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OIL & GAS FIELD OUTLINES FROM BUFFERED WELLS The VBA Code below builds oil & gas field boundary outlines (polygons) from buffered wells (points). Input well points layer must be a...
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Electromagnetic Field Theory Fall 2014 Course Outline
Haimovich, Alexander
ECE 620 Electromagnetic Field Theory Fall 2014 Course Outline Instructor: Dr. Gerald Whitman Text of electromagnetic phenomena that vary sinusoidally in time. Course Learning Outcome: Students will learn fundamental knowledge of ac electromagnetic theory, which is needed for a broad spectrum of electrical engineering
Controlling Electromagnetic Fields at Boundaries of Arbitrary Geometries
Teo, Jonathon Yi Han; Molardi, Carlo; Genevet, Patrice
2015-01-01
Rapid developments in the emerging field of stretchable and conformable photonics necessitate analytical expressions for boundary conditions at metasurfaces of arbitrary geometries. Here, we introduce the concept of conformal boundary optics: a design theory that determines the optical response for designer input and output fields at such interfaces. Given any object, we can realise coatings to achieve exotic effects like optical illusions and anomalous diffraction behaviour. This approach is relevant to a broad range of applications from conventional refractive optics to the design of the next-generation of wearable optical components. This concept can be generalized to other fields of research where designer interfaces with nontrivial geometries are encountered.
Vacuum Casimir energy densities and field divergences at boundaries
Nicola Bartolo; Salvatore Butera; Margherita Lattuca; Roberto Passante; Lucia Rizzuto; Salvatore Spagnolo
2015-05-14
We consider and review the emergence of singular energy densities and field fluctuations at sharp boundaries or point-like field sources in the vacuum. The presence of singular energy densities of a field may be relevant from a conceptual point of view, because they contribute to the self-energy of the system. They should also generate significant gravitational effects. We first consider the case of the interface between a metallic boundary and the vacuum, and obtain the structure of the singular electric and magnetic energy densities at the interface through an appropriate limit from a dielectric to an ideal conductor. Then, we consider the case of a point-like source of the electromagnetic field, and show that also in this case the electric and magnetic energy densities show a singular structure at the source position. We discuss how, in both cases, these singularities give an essential contribution to the electromagnetic self-energy of the system; moreover, they solve an apparent inconsistency between the space integral of the field energy density and the average value of the field Hamiltonian. The singular behavior we find is softened, or even eliminated, for boundaries fluctuating in space and for extended field sources. We discuss in detail the case in which a reflecting boundary is not fixed in space but is allowed to move around an equilibrium position, under the effect of quantum fluctuations of its position. Specifically, we consider the simple case of a one-dimensional massless scalar field in a cavity with one fixed and one mobile wall described quantum-mechanically. We investigate how the possible motion of the wall changes the vacuum fluctuations and the energy density of the field, compared with the fixed-wall case. Also, we explicitly show how the fluctuating motion of the wall smears out the singular behaviour of the field energy density at the boundary.
Boundary-layer control by electric fields A feasibility study
Mendes, R V
1998-01-01
A problem of great concern in aviation and submarine propulsion is the control of the boundary layer and, in particular, the methods to extend the laminar region as a means to decrease noise and fuel consumption. In this paper we study the flow of air along an airfoil when a layer of ionized gas and a longitudinal electric field are created in the boundary layer region. By deriving scaling solutions and more accurate numerical solutions we discuss the possibility of achieving significant boundary layer control for realistic physical parameters. Practical design formulas and criteria are obtained. We also discuss the perspectives for active control of the laminar-to-turbulent transition fluctuations by electromagnetic field modulation.
Boundary String Field Theory of the DDbar System
Kraus, P; Kraus, Per; Larsen, Finn
2001-01-01
We develop the boundary string field theory approach to tachyon condensation on the DDbar system. Particular attention is paid to the gauge fields, which combine with the tachyons in a natural way. We derive the RR-couplings of the system and express the result in terms of Quillen's superconnection. The result is related to an index theorem, and is thus shown to be exact.
Boettcher, Markus
1 Magnetic Field Generation and Particle Energization at Relativistic Shear Boundaries. We find efficient magnetic field generation and particle energization at the shear boundary, driven generation (Colgate et al 2001, Medvedev & Loeb 1999) and nonthermal particle energization (Berezhko 1981
Garmestani, Hamid
Migration and reorientation of grain boundaries in Zn bicrystals during annealing in a high angles to the free surfaces are annealed in the field of 17 T. Boundaries migrate reorienting almost driven boundary migration. The absolute boundary mobility was measured to be about 2:5 Â 10À8 m4 /J s. Ó
Tachyon condensation in boundary string field theory at one loop
K. Bardakci; A. Konechny
2001-08-21
We compute the one-loop partition function for quadratic tachyon background in open string theory. Both closed and open string representations are developed. Using these representations we study the one-loop divergences in the partition function in the presence of the tachyon background. The divergences due to the open and closed string tachyons are treated by analytic continuation in the tachyon mass squared. We pay particular attention to the imaginary part of the analytically continued expressions. The last one gives the decay rate of the unstable vacuum. The dilaton tadpole is also given some partial consideration. The partition function is further used to study corrections to tachyon condensation processes describing brane descent relations. Assuming the boundary string field theory prescription for construction of the string field action via partition function holds at one loop level we study the one-loop corrections to the tachyon potential and to the tensions of lower-dimensional branes.
Richardson, John
The characteristics of sharp (small-scale) boundaries of solar wind plasma and magnetic field are the boundaries of small-scale and mid- dle-scale solar wind structures. We describe the behavior of the solar boundaries of small and medium scale solar wind plasma structures which we identify by looking for sharp
Boettcher, Markus
1 Magnetic Field Generation and Particle Energization at Relativistic Shear Boundaries+e) plasmas. We find efficient magnetic field generation and particle energization at the shear boundary generation (Colgate et al 2001, Medvedev & Loeb 1999) and nonthermal particle energization (Berezhko 1981
Static electric field in one-dimensional insulators without boundaries
Chen, Kuang-Ting
In this brief report, we show that in a one-dimensional insulating system with periodic boundary conditions, the coefficient of the ? term in the effective theory is not only determined by the topological index ?i?[superscript ...
THE BOUNDARY RIGIDITY PROBLEM IN THE PRESENCE OF A MAGNETIC FIELD
Uhlmann, Gunther
of reversible systems 36 6.4. Generic local boundary rigidity 38 Appendix A. Geometry of magnetic systems 42 A.1. SantalÂ´o's formula 45 A.5. Index form of a magnetic geodesic 46 Appendix B. Study of a certain classTHE BOUNDARY RIGIDITY PROBLEM IN THE PRESENCE OF A MAGNETIC FIELD NURLAN S. DAIRBEKOV, GABRIEL P
Boundary migration in Zn bicrystal induced by a high magnetic field A. D. Sheikh-Alia)
Garmestani, Hamid
Boundary migration in Zn bicrystal induced by a high magnetic field A. D. Sheikh-Alia) National migrated under the action of a magnetic driving force in the direction of the grain with higher diamagnetic.1063/1.1572536 Magnetically induced grain boundary migration has been established for diamagnetic bismuth13 and zinc.4
Athens, University of
Robust model-based detection of the lung field boundaries in portable chest radiographs supported of the lung field boundaries in portable chest radiographs supported by selective thresholding D K Iakovidis1-ray misinterpretation rates. This paper presents a novel methodology for the detection of the lung field boundaries
ARM - Field Campaign - Boundary Layer CO2 Using CW Lidar
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ARM - Field Campaign - Lower Atmospheric Boundary Layer Experiment
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Boundary values of mixed-symmetry massless fields in AdS space
Chekmenev, Alexander
2015-01-01
We elaborate on the ambient space approach to boundary values of $AdS_{d+1}$ gauge fields and apply it to massless fields of mixed-symmetry type. In the most interesting case of odd-dimensional bulk the respective leading boundary values are conformal gauge fields subject to the invariant equations. As a byproduct our approach gives a manifestly conformal and gauge covariant formulation for these fields. Although such formulation employs numerous auxiliary fields, it comes with a systematic procedure for their elimination that results in a more concise formulation involving only a reasonable set of auxiliaries, which eventually (at least in principle) can be reduced to the minimal formulation in terms of the irreducible Lorentz tensors. The simplest mixed-symmetry field, namely, the rank-3 tensor associated to the two-row Young diagram, is considered in some details.
COURSE OUTLINE Management 3313
COURSE OUTLINE Management 3313 Developing Leadership Skills Online Syllabus Faculty: Andrew L Classroom): http://oc.okstate.edu Administrative contact: CEPD Distance Learning Office, 108 Gundersen, cepd, the focus will be on self- management and interpersonal concepts as opposed to organizational leadership
Electromagnetic field of a charge intersecting a cold plasma boundary in a waveguide
Alekhina, Tatiana Yu.; Tyukhtin, Andrey V.
2011-06-15
We analyze the electromagnetic field of a charge crossing a boundary between a vacuum and cold plasma in a waveguide. We obtain exact expressions for the field components and the spectral density of the transition radiation. With the steepest descent technique, we investigate the field components. We show that the electromagnetic field has a different structure in a vacuum than in cold plasma. We also develop an algorithm for the computation of the field based on a certain transformation of the integration path. The behavior of the field depending on distance and time and the spectral density depending on frequency are explored for different charge velocities. Some important physical effects are noted. A considerable increase and concentration of the field near the wave front in the plasma is observed for the case of ultrarelativistic particles. In the plasma, the mode envelopes and spectral density show zero points when the charge velocity is within certain limits.
Reverse Engineering Quantum Field Theory
Robert Oeckl
2012-10-02
An approach to the foundations of quantum theory is advertised that proceeds by "reverse engineering" quantum field theory. As a concrete instance of this approach, the general boundary formulation of quantum theory is outlined.
Liang, Edison; Smith, Ian [Rice University, MS 108, 6100 Main Street, Houston, TX 77005 (United States); Boettcher, Markus, E-mail: liang@rice.edu, E-mail: iansmith@rice.edu, E-mail: boettchm@ohio.edu [Physics and Astronomy Department, Ohio University, Athens, OH 45701 (United States)
2013-04-01
Using particle-in-cell simulations, we study the kinetic physics of relativistic shear flow in collisionless electron-positron (e+e-) plasmas. We find efficient magnetic field generation and particle energization at the shear boundary, driven by streaming instabilities across the shear interface and sustained by the shear flow. Nonthermal, anisotropic high-energy particles are accelerated across field lines to produce a power-law tail turning over just below the shear Lorentz factor. These results have important implications for the dissipation and radiation of jets in blazars and gamma-ray bursts.
Gaw?dzki, Krzysztof
2015-01-01
We consider a model of quantum-wire junctions where the latter are described by conformal-invariant boundary conditions of the simplest type in the multicomponent compactified massless scalar free field theory representing the bosonized Luttinger liquids in the bulk of wires. The boundary conditions result in the scattering of charges across the junction with nontrivial reflection and transmission amplitudes. The equilibrium state of such a system, corresponding to inverse temperature $\\beta$ and electric potential $V$, is explicitly constructed both for finite and for semi-infinite wires. In the latter case, a stationary nonequilibrium state describing the wires kept at different temperatures and potentials may be also constructed. The main result of the present paper is the calculation of the full counting statistics (FCS) of the charge and energy transfers through the junction in a nonequilibrium situation. Explicit expressions are worked out for the generating function of FCS and its large-deviations asym...
B. Plaster
2013-09-22
We propose a new concept for determining the interior magnetic field vector components in neutron electric dipole moment experiments. If a closed three-dimensional boundary surface surrounding the fiducial volume of an experiment can be defined such that its interior encloses no currents or sources of magnetization, each of the interior vector field components and the magnetic scalar potential will satisfy a Laplace equation. Therefore, if either the vector field components or the normal derivative of the scalar potential can be measured on the surface of this boundary, thus defining a Dirichlet or Neumann boundary-value problem, respectively, the interior vector field components or the scalar potential (and, thus, the field components via the gradient of the potential) can be uniquely determined via solution of the Laplace equation. We discuss the applicability of this technique to the determination of the interior magnetic field components during the operating phase of neutron electric dipole moment experiments when it is not, in general, feasible to perform direct in situ measurements of the interior field components. We also study the specifications that a vector field probe must satisfy in order to determine the interior vector field components to a certain precision. The technique we propose here may also be applicable to experiments requiring monitoring of the vector magnetic field components within some closed boundary surface, such as searches for neutron-antineutron oscillations along a flight path or measurements in storage rings of the muon anomalous magnetic moment $g-2$ and the proton electric dipole moment.
Li, Bo
Yukawa-field approximation of electrostatic free energy and dielectric boundary force This article.1088/0951-7715/24/11/011 Yukawa-field approximation of electrostatic free energy and dielectric boundary force Hsiao-Bing Cheng1. The electrostatic free energy determines the dielectric boundary force that in turn influences crucially
MERIT Pump/Probe Data OutlineOutline
McDonald, Kirk
MERIT Pump/Probe Data Analysis OutlineOutline The pump/probe program Particle detector response correction Pump/probe analysis results NFMCC Collaboration Meeting , LBNL, January 26, 2009 Ilias Efthymiopoulos - CERN #12;The pump/probe program #12;The pump/probe program Use of the CERN PS flexibility
Krzysztof Gaw?dzki; Clément Tauber
2015-01-29
We consider a model of quantum-wire junctions where the latter are described by conformal-invariant boundary conditions of the simplest type in the multicomponent compactified massless scalar free field theory representing the bosonized Luttinger liquids in the bulk of wires. The boundary conditions result in the scattering of charges across the junction with nontrivial reflection and transmission amplitudes. The equilibrium state of such a system, corresponding to inverse temperature $\\beta$ and electric potential $V$, is explicitly constructed both for finite and for semi-infinite wires. In the latter case, a stationary nonequilibrium state describing the wires kept at different temperatures and potentials may be also constructed. The main result of the present paper is the calculation of the full counting statistics (FCS) of the charge and energy transfers through the junction in a nonequilibrium situation. Explicit expressions are worked out for the generating function of FCS and its large-deviations asymptotics. For the purely transmitting case they coincide with those obtained in the litterature, but numerous cases of junctions with transmission and reflection are also covered. The large deviations rate function of FCS for charge and energy transfers is shown to satisfy the fluctuation relations and the expressions for FCS obtained here are compared with the Levitov-Lesovic formulae.
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Office of Scientific and Technical Information (OSTI)
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Clouds, Precipitation, and Marine Boundary Layer Structure during the MAGIC Field Campaign
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Zhou, Xiaoli; Kollias, Pavlos; Lewis, Ernie R.
2015-03-01
The recent ship-based MAGIC (Marine ARM GCSS Pacific Cross-Section Intercomparison (GPCI) Investigation of Clouds) field campaign with the marine-capable Second ARM Mobile Facility (AMF2) deployed on the Horizon Lines cargo container M/V Spirit provided nearly 200 days of intraseasonal high-resolution observations of clouds, precipitation, and marine boundary layer (MBL) structure on multiple legs between Los Angeles, California, and Honolulu, Hawaii. During the deployment, MBL clouds exhibited a much higher frequency of occurrence than other cloud types and occurred more often in the warm season than in the cold season. MBL clouds demonstrated a propensity to produce precipitation, which often evaporatedmore »before reaching the ocean surface. The formation of stratocumulus is strongly correlated to a shallow MBL with a strong inversion and a weak transition, while cumulus formation is associated with a much weaker inversion and stronger transition. The estimated inversion strength is shown to depend seasonally on the potential temperature at 700 hPa. The location of the commencement of systematic MBL decoupling always occurred eastward of the locations of cloud breakup, and the systematic decoupling showed a strong moisture stratification. The entrainment of the dry warm air above the inversion appears to be the dominant factor triggering the systematic decoupling, while surface latent heat flux, precipitation, and diurnal circulation did not play major roles. MBL clouds broke up over a short spatial region due to the changes in the synoptic conditions, implying that in real atmospheric conditions the MBL clouds do not have enough time to evolve as in the idealized models. (auth)« less
Clouds, Precipitation, and Marine Boundary Layer Structure during the MAGIC Field Campaign
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Zhou, Xiaoli [McGill Univ., Montreal, Quebec (Canada); Dept. of Atmospheric and Oceanic Sciences; Kollias, Pavlos [McGill Univ., Montreal, Quebec (Canada); Dept. of Atmospheric and Oceanic Sciences; Lewis, Ernie R. [Brookhaven National Lab., Upton, NY (United States). Biological, Environmental, and Climate Sciences Dept.
2015-03-01
The recent ship-based MAGIC (Marine ARM GCSS Pacific Cross-Section Intercomparison (GPCI) Investigation of Clouds) field campaign with the marine-capable Second ARM Mobile Facility (AMF2) deployed on the Horizon Lines cargo container M/V Spirit provided nearly 200 days of intraseasonal high-resolution observations of clouds, precipitation, and marine boundary layer (MBL) structure on multiple legs between Los Angeles, California, and Honolulu, Hawaii. During the deployment, MBL clouds exhibited a much higher frequency of occurrence than other cloud types and occurred more often in the warm season than in the cold season. MBL clouds demonstrated a propensity to produce precipitation, which often evaporated before reaching the ocean surface. The formation of stratocumulus is strongly correlated to a shallow MBL with a strong inversion and a weak transition, while cumulus formation is associated with a much weaker inversion and stronger transition. The estimated inversion strength is shown to depend seasonally on the potential temperature at 700 hPa. The location of the commencement of systematic MBL decoupling always occurred eastward of the locations of cloud breakup, and the systematic decoupling showed a strong moisture stratification. The entrainment of the dry warm air above the inversion appears to be the dominant factor triggering the systematic decoupling, while surface latent heat flux, precipitation, and diurnal circulation did not play major roles. MBL clouds broke up over a short spatial region due to the changes in the synoptic conditions, implying that in real atmospheric conditions the MBL clouds do not have enough time to evolve as in the idealized models. (auth)
M. Hassan Farshbaf-Shaker; Christian Heinemann
2015-07-08
In this work we investigate a phase field model for damage processes in two-dimensional viscoelastic media with nonhomogeneous Neumann data describing external boundary forces. In the first part we establish global-in-time existence, uniqueness, a priori estimates and continuous dependence of strong solutions on the data. The main difficulty is caused by the irreversibility of the phase field variable which results in a constrained PDE system. In the last part we consider an optimal control problem where a cost functional penalizes maximal deviations from prescribed damage profiles. The goal is to minimize the cost functional with respect to exterior forces acting on the boundary which play the role of the control variable in the considered model. To this end, we prove existence of minimizers and study a family of "local" approximations via adapted cost functionals.
Outlining a scholarly workbench publication and data as a continuum
Paris-Sud XI, Université de
Outlining a scholarly workbench publication and data as a continuum Laurent Romary INRIA viewed from the point of view of research repositories · Publication repositories Where do we stand · A multidisciplinary field Publications: importance of conferences, long- standing culture of publication
Measurements of stress fields near a grain boundary: Exploring blocked arrays of dislocations in 3D
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Guo, Y.; Collins, D. M.; Tarleton, E.; Hofmann, F.; Tischler, J.; Liu, W.; Xu, R.; Wilkinson, A. J.; Britton, T. B.
2015-06-24
The interaction between dislocation pile-ups and grain boundaries gives rise to heterogeneous stress distributions when a structural metal is subjected to mechanical loading. Such stress heterogeneity leads to preferential sites for damage nucleation and therefore is intrinsically linked to the strength and ductility of polycrystalline metals. To date the majority of conclusions have been drawn from 2D experimental investigations at the sample surface, allowing only incomplete observations. Our purpose here is to significantly advance the understanding of such problems by providing quantitative measurements of the effects of dislocation pile up and grain boundary interactions in 3D. This is accomplished throughmore »the application of differential aperture X-ray Laue micro-diffraction (DAXM) and high angular resolution electron backscatter diffraction (HR-EBSD) techniques. Our analysis demonstrates a similar strain characterization capability between DAXM and HR-EBSD and the variation of stress intensity in 3D reveals that different parts of the same grain boundary may have different strengths in resisting slip transfer, likely due to the local grain boundary curvature.« less
Vacuum energy densities of a field in a cavity with a mobile boundary
Federico Armata; Roberto Passante
2015-01-15
We consider the zero-point field fluctuations, and the related field energy densities, inside a one-dimensional and a three-dimensional cavity with a mobile wall. The mechanical degrees of freedom of the mobile wall are described quantum mechanically and they are fully included in the overall system dynamics. In this optomechanical system, the field and the wall can interact with each other through the radiation pressure on the wall, given by the photons inside the cavity or even by vacuum fluctuations. We consider two cases: the one-dimensional electromagnetic field and the three-dimensional scalar field, and use the Green's functions formalism, which allows extension of the results obtained for the scalar field to the electromagnetic field. We show that the quantum fluctuations of the position of the cavity's mobile wall significantly affect the field energy density inside the cavity, in particular at the very proximity of the mobile wall. The dependence of this effect from the ultraviolet cutoff frequency, related to the plasma frequency of the cavity walls, is discussed. We also compare our new results for the one-dimensional electromagnetic field and the three-dimensional massless scalar field to results recently obtained for the one-dimensional massless scalar field. We show that the presence of a mobile wall also changes the Casimir-Polder force on a polarizable body placed inside the cavity, giving the possibility to detect experimentally the new effects we have considered.
Pulak Ranjan Giri
2007-02-05
We perform a 1-parameter family of self-adjoint extensions characterized by the parameter $\\omega_0$. This allows us to get generic boundary conditions for the quantum oscillator on $N$ dimensional complex projective space($\\mathbb{C}P^N$) and on its non-compact version i.e., Lobachewski space($\\mathcal L_N$) in presence of constant magnetic field. As a result, we get a family of energy spectrums for the oscillator. In our formulation the already known result of this oscillator is also belong to the family. We have also obtained energy spectrum which preserve all the symmetry (full hidden symmetry and rotational symmetry) of the oscillator. The method of self-adjoint extensions have been discussed for conic oscillator in presence of constant magnetic field also.
Engineering Economy Outline IE 305-Part 1
Vardeman, Stephen B.
Engineering Economy Outline IE 305-Part 1 Stephen B. Vardeman ISU Fall 2013 Stephen B. Vardeman (ISU) Engineering Economy Outline Fall 2013 1 / 53 #12;THE Basics The very basic notion that governs) Engineering Economy Outline Fall 2013 2 / 53 #12;Solving for P The (N
Kaluza-Klein masses of bulk fields with general boundary conditions in AdS{sub 5} space
Chang, Sanghyeon; Park, Seong Chan; Song, Jeonghyeon
2005-05-15
Recently bulk Randall-Sundrum theories with the gauge group SU(2){sub L}xSU(2){sub R}xU(1){sub B-L} have drawn a lot of interest as an alternative to the electroweak symmetry breaking mechanism. These models are in better agreement with electroweak precision data since custodial isospin symmetry on the IR-brane is protected by the extended bulk gauge symmetry. We comprehensively study, in the S{sup 1}/Z{sub 2}xZ{sub 2}{sup '} orbifold, the bulk gauge and fermion fields with the general boundary conditions as well as the bulk and localized mass terms. Master equations to determine the Kaluza-Klein (KK) mass spectra are derived without any approximation, which is an important basic step for various phenomenologies at high energy colliders. The correspondence between orbifold boundary conditions and localized mass terms is demonstrated not only in the gauge sector but also in the fermion sector. As the localized mass increases, the first KK fermion mass is shown to decrease while the first KK gauge boson mass is shown to increase. The degree of gauge coupling universality violation is computed to be small in most parameter space, and its correlation with the mass difference between the top quark and light quark KK mode is also studied.
Kumar, Dinesh; Bhattacharyya, R. [Udaipur Solar Observatory, Physical Research Laboratory, Dewali, Bari Road, Udaipur-313001 (India)] [Udaipur Solar Observatory, Physical Research Laboratory, Dewali, Bari Road, Udaipur-313001 (India); Smolarkiewicz, P. K. [European Centre for Medium-Range Weather Forecasts, Reading RG2 9AX (United Kingdom)] [European Centre for Medium-Range Weather Forecasts, Reading RG2 9AX (United Kingdom)
2013-11-15
In ideal magnetohydrodynamics characterized by an infinite electrical conductivity, the magnetic flux across an arbitrary fluid surface is conserved in time. The magnetofluid then can be partitioned into contiguous subvolumes of fluid, each of which entraps its own subsystem of magnetic flux. During dynamical evolution of the magnetofluid, these subvolumes press into each other; and in the process, two such subvolumes may come into direct contact while ejecting a third interstitial subvolume. Depending on the orientations of magnetic fields of the two interacting subvolumes, the magnetic field at the common surface of interaction may become discontinuous and a current sheet is formed there. This process of current sheet formation and their subsequent decay is believed to be a plausible mechanism for coronal heating and may also be responsible for various eruptive phenomena at the solar corona. In this work, we explore this theoretical concept through numerical simulations of a viscous, incompressible magnetofluid characterized by infinite electrical conductivity. In particular, we show that if the initial magnetic field is prescribed by superposition of two linear force-free fields with different torsion coefficients, then formation of current sheets are numerically realizable in the neighborhood of magnetic nulls.
Kiliyanpilakkil, V P; Ruiz-Columbié, A; Araya, G; Castillo, L; Hirth, B; Burgett, W
2015-01-01
We have analyzed long-term wind speed time-series from five field sites up to a height of 300 m from the ground. Structure function-based scaling analysis has revealed that the scaling exponents in the mesoscale regime systematically depend on height. This anomalous behavior is shown to be caused by the buoyancy effects. In the framework of the extended self-similarity, the relative scaling exponents portray quasi-universal behavior.
O. Olendski
2015-04-07
Thermodynamic properties of the one-dimensional (1D) quantum well (QW) with miscellaneous permutations of the Dirichlet (D) and Neumann (N) boundary conditions (BCs) at its edges in the perpendicular to the surfaces electric field $\\mathscr{E}$ are calculated. For the canonical ensemble, analytical expressions involving theta functions are found for the mean energy and heat capacity $c_V$ for the box with no applied voltage. Pronounced maximum accompanied by the adjacent minimum of the specific heat dependence on the temperature $T$ for the pure Neumann QW and their absence for other BCs are predicted and explained by the structure of the corresponding energy spectrum. Applied field leads to the increase of the heat capacity and formation of the new or modification of the existing extrema what is qualitatively described by the influence of the associated electric potential. A remarkable feature of the Fermi grand canonical ensemble is, at any BC combination in zero fields, a salient maximum of $c_V$ observed on the $T$ axis for one particle and its absence for any other number $N$ of corpuscles. Qualitative and quantitative explanation of this phenomenon employs the analysis of the chemical potential and its temperature dependence for different $N$. It is proved that critical temperature $T_{cr}$ of the Bose-Einstein (BE) condensation increases with the applied voltage for any number of particles and for any BC permutation except the ND case at small intensities $\\mathscr{E}$ what is explained again by the modification by the field of the interrelated energies. It is shown that even for the temperatures smaller than $T_{cr}$ the total dipole moment $\\langle P\\rangle$ may become negative for the quite moderate $\\mathscr{E}$. For either Fermi or BE system, the influence of the electric field on the heat capacity is shown to be suppressed with $N$ growing.
Confinement of the Sun's interior magnetic field: some exact boundary-layer solutions
T. S. Wood; M. E. McIntyre
2007-09-10
High-latitude laminar confinement of the Sun's interior magnetic field is shown to be possible, as originally proposed by Gough and McIntyre (1998) but contrary to a recent claim by Brun and Zahn (A&A 2006). Mean downwelling as weak as 2x10^-6cm/s -- gyroscopically pumped by turbulent stresses in the overlying convection zone and/or tachocline -- can hold the field in advective-diffusive balance within a confinement layer of thickness scale ~ 1.5Mm ~ 0.002 x (solar radius) while transmitting a retrograde torque to the Ferraro-constrained interior. The confinement layer sits at the base of the high-latitude tachocline, near the top of the radiative envelope and just above the `tachopause' marking the top of the helium settling layer. A family of exact, laminar, frictionless, axisymmetric confinement-layer solutions is obtained for uniform downwelling in the limit of strong rotation and stratification. A scale analysis shows that the flow is dynamically stable and the assumption of laminar flow realistic. The solution remains valid for downwelling values of the order of 10^-5cm/s but not much larger. This suggests that the confinement layer may be unable to accept a much larger mass throughput. Such a restriction would imply an upper limit on possible internal field strengths, perhaps of the order of hundreds of gauss, and would have implications also for ventilation and lithium burning. The solutions have interesting chirality properties not mentioned in the paper owing to space restrictions, but described at http://www.atmos-dynamics.damtp.cam.ac.uk/people/mem/papers/SQBO/solarfigure.html
Outline of Quantum Mechanics William G. Faris 1
Ueltschi, Daniel
Contents Outline of Quantum Mechanics William G. Faris 1 Inequalities for SchrÂ¨odinger Operators 141 Remarks on the Additivity Conjectures for Quantum Channels Christopher King 177 On the Static mechanics and bring clarity to certain mathematics that has been moti- vated by this field. This too
Quantum logic. A brief outline Karl Svozil #
Svozil, Karl
evidence of the quantum world. We give a brief outline of quantum logic, and some of its algebraic outline of its nonclassical aspects; in particular violations of BooleBell type consistency constraints and algebraic order of events from empirical facts. This is very different from the ``classical'' logical
Course Outline Psychology 501 Advanced Personality
Hopfinger, Joseph B.
theorists of the twentieth century and integrating what we know about their personal livesCourse Outline Psychology 501 Advanced Personality Sample Syllabus Assigned Text: Monte & Sollod and external situations control our behavior? · Are there reliable clusters of personality types among us
Design with Advanced Ceramics Course Outline
New South Wales, University of
MATS4002 Design with Advanced Ceramics Course Outline Session 1, 2015 School of Materials Science 11 March Ferroelectric Ceramics and their Applications (DW) 3 17 March 18 March Piezoelectric Ceramics (DW) 4 24 March 25 March Electro-optic Ceramics and Fibre-Optic Sensors (DW) 5 31 March 1 April
Outline PhD Research Plan D-ERDW PhD Research Plan Outline
Gilli, Adrian
Outline PhD Research Plan D-ERDW PhD Research Plan Outline Doctoral students compile a research (PhD Research Proposal Defense). Final approval is by the doctoral committee of the department or economic need. 2 PhD thesis Explain the main question you want to answer. Connect it with current state
THE URBAN BOUNDARY-LAYER FIELD CAMPAIGN IN MARSEILLE (UBL/CLU-ESCOMPTE): SET-UP AND FIRST RESULTS
) Abstract. The UBL/CLU (urban boundary layer/couche limite urbaine) observation and modelling campaign to the heat and moisture exchanges between the urban canopy and the atmosphere during periods of low wind mapping of urban land cover, land-use and aerodynamic parameters used in UBL models, and (iv) testing
Motivation and Outline PAW OEP Formalism and Implementation
Holzwarth, Natalie
Motivation and Outline PAW OEP Formalism and Implementation Conclusion Implementation #12;Motivation and Outline PAW OEP Formalism and Implementation Conclusion Motivation and Outline Motivation 1 The optimized effective potential (OEP) or exact exchange (EXX) formalism is a method which can
PERCENT FEDERAL LAND FOR OIL/GAS FIELD OUTLINES
U.S. Energy Information Administration (EIA) Indexed Site
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page| Open Energy Informationmonthly gasoline price toStocks 2009Cubic Foot) Year JanYear Jan FebPERCENT FEDERAL
SMOOTH OIL & GAS FIELD OUTLINES MADE FROM BUFFERED WELLS
U.S. Energy Information Administration (EIA) Indexed Site
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page| Open Energy Informationmonthly gasoline price toStocks 2009CubicAnalysis &V 1997
Texas 4-H Horse Project Teaching Outlines
Howard, Jeff W.; Johnson, Ken; Mason, Vanessa; Mitchell, Julianne
2000-06-15
Department, and Vanessa Mason, former Extension Assis- tant in Animal Science State Horse Office. Editorial contributions were made by Doug Householder and Pete Gibbs, Extension Horse Specialists. III CONTENTS The Digestive System of the Horse 1 Feeding... Management 30 minutes THE DIGESTIVE SYSTEM OF THE HORSE Subject Matter Outline Youth should be able to: a73 Identify the digestive system of the horse a73 List the parts of the foregut and hindgut a73 Recognize the functions of each compartment a73 Identify...
Vacuum Structure and Boundary Renormalization Group
M. Asorey; J. M. Munoz-Castaneda
2007-12-28
The vacuum structure is probed by boundary conditions. The behaviour of thermodynamical quantities like free energy, boundary entropy and entanglement entropy under the boundary renormalization group flow are analysed in 2D conformal field theories. The results show that whereas vacuum energy and boundary entropy turn out to be very sensitive to boundary conditions, the vacuum entanglement entropy is independent of boundary properties when the boundary of the entanglement domain does not overlap the boundary of the physical space. In all cases the second law of thermodynamics holds along the boundary renormalization group flow.
Zhang, Junshan
Objective: 1. Students can apply fundamental electromagnetic theory to solution of practical problems CourseEEE 340 Electromagnetic Engineering I (4) [F, S] Course (Catalog) Description: Static and time; MAT 362; PHY 131, 132. Textbook: Cheng, Field and Wave Electromagnetics. Supplemental Materials: None
Martin, Elijah H; Goniche, M.; Klepper, C Christopher; Hillairet, J.; Isler, Ralph C; Caughman, J. B. O.; Colas, L.; Ekedahl, A.; Colledani, G.; Lotte, Ph.; Litaudon, X; Hillis, Donald Lee; Harris, Jeffrey H
2015-01-01
Interaction of radio-frequency (RF) waves with the plasma in the near-field of a high-power wave launcher is now seen to be important, both in understanding the channeling of these waves through the plasma boundary and in avoiding power losses in the edge. In a recent Letter a direct non-intrusive measurement of a near antenna RF electric field in the range of lower hybrid (LH) frequencies ($E_{LH}$) was announced (Phys. Rev. Lett., 110:215005, 2013). The measurement was achieved through the fitting of Balmer series deuterium spectral lines utilizing a time dependent (dynamic) Stark effect model. In this article, the processing of the spectral data is discussed in detail and applied to a larger range of measurements and the accuracy and limitations of the experimental technique is investigated. It was found through an analysis of numerous Tore Supra pulses that good quantitative agreement exists between the measured and full-wave modeled $E_{LH}$ when the launched power exceeds 0.5MW. For low power the measurement becomes formidable utilizing the implemented passive spectroscopic technique because the spectral noise overwhelms the effect of the RF electric field on the line profile. Additionally, effects of the ponderomotive force are suspected at sufficiently high power.
Motivation and Outline Hatree-Fock Theory and KLI Approximation
Holzwarth, Natalie
Motivation and Outline Hatree-Fock Theory and KLI Approximation Frozen core orbital approximation March 24, 2011 Xiao Xu, N. A. W. Holzwarth PAW + HF & KLI #12;Motivation and Outline Hatree-Fock Theory of HF and KLI Conclusion Outline 1 Motivation of this work: Why? orbital dependent functionals + PAW 2
O. Olendski
2015-04-07
Analytical solutions of the Schr\\"{o}dinger equation for the one-dimensional quantum well with all possible permutations of the Dirichlet and Neumann boundary conditions (BCs) in perpendicular to the interfaces uniform electric field $\\mathscr{E}$ are used for the comparative investigation of their interaction and its influence on the properties of the system. Limiting cases of the weak and strong voltages allow an easy mathematical treatment and its clear physical explanation; in particular, for the small $\\mathscr{E}$, the perturbation theory derives for all geometries a linear dependence of the polarization on the field with the BC-dependent proportionality coefficient being positive (negative) for the ground (excited) states. Simple two-level approximation elementary explains the negative polarizations as a result of the field-induced destructive interference of the unperturbed modes and shows that in this case the admixture of only the neighboring states plays a dominant role. Different magnitudes of the polarization for different BCs in this regime are explained physically and confirmed numerically. Hellmann-Feynman theorem reveals a fundamental relation between the polarization and the speed of the energy change with the field. It is proved that zero-voltage position entropies $S_x$ are BC independent and for all states but the ground Neumann level (which has $S_x=0$) are equal to $\\ln2-1$ while the momentum entropies $S_k$ depend on the edge requirements and the level. Varying electric field changes position and momentum entropies in the opposite directions such that the entropic uncertainty relation is satisfied.
Paglieroni, David W. (Pleasanton, CA); Manay, Siddharth (Livermore, CA)
2011-12-20
A stochastic method and system for detecting polygon structures in images, by detecting a set of best matching corners of predetermined acuteness .alpha. of a polygon model from a set of similarity scores based on GDM features of corners, and tracking polygon boundaries as particle tracks using a sequential Monte Carlo approach. The tracking involves initializing polygon boundary tracking by selecting pairs of corners from the set of best matching corners to define a first side of a corresponding polygon boundary; tracking all intermediate sides of the polygon boundaries using a particle filter, and terminating polygon boundary tracking by determining the last side of the tracked polygon boundaries to close the polygon boundaries. The particle tracks are then blended to determine polygon matches, which may be made available, such as to a user, for ranking and inspection.
MPLP Curriculum Outline Defining Ourselves and Our Work
Riley, Shawn J.
MPLP Curriculum Outline Defining Ourselves and Our Work Introduction of Fellows Determine Personal Leadership Style Review Program Goals and Curriculum Establish and Share Individual Goals Understanding
Outline of the talk Statistics on Graphs, Exponential Formula and
Poinsot, Laurent
Outline of the talk Statistics on Graphs, Exponential Formula and Combinatorial Physics G and Complexity" Laurent Poinsot Statistics on Graphs, Exponential Formula and Combinatorial Physics #12;Exponential Formula : Informal Version Ingredients for the exponential formula Partial commutative monoids
Physics 112 Thermodynamics and Statistical Physics Winter 2000 COURSE OUTLINE
California at Santa Cruz, University of
Physics 112 Thermodynamics and Statistical Physics Winter 2000 COURSE OUTLINE TOPIC READINGS 1 and probability theory can be found in Chapter 16 of Mathematical Methods in the Physical Sciences, by Mary L
Outline for Linear Equations and Inequalities of 2 variables
charlotb
2010-04-15
Outline for Linear Equations and Inequalities of 2 variables. A. 1. Substitute any value for x in the equation and solve for y. This results in a point (x, y). OR.
National Nuclear Security Administration (NNSA)
09%2A en Ten-Year Site Plans (TYSP) http:www.nnsa.energy.govaboutusouroperationsinfopsinfopstysp
Chronological outlines of American literature, 1894-1914
Cannady, Ada
1915-05-15
CHRONOLOGICAL OUTLINES OF AMERICAN LITERATURE 1894 - 1914 fey Ada Cannady, A. B., College of Emporia, 1914. A thesis submitted to the Department of English and the Faculty of the Graduate School In partial ful- fillnent of the requirements... for the Master's de- gree . May 15, 1915. PREFACE. In attempting to outline the work done by Amer- ican writers during the past twenty-one years, my de- sire has been to place before the students of American Literature, in as brief and concise a form...
Page | 1 Managed Print Project Outline Pull Printing
Glasgow, University of
in power and reductions in total print volume. 2. Reduce costs by implementing a cost the completion of these initiatives. The UK government's introduction of the Carbon Reduction Commitments (CRC.0 Project Outline Following a number of pilot exercises, the University is preparing to move to new printing
OUTLINE FOR Chapter 5 AERODYNAMICS (W4-2-1)
Leu, Tzong-Shyng "Jeremy"
Vortex Filament Vortex line Vortex filament: a infinitesimal vortex tube. Vortex tube Reference: "Low Vortex in 3D Airfoil / Lifting Line theory 4 #12;2013/6/3 3 INDUCED VELOCITY, EFFECTIVE ANGLE OF ATTACK4_2_4) OUTLINE FOR Chapter 5 AERODYNAMICS (W4-3-1) #12;2013/6/3 5 Helmholtz Vortex Theorem
Master's programme in Electric Power Engineering Programme outline
Lagergren, Jens
of a power system with long transmission lines.The thesis defence took place at KTH in 1928.) Thus, afterMaster's programme in Electric Power Engineering Programme outline This programme consists three subject areas, namely: 1. Electric power systems (focusing on power system dynamics, stability
COURSE OUTLINE EE 4PM4 Electrical Power Systems
Haykin, Simon
COURSE OUTLINE EE 4PM4 Electrical Power Systems Academic Year 2014-15; Term 2; Jan. to May 2015 systems. To gain an appreciation of electrical power system protection techniques. Define and qualify issues relating to electrical power quality and the impact thereof on plant and customer loads. To study
Nuclear Graphite -Fission Reactor Brief Outline of Experience and
McDonald, Kirk
Nuclear Graphite - Fission Reactor Brief Outline of Experience and Understanding Professor Barry J Marsden and Dr. Graham N Hall Nuclear Graphite Research Group The University of Manchester 20 March 201313 9PL Tel: +44 (0) 161 275 4399, barry.marsden@manchester.ac.uk #12;Overview Â· Nuclear Graphite
1. Introduction This paper outlines the developments we have
Thornton, John
1. Introduction This paper outlines the developments we have made to our Robot Soccer Team since the team susceptible to both goals scored from the opposition as well as goals caused from the ball behaviours. This has been implemented in the form of a finite-state machine and has provided the team
Geography 5: People and Earth's Ecosystems Lecture Outline
, and Smart Growth" 2 Population growth Health Air pollution Water Food and agriculture Waste Energy 3 Outline fires often create a tremendous amount of air pollution in Third World cities. · Access to clean water · Average U.S. driver spends 443 hours per year (~55 workdays!) behind the wheel. · Traffic congestion costs
O'Leary outlines policy views at confirmation hearing
Simpson, J.
1993-02-15
In her confirmation hearing, Secretary O'Leary outlined her views on various controversial issues. Among these were management of Yucca Mountain and the search for a nuclear waste repository, research on alternative fuels, encouragement of the use of renewable energy sources, and her views on intergrated resource planning.
Outline Overview Design Principles Key Points Design Principles
Almulhem, Ahmad
Engineering Department, KFUPM Spring 2008 Ahmad Almulhem - Network Security Engineering - 2008 1 / 12 #12-Safe Defaults Economy of Mechanism Complete Mediation Open Design Separation of Privilege Least Common Mechanism Psychological Acceptability 3 Key Points Ahmad Almulhem - Network Security Engineering - 2008 2 / 12 #12;Outline
Recent Flare Studies at NJIT Outline of Studies
continuum brightening (white-light flares) Black-light solar flares (BLFs; Henoux et al. 1990): electron flares. - Solar limb in D3, showing a narrow, bright band above the photosphere between 1000 and 2500 km3/28/2014 1 Recent Flare Studies at NJIT Lecture 10 Outline of Studies Black Light Flares Moreton
outline 2014/09/30 1 Introduction to Physical
outline 2014/09/30 1 Ocean 620 Introduction to Physical Oceanography Fall, 2014 Niklas Schneider substantial sections on biology and chemistry, this book gives an introduction to PO that is thorough, concise list is subject to change, both as to content and as to order of the topics. 1. Why does ocean physics
Geography 5: People and Earth's Ecosystems Lecture Outline
Incinerators, cont'd · Refuse-Derived Fuel - Refuse is sorted to remove recyclable and unburnable materials waste" 2 Outline: 1. Solid waste and how we dispose of it 2. Shrinking the waste stream 3. Hazardous and toxic wastes 3 U.S. produces ~11 B tons solid waste annually · ~1/2 is agricultural waste (crop residues
integrated Wireless Information Network (iWIN) Lab A Robust Boundary Detection
Wu, Hongyi
· Related work · Motivation · Coconut algorithm · Simulation · Conclusion #12;integrated Wireless;integrated Wireless Information Network (iWIN) Lab OUTLINE · Introduction · Coconut algorithm · Coarse · Conclusion #12;integrated Wireless Information Network (iWIN) Lab COCONUT ALGORITHM · Coarse Boundary Surface
Outline History Basic Theory Research Future Accelerators References Brief Overview of Wakefield
Budker, Dmitry
Outline History Basic Theory Research Future Accelerators References Brief Overview of Wakefield Overview of Wakefield Acceleration #12;Outline History Basic Theory Research Future Accelerators References of Wakefield Acceleration #12;Outline History Basic Theory Research Future Accelerators References Wakefield
Gunawardena, Jeremy
Supplementary Figure 1 Steen Supplementary Figure 1. Pseudocode outlining of the computational algorithm. Pseudocode outlining the main steps of our procedure for detecting unannotated translation
Cylinder kernel expansion of Casimir energy with a Robin boundary
Liu, Zhonghai
2006-10-30
We compute the Casimir energy of a massless scalar field obeying the Robin boundary condition on one plate and the Dirichlet boundary condition on another plate for two parallel plates with a separation of alpha. The ...
An outflow boundary condition and algorithm for incompressible two ...
S. Dong
2014-03-05
Feb 22, 2014 ... conditions for the phase field function on each boundary, which ...... These velocity histories indicate that the oil–water two-phase flow has ...
North York (Yonge Street) building outlines with heights, clutter data, DEM, contours and places
Title: North York (Yonge Street) building outlines with heights, clutter data, DEM, contours heights, contours, building outlines, landmarks, points of interest Restrictions: Data is licensed for use@yorku.ca) Citation: RMSI. "[North York (Yonge Street) building outlines with heights, clutter data, DEM, contours
Downtown Toronto building outlines with heights, clutter data, DEM, contours and places
Title: Downtown Toronto building outlines with heights, clutter data, DEM, contours and places Data, building outlines, landmarks, points of interest Restrictions: Data is licensed for use of York University. "[Downtown Toronto building outlines with heights, clutter data, DEM, contours and places]" [electronic
Kortenkamp, David
60Dr. Gregory A. Dorais, NASA Ames Research Center Dr. David Kortenkamp, NASA Johnson Space Center NASA HCA Applications OutlineNASA HCA Applications Outline l 3T Control Architecture architecture Satellite Assistant (under development) #12;61Dr. Gregory A. Dorais, NASA Ames Research Center Dr. David
GMM 2010 Curriculum The outline provisions of the academic regulations
Bataillon, Thomas
The GMM programme entitles to the title of Bachelor of Engineering in Global Management and Manufacturing within relevant engineering fields, and independently solve existing engineering related tasks 3 and control, supply chain management, economy, sourcing and strategy) and relevant insights into other related
ARM - Field Campaign - Boundary Layer Cloud IOP
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach HomeA Better Anode Design to Improve4AJ01) (See22, 2012IIIAtlanticMarine
Testing outer boundary treatments for the Einstein equations
Oliver Rinne; Lee Lindblom; Mark A. Scheel
2007-07-25
Various methods of treating outer boundaries in numerical relativity are compared using a simple test problem: a Schwarzschild black hole with an outgoing gravitational wave perturbation. Numerical solutions computed using different boundary treatments are compared to a `reference' numerical solution obtained by placing the outer boundary at a very large radius. For each boundary treatment, the full solutions including constraint violations and extracted gravitational waves are compared to those of the reference solution, thereby assessing the reflections caused by the artificial boundary. These tests use a first-order generalized harmonic formulation of the Einstein equations. Constraint-preserving boundary conditions for this system are reviewed, and an improved boundary condition on the gauge degrees of freedom is presented. Alternate boundary conditions evaluated here include freezing the incoming characteristic fields, Sommerfeld boundary conditions, and the constraint-preserving boundary conditions of Kreiss and Winicour. Rather different approaches to boundary treatments, such as sponge layers and spatial compactification, are also tested. Overall the best treatment found here combines boundary conditions that preserve the constraints, freeze the Newman-Penrose scalar Psi_0, and control gauge reflections.
Boundaries and Topological Algorithms
Fleck, Margaret Morrison
1988-09-01
This thesis develops a model for the topological structure of situations. In this model, the topological structure of space is altered by the presence or absence of boundaries, such as those at the edges of objects. ...
Outline Motivation Theory Validation Application Conclusions Correlation screening in high dimension
Tourneret, Jean-Yves
Outline Motivation Theory Validation Application Conclusions Correlation screening in high dimension Alfred Hero University of Michigan - Ann Arbor June 14, 2011 1 / 45 #12;Outline Motivation Theory Validation Application Conclusions 1 Motivation 2 Theory 3 Validation 4 Application 5 Conclusions 2 / 45 #12
Title: York University building outlines with heights and clutter (land use) data Data Creator /
Title: York University building outlines with heights and clutter (land use) data Data Creator(s): April 2010 Updates: N/A Abstract: Data consists of: 3D Building Outlines in the York University Keele. Clutter data categories include: 1 Inland Water 2 Open 3 Low tree density 4 High Tree density 5 Buildings
School of Architecture Strategic Plan Outline page 1 School of Architecture
Maxwell, Bruce D.
School of Architecture Strategic Plan Outline page 1 School of Architecture Montana State University Strategic Planning Document Condensed Outline May 24, 2013 School of Architecture Vision Recognizing that architecture is a basic human need, we strive to play an essential and innovative role
NEURAL PCA NETWORK FOR LUNG OUTLINE RECONSTRUCTION IN VQ SCAN IMAGES
Serpen, Gursel
NEURAL PCA NETWORK FOR LUNG OUTLINE RECONSTRUCTION IN VQ SCAN IMAGES G. Serpen1 , Ph. D., R. Iyer1 system takes the digitized ventilation-perfusion scan images of lungs as input, identify a template according to the size and shape of the lungs and thereby approximate and reconstruct the outline of the lung
Applied Mathematics 4611F page 1 of 2 Course Outline 2013-14 Dr. Z. Krougly
Krougly, Zinovi
projects and a presentation. Course Outline by Topical Areas: Basic C++, Fundamental Types and Basic Modeling, Environmental Science, etc. Method of Evaluation: 5% Assignment 1 Â September 30, 2013 5 Senate Academic Handbook has specified that the following points should be added to all course outlines
Applied Mathematics 4611F page 1 of 2 Course Outline 2012-13 Prof. Z. Krougly
Krougly, Zinovi
assignments, two projects and a presentation. Course Outline by Topical Areas: Â· Basic C++, Fundamental Types in Physics, Biomedicine, Economics, Financial Modeling, Environmental Science, etc. Method of Evaluation: 5 Course Outlines: The UWO Senate Academic Handbook has specified that the following points should be added
Extensions of mapping classes from the boundary of a Biringer san & Lecuire san
Paoluzzi, Luisa
Extensions of mapping classes from the boundary of a handlebody Biringer san & Lecuire san Biringer san & Lecuire san () Extensions of mapping classes 1 / 32 #12;Contents 1 Questions 2 Statements 3 Definitions 4 Outline of the proof 5 Yet unanswered questions 6 Biproduct of the proof Biringer san & Lecuire
Casimir Energy due to a Semi-Infinite Plane Boundary
H. Ahmedov; I. H. Duru
2006-08-25
Following the derivation of the Green function for the massless scalar field satisfying the Dirichlet boundary condition on the Plane (x > 0, y = 0), we calculate the Casimir energy.
A study on boundary separation in an idealized ocean model
Düben, Peter D
2015-01-01
In numerical ocean models coast lines change the direction from one grid cell to its neighbor and the value for viscosity is set to be as small as possible. Therefore, model simulations are not converged with resolution and boundary separation points differ in essential properties from flow separation in continuous flow fields. In this paper, we investigate the quality of the representation of boundary separation points in global ocean models. To this end, we apply well established criteria for boundary separation within an idealized ocean model setup. We investigate an eddy-resolving as well as a steady test case with idealized and unstructured coast lines in a shallow water model that is based on a finite element discretization method. The results show that well established criteria for separation fail to detect boundary separation points due to an insufficient representation of ocean flows along free-slip boundaries. Along no-slip boundaries, most separation criteria provide adequate results. However, a ve...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D B L OBransenBusinessInitialRadiological Surveys atCLAMR
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass mapSpeeding access| DepartmentPeerFederal FleetUp inrdPilotWriting
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass mapSpeeding access| DepartmentPeerFederal FleetUp inrdPilotWritingEXTERNAL VERSION
City of Anaheim This page outlines solar PV incentives, financing mechanisms, permitting process Apply for local permits Install your PV system Arrange for your PV system to be interconnected to your
Disjoint BoundaryBoundary Paths in Critical Circular Planar Networks
Morrow, James A.
Disjoint BoundaryÂBoundary Paths in Critical Circular Planar Networks Ryan Sturgell December 8 that in a critical circular planar network every interior vertex has three disjoint paths to the boundary. 1, 1998 Abstract This paper explores some properties of critical circular planar netÂ works. The main
Ising Interfaces and Free Boundary Conditions
Clément Hongler; Kalle Kytölä
2011-10-17
We study the interfaces arising in the two-dimensional Ising model at critical temperature, without magnetic field. We show that in the presence of free boundary conditions between plus and minus spins, the scaling limit of these interfaces can be described by a variant of SLE, called dipolar SLE(3). This generalizes a celebrated result of Chelkak and Smirnov and proves a conjecture of Bauer, Bernard and Houdayer. We mention two possible applications of our result.
Laminar boundary layers in convective heat transport
Christian Seis
2012-12-12
We study Rayleigh-Benard convection in the high-Rayleigh-number and high-Prandtl-number regime, i.e., we consider a fluid in a container that is exposed to strong heating of the bottom and cooling of the top plate in the absence of inertia effects. While the dynamics in the bulk are characterized by a chaotic convective heat flow, the boundary layers at the horizontal container plates are essentially conducting and thus the fluid is motionless. Consequently, the average temperature exhibits a linear profile in the boundary layers. In this article, we rigorously investigate the average temperature and oscillations in the boundary layer via local bounds on the temperature field. Moreover, we deduce that the temperature profile is indeed essentially linear close to the horizontal container plates. Our results are uniform in the system parameters (e.g. the Rayleigh number) up to logarithmic correction terms. An important tool in our analysis is a new Hardy-type estimate for the convecting velocity field, which can be used to control the fluid motion in the layer. The bounds on the temperature field are derived with the help of local maximal regularity estimates for convection-diffusion equations.
Brunnian Braids Boundary Brunnian Braids Main Results Boundary Brunnian braids, mirror reflection
Wu, Jie
Brunnian Braids Boundary Brunnian Braids Main Results Boundary Brunnian braids, mirror reflection December 17, 2007 #12;Brunnian Braids Boundary Brunnian Braids Main Results Boundary Brunnian braids, mirror reflection and the homotopy groups Brunnian Braids Boundary Brunnian Braids Main Results #12
Quantum Brownian motion near a point-like reflecting boundary
V. A. De Lorenci; E. S. Moreira Jr.; M. M. Silva
2014-07-07
The Brownian motion of a test particle interacting with a quantum scalar field in the presence of a perfectly reflecting boundary is studied in (1 + 1)-dimensional flat spacetime. Particularly, the expressions for dispersions in velocity and position of the particle are explicitly derived and their behaviors examined. The results are similar to those corresponding to an electric charge interacting with a quantum electromagnetic field near a reflecting plane boundary, mainly regarding the divergent behavior of the dispersions at the origin (where the boundary is placed), and at the time interval corresponding to a round trip of a light pulse between the particle and the boundary. We close by addressing some effects of allowing the position of the particle to fluctuate.
Active Control of Plasma Boundaries Using Edge Currents
Budny, Robert
response and low power levels. - independent of vessel magnetic penetration time scales. · Useful boundaries using edge currents has been demonstrated in numerous experiments to produce edge conditions fields on a faster time scale and with less power than external magnetic field coils. - fast time
Laminar boundary layers in convective heat transport
Seis, Christian
2012-01-01
We study Rayleigh-Benard convection in the high-Rayleigh-number and high-Prandtl-number regime, i.e., we consider a fluid in a container that is exposed to strong heating of the bottom and cooling of the top plate in the absence of inertia effects. While the dynamics in the bulk are characterized by a chaotic convective heat flow, the boundary layers at the horizontal container plates are essentially conducting and thus the fluid is motionless. Consequently, the average temperature exhibits a linear profile in the boundary layers. In this article, we rigorously investigate the average temperature and oscillations in the boundary layer via local bounds on the temperature field. Moreover, we deduce that the temperature profile is indeed essentially linear close to the horizontal container plates. Our results are uniform in the system parameters (e.g. the Rayleigh number) up to logarithmic correction terms. An important tool in our analysis is a new Hardy-type estimate for the convecting velocity field, which ca...
Boundary Degeneracy of Topological Order
Juven Wang; Xiao-Gang Wen
2015-01-15
We introduce the concept of boundary degeneracy of topologically ordered states on a compact orientable spatial manifold with boundaries, and emphasize that the boundary degeneracy provides richer information than the bulk degeneracy. Beyond the bulk-edge correspondence, we find the ground state degeneracy of the fully gapped edge modes depends on boundary gapping conditions. By associating different types of boundary gapping conditions as different ways of particle or quasiparticle condensations on the boundary, we develop an analytic theory of gapped boundaries. By Chern-Simons theory, this allows us to derive the ground state degeneracy formula in terms of boundary gapping conditions, which encodes more than the fusion algebra of fractionalized quasiparticles. We apply our theory to Kitaev's toric code and Levin-Wen string-net models. We predict that the $Z_2$ toric code and $Z_2$ double-semion model (more generally, the $Z_k$ gauge theory and the $U(1)_k \\times U(1)_{-k}$ non-chiral fractional quantum Hall state at even integer $k$) can be numerically and experimentally distinguished, by measuring their boundary degeneracy on an annulus or a cylinder.
) Programs o Commercial PACE · The Los Angeles County PACE program offers funding for nonresidential solarCity of Palmdale This page outlines solar PV incentives, financing mechanisms, permitting process solar energy system for your home or business. o Typically solar installers will: Locate financing
) Programs o Commercial PACE · The Los Angeles County PACE program offers funding for nonresidential solarCity of Long Beach This page outlines solar PV incentives, financing mechanisms, permitting process;Find an Installer · Qualified contractors are your key to getting the most productive solar energy
) Programs o Commercial PACE · The Los Angeles County PACE program offers funding for nonresidential solarCity of Santa Monica This page outlines solar PV incentives, financing mechanisms, permitting contractors are your key to getting the most productive solar energy system for your home or business. o
BSc Biological Sciences Course Outline 1. Awarding institution The Royal Veterinary College
Daley, Monica A.
underpins an individual discipline or subject area. · Cognate sciences. · The political, social and economic1 BSc Biological Sciences Course Outline 1. Awarding institution The Royal Veterinary College 2. Final award Bachelor of Science 5. Programme Title Biological Sciences 6. Date of First Intake 2014 7
BSc Bioveterinary Sciences Course Outline 1. Awarding institution The Royal Veterinary College
Daley, Monica A.
an individual discipline or subject area. · Cognate sciences. · The political, social and economic context1 BSc Bioveterinary Sciences Course Outline 1. Awarding institution The Royal Veterinary College 2. Final award Bachelor of Science 5. Programme Title Bioveterinary Sciences 6. Date of First Intake 2002 7
COURSE OUTLINE PHYSICS 111 FALL 2009 PHYS 111 HOME PAGE: http://web.njit.edu/~opyrchal
COURSE OUTLINE PHYSICS 111 FALL 2009 PHYS 111 HOME PAGE: http://web.njit.edu/~opyrchal FACULTY: Halina Opyrchal: 454 Tiernan, opyrchal@adm.njit.edu, http://web.njit.edu/~opyrchal Haimin Wang: 460@adm.njit.edu, http://web.njit.edu/~fayngold Camelia Prodan: 480 Tiernan, cprodan@adm.njit.edu, http://web
Physics 171 General Relativity, Black Holes and Cosmology Fall 2014 Course Outline
California at Santa Cruz, University of
Physics 171 General Relativity, Black Holes and Cosmology Fall 2014 Course Outline Topic Reading 1. Introduction to Tensors Chapter 10 of Boas 2. Covariance of Physical Laws Chapter 2.1 3. Special Relativity. For an introduction to tensors, please review Chapter 10 of Mary L. Boas, Mathematical Methods in the Physical
Thompson, Michael
CHEMICAL ENGINEERING HANDBOOK 2015/16 #12;This Graduate Student Handbook outlines the policies and procedures followed by the Department of Chemical Engineering with respect to Graduate Studies. All students, which have been created with the Department of Chemical Engineering, are specified in this Handbook
OUTLINE OF DATA SOURCES, MAY 1933 LANDAREAS OCEAN AREAS SOURCES OF DATA
~ecldeallydv- en.but when Drmnt weather is rewrted: Base map descdptIon N used when coverage mbsing "round i#12;#12;#12;OUTLINE OF DATA SOURCES, MAY 1933 LANDAREAS OCEAN AREAS SOURCES OF DATA Area Bource National dfdeordogiguc dc Efance. 2 Daily Weather Report, Egypt. 3 Monthly Meteorological Bulletin, Nanking
James, L. Allan
Short Outline of Readings for Geog. 549 Chapter 1. Introduction - Watersheds and Water: Essential Resources PART ONE - ENVIRONMENTAL ASPECTS OF WATER RESOURCES Section I. Physical Hydrology Chapter 2. History of the Hydrologic Cycle and Water Properties (omitted) Chapter 3. Atmospheric Water and Global
Degree Requirements for Real Estate, Bachelor of Science Suggested Curriculum Outline
Hammack, Richard
Degree Requirements for Real Estate, Bachelor of Science Suggested Curriculum Outline Fall Semester of Argument 3 FIRE 305 Principles of Real Estate 3 Business General Education elective 3 SCMA 301 Business Marketing Principles 3 FIRE 325 Real Estate Law 3 SCMA 302 Business Statistics II 3 INFO 360 Business
COURSE OUTLINE FOR Elec Eng 4PL4 -Energy Systems and Management Academic
Haykin, Simon
Generation: different types of conventional power stations and related major plant; renewable sourcesCOURSE OUTLINE FOR Elec Eng 4PL4 - Energy Systems and Management Academic Year 2014-15; Term 1 to consumers, to the final supply and cost regimes for electrical energy. The design and performance of large
UMass Lowell MSA Curriculum outline Students with undergraduate non-accounting business degrees
Massachusetts at Lowell, University of
UMass Lowell MSA Curriculum outline Students with undergraduate non-accounting business degrees Credits Prerequisite undergraduate courses (5 courses required): 1 60.301 Intermediate Accounting I (60.202 Managerial Accounting) 3 60.302 Intermediate Accounting II (60.301 Intermediate Accounting I ) 3 60.321 Cost
5Health and Safety Policy General OutlineStatement of Responsibilities for Health and Safety
Haase, Markus
5Health and Safety Policy General OutlineStatement of Responsibilities for Health and Safety Every member of the University community has a responsibility to achieve good health and safety practice Statement (see p.4) which sets out the University's commitment to health and safety 2. as an identified set
Wireless LANs: outline wireless 802.11 and WiFi.
Biagioni, Edoardo S.
Wireless LANs: outline wireless 802.11 and WiFi. 802.11 security: WEP, 802.11i, WPA, WPA2. networking security wireless ad-hoc and mesh networks #12;ISM bands to operate most radios, a license availability of the 2.4GHz ISM band, many applications have been developed for it #12;Wireless 802.11/Wi
Applied Mathematics 4611F page 1 of 2 Course Outline 2011-12 Prof. Z. Krougly
Krougly, Zinovi
by Topical Areas: Basic C++, Fundamental Types and Basic Operators Functions, Recursion, Iteration in Physics, Biology, Finance and Environmental Science. Method of Evaluation: 5% Assignment 1 Â September 26 Outlines: The UWO Senate Academic Handbook has specified that the following points should be added to all
Applied Mathematics 4611F page 1 of 3 Course Outline 2014-15
Krougly, Zinovi
-Oriented Programming and C++ Basic C++, Fundamental Types and Basic Operators Functions, Recursion, Iteration Modeling, Environmental Science, etc. * is a combined undergraduate/graduate course #12;Applied Mathematics Course Outlines: The UWO Senate Academic Handbook has specified that the following points should be added
Stability of black holes in Einstein-charged scalar field theory in a cavity
Dolan, Sam R; Winstanley, Elizabeth
2015-01-01
Can a black hole that suffers a superradiant instability evolve towards a 'hairy' configuration which is stable? We address this question in the context of Einstein-charged scalar field theory. First, we describe a family of static black hole solutions which possess charged scalar-field hair confined within a mirror-like boundary. Next, we derive a set of equations which govern the linear, spherically symmetric perturbations of these hairy solutions. We present numerical evidence which suggests that, unlike the vacuum solutions, the (single-node) hairy solutions are stable under linear perturbations. Thus, it is plausible that stable hairy black holes represent the end-point of the superradiant instability of electrically-charged Reissner-Nordstrom black holes in a cavity; we outline ways to explore this hypothesis.
Logarithmic CFT on the Boundary and the World-Sheet
Alex Lewis
2000-09-12
The correspondences between logarithmic operators in the CFTs on the boundary of AdS_3 and on the world-sheet and dipole fields in the bulk are studied using the free field formulation of the SL(2,C)/SU(2) WZNW model. We find that logarithmic operators on the boundary are related to operators on the world-sheet which are in indecomposable representations of SL(2). The Knizhnik-Zamolodchikov equation is used to determine the conditions for those representations to appear in the operator product expansions of the model.
Geography 104 Boundary Layer Climates
Geography 104 Boundary Layer Climates Assignment #5 Question 1: The Urban Heat Island The following briefly how the use of giant windmills or fans can be effective in preventing frost in an orchard. Refer
Compressed Natural Gas (Rev 09/14) DRAFT Page 1 of 14 Examination Procedure Outline (EPO) for
EPO No. 28 Compressed Natural Gas (Rev 09/14) DRAFT Page 1 of 14 Examination Procedure Outline (EPO) for Compressed Natural Gas (CNG) Retail Motor-Fuel Dispensers It is recommended that this outline be followed as minimum criteria for examining retail motor-fuel dispensers used to measure compressed natural gas. Non
Seppäläinen, Timo
Outline Directed polymers Log-gamma polymer KPZ equation Fluctuation exponents for certain 1+1 dimensional directed polymers Timo Sepp¨al¨ainen Department of Mathematics University of Wisconsin-Madison MSRI December 2010 Fluctuation exponents for polymers 1/36 #12;Outline Directed polymers Log
Wind on the boundary for the Abelian sandpile model
Philippe Ruelle
2007-07-25
We continue our investigation of the two-dimensional Abelian sandpile model in terms of a logarithmic conformal field theory with central charge c=-2, by introducing two new boundary conditions. These have two unusual features: they carry an intrinsic orientation, and, more strangely, they cannot be imposed uniformly on a whole boundary (like the edge of a cylinder). They lead to seven new boundary condition changing fields, some of them being in highest weight representations (weights -1/8, 0 and 3/8), some others belonging to indecomposable representations with rank 2 Jordan cells (lowest weights 0 and 1). Their fusion algebra appears to be in full agreement with the fusion rules conjectured by Gaberdiel and Kausch.
Outlining the Local Void with the Parkes HI ZOA and Galactic Bulge Surveys
Renee C. Kraan-Korteweg; Nebiha Shafi; Baerbel Koribalski; Lister Staveley-Smith; Peter Buckland; Patricia A. Henning; Anthony P. Fairall
2007-10-09
The Parkes deep HI ZOA survey has been extended between 2002 and 2004 towards higher latitudes in the Galactic Bulge region. This area of extreme star crowding and high extinction levels remains impenetrable at any other waveband regime. Preliminary results of the 3 dimensional distribution based on the combined HI-surveys are presented. We focus on the extent and "content" of the Local Void as outlined by these HI surveys, followed by a preliminary discussion of the properties of the few galaxies detected in the Local Void.
Large-Scale Streamwise Turbulent Structures in Hypersonic Boundary Layers
English, Benjamin L.
2013-04-22
Prior research in the field of boundary layer turbulence has identified streamwise-elongated large-scale turbulence structures in both low speed compressible and high speed (M=2.0) flow. No experimental work has been done in any flow of M> or =3...
1997-04-01
This model curriculum outline was developed using a turbo-DACUM (Developing a Curriculum) process which utilizes practicing experts to undertake a comprehensive job and task analysis. The job and task analysis serves to establish current baseline data accurately and to improve both the process and the product of the job through constant and continuous improvement of training. The DACUM process is based on the following assumptions: (1) Expert workers are the best source for task analysis. (2) Any occupation can be described effectively in terms of tasks. (3) All tasks imply knowledge, skills, and attitudes/values. A DACUM panel, comprised of six experienced and knowledgeable technicians who are presently working in the field, was given an orientation to the DACUM process. The panel then identified, verified, and sequenced all the necessary job duty areas and tasks. The broad duty categories were rated according to relative importance and assigned percentage ratings in priority order. The panel then rated every task for each of the duties on a scale of 1 to 3. A rating of 3 indicates an {open_quotes}essential{close_quotes} task, a rating of 2 indicates an {open_quotes}important{close_quotes} task, and a rating of 1 indicates a {open_quotes}desirable{close_quotes} task.
Present status of the Bevalac and design outline of proposed medical accelerator
Gough, R.A.
1986-03-01
The Bevalac currently supports a strong and diverse program of scientific research with beams of relativistic heavy ions in the Biomedical and Nuclear Sciences. These programs utilize ions throughout the Periodic Table that range in energy from a few MeV to 2 GeV/nucleon, including radioactive secondary beams, such as neon-19. This paper first provides a brief overview of the Bevalac, its present operational status and the accelerator improvement program, followed by a rationale for the proposed construction of a hospital-based modern synchrotron dedicated to applications in Biomedicine, including the radiotherapeutic treatment of cancer and other human disorders. An outline of the proposed design for the new machine is given, including discussion of the design philosophy, a review of major accelerator components, and the expected performance and operating characteristics.
Data Management Plan (outline) The Data Management Plan (DMP to the funder's Data Policy and (2) how the investigator plans to manage the data should cover the following topics: 1. Information about the data · Describe
Batina, Lejla
: (Schaum's Outline of Theory and Problems of) Calculus. McGraw-Hill Companies, 1999, 578 p., ISBN rationale getallen Q) een deelverzameling van R waar tussen elk paar van punten uit D overaftelbaar veel
Study of interdomain boundary in diamagnetic domain structure in beryllium
Philip Lykov
2002-11-21
At low temperatures, in strong magnetic fields, the formation of a non-uniform magnetisation is possible in a single-crystal metal sample whose demagnetising factor along the field is close to unity. Namely, so-called Condon diamagnetic domain structure arises and disappears periodically with magnetic field. In this paper, the diamagnetic domain structure in beryllium single crystalis analysed. Directly, existence of diamagnetic domains in that sample was observed earlier by the muon spin precession (mSR) resonance peak splitting. A method is described that allows to calculate quantitative characteristics of the interdomain boundary using the muon histograms. The technique is based on the Marquardt minimisation procedure that has been modified in order to reduce the influence of noise on iterations convergence. Boundary volume fraction was calculated.
Miguel Alcubierre; Jose M. Torres
2014-11-06
We introduce a set of constraint preserving boundary conditions for the Baumgarte-Shapiro-Shibata-Nakamura (BSSN) formulation of the Einstein evolution equations in spherical symmetry, based on its hyperbolic structure. While the outgoing eigenfields are left to propagate freely off the numerical grid, boundary conditions are set to enforce that the incoming eigenfields don't introduce spurious reflections and, more importantly, that there are no fields introduced at the boundary that violate the constraint equations. In order to do this we adopt two different approaches to set boundary conditions for the extrinsic curvature, by expressing either the radial or the time derivative of its associated outgoing eigenfield in terms of the constraints. We find that these boundary conditions are very robust in practice, allowing us to perform long lasting evolutions that remain accurate and stable, and that converge to a solution that satisfies the constraints all the way to the boundary.
Higher-dimensional perfect fluids and empty singular boundaries
Ricardo E. Gamboa Saravi
2012-04-22
In order to find out whether empty singular boundaries can arise in higher dimensional Gravity, we study the solution of Einstein's equations consisting in a ($N+2$)-dimensional static and hyperplane symmetric perfect fluid satisfying the equation of state $\\rho=\\eta\\, p$, being $\\rho$ an arbitrary constant and $N\\geq2$. We show that this spacetime has some weird properties. In particular, in the case $\\eta>-1$, it has an empty (without matter) repulsive singular boundary. We also study the behavior of geodesics and the Cauchy problem for the propagation of massless scalar field in this spacetime. For $\\eta>1$, we find that only vertical null geodesics touch the boundary and bounce, and all of them start and finish at $z=\\infty$; whereas non-vertical null as well as all time-like ones are bounded between two planes determined by initial conditions. We obtain that the Cauchy problem for the propagation of a massless scalar field is well-posed and waves are completely reflected at the singularity, if we only demand the waves to have finite energy, although no boundary condition is required.
Building BoundariesTM Information for Parents
California at Santa Cruz, University of
Building BoundariesTM Information for Parents Even very young children can learn some skills of 2 #12;Building BoundariesTM: Information for Parents How to Recognize Warning Signs in Your Child
Boundary learning by optimization with topological constraints
Helmstaedter, Moritz N.
Recent studies have shown that machine learning can improve the accuracy of detecting object boundaries in images. In the standard approach, a boundary detector is trained by minimizing its pixel-level disagreement with ...
EE 141: Electromagnetic Field Theory Fall Semester 2014
Oughstun, Kurt
@cems.uvm.edu Catalog Description: Fundamentals of electromagnetic field theory; vector analy- sis; electricEE 141: Electromagnetic Field Theory Fall Semester 2014 MWF 4:05Â4:55 PM (Votey 207) & F 1 and magnetic fields, potential theory, boundary conditions and boundary value problems, Maxwell-Lorentz theory
EE 141: Electromagnetic Field Theory Fall Semester 2015
Oughstun, Kurt
@cems.uvm.edu Catalog Description: Fundamentals of electromagnetic field theory and applica- tions: vector analysisEE 141: Electromagnetic Field Theory Fall Semester 2015 MWF 3:30Â4:20 PM (Perkins 101) & F 2, electric and magnetic fields, potential theory, boundary con- ditions and boundary value problems
The gravity field and plate boundaries in Venezuela
Folinsbee, Robert Allin
1972-01-01
Free-air and simple Bouguer anomaly maps of the Venezuelan continental margin (from 60°W to 72°W and from 7°N to 13°N) are presented. The major features of the free-air map are: the large lows associated with the deep ...
Nenad Antonic & Kresimir Burazin Boundary operator from matrix field formulation
Burazin, Kresimir
of Zagreb University of Osijek Bijenicka cesta 30 Trg Ljudevita Gaja 6 Zagreb, Croatia Osijek, Croatia nenad
ARM - Field Campaign - 2013 Lower Atmospheric Boundary Layer Experiment
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach HomeA Better Anode Design to Improve4AJ01) (See22, 2012 [DataJulyMarch 27,5 Southern2
Boundary conformal field theory and tunneling of edge quasiparticles in
Office of Scientific and Technical Information (OSTI)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfate Reducing Bacteria (Technical Report) | SciTechReport)(TechnicalArticle) |
Rohrer, Gregory S.
Validating computed grain boundary energies in fcc metals using the grain boundary character. Since the GBCD is inversely related to the grain boundary energy distribution, it offers a useful metric for validating grain boundary energy calculations. Comparisons between the measured GBCD and calculated energies
The 1987 Federal field exercise: The DOE experience
Adler, M.V.; Gant, K.S.
1989-06-01
The second full-scale field exercise of the Federal Radiological Emergency Response Plan (FRERP) was held at the Zion Nuclear Power Station, Zion, Illinois, in June 1987. The exercise incorporated the annual compliance exercise for the Zion plant and involved the operating utility, Commonwealth Edison Company, the states of Illinois and Wisconsin, local governments, volunteer groups, and representatives from 12 federal agencies. The 3-day exercise was played from many locations in the Zion area; Springfield, Illinois; Madison, Wisconsin; and Washington, DC. Approximately 1000 people participated in the exercise, which used a scenario in which an accident at the plant resulted in the release of radioactive material outside the plant boundary. The US Department of Energy (DOE) had major responsibilities during the planning, playing, and critiquing of the exercise; these functions are outlined in the report. This document describes the DOE participation in the planning and response during the exercise. During a radiological emergency, the FRERP gives DOE the responsibility for coordinating the federal radiological monitoring and assessment activities in support of the states and the cognizant federal agency. At Zion, a self-sufficient Federal Radiological Monitoring and Assessment Center was established by DOE at a nearby fairground in which over 200 people from DOE, the two states, and other federal agencies participated. Before the field exercise, a tabletop exercise and a dry run were held for training purposes. 5 refs., 6 figs.
Course Outline and General Information Courses: THE DYNAMIC EARTH GEOL1340
Chakhmouradian, Anton
. Gravity. Earth's magnetic field. Heat flow. Ocean floor 2 & 18 Origin of the oceans. Sea floor and transportation. Types and rate of weathering. Origin and evolution of soils. Types of soils. Sedimentary rocks 9
On the outer boundary of the sunspot penumbra
B. Kalman
2002-02-06
Comparison of photographic observations and vector-magnetograph measurements demonstrate, that the outer boundary of the sunspot penumbra --even in complex sunspot groups-- closely follows the 0.075T isogauss line of the total value of the magnetic field, corresponding approximately to the equipartition value in the photosphere. Radio observations also show this feature. The thick penumbra model with interchange convection (Jahn and Schmidt, 1994) gives the best explanation of the penumbral structure.
AKARI IRC survey of the Large Magellanic Cloud: Outline of the survey and initial results
Yoshifusa Ita; Takashi Onaka; Daisuke Kato; Toshihiko Tanabe; Itsuki Sakon; Hidehiro Kaneda; Akiko Kawamura; Takashi Shimonishi; Takehiko Wada; Fumihiko Usui; Bon-Chul Koo; Mikako Matsuura; Hidenori Takahashi; Yoshikazu Nakada; Tetsuo Hasegawa; Motohide Tamura
2008-08-22
We observed an area of 10 deg^2 of the Large Magellanic Cloud using the Infrared Camera on board AKARI. The observations were carried out using five imaging filters (3, 7, 11, 15, and 24 micron) and a dispersion prism (2 -- 5 micron, $\\lambda / \\Delta\\lambda$ $\\sim$ 20) equipped in the IRC. This paper describes the outline of our survey project and presents some initial results using the imaging data that detected over 5.9x10^5 near-infrared and 6.4x10^4 mid-infrared point sources. The 10 $\\sigma$ detection limits of our survey are about 16.5, 14.0, 12.3, 10.8, and 9.2 in Vega-magnitude at 3, 7, 11, 15, and 24 micron, respectively. The 11 and 15 micron data, which are unique to AKARI IRC, allow us to construct color-magnitude diagrams that are useful to identify stars with circumstellar dust. We found a new sequence in the color-magnitude diagram, which is attributed to red giants with luminosity fainter than that of the tip of the first red giant branch. We suggest that this sequence is likely to be related to the broad emission feature of aluminium oxide at 11.5 micron. The 11 and 15 micron data also indicate that the ([11] - [15]) micron color of both oxygen-rich and carbon-rich red giants once becomes blue and then turns red again in the course of their evolution, probably due to the change in the flux ratio of the silicate or silicon carbide emission feature at 10 or 11.3 micron to the 15 micron flux.
DCC Case Study: Wide Field Astronomy Unit (WFAU)
Donnelly, Martin
2005-12-01
Case study on the Wide Field Astronomy Unit (WFAU), Edinburgh. Outlines data curation issues with which WFAU is involved, with an emphasis on interoperability. Particular regard is given to the transfer and reuse of ...
Grain boundaries in coated conductors
Weigand, Marcus
2010-07-06
,757 • Bibliography: 5,087 ix Publications and Conference Presentations This thesis led to the following publications: • M. Weigand, S. C. Speller, G. M. Hughes, N. A. Rutter, S. Lozano-Perez, C. R. M. Grovenor and J. H. Durrell: “Individual grain boundary properties... and overall performance of metal-organic deposition coated conductors ”, Phys. Rev. B 81, 174537 (2010) • R. Hühne, J. Eickemeyer, V. S. Sarma, A. Güth, T. Thersleff, J. Freudenberger, O. de Haas, M. Weigand, J. H. Durrell, L. Schultz and B. Holzapfel: “Ap...
Boundary Layer Cloud Turbulence Characteristics
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D B L O OLaura|BilayerBiomimeticBooks Are FunBorrowingBrungerBoundary
Carbon transport in the bottom boundary layer. Final report
Agrawal, Y.C.
1998-10-05
This report summarizes the activities and findings from a field experiment devised to estimate the rates and mechanisms of transport of carbon across the continental shelves. The specific site chosen for the experiment was the mid-Atlantic Bight, a region off the North Carolina coast. The experiment involved a large contingent of scientists from many institutions. The specific component of the program was the transport of carbon in the bottom boundary layer. The postulate mechanisms of transport of carbon in the bottom boundary layer are: resuspension and advection, downward deposition, and accumulation. The high turbulence levels in the bottom boundary layer require the understanding of the coupling between turbulence and bottom sediments. The specific issues addressed in the work reported here were: (a) What is the sediment response to forcing by currents and waves? (b) What is the turbulence climate in the bottom boundary layer at this site? and (c) What is the rate at which settling leads to carbon sequestering in bottom sediments at offshore sites?
OCN-GG 644 syllabus only.xls Sediment Geochemistry (OCN/GG 644) Course Outline --Spring 2015
OCN-GG 644 syllabus only.xls Sediment Geochemistry (OCN/GG 644) Course Outline -- Spring 2015 Date to be covered 14-Jan W 2 Components and Distribution of Marine Sediment Types 19-Jan M -- Holiday: MLK Day 21-Jan W 3 Physical Properties of Sediments, Sediment Accumulation Rates and Sediment Transport Processes
Turc, Catalin
EXAMPLE CURRICULUM OUTLINE FOR B.A. MAJOR IN ENVIRONMENTAL GEOLOGY For matriculants entering in odd) SOPHMORE (Even Years) EEPS 110, Physical Geology (3)b EEPS 119, Geology Laboratory (1) PHYS 115 Geology (3) c EEPS 391, Senior Project (2) STAT 201, Basic Statistics for Social and Life Sciences (3
Turc, Catalin
EXAMPLE CURRICULUM OUTLINE FOR B.A. MAJOR IN ENVIRONMENTAL GEOLOGY For matriculants entering Activities (0) SOPHMORE (odd years) EEPS 110, Physical Geology (3)b EEPS 119, Geology Laboratory (1) PHYS 115 of Biology (3) STAT 201, Basic Statistics for Social and Life Sciences (3) EEPS 220, Environmental Geology (3
Kirschner, Denise
Seat Belt Use Policy Objective Outline the policy regarding use of seat belt in University belt when operating a U-M vehicle. 2. Operators are also required to ensure that all occupants are adhering to the seat belt use laws when operating a U-M vehicle. 3. State of Michigan seat belt laws
4.3 Boundary integral equations
2010-10-18
62. CHAPTER 4. OBSTACLE SCATTERING. 4.3 Boundary integral equations. We introduce the equivalent sources for the Helmholtz equation and establish ...
Performance Boundaries in Nb3Sn Superconductors
Godeke, Arno
2006-01-01
Boundaries in Nb 3 Sn Superconductors – Berkeley, CABoundaries in Nb 3 Sn Superconductors – Berkeley, CABoundaries in Nb 3 Sn Superconductors Arno Godeke Berkeley,
MAGNETIC FIELD CONFINEMENT IN THE SOLAR CORONA. I. FORCE-FREE MAGNETIC FIELDS B. Fornberg,2
Fornberg, Bengt
MAGNETIC FIELD CONFINEMENT IN THE SOLAR CORONA. I. FORCE-FREE MAGNETIC FIELDS N. Flyer,1 B, plasma density and magnetic field. We present a hydromag- netic study of the self-confinement of magnetic Axisymmetric force-free magnetic fields external to a unit sphere are studied as solutions to boundary value
Metal precipitation at grain boundaries in silicon: Dependence on grain boundary character are combined to determine the dependence of metal silicide precipitate formation on grain boundary character and microstructure in multicrystalline silicon mc-Si . Metal silicide precipitate decoration is observed to increase
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.
2001 TRAFFIC ZONE BOUNDARIES Zone Numbers
Toronto, University of
2001 TRAFFIC ZONE BOUNDARIES Zone Numbers & Detailed Definitions #12;2001 TRAFFIC ZONE BOUNDARIES of Toronto Joint Program in Transportation January 2003 #12;PREFACE This report presents the 2001 traffic zone numbers by local municipalities in the 2001 TTS survey area. The second part presents detailed
Environmental boundaries to energy development
Trivelpiece, A.W.
1989-01-01
Public concern about the environment, health and safety consequences of energy technology has been growing steadily for more than two decades in the United States. This concern forms an important boundary condition as the United States seeks to develop a new National Energy Strategy. Furthermore, the international aspects of the energy/environment interface such as acid rain global climate change and stratospheric ozone depletion are very prominent in US thinking. In fact, the energy systems of the world are becoming more closely coupled environmentally and otherwise. Now where is this coupling more important than that between the industrialized and developing world; the choices made by each will have profound effects on the other. The development of energy technologies compatible with both economic growth and improving and sustaining environmental quality represents a major R D challenge to the US and USSR. Decision about adoption of new technology and R D priorities can be improved by better measurements of how energy sources and uses are changing throughout the world and better methods to project the potential consequences of these decisions. Such projection require understanding relative risks of alternating existing and evolving technologies. All of these R D areas, technology improvement energy system monitoring and projection and comparative risk assessment are the topics of this seminar. Progress in each may be enhanced by collaboration and cooperation between our two countries. 7 refs., 27 figs., 5 tabs.
Dyer, Bill
and demand in the U.S., with only part of the demand being met by U.S. production. Canola oil has achieved1 1 June 2011 A-1280 Canola Production Field Guide Canola Production Field Guide 2 2 Edited.....................................101 · Contributors to Canola Production Field Guide........102 · Resource Contact Information
Role of the basin boundary conditions in gravity wave turbulence
Luc Deike; Benjamin Miquel; Pablo Gutiérrez-Matus; Timothée Jamin; Benoit Semin; Michael Berhanu; Eric Falcon; Félicien Bonnefoy
2015-09-02
Gravity wave turbulence is studied experimentally in a large wave basin where irregular waves are generated unidirectionally. The role of the basin boundary conditions (absorbing or reflecting) and of the forcing properties are investigated. To that purpose, an absorbing sloping beach opposite to the wavemaker can be replaced by a reflecting vertical wall. We observe that the wave field properties depend strongly on these boundary conditions. Quasi-one dimensional field of nonlinear waves propagate before to be damped by the beach whereas a more multidirectional wave field is observed with the wall. In both cases, the wave spectrum scales as a frequency-power law with an exponent that increases continuously with the forcing amplitude up to a value close to -4, which is the value predicted by the weak turbulence theory. The physical mechanisms involved are probably different according to the boundary condition used, but cannot be easily discriminated with only temporal measurements. We have also studied freely decaying gravity wave turbulence in the closed basin. No self-similar decay of the spectrum is observed, whereas its Fourier modes decay first as a time power law due to nonlinear mechanisms, and then exponentially due to linear viscous damping. We estimate the linear, nonlinear and dissipative time scales to test the time scale separation that highlights the important role of a large scale Fourier mode. By estimation of the mean energy flux from the initial decay of wave energy, the Kolmogorov-Zakharov constant is evaluated and found to be compatible with a recent theoretical value.
Role of the basin boundary conditions in gravity wave turbulence
Luc Deike; Benjamin Miquel; Pablo Gutiérrez-Matus; Timothée Jamin; Benoit Semin; Sébastien Aumaitre; Michael Berhanu; Eric Falcon; Félicien BONNEFOY
2014-12-16
Gravity wave turbulence is studied experimentally in a large wave basin where irregular waves are generated unidirectionally. The role of the basin boundary conditions (absorbing or reflecting) and of the forcing properties are investigated. To that purpose, an absorbing sloping beach opposite to the wavemaker can be replaced by a reflecting vertical wall. We observe that the wave field properties depend strongly on these boundary conditions. Quasi-one dimensional field of nonlinear waves propagate before to be damped by the beach whereas a more multidirectional wave field is observed with the wall. In both cases, the wave spectrum scales as a frequency-power law with an exponent that increases continuously with the forcing amplitude up to a value close to -4, which is the value predicted by the weak turbulence theory. The physical mechanisms involved are probably different according to the boundary condition used, but cannot be easily discriminated with only temporal measurements. We have also studied freely decaying gravity wave turbulence in the closed basin. No self-similar decay of the spectrum is observed, whereas its Fourier modes decay first as a time power law due to nonlinear mechanisms, and then exponentially due to linear viscous damping. We estimate the linear, nonlinear and dissipative time scales to test the time scale separation that highlights the important role of a large scale Fourier mode. By estimation of the mean energy flux from the initial decay of wave energy, the Kolmogorov-Zakharov constant is evaluated and found to be compatible with a recent theoretical value.
Chihiro Matsui
2014-12-08
We derived the corresponding boundary condition on Fermi fields to the spin-1/2 Heisenberg chain with boundary magnetic fields. In order to obtain the correct boundary condition from the variation of the action at the edges, we carefully treat the oscillating terms which emerge as a result of the chiral decomposition of fermions and do not contribute to the bulk Lagrangian. The obtained result is checked by compared with the exact result derived from the Bethe ansatz, by considering the mode expansion of fermions on the light-cone coordinates. We also give the spin-wave interpretation to the emergence of boundary bound states.
Conformally covariant boundary correlation functions with a quantum group
Kalle Kytölä; Eveliina Peltola
2014-10-23
Particular boundary correlation functions of conformal field theory are needed to answer some questions related to random conformally invariant curves known as Schramm-Loewner evolutions (SLE). In this article, we introduce a correspondence and establish its fundamental properties, which are used in companion articles for explicitly solving two such problems. The correspondence associates Coulomb gas type integrals to vectors in a tensor product representation of a quantum group, a q-deformation of the Lie algebra sl2. We show that desired properties of the functions are guaranteed by natural representation theoretical properties of the vectors.
New Boundaries for the B-Model
Bergman, Aaron
2008-01-01
Witten couples the open topological B-model to a holomorphic vector bundle by adding to the boundary of the worldsheet a Wilson loop for an integrable connection on the bundle. Using the descent procedure for boundary vertex operators in this context, I generalize this construction to write a worldsheet coupling for a graded vector bundle with an integrable superconnection. I then compute the open string vertex operators between two such boundaries. A theorem of J. Block gives that this is equivalent to coupling the B-model to an arbitrary object in the derived category.
Convex Configurations In Free Boundary Problems
2002-10-30
The quantity ? > 0 has the meaning of 1/E with E the high activation energy in ...... regularity of solutions to phase transition problems, Annals of Math. 143 (1996) ...... The main objective of this appendix is to outline the main steps in the proof.
Edery, Ariel [Physics Department, Bishop's University, 2600 College Street, Sherbrooke, Quebec, J1M 0C8 (Canada); Kavli Institute for Theoretical Physics, University of California, Kohn Hall, Santa Barbara, California 93106 (United States); Graham, Noah [Kavli Institute for Theoretical Physics, University of California, Kohn Hall, Santa Barbara, California 93106 (United States); Department of Physics, Middlebury College, Middlebury, Vermont 05753 (United States); MacDonald, Ilana [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, Ontario, M5S 3H4 (Canada); Physics Department, Bishop's University, 2600 College Street, Sherbrooke, Quebec, J1M 0C8 (Canada)
2009-06-15
Under dimensional reduction, a system in D spacetime dimensions will not necessarily yield its D-1-dimensional analog version. Among other things, this result will depend on the boundary conditions and the dimension D of the system. We investigate this question for scalar and Abelian gauge fields under boundary conditions that obey the symmetries of the action. We apply our findings to the Casimir piston, an ideal system for detecting boundary effects. Our investigation is not limited to extra dimensions and we show that the original piston scenario proposed in 2004, a toy model involving a scalar field in 3D (2+1) dimensions, can be obtained via dimensional reduction from a more realistic 4D electromagnetic (EM) system. We show that for perfect conductor conditions, a D-dimensional EM field reduces to a D-1 scalar field and not its lower-dimensional version. For Dirichlet boundary conditions, no theory is recovered under dimensional reduction and the Casimir pressure goes to zero in any dimension. This ''zero Dirichlet'' result is useful for understanding the EM case. We then identify two special systems where the lower-dimensional version is recovered in any dimension: systems with perfect magnetic conductor (PMC) and Neumann boundary conditions. We show that these two boundary conditions can be obtained from a variational procedure in which the action vanishes outside the bounded region. The fields are free to vary on the surface and have zero modes, which survive after dimensional reduction.
Theory and Fluid Simulations of Boundary Plasma Fluctuations
Cohen, R H; LaBombard, B; LoDestro, L L; Rognlien, T D; Ryutov, D D; Terry, J L; Umansky, M V; Xu, X Q; Zweben, S
2007-01-09
Theoretical and computational investigations are presented of boundary plasma microturbulence that take into account important effects of the geometry of diverted tokamaks--in particular, the effect of x-point magnetic shear and the termination of field lines on divertor plates. We first generalize our previous 'heuristic boundary condition' which describes, in a lumped model, the closure of currents in the vicinity of the x-point region to encompass three current-closure mechanisms. We then use this boundary condition to derive the dispersion relation for low-beta flute-like modes in the divertor-leg region under the combined drives of curvature, sheath impedance, and divertor tilt effects. The results indicate the possibility of strongly growing instabilities, driven by sheath boundary conditions, and localized in either the private or common flux region of the divertor leg depending on the radial tilt of divertor plates. We re-visit the issue of x-point effects on blobs, examining the transition from blobs terminated by x-point shear to blobs that extend over both the main SOL and divertor legs. We find that, for a main-SOL blob, this transition occurs without a free-acceleration period as previously thought, with x-point termination conditions applying until the blob has expanded to reach the divertor plate. We also derive propagation speeds for divertor-leg blobs. Finally, we present fluid simulations of the C-Mod tokamak from the BOUT edge fluid turbulence code, which show main-SOL blob structures with similar spatial characteristics to those observed in the experiment, and also simulations which illustrate the possibility of fluctuations confined to divertor legs.
Hybrid immersed interface-immersed boundary methods for AC dielectrophoresis
Hossan, Mohammad Robiul [School of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164-2920 (United States); Department of Engineering and Physics, University of Central Oklahoma, Edmond, OK 73034-5209 (United States); Dillon, Robert [Department of Mathematics, Washington State University, Pullman, WA 99164-3113 (United States); Dutta, Prashanta, E-mail: dutta@mail.wsu.edu [School of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164-2920 (United States)
2014-08-01
Dielectrophoresis, a nonlinear electrokinetic transport mechanism, has become popular in many engineering applications including manipulation, characterization and actuation of biomaterials, particles and biological cells. In this paper, we present a hybrid immersed interface–immersed boundary method to study AC dielectrophoresis where an algorithm is developed to solve the complex Poisson equation using a real variable formulation. An immersed interface method is employed to obtain the AC electric field in a fluid media with suspended particles and an immersed boundary method is used for the fluid equations and particle transport. The convergence of the proposed algorithm as well as validation of the hybrid scheme with experimental results is presented. In this paper, the Maxwell stress tensor is used to calculate the dielectrophoretic force acting on particles by considering the physical effect of particles in the computational domain. Thus, this study eliminates the approximations used in point dipole methods for calculating dielectrophoretic force. A comparative study between Maxwell stress tensor and point dipole methods for computing dielectrophoretic forces are presented. The hybrid method is used to investigate the physics of dielectrophoresis in microfluidic devices using an AC electric field. The numerical results show that with proper design and appropriate selection of applied potential and frequency, global electric field minima can be obtained to facilitate multiple particle trapping by exploiting the mechanism of negative dielectrophoresis. Our numerical results also show that electrically neutral particles form a chain parallel to the applied electric field irrespective of their initial orientation when an AC electric field is applied. This proposed hybrid numerical scheme will help to better understand dielectrophoresis and to design and optimize microfluidic devices.
A FREE BOUNDARY PROBLEM ARISING FROM SEGREGATION ...
2013-06-18
In this work, we show how to obtain a free boundary problem as the limit of a fully non linear elliptic .... b) to find the solution for a optimal partition problem.
PRE-PRECIPITATION PHENOMENA AT GRAIN BOUNDARIES
Briceno-Valero, J.
2010-01-01
13820 DE82 0 1 2 7 9 4 PRE-PRECIPITATION PHENOMENA AT GRAINof any evidence suggesting precipitation has occurred. Theand grain boundary precipitation have shown (1) that there
Suppression of Grain Boundaries in Graphene Growth on Superstructured...
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Heat content asymptotics with transmittal and transmission boundary conditions
Peter Gilkey; Klaus Kirsten
2002-06-14
We study the heat content asymptotics on a Riemannian manifold with smoooth boundary defined by Dirichlet, Neumann, transmittal and transmission boundary conditions.
Singular perturbation problem in boundary/fractional combustion
2015-08-18
reaction-diffusion equation, where the reaction term is of combustion type. ... Free boundary problem, combustion theory, boundary reaction- diffusion, fractional ...
EA-1973: Kootenai River Restoration at Bonners Ferry, Boundary...
73: Kootenai River Restoration at Bonners Ferry, Boundary County, Idaho EA-1973: Kootenai River Restoration at Bonners Ferry, Boundary County, Idaho Summary Bonneville Power...
Technoeconomic Boundary Analysis of Biological Pathways to Hydrogen...
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Boundary Analysis of Biological Pathways to Hydrogen Production Technoeconomic Boundary Analysis of Biological Pathways to Hydrogen Production Report documenting the biological and...
Behaviour of boundary functions for quantum billiards
A. Bäcker; S. Fürstberger; R. Schubert; F. Steiner
2002-10-16
We study the behaviour of the normal derivative of eigenfunctions of the Helmholtz equation inside billiards with Dirichlet boundary condition. These boundary functions are of particular importance because they uniquely determine the eigenfunctions inside the billiard and also other physical quantities of interest. Therefore they form a reduced representation of the quantum system, analogous to the Poincar\\'e section of the classical system. For the normal derivatives we introduce an equivalent to the standard Green function and derive an integral equation on the boundary. Based on this integral equation we compute the first two terms of the mean asymptotic behaviour of the boundary functions for large energies. The first term is universal and independent of the shape of the billiard. The second one is proportional to the curvature of the boundary. The asymptotic behaviour is compared with numerical results for the stadium billiard, different limacon billiards and the circle billiard, and good agreement is found. Furthermore we derive an asymptotic completeness relation for the boundary functions.
A boundary integral formalism for stochastic ray tracing in billiards
David J. Chappell; Gregor Tanner
2014-11-06
Determining the flow of rays or particles driven by a force or velocity field is fundamental to modelling many physical processes, including weather forecasting and the simulation of molecular dynamics. High frequency wave energy distributions can also be approximated using flow or transport equations. Applications arise in underwater and room acoustics, vibro-acoustics, seismology, electromagnetics, quantum mechanics and in producing computer generated imagery. In many practical applications, the driving field is not known exactly and the dynamics are determined only up to a degree of uncertainty. This paper presents a boundary integral framework for propagating flows including uncertainties, which is shown to systematically interpolate between a deterministic and a completely random description of the trajectory propagation. A simple but efficient discretisation approach is applied to model uncertain billiard dynamics in an integrable rectangular domain.
Field_SWAT: A tool for mapping SWAT output to field boundaries Naresh Pai a
in the transformation of models from those that consider the entire catchment as a lumped unit to the contempor- ary, distributed models. The public availability of digital data such as digital elevation models (DEM), soils
Sea Oil Field Satellite Monitoring: An Opera3onal View
Kuligowski, Bob
:on alone contains 54% of the sea's oil reserves and 45% of its gasSea Oil Field Satellite Monitoring: An Opera3onal View Maurizio, Camp Springs, MD 20746 #12;Outline Introduc:on Sea oil fields Synthe:c Aperture
Electron Cyclotron Heating in a Non-Uniform Magnetic Field
Sprott, Julien Clinton
Electron Cyclotron Heating in a Non-Uniform Magnetic Field by J.e. Sprott December 1968 Presented with uniform or mirror magnetic fields. 2-4 Microwave heat ing in multipoles and other nonuniform magnetic will outline a simple theoretical model which can be used to estimate the electron cyclotron heating rate
Boundary Behavior of the GinzburgLandau Order Parameter in the Surface Superconductivity Regime
Recanati, Catherine
Boundary Behavior of the GinzburgLandau Order Parameter in the Surface Superconductivity Regime MLandau theory for a typeII superconductor in an applied magnetic field varying between the second and third of this energy expansion, which allows us to prove the desired uniformity of the surface superconductivity layer
Numerical solution of eddy current problems in bounded domains using realistic boundary
RodrÃguez, Rodolfo
Numerical solution of eddy current problems in bounded domains using realistic boundary conditions-called eddy currents. The problem is formulated in terms of the magnetic field. This formulation in a metallurgical arc furnace. Key words: low-frequency harmonic Maxwell equations, eddy current problems, finite
HOW TO DISPATCH OBSERVERS TO TRACK AN EVOLVING BOUNDARY Tingting Jiang and Carlo Tomasi
Tomasi, Carlo
it necessary to dispatch a limited number of observers (ships, vehicles, or air- planes with cameras; field boundary of a large phenomenon such as an oil spill, a fire, a hurricane, air or water pollution, or EL Ni. Water currents, temperatures, or pollution levels are recorded over vast areas by vessels or movable
Multiscale simulation of xenon diffusion and grain boundary segregation in UO?
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Andersson, David A.; Tonks, Michael R.; Casillas, Luis; Vyas, Shyam; Nerikar, Pankaj; Uberuaga, Blas P.; Stanek, Christopher R.
2015-07-01
In light water reactor fuel, gaseous fission products segregate to grain boundaries, resulting in the nucleation and growth of large intergranular fission gas bubbles. The segregation rate is controlled by diffusion of fission gas atoms through the grains and interaction with the boundaries. Based on the mechanisms established from earlier density functional theory (DFT) and empirical potential calculations, diffusion models for xenon (Xe), uranium (U) vacancies and U interstitials in UO? have been derived for both intrinsic (no irradiation) and irradiation conditions. Segregation of Xe to grain boundaries is described by combining the bulk diffusion model with a model formore »the interaction between Xe atoms and three different grain boundaries in UO? (?5 tilt, ?5 twist and a high angle random boundary), as derived from atomistic calculations. The present model does not attempt to capture nucleation or growth of fission gas bubbles at the grain boundaries. The point defect and Xe diffusion and segregation models are implemented in the MARMOT phase field code, which is used to calculate effective Xe and U diffusivities as well as to simulate Xe redistribution for a few simple microstructures.« less
Confined quantum fields under the influence of a uniform magnetic field
E. Elizalde; F. C. Santos; A. C. Tort
2002-07-10
We investigate the influence of a uniform magnetic field on the zero-point energy of charged fields of two types, namely, a massive charged scalar field under Dirichlet boundary conditions and a massive fermion field under MIT boundary conditions. For the first, exact results are obtained, in terms of exponentially convergent functions, and for the second, the limits for small and for large mass are analytically obtained too. Coincidence with previously known, partial result serves as a check of the procedure. For the general case in the second situation --a rather involved one-- a precise numerical analysis is performed.
Green's function for a n-dimensional closed, static universe and with a spherical boundary
Mustafa Ozcan
2001-06-26
We construct the Hadamard Green's function by using the eigenfunction, which are obtained by solving the wave equation for the massless conformal scalar field on the S^n-1 of a n-dimensional closed, static universe. We also consider the half space case with both the Dirichlet and the Neumann boundary conditions. Solving of eigenfunction and eigenvalues of the corresponding field equation is interesting since the Casimir energy could be calculated analytically by various methods.
E ective boundary conditions for laminar ows over periodic rough boundaries
Achdou, Yves
E#27;ective boundary conditions for laminar #29;ows over periodic rough boundaries Yves Achdou #3 are proposed for a laminar #29;ow over a rough wall with periodic roughness elements. These e#27;ective is such an approach ? In this paper, we wish to answer these questions for laminar #29;ows over periodic rough walls
Barmak, Katayun [Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027 and Department of Materials Science and Engineering and Materials Research Science and Engineering Center, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213 (United States); Darbal, Amith [Department of Materials Science and Engineering and Materials Research Science and Engineering Center, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213 (United States); Ganesh, Kameswaran J.; Ferreira, Paulo J. [Materials Science and Engineering, The University of Texas at Austin, 1 University Station, Austin, Texas 78712 (United States); Rickman, Jeffrey M. [Department of Materials Science and Engineering and Department of Physics, Lehigh University, Bethlehem, Pennsylvania 18015 (United States); Sun, Tik; Yao, Bo; Warren, Andrew P.; Coffey, Kevin R., E-mail: kb2612@columbia.edu [Department of Materials Science and Engineering, University of Central Florida, 4000 Central Florida Boulevard, Orlando, Florida 32816 (United States)
2014-11-01
The relative contributions of various defects to the measured resistivity in nanocrystalline Cu were investigated, including a quantitative account of twin-boundary scattering. It has been difficult to quantitatively assess the impact twin boundary scattering has on the classical size effect of electrical resistivity, due to limitations in characterizing twin boundaries in nanocrystalline Cu. In this study, crystal orientation maps of nanocrystalline Cu films were obtained via precession-assisted electron diffraction in the transmission electron microscope. These orientation images were used to characterize grain boundaries and to measure the average grain size of a microstructure, with and without considering twin boundaries. The results of these studies indicate that the contribution from grain-boundary scattering is the dominant factor (as compared to surface scattering) leading to enhanced resistivity. The resistivity data can be well-described by the combined Fuchs–Sondheimer surface scattering model and Mayadas–Shatzkes grain-boundary scattering model using Matthiessen's rule with a surface specularity coefficient of p?=?0.48 and a grain-boundary reflection coefficient of R?=?0.26.
Contract Management Plan Outline
of all necessary actions for effective contracting, ensuring compliance with the terms of the contract, and safeguarding the interests of the United States in its...
Process Metallurgy Course Outline
New South Wales, University of
-6 8 Reactor design 6 Midsession exam Week 6-7 8 Blast furnace ironmaking 7-8 Assignment 9 Reactions in the blast furnace 9 10 Development of the blast furnace ironmaking to decrease carbon footprint 9 11 Alternative ironmaking processes 10 12 Steelmaking: Bessemer and BOS processes, Electric arc furnace 10-11 13
COURSE OUTLINE Stochastic Processes
Smith, Robert L.
; the Poisson process; renewal theory; Markov chains; and some continuous state models including Brownian motion.umich.edu COURSE DESCRIPTION: This is a basic course in stochastic processes with emphasis on model building to Probability Models, Academic Press, latest. REFERENCES: Cinlar, E., Introduction to Stochastic Processes
Lecture outline Classification
Terzi, Evimaria
;Naïve Bayes Classifier: Example · X' = (HomeOwner = No, MaritalStatus = Married, Income=120K) · Need on training data · Test phase: For test record X', compute the class Y' that maximizes the posterior probability Pr(Y'|X') Wednesday, October 30, 13 #12;Bayes Classification: Example X'=(Home Owner=No, Marital
Lecture outline Classification
Terzi, Evimaria
Classification: Example X'=(Home Owner=No, Marital Status=Married, AnnualIncome=120K) Compute: Pr(Yes|X'), Pr discretize? #12;Naïve Bayes Classifier: Example · X' = (HomeOwner = No, MaritalStatus = Married, Income=120K: For test record X', compute the class Y' that maximizes the posterior probability Pr(Y'|X') #12;Bayes
Process Metallurgy Course Outline
New South Wales, University of
................................................................................................... 7 Course Objective To develop an understanding of principles of metallurgical processes, reactor-mixed reactors. Tracer additions. Chemical performance of a metallurgical reactor. Principles of metallurgical of metallurgical reactors, batch and continuous, plug flow and well-mixed ideal reactors. Tracer additions. 4 6
User
2015-05-04
25.1 Counting Units Fast: circumference, area, and surface area formulas. 29. 25.2 Measurement of Area and Volume volume formulas. 30. 26.1 Special Topics
: An introduction to plasma physics and magnetohydrodynamics for advanced graduate students. Applications to Solar, Holland Frances F. Chen Introduction to Plasma Physics 1984, Plenum, New York Week 1: Review of Solar Physics Priest Chapter 1 Week 2: Introduction Chen Chapters 1, 2 and 7 --Plasma Parameters --Single
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a COTS solution existed, and that it would be relatively simple to install compared to building a system in-house. Other transmission utilities had purchased COTS software for...
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AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservationBio-Inspired SolarAboutXu Named|Got Solitons? SUpdated: 04/20/10Instantiating apftp
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AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservationBio-Inspired SolarAboutXu Named|Got Solitons? SUpdated: 04/20/10Instantiating apftp
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AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservationBio-Inspired SolarAboutXu Named|Got Solitons? SUpdated: 04/20/10Instantiating apftp
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AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservationBio-Inspired SolarAboutXu Named|Got Solitons? SUpdated: 04/20/10Instantiating apftp
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust, High-Throughput Analysis of Protein Structures PrintRooftop DiagnosticianRoomWPSS Root
Office of Scientific and Technical Information (OSTI)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield MunicipalTechnical Report:Speeding accessby aLED Street LightingFrom theHighI _ _1motion in
Wireless boundary monitor system and method
Haynes, Howard D. (Knoxville, TN); Ayers, Curtis W. (Kingston, TN)
1997-01-01
A wireless boundary monitor system used to monitor the integrity of a boundary surrounding an area uses at least two housings having at least one transmitting means for emitting ultrasonic pressure waves to a medium. Each of the housings has a plurality of receiving means for sensing the pressure waves in the medium. The transmitting means and the receiving means of each housing are aimable and communicably linked. At least one of the housings is equipped with a local alarm means for emitting a first alarm indication whereby, when the pressure waves propagating from a transmitting means to a receiving means are sufficiently blocked by an object a local alarm means or a remote alarm means or a combination thereof emit respective alarm indications. The system may be reset either manually or automatically. This wireless boundary monitor system has useful applications in both indoor and outdoor environments.
Wireless boundary monitor system and method
Haynes, H.D.; Ayers, C.W.
1997-12-09
A wireless boundary monitor system used to monitor the integrity of a boundary surrounding an area uses at least two housings having at least one transmitting means for emitting ultrasonic pressure waves to a medium. Each of the housings has a plurality of receiving means for sensing the pressure waves in the medium. The transmitting means and the receiving means of each housing are aimable and communicably linked. At least one of the housings is equipped with a local alarm means for emitting a first alarm indication whereby, when the pressure waves propagating from a transmitting means to a receiving means are sufficiently blocked by an object a local alarm means or a remote alarm means or a combination thereof emit respective alarm indications. The system may be reset either manually or automatically. This wireless boundary monitor system has useful applications in both indoor and outdoor environments. 4 figs.
Confining quantum particles with a purely magnetic field
Yves Colin De Verdière; Francoise Truc
2009-10-15
We consider an open domain with a compact boundary in an Euclidean space and a Schroedinger operator with magnetic field on this domain. We give sufficient conditions on the rate of growth of the magnetic field near the boundary which guarantees essential self-adjointness of this operator. From the physical point of view, it means that the quantum particle is confined in the domain by the magnetic field. We construct examples on polytopes and domains with smooth boundaries; these examples of "magnetic bottles" are highly simplified models of what is done for nuclear fusion in tokamacs.
Resonant transitions due to changing boundaries
F. Anzà; A. Messina; B. Militello
2015-01-10
The problem of a particle confined in a box with moving walls is studied, focusing on the case of small perturbations which do not alter the shape of the boundary (\\lq pantography\\rq). The presence of resonant transitions involving the natural transition frequencies of the system and the Fourier transform of the velocity of the walls of the box is brought to the light. The special case of a pantographic change of a circular box is analyzed in dept, also bringing to light the fact that the movement of the boundary cannot affect the angular momentum of the particle.
Fermionic Casimir Effect on the Topological Insulator Boundary
Muniz, C R
2014-01-01
In this paper we study the Casimir effect on the conducting surface of a topological insulator characterized by both $Z_2$ topological index and time reversal symmetry, subject to the action of a static and spatially homogeneous magnetic field perpendicular to that surface, at zero temperature. To do this, we consider modifications in the Gauss' law that arise due to the nonzero gradient of the axion-like pseudoscalar factor coupled to the constant magnetic field, which occur in a term that must be added to the electromagnetic Lagrangian in order to account for the topological properties of the system. Such term allows to find an effective point-like charge that changes the quantum vacuum of a spinor field in 1+2 dimensions confined on the edge under analysis. Since that the Casimir energy found depends on a length defined on the boundary, we show that there is a tangential density of force or a shear stress associated to the surface, tending to shrink or stretch it depending on the magnetic field direction. ...
Early-time free-surface flow driven by a deforming boundary
Brasz, C. Frederik; Arnold, Craig B.; Stone, Howard A.; Lister, John R.
2015-02-24
.6). The flow is driven by the boundary deformation, hb(x, t), given in (2.2). In partic- ular, we are interested in the velocity field and free-surface motion as the solid boundary approaches a steady state. 2.1. Nondimensionalization We nondimensionalize... . The axisymmetric domain-perturbation results showed similarly good agreement with simulations at ? = 0.05 and t = 20 across all values of ?; for brevity, these are not included here. The total kinetic energy in the axisymmetric simulations at t = 20 and ? = 0...
The effect of reconnection on the structure of the Sun's open-closed-flux boundary
Pontin, D I
2015-01-01
Global magnetic field extrapolations are now revealing the huge complexity of the Sun's corona, and in particular the structure of the boundary between open and closed magnetic flux. Moreover, recent developments indicate that magnetic reconnection in the corona likely occurs in highly fragmented current layers, and that this typically leads to a dramatic increase in the topological complexity beyond that of the equilibrium field. In this paper we investigate the consequences of reconnection at the open-closed flux boundary ("interchange reconnection") in a fragmented current layer. We demonstrate that it leads to a situation in which magnetic flux (and therefore plasma) from open and closed field regions is efficiently mixed together. This corresponds to an increase in the length and complexity of the open-closed boundary. Thus, whenever reconnection occurs at a null point or separator of the open-closed boundary, the associated separatrix arc of the so-called "S-web" in the high corona becomes not a single ...
Planetary Boundary Layer from AERI and MPL
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Sawyer, Virginia
The distribution and transport of aerosol emitted to the lower troposphere is governed by the height of the planetary boundary layer (PBL), which limits the dilution of pollutants and influences boundary-layer convection. Because radiative heating and cooling of the surface strongly affect the PBL top height, it follows diurnal and seasonal cycles and may vary by hundreds of meters over a 24-hour period. The cap the PBL imposes on low-level aerosol transport makes aerosol concentration an effective proxy for PBL height: the top of the PBL is marked by a rapid transition from polluted, well-mixed boundary-layer air to the cleaner, more stratified free troposphere. Micropulse lidar (MPL) can provide much higher temporal resolution than radiosonde and better vertical resolution than infrared spectrometer (AERI), but PBL heights from all three instruments at the ARM SGP site are compared to one another for validation. If there is agreement among them, the higher-resolution remote sensing-derived PBL heights can accurately fill in the gaps left by the low frequency of radiosonde launches, and thus improve model parameterizations and our understanding of boundary-layer processes.
Planetary Boundary Layer from AERI and MPL
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Sawyer, Virginia
2014-02-13
The distribution and transport of aerosol emitted to the lower troposphere is governed by the height of the planetary boundary layer (PBL), which limits the dilution of pollutants and influences boundary-layer convection. Because radiative heating and cooling of the surface strongly affect the PBL top height, it follows diurnal and seasonal cycles and may vary by hundreds of meters over a 24-hour period. The cap the PBL imposes on low-level aerosol transport makes aerosol concentration an effective proxy for PBL height: the top of the PBL is marked by a rapid transition from polluted, well-mixed boundary-layer air to the cleaner, more stratified free troposphere. Micropulse lidar (MPL) can provide much higher temporal resolution than radiosonde and better vertical resolution than infrared spectrometer (AERI), but PBL heights from all three instruments at the ARM SGP site are compared to one another for validation. If there is agreement among them, the higher-resolution remote sensing-derived PBL heights can accurately fill in the gaps left by the low frequency of radiosonde launches, and thus improve model parameterizations and our understanding of boundary-layer processes.
Determining environmental boundaries: asynchronous communication and physical
Ferguson, Thomas S.
to cooperatively locate the boundary of a given environmental function in two space dimensions using a combi this substitution is successfully taking place are de-mining operations [7], military urban operations [20 [23], or energy-minimizing curve. This process simulates elastic material which can dynamically
Origin of morphotropic phase boundaries in ferroelectrics
Wu, Zhigang
, Peter Liermann3 & Zhigang Wu4 A piezoelectric material is one that generates a voltage in response to a mechanical strain (and vice versa). The most useful piezo- electric materials display a transition region boundary under pressure. The results are consistent with first- principles theoretical predictions3
Thick diffusion limit boundary layer test problems
Bailey, T. S.; Warsa, J. S.; Chang, J. H.; Adams, M. L.
2013-07-01
We develop two simple test problems that quantify the behavior of computational transport solutions in the presence of boundary layers that are not resolved by the spatial grid. In particular we study the quantitative effects of 'contamination' terms that, according to previous asymptotic analyses, may have a detrimental effect on the solutions obtained by both discontinuous finite element (DFEM) and characteristic-method (CM) spatial discretizations, at least for boundary layers caused by azimuthally asymmetric incident intensities. Few numerical results have illustrated the effects of this contamination, and none have quantified it to our knowledge. Our test problems use leading-order analytic solutions that should be equal to zero in the problem interior, which means the observed interior solution is the error introduced by the contamination terms. Results from DFEM solutions demonstrate that the contamination terms can cause error propagation into the problem interior for both orthogonal and non-orthogonal grids, and that this error is much worse for non-orthogonal grids. This behavior is consistent with the predictions of previous analyses. We conclude that these boundary layer test problems and their variants are useful tools for the study of errors that are introduced by unresolved boundary layers in diffusive transport problems. (authors)
The Importance of Carbon Footprint Estimation Boundaries
Kammen, Daniel M.
The Importance of Carbon Footprint Estimation Boundaries H . S C O T T M A T T H E W S , C H R I and organizations are pursuing "carbon footprint" projects to estimate their own contributions to global climate change. Protocol definitions from carbon registries help organizations analyze their footprints
Vortex rings impinging on permeable boundaries
Mujal-Colilles, Anna; Dalziel, Stuart B.; Bateman, Allen
2015-01-17
of the boundary layer inside 548 the porous media or the flux exchange between the downstream and upstream sides of the 549 grid. 550 Recalling that one of the main differences between our experiments and the thin grid 551 research already published...
Lateral boundary errors in regional numerical weather
?umer, Slobodan
Lateral boundary errors in regional numerical weather prediction models Author: Ana Car Advisor, they describe evolution of atmospher - weather forecast. Every NWP model solves the same system of equations (1: assoc. prof. dr. Nedjeljka Zagar January 5, 2015 Abstract Regional models are used in many national
Accuracy Requirements for Rural Land Parcel Boundaries
Stock, Kristin
Accuracy Requirements for Rural Land Parcel Boundaries Kristin M. Stock School of Planning accuracy of about +/-0.2m. Utilities companies and local authorities in rural areas have more relaxed of Planning, Landscape Architecture and Surveying at Queensland University of Technology, and the Geodetic
1. Integrated Database 2. Boundary Analysis
of research? Data storage needs Meta data: legacy information Data processing diagrams Pastures Ecological that change in response to these processes Key processes that act as "drivers" of the system Key ecosystem of physical, ecological, social, and political boundaries using geographic information system Hypothesis 2
Title: Ontario Greenbelt Boundary File Data Creator /
Title: Ontario Greenbelt Boundary File Data Creator / Copyright Owner: Ontario Ministry of Municipal Affairs and Housing Publisher: Ontario Ministry of Municipal Affairs and Housing Edition: N/A Versions: N/A Publication Date: N/A Coverage Date(s): N/A Updates: N/A Abstract: The Ontario Greenbelt
Differential-Equation Based Absorbing Boundary Conditions
Schneider, John B.
Chapter 6 Differential-Equation Based Absorbing Boundary Conditions 6.1 Introduction A simple in the analysis of a wide range of FDTD-related topics. 6.2 The Advection Equation The wave equation that governs.2) The second form represents the equation in terms of an operator operating on Ez where the operator
Distributed Boundary Estimation using Sensor Networks
Ramamritham, Krithi
where such boundaries need to be detected include monitoring the spread of toxic gases [1], oil spills in oceans [2], or even tracking storm cloud front. Oil companies are interested in deploying off-shore sensor networks to monitor the area where oil spills normally happen. The focus in these cases
TRACKING DYNAMIC BOUNDARIES BY EVOLVING Tingting Jiang
Tingting Jiang
TRACKING DYNAMIC BOUNDARIES BY EVOLVING CURVES by Tingting Jiang Department of Computer Science Duke University Date: Approved: Carlo Tomasi, Supervisor Ron Parr Scott C. Schmidler Xiaobai Sun in the Department of Computer Science in the Graduate School of Duke University 2007 #12;ABSTRACT TRACKING DYNAMIC
Elementary Differential Equations with Boundary Value Problems
William F. Trench
2014-02-24
Dec 1, 2013 ... For more information, please contact jcostanz@trinity.edu. ..... (Laplace's Equation), the functions defining the boundary conditions on a given side of the rectangular .... change in heat of the object as its temperature changes from T0 to T is a(T ...... Let y be the angle measured from the rest position (vertically ...
Optimized boundary driven flows for dynamos in a sphere
Khalzov, I. V.; Brown, B. P.; Cooper, C. M.; Weisberg, D. B.; Forest, C. B. [Center for Magnetic Self Organization in Laboratory and Astrophysical Plasmas, University of Wisconsin-Madison, 1150 University Avenue, Madison, Wisconsin 53706 (United States)
2012-11-15
We perform numerical optimization of the axisymmetric flows in a sphere to minimize the critical magnetic Reynolds number Rm{sub cr} required for dynamo onset. The optimization is done for the class of laminar incompressible flows of von Karman type satisfying the steady-state Navier-Stokes equation. Such flows are determined by equatorially antisymmetric profiles of driving azimuthal (toroidal) velocity specified at the spherical boundary. The model is relevant to the Madison plasma dynamo experiment, whose spherical boundary is capable of differential driving of plasma in the azimuthal direction. We show that the dynamo onset in this system depends strongly on details of the driving velocity profile and the fluid Reynolds number Re. It is found that the overall lowest Rm{sub cr} Almost-Equal-To 200 is achieved at Re Almost-Equal-To 240 for the flow, which is hydrodynamically marginally stable. We also show that the optimized flows can sustain dynamos only in the range Rm{sub cr}
Mixing at the external boundary of a submerged turbulent jet
A. Eidelman; T. Elperin; N. Kleeorin; G. Hazak; I. Rogachevskii; O. Sadot; I. Sapir-Katiraie
2009-05-11
We study experimentally and theoretically mixing at the external boundary of a submerged turbulent jet. In the experimental study we use Particle Image Velocimetry and an Image Processing Technique based on the analysis of the intensity of the Mie scattering to determine the spatial distribution of tracer particles. An air jet is seeded with the incense smoke particles which are characterized by large Schmidt number and small Stokes number. We determine the spatial distributions of the jet fluid characterized by a high concentration of the particles and of the ambient fluid characterized by a low concentration of the tracer particles. In the data analysis we use two approaches, whereby one approach is based on the measured phase function for the study of the mixed state of two fluids. The other approach is based on the analysis of the two-point second-order correlation function of the particle number density fluctuations generated by tangling of the gradient of the mean particle number density by the turbulent velocity field. This gradient is formed at the external boundary of a submerged turbulent jet. We demonstrate that PDF of the phase function of a jet fluid penetrating into an external flow and the two-point second-order correlation function of the particle number density do not have universal scaling and cannot be described by a power-law function. The theoretical predictions made in this study are in a qualitative agreement with the obtained experimental results.
Multiscale molecular dynamics using the matched interface and boundary method
Geng Weihua [Department of Mathematics, Michigan State University, East Lansing, MI 48824 (United States); Wei, G.W., E-mail: wei@math.msu.ed [Department of Mathematics, Michigan State University, East Lansing, MI 48824 (United States); Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI 48824 (United States)
2011-01-20
The Poisson-Boltzmann (PB) equation is an established multiscale model for electrostatic analysis of biomolecules and other dielectric systems. PB based molecular dynamics (MD) approach has a potential to tackle large biological systems. Obstacles that hinder the current development of PB based MD methods are concerns in accuracy, stability, efficiency and reliability. The presence of complex solvent-solute interface, geometric singularities and charge singularities leads to challenges in the numerical solution of the PB equation and electrostatic force evaluation in PB based MD methods. Recently, the matched interface and boundary (MIB) method has been utilized to develop the first second order accurate PB solver that is numerically stable in dealing with discontinuous dielectric coefficients, complex geometric singularities and singular source charges. The present work develops the PB based MD approach using the MIB method. New formulation of electrostatic forces is derived to allow the use of sharp molecular surfaces. Accurate reaction field forces are obtained by directly differentiating the electrostatic potential. Dielectric boundary forces are evaluated at the solvent-solute interface using an accurate Cartesian-grid surface integration method. The electrostatic forces located at reentrant surfaces are appropriately assigned to related atoms. Extensive numerical tests are carried out to validate the accuracy and stability of the present electrostatic force calculation. The new PB based MD method is implemented in conjunction with the AMBER package. MIB based MD simulations of biomolecules are demonstrated via a few example systems.
Boundary Behavior of the Ginzburg-Landau Order Parameter in the Surface Superconductivity Regime
M. Correggi; N. Rougerie
2015-01-27
We study the 2D Ginzburg-Landau theory for a type-II superconductor in an applied magnetic field varying between the second and third critical value. In this regime the order parameter minimizing the GL energy is concentrated along the boundary of the sample and is well approximated to leading order by a simplified 1D profile in the direction perpendicular to the boundary. Motivated by a conjecture of Xing-Bin Pan, we address the question of whether this approximation can hold uniformly in the boundary region. We prove that this is indeed the case as a corollary of a refined, second order energy expansion including contributions due to the curvature of the sample. Local variations of the GL order parameter are controlled by the second order term of this energy expansion, which allows us to prove the desired uniformity of the surface superconductivity layer.
Zhang, Hao; Trias, F Xavier; Yu, Aibing; Tan, Yuanqiang; Oliva, Assensi
2015-01-01
In our recent work [H. Zhang, F.X. Trias, A. Oliva, D. Yang, Y. Tan, Y. Sheng. PIBM: Particulate immersed boundary method for fluid-particle interaction problems. Powder Technology. 272(2015), 1-13.], a particulate immersed boundary method (PIBM) for simulating fluid-particle multiphase flow was proposed and assessed in both two- and three-dimensional applications. In this study, the PIBM was extended to solve thermal interaction problems between spherical particles and fluid. The Lattice Boltzmann Method (LBM) was adopted to solve the fluid flow and temperature fields, the PIBM was responsible for the non-slip velocity and temperature boundary conditions at the particle surface, and the kinematics and trajectory of the solid particles were evaluated by the Discrete Element Method (DEM). Four case studies were implemented to demonstrate the capability of the current coupling scheme. Firstly, numerical simulation of natural convection in a two-dimensional square cavity with an isothermal concentric annulus was...
Thermodynamics of Blue Phases In Electric Fields
O. Henrich; D. Marenduzzo; K. Stratford; M. E. Cates
2010-03-04
We present extensive numerical studies to determine the phase diagrams of cubic and hexagonal blue phases in an electric field. We confirm the earlier prediction that hexagonal phases, both 2 and 3 dimensional, are stabilized by a field, but we significantly refine the phase boundaries, which were previously estimated by means of a semi-analytical approximation. In particular, our simulations show that the blue phase I -- blue phase II transition at fixed chirality is largely unaffected by electric field, as observed experimentally.
THE HELIOTAIL REVEALED BY THE INTERSTELLAR BOUNDARY EXPLORER
McComas, D. J.; Dayeh, M. A.; Livadiotis, G.; Funsten, H. O.; Schwadron, N. A.
2013-07-10
Recent combined observations from the first three years of Interstellar Boundary Explorer (IBEX) data allow us to examine the heliosphere's downwind region-the heliotail-for the first time. In contrast to a preliminary identification of a narrow ''offset heliotail'' structure, we find a broad slow solar wind plasma sheet crossing essentially the entire downwind side of the heliosphere at low to mid-latitudes, with fast wind tail regions to the north and south. The slow wind plasma sheet exhibits the steepest ENA spectra in the IBEX sky maps, appears as a two-lobed structure (lobes on the port and starboard sides), and is twisted in the sense of (but at a smaller angle than) the external magnetic field. The overall heliotail structure clearly demonstrates the intermediate nature of the heliosphere's interstellar interaction, where both the external dynamic and magnetic pressures strongly affect the heliosphere.
Boundary integral formulation for interfacial cracks in thermodiffusive bimaterials
L. Morini; A. Piccolroaz
2015-04-29
An original boundary integral formulation is proposed for the problem of a semi-infinite crack at the interface between two dissimilar elastic materials in the presence of heat flows and mass diffusion. Symmetric and skew-symmetric weight function matrices are used together with a generalized Betti's reciprocity theorem in order to derive a system of integral equations that relate the applied loading, the temperature and mass concentration fields, the heat and mass fluxes on the fracture surfaces and the resulting crack opening. The obtained integral identities can have many relevant applications, such as for the modelling of crack and damage processes at the interface between different components in electrochemical energy devices characterized by multi-layered structures (solid oxide fuel cells and lithium ions batteries).
Boundary and Interface CFTs from the Conformal Bootstrap
F. Gliozzi; P. Liendo; M. Meineri; A. Rago
2015-05-12
We explore some consequences of the crossing symmetry for defect conformal field theories, focusing on codimension one defects like flat boundaries or interfaces. We study surface transitions of the 3d Ising and other O(N) models through numerical solutions to the crossing equations with the method of determinants. In the extraordinary transition, where the low-lying spectrum of the surface operators is known, we use the bootstrap equations to obtain information on the bulk spectrum of the theory. In the ordinary transition the knowledge of the low-lying bulk spectrum allows to calculate the scale dimension of the relevant surface operator, which compares well with known results of two-loop calculations in 3d. Estimates of various OPE coefficients are also obtained. We also analyze in 4-epsilon dimensions the renormalization group interface between the O(N) model and the free theory and check numerically the results in 3d.
Simulations of dislocation pile-ups at assymetric tilt boundaries in aluminum
Valone, Steven [Los Alamos National Laboratory; Wang, Jian M [Los Alamos National Laboratory; Hoagland, Richard C [Los Alamos National Laboratory; Germann, Timothy C [Los Alamos National Laboratory
2011-01-21
Materials deformation processes are increasingly approachable through the both conventional and accelerated molecular dynamics. In one deformation process, dislocation pile-up at a grain boundary, a greater understanding is required as to how dislocations transmit through grain boundaries, causing plastic deformation, or reflect and reconstruct the grain boundary, but with no macroscopic deformation. Here dislocation pile-ups in an alwninum bicrystal with an asymmetric tilt grain boundary are simulated atomistically, introducing effects of dislocation interactions beyond linear elastic ones. The observed responses as functions of the number of explicitly modeled dislocations and the magnitude of the applied stress are discussed. Typical conditions for the simulations consist of thermal relaxation room temperature, five active dislocations inserted within a 6.5-million-atom cell, and an additional fourteen dislocations represented within the atomistic simulation by their elastic strain fields. The dislocations are initially distributed according to linear elastic estimates of their positions in a double-ended pile-up from a chosen far-field stress. The whole cell is allowed to relax according to a procedure to be described. In the ensuing simulations, the system is propagated for some substantial period of time (lOs of ps), followed by small increments of strain. After a number of such increments, we observe all of the anticipated events. Usually several of the closest dislocations are absorbed into the grain boundary, resulting in varying amounts of reconstruction. Reflections from the boundary are common and show a strong dependence on sample thickness. Transmission events are seen on both slip systems in the other grain. The particulars of these events will be described as well.
ECE 390 Electric & Magnetic Fields Catalog Description: Static and quasi-static electric's and Laplace's equations. Boundary value problems, method of images · Steady electric currents, static magnetic, students will be able to... 1. Identify the characteristics of static electric and magnetic fields in free
Poloidal field system design for the ZT-H reversed field pinch experiment
Schoenberg, K.F.; Gribble, R.F.; Linton, T.W.; Reass, W.R.
1983-01-01
This report discusses each of the following areas: (1) equilibrium specification, (2) the equilibrium winding, (3) the magnetizing winding, (4) numerical poloidal field system analysis, (5) coil cross section, turns, minimum field error, (6) coil stresses and cooling, (7) the upper structure, (8) the loads, (9) boundary conditions and method of analysis, and (10) design description. (MOW)
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Uberuaga, Blas Pedro; Vernon, Louis J.; Martinez, Enrique; Voter, Arthur F.
2015-03-13
Nanocrystalline materials have received great attention due to their potential for improved functionality and have been proposed for extreme environments where the interfaces are expected to promote radiation tolerance. However, the precise role of the interfaces in modifying defect behavior is unclear. Using long-time simulations methods, we determine the mobility of defects and defect clusters at grain boundaries in Cu. We find that mobilities vary significantly with boundary structure and cluster size, with larger clusters exhibiting reduced mobility, and that interface sink efficiency depends on the kinetics of defects within the interface via the in-boundary annihilation rate of defects. Thus,more »sink efficiency is a strong function of defect mobility, which depends on boundary structure, a property that evolves with time. Further, defect mobility at boundaries can be slower than in the bulk, which has general implications for the properties of polycrystalline materials. Finally, we correlate defect energetics with the volumes of atomic sites at the boundary.« less
Boundary Plasma Turbulence Simulations for Tokamaks
Xu, X; Umansky, M; Dudson, B; Snyder, P
2008-05-15
The boundary plasma turbulence code BOUT models tokamak boundary-plasma turbulence in a realistic divertor geometry using modified Braginskii equations for plasma vorticity, density (ni), electron and ion temperature (T{sub e}; T{sub i}) and parallel momenta. The BOUT code solves for the plasma fluid equations in a three dimensional (3D) toroidal segment (or a toroidal wedge), including the region somewhat inside the separatrix and extending into the scrape-off layer; the private flux region is also included. In this paper, a description is given of the sophisticated physical models, innovative numerical algorithms, and modern software design used to simulate edge-plasmas in magnetic fusion energy devices. The BOUT code's unique capabilities and functionality are exemplified via simulations of the impact of plasma density on tokamak edge turbulence and blob dynamics.
Open Boundary Conditions for Dissipative MHD
Meier, E T
2011-11-10
In modeling magnetic confinement, astrophysics, and plasma propulsion, representing the entire physical domain is often difficult or impossible, and artificial, or 'open' boundaries are appropriate. A novel open boundary condition (BC) for dissipative MHD, called Lacuna-based open BC (LOBC), is presented. LOBC, based on the idea of lacuna-based truncation originally presented by V.S. Ryaben'kii and S.V. Tsynkov, provide truncation with low numerical noise and minimal reflections. For hyperbolic systems, characteristic-based BC (CBC) exist for separating the solution into outgoing and incoming parts. In the hyperbolic-parabolic dissipative MHD system, such separation is not possible, and CBC are numerically unstable. LOBC are applied in dissipative MHD test problems including a translating FRC, and coaxial-electrode plasma acceleration. Solution quality is compared to solutions using CBC and zero-normal derivative BC. LOBC are a promising new open BC option for dissipative MHD.
Proteoglycan 4 metabolism and boundary lubrication of articular cartilage
Schmidt, Tannin A.
2006-01-01
ability to act as boundary lubricants. Ann Rheum Dis 43:641-load-bearing boundary lubricant in the joint. Br J Rheumatolof the cartilage and lubricant. Arthritis Rheum 11:674-82,
Crystallographically consistent percolation theory for grain boundary networks
Frary, Megan
2005-01-01
Grain boundaries are known to play a role in many important material properties including creep resistance, ductility and cracking resistance. Although the structure and properties of individual boundaries are important, ...
Thermodynamic stability and implications of anisotropic boundary particles
Siem, Ellen J. (Ellen Jane), 1979-
2005-01-01
(cont.) Generally, a boundary is nonplanar in the neighborhood of an attached particle--even when anisotropic interfacial free energies do not produce faceting-and maintains a icKy = 0 while the boundary particles maintain ...
Andersson, Anders D.; Tonks, Michael R.; Casillas, Luis; Nerikar, Pankaj; Vyas, Shyam; Uberuaga, Blas P.; Stanek, Christopher R.
2014-10-31
In light water reactor fuel, gaseous fission products segregate to grain boundaries, resulting in the nucleation and growth of large intergranular fission gas bubbles. Based on the mechanisms established from density functional theory (DFT) and empirical potential calculations 1, continuum models for diffusion of xenon (Xe), uranium (U) vacancies and U interstitials in UO_{2} have been derived for both intrinsic conditions and under irradiation. Segregation of Xe to grain boundaries is described by combining the bulk diffusion model with a model for the interaction between Xe atoms and three different grain boundaries in UO_{2} ( ?5 tilt, ?5 twist and a high angle random boundary),as derived from atomistic calculations. All models are implemented in the MARMOT phase field code, which is used to calculate effective Xe and U diffusivities as well as redistribution for a few simple microstructures.
Mesoscale coupled ocean-atmosphere feedbacks in boundary current systems
Putrasahan, Dian Ariyani
2012-01-01
productive oceanic eastern boundary current, providing anCurrent System and the Kuroshio Extension uses OFES products for their oceanic
Defining window-boundaries for genomic analyses using smoothing...
Office of Scientific and Technical Information (OSTI)
undesirable window boundary specifications, or highly correlated test statistics. We introduce a method for defining windows based on statistically guided...
Correct traction boundary conditions in the indeterminate couple stress model
Patrizio Neff; Ionel-Dumitrel Ghiba; Angela Madeo; Ingo Münch
2015-04-02
In this paper we consider the Grioli-Koiter-Mindlin-Toupin indeterminatecouple stress model. The main aim is to show that the traction boundary conditions were not yet completely deduced. As it turns out, and to our own surprise, restricting the boundary condition framework from the strain gradient models to the couple stress model does not reduce to Mindlin's set of accepted boundary conditions. We present therefore, for the first time the complete, consistent set of traction boundary conditions.
Effects of Boundary Conditions on Single-File Pedestrian Flow
Zhang, Jun; Seyfried, Armin
2015-01-01
In this paper we investigate effects of boundary conditions on one dimensional pedestrian flow which involves purely longitudinal interactions. Qualitatively, stop-and-go waves are observed under closed boundary condition and dissolve when the boundary is open. To get more detailed information the fundamental diagrams of the open and closed systems are compared using Voronoi-based measurement method. Higher maximal specific flow is observed from the pedestrian movement at open boundary condition.
Nonuniqeness in a free boundary problem from combustion
2014-10-31
Nonuniqeness in a free boundary problem from combustion. Arshak Petrosyan joint with Aaron Yip. Department of Mathematics. Purdue University.
Fusion for AdS/CFT boundary S-matrices
Rafael I. Nepomechie; Rodrigo A. Pimenta
2015-09-14
We propose a fusion formula for AdS/CFT worldsheet boundary S-matrices. We show that, starting from the fundamental Y=0 boundary S-matrix, this formula correctly reproduces the two-particle bound-state boundary S-matrices.
An algorithm for determining EF coils from fixed-boundary equilibria applied to ARIES III
Bathke, C. (Los Alamos National Lab., NM (United States)); Jardin, S.C.; Kessel, C.E. (Princeton Univ., NJ (United States). Plasma Physics Lab.)
1991-01-01
An algorithm that determines the external EF coils required to produce equilibria calculated by high-resolution, fixed-boundary codes is described. The algorithm permits the specification of the poloidal-field-null location. The EF-coil positions on a specified surface located just outside of the TF coils are optimized to minimize the stored magnetic energy. Results of the application of this algorithm to ARIES-3 are also presented. 7 refs., 2 figs., 2 tabs.
Harmonic Initial-Boundary Evolution in General Relativity
Maria C. Babiuc; Bela Szilagyi; Jeffrey Winicour
2006-03-14
Computational techniques which establish the stability of an evolution-boundary algorithm for a model wave equation with shift are incorporated into a well-posed version of the initial-boundary value problem for gravitational theory in harmonic coordinates. The resulting algorithm is implemented as a 3-dimensional numerical code which we demonstrate to provide stable, convergent Cauchy evolution in gauge wave and shifted gauge wave testbeds. Code performance is compared for Dirichlet, Neumann and Sommerfeld boundary conditions and for boundary conditions which explicitly incorporate constraint preservation. The results are used to assess strategies for obtaining physically realistic boundary data by means of Cauchy-characteristic matching.
Energy Unit lecture outline & graphics Fritz Stahr Tues 1/21/03 - Transportation of Energy & Energy of Transportation an intricate link - history of settlement & industry largely due to transportation and energy supplies - initial towns on rivers or by sea where ships could service cargo as water
Sediment Geochemistry (OCN/GG 644) Course Outline -- Fall 2015 Date Day Lectu re # Topic Components and Distribution of Marine Sediment Types 1-Sep Tu 3 Physical Properties of Sediments, Sediment Accumulation Rates and Sediment Transport Processes 3-Sep Th 4 Physical Properties of Sediments, Sediment
Walker, Lawrence R.
ADVERTISING POLICY The following policy outlines the usage and advertising procedures Services (SUES) General Reservation Policy. Additional policies may apply per the specifics of the event/advertisement. A. All advertising-related decisions will be managed by the SUES office. Advertising includes
Kovintavewat, Piya
[1] H. P. Hsu, Schaum's outline series: theory and problem of analog and digital communications and Tables. McGraw-Hill, 3rd edition, 2008. [10] M. H. Hayes, Statistical digital signal processing communications: fundamentals and applications. Prentice Hall, 2nd-edition, 2001. [13] J. G. Proakis, Digital
FIELD-BASED TECHNOLOGY EDUCATION: JUST IN TIME TECHNOLOGY TRAINING
Larkin, Teresa L.
FIELD-BASED TECHNOLOGY EDUCATION: JUST IN TIME TECHNOLOGY TRAINING Sarah Irvine Belson1 and Teresa, Audio Technology, and Physics, American University, 4400 Massachusetts Ave. NW, Washington, DC 20016, tlarkin@american.edu Abstract -- This paper outlines the current status of technology integration
Instantons near a tachyonic top in anti de Sitter and the no-boundary regulator
Bum-Hoon Lee; Wonwoo Lee; Daeho Ro; Dong-han Yeom
2014-09-12
We investigate instantons near the tachyonic top in the anti de Sitter (AdS) background. If the mass around the hill-top is above the Breitenlohner-Freedman (BF) bound, then the top is classically stable. When the BF bound is satisfied, it is already known that there can exist instantons with a non-zero probability, though fine-tunings of the potential are required. On the other hand, we may consider the possibility to obtain instantons with a non-zero probability for more natural shape of potentials. We found that the no-boundary regulator is useful to assign a non-zero probability for general instantons near the tachyonic top within a consistent framework. To use the no-boundary regulator, we need to introduce the complexification of fields. One interesting feature is that, for these AdS instantons, the classicality may not be satisfied after the Wick rotation and hence after the nucleation. This magnifies a novel difference between dS and AdS; a semi-classical boundary observer in AdS may notice the dispersion of quantum fields as a kind of uncertainty, while every semi-classical observers in dS are classicalized individually and hence there is no semi-classical observer who can see the quantum dispersion of the scalar field.
Grain boundary characterization in an X750 alloy
Kevin Fisher; Sebastien Teysseyre; Emmanuelle Marquis
2012-11-01
Grain boundary chemistry in an X750 Ni alloy was analyzed by atom probe tomography in an effort to clarify the possible roles of elemental segregation and carbide presence on the stress corrosion cracking behavior of Ni alloys. Two types of cracks are observed: straight cracks along twin boundaries and wavy cracks at general boundaries. It was found that carbides (M23C6 and TiC) are present at both twin and general boundaries, with comparable B and P segregation for all types of grain boundaries. Twin boundaries intercept ?’ precipitates while the general boundaries wave around the ?’ and carbide precipitates. Near a crack tip, oxidation takes place on the periphery of carbide precipitate.
Microfluidics: The no-slip boundary condition
Eric Lauga; Michael P. Brenner; Howard A. Stone
2005-09-28
The no-slip boundary condition at a solid-liquid interface is at the center of our understanding of fluid mechanics. However, this condition is an assumption that cannot be derived from first principles and could, in theory, be violated. We present a review of recent experimental, numerical and theoretical investigations on the subject. The physical picture that emerges is that of a complex behavior at a liquid/solid interface, involving an interplay of many physico-chemical parameters, including wetting, shear rate, pressure, surface charge, surface roughness, impurities and dissolved gas.
Testing the Boundary Conditions of General Relativity Near the Earth-Sun Saddle Point
Tom Martin
1999-06-03
We suggest that a satellite with a stable atomic clock on board be sent through the Earth-Sun gravitational saddle point to experimentally determine whether Nature prefers static solutions of the field equations of General Relativity, such as the standard Schwarzschild solution, or whether Nature prefers equivalent non-static solutions. This is a test of the boundary conditions of General Relativity rather than of the field equations. The fractional difference in clock rates between the two possibilities is a part in a hundred million. This is a large and easily measurable effect.
Fitzpatrick, Richard
elongated tokamak plasmas R. Fitzpatrick Citation: Physics of Plasmas (1994-present) 15, 092502 (2008); doi boundary layer generated by kink modes in tokamaks Phys. Plasmas 18, 062503 (2011); 10.1063/1.3596536 Error-field induced electromagnetic torques in a large aspect-ratio, low- , weakly shaped tokamak plasma Phys
QUASI-POLYNOMIAL MIXING OF THE 2D STOCHASTIC ISING MODEL WITH "PLUS" BOUNDARY UP TO CRITICALITY
Lubetzky, Eyal
magnetic field. While the classical study of the Ising model concentrated on its static properties, over including heat-bath and Metropolis. It is known that on a box of side-length L in Z2 with free boundary unstable and as such the reduced bottleneck be- tween the two phases drastically accelerates the rate
Tracking tumor boundary in MV-EPID images without implanted markers: A feasibility study
Zhang, Xiaoyong Homma, Noriyasu; Ichiji, Kei; Takai, Yoshihiro; Yoshizawa, Makoto
2015-05-15
Purpose: To develop a markerless tracking algorithm to track the tumor boundary in megavoltage (MV)-electronic portal imaging device (EPID) images for image-guided radiation therapy. Methods: A level set method (LSM)-based algorithm is developed to track tumor boundary in EPID image sequences. Given an EPID image sequence, an initial curve is manually specified in the first frame. Driven by a region-scalable energy fitting function, the initial curve automatically evolves toward the tumor boundary and stops on the desired boundary while the energy function reaches its minimum. For the subsequent frames, the tracking algorithm updates the initial curve by using the tracking result in the previous frame and reuses the LSM to detect the tumor boundary in the subsequent frame so that the tracking processing can be continued without user intervention. The tracking algorithm is tested on three image datasets, including a 4-D phantom EPID image sequence, four digitally deformable phantom image sequences with different noise levels, and four clinical EPID image sequences acquired in lung cancer treatment. The tracking accuracy is evaluated based on two metrics: centroid localization error (CLE) and volume overlap index (VOI) between the tracking result and the ground truth. Results: For the 4-D phantom image sequence, the CLE is 0.23 ± 0.20 mm, and VOI is 95.6% ± 0.2%. For the digital phantom image sequences, the total CLE and VOI are 0.11 ± 0.08 mm and 96.7% ± 0.7%, respectively. In addition, for the clinical EPID image sequences, the proposed algorithm achieves 0.32 ± 0.77 mm in the CLE and 72.1% ± 5.5% in the VOI. These results demonstrate the effectiveness of the authors’ proposed method both in tumor localization and boundary tracking in EPID images. In addition, compared with two existing tracking algorithms, the proposed method achieves a higher accuracy in tumor localization. Conclusions: In this paper, the authors presented a feasibility study of tracking tumor boundary in EPID images by using a LSM-based algorithm. Experimental results conducted on phantom and clinical EPID images demonstrated the effectiveness of the tracking algorithm for visible tumor target. Compared with previous tracking methods, the authors’ algorithm has the potential to improve the tracking accuracy in radiation therapy. In addition, real-time tumor boundary information within the irradiation field will be potentially useful for further applications, such as adaptive beam delivery, dose evaluation.
A Simple Parameterization Coupling the Convective Daytime Boundary Layer and Fair-Weather Cumuli
Berg, Larry K.; Stull, Roland B.
2005-06-15
A new parameterization for boundary-layer cumulus clouds, called the Cumulus Potential (CuP) scheme is introduced. This scheme uses Joint Probability Density Functions (JPDFs) of virtual potential temperature and water-vapor mixing ratio, as well as the mean vertical profiles of virtual potential temperature to predict the amount and size distribution of boundary-layer cloud cover. This model considers the diversity of air parcels over a heterogeneous surface, and recognizes that some parcels rise above their lifting condensation level to become cumulus, while other parcels might rise as non-cloud updrafts. This model has several unique features: (1) cloud cover is determined from the boundary-layer JPDF of virtual potential temperature vs. water-vapor mixing ratio , (2) clear and cloudy thermals are allowed to coexist at the same altitude, and (3) a range of cloud-base heights, cloud-top heights, and cloud thicknesses are predicted within any one cloud field, as observed. Using data from Boundary Layer Experiment 1996, and a model intercomparsion study using Large Eddy Simulation (LES) based on BOMEX, it is shown that the CuP model does a good job predicting cloud-base height and cloud-top height. The model also shows promise in predicting cloud cover, and is found to give better cloud-cover estimates than three other cumulus parameterizations: one based on relative humidity, a statistical scheme based on the saturation deficit, and a slab model.
Zhijie Xu
2012-07-01
We introduce a new method of solution for the convective heat transfer under forced laminar flow that is confined by two parallel plates with a distance of 2a or by a circular tube with a radius of a. The advection-conduction equation is first mapped onto the boundary. The original problem of solving the unknown field T(x,r,t) is reduced to seek the solutions of T at the boundary (r = a or r = 0, r is the distance from the centerline shown in Fig. 1), i.e., the boundary functions T{sub a}(x,t) {triple_bond} T(x,r=a,t) and/or T{sub 0}(x,t) {triple_bond} T(x,r=0,t). In this manner, the original problem is significantly simplified by reducing the problem dimensionality from 3 to 2. The unknown field T(x,r,t) can be eventually solved in terms of these boundary functions. The method is applied to the convective heat transfer with uniform wall temperature boundary condition and with heat exchange between flowing fluids and its surroundings that is relevant to the geothermal applications. Analytical solutions are presented and validated for the steady-state problem using the proposed method.
Xu, Zhijie
2012-07-01
We introduce a method of solution for the convective heat transfer under forced laminar flow that is confined by two parallel plates with a distance of 2a or by a circular tube with a radius of a. The advection-conduction equation is first mapped onto the boundary. The original problem of solving the unknown field is reduced to seek the solutions of T at the boundary (r=a or r=0, r is the distance from the centerline shown in Fig. 1), i.e. the boundary functions and/or . In this manner, the original problem is significantly simplified by reducing the problem dimensionality from 3 to 2. The unknown field can be eventually solved in terms of these boundary functions. The method is applied to the convective heat transfer with uniform wall temperature boundary condition and with heat exchange between flowing fluids and its surroundings that is relevant to the geothermal applications. Analytical solutions are presented and validated for the steady state problem using the proposed method.
Quantum reduced loop gravity: extension to scalar field
Jakub Bilski; Emanuele Alesci; Francesco Cianfrani
2015-07-02
The quantization of the Hamiltonian for a scalar field is performed in the framework of Quantum Reduced Loop Gravity. We outline how the regularization can be performed by using the analogous tools adopted in full Loop Quantum Gravity and the matrix elements of the resulting operator between basis states are analytic coefficients. These achievements open the way for a consistent analysis of the Quantum Gravity corrections to the classical dynamics of gravity in the presence of a scalar field in a cosmological setting.
Moestl, U. V.; Temmer, M.; Veronig, A. M.
2013-03-20
The Atmospheric Imaging Assembly on board the Solar Dynamics Observatory observed a coronal mass ejection with an embedded filament on 2011 February 24, revealing quasi-periodic vortex-like structures at the northern side of the filament boundary with a wavelength of approximately 14.4 Mm and a propagation speed of about 310 {+-} 20 km s{sup -1}. These structures could result from the Kelvin-Helmholtz instability occurring on the boundary. We perform 2.5D numerical simulations of the Kelvin-Helmholtz instability and compare the simulated characteristic properties of the instability with the observations, where we obtain qualitative as well as quantitative accordance. We study the absence of Kelvin-Helmholtz vortex-like structures on the southern side of the filament boundary and find that a magnetic field component parallel to the boundary with a strength of about 20% of the total magnetic field has stabilizing effects resulting in an asymmetric development of the instability.
Dunin-Borkowski, Rafal E.
that is required when interpreting signals recorded from ferroelectric materials using both DPC imaging and other. A clear differential signal is seen, which matches the expected direction of the electric field in crystallographic structure at the boundary and not from an electric field. This study highlights the care
Peterson, J.; Hanson, J.; Hartwell, G.; Knowlton, S. [Department of Physics, Auburn University, Auburn, Alabama 36849 (United States)
2010-03-15
Understanding the behavior of plasmas in magnetic confinement fusion devices typically requires accurate knowledge of the magnetic field structure. In stellarator-type confinement devices, the helical magnetic field is produced by currents in external coils and may be traced experimentally in the absence of plasma through the experimental technique of vacuum magnetic field mapping. Field mapping experiments, such as these, were performed on the recently constructed compact toroidal hybrid to verify the range of accessible magnetic configurations, compare the actual magnetic configuration with the design configuration, and identify any vacuum field errors that lead to perturbations of the vacuum magnetic flux surfaces. Furthermore, through the use of a new coil optimization routine, modifications are made to the simulation coil model such that better agreement exists between the experimental and simulation results. An outline of the optimization procedure is discussed in conjunction with the results of one such optimization process performed on the helical field coil.
First order gravity: Actions, topological terms and boundaries
Corichi, Alejandro; Vukasinac, Tatjana
2013-01-01
We consider first order gravity in four dimensions. This means that the fundamental variables are a tetrad $e$ and a SO(3,1) connection $\\omega$. We study the most general action principle compatible with diffeomorphism invariance. This implies, in particular, considering besides the standard Einstein-Hilbert term, other terms that either do not change the equations of motion, or are topological in nature. Having a well defined action principle also implies adding additional boundary terms, whose detailed form may depend on the particular boundary conditions at hand. We consider spacetimes that include a boundary at infinity, satisfying asymptotically flat boundary conditions and/or an internal boundary satisfying isolated horizons boundary conditions. For our analysis we employ the covariant Hamiltonian formalism where the phase space $\\Gamma$ is given by solutions to the equation of motion. For each of the possible terms contributing to the action we study the well posedness of the action, its finiteness, t...
Aster, R.; Flores, R. [New Mexico Inst. of Mining and Technology, Socorro, NM (United States); Fehler, M. [Los Alamos National Lab., NM (United States)
1995-06-01
The widely-used algorithm of Crouch and Starfield is unstable when used to solve our mixed boundary equation problem of interest. Altering the boundary conditions and correspondingly rearranging the system of equations to utilize double-sided boundary elements overcomes this drawback. The new algorithm described here is more physically realistic as in that it allows for rotation of the fault segments in the strain field resulting from satisfying the fault static shear strength condition. Preliminary test results indicate that a fault trifurcation gap model may describe the non-strike slip components to some of the seismicity.
Effective Hydrodynamic Boundary Conditions for Corrugated Surfaces
Mongruel, Anne; Asmolov, Evgeny S; Vinogradova, Olga I
2012-01-01
We report measurements of the hydrodynamic drag force acting on a smooth sphere falling down under gravity to a plane decorated with microscopic periodic grooves. Both surfaces are lyophilic, so that a liquid (silicone oil) invades the surface texture being in the Wenzel state. A significant decrease in the hydrodynamic resistance force as compared with that predicted for two smooth surfaces is observed. To quantify the effect of roughness we use the effective no-slip boundary condition, which is applied at the imaginary smooth homogeneous isotropic surface located at an intermediate position between top and bottom of grooves. Such an effective condition fully characterizes the force reduction measured with the real surface, and the location of this effective plane is related to geometric parameters of the texture by a simple analytical formula.
Numerical magnetohydrodynamic simulations of expanding flux ropes: Influence of boundary driving
Tacke, Thomas; Dreher, Jürgen [Theoretische Physik I, Ruhr-Universität Bochum, Bochum (Germany)] [Theoretische Physik I, Ruhr-Universität Bochum, Bochum (Germany); Sydora, Richard D. [Department of Physics, University of Alberta, Edmonton, Alberta T6G 2E1 (Canada)] [Department of Physics, University of Alberta, Edmonton, Alberta T6G 2E1 (Canada)
2013-07-15
The expansion dynamics of a magnetized, current-carrying plasma arch is studied by means of time-dependent ideal MHD simulations. Initial conditions model the setup used in recent laboratory experiments that in turn simulate coronal loops [J. Tenfelde et al., Phys. Plasmas 19, 072513 (2012); E. V. Stenson and P. M. Bellan, Plasma Phys. Controlled Fusion 54, 124017 (2012)]. Boundary conditions of the electric field at the “lower” boundary, intersected by the arch, are chosen such that poloidal magnetic flux is injected into the domain, either localized at the arch footpoints themselves or halfway between them. These conditions are motivated by the tangential electric field expected to exist in the laboratory experiments due to the external circuit that drives the plasma current. The boundary driving is found to systematically enhance the expansion velocity of the plasma arch. While perturbations at the arch footpoints also deform its legs and create characteristic elongated segments, a perturbation between the footpoints tends to push the entire structure upwards, retaining an ellipsoidal shape.
Evaluation of wall boundary condition parameters for gas-solids...
Office of Scientific and Technical Information (OSTI)
predictions of various gas-solids fluidized beds. Several models for the granular flow wall boundary condition are available in the open literature for numerical modeling of...
A major lithospheric boundary in eastern California defined by...
ratios of Miocene-Recent basalts in eastern California, when screened for crustal contamination, vary dramatically and indicate the presence of a major lithospheric boundary that...
[Perovskite and Fluorite Grain Boundary Properties]. Final Project Report
Browning, N. D.
2004-02-24
One of the main areas of research in the last two years in this program has been the properties of grain boundaries in perovskite and fluorite structure materials.
Short wavelength topography on the inner-core boundary
Cao, A.; Masson, Y.; Romanowicz, B.
2006-01-01
Short wavelength topography on the inner-core boundary Aimin94720 Constraining the topography of the inner-core boundaryindicates the presence of topography at the inner- core
OPTIMAL REGULARITY AND THE FREE BOUNDARY IN THE ...
2013-06-25
nomenon of osmosis and osmotic pressure in biochemistry), and the problems on the temperature control on the boundary in thermics. We refer to the book of.
Mineral Deformation at Earth's Core-Mantle Boundary
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
At the core-mantle boundary (CMB), 2900 km deep, seismologists have discovered that seismic waves travel faster in certain directions. This seismic anisotropy appears to be...
Friction of Steel Sliding Under Boundary Lubrication Regime in...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
how to increase engine efficiency by reducing parasitic boundary regime friction losses and enable operation with lower viscosity oils while maintaining engine durability....
Sandia Energy - Elucidating the Role of Twin Boundaries in Deformation...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Impact Coupled experiment and modeling reveal the dramatic and complex impact of high-density twin boundaries on microstructure evolution and deformation mechanisms Research...
Jeon, Y M
2015-01-01
A free-boundary Tokamak Equilibrium Solver (TES), developed for advanced study of tokamak equilibra, is described with two distinctive features. One is a generalized method to resolve the intrinsic axisymmetric instability, which is encountered after all in equilibrium calculation with a free-boundary condition. The other is an extension to deal with a new divertor geometry such as snowflake or X divertors. For validations, the uniqueness of a solution is confirmed by the independence on variations of computational domain, the mathematical correctness and accuracy of equilibrium profiles are checked by a direct comparison with an analytic equilibrium known as a generalized Solovev equilibrium, and the governing force balance relation is tested by examining the intrinsic axisymmetric instabilities. As a valuable application, a snowflake equilibrium that requires a second order zero of the poloidal magnetic field is discussed in the circumstance of KSTAR coil system.
THE MONOCLINIC PHASE IN PZT: NEW LIGHT ON MORPHOTROPIC PHASE BOUNDARIES
NOHEDA,B.; GONZALO,J.A.; GUO,R.; PARK,S.E.; CROSS,L.E.; COX,D.E.; SHIRANE,G.
2000-03-09
A summary of the work recently carried out on the morphotropic phase boundary (MPB) of PZT is presented. By means of x-ray powder diffraction on ceramic samples of excellent quality, the MPB has been successfully characterized by changing temperature in a series of closely spaced compositions. As a result, an unexpected monoclinic phase has been found to exist in between the well-known tetragonal and rhombohedral PZT phases. A detailed structural analysis, together with the investigation of the field effect in this region of compositions, have led to an important advance in understanding the mechanisms responsible for the physical properties of PZT as well as other piezoelectric materials with similar morphotropic phase boundaries.
Vladimir Maz'ya; Alexander Movchan; Michael Nieves
2010-05-24
We describe a method of asymptotic approximations to solutions of mixed boundary value problems for the Laplacian in a three-dimensional domain with many perforations of arbitrary shape, with the Neumann boundary conditions being prescribed on the surfaces of small voids. The only assumption made on the geometry is that the diameter of a void is assumed to be smaller compared to the distance to the nearest neighbour. The asymptotic approximation, obtained here, involves a linear combination of dipole fields constructed for individual voids, with the coefficients, which are determined by solving a linear algebraic system. We prove the solvability of this system and derive an estimate for its solution. The energy estimate is obtained for the remainder term of the asymptotic approximation.
Maz'ya, Vladimir; Nieves, Michael
2010-01-01
We describe a method of asymptotic approximations to solutions of mixed boundary value problems for the Laplacian in a three-dimensional domain with many perforations of arbitrary shape, with the Neumann boundary conditions being prescribed on the surfaces of small voids. The only assumption made on the geometry is that the diameter of a void is assumed to be smaller compared to the distance to the nearest neighbour. The asymptotic approximation, obtained here, involves a linear combination of dipole fields constructed for individual voids, with the coefficients, which are determined by solving a linear algebraic system. We prove the solvability of this system and derive an estimate for its solution. The energy estimate is obtained for the remainder term of the asymptotic approximation.
Oil and Gas Field Code Master List 1990
Not Available
1991-01-04
This is the ninth annual edition of the Energy Information Administration's (EIA) Oil and Gas Field Code Master List. It reflects data collected through October 1990 and provides standardized field name spellings and codes for all identified oil and/or gas fields in the United States. There are 54,963 field records in this year's Oil and Gas Field Code Master List (FCML). This amounts to 467 more than in last year's report. As it is maintained by EIA, the Master List includes: Field records for each state and county in which a field resides; field records for each offshore area block in the Gulf of Mexico in which a field resides;field records for each alias field name; fields crossing state boundaries that may be assigned different names by the respective state naming authorities.
Computing nonlinear force free coronal magnetic fields
T. Wiegelmann; T. Neukirch
2008-01-21
Knowledge of the structure of the coronal magnetic field is important for our understanding of many solar activity phenomena, e.g. flares and CMEs. However, the direct measurement of coronal magnetic fields is not possible with present methods, and therefore the coronal field has to be extrapolated from photospheric measurements. Due to the low plasma beta the coronal magnetic field can usually be assumed to be approximately force free, with electric currents flowing along the magnetic field lines. There are both observational and theoretical reasons which suggest that at least prior to an eruption the coronal magnetic field is in a nonlinear force free state. Unfortunately the computation of nonlinear force free fields is way more difficult than potential or linear force free fields and analytic solutions are not generally available. We discuss several methods which have been proposed to compute nonlinear force free fields and focus particularly on an optimization method which has been suggested recently. We compare the numerical performance of a newly developed numerical code based on the optimization method with the performance of another code based on an MHD relaxation method if both codes are applied to the reconstruction of a semi-analytic nonlinear force-free solution. The optimization method has also been tested for cases where we add random noise to the perfect boundary conditions of the analytic solution, in this way mimicking the more realistic case where the boundary conditions are given by vector magnetogram data. We find that the convergence properties of the optimization method are affected by adding noise to the boundary data and we discuss possibilities to overcome this difficulty.
L. P. Teo
2013-04-29
We consider the finite temperature Casimir stress acting on the boundary of a D>=3 dimensional cavity due to the vacuum fluctuations of electromagnetic fields. Both perfectly conducting and infinitely permeable boundary conditions are considered, and it is proved that they correspond mathematically to the relative and absolute boundary conditions. The divergence terms of the Casimir free energy are related to the heat kernel coefficients of the Laplace operator. It is shown that the Casimir stress is free of divergence if and only if D is exactly three. The high temperature asymptotics of the regularized Casimir free energy are also found to depend on the heat kernel coefficients. When D>3, renormalization is required to remove terms of order higher than or equal to T^2.
T-duality trivializes bulk-boundary correspondence
Varghese Mathai; Guo Chuan Thiang
2015-07-26
Recently we introduced T-duality in the study of topological insulators. In this paper, we study the bulk-boundary correspondence for three phenomena in condensed matter physics, namely, the quantum Hall effect, the Chern insulator, and time reversal invariant topological insulators. In all of these cases, we show that T-duality trivializes the bulk-boundary correspondence.
Boundary lubrication under water Wuge H. Briscoe1
Klein, Jacob
LETTERS Boundary lubrication under water Wuge H. Briscoe1 , Simon Titmuss1 , Fredrik Tiberg1 {, Robert K. Thomas1 , Duncan J. McGillivray1 { & Jacob Klein1,2 Boundary lubrication, in which the rubbing. This process, wide- spread in engineering applications, is also predicted to occur in biological lubrication
Modal Analysis of Homogeneous Optical Waveguides by Boundary Integral Method
Modal Analysis of Homogeneous Optical Waveguides by Boundary Integral Method Lei Wang J. Allen Cox of the waveguide. Two dierent systems of boundary integral equations are derived for the numerical solutions of the discrete propagation constants; one of them is in the form of Fredholm integral equations of the second
ANNIVERSARY REVIEW Grain boundary energy anisotropy: a review
Rohrer, Gregory S.
energy (B) gained when the two surfaces are brought together and new bonds are formed. The grain boundary with the stiffness of the material. The excess energy of the grANNIVERSARY REVIEW Grain boundary energy anisotropy: a review Gregory S. Rohrer Received: 29 April
Stability of High-Speed, Three-Dimensional Boundary Layers
Craig, Stuart A
2015-04-02
Boundary-layer experiments are performed in the low-disturbance, Mach 6 Quiet Tunnel (M6QT) at Texas A&M University. The experiments are focused specifically on investigating the physics of two three-dimensional phenomena in hypersonic boundary...
LARGE EDDY SIMULATION OF TURBULENT BOUNDARY LAYERS OVER ROUGH BEDS
Pawlak, Geno
that determines the response of the boundary layer is not clear. One method to characterize the irregular nature with different spectral slopes using 2D 10 % loading square waves as basis functions. These square waves can) is then used to simulate the turbulent boundary layer over the rough beds. The LES solver is first validated
Aero-Optical Effects of Supersonic Boundary Layers Stanislav Gordeyev
Gordeyev, Stanislav
Aero-Optical Effects of Supersonic Boundary Layers Stanislav Gordeyev and Eric Jumper University, Colorado 80840 DOI: 10.2514/1.J051266 Aero-optical measurements of a zero-pressure-gradient, supersonic to describe aero-optical effects of both the subsonic and the supersonic boundary layers. Finally, this new
Detecting Subject Boundaries Within Text: A Language Independent Statistical Approach
Edinburgh, University of
Detecting Subject Boundaries Within Text: A Language Independent Statistical Approach Korin describe here an algorithm for detect ing subject boundaries within text based on a statistical lexical assumptions is that a change in subject is accompanied by a change in vo cabulary. Using this assumption
ENERGETIC PARTICLE ANISOTROPIES AT THE HELIOSPHERIC BOUNDARY
Florinski, V.; Le Roux, J. A. [Department of Space Sciences, University of Alabama in Huntsville, Huntsville, AL 35899 (United States)] [Department of Space Sciences, University of Alabama in Huntsville, Huntsville, AL 35899 (United States); Jokipii, J. R. [Department of Planetary Sciences and Lunar and Planetary Lab, University of Arizona, Tucson, AZ 85721 (United States)] [Department of Planetary Sciences and Lunar and Planetary Lab, University of Arizona, Tucson, AZ 85721 (United States); Alouani-Bibi, F. [Center for Space Plasma and Aeronomic Research, University of Alabama in Huntsville, Huntsville, AL 35899 (United States)] [Center for Space Plasma and Aeronomic Research, University of Alabama in Huntsville, Huntsville, AL 35899 (United States)
2013-10-20
In 2012 August the Voyager 1 space probe entered a distinctly new region of space characterized by a virtual absence of heliospheric energetic ions and magnetic fluctuations, now interpreted as a part of the local interstellar cloud. Prior to their disappearance, the ion distributions strongly peaked at a 90° pitch angle, implying rapid escape of streaming particles along the magnetic field lines. Here we investigate the process of particle crossing from the heliosheath into the interstellar space, using a kinetic approach that resolves scales of the particle's cyclotron radius and smaller. It is demonstrated that a 'pancake' pitch-angle distribution naturally arises at a tangential discontinuity separating a weakly turbulent plasma from a laminar region with a very low pitch-angle scattering rate. The relatively long persistence of gyrating ions is interpreted in terms of field line meandering facilitating their cross-field diffusion within the depletion region.
Multi-field inflation from holography
Garriga, Jaume; Urakawa, Yuko [Departament de Física Fonamental i Institut de Ciències del Cosmos, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona (Spain); Skenderis, Kostas, E-mail: jaume.garriga@ub.edu, E-mail: K.Skenderis@soton.ac.uk, E-mail: urakawa.yuko@h.mbox.nagoya-u.ac.jp [STAG Research Centre and Mathematical Sciences, University of Southampton, Southampton SO17 1BJ (United Kingdom)
2015-01-01
We initiate the study of multi-field inflation using holography. Bulk light scalar fields correspond to nearly marginal operators in the boundary theory and the dual quantum field theory is a deformation of a CFT by such operators. We compute the power spectra of adiabatic and entropy perturbations in a simple model and find that the adiabatic curvature perturbation is not conserved in the presence of entropy perturbations but becomes conserved when the entropy perturbations are set to zero or the model is effectively a single scalar model, in agreement with expectations from cosmological perturbation theory.
SUPERSONIC SHEAR INSTABILITIES IN ASTROPHYSICAL BOUNDARY LAYERS
Belyaev, Mikhail A.; Rafikov, Roman R., E-mail: rrr@astro.princeton.edu [Department of Astrophysical Sciences, Princeton University, Ivy Lane, Princeton, NJ 08540 (United States)
2012-06-20
Disk accretion onto weakly magnetized astrophysical objects often proceeds via a boundary layer (BL) that forms near the object's surface, in which the rotation speed of the accreted gas changes rapidly. Here, we study the initial stages of formation for such a BL around a white dwarf or a young star by examining the hydrodynamical shear instabilities that may initiate mixing and momentum transport between the two fluids of different densities moving supersonically with respect to each other. We find that an initially laminar BL is unstable to two different kinds of instabilities. One is an instability of a supersonic vortex sheet (implying a discontinuous initial profile of the angular speed of the gas) in the presence of gravity, which we find to have a growth rate of order (but less than) the orbital frequency. The other is a sonic instability of a finite width, supersonic shear layer, which is similar to the Papaloizou-Pringle instability. It has a growth rate proportional to the shear inside the transition layer, which is of order the orbital frequency times the ratio of stellar radius to the BL thickness. For a BL that is thin compared to the radius of the star, the shear rate is much larger than the orbital frequency. Thus, we conclude that sonic instabilities play a dominant role in the initial stages of nonmagnetic BL formation and give rise to very fast mixing between disk gas and stellar fluid in the supersonic regime.
Irradiation Assisted Grain Boundary Segregation in Steels
Lu, Zheng; Faulkner, Roy G.
2008-07-01
The understanding of radiation-induced grain boundary segregation (RIS) has considerably improved over the past decade. New models have been introduced and much effort has been devoted to obtaining comprehensive information on segregation from the literature. Analytical techniques have also improved so that chemical analysis of layers 1 nm thick is almost routine. This invited paper will review the major methods used currently for RIS prediction: namely, Rate Theory, Inverse Kirkendall, and Solute Drag approaches. A summary is made of the available data on phosphorus RIS in reactor pressure vessel (RPV) steels. This will be discussed in the light of the predictions of the various models in an effort to show which models are the most reliable and easy to use for forecasting P segregation behaviour in steels. A consequence of RIS in RPV steels is a radiation induced shift in the ductile to brittle transition temperature (DBTT). It will be shown how it is possible to relate radiation-induced P segregation levels to DBTT shift. Examples of this exercise will be given for RPV steels and for ferritic steels being considered for first wall fusion applications. Cr RIS in high alloy stainless steels and associated irradiation-assisted stress corrosion cracking (IASCC) will be briefly discussed. (authors)
T. Thiemann
1993-10-29
There is a gap that has been left open since the formulation of general relativity in terms of Ashtekar's new variables namely the treatment of asymptotically flat field configurations that are general enough to be able to define the generators of the Lorentz subgroup of the asymptotical Poincar\\'e group. While such a formulation already exists for the old geometrodynamical variables, up to now only the generators of the translation subgroup could be defined because the function spaces of the fields considered earlier are taken too special. The transcription of the framework from the ADM variables to Ashtekar's variables turns out not to be straightforward due to the freedom to choose the internal SO(3) frame at spatial infinity and due to the fact that the non-trivial reality conditions of the Ashtekar framework reenter the game when imposing suitable boundary conditions on the fields and the Lagrange multipliers.
T. Thiemann
1999-10-04
There is a gap that has been left open since the formulation of general relativity in terms of Ashtekar's new variables namely the treatment of asymptotically flat field configurations that are general enough to be able to define the generators of the Lorentz subgroup of the asymptotical Poincar\\'e group. While such a formulation already exists for the old geometrodynamical variables, up to now only the generators of the translation subgroup could be defined because the function spaces of the fields considered earlier are taken too special. The transcription of the framework from the ADM variables to Ashtekar's variables turns out not to be straightforward due to the a priori freedom to choose the internal SO(3) frame at spatial infinity and due to the fact that the non-trivial reality conditions of the Ashtekar framework reenter the stage when imposing suitable boundary conditions on the fields and the Lagrange multipliers.
Bazalii, B V; Degtyarev, S P
2013-07-31
An elliptic boundary-value problem for second-order equations with nonnegative characteristic form is investigated in the situation when there is a weak degeneracy on the boundary of the domain. A priori estimates are obtained for solutions and the problem is proved to be solvable in some weighted Hölder spaces. Bibliography: 18 titles.
Rohrer, Gregory S.
The Relationship Between Grain Boundary Energy, Grain Boundary Complexion Transitions, and Grain complexions. One idea is that complexion transitions occur to lower the average energy of the interface energy. Experiments on doped aluminas have shown that a complexion transition can change the relative
A fast multigrid-based electromagnetic eigensolver for curved metal boundaries on the Yee mesh
Bauer, Carl A., E-mail: carl.bauer@colorado.edu [Department of Physics and the Center for Integrated Plasma Studies, University of Colorado, Boulder, CO 80309 (United States); Werner, Gregory R. [Department of Physics and the Center for Integrated Plasma Studies, University of Colorado, Boulder, CO 80309 (United States)] [Department of Physics and the Center for Integrated Plasma Studies, University of Colorado, Boulder, CO 80309 (United States); Cary, John R. [Department of Physics and the Center for Integrated Plasma Studies, University of Colorado, Boulder, CO 80309 (United States) [Department of Physics and the Center for Integrated Plasma Studies, University of Colorado, Boulder, CO 80309 (United States); Tech-X Corporation, Boulder, CO 80303 (United States)
2013-10-15
For embedded boundary electromagnetics using the Dey–Mittra (Dey and Mittra, 1997) [1] algorithm, a special grad–div matrix constructed in this work allows use of multigrid methods for efficient inversion of Maxwell’s curl–curl matrix. Efficient curl–curl inversions are demonstrated within a shift-and-invert Krylov-subspace eigensolver (open-sourced at ([ofortt]https://github.com/bauerca/maxwell[cfortt])) on the spherical cavity and the 9-cell TESLA superconducting accelerator cavity. The accuracy of the Dey–Mittra algorithm is also examined: frequencies converge with second-order error, and surface fields are found to converge with nearly second-order error. In agreement with previous work (Nieter et al., 2009) [2], neglecting some boundary-cut cell faces (as is required in the time domain for numerical stability) reduces frequency convergence to first-order and surface-field convergence to zeroth-order (i.e. surface fields do not converge). Additionally and importantly, neglecting faces can reduce accuracy by an order of magnitude at low resolutions.
Tachyonic field interacting with Scalar (Phantom) Field
Surajit Chattopadhyay; Ujjal Debnath
2009-01-29
In this letter, we have considered the universe is filled with the mixture of tachyonic field and scalar or phantom field. If the tachyonic field interacts with scalar or phantom field, the interaction term decays with time and the energy for scalar field is transferred to tachyonic field or the energy for phantom field is transferred to tachyonic field. The tachyonic field and scalar field potentials always decrease, but phantom field potential always increases.
Effective zero-thickness model for a conductive membrane driven by an electric field
Bazant, Martin Z.
The behavior of a conductive membrane in a static (dc) electric field is investigated theoretically. An effective zero-thickness model is constructed based on a Robin-type boundary condition for the electric potential at ...
New York, June 5, 2014 Rick Field Florida/CDF/CMS Page 1
Field, Richard
LHCP 2014 New York, June 5, 2014 Rick Field Florida/CDF/CMS Page 1 Outline of Talk CDF Run 2 300 LHCP2013 8.7 fb-1 Phys. Rev. D 88, 072008 (2013) #12;LHCP 2014 New York, June 5, 2014 Rick Field) Many Data/Theory Comparisons! #12;LHCP 2014 New York, June 5, 2014 Rick Field Florida/CDF/CMS Page 4
Feenstra, Roeland [ORNL; Sinclair IV, John W [ORNL; Thompson, James R [ORNL; Christen, David K [ORNL
2011-01-01
A generalized methodology is described for determining both the intragranular and through-grain-boundary critical current densities in practical coated conductors from contact-free magnetic hysteresis measurements. The model incorporates the vector nature of current density J within the superconducting grains and current conservation with respect to the grain boundaries. Using physically observed values for the grain aspect ratio as input, the analysis yields the low-field intragranular critical current density J{sub c}{sup G} from a single field-dependent measurement of the global J{sub c} and provides a consistent description that spans the entire range from the weak-link (J{sub c}/J{sub c}{sup G}) to the single-grain (J{sub c}/J{sub c}{sup G} {yields} 1) limit. Results are given for ex situ processed RBCO coatings on RABiTS.
Size distribution and structure of Barchan dune fields
Orencio Durán; Veit Schwämmle; Pedro G. Lind; Hans J. Herrmann
2011-05-19
Barchans are isolated mobile dunes often organized in large dune fields. Dune fields seem to present a characteristic dune size and spacing, which suggests a cooperative behavior based on dune interaction. In Duran et al. (2009), we propose that the redistribution of sand by collisions between dunes is a key element for the stability and size selection of barchan dune fields. This approach was based on a mean-field model ignoring the spatial distribution of dune fields. Here, we present a simplified dune field model that includes the spatial evolution of individual dunes as well as their interaction through sand exchange and binary collisions. As a result, the dune field evolves towards a steady state that depends on the boundary conditions. Comparing our results with measurements of Moroccan dune fields, we find that the simulated fields have the same dune size distribution as in real fields but fail to reproduce their homogeneity along the wind direction.
Science at the interface : grain boundaries in nanocrystalline metals.
Rodriguez, Mark Andrew; Follstaedt, David Martin; Knapp, James Arthur; Brewer, Luke N.; Holm, Elizabeth Ann; Foiles, Stephen Martin; Hattar, Khalid M.; Clark, Blythe B.; Olmsted, David L.; Medlin, Douglas L.
2009-09-01
Interfaces are a critical determinant of the full range of materials properties, especially at the nanoscale. Computational and experimental methods developed a comprehensive understanding of nanograin evolution based on a fundamental understanding of internal interfaces in nanocrystalline nickel. It has recently been shown that nanocrystals with a bi-modal grain-size distribution possess a unique combination of high-strength, ductility and wear-resistance. We performed a combined experimental and theoretical investigation of the structure and motion of internal interfaces in nanograined metal and the resulting grain evolution. The properties of grain boundaries are computed for an unprecedented range of boundaries. The presence of roughening transitions in grain boundaries is explored and related to dramatic changes in boundary mobility. Experimental observations show that abnormal grain growth in nanograined materials is unlike conventional scale material in both the level of defects and the formation of unfavored phases. Molecular dynamics simulations address the origins of some of these phenomena.
Grain Boundary (GB) Studies in Nano- and Micro- Crystalline Materials
Tanju, Mst Sohanazaman
2011-01-01
boundaries in silicon? Materials research society, Vol.122,bicrystal? Journal of Materials Science, 40(2005)3137- 5.in ZnO? Journal of Materials Science, 40(2005)3067-3074. 6.
Examining A Hypersonic Turbulent Boundary Layer at Low Reynolds Number
Semper, Michael Thomas
2013-05-15
The purpose of the current study was to answer several questions related to hypersonic, low Reynolds number, turbulent boundary layers, of which available data related to turbulence quantities is scarce. To that end, a ...
Performance of a boundary layer ingesting propulsion system
Plas, Angélique (Angélique Pascale)
2006-01-01
This thesis presents an assessment of the aerodynamic performance of an aircraft propulsion system, with embedded engines, in the presence of aircraft fuselage boundary layer ingestion (BLI). The emphasis is on defining ...
Reconfiguring Boundary Relations: Robotic Innovations in Pharmacy Work
Barrett, Michael
Robotics is a rapidly expanding area of digital innovation with important implications for organizational practice in multioccupational settings. This paper explores the influence of robotic innovations on the boundary ...
Mineral Deformation at Earth's Core-Mantle Boundary
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
for its liquid-iron outer core), this convection causes deformation of solid rocks by plastic flow. At the core-mantle boundary (CMB), 2900 km deep, seismologists have discovered...
Mineral Deformation at Earth's Core-Mantle Boundary
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Mineral Deformation at Earth's Core-Mantle Boundary Print Earth is a dynamic planet in which convection takes place on the scale of thousands of kilometers. Because Earth is mostly...
Analysis of civil aircraft propulsors with boundary layer ingestion
Hall, David Kenneth
2015-01-01
This thesis describes (i) guidelines for propulsor sizing, and (ii) strategies for fan turbomachinery conceptual design, for a boundary layer ingesting (BLI) propulsion system for advanced civil transport aircraft. For the ...
Distributed Roughness Receptivity in a Flat Plate Boundary Layer
Kuester, Matthew Scott
2014-04-18
the incoming boundary layer. This dissertation describes an experiment specifically designed to study the shielding effect. Three roughness configurations, a deterministic distributed roughness patch, a slanted rectangle, and the combination of the two, were...
Mineral Deformation at Earth's Core-Mantle Boundary
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Because Earth is mostly solid (except for its liquid-iron outer core), this convection causes deformation of solid rocks by plastic flow. At the core-mantle boundary (CMB), 2900 km...
Technology adaptation and boundary management in bona fide virtual groups.
Zhang, Huiyan
2006-04-12
and norms of media combination and media use. Group boundaries were preserved when the influence of outgroup members were constrained through media use, such as excluding them from team conference calls, filtering messages from external groups or members...
A distributed boundary detection algorithm for multi-robot systems
McLurkin, James
We describe a distributed boundary detection algorithm suitable for use on multi-robot systems with dynamic network topologies. We assume that each robot has access to its local network geometry, which is the combination ...
Uniformly Loaded Rectangular Thin Plates with Symmetrical Boundary Conditions
Milan Batista
2010-01-27
In the article the Fourier series analytical solutions of uniformly loaded rectangular thin plates with symmetrical boundary conditions are considered. For all the cases the numerical values are tabulated.
Fusion of conformal interfaces and bulk induced boundary RG flows
Anatoly Konechny
2015-09-25
We consider the basic radius changing conformal interface for a free compact boson. After investigating different theoretical aspects of this object we focus on the fusion of this interface with conformal boundary conditions. At fractions of the self-dual radius there exist exceptional D-branes. It was argued in [1] that changing the radius in the bulk induces a boundary RG flow. Following [2] we conjecture that fusing the basic radius changing interface (that changes the radius from a fraction of the self-dual radius) with the exceptional boundary conditions gives the boundary condition which is the end point of the RG flow considered in [1]. By studying the fusion singularities we recover RG logarithms and see, in particular instances, how they get resummed into power singularities. We discuss what quantities need to be calculated to gain full non-perturbative control over the fusion.
Boundary Circles of Mixed Phase Space, Hamiltonian Systems
Or Alus; Shmuel Fishman; James D. Meiss
2014-10-28
The phase space of an area-preserving map typically contains infinitely many elliptic islands embedded in a chaotic sea. Orbits near the boundary of a chaotic region have been observed to stick for long times, strongly influencing their transport properties. The boundary is composed of invariant circles, called "Boundary circles." We investigate the distribution of rotation numbers of boundary circles for the Henon quadratic map and show that the probability of occurrence of small elements of their continued fraction expansions is larger than would be expected for a number chosen at random. However, large elements occur with probabilities distributed proportionally to the random case. These results have implications for models of transport in mixed phase space.
Atomic Scale Details of Defect-Boundary Interactions
Chen, Di
2014-12-18
The study is aimed to understand atomic scale details of defect-boundary interactions, which are critical to develop radiation tolerant fuel cladding materials for harsher neutron environments. By means of molecular dynamics simulations, we...
Interaction between surface and atmosphere in a convective boundary layer /
Garai, Anirban
2013-01-01
of cold fluid constitute most of the heat transport andevent cold air descends to the ground, heat transport fromcold air during sweep events. The convective boundary layer has a great influence on moisture transport,
Computation of Mixed Type Functional Differential Boundary Value Problems
Abell, Kate A.; Elmer, Christopher E.; Humphries, A. R.; Van Vleck, Erik
2005-09-05
We study boundary value differential-difference equations where the difference terms may contain both advances and delays. Special attention is paid to connecting orbits, in particular to the modeling of the tails after ...
Grain boundary relaxation strengthening of nanocrystalline Ni–W alloys
Rupert, Timothy J.
The hardening effect caused by the relaxation of nonequilibrium grain boundary structure has been explored in nanocrystalline Ni–W alloys. First, the kinetics of relaxation hardening are studied, showing that higher annealing ...
Eddy-mean flow interactions in western boundary current jets
Waterman, Stephanie N
2009-01-01
This thesis examines the nature of eddy-mean flow interactions in western boundary current jets and recirculation gyre dynamics from both theoretical and observational perspectives. It includes theoretical studies of ...
Fusion of conformal interfaces and bulk induced boundary RG flows
Konechny, Anatoly
2015-01-01
We consider the basic radius changing conformal interface for a free compact boson. After investigating different theoretical aspects of this object we focus on the fusion of this interface with conformal boundary conditions. At fractions of the self-dual radius there exist exceptional D-branes. It was argued in [1] that changing the radius in the bulk induces a boundary RG flow. Following [2] we conjecture that fusing the basic radius changing interface (that changes the radius from a fraction of the self-dual radius) with the exceptional boundary conditions gives the boundary condition which is the end point of the RG flow considered in [1]. By studying the fusion singularities we recover RG logarithms and see, in particular instances, how they get resummed into power singularities. We discuss what quantities need to be calculated to gain full non-perturbative control over the fusion.
Grain boundary and triple junction diffusion in nanocrystalline copper
Wegner, M. Leuthold, J.; Peterlechner, M.; Divinski, S. V.; Song, X.; Wilde, G.
2014-09-07
Grain boundary and triple junction diffusion in nanocrystalline Cu samples with grain sizes, ?d?, of ?35 and ?44?nm produced by spark plasma sintering were investigated by the radiotracer method using the {sup 63}Ni isotope. The measured diffusivities, D{sub eff}, are comparable with those determined previously for Ni grain boundary diffusion in well-annealed, high purity, coarse grained, polycrystalline copper, substantiating the absence of a grain size effect on the kinetic properties of grain boundaries in a nanocrystalline material at grain sizes d???35?nm. Simultaneously, the analysis predicts that if triple junction diffusion of Ni in Cu is enhanced with respect to the corresponding grain boundary diffusion rate, it is still less than 500?D{sub gb} within the temperature interval from 420?K to 470?K.
Numerical simulations of supercell interactions with thermal boundaries
Kay, Michael Paul
1999-01-01
to examine the effects of the interaction of simulated supercede thunderstorms with thermal boundaries on storm morphology and low-level rotation. This study differs from previous supercede modeling studies that use homogeneous initial conditions. A non...
Direct imaging of enhanced current collection on grain boundaries of Cu(In,Ga)Se{sub 2} solar cells
Kim, JunHo; Kim, SeongYeon; Jiang, Chun-Sheng; Ramanathan, Kannan; Al-Jassim, Mowafak M.
2014-02-10
We report on direct imaging of current collection by performing conductive atomic force microscopy (C-AFM) measurement on a complete Cu(In,Ga)Se{sub 2} solar cell. The localized current was imaged by milling away the top conductive layer of the device by repeated C-AFM scans. The result exhibits enhanced photocurrent collection on grain boundaries (GBs) of CIGS films, consistent with the argument for electric-field-assisted carrier collection on the GBs.
Flavor twisted boundary conditions in the Breit frame
Jiang, F.-J.; Tiburzi, B. C.
2008-08-01
We use a generalization of chiral perturbation theory to account for the effects of flavor twisted boundary conditions in the Breit frame. The relevant framework for two light flavors is an SU(6|4) partially quenched theory, where the extra valence quarks differ only by their boundary conditions. Focusing on the pion electromagnetic form factor, finite volume corrections are calculated at next-to-leading order in the chiral expansion and are estimated to be small on current lattices.
Kansa, E., E-mail: edwardjkansa@netzero.com [Computational Sciences, LLC, 8000 Madison Blvd., Madison, AL 35758-2035 (United States); Shumlak, U., E-mail: shumlak@uw.edu [Computational Sciences, LLC, 8000 Madison Blvd., Madison, AL 35758-2035 (United States); Aerospace and Energetics Research Program, University of Washington, Box 352250, Seattle, WA 98195 (United States); Tsynkov, S., E-mail: tsynkov@math.ncsu.edu [Computational Sciences, LLC, 8000 Madison Blvd., Madison, AL 35758-2035 (United States); Department of Mathematics, North Carolina State University, Box 8205, Raleigh, NC 27695 (United States)
2013-02-01
Confining dense plasma in a field reversed configuration (FRC) is considered a promising approach to fusion. Numerical simulation of this process requires setting artificial boundary conditions (ABCs) for the magnetic field because whereas the plasma itself occupies a bounded region (within the FRC coils), the field extends from this region all the way to infinity. If the plasma is modeled using single fluid magnetohydrodynamics (MHD), then the exterior magnetic field can be considered quasi-static. This field has a scalar potential governed by the Laplace equation. The quasi-static ABC for the magnetic field is obtained using the method of difference potentials, in the form of a discrete Calderon boundary equation with projection on the artificial boundary shaped as a parallelepiped. The Calderon projection itself is computed by convolution with the discrete fundamental solution on the three-dimensional Cartesian grid.
Biofuel Boundaries: Estimating the Medium-Term Supply Potential of Domestic Biofuels
Jones, Andrew; O'Hare, Michael; Farrell, Alexander
2007-01-01
Biofuel Boundaries: Estimating the Medium-Term SupplyAugust 22, 2007 Biofuel Boundaries: Estimating the Medium-significant amount of liquid biofuel (equivalent to 30-100%
D. Gottschalk; A. McBride; B. D. Reddy; A. Javili; P. Wriggers; C. B. Hirschberger
2015-05-06
A detailed theoretical and numerical investigation of the infinitesimal single-crystal gradient plasticity and grain-boundary theory of Gurtin (2008) "A theory of grain boundaries that accounts automatically for grain misorientation and grain-boundary orientation". Journal of the Mechanics and Physics of Solids 56 (2), 640-662, is performed. The governing equations and flow laws are recast in variational form. The associated incremental problem is formulated in minimization form and provides the basis for the subsequent finite element formulation. Various choices of the kinematic measure used to characterize the ability of the grain boundary to impede the flow of dislocations are compared. An alternative measure is also suggested. A series of three-dimensional numerical examples serve to elucidate the theory.
Andrey Piatnitski; Volodymyr Rybalko
2010-06-03
The paper deals with homogenization problem for nonlinear elliptic and parabolic equations in a periodically perforated domain, a nonlinear Fourier boundary conditions being imposed on the perforation border. Under the assumptions that the studied differential equation satisfies monotonicity and 2-growth conditions and that the coefficient of the boundary operator is centered at each level set of unknown function, we show that the problem under consideration admits homogenization and derive the effective model.
Piatnitski, Andrey
2010-01-01
The paper deals with homogenization problem for nonlinear elliptic and parabolic equations in a periodically perforated domain, a nonlinear Fourier boundary conditions being imposed on the perforation border. Under the assumptions that the studied differential equation satisfies monotonicity and 2-growth conditions and that the coefficient of the boundary operator is centered at each level set of unknown function, we show that the problem under consideration admits homogenization and derive the effective model.
Extended self-similarity of atmospheric boundary layer wind fields in mesoscale regime: Is it real?
Kiliyanpilakkil, V P
2015-01-01
In this letter, we study the scaling properties of multi-year observed and atmospheric model-generated wind time series. We have found that the extended self-similarity holds for the observed series, and remarkably, the scaling exponents corresponding to the meoscale range closely match the well-accepted inertial-range turbulence values. However, the scaling results from the simulated time series are significantly different.
Field boundary layer characteristics as modified by clams in habitats of varying survival rates
de-spiked - Wave energy removed Flow Direction Buried Clams ADV ADV x y z Mud and Sand Flats: High.K. Delavan*, D.R. Webster *gth900g@mail.gatech.edu, dwebster@ce.gatech.edu Georgia Institute of Technology
Transport in a field aligned magnetized plasma/neutral gas boundary: the end of the plasma
Cooper, Christopher M.
2012-01-01
depending only on the initial condition velocity, v pso .supersonic solutions where |v pso | > c s are non-physicalin this model. For c s > v pso > v c the plasma velocity
The boundary rigidity problem in the presence of a magnetic field
Energy estimates method. 25. 5.1. Semibasic tensor .... The function A(x, y) is referred to as Ma˜né's action potential (of energy 1/2), and we call the ...... direct differentiation shows that (Pu)j = ??j u ? ?j?i??i u + ?ju, and the first order part is clearly tangent to ...... Now, the claim follows from Lyapunov's inequality [16, p. 346]. D ...
Kumar Awasthi, Mukesh, E-mail: mukeshiitr.kumar@gmail.com [Department of Mathematics, University of Petroleum and Energy Studies, Dehradun (India)
2014-03-15
We study the linear magnetohydrodynamic Kelvin–Helmholtz instability of the interface between two viscous, incompressible, and electrically conducting fluids. The phases are enclosed between two coaxial cylindrical porous layers with the interface through which mass and heat transfer takes place. The fluids are subjected to a constant magnetic field parallel to the streaming direction, and the suction/injection velocities for the fluids at the permeable boundaries are also taken into account. Here, we use an irrotational theory in which the motion and pressure are irrotational, and the viscosity enters through the jump in the viscous normal stress in the normal stress balance at the interface. We consider both asymmetric and axisymmetric disturbances in our analysis. A quadratic dispersion relation is deduced and stability criterion is given in terms of a critical value of relative velocity, as well as, magnetic field. It has been observed that in the case of permeable boundaries, heat and mass transfer phenomena play a dual in the stability analysis. The flow through porous medium is more stable than the pure flow.
Goyal, Amit [ORNL; Field, Dr. David [Washington State University; Held, R. [Institute of Physics, Augsburg University, Augsburg, Germany; Mannhart, J. [Institute of Physics, Augsburg University, Augsburg, Germany
2011-01-01
Grain boundaries (GBs) in high-temperature superconductors suppress the critical current density (Jc) dramatically [1-3]. The Jc drops exponentially when GB-misorientation exceeds 4 [3]. To reduce the number of high-angle GBs, fabrication of biaxially-textured, superconducting wires via epitaxial growth on cube-textured metals has been widely investigated [4-6]. Such wires have exhibited very high-Jc in applied magnetic fields despite having a majority of GBs with total misorientations greater than 4 . Here we show that GB networks in these wires have numerous GBs with out-of-plane misorientations > 4 and few boundaries having in-plane misorientations > 4 . The high performance can be explained if the Jc is determined primarily by in-plane misorientations. This supposition was confirmed by in-field transport measurements on artificially fabricated bicrystals of superconductors having only out-of-plane misorientations. Atomic resolution imaging of bicrystals with out-of-plane misorientations show that superconducting ab-planes are continuous across such GBs in contrast to GBs with in-plane misorientations.
THE SIMULATION OF FINE SCALE NOCTURNAL BOUNDARY LAYER MOTIONS WITH A MESO-SCALE ATMOSPHERIC MODEL
Werth, D.; Kurzeja, R.; Parker, M.
2009-04-02
A field project over the Atmospheric Radiation Measurement-Clouds and Radiation Testbed (ARM-CART) site during a period of several nights in September, 2007 was conducted to explore the evolution of the low-level jet (LLJ). Data was collected from a tower and a sodar and analyzed for turbulent behavior. To study the full range of nocturnal boundary layer (NBL) behavior, the Regional Atmospheric Modeling System (RAMS) was used to simulate the ARM-CART NBL field experiment and validated against the data collected from the site. This model was run at high resolution, and is ideal for calculating the interactions among the various motions within the boundary layer and their influence on the surface. The model reproduces adequately the synoptic situation and the formation and dissolution cycles of the low-level jet, although it suffers from insufficient cloud production and excessive nocturnal cooling. The authors suggest that observed heat flux data may further improve the realism of the simulations both in the cloud formation and in the jet characteristics. In a higher resolution simulation, the NBL experiences motion on a range of timescales as revealed by a wavelet analysis, and these are affected by the presence of the LLJ. The model can therefore be used to provide information on activity throughout the depth of the NBL.
Fast wave evanescence in filamentary boundary plasmas
Myra, J. R. [Lodestar Research Corporation, Boulder, Colorado 80027 (United States)] [Lodestar Research Corporation, Boulder, Colorado 80027 (United States)
2014-02-15
Radio frequency waves for heating and current drive of plasmas in tokamaks and other magnetic confinement devices must first traverse the scrape-off-layer (SOL) before they can be put to their intended use. The SOL plasma is strongly turbulent and intermittent in space and time. These turbulent properties of the SOL, which are not routinely taken into account in wave propagation codes, can have an important effect on the coupling of waves through an evanescent SOL or edge plasma region. The effective scale length for fast wave (FW) evanescence in the presence of short-scale field-aligned filamentary plasma turbulence is addressed in this paper. It is shown that although the FW wavelength or evanescent scale length is long compared with the dimensions of the turbulence, the FW does not simply average over the turbulent density; rather, the average is over the exponentiation rate. Implications for practical situations are discussed.
Microsoft Word - CADD Outline .doc
National Nuclear Security Administration (NNSA)
further information."** All Final Documents must include an Appendix with the Nevada Division of Environmental Protection Comment Response Sheets Library Distribution List ** Note...
COURSE OUTLINE 1. Calendar Information
Course Coordinator Section Name Phone Office Email Dr. Yingxu Wang 403 220-6141 ICT 542 yingxu Email L01 Dr. Yingxu Wang 403 220-6141 ICT 542 yingxu@ucalgary.ca L02 Dr. Vassil S. Dimitrov 403 210
NATIONAL RENEWABLE ENERGY LABORATORY Outline
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious RankADVANCED MANUFACTURING OFFICESpecialAPPENDIX FOrigin of Contamination inEnergy NARUCGreen NATIONAL
DROPOUTS IN SOLAR ENERGETIC PARTICLES: ASSOCIATED WITH LOCAL TRAPPING BOUNDARIES OR CURRENT SHEETS?
Seripienlert, A.; Ruffolo, D.; Matthaeus, W. H.; Chuychai, P. E-mail: scdjr@mahidol.ac.t E-mail: piyanate@gmail.co
2010-03-10
In recent observations by the Advanced Composition Explorer, the intensity of solar energetic particles exhibits sudden, large changes known as dropouts. These have been explained in terms of turbulence or a flux tube structure in the solar wind. Dropouts are believed to indicate filamentary magnetic connection to a localized particle source near the solar surface, and computer simulations of a random-phase model of magnetic turbulence have indicated a spatial association between dropout features and local trapping boundaries (LTBs) defined for a two-dimensional (2D) + slab model of turbulence. Previous observations have shown that dropout features are not well associated with sharp magnetic field changes, as might be expected in the flux tube model. Random-phase turbulence models do not properly treat sharp changes in the magnetic field, such as current sheets, and thus cannot be tested in this way. Here, we explore the properties of a more realistic magnetohydrodynamic (MHD) turbulence model (2D MHD), in which current sheets develop and the current and magnetic field have characteristic non-Gaussian statistical properties. For this model, computer simulations that trace field lines to determine magnetic connection from a localized particle source indicate that sharp particle gradients should frequently be associated with LTBs, sometimes with strong 2D magnetic fluctuations, and infrequently with current sheets. Thus, the 2D MHD + slab model of turbulent fluctuations includes some realistic features of the flux tube view and is consistent with the lack of an observed association between dropouts and intense magnetic fields or currents.
Oil and gas field code master list 1997
1998-02-01
The Oil and Gas Field Code Master List 1997 is the sixteenth annual listing of all identified oil and gas fields in the US. It is updated with field information collected through October 1997. The purpose of this publication is to provide unique, standardized codes for identification of domestic fields. Use of these field codes fosters consistency of field identification by government and industry. As a result of their widespread adoption they have in effect become a national standard. The use of field names and codes listed in this publication is required on survey forms and other reports regarding field-specific data collected by EIA. There are 58,366 field records in this year`s FCML, 437 more than last year. The FCML includes: field records for each State and county in which a field resides; field records for each offshore area block in the Gulf of Mexico in which a field resides; field records for each alias field name (definition of alias is listed); fields crossing State boundaries that may be assigned different names by the respective State naming authorities. This report also contains an Invalid Field Record List of 4 records that have been removed from the FCML since last year`s report. These records were found to be either technically incorrect or to represent field names which were never recognized by State naming authorities.
Pseudo Limits, Biadjoints, and Pseudo Algebras: Categorical Foundations of Conformal Field Theory
Thomas M. Fiore
2006-10-18
In this paper I develop categorical foundations needed for a rigorous approach to the definition of conformal field theory outlined by Graeme Segal. I discuss pseudo algebras over theories and 2-theories, their pseudo morphisms, bilimits, bicolimits, biadjoints, stacks, and related concepts.
Bilski, P; D'Errico, F; Esposito, A; Fehrenbacher, G; Fernàndez, F; Fuchs, A; Golnik, N; Lacoste, V; Leuschner, A; Sandri, S; Silari, M; Spurny, F; Wiegel, B; Wright, P
2006-01-01
This report outlines the research needs and research activities within Europe to develop new and improved methods and techniques for the characterization of complex radiation fields at workplaces around high-energy accelerators and the next generation of thermonuclear fusion facilities under the auspices of the COordinated Network for RAdiation Dosimetry (CONRAD) project funded by the European Commission.
Dipole tilt angle effects on the latitude of the cusp and cleft/low-latitude boundary layer
Newell, P.T.; Meng, C.I. (Johns Hopkins Univ., Laurel, MD (USA))
1989-06-01
A large data set of approximately 12,000 Defense Meteorological Satellite Program satellite F7 crossings of the cusp or the cleft (i.e., the dayside magnetospheric boundary layer) over a 3-year period is studied for seasonal dependence in latitudinal position. A carefully tested algorithm is used to distinguish the various dayside particle precipitation regions and boundaries. It is found that in the 1,100-1,300 MLT sector, the cusp proper exhibits about {minus}0.06{degree} magnetic latitude (MLAT) shift for each degree increase in dipole tilt angle. Thus the difference between the average summer and winter cusp positions is close to 4{degree} MLAT, approximately symmetric about equinox. For the cleft (magnetospheric boundary layer) the variation is smaller. For example, in the 0700-0900 MLT sector the cleft equatorward boundary shift is {minus} 0.027{degree} MLAT/1{degree} dipole tilt. These results are in general agreement with the predictions of empirical magnetospheric magnetic field models. Various ground-based and low-altitude observations can be systematically affected by the seasonal latitudinal shift herein documented.
Electric and Magnetic Fields Facts
2006-08-01
This discussion outlines the EMF issue, summarizes the research conducted to date, and describes what Western Area Power Administration is doing to address concerns about EMF.
Structure and Chemistry of Yttria-Stabilized Cubic-Zirconia Symmetric Tilt Grain Boundaries
Pennycook, Steve
Structure and Chemistry of Yttria-Stabilized Cubic-Zirconia Symmetric Tilt Grain Boundaries boundaries in yttria-stabilized cubic-zirconia, 5 (310) and near- 13 (510), are studied by Z [001] symmetric tilt grain boundaries in yttria-stabilized cubic-zirconia (YSZ). The grain boundaries
Graphene as a Lattice Field Theory
Simon Hands; Wes Armour; Costas Strouthos
2015-01-08
We introduce effective field theories for the electronic properties of graphene in terms of relativistic fermions propagating in 2+1 dimensions, and outline how strong inter-electron interactions may be modelled by numerical simulation of a lattice field theory. For strong enough coupling an insulating state can form via condensation of particle-hole pairs, and it is demonstrated that this is a theoretical possibility for monolayer graphene. For bilayer graphene the effect of an interlayer bias voltage can be modelled by the introduction of a chemical potential (akin to isopsin chemical potential in QCD) with no accompanying sign problem; simulations reveal the presence of strong interactions among the residual degrees of freedom at the resulting Fermi surface, which is disrupted by an excitonic condensate. We also present preliminary results for the quasiparticle dispersion, which permit direct estimates of both the Fermi momentum and the induced gap.
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Adding Gauge Fields to Kaplan's Fermions
T. Blum; Leo Karkkainen
1993-12-10
We experiment with adding dynamical gauge field to Kaplan (defect) fermions. In the case of U(1) gauge theory we use an inhomogenous Higgs mechanism to restrict the 3d gauge dynamics to a planar 2d defect. In our simulations the 3d theory produce the correct 2d gauge dynamics. We measure fermion propagators with dynamical gauge fields. They posses the correct chiral structure. The fermions at the boundary of the support of the gauge field (waveguide) are non-chiral, and have a mass two times heavier than the chiral modes. Moreover, these modes cannot be excited by a source at the defect; implying that they are dynamically decoupled. We have also checked that the anomaly relation is fullfilled for the case of a smooth external gauge field. This is an uuencoded ps-file. Use 'uudecode hepchiral.ps.Z' and 'uncompress hepchiral.ps.Z' to produce the psfile.
A Computational Model for Sound Field Absorption by Acoustic Arrays
. We then formulate the acoustic wave equation with the absorption boundary coeÆcient in the frequency the sound absorption property of arrays of micro-acoustic actuators at a control surface. We use the waveA Computational Model for Sound Field Absorption by Acoustic Arrays H. T. Banks #3; D. G. Cole z K
Nonlinear electric field structures in the inner magnetosphere
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Malaspina, D. M.; Andersson, L.; Ergun, R. E.; Wygant, J. R.; Bonnell, J. W.; Kletzing, C.; Reeves, G. D.; Skoug, R. M.; Larsen, B. A.
2014-08-28
Recent observations by the Van Allen Probes spacecraft have demonstrated that a variety of electric field structures and nonlinear waves frequently occur in the inner terrestrial magnetosphere, including phase space holes, kinetic field-line resonances, nonlinear whistler-mode waves, and several types of double layer. However, it is nuclear whether such structures and waves have a significant impact on the dynamics of the inner magnetosphere, including the radiation belts and ring current. To make progress toward quantifying their importance, this study statistically evaluates the correlation of such structures and waves with plasma boundaries. A strong correlation is found. These statistical results, combinedmore »with observations of electric field activity at propagating plasma boundaries, are consistent with the identification of these boundaries as the source of free energy responsible for generating the electric field structures and nonlinear waves of interest. Therefore, the ability of these structures and waves to influence plasma in the inner magnetosphere is governed by the spatial extent and dynamics of macroscopic plasma boundaries in that region.« less
Nonlinear electric field structures in the inner magnetosphere
Malaspina, D. M.; Andersson, L.; Ergun, R. E.; Wygant, J. R.; Bonnell, J. W.; Kletzing, C.; Reeves, G. D.; Skoug, R. M.; Larsen, B. A.
2014-08-28
Recent observations by the Van Allen Probes spacecraft have demonstrated that a variety of electric field structures and nonlinear waves frequently occur in the inner terrestrial magnetosphere, including phase space holes, kinetic field-line resonances, nonlinear whistler-mode waves, and several types of double layer. However, it is nuclear whether such structures and waves have a significant impact on the dynamics of the inner magnetosphere, including the radiation belts and ring current. To make progress toward quantifying their importance, this study statistically evaluates the correlation of such structures and waves with plasma boundaries. A strong correlation is found. These statistical results, combined with observations of electric field activity at propagating plasma boundaries, are consistent with the identification of these boundaries as the source of free energy responsible for generating the electric field structures and nonlinear waves of interest. Therefore, the ability of these structures and waves to influence plasma in the inner magnetosphere is governed by the spatial extent and dynamics of macroscopic plasma boundaries in that region.
Effective velocity boundary condition at a mixed slip surface
Sbragaglia, M
2006-01-01
This paper studies the nature of the effective velocity boundary conditions for liquid flow over a plane boundary on which small free-slip islands are randomly distributed. It is found that, to lowest order in the area fraction $\\beta$ covered by free-slip regions with characteristic size $a$, a macroscopic Navier-type slip condition emerges with a slip length of the order of $a\\beta$. The study is motivated by recent experiments which suggest that gas nano-bubbles may form on solid walls and may be responsible for the appearance of a partial slip boundary conditions for liquid flow. The results are also relevant for ultra-hydrophobic surfaces exploiting the so-called ``lotus effect''.
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.
Experimental studies of pedestrian flows under different boundary conditions
Zhang, Jun
2015-01-01
In this article the dynamics of pedestrian streams in four different scenarios are compared empirically to investigate the influence of boundary conditions on it. The Voronoi method, which allows high resolution and small fluctuations of measured density in time and space, is used to analyze the experiments. It is found that pedestrian movement in systems with different boundary conditions (open, periodic boundary conditions and outflow restrained) presents various characteristics especially when the density is larger than 2 m-2. In open corridor systems the specific flow increases continuously with increasing density till 4 m-2. The specific flow keeps constant in systems with restrained outflow, whereas it decreases from 1 (m.s)-1 to zero in system with closed periodical condition.
Edge Plasma Boundary Layer Generated By Kink Modes in Tokamaks
L.E. Zakharov
2010-11-22
This paper describes the structure of the electric current generated by external kink modes at the plasma edge using the ideally conducting plasma model. It is found that the edge current layer is created by both wall touching and free boundary kink modes. Near marginal stability, the total edge current has a universal expression as a result of partial compensation of the ?-functional surface current by the bulk current at the edge. The resolution of an apparent paradox with the pressure balance across the plasma boundary in the presence of the surface currents is provided.
Boundary conditions control for a Shallow-Water model
Kazantsev, Eugene
2012-01-01
A variational data assimilation technique was used to estimate optimal discretization of interpolation operators and derivatives in the nodes adjacent to the rigid boundary. Assimilation of artificially generated observational data in the shallow-water model in a square box and assimilation of real observations in the model of the Black sea are discussed. It is shown in both experiments that controlling the discretization of operators near a rigid boundary can bring the model solution closer to observations as in the assimilation window and beyond the window. This type of control allows also to improve climatic variability of the model.
Gradient zone boundary control in salt gradient solar ponds
Hull, John R. (Downers Grove, IL)
1984-01-01
A method and apparatus for suppressing zone boundary migration in a salt gradient solar pond includes extending perforated membranes across the pond at the boundaries, between the convective and non-convective zones, the perforations being small enough in size to prevent individual turbulence disturbances from penetrating the hole, but being large enough to allow easy molecular diffusion of salt thereby preventing the formation of convective zones in the gradient layer. The total area of the perforations is a sizable fraction of the membrane area to allow sufficient salt diffusion while preventing turbulent entrainment into the gradient zone.
Polymer Effects on Heat Transport in Laminar Boundary Layer Flow
Roberto Benzi; Emily S. C. Ching; Vivien W. S. Chu
2011-04-27
We consider a laminar Blasius boundary-layer flow above a slightly heated horizontal plate and study the effect of polymer additives on the heat transport. We show that the action of the polymers can be understood as a space-dependent effective viscosity that first increases from the zero-shear value then decreases exponentially back to the zero-shear value as one moves away from the boundary. We find that with such an effective viscosity, both the horizontal and vertical velocities near the plate are decreased thus leading to an increase in the friction drag and a decrease in the heat transport in the flow.
Humphreys, Eugene
, Transcontinental arch, and Yavapai Mazatzal province boundary), suggesting that older boundaries influenced
Gorshkov, Aleksei V [M. V. Lomonosov Moscow State University, Faculty of Mechanics and Mathematics, Moscow (Russian Federation)
2012-09-30
The problem of stabilizing a solution of the 2D Navier-Stokes system defined in the exterior of a bounded domain with smooth boundary is investigated. For a given initial velocity field a control on the boundary of the domain must be constructed such that the solution stabilizes to a prescribed vortex solution or trivial solution at the rate of 1/t{sup k}. On the way, related questions are investigated, concerning the behaviour of the spectrum of an operator under a relatively compact perturbation and the existence of attracting invariant manifolds. Bibliography: 21 titles.
Static plane symmetric relativistic fluids and empty repelling singular boundaries
Ricardo E. Gamboa Saravi
2007-12-18
We present a detailed analysis of the general exact solution of Einstein's equation corresponding to a static and plane symmetric distribution of matter with density proportional to pressure. We study the geodesics in it and we show that this simple spacetime exhibits very curious properties. In particular, it has a free of matter repelling singular boundary and all geodesics bounce off it.
Modeling of dislocationgrain boundary interactions in FCC metals
Cai, Wei
- dynamics simulations (DD). The conceptual approach to be followed for single-crystal plasticity is straight using atomistic methods. For polycrystal plasticity, however, the prob- lem is significantly more complex due to the role of grain boundaries (GB) in plastic deformation. While the in- teractions between
Extending Boundaries with Meta-Design and Cultures of Participation
Fischer, Gerhard
urban planning problems, (3) modeling the buildings of the world in 3D, and (4) using Smart Grids to support energy sustainability. These examples show how meta- design and cultures of participation of participation, systemic problems, boundaries, distances, motivation, control, socio-technical environments ACM
Measurements of grain boundary properties in nanocrystalline ceramics
Chiang, Y.M.; Smyth, I.P.; Terwilliger, C.D. (Massachusetts Inst. of Tech., Cambridge, MA (USA). Dept. of Materials Science and Engineering); Petuskey, W.T. (Arizona State Univ., Tempe, AZ (USA). Dept. of Chemistry); Eastman, J.A. (Argonne National Lab., IL (USA))
1990-11-01
The advent of nanocrystalline ceramics prepared by a variety of solution-chemical and vapor deposition methods offers a unique opportunity for the determination grain boundary properties by bulk'' thermodynamic methods. In this paper we discuss results from two types of measurements on model nanocrystalline ceramics. The first is a solution thermodynamic measurement of the activity of nanocrystalline SiC in polycarbosilane-derived silicon carbide fibers (Nicalon). Structural studies have shown that Nicalon consists of well-ordered cubic ({beta} or 3C polytype) SiC grains separated by a very thin grain boundary layer (<1 nm thick) containing the oxygen. The physical properties and chemical reactivity of these fibers are distinctly different from that of bulk silicon carbide. Direct measurement of the alloy composition and analysis of the microstructure has allowed the dissolution reaction to be identified and a lower limit for the SiC activity in the nanocrystalline form to be determined. A second method of measuring grain boundary properties we have investigated for nanocrystalline Si and TiO{sub 2} is high temperature calorimetry. In appropriate samples the grain boundary enthalpy can be measured through the heat evolved during grain growth. Preliminary results on nanocrystalline Si prepared by the recrystallization of amorphous evaporated films and on TiO{sub 2} condensed from the vapor phase are discussed. 29 refs., 3 figs., 1 tab.
PPRODO: Prediction of Protein Domain Boundaries Using Neural Networks
Lee, Jooyoung
PPRODO: Prediction of Protein Domain Boundaries Using Neural Networks Jaehyun Sim, Seung-Yeon Kim-BLAST. A 10-fold cross-validation technique is performed to obtain the parameters of neural networks using; neural network INTRODUCTION Domains are semi-independent 3-dimensional (3D) units in proteins, and often
Subjective surfaces: a geometric model for boundary completion
Sarti, Alessandro; Malladi, Ravi; Sethian, J.A.
2000-06-01
We present a geometric model and a computational method for segmentation of images with missing boundaries. In many situations, the human visual system fills in missing gaps in edges and boundaries, building and completing information that is not present. Boundary completion presents a considerable challenge in computer vision, since most algorithms attempt to exploit existing data. A large body of work concerns completion models, which postulate how to construct missing data; these models are often trained and specific to particular images. In this paper, we take the following, alternative perspective: we consider a reference point within an image as given, and then develop an algorithm which tries to build missing information on the basis of the given point of view and the available information as boundary data to the algorithm. Starting from this point of view, a surface is constructed. It is then evolved with the mean curvature flow in the metric induced by the image until a piecewise constant solution is reached. We test the computational model on modal completion, amodal completion, texture, photo and medical images. We extend the geometric model and the algorithm to 3D in order to extract shapes from low signal/noise ratio medical volumes. Results in 3D echocardiography and 3D fetal echography are presented.
A Navier boundary value problem for Willmore surfaces of revolution #
Grunau, Hans-Christoph
A Navier boundary value problem for Willmore surfaces of revolution # Klaus Deckelnick + and Hans Forschungsgemeinschaft (DFG) is gratefully acknowledged + eÂmail: Klaus.Deckelnick@ovgu.de # eÂmail: Hans of closed Willmore surfaces of prescribed genus was proved by Simon [Sn] and Bauer & Kuwert [BK]. Con
Boundary value problems for the onedimensional Willmore equation
Grunau, Hans-Christoph
Boundary value problems for the oneÂdimensional Willmore equation Klaus Deckelnick # and Hans--known that the corresponding surface # has to satisfy the Willmore equation #H + 2H(H 2 -K) = 0 on #, (1) # eÂmail: Klaus Willmore surfaces of prescribed genus has been proved by Simon [Sn] and Bauer & Kuwert [BK]. Also, local
Boundary value problems for the one-dimensional Willmore equation
Grunau, Hans-Christoph
Boundary value problems for the one-dimensional Willmore equation Klaus Deckelnick and HansÂknown that the corresponding surface has to satisfy the Willmore equation H + 2H(H2 - K) = 0 on , (1) e-mail: Klaus Willmore surfaces of prescribed genus has been proved by Simon [Sn] and Bauer & Kuwert [BK]. Also, local
NASA/TM2014218280 Analysis of Well-Clear Boundary
Muñoz, César A.
NASA/TM2014218280 Analysis of Well-Clear Boundary Models for the Integration of UAS in the NAS Research Center, Hampton, Virginia June 2014 #12;NASA STI Program . . . in Profile Since its founding, NASA has been dedicated to the advancement of aeronautics and space science. The NASA scientific
Zoning boundaries can make good neighbors in conservation
Zoning boundaries can make good neighbors in conservation A panda with a GPS collar in the Wolong changes might be needed." A unique case study that does of one of the world's renowned nature reserves giant panda census, geographic data on locations of roads and human establishments, and new data
well posedness of Hyperbolic Initial Boundary Value Problems
MÃ©tivier, Guy
direction, we show on an example that, even for symmetric systems in the sense of Friedrichs, with variable and the class M . . . . . . . . . . . . . . . . . 11 2.3 The incoming bundle, block decomposition and if the boundary condition is maximal 2 #12;strictly dissipative , then for all T 0, u0 L2(Rd), f L1([0, T]; L2
Meta-Design: Expanding Boundaries and Redistributing Control in Design
Fischer, Gerhard
Meta-Design: Expanding Boundaries and Redistributing Control in Design Gerhard Fischer Center for Lifelong Learning and Design University of Colorado, Boulder http://l3d.cs.colorado.edu/~gerhard/ Abstract. Meta-design is an emerging conceptual framework aimed at defining and creating socio
UNCORRECTED 2 Multiscale boundary conditions in crystalline solids
Qian, Dong
UNCORRECTED PROOF 1 2 Multiscale boundary conditions in crystalline solids: 3 Theory scale simulations of crystalline solids. Based on Fourier analysis of regular lattices structures with a crystalline gold substrate. Complete atomistic resolution on the coarse grain is alternatively 19 employed
Radiating Instability of a Meridional Boundary Current HRISTINA G. HRISTOVA
energy away from the source of instability. It can be contrasted with a trapped instability ocean basins. Un- stable boundary currents can be an important source of eddy kinetic energy. Radiating instabilities propagate energy away from the locally unstable region by coupling to the free
Two-Baryon Systems with Twisted Boundary Conditions
Zohreh Davoudi
2014-11-07
I derive the most general quantization condition for energy eigenvalues of two interacting baryons in a finite cubic volume when arbitrary twisted boundary conditions are imposed on their finite-volume wavefunctions. These quantization conditions are used, along with experimentally known scattering parameters of two-nucleon systems in the coupled 3S1-3D1 channels, to demonstrate the expected effect of a selection of twisted boundary conditions on the spectrum of the deuteron. It is shown that an order of magnitude reduction in the finite-volume corrections to the deuteron binding energy arise in moderate volumes with a proper choice of boundary conditions on the proton and the neutron, or by averaging the result of periodic and anti-periodic boundary conditions. These observations mean that a sub-percent accuracy can be achieved in the determination of the deuteron binding energy at (spatial) volumes as small as ~(9[fm])^3 in upcoming lattice QCD calculations of this nucleus with physical light-quark masses. The results reviewed in this talk are presented in details in Ref. [1].
Boundary Integral Methods for Multicomponent Fluids and Multiphase Materials
. An important and complicating property of such systems is surface tension (or surface energy in the materials of Mathematical Sciences, New York University, New York, NY 10012. 1 #12;governing the bulk fluid or materialBoundary Integral Methods for Multicomponent Fluids and Multiphase Materials T.Y. Hou J
Stratified Flow over Topography: Wave Generation and Boundary Layer Separation
Sutherland, Bruce
Stratified Flow over Topography: Wave Generation and Boundary Layer Separation B. R. Sutherland topography. We have chosen to use periodic, finiteamplitude hills which are representative of the Earth upon internal waves generated by flow over rough topography. 1 Introduction Internal waves propagate
Stratified Flow over Topography: Wave Generation and Boundary Layer Separation
Sutherland, Bruce
Stratified Flow over Topography: Wave Generation and Boundary Layer Separation B. R. Sutherland Abstract We have performed laboratory experiments to study wave generation over and in the lee of model upon internal waves generated by flow over rough topography. 1 Introduction Internal waves propagate
An Unstable Elliptic Free Boundary Problem arising in Solid Combustion
Monneau, RÃ©gis
An Unstable Elliptic Free Boundary Problem arising in Solid Combustion R. Monneau Ecole Nationale in solid combustion. The maximal solution and every local minimizer of the energy are regular, that is, {u combustion, singularity, unstable problem, Aleksandrov reflection, unique blow-up limit, second variation
Connectivity of Confined Dense Networks: Boundary Effects and Scaling Laws
Goussev, Arseni O.
in statistical physics to analyze the effects that the boundaries of the geometry have on connectivity dense networks for each of these models. Finally, in order to demonstrate the versatility of our theory@toshiba-trel.com. #12;2 e.g., [1][3]). From a communications perspective, it is of paramount importance to understand
ORIGINAL PAPER Mechanical filtering by the boundary layer and fluidstructure
McHenry, Matt
ORIGINAL PAPER Mechanical filtering by the boundary layer and fluidstructure interaction force coefficient for fluid c speed of sound in water C integration constant Em Young's modulus moment of area k viscous drag coefficient L hydrodynamic force coefficient M bending moment N number
Ozone Chemistry in the High-Latitude Boundary Layer
Toohey, Darin W.
Ozone Chemistry in the High-Latitude Boundary Layer Linnea Avallone Department of Atmospheric layer ozone loss phenomenon · In situ observations of BrO at Arctic sites · Preliminary results from Antarctic experiments in 2002 and 2004 #12;Brief History · Springtime ozone loss observed at many sites
ROUTINE CLOUD-BOUNDARY ALGORITHM DEVELOPMENT FOR ARM MICROPULSE LIDAR
of Energy Office of Science ABSTRACT An operational cloud boundary algorithm (Wang and Sassen 2001) has been Associates, LLC under Contract No. DE-AC02- 98CH10886 with the U.S. Department of Energy. The publisher-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript
Boundary geometric control of a counter-current heat exchanger
Boyer, Edmond
Boundary geometric control of a counter-current heat exchanger Ahmed MAIDIa , Moussa DIAFb , Jean control of a counter-current heat exchanger whose control is designed considering a model based on two. The objective consists in controlling the internal fluid temperature, at the heat exchanger outlet
Mass exchange in the stable boundary layer by coherent structures
Leclerc, Monique Y.
) and a dense array of wind sensors to observe an indirect representation of roll vortices and plumes over the surface appears to pump energy near the surface thereby supporting the development of coherent structures gaseous exchange 1. Introduction Mass and energy exchange in the stable boundary layer remains poorly
NONLINEAR GEOSTROPHIC ADJUSTMENT IN THE PRESENCE OF A BOUNDARY
the initial disturbance, and Kelvin waves confined near the boundary. The theory provides simple formulae the fast-slow splitting, in spite of the fact that the frequency gap between the Kelvin waves and slow. In the case of a localised initial disturbance the total mass of the lowest-order slow component
A Theory of Spatial Regions with Indeterminate Boundaries
Leeds, University of
, School of Computer Studies, University of Leeds, Leeds, LS2 9JT, UK. email: fagc,ngottsg@scs.leeds review a first order theory of regions with crisp, well defined, boundaries. Then we present at Leeds has been to evaluate, extend and implement a theory 2 of space and time based upon Clarke
Integral Operators Basic in Random Fields Estimation Theory
Alexander Kozhevnikov; Alexander G. Ramm
2004-05-03
The paper deals with the basic integral equation of random field estimation theory by the criterion of minimum of variance of the error estimate. This integral equation is of the first kind. The corresponding integra$ operator over a bounded domain $\\Omega $ in ${\\Bbb R}^{n}$ is weakly singular. This operator is an isomorphism between appropriate Sobolev spaces. This is proved by a reduction of the integral equ$ an elliptic boundary value problem in the domain exterior to $\\Omega .$ Extra difficulties arise due to the fact that the exterior boundary value problem should be solved in the Sobolev spaces of negative order.
Optimization code with weighting function for the reconstruction of coronal magnetic fields
T. Wiegelmann
2008-02-01
We developed a code for the reconstruction of nonlinear force-free and non-force-free coronal magnetic fields. The 3D magnetic field is computed numerically with the help of an optimization principle. The force-free and non-force-free codes are compiled in one program. The force-free approach needs photospheric vector magnetograms as input. The non-force-free code additionally requires the line-of-sight integrated coronal density distribution in combination with a tomographic inversion code. Previously the optimization approach has been used to compute magnetic fields using all six boundaries of a computational box. Here we extend this method and show how the coronal magnetic field can be reconstructed only from the bottom boundary, where the boundary conditions are measured with vector magnetographs. The program is planed for use within the Stereo mission.
The Casimir effect with quantized charged spinor matter in background magnetic field
Yu. A. Sitenko
2015-05-05
We study the influence of a background uniform magnetic field and boundary conditions on the vacuum of a quantized charged spinor matter field confined between two parallel neutral plates; the magnetic field is directed orthogonally to the plates. The admissible set of boundary conditions at the plates is determined by the requirement that the Dirac Hamiltonian operator be self-adjoint. It is shown that, in the case of a sufficiently strong magnetic field and a sufficiently large separation of the plates, the generalized Casimir force is repulsive, being independent of the choice of a boundary condition, as well as of the distance between the plates. The detection of this effect seems to be feasible in the foreseeable future.
ESRM 430 Lab 7 Mobile GIS for Collecting Spatial Field Data
Brown, Sally
ESRM 430 Lab 7 Mobile GIS for Collecting Spatial Field Data Instructor: Matt Dunbar GIS Program) GIS Basics: Generalizing the Real-World using Three Data Types Point Sample Location, Tree, Bench, or Political Boundary Mobile GIS vs. GPS vs. Laser Rangefinders: Mobile GIS Field-portable Geographic
Magnetic fields in non-convective regions of stars
Braithwaite, J
2015-01-01
We review the current state of knowledge of magnetic fields inside stars, concentrating on recent developments concerning magnetic fields in stably stratified (zones of) stars, leaving out convective dynamo theories and observations of convective envelopes. We include the observational properties of A, B and O-type main-sequence stars, which have radiative envelopes, and the fossil field model which is normally invoked to explain the strong fields sometimes seen in these stars. Observations seem to show that Ap-type stable fields are excluded in stars with convective envelopes. Most stars contain both radiative and convective zones, and there are potentially important effects arising from the interaction of magnetic fields at the boundaries between them, the solar cycle being one of the better known examples. Related to this, we discuss whether the Sun could harbour a magnetic field in its core. Recent developments regarding the various convective and radiative layers near the surfaces of early-type stars and...
Chow, Fotini Katopodes
models, such as the Weather Research and Forecasting (WRF) model, are in- creasingly used for high facilitates explicit resolution of complex terrain, even urban terrain, in the WRF mesoscale model. First gradient boundary conditions. Specified diurnal heating in a valley, producing anabatic winds, is used
Tackley, Paul J.
The interaction between the post-perovskite phase change and a thermo-chemical boundary layer near convection with the newly-discovered post-perovskite (PPV) phase change are used to characterize its depth. The strongly exothermic nature of the post-perovskite phase change induces an anti
Model of the boundary layer of a vacuum-arc magnetic filter
Minotti, F.; Giuliani, L.; Grondona, D.; Della Torre, H.; Kelly, H.
2013-03-21
A model is developed to describe the electrostatic boundary layer in a positively biased magnetic filter in filtered arcs with low collisionality. The set of equations used includes the electron momentum equation, with an anomalous collision term due to micro-instabilities leading to Bohm diffusion, electron mass conservation, and Poisson equation. Analytical solutions are obtained, valid for the regimes of interest, leading to an explicit expression to determine the electron density current to the filter wall as a function of the potential of the filter and the ratio of electron density at the plasma to that at the filter wall. Using a set of planar and cylindrical probes it is verified experimentally that the mentioned ratio of electron densities remains reasonably constant for different magnetic field values and probe bias, which allows to obtain a closed expression for the current. Comparisons are made with the experimentally determined current collected at different sections of a positively biased straight filter.
Coupled Mesoscale-Large-Eddy Modeling of Realistic Stable Boundary Layer Turbulence
Wang, Yao; Manuel, Lance
2013-01-01
Site-specific flow and turbulence information are needed for various practical applications, ranging from aerodynamic/aeroelastic modeling for wind turbine design to optical diffraction calculations. Even though highly desirable, collecting on-site meteorological measurements can be an expensive, time-consuming, and sometimes a challenging task. In this work, we propose a coupled mesoscale-large-eddy modeling framework to synthetically generate site-specific flow and turbulence data. The workhorses behind our framework are a state-of-the-art, open-source atmospheric model called the Weather Research and Forecasting (WRF) model and a tuning-free large-eddy simulation (LES) model. Using this coupled framework, we simulate a nighttime stable boundary layer (SBL) case from the well-known CASES-99 field campaign. One of the unique aspects of this work is the usage of a diverse range of observations for characterization and validation. The coupled models reproduce certain characteristics of observed low-level jets....
Aleph Field Solver Challenge Problem Results Summary.
Hooper, Russell; Moore, Stan Gerald
2015-01-01
Aleph models continuum electrostatic and steady and transient thermal fields using a finite-element method. Much work has gone into expanding the core solver capability to support enriched mod- eling consisting of multiple interacting fields, special boundary conditions and two-way interfacial coupling with particles modeled using Aleph's complementary particle-in-cell capability. This report provides quantitative evidence for correct implementation of Aleph's field solver via order- of-convergence assessments on a collection of problems of increasing complexity. It is intended to provide Aleph with a pedigree and to establish a basis for confidence in results for more challeng- ing problems important to Sandia's mission that Aleph was specifically designed to address.
Lunquist, K A; Chow, F K; Lundquist, J K; Mirocha, J D
2007-09-04
Flow and dispersion processes in urban areas are profoundly influenced by the presence of buildings which divert mean flow, affect surface heating and cooling, and alter the structure of turbulence in the lower atmosphere. Accurate prediction of velocity, temperature, and turbulent kinetic energy fields are necessary for determining the transport and dispersion of scalars. Correct predictions of scalar concentrations are vital in densely populated urban areas where they are used to aid in emergency response planning for accidental or intentional releases of hazardous substances. Traditionally, urban flow simulations have been performed by computational fluid dynamics (CFD) codes which can accommodate the geometric complexity inherent to urban landscapes. In these types of models the grid is aligned with the solid boundaries, and the boundary conditions are applied to the computational nodes coincident with the surface. If the CFD code uses a structured curvilinear mesh, then time-consuming manual manipulation is needed to ensure that the mesh conforms to the solid boundaries while minimizing skewness. If the CFD code uses an unstructured grid, then the solver cannot be optimized for the underlying data structure which takes an irregular form. Unstructured solvers are therefore often slower and more memory intensive than their structured counterparts. Additionally, urban-scale CFD models are often forced at lateral boundaries with idealized flow, neglecting dynamic forcing due to synoptic scale weather patterns. These CFD codes solve the incompressible Navier-Stokes equations and include limited options for representing atmospheric processes such as surface fluxes and moisture. Traditional CFD codes therefore posses several drawbacks, due to the expense of either creating the grid or solving the resulting algebraic system of equations, and due to the idealized boundary conditions and the lack of full atmospheric physics. Meso-scale atmospheric boundary layer simulations, on the other hand, are performed by numerical weather prediction (NWP) codes, which cannot handle the geometry of the urban landscape, but do provide a more complete representation of atmospheric physics. NWP codes typically use structured grids with terrain-following vertical coordinates, include a full suite of atmospheric physics parameterizations, and allow for dynamic synoptic scale lateral forcing through grid nesting. Terrain following grids are unsuitable for urban terrain, as steep terrain gradients cause extreme distortion of the computational cells. In this work, we introduce and develop an immersed boundary method (IBM) to allow the favorable properties of a numerical weather prediction code to be combined with the ability to handle complex terrain. IBM uses a non-conforming structured grid, and allows solid boundaries to pass through the computational cells. As the terrain passes through the mesh in an arbitrary manner, the main goal of the IBM is to apply the boundary condition on the interior of the domain as accurately as possible. With the implementation of the IBM, numerical weather prediction codes can be used to explicitly resolve urban terrain. Heterogeneous urban domains using the IBM can be nested into larger mesoscale domains using a terrain-following coordinate. The larger mesoscale domain provides lateral boundary conditions to the urban domain with the correct forcing, allowing seamless integration between mesoscale and urban scale models. Further discussion of the scope of this project is given by Lundquist et al. [2007]. The current paper describes the implementation of an IBM into the Weather Research and Forecasting (WRF) model, which is an open source numerical weather prediction code. The WRF model solves the non-hydrostatic compressible Navier-Stokes equations, and employs an isobaric terrain-following vertical coordinate. Many types of IB methods have been developed by researchers; a comprehensive review can be found in Mittal and Iaccarino [2005]. To the authors knowledge, this is the first IBM approach that is able to
The origin, evolution and signatures of primordial magnetic fields
Kandaswamy Subramanian
2015-04-09
The universe is magnetized on all scales probed so far. On the largest scales, galaxies and galaxy clusters host magnetic fields at the micro Gauss level coherent on scales up to ten kpc. Recent observational evidence suggests that even the intergalactic medium in voids could host a weak $\\sim 10^{-16}$ Gauss magnetic field, coherent on Mpc scales. An intriguing possibility is that these observed magnetic fields are a relic from the early universe, albeit one which has been subsequently amplified and maintained by a dynamo in collapsed objects. We review here the origin, evolution and signatures of primordial magnetic fields. After a brief summary of magnetohydrodynamics in the expanding universe, we turn to magnetic field generation during inflation and other phase transitions. We trace the linear and nonlinear evolution of the generated primordial fields through the radiation era, including viscous effects. Sensitive observational signatures of primordial magnetic fields on the cosmic microwave background, including current constraints from Planck, are discussed. After recombination, primordial magnetic fields could strongly influence structure formation, especially on dwarf galaxy scales. The resulting signatures on reionization, the redshifted 21 cm line, weak lensing and the Lyman-$\\alpha$ forest are outlined. Constraints from radio and $\\gamma$-ray astronomy are summarized. Astrophysical batteries and the role of dynamos in reshaping the primordial field are briefly considered. The review ends with some final thoughts on primordial magnetic fields.
Observation of low magnetic field density peaks in helicon plasma
Barada, Kshitish K.; Chattopadhyay, P. K.; Ghosh, J.; Kumar, Sunil; Saxena, Y. C. [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)
2013-04-15
Single density peak has been commonly observed in low magnetic field (<100 G) helicon discharges. In this paper, we report the observations of multiple density peaks in low magnetic field (<100 G) helicon discharges produced in the linear helicon plasma device [Barada et al., Rev. Sci. Instrum. 83, 063501 (2012)]. Experiments are carried out using argon gas with m = +1 right helical antenna operating at 13.56 MHz by varying the magnetic field from 0 G to 100 G. The plasma density varies with varying the magnetic field at constant input power and gas pressure and reaches to its peak value at a magnetic field value of {approx}25 G. Another peak of smaller magnitude in density has been observed near 50 G. Measurement of amplitude and phase of the axial component of the wave using magnetic probes for two magnetic field values corresponding to the observed density peaks indicated the existence of radial modes. Measured parallel wave number together with the estimated perpendicular wave number suggests oblique mode propagation of helicon waves along the resonance cone boundary for these magnetic field values. Further, the observations of larger floating potential fluctuations measured with Langmuir probes at those magnetic field values indicate that near resonance cone boundary; these electrostatic fluctuations take energy from helicon wave and dump power to the plasma causing density peaks.
Deriving Potential Coronal Magnetic Fields from Vector Magnetograms
Welsch, Brian T
2015-01-01
The minimum-energy configuration for the magnetic field above the solar photosphere is curl-free (hence, by Ampere's law, also current-free), so can be represented as the gradient of a scalar potential. Since magnetic fields are divergence free, this scalar potential obeys Laplace's equation, given an appropriate boundary condition (BC). With measurements of the full magnetic vector at the photosphere, it is possible to employ either Neumann or Dirichlet BCs there. Historically, the Neumann BC was used, since available line-of-sight magnetic field measurements approximated the radial field needed for the Neumann BC. Since each BC fully determines the 3D vector magnetic field, either choice will, in general, be inconsistent with some aspect of the observed field on the boundary, due to the presence of both currents and noise in the observed field. We present a method to combine solutions from both Dirichlet and Neumann BCs to determine a hybrid potential field that minimizes the integrated square of the residu...
Zhong-Qiang Liu; Su-Rong Jiang; Tamar A. Yinnon; Xiang-Mu Kong; Ying-Jun Li
2014-04-21
Slip-boundary effects on the polar liquid film motor (PLFM) -- a novel micro-fluidic device with important implications for advancing knowledge on liquid micro-film's structure, dynamics, modeling and technology -- are studied. We develop a mathematical model, under slip boundary conditions, describing electro-hydro-dynamical rotations in the PLFMs induced either by direct current (DC) or alternating current (AC) fields. Our main results are: (i) rotation characteristics depend on the ratio $k=l_{s}/D$ ($l_{s}$ denotes the slip length, resulting from the interface's impact on the structure of the liquid and $D$ denotes the film's diameter). (ii) As $k$ ($k>-1/2$) increases: (a) PLFMs subsequently exhibit rotation characteristics under "negative-", "no-", "partial-" and "perfect-" slip boundary conditions; (b) the maximum value of the linear velocity of the steady rotating liquid film increases and its location approaches the film's border; (c) the decay of the angular velocities' dependency on the distance from the center of the film slows down, resulting in a macroscopic flow near the boundary. (iii) In addition to $k$, the rotation characteristics of the AC PLFM depend on the magnitudes, the frequencies, and the phase difference of the AC fields. (iv) Our analytical derived rotation speed distributions are consistent with the existing experimental ones.
Accumulating Particles at the Boundaries of a Laminar Flow
Michael Schindler; Peter Talkner; Marcin Kostur; Peter Hanggi
2007-06-25
The accumulation of small particles is analyzed in stationary flows through channels of variable width at small Reynolds number. The combined influence of pressure, viscous drag and thermal fluctuations is described by means of a Fokker-Planck equation for the particle density. It is shown that in the limit of vanishing particle size a uniform particle distribution is always approached in the long time limit. For extended spherical particles, conditions are specified that lead to inhomogeneous densities and consequently to particle accumulation and depletion. Hereby the boundary conditions for the particle density play a decisive role: The centers of spherical particles must keep the minimal distance of their radius from the fluid boundaries. The normal components of the forces acting on the sphere then may assume finite values which are diffusively transported into the bulk of the fluid.
Warm Bias and Parameterization of Boundary Upwelling in Ocean Models
Cessi, Paola; Wolfe, Christopher
2012-11-06
It has been demonstrated that Eastern Boundary Currents (EBC) are a baroclinic intensification of the interior circulation of the ocean due to the emergence of mesoscale eddies in response to the sharp buoyancy gradients driven by the wind-stress and the thermal surface forcing. The eddies accomplish the heat and salt transport necessary to insure that the subsurface flow is adiabatic, compensating for the heat and salt transport effected by the mean currents. The EBC thus generated occurs on a cross-shore scale of order 20-100 km, and thus this scale needs to be resolved in climate models in order to capture the meridional transport by the EBC. Our result indicate that changes in the near shore currents on the oceanic eastern boundaries are linked not just to local forcing, such as coastal changes in the winds, but depend on the basin-wide circulation as well.
Boundary quantum Knizhnik-Zamolodchikov equations and fusion
Nicolai Reshetikhin; Jasper Stokman; Bart Vlaar
2014-12-19
In this paper we extend our previous results concerning Jackson integral solutions of the boundary quantum Knizhnik-Zamolodchikov equations with diagonal K-operators to higher-spin representations of quantum affine $\\mathfrak{sl}_2$. First we give a systematic exposition of known results on $R$-operators acting in the tensor product of evaluation representations in Verma modules over quantum $\\mathfrak{sl}_2$. We develop the corresponding fusion of $K$-operators, which we use to construct diagonal $K$-operators in these representations. We construct Jackson integral solutions of the associated boundary quantum Knizhnik-Zamolodchikov equations and explain how in the finite-dimensional case they can be obtained from our previous results by the fusion procedure.
Cumulative theoretical uncertainties in lithium depletion boundary age
Tognelli, Emanuele; Degl'Innocenti, Scilla
2015-01-01
We performed a detailed analysis of the main theoretical uncertainties affecting the age at the lithium depletion boundary (LDB). To do that we computed almost 12000 pre-main sequence models with mass in the range [0.06, 0.4] M_sun by varying input physics (nuclear reaction cross-sections, plasma electron screening, outer boundary conditions, equation of state, and radiative opacity), initial chemical elements abundances (total metallicity, helium and deuterium abundances, and heavy elements mixture), and convection efficiency (mixing length parameter, alpha_ML). As a first step, we studied the effect of varying these quantities individually within their extreme values. Then, we analysed the impact of simultaneously perturbing the main input/parameters without an a priori assumption of independence. Such an approach allowed us to build for the first time the cumulative error stripe, which defines the edges of the maximum uncertainty region in the theoretical LDB age. We found that the cumulative error stripe ...
Applying Twisted Boundary Conditions for Few-body Nuclear Systems
Christopher Körber; Thomas Luu
2015-11-20
We describe and implement twisted boundary conditions for the deuteron and triton systems within finite-volumes using the nuclear lattice EFT formalism. We investigate the finite-volume dependence of these systems with different twists angles. We demonstrate how various finite-volume information can be used to improve calculations of binding energies in such a framework. Our results suggests that with appropriate twisting of boundaries, infinite-volume binding energies can be reliably extracted from calculations using modest volume sizes with cubic length $L\\approx8-14$ fm. Of particular importance is our derivation and numerical verification of three-body analogue of `i-periodic' twist angles that eliminate the leading order finite-volume effects to the three-body binding energy.
Applying Twisted Boundary Conditions for Few-body Nuclear Systems
Körber, Christopher
2015-01-01
We describe and implement twisted boundary conditions for the deuteron and triton systems within finite-volumes using the nuclear lattice EFT formalism. We investigate the finite-volume dependence of these systems with different twists angles. We demonstrate how various finite-volume information can be used to improve calculations of binding energies in such a framework. Our results suggests that with appropriate twisting of boundaries, infinite-volume binding energies can be reliably extracted from calculations using modest volume sizes with cubic length $L\\approx8-14$ fm. Of particular importance is our derivation and numerical verification of three-body analogue of `i-periodic' twist angles that eliminate the leading order finite-volume effects to the three-body binding energy.
Flavor twisted boundary conditions and the nucleon vector current
Jiang, F.-J.; Tiburzi, B. C.
2008-12-01
Using flavor twisted boundary conditions, we study nucleon matrix elements of the vector current. We twist only the active quarks that couple to the current. Finite volume corrections due to twisted boundary conditions are determined using partially twisted, partially quenched, heavy baryon chiral perturbation theory, which we develop for the graded group SU(7|5). Asymptotically these corrections are exponentially small in the volume, but can become pronounced for small twist angles. Utilizing the Breit frame does not mitigate volume corrections to nucleon vector current matrix elements. The derived expressions will allow for better controlled extractions of the isovector magnetic moment and the electromagnetic radii from simulations at zero lattice momentum. Our formalism, moreover, can be applied to any nucleon matrix elements.
Steiner, Ullrich
-Watt University) http://www.journaltocs.ac.uk/ #12;HADDON LIBRARY BLISS CLASSIFICATION Overleaf is an outlineHADDON LIBRARY OF ARCHAEOLOGY & ANTHROPOLOGY The Haddon Library is an important collection of published material in the field of archaeology and anthropology. The library holds around 66,000 items
On the Green function of linear evolution equations for a region with a boundary
George Krylov; Marko Robnik
2000-03-30
We derive a closed-form expression for the Green function of linear evolution equations with the Dirichlet boundary condition for an arbitrary region, based on the singular perturbation approach to boundary problems.
An evaluation of grain boundary engineering technology and processing scale-up
Zelinski, Jeffrey A
2005-01-01
Grain boundary engineering is the manipulation of low stacking-fault energy, face- centered cubic material microstructures to break the connectivity of the general grain boundary network through the addition of special ...
Immersed Boundary Methods in the Lattice Boltzmann Equation for Flow Simulation
Kang, Shin Kyu
2012-02-14
In this dissertation, we explore direct-forcing immersed boundary methods (IBM) under the framework of the lattice Boltzmann method (LBM), which is called the direct-forcing immersed boundary-lattice Boltzmann method (IB-LBM). First, we derive...
Boundary conditions, effective action, and Virasoro algebra for AdS?
Porfyriadis, Achilleas P
2010-01-01
We construct an effective action of General Relativity for small excitations from asymptotic transformations and use it to study conformal symmetry in the boundary of AdS3. By requiring finiteness of the boundary effective ...
PERCOLATION ON GRAIN BOUNDARY NETWORKS: APPLICATION TO FISSION GAS RELEASE IN NUCLEAR FUELS
Paul C. Millett
2012-02-01
The percolation behavior of grain boundary networks is characterized in two- and three-dimensional lattices with circular macroscale cross-sections that correspond to nuclear fuel elements. The percolation of gas bubbles on grain boundaries, and the subsequent percolation of grain boundary networks is the primary mechanism of fission gas release from nuclear fuels. Both radial cracks and radial gradients in grain boundary property distributions are correlated with the fraction of grain boundaries vented to the free surfaces. Our results show that cracks surprisingly do not significantly increase the percolation of uniform grain boundary networks. However, for networks with radial gradients in boundary properties, the cracks can considerably raise the vented grain boundary content.
An Examination of Configurations for Using Infrared to Measure Boundary Layer Transition
Freels, Justin Reed
2012-10-19
Infrared transition location estimates can be fast and useful measurements in wind tunnel and flight tests. Because turbulent boundary layers have a much higher rate of convective heat transfer than laminar boundary layers, a difference in surface...
12. First Results on the Regularity of the Free Boundary 12.1 ...
2007-02-22
12.1. Problem A: C1-regularity of the free boundary near low-energy points. In this lecture, we study the free boundary in Problem A near the low- energy points.
Influence of grain boundary energy on the nucleation of complexion transitions
Rohrer, Gregory S.
Influence of grain boundary energy on the nucleation of complexion transitions Stephanie A different transition tem- peratures. It has been hypothesized that higher energy grain boundaries have relative energies preferentially undergo complexion transitions. Our experiment uses a unique sandwich
Ovid'ko Ilya A.
99Amorphous intergranular boundaries as toughening elements in nanocrystalline ceramics © 2009-mail: ovidko@def.ipme.ru AMORPHOUS INTERGRANULAR BOUNDARIES AS TOUGHENING ELEMENTS IN NANOCRYSTALLINE CERAMICS ceramics. Within the model, im- mobile lattice dislocations are generated at amorphous intergranular
A non standard free-boundary problem arising from stratigraphy Gerard GAGNEUX
A non standard free-boundary problem arising from stratigraphy G´erard GAGNEUX Laboratory.4) #12;A non standard free-boundary problem arising from stratigraphy 3 · the initial condition: u(0
Massive Gravity from Higher Derivative Gravity with Boundary Conditions
Minjoon Park; Lorenzo Sorbo
2012-10-29
With an appropriate choice of parameters, a higher derivative theory of gravity can describe a normal massive sector and a ghost massless sector. We show that, when defined on an asymptotically de Sitter spacetime with Dirichlet boundary conditions, such a higher derivative gravity can provide a framework for a unitary theory of massive gravity in four spacetime dimensions. The resulting theory is free not only of higher derivative ghosts but also of the Boulware-Deser mode.
On the extraction of spectral quantities with open boundary conditions
Mattia Bruno; Piotr Korcyl; Tomasz Korzec; Stefano Lottini; Stefan Schaefer
2014-11-19
We discuss methods to extract decay constants, meson masses and gluonic observables in the presence of open boundary conditions. The ensembles have been generated by the CLS effort and have 2+1 flavors of O(a)-improved Wilson fermions with a small twisted-mass term as proposed by L\\"uscher and Palombi. We analyse the effect of the associated reweighting factors on the computation of different observables.
Exchanges across Land-Water-Scape Boundaries in Urban Systems
Vermont, University of
, and institutional behavior Key words: urban; cities; watershed; boundaries; nitrate; water; pollution; land cover Pollution M.L. Cadenasso,a S.T.A. Pickett,b P.M. Groffman,b L.E. Band,c G.S. Brush,d M.F. Galvin,e J Resources, University of Vermont, Burlington, Vermont, USA k Baltimore City Department of Public Works
On Lyapunov boundary control of unstable magnetohydrodynamic plasmas
Tasso, H. [Max-Planck-Institut fuer Plasmaphysik, Euratom Association, 85748 Garching bei Muenchen (Germany); Throumoulopoulos, G. N. [Department of Physics, University of Ioannina, Association Euratom-Hellenic Republic, GR 451 10 Ioannina (Greece)
2013-02-15
Starting from a simple, marginally stable model considered for Lyapunov based boundary control of flexible mechanical systems, we add a term driving an instability and prove that for an appropriate control condition the system can become Lyapunov stable. A similar approximate extension is found for the general energy principle of linearized magnetohydrodynamics. The implementation of such external instantaneous actions may, however, impose challenging constraints for fusion plasmas.
Post measurement bipartite entanglement entropy in conformal field theories
M. A. Rajabpour
2015-08-06
We derive exact formulas for bipartite von Neumann entanglement entropy after partial projective local measurement in $1+1$ dimensional conformal field theories with periodic and open boundary conditions. After defining the set up we will check numerically the validity of our results in the case of Klein-Gordon field theory (coupled harmonic oscillators) and spin-$1/2$ XX chain in a magnetic field. The agreement between analytical results and the numerical calculations is very good. We also find a lower bound for localizable entanglement in coupled harmonic oscillators.
Approximations of very weak solutions to boundary-value problems.
Berggren, Martin Olof
2003-03-01
Standard weak solutions to the Poisson problem on a bounded domain have square-integrable derivatives, which limits the admissible regularity of inhomogeneous data. The concept of solution may be further weakened in order to define solutions when data is rough, such as for inhomogeneous Dirichlet data that is only square-integrable over the boundary. Such very weak solutions satisfy a nonstandard variational form (u, v) = G(v). A Galerkin approximation combined with an approximation of the right-hand side G defines a finite-element approximation of the very weak solution. Applying conforming linear elements leads to a discrete solution equivalent to the text-book finite-element solution to the Poisson problem in which the boundary data is approximated by L{sub 2}-projections. The L{sub 2} convergence rate of the discrete solution is O(h{sub s}) for some s {element_of} (0,1/2) that depends on the shape of the domain, asserting a polygonal (two-dimensional) or polyhedral (three-dimensional) domain without slits and (only) square-integrable boundary data.
Coupled wake boundary layer model of wind-farms
Stevens, Richard J A M; Meneveau, Charles
2014-01-01
We present and test a coupled wake boundary layer (CWBL) model that describes the distribution of the power output in a wind-farm. The model couples the traditional, industry-standard wake expansion/superposition approach with a top-down model for the overall wind-farm boundary layer structure. The wake expansion/superposition model captures the effect of turbine positioning, while the top-down portion adds the interaction between the wind-turbine wakes and the atmospheric boundary layer. Each portion of the model requires specification of a parameter that is not known a-priori. For the wake model the wake expansion coefficient is required, while the top-down model requires an effective span-wise turbine spacing within which the model's momentum balance is relevant. The wake expansion coefficient is obtained by matching the predicted mean velocity at the turbine from both approaches, while the effective span-wise turbine spacing depends on turbine positioning and thus can be determined from the wake expansion...
Gapped Domain Walls, Gapped Boundaries and Topological Degeneracy
Tian Lan; Juven Wang; Xiao-Gang Wen
2014-11-26
Gapped domain walls, as topological line defects between 2+1D topologically ordered states, are examined. We provide simple criteria to determine the existence of gapped domain walls, which apply to both Abelian and non-Abelian topological orders. Our criteria also determine which 2+1D topological orders must have gapless edge modes, namely which 1+1D global gravitational anomalies ensure gaplessness. Furthermore, we introduce a new mathematical object, the tunneling matrix $\\mathcal W$, whose entries are the fusion-space dimensions $\\mathcal W_{ia}$, to label different types of gapped domain walls. By studying many examples, we find evidence that the tunneling matrices are powerful quantities to classify different types of gapped domain walls. Since a gapped boundary is a gapped domain wall between a bulk topological order and the vacuum, regarded as the trivial topological order, our theory of gapped domain walls inclusively contains the theory of gapped boundaries. In addition, we derive a topological ground state degeneracy formula, applied to arbitrary orientable spatial 2-manifolds with gapped domain walls, including closed 2-manifolds and open 2-manifolds with gapped boundaries.
Stability boundaries for wrinkling in highly stretched elastic sheets
Qingdu Li; Timothy J. Healey
2015-09-14
We determine stability boundaries for the wrinkling of highly uni-directionally stretched, finely thin, rectangular elastic sheets. For a given fine thickness and length, a stability boundary here is a curve in the parameter plane, aspect ratio vs. the macroscopic strain; the values on one side of the boundary are associated with a flat, unwrinkled state, while wrinkled configurations correspond to all values on the other. In our recent work we demonstrated the importance of finite elasticity in the membrane part of such a model in order to capture the correct phenomena. Here we present and compare results for four distinct models:(i) the popular F\\"oppl-von K\\'arm\\'an plate model (FvK), (ii) a correction of the latter, used in our earlier work, in which the approximate 2D F\\"oppl strain tensor is replaced by the exact Green strain tensor, (iii) and (iv): effective 2D finite-elasticity membrane models based on 3D incompressible neo-Hookean and Mooney-Rivlin materials, respectively. In particular, (iii) and (iv) are superior models for elastomers. The 2D nonlinear, hyperelastic models (ii)-(iv) all incorporate the same quadratic bending energy used in FvK. Our results illuminate serious shortcomings of the latter in this problem, while also pointing to inaccuracies of model (ii), in spite of yielding the correct qualitative phenomena in our earlier work. In each of these, the shortcoming is a due to a deficiency of the membrane part of the model.
Improving Subtropical Boundary Layer Cloudiness in the 2011 NCEP GFS
Fletcher, J. K.; Bretherton, Christopher S.; Xiao, Heng; Sun, Ruiyu N.; Han, J.
2014-09-23
The current operational version of National Centers for Environmental Prediction (NCEP) Global Forecasting System (GFS) shows significant low cloud bias. These biases also appear in the Coupled Forecast System (CFS), which is developed from the GFS. These low cloud biases degrade seasonal and longer climate forecasts, particularly of short-wave cloud radiative forcing, and affect predicted sea surface temperature. Reducing this bias in the GFS will aid the development of future CFS versions and contributes to NCEP's goal of unified weather and climate modelling. Changes are made to the shallow convection and planetary boundary layer parameterisations to make them more consistent with current knowledge of these processes and to reduce the low cloud bias. These changes are tested in a single-column version of GFS and in global simulations with GFS coupled to a dynamical ocean model. In the single-column model, we focus on changing parameters that set the following: the strength of shallow cumulus lateral entrainment, the conversion of updraught liquid water to precipitation and grid-scale condensate, shallow cumulus cloud top, and the effect of shallow convection in stratocumulus environments. Results show that these changes improve the single-column simulations when compared to large eddy simulations, in particular through decreasing the precipitation efficiency of boundary layer clouds. These changes, combined with a few other model improvements, also reduce boundary layer cloud and albedo biases in global coupled simulations.
Recursive recovery of Markov transition probabilities from boundary value data
Patch, S.K.
1994-04-01
In an effort to mathematically describe the anisotropic diffusion of infrared radiation in biological tissue Gruenbaum posed an anisotropic diffusion boundary value problem in 1989. In order to accommodate anisotropy, he discretized the temporal as well as the spatial domain. The probabilistic interpretation of the diffusion equation is retained; radiation is assumed to travel according to a random walk (of sorts). In this random walk the probabilities with which photons change direction depend upon their previous as well as present location. The forward problem gives boundary value data as a function of the Markov transition probabilities. The inverse problem requires finding the transition probabilities from boundary value data. Problems in the plane are studied carefully in this thesis. Consistency conditions amongst the data are derived. These conditions have two effects: they prohibit inversion of the forward map but permit smoothing of noisy data. Next, a recursive algorithm which yields a family of solutions to the inverse problem is detailed. This algorithm takes advantage of all independent data and generates a system of highly nonlinear algebraic equations. Pluecker-Grassmann relations are instrumental in simplifying the equations. The algorithm is used to solve the 4 {times} 4 problem. Finally, the smallest nontrivial problem in three dimensions, the 2 {times} 2 {times} 2 problem, is solved.
Oil and Gas field code master list 1995
1995-12-01
This is the fourteenth annual edition of the Energy Information Administration`s (EIA) Oil and Gas Field Code Master List. It reflects data collected through October 1995 and provides standardized field name spellings and codes for all identified oil and/or gas fields in the US. The Field Code Index, a listing of all field names and the States in which they occur, ordered by field code, has been removed from this year`s publications to reduce printing and postage costs. Complete copies (including the Field Code Index) will be available on the EIA CD-ROM and the EIA World-Wide Web Site. Future editions of the complete Master List will be available on CD-ROM and other electronic media. There are 57,400 field records in this year`s Oil and Gas Field Code Master List. As it is maintained by EIA, the Master List includes the following: field records for each State and county in which a field resides; field records for each offshore area block in the Gulf of Mexico in which a field resides; field records for each alias field name (see definition of alias below); and fields crossing State boundaries that may be assigned different names by the respective State naming authorities. Taking into consideration the double-counting of fields under such circumstances, EIA identifies 46,312 distinct fields in the US as of October 1995. This count includes fields that no longer produce oil or gas, and 383 fields used in whole or in part for oil or gas Storage. 11 figs., 6 tabs.
Heterotic $?$'-corrections in Double Field Theory
Oscar A. Bedoya; Diego Marques; Carmen Nunez
2014-12-15
We extend the generalized flux formulation of Double Field Theory to include all the first order bosonic contributions to the $\\alpha '$ expansion of the heterotic string low energy effective theory. The generalized tangent space and duality group are enhanced by $\\alpha'$ corrections, and the gauge symmetries are generated by the usual (gauged) generalized Lie derivative in the extended space. The generalized frame receives derivative corrections through the spin connection with torsion, which is incorporated as a new degree of freedom in the extended bein. We compute the generalized fluxes and find the Riemann curvature tensor with torsion as one of their components. All the four-derivative terms of the action, Bianchi identities and equations of motion are reproduced. Using this formalism, we obtain the first order $\\alpha'$ corrections to the heterotic Buscher rules. The relation of our results to alternative formulations in the literature is discussed and future research directions are outlined.
Internal split field generator
Thundat; Thomas George (Knoxville, TN); Van Neste, Charles W. (Kingston, TN); Vass, Arpad Alexander (Oak Ridge, TN)
2012-01-03
A generator includes a coil of conductive material. A stationary magnetic field source applies a stationary magnetic field to the coil. An internal magnetic field source is disposed within a cavity of the coil to apply a moving magnetic field to the coil. The stationary magnetic field interacts with the moving magnetic field to generate an electrical energy in the coil.
Gopalakrishnan, K.
of the Budget Bill outlines most of the key changes to salaries and benefits, which are summarized below. 1.2% Legislative Salary Increase I. EPA (Faculty and Non-Faculty Employees Exempt from the State Personnel Act) Salary increase guidelines for EPA employees will be approved at the August 10 th meeting of the UNC
Johnston, Stephen T.
from southern Yukon to Dease Lake in British Columbia. This paper outlines the stratigraphy component of the stratigraphy. Potential petroleum traps are provided by antiforms, thrust faults article souligne la stratigraphie et la structure, et caractérise l'ensemble du potentiel des ressources
Free Boundary, High Beta Equilibrium in a Large Aspect Ratio Tokamak with Nearly
Free Boundary, High Beta Equilibrium in a Large Aspect Ratio Tokamak with Nearly Circular Plasmaboundary, highbeta equi libria in large aspect ratio tokamaks with a nearly circular plasma boundary in tokamaks for the purpose of developing an economic fusion reactor. It has long been recognized
An Embedded Boundary Integral Solver for the Unsteady Incompressible Navier-Stokes Equations1
Zorin, Denis
An Embedded Boundary Integral Solver for the Unsteady Incompressible Navier-Stokes Equations1-Stokes operator discretization is done using boundary integrals and structured-grid finite elements. We use a two is formulated as a double-layer boundary integral equation. Domain integrals are computed via finite elements
Coremantle boundary topography as a possible constraint on lower mantle chemistry and dynamics
Rhoads, James
Coremantle boundary topography as a possible constraint on lower mantle chemistry and dynamics November 2009 Editor: Y. Ricard Keywords: mantle convection coremantle boundary CMB topography), each of which uniquely affects the topography on Earth's coremantle boundary (CMB). The thermochemical
Boundary energy of the open XXZ chain from new exact solutions
Rajan Murgan; Rafael I. Nepomechie; Chi Shi
2005-12-05
Bethe Ansatz solutions of the open spin-1/2 integrable XXZ quantum spin chain at roots of unity with nondiagonal boundary terms containing two free boundary parameters have recently been proposed. We use these solutions to compute the boundary energy (surface energy) in the thermodynamic limit.
Sharp boundaries of small-and middle-scale solar wind structures
Richardson, John
Sharp boundaries of small- and middle-scale solar wind structures M. O. Riazantseva1 and G. N wind ion flux changes which are not due to shocks. These changes are boundaries of small- and middle boundaries of small- and middle-scale solar wind structures, J. Geophys. Res., 110, A12110, doi:10
Comparing calculated and measured grain boundary energies in nickel Gregory S. Rohrer a
Rohrer, Gregory S.
Comparing calculated and measured grain boundary energies in nickel Gregory S. Rohrer a , Elizabeth boundary energy data sets for Ni. Using these results, we perform the first large-scale comparison between measured and computed grain boundary energies. While the overall correlation between experimental
Dielectric Boundary Force in Molecular Solvation with the PoissonBoltzmann Free Energy: A Shape
Li, Bo
Dielectric Boundary Force in Molecular Solvation with the PoissonÂBoltzmann Free Energy: A Shape boundary force acting on such a boundary is the negative first variation of the elec- trostatic free energy [17,18,35,43,44]. Such a predefined interface is used to compute the solvation free energy as the sum
Response of the bottom boundary layer over a sloping shelf to variations in alongshore wind
to a great extent by flows in the surface and bottom boundary layers (BBL). Wind forcing generates crossResponse of the bottom boundary layer over a sloping shelf to variations in alongshore wind A boundary layer over a sloping shelf to variations in alongshore wind, J. Geophys. Res., 110, C10S09, doi:10
Relative grain boundary area and energy distributions in nickel Jia Li, Shen J. Dillon 1
Rohrer, Gregory S.
Relative grain boundary area and energy distributions in nickel Jia Li, Shen J. Dillon 1 , Gregory crystallographic parameters, a quantity that will be referred to as the grain boundary energy distribution (GBED20]. The first comprehensive measurement of the grain boundary energy distribution was carried out for Mg
Uranium vacancy mobility at the ?5 symmetric tilt and ?5 twist grain boundaries in UO?
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Uberuaga, Blas Pedro; Andersson, David A.
2015-10-01
Ionic transport at grain boundaries in oxides dictates a number of important phenomena, from ionic conductivity to sintering to creep. For nuclear fuels, it also influences fission gas bubble nucleation and growth. Here, using a combination of atomistic calculations and object kinetic Monte Carlo (okMC) simulations, we examine the kinetic pathways associated with uranium vacancies at two model grain boundaries in UO2. The barriers for vacancy motion were calculated using the nudged elastic band method at all uranium sites at each grain boundary and were used as the basis of the okMC simulations. For both boundaries considered – a simplemore »tilt and a simple twist boundary – the mobility of uranium vacancies is significantly higher than in the bulk. For the tilt boundary, there is clearly preferred migration along the tilt axis as opposed to in the perpendicular direction while, for the twist boundary, migration is essentially isotropic within the boundary plane. These results show that cation defect mobility in fluorite-structured materials is enhanced at certain types of grain boundaries and is dependent on the boundary structure with the tilt boundary exhibiting higher rates of migration than the twist boundary.« less
SAID/SAPSrelated VLF waves and the outer radiation belt boundary
Santolik, Ondrej
SAID/SAPSrelated VLF waves and the outer radiation belt boundary Evgeny Mishin,1 Jay Albert,1 for the alteration of the outer radiation belt boundary during (sub)storms. Citation: Mishin, E., J. Albert, and O. Santolik (2011), SAID/SAPSrelated VLF waves and the outer radiation belt boundary, Geophys. Res. Lett., 38
Matched interface and boundary (MIB) method for elliptic problems with sharp-edged interfaces
Zhou, Yongcheng
Matched interface and boundary (MIB) method for elliptic problems with sharp-edged interfaces with sharp-edged interfaces, thin-layered interfaces and interfaces that intersect with geometric boundary. This work generalizes the matched interface and boundary (MIB) method previously designed for solving
H. Itoyama; A. Mironov; A. Morozov
2007-12-02
We describe an algebro-geometric construction of polygon-bounded minimal surfaces in ADS_5, based on consideration of what we call the "boundary ring" of polynomials. The first non-trivial example of the Nambu-Goto (NG) solutions for Z_6-symmetric hexagon is considered in some detail. Solutions are represented as power series, of which only the first terms are evaluated. The NG equations leave a number of free parameters (a free function). Boundary conditions, which fix the free parameters, are imposed on truncated series. It is still unclear if explicit analytic formulas can be found in this way, but even approximate solutions, obtained by truncation of power series, can be sufficient to investigate the Alday-Maldacena -- BDS/BHT version of the string/gauge duality.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Vogelmann, Andrew M.; Fridlind, Ann M.; Toto, Tami; Endo, Satoshi; Lin, Wuyin; Wang, Jian; Feng, Sha; Zhang, Yunyan; Turner, David D.; Liu, Yangang; et al
2015-06-19
Observation-based modeling case studies of continental boundary layer clouds have been developed to study cloudy boundary layers, aerosol influences upon them, and their representation in cloud- and global-scale models. Three 60-hour case study periods span the temporal evolution of cumulus, stratiform, and drizzling boundary layer cloud systems, representing mixed and transitional states rather than idealized or canonical cases. Based on in-situ measurements from the RACORO field campaign and remote-sensing observations, the cases are designed with a modular configuration to simplify use in large-eddy simulations (LES) and single-column models. Aircraft measurements of aerosol number size distribution are fit to lognormal functionsmore »for concise representation in models. Values of the aerosol hygroscopicity parameter, ?, are derived from observations to be ~0.10, which are lower than the 0.3 typical over continents and suggestive of a large aerosol organic fraction. Ensemble large-scale forcing datasets are derived from the ARM variational analysis, ECMWF forecasts, and a multi-scale data assimilation system. The forcings are assessed through comparison of measured bulk atmospheric and cloud properties to those computed in 'trial' large-eddy simulations, where more efficient run times are enabled through modest reductions in grid resolution and domain size compared to the full-sized LES grid. Simulations capture many of the general features observed, but the state-of-the-art forcings were limited at representing details of cloud onset, and tight gradients and high-resolution transients of importance. Methods for improving the initial conditions and forcings are discussed. The cases developed are available to the general modeling community for studying continental boundary clouds.« less
Boundary conditions for conformally coupled scalar in AdS$_4$
Jae-Hyuk Oh
2015-02-05
We consider conformally coupled scalar with $\\phi^4$ coupling in AdS$_4$ and study its various boundary conditions on AdS boundary. We have obtained perturbative solutions of equation of motion of the conformally coupled scalar with power expansion order by order in $\\phi^4$ coupling $\\lambda$ up to $\\lambda^2$ order. In its dual CFT, we get 2,4 and 6 point functions by using this solution with Dirichlet and Neumann boundary conditions via AdS/CFT dictionary. We also consider marginal deformation on AdS boundary and get its on-shell and boundary effective actions.
Crystallographic Characteristics of Grain Boundaries in Dense Yttria-Stabilized Zirconia
Lam Helmick; Shen J. Dillon; Kirk Gerdes; Randall Gemmen; Gregory S. Rohrer; Sridhar Seetharaman; Paul A. Salvador
2010-04-01
Grain-boundary plane, misorientation angle, grain size, and grain-boundary energy distributions were quantified using electron backscatter diffraction data for dense polycrystalline yttria-stabilized zirconia, to understand interfacial crystallography in solid oxide fuel cells. Tape-cast samples were sintered at 14501C for 4 h and annealed for at least 100 h between 8001C and 16501C. Distributions obtained from both three-dimensional (3D) reconstructions and stereological analyses of 2D sections demonstrated that the (100) boundary planes {(111)} have relative areas larger {smaller} than expected in a random distribution, and that the boundary plane distribution is inversely correlated to the boundary energy distribution.
Lie Groupoids in Classical Field Theory I: Noether's Theorem
Costa, Bruno T; Pêgas, Luiz Henrique P
2015-01-01
In the two papers of this series, we initiate the development of a new approach to implementing the concept of symmetry in classical field theory, based on replacing Lie groups/algebras by Lie groupoids/algebroids, which are the appropriate mathematical tools to describe local symmetries when gauge transformations are combined with space-time transformations. Here, we outline the basis of the program and, as a first step, show how to (re)formulate Noether's theorem about the connection between symmetries and conservation laws in this approach.
Propagator of a Charged Particle with a Spin in Uniform Magnetic and Perpendicular Electric Fields
Ricardo Cordero-Soto; Raquel M. Lopez; Erwin Suazo; Sergei K. Suslov
2008-02-05
We construct an explicit solution of the Cauchy initial value problem for the time-dependent Schroedinger equation for a charged particle with a spin moving in a uniform magnetic field and a perpendicular electric field varying with time. The corresponding Green function (propagator) is given in terms of elementary functions and certain integrals of the fields with a characteristic function, which should be found as an analytic or numerical solution of the equation of motion for the classical oscillator with a time-dependent frequency. We discuss a particular solution of a related nonlinear Schroedinger equation and some special and limiting cases are outlined.
MacLaren, Ian Craven, Alan J.; Schaffer, Bernhard; Wang, LiQiu; Ramasse, Quentin M.; Kalantari, Kambiz; Reaney, Ian M.
2014-06-01
Stepped antiphase boundaries are frequently observed in Ti-doped Bi{sub 0.85}Nd{sub 0.15}FeO{sub 3}, related to the novel planar antiphase boundaries reported recently. The atomic structure and chemistry of these steps are determined by a combination of high angle annular dark field and bright field scanning transmission electron microscopy imaging, together with electron energy loss spectroscopy. The core of these steps is found to consist of 4 edge-sharing FeO{sub 6} octahedra. The structure is confirmed by image simulations using a frozen phonon multislice approach. The steps are also found to be negatively charged and, like the planar boundaries studied previously, result in polarisation of the surrounding perovskite matrix.
Heisenberg-picture quantum field theory
Theo Johnson-Freyd
2015-08-24
This paper discusses what we should mean by "Heisenberg-picture quantum field theory." Atiyah--Segal-type axioms do a good job of capturing the "Schr\\"odinger picture": these axioms define a "$d$-dimensional quantum field theory" to be a symmetric monoidal functor from an $(\\infty,d)$-category of "spacetimes" to an $(\\infty,d)$-category which at the second-from-top level consists of vector spaces, so at the top level consists of numbers. This paper argues that the appropriate parallel notion "Heisenberg picture" should also be defined in terms of symmetric monoidal functors from the category of spacetimes, but the target should be an $(\\infty,d)$-category that in top dimension consists of pointed vector spaces instead of numbers; the second-from-top level can be taken to consist of associative algebras or of pointed categories. The paper ends by outlining two sources of such Heisenberg-picture field theories: factorization algebras and skein theory.
Field study plan for alternate barriers
Freeman, H.D.; Gee, G.W.; Relyea, J.F.
1989-05-01
Pacific Northwest Laboratory (PNL) is providing technical assistance in selecting, designing, evaluating, and demonstrating protective barriers. As part of this technical assistance effort, asphalt, clay, and chemical grout will be evaluated for use as alternate barriers. The purpose of the subsurface layer is to reduce the likelihood that extreme events (i.e., 100-year maximum storms, etc.) will cause significant drainage through the barrier. The tests on alternate barriers will include laboratory and field analysis of the subsurface layer performance. This field test plan outlines the activities required to test and design subsurface moisture barriers. The test plan covers activities completed in FY 1988 and planned through FY 1992 and includes a field-scale test of one or more of the alternate barriers to demonstrate full-scale application techniques and to provide performance data on a larger scale. Tests on asphalt, clay, and chemical grout were initiated in FY 1988 in small (30.5 cm diameter) tube-layer lysimeters. The parameters used for testing the materials were different for each one. The tests had to take into account the differences in material characteristics and response to change in conditions, as well as information provided by previous studies. 33 refs., 8 figs., 1 tab.
Molecular dynamics simulations of grain boundary thermal resistance in UO2
Tianyi Chen; Di Chen; Bulent H. Sencer; Lin Shao
2014-09-01
By means of molecular dynamics (MD) simulations, we have calculated Kaptiza resistance of UO2 with or without radiation damage. For coincident site lattice boundaries of different configurations, the boundary thermal resistance of unirradiated UO2 can be well described by a parameter-reduced formula by using boundary energies as variables. We extended the study to defect-loaded UO2 by introducing damage cascades in close vicinity to the boundaries. Following cascade annealing and defect migrations towards grain boundaries, the boundary energy increases and so does Kaptiza resistance. The correlations between these two still follow the same formula extracted from the unirradiated UO2. The finding will benefit multi-scale modeling of UO2 thermal properties under extreme radiation conditions by combining effects from boundary configurations and damage levels.
Turbine exhaust diffuser with region of reduced flow area and outer boundary gas flow
Orosa, John
2014-03-11
An exhaust diffuser system and method for a turbine engine. The outer boundary may include a region in which the outer boundary extends radially inwardly toward the hub structure and may direct at least a portion of an exhaust flow in the diffuser toward the hub structure. At least one gas jet is provided including a jet exit located on the outer boundary. The jet exit may discharge a flow of gas downstream substantially parallel to an inner surface of the outer boundary to direct a portion of the exhaust flow in the diffuser toward the outer boundary to effect a radially outward flow of at least a portion of the exhaust gas flow toward the outer boundary to balance an aerodynamic load between the outer and inner boundaries.
Preliminary Phase Field Computational Model Development
Li, Yulan; Hu, Shenyang Y.; Xu, Ke; Suter, Jonathan D.; McCloy, John S.; Johnson, Bradley R.; Ramuhalli, Pradeep
2014-12-15
This interim report presents progress towards the development of meso-scale models of magnetic behavior that incorporate microstructural information. Modeling magnetic signatures in irradiated materials with complex microstructures (such as structural steels) is a significant challenge. The complexity is addressed incrementally, using the monocrystalline Fe (i.e., ferrite) film as model systems to develop and validate initial models, followed by polycrystalline Fe films, and by more complicated and representative alloys. In addition, the modeling incrementally addresses inclusion of other major phases (e.g., martensite, austenite), minor magnetic phases (e.g., carbides, FeCr precipitates), and minor nonmagnetic phases (e.g., Cu precipitates, voids). The focus of the magnetic modeling is on phase-field models. The models are based on the numerical solution to the Landau-Lifshitz-Gilbert equation. From the computational standpoint, phase-field modeling allows the simulation of large enough systems that relevant defect structures and their effects on functional properties like magnetism can be simulated. To date, two phase-field models have been generated in support of this work. First, a bulk iron model with periodic boundary conditions was generated as a proof-of-concept to investigate major loop effects of single versus polycrystalline bulk iron and effects of single non-magnetic defects. More recently, to support the experimental program herein using iron thin films, a new model was generated that uses finite boundary conditions representing surfaces and edges. This model has provided key insights into the domain structures observed in magnetic force microscopy (MFM) measurements. Simulation results for single crystal thin-film iron indicate the feasibility of the model for determining magnetic domain wall thickness and mobility in an externally applied field. Because the phase-field model dimensions are limited relative to the size of most specimens used in experiments, special experimental methods were devised to create similar boundary conditions in the iron films. Preliminary MFM studies conducted on single and polycrystalline iron films with small sub-areas created with focused ion beam have correlated quite well qualitatively with phase-field simulations. However, phase-field model dimensions are still small relative to experiments thus far. We are in the process of increasing the size of the models and decreasing specimen size so both have identical dimensions. Ongoing research is focused on validation of the phase-field model. Validation is being accomplished through comparison with experimentally obtained MFM images (in progress), and planned measurements of major hysteresis loops and first order reversal curves. Extrapolation of simulation sizes to represent a more stochastic bulk-like system will require sampling of various simulations (i.e., with single non-magnetic defect, single magnetic defect, single grain boundary, single dislocation, etc.) with distributions of input parameters. These outputs can then be compared to laboratory magnetic measurements and ultimately to simulate magnetic Barkhausen noise signals.
Quantization of exciton in magnetic field background
Pulak Ranjan Giri; S. K. Chakrabarti
2007-11-22
The possible mismatch between the theoretical and experimental absorption of the edge peaks in semiconductors in a magnetic field background may arise due to the approximation scheme used to analytically calculate the absorption coefficient. As a possible remedy we suggest to consider nontrivial boundary conditions on x-y plane by in-equivalently quantizing the exciton in background magnetic field. This inequivalent quantization is based on von Neumann's method of self-adjoint extension, which is characterized by a parameter \\Sigma. We obtain bound state solution and scattering state solution, which in general depend upon the self-adjoint extension parameter \\Sigma. The parameter \\Sigma can be used to fine tune the optical absorption coefficient K(\\Sigma) to match with the experiment.
Control of stochasticity in magnetic field lines
Cristel Chandre; Michel Vittot; Guido Ciraolo; Philippe Ghendrih; Ricardo Lima
2005-11-03
We present a method of control which is able to create barriers to magnetic field line diffusion by a small modification of the magnetic perturbation. This method of control is based on a localized control of chaos in Hamiltonian systems. The aim is to modify the perturbation locally by a small control term which creates invariant tori acting as barriers to diffusion for Hamiltonian systems with two degrees of freedom. The location of the invariant torus is enforced in the vicinity of the chosen target. Given the importance of confinement in magnetic fusion devices, the method is applied to two examples with a loss of magnetic confinement. In the case of locked tearing modes, an invariant torus can be restored that aims at showing the current quench and therefore the generation of runaway electrons. In the second case, the method is applied to the control of stochastic boundaries allowing one to define a transport barrier within the stochastic boundary and therefore to monitor the volume of closed field lines.
Cambridge, University of
. Confinement of the Sun's interior magnetic field: some exact boundary-layer solutions T. S. Wood and M. E. Mc. The profiles of velocity and magnetic field within the confinement layer are fixed by two external conditions, solar tachocline, interior magnetic field confinement, Ferraro constraint, helium settling layer, helium
Chatterjee, Vijay; Harniman, Robert; May, Paul W.; Barhai, P. K.
2014-04-28
The emission of electrons from diamond in vacuum occurs readily as a result of the negative electron affinity of the hydrogenated surface due to features with nanoscale dimensions, which can concentrate electric fields high enough to induce electron emission from them. Electrons can be emitted as a result of an applied electric field (field emission) with possible uses in displays or cold-cathode devices. Alternatively, electrons can be emitted simply by heating the diamond in vacuum to temperatures as low as 350?°C (thermionic emission), and this may find applications in solar energy generation or energy harvesting devices. Electron emission studies usually use doped polycrystalline diamond films deposited onto Si or metallic substrates by chemical vapor deposition, and these films have a rough, faceted morphology on the micron or nanometer scale. Electron emission is often improved by patterning the diamond surface into sharp points or needles, the idea being that the field lines concentrate at the points lowering the barrier for electron emission. However, there is little direct evidence that electrons are emitted from these sharp tips. The few reports in the literature that have studied the emission sites suggested that emission came from the grain boundaries and not the protruding regions. We now present direct observation of the emission sites over a large area of polycrystalline diamond using tunneling atomic force microscopy. We confirm that the emission current comes mostly from the grain boundaries, which is consistent with a model for emission in which the non-diamond phase is the source of electrons with a threshold that is determined by the surrounding hydrogenated diamond surface.
NEUTRINO SPIN AND FLAVOUR CONVERSION AND OSCILLATIONS IN MAGNETIC FIELD
A. M. Egorov; G. G. Likhachev; A. I. Studenikin
1995-06-09
A review of the neutrino conversion and oscillations among the two neutrino species (active and sterile) induced by strong twisting magnetic field is presented and implications to neutrinos in neutron star, supernova, the Sun and interstellar galactic media are discussed. The ``cross-boundary effect" (CBE) (i.e., a possible conversion of one half of neutrinos of the bunch from active into sterile specie) at the surface of neutron star is also studied for a realistic neutron star structure.
External split field generator
Thundat, Thomas George (Knoxville, TN); Van Neste, Charles W. (Kingston, TN); Vass, Arpad Alexander (Oak Ridge, TN)
2012-02-21
A generator includes a coil disposed about a core. A first stationary magnetic field source may be disposed on a first end portion of the core and a second stationary magnetic field source may be disposed on a second end portion of core. The first and second stationary magnetic field sources apply a stationary magnetic field to the coil. An external magnetic field source may be disposed outside the coil to apply a moving magnetic field to the coil. Electrical energy is generated in response to an interaction between the coil, the moving magnetic field, and the stationary magnetic field.
Statistical mechanics of the nonlinear Schroedinger equation. II. Mean field approximation
Lebowitz, J.L.; Rose, H.A.; Speer, E.R.
1989-01-01
The authors investigate a mean field approximation to the statistical mechanics of complex fields with dynamics governed by the nonlinear Schroedinger equation. Such fields, whose Hamiltonian is unbounded below, may model plasmas, lasers, and other physical systems. Restricting themselves to one-dimensional systems with periodic boundary conditions, we find in the mean field approximation a phase transition from a uniform regime to a regime in which the system is dominated by solitons. They compute explicitly, as a function of temperature and density (L/sup 2/ norm), the transition point at which the uniform configuration becomes unstable to local perturbations; static and dynamic mean field approximations yield the same result.
Frictional anisotropy under boundary lubrication: effect of surface texture.
Ajayi, O. O.; Erck, R. A.; Lorenzo-Martin, C.; Fenske, G. R.; Energy Systems
2009-06-15
The friction coefficient was measured under boundary lubrication with a ball-on-flat contact configuration in unidirectional sliding. The ball was smooth and hardened 52100 steel. Discs were made from case-carburized and hardened 4620, annealed 1080, and 1018 steels with directionally ground surfaces. A synthetic lubricant of stock polyalphaolefin was used for testing. During testing with each material, a frictional spike was observed whenever the ball slid parallel to the grinding ridge on the disc surface. The average friction coefficient for all tests was about 0.1, which is typical for the boundary lubrication regime. The magnitude of the frictional spikes, which reached as high as a friction coefficient of 0.25, and their persistence depended on the hardness of the disc surface. On the basis of elastohydrodynamic theory, coupled with the observation of severe plastic deformation on the ridges parallel to the sliding direction, the frictional spike could be due to localized plastic deformation on the disc surface at locations of minimal thickness for the lubricant fluid film. This hypothesis was further supported by lack of frictional spikes in tests using discs coated with a thin film of diamond-like carbon, in which plastic deformation is minimal.
Fluorescence photon migration by the boundary element method
Fedele, Francesco; Eppstein, Margaret J. . E-mail: maggie.eppstein@uvm.edu; Laible, Jeffrey P.; Godavarty, Anuradha; Sevick-Muraca, Eva M.
2005-11-20
The use of the boundary element method (BEM) is explored as an alternative to the finite element method (FEM) solution methodology for the elliptic equations used to model the generation and transport of fluorescent light in highly scattering media, without the need for an internal volume mesh. The method is appropriate for domains where it is reasonable to assume the fluorescent properties are regionally homogeneous, such as when using highly specific molecularly targeted fluorescent contrast agents in biological tissues. In comparison to analytical results on a homogeneous sphere, BEM predictions of complex emission fluence are shown to be more accurate and stable than those of the FEM. Emission fluence predictions made with the BEM using a 708-node mesh, with roughly double the inter-node spacing of boundary nodes as in a 6956-node FEM mesh, match experimental frequency-domain fluorescence emission measurements acquired on a 1087 cm{sup 3} breast-mimicking phantom at least as well as those of the FEM, but require only 1/8 to 1/2 the computation time.
Thermographic analysis of turbulent non-isothermal water boundary layer
Znamenskaya, Irina A
2015-01-01
The paper is devoted to the investigation of the turbulent water boundary layer in the jet mixing flows using high-speed infrared (IR) thermography. Two turbulent mixing processes were studied: a submerged water jet impinging on a flat surface and two intersecting jets in a round disc-shaped vessel. An infrared camera (FLIR Systems SC7700) was focused on the window transparent for IR radiation; it provided high-speed recordings of heat fluxes from a thin water layer close to the window. Temperature versus time curves at different points of water boundary layer near the wall surface were acquired using the IR camera with the recording frequency of 100 Hz. The time of recording varied from 3 till 20 min. The power spectra for the temperature fluctuations at different points on the hot-cold water mixing zone were calculated using the Fast Fourier Transform algorithm. The obtained spectral behavior was compared to the Kolmogorov "-5/3 spectrum" (a direct energy cascade) and the dual-cascade scenario predicted for...