A Bme Solution Of The Stochastic Three-Dimensional Laplace Equation...
Open Energy Information (Open El) [EERE & EIA]
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.
The nonsinglet structure function evolution by Laplace method
Boroun, G. R. E-mail: boroun@razi.ac.ir; Zarrin, S.
2015-12-15
We derive a general scheme for the evolution of the nonsinglet structure function at the leadingorder (LO) and next-to-leading-order (NLO) by using the Laplace-transform technique. Results for the nonsinglet structure function are compared with MSTW2008, GRV, and CKMT parameterizations and also EMC experimental data in the LO and NLO analysis. The results are in good agreement with the experimental data and other parameterizations in the low- and large-x regions.
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.
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.
Program Manager Office of the Departmental Representative to the Defense Nuclear Facilities Safety Board (DOE DR-1) DOE Headquarters, Forrestal Building 1000 Independence ...
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.
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.
DOE R&D Accomplishments [OSTI]
1998-09-21
In the late 1950s to early 1960s Rudolph A. Marcus developed a theory for treating the rates of outer-sphere electron-transfer reactions. Outer-sphere reactions are reactions in which an electron is transferred from a donor to an acceptor without any chemical bonds being made or broken. (Electron-transfer reactions in which bonds are made or broken are referred to as inner-sphere reactions.) Marcus derived several very useful expressions, one of which has come to be known as the Marcus cross-relation or, more simply, as the Marcus equation. It is widely used for correlating and predicting electron-transfer rates. For his contributions to the understanding of electron-transfer reactions, Marcus received the 1992 Nobel Prize in Chemistry. This paper discusses the development and use of the Marcus equation. Topics include self-exchange reactions; net electron-transfer reactions; Marcus cross-relation; and proton, hydride, atom and group transfers.
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
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...
Resolving the EH{sub 6/7} level in 4H-SiC by Laplace-transform deep level transient spectroscopy
Alfieri, G.; Kimoto, T.
2013-04-15
We show that Laplace transform deep level transient spectroscopy (LDLTS) is an effective technique for the separation of the overlapping emission rates of the EH{sub 6} and EH{sub 7} levels, which are known to constitute EH{sub 6/7}, a mid-gap level in n-type 4H-SiC. The analysis of the electron irradiation dose, electric field dependence, and the effects of carbon interstitials injection on the emission rates of EH{sub 6} and EH{sub 7} shows that EH{sub 7} is dominant over EH{sub 6} and confirms that their nature is related to a carbon vacancy.
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 ...
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.
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.
Set Equation Transformation System.
Energy Science and Technology Software Center (OSTI)
2002-03-22
Version 00 SETS is used for symbolic manipulation of Boolean equations, particularly the reduction of equations by the application of Boolean identities. It is a flexible and efficient tool for performing probabilistic risk analysis (PRA), vital area analysis, and common cause analysis. The equation manipulation capabilities of SETS can also be used to analyze noncoherent fault trees and determine prime implicants of Boolean functions, to verify circuit design implementation, to determine minimum cost fire protectionmore » requirements for nuclear reactor plants, to obtain solutions to combinatorial optimization problems with Boolean constraints, and to determine the susceptibility of a facility to unauthorized access through nullification of sensors in its protection system. Two auxiliary programs, SEP and FTD, are included. SEP performs the quantitative analysis of reduced Boolean equations (minimal cut sets) produced by SETS. The user can manipulate and evaluate the equations to find the probability of occurrence of any desired event and to produce an importance ranking of the terms and events in an equation. FTD is a fault tree drawing program which uses the proprietary ISSCO DISSPLA graphics software to produce an annotated drawing of a fault tree processed by SETS. The DISSPLA routines are not included.« less
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.
General Engineer/Physical Scientist (Facility Representative)
A successful candidate in this position will serve as an on-site senior technical representative, and Facility Representative, with responsibility for evaluating contractor environmental, nuclear...
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 AODR Core Competency Training Worksheet (152.05
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.
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 β, the wave velocity v{sub 0}, and the population of the background free electrons λ. However, it is vice-versa for the deviation from isothermality parameter b, which is in agreement with the result obtained previously.
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. Authorized Property Pass Signers List and Accountable Property Representatives List, Effective April 1, 2016 (106.12 KB) More Documents & Publications Directory Listings AU Functional Area Points of Contact by Office Directors Headquarters Facilities
A Least-Squares Transport Equation Compatible with Voids
Hansen, Jon; Peterson, Jacob; Morel, Jim; Ragusa, Jean; Wang, Yaqi
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
ACMP Handbook Contracting Officer's Representative (COR)
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
ACMP Handbook Contracting Officer's Representative (COR) December 22, 2011 1 Acquisition Career Management Handbook Certification and Appointment of Contracting Officer's Representative (COR) 1. PURPOSE a. U.S. Department of Energy (DOE) DOE has established this Contracting Officer's Representative (COR) Program to outline a comprehensive curriculum to systematically develop skill at performing delegated contract management duties; define competency based training standards to ensure that CORs
DOE ORP Contracting Officer Representatives - Hanford Site
U.S. Department of Energy (DOE) all webpages (Extended Search)
DOE ORP Contracting Officer Representatives Office of River Protection About ORP ORP Projects & Facilities Newsroom Contracts & Procurements ORP Contracts & Procurements Home DOE-ORP Contract Management Plans DOE-ORP Prime Contracts DOE-ORP Contracting Officers DOE ORP Contracting Officer Representatives DOE ORP Purchase Card Buyers Contact ORP DOE ORP Contracting Officer Representatives Email Email Page | Print Print Page | Text Increase Font Size Decrease Font Size DESIGNATED COR
DOE RL Contracting Officer Representatives - Hanford Site
U.S. Department of Energy (DOE) all 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 CHAPIN, DOUGLAS DE-DT0002699 CNG DE-DT0002699, CASCADE NATURAL GAS PIPELINE EIS (DOE/EIS-0476) PHASE 1, WITH
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 ...
FAQS Reference Guide – Facility Representative
Office of Energy Efficiency and Renewable Energy (EERE)
This reference guide addresses the competency statements in the October 2010 edition of DOE-STD-1151-2010, Facility Representative Functional Area Qualification Standard.
Energy Conservation Program for Consumer Products: Representative...
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
This document, concerning the Energy Conservation Program for Consumer Products: Representative Average Unit Costs of Energy, is a notice issued by the Department of Energy. Though ...
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.
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.
Facility Representative Program, Criteria & Review Approach Documents
Office of Energy Efficiency and Renewable Energy (EERE)
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.
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 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
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.
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.
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.
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.
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.
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
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.
Nonextensive Boltzmann Equation and Hadronization
Biro, T.S.; Purcsel, G.
2005-10-14
We present a novel nonextensive generalization of the Boltzmann equation. We investigate the evolution of the one-particle distribution in this framework. The stationary solution is exponential in a nonlinear function of the original energy. The total energy is composed using a general, associative nonextensive rule. We propose that for describing the hadronization of quark matter such rules may apply.
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.
Representing the vacuum polarization on de Sitter
Leonard, Katie E.; Woodard, Richard P.; Prokopec, Tomislav
2013-03-15
Previous studies of the vacuum polarization on de Sitter have demonstrated that there is a simple, noncovariant representation of it in which the physics is transparent. There is also a cumbersome, covariant representation in which the physics is obscure. Despite being unwieldy, the latter form has a powerful appeal for those who are concerned about de Sitter invariance. We show that nothing is lost by employing the simple, noncovariant representation because there is a closed form procedure for converting its structure functions to those of the covariant representation. We also present a vastly improved technique for reading off the noncovariant structure functions from the primitive diagrams. And we discuss the issue of representing the vacuum polarization for a general metric background.
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.
ADVANCED WAVE-EQUATION MIGRATION
L. HUANG; M. C. FEHLER
2000-12-01
Wave-equation migration methods can more accurately account for complex wave phenomena than ray-tracing-based Kirchhoff methods that are based on the high-frequency asymptotic approximation of waves. With steadily increasing speed of massively parallel computers, wave-equation migration methods are becoming more and more feasible and attractive for imaging complex 3D structures. We present an overview of several efficient and accurate wave-equation-based migration methods that we have recently developed. The methods are implemented in the frequency-space and frequency-wavenumber domains and hence they are called dual-domain methods. In the methods, we make use of different approximate solutions of the scalar-wave equation in heterogeneous media to recursively downward continue wavefields. The approximations used within each extrapolation interval include the Born, quasi-Born, and Rytov approximations. In one of our dual-domain methods, we use an optimized expansion of the square-root operator in the one-way wave equation to minimize the phase error for a given model. This leads to a globally optimized Fourier finite-difference method that is a hybrid split-step Fourier and finite-difference scheme. Migration examples demonstrate that our dual-domain migration methods provide more accurate images than those obtained using the split-step Fourier scheme. The Born-based, quasi-Born-based, and Rytov-based methods are suitable for imaging complex structures whose lateral variations are moderate, such as the Marmousi model. For this model, the computational cost of the Born-based method is almost the same as the split-step Fourier scheme, while other methods takes approximately 15-50% more computational time. The globally optimized Fourier finite-difference method significantly improves the accuracy of the split-step Fourier method for imaging structures having strong lateral velocity variations, such as the SEG/EAGE salt model, at an approximately 30% greater
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 1998 Annual Facility Representative Workshop Attendees (82.87 KB) More Documents & Publications 1999 Annual Facility Representative Workshop Attendees FTCP Members DOE Integrated Safety Management Champions List
Germanium multiphase equation of state
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.
W&M Student Elected to Represent American Physical Society's...
U.S. Department of Energy (DOE) all webpages (Extended Search)
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 ...
DOE-STD-1063-2000 - Facility Representatives
Office of Environmental Management (EM)
Joseph Arango, Facility Representative Program Manager Office of the Departmental Representative to the Defense Nuclear Facilities Safety Board (DOE S-3.1), DOE Headquarters, ...
Office of Departmental Representative to DNFSB | Department of...
U.S. Department of Energy (DOE) all webpages (Extended Search)
Office of Departmental Representative to DNFSB Mission The Department Representative to the Defense Nuclear Facilities Safety Board (DNFSB) provides effective cross-organizational ...
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)
Journal Article: Representativeness-Based Sampling Network Design for the State of Alaska Citation Details In-Document Search Title: Representativeness-Based Sampling Network...
4Q CY2000 (PDF), Facility Representative Program Performance...
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
4Q CY2000 (PDF), Facility Representative Program Performance Indicators Quarterly Report 4Q CY2000 (PDF), Facility Representative Program Performance Indicators Quarterly Report ...
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.
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.
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.
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)
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.
Wheeler-DeWitt equation for brane gravity
Gusin, Pawel
2008-03-15
We consider gravity in the system consisting of the Bogomol'nyi-Prasad-Sommerfield (BPS) D3-brane embedded in a flat background geometry, produced by the solutions of supergravity. The effective action for this system is represented by the sum of the Hilbert-Einstein and Dirac-Born-Infeld actions. We derive the Wheeler-DeWitt equation for this system and obtain analytical solutions in some special cases. We also calculate the tunneling probability from the Planckian size of the D3-brane to the classical regime.
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.
1999 FACILITY REPRESENTATIVE CONFERENCE June 21 – 25, 1999
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...
Percent of Commercial Natural Gas Deliveries in California Represented...
U.S. Department of Energy (DOE) all webpages (Extended Search)
California Represented by the Price (Percent) Percent of Commercial Natural Gas Deliveries in California Represented by the Price (Percent) Year Jan Feb Mar Apr May Jun Jul Aug Sep ...
FACILITY REPRESENTATIVE PROGRAM STATUS, 6/21/1999
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...
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 ...
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.
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
1Q CY2000 (PDF), Facility Representative Program Performance Indicators
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
Quarterly Report | Department of Energy Q 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
A solution to Schroder's equation in several variables
Bridges, Robert A.
2016-03-04
For this paper, let φ be an analytic self-map of the n -ball, having 0 as the attracting fixed point and having full-rank near 0. We consider the generalized Schroder's equation, F°φ=φ'(0)kF with ka positive integer and prove there is always a solution F with linearly independent component functions, but that such an F cannot have full rank except possibly when k=1. Furthermore, when k=1 (Schroder's equation), necessary and sufficient conditions on φ are given to ensure F has full rank near 0 without the added assumption of diagonalizability as needed in the 2003 Cowen/MacCluer paper. In response to Enoch'smore » 2007 paper, it is proven that any formal power series solution indeed represents an analytic function on the whole unit ball. Finally, how exactly resonance can lead to an obstruction of a full rank solution is discussed as well as some consequences of having solutions to Schroder's equation.« less
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.
Departmental Representative to the Defense Nuclear Facilities Safety Board
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
(DNFSB) | Department of Energy Departmental Representative to the Defense Nuclear Facilities Safety Board (DNFSB) Departmental Representative to the Defense Nuclear Facilities Safety Board (DNFSB) The Office of the Departmental Representative ensures effective cross-organizational leadership and coordination to resolve DNFSB-identified technical and management issues as we work to ensure the health, safety, and security of the workers, public, and environment. This web site is an important
CNS represented at inaugural Energetics Consortium | Y-12 National Security
U.S. Department of Energy (DOE) all webpages (Extended Search)
Complex 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 | (NNSA) 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
Herbert Richardson: Before The U.S. House of Representatives...
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
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 ...
Dr. Kelli Joseph, NYISO Representing the ISO-RTO Council
Kelli Joseph, NYISO Representing the ISO-RTO Council July 28, 2014 DOE Quadrennial Energy Review Gas Electric Interdependencies: Coordination Efforts, Regional Issues, and...
Appointment of Contracting Officers and Contracting Officer Representatives
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.
Chapter 1: Energy Challenges | Representative DOE Energy and...
Energy and Science Program Workshops ENERGY U.S. DEPARTMENT OF Quadrennial Technology Review 2015 1 Quadrennial Technology Review 2015 Representative DOE Energy and Science Program ...
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.
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.
Equator Appliance: ENERGY STAR Referral (EZ 3720)
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
U.S. Department of Energy (DOE) all 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
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.
Ames Laboratory represented in ISU Homecoming Parade | The Ames Laboratory
U.S. Department of Energy (DOE) all webpages (Extended Search)
represented in ISU Homecoming Parade On Sunday, Oct. 23, a group of about two dozen Ames Laboratory staff marched in the 2016 ISU Homecoming parade through downtown Ames. Marchers distributed candy and 70th anniversary bookmarks to the crowd.
Department of Defense Representatives Visit Hanford to Benchmark Safety
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)...
Changes to the Facility Representative Program, 10/26/1999
Office of Energy Efficiency and Renewable Energy (EERE)
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
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.
Utility Energy Service Contracts Training for Utility Representatives
Office of Energy Efficiency and Renewable Energy (EERE)
This webinar targets Federal staff, as well as utility representatives, and provides an understanding of the legal parameters, contracting requirements, financing options, and other aspects of utility energy service contracts (UESC).
U.S. Representative Frank Lucas and Oklahoma State Senator
U.S. Department of Energy (DOE) all webpages (Extended Search)
3 U.S. Representative Frank Lucas and Oklahoma State Senator David Myers recently voiced ... Though the SGP central facility and activity hub near Lamont, Oklahoma, has 31 employees ...
Radionuclide Interaction and Transport in Representative Geologic Media |
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
Department of Energy Radionuclide Interaction and Transport in Representative Geologic Media Radionuclide Interaction and Transport in Representative Geologic Media The report presents information related to the development of a fundamental understanding of disposal-system performance in a range of environments for potential wastes that could arise from future nuclear fuel cycle alternatives. It addresses selected aspects of the development of computational modeling capability for the
DOE Representative to World Institute of Nuclear Safety (WINS) | National
National Nuclear Security Administration (NNSA)
Nuclear Security Administration | (NNSA) 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
On the relationship between ODE solvers and iterative solvers for linear equations
Lorber, A.; Joubert, W.; Carey, G.F.
1994-12-31
The connection between the solution of linear systems of equations by both iterative methods and explicit time stepping techniques is investigated. Based on the similarities, a suite of Runge-Kutta time integration schemes with extended stability domains are developed using Chebyshev iteration polynomials. These Runge-Kutta schemes are applied to linear and non-linear systems arising from the numerical solution of PDE`s containing either physical or artificial transient terms. Specifically, the solutions of model linear convection and convection-diffusion equations are presented, as well as the solution of a representative non-linear Navier-Stokes fluid flow problem. Included are results of parallel computations.
Second order upwind Lagrangian particle method for Euler equations
Samulyak, Roman; Chen, Hsin -Chiang; Yu, Kwangmin
2016-06-01
A new second order upwind Lagrangian particle method for solving Euler equations for compressible inviscid fluid or gas flows is proposed. Similar to smoothed particle hydrodynamics (SPH), the method represents fluid cells with Lagrangian particles and is suitable for the simulation of complex free surface / multiphase flows. The main contributions of our method, which is different from SPH in all other aspects, are (a) significant improvement of approximation of differential operators based on a polynomial fit via weighted least squares approximation and the convergence of prescribed order, (b) an upwind second-order particle-based algorithm with limiter, providing accuracy and longmore » term stability, and (c) accurate resolution of states at free interfaces. In conclusion, numerical verification tests demonstrating the convergence order for fixed domain and free surface problems are presented.« less
Equator: Order (2015-CE-20007) | Department of Energy
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
Equator: Order (2015-CE-20007) Equator: Order (2015-CE-20007) August 9, 2016 DOE ordered Equator Advanced Appliances to pay a $8,000 civil penalty after finding Equator had failed to certify that certain residential clothes washers and residential clothes dryers comply with the applicable energy conservation standards. The Order adopted a Compromise Agreement, which reflected settlement terms between DOE and Equator. DOE alleged in a March 1, 2016 Notice of Proposed Civil Penalty that Equator
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.
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...
Probability Density Function Method for Langevin Equations with...
Office of Scientific and Technical Information (OSTI)
Probability Density Function Method for Langevin Equations with Colored Noise Citation Details In-Document Search Title: Probability Density Function Method for Langevin Equations ...
Probability Density Function Method for Langevin Equations with...
Office of Scientific and Technical Information (OSTI)
Language: English Subject: PDF method, uncertainty quantification, Langevin equation, Fokker-Planck equation, colored-noise, Large-Eddy-Diffusivity approximation Word Cloud More ...
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 ...
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 ...
Iterative solution of Hermite boundary integral equations (Journal...
Office of Scientific and Technical Information (OSTI)
Iterative solution of Hermite boundary integral equations Citation Details In-Document Search Title: Iterative solution of Hermite boundary integral equations An efficient ...
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.
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.
Ultra Deep Wave Equation Imaging and Illumination
Alexander M. Popovici; Sergey Fomel; Paul Sava; Sean Crawley; Yining Li; Cristian Lupascu
2006-09-30
In this project we developed and tested a novel technology, designed to enhance seismic resolution and imaging of ultra-deep complex geologic structures by using state-of-the-art wave-equation depth migration and wave-equation velocity model building technology for deeper data penetration and recovery, steeper dip and ultra-deep structure imaging, accurate velocity estimation for imaging and pore pressure prediction and accurate illumination and amplitude processing for extending the AVO prediction window. Ultra-deep wave-equation imaging provides greater resolution and accuracy under complex geologic structures where energy multipathing occurs, than what can be accomplished today with standard imaging technology. The objective of the research effort was to examine the feasibility of imaging ultra-deep structures onshore and offshore, by using (1) wave-equation migration, (2) angle-gathers velocity model building, and (3) wave-equation illumination and amplitude compensation. The effort consisted of answering critical technical questions that determine the feasibility of the proposed methodology, testing the theory on synthetic data, and finally applying the technology for imaging ultra-deep real data. Some of the questions answered by this research addressed: (1) the handling of true amplitudes in the downward continuation and imaging algorithm and the preservation of the amplitude with offset or amplitude with angle information required for AVO studies, (2) the effect of several imaging conditions on amplitudes, (3) non-elastic attenuation and approaches for recovering the amplitude and frequency, (4) the effect of aperture and illumination on imaging steep dips and on discriminating the velocities in the ultra-deep structures. All these effects were incorporated in the final imaging step of a real data set acquired specifically to address ultra-deep imaging issues, with large offsets (12,500 m) and long recording time (20 s).
Jin, Shi; Xiu, Dongbin; Zhu, Xueyu
2015-05-15
In this paper we develop a set of stochastic numerical schemes for hyperbolic and transport equations with diffusive scalings and subject to random inputs. The schemes are asymptotic preserving (AP), in the sense that they preserve the diffusive limits of the equations in discrete setting, without requiring excessive refinement of the discretization. Our stochastic AP schemes are extensions of the well-developed deterministic AP schemes. To handle the random inputs, we employ generalized polynomial chaos (gPC) expansion and combine it with stochastic Galerkin procedure. We apply the gPC Galerkin scheme to a set of representative hyperbolic and transport equations and establish the AP property in the stochastic setting. We then provide several numerical examples to illustrate the accuracy and effectiveness of the stochastic AP schemes.
Appointment of Contracting Officers and Contracting Officer's Representatives
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.
WIPP Representative Selected For National Environmental Justice Advisory Board
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.
Facility Representative Qualification Equivalencies Based on Previous Experience
The purpose of this Memorandum is to provide guidance, Attachment 1, to Qualifying Officials (QO) on how to use the cross-walk, Attachment 2, in granting equivalencies to Facility Representative (FR) candidates using the most current FR Functional Area Qualification Standards, DOE-STD-1151-2010.
Dark soliton solution of Sasa-Satsuma equation
Ohta, Y.
2010-03-08
The Sasa-Satsuma equation is a higher order nonlinear Schroedinger type equation which admits bright soliton solutions with internal freedom. We present the dark soliton solutions for the equation by using Gram type determinant. The dark solitons have no internal freedom and exist for both defocusing and focusing equations.
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
Wang, Chi-Jen
2013-01-01
In this thesis, we analyze both the spatiotemporal behavior of: (A) non-linear “reaction” models utilizing (discrete) reaction-diffusion equations; and (B) spatial transport problems on surfaces and in nanopores utilizing the relevant (continuum) diffusion or Fokker-Planck equations. Thus, there are some common themes in these studies, as they all involve partial differential equations or their discrete analogues which incorporate a description of diffusion-type processes. However, there are also some qualitative differences, as shall be discussed below.
Crosta, M.; Fratalocchi, A.; Trillo, S.
2011-12-15
We characterize the full family of soliton solutions sitting over a background plane wave and ruled by the cubic-quintic nonlinear Schroedinger equation in the regime where a quintic focusing term represents a saturation of the cubic defocusing nonlinearity. We discuss the existence and properties of solitons in terms of catastrophe theory and fully characterize bistability and instabilities of the dark-antidark pairs, revealing mechanisms of decay of antidark solitons into dispersive shock waves.
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.
A multigrid preconditioner for the semiconductor equations
Meza, J.C.; Tuminaro, R.S.
1994-12-31
Currently, integrated circuits are primarily designed in a {open_quote}trial and error{close_quote} fashion. That is, prototypes are built and improved via experimentation and testing. In the near future, however, it may be possible to significantly reduce the time and cost of designing new devices by using computer simulations. To accurately perform these complex simulations in three dimensions, however, new algorithms and high performance computers are necessary. In this paper the authors discuss the use of multigrid preconditioning inside a semiconductor device modeling code, DANCIR. The DANCIR code is a full three-dimensional simulator capable of computing steady-state solutions of the drift-diffusion equations for a single semiconductor device and has been used to simulate a wide variety of different devices. At the inner core of DANCIR is a solver for the nonlinear equations that arise from the spatial discretization of the drift-diffusion equations on a rectangular grid. These nonlinear equations are resolved using Gummel`s method which requires three symmetric linear systems to be solved within each Gummel iteration. It is the resolution of these linear systems which comprises the dominant computational cost of this code. The original version of DANCIR uses a Cholesky preconditioned conjugate gradient algorithm to solve these linear systems. Unfortunately, this algorithm has a number of disadvantages: (1) it takes many iterations to converge (if it converges), (2) it can require a significant amount of computing time, and (3) it is not very parallelizable. To improve the situation, the authors consider a multigrid preconditioner. The multigrid method uses iterations on a hierarchy of grids to accelerate the convergence on the finest grid.
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)
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.
James A. MacLachlan
2001-07-12
Numerical simulations of cooling processes over minutes or hours of real time are usually carried out using direct solution of the Fokker-Planck equation. However, by using scaling rules derived from that equation, it is possible to use macroparticle representations of the beam distribution. Besides having applications for cooling alone, the macroparticle approach allows combining the cooling process with other dynamical processes which are represented by area-preserving maps. A time-scaling rule derived from the Vlasov equation can be used to adjust the time step of a map-based dynamics calculation to one more suitable for combining with a macroparticle Fokker-Planck calculation. The time scaling for the Vlasov equation is also useful for substantially more rapid calculations when a macroparticle model of a conservative multiparticle system requires a large number of macroparticles to faithfully produce the collective potential or when the model must simulate a long time period.
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 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
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
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.
The equation of motion of an electron
Kim, K.; Sessler, A.M.
1999-07-01
We review the current status of understanding of the equation of motion of an electron. Classically, a consistent, linearized theory exists for an electron of finite extent, as long as the size of the electron is larger than the classical electron radius. Nonrelativistic quantum mechanics seems to offer a fine theory even in the point particle limit. Although there is as yet no convincing calculation, it is probable that a quantum electrodynamical result will be at least as well-behaved as is the nonrelativistic quantum mechanical results. {copyright} {ital 1999 American Institute of Physics.}
Efficient solution of the simplified PN equations
Hamilton, Steven P.; Evans, Thomas M.
2014-12-23
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. Moreover, 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. These 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 than Arnoldi's method.
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.
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
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
Propagation of ultra-short solitons in stochastic Maxwell's equations
Kurt, Levent; Schäfer, 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.
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 ...
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.
Equations for plutonium and americium-241 decay corrections ...
Office of Scientific and Technical Information (OSTI)
PLUTONIUM; ACCOUNTING; CORRECTIONS; DIFFERENTIAL EQUATIONS; ISOTOPE RATIO; NUCLEAR MATERIALS MANAGEMENT; TIME DEPENDENCE; ACTINIDE ISOTOPES; ACTINIDE NUCLEI; ACTINIDES; ALPHA ...
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.
Conservation properties and potential systems of vorticity-type equations
Cheviakov, Alexei F.
2014-03-15
Partial differential equations of the form divN=0, N{sub t}+curl M=0 involving two vector functions in R{sup 3} depending on t, x, y, z appear in different physical contexts, including the vorticity formulation of fluid dynamics, magnetohydrodynamics (MHD) equations, and Maxwell's equations. It is shown that these equations possess an infinite family of local divergence-type conservation laws involving arbitrary functions of space and time. Moreover, it is demonstrated that the equations of interest have a rather special structure of a lower-degree (degree two) conservation law in R{sup 4}(t,x,y,z). The corresponding potential system has a clear physical meaning. For the Maxwell's equations, it gives rise to the scalar electric and the vector magnetic potentials; for the vorticity equations of fluid dynamics, the potentialization inverts the curl operator to yield the fluid dynamics equations in primitive variables; for MHD equations, the potential equations yield a generalization of the Galas-Bogoyavlenskij potential that describes magnetic surfaces of ideal MHD equilibria. The lower-degree conservation law is further shown to yield curl-type conservation laws and determined potential equations in certain lower-dimensional settings. Examples of new nonlocal conservation laws, including an infinite family of nonlocal material conservation laws of ideal time-dependent MHD equations in 2+1 dimensions, are presented.
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.
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
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.
Wave propagation in equivalent continuums representing truss lattice materials
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
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.
Complete Mie-Gruneisen Equation of State
Menikoff, Ralph
2012-06-28
The Mie-Gruneisen equation of state (EOS) is frequently used in hydro simulations to model solids at high pressure (up to a few Mb). It is an incomplete EOS characterized by a Gruneisen coefficient, {Lambda} = -V({partial_derivative}{sub e}P){sub V}, that is a function of only V. Expressions are derived for isentropes and isotherms. This enables the extension to a complete EOS. Thermodynamic consistency requires that the specific heat is a function of a single scaled temperature. A complete extension is uniquely determined by the temperature dependence of the specific heat at a fixed reference density. In addition we show that if the domain of the EOS extends to T = 0 and the specific heat vanishes on the zero isotherm then {Lambda} a function of only V is equivalent to a specific heat with a single temperature scale. If the EOS domain does not include the zero isotherm, then a specific heat with a single temperature scale leads to a generalization of the Mie-Gruneisen EOS in which the pressure is linear in both the specific energy and the temperature. Such an EOS has previously been used to model liquid nitromethane.
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.
Exponentially-convergent Monte Carlo for the 1-D transport equation
Peterson, J. R.; Morel, J. E.; Ragusa, J. C.
2013-07-01
We define a new exponentially-convergent Monte Carlo method for solving the one-speed 1-D slab-geometry transport equation. This method is based upon the use of a linear discontinuous finite-element trial space in space and direction to represent the transport solution. A space-direction h-adaptive algorithm is employed to restore exponential convergence after stagnation occurs due to inadequate trial-space resolution. This methods uses jumps in the solution at cell interfaces as an error indicator. Computational results are presented demonstrating the efficacy of the new approach. (authors)
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
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 ...
Power-law spatial dispersion from fractional Liouville equation
Tarasov, Vasily E.
2013-10-15
A microscopic model in the framework of fractional kinetics to describe spatial dispersion of power-law type is suggested. The Liouville equation with the Caputo fractional derivatives is used to obtain the power-law dependence of the absolute permittivity on the wave vector. The fractional differential equations for electrostatic potential in the media with power-law spatial dispersion are derived. The particular solutions of these equations for the electric potential of point charge in this media are considered.
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.
A new least-squares transport equation compatible with voids
Hansen, J. B.; Morel, J. E.
2013-07-01
We define a new least-squares transport equation that is applicable in voids, can be solved using source iteration with diffusion-synthetic acceleration, and requires only the solution of an independent set of second-order self-adjoint equations for each direction during each source iteration. We derive the equation, discretize it using the S{sub n} method in conjunction with a linear-continuous finite-element method in space, and computationally demonstrate various of its properties. (authors)
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.
An Acoustic Wave Equation for Tilted Transversely Isotropic Media...
Office of Scientific and Technical Information (OSTI)
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 ...
Adjoint Fokker-Planck equation and runaway electron dynamics...
Office of Scientific and Technical Information (OSTI)
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 ...
Penetration equations Young, C.W. [Applied Research Associates...
Office of Scientific and Technical Information (OSTI)
45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEFENSE; EARTH PENETRATORS; EQUATIONS; NUCLEAR WEAPONS; SOILS; ICE; ROCKS; CONCRETES; PERMAFROST; SCALING LAWS In 1967, Sandia...
Felix Bloch, Nuclear Induction, Bloch Equations, Bloch Theorem...
Office of Scientific and Technical Information (OSTI)
... Landmarks: NMR-- Grandmother of MRI, American Physical Society (APS) Chronology - Bloch (Felix) Papers; Online Archive of California, Stanford University Archives Bloch Equations ...
Felix Bloch, Nuclear Induction, Bloch Equations, Bloch Theorem...
Office of Scientific and Technical Information (OSTI)
Felix Bloch, Nuclear Induction, and Bloch Equations Resources with Additional Information ... for the 'development of new methods for nuclear magnetic precision measurements and ...
Scientists compose complex math equations to replicate behaviors...
U.S. Department of Energy (DOE) all webpages (Extended Search)
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...
Office of Scientific and Technical Information (OSTI)
Technical Report: Solving the power flow equations: a monotone operator approach Citation ... In this paper, we solve this problem using the theory of monotone operators. We show that ...
SCIENCE ON SATURDAY- "Disastrous Equations: The Role of Mathematics...
U.S. Department of Energy (DOE) all webpages (Extended Search)
SCIENCE ON SATURDAY- "Disastrous Equations: The Role of Mathematics in Understanding Tsunami" Professor J. Douglas Wright, Associate Professor Department of Mathematics, Drexel ...
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 ρ as ρ=±√(l)
Specificity and completion time distributions of biochemical...
Office of Scientific and Technical Information (OSTI)
Journal Article: Specificity and completion time distributions of ... Using the Laplace transform of the corresponding chemical master equation, we obtain an analytical solution for the ...
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.
Changing the Equation in STEM Education | Department of Energy
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
Equation in STEM Education Changing the Equation in STEM Education September 20, 2010 - 11:34am Addthis Katelyn Sabochik 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
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}
Time-dependent closure relations for relativistic collisionless fluid equations
Bendib-Kalache, K.; Bendib, A.; El Hadj, K. Mohammed
2010-11-15
Linear fluid equations for relativistic and collisionless plasmas are derived. Closure relations for the fluid equations are analytically computed from the relativistic Vlasov equation in the Fourier space ({omega},k), where {omega} and k are the conjugate variables of time t and space x variables, respectively. The mathematical method used is based on the projection operator techniques and the continued fraction mathematical tools. The generalized heat flux and stress tensor are calculated for arbitrary parameter {omega}/kc where c is the speed of light, and for arbitrary relativistic parameter z=mc{sup 2}/T, where m is the particle rest mass and T, the plasma temperature in energy units.
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.
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.
... Guidance for Hazard Analysis-Emergency Planning for Extremely Hazardous Substances; or ... DOE-STD-1063-2011 13 f. Minor events or problems are frequently clues that indicate ...
Josh Allen of Richland Operations Office Named 2014 Facility Representative of the Year
Congratulations to Josh Allen, Richland Operations Office, the winner of the 2014 DOE Facility Representative of the Year Award!
Electrolux Gibson Air Conditioner and Equator Clothes Washer...
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...
Numerical solution of control problems governed by nonlinear differential equations
Heinkenschloss, M.
1994-12-31
In this presentation the author investigates an iterative method for the solution of optimal control problems. These problems are formulated as constrained optimization problems with constraints arising from the state equation and in the form of bound constraints on the control. The method for the solution of these problems uses the special structure of the problem arising from the bound constraint and the state equation. It is derived from SQP methods and projected Newton methods and combines the advantages of both methods. The bound constraint is satisfied by all iterates using a projection, the nonlinear state equation is satisfied in the limit. Only a linearized state equation has to be solved in every iteration. The solution of the linearized problems are done using multilevel methods and GMRES.
Equator Appliance: ENERGY STAR Referral (EZ 3720 CEE)
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.
Constraining the equation of state of superhadronic matter from...
Office of Scientific and Technical Information (OSTI)
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 ...
Green Computing Helps in Zero Energy Equation - News Feature...
U.S. Department of Energy (DOE) all webpages (Extended Search)
Green Computing Helps in Zero Energy Equation April 14, 2010 Photo of two men watching as a third man goes over blueprints in the data center of NREL's Research Support Facility. ...
Accuracy-based time step criteria for solving parabolic equations
Mohtar, R.; Segerlind, L.
1995-12-31
Parabolic equations govern many transient engineering problems. Space integration using finite element or finite difference methods changes the parabolic partial differential equation into an ordinary differential equation. Time integration schemes are needed to solve the later equation. In order to accurately perform the later integration a proper time step must be provided. Time step estimates based on a stability criteria have been prescribed in the literature. The following paper presents time step estimates that satisfy stability as well as accuracy criteria. These estimates were correlated to the Froude and Courant Numbers. The later criteria were found to be overly conservative for some integration schemes. Suggestions as to which time integration scheme is the best to use are also presented.
An evolution equation modeling inversion of tulip flames
Dold, J.W.; Joulin, G.
1995-02-01
The authors attempt to reduce the number of physical ingredients needed to model the phenomenon of tulip-flame inversion to a bare minimum. This is achieved by synthesizing the nonlinear, first-order Michelson-Sivashinsky (MS) equation with the second order linear dispersion relation of Landau and Darrieus, which adds only one extra term to the MS equation without changing any of its stationary behavior and without changing its dynamics in the limit of small density change when the MS equation is asymptotically valid. However, as demonstrated by spectral numerical solutions, the resulting second-order nonlinear evolution equation is found to describe the inversion of tulip flames in good qualitative agreement with classical experiments on the phenomenon. This shows that the combined influences of front curvature, geometric nonlinearity and hydrodynamic instability (including its second-order, or inertial effects, which are an essential result of vorticity production at the flame front) are sufficient to reproduce the inversion process.
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.
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.
Absorbing boundary conditions for relativistic quantum mechanics equations
Antoine, X.; Sater, J.; Fillion-Gourdeau, F.; Bandrauk, A.D.
2014-11-15
This paper is devoted to the derivation of absorbing boundary conditions for the Klein–Gordon and Dirac equations modeling quantum and relativistic particles subject to classical electromagnetic fields. Microlocal analysis is the main ingredient in the derivation of these boundary conditions, which are obtained in the form of pseudo-differential equations. Basic numerical schemes are derived and analyzed to illustrate the accuracy of the derived boundary conditions.
What every designated representative should know about Title IV and Title V enforcement provisions
Bischoff, C.A.; Dayal, P.
1995-12-31
Title IV of the Clean Air Act not only created a regulatory program unlike any other under the Clean Air Act, but also established a unique position--the designated representative--as an integral part of the program. The designated representative is required to meet certain basic obligations under Title IV, and a panoply of enforcement mechanisms are available to EPA in the event of noncompliance with these obligations. Also, because a designated representative may take on responsibilities under the permit provisions of Title V of the Clean Air Act, the designated representative can also be subject to an enforcement action for failure to comply with certain Title V permit requirements. This paper considers the basic definition of the designated representative under EPA`s Title IV and Title V regulations, identifies the responsibilities assigned to the designated representative, and then analyzes the enforcement mechanisms that may be applied to the designated representative if a regulatory responsibility has not been satisfied.
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?
Westerhof, E. Pratt, J.
2014-10-15
In the presence of electron cyclotron current drive (ECCD), the Ohm's law of single fluid magnetohydrodynamics is modified as E + v × B = η(J – J{sub EC}). This paper presents a new closure relation for the EC driven current density appearing in this modified Ohm's law. The new relation faithfully represents the nonlocal character of the EC driven current and its main origin in the Fisch-Boozer effect. The closure relation is validated on both an analytical solution of an approximated Fokker-Planck equation as well as on full bounce-averaged, quasi-linear Fokker-Planck code simulations of ECCD inside rotating magnetic islands. The new model contains the model put forward by Giruzzi et al. [Nucl. Fusion 39, 107 (1999)] in one of its limits.
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.
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.
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.
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
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
Bifurcations of traveling wave solutions for an integrable equation
Li Jibin; Qiao Zhijun
2010-04-15
This paper deals with the following equation m{sub t}=(1/2)(1/m{sup k}){sub xxx}-(1/2)(1/m{sup k}){sub x}, which is proposed by Z. J. Qiao [J. Math. Phys. 48, 082701 (2007)] and Qiao and Liu [Chaos, Solitons Fractals 41, 587 (2009)]. By adopting the phase analysis method of planar dynamical systems and the theory of the singular traveling wave systems to the traveling wave solutions of the equation, it is shown that for different k, the equation may have infinitely many solitary wave solutions, periodic wave solutions, kink/antikink wave solutions, cusped solitary wave solutions, and breaking loop solutions. We discuss in a detail the cases of k=-2,-(1/2),(1/2),2, and parametric representations of all possible bounded traveling wave solutions are given in the different (c,g)-parameter regions.
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.
Translationally invariant conservation laws of local Lindblad equations
Žnidarič, Marko; Benenti, Giuliano; Casati, Giulio
2014-02-15
We study the conditions under which one can conserve local translationally invariant operators by local translationally invariant Lindblad equations in one-dimensional rings of spin-1/2 particles. We prove that for any 1-local operator (e.g., particle density) there exist Lindblad dissipators that conserve that operator, while on the other hand we prove that among 2-local operators (e.g., energy density) only trivial ones of the Ising type can be conserved, while all the other cannot be conserved, neither locally nor globally, by any 2- or 3-local translationally invariant Lindblad equation. Our statements hold for rings of any finite length larger than some minimal length determined by the locality of Lindblad equation. These results show in particular that conservation of energy density in interacting systems is fundamentally more difficult than conservation of 1-local quantities.
Combinatorial approach to Mathieu and Lamé equations
He, Wei
2015-07-15
Based on some recent progress on a relation between four dimensional super Yang-Mills gauge theory and quantum integrable system, we study the asymptotic spectrum of the quantum mechanical problems described by the Mathieu equation and the Lamé equation. The large momentum asymptotic expansion of the eigenvalue is related to the instanton partition function of supersymmetric gauge theories which can be evaluated by a combinatorial method. The electro-magnetic duality of gauge theory indicates that in the parameter space, there are three asymptotic expansions for the eigenvalue, and we confirm this fact by performing the Wentzel–Kramers–Brillouin (WKB) analysis in each asymptotic expansion region. The results presented here give some new perspective on the Floquet theory about periodic differential equation.
Secretary Chu to Join Representatives Lofgren and Honda at the SLAC
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
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
Gregory H. Friedman: Before The U.S. House of Representatives Committee on
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
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
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 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
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 U.S. House 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, 2002 Before the U.S. House of Representatives Committee on Energy and Commerce Subcommittee on Oversight and Investigations Statement of Gregory H.
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.
3Q CY2007 (PDF), Facility Representative Program Performance Indicators Quarterly Report
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...
3Q CY2000 (PDF), Facility Representative Program Performance Indicators Quarterly Report
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...
DOE-STD-1151-2002; Facility Representative Functional Area Qualificati...
DOE STANDARD FACILITY REPRESENTATIVE FUNCTIONAL AREA QUALIFICATION STANDARD DOE Defense Nuclear Facilities Technical Personnel U.S. Department of Energy AREA TRNG Washington, D.C. ...
2Q CY2008 (PDF), Facility Representative Program Performance Indicators Quarterly Report
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...
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 Government ... Organization Statement of Gregory H. Friedman, Inspector General U.S. Department of ...
Gregory H. Friedman: Before the U.S. House of Representatives...
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
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 ...
2Q CY2006 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Office of Energy Efficiency and Renewable Energy (EERE)
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 CY2002 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Office of Energy Efficiency and Renewable Energy (EERE)
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...
3Q CY2005 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Office of Energy Efficiency and Renewable Energy (EERE)
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 CY2005 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Office of Energy Efficiency and Renewable Energy (EERE)
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...
DOE Orders Self-Study Program- DOE-STD-1063-2011, Facility Representatives
U.S. Department of Energy Orders Self-Study Program DOE-STD-1063-2011, Facility Representatives Familiar Level - August 2011
Tailored Marketing for Low-income and Under-Represented Population Segments (201)
Better Buildings Residential Network Peer Exchange Call Series: Tailored Marketing for Low-Income and Under-Represented Population Segments (201), call slides and discussion summary.
2Q CY2005 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Office of Energy Efficiency and Renewable Energy (EERE)
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 CY2012 (PDF), Facility Representative Program Performance Indicators Quarterly Report
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 CY2005 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Office of Energy Efficiency and Renewable Energy (EERE)
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...
4Q CY2010 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Office of Energy Efficiency and Renewable Energy (EERE)
"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...
2Q CY2007 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Office of Energy Efficiency and Renewable Energy (EERE)
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...
1Q CY2007 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Office of Energy Efficiency and Renewable Energy (EERE)
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...
3Q CY2010 (PDF), Facility Representative Program Performance Indicators Quarterly Report
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...
4Q CY2011 (PDF), Facility Representative Program Performance Indicators Quarterly Report
"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
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...
4Q CY2006 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Office of Energy Efficiency and Renewable Energy (EERE)
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 CY2011 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Office of Energy Efficiency and Renewable Energy (EERE)
"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...
1Q CY2011 (PDF), Facility Representative Program Performance Indicators Quarterly Report
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
Office of Energy Efficiency and Renewable Energy (EERE)
"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 CY2011 (PDF), Facility Representative Program Performance Indicators Quarterly Report
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...
2Q CY2010 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Office of Energy Efficiency and Renewable Energy (EERE)
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...
4Q CY2007 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Office of Energy Efficiency and Renewable Energy (EERE)
"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...
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.
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.
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 of liquid Indium under high pressure
Li, Huaming E-mail: mo.li@gatech.edu; Li, Mo E-mail: mo.li@gatech.edu; Sun, Yongli
2015-09-15
We apply an equation of state of a power law form to liquid Indium to study its thermodynamic properties under high temperature and high pressure. Molar volume of molten indium is calculated along the isothermal line at 710K within good precision as compared with the experimental data in an externally heated diamond anvil cell. Bulk modulus, thermal expansion and internal pressure are obtained for isothermal compression. Other thermodynamic properties are also calculated along the fitted high pressure melting line. While our results suggest that the power law form may be a better choice for the equation of state of liquids, these detailed predictions are yet to be confirmed by further experiment.
Hamiltonian time integrators for Vlasov-Maxwell equations
He, Yang; Xiao, Jianyuan; Zhang, Ruili; Liu, Jian; Qin, Hong; Sun, Yajuan
2015-12-15
Hamiltonian time integrators for the Vlasov-Maxwell equations are developed by a Hamiltonian splitting technique. The Hamiltonian functional is split into five parts, which produces five exactly solvable subsystems. Each subsystem is a Hamiltonian system equipped with the Morrison-Marsden-Weinstein Poisson bracket. Compositions of the exact solutions provide Poisson structure preserving/Hamiltonian methods of arbitrary high order for the Vlasov-Maxwell equations. They are then accurate and conservative over a long time because of the Poisson-preserving nature.
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.
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.
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.
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.
Mass distribution from a quark matter equation of state
Biro, T. S.; Levai, P.; Van, P.; Zimanyi, J.
2007-03-15
We analyze the equation of state in terms of quasiparticles with continuously distributed mass. We seek for a description of the entire pressure-temperature curve at vanishing chemical potential in terms of a temperature independent mass distribution. We point out properties indicating a mass gap in this distribution, conjectured to be related to confinement.
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.
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.
Non-commutative relativistic equation with a Coulomb potential
Zaim, Slimane; Khodja, Lamine; Delenda, Yazid
2012-06-27
We improve the previous study of the Klein-Gordon equation in a non-commutative space-time as applied to the Hydrogen atom to extract the energy levels, by considering the secondorder corrections in the non-commutativity parameter. Phenomenologically we show that noncommutativity plays the role of spin.
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%.
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.
Methods for diffusive relaxation in the Pn equation
Hauck, Cory D; Mcclarren, Ryan G; Lowrie, Robert B
2008-01-01
We present recent progress in the development of two substantially different approaches for simulating the so-called of P{sub N} equations. These are linear hyperbolic systems of PDEs that are used to model particle transport in a material medium, that in highly collisional regimes, are accurately approximated by a simple diffusion equation. This limit is based on a balance between function values and gradients of certain variables in the P{sub N} system. Conventional reconstruction methods based on upwinding approximate such gradients with an error that is dependent on the size of the computational mesh. Thus in order to capture the diffusion limit, a given mesh must resolve the dynamics of the continuum equation at the level of the mean-free-path, which tends to zero in the diffusion limit. The two methods analyzed here produce accurate solutions in both collisional and non-collisional regimes; in particular, they do not require resolution of the mean-free-path in order to properly capture the diffusion limit. The first method is a straight-forward application of the discrete Galerkin (DG) methodology, which uses additional variables in each computational cell to capture the balance between function values and gradients, which are computed locally. The second method uses a temporal splitting of the fast and slow dynamics in the P{sub N} system to derive so-called regularized equations for which the diffusion limit is built-in. We focus specifically on the P{sub N} equations for one-dimensional, slab geometries. Preliminary results for several benchmark problems are presented which highlight the advantages and disadvantages of each method. Further improvements and extensions are also discussed.
Iterative solvers for Navier-Stokes equations: Experiments with turbulence model
Page, M.; Garon, A.
1994-12-31
In the framework of developing software for the prediction of flows in hydraulic turbine components, Reynolds averaged Navier-Stokes equations coupled with {kappa}-{omega} two-equation turbulence model are discretized by finite element method. Since the resulting matrices are large, sparse and nonsymmetric, strategies based on CG-type iterative methods must be devised. A segregated solution strategy decouples the momentum equation, the {kappa} transport equation and the {omega} transport equation. These sets of equations must be solved while satisfying constraint equations. Experiments with orthogonal projection method are presented for the imposition of essential boundary conditions in a weak sense.
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
Sensitivity and representativity analysis of past experiments with respect to ABTR system.
Aliberti, G.; Palmiotti, G.; Salvatores, M.
2007-08-29
A comprehensive validation analysis has been performed that incorporates representativity of multiple parameters, experiments, reference designs, and adjustment of the nuclear data. The work involves a new representativity study among selected reactor designs and several experiments. Application, using existing experiments, to reference design like the ABTR and the SFR has demonstrated that it is possible to achieve a significant reduction of uncertainty on the main integral parameters of interest for their neutronic design. This is possible when the set of available experiments are relevant (i.e. representative of the reference designs), of good quality (i.e. of reduced uncertainty on experimental results), and consistent (i.e. not providing conflictive information).
3Q CY2009 (PDF), Facility Representative Program Performance Indicators Quarterly Report
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...
4Q CY2009 (PDF), Facility Representative Program Performance Indicators Quarterly Report
"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...
2Q CY2009 (PDF), Facility Representative Program Performance Indicators Quarterly Report
"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...
2Q CY2000 (PDF), Facility Representative Program Performance Indicators Quarterly Report
"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...
1Q CY2009 (PDF), Facility Representative Program Performance Indicators Quarterly Report
"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...
3Q C&2008 (PDF), Facility Representative Program Performance Indicators Quarterly Report
"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...
John C. Barnes of Savannah River Operations named 2012 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. Each year the Department...
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 ... Statement of Gregory H. Friedman Inspector General, U.S. Department of Energy Request to ...
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 ...
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 Request to ...
1Q CY2010 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Office of Energy Efficiency and Renewable Energy (EERE)
"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 CY2003 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Office of Energy Efficiency and Renewable Energy (EERE)
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...
1Q CY2003 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Office of Energy Efficiency and Renewable Energy (EERE)
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 CY2003 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Office of Energy Efficiency and Renewable Energy (EERE)
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...
4Q CY2004 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Office of Energy Efficiency and Renewable Energy (EERE)
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...
2Q CY2004 (PDF), Facility Representative Program Performance Indicators Quarterly Report
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...
4Q CY2003 (PDF), Facility Representative Program Performance Indicators Quarterly Report
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 CY2004 (PDF), Facility Representative Program Performance Indicators Quarterly Report
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...
U.S. Energy Secretary Steven Chu, U.S. Representatives Larson...
U.S. Representative Joe Courtney WHAT: Tour of United Technologies Research Center WHEN: 9:45 AM EST **Media availability to follow Media are requested to park in the lot ...
Stan Watkins Named Department of Energy Facility Representative of the Year
National Nuclear Security Administration (NNSA)
| National Nuclear Security Administration | (NNSA) Stan Watkins Named Department of Energy Facility Representative of the Year May 15, 2009 Microsoft Office document icon R-09-02
1Q CY2006 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Office of Energy Efficiency and Renewable Energy (EERE)
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...
4Q CY2008 (PDF), Facility Representative Program Performance Indicators Quarterly Report
Office of Energy Efficiency and Renewable Energy (EERE)
"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...
Supersymmetric quantum mechanics and Painlevé equations
Bermudez, David; Fernández C, David J.
2014-01-08
In these lecture notes we shall study first the supersymmetric quantum mechanics (SUSY QM), specially when applied to the harmonic and radial oscillators. In addition, we will define the polynomial Heisenberg algebras (PHA), and we will study the general systems ruled by them: for zero and first order we obtain the harmonic and radial oscillators, respectively; for second and third order the potential is determined by solutions to Painlevé IV (PIV) and Painlevé V (PV) equations. Taking advantage of this connection, later on we will find solutions to PIV and PV equations expressed in terms of confluent hypergeometric functions. Furthermore, we will classify them into several solution hierarchies, according to the specific special functions they are connected with.
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.
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.
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.
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.
W&M Student Elected to Represent American Physical Society's Graduate
U.S. Department of Energy (DOE) all webpages (Extended Search)
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.
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
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.
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.
Scientists compose complex math equations to replicate behaviors of Earth
U.S. Department of Energy (DOE) all webpages (Extended Search)
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
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.
A multigrid method for variable coefficient Maxwell's equations
Jones, J E; Lee, B
2004-05-13
This paper presents a multigrid method for solving variable coefficient Maxwell's equations. The novelty in this method is the use of interpolation operators that do not produce multilevel commutativity complexes that lead to multilevel exactness. Rather, the effects of multilevel exactness are built into the level equations themselves--on the finest level using a discrete T-V formulation, and on the coarser grids through the Galerkin coarsening procedure of a T-V formulation. These built-in structures permit the levelwise use of an effective hybrid smoother on the curl-free near-nullspace components, and these structures permit the development of interpolation operators for handling the curl-free and divergence-free error components separately, with the resulting block diagonal interpolation operator not satisfying multilevel commutativity but having good approximation properties for both of these error components. Applying operator-dependent interpolation for each of these error components leads to an effective multigrid scheme for variable coefficient Maxwell's equations, where multilevel commutativity-based methods can degrade. Numerical results are presented to verify the effectiveness of this new scheme.
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.
Friedmann's equations in all dimensions and Chebyshev's theorem
Chen, Shouxin; Gibbons, Gary W.; Li, Yijun; Yang, Yisong E-mail: gwg1@damtp.cam.ac.uk E-mail: yisongyang@nyu.edu
2014-12-01
This short but systematic work demonstrates a link between Chebyshev's theorem and the explicit integration in cosmological time t and conformal time η of the Friedmann equations in all dimensions and with an arbitrary cosmological constant Λ. More precisely, it is shown that for spatially flat universes an explicit integration in t may always be carried out, and that, in the non-flat situation and when Λ is zero and the ratio w of the pressure and energy density in the barotropic equation of state of the perfect-fluid universe is rational, an explicit integration may be carried out if and only if the dimension n of space and w obey some specific relations among an infinite family. The situation for explicit integration in η is complementary to that in t. More precisely, it is shown in the flat-universe case with Λ ≠ 0 that an explicit integration in η can be carried out if and only if w and n obey similar relations among a well-defined family which we specify, and that, when Λ = 0, an explicit integration can always be carried out whether the space is flat, closed, or open. We also show that our method may be used to study more realistic cosmological situations when the equation of state is nonlinear.
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.
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
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
Edlund Named DOE Facility Representative of the Year | Y-12 National
U.S. Department of Energy (DOE) all 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
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.
On the vector Helmholtz equation in toroidal waveguides
Biro, Thomas
2005-02-15
A wave splitting method is proposed to solve the problem of propagation of microwaves in a circular waveguide bend of circular cross section. The splitting method, applied to the vector Helmholtz equation, gives a stable solution in terms of waves propagating to the right and to the left in the bend. The formulation is particularly transparent for analyzing the scattering properties of toroidal bends. The basis for the transparency of the method is that the wave splitting is formally exact as the exponential of the square root of a differential operator. The modal functions of the straight cylindrical waveguide are chosen as basis functions in the transverse quasi-toroidal variables.
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.
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.
On the Nonautonomous Nonlinear Schroedinger Equations and Soliton Management
Zhao Dun; Luo Honggang; He Xugang
2010-03-08
We present some novel results on the nonlinear Schroedinger equations with time- and space-dependent dispersion, nonlinearity, dissipation/gain and external potentials which read i(partial derivu(x,t)/partial derivt)+f(x,t)(partial deriv{sup 2}u(x,t)/partial derivx{sup 2})+g(x,t)|u(x,t)|{sup 2}u(x,t)+V(x,t)u(x,t)+igamma (x,t)u(x,t) = 0. Based on these results, we show some explicit ways to control the soliton dynamics in some physically interesting nonlinear systems like Bose-Einstein condensates and optical soliton transmission.
Integral equation for gauge invariant quark Green's function
Sazdjian, H.
2008-08-29
We consider gauge invariant quark two-point Green's functions in which the gluonic phase factor follows a skew-polygonal line. Using a particular representation for the quark propagator in the presence of an external gluon field, functional relations between Green's functions with different numbers of segments of the polygonal lines are established. An integral equation is obtained for the Green's function having a phase factor along a single straight line. The related kernels involve Wilson loops with skew-polygonal contours and with functional derivatives along the sides of the contours.
Vortex equations governing the fractional quantum Hall effect
Medina, Luciano
2015-09-15
An existence theory is established for a coupled non-linear elliptic system, known as “vortex equations,” describing the fractional quantum Hall effect in 2-dimensional double-layered electron systems. Via variational methods, we prove the existence and uniqueness of multiple vortices over a doubly periodic domain and the full plane. In the doubly periodic situation, explicit sufficient and necessary conditions are obtained that relate the size of the domain and the vortex numbers. For the full plane case, existence is established for all finite-energy solutions and exponential decay estimates are proved. Quantization phenomena of the magnetic flux are found in both cases.
Synthesis and equation of state of perovskite in the (Mg,Fe)...
Office of Scientific and Technical Information (OSTI)
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 ...
The Equation of State of LLM-105 (2,6-diamino-3,5-dinitropyrazine...
Office of Scientific and Technical Information (OSTI)
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...
A Novel Hyperbolization Procedure for The Two-Phase Six-Equation...
Office of Scientific and Technical Information (OSTI)
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 ...
Wong's equations and the small x effective action in QCD (Journal...
Office of Scientific and Technical Information (OSTI)
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...
Office of Scientific and Technical Information (OSTI)
A 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...
Office of Scientific and Technical Information (OSTI)
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 ...
Modeling, mesh generation, and adaptive numerical methods for partial differential equations
Babuska, I.; Henshaw, W.D.; Oliger, J.E.; Flaherty, J.E.; Hopcroft, J.E.; Tezduyar, T.
1995-12-31
Mesh generation is one of the most time consuming aspects of computational solutions of problems involving partial differential equations. It is, furthermore, no longer acceptable to compute solutions without proper verification that specified accuracy criteria are being satisfied. Mesh generation must be related to the solution through computable estimates of discretization errors. Thus, an iterative process of alternate mesh and solution generation evolves in an adaptive manner with the end result that the solution is computed to prescribed specifications in an optimal, or at least efficient, manner. While mesh generation and adaptive strategies are becoming available, major computational challenges remain. One, in particular, involves moving boundaries and interfaces, such as free-surface flows and fluid-structure interactions. A 3-week program was held from July 5 to July 23, 1993 with 173 participants and 66 keynote, invited, and contributed presentations. This volume represents written versions of 21 of these lectures. These proceedings are organized roughly in order of their presentation at the workshop. Thus, the initial papers are concerned with geometry and mesh generation and discuss the representation of physical objects and surfaces on a computer and techniques to use this data to generate, principally, unstructured meshes of tetrahedral or hexahedral elements. The remainder of the papers cover adaptive strategies, error estimation, and applications. Several submissions deal with high-order p- and hp-refinement methods where mesh refinement/coarsening (h-refinement) is combined with local variation of method order (p-refinement). Combinations of mathematically verified and physically motivated approaches to error estimation are represented. Applications center on fluid mechanics. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.
DOE Honors WIPP Representative for Cutting Travel Costs, Greenhouse Gas Emissions
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.
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.
Vibrational properties of nanocrystals from the Debye Scattering Equation
Scardi, P.; Gelisio, L.
2016-02-26
One hundred years after the original formulation by Petrus J.W. Debije (aka Peter Debye), the Debye Scattering Equation (DSE) is still the most accurate expression to model the diffraction pattern from nanoparticle systems. A major limitation in the original form of the DSE is that it refers to a static domain, so that including thermal disorder usually requires rescaling the equation by a Debye-Waller thermal factor. The last is taken from the traditional diffraction theory developed in Reciprocal Space (RS), which is opposed to the atomistic paradigm of the DSE, usually referred to as Direct Space (DS) approach. Besides beingmore » a hybrid of DS and RS expressions, rescaling the DSE by the Debye-Waller factor is an approximation which completely misses the contribution of Temperature Diffuse Scattering (TDS). The present work proposes a solution to include thermal effects coherently with the atomistic approach of the DSE. Here, a deeper insight into the vibrational dynamics of nanostructured materials can be obtained with few changes with respect to the standard formulation of the DSE, providing information on the correlated displacement of vibrating atoms.« less
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.
Richards Equation Solver; Rectangular Finite Volume Flux Updating Solution.
Energy Science and Technology Software Center (OSTI)
2002-01-18
Version: 00 POLYRES solves the transient, two-dimensional, Richards equation for water flow in unsaturated-saturated soils. The package is specifically designed to allow the user to easily model complex polygon-shaped regions. Flux, head, and unit gradient boundary conditions can be used. Spatial variation of the hydraulic properties can be defined across individual polygon-shaped subdomains, called objects. These objects combine to form a polygon-shaped model domain. Each object can have its own distribution of hydraulic parameters. Themore » resulting model domain and polygon-shaped internal objects are mapped onto a rectangular, finite-volume, computational grid by a preprocessor. This allows the user to specify model geometry independently of the underlying grid and greatly simplifies user input for complex geometries. In addition, this approach significantly reduces the computational requirements since complex geometries are actually modeled on a rectangular grid. This results in well-structured, finite difference-like systems of equations that require minimal storage and are very efficient to solve.« less
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.
Crystal structure optimisation using an auxiliary equation of state
Jackson, Adam J.; Skelton, Jonathan M.; Hendon, Christopher H.; Butler, Keith T.; Walsh, Aron
2015-11-14
Standard procedures for local crystal-structure optimisation involve numerous energy and force calculations. It is common to calculate an energy–volume curve, fitting an equation of state around the equilibrium cell volume. This is a computationally intensive process, in particular, for low-symmetry crystal structures where each isochoric optimisation involves energy minimisation over many degrees of freedom. Such procedures can be prohibitive for non-local exchange-correlation functionals or other “beyond” density functional theory electronic structure techniques, particularly where analytical gradients are not available. We present a simple approach for efficient optimisation of crystal structures based on a known equation of state. The equilibrium volume can be predicted from one single-point calculation and refined with successive calculations if required. The approach is validated for PbS, PbTe, ZnS, and ZnTe using nine density functionals and applied to the quaternary semiconductor Cu{sub 2}ZnSnS{sub 4} and the magnetic metal-organic framework HKUST-1.
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.
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.
Kumar, Jitendra; Hoffman, Forrest M.; Hargrove, William W.; Collier, Nathan
2016-08-23
Eddy covariance data from regional flux networks are direct in situ measurement of carbon, water, and energy fluxes and are of vital importance for understanding the spatio-temporal dynamics of the the global carbon cycle. FLUXNET links regional networks of eddy covariance sites across the globe to quantify the spatial and temporal variability of fluxes at regional to global scales and to detect emergent ecosystem properties. This study presents an assessment of the representativeness of FLUXNET based on the recently released FLUXNET2015 data set. We present a detailed high resolution analysis of the evolving representativeness of FLUXNET through time. Results providemore » quantitative insights into the extent that various biomes are sampled by the network of networks, the role of the spatial distribution of the sites on the network scale representativeness at any given time, and how that representativeness has changed through time due to changing operational status and data availability at sites in the network. To realize the full potential of FLUXNET observations for understanding emergent ecosystem properties at regional and global scales, we present an approach for upscaling eddy covariance measurements. Informed by the representativeness of observations at the flux sites in the network, the upscaled data reflects the spatio-temporal dynamics of the carbon cycle captured by the in situ measurements. In conclusion, this study presents a method for optimal use of the rich point measurements from FLUXNET to derive an understanding of upscaled carbon fluxes, which can be routinely updated as new data become available, and direct network expansion by identifying regions poorly sampled by the current network.« less
Necessary Conditions for Optimal Control of Stochastic Evolution Equations in Hilbert Spaces
Al-Hussein, Abdul Rahman
2011-06-15
We consider a nonlinear stochastic optimal control problem associated with a stochastic evolution equation. This equation is driven by a continuous martingale in a separable Hilbert space and an unbounded time-dependent linear operator.We derive a stochastic maximum principle for this optimal control problem. Our results are achieved by using the adjoint backward stochastic partial differential equation.
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.
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.
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.
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 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.
Self adaptive methods for parabolic partial differential equations
Gannon, D.B.
1980-08-01
In many applications, the solutions to important partial differential equations are characterized by a sharp active region of transition (such as wave fronts or areas of rapid diffusion) surrounded by relatively calm stable regions. The numerical approximation to such a solution is based on a mesh or grid structure that is best when very fine in the active region and coarse in the calm region. This work considers algorithms for the proper construction of locally refined grids for finite element-based methods for the solution to such problems. Refinement criteria are developed and tested for parabolic problems. The computational complexity of such a strategy is studied, and algorithms based on nested dissection are presented to solve the associated linear algebra problems. 17 figures, 4 tables.
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.
Stochastic Liouville equations for femtosecond stimulated Raman spectroscopy
Agarwalla, Bijay Kumar; Ando, Hideo; Dorfman, Konstantin E.; Mukamel, Shaul
2015-01-14
Electron and vibrational dynamics of molecules are commonly studied by subjecting them to two interactions with a fast actinic pulse that prepares them in a nonstationary state and after a variable delay period T, probing them with a Raman process induced by a combination of a broadband and a narrowband pulse. This technique, known as femtosecond stimulated Raman spectroscopy (FSRS), can effectively probe time resolved vibrational resonances. We show how FSRS signals can be modeled and interpreted using the stochastic Liouville equations (SLE), originally developed for NMR lineshapes. The SLE provide a convenient simulation protocol that can describe complex dynamics caused by coupling to collective bath coordinates at much lower cost than a full dynamical simulation. The origin of the dispersive features that appear when there is no separation of timescales between vibrational variations and the dephasing time is clarified.
Regular perturbation solution of the Elenbaas-Heller equation
Shaw, B.D.
2006-02-01
The Elenbaas-Heller equation is nondimensionalized and solved using regular perturbation theory to provide closed-form analytical solutions to describe structures of cylindrically symmetrical steady electric arc discharges with negligible radiant heat transfer. Based on available data, it is assumed that the electrical conductivity varies with the heat-flux potential in an Arrhenius fashion. The leading-order solution is equivalent to an asymptotic solution proposed by Kuiken [J. Appl. Phys. 58, 1833 (1991)]. Higher-order terms are also derived in the present paper, and it is shown that quantitatively accurate analytical solutions can be developed when higher-order terms are included. Analysis shows that appreciable Joule heating is restricted to an inner zone when a dimensionless parameter is large relative to unity, leading to arc-channel models suggested by previous investigators.
Polynomial solutions of the Monge-Ampère equation
Aminov, Yu A
2014-11-30
The question of the existence of polynomial solutions to the Monge-Ampère 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 a polynomial. It is proved that if f is a polynomial of the second degree, which is positive for all values of its arguments and has a positive squared part, then no polynomial solution exists. On the other hand, a solution 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.
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.
Line Soliton Interactions of the Kadomtsev-Petviashvili Equation
Biondini, Gino
2007-08-10
We study soliton solutions of the Kadomtsev-Petviashvili II equation (-4u{sub t}+6uu{sub x}+3u{sub xxx}){sub x}+u{sub yy}=0 in terms of the amplitudes and directions of the interacting solitons. In particular, we classify elastic N-soliton solutions, namely, solutions for which the number, directions, and amplitudes of the N asymptotic line solitons as y{yields}{infinity} coincide with those of the N asymptotic line solitons as y{yields}-{infinity}. We also show that the (2N-1){exclamation_point}{exclamation_point} types of solutions are uniquely characterized in terms of the individual soliton parameters, and we calculate the soliton position shifts arising from the interactions.
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.
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.
On April 25, 2013, several representatives of energy efficiency advocacy organiz
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
April 25, 2013, several representatives of energy efficiency advocacy organizations met with staff and members of the Compressed Air and Gas Institute (CAGI) along with some compressed air experts at the offices of the Alliance to Save Energy to explore and discuss a consensus approach to advancing energy efficiency of compressed air systems within the context of the DOE's potential rulemaking on compressors. The group discussed the need to assemble the relevant data and technical content that
Chapter 1: Energy Challenges | Representative DOE Energy and Science Program Worshops
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
Energy and Science Program Workshops ENERGY U.S. DEPARTMENT OF Quadrennial Technology Review 2015 1 Quadrennial Technology Review 2015 Representative DOE Energy and Science Program Workshops Chapter 1: Supplemental Information The Quadrennial Technology Review (QTR) found very extensive outreach by the DOE Energy and Science Programs to the broad energy research, development, demonstration, and deployment (RDD&D) community- including industry, academia, civil society, national laboratories,
Identifying representative crop rotation patterns and grassland loss in the US Western Corn Belt
Sahajpal, Ritvik; Zhang, Xuesong; Izaurralde, Roberto C.; Gelfand, Ilya; Hurtt, George C.
2014-10-01
Crop rotations (the practice of growing crops on the same land in sequential seasons) reside at the core of agronomic management as they can influence key ecosystem services such as crop yields, carbon and nutrient cycling, soil erosion, water quality, pest and disease control. Despite the availability of the Cropland Data Layer (CDL) which provides remotely sensed data on crop type in the US on an annual basis, crop rotation patterns remain poorly mapped due to the lack of tools that allow for consistent and efficient analysis of multi-year CDLs. This study presents the Representative Crop Rotations Using Edit Distance (RECRUIT) algorithm, implemented as a Python software package, to select representative crop rotations by combining and analyzing multi-year CDLs. Using CDLs from 2010 to 2012 for 5 states in the US Midwest, we demonstrate the performance and parameter sensitivity of RECRUIT in selecting representative crop rotations that preserve crop area and capture land-use changes. Selecting only 82 representative crop rotations accounted for over 90% of the spatio-temporal variability of the more than 13,000 rotations obtained from combining the multi-year CDLs. Furthermore, the accuracy of the crop rotation product compared favorably with total state-wide planted crop area available from agricultural census data. The RECRUIT derived crop rotation product was used to detect land-use conversion from grassland to crop cultivation in a wetland dominated part of the US Midwest. Monoculture corn and monoculture soybean cropping were found to comprise the dominant land-use on the newly cultivated lands.
WHAT THE SMART GRID MEANS TO YOU AND THE PEOPLE YOU REPRESENT.
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
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
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.
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.
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.
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
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.
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.
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
Accountable Property Representatives/Property Pass Authorization 4/1/2016 Employee Authorized Organization Phone APR Primary Property Pass Signer PETEET, LISA J. ALL ORGS (202) 287-5496 √ AGEE, PATTIE M. EM-40 (202) 586-9417 √ AMES, RUSSELL SC-32 (202) 586-1082 √ √ ANDERSON, SHELLEY EI-11 (202) 586-6196 √ ANDERSON, SUE EM-73 (301) 903-8368 √ √ ATKINSON-HYMAN, DEBRA PA-1 (202) 586-2461 √ √ AUGUSTYN, ANN HG-6 (202) 287-1528 √ BARLETT, DENNIS EE-3C (202) 586-0874 √ BARNES,
A general encoding framework for representing network measurement and topology data
U.S. Department of Energy (DOE) all webpages (Extended Search)
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,
Dooley, James J.; Calvin, Katherine V.
2011-04-18
The Intergovernmental Panel on Climate Change’s (IPCC) Fifth Assessment (to be published in 2013-2014) will to a significant degree be built around four Representative Concentration Pathways (RCPs) that are intended to represent four scenarios of future development of greenhouse gas emissions, land use, and concentrations that span the widest range of potential future atmospheric radiative forcing. Under the very stringent climate policy implied by the 2.6 W/m2 overshoot scenario, all electricity is eventually generated from low carbon sources. However, carbon dioxide capture and storage (CCS) technologies never comprise more than 50% of total electricity generation in that very stringent scenario or in any of the other cases examined here. There are significant differences among the cases studied here in terms of how CCS technologies are used, with the most prominent being is the significant expansion of biomass+CCS as the stringency of the implied climate policy increases. Cumulative CO2 storage across the three cases that imply binding greenhouse gas constraints ranges by nearly an order of magnitude from 170GtCO2 (radiative forcing of 6.0W/m2 in 2100) to 1600GtCO2 (2.6W/m2 in 2100) over the course of this century. This potential demand for deep geologic CO2 storage is well within published estimates of total global CO2 storage capacity.
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.
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.
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.}
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.
Concerning the equation of state for partially ionized system
Baker, Jr, George A
2008-01-01
I will discuss the expansion of various thermodynamic quantities about the ideal gas in powers of the electric charge, and I will discuss some cellular models. The first type of cellular model is appropriate for hydrogen. The second type is for Z > 1. It has the independent electron approximation within the atoms. These models are cross compared and minimal regions of validity are determined. The actual region of validity is expected to be larger. In the cellular models, the phase boundaries for liquid-gas transitions are found. For the second type of cellular model, in the part of the low-temperature, low-density region where there is not much expectation of validity of these methods, a non-thermodynamic region is found. I have devised a construction, similar in spirit to the Maxwell construction, to bridge this region so as to leave a thermodynamically valid equation of state. The non-thermodynamic region does not occur in hydrogen and it seems to be due to the inadequacy of the aforementioned approximation in that region.
A Schamel equation for ion acoustic waves in superthermal plasmas
Williams, G. Kourakis, I.; Verheest, F.; Hellberg, M. A.; Anowar, M. G. M.
2014-09-15
An investigation of the propagation of ion acoustic waves in nonthermal plasmas in the presence of trapped electrons has been undertaken. This has been motivated by space and laboratory plasma observations of plasmas containing energetic particles, resulting in long-tailed distributions, in combination with trapped particles, whereby some of the plasma particles are confined to a finite region of phase space. An unmagnetized collisionless electron-ion plasma is considered, featuring a non-Maxwellian-trapped electron distribution, which is modelled by a kappa distribution function combined with a Schamel distribution. The effect of particle trapping has been considered, resulting in an expression for the electron density. Reductive perturbation theory has been used to construct a KdV-like Schamel equation, and examine its behaviour. The relevant configurational parameters in our study include the superthermality index κ and the characteristic trapping parameter β. A pulse-shaped family of solutions is proposed, also depending on the weak soliton speed increment u{sub 0}. The main modification due to an increase in particle trapping is an increase in the amplitude of solitary waves, yet leaving their spatial width practically unaffected. With enhanced superthermality, there is a decrease in both amplitude and width of solitary waves, for any given values of the trapping parameter and of the incremental soliton speed. Only positive polarity excitations were observed in our parametric investigation.
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).
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)
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.
Solving the power flow equations: a monotone operator approach
Dvijotham, Krishnamurthy; Low, Steven; Chertkov, Michael
2015-07-21
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. These methods work well given a good initial “guess” for the solution, which is always available in normal system operations. However, with the increase in levels of intermittent generation, the assumption of a good initial guess always being available is no longer valid. In this paper, we solve this problem using the theory of monotone operators. We show that it is possible to compute (using an offline optimization) a “monotonicity domain” in the space of voltage phasors. Given this domain, there is a simple efficient algorithm that will either find a solution in the domain, or provably certify that no solutions exist in it. We validate the approach on several IEEE test cases and demonstrate that the offline optimization can be performed tractably and the computed “monotonicity domain” includes all practically relevant power flow solutions.
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.
An Asymptotic Study of Discretized Transport Equations in the Fokker-Planck Limit
Pautz, Shawn D.; Adams, Marvin L.
2002-01-15
Recent analyses have shown that the Fokker-Planck equation is an asymptotic limit of the transport equation given a forward-peaked scattering kernel satisfying certain constraints. Discretized transport equations in the same limit are studied, both by asymptotic analysis and by numerical testing. It is shown that spatially discretized discrete ordinates transport solutions can be accurate in this limit if and only if the scattering operator is handled in a certain nonstandard way.
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.
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.
A global solution to the Schrödinger equation: From Henstock to Feynman
Nathanson, Ekaterina S.; Jørgensen, Palle E. T.
2015-09-15
One of the key elements of Feynman’s formulation of non-relativistic quantum mechanics is a so-called Feynman path integral. It plays an important role in the theory, but it appears as a postulate based on intuition, rather than a well-defined object. All previous attempts to supply Feynman’s theory with rigorous mathematics underpinning, based on the physical requirements, have not been satisfactory. The difficulty comes from the need to define a measure on the infinite dimensional space of paths and to create an integral that would possess all of the properties requested by Feynman. In the present paper, we consider a new approach to defining the Feynman path integral, based on the theory developed by Muldowney [A Modern Theory of Random Variable: With Applications in Stochastic Calcolus, Financial Mathematics, and Feynman Integration (John Wiley & Sons, Inc., New Jersey, 2012)]. Muldowney uses the Henstock integration technique and deals with non-absolute integrability of the Fresnel integrals, in order to obtain a representation of the Feynman path integral as a functional. This approach offers a mathematically rigorous definition supporting Feynman’s intuitive derivations. But in his work, Muldowney gives only local in space-time solutions. A physical solution to the non-relativistic Schrödinger equation must be global, and it must be given in the form of a unitary one-parameter group in L{sup 2}(ℝ{sup n}). The purpose of this paper is to show that a system of one-dimensional local Muldowney’s solutions may be extended to yield a global solution. Moreover, the global extension can be represented by a unitary one-parameter group acting in L{sup 2}(ℝ{sup n})
Equation of state of pyrite to 80 GPa and 2400 K (Journal Article...
Office of Scientific and Technical Information (OSTI)
Title: Equation of state of pyrite to 80 GPa and 2400 K Authors: Thompson, Elizabeth C. ; Chidester, Bethany A. ; Fischer, Rebecca A. ; Myers, Gregory I. ; Heinz, Dion L. ; ...
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.
The thermal equation of state of (Mg, Fe)SiO[subscript 3] bridgmanite...
Office of Scientific and Technical Information (OSTI)
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 ...
The (1+1)-D Duffin-Kemmer-Petiau Equation In A Constant Gravitational Field
Havare, A. Kemal; Havare, Ali; Soeguet, Kenan
2007-04-23
In curved space-time, in order to understand how curved space-time affects the dynamics of scalar and spinning particles, we solve the relativistic particles equations in curved space-time. In the present paper our intention is to solve the (1+1) D Duffin-Kemmer-Petiau (DKP) equation in the background metric ds2=u2(x) (-dt2+dx2). The resulting equation is studied for the special case u(x) = 1 + gx. Finally we discuss the result by comparing with solutions of the Klein-Gordon and the Dirac equations in the presence of background the same metric.
Validity of equation-of-motion approach to kondo problem in the...
Office of Scientific and Technical Information (OSTI)
Visit OSTI to utilize additional information resources in energy science and technology. A ... equation for the one-particle Green function is derived and numerically solved ...
Validity of equation-of-motion approach to kondo problem in the large N
Office of Scientific and Technical Information (OSTI)
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 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 self-consistent equation for the one-particle
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.
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
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.
Two Soliton Interactions of BD.I Multicomponent NLS Equations and Their Gauge Equivalent
Gerdjikov, V. S.; Grahovski, G. G.
2010-11-25
Using the dressing Zakharov-Shabat method we re-derive the effects of the two-soliton interactions for the MNLS equations related to the BD.I-type symmetric spaces. Next we generalize this analysis for the Heisenberg ferromagnet type equations, gauge equivalent to MNLS.
Chou, Chia-Chun
2014-03-14
The complex quantum Hamilton-Jacobi equation-Bohmian trajectories (CQHJE-BT) method is introduced as a synthetic trajectory method for integrating the complex quantum Hamilton-Jacobi equation for the complex action function by propagating an ensemble of real-valued correlated Bohmian trajectories. Substituting the wave function expressed in exponential form in terms of the complex action into the time-dependent Schrödinger equation yields the complex quantum Hamilton-Jacobi equation. We transform this equation into the arbitrary Lagrangian-Eulerian version with the grid velocity matching the flow velocity of the probability fluid. The resulting equation describing the rate of change in the complex action transported along Bohmian trajectories is simultaneously integrated with the guidance equation for Bohmian trajectories, and the time-dependent wave function is readily synthesized. The spatial derivatives of the complex action required for the integration scheme are obtained by solving one moving least squares matrix equation. In addition, the method is applied to the photodissociation of NOCl. The photodissociation dynamics of NOCl can be accurately described by propagating a small ensemble of trajectories. This study demonstrates that the CQHJE-BT method combines the considerable advantages of both the real and the complex quantum trajectory methods previously developed for wave packet dynamics.
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.
Approximating electronically excited states with equation-of-motion linear coupled-cluster theory
Byrd, Jason N. Rishi, Varun; Perera, Ajith; Bartlett, Rodney J.
2015-10-28
A new perturbative approach to canonical equation-of-motion coupled-cluster theory is presented using coupled-cluster perturbation theory. A second-order Møller-Plesset partitioning of the Hamiltonian is used to obtain the well known equation-of-motion many-body perturbation theory equations and two new equation-of-motion methods based on the linear coupled-cluster doubles and linear coupled-cluster singles and doubles wavefunctions. These new methods are benchmarked against very accurate theoretical and experimental spectra from 25 small organic molecules. It is found that the proposed methods have excellent agreement with canonical equation-of-motion coupled-cluster singles and doubles state for state orderings and relative excited state energies as well as acceptable quantitative agreement for absolute excitation energies compared with the best estimate theory and experimental spectra.
Horowitz, Jordan M.
2015-07-28
The stochastic thermodynamics of a dilute, well-stirred mixture of chemically reacting species is built on the stochastic trajectories of reaction events obtained from the chemical master equation. However, when the molecular populations are large, the discrete chemical master equation can be approximated with a continuous diffusion process, like the chemical Langevin equation or low noise approximation. In this paper, we investigate to what extent these diffusion approximations inherit the stochastic thermodynamics of the chemical master equation. We find that a stochastic-thermodynamic description is only valid at a detailed-balanced, equilibrium steady state. Away from equilibrium, where there is no consistent stochastic thermodynamics, we show that one can still use the diffusive solutions to approximate the underlying thermodynamics of the chemical master equation.
Generalization of the Kohn-Sham system that can represent arbitrary one-electron density matrices
Hubertus J. J. van Dam
2016-05-23
Density functional theory is currently the most widely applied method in electronic structure theory. The Kohn-Sham method, based on a fictitious system of noninteracting particles, is the workhorse of the theory. The particular form of the Kohn-Sham wave function admits only idempotent one-electron density matrices whereas wave functions of correlated electrons in post-Hartree-Fock methods invariably have fractional occupation numbers. Here we show that by generalizing the orbital concept and introducing a suitable dot product as well as a probability density, a noninteracting system can be chosen that can represent the one-electron density matrix of any system, even one with fractionalmore » occupation numbers. This fictitious system ensures that the exact electron density is accessible within density functional theory. It can also serve as the basis for reduced density matrix functional theory. Moreover, to aid the analysis of the results the orbitals may be assigned energies from a mean-field Hamiltonian. This produces energy levels that are akin to Hartree-Fock orbital energies such that conventional analyses based on Koopmans' theorem are available. Lastly, this system is convenient in formalisms that depend on creation and annihilation operators as they are trivially applied to single-determinant wave functions.« less
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.
Dalgicdir, Cahit; Sensoy, Ozge; Sayar, Mehmet; Peter, Christine
2013-12-21
One of the major challenges in the development of coarse grained (CG) simulation models that aim at biomolecular structure formation processes is the correct representation of an environment-driven conformational change, for example, a folding/unfolding event upon interaction with an interface or upon aggregation. In the present study, we investigate this transferability challenge for a CG model using the example of diphenylalanine. This dipeptide displays a transition from a trans-like to a cis-like conformation upon aggregation as well as upon transfer from bulk water to the cyclohexane/water interface. Here, we show that one can construct a single CG model that can reproduce both the bulk and interface conformational behavior and the segregation between hydrophobic/hydrophilic medium. While the general strategy to obtain nonbonded interactions in the present CG model is to reproduce solvation free energies of small molecules representing the CG beads in the respective solvents, the success of the model strongly depends on nontrivial decisions one has to make to capture the delicate balance between the bonded and nonbonded interactions. In particular, we found that the peptide's conformational behavior is qualitatively affected by the cyclohexane/water interaction potential, an interaction that does not directly involve the peptide at all but merely influences the properties of the hydrophobic/hydrophilic interface. Furthermore, we show that a small modification to improve the structural/conformational properties of the CG model could dramatically alter the thermodynamic properties.
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.
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.
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
Extraction of organic compounds from representative shales and the effect on porosity
DiStefano, Victoria H.; McFarlane, Joanna; Anovitz, Lawrence M.; Stack, Andrew G.; Gordon, Alexander D.; Littrell, Ken C.; Chipera, Steve J.; Hunt, Rodney D.; Lewis, Samuel A.; Hale, Richard E.; et al
2016-09-01
This study is an attempt to understand how native organics are distributed with respect to pore size to determine the relationship between hydrocarbon chemistry and pore structure in shales, as the location and accessibility of hydrocarbons is key to understanding and improving the extractability of hydrocarbons in hydraulic fracturing. Selected shale cores from the Eagle Ford and Marcellus formations were subjected to pyrolysis gas chromatography (GC), thermogravimetric analysis, and organic solvent extraction with the resulting effluent analyzed by GC-mass spectrometry (MS). Organics representing the oil and gas fraction (0.1 to 1 wt. %) were observed by GC-MS. For most ofmore » the samples, the amount of native organic extracted directly related to the percentage of clay in the shale. The porosity and pore size distribution (0.95 nm to 1.35 m) in the Eagle Ford and Marcellus shales was measured before and after solvent extraction using small angle neutron scattering (SANS). An unconventional method was used to quantify the background from incoherent scattering as the Porod transformation obscures the Bragg peak from the clay minerals. Furthermore, the change in porosity from SANS is indicative of the extraction or breakdown of higher molecular weight bitumen with high C/H ratios (asphaltenes and resins). This is mostly likely attributed to complete dissolution or migration of asphaltenes and resins. These longer carbon chain lengths, C30-C40, were observed by pyrolysis GC, but either were too heavy to be analyzed in the extracts by GC-MS or were not effectively leached into the organic solvents. Thus, experimental limitations meant that the amount of extractable material could not be directly correlated to the changes in porosity measured by SANS. But, the observable porosity generally increased with solvent extraction. A decrease in porosity after extraction as observed in a shale with high clay content and low maturity was attributed to swelling of pores
Representing northern peatland microtopography and hydrology within the Community Land Model
Shi, Xiaoying; Thornton, Peter E.; Ricciuto, Daniel M.; Hanson, Paul J.; Mao, Jiafu; Sebestyen, Stephen D.; Griffiths, Natalie A.; Bisht, Gautam
2015-11-12
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 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. Furthermore, the new model provides improved predictive capacity for seasonal hydrological dynamics
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.
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.
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)
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.
Equations of state and stability of MgSiO3 perovskite and post-perovskite
Office of Scientific and Technical Information (OSTI)
phases from quantum Monte Carlo simulations (Journal Article) | SciTech Connect Equations of state and stability of MgSiO3 perovskite and post-perovskite phases from quantum Monte Carlo simulations Citation Details In-Document Search Title: Equations of state and stability of MgSiO3 perovskite and post-perovskite phases from quantum Monte Carlo simulations In this study, we have performed quantum Monte Carlo (QMC) simulations and density functional theory calculations to study the equations
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.
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
New Improved Equations For Na-K, Na-Li And Sio2 Geothermometers...
Open Energy Information (Open El) [EERE & EIA]
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:...
Thermal equation of state and stability of (Mg[subscript 0.06...
Office of Scientific and Technical Information (OSTI)
SciTech Connect Search Results Journal Article: Thermal equation of state and stability of (Mgsubscript 0.06Fesubscript 0.94)O Citation Details In-Document Search Title: ...
Electrolux Gibson Air Conditioner and Equator Clothes Washer Fail DOE Energy Star Testing
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...
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.
Equation of state and phase diagram of Fe-16Si alloy as a candidate...
Office of Scientific and Technical Information (OSTI)
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 ...
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.
Equations of state in the Fe-FeSi system at high pressures and...
Office of Scientific and Technical Information (OSTI)
SciTech Connect Search Results Journal Article: Equations of state in the Fe-FeSi system ... Country of Publication: United States Language: ENGLISH Word Cloud More Like This Full ...
Evolution of higher order nonlinear equation for the dust ion-acoustic waves in nonextensive plasma
Yasmin, S.; Asaduzzaman, M.; Mamun, A. A.
2012-10-15
There are three different types of nonlinear equations, namely, Korteweg-de Vries (K-dV), modified K-dV (mK-dV), and mixed modified K-dV (mixed mK-dV) equations, for the nonlinear propagation of the dust ion-acoustic (DIA) waves. The effects of electron nonextensivity on DIA solitary waves propagating in a dusty plasma (containing negatively charged stationary dust, inertial ions, and nonextensive q distributed electrons) are examined by solving these nonlinear equations. The basic features of mixed mK-dV (higher order nonlinear equation) solitons are found to exist beyond the K-dV limit. The properties of mK-dV solitons are compared with those of mixed mK-dV solitons. It is found that both positive and negative solitons are obtained depending on the q (nonextensive parameter).
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.
A UQ Enabled Aluminum Tabular Multiphase Equation-of-State Model
Office of Scientific and Technical Information (OSTI)
1325C A UQ Enabled Aluminum Tabular Multiphase Equation-of-State Model Allen C. Robinson, John H. Carpenter0, Bert J. Debusschere*, Ann E. Mattsson0 t Computational Multiphysics, ...
First-principles high-pressure unreacted equation of state and...
Office of Scientific and Technical Information (OSTI)
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 ...
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.
Thermal equation of state and stability of (Mg0.06Fe0.94)O (Journal...
Office of Scientific and Technical Information (OSTI)
Thermal equation of state and stability of (Mg0.06Fe0.94)O This content will become publicly available on November 8, 2017 Title: Thermal equation of state and stability of ...
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.
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 solutions of the Fokker-Planck equations with moving boundaries
Lo, C.F. . E-mail: cflo@phy.cuhk.edu.hk
2005-10-01
By means of time-dependent similarity transformations, we derive exact solutions of the Fokker-Planck equations with moving boundaries in the presence of: (1) a time-dependent linear force and (2) a time-dependent nonlinear force. The method of similarity transformation is simple and can be easily applied to more general Fokker-Planck equations. Furthermore, the knowledge of the exact solutions in closed form can be useful as a benchmark to test approximate numerical or analytical procedures.
Fokker-Planck equations and density of states in disordered quantum wires
Titov, M.; Brouwer, P. W.; Furusaki, A.; Mudry, C.
2001-06-15
We propose a general scheme to construct scaling equations for the density of states in disordered quantum wires for all ten pure Cartan symmetry classes. The anomalous behavior of the density of states near the Fermi level {var_epsilon}=0 for the three chiral and four Bogoliubov{endash}de Gennes universality classes is analyzed in detail by means of a mapping to a scaling equation for the reflection from a quantum wire in the presence of an imaginary potential.
Mikami, T.
2000-07-01
R. Jordan, D. Kinderlehrer, and F. Otto proposed the discrete-time approximation of the Fokker-Planck equation by the variational formulation. It is determined by the Wasserstein metric, an energy functional, and the Gibbs-Boltzmann entropy functional. In this paper we study the asymptotic behavior of the dynamical systems which describe their approximation of the Fokker-Planck equation and characterize the limit as a solution to a class of variational problems.
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.
Solutions of Boltzmann`s Equation for Mono-energetic Neutrons in an Infinite Homogeneous Medium
DOE R&D Accomplishments [OSTI]
Wigner, E. P.
1943-11-30
Boltzman's equation is solved for the case of monoenergetic neutrons created by a plane or point source in an infinite medium which has spherically symmetric scattering. The customary solution of the diffusion equation appears to be multiplied by a constant factor which is smaller than 1. In addition to this term the total neutron density contains another term which is important in the neighborhood of the source. It varies as 1/r{sup 2} in the neighborhood of a point source. (auth)
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.
Equations Governing Space-Time Variability of Liquid Water Path in Stratus Clouds
U.S. Department of Energy (DOE) all webpages (Extended Search)
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
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.
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.
Jaeger, J.
1983-07-14
Correcting the dispersion function in the SLC north arc it turned out that backleg-windings (BLW) acting horizontally as well as BLW acting vertically have to be used. In the latter case the question arose what is the best representation of a defocusing magnet with excited BLW acting in the vertical plane for the computer code TURTLE. Two different schemes, the 14.-scheme and the 20.-scheme were studied and the TURTLE output for one ray through such a magnet compared with the numerical solution of the equation of motion; only terms of first order have been taken into account.
Mukherjee, Abhik Janaki, M. S. Kundu, Anjan
2015-07-15
A new, completely integrable, two dimensional evolution equation is derived for an ion acoustic wave propagating in a magnetized, collisionless plasma. The equation is a multidimensional generalization of a modulated wavepacket with weak transverse propagation, which has resemblance to nonlinear Schrödinger (NLS) equation and has a connection to Kadomtsev-Petviashvili equation through a constraint relation. Higher soliton solutions of the equation are derived through Hirota bilinearization procedure, and an exact lump solution is calculated exhibiting 2D structure. Some mathematical properties demonstrating the completely integrable nature of this equation are described. Modulational instability using nonlinear frequency correction is derived, and the corresponding growth rate is calculated, which shows the directional asymmetry of the system. The discovery of this novel (2+1) dimensional integrable NLS type equation for a magnetized plasma should pave a new direction of research in the field.
Dynamics of the Zakharov-Kuznetsov-Burgers equations in dusty plasmas
Zhen, Hui-Ling; Tian, Bo; Zhong, Hui; Sun, Wen-Rong; Li, Min
2013-08-15
In this paper, we investigate the Zakharov-Kuznetsov-Burgers (ZKB) equations for the dust-ion-acoustic waves in dusty plasmas. Shock-like and soliton solutions are both constructed through the introduction of an auxiliary function and variable. ZKB-soliton propagation is plotted, and from those figures, we find that energy of the solitons increases when the number of electrons in a dust particle decreases or the mass of such dust particle becomes larger. Considering the external perturbations in the dusty plasmas, we study the perturbed ZKB equation via some qualitative and quantitative methods. To corroborate that the perturbed ZKB equation can indeed give rise to the chaos, we make use of the power spectrum and Lyapunov exponents. Then, we investigate the phase projections, and find that both the weak and developed chaos can be observed. Weak chaos occur when the absolute value of damped coefficient (l{sub 1}) is stronger than the strength of perturbed term (g{sub 1}), or else, the developed one occurs. Ranges of l{sub 1} and g{sub 1} are given via the largest Lyapunov exponents when the perturbed ZKB equation is in different chaotic states. Therefore, we can find that the chaotic motion of the perturbed ZKB equation will be enhanced with the number of electrons in a dust particle or the mass of such a dust particle decreasing.
Solitary waves in the nonlinear Dirac equation in the presence of external driving forces
Mertens, Franz G.; Cooper, Fred; Quintero, Niurka R.; Shao, Sihong; Khare, Avinash; Saxena, Avadh
2016-01-05
In this paper, we consider the nonlinear Dirac (NLD) equation in (1 + 1) dimensions with scalar–scalar self interaction g2/κ + 1 (Ψ¯Ψ)κ + 1 in the presence of external forces as well as damping of the form f(x) - iμγ0Ψ, where both f and Ψ are two-component spinors. We develop an approximate variational approach using collective coordinates (CC) for studying the time dependent response of the solitary waves to these external forces. This approach predicts intrinsic oscillations of the solitary waves, i.e. the amplitude, width and phase all oscillate with the same frequency. The translational motion is also affected,more » because the soliton position oscillates around a mean trajectory. For κ = 1 we solve explicitly the CC equations of the variational approximation for slow moving solitary waves in a constant external force without damping and find reasonable agreement with solving numerically the CC equations. Finally, we then compare the results of the variational approximation with no damping with numerical simulations of the NLD equation for κ = 1, when the components of the external force are of the form fj = rj exp(–iΚx) and again find agreement if we take into account a certain linear excitation with specific wavenumber that is excited together with the intrinsic oscillations such that the momentum in a transformed NLD equation is conserved.« less
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.
Zhang, D.S.; Wei, G.W.; Kouri, D.J.; Hoffman, D.K.
1997-03-01
The distributed approximating functional method is applied to the solution of the Fokker{endash}Planck equations. The present approach is limited to the standard eigenfunction expansion method. Three typical examples, a Lorentz Fokker{endash}Planck equation, a bistable diffusion model and a Henon{endash}Heiles two-dimensional anharmonic resonating system, are considered in the present numerical testing. All results are in excellent agreement with those of established methods in the field. It is found that the distributed approximating functional method yields the accuracy of a spectral method but with a local method{close_quote}s simplicity and flexibility for the eigenvalue problems arising from the Fokker{endash}Planck equations. {copyright} {ital 1997 American Institute of Physics.}
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.
An implicit fast Fourier transform method for integration of the time dependent Schrodinger equation
Riley, M.E.; Ritchie, A.B.
1997-12-31
One finds that the conventional exponentiated split operator procedure is subject to difficulties when solving the time-dependent Schrodinger equation for Coulombic systems. By rearranging the kinetic and potential energy terms in the temporal propagator of the finite difference equations, one can find a propagation algorithm for three dimensions that looks much like the Crank-Nicholson and alternating direction implicit methods for one- and two-space-dimensional partial differential equations. The authors report investigations of this novel implicit split operator procedure. The results look promising for a purely numerical approach to certain electron quantum mechanical problems. A charge exchange calculation is presented as an example of the power of the method.
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.
Parallel FE Approximation of the Even/Odd Parity Form of the Linear Boltzmann Equation
Drumm, Clifton R.; Lorenz, Jens
1999-07-21
A novel solution method has been developed to solve the linear Boltzmann equation on an unstructured triangular mesh. Instead of tackling the first-order form of the equation, this approach is based on the even/odd-parity form in conjunction with the conventional mdtigroup discrete-ordinates approximation. The finite element method is used to treat the spatial dependence. The solution method is unique in that the space-direction dependence is solved simultaneously, eliminating the need for the conventional inner iterations, and the method is well suited for massively parallel computers.
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.
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,
Cave, J.R.; Evetts, J.E.
1986-04-01
A modified form of London's equation describing the penetration of magnetic flux into an inhomogeneous superconductor is derived from the Ginzburg-Landau theory. This equation takes into account spatial variation of the magnetic penetration depth. The magnetic flux penetration into an inhomogeneous superconducting slab is calculated and a method is described whereby the spatial variation of the critical temperature can be obtained from an inductive T/sub c/ transition. The consequences of using other sample geometries and the relevance of this work to the characterization of practical superconducting wires is discussed.
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.
Liang, Xiao; Khaliq, Abdul Q. M.; Xing, Yulong
2015-01-23
In this paper, we study a local discontinuous Galerkin method combined with fourth order exponential time differencing Runge-Kutta time discretization and a fourth order conservative method for solving the nonlinear Schrödinger equations. Based on different choices of numerical fluxes, we propose both energy-conserving and energy-dissipative local discontinuous Galerkin methods, and have proven the error estimates for the semi-discrete methods applied to linear Schrödinger equation. The numerical methods are proven to be highly efficient and stable for long-range soliton computations. Finally, extensive numerical examples are provided to illustrate the accuracy, efficiency and reliability of the proposed methods.
Constraining the equation of state of superhadronic matter from heavy-ion collisions
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.
Soliton solutions of the 3D Gross-Pitaevskii equation by a potential control method
Fedele, R.; Eliasson, B.; Shukla, P. K.; Haas, F.; Jovanovic, D.; De Nicola, S.
2010-12-14
We present a class of three-dimensional solitary waves solutions of the Gross-Pitaevskii (GP) equation, which governs the dynamics of Bose-Einstein condensates (BECs). By imposing an external controlling potential, a desired time-dependent shape of the localized BEC excitation is obtained. The stability of some obtained localized solutions is checked by solving the time-dependent GP equation numerically with analytic solutions as initial conditions. The analytic solutions can be used to design external potentials to control the localized BECs in experiment.
Temperature-dependent isovector pairing gap equations using a path integral approach
Fellah, M.; Allal, N. H.; Belabbas, M.; Oudih, M. R.; Benhamouda, N.
2007-10-15
Temperature-dependent isovector neutron-proton (np) pairing gap equations have been established by means of the path integral approach. These equations generalize the BCS ones for the pairing between like particles at finite temperature. The method has been numerically tested using the one-level model. It has been shown that the gap parameter {delta}{sub np} has a behavior analogous to that of {delta}{sub nn} and {delta}{sub pp} as a function of the temperature: one notes the presence of a critical temperature. Moreover, it has been shown that the isovector pairing effects remain beyond the critical temperature that corresponds to the pairing between like particles.
Vanvincq, O.; Travers, J. C.; Kudlinski, A.
2011-12-15
We reexamine the derivation of the generalized nonlinear Schroedinger equation in the case of nonaxially uniform optical fibers, taking into account the longitudinal and spectral evolutions of all pertinent linear parameters. Our theory leads to an improved form of this equation that highlights an additional term, which ensures the conservation of the total photon number in nonuniform optical fibers in the absence of attenuation. Numerical simulations confirm the validity of this theory in the context of a Raman-induced soliton self-frequency shift, emission of Cherenkov radiation, and a soliton blue shift.
Solving the transport equation with quadratic finite elements: Theory and applications
Ferguson, J.M.
1997-12-31
At the 4th Joint Conference on Computational Mathematics, the author presented a paper introducing a new quadratic finite element scheme (QFEM) for solving the transport equation. In the ensuing year the author has obtained considerable experience in the application of this method, including solution of eigenvalue problems, transmission problems, and solution of the adjoint form of the equation as well as the usual forward solution. He will present detailed results, and will also discuss other refinements of his transport codes, particularly for 3-dimensional problems on rectilinear and non-rectilinear grids.
Construction Control Representative
(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)
Fast non-symmetric iterations and efficient preconditioning for Navier-Stokes equations
Silvester, D.; Elman, H.
1994-12-31
Discretisation of the steady-state Navier-Stokes equations: (u.grad)u-{nu}{del}{sup 2}u + grad p = 0; div u = 0 [1]. in some flow domain {Omega} {contained_in} IR{sup d}, (d = 2 or 3), gives a system of non-linear algebraic equations for discretised variables u (the velocity), and p (the pressure). The authors assume that appropriate boundary conditions are imposed. The non-linear equation system can be linearised using a fixed-point (Picard) iteration to give a matrix system which must be solved at every iteration. Part of this matrix is block diagonal, and consists of d convection-diffusion operators, one for each component of velocity. Two difficulties arise when solving this matrix equation. Firstly, the block diagonal part is not symmetric, although under certain conditions the symmetric part is positive definite. Secondly, the overall system is indefinite. This makes the design of fast and efficient iterative solvers for discretised Navier-Stokes operators an extremely challenging task.
Basermann, A.
1994-12-31
For the solution of discretized ordinary or partial differential equations it is necessary to solve systems of equations or eigenproblems with coefficient matrices of different sparsity pattern, depending on the discretization method; using the finite element method (FE) results in largely unstructured systems of equations. Sparse eigenproblems play particularly important roles in the analysis of elastic solids and structures. In the corresponding FE models, the natural frequencies and mode shapes of free vibration are determined as are buckling loads and modes. Another class of problems is related to stability analysis, e.g. of electrical networks. Moreover, approximations of extreme eigenvalues are useful for solving sets of linear equations, e.g. for determining condition numbers of symmetric positive definite matrices or for conjugate gradients methods with polynomial preconditioning. Iterative methods for solving linear systems and eigenproblems mainly consist of matrix-vector products and vector-vector operations; the main work in each iteration is usually the computation of matrix-vector products. Therein, accessing the vector is determined by the sparsity pattern and the storage scheme of the matrix.
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.
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.
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.
The precise time-dependent solution of the Fokker–Planck equation with anomalous diffusion
Guo, Ran; Du, Jiulin
2015-08-15
We study the time behavior of the Fokker–Planck equation in Zwanzig’s rule (the backward-Ito’s rule) based on the Langevin equation of Brownian motion with an anomalous diffusion in a complex medium. The diffusion coefficient is a function in momentum space and follows a generalized fluctuation–dissipation relation. We obtain the precise time-dependent analytical solution of the Fokker–Planck equation and at long time the solution approaches to a stationary power-law distribution in nonextensive statistics. As a test, numerically we have demonstrated the accuracy and validity of the time-dependent solution. - Highlights: • The precise time-dependent solution of the Fokker–Planck equation with anomalous diffusion is found. • The anomalous diffusion satisfies a generalized fluctuation–dissipation relation. • At long time the time-dependent solution approaches to a power-law distribution in nonextensive statistics. • Numerically we have demonstrated the accuracy and validity of the time-dependent solution.
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.
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.
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.
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.
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.
Nonlinear quantum-mechanical system associated with Sine-Gordon equation in (1 + 2) dimensions
Zarmi, Yair
2014-10-15
Despite the fact that it is not integrable, the (1 + 2)-dimensional Sine-Gordon equation has N-soliton solutions, whose velocities are lower than the speed of light (c = 1), for all N ≥ 1. Based on these solutions, a quantum-mechanical system is constructed over a Fock space of particles. The coordinate of each particle is an angle around the unit circle. U, a nonlinear functional of the particle number-operators, which obeys the Sine-Gordon equation in (1 + 2) dimensions, is constructed. Its eigenvalues on N-particle states in the Fock space are the slower-than-light, N-soliton solutions of the equation. A projection operator (a nonlinear functional of U), which vanishes on the single-particle subspace, is a mass-density generator. Its eigenvalues on multi-particle states play the role of the mass density of structures that emulate free, spatially extended, relativistic particles. The simplicity of the quantum-mechanical system allows for the incorporation of perturbations with particle interactions, which have the capacity to “annihilate” and “create” solitons – an effect that does not have an analog in perturbed classical nonlinear evolution equations.
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.
Kadanoff-Baym equations with non-Gaussian initial conditions: The equilibrium limit
Garny, Mathias; Mueller, Markus Michael
2009-10-15
The nonequilibrium dynamics of quantum fields is an initial-value problem, which can be described by Kadanoff-Baym equations. Typically, and, in particular, when numerical solutions are demanded, these Kadanoff-Baym equations are restricted to Gaussian initial states. However, physical initial states are non-Gaussian correlated initial states. In particular, renormalizability requires the initial state to feature n-point correlations that asymptotically agree with the vacuum correlations at short distances. In order to identify physical nonequilibrium initial states, it is therefore a precondition to describe the vacuum correlations of the interacting theory within the nonequilibrium framework. In this paper, Kadanoff-Baym equations for non-Gaussian correlated initial states describing vacuum and thermal equilibrium are derived from the 2PI effective action. A diagrammatic method for the explicit construction of vacuum and thermal initial correlations from the 2PI effective action is provided. We present numerical solutions of Kadanoff-Baym equations for a real scalar {phi}{sup 4} quantum field theory, which take the thermal initial four-point correlation as the leading non-Gaussian correction into account. We find that this minimal non-Gaussian initial condition yields an approximation to the complete equilibrium initial state that is quantitatively and qualitatively significantly improved as compared to Gaussian initial states.
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.
Dynamic behavior of the quantum Zakharov-Kuznetsov equations in dense quantum magnetoplasmas
Zhen, Hui-Ling; Tian, Bo Wang, Yu-Feng; Zhong, Hui; Sun, Wen-Rong
2014-01-15
Quantum Zakharov-Kuznetsov (qZK) equation is found in a dense quantum magnetoplasma. Via the spectral analysis, we investigate the Hamiltonian and periodicity of the qZK equation. Using the Hirota method, we obtain the bilinear forms and N-soliton solutions. Asymptotic analysis on the two-soliton solutions shows that the soliton interaction is elastic. Figures are plotted to reveal the propagation characteristics and interaction between the two solitons. We find that the one soliton has a single peak and its amplitude is positively related to H{sub e}, while the two solitons are parallel when H{sub e} < 2, otherwise, the one soliton has two peaks and the two solitons interact with each other. Hereby, H{sub e} is proportional to the ratio of the strength of magnetic field to the electronic Fermi temperature. External periodic force on the qZK equation yields the chaotic motions. Through some phase projections, the process from a sequence of the quasi-period doubling to chaos can be observed. The chaotic behavior is observed since the power spectra are calculated, and the quasi-period doubling states of perturbed qZK equation are given. The final chaotic state of the perturbed qZK is obtained.
Dynamics of a nonautonomous soliton in a generalized nonlinear Schroedinger equation
Yang Zhanying; Zhang Tao; Zhao Lichen; Feng Xiaoqiang; Yue Ruihong
2011-06-15
We solve a generalized nonautonomous nonlinear Schroedinger equation analytically by performing the Darboux transformation. The precise expressions of the soliton's width, peak, and the trajectory of its wave center are investigated analytically, which symbolize the dynamic behavior of a nonautonomous soliton. These expressions can be conveniently and effectively applied to the management of soliton in many fields.
Nonlinear tunneling of optical soliton in 3 coupled NLS equation with symbolic computation
Mani Rajan, M.S.; Mahalingam, A.; Uthayakumar, A.
2014-07-15
We investigated the soliton solution for N coupled nonlinear Schrödinger (CNLS) equations. These equations are coupled due to the cross-phase-modulation (CPM). Lax pair of this system is obtained via the Ablowitz–Kaup–Newell–Segur (AKNS) scheme and the corresponding Darboux transformation is constructed to derive the soliton solution. One and two soliton solutions are generated. Using two soliton solutions of 3 CNLS equation, nonlinear tunneling of soliton for both with and without exponential background has been discussed. Finally cascade compression of optical soliton through multi-nonlinear barrier has been discussed. The obtained results may have promising applications in all-optical devices based on optical solitons, study of soliton propagation in birefringence fiber systems and optical soliton with distributed dispersion and nonlinearity management. -- Highlights: •We consider the nonlinear tunneling of soliton in birefringence fiber. •3-coupled NLS (CNLS) equation with variable coefficients is considered. •Two soliton solutions are obtained via Darboux transformation using constructed Lax pair. •Soliton tunneling through dispersion barrier and well are investigated. •Finally, cascade compression of soliton has been achieved.
Soliton Theory of Two-Dimensional Lattices: The Discrete Nonlinear Schroedinger Equation
Arevalo, Edward
2009-06-05
We theoretically investigate the motion of collective excitations in the two-dimensional nonlinear Schroedinger equation with cubic nonlinearity. The form of these excitations for a broad range of parameters is derived. Their evolution and interaction is numerically studied and the modulation instability is discussed. The case of saturable nonlinearity is revisited.
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.
Explicit equation for particle settling velocities in solid-liquid systems
Zigrang, D.J.; Sylvester, N.D.
1981-11-01
Zanker has recently presented nomographs for determining particle settling velocities in solid-liquid systems. These nomographs were based on the general correlations developed by Barnea and Mizrahi and Barnea and Mednick. This work presents an equation directly computing particle settling velocities, eliminating the uncertainty associated with nomographs.
ICM: an Integrated Compartment Method for numerically solving partial differential equations
Yeh, G.T.
1981-05-01
An integrated compartment method (ICM) is proposed to construct a set of algebraic equations from a system of partial differential equations. The ICM combines the utility of integral formulation of finite element approach, the simplicity of interpolation of finite difference approximation, and the flexibility of compartment analyses. The integral formulation eases the treatment of boundary conditions, in particular, the Neumann-type boundary conditions. The simplicity of interpolation provides great economy in computation. The flexibility of discretization with irregular compartments of various shapes and sizes offers advantages in resolving complex boundaries enclosing compound regions of interest. The basic procedures of ICM are first to discretize the region of interest into compartments, then to apply three integral theorems of vectors to transform the volume integral to the surface integral, and finally to use interpolation to relate the interfacial values in terms of compartment values to close the system. The Navier-Stokes equations are used as an example of how to derive the corresponding ICM alogrithm for a given set of partial differential equations. Because of the structure of the algorithm, the basic computer program remains the same for cases in one-, two-, or three-dimensional problems.
Equations of State of Elements Based on the Generalized Fermi-Thomas Theory
DOE R&D Accomplishments [OSTI]
Feynman, R. P.; Metropolis, N.; Teller, E.
1947-04-28
The Fermi-Thomas model has been used to derive the equation of state of matter at high pressures and at various temperatures. Calculations have been carried out both without and with the exchange terms. Discussion of similarity transformations lead to the virial theorem and to correlation of solutions for different Z-values.
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.
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.
Kamon, M.; Phillips, J.R.
1994-12-31
In this paper techniques are presented for preconditioning equations generated by discretizing constrained vector integral equations associated with magnetoquasistatic analysis. Standard preconditioning approaches often fail on these problems. The authors present a specialized preconditioning technique and prove convergence bounds independent of the constraint equations and electromagnetic excitation frequency. Computational results from analyzing several electronic packaging examples are given to demonstrate that the new preconditioning approach can sometimes reduce the number of GMRES iterations by more than an order of magnitude.
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.
Courtney, Daniel G. Shea, Herbert
2015-09-07
Passively fed ionic liquid electrospray sources are capable of efficiently emitting a variety of ion beams with promising applications to spacecraft propulsion and as focused ion beams. Practical devices will require integrated or coupled ionic liquid reservoirs; the effects of which have not been explored in detail. Porous reservoirs are a simple, scalable solution. However, we have shown that their pore size can dramatically alter the beam composition. Emitting the ionic liquid 1-ethyl-3-methylimidazolium bis(triflouromethylsulfonyl)amide, the same device was shown to yield either an ion or droplet dominated beam when using reservoirs of small or large pore size, respectively; with the latter having a mass flow in excess of 15 times larger than the former at negative polarity. Another source, emitting nearly purely ionic beams of 1-ethyl-3-methylimidazolium tetrafluoroborate, was similarly shown to emit a significant droplet population when coupled to reservoirs of large (>100 μm) pores; constituting a reduction in propulsive efficiency from greater than 70% to less than 30%. Furthermore, we show that reservoir selection can alter the voltage required to obtain and sustain emission, increasing with smaller pore size.
Evaluation of the Use of Existing RELAP5-3D Models to Represent the Actinide Burner Test Reactor
C. B. Davis
2007-02-01
The RELAP5-3D code is being considered as a thermal-hydraulic system code to support the development of the sodium-cooled Actinide Burner Test Reactor as part of Global Nuclear Energy Partnership. An evaluation was performed to determine whether the control system could be used to simulate the effects of non-convective mechanisms of heat transport in the fluid that are not currently represented with internal code models, including axial and radial heat conduction in the fluid and subchannel mixing. The evaluation also determined the relative importance of axial and radial heat conduction and fluid mixing on peak cladding temperature for a wide range of steady conditions and during a representative loss-of-flow transient. The evaluation was performed using a RELAP5-3D model of a subassembly in the Experimental Breeder Reactor-II, which was used as a surrogate for the Actinide Burner Test Reactor. An evaluation was also performed to determine if the existing centrifugal pump model could be used to simulate the performance of electromagnetic pumps.
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].
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.
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.
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.
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.
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.
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.
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.
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.
Spin eigen-states of Dirac equation for quasi-two-dimensional electrons
Eremko, Alexander; Brizhik, Larissa; Loktev, Vadim
2015-10-15
Dirac equation for electrons in a potential created by quantum well is solved and the three sets of the eigen-functions are obtained. In each set the wavefunction is at the same time the eigen-function of one of the three spin operators, which do not commute with each other, but do commute with the Dirac Hamiltonian. This means that the eigen-functions of Dirac equation describe three independent spin eigen-states. The energy spectrum of electrons confined by the rectangular quantum well is calculated for each of these spin states at the values of energies relevant for solid state physics. It is shown that the standard Rashba spin splitting takes place in one of such states only. In another one, 2D electron subbands remain spin degenerate, and for the third one the spin splitting is anisotropic for different directions of 2D wave vector.
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.
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.