD Calculations Citation Details In-Document Search Title: Equation of State from Lattice QCD Calculations You are accessing a...
An Acoustic Wave Equation for Tilted Transversely Isotropic Media...
Office of Scientific and Technical Information (OSTI)
An Acoustic Wave Equation for Tilted Transversely Isotropic Media Citation Details In-Document Search Title: An Acoustic Wave Equation for Tilted Transversely Isotropic Media ...
Solving the power flow equations: a monotone operator approach...
Office of Scientific and Technical Information (OSTI)
Technical Report: Solving the power flow equations: a monotone operator approach Citation Details In-Document Search Title: Solving the power flow equations: a monotone operator ...
Equation of State Measurements by Radiography Provide Evidence...
Office of Scientific and Technical Information (OSTI)
Equation of State Measurements by Radiography Provide Evidence for a Liquid-Liquid Phase Transition in Cerium Citation Details In-Document Search Title: Equation of State ...
Nonparametric reconstruction of the dark energy equation of state...
Office of Scientific and Technical Information (OSTI)
energy equation of state from diverse data sets Citation Details In-Document Search Title: Nonparametric reconstruction of the dark energy equation of state from diverse data ...
Single-point representative sampling with shrouded probes
McFarland, A.R.; Rodgers, J.C.
1993-08-01
The Environmental Protection Agency (EPA) prescribed methodologies for sampling radionuclides in air effluents from stacks and ducts at US Department of Energy (DOE) facilities. Requirements include use of EPA Method 1 for the location of sampling sites and use of American National Standards Institute (ANSI) N13.1 for guidance in design of sampling probes and the number of probes at a given site. Application of ANSI N13.1 results in sampling being performed with multiprobe rakes that have as many as 20 probes. There can be substantial losses of aerosol particles in such sampling that will degrade the quality of emission estimates from a nuclear facility. Three alternate methods, technically justified herein, are proposed for effluent sampling. First, a shrouded aerosol sampling probe should replace the sharp-edged elbowed-nozzle recommended by ANSI. This would reduce the losses of aerosol particles in probes and result in the acquisition of more representative aerosol samples. Second, the rakes of multiple probes that are intended to acquire representative samples through spatial coverage should be replaced by a single probe located where contaminant mass and fluid momentum are both well mixed. A representative sample can be obtained from a well-mixed flow. Some effluent flows will need to be engineered to achieve acceptable mixing. Third, sample extraction should be performed at a constant flow rate through a suitable designed shrouded probe rather than at a variable flow rate through isokinetic probes. A shrouded probe is shown to have constant sampling characteristics over a broad range of stack velocities when operated at a fixed flow rate.
Solves the Multigroup Neutron Diffusion Equation
Energy Science and Technology Software Center (OSTI)
1995-06-23
GNOMER is a program which solves the multigroup neutron diffusion equation in 1D, 2D and 3D cartesian geometry. The program is designed to calculate the global core power distributions (with thermohydraulic feedbacks), as well as power distribution and homogenized cross sections over a fuel assembly.
Representing the thermal state in time-dependent density functional theory
Modine, N. A.; Hatcher, R. M.
2015-05-28
Classical molecular dynamics (MD) provides a powerful and widely used approach to determining thermodynamic properties by integrating the classical equations of motion of a system of atoms. Time-Dependent Density Functional Theory (TDDFT) provides a powerful and increasingly useful approach to integrating the quantum equations of motion for a system of electrons. TDDFT efficiently captures the unitary evolution of a many-electron state by mapping the system into a fictitious non-interacting system. In analogy to MD, one could imagine obtaining the thermodynamic properties of an electronic system from a TDDFT simulation in which the electrons are excited from their ground state by a time-dependent potential and then allowed to evolve freely in time while statistical data are captured from periodic snapshots of the system. For a variety of systems (e.g., many metals), the electrons reach an effective state of internal equilibrium due to electron-electron interactions on a time scale that is short compared to electron-phonon equilibration. During the initial time-evolution of such systems following electronic excitation, electron-phonon interactions should be negligible, and therefore, TDDFT should successfully capture the internal thermalization of the electrons. However, it is unclear how TDDFT represents the resulting thermal state. In particular, the thermal state is usually represented in quantum statistical mechanics as a mixed state, while the occupations of the TDDFT wave functions are fixed by the initial state in TDDFT. Two key questions involve (1) reformulating quantum statistical mechanics so that thermodynamic expectations can be obtained as an unweighted average over a set of many-body pure states and (2) constructing a family of non-interacting (single determinant) TDDFT states that approximate the required many-body states for the canonical ensemble. In Section II, we will address these questions by first demonstrating that thermodynamic expectations can be evaluated by averaging over certain many-body pure states, which we will call thermal states, and then constructing TDDFT states that approximate these thermal states. In Section III, we will present some numerical tests of the resulting theory, and in Section IV, we will summarize our main results and discuss some possible future directions for this work.
Representing the thermal state in time-dependent density functional theory
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Modine, N. A.; Hatcher, R. M.
2015-05-28
Classical molecular dynamics (MD) provides a powerful and widely used approach to determining thermodynamic properties by integrating the classical equations of motion of a system of atoms. Time-Dependent Density Functional Theory (TDDFT) provides a powerful and increasingly useful approach to integrating the quantum equations of motion for a system of electrons. TDDFT efficiently captures the unitary evolution of a many-electron state by mapping the system into a fictitious non-interacting system. In analogy to MD, one could imagine obtaining the thermodynamic properties of an electronic system from a TDDFT simulation in which the electrons are excited from their ground state bymore » a time-dependent potential and then allowed to evolve freely in time while statistical data are captured from periodic snapshots of the system. For a variety of systems (e.g., many metals), the electrons reach an effective state of internal equilibrium due to electron-electron interactions on a time scale that is short compared to electron-phonon equilibration. During the initial time-evolution of such systems following electronic excitation, electron-phonon interactions should be negligible, and therefore, TDDFT should successfully capture the internal thermalization of the electrons. However, it is unclear how TDDFT represents the resulting thermal state. In particular, the thermal state is usually represented in quantum statistical mechanics as a mixed state, while the occupations of the TDDFT wave functions are fixed by the initial state in TDDFT. Two key questions involve (1) reformulating quantum statistical mechanics so that thermodynamic expectations can be obtained as an unweighted average over a set of many-body pure states and (2) constructing a family of non-interacting (single determinant) TDDFT states that approximate the required many-body states for the canonical ensemble. In Section II, we will address these questions by first demonstrating that thermodynamic expectations can be evaluated by averaging over certain many-body pure states, which we will call thermal states, and then constructing TDDFT states that approximate these thermal states. In Section III, we will present some numerical tests of the resulting theory, and in Section IV, we will summarize our main results and discuss some possible future directions for this work.« less
Defining And Characterizing Sample Representativeness For DWPF Melter Feed Samples
Shine, E. P.; Poirier, M. R.
2013-10-29
Representative sampling is important throughout the Defense Waste Processing Facility (DWPF) process, and the demonstrated success of the DWPF process to achieve glass product quality over the past two decades is a direct result of the quality of information obtained from the process. The objective of this report was to present sampling methods that the Savannah River Site (SRS) used to qualify waste being dispositioned at the DWPF. The goal was to emphasize the methodology, not a list of outcomes from those studies. This methodology includes proven methods for taking representative samples, the use of controlled analytical methods, and data interpretation and reporting that considers the uncertainty of all error sources. Numerous sampling studies were conducted during the development of the DWPF process and still continue to be performed in order to evaluate options for process improvement. Study designs were based on use of statistical tools applicable to the determination of uncertainties associated with the data needs. Successful designs are apt to be repeated, so this report chose only to include prototypic case studies that typify the characteristics of frequently used designs. Case studies have been presented for studying in-tank homogeneity, evaluating the suitability of sampler systems, determining factors that affect mixing and sampling, comparing the final waste glass product chemical composition and durability to that of the glass pour stream sample and other samples from process vessels, and assessing the uniformity of the chemical composition in the waste glass product. Many of these studies efficiently addressed more than one of these areas of concern associated with demonstrating sample representativeness and provide examples of statistical tools in use for DWPF. The time when many of these designs were implemented was in an age when the sampling ideas of Pierre Gy were not as widespread as they are today. Nonetheless, the engineers and statisticians used carefully thought out designs that systematically and economically provided plans for data collection from the DWPF process. Key shared features of the sampling designs used at DWPF and the Gy sampling methodology were the specification of a standard for sample representativeness, an investigation that produced data from the process to study the sampling function, and a decision framework used to assess whether the specification was met based on the data. Without going into detail with regard to the seven errors identified by Pierre Gy, as excellent summaries are readily available such as Pitard [1989] and Smith [2001], SRS engineers understood, for example, that samplers can be biased (Gy�s extraction error), and developed plans to mitigate those biases. Experiments that compared installed samplers with more representative samples obtained directly from the tank may not have resulted in systematically partitioning sampling errors into the now well-known error categories of Gy, but did provide overall information on the suitability of sampling systems. Most of the designs in this report are related to the DWPF vessels, not the large SRS Tank Farm tanks. Samples from the DWPF Slurry Mix Evaporator (SME), which contains the feed to the DWPF melter, are characterized using standardized analytical methods with known uncertainty. The analytical error is combined with the established error from sampling and processing in DWPF to determine the melter feed composition. This composition is used with the known uncertainty of the models in the Product Composition Control System (PCCS) to ensure that the wasteform that is produced is comfortably within the acceptable processing and product performance region. Having the advantage of many years of processing that meets the waste glass product acceptance criteria, the DWPF process has provided a considerable amount of data about itself in addition to the data from many special studies. Demonstrating representative sampling directly from the large Tank Farm tanks is a difficult, if not unsolvable enterprise due to limited accessibility. However, the consistency and the adequacy of sampling and mixing at SRS could at least be studied under the controlled process conditions based on samples discussed by Ray and others [2012a] in Waste Form Qualification Report (WQR) Volume 2 and the transfers from Tanks 40H and 51H to the Sludge Receipt and Adjustment Tank (SRAT) within DWPF. It is important to realize that the need for sample representativeness becomes more stringent as the material gets closer to the melter, and the tanks within DWPF have been studied extensively to meet those needs.
The Korarchaeota: Archaeal orphans representing an ancestral lineage of life
Elkins, James G.; Kunin, Victor; Anderson, Iain; Barry, Kerrie; Goltsman, Eugene; Lapidus, Alla; Hedlund, Brian; Hugenholtz, Phil; Kyrpides, Nikos; Graham, David; Keller, Martin; Wanner, Gerhard; Richardson, Paul; Stetter, Karl O.
2007-05-01
Based on conserved cellular properties, all life on Earth can be grouped into different phyla which belong to the primary domains Bacteria, Archaea, and Eukarya. However, tracing back their evolutionary relationships has been impeded by horizontal gene transfer and gene loss. Within the Archaea, the kingdoms Crenarchaeota and Euryarchaeota exhibit a profound divergence. In order to elucidate the evolution of these two major kingdoms, representatives of more deeply diverged lineages would be required. Based on their environmental small subunit ribosomal (ss RNA) sequences, the Korarchaeota had been originally suggested to have an ancestral relationship to all known Archaea although this assessment has been refuted. Here we describe the cultivation and initial characterization of the first member of the Korarchaeota, highly unusual, ultrathin filamentous cells about 0.16 {micro}m in diameter. A complete genome sequence obtained from enrichment cultures revealed an unprecedented combination of signature genes which were thought to be characteristic of either the Crenarchaeota, Euryarchaeota, or Eukarya. Cell division appears to be mediated through a FtsZ-dependent mechanism which is highly conserved throughout the Bacteria and Euryarchaeota. An rpb8 subunit of the DNA-dependent RNA polymerase was identified which is absent from other Archaea and has been described as a eukaryotic signature gene. In addition, the representative organism possesses a ribosome structure typical for members of the Crenarchaeota. Based on its gene complement, this lineage likely diverged near the separation of the two major kingdoms of Archaea. Further investigations of these unique organisms may shed additional light onto the evolution of extant life.
Changing the Equation in STEM Education
Broader source: Energy.gov [DOE]
Editor's Note: This is a cross post of an announcement that the White House featured on its blog last week. Check out the video below for Secretary Chu's thoughts on how an education in math and science helps students understand the world and deal with the pressing issues of our time. Today, President Obama announced the launch of Change the Equation, a CEO-led effort to dramatically improve education in science, technology, engineering, and math (STEM), as part of his “Educate to Innovate” campaign. Change the Equation is a non-profit organization dedicated to mobilizing the business community to improve the quality of STEM education in the United States.
The quasicontinuum Fokker-Plank equation
Alexander, Francis J
2008-01-01
We present a regularized Fokker-Planck equation with more accurate short-time and high-frequency behavior for continuous-time, discrete-state systems. The regularization preserves crucial aspects of state-space discreteness lost in the standard Kramers-Moyal expansion. We apply the method to a simple example of biochemical reaction kinetics and to a two-dimensional symmetric random walk, and suggest its application to more complex systerns.
Development of surface mine cost estimating equations
Not Available
1980-09-26
Cost estimating equations were developed to determine capital and operating costs for five surface coal mine models in Central Appalachia, Northern Appalachia, Mid-West, Far-West, and Campbell County, Wyoming. Engineering equations were used to estimate equipment costs for the stripping function and for the coal loading and hauling function for the base case mine and for several mines with different annual production levels and/or different overburden removal requirements. Deferred costs were then determined through application of the base case depreciation schedules, and direct labor costs were easily established once the equipment quantities (and, hence, manpower requirements) were determined. The data points were then fit with appropriate functional forms, and these were then multiplied by appropriate adjustment factors so that the resulting equations yielded the model mine costs for initial and deferred capital and annual operating cost. (The validity of this scaling process is based on the assumption that total initial and deferred capital costs are proportional to the initial and deferred costs for the primary equipment types that were considered and that annual operating cost is proportional to the direct labor costs that were determined based on primary equipment quantities.) Initial capital costs ranged from $3,910,470 in Central Appalachia to $49,296,785; deferred capital costs ranged from $3,220,000 in Central Appalachia to $30,735,000 in Campbell County, Wyoming; and annual operating costs ranged from $2,924,148 in Central Appalachia to $32,708,591 in Campbell County, Wyoming. (DMC)
Simulating a Nationally Representative Housing Sample Using EnergyPlus
Hopkins, Asa S.; Lekov, Alex; Lutz, James; Rosenquist, Gregory; Gu, Lixing
2011-03-04
This report presents a new simulation tool under development at Lawrence Berkeley National Laboratory (LBNL). This tool uses EnergyPlus to simulate each single-family home in the Residential Energy Consumption Survey (RECS), and generates a calibrated, nationally representative set of simulated homes whose energy use is statistically indistinguishable from the energy use of the single-family homes in the RECS sample. This research builds upon earlier work by Ritchard et al. for the Gas Research Institute and Huang et al. for LBNL. A representative national sample allows us to evaluate the variance in energy use between individual homes, regions, or other subsamples; using this tool, we can also evaluate how that variance affects the impacts of potential policies. The RECS contains information regarding the construction and location of each sampled home, as well as its appliances and other energy-using equipment. We combined this data with the home simulation prototypes developed by Huang et al. to simulate homes that match the RECS sample wherever possible. Where data was not available, we used distributions, calibrated using the RECS energy use data. Each home was assigned a best-fit location for the purposes of weather and some construction characteristics. RECS provides some detail on the type and age of heating, ventilation, and air-conditioning (HVAC) equipment in each home; we developed EnergyPlus models capable of reproducing the variety of technologies and efficiencies represented in the national sample. This includes electric, gas, and oil furnaces, central and window air conditioners, central heat pumps, and baseboard heaters. We also developed a model of duct system performance, based on in-home measurements, and integrated this with fan performance to capture the energy use of single- and variable-speed furnace fans, as well as the interaction of duct and fan performance with the efficiency of heating and cooling equipment. Comparison with RECS revealed that EnergyPlus did not capture the heating-side behavior of heat pumps particularly accurately, and that our simple oil furnace and boiler models needed significant recalibration to fit with RECS. Simulating the full RECS sample on a single computer would take many hours, so we used the 'cloud computing' services provided by Amazon.com to simulate dozens of homes at once. This enabled us to simulate the full RECS sample, including multiple versions of each home to evaluate the impact of marginal changes, in less than 3 hours. Once the tool was calibrated, we were able to address several policy questions. We made a simple measurement of the heat replacement effect and showed that the net effect of heat replacement on primary energy use is likely to be less than 5%, relative to appliance-only measures of energy savings. Fuel switching could be significant, however. We also evaluated the national and regional impacts of a variety of 'overnight' changes in building characteristics or occupant behavior, including lighting, home insulation and sealing, HVAC system efficiency, and thermostat settings. For example, our model shows that the combination of increased home insulation and better sealed building shells could reduce residential natural gas use by 34.5% and electricity use by 6.5%, and a 1 degree rise in summer thermostat settings could save 2.1% of home electricity use. These results vary by region, and we present results for each U.S. Census division. We conclude by offering proposals for future work to improve the tool. Some proposed future work includes: comparing the simulated energy use data with the monthly RECS bill data; better capturing the variation in behavior between households, especially as it relates to occupancy and schedules; improving the characterization of recent construction and its regional variation; and extending the general framework of this simulation tool to capture multifamily housing units, such as apartment buildings.
Wave propagation in equivalent continuums representing truss lattice materials
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Messner, Mark C.; Barham, Matthew I.; Kumar, Mukul; Barton, Nathan R.
2015-07-29
Stiffness scales linearly with density in stretch-dominated lattice meta-materials offering the possibility of very light yet very stiff structures. Current additive manufacturing techniques can assemble structures consisting of these lattice materials, but the design of such structures will require accurate, efficient simulation techniques. Equivalent continuum models have several advantages over discrete truss models of stretch dominated lattices, including computational efficiency and ease of model construction. However, the development an equivalent model suitable for representing the dynamic response of a periodic truss is complicated by microinertial effects. This paper derives a dynamic equivalent continuum model for periodic truss structures and verifiesmore » it against detailed finite element simulations. The model must incorporate microinertial effects to accurately reproduce long-wavelength characteristics of the response such as anisotropic elastic soundspeeds. The formulation presented here also improves upon previous work by preserving equilibrium at truss joints for affine lattice deformation and by improving numerical stability by eliminating vertices in the effective yield surface.« less
Solving the Schroedinger equation using Smolyak interpolants
Avila, Gustavo; Carrington, Tucker Jr.
2013-10-07
In this paper, we present a new collocation method for solving the Schroedinger equation. Collocation has the advantage that it obviates integrals. All previous collocation methods have, however, the crucial disadvantage that they require solving a generalized eigenvalue problem. By combining Lagrange-like functions with a Smolyak interpolant, we device a collocation method that does not require solving a generalized eigenvalue problem. We exploit the structure of the grid to develop an efficient algorithm for evaluating the matrix-vector products required to compute energy levels and wavefunctions. Energies systematically converge as the number of points and basis functions are increased.
Sandia Equation of State Model Library
Energy Science and Technology Software Center (OSTI)
2013-08-29
The software provides a general interface for querying thermodynamic states of material models along with implementation of both general and specific equation of state models. In particular, models are provided for the IAPWS-IF97 and IAPWS95 water standards as well as the associated water standards for viscosity, thermal conductivity, and surface tension. The interface supports implementation of models in a variety of independent variable spaces. Also, model support routines are included that allow for coupling ofmore » models and determination and representation of phase boundaries.« less
Canonical equations of ideal magnetic hydrodynamics
Gorskii, V.B.
1987-07-01
Ideal magnetohydrodynamics is used to consider a general class of adiabatic flow in magnetic liquids. Two invariants of the canonical equations of motion--Hamiltonian and Lagrangian--are determined in terms of the canonical variables by using the approximate variational formulations. The resulting model describes adiabatic three-dimensional flow of a nonviscous compressible liquid with ideal electric conductivity and zero heat conductivity. A Clebsch transformation is used to arrive at a form of the Lagrange-Cauchy integral for a vortex flow.
Propagation of ultra-short solitons in stochastic Maxwell's equations
Kurt, Levent; Schfer, Tobias
2014-01-15
We study the propagation of ultra-short short solitons in a cubic nonlinear medium modeled by nonlinear Maxwell's equations with stochastic variations of media. We consider three cases: variations of (a) the dispersion, (b) the phase velocity, (c) the nonlinear coefficient. Using a modified multi-scale expansion for stochastic systems, we derive new stochastic generalizations of the short pulse equation that approximate the solutions of stochastic nonlinear Maxwell's equations. Numerical simulations show that soliton solutions of the short pulse equation propagate stably in stochastic nonlinear Maxwell's equations and that the generalized stochastic short pulse equations approximate the solutions to the stochastic Maxwell's equations over the distances under consideration. This holds for both a pathwise comparison of the stochastic equations as well as for a comparison of the resulting probability densities.
Differential form of the Skornyakov-Ter-Martirosyan Equations
Pen'kov, F. M.; Sandhas, W.
2005-12-15
The Skornyakov-Ter-Martirosyan three-boson integral equations in momentum space are transformed into differential equations. This allows us to take into account quite directly the Danilov condition providing self-adjointness of the underlying three-body Hamiltonian with zero-range pair interactions. For the helium trimer the numerical solutions of the resulting differential equations are compared with those of the Faddeev-type AGS equations.
Thermal equation of state and spin transition of magnesiosiderite...
Office of Scientific and Technical Information (OSTI)
Citation Details In-Document Search Title: Thermal equation of ... Subject: catalysis (heterogeneous), solar (photovoltaic), phonons, thermoelectric, energy storage (including ...
The tunneling solutions of the time-dependent Schroedinger equation for a square-potential barrier
Elci, A.; Hjalmarson, H. P.
2009-10-15
The exact tunneling solutions of the time-dependent Schroedinger equation with a square-potential barrier are derived using the continuous symmetry group G{sub S} for the partial differential equation. The infinitesimal generators and the elements for G{sub S} are represented and derived in the jet space. There exist six classes of wave functions. The representative (canonical) wave functions for the classes are labeled by the eigenvalue sets, whose elements arise partially from the reducibility of a Lie subgroup G{sub LS} of G{sub S} and partially from the separation of variables. Each eigenvalue set provides two or more time scales for the wave function. The ratio of two time scales can act as the duration of an intrinsic clock for the particle motion. The exact solutions of the time-dependent Schroedinger equation presented here can produce tunneling currents that are orders of magnitude larger than those produced by the energy eigenfunctions. The exact solutions show that tunneling current can be quantized under appropriate boundary conditions and tunneling probability can be affected by a transverse acceleration.
Tailored Marketing for Low-income and Under-Represented Population...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Tailored Marketing for Low-income and Under-Represented Population Segments (201) Tailored Marketing for Low-income and Under-Represented Population Segments (201) Better Buildings ...
Gregory H. Friedman: Before the U.S. House Of Representatives...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Of Representatives Committee on Energy and Commerce Subcommittee on Oversight and Investigations Gregory H. Friedman: Before the U.S. House Of Representatives Committee on Energy ...
Examination of Hydrate Formation Methods: Trying to Create Representative Samples
Kneafsey, T.J.; Rees, E.V.L.; Nakagawa, S.; Kwon, T.-H.
2011-04-01
Forming representative gas hydrate-bearing laboratory samples is important so that the properties of these materials may be measured, while controlling the composition and other variables. Natural samples are rare, and have often experienced pressure and temperature changes that may affect the property to be measured [Waite et al., 2008]. Forming methane hydrate samples in the laboratory has been done a number of ways, each having advantages and disadvantages. The ice-to-hydrate method [Stern et al., 1996], contacts melting ice with methane at the appropriate pressure to form hydrate. The hydrate can then be crushed and mixed with mineral grains under controlled conditions, and then compacted to create laboratory samples of methane hydrate in a mineral medium. The hydrate in these samples will be part of the load-bearing frame of the medium. In the excess gas method [Handa and Stupin, 1992], water is distributed throughout a mineral medium (e.g. packed moist sand, drained sand, moistened silica gel, other porous media) and the mixture is brought to hydrate-stable conditions (chilled and pressurized with gas), allowing hydrate to form. This method typically produces grain-cementing hydrate from pendular water in sand [Waite et al., 2004]. In the dissolved gas method [Tohidi et al., 2002], water with sufficient dissolved guest molecules is brought to hydrate-stable conditions where hydrate forms. In the laboratory, this is can be done by pre-dissolving the gas of interest in water and then introducing it to the sample under the appropriate conditions. With this method, it is easier to form hydrate from more soluble gases such as carbon dioxide. It is thought that this method more closely simulates the way most natural gas hydrate has formed. Laboratory implementation, however, is difficult, and sample formation is prohibitively time consuming [Minagawa et al., 2005; Spangenberg and Kulenkampff, 2005]. In another version of this technique, a specified quantity of gas is placed in a sample, then the sample is flooded with water and cooled [Priest et al., 2009]. We have performed a number of tests in which hydrate was formed and the uniformity of the hydrate formation was examined. These tests have primarily used a variety of modifications of the excess gas method to make the hydrate, although we have also used a version of the excess water technique. Early on, we found difficulties in creating uniform samples with a particular sand/ initial water saturation combination (F-110 Sand, {approx} 35% initial water saturation). In many of our tests we selected this combination intentionally to determine whether we could use a method to make the samples uniform. The following methods were examined: Excess gas, Freeze/thaw/form, Freeze/pressurize/thaw, Excess gas followed by water saturation, Excess water, Sand and kaolinite, Use of a nucleation enhancer (SnoMax), and Use of salt in the water. Below, each method, the underlying hypothesis, and our results are briefly presented, followed by a brief conclusion. Many of the hypotheses investigated are not our own, but were presented to us. Much of the data presented is from x-ray CT scanning our samples. The x-ray CT scanner provides a three-dimensional density map of our samples. From this map and the physics that is occurring in our samples, we are able to gain an understanding of the spatial nature of the processes that occur, and attribute them to the locations where they occur.
Efficient Solution of the Simplified PN Equations
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Hamilton, Steven P; Evans, Thomas M
2015-01-01
In this paper we show new solver strategies for the multigroup SPN equations for nuclear reactor analysis. By forming the complete matrix over space, moments, and energy a robust set of solution strategies may be applied. Power iteration, shifted power iteration, Rayleigh quotient iteration, Arnoldi's method, and a generalized Davidson method, each using algebraic and physics-based multigrid preconditioners, have been compared on C5G7 MOX test problem as well as an operational PWR model. Our results show that the most ecient approach is the generalized Davidson method, that is 30{40 times faster than traditional power iteration and 6{10 times faster thanmore » Arnoldi's method.« less
The Raychaudhuri equation in homogeneous cosmologies
Albareti, F.D.; Cembranos, J.A.R.; Cruz-Dombriz, A. de la; Dobado, A. E-mail: cembra@fis.ucm.es E-mail: dobado@fis.ucm.es
2014-03-01
In this work we address the issue of studying the conditions required to guarantee the Focusing Theorem for both null and timelike geodesic congruences by using the Raychaudhuri equation. In particular we study the case of Friedmann-Robertson-Walker as well as more general Bianchi Type I spacetimes. The fulfillment of the Focusing Theorem is mandatory in small scales since it accounts for the attractive character of gravity. However, the Focusing Theorem is not satisfied at cosmological scales due to the measured negative deceleration parameter. The study of the conditions needed for congruences convergence is not only relevant at the fundamental level but also to derive the viability conditions to be imposed on extended theories of gravity describing the different expansion regimes of the universe. We illustrate this idea for f(R) gravity theories.
Equations determine coiled tubing collapse pressure
Avakov, V.; Taliaferro, W.
1995-07-24
A set of equations has been developed for calculating pipe collapse pressure for oval tubing such as coiled tubing. When coiled tubing is placed onto a reel, the tubing is forced into an oval shape and never again returns to perfect roundness because the coiling process exceeds the plasticity limits of the tubing. Straightening the tubing for the trip into the well does not restore roundness. The consequence of this physical property is that all coiled tubing collapse pressure calculations should be made considering oval tubing, not round tubing. Tubing collapse can occur when formation pressure against the coiled tubing exceeds the collapse resistance inherent in the coiled tubing. As coiled tubing becomes more oval in shape, it becomes more oval in shape, it becomes more susceptible to collapse from outside pressure.
Assessment of UF6 Equation of State
Brady, P; Chand, K; Warren, D; Vandersall, J
2009-02-11
A common assumption in the mathematical analysis of flows of compressible fluids is to treat the fluid as a perfect gas. This is an approximation, as no real fluid obeys the perfect gas relationships over all temperature and pressure conditions. An assessment of the validity of treating the UF{sub 6} gas flow field within a gas centrifuge with perfect gas relationships has been conducted. The definition of a perfect gas is commonly stated in two parts: (1) the gas obeys the thermal equation of state, p = {rho}RT (thermally perfect), and, (2) the gas specific heats are constant (calorically perfect). Analysis indicates the thermally perfect assumption is valid for all flow conditions within the gas centrifuge, including shock fields. The low operating gas pressure is the primary factor in the suitability of the thermally perfect equation of state for gas centrifuge computations. UF{sub 6} is not calorically perfect, as the specific heats vary as a function of temperature. This effect is insignificant within the bulk of the centrifuge gas field, as gas temperatures vary over a narrow range. The exception is in the vicinity of shock fields, where temperature, pressure, and density gradients are large, and the variation of specific heats with temperature should be included in the technically detailed analyses. Results from a normal shock analysis incorporating variable specific heats is included herein, presented in the conventional form of shock parameters as a function of inlet Mach Number. The error introduced by assuming constant specific heats is small for a nominal UF{sub 6} shock field, such that calorically perfect shock relationships can be used for scaling and initial analyses. The more rigorous imperfect gas analysis should be used for detailed analyses.
Real-time and imaginary-time quantum hierarchal Fokker-Planck equations
Tanimura, Yoshitaka
2015-04-14
We consider a quantum mechanical system represented in phase space (referred to hereafter as “Wigner space”), coupled to a harmonic oscillator bath. We derive quantum hierarchal Fokker-Planck (QHFP) equations not only in real time but also in imaginary time, which represents an inverse temperature. This is an extension of a previous work, in which we studied a spin-boson system, to a Brownian system. It is shown that the QHFP in real time obtained from a correlated thermal equilibrium state of the total system possesses the same form as those obtained from a factorized initial state. A modified terminator for the hierarchal equations of motion is introduced to treat the non-Markovian case more efficiently. Using the imaginary-time QHFP, numerous thermodynamic quantities, including the free energy, entropy, internal energy, heat capacity, and susceptibility, can be evaluated for any potential. These equations allow us to treat non-Markovian, non-perturbative system-bath interactions at finite temperature. Through numerical integration of the real-time QHFP for a harmonic system, we obtain the equilibrium distributions, the auto-correlation function, and the first- and second-order response functions. These results are compared with analytically exact results for the same quantities. This provides a critical test of the formalism for a non-factorized thermal state and elucidates the roles of fluctuation, dissipation, non-Markovian effects, and system-bath coherence. Employing numerical solutions of the imaginary-time QHFP, we demonstrate the capability of this method to obtain thermodynamic quantities for any potential surface. It is shown that both types of QHFP equations can produce numerical results of any desired accuracy. The FORTRAN source codes that we developed, which allow for the treatment of Wigner space dynamics with any potential form (TanimuranFP15 and ImTanimuranFP15), are provided as the supplementary material.
Dirac Equation and Quantum Relativistic Effects in a Single Trapped Ion
Lamata, L.; Leon, J.; Schaetz, T.; Solano, E.
2007-06-22
We present a method of simulating the Dirac equation in 3+1 dimensions for a free spin-1/2 particle in a single trapped ion. The Dirac bispinor is represented by four ionic internal states, and position and momentum of the Dirac particle are associated with the respective ionic variables. We show also how to simulate the simplified 1+1 case, requiring the manipulation of only two internal levels and one motional degree of freedom. Moreover, we study relevant quantum-relativistic effects, like the Zitterbewegung and Klein's paradox, the transition from massless to massive fermions, and the relativistic and nonrelativistic limits, via the tuning of controllable experimental parameters.
A Reconstructed Discontinuous Galerkin Method for the Euler Equations on
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Arbitrary Grids (Journal Article) | SciTech Connect Reconstructed Discontinuous Galerkin Method for the Euler Equations on Arbitrary Grids Citation Details In-Document Search Title: A Reconstructed Discontinuous Galerkin Method for the Euler Equations on Arbitrary Grids A reconstruction-based discontinuous Galerkin (RDG(P1P2)) method, a variant of P1P2 method, is presented for the solution of the compressible Euler equations on arbitrary grids. In this method, an in-cell reconstruction,
Validity of ELTB Equation for Suitable Description of BEC
Kim, Dooyoung; Kim, Jinguanghao; Yoon, Jin-Hee
2005-10-17
The Bose-Einstein condensation (BEC) has been found for various alkali-metal gases such as 7Li, 87Rb, Na, and H. For the description of atoms in this condensate state, the Gross-Pitaevskii (GP) equation has been widely used. However, the GP equation contains the nonlinear term, which makes this equation hard to solve. Therefore, physical quantities are usually obtained numerically, and sometimes it is difficult to extract a physical meaning from the calculated results. The nuclear theory group at Purdue University in the U.S. developed a new simple equation, the equivalent linear two-body (ELTB) equation, using the hyper-radius coordinates and tested it for one-dimensional BEC system. Their results are consistent with the numerical values from the GP equation within 4.5%.We test the validity of the ELTB equation for three-dimensional BEC system by calculating the energies per particle and the wave functions for 87Rb gas and for 7Li gas. We use the quantum-mechanical variational method for the BEC energy. Our result for 87Rb gas agrees with a numerical calculation based on the GP equation, with a relative error of 12% over a wide range of N from 100 to 10,000. The relative distances between particles for 7Li gas are consistent within a relative error of 17% for N {<=} 1300. The relatively simple form of the ELTB equation, compared with the GP equation, enables us to treat the N-body system easily and efficiently. We conclude that the ELTB equation is a powerful equation for describing BEC system because it is easy to treat.
SCIENCE ON SATURDAY- "Disastrous Equations: The Role of Mathematics...
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SCIENCE ON SATURDAY- "Disastrous Equations: The Role of Mathematics in Understanding Tsunami" Professor J. Douglas Wright, Associate Professor Department of Mathematics, Drexel ...
An Acoustic Wave Equation for Tilted Transversely Isotropic Media...
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Citation Details In-Document Search Title: An Acoustic Wave Equation for Tilted Transversely Isotropic Media A finite-difference method for computing the first arrival traveltimes ...
Scientists compose complex math equations to replicate behaviors...
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Climate Models: Rob Jacob Scientists compose complex math equations to replicate behaviors ... It's math in action. A global model depends on submodels Submodels can be broken into two ...
Solving the power flow equations: a monotone operator approach...
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The AC power flow equations underlie all operational aspects of power systems. They are solved routinely in operational practice using the Newton-Raphson method and its variants. ...
Strategic Petroleum Reserve equation of state model development...
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Strategic Petroleum Reserve equation of state model development : current performance against measured data. Citation Details In-Document Search Title: Strategic Petroleum Reserve ...
Felix Bloch, Nuclear Induction, Bloch Equations, Bloch Theorem...
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Felix Bloch, Nuclear Induction, and Bloch Equations Resources with Additional Information ... for the 'development of new methods for nuclear magnetic precision measurements and ...
Stochastic finite element methods for partial differential equations...
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Journal Article: Stochastic finite element methods for partial differential equations with random input data Citation Details In-Document Search Title: Stochastic finite element ...
Penetration equations Young, C.W. [Applied Research Associates...
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45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEFENSE; EARTH PENETRATORS; EQUATIONS; NUCLEAR WEAPONS; SOILS; ICE; ROCKS; CONCRETES; PERMAFROST; SCALING LAWS In 1967, Sandia...
Covariant functional diffusion equation for Polyakov's bosonic string
Botelho, L. C. L.
1989-07-15
I write a covariant functional diffusion equation for Polyakov's bosonic string with the string's world-sheet area playing the role of proper time.
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... facilities under a single lineprogram manager within the ... unique position in the transmission of information between ... performance, any areas of theory or fundamentals, if any, ...
Fact #734: July 2, 2012 OPEC Countries Represent Less Than Half...
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Represent Less Than Half of U.S. Petroleum Imports Fact 734: July 2, 2012 OPEC Countries Represent Less Than Half of U.S. Petroleum Imports Even though Saudi Arabia is the ...
Gregory H. Friedman: Before the U.S. House of Representatives...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Government Reform Gregory H. Friedman: Before the U.S. House of Representatives Committee on Government Reform March 20, 2003 Before the U.S. House of Representatives Committee on ...
Slyusarchuk, V. E. E-mail: V.Ye.Slyusarchuk@NUWM.rv.ua
2014-06-01
The well-known theorems of Favard and Amerio on the existence of almost periodic solutions to linear and nonlinear almost periodic differential equations depend to a large extent on the H-classes and the requirement that the bounded solutions of these equations be separated. The present paper provides different conditions for the existence of almost periodic solutions. These conditions, which do not depend on the H-classes of the equations, are formulated in terms of a special functional on the set of bounded solutions of the equations under consideration. This functional is used, in particular, to test whether solutions are separated. Bibliography: 24 titles. (paper)
Stochastic differential equations and numerical simulation for pedestrians
Garrison, J.C.
1993-07-27
The mathematical foundation of the Ito interpretation of stochastic ordinary and partial differential equations is briefly explained. This provides the basis for a review of simple difference approximations to stochastic differential equations. An example arising in the theory of optical switching is discussed.
Stable Difference Schemes for the Neutron Transport Equation
Ashyralyev, Allaberen; Taskin, Abdulgafur
2011-09-22
The initial boundary value problem for the neutron transport equation is considered. The first and second orders of accuracy difference schemes for the approximate solution of this problem are presented. In applications, the stability estimates for solutions of difference schemes for the approximate solution of the neutron transport equation are obtained. Numerical techniques are developed and algorithms are tested on an example in MATLAB.
The modified equation for spinless particles and superalgebra
Sadeghi, J.; Rostami, M.; Sadeghi, Z.
2013-09-15
In this paper we consider modified wave equations for spinless particles in an external magnetic field. We consider 4-potentials which guarantee Lorentz' and Coulomb's conditions. The new variable for modified wave equation leads us to consider the associated Laguerre differential equation. We take advantage of the factorization method in Laguerre differential equation and solve the modified equation. In order to obtain the wave function, energy spectrum and its quantization, we will establish conditions for the orbital quantum number. We account such orbital quantum number and obtain the raising and lowering operators. If we want to have supersymmetry partners, we need to apply the shape invariance condition. This condition for the partner potential will help us find the limit of ? as ?=?(l)
BHR equations re-derived with immiscible particle effects
Schwarzkopf, John Dennis; Horwitz, Jeremy A.
2015-05-01
Compressible and variable density turbulent flows with dispersed phase effects are found in many applications ranging from combustion to cloud formation. These types of flows are among the most challenging to simulate. While the exact equations governing a system of particles and fluid are known, computational resources limit the scale and detail that can be simulated in this type of problem. Therefore, a common method is to simulate averaged versions of the flow equations, which still capture salient physics and is relatively less computationally expensive. Besnard developed such a model for variable density miscible turbulence, where ensemble-averaging was applied to the flow equations to yield a set of filtered equations. Besnard further derived transport equations for the Reynolds stresses, the turbulent mass flux, and the density-specific volume covariance, to help close the filtered momentum and continuity equations. We re-derive the exact BHR closure equations which include integral terms owing to immiscible effects. Physical interpretations of the additional terms are proposed along with simple models. The goal of this work is to extend the BHR model to allow for the simulation of turbulent flows where an immiscible dispersed phase is non-trivially coupled with the carrier phase.
New Dirac equation from the view point of particle
Ozaydin, Fatih; Altintas, Azmi Ali; Susam, Lidya Amon; Arik, Metin; Yarman, Tolga
2012-09-06
According to the classical approach, especially the Lorentz Invariant Dirac Equation, when particles are bound to each other, the interaction term appears as a quantity belonging to the 'field'. In this work, as a totally new approach, we propose to alter the rest masses of the particles due to their interaction, as much as their respective contributions to the static binding energy. Thus we re-write and solve the Dirac Equation for the hydrogen atom, and amazingly, obtain practically the same numerical results for the ground states, as those obtained from the Dirac Equation.
Variational principles for eigenvalues of the Klein-Gordon equation
Langer, Matthias; Tretter, Christiane
2006-10-15
In this paper variational principles for eigenvalues of an abstract model of the Klein-Gordon equation with electromagnetic potential are established. They are used to characterize and estimate eigenvalues in cases where the essential spectrum has a gap around 0, even in the presence of complex eigenvalues. As a consequence, a comparison between eigenvalues of the Klein-Gordon equation in R{sup d} and eigenvalues of certain Schroedinger operators is obtained. The results are illustrated on examples including the Klein-Gordon equation with Coulomb and square-well potential.
The fundamental solution of the unidirectional pulse propagation equation
Babushkin, I.; Bergé, L.
2014-03-15
The fundamental solution of a variant of the three-dimensional wave equation known as “unidirectional pulse propagation equation” (UPPE) and its paraxial approximation is obtained. It is shown that the fundamental solution can be presented as a projection of a fundamental solution of the wave equation to some functional subspace. We discuss the degree of equivalence of the UPPE and the wave equation in this respect. In particular, we show that the UPPE, in contrast to the common belief, describes wave propagation in both longitudinal and temporal directions, and, thereby, its fundamental solution possesses a non-causal character.
Exact solution of the self-consistent Vlasov equation
Morawetz, K.
1997-03-01
An analytical solution of the self-consistent Vlasov equation is presented. The time evolution is entirely determined by the initial distribution function. The largest Lyapunov exponent is calculated analytically. For special parameters of the potential a positive Lyapunov exponent is possible. This model may serve as a check for numerical codes solving self-consistent Vlasov equations. The here presented method is also applicable for any system with an analytical solution of the Hamilton equation for the form factor of the potential. {copyright} {ital 1997} {ital The American Physical Society}
Gregory H. Friedman: Before The U.S. House of Representatives Committee on
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Government Reform Subcommittee on the Federal Workforce and Agency Organization | Department of Energy The U.S. House of Representatives Committee on Government Reform Subcommittee on the Federal Workforce and Agency Organization Gregory H. Friedman: Before The U.S. House of Representatives Committee on Government Reform Subcommittee on the Federal Workforce and Agency Organization April 5 2005 Before The U.S. House of Representatives Committee on Government Reform Subcommittee on the
Gregory H. Friedman: Before the U.S. House Of Representatives Committee on
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Energy and Commerce Subcommittee on Oversight and Investigations | Department of Energy Of Representatives Committee on Energy and Commerce Subcommittee on Oversight and Investigations Gregory H. Friedman: Before the U.S. House Of Representatives Committee on Energy and Commerce Subcommittee on Oversight and Investigations May 1, 2003 Before the U.S. House Of Representatives Committee on Energy and Commerce Subcommittee on Oversight and Investigations Statement of Gregory H. Friedman,
Gregory H. Friedman: Before the U.S. House of Representatives Committee on
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Energy and Commerce Subcommittee on Oversight and Investigations | Department of Energy of Representatives Committee on Energy and Commerce Subcommittee on Oversight and Investigations Gregory H. Friedman: Before the U.S. House of Representatives Committee on Energy and Commerce Subcommittee on Oversight and Investigations February 26, 2003 Before the U.S. House of Representatives Committee on Energy and Commerce Subcommittee on Oversight and Investigations Statement of Gregory H. Friedman,
Herbert Richardson: Before The U.S. House of Representatives Committee on
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Energy and Commerce Subcommittee on Oversight and Investigations | Department of Energy Herbert Richardson: Before The U.S. House of Representatives Committee on Energy and Commerce Subcommittee on Oversight and Investigations Herbert Richardson: Before The U.S. House of Representatives Committee on Energy and Commerce Subcommittee on Oversight and Investigations March 4, 2004 Before The U.S. House of Representatives Committee on Energy and Commerce Subcommittee on Oversight and
Secretary Chu to Join Representatives Lofgren and Honda at the SLAC
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National Accelerator Laboratory | Department of Energy Representatives Lofgren and Honda at the SLAC National Accelerator Laboratory Secretary Chu to Join Representatives Lofgren and Honda at the SLAC National Accelerator Laboratory August 13, 2010 - 12:00am Addthis Washington, D.C. - On Monday, U.S. Energy Secretary Steven Chu will visit the SLAC National Accelerator Laboratory in Menlo Park, California. Secretary Chu will join Representatives Zoe Lofgren and Mike Honda and Stanford
4Q CY2002 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
Attached is the Facility Representative Program Performance Indicators (Pis) Quarterly Report Covering the Period from October to December 2002. Data for these indicators are gathered by Field...
2Q CY2005 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
Attached is the Facility Representative (FR) Program Performance Indicators Quarterly Report covering the period from April to June 2005. Data for these indicators are gathered by Field elements...
1Q CY2005 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
Attached is the Facility Representative (FR) Program Performance Indicators Quarterly Report covering the period from January to March 2005. Data for these indicators are gathered by Field elements...
2Q CY2006 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
Attached is the Facility Representative (FR) Program Performance Indicators Quarterly Report covering the period from April to June 2006. Data for these indicators are gathered by Field elements...
4Q CY2005 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
Attached is the Facility Representative (FR) Program Performance Indicators Quarterly Report covering the period from October to December 2005. Data for these indicators are gathered by Field...
2Q CY2011 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
"This memorandum summarizes the Facility Representative (FR) Program Performance Indicators Quarterly Report covering the period April through June 20 1 1. Data for these indicators were gathered...
Tailored Marketing for Low-income and Under-Represented Population Segments (201)
Broader source: Energy.gov [DOE]
Better Buildings Residential Network Peer Exchange Call Series: Tailored Marketing for Low-Income and Under-Represented Population Segments (201), call slides and discussion summary.
3Q CY2007 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
Attached is the Facility Representative (FR) Program Performance Indicators Quarterly Report covering the period from July to September 2007. Data for these indicators are gathered by Field...
2Q CY2008 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
Attached is the Facility Representative (FR) Program Performance Indicators QuarterlyReport covering the period from April to June 2008. Data for these indicators aregathered by Field elements...
4Q CY2010 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
"This memorandum summarizes the highlights of the Facility Representative (FR) Program Performance Indicators Quarterly Report covering the period October through December 2010. Data for these...
3Q CY2011 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
This memorandum summarizes the Facility Representative (FR) Program Performance Indicators Quarterly Report covering the Period July through September 2011. Data for these indicators were gathered...
1Q CY2011 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
This memorandum summarizes the Facility Representative (FR) Program Performance Indicators Quarterly Report covering the Period January through March 2011. Data for these indicators were gathered...
2Q CY2012 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
"This memorandum summarizes the Facility Representative (FR) Program Performance Indicators Quarterly Report covering the period from April through June 2012. Data for these indicators were...
3Q CY2010 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
This memorandum summarizes the highlights of the Facility Representative (FR) Program Performance Indicators Quarterly Report covering the period of July through September 2010. Data for these...
1Q CY2007 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
Attached is the Facility Representative (FR) Program Performance Indicators Quarterly Report covering the period from January to March 2007. Data for these indicators are gathered by Field elements...
4Q CY2006 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
Attached is the Facility Representative (FR) Program Performance Indicators Quarterly Report covering the period from October to December 2006. Data for these indicators are gathered by Field...
2Q CY2010 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
This memorandum summarizes the highlight of, and announces the availablity on-line of, the Facility Representative (FR) Program Performance Indicators are gathered by Field elements quarterly per...
3Q CY2000 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
The Facility Representative Program Indicators (Pis) Quarterly Report attached, covering the period from July to September 2000. Data for these indicators are gathered by the Field elements...
Gregory H. Friedman: Before the U.S. House of Representatives...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Energy and Commerce Subcommittee on Oversight and Investigations Gregory H. Friedman: Before the U.S. House of Representatives Committee on Energy and Commerce Subcommittee on ...
2Q CY2007 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
Attached is the Facility Representative (FR) Program Performance Indicators Quarterly Report covering the period from April to June 2007. Data for these indicators are gathered by field elements...
DOE Orders Self-Study Program- DOE-STD-1063-2011, Facility Representatives
Broader source: Energy.gov [DOE]
U.S. Department of Energy Orders Self-Study Program DOE-STD-1063-2011, Facility Representatives Familiar Level - August 2011
4Q CY2007 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
"Attached is the Facility Representative (FR) Program Performance Indicators QuarterlyReport covering the period from October to December 2007. Data for these indicators aregathered by Field...
3Q CY2005 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
Attached is the Facility Representative (FR) Program Performance Indicators Quarterly Report covering the period from July to September 2005. Data for these indicators are gathered by Field...
1Q CY2012 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
This memorandum summarizes the Facility Representative (FR) Program Performance Indicators Quarterly Report covering the period from January through March 2012. Data for these indicators were...
4Q CY2011 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
"This memorandum summarizes the Facility Representative (FR) Program Performance Indicators Quarterly Report covering the period from October through December 2011. Data for these indicators were...
3Q CY2006 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
Attached is the Facility Representative (FR) Program Performance Indicators Quarterly Report covering the period from July to September 2006. Data for these indicators are gathered by Field...
Equator Appliance: ENERGY STAR Referral (EZ 3720 CEE)
Broader source: Energy.gov [DOE]
DOE referred the matter of Equator clothes washer model EZ 3720 CEE to the EPA for appropriate action after DOE testing showed that the model does not meet the ENERGY STAR specification.
Electrolux Gibson Air Conditioner and Equator Clothes Washer...
Broader source: Energy.gov (indexed) [DOE]
ENERGY STAR program has revealed that an Electrolux Gibson air conditioner (model GAH105Q2T1) and an Equator clothes washer (model EZ 3720 CEE), both of which claimed ENERGY STAR...
Development of one-equation transition/turbulence models
Edwards, J.R.; Roy, C.J.; Blottner, F.G.; Hassan, H.A.
2000-01-14
This paper reports on the development of a unified one-equation model for the prediction of transitional and turbulent flows. An eddy viscosity--transport equation for nonturbulent fluctuation growth based on that proposed by Warren and Hassan is combined with the Spalart-Allmaras one-equation model for turbulent fluctuation growth. Blending of the two equations is accomplished through a multidimensional intermittency function based on the work of Dhawan and Narasimha. The model predicts both the onset and extent of transition. Low-speed test cases include transitional flow over a flat plate, a single element airfoil, and a multi-element airfoil in landing configuration. High-speed test cases include transitional Mach 3.5 flow over a 5{degree} cone and Mach 6 flow over a flared-cone configuration. Results are compared with experimental data, and the grid-dependence of selected predictions is analyzed.
Stochastic finite element methods for partial differential equations with
Office of Scientific and Technical Information (OSTI)
random input data (Journal Article) | SciTech Connect Journal Article: Stochastic finite element methods for partial differential equations with random input data Citation Details In-Document Search Title: Stochastic finite element methods for partial differential equations with random input data Authors: Gunzburger, Max D [1] ; Webster, Clayton G [1] ; Zhang, Guannan [1] + Show Author Affiliations ORNL Publication Date: 2014-01-01 OSTI Identifier: 1159494 DOE Contract Number:
Adjoint Fokker-Planck equation and runaway electron dynamics (Journal
Office of Scientific and Technical Information (OSTI)
Article) | SciTech Connect Adjoint Fokker-Planck equation and runaway electron dynamics Citation Details In-Document Search This content will become publicly available on January 13, 2017 Title: Adjoint Fokker-Planck equation and runaway electron dynamics Authors: Liu, Chang [1] ; Brennan, Dylan P. [1] ; Bhattacharjee, Amitava [1] ; Boozer, Allen H. [2] + Show Author Affiliations Princeton University, Princeton, New Jersey 08544, USA Columbia University, New York, New York 10027, USA
Notes on the Lumped Backward Master Equation for the Neutron
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Extinction/Survival Probability (Technical Report) | SciTech Connect Technical Report: Notes on the Lumped Backward Master Equation for the Neutron Extinction/Survival Probability Citation Details In-Document Search Title: Notes on the Lumped Backward Master Equation for the Neutron Extinction/Survival Probability The expected or mean neutron number (or density) provides an adequate characterization of the neutron population and its dynamical excursions in most neutronic applications, in
Renormalization group equations in a model of generalized hidden local
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symmetry and restoration of chiral symmetry (Journal Article) | SciTech Connect Renormalization group equations in a model of generalized hidden local symmetry and restoration of chiral symmetry Citation Details In-Document Search Title: Renormalization group equations in a model of generalized hidden local symmetry and restoration of chiral symmetry We study possible restoration patterns of chiral symmetry in a generalized hidden local symmetry model, which is a low-energy effective theory
Renormalization group functional equations (Journal Article) | SciTech
Office of Scientific and Technical Information (OSTI)
Connect group functional equations Citation Details In-Document Search Title: Renormalization group functional equations Authors: Curtright, Thomas L. ; Zachos, Cosmas K. Publication Date: 2011-03-16 OSTI Identifier: 1100055 Type: Publisher's Accepted Manuscript Journal Name: Physical Review D Additional Journal Information: Journal Volume: 83; Journal Issue: 6; Journal ID: ISSN 1550-7998 Publisher: American Physical Society Sponsoring Org: USDOE Country of Publication: United States
Multifractal analysis of time series generated by discrete Ito equations
Telesca, Luciano; Czechowski, Zbigniew; Lovallo, Michele
2015-06-15
In this study, we show that discrete Ito equations with short-tail Gaussian marginal distribution function generate multifractal time series. The multifractality is due to the nonlinear correlations, which are hidden in Markov processes and are generated by the interrelation between the drift and the multiplicative stochastic forces in the Ito equation. A link between the range of the generalized Hurst exponents and the mean of the squares of all averaged net forces is suggested.
Multibump solutions for quasilinear elliptic equations with critical growth
Liu, Jiaquan; Wang, Zhi-Qiang; Wu, Xian
2013-12-15
The current paper is concerned with constructing multibump solutions for a class of quasilinear Schrdinger equations with critical growth. This extends the classical results of Coti Zelati and Rabinowitz [Commun. Pure Appl. Math. 45, 12171269 (1992)] for semilinear equations as well as recent work of Liu, Wang, and Guo [J. Funct. Anal. 262, 40404102 (2012)] for quasilinear problems with subcritical growth. The periodicity of the potentials is used to glue ground state solutions to construct multibump bound state solutions.
Broader source: Energy.gov [DOE]
The purpose of this flash is to provide interim guidance for certifying and appointing Contracting Officer's Representatives. This guidance complies with the Office of Federal Procurement Policy memorandum, Revisions to the Federal Acquisition Certification for Contracting Officer's Representatives (FAC-COR), dated September 6, 2011 with an effective date of January 1, 2012.
Bressloff, N.W.; Moss, J.B.; Rubini, P.A.
1997-01-01
The differential total absorptivity (DTA) solution to the radiative transfer equation, originally devised for combustion gases in the discrete transfer radiation model, is extended to mixtures of gaseous combustion products and soot. The method is compared to other solution techniques for representative mixtures across single lines of sight and across a layer bounded by solid walls. Intermediate soot loadings are considered such that the total radiance is not dominated by either the gaseous or soot components. The DTA solution is shown to yield excellent accuracy relative to a narrow-band solution, with a considerable saving in computational cost. Thus, explicit treatment of the source temperature dependence of absorption is successfully demonstrated without the need for spectral integration.
Bhaskaran-Nair, Kiran; Kowalski, Karol; Jarrell, Mark; Moreno, Juana; Shelton, William A.
2015-11-05
Polyacenes have attracted considerable attention due to their use in organic based optoelectronic materials. Polyacenes are polycyclic aromatic hydrocarbons composed of fused benzene rings. Key to understanding and design of new functional materials is an understanding of their excited state properties starting with their electron affinity (EA) and ionization potential (IP). We have developed a highly accurate and com- putationally e*fficient EA/IP equation of motion coupled cluster singles and doubles (EA/IP-EOMCCSD) method that is capable of treating large systems and large basis set. In this study we employ the EA/IP-EOMCCSD method to calculate the electron affinity and ionization potential of naphthalene, anthracene, tetracene, pentacene, hex- acene and heptacene. We have compared our results with other previous theoretical studies and experimental data. Our EA/IP results are in very good agreement with experiment and when compared with the other theoretical investigations our results represent the most accurate calculations as compared to experiment.
Secretary Chu: China's Clean Energy Successes Represent a New "Sputnik
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Moment" for America | Department of Energy Chu: China's Clean Energy Successes Represent a New "Sputnik Moment" for America Secretary Chu: China's Clean Energy Successes Represent a New "Sputnik Moment" for America November 29, 2010 - 12:00am Addthis Washington, D.C. - In a speech at the National Press Club, U.S Energy Secretary Steven Chu said that the success of China and other countries in clean energy industries represents a new "Sputnik Moment" for the
Optimization of High-order Wave Equations for Multicore CPUs
Energy Science and Technology Software Center (OSTI)
2011-11-01
This is a simple benchmark to guage the performance of a high-order isotropic wave equation grid. The code is optimized for both SSE and AVX and is parallelized using OpenMP (see Optimization section). Structurally, the benchmark begins, reads a few command-line parameters, allocates and pads the four arrays (current, last, next wave fields, and the spatially varying but isotropic velocity), initializes these arrays, then runs the benchmark proper. The code then benchmarks the naive, SSEmore » (if supported), and AVX (if supported implementations) by applying the wave equation stencil 100 times and taking the average performance. Boundary conditions are ignored and would noiminally be implemented by the user. THus, the benchmark measures only the performance of the wave equation stencil and not a full simulation. The naive implementation is a quadruply (z,y,x, radius) nested loop that can handle arbitrarily order wave equations. The optimized (SSE/AVX) implentations are somewhat more complex as they operate on slabs and include a case statement to select an optimized inner loop depending on wave equation order.« less
Handbook of Industrial Engineering Equations, Formulas, and Calculations
Badiru, Adedeji B; Omitaomu, Olufemi A
2011-01-01
The first handbook to focus exclusively on industrial engineering calculations with a correlation to applications, Handbook of Industrial Engineering Equations, Formulas, and Calculations contains a general collection of the mathematical equations often used in the practice of industrial engineering. Many books cover individual areas of engineering and some cover all areas, but none covers industrial engineering specifically, nor do they highlight topics such as project management, materials, and systems engineering from an integrated viewpoint. Written by acclaimed researchers and authors, this concise reference marries theory and practice, making it a versatile and flexible resource. Succinctly formatted for functionality, the book presents: Basic Math Calculations; Engineering Math Calculations; Production Engineering Calculations; Engineering Economics Calculations; Ergonomics Calculations; Facility Layout Calculations; Production Sequencing and Scheduling Calculations; Systems Engineering Calculations; Data Engineering Calculations; Project Engineering Calculations; and Simulation and Statistical Equations. It has been said that engineers make things while industrial engineers make things better. To make something better requires an understanding of its basic characteristics and the underlying equations and calculations that facilitate that understanding. To do this, however, you do not have to be computational experts; you just have to know where to get the computational resources that are needed. This book elucidates the underlying equations that facilitate the understanding required to improve design processes, continuously improving the answer to the age-old question: What is the best way to do a job?
Solving the Bateman equations in CASMO5 using implicit ode numerical methods for stiff systems
Hykes, J. M.; Ferrer, R. M.
2013-07-01
The Bateman equations, which describe the transmutation of nuclides over time as a result of radioactive decay, absorption, and fission, are often numerically stiff. This is especially true if short-lived nuclides are included in the system. This paper describes the use of implicit numerical methods for o D Es applied to the stiff Bateman equations, specifically employing the Backward Differentiation Formulas (BDF) form of the linear multistep method. As is true in other domains, using an implicit method removes or lessens the (sometimes severe) step-length constraints by which explicit methods must abide. To gauge its accuracy and speed, the BDF method is compared to a variety of other solution methods, including Runge-Kutta explicit methods and matrix exponential methods such as the Chebyshev Rational Approximation Method (CRAM). A preliminary test case was chosen as representative of a PWR lattice depletion step and was solved with numerical libraries called from a Python front-end. The Figure of Merit (a combined measure of accuracy and efficiency) for the BDF method was nearly identical to that for CRAM, while explicit methods and other matrix exponential approximations trailed behind. The test case includes 319 nuclides, in which the shortest-lived nuclide is {sup 98}Nb with a half-life of 2.86 seconds. Finally, the BDF and CRAM methods were compared within CASMO5, where CRAM had a FOM about four times better than BDF, although the BDF implementation was not fully optimized. (authors)
Implementation of two-equation soot flamelet models for laminar diffusion flames
Carbonell, D.; Oliva, A.; Perez-Segarra, C.D.
2009-03-15
The two-equation soot model proposed by Leung et al. [K.M. Leung, R.P. Lindstedt, W.P. Jones, Combust. Flame 87 (1991) 289-305] has been derived in the mixture fraction space. The model has been implemented using both Interactive and Non-Interactive flamelet strategies. An Extended Enthalpy Defect Flamelet Model (E-EDFM) which uses a flamelet library obtained neglecting the soot formation is proposed as a Non-Interactive method. The Lagrangian Flamelet Model (LFM) is used to represent the Interactive models. This model uses direct values of soot mass fraction from flamelet calculations. An Extended version (E-LFM) of this model is also suggested in which soot mass fraction reaction rates are used from flamelet calculations. Results presented in this work show that the E-EDFM predict acceptable results. However, it overpredicts the soot volume fraction due to the inability of this model to couple the soot and gas-phase mechanisms. It has been demonstrated that the LFM is not able to predict accurately the soot volume fraction. On the other hand, the extended version proposed here has been shown to be very accurate. The different flamelet mathematical formulations have been tested and compared using well verified reference calculations obtained solving the set of the Full Transport Equations (FTE) in the physical space. (author)
Cluster virial expansion for the equation of state of partially ionized hydrogen plasma
Omarbakiyeva, Y. A.; Fortmann, C.; Ramazanov, T. S.; Roepke, G.
2010-08-15
We study the contribution of electron-atom interaction to the equation of state for partially ionized hydrogen plasma using the cluster-virial expansion. We use the Beth-Uhlenbeck approach to calculate the second virial coefficient for the electron-atom (bound cluster) pair from the corresponding scattering phase shifts and binding energies. Experimental scattering cross-sections as well as phase shifts calculated on the basis of different pseudopotential models are used as an input for the Beth-Uhlenbeck formula. By including Pauli blocking and screening in the phase shift calculation, we generalize the cluster-virial expansion in order to cover also near solid density plasmas. We present results for the electron-atom contribution to the virial expansion and the corresponding equation of state, i.e. pressure, composition, and chemical potential as a function of density and temperature. These results are compared with semiempirical approaches to the thermodynamics of partially ionized plasmas. Avoiding any ill-founded input quantities, the Beth-Uhlenbeck second virial coefficient for the electron-atom interaction represents a benchmark for other, semiempirical approaches.
3Q CY2004 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
Attached is the Facility Representative (FR) Program Performance Indicators Quarterly Report Covering the Period from July to September 2004. Data for these indicators are gathered by Field...
1Q CY2006 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
Attached is the Facility Representative (FR) Program Performance Indicators Quarterly Report covering the period from January to March 2006. Data for these indicators are gathered by Field...
John C. Barnes of Savannah River Operations named 2012 Facility Representative of the Year
Broader source: Energy.gov [DOE]
About 200 Department of Energy (DOE) federal employees are Facility Representatives (FR) who provide day-to-day oversight of contractor operations at DOE facilities. Each year the Department...
1Q CY2009 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
"Attached is the Facility Representative (FR) Program Performance Indicators Quarterly Report covering the period from January to March 2009. Data for these indicators are gathered by Field...
4Q CY2008 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
"Attached is the Facility Representative (FR) Program Performance Indicators Quarterly Report covering the period from October to December 2008. Data for these indicators are gathered by Field...
2Q CY2000 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
"The Facility Representative Program Performance Indicators (PIs) Quarterly Report is attached, covering the period from April 2000 to June 2000. Data for these indicators are gathered by the Field...
4Q CY2009 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
"Attached is the Facility Representative (FR) Program Performance Indicators Quarterly Report covering the period from October to December 2009. Data for these indicators are gathered by Field...
3Q CY2009 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
Attached is the Facility Representative (FR) Program Performance Indicators Quarterly Report covering the period from July to September 2009. Data for these indicators are gathered by Field...
Gregory H. Friedman: Before the U.S. House of Representatives...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Gregory H. Friedman: Before the U.S. House of Representatives Committee on Energy and ... Statement of Gregory H. Friedman, Inspector General U.S. Department of Energy Testify on ...
4Q CY2004 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
Attached is the Facility Representative (FR) Program Performance Indicators Quarterly Report Covering the Period from October to December 2004. Data for these indicators are gathered by Field...
1Q CY2010 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
"Attached is the Facility Representative (FR) Program Performance Indicators Quarterly Report covering the period from January to March2010. Data for these indicators are gathered by Field...
3Q C&2008 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
"Attached is the Facility Representative (FR) Program Performance Indicators Quarterly Report covering the period from July to September 2008. Data for these indicators aregathered by Field...
Gregory H. Friedman: Before The U.S. House of Representatives...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
The U.S. House of Representatives Committee on Government Reform Subcommittee on the Federal Workforce and Agency Organization Gregory H. Friedman: Before The U.S. House of ...
Gregory H. Friedman: Before the U.S. House of Representatives...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Gregory H. Friedman: Before the U.S. House of Representatives Committee on Energy and Commerce Subcommittee on Oversight and Investigations February 26, 2003 Before the U.S. House ...
4Q CY2003 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
Attached is the Facility Representative Program Performance Indicators (PIs) Quarterly Report Covering the Period from October to December 2003. Data for these indicators are gathered by Field...
3Q CY2003 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
Attached is the Facility Representative Program Performance Indicators (PIs) Quarterly Report Covering the Period from July to September 2003. Data for these indicators are gathered by Field...
2Q CY2003 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
Attached is the Facility Representative Program Performance Indicators (PIs) Quarterly Report Covering the Period from April to June 2003. Data for these indicators are gathered by Field elements...
1Q CY2003 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
Attached is the Facility Representative Program Performance Indicators (PIs) Quarterly Report Covering the Period from January to March 2003. Data for these indicators are gathered by Field...
2Q CY2004 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
Attached is the Facility Representative (FR) Program Performance Indicators Quarterly Report Covering the Period from April to June 2004. Data for these indicators are gathered by Field elements...
2Q CY2009 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Broader source: Energy.gov [DOE]
"Attached is the Facility Representative (FR) Program Performance Indicators Quarterly Report covering the period from April to June 2009. Data for these indicators are gathered by Field elements...
Properties of the Boltzmann equation in the classical approximation
Epelbaum, Thomas; Gelis, François; Tanji, Naoto; Wu, Bin
2014-12-30
We examine the Boltzmann equation with elastic point-like scalar interactions in two different versions of the the classical approximation. Although solving numerically the Boltzmann equation with the unapproximated collision term poses no problem, this allows one to study the effect of the ultraviolet cutoff in these approximations. This cutoff dependence in the classical approximations of the Boltzmann equation is closely related to the non-renormalizability of the classical statistical approximation of the underlying quantum field theory. The kinetic theory setup that we consider here allows one to study in a much simpler way the dependence on the ultraviolet cutoff, since one has also access to the non-approximated result for comparison.
Properties of the Boltzmann equation in the classical approximation
Tanji, Naoto; Epelbaum, Thomas; Gelis, Francois; Wu, Bin
2014-12-30
We study the Boltzmann equation with elastic point-like scalar interactions in two different versions of the the classical approximation. Although solving numerically the Boltzmann equation with the unapproximated collision term poses no problem, this allows one to study the effect of the ultraviolet cutoff in these approximations. This cutoff dependence in the classical approximations of the Boltzmann equation is closely related to the non-renormalizability of the classical statistical approximation of the underlying quantum field theory. The kinetic theory setup that we consider here allows one to study in a much simpler way the dependence on the ultraviolet cutoff, since one has also access to the non-approximated result for comparison.
Non-stochastic matrix Schrdinger equation for open systems
Joubert-Doriol, Loc; Ryabinkin, Ilya G.; Izmaylov, Artur F.
2014-12-21
We propose an extension of the Schrdinger equation for a quantum system interacting with environment. This extension describes dynamics of a collection of auxiliary wavefunctions organized as a matrix m, from which the system density matrix can be reconstructed as ?{sup ^}=mm{sup }. We formulate a compatibility condition, which ensures that the reconstructed density satisfies a given quantum master equation for the system density. The resulting non-stochastic evolution equation preserves positive-definiteness of the system density and is applicable to both Markovian and non-Markovian system-bath treatments. Our formalism also resolves a long-standing problem of energy loss in the time-dependent variational principle applied to mixed states of closed systems.
Properties of the Boltzmann equation in the classical approximation
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Epelbaum, Thomas; Gelis, François; Tanji, Naoto; Wu, Bin
2014-12-30
We examine the Boltzmann equation with elastic point-like scalar interactions in two different versions of the the classical approximation. Although solving numerically the Boltzmann equation with the unapproximated collision term poses no problem, this allows one to study the effect of the ultraviolet cutoff in these approximations. This cutoff dependence in the classical approximations of the Boltzmann equation is closely related to the non-renormalizability of the classical statistical approximation of the underlying quantum field theory. The kinetic theory setup that we consider here allows one to study in a much simpler way the dependence on the ultraviolet cutoff, since onemore » has also access to the non-approximated result for comparison.« less
Gregory H. Friedman: Before the U.S. House of Representatives Committee on
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Energy and Commerce Subcommittee on Oversight and Investigations | Department of Energy Energy and Commerce Subcommittee on Oversight and Investigations Gregory H. Friedman: Before the U.S. House of Representatives Committee on Energy and Commerce Subcommittee on Oversight and Investigations April 5, 2005 Before the U.S. House of Representatives Committee on Energy and Commerce Subcommittee on Oversight and Investigations Statement of Gregory H. Friedman, Inspector General U.S. Department of
Gregory H. Friedman: Before the U.S. House of Representatives Committee on
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Government Reform | Department of Energy Government Reform Gregory H. Friedman: Before the U.S. House of Representatives Committee on Government Reform March 20, 2003 Before the U.S. House of Representatives Committee on Government Reform Statement of Gregory H. Friedman Inspector General, U.S. Department of Energy Request to testify on the Department of Energy's (Department) contract administration activities. The Department is one of the most contractor dependent agencies in the Federal
W&M Student Elected to Represent American Physical Society's Graduate
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Student Forum | Jefferson Lab W&M Student Elected to Represent American Physical Society's Graduate Student Forum W&M Student Elected to Represent American Physical Society's Graduate Student Forum V Gray Valerie Gray, a graduate student at The College of William and Mary and a researcher at the Department of Energy's Thomas Jefferson National Accelerator Facility, was chosen this year by American Physical Society members as chair-elect for the APS Forum on Graduate Student Affairs.
Multi-time Schrdinger equations cannot contain interaction potentials
Petrat, Sren; Tumulka, Roderich
2014-03-15
Multi-time wave functions are wave functions that have a time variable for every particle, such as ?(t{sub 1},x{sub 1},...,t{sub N},x{sub N}). They arise as a relativistic analog of the wave functions of quantum mechanics but can be applied also in quantum field theory. The evolution of a wave function with N time variables is governed by N Schrdinger equations, one for each time variable. These Schrdinger equations can be inconsistent with each other, i.e., they can fail to possess a joint solution for every initial condition; in fact, the N Hamiltonians need to satisfy a certain commutator condition in order to be consistent. While this condition is automatically satisfied for non-interacting particles, it is a challenge to set up consistent multi-time equations with interaction. We prove for a wide class of multi-time Schrdinger equations that the presence of interaction potentials (given by multiplication operators) leads to inconsistency. We conclude that interaction has to be implemented instead by creation and annihilation of particles, which, in fact, can be done consistently [S. Petrat and R. Tumulka, Multi-time wave functions for quantum field theory, Ann. Physics (to be published)]. We also prove the following result: When a cut-off length ? > 0 is introduced (in the sense that the multi-time wave function is defined only on a certain set of spacelike configurations, thereby breaking Lorentz invariance), then the multi-time Schrdinger equations with interaction potentials of range ? are consistent; however, in the desired limit ? ? 0 of removing the cut-off, the resulting multi-time equations are interaction-free, which supports the conclusion expressed in the title.
Equation of State Measurements by Radiography Provide Evidence for a
Office of Scientific and Technical Information (OSTI)
Liquid-Liquid Phase Transition in Cerium (Journal Article) | SciTech Connect Equation of State Measurements by Radiography Provide Evidence for a Liquid-Liquid Phase Transition in Cerium Citation Details In-Document Search Title: Equation of State Measurements by Radiography Provide Evidence for a Liquid-Liquid Phase Transition in Cerium Authors: Lipp, M J ; Jenei, Z ; Ruddle, D ; Aracne-Ruddle, C ; Cynn, H ; Evans, W J ; Kono, Y ; Kenney-Benson, C ; Park, C Publication Date: 2013-08-26 OSTI
Equation of state measurements by radiography provide evidence for a
Office of Scientific and Technical Information (OSTI)
liquid-liquid phase transition in cerium (Journal Article) | SciTech Connect Equation of state measurements by radiography provide evidence for a liquid-liquid phase transition in cerium Citation Details In-Document Search Title: Equation of state measurements by radiography provide evidence for a liquid-liquid phase transition in cerium Authors: Lipp, M.J. ; Jenei, Zs. ; Ruddle, D. ; Aracne-Ruddle, C. ; Cynn, H. ; Evans, W.J. ; Kono, Y. ; Kenney-Benson, C. ; Park, C. [1] ; CIW) [2] + Show
Equations of state and phase diagrams of hydrogen isotopes
Urlin, V. D.
2013-11-15
A new form of the semiempirical equation of state proposed for the liquid phase of hydrogen isotopes is based on the assumption that its structure is formed by cells some of which contain hydrogen molecules and others contain hydrogen atoms. The values of parameters in the equations of state of the solid (molecular and atomic) phases as well as of the liquid phase of hydrogen isotopes (protium and deuterium) are determined. Phase diagrams, shock adiabats, isentropes, isotherms, and the electrical conductivity of compressed hydrogen are calculated. Comparison of the results of calculations with available experimental data in a wide pressure range demonstrates satisfactory coincidence.
Equation of State measurements of hydrogen isotopes on Nova
Collins, G. W., LLNL
1997-11-01
High intensity lasers can be used to perform measurements of materials at extremely high pressures if certain experimental issues can be overcome. We have addressed those issues and used the Nova laser to shock-compress liquid deuterium and obtain measurements of density and pressure on the principal Hugoniot at pressures from 300 kbar to more than 2 Mbar. The data are compared with a number of equation of state models. The data indicate that the effect of molecular dissociation of the deuterium into a monatomic phase may have a significant impact on the equation of state near 1 Mbar.
Ideal solar cell equation in the presence of photon recycling
Lan, Dongchen Green, Martin A.
2014-11-07
Previous derivations of the ideal solar cell equation based on Shockley's p-n junction diode theory implicitly assume negligible effects of photon recycling. This paper derives the equation in the presence of photon recycling that modifies the values of dark saturation and light-generated currents, using an approach applicable to arbitrary three-dimensional geometries with arbitrary doping profile and variable band gap. The work also corrects an error in previous work and proves the validity of the reciprocity theorem for charge collection in such a more general case with the previously neglected junction depletion region included.
Levinson theorem for the Dirac equation in D+1 dimensions
Gu Xiaoyan; Ma Zhongqi; Dong Shihai
2003-06-01
In terms of the generalized Sturm-Liouville theorem, the Levinson theorem for the Dirac equation with a spherically symmetric potential in D+1 dimensions is uniformly established as a relation between the total number of bound states and the sum of the phase shifts of the scattering states at E={+-}M with a given angular momentum. The critical case, where the Dirac equation has a half bound state, is analyzed in detail. A half bound state is a zero-momentum solution if its wave function is finite but does not decay fast enough at infinity to be square integrable.
Simplified P N Equations Steven P. Hamilton, Thomas M. Evans
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Efficient Solution of the Simplified P N Equations Steven P. Hamilton, Thomas M. Evans Oak Ridge National Laboratory December 29, 2014 CASL-U-2014-0352-000 Efficient solution of the simplified P N equations $ Steven P. Hamilton a,1,∗ , Thomas M. Evans a,1 a Oak Ridge National Laboratory, 1 Bethel Valley Rd., Oak Ridge, TN 37831 U.S.A. Abstract In this paper we show new solver strategies for the multigroup SP N equa- tions for nuclear reactor analysis. By forming the complete matrix over space,
Dirac equation in low dimensions: The factorization method
Snchez-Monroy, J.A.; Quimbay, C.J.
2014-11-15
We present a general approach to solve the (1+1) and (2+1)-dimensional Dirac equations in the presence of static scalar, pseudoscalar and gauge potentials, for the case in which the potentials have the same functional form and thus the factorization method can be applied. We show that the presence of electric potentials in the Dirac equation leads to two KleinGordon equations including an energy-dependent potential. We then generalize the factorization method for the case of energy-dependent Hamiltonians. Additionally, the shape invariance is generalized for a specific class of energy-dependent Hamiltonians. We also present a condition for the absence of the Klein paradox (stability of the Dirac sea), showing how Dirac particles in low dimensions can be confined for a wide family of potentials. - Highlights: The low-dimensional Dirac equation in the presence of static potentials is solved. The factorization method is generalized for energy-dependent Hamiltonians. The shape invariance is generalized for energy-dependent Hamiltonians. The stability of the Dirac sea is related to the existence of supersymmetric partner Hamiltonians.
Solves Poisson's Equation in Axizymmetric Geometry on a Rectangular Mesh
Energy Science and Technology Software Center (OSTI)
1996-09-10
DATHETA4.0 computes the magnetostatic field produced by multiple point current sources in the presence of perfect conductors in axisymmetric geometry. DATHETA4.0 has an interactive user interface and solves Poisson''s equation using the ADI method on a rectangular finite-difference mesh. DATHETA4.0 uncludes models specific to applied-B ion diodes.
Gravitational lens equation for embedded lenses; magnification and ellipticity
Chen, B.; Kantowski, R.; Dai, X.
2011-10-15
We give the lens equation for light deflections caused by point mass condensations in an otherwise spatially homogeneous and flat universe. We assume the signal from a distant source is deflected by a single condensation before it reaches the observer. We call this deflector an embedded lens because the deflecting mass is part of the mean density. The embedded lens equation differs from the conventional lens equation because the deflector mass is not simply an addition to the cosmic mean. We prescribe an iteration scheme to solve this new lens equation and use it to compare our results with standard linear lensing theory. We also compute analytic expressions for the lowest order corrections to image amplifications and distortions caused by incorporating the lensing mass into the mean. We use these results to estimate the effect of embedding on strong lensing magnifications and ellipticities and find only small effects, <1%, contrary to what we have found for time delays and for weak lensing, {approx}5%.
Topological horseshoes in travelling waves of discretized nonlinear wave equations
Chen, Yi-Chiuan; Chen, Shyan-Shiou; Yuan, Juan-Ming
2014-04-15
Applying the concept of anti-integrable limit to coupled map lattices originated from space-time discretized nonlinear wave equations, we show that there exist topological horseshoes in the phase space formed by the initial states of travelling wave solutions. In particular, the coupled map lattices display spatio-temporal chaos on the horseshoes.
National Lab Uses OGJ Data to Develop Cost Equations
Brown, Daryl R.; Cabe, James E.; Stout, Tyson E.
2011-01-03
For the past 30 years, the Oil and Gas Journal (OGJ) has published data on the costs of onshore and offshore oil and gas pipelines and related equipment. This article describes the methodology employed and resulting equations developed for conceptual capital cost estimating of onshore pipelines. Also described are cost trends uncovered during the course of the analysis.
Development of a One-Equation Transition/Turbulence Model
EDWARDS,JACK R.; ROY,CHRISTOPHER J.; BLOTTNER,FREDERICK G.; HASSAN,HASSAN A.
2000-09-26
This paper reports on the development of a unified one-equation model for the prediction of transitional and turbulent flows. An eddy viscosity - transport equation for non-turbulent fluctuation growth based on that proposed by Warren and Hassan (Journal of Aircraft, Vol. 35, No. 5) is combined with the Spalart-Allmaras one-equation model for turbulent fluctuation growth. Blending of the two equations is accomplished through a multidimensional intermittence function based on the work of Dhawan and Narasimha (Journal of Fluid Mechanics, Vol. 3, No. 4). The model predicts both the onset and extent of transition. Low-speed test cases include transitional flow over a flat plate, a single element airfoil, and a multi-element airfoil in landing configuration. High-speed test cases include transitional Mach 3.5 flow over a 5{degree} cone and Mach 6 flow over a flared-cone configuration. Results are compared with experimental data, and the spatial accuracy of selected predictions is analyzed.
U.S. Energy Secretary Steven Chu, U.S. Representatives Larson and Courtney
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
to Visit Research Center in East Hartford | Department of Energy Steven Chu, U.S. Representatives Larson and Courtney to Visit Research Center in East Hartford U.S. Energy Secretary Steven Chu, U.S. Representatives Larson and Courtney to Visit Research Center in East Hartford February 3, 2011 - 12:00am Addthis WASHINGTON, DC - Tomorrow, Friday, February 4, U.S. Secretary of Energy Steven Chu will travel to East Hartford, Conn. to visit United Technologies Research Center, which has received
WHAT THE SMART GRID MEANS TO YOU AND THE PEOPLE YOU REPRESENT. | Department
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
of Energy THE SMART GRID MEANS TO YOU AND THE PEOPLE YOU REPRESENT. WHAT THE SMART GRID MEANS TO YOU AND THE PEOPLE YOU REPRESENT. The U.S. Department of Energy (DOE) is charged under the Energy Independence and Security Act of 2007 (EISA 2007) with modernizing the nation's electricity grid to improve its reliability and efficiency. As part of this effort, DOE is also responsible for increasing awareness of our nation's Smart Grid. Building upon The Smart Grid: An Introduction, a
Edlund Named DOE Facility Representative of the Year | Y-12 National
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Security Complex Edlund Named DOE Facility ... Edlund Named DOE Facility Representative of the Year Posted: May 10, 2016 - 10:24am Jeff Edlund of the National Nuclear Security Administration Production Office was recently named Facility Representative of the Year by the U.S. Department of Energy. OAK RIDGE, Tenn. -- Jeff Edlund, who conducts day-to-day federal oversight of enriched uranium facility operations at the Y-12 National Security Complex, has been named the U.S. Department of Energy
Dy-Mn-Si as a representative of family of 'Dy-Transition
Office of Scientific and Technical Information (OSTI)
Metal-Si' systems: Its isothermal sections, empirical rProd. Type: FTPules and new rare-earth manganese silicides (Journal Article) | SciTech Connect Dy-Mn-Si as a representative of family of 'Dy-Transition Metal-Si' systems: Its isothermal sections, empirical rProd. Type: FTPules and new rare-earth manganese silicides Citation Details In-Document Search Title: Dy-Mn-Si as a representative of family of 'Dy-Transition Metal-Si' systems: Its isothermal sections, empirical rProd. Type: FTPules
DOE Honors WIPP Representative for Cutting Travel Costs, Greenhouse Gas Emissions
Broader source: Energy.gov [DOE]
WASHINGTON, D.C. – A representative of the Waste Isolation Pilot Plant (WIPP) near Carlsbad, N.M., on Tuesday received the Secretary of Energy’s Appreciation Award for her efforts to improve sustainability and reduce travel costs and the number of fleet vehicles.
Xu, Wei; Sun, Xin; Li, Dongsheng; Ryu, Seun; Khaleel, Mohammad A.
2013-02-01
Quantitative understanding of the evolving thermal-mechanical properties of a multi-phase material hinges upon the availability of quantitative statistically representative microstructure descriptions. Questions then arise as to whether a two-dimensional (2D) or a three-dimensional (3D) representative volume element (RVE) should be considered as the statistically representative microstructure. Although 3D models are more representative than 2D models in general, they are usually computationally expensive and difficult to be reconstructed. In this paper, we evaluate the accuracy of a 2D RVE in predicting the property degradations induced by different degradation mechanisms with the multiphase solid oxide fuel cell (SOFC) anode material as an example. Both 2D and 3D microstructure RVEs of the anodes are adopted to quantify the effects of two different degradation mechanisms: humidity-induced electrochemical degradation and phosphorus poisoning induced structural degradation. The predictions of the 2D model are then compared with the available experimental measurements and the results from the 3D model. It is found that the 2D model, limited by its inability of reproducing the realistic electrical percolation, is unable to accurately predict the degradation of thermo-electrical properties. On the other hand, for the phosphorus poisoning induced structural degradation, both 2D and 3D microstructures yield similar results, indicating that the 2D model is capable of providing computationally efficient yet accurate results for studying the structural degradation within the anodes.
Vorticity Preserving Flux Corrected Transport Scheme for the Acoustic Equations
Lung, Tyler B.; Roe, Phil; Morgan, Nathaniel R.
2012-08-15
Long term research goals are to develop an improved cell-centered Lagrangian Hydro algorithm with the following qualities: 1. Utilizes Flux Corrected Transport (FCT) to achieve second order accuracy with multidimensional physics; 2. Does not rely on the one-dimensional Riemann problem; and 3. Implements a form of vorticity control. Short term research goals are to devise and implement a 2D vorticity preserving FCT solver for the acoustic equations on an Eulerian mesh: 1. Develop a flux limiting mechanism for systems of governing equations with symmetric wave speeds; 2. Verify the vorticity preserving properties of the scheme; and 3. Compare the performance of the scheme to traditional MUSCL-Hancock and other algorithms.
Eternal inflation and a thermodynamic treatment of Einstein's equations
Ghersi, José Tomás Gálvez; Geshnizjani, Ghazal; Shandera, Sarah; Piazza, Federico E-mail: ggeshnizjani@perimeterinstitute.ca E-mail: sshandera@perimeterinstitute.ca
2011-06-01
In pursuing the intriguing resemblance of the Einstein equations to thermodynamic equations, most sharply seen in systems possessing horizons, we suggest that eternal inflation of the stochastic type may be a fruitful phenomenon to explore. We develop a thermodynamic first law for quasi-de Sitter space, valid on the horizon of a single observer's Hubble patch and explore consistancy with previous proposals for horizons of various types in dynamic and static situations. We use this framework to demonstrate that for the local observer fluctuations of the type necessary for stochastic eternal inflation fall within the regime where the thermodynamic approach is believed to apply. This scenario is interesting because of suggestive parallels with black hole evaporation.
Numerical solution of three-dimensional magnetic differential equations
Reiman, A.H.; Greenside, H.S.
1987-02-01
A computer code is described that solves differential equations of the form B . del f = h for a single-valued solution f, given a toroidal three-dimensional divergence-free field B and a single-valued function h. The code uses a new algorithm that Fourier decomposes a given function in a set of flux coordinates in which the field lines are straight. The algorithm automatically adjusts the required integration lengths to compensate for proximity to low order rational surfaces. Applying this algorithm to the Cartesian coordinates defines a transformation to magnetic coordinates, in which the magnetic differential equation can be accurately solved. Our method is illustrated by calculating the Pfirsch-Schlueter currents for a stellarator.
Quantum Markovian master equation for scattering from surfaces
Li, Haifeng; Shao, Jiushu; Azuri, Asaf; Pollak, Eli Alicki, Robert
2014-01-07
We propose a semi-phenomenological Markovian Master equation for describing the quantum dynamics of atom-surface scattering. It embodies the Lindblad-like structure and can describe both damping and pumping of energy between the system and the bath. It preserves positivity and correctly accounts for the vanishing of the interaction of the particle with the surface when the particle is distant from the surface. As a numerical test, we apply it to a model of an Ar atom scattered from a LiF surface, allowing for interaction only in the vertical direction. At low temperatures, we find that the quantum mechanical average energy loss is smaller than the classical energy loss. The numerical results obtained from the space dependent friction master equation are compared with numerical simulations for a discretized bath, using the multi-configurational time dependent Hartree methodology. The agreement between the two simulations is quantitative.
Higher order matrix differential equations with singular coefficient matrices
Fragkoulis, V. C.; Kougioumtzoglou, I. A.; Pantelous, A. A.; Pirrotta, A.
2015-03-10
In this article, the class of higher order linear matrix differential equations with constant coefficient matrices and stochastic process terms is studied. The coefficient of the highest order is considered to be singular; thus, rendering the response determination of such systems in a straightforward manner a difficult task. In this regard, the notion of the generalized inverse of a singular matrix is used for determining response statistics. Further, an application relevant to engineering dynamics problems is included.
Scientists compose complex math equations to replicate behaviors of Earth
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systems | Argonne National Laboratory Rob Jacob talks about climate models Climate Models: Rob Jacob Scientists compose complex math equations to replicate behaviors of Earth systems By Angela Hardin * December 16, 2015 Tweet EmailPrint Whenever news breaks about what Earth's climate is expected to be like decades into the future or how much rainfall various regions around the country or the world are likely to receive, those educated estimates are generated by a global climate model. But
Method of comparison equations for Schwarzschild black holes
Casadio, Roberto; Luzzi, Mattia
2006-10-15
We employ the method of comparison equations to study the propagation of a massless minimally coupled scalar field on the Schwarzschild background. In particular, we show that this method allows us to obtain explicit approximate expressions for the radial modes with energy below the peak of the effective potential which are fairly accurate over the whole region outside the horizon. This case can be of particular interest, for example, for the problem of black hole evaporation.
Time-periodic solutions of the Benjamin-Ono equation
Ambrose , D.M.; Wilkening, Jon
2008-04-01
We present a spectrally accurate numerical method for finding non-trivial time-periodic solutions of non-linear partial differential equations. The method is based on minimizing a functional (of the initial condition and the period) that is positive unless the solution is periodic, in which case it is zero. We solve an adjoint PDE to compute the gradient of this functional with respect to the initial condition. We include additional terms in the functional to specify the free parameters, which, in the case of the Benjamin-Ono equation, are the mean, a spatial phase, a temporal phase and the real part of one of the Fourier modes at t = 0. We use our method to study global paths of non-trivial time-periodic solutions connecting stationary and traveling waves of the Benjamin-Ono equation. As a starting guess for each path, we compute periodic solutions of the linearized problem by solving an infinite dimensional eigenvalue problem in closed form. We then use our numerical method to continue these solutions beyond the realm of linear theory until another traveling wave is reached (or until the solution blows up). By experimentation with data fitting, we identify the analytical form of the solutions on the path connecting the one-hump stationary solution to the two-hump traveling wave. We then derive exact formulas for these solutions by explicitly solving the system of ODE's governing the evolution of solitons using the ansatz suggested by the numerical simulations.
Reconsidering harmonic and anharmonic coherent states: Partial differential equations approach
Toutounji, Mohamad
2015-02-15
This article presents a new approach to dealing with time dependent quantities such as autocorrelation function of harmonic and anharmonic systems using coherent states and partial differential equations. The approach that is normally used to evaluate dynamical quantities involves formidable operator algebra. That operator algebra becomes insurmountable when employing Morse oscillator coherent states. This problem becomes even more complicated in case of Morse oscillator as it tends to exhibit divergent dynamics. This approach employs linear partial differential equations, some of which may be solved exactly and analytically, thereby avoiding the cumbersome noncommutative algebra required to manipulate coherent states of Morse oscillator. Additionally, the arising integrals while using the herein presented method feature stability and high numerical efficiency. The correctness, applicability, and utility of the above approach are tested by reproducing the partition and optical autocorrelation function of the harmonic oscillator. A closed-form expression for the equilibrium canonical partition function of the Morse oscillator is derived using its coherent states and partial differential equations. Also, a nonequilibrium autocorrelation function expression for weak electron–phonon coupling in condensed systems is derived for displaced Morse oscillator in electronic state. Finally, the utility of the method is demonstrated through further simplifying the Morse oscillator partition function or autocorrelation function expressions reported by other researchers in unevaluated form of second-order derivative exponential. Comparison with exact dynamics shows identical results.
WHAT THE SMART GRID MEANS TO YOU AND THE PEOPLE YOU REPRESENT.
REPRESENT. regulators consumer advocates environmental groups technology providers policymakers ONE of SIX SMART GRID STAKEHOLDER BOOKS A smarter grid can work harder and more efficiently to respond to the needs of all consumers, contain costs and enable clean-energy solutions at scale. regulators utilities 2 DISCLAIMER PRINTED IN THE UNITED STATES OF AMERICA. This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States
On October 20, 2011, representatives of Howe Corporation, Gade Environmental, an
October 20, 2011, representatives of Howe Corporation, Gade Environmental, and Beecon ProfServe met with DOE to discuss the proposed rules EERE-2010 BT-TP-0036 RIN 1904-AC38 Energy Efficiency Program for Certain Commercial and Industrial Equipment: Test Procedures for Commercial Ice Makers. The meeting was held at the request of Howe Corporation at the DOE offices in Washington DC. In attendance: Ari Altman, DOE Ashley Armstrong, DOE Robert Bittner, Beecon ProfServe John Cymbalsky, DOE Mary
Polytechnic Institute of New York University Researchers Represented in the E-print Network
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EDUconnections Spotlight Polytechnic Institute of New York University Researchers Represented in the E-print Network Researcher/Research Institution Web page Aronov, Boris - Department of Computer Science and Engineering, Polytechnic Institute of New York University http://cis.poly.edu/~aronov/research. html Brönnimann, Hervé - Department of Computer Science and Engineering, Polytechnic Institute of New York University http://photon.poly.edu/~hbr/publis. html Chiang, Yi-Jen - Department of
100% MOX BWR experimental program design using multi-parameter representative
Blaise, P.; Fougeras, P.; Cathalau, S.
2012-07-01
A new multiparameter representative approach for the design of Advanced full MOX BWR core physics experimental programs is developed. The approach is based on sensitivity analysis of integral parameters to nuclear data, and correlations among different integral parameters. The representativeness method is here used to extract a quantitative relationship between a particular integral response of an experimental mock-up and the same response in a reference project to be designed. The study is applied to the design of the 100% MOX BASALA ABWR experimental program in the EOLE facility. The adopted scheme proposes an original approach to the problem, going from the initial 'microscopic' pin-cells integral parameters to the whole 'macroscopic' assembly integral parameters. This approach enables to collect complementary information necessary to optimize the initial design and to meet target accuracy on the integral parameters to be measured. The study has demonstrated the necessity of new fuel pins fabrication, fulfilling minimal costs requirements, to meet acceptable representativeness on local power distribution. (authors)
Charles Laverty
2005-10-01
UNIPROCESSOR PERFORMANCE ANALYSIS OF A REPRESENTATIVE WORKLOAD OF SANDIA NATIONAL LABORATORIES' SCIENTIFIC APPLICATIONS Master of Science in Electrical Engineering New Mexico State University Las Cruces, New Mexico, 2005 Dr. Jeanine Cook, Chair Throughout the last decade computer performance analysis has become absolutely necessary to maximum performance of some workloads. Sandia National Laboratories (SNL) located in Albuquerque, New Mexico is no different in that to achieve maximum performance of large scientific, parallel workloads performance analysis is needed at the uni-processor level. A representative workload has been chosen as the basis of a computer performance study to determine optimal processor characteristics in order to better specify the next generation of supercomputers. Cube3, a finite element test problem developed at SNL is a representative workload of their scientific workloads. This workload has been studied at the uni-processor level to understand characteristics in the microarchitecture that will lead to the overall performance improvement at the multi-processor level. The goal of studying vthis workload at the uni-processor level is to build a performance prediction model that will be integrated into a multi-processor performance model which is currently being developed at SNL. Through the use of performance counters on the Itanium 2 microarchitecture, performance statistics are studied to determine bottlenecks in the microarchitecture and/or changes in the application code that will maximize performance. From source code analysis a performance degrading loop kernel was identified and through the use of compiler optimizations a performance gain of around 20% was achieved.
Development and Application of Compatible Discretizations of Maxwell's Equations
White, D; Koning, J; Rieben, R
2005-05-27
We present the development and application of compatible finite element discretizations of electromagnetics problems derived from the time dependent, full wave Maxwell equations. We review the H(curl)-conforming finite element method, using the concepts and notations of differential forms as a theoretical framework. We chose this approach because it can handle complex geometries, it is free of spurious modes, it is numerically stable without the need for filtering or artificial diffusion, it correctly models the discontinuity of fields across material boundaries, and it can be very high order. Higher-order H(curl) and H(div) conforming basis functions are not unique and we have designed an extensible C++ framework that supports a variety of specific instantiations of these such as standard interpolatory bases, spectral bases, hierarchical bases, and semi-orthogonal bases. Virtually any electromagnetics problem that can be cast in the language of differential forms can be solved using our framework. For time dependent problems a method-of-lines scheme is used where the Galerkin method reduces the PDE to a semi-discrete system of ODE's, which are then integrated in time using finite difference methods. For time integration of wave equations we employ the unconditionally stable implicit Newmark-Beta method, as well as the high order energy conserving explicit Maxwell Symplectic method; for diffusion equations, we employ a generalized Crank-Nicholson method. We conclude with computational examples from resonant cavity problems, time-dependent wave propagation problems, and transient eddy current problems, all obtained using the authors massively parallel computational electromagnetics code EMSolve.
Real-time nonlinear optimization as a generalized equation.
Zavala, V. M.; Anitescu, M. (Mathematics and Computer Science)
2010-11-11
We establish results for the problem of tracking a time-dependent manifold arising in real-time optimization by casting this as a parametric generalized equation. We demonstrate that if points along a solution manifold are consistently strongly regular, it is possible to track the manifold approximately by solving a single linear complementarity problem (LCP) at each time step. We derive sufficient conditions guaranteeing that the tracking error remains bounded to second order with the size of the time step even if the LCP is solved only approximately. We use these results to derive a fast, augmented Lagrangian tracking algorithm and demonstrate the developments through a numerical case study.
Heart simulation with surface equations for using on MCNP code
Rezaei-Ochbelagh, D.; Salman-Nezhad, S.; Asadi, A.; Rahimi, A.
2011-12-26
External photon beam radiotherapy is carried out in a way to achieve an 'as low as possible' a dose in healthy tissues surrounding the target. One of these surroundings can be heart as a vital organ of body. As it is impossible to directly determine the absorbed dose by heart, using phantoms is one way to acquire information around it. The other way is Monte Carlo method. In this work we have presented a simulation of heart geometry by introducing of different surfaces in MCNP code. We used 14 surface equations in order to determine human heart modeling. Those surfaces are borders of heart walls and contents.
CDF Solutions of Buckley-Leverett Equation with Uncertain Parameters
Wang, Peng; Tartakovsky, Daniel M.; Jarman, Kenneth D.; Tartakovsky, Alexandre M.
2013-01-15
The Buckley-Leverett (nonlinear advection) equation is often used to describe two-phase flow in porous media. We develop a new probabilistic method to quantify parametric uncertainty in the Buckley-Leverett model. Our approach is based on the concept of fine-grained cumulative density function (CDF) and provides a full statistical description of the system states. Hence, it enables one to obtain not only average system response but also the probability of rare events, which is critical for risk assessment. We obtain a closed-form, semi-analytical solution and test it against the results from Monte Carlo simulations.
Fire Intensity Data for Validation of the Radiative Transfer Equation
Blanchat, Thomas K.; Jernigan, Dann A.
2016-01-01
A set of experiments and test data are outlined in this report that provides radiation intensity data for the validation of models for the radiative transfer equation. The experiments were performed with lightly-sooting liquid hydrocarbon fuels that yielded fully turbulent fires 2 m diameter). In addition, supplemental measurements of air flow and temperature, fuel temperature and burn rate, and flame surface emissive power, wall heat, and flame height and width provide a complete set of boundary condition data needed for validation of models used in fire simulations.
The Equation of State of LLM-105 (2,6-diamino-3,5-dinitropyrazine...
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The Equation of State of LLM-105 (2,6-diamino-3,5-dinitropyrazine-1-oxide) Citation Details In-Document Search Title: The Equation of State of LLM-105 (2,6-diamino-3,5-dinitropyraz...
Thermal equation of state and stability of (Mg[subscript 0.06...
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Thermal equation of state and stability of (Mgsubscript 0.06Fesubscript 0.94)O Citation Details In-Document Search Title: Thermal equation of state and stability of ...
Synthesis and equation of state of perovskite in the (Mg,Fe)...
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Synthesis and equation of state of perovskite in the (Mg,Fe)subscript 3Alsubscript ... Citation Details In-Document Search Title: Synthesis and equation of state of perovskite ...
Equations of state in the Fe-FeSi system at high pressures and...
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Equations of state in the Fe-FeSi system at high pressures and temperatures Citation Details In-Document Search Title: Equations of state in the Fe-FeSi system at high pressures ...
Wong's equations and the small x effective action in QCD (Journal...
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Wong's equations and the small x effective action in QCD Citation Details In-Document Search Title: Wong's equations and the small x effective action in QCD We propose a new form ...
A new high pressure and temperature equation of state of fcc...
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new high pressure and temperature equation of state of fcc cobalt Citation Details In-Document Search Title: A new high pressure and temperature equation of state of fcc cobalt ...
Phase Diagram and Equation of State of Magnesium to High Pressures...
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Phase Diagram and Equation of State of Magnesium to High Pressures and High Temperatures Citation Details In-Document Search Title: Phase Diagram and Equation of State of Magnesium ...
Broader source: Energy.gov [DOE]
A recent review of the January 2009 issue of the Department of Energy (DOE) Acquisition Career Management Program (ACMP) Handbook identified many areas that require an update. Although the ACMP Handbook revisions are underway, the Office of Management and Budget (OMB), Office of Federal Procurement Policy (OFPP) issued OFPP Memorandum, “Revisions to the Federal Acquisition Certification for Contracting Officer’s Representatives (FAC-COR),” dated September 6, 2011. This OFPP Memorandum requires that agencies implement the revised FAC-COR certifications effective January 1, 2012.
A general encoding framework for representing network measurement and topology data
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CONCURRENCY AND COMPUTATION: PRACTICE AND EXPERIENCE Concurrency Computat.: Pract. Exper. 2009; 21:1069-1086 Published online 11 February 2009 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/cpe.1412 A general encoding framework for representing network measurement and topology data A. Brown 1, ∗, † , M. Swany 1 and J. Zurawski 2 1 Department of Computer and Information Sciences, 103 Smith Hall, Newark, DE 19716, U.S.A. 2 Internet2, 1150 18th Street NW, Suite 1020,
Sampling device for withdrawing a representative sample from single and multi-phase flows
Apley, Walter J. (Pasco, WA); Cliff, William C. (Richland, WA); Creer, James M. (Richland, WA)
1984-01-01
A fluid stream sampling device has been developed for the purpose of obtaining a representative sample from a single or multi-phase fluid flow. This objective is carried out by means of a probe which may be inserted into the fluid stream. Individual samples are withdrawn from the fluid flow by sampling ports with particular spacings, and the sampling parts are coupled to various analytical systems for characterization of the physical, thermal, and chemical properties of the fluid flow as a whole and also individually.
Higher-order Schrödinger and Hartree–Fock equations
Carles, Rémi; Lucha, Wolfgang; Moulay, Emmanuel
2015-12-15
The domain of validity of the higher-order Schrödinger equations is analyzed for harmonic-oscillator and Coulomb potentials as typical examples. Then, the Cauchy theory for higher-order Hartree–Fock equations with bounded and Coulomb potentials is developed. Finally, the existence of associated ground states for the odd-order equations is proved. This renders these quantum equations relevant for physics.
Luo Yousong
2010-06-15
In this paper we derive a necessary optimality condition for a local optimal solution of some control problems. These optimal control problems are governed by a semi-linear Vettsel boundary value problem of a linear elliptic equation. The control is applied to the state equation via the boundary and a functional of the control together with the solution of the state equation under such a control will be minimized. A constraint on the solution of the state equation is also considered.
Thermodynamics of the polaron master equation at finite bias
Krause, Thilo Brandes, Tobias; Schaller, Gernot; Esposito, Massimiliano
2015-04-07
We study coherent transport through a double quantum dot. Its two electronic leads induce electronic matter and energy transport and a phonon reservoir contributes further energy exchanges. By treating the system-lead couplings perturbatively, whereas the coupling to vibrations is treated non-perturbatively in a polaron-transformed frame, we derive a thermodynamic consistent low-dimensional master equation. When the number of phonon modes is finite, a Markovian description is only possible when these couple symmetrically to both quantum dots. For a continuum of phonon modes however, also asymmetric couplings can be described with a Markovian master equation. We compute the electronic current and dephasing rate. The electronic current enables transport spectroscopy of the phonon frequency and displays signatures of Franck-Condon blockade. For infinite external bias but finite tunneling bandwidths, we find oscillations in the current as a function of the internal bias due to the electron-phonon coupling. Furthermore, we derive the full fluctuation theorem and show its identity to the entropy production in the system.
Possible ambiguities in the equation of state for neutron stars
Cheoun, Myung-Ki; Miyatsu, Tsuyoshi; Ryu, C. Y.; Deliduman, Cemsinan; Gngr, Can; Kele?, Vildan; Kajino, Toshitaka; Mathews, Grant J.
2014-05-02
We addressed possible ambiguities on the properties of neutron stars (NSs) estimated in theoretical sides. First, roles of hyperons inside the NS are discussed through various relativistic mean field (RMF) theories. In particular, the extension of SU(6) spin-flavor symmetry to SU(3) flavor symmetry is shown to give rise to the increase of hyperon threshold density, similarly to the Fock term effects in RMF theories. As a result, about 2.0 solar mass is obtained with the hyperons. Second, the effect by the modified f(R) gravity, which leaves a room for the dark energy in the Einstein equation to be taken into account, is discussed for the NS in a strong magnetic field (MF). Our results show that the modified gravity with the Kaluza-Klein electro-magnetism theory expanded in terms of a length scale parameter may reasonably describe the NS in strong MF, so called magnetar. Even the super-soft equation of state is shown to be revived by the modified f(R) gravity.
Nonparametric reconstruction of the dark energy equation of state
Heitmann, Katrin; Holsclaw, Tracy; Alam, Ujjaini; Habib, Salman; Higdon, David; Sanso, Bruno; Lee, Herbie
2009-01-01
The major aim of ongoing and upcoming cosmological surveys is to unravel the nature of dark energy. In the absence of a compelling theory to test, a natural approach is to first attempt to characterize the nature of dark energy in detail, the hope being that this will lead to clues about the underlying fundamental theory. A major target in this characterization is the determination of the dynamical properties of the dark energy equation of state w. The discovery of a time variation in w(z) could then lead to insights about the dynamical origin of dark energy. This approach requires a robust and bias-free method for reconstructing w(z) from data, which does not rely on restrictive expansion schemes or assumed functional forms for w(z). We present a new non parametric reconstruction method for the dark energy equation of state based on Gaussian Process models. This method reliably captures nontrivial behavior of w(z) and provides controlled error bounds. We demollstrate the power of the method on different sets of simulated supernova data. The GP model approach is very easily extended to include diverse cosmological probes.
Tanimura, Yoshitaka
2014-07-28
For a system strongly coupled to a heat bath, the quantum coherence of the system and the heat bath plays an important role in the system dynamics. This is particularly true in the case of non-Markovian noise. We rigorously investigate the influence of system-bath coherence by deriving the reduced hierarchal equations of motion (HEOM), not only in real time, but also in imaginary time, which represents an inverse temperature. It is shown that the HEOM in real time obtained when we include the system-bath coherence of the initial thermal equilibrium state possess the same form as those obtained from a factorized initial state. We find that the difference in behavior of systems treated in these two manners results from the difference in initial conditions of the HEOM elements, which are defined in path integral form. We also derive HEOM along the imaginary time path to obtain the thermal equilibrium state of a system strongly coupled to a non-Markovian bath. Then, we show that the steady state hierarchy elements calculated from the real-time HEOM can be expressed in terms of the hierarchy elements calculated from the imaginary-time HEOM. Moreover, we find that the imaginary-time HEOM allow us to evaluate a number of thermodynamic variables, including the free energy, entropy, internal energy, heat capacity, and susceptibility. The expectation values of the system energy and system-bath interaction energy in the thermal equilibrium state are also evaluated.
Dupont, Virginie; Germann, Timothy C
2011-01-18
Shock compression of materials constitutes a complex process involving high strain rates, elevated temperatures and compression of the lattice. Materials properties are greatly affected by temperature, the representative length scale and the strain rate of the deformation. Experimentally, it is difficult to study the dynamic microscopic mechanisms that affect materials properties following high intensity shock loading, but they can be investigated using molecular dynamics (MD) simulations. Moreover, MD allows a better control over some parameters. We are using MD simulations to study the effect of the strain rate, representative length scale and temperature on the properties of metals during compression. A half-million-atom Cu sample is subjected to strain rates ranging from 10{sup 7} s{sup -1} to 10{sup 12} s{sup -1} at different temperatures ranging from 50K to 1500K. Single crystals as well as polycrystals are investigated. Plasticity mechanisms as well as the evolution of the micro- and macro-yield stress are observed. Our results show that the yield stress increases with increasing strain rate and decreasing temperature. We also show that the strain rate at which the transition between constant and increasing yield stress as a function of the temperature occurs increases with increasing temperature. Calculations at different grain sizes will give an insight into the grain size effect on the plasticity mechanisms and the yield stress.
An estimated 5% of new protein structures solved today represent a new Pfam family
Mistry, Jaina; Kloppmann, Edda; Rost, Burkhard; Punta, Marco
2013-11-01
This study uses the Pfam database to show that the sequence redundancy of protein structures deposited in the PDB is increasing. The possible reasons behind this trend are discussed. High-resolution structural knowledge is key to understanding how proteins function at the molecular level. The number of entries in the Protein Data Bank (PDB), the repository of all publicly available protein structures, continues to increase, with more than 8000 structures released in 2012 alone. The authors of this article have studied how structural coverage of the protein-sequence space has changed over time by monitoring the number of Pfam families that acquired their first representative structure each year from 1976 to 2012. Twenty years ago, for every 100 new PDB entries released, an estimated 20 Pfam families acquired their first structure. By 2012, this decreased to only about five families per 100 structures. The reasons behind the slower pace at which previously uncharacterized families are being structurally covered were investigated. It was found that although more than 50% of current Pfam families are still without a structural representative, this set is enriched in families that are small, functionally uncharacterized or rich in problem features such as intrinsically disordered and transmembrane regions. While these are important constraints, the reasons why it may not yet be time to give up the pursuit of a targeted but more comprehensive structural coverage of the protein-sequence space are discussed.
On a hierarchy of nonlinearly dispersive generalized Korteweg - de Vries evolution equations
Christov, Ivan C.
2015-08-20
We propose a hierarchy of nonlinearly dispersive generalized Kortewegde Vries (KdV) evolution equations based on a modification of the Lagrangian density whose induced action functional the KdV equation extremizes. Two recent nonlinear evolution equations describing wave propagation in certain generalized continua with an inherent material length scale are members of the proposed hierarchy. Like KdV, the equations from the proposed hierarchy possess Hamiltonian structure. Unlike KdV, the solutions to these equations can be compact (i.e., they vanish outside of some open interval) and, in addition, peaked. Implicit solutions for these peaked, compact traveling waves (peakompactons) are presented.
On a hierarchy of nonlinearly dispersive generalized Korteweg - de Vries evolution equations
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Christov, Ivan C.
2015-08-20
We propose a hierarchy of nonlinearly dispersive generalized Korteweg–de Vries (KdV) evolution equations based on a modification of the Lagrangian density whose induced action functional the KdV equation extremizes. Two recent nonlinear evolution equations describing wave propagation in certain generalized continua with an inherent material length scale are members of the proposed hierarchy. Like KdV, the equations from the proposed hierarchy possess Hamiltonian structure. Unlike KdV, the solutions to these equations can be compact (i.e., they vanish outside of some open interval) and, in addition, peaked. Implicit solutions for these peaked, compact traveling waves (“peakompactons”) are presented.
Equation of State for Supercooled Water at Pressures up to 400 MPa
Holten, Vincent; Sengers, Jan V.; Anisimov, Mikhail A.
2014-12-01
An equation of state is presented for the thermodynamic properties of cold and supercooled water. It is valid for temperatures from the homogeneous ice nucleation temperature up to 300 K and for pressures up to 400 MPa, and can be extrapolated up to 1000 MPa. The equation of state is compared with experimental data for the density, expansion coefficient, isothermal compressibility, speed of sound, and heat capacity. Estimates for the accuracy of the equation are given. The melting curve of ice I is calculated from the phase-equilibrium condition between the proposed equation and an existing equation of state for ice I.
INTERACTING QUARK MATTER EQUATION OF STATE FOR COMPACT STARS
Fraga, Eduardo S.; Kurkela, Aleksi; Vuorinen, Aleksi
2014-02-01
Lattice quantum chromodynamics (QCD) studies of the thermodynamics of hot quark-gluon plasma demonstrate the importance of accounting for the interactions of quarks and gluons if one wants to investigate the phase structure of strongly interacting matter. Motivated by this observation and using state-of-the-art results from perturbative QCD, we construct a simple, effective equation of state (EOS) for cold quark matter that consistently incorporates the effects of interactions and furthermore includes a built-in estimate of the inherent systematic uncertainties. This goes beyond the MIT bag model description in a crucial way, yet leads to an EOS that is equally straightforward to use. We also demonstrate that, at moderate densities, our EOS can be made to smoothly connect to hadronic EOSs, with the two exhibiting very similar behavior near the matching region. The resulting hybrid stars are seen to have masses similar to those predicted by the purely nucleonic EOSs.
The isobaric multiplet mass equation for A?71 revisited
Lam, Yi Hua; Blank, Bertram; Smirnova, Nadezda A.; Bueb, Jean Bernard; Antony, Maria Susai
2013-11-15
Accurate mass determination of short-lived nuclides by Penning-trap spectrometers and progress in the spectroscopy of proton-rich nuclei have triggered renewed interest in the isobaric multiplet mass equation (IMME). The energy levels of the members of T=1/2,1,3/2, and 2 multiplets and the coefficients of the IMME are tabulated for A?71. The new compilation is based on the most recent mass evaluation (AME2011) and it includes the experimental results on energies of the states evaluated up to end of 2011. Taking into account the error bars, a significant deviation from the quadratic form of the IMME for the A=9,35 quartets and the A=32 quintet is observed.
Levinson theorem for the Dirac equation in one dimension
Ma Zhongqi; Dong Shihai; Wang Luya
2006-07-15
The Levinson theorem for the (1+1)-dimensional Dirac equation with a symmetric potential is proved with the Sturm-Liouville theorem. The half-bound states at the energies E={+-}M, whose wave function is finite but does not decay at infinity fast enough to be square integrable, are discussed. The number n{sub {+-}} of bound states is equal to the sum of the phase shifts at the energies E={+-}M:{delta}{sub {+-}}(M)+{delta}{sub {+-}}(-M)=(n{sub {+-}}+a){pi}, where the subscript {+-} denotes the parity and the constant a is equal to -1/2 when no half-bound state occurs, to 0 when one half-bound state occurs at E=M or at E=-M, and to 1/2 when two half-bound states occur at both E={+-}M.
SESAME 7363: A new Li(6)D equation of state
Sheppard, Daniel Glen; Kress, Joel David; Crockett, Scott; Collins, Lee A.; Greeff, Carl William
2015-09-21
A new Equation of State (EOS) for Lithium 6 Deuteride (^{6}LiD) was created, sesame 7363. This EOS was released to the user community under “eos-developmental” as sesame 97363. The construction of this new EOS is a modification of a previously released EOS, sesame 7360^{1}. Sesame 7360 is too stiff (5-10% excess pressure) at high compressions and high temperatures (ρ = 4-110g/cm^{3}, T = 30-10,000 eV) compared to orbital-free density-functional theory. Sesame 7363 is softer and gives a better representation of the physics over this range without compromising the agreement with the experimental and simulation data that sesame 7360 was based on.
Polynomial solutions of the Monge-Ampre equation
Aminov, Yu A
2014-11-30
The question of the existence of polynomial solutions to the Monge-Ampre equation z{sub xx}z{sub yy}?z{sub xy}{sup 2}=f(x,y) is considered in the case when f(x,y) is apolynomial. It is proved that if f is apolynomial of the second degree, which is positive for all values of its arguments and has apositive squared part, then no polynomial solution exists. On the other hand, asolution which is not polynomial but is analytic in the whole of the x,y-plane is produced. Necessary and sufficient conditions for the existence of polynomial solutions of degree up to 4 are found and methods for the construction of such solutions are indicated. An approximation theorem is proved. Bibliography: 10 titles.
Vapor-liquid equilibria for an R134a/lubricant mixture: Measurements and equation-of-state modeling
Huber, M.L.; Holcomb, C.D.; Outcalt, S.L.; Elliott, J.R.
2000-07-01
The authors measured bubble point pressures and coexisting liquid densities for two mixtures of R-134a and a polyolester (POE) lubricant. The mass fraction of the lubricant was approximately 9% and 12%, and the temperature ranged from 280 K to 355 K. The authors used the Elliott, Suresh, and Donohue (ESD) equation of state to model the bubble point pressure data. The bubble point pressures were represented with an average absolute deviation of 2.5%. A binary interaction parameter reduced the deviation to 1.4%. The authors also applied the ESD model to other R-134a/POE lubricant data in the literature. As the concentration of the lubricant increased, the performance of the model deteriorated markedly. However, the use of a single binary interaction parameter reduced the deviations significantly.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Zhao, Renjie; Evans, James W.; Oliveira, Tiago J.
2016-04-08
Here, a discrete version of deposition-diffusion equations appropriate for description of step flow on a vicinal surface is analyzed for a two-dimensional grid of adsorption sites representing the stepped surface and explicitly incorporating kinks along the step edges. Model energetics and kinetics appropriately account for binding of adatoms at steps and kinks, distinct terrace and edge diffusion rates, and possible additional barriers for attachment to steps. Analysis of adatom attachment fluxes as well as limiting values of adatom densities at step edges for nonuniform deposition scenarios allows determination of both permeability and kinetic coefficients. Behavior of these quantities is assessedmore » as a function of key system parameters including kink density, step attachment barriers, and the step edge diffusion rate.« less
A Subbasin-based framework to represent land surface processes in an Earth System Model
Tesfa, Teklu K.; Li, Hongyi; Leung, Lai-Yung R.; Huang, Maoyi; Ke, Yinghai; Sun, Yu; Liu, Ying
2014-05-20
Realistically representing spatial heterogeneity and lateral land surface processes within and between modeling units in earth system models is important because of their implications to surface energy and water exchange. The traditional approach of using regular grids as computational units in land surface models and earth system models may lead to inadequate representation of lateral movements of water, energy and carbon fluxes, especially when the grid resolution increases. Here a new subbasin-based framework is introduced in the Community Land Model (CLM), which is the land component of the Community Earth System Model (CESM). Local processes are represented assuming each subbasin as a grid cell on a pseudo grid matrix with no significant modifications to the existing CLM modeling structure. Lateral routing of water within and between subbasins is simulated with the subbasin version of a recently-developed physically based routing model, Model for Scale Adaptive River Routing (MOSART). As an illustration, this new framework is implemented in the topographically diverse region of the U.S. Pacific Northwest. The modeling units (subbasins) are delineated from high-resolution Digital Elevation Model while atmospheric forcing and surface parameters are remapped from the corresponding high resolution datasets. The impacts of this representation on simulating hydrologic processes are explored by comparing it with the default (grid-based) CLM representation. In addition, the effects of DEM resolution on parameterizing topography and the subsequent effects on runoff processes are investigated. Limited model evaluation and comparison showed that small difference between the averaged forcing can lead to more significant difference in the simulated runoff and streamflow because of nonlinear horizontal processes. Topographic indices derived from high resolution DEM may not improve the overall water balance, but affect the partitioning between surface and subsurface runoff. More systematic analyses are needed to determine the relative merits of the subbasin representation compared to the commonly used grid-based representation, especially when land surface models are approaching higher resolutions.
The one-dimensional Gross-Pitaevskii equation and its some excitation states
Prayitno, T. B.
2015-04-16
We have derived some excitation states of the one-dimensional Gross-Pitaevskii equation coupled by the gravitational potential. The methods that we have used here are taken by pursuing the recent work of Kivshar et. al. by considering the equation as a macroscopic quantum oscillator. To obtain the states, we have made the appropriate transformation to reduce the three-dimensional Gross-Pitaevskii equation into the one-dimensional Gross-Pitaevskii equation and applying the time-independent perturbation theory in the general solution of the one-dimensional Gross-Pitaevskii equation as a linear superposition of the normalized eigenfunctions of the Schrödinger equation for the harmonic oscillator potential. Moreover, we also impose the condition by assuming that some terms in the equation should be so small in order to preserve the use of the perturbation method.
Goffin, Mark A.; Baker, Christopher M.J.; Buchan, Andrew G.; Pain, Christopher C.; Eaton, Matthew D.; Smith, Paul N.
2013-06-01
This article presents a method for goal-based anisotropic adaptive methods for the finite element method applied to the Boltzmann transport equation. The neutron multiplication factor, k{sub eff}, is used as the goal of the adaptive procedure. The anisotropic adaptive algorithm requires error measures for k{sub eff} with directional dependence. General error estimators are derived for any given functional of the flux and applied to k{sub eff} to acquire the driving force for the adaptive procedure. The error estimators require the solution of an appropriately formed dual equation. Forward and dual error indicators are calculated by weighting the Hessian of each solution with the dual and forward residual respectively. The Hessian is used as an approximation of the interpolation error in the solution which gives rise to the directional dependence. The two indicators are combined to form a single error metric that is used to adapt the finite element mesh. The residual is approximated using a novel technique arising from the sub-grid scale finite element discretisation. Two adaptive routes are demonstrated: (i) a single mesh is used to solve all energy groups, and (ii) a different mesh is used to solve each energy group. The second method aims to capture the benefit from representing the flux from each energy group on a specifically optimised mesh. The k{sub eff} goal-based adaptive method was applied to three examples which illustrate the superior accuracy in criticality problems that can be obtained.
Dickerman, J.A.; Silverman, G.S.
1995-12-01
Sustainable development is a phrase that has come into common usage without benefit of clear definition or meaning. Usage very much reflects individual and group perspectives: foresters might consider sustainability in terms of maintaining ecological integrity as part of managing forests for wood harvesting, industry might emphasize pollution control, while government agencies may be looking for new ways to exploit resources on a more continuous basis. Perhaps the greatest commonality among groups considering these issues is that {open_quotes}sustainability{close_quotes} has not been attained but that it needs to occur. The National Association of Environmental Professionals (NAEP) agrees that it is critical to the health of the planet that sustainable development be actively pursued and implemented in international, national, regional, and local policies and practices. To contribute to this effort a {open_quotes}white paper{close_quotes} is being prepared. Its purpose is twofold: (1) to review the existing information from the NAEP Sustainable Development Working Group and the literature and through examination of these policies, to clarify the thinking, what is being done, and what is still needed; and (2) to develop a position and action plan. This action plan should direct NAEP`s actions in making a significant contribution to the national dialog. This paper presents the background and results of the review phase of this white paper development. Representative views on sustainable development policy and practice are presented from three perspectives: governmental agencies, industry, and other specialty groups.
Clustering method and representative feeder selection for the California solar initiative
Broderick, Robert Joseph; Williams, Joseph R.; Munoz-Ramos, Karina
2014-02-01
The screening process for DG interconnection procedures needs to be improved in order to increase the PV deployment level on the distribution grid. A significant improvement in the current screening process could be achieved by finding a method to classify the feeders in a utility service territory and determine the sensitivity of particular groups of distribution feeders to the impacts of high PV deployment levels. This report describes the utility distribution feeder characteristics in California for a large dataset of 8,163 feeders and summarizes the California feeder population including the range of characteristics identified and most important to hosting capacity. The report describes the set of feeders that are identified for modeling and analysis as well as feeders identified for the control group. The report presents a method for separating a utilitys distribution feeders into unique clusters using the k-means clustering algorithm. An approach for determining the feeder variables of interest for use in a clustering algorithm is also described. The report presents an approach for choosing the feeder variables to be utilized in the clustering process and a method is identified for determining the optimal number of representative clusters.
A Control Chart Approach for Representing and Mining Data Streams with Shape Based Similarity
Omitaomu, Olufemi A
2014-01-01
The mining of data streams for online condition monitoring is a challenging task in several domains including (electric) power grid system, intelligent manufacturing, and consumer science. Considering a power grid application in which thousands of sensors, called the phasor measurement units, are deployed on the power grid network to continuously collect streams of digital data for real-time situational awareness and system management. Depending on design, each sensor could stream between ten and sixty data samples per second. The myriad of sensory data captured could convey deeper insights about sequence of events in real-time and before major damages are done. However, the timely processing and analysis of these high-velocity and high-volume data streams is a challenge. Hence, a new data processing and transformation approach, based on the concept of control charts, for representing sequence of data streams from sensors is proposed. In addition, an application of the proposed approach for enhancing data mining tasks such as clustering using real-world power grid data streams is presented. The results indicate that the proposed approach is very efficient for data streams storage and manipulation.
Opal equation-of-state tables for astrophysical applications
Rogers, F.J.; Swenson, F.J.; Iglesias, C.A.
1996-01-01
OPAL opacities have recently helped to resolve a number of long-standing discrepancies between theory and observation. This success has made it important to provide the associated equation-of-state (EOS) data. The OPAL EOS is based on an activity expansion of the grand canonical partition function of the plasma in terms of its fundamental constituents (electrons and nuclei). The formation of composite particles and many-body effects on the internal bound states occur naturally in this approach. Hence, pressure ionization is a consequence of the theory. In contrast, commonly used approaches, all of which are based on minimization of free energy, are forced to assert the effect of the plasma on composite particles and must rely on an ad hoc treatment of pressure ionization. Another advantage of the OPAL approach is that it provides a systematic expansion in the Coulomb coupling parameter that includes subtle quantum effects generally not considered in other EOS calculations. Tables have been generated that provide pressure, internal energy, entropy, and a variety of derivative quantities. These tables cover a fairly broad range of conditions and compositions applicable to general stellar-evolution calculations for stars more massive than {approximately}0.8 {ital M}{sub {circle_dot}}. An interpolation code is provided along with the tables to facilitate their use. {copyright} {ital 1996 The American Astronomical Society.}
Equations of state and phase transitions in stellar matter
Raduta, Ad. R. [IFIN-HH, Bucharest POB-MG 6 (Romania); Gulminelli, F.; Aymard, F. [CNRS, UMR6534, LPC and ENSICAEN, UMR6534, LPC, F-14050 Caen cedex (France); Oertel, M. [LUTH, CNRS, Observatoire de Paris, Universite Paris Diderot, 92195 Meudon (France); Margueron, J. [IPN, IN2P3-CNRS, Universite Paris-Sud, F-91406 Orsay cedex (France)
2014-05-09
Realistic description of core-collapsing supernovae evolution and structure of proto-neutron stars chiefly depends on microphysics input in terms of equations of state, chemical composition and weak interaction rates. At sub-saturation densities the main uncertainty comes from the symmetry energy. Within a nuclear statistical equilibrium (NSE) model with consistent treatment of clusterized and unbound components we investigate the meaning of symmetry energy in the case of dis-homogeneous systems, as the one thought to constitute the neutron star crust, and its sensitivity to the isovector properties of the effective interaction. At supra-saturation densities the situation is much more difficult because of the poor knowledge of nucleon-hyperon and hyperon-hyperon interactions and thermodynamic behavior in terms of phase transitions. Within a simple (np?) model we show that compressed baryonic matter with strangeness manifests a complex phase diagram with first and second order phase transitions. The fact that both are explored under strangeness chemical equilibrium and survive Coulomb suggests that they might have sizable consequences on star evolution. An example in this sense is the drastic reduction of the neutrino-mean free path in the vicinity of the critical point obtained within RPA which would lead to a less rapid star cooling.
Nuclear processing - a simple cost equation or a complex problem?
Banfield, Z.; Banford, A.W.; Hanson, B.C.; Scully, P.J.
2007-07-01
BNFL has extensive experience of nuclear processing plant from concept through to decommissioning, at all stages of the fuel cycle. Nexia Solutions (formerly BNFL's R and D Division) has always supported BNFL in development of concept plant, including the development of costed plant designs for the purpose of economic evaluation and technology selection. Having undertaken such studies over a number of years, this has enabled Nexia Solutions to develop a portfolio of costed plant designs for a broad range of nuclear processes, throughputs and technologies. This work has led to an extensive understanding of the relationship of the cost of nuclear processing plant, and how this can be impacted by scale of process, and the selection of design philosophy. The relationship has been seen to be non linear and so simplistic equations do not apply, the relationship is complex due to the variety of contributory factors. This is particularly evident when considering the scale of a process, for example how step changes in design occurs with increasing scale, how the applicability of technology options can vary with scale etc... This paper will explore the contributory factor of scale to nuclear processing plant costs. (authors)
Test plan for validation of the radiative transfer equation.
Ricks, Allen Joseph; Grasser, Thomas W.; Kearney, Sean Patrick; Jernigan, Dann A.; Blanchat, Thomas K.
2010-09-01
As the capabilities of numerical simulations increase, decision makers are increasingly relying upon simulations rather than experiments to assess risks across a wide variety of accident scenarios including fires. There are still, however, many aspects of fires that are either not well understood or are difficult to treat from first principles due to the computational expense. For a simulation to be truly predictive and to provide decision makers with information which can be reliably used for risk assessment the remaining physical processes must be studied and suitable models developed for the effects of the physics. A set of experiments are outlined in this report which will provide soot volume fraction/temperature data and heat flux (intensity) data for the validation of models for the radiative transfer equation. In addition, a complete set of boundary condition measurements will be taken to allow full fire predictions for validation of the entire fire model. The experiments will be performed with a lightly-sooting liquid hydrocarbon fuel fire in the fully turbulent scale range (2 m diameter).
Wavevortex interactions in the nonlinear Schrdinger equation
Guo, Yuan Bhler, Oliver
2014-02-15
This is a theoretical study of wavevortex interaction effects in the two-dimensional nonlinear Schrdinger equation, which is a useful conceptual model for the limiting dynamics of superfluid quantum condensates at zero temperature. The particular wavevortex interaction effects are associated with the scattering and refraction of small-scale linear waves by the straining flows induced by quantized point vortices and, crucially, with the concomitant nonlinear back-reaction, the remote recoil, that these scattered waves exert on the vortices. Our detailed model is a narrow, slowly varying wavetrain of small-amplitude waves refracted by one or two vortices. Weak interactions are studied using a suitable perturbation method in which the nonlinear recoil force on the vortex then arises at second order in wave amplitude, and is computed in terms of a Magnus-type force expression for both finite and infinite wavetrains. In the case of an infinite wavetrain, an explicit asymptotic formula for the scattering angle is also derived and cross-checked against numerical ray tracing. Finally, under suitable conditions a wavetrain can be so strongly refracted that it collapses all the way onto a zero-size point vortex. This is a strong wavevortex interaction by definition. The conditions for such a collapse are derived and the validity of ray tracing theory during the singular collapse is investigated.
Murphy, M J
2010-03-08
We describe an improved reaction rate equation for simulating ignition and growth of reaction in high explosives. It has been implemented into CALE and ALE3D as an alternate to the baseline the Lee-Tarver reactive flow model. The reactive flow model treats the explosive in two phases (unreacted/reactants and reacted/products) with a reaction rate equation to determine the fraction reacted, F. The improved rate equation has fewer parameters, is continuous with continuous derivative, results in a unique set of reaction rate parameters for each explosive while providing the same functionality as the baseline rate equation. The improved rate equation uses a cosine function in the ignition term and a sine function in the growth and completion terms. The improved rate equation is simpler with fewer parameters.
Equation of state and transport property measurements of warm dense matter.
Knudson, Marcus D.; Desjarlais, Michael Paul
2009-10-01
Location of the liquid-vapor critical point (c.p.) is one of the key features of equation of state models used in simulating high energy density physics and pulsed power experiments. For example, material behavior in the location of the vapor dome is critical in determining how and when coronal plasmas form in expanding wires. Transport properties, such as conductivity and opacity, can vary an order of magnitude depending on whether the state of the material is inside or outside of the vapor dome. Due to the difficulty in experimentally producing states near the vapor dome, for all but a few materials, such as Cesium and Mercury, the uncertainty in the location of the c.p. is of order 100%. These states of interest can be produced on Z through high-velocity shock and release experiments. For example, it is estimated that release adiabats from {approx}1000 GPa in aluminum would skirt the vapor dome allowing estimates of the c.p. to be made. This is within the reach of Z experiments (flyer plate velocity of {approx}30 km/s). Recent high-fidelity EOS models and hydrocode simulations suggest that the dynamic two-phase flow behavior observed in initial scoping experiments can be reproduced, providing a link between theory and experiment. Experimental identification of the c.p. in aluminum would represent the first measurement of its kind in a dynamic experiment. Furthermore, once the c.p. has been experimentally determined it should be possible to probe the electrical conductivity, opacity, reflectivity, etc. of the material near the vapor dome, using a variety of diagnostics. We propose a combined experimental and theoretical investigation with the initial emphasis on aluminum.
Representing northern peatland microtopography and hydrology within the Community Land Model
Shi, X.; Thornton, P. E.; Ricciuto, D. M.; Hanson, P. J.; Mao, J.; Sebestyen, S. D.; Griffiths, N. A.; Bisht, G.
2015-02-20
Predictive understanding of northern peatland hydrology is a necessary precursor to understanding the fate of massive carbon stores in these systems under the influence of present and future climate change. Current models have begun to address microtopographic controls on peatland hydrology, but none have included a prognostic calculation of peatland water table depth for a vegetated wetland, independent of prescribed regional water tables. We introduce here a new configuration of the Community Land Model (CLM) which includes a fully prognostic water table calculation for a vegetated peatland. Our structural and process changes to CLM focus on modifications needed to represent the hydrologic cycle of bogs environment with perched water tables, as well as distinct hydrologic dynamics and vegetation communities of the raised hummock and sunken hollow microtopography characteristic of peatland bogs. The modified model was parameterized and independently evaluated against observations from an ombrotrophic raised-dome bog in northern Minnesota (S1-Bog), the site for the Spruce and Peatland Responses Under Climatic and Environmental Change experiment (SPRUCE). Simulated water table levels compared well with site-level observations. The new model predicts significant hydrologic changes in response to planned warming at the SPRUCE site. At present, standing water is commonly observed in bog hollows after large rainfall events during the growing season, but simulations suggest a sharp decrease in water table levels due to increased evapotranspiration under the most extreme warming level, nearly eliminating the occurrence of standing water in the growing season. Simulated soil energy balance was strongly influenced by reduced winter snowpack under warming simulations, with the warming influence on soil temperature partly offset by the loss of insulating snowpack in early and late winter. The new model provides improved predictive capacity for seasonal hydrological dynamics in northern peatlands, and provides a useful foundation for investigation of northern peatland carbon exchange.
An asymptotic expansion of the solution of amatrix difference equation of general form
Sgibnev, M S
2014-12-31
An asymptotic expansion of the solution of an inhomogeneous matrix difference equation of general form is obtained. The case when there is no bound on the differences of the arguments is considered. The effect of the roots of the characteristic equation is taken into account. An integral estimate with asubmultiplicative weight is established for the remainder in terms of the submultiplicative moment of the free term of the equation. Bibliography: 14 titles.
Solitary waves in nonlinear Dirac equation. From field theory to Dirac materials
Saxena, Avadh
2015-11-02
This report describes the implementation of nonlinear Dirac equations in the calculation of solitary waves. Conclusions and comments on quantum elasticity are also included.
A Novel Hyperbolization Procedure for The Two-Phase Six-Equation Flow Model
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(Technical Report) | SciTech Connect Technical Report: A Novel Hyperbolization Procedure for The Two-Phase Six-Equation Flow Model Citation Details In-Document Search Title: A Novel Hyperbolization Procedure for The Two-Phase Six-Equation Flow Model We introduce a novel approach for the hyperbolization of the well-known two-phase six equation flow model. The six-equation model has been frequently used in many two-phase flow applications such as bubbly fluid flows in nuclear reactors. One
The thermal equation of state of (Mg, Fe)SiO[subscript 3] bridgmanite...
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thermal equation of state of (Mg, Fe)SiOsubscript 3 bridgmanite (perovskite) and implications for lower mantle structures Citation Details In-Document Search Title: The thermal ...
Equation of state and phase diagram of FeO (Journal Article)...
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high temperature behavior of FeO, including its phase diagram and equation of state, is essential knowledge for understanding the properties and evolution of Earth's deep interior. ...
Ayyoubzadeh, Seyed Mohsen; Vosoughi, Naser
2011-09-14
Obtaining the set of algebraic equations that directly correspond to a physical phenomenon has been viable in the recent direct discrete method (DDM). Although this method may find its roots in physical and geometrical considerations, there are still some degrees of freedom that one may suspect optimize-able. Here we have used the information embedded in the corresponding adjoint equation to form a local functional, which in turn by its minimization, yield suitable dual mesh positioning.
None
2010-12-29
The representative concentration pathway to be delivered is a scenario of atmospheric concentrations of greenhouse gases and other radiatively important atmospheric species, along with land-use changes, derived from the Global Change Assessment Model (GCAM). The particular representative concentration pathway (RCP) that the Joint Global Change Research Institute (JGCRI) has been responsible for is a not-to-exceed pathway that stabilizes at a radiative forcing of 4.5Wm-2 in the year 2100.
A Hydro-Economic Approach to Representing Water Resources Impacts in Integrated Assessment Models
Kirshen, Paul H.; Strzepek, Kenneth, M.
2004-01-14
Grant Number DE-FG02-98ER62665 Office of Energy Research of the U.S. Department of Energy Abstract Many Integrated Assessment Models (IAM) divide the world into a small number of highly aggregated regions. Non-OECD countries are aggregated geographically into continental and multiple-continental regions or economically by development level. Current research suggests that these large scale aggregations cannot accurately represent potential water resources-related climate change impacts. In addition, IAMs do not explicitly model the flow regulation impacts of reservoir and ground water systems, the economics of water supply, or the demand for water in economic activities. Using the International Model for Policy Analysis of Agricultural Commodities and Trade (IMPACT) model of the International Food Policy Research Institute (IFPRI) as a case study, this research implemented a set of methodologies to provide accurate representation of water resource climate change impacts in Integrated Assessment Models. There were also detailed examinations of key issues related to aggregated modeling including: modeling water consumption versus water withdrawals; ground and surface water interactions; development of reservoir cost curves; modeling of surface areas of aggregated reservoirs for estimating evaporation losses; and evaluating the importance of spatial scale in river basin modeling. The major findings include: - Continental or national or even large scale river basin aggregation of water supplies and demands do not accurately capture the impacts of climate change in the water and agricultural sector in IAMs. - Fortunately, there now exist gridden approaches (0.5 X 0.5 degrees) to model streamflows in a global analysis. The gridded approach to hydrologic modeling allows flexibility in aligning basin boundaries with national boundaries. This combined with GIS tools, high speed computers, and the growing availability of socio-economic gridded data bases allows assignment of demands to river basins to create hydro-economic zones that respect as much as possible both political and hydrologic integrity in different models. - To minimize pre-processing of data and add increased flexibility to modeling water resources and uses, it is recommended that water withdrawal demands be modeled, not consumptive requirements even though this makes the IAM more complex. - IAMs must consider changes in water availability for irrigation under climate change; ignoring them is more inaccurate than ignoring yield changes in crops under climate change. - Determining water availability and cost in river basins must include modeling streamflows, reservoirs and their operations, and ground water and its interaction with surface water. - Scale issues are important. The results from condensing demands and supplies in a large complex river basin to one node can be misleading for all uses under low flow conditions and instream flow uses under all conditions. Monthly is generally the most accurate scale for modeling river flows and demands. Challenges remain in integrating hydrologic units with political boundaries but the gridded approach to hydrologic modeling allows flexibility in aligning basin boundaries with political boundaries. - Using minimal reservoir cost data, it is possible to use basin topography to estimate reservoir storage costs. - Reservoir evaporation must be considered when assessing the usable water in a watershed. Several methods are available to estimate the relationship between aggregated storage surface area and storage volume. - For existing or future IAMs that can not use the appropriate aggregation for water, a water preprocessor may be required due the finer scale of hydrologic impacts.
A parametric approach to supersymmetric quantum mechanics in the solution of Schrdinger equation
Tezcan, Cevdet; Sever, Ramazan
2014-03-15
We study exact solutions of the Schrdinger equation for some potentials. We introduce a parametric approach to supersymmetric quantum mechanics to calculate energy eigenvalues and corresponding wave functions exactly. As an application we solve Schrdinger equation for the generalized Morse potential, modified Hulthen potential, deformed Rosen-Morse potential and Poschl-Teller potential. The method is simple and effective to get the results.
Explicit solutions of the radiative transport equation in the P{sub 3} approximation
Liemert, André Kienle, Alwin
2014-11-01
Purpose: Explicit solutions of the monoenergetic radiative transport equation in the P{sub 3} approximation have been derived which can be evaluated with nearly the same computational effort as needed for solving the standard diffusion equation (DE). In detail, the authors considered the important case of a semi-infinite medium which is illuminated by a collimated beam of light. Methods: A combination of the classic spherical harmonics method and the recently developed method of rotated reference frames is used for solving the P{sub 3} equations in closed form. Results: The derived solutions are illustrated and compared to exact solutions of the radiative transport equation obtained via the Monte Carlo (MC) method as well as with other approximated analytical solutions. It is shown that for the considered cases which are relevant for biomedical optics applications, the P{sub 3} approximation is close to the exact solution of the radiative transport equation. Conclusions: The authors derived exact analytical solutions of the P{sub 3} equations under consideration of boundary conditions for defining a semi-infinite medium. The good agreement to Monte Carlo simulations in the investigated domains, for example, in the steady-state and time domains, as well as the short evaluation time needed suggests that the derived equations can replace the often applied solutions of the diffusion equation for the homogeneous semi-infinite medium.
Symmetry operators for Dirac's equation on two-dimensional spin manifolds
Fatibene, Lorenzo; McLenaghan, Raymond G.; Smith, Shane N.; Rastelli, Giovanni
2009-05-15
It is shown that the second order symmetry operators for the Dirac equation on a general two-dimensional spin manifold may be expressed in terms of Killing vectors and valence 2 Killing tensors. The role of these operators in the theory of separation of variables for the Dirac equation is studied.
Nakatsuji, Hiroshi Nakashima, Hiroyuki
2015-02-28
The free-complement (FC) method is a general method for solving the Schrdinger equation (SE): The produced wave function has the potentially exact structure as the solution of the Schrdinger equation. The variables included are determined either by using the variational principle (FC-VP) or by imposing the local Schrdinger equations (FC-LSE) at the chosen set of the sampling points. The latter method, referred to as the local Schrdinger equation (LSE) method, is integral-free and therefore applicable to any atom and molecule. The purpose of this paper is to formulate the basic theories of the LSE method and explain their basic features. First, we formulate three variants of the LSE method, the AB, HS, and H{sup T}Q methods, and explain their properties. Then, the natures of the LSE methods are clarified in some detail using the simple examples of the hydrogen atom and the Hookes atom. Finally, the ideas obtained in this study are applied to solving the SE of the helium atom highly accurately with the FC-LSE method. The results are very encouraging: we could get the worlds most accurate energy of the helium atom within the sampling-type methodologies, which is comparable to those obtained with the FC-VP method. Thus, the FC-LSE method is an easy and yet a powerful integral-free method for solving the Schrdinger equation of general atoms and molecules.
Explicit Expressions for 3D Boundary Integrals in Potential Theory
Nintcheu Fata, Sylvain
2009-01-01
On employing isoparametric, piecewise linear shape functions over a flat triangular domain, exact expressions are derived for all surface potentials involved in the numerical solution of three-dimensional singular and hyper-singular boundary integral equations of potential theory. These formulae, which are valid for an arbitrary source point in space, are represented as analytic expressions over the edges of the integration triangle. They can be used to solve integral equations defined on polygonal boundaries via the collocation method or may be utilized as analytic expressions for the inner integrals in the Galerkin technique. Also, the constant element approximation can be directly obtained with no extra effort. Sample problems solved by the collocation boundary element method for the Laplace equation are included to validate the proposed formulae.
Equation of State from Lattice QCD Calculations (Conference) | SciTech
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Connect Conference: Equation of State from Lattice QCD Calculations Citation Details In-Document Search Title: Equation of State from Lattice QCD Calculations We provide a status report on the calculation of the Equation of State (EoS) of QCD at finite temperature using lattice QCD. Most of the discussion will focus on comparison of recent results obtained by the HotQCD and Wuppertal-Budapest collaborations. We will show that very significant progress has been made towards obtaining high
A stochastic multi-symplectic scheme for stochastic Maxwell equations with additive noise
Hong, Jialin; Zhang, Liying
2014-07-01
In this paper we investigate a stochastic multi-symplectic method for stochastic Maxwell equations with additive noise. Based on the stochastic version of variational principle, we find a way to obtain the stochastic multi-symplectic structure of three-dimensional (3-D) stochastic Maxwell equations with additive noise. We propose a stochastic multi-symplectic scheme and show that it preserves the stochastic multi-symplectic conservation law and the local and global stochastic energy dissipative properties, which the equations themselves possess. Numerical experiments are performed to verify the numerical behaviors of the stochastic multi-symplectic scheme.
Error propagation equations for estimating the uncertainty in high-speed wind tunnel test results
Clark, E.L.
1994-07-01
Error propagation equations, based on the Taylor series model, are derived for the nondimensional ratios and coefficients most often encountered in high-speed wind tunnel testing. These include pressure ratio and coefficient, static force and moment coefficients, dynamic stability coefficients, and calibration Mach number. The error equations contain partial derivatives, denoted as sensitivity coefficients, which define the influence of free-steam Mach number, M{infinity}, on various aerodynamic ratios. To facilitate use of the error equations, sensitivity coefficients are derived and evaluated for five fundamental aerodynamic ratios which relate free-steam test conditions to a reference condition.
Boyarinov, V. F.; Kondrushin, A. E.; Fomichenko, P. A.
2012-07-01
Finite-difference time-dependent equations of Surface Harmonics method have been obtained for plane geometry. Verification of these equations has been carried out by calculations of tasks from 'Benchmark Problem Book ANL-7416'. The capacity and efficiency of the Surface Harmonics method have been demonstrated by solution of the time-dependent neutron transport equation in diffusion approximation. The results of studies showed that implementation of Surface Harmonics method for full-scale calculations will lead to a significant progress in the efficient solution of the time-dependent neutron transport problems in nuclear reactors. (authors)
Imaginary Time Step Method to Solve the Dirac Equation with Nonlocal Potential
Zhang Ying [State Key Lab Nucl. Phys. and Tech., School of Physics, Peking University, Beijing 100871 (China); Liang Haozhao [State Key Lab Nucl. Phys. and Tech., School of Physics, Peking University, Beijing 100871 (China); Institut de Physique Nucleaire, IN2P3-CNRS and Universite Paris-Sud, F-91406 Orsay France (France); Meng Jie [State Key Lab Nucl. Phys. and Tech., School of Physics, Peking University, Beijing 100871 (China); Department of Physics, University of Stellenbosch, Stellenbosch (South Africa)
2009-08-26
The imaginary time step (ITS) method is applied to solve the Dirac equation with nonlocal potentials in coordinate space. Taking the nucleus {sup 12}C as an example, even with nonlocal potentials, the direct ITS evolution for the Dirac equation still meets the disaster of the Dirac sea. However, following the recipe in our former investigation, the disaster can be avoided by the ITS evolution for the corresponding Schroedinger-like equation without localization, which gives the convergent results exactly the same with those obtained iteratively by the shooting method with localized effective potentials.
Daeva, S.G.; Setukha, A.V.
2015-03-10
A numerical method for solving a problem of diffraction of acoustic waves by system of solid and thin objects based on the reduction the problem to a boundary integral equation in which the integral is understood in the sense of finite Hadamard value is proposed. To solve this equation we applied piecewise constant approximations and collocation methods numerical scheme. The difference between the constructed scheme and earlier known is in obtaining approximate analytical expressions to appearing system of linear equations coefficients by separating the main part of the kernel integral operator. The proposed numerical scheme is tested on the solution of the model problem of diffraction of an acoustic wave by inelastic sphere.
Validity of equation-of-motion approach to kondo problem in the large N
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limit (Journal Article) | SciTech Connect SciTech Connect Search Results Journal Article: Validity of equation-of-motion approach to kondo problem in the large N limit Citation Details In-Document Search Title: Validity of equation-of-motion approach to kondo problem in the large N limit The Anderson impurity model for Kondo problem is investigated for arbitrary orbit-spin degeneracy N of the magnetic impurity by the equation of motion method (EOM). By employing a new decoupling scheme, a
Schneider, K.J.
1982-09-01
The Fuel Cycle Risk Assessment Program was initiated to provide risk assessment methods for assistance in the regulatory process for nuclear fuel cycle facilities other than reactors. This report, the first from the program, defines and describes fuel cycle elements that are being considered in the program. One type of facility (and in some cases two) is described that is representative of each element of the fuel cycle. The descriptions are based on real industrial-scale facilities that are current state-of-the-art, or on conceptual facilities where none now exist. Each representative fuel cycle facility is assumed to be located on the appropriate one of four hypothetical but representative sites described. The fuel cycles considered are for Light Water Reactors with once-through flow of spent fuel, and with plutonium and uranium recycle. Representative facilities for the following fuel cycle elements are described for uranium (or uranium plus plutonium where appropriate): mining, milling, conversion, enrichment, fuel fabrication, mixed-oxide fuel refabrication, fuel reprocessing, spent fuel storage, high-level waste storage, transuranic waste storage, spent fuel and high-level and transuranic waste disposal, low-level and intermediate-level waste disposal, and transportation. For each representative facility the description includes: mainline process, effluent processing and waste management, facility and hardware description, safety-related information and potential alternative concepts for that fuel cycle element. The emphasis of the descriptive material is on safety-related information. This includes: operating and maintenance requirements, input/output of major materials, identification and inventories of hazardous materials (particularly radioactive materials), unit operations involved, potential accident driving forces, containment and shielding, and degree of hands-on operation.
Quasiparticle description of (2+1)- flavor lattice QCD equation of state
Chandra, Vinod; Ravishankar, V.
2011-10-01
A quasiparticle model has been employed to describe the (2+1)-flavor lattice QCD equation of state with physical quark masses. The interaction part of the equation of state has been mapped to the effective fugacities of otherwise noninteracting quasigluons and quasiquarks. The mapping is found to be exact for the equation of state. The model leads to nontrivial dispersion relations for quasipartons. The dispersion relations, effective quasiparticle number densities, and trace anomaly have been investigated employing the model. A virial expansion for the equation of state has further been obtained to investigate the role of interactions in quark-gluon plasma. Finally, Debye screening in quark-gluon plasma has been studied employing the model.
Equation of state and phase diagram of Fe-16Si alloy as a candidate...
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SciTech Connect Search Results Journal Article: Equation of state and phase diagram of Fe-16Si alloy as a candidate component of Earths core Citation Details In-Document Search ...
Brett, Tobias Galla, Tobias
2014-03-28
We present a heuristic derivation of Gaussian approximations for stochastic chemical reaction systems with distributed delay. In particular, we derive the corresponding chemical Langevin equation. Due to the non-Markovian character of the underlying dynamics, these equations are integro-differential equations, and the noise in the Gaussian approximation is coloured. Following on from the chemical Langevin equation, a further reduction leads to the linear-noise approximation. We apply the formalism to a delay variant of the celebrated Brusselator model, and show how it can be used to characterise noise-driven quasi-cycles, as well as noise-triggered spiking. We find surprisingly intricate dependence of the typical frequency of quasi-cycles on the delay period.
Electrolux Gibson Air Conditioner and Equator Clothes Washer Fail DOE Energy Star Testing
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DOE testing in support of the ENERGY STAR program has revealed that an Electrolux Gibson air conditioner (model GAH105Q2T1) and an Equator clothes washer (model EZ 3720 CEE), both of which claimed...
Equation of state of pyrite to 80 GPa and 2400 K (Journal Article...
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Citation Details In-Document Search Title: Equation of state of pyrite to 80 GPa and 2400 K Authors: Thompson, Elizabeth C. ; Chidester, Bethany A. ; Fischer, Rebecca A. ; Myers, ...
Symmetries of the triple degenerate DNLS equations for weakly nonlinear dispersive MHD waves
Webb, G. M.; Brio, M.; Zank, G. P.
1996-07-20
A formulation of Hamiltonian and Lagrangian variational principles, Lie point symmetries and conservation laws for the triple degenerate DNLS equations describing the propagation of weakly nonlinear dispersive MHD waves along the ambient magnetic field, in {beta}{approx}1 plasmas is given. The equations describe the interaction of the Alfven and magnetoacoustic modes near the triple umbilic point, where the fast magnetosonic, slow magnetosonic and Alfven speeds coincide and a{sub g}{sup 2}=V{sub A}{sup 2} where a{sub g} is the gas sound speed and V{sub A} is the Alfven speed. A discussion is given of the travelling wave similarity solutions of the equations, which include solitary wave and periodic traveling waves. Strongly compressible solutions indicate the necessity for the insertion of shocks in the flow, whereas weakly compressible, near Alfvenic solutions resemble similar, shock free travelling wave solutions of the DNLS equation.
A Novel Hyperbolization Procedure for The Two-Phase Six-Equation...
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A Novel Hyperbolization Procedure for The Two-Phase Six-Equation Flow Model Citation Details In-Document Search Title: A Novel Hyperbolization Procedure for The Two-Phase...
New Improved Equations For Na-K, Na-Li And Sio2 Geothermometers...
Improved Equations For Na-K, Na-Li And Sio2 Geothermometers By Outlier Detection And Rejection Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article:...
Effects of the Fe[superscript 3+] spin transition on the equation...
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Title: Effects of the Fesuperscript 3+ spin transition on the equation of state of bridgmanite Authors: Mao, Zhu ; Lin, Jung-Fu ; Yang, Jing ; Inoue, Toru ; Prakapenka, Vitali B. ...
A Novel Hyperbolization Procedure for The Two-Phase Six-Equation...
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Technical Report: A Novel Hyperbolization Procedure for The Two-Phase Six-Equation Flow Model Citation Details In-Document Search Title: A Novel Hyperbolization Procedure for The ...
Fa, Kwok Sau
2015-02-15
An integro-differential diffusion equation with linear force, based on the continuous time random walk model, is considered. The equation generalizes the ordinary and fractional diffusion equations, which includes short, intermediate and long-time memory effects described by the waiting time probability density function. Analytical expression for the correlation function is obtained and analyzed, which can be used to describe, for instance, internal motions of proteins. The result shows that the generalized diffusion equation has a broad application and it may be used to describe different kinds of systems. - Highlights: • Calculation of the correlation function. • The correlation function is connected to the survival probability. • The model can be applied to the internal dynamics of proteins.
H–J–B Equations of Optimal Consumption-Investment and Verification Theorems
Nagai, Hideo
2015-04-15
We consider a consumption-investment problem on infinite time horizon maximizing discounted expected HARA utility for a general incomplete market model. Based on dynamic programming approach we derive the relevant H–J–B equation and study the existence and uniqueness of the solution to the nonlinear partial differential equation. By using the smooth solution we construct the optimal consumption rate and portfolio strategy and then prove the verification theorems under certain general settings.
Equations Governing Space-Time Variability of Liquid Water Path in Stratus Clouds
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Equations Governing Space-Time Variability of Liquid Water Path in Stratus Clouds K. Ivanova Pennsylvania State University University Park, Pennsylvania T. P. Ackerman Pacific Northwest National Laboratory Richland, Washington M. Ausloos University of Liège B-4000 Liège, Belgium Abstract We present a method on how to derive an underlying mathematical (statistical or model free) equation for a liquid water path (LWP) signal directly from empirical data. The evolution of the probability density
Analytical continuation from bound to resonant states in the Dirac equation
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with quadrupole-deformed potentials (Journal Article) | SciTech Connect Analytical continuation from bound to resonant states in the Dirac equation with quadrupole-deformed potentials Citation Details In-Document Search This content will become publicly available on August 27, 2016 Title: Analytical continuation from bound to resonant states in the Dirac equation with quadrupole-deformed potentials Authors: Xu, Xu-Dong ; Zhang, Shi-Sheng ; Signoracci, A. J. ; Smith, M. S. ; Li, Z. P.
ANALYSIS OF TWO-PHASE FLOW MODELS WITH TWO MOMENTUM EQUATIONS.
KROSHILIN,A.E.KROSHILIN,V.E.KOHUT,P.
2004-03-15
An analysis of the standard system of differential equations describing multi-speed flows of multi-phase media is performed. It is proved that the Cauchy problem, as posed in most best-estimate thermal-hydraulic codes, results in unstable solutions and potentially unreliable description of many physical phenomena. A system of equations, free from instability effects, is developed allowing more rigorous numerical modeling.
Investigating the Nuclear Equation of State through N/Z Equilibration
Yennello, S.; Keksis, A.; Bell, E.
2007-10-26
The equilibration of the N/Z degree of freedom during heavy-ion collisions can be a discriminating observables for helping to understand the nuclear equation of state. Equilibration can be investigated by examining the ratios of isotopes produced in these reactions. The isotope ratio method and the tracer method yield consistent results. The quasiprojectiles produced in deep inelastic collisions are predicted to be sensitive to the density dependence of the equation of state.
Equations of state in the Fe-FeSi system at high pressures and temperatures
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(Journal Article) | SciTech Connect SciTech Connect Search Results Journal Article: Equations of state in the Fe-FeSi system at high pressures and temperatures Citation Details In-Document Search Title: Equations of state in the Fe-FeSi system at high pressures and temperatures Authors: Fischer, Rebecca A. ; Campbell, Andrew J. ; Caracas, Razvan ; Reaman, Daniel M. ; Heinz, Dion L. ; Dera, Przemyslaw ; Prakapenka, Vitali B. [1] ; UC) [2] ; Claude-Bernard) [2] + Show Author Affiliations
Hydrodynamic equations for electrons in graphene obtained from the maximum entropy principle
Barletti, Luigi
2014-08-15
The maximum entropy principle is applied to the formal derivation of isothermal, Euler-like equations for semiclassical fermions (electrons and holes) in graphene. After proving general mathematical properties of the equations so obtained, their asymptotic form corresponding to significant physical regimes is investigated. In particular, the diffusive regime, the Maxwell-Boltzmann regime (high temperature), the collimation regime and the degenerate gas limit (vanishing temperature) are considered.
Exact solution to the Schrödinger’s equation with pseudo-Gaussian potential
Iacob, Felix; Lute, Marina
2015-12-15
We consider the radial Schrödinger equation with the pseudo-Gaussian potential. By making an ansatz to the solution of the eigenvalue equation for the associate Hamiltonian, we arrive at the general exact eigenfunction. The values of energy levels for the bound states are calculated along with their corresponding normalized wave-functions. The case of positive energy levels, known as meta-stable states, is also discussed and the magnitude of transmission coefficient through the potential barrier is evaluated.
A New 2D-Transport, 1D-Diffusion Approximation of the Boltzmann Transport equation
Larsen, Edward
2013-06-17
The work performed in this project consisted of the derivation, implementation, and testing of a new, computationally advantageous approximation to the 3D Boltz- mann transport equation. The solution of the Boltzmann equation is the neutron flux in nuclear reactor cores and shields, but solving this equation is difficult and costly. The new 2D/1D approximation takes advantage of a special geometric feature of typical 3D reactors to approximate the neutron transport physics in a specific (ax- ial) direction, but not in the other two (radial) directions. The resulting equation is much less expensive to solve computationally, and its solutions are expected to be sufficiently accurate for many practical problems. In this project we formulated the new equation, discretized it using standard methods, developed a stable itera- tion scheme for solving the equation, implemented the new numerical scheme in the MPACT code, and tested the method on several realistic problems. All the hoped- for features of this new approximation were seen. For large, difficult problems, the resulting 2D/1D solution is highly accurate, and is calculated about 100 times faster than a 3D discrete ordinates simulation.
Cari, C. Suparmi, A.
2014-09-30
Dirac equation of 3D harmonics oscillator plus trigonometric Scarf non-central potential for spin symmetric case is solved using supersymmetric quantum mechanics approach. The Dirac equation for exact spin symmetry reduces to Schrodinger like equation. The relativistic energy and wave function for spin symmetric case are simply obtained using SUSY quantum mechanics method and idea of shape invariance.
Construction Control Representative
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(See Frequently Asked Questions for more information). Where would I be working? Western Area Power Administration Rocky Mountain Region Engineering and Construction Field Engineering, (J5600) 5555...
Santos, N. D.; Blaise, P.; Santamarina, A.
2013-07-01
The development of new types of reactor and the increase in the safety specifications and requirements induce an enhancement in both nuclear data knowledge and a better understanding of the neutronic properties of the new systems. This enhancement is made possible using ad hoc critical mock-up experiments. The main difficulty is to design these experiments in order to obtain the most valuable information. Its quantification is usually made by using representativity and transposition concepts. These theories enable to extract some information about a quantity of interest (an integral parameter) on a configuration, but generally a posteriori. This paper presents a more global approach of this theory, with the idea of optimizing the representativity of a new experiment, and its transposition a priori, based on a multiparametric approach. Using a quadratic sum, we show the possibility to define a global representativity which permits to take into account several quantities of interest at the same time. The maximization of this factor gives information about all quantities of interest. An optimization method of this value in relation to technological parameters (over-clad diameter, atom concentration) is illustrated on a high-conversion light water reactor MOX lattice case. This example tackles the problematic of plutonium experiment for the plutonium aging and a solution through the optimization of both the over-clad and the plutonium content. (authors)
An asymptotic preserving unified gas kinetic scheme for gray radiative transfer equations
Sun, Wenjun; Jiang, Song; Xu, Kun
2015-03-15
The solutions of radiative transport equations can cover both optical thin and optical thick regimes due to the large variation of photon's mean-free path and its interaction with the material. In the small mean free path limit, the nonlinear time-dependent radiative transfer equations can converge to an equilibrium diffusion equation due to the intensive interaction between radiation and material. In the optical thin limit, the photon free transport mechanism will emerge. In this paper, we are going to develop an accurate and robust asymptotic preserving unified gas kinetic scheme (AP-UGKS) for the gray radiative transfer equations, where the radiation transport equation is coupled with the material thermal energy equation. The current work is based on the UGKS framework for the rarefied gas dynamics [14], and is an extension of a recent work [12] from a one-dimensional linear radiation transport equation to a nonlinear two-dimensional gray radiative system. The newly developed scheme has the asymptotic preserving (AP) property in the optically thick regime in the capturing of diffusive solution without using a cell size being smaller than the photon's mean free path and time step being less than the photon collision time. Besides the diffusion limit, the scheme can capture the exact solution in the optical thin regime as well. The current scheme is a finite volume method. Due to the direct modeling for the time evolution solution of the interface radiative intensity, a smooth transition of the transport physics from optical thin to optical thick can be accurately recovered. Many numerical examples are included to validate the current approach.
Stability and error analysis of nodal expansion method for convection-diffusion equation
Deng, Z.; Rizwan-Uddin; Li, F.; Sun, Y.
2012-07-01
The development, and stability and error analyses of nodal expansion method (NEM) for one dimensional steady-state convection diffusion equation is presented. Following the traditional procedure to develop NEM, the discrete formulation of the convection-diffusion equation, which is similar to the standard finite difference scheme, is derived. The method of discrete perturbation analysis is applied to this discrete form to study the stability of the NEM. The scheme based on the NEM is found to be stable for local Peclet number less than 4.644. A maximum principle is proved for the NEM scheme, followed by an error analysis carried out by applying the Maximum principle together with a carefully constructed comparison function. The scheme for the convection diffusion equation is of second-order. Numerical experiments are carried and the results agree with the conclusions of the stability and error analyses. (authors)
Equation of state of hot polarized nuclear matter and heavy-ion fusion reactions
Ghodsi, O. N.; Gharaei, R.
2011-08-15
We employ the equation of state of hot polarized nuclear matter to simulate the repulsive force caused by the incompressibility effects of nuclear matter in the fusion reactions of heavy colliding ions. The results of our studies reveal that temperature effects of compound nuclei have significant importance in simulating the repulsive force on the fusion reactions for which the temperature of the compound nucleus increases up to about 2 MeV. Since the equation of state of hot nuclear matter depends upon the density and temperature of the nuclear matter, it has been suggested that, by using this equation of state, one can simulate simultaneously both the effects of the precompound nucleons' emission and the incompressibility of nuclear matter to calculate the nuclear potential in fusion reactions within a static formalism such as the double-folding (DF) model.
Multi-time Schrödinger equations cannot contain interaction potentials
Petrat, Sören; Tumulka, Roderich
2014-03-15
Multi-time wave functions are wave functions that have a time variable for every particle, such as ϕ(t{sub 1},x{sub 1},...,t{sub N},x{sub N}). They arise as a relativistic analog of the wave functions of quantum mechanics but can be applied also in quantum field theory. The evolution of a wave function with N time variables is governed by N Schrödinger equations, one for each time variable. These Schrödinger equations can be inconsistent with each other, i.e., they can fail to possess a joint solution for every initial condition; in fact, the N Hamiltonians need to satisfy a certain commutator condition in order to be consistent. While this condition is automatically satisfied for non-interacting particles, it is a challenge to set up consistent multi-time equations with interaction. We prove for a wide class of multi-time Schrödinger equations that the presence of interaction potentials (given by multiplication operators) leads to inconsistency. We conclude that interaction has to be implemented instead by creation and annihilation of particles, which, in fact, can be done consistently [S. Petrat and R. Tumulka, “Multi-time wave functions for quantum field theory,” Ann. Physics (to be published)]. We also prove the following result: When a cut-off length δ > 0 is introduced (in the sense that the multi-time wave function is defined only on a certain set of spacelike configurations, thereby breaking Lorentz invariance), then the multi-time Schrödinger equations with interaction potentials of range δ are consistent; however, in the desired limit δ → 0 of removing the cut-off, the resulting multi-time equations are interaction-free, which supports the conclusion expressed in the title.
First-principles high-pressure unreacted equation of state and heat of
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formation of crystal 2,6-diamino-3, 5-dinitropyrazine-1-oxide (LLM-105) (Journal Article) | SciTech Connect Journal Article: First-principles high-pressure unreacted equation of state and heat of formation of crystal 2,6-diamino-3, 5-dinitropyrazine-1-oxide (LLM-105) Citation Details In-Document Search Title: First-principles high-pressure unreacted equation of state and heat of formation of crystal 2,6-diamino-3, 5-dinitropyrazine-1-oxide (LLM-105) Authors: Manaa, M R ; Kuo, I W ; Fried, L
Verification of the history-score moment equations for weight-window variance reduction
Solomon, Clell J; Sood, Avneet; Booth, Thomas E; Shultis, J. Kenneth
2010-12-06
The history-score moment equations that describe the moments of a Monte Carlo score distribution have been extended to weight-window variance reduction, The resulting equations have been solved deterministically to calculate the population variance of the Monte Carlo score distribution for a single tally, Results for one- and two-dimensional one-group problems are presented that predict the population variances to less than 1% deviation from the Monte Carlo for one-dimensional problems and between 1- 2% for two-dimensional problems,
Moawad, S. M.
2015-02-15
In this paper, we present a solution method for constructing exact analytic solutions to magnetohydrodynamics (MHD) equations. The method is constructed via all the trigonometric and hyperbolic functions. The method is applied to MHD equilibria with mass flow. Applications to a solar system concerned with the properties of coronal mass ejections that affect the heliosphere are presented. Some examples of the constructed solutions which describe magnetic structures of solar eruptions are investigated. Moreover, the constructed method can be applied to a variety classes of elliptic partial differential equations which arise in plasma physics.
Thermal equation of state and stability of (Mg[subscript 0.06]Fe[subscript
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0.94])O (Journal Article) | SciTech Connect SciTech Connect Search Results Journal Article: Thermal equation of state and stability of (Mg[subscript 0.06]Fe[subscript 0.94])O Citation Details In-Document Search Title: Thermal equation of state and stability of (Mg[subscript 0.06]Fe[subscript 0.94])O Authors: Wicks, June K. ; Jackson, Jennifer M. ; Sturhahn, Wolfgang ; Zhuravlev, Kirill K. ; Tkachev, Sergey N. ; Prakapenka, Vitali B. [1] ; UC) [2] ; CIT) [2] + Show Author Affiliations
Validity of equation-of-motion approach to kondo problem in the large N
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limit (Journal Article) | SciTech Connect Validity of equation-of-motion approach to kondo problem in the large N limit Citation Details In-Document Search Title: Validity of equation-of-motion approach to kondo problem in the large N limit × You are accessing a document from the Department of Energy's (DOE) SciTech Connect. This site is a product of DOE's Office of Scientific and Technical Information (OSTI) and is provided as a public service. Visit OSTI to utilize additional information
A New Lifshitz Transition and the Equation of State of Osmium (Journal
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Article) | SciTech Connect A New Lifshitz Transition and the Equation of State of Osmium Citation Details In-Document Search Title: A New Lifshitz Transition and the Equation of State of Osmium × You are accessing a document from the Department of Energy's (DOE) SciTech Connect. This site is a product of DOE's Office of Scientific and Technical Information (OSTI) and is provided as a public service. Visit OSTI to utilize additional information resources in energy science and technology. A
Phase Diagram and Equation of State of Magnesium to High Pressures and High
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Temperatures (Journal Article) | SciTech Connect Phase Diagram and Equation of State of Magnesium to High Pressures and High Temperatures Citation Details In-Document Search Title: Phase Diagram and Equation of State of Magnesium to High Pressures and High Temperatures Authors: Stinton, G W ; MacLeod, S G ; Cynn, H ; Errandonea, D ; Evans, W J ; Proctor, J E ; Meng, Y ; McMahon, M I Publication Date: 2014-01-21 OSTI Identifier: 1188628 Report Number(s): LLNL-JRNL-648674 DOE Contract Number:
Effects of the Fe[superscript 3+] spin transition on the equation of state
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of bridgmanite (Journal Article) | SciTech Connect SciTech Connect Search Results Journal Article: Effects of the Fe[superscript 3+] spin transition on the equation of state of bridgmanite Citation Details In-Document Search Title: Effects of the Fe[superscript 3+] spin transition on the equation of state of bridgmanite Authors: Mao, Zhu ; Lin, Jung-Fu ; Yang, Jing ; Inoue, Toru ; Prakapenka, Vitali B. [1] ; UC) [2] ; CHPSTAR- China) [2] ; Ehime U) [2] + Show Author Affiliations (Texas) (
Equation of state and phase diagram of Fe-16Si alloy as a candidate
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component of Earth's core (Journal Article) | SciTech Connect SciTech Connect Search Results Journal Article: Equation of state and phase diagram of Fe-16Si alloy as a candidate component of Earth's core Citation Details In-Document Search Title: Equation of state and phase diagram of Fe-16Si alloy as a candidate component of Earth's core The outer core of the Earth contains several weight percent of one or more unknown light elements, which may include silicon. Therefore it is critical to
Constraining the equation of state of superhadronic matter from heavy-ion collisions
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Pratt, Scott; Sorensen, Paul; Sangaline, Evan; Wang, Hui
2015-05-19
The equation of state of QCD matter for temperatures near and above the quark-hadron transition (~165 MeV) is inferred within a Bayesian framework through the comparison of data from the Relativistic Heavy Ion Collider and from the Large Hadron Collider to theoretical models. State-of-the-art statistical techniques are applied to simultaneously analyze multiple classes of observables while varying 14 independent model parameters. Thus, the resulting posterior distribution over possible equations of state is consistent with results from lattice gauge theory.
Arnold, J.; Kosson, D.S.; Garrabrants, A.; Meeussen, J.C.L.; Sloot, H.A. van der
2013-02-15
A robust numerical solution of the nonlinear Poisson-Boltzmann equation for asymmetric polyelectrolyte solutions in discrete pore geometries is presented. Comparisons to the linearized approximation of the Poisson-Boltzmann equation reveal that the assumptions leading to linearization may not be appropriate for the electrochemical regime in many cementitious materials. Implications of the electric double layer on both partitioning of species and on diffusive release are discussed. The influence of the electric double layer on anion diffusion relative to cation diffusion is examined.
Charged annular disks and Reissner-Nordstroem type black holes from extremal dust
Lora-Clavijo, F. D.; Ospina-Henao, P. A.; Pedraza, J. F.
2010-10-15
We present the first analytical superposition of a charged black hole with an annular disk of extremal dust. In order to obtain the solutions, we first solve the Einstein-Maxwell field equations for sources that represent disklike configurations of matter in confomastatic spacetimes by assuming a functional dependence among the metric function, the electric potential, and an auxiliary function, which is taken as a solution of the Laplace equation. We then employ the Lord Kelvin inversion method applied to models of finite extension in order to obtain annular disks. The structures obtained extend to infinity, but their total masses are finite and all the energy conditions are satisfied. Finally, we observe that the extremal Reissner-Nordstroem black hole can be embedded into the center of the disks by adding a boundary term in the inversion.
Banik, Sarmistha [BITS Pilani, Hyderabad Campus, Hyderabad-500078 (India); Hempel, Matthias [Departement Physik, Universitt Basel, Klingelbergstrasse 82, 4056 Basel (Switzerland); Bandyopadhyay, Debades [Astroparticle Physics and Cosmology Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata-700064 (India)
2014-10-01
We develop new hyperon equation of state (EoS) tables for core-collapse supernova simulations and neutron stars. These EoS tables are based on a density-dependent relativistic hadron field theory where baryon-baryon interaction is mediated by mesons, using the parameter set DD2 for nucleons. Furthermore, light and heavy nuclei along with interacting nucleons are treated in the nuclear statistical equilibrium model of Hempel and Schaffner-Bielich which includes excluded volume effects. Of all possible hyperons, we consider only the contribution of ?s. We have developed two variants of hyperonic EoS tables: in the np?? case the repulsive hyperon-hyperon interaction mediated by the strange ? meson is taken into account, and in the np? case it is not. The EoS tables for the two cases encompass a wide range of densities (10{sup 12} to ?1 fm{sup 3}), temperatures (0.1 to 158.48 MeV), and proton fractions (0.01 to 0.60). The effects of ? hyperons on thermodynamic quantities such as free energy per baryon, pressure, or entropy per baryon are investigated and found to be significant at higher densities. The cold, ?-equilibrated EoS (with the crust included self-consistently) results in a 2.1 M {sub ?} maximum mass neutron star for the np?? case, whereas that for the np? case is 1.95 M {sub ?}. The np?? EoS represents the first supernova EoS table involving hyperons that is directly compatible with the recently measured 2 M {sub ?} neutron stars.
Group-invariant solutions of semilinear Schrdinger equations in multi-dimensions
Anco, Stephen C.; Feng, Wei; Department of Mathematics, Zhejiang University of Technology, Hangzhou 310014
2013-12-15
Symmetry group methods are applied to obtain all explicit group-invariant radial solutions to a class of semilinear Schrdinger equations in dimensions n ? 1. Both focusing and defocusing cases of a power nonlinearity are considered, including the special case of the pseudo-conformal power p = 4/n relevant for critical dynamics. The methods involve, first, reduction of the Schrdinger equations to group-invariant semilinear complex 2nd order ordinary differential equations (ODEs) with respect to an optimal set of one-dimensional point symmetry groups, and second, use of inherited symmetries, hidden symmetries, and conditional symmetries to solve each ODE by quadratures. Through Noether's theorem, all conservation laws arising from these point symmetry groups are listed. Some group-invariant solutions are found to exist for values of n other than just positive integers, and in such cases an alternative two-dimensional form of the Schrdinger equations involving an extra modulation term with a parameter m = 2?n ? 0 is discussed.
Equation of state for high explosives detonation products with explicit polar and ionic species
Bastea, S; Glaesemann, K R; Fried, L E
2006-06-28
We introduce a new thermodynamic theory for detonation products that includes polar and ionic species. The new formalism extends the domain of validity of the previously developed EXP6 equation of state library and opens the possibility of new applications. We illustrate the scope of the new approach on PETN detonation properties and water ionization models.
Derivation of quantum mechanics from the Boltzmann equation for the Planch aether
Winterberg, F.
1995-10-01
The Planck aether hypothesis assumes that space is densely filled with an equal number of locally interacting positive and negative Planck masses obeying an exactly nonrelativistic law of motion. The Planck masses can be described by a quantum mechanical two-component nonrelativistic operator field equation having the form of a two-component nonlinear Schroedinger equation, with a spectrum of quasiparticles obeying Lorentz invariance as a dynamic symmetry for energies small compared to the Planck energy. We show that quantum mechanics itself can be derived from the Newtonian mechanics of the Planck aether as an approximate solution of Boltzmann`s equation for the locally interacting positive and negative Planck masses, and that the validity of the nonrelativistic Schroedinger equation depends on Lorentz invariance as a dynamic symmetry. We also show how the many-body Schroedinger wave function can be factorized into a product of quasiparticles of the Planck aether with separable quantum potentials. Finally, we present a possible explanation of wave function collapse as a kind of enhanced gravitational collapse in the presence of the negative Planck masses.
The One and Two Loops Renormalization Group Equations in the Standard Model
Juarez W, S. Rebeca; Solis R, H. Gabriel; Kielanowski, P.
2006-01-06
In the context of the Standard Model (SM), we compare the analytical and the numerical solutions of the Renormalization Group Equations (RGE) for the relevant couplings to one and two loops. This information will be an important ingredient for the precise evaluation of boundary values on the physical Higgs Mass.
Cross, J. E.; Gregori, G.; Reville, B.
2014-11-01
We introduce the equations of magneto-quantum-radiative hydrodynamics. By rewriting them in a dimensionless form, we obtain a set of parameters that describe scale-dependent ratios of characteristic hydrodynamic quantities. We discuss how these dimensionless parameters relate to the scaling between astrophysical observations and laboratory experiments.
Neutron skin thickness and neutron star equations of state: a strong relationship
Menezes, D. P.; Avancini, S. S.; Marinelli, J. R.; Watanabe de Moraes, M. M.; Providencia, C.
2007-10-26
A density dependent hadronic model and a common parametrization of the non-linear Walecka model are used to obtain the lead neutron skin thickness through its proton and neutron density profiles. The neutron skin thickness is known to reflect the equation of state properties. A direct correlation between the neutron skin thickness and the slope of the symmetry energy is found.
On the solution of the continuity equation for precipitating electrons in solar flares
Emslie, A. Gordon; Holman, Gordon D.; Litvinenko, Yuri E. E-mail: gordon.d.holman@nasa.gov
2014-09-01
Electrons accelerated in solar flares are injected into the surrounding plasma, where they are subjected to the influence of collisional (Coulomb) energy losses. Their evolution is modeled by a partial differential equation describing continuity of electron number. In a recent paper, Dobranskis and Zharkova claim to have found an 'updated exact analytical solution' to this continuity equation. Their solution contains an additional term that drives an exponential decrease in electron density with depth, leading them to assert that the well-known solution derived by Brown, Syrovatskii and Shmeleva, and many others is invalid. We show that the solution of Dobranskis and Zharkova results from a fundamental error in the application of the method of characteristics and is hence incorrect. Further, their comparison of the 'new' analytical solution with numerical solutions of the Fokker-Planck equation fails to lend support to their result. We conclude that Dobranskis and Zharkova's solution of the universally accepted and well-established continuity equation is incorrect, and that their criticism of the correct solution is unfounded. We also demonstrate the formal equivalence of the approaches of Syrovatskii and Shmeleva and Brown, with particular reference to the evolution of the electron flux and number density (both differential in energy) in a collisional thick target. We strongly urge use of these long-established, correct solutions in future works.
Zhang, Zhongqiang; Yang, Xiu; Lin, Guang; Karniadakis, George Em
2013-03-01
We consider a piston with a velocity perturbed by Brownian motion moving into a straight tube filled with a perfect gas at rest. The shock generated ahead of the piston can be located by solving the one-dimensional Euler equations driven by white noise using the Stratonovich or Ito formulations. We approximate the Brownian motion with its spectral truncation and subsequently apply stochastic collocation using either sparse grid or the quasi-Monte Carlo (QMC) method. In particular, we first transform the Euler equations with an unsteady stochastic boundary into stochastic Euler equations over a fixed domain with a time-dependent stochastic source term. We then solve the transformed equations by splitting them up into two parts, i.e., a deterministic part and a stochastic part. Numerical results verify the StratonovichEuler and ItoEuler models against stochastic perturbation results, and demonstrate the efficiency of sparse grid and QMC for small and large random piston motions, respectively. The variance of shock location of the piston grows cubically in the case of white noise in contrast to colored noise reported in [1], where the variance of shock location grows quadratically with time for short times and linearly for longer times.
A new three-equation model for the CO{sub 2} laser
Stanghini, M.; Basso, M.; Genesio, R.; Tesi, A.; Meucci, R.; Ciofini, M.
1996-07-01
Three rate equations describing the single-mode CO{sub 2} laser dynamics are derived by applying the theory of linear filters to an improved four-level model. The model is studied in the case of periodic modulations of the losses and compared with the outcome of an experiment, revealing a good agreement.
FWAVE V1.0 a framework for finite difference wave equation modeling
Energy Science and Technology Software Center (OSTI)
2002-07-01
FWAVE provides a computation framework for the rapid prototyping and efficient use of finite difference wave equation solutions. The user provides single grid Fortran solver components that are integrated using opaque handles to C++ distributed data structures. Permits the scientific researcher to make of clusters and parallel computers by concentrating only on the numerical schemes.
SciCADE 95: International conference on scientific computation and differential equations
1995-12-31
This report consists of abstracts from the conference. Topics include algorithms, computer codes, and numerical solutions for differential equations. Linear and nonlinear as well as boundary-value and initial-value problems are covered. Various applications of these problems are also included.
The Layzer-Irvine equation in theories with non-minimal coupling between matter and curvature
Bertolami, O.; Gomes, C. E-mail: claudio.gomes@fc.up.pt
2014-09-01
We derive the Layzer-Irvine equation for alternative gravitational theories with non-minimal coupling between curvature and matter for an homogeneous and isotropic Universe. As an application, we study the case of Abell 586, a relaxed and spherically symmetric galaxy cluster, assuming some matter density profiles.
Glass, L.R.; Jones, T.D.; Easterly, C.E.; Walsh, P.J.
1990-10-01
It has been hypothesized that results from short-term bioassays will ultimately provide information that will be useful for human health hazard assessment. Historically, the validity of the short-term tests has been assessed using the framework of the epidemiologic/medical screens. In this context, the results of the carcinogen (long-term) bioassay is generally used as the standard. However, this approach is widely recognized as being biased and, because it employs qualitative data, cannot be used to assist in isolating those compounds which may represent a more significant toxicologic hazard than others. In contrast, the goal of this research is to address the problem of evaluating the utility of the short-term tests for hazard assessment using an alternative method of investigation. Chemicals were selected mostly from the list of carcinogens published by the International Agency for Research on Carcinogens (IARC); a few other chemicals commonly recognized as hazardous were included. Tumorigenicity and mutagenicity data on 52 chemicals were obtained from the Registry of Toxic Effects of Chemical Substances (RTECS) and were analyzed using a relative potency approach. The data were evaluated in a format which allowed for a comparison of the ranking of the mutagenic relative potencies of the compounds (as estimated using short-term data) vs. the ranking of the tumorigenic relative potencies (as estimated from the chronic bioassays). Although this was a preliminary investigation, it offers evidence that the short-term tests systems may be of utility in ranking the hazards represented by chemicals which may contribute to increased carcinogenesis in humans as a result of occupational or environmental exposures. 177 refs., 8 tabs.
Falder, J. T.; Stevens, J. A.; Jarvis, Matt J.; Bonfield, D. G.; Lacy, M.; Farrah, D.; Oliver, S.; Surace, J.; Mauduit, J.-C.; Gonzalez-Solares, E.; Afonso, J.; Cava, A.; Seymour, N.
2011-07-10
This paper presents a study of the environments of SDSS quasi-stellar objects (QSOs) in the Spitzer Extragalactic Representative Volume Survey (SERVS). We concentrate on the high-redshift QSOs as these have not been studied in large numbers with data of this depth before. We use the IRAC 3.6-4.5 {mu}m color of objects and ancillary r-band data to filter out as much foreground contamination as possible. This technique allows us to find a significant (>4{sigma}) overdensity of galaxies around QSOs in a redshift bin centered on z {approx} 2.0 and an (>2{sigma}) overdensity of galaxies around QSOs in a redshift bin centered on z {approx} 3.3. We compare our findings to the predictions of a semi-analytic galaxy formation model, based on the {Lambda}CDM MILLENNIUM simulation, and find for both redshift bins that the model predictions match well the source density we have measured from the SERVS data.
Laurie, M.; Fourrez, S.; Fuetterer, M. A.; Lapetite, J. M.
2011-07-01
During irradiation tests at high temperature, failure of commercial Inconel 600 sheathed thermocouples is commonly encountered. To understand and remedy this problem, out-of-pile tests were performed with thermocouples in carburizing atmospheres which can be assumed to be at least locally representative for High Temperature Reactors. The objective was to screen those thermocouples which would consecutively be used under irradiation. Two such screening tests have been performed with a set of thermocouples embedded in graphite (mainly conventional Type N thermocouples and thermocouples with innovative sheaths) in a dedicated furnace with helium flushing. Performance indicators such as thermal drift, insulation and loop resistance were monitored and compared to those from conventional Type N thermocouples. Several parameters were investigated: niobium sleeves, bending, thickness, sheath composition, temperature as well as the chemical environment. After the tests, Scanning Electron Microscopy (SEM) examinations were performed to analyze possible local damage in wires and in the sheath. The present paper describes the two experiments, summarizes results and outlines further work, in particular to further analyze the findings and to select suitable thermocouples for qualification under irradiation. (authors)
Herlemann, D. P. R.; Geissinger, O.; Ikeda-Ohtsubo, W.; Kunin, V.; Sun, H.; Lapidus, A.; Hugenholtz, P.; Brune, A.
2009-02-01
The candidate phylum Termite group 1 (TG1), is regularly 1 encountered in termite hindguts but is present also in many other habitats. Here we report the complete genome sequence (1.64 Mbp) of Elusimicrobium minutum strain Pei191{sup T}, the first cultured representative of the TG1 phylum. We reconstructed the metabolism of this strictly anaerobic bacterium isolated from a beetle larva gut and discuss the findings in light of physiological data. E. minutum has all genes required for uptake and fermentation of sugars via the Embden-Meyerhof pathway, including several hydrogenases, and an unusual peptide degradation pathway comprising transamination reactions and leading to the formation of alanine, which is excreted in substantial amounts. The presence of genes encoding lipopolysaccharide biosynthesis and the presence of a pathway for peptidoglycan formation are consistent with ultrastructural evidence of a Gram-negative cell envelope. Even though electron micrographs showed no cell appendages, the genome encodes many genes putatively involved in pilus assembly. We assigned some to a type II secretion system, but the function of 60 pilE-like genes remains unknown. Numerous genes with hypothetical functions, e.g., polyketide synthesis, non-ribosomal peptide synthesis, antibiotic transport, and oxygen stress protection, indicate the presence of hitherto undiscovered physiological traits. Comparative analysis of 22 concatenated single-copy marker genes corroborated the status of Elusimicrobia (formerly TG1) as a separate phylum in the bacterial domain, which was so far based only on 16S rRNA sequence analysis.
Narlesky, Joshua E.; Stroud, Mary Ann; Smith, Paul Herrick; Wayne, David M.; Mason, Richard E.; Worl, Laura A.
2013-02-15
The Surveillance and Monitoring Program is a joint Los Alamos National Laboratory/Savannah River Site effort funded by the Department of Energy-Environmental Management to provide the technical basis for the safe, long-term storage (up to 50 years) of over 6 metric tons of plutonium stored in over 5,000 DOE-STD-3013 containers at various facilities around the DOE complex. The majority of this material is plutonium that is surplus to the nuclear weapons program, and much of it is destined for conversion to mixed oxide fuel for use in US nuclear power plants. The form of the plutonium ranges from relatively pure metal and oxide to very impure oxide. The performance of the 3013 containers has been shown to depend on moisture content and on the levels, types and chemical forms of the impurities. The oxide materials that present the greatest challenge to the storage container are those that contain chloride salts. Other common impurities include oxides and other compounds of calcium, magnesium, iron, and nickel. Over the past 15 years the program has collected a large body of experimental data on 54 samples of plutonium, with 53 chosen to represent the broader population of materials in storage. This paper summarizes the characterization data, moisture analysis, particle size, surface area, density, wattage, actinide composition, trace element impurity analysis, and shelf life surveillance data and includes origin and process history information. Limited characterization data on fourteen nonrepresentative samples is also presented.
Harris, Scott H.; Johnson, Joel A.; Neiswanger, Jeffery R.; Twitchell, Kevin E.
2004-03-09
The present invention includes systems configured to distribute a telephone call, communication systems, communication methods and methods of routing a telephone call to a customer service representative. In one embodiment of the invention, a system configured to distribute a telephone call within a network includes a distributor adapted to connect with a telephone system, the distributor being configured to connect a telephone call using the telephone system and output the telephone call and associated data of the telephone call; and a plurality of customer service representative terminals connected with the distributor and a selected customer service representative terminal being configured to receive the telephone call and the associated data, the distributor and the selected customer service representative terminal being configured to synchronize, application of the telephone call and associated data from the distributor to the selected customer service representative terminal.
Energy Science and Technology Software Center (OSTI)
2014-06-01
ARKode is part of a software family called SUNDIALS: SUite of Nonlinear and Differential/ALgebraic equation Solvers [1]. The ARKode solver library provides an adaptive-step time integration package for stiff, nonstiff and multi-rate systems of ordinary differential equations (ODEs) using Runge Kutta methods [2].
Fast multiscale Gaussian beam methods for wave equations in bounded convex domains
Bao, Gang; Department of Mathematics, Michigan State University, East Lansing, MI 48824 ; Lai, Jun; Qian, Jianliang
2014-03-15
Motivated by fast multiscale Gaussian wavepacket transforms and multiscale Gaussian beam methods which were originally designed for pure initial-value problems of wave equations, we develop fast multiscale Gaussian beam methods for initial boundary value problems of wave equations in bounded convex domains in the high frequency regime. To compute the wave propagation in bounded convex domains, we have to take into account reflecting multiscale Gaussian beams, which are accomplished by enforcing reflecting boundary conditions during beam propagation and carrying out suitable reflecting beam summation. To propagate multiscale beams efficiently, we prove that the ratio of the squared magnitude of beam amplitude and the beam width is roughly conserved, and accordingly we propose an effective indicator to identify significant beams. We also prove that the resulting multiscale Gaussian beam methods converge asymptotically. Numerical examples demonstrate the accuracy and efficiency of the method.
On lower bounds for possible blow-up solutions to the periodic Navier-Stokes equation
Cortissoz, Jean C. Montero, Julio A. Pinilla, Carlos E.
2014-03-15
We show a new lower bound on the H{sup .3/2} (T{sup 3}) norm of a possible blow-up solution to the Navier-Stokes equation, and also comment on the extension of this result to the whole space. This estimate can be seen as a natural limiting result for Leray's blow-up estimates in L{sup p}(R{sup 3}), 3 < p < ?. We also show a lower bound on the blow-up rate of a possible blow-up solution of the Navier-Stokes equation in H{sup .5/2} (T{sup 3}), and give the corresponding extension to the case of the whole space.
Talamo, Alberto
2013-05-01
This study presents three numerical algorithms to solve the time dependent neutron transport equation by the method of the characteristics. The algorithms have been developed taking into account delayed neutrons and they have been implemented into the novel MCART code, which solves the neutron transport equation for two-dimensional geometry and an arbitrary number of energy groups. The MCART code uses regular mesh for the representation of the spatial domain, it models up-scattering, and takes advantage of OPENMP and OPENGL algorithms for parallel computing and plotting, respectively. The code has been benchmarked with the multiplication factor results of a Boiling Water Reactor, with the analytical results for a prompt jump transient in an infinite medium, and with PARTISN and TDTORT results for cross section and source transients. The numerical simulations have shown that only two numerical algorithms are stable for small time steps.
Deterministic proton transport solving a one dimensional Fokker-Planck equation
Marr, D.; Prael, R.; Adams, K.; Alcouffe, R.
1997-10-01
The transport of protons through matter is characterized by many interactions which cause small deflections and slight energy losses. The few which are catastrophic or cause large angle scattering can be viewed as extinction for many applications. The transport of protons at this level of approximation can be described by a Fokker Planck Equation. This equation is solved using a deterministic multigroup differencing scheme with a highly resolved set of discrete ordinates centered around the beam direction which is adequate to properly account for deflections and energy losses due to multiple Coulomb scattering. Comparisons with LAHET for a large variety of problems ranging from 800 MeV protons on a copper step wedge to 10 GeV protons on a sandwich of material are presented. The good agreement with the Monte Carlo code shows that the solution method is robust and useful for approximate solutions of selected proton transport problems.
Manzini, Gianmarco; Cangiani, Andrea; Sutton, Oliver
2014-10-02
This document describes the conforming formulations for virtual element approximation of the convection-reaction-diffusion equation with variable coefficients. Emphasis is given to construction of the projection operators onto polynomial spaces of appropriate order. These projections make it possible the virtual formulation to achieve any order of accuracy. We present the construction of the internal and the external formulation. The difference between the two is in the way the projection operators act on the derivatives (laplacian, gradient) of the partial differential equation. For the diffusive regime we prove the well-posedness of the external formulation and we derive an estimate of the approximation error in the H^{1}-norm. For the convection-dominated case, the streamline diffusion stabilization (aka SUPG) is also discussed.
Dynamical mass generation in unquenched QED using the Dyson-Schwinger equations
Kızılersü, Ayse; Sizer, Tom; Pennington, Michael R.; Williams, Anthony G.; Williams, Richard
2015-03-13
We present a comprehensive numerical study of dynamical mass generation for unquenched QED in four dimensions, in the absence of four-fermion interactions, using the Dyson-Schwinger approach. We begin with an overview of previous investigations of criticality in the quenched approximation. To this we add an analysis using a new fermion-antifermion-boson interaction ansatz, the Kizilersu-Pennington (KP) vertex, developed for an unquenched treatment. After surveying criticality in previous unquenched studies, we investigate the performance of the KP vertex in dynamical mass generation using a renormalized fully unquenched system of equations. This we compare with the results for two hybrid vertices incorporating the Curtis-Pennington vertex in the fermion equation. We conclude that the KP vertex is as yet incomplete, and its relative gauge-variance is due to its lack of massive transverse components in its design.
A fast, high-order solver for the GradShafranov equation
Pataki, Andras; Cerfon, Antoine J.; Freidberg, Jeffrey P.; Greengard, Leslie; ONeil, Michael
2013-06-15
We present a new fast solver to calculate fixed-boundary plasma equilibria in toroidally axisymmetric geometries. By combining conformal mapping with Fourier and integral equation methods on the unit disk, we show that high-order accuracy can be achieved for the solution of the equilibrium equation and its first and second derivatives. Smooth arbitrary plasma cross-sections as well as arbitrary pressure and poloidal current profiles are used as initial data for the solver. Equilibria with large Shafranov shifts can be computed without difficulty. Spectral convergence is demonstrated by comparing the numerical solution with a known exact analytic solution. A fusion-relevant example of an equilibrium with a pressure pedestal is also presented.
Vortices at the magnetic equator generated by hybrid Alfvn resonant waves
Hiraki, Yasutaka
2015-01-15
We performed three-dimensional magnetohydrodynamic simulations of shear Alfvn waves in a full field line system with magnetosphere-ionosphere coupling and plasma non-uniformities. Feedback instability of the Alfvn resonant modes showed various nonlinear features under the field line cavities: (i) a secondary flow shear instability occurs at the magnetic equator, (ii) trapping of the ionospheric Alfvn resonant modes facilitates deformation of field-aligned current structures, and (iii) hybrid Alfvn resonant modes grow to cause vortices and magnetic oscillations around the magnetic equator. Essential features in the initial brightening of auroral arc at substorm onsets could be explained by the dynamics of Alfvn resonant modes, which are the nature of the field line system responding to a background rapid change.
Jin, Jinshuang; Li, Jun; Liu, Yu; Li, Xin-Qi; Yan, YiJing
2014-06-28
Beyond the second-order Born approximation, we propose an improved master equation approach to quantum transport under self-consistent Born approximation. The basic idea is to replace the free Green's function in the tunneling self-energy diagram by an effective reduced propagator under the Born approximation. This simple modification has remarkable consequences. It not only recovers the exact results for quantum transport through noninteracting systems under arbitrary voltages, but also predicts the challenging nonequilibrium Kondo effect. Compared to the nonequilibrium Green's function technique that formulates the calculation of specific correlation functions, the master equation approach contains richer dynamical information to allow more efficient studies for such as the shot noise and full counting statistics.
Low-dimensional weakly interacting Bose gases: Nonuniversal equations of state
Astrakharchik, G. E.; Boronat, J.; Mazzanti, F.; Kurbakov, I. L.; Lozovik, Yu. E.
2010-01-15
The zero-temperature equation of state is analyzed in low-dimensional bosonic systems. We propose to use the concept of energy-dependent s-wave scattering length for obtaining estimations of nonuniversal terms in the energy expansion. We test this approach by making a comparison to exactly solvable one-dimensional problems and find that the generated terms have the correct structure. The applicability to two-dimensional systems is analyzed by comparing with results of Monte Carlo simulations. The prediction for the nonuniversal behavior is qualitatively correct and the densities, at which the deviations from the universal equation of state become visible, are estimated properly. Finally, the possibility of observing the nonuniversal terms in experiments with trapped gases is also discussed.
Observational constraints on dark energy with a fast varying equation of state
Felice, Antonio De; Nesseris, Savvas
2012-05-01
We place observational constraints on models with the late-time cosmic acceleration based on a number of parametrizations allowing fast transitions for the equation of state of dark energy. In addition to the model of Linder and Huterer where the dark energy equation of state w monotonically grows or decreases in time, we propose two new parametrizations in which w has an extremum. We carry out the likelihood analysis with the three parametrizations by using the observational data of supernovae type Ia, cosmic microwave background, and baryon acoustic oscillations. Although the transient cosmic acceleration models with fast transitions can give rise to the total chi square smaller than that in the ?-Cold-Dark-Matter (?CDM) model, these models are not favored over ?CDM when one uses the Akaike information criterion which penalizes the extra degrees of freedom present in the parametrizations.
Waltz, J.; Canfield, T.R.; Morgan, N.R.; Risinger, L.D.; Wohlbier, J.G.
2014-06-15
We present a set of manufactured solutions for the three-dimensional (3D) Euler equations. The purpose of these solutions is to allow for code verification against true 3D flows with physical relevance, as opposed to 3D simulations of lower-dimensional problems or manufactured solutions that lack physical relevance. Of particular interest are solutions with relevance to Inertial Confinement Fusion (ICF) capsules. While ICF capsules are designed for spherical symmetry, they are hypothesized to become highly 3D at late time due to phenomena such as Rayleigh–Taylor instability, drive asymmetry, and vortex decay. ICF capsules also involve highly nonlinear coupling between the fluid dynamics and other physics, such as radiation transport and thermonuclear fusion. The manufactured solutions we present are specifically designed to test the terms and couplings in the Euler equations that are relevant to these phenomena. Example numerical results generated with a 3D Finite Element hydrodynamics code are presented, including mesh convergence studies.
Equations of state and transport properties of mixtures in the warm dense regime
Hou, Yong; Dai, Jiayu; Kang, Dongdong; Ma, Wen; Yuan, Jianmin
2015-02-15
We have performed average-atom molecular dynamics to simulate the CH and LiH mixtures in the warm dense regime, and obtained equations of state and the ionic transport properties. The electronic structures are calculated by using the modified average-atom model, which have included the broadening of energy levels, and the ion-ion pair potentials of mixtures are constructed based on the temperature-dependent density functional theory. The ionic transport properties, such as ionic diffusion and shear viscosity, are obtained through the ionic velocity correlation functions. The equations of state and transport properties for carbon, hydrogen and lithium, hydrogen mixtures in a wide region of density and temperature are calculated. Through our computing the average ionization degree, average ion-sphere diameter and transition properties in the mixture, it is shown that transport properties depend not only on the ionic mass but also on the average ionization degree.
Generalized conditional symmetries and related solutions of the Grad-Shafranov equation
Cimpoiasu, Rodica
2014-04-15
The generalized conditional symmetry (GCS) method is applied to a specific case of the Grad–Shafranov (GS) equation, in cylindrical geometry assuming the existence of an axial symmetry. We investigate the conditions that yield the GS equation admitting a special class of second-order GCSs. The determining system for the unknown arbitrary functions is solved in several special cases and new exact solutions, including solitary waves, different in form and structure from the ones obtained using other nonclassical symmetry methods, are pointed out. Several plots of the level sets or flux surfaces of the new solutions as well as surfaces with vanishing flow are displayed. The obtained solutions can be useful for studying plasma equilibrium, transport phenomena, and magnetohydrodynamic stability.
Dynamical mass generation in unquenched QED using the Dyson-Schwinger equations
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Kızılersü, Ayse; Sizer, Tom; Pennington, Michael R.; Williams, Anthony G.; Williams, Richard
2015-03-13
We present a comprehensive numerical study of dynamical mass generation for unquenched QED in four dimensions, in the absence of four-fermion interactions, using the Dyson-Schwinger approach. We begin with an overview of previous investigations of criticality in the quenched approximation. To this we add an analysis using a new fermion-antifermion-boson interaction ansatz, the Kizilersu-Pennington (KP) vertex, developed for an unquenched treatment. After surveying criticality in previous unquenched studies, we investigate the performance of the KP vertex in dynamical mass generation using a renormalized fully unquenched system of equations. This we compare with the results for two hybrid vertices incorporating themore » Curtis-Pennington vertex in the fermion equation. We conclude that the KP vertex is as yet incomplete, and its relative gauge-variance is due to its lack of massive transverse components in its design.« less
The Equations of Motion of Compact Binaries in the Neighborhood of Supermassive Black Hole
Gorbatsievich, Alexander; Bobrik, Alexey
2010-03-24
By the use of Einstein-Infeld-Hoffmann method, the equations of motion of a binary star system in the field of a supermassive black hole are derived. In spite of the fact that the motion of a binary system as a whole can be relativistic or even ultra-relativistic with respect to the supermassive black hole, it is shown, that under the assumption of non-relativistic relative motion of the stars in binary system, the motion of the binary system as a whole satisfies the Mathisson-Papapetrou equations with additional terms depending on quadrupole moments. Exemplary case of ultrarelativistic motion of a binary neutron star in the vicinity of non-rotating black hole is considered. It it shown that the motion of binary's center of mass may considerably differ from geodesic motion.
Grating formation by a high power radio wave in near-equator ionosphere
Singh, Rohtash; Sharma, A. K.; Tripathi, V. K.
2011-11-15
The formation of a volume grating in the near-equator regions of ionosphere due to a high power radio wave is investigated. The radio wave, launched from a ground based transmitter, forms a standing wave pattern below the critical layer, heating the electrons in a space periodic manner. The thermal conduction along the magnetic lines of force inhibits the rise in electron temperature, limiting the efficacy of heating to within a latitude of few degrees around the equator. The space periodic electron partial pressure leads to ambipolar diffusion creating a space periodic density ripple with wave vector along the vertical. Such a volume grating is effective to cause strong reflection of radio waves at a frequency one order of magnitude higher than the maximum plasma frequency in the ionosphere. Linearly mode converted plasma wave could scatter even higher frequency radio waves.
The quantum equations of state of plasma under the influence of a weak magnetic field
Hussein, N. A.; Eisa, D. A.; Eldin, M. G.
2012-05-15
The aim of this paper is to calculate the magnetic quantum equations of state of plasma, the calculation is based on the magnetic binary Slater sum in the case of low density. We consider only the thermal equilibrium plasma in the case of n{lambda}{sub ab}{sup 3} Much-Less-Than 1, where {lambda}{sub ab}{sup 2}=( Planck-Constant-Over-Two-Pi {sup 2}/m{sub ab}KT) is the thermal De Broglie wave length between two particles. The formulas contain the contributions of the magnetic field effects. Using these results we compute the magnetization and the magnetic susceptibility. Our equation of state is compared with others.
Non-perturbative effects for the Quark-Gluon Plasma equation of state
Begun, V. V. Gorenstein, M. I. Mogilevsky, O. A.
2012-07-15
The non-perturbative effects for the Quark-Gluon Plasma (QGP) equation of state (EoS) are considered. The modifications of the bag model EoS are constructed to satisfy the main qualitative features observed for the QGP EoS in the lattice QCD calculations. A quantitative comparison with the lattice results is done for the SU(3) gluon plasma and for the QGP with dynamical quarks. Our analysis advocates a negative value of the bag constant B.
CONTRACTOR REPORT SAND97-2426 Unlimited Release UC-705 Penetration Equations
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CONTRACTOR REPORT SAND97-2426 Unlimited Release * UC-705 Penetration Equations C. W. Young Applied Research Associates, Inc. 4300 San Mateo Blvd. NE, Suite A-220 Albuquerque NM 871 10 Prepared by Sandia National Laboratories Albuquerque, New Mexico 87185 and Livermore, California 94550 Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under Contract DE-AC04-94AL85000. Approved for public release; distribution
SCIENCE ON SATURDAY- "Disastrous Equations: The Role of Mathematics in
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Understanding Tsunami" | Princeton Plasma Physics Lab 26, 2013, 9:30am Science On Saturday MBG Auditorium SCIENCE ON SATURDAY- "Disastrous Equations: The Role of Mathematics in Understanding Tsunami" Professor J. Douglas Wright, Associate Professor Department of Mathematics, Drexel University Presentation: PDF icon SOS26JAN2013_JDWright.pdf Science on Saturday is a series of lectures given by scientists, mathematicians, and other professionals involved in cutting-edge
Samsonov, B.F.
1995-09-01
It is proven that the well-known nonlocal (i.e., based on integral transformations) methods of generating accurately solvable potentials of the one-dimensional steady Schroedinger equation are equivalent to multiple use of the local (i.e., based on a differential transformation) method known as the Darboux transformation. New accurately solvable potentials with a hydrogen-like spectrum are obtained, and several functions of the lowest states of the discrete spectrum are presented.
Jiang, Yan-Fei; Stone, James M.; Davis, Shane W.
2014-07-01
We describe a new algorithm for solving the coupled frequency-integrated transfer equation and the equations of magnetohydrodynamics in the regime that light-crossing time is only marginally shorter than dynamical timescales. The transfer equation is solved in the mixed frame, including velocity-dependent source terms accurate to O(v/c). An operator split approach is used to compute the specific intensity along discrete rays, with upwind monotonic interpolation used along each ray to update the transport terms, and implicit methods used to compute the scattering and absorption source terms. Conservative differencing is used for the transport terms, which ensures the specific intensity (as well as energy and momentum) are conserved along each ray to round-off error. The use of implicit methods for the source terms ensures the method is stable even if the source terms are very stiff. To couple the solution of the transfer equation to the MHD algorithms in the ATHENA code, we perform direct quadrature of the specific intensity over angles to compute the energy and momentum source terms. We present the results of a variety of tests of the method, such as calculating the structure of a non-LTE atmosphere, an advective diffusion test, linear wave convergence tests, and the well-known shadow test. We use new semi-analytic solutions for radiation modified shocks to demonstrate the ability of our algorithm to capture the effects of an anisotropic radiation field accurately. Since the method uses explicit differencing of the spatial operators, it shows excellent weak scaling on parallel computers.
Viscosity Solutions of HJB Equations with Unbounded Data and Characteristic Points
Motta, Monica
2003-12-15
We study a class of infinite horizon and exit-time control problems for nonlinear systems with unbounded data using the dynamic programming approach. We prove local optimality principles for viscosity super- and subsolutions of degenerate Hamilton-Jacobi equations in a very general setting. We apply these results to characterize the (possibly multiple) discontinuous solutions of Dirichlet and free boundary value problems as suitable value functions for the above-mentioned control problems.
Nonlinear periodic waves solutions of the nonlinear self-dual network equations
Laptev, Denis V. Bogdan, Mikhail M.
2014-04-15
The new classes of periodic solutions of nonlinear self-dual network equations describing the breather and soliton lattices, expressed in terms of the Jacobi elliptic functions have been obtained. The dependences of the frequencies on energy have been found. Numerical simulations of soliton lattice demonstrate their stability in the ideal lattice and the breather lattice instability in the dissipative lattice. However, the lifetime of such structures in the dissipative lattice can be extended through the application of ac driving terms.
Dvirny, A. I.; Slyn'ko, V. I. E-mail: vitstab@ukr.net
2014-06-01
Inverse theorems to Lyapunov's direct method are established for quasihomogeneous systems of differential equations with impulsive action. Conditions for the existence of Lyapunov functions satisfying typical bounds for quasihomogeneous functions are obtained. Using these results, we establish conditions for an equilibrium of a nonlinear system with impulsive action to be stable, using the properties of a quasihomogeneous approximation to the system. The results are illustrated by an example of a large-scale system with homogeneous subsystems. Bibliography: 30 titles. (paper)
Non-homogeneous solutions of a Coulomb Schrdinger equation as basis set for scattering problems
Del Punta, J. A.; Ambrosio, M. J.; Gasaneo, G.; Zaytsev, S. A.; Ancarani, L. U.
2014-05-15
We introduce and study two-body Quasi Sturmian functions which are proposed as basis functions for applications in three-body scattering problems. They are solutions of a two-body non-homogeneous Schrdinger equation. We present different analytic expressions, including asymptotic behaviors, for the pure Coulomb potential with a driven term involving either Slater-type or Laguerre-type orbitals. The efficiency of Quasi Sturmian functions as basis set is numerically illustrated through a two-body scattering problem.
Argonne OutLoud: Changing the bio-energy equation (April 12, 2012) |
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Argonne National Laboratory Changing the bio-energy equation (April 12, 2012) Share Description Argonne OutLoud public lecture series. Episode 1: Argonomist Cristina Negri talks about phytoremediation for polluted soil and water. Speakers Cristina Negri Duration 00:55:11 Topic Community Education Outreach Environment Environmental science & technology Land reclamation Water quality Video ID http://youtu.be/vlMUJOs4vh0 Credit Argonne National Laboratory Cristina Negri
THE GENERAL RELATIVISTIC EQUATIONS OF RADIATION HYDRODYNAMICS IN THE VISCOUS LIMIT
Coughlin, Eric R.; Begelman, Mitchell C. E-mail: mitch@jila.colorado.edu
2014-12-20
We present an analysis of the general relativistic Boltzmann equation for radiation, appropriate to the case where particles and photons interact through Thomson scattering, and derive the radiation energy-momentum tensor in the diffusion limit with viscous terms included. Contrary to relativistic generalizations of the viscous stress tensor that appear in the literature, we find that the stress tensor should contain a correction to the comoving energy density proportional to the divergence of the four-velocity, as well as a finite bulk viscosity. These modifications are consistent with the framework of radiation hydrodynamics in the limit of large optical depth, and do not depend on thermodynamic arguments such as the assignment of a temperature to the zeroth-order photon distribution. We perform a perturbation analysis on our equations and demonstrate that as long as the wave numbers do not probe scales smaller than the mean free path of the radiation, the viscosity contributes only decaying, i.e., stable, corrections to the dispersion relations. The astrophysical applications of our equations, including jets launched from super-Eddington tidal disruption events and those from collapsars, are discussed and will be considered further in future papers.
Unified Einstein-Virasoro Master Equation in the General Non-Linear Sigma Model
Boer, J. de; Halpern, M.B.
1996-06-05
The Virasoro master equation (VME) describes the general affine-Virasoro construction $T=L^abJ_aJ_b+iD^a \\dif J_a$ in the operator algebra of the WZW model, where $L^ab$ is the inverse inertia tensor and $D^a $ is the improvement vector. In this paper, we generalize this construction to find the general (one-loop) Virasoro construction in the operator algebra of the general non-linear sigma model. The result is a unified Einstein-Virasoro master equation which couples the spacetime spin-two field $L^ab$ to the background fields of the sigma model. For a particular solution $L_G^ab$, the unified system reduces to the canonical stress tensors and conventional Einstein equations of the sigma model, and the system reduces to the general affine-Virasoro construction and the VME when the sigma model is taken to be the WZW action. More generally, the unified system describes a space of conformal field theories which is presumably much larger than the sum of the general affine-Virasoro construction and the sigma model with its canonical stress tensors. We also discuss a number of algebraic and geometrical properties of the system, including its relation to an unsolved problem in the theory of $G$-structures on manifolds with torsion.
Discontinuous Galerkin solution of the Navier-Stokes equations on deformable domains
Persson, P.-O.; Bonet, J.; Peraire, J.
2009-01-13
We describe a method for computing time-dependent solutions to the compressible Navier-Stokes equations on variable geometries. We introduce a continuous mapping between a fixed reference configuration and the time varying domain, By writing the Navier-Stokes equations as a conservation law for the independent variables in the reference configuration, the complexity introduced by variable geometry is reduced to solving a transformed conservation law in a fixed reference configuration, The spatial discretization is carried out using the Discontinuous Galerkin method on unstructured meshes of triangles, while the time integration is performed using an explicit Runge-Kutta method, For general domain changes, the standard scheme fails to preserve exactly the free-stream solution which leads to some accuracy degradation, especially for low order approximations. This situation is remedied by adding an additional equation for the time evolution of the transformation Jacobian to the original conservation law and correcting for the accumulated metric integration errors. A number of results are shown to illustrate the flexibility of the approach to handle high order approximations on complex geometries.
Gao, Yang; Fu, Joshua S.; Drake, John B.; Lamarque, J.-F.; Liu, Yang
2013-09-27
Dynamical downscaling was applied in this study to link the global climate-chemistry model Community Atmosphere Model (CAM-Chem) with the regional models: Weather Research and Forecasting (WRF) Model and Community Multi-scale Air Quality (CMAQ). Two Representative Concentration Pathway (RCP) scenarios (RCP 4.5 and RCP 8.5) were used to evaluate the climate impact on ozone concentrations in 2050s. Ozone concentrations in the lower-mid troposphere (surface to ~300 hPa), from mid- to high latitudes in the Northern Hemisphere (NH), show decreasing trends in RCP 4.5 between 2000s and 2050s, with the largest decrease of 4-10 ppbv occurring in the summer and the fall; and increasing trends (2-12 ppbv) in RCP 8.5 resulting from the increased methane emissions. In RCP 8.5, methane emissions increase by ~60% by the end of 2050s, accounting for more than 90% of ozone increases in summer and fall, and 60-80% in spring and winter. Under the RCP 4.5 scenario, in the summer when photochemical reactions are the most active, the large ozone precursor emissions reduction leads to the greatest decrease of downscaled surface ozone concentrations, ranging from 6 to 10 ppbv. However, a few major cities show ozone increases of 3 to 7 ppbv due to weakened NO titration. Under the RCP 8.5 scenario, in winter, downscaled ozone concentrations increase across nearly the entire continental US in winter, ranging from 3 to 10 ppbv due to increased methane emissions and enhanced stratosphere-troposphere exchange (STE). More intense heat waves are projected to occur by the end of 2050s in RCP 8.5, leading to more than 8 ppbv of the maximum daily 8-hour daily average (MDA8) ozone during the heat wave days than other days; this indicates the dramatic impact heat waves exert on high frequency ozone events.
Kyle, G. Page; Mueller, C.; Calvin, Katherine V.; Thomson, Allison M.
2014-02-28
This study assesses how climate impacts on agriculture may change the evolution of the agricultural and energy systems in meeting the end-of-century radiative forcing targets of the Representative Concentration Pathways (RCPs). We build on the recently completed ISI-MIP exercise that has produced global gridded estimates of future crop yields for major agricultural crops using climate model projections of the RCPs from the Coupled Model Intercomparison Project Phase 5 (CMIP5). For this study we use the bias-corrected outputs of the HadGEM2-ES climate model as inputs to the LPJmL crop growth model, and the outputs of LPJmL to modify inputs to the GCAM integrated assessment model. Our results indicate that agricultural climate impacts generally lead to an increase in global cropland, as compared with corresponding emissions scenarios that do not consider climate impacts on agricultural productivity. This is driven mostly by negative impacts on wheat, rice, other grains, and oil crops. Still, including agricultural climate impacts does not significantly increase the costs or change the technological strategies of global, whole-system emissions mitigation. In fact, to meet the most aggressive climate change mitigation target (2.6 W/m2 in 2100), the net mitigation costs are slightly lower when agricultural climate impacts are considered. Key contributing factors to these results are (a) low levels of climate change in the low-forcing scenarios, (b) adaptation to climate impacts, simulated in GCAM through inter-regional shifting in the production of agricultural goods, and (c) positive average climate impacts on bioenergy crop yields.
A Vorticity-Divergence Global Semi-Lagrangian Spectral Model for the Shallow Water Equations
Drake, JB
2001-11-30
The shallow water equations modeling flow on a sphere are useful for the development and testing of numerical algorithms for atmospheric climate and weather models. A new formulation of the shallow water equations is derived which exhibits an advective form for the vorticity and divergence. This form is particularly well suited for numerical computations using a semi-Lagrangian spectral discretization. A set of test problems, standard for the shallow water equations on a sphere, are solved and results compared with an Eulerian spectral model. The semi-Lagrangian transport method was introduced into atmospheric modeling by Robert, Henderson, and Turnbull. A formulation based on a three time level integration scheme in conjunction with a finite difference spatial discretization was studied by Ritchie. Two time level grid point schemes were derived by Bates et al. Staniforth and Cote survey developments of the application of semi-Lagrangian transport (SLT) methods for shallow water models and for numerical weather prediction. The spectral (or spherical harmonic transform) method when combined with a SLT method is particularly effective because it allows for long time steps avoiding the Courant-Friedrichs-Lewy (CFL) restriction of Eulerian methods, while retaining accurate (spectral) treatment of the spatial derivatives. A semi-implicit, semi-Lagrangian formulation with spectral spatial discretization is very effective because the Helmholz problem arising from the semi-implicit time integration can be solved cheaply in the course of the spherical harmonic transform. The combination of spectral, semi-Lagrangian transport with a semi-implicit time integration schemes was first proposed by Ritchie. A advective formulation using vorticity and divergence was introduced by Williamson and Olson. They introduce the vorticity and divergence after the application of the semi-Lagrangian discretization. The semi-Lagrangian formulation of Williamson and Olson and Bates et al. has the property that the metric terms of the advective form are treated discretely requiring a delicate spherical vector addition of terms at the departure point and arrival point. In their formulation, the metric terms associated with the advection operator do not appear explicitly. The spherical geometry associated with the combination of vector quantities at arrival and departure points treats the metric terms and is derived in Bates et al. The formulation derived in this paper avoids this vector addition. It is possible to do this because our formulation is based entirely on a scalar, advective form of the momentum equations. This new form is made possible by the generalization of a vector identity to spherical geometry. In Section 2 the standard form of the shallow water equations in spherical geometry are given. Section 3 presents the vector identities needed to derive an advective form of the vorticity and divergence equations. The semi-implicit time integration and semi-Lagrangian transport method are described in Section 4. The SLT interpolation scheme is described in Section 5. Section 6 completes the development of the discrete model with the description of the semi-implicit spectral equations. A discussion of results on several standard test problems is contained in Section 7.
Dixon, Robert L.; Boone, John M.; Kraft, Robert A.
2014-11-01
Purpose: With the increasing clinical use of shift-variant CT protocols involving tube current modulation (TCM), variable pitch or pitch modulation (PM), and variable aperture a(t), the interpretation of the scanner-reported CTDI{sub vol} is called into question. This was addressed for TCM in their previous paper published by Dixon and Boone [Med. Phys. 40, 111920 (14pp.) (2013)] and is extended to PM and concurrent TCM/PM as well as variable aperture in this work. Methods: Rigorous convolution equations are derived to describe the accumulated dose distributions for TCM, PM, and concurrent TCM/PM. A comparison with scanner-reported CTDI{sub vol} formulae clearly identifies the source of their differences with the traditional CTDI{sub vol}. Dose distribution simulations using the convolution are provided for a variety of TCM and PM scenarios including a helical shuttle used for perfusion studies (as well as constant mA)all having the same scanner-reported CTDI{sub vol}. These new convolution simulations for TCM are validated by comparison with their previous discrete summations. Results: These equations show that PM is equivalent to TCM if the pitch variation p(z) is proportional to 1/i(z), where i(z) is the local tube current. The simulations show that the local dose at z depends only weakly on the local tube current i(z) or local pitch p(z) due to scatter from all other locations along z, and that the local CTDI{sub vol}(z) or CTDI{sub vol} per slice do not represent a local dose but rather only a relative i(z) or p(z). The CTDI-paradigm does not apply to shift-variant techniques and the scanner-reported CTDI{sub vol} for the same lacks physical significance and relevance. Conclusions: While the traditional CTDI{sub vol} at constant tube current and pitch conveys useful information (the peak dose at the center of the scan length), CTDI{sub vol} for shift-variant techniques (TCM or PM) conveys no useful information about the associated dose distribution it purportedly represents. On the other hand, the total energy absorbed E (integral dose) as well as its surrogate DLP remain robust (invariant) with respect to shift-variance, depending only on the total mAs = ?i?t{sub 0} accumulated during the total beam-on time t{sub 0} and aperture a, where ?i? is the average current.
Wang, Y.
2013-07-01
Nonlinear diffusion acceleration (NDA) can improve the performance of a neutron transport solver significantly especially for the multigroup eigenvalue problems. The high-order transport equation and the transport-corrected low-order diffusion equation form a nonlinear system in NDA, which can be solved via a Picard iteration. The consistency of the correction of the low-order equation is important to ensure the stabilization and effectiveness of the iteration. It also makes the low-order equation preserve the scalar flux of the high-order equation. In this paper, the consistent correction for a particular discretization scheme, self-adjoint angular flux (SAAF) formulation with discrete ordinates method (S{sub N}) and continuous finite element method (CFEM) is proposed for the multigroup neutron transport equation. Equations with the anisotropic scatterings and a void treatment are included. The Picard iteration with this scheme has been implemented and tested with RattleS{sub N}ake, a MOOSE-based application at INL. Convergence results are presented. (authors)
Broader source: Energy.gov [DOE]
This memorandum provides an overview of the meeting between representatives of the American Public Gas Association (APGA) and of the Department of Energy (DOE). Present for APGA were Dave Schryver...
Ammar H Hakim
2011-10-20
In this Phase I project we have extended the BOUT++ code to solve edge fluid equations. We added a simple neutral fluid model, created a mesh generator as well as collected a set of difficult test problems for benchmarking edge codes. The work in this project should be useful as a starting point to build a complete set of edge fluid equations in BOUT++ that would enhance its ability to not only perform edge turbulence calculations, but also allow the coupled transport-turbulence equations evolved in an efficient manner.
The Equation of State of LLM-105 (2,6-diamino-3,5-dinitropyrazine-1-oxide)
Office of Scientific and Technical Information (OSTI)
(Conference) | SciTech Connect Conference: The Equation of State of LLM-105 (2,6-diamino-3,5-dinitropyrazine-1-oxide) Citation Details In-Document Search Title: The Equation of State of LLM-105 (2,6-diamino-3,5-dinitropyrazine-1-oxide) Authors: Zaug, J M ; Stavrou, E ; Kalkan, B Publication Date: 2015-02-25 OSTI Identifier: 1184137 Report Number(s): LLNL-PROC-667859 DOE Contract Number: DE-AC52-07NA27344 Resource Type: Conference Resource Relation: Conference: Presented at: The Equation of
Kordilla, Jannes; Pan, Wenxiao; Tartakovsky, Alexandre M.
2014-12-14
We propose a novel Smoothed Particle Hydrodynamics (SPH) discretization of the fully-coupled Landau-Lifshitz-Navier-Stokes (LLNS) and advection-diffusion equations. The accuracy of the SPH solution of the LLNS equations is demonstrated by comparing the scaling of velocity variance and self-diffusion coefficient with kinetic temperature and particle mass obtained from the SPH simulations and analytical solutions. The spatial covariance of pressure and velocity fluctuations are found to be in a good agreement with theoretical models. To validate the accuracy of the SPH method for the coupled LLNS and advection-diffusion equations, we simulate the interface between two miscible fluids. We study the formation of the so-called giant fluctuations of the front between light and heavy fluids with and without gravity, where the light fluid lays on the top of the heavy fluid. We find that the power spectra of the simulated concentration field is in good agreement with the experiments and analytical solutions. In the absence of gravity the the power spectra decays as the power -4 of the wave number except for small wave numbers which diverge from this power law behavior due to the effect of finite domain size. Gravity suppresses the fluctuations resulting in the much weaker dependence of the power spectra on the wave number. Finally the model is used to study the effect of thermal fluctuation on the Rayleigh-Taylor instability, an unstable dynamics of the front between a heavy fluid overlying a light fluid. The front dynamics is shown to agree well with the analytical solutions.
Field theory and weak Euler-Lagrange equation for classical particle-field systems
Qin, Hong; Burby, Joshua W; Davidson, Ronald C
2014-10-01
It is commonly believed that energy-momentum conservation is the result of space-time symmetry. However, for classical particle-field systems, e.g., Klimontovich-Maxwell and Klimontovich- Poisson systems, such a connection hasn't been formally established. The difficulty is due to the fact that particles and the electromagnetic fields reside on different manifolds. To establish the connection, the standard Euler-Lagrange equation needs to be generalized to a weak form. Using this technique, energy-momentum conservation laws that are difficult to find otherwise can be systematically derived.
Gligoric, Goran; Hadzievski, Ljupco; Maluckov, Aleksandra; Malomed, Boris A.
2009-05-15
The stability and collapse of fundamental unstaggered bright solitons in the discrete Schroedinger equation with the nonpolynomial on-site nonlinearity, which models a nearly one-dimensional Bose-Einstein condensate trapped in a deep optical lattice, are studied in the presence of the long-range dipole-dipole (DD) interactions. The cases of both attractive and repulsive contact and DD interaction are considered. The results are summarized in the form of stability-collapse diagrams in the parametric space of the model, which demonstrate that the attractive DD interactions stabilize the solitons and help to prevent the collapse. Mobility of the discrete solitons is briefly considered too.
Effects of bounded space in the solutions of time-space fractional diffusion equation
Allami, M. H. [Laser and Plasma Research Institute, Shahid Beheshti University, Tehran (Iran, Islamic Republic of); Shokri, B. [Laser and Plasma Research Institute, Shahid Beheshti University, Tehran (Iran, Islamic Republic of); Physics Department, Shahid Beheshti University, G.C., Tehran (Iran, Islamic Republic of)
2010-12-15
By using a recently proposed numerical method, the fractional diffusion equation with memory in a finite domain is solved for different asymmetry parameters and fractional orders. Some scaling laws are revisited in this condition, such as growth rate in a distance from pulse perturbation, the time when the perturbative peak reaches the other points, and advectionlike behavior as a result of asymmetry and memory. Conditions for negativity and instability of solutions are shown. Also up-hill transport and its time-space region are studied.
Biondini, Gino; Kova?i?, Gregor
2014-03-15
The inverse scattering transform for the focusing nonlinear Schrdinger equation with non-zero boundary conditions at infinity is presented, including the determination of the analyticity of the scattering eigenfunctions, the introduction of the appropriate Riemann surface and uniformization variable, the symmetries, discrete spectrum, asymptotics, trace formulae and the so-called theta condition, and the formulation of the inverse problem in terms of a Riemann-Hilbert problem. In addition, the general behavior of the soliton solutions is discussed, as well as the reductions to all special cases previously discussed in the literature.
(U) A Gruneisen Equation of State for TPX. Application in FLAG
Fredenburg, David A.; Aslam, Tariq Dennis; Bennett, Langdon Stanford
2015-11-02
A Gruneisen equation of state (EOS) is developed for the polymer TPX (poly 4-methyl-1-pentene) within the LANL hydrocode FLAG. Experimental shock Hugoniot data for TPX is fit to a form of the Gruneisen EOS, and the necessary parameters for implementing the TPX EOS in FLAG are presented. The TPX EOS is further validated through one-dimensional simulations of recent double-shock experiments, and a comparison is made between the new Gruneisen EOS for TPX and the EOS representation for TPX used in the LANL Common Model.
Optimal recovery of the solution of the heat equation from inaccurate data
Magaril-Il'yaev, G G; Osipenko, Konstantin Yu
2009-06-30
The problem of optimal recovery of the solution of the heat equation in the entire space at a fixed instant of time from inaccurate observations of this solution at some other instants of time is investigated. Explicit expressions for an optimal recovery method and its error are given. The solution of a similar problem with a priori information about the temperature distribution at some instants of time is also given. In all cases the optimal method uses information about at most two observations. Bibliography: 22 titles.
Stabilization of the solution of adoubly nonlinear parabolic equation
Andriyanova, R; Mukminov, F Kh
2013-09-30
The method of Galerkin approximations is employed to prove the existence of astrong global (in time) solution of adoubly nonlinear parabolic equation in an unbounded domain. The second integral identity is established for Galerkin approximations, and passing to the limit in it an estimate for the decay rate of the norm of the solution from below is obtained. The estimates characterizing the decay rate of the solution as x?? obtained here are used to derive an upper bound for the decay rate of the solution with respect to time; the resulting estimate is pretty close to the lower one. Bibliography: 17 titles.
Photon equation of motion with application to the electron's anomalous magnetic moment
Ritchie, A B
2007-12-06
The photon equation of motion previously applied to the Lamb shift is here applied to the anomalous magnetic moment of the electron. Exact agreement is obtained with the QED result of Schwinger. The photon theory treats the radiative correction to the photon in the presence of the electron rather than its inverse as in standard QED. The result is found to be first-order in the photon-electron interaction rather than second-order as in standard QED, introducing an ease of calculation hitherto unavailable.
Hamiltonian field description of the one-dimensional Poisson-Vlasov equations
Morrison, P.J.
1981-07-01
The one-dimensional Poisson-Vlasov equations are cast into Hamiltonian form. A Poisson Bracket in terms of the phase space density, as sole dynamical variable, is presented. This Poisson bracket is not of the usual form, but possesses the commutator properties of antisymmetry, bilinearity, and nonassociativity by virtue of the Jacobi requirement. Clebsch potentials are seen to yield a conventional (canonical) formulation. This formulation is discretized by expansion in terms of an arbitrary complete set of basis functions. In particular, a wave field representation is obtained.
Valilyev, O.V.; Paolucci, S.
1996-05-01
A dynamically adaptive multilevel structure of the algorithm provides a simple way to adapt computational refinements to local demands of the solution. High resolution computations are performed only in regions where sharp transitions occur. The scheme handles general boundary conditions. The method is applied to the solution of the one-dimensional Burgers equation with small viscosity, a moving shock problem, and a nonlinear thermoacoustic wave problem. The results indicate that the method is very accurate and efficient. 16 refs., 9 figs., 2 tab.
Validation of a zero-equation turbulence model for complex indoor airflow simulation
Srebric, J.; Chen, Q.; Glicksman, L.R.
1999-07-01
The design of an indoor environment requires a tool that can quickly predict the three-dimensional distributions of air velocity, temperature, and contaminant concentrations in the room on a desktop computer. This investigation has tested a zero-equation turbulence model for the prediction of the indoor environment in an office with displacement ventilation, with a heater and infiltration and with forced convection and a partition wall. The computed air velocity and temperature distributions agree well with the measured data. The computing time for each case is less than seven minutes on a PC Pentium II, 350 MHz.
Momentum space iterative solution of the time-dependent Schrödinger equation
Kiss, G. Zs.; Borbély, S.; Nagy, L.
2013-11-13
We present a novel approach, the iterative solution of the time-dependent Schrödinger equation (iTDSE model), for the investigation of atomic systems interacting with external laser fields. This model is the extension of the momentum-space strong-field approximation (MSSFA) [1], in which the Coulomb potential was considered only as a first order perturbation. In the iTDSE approach higher order terms were gradually introduced until convergence was achieved. Benchmark calculations were done on the hydrogen atom, and the obtained results were compared to the direct numerical solution [2].
Dissipation in a rotating frame: Master equation, effective temperature, and Lamb shift
Verso, Alvise; Ankerhold, Joachim
2010-02-15
Motivated by recent realizations of microwave-driven nonlinear resonators in superconducting circuits, the impact of environmental degrees of freedom is analyzed as seen from a rotating frame. A system plus reservoir model is applied to consistently derive in the weak coupling limit the master equation for the reduced density in the moving frame and near the first bifurcation threshold. The concept of an effective temperature is introduced to analyze to what extent a detailed balance relation exists. Explicit expressions are also found for the Lamb-shift. Results for ohmic baths are in agreement with experimental findings, while for structured environments population inversion is predicted that may qualitatively explain recent observations.
The role of electron equation of state in heating partition of protons in a collisionless plasma
Parashar, Tulasi N.; Vasquez, Bernard J.; Markovskii, Sergei A.
2014-02-15
One of the outstanding questions related to the solar wind is the heating of solar wind plasma. Addressing this question requires a self consistent treatment of the kinetic physics of a collisionless plasma. A hybrid code (with particle ions and fluid electrons) is one of the most convenient computational tools, which allows us to explore self consistent ion kinetics, while saving us computational time as compared to the full particle in cell codes. A common assumption used in hybrid codes is that of isothermal electrons. In this paper, we discuss the role that the equation of state for electrons could potentially play in determining the ion kinetics.
Equations of State of Anhydrous AlF3 and AlI3: Modeling of Extreme...
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Condition Halide Chemistry Citation Details In-Document Search Title: Equations of State of Anhydrous AlF3 and AlI3: Modeling of Extreme Condition Halide Chemistry Authors: ...
Stephani, H.
1988-07-01
The framework of Lie--Baecklund (or generalized) symmetries is used to give a unifying view of some of the known symmetries of Einstein's field equations for the vacuum or perfect fluid case (with a ..mu.. = p or a ..mu..+3p = 0 equation of state). These symmetries occur if space-time admits one or two Killing vectors (orthogonal or parallel, respectively, to the four-velocity in the perfect fluid case).
Zakharov-Kuznetsov equation in a magnetized plasma with two temperature superthermal electrons
Saini, N. S. Chahal, B. S.; Bains, A. S.; Bedi, C.
2014-02-15
A nonlinear Zakharov-Kuznetsov (ZK) equation for ion-acoustic solitary waves (IASWs) in a magnetized plasmas containing kappa distributed cold and hot electrons is derived by using reductive perturbation method. From the solution of ZK equation, the characteristics of IASWs have been studied under the influence of various plasma parameters. Existence domain of physical parameters is determined. It has been observed that the present plasma system supports the existence of both positive as well as negative potential solitons. The combined effects of cold to hot electron temperature ratio (?), density ratio of cold electrons to ions (f), superthermality of cold and hot electrons (?{sub c},?{sub h}), strength of magnetic field (via ?{sub i}), and obliqueness (?) significantly influence the profile of IASWs. The physical parameters play a great role to modify the width and amplitude of the solitary structures. The stability analysis is also presented in this investigation and parametric range is determined to check the presence of stable and unstable solitons. The findings of this study are important to the physics of electrostatic wave structures in the Saturn's magnetosphere where two temperature electrons with kappa distribution exist.
Wong, Pring; Pang, Li-Hui; Huang, Long-Gang; Li, Yan-Qing; Lei, Ming; Liu, Wen-Jun
2015-09-15
The study of the complex Ginzburg–Landau equation, which can describe the fiber laser system, is of significance for ultra-fast laser. In this paper, dromion-like structures for the complex Ginzburg–Landau equation are considered due to their abundant nonlinear dynamics. Via the modified Hirota method and simplified assumption, the analytic dromion-like solution is obtained. The partial asymmetry of structure is particularly discussed, which arises from asymmetry of nonlinear and dispersion terms. Furthermore, the stability of dromion-like structures is analyzed. Oscillation structure emerges to exhibit strong interference when the dispersion loss is perturbed. Through the appropriate modulation of modified exponent parameter, the oscillation structure is transformed into two dromion-like structures. It indicates that the dromion-like structure is unstable, and the coherence intensity is affected by the modified exponent parameter. Results in this paper may be useful in accounting for some nonlinear phenomena in fiber laser systems, and understanding the essential role of modified Hirota method.
Time-local view of nonequilibrium statistical mechanics. II. Generalized Langevin equations
Der, R.
1987-01-01
On a semiphenomenological level, generalized Langevin equations are usually obtained by adding a random force (RF) term to macroscopic deterministic equations assumed to be known. Here this procedure is made rigorous by conveniently redefining the RF, which is shown to be colored noise weakly correlated with the observables at earlier times due to the finite lifetime of microscopic events. Corresponding fluctuation-dissipation theorems are derived. Explicit expressions for the spectral density of the fluctuations are obtained in a particularly simple form, with the deviation of the line shape from the Lorentzian being related most explicitly to the spectral density of the RF. Well-known low-frequency expressions and the Einstein relation of (generalized) Brownian motion theory are modified so as to include lifetime effects. New sum rules are obtained relating dissipative quantities to contour integrals (in the complex frequency domain) over spectral densities or corresponding response functions. The Heisenberg dynamics of a complete set of macroobservables is shown to be equivalent to a generalized Orstein-Uhlenbeck stochastic process which is a non-Markovian process due to the lifetime effects.
Roberts, Nathan V.; Demkowiz, Leszek; Moser, Robert
2015-11-15
The discontinuous Petrov-Galerkin methodology with optimal test functions (DPG) of Demkowicz and Gopalakrishnan [18, 20] guarantees the optimality of the solution in an energy norm, and provides several features facilitating adaptive schemes. Whereas Bubnov-Galerkin methods use identical trial and test spaces, Petrov-Galerkin methods allow these function spaces to differ. In DPG, test functions are computed on the fly and are chosen to realize the supremum in the inf-sup condition; the method is equivalent to a minimum residual method. For well-posed problems with sufficiently regular solutions, DPG can be shown to converge at optimal rates—the inf-sup constants governing the convergence are mesh-independent, and of the same order as those governing the continuous problem [48]. DPG also provides an accurate mechanism for measuring the error, and this can be used to drive adaptive mesh refinements. We employ DPG to solve the steady incompressible Navier-Stokes equations in two dimensions, building on previous work on the Stokes equations, and focusing particularly on the usefulness of the approach for automatic adaptivity starting from a coarse mesh. We apply our approach to a manufactured solution due to Kovasznay as well as the lid-driven cavity flow, backward-facing step, and flow past a cylinder problems.
Chilton, Sven H.
2008-04-15
The WARP code is a robust electrostatic particle-in-cell simulation package used to model charged particle beams with strong space-charge forces. A fundamental operation associated with seeding detailed simulations of a beam transport channel is to generate initial conditions where the beam distribution is matched to the structure of a periodic focusing lattice. This is done by solving for periodic, matched solutions to a coupled set of ODEs called the Kapchinskij-Vladimirskij (KV) envelope equations, which describe the evolution of low-order beam moments subject to applied lattice focusing, space-charge defocusing, and thermal defocusing forces. Recently, an iterative numerical method was developed (Lund, Chilton, and Lee, Efficient computation of matched solutions to the KV envelope equations for periodic focusing lattices, Physical Review Special Topics-Accelerators and Beams 9, 064201 2006) to generate matching conditions in a highly flexible, convergent, and fail-safe manner. This method is extended and implemented in the WARP code as a Python package to vastly ease the setup of detailed simulations. In particular, the Python package accommodates any linear applied lattice focusing functions without skew coupling, and a more general set of beam parameter specifications than its predecessor. Lattice strength iteration tools were added to facilitate the implementation of problems with specific applied focusing strengths.
Chilton, Sven; Chilton, Sven H.
2008-07-01
The WARP code is a robust electrostatic particle-in-cell simulation package used to model charged particle beams with strong space-charge forces. A fundamental operation associated with seeding detailed simulations of a beam transport channel is to generate initial conditions where the beam distribution is matched to the structure of a periodic focusing lattice. This is done by solving for periodic, matched solutions to a coupled set of ODEs called the Kapchinskij-Vladimirskij (KV) envelope equations, which describe the evolution of low-order beam moments subject to applied lattice focusing, space-charge defocusing, and thermal defocusing forces. Recently, an iterative numerical method was developed (Lund, Chilton, and Lee, Efficient computation of matched solutions to the KV envelope equations for periodic focusing lattices, Physical Review Special Topics-Accelerators and Beams 9, 064201 2006) to generate matching conditions in a highly flexible, convergent, and fail-safe manner. This method is extended and implemented in the WARP code as a Python package to vastly ease the setup of detailed simulations. In particular, the Python package accommodates any linear applied lattice focusing functions without skew coupling, and a more general set of beam parameter specifications than its predecessor. Lattice strength iteration tools were added to facilitate the implementation of problems with specific applied focusing strengths.
Measurements of the equations of state and spectrum of nonideal xenon plasma under shock compression
Zheng, J.; Gu, Y. J.; Chen, Z. Y.; Chen, Q. F.
2010-08-15
Experimental equations of state on generation of nonideal xenon plasma by intense shock wave compression was presented in the ranges of pressure of 2-16 GPa and temperature of 31-50 kK, and the xenon plasma with the nonideal coupling parameter {Gamma} range from 0.6-2.1 was generated. The shock wave was produced using the flyer plate impact and accelerated up to {approx}6 km/s with a two-stage light gas gun. Gaseous specimens were shocked from two initial pressures of 0.80 and 4.72 MPa at room temperature. Time-resolved spectral radiation histories were recorded by using a multiwavelength channel pyrometer. The transient spectra with the wavelength range of 460-700 nm were recorded by using a spectrometer to evaluate the shock temperature. Shock velocity was measured and particle velocity was determined by the impedance matching methods. The equations of state of xenon plasma and ionization degree have been discussed in terms of the self-consistent fluid variational theory.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Hu, S. X.; Collins, L. A.; Goncharov, V. N.; Kress, J. D.; McCrory, R. L.; Skupsky, S.
2015-10-14
Obtaining an accurate equation of state (EOS) of polystyrene (CH) is crucial to reliably design inertial confinement fusion (ICF) capsules using CH/CH-based ablators. Thus, with first-principles calculations, we have investigated the extended EOS of CH over a wide range of plasma conditions (ρ = 0.1 to 100 g/cm3 and T = 1,000 to 4,000,000 K). When compared with the widely used SESAME-EOS table, the first-principles equation of state (FPEOS) of CH has shown significant differences in the low-temperature regime, in which strong coupling and electron degeneracy play an essential role in determining plasma properties. Hydrodynamic simulations of cryogenic target implosionsmore » on OMEGA using the FPEOS table of CH have predicted ~5% reduction in implosion velocity and ~30% decrease in neutron yield in comparison with the usual SESAME simulations. This is attributed to the ~10% lower mass ablation rate of CH predicted by FPEOS. Simulations using CH-FPEOS show better agreement with measurements of Hugoniot temperature and scattered lights from ICF implosions.« less
Hu, S. X.; Collins, L. A.; Goncharov, V. N.; Kress, J. D.; McCrory, R. L.; Skupsky, S.
2015-10-14
Obtaining an accurate equation of state (EOS) of polystyrene (CH) is crucial to reliably design inertial confinement fusion (ICF) capsules using CH/CH-based ablators. Thus, with first-principles calculations, we have investigated the extended EOS of CH over a wide range of plasma conditions (ρ = 0.1 to 100 g/cm^{3} and T = 1,000 to 4,000,000 K). When compared with the widely used SESAME-EOS table, the first-principles equation of state (FPEOS) of CH has shown significant differences in the low-temperature regime, in which strong coupling and electron degeneracy play an essential role in determining plasma properties. Hydrodynamic simulations of cryogenic target implosions on OMEGA using the FPEOS table of CH have predicted ~5% reduction in implosion velocity and ~30% decrease in neutron yield in comparison with the usual SESAME simulations. This is attributed to the ~10% lower mass ablation rate of CH predicted by FPEOS. Simulations using CH-FPEOS show better agreement with measurements of Hugoniot temperature and scattered lights from ICF implosions.
Equation-based languages – A new paradigm for building energy modeling, simulation and optimization
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Wetter, Michael; Bonvini, Marco; Nouidui, Thierry S.
2016-04-01
Most of the state-of-the-art building simulation programs implement models in imperative programming languages. This complicates modeling and excludes the use of certain efficient methods for simulation and optimization. In contrast, equation-based modeling languages declare relations among variables, thereby allowing the use of computer algebra to enable much simpler schematic modeling and to generate efficient code for simulation and optimization. We contrast the two approaches in this paper. We explain how such manipulations support new use cases. In the first of two examples, we couple models of the electrical grid, multiple buildings, HVAC systems and controllers to test a controller thatmore » adjusts building room temperatures and PV inverter reactive power to maintain power quality. In the second example, we contrast the computing time for solving an optimal control problem for a room-level model predictive controller with and without symbolic manipulations. As a result, exploiting the equation-based language led to 2, 200 times faster solution« less
Xiaodong Liu; Lijun Xuan; Hong Luo; Yidong Xia
2001-01-01
A reconstructed discontinuous Galerkin (rDG(P1P2)) method, originally introduced for the compressible Euler equations, is developed for the solution of the compressible Navier- Stokes equations on 3D hybrid grids. In this method, a piecewise quadratic polynomial solution is obtained from the underlying piecewise linear DG solution using a hierarchical Weighted Essentially Non-Oscillatory (WENO) reconstruction. The reconstructed quadratic polynomial solution is then used for the computation of the inviscid fluxes and the viscous fluxes using the second formulation of Bassi and Reay (Bassi-Rebay II). The developed rDG(P1P2) method is used to compute a variety of flow problems to assess its accuracy, efficiency, and robustness. The numerical results demonstrate that the rDG(P1P2) method is able to achieve the designed third-order of accuracy at a cost slightly higher than its underlying second-order DG method, outperform the third order DG method in terms of both computing costs and storage requirements, and obtain reliable and accurate solutions to the large eddy simulation (LES) and direct numerical simulation (DNS) of compressible turbulent flows.
Huang, Lianjie; Simonetti, Francesco; Huthwaite, Peter; Rosenberg, Robert; Williamson, Michael
2010-01-01
Ultrasound image resolution and quality need to be significantly improved for breast microcalcification detection. Super-resolution imaging with the factorization method has recently been developed as a promising tool to break through the resolution limit of conventional imaging. In addition, wave-equation reflection imaging has become an effective method to reduce image speckles by properly handling ultrasound scattering/diffraction from breast heterogeneities during image reconstruction. We explore the capabilities of a novel super-resolution ultrasound imaging method and a wave-equation reflection imaging scheme for detecting breast microcalcifications. Super-resolution imaging uses the singular value decomposition and a factorization scheme to achieve an image resolution that is not possible for conventional ultrasound imaging. Wave-equation reflection imaging employs a solution to the acoustic-wave equation in heterogeneous media to backpropagate ultrasound scattering/diffraction waves to scatters and form images of heterogeneities. We construct numerical breast phantoms using in vivo breast images, and use a finite-difference wave-equation scheme to generate ultrasound data scattered from inclusions that mimic microcalcifications. We demonstrate that microcalcifications can be detected at full spatial resolution using the super-resolution ultrasound imaging and wave-equation reflection imaging methods.
Likhacheva, Anna Y.; Rashchenko, Sergey V.; Chanyshev, Artem D.; Litasov, Konstantin D.; Department of Geology and Geophysics, Novosibirsk State University, Novosibirsk 630090 ; Inerbaev, Talgat M.; Kilin, Dmitry S.
2014-04-28
In a wide range of P-T conditions, such fundamental characteristics as compressibility and thermoelastic properties remain unknown for most classes of organic compounds. Here we attempt to clarify this issue by the example of naphthalene as a model representative of polycyclic aromatic hydrocarbons (PAHs). The elastic behavior of solid naphthalene was studied by in situ synchrotron powder X-ray diffraction up to 13 GPa and 773 K and first principles computations to 20 GPa and 773 K. Fitting of the P-V experimental data to Vinet equation of state yielded T 0 = 8.4(3) GPa and T' = 7.2 (3) at V0 = 361 (3), whereas the thermal expansion coefficient was found to be extremely low at P > 3 GPa (about 10(-5) K(-1)), in agreement with theoretical estimation. Such a diminishing of thermal effects with the pressure increase clearly demonstrates a specific feature of the high-pressure behavior of molecular crystals like PAHs, associated with a low energy of intermolecular interactions.
Analysis of the Sultana-Dyer cosmological black hole solution of the Einstein equations
Faraoni, Valerio
2009-08-15
The Sultana-Dyer solution of general relativity representing a black hole embedded in a special cosmological background is analyzed. We find an expanding (weak) spacetime singularity instead of the reported conformal Killing horizon, which is covered by an expanding black hole apparent horizon (internal to a cosmological apparent horizon) for most of the history of the Universe. This singularity was naked early on. The global structure of the solution is studied as well.
Algorithmically scalable block preconditioner for fully implicit shallow water equations in CAM-SE
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Lott, P Aaron; Woodward, Carol; Evans, Katherine J
2015-01-01
Performing accurate and efficient numerical simulation of global atmospheric climate models is challenging due to the disparate length and time scales over which physical processes interact. Implicit solvers enable the physical system to be integrated with a time step commensurate with processes being studied. The dominant cost of an implicit time step is the ancillary linear system solves, so we have developed a preconditioner aimed at improving the efficiency of these linear system solves. Our preconditioner is based on an approximate block factorization of the linearized shallow-water equations and has been implemented within the spectral element dynamical core within themore » Community Atmospheric Model (CAM-SE). In this paper we discuss the development and scalability of the preconditioner for a suite of test cases with the implicit shallow-water solver within CAM-SE.« less
Equation-of-State Test Suite for the DYNA3D Code
Benjamin, Russell D.
2015-11-05
This document describes the creation and implementation of a test suite for the Equationof- State models in the DYNA3D code. A customized input deck has been created for each model, as well as a script that extracts the relevant data from the high-speed edit file created by DYNA3D. Each equation-of-state model is broken apart and individual elements of the model are tested, as well as testing the entire model. The input deck for each model is described and the results of the tests are discussed. The intent of this work is to add this test suite to the validation suite presently used for DYNA3D.
Accelerating Time Integration for the Shallow Water Equations on the Sphere Using GPUs
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Archibald, R.; Evans, K. J.; Salinger, A.
2015-06-01
The push towards larger and larger computational platforms has made it possible for climate simulations to resolve climate dynamics across multiple spatial and temporal scales. This direction in climate simulation has created a strong need to develop scalable time-stepping methods capable of accelerating throughput on high performance computing. This work details the recent advances in the implementation of implicit time stepping on a spectral element cube-sphere grid using graphical processing units (GPU) based machines. We demonstrate how solvers in the Trilinos project are interfaced with ACME and GPU kernels can significantly increase computational speed of the residual calculations in themore » implicit time stepping method for the shallow water equations on the sphere. We show the optimization gains and data structure reorganization that facilitates the performance improvements.« less
Collapse for the higher-order nonlinear Schrödinger equation
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Achilleos, V.; Diamantidis, S.; Frantzeskakis, D. J.; Horikis, T. P.; Karachalios, N. I.; Kevrekidis, P. G.
2016-02-01
We examine conditions for finite-time collapse of the solutions of the higher-order nonlinear Schrodinger (NLS) equation incorporating third-order dispersion, self-steepening, linear and nonlinear gain and loss, and Raman scattering; this is a system that appears in many physical contexts as a more realistic generalization of the integrable NLS. By using energy arguments, it is found that the collapse dynamics is chiefly controlled by the linear/nonlinear gain/loss strengths. We identify a critical value of the linear gain, separating the possible decay of solutions to the trivial zero-state, from collapse. The numerical simulations, performed for a wide class of initial data, aremore » found to be in very good agreement with the analytical results, and reveal long-time stability properties of localized solutions. The role of the higher-order effects to the transient dynamics is also revealed in these simulations.« less
Relativistic equation of state at subnuclear densities in the Thomas-Fermi approximation
Zhang, Z. W.; Shen, H., E-mail: shennankai@gmail.com [School of Physics, Nankai University, Tianjin 300071 (China)
2014-06-20
We study the non-uniform nuclear matter using the self-consistent Thomas-Fermi approximation with a relativistic mean-field model. The non-uniform matter is assumed to be composed of a lattice of heavy nuclei surrounded by dripped nucleons. At each temperature T, proton fraction Y{sub p} , and baryon mass density ? {sub B}, we determine the thermodynamically favored state by minimizing the free energy with respect to the radius of the Wigner-Seitz cell, while the nucleon distribution in the cell can be determined self-consistently in the Thomas-Fermi approximation. A detailed comparison is made between the present results and previous calculations in the Thomas-Fermi approximation with a parameterized nucleon distribution that has been adopted in the widely used Shen equation of state.
A node-centered local refinement algorithm for poisson's equation in complex geometries
McCorquodale, Peter; Colella, Phillip; Grote, David P.; Vay, Jean-Luc
2004-05-04
This paper presents a method for solving Poisson's equation with Dirichlet boundary conditions on an irregular bounded three-dimensional region. The method uses a nodal-point discretization and adaptive mesh refinement (AMR) on Cartesian grids, and the AMR multigrid solver of Almgren. The discrete Laplacian operator at internal boundaries comes from either linear or quadratic (Shortley-Weller) extrapolation, and the two methods are compared. It is shown that either way, solution error is second order in the mesh spacing. Error in the gradient of the solution is first order with linear extrapolation, but second order with Shortley-Weller. Examples are given with comparison with the exact solution. The method is also applied to a heavy-ion fusion accelerator problem, showing the advantage of adaptivity.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Zhang, Yang; Chong, Edwin K. P.; Hannig, Jan; Estep, Donald
2013-01-01
We inmore » troduce a continuum modeling method to approximate a class of large wireless networks by nonlinear partial differential equations (PDEs). This method is based on the convergence of a sequence of underlying Markov chains of the network indexed by N , the number of nodes in the network. As N goes to infinity, the sequence converges to a continuum limit, which is the solution of a certain nonlinear PDE. We first describe PDE models for networks with uniformly located nodes and then generalize to networks with nonuniformly located, and possibly mobile, nodes. Based on the PDE models, we develop a method to control the transmissions in nonuniform networks so that the continuum limit is invariant under perturbations in node locations. This enables the networks to maintain stable global characteristics in the presence of varying node locations.« less
Predictions of the equation of state of cerium yield interesting insights into experimental results
Cherne, Frank J; Jensen, Brian J; Rigg, Paulo A; Elkin, Vyacheslav M
2009-01-01
There has been much interest in the past in understanding the dynamic properties of phase changing materials. In this paper we begin to explore the dynamic properties of the complex material of cerium. Cerium metal is a good candidate material to explore capabilities in determining a dynamic phase diagram on account of its low dynamic phase boundaries, namely, the {gamma}-{alpha}, and {alpha}-liquid phase boundaries. Here we present a combination of experimental results with calculated results to try to understand the dynamic behavior of the material. Using the front surface impact technique, we performed a series of experiments which displayed a rarefaction shock upon release. These experiments show that the reversion shock stresses occur at different magnitudes, allowing us to plot out the {gamma}-{alpha} phase boundary. Applying a multiphase equation of state a broader understanding of the experimental results will be discussed.
The fixed hypernode method for the solution of the many body Schroedinger equation
Pederiva, F; Kalos, M H; Reboredo, F; Bressanini, D; Guclu, D; Colletti, L; Umrigar, C J
2006-01-24
We propose a new scheme for an approximate solution of the Schroedinger equation for a many-body interacting system, based on the use of pairs of walkers. Trial wavefunctions for these pairs are combinations of standard symmetric and antisymmetric wavefunctions. The method consists in applying a fixed-node restriction in the enlarged space, and computing the energy of the antisymmetric state from the knowledge of the exact ground state energy for the symmetric state. We made two conjectures: first, that this fixed-hypernode energy is an upper bound to the true fermion energy; second that this bound would necessarily be lower than the usual fixed-node energy using the same antisymmetric trial function. The first conjecture is true, and is proved in this paper. The second is not, and numerical and analytical counterexamples are given. The question of whether the fixed-hypernode energy can be better than the usual bound remains open.
Leung Shingyu; Qian Jianliang
2010-11-20
We propose the backward phase flow method to implement the Fourier-Bros-Iagolnitzer (FBI)-transform-based Eulerian Gaussian beam method for solving the Schroedinger equation in the semi-classical regime. The idea of Eulerian Gaussian beams has been first proposed in . In this paper we aim at two crucial computational issues of the Eulerian Gaussian beam method: how to carry out long-time beam propagation and how to compute beam ingredients rapidly in phase space. By virtue of the FBI transform, we address the first issue by introducing the reinitialization strategy into the Eulerian Gaussian beam framework. Essentially we reinitialize beam propagation by applying the FBI transform to wavefields at intermediate time steps when the beams become too wide. To address the second issue, inspired by the original phase flow method, we propose the backward phase flow method which allows us to compute beam ingredients rapidly. Numerical examples demonstrate the efficiency and accuracy of the proposed algorithms.
Accelerated molecular dynamics and equation-free methods for simulating diffusion in solids.
Deng, Jie; Zimmerman, Jonathan A.; Thompson, Aidan Patrick; Brown, William Michael; Plimpton, Steven James; Zhou, Xiao Wang; Wagner, Gregory John; Erickson, Lindsay Crowl
2011-09-01
Many of the most important and hardest-to-solve problems related to the synthesis, performance, and aging of materials involve diffusion through the material or along surfaces and interfaces. These diffusion processes are driven by motions at the atomic scale, but traditional atomistic simulation methods such as molecular dynamics are limited to very short timescales on the order of the atomic vibration period (less than a picosecond), while macroscale diffusion takes place over timescales many orders of magnitude larger. We have completed an LDRD project with the goal of developing and implementing new simulation tools to overcome this timescale problem. In particular, we have focused on two main classes of methods: accelerated molecular dynamics methods that seek to extend the timescale attainable in atomistic simulations, and so-called 'equation-free' methods that combine a fine scale atomistic description of a system with a slower, coarse scale description in order to project the system forward over long times.
Wave chaos in the stadium: Statistical properties of short-wave solutions of the Helmholtz equation
McDonald, S.W.; Kaufman, A.N.
1988-04-15
We numerically investigate statistical properties of short-wavelength normal modes and the spectrum for the Helmholtz equation in a two-dimensional stadium-shaped region. As the geometrical optics rays within this boundary (billiards) are nonintegrable, this wave problem serves as a simple model for the study of quantum chaos. The local spatial correlation function
Shafii, Mohammad Ali Meidianti, Rahma Wildian, Fitriyani, Dian; Tongkukut, Seni H. J.; Arkundato, Artoto
2014-09-30
Theoretical analysis of integral neutron transport equation using collision probability (CP) method with quadratic flux approach has been carried out. In general, the solution of the neutron transport using the CP method is performed with the flat flux approach. In this research, the CP method is implemented in the cylindrical nuclear fuel cell with the spatial of mesh being conducted into non flat flux approach. It means that the neutron flux at any point in the nuclear fuel cell are considered different each other followed the distribution pattern of quadratic flux. The result is presented here in the form of quadratic flux that is better understanding of the real condition in the cell calculation and as a starting point to be applied in computational calculation.
A Singular Differential Equation Stemming from an Optimal Control Problem in Financial Economics
Brunovsky, Pavol; Cerny, Ales; Winkler, Michael
2013-10-15
We consider the ordinary differential equation x{sup 2} u'' = axu'+bu-c(u'-1){sup 2}, x Element-Of (0,x{sub 0}), with a Element-Of R, b Element-Of R , c>0 and the singular initial condition u(0)=0, which in financial economics describes optimal disposal of an asset in a market with liquidity effects. It is shown in the paper that if a+b<0 then no continuous solutions exist, whereas if a+b>0 then there are infinitely many continuous solutions with indistinguishable asymptotics near 0. Moreover, it is proved that in the latter case there is precisely one solution u corresponding to the choice x{sub 0}={infinity} which is such that 0{<=}u(x){<=}x for all x>0, and that this solution is strictly increasing and concave.
Analytical solutions of a fractional diffusion-advection equation for solar cosmic-ray transport
Litvinenko, Yuri E.; Effenberger, Frederic
2014-12-01
Motivated by recent applications of superdiffusive transport models to shock-accelerated particle distributions in the heliosphere, we analytically solve a one-dimensional fractional diffusion-advection equation for the particle density. We derive an exact Fourier transform solution, simplify it in a weak diffusion approximation, and compare the new solution with previously available analytical results and with a semi-numerical solution based on a Fourier series expansion. We apply the results to the problem of describing the transport of energetic particles, accelerated at a traveling heliospheric shock. Our analysis shows that significant errors may result from assuming an infinite initial distance between the shock and the observer. We argue that the shock travel time should be a parameter of a realistic superdiffusive transport model.
Kowalski, Karol
2006-09-28
The stationary conditions obtained from approximate coupled-cluster functional derived from the Numerator-Denominator connected Expansion (NDC) [K. Kowalski, P. Piecuch, J Chem. Phys. 122 (2005) 074107] are employed to calculate the linear response of cluster amplitudes. A simple scheme that involves singly and doubly excited amplitudes, termed locally renormalized equation-of-motion approach with singles and doubles (LR-EOMCCSD), is compared with other excited-state methods that include up to two-body operators in the wavefunction expansion. In particular, the impact of the local denominators on the excitation energies is discussed in detail. Several benchmark calculations on the CH+, C?, N?, O?, CIOCI molecules are presented to illustrate the performance of the LR-EOMCCSD approach.
Jiang Haiyan; Cai Wei; Tsu, Raphael
2011-03-01
In this paper, the accuracy of the Frensley inflow boundary condition of the Wigner equation is analyzed in computing the I-V characteristics of a resonant tunneling diode (RTD). It is found that the Frensley inflow boundary condition for incoming electrons holds only exactly infinite away from the active device region and its accuracy depends on the length of contacts included in the simulation. For this study, the non-equilibrium Green's function (NEGF) with a Dirichlet to Neumann mapping boundary condition is used for comparison. The I-V characteristics of the RTD are found to agree between self-consistent NEGF and Wigner methods at low bias potentials with sufficiently large GaAs contact lengths. Finally, the relation between the negative differential conductance (NDC) of the RTD and the sizes of contact and buffer in the RTD is investigated using both methods.
Locally Renormalized Coupled-Cluster Equations for Singly and Doubly Excited Clusters
Kowalski, Karol
2006-07-10
The Numerator-Denominator Connected (NDC) Expansion for the Coupled-Cluster (CC) method [K. Kowalski, P. Piecuch, J. Chem. Phys. 122 (2005) 074107], is used to construct a new set of stationary conditions for approximate coupled-cluster approaches. Several CC approximations based on models involving singles and doubles (CCSD) as well as singles, doubles, and triples (CCSDT) are developed and discussed in the context of ground-state applications. The resulting locally-renormalized CCSD (LR-CCSD) and CCSDT (LR-CCSDT) equations are shown to regularize the expressions for the cluster amplitudes in the challenging situations that occur when the orbital energy differences approach zero. Affordable schemes for handling the local denominators (all-holes-Jn coupling), that naturally appear in locally renormalized formalisms, are also discussed.
Isothermal Multiphase Flash Calculations with the PC-SAFT Equation of State
Justo-Garcia, Daimler N.; Garcia-Sanchez, Fernando; Romero-Martinez, Ascencion
2008-03-05
A computational approach for isothermal multiphase flash calculations with the PC-SAFT (Perturbed-Chain Statistical Associating Fluid Theory) equation of state is presented. In the framework of the study of fluid phase equilibria of multicomponent systems, the general multiphase problem is the single most important calculation which consists of finding the correct number and types of phases and their corresponding equilibrium compositions such that the Gibbs energy of the system is a minimum. For solving this problem, the system Gibbs energy was minimized using a rigorous method for thermodynamic stability analysis to find the most stable state of the system. The efficiency and reliability of the approach to predict and calculate complex phase equilibria are illustrated by solving three typical problems encountered in the petroleum industry.
Di Nunno, Giulia; Khedher, Asma; Vanmaele, Michèle
2015-12-15
We consider a backward stochastic differential equation with jumps (BSDEJ) which is driven by a Brownian motion and a Poisson random measure. We present two candidate-approximations to this BSDEJ and we prove that the solution of each candidate-approximation converges to the solution of the original BSDEJ in a space which we specify. We use this result to investigate in further detail the consequences of the choice of the model to (partial) hedging in incomplete markets in finance. As an application, we consider models in which the small variations in the price dynamics are modeled with a Poisson random measure with infinite activity and models in which these small variations are modeled with a Brownian motion or are cut off. Using the convergence results on BSDEJs, we show that quadratic hedging strategies are robust towards the approximation of the market prices and we derive an estimation of the model risk.
Prediction of explosive cylinder tests using equations of state from the PANDA code
Kerley, G.I.; Christian-Frear, T.L.
1993-09-28
The PANDA code is used to construct tabular equations of state (EOS) for the detonation products of 24 explosives having CHNO compositions. These EOS, together with a reactive burn model, are used in numerical hydrocode calculations of cylinder tests. The predicted detonation properties and cylinder wall velocities are found to give very good agreement with experimental data. Calculations of flat plate acceleration tests for the HMX-based explosive LX14 are also made and shown to agree well with the measurements. The effects of the reaction zone on both the cylinder and flat plate tests are discussed. For TATB-based explosives, the differences between experiment and theory are consistently larger than for other compositions and may be due to nonideal (finite dimameter) behavior.
Accelerating Time Integration for the Shallow Water Equations on the Sphere Using GPUs
Archibald, R.; Evans, K. J.; Salinger, A.
2015-06-01
The push towards larger and larger computational platforms has made it possible for climate simulations to resolve climate dynamics across multiple spatial and temporal scales. This direction in climate simulation has created a strong need to develop scalable time-stepping methods capable of accelerating throughput on high performance computing. This work details the recent advances in the implementation of implicit time stepping on a spectral element cube-sphere grid using graphical processing units (GPU) based machines. We demonstrate how solvers in the Trilinos project are interfaced with ACME and GPU kernels can significantly increase computational speed of the residual calculations in the implicit time stepping method for the shallow water equations on the sphere. We show the optimization gains and data structure reorganization that facilitates the performance improvements.
Three-dimensional nonlinear Schroedinger equation in electron-positron-ion magnetoplasmas
Sabry, R.; Moslem, W. M.; El-Shamy, E. F.; Shukla, P. K.
2011-03-15
Three-dimensional ion-acoustic envelope soliton excitations in electron-positron-ion magnetoplasmas are interpreted. This is accomplished through the derivation of three-dimensional nonlinear Schroedinger equation, where the nonlinearity is balancing with the dispersive terms. The latter contains both an external magnetic field besides the usual plasma parameter effects. Based on the balance between the nonlinearity and the dispersion terms, the regions for possible envelope solitons are investigated indicating that new regimes for modulational instability of envelope ion-acoustic waves could be obtained, which cannot exist in the unmagnetized case. This will allow us to establish additional new regimes, different from the usual unmagnetized plasma, for envelope ion-acoustic waves to propagate in multicomponent plasma that may be observed in space or astrophysics.
Higher-order time integration of Coulomb collisions in a plasma using Langevin equations
Dimits, A.M.; Cohen, B.I.; Caflisch, R.E.; Rosin, M.S.; Ricketson, L.F.
2013-06-01
The extension of Langevin-equation Monte-Carlo algorithms for Coulomb collisions from the conventional EulerMaruyama time integration to the next higher order of accuracy, the Milstein scheme, has been developed, implemented, and tested. This extension proceeds via a formulation of the angular scattering directly as stochastic differential equations in the fixed-frame spherical-coordinate velocity variables. Results from the numerical implementation show the expected improvement [O(?t) vs. O(?t{sup 1/2})] in the strong convergence rate both for the speed |v| and angular components of the scattering. An important result is that this improved convergence is achieved for the angular component of the scattering if and only if the area-integral terms in the Milstein scheme are included. The resulting Milstein scheme is of value as a step towards algorithms with both improved accuracy and efficiency. These include both algorithms with improved convergence in the averages (weak convergence) and multi-time-level schemes. The latter have been shown to give a greatly reduced cost for a given overall error level when compared with conventional Monte-Carlo schemes, and their performance is improved considerably when the Milstein algorithm is used for the underlying time advance versus the EulerMaruyama algorithm. A new method for sampling the area integrals is given which is a simplification of an earlier direct method and which retains high accuracy. This method, while being useful in its own right because of its relative simplicity, is also expected to considerably reduce the computational requirements for the direct conditional sampling of the area integrals that is needed for adaptive strong integration.
(U) Equation of State and Compaction Modeling for CeO_{2}
Fredenburg, David A.; Chisolm, Eric D.
2014-10-20
Recent efforts have focused on developing a solid-liquid and three-phase equation of state (EOS) for CeO_{2}, while parallel experimental efforts have focused on obtaining high-fidelity Hugoniot measurements on CeO_{2} in the porous state. The current work examines the robustness of two CeO_{2} SESAME equations of state, a solid-liquid EOS, 96170, and a three-phase EOS, 96171, by validating the EOS against a suite of high-pressure shock compression experiments on initially porous CeO_{2}. At lower pressures compaction is considered by incorporating a two-term exponential form of the P-compaction model, using three separate definitions for ?(P). Simulations are executed spanning the partially compacted and fully compacted EOS regimes over the pressure range 0.5 - 109 GPa. Comparison of calculated Hugoniot results with those obtained experimentally indicate good agreement for all definitions of ?(P) with both the solid-liquid and three-phase EOS in the low-pressure compaction regime. At higher pressures the three-phase EOS does a better job at predicting the measured Hugoniot response, though at the highest pressures EOS 96171 predicts a less compliant response than is observed experimentally. Measured material velocity profiles of the shock-wave after it has transmitted through the powder are also compared with those simulated using with solid-liquid and three-phase EOS. Profiles lend insight into limits of the current experimental design, as well as the threshold conditions for the shock-induced phase transition in CeO_{2}.
A Bloch-Torrey Equation for Diffusion in a Deforming Media
Rohmer, Damien; Gullberg, Grant T.
2006-12-29
Diffusion Tensor Magnetic Resonance Imaging (DTMRI)technique enables the measurement of diffusion parameters and therefore,informs on the structure of the biological tissue. This technique isapplied with success to the static organs such as brain. However, thediffusion measurement on the dynamically deformable organs such as thein-vivo heart is a complex problem that has however a great potential inthe measurement of cardiac health. In order to understand the behavior ofthe Magnetic Resonance (MR)signal in a deforming media, the Bloch-Torreyequation that leads the MR behavior is expressed in general curvilinearcoordinates. These coordinates enable to follow the heart geometry anddeformations through time. The equation is finally discretized andpresented in a numerical formulation using implicit methods, in order toget a stable scheme that can be applied to any smooth deformations.Diffusion process enables the link between the macroscopic behavior ofmolecules and themicroscopic structure in which they evolve. Themeasurement of diffusion in biological tissues is therefore of majorimportance in understanding the complex underlying structure that cannotbe studied directly. The Diffusion Tensor Magnetic ResonanceImaging(DTMRI) technique enables the measurement of diffusion parametersand therefore provides information on the structure of the biologicaltissue. This technique has been applied with success to static organssuch as the brain. However, diffusion measurement of dynamicallydeformable organs such as the in-vivo heart remains a complex problem,which holds great potential in determining cardiac health. In order tounderstand the behavior of the magnetic resonance (MR) signal in adeforming media, the Bloch-Torrey equation that defines the MR behavioris expressed in general curvilinear coordinates. These coordinates enableus to follow the heart geometry and deformations through time. Theequation is finally discretized and presented in a numerical formulationusing implicit methods in order to derive a stable scheme that can beapplied to any smooth deformations.
Exact solutions of (n+1)-dimensional Yang-Mills equations in curved space-time
Sanchez-Monroy, J.A.; Quimbay, C.J.
2012-09-15
In the context of a semiclassical approach where vectorial gauge fields can be considered as classical fields, we obtain exact static solutions of the SU(N) Yang-Mills equations in an (n+1)-dimensional curved space-time, for the cases n=1,2,3. As an application of the results obtained for the case n=3, we consider the solutions for the anti-de Sitter and Schwarzschild metrics. We show that these solutions have a confining behavior and can be considered as a first step in the study of the corrections of the spectra of quarkonia in a curved background. Since the solutions that we find in this work are valid also for the group U(1), the case n=2 is a description of the (2+1) electrodynamics in the presence of a point charge. For this case, the solution has a confining behavior and can be considered as an application of the planar electrodynamics in a curved space-time. Finally we find that the solution for the case n=1 is invariant under a parity transformation and has the form of a linear confining solution. - Highlights: Black-Right-Pointing-Pointer We study exact static confining solutions of the SU(N) Yang-Mills equations in an (n+1)-dimensional curved space-time. Black-Right-Pointing-Pointer The solutions found are a first step in the study of the corrections on the spectra of quarkonia in a curved background. Black-Right-Pointing-Pointer A expression for the confinement potential in low dimensionality is found.
Callan-Symanzik equation and asymptotic freedom in the Marr-Shimamoto model
Scarfone, Leonard M.
2010-05-15
The exactly soluble nonrelativistic Marr-Shimamoto model was introduced in 1964 as an example of the Lee model with a propagator and a nontrivial vertex function. An exactly soluble relativistic version of this model, known as the Zachariasen model, has been found to be asymptotically free in terms of coupling constant renormalization at an arbitrary spacelike momentum and on the basis of exact solutions of the Gell-Mann-Low equations. This is accomplished with conventional cut-off regularization by setting up the Yukawa and Fermi coupling constants at Euclidean momenta in terms of on mass-shell couplings and then taking the asymptotic limit. In view of this background, it may be expected that an investigation of the nonrelativistic Marr-Shimamoto theory may also exhibit asymptotic freedom in view of its manifest mathematical similarity to that of the Zachariasen model. To prove this point, the present paper prefers to examine asymptotic freedom in the nonrelativistic Marr-Shimamoto theory using the powerful concepts of the renormalization group and the Callan-Symanzik equation, in conjunction with the specificity of dimensional regularization and on-shell renormalization. This approach is based on calculations of the Callan-Symanzik coefficients and determinations of the effective coupling constants. It is shown that the Marr-Shimamoto theory is asymptotically free for dimensions D<3 and for values of D>3 occurring in periodic intervals over the range of 0
Noise propagation in hybrid models of nonlinear systems: The GinzburgLandau equation
Taverniers, Sren; Alexander, Francis J.; Tartakovsky, Daniel M.
2014-04-01
Every physical phenomenon can be described by multiple models with varying degrees of fidelity. The computational cost of higher fidelity models (e.g., molecular dynamics simulations) is invariably higher than that of their lower fidelity counterparts (e.g., a continuum model based on differential equations). While the former might not be suitable for large-scale simulations, the latter are not universally valid. Hybrid algorithms provide a compromise between the computational efficiency of a coarse-scale model and the representational accuracy of a fine-scale description. This is achieved by conducting a fine-scale computation in subdomains where it is absolutely required (e.g., due to a local breakdown of a continuum model) and coupling it with a coarse-scale computation in the rest of a computational domain. We analyze the effects of random fluctuations generated by the fine-scale component of a nonlinear hybrid on the hybrid's overall accuracy and stability. Two variants of the time-dependent GinzburgLandau equation (GLE) and their discrete representations provided by a nearest-neighbor Ising model serve as a computational testbed. Our analysis shows that coupling these descriptions in a one-dimensional simulation leads to erroneous results. Adding a random source term to the GLE provides accurate prediction of the mean behavior of the quantity of interest (magnetization). It also allows the two GLE variants to correctly capture the strength of the microscale fluctuations. Our work demonstrates the importance of fine-scale noise in hybrid simulations, and suggests the need for replacing an otherwise deterministic coarse-scale component of the hybrid with its stochastic counterpart.
Rare-event Simulation for Stochastic Korteweg-de Vries Equation
Xu, Gongjun; Lin, Guang; Liu, Jingchen
2014-01-01
An asymptotic analysis of the tail probabilities for the dynamics of a soliton wave $U(x,t)$ under a stochastic time-dependent force is developed. The dynamics of the soliton wave $U(x,t)$ is described by the Korteweg-de Vries Equation with homogeneous Dirichlet boundary conditions under a stochastic time-dependent force, which is modeled as a time-dependent Gaussian noise with amplitude $\\epsilon$. The tail probability we considered is $w(b) :=P(\\sup_{t\\in [0,T]} U(x,t) > b ),$ as $b\\rightarrow \\infty,$ for some constant $T>0$ and a fixed $x$, which can be interpreted as tail probability of the amplitude of water wave on shallow surface of a fluid or long internal wave in a density-stratified ocean. Our goal is to characterize the asymptotic behaviors of $w(b)$ and to evaluate the tail probability of the event that the soliton wave exceeds a certain threshold value under a random force term. Such rare-event calculation of $w(b)$ is very useful for fast estimation of the risk of the potential damage that could caused by the water wave in a density-stratified ocean modeled by the stochastic KdV equation. In this work, the asymptotic approximation of the probability that the soliton wave exceeds a high-level $b$ is derived. In addition, we develop a provably efficient rare-event simulation algorithm to compute $w(b)$. The efficiency of the algorithm only requires mild conditions and therefore it is applicable to a general class of Gaussian processes and many diverse applications.
Lehtikangas, O.; Tarvainen, T.; Kim, A.D.; Arridge, S.R.
2015-02-01
The radiative transport equation can be used as a light transport model in a medium with scattering particles, such as biological tissues. In the radiative transport equation, the refractive index is assumed to be constant within the medium. However, in biomedical media, changes in the refractive index can occur between different tissue types. In this work, light propagation in a medium with piece-wise constant refractive index is considered. Light propagation in each sub-domain with a constant refractive index is modeled using the radiative transport equation and the equations are coupled using boundary conditions describing Fresnel reflection and refraction phenomena on the interfaces between the sub-domains. The resulting coupled system of radiative transport equations is numerically solved using a finite element method. The approach is tested with simulations. The results show that this coupled system describes light propagation accurately through comparison with the Monte Carlo method. It is also shown that neglecting the internal changes of the refractive index can lead to erroneous boundary measurements of scattered light.